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nanomaterials , such as nanoparticles , nanotubes , fullerenes , nanowires , and quantum dots , have been developed in numerous research laboratories because they have a much greater surface area to mass ratio than micro - scale material , and they have been adopted in many new technologies . the unique properties and applications of nanoparticles derive from numerous attributes ; biomolecules , such as proteins , polynucleic acids , and nanoparticles made of metals and semiconductor materials , can serve as magnetic carriers and can provide fluorescence .
the use of nanoparticles for clinical applications presents a risk and has the potential for exposure to a toxic hazard .
acute aquatic methods are a convenient analysis of nanoparticle toxicity , and the method uses various organisms including bacteria vibrio fischeri , daphnia magna , and thamnocephalus platyurus .
further , to analyze the in vitro toxicity of nanoparticles and micro - scale materials , the interactions between particles and bacteria and their surface properties were investigated .
titanium dioxide ( tio2 ) is widely used and is high insoluble and thermally stable .
since it has excellent optical performance and electrical properties , tio2 has been used for the development solar cell energy .
in addition , it is used as a cosmetic to protect the skin from sunlight ( e.g. a sunblock ) and as a pigment to block water from penetrating a house .
based on these characteristics of tio2 , we investigated toxicity via cellular response by the injection of various nanoparticles and solutions in organisms ( e.g. mice , daphnia magna ) . in this study
, we conducted an experiment to measure the toxicity of tio2 nanoparticles via a size- and concentrationdependent manner through in vivo acute and chronic toxicity testing using a d. magna according to international standards .
the aim of this study was to analyze both the acute and chronic toxicity using d. magna and to meet these goals , we have used three different types of tio2 particles , i.e. anatase sized 250 nm and 21 nm , and rutile sized 500 nm .
the d. magna used in this study was provided by the korea institute of toxicology ( daejeon , korea ) .
the d. magna was cultured and treated as described in the us environmental protection agency ( us epa ) manual .
d. magna cultured and raised in a chamber were retained at 201 in 2 l beakers containing 1.5 l of hard , reconstituted water ( 0.008
g l kcl , 0.12 g l caco3 , 0.12 g l mgso4 , and 0.192 g l nahco3 in distilled water filtered through a minipore milli - q apparatus ) . for performance of the reproduction tests the ph of the medium
the medium for the d. magna culture was changed three times per week with fresh hrw(hard reconstituted water ) and fed with green algae ( selenastrum capricornutum ) and ytc ( a mixture of yeast , cerophyll , and trout chow ) purchased from aquatic biosystem inc .
d. magna culture was maintained in 2-liter glass beakers containing 1.6 l of cultured medium and 30 - 50 daphnids .
the acute toxicity test was performed according to the standard protocol for d. magna acute test .
approximately 30 neonates aged less than 24 hours were separated in to three groups and exposed to titanium ( iv ) oxide ( sigma , us ) with different sizes and several concentrations for 96 hours in a static test .
all test concentrations were prepared using a volume of 50 ml in triplicate and maintained at 201 during a 96-hours photoperiod of 16 hours light : 8 hours dark without any feeding .
the chronic toxicity test was performed according to the standard protocol through d. magna chronic toxicity testing ; neonates aged less than 24 hours at the start of the test were exposed to approximately three concentrations of each size of the nanoparticles for a period of 21 days .
neonates were fed two to three times per week , and the media and nanoparticle solution were changed , simultaneously .
the test beakers were maintained in a chamber at 201 during a 96 hours photoperiod of 16 hours light : 8 hours dark .
all of the data were obtained from three independent samples carried out simultaneously for error analysis , and the results were shown along with the standard deviation and the correlation between the mortality under several experimental conditions .
the d. magna used in this study was provided by the korea institute of toxicology ( daejeon , korea ) .
the d. magna was cultured and treated as described in the us environmental protection agency ( us epa ) manual .
d. magna cultured and raised in a chamber were retained at 201 in 2 l beakers containing 1.5 l of hard , reconstituted water ( 0.008
g l kcl , 0.12 g l caco3 , 0.12 g l mgso4 , and 0.192 g l nahco3 in distilled water filtered through a minipore milli - q apparatus ) . for performance of the reproduction tests the ph of the medium
the medium for the d. magna culture was changed three times per week with fresh hrw(hard reconstituted water ) and fed with green algae ( selenastrum capricornutum ) and ytc ( a mixture of yeast , cerophyll , and trout chow ) purchased from aquatic biosystem inc .
d. magna culture was maintained in 2-liter glass beakers containing 1.6 l of cultured medium and 30 - 50 daphnids .
the acute toxicity test was performed according to the standard protocol for d. magna acute test .
approximately 30 neonates aged less than 24 hours were separated in to three groups and exposed to titanium ( iv ) oxide ( sigma , us ) with different sizes and several concentrations for 96 hours in a static test .
all test concentrations were prepared using a volume of 50 ml in triplicate and maintained at 201 during a 96-hours photoperiod of 16 hours light : 8 hours dark without any feeding .
the chronic toxicity test was performed according to the standard protocol through d. magna chronic toxicity testing ; neonates aged less than 24 hours at the start of the test were exposed to approximately three concentrations of each size of the nanoparticles for a period of 21 days .
neonates were fed two to three times per week , and the media and nanoparticle solution were changed , simultaneously .
the test beakers were maintained in a chamber at 201 during a 96 hours photoperiod of 16 hours light : 8 hours dark .
all of the data were obtained from three independent samples carried out simultaneously for error analysis , and the results were shown along with the standard deviation and the correlation between the mortality under several experimental conditions .
the acute toxicity of the three other sizes of titanium ( iv ) oxide was investigated using a 96-hours toxicity test with 10 neonates of d. magna ( less than 24-hours old ) in one beaker .
the chronic toxicity test of the three other sizes of titanium ( iv ) oxide was performed for 21 days using 10 neonates with one neonate in each beaker .
we performed the acute toxicity test for 96 hours with various concentrations and sizes of tio2 particles .
sodium phosphate buffer ( ph 6 , 0.1 m ) was used as the control , and its mortality was shown in figure 1 .
after 96 hours , four neonates treated with anatase ( 250 nm ) and rutile ( 500 nm ) particles at 8 mm survived , but of those treated with anatase ( 21 nm ) at 0.75 mm , four survived .
from these results , we determined that the higher concentration led to a higher mortality ( see all graphs ) .
furthermore , the smaller size led to a higher mortality ( figure 1c ) . given these results , we found that the regression curves of the acute toxicity data , lc50 and lc20 were determined as the lethal concentrations of a chemical when the percentage of d. magna mortality was 50% and 20% , respectively . in this study ,
d. magna was exposed to two different lc values ( lc20 , lc50 ) of anatase ( 250 nm ) 1.29 and 3.47 mm , respectively , for 96 hours to examine the effects of the anatase form ( 250 nm ) of tio2 ( figure 2a ) .
likewise , characteristics of the rutile ( 500 nm ) and anatase ( 21 nm ) varieties were measured .
the lc20 and 50 of the rutile ( 500 nm ) and anatase type ( 21 nm ) particles were 1.98 , 5.94 , 0.19 , and 0.42 mm , respectively ( figure 2b , c ) . based on the above results , the d. magna toxicity of the three types of tio2 particles decreased from anatase ( 21 nm ) to anatase ( 250 nm ) to rutile ( 500 nm ) particles . in addition , the chronic toxicity over 21 days using various concentrations and sizes of tio2 particles determined in this study .
moreover , we used and compared the concentrations ( 0 , 1 , 10 mm ) in all chronic toxicity tests .
survival of anatase ( 250 nm ) and rutle ( 500 nm ) were observed at approximately 10 , 40% at 1 mm ( figure 3a , b ) .
in contrast , the survival for 1 mm of anatase ( 21 nm ) particles was not measured because there were killed after the cells were exposed to the solution for 16 days ( figure 3c ) . from these results
, we determined that the toxic response of anatase ( 250 nm ) and rutile ( 500 nm ) progressed slowly , but the response of anatase ( 21 nm ) particles progressed rapidly .
there were more than 120 live offspring of the control after 21 days of testing ( figure 4a ) .
that of the anatase ( 250 nm ) and rutile ( 500 nm ) particles with 1 mm was approximately 80 and 20% , respectively .
however we did not find any neonates after exposure to anatase ( 21 nm ) particles at 1 mm ( figure 4 ) .
further , we found that no offspring were found at the 10 mm concentration of additional sizes of tio2 ( figure 4c ) .
after finishing the chronic toxicity tests , we measured the size of neonates living until last day using microscope .
averagely , the size of neonates with 0 , 1 , and 10 mm anatase ( 250 nm ) materials is 4 , 3 , and 2 centimeters , respectively . for rutile ( 500 nm )
nanoparticles , the sizes are 4 , 2.5 , and 2 centimeters , respectively ( figure 5 ) .
however , the size of anatase ( 21 nm ) particles could not be measured because all neonates died .
we performed the acute toxicity test for 96 hours with various concentrations and sizes of tio2 particles .
sodium phosphate buffer ( ph 6 , 0.1 m ) was used as the control , and its mortality was shown in figure 1 .
after 96 hours , four neonates treated with anatase ( 250 nm ) and rutile ( 500 nm ) particles at 8 mm survived , but of those treated with anatase ( 21 nm ) at 0.75 mm , four survived . from these results , we determined that the higher concentration led to a higher mortality ( see all graphs ) .
furthermore , the smaller size led to a higher mortality ( figure 1c ) . given these results , we found that the regression curves of the acute toxicity data , lc50 and lc20 were determined as the lethal concentrations of a chemical when the percentage of d. magna mortality was 50% and 20% , respectively . in this study ,
d. magna was exposed to two different lc values ( lc20 , lc50 ) of anatase ( 250 nm ) 1.29 and 3.47 mm , respectively , for 96 hours to examine the effects of the anatase form ( 250 nm ) of tio2 ( figure 2a ) .
likewise , characteristics of the rutile ( 500 nm ) and anatase ( 21 nm ) varieties were measured . the lc20 and 50 of the rutile ( 500 nm ) and anatase type ( 21 nm )
particles were 1.98 , 5.94 , 0.19 , and 0.42 mm , respectively ( figure 2b , c ) . based on the above results , the d. magna toxicity of the three types of tio2 particles decreased from anatase ( 21 nm ) to anatase ( 250 nm ) to rutile ( 500 nm ) particles .
in addition , the chronic toxicity over 21 days using various concentrations and sizes of tio2 particles determined in this study . moreover , we used and compared the concentrations ( 0 , 1 , 10 mm ) in all chronic toxicity tests .
survival of anatase ( 250 nm ) and rutle ( 500 nm ) were observed at approximately 10 , 40% at 1 mm ( figure 3a , b ) .
in contrast , the survival for 1 mm of anatase ( 21 nm ) particles was not measured because there were killed after the cells were exposed to the solution for 16 days ( figure 3c ) . from these results
, we determined that the toxic response of anatase ( 250 nm ) and rutile ( 500 nm ) progressed slowly , but the response of anatase ( 21 nm ) particles progressed rapidly .
there were more than 120 live offspring of the control after 21 days of testing ( figure 4a ) .
that of the anatase ( 250 nm ) and rutile ( 500 nm ) particles with 1 mm was approximately 80 and 20% , respectively .
however we did not find any neonates after exposure to anatase ( 21 nm ) particles at 1 mm ( figure 4 ) .
further , we found that no offspring were found at the 10 mm concentration of additional sizes of tio2 ( figure 4c ) . after finishing the chronic toxicity tests , we measured the size of neonates living until last day using microscope .
averagely , the size of neonates with 0 , 1 , and 10 mm anatase ( 250 nm ) materials is 4 , 3 , and 2 centimeters , respectively . for rutile ( 500 nm ) nanoparticles ,
the sizes are 4 , 2.5 , and 2 centimeters , respectively ( figure 5 ) .
however , the size of anatase ( 21 nm ) particles could not be measured because all neonates died .
the d. magna showed a very sensitive response dependent upon the size and concentration of tio2 nanoparticles in both acute and chronic toxicity tests .
in particular , the size difference of the nanoparticles demonstrated a greater response than the concentration .
as shown in figure 1 , while the toxicity of anatase ( 250 nm ) and rutile ( 500 nm ) particles demonstrated similarities , the smallest size indicated tio2 induced the greatest toxicity despite the low concentrations of the solution . in a study similar to ours ,
d. magna was used to confirm that toxicity is influenced by the size of tio2 nanoparticles .
furthermore , we investigated the same concentration of anatase ( 250 nm ) and rutile ( 50 nm ) particles to compare the toxicity of three types of tio2 . however , no neonates survived the addition of anatase ( 21 nm ) particles ( data not shown ) .
the result is likely a rapid absorption of the anatase ( 21 nm ) particles in the neonate because of the small size .
we suggest that the neonates have a higher potential for reaching deep into the lungs or damaging internal organs because of the size of tio2 particles .
our innovative approach based on a combination of traditional ecotoxicology methods allowed the clear differentiation of the toxic effects of nonmetal oxide nanoparticles . in addition , this is the first 96-hours evaluation of an acute toxicity test of the size dependence of tio2 using d. magna .
all tio2 nanoparticles tested by d. magna were sensitive to concentration , and d. magna is widely used in aquatic risk assessment . on the basis of these acute toxicity test results , we conducted a chronic , in vivo toxicity test to confirm dependence on the tio2 particle size .
these responses are due to adaptations , such as changes of state , which happen after exposure to toxicant nano - sized materials .
d. magna showed specific response patterns according to toxic effects caused by the size and concentration of tio2 nanoparticles .
therefore , the size effect of tio2 nanoparticles should be considered in hazard evaluations for the potential to impact aquatic life . | objectivestitanium dioxide ( tio2 ) , a common nanoparticle widely used in industrial production , is one of nano - sized materials . the purpose of this study was to determine the acute and chronic toxicity of tio2 using different size and various concentrations on daphnia magna.methodsin the acute toxicity test , four concentrations ( 0 , 0.5 , 4 , and 8 mm ) for tio2 with 250 or 500 nm and five concentrations ( 0 , 0.25 , 0.5 , 0.75 , and 1 mm ) for tio2 with 21 nm were selected to analyze the toxic effect to three groups of ten daphnia neonates over 96 hours .
in addition , to better understand their toxicity , chronic toxicity was examined over 21 days using 0 , 1 , and 10 mm for each type of tio2.resultsour results showed that all organisms died before the reproduction time at a concentration of 10 mm of tio2 .
in addition , the exposure of anatase ( 21 nm ) particles were more toxic to d. magna , comparing with that of anatase ( 250 nm ) and rutile ( 500 nm ) particles.conclusionsthis study indicated that tio2 had adverse impacts on the survival , growth and reproduction of d. magna after the 21days exposure .
in addition , the number of test organisms that were able to reproduce neonates gradually were reduced as the size of tio2 tested was decreased . |
many hospitals have environmental enrichment with paintings and visual art arrangement that can be used by health care professionals in a structured manner .
one way to use hospital art could be that health professionals start a dialogue with a patient inspired by a painting .
the role of health care professionals could be to support and encourage the patient to combine earlier memories and experiences with new impressions from the painting .
the present line of research may prove fruitful in that it could inspire health professionals to seek new directions by which art could be integrated in nursing care .
many hospitals have environmental enrichment with paintings and visual art arrangement that can be used by health care professionals in a structured manner in order to develop nursing care .
one way could be to use hospital art to start a dialogue inspired by a painting .
the relevance of art in nursing care needs to be considered , particularly because it provides a lens through which an alternative nursing care could improve patient care .
health professionals have to take into consideration that patients do need different ways to express their feelings .
it could be alternative non - stigmatizing environments for helping people with mental health problems understand emotional distress .
health professionals could ask the patient to think aloud what they see , think , and feel about the artworks that might expand the patient 's thoughts and , therefore , give health care professionals strategies they need to understand the patient . the development of this understanding is theoretically based and a value of significance in developing nursing care . for the patient , being able to both feel and talk about the characteristic of their life situation could be a help in nursing care .
the research project has designed an approach to scientifically evaluate the effect of visual art dialogues performed over a period of time .
this should be a subject of concern for a wide range of professionals including nurses , policy makers , artists , and administrators .
the present study explores visitor 's perception when a structured art dialogue ( sad ) model was used .
the integration of the sad model will provide an ideal setting for answering the question of the value of the sad model .
the works of art used in the present study are by a swedish painter , anna toresdotter .
the european charter on environment and health declares that good health and well - being require a harmonious environment in which aesthetic , social , physical , and psychological factors are important . the integration of the sad model can play a crucial role in achieving these objectives .
evidence is needed to demonstrate that the integration of art dialogues could include beneficial effects for the spectator 's perception of psychological and physiological health .
several studies show that art dialogues , with patients living in a block of specially designed flats , proved to be a way to stimulate communication [ 15 ] .
the meaning of aesthetics has been formulated by ancient philosophers such as aristoteles and is to be found in more modern research [ 715 ] .
painting , drama , dance , and music were obvious parts of everyday life and were regarded as healing for the body and mind .
art is timeless , and artistic expression has been in existence throughout mankind 's history .
it has aesthetic value , and its crucial purpose is to provide aesthetic experience and to encourage creativity in the viewer .
studies about how to use works of art has shown positive learning effects in nurse education .
the studies are based on the thinking that the way the students see things is affected by what they know , pointing at the relation between what the paintings represent and the students ' knowledge .
the painter 's way of seeing is presented in a painting , and the students ' perception or appreciation of the painting depends upon the painter 's way of seeing as well as the students ' experiences .
decoding nonverbal communication via works of art was a valuable tool additional to theoretical knowledge in order to prepare student nurses for their profession [ 16 , 17 ] .
edward munch 's painting the sick girl stimulated student nurses to engage in learning about empathy .
a control group was used to control for the effects of the visual art dialogues .
art dialogues at a museum were used in order to learn about interpersonal relations . the result based on three steps , observation , conceptualisation , and reflection , shows that student nurses became aware of interpersonal relations in works of art that communicate a broad spectrum of human experiences and thoughts [ 1922 ] .
works of art proved to increase learning outcomes when added to theoretical knowledge when teaching nursing care [ 2326 ] .
art is important in the empowerment process , and effects are found on leaders and coworkers in an art - based leadership development program .
the meaning of aesthetics for physical and psychological health as it has been described by ancient philosophers is to be found in the research of today .
for instance , aesthetic forms of expression for elderly individuals can mean discovering , preserving , or developing possibilities for a meaningful life .
several controlled intervention studies [ 19 , 31 ] describe beneficial effects in elderly individuals ' health . dialogues generated by reproductions of works of well - known artists had a positive impact on elderly individuals ' perceptions of their life situation and social interaction compared to a control group in which dialogues were about events of the day and the elderly individuals ' hobbies and interests . in a survey of living conditions ,
the results showed that attendance at cultural events , which included visiting museums , theatres or concerts , reading books , and singing in a choir , had a positive influence on survival rates .
he viewed aesthetic experiences and peak experiences , as particular kinds of experience , and an interaction between a human being and some aspects of the environment .
reflecting on an experience after its occurrence according to dewey is neither emotional nor intellectual alone ; it is an intensified form of an ordinary experience that belongs not only to the museums , but also to general experiences that culminate in aesthetic experience .
he also spoke of aesthetic peak experiences as moments of joy and temporary loss of time and self - awareness .
for instance , individuals could feel a day passing as if it were only a few minutes .
in such moments , reality is perceived as good and desirable , and the experience could be so valuable as to make life valuable .
there are many beneficial after effects of aesthetic peak experiences : individuals ' views of themselves , others , and the world that might be changed in a healthy direction .
the program included a verbal - visual procedure , characterized by dialogues based on the impressions generated from paintings , experienced - based and allowed spectators to express issues of individual value .
there is a need to further develop knowledge from previous research about visual art communication .
looking at a work of art and into the reality of other times , places , and people is to connect the past and the present and to integrate pieces of experience into a whole .
the question to be answered in the present study is whether the sad program has positive communication aspects .
the population studied was men and women with no formal education in art but interested in art and visiting art galleries . during a 1-hour session ,
the group was exposed to guided dialogues generated from the impression of the works of art .
the gallery was situated outside a city and has a view over water , hills , and flowers .
method used to collect data was accidental sampling , a sample of convenience , the most readily available persons . in the present study , it meant that participants were recruited via two galleries from their mailing lists and from persons who worked at a public department .
participants who were interested to participate were invited to a meeting to get information of the study . at this meeting
the project leader and organizers presented themselves , the aim , and procedure of the project .
participants were requested to describe , in their own words , the meaning of looking at and discussing paintings at a visual art gallery .
data was collected by questions to be answered by participants during the art intervention period : the meaning of looking at and discussing paintings in structured form at a visual art gallery , the meaning of music , reading , movie , and theater in life , the meaning of gallery visits with structured dialogues compared to gallery visits without structured dialogues , two month after the last art intervention meeting participants answered the following questions . which art form
do you prefer ? how should this art form be developed in order to reach many people ? why is the art form you prefer important for you ?
a new copy was sent in between the gallery visits that took place every second week ( n = 5 ) .
participants were asked to write down what comes to their mind when looking at the copy and send their reflections to the project leader .
data was analyzed in three steps : create a first impression of the interview , find the underlying message in the statements representing different dimensions , and formulate categories by reading text repeatedly to get an understanding behind the words .
the starting point for the analysis is qualitative , which means that the researcher is open to the text and does not make use of any theory or preconceived ideas in order to understand the text . in this study ,
a qualitative analysis of the semistructured feedback form was performed in several steps using the analytical technique [ 3335 ] .
a close examination of the data was conducted and compared for both similarities and differences .
each of the written accounts was read several times in order to grasp the content .
secondly , each account was studied to qualitatively identify different comments which together comprise the total account .
each comment was considered as a unit of analysis and defined as an utterance that provided new information about the participants ' impressions and opinions .
questions were asked about the phenomena as reflected in the data and reviewed for emerging themes and were categorized , coded , and counted .
even so , the researcher 's cultural and linguistic understanding of the phenomenon was the prerequisite for coming to an understanding of the participants ' accounts .
there can be no validity without reliability , thus demonstrating that validity is sufficient to establish reliability .
the term dependability is used in qualitative research , which closely corresponds to the notion of reliability in quantitative research . in the present study
this aspect is considered to mean that reliability is a consequence of validity . in the present study ,
credibility is ensured by accurately describing and identifying those participating , with dependability relying on credibility .
a qualitative research study that establishes credibility will also be dependable . in the present study ,
dependability was assured by following a clear research procedure and discussing decisions taken about theoretical choices with a research colleague .
the analyses were used to ensure that the meaning units in a category were not only derived from one semistructured formula . by doing this , it was possible to obtain consistency from the categories .
although the categories were consistent and valid , all the aspects of the material were not clearly displayed since the aim of describing the meaning of the sad model is a complex procedure .
it is the participants alone who decide which of the paintings they choose to look at and to talk about .
the art dialogues , generated from paintings , focus on the spectators own resources and what they see in the painting .
the exhibition constitutes of paintings , dance suits , and sculptures in papier - mch .
if they wanted , they could be inspired by following request : describe the visual art object , what it represents , colour and forms !
pretend you are the artist and know all about it , what does it brings to your mind , do you want to change something in the painting !
the artist gave a description of her thoughts when participants asked her , but pointed out that there is no explicit meaning of the painting .
this model is based on previous research [ 3 , 18 , 24 ] . between the five meetings , three times ,
participants were asked to reflect over a painting sent as a mail and respond to the project leader via mail .
the choice of paintings was be based on the knowledge that patterns are judged interesting when they contain information that can not be absorbed immediately but seem likely to be absorbed relatively quickly through perceptual and intellectual efforts .
complexity , ambiguity , and variability are associated with a high degree of uncertainty , novelty , and surprise with high information content .
it is important that the information content and the uncertainty in a visual art object is neither too low or too high but in balance with a person 's ability to perceive it .
therefore , the selection of visual art objects must be made with care , in collaboration with the person who looks at it [ 3840 ] .
the rules were followed regarding the participants receiving the usual assurance about anonymity , confidentiality , and the right to withdraw at any point without prejudice .
comments are directly quoted , while always ensuring that the speaker is not identified . from an ethical perspective , the qualities as judged by the declaration of helsinki are that the research design and the need in society for such a project are deemed to be of importance .
an ethical issue that could arise from participants in the present study was that participants were in a state of dependence in relation to the leader who was in charge of the gallery as well as has made the paintings .
however , participants were not asked to give opinions about the paintings aesthetical or formal value . in addition , the collected data was sent to the leader researcher anonymously .
the purpose and procedure were carefully explained to the participants , who were assured of confidentiality .
an ethical issue that could arise from the participants was that they were in a state of dependence in relation to the leader in charge of the gallery , particularly with concern to a question in which the participants were requested to describe the meaning of the structured art dialogues .
the results constitute of four pats based on questions to be answered by participants in written form .
the meaning of looking at and discussing paintings in structured form at a visual art gallery .
reflections two months after the study were finished ; which art form do you prefer ? how should this art form be developed in order to reach many people ?
the art form you prefer has your preferences changed during the art dialogues ?
based on question 1
participants
were requested to describe , in their own words , the meaning of looking at and discussing paintings .
participants were requested to describe , in their own words , the meaning of looking at and discussing paintings .
participants were requested to describe , in their own words , the meaning of looking at and discussing paintings .
raise association
the coffee cup classical design makes me remember .
it is really nice to discover details of old furniture from early days .
the painting show the precision of people forgotten long ago .
i have never thought of since i was four or five years of age .
it makes me remember a stable an accident riding about horses .
it is really nice to discover details of old furniture from early days .
the painting show the precision of people forgotten long ago .
the painting makes me remember i have never thought of since i was four or five years of age .
it makes me remember a stable an accident riding about horses .
it is really nice to discover details of old furniture from early days .
the painting show the precision of people forgotten long ago .
i have never thought of since i was four or five years of age .
it makes me remember a stable an accident riding about horses .
when i saw painting fishing with , associated to hitchhiking when very young .
door - openers
in order to have some help makes the conversation much easier .
i like this way to get close to the painting is a way to my inner life .
i assume i am not satisfied want to know what means the trancelike figure
i like some help the painting is a link to my inner life another person
i do not use to talk much the painting is for me a good help makes me comfortable to start a conversation .
i like this way to get close to the painting is a way to my inner life .
i assume i am not satisfied want to know what means the trancelike figure it is something to discuss .
i like some help the painting is a link to my inner life another person i can relate to .
i do not use to talk much the painting is for me a good help makes me comfortable to start a conversation .
i like this way to get close to the painting is a way to my inner life .
i assume i am not satisfied want to know what means the trancelike figure it is something to discuss . i like some help the painting is a link to my inner life another person
i do not use to talk much the painting is for me a good help makes me comfortable to start a conversation .
when i talk about a painting i communicate my feelings a help to concentrate .
i do not take for granted experience attendance presence and reality .
you are totally fascinated time goes by truly fast absorbed of the painting the dialogue force or help you to concentrate .
when i talk about a painting i communicate my feelings a help to concentrate .
i do not take for granted experience attendance presence and reality .
time goes by truly fast absorbed of the painting the dialogue force or help you to concentrate .
when i talk about a painting i communicate my feelings a help to concentrate .
i do not take for granted experience attendance presence and reality .
you are totally fascinated time goes by truly fast absorbed of the painting the dialogue force or help you to concentrate .
based on question 2
participants were asked to respond to the question ; what meaning has music , books , movies , theaters , museums in your life ? the results are presented as percentage of participants ( n = 20 ) because participants replied to this question in one or two words . therefore , the results are presented in percentage as to get a clear picture of the result .
78% of the participants answered : makes me happy , gives energy , gives inspiration .
22% of the participants answered : makes me harmonious , gives peace , open new windows .
participants were asked to respond to the question ; what meaning has music , books , movies , theaters , museums in your life ? the results are presented as percentage of participants ( n = 20 ) because participants replied to this question in one or two words .
therefore , the results are presented in percentage as to get a clear picture of the result .
participants were asked to respond to the question ; what meaning has music , books , movies , theaters , museums in your life ? the results are presented as percentage of participants ( n = 20 ) because participants replied to this question in one or two words .
therefore , the results are presented in percentage as to get a clear picture of the result .
78% of the participants answered : makes me happy , gives energy , gives inspiration .
22% of the participants answered : makes me harmonious , gives peace , open new windows .
based on question 3
the meaning of gallery visits with structured dialogues compared to gallery visits without structured dialogues .
52% of the participants answered : the dialogue increases inspiration , the dialogue makes you involved , you learn from the dialogue , the dialogue stimulates curiosity .
48% of the participants answered : the dialogue starts thoughts , the dialogue makes you expectant , and the dialogue is thrilling .
the meaning of gallery visits with structured dialogues compared to gallery visits without structured dialogues .
the meaning of gallery visits with structured dialogues compared to gallery visits without structured dialogues .
52% of the participants answered : the dialogue increases inspiration , the dialogue makes you involved , you learn from the dialogue , the dialogue stimulates curiosity .
48% of the participants answered : the dialogue starts thoughts , the dialogue makes you expectant , and the dialogue is thrilling .
based on question 4a questionnaire with four questions was used for reflections two months after the study was finished .
which art form do you prefer?how should this art form be developed in order to reach many people?why is the art form you prefer important for you?the art form you prefer has your preferences changed during the art dialogues ?
a questionnaire with four questions was used for reflections two months after the study was finished . which art form
do you prefer?how should this art form be developed in order to reach many people?why is the art form you prefer important for you?the art form you prefer has your preferences changed during the art dialogues ?
which art form do you prefer ? how should this art form be developed in order to reach many people ? why is the art form you prefer important for you ?
the art form you prefer has your preferences changed during the art dialogues ?
which art form
different art forms are needed a resource put into words thinking
sometimes i need to listen to music it depends on my frame of mind .
sometimes i need to listen to music it depends on my frame of mind .
different art forms are needed a resource put into words thinking
sometimes i need a book sometimes i need to listen to music it depends on my frame of mind .
how should the art form you prefer be developed in order to reach many people
hospital personnel start art dialogues with patients . different perspective economically , politically , and culturally must be considered .
you have to be offered opportunities early in life in order to appreciate
learn to express oneself find your own way it might be difficult if you do not start early in life .. start gallery for amateurs in nursing care .
hospital personnel start art dialogues with patients . different perspective economically , politically , and culturally must be considered .
you have to be offered opportunities early in life in order to appreciate
learn to express oneself find your own way it might be difficult if you do not start early in life .. start gallery for amateurs in nursing care .
hospital personnel start art dialogues with patients . different perspective economically , politically , and culturally must be considered .
you have to be offered opportunities early in life in order to appreciate
learn to express oneself find your own way it might be difficult if you do not start early in life . .
you learn new things about yourself about the society . a way to loosen up a way to be alert and aware .
the art form you prefer has your preferences changed during the art dialogues ?
you learn new things about yourself about the society . a way to loosen up a way to be alert and aware .
the art form you prefer has your preferences changed during the art dialogues ?
you learn new things about yourself about the society . a way to loosen up a way to be alert and aware .
the art form you prefer has your preferences changed during the art dialogues ?
the aim of the study was to investigate the value of adding structured art dialogues in small group setting .
the art dialogue starts with observation . participants carefully observe the paintings to be able to choose one painting they prefer .
then they were asked to describe this painting according to form , colour , and representation .
then in the interpretation phase , the participants were asked to use imagination . in the reflection phase
it was considered important that the paintings the participants could choose among were in balance concerning complexity and level of representativeness with the onlooker 's ability to perceive them [ 2 , 4 , 38 , 39 ] .
the main results are that the participants expressed positive value effects of an art dialogue structure .
this can be seen in light of the communication process as a complex experience of personal experience . in the present study
i do not use to talk much the painting is for me a good help makes me remember and it starts conversation .
it is expressed in words like makes me happy , gives energy , and gives inspiration .
similar findings could be found in a study about older adults who express the importance of art in their life .
it is expressed in words like the painting shows the precision of people forgotten long ago and
i have never thought of since i was four or five years of age .
i like this way to get close to the painting is a way to my inner life and it is easy to open a conversation leads to further conversation
a further result in the present study is that the respondents expressed mentally presence when engaged in the art dialogues .
i was aware of awake and you are totally fascinated
time goes by truly fast absorbed of the painting the dialogue force or help you to concentrate .
similar thinking is expressed in several studies [ 10 , 11 , 40 , 42 , 43 ] . to share emotions and to discuss visual art play an important role for a successful gallery visit .
supporting the spectator could predict a new quality based on the content of the painting . to the best of the authors ' knowledge , qualitative semistructured questionnaires were the best approach to answer the research question .
it was obvious that the respondents found it difficult to put into words their experiences of art dialogues .
however , when the respondents were told that they can not write anything that is wrong , they experience a release
. a weakness in the present study could be that objective data was not collected .
nonetheless , the main focus of the study has been the participants ' perception and points of view about adding structured dialogues to a gallery visit .
still the problem with accidental sampling is that available subjects might be atypical of the population with regard to the variables being measured .
a bias factor that could not be excluded is that the participants could feel forced to give positive opinions about the importance of art dialogues , because it was the artist who assisted participants in the art dialogues .
in addition , they placed their responses in an envelope that was sent to the researcher .
the present study supported the view that meaningful art stimulation , related to a person 's experiences and expectations , will be of importance in peoples ' life .
it is to be hoped that the art dialogues ' program could be implemented in hospital settings as a fruitful working tool for health care professionals .
we have to take into consideration the importance a visual art dialogue can have for health professionals and patients .
the approach in this study demonstrates one way of using visual art as a means of communication .
however , more data are needed in order to explore the means by which art communication can be successful . | objectives . given that hospitals have environmental enrichment with paintings and visual art arrangement
, it would be meaningful to develop and document how hospital art could be used by health professionals .
methods .
the study was undertaken at an art site in sweden . during 1-hour sessions ,
participants ( n = 20 ) get together in an art gallery every second week five times . results . according to the participants a new value was perceived . from qualitative analyses , three themes appear : raise association , mentally present , and door - opener .
in addition 72% of the participants reported makes me happy and gives energy and inspiration , and 52% reported that dialogues increase inspiration , make you involved , and stimulate curiosity . conclusion .
the present study supported the view that visual art dialogue could be used by health care professionals in a structured manner and that meaningful art stimulation , related to a person 's experiences , could be of importance for the patients . implementing art dialogues in hospital settings could be a fruitful working tool for nurses , a complementary manner of patient communication . |
the association between dietary fat and risk of cancer has been extensively investigated , and the composition of polyunsaturated fatty acids ( pufa ) in diet seems to be of particular importance . however , the effects of single dietary n-3 and n-6 pufa , and the ratio n-3/n-6 pufa are not completely clear .
the majority of case - control studies seem to support a protective role of dietary n-3 pufa and n-3/n-6 pufa ratio [ 24 ] , but these associations have been confirmed by only one cohort study , and have been contradicted or not found by several cohort studies [ 68 ] .
studies on serum and erythrocyte membrane fatty acid composition , regarded as biomarkers for fatty acid intake , mainly support a protective role for the very long - chained n-3 pufa docosahexaenoic acid ( dha ) [ 811 ] .
abnormalities in plasma pufa composition may also be interpreted as metabolic changes in crc patients .
dietary and biomarker studies have not established the role of n-6 pufa in crc . based on changes in n-3 and n-6 pufa expression in colorectal tumours , compared to normal mucosal tissue [ 13 , 14 ] , also found at early stages of adenomas , it seems obvious that patients with crc have an altered pufa metabolism .
literature on crc tumour pufa pattern is sparse , and previous studies have not concluded on which particular pufas are present in diseased and normal mucosa [ 13 , 14 ] . however , pufa pattern in normal mucosal tissue seems to be similar in crc patients and healthy subjects .
this indicates that the changes in mucosal fatty acid pattern are tumour and normal tissue specific in general crc patients
. the younger crc patients may be more genetically predisposed ; their tumour might be expected to be more aggressive and environmental factors relatively less pronounced in the etiology of the disease , compared to older patients .
genetic predisposition is known in patients with familial adenomatous polyposis ( fap ) , who may have characteristics more similar to young crc patients .
our previous study in fap patients showed increased concentrations of arachidonic acid ( aa ) and dha , and decreased concentrations of linoleic acid ( la ) and -linolenic acid ( ala ) in plasma phospholipids ( pl ) , opposite to the majority of findings of protective effect of dha against development of colorectal adenomas [ 911 , 17 ] .
we therefore hypothesize that pufa concentration in plasma phospholipid does not reflect dietary pufa in young crc patients .
we further hypothesize that pufa composition differs between crc tumour tissue and normal colonic mucosal biopsies , thereby investigating if the fatty acid pattern characteristic for fap patients could be observed in the colorectum of crc patients .
we also wanted to study whether dietary pufa intake or concentration of pufa in plasma pl , tumour , or normal mucosa were associated with cancer stage ( duke 's stage ) .
eighty - two patients were recruited from seven hospitals in the south - eastern region of norway .
exclusion criterion was known familial syndromes affecting crc risk including hereditary non - polyposis colorectal cancer ( hnpcc ) and fap .
the frozen samples were sent on dry ice to vitas as , oslo , norway , where they were stored at 20c until analyses . fatty acid contribution in plasma phospholipid fraction ( pl ) was quantitatively determined as follows : plasma samples were thawed overnight at 4c and vortexed for 5 sec .
dichloromethane in methanol was added to plasma and the internal standard ( 1,2 diheptadecaonyl - sn - glycero-3-phosphatidylcholine ) . after shaking and centrifugation ,
polar lipids were washed out with dichloromethane / isopropanol and methyl tert - butyl ether ( mtbe)/formic acid .
after evaporation to dryness in a vacuum centrifuge , phospholipids were transmethylated by sodium methoxide , and fatty acid methyl esters ( fames ) were extracted to hexane before gas - chromatographic ( gc ) analysis .
the gc analysis was performed on a 7683b gc with a split / splitless injector , a 7683b automatic liquid sampler , and flame ionization detection ( agilent technologies , palo alto , ca , usa ) . separations were performed on a 30 m sp-2380 column ( supelco , sigma - aldrich , st .
tumour and normal mucosa tissue samples , at least 2 1 0.5 cm in size , were collected immediately after resection of the specimen , prepared with rna - later , transported , and stored dry in 80c until analysis .
the normal mucosa sample was taken from a normal appearing part of the resected specimen , at least 20 cm from the cancer .
the frozen samples were sent on dry ice to vitas as , oslo , norway , where tissue fatty acid contribution was determined as follows : approximately 10 mg tissue was directly methylated with 3n meoh hcl , first 30 minutes at 70c on an ultrasonic bath , and later at 80c on a thermoblock with 500 rpm .
fames were extracted with hexane , and the samples were subsequently neutralized with koh in water . after mixing and centrifuging
the patients were contacted postoperatively by telephone and invited to give dietary and lifestyle data .
dietary intake was assessed by a validated self - filled food - frequency questionnaire ( ffq ) , designed to cover as much of the total diet as possible .
questions were related to habitual frequency of consumption and the amount of foods eaten during the one - year period prior to crc diagnosis .
dietary supplements , such as cod liver oil , fish oil capsules , and vitamin and mineral supplements , were included .
the ffq was mailed to the participants and filled in at home . after returning of the questionnaire by mail ,
the participants were contacted by a dietitian by telephone , and filling of the ffq was checked .
dietary intakes were calculated by using a database and a software system developed at the department of nutrition , university of oslo ( kostberegningssystem , version 3.2 ; university of oslo , oslo , norway ) . in the previously developed lifestyle questionnaire , participants were asked to describe their smoking status by detailed questions on current and lifetime smoking status .
participants were asked to assess their last weight before crc diagnosis as well as nonvigorous and vigorous physical activity ( minimum 20 min at the time ) .
the alternative frequencies of activity were : never , less than once / week , 1 - 2 times / week , 3 - 4 times / week , 57 times / week , and more than 7 times / week .
the participants were also asked to state their weekly hours of occupational activity prior to crc diagnosis , and possible changes in physical activity and dietary habits after the diagnosis .
the study protocol was approved by the norwegian health authorities and the regional ethics committee .
we tested differences in fatty acid concentrations between tumour and normal mucosa by paired , non - parametric wilcoxon signed ranks test , and differences in categorical variables between subgroups by chi - square statistics .
we also tested correlations between dietary and plasma pl fatty acids , and between pufa in plasma pl and normal mucosa and tumour tissue in analysis stratifying by bmi ( < 25 and 25 kg / m ) .
we conducted the statistical analysis using software spss 15.0 for windows ( spss inc . ,
a total of 69 patients provided sufficient dietary data , whereas 79 patients had data on plasma pl . totally 65 crc patients with median age of 47 years ( range 2754 years ) , and median bmi of 24.8 kg / m ( range 18.443.2
kg / m ) , had data on fatty acid composition in diet and plasma pl .
altogether 32 patients had additional data on fatty acid composition in tumour and normal colonic mucosal tissue .
forty - eight percent of the subjects were overweight or obese ( 25 kg / m ) , whereas six percent of the patients had low bmi ( < 20 kg / m ) .
thirteen percent of the subjects reported themselves as current daily smokers , whereas 37 percent reported never having smoked .
first or second degree family history of crc in 14 percent of the patients was confirmed by the cancer registry of norway .
the self - reported physical activity level was not associated with dietary intake of energy or fat , or bmi ( not shown ) .
mean dietary intake of total and saturated fat was somewhat higher than in the nordic nutrition recommendations .
intakes of total and long - chained marine n-3 pufa were in line with the recommendations ( table 2 ) .
dietary dha intake and the sum of epa and dha intake correlated positively with the respective concentrations in plasma pl ( r = 0.42 , p = 0.001 and r = 0.36 , p = 0.003 , resp . )
. other n-3 or n-6 pufa did not show correlation between diet and plasma pl , but the ratio of n-3/n-6 pufa showed a correlation between diet and plasma pl ( r = 0.29 , p = 0.02 ) ( table 2 ) .
the correlations did not noticeable differ between lean and overweight patients ( not shown ) .
when separating the crc patients into low and high dietary epa + dha intake at a median of 0.82 g / day , the patients with intake above the median had higher plasma pl concentration of dha and n-3/n-6 pufa ratio ( p = 0.004 and p = 0.006 , resp . ) , and borderline significantly lower plasma pl concentration of la + aa and ratio of aa / epa ( p = 0.05 for both ) ( table 3 ) .
median concentrations of all individual fatty acids of interest differed significantly between normal mucosa and tumour tissue ( table 4 ) .
median concentrations of all long - chained n-3 and n-6 pufa ( c20 - 22 ) were higher in tumours than normal biopsies , whereas concentrations of the c18-chained pufa la and ala were lower in tumour tissue than normal mucosa .
aa and dha were higher in tumours than normal biopsies ( 7.5 versus 3.5 g/100 g , p = 0.001 , and 2.2 versus 1.3 g/100 g , p < 0.001 , resp . ) .
the ratio n-3/n-6 pufa , but also the ratio aa / epa were higher in the tumour than normal tissue ( 0.15 versus 0.13 , p < 0.001 and 12.5 versus 9.7 , p = 0.03 , resp . ) ( table 4 ) .
there was a significant correlation between plasma pl concentrations of epa and dha ( weight% ) and the concentrations of epa and dha in normal mucosa and tumour tissues .
these correlations existed both for epa and dha separately , and for the sum of these ( table 5 ) .
also the ratio n-3/n-6 pufa in normal mucosa and tumour tissue significantly correlated with plasma pl concentration of epa + dha .
the significant correlation between plasma pl concentration of epa + dha , and aa concentration in normal mucosa ( r = 0.43 , p = 0.02 ) remained significant only in overweight patients ( r = 0.69 , p = 0.005 ) when stratifying by bmi groups .
plasma pl concentration of la + aa ( weight% ) correlated positively with la concentration in normal mucosa tissue .
there were no other correlations between plasma pl concentration of la + aa , and tissue pufa concentrations , but the ratio of n-3/n-6 pufa in normal mucosa was significantly inversely correlated with plasma pl concentration of la + aa ( table 5 ) .
median dietary intake of dha was higher in crc patients with severe duke 's stage ( c + d ) as compared to patients with less severe duke 's stage ( a + b ) ( 0.56 versus 0.45 g / d , p = 0.02 ) ( table 6 ) . further , dietary ratio of n-3/n-6 pufa was higher in patients with duke 's stage c + d compared to a + b ( 0.21 versus 0.18 , p = 0.007 )
. there were no significant differences in dietary aa content or plasma pl concentrations of any n-3 or n-6 pufa between the duke 's stage groups ( table 6 ) .
there was no difference between the duke 's stage groups in any of pufa concentrations or ratios in tumour and normal mucosal tissue ( not shown ) .
in the present study of young crc patients , we found that dietary intake of total pufa and marine n-3 fatty acids epa and dha were according to national dietary recommendations .
dietary dha intake was in this patient population related to its concentration in plasma pl , tumour tissue , and normal mucosa .
dietary intake of single n-6 pufa , la and aa did not correlate with its concentration in plasma pl , tumour tissue or normal mucosa . on the other hand ,
high dietary intake of epa and dha was reflected as high concentrations of these fatty acids and a high ratio of n-3/n-6 pufa in plasma and tissues .
concentrations of n-3 and n-6 pufa with chain length c20 - 22 ( aa , epa and dha ) and the ratio of n-3/n-6 pufa were higher in tumour tissue than normal mucosa , whereas concentrations of pufa with chain length c18 ( la and ala ) were higher in normal mucosa . surprisingly , dietary dha intake was positively related to cancer severity measured by duke 's stage .
the present results suggest that fatty acid metabolism is altered in crc patients , as indicated by earlier studies .
first , we did not find correlation between dietary intakes of single n-6 pufa and plasma pl concentrations of these in crc patients .
the absence of correlation for la between diet and plasma pl agrees with an earlier similar finding in fap patients , but disagrees with large studies in average , diverse adult population , which have demonstrated a significant positive correlation between la concentration in plasma pl ( weight% ) and habitual diet assessed by ffq [ 21 , 22 ] .
another sign of abnormal la metabolism in crc in the present study was that concentration of la in plasma pl significantly correlated with la concentration in normal mucosal tissue , but not in tumour tissue .
this indicates an altered incorporation of la from plasma pl into tumour tissue , or increased elongation of la into aa in tumours . as a contrast
, there were high correlations between intake levels , plasma pl and tumour and normal mucosal tissue concentrations for epa and dha in the present crc patient population . such high correlations between intake and biomarkers of these external pufa are found in average population [ 21 , 22 ] and were expected also for la .
n-3 pufa concentrations in plasma pl were reflected in their concentrations in both normal mucosa and tumour tissue in the present study .
an unexplainable finding was that n-3 pufa concentration in plasma pl correlated also with aa concentration in normal mucosa , and only in overweight and not in lean patients .
the second major finding on altered fat metabolism in crc patients was that pufa concentrations of crc tumour tissue differed from non - diseased mucosal tissue in the present patient group ; aa , epa , and dha were more abundant in tumour tissue than in normal colonic mucosa .
this reflects the pufa pattern in plasma pl found earlier in fap patients as compared to control subjects .
similar results on increased aa and dha concentrations in human crc tumours and a higher concentration of aa in rat tumour tissue have been found .
in contrast , the opposite has also been found ; lower aa concentration in phospholipids extracted from human colon cancer cells compared to normal mucosa cells , non - different concentrations of aa and dha , and lower concentration of epa in human diseased versus normal mucosa .
the ratio n-3/n-6 pufa in plasma pl and tumour tissue was in the present study correlated to dietary intake of epa and dha and was higher in tumour tissue than in normal mucosa .
this suggests that epa and dha are incorporated from diet into plasma and tissues in crc patients , but that these are particularly accumulated in tumour tissue .
the lower concentrations of ala in tumour than normal mucosal tissue may also suggest an increased elongation of ala into epa and dha in tumours . the markedly increased aa concentration and lower la concentration
concentrations of all other measured fatty acids were also significantly different between tumour tissue and normal mucosa .
interpretation of differences in sfa and mufa concentrations is difficult and may reflect the differences in pufa concentrations .
the third and most unexplainable finding of altered pufa metabolism in the present study was that patients with the most advanced cancer stage reported highest dietary intake of dha , and ratio of dietary n-3/n-6 pufa .
however , this difference in intake between duke 's stage groups a + b and c + d was not reflected in plasma pl .
one reasonable explanation might be overreporting of dietary marine n-3 pufa intake among those with the most severe diagnosis .
the ffq was filled by the patients up to four weeks after the crc diagnosis .
dietary habits may have changed after the diagnosis , biasing reporting of average diet before the diagnosis . a possible true relationship between higher dietary intake of dha and crc severity
would be unexpected in the light of the major evidence for a protecting effect of n-3 pufa in colorectal carcinogenesis [ 25 , 26 ] .
animal and cell line experiments suggest that n-3 pufa on the contrary may reduce colorectal tumour formation and suppress aa - induced proliferation in colon carcinoma cells .
there also is a plausible pathway for the anticarcinogenic effect of n-3 pufa through inhibiting pge2 synthesis and consequently reducing cox-2 expression [ 29 , 30 ] , an important step in colorectal carcinogenesis .
further , there is evidence that dietary n-3 pufa intake protects against inflammation in cancer patients by an effect on cox-2 levels [ 31 , 32 ] .
a possible carcinogenic effect of dietary epa and dha might relate to proinflammatory activity of these highly oxidizable fatty acids .
high - dose n-3 pufa intervention ( 2.54.8 g epa + dha per day ) in other patient groups has resulted in increased concentrations of soluble inflammatory markers of endothelial function [ 34 , 35 ] . these , as well as other inflammatory markers have been related to crc development and increasing duke 's stage [ 3638 ] .
the median dietary intake of epa and dha in the present patient group was , however , according to national recommendations , and only two patients reported intake levels above 2.0 g per day . in spite of an average intake of fatty acids as recorded by the questionnaires ,
overweight was prevalent ( 48% of the patients with bmi 25 kg / m ) .
malignancy at younger age may indicate genetic involvement , but also a direct relationship between overweight and colorectal neoplasia could be possible .
nevertheless , we did not observe higher prevalence of overweight or obesity in the group with higher duke 's stage .
future long term studies are needed to confirm a possible association between intake of high - dose n-3 pufa intake and duke 's stage .
the study would also have been strengthened by additionally analyzing fatty acid patterns in adenomas , since colorectal neoplasia develops over many years and the metabolic situation in cancerous tissue is different from that in adenomas .
further , it is unclear to what extent fatty acid intake right before the diagnosis , as assessed in the present study , is the critical period of intake with regard to tumorigenesis .
the most optimal study design might therefore include dietary intake , plasma and tissue samples from patients with colorectal adenomas , and crc patients and healthy controls .
the present study showed that metabolism of n-6 and n-3 pufa was altered in young crc patients .
dietary la did not correlate with its concentration in plasma pl and normal tissue , indicating an increased elongation of la into aa in tumour tissue .
the higher concentrations of aa , epa and dha , and ratio of n-3/n-6 pufa in colorectal tumours than in normal mucosal tissue warrants further investigations .
we suggest that future prospective studies address the possible relation between dietary intake of n-3 pufa and duke 's stage in crc in comparison to normal mucosa and adenomas , both among young and old patients . | fatty acid metabolism is altered in colorectal cancer ( crc ) .
we aimed to investigate incorporation of dietary n-6 and n-3 polyunsaturated fatty acids ( pufas ) into plasma phospholipids ( pls ) , tumour tissue , and normal mucosa in young crc patients .
we also aimed to study differences in pufa composition between tumour and normal mucosa , and pufa status associated with cancer stage .
sixty - five crc patients younger than 55 years were included in a multicenter study .
we assessed dietary fatty acid composition by food - frequency questionnaire .
fatty acid composition in plasma pl ( n = 65 ) and tumour and normal colonic biopsies ( n = 32 ) were analysed by gas chromatography .
we observed a significant correlation for docosahexaenoic acid ( dha ) between dietary intake and concentration in plasma pl ( weight% ) ( r = 0.42 ; p = 0.001 ) , but not for any n-6 pufa .
tissue concentrations of arachidonic acid , eicosapentaenoic acid , and dha ( weight% ) were 1.72.5 times higher in tumour than normal mucosa ( p 0.001 ) .
concentrations of n-3 and n-6 pufa in plasma pl and tissues were not related to duke 's stage , although patients with more severe cancer stage reported higher intake of n-3 pufa . in conclusion , we found accumulation of the long - chained n-3 and n-6 pufa in tumour tissue in young crc patients . |
his medical history revealed hospitalization for heart failure as well as treatment for arterial hypertension and permanent atrial fibrillation .
diagnosis was by transesophageal echocardiography showing a linear structure dividing the left atrium in two chambers ( figure 1 ) .
pulmonary veins drained into the postero - superior chamber and the mitral valve and the left atrial appendage were located in the antero - inferior chamber .
consequently , the diagnosis of cor triatriatum sinistrum class a according to the lam classification was made .
furthermore , the diagnosis of a calcified bicuspid aortic valve with moderate stenosis was established corresponding to a sievers type classification of 1 , l / r meaning one raphe between a fused left and right coronary cusp .
a classical combination of a sinus of valsalva and ascending aortic dilatation was seen during ct angiography ( figure 2 & 3 ) .
heart failure therapy was optimized , symptoms improved and he is currently seen on a regular basis in our outpatient clinic .
the combination with bicuspid aortic valve disease is even rarer , as is late presentation in life as in our patient , and a mere single digit report in the literature was available . the median age in a recently published series of the mayo clinic was 19 years .
obviously , functional obstruction of the membrane is moderate and , therefore , physiologically compensated . by the onset of atrial fibrillation , it might have been that symptoms occurred .
however , this was not connected to a congenital defect , but due to the onset of atrial fibrillation per se .
regarding diagnostics , transthoracic and transesophageal echocardiography have obviously become the treatment modalities of first choice to establish the correct diagnosis .
furthermore , the rare association with a bicuspid aortic valve was made . in our patient ,
additional ct angiography further revealed ectasia of the sinus of valsalva as well as the ascending aorta .
these are most likely the very aspects making this case report unique , as we were not able to identify a single case report where a clear categorization of lam classification and loeffler groups , as sievers classification of bicuspidity , was established .
furthermore , this patient is one of the few who seems to do well with modification of heart failure therapy as well as rate control of atrial fibrillation .
summarizing , the combination of cor triatriatum sinistrum and bicuspid aortic valve disease is a rare variation of nature .
furthermore , membranes with a larger effective orifice area might be treated conservatively in distinct clinical situations . | we presented a 73-year - old patient with a history of hospitalizations for heart failure as well as treatment for arterial hypertension and permanent atrial fibrillation and who was found to have cor triatriatum sinistrum in combination with bicuspid aortic valve .
patient refused surgical correction , but his condition improved on conservative therapy for heart failure and atrial fibrillation . |
baculoviruses are arthropod - specific viruses containing large double - stranded circular dna genomes of 80,000180,000 bp .
the progeny generation is biphasic , with two different phenotypes during virus infection : budded viruses ( bvs ) , during the initial stage of the multiplication cycle , and occlusion - derived viruses ( odvs ) , at the final stages of replication [ 1 , 2 ] . in general
, primary infection takes place in the insect midgut cells after ingestion of occlusion bodies ( obs ) . following this stage ,
systemic infection is caused by the initial bv progeny [ 3 , 4 ] . and finally , obs are produced during the last stage of the infection .
these obs comprise virions embedded in a protein matrix which protects them from the environment [ 5 , 6 ] .
baculoviruses have been used extensively in many biological applications such as protein expression systems , models of genetic regulatory networks and genome evolution , putative nonhuman viral vectors for gene delivery , and biological control agents against insect pests [ 717 ] .
the baculoviridae family is divided into four genera according to common biological and structural characteristics : alphabaculovirus , which includes lepidopteran - specific baculoviruses and is subdivided into group i or group ii based on the type of fusogenic protein , betabaculovirus , comprising lepidopteran - specific granuloviruses , gammabaculovirus , which includes hymenopteran - specific baculoviruses , and finally deltabaculovirus which , to date , comprises only cuninpv and possibly the still undescribed dipteran - specific baculoviruses [ 1 , 1820 ] .
the comparison between known genome sequences of all baculoviruses has been the source for identifying a common set of genes , the baculovirus core genes .
however , there are probably more orthologous sequences that may not be identified due to the accumulation of many mutations throughout evolution .
thus , core genes seem to be a key factor for some of the main biological functions , such as those necessary to transcribe viral late genes , produce virion structure , infect gut cells abrogate host metabolism and establish infections [ 2124 ] .
for this report , previous data as well as bioinformatic studies conducted on currently available sets of completely sequenced baculovirus genomes were taken into account and have resulted in a summary of gene content and phylogenetic analyses which validates the classification of this important viral family .
these include 41 alphabaculoviruses , 12 betabaculoviruses , 3 gammabaculoviruses , and 1 deltabaculovirus . as a first approach to perform a comparative analysis ,
the histogram revealed that many baculoviruses have about 41% of gc content although several of them have significantly higher values ( cfmnpv at 50.1% , cuninpv at 50.9% , anpenpv - l2 at 53.5% , anpenpv - z at 53.5% , lyxynpv at 53.5% , opmnpv at 55.1% , and ldmnpv at 57.5% ) .
a detailed analysis of dna content did not show a clear pattern of gc content that could be associated with each genus .
further characterization of the patterns of gene content and organization may prove useful for establishing evolutionary relationships among members of baculoviridae .
the high variability observed in the number of coding sequences becomes a key feature of viruses with large dna genomes that infect eukaryotic cells .
insertions , deletions , duplication events , and/or sequence reorganizations by recombination or transposition processes seem to be the main forces of the macroevolution in this particular kind of biological entities .
for example , the loss or gain of genetic material could provide new important abilities for colonization of new hosts , or they could improve performance within established hosts
. however , there seems to be a set of core genes whose absence would imply the loss of basic biological functions , and that could be typical of the viral family . in view of this , and considering previous reports [ 1 , 19 , 22 , 23 ] , the amount and identity of baculovirus common genes were reevaluated ( table 2 ) . as a result ,
p6.9 and desmoplakin were recognized in this work , as core proteins by using sequence analysis complementary to the standard ones ( see supplementary files available at doi:10.4061/2011/379424 ) .
the group of conserved sequences found in all baculovirus genomes is consistently estimated at about 30 shared genes , regardless of the increasing number of genomes analyzed [ 22 , 148 ] . meanwhile ,
the role or function assigned to several sequences has been renewed , according to new studies .
in particular , it has been identified that 38k ( ac98 ) gene encodes a protein which is part of the capsid structure [ 121 , 122 ] ; p33 ( ac92 ) is a sulfhydryl oxidase which could be related to the proper production of virions in the infected cell nucleus [ 123125 ] ; odv - ec43 ( ac109 ) is a structural component which would be involved in bv and odv generation ; p49 ( ac142 ) is a capsid protein important in dna processing , packaging , and capsid morphogenesis ; ac81 interacts with actin 3 in the cytoplasm but does not appear in bvs or in odvs ; odv - e18 ( ac143 ) would mediate bv production ; desmoplakin ( ac66 ) seems to be essential in releasing processes from virogenic stroma to cytoplasm ; pif-4 ( ac96 ) and pif-5 ( odv-56 , ac148 ) are odv envelope proteins with an essential role in per os infection route [ 145 , 147 ] ; ac68 may be involved in polyhedron morphogenesis
. the number and identity of shared orthologous genes in every accepted member of each genus were investigated , and the unique sequences typical of each clade as well as those shared between different phylogenetic groups were identified ( figure 2 ) .
this analysis shows that the four accepted baculovirus genera have accumulated a large number of genes during evolution .
probably , many of these sequences have been incorporated into viral genomes prior to diversification processes since they are found in members of different genera .
in contrast , other genes are unique to each genus , suggesting that they have been incorporated more recently and after diversification ( table 3 ) .
the possibility that nonshared genes found only in one genus which represent baculovirus ancestral sequences deleted in the other lineages should also be considered . in any case ,
a set of particular genes which could help in an appropriate genus taxonomy of new baculoviruses with partial sequence information were obtained from this analysis .
the study of all genes reported in the 57 completely sequenced viral genomes revealed the existence of about 895 different orfs , a set of sequences that might be called the whole baculovirus gene content .
this high number of potential coding sequences contrasts with the range of gene content among the family members , which is between 90181 genes ( alphabaculovirus : 118169 ; betabaculovirus : 116181 ; gammabaculovirus : 9093 ; deltabaculovirus : 109 ) as well as with the proportion of core genes which represents only 3% .
this curious biological feature supports the hypothesis that highlights the great importance of structural mutations in the macroevolution of viruses with large dna genomes . from this view
, the set of genes shared by all members belonging to each baculovirus genus was compared to those corresponding to the whole genus gene content ( figure 3 ) .
the analysis shows that group i alphabaculoviruses and gammabaculoviruses have a lower diversity of gene content with respect to the rest of lineages .
this information , coupled with the significant number of genome sequences obtained from group i alphabaculoviruses , suggests that this lineage of viruses would constitute the newest clade in baculovirus evolution history .
this is based on the assumption that group i alphabaculoviruses have had less time to incorporate new sequences from different sources ( host genomes , other viral genomes , bacterial genomes , etc . ) since the appearance of their common ancestor .
traditional attempts to infer relationships between baculoviruses were performed by amino acid or nucleotide sequence analyses of single genes encoding proteins such as polyhedrin / granulin ( the major component of obs ) , the envelope fusion polypeptides known as f protein and gp64 , or dna polymerase protein , among many other examples [ 149152 ] .
mostly , the evolutionary inferences were in agreement with much stronger subsequent studies based on sequence analyses derived from sets of genes with homologous sequences in all baculoviruses .
thus , these new approaches were based on the construction of common - protein - concatemers which were used to propose evolution patterns for baculoviruses . then
, the fact that a viral family consists of members who share a common pattern of genes and functions and whose proliferation cycle continuously challenges the viral viability turns it essential to take into account their higher or lesser tolerance to the molecular changes . molecular constraints regarding tolerance to changes in core genes are different from those of other genes .
therefore , core genes should be considered the most ancestral genes which may have diverged in higher or lesser degrees . according to this ,
a phylogenetic study was performed based on concatemers obtained from multiple alignments of the 31 proteins recognized in this work as core genes for the 57 available baculoviruses with sequenced genomes ( figure 4 ) .
additionally , this approach consistently separates the alphabaculoviruses into two lineages : group i and group ii . and the same can be observed when analyzing group i , where the presence of two different clades can be clearly inferred ( clade a and clade b ) .
these groupings result in accordance with previous reports [ 20 , 150 ] . in group
ii alphabaculoviruses , a clear clustering may not be identified and would not allow to suggest a subdivision .
in contrast , in the betabaculovirus genus , it is possible to propose their separation into two different clades : clade a ( xngv , heargv , psungv , spligv , agsegv , and plxygv ) , and clade b ( adorgv , phopgv , cpgv , crlegv , piragv , chocgv ) . despite the evolutionary inference based on core genes
, there was a remaining question : is the tolerance to changes in all core genes the same ? .
the answer could be reached by an individual core gene variability analysis for which studies of sequence distance for each baculovirus core gene were performed ( figure 5 ) .
the resulting order of core genes shows that pif-2 was the most conserved baculovirus ancestral sequence , whereas desmoplakin was the gene with evidence of greatest variability .
this analysis reveals that genomes can be evolutionarily constrained in different ways depending on the proteins they encode .
the gain of access to new hosts might be an important force for gene evolution . during an infection process
, the genome variants that appear with mutations introduced by errors in the replication / reparation machinery could be quickly incorporated into the virus population if the nucleotide changes offered a better biological performance when proteins were translated .
the dna helicase gene was considered as an important host range factor being , for this study , the second core sequence showing more variability .
however , other sequences like pif-2 gene would not accumulate mutations because the protein encoded might lose vital functions not necessarily associated with the nature of the host .
baculoviridae is a large family of viruses which infect and kill insect species from different orders
. the valuable applications of these viruses in several fields of life sciences encourage their constant study with the goal of understanding the molecular mechanisms involved in the generation of progeny in the appropriate cells as well as the processes by which they evolve .
the establishment of solid bases to recognize their phylogenetic relationships is necessary to facilitate the generation of new knowledge and the development of better methodologies . in view of this , many researchers have proposed and used different bioinformatic methodologies to identify genes as well as related baculoviruses .
some of them were based on gene sequences , gene content , or genome rearrangements . in this work ,
a combination of core gene sequence and gene content analyses were applied to reevaluate baculoviridae classification . to our knowledge ,
the most important fact is that this report is the first work which identifies the whole baculovirus gene content and the shared genes that are unique in different genera and subgenera .
all this information should be taken into account to group and classify new virus isolates and to propose molecular methodologies to diagnose baculoviruses based on proper gene targets according to gene variability and gene content . | the baculoviridae is a large group of insect viruses containing circular double - stranded dna genomes of 80 to 180 kbp . in this study ,
genome sequences from 57 baculoviruses were analyzed to reevaluate the number and identity of core genes and to understand the distribution of the remaining coding sequences .
thirty one core genes with orthologs in all genomes were identified along with other 895 genes differing in their degrees of representation among reported genomes .
many of these latter genes are common to well - defined lineages , whereas others are unique to one or a few of the viruses .
phylogenetic analyses based on core gene sequences and the gene composition of the genomes supported the current division of the baculoviridae into 4 genera : alphabaculovirus , betabaculovirus , gammabaculovirus , and deltabaculovirus . |
between 1990 and 2013 , the global tuberculosis ( tb ) prevalence and mortality rates decreased by 41% and 45% , respectively ( 1 ) . despite the apparent progress in tb control ,
9 million people developed tb and 1.5 million people succumbed to the disease in 2013 , reiterating that this disease is still a severe global public health challenge ( 1 ) .
the world health organization s post-2015 global tb strategy aims to reduce the 2015 worldwide tb incidence and mortality rates by 90% and 95% , respectively , by the year 2035 ( 1 ) .
the achievement of these goals is dependent on the identification of novel biomarkers and targets for which new innovations for tb diagnosis , treatment , and prevention can be elucidated .
these goals may be realized by intensifying scientific research into the interaction of the tb etiologic agent , mycobacterium tuberculosis , with its human host .
a vital precursor to host colonization and the deploying of bacterial virulence factors , such as toxins and effector proteins , is the adhesion of the pathogen to host cells .
the initial binding to host cells occurs via weak and non - specific forces that are brought about by the physicochemical properties of the host surface .
thereafter , specific and transient receptor interactions enable a stronger anchorage of the pathogen to the host surface .
lastly , specific and high - affinity attachment is achieved by the interaction of bacterial adhesins with host receptors ( 2 ) .
adhesins are monomeric or filamentous cell - surface molecules or structures that facilitate bacterial attachment to host surfaces .
this process is a pivotal precursor to bacterial invasion and colonization of the host , by limiting the clearance of the pathogen through shear stress and by activating key virulence factors that are associated with infection ( 3 ) .
furthermore , bacterial adhesion to host cells results in a manipulation of host cell signalling , which promotes the spread of the pathogen and allows for the microbe to evade the host immune response ( 3 ) .
adhesins also bind to receptors of the extracellular matrix ( ecm ) , thereby activating signal transduction cascades in the host cell .
these adhesins , termed microbial surface components recognizing adhesive matrix molecules ( mscramm ) , use receptors ( such as integrins ) to adhere to ecm molecules , including bone sialoprotein , collagens , elastin , fibronectin , glycosaminoglycans , laminin , thrombospodin , and vitronectin ( 4 ) . the ability of environmental bacteria to adhere to natural biopolymers ( e.g. , cellulose fibres ) can be beneficial to these organisms , such as by providing access to nutrient - rich sources .
in addition , the adhesion of bacteria to synthetic biomaterials ( e.g. , medical devices ) , such as those biomaterials that have been exposed to body fluids and contain adhered serum proteins , results in severe clinical consequences ( 4 ) .
adhesin - mediated adhesion to host surfaces also enables biofilm formation ( 5 ) , a multicellular lifestyle of bacteria that is associated with bacterial tolerance to antimicrobial agents , host defences , and other environmental challenges . due to their fundamental role in the host - pathogen interaction ,
bacteria have evolved a large variety of adherence - mediating components and strategies to enable their adhesion to the host .
pili are polymeric hair - like surface structures that contain an adhesin at its distal tip .
they are the most researched class of bacterial adhesins , particularly in gram - negative bacteria .
gram - positive organisms were also subsequently found to elaborate pili , and their function in adhesion and pathogenesis is being deciphered ( 6 ) .
these adhesins are capable of interacting with host molecules , including transmembrane proteins and ecm components ( 7 ) .
it is well - established that during infection , m. tuberculosis interacts with and enters host cells , including macrophages , epithelial cells , and dendritic cells .
this process is crucial to the organism s survival , replication , and dissemination ( 8) .
however , the adhesins mediating these fundamental processes has been largely unexplored and underappreciated ( 9 ) .
although several m. tuberculosis proteins have been documented to function in the attachment to host components ( table 1 ) , computational tools have predicted an abundance of additional uncharacterized m. tuberculosis adhesins ( table 2 ) .
a list of the currently known mycobacterium tuberculosis adhesins a list of the putative mycobacterium tuberculosis adhesins identified by computational analyses putative adhesins identified from kumar et al ( 18 ) and the mycobacrv web server ( http://mycobacteriarv.igib.res.in ) a major challenge to the treatment of tb patients is the escalating rates of drug - resistant m. tuberculosis strains .
a novel strategy for tb treatment and prevention involves targeting bacterial determinants of infection , rather than those of survival .
this would incapacitate the pathogen and ensure a natural clearance of the bacilli , without imposing selective pressure and amplifying the number of drug - resistant forms of the bacterium .
in addition , it would prevent the release of harmful products ( e.g. , endotoxins ) from lysed bacterial cells , which occurs with the use of bactericidal agents ( 2 ) .
however , due to a plethora of m. tuberculosis adhesion molecules , anti - adhesion tb therapeutics should target a combination of the major adhesins , possibly as an adjunct to the conventional tb therapeutics , to be effective .
for adhesion inhibition to be a viable intervention for tb treatment and prevention , further clarity on the entire repertoire of m. tuberculosis adhesins is needed .
the purpose of this work is to review the major methods available for the identification of m. tuberculosis adhesins .
these methods include adherence assays that utilize wild - type and gene knockout mutant strains , epitope masking and competitive inhibition analyses , ecm protein binding assays , microsphere adhesion assays , m. tuberculosis auto - aggregation assays , and in silico analyses .
comparing the adhesion capacity of wild - type and gene knockout mutant strains is a widely used approach to identify genetic determinants of adhesion and infection . in this assay ,
wild - type and gene knockout mutant strains infect host cells ( macrophages or epithelial cells ) in microtitre plates . a multiplicity of infection of between 1:1 and 10:1 ( bacilli to host cells ) and an infection time of 1 - 4 hrs ( usually 1 hr ) is generally used .
this is followed by washing to remove non - adherent bacilli and a lysis step ( usually with 0.1% triton x-100 ) to disrupt the host cells .
thereafter , serial dilutions of the cell lysates are plated onto agar plates to enumerate viable adherent bacterial cells , including those that have invaded the host cells . since intracellular bacilli
would have had to adhere prior to invading the host cells , the invaded bacteria also represent the total adhered population .
however , one may distinguish between the adherent versus invaded fraction using the aminoglycoside protection assay ( 10 ) to quantify the invaded bacilli .
this colony - forming unit ( cfu)-based adherence assay is advantageous in that it enables the cell association efficiency to be calculated from the total number of bacilli in the infection inocula .
in addition , it is a simple and relatively low - cost method that requires no specialized equipment .
this assay has been successfully used to identify the adhesin function of the pro - glu ( pe ) polymorphic gc - rich repetitive sequence ( pgrs ) protein encoded by rv1818c ( 11 ) , the heparin - binding hemagglutinin adhesin ( hbha ) ( 12 ) , and curli pili ( mtp ) ( 13 , 14 ) . in these studies ,
the deletion of the encoding genes ( rv1818c , rv0475 , and rv3312a ) resulted in a significant reduction in m. tuberculosis adhesion to macrophages and/or epithelial cells .
this assay has also been used to measure the binding of m. tuberculosis to ecm proteins .
be et al ( 15 ) incubated wild - type and pknd mutant m. tuberculosis strains with laminin for 1.5 hr .
the matrices were then lysed and plated onto agar plates for cfu assessment . a two - fold reduction in the adhesion to laminin
was observed for the mutant , indicating that protein kinase d is a laminin - binding adhesin .
the deletion of essential ( and even some non - essential ) m. tuberculosis genes pose a technical challenge to the generation of gene knockout mutants .
this prevents the utility of the previously described adherence assay to assess the possible adhesin function of the products that these genes encode .
this strategy makes use of purified / recombinant proteins or antibodies against the purified / recombinant protein to block the binding of m. tuberculosis to the host components .
hickey et al ( 16 ) used m. tuberculosis that was either untreated or treated with anti - cpn60.2 anti - bodies to infect macrophages .
unattached bacteria were removed by washing and attached bacilli were identified by cfu counting and microscopy .
the authors found that the m. tuberculosis strains with masked cpn60.2 displayed a significant decrease in the adhesion to macrophages compared with the unmasked m. tuberculosis .
the authors also used macrophages that were either untreated or treated with recombinant cpn60.2 protein , prior to the addition of m. tuberculosis .
the results indicated that m. tuberculosis displayed a decreased adhesion to cpn60.2-treated macrophages compared with untreated macrophages .
a similar masking strategy was used by abou - zeid et al ( 17 ) to identify the bcg85 complex of mycobacterium bovis bcg , which is also present in m. tuberculosis as the antigen 85 complex , as a fibronectin - binding adhesin . in this report
, the authors showed that m. bovis bcg that was pre - incubated with anti - bcg85 antibodies demonstrated a diminished capacity to adhere to fibronectin compared with unmasked m. bovis bcg .
they also found that fibronectin that was pre - incubated with purified bcg85a and bcg85b proteins inhibited the adhesion of m. bovis bcg to fibronectin .
in addition to their ability to bind to host cells , m. tuberculosis also adheres to ecm proteins , particularly collagens , fibronectin , and laminin .
therefore , numerous studies have identified m. tuberculosis adhesins based on their ability to bind to ecm proteins .
kumar et al ( 18 ) used an image - based enzyme - linked immunosorbent assay ( elisa ) to demonstrate the binding of the recombinant rv0309 , rv2599 , and rv3717 proteins to immobilized ecm proteins ( fibronectin , laminin , and/or collagen ) .
detection of protein binding was achieved using horseradish peroxidase conjugated anti-6x histidine antibodies and ortho - phenylenediamine dihydro - chloride .
alteri et al ( 19 ) used flow cytometry to measure the binding of wild - type and mtp - deficient m. tuberculosis strains to ecm proteins , by the detection of anti - ecm antibody complexes , using alexa fluor conjugate .
the binding of mtp to laminin was confirmed using a sandwich elisa . in this experiment ,
the authors used varying concentrations of laminin to demonstrate that immobilized purified mtp protein bound to this ecm protein .
similarly , using flow cytometry and elisa , pethe et al ( 20 ) showed that the mycobacterium smegmatis laminin - binding protein ( which is also expressed by m. tuberculosis ) binds to laminin . using elisa and
reverse elisa , kinhikar et al ( 21 ) demonstrated that purified recombinant malate synthase bound to fibronectin and laminin .
this was confirmed by fractioning the recombinant protein using sodium dodecyl sulphate polyacrylamide gel electrophoresis , treating the western blots with these ecm proteins , and detecting ecm protein binding using anti - ecm and secondary antibodies . these researchers also showed that recombinant malate synthase adhered to epithelial cells .
this was done by detecting bound malate synthase using anti - malate synthase antibodies and flow cytometry .
using a similar immunoblotting strategy to kinhikar et al ( 21 ) , espitia et al ( 22 ) and xolalpa et al ( 23 ) found that the fractioned recombinant rv1759c pe - pgrs protein and glutamine synthetase a1 bound to fibronectin , respectively .
although microspheres have generally been used in m. tuberculosis phagocytosis assays , they also have application in the study of bacterial adhesion .
esparza et al ( 24 ) used 1 m green fluorescent polystyrene microbeads coated with purified psts-1 abc phosphate transporter protein to interact with macrophages adhering to glass coverslips .
non - adherent microbeads were removed by washing and adherent microbeads were identified by analyzing randomly selected cells by confocal microscopy .
similarly , diaz - silvestre et al ( 25 ) used this technique to confirm the role of the 19-kda antigen ( lpqh glycolipoprotein ) as an adhesin .
chitale et al ( 26 ) used 0.3 and 1.1 m latex beads coated with recombinant mycobacterium cell entry-1 ( mce1 ) protein to infect hela cells cultured on glass coverslips .
the use of 1 m fluorescent latex beads has also been described , where fluorescence emission gives an indication of bead association ( 26 ) .
apart from their function in bacteria - eukaryotic cell interactions , adhesins also mediate cell - to - cell contact between bacterial cells and are , thus , key contributors to bacterial aggregation and biofilm formation .
menozzi et al ( 27 ) reported that incorporating purified hbha to m. tuberculosis cultures resulted in an aggregation of the bacilli , in a dose - dependent manner .
ramsugit et al ( 28 ) showed that a mtp - deficient m. tuberculosis strain displayed a significant reduction in bacterial aggregation and pellicle formation in detergent - free sauton s media compared with the wild - type strain .
both hbha and mtp were subsequently shown to also function as adhesins in the host - pathogen interaction ( 12 - 14 ) .
the identification of adhesins that promote m. tuberculosis auto - aggregation could , therefore , enable the identification of potential adhesins that are associated with host interaction .
kumar et al ( 18 ) screened all of the m. tuberculosis h37rv proteins through several bioinformatics tools and identified 20 novel putative adhesins ( table 2 ) .
this was achieved using spaan adhesin predictor ( 29 ) at a threshold of pad > 0.65 , subcellular localization prediction algorithms [ loctree ( 30 ) , psortb ( 31 ) , and subloc ( 32 ) ] , and removing potential human homologues that were identified by blast .
in addition , further filtering criteria for globular and low - molecular - weight proteins that were not previously reported in the literature were applied .
three of the prospective adhesins identified in that study ( rv0309 , rv2599 , and rv3717 ) were subsequently experimentally confirmed to bind to ecm proteins ( 18 ) .
the mycobacrv database of mycobacterial vaccine candidates provides information regarding possible adhesins of 22 human pathogenic mycobacterial species and their potential as vaccine candidates ( 33 ) .
this database uses spaan ( 29 ) at pad>0.6 and psortb ( 34 ) at a very stringent cut - off to identify adhesin and adhesin - like proteins . using the mycobacrv web server ( http://mycobacteriarv.igib.res.in )
, 37 novel prospec - tive adhesins were identified in m. tuberculosis h37rv ( table 2 ) .
comparing the adhesion capacity of wild - type and gene knockout mutant strains is a widely used approach to identify genetic determinants of adhesion and infection . in this assay ,
wild - type and gene knockout mutant strains infect host cells ( macrophages or epithelial cells ) in microtitre plates . a multiplicity of infection of between 1:1 and 10:1 ( bacilli to host cells ) and an infection time of 1 - 4 hrs ( usually 1 hr ) is generally used .
this is followed by washing to remove non - adherent bacilli and a lysis step ( usually with 0.1% triton x-100 ) to disrupt the host cells .
thereafter , serial dilutions of the cell lysates are plated onto agar plates to enumerate viable adherent bacterial cells , including those that have invaded the host cells . since intracellular bacilli
would have had to adhere prior to invading the host cells , the invaded bacteria also represent the total adhered population . however , one may distinguish between the adherent versus invaded fraction using the aminoglycoside protection assay ( 10 ) to quantify the invaded bacilli . this colony - forming unit ( cfu)-based adherence assay is advantageous in that it enables the cell association efficiency to be calculated from the total number of bacilli in the infection inocula .
in addition , it is a simple and relatively low - cost method that requires no specialized equipment .
this assay has been successfully used to identify the adhesin function of the pro - glu ( pe ) polymorphic gc - rich repetitive sequence ( pgrs ) protein encoded by rv1818c ( 11 ) , the heparin - binding hemagglutinin adhesin ( hbha ) ( 12 ) , and curli pili ( mtp ) ( 13 , 14 ) . in these studies ,
the deletion of the encoding genes ( rv1818c , rv0475 , and rv3312a ) resulted in a significant reduction in m. tuberculosis adhesion to macrophages and/or epithelial cells .
this assay has also been used to measure the binding of m. tuberculosis to ecm proteins . be et al ( 15 ) incubated wild - type and pknd mutant m. tuberculosis strains with laminin for 1.5 hr .
the matrices were then lysed and plated onto agar plates for cfu assessment . a two - fold reduction in the adhesion to laminin
was observed for the mutant , indicating that protein kinase d is a laminin - binding adhesin .
the deletion of essential ( and even some non - essential ) m. tuberculosis genes pose a technical challenge to the generation of gene knockout mutants .
this prevents the utility of the previously described adherence assay to assess the possible adhesin function of the products that these genes encode .
this strategy makes use of purified / recombinant proteins or antibodies against the purified / recombinant protein to block the binding of m. tuberculosis to the host components .
hickey et al ( 16 ) used m. tuberculosis that was either untreated or treated with anti - cpn60.2 anti - bodies to infect macrophages .
unattached bacteria were removed by washing and attached bacilli were identified by cfu counting and microscopy .
the authors found that the m. tuberculosis strains with masked cpn60.2 displayed a significant decrease in the adhesion to macrophages compared with the unmasked m. tuberculosis .
the authors also used macrophages that were either untreated or treated with recombinant cpn60.2 protein , prior to the addition of m. tuberculosis .
the results indicated that m. tuberculosis displayed a decreased adhesion to cpn60.2-treated macrophages compared with untreated macrophages .
a similar masking strategy was used by abou - zeid et al ( 17 ) to identify the bcg85 complex of mycobacterium bovis bcg , which is also present in m. tuberculosis as the antigen 85 complex , as a fibronectin - binding adhesin . in this report
, the authors showed that m. bovis bcg that was pre - incubated with anti - bcg85 antibodies demonstrated a diminished capacity to adhere to fibronectin compared with unmasked m. bovis bcg .
they also found that fibronectin that was pre - incubated with purified bcg85a and bcg85b proteins inhibited the adhesion of m. bovis bcg to fibronectin .
in addition to their ability to bind to host cells , m. tuberculosis also adheres to ecm proteins , particularly collagens , fibronectin , and laminin . therefore ,
numerous studies have identified m. tuberculosis adhesins based on their ability to bind to ecm proteins .
kumar et al ( 18 ) used an image - based enzyme - linked immunosorbent assay ( elisa ) to demonstrate the binding of the recombinant rv0309 , rv2599 , and rv3717 proteins to immobilized ecm proteins ( fibronectin , laminin , and/or collagen ) .
detection of protein binding was achieved using horseradish peroxidase conjugated anti-6x histidine antibodies and ortho - phenylenediamine dihydro - chloride .
alteri et al ( 19 ) used flow cytometry to measure the binding of wild - type and mtp - deficient m. tuberculosis strains to ecm proteins , by the detection of anti - ecm antibody complexes , using alexa fluor conjugate .
the binding of mtp to laminin was confirmed using a sandwich elisa . in this experiment ,
the authors used varying concentrations of laminin to demonstrate that immobilized purified mtp protein bound to this ecm protein .
similarly , using flow cytometry and elisa , pethe et al ( 20 ) showed that the mycobacterium smegmatis laminin - binding protein ( which is also expressed by m. tuberculosis ) binds to laminin . using elisa and reverse elisa , kinhikar et al ( 21 ) demonstrated that purified recombinant malate synthase bound to fibronectin and laminin .
this was confirmed by fractioning the recombinant protein using sodium dodecyl sulphate polyacrylamide gel electrophoresis , treating the western blots with these ecm proteins , and detecting ecm protein binding using anti - ecm and secondary antibodies .
this was done by detecting bound malate synthase using anti - malate synthase antibodies and flow cytometry . using a similar immunoblotting strategy to kinhikar et al ( 21 ) , espitia
et al ( 22 ) and xolalpa et al ( 23 ) found that the fractioned recombinant rv1759c pe - pgrs protein and glutamine synthetase a1 bound to fibronectin , respectively .
although microspheres have generally been used in m. tuberculosis phagocytosis assays , they also have application in the study of bacterial adhesion .
esparza et al ( 24 ) used 1 m green fluorescent polystyrene microbeads coated with purified psts-1 abc phosphate transporter protein to interact with macrophages adhering to glass coverslips .
non - adherent microbeads were removed by washing and adherent microbeads were identified by analyzing randomly selected cells by confocal microscopy .
similarly , diaz - silvestre et al ( 25 ) used this technique to confirm the role of the 19-kda antigen ( lpqh glycolipoprotein ) as an adhesin .
chitale et al ( 26 ) used 0.3 and 1.1 m latex beads coated with recombinant mycobacterium cell entry-1 ( mce1 ) protein to infect hela cells cultured on glass coverslips .
the use of 1 m fluorescent latex beads has also been described , where fluorescence emission gives an indication of bead association ( 26 ) .
apart from their function in bacteria - eukaryotic cell interactions , adhesins also mediate cell - to - cell contact between bacterial cells and are , thus , key contributors to bacterial aggregation and biofilm formation .
menozzi et al ( 27 ) reported that incorporating purified hbha to m. tuberculosis cultures resulted in an aggregation of the bacilli , in a dose - dependent manner .
ramsugit et al ( 28 ) showed that a mtp - deficient m. tuberculosis strain displayed a significant reduction in bacterial aggregation and pellicle formation in detergent - free sauton s media compared with the wild - type strain . both hbha and mtp
were subsequently shown to also function as adhesins in the host - pathogen interaction ( 12 - 14 ) .
the identification of adhesins that promote m. tuberculosis auto - aggregation could , therefore , enable the identification of potential adhesins that are associated with host interaction .
kumar et al ( 18 ) screened all of the m. tuberculosis h37rv proteins through several bioinformatics tools and identified 20 novel putative adhesins ( table 2 ) .
this was achieved using spaan adhesin predictor ( 29 ) at a threshold of pad > 0.65 , subcellular localization prediction algorithms [ loctree ( 30 ) , psortb ( 31 ) , and subloc ( 32 ) ] , and removing potential human homologues that were identified by blast .
in addition , further filtering criteria for globular and low - molecular - weight proteins that were not previously reported in the literature were applied .
three of the prospective adhesins identified in that study ( rv0309 , rv2599 , and rv3717 ) were subsequently experimentally confirmed to bind to ecm proteins ( 18 ) .
the mycobacrv database of mycobacterial vaccine candidates provides information regarding possible adhesins of 22 human pathogenic mycobacterial species and their potential as vaccine candidates ( 33 ) .
this database uses spaan ( 29 ) at pad>0.6 and psortb ( 34 ) at a very stringent cut - off to identify adhesin and adhesin - like proteins . using the mycobacrv web server ( http://mycobacteriarv.igib.res.in )
, 37 novel prospec - tive adhesins were identified in m. tuberculosis h37rv ( table 2 ) .
tb remains a major challenge . despite global efforts to improve our understanding of m. tuberculosis pathogenesis
, insufficient knowledge has been gained on the m. tuberculosis adherence mechanisms , the first ( and arguably the most critical ) step in the pathogenesis of this bacterium .
several m. tuberculosis adhesins have been identified ; however , computational analyses have predicted a large number of additional adhesin - encoding genes in this pathogen s genome .
several of these genes encode proteins belonging to the pe - pgrs and pro - pro - glu ( ppe ) protein families .
it , therefore , seems likely that key information regarding this organism s adherence mechanisms could be obtained by the study of the adhesin capability of proteins belonging to these families . with several methods available for the study of m. tuberculosis adhesion , as highlighted in this review , identifying novel m. tuberculosis adhesins is possible and should be explored further .
advances in gene disruption technologies open up the possibility of screening mutant libraries to identify m. tuberculosis genes involved in the pathogen s adherence .
adapting the adhesion methodologies to enable high - throughput screening of libraries of potential anti - adhesion therapeutics is needed and may have value in the control of this ravaging disease . | anti - adhesion therapy represents a potentially promising avenue for the treatment and prevention of tuberculosis in a post - antibiotic era .
adhesins are surface - exposed microbial structures or molecules that enable pathogenic organisms to adhere to host surfaces , a fundamental step towards host infection .
although several mycobacterium tuberculosis adhesins have been identified , it is predicted that numerous additional adherence - mediating components contribute to the virulence and success of this pathogen .
significant further research to discern and characterize novel m. tuberculosis adhesins is , therefore , required to gain a holistic account of m. tuberculosis adhesion to the host .
this would enable the identification of potential drug and vaccine targets for attenuating m. tuberculosis adherence and infectivity .
several methods have been successfully applied to the study and identification of m. tuberculosis adhesins . in this manuscript , we review these methods , which include adherence assays that utilize wild - type and gene knockout mutant strains , epitope masking and competitive inhibition analyses , extracellular matrix protein binding assays , microsphere adhesion assays , m. tuberculosis auto - aggregation assays , and in silico analyses . |
ever since the successful recording of 10 hz brain oscillations over the intact scalp of human subjects by berger in 1929 , the study of brain oscillations in the electroencephalogram ( eeg ) has become an increasingly important focus of interest in studying brain - behavior relationships .
brain oscillations are the result of the continue waxing and waning of electric field potentials generated simultaneously in a large number of vertically oriented apical dendrites of pyramidal nerve cells in the cerebral cortex ( niedermeyer and lopes da silva 1999 ) . in spite of having a cortical
read - out brain oscillations come about by direct or indirect interactions with other local and distal structures subsequently forming complex networks .
evolutionary views on human brain development and complexity suggest that the brain is comprised of several phylogenetically distinct networks ( maclean 1990 ) .
furthermore , it has been proposed that more complex networks operate using higher frequency ranges . in line ,
slow wave activity corresponding to delta ( 13 hz ) and theta ( 47 hz ) frequency range stems from the evolutionary older subcortical structures ( including the brainstem and septo - hippocampal complex ) . in agreement with this view
, electric stimulation of the brain - stem ascending reticular activating system ( aras ) elicits 14 hz ( delta ) cortical responses ( guyton 1976 ; but see knyazev 2011 ) , while electric stimulation of limbic areas evoke distinct 7 hz ( theta ) activity ( gray 1982 ) .
fast wave activity in the alpha ( 812 hz ) and beta ( 1330 hz ) frequency range , on the other hand , is suggested to find its origin in thalamo - cortical and cortico - cortical circuits respectively ( knyazev and slobodskaya 2003 ; knyazev et al .
2004 ; robinson 1982 , 1999 , 2000 , 2001 ) . in line with this view , michel et al .
( 1992 ) used 3-dimensional dipole modeling to show that the source of delta oscillations was deepest and most anterior , theta oscillations more posterior and less deep , alpha oscillations most posterior and highest on the vertical dimension .
thus , dominant rhythms shift from low frequency to higher frequency with increasing complexity of the brain , yet lower frequencies are suggested to be preserved and arguably reflect neural systems that are evolutionary more ancient .
although mostly speculative of nature , this conceptual framework may be helpful in the interpretation of findings on cross - frequency coupling and to guide further research .
the functional relevance of brain oscillations and their accompanying frequency underwent a thorough change in course of time from admitting that they are useful only for making inferences about global states of sleep and wakefulness ( e.g. , duffy 1962 ; thayer 1989 ) to acknowledging that oscillations may play a special role in large scale synchronization of brain functions ( buzsaki and draguhn 2004 ; salinas and sejnowski 2001 ; singer 1999 ) .
considerable evidence links different frequency brain oscillations with a range of cognitive processes , emotional states , and behaviors ( basar 1999 ; cantero and atienza 2005 ; klimesch 1999 ; knyazev 2007 ; nunez 2000 ; varela et al .
importantly , studying these brain - behavior relationships is usually limited to examining oscillations in a pre - specified band , whereas brain functions are believed to be realized by simultaneous oscillations in various frequency bands ( basar 2006 ) .
additionally , studying interactions and relations between the different frequency bandwidths provides a logical next step in unraveling the workings of the human brain and its functions .
indeed , more recent studies report on statistical relations among activities in different frequency bands .
firstly , a range of methods have been suggested to measure phase coordination between different frequencies . to explore phase coupling between different frequencies ,
the calculation of bicoherence is an extension of second order statistics used in determining signal properties in the time and frequency domains , in the form of fourier transform ( schack et al .
this measure mixes phase and amplitude relations between signals or the phase - amplitude relationship between different frequencies . in order to study a pure phase
phase relationship , that is phase synchronizations , across frequencies , a method to estimate time varying quadratic phase coupling of electrophysiological signals , the bi - phase locking value was introduced ( darvas et al .
n : m phase synchronization , and involves the synchrony between phase values at one frequency band and phase values at an integer multiple of another frequency band ( tass et al .
this method is useful for examining amplitude - independent phase - locking , but is limited to coupling among integer - multiple frequency bands ( e.g. , 10 , 20 , 40 hz )
. in general , cross - frequency phase coordination in the human brain suggests nonlinear interactions , and it is speculated that such interactions play a crucial role in the coordination of complex cortical computations ( darvas et al .
another type of cross - frequency coupling is called phase - amplitude coupling and refers to the synchronization of oscillation power fluctuations with the phase of a slower oscillation ( jensen and colgin 2007 ) .
for example , in the entorhinal and prefrontal cortices , the amplitude of gamma oscillations increases during specific phases of theta ( chrobak and buzsaki 1998 ; canolty et al .
2007 ) , amplitude modulation of occipital high - frequency oscillations in the gamma range may be phase locked to a slow - frequency oscillation in the delta frequency range ( handel and haarmeier 2009 ) . both phase - phase and phase - amplitude cross - frequency coupling have been shown to relate to specific cortical areas and specific stages of information processing and have received much attention in recent works .
although another type of cross - frequency relationship called amplitude - amplitude coupling has received less attention , this review will provide evidence that the amplitude - amplitude coupling may reflect some global properties of the brain oscillatory systems , which might be relevant to the description of stable individual differences , or emotional and motivational states .
amplitude - amplitude associations between different frequency eeg bands could be studied both in the within- ( i.e. , across a number of states within each individual ) and between- ( i.e. , across a sample of subjects ) subject domain .
given the large number of eeg variables ( i.e. , a multitude of cortical sites and frequency bands ) , these associations have been frequently analyzed by means of multivariate techniques , such as factor analysis , or principal component analysis .
these techniques are used as a means for reducing the amount of correlated data , with no a priori predictions as to the relationship between different frequency bands . as a result
( 1987 ) revealed three factors that accounted for most of the variability in the data : ( 1 ) low versus high frequency , ( 2 ) beta frequency , and ( 3 ) frontal versus posterior factor .
in his pioneering work robinson ( 1982 , 1999 , 2000 , 2001 ) used factor analysis to test predictions of his arousability theory .
the theory posits that the thalamo - cortical system exerts a generally inhibitory effect on the brainstem system and , hence , amplitudes of alpha and delta waves should be inversely related to each other ( robinson 1999 ) .
the strength of this negative relationship reflects general cortical arousability and is associated with personality characteristics ( robinson 2001 ) . although some assumptions of this theory are speculative and do not seem to be supported by more recent findings , robinson has been able to confirm its main predictions empirically .
he performed factor analysis of filtered in alpha , theta , and delta bands auditory evoked potentials registered in a relatively large sample of aged subjects .
considering the unrotated factor solution , robinson showed that overwhelming part of the variance could be explained by the first component showing high positive loadings from all three bands .
the second component provided an opportunity to observe negative relations between variables . here , as predicted , negative covariance between delta and alpha bands emerged .
the behavioral relevance of this inverse relationship between alpha and delta waves to personality was confirmed by the discovery of its lower magnitude in individuals with high scores on extraversion and neuroticism ( robinson 2001 ) .
( 2003 , 2004 ) repeated this analysis for recorded in resting condition spontaneous eeg and obtained similar results .
it appeared that , as compared to adults , children had significantly lower scores on the factor measuring negative relationship between alpha and delta powers .
these factor scores were positively related to psychometric measures of neuroticism , behavioral inhibition , and emotional symptoms and were inversely related to measures of extraversion , behavioral activation , and conduct problems .
this measure showed trait - like properties being uniformly higher in high trait anxiety subjects independently of experimental manipulations ( knyazev et al .
a within - subject measure of delta - alpha anticorrelation was explored by knyazev and slobodskaya ( 2003 ) and knyazev et al .
this measure was positively related to relative alpha power , inversely to relative delta and theta power .
in addition , the within - subject measure showed a moderate positive relation to the respective between - subject measure and with psychometric measures of behavioral inhibition .
such a pattern of correlations implies that the within- and the between - subject estimates measure a comparable construct that may underlie a mechanism involving the increase of alpha oscillations and the inhibition of delta and theta oscillations ( knyazev et al .
noteworthy , most of these associations were not significant in children and could be ascribed to immaturity of this hypothetical mechanism .
apart from these factor - analytic studies , a large body of evidence coming from different experimental manipulations and observations in psychopathological and juvenile populations confirms a general tendency for alpha and slower ( delta and theta ) frequencies to be inversely related to each other , with a prevalence of slow frequencies in some pathological conditions and early developmental stages being associated with impulsivity and disinhibition ( for a review see knyazev 2007 ) .
for example , delta oscillations have been associated with the approach - related behavior and reward sensitivity ( knyazev et al .
interestingly , the steroid hormone testosterone has been associated with approach - related motivational tendencies , reward sensitivity and aggression ( van honk et al .
testosterone is the end - product of the hypothalamic - pituitary - gonadal ( hpg- ) axis and its target regions include widely distributed steroid networks in the limbic system ( wood 1996 ) that modulate core motivational and emotional drives . in a previous placebo - controlled study van honk et al .
( 2004 ) showed that a single administration of testosterone reduced punishment sensitivity and increased reward dependency as subjects made more disadvantageous , risky decisions in the iowa gambling task . in an additional resting state
eeg study significant increases in frontal delta oscillations were observed after a single administration of testosterone ( schutter and van honk 2004 ) .
all these data fit the proposal that delta oscillations might be somehow related to the activity of motivational brain circuits ( knyazev 2007 ) .
in addition to the significant increase in delta oscillations after testosterone administration , schutter and van honk ( 2004 ) also found a reduction of coupling between frontal delta and beta oscillations .
this finding initiated a series of studies investigating the delta - beta coupling in different groups of subjects and in different conditions .
an association study yielded comparable results as males who were high in baseline salivary testosterone exhibited significantly reduced frontal delta - beta coupling compared to those low in testosterone ( miskovic and schmidt 2009 ) .
more recently , a functional magnetic resonance imaging ( fmri ) study showed that exogenous elevations of testosterone levels comparable to the previous studies reduce functional cross - talk between the amygdala and orbitofrontal cortex during passive face viewing ( van wingen et al .
in contrast , the stress - related hormone cortisol is a steroid endocrine marker of behavioral inhibition and anxiety ( kalin et al .
schutter and van honk ( 2005 ) demonstrated that higher levels of cortisol were associated with increased frontal delta - beta coupling in healthy subjects .
furthermore , a single administration of cortisol in healthy volunteers was found to significantly increase the coupling between delta and beta oscillations ( van peer et al .
2008 ) , providing support for the modulatory effects of steroid hormones on cross - frequency coupling , as well as the proposed mutually inhibitory function between cortisol and testosterone ( viau 2002 ) .
this series of steroid hormone - eeg studies provide evidence that the magnitude of the correlation between powers of slow and fast waves can be manipulated by factors that are associated with the subject s physiological and subsequent mental state .
indeed , a statistical significant relationship , rho(51 ) = 0.33 : p = 0.02 , has been observed between reduced individual delta - beta coupling based on the cross - frequency correlation computed from a 4 min baseline recording and increased scores on the buss - perry physical aggression scale ( schutter 2011 ) . moreover , knyazev et al . ( 2005 ) showed that relative to baseline the delta - beta coupling increased when subjects were expecting bad news but did not change when they expected good news .
2010b ) showed that a high socially anxious group from normative population showed significantly greater delta - beta coupling than a low socially anxious group while anticipating public speaking .
a number of studies analyzed the delta - beta coupling in groups with anxiety - related pathological conditions .
( 2009 ) provides evidence that individuals diagnosed with social anxiety disorder ( generalized subtype ) exhibit high levels of eeg delta - beta coupling during the anticipation of a self - presentation task , whereas cognitive behavioural therapy significantly reduces the anticipatory delta - beta coupling .
moreover , higher frontal delta - beta coupling was registered in children of parents with social phobia as compared to children of healthy parents ( miskovic et al .
( 2011 ) showed that successful psychotherapy in social phobic patients was associated with decreases in delta - beta coupling paralleled by reductions in anxiety symptoms at rest and during speech anticipation . in this study twenty - five subjects diagnosed with social anxiety disorder underwent 12 weekly sessions of standardized group cognitive behavioral therapy . while increased delta - beta coupling was observed in the clinical group during the pretreatment phase as compared to control participants with low social anxiety , reductions in symptom severity as well as normalization of the delta - beta coupling were observed during the treatment and post - treatment phase of the study .
2010 ) , on the other hand , have found lower delta - beta coupling in patients with obsessive - compulsive disorder than in age- and sex - matched controls . according to the authors , obsessive - compulsive disorder
is related not only to higher activity levels in frontal cortical networks , but also to a fronto - subcortical functional disconnection . in table 1
a summary of the studies and their main findings can be found.table 1overview studiesstudypopulationcross - frequency couplingmain findingrobinson ( 2001)healthydelta - alphalower coupling in individuals scoring high on extraversion and neuroticismknyazev and slobodskaya ( 2003)healthydelta - alphahigher coupling associated with increased behavioral inhibitionknyazev et al .
( 2003)healthydelta - alphalower coupling associated with increased extraversion and behavioural activation ( bas)schutter and van honk ( 2004)healthydelta - betareduced coupling after testosterone administrationschutter and van honk ( 2005)healthydelta - betahigher basal cortisol levels associated with increased couplingknyazev et al .
( 2006)healthydelta - betaincreased coupling during state anxietyknyazev and slobodskoj - plusnin ( 2007)healthytheta - gammaincreased coupling under situation of reward in high bas subjectsvan peer et al .
( 2008)healthydelta - betaincreased coupling after cortisol administrationmiskovic and schmidt ( 2009)healthydelta - betahigher basal testosterone levels associated with reduced couplingmiskovic et al .
( 2009 , 2011)patientsdelta - betareduced coupling following successful behavioral therapy of social anxietymiskovic et al .
( 2010b)patientsdelta - betaincreased coupling during speech anticipation in patients with social anxiety disordervelikova et al .
( 2010)patientsdelta - betareduced coupling in patients with obsessive compulsive disorderknyazev ( 2011)healthydelta - betaincreased coupling during state anxietyputman ( 2011)healthydelta - betahigher coupling associated with attentional bias towards threatschutter ( 2011)healthydelta - betalower coupling associated with higher physical aggression scores in sum , evidence from several lines of fundamental and clinical neuroscientific research demonstrates that cross - frequency eeg relations are associated with various aspects of human behavior , providing a possible indirect electrophysiological correlate for cortico - subcortical interactions ( knyazev 2007 ; robinson 1982 ; schutter et al .
empirical studies have demonstrated that delta - alpha and delta - beta frequency coupling in the human eeg are associated with phenomenology , behavior , and hormones . despite the available evidence ,
the cross - frequency coupling approach in its present form has several conceptual and methodological issues that will be discussed in more detail below .
the frequency information buried within the eeg signal reveals an important physiological property by which the brain operates as rhythmic oscillations constitute an important organizing principle of neural functions .
extracting the different frequency components from the signal provides a means to establish an association between brain states and function .
traditionally , high frequency low amplitude ( e.g. , beta ) oscillations are associated with a highly active cerebral cortex ( e.g. , awake and alert ) , whereas slow frequency high amplitude ( e.g. , delta ) oscillations are linked to low aroused and relative inactive cortical state ( e.g. , deep sleep ) .
one line of evidence comes from the observation of alpha waves in the eeg signal over the occipital cortex when subjects have their eyes closed and no visual information is being processed by the visual system ( berger 1929 ) .
there is evidence to suggest that the alpha oscillations find its origins in thalamo - cortical loops .
beta oscillations and even higher frequencies are proposed to have a cortico - cortical basis indexing local information processing and have been associated with active inhibition processes that are possibly mediated by gaba - ergic interneurons ( jensen et al .
theta - oscillations have been associated with the subcortical septo - hippocampal region and the anterior cingulate cortex ( acc ) and are connected to memory , anxiety and punishment learning ( gray 1982 ) .
finally , delta oscillations have been linked to the locus coeruleus and the brain stem ascending reticular activating system ( leung and yim 1993 ; robinson 1999 ) . on the behavioral level delta waves
neuroimaging studies in humans have demonstrated an anatomical correspondence between the putative location of delta wave generation and the projections of the mesencephalic dopamine system to the cerebral cortex .
indeed , studies using dipole modeling place the site of cortical delta wave generation in anterior medial frontal cortex ( michel et al .
studies correlating positron emission tomography ( pet ) and eeg also indicate a positive correlation between waking delta and pet metabolism in the medial frontal cortex ( alper et al .
( 2009 ) have shown that delta activity in the rostral anterior cingulate cortex inversely correlates with the nucleus accumbens responses to reward and is associated with higher anhedonia scores .
importantly , all these data show that delta activity increases in states associated with a need for some reinforcement and decreases when this reinforcement is obtained .
it should furthermore be noted that these frequencies are all present in the awake eeg of human subjects .
moreover , delta and theta oscillations originate in the subcortical motivational circuits , while the generation of alpha and beta oscillations are suggested to be more closely related to cortical structures that are responsible for higher order mental functions including cognitive regulation .
however , the precise functional meaning of the different frequency bands remains to be determined .
it should be emphasized that although we review works studying the delta - alpha and the delta - beta interactions together under the concept of cross - frequency coupling , they probably reflect quite different phenomena .
moreover , the measures that were used in these two kinds of studies are also different .
part of the answer to the previous question may come from studies that will establish the neural generators of these oscillations and how the coupling between the different frequency bands comes about . in most of earlier studies ,
spectral power measures were averaged across electrode locations and inferences about the localization of the effect could not be made .
some studies , however , suggest that this effect might relate to the prefrontal cortex ( schutter et al . 2006 ; miskovic and schmidt 2009 ; van wingen et al . 2010 ) .
( 2010 ) used source localization technique to reveal possible subcortical localization of the observed effects . whereas beta oscillations were primarily found in the cerebral cortex
, delta oscillations appear to originate from the insular cortex , a structure that is directly connected to the subcortical structures including the brain stem .
however , without the proper methods to determine the neural sources responsible it is impossible to draw any definite conclusion concerning the origin of these brain rhythms .
more studies with a more meticulous analysis of precise localization of the cross - frequency coupling are needed . because , due to volume conduction , the eeg signal does not give precise localization of observed effects , more sophisticated analysis methods , such as independent component analysis and interleaving functional neuroimaging with eeg recordings , may prove useful in this effort .
the majority of studies show that the delta - beta coupling is increased during anxiogenic situations , after administration of potentially anxiogenic drugs , and in groups with presumably higher anxiety levels ( but see velikova et al .
the question arises whether this effect is limited to anxiety or can be observed in other motivationally relevant states as well . in other words ,
what is the specificity of the cross - frequency coupling ? to our knowledge , there are only two studies currently available that suggest that the cross - frequency coupling extends to other psychological states as well . in the first study evidence
was found that in reward sensitive subjects the theta - gamma ( 3040 hz ) coupling increases in situations that presumably elicit positive emotional arousal ( knyazev and slobodskoj - plusnin 2007 ) .
the second study refers to the finding that physical aggression is linked to reductions in delta - beta coupling ( schutter 2011 ) .
a possible reason that relations with alpha oscillations are not always observed may be due to the fact that the cross - frequency relations are sometimes studied during relative active states and under these conditions alpha wave activity as a rule is desynchronized .
moreover , in resting state conditions where alpha waves are present in the signal , activity recorded from the anterior scalp sites from which the cross - frequency coupling is often recorded could be potentially confounded by activity that originates from the posterior sites due to volume conduction of the scalp . as a result interrelations involving alpha oscillations over the frontal regions could thus be masked by alpha oscillations which have a different origin .
it should also be noted that using extracranial eeg recordings the frequency range of activity that can be measured from the surface is limited and therefore not suitable to study brain signals in very fast frequencies ( e.g. , > 100 hz ) .
additionally , the cross - frequency coupling does not need to behave in a linear fashion per se .
there is ample evidence from eeg research showing the importance of studying non - linear relations between electric brain signals in understanding function and behaviour ( darvas et al .
2009 ) showed that interactions between distal brain regions can be understood in terms of quadratic relationships between different frequency bandwidths .
the reported cross - frequency couplings are based on correlational computations and consequently do not provide information on the direction of information flow .
it remains therefore unclear whether slow or fast waves drive the coupling and under what circumstances .
there is some evidence that delta waves are capable of influencing the delta - beta coupling .
for example , the observed increases in delta oscillations paralleled by a reduction in the coupling between delta and beta oscillations after a single administration of testosterone suggest a modulation of the cross - frequency coupling driven by a change in delta wave activity ( schutter and van honk 2004 ) . in another study evidence
was provided that the delta - beta coupling may be more sensitive to variations in delta activity than to beta activity ( schutter et al .
( 2005 ) found that delta activity measured before induction of an anxious state predicted beta activity after the induction , but not vice versa .
importantly , neither the strength nor the sign of the coupling provides information whether the interaction reflects a bottom - up or top - down process that is either inhibitory or excitatory .
it has been proposed that anti - correlations may reflect a top - down inhibitory process , but due to the limitations of the linear approach the anti - correlation may also reflect a bottom - up excitatory process .
incorporating additional phase information or introducing phase lags in computing the correlations as an index of the cross - frequency coupling may be helpful in unraveling directional information of the coupling . except for
one published study by knyazev and slobodskaya ( 2003 ) all studies reporting on the cross - frequency coupling in the existing literature are based on a sample based ( between - subjects ) approach and extrapolated to the individual ( within - subject ) domain ( cf .
this extrapolation raises the issue of construct validity as to whether or not the sample - based approach ( between - subjects ) can be used to index the individual ( within - subject ) level .
( 2004 ) found good agreement between the individual ( within - subject ) and sample - based ( between - subjects ) measures of delta - alpha anti - correlation .
moreover , in line with the sample - based approach an association between lower individual ( within - subject ) delta - beta coupling and increases in physical aggression has recently been observed ( schutter 2011 ) . in spite of these promising findings ,
future studies are needed to establish the relation between individual ( within - subject ) cross - frequency coupling and behaviour , as well as research that examine the correspondence between the sample - based ( between - subjects ) and individual - based ( within - subject ) approach in more detail .
finally , the frequency correspondence between the discussed amplitude - amplitude coupling and the well documented phase - amplitude coupling may be more than just a coincidence .
furthermore , phase - phase cross frequency relations may also provide another way of studying the electrophysiological properties underlying brain function and behaviour ( darvas et al . 2009 ) .
the simultaneous investigation of these different approaches in the same subjects under comparable conditions may bring forth exciting new insights into the operational dynamics of the human brain . a recent study by knyazev ( 2011 ) attempted to clarify some of these questions . in this study ,
independent component analysis and source localization techniques were used to identify temporally correlated spatial patterns that most reliably show the phenomenon of between - subject delta - beta correlation .
results of this analysis show that in an anxiogenic situation , the delta - beta correlation increases in a network of cortical areas which includes the orbitofrontal and the acc as its main nodes .
the increase of the correlation is accompanied by an increase of delta power and connectivity in the same cortical regions .
analysis of the within - subject delta - beta amplitude - to - amplitude and phase - to - amplitude coupling showed that in an anxiogenic situation , in subjects with higher scores on state anxiety the couplings also tend to increase in the same set of cortical areas .
this pattern of results suggests that the increase of delta power in medial frontal and orbitofrontal cortices during an anxiogenic situation in high state anxiety subjects , might be the driving force behind the ( between - subject ) cross - frequency coupling and that this coupling is closely related to the within - subject cross - frequency amplitude - amplitude and phase - amplitude coupling .
the introduction of the eeg by berger in 1929 hallmarked an important step forward in studying brain - behavior relationships .
research has shown that brain functions are realized by simultaneous oscillations in various frequency bands ( basar 2006 ) .
in addition to examining oscillations in pre - specified bands , interactions and relations between the different frequency bandwidths is another important aspect that needs to be considered in unraveling the workings of the human brain and its functions .
the aim of the present overview was to show that the concept of cross - frequency relations may be a useful and valuable approach to study the neural processes associated with motivation and emotion .
the first series of studies have provided evidence that the cross - frequency coupling between slow and fast wave oscillations is sensitive to steroid hormones and associated with varying motivational states in which normal and pathological forms of anxiety have received most attention .
recent data showing that changes in the cross - frequency coupling can be observed following successful psychotherapy is notable ( miskovic et al .
further research designed to extend these findings to other ( pathological ) conditions and to explore the specificity and sensitivity of the cross - frequency coupling in the healthy and clinical population is necessary . in spite of the remaining issues surrounding the cross - frequency approach , studying interrelations between different brain wave oscillations | research has shown that brain functions are realized by simultaneous oscillations in various frequency bands .
in addition to examining oscillations in pre - specified bands , interactions and relations between the different frequency bandwidths is another important aspect that needs to be considered in unraveling the workings of the human brain and its functions . in this review
we provide evidence that studying interdependencies between brain oscillations may be a valuable approach to study the electrophysiological processes associated with motivation and emotional states .
studies will be presented showing that amplitude - amplitude coupling between delta - alpha and delta - beta oscillations varies as a function of state anxiety and approach - avoidance - related motivation , and that changes in the association between delta - beta oscillations can be observed following successful psychotherapy .
together these studies suggest that cross - frequency coupling of brain oscillations may contribute to expanding our understanding of the neural processes underlying motivation and emotion . |
diagnosis of neoplastic disease often arouses fear and negative associations in patients because of the serious prognosis .
the chance of survival of patients with malignant neoplasms has improved significantly because of progress in medical research in recent years .
cancer is already not associated with death only ; people more and more often think about it as a chronic disease .
worldwide about 11 million cases are diagnosed each year with the mortality rate about 7 million .
the incidence of neoplastic diseases increases with age as in the case of chronic neurological diseases and diseases of the cardiovascular system [ 2 , 3 ] .
the american cancer society estimates the number of new diseases and deaths from neoplasms in the united states every year
. 1 596 670 new cases and 571 590 deaths were estimated in 2011 , while in poland 131 063 new cases and 93 060 deaths were observed in 2008 .
reducing the mortality rate and frequency of disease recurrences and improving body functionality are traditional goals of treatment .
neoplastic disease affects all spheres of human activity so the necessity of assessment of the quality of life is emphasized in the case of patients treated oncologically .
obtained results of the histopathological examination and molecular marker test enable one to choose the appropriate method .
surgery is another technique which consists in removing the tumour together with a healthy tissue margin or whole organ with growing cancer .
chemotherapy is the next kind of treatment and consists in administering medicines in large doses at given time intervals .
palliative treatment is used in the advanced stage of disease ( the term comes from the latin : pallium cloak , palliare to cloak ) .
it is an approach aimed at relieving or modifying signs and symptoms of progressive chronic disease resistant to curative treatment with unfavourable prognosis .
oncological treatment produces many adverse symptoms but it should be remembered that most patients cope with disease in an adaptive way [ 1 , 6 ] .
earlier diagnosis of cancer and increasing effectiveness of treatment methods is a condition for improving outcomes .
cooperation of physicians who conduct surgical , systemic ( chemical and hormonal ) treatment and radiotherapy is becoming very important .
treatment that is the best from a medical point of view and most reasonable economically is more and more often selected .
however , it is necessary to avoid the situation where efforts towards economical rationalization could cause reduction in the range of health services .
the quality of life in the case of neoplastic disease depends on the type of cancer , its stage and location , possibilities of treatment and prognosis .
malignant cancer makes the quality of life worse , most often in the advanced stage when people with this disease feel pain and suffering .
diagnosis alone arouses dread and feelings of helplessness which significantly diminish the level of quality of life .
patients feel fear of death , worry about the fate of their relatives , feel dejection , have a sense of injustice , and even fall into depression . calming and support
the attitude towards cancer is starting to change with the development of new treatment methods .
this action was directed towards society in order to improve knowledge about the disease , its symptoms and prophylaxis . despite numerous campaigns many people still downplay symptoms of the disease , and
but attitudes are changing and more and more people treat disease as one element in the treatment process . in 1951 shands and his collaborators described psychological mechanisms in patients with cancer .
they observed that communication with the patient becomes more difficult with progression of the disease .
according to modlinska and her colleagues the fearful reaction to neoplastic disease projects onto quality of life significantly in patients above 65 years old at the terminal phase of disease while in older patients problems with physical activity are prevalent .
working with people at the terminal phase of neoplastic disease needs extraordinary dedication to others and also patience and understanding . today the demand of professional assistance at the time when the disease becomes incurable puts new challenges before the health care systems around the whole world .
this challenge is qualitative in its nature ( because of raising expectations and treatment possibilities ) and also quantitative because of the aging of societies and increasing morbidity of diseases of respiratory and cardiovascular systems as well as neoplasms . in the case of incurable neoplastic disease a several - week ,
sometimes several - month period when the patient is close to death is observed . at
the advanced stage of chronic disease begins at the moment when the patient is qualified for palliative care . due to the clinical state and
the pre - terminal phase is the first one , in which the patient 's general state is quite good . at this time the care relies on periodic medical and nursing consultations in a palliative medicine clinic .
the terminal phase is the next one , when the patient 's general state begins irreversible deterioration that increases at a visible pace . in most cases
the dying phase ( agony ) is the last one , which immediately precedes the death of a patient .
it takes several days , sometimes a few hours . at this time multi - organ failure
it is said that people in the advanced incurable phase of neoplastic disease are qualified for terminal care , hospice , or palliative care at the end of life .
studies of people dying from cancer conducted in the netherlands and italy prove that escalation of symptoms and disability occurs three months before death regardless of age or type of neoplasm .
according to the agency for healthcare research and quality the end of life may be defined in various ways : firstly , as active dying when we can expect death within several hours or days ; secondly , as a readiness ; and thirdly , as disease progression that is specified by objective examinations results .
special interest in the problem of quality of life in medicine appeared in the 1970s .
the medical and non - medical outcomes of health care in the domain of oncology , psychiatry , rheumatology , internal medicine and gerontology began to be assessed .
therefore , a new concept of a model for medicine was created ( holistic model ) which was responsible not only for prolongation of the patient 's life but was also responsible for making the patient 's life active and similar to the period before disease [ 15 , 16 ] . according to
the who definition the quality of life means the way individuals perceive their living position in a cultural context and value system in which they live and in relation to their tasks , expectations and standards set by environmental determinants . who includes physical and mental conditions , degree of independence , social relationships , environment , religion , beliefs and views in the scope of the quality of life [ 16 , 17 ] .
in relation to neoplastic disease knippenberg notes that objective indicators of patient quality of life ( assessed by physicians ) are replaced by subjective assessments by patients .
it is not uncommon that there are significant differences in assessing the quality of life based on objective and subjective criteria .
siergist j. believes that research on the quality of life in the case of chronic diseases complements data obtained from diagnostic examinations and laboratory tests .
the author states that research on the quality of life fulfils different functions in medicine and may indicate needs of patients previously unrecognized by the physician related to the provision of medical care outside the hospital .
in addition , it shows the patient 's point of view , which may differ from professional medical knowledge .
subjective assessments of patients can be a source of additional information that could be useful for therapeutic decision making .
they arise from the fear of death and also from fear about the fate of relatives .
it often happens that the patient is not informed sufficiently about their character and effects .
on the one hand , hope about possible decrease of symptoms or complete remission of disease affects quality of life in patients with neoplasms . on the other hand ,
the communication between physician and patient is a very important factor affecting quality of life at the terminal phase of neoplastic disease .
many patients die with pain and other distressing symptoms that are not managed in the right way .
these patients often receive onerous , aggressive care that makes their quality of life worse .
skills of empathic listening to complaints of the patient and relatives , touch and also silence of persons from the medical staff or volunteers play an important role . until recently ,
estimates of overall survival and disease - free survival were the primary criteria for assessment of oncological treatment effectiveness .
currently , attention is drawn to additional elements , e.g. impact of the disease and the applied treatment on the functional and mental state of patient . to assess the quality of life several questionnaires are often used at the same time .
this follows from the fact that it is difficult to create one survey form that enables assessment of the patient as a
her / his somatic and mental state , social relationships , and physical well - being .
this is a questionnaire developed in order to assess quality of life in patients with neoplasms .
it was created by the quality of life group established at the european organisation for research and treatment of cancer ( eortc ) .
it consists of five parts and evaluates five levels of patient activity : physical , emotional , cognitive , social and living condition .
the first three parts define the severity of symptoms ( pain , fatigue , nausea and vomiting ) , overall assessment of health status and quality of life .
in addition , individual questions are formed to assess the intensity of other associated symptoms ( constipation , diarrhoea , shortness of breath , sleep disturbances ) .
apart from that , the assessment of disease influence on patient economic condition is performed by the patient .
separate modules are developed in order to assess quality of life for patients with specific cancers , e.g. a module for patients with lung carcinoma ( qlq - lc13 ) .
the qlq - c15-pal questionnaire is a shortened version of qlq - c30 that has been developed for assessment of quality of life for patients undergoing treatment in palliative care units .
this questionnaire is used for research on advanced incurable neoplasms with median survival about several months [ 7 , 18 , 19 ] . functional assessment of chronic illness therapy ( facit ) is a set of tools for measurement of quality of life related to health condition in patients with various chronic diseases .
the facit questionnaire is derived from a group of fact questionnaires ( functional assessment of cancer therapy ) .
it evaluates physical condition , social / family life , emotional state and everyday activity .
each question is rated on a scale from 0 to 5 , where 0 is the lowest and 5 the highest quality of life .
some of them exist in over 50 language versions , which allows international comparison of people from various environments .
separate modules are used for assessment of quality of life in patients with a specific neoplasm , e.g. fact - b ( functional assessment of cancer therapy breast ) .
the introduction of palliative care early in the disease together with curative treatment is essential . about 25% of patients
this is related to concern of caregivers that the patient does not fall into depression .
the recommendations contained in the council of europe recommendations on palliative care indicate the advisability of referring patients to palliative care institutions for patients with chronic , progressive , limiting life diseases as early as possible , even during curative treatment . the hospice is the place where palliative care is used most often .
the improvement of quality of life has a positive influence on the positive course of the disease . according to jocham and
associates , patients undergoing palliative care often complain of nausea and vomiting ( 591% ) , cancer pain ( 1184% ) , breathlessness ( 2164% ) , fear and depression ( 27% ) .
johnsen in similar research showed that the most common complaints of patients were related to fatigue ( 57% ) , limitations in performing social roles ( 51% ) , insomnia ( 48% ) and pain ( 39% ) .
nausea and vomiting can cause many complications , e.g. metabolic acidosis , aspiration pneumonia , hypokalaemia .
pain occurs in 7080% of patients in the terminal phase of disease and its causes are diverse .
pain that occurs in patients with advanced neoplastic disease is often of chronic and stable nature .
acute pain occurs periodically and is related to , for example , painful therapeutic and diagnostic procedures requiring a separate procedure .
as many as 80% of patients complain of having more than one kind of pain .
pain is divided into nociceptive , neuropathic and mixed type of pain according to their pathogenesis .
neuropathic pain arises following damage of nerve fibres included in the pain pathways . as a rule it is more difficult to treat , and
this type of pain is hard to relieve in 1015% of patients despite progress in pain treatment .
for this reason , patients experience discomfort and this can lead to avoidance of contacts with others .
it is caused , among others , by reduction in secretion of saliva , chemotherapy , radiotherapy or medication .
taste disturbance is another problem faced by patients during the last weeks of life . in this period patients
this leads to loss of body weight , which is associated with decreased immunity and depression .
administration of laxatives necessary in case of constipation ( the result of using opioids , radiotherapy , chemotherapy , or dietetic mistakes ) is a cause of diarrhoea .
lymphoedema is a complaint which is manifested by increased weight of the limb , causing restriction of movement and sensory disturbances .
according to the who , palliative care is a way of improving quality of life of patients and their families facing the problems associated with life - threatening disease by preventing and alleviating suffering , early identification of problems , the best assessment and treatment of pain as well as other physical , psycho - social and spiritual problems .
palliative care is aimed at meeting somatic , psycho - social and spiritual needs by early identification of needs and threats , preventing and alleviating suffering and supporting families during illness of a loved one .
end of life care is used in patients who are close to death ( last weeks / days of life ) . at this time
the second edition of the national consensus project clinical practice guidelines for quality palliative care was published in 2009 .
according to that publication palliative care is integrated medical care provided by a team of specialists in many fields such as physicians , nurses , clergy , social workers and other health care workers focused on aiding in relief of suffering and giving support to ensure the best quality of life of people with incurable illness and their families .
it should be conducted until the death of the patient and involve the patient 's family during the mourning .
the basic form of palliative care is home care and is exercised by a doctor , nurse , psychologist , physiotherapist and social worker mainly .
the patient has the right to use medical services offered by the family doctor and other specialists but due to low mobility and frequent contact with the hospice physician chooses the latter [ 24 , 26 ] .
there was a decrease in the number of deaths at home in the second half of the twentieth century .
the number of cancer patients dying at home decreased from 37% in 1965 to 27% in 1987 . according to the office for national statistics
58% of deaths occur in hospitals , 18% at home , 17% in nursing homes , 4% in hospices and 3% in other places . according to yao and colleagues dying at home
they conducted research on 374 patients dying from cancer and compared a group of patients dying from cancer at home with a group of patients dying in a hospital palliative care unit .
they concluded that the comfort of patients dying at home was higher compared to patients dying in hospital .
however , the assessed level of physical comfort before death at home was lower compared to the comfort of the hospital . early integration of palliative care to standard anticancer therapy can contribute to better preparation of the patient for death .
the authors evaluated the quality of death and dying by the quality of death and dying ( qodd ) questionnaire .
it consisted of 31 items , focused on the last seven days of life of the dying person .
a family member assessed the quality of death and dying on a scale from 0 ( terrible ) to 10 ( almost perfect ) .
the results showed that the quality of dying was higher in the environment known to the patient . according to hunt ,
the elements of a good death include : control of physical symptoms , acceptance of the disease and its diagnosis , maintaining hope , satisfaction with life and peaceful death at home .
mcneil suggests that patients want to die at home because they intend to have control over their lives in the home environment . on the other hand
the head of the medical unit of palliative care should be a physician certified in palliative care .
due to the insufficient number of professionals in this field this function can also be served by physicians of another speciality but experienced in palliative care and having completed relevant courses .
the nurse employed in the palliative care should be specialized in this area or complete a qualification course ( or perfecting of palliative care ) .
other members of the multidisciplinary team are recommended to have received training in palliative care making work with the patient and her / his family easier .
home hospices are an organizational form of palliative care where patients staying at home may use equipment rented from the hospice .
palliative care units should be located so there is one for two or three counties .
they allow medical procedures to be carried out that can not be done at home , and ensure specialized care .
outpatient palliative care is for patients in good general condition , but with limited mobility .
day care centres are for patients who permanently reside in their homes and are visited one or more times a week during the day .
a home hospice for children provides palliative care for children with life limiting illnesses living in homes .
one concept of the practice of palliative medicine is to make it an integral part of oncology . for development of this model ,
the proposals of the european society for medical oncology ( esmo ) , according to which palliative care and supportive treatment are defined as oncologists obligation and duty , can be considered .
the esmo draws attention to the need to implement the so - called philosophy of continuity of care , professional assistance both medical and nursing , integration of oncological and palliative treatment , and meeting of physical and existential needs .
a document entitled better palliative care for older people edited by davies and higginson . was published in 2004 , under the auspices of the european section of the who . according to the report
in addition , the document emphasizes the development of home care , which helps to avoid many unnecessary hospitalizations .
attention is drawn to assuring holistic care , respect for patient autonomy and support for caregivers .
in poland , 90 thousand people die from neoplastic disease each year , 55.3% in hospital and 44.2% at home .
due to the aging population and due to the expected increase in morbidity and mortality from cancer , the number of people requiring palliative care will increase .
therefore , it is important to ensure good quality care for these people , in accordance with the standards of the world health organization .
palliative medicine has been a clinical specialty for doctors and nurses since 1999 . under - funding
it has concerned in - patient institutions , which led to elimination of individual palliative care wards in 2008 .
a project on regulation of standards in palliative care was submitted to the ministry of health in 2004 .
it still has not been put into practice . additionally , in many provinces palliative care units are located in old buildings that require renovation .
there are not enough beds for patients and there are no funds for renovation and modernization .
the majority of outpatient palliative clinics make a financial loss , and contracts with the nfz ( national health fund ) are insufficient .
these are patients who not only suffer from pain and other symptoms associated with disease , but are also burdened with additional disorders . in poland , according to the law on universal health insurance , palliative care is financed from public funds as a separate provision of health .
palliative care is financed by the national health fund in the scope of : palliative home care team / home hospice , palliative medicine ward / in - patient hospice , home hospice for children and palliative care outpatient clinic .
hospital support teams and palliative day care centres are not funded by the nhf , hence the small number of them in the country [ 24 , 26 ] . in per capita terms
the amount of expenditures from the national health fund for palliative care remained constant in 20052008 and was 3.53 pln per patient .
this amount increased in the second half of 2008 ( 5.54 pln ) and in 2009 ( 6.73 pln ) .
palliative care units also functioned through additional sources of financing such as funds derived from local governments and from ngos ( associations and foundations ) .
the implementation of the national cancer control programme is expected to integrate palliative care with oncology in poland .
the introduction of a hospital support team in all oncological hospitals was considered an important element .
its task is to ensure the introduction of palliative care and nursing care at an early stage of neoplastic disease , reduce patient distress in the hospital , and facilitate a smooth transition from hospital to home care .
| neoplastic diseases are among the most common causes of death .
the quality of life in neoplastic disease depends on the type of neoplasm , level of progression , location , treatment possibilities and prognosis .
cancer reduces the quality of life at the advanced stage of disease . at this time
patients feel pain and suffering .
palliative care is used in the terminal phase of neoplastic disease .
it includes overall care of an incurable patient and her / his family .
the main objective of palliative care is meeting somatic and psycho - social requirements .
recently , more and more physicians dealing with oncological patients are moving away from treatment of the patient like an object .
they pay attention to a subjective approach to treatment outcomes that are felt by the patient .
the model of medicine is becoming a holistic one and during examination physicians pay attention to the patient 's physical and mental state , economic condition , social situation , feelings or lack of complaints more often .
research on quality of life is becoming a vital part of medical examination . |
the united states department of defense and department of veteran affairs are dedicated to providing superior rehabilitation care for veterans and service members who have suffered combat - associated traumatic limb loss .
current literature reports that 70% of amputees with multiple limb loss are bothered by sweating and skin irritation inside of the prosthesis socket .
we present a review of the literature examining the effectiveness of botulinum toxin a ( btx - a ) and btx - b for the treatment of hyperhidrosis related to prosthesis use .
while both btx - a and btx - b are approved by the food and drug administration ( fda ) , indications for use are limited .
hyperhidrosis continues to be a significant barrier to prosthesis comfort , and treatment with btx has the potential to address this concern .
a review of the literature was conducted using the pubmed database , focusing on hyperhidrosis treatment after a traumatic limb amputation .
we used the key search words : btx ; hyperhidrosis ; amputation ; trauma - related amputation ; prosthesis comfort .
articles discussing hyperhidrosis treatment for axillary , palmar , plantar and amputations secondary to chronic medical conditions were excluded .
botulinum toxin a is currently approved by the fda as botox ( allergan , inc . ,
irvine , california , usa ) supplied in 50 and 100 unit vials , and dysport ( ipsen , berkshire , united kingdom ) supplied in 300 and 500 unit vials , to treat cervical dystonia , severe primary axillary hyperhidrosis , strabismus , blepharospasm , and for temporary improvement of moderate to severe glabellar lines .
the benefits of using btx - a for these conditions is well - established and it has few adverse effects at their respective therapeutic doses , which range from 20 to 360 units .
the most common adverse effects reported are muscle weakness , fatigue , flu - like symptoms , dry mouth , dizziness , discomfort at the injection site and skin rash
. large volume injections of btx - a > 600 units have been associated with systemic weakness related to injection dose and frequency , which should be a consideration in the treatment of the residual limb hyperhidrosis .
current literature emphasizes the positive effects of btx - a on pain perception , itch and inflammation while simultaneously producing an anhidrotic effect . a study conducted by charrow et al
. found that injections of btx - a successfully reduced residual limb hyperhidrosis and improved prosthesis fit and function when evaluated three weeks after treatment . in this study , 300 - 500 units of btx - a at a dilution of 100 units in 1 ml of 0.9% isotonic saline were injected intradermally with 2 - 3 units at 1 cm intervals in a circumferential pattern on the skin covered by the prosthesis socket .
this approach however , did not have any effect on the residual limb pain ( rlp ) or phantom limb pain ( plp ) .
however , jin et al . demonstrated in three cases that injection of btx - a at 200 , 300 , or 500 units using electromyographic guidance and targeting areas of the residual limb where strong fasciculations were present achieved marked improvement in rlp and plp lasting up to three months .
three separate case studies utilized a starch - iodine test to identify hyperhidrotic areas on a residual limb , then injected btx - a at 100 u in 5 - 10 unit aliquots , or 300 units in 25 units aliquots .
in all three reports , btx - a was diluted in preservative - free saline and produced anhidrotic effects lasting three months .
because our facility is a government - funded hospital with extensive medical coverage for military personnel , poor prosthesis satisfaction due to hyperhidrosis is the only indication needed for treatment . while large volume injections can be costly
, the literature has shown that improving prosthesis comfort is directly correlated with an improved quality of life .
to inject btx - a at 1 - 2 cm intervals in a grid - like pattern over a surface area of 600 cm would require over 140 intradermal injections , typically achieved with a 30-gauge needle .
the procedure lasts up to 30 min and is criticized as painful . a recent study by torrisi et al . investigated the use of pocketed microneedles ( pmn ) as an intradermal delivery system for btx - a .
the width of the pmn used in this study is 340 m , which could serve as a less invasive administration method of btx - a in hyperhidrotic areas .
botulinum toxin type b , supplied in 2500 , 5000 , and 10,000 units vials is approved by the fda as myobloc ( solstice neurosciences , inc .
the use of btx - b for the treatment of palmar hyperhidrosis was deemed effective by baumann et al . and further studied by kern et al . in the treatment of the residual limb hyperhidrosis for lower limb amputees .
btx - b administered in a low dose is believed to have a higher affinity for sympathetic nerve endings and better diffusion than btx - a .
furthermore , btx - b and was found to be effective in reducing residual limb sweating in nine lower limb amputees .
treated nine lower limb amputees with 1750 units of btx - b injected intracutaneously using a 27-gauge needle ( 20 injection sites 2 - 4 cm apart ) .
in addition to subjective identification of hyperhidrotic areas , a starch - iodine test was used on six participants , to help guide injection locations .
study reported a significant reduction in residual limb sweating and a significant improvement in use of the prosthetic device , duration of use and quality of life evaluated 4 weeks and 3 months after treatment .
btx - b also decreased rlp and plp as well as improved quality of life and prosthesis use .
reports that btx - b injections in muscular trigger points decreased rlp and involuntary movements of the stump for 4 - 12 weeks , which was dependent on the btx - b dose and location of amputation .
two of the four patients had a trauma - related amputation , and all found the injections very painful .
current literature investigating the use of btx to treat hyperhidrosis in trauma - related amputations is limited .
however , current case studies all report positive outcomes related to treating hyperhidrosis with either btx - a or btx - b .
hyperhidrosis , discomfort , and skin irritation related to prosthesis use in trauma - related limb loss remains a topic deserving of more attention as a larger , double - blind , placebo - controlled study evaluating the efficacy of btx - a and btx - b in treatment . | hyperhidrosis - related to prosthesis use in patients who have suffered a traumatic limb amputation presents itself as a barrier to comfort , prosthesis use and overall quality of life .
this review intends to encourage dermatologists to consider the use of botulinum toxin a or b for the treatment of hyperhidrosis in the residual limb and may serve as a stimulus for a modern , in - depth , and more comprehensive study .
a review of the literature was conducted using the pubmed database , focusing on hyperhidrosis treatment after traumatic limb amputation .
articles discussing hyperhidrosis treatment for amputations secondary to chronic medical conditions were excluded .
seven case studies published over the last 12 years have demonstrated positive outcomes of this treatment strategy .
overall , there is little data examining this topic and current publications focus primarily on small case series .
a larger , double - blind , placebo - controlled study would likely benefit veterans , service members , and civilians . |
this retrospective review included 49 patients ( 51 cases ) who had undergone arthroscopic suture bridge repair for a full thickness rotator cuff tear between january 2007 and july 2007 .
the patients with the following conditions were excluded : partial thickness rotator cuff tear , the patients who required tenotomy or tenodesis for treating the long biceps tendon , superior glenoid labrum injury that required fixation , acromioclavicular arthritis that required excision of the distal end of the clavicle , advanced glenohumeral arthritis , anterior instability of the shoulder , nerve injury and previous shoulder joint surgery .
there were 25 males ( 27 cases ) and 24 females ( 24 cases ) with an average age of 57.1 years ( range , 36 to 75 years ) .
thirty - nine cases involved the dominant shoulder and 12 cases involved the non - dominant shoulder .
the mean follow - up period was 15.4 months ( range , 12 to 18.3 months ) .
the size of the tear was measured along the longest axis by using probes during surgery and the tear sizes were categorized into small ( < 1 cm ) , medium ( 1 cm to 3 cm ) , large ( 3 cm to 5 cm ) and massive ( > 5 cm ) tears according to the classification of deorio and cofield.8 ) all of the physical examinations were performed the day before surgery and during the follow - up period .
muscle strength tests were performed using a nottingham mecmesin myometer ( mecmesin co. , nottingham , uk ) and the values were recorded in kilograms ( kg ) .
maximum elevation strength was measured with the arm elevated to 90 in the scapular plane and maximum external rotation strength and maximum internal rotation strength were measured with the arm in the neutral position . regarding the range of motion , forward elevation , external rotation with the arm in a neutral position , external and internal rotation with the arm at 90 abduction and posterior internal rotation and abduction were all measured before surgery and at the last follow - up . for clinical assessments , the constant score9 ) and the university of california at los angeles ( ucla ) score were measured and the patients ' satisfaction was also evaluated .
all of the operations were performed by the same surgeon with the patients in the beach - chair position .
passive range of motion and the levels of anterior , posterior and inferior translation were examined with the patient under anesthesia .
after preoperative skin preparation , a posterior portal was established 2 cm inferior and 1 cm medial to the posterolateral corner of the acromion and a diagnostic arthroscopy was performed through this portal . when the presence of rotator cuff tear was identified and a lesion of the long biceps tendon was also observed , the arthroscope was inserted through the posterior portal to the subacromial space , and a lateral portal was additionally created . through this portal , the pattern of the rotator cuff tear in the subacromial space was observed .
if severe fibrillation was observed inferior to the acromion , except when the acromion was seen as being flat on the preoperative radiographs , the patient was young or the rotator cuff tear was caused by a definite trauma , then acromioplasty was performed based on the plain radiographs and arthroscopic findings .
after acromioplasty , a posterolateral portal was created as a viewing portal in the middle of the imaginary line connecting the posterior portal and the lateral portal.10 ) a shaver was used to debride the torn edges of the rotator cuff and the greater tuberosity , and a high speed burr was used to expose the cancellous bone .
the torn rotator cuff was pulled with a grasper and a proper suture site was determined .
a spinal needle was inserted from the lateral edge of the acromion to determine the proper position and angle ( immediately lateral to the joint cartilage ) for insertion of a bone punch . through a 5 mm incision ,
a bio - cork screw suture anchor ( arthrex , naples , fl , usa ) was inserted into the planned site .
the number of the anchors used was 1 or 2 depending on the tear size .
then , through the 3 sister portals10 ) or a modified neviaser portal , a suture was passed through the rotator cuff as proximally as possible using a suture hook ( linvatec , largo , fl , usa ) or a banana suturelasso ( arthrex ) and the suture limb that was loaded onto the inserted suture anchor was passed using the shuttle - relay .
the suture limbs were spaced the same distance apart and revo knots , one of the non - sliding knots , were tied in a horizontal mattress suture pattern .
suture bridge repair was then carried out by fixating one limb from each anchor to the lateral aspect of the greater tuberosity using a pushlock anchor ( arthrex ) .
postoperatively , a self - controlled analgesia device was used for all patients at their request .
pendulum exercises and passive forward flexion were started immediately after surgery and passive exercise was performed until the 6th postoperative week to restore the normal range of motion .
the pre- and postoperative clinical outcomes were compared using paired t - tests and wilcoxon signed rank tests .
the mann - whitney test was used to assess differences regarding gender , age , range of motion and muscle strength in the groups , as divided according to the tear size , and the association between the preoperative global fatty degeneration index ( gfdi ) and the final outcome .
correlation between the preoperative tear size and the retear rate was assessed using pearson 's chi - square test .
statistical analyses were performed using spss ver.12.0 ( spss inc . , chicago , il , usa ) with a 95% confidence interval .
this retrospective review included 49 patients ( 51 cases ) who had undergone arthroscopic suture bridge repair for a full thickness rotator cuff tear between january 2007 and july 2007 .
the patients with the following conditions were excluded : partial thickness rotator cuff tear , the patients who required tenotomy or tenodesis for treating the long biceps tendon , superior glenoid labrum injury that required fixation , acromioclavicular arthritis that required excision of the distal end of the clavicle , advanced glenohumeral arthritis , anterior instability of the shoulder , nerve injury and previous shoulder joint surgery .
there were 25 males ( 27 cases ) and 24 females ( 24 cases ) with an average age of 57.1 years ( range , 36 to 75 years ) .
thirty - nine cases involved the dominant shoulder and 12 cases involved the non - dominant shoulder .
the mean follow - up period was 15.4 months ( range , 12 to 18.3 months ) .
the size of the tear was measured along the longest axis by using probes during surgery and the tear sizes were categorized into small ( < 1 cm ) , medium ( 1 cm to 3 cm ) , large ( 3 cm to 5 cm ) and massive ( > 5 cm ) tears according to the classification of deorio and cofield.8 )
all of the physical examinations were performed the day before surgery and during the follow - up period .
muscle strength tests were performed using a nottingham mecmesin myometer ( mecmesin co. , nottingham , uk ) and the values were recorded in kilograms ( kg ) .
maximum elevation strength was measured with the arm elevated to 90 in the scapular plane and maximum external rotation strength and maximum internal rotation strength were measured with the arm in the neutral position .
regarding the range of motion , forward elevation , external rotation with the arm in a neutral position , external and internal rotation with the arm at 90 abduction and posterior internal rotation and abduction were all measured before surgery and at the last follow - up .
for clinical assessments , the constant score9 ) and the university of california at los angeles ( ucla ) score were measured and the patients ' satisfaction was also evaluated .
all of the operations were performed by the same surgeon with the patients in the beach - chair position .
passive range of motion and the levels of anterior , posterior and inferior translation were examined with the patient under anesthesia .
after preoperative skin preparation , a posterior portal was established 2 cm inferior and 1 cm medial to the posterolateral corner of the acromion and a diagnostic arthroscopy was performed through this portal . when the presence of rotator cuff tear was identified and a lesion of the long biceps tendon was also observed , the arthroscope was inserted through the posterior portal to the subacromial space , and a lateral portal was additionally created . through this portal , the pattern of the rotator cuff tear in the subacromial space was observed .
if severe fibrillation was observed inferior to the acromion , except when the acromion was seen as being flat on the preoperative radiographs , the patient was young or the rotator cuff tear was caused by a definite trauma , then acromioplasty was performed based on the plain radiographs and arthroscopic findings .
after acromioplasty , a posterolateral portal was created as a viewing portal in the middle of the imaginary line connecting the posterior portal and the lateral portal.10 ) a shaver was used to debride the torn edges of the rotator cuff and the greater tuberosity , and a high speed burr was used to expose the cancellous bone .
the torn rotator cuff was pulled with a grasper and a proper suture site was determined .
a spinal needle was inserted from the lateral edge of the acromion to determine the proper position and angle ( immediately lateral to the joint cartilage ) for insertion of a bone punch . through a 5 mm incision ,
a bio - cork screw suture anchor ( arthrex , naples , fl , usa ) was inserted into the planned site .
the number of the anchors used was 1 or 2 depending on the tear size .
then , through the 3 sister portals10 ) or a modified neviaser portal , a suture was passed through the rotator cuff as proximally as possible using a suture hook ( linvatec , largo , fl , usa ) or a banana suturelasso ( arthrex ) and the suture limb that was loaded onto the inserted suture anchor was passed using the shuttle - relay .
the suture limbs were spaced the same distance apart and revo knots , one of the non - sliding knots , were tied in a horizontal mattress suture pattern .
suture bridge repair was then carried out by fixating one limb from each anchor to the lateral aspect of the greater tuberosity using a pushlock anchor ( arthrex ) .
postoperatively , a self - controlled analgesia device was used for all patients at their request .
pendulum exercises and passive forward flexion were started immediately after surgery and passive exercise was performed until the 6th postoperative week to restore the normal range of motion .
the pre- and postoperative clinical outcomes were compared using paired t - tests and wilcoxon signed rank tests .
the mann - whitney test was used to assess differences regarding gender , age , range of motion and muscle strength in the groups , as divided according to the tear size , and the association between the preoperative global fatty degeneration index ( gfdi ) and the final outcome .
correlation between the preoperative tear size and the retear rate was assessed using pearson 's chi - square test .
statistical analyses were performed using spss ver.12.0 ( spss inc . , chicago , il , usa ) with a 95% confidence interval .
the mean vas score at rest decreased from 2.2 ( 0 to 7 ) preoperatively to 0.23 ( 0 to 2.5 ) postoperatively ( p < 0.001 ) .
the mean vas score during motion improved from 6.3 ( 2 to 9 ) preoperatively to 1.8 ( 0 to 7.5 ) postoperatively ( p < 0.001 ) .
the mean range of active forward flexion increased from 138.4 preoperatively to 154.6 postoperatively and the mean range of passive forward flexion improved from 143.4 to 161.9 ( p = 0.04 , 0.009 ) .
the mean external rotation in the neutral position was 50.4 preoperatively and 42.5 postoperatively ( p = 0.052 ) .
the mean external rotation at 90 abduction was 70.7 preoperatively and 78.3 postoperatively and the mean internal rotation at 90 abduction was 63.4 preoperatively and 47.5 postoperatively ( p = 0.06 , < 0.001 ) .
the mean internal rotation behind the back was t12 preoperatively and t10 postoperatively ( p = 0.021 ) ( table 1 ) .
the mean muscle strength during forward flexion increased from 4.9 kg preoperatively to 6.0 kg postoperatively , during external rotation in the neutral position from 6.5 kg to 6.9 kg ( p = 0.038 , 0.383 ) , and during internal rotation in the neutral position from 7.8 kg to 8.6 kg ( p = 0.265 ) .
the mean constant score9 ) improved from 73.2 ( range , 44 to 88 ) preoperatively to 83.7 ( range , 20 to 99 ) postoperatively ( p = 0.001 ) .
the mean ucla score increased from 18.2 preoperatively to 29.7 at the last follow - up ( p < 0.001 ) and there were 7 ( 13.7% ) excellent , 41 ( 80.4% ) good , and 3 ( 5.9% ) poor cases .
the mean patient satisfaction score at the last follow - up was 92.1 out of the total 100 points .
eight ( 16% ) small , 17 ( 33% ) medium , 9 ( 18% ) large and 17 ( 33% ) massive tears that were classified according to the classification of deorio and cofield8 ) were observed during arthroscopy .
the small and medium tears were combined into one group and the large and massive tears were combined into another group , and the clinical outcomes at the last follow - up were compared between the 2 groups .
the differences between the two groups regarding the preoperative age , gender , the level of pain at rest and during motion , and the muscle strength and range of motion during forward flexion did not show statistical significance ( p = 0.124 , 0.203 , 0.673 , 0.574 , 0.056 , and 0.903 , respectively ) .
no significant difference was found between the groups regarding the postoperative retear rate ( p = 0.109 ) .
muscle strength during forward flexion at the last follow - up was more satisfactory in the small to medium tear group than that in the large to massive tear group ( p = 0.029 ) , but no significant differences were found with regard to the other parameters ( table 2 ) . according to the gfdi that was evaluated preoperatively using magnetic resonance imaging ( mri),11 ) the patients were subdivided into those with 1 gfdi ( 21 cases ) and those with > 1 gfdi ( 30 cases ) .
the postoperative pain at rest and during movement remarkably decreased in both groups ( p < 0.001 ) .
no significant difference was found between the groups regarding the preoperative vas score for pain at rest and during movement ( vas ) ( p = 0.143 , 0.097 , respectively ) .
postoperatively , the vas score for pain at rest was notably low in the group with 1 gfdi ( p = 0.043 ) ( table 3 ) .
with regard to the range of motion , active and passive forward flexion and external rotation in the neutral position were greater preoperatively in the group with 1 gfdi than that in the other group ( p = 0.003 , 0.003 , and 0.013 , respectively ) , but no statistically significant difference was found between the groups postoperatively ( p = 0.075 , 0.396 , and 0.799 , respectively ) .
the muscle strength , the clinical test results and the postoperative patient satisfaction were better on average in the group with 1 gfdi both preoperatively and postoperatively , but the difference was not statistically significant ( p = 0.251 , 0.198 , and 0.348 , respectively ) mri scanning was performed in 46 of the 51 cases at an average of 7.2 months ( range , 6 to 9 months ) after surgery and retear was observed in 17 ( 36.9% ) of them : 2 ( 28.6% ) in the 7 patients with small tears , 4 ( 26.7% ) in the 15 patients with medium tears , 3 ( 33.3% ) in the 9 patients with large tears and 8 ( 53.3% ) in the 15 patients with massive tears .
the patients were divided into an anatomic restoration group and a retear group for comparisons .
the constant score9 ) at the last follow - up was 84.8 and 82.3 respectively and the ucla score was 29.9 and 28.7 respectively , showing no statistically significant difference between the groups ( p = 0.189 , 0.273 ) .
however , a significant difference was found between the groups regarding the preoperative fatty degeneration , which was severe in the retear group ( p = 0.048 ) .
the mean vas score at rest decreased from 2.2 ( 0 to 7 ) preoperatively to 0.23 ( 0 to 2.5 ) postoperatively ( p < 0.001 ) .
the mean vas score during motion improved from 6.3 ( 2 to 9 ) preoperatively to 1.8 ( 0 to 7.5 ) postoperatively ( p < 0.001 ) .
the mean range of active forward flexion increased from 138.4 preoperatively to 154.6 postoperatively and the mean range of passive forward flexion improved from 143.4 to 161.9 ( p = 0.04 , 0.009 ) .
the mean external rotation in the neutral position was 50.4 preoperatively and 42.5 postoperatively ( p = 0.052 ) .
the mean external rotation at 90 abduction was 70.7 preoperatively and 78.3 postoperatively and the mean internal rotation at 90 abduction was 63.4 preoperatively and 47.5 postoperatively ( p = 0.06 , < 0.001 ) .
the mean internal rotation behind the back was t12 preoperatively and t10 postoperatively ( p = 0.021 ) ( table 1 ) .
the mean muscle strength during forward flexion increased from 4.9 kg preoperatively to 6.0 kg postoperatively , during external rotation in the neutral position from 6.5 kg to 6.9 kg ( p = 0.038 , 0.383 ) , and during internal rotation in the neutral position from 7.8 kg to 8.6 kg ( p = 0.265 ) .
the mean constant score9 ) improved from 73.2 ( range , 44 to 88 ) preoperatively to 83.7 ( range , 20 to 99 ) postoperatively ( p = 0.001 ) .
the mean ucla score increased from 18.2 preoperatively to 29.7 at the last follow - up ( p < 0.001 ) and there were 7 ( 13.7% ) excellent , 41 ( 80.4% ) good , and 3 ( 5.9% ) poor cases .
the mean patient satisfaction score at the last follow - up was 92.1 out of the total 100 points .
eight ( 16% ) small , 17 ( 33% ) medium , 9 ( 18% ) large and 17 ( 33% ) massive tears that were classified according to the classification of deorio and cofield8 ) were observed during arthroscopy .
the small and medium tears were combined into one group and the large and massive tears were combined into another group , and the clinical outcomes at the last follow - up were compared between the 2 groups .
the differences between the two groups regarding the preoperative age , gender , the level of pain at rest and during motion , and the muscle strength and range of motion during forward flexion did not show statistical significance ( p = 0.124 , 0.203 , 0.673 , 0.574 , 0.056 , and 0.903 , respectively ) . no significant difference was found between the groups regarding the postoperative retear rate ( p = 0.109 ) .
muscle strength during forward flexion at the last follow - up was more satisfactory in the small to medium tear group than that in the large to massive tear group ( p = 0.029 ) , but no significant differences were found with regard to the other parameters ( table 2 ) .
according to the gfdi that was evaluated preoperatively using magnetic resonance imaging ( mri),11 ) the patients were subdivided into those with 1 gfdi ( 21 cases ) and those with > 1 gfdi ( 30 cases ) .
the postoperative pain at rest and during movement remarkably decreased in both groups ( p < 0.001 ) .
no significant difference was found between the groups regarding the preoperative vas score for pain at rest and during movement ( vas ) ( p = 0.143 , 0.097 , respectively ) .
postoperatively , the vas score for pain at rest was notably low in the group with 1 gfdi ( p = 0.043 ) ( table 3 ) . with regard to the range of motion , active and passive forward
flexion and external rotation in the neutral position were greater preoperatively in the group with 1 gfdi than that in the other group ( p = 0.003 , 0.003 , and 0.013 , respectively ) , but no statistically significant difference was found between the groups postoperatively ( p = 0.075 , 0.396 , and 0.799 , respectively ) .
the muscle strength , the clinical test results and the postoperative patient satisfaction were better on average in the group with 1 gfdi both preoperatively and postoperatively , but the difference was not statistically significant ( p = 0.251 , 0.198 , and 0.348 , respectively )
mri scanning was performed in 46 of the 51 cases at an average of 7.2 months ( range , 6 to 9 months ) after surgery and retear was observed in 17 ( 36.9% ) of them : 2 ( 28.6% ) in the 7 patients with small tears , 4 ( 26.7% ) in the 15 patients with medium tears , 3 ( 33.3% ) in the 9 patients with large tears and 8 ( 53.3% ) in the 15 patients with massive tears .
the patients were divided into an anatomic restoration group and a retear group for comparisons .
the constant score9 ) at the last follow - up was 84.8 and 82.3 respectively and the ucla score was 29.9 and 28.7 respectively , showing no statistically significant difference between the groups ( p = 0.189 , 0.273 ) .
however , a significant difference was found between the groups regarding the preoperative fatty degeneration , which was severe in the retear group ( p = 0.048 ) .
advances have been made in performing surgical rotator cuff repair and there are many recent studies showing excellent clinical outcomes.12 - 15 ) particularly , arthroscopy , which is associated with a good cosmetic appearance and rapid rehabilitation due to the minimal damages to adjacent structures , is employed in various medical fields .
it is widely recommended for the treatment of the shoulder because there is no need to detach the deltoid muscle when performing arthroscopy.13 ) the factors that appear to be determinants for retear after repair and postoperative recovery include the suture strength,4 ) the contact area and contact pressure at the tendon - bone interface,16 ) the tendon - bone interface motion,17 ) fatty degeneration of the rotator cuff muscles,18 ) the tear size , the bone quality of the humerus , the design and effect of the suture materials and the rehabilitation program 's propriety . in open repairs , suture techniques with superior holding power such as the mason - allen technique19 ) and transfixion suture are employed without difficulty .
however , they are not easy to perform in arthroscopic rotator cuff repair and other materials such as suture anchors should be used instead .
unfortunately , biomechanical studies have shown that the arthroscopic single - row suture anchor technique allows weaker fixation than the established transfixion suture does.17,20 ) the concept of footprint reconstruction was recently introduced and apreleva et al.21 ) evaluated the 3-dimensional structures of the rotator cuff insertion sites after repairs using various techniques and they described that the larger the interface was , the better was the potential for tendon - bone healing and the strength of the repaired tendon .
thereafter , several arthroscopic repair techniques that provide greater holding power , interface area and contact pressure have been developed and the arthroscopic suture bridge technique is one of them.22 - 24 ) while the arthroscopic suture bridge technique has been described in many biomechanical reports as being more effective for obtaining high initial fixation strength and greater interface area and pressure than the other suture methods , studies analyzing the clinical results of such repairs are rare.6,7,25 ) regarding the factors influencing the clinical outcome of rotator cuff repair , kim et al.1 ) reported that the final outcome was more dependent on the preoperative tear size rather than the surgical technique . with regard to the rotator cuff integrity and the shoulder function ,
some authors have documented that they could not find a clear correlation between them,22,26,27 ) while others suggested that great rotator cuff integrity would result in satisfying shoulder function.23,24,28,29 ) gazielly et al.23 ) associated the anatomical integrity of the rotator cuff and the clinical outcome : the larger the early tear size was the worse the clinical outcome was . in this current study ,
arthroscopic suture bridge repairs for various sizes of rotator cuff tears resulted in improvement in pain , range of motion and muscle strength , and the differences in the clinical improvement , except for muscle strength during forward flexion , were not statistically significant between the small and medium size tear group and the large and massive size tear group .
in addition , postoperative mri showed no differences between the groups regarding the recurrence rate ( p = 0.109 ) .
we attribute this to the anatomical integrity of the rotator cuff , which could be obtained with the arthroscopic suture bridge technique regardless of the preoperative tear size .
therefore , we believe that this clinical study confirmed the advantages of the arthroscopic suture bridge technique , and this technique has been previously established by many biomechanical studies : the firm , early fixation and high tendon - bone contact pressure provided by the repair method contributes to the repaired cuff 's integrity even in the cases of large size tears.5 - 7,25 ) preoperative fatty degeneration is known as an important factor for the anatomical integrity of the repaired rotator cuff . according to goutallier et al.,11 )
severe fatty degeneration was correlated with an unsatisfactory surgical outcome and a high retear rate .
similarly , radiological retears were identified in the patients who had severer fatty degeneration in our study .
however , the retear rate and preoperative fatty degeneration were not correlated with each other at a statistically significant level for the clinical tests , which is contrary to the study of goutallier et al.11 ) in our opinion , this is because the suture bridge technique was not as much affected by the level of preoperative fatty degeneration as the other methods . in this study
, we analyzed the final clinical results of the arthroscopic suture bridge technique for rotator cuff repair and we confirmed clinical improvements in the repaired shoulders regardless of the preoperative tear size and the level of fatty degeneration .
however , we think that studies involving a larger population , long - term follow - up and comparisons with other suture techniques should be conducted in the future to determine the magnitude of the contribution of the technique to the integrity of the shoulder and the clinical improvement .
the arthroscopic suture bridge technique for rotator cuff repair resulted in clinical improvement in pain , the range of motion and muscle strength regardless of the preoperative tear size and fatty degeneration , although radiologically detected retears were found in the patients with severer preoperative fatty degeneration .
this technique can be applied when a large tear has to be treated or when the established methods such as the single - row suture technique will not achieve satisfying results due to advanced fatty degeneration .
in addition , the clinical improvement that can be obtained with this method is expected to be less affected by the tear size and fatty degeneration . | backgroundthe purpose of our study is to evaluate the clinical results of arthroscopic suture bridge repair for patients with rotator cuff tears.methodsbetween january 2007 and july 2007 , fifty - one shoulders underwent arthroscopic suture bridge repair for full thickness rotator cuff tears .
the average age at the time of surgery was 57.1 years old , and the mean follow - up period was 15.4 months.resultsat the last follow - up , the pain at rest improved from 2.2 preoperatively to 0.23 postoperatively and the pain during motion improved from 6.3 preoperatively to 1.8 postoperatively ( p < 0.001 and p < 0.001 , respectively ) .
the range of active forward flexion improved from 138.4 to 154.6 , and the muscle power improved from 4.9 kg to 6.0 kg ( p = 0.04 and 0.019 , respectively ) .
the clinical results showed no significant difference according to the preoperative tear size and the extent of fatty degeneration , but imaging study showed a statistical relation between retear and fatty degeneration .
the average constant score improved from 73.2 to 83.79 , and the average university of california at los angeles score changed from 18.2 to 29.6 with 7 excellent , 41 good and 3 poor results ( p < 0.001 and p = 0.003 , respectively).conclusionsthe arthroscopic suture bridge repair technique for rotator cuff tears may be an operative method for which a patient can expect to achieve clinical improvement regardless of the preoperative tear size and the extent of fatty degeneration . |
spinal tuberculosis ( tb ) is one of the oldest human diseases ; it has been found in egyptian mummies dating back 5000 years ; the first case of spinal tb was described by percival pott in 1779.1,2 in the developing countries , spinal tb is one of the primary causes of spinal deformity and paralysis . according to the latest global ( tb ) report by the world health organization , an estimated 9.0 million people developed tb and 1.5 million died from tb in 2013 alone.3 tb affects the spine in 3%5% of patients,4 and spinal tb
if patients are diagnosed early , they can be treated with the proper pharmaceutical drugs , such as antibiotics only .
early and definite diagnosis of this disease is not easy , as the disease progression is slow and insidious . due to this difficulty
, many patients in the early stages of the disease receive treatments , such as nonsteroidal anti - inflammatory drugs , physical therapy , or a corset ( spinal support ) , prior to correct diagnosis.6,7 a positive skin test and elevated erythrocyte sedimentation rate ( esr ) may be useful for diagnosing spinal tb , biopsy evaluation and dna amplification techniques ( polymerase chain reaction ) may also facilitate the diagnosis . for histopathological examination ,
formalin - fixed and paraffin - embedded tissue blocks of biopsied specimens are stained with hematoxylin
eosin.8 conventional radiography methods are used as first - step diagnostic methods , providing a good overview .
advanced imaging methods , such as magnetic resonance imaging ( mri ) , play an important role in detecting spinal tb earlier than other techniques and provide the possibility of earlier and more effective treatment before significant defects develop.9 three - dimensional computed tomography ( ct ) scans and mri reveal the involved vertebrae and attachments clearly.10 they can also exhibit the degree of intervertebral disk destruction , the scope of central lesions , the locations and number of cavities and abscesses , and spinal cord compression.11 mri and ct facilitate and allow the diagnosis of spinal tb , but histopathological diagnosis remains essential.12,13 pharmacological therapy usually consists of triple - drug antituberculous chemotherapy ( p - aminosalicylic acid , streptomycin , and isoniazid ) and plays a main role in tb treatment,12 if the lesion is without complications and limited to the vertebrae .
some studies14,15 have reported the worsening of existing symptoms or the appearance of new lesions in patients who initially responded well to antituberculous therapy . however , with the appropriate indications , surgery is considered superior for preventing neurological deterioration , maintaining stability , and early recovery.1618 surgical treatment of spinal tb aims at abscess debridement , which involves removing purulent necrotic tissues from normal tissue , spinal cord decompression , permanent spinal stabilization , and preventing or correcting deformity . considering the serious burden caused by the high cost of medical treatment and surgical trauma , early diagnosis and treatment to avoid multivertebral destruction are critical to improve the outcomes in spinal tb.11
spinal tb is one of the most challenging diseases for surgeons to treat , and some guidelines are needed for appropriate decision making and treatment .
currently , there are few widely accepted classification systems based on objective data that can guide the selection of the proper treatment approach for patients with spinal tb . in 2008
, oguz et al19 developed a classification system ( gulhane askeri tp akademisi [ gata ] ) for spinal tb based on seven clinical and radiological criteria ( abscess formation , disk degeneration , vertebral collapse , kyphosis [ unnatural curvature of the upper back that creates a hunchback appearance ] , sagittal index , instability , and neurological problems ) .
they also recommended specific techniques for each type . per the gata classification system , spinal tb
is divided into three types ( ia / b , ii , and iii ) using the abovementioned criteria ( table 1 ) .
surgery is recommended for type ib ( abscess formation , one or two level disk degeneration , no collapse , and no neurologic deficit ) , type ii , and type iii patients with or without neurological deficit .
analgesic therapy alone can not prevent the extensive destruction of vertebral bone and disk material .
after cold abscess and two - level disk degeneration , immediate drainage along with medical therapy can protect the patient from vertebral collapse .
as long as the treatment plan is fully prepared , the surgical option can achieve a satisfactory curative effect in treating spinal tb , despite some complications .
we believe that the appropriate treatment method should be implemented at the early stage of this disease and that the gata classification system can be considered as a practical guide for spinal tb treatment planning in all countries .
current treatment modalities ( medical and surgical ) have improved outcomes in the management of spinal tb , even in patients with neurological deficits and spinal deformities
. however , there are various surgical or conservative treatment options , and heterogeneous outcomes have been described , which render the decision - making and selection of specific treatment options by surgeons difficult .
future investigations and publications require clear definitions of spinal tb to help guide the appropriate decisions and treatment by surgeons . | spinal tuberculosis ( tb ) is a significant form of tb , causing spinal deformity and paralysis .
early diagnosis and treatment are crucial for avoiding multivertebral destruction and are critical for improving outcomes in spinal tb .
we believe that appropriate treatment method should be implemented at the early stage of this disease and that the gulhane askeri tp akademisi classification system can be considered a practical guide for spinal tb treatment planning in all countries . |
photochromic molecules
from the spiropyran family are reversibly
switched between the spiro form ( sp ) , displaying absorption only in
the uv region , and the merocyanine form ( mc ) , absorbing light also
in the visible region , using light of appropriate wavelengths .
although the color change is the most widely
recognized feature for spiropyrans and photoswitches in general , it
is by no means the only property that changes upon isomerization .
additional examples are the redox energies , molecular structure , and charge distribution , to mention a few .
altogether , the light - induced
changes in these and other properties have been harnessed for applications
in , for example , the photocontrol of biological functions , bioimaging , optical signal processing , and photoswitching in general , as well as in chemosensing . in many of these situations ,
aqueous media is required and , hence ,
also spiropyran derivatives that are readily dissolved in water . as
the spiropyran backbone per se has very poor water solubility , covalent
attachment of solubilizing groups , or supramolecular complex formation
with water - soluble hosts
our approach has been to covalently attach positively charged alkylamino-
or amidine groups to the spiropyran photoswitch .
these compounds have
been studied in the contexts of photo- and ph controlled dna - binding , photoinduced cytotoxicity , membrane
interactions , and supramolecular complex
formation .
owing to the potential applicability
in diverse fields , the ring - opening mechanism , conformational
distribution , and photochemical properties of various derivatives have also been addressed by theoretical investigations .
although the spiropyrans represent a very versatile class of photochromic
compounds with several promising candidates for future use in biological
applications , the behavior in aqueous media is relatively unexplored .
here , we present a comprehensive model of all processes relevant for
the interconversions between the different species ( sp , mc , and the
respective protonated forms ) including the thermal and photoinduced
isomerization processes , as well as the undesired hydrolysis reaction .
to support experiments , the hydrolytic degradation of the mc form
was also investigated by theoretical calculations , using both quantum
mechanics ( qm ) and combined quantum mechanics / molecular mechanics
( qm / mm ) models employing density functional theory .
these addressed
several mechanisms for both the protonated and the nonprotonated forms
of the molecule and also the effect of water on the barrier heights ,
with final energies obtained at the b3lyp/6 - 311++g(2d,2p ) level of
theory .
we hope that the results from this study will be of help to
others in the design of spiropyran derivatives for various applications
where aqueous media is a requirement .
the synthesis of 1,2,4 , and 6(7 ) have been described earlier , whereas the synthesis
of 3 and 5 are outlined in the supporting information .
the ring - opened forms
( mc and mch ) were prepared by heating the sp isomer in
an aqueous solution at ph 1 until the sample was fully converted to
the mch form ( ca . 5 min ) . for mc ,
the sph form was
prepared by dissolving sp in aqueous solution followed by acidification
with conc .
the absorption
measurements
were carried out on a carybio 50 uv / vis spectrometer equipped with
a varian pcb 1500 water peltier system thermostat for temperature
control .
the visible light was generated by a 500 w xe lamp equipped with a
hot mirror ( a = 1.8 at 900 nm ) to reduce the ir intensity
and suitable optical filters .
for quantum yield determinations , an
interference filter in the visible region was used ( see supporting information for details ) .
the uv light
was generated by a uvp lamp model uvgl-25 ( 254 nm , 700 w / cm ) .
the time - based absorption measurements at ph 410
were performed in buffered solutions with 10 mm na2hpo4/nah2po4 set to the respective ph . at
ph 3 and lower ,
all quantum chemical calculations
were performed using the gaussian 09 software package . to address the reaction mechanism of hydrolysis ,
two models were used .
the reaction steps of the minimum energy path
and the alternative reaction paths were addressed using a smaller
qm model which included the initial merocyanine and one explicit water
molecule ( qm(1w ) ) ( see figure s6 in the supporting
information ) .
all the minima and transition states ( tss ) for
qm(1w ) were optimized using becke s three parameter
parr
correlation functional ( b3lyp ) with the
6 - 31+g(d , p ) basis set .
this model considered solvent effects of water
using the integral equation formalism for the polarizable continuum
solvent model ( iefpcm ) . to investigate
potential effects of explicit water molecules on the barrier heights
of the most important tss , an oniom ( our own n - layered integrated
molecular orbital and molecular mechanics ) integrated qm / mm method model was used , in which six water molecules
and the merocyanine were included in the qm layer , surrounded by a
40 box of explicit water molecules in a b3lyp/6 - 31g(d):amber
setup ( oniom(6w ) ) . to ensure the relaxation of water equilibrated
around mc , the final oniom(6w ) model
initially , the qm / mm model was fully minimized with only the mc molecule
included in the qm layer .
this was followed by an optimization with
the water molecule closest to ca ( for labeling of atoms ,
see scheme 1 ) included in the qm layer , and
all water molecules farther than 15 from the mc molecule being
frozen .
finally , five additional water molecules were chosen ( the
five closest to the ca atom ) , resulting in three above
and three below the plane of the merocyanine molecule ( see figure
s6 in the supporting information ) .
this
way , the potential stabilizing contribution of water molecules from
both sides of the mc molecule could be followed . for the qm layer
atoms , charges were determined using the merz singh
kollman
scheme on the qm(1w ) model , and for the
remaining five water molecules the charges were determined after initial
minimization .
our focus was on the mc reactant state
and on the three critical tss , tsi , tsii , and tsiii , which were subject to further calculations .
all critical points obtained for qm(1w ) , and the above selected
ones for oniom(6w ) , were followed by second derivative calculations
at the same level of theory as optimizations were performed .
these
were used to determine the nature of the optimized critical point
( minimum or ts ) , to obtain both zero point energies and thermal contributions
to the energy , and entropy contributions to free energies within the
harmonic approximation . in the case of qm(1w ) , for iii and tsiv the initial reactant consists practically
of two molecules coordinated
only by one small group from each , which resulted in convergence problems
with the molecular fragments rotating around the intermolecular axis .
therefore , convergence was achieved by constraining the relative orientation
of the fragments for the above two critical points .
this led to an
additional imaginary vibrational frequency for both calculations ,
not related to the reaction coordinate .
due to the small magnitudes ,
2i cm and 12i cm , respectively , the final energy values are
not significantly affected .
tsiii and the ts between
the ttt and the ttc conformers of
mch could not be located with the solvent model .
therefore ,
these two tss were optimized at the same level of theory as the other
critical points in the gas phase , followed by a single point calculation
which considered solvent effects .
for the two product states ( iv and hp ) , the transformations between different
coordination relative to each other were not considered .
the transition
state htsi starting from the ttc conformer
of mch was obtained using the loose convergence criteria
as implemented in the gaussian 09 software package .
electronic
energies were also calculated using point energy calculations
at the b3lyp/6 - 311++g(2d,2p ) and b3lyp/6 - 311++g(2d,2p):amber level
of theory for qm(1w ) and oniom(6w ) , respectively . for qm(1w ) critical
points iii , tsiv , iv , and hp consist of two separate molecules coordinated to each other ,
why the single point energy calculations with higher basis set also
serve the purpose of minimizing potential effects of basis set superposition
errors observed with smaller basis sets . for more details ,
see section theoretical calculations in the supporting information .
the primary objective of this work has been to investigate in detail
the various thermal , acido- and photochromic processes for the spiropyran
derivatives shown in figure 1 .
compounds 14 have a nitro substituent in the 6-position
of the benzopyran moiety ( c6 , see scheme 1 for labeling of relevant atoms discussed in the text ) .
these
compounds differ in the number of methylene units in the aminoalkyl - derived
tail attached to the indoline nitrogen ni ( three or five ) , as well as the number of methyl groups on the amino
nitrogen na ( two or three ) .
compounds 5 and 6 are equipped with a quaternary amine via a propyl tail and
come with an aldehyde and a cyano group on c6 , respectively .
the main reason for using different substituents on the benzopyran
ring was to vary the pka - value of the
phenolic oh group of the protonated mc isomer ( mch , see
scheme 1 ) .
a more
electron withdrawing substituent is expected to stabilize the negatively
charged oxygen oph of the nonprotonated mc isomer and ,
hence , decrease the pka - value . moreover , the variation of the substituents
at both the benzopyran ring and the indoline nitrogen ni effects several other thermal and photoinduced processes , as will
be described in detail below . in the following sections , the experimental
results ( spectra , kinetic traces , etc . )
will be shown only for 1 , whereas the corresponding data for 26 is collected in the supporting information .
structures of the closed spiro ( sp ) forms of the spiropyran derivatives
studied in this work .
scheme 1 shows
the relevant forms of 1 and the corresponding interconversion
pathways .
the spectra of the respective forms are shown in figure 2 ( see figure s1 in the supporting
information for corresponding spectra of 26 ) . framed : labelling of relevant
atoms discussed in the text .
the sp isomer
is converted to the mc isomer by uv - light exposure ,
and the reverse reaction is triggered by visible light . in the dark
,
the two isomers are interconverted by thermal processes . as opposed
to organic solvents , where the thermal equilibrium is shifted to virtually
100% sp , the rate constants for the thermal isomerization processes
sp mc and mc sp ( ko and kc in scheme 2 ) are comparable
in aqueous solution .
absorption spectra of 1sp ( ) , 1sph ( ) , 1mc ( ) , 1mch ( ) , and hp ( ) . at ph below
ca .
this is due to the highly polar nature of water
which stabilizes
the zwitterionic mc form .
it has also been suggested that hydrogen
bonding contributes to the mc form stabilization . upon acidification ,
protonation of the mc phenolate
oxygen oph leads to the formation of mch . here ,
the pka - value of this form is referred
to as pka . while this form
is readily converted
to sp using visible light , the corresponding thermal conversion is
not observed .
moreover , we suggest that the mch isomer
is stable also to hydrolytic degradation ( vide infra ) . upon further acidification , also the sp isomer is protonated .
we assign this species to sph , where the indoline nitrogen
ni of the sp isomer is protonated , with a pka - value referred to herein as pka .
this form displays
neither thermal nor photoinduced isomerizations , i.e. , it can only
be interconverted to the other forms after deprotonation to the sp
isomer .
it is obvious that the substituent
on c6 influences pka , whereas it has no effect on pka .
the ability to tune the pka - value by the choice of substituent has been proven useful
in many situations , including the ph - controlled dna - binding observed
in our laboratory .
furthermore , pka for 16 are significantly lower compared to spiropyran derivatives
without a positively charged functionality attached to the indoline
nitrogen ni . for example , pka of 1 , 2 , 5 , and 6 are almost two units lower compared to spiropyran derivatives
with a methyl group attached to ni ( 0.4 versus 2.3 ) .
as sph can not be converted to mc / mch by neither thermal nor photoinduced processes , this implies
that the ph range over which 16 maintain
their photochromic properties is significantly broadened . finally ,
one of the limiting factors for the application of spiropyrans
in aqueous medium is the hydrolytic instability of the mc form .
hydrolysis has been proposed to be initiated
by nucleophilic attack at the ene - iminium cation , followed by a retro - aldol
reaction yielding fischer s base and salicylaldehyde as hydrolysis
products ( hp ) . here ,
we suggest that the nonprotonated mc isomer is
the only form that is susceptible to hydrolysis and that water is
the major nucleophile involved in the reaction .
scheme 2 summarizes the kinetic
model with the respective rate constants for the thermal processes
and the pka - values for the protonated
forms .
the sections below
are organized as follows : first , the thermal
processes ( isomerization reactions and hydrolysis ) at ph 7 will be
described together with the photoinduced isomerization reactions .
at ph 7 ,
none of the protonated species are formed , i.e. , the involved
components are sp , mc , and hp . second , the corresponding results at
different ph will be presented for a selection of the derivatives .
our main objective in the design of 16 was to investigate the influence from the substituent on c6 in the benzopyran ring .
the results from ph 59 suggest that
water is the nucleophile in the hydrolysis reaction , rather than oh . in the ph - interval
01 , the equilibrium mc / mch is shifted to nearly 100% mch and the hydrolysis
reaction is virtually halted .
hence , our kinetic model in this ph
range contains sph , sp , and mch . based on
these results
. finally , we present computational results , which addressed
the hydrolysis mechanism in aqueous media for both the mc and the
mch forms that further strengthen the above notion .
figure 3 shows the time - dependent absorbance of 1mc reflecting the thermal interconversions of the dissolved sp and
the mc forms together with the subsequent hydrolysis of mc .
as the pka - values of the sph and the mch forms of 1 were determined
to 0.4 and 3.7 , respectively , the concentrations of the protonated
forms are negligible at ph 7 ( see table 1 for
the pka - values of derivatives 16 ) .
hence , our kinetic model at this ph includes
the species sp , mc , and hp .
, the kinetic model
shown in eq 1 was used to describe the kinetics
at ph 7.1 kinetic absorption trace of 1mc at 25 c
monitored
at 512 nm reflecting the thermal interconversions between sp , mc ,
and hp according to eq 1 .
the solid line is
the fitted trace using the biexponential expression in eq 2 .
inset : absorption spectrum recorded at t = 12000 min , clearly showing the residual absorption of 1mc centered at 512 nm . this kinetic model gives rise to a biexponential rate expression
for the concentrations of all involved species .
thus , the kinetic trace was fitted according to eq 2.2here , krise reflects
the rise time of the initial part of the kinetic trace in figure 3 , whereas kdecay is
the rate constant of the subsequent decay .
if ko + kc kh + k h , krise would have been the sum of ko and kc and , hence , the rise would
reflect the rate of the thermal equilibrium establishment between
sp and mc . here
, this assumption is not valid , and the analytic rate
expressions for [ sp ] , [ mc ] , and [ hp ] derived using the laplace transform
method were used ( see supporting information for the derived rate expressions ) .
it is obvious that
there are large variations in both the ratio ko / kc as well as
the sum ko + kc between the different derivatives , which in turn manifest itself
in differences in the hypothetical thermal equilibrium position [ mc]/[sp ]
and the time required to reach it .
80% mc at thermal equilibrium , whereas the corresponding number
for 6 is only 14% .
depending on the application , both
situations may be desired ( visible - light activation to the sp form
versus uv activation to the mc form ) .
as for minimizing the effect
of the hydrolytic degradation , a thermal equilibrium position enriched
in sp is preferred , as the concentration of the hydrolyzable mc isomer
is kept at a minimum .
the quantum yields of the photoinduced isomerization
processes and the photostationary distributions ( psd ) are also collected
in table 1 . the resistance toward photodegradation
no detectable decomposition was observed after 10 cycles ( see figure
s5 in the supporting information ) .
isomerization quantum yield for
the process sp mc using 254 nm uv - light .
isomerization quantum yield for
the process mc sp using visible light centered at 503 nm .
photostationary distribution
[ mc]/[sp ]
after the application of 254 nm uv - light .
the experiments and the
data analysis procedure at ph 7 described above were performed also
at ph 510 .
figure 4 shows the ph dependence
of the rate constants ko , kc , kh , and k
the extracted rate constants reflect the kinetic model
shown in eq . 1 , i.e. , none of the protonated
species sph or mch were considered . for 1
, this is a good approximation over the entire ph interval
510 as pka = 3.7
for this derivative , and hence , less than 5% exists as mch at ph 5 . for 5 and 6 ,
this implies
that around 25% mch is present at ph 5 , why the data is
only shown between ph 6 and ph 10 .
ph dependence of the thermal rate constants ko ( a ) , kc ( b ) , kh ( c ) , and k h ( d ) .
data shown for 1 ( ) , 5 ( ) ,
and 6 ( ) .
the rate constants for thermal opening and closing
( ko and kc in figure 4a , b ) show no significant variations
with ph .
this
is true also for the rate constant of hydrolysis mc hp ( kh in figure 4c ) up to
ph 9 , whereas an increase by a factor of ca . 2
this strongly suggests that water is the major
nucleophile in the hydrolysis reaction in the ph - independent interval
up to ph 9 , whereas the corresponding attack by oh is the rate determining step at higher ph .
the data for the corresponding condensation reaction ( reverse hydrolysis , k h in figure 4d ) shows that the process experiences a rate increase when going
from ph 8 to ph 7 .
we will , however , not analyze the condensation
reactions in the sections below , but instead focus on the hydrolysis
reaction .
the rate constants displayed in figure 4 are tabulated in table s1 in the supporting
information . at ph
significantly below
pka ( see scheme 2 and table 1 ) the mc / mch equilibrium is shifted to virtually only mch .
hence , sp was dissolved at the respective ph and the rise in the absorbance
of mch was monitored as a function of time .
the results
for 1 at ph 0 and ph 1 are shown in figure 5 . thermal formation of 1mch from 1sp via 1mc at ph 0 ( dashed line ) and ph 1 ( solid line ) .
the slower rise observed at ph 0 reflects the lower concentration
of the thermally isomerizable sp form . from the rise and
stay behavior it is obvious
that
the hydrolysis reaction is virtually halted at ph 0 and ph 1 .
therefore ,
the kinetic model in this ph regime is described by eq 3.3 in this ph region , however , the [ mc]/[mch ] equilibrium
is shifted to virtually 100% mch .
hence , the kinetic situation
reduces to a model including only
sph , sp , and mch according to eq 4.4the kinetic traces were fitted to a monoexponential
rate expression according to eq 5.5the equilibrium establishment between sp and
sph is extremely fast compared to ko .
hence , the apparent rate constant of thermal
opening , krise , is described by eq 6.6as pka for sph ( pka , see table 1 ) is known for all derivatives , the rate constant ko is easily extracted from the experimentally
fitted krise .
the ko - values at ph 0 and 1 were found to be : 4.0 10 min and 3.4 10 min for 1 , 1.3 10 min and 2.0 10 min for 5 , and 5.0 10 min and 5.3 10 min for 6 .
these values agree very well
with the corresponding values at ph 5 to ph 10 shown in figure 4a .
the fact that the rate constant of thermal opening
sp mc is virtually ph independent between ph 0 and 10 clearly
shows that there is no direct accelerated acid induced opening sp
mch , but that mch is formed via thermal
opening sp mc followed by protonation of mc .
furthermore ,
no hydrolysis is seen over 8000 min at ph 0 and 1 .
if oh would have been the nucleophile involved
in the rate determining step , the halted hydrolysis could have been
explained by the low oh concentration at these
ph values .
this is highly unlikely , however , as the rate of hydrolysis
does not vary significantly with the oh concentration
between ph 5 and 9 .
thus , we suggest that mch is not susceptible
to hydrolysis . this notion will be further supported by computational
means ( vide infra ) . at ph 24
,
a full kinetic model including all species and processes shown in
scheme 2 has to be applied .
we could not find
the analytic expression for this kinetic situation by the laplace
transformation method .
instead we used the experimental rate constants
derived at ph 5 and the respective pka - values to simulate the concentration profiles versus time for all
relevant species by numerical means .
these concentration profiles
were compared with the experimentally recorded absorption traces of
mc and mch at ph 24 . while the experimentally
obtained values of ko and kc at ph 5 together with pka and pka were
used in the simulations , the values of kh and k h were slightly adjusted
for each ph - value to improve the goodness of fit ( the experimental
values at ph 5 , kh = 1.8 10 min , k
h = 6.6 10 min , were
varied in the intervals 1.8 10 min 2.6 10 min and 0 6.6 10 min , respectively ) .
note that these adjustments are no
larger than the variations in the experimentally obtained values of kh and k h between ph 5 and ph 10 .
the results for 1 are shown
in figure 6 and the corresponding data for 5 and 6 is shown in figure s4 in the supporting information .
the results clearly show
that the kinetic model holds also at ph values where the interconversions
between all five species have to be taken into account .
experimentally
recorded absorbance traces for 1mc and 1mch at 25 c at ph 2 ( dash - dot , recorded
at 410 nm , mch ) , ph 3 ( dashed , recorded at 410 nm , mc
and mch ) , and ph 4 ( dotted , recorded at 512 nm , mc ) .
the
corresponding normalized traces derived from a simulation using the
kinetic model in scheme 2 and the rate constants
at ph 5 are also shown ( solid lines ) .
note that kh and k h were slightly
adjusted from the values determined at ph 5 ( see text for details ) . to support
experiments , the mechanism of hydrolysis of the mc isomer
the reaction steps were explored
using a qm model with one explicit water molecule considered , referred
to herein as qm(1w ) , whereas the effect of solvent molecules on the
barrier height was also addressed with a larger oniom model . here
, six water molecules were included in the
qm layer , further surrounded by water molecules treated by mm ( oniom(6w ) ) .
fortunately , in recent years several theoretical studies have focused
on various spectral properties of the sp mc conversion mechanism
of spiropyrans and related derivatives , which greatly helped in selecting
the optimal models and the applied theoretical method .
have analyzed in detail the effect of several density functionals
and continuum solvent models on relative energies of different conformers . based on these results and on previous tests
on hydrolysis reactions using mller
plesset ( mp2 ) calculations
as a reference , geometry optimizations for the
qm(1w ) model were performed at the b3lyp/6 - 31+g(d , p ) level of theory
with solvent effects of water considered by the iefpcm model .
final energies were obtained from point energy
calculations at the b3lyp/6 - 311++g(2d,2p ) level .
prior
to addressing the reaction steps , the initial reactant
conformer of mc was selected based on considering the four different
relative orientations of the p - nitro - phenolate and
the indolenium groups .
based on previous results and on our analysis ( see supporting
information ) , we concluded that the ttc conformer
is the major initial reactant and , hence , was used in the calculations .
the initial ttc conformer was optimized with four
alternative water positions close to ca and the lowest
energy conformer was selected to be the reactant state ( mc ) as shown in figure 7 .
a similar analysis
was performed for the protonated form , mch , where the
energetic distribution of the conformers showed that the ttt conformer is somewhat more stable than the ttc conformer .
however , the two conformers are separated by only a low energy transition
state ( ts ) as detailed in the supporting information , why we addressed the reaction paths starting from both ttc and ttt conformers for mch .
selected critical points along the minimum energy path starting
from the ttc conformer with the nucleophilic water
molecule coordinated on the molecule ( mc ) .
the obtained
critical points were qualitatively the same for the qm(1w ) and oniom(6w )
models .
relevant distances of the atoms participating in the hydrolysis
are displayed for the qm(1w ) and in parentheses for the oniom(6w )
with values in ngstrms . for more details , see tables 3 and 4 , and figures s6 and
s7 in the supporting information . to determine the most likely minimum
energy pathway of the reaction
these include two different paths starting from the neutral form ,
mc , and also two paths starting from the protonated form , mch .
the energy profile of the reaction was compared with the
free energy values derived back from the experimental rate constants
of hydrolysis shown in table 2 using classical
transition state theory . out of the reaction
pathways mentioned above , those which resulted in unlikely high energy
values for tss or for intermediate structures
see the experimental section , and theoretical calculations
in the supporting information .
the structure of the hydrolysis products
shows that the nucleophilic attack of the water molecule takes place
on the double - bond between the nitro - phenolate and the indolenium
fragments , with the water oxygen ( o ) coupling to carbon
atom ca ( for labeling of the atoms see scheme 1 and scheme 3 ) .
accordingly ,
in the initial reactant state mc , for both qm(1w ) and
oniom(6w ) models , the water molecule is coordinated on the phenolate
oxygen oph close to the central ca
cb double bond as shown in figure 7 and
figure s7 in the supporting information .
the reaction in qm(1w ) then proceeds via the first transition state
( tsi ) with a barrier of 26.5 kcal / mol into the first
intermediate ( i ) , in which oph becomes protonated
and the oh group from the water molecule ( o h )
forms a bond with ca . judging from the structure of the
hydrolysis products , the protons from the two oh
groups eventually
have to transfer to the opposite carbon , cb , which will
finally result in a methyl group on the indolenium fragment . from
intermediate
i , the overall reaction could in principle
proceed with a double proton transfer , where o
h
protonates cb , together with simultaneous o protonation by oph h ( see scheme 3 )
. however , the corresponding ts energy shown in figure 8 is above 40 kcal / mol , which renders this reaction
path very unlikely .
instead , the structure of intermediate i allows for a direct protonation of cb from oph
h , with a barrier height of 28.9 kcal / mol at tsii ( see table 3 and figures 7 and 8) . from this point , intermediate ii , the reaction proceeds with the breakup of the bond between
ca and cb via tsiii , with g = 26.5 kcal / mol . in intermediate iii
although at this point
the proton is still bonded to the oxygen , the extended conjugation
with the ring system renders the molecule in a planar conformation .
finally the protonation of cb takes place with a small
barrier from iii ( 19.4 kcal / mol ) through tsiv ( 20.7 kcal / mol ) , and the hydrolysis products are formed ( iv and hp ) .
considering reaction energetics of the minimum
energy path , there are three tss : tsi , tsii , and tsiii , which have similar relative energies where
the highest barrier corresponds to the transfer of the first proton
to cb from oph ( tsii ) with a free
energy of 27.2 and 28.9 kcal / mol at the b3lyp/6 - 31+g(d , p ) and b3lyp/6 - 311++g(2d,2p )
levels of theory , respectively .
considering the reactant and the product
states , mc and hp , the small relative energy
difference , 0.6 and 0.3 kcal / mol for the b3lyp/6 - 31+g(d , p )
and b3lyp/6 - 311++g(2d,2p ) levels , respectively , are in line with the
ratios of kh and k h displayed in table 2 .
this
is also in accordance with other similar hydrolysis reactions , where
reversibility was observed .
cb bond at tsiii , there are two molecular fragments , and the following
steps in the reaction involve a shallow ts in our investigation . consequently ,
the formation of the final two hydrolysis product molecules could
in principle also be achieved by proton transfers with other solvent
molecules that the present quantum chemical calculations do not consider . reaction
profile for hydrolysis of
energy values for the minimum energy pathway via
the phenolate mediated proton transfer ( solid line ) , and the reaction
pathway with direct protonation ( dashed line ) were obtained considering
solvent effects of water at the iefpcm - b3lyp/6 - 31+g(d , p ) level of
theory . to address the effects of further
explicit water molecules on the
barrier height with a different approach ,
the initial mc form and
the three high energy tss were also investigated in the oniom(6w )
model . despite major differences in the qm(1w ) and
oniom(6w ) models ,
the main structural parameters of the optimized mc , tsi and tsii critical points are very similar
as seen in figure 7 . the largest difference
can be observed for tsiii , where the distance between
ca and cb is 2.22 and 2.08 for
the qm(1w ) and oniom(6w ) models , respectively .
using iefpcm solvent model for water . using the iefpcm - b3lyp/6 - 31+g(d ,
p ) structure and iefpcm solvent model for water .
tsiii structure was
obtained in the gas phase at the b3lyp/6 - 31+g(d , p ) level of theory . in terms of energetics , the
oniom(6w )
free energy barrier heights
are all lower than the values for the corresponding tss in qm(1w ) .
when the e values presented in table 4 are compared for tsi and tsii , it is seen that they are similar for the two models .
thus , the
lower free energies arise from the more favorable relative entropy
terms and also from some smaller extra stabilization by the surrounding
water molecules .
however , in the case of tsiii the final
energies are significantly lower for the oniom(6w ) than for the qm(1w )
model . to understand the underlying reasons for this difference
, we
have analyzed the components of the oniom energies , which is briefly
discussed here .
the electronic relative energy of only the qm layer
is 31.3 kcal / mol for tsiii at the b3lyp/6 - 311++g(2d,2p )
level , which is 18.6 kcal / mol from the total oniom e of 13.3 kcal / mol obtained with the b3lyp/6 - 311++g(2d,2p):amber
setup shown in table 4 .
this clearly shows
that the different tsiii geometry with 2.08 cacb distance in the oniom(6w )
compared to the 2.22 as obtained for the qm(1w ) has no substantial
effect on the barrier height .
the excess stabilization of tsiii in the oniom(6w ) model is rather caused by the favorable contributions
of the water molecules in the mm layer : the coulomb and the van der
waals terms are , respectively , 9.8 and 8.7 kcal / mol more favorable
in tsiii compared to mc .
the relative
energies were obtained
at the iefpcm - b3lyp/6 - 311++g(2d,2p)//iefpcm - b3lyp/6 - 31+g(d , p ) level
of theory .
the relative
energies were obtained
with b3lyp/6 - 311++g(2d,2p):amber setup calculated on b3lyp/6 - 31g(d):amber
structures .
the major difference arising from considering explicit
water molecules is that for the qm(1w ) model there are three high
energy tss , while for the oniom(6w ) model there is only one ts found
with higher energy : tsii . for both models
this is the
highest ts with a 28.9 and 24.0 kcal / mol barrier height for the qm(1w )
and oniom(6w ) models , respectively .
although further refinement of
the energy values , e.g. , by investigating several qm / mm water configurations
or by obtaining conformational entropy contributions using md sampling
is beyond our scope , the obtained values can be used for a qualitative
comparison with the experimental rates .
free energy values can be
derived back from the experimental rate constants kh displayed in table 2 using classical
transition state theory .
these are 2324 kcal / mol ,
which is in close agreement with the theoretical values . to consider further paths
for hydrolysis
, we have also investigated the protonated form mch using the qm(1w ) model starting from both of its two lowest
energy conformers , ttc and ttt ( see
figure s8 , table s2 and text in the supporting
information ) . in the reactant form , referred to as mch , the oph
h group is clearly less
prone to accept a proton from the nucleophilic water molecule .
to
test this reaction path , we have obtained in principle the protonated
form of the first intermediate , hialt ( see
figure s8 in the supporting information ) . here
h2 , and the remaining oh from the water
molecule forms a bond with ca .
the relative energy of this
intermediate is very high , 58.4 kcal / mol for ttc ,
and for ttt we could not even locate this critical
point as calculations converged back to the reactant state . in an
alternative pathway ,
the reaction could start with the addition of
water directly to the central ca
cb double - bond ,
with oh forming a bond with ca , and
h coupling to cb . however , this reaction path
is also much higher than any critical point along the reaction observed
for mc , as the corresponding ts has a relative energy of 49.9 and
48.5 kcal / mol for the ttc and ttt conformers , respectively .
the very high energy critical points observed
for the hydrolysis paths of mch are clearly a consequence
of either the protonation per se , or the fact that
a direct addition of water to the central ca
the similarity of the results
obtained for ttc and ttt demonstrates
that a change in the initial mch conformation for this
reaction would not alter the energetics significantly .
furthermore ,
considering the structure of the hydrolysis products hp , the initial
addition of water can not take place in any alternative way , which
is why we conclude that mch is not susceptible to hydrolysis .
the nomenclature of the different conformers in
the reactant state mc is based on the cis or trans position of the central three bonds , here
shown for the lowest energy conformer , ttc .
we have investigated
the behavior of six spiropyran derivatives
in aqueous solution between ph 0 and 10 .
the following conclusions
can be drawn : ( i ) the substitution pattern influences
substantially the rates of the thermal isomerization processes as
well as the pka - values for the protonated
forms of sp and mc ( sph and mch ) .
interestingly ,
the pka of sph is decreased
by as much as 2 units by the attachment of positively charged
amino groups to the indoline nitrogen via alkyl linkers .
this allows
for photoinduced isomerizations between the sp and the mc forms over
a wider ph range .
( ii ) the apparent rate of hydrolysis of the mc isomer varies significantly with the
substitution pattern .
this , however , is a result of the differences
in the thermal equilibrium positions [ mc]/[sp ] , whereas the intrinsic
rate constant of hydrolysis is virtually the same for all derivatives .
( iii ) the rate constant of hydrolysis does not vary
significantly between ph 5 and 9 , clearly suggesting that water is
the nucleophile in this ph range .
( iv ) the nonprotonated
mc isomer is the only form that is susceptible to hydrolysis .
this
is due to the key role of the phenolate oxygen , acting as a base by
accepting a proton from the nucleophilic water , and later transferring
it to the farther carbon , cb . as a consequence
, the hydrolytic
degradation is halted at ph values where mch is the dominating
open form . | six water - soluble spiropyran derivatives
have been characterized
with respect to the thermal and photoinduced reactions over a broad
ph - interval .
a comprehensive kinetic model was formulated including
the spiro- and the merocyanine isomers , the respective protonated
forms , and the hydrolysis products .
the experimental studies on the
hydrolysis reaction mechanism were supplemented by calculations using
quantum mechanical ( qm ) models employing density functional theory .
the results show that ( 1 ) the substitution pattern dramatically influences
the pka - values of the protonated forms
as well as the rates of the thermal isomerization reactions , ( 2 ) water
is the nucleophile in the hydrolysis reaction around neutral ph , ( 3 )
the phenolate oxygen of the merocyanine form plays a key role in the
hydrolysis reaction .
hence , the nonprotonated merocyanine isomer is
susceptible to hydrolysis , whereas the corresponding protonated form
is stable toward hydrolytic degradation . |
minimally invasive surgery total knee arthroplasty ( mis - tka ) requires downsizing or modification of surgical equipment due to the small field of view ; medial / lateral or proximal / distal movement of a retractor to secure an adequate field of view ; extension / flexion or medial / lateral rotation of the knee joint during surgery ; and , above all , continuous development of surgical techniques and cooperation of the members of a surgical team1,2,3,4,5 ) .
in addition , the use of an implant designed specifically for mis can improve the efficiency of the surgery . the mini - keel modular tibial implant ( nexgen mis tibial component ; zimmer inc . , warsaw , in , usa ) is one of those inventions that can be inserted into the knee in flexed position without anterior dislocation of the knee joint due to the presence of a short keel in the tibial component ( fig . 1)6 ) . the purpose of this study was to evaluate the efficacy and longevity of the mini - keel modular tibial implant in mis - tka based on a retrospective review of clinical and radiological findings .
a total of 375 tkas were performed by the same surgeon at our institution between november 2005 and october 2006 . of those ,
361 tkas were performed via minimally invasive approach in 254 patients , and surgical outcomes and intraoperative complications were investigated among these patients .
clinical and radiological assessments were performed in patients who were available for more than 5-year follow - up . in all cases ,
the nexgen legacy posterior stabilized flex fixed bearing ( lps flex fixed , zimmer inc . ) and the nexgen mis tibial component were used .
the mean age of the patients was 68.8 + 5.6 years ( range , 53 to 80 years ) .
the mean body mass index was 273.7 kg / m ( range , 20.6 to 36.8 kg / m ) .
the indications for surgery were degenerative arthritis in 165 cases , rheumatoid arthritis in 2 cases , and osteonecrosis in 1 case .
preoperatively , the mean range of motion ( rom ) was 125.217.7 ( range , 70 to 145 ) , the mean knee score was 65.07.6 points ( range , 22 to 82 points ) , and the mean femorotibial angle was 4.05.6 varus ( range , 21 varus to 2 valgus ) .
clinical and radiological assessments were conducted at the last follow - up in 168 cases that were available for more than 5-year follow - up on an outpatient basis .
one hundred and forty- one cases that were available for a phone interview only in january 2013 were excluded from the clinical evaluation and so were the 79 cases ( due to death in 23 , nursing home admission in 10 , intertrochanteric fracture in 4 , distal femur fracture in 3 , transtibial amputation in 1 , infection - related revision in 1 , immigration to a foreign country in 1 , and loss of contact in 36 cases ) .
a curved skin incision was made from 5 mm above the medial patella to the superior aspect of the medial tibial tuberosity . in cases
where severe skin retraction was observed or there was difficulty with the operation or implant insertion , the skin incision was extended gradually proximally or distally to avoid excessive tension on the skin .
then , the joint was excised using the mini - midvastus approach7,8 ) : a 1.5 cm proximal incision was started superomedial to the patella in parallel to the vastus medialis muscle fibers and extended along the medial patella to 3 cm distal to the knee joint surface .
the patella was resurfaced in all cases . a 6 valgus intramedullary alignment rod attached to a distal cutting guide
was inserted into the center of the knee joint where the anatomical axis of the femur passes though . with the distal cutting guide pin fixed on the medial aspect of the medial femoral condyle ,
a proximal tibial cut was performed using an extramedullary alignment rod as in conventional tka . using the cutting guide ,
the osteotomy was initiated on the anteromedial aspect of the tibia and extended to involve approximately more than 80% of the proximal tibia except for some posterolateral and lateral areas . due to the limited field of view
the rotational alignment of the femur was determined in reference to the posterior condylar axis . at the same time , the appearance of the ' grand - piano sign'9 ) on the anterior resected surface of the femur was confirmed before resection . with the tibial component
temporarily press - fitted , a 45 mm drop - down stem extension was additionally inserted to increase the contact surface between the tibial component and the tibia and fixation strength .
for the 3 postoperative days , a deep vein thrombosis ( dvt ) foot pump was used to prevent dvt without administration of thrombolytic agents .
within 2 postoperative days , ambulation was permitted depending on the patient 's condition . on the postoperative clinical evaluation , the hospital for special surgery ( hss ) score , knee society score ( kss)10 ) , and rom
were assessed at the last follow - up in the 168 cases that were available for more than 5-year follow - up . on the radiological evaluation , the femorotibial angle , tibial component alignment angle , and tibial component posterior inclination
were assessed on the standing anteroposterior and lateral views taken at the last follow - up according to the knee society total knee arthroplasty roentgenogrphic evaluation11 ) .
in addition , implant location and fixation status were assessed . to assess the implant fixation status ,
the bone - cement or cement - implant contact area was divided into 7 zones on the lateral view for the femoral component , whereas into 7 zones on the anteroposterior view and 3 zones on the lateral view for the tibial component .
the width of radiolucent lines on 5 different zones on the skyline view was measured to assess the stability of the patellar component .
presence of a 2-mm - wide radiolucent line , implant subsidence , or change in the alignment was considered as a sign of radiological loosening .
. 12.0 ( spss inc . , chicago , il , usa ) was used for statistical analysis .
preoperative and postoperative clinical findings were compared using a t - test with statistical significance set at p<0.05 .
a total of 375 tkas were performed by the same surgeon at our institution between november 2005 and october 2006 . of those ,
361 tkas were performed via minimally invasive approach in 254 patients , and surgical outcomes and intraoperative complications were investigated among these patients .
clinical and radiological assessments were performed in patients who were available for more than 5-year follow - up . in all cases ,
the nexgen legacy posterior stabilized flex fixed bearing ( lps flex fixed , zimmer inc . ) and the nexgen mis tibial component were used .
the mean age of the patients was 68.8 + 5.6 years ( range , 53 to 80 years ) .
the mean body mass index was 273.7 kg / m ( range , 20.6 to 36.8 kg / m ) .
the indications for surgery were degenerative arthritis in 165 cases , rheumatoid arthritis in 2 cases , and osteonecrosis in 1 case .
preoperatively , the mean range of motion ( rom ) was 125.217.7 ( range , 70 to 145 ) , the mean knee score was 65.07.6 points ( range , 22 to 82 points ) , and the mean femorotibial angle was 4.05.6 varus ( range , 21 varus to 2 valgus ) .
clinical and radiological assessments were conducted at the last follow - up in 168 cases that were available for more than 5-year follow - up on an outpatient basis .
one hundred and forty- one cases that were available for a phone interview only in january 2013 were excluded from the clinical evaluation and so were the 79 cases ( due to death in 23 , nursing home admission in 10 , intertrochanteric fracture in 4 , distal femur fracture in 3 , transtibial amputation in 1 , infection - related revision in 1 , immigration to a foreign country in 1 , and loss of contact in 36 cases ) .
a curved skin incision was made from 5 mm above the medial patella to the superior aspect of the medial tibial tuberosity . in cases
where severe skin retraction was observed or there was difficulty with the operation or implant insertion , the skin incision was extended gradually proximally or distally to avoid excessive tension on the skin .
then , the joint was excised using the mini - midvastus approach7,8 ) : a 1.5 cm proximal incision was started superomedial to the patella in parallel to the vastus medialis muscle fibers and extended along the medial patella to 3 cm distal to the knee joint surface .
the patella was resurfaced in all cases . a 6 valgus intramedullary alignment rod attached to a distal cutting guide
was inserted into the center of the knee joint where the anatomical axis of the femur passes though . with the distal cutting guide pin fixed on the medial aspect of the medial femoral condyle ,
a proximal tibial cut was performed using an extramedullary alignment rod as in conventional tka . using the cutting guide ,
the osteotomy was initiated on the anteromedial aspect of the tibia and extended to involve approximately more than 80% of the proximal tibia except for some posterolateral and lateral areas . due to the limited field of view
the rotational alignment of the femur was determined in reference to the posterior condylar axis . at the same time , the appearance of the ' grand - piano sign'9 ) on the anterior resected surface of the femur was confirmed before resection . with the tibial component
temporarily press - fitted , a 45 mm drop - down stem extension was additionally inserted to increase the contact surface between the tibial component and the tibia and fixation strength .
for the 3 postoperative days , a deep vein thrombosis ( dvt ) foot pump was used to prevent dvt without administration of thrombolytic agents .
on the postoperative clinical evaluation , the hospital for special surgery ( hss ) score , knee society score ( kss)10 ) , and rom were assessed at the last follow - up in the 168 cases that were available for more than 5-year follow - up . on the radiological evaluation , the femorotibial angle ,
tibial component alignment angle , and tibial component posterior inclination were assessed on the standing anteroposterior and lateral views taken at the last follow - up according to the knee society total knee arthroplasty roentgenogrphic evaluation11 ) .
in addition , implant location and fixation status were assessed . to assess the implant fixation status ,
the bone - cement or cement - implant contact area was divided into 7 zones on the lateral view for the femoral component , whereas into 7 zones on the anteroposterior view and 3 zones on the lateral view for the tibial component .
the width of radiolucent lines on 5 different zones on the skyline view was measured to assess the stability of the patellar component .
presence of a 2-mm - wide radiolucent line , implant subsidence , or change in the alignment was considered as a sign of radiological loosening .
spss ver . 12.0 ( spss inc . , chicago , il , usa ) was used for statistical analysis .
preoperative and postoperative clinical findings were compared using a t - test with statistical significance set at p<0.05 .
the mean follow - up period was 6 years and 1 month ( minimum , 5 years ; maximum , 7 years and 7 months ) .
the mean postoperative femorotibial angle was 5.21.7 valgus ( range , 2.6 to 8.1 ) and the mean tibial component alignment angle was 90.21.6 varus ( range , 86.5 to 93.4 ) .
the mean tibial component posterior inclination was 4.82.1 ( range , 1.9 to 8.1 ) .
the femorotibial alignment angle was 63 valgus in 340 of the 361 cases ( 94.0% ) and the tibial component alignment angle was 03 varus in 347 cases ( 96.1% ) ( table 1 ) .
the mean rom was increased from 125.217.7 ( range , 70 to 145 ) preoperatively to 134.312.4 ( range , 85 to 145 ) postoperatively .
the mean postoperative kss was 94.55.9 points ( range , 68 to 100 points ) , function score was 84.815.6 points ( range , 54 to 100 points ) , and hss was 92.77.0 points ( range , 62 to 100 points ) , all of which were significantly improved after surgery ( table 2 ) .
revision was not necessary in all cases based on the last follow - up radiological assessment which showed no evidence of femoral / tibial component alignment change , subsidence , or loosening .
radiolucency was observed in more than one zone in the bone - implant interface in 22 cases ( 13.1% ) at the last follow - up : in the femur and tibia both in 4 cases , in the femur only in 10 cases , in the tibia only in 7 cases , and in the patella only in 1 case .
the components demonstrated stable fixation without signs of alignment changes or loosening in all cases .
the radiolucency was observed in 1 zone in 15 cases , in 2 zones in 4 cases , and in more than 3 zones in 3 cases . in the femur , it was located in zone 1 in 8 cases , in zone 2 in 1 case , and in zone 4 in 8 cases . in the tibia , it was observed in zone 1 in 9 cases , in zone 2 in 3 cases , and in zones 4,5 , and 7 in 1 case each on the anteroposterior view whereas in zone 3 in 2 cases on the lateral view . in the patella , it was found in zone 1 in 1 case ( table 3 ) .
the mean survival rate per kaplan - meier analysis was 99.4% at 6.1 years ( fig .
revision was required due to component loosening in one of the 168 cases that were followed for more than 5 years .
the mean follow - up period was 6 years and 1 month ( minimum , 5 years ; maximum , 7 years and 7 months ) .
the mean postoperative femorotibial angle was 5.21.7 valgus ( range , 2.6 to 8.1 ) and the mean tibial component alignment angle was 90.21.6 varus ( range , 86.5 to 93.4 ) .
the mean tibial component posterior inclination was 4.82.1 ( range , 1.9 to 8.1 ) .
the femorotibial alignment angle was 63 valgus in 340 of the 361 cases ( 94.0% ) and the tibial component alignment angle was 03 varus in 347 cases ( 96.1% ) ( table 1 ) .
the mean rom was increased from 125.217.7 ( range , 70 to 145 ) preoperatively to 134.312.4 ( range , 85 to 145 ) postoperatively .
the mean postoperative kss was 94.55.9 points ( range , 68 to 100 points ) , function score was 84.815.6 points ( range , 54 to 100 points ) , and hss was 92.77.0 points ( range , 62 to 100 points ) , all of which were significantly improved after surgery ( table 2 ) .
revision was not necessary in all cases based on the last follow - up radiological assessment which showed no evidence of femoral / tibial component alignment change , subsidence , or loosening .
radiolucency was observed in more than one zone in the bone - implant interface in 22 cases ( 13.1% ) at the last follow - up : in the femur and tibia both in 4 cases , in the femur only in 10 cases , in the tibia only in 7 cases , and in the patella only in 1 case .
the components demonstrated stable fixation without signs of alignment changes or loosening in all cases .
the radiolucency was observed in 1 zone in 15 cases , in 2 zones in 4 cases , and in more than 3 zones in 3 cases . in the femur , it was located in zone 1 in 8 cases , in zone 2 in 1 case , and in zone 4 in 8 cases . in the tibia , it was observed in zone 1 in 9 cases , in zone 2 in 3 cases , and in zones 4,5 , and 7 in 1 case each on the anteroposterior view whereas in zone 3 in 2 cases on the lateral view . in the patella , it was found in zone 1 in 1 case ( table 3 ) .
the mean survival rate per kaplan - meier analysis was 99.4% at 6.1 years ( fig .
revision was required due to component loosening in one of the 168 cases that were followed for more than 5 years .
determining whether mis is an appropriate treatment option in tka requires assessments on its conformity to standard operating principles , such as flexion / extension gap balancing , restoration of proper alignment , prevention of intraoperative complications , and achievement of expected surgical outcome1,2,7,12,13,14,15 ) . in the current study ,
the mis - tka demonstrated relatively high accuracy : the tibial component alignment angle was 03 varus in 347 of the 361 cases ( 96.1% ) and the femorotibial angle was 63 valgus in 340 cases ( 94.0% ) .
this can be attributed to the proper placement of the cutting alignment guide during surgery in spite of the limited field of view , considering that femoral and tibial alignments are dictated by the intramedullary / extramedullary alignment guide . during surgery
, we expected the side cutting technique for distal femoral cut would result in minimal soft tissue damage and verified firm attachment of the distal cutting guide to the 6 valgus intramedullary alignment rod for precise osteotomy in the medial condyle of the distal femur . for lateral femoral resection , this intramedullary alignment rod
should be removed : thus , the remaining distal cutting guide on the medial aspect of the medial femoral condyle can be displaced by soft tissue during the procedure . in addition
, the osteotomy should be carried out in the absence of proper field of view , rendering it difficult to conduct precise resection . to overcome this obstacle , we removed the distal cutting guide as well and used a free hand technique for lateral femoral condyle resection by referring to the resected surface of the medial femoral condyle . with experience
, mis - tka can be performed through a small incision without applying excessive tension on the surrounding soft tissue : however , implant insertion can still be challenging if the field of view is extremely limited1,3,4,14 ) . in order to insert conventional tibial components that have long stems
, the tibial resection surface should be sufficiently anteriorly dislocated relative to the femoral resection surface with the knee in flexion
. this may be not feasible if the incision is small , result in complications caused by excessive tension on the adjacent tissue , or require additional soft tissue resection .
the modular tibial implant ( nexgen mis precoat stemmed tibial plate & drop - down stem extensions ) was designed to overcome these disadvantages by allowing implant insertion in knee flexion without anterior dislocation of the tibia through a small field of view . the modular tibial implant is made of titanium alloy and composed of a mini - keel tibial plate and a 45 mm- or 75 mm - long modular stem ( drop - down stem extension ) .
the short keel length ( range , 17 to 19 mm ) in the tibial plate facilitates insertion into a flexed knee without anterior dislocation of the tibia against the femur , thus preventing tension on the surrounding tissue and additional soft tissue resection .
however , care should be taken during insertion because the keel should be passed through a narrow small space in the flexed knee , and determining the exact insertion site can be challenging because the keel punch in the resected surface of the tibia is not easy to identify due to cement .
therefore , we applied sufficient traction with the knee in flexed position during mini - keel plate insertion and used a custom made holder to securely hold and precisely insert the implant through a narrow space .
although the length of the keel of the mini - keel tibial component is short compared to that of other tibial components , it provides 5.20% wider contact surface , thus not compromising stability of the knee .
however , in an attempt to obtain further stability by increasing the interface between the implant and the tibia , we additionally used a 45 mm drop - down stem extension in all knees .
benazzo and rossi6 ) first reported on the results of mis - tka using a modular tibial implant : the 5-year survival rate was 97.9% in 200 knees during the 3-year follow - up in the prospective study .
bonutti et al.2 ) demonstrated favorable clinical and radiological results : the 9-year survival rate was 97.1% in 90 knees . in the current study ,
the survival rate was as high as 99.4% at 6.1 years after mis - tka using a mini - keel tibial implant , which can be attributed to appropriate realignment of the tibial component , proper selection for tibial fixation site , and the use of a drop - down stem extension for improved stability .
seo et al.5 ) documented that surgical site healing was delayed and the incidence of infection was high after mis - tka that was performed under limited visualization of the operative field compared to that after conventional tka due to severe skin traction and prolonged surgical time .
however , there was no case of infection except for 1 case that required revision due to infection at 6 years and 6 months after surgery .
the infection rate in our patients was significantly low compared to that in previous studies , which we believe is attributable to careful application of traction to skin and the relatively short surgical time ( 87.512.4 min ) .
most publications in the literature are reports on the short - term results of mis - tka using the conventional implants1,4,9,13,15,16,17 ) .
thus , the significance of this study can be found in the fact that we investigated more than 5-year mid - term follow - up results of mis - tka using a tibial component designed specifically for mis in a relatively large study population .
the limitations of this study include that the study design was retrospective and many of the 316 cases that underwent mis - tka were not included for analysis due to unavailability for outpatient clinic evaluation .
in addition , all the operations were performed by the same surgeon experienced in mis - tka .
although the procedure requires a long learning curve to achieve accuracy and reduce operation time1,8 ) , we think that long - term studies that involve multiple institutions and various surgeons should be conducted in the near future .
the more than 5-year mid - term follow - up of mis - tka using a mini - keel modular tibial implant in 168 cases showed high implant survivorship and satisfactory clinical and radiological results . | purposeto evaluate the minimum 5-year mid - term clinical and radiological results of minimally invasive surgery total knee arthroplasty ( mis - tka ) using a mini - keel modular tibia component.materials and methodswe retrospectively evaluated 254 patients ( 361 cases ) who underwent mis - tka between 2005 and 2006 .
the latest clinical and radiological assessments were done in 168 cases that had been followed on an outpatient basis for more than 5 postoperative years .
clinical results were assessed using the hospital for special surgery ( hss ) score and knee society score .
radiological evaluation included measurements of knee alignment.resultsthe average postoperative knee range of motion and hss score were 134.312.4 and 92.77.0 , respectively .
the average postoperative femorotibial angle and tibial component alignment angle were 5.21.7 valgus and 90.21.6 , respectively .
the average tibial component posterior inclination was 4.82.1. the percentage of cases with tibial component alignment angle of 903 was 96.1% , and that with the femorotibial angle of 63 valgus was 94.0% .
radiolucent lines were observed in 20 cases ( 12.0% ) : around the femur , tibia , and patella in 14 cases , 10 cases , and 1 case , respectively .
however , they were less than 2 mm and non - progressive in all cases .
the survival rate was 99.4% and there was no implant - related revision.conclusionsmis-tka using a mini - keel modular tibial plate showed satisfactory results , a high survival rate , and excellent clinical and radiological results in the mid - term follow - up . |
motor dysfunction due to neural disorders is responsible for several complications in patients recovering from stroke . in particular
impairments resulting in gait disorder have been reported previously , such as muscle weakness , spasticity , and , most importantly , poor motor coordination .
previous studies have investigated the problem of motor coordination using cocontraction between agonist and antagonist muscles in patients after stroke [ 57 ] . however , the effects of cocontraction on gait were not consistent in these studies .
one study suggested that excessive cocontraction during gait may adversely affect the energy cost during gait , whereas another study reported that cocontraction is needed as an adaptive behavior for retaining stability during gait .
this inconsistency in evidence reflects the limitations of using cocontraction as an indicator of motor coordination during gait .
therefore , a more comprehensive and specific indicator is needed for motor coordination in patients after stroke . in general
, the brain needs to coordinate the degrees of freedom in the musculoskeletal system during movement , and muscle synergy is hypothesized to manage the problem with degrees of freedom . based on this hypothesis ,
the central nervous system controls muscle synergy , which comprehensively coordinates the activation of several muscles during movement .
recent studies have demonstrated that the number and structure of muscle synergies can be directly identified using nonnegative matrix factorization ( nnmf ) with surface electromyography ( emg ) during gait and reaching tasks [ 1012 ] . the physiological validity and robustness of this method
have been demonstrated in previous studies [ 13 , 14 ] . using this method ,
it was reported that the number of synergies did not change in patients with spinal cord injury ( sci ) .
however , the evidence is conflicting in poststroke patients , with one study demonstrating a similar number of synergies in poststroke patients and healthy adults and another reporting a decreased number of synergies in patients after stroke .
the study that reported no changes in the number of synergies recruited patients after subacute stroke , whereas the study demonstrating a reduced number of synergies recruited patients after chronic stroke .
furthermore , one previous study investigated the change in muscle synergy in patients after chronic stroke .
the study demonstrated that muscle synergies were fine - tuned and that the number of synergies was increased in some patients with improved motor function .
however , the change in muscle synergies , including the number and structure of synergies , in patients after subacute stroke has not been clarified . of clinical importance is another previous study that demonstrated that muscle synergy calculated by nnmf was strongly associated with a dynamic response during movement . for stroke patients , abnormal gait patterns
for example , abnormal gait kinematics were mostly represented at the knee joint or ankle joint , whereas the change in gait kinetics relating to gait function was shown at the ankle joint .
however , the longitudinal relationship between muscle synergy and gait dynamics in stroke patients is unknown .
another study reported that the merging and fractionation of muscle synergies could explain the changes in the number of synergies in patients after stroke .
merging was related to impairment of the upper limbs , and fractionation was related to the duration after stroke .
thus , it is considered that merging and fractionation could be used as indicators of motor coordination in patients after stroke .
however , the mechanism of how these changes occurred and whether they are related to the recovery of motor function remain unclear .
we conducted two consecutive measurements and clarified the changes in the number and structure of muscle synergies in patients after subacute stroke and investigated the relationship between the change in muscle synergy and change in motor function or gait dynamics during the recovery process .
patients with the following inclusion criteria were recruited : ( 1 ) a single stroke within 6 months prior to the study ; ( 2 ) ability to walk independently using an ankle - foot orthosis or t - cane ; ( 3 ) no gait symptoms from parkinson 's or ataxia ; ( 4 ) no pain during gait due to orthopedic disease ; ( 5 ) no limitation of activity due to heart disease ; and ( 6 ) no difficulty in understanding the experimental tasks due to cognitive problems .
thirteen patients who had experienced subacute stroke met the inclusion criteria and participated in this study ( mean time elapsed after stroke : 66.8 24.2 days ) .
this study was approved by the ethics committee of kyoto university graduate school , faculty of medicine , and yufuin kosei nenkin hospital , and we obtained informed consent from all patients .
two measurements ( first and second measurements ) were performed at 1-month intervals . between the first and second measurements , all patients participated in the inpatient rehabilitation program , which included gait training , balance training , and task - specific training for activities of daily living ( adl ) for 60 minutes per day , five times per week . during each recording ,
two gait trials were performed by asking patients to walk a 10 m long walkway at a chosen speed with or without a cane .
muscle activity was recorded simultaneously with surface emg ( semg ) using a trigno wireless system ( delsys co. , boston , usa ; sampling rate : 4000 hz ) , which also recorded the data from a 3d accelerometer ( acc ) .
the semg activity was recorded from the tibialis anterior ( ta ) , lateral gastrocnemius ( gs ) , soleus ( sl ) , gluteus medius ( gm ) , rectus femoris ( rf ) , vastus medialis ( vm ) , biceps femoris ( bf ) , and semitendinosus ( st ) muscles of the affected side , and another sensor was placed on the heel of the measured limb to record the acc data .
the corrected semg data were bandpass - filtered ( 20250 hz ) , rectified , and then low - pass filtered ( 10 hz ) .
furthermore , the amplitude was normalized to the peak activity recorded during five gait cycles .
a factor analysis was performed with the normalized data ( nemg ) . for each subject
, the nemg data were separated into patterns of synergies and muscle weightings using an nnmf algorithm .
the nemg data m(t ) are represented by the following equation:(1)mt=i1ncitwi.this algorithm could reveal synergies in the following two matrices : ci(t ) , which denotes the activation pattern of each synergy during five gait cycles ( n t matrix ; n = number of synergies , t = time point ) , and wi , which represents the weightings of the muscles involved in each synergy ( m n matrix ; m = eight muscles of the paretic leg ) .
the nemg data were reconstructed by iteratively updating the values of these matrices until they converged .
the nnmf analyses were performed with the output restricted to one , two , three , four , or five synergies , with no a priori assumptions about the adequate number of synergies .
the reconstructed emg ( remg ) was calculated by performing matrix multiplication , with both matrices indicating the activation pattern and weightings of synergies ; the sum of squared errors ( nemg - remg ) was then calculated .
the variability accounted for ( vaf ) , which was the ratio of the sum of the squared error to the sum of the squared nemg , was calculated to determine whether the minimum number of synergies corresponded with adequate remg . because the threshold of vaf could potentially change the number of synergies , we used the threshold from a previous study .
we determined that additional synergies were not required if vaf including all muscles was 90% .
the change in structure of muscle synergy was investigated using merging and fractionation indices calculated with a linear combination , as reported in a previous study .
the merging index was defined as the ratio of the frequency of merging of the synergy to the total number of synergies in the first measurement , whereas the fractionation index was defined as the ratio of frequency of fractionation of the synergy to the total number of synergies in the first measurement ( figure 1 ) .
the timed up and go test ( tug ) and the short - form berg balance scale ( sfbbs ) were used to assess the function of dynamic or static balance for each patient .
furthermore , the muscle strength ( nm ) of five muscles ( hip flexor , knee extensor , knee flexor , ankle dorsiflexor , and ankle plantar flexor ) was measured using a hand - held dynamometer ( -tas f-1 ; anima corp . ,
furthermore , the change in the parameters of motor function ( speed , tug , sfbbs , bi , and strength ) was represented by the ratio of change among trials involving the value of the first measurement .
a follow - up gait measurement was also performed in the same motion analysis laboratory .
the laboratory had a 3d motion analysis system ( t-10 ; vicon motion system ltd . ,
oxford , uk ) with eight cameras and a sampling frequency of 100 hz .
reflective markers were attached to the body according to the vicon plug - in - gait ( pig ) marker placement protocol ( full body ) .
data were processed using pig software , which uses a woltring filter , and joint kinematics were generated using inverse dynamics analysis within nexus version 1.7 software ( vicon motion system ltd . ) .
the data recorded by 3d motion analysis were time - normalized to 100% gait cycle ( gc ) .
the parameters of gait kinematics at the hip , knee , and ankle joints were detected as the peak of the joint angle during the gait cycle , as shown in table 2 .
furthermore , the changes in gait kinematics between measurements were calculated as the difference or ratio of change in peak or angle range , respectively .
first , interclass correlation coefficients ( icc(1,1 ) ) were calculated between the two trials of the first measurements to investigate the test - retest reliability of the number of synergies indicated by nnmf .
second , the paired t - test and wilcoxon signed - rank test were used to examine the differences in clinical parameters , gait kinematics , and the number of synergies between the two measurements .
furthermore , the relationship between the merging index or fractionation index and the change in clinical parameters or gait kinematics was investigated using multiple linear regression with stepwise procedures and using the change in clinical parameters and gait kinematics at three joints as explanatory variables and the merging and fractionation indices as target variables .
table 3 shows the changes in the number of synergies , merging and fractionation indices , and the motor function at the first measurement . regarding the number of synergies , the results showed high test - retest reliability ( icc = 0.81 , almost perfect ) .
furthermore , the results showed that gait speed and muscle strength had significantly improved ( p < 0.01 and p < 0.05 , resp . ) . other parameters including bi , tug , and bbs also significantly improved .
however , no consistent changes in the number of synergies between the first and second measurements were found ( p = 0.73 ) .
the peaks of flexion at the hip ( hip f1 ) and knee ( knee f1 , f2 ) tended to increase after a month ; however , the other peak angles at the three joints did not show a consistent change between two measurements .
furthermore , the ranges of hip and knee joints had increased since the first measurement ; however , the ankle joint range did not show a consistent change .
merging of synergy was observed in eight patients ( 61.5% ) after stroke , whereas fractionation was found in 10 patients ( 76.9% ) after stroke .
the merging index was associated with the change of muscle strength and range of the ankle joint with a significant coefficient of determination ( table 4 ) .
changes in gait speed , sfbbs , and tug were not significantly associated with the merging or fractionation indices .
our present study clarified the longitudinal change in muscle synergy calculated using nnmf for patients after subacute stroke .
the high test - retest reliability was confirmed by the number of synergies calculated by nnmf . using this method ,
a consistent change in the number of synergies was not found at monthly measurements , even though patients had significantly improved gait speed .
however , merging of synergy was found in 61.5% of patients and fractionation of synergy was found in 76.9% of patients in this study .
furthermore , the extent of merging and fractionation depended on motor function and gait dynamics .
a previous study showed a change in timing and composition of muscle synergy in chronic stroke patients .
the results showed that the fine - tuning of muscle synergy and the increase in the number of synergies were associated with improvement in motor function .
however , in this study , a consistent increase or decrease of the number of synergies was not found in subacute stroke patients with improved motor function .
the results reflected that the neural networks relating to the number of synergies in subacute stroke patients did not change homogeneously . in a previous cross - sectional study ,
severe stroke patients showed higher merging index and lower motor function as estimated by the fugl - meyer scale .
as a longitudinal change in present study , the present results suggest that higher merging index was associated with poor improvement of outcome , such as muscle strength and gait kinematics . specifically , the patients with merging of synergy had poor improvement in muscle strength and restriction of ankle joint range at monthly measurements ( figure 2 ) .
the merging of synergy indicated by nnmf is thought to represent synchronization of the neural network .
therefore , it is considered that the merging of synergy may represent the compensative neural change to achieve a dynamic response after improvement of gait .
the fractionation index was associated with duration after stroke in a previous study . in the present study , an association between the fractionation and duration after stroke was not found because the patients were inpatients .
this suggested that the fractionation of synergy was influenced by the complexity of several movements in adl during the recovery process .
first , our sample size was small for the convenience of sampling , resulting in a small range of variability of motor function in the subjects .
future studies should include patients with more severe symptoms to allow a better understanding of the characteristics of synergy behavior .
other limitations were the small number of gait cycles assessed and use of a cane by some patients
however , a previous study also used a small number of gait cycles ( 10 gait cycles ) for patients with sci who were unable to walk long distances .
thus , a larger number of gait cycles and gait measurements without a cane are required to accurately investigate the synergy during gait .
furthermore our results showed the neural change during the short period , in which the patients significantly improved motor function .
therefore , future studies should also measure the muscle synergy and motor function at more time points to clarify the long - term changes in muscle synergy in patients after stroke .
the results of this study showed that the number of synergies did not consistently change with the recovery of motor function in subacute stroke patients .
the merging of synergy was especially related to the unchanged muscle strength and abnormal gait pattern .
the results of the present study suggest that nnmf can be used to clarify the characteristics of motor coordination in stroke patients and that the merging of synergies is thought to be an important marker of poor motor coordination . | loss of motor coordination is one of the main problems for patients after stroke .
muscle synergy is widely accepted as an indicator of motor coordination .
recently , the characteristics of muscle synergy were quantitatively evaluated using nonnegative matrix factorization ( nnmf ) with surface electromyography .
previous studies have identified that the number and structure of synergies were associated with motor function in patients after stroke . however , most of these studies had a cross - sectional design , and the changes in muscle synergy during recovery process are not clear . in present study , two consecutive measurements were conducted for subacute patients after stroke and the change of number and structure of muscle synergies during gait were determined using nnmf .
results showed that functional change did not rely on number of synergies in patients after subacute stroke .
however , the extent of merging of the synergies was negatively associated with an increase in muscle strength and the range of angle at ankle joint .
our results suggest that the neural changes represented by nnmf were related to the longitudinal change of function and gait pattern and that the merging of synergy is an important marker in patients after subacute stroke . |
half of any population is constituted by women who experience different periods in their life each of which affect their health in a different way .
in addition , conditions such as pregnancy and breast - feeding , through the depletion of body reserves , will increase the aging - related complications such as osteoporosis as one of the most problematic issues of women in their aging period . on the other hand ,
the bone density of women is approximately 20 to 30% less than men , while bone resorption in women is twice then men , especially if they have had a long pregnancy and lactation period in their life .
it has been reported that for every 100 days lactation , 2% of women 's bone mass will decrease .
in addition , in a period of their life , women experience a stage called menopause when , through the decrease of estrogen levels , the rate of bone resorption increases extremely . through the development of health in the societies and the societies health promotion life expectancy
thus , women 's length of life has been increased despite their menopausal conditions , so that they spend about 30 years of their life in their postmenopausal period .
although menopause , that occurs between the ages of 44 and 55 , is a natural phenomenon , the lower levels of estrogen after the reduced function of ovarian causes various psychological and physical disorders that osteoporosis is one of the most problematic of these disorders , whose complications impose high costs on the society . while the reduction of bone density is inevitable after the age 35 , adequate calcium intake can significantly reduce its speed .
the daily needs of body to calcium are different in different age groups . in perimenopausal periods
calcium - rich foods include low - fat dairy products , dark green vegetables such as broccoli and spinach , sardines , salmon , nuts , beans , soya , and calcium drinks .
regarding the latest statistics about iranians food basket , the daily consumption of dairy is 139 g for every individual that is very low in comparison with the right amount of dairy consumptions as the optimal level of dairy consumption is considered to be about 225 to 240 g . according to the low per capita income of iranian families , dairy products and other calcium - rich foods
calcium deficiency will lead to osteoporosis that have been seen in about 2/5 million iranians . according to the results
, osteoporosis has led to 200 to 400 thousand fractures in iran that imposes more than four million dollars on the country each year . while , through changing the lifestyle and nutritional behavior of the people many of these problems can be prevented .
nutritional behaviors , like other health - related behaviors , are influenced by many factors that recognizing them can be helpful in predicting behaviors and development of health - promotion programs .
people 's perception of the threatening conditions is a psychological factor that can affect individuals performances .
understanding the psychological aspects of behavior can be a useful framework for the understanding of human behavior drivers in order to develop health programs , because the most effective training programs are based on the theoretical approaches and have been derived from the patterns of behavior changing . according to one of the behavior explaining theories ,
when people feel that their health is threatened by a certain behavior and a particular action can prevent this threat , they will be encouraged to do that action .
( 2008 ) found out in their study that behavioral functions of calcium intake has been increased in the menopausal women by the trainings based on the health beliefs model constructs .
although many studies have shown that the application of training to improve perceived threat can lead to the improvement of nutritional behaviors , it is important that the factors related to health behavior should be evaluated in the socio - cultural context of different societies .
therefore , before applying any training action , behavior explaining theories should be examined for the prediction of any behavior so that health promotion actions can be performed properly .
given the importance of using calcium - rich foods in preventing osteoporosis and also the need for a better understanding of the relevant factors , the aim of the present study is to identify the relationship between the perceived threat of osteoporosis and nutritional behaviors in taking calcium - rich foods .
this research is a descriptive - correlational study whose data has been collected by cross - sectional methods .
the study 's subjects consist of the women aged 44 to 55 ( premenopausal women ) that were selected from the women who have been referred to the health centers of semirom in 2013 .
inclusion criteria for the study include : not having nutritional therapeutic regimen that limits the use of calcium - rich foods , non - existence of known mental and psychological diseases , no history of cancer , the non - existence of bone - related diseases except arthritis osteoporosis .
data collection tool was a researcher - made questionnaire which consists of three parts : the first part was dedicated to the demographic - fertility characteristics ; the second part included the questions in relation with the consumption of calcium - rich foods in terms of daily consumption units ( each unit equals to a glass or 250ml milk ) ; and the third part contained the questions related to perceived susceptibility and the perceived severity of threat and was formulated in the five - point likert scale ( strongly agree , agree , no idea , somewhat disagree , disagree ) .
the questionnaire was completed by the study 's subjects and the scores were balanced based on the score 100 .
the questionnaire was designed through the study of scientific books , journals and articles and its validity was evaluated using the opinions of different experts .
the reliability of the questionnaire was determined at the end of the sampling and through specifying the cronbach'a alpha coefficient , and the score 0.78 was obtained for the questions .
the used statistical methods included frequency distribution , mean score , pearson correlation coefficient and multivariate regression analysis .
the patients who participated in this study received verbal and written explanation about the study process , privacy of data , their voluntary participation and right to withdraw from the study at any time .
the patients who participated in this study received verbal and written explanation about the study process , privacy of data , their voluntary participation and right to withdraw from the study at any time .
210 women aged between 44 and 55 , with the mean age of 48.3 3.8 participated in this study . in terms of educational level ,
29 percent of the women were illiterate , 40.5 percent of the women had primary education , 10 percent of them had high school education , 9 percent with diploma , and 11.4 percent of the women had a higher level of education . in terms of job , 70 percent were housewives , 13.8 percent were employees , 3.8 percent were workers , 9 percent were teachers , and 3.3 percent had other occupations . in terms of economic level , 20 percent of them had a poor economic situation , 74.3 percent had an average economic situation , and the rest ( 5.7% ) had a good economic situation . in terms of consumed units of calcium - rich foods , the maximum level has been 9.04 units per day and the minimum level has been 0.07 units .
the most common used calcium - rich foods have been dairy products with the maximum level of 9.3 units and the minimum level of 0.07 ; then , have been nuts with the maximum use of 1 unit and the minimum use of 0.00 ; and the least consumption belonged to broccoli with the maximum daily intake of 0.43 unit and the minimum intake of 0.00 [ table 1 ] .
the daily intakes of calcium and the mean perceived threat score of hbm for using calcium - rich foods and the complications caused by the inadequate intake of calcium - rich foods in the premenopausal women the results obtained from evaluating the relationship between the number of received calcium - rich foods units and the score of perceived susceptibility the perceived severity of threat and the complications caused by inadequate intake of calcium - rich foods showed that there has been a direct and significant relationship between them ( p < 0/001 ) : r = 0.651 ; r = 0.581 ; 0.634 ; 0.567 [ table 2 ] .
pearson correlation coefficient between the units of calcium - rich foods and the perceived threat score of using calcium - rich foods and the complications caused by the inadequate intake of calcium - rich foods in the premenopausal women according to the results , the perceived susceptibility and severity of threat have been directly and significantly related with the consumption of calcium - rich foods .
moreover , the relationship between the perceived susceptibility and severity of threat and the complications of inadequate intake of calcium has been significant .
regression line equation of calcium - rich foods with the scores of perceived susceptibility and perceived severity of threat caused by non - intake of calcium has been obtained as follows : y = 1.91 + 0.014x1 + 0.015x2 . in this equation
1.91 is the fixed coefficient of the equation . x1 and x2 also respectively refer to the perceived susceptibility and severity of taking calcium - rich foods . as it is obvious , although there is a close relationship between the variables of perceived susceptibility and severity with the rate of using calcium - rich foods , the greatest impact on the calcium - rich foods has been by x2 as the perceived severity of threat and then by x1 as the perceived susceptibility .
moreover , regression line equation of calcium - rich foods with the scores of perceived susceptibility and perceived severity of threat caused by the inadequate intake of calcium has been obtained as follows : y = 2.01 + 0.027z1 + 0.02z2 . in this equation , y refers to the number of times calcium - rich foods are used .
2.01 is the fixed coefficient of the equation . z1 and z2 also respectively refer to the perceived susceptibility and severity of threat caused by inadequate intake of calcium - rich foods .
as it can be seen , although there is a close relationship between the variables of perceived susceptibility and severity of threat caused by the inadequate intake of calcium with the rate of using calcium - rich foods , the greatest impact on the calcium - rich foods has been by z1 as the perceived susceptibility and then by z1 as the perceived severity of threat .
according to the results of the study , the intake of diary and calcium - rich foods is to a great extent close to the level recommended for this age that is three iu .
indeed , calcium - rich vegetables should be used more , but according to the specific food habits of the area and less access to these kinds of foods and also according to the consumption barriers , they have been used less than normal .
it seems that one of the main reasons for the relatively good consumption of calcium - rich foods is the access to the various kinds of dairy products in this area and also the affordable price of these products compared with the meat products .
this amount of dairy consumption is in line with other researches in other areas of iran . in the research conducted by torshizi ,
daily intake of calcium has been 821 - 900 mg ; in shojaeizadeh 's study , this amount has been 800 mg ; and in the study conducted by mossalanejad et al . , this amount has been less than 1200 mg for about 67.7% of women . in the study of swaim et al .
( 2008 ) , in the area of preventive behavior and in terms of calcium - rich foods , the results showed that 64% of menopausal women have used about 1000 - 1200 mg calcium that their results have been in line with the results of the current study .
the results also showed that , by increasing the scores of perceived susceptibility and perceived severity of threat , the consumption of calcium - rich foods has increased .
according to the theory of health belief model , the greater the perceived susceptibility and perceived severity of threat , the less will be the barriers of calcium consumption , and vulnerable people will try to correct inappropriate behaviors and change them into the appropriate healthy behaviors .
the results of this study are in agreement with the theories of health belief mode .
according to the results of this study , the structures of perceived susceptibility and perceived severity of threat in health belief model can be a good model for predicting the nutritional behavior of using calcium - rich foods and can be helpful in explaining factors that need to be emphasized more .
current study can be a useful guide in applying health belief model to prevent diseases , and understanding the vision and beliefs of people about the health - threatening illnesses , particularly the so - called silent and asymptomatic diseases that in turn can lead to the health programs for the promotion of healthy behaviors and leaving unhealthy behaviors .
from the findings of this study and other similar studies , it can be concluded that perceived threat can be a good predictor of behavior and , since half of the population of any society are women that according to their key role in the family and society need to be more considered in terms of nutritional behavior , therefore , using different training methods , especially the mentioned model , premenopausal women should be motivated to use more calcium - rich foods .
doing this , disabilities and mortalities caused by the non - consumption of calcium - rich foods can be prevented . | background : during women lives , frequently face the challenge of calcium reduction and absorption . decreased calcium absorption followed by a decrease in estrogen at perimenopausal ages , low average per capita calcium intake among women , wrong nutritional behavior , household income reductions and make them more susceptible to osteoporosis and related complications .
the aim of this study was to evaluate the relationship between the health belief model constructs and consuming calcium - rich foods in menopausal age women.materials and methods : this study was descriptive - correlation study .
the questionnaires were completed by 210 menopausal women who had referred to health centers .
the research data were analyzed using : frequency distribution , mean score , pearson correlation coefficients and multivariate regression .
significant level of p < 0/05 were considered.results:the mean and standard deviation of the scores for perceived susceptibility and severity of the threats of consumption and complications of inadequate intake were respectively : ( 62.1 and 38.9 , and 60.2 and 39.9 ) and ( 59.6 and 37.9 and 56.3 and 36.5 ) .
the relationship between the number of units of calcium intake with perceived susceptibility and severity calcium intake and complications caused by the inadequate intake of calcium were ( p < 0.001 , r = 0.581 , r = 0.651 ) and ( p < 0.001 , r = 0.634 , r = 0.567).conclusions : the obtained results indicate that perceived threat is the prognostic factor for the intake of calcium - rich foods and the increase of perceived threat in the health promotion programs may be associated with the increase in the consumption of calcium - rich foods in the women of premenopausal age . |
branch retinal vein occlusion ( brvo ) is one form of retinal vascular disease and is the second leading cause of loss of vision after diabetic retinopathy.1 according to klein population study ( beaver dam study ) , the incidence of brvo was approximately 1.8% and the prevalence of brvo was 0.3%1.1%.2,3 according to blue mountain eye study , the incidence of brvo was 1.6%.3,4 the most common symptom among brvo patients is decreased visual acuity and sudden loss of vision due to macular edema.1,2 since the branch vein occlusion study has been published , grid laser photocoagulation has been the standard treatment for macular edema in brvo patients .
the branch vein occlusion study reported that the mean increase in visual acuity was 1.33 lines in brvo patients treated with grid laser photocoagulation.5,6 limited visual outcome from grid laser photocoagulation therapy raised questions of alternative therapy to improve visual outcome in macular edema secondary to brvo.6 recent studies showed that there was an increased level of intraocular vegf in patients with retinal vein occlusion.6,7 vegf has been noted as an important factor correlated with increased retinal vascular permeability and macular edema in retinal vein occlusion.8,9 administration of the anti - vegf agent bevacizumab is expected to reduce macular edema and reinstitute visual outcome.9,10 studies to investigate the use of anti - vegf in retinal vein occlusion are rapidly growing .
the bravo and cruise studies showed good results in maintaining central retinal thickness and visual outcomes.6,11 however , all of the studies were done using multiple injections of anti - vegf , with the least mean of injections being two.911 repeated and long - term injections may increase the chance of ocular and systemic complications.12 multiple injections also add to the total cost of treatment.13 therefore , this study aimed at finding out whether a single injection of bevacizumab could improve the clinical outcome of macular edema secondary to brvo .
this was a clinical trial study of 19 patients diagnosed with macular edema secondary to brvo .
subjects were recruited after ethical clearance was obtained from the ethical committee of padjadjaran university .
inclusion criteria were patients ( less than 3 months of onset ) with diagnosis of macular edema secondary to brvo , age > 20 years , intraocular pressure less than 21 mmhg , adequate pupillary dilation , clear ocular media adequate for optical coherence tomography ( oct ) examination , and central macular thickness greater than 250 m .
exclusion criteria were history of other retinal diseases that could cause macular edema , history of intraocular surgery , retinal laser therapy , intravitreal triamcinolone injection or anti - vegf injection , and macular ischemia . after signing
the written informed consent , 19 subjects were chosen and divided into two groups based on block randomization .
group a ( n=9 ) was treated with laser photocoagulation therapy in combination with intravitreal bevacizumab injection , while group b ( n=10 ) was treated with laser photocoagulation therapy alone . for the laser therapy alone group ,
the laser surgery was performed when the hemorrhage had already been absorbed , maximum 3 months after the onset , with an average of 5 weeks .
macular laser photocoagulation therapy was performed using contact lens and double coupling frequency nd : yag ( neodymium - doped yttrium aluminium garnet ) laser .
grid laser photocoagulation was performed at 5003,000 m from central fovea with 50100 m spot size , time of exposure 0.050.1 seconds , moderate burn intensity , and the distance between spots is 12 spots .
subjects treated with laser photocoagulation therapy were reexamined 1 week , 1 month , and 3 months posttreatment . during 1-month and 3-month follow - up
the intravitreal bevacizumab injection of 1.25 mg or 0.05 ml was given to those subjects in the combination of therapy group in an operating room .
at 1 month follow - up after the injection , subjects were treated with laser photocoagulation therapy .
laser photocoagulation method was equal to the other group ; follow - ups were conducted after 1 week , 1 month , and 3 months of laser therapy to measure macular thickness via oct .
the main outcome measures were visual acuity , macular thickness , and the difference of macular thickness in both groups .
statistical analysis was performed by conducting student s t - test and mann whitney test on spss 15.0 ( spss inc . ,
chicago , il , usa ) to determine the difference in visual acuity and macular thickness on pretreatment and posttreatment on the two groups .
table 1 shows that there is no significant difference in age between the two groups ( p=0.72 ) .
there was no significant difference between the two groups with regard to sex ( p=1.00 ) .
characteristics of systemic conditions do not show a significant difference between the two groups ( p=0.53 ) .
these results show that the sample of this study was homogenous based on age , sex , and systemic conditions of both groups .
however , independent t - test was performed to examine the visual acuity after surgery and laser treatment because the data was normally distributed .
the outcomes are shown in tables 2 and 3 , with the result of t - test shown with confidence interval 95% . a significant difference in visual acuity between the two groups at 1-month and 3-month follow - up ( p=0.041 and p=0.037 , respectively ) can be observed .
macular thickness was measured using oct on the day of admission and 1 month after treatment . as can be seen from the values given in tables 4 and 5 , no significant difference in macular thickness between the two groups
the most common symptom in patients with brvo is a sudden loss of vision due to edema.2 there are two pathogenic mechanisms in macular edema secondary to brvo : starling force and increased vegf level.7,8 in brvo , there is an increase in intravascular pressure and plasma transudation into the extracellular space resulting in macular edema ( starling force).8 brvo also causes hypoxia in the retina .
therefore , the level of vegf , a vascular permeability factor , increases due to hypoxia , and this change will be excreted in the retina , leading to increase in retinal vascular permeability that worsens the macular edema that has already occurred as a result of the starling force.8,14 this occurs because the arteriovenous structure in the retina is a closed system with few collateral vessels .
if the obstruction occurs in the vein , it results in retinal ischemia.15 the anti - vegf antibody , bevacizumab , is a monoclonal antibody that binds to all vegf - a isoform .
bevacizumab inhibits vegf binding to its receptor such that capillary permeability is maintained and macular edema is reduced.9 the us food and drug administration has approved intravenous bevacizumab injection for colorectal cancer treatment .
however , intravitreal bevacizumab has been widely used and has been proven to be effective in inhibiting neovascularization in many retinal proliferative vascular diseases such as choroid neovascularization , proliferative diabetic retinopathy , neovascular glaucoma , and diabetic macular edema.1619 studies reported that intravitreal bevacizumab injection is not inferior compared to intravitreal ranibizumab injection , an intravitreal anti - vegf that has been approved by the us food and drug administration for the treatment of age - related macular degeneration.20,21 bevacizumab is also more cost - effective than ranibizumab.22 a study by solaiman et al17 on patients with diabetic macular edema given a combination treatment of macular laser therapy and anti - vegf bevacizumab compared to laser therapy alone showed a significant increase of visual acuity at the 1-month follow - up in the combination treatment group . at 1-month follow - up , the mean decreases of macular thickness were 49.88 m in the laser group and 110.30 m ( p<0.05 ) in the combination treatment group .
study on pro re nata bevacizumab to grid laser on brvo showed significant resolution of macular edema.16 that study was also similar to other studies that demonstrate the effectiveness of anti - vegf in retinal vein occlusion ( rvo ) ( shown in table 6).16,2327 another study showed that intravitreal bevacizumab injection resulted a better outcome in patients with diabetic macular edema compared to treatment with laser photocoagulation , such as in drcr and bolt study.18,28 laser photocoagulation is directed to the retinal pigment epithelium so that the oxygen can diffuse directly to the internal retinal layer through the laser scar .
when tissue hypoxia is relieved , the arterial resistance will increase and vein hydrostatic pressure will decrease such that plasma transudation will lessen and macular edema will resolve.29 based on the hypothesis that macular edema secondary to brvo causes decreased visual acuity , many efforts have been made to reduce macular edema to achieve improvement in visual acuity after brvo .
however , resolution of macular edema is followed by loss of photoreceptors that causes limited improvement of visual acuity .
these findings explain the limited visual acuity improvement in patients with macular edema secondary to brvo after laser photocoagulation treatment alone .
therefore , intravitreal bevacizumab injection as an adjuvant therapy in the early course of brvo is intended to maintain the physiologic integrity of both the internal and the external photoreceptor structure .
this combination treatment then leads to decreased macular edema and maximal improvement of visual acuity .
anti - vegf treatment in the early course of acute brvo can reduce vegf level to maintain vascular permeability , and as a result will reduce serous retinal detachment as a complication for macular edema .
laser photocoagulation therapy is considered unsafe if it is performed in the acute phase of brvo .
however , it should be performed within the first 3 months , because after that period , the macular edema may worsen and cause retinal cell damage and permanent loss of vision .
for that reason , in this study , bevacizumab was given at the beginning of the study , and the grid laser was done after most of the retinal hemorrhage was absorbed , but not later than 3 months . with this approach , maximal improvement of vision and decrease of macular thickness could be achieved .
the role of intravitreal bevacizumab in this study was intended to facilitate rapid macular edema resolution so that the laser grid can be performed sooner .
our results show that a single injection is sufficient to facilitate that process . in our result ,
the mean difference of visual acuity in the combination therapy group was 0.35 or greater than 15 characters in 1 month .
the result was similar at the 3-month follow - up ( table 2 ) . in laser therapy group ,
the mean difference of visual acuity was less than 15 characters at the 1-month follow - up and showed similar results at the 3-month follow - up ( table 4 ) .
the mean decrease in macular thickness in the combination therapy group and laser - only group showed no statistical difference at 1 month and 3 months ( figures 1 and 2 ) .
the increase of visual acuity was significantly different statistically between the two groups at 1 month and 3 months .
we believe , on the combination group , the anti - vegf had an effect on rapid resolution of the edema , due to which we could perform laser treatment immediately to reduce the oxygen consumption in the macula and decrease the vegf .
we believe this was also one of the factors that resulted in a significant increase in visual acuity in the combination group .
therefore , the effectiveness of a single injection in the long run has to be determined to rule out the rebound condition that might occur on brvo .
we could not get the data of the first 1-week period after diagnosis and the ischemic status of the brvo .
in conclusion , visual acuity improvement was better in laser photocoagulation therapy in combination with bevacizumab compared to that with laser photocoagulation therapy alone in macular edema secondary to brvo .
there was no difference in decrease of macular thickness between the two groups , hence a future study is needed with bigger sample size and longer follow - up period .
combination therapy of single bevacizumab and laser photocoagulation can be considered an alternative therapy for macular edema secondary to brvo . | backgroundmacular grid laser photocoagulation remains the standard treatment for macular edema secondary to branch retinal vein occlusion ( brvo ) .
one possible strategy for treating macular edema is to inhibit vegf activity by competitive binding of vegf with an anti - vegf antibody , suggesting the therapy option with bevacizumab .
however , multiple injections of anti - vegf may lead to complications and high cost.purposethe aim of this study was to evaluate the improvement in visual acuity and central macular thickness after combination therapy of laser photocoagulation with single intravitreal bevacizumab injection in macular edema secondary to brvo.methodsnineteen patients with macular edema secondary to brvo were assigned to either the group of nine patients in combination therapy of laser photocoagulation with intravitreal bevacizumab or the group of ten patients in the laser photocoagulation therapy .
complete ophthalmologic examinations were performed just before the therapy and at 1 month following the therapy .
changes in visual acuity were tested with the logarithm of minimum angle of resolution ( logmar ) , and central macular thickness was measured by optical coherence tomography ( oct).resultscombination therapy of laser photocoagulation and single intravitreal bevacizumab injection resulted in a significantly better visual acuity compared to laser photocoagulation therapy ( 0.35 versus 0.13 logmar ; p=0.041 ) and reduced macular thickness by 120.33 m versus 71.50 m ( p=0.277 ) , although this difference was not significant.conclusionlaser photocoagulation combined with a single intravitreal bevacizumab has a substantial effect on increasing visual acuity in macular edema secondary to brvo . |
familial mediterranean fever ( fmf ) has been characterized by fever
and recurrent aseptic inflammation of serosal spaces with a
typical familial tendency .
a lot of metabolic and immunologic changes happen
to occur in these patients during the attack
period .
acute phase reactants , such as
erythrocyte sedimentation rate ( esr ) , fibrinogen , and c - reactive
protein ( crp ) [ 2 , 3 ] , and pro - inflammatory cytokines , such as
interleukin-6 ( il-6 ) , have been found to be elevated during the
attacks [ 4 , 5 ] .
the close relationship between il-6 and fmf attacks is
without any debate , that serum il-6 shows meaningful increases
during these attacks [ 1 , 5 , 6 ] and colchicum treatment turns
il-6 levels down to normal values .
leptin is secreted from adipocytes , and after interaction with its
receptors , it controls body weight and daily energy consumption
[ 7 , 8 ] .
increasingly , data show that leptin has some
important role in the regulation of acute phase reaction .
also it is such an immunoregulatory substance which belongs to
class-1 cytokine family . indeed , leptin structurally
looks like granulocyte colony stimulating factor which is a member
of il-6 cytokine family .
adipocytes secrete leptin
and even il-6 in acute inflammatory
conditions . during this acute inflammatory response ,
serum leptin
levels have been shown to increase and possibly contribute to
anorexia and cachexia that accompany chronic infections .
interestingly , very low calorie diet in obese subjects leads to
mutual decrease in blood il-6 and leptin levels .
moreover , in septic subjects , serum il-6 and leptin levels
correlate very well . in this study , we plan to scrutinize whether or not leptin has any
role in triggering and/or regulation of inflammatory response in
fmf attacks .
accordingly , we investigated serum leptin levels
before and during acute attacks of fmf .
the mean age was
24.42 1.22 years ( range : 2052 years ) , and the gender distribution was 22 males
and 3 females .
inclusion criteria were as follows : fmf attacks
should have been started at least 1 year ago ; absence of systemic
diseases including chronic renal failure , diabetes mellitus ,
ischemic heart disease , malignancy , trauma , heavy exercise , and
infectious and inflammatory disorders ; and lack of any drug use
including colchicine with potential effects on the biochemical and
immunologic parameters during the last 4 weeks .
the control group
included 25 healthy people with a mean age 24.30 1.19 ( range :
2143 years ) .
blood samples were taken before attack and 812 hours after the
attack started in fmf cases .
we obtained blood samples from the
fmf patients and controls after 12 hours of fasting since serum
il-6 levels increase has been shown acutely stimulated by meals
.
moreover , concentration of circulating leptin is
reduced in starvation [ 18 , 19 ] .
the total blood count was measured by stks autoanalyzer
( hialeah , finland ) .
esr was measured by westergreen method on the same day
of obtaining samples , and esr within one hour was recorded .
the
rates of 015 mm / h for males and 020 mm / h for
females were considered to be within normal ranges .
crp
( biosystems sa , barcelona , spain ) levels were measured by
turbidimetric method after assessing absorbance at
bis-310 photometer ( berlin , germany ) , the levels equal
to or below 6 mg / l were considered to be normal levels .
fibrinogen levels were measured by a photo - optical method using
fibrinogen ( sigma diagnostics ) reagents in an
amelung amax 190 plus device ( taufkirchen , germany ) , and
200400 mg / dl were considered to be normal values .
serum
il-6 values were measured by immunotech enzyme
immunoassay kit ( westbrook , me ) ( cat 1120 , 96
tests ) , ( normal < 8 pg / ml ) .
serum leptin
analysis was performed by using
medizym leptin elisa kit ( medipan diagnostica , gmbh , selchow ,
germany ) in all patients and controls .
the statistical analysis was made by using spss 11.0
( chicago , ill ) in a personal computer .
groups were compared
according to independent sample t test , and the results of serum
leptin levels of presymptomatic and symptomatic periods were
compared by using paired t test .
there was no statistical difference in respect to age distribution
in between the controls and fmf study group .
out of 25 patients ,
23 had fever and signs of aseptic peritonitis , 12 had pleural
involvement , and 17 cases had joint inflammation .
the mean serum leptin concentration in control group was between
1.81 and 9.64 ng / ml ( mean sem : 4.282 0.385 ) . in
fmf group , it was 6.4528 1.05 ( range : 0.3220.55 ng / ml ) and
7.5928 1.3 ( range : 0.220.40 ng / ml ) before and during fmf attacks ,
respectively .
the mean serum leptin levels in the study group
before and during the attacks did not differ significantly from
that of the control group ( p > .05 ) .
although serum leptin levels
increased to some extent during the attacks , this was not
significant statistically ( p > .05 )
( figure 1(a ) ) .
however , serum leukocyte counts , sedimentation rate , and
c - reactive protein and il-6 levels were found to increase
significantly during the fmf attacks ( p < .05 )
( figure 1(b ) , figure 2 ,
table 1 ) .
there was an apparent correlation between
the body mass index and serum leptin levels ( r = 0.433 ,
p <
.05 )
before attacks figure 3 . we could not find a correlation between serum
leptin levels during attacks ( r = 0.326 , p > .05 ) .
there was no correlation
comparing serum leptin levels with the leukocyte counts ,
sedimentation rate , fibrinogen , crp levels and
serum il-6 ( p > .05 ) .
our aim was to define the role of leptin and find out if there is
any relationship between serum leptin and il-6 levels in a typical
systemic inflammatory condition like fmf .
though ,
we found that serum leptin levels increase during fmf
attacks , this increase was statistically not significant
( p > .05 ) .
however , serum leukocyte counts , fibrinogen ,
erythrocyte sedimentation rate , and c - reactive protein levels were
shown to increase significantly as expected .
additionally , we
could not find a correlation between serum il-6 and leptin levels .
acute inflammation can lead to elevated mouse serum leptin levels
and interestingly serum leptin levels in mouse has a trend to
increase even more after administration of il-6 .
leptin
levels are acutely increased by many acute phase factors , such as
tnf , il-1 , and il-6 , and during bacterial infection or
lipopolysaccharide challenge . moreover ,
leptin itself
was shown directly to induce the production of interleukin-6 and
other acute phase reactants .
additionally , leptin
might stimulate acute phase protein production through the il-6
dependent intracellular signaling pathway . moreover ,
there are some studies showing a correlation between leptin and
il-6 .
one of them indicated that there are clear correlations
between the serum levels of il-6 and leptin
( r = 0.45 , p < .05 ) tnf - alpha and leptin
( r = 0.49 , p < .05 ) in patients
with intra - abdominal sepsis during postoperative period .
similarly ,
in diabetic and nondiabetic obese persons , there were
significant correlations between leptin and il-6 and leptin and
bmi ( r = 0.841 , p < .05 ) .
after weight loss , serum leptin and il-6
concentrations decreased significantly in the same patient groups
.
we measured fibrinogen to discriminate the attack and attack - free
periods of the fmf patients [ 5 , 24 ] . in the present study
, we
could not detect any correlation between fibrinogen and leptin and
fibrinogen and il-6 ( p > .05 ) . on this background ,
it is very logical to consider leptin as a
participant in the inflammatory process associated with fmf .
however , our study could not indicate statistically significant
increase in serum leptin levels during the acute attack
periods .
furthermore , in the present study , serum leptin levels
before fmf attacks were found to correlate well with the body mass
indexes like some studies [ 2527 ] . however , there
were no statistically significant correlations between the body
mass indexes and serum leptin levels during the attacks . a
completely similar
finding has been reported in septic patients in
whom no correlation was found between these 2 parameters
.
this may be related to some unknown complicated
regulatory pathways for serum leptin levels during fmf attacks .
indeed , the activation of cytokine network in fmf is not based
extensively on il-6 and the interaction of the cytokine network is
rather complex .
similarly , a relevant literature indicates no
correlation between disease activity and serum leptin levels in
cases with romatoid arthritis [ 27 , 28 ] . as a conclusion , serum leptin levels do not increase statistically
significantly in fmf attacks and therefore it is not useful for
diagnostic purposes and/or follow - up during treatment .
( a ) leptin levels before ( mean sem :
6.4528 1.05 ng / ml ) and during ( mean sem :
7.5928 1.3 ng / ml ) the attacks in fmf patients .
serum
leptin levels did not increase significantly during the attacks
( p > .05 ) .
( b ) serum il-6 levels before
( mean sem : 70.18 14.8
correlation plot of
leptin before and during fmf attacks together with il-6 plot .
although serum leptin levels increased to some extent during the
attacks , it was not statistical significant ( p > .05 ) .
serum il-6
levels increased from 70.18 14.8 ( mean sem ) to
163.32 25.25 ( mean sem ) and they were
statistically significant ( p < .001 ) . correlation graph
between bmi and preattack leptin levels in fmf patient
( r = 0.433 , p < .05 ) . | the aim of our study is to determine whether there is a
relationship between familial mediterranean fever ( fmf ) attacks
and serum leptin levels .
we enrolled 25 patients ( 22 males and 3
females ) and 25 healthy controls ( 21 males and 4 females ) with a
mean age of 24.42 1.22 ( mean sem ) years and
24.30 1.19 years ( mean sem ) , respectively .
we
investigated serum levels of leptin , interleukin-6 ( il-6 ) ,
erythrocyte sedimentation rate ( esr ) , c - reactive protein ( crp ) ,
fibrinogen , and leukocyte counts before the attack and 812 hours
after the attack started .
the same parameters have been
investigated in the control subjects
. the mean serum leptin levels
before the attacks were 6.45 1.05 ( mean sem ) and during
the attacks were 7.59 1.3 ( mean sem ) in fmf group ,
respectively .
there was a slight increase in serum leptin levels
during the attacks but it was not statistically significant
( p > .05 ) .
the mean serum leptin levels were
6.12 2.81 in the control group which were not different from
the mean serum leptin levels before and during the attack periods
in the study group ( p > .05 )
. however , there were statistical
differences in the serum levels of il-6 , esr , crp , fibrinogen , and
leukocyte counts before and during the attack periods
( p < .05 ) .
no correlation was found between serum leptin levels and il-6 ,
esr , crp , fibrinogen , and leukocyte counts
( p > .05 ) . serum leptin
levels do not increase during fmf attacks and therefore it is not
useful for diagnostic purposes and follow - up during treatment . |
anaerobic bacteria especially black - pigmented gram - negative species have been linked to the signs and symptoms of periapical disease .
primary endodontic infections are polymicrobial in nature and are dominated by gram - negative anaerobic rods while secondary endodontic infections are composed of few bacterial species.[25 ] facultative bacteria like enterococcus faecalis is the most commonly isolated species from the root canals of the teeth with failed endodontic treatment and its prevalence in such infections ranges from 24% to 77% .
e. faecalis is gram - positive cocci that occur singly , in pairs or short chains , can survive harsh environments like extreme alkaline ph ( 9.6 ) and a temperature of 60c for 30 min .
it possesses certain virulence factors such as lytic enzymes , cytolysin , pheromones , and lipotechoic acid , suppresses the action of lymphocytes , potentially contributing to endodontic failure .
it is very small to invade and live within dentinal tubules and can endure prolonged periods of starvation .
when nutritional supply becomes available it can utilize serum as a nutritional source that originates from alveolar bone and periodontal ligament .
it has been shown to synthesize a variety of stress proteins when exposed to adverse environmental conditions . since , its introduction in 1920 by hermann
, calcium hydroxide has been widely used as intracanal medication for the treatment of apical periodontitis .
certain studies have indicated that killing of microbes in the canal can be achieved with calcium hydroxide . in a study of microbiology of root canals in retreatment cases , where calcium hydroxide - tolerant microbes were frequently isolated ,
it was suggested that alternative medicaments may be sometimes needed to resolve the infection to gain healing .
it is bacteriostatic while at higher concentration it is bactericidal as it brings about coagulation and precipitation of cytoplasm .
chx gluconate gel has been extensively used in dentistry mainly as an intracanal medicament . in this modern era of dentistry
use of plant parts as folklore medicine has been trailed by traditional healers since time immemorial . who has reported that 80% of world 's population relies mainly on traditional therapies .
there are many advantages of using herbs as antimicrobials : ( a ) they have fewer side effects ; ( b ) less expensive ; ( c ) better patient tolerance ; and ( d ) renewable in nature . throughout asia , traditional medicine
has long used turmeric as an anti - inflammatory , anti - oxidant , anti - microbial agent to deal with a wide range of conditions .
ajwain , the bishop 's weed containing thymol , the major phenolic compound renders it good germicidal and anti - fungal properties .
the purpose of this in vitro study was to evaluate the anti - microbial efficacy of curcuma longa ( turmeric t1 - 10% , t2 - 20% ) ; tachyspermum ammi ( ajwain a1 - 10% , a2 - 20% ) ; chx gluconate gel ( hexigel chx-1% ) and calcium hydroxide ( 10% ) as intracanal medicaments against e. faecalis .
six agar plates were prepared by using brain - heart infusion ( bhi ) agar ( titan biotech ltd .
agar was mixed according to manufacturer 's directions , and enough agar was poured to cover the surface of a 125 mm petridish .
the bhi agar dishes were then stored at room temperature for 2 days before use to verify that they had remained sterile .
bhi broth ( titan media ) was also prepared and stored in 5 ml vials for 2 days .
e. faecalis ( mtcc 2729 ) was maintained on bhi broth and cultures of e. faecalis were grown overnight at 37c in bhi broth for 24 h and bacterial growth was checked by presence of turbidity .
the bhi broth was inoculated with e. faecalis from a freshly grown culture on an agar plate .
the broth culture was incubated at 37c for 24 h. medicaments like c. longa ( turmeric ) were prepared in two concentrations of 10% ( t1 ) and 20% ( t2 ) by taking raw turmeric and grinding it into a coarse powder and then by adding sterile distilled water according to the required concentrations in two different test tubes .
similarly , t. ammi ( ajwain ) was prepared in two different concentrations in two different test tubes by adding sterile distilled water to ajwain crystals , thus , obtaining it in concentrations of 10% ( a1 ) and 20% ( a2 ) .
other medicaments that were used were calcium hydroxide ( nice chemicals , kochi , india batch 711330 ) , which was obtained in a powdered form and then made to 10% by adding sterile distilled water in a test tube .
gujarat , india , batch 0201920712 ) was also used as one of the medicaments .
. wells of 7 mm diameter and 4 mm depth were punched in agar plates and filled with 10 l of medicaments to be tested .
all manipulations of the specimens were performed under a laminar flow ( toshiba ) to avoid contamination .
it was observed that c. longa ( t2 - 20% ) showed significantly ( p < 0.05 ) more zone of microbial inhibition than c. longa ( t1 - 10% ) , t. ammi ( a1 - 10% and a2 - 20% ) and calcium hydroxide ( 10% ) .
hexigel ( chx-1% ) and c. longa ( t1 - 10% ) showed significantly larger zones of microbial inhibition than t. ammi ( a1 - 10% and a2 - 20% ) and calcium hydroxide ( 10% ) .
the size of zone of inhibition between c. longa ( t2 - 20% ) and hexigel ( chx-1% ) was not significant ( p > 0.05 ) .
t. ammi ( a1 - 10% and a2 - 20% ) and control group showed no microbial inhibition [ table 1 and figure 1 ] .
antimicrobial effect of intracanal dressing on enterococcus faecalis antibacterial activity of curcuma longa ( t1 - 10% , t2 - 20% ) , tachyspermum ammi ( a1 - 10% , a2 - 20% ) , chlorhexidine gluconate gel ( chx-1% ) and calcium hydroxide ( 10% )
complete elimination of microorganisms from the root canal is not possible despite antimicrobial properties of chemomechanical preparation and intracanal medicaments
. it could be because of anatomical complexities or may be due to varying vulnerabilities of involved species .
the most commonly isolated species from root canals of teeth with failed endodontic treatment is e. faecalis .
it can gain entry into the root canal system during treatment , between appointments or after root canal completion .
virulence factor of e. faecalis in failed endodontically treated teeth may be related to the ability of e. faecalis to invade dentinal tubules and adhere to collagen in presence of human serum . in this in vitro study , anti - microbial activity of various intracanal medicaments was compared to eliminate endodontic pathogen responsible for root canal failure .
e. faecalis in dentinal tubules has been shown to resist intracanal dressings of calcium hydroxide for over 10 days as it is shown to withstand a high ph . at ph 11.5 or greater e. faecalis
does not survive , yet it can survive at a ph below 11.5 . in radicular dentin , alkalinity may only reach ph 10.3 after dressing the canal with calcium hydroxide .
it forms a biofilm that helps it resist destruction by enabling the bacteria to become more resistant to phagocytosis and antimicrobials . even though calcium hydroxide does have some antibacterial action , but under the experimental conditions it was not able to kill and eliminate sufficient cells of e. faecalis at any time .
this is in accordance with findings of other reports by haapasalo et al . in the present study , chx in gel formulation at 1%
is a powerful anti - microbial agent , showing large inhibition zones , which ranged from 19 mm to 21 mm . although chx showed better anti - microbial activity
but its main drawback is that it does not act as a physical barrier , thus , staying in canal for a shorter period of time .
this is in accordance with the study by gomes et al . , which suggested that chx gel has a greater antibacterial activity against e. faecalis than calcium hydroxide but loses its property for longer periods .
various authors have shown the anti - microbial activity of c. longa against an array of pathogens . in the present study , it was found that c. longa turmeric ( t2 - 20% ) with a wide range of therapeutic action being anti - inflammatory , antibacterial , and antifungal showed highest zones of microbial inhibition ranging from 21 mm to 23 mm . the mechanism behind this has been explained by many authors on the basis of hypothesis , which states that it is due to bacterial cell wall perturbation .
although t. ammi ( ajwain ) in both 10% ( a1 ) and 20% ( a2 ) concentrations did not show any antimicrobial effect against e. faecalis .
with time plant extracts have been understood to encompass the attributes accounted not only for their fragrance and flavor , but also for their antimicrobial nature . in our study , c. longa ( t2 - 20% ) showed promising results in elimination of e. faecalis
one of the common organism responsible for root canal failure and is a good cost effective alternative to all the historical intracanal medicaments with fewer side effects and least resistance developed by the species .
however , further studies should be carried out to determine the use of turmeric as an intracanal medicament in endodontics . | aim and objectives : this in vitro study was designed to comparatively evaluate the antimicrobial efficacy of curcuma longa ( turmeric t1 - 10% , t2 - 20% ) ; tachyspermum ammi ( ajwain a1 - 10% , a2 - 20% ) ; chlorhexidine ( chx ) gluconate gel ( hexigel 1% ) ; and calcium hydroxide ( 10% ) as intracanal medicaments against enterococcus faecalis.materials and methods : agar plates were prepared using brain - heart infusion ( bhi ) agar .
cultures of e. faecalis were grown in bhi broth at 37c .
well diffusion method was used to derive results .
plates were inoculated for 72 h at 37c and microbial zones of inhibition were recorded .
statistical analysis was performed with repeated measures analysis of variance.results:c .
longa ( t2 - 20% ) and chx gluconate gel ( hexigel chx-1% ) showed larger zones of microbial inhibition than c. longa ( t1 - 10% ) that were statistically significant ( p < 0.05 ) and were highly significant when compared to t. ammi ( ajwain a1 and a2 ) and calcium hydroxide.conclusion:c .
longa can be used as intracanal medicament in endodontic failure cases . |
application of gics in conjunction with composite resin is a conventional restorative method known as the sandwich technique .
this technique combines the optimal properties of composite resins ( i.e. optimal esthetics and wear resistance ) with those of gics ( i.e. durable bond with dentin and long term release of fluoride ) . in order to achieve a successful sandwich technique restoration ,
a strong bond between the composite resin and the gic is required to overcome the internal stresses related to the setting of the composite resin and the clinical stresses imposed in long - term .
numerous factors affect the quality of the bond between the composite resin and the conventional gics which include the time elapsed between mixing the cement and etching , the etching time , type of cement , application of an intermediate unfilled resin and the properties of the unfilled resin such as wettability and texture .
the bond between the conventional gic and composite resin is micromechanical and achieved through irregularities developed on the surface of the gic during the bonding procedure ( i.e. similar to bonding composite resin to dental hard tissues ) .
it was demonstrated that rapid etching of the newly set gic may compromise its mechanical properties and bond strength ; whereas delaying the etching by up to 24 hours post application of cement improved the bond strength .
since long deferment is impractical , researchers have proposed the application of resin - modified gics , to form a direct chemical bond between the methacrylate components in both materials within a shorter period of time .
currently , there is an increasing trend toward the use of self - etch bonding systems .
these systems contain acidic monomers , which are capable of concurrent etching and priming , eliminating the need for extra steps of etching and rinsing .
this reduces technique sensitivity and the overall duration of the procedure resulting in improved clinical efficacy .
although numerous studies have been carried out on different properties of sandwich restorations including bond strength , microleakage and the clinical efficacy of this technique , the majority of these studies have studied the etch and rinse bonding systems .
conducted a study on the bonding application time in association with the microleakage of class v sandwich restorations and revealed that time did not affect microleakage at the occlusal margins ; whereas , in the gingival margins , microleakage decreased with time .
however , there is limited information regarding the effect of bonding application time in self - etch systems on the bond strength between gics and composite resins .
thus , the present study sought to evaluate the effect of etching time and the application of self etch bonding systems on the microshear bond strength between composite resins and gics .
the present in vitro study involved the use of four types of gics : two resin - modified gics namely riva light cure ( sdi ) and fuji ii lc ( gc international ) , and two conventional gics namely riva self cure ( sdi ) and fuji ii ( gc international ) , two bonding systems namely an etch & rinse stea ( sdi ) and self etch frog ( sdi ) and a light cure composite resin ( z100 , 3 m espe ) . table 1 lists the materials evaluated in this study .
a total of 160 gic specimens were made using molds with dimensions of 246 mm .
materials evaluated in this study the gics were prepared according to the manufacturers instructions . after filling the molds with the cement , the surface
was covered with a mylar strip and a glass slab was placed on top of them to achieve a smooth surface .
the surface of the conventional gics was then prepared using the stea and frog bonding systems at three time points ( after working time , immediately after setting and 15 minutes after mixing ) .
the resin - modified gics were also etched using the two bonding systems immediately after curing .
study groups and microshear bond strength values of gics 10 specimens in each group sd : standard deviation for the etch & rinse group ( stea ) , the surface of the gic blocks was initially etched with 37% phosphoric acid for 15 seconds , rinsed ( 10 seconds ) and moist - dried .
the bonding was then applied and cured for 40 seconds using arialux ( 650 mw / cm ) light curing unit ( apadanatak , tehran , iran ) . for the self - etch group ( frog ) , the surface of the gic blocks
was initially treated by the primer for 10 seconds and gently dried with air spray .
the bonding agent was then applied using a fine applicator and gently dried and cured for 10 seconds .
finally , z100 composite resin ( a2 ) in plastic tubes ( tygon tubes ) with an internal diameter of 0.7 mm and height of 1 mm was placed on the surface of the gic holding the tube perpendicular to the specimens .
the composite was cured for 40 seconds and subsequently stored in distilled water ( 37c ) for 24 hours .
the tubes were then cut using a scalpel and removed from around the composite resins . to evaluate the microshear bond strength ,
the samples were placed in a microtensile tester ( bisco , schaumburg , il , usa ) and subjected to microshear stress at a crosshead speed of 1 mm / min .
the force needed to break the samples was recorded in newton and the microshear bond strength was calculated by dividing the maximum force by the surface area of the specimens ( mpa ) .
level of significance was set at p<0.05 . to assess the surface characteristics of glass ionomers after different treatments under scanning electron microscope ( sem ) ,
each specimen was treated the same as its corresponding group ; the only difference was that on these specimens no adhesive resin was applied .
for the etch & rinse group ( stea ) , the surface of the gic blocks was initially etched with 37% phosphoric acid for 15 seconds , rinsed ( 10 seconds ) and moist - dried .
the bonding was then applied and cured for 40 seconds using arialux ( 650 mw / cm ) light curing unit ( apadanatak , tehran , iran ) . for the self - etch group ( frog ) , the surface of the gic blocks
was initially treated by the primer for 10 seconds and gently dried with air spray .
the bonding agent was then applied using a fine applicator and gently dried and cured for 10 seconds .
finally , z100 composite resin ( a2 ) in plastic tubes ( tygon tubes ) with an internal diameter of 0.7 mm and height of 1 mm was placed on the surface of the gic holding the tube perpendicular to the specimens .
the composite was cured for 40 seconds and subsequently stored in distilled water ( 37c ) for 24 hours .
the tubes were then cut using a scalpel and removed from around the composite resins . to evaluate the microshear bond strength ,
the samples were placed in a microtensile tester ( bisco , schaumburg , il , usa ) and subjected to microshear stress at a crosshead speed of 1 mm / min .
the force needed to break the samples was recorded in newton and the microshear bond strength was calculated by dividing the maximum force by the surface area of the specimens ( mpa ) .
level of significance was set at p<0.05 . to assess the surface characteristics of glass ionomers after different treatments under scanning electron microscope ( sem ) ,
each specimen was treated the same as its corresponding group ; the only difference was that on these specimens no adhesive resin was applied .
table 2 illustrates the microshear bond strength values in conventional gics treated with the two bonding systems at different times .
the multivariate effect of the two brands of gics , two bonding systems and the three different times on the microshear bond strength was assessed using the three - way anova .
the test results failed to reveal a significant three - way combined effect of the covariates or the interaction effect of the gic - bonding agent and the gic - time on the bond strength .
however , the cross - effect of the bonding and time was significant ( p<0.05 ) .
in other words , microshear bond strength at different intervals was shown to be affected by the type of bonding agent .
on the other hand , the type of gic markedly affected the bond strength ( p<0.001 ) .
the results yielded significantly higher bond strength in fuji ii compared to riva self cure , regardless of the type of bonding agent and time . to further evaluate the correlation between the bonding material and time
, the effect of the two factors on microshear bond strength was calculated using the two - way anova .
it was observed that in the riva self cure group , the type of bonding agent failed to affect the bond strength ( p=0.365 ) , while the bonding application time significantly affected the bond strength ( p<0.05 ) .
test for pairwise comparison of the bonding application times revealed that the maximum bond strength was achieved with immediate application of the bonding agent while the minimum bond strength was achieved when the bonding agent was applied 15 minutes after mixing . in the fuji ii group , the time and type of bonding agent had no effect on the microshear bond strength .
table 2 summarizes the microshear bond strength values of resin - modified gics relative to the type of bonding agent .
two - way anova was applied to compare the microshear bond strength values between the two brands of resin - modified gics ( fuji ii lc and riva light cure ) and to assess the effect of type of bonding system on microshear bond strength .
the statistical analyses revealed no significant interaction effect between the type of bonding agent and the type of resin - modified gic .
furthermore , applying either of the two bonding systems on the two brands of gics failed to result in different bond strength values .
this suggested that the type of bonding material had no significant effect on the microshear bond strength .
however , the type of resin - modified gic demonstrated a significant effect on the shear bond strength ( fuji ii lc exhibited higher microshear bond strength compared to riva light cure)(table 1 ) .
however , it was recognized that fuji ii yielded a more irregular and coarse surface than riva self cure at all time points ( figs .
in addition , self etch primer made a different surface with lower roughness in comparison with phosphoric acid as seen on sem micrographs ( figs .
fewer irregularities were seen on their surfaces after etching or priming ; in other words , a smoother surface was observed in all samples ( figs .
sem micrographs of self cure gics treated with phosphoric acid sem micrographs of self cure gics treated with self etch primer sem micrographs of light cure gics
application of gic under composite restorations ( sandwich technique ) is a common restorative procedure , with the desired properties of both materials . to attain optimal results ,
adequate bond strength is required between the composite resin and the gic to resist the stresses developed during the setting of the composite and over long - term clinical service .
for the first time , mclean et al . attempted to etch the surface of the gic via phosphoric acid and used resin bonding agent to bond composite to gic .
generally , etch and rinse bonding systems have widely been used in sandwich technique restorations .
however , given the nature of the tooth structure and properties of dentin , this system presents problems such as inadequate etching , rinsing and drying and compromised bonding ability .
thus , with the introduction of self - etch systems , researchers tried to overcome these shortcomings .
one of the major concerns of clinicians with regard to the use of sandwich technique is the time of bonding application .
a considerable amount of time may be required for complete setting of the gic and its favorable properties .
lund et al . believed that contamination of gics with moisture prior to complete maturation , results in increased solubility and decreased mechanical resistance of the substance .
this study was , therefore , conducted to evaluate the effect of bonding application time on the bond strength between gic and the composite resin and the possibility of applying the bonding agent at the early stages of setting while achieving optimum properties .
the results revealed that fuji ii and fuji ii lc displayed higher microshear bond strength compared to riva self cure and riva light cure .
this difference may be due to possibly higher strength of fuji ii compared to that of riva as it has been stated that bond strength is a function of cohesive strength of a material .
the other factor , which may account for the higher bond strength of fuji ii is the rougher surface of this material as revealed on sem micrographs ( figs .
unfortunately , the available data fail to allow for direct comparison between the two brands .
the highest bond strength was achieved immediately after working time and the lowest bond strength was recorded 15 minutes after mixing the cement . in other words ,
the bond between riva self cure and the composite resin became weaker with time and maturation of the cement .
therefore , it may be legitimate to assume that with complete setting and maturation of the material , the solubility of the cement decreases significantly resulting in reduced porosity and micromechanical retention and ultimately reduced bond strength .
this may explain why in the early stages of mixing when the cement had not reached complete maturation it demonstrated greater solubility in acid and was likely to provide optimum surface roughness and porosities for a stronger bond .
in fact , sem micrographs supported these findings in which the roughest surface was seen when riva self cure was etched after working time ( fig .
, it may be appropriate to claim that as fuji ii reaches maturation at a faster rate , its solubility is not significantly affected by time .
therefore , we tend not to see any significant differences in the bond strength at different times . riva self cure , on the other hand , undergoes maturation at a slower rate ; hence it demonstrates greater solubility in the early stages of maturation and gradually becomes less soluble rendering less surface roughness with time and resulting in compromised bond strength .
actually , sem micrographs showed that etching of riva self cure in early stages made a rougher surface ( figs .
1a , 1b and 1c ) in contrast , the rough surface of fuji ii exhibited an identical pattern at all time points ( figs . 1d , 1e and 1f ) .
evaluated the microleakage of class v sandwich restorations and concluded that in all self - cure gics treated with the total - etch bonding system , microleakage significantly decreased in gingival margins over time .
this was in line with the findings of the current study showing that when the cement is exposed to acid at early stages of maturation , greater surface roughness would be achieved rendering a stronger bond and less microleakage .
gemalmaz et al , and oilo reported that gics displayed minimum solubility six to seven minutes after the initiation of the setting reaction , and the solubility decreased with time and maturation of the cement .
furthermore , hamouda showed that there was a direct correlation between solubility and surface roughness .
our results also revealed that resin - modified gics developed a stronger bond compared to the conventional ones .
the residual unpolymerized hema molecules on the surface of the set resin - modified gic can facilitate wetting by the bonding agent and the composite resin during the bonding procedure .
furthermore , the presence of unreacted methacrylate groups within resin - modified gics and presence of oxygen inhibition layer on the surface can develop a strong chemical covalent bond with the bonding resin , which enhances the bond strength of gics [ 2123 ] .
moreover , due to the higher cohesive strength of resin - modified gics versus the conventional gics , the former cements display greater cohesive strength , which may account for this difference .
resin - modified gics set faster due to their light curing mechanism ; therefore , the effect of etching or priming systems on the surface of these cements significantly differs from that of conventional gics . the smooth surface of resin - modified gics as seen on sem micrographs support a faster setting and , in turn , less solubility ( fig .
3 ) this study failed to show any difference in terms of the bond strength among the two bonding systems , i.e. self - etch and etch and rinse .
thus , based on a previous study by zhang et al , reporting a stronger bond between self - etch bonding systems and conventional gics compared to etch and rinse systems , it may be concluded that the new generations of bonding systems can be readily used in sandwich technique restorations .
based on the findings of the present study , postponing the application of the new generations of bonding systems on gics to achieve more optimal results , is unnecessary and fails to affect the bond strength of composite resin to gics . | objectives : this experimental study evaluated the effect of bonding application time on the microshear bond strength of composite resin to different types of glass ionomer cements ( gics).materials and methods : one - hundred and sixty specimens ( two conventional and two resin - modified gics ) were prepared and divided into 16 groups .
the surface of all specimens was prepared using two different bonding systems ( frog and stea ) at three different times . after setting , the composite resin ( z100 )
was placed over the gics .
the specimens were then stored in distilled water for 24 hours ( 37c ) and exposed to microshear stresses at a crosshead speed of 1 mm / min .
the results were analyzed using three - way anova and tukey s test ( p<0.05).results : in conventional gics , bond strength was affected by the type of bonding system at different times , and bond strength was significantly higher in the fuji ii group compared to riva self cure group . in the riva self cure group , bond strength was significantly affected by time ; whereas , the type of bonding system failed to exert a significant effect on bond strength .
there was no significant correlation between the type of bonding system and the two brands of resin - modified gics .
bond strength was not affected by the type of bonding agent ; however , among the two brands of resin - modified gics , fuji ii lc yielded a significantly stronger bond.conclusion:it appears that the type of bonding agent does not affect the microshear bond strength , and the bonding application time affects the microshear bond strength in riva self cure gics . |
the study took place in sweden from march 14 , 2005 through march 14 , 2008 at 5 hospitals that had infectious diseases departments .
inclusion criteria were travel within the past 2 months to a malaria - endemic area as defined by the world health organization , age > 18 years , documented temperature > 38c at admission or within the previous 2 days , and a decision by the examining clinician to obtain a blood film for suspected malaria .
participants were identified either through prospective case finding at emergency rooms and outpatient clinics or through retrospective case finding of eligible patients who had not been included in the prospective case finding ; these patients were identified through listings of all performed malaria diagnostics .
all included patients had been subject to diagnostic investigations ( e.g. , cultures , serologic analysis , radiographs ) on the basis of clinical symptoms and signs as part of routine procedures at each hospital .
an infectious diseases specialist at each study site confirmed the diagnosis based on results of investigations performed .
the following variables were recorded for all patients : age , gender , travel history ( destination , duration , and purpose ) , diagnosis , and if applicable , days of hospitalization .
information about pretravel immunizations and time between return to sweden and onset of symptoms was available only in the group of prospectively included patients .
purpose of travel was divided into 3 categories : tourism , swedish residents originating from a malaria - endemic country and visiting friends and relatives in their country of origin , or other .
paired serum samples from prospectively included patients were blindly analyzed for antibodies to influenza a and b viruses , dengue virus , chikungunya virus , brucella spp .
if the travel destination was asia , orientia tsutsugamushi and japanese encephalitis virus were also analyzed ( figure ) . a > 4-fold rise in reciprocal antibody titer against a relevant pathogen
comparisons between 2 groups were made by using univariate statistics ( test ) ; a p value < 0.05 was considered significant .
flow chart of serologic methods performed blindly on all paired serum samples ( n = 383 ) , sweden .
ig , immunoglobulin ; mat , microscopic agglutination test ; if , immunofluorescent . in 1,432 febrile travelers ,
a total of 514 patients were identified through prospective case - finding , and 383 of those agreed to be further tested by using blinded serologic analysis ; 918 patients were retrospectively identified .
characteristics of these groups are shown in table 1 . among the entire group ( n = 1,432 ) before results of additional blinded serologic analysis
were obtained , unknown fever was diagnosed in 34% , febrile gastroenteritis in 24% , malaria in 6% , influenza in 3% , and dengue fever in 2.5% . in the 383 prospectively included patients , the diagnosis was unknown fever in 115 ( 30% ) ; additional serologic analysis established a diagnosis in 24 ( 21% ) of these patients .
vfr , visiting friends and relatives ( swedish residents who were born in a malaria - endemic country and who had visited friends and relatives in their country of origin ) ; na , not applicable .
the most common diagnosis was influenza ( n = 12 ) followed by sfg rickettsial infection ( n = 5 ) , dengue fever ( n = 3 ) , leptospirosis ( n = 2 ) , q fever ( n = 1 ) , and rickettsial infection caused by o. tsutsugamushi ( n = 1 ) .
a positive serologic result added a co - infection to 23 patients with a diagnosis of illness other than unknown fever ; these co - infections were influenza ( n = 14 ) , dengue fever ( n = 3 ) , typhus group rickettsial infections ( n = 2 ) , sfg rickettsial infection ( n = 2 ) , leptospirosis ( n = 1 ) , and chikungunya fever ( n = 1 ) .
all infections diagnosed by additional blinded serologic analysis were mild and self - limiting , and the main symptom was fever without typical clinical signs .
fever of unknown etiology was diagnosed in 24% and influenza in 9% of the patients with additional serologic analysis , compared with 35% and 4% , respectively , in the group with routine investigations only ( table 2 ) . *
thirty - six patients in the prospectively included group ( n = 514 ) had influenza diagnosed by both routine examination and additional serologic analysis .
eighteen of the 36 became ill with fever either just before returning to sweden or within 1 day of arrival , indicating that they acquired the infection abroad ; 5 had been home 12 days , indicating that the infection could have been acquired either during travel or after the return ; and 13 patients had returned from travel > 3 days before falling ill with fever , indicating that they most likely became infected in sweden .
twenty - five of the 36 influenza patients had verified influenza a infection , and 11 had influenza b infection .
nine ( 25% ) patients became ill after returning from a trip occurring well outside the influenza season of the northern hemisphere ; 7 had visited africa , and 2 had traveled to asia .
our findings highlight the role of travel in the global spread of influenza and corroborate the findings of influenza in travelers by others ( 12,13 ) . apart from influenza , the most common diseases missed in routine investigations were rickettsial infections , dengue fever , and leptospirosis .
our study adds a new approach by using a systematic collection of paired sera . the retrospective case finding is not fully comparable with the prospective inclusion of patients , and we are missing some retrospective data on type and length of travel .
these missing data are , to some extent , compensated by a careful retrospective review of all 918 patients files , the finding that the characteristics of the 2 groups are similar , and the similarity of the routine investigations for both groups .
additional blinded serologic analyses were performed by using the same method in the same laboratories .
the proportion of final diagnoses with fever of unknown etiology was high compared with that of other studies , even after results of the additional serologic analysis ( 18,11 ) .
this large proportion of fever with unknown etiology may be explained by the unselected study population in a hospital setting and by a high patient turnover ; febrile travelers with a negative malaria film and in good clinical condition are often sent home without extensive investigations or follow up . to estimate the number of nasopharyngeal swabs taken as a routine test
, we retrospectively reviewed a sample of 217 patient files and found that 31 ( 14% ) had been tested for influenza ; 6 of those tests yielded positive results .
age , gender ratio , destinations , duration of travel , and hospitalization rates were similar to those of recent studies ( 3,7,8 ) .
the finding of undiagnosed rickettsial infections shows that symptoms are often nonspecific , and serologic response often delayed ( 14 ) .
our results indicate that leptospirosis is an underestimated cause of fever in returned travelers and is not only related to extreme sports ( 15 ) .
the relatively low frequency of additional rickettsial infections , dengue , and leptospirosis indicates that paired sera should not be routinely recommended without a specific clinical suspicion .
however , this study supports the theory that diseases with classic clinical findings according to text books can also manifest as fever only .
influenza should always , in all seasons , be considered when diagnosing illness in returning febrile travelers . | we studied 1,432 febrile travelers from sweden who had returned from malaria - endemic areas during march 2005march 2008 . in 383 patients , paired serum samples
were blindly analyzed for influenza and 7 other agents . for 21% of 115 patients with fever of unknown origin ,
serologic analysis showed that influenza was the major cause . |
parkinson 's disease ( pd ) is a movement disorder characterized by tremor , rigidity , slowness of movement , and postural imbalance .
there is evidence of abnormalities in the vitamin d - endocrine system in pd patients , including low bone mineral density ( bmd ) , decreased vitamin d levels , and increased bone turnover makers ( bone alkaline phosphatase and urinary n - terminal telopeptide of type i collagen ) compared to controls .
these factors , combined with balance problems , are the probable reasons for the high incidence of fractures , especially of the hip , reported in elderly women with pd .
sunlight exposure can increase the bmd of pd by increasing serum 25-hydroxyvitamin d3 ( 25ohd ) levels . in another study ,
the bmd z - score of the trochanter was directly correlated to the degree of physical activity and total body bmd z - score correlated to the degree of rigidity .
osteoporosis and osteopenia are common findings in pd patients , affecting up to 91% of women and 61% of men . decreased bmd , low concentrations of serum ionized calcium , and compensatory hyperparathyroidism increase the risk of hip fracture in pd patients . despite an abundance of correlational studies
, it is unknown whether vitamin d deficiency is a cause or consequence of pd . in the present paper ,
significantly increased levels of mhc class ii expressions were detected in the cerebrospinal fluid ( csf ) monocytes of pd patients .
human leukocyte antigen ( hla ) genes have also been implicated in pd , and large numbers of hla - dr - positive reactive microglia were detected in the substantia nigra ( sn ) and the nigrostriatal tract in pd patients [ 7 , 8 ] .
hla - dr - positive microglia have also been found in these regions in a case of parkinson's - associated dementia in guam .
conversely , calcitriol ( 1,25-dihydroxyvitamin d3 ) is known to stimulate phagocytosis but suppress mhc class ii antigen expression in human mononuclear phagocytes [ 9 , 10 ] .
calcitriol also decreases interferon - gamma - induced hla - dr antigen expression on normal and transformed human keratinocytes [ 11 , 12 ] .
these findings suggested that vitamin d may modulate mhc class ii antigen expression in pd .
vdr and 1-hydroxylase , the enzyme responsible for the formation of active vitamin d in the human brain , are found in the large neurons of the sn , as well as in neurons and glial cells in the hypothalamus .
vdr , a nuclear receptor , is restricted to the nucleus but 1-hydroxylase is distributed throughout the cytoplasm .
the presence of these proteins in the cns suggests that vitamin d is active within the brain .
genetic studies provide an opportunity to link molecular variations with epidemiological data , dna sequence variations , such as polymorphisms , exert subtle biological effects on the expression and functionality of proteins .
vdr mrna was identified as a potential blood marker for pd . in a korean population ,
butler et al . reported that the vdr gene is a potential susceptibility gene for pd in the caucasian population .
cyp superfamily of enzymes is responsible for the oxidation , peroxidation , and/or reduction of vitamins , steroids , and xenobiotics , as well as the metabolism of drugs .
cyp2d6 , an important member of this superfamily , is expressed in neurons in the brain and gut and may be influenced by polymorphic expression .
there is a higher prevalence of the poor - metabolizing cyp2d6 * 4 allele in pd patients compared with controls ( 20.7% versus 11.0% ) . in case - control and meta - analysis studies ,
the cyp2d polymorphism was found to be associated with pd [ 19 , 20 ] .
other studies , however , did not find an association between the cyp2d6 polymorphism and pd in an asian population [ 21 , 22 ] .
although the poor metabolizer genotype has a small but highly significant association with pd , it would be easily missed in studies with modest numbers of subjects .
protein and enzymatic activity are completely absent in less than 1% of asian people and in up to 10% of caucasians with two null alleles .
singh et al . reported the expression of cyp2d22 , an ortholog of human cyp2d6 , in mouse striatum and its modulation in mptp - induced pd phenotype and nicotine - mediated neuroprotection .
cyp2d6 is a potential 25-hydroxylase , which converts vitamin d3 into 25ohd , and vitamin d 25-hydroxylase deficiency resulted in vitamin d deficiency .
moreover , the cyp2d and pd loci are located on the same chromosome 22 [ 26 , 27 ] . deletion of chromosome 22q11 syndrome was reported to be associated with pd [ 28 , 29 ] .
interestingly , patients with a deletion of chromosome 22q11 showed a reduced bmd , serum calcium , and pth levels ; 11% and 8% of these patients had serum 25ohd levels under 20 ng / ml and abnormal serum 1,25ohd levels , respectively .
the primary function of the ras is to maintain fluid homeostasis and regulate blood pressure .
several components of the ras and its receptors are found in the cns [ 3134 ] , suggesting that ras is important in the brain .
csf levels of angiotensin - converting enzyme ( ace ) activity were reported to be decreased in pd patients and increased with dopaminergic treatment [ 35 , 36 ] .
in addition , the ace inhibitor perindopril has been shown to exert beneficial effects on the dopaminergic system [ 37 , 38 ] .
after four weeks of treatment with perindopril , patients with pd had faster improvement in motor response after l - dopa and a reduction in on phase
the frequency of the homozygous dd genotype of the ace gene was significantly increased in patients with pd , and is also higher in pd patients with l - dopa - induced psychosis versus without psychosis [ 40 , 41 ] .
however , other studies did not reveal any associations between ace polymorphisms , pd , and of l - dopa - induced adverse effects [ 42 , 43 ] .
the use of ace inhibitors by the ace dd genotype has been shown to decrease the level of calcitriol .
in addition , genetic disruption of the vdr resulted in overstimulation of the ras with increased production of renin and angiotensin ii , thereby leading to high blood pressure and cardiac hypertrophy .
treatment with captopril reduced cardiac hypertrophy in vdr knockout mice , suggesting that calcitriol may function as an endocrine suppressor of renin biosynthesis .
ho-1 is a stress protein that may confer cytoprotection by enhancing catabolism of pro - oxidant heme to the radical scavenging bile pigments , biliverdin , and bilirubin .
the ho-1 gene can be upregulated by a host of noxious stimuli and is induced in cns tissues affected by neurological diseases . in the normal brain ,
basal ho-1 expression is low and restricted to small groups of scattered neurons and neuroglia . in the brains of pd patients ,
the ho-1 is highly overexpressed in astrocytes within the sn and in lewy bodies found in affected dopaminergic neurons .
serum ho-1 levels are increased in pd patients but not in patients with alzheimer 's disease ( ad ) , suggesting a systemic antioxidant reaction to a chronic oxidative stress state that is unique to pd .
similarly , calcitriol delayed of ho-1 immunoreactivity after the postlesional survival time of 12 hours concomitant with a reduction in glial fibrillary acidic protein immunoreactivity in remote cortical regions affected by a secondary spread of injury in glial cells of the focal cerebral ischemic , thereby supporting the protective role of calcitriol in postcellular injury .
parp-1 is a nuclear protein that can promote either neuronal death or survival under certain stress conditions .
overexpression of parp-1 has been reported in the dopaminergic neurons of the sn in pd .
mptp is a neurotoxin that induces parkinsonian symptoms in human and animals , but mice lacking parp gene are spared from mptp neurotoxicity .
therefore , parp inhibitors have proved to be valuable tools in pd model [ 55 , 56 ] .
in addition , increased levels of vitamin d seem to downregulate parp-1 expression ; parp-1 levels decrease following calcitriol treatment in nb4 cells , which represent an acute promyelocytic leukemia cells .
vitamin d exerts a concentration - dependent inhibitory effect on parp-1 in the human keratinocyte cells .
vitamin d - induced downregulation of parp is further enhanced by nicotinamide in human myeloblastic leukemia cells .
furthermore , parp is attenuated in the hippocampus of rats that received dexamethasone and vitamin d , suggesting that the anti - inflammatory effects of dexamethasone and vitamin d derives from their ability to downregulate microglial activation .
these findings suggested that vitamin d may have a protective role in pd by downregulating parp .
ntfs can exert protective or even restorative effects on pd animal models and dopaminergic cell cultures ; key examples include brain - derived neurotrophic factor ( bdnf ) , glial - derived neurotrophic factor ( gdnf ) , mesencephalic - astrocyte - derived neurotrophic factor ( manf ) , and cerebral dopamine neurotropic factor ( cdnf ) .
receptors for these ntfs are expressed in the striatum and sn [ 67 , 68 ] .
ntf expression is reduced in the sn of patients with pd [ 6971 ] . moreover ,
the c allele of an inotropic cdnf single nucleotide polymorphism ( rs7094179 ) has been suggested to infer susceptibility to pd in a korean population , and a allele of bdnf is associated with pd in a chinese han population .
interestingly , calcitriol regulates the expression of the low - affinity neurotrophic receptor and increases striatal gdnf mrna and protein expression in adult rats .
in vivo , calcitriol is also a potent inducer of gdnf in rat glioma cells .
the brains of offspring from vitamin d - deficient dams are characterized by diminished expression of neurotrophic factors .
furthermore , calcitriol protects against dopamine loss from 6-hydroxydopamine- ( 6-ohda- ) lesioned rats by increasing gdnf and partially restores tyrosine hydroxylase expression in sn and striatum [ 78 , 79 ] .
sp1 transcription factor is a member of an extended family of dna - binding proteins that is acetylated in response to oxidative stress in neurons .
the sp1 family of proteins plays an important role in controlling the expression of the dopamine transporter gene within dopaminergic neurons and also regulates expression of rat dopamine receptor gene . on the other hand , binding sites for the transcription factor sp1
in cultured human fibroblasts , the level of cyp24 ( 25-ohd 24-hydroxylase ) mrna plays a key role in the metabolism of 1,25ohd and increases up to 20,000-fold in response to calcitriol .
two vitamin d - responsive elements ( vdres ) located upstream of the cyp24 gene are primarily responsible for the increased mrna levels , and sp1 acted synergistically with these vdres for the induction .
the mvdr promoter is controlled by sp1 sites and functions as the transactivation component of the vdr / sp1 complex to trigger gene expression . moreover
, the genes encoding sp1 and vdr were mapped to human chromosome 12q [ 75 , 76 ] .
a link between dm and pd has been suggested in several reports , but the results have been inconsistent .
insulin receptors and their mrnas are localized in the sn [ 83 , 84 ] . a high incidence of abnormal glucose tolerance has been reported in pd and seems to be exacerbated by l - dopa treatment .
dm has been associated with the risk of developing pd [ 86 , 87 ] whereas others reported from protective to no associations with pd [ 8890 ] .
human and experimental animal studies , however , demonstrated neurodegeneration associated with peripheral insulin resistance . in a 6-ohda model of pd , striatal insulin resistance was observed in the striatum , and patients with pd exhibited increased autoimmune reactivity to insulin .
individuals newly diagnosed with pd display reduced insulin - mediated glucose uptake , which is hypothesized to be due to inhibit early insulin secretion and hyperglycemia after glucose loading . furthermore , chronic hyperglycemia decreased limbic extracellular dopamine concentrations and striatal dopaminergic transmission in streptozotocin - induced diabetic rats [ 96 , 97 ] .
vitamin d levels may provide a link between the diseases ; serum 1,25ohd and 25ohd levels are low in diabetic patients [ 98 , 99 ] , and diabetic rats had an increased metabolic clearance rate of 1,25ohd . interestingly , a significant high prevalence of vitamin d insufficiency is reported in patients with pd [ 101 , 102 ] . a significant inverse association between serum vitamin d and pd was demonstrated and suggested that high vitamin d status might provide protection against pd . in diabetic - induced rats , vitamin d and insulin treatment markedly recovered the levels of altered gene ( cholinergic , dopaminergic , and insulin receptors ) expression and its binding parameters nearly to those of the control rats .
maternal vitamin d deficiency was reported to alter the expression of genes involved in dopamine specification in the developing rat mesencephalon .
calcitriol has been shown to protect dopamine neuronal toxicity induced by 6-ohda and the combination of l - buthionine sulfoximine and mptp , thereby restoring motor activity in the lesioned animals [ 106 , 107 ] .
furthermore , vitamin d was reported to improve rigidity and akinesia and reduce levodopa dosage in a patient with pd . unlike most neurons in the brain , dopaminergic neurons function as autonomous pacemakers that rely on l - vscc to generate action potentials at a clock - like 24 hz in the absence of synaptic input .
l - vscc activity during autonomous pacemaking increased the sensitivity of dopaminergic neurons to mitochondrial toxins in an animal model of pd .
epidemiological data supports a link between l - vscc functioning and the risk of developing pd [ 111113 ] .
pretreatment with the calcium channel antagonist nimodipine has been shown to block the development of mptp - induced neurotoxicity in animal models [ 114 , 115 ] .
israpidine , another l - vscc antagonist , caused a dose - dependent reduction in l - dopa - induced rotational behavior and abnormal involuntary movements in the 6-ohda - lesioned rat model of pd . with respect to ad , amyloid- protein
was reported to promote neurodegeneration by inducing l - vscc expression and suppressing vdr expression ; subsequent treatment with vitamin d protected neurons by preventing cytotoxicity and apoptosis , probably by downregulating l - vscc and upregulating vdr .
calcitriol decreased l - vscc activity in aged rats and in neuronal vulnerability with particular impact on reducing age - related changes associated with ca dysregulation [ 118 , 119 ] .
treatment with 24r , 25 dihydroxyvitamin d3 also reduced l - vscc activity in vascular smooth muscle in rats .
ngf is a small secreted protein that is important for the growth , maintenance , and survival of certain target neurons .
ngf has been implicated in maintaining and regulating the septohippocampal pathway , which is involved in learning and memory [ 121123 ] .
ngf concentrations are decreased in the sn of the pd and in a rat model of pd [ 69 , 126 ] .
ngf levels showed greater reductions in early states of the disease compared with advanced stages , implying that decreased ngf may be involved in the pathogenesis of pd .
ngf is reported to protect dopamine neurotoxicity induced by mptp , rotenone , and 6-ohda via different pathways [ 127129 ] .
the chronic infusion of ngf into the rat striatum resulted in cholinergic hyperinnervation and reduced spontaneous activity of striatal neurons . moreover
, ngf increases survival of dopaminergic grafts , rescues nigral dopaminergic neurons , and restores motor dysfunction in a rat model of pd [ 131 , 132 ] .
in addition , the brains of newborn rats from vitamin d - deficient dams showed reduced expression of ngf . in vitro
, calcitriol regulated the expression of the vdr gene and stimulated the expression of the ngf gene in schwann cells .
in mouse fibroblasts , calcitriol and vitamin d analogs are reported to enhance ngf induction by increasing ap-1 binding activity to the ngf promoter [ 134 , 135 ] .
mmps are proteolytic enzymes responsible for extracellular matrix ( ecm ) remodeling and the regulation of leukocyte migration through the ecm , which is an important step for inflammatory processes .
application of dopaminergic neurotoxins to two human neuroblastoma cell lines downregulates the transcription and translation of tissue inhibitor of metalloproteinase- ( timp- ) 2 effectively enhancing mmp activity .
exendin-4 , which is an analogue of glucagon - like peptide 1 ( glp-1 ) , significantly attenuates the loss of sn neurons and the striatal dopaminergic fibers in the mptp - induced pd model , and inhibits the expression of mmp-3 .
conversely , the vdr taqi polymorphism is associated with decreased production of timp-1 , a natural inhibitor of mmp-9 .
calcitriol downregulates mmp-9 levels in keratinocytes and may attenuate deleterious effects due to excessive tnf--induced proteolytic activity associated with cutaneous inflammation .
in addition , a vitamin d analogue was reported to reduce the expression of mmp-2 , mmp-9 , vegf , and parathyroid hormone - related protein in lewis lung carcinoma cells .
these findings suggested that vitamin d plays a role in modulating mmp activation in pd .
pge2 is a key product of cox-2 and is increased in the sn of patients with pd and mptp - induced pd in an animal model [ 145 , 146 ] .
overexpression of cox-2 is reported in pd and an mptp - animal model [ 148 , 149 ] .
similarly , regular use of cox-2 inhibiting nonsteroidal anti - inflammatory drugs ( nsaids ) , such as ibuprofen , has been associated with a decreased incidence of pd .
calcitriol , which reportedly regulates the expression of several key genes involved in pg pathways , decreases pg synthesis .
calcitriol and its analogues have also been shown to inhibit selectively the activity of cox-2 .
these findings suggested that vitamin d has a role in anti - inflammatory processes in pd .
analyses of postmortembrains from pd reveal evidence of increased lipid peroxidation in pd sn [ 155 , 156 ] .
a selective superoxide dismutase ( sod ) is also increased in the sn of pd patients .
calcitriol administration has been reported to exert a receptor - mediated effect on the secretion of hydrogen peroxide by human monocytes . in vitro
, monocytes gradually lose their ability to produce superoxide when stimulated ; the addition of calcitriol , lipopolysaccharide , or lipoteichoic acid ( lta ) restored the ability of stimulated monocytes to produce superoxide and increases the oxidative capacity compared with unstimulated monocytes .
calcitriol can also protect nonmalignant prostate cells from oxidative stress - induced cell death by preventing ros - induced cellular injuries .
vitamin d metabolites and analogues were reported to induce lipoxygenase mrna expression , lipoxygenase activity , and ros production in a human bone cell line .
vitamin d can also reduce lipid peroxidation and induce sod activity in the rat hepatic antioxidant system .
nos is an enzyme involved in the synthesis of nitric oxide ( no ) , which has also been implicated in pd . in postmortem brains of pd
, high levels of nos expression were found in the nigrostriatal region and basal ganglia .
a significant increase in the nitrite content was reported in polymorphonuclear leukocytes of pd patients .
inducible and neuronal no are increased in both 6-ohda and mptp animal models [ 165 , 166 ] .
moreover , studies with nos inhibitors and nos knock - out animals have also confirmed the role of nos in neurodegeneration [ 167 , 168 ] .
reduced and oxidized glutathione ( gsh ) were demonstrated in the sn of patients with pd .
conversely , the activation of 1-hydroxylase in macrophages increases in 1,25ohd , which inhibits inducible nos ( inos ) expression and reduces no production by lipopolysaccharide- ( lps- ) stimulated macrophages .
thus , calcitriol production by macrophages may provide protection against oxidative injuries caused by the no burst .
calcitriol is known to inhibit lps - induced immune activation in human endothelial cells . in experimental allergic encephalomyelitis
astrocytes play a pivotal role in cns detoxification pathways where glutathione ( gsh ) is involved in the elimination of oxygen and nitrogen reactive species , such as nitric oxide .
calcitriol affects this pathway by enhancing intracellular gsh pools and significantly reduces nitrite production induced by lps .
vitamin d may be beneficial in pd patients , as one patient showed improved rigidity and akinesia and was able to decrease their levodopa dosage after vitamin d therapy .
genetic studies have provided opportunities to determine what proteins may link vitamin d to pd pathology .
vitamin d can also act through a number of nongenomic mechanisms , including effects on protein expression , oxidative stress , inflammation , and cellular metabolism . among the many forms of vitamin d ,
calcitriol ( 1,25-dihydroxyvitamin d3 ) is an attractive therapeutic candidate , because it is a particularly active metabolite , and its receptor is expressed in the cns . | parkinson 's disease ( pd ) is the second most common form of neurodegeneration in the elderly population .
clinically , it is characterized by tremor , rigidity , slowness of movement , and postural imbalance .
a significant association between low serum vitamin d and pd has been demonstrated , suggesting that elevated vitamin d levels might provide protection against pd .
genetic studies have helped identify a number of proteins linking vitamin d to pd pathology , including the major histocompatibility complex ( mhc ) class ii , the vitamin d receptor ( vdr ) , cytochrome p450 2d6 ( cyp2d6 ) , chromosome 22 , the renin - angiotensin system ( ras ) , heme oxygenase-1 ( ho-1 ) , poly(adp - ribose ) polymerase-1 gene ( parp-1 ) , neurotrophic factor ( ntf ) , and sp1 transcription factor .
vitamin d has also been implicated in pd through its effects on l - type voltage - sensitive calcium channels ( l - vscc ) , nerve growth factor ( ngf ) , matrix metalloproteinases ( mmps ) , prostaglandins ( pgs ) and cyclooxygenase-2 ( cox-2 ) , reactive oxygen species ( ros ) , and nitric oxide synthase ( nos ) .
a growing body of evidence suggests that vitamin d supplementation may be beneficial for pd patients . among the different forms of vitamin d ,
calcitriol ( 1,25-dihydroxyvitamin d3 ) is best indicated for pd , because it is a highly active vitamin d3 metabolite with an appropriate receptor in the central nervous system ( cns ) . |
this automatic system is controlled by reflex mechanisms in the limbic system of the brain and brainstem .
dysfunction may also be engendered by faulty neurotransmission in the peripheral distribution of autonomic nerves .
the sympathetic , or thoraco - lumbar outflow system , activates physical and mental action and its best known reflex is the fight - or - flight .
the sympathetic system uses acetyl choline at the proximal ganglion and nerepinepthrine at the distal terminal ganglion .
the parasympathetic , or cranio - sacral outflow , opposes the actions of the sympathetic system .
increased tone in one system is modulated by decreased tone in the other , an essential balance that results in a continuous adaptation to environment .
the concept of homeostasis is more aptly seen as homeodynamics , a continuous reaction between environment and the adaptive status of the organism .
symptoms of dysautonomia are caused by inefficient , abnormal or unbalanced efferent signals distributed via the two systems .
panic attacks. increased parasympathetic tone may result , for example , in bradycardia , or increased intestinal peristalsis .
stress is defined in the ensuing text as the sensory input to the limbic system computer .
sir roger bannister edited perhaps the most complete discussion of autonomic nervous system disease ( 1 ) . in the various syndromes described in this book
. a well - known form of dysautonomia , albeit rare , is that originally described by riley and associates and further described more completely by riley ( 2 ) , a genetically determined disease affecting ashkenazic jews .
riley and moore ( 3 ) reported children , however , with a puzzling appearance of dysautonomia that did not completely conform to the symptomatology and physical signs considered to be necessary for this diagnosis .
the medical literature is replete with isolated reports of dysautonomia , associated with various disease entities . in none of these publications
is the etiology of the dysautonomia made clear and it is always left as an isolated observation .
evidence is presented that loss of oxidative efficiency , particularly affecting the limbic brain and brainstem , is responsible for both the dysautonomia and possibly its associated organic disease .
the underlying etiology can be genetic , epigenetic or due to imbalance between caloric and non - caloric nutrients as seen in beriberi , the prototype of functional dysautonomia .
reports of dysautonomia appeared throughout the 20th century in literature that is now seldom studied .
coghlan et al . ( 4 ) noted the associations of dysautonomia with mitral valve prolapse and even suggested the possibility that this now common lesion might be a disorder of the patient 's computer ( 5 ) .
mitral valve prolapse has been recognized in association with scoliosis ( 6 ) , a phenomenon that occurs in familial dysautonomia ( 2 ) .
adie was an early clinical investigator and many of the patients he described had asymmetry as part of the expression of the dysautonomia ( 8) .
orthostatic hypotension , long known as a feature of dysautonomia , has been associated with amyloidosis ( 9 ) , the shy drager syndrome ( 10 ) and wernicke 's disease ( 11 ) .
at least three publications reported forms of dysautonomia , one with recovery for which no explanation was offered ( 1214 ) .
rubin studied pupillary re - activity in psychotic adult patients and autistic children and found evidence of dysautonomia ( 15,16 ) .
abnormalities in circadian patterns have been published as implications for myocardial ischemia , a common cause of contemporary disease ( 17 ) .
( 18 ) stated in 1978 that there was a great awareness of the role of behavioral responses in human ischemic heart disease .
they reported electron microscopic evidence of early atherogenic changes in the aorta and coronary arteries in normally fed rats receiving electrical stimulation in the lateral hypothalamus .
dysautonomia was suggested as the underlying pathophysiology in four apparently healthy young adults with vague chest symptoms during the day , two of whom had infrequent nocturnal ambulatory syncope ( 19 ) . both prolongation ( 20 ) and shortening ( 21 ) of the electrocardiac qt interval have been associated with autonomic dysfunction .
dysautonomia - related symptoms have been recorded in some cases of cyclic vomiting , a predominantly childhood condition ( 22 ) .
the authors suggested that an increased comorbidity with a distinct list of medical conditions in this syndrome may relate to a higher degree of mitochondrial dysfunction .
a french publication presented a case report of a woman with orthostatic hypotension , syncope and other signs of sympathetic dysfunction ( 23 ) .
the authors noted that chronic autonomic disorders may complicate a wide range of conditions that can be divided into secondary , due to specific diseases and primary , in which no cause has been determined .
hypervagal responses have been described as the underlying mechanism of dysautonomia rhinitis , an interesting association with the autonomic nervous system ( 24 ) .
obstructive sleep apnea has been associated with abnormalities in stress tests of cardiovascular response in the autonomic nervous system ( 25 ) .
thus , obstructive sleep apnea appears to operate by its secondary effect on the mechanisms involving automatic respiration .
the obvious conclusion to be drawn is that the low oxygen saturation affected central control of the autonomic nervous system .
autonomic dysfunction in sleep apnea has also been associated with impaired glucose regulation ( 26 ) .
the authors concluded that their syncope patients had dysautonomia that appeared as both a sympathetic and parasympathetic hypofunction ( 27 ) .
neuralgiform headaches with conjunctival injection and tearing ( sunct ) and short - lasting unilateral neuralgiform headaches with cranial autonomic features ( suna ) were studied .
a percentage of both these forms of headache were triggered by cutaneous tactile stimuli ( 28 ) , suggesting an exaggerated or hyperactive central response .
the question raised here is whether there is a common etiology to tie so many reports of dysautonomia together .
it is suggested that biochemical changes affect either the autonomic nervous system itself or its central control , leading to inefficient oxidative metabolism similar to the effects of hypoxia .
gibson and zhang ( 29 ) reported oxidative stress in chronic brain disease involving disturbance of thiamin homeostasis .
kern and jones ( 30 ) reviewed the evidence for oxidative stress in autism and butterworth ( 31 ) compared the etiology of autism with that in wernicke 's encephalopathy ( wks ) .
both diseases involve loss of purkinje cells and wks has been reported in children ( 32 ) .
purkinje cells are selectively vulnerable to oxidative insufficiency and the nature of tissue damage in thiamin deficiency resembles that observed following anoxic / ischemic insults ( 30,31 ) .
measurement of high energy phosphates in brains of symptomatic pyrithiamine - treated rats revealed decreases of atp and phosphocreatine in the brainstems of affected animals ( 33 ) .
when the patient died , autopsy showed the typical pathology of wks , a brain lesion well known to be related to thiamin deficiency .
this was in spite of the fact that 24 mg of thiamin a day was provided in the intravenous fluid .
it has to be concluded that the mechanism involved an imbalance between the concentration of administered glucose and the required redox potential .
this complication might also be explained by a failure to phosphorylate thiamin pyrophosphate ( tpp ) to synthesize thiamin triphosphate ( ttp ) ( 35 ) .
although there is still insufficient knowledge about the role of ttp , it is known to be extremely important in energy metabolism in brain ( 3640 ) .
it has long been known that the pathology associated with this is functional imbalance of the autonomic nervous system in the early stages of the disease and its ultimate destruction in the later stages ( 41 ) .
indeed , the neurological symptoms and signs recorded many years ago in japan were so diverse ( table 1 ) that they should be noted in our modern era where simple carbohydrates are consumed in enormous excess , particularly in western cultures .
table 1.neurological symptoms and signs of beriberi ( 41)general nutritional state appears to be good : e.g. seen in robust workersedemadiencephalic dysfunctional control of autonomic nervous systemcardiac palpitation on mental or physical exertionincreased cardiac outputekg changes ; abnormal t waves ; prolonged qt intervaldicrotic pulselow diastolic pressure , may reach zero ; normal or high systolic blood pressureaudible femoral pulse , particularly in childrenlow arterial , high venous oxygen concentrationlabile vasomotor function ; abnormal response to adrenalin and atropinevagotonia / sympathicotoniaincreased basal metabolic ratesequential sensory disturbances , including parasthesiaeproprioceptive perception decreased after superficial sensory changes neurological symptoms and signs of beriberi ( 41 ) there is now general acceptance of the role of thiamin in the etiology of beriberi .
but the disease must be understood in its obvious association with the biochemistry of glucose in energy metabolism .
one of the important observations made in studying patients with beriberi was that arterial oxygen saturation is relatively low in the disease when venous oxygen concentration is relatively high ( 41 , table 1 ) , the same phenomenon as was reported in sleep apnea ( 25 ) and also reported to be related to glucose dysregulation ( 26 ) .
it has long been known that increasing the ingestion of simple carbohydrate in the diet automatically increases thiamin requirements .
lonsdale and associates provided evidence that the enormous consumption of sugar in america represents high calorie malnutrition ( 4245 ) .
one of these publications ( 45 ) discussed the role of thiamin deficiency in lower brain dysfunction that could have serious effects in automatic control mechanisms of the autonomic nervous system .
this included a case report of a woman whose thiamin deficiency produced symptoms that were very suggestive of imitating high altitude sickness , caused in some people sensitive to the rarefied oxygen concentration .
oxygen - chemosensitive sites are distributed throughout the brain stem from the thalamus to the medulla and may form an oxygen - chemosensitive network ( 46 ) .
the recent scientific literature involving the autonomic nervous system is represented in relation to its biochemical etiology and the relation with nutrition .
the sympathetic nervous system plays an important role in the regulation of adipose tissue lipolysis .
elevated baseline and exercise - induced sympathetic nervous activity and exercise - induced lipolysis in adipose tissue were reported in anorexia nervosa ( 48 ) .
whether this is the primary etiology or secondary to the ensuing malnutrition is not clear .
evidence was provided that sympathetic nervous activity in vitamin e - deficient rats was greater than in control animals ( 51 ) .
chronic exposure to moderate and severe hypoxia increases the activity of the sympathetic nervous system and adrenal medulla in rats ( 52 ) and thiamin deficiency induces an early functionally significant central muscarinic cholinergic lesion in rat studies ( 53 ) .
another rat study suggested that the sympathetic nervous system in spleen and heart were stimulated by vitamin a deficiency ( 54 ) .
magnesium deficiency has been shown to play a role in the pathogenesis of mitral valve prolapse ( 55 ) , already mentioned in this review as being associated with dysautonomia ( 4,5 ) .
autonomic system excitability ( 56 ) and autonomic circulatory regulation in rats ( 57 ) have been associated with magnesium deficiency .
the biological basis of antisocial and aggressive behavior in children was reviewed with a focus on low autonomic functioning , pre - frontal deficits and early health factors that include malnutrition in pregnancy ( 58 ) . in heavy drinkers with evidence of autonomic neuropathy revealed by various tests
, erectile dysfunction appeared to be the sole symptom , involving loss of parasympathetic function .
the authors stated that none of the studied patients showed signs of caloric / protein malnutrition but vitamin / mineral deficiency was not recorded ( 59 ) .
sweating , tachycardia , dermographia , both wide and narrow unstable pulse pressure , attention deficit and other dysautonomic symptoms in children have been published ( 62 ) .
these symptoms have been shown to respond to dietary instruction , with particular reference to removal of sugar in all its commercial forms together with dietary supplements that always include thiamin and magnesium .
simon ( 63 ) suggested a metabolic similarity in wks and autism . it was pointed out that thiamin deficiency , by disabling the aerobic pathway for glucose metabolism , is equivalent to oxygen deprivation .
an acute episode of asphyxia brought about by different means , affects the same brainstem nuclei .
these investigators reported a skewed representation of male subjects , an observation that is well known in this disease .
it has been suggested that infants succumbing to this death require the combination of genetic predisposition , one or more stress factors and defective oxidative metabolism that might be related to nutrient deficiency ( 67 ) .
these observations are similar to the combination of factors reported in autism ( 30 ) .
thiamin supplementation has been reported to be beneficial in autism ( 68 ) , in sids ( 6973 ) and thiamin triphosphate deficiency was reported in the phrenic nerve of sids victims ( 74).clinical improvement in autistic spectrum disorders has been reported from treatment with secretin ( 75 ) .
the investigators suggested that the action of secretin was through brain stimulation since there are known receptors for this hormone in the hippocampus .
a clinical study reported varying degrees of improvement in behavior and/or bowel function using a single injection of secretin ( 76 ) .
one 7-year - old boy , included in this study , had great improvement in behavior noted by his parents .
they also reported an observation that clearly suggested improved autonomic function . before the single injection of the hormone , this child had pupils that were noted to be fixed and dilated , not even responding to sunlight . immediately following the injection his pupils began to respond normally to light .
there is no attempt to suggest an anatomical configuration in separating the cognitive from the limbic systems .
the limbic system is presented as a computer that enables continuous energy - dependent adaptation to environmental stress . a revised model for disease .
the limbic system is presented as a computer that enables continuous energy - dependent adaptation to environmental stress .
genetics , represented by the first circle , always needs to be factored in , but in most cases the physician has no knowledge of his patient 's genome . even a family history does not provide clues since the underlying biochemical mechanism of a given inherited disease is often unknown .
there are obvious exceptions such as phenylketonuria and other inborn errors of metabolism where specialized dietary therapy is the only recourse , but even those have variants .
it is suggested that the genome contains genetic traits that may constitute unknown weaknesses such as enzymatic polymorphisms .
genetic predisposition is usually an unknown that can not be blamed for the onset of disease on its own unless it is a flagrant mendelian abnormality , leading on its own to loss of function .
the first reported case of thiamin - dependent pyruvic dehydrogenase deficiency ( 78 ) was a child whose episodes of cerebellar ataxia were initiated by infection , inoculation or head injury .
the functions of the genome are now known to be influenced by environmental factors , diet and life style .
the second interlocking circle is labeled stress the inevitable result of being alive in a hostile environment .
it can obviously be divided into its mental input , often thought of as the only form of stress encountered by humans and its physical input , such as injury , infection or inoculation .
adaptive mechanisms are automatically put in effect through the autonomic nervous and endocrine systems , controlled by the limbic brain .
the cognitive brain is aware but may fail to suppress the limbic action , a phenomenon that gives rise to lack of self control .
the best - known reflex is fight - or - flight and so - called panic attacks are obviously fragmented examples of this reflex , extremely common today in my experience .
computer is equipped with a host of survival reflexes involving thirst , hunger and sexual drive .
each is designed for survival of the species ( e.g. sexual drive ) or the individual ( thirst , hunger ) . the stress , if not in itself overwhelming such as severe trauma , is monitored and data processed by the limbic computer and the necessary adaptive machinery is put into action .
such obvious ones are how the brain adapts to mental insult emotionally and how it initiates adaptation to physical factors such as environmental temperature , or change in barometric pressure .
circadian rhythm adapts us to the day / night cycle and seasonal adaptive disease is an obvious example of failed adaptation .
if cellular energy is deficient the necessary adaptive response is inappropriate . as in beriberi , however , these reflex reactions , mediated through the hypothalamic / endocrine / autonomic axis are increased in the early stages of marginal high calorie malnutrition .
observation of many patients in our clinic has led to the conclusion that high calorie malnutrition results in hypersensitivity of the limbic system .
the hypothalamic / endocrine / autonomic axis and limbic system emotional reactions become activated much too easily by virtually any form of stress input .
when the empty calories are removed from the diet , particularly simple carbohydrates , the symptoms disappear and the adaptive reflexes return to normal . before treatment ,
this has strongly suggested that this form of malnutrition might be responsible for some of the otherwise inexplicable juvenile crime so common today ( 80,81 ) .
mild insults that would normally be either ignored or initiate normal anger response become exaggerated in the processing of hostile information .
if these nutrients are replaced with empty calories we incur risk of inefficient metabolism and this will affect the most oxygen demanding tissues .
it is , therefore , not surprising that beriberi is an example of a relatively high calorie nutritional deficiency disease that causes failure is the most oxygen demanding organs , brain , nervous system and heart .
thiamin stands at the gate of the citric acid cycle , a key factor is aerobic metabolism , but this vitamin is only one of the principles necessary .
its place in that function , however , can be used as a model for what happens when the result in inefficient energy synthesis .
evidence offered in this manuscript indicates that a victim of high caloric malnutrition becomes poorly adapted to the constant daily input of environmental stressors , resulting in autonomic / endocrine dysregulation .
a very old experiment in human volunteers led to multi - symptom functional changes that ensued when the subjects were exposed to a thiamin - deficient diet ( 82 ) .
it is virtually certain that the present existing model for disease would label the symptomatology as nervous , neurotic or psychosomatic. in the later stages , the result of increasingly inefficient oxidative metabolism , the normal adaptive signaling processes break down and degenerative organ disease may well be a result . as the immune response breaks down
microorganisms are stressors and normally initiate defense mechanisms mediated by the computer. the gradual decay in metabolic function may lead to the variable effects associated with disease , aging and eventual death .
evidence has been produced to indicate that various forms of mild to moderate vitamin deficiencies result in functional changes in the autonomic nervous system .
this is clearly shown by a study of the clinical effects seen in beriberi ( 41 ) .
it is hypothesized that the predictable loss of efficiency in oxidative metabolism is the key to understanding the association of dysautonomia with many different diseases .
it is suggested that a gradual increase in oxidative dysfunction also gives rise to changes in organs , causing subsequent organic disease in some cases .
the ample evidence of dysautonomia with various nutrient deficiencies , referenced in this article , suggests strongly that the state of redox potential in the high oxygen demand automatic centers of the brainstem and limbic system is impaired .
this would explain why dysautonomia is reported in so many isolated case reports where the published association appears to be little more than an interesting observation .
evidence is presented here that one method of inducing this is by high caloric malnutrition involving excessive ingestion of empty calories , a potent factor in functional disease that is being overlooked , particularly in children . when diet histories are considered carefully
it is sometimes obvious that there is more attention to the content of meals rather than the consumption of ad lib snacks between meals . in one boy
seen in our clinic the consumption of cola amounted to about 2 gallons a week .
often children like this are being given vitamin supplements under the false impression that this would prevent any consideration of nutritional deficiency .
evidence has been presented to indicate that a genetically or epigenetically determined weakness in the genome is responsible for intermittent disease in some inborn errors of metabolism , creating susceptibility to environmental stress factors , such as infection .
polymorphisms , common in the population , appear to provide a genetic risk to many children in the increasingly severe industrial pollution that we face in the modern world ( 30 ) .
chronic fatigue syndrome , considered to be related to mitochondrial inefficiency , sids and autistic spectrum disorder ( asd ) ( 83 ) are presented here as typical examples of genetic or epigenetic risk , the stress factors being one or more of several possibilities including heavy metal toxicity , antibiotic abuse , infection with micro - organisms , industrial and possibly electromagnetic pollution and various forms of mental pressures imposed by civilization . to meet the imposed stress factor
requires an adaptive response that requires appropriate nutrition and lifestyle to provide the necessary energy .
various successful therapeutic measures such as acupuncture suggest that electrical or electromagnetic energy is used for intracellular communication . whether this is generated from biochemical action or not is unknown at present .
an individual unable to meet the required energy demand might be seen as maladapted to the environment .
the tongue is a sensory organ that provides taste input to the receptor cells in brain .
since this consists of stimuli from sweet , sour , bitter , salt , astringent and metallic , all organic foods provide permutations and combinations of sensory stimulation that the brain interprets as flavor .
thus , the sensual pleasure derived from sugar ( or any other sweetener ) alone is suggested as an explanation of its addictive nature .
many polysymptomatic patients are similarly salt cravers . removing them completely results in symptomatic improvement in many of the patients treated in our clinic .
it is suggested that high caloric malnutrition , particularly in the form of simple carbohydrates , is a common cause of defective autonomic control mechanisms in the lower brain that can be likened to the early stages of classic beriberi . | dysautonomia refers to a disease where the autonomic nervous system is dysfunctional .
this may be a central control mechanism , as in genetically determined familial dysautonomia ( riley - day syndrome ) , or peripherally in the distribution of the sympathetic and parasympathetic systems .
there are multiple reports of a number of different diseases associated with dysautonomia .
the etiology of this association has never been explained .
there are also multiple publications on dysautonomia associated with specific non - caloric nutritional deficiencies .
beriberi is the prototype of autonomic dysfunction .
it is the best known nutritional deficiency disease caused by an imbalance between ingested calories and the vitamins required for their oxidation , particularly thiamin .
long thought to be abolished in modern medical thinking , there are occasional isolated reports of the full - blown disease in developed western cultures.apart from genetically and epigenetically determined disease , evidence is presented that marginal high calorie malnutrition , particularly with reference to simple carbohydrates , is responsible for widespread dysautonomia .
the brain and heart are the organs that have a fast rate of oxidative metabolism and are affected early by any mechanism that reduces oxidative efficiency .
it is hypothesized that this results in a chaotic state of the hypothalamic / autonomic / endocrine axis . due to the lack of adequate automatic controls ,
this may be responsible in some cases for breakdown of organ systems through long - standing energy deficiency , thus leading eventually to organic disease . |
our comprehensive base case costing model is presented in table 1 , separated into perspectives from australian , canadian , and the uk health - care systems .
total costs for each modality were relatively consistent in year 1 . from year 2 onward ,
specifically , the model predicts that , over time and depending on location , conventional home dialysis would save payers between $ 7612 and $ 12,403 over the first year of conventional in - center hemodialysis .
the model predicts that frequent home hemodialysis , with its increased costs of consumables and materials , would cost uk payers $ 4408 in subsequent years .
however , frequent home hemodialysis would save canadian payers $ 3411 and australian payers $ 4036 in subsequent years compared with first year in - center hemodialysis costs . in - center
hemodialysis costs are stable over time as the cost to provide hemodialysis in a center is conservatively assumed to stay relatively constant year after year .
renal medication , human resources , hospitalizations , consumables , and facility ( overhead ) costs are the primary cost drivers for in - center hemodialysis .
conventional home hemodialysis and frequent home hemodialysis costs in year 1 are greater than those in subsequent years , as costs of hemodialysis reduce in subsequent years after capital investments and training have been paid for . these conventional home and frequent hemodialysis costs are driven by renal medication , capital investment , patient training ( primarily training nurse costs ) , machines , consumables ( more for frequent home hemodialysis ) , home preparation , training , and hospitalization costs . to illustrate the impact of component costs , figure 1
the sensitivity analysis demonstrated that changes to the major drivers of total cost , such as staffing costs and facility costs , can substantially impact the overall costs .
for example , when evaluating the range of total costs while adjusting the total allied health - care costs to 25% of the original cost input , total costs for conventional home hemodialysis in canada goes from being less than that for in - center hemodialysis to more than that in year 1 . in comparison ,
when increasing the original cost input of total allied health - care costs by 25% in the united kingdom in year 1 , total costs for in - center hemodialysis move from being less than to more than total costs for conventional home hemodialysis . across all component costs
, there were four instances in year 1 ( 7.5% ) and one instance in subsequent years ( 2.4% ) where adjusting the component cost plus or minus 25% changed the total costs of a hemodialysis modality from being more than to less than another modality .
the sensitivity analysis demonstrated that changes to the major drivers of total cost , such as staffing costs and facility costs , can substantially impact the overall costs .
for example , when evaluating the range of total costs while adjusting the total allied health - care costs to 25% of the original cost input , total costs for conventional home hemodialysis in canada goes from being less than that for in - center hemodialysis to more than that in year 1 . in comparison ,
when increasing the original cost input of total allied health - care costs by 25% in the united kingdom in year 1 , total costs for in - center hemodialysis move from being less than to more than total costs for conventional home hemodialysis . across all component costs
, there were four instances in year 1 ( 7.5% ) and one instance in subsequent years ( 2.4% ) where adjusting the component cost plus or minus 25% changed the total costs of a hemodialysis modality from being more than to less than another modality .
derived from data in published cost studies , we have generated a transparent , logical costing model that includes both start - up and operating costs for conventional home hemodialysis and frequent home hemodialysis as compared with in - center hemodialysis .
as anticipated , the results of our model are consistent with the findings of most costing studies to date , in that conventional home hemodialysis and frequent home hemodialysis are similar in cost to in - center hemodialysis in the first year ( driven primarily by training costs ) but can be less costly than in - center hemodialysis from the second year onward , depending on the frequency of dialysis . the results of the model show that year 1 costs are largely a result of higher start - up costs , but lower human resource costs , for home hemodialysis submodalities as compared with in - center hemodialysis .
in year 2 and beyond , conventional home hemodialysis is less expensive than in - center hemodialysis .
specifically , the model predicts that , over time and depending on location , conventional home dialysis would save payers between $ 7612 and $ 12,403 over the first year of conventional in - center hemodialysis .
the model shows that frequent home hemodialysis , with its increased costs of consumables and materials , would cost uk payers $ 4,408 in subsequent years .
however , frequent home hemodialysis would save canadian payers $ 3411 and australian payers $ 4036 in subsequent years compared with the first year in - center hemodialysis costs .
decreased staffing costs coupled with lower facility overhead and medication costs drove this cost differential .
that is , there are initial training costs for home hemodialysis patients ( and their family members ) .
once trained , there are minimal human resource costs associated with home hemodialysis modalities , whereas the human resource costs for in - center hemodialysis stay consistent over time as payers are responsible for the salaries of staff who provide dialysis .
a review of the published cost studies reveals that all three forms of home hemodialysis ( conventional , nocturnal , and short daily home hemodialysis ) may have economic advantages over in - center hemodialysis .
these studies also demonstrate the clinical advantages of more frequent intensive hemodialysis relative to less frequent hemodialysis while being cost neutral or cost saving to the payer . the most persuasive evidence ( based upon study size , quality of study , and number of studies with consistent results )
finds that costs for home hemodialysis are substantially lower than costs for in - center hemodialysis . in addition , costs per quality - adjusted life year appear to be better for conventional home hemodialysis compared with in - center hemodialysis .
no study to date ( to our knowledge ) has attempted to summarize the findings of these studies to come to a comprehensive summary of the component cost inputs of conventional home hemodialysis or frequent home hemodialysis when compared with in - center hemodialysis .
the number of patients on home hemodialysis has grown significantly over the past several years globally .
canada and the united kingdom have developed similar , although nonidentical , methods for reimbursing dialysis services .
canada 's single - payer universal health - care system funds providers , hospitals , or provincial programs to provide all dialysis care .
care is often provided within a case rate payment : cdn $ 55,466 ( us $ 45,094 ) per patient with end - stage renal disease .
the uk 's national health service funds dialysis care through a special commission on a countrywide basis through the use of health - related group payments for care .
the health - related group for hemodialysis , lc01a , had an average payment per dialysis session of 153 for in - center hemodialysis and 83 for home hemodialysis in 2007 , which translates to a yearly payment of 23,443 ( us$37,393 ) and 18,270 ( us$29,142 ) per year , respectively .
the six australian states are funded to provide dialysis through a mix of capitation and case payments .
one state ( victoria ) has added incentives of aud$10,000/patient / year paid to renal services for each nocturnal home hemodialysis patient who is home installed , with out - of - pocket expenses for water , power , and cleaning reimbursed at aud$1,200/year for each home hemodialysis patient .
given these varying payment systems for hemodialysis , payers may have difficulty synthesizing the published literature to determine what information is relevant to their context .
our costing model was developed to assist payers in understanding the component cost drivers of home versus in - center hemodialysis in more detail .
decision makers representing different localities or with costs not consistent with modeled data should adjust component costs accordingly if attempting to use the model to estimate costs in a specific local setting .
this information can be used to inform coverage policy development , especially in reference to developing payment systems that encourage home hemodialysis options ( conventional , nocturnal , and short daily home hemodialysis ) .
our costing model has several limitations . as mentioned previously , our review of the existing costing literature yielded inconsistent evidence related to costs of conventional home , frequent home , and in - center hemodialysis between and within australia , canada , and the united kingdom . despite this
, we feel that our model is transparent enough to allow for specific costs to be varied easily by decision makers in tailoring our analysis to almost any payer model . because no one study captured all required cost inputs , the model used inputs from a variety of studies . as a result ,
heterogeneity exists within the methods used by the referenced cost studies . our use of sensitivity analysis attempts to address this . costing data for home hemodialysis should be augmented by randomized control trial data .
the national institutes of health ( nih)-sponsored frequent hemodialysis network trial has recently published results on the clinical outcomes associated with more frequent in - center hemodialysis , although currently published data do not yet include a cost analysis .
in addition , cost - effectiveness analysis could be used to capture the clinical and cost advantages of home hemodialysis modalities ( conventional , nocturnal , and short daily home hemodialysis ) compared with in - center hemodialysis .
additional research and modeling in this area would help to systematically evaluate both clinical and cost variables in a variety of settings .
the costing model presented here uses a hybrid of existing costing data and modeled inputs for key cost drivers across three hemodialysis modalities in four countries with heterogeneous payer models .
it can serve as a robust tool for payers and other decision makers to apply key cost drivers to make related decisions .
all home hemodialysis modalities have limitations and may not be the optimal solution for all patients .
improved access to dialysis delivery systems , with simpler operating procedures and portability , will allow more patients to undertake this modality .
for those patients likely to receive kidney transplant within 1 year of dialysis , home hemodialysis likely does not represent an optimal approach , given the high start - up , home preparation , and training costs .
however , the literature does reveal a large segment of dialysis patients for whom frequent home hemodialysis , via nocturnal home hemodialysis or short daily home hemodialysis , would be a beneficial approach .
although the costs described within the model inform reimbursement decision making , they must be contextualized within the broader clinical literature .
payers can take an active role in using reimbursement policy to encourage clinicians to use the most effective home hemodialysis approaches .
this model provides a tool for payers to make a cost determination for their patient population ; given the model 's findings of two of the three locations incurring lower total costs after the first year of home hemodialysis , this could be an informative exercise for payers while potentially improving the quality of lives for patients .
three hemodialysis modalities were selected for cost modeling based on the number and quality of cost studies available .
these are as follows : in - center hemodialysis , conventional home hemodialysis , and more frequent home hemodialysis .
frequent home hemodialysis is inclusive of nocturnal home hemodialysis ( dialysis performed for 610 h per night for up to 7 nights per week ) and short daily home hemodialysis ( dialysis performed for 2 to 3 h per day for up to 7 days per week ) , which is based on the assumption that short daily home hemodialysis costs are similar to nocturnal home hemodialysis costs , although the authors recognize that small differences in resource utilization between the two modalities may exist .
short daily home hemodialysis costs were not specifically included in the model because of a lack of published , comprehensive cost data specific to that submodality available at the time of this analysis .
the current costing studies take different perspectives and were conducted under a variety of funding regimes . to provide a holistic view of costs across multiple countries , we constructed a standardized cost model from the payer / funder perspective using inputs from published costing studies .
the purpose of the model is to provide payers and decision makers with a comprehensive , robust tool to accurately and transparently capture the cost of home hemodialysis services .
this costing tool will aid in setting informed , evidence - based reimbursement policies to expand access to home hemodialysis in general and to more intensive home hemodialysis specifically .
the cost model is a transparent spreadsheet that summarizes component costs for in - center hemodialysis , conventional home hemodialysis , and frequent home hemodialysis within each of the three countries ( australia , canada , and the united kingdom ) .
the three countries were selected for two reasons : first , over half of the available published cost data are related to them ; and second , they represent distinct reimbursement systems that are informative to other similar country reimbursement systems .
the united states was excluded from this analysis because of the unique funding system associated with medicare 's end - stage renal disease program and the limited us cost data specific to the different hemodialysis modalities .
the model was constructed from a payer 's perspective and therefore includes component costs that are routinely reimbursed by payers ( summarized in table 2 ) .
direct medical and well - documented direct nonmedical costs associated with dialysis ( e.g. , transportation to and from dialysis facilities ) have been included .
indirect nonmedical costs ( e.g. , lost time from work and unpaid assistance from family members ) are not included .
costs are considered in terms of start - up costs that would only be experienced in the first year of use , and then ongoing maintenance costs experienced in year 2 and beyond . as such
, variables are segmented by one - time costs directly related to hemodialysis ( e.g. , dialysis training costs ) and medical costs ( e.g. , consumable material costs , medications , professional reimbursement , and costs of emergency in - center hemodialysis runs ) experienced in the first year of dialysis .
once these items were established , we added further line items that would be considered standard ' in a comprehensively reimbursed home hemodialysis program ( e.g. , wetness detectors , scales , nursing , and allied health costs for clinic visits ) .
the model also provides a sum of all component costs per hemodialysis modality for year 1 and for subsequent years to derive a realistic cost picture that differentially accounts for start - up costs from ongoing costs experienced in subsequent years .
it is recognized that the majority of start - up costs would be experienced in the first several months of a patient 's dialysis care , but for the purposes of this model annual costs were used .
published costing studies and government - sponsored report data were used to derive annual best cost estimates for each component cost on a dialysis modality - specific basis .
where available , country - specific data were utilized . when country - specific data were not available , we used published data from the canadian setting .
these data were collected from the manitoba renal program at seven oaks general hospital in winnipeg , canada , where one of the authors practices . where data conflict existed ( e.g. , varying prices of dialysis machines ) , data inputs were selected from published studies prioritized by study , country perspective , and quality of the study .
( modifications were made based on the literature to reflect differences between the canadian , australian , and uk programs in which extrapolations were used . )
we conservatively used an estimate for year 1 ' costs for both year 1 ' costs and subsequent years ' costs to keep a proxy for hospitalization costs in the model without influencing any one modality 's results .
for each cost variable , costs were inflated to 2010 dollars using country - specific consumer price index and wage index from the year in the articles . to standardize costs across countries
when country - specific data were not available , costs were then converted to us dollars using appropriate currency exchange rates .
( although the use of purchasing power parity was considered , the authors ultimately chose this methodology as the costs are not intended to be compared across countries and the literature suggests that the cpi - based approach is an appropriate methodology for this type of analysis . )
sensitivity analyses were conducted on all variables using a standard range of plus or minus 25% .
the standard range was chosen because the source studies did not universally supply published sensitivity ranges .
each variable was initially analyzed to consider its impact on the base case cost analysis .
cost input values were then each varied plus or minus 25% to measure their impact on overall costs to determine the percentage of time that , across the plus or minus 25% range , the total costs of the hemodialysis modalities changed in relative rank order . | more intensive and/or frequent hemodialysis may provide clinical benefits to patients with end - stage renal disease ; however , these dialysis treatments are more convenient to the patients if provided in their homes .
here we created a standardized model , based on a systematic review of available costing literature , to determine the economic viability of providing hemodialysis in the home that arrays costs and common approaches for assessing direct medical and nonmedical costs .
our model was based on data from australia , canada , and the united kingdom .
the first year start - up costs for all hemodialysis modalities were higher than in subsequent years with modeled costs for conventional home hemodialysis lower than in - center hemodialysis in subsequent years . modeled costs for frequent home hemodialysis was higher than both in - center and conventional home hemodialysis in the united kingdom , but lower than in - center hemodialysis and higher than conventional home hemodialysis in australia and canada in subsequent years .
the higher costs of frequent compared to conventional home hemodialysis were because of higher consumable usage due to dialysis frequency .
thus , our findings reinforce the conclusions of previous studies showing that home - based conventional and more frequent hemodialysis may provide clinical benefit at reasonable costs . |
green fluorescent protein elongated hypocotyl 5 far - red light absorbing form of phytochrome red light absorbing form of phytochrome
it was also supported in part by the leaping research ( nrf-2015r1a2a1a05001636 ) and global research lab ( nrf-2012k1a1a2055546 ) programs provided by the national research foundation of korea and the next - generation biogreen 21 program ( plant molecular breeding center no . | abstractlight is a critical environmental cue for plant growth and development .
plants actively monitor surrounding environments by sensing changes in light wavelength and intensity .
therefore , plants have evolved a series of photoreceptors to perceive a broad wavelength range of light .
phytochrome photoreceptors sense red and far - red light , which serves as a major photomorphogenic signal in shoot growth and morphogenesis .
notably , plants also express phytochromes in the roots , obscuring whether and how they perceive light in the soil .
we have recently demonstrated that plants directly channel light to the roots through plant body to activate root phytochrome b ( phyb ) .
stem light facilitates the nuclear import of phyb in the roots , and the photoactivated phyb triggers the accumulation of the photomorphogenic regulator elongated hypocotyl 5 in modulating root growth and gravitropism .
optical experiments revealed that red to far - red light is efficiently transduced through plant body .
our findings provide physical and molecular evidence , supporting that photoreceptors expressed in the underground roots directly sense light .
we propose that the roots are not a passive organ but a central organ that actively monitors changes in the aboveground environment by perceiving light information from the shoots . |
pena shokeir phenotype / fetal akinesia deformation sequence is characterized by the lack of fetal movement , fetal intrauterine growth restriction , craniofacial anomalies , arthrogryposis , polyhydramnios , and pulmonary hypoplasia .
we report a case of pena shokeir phenotype occurring in one fetus of a monoamniotic pair .
a 43yearold patient , para 2 , gravida 3 , with two prior uneventful pregnancies , presented to our unit at 27 weeks of gestation .
twin a had decreased fetal movements , a thickened nuchal fold , hypertelorism , micrognathia , bilateral clubbed feet and clenched hands , and bilateral moderate hydrothoraces ( fig .
the patient was followed up weekly , but twin a developed ascites and the hydrothoraces worsened .
twin a weighed 2450 g and had an apgar score of 1/10 and 1/10 at 1 and 5 min , respectively .
she was markedly hydropic , which accounted for the increased weight , with no palmar or plantar creases .
she had a higharched palate , hypertelorism , abnormal lowset ears , micrognathia , ankylosis of large joints with hyperextension of upper and lower limbs , bilateral talipes equinovarus , and campylodactyly ( fig .
2 ) . resuscitation of twin a was difficult , and the baby demised in the first hour of life .
twin b was appropriately grown and weighed 1600 g and had an apgar score of 7/10 and 9/10 at 1 and 5 min , respectively .
she was admitted to neonatal icu as she was premature but demised 2 weeks later due to neonatal sepsis .
( a ) postdelivery image of twin a showing the facial profile ( hypertelorism , abnormal lowset ears , higharched palate ) .
( b ) postdelivery image of twin a showing hyperextended upper and lower limbs , bilateral clubbed feet , and campylodactyly .
intercostal drains were inserted in an attempt to resuscitate the baby in accordance with the mother 's wishes .
the postmortem of twin a revealed that there were thin cerebral and cerebellar cortices , cerebral cortical dysplasia , and diffuse skeletal muscle atrophy with fibrous displacement ( neurogenic atrophy ) .
the postmortem concluded that the baby had fetal akinesia deformation sequence ( pena shokeir syndrome ) most likely due to anoxic
ischemic etiology following cord entanglement , even though the cord entanglement was not identified at the time of delivery .
the pathogenesis of pena shokeir phenotype is attributable to familial muscle dystrophy or anoxic ischemic etiology .
however , the details of how this develops are still unclear . as there was no family history of pena shokeir phenotype in this patient and only one fetus was affected , the most likely etiology was thought to be anoxic ischemic .
the pathologist concluded that the absence of anterior motor horn cells in the spinal cord supported this .
a prospective observational study showed that cord entanglement is present in all monoamniotic twins when systematically evaluated by color doppler 1 . in most cases ,
, it can cause fetal death of one or both twins or discordant weights between twins . in our case
we find a hereditary mechanism unlikely as twin b and the patient 's previous two children were unaffected .
pena shokeir syndrome or fetal akinesia deformation sequence refers to early lethal neurogenic arthrogryposis and pulmonary hypoplasia .
the classic features include intrauterine growth restriction , craniofacial anomalies , limb contractures , pulmonary hypoplasia , short umbilical cord , short gut , and pregnancy complications such as polyhydramnios , abnormal uterine positioning , and decreased fetal movements .
craniofacial abnormalities related to decreased fetal movements include ocular hypertelorism , high bridge of the nose , underdeveloped tip of the nose , posteriorly angulated ears that appear lowset , short appearing neck with mild webbing , microretrognathia , higharched palate , and cleft palate 2 , 3 .
multiple ankylosis of elbows , knees , hips and ankles , rockerbottom feet , talipes equinovarus , and campylodactyly are present .
there is usually spinal cord involvement with loss or reduction in anterior motor horn cells .
twin a in our study demonstrated most of these phenotypic findings , and a diagnosis of pena shokeir syndrome was made .
the pathogenesis of pena shokeir phenotype may be attributed to familial muscle dystrophy or anoxic ischemic etiology . however , the details of how this develops are uncertain . six cases of pena
shokeir phenotype have been reported in monochorionic twins in the literature 4 , 5 , 6 , 7 .
five cases occurred in monochorionic diamniotic twin pregnancies 4 , 5 , 6 . in two of these cases ,
both twins were affected , and postmortem concluded that the etiology was myogenic as there were a normal number of anterior horn cells in the spinal cord 4 .
there is only one published case of a monoamniotic twin pregnancy with discordance in the pena
that case was similar to ours in that that fetus also had bilateral pleural effusions with a low lung / body weight ratio .
histology of that baby also showed a disuse atrophy pattern as well as loss of anterior horn cells .
this is a novel case as it is only the second reported in the literature of a discordant pena shokeir phenotype in a monoamniotic twin pregnancy .
| key clinical messagepena shokeir phenotype is a rare disorder .
however , its etiology is incompletely understood .
it may be familial or may be due to anoxic ischemic etiology .
although rare , it can affect one twin in a monoamniotic pregnancy , most likely due to early cord entanglement . |
nowadays there is an important distance between generations in our society , especially between senior citizens and young people , who do not regularly live together . in addition
, it has been demonstrated that the transfer of knowledge and experience , are the keys to sustainability of culture and tradition , as well as the transfer of values . in this context , it is necessary to promote actions and programmes that bring together these two generations , establish both time and space to share .
the intergenerational viure i conviure programme of caixa catalunya , of homeshare between senior citizens and young university students , as well as other similar european programmes , provide participants the necessary time and space for knowledge transfer . the experience gathered in this programme has shown us the importance of the relation between generations and the numerous values and benefits obtained by its participants .
values such as solidarity , tolerance , respect for other cultures and political views , among others , are clear examples . for over 12 years , more than 2000 homeshare couples in the viure i conviure programme have been formed and the programme s positive effect on senior citizens and young university students has been proven .
this experience of living together among generations , and other similar ones in europe , as well as other experiences between different groups ( for example , with persons with down syndrome ) demonstrate the relevance of the intergenerational programmes in long - term care in europe . | introductionnowadays there is an important distance between generations in our society , especially between senior citizens and young people , who do not regularly live together . in addition
, it has been demonstrated that the transfer of knowledge and experience , are the keys to sustainability of culture and tradition , as well as the transfer of values . in this context , it is necessary to promote actions and programmes that bring together these two generations , establish both time and space to share.descriptionthe intergenerational viure i conviure programme of caixa catalunya , of homeshare between senior citizens and young university students , as well as other similar european programmes , provide participants the necessary time and space for knowledge transfer .
the experience gathered in this programme has shown us the importance of the relation between generations and the numerous values and benefits obtained by its participants .
values such as solidarity , tolerance , respect for other cultures and political views , among others , are clear examples . for over 12 years , more than 2000 homeshare couples in the viure
i conviure programme have been formed and the programme s positive effect on senior citizens and young university students has been proven.conclusionthis experience of living together among generations , and other similar ones in europe , as well as other experiences between different groups ( for example , with persons with down syndrome ) demonstrate the relevance of the intergenerational programmes in long - term care in europe . |
there is growing data showing an increased association of seizures with alzheimer s , in both humans and animal models.1,2 estimates of prevalence vary , but it seems that about 1.5% to 10% of people with alzheimer s may experience seizure activity , with the highest prevalence in early onset alzheimers.3 this raises the question as to whether there is a subtype of alzheimer s that is seizure associated and may be linked to differential changes and possibly to differential treatment .
quinolinic acid ( qa ) is a possible mediator of both seizures and neuronal loss.4,5 in the brain , microglia are the most likely source for qa .
qa mediates neuronal excitotoxicity via the n - methyl - d - aspartate receptor ( nmdar ) and is usually induced by interferon - gamma ( ifny),6 although other factors are known to mediate an increase in the levels of indoleamine 2,3-dioxygenase ( ido ) , and subsequently qa.7,8 one such factor is il-18 .
il-18 is induced by stress,9 including in neurons.10 it is cleaved within the cell by caspase-1 , like il-1beta , and when released mediates an increase in ifny.11 such caspase-1 activation has upstream links to inflammasome induction , and therefore to wider models of neurodegeneration.12 it is therefore possible that il-18 , including via ifny , could be associated with an increase in the levels of ido activity and qa induction in microglia .
il-18 has been recently shown to increase glycogen synthase kinase 3-beta ( gsk-3b ) and tau hyperphosphorylation.13 would variations in the levels of il-18 be relevant to early onset seizure associated
il-18 has been shown to be increased in the brain in alzheimer s , and increased in the cerebral spinal fluid in mild cognitive impairment,14 and il-18 polymorphisms are associated with an increase in alzheimer s susceptibility , showing synergistic interactions with the apoe4 allele.15 interestingly the apoe4 allele , independent of dementia , is associated with an increase in the susceptibility to seizures.16 as to whether il-18 polymorphisms or increases in il-18 would synergistically interact with the apoe4 allele to induce an increase in seizures as well as alzheimer s remains to be examined .
it would be expected that il-18 , via an increase in gsk-3b , would increase the hyperphosphorylation of tau and enhance amyloid b ( ab ) production.17 recent data shows that ab may prime microglia - like cells for a sub - threshold concentration of ifny to induce ido / qa.18 60% of ido induction in ab primed cells is mediated by an ifny induced increase in tumor necrosis factor alpha ( tnfa ) , and the subsequent autocrine effects of tnfa .
previous data19 in this cell line show that ab effects are prevented when the sphingosine-1-phosphate receptor 1 ( s1p1r ) is k.o.d .
would variations in the levels / activity of the s1p1r be a significant modulator of such ab priming for subsequent ifny ?
this awaits experimental data , but it would suggest that the effects of ab , like lps or thrombin , in microglia is determined by an increase in the levels of gsk-3b and enhanced nadph oxidase activation.20 this would then modulate the s1p / ceramide ratio , as part of wider oxidant status driven lipid raft re - organization.21 presumably factors that increase the levels of endogenous anti - oxidants will modulate this oxidant driven priming and raft re - organization .
a number of factors inhibit gsk-3b and nadph oxidase in microglia , including lithium,22 resveratrol,23 and melatonin.24 all are associated with an increase in the phosphorylation , and inhibition , of gsk-3b , and therefore leading to an increase in nf - e2-related factor ( nrf-2 ) and endogenous anti - oxidants .
however , it is possible that il-18 , independent of ifny , can increase ido , as shown in other cell types.25 would il-18 directly mediate an increase in ido ?
some unpublished data suggests that this could be so.26 as to whether ab primes microglia for il-18 , as it does for ifny , remains to be determined .
il-18 seems to play a role in changing the most relevant factors associated with alzheimer s through its impact on tau , ab and possibly microglia threshold .
il-18 is currently being investigated for impacts at the blood brain barrier ( bbb ) .
should it induce gsk-3b and alter oxidant status in the bbb , then this could overlap it to the effects of peripheral lps , which mediates changes in rage ( receptor for advanced glycation end products ) and lrp-1 ( low density lipoprotein receptor - related protein-1).27 such changes lead to an increase in the influx and decrease in the efflux of ab over the bbb .
would il-18 , perhaps in conjunction with ab , parallel such oxidant associated changes in the bbb ? in human endothelia and pericyte lines , lps leads to an increase in the levels of abluminally released kynurenine.28 this seems likely to be taken up by astrocytic end - feet and rapidly converted to kynurenic acid ( ka ) .
would il-18 , with or without ab priming , modulate the ido and kynurenine pathways at the bbb ? such putative increases in ka
would likely be anti - epileptic , although it would also induce cognitive impairment , as in schizophrenia as well as in alzheimers.29 this is presuming ka release from astrocytes , perhaps in a targeted manner , to neurons .
however , in an inflammatory context , where bbb changes are occurring , then microglia may have closer proximity to the bbb , in conjunction with perivascular macrophages,30 and the kynurenine produced could be driven to qa production , and therefore contribute to excitotoxicity , and seizure induction .
an increase in kynurenine , qa and ka would suggest that more tryptophan is being driven down the kynurenine pathway , and less to serotonin and melatonin formation .
for example , losartan , via its active metabolite exp 3179 , mediates an increase in the akt / pgsk-3b / nrf-2/anti - oxidant paths .
this is achieved via the induction of vascular endothelial growth factor ( vegf ) and its effects at the vegf receptor 2 ( vegf r2).31 ab directly blocks the vegf r2,32 and so some of the anti - hypertensive and importantly anti - oxidant effects of losartan will be lost .
a shift to other anti - hypertensives may be useful . this would highlight the need for more dynamic and reactive prescribing , which in turn would be dependent on a more detailed knowledge of the processes of change , including the changes that seizure induction may indicate .
melatonin has also been shown to be protective in alzheimers,33 and has been shown to significantly decrease the levels of gsk-3b.34 would a significant decrease in melatonin interact with seizure susceptibility in alzheimer s ?
no current data directly answers this , although melatonin is known to have anti - epileptic effects.35 melatonin also reverses some of the other cellular changes that are associated with alzheimer s , including a decrease in the longevity protein sirtuin-1,36 a decrease in pgc-1a ( peroxisome proliferator - activated receptor - gamma , coactivator-1alpha)37 and a decrease in oxidative phosphorylation.38 would variations in melatonin be associated with seizure susceptibility , and perhaps the modulation of the il-18/ifny induced increases in ido / qa in seizure associated alzheimer s ?
melatonin is known to modulate bbb permeability , and this may be relevant to changes in brain ab levels , as suggested above . also the kynurenine aminotransferases ( kats ) are sensitive to oxidative stress.39 a decrease in ka arising from such oxidative modulation may allow more kynurenine to form qa .
there is one paper showing that astrocytes are able to produce melatonin when adequate serotonin is present.40 given the anti - seizure , anti - cortisol and cortisol modulating effects of melatonin,41 then such induction by astrocytes would be a potential local target for drugs to induce .
it would seem likely that such astrocyte derived melatonin would modulate seizures , stress / il-18 as well as microglia and bbb oxidant status and associated changes , as shown in the summary figure . in conclusion
, an argument can be made for the role of stress induced increases in il-18 , perhaps via ifny and/or ab priming , in the modulation of ido in both microglia and endothelia . in microglia
an increase in the levels of qa would be associated with both seizures and neuronal loss , and these effects may be potentiated by the apoe4 allele . as to
whether such pathways constitute a sub - type of alzheimer s , or are differentially activated along a continuum in all people with alzheimer s remains to be determined .
further research on the processes may lead to a better treatment strategy for this putative sub - type of alzheimer s . | emergent seizures are common in alzheimer s disease ( ad ) , although the mechanisms mediating this are unknown .
it is proposed that stress induced interleukin-18 ( il-18 ) , via interferon - gamma ( ifny ) and independently , increases indoleamine 2,3-dioxygenase ( ido ) and subsequent quinolinic acid ( qa ) in microglia .
qa increases seizures and concurrently contributes to neuronal loss via excitotoxicity .
the apoe4 allele interacts with il-18 polymorphisms to increase the risk of ad , and seems likely to potentiate the emergence of seizures .
concurrent changes in ido and the kynurenine pathways at the blood - brain - barrier ( bbb ) have implications for treatment , including in the efficacy of different anti - hypertensives . melatonin is proposed to inhibit these overlapping excitotoxic and neurodegenerative processes , and would be a useful adjunctive treatment . |
peripheral artery disease ( pad ) is a common manifestation of atherosclerosis and affects 8 million people in the united states .
pad is associated with increased risk of death and adverse cardiovascular events , causes leg pain with exertion , impairs functional capacity and quality of life , and is frequently associated with coronary , cerebral , and renal artery disease .
pad involves the arteries distal to the aortic bifurcation in a nonuniform manner , and factors such as arterial geometry and anatomic , cellular , or biochemical properties of the arterial wall may influence disease location . for example , iliac arteries are relatively elastic , whereas infragenicular arteries contain progressively more muscular elements .
several modalities have been used to define affected arteries in pad , including doppler , computed tomography angiography , contrastenhanced magnetic resonance angiography , and digital subtraction angiography .
digital subtraction angiography is considered the gold standard for assessing location and severity of pad but is not generalizable to the entire pad population because patients with severe and symptomatic disease are more likely to be referred for angiography . on the other hand
, doppler evaluation is relatively inexpensive , easily performed , and widely used in noninvasive vascular laboratories .
several studies have shown that the distribution , extent , and progression of pad are influenced by cardiovascular risk factors , but the findings are not consistent .
a few studies suggest that the prognosis of patients with pad varies according to disease localization .
the goal of the present study was to describe the patterns of disease location in patients with known or suspected pad who underwent evaluation in a noninvasive vascular laboratory that included noninvasive doppler examination and to examine the association of such patterns with survival .
the study population was drawn from 22 859 consecutive outpatients who underwent lower extremity arterial evaluation in the noninvasive vascular laboratory of the gonda vascular center , mayo clinic , rochester , minnesota , between january 1 , 1998 , and december 31 , 2007 .
we identified 8930 pad patients who ( 1 ) had appropriate research authorization , ( 2 ) were 18 years at the time of arterial evaluation , ( 3 ) resided within a 500mile radius of rochester , minnesota ( to ensure appropriate information would be available in the electronic medical record ) , ( 4 ) were not hospitalized at the time of arterial evaluation , ( 5 ) had results available from both arterial and doppler ultrasound evaluation , and ( 6 ) had an ankle brachial index ( abi ) 0.90 .
an additional reference group of 3801 patients with normal abi ( 1.00 to 1.30 ) and no evidence of disease from doppler ultrasound evaluation was identified in the same manner , resulting in a total of 12 731 unique patients available for analysis .
the study was approved by the mayo clinic institutional review board and informed consent was obtained from participants .
noninvasive arterial evaluation was performed in the vascular laboratory of the mayo clinic as described in detail in the supplement .
the mayo vascular laboratory is certified by the intersocietal commission for the accreditation of vascular laboratories . quality control and maintenance procedures
are in place as required by the intersocietal commission for the accreditation of vascular laboratories , including for interpretation of doppler waveforms ( see supplement for details ) .
patients were determined to have pad if they had a resting or postexercise abi 0.90 .
disease location was inferred from the results of continuouswave doppler interrogation of lower extremity arteries .
a doppler probe is placed directly over the artery and held at a 45 to 60degree angle to obtain a doppler waveform from each major lower extremity artery , including common femoral ( cf ) , superficial femoral , popliteal , posterior tibial ( pt ) , and dorsalis pedis ( dp ) arteries .
a standardized algorithm was used by highly trained vascular laboratory technicians to categorize the doppler signals ( see supplement ) .
triphasic , normal , and biphasic doppler signals were considered normal , whereas reduced biphasic , slightly abnormal , abnormal , monophasic , and absent signals were considered abnormal .
the rating of severity of abnormal doppler signals was defined as follows : reduced biphasic < slightly abnormal < abnormal < monophasic < absent .
the cf artery was assessed at rest and again after exercise if the patient was able to walk on a treadmill ; all other vessels were assessed only at rest .
disease status was assigned for each leg at the proximal and distal regions on the basis of involvement of the cf and pt / dp arteries , respectively .
the most severe doppler signal was used if multiple results were available at the same arterial location for the same leg .
therefore , each person had up to 4 disease status assignments , whereas missing assignments reflected evaluations not performed .
cf doppler results were used to characterize proximal disease status as normal , abnormal only after exercise , or abnormal at rest .
pt / dp doppler results were used to characterize distal disease status as normal or abnormal at rest . to address the possibility that doppler abnormality in distal arteries might reflect reduced flow in the proximal vessels , we considered distal disease to be present only when the doppler signals worsened at the pt / dp arteries compared with the readings at the cf and/or superficial femoral / popliteal arteries , using the severity rating shown above .
although each person had at least one doppler signal available , 905 ( 7.1% ) patients were only assessed at the distal arteries and 54 ( 0.4% ) patients were only assessed at the proximal vessels .
demographic characteristics were obtained from the mayo electronic medical record , as detailed in the supplement .
cardiovascular risk factors were ascertained from the electronic medical record using previously validated algorithms that have good sensitivity and specificity compared with manual chart abstraction .
the followup period for each patient was the time between first arterial evaluation and date of death or final censoring date ( september 30 , 2009 ) .
statistical analyses were performed using sas version 9.3 ( sas institute inc , cary , nc ) .
continuous variables were expressed as meanstandard deviation , whereas categorical variables were expressed as number ( percentage ) .
univariable and multivariable generalized estimating equations logistic regression models were fit to identify variables associated with abnormal resting doppler results within each region separately , adjusting for age and sex .
to assess whether the risk factor and comorbidity associations differed between proximal and distal locations , both regions and both legs were analyzed as separate observations in the same generalized estimating equation model with terms for location and for the interactions between location ( proximal or distal ) and risk factors .
for this analysis , patients with any abnormal doppler results in the proximal region only after exercise for the left and/or right leg were excluded ( n=2324 ) to allow comparison of characteristics of patients with abnormalities in the proximal and distal regions at rest .
each patient had between 1 and 4 doppler results available , and generalized estimating equation models were used to account for repeated measures .
an exchangeable correlation structure was used for analysis within each region ( up to 2 observations per patient ) .
those patients missing results in both legs within a particular region were excluded from the corresponding regional analysis ( n=905 missing proximal results , n=54 missing distal results ) .
univariable and multivariable cox proportional hazards regression was used to estimate hazard ratios for death according to the presence or absence of disease in each region ( proximal or distal ) using the most severe disease status across both legs within each region . for this analysis ,
proximal doppler results were classified as an ordinal variable , with normal as the reference level , postexercise abnormality as the intermediate level , and resting abnormality as the highest level . to analyze the joint effect of proximal and distal disease without excluding patients in whom either proximal or distal information was missing , we used logistic regression models to calculate the predicted probabilities of proximal and distal disease and used them as imputations for the missing disease status variables .
both proximal and distal disease status variables were then included in the cox models , both as main effects and including their interaction .
adjustment was performed sequentially for ( 1 ) age and sex ; ( 2 ) age , sex , obesity , smoking , diabetes , hypertension , dyslipidemia , coronary heart disease ( chd ) , heart failure , chronic kidney disease ( ckd ) , cerebrovascular disease ( cvd ) , chronic obstructive pulmonary disease ( copd ) , malignancy , and medication ( lipidlowering and aspirin ) use ; and finally ( 3 ) also for resting abi .
the study population was drawn from 22 859 consecutive outpatients who underwent lower extremity arterial evaluation in the noninvasive vascular laboratory of the gonda vascular center , mayo clinic , rochester , minnesota , between january 1 , 1998 , and december 31 , 2007 .
we identified 8930 pad patients who ( 1 ) had appropriate research authorization , ( 2 ) were 18 years at the time of arterial evaluation , ( 3 ) resided within a 500mile radius of rochester , minnesota ( to ensure appropriate information would be available in the electronic medical record ) , ( 4 ) were not hospitalized at the time of arterial evaluation , ( 5 ) had results available from both arterial and doppler ultrasound evaluation , and ( 6 ) had an ankle brachial index ( abi ) 0.90 .
an additional reference group of 3801 patients with normal abi ( 1.00 to 1.30 ) and no evidence of disease from doppler ultrasound evaluation was identified in the same manner , resulting in a total of 12 731 unique patients available for analysis .
the study was approved by the mayo clinic institutional review board and informed consent was obtained from participants .
noninvasive arterial evaluation was performed in the vascular laboratory of the mayo clinic as described in detail in the supplement .
the mayo vascular laboratory is certified by the intersocietal commission for the accreditation of vascular laboratories . quality control and maintenance procedures
are in place as required by the intersocietal commission for the accreditation of vascular laboratories , including for interpretation of doppler waveforms ( see supplement for details ) .
patients were determined to have pad if they had a resting or postexercise abi 0.90 .
disease location was inferred from the results of continuouswave doppler interrogation of lower extremity arteries .
a doppler probe is placed directly over the artery and held at a 45 to 60degree angle to obtain a doppler waveform from each major lower extremity artery , including common femoral ( cf ) , superficial femoral , popliteal , posterior tibial ( pt ) , and dorsalis pedis ( dp ) arteries .
a standardized algorithm was used by highly trained vascular laboratory technicians to categorize the doppler signals ( see supplement ) .
triphasic , normal , and biphasic doppler signals were considered normal , whereas reduced biphasic , slightly abnormal , abnormal , monophasic , and absent signals were considered abnormal .
the rating of severity of abnormal doppler signals was defined as follows : reduced biphasic < slightly abnormal < abnormal < monophasic < absent .
the cf artery was assessed at rest and again after exercise if the patient was able to walk on a treadmill ; all other vessels were assessed only at rest .
disease status was assigned for each leg at the proximal and distal regions on the basis of involvement of the cf and pt / dp arteries , respectively .
the most severe doppler signal was used if multiple results were available at the same arterial location for the same leg .
therefore , each person had up to 4 disease status assignments , whereas missing assignments reflected evaluations not performed .
cf doppler results were used to characterize proximal disease status as normal , abnormal only after exercise , or abnormal at rest .
/ dp doppler results were used to characterize distal disease status as normal or abnormal at rest . to address the possibility that doppler abnormality in distal arteries might reflect reduced flow in the proximal vessels , we considered distal disease to be present only when the doppler signals worsened at the pt / dp arteries compared with the readings at the cf and/or superficial femoral / popliteal arteries , using the severity rating shown above .
although each person had at least one doppler signal available , 905 ( 7.1% ) patients were only assessed at the distal arteries and 54 ( 0.4% ) patients were only assessed at the proximal vessels .
demographic characteristics were obtained from the mayo electronic medical record , as detailed in the supplement .
cardiovascular risk factors were ascertained from the electronic medical record using previously validated algorithms that have good sensitivity and specificity compared with manual chart abstraction .
the followup period for each patient was the time between first arterial evaluation and date of death or final censoring date ( september 30 , 2009 ) .
statistical analyses were performed using sas version 9.3 ( sas institute inc , cary , nc ) .
continuous variables were expressed as meanstandard deviation , whereas categorical variables were expressed as number ( percentage ) .
univariable and multivariable generalized estimating equations logistic regression models were fit to identify variables associated with abnormal resting doppler results within each region separately , adjusting for age and sex . to assess whether the risk factor and comorbidity associations differed between proximal and distal locations , both regions and both legs were analyzed as separate observations in the same generalized estimating equation model with terms for location and for the interactions between location ( proximal or distal ) and risk factors .
for this analysis , patients with any abnormal doppler results in the proximal region only after exercise for the left and/or right leg were excluded ( n=2324 ) to allow comparison of characteristics of patients with abnormalities in the proximal and distal regions at rest .
each patient had between 1 and 4 doppler results available , and generalized estimating equation models were used to account for repeated measures .
an exchangeable correlation structure was used for analysis within each region ( up to 2 observations per patient ) .
those patients missing results in both legs within a particular region were excluded from the corresponding regional analysis ( n=905 missing proximal results , n=54 missing distal results ) .
univariable and multivariable cox proportional hazards regression was used to estimate hazard ratios for death according to the presence or absence of disease in each region ( proximal or distal ) using the most severe disease status across both legs within each region .
for this analysis , proximal doppler results were classified as an ordinal variable , with normal as the reference level , postexercise abnormality as the intermediate level , and resting abnormality as the highest level . to analyze the joint effect of proximal and distal disease without excluding patients in whom either proximal or distal information was missing , we used logistic regression models to calculate the predicted probabilities of proximal and distal disease and used them as imputations for the missing disease status variables .
both proximal and distal disease status variables were then included in the cox models , both as main effects and including their interaction .
adjustment was performed sequentially for ( 1 ) age and sex ; ( 2 ) age , sex , obesity , smoking , diabetes , hypertension , dyslipidemia , coronary heart disease ( chd ) , heart failure , chronic kidney disease ( ckd ) , cerebrovascular disease ( cvd ) , chronic obstructive pulmonary disease ( copd ) , malignancy , and medication ( lipidlowering and aspirin ) use ; and finally ( 3 ) also for resting abi .
after applying the exclusion criteria mentioned above , 12 731 patients were identified for analyses .
postexercise proximal disease was present in 10.2% , resting proximal disease in 18.0% , distal disease in 13.6% , postexercise proximal and distal disease in 4.0% , resting proximal and distal disease in 12.5% , and no proximal or distal disease in 41.7% ( table 1 ) .
patient characteristics by doppler results shown are meanstandard deviation for continuous variables and frequency ( % ) for categorical variables and missing values .
proximal and distal disease for each subject is classified separately based on the most severe disease status ( no disease < postexercise disease < resting disease ) across both legs .
those with no proximal doppler assessments were classified based on imputed disease status ( similarly for those with no distal doppler assessment ) .
abi indicates ankle brachial index ; bp , blood pressure ; chd , coronary heart disease ; ckd , chronic kidney disease ; cli , critical limb ischemia ; copd , chronic obstructive pulmonary disease ; cvd , cerebrovascular disease .
there were significant associations between older age and male sex with resting distal disease ( both p<0.001 ) and between older age and resting proximal disease ( p<0.001 ) , as shown in table 2 .
these associations were stronger with distal disease than with proximal disease ( interaction p<0.001 and p=0.004 , respectively ) .
the presence of cardiovascular risk factors and comorbidities were compared after adjustment for age and sex . among cardiovascular risk factors ,
body mass index < 30 , smoking , diabetes , hypertension , and dyslipidemia were significantly associated with proximal disease , whereas diabetes and hypertension were significantly associated with distal disease . in models that considered interactions between disease location and risk factors ,
diabetes was more strongly associated with distal disease ( interaction p<0.001 ) , whereas smoking and hypertension were more strongly associated with proximal disease ( interaction p<0.001 and p=0.005 , respectively ) ( table 2 ) .
risk factors and comorbid conditions associated with resting disease status : univariable regression analyses proximal and distal results are reported from models within each region separately and reflect number of persons with specific regional results .
interaction results are reported from the model with all data together and required data from either or both regions .
people missing proximal results ( n=905 ) were excluded only from the proximal region analysis , people missing distal results ( n=54 ) were excluded only from the distal region analysis .
patients with postexercise proximal disease in either leg ( n=2324 ) were excluded from this analysis .
abi indicates ankle brachial index ; chd , coronary heart disease ; 95% ci , 95% confidence interval ; ckd , chronic kidney disease ; copd , chronic obstructive pulmonary disease ; cvd , cerebrovascular disease ; or , odds ratio . per 10year increase . per 0.1unit increase .
among comorbid conditions , chd , heart failure , ckd , cvd , copd , and critical limb ischemia were associated with both proximal and distal disease .
chd , cvd , and copd were more strongly associated with proximal disease ( all interaction p<0.001 ) , whereas heart failure and critical limb ischemia were more strongly associated with distal disease ( both interactions p<0.001 ) ; see table 2 . of the remaining variables , lower abi was more strongly associated with proximal disease than with distal disease ( both interactions p<0.001 ; table 2 ) .
use of lipidlowering medication was positively associated with proximal disease and negatively associated with distal disease , whereas aspirin use was only associated with proximal disease .
multivariable models were fit to identify joint associations of risk factors and comorbid conditions with proximal and distal disease ( table 3 ) .
results were similar to those from univariable analysis except that age , diabetes , heart failure , ckd , and use of aspirin or lipidlowering medication were no longer significantly independently associated with proximal disease , whereas chd , ckd , and copd were no longer associated with distal disease . in the multivariable models ,
male sex was now inversely associated with proximal disease , and body mass index < 30 was now associated with distal disease . risk factors and comorbid conditions associated with resting disease status : multivariable regression analyses proximal and distal results are reported from models within each region separately and reflect number of persons with specific regional results .
interaction results are reported from the model with all data together and required data from either or both regions.(ie , those with at least one doppler assessment ) .
people missing proximal results ( n=905 ) were excluded only from the proximal region analysis , people missing distal results ( n=54 ) were excluded only from the distal region analysis .
patients with postexercise proximal disease in either leg ( n=2324 ) were excluded from this analysis .
chd indicates coronary heart disease ; ci , confidence interval ; ckd , chronic kidney disease ; copd , chronic obstructive pulmonary disease ; cvd , cerebrovascular disease ; or , odds ratio . per 10year increase
. of the 12 731 patients followed for a mean 5.93.1 years , 3039 ( 23.9% ) died .
unadjusted kaplan meier survival curves according to proximal and distal disease status are shown in figure .
we estimated the relative hazard of death for proximal and distal disease together , using multivariable cox proportional hazards regression both with and without the interaction between proximal and distal disease ( table 4 ) . in the main effects model , after adjustment for age and sex , the relative hazard of death was 1.3 for proximal disease only and 1.5 for distal disease only . however , there was a highly significant interaction ( p<0.001 ) such that the presence of both proximal and distal disease was not associated with higher risk than the presence of either disease separately ( hr , 1.4 proximal only ; hr , 1.9 distal only ; hr , 2.2 proximal and distal ) . in the model that further adjusted for risk factors and comorbidities ,
, there was no significant association between proximal disease and death , whereas the hazard ratio for death was 1.2 for those with distal disease .
the same models were fitted on a subset of patients , excluding those with critical limb ischemia , with similar findings ( see table s1 ) .
survival curves adjusted for age and adjusted for all covariates in the final survival model are provided in the supplement .
hazard of death associated with disease status proximal disease was defined as an ordinal variable : no disease ( reference level ) , postexercise disease ( intermediate level ) , resting disease ( highest level ) .
distal disease was defined as a binary variable : no disease ( reference level ) , resting disease ( highest level ) .
the disease status at each region for each person was defined as the most severe disease status across both legs .
those with no proximal doppler assessment were classified based on imputed disease status ( similarly for those with no distal doppler assessment ) .
model a , age and sex ; model b , age , sex , obesity , chd , cerebrovascular disease , heart failure , diabetes , hypertension , chronic kidney disease , malignancy , chronic obstructive pulmonary disease , smoking , lipidlowering medication use , and aspirin use ; model c , model b variables+resting abi .
abi indicates ankle brachial index ; chd , coronary heart disease ; 95% ci , confidence interval ; hr , hazard ratio . interaction of proximal and distal disease status significant at p<0.001 .
meier survival curves for survival free of death over 12 years of followup by proximal and distal disease status .
there were significant associations between older age and male sex with resting distal disease ( both p<0.001 ) and between older age and resting proximal disease ( p<0.001 ) , as shown in table 2 .
these associations were stronger with distal disease than with proximal disease ( interaction p<0.001 and p=0.004 , respectively ) .
the presence of cardiovascular risk factors and comorbidities were compared after adjustment for age and sex . among cardiovascular risk factors ,
body mass index < 30 , smoking , diabetes , hypertension , and dyslipidemia were significantly associated with proximal disease , whereas diabetes and hypertension were significantly associated with distal disease . in models that considered interactions between disease location and risk factors ,
diabetes was more strongly associated with distal disease ( interaction p<0.001 ) , whereas smoking and hypertension were more strongly associated with proximal disease ( interaction p<0.001 and p=0.005 , respectively ) ( table 2 ) .
risk factors and comorbid conditions associated with resting disease status : univariable regression analyses proximal and distal results are reported from models within each region separately and reflect number of persons with specific regional results .
interaction results are reported from the model with all data together and required data from either or both regions .
people missing proximal results ( n=905 ) were excluded only from the proximal region analysis , people missing distal results ( n=54 ) were excluded only from the distal region analysis .
patients with postexercise proximal disease in either leg ( n=2324 ) were excluded from this analysis .
abi indicates ankle brachial index ; chd , coronary heart disease ; 95% ci , 95% confidence interval ; ckd , chronic kidney disease ; copd , chronic obstructive pulmonary disease ; cvd , cerebrovascular disease ; or , odds ratio . per 10year increase . per 0.1unit increase .
among comorbid conditions , chd , heart failure , ckd , cvd , copd , and critical limb ischemia were associated with both proximal and distal disease .
chd , cvd , and copd were more strongly associated with proximal disease ( all interaction p<0.001 ) , whereas heart failure and critical limb ischemia were more strongly associated with distal disease ( both interactions p<0.001 ) ; see table 2 . of the remaining variables ,
lower abi was more strongly associated with proximal disease than with distal disease ( both interactions p<0.001 ; table 2 ) .
use of lipidlowering medication was positively associated with proximal disease and negatively associated with distal disease , whereas aspirin use was only associated with proximal disease .
multivariable models were fit to identify joint associations of risk factors and comorbid conditions with proximal and distal disease ( table 3 ) .
results were similar to those from univariable analysis except that age , diabetes , heart failure , ckd , and use of aspirin or lipidlowering medication were no longer significantly independently associated with proximal disease , whereas chd , ckd , and copd were no longer associated with distal disease . in the multivariable models ,
male sex was now inversely associated with proximal disease , and body mass index < 30 was now associated with distal disease .
risk factors and comorbid conditions associated with resting disease status : multivariable regression analyses proximal and distal results are reported from models within each region separately and reflect number of persons with specific regional results .
interaction results are reported from the model with all data together and required data from either or both regions.(ie , those with at least one doppler assessment ) .
people missing proximal results ( n=905 ) were excluded only from the proximal region analysis , people missing distal results ( n=54 ) were excluded only from the distal region analysis .
patients with postexercise proximal disease in either leg ( n=2324 ) were excluded from this analysis .
chd indicates coronary heart disease ; ci , confidence interval ; ckd , chronic kidney disease ; copd , chronic obstructive pulmonary disease ; cvd , cerebrovascular disease ; or , odds ratio . per 10year increase .
of the 12 731 patients followed for a mean 5.93.1 years , 3039 ( 23.9% ) died .
unadjusted kaplan meier survival curves according to proximal and distal disease status are shown in figure .
we estimated the relative hazard of death for proximal and distal disease together , using multivariable cox proportional hazards regression both with and without the interaction between proximal and distal disease ( table 4 ) . in the main effects model ,
after adjustment for age and sex , the relative hazard of death was 1.3 for proximal disease only and 1.5 for distal disease only .
however , there was a highly significant interaction ( p<0.001 ) such that the presence of both proximal and distal disease was not associated with higher risk than the presence of either disease separately ( hr , 1.4 proximal only ; hr , 1.9 distal only ; hr , 2.2 proximal and distal ) . in the model that further adjusted for risk factors and comorbidities , the same pattern was seen . in the final model that adjusted for resting abi
, there was no significant association between proximal disease and death , whereas the hazard ratio for death was 1.2 for those with distal disease .
the same models were fitted on a subset of patients , excluding those with critical limb ischemia , with similar findings ( see table s1 ) .
survival curves adjusted for age and adjusted for all covariates in the final survival model are provided in the supplement .
hazard of death associated with disease status proximal disease was defined as an ordinal variable : no disease ( reference level ) , postexercise disease ( intermediate level ) , resting disease ( highest level ) .
distal disease was defined as a binary variable : no disease ( reference level ) , resting disease ( highest level ) .
the disease status at each region for each person was defined as the most severe disease status across both legs .
those with no proximal doppler assessment were classified based on imputed disease status ( similarly for those with no distal doppler assessment ) .
model a , age and sex ; model b , age , sex , obesity , chd , cerebrovascular disease , heart failure , diabetes , hypertension , chronic kidney disease , malignancy , chronic obstructive pulmonary disease , smoking , lipidlowering medication use , and aspirin use ; model c , model b variables+resting abi .
abi indicates ankle brachial index ; chd , coronary heart disease ; 95% ci , confidence interval ; hr , hazard ratio .
meier survival curves for survival free of death over 12 years of followup by proximal and distal disease status .
female sex , smoking , hypertension , dyslipidemia , chd , cvd , and copd were more significantly associated with proximal disease , whereas older age , male sex , diabetes , heart failure , and critical limb ischemia were more significantly associated with distal disease .
second , patients with distal disease had poorer prognosis compared with patients without distal disease , independent of age , sex , comorbid conditions , medication ( lipidlowering and aspirin ) use and resting abi , whereas patients with proximal disease showed no difference in prognosis after similar adjustment compared with patients without proximal disease .
like most atherosclerotic vascular disease , pad affects the arterial bed in a nonuniform fashion .
some investigators define aortoiliac arteries as proximal arteries , and femoral / popliteal and infragenicular arteries as distal arteries .
others define arteries above the knee and even above the ankle as proximal . in the present study , we classified the disease location as proximal and/or distal on the basis of involvement at the cf and pt / dp anatomical levels , respectively , as ascertained by noninvasive doppler evaluation .
diehm et al , in 2659 patients undergoing endovascular intervention for pad , classified disease location of the 4205 atherosclerotic lesions as iliac , femoralpopliteal , and infragenicular .
similar results were reported by vogt et al . among 575 pad patients with only singlesegment disease ascertained by noninvasive segmental blood pressure gradients ,
femoralpopliteal disease was present in 47.3% , aortoiliac disease in 33.6% , and tibioperoneal disease in 19.1% of patients .
ozkan et al studied 626 patients with symptomatic pad who underwent angiography and found that the crural segment ( from the anterior tibial arteries to the ankle ) was the site most commonly affected ( 70% ) .
of 8930 patients with pad in the present study , cf was more commonly affected than the pt / dp location ( 57.6% and 42.9% , respectively ) . because distal doppler abnormality can be secondary to reduced flow in a proximal vessel , to avoid misclassification , a worsening of doppler signals was required to label disease as distal .
predilection for certain anatomical sites may be a result of differences in wall composition , arterial diameter , or hemodynamic factors .
in addition , certain conventional risk factors may predispose differentially to proximal versus distal disease in pad patients .
several clinical and epidemiologic studies have investigated the association of risk factors with disease location in pad . in the present study
, we found that those with only distal disease were older ( 73.011.0 years ) , consistent with the results of previous studies .
disease location also significantly differed between men and women , with men more often having distal disease than proximal disease .
some studies reported that men more often had iliac disease , whereas a study including younger ( < 50 years ) patients with pad showed that female sex was associated with the aortoiliac disease .
of the conventional risk factors for pad , smoking status and diabetes mellitus were strongly associated with disease distribution . in the present study , history of smoking was most frequent in patients with only resting proximal disease ( 93.0% ) and was more significantly associated with proximal disease than with distal disease ( interaction p<0.001 ) , consistent with other reports .
our univariable results are concordant with prior studies showing that diabetes was more strongly associated with distal disease than with proximal disease ( interaction p<0.001 ) . in multivariable regression analyses ,
smoking history was again more associated with proximal disease , whereas diabetes was more strongly associated with distal disease .
we also found that dyslipidemia was also more strongly associated with proximal disease than with distal disease . in ozkan et al 's study ,
a study of younger patients ( mean age , 42.7 4.2 years ) with pad showed that dyslipidemia ( based on either total cholesterol or triglyceride level ) was more prevalent in aortoiliac disease than in distal disease .
the data on the association between hypertension and pad localization are not consistent , either . in the present study , history of hypertension
however , a trend toward more distal lesions in hypertensive patients was noted in other studies .
the prognosis of pad patients has been reported to differ by disease location . in the present study ,
patients with distal disease had an increased risk of death compared with those with normal distal signals even after adjustment for risk factors for atherosclerosis , comorbid conditions , and resting abi levels , whereas the risk of death was not significantly increased among those with a proximal disease location after adjustment for resting abi .
two studies that assessed pad patients with flow velocity by doppler ultrasound and segmental blood pressure ratios showed higher mortality in proximal pad . in a study of 400 patients with pad , ascertained by digital subtraction angiography
patients in this study were hospitalized , mostly men ( 77% ) and had pad severe enough to be referred for angiography , in contrast to our cohort of 12 731 consecutive patients with known or suspected pad referred for noninvasive evaluation in the outpatient setting .
disease location was based on angiographic appearance whereas we assigned disease location based on doppler .
we have demonstrated that patients with distal disease have poorer survival than those without distal disease independent of relevant covariates ( hr , 1.2 ; 95% ci , 1.1 to 1.3 ) .
a previous study showed that multilevel disease was associated with greater mortality in pad patients . in the present study ,
patients with multilevel disease had more prevalent chd and cvd compared with patients with only distal disease , which may have led to earlier treatment in this group .
in previous studies , patients with chd and pad , when compared with patients with pad alone , received more cardiovascular medical therapy , reducing their longterm mortality .
van kuijk et al reported that pad patients with chd or / and cvd received better medical treatment compared with patients with pad alone .
to the best of our knowledge , the study sample ( n=12 731 ) contained the largest cohort of patients with pad ( n=8930 ) for whom disease location has been ascertained with doppler .
all the patients included underwent doppler evaluation in an accredited noninvasive vascular laboratory , and disease location was ascertained by uniform methods .
patients in our study were identified and evaluated from the noninvasive vascular laboratory of a tertiarycare center , and some degree of referral bias may have been present .
use of medical record review to ascertain risk factors may be associated with reporting bias .
we used the lower of the two abis from each leg whereas conventionally the higher abi is used .
we based our choice on a study that demonstrated that the abi based on the lower ankle pressure identifies a greater number of patients at risk for adverse cardiovascular events than an abi based on the higher ankle pressure . while the doppler criteria used to assign disease location in this study are commonly used in clinical vascular laboratories we can not exclude some degree of misclassification .
however , doppler derived inference of disease location is well correlated with that derived from angiography ( see supplement ) , and the latter is not practical in large studies given its cost and invasive nature .
missing data were also a limitation , as a number of patients ( n=905 ) had doppler evaluations performed only at the distal arteries . to address this ,
results from the proximal and distal regions separately were reported , as well as results using the combined data .
to the best of our knowledge , the study sample ( n=12 731 ) contained the largest cohort of patients with pad ( n=8930 ) for whom disease location has been ascertained with doppler .
all the patients included underwent doppler evaluation in an accredited noninvasive vascular laboratory , and disease location was ascertained by uniform methods .
patients in our study were identified and evaluated from the noninvasive vascular laboratory of a tertiarycare center , and some degree of referral bias may have been present .
use of medical record review to ascertain risk factors may be associated with reporting bias .
we used the lower of the two abis from each leg whereas conventionally the higher abi is used .
we based our choice on a study that demonstrated that the abi based on the lower ankle pressure identifies a greater number of patients at risk for adverse cardiovascular events than an abi based on the higher ankle pressure . while the doppler criteria used to assign disease location in this study
are commonly used in clinical vascular laboratories we can not exclude some degree of misclassification .
however , doppler derived inference of disease location is well correlated with that derived from angiography ( see supplement ) , and the latter is not practical in large studies given its cost and invasive nature .
missing data were also a limitation , as a number of patients ( n=905 ) had doppler evaluations performed only at the distal arteries . to address this ,
results from the proximal and distal regions separately were reported , as well as results using the combined data .
pad involves > 1 arterial location , with the cf being the most commonly affected .
older age , male sex , diabetes , heart failure , and critical limb ischemia were more significantly associated with distal disease , whereas female sex , smoking , hypertension , dyslipidemia , chd , cvd , and copd were more significantly associated with proximal disease .
patients with distal disease had poorer prognosis compared with patients without distal disease , independent of age , sex , comorbid conditions , medication ( lipidlowering and aspirin ) use , and resting abi , whereas patients with proximal disease showed no difference in prognosis after similar adjustment compared with patients without proximal disease .
the implications for epidemiologic studies , including biomarker and genetic association studies as well as drug trials , are substantial .
| backgroundwe investigated whether disease location influences survival in patients with peripheral arterial disease.methods and resultspatients ( n=12 731 ; mean age , 67.512.7 years ; 57.4% male ) who underwent outpatient noninvasive lower extremity arterial evaluation were followed up for 5.93.1 years for allcause mortality .
peripheral arterial disease ( n=8930 ) was defined as a resting or postexercise anklebrachial index ( abi ) 0.90 , and normal abi ( n=3 801 ) was defined as a resting and postexercise abi of 1.00 to 1.30 . presence or absence of disease at the proximal location or distal location was determined on the basis of doppler signals in leg arteries ; 42% had no pd or dd , 45% had proximal ( 14% postexercise pd only ) , 30% had distal disease , 17% had both proximal and distal disease , 28% had proximal only and 14% had distal only .
we performed multivariable logistic regression to identify factors associated with disease location , and cox proportional hazard regression to assess the respective effects of proximal or distal disease on survival .
older age , male sex , diabetes , heart failure , and critical limb ischemia were associated with distal disease , whereas female sex , smoking , hypertension , dyslipidemia , coronary heart disease , cerebrovascular disease , chronic obstructive pulmonary disease , and critical limb ischemia were associated with proximal disease . over a mean followup of 5.93.1 years
, 3039 patients ( 23.9% ) died .
after adjustment for potential confounders , the hazard ratios ( hrs ) of death associated with pd only and dd only were 1.3 ( 1.3 to 1.4 ) and 1.5 ( 1.4 to 1.6 ) , respectively .
after additional adjustment for resting abi , there was no significant association between proximal disease and death , whereas the association of distal disease with death remained significant ( hr , 1.2 ; 95% ci , 1.1 to 1.3).conclusionsin patients with peripheral arterial disease , proximal and distal disease locations were associated with distinctive risk factor and comorbidity profiles .
distal disease was associated with worse survival even after adjustment for risk factors , comorbidities , and resting abi . |
a 38-year - old man was injured in a car accident while driving , sustaining a left acetabular posterior wall fracture ( fig .
1 ) . we explain to patient that it can be treated with non - weight bearing for 4 to 6 weeks , but he denied conservative treatment because he must return to his job .
so , we decided to perform arthroscopic reduction and screw fixation after three days from trauma . under spinal anesthesia ,
the patient was positioned supine on a fracture table with the affected limb in traction and the opposite limb .
we made three portal ( anterolateral , anterior , and posterolateral portals ) , the fracture fragment of the acetabular posterior wall was visualized after hematoma evacuation ( fig .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire through posterolateral portal .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization ( fig .
3 ) . postoperative radiographs and computed tomography ( ct ) was performed , the fragment was satisfactory reduced and compressed ( fig .
, the patient discharged after care for postoperative wound and went back to normal life with crutch .
he did not complain pain or discomfort after six months from the surgery , began heavy sports activities .
a 41-year - old man was injured in a car accident while driving , sustaining a right acetabular posterior wall fracture ( fig .
5c ) . skeletal traction was initially attempted , we decided to perform closed reduction and intramedullary nail fixation for femur shaft fracture . in same time , we decide to perform arthroscopic reduction and internal fixation with screws for acetabular fracture , because of early rehabilitation . under general anesthesia , femoral shaft fracture was treated by intramedullary nail system first . and , along the same way as case 1 ,
the fracture fragment of the acetabular posterior wall was visualized after hematoma evacuation ( fig .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization .
after surgery , satisfactory reduction and compression were confirmed in postoperative radiographs and ct image ( fig .
the patient was instructed to walk with partial weight - bearing with the aid of two crutches for four weeks after surgery . by three months post - operatively , he recovered full activities .
after one year , femoral shaft fracture was united , we decided to removal intramedullary nail and to perform second look arthroscopy , we were able to confirm united acetabular fracture ( fig .
the patient was treated in the supine position on a commercially available hip arthroscopy distraction .
we used a conventional anterolateral viewing portal and an anterior and posterolateral working portal and examined the joint space with a 70 arthroscope .
after a blood clot and the bloody joint fluid had been aspirated , we examined the joint space and found the fracture site .
after capsulotomy was performed through the anterior to anterolateral site , joint debridement and loose body removal were perfomed .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire .
so , this technique is not available on severe comminuted fractures that are not compressed by screws . at this time , must keep three notices in mind .
first , check the size and shape of obturator foramen in intraoperative c - arm image are not different from preoperative obturator foramen view ( fig .
9 ) . if size and shape are not same , tilt table like taking obturator foramen view
in this way , it will help to find accurate insertion site of a flexible guide wire .
second , we need a curved guide because of curved acetabular shape . if you use straight guide wire , guide wire can penetrate articular surface .
for this reason , we decided to use curved guide of jugger knot ( 1.4 and 1.5 mm , curved reusable guide ; biomet inc . ,
it can help to access easily to posterior wall of acetabulum , to maintain reduction by gently compressive force while a flexible guide wire was fixated .
so , you may make a choice among to produce long reamer , or to extend skin incision , in posterolateral portal , insert the shortest arthroscopic cannula deeply .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization .
a 38-year - old man was injured in a car accident while driving , sustaining a left acetabular posterior wall fracture ( fig .
1 ) . we explain to patient that it can be treated with non - weight bearing for 4 to 6 weeks , but he denied conservative treatment because he must return to his job .
so , we decided to perform arthroscopic reduction and screw fixation after three days from trauma . under spinal anesthesia ,
the patient was positioned supine on a fracture table with the affected limb in traction and the opposite limb .
we made three portal ( anterolateral , anterior , and posterolateral portals ) , the fracture fragment of the acetabular posterior wall was visualized after hematoma evacuation ( fig .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire through posterolateral portal .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization ( fig .
3 ) . postoperative radiographs and computed tomography ( ct ) was performed , the fragment was satisfactory reduced and compressed ( fig .
, the patient discharged after care for postoperative wound and went back to normal life with crutch .
he did not complain pain or discomfort after six months from the surgery , began heavy sports activities .
a 41-year - old man was injured in a car accident while driving , sustaining a right acetabular posterior wall fracture ( fig .
skeletal traction was initially attempted , we decided to perform closed reduction and intramedullary nail fixation for femur shaft fracture . in same time , we decide to perform arthroscopic reduction and internal fixation with screws for acetabular fracture , because of early rehabilitation . under general anesthesia ,
, along the same way as case 1 , the fracture fragment of the acetabular posterior wall was visualized after hematoma evacuation ( fig .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization .
after surgery , satisfactory reduction and compression were confirmed in postoperative radiographs and ct image ( fig .
the patient was instructed to walk with partial weight - bearing with the aid of two crutches for four weeks after surgery . by three months post - operatively , he recovered full activities .
after one year , femoral shaft fracture was united , we decided to removal intramedullary nail and to perform second look arthroscopy , we were able to confirm united acetabular fracture ( fig . 8) .
the patient was treated in the supine position on a commercially available hip arthroscopy distraction .
we used a conventional anterolateral viewing portal and an anterior and posterolateral working portal and examined the joint space with a 70 arthroscope .
after a blood clot and the bloody joint fluid had been aspirated , we examined the joint space and found the fracture site .
after capsulotomy was performed through the anterior to anterolateral site , joint debridement and loose body removal were perfomed .
the fracture fragment was reduced into the intact acetabular side using a flexible guide wire .
so , this technique is not available on severe comminuted fractures that are not compressed by screws . at this time , must keep three notices in mind .
first , check the size and shape of obturator foramen in intraoperative c - arm image are not different from preoperative obturator foramen view ( fig .
9 ) . if size and shape are not same , tilt table like taking obturator foramen view . in this way
second , we need a curved guide because of curved acetabular shape . if you use straight guide wire , guide wire can penetrate articular surface .
for this reason , we decided to use curved guide of jugger knot ( 1.4 and 1.5 mm , curved reusable guide ; biomet inc . ,
10 ) . it can help to access easily to posterior wall of acetabulum , to maintain reduction by gently compressive force while a flexible guide wire was fixated .
so , you may make a choice among to produce long reamer , or to extend skin incision , in posterolateral portal , insert the shortest arthroscopic cannula deeply .
after anatomical reduction in the fracture site was confirmed by arthroscopy , we used a 4.0-mm - diameter cannulated screws to fixate the fragment under direct arthroscopic visualization .
nonoperative treatment generally consists of bed rest and traction followed by bed - to - chair transfer .
nonoperative treatment can be used in patients with simple , undisplaced , minimally displaced and those without free fragments in the joint . the prolonged bed rest necessary for conservative treatment , however , can lead to different complications in elderly patients , including potentially life - threatening bed sores , pneumonia , and urinary infections .
elderly patients frequently have compromised strength , agility and balance , altered mental status , or neurological disorders .
these patients are unlikely to comply with nonoperative management , and risk falling or involuntarily putting excessive weight on the injured limb , resulting in secondary fracture displacement4 ) .
of course , surgery is not needed in simple acetabular fracture , but early internal fixation can help to avoid these complications in high - risk patients by simple and less - invasive surgery .
arthroscopic techniques for fixation of intra - articular fractures offer the advantage of superior visualization and reduction of the articular surface , diagnosis and treatment5 ) .
many author treated acetabular fracture with arthroscopic reduction and had a good result even in femoral head fracture and dislocation367 ) .
the additional benefits of this method were joint lavage and debridement of the hip joint .
joint debridement is known to be helpful in removing loose osteochondral fragments and might be helpful in reducing the risk of future osteoarthritis8 ) . furthermore , arthroscopic reduction techniques offer another benefit for intraarticular lesions . in case 2 ,
patient had a metallic artifact , it would be impossible to obtain magnetic resonance imaging .
so , this technique is a useful method for diagnosing and treating intraarticular lesions after hip trauma . in case 2 ,
so we worried about destruction of interlocking screw and distraction of fracture site by traction during hip arthroscopy .
there is no reference about these problems , but beutel et al.9 ) reported that in the patients with prior lower - extremity arthroplasty , the use of traction during hip arthroscopy is safe in this population .
we applied gentle traction , fracture site and interlocking screw were visualized with fluoroscopy to confirm that traction was free of complications .
although hip arthroscopy is technically more demanding , it is less invasive and can be easy way to return to normal life . however , there are concerns in relation to fluid extravasation creating compartment syndrome - type complications in the acute setting10 ) .
so , arthroscopic reduction technique will be good choice for acetabulum fracture , even in anterior or posterior column fracture , if only to overcome fluid extravasation .
we observed closely intraoperative and postoperative monitoring of abdominal distention , core body temperature , and hemodynamic stability .
high pump pressures may be risk factors , pump pressures were limited by 30 - 60 mmhg . and we tried to reduce operative time within 90 minutes . arthroscopic reduction and screw fixation technique is useful for reducing postoperative pain and achieving early return to activities for the patient .
this technique will be tried in non - displaced and non - comminuted fractures , be the cornerstone to extend its indications with developments of techniques and equipments . | acetabular fractures can be treated with variable method . in this study ,
acetabular posterior wall fracture was treated with arthroscopic reduction and fixation using cannulated screw .
the patient recovered immediately and had a satisfactory outcome . in some case of acetabular fracture
could be good indication with additional advantages of joint debridement and loose body removal .
so , we report our case with technical note . |
a major distinction between private hospitals and non - profit hospitals in the us is that the later are considered charities and are expected to provide free or low - cost medical care for marginalized individuals .
this charity care is clearly beneficial for a large number of uninsured americans and in exchange , non - profit hospitals have long been exempt from nearly all federal , state and municipal taxes ( rubin et al .
however , expansion of public health insurance in the us has made the tax - exemption of non - profit hospitals controversial . as more americans have health insurance , there are fewer instances where hospital services are uncompensated ( burke et al .
private hospital leaders and health policy makers have also suggested that modern non - profit hospitals in the us , with highly paid executives , sophisticated operations and aggressive collection practices , barely resemble the charities that once warranted tax - exemption ( rubin et al .
, the definition of cb and eligibility for tax exemption has changed over time ( see below ) . in 2010 ,
the aca introduced the requirement that non - profit hospitals could remain tax - exempt , but would have to provide cb activities based on the results of regular chnas ( singh et al .
2015 ) . where the initial accountability for cb aimed to improve access to care , the aca reform signalled recognition among health policy makers that the prevailing medical model of focusing on treatment and cure at the expense of prevention and health promotion is ineffective and unsustainable
the definition of cb has changed over time ( table 1 ) . since 1969 ,
cb was defined and reported at the state level , with most states using the internal revenue service ( irs ) definition ( rubin et al . 2015 ) .
this definition aimed to improve access , with the addition of maintaining a community - controlled board as a strategy to ensure unique community health needs were addressed . however
, the irs broadened its definition in 2007 to include community health improvement activities , research , education of health professionals and contributions to community groups that engage in cb activities ( young et al .
extend medical staff privileges to all qualified physicians in the area , consistent with the size and nature of the facility 4 .
maintain a community - controlled board ( i.e. , a governing board with membership , by appointment , primarily from the local community ) 1 .
charity care ( i.e. , subsidized care for persons who meet the criteria for charity care established by the hospital ) 2 .
unreimbursed costs for means - tested government programs ( e.g. , medicare and medicaid ) 3 . subsidized health services ( i.e. , clinical services provided at a financial loss ) 4 . community health improvement services and community - benefit operations ( i.e. , activities carried out or supported for the express purpose of improving community health , such as conducting or otherwise supporting childhood immunization efforts ) 6 .
financial and in - kind contributions to community groups ( i.e. , contributions to carry out any of the activities that are classified as community benefits ) despite its expansion , an examination of hospitals ' initial reporting using the 2007 definition found that ( 1 ) access to care represented > 86% of hospital cb activities , and ( 2 ) hospitals engaged in limited community health improvement activities ( young et al . 2013 ) .
other research demonstrated wide variation in cb spending across states , ranging from $ 30 to $ 335 per capita ( bakken and kindig 2015 ) . because the expanded definition also did not produce the desired result , the aca added the requirement that non - profit hospitals must conduct regular chnas as a condition of their federal tax - exempt status ( singh et al . 2015 ) .
the definition of cb has changed over time ( table 1 ) . since 1969 ,
cb was defined and reported at the state level , with most states using the internal revenue service ( irs ) definition ( rubin et al . 2015 ) .
this definition aimed to improve access , with the addition of maintaining a community - controlled board as a strategy to ensure unique community health needs were addressed .
however , this definition was found to be limited and ineffective ( rubin et al .
, the irs broadened its definition in 2007 to include community health improvement activities , research , education of health professionals and contributions to community groups that engage in cb activities ( young et al .
extend medical staff privileges to all qualified physicians in the area , consistent with the size and nature of the facility 4 .
maintain a community - controlled board ( i.e. , a governing board with membership , by appointment , primarily from the local community ) 1 .
charity care ( i.e. , subsidized care for persons who meet the criteria for charity care established by the hospital ) 2 .
unreimbursed costs for means - tested government programs ( e.g. , medicare and medicaid ) 3 . subsidized health services ( i.e. , clinical services provided at a financial loss ) 4 . community health improvement services and community - benefit operations ( i.e. , activities carried out or supported for the express purpose of improving community health , such as conducting or otherwise supporting childhood immunization efforts ) 6 .
financial and in - kind contributions to community groups ( i.e. , contributions to carry out any of the activities that are classified as community benefits ) despite its expansion , an examination of hospitals ' initial reporting using the 2007 definition found that ( 1 ) access to care represented > 86% of hospital cb activities , and ( 2 ) hospitals engaged in limited community health improvement activities ( young et al . 2013 ) .
other research demonstrated wide variation in cb spending across states , ranging from $ 30 to $ 335 per capita ( bakken and kindig 2015 ) . because the expanded definition also did not produce the desired result , the aca added the requirement that non - profit hospitals must conduct regular chnas as a condition of their federal tax - exempt status ( singh et al . 2015 ) .
non - profit hospitals in the us must now conduct chnas at least every three years to remain exempt from federal taxes .
each assessment must include consultations with community stakeholders and public health officials , and multi - hospital networks must conduct an assessment for each facility ( singh et al .
each hospital must develop and publish an action plan regarding how identified needs will be addressed according to the cb categories in the 2007 definition ( somerville et al .
although it is too early to tell , many report the chna requirement as a positive reform that will support hospitals to better contribute to population health improvement ( burke et al .
( 2015 : 819 ) report everyone in healthcare in the us is now working to improve population health these days . or will be very soon . or feel that they ought to be .
as reported in a special issue of this journal , ontario hospitals are currently held accountable for financial performance , service volumes , quality and patient safety ( kromm et al . 2014 ) .
these accountabilities appear to be similar for hospitals across canada , including those within rhas ( marchildon 2013 ) . while important , these accountabilities will have little effect on the upstream determinants of health ( alley et al .
given the pressing need to prevent and manage chronic diseases , as well as reduce healthcare demand in canada , numerous authors have proposed strategies for how canadian hospitals can better address community health needs ( e.g. , cohen et al . 2014 ; neudorf 2012 ) .
these include increased public health service delivery ( for hospitals within rhas ) , use of a population health lens in decision - making , and increased collaboration with non - health sector stakeholders to address upstream health determinants .
these approaches are valuable , but they rely on hospitals voluntarily directing scarce resources towards activities for which they are not held accountable and receive no compen sation .
although canadian hospitals have long seen health promotion as part of their role , hospital funding has lagged behind treatment costs and demand .
this makes it challenging for hospitals to dedicate resources towards prevention and health promotion activities ( graham et al .
in contrast , evidence indicates that external accountabilities drive internal accountabilities and activities within canadian hospitals ( kraetschmer et al .
i suggest the chna requirement and accountability for cb warrant exploration in the canadian context .
not only is hospital accountability for cb a highly studied policy intervention , it has been refined over the past half - decade in the us . in its current iteration ,
accountability for cb has also generated considerable new research and guidance that would be valuable for canadian hospitals ( e.g. , burke et al . 2014 ) .
hubs where hospitals can exchange learnings and best practices ( e.g. , http://www.communitybenefitconnect.org and http://www.cdc.gov/chinav/index.html ) .
with five modifications , chna and cb requirements could be valuable in the canadian context .
first , since all canadians have some healthcare insurance , the definition of cb should be revised to focus on specific , evidence - based prevention and health promotion activities that have the highest probability of improving community health ( rubin et al .
second , the role of population health in cb should be clarified , since cb is rarely discussed in the canadian context .
refers to hospitals ' responsibility for improving the health of those within their geographic population , not just their client populations ( see casalino et al .
third , since nearly all canadian hospitals are non - profit , chna and cb requirements should be included in existing accountability frameworks rather than being requirements for tax - exemption .
fourth , transparency should be central to this work to support accountability and knowledge - exchange ( which would be critical given the novelty of these requirements ) ( rubin et al .
fifth , as most canadian hospitals are part of rhas , it should be made explicit that ( 1 ) chna and cb requirements are for hospitals not rhas , and that ( 2 ) these requirements are an opportunity to foster collaboration between hospital leaders and public health leaders .
these are important clarifications because if rhas are held accountable , but not hospitals , experience tells us that hospitals will resume their focus on illness care , and the responsibility for chnas and cb will likely fall to public health ( moloughney 2016 ) . that said , hospitals held accountable for cb would be wise to collaborate with their local public health colleagues .
public health epidemiologists have expertise in population health assessment and likely already conduct chnas that could inform hospital planning . similarly , public health staff can assist their hospital colleagues determine where health promotion and prevention strategies could be both effective and practical .
the ultimate goal is to have chna results inform hospital planning and resource decision - making .
holding hospitals accountable for cb solidifies the importance of chnas in hospital planning , and provides justification for hospitals to allocate resources towards activities that prevent ( not just treat ) illness and injury , and reduce health inequities something that is desired , but challenging for many canadian hospital leaders in the current accountability environment .
while some canadian hospitals would embrace these requirements ( and some already have ) , clearly others would find them challenging given the resource constraints .
some hospital leaders might even echo the attitude expressed when the notion of health - promoting hospitals was first introduced : let somebody else do it ; we already have too much to do
hospitals should utilize existing chna results and collaborate with other hospitals that serve the same geographic populations .
however , where no chna has been conducted , hospital leaders should collaborate with their public health colleagues to undertake this work .
learning from the experience of 3,000 non - profit hospitals in the us , as well as related initiatives , such as the over 1,000 member hospitals of the international health - promoting hospitals network ( pelikan et al .
furthermore , early and active collaboration with researchers would be wise to ensure the chna and resultant activities produce desired outcomes .
nearly 3,000 hospitals in the us are now required to conduct chnas and are held accountable for demonstrating cb by taking action to address identified local health needs .
this is an exciting step towards improving the impact that hospitals can have on community health an idea originated in canada 30 years ago .
canadian health policy makers would be wise to examine and test a modified version of this approach . while there would be initial challenges for some hospitals , the health of the canadian population and the sustainability of our health system demand we take bold action and utilize best practices from other jurisdictions . | north american hospitals have historically struggled to engage in prevention and health promotion activities because they have not been incentivized or held accountable for doing so . however , in order to be exempt from federal taxes , 3,000 non - profit hospitals in the us must now regularly assess the health status of the communities they serve , and take action to address identified health needs .
this is called
accountability for community benefit , and it is required under the patient protection and affordable care act ( commonly known as obamacare ) . a modified version of accountability for community benefit warrants exploration in the canadian context , as it may support canadian hospitals to direct resources towards prevention and health promotion activities something many canadian hospitals want to do , but struggle with in the current accountability environment .
this is an important health policy topic because even a small shift in focus by hospitals towards prevention and health promotion has the potential to improve population health and reduce healthcare demand . |
fm and fb are coinventors on a patent application regarding a diagnostic cf - mirna signature cited herein . | micrornas ( mirnas ) are small non - coding rnas that act as master regulators of many cellular processes . the expression of mirnas is often deregulated in human tumors , causing the alteration of molecular mechanisms relevant for cancer progression .
importantly , mirnas are detectable in the blood and their quantity fluctuations are the hallmark of pathogenic conditions , including cancer .
several groups reported the identification of circulating cell - free mirnas ( cf - mirnas ) in the human serum and plasma and demonstrated their diagnostic and prognostic utility .
other studies also shown that it may be feasible to apply such cf - mirna signatures within screening programs in order to improve cancer early detection .
circulating cf - mirnas therefore appear to be excellent candidates for blood - borne cancer biomarkers . |
while it is commonly understood that multiple sclerosis ( ms ) is an autoimmune disease of multifactorial etiology , the exact mechanism of causation has not yet been elucidated .
consequently , disease - specific ms therapy has not advanced beyond the use of interferons and immunosuppressive agents , the application of which is now more than thirty - year old [ 1 , 2 ] and of questionable , long - term efficacy . based upon his early work and
the work of other investigators [ 511 ] , the author hypothesized that ms is a humoral autoimmune disease , caused by faulty interplay between myelin - specific ige , competing specific non - ige antibodies , and ige - triggered , degranulating mast cells .
affected mast cells are likely to expel proteolytic enzymes and possibly other factors which damage or destroy targeted myelin and the axons that are sheathed by it . to test the hypothesis , a mimotopic , peptide antigen - based
, serum immunoassay was developed to measure dimer - bound ige excess among ms patients , wherein the ige specifically complexes with two or more myelin surface epitopes at an interval of 40100 ngstrms , a separation critical for mast cell degranulation and tissue - damaging effect .
because ms patients often consume numerous medications , some started before observed disease onset , questions arise about the medications ' effect upon ( 1 ) disease origin , ( 2 ) serum antibody test function , and ( 3 ) hindrance of normal and protective , humoral immune processes . epitope - specific ige is but one isotype involved in the myelin inflammatory process as other investigators have also documented the presence of myelin - specific iga , igg , and igm .
concomitantly present , the differing isotypes are likely to be cross - competitive for epitopic antigens .
an analytical method was therefore developed to measure this potential competition and a determination made whether the competition exists and is likely part of the ms autoimmune process .
the analytical method entailed quantification of the ratio of myelin epitope - specific ige relative to the sum of the matching myelin - specific non - ige isotypes . in order to simplify the process ,
the non - ige antibody level was determined by measuring epitope - specific human kappa plus lambda chains and subtracting the matching epitope - specific ige . with experience
, it became obvious that the specific ige subtraction was unnecessary as the ige was exceedingly small in comparison to the matching non - ige antibodies .
individual humoral epitopes were mimicked by single peptides that were 5 amino acids in length , the size that the author had previously estimated would fit into a single antibody fab site . when analyzing surface pentameric structures of individual myelin proteins for potentially serving as humoral epitopes ( section 2 ) and comparing each structure against surface pentamers on all human genome proteins , it was noted that singular , potentially ms - associated , mimotopic peptides displayed amino acid sequences that were located on the surface of a single , specific myelin protein and on no other protein transcribed from the human genome .
the hopp and woods hydrophilicity method for locating epitopic sites on linear protein sequences was used to predict the humoral epitopes on ( a ) myelin proteolipid protein ( plp , ) ; ( b ) myelin oligodendrocyte glycoprotein ( mog , ) ; ( c ) myelin basic protein ( mbp ) isoforms 1 , 2 and 3 ; ( d ) oligodendrocyte myelin glycoprotein , ( e ) claudin 11 . in order to estimate the functional distance ( in ngstrms ) between epitopes on the surface of each myelin protein , as depicted on its hopp and woods plot ,
the average diameter of constituent amino acids was determined by ( a ) comparing the mass of each amino acid relative to the mass of alanine with its known diameter of 6.9 ngstrms ; ( b ) multiplying individual mass ratios times 6.9 ngstrms to obtain estimated amino acid diameter s for the non - alanine amino acids ; ( c ) averaging the resulting amino acid diameters to obtain a n overall average amino acid diameter of 10.6 ngstrms ( table 1 ) .
individual hopp and woods , excel x - y plots of each protein 's amino acid sequence were modified so as to only depict the protein 's hydrophilic surface , either extracellular or intracellular , as if flattened by trimming away all amino acids that were functionally hydrophobic , and likely to be located in the protein interior , but leaving 2 on each hydrophilic edge to reflect infolding toward the protein center ( figures 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ) .
the bridging distance between dimeric surface epitopes on individual myelin proteins was estimated by multiplying the intervening amino acids number by 10.6 ngstrms per amino acid . because a protein surface is not flat but oscillates in depth , sera from an age- and gender - varied ms - negative control group
were sequentially tested to measure dimer - point , myelin epitope - specific ige/(kappa + lambda ) values while reducing the estimated dimeric distances in 5 percent intervals to find a reduction percentage to use as a factorial adjustment which simulated staircase dips in normally rolling surface contours of proteins and thus afforded functionally negative test results for the controls ( no ideal dimers present )
. a 25% reduction of the linear distances attained in step 3 between dimeric epitopes afforded test - negative results for all initially tested , negative - control serum samples by exhibiting no more than one dimer point as being ige/(kappa + lambda ) test positive . in validation , when testing positive control ms patient sera and employing the 25% reduction factor , dimer bridging , test - positive values were attained whose corresponding epitopes ' separation ranged from between 40 to 100 ngstrms , thus indicating a likelihood of mast cell degranulation .
claudin 11 and oligodendrocyte myelin glycoprotein lacked ige dimer bridging sites and were , therefore , not analyzed further .
pathological dimer bridging values and locations are depicted in figures 49 for mog and figures 1015 for mbp .
a similar contour - mapping approach was not used for plp because it has but one structurally unique epitope expressed on the myelin surface , adarm ( figures 1 , 2 , 3 ) . however , plp molecules are highly prevalent on myelin and correctly spaced ( 6571 ngstrms ) between monomers so as to serve as ideal ige dimer - binding sites , notwithstanding allowance for the 25% rolling contour adjustment .
in figure 1 ,
proteolipid protein isoform 1 ( plp1 ) is displayed as a hopp and woods xy plot with eleven vertical columns .
the sixth , left - most , column displays the hydrophilic index ( hi ) of each listed amino acid .
the tenth column from the left depicts the sum - of - seven , continuous amino acids , hydrophilic index value of each amino acid derived by adding to its hydrophilic index ( hi ) the indices of the 3 amino acids that precede it plus the indices of the three amino acids that follow it .
areas that are net hydrophilic ( yellow highlighted ) are apt to be on the protein surface while those that are net hydrophobic ( uncolored ) would be on the protein edge or imbedded within the protein center
mog has been shown to be differentially expressed in various isoforms . however , for the purpose of identifying the potential array of mog humoral epitopes possible on all isoforms and the epitopes ' utility in dimer formation , analysis of mog sanger institute isomer 1 ( figures 49 ) proved sufficient .
the analysis illustrated the presence of two potential disease - functional dimer sites on the oligodendrocyte , extracellular mog portion ( figures 5 and 6 ) and two potential subsurface , intracellular dimer sites ( figures 8 and 9 ) if the latter were somehow immunosurveillance exposed by myelin surface ( oligodendrocyte surface ) disruption . by experience , accurate representation of an antibody binding site mandated exhibiting a unique pentamer flanked by an amino acid on each side .
myelin basic protein , an oligodendrocyte intracellular protein also potentially accessible by myelin surface disruption , exhibits a more complex array of potentially tar getable epitopes and dimer conditions than plp or mog .
all potential dimer sites are exhibited by a combination of myelin basic protein isoform 1 ( figures 1012 ) , isoform 2 ( figures 13 - 14 ) , and isoform 3 ( figure 15 ) .
for epitope - mapping , singularly unique protein surface regions longer than 5 amino acids were subdivided into overlapping pentamers to represent all possible - single - antibody binding sites ( i.e. , figure 10 ) .
as depicted in figure 16 , the basic ms test plate contained 14 mimotopic peptides corresponding to the myelin epitopes illustrated in figures 1through 15 . each peptide construct ( mimotopes pty , clayton , australia ) applied to the microplate wells comprised a mimotopic peptide preceded by an aminated hydrophilic linker , 8-amino-3,6-dioxaoctanoic acid2 ( amino - adooa - adooa ) .
the epsilon amino group on peptide lysine residues was blocked with a ( 4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)-3-methylbutyl ( ivdde ) group , to prevent undesirable , lateral binding when attaching peptide constructs to test plate wells via their free amide groups .
each construct was dissolved in ph 7.2 phosphate buffered saline ( pbs ) immobilization buffer ( product no . 28372 , thermo scientific , rockford , il , usa ) , at an assay optimum concentration ( table 2 ) .
100 l of each peptide construct solution was applied in quadruplicate to 96-well , amide - binding , maleic anhydride - activated , white 96- well plates ( thermo scientific , product no .
3501 ) and the construct solutions incubated at 2126 degrees c for 1824 hrs .
120 l of hsa background blocking solution ( 10 mg recombinant human serum albumin per ml immobilization buffer ) was applied per well .
the construct / blocking solutions were incubated at 2126 degrees c for 1824 hrs and plates aspirated and dried .
200 l of a 2% solution of hydrazine monohydrate ( sigma chemical company , st .
louis , mo , product no . 207942 ) in dmso ( dimethyl sulfoxide , thermo scientific product no .
20688 ) was applied per well and incubated at 2126 degrees c for 10 minutes .
250 l of phosphate buffered saline with 0.05% tween-20 ( pbst , thermo scientific product no .
plates were incubated at 2126 degrees c for 30 minutes , aspirated , washed three additional times , aspirated , and dried . after drying at 2126 degrees c for 1824 hrs in a clean , covered container ,
test plates were sealed with acetate plate sealers and stored at room temperature until needed .
individual plates were used for both specific ige and specific ( kappa + lambda ) assays .
the specific ige immunoassay entailed use of 100 ul / well of neat subject serum that had been spiked with 1 mg / ml aminated hydrophilic linker solution to neutralize potential , antilinker antibodies ( 50 l linker solution per 12 ml serum ) .
plates were sealed and incubated for 2 hours at 2126 degrees c and then washed four times with pbst ( 250 l / well followed by immediate aspiration ) .
100 l of 4 g / ml biotinylated , goat anti - human ige was applied per well .
( the anti - ige solution comprised 96 l of vector labs , burlingame , ca , product no .
ba-3040 added to 11.9 ml of conjugate diluent ( 10 mg / ml recombinant hsa in pbst + 0.25% peg 4000 ) ) .
after incubation for 2 hours at 2126 degrees c , the plates were washed and 100 ul / well of 64 ng / ml streptavidin horseradish peroxidase ( thermo scientific product no .
37074 ) was applied and the plate(s ) read 13 minutes after application using a luminoskan ascent microplate luminometer ( thermo scientific , waltham , ma , usa ) .
the linker - spiked test serum sample used in the specific ige assay was diluted 1/25,000 by ( a ) making a 1/100 dilution mixing together 100 l linker - spiked serum and 9.9 ml pbst and ( b ) spiking 11.950 hsa conjugate diluent with 48 l of the 1/100 diluted serum .
plates were filled with 100 l / well of 1/25 k diluted serum , sealed , and incubated for 2 hours at 2126 degrees c. equal volumes of vector biotinylated , goat anti - human kappa antibody ( ba-3060 ) plus biotinylated , goat anti - human lambda antibody ( ba-3070 ) were mixed together to form a 50 : 50 biotinylated anti-(kappa + lambda ) concentrate ( 500 g / ml )
. 96 l of the anti-(kappa + lambda ) concentrate was mixed with 11.9 ml of hsa conjugate diluent and 100 l of the resulting solution applied per well .
after 2-hour incubation at 2126 degrees c , plates were washed and 100 ul per well of 16 ng / ml streptavidin horseradish peroxidase solution applied .
test plates were incubated at 2126 degrees c for 30 minutes , aspirated , and washed .
100 ul / well of thermo scientific chemiluminescence substrate was applied and the plates read at 13 minutes after application . specific ige and matching specific ( kappa + lambda ) signals
average test values corresponding to individual mimotopic peptides were determined by discarding the highest and lowest of four values and averaging the remaining two .
the same procedure was followed for the four background well values , together with calculation of twice the standard deviation of the two - point average .
the blank well background was deemed to be its average value plus twice the standard deviation .
the plate blank well value was subtracted from each peptide - coated well average to yield a net signal .
kappa + lambda values were multiplied by 25,000 in order to delineate the corresponding neat serum ( undiluted ) epitope - specific kappa + lambda antibody levels .
ige/(k+l ) values were multiplied by 1,000,000 in order to bring each quotient to a positive number if attainable .
test results with negative values or values of less than 0.5 were assumed to be test negative .
disease - positive and disease - negative ( control ) sera were purchased from bioserve ( beltsville , md , usa ) .
multiple sclerosis - positive samples were from patients who had not yet received ms - specific therapy , patients who were taking interferon and/or copaxone ( glatiramer acetate ) with or without medication shown to be immunosuppressive ( tables 3(a)3(e ) ) , and patients who were only being treated with immunosuppressive substances .
female ( n = 10 ) nor male ( n = 10 ) age - varied , control serum samples were ms test positive by exhibiting ige/(kappa + lambda ) dimer - positive results . being positive , the control sera would have been ige/(kappa + lambda ) positive when tested against the plp adarm peptide antigen ( figures 13 ) and/or the non - plp peptides listed on the left - most column of table 4 that were properly dimer paired .
five ms patients who had not taken copaxone , beta interferons , or immunosuppressive agents were ms test positive ( figure 19 ) .
of the latter group , all three were myelin surface positive and two patients were also positive against subsurface mog epitopes ( positives are highlighted in yellow ) .
all three patients were dimer positive against the sole plp epitope , adarm , irrespective of whether each had relapsing remitting ( rr ) , secondary progressive ( sp ) , or primary progressive ( pp ) ms .
( potentially immunosuppressive , ancillary agents are numerically identified in yellow at the bottom of the figure and referenced in table 3 . )
four of fourteen test subjects were plp ige dimer test positive , irrespective of disease classification .
( immunosuppressive agents are identified in yellow at the bottom of the figure and referenced in table 3 . )
( immunosuppressive agents are identified in yellow at the bottom of the figure and referenced in table 3 . )
the test data is both an affirmation and a significant challenge to the theories and work of other investigators .
it affirms the premise that ms is a humoral autoimmune disease as validated by clinicians who have worked with natalizumab ( tysabri ) , a humanized monoclonal antibody whose therapeutic use results in a systemic increase in b lymphocytes and , ultimately , plasma cells and specific serum autoantibodies [ 5254 ] .
where it differs is in affording a precise explanation of the multilayered humoral ms process and how it might be remedied .
we have concluded that multiple sclerosis is a complex , humoral autoimmune disease caused by ige dimer formation on the surface or immediate subsurface of cns myelin that results in focal mast cell degranulation .
the degranulating mast cells likely release proteolytic enzymes and possibly other factors that damage or destroy proximal neurons .
test results of ms patients taking medication shown to have an immunosuppressive effect suggest either interference with the ige / competing antibody pathological process or with the ms test itself .
this was inferred by the quantitative difference in ms test scores between the patients who were taking no medication and exhibited relatively high test scores , patients who were being treated with a single ms - specific pharmaceutical ( beta interferon or copaxone ) , but had relatively low positive test scores , and patients who were taking the described immunosuppressive agents , with or without interferon or copaxone , and were only sporadically ms test positive .
this suggests that the conventional , multiple therapy approach may potentially hinder therapeutic efficacy by altering normal immune function . as interferon and copaxone
are prescribed because of their ms - specific , immunosuppressive , effect and ms is likely an autoimmune disease , it is reasonable to expect some decrease in humoral immune function among specifically treated patients , as reflected by the low anti - plp test scores exhibited in figure 20 .
however , the test scores of ms patients who were also receiving ancillary substances that have been shown to be immunosuppressive ( figures 2123 ) , infer that augmentation of immune suppression may not always be therapeutically beneficial .
another possibility is that the ms - specific and ancillary pharmaceuticals may also hinder serum immunoassay function making some or all specific immunoassays diagnostically unreliable .
also suggested is the possibility that ( 1 ) the ancillary medications , having only been in use since the early twentieth century , may have historically played an instigating or promoting role in ms causation and/or progression through disruption of homeostatic , immune system controls .
the absence of ms test - positive results against mbp dimers may have been due to their deep , intracellular location and relative freedom from immune surveillance and pathological action .
it may also indicate that ( a ) successful mbp humoral targeting first calls for myelin surface disruption via action against plp and/or outer mog in order to provide penetrating access for anti - mbp antibodies and/or lymphocytes ; ( b ) mbp is an autoimmune target , but of lesser frequency or importance than the epitopes on the outer surface or immediate sub - surface of myelin .
if ms proves to be an ige dimer - driven , humoral autoimmune disease , as is suggested by the test data , treatment with mimotopic peptides homologous to those used in the diagnostic immunoassay might prove to be therapeutically beneficial by neutralizing anti - myelin ige antibodies .
the therapeutic peptides would need to be administered in such a way as to insure intravascular delivery of quantities sufficient to neutralize all epitope - specific dimeric ige autoantibodies through antibody - to - peptide complexing or by neutralizing key epitope - specific ige antibodies whose target epitopes are cornerstones of a number of pathological dimers .
the elimination of one or two dimer - point - specific autoantibodies could prevent multi - site - initiated mast cell degranulation and halt the pathological autoimmune process .
cornerstone dimer - blocking peptides are highlighted in bold within the full array of potentially therapeutic peptides listed in the sixth column from the left of table 4 and whose corresponding epitopes and dimers are illustrated in figures 4thru 15 . to be effective , therapeutic peptides would need to ( a ) possess an exact structural match with the specific myelin protein epitope ; ( b ) be of sufficient length ( 5 - 6 amino acids ) to easily fit and be avidly bound by a single autoantibody ; ( c ) be relatively hydrophilic so as to be functionally soluble when injected or ingested ; ( d ) if ingested , be aided in enteric absorption by pharmaceutical agents such as medium - chain fatty acid constructs , superporous hydrogels , or n - trimethyl chitosan chloride .
evidence is presented that multiple sclerosis is a humoral autoimmune disease caused by ige dimer formation on the surface or immediate subsurface of cns myelin that results in focal mast cell degranulation with release of tissue - damaging enzymes and/or other substances . | the author hypothesized that multiple sclerosis ( ms ) is a humoral autoimmune disease , caused by faulty interplay between myelin - specific , dimeric ige , specifically competing non - ige antibodies and ige - triggered degranulating mast cells .
the principal fault was believed to be insufficient quantity of protective , specific non - ige antibodies .
also conjectured was the possibility of an unexpected and adverse immune suppression caused by none - ms pharmaceuticals being consumed by patients for their ms or for other conditions . to test both hypotheses , a mimotopic , peptide antigen - based , serum immunoassay was developed to measure dimer - bound ige excess among ms patients , wherein the ige specifically complexes with two or more myelin surface epitopes at an interval of 40100 angstroms , a separation critical for mast cell degranulation and cell damaging effect .
ms test sensitivity and specificity , when analyzing five previously untreated patients for dimeric ige presence , was 100% . in direct comparison ,
twenty age- and gender - matched female and male control subjects were test negative .
analysis of 35 multiple sclerosis patients , who were concomitantly being treated with potentially immunosuppressive pharmaceuticals , appeared to show the substances ' negative effect upon ms causation , progression , or specific immunoassay performance .
therefore , ms is likely an autoimmune disease caused by ige - mediated mast cell degranulation possibly in conjunction with immunosuppressive agents . |
there have been many approaches to segmentation in medical imaging , including both the active shape methods pioneered by kass et al . and template based approaches pioneered by dann et al .
for studying images made up of simple homogeneous structures such as anatomical structures , local active evolution methods [ 1 , 35 ] which are encoded through their boundary representations are natural . in such methods ,
the complexity of the representation is reduced from an encoding based on the dimension of the extrinsic background space containing the object , to the dimension of the boundary . given the line of work in template based computational anatomy which has emphasized the important role of diffeomorphisms for defining bijective correspondence between coordinate systems , it is natural to constrain the iterative methods of active shapes so that shape evolution preserves the original topology of the template .
this is the intention of the diffeomorphic active contour ( dac ) approaches taken by younes et al .
dac methods , in a form similar to the original methods of christensen et al . and
trouv [ 9 , 10 ] , only optimize for the final position of the deformable template and not for the evolution process that leads to it .
the approach adopted herein results in an entire trajectory through shape space , allowing basic prior knowledge , that is , proximity to a template , to be incorporated in the estimate of a shape .
the trajectories considered are geodesic flows , which are deduced from the riemannian structure associated to large deformation diffeomorphic metric mapping ( lddmm ) [ 1012 ] .
geodesics are characterized by a conservation law [ 7 , 1316 ] on the momentum associated to the evolution , where we describe in section 2 what is meant by momentum in this context .
this allows a further reduction in complexity from a time varying flow to a single initial condition : an initial momentum vector . in other words ,
a target shape is represented as the endpoint of a geodesic flow from a template and can be encoded by one such vector . in this
setting , knowledge of shape variability is straightforwardly incorporated via prior distributions on initial momentum .
we call these connections geodesically controlled diffeomorphic active shapes ( gdas ) . in this paper
the gdas method allows us to introduce prior distributions so as to support the diffeomorphic large deformations of unconstrained lddmm ( taking advantage of the reduction in complexity from a time varying flow to an initial condition ) , while at the same time constraining the mapping , so it is indexed to neuroanatomical shapes such as the subcortical structures ( taking advantage of the reduction in complexity from background space to structure boundaries ) .
we demonstrate that these mappings are robust to small variations associated with the mri measures of the structures .
this is accomplished by constraining the initial momentum of the gdas solutions to be in the span of a finite - dimensional basis constructed from pca associated with large - scale surface - based anatomical studies and by penalizing our initial momentum estimates in basis directions of low variability as recently also derived in qiu et al .
's work . as with the classical active shape methods ( described for example in [ 1925 ] , we pose the gdas problem in the variational setting with the data term used for matching derived from various representations of a partition of the scenes including ( i ) collection of structures defined via triangulated meshes , ( ii ) a collection of structures defined through feature points , and ( iii ) a collection of homogeneous structures defined via inside - outside appearance model [ 2630 ] . in case ( iii ) , the process is iteratively driven by a voxel 's likelihood of being interior or exterior of the region of interest ( roi ) , with the shape controlled by the conservation law geodesic dynamics . in our model ,
the appearance likelihood at each voxel only depends on whether the voxel is inside or outside the surface .
it is estimated from the mri training samples and modelled as gaussian mixtures [ 31 , 32 ] learned with the expectation maximization algorithm .
first proposed this framework in a discussion of statistics on diffeomorphisms , and more recently qiu et al
. addressed this problem and derived an algorithm for the case of surface - to - surface matching . here , we consider a general data attachment term and provide a variational solution .
we develop and implement a gradient descent algorithm for the case of surface matching , landmark matching , and grayscale image segmentation .
a lack of robustness is an important challenge to high dimensional registration and a barrier to its automation and use in high throughput studies .
we show that gdas provides an efficient method for constraining lddmm to incorporate the finite - dimensionality of typical shape variation and emphasize the robust performance of our methods on challenging biological datasets
in our region - of - interest ( roi ) approaches to subcortical structure analysis in the human brain , our goal is to robustly segment anatomical structures ( in particular neuroanatomical structures such as the hippocampus , caudate nucleus , etc . ) from the surrounding environment using a given set of data ( such as manually placed landmarks within an roi , coarse segmentations , or mr images ) .
typically , anatomical structures have their own characteristic shapes and appearance which must be learned from training data to successfully perform segmentation .
the methodology of tangent space representation has been a powerful tool in computational anatomy , since it was proposed in . in this context ,
evolution of visual structures , like points , curves , surfaces , and images is governed by geodesic equations . by the law of momentum conservation ,
the initial state of the equations determines the entire trajectory of evolution and can be used as a representation of the trajectory endpoint .
we refer to [ 16 , 34 ] for more details and context in shape spaces modeled as homogeneous spaces under diffeomorphic action and describe here a special form of the associated equations that will be adapted to our needs . for a triangulated surface s0 in with vertices x1 , , xl , the initial momentum (0 ) : s0
can be represented by a vector al at each vertex through (0 ) = l=1al(xl ) .
one can derive the geodesic equation for the evolution of s0 , which is equivalent to the geodesic equation for point sets .
we define a radially symmetric smoothing kernel k on . a typical choice , used here , is
( 1)k(x , y)=exp(||xy||222 ) .
with k(x , y ) = (||x
y|| ) , we denote kl = (||xk xl|| ) , and kl = (||xk xl|| ) .
the geodesic evolution satisfies
( 2)dxkdt=l=1lklal , dakdt=2l=1lkl(alak)(xkxl ) ,
where the notation a b refers to the usual dot product between vectors in . once the initial position of the vertices , x(0 ) = ( x1(0 ) , , xl(0 ) ) , and the initial momentum vector , (0 ) = ( a1(0 ) , ,
al(0 ) ) , are provided , the evolution of the point set is uniquely determined .
the endpoints of the evolution x(1 ) = ( x1(1 ) , x2(1 ) , , xl(1 ) ) correspond to the deformed surface s(1 ) .
equation ( 2 ) induces a diffeomorphism , , that interpolates the evolution of the vertices via the equation
( 3)ddt(t , x)=l=1lk((t , x),xl)al .
the conservation law associated to ( 2 ) then takes the form al(t ) = d(t , xl)al(0 ) .
hence , we are able to represent a shape by an initial momentum vector ( as opposed to a function or distribution ) and a template . furthermore , the variability of shapes can be described from probabilistic properties of initial momentum .
clearly , as the discretization of the surface gets fine , the dimension of the control point representation of the momentum goes to infinity .
we want to characterize the main modes of statistical variations in our data , of which there is a small number up to some acceptable error .
this enables us to write the momentum vector in a finite dimensional span regardless of the discretization .
pca depends on the definition of an inner product in the considered space . in our context
, the inner product derives from the riemannian metric that led to the geodesic equation .
we calculate a population template t using the approach in , but several other algorithms are available [ 3638 ] .
we denote the inner product between two initial momentum vectors and ~ , as ,~t .
assume we have recovered mean initial momentum vector - , d orthonormal prinicipal components ui ( with ui , ujt = ij ) , and an estimate of variance along each component i .
we note that any initial momentum vector can be projected onto the principal space as
( 4)proj()=+i=1dkiui , where ki=,uit .
by parameterizing our deformations with respect to the ki ,
the variability of the surface shape is constrained by the principal space generated from the training set .
the energy includes two terms : one term is to constrain the shape in the principal space , with appropriate weights derived from pca , and the other term regulates the error of mismatch , which we will define in a general sense here and show specific examples in sections 3.2to 3.4 .
let t denote the template , which will be assumed to be a closed surface .
after learning , the selected principal space of initial momentum is spanned by d orthonormal vectors u1 , u2 , , ud corresponding to decreasing eigenvalues 1 , 2 , , d .
our goal is to segment the region - of - interest ( roi ) from using a deformable model ; that is , we want to deform the template t , so that it overlaps with the boundary of the roi .
we assume that t is a triangulated surface , with vertex set x = ( x1 , , xl ) . for an initial momentum
, we let x denote the solution at time t = 1 of ( 2 ) initialized with xk(0 ) = xk and ak(0 ) = . we let s denote the triangulated surface that inherits the topology of t with displaced vertices x. we now describe the two terms in our energy that balance the prior knowledge we have of the diffeomorphic deformation with the accuracy of the segmentation . the initial momentum is constrained to the principal space and takes the form ( 0)=-+n=1dknun . this prior knowledge is regulated by the coefficients of principal components , scaled by eigenvalues , resulting in the first term of our cost function :
( 5)e1=n=1dkn2n . we define the accuracy of segmentation based on some function e2 of only available data ( e.g. , an image , a set of landmarks , or a surface ) and the configuration of our deformed template s. for the time being , we assume that the derivative of this function with respect to each of the xi is known , and we denote the vector of this derivative by e2/x . our goal is to find the optimal coefficients k1 , k2 , , kd that minimize the energy :
( 6)e = e1 + 12e2 .
the variational problem is solved by calculating the derivative of e with respect to each coefficient kn .
the derivative of e2 can be calculated by the chain rule
( 8)e2kn=(e2x)t(x)un=(e2)tun .
while the term x/ is unknown , its product with e2/x ( which we denote as e2/ ) can be calculated numerically by solving a system of linear ordinary differential equations .
this adjoint method has become common in this context and is derived , for example , in .
it is described for completeness in appendix b. the derivative of e is given by
( 9)ekn=2knn+12(e2)tun .
we now discuss three applications and explain examples of e2 and their gradients . in challenging surface mapping applications , it can be necessary to regularize the mappings to avoid undesirable results , and gdas provides a powerful method for doing so . in particular , volumetric segmentations of neuroanatomy
converting them to an isosurface for analysis and display is standard , and gdas provides a method to convert such an isosurface to one reflecting the typicality and variability of a population , rather than features of the volumetric data with an unnatural voxelized structure .
we retain it here as it is the most natural application of gdas ( priors learned from surface matching are used to regularize surface matching ) , to develop a notation consistent with that for our other applications and to demonstrate robust performance on poorly behaved datasets .
the deformed template surface s is triangulated with vertices x1 , , xl . suppose the template surface has m faces denoted as f = ( f1 , , fm ) .
each face is represented by an ordered triple of vertices : f = ( xf,1 , xf,2 , xf,3 ) .
we define oriented edges on face f by
( 10)ef,1=xf,2xf,3,ef,2=xf,3xf,1,ef,3=xf,1xf,2 ,
the area - weighted normal to face f by
( 11)nf=12ef,3ef,2 ,
and the face center by
( 12)cf=13(xf,1+xf,2+xf,3 ) . similarly ,
, fm ) , with oriented edges ef,1 , ef,2 , ef,3 , area - weighted normals given by nf , and face center cf. similarly to the case for velocity fields , we define a smoothing kernel ks ( s for surface ) of the form in ( 1 ) to be used for comparing two surfaces . following , we embed surface matching in a more general current matching problem .
this results in an energy to be minimized taking into account closeness between two surfaces , as well as orientation of normals :
( 13)e2=i=1m j=1mnitks(ci,cj)nj 2i=1m j=1mnitks(ci,cj)nj + i=1m j=1mnitks(ci,cj)nj.
the constant in ( 6 ) is determined heuristically .
we refer the reader to for the derivation of this energy gradient and present the result only here :
( 14)e2x|k=f : xk=xf , i[j=1mef , iks(cj,cf)nj + 23(nftcfks(cj,cf))nj j=1mef , iks(cj,cf)nj 23(nftcfks(cj,cf))nj ] ,
where the first sum is over faces f for which xk is a vertex , and the symbol i is reserved for the index of that vertex on each such face ( i { 1,2 , 3 } )
. a further application of our framework involves roi analysis methods based on diffeomorphic landmark matching .
given a template surface containing k landmarks located on vertices , a trained technician places corresponding landmarks in t1 mr images .
diffeomorphic landmark matching provides a segmentation of the structure of interest in each t1 image by applying the landmark - based transformation to the entire template surface .
this procedure is advantageous , because it provides a compromise between the speed of automatic segmentation and the accuracy of hand segmentation .
however , variability in landmark placement and sparsity of landmarks can occasionally lead to unsatisfactory segmentation results and to a time - consuming quality control stage where such segmentations are fixed manually .
we propose to regularize the problem , taking into account landmark placement variability based on voxel size , as well as shape variability learned from pca . for simplicity , we assume that landmarks on the template are chosen among the vertices of its representation as a triangulated surface .
we denote by xi(t ) = xl(i)(t ) the ith landmark , which is placed on a template vertex l(i ) and flowed according to ( 2 ) up to time t. therefore , xi(1 ) = xl(i ) .
we assume that the only available information on the targets is landmarks at positions homologous to those on the template .
the accuracy of segmentation is then based on the squared distance between deformed template and target landmarks , leading to the term
( 15)e2=i=1k||xi(1)yi||2 .
the weighting parameter is chosen on the order of voxel size = ( ( x/2 ) + ( y/2 ) + ( z/2))/3 ( equal to 0.4475 for our application ) where x , y , and z are the target image 's voxel dimension .
the variation of e2 with respect to the kth deformed template vertex is 0 if this vertex does not correspond to a landmark , and 2(xk yk ) = 2(xl(k )
yk ) if it does . that is ,
( 16)e2x|k={0k is not a landmark,2(xkyj)k is the jth landmark .
, we assume that such structures are relatively homogenous throughout and therefore chose an appearance model for voxel intensities that depend on location only through whether they are inside the structure or not . to perform image segmentation , we seek to partition the space into high integrated voxel - likelihood under such an inside - outside model .
the approach can be generalized to more complex appearance models ( involving higher order image features , e.g. ) in a straightforward way .
that is , a p.d.f of intensity i at a certain location in the tissue is in the form of
( 17)p(i;x)=q=1qq(x)12q2(x)exp((iq(x))22q2(x ) ) ,
where q , q , and q denote the weight , mean and variance of qth ( out of q ) gaussian component , respectively . in our work , we assume that the intensities at all points of the interior region ( resp .
, exterior region ) of the surfaces share the same mixed gaussian distribution and the p.d.f 's are denoted as pint and pext , respectively . given the number of mixture components , the maximum likelihood estimator for the parameters can be computed using the em algorithm .
our estimation of pint and pext ( using mixtures of gaussians ) is performed on the basis of training images with manual segmentation , in which the collection of all intensity values of voxels inside ( resp . , outside ) the roi are used for pint ( resp . ,
we define the accuracy of segmentation using integrals of likelihood of being misclassified , and we define the mismatch :
( 18)e2=xint(s)log(pext(i(x)))dx + xext(s)log(pint(i(x)))dx ,
where we denote the interior and exterior of a closed surface s by int(s ) and ext(s ) , respectively . the constant in ( 6 ) is determined heuristically .
the energy gradient is derived in theorem a.1 in appendix a. with g(y ) = log [ pext(y)/pint(i(y ) ) ] and mf , i the midpoint of the ith edge of face f , we have
( 19)e2x|k=f : xk=xf , i12|nf|fg(y)(mf , iy)ef , i df .
we use gradient descent to optimize the pca coefficients and iteratively update kn with kn (e/kn ) until convergence .
the discretization of the surface integrals in ( 19 ) is simply performed by replacing g(y)(mf , i y ) ef , i by its value at y = cf , the center of face f , with
( 20)12(mk , fcf)ek , f=13nf.
this yields the approximation
( 21)e2x|k=13f : xkfg(cf)nf ,
that has been used in our implementation .
to demonstrate the proposed algorithm , for each of the three data attachment terms , we use data being processed as part of many of our region - of - interest ( roi ) biological studies in schizophrenia , depression , alzheimer 's disease , adhd , and autism [ 4045 ] ( for landmark matching and image segmentation ) and alzheimer 's disease neuroimaging initiative ( adni ) study ( for surface matching and pca training ) . shown in the accompanying figures are 5 examples demonstrating the robustness constraints imposed by performing large deformation mapping in the span of the first few pca dimensions learned from our empirical mappings . for the case of landmark matching , we have integrated it into the workflow of several large neuroanatomical studies ( e.g. , ) .
we therefore include this application as a case study , quantifying performance in detail and demonstrating improvement we expect to gain .
our hypothesis when beginning this work was that the gdas algorithm would exhibit increased robustness compared to more standard methods , without significantly sacrificing accuracy .
data used in the preparation of this paper were obtained from the adni database ( http://adni.loni.ucla.edu/ ) .
the adni was launched in 2003 by the national institute on aging ( nia ) , the national institute of biomedical imaging and bioengineering ( nibib ) , the food and drug administration ( fda ) , private pharmaceutical companies , and nonprofit organizations , as a $ 60-million , 5-year public - private partnership .
the primary goal of adni has been to test whether serial magnetic resonance imaging ( mri ) , positron emission tomography ( pet ) , other biological markers , and clinical and neuropsychological assessment can be combined to measure the progression of mild cognitive impairment ( mci ) and early alzheimer 's disease ( ad ) .
determination of sensitive and specific markers of very early ad progression is intended to aid researchers and clinicians to develop new treatments and monitor their effectiveness , as well as lessen the time and cost of clinical trials .
the principal investigator of this initiative is michael w. weiner , md , va medical center and university of california san francisco , ca , usa .
adni is the result of efforts of many coinvestigators from a broad range of academic institutions and private corporations , and subjects have been recruited from over 50 sites across the us and canada .
the initial goal of adni was to recruit 800 adults , ages 55 to 90 , to participate in the research , approximately 200 cognitively normal older individuals to be followed for 3 years , 400 people with mci to be followed for 3 years , and 200 people with early ad to be followed for 2 years . for up - to - date information ,
see http://www.adni - info.org/. given a template and a set of target surfaces ( 650 for the adni study ) , we perform principal component analysis on initial momentum data as described in section 2.2 .
the same adni template and pca model will be used in each of our applications , even for data taken from other datasets .
we plot the variance as a function of number of dimensions and identify the number of dimensions required to account for 95% of the variance . as part of the adni study ,
volumetric parcellations ( performed using freesurfer , described , e.g. , in ) of whole brains are available at a series of time points .
the t = 0 data has been studied and a template ( see figure 1(a ) ) as well as a population of initial momenta data has been calculated . to study their changing shapes over time , we wish to convert such binary segmentations to surfaces .
however , the voxelized nature of the segmentations makes simple isosurfaces unacceptable ( as shown in figure 1(b ) ) .
we therefore employ the technique of matching our template to such an isosurface , using the constraints of a smooth deformation regularized by pca to avoid the unnatural appearance of the isosurface .
we show example results from our gdas surface matching algorithm , and compare them to typical results from the traditional surface matching lddmm algorithm .
our segmentation pipeline for our roi methods is described in [ 4044 , 46 ] .
the relevant portion ( the landmark matching phase ) for one such study is summarized here .
thirty - eight landmarks are placed along the left and right hippocampi in 441 0.93 0.93 2.0 mm t1 images of the brain .
the first was placed at the tip of the head of the hippocampus ( the center of the most anterior slice containing the hippocampus in a t1 image ) , and the second was placed at the tip of the tail of the hippocampus ( the center of the most posterior slice containing the hippocampus ) .
the distance between these two was then divided into 9 slices from anterior to posterior , and on each slice 4 landmarks were placed at the superior , inferior , medial , and lateral margins of the hippocampus .
this manual procedure takes approximately 10 minutes for a trained technician to complete , as compared to over 2 hours for a full hand segmentation of images of this size . in the existing segmentation and analysis pipeline ,
a template surface was chosen as the left hippocampus for a single subject , and a manual segmentation and resulting isosurface were generated for this case .
after a similitude alignment ( including reflecting right hippocampi to match left ) landmark lddmm was used to map this template to each target , defining a segmentation surface and binary image for each patient .
however , this procedure was found to suffer from lack of robustness , and roughly 30 out of 441 cases were unacceptable .
a laborious phase of quality control was necessary involving identifying problematic or distorted segmentations , manually editing their binary images , and regenerating isosurfaces . to measure whether our prior model provides enough robustness to avoid such issues , we chose 5 challenging cases of left hippocampi ( as identified during quality control inspection ) , where manual intervention was required and 11 typical cases , and we examined the performance improvement using the proposed algorithm rather than that outlined above .
these cases were manually segmented by a trained technician to provide a gold standard , and associated isosurfaces were generated for further evaluation .
furthermore , for 3 cases requiring intervention and 2 typical cases ( those illustrated in figure 4 ) , a second manual segmentation was obtained to give a sense of interrater variability .
note that the segmentations that are shown here do not constitute the final output of the roi pipeline described in , in which they would be further processed .
that is , the results of standard landmark mapping shown here are not reflective of the final segmentations .
the template with its associated landmarks is shown in figure 1(a ) . in figure 1(c ) , an example isosurface generated from a manual segmentation is shown together with its associated landmarks .
note that landmarks were placed on template surface vertices , but the target landmarks were placed independently ( by a different technician ) from the gold standard manual segmentation .
figure 1 shows the uncertainty of landmark placement , particularly in the region of the hippocampus ' head and demonstrates the need to include landmark placement variability in the segmentation algorithm . in these figures and throughout this paper , the color cyan will be used for the template , red for the target , blue for our new results , and green for results using existing algorithms .
to demonstrate the capabilities of the gdas image segmentation algorithm , 5 examples for the same dataset as the landmark matching study are shown .
we anticipate that good initial alignment will be important for high quality segmentations , and so the same landmark based similitude registration as above will be used to initialize the target data in this study .
the mixture model is trained based on gold standard segmentations from the remaining cases in a leave - one - out fashion .
a histogram equalization intensity transformation is applied to each t1 image to match the first training sample , based on data from a neighborhood ( 5 voxels ) around the landmarks , before estimating mixture model coefficients .
a similar histogram equalization is applied to the target image ( to match the first training sample ) before beginning the segmentation process . in analyzing results ,
first , the accuracy of gdas is comparable to existing methods , and second its robustness is improved .
second , scores are used to compare our results to gold standard segmentations . this score is defined by
( 22)=pagreeprandom1prandom ,
where pagree is the fraction of voxels in which the given segmentation agrees with the manual segmentation , and prandom is the fraction you would expect by random chance ( based only on the volumes of foreground and background ) . we calculate scores using a monte - carlo method , generating uniformly distributed points and checking if they are inside one or both segmentations . for applications involving subcortical structures ,
third , surface - to - surface distance cumulative distribution functions ( c.d.f.s ) are used to quantify average proximity of surfaces . at each vertex on each surface , we calculate the distance to the nearest vertex on the other surface and analyze the distribution of these distances .
we examine entire c.d.f.s and also examine thresholds : distance at which 50% of vertices are closer than and distance at which 80% of vertices are closer than .
robustness is also demonstrated using visual inspection , with care taken to highlight challenging regions .
surface - to - surface distance histograms are also restricted to such regions , highlighting challenging areas rather than averaging over the entire surface .
additionally , we quantify surface smoothness by measuring integrated sum of squares of principal curvatures over the deformed template surface ( this quantity is scale invariant ) ; the assumption being that smoother surfaces more accurately reflect natural anatomy in these applications .
further , to overcome limitations surrounding the accuracy of manual segmentation and to emphasize the robustness of our algorithm , we evaluate its performance on simulated data .
five hippocampal shapes are generated according to the pca model in section 4.1 , and landmarks are placed on the vertices shown in figure 1(a ) with additive gaussian noise of variance 0.01 , 0.1 , 1 , 10 , and 100 times that of the weighting parameter discussed in section 3.3.2 .
traditional lddmm landmark matching as well as gdas is run on this dataset using the same parameters as for our real data , emulating a scenario where errors in landmark placement are unknown beforehand .
we demonstrate robustness by reporting scores as a function of landmark noise for both algorithms .
lastly , we show the accuracy at which pca coefficients are recovered using mahalanobis distance , and p values corresponding to such distances are shown for real and simulated data .
after performing tangent space pca with the left hippocampus for the adni dataset , we found 31 dimensions characterized 95% of the variability for this population ( to be contrasted with 1184 3 dimensions associated with a momentum vector at each vertex of the discretized surface ) .
the outcomes of traditional lddmm surface matching and gdas surface matching are shown in figure 3 , with target isosurfaces shown on the right - hand side .
qualitatively speaking , the traditional lddmm result tends to produce squared off hippocampal heads ( left side in figure ) due to outlier voxels , as well as an overestimation of the medial margin ( bottom of figure ) due to overfitting an outlier ribbon of voxels .
the constraints imposed in gdas surface matching result in a useful and accurate segmentation reflective of the population being analyzed .
the fingerlike and ribbonlike projections reflecting the voxelized structure of the target isosurface , as well as the set of constraints used in freesurfer that are designed for an unrelated application , do not significantly influence the resulting surface . for 3 cases requiring quality control and 2 typical cases ,
traditional landmark matching is shown on the left side ( green ) , while gdas landmark matching is shown in the center column ( blue ) . in the right - hand column ,
the surfaces are shown overlaid on a t1 image , with the gold standard segmentation shown in red .
large distortions at the head of the hippocampus are common where landmark placement can be quite variable . along the length of the hippocampus , deformations with scale characteristic of the distance between landmarking planes are easily seen .
the gdas algorithm avoids each of these pitfalls , avoiding overfitting landmarks while maintaining shape variability characteristic of the population .
because poor performance of traditional landmark lddmm motivated this analysis , we also display ( in less detail ) results for an additional 8 patients selected randomly from among those identified as performing poorly .
these are shown in figure 5 with traditional lddmm results shown in the left column and gdas results shown in the right column .
it is evident that the distortions seen in the top three rows of figure 4 are typical for this dataset , and that the gdas results avoid these distortions in a similar manner .
an example of the results of gaussian mixture modeling is shown as probability density functions in figure 7 .
measured data ( after histogram equalization ) is shown as a solid curve , and the results of mixture modeling as dashed curve .
inside region ( narrow curve , blue and red ) is a unimodal distribution describing subcortical gray matter .
the challenge of this application can be seen from the outside region ( broad curve , green and magenta ) , which is a more heterogenous mixture .
it describes cerebrospinal fluid and white matter , as well as cortical gray matter and partial - volume voxels whose intensities are quite similar to the inside .
the performance appears satisfactory , an achievement considering the large overlap between inside and outside histograms seen in figure 7 .
the pca prior can prevent the template surface from deforming to erroneously include cortical gray matter in many cases , even though it is similar or identical in intensity to subcortical gray matter .
this simple inside / outside model could likely be improved , for example , by including a heterogenous appearance model , or combining landmarks and intensity information in cost functions .
the purpose of this section was to demonstrate the extensibility of the gdas framework to a varied range of applications . for the landmark matching application
, we describe in detail the performance of the gdas algorithm as compared to our existing method .
the overlap on a large scale is quantified by scores , as shown in figure 8 for each of the 16 test cases .
the gdas results tend to be similar , but better on average than those for landmark lddmm . for typical landmark matching ,
the mean and standard deviation of is 0.7131 0.0457 , and for gdas landmark matching , it is 0.7268 0.0531 .
the difference is statistically significant ( p < 0.05 in student 's paired t - test ) . for those cases with two raters ,
we examine the second score , which differed from the first by 2.66% on average , to understand interrater variability .
we present scores , averaged over the two raters in table 1 . in each case
, the gdas method performs superiorly for both raters , and this is reflected in the increased average scores from 0.732 to 0.751 . despite this improvement , it is interesting to note that the overlap between the two manual segmentations is comparable to that between the results of the two segmentation methods .
examining overlap voxel by voxel , as in figure 8 , shows our algorithm making a small improvement in accuracy .
however , the relatively larger improvement in robustness can be seen when examining surface shapes globally such as in figures 4 and 5 and contrasting with expectations from knowledge of neuroanatomy .
the region around the head was seen to be particularly challenging to segment in the traditional landmark case , and distortions occurring at the scale of landmark spacing give the impression that certain regions are left behind . to quantify accuracy globally , while acknowledging these specifically challenging areas , we use surface - to - surface - distance histograms and associated c.d.f.s . these c.d.f.s are shown for all 16 patients ( unsaturated colors , green : standard landmark matching , blue : gdas ) in figure 9(a ) . combining all vertices
a cdf closer to the top left reflects a better segmentation . in figure 9(b ) , we show the same analysis , but restricted to vertices within 10 mm of the head landmark .
this analysis was repeated ( not shown ) with vertices restricted to those within 2.5 mm of any landmark , and those not within 2.5 mm of any landmark . for each patient ,
the 50% and 80% crossings were measured and are plotted in figure 9(c ) . in each set of four bars ,
a smaller value indicates a better segmentation , but the 50% crossing indicates a typical
our hypothesis was that the gdas algorithm would show improvement in outlier regions , at the cost of poorer performance in typical regions .
this is likely due to traditional lddmm overfitting landmark placement inaccuracies , while gdas finds an appropriate balance between landmark matching accuracy and shape variability .
differences show statistical significance ( p < 0.05 in a student 's paired t - test ) with the exception of vertices close to the head ( 50% : p = 0.4073 , 80% : p = 0.0895 ) .
to further quantify the more natural shapes produced by gdas , we examine the curvature of the resulting segmentations . for each patient
examined , the integrated sum of squares of principal curvatures is shown in figure 10 . in all but one case , the gdas algorithm results in surfaces with less curvature .
the differences are statistically significant ( p < 0.0001 in a student 's paired t - test ) . to further quantify the performance and robustness of our landmark matching algorithm , we evaluate it using simulated data such that the gold standard segmentation can be precisely known . figure 11 shows example results of our landmark matching algorithms as described in section 4.5 , with traditional landmark matching shown on the left side ( green ) and gdas landmark matching shown on the right side ( blue ) . from top to bottom , the additive noise in landmark placement increases from 1/10 to 10 times that expected from voxel size in our case study ( variance 0.004475 , 0.04475 , 0.4475 , 4.475 , and 44.75 ) . at low levels of landmark uncertainty , the two algorithms give very similar results . however
, as landmark uncertainty increases , the performance of gdas exhibits a graceful decline , while that of traditional lddmm demonstrates a precipitous drop .
note that third row gives a level of landmark uncertainty comparable to that in our case study .
figure 12 shows scores as a function of landmark noise for each of the five simulated cases ( desaturated colors ) , as well as for the average performance ( saturated colors ) .
consistent with our expectations of improved robustness , we see a much smaller variability in scores for gdas . furthermore , consistent with our earlier discussion of accuracy , we see poor performance of traditional lddmm due to overfitting untrustworthy data .
note that the third data point ( close to the left - hand side of the figure ) corresponds to a level of landmark uncertainty comparable to that in our case study . for the gdas results , we can also express accuracy by measuring the error in pca coefficients recovered by the algorithm . a natural way to do this is through the mahalanobis distance ( treating the inverse of the covariance matrix as a bilinear symmetric operator defining an inner product ) .
loosely , this distance is the square root of the sum of squares of differences in pca coefficients ; each being first divided by its respective standard deviation . at the five levels of landmark noise
examined , the distance between the true coefficients and those recovered by gdas ( summed over the 31 coefficients ) is given by 0.8100 , 2.0484 , 4.0477 , 5.5894 , and 5.7708 standard deviations . however ,
the lower order coefficients , which contribute more to overal shape , are recovered with more accuracy than the higher ones .
the first coefficient is recovered with an error of 0.0154 , 0.0259 , 0.1422 , 0.4338 , and 0.6215 standard deviations , and the first 5 with an error of 0.0813 , 0.2791 , 0.5213 , 1.6052 , 2.0663 standard deviations .
we calculate the mahalanobis distance from the origin for each of the 650 patients in our adni training set and use the empirical distribution to calculate p values .
surfaces are colored by their p value and binned for p between the values { 0,0.01,0.05,0.1,0.5,1}. each column represents one bin , and five - example cases per bin are shown .
it is evident that such a distance is descriptive of the naturalness of anatomical shapes , with low p values corresponding to unnatural shapes .
using such a tool to identify outliers for targeted quality control is the subject of future research .
an extension of this idea is the ability to generate random anatomical shapes and quantify their typicality with p values .
some examples are shown in figure 13(b ) , with format paralleling what was discussed above .
this tool demonstrates the generative nature of the gdas framework and may prove to be useful for didactic or other purposes .
volumetric segmentation has played an essential role in computer - based interpretation of medical images .
there have been many approaches published to address this challenge [ 1 , 5158 ] .
most segmentation methods use a combination of shape constraint and data attachment to achieve their goals .
data attachment can be based on geometric data , gray levels , edge detection , or unstructured segmentation like k - means or gaussian mixtures . in this paper , we have demonstrated applications of the gdas framework with data attachment based on landmarks , surfaces , and likelihood ratios from grayscale values . for the case of landmark matching , we demonstrated how it could be used to remove or hasten a laborious quality control phase of large - scale neuroanatomical studies .
we quantified its improvement over an existing method based on accuracy , as well as robustness .
as is typical of bayesian analysis , we originally expected to see a tradeoff between accuracy and robustness .
however , our results showed improvements in both , likely due to overfitting to noisy data in the standard method , reducing accuracy .
the gdas algorithm shows improvement over traditional landmark matching in scores and surface - to - surface distances , as compared to the gold standard segmentation .
qualitatively , improvements are particularly noticeable in the region around the hippocampus ' head ( where landmark placement is uncertain ) .
the segmentations resulting from gdas appear natural , reflecting the typicality and variability of the population from which the pca basis was determined .
this naturalness was quantified in terms of reduced curvature as compared to the traditional method and can be understood in terms of mahalanobis distance p values .
we have found in large sample studies that robustness is accommodated by our gdas methods controlled by the pca dimensions empirically trained from samples of subcortical anatomy . in a study with over 400 hand placements of landmarks in hippocampus and amygdala , we have found that robust gdas detects our failed landmark based mappings using p - values , supporting the notion that it provides direct method for quality control of large deformation mappings .
our method is based on the geodesically controlled diffeomorphism constraints associated with the momentum conservation law .
encoding structure via prior distributions which are empirically trained has a longstanding tradition in active shape and appearance modeling [ 4 , 62 ] , defined on landmark structures as well as on higher dimensional structures as proposed in [ 3 , 63 , 64 ] .
our principal contribution here has been to encode the diffeomorphism constraint into the standard active shape models . by incorporating the conservation law controls
, we not only inherit the power of diffeomorphic transfer of the submanifold surface in the background 3d space , as has been described in [ 7 , 8 ] , but also obtain the metric structure property .
along the geodesic path connecting templates and targets ; the metric structure of the large space is maintained .
these properties have been explicitly modelled in our own methods previously using deformable templates acted upon by diffeomorphisms and embedding them into the associated metric space structures [ 12 , 65 ] .
these formulations have tended to explicitly model the transformations on the entire dense background space , working to minimize a cost function accumulated over the entire space . in the setting where the template consists of a collection of homogeneous substructures
in fact , qiu and miller have used dense deformations for statistical modeling in such settings via their support on the boundaries of the cortical substructures . | this paper presents recent advances in the use of diffeomorphic active shapes which incorporate the conservation laws of large deformation diffeomorphic metric mapping .
the equations of evolution satisfying the conservation law are geodesics under the diffeomorphism metric and therefore termed geodesically controlled diffeomorphic active shapes ( gdas ) .
our principal application in this paper is on robust diffeomorphic mapping methods based on parameterized surface representations of subcortical template structures .
our parametrization of the gdas evolution is via the initial momentum representation in the tangent space of the template surface .
the dimension of this representation is constrained using principal component analysis generated from training samples . in this work ,
we seek to use template surfaces to generate segmentations of the hippocampus with three data attachment terms : surface matching , landmark matching , and inside - outside modeling from grayscale t1 mr imaging data .
this is formulated as an energy minimization problem , where energy describes shape variability and data attachment accuracy , and we derive a variational solution .
a gradient descent strategy is employed in the numerical optimization . for the landmark matching case , we demonstrate the robustness of this algorithm as applied to the workflow of a large neuroanatomical study by comparing to an existing diffeomorphic landmark matching algorithm . |
foreign body airway ( fba ) must be suspected when a child is presented with sudden onset of respiratory distress , particularly , when presentation is unique even without a history of aspiration .
subcutaneous emphysema ( sce ) and pneumomediastinum are rare presentation of fba ; only few cases have been reported .
a 3-year - old female child was brought to the hospital with complaints of cough , difficulty in breathing , fever and swelling over the right side of chest , neck and face for last 2 days .
auscultation revealed diminished air entry with fine crepitations on the right side of the chest without any rhonchi .
her x - ray of the chest depicted sce and pneumomediastinum with infiltrates in the middle zone of the right lung without any evidence of collapse of the lung and the presence of fluid or air in the pleural cavity .
there was no evidence suggestive of foreign body ( fb ) [ figure 1 ] .
figure1 : x - ray chest showing subcutaneous emphysema , pneumomediastinum , and infiltrates in right lung middle zone she was initially diagnosed as a case of pneumonitis with barotrauma and put on antibiotic therapy .
as there was no clinical improvement and cause of sce without pneumothorax was also not clear , therefore , diagnostic bronchoscopy under general anesthesia was planned .
standard monitors were applied for monitoring heart rate , noninvasive blood pressure and pulse oximetry .
anesthesia was induced with an inhalational technique using oxygen , nitrous oxide ( 50:50 ) and halothane 1 - 2% delivered through ayre 's t piece face mask with spontaneous ventilation .
succinylcholine 20 mg was administered intravenously ( iv ) and direct laryngoscopy was attempted but it revealed no abnormality .
it was followed by tracheobronchoscopy with richard wolf rigid ventilating bronchoscope size 5 mm od .
left side bronchoscopy revealed normal study , but on the right side a granulation tissue was detected .
on careful examination and removal of granulation tissue , a fb was detected just near the origin of apical branch of right main bronchus , embedded in the mucosa .
it was a plastic piece in tortoise shape with multiple sharp pointed projections measuring 5 mm 9 mm [ figure 2 ] . during the procedure , the child was ventilated gently through bronchoscope with oxygen , nitrous oxide ( 1:1 ) and halothane 1 - 2% . besides the initial dose , only two intermittent doses of succinylcholine ( 5 mg iv each ) were required .
foreign body retrieved from right main bronchus she was given steroids ( dexamethasone-2 mg and hydrocortisone-50 mg ) intravenously .
her trachea was intubated with a tracheal tube ( 4 mm i d ) to provide chest physiotherapy and endotracheal suction was done to remove secretions .
lignocaine 1% 1 ml was instilled intratracheal through endotracheal tube to reduce the irritation of the tracheobronchial tree and hence , to control cough reflex .
, she was given humidified oxygen by face mask ( fio2 : 0.35 ) for 6 h. she maintained her spo2 above 96% in postoperative period .
sce reduced gradually within next 48 h without any subsequent intervention . on 3 day , x - ray of the chest revealed no abnormality [ figure 3 ] , and the child was discharged to the care of her parents .
definitive history of fb aspiration , a sudden appearance of respiratory symptoms and radiological investigations play an important role in making diagnosis of fb in the airway . in some cases , parents of small kids
may not be aware of the incident of aspiration ; hence even if there is no history of fb aspiration but sudden onset of respiratory symptoms , the treating physician must suspect fb airway .
recurrent episodes of wheezing , coughing , choking and sudden onset of asthma indicate a possibility of fb aspiration .
after fb aspiration , following symptomatic phase , there may be a symptom free period which may vary from days to months depending on the size , nature and site of fb .
patient of fba may present as a case of asthma , bronchiectasis , pneumonitis or hemoptysis without any underlying cause and are often misdiagnosed . besides the history and signs , various investigations are useful to confirm the diagnosis .
chest x - ray findings may not confirm the diagnosis as radio - opaque foreign bodies are rare , but associated findings such as hyperinflation , mediastinal shift and pneumonitis , secondary to fb may contribute to the diagnosis . magnetic resonance imaging and computed tomography scan have been suggested as more useful investigations for the definitive diagnosis and location of foreign bodies .
ramadan et al . reported a 2-year - old male child with fb in the airway , who presented with sce .
first is related with the fb in airway which behaves as a one - way valve allowing air to enter but not exit out of the affected part of the lung causing trapping of air , gradually increasing the distal volume and pressure .
this forms a sufficient pressure gradient across the alveoli causing rupture of the alveolar membrane through which air travels along the blood vessels to the mediastinum .
second mechanism is due to mechanical disruption of the mucosal membrane of bronchus or airway through which air enters in the tissue under pressure . during the cough or respiratory distress ,
high pressure gradient is generated to push the air through disrupted mucosal membrane which travels along perivascular and peribronchial interstitial tissue to the mediastinum resulting in pneumomediastinum .
air in the mediastinum moves to the subcutaneous tissue under pressure gradient through a peculiar arrangement of fascial planes in the neck , chest and abdomen which result in the development of sce .
coughing , valsalva maneuver , high airway pressure , positive end expiratory pressure ( peep ) etc .
the plastic fb with sharp projections pierced the mucosa and went into submucosal tissue making a false passage for the entry of the air into the tissue to develop sce .
muscle relaxation is required for bronchoscopy but intermittent positive pressure ventilation ippv is not advocated by some authors during bronchoscopy as positive airway pressure may worsen the condition by facilitating the more air entry through ruptured part of the mucosa into the tissue , although in the literature , to the best of our knowledge , no case has been published showing worsening of the condition following ippv in a patient of fba .
theoretically , it may worsen the condition in the patient where fb behaves as a one - way valve allowing the air to go in but not to come out of the lung causing hyperinflated lung .
ippv , in the presence of pneumothorax , is not advocated before putting the intercostal tube . in other patients ,
where cause of sce is just disruption of mucosa , the authors feel that the gentle ippv may be used with low - airway pressure , which may be achieved by using low but adequate tidal volume and slight leakage of gases .
, oxygenation may be achieved by apneic diffusion of oxygen through rigid ventilating bronchoscope , but co2 elimination is not possible with this method .
we conclude that the cases of fba which present with respiratory distress and sce without history of aspiration may be misdiagnosed .
bronchoscopy , a diagnostic as well as therapeutic procedure for fba , is a challenge for anesthesiologists .
ippv may be used safely during bronchoscopy without putting intercostals drain tube in the absence of pneumothorax in a patient of fba with sce . | foreign body airway ( fba ) is a common problem among the children .
variable presentation makes it difficult to diagnose a case of fba , particularly , when no definite history of aspiration is available .
subcutaneous emphysema ( sce ) and pneumomediastinum are rare presentations .
we report a case of fba who presented with sce without any history of aspiration .
a 3-year - old female child was admitted with respiratory distress , fever and sce over the right side of chest , neck and face .
initially , she was diagnosed as a case of pneumonitis with barotrauma .
x - ray of the chest revealed sce with pneumomediastinum without pneumothorax . diagnostic bronchoscopy with rigid ventilating bronchoscope
was done under general anesthesia .
a plastic foreign body with sharp projections embedded in the mucosa was detected and retrieved from right main bronchus .
postoperatively sce regressed gradually . |
pregnancy is considered high - risk when there are potential complications that could affect the mother , the baby or both .
it carries greater stress to the mother as well as her foetus than an uncomplicated pregnancy .
chronically compromised uterine perfusion can lead to placental insufficiency and subsequent intrauterine growth retardation ( iugr ) from the high - risk pregnancies .
these iugr foetuses have a decreased physiological reserve and hence are at a higher risk of peripartum complications . in addition , iugr is also associated with prematurity , low apgar scores and foetal distress .
hence , antenatal surveillance for foetal biophysical profile and intensive intrapartum monitoring for better neonatal outcome is recommended in these pregnancies .
it has been shown in various studies that by sympathectomy , epidural analgesia reduces uterine and umbilical arterial vascular resistance and therefore improves uteroplacental blood flow .
antenatal administration of epidural local anaesthetics is reported to have improved placental blood flow and resulted in increased duration of gestation and birth weight of the babies of severely preeclamptic mothers .
ropivacaine is a long acting amide local anaesthetic . in equipotent doses , it has analgesic potency similar to bupivacaine , but incidence of motor blockade , cardiovascular and central nervous system toxicity is less .
ropivacaine infusion is associated with lower rate of instrumental delivery and also with better neonatal outcomes as compared to bupivacaine .
intramuscular opioids are commonly used as an alternative to epidural local anaesthetics for labour analgesia .
we compared two different techniques of labour analgesia - epidural ropivacaine with intramuscular tramadol in high - risk parturients with iugr by measuring neonatal outcome using apgar scores ; cord blood gases , sugar , ionised calcium ; any need for resuscitation or any adverse effects .
we also compared maternal satisfaction , the duration of onset of analgesia , haemodynamic , sensory and motor block , duration of first stage of labour , modes of deliveries and maternal complications .
a total of 48 parturients admitted to the labour room who met the inclusion criteria were enrolled in this study .
term high - risk pregnant women with iugr , documented sonographic foetal weight 1500 g having singletone foetus with cephalic presentation and in active phase of labour were enrolled in our study .
patients who refused or had any contraindication to regional technique , congenital malformation of foetus , antepartum haemorrhage , coagulopathy / thrombocytopaenia ( platelets count < 75,000/l ) , intrauterine infection and any allergy to ropivacaine or tramadol were excluded from the study .
a written informed consent was taken from all participating women before the onset of labour .
information on maternal history of present pregnancy , relevant past history and routine investigations were received .
onset of labour was defined as the presence of regular painful uterine contractions , i.e. three regular painful contractions over 10 min together with at least one mucoid or blood show , cervical dilatation of 3 cm or spontaneous rupture of membrane . in the labour room , intravenous access was secured with 20/18-gauge cannula and 500 ml of lactated ringer 's solution was administered to all women 20 min before the start of analgesia . on admission to the labour room and before the first request for pain relief , all women were divided into two groups non - randomly ; group tramadol ( t ) or group epidural ( e ) for analgesia . in epidural group , all the procedures were conducted inside the operation theatre under monitoring with strict aseptic precautions . with the patient in flexed left lateral position and local skin infiltration with 2% lignocaine 23 ml ,
a multiorifice catheter was then inserted 34 cm inside the epidural space and secured at skin with a sterile dressing .
epidural ropivacaine 0.15% , 10 ml plus 30 g fentanyl bolus dose was given in incremental fashion ( 3 ml-4 ml-3 ml ) after negative aspiration for blood or cerebrospinal fluid each time .
this was followed by a continuous infusion of 0.1% ropivacaine plus 2 g / ml fentanyl at 515 ml / h with a syringe pump .
analgesia was measured using visual analogue scale ( vas ) at every 10 min interval for 1 hour , then hourly and if the vas was > 3 , a rescue bolus of 5 ml of the same drug was administered through the syringe pump .
sensory block testing was conducted caudal to t10 dermatome with wooden tooth prick ( sharp end ) at the start of analgesia and repeated hourly .
patients in tramadol group received intramuscular tramadol hydrochloride 1 mg / kg ( with maximum dose 400 mg/24 h ) every 46 h. if additional doses were required , half of the initial dose was given .
if patients complained of nausea or vomiting , antiemetic ondansetron 4 mg intravenous injection was administered .
maternal monitoring was done using continuous electrocardiography , non - invasive blood pressure ( bp ) and pulse oximetry via multichannel monitor ( csi criticare , waukesha , wisconsin , usa ) .
bp was recorded every 10 min initially for 1 h after test drug administration and thereafter at hourly interval .
maternal satisfaction was assessed within 24 h of delivery by an obstetrician ( not participating in this study ) on a four point descriptive score of excellent , good , fair or poor .
duration of the first stage , mode of delivery and the indication for caesarean section ( if done ) was also recorded .
maternal hypotension was defined as systolic bp < 90 mmhg or reduction in arterial bp > 30 mmhg from base line . for treatment of hypotension , boluses of phenylephrine
oxytocin was given as per american college of obstetrics and gynaecology ( acog recommendations 1987 ) .
the foetuses were monitored using continuous cardiotocography ( ctg ) ( huntleigh health care monitor , united kingdom ) .
ctg was recorded every half hourly after contraction . in case of any foetal heart trace abnormality
neonatal outcome was assessed by the attending paediatrician ( blinded ) with umbilical cord blood gases ( arterial blood gas / venous blood gas ) : ph , base deficit , sugar , ionic calcium , apgar score at 1 min and 5 min ( perinatal asphyxia defined as an apgar score of < 7 at 5 min and evidence of encephalopathy within the first 6 h of life ) , any requirement for resuscitation such as oxygen supplementation , face - mask application , intubation , naloxone usage , admission to neonatal intensive care was also noted .
all the women were monitored for 24 h postpartum period for complications such as hypotension , motor weakness , urinary retention , nausea or vomiting , allergy and fever .
sample size was calculated based on assumed difference of base deficit of cord blood of two groups with 80% power . for each group
normally distributed data were expressed as mean sd and the two groups were compared for their means using the student 's t - test .
skewed data were expressed as median and interquartile range and the distribution between two groups was compared using the mann
haemodynamic data were compared by repeated measure anova . repeated ordinal data ( vas , modified bromage score ) was also analysed using two - way repeated measure anova .
nominal data between the two groups were compared using chi - square test or fisher 's exact test , whichever was applicable . a p < 0.05 was considered significant .
this prospective study was conducted in collaboration with the departments of obstetrics and gynaecology in our institute ( july 2010june 2012 ) .
all pregnancies were hospital supervised and under strict antenatal surveillance with daily monitoring of biophysical profile as they were high - risk pregnancies .
co - morbidities associated with the enrolled parturients were rheumatic heart disease , hypothyroidism and anaemia with pregnancy - induced hypertension noted as the most common subclass [ table 1 ] .
co - morbidities in parturients of both groups maternal demographic characteristics the study included women of mixed parity , but majority were primigravidae . the mean gestational age of women was comparable in both the groups [ table 2 ] .
twenty - one women in group e and 19 in group t were induced with prostaglandin followed by oxytocin infusion for augmentation of labour in titrated doses according to institutional protocol . the time to onset of satisfactory analgesia
was defined as time taken from the administration of analgesia to achieve adequate pain relief , i.e. vas <3 . in group e ,
slightly faster onset of adequate analgesia was observed as compared to group t ( 17.1 2.3 min vs. 18.1 2.1 min , respectively ) , not statistically significant ( p = 0.27 ) .
parturients in group e experienced better pain control with lower vas [ figure 1 ] .
mean cord blood ph was significantly better in group e with less base deficit [ table 3 ] .
neonatal acidosis was seen in three neonates in group t with a cord ph 7.09 , 7.16 , and 7.14 and base deficit of 9.4 , 8.4 , and 8.5 mmol / l .
baseline cord blood sugar and ionic calcium were on lower side of normal level , but it was better before starting breast feeding in group e [ table 3 ] . mean birth weight of the neonates in the both groups was comparable .
mean 1-min apgar score was significantly low in group t [ table 3 ] , but was comparable at 5-min .
low 1-min apgar score , i.e. , < 5 were seen in 5 neonates ( n = 4 in group t and n = 1 in group e ) . of these , one baby in group e and one in group t received oxygen supplementation using oxygen hood ( head box ) .
the other neonate of group t with low 1-min apgar score required short - term intubation and positive pressure ventilation .
the mean duration of the 1st stage of labour in the two groups was comparable ( p = 0.19 ) .
forty - six percentage of women in group t compared to 33% in group e underwent emergency caesarean delivery due to non - reassuring foetal heart trace pattern .
the mode of delivery including vaginal and caesarean were comparable between the two groups ( p = 0.55 , p = 0.27 ) .
maternal haemodynamic during labour analgesia was more stable in group e. heart rate fluctuation was also less [ figure 2 ] .
lower but within normal range of bp reading was recorded in group e. there was no incidence of hypotension observed in any patient during the study period .
no incidence of significant motor block ( assessed by modified bromage score < 3 ) , respiratory depression ( respiration rate < 8/min ) , pruritus or fever was observed in any of the study patients .
nausea and vomiting was observed in five women for single episode in group t and one in group e although this difference was not statistically significant ( p = 0.19 ) .
higher satisfaction rates were reported with the use of epidural analgesia ( p = 0.0001 ) [ figure 3 ] .
mean visual analogue scale for pain in parturients between the two groups mean heart rate ( beats per min ) in parturients of both the groups maternal satisfaction regarding labour analgesia in both groups
in our study , we found favourable neonatal cord blood gas and other parameters in continuous epidural labour analgesia in high - risk pregnancies with iugr of mixed aetiologies .
there may be possibilities of transient hypoperfusion of placental units during uterine contraction but this does not cause any deleterious effects on foetuses .
reported a transient decrease in placental blood flow during uterine contraction in epidural labour analgesia in normal term pregnancies .
comparable analgesia between epidural tramadol and pethidine have been reported . in a cochrane data base , elbourne et al .
there was no evidence of difference between pethidine or tramadol in terms of pain relief , interval to delivery or instrumental or operative delivery .
yue concluded that although tramadol is useful alternative when patients do not opt for neuraxial anaesthesia , it may not provide satisfactory analgesia . in the present study ,
maternal satisfaction was also rated higher as most of them desired epidural analgesia in future .
this is similar to other reported studies where better pain relief and higher maternal satisfaction has been reported with epidural analgesia .
studies show that antepartum epidural local anaesthetics induce uterine vasodilatation directly as well as redistribute blood away from competing vessel in favour of uteroplacental blood flow . unlike systemic vasodilators
probably , from the value of neonatal data , it appears that the effect of tramadol analgesia is not favourable for improving placental circulation .
there are a few reports in literature where authors reported foetal acidosis with the use of regional anaesthesia for caesarean delivery . in a population
based cohort study of very preterm babies ( 2732 weeks ) , investigators found a significantly higher risk of mortality in neonates of mothers who received spinal anaesthesia ( sa ) for caesarean delivery as compared to general anaesthesia probably due to inadequate maternal haemodynamic control and undetected placental hypoperfusion .
foetal acidosis with sa in severely pre - eclamptic parturients undergoing emergency caesarean delivery has been reported ; a significantly greater mean arterial base deficit indicating anaerobic metabolism due to metabolic acidosis in the foetus was observed in the study .
since data are limited in this sub - group of maternal population receiving labour analgesia , we need further studies with larger sample size to know the neonatal effects of labour analgesia in pregnancies with iugr .
unlike the above mentioned studies , we tried to maintain good haemodynamic during labour analgesia . in our study ,
studies have shown that significant elevation in blood flow resistance indicates loss of effective foetal maternal exchange area in the placenta .
raised doppler indices may reflect serious deterioration in foetal growth associated low apgar and cord gas values . though baseline neonatal cord blood sugar and ionic calcium level in both groups were on lower side , they were significantly better before starting breast feeding in epidural group
. probably , this resulted due to reduction of stress and catecholamine by epidural local anaesthetics . in our study ,
none of the women developed significant hypotension , motor blockade , urinary retention or pruritus .
similar stable maternal haemodynamic following continuous infusion of epidural local anaesthetics was reported in chen 's study .
well - controlled and effective epidural blockade may provide improved neonatal cord blood gas parameters probably resulting from better uteroplacental perfusion along with adequate intrapartum pain relief in parturients with iugr .
| background and aims : low concentration local anaesthetic improves uteroplacental blood flow in antenatal period and during labour in preeclampsia .
we compared neonatal outcome after epidural ropivacaine plus fentanyl with intramuscular tramadol analgesia during labour in high - risk parturients with intrauterine growth restriction of mixed aetiology.methods:forty-eight parturients with sonographic evidence of foetal weight < 1.5 kg were enrolled in this non - randomized , double - blinded prospective study .
the epidural ( e ) group received 0.15% ropivacaine 10 ml with 30 g fentanyl incremental bolus followed by 715 ml 0.1% ropivacaine with 2 g / ml fentanyl in continuous infusion titrated until visual analogue scale was three .
tramadol ( t ) group received intramuscular tramadol 1 mg / kg as bolus as well as maintenance 46 hourly .
neonatal outcomes were measured with cord blood base deficit , ph , ionised calcium , sugar and apgar score after delivery .
maternal satisfaction was also assessed by four point subjective score.results:baseline maternal demographics and neonatal birth weight were comparable .
neonatal cord blood ph , base deficit , sugar , and ionised calcium levels were significantly improved in the epidural group in comparison to the tramadol group . maternal satisfaction ( p = 0.0001 ) regarding labour analgesia in epidural group was expressed as excellent by 48% , good by 52% whereas it was fair in 75% and poor in 25% in the tramadol group .
better haemodynamic and pain scores were reported in the epidural group.conclusion:epidural labour analgesia with low concentration local anaesthetic is associated with less neonatal cord blood acidaemia , better sugar and ionised calcium levels .
the analgesic efficacy and maternal satisfaction are also better with epidural labour analgesia . |
townes - brocks syndrome ( tbs ) is a genetic condition that affects several parts of the body , including most commonly imperforate anus , abnormally shaped ears , and hand malformations that mostly affect the thumb .
other possible signs and symptoms of tbs consist of hearing loss , foot malformation , heart defects , genitourinary abnormalities , and rarely eye abnormalities1 ) . intellectual disability , learning problems , and mental retardation have also been reported in about 10 percent of people with tbs2 - 3 ) .
tbs is confirmatively diagnosed with a mutation in the sall1 gene , a part of sall genes that provide instructions for making proteins in the formation of tissues and organs before birth4 ) .
the syndrome is inherited by an autosomal dominant pattern or by a sporadic mutation without familial inheritance .
we , herein , report a family whose members were diagnosed of tbs with congenital hypothyroidism and had a novel sall1 gene mutation .
a 4-month - old male infant was born vaginally at 37th week of gestation with a birth weight of 2,600 g after an uneventful pregnancy . at birth , he was noted to have unusually shaped ears with preauricular tags on the right ear ( fig .
analysis on 24-hour urine specimen showed urine output of 1.12 ml / kg / hr ; protein 1.75 mg / m / hr ; and the calculated creatinine clearance 14.47 ml / min/1.73 m/24hr .
ophthalmologic examination revealed aniridia of the right eye , but orbit computed tomography ( ct ) was unremarkable .
neonatal thyroid screening test revealed abnormal results ( tsh 99.70 u / ml ; t3 102 ng / ml ; free t4 1.11 ng / dl ) , which resulted in thyroxine replacement therapy for congenital hypothyroidism .
family history taking revealed an older brother with imperforate anus , congenital heart defect , malformation of the ears with right sided preauriclar tag , polydactyly of right thumb , and congenital hypothyroidism , who had expired at the age of 3 months from complications of cardiac surgery .
the patient also had a 4-year - old sister with bilateral low set ears but no other abnormal features .
his mother had a history of a mild anal atresia at birth , bilateral dysplastic ears , hypoparathyroidism , bilateral sensorineural hearing loss which was corrected with hearing aids , and a ventricular septal defect which had spontaneously closed .
his maternal grandmother 's younger brother had malformation of both ears , but no hearing defect .
clinical findings of the patient and pertinent family history suggested the possibility of tbs ( fig .
mutation analysis of exons 1 , 2 , and 3 of sall1 gene in the 16q12.1 was performed on the patient and his mother , which showed a heterozygous single base pair deletion at nucleotide position 1470 ( c.1470delg ) in exon 2 ( fig .
this deletion is predicted to cause a frameshift mutation , leading to a truncated sall1 protein .
townes - brocks syndrome ( tbs ) is a rare autosomal dominant multiple malformation syndrome with clinical variability within and between affected families .
characteristic features suggested for tbs include the following : anorectal abnormalities ( imperforate anus ) , abnormalities of the hands ( preaxial polydactyly , triphalangeal thumbs ) , abnormalities of the feet ( syndactyly , club foot ) , deformities of the outer ear ( " lop ears " ) and preauricular tags , and sensorineural hearing loss5 ) .
other reported anomalies include congenital heart defects ( vsd , tof)6 , 7 ) , genitourinary abnormalities ( impaired renal function or renal failure , hypoplastic or multicystic kidney , posterior urethral valve , vesicoureteral reflux ) , hypothyroidism , meatal stenosis8 , 9 ) , and rarely eye abnormalities ( colobomata , aniridia ) may be associated . due to the involvement of multiple organ systems , early recognition of the disorder ,
appropriate medical management , and genetic counselling of the syndrome is critical . to the best of our knowledge ,
five cases of tbs have thus been reported to be associated with hypothyroidism5 , 10 - 13 ) .
although thyroid function test is included in the routine neonatal screening test , the result of the test should be reconfirmed in tbs patients . as features of tbs
frequently overlap those seen in other genetic syndromes , tbs may considerably have been misdiagnosed as other genetic disorders .
tbs patients may have hand malformation or radial bone abnormalities , but no structural vertebral abnormalities or tracheo - esophageal fistula .
vacterl association may have vertebral abnormalities and tracheo - esophageal fistula , but no ear anomalies or deafness14 - 16 ) . baller - gerold syndrome usually presents with craniosynostosis and thumb anomalies but no hypoplastic thumb17 ) .
cat eye syndrome has tracheo - esophageal fistula and vertebral anomalies but no thumb anomalies14 ) .
tbs is caused by a dominantly inherited defect in the gene encoding the sall1 putative transcription factor , a protein possibly required for urological , renal , limb , ear , brain , and liver development17 ) .
sall1 gene is located on 16q12.1 and comprises three exons encoding a zinc finger protein thought to act as a transcriptional repressor .
mutations in sall1 result in prematurely terminated sall1 protein with loss of all double zinc - finger domains presumably essential for gene function .
more than 56 mutations in the sall1 gene have been identified in patients with townes - brocks syndrome .
sall1 mutations have been found in 64.3 - 83.3% of patients with typical signs of tbs , the majority of which are frame - shift mutations5 ) .
the patient with townes - brocks syndrome associated with congenital hypothyroidism in this report was confirmed to have a novel single base pair deletion at nucleotide position 1470 ( c.1470delg ) in exon 2 of sall1 gene , resulting in a frameshift mutation which was inherited from his mother . | townes - brocks syndrome ( tbs ) is a rare autosomal dominant congenital disorder caused by mutations in the sall1 gene .
its signs and symptoms overlap with other genetic syndromes , including vacterl association , pendred syndrome , baller - gerold syndrome , and cat eye syndrome .
structural vertebral abnormalities , hypoplasia of the thumb , and radial bone abnormalities , which are not usually associated with tbs , help in the differential diagnosis of these syndromes .
we report the case of a family whose members were diagnosed with tbs with congenital hypothyroidism and had a novel sall1 gene mutation . |
materials[sar , ile , ile]-angiotensin
ii was synthesized in the cleveland clinic core synthesis facility .
human recombinant epidermal growth factor ( egf ) was
purchased from roche molecular biochemicals .
the egfr - specific inhibitor
tyrphostin ag1478 , the src - specific inhibitor
4-amino-5-(4-chlorophenyl)-7-(t - butyl)pyrazolo[3,4-d]pyrimidine
( pp2 ) , the mek inhibitor pd98059 , and n - phenylsulfonyl hydroxamic
acid derivative
( 2r-[(4-biphenylsulfonyl)amino]-n - hydroxy-3-phenylpropinamide )
( bips ) , and pkc inhibitors ( gfx , g6976 , and g6983 ) were from
calbiochem .
polyclonal anti - egfr and anti - phospho - egfr ( tyr )
antibodies used for immunoprecipitation and immunoblotting were from cell
signaling and upstate biotechnology , inc .
polyclonal rabbit -arrestin
1(a1ct ) and polyclonal rabbit anti--arrestin 2 ( a2ct ) antibodies were
used for detecting -arrestin1 and -2 , respectively
( 9 ) .
polyclonal anti - phospho - erk antibody ( cell
signaling ) and polyclonal anti - erk2 antibody ( millipore ) were used for erk
activation assay .
synthesis of small interfering rnas ( sirnas)chemically
synthesized , double - stranded sirnas , with 19-nucleotide duplex rna and
2-nucleotide 3-dtdt overhangs were purchased from dharmacon in
deprotected and desalted forms .
the sirna sequence targeting -arrestin1
is 5-agccuucugugcugagaac-3 , corresponding to position
431459 relative to the start codon .
the sirna sequences targeting
-arrestin2 are 5-ggaccgcaaaguguuugug-3 and
5-ccaacctcattgaattcga-3 , corresponding to positions
150168 and 11151133 relative to the start codon
( 10 ) .
sigenome on - target plus
set of four rat prkcz was purchased from dharmacon .
a non - silencing rna duplex
( 5-aauucuccgaacgugucacgu-3 ) , as the manufacturer indicated , was
used as a control .
cell culture and rna transfection vsmcs were prepared from
aorta of male sprague - dawley rats by enzymatic digestion
( 11 ) and maintained in medium
199 ( m199 ) supplemented with 10% fetal bovine serum and 1%
penicillin - streptomycin .
eighty to 90% confluent , slow growing early passage
( < 5 ) cells in 100-mm dishes were transfected with 20 g of sirna using
60 l of lipofectamine 2000 transfection reagent
( 11 ) .
forty - eight hours after
transfection , cells were starved with media with 0.1% bovine serum albumin for
at least 48 h prior to stimulation .
calcium fluorimetry cells were loaded with the dye fura-2 as
per the manufacturer 's instructions ( invitrogen ) , and treated with either ang
( 100 nm ) or sii ( 10 m ) , in the presence of either 1
m valsartan ( angiotensin receptor type 1 blocker , at1rb ) or 300
nm pd123319 ( angiotensin receptor type 2 blocker , at2rb ) . the
instantaneous 340/380-nm excitation ratio for fura-2 was calculated and
plotted as a function of time .
dna synthesis was determined as incorporation
of [ h]thymidine into trichloroacetic acid - insoluble material as
described ( 11 ) .
cells were
seeded 10,000 cells / well in 12-well plates and grown to subconfluence ( 1 day ) .
cells were rendered quiescent by 48 h in serum - free m199 supplemented with
0.1% bovine serum albumin and stimulated by addition of fresh medium
containing the agonists and/or inhibitors .
[ h]thymidine ( 0.5
ci / ml ) was added to the medium at the time of stimulation .
cells were
washed twice with phosphate - buffered saline and three times with 0.5%
trichloroacetic acid , and then cells were lysed with 1 n naoh .
extent of cell growth was determined by counting incorporation of
[ h]thymidine into nascent dna strands .
immunoprecipitation
was performed by a modification of the methods of daub et al .
cells were serum - starved
in m199 with 0.1% bovine serum albumin for 48 h after sirna transfection .
stimulation of serum - starved rat vsmc in 100-mm dishes with appropriate
agonists was done at 37 c for 2 min .
after stimulation , monolayers were
washed once with ice - cold phosphate - buffered saline and lysed in buffer
containing 50 mm hepes ( ph 7.5 ) , 150 mm nacl , 1% triton
x-100 , 1 mm edta , 10% glycerol , 10 mm sodium
pyrophosphate , 2 mm sodium orthovanadate , 10 mm sodium
fluoride , 1 mm phenylmethylsulfonyl fluoride , and 10 g / ml
aprotinin . the egfr was immunoprecipitated using 4 g of anti - egfr antibody
plus 25 l of 50% slurry of protein g plus / protein a - agarose and agitated
overnight at 4 c .
western blotting was performed to detect
phosphorylation residues at tyr-845 of the egfr with antibody ( cell
signaling ) . for western
blotting for erk activation , vsmcs on 6-well plates were
starved for at least 48 h in serum - free medium prior to stimulation .
after
stimulation , cells were solubilized by directly adding the 2 sds sample
buffer followed by sonication .
aliquoted cells after transfection were
solubilized in a lysis buffer , as described previously
( 13 ) , to measure the protein
concentration .
equal amounts of cellular extracts were separated on
420% tris glycine polyacrylamide gels and transferred to nitrocellulose
membranes for immunoblotting .
phosphorylated erk1/2 , total erk1/2 , and
-arrestins were detected by immunoblotting with rabbit polyclonal
anti - phospho - erk ( cell signaling , 1:2,000 ) , anti - erk ( upstate technology inc ,
1:10,000 ) , and anti--arrestin ( a1ct , 1:3,000 and a2ct , 1:3000 )
antibodies , respectively ( 9 ) .
chemiluminescent detection was performed using the supersignal west pico
reagent ( pierce ) , and all the immunoblots were visualized and quantified by
bio imaging system ( syngene ) .
the levels of erk phosphorylation was normalized
to a loading control ( total erk ) .
statistical analysis was done using a
one - way analysis of variance ( anova ) ( prism software ) to correct for multiple
comparisons ( bonferroni 's multiple comparison test ) with post test .
figure 1.mobilization of calcium , dna synthesis , and phosphorylation of erk
stimulated by ang and sii in vsmcs .
a , vsmcs were loaded with the
calcium - binding dye fura-2 , and stimulated either with ang ( 100 nm )
or sii ( 10 m ) in the presence or absence of pretreatment with
the at1r antagonist ( at1rb ) valsartan ( 50 m ) or at2r
antagonist ( at2rb ) pd123319 ( 30 m ) .
calcium
fluorimetric traces are shown with the 340/380 nm excitation ratio ( y
axis ) plotted as a function of time ( x axis ) .
b , vsmcs were
serum starved for 24 h to arrest cycling and pretreated with dimethyl
sulfoxide ( dmso ) or mek inhibitor pd98056 ( 20 m ) .
ang
( 100 nm ) , sii ( 10 m ) , or egf ( 10 ng / ml ) along with
h - labeled thymidine were then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean
s.e . of count per minute ( cpm )
statistical analysis was done using a one - way anova ( prism
software ) to correct for multiple comparisons ( bonferroni 's multiple
comparison test ) with post test .
the pd98056-pretreated condition shows
significant reduction compare with the dimethyl sulfoxide - pretreated condition
for each stimulant ( * , p < 0.05 ) .
c , vsmcs with
endogenous at1r were treated with 100 nm ang or 10 m
sii for the indicated times .
equal amounts of cell lysate were separated by
sds - page and analyzed for phosphorylated erk ( p - erk ) and total erk
( erk ) by western blotting .
d ,
signals were quantified by densitometry and p - erk was normalized to a loading
control ( erk ) .
p - erk activation was expressed as percentage of the maximal
phosphorylated erk obtained by ang stimulation at 5 min .
mobilization of calcium , dna synthesis , and phosphorylation of erk
stimulated by ang and sii in vsmcs .
a , vsmcs were loaded with the
calcium - binding dye fura-2 , and stimulated either with ang ( 100 nm )
or sii ( 10 m ) in the presence or absence of pretreatment with
the at1r antagonist ( at1rb ) valsartan ( 50 m ) or at2r
antagonist ( at2rb ) pd123319 ( 30 m ) .
calcium
fluorimetric traces are shown with the 340/380 nm excitation ratio ( y
axis ) plotted as a function of time ( x axis ) .
b , vsmcs were
serum starved for 24 h to arrest cycling and pretreated with dimethyl
sulfoxide ( dmso ) or mek inhibitor pd98056 ( 20 m ) .
ang
( 100 nm ) , sii ( 10 m ) , or egf ( 10 ng / ml ) along with
h - labeled thymidine were then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean
s.e . of count per minute ( cpm )
statistical analysis was done using a one - way anova ( prism
software ) to correct for multiple comparisons ( bonferroni 's multiple
comparison test ) with post test .
the pd98056-pretreated condition shows
significant reduction compare with the dimethyl sulfoxide - pretreated condition
for each stimulant ( * , p < 0.05 ) .
c , vsmcs with
endogenous at1r were treated with 100 nm ang or 10 m
sii for the indicated times .
equal amounts of cell lysate were separated by
sds - page and analyzed for phosphorylated erk ( p - erk ) and total erk
( erk ) by western blotting .
d ,
signals were quantified by densitometry and p - erk was normalized to a loading
control ( erk ) .
p - erk activation was expressed as percentage of the maximal
phosphorylated erk obtained by ang stimulation at 5 min .
intracellular calcium mobilization and its effect on dna synthesis and
erk activation stimulated with ang or sii ang regulates vascular
tone and induces mitogenic responses . to understand the functions of
-arrestins in endogenously expressed at1r - mediated mitogenic pathways
,
we utilized a triply mutated angiotensin octapeptide ( sii ) that acts as a
specific agonist for -arrestin - mediated signaling while not activating g
protein - mediated signaling ( 8) .
to validate the utility of sii as an activator of only
-arrestin - dependent signaling pathways in primary cultured rat vsmcs ( as
is the case with receptor - transfected hek 293 cells
( 8) ) ,
calcium influx in
response to ang and sii was measured . as shown in
fig .
1a , vsmcs treated
with ang display robust calcium mobilization , whereas cells treated with sii
shows no calcium mobilization , implying that sii can not activate g - protein
pathways in these cells .
the ang response is completely blocked in the
presence of an angiotensin receptor type 1 blocker ( at1rb , valsartan ) but not
by an angiotensin receptor type 2 blocker ( at2rb , pd 123319 )
( fig .
it is well known that erk activation plays an important role in cell
proliferation . to investigate the contribution of -arrestin - mediated erk
activation to vsmc proliferation , we studied ang- and sii - mediated dna
synthesis in vsmcs as an indicator of cell proliferation .
vsmcs were
pretreated or not with a pharmacological inhibitor ( pd98059 ) of
mitogen - activated protein kinase kinase ( mek ) followed by stimulation with 100
nm ang , 10 m sii , or 10 ng / ml egf .
although sii
can not activate classical g - protein - dependent ca fluxes
( fig .
1a ) , it
significantly increased dna synthesis ( thymidine incorporation ) to a level
similar to that provoked by ang or egf stimulation in vsmcs
( fig .
pretreatment with pd98059 ablated virtually all activation over basal levels
( n = 5 ; p < 0.05 ) , indicating that erk activation
regulates dna synthesis in vsmcs ( fig
these data indicate that a g - protein - independent erk
activation mechanism that can be stimulated by sii can mediate at1r - regulated
dna synthesis in rat vsmcs . in transfected hek 293 cells it has been demonstrated that sii elicits at1r
signaling to erk activation without activating the gq protein
( 8) .
1 demonstrates the
inability of sii to activate calcium fluxes , a classic gq response
in vsmcs , whereas retaining the ability to induce dna synthesis , which
requires erk activation .
next , we tested sii - mediated erk activation mediated
by the at1r - expressed endogenously in vsmcs .
c and
d , show that erk activation by sii in vsmcs reaches
maximal levels by 5 min , and amounted to a 2-fold increase over basal , which
was about 50% of ang - mediated erk activation .
both ang- and sii - stimulated erk
activation is completely sensitive to at1rb pretreatment in vsmcs ( data not
shown ) .
these results demonstrate that a g protein - independent pathway
contributes to erk activation in primary vsmcs through endogenously expressed
at1r .
vsmcs were transfected with the control ( ctl ) ,
-arrestin1 and -2 sirnas using lipofectamine 2000 .
a ,
representative western blot for expression of -arrestins after sirna
transfection was shown . -arrestin1 and
-2 were detected by
immunoblotting ( ib ) with rabbit polyclonal anti--arrestin1
( a1ct ) and anti--arrestin2 ( a2ct ) antibodies ,
respectively .
b d , serum - starved cells were treated with 100 nm
ang for the indicated times and cell lysates were analyzed for phosphorylated
erk ( p - erk ) and total erk ( erk ) .
b , representative
western blot for ang induced p - erk and erk in sirna - transfected vsmcs was
shown .
c and d , signals were quantified by densitometry and
p - erk was normalized to a loading control ( erk ) .
the signal at each point is
expressed as percentage of the maximal p - erk signal ( 5 min ) in ctl
sirna - transfected cells .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's
multiple comparison test ) with post test .
the sirna transfected condition
shows significant differences compared with control sirna - transfected cells at
each time point ( * , p < 0.05 ; * * , p < 0.01 ) .
vsmcs were transfected with the control ( ctl ) ,
-arrestin1 and -2 sirnas using lipofectamine 2000 .
a ,
representative western blot for expression of -arrestins after sirna
transfection was shown . -arrestin1 and
-2 were detected by
immunoblotting ( ib ) with rabbit polyclonal anti--arrestin1
( a1ct ) and anti--arrestin2 ( a2ct ) antibodies ,
respectively .
b d , serum - starved cells were treated with 100 nm
ang for the indicated times and cell lysates were analyzed for phosphorylated
erk ( p - erk ) and total erk ( erk ) .
b , representative
western blot for ang induced p - erk and erk in sirna - transfected vsmcs was
shown .
c and d , signals were quantified by densitometry and
p - erk was normalized to a loading control ( erk ) .
the signal at each point is
expressed as percentage of the maximal p - erk signal ( 5 min ) in ctl
sirna - transfected cells .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's
multiple comparison test ) with post test .
the sirna transfected condition
shows significant differences compared with control sirna - transfected cells at
each time point ( * , p < 0.05 ; * * , p < 0.01 )
. effect of -arrestin depletion on ang- and sii - mediated
erk activation as shown in figs .
1 ,
g protein - independent signaling is involved in at1r - mediated
dna synthesis via erk activation in vsmcs . in hek 293 cells , we have
previously demonstrated that -arrestins play critical roles in g
protein - independent erk activation
( 13 ) .
therefore , we examined
the effects of rna interference ( rnai)-mediated suppression of
-arrestin1 and -2 expression on the kinetics of erk activation following
stimulation with ang and sii in vsmcs .
transfection with sirnas targeting
-arrestin1 or -2 effectively and specifically silence the expression of
each -arrestin ( fig .
ang
stimulation evokes a kinetic pattern of erk activation similar to control but
with significantly elevated levels of activation at the 2-min time point ,
compared with control sirna - transfected cells
( fig .
in contrast , depletion of -arrestin2 leads to
decreased erk activation ( by over 30% ) at the later time points ( 5 to 20 min )
( fig .
sii - stimulated erk activation is completely lost in -arrestin2
sirna - transfected vsmcs ( fig .
3 , a
and b ) , suggesting that sii - stimulated erk activation is
entirely -arrestin2-mediated . to further validate the contribution of
-arrestin2 to vsmc proliferation , we measured ang- and sii - induced
thymidine incorporation as an indicator of dna synthesis and cell
proliferation in vsmcs after depletion of -arrestin1 or -2 .
ang- and
sii - induced dna synthesis was significantly inhibited only by deletion of
-arrestin2 ( fig .
these results indicate that
-arrestin2 has a major role in at1r - mediated erk signaling and cell
proliferation in vsmcs .
role of pkc in at1r - mediated erk activation in vsmcs upon
agonist binding , at1r activates gq protein , which activates
phospholipase c. active phospholipase c generates inositol triphosphate and
diacyglycerol , which increase intracellular calcium influx and pkc ,
respectively ( 14 ) .
we have
previously found that in hek 293 cells at1r - mediated g protein - dependent erk
activation requires pkc activity .
this process is rapid ( peak < 2 min ) and
quite transient ( 2 min )
( 13 ) .
therefore , we assessed
the role of pkc in mediating ang - stimulated erk activation in vsmcs by using
pkc inhibitors
. we tested several pkc inhibitors including gfx
( bisindolylmaleimide i ) , ro-31 - 8425 , g6976 , and g6983 , which
inhibit the activities of various combinations of conventional ( ,
, or ) , novel ( , , or ) , and atypical ( ,
) isoforms of pkc in a concentration - dependent way .
there was no
significant inhibition of erk activation by either 1 m
g6976 , a selective inhibitor of pkc , , and
( fig .
4a ) , or by 1
m ro-31 - 8425 ( data not shown ) , a selective inhibitor of pkc
, , , and . ang - mediated erk activation was also not
inhibited by either 1 m g6983
( fig .
4b ) or 5
m gfx ( data not shown ) , which at the concentrations tested only
inhibit the activities of pkc isoforms , , , and/or .
in contrast , pretreatment with pkc inhibitors ( 15 m gfx and 10
m g6983 ) resulted in dramatic decreases ( 75% ) in erk
activation at early time points ( 1 and 2 min ) after ang stimulation , but
little inhibition was observed at longer time points ( 10 and 20 min )
( fig .
the general pkc
activator , phorbol 12-myristate 13-acetate induced erk activation and this was
abolished by all of the pkc inhibitors used in vsmcs ( data not shown ) .
the
kinetic pattern of erk activation in the presence of the pkc inhibitors gfx
and g6983 in vsmcs ( fig .
4 ) is similar to that observed previously for ang - stimulated ,
-arrestin2-dependent erk activation in hek 293 cells expressing at1r
( 13 ) .
only early activity
( i.e. prior to 510 min of stimulation ) was inhibited .
thus ,
the temporal patterns of g protein - dependent ( pkc dependent ) and
-arrestin2-dependent erk activation through endogenous at1rs in vsmcs
are distinct from each other .
the majority of early activity ( 2 min ) is
elicited via the g protein - dependent pathway ( pkc inhibitor sensitive ) ,
whereas late activity ( > 5 min ) is predominantly mediated by the
-arrestin2-dependent pathway .
pkc mediates g - protein - dependent erk activation upon
stimulation with ang three isoforms of pkc , , , and
, have been shown to be expressed in vsmcs
( 15 ) . among them , pkc
has been implicated in ang - mediated mitogenic responses and cell growth in
vsmcs ( 16 ) , although different
isoforms of pkc may play roles in erk activation in different cell types
( 17 ,
18 ) . in
fig .
4 , we observed inhibition
of erk activation at the early time points when two pkc inhibitors capable of
blocking pkc activity were used .
furthermore , blockade of pkc and
appears not to inhibit this erk activation .
thus , we next examined the
role of pkc in erk activation in vsmcs utilizing the rnai technique .
transfection with pkc-specific sirna reduces the expression of pkc
by 70% in vsmcs ( fig . 5 , a and
b ) .
ang - induced erk activation at early time points
( < 5 min ) was significantly decreased in cells transfected with pkc
sirna compared with that in control sirna - transfected vsmcs
( fig .
5 , c and
d ) . to further validate the role of pkc in
-arrestin - dependent ( or g protein - dependent ) pathways
as shown in
fig . 5 , e and
f , sii leads to activation of erk at the same magnitude
in both control and pkc sirna - transfected cells . taken together
, these
data suggest that pkc , at least partially , mediates ang - induced early
erk activation , whereas not affecting -arrestin - dependent erk activation
in vsmcs .
a and b , vsmcs were transfected with control
( ctl ) or -arrestin2 sirnas using lipofectamine 2000 .
serum - starved cells were treated with 10 m sii for the
indicated times and cell lysates were analyzed for phosphorylated erk
( p - erk ) and total erk ( erk ) .
a , representative
western blot for sii - induced p - erk and total erk in sirna - transfected vsmcs
was shown .
b , signals were quantified by densitometry and p - erk was
normalized to a loading control ( erk ) .
signal at each point is
expressed as percentage of ang stimulated the maximal p - erk signal at 5 min in
control ( ctl ) sirna - transfected cells as depicted in
fig .
the
graph represents mean s.e . from six independent experiments .
statistical analysis in each time point of kinetic graphs were determined by
using a two - way anova ( bonferroni 's post test ) between -arrestin2 and
control ( ctl ) sirna - transfected cells ( * , p < 0.05 ) .
c , vsmcs were transfected with control , -arrestin1 or -2 sirnas
using lipofectamine 2000 and then serum starved for 24 h to arrest cycling .
ang ( 100 nm ) or sii ( 10 m ) along with
h - labeled thymidine was then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean
s.e . of fold - increase of basal counts per minute ( cpm ) values from
three independent experiments .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's post
test ) .
ang and sii significantly increase thymidine incorporation compared
with ns control ( * , p < 0.05 ) .
depletion of -arrestin2 shows
significant reduction on both ang- and sii - mediated thymidine incorporation
compared with its own agonist stimulation in the ctl sirna - transfected
condition ( * * , p < 0.05 ) .
a and b , vsmcs were transfected with control
( ctl ) or -arrestin2 sirnas using lipofectamine 2000 .
serum - starved cells were treated with 10 m sii for the
indicated times and cell lysates were analyzed for phosphorylated erk
( p - erk ) and total erk ( erk ) .
a , representative
western blot for sii - induced p - erk and total erk in sirna - transfected vsmcs
was shown .
b , signals were quantified by densitometry and p - erk was
normalized to a loading control ( erk ) .
signal at each point is
expressed as percentage of ang stimulated the maximal p - erk signal at 5 min in
control ( ctl ) sirna - transfected cells as depicted in
fig .
the
graph represents mean s.e . from six independent experiments .
statistical analysis in each time point of kinetic graphs were determined by
using a two - way anova ( bonferroni 's post test ) between -arrestin2 and
control ( ctl ) sirna - transfected cells ( * , p < 0.05 ) .
c , vsmcs were transfected with control , -arrestin1 or -2 sirnas
using lipofectamine 2000 and then serum starved for 24 h to arrest cycling .
ang ( 100 nm ) or sii ( 10 m ) along with
h - labeled thymidine was then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean
s.e . of fold - increase of basal counts per minute ( cpm ) values from
three independent experiments .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's post
test ) .
ang and sii significantly increase thymidine incorporation compared
with ns control ( * , p < 0.05 ) .
depletion of -arrestin2 shows
significant reduction on both ang- and sii - mediated thymidine incorporation
compared with its own agonist stimulation in the ctl sirna - transfected
condition ( * * , p < 0.05 ) .
serum - starved vsmcs were pretreated with vehicle ( dimethyl sulfoxide ,
dmso ) or the indicated pkc inhibitors for 30 min , and then stimulated
with 100 nm ang for the indicated times .
western blots for
phosphorylated erk ( p - erk ) and total erk ( erk ) were
performed .
a , representative p - erk western blots and targeted pkc
subtypes for pkc inhibitors were presented .
b and c , signals
were quantified by densitometry and p - erk was normalized to a loading control
( erk ) .
the percentage of p - erk was calculated for each time point and plotted
as percentage of the maximal p - erk signal with dimethyl sulfoxide at 5 min .
statistical analysis was done using a one - way anova ( prism software ) to
correct for multiple comparisons ( bonferroni 's post test ) .
pretreated
conditions with pkc inhibitors show the significant differences compared with
dimethyl sulfoxide - treated cells at the indicated time point ( * , p
< 0.05 ) .
serum - starved vsmcs were pretreated with vehicle ( dimethyl sulfoxide ,
dmso ) or the indicated pkc inhibitors for 30 min , and then stimulated
with 100 nm ang for the indicated times .
western blots for
phosphorylated erk ( p - erk ) and total erk ( erk ) were
performed .
a , representative p - erk western blots and targeted pkc
subtypes for pkc inhibitors were presented .
b and c , signals
were quantified by densitometry and p - erk was normalized to a loading control
( erk ) .
the percentage of p - erk was calculated for each time point and plotted
as percentage of the maximal p - erk signal with dimethyl sulfoxide at 5 min .
statistical analysis was done using a one - way anova ( prism software ) to
correct for multiple comparisons ( bonferroni 's post test ) .
pretreated
conditions with pkc inhibitors show the significant differences compared with
dimethyl sulfoxide - treated cells at the indicated time point ( * , p
< 0.05 ) .
ib , immunoblot . ang- and sii - mediated erk activation is dependent on egfr kinase and
metalloprotease 2/9 in vsmcs it is known that at1r - mediated egfr
transactivation plays an important role in proliferation of various cell types
including vsmcs ( 19 ) .
ang
promotes activation of the egfr pathway through release of the egfr ligand
heparin - binding egf in various cell types
( 12 ,
19 ) .
however , it is not clear
whether egfr transactivation is required for -arrestin - dependent erk
activation in vsmcs . to answer this question , we examined erk activation after
ang and sii stimulation in the presence of various pharmacological inhibitors
of components thought to be involved in the egfr transactivation pathway .
first we tested the requirement for egfr kinase activity in ang - induced erk
activation . in the presence of ag1478 , an egfr - specific kinase inhibitor ,
ang - induced erk activation is dramatically inhibited at all tested time points
( fig .
next , we investigated the contribution of egfr kinase
activity particularly for the -arrestin2-dependent pathway by testing
ang - mediated erk activation in the presence of ag1478 after depletion of
-arrestin2 .
in vsmcs transfected with -arrestin2 sirna , erk
activation was further reduced by ag1478 as shown in
fig .
6 , c and
d. ang - stimulated erk activation was inhibited by ag1478
in both control and -arrestin2 sirna - transfected vsmcs ( reduced to
4050% of maximal ang stimulation
( fig .
these data indicate that , without -arrestin2 ,
the remaining g protein - dependent component was also affected by the egfr
kinase inhibitor . thus , both g protein- and -arrestin2-dependent
components required egfr transactivation for at1r - mediated erk activation .
vsmcs were transfected with control ( ctl ) sirna or sigenome on - target
plus a set of four rat pkc sirnas ( dharmacon ) using lipofectamine 2000 .
a , representative western blot for expression of pkc and actin
after sirna transfection was shown .
b , the expression levels of
pkc after sirna transfection were measured by western blot and
normalized with its loading control ( actin ) .
data represent mean s.e .
from four independent experiments ( * , p < 0.05 ) .
c f , sirna - transfected and serumstarved vsmcs were stimulated
by 100 nm ang or 10 m sii for the indicated times
and cell lysates were analyzed for phosphorylated erk ( p - erk ) and
total erk ( erk ) .
c and e , representative p - erk and
erk western blots were presented for ang ( c ) and sii ( e )
stimulation .
d and f , signals were quantified by
densitometry and p - erk was normalized to a loading control ( erk ) .
signal at each
point is expressed as percentage of the maximal p - erk signal - stimulated ang
for 5 min in ctl sirna vsmcs .
d , statistical analysis was done using
a one - way anova ( prism software ) to correct for multiple comparisons
( bonferroni 's post test ) for ang - induced erk activation in pkc
sirna - transfected cells compared with ctl sirna - transfected cells at each time
point ( * p < 0.05 ) .
f , sii - induced erk activation was not
significantly different between pkc sirnas and ctl sirna - transfected
vsmcs .
vsmcs were transfected with control ( ctl ) sirna or sigenome on - target
plus a set of four rat pkc sirnas ( dharmacon ) using lipofectamine 2000 .
a , representative western blot for expression of pkc and actin
after sirna transfection was shown .
b , the expression levels of
pkc after sirna transfection were measured by western blot and
normalized with its loading control ( actin ) .
data represent mean s.e .
from four independent experiments ( * , p < 0.05 ) .
c f , sirna - transfected and serumstarved vsmcs were stimulated
by 100 nm ang or 10 m sii for the indicated times
and cell lysates were analyzed for phosphorylated erk ( p - erk ) and
total erk ( erk ) .
c and e , representative p - erk and
erk western blots were presented for ang ( c ) and sii ( e )
stimulation .
d and f , signals were quantified by
densitometry and p - erk was normalized to a loading control ( erk ) .
signal at each
point is expressed as percentage of the maximal p - erk signal - stimulated ang
for 5 min in ctl sirna vsmcs .
d , statistical analysis was done using
a one - way anova ( prism software ) to correct for multiple comparisons
( bonferroni 's post test ) for ang - induced erk activation in pkc
sirna - transfected cells compared with ctl sirna - transfected cells at each time
point ( * p < 0.05 ) .
f , sii - induced erk activation was not
significantly different between pkc sirnas and ctl sirna - transfected
vsmcs .
in addition , sii - mediated erk activation was virtually completely abolished
by ag1478 as shown in fig . 6 , e
and f. because sii only activates
-arrestin - dependent pathways , this is clear evidence that egfr kinase
activity is required for -arrestin2-dependent erk activation in vsmcs .
our results utilizing rna interference and pharmacological inhibitors reveal
that -arrestin - dependent erk activation requires egfr kinase activity ,
suggesting that egfr transactivation is required for both g protein and
-arrestin2-dependent erk activation by at1r .
ang is known to induce transactivation of the egfr through activation of
metalloproteases that mediate cleavage of heparin - binding egf from its
precursor .
it has been reported that bips , previously known as matrix
metalloprotease-2/9 inhibitor , blocks ang - induced egfr transactivation
( 20 ) .
we examined the effect
of bips on sii - mediated erk activation in vsmcs .
pretreatment with bips
completely inhibits sii - induced erk activation ; whereas it inhibits
ang - induced erk activation by about 50%
( fig .
egf - induced erk activation is not affected by
pretreatment with bips ( data not shown ) .
furthermore , we observed that both
ang- and sii - induced dna synthesis were significantly inhibited by
pretreatment with ag1478 ( fig .
these data imply that erk activation stimulated by
ang in vsmcs may consist of several distinct components .
our data suggest that
the at1r - mediated g - protein- and -arrestin - dependent signaling pathways
converge by promoting egfr transactivation - dependent erk activation , which
results in vsmc proliferation .
role of src kinase in -arrestins - dependent erk
activation and egfr transactivation in recent years , src tyrosine
kinase has emerged as a key player in ang - mediated cellular effects including
the ras / erk activation pathway
( 21 ,
22 ) .
dominant negative mutants
of c - src lead to decreases in ang - induced erk activation in vsmcs
( 23 ) .
furthermore , it has been
reported that erk activation by ang is reduced in vsmcs derived from src
knock - out mice ( 24 ) .
therefore , we examined the function of src kinase on at1r - mediated ,
-arrestin - dependent erk activation in vsmcs .
fig . 7 , a and
b , shows that in the presence of pp2 , a src kinase
inhibitor , at1r - mediated erk stimulation by either ang or sii is significantly
reduced .
these levels are similar to those obtained with the egfr kinase
inhibitor , shown in fig .
6 , a and
e. these data demonstrate that both ang- and
sii - stimulated erk activation require src kinase activity
. we also found that
egf - mediated erk itself is sensitive to pp2 being reduced by 45% ( data not
shown ) .
this further suggests that at1r - mediated src kinase activation may
play multiple roles in regulating erk activation both prior to and/or
subsequent to egfr transactivation .
a f , vsmcs were transfected with control
( ctl ) or -arrestin2 sirnas using lipofectamine 2000 .
serum - starved vsmcs were pretreated with dimethyl sulfoxide ( dmso ) or 250
nm ag1478 and then stimulated with 100 nm ang or 10
m sii for the indicated times .
equal amounts of cell lysate
were separated by sds - page and analyzed for phosphorylated erk
( p - erk ) and total erk ( erk ) by western blotting .
signals
were quantified by densitometry and p - erk was normalized to a loading control
( erk ) .
signal at each point is expressed as percentage of the maximal p - erk
signal ( ang for 5 min ) in a dimethyl sulfoxide ( dmso)-treated ctl
sirna - transfected condition .
a and c , representative western
blots of p - erk and erk from ang - stimulated ctl sirna ( a ) and
-arrestin2 sirnas - transfected vsmcs ( c ) are presented .
b and d , data represent mean s.e . from six
independent experiments in panels
a and c. statistical
analysis was done using a one - way anova ( prism software ) to correct for
multiple comparisons ( bonferroni 's post test ) . * , p < 0.05
compared with the dimethyl sulfoxide - treated condition at each time point .
e , representative sii - induced p - erk and erk western blots from vsmcs
pretreated with dmso or ag1478 .
f , data represent mean s.e .
from six independent experiments . statistical analysis in each time point of
kinetic graphs
were determined by using a two - way anova ( bonferroni 's post
test ) between dimethyl sulfoxide and ag1478-treated cells ( * , p <
0.05 ) .
g and h , serum - starved vsmcs were pretreated with
dimethyl sulfoxide or 10m bips and then stimulated with 100
nm ang or 10 m sii for 5 min .
equal amounts of cell
lysate were separated by sds - page and analyzed for p - erk and erk by western
blotting .
signals were quantified by densitometry and p - erk was normalized to
a loading control ( erk ) .
signals at each condition were expressed as
percentage of the maximal p - erk obtained at 5 min for ang stimulation in
dmso - treated vsmcs .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's post
test ) . * , p < 0.05 , compared with the dmso - pretreated condition
for each stimulant .
i , vsmcs were serum starved for 24 h to arrest
cycling and pretreated with dimethyl sulfoxide or 250 nm ag1478 .
ang ( 100 nm ) or sii ( 10 m ) along with
h - labeled thymidine was then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean s.e . of fold - increase over basal
counts per minute ( cpm ) from four independent experiments .
statistical
analysis was done using a one - way anova ( prism software ) to correct for
multiple comparisons ( bonferroni 's post test ) .
the ag1478-pretreated condition
shows significant reduction compared with the dimethyl sulfoxide - pretreated
condition for each stimulant ( * , p < 0.05 ) .
ib ,
immunoblot . egfr - dependent activation of erk mediated by ang and sii
stimulation .
a f , vsmcs were transfected with control
( ctl ) or -arrestin2 sirnas using lipofectamine 2000 .
serum - starved vsmcs were pretreated with dimethyl sulfoxide ( dmso ) or 250
nm ag1478 and then stimulated with 100 nm ang or 10
m sii for the indicated times .
equal amounts of cell lysate
were separated by sds - page and analyzed for phosphorylated erk
( p - erk ) and total erk ( erk ) by western blotting .
signals
were quantified by densitometry and p - erk was normalized to a loading control
( erk ) .
signal at each point is expressed as percentage of the maximal p - erk
signal ( ang for 5 min ) in a dimethyl sulfoxide ( dmso)-treated ctl
sirna - transfected condition .
a and c , representative western
blots of p - erk and erk from ang - stimulated ctl sirna ( a ) and
-arrestin2 sirnas - transfected vsmcs ( c ) are presented .
b and d , data represent mean s.e . from six
independent experiments in panels
a and c. statistical
analysis was done using a one - way anova ( prism software ) to correct for
multiple comparisons ( bonferroni 's post test ) . * , p < 0.05
compared with the dimethyl sulfoxide - treated condition at each time point .
e , representative sii - induced p - erk and erk western blots from vsmcs
pretreated with dmso or ag1478 .
f , data represent mean s.e .
from six independent experiments . statistical analysis in each time point of
kinetic graphs
were determined by using a two - way anova ( bonferroni 's post
test ) between dimethyl sulfoxide and ag1478-treated cells ( * , p <
0.05 ) .
g and h , serum - starved vsmcs were pretreated with
dimethyl sulfoxide or 10m bips and then stimulated with 100
nm ang or 10 m sii for 5 min .
equal amounts of cell
lysate were separated by sds - page and analyzed for p - erk and erk by western
blotting .
signals were quantified by densitometry and p - erk was normalized to
a loading control ( erk ) .
signals at each condition were expressed as
percentage of the maximal p - erk obtained at 5 min for ang stimulation in
dmso - treated vsmcs .
statistical analysis was done using a one - way
anova ( prism software ) to correct for multiple comparisons ( bonferroni 's post
test ) . * ,
p < 0.05 , compared with the dmso - pretreated condition
for each stimulant .
i , vsmcs were serum starved for 24 h to arrest
cycling and pretreated with dimethyl sulfoxide or 250 nm ag1478 .
ang ( 100 nm ) or sii ( 10 m ) along with
h - labeled thymidine was then added to the media , and 24 h later
cells were harvested as described under experimental procedures .
results depicted represent the mean s.e . of fold - increase over basal
counts per minute ( cpm ) from four independent experiments .
statistical
analysis was done using a one - way anova ( prism software ) to correct for
multiple comparisons ( bonferroni 's post test ) .
the ag1478-pretreated condition
shows significant reduction compared with the dimethyl sulfoxide - pretreated
condition for each stimulant ( * , p < 0.05 ) .
proteins in the src tyrosine kinase family have been suggested previously
to function as upstream mediators of egfr transactivation , particularly in
response to the stimulation of 7tm receptors
( 25 ) .
thus we hypothesized
that src can be recruited to the at1r upon agonist binding by -arrestin2
and play a role in at1r - mediated egfr transactivation . to test this
hypothesis
, we examined the phosphorylation of egfr at tyr-845 upon ang and
sii stimulation in control or -arrestins sirna - transfected vsmcs .
this
site is known to be phosphorylated by src kinase
( 26 ) .
both ang and sii
significantly stimulate phosphorylation of egfr at tyr-845 in control cells
( fig .
interestingly , sii is equally effective as ang in
inducing phosphorylation at this site , which is a 1.9 0.2-fold
increase over basal .
both ang- and sii - induced egfr phosphorylation at tyr-845
is dramatically reduced by depletion of -arrestin2 expression by sirna .
on the contrary , depletion of -arrestin1 expression had no effect on
at1r - mediated phosphorylation of egfr ( data not shown ) .
consistent with other
findings , stimulation with the pkc activator phorbol 12-myristate 13-acetate
failed to induce phosphorylation of egfr on tyr-845 ( data not shown ) .
our
results suggest that -arrestin2 regulates at1r - mediated egfr
transactivation and subsequent erk activation by recruiting downstream
signaling molecules such as src kinase to the receptors .
figure 7.roles of src in ang- and sii - induced activation of erk and egfr .
a and b , vsmcs were pretreated with dmso or 10
m pp2 ( src inhibitor ) and then treated with 100 nm
ang or 10 m sii for 5 min .
equal amounts of cell lysate were
separated by sds - page and analyzed for phosphorylated erk ( p - erk ) and
total erk ( erk ) by western blotting .
signals were quantified by
densitometry and p - erk was normalized to a loading control ( erk ) .
signal at
each point is expressed as percentage of the maximal p - erk signal ( ang for 5
min ) in dimethyl sulfoxide ( dmso)-treated vsmcs . a ,
representative p - erk and erk western blots in dimethyl sulfoxide or
pp2-pretreated vsmcs were presented .
b , each data point represents
the mean s.e . from four independent experiments .
statistical analysis
was done using a one - way anova ( prism software ) to correct for multiple
comparisons ( bonferroni 's post test ) . * , p < 0.05 , compared with
dimethyl sulfoxide treatment for each stimulant .
c and d ,
vsmcs were transfected with the indicated sirnas using lipofectamine 2000 .
serum - deprived vsmcs were incubated with 100 nm ang and 10
m sii for 2 min and immunoprecipitated with egfr antibody .
egfr
phosphorylation was quantified by densitometry and normalized to a loading
control ( egfr ) .
c , representative western blots for
egfr and egfr in sirna - transfected vsmcs were presented .
d , data are presented as fold - increase over basal ( the mean
s.e . ) from six independent experiments .
statistical analysis was done using a
one - way anova ( prism software ) to correct for multiple comparisons
( bonferroni 's post test ) .
ang and sii significantly increase phosphorylation
of egfr at tyr-845 compared with no stimulation ( ns ) control ( * ,
p < 0.05 ) .
depletion of -arrestin2 shows a significant
reduction on both ang and sii mediated phosphorylation of egfr at tyr-845
compared with its own agonist stimulation in the control sirna - transfected
condition ( * * , p < 0.05 ) .
roles of src in ang- and sii - induced activation of erk and egfr .
a and b , vsmcs were pretreated with dmso or 10
m pp2 ( src inhibitor ) and then treated with 100 nm
ang or 10 m sii for 5 min .
equal amounts of cell lysate were
separated by sds - page and analyzed for phosphorylated erk ( p - erk ) and
total erk ( erk ) by western blotting .
signals were quantified by
densitometry and p - erk was normalized to a loading control ( erk ) .
signal at
each point is expressed as percentage of the maximal p - erk signal ( ang for 5
min ) in dimethyl sulfoxide ( dmso)-treated vsmcs . a ,
representative p - erk and erk western blots in dimethyl sulfoxide or
pp2-pretreated vsmcs were presented .
b , each data point represents
the mean s.e . from four independent experiments .
statistical analysis
was done using a one - way anova ( prism software ) to correct for multiple
comparisons ( bonferroni 's post test ) . * , p < 0.05 , compared with
dimethyl sulfoxide treatment for each stimulant .
c and d ,
vsmcs were transfected with the indicated sirnas using lipofectamine 2000 .
serum - deprived vsmcs were incubated with 100 nm ang and 10
m sii for 2 min and immunoprecipitated with egfr antibody .
egfr
phosphorylation was quantified by densitometry and normalized to a loading
control ( egfr ) .
c , representative western blots for
egfr and egfr in sirna - transfected vsmcs were presented .
d , data are presented as fold - increase over basal ( the mean
s.e . ) from six independent experiments .
statistical analysis was done using a
one - way anova ( prism software ) to correct for multiple comparisons
( bonferroni 's post test ) .
ang and sii significantly increase phosphorylation
of egfr at tyr-845 compared with no stimulation ( ns ) control ( * ,
p < 0.05 ) .
depletion of -arrestin2 shows a significant
reduction on both ang and sii mediated phosphorylation of egfr at tyr-845
compared with its own agonist stimulation in the control sirna - transfected
condition ( * * , p < 0.05 ) .
ang - mediated signaling in vsmcs plays important roles in the development of
pathological conditions such as restenosis , atherosclerosis , and hypertension .
abnormal regulation of 7tm receptor - mediated vsmc proliferation and migration
are the major forces inducing such pathological conditions in a variety of
vascular diseases
. mechanisms of vsmc proliferation induced by g protein
signaling induced by 7tm receptor systems have been extensively studied .
here
we investigated the novel roles of -arrestins in 7tm receptor - mediated
signaling in vsmcs .
classically , -arrestins terminate signals emanating
from agonist - bound 7tm receptors by physically interfering with receptor
coupling to its cognate g protein ( desensitization ) , and also removing
receptors from the cell surface through initiating interaction with several
elements of the clathrin - coated pit endocytic machinery ( internalization ) .
recent data , however , have revealed that -arrestins also act as signal
transducers and adaptors that scaffold a variety of signaling molecules ,
leading to mitogen - activated protein kinase activation , dna synthesis , protein
translation , and cell migration
( 2 ) .
roles of -arrestins as signal transducers have been extensively
studied for at1r - mediated erk activation in receptor - transfected hek 293 cells
( 13 ,
27 ) . here
, we studied
ang - stimulated erk activation in a physiologically relevant cell type , rat
vsmcs , and compared the results to those observed previously in hek 293 cells
transiently transfected with at1r . whereas , the overall patterns were similar ,
several notable differences were observed .
at1r - mediated erk activation in
vsmcs is more transient than that in at1r - transfected hek 293 cells . in the
latter ,
ang - stimulated erk activation reached maximal levels rapidly , remained
stable for up to 10 min , and decreased very slowly ( over 1 h )
( 13 ) . on the other hand , ang-
and sii - induced erk activation in vsmcs peaks at 5 min and is quite transient ,
decreasing to background levels by 30 min . this may be due to the very low
levels of endogenously expressed at1r in vsmcs ( 15 fmol / mg ) . by utilizing
-arrestin rnai and pkc inhibitors , two pathways for erk activation by
the at1r expressed in hek 293 cells
have been distinguished previously ; rapid
and transient g protein - dependent activation , which is sensitive to pkc
inhibitors versus slow and prolonged -arrestin2-dependent
activation , which is sensitive to -arrestin2 rnai
( 13 ) . in vsmcs , pretreatment
with pkc inhibitors
also specifically inhibits early activation of erk
( 12 min ) but not that at later time points , indicating that early
activation of erk requires g - protein - mediated second messenger production .
furthermore , depletion of -arrestin2 , but not of -arrestin1 , using
rnai leads to inhibition of ang - mediated erk activation at later time points
in vsmcs .
however , erk activation at later time points in vsmcs was not
completely abolished as was previously observed in at1r - transfected hek 293
cells , possibly due to incomplete depletion of -arrestin2 ( 70% ) in
primary cultured vsmcs .
functions of -arrestins as signal transducers have been demonstrated
for many different 7tm receptors including angiotensin ii type 1a
( at1a ) ( 13 ) ,
2-adrenergic
( 28 ) , neurokinin 1
( 29 ) , proteinase - activated
( 30 ) , vasopressin 2
( 31 ) , cxcr4 chemokine
( 32 ) , and parathyroid hormone
( 33 ) receptors , as well as for
other types of receptors including the insulin - like growth factor 1-receptor
( 34 ) , ion channels
( 35 ) , nicotinic acetylcholine
receptor ( 36 ) , and
transforming grow factor receptor
( 37 ) . in the case of 7tm
receptor - mediated erk activation , the later phase of -arrestin - dependent
erk activation is sometimes blocked by depletion of either -arrestin , by
depletion of -arrestin2 , but not -arrestin1 , or vice versa
depending on receptor and cell type . for example ,
both -arrestin1 and -2
are required for -arrestin - dependent erk activation mediated by
2-adrenergic
( 28 ) and parathyroid hormone
( 33 ) receptors . on the other
hand , -arrestin1 and -2
show reciprocal functions in at1r
( 27 ) and v2
( 31 ) receptor - mediated erk
activation ; -arrestin1 acts as a physiological
dominant - negative of -arrestin2-mediated erk activation by
these receptors . in the present study , ang - mediated erk activation in
-arrestin1 sirna - transfected vsmcs
was not enhanced compared with that
from control sirna - transfected cells except at the 2-min time point , and
sii - mediated erk activation was not changed in -arrestin1
sirna - transfected cells .
thus the role of -arrestin1 , if any , in
modulating -arrestin2-mediated erk activation stimulated via the at1r in
vsmcs is not clear .
at1r is a typical gq - coupled 7tm receptor that initiates
generation of inositol triphosphate and diacyglycerol second messengers by
activation of phosphatidylinositol - specific phospholipase c. these second
messengers in turn trigger mobilization of intracellular calcium and
activation of pkc , which has been known to play important roles in
at1r - mediated erk activation
( 14 ) . in vsmcs
, pkc has
been known to be activated upon ang stimulation leading to akt activation
( 38 ) and pkc has been
suggested to play a major role in at1r - mediated erk / elk-1 activation via the
ras / mek pathway ( 24 ) .
we
showed that inhibition of pkc activity using chemical inhibitors or by
depletion of its expression by rnai inhibited g protein - dependent ( early time
point ) at1r - mediated erk activation in vsmcs .
numerous 7tm receptors have been known to utilize egfr transactivation
mechanisms to activate erk in various cell types .
moreover , it has been
observed that at1r - mediated erk activation requires egfr kinase activity in
several cell types including c9 hepatocytes and cos-7 cells transfected with
the at1r as well as in vsmcs
( 19 ,
39 ) . it has been shown that g
protein activation plays a role in at1r - mediated egfr transactivation through
an heparin binding - egf shedding mechanism
( 40 ) .
here we found that the
-arrestin - biased analogue sii - ang induced erk activation and subsequent
dna synthesis also require egfr kinase activity in vsmcs .
moreover ,
sii - mediated erk activation was also inhibited in the presence of an matrix
metalloprotease inhibitor , which is known to block heparin binding - egf
shedding in vsmcs , suggesting that -arrestin2 as well as g proteins can
mediate an heparin binding - egf shedding mechanism in vsmcs . we also found that
stimulation with either ang or sii induced egfr phosphorylation at tyr-845 by
src kinase , which is known to activate egfr .
it has been shown that activation
of many 7tm receptors recruits activated c - src to the receptor complex in a
-arrestin - dependent manner
( 41 ) .
it thus appears that
multiple signaling mechanisms can mediate at1r and egfr cross - talk in vsmcs .
it will be of interest to determine whether distinct physiological outcomes of
at1r - mediated egfr transactivation are associated with these different
signaling mechanisms .
several physiologic consequences of -arrestin - dependent signaling
have been discovered in recent years .
for example , -arrestin - mediated
signal transduction via the at1r results in positive inotropic and lusitropic
effects in isolated adult mouse cardiomyocytes
( 42 ) .
-arrestin - dependent erk signaling regulates mrna translation and protein
synthesis via mnk1 , a protein that both physically interacts with and is
activated by -arrestin
( 43 ) .
1-adrenergic receptors have been shown to mediate
-arrestin - dependent transactivation of the egfr thus promoting
activation of the cardioprotective pathway in the heart that counteracts the
effects of catecholamine toxicity
( 44 ) .
in addition ,
atherosclerosis and restenosis in an animal model are aggravated by
-arrestin2 through mechanisms involving vsmc proliferation and migration
( 11 ) .
taken together , these
findings indicate the physiological and pathological importance of
-arrestins as transducers regulating mitogenic signals through 7tm
receptors . in summary , our findings indicate that for the atir in vsmcs g
protein - dependent second messenger - mediated and -arrestin2-dependent
signaling pathways converge on transactivation of the egfr and subsequent erk
activation .
these results underscore the complexity and
multiplicity of signaling mechanisms available to 7tm receptors and add to the
growing recognition of the importance of -arrestins as signal
transducers . | recent studies in receptor - transfected cell lines have demonstrated that
extracellular signal - regulated kinase ( erk ) activation by angiotensin type 1a
receptor and other g protein - coupled receptors can be mediated by both g
protein - dependent and -arrestin - dependent mechanisms .
however , few
studies have explored these mechanisms in primary cultured cells expressing
endogenous levels of receptors . accordingly
, here we utilized the
-arrestin biased agonist for the angiotensin type 1a receptor ,
sii - angiotensin ( sii ) , and rna interference techniques to investigate
angiotensin ii ( ang)-activated -arrestin - mediated mitogenic signaling
pathways in rat vascular smooth muscle cells .
both ang and sii induced dna
synthesis via the erk activation cascade . even though sii can not induce
calcium influx ( g protein activation ) after receptor stimulation , it does
cause erk activation , although less robustly than ang .
activation by both
ligands is diminished by depletion of -arrestin2 by small interfering
rna , although the effect is more complete with sii .
erk activation at early
time points but not later time points is strongly inhibited by those protein
kinase c inhibitors that can block protein kinase c. moreover , ang- and
sii - mediated erk activation require transactivation of the epidermal growth
factor receptor via metalloprotease 2/9 and src kinase . -arrestin2
facilitates ang and sii stimulation of src - mediated phosphorylation of tyr-845
on the egfr , a known site for src phosphorylation .
these studies delineate a
convergent mechanism by which g protein - dependent and
-arrestin - dependent pathways can independently mediate erk - dependent
transactivation of the egfr in vascular smooth muscle cells thus controlling
cellular proliferative responses . |
although humans achieve their needs , desires , and aspirations by working , human emotions might be influenced by numerous factors , including environmental and organizational factors which are not favorable ; so , the type of occupation of the person might be among the major stressors that can create a chronic stress . according to the definition of cooper , occupation stress is the result of interaction between the individual and the work environment .
job stress is one of the most important issues in the field of organizational behavior , and stress is a common disease of the 21 century .
it causes absenteeism , labor mobility and conflicts , physical disorders , and the high cost of health care .
stress is highly interrelated with all components of the health , safety , and convenience of the people .
lazarus and folkman define stress as a person 's reaction against the environment which , according to the same person , is a threat to the resources and his abilities .
all kinds of professions that are concerned with health and lives are always stressful , and they threaten the physical and mental health of practitioners .
icu nurses experience a high level of stress because of special circumstances arising from the work environment and the type of patients , severe disease , higher levels of knowledge and skills needed to work in this unit , and the need to respond quickly , promptly , and accurately to urgent situations .
mims and stanford , in their study , indicated that icu nurses are experiencing high level of job stress .
mohammad et al . revealed that 92% of nurses in critical units complain of disorders and stresses related to the workplace .
researchers are trying to identify the ways of dealing with a high level of job and occupational stress in nurses .
there are different medical , psychological , and psychiatric methods to deal with the problem . in recent decades
, some psychologists have presented new teaching therapeutic methods entitled neuro - linguistic programming ( nlp ) to deal with this problem .
this program emphasizes that human behavior stems from neurological processes , such that experience from the surrounding world leads to neuropsychological processes and guides practice .
nlp started in america in the 1970s from the collaboration of john grinder and richard bundler .
the term neurological denotes that all behaviors derive from the neurological processing of information provided by the five senses .
the linguistic part of the title refers to the fact that language is fundamental to the organization of thoughts and communication .
the term programming acknowledges the manner in which ideas and behaviors can be modified and managed to create desirable results .
nlp is a powerful instrument that accomplishes psychotherapy unbelievably , and it enables a person to decode the origin of individual words and speech . by doing this way , people feel , think , speak , and thus are capable of self - management and influencing others .
nlp seeks the relationship among thinking ( mental ) , speech ( linguistics ) , and behavior patterns ( behavior ) . instead of focusing on external stressful events ,
nlp focuses on individual reactions toward the stressful events , and it provides practical strategies to increase individual adaptation capacity and coping .
nlp deals with the structure of human experience subjectively , and it determines how one can organize what to see , hear , and feel , as well as how to purify one 's outside world through their senses .
his results showed that nlp was successful in treating fear ; in particular , too little time was needed to demonstrate the effectiveness of recovery .
however , despite the accounts of such methods designed to help patients who are resistant to a cure , there is little mention of cases where nlp has been completely ineffective in the literature .
it is likely that such cases do exist , as few therapies or treatments are universally successful .
however , deficiency of information in this area may be related to the lack of experimental evidence involving the use of nlp .
. showed that 75% of those who feared of mri could undergo it without fear and anxiety by the help of nlp . due to the obvious and damaging effects of stress on nurse 's physical psychiatric health and on the quality of nursing services
, it seems that applying the principles and practical solutions of nlp can increase the nurses adaptation capacity and improve their performance .
therefore , this study aimed to determine the effects of implementation of nlp strategies on job stress among icu nurses .
this study carried out as a quasi - experimental ( before after ) one with control and intervention groups . among nurses working in the critical care units of urmia imam khomeini and motahari educational
therapeutic centers , 16 volunteers participated in this survey ( 30 in the control group and 30 in the intervention group ) .
the inclusion criteria for the study included the following : volunteering to participate in the study , having a bachelor 's or higher degree in nursing , having a minimum of 6 months work experience in a special ward , not having a second job , not experiencing severe stress in the last 6 months ( severe accident , the death of a relative , marriage separation ) , and not having received psychotropic medication during the last 6 months . to access and analyze the professional stressors , the researchers applied the expanded nursing stress scale ( enss ) .
the enss is an expanded and updated version of the classic nursing stress scale ( nss ) developed by gray - taft and anderson ( 1981 ) .
enss contained 57 items in nine subscales : ( a ) death and dying , ( b ) conflict with physicians , ( c ) inadequate emotional preparation , ( e ) problems relating to peers , ( f ) problems relating to supervisors , ( g ) workload , ( h ) uncertainty concerning treatment , ( i ) patients and their families , and ( j ) discrimination .
the offered response options were does not apply ( 0 ) , never stressful ( 1 ) , occasionally stressful ( 2 ) , frequently stressful ( 3 ) , and extremely stressful ( 4 ) .
the response ( 0 ) indicated that the respondent had never faced the situation described by the item and , therefore , the final calculation of total score for this respondent was ( 0 ) .
calculation of the average value was performed by excluding zero values . the higher the score , the more the respondent agreed that the situation was stressful .
the total mean score could be derived from this instrument , which ranged from 0 to 228 .
there are no specific cut - off scores or published mean norms for the enss that determine whether an individual is stressed or not . however , higher scores indicate higher levels of stress . internal consistency reliability was assessed using cronbach 's coefficient alpha .
the 57-item enss showed improved reliability ( = 0.96 ) over the original nss ( = 0.89 ) .
individual subscale reliability ranged from = 0.88 ( problems with supervisors ) to = 0.65 ( discrimination ) .
the questionnaire was in this case cross - culturally adapted to meet the criteria of the research .
the instrument was translated into persian and back - translated ( from persian to english ) as a validity check .
a high degree of internal consistency was observed for each subscale using cronbach 's alpha values of 0.73 ( problems with peers ) to 0.91 ( ( problems with supervisors ) , and for the total scale , cronbach 's alpha value was 0.83 .
besides the enss scale , the researchers applied a supplementary questionnaire to obtain socio - demographic ( gender , age , marital status , number of children ) and work - related ( service length , night shift work , duties , employment status , and interest in nursing jobs ) data .
the nlp training program was designed as 18 three - hour ( in 6 months ) sessions held by a person trained for the experimental group in motahari hospital .
curriculum for training sessions of nero - linguistic program one month later , by redistributing the questionnaires among nurses in both groups ( control and experimental ) , their occupational stress was tested again .
descriptive statistics ( frequency , mean , and standard deviation ) and inferential statistics ( chi - square test , t - test , mann whitney test ) were used .
the study was approved by the research deputy and the research ethics committee of urmia university of medical sciences . before beginning the study ,
the researcher explained the objectives to the patients , and all participants signed a written informed consent before participation in the study .
the questionnaires were anonymous and all the participants were assured about the confidentiality of their personal information .
the researchers observed all ethical issues in accordance with the latest version of helsinki ethical declaration .
the study was approved by the research deputy and the research ethics committee of urmia university of medical sciences . before beginning the study ,
the researcher explained the objectives to the patients , and all participants signed a written informed consent before participation in the study .
the questionnaires were anonymous and all the participants were assured about the confidentiality of their personal information .
the researchers observed all ethical issues in accordance with the latest version of helsinki ethical declaration .
no significant differences were observed between the intervention and the control groups in terms of age , years of work experience , education , marital status , religion , employment status , work shift , interest in the job , and the number of children .
comparison of the demographic characteristics in the intervention and control groups in order to compare stress between the groups , mann
the results showed that there were no statistically significant differences between the groups in baseline mean stress scores ( p = 0.65 ) .
whitney test results showed that after the performance of nlp in the intervention group , there was a statistically significant difference in the mean stress scores of the two groups ( p = 0.0001 ) [ table 3 ] .
comparison of the average stress scores between the intervention and control groups before and after the implementation of strategies for teaching nlp table 4 shows that pre - interventionally , there was a significant difference ( p < 0.05 ) between the intervention and control groups concerning the scores of the subscales of death and dying , and problems with supervisors , patients and their families . in the subscales of conflict with physicians , lack of adequate emotional preparation , problems with colleagues , workload , uncertainty about treatment , and discrimination , there were no statistically significant differences ( p > 0.05 ) between the two groups before the intervention . however , there were statistically significant differences in all the subscales of stress between the intervention and control groups after implementing nlp training strategies in the intervention group ( p < 0.05 ) .
whitney test showed that there was a statistically significant difference ( p < 0.05 ) between the intervention and control groups concerning the mean scores of the subscales of death and dying , and problems with supervisors , patients and their families .
comparison of mean scores for each of the nine subscales of stress between the two groups before and after the implementation of intervention strategies of nlp training
the purpose of this study was to determine the effects of nlp learning strategies on the nurses job stress in the critical units .
the findings showed that in terms of demographic variables including age , work experience , employment , work , marital status , and number of children in the intervention and control groups , there was no statistically significant difference .
in other words , the control and intervention groups were homogeneous prior to the tutorial implementation ; thus , in the dependent variable of the experimental group , the statistically significant differences that were found were due to the positive impact of implementing nlp teaching strategies . in this study , most of the nurses had high stress level prior to the implementation of nlp teaching strategies . in the studies of preto and pedro in brazil ,
mohammad et al . at the university of alexandria of egypt , and mims and stanford at the university of west georgia in the usa , most of the nurses had high stress level . in all these studies , the work environment was reported to be stressful for icu nurses in terms of physical environment , pressure and volume of work , caring for ill and dying patients and their families , and observing the pain and suffering of the patients and their families .
the findings of this study showed that after the implementation of the nlp strategies , statistically significant differences were observed between the intervention and control groups in terms of stress , i.e. , the implementation of nlp had an impact on nurses job stress in the intervention group . moreover , the mean scores of job stress reduced in that group . in the process of teaching nlp , several strategies such as goal setting ,
time management , assertiveness skills , effective communication , and representation systems had been taught to the nurses .
learning these strategies created diverse variations in the personal and interpersonal indicators . by learning these strategies ,
the nurses had a realistic perception of themselves and the world around ; moreover , they adjusted their personal feelings and beliefs , and controlled their emotions and behaviors . by learning these techniques
, they had a purposeful life , a significant effort toward their designated goals , and an effective communication skill with others .
they enhanced their ability to control themselves and others , and had a positive attitude toward self and others .
no similar study has been conducted about the influence of nlp on job stress , while many studies have examined the impact of nlp on various topics .
harman and oneill found in their study that consultants using representation systems can contact their clients more easily by using the meta - model ( one of the techniques of nlp ) .
prentice conducted a research to investigate the changes in achievement motivation ; he noted that using self - regulatory strategies ( time management and goal - setting skills ) and general life skills ( assertiveness skills ) can push the learners toward their goals , and it can increase their motivation .
biggs showed in his study that awareness of the nlp and meta - model enhanced the ability of teachers to interact with their students , and it caused the failed students to achieve greater success in the lessons ; furthermore , knowledge of nlp allowed the teachers to control things from different perspectives .
. performed an experimental study on the effectiveness of neuro - liguistic psychotherapy on patients with depression .
the researchers concluded that the effect of nlp is like that of previously approved methods such as cognitive behavioral therapy .
his results showed that in a short time , nlp was successful in treating fear .
. showed that 76% of those who fear of mri can complete it without fear and anxiety after applying nlp .
nlp can reduce anxiety ; subsequently , it allows mri to be performed without resorting to general anesthesia in a high proportion of claustrophobic adults .
sorensen et al . , in their study of weight control programs through nlp , showed that it is an effective method of weight control .
scheemeister investigated and approved the effect of teaching nlp strategies on students academic motivation and performance .
kamp used nlp techniques in his study to increase confidence and showed that it is very effective in increasing self - confidence .
from the perspective of nlp , human interpretation of environmental conditions can cause stress . by recognizing the mental and verbal processes that have a direct impact on thinking and behavior , it is essential to change perceptions , and finally change and modify undesirable behaviors . using nlp strategies has changed subjective perceptions and impressions , and has caused a more positive attitude toward the problems .
in this study , the researchers applied various strategies including goal setting and time management , assertiveness skills , belief changing techniques , reforming and reframing techniques , communication skills , understanding of the neurological level , and disney strategy among nurses of the intervention group . by applying these techniques , changing beliefs and modifying adverse and stressful behaviors became possible .
nurses were more capable of coping with stressful situations by applying more targeted and effective time management skills to achieve their personal and social desirability .
also , by using assertiveness skills effectively and by an effective communication with self and others , changing the frames of mind , and controlling the words used in everyday life , nurses were capable of adapting themselves with stressful situations . by using nlp ,
teachers are expected to increase and strengthen the social interactions of nurses facing stressful events . with this technique
, they could comfortably establish effective communication with their patients , families , and colleagues . | background : the use of coping strategies in reducing the adverse effects of stress can be helpful .
nero - linguistic programming ( nlp ) is one of the modern methods of psychotherapy .
this study aimed to determine the effect of nlp on occupational stress in nurses working in critical care units of urmia.materials and methods : this study was carried out quasi - experimentally ( before after ) with control and experimental groups . of all the nurses working in the critical care units of urmia imam khomeini and motahari educational / therapeutic centers , 60 people participated in this survey .
eighteen sessions of intervention were done , each for 180 min .
the experimental group received nlp program ( such as goal setting , time management , assertiveness skills , representational system , and neurological levels , as well as some practical and useful nlp techniques ) .
expanding nursing stress scale ( enss ) was used as the data gathering tool .
data were analyzed using spss version 16 .
descriptive statistics and chi - square test , mann whitney test , and independent t - test were used to analyze the data.results:the baseline score average of job stress was 120.88 and 121.36 for the intervention and control groups , respectively ( p = 0.65 ) .
after intervention , the score average of job stress decreased to 64.53 in the experimental group while that of control group remained relatively unchanged ( 120.96 ) .
mann
whitney test results showed that stress scores between the two groups was statistically significant ( p = 0.0001).conclusions : the results showed that the use of nlp can increase coping with stressful situations , and it can reduce the adverse effects of occupational stress . |
chronic urticaria not responding to high - dose antihistamines is a therapeutic challenge , and in such cases other systemic treatment options should be considered .
the literature is scarce in defining effective immunosuppressive drugs that may be used for long - term treatment .
systemic corticosteroids are usually effective but are not feasible as maintenance therapy , and other immunosuppressive drugs such as azathioprine , methotrexate , oral tacrolimus , and mycophenolate mofetil have only been used in case reports or small patient series . in two
randomised , double - blind , and placebo - controlled trials cyclosporine a was found to be effective in controlling recalcitrant chronic urticaria [ 4 , 5 ] .
finally , recent reports also point to omalizumab , a recombinant monoclonal antibody that inhibits the high - affinity fc receptor of ige , as an effective agent in patients with refractory chronic urticaria [ 68 ] .
tumour necrosis factor alpha ( tnf - alpha ) inhibitors have so far only been used to treat a total of eight patients with chronic urticaria according to available publications [ 911 ] . here
we present our experience in 20 adult patients with severe refractory chronic urticaria who were received with either adalimumab or etanercept and thereby significantly expand our knowledge of the use of tnf - alpha inhibitors for this indication .
the patients described herein were a retrospective sample of patients with chronic urticaria ( duration of urticaria ranged from seven months to 46 years with a mean of 13 months ) seen in the outpatient clinic of a tertiary dermatological referral centre .
twenty adult patients with severe chronic urticaria with or without angioedema that was refractory to high - dose antihistamines and at least one immunosuppressive agent were offered off - label monotherapy with either adalimumab 40 mg twice monthly or etanercept 50 mg once weekly . for the main part of the patients , adalimumab
was chosen over etanercept as first choice therapy , but this choice was not based on a predefined belief of superiority of this drug over the other .
previous therapy with high dose antihistamines up to four times daily of cetirizine 10 mg , loratadine 10 mg , desloratadine 5 mg , or fexofenadine 180 mg , prednisolone up to 25 mg once daily , azathioprine up to 100 mg daily , cyclosporine a up to 3 mg / kg daily , mycophenolate mofetil up to 500 mg twice daily , dapsone up to 50 mg twice daily , colchicine up to 0.5 mg twice daily , or omalizumab 300 mg once every four weeks was either ineffective or associated with unacceptable side effects , and therefore alternative therapy was considered appropriate .
urticaria patients were screened for signs of systemic disease or chronic infection with a clinical interview , and urine analysis and culture , throat swab for streptococci , and an ice cube test for cold - induced urticaria were performed .
further evaluations were performed as appropriate including urea breath test for the diagnosis of helicobacter pylori , stool culture , chest and sinus x - rays , and skin prick tests for common aero- or food - allergens .
blood samples were taken including complete blood count , electrolytes , thyroid stimulating hormone , antinuclear antibodies , c - reactive protein , hepatitis b and hepatitis c screening , immunoglobulins a , e , g , and m , and kidney and liver function .
furthermore , a serum - induced basophil histamine release test , hr - urticaria test , was performed ( reflab , copenhagen , denmark ) .
if the hr - urticaria test was found positive ( > 16.5% of total histamine content ) , patients were categorised as having chronic autoimmune urticaria ( cau ) . in total , only two patients had cau . if the hr - urticaria test was found negative ( < 16.5% of total histamine content )
one patient was diagnosed with neutrophilic urticaria ( nu ) , whereas one patient was diagnosed with delayed pressure urticaria ( dpu ) , respectively , based on a typical clinical and symptomatic appearance .
a total of seven patients with csu also presented with a concomitant history of angioedema ( ae ) .
the patients were followed up in our outpatient clinic one month after initiating therapy with tnf - alpha inhibitors , and thereafter every third month , unless side effects occurred or treatment was unsuccessful . at each visit ,
based on retrospective patient records , it was possible to score the clinical response to treatment with tnf - alpha inhibitors for each patient as complete or almost complete resolution , partial resolution , ( > 50% reduction in symptoms and signs ) , and no / limited response .
furthermore , the duration of therapy and any signs of adverse effects of adalimumab and etanercept were recorded .
a total of 12 patients ( 60% ) obtained resolution of urticaria and/or angioedema after initiation of therapy with either adalimumab or etanercept ( table 1 ) .
none of the patients worsened during treatment , but five patients had no benefit from the treatment .
these patients were not offered treatment with another tnf - alpha inhibitor . among responders , response to treatment was observed within the first month after initiating therapy with either adalimumab or etanercept .
however , to achieve long - term relief of urticaria symptoms , continuous treatment with tnf - alpha inhibitors was needed , as intermission led to return of symptoms within a few weeks .
therefore , therapy with tnf - alpha inhibitors was not regarded as curative . the duration of treatment among responders ranged between three and 30 months with a mean of 11 months .
patients were allowed to continue antihistamines during treatment with tnf - alpha inhibitors . however , the patients who had benefit from treatment were able to reduce or discontinue antihistamines .
six patients ( 30% ) developed adverse reactions during treatment with adalimumab or etanercept . in five patients ,
these were restricted to increased frequency of mild upper respiratory infection not requiring antibiotics or hospitalization , whereas one patient , a 31-year - old female , was hospitalized due to severe headache , dizziness , vertigo , and decreased muscle strength of the upper extremities three months after initiating treatment with adalimumab . in this patient
a lumbar puncture showed cerebrospinal lymphocytosis and increased protein concentration indicating a cns toxic reaction .
however , an mr scan of the cerebrum did not reveal any abnormalities and her symptoms gradually disappeared within six months following discontinuation of adalimumab .
among 20 patients with chronic urticaria who were unresponsive to treatment with high - dose antihistamines and one or more standard immunosuppressive therapies , we observed complete or almost complete resolution of symptoms in 60% and partial resolution in a further 15% of the patients with the tnf - alpha inhibitors adalimumab or etanercept .
responders had csu or cau with and without angioedema , whereas patients with dpu or nu did not respond to treatment with tnf - alpha inhibitors .
it is of interest that five of the 12 patients who had significant improvement with tnf - alpha inhibitors previously had failed treatment with omalizumab due to lack of efficacy or an anaphylactoid reaction .
we and others have recently shown that omalizumab is effective in a significant proportion of patients with severe chronic urticaria [ 68 ] , but this study clearly indicates that a subgroup of patients who can not be sufficiently treated with omalizumab may obtain resolution of symptoms with a tnf - alpha inhibitor . however , it is our present position that the preferred therapy for chronic recalcitrant urticaria not responding to high - dose antihistamines and/or standard immunosuppressive drugs should be omalizumab , and that tnf - alpha inhibitors should be recommended as a second - line therapeutic option .
this is based primarily on the observation that omalizumab , in comparison with tnf - alpha inhibitors for this indication , has significantly fewer adverse effects during prolonged treatment , and with a more sustained and reliable efficacy .
a literature search identified three publications including a total of eight patients with chronic urticaria who have received monotherapy with tnf - alpha inhibitors [ 911 ] .
treatment of one patient with cold urticaria and one patient with dpu was successful .
in one small series of six patients with refractory csu and chronic urticarial vasculitis , therapy with etanercept , adalimumab , or infliximab resulted in marked rapid improvement in all patients .
the pathogenesis of chronic urticaria involves mediator release , including tnf - alpha , which exists preformed in the mast cells and which is known to be newly synthesized upon mast cell activation .
the theoretical basis for the use of tnf - alpha targeting therapy is supported by a study that has shown that tnf - alpha is upregulated in patients with chronic urticaria compared with healthy controls .
in addition it has been shown that tnf - alpha is expressed throughout the epidermis in both lesional and nonlesional skin of patients with chronic urticaria but not in healthy controls .
interestingly the cytokine profile in the skin of patients with chronic urticaria mimics that found in patients with psoriasis , psoriatic arthritis , and rheumatoid arthritis with increased expression of tnf - alpha and il-10 and decreased expression of il-2 and interferon gamma . in conclusion
this study suggests that tnf - alpha inhibitors could be considered in patients with severe chronic urticaria where other treatment options are contraindicated have been unsuccessful or have been associated with unacceptable adverse reactions . as this was only a small explorative cohort with no prespecified primary outcome , validated scoring system of response to treatment , or treatment algorithm for adalimumab and etanercept , it was not possible to draw any firm conclusions about superiority of one drug over the other , selective response in any urticaria subtype or with certain clinical , or paraclinical characteristics . this is a limitation of the study .
larger controlled trials with longer followup are needed to confirm the efficacy and safety of tnf - alpha inhibitors in the management of patients with severe chronic urticaria . | patients with severe chronic urticaria may not respond to antihistamines , and other systemic treatment options may either be ineffective or associated with unacceptable side effects .
we present data on efficacy and safety of adalimumab and etanercept in 20 adult patients with chronic urticaria .
twelve ( 60% ) patients obtained complete or almost complete resolution of urticaria after onset of therapy with either adalimumab or etanercept .
further three patients ( 15% ) experienced partial response .
duration of treatment ranged between 2 and 39 months .
those responding completely or almost completely had a durable response with a mean of 11 months .
six patients ( 30% ) experienced side effects and five patients had mild recurrent upper respiratory infections , whereas one patient experienced severe cns toxicity that could be related to treatment with tnf - alpha inhibitor .
adalimumab and etanercept may be effective and relatively safe treatment options in a significant proportion of patients with chronic urticaria who do not respond sufficiently to high - dose antihistamines or in whom standard immunosuppressive drugs are ineffective or associated with unacceptable side effects . |
we set up a double - blind , randomised study that administered either
chloroquine or placebo ( starch ) to patients suspected of having dengue disease .
patients were included in the study if they presented with dengue - related symptoms ,
such as fever and at least two other symptoms , such as headache , retro - orbital pain ,
muscle and bone or joint pain , nausea , vomiting and rash , for less than 72 h.
patients were excluded if they were pregnant , younger than 18 years old or had
either cardiac or neurologic disease .
once entered into the study , the patients were
randomised in a double - blind fashion to receive either 500 mg chloroquine ( 300 mg
base ) bid or an identical - appearing placebo bid for three days ( control group ) . in
addition to the use of either chloroquine or placebo ,
both groups were similarly
treated with hydration and symptomatic medication , such as analgesic and antipyretic
drugs , according to medical prescription .
three diagnostic tests were performed according to well - defined protocols
[ reverse transcription - polymerase chain reaction , igm antibody capture elisa and the
non structural 1 ( ns1 ) antigen detection ] on all the samples ( innis et al .
the patients were
re - evaluated one week later and clinical data associated with dengue symptoms , such
as fever , headache , retro - orbital pain , muscle , bone or joint pain , nausea and
vomiting were recorded as well as symptoms related to the side effects of
chloroquine . the axillary temperature was objectively measured and considered
abnormal ( fever ) when 37.8c .
other variables were obtained actively and
objectively during a medical consultation using a research form .
the study
was approved by the ethical committee of the clinical hospital of the school of
medicine of ribeiro preto , university of so paulo , process 12603/2006 , and written
informed consent was obtained from all participants .
the data are presented as the means standard deviations and number of
patients ( % ) .
differences between the two study groups were assessed using an
unpaired t test for continuous outcomes and fisher 's exact test for
proportions .
all p values were two - sided and all analyses were performed with the
use of graphpad software , version 3.05 ( graphpad software , san diego , ca , usa ) .
the study was conducted from mid - february to the first week of may of
2008 .
one hundred thirty - two patients were assessed for eligibility : three did not
meet the inclusion criteria and 129 underwent randomisation .
the patients enrolled
in the study were adults ( mean age , 31.64 11.74 years ) , were predominantly female
( 51.2% ) and reported a mean average duration of symptoms of 41.52 20.16 h. of the
129 patients , 63 were randomised to receive chloroquine and 66 were randomised to
receive placebo .
seventy - five patients had other febrile diseases ( ofds ) and 54 were
confirmed to have dengue . of the dengue patients ,
of these patients , 19 received chloroquine ( mean age , 32.72
11.50 years ; male , 42% ; duration of symptoms , 1.94 0.90 day ) and 18 patients
received placebo ( mean age , 36.74 11.83 years ; male , 56% ; duration of symptoms ,
1.56 0.73 day ) .
no patient exhibited the severe form of the disease ( dengue
haemorrhagic fever ) and/or shock ( dengue shock syndrome ) ( table ) .
there was no significant difference between group
characteristics ( p > 0.05 ) and the most frequent symptoms were fever ( 100% ) , body
ache ( 99.2% ) , headache ( 96.8% ) , joint pain ( 70.4% ) and retro - orbital pain ( 68% ) .
there was no significant difference in the duration of the disease or the intensity
and days of fever among the dengue patients treated with either chloroquine or
placebo . however , 12 ( 63% ) of the dengue patients reported a substantial reduction
in the intensity of pain and a great improvement in their ability to perform daily
chores after taking chloroquine , whereas no improvement was reported by the patients
taking placebo ( p = 0.0004 ) ( table ) .
however , as this finding was not observed in the patients with ofds , which included
bacterial pneumonia , urinary tract infection and influenza , these diseases were not
included in the statistical evaluation because the primary goal of this study was to
examine the influence of chloroquine on the evolution of dengue disease .
interestingly , the symptoms returned immediately after the patients stopped taking
the three - day chloroquine treatment , showing that chloroquine 's effect was most
likely due to the anti - inflammatory action of chloroquine rather than to its
antiviral effect .
tablecharacteristics of dengue patients treated with
chloroquine ( 300 mg base ) bid or identical - appearing placebo bid for
three days chloroquine group control group patients ( n ) 19 18 age ( years ) ( mean sd ) 32.72 11.50 36.74 11.83
gender ( male ) [ n ( % ) ] 8 ( 42 ) 10 ( 56 )
symptoms onset ( days ) ( mean sd ) 1.94 0.90 1.56 0.73
fever [ n ( % ) ] 19 ( 100 ) 18 ( 100 )
improvement in the intensity of pain and on ability to
perform daily chores [ n ( % ) ]
12 ( 63 ) 0 ( 0 )
a : dengue was confirmed when at least two diagnostic tests ( reverse
transcription - polymerase chain reaction , igm antibody capture elisa
and the non structural 1 antigen detection ) were positive ; b : p
> 0.05 ; c : axillary temperature was considered abnormal ( fever )
when 37.8c ; d : clinical variables were obtained active and
objectively during a medical consultation by using a research form ;
e : p = 0.0004 ; sd : standard deviation .
a : dengue was confirmed when at least two diagnostic tests ( reverse
transcription - polymerase chain reaction , igm antibody capture elisa
and the non structural 1 antigen detection ) were positive ; b : p
> 0.05 ; c : axillary temperature was considered abnormal ( fever )
when 37.8c ; d : clinical variables were obtained active and
objectively during a medical consultation by using a research form ;
e : p = 0.0004 ; sd : standard deviation .
side effects were reported by only two patients and consisted of
transient blurred vision in one and a loss of consciousness in the other .
the latter
patient was severely dehydrated and seizure was ruled out based on clinical
presentation and follow - up .
chloroquine did not alter the duration of the disease or the intensity
and days of fever compared to the dengue patients taking placebo .
however , the
patients taking chloroquine reported a substantial reduction in the intensity of
pain and a great improvement in their health status .
dengue is a worldwide health problem that affects millions of people and
causes innumerable deaths , particularly in the tropical and subtropical areas of the
world .
controlling the viral vector is currently the only option for reducing dengue
disease rates , as there is no a vaccine or effective antiviral agent available for
the treatment of dengue infections .
accordingly , it is important to identify
treatment strategies that could reduce the burden of this disease ( valero & levy 2008 ) .
chloroquine is a 9-aminoquinoline known since 1934 that has a long
history of use as an antimalarial agent and as an alternative drug to treat a
variety of chronic diseases ( savarino et al .
the rationales for using chloroquine in dengue patients include
the drug 's anti - inflammatory property , possible antiviral effect , with action on
flaviviruses , low cost , universal availability and safety and global public health
importance of dengue .
recently , a potential use of chloroquine has been described in
some viral infections , such as influenza , human immunodeficiency virus and severe
acute respiratory syndrome ( coronavirus ) ( lanciotti
et al .
one possible explanation for the antiviral effect of chloroquine could be
related to the impairment of viral replication by raising the intracellular ph and
thereby interfering with endosome - mediated viral entry .
an increase in ph in acidic
organelles , including endosomes , lysosomes and golgi vesicles , leads to unwanted
changes in the post - translational modifications of newly synthesised proteins ,
particularly the inhibition of glycosylation ( savarino et al .
these effects are of particular importance in denv infection
because these viruses require endosomal acidification to release their viral rna in
the cytoplasm to initiate viral replication ( lindenbach & rice 2003 ) .
other possible antiviral actions of
chloroquine are based on either interference with the post - translational processing
of viral glycoproteins , leading to imperfect glycosylation or to undefined
interference with the late stages of viral replication ( savarino et al .
however , the exact mechanism of action of chloroquine has not
been completely elucidated and differs depending on different pathogens ( rolain et al . 2007 ) .
( 2010 ) evaluated the effect of
chloroquine in hospitalised adult patients with dengue and found no difference in
viraemia or ns1 antigenaemia duration and modest anti - pyretic activity for
chloroquine in the intention - to - treat population , but not in dengue
laboratory - confirmed cases .
moreover , these researchers observed a trend toward a
lower incidence of dengue haemorrhagic fever in dengue patients treated with
chloroquine . in our study , there was also no difference in the duration of disease or
days of fever in dengue patients taking either chloroquine or placebo .
however , the
patients taking chloroquine in addition to routine analgesic drugs had a substantial
reduction in the intensity of pain and a great improvement in health status .
the
pain amelioration observed in the enrolled patients taking chloroquine was not
quantified by pain scales , which is a limitation of our study .
however , we
objectively inquired about and evaluated the dengue - related symptoms , including
pain , in all patients during acute disease and one week later , at the time when the
patients returned for a clinical evaluation during convalescence .
we hypothesised that the clinical benefit observed in dengue patients
treated with chloroquine could be due to the drug 's anti - inflammatory effects ,
particularly because chloroquine is a tumour necrosis factor ( tnf)- inhibitor and
some of the clinical manifestations in dengue patients are due to high levels of
serum tnf- ( hober et al .
another possible effect of chloroquine
in dengue patients could be related to its antiviral action , lowering the viral load
and thus the degree of immune system activation .
other studies with different
therapeutic doses , different durations and an earlier onset of treatment should be
performed to evaluate the in vivo effect of chloroquine on dengue infection .
moreover , it would be interesting to compare the effect of other anti - inflammatory
compounds on the treatment of dengue patients ; however , non - steroidal drugs should
be avoided in the care of these patients .
one limitation of this study was the small number of patients treated
with chloroquine .
although only a small number of dengue patients were included in
the study , approximately 63% reported an improvement in their symptoms while on the
medication and the symptoms returned immediately after the patients stopped taking
the medication .
this finding indicates that chloroquine is a possible candidate for
use in the treatment of dengue . in addition , the side effects of chloroquine
observed in this study were unremarkable .
adverse effects , such as headache , nausea , malaise , dizziness , blurred
vision , difficulty focusing , mild gastrointestinal upset and pruritus , may commonly
occur .
severe toxicity , e.g. , neuromyopathy , retinopathy and bone - marrow toxicity ,
is rare and may occur with long - term treatment and/or as an idiosyncratic reaction (
taylor & white 2004 , alkadi 2007 ) .
acute toxicity
is most frequently found with therapeutic or high doses administered too rapidly by
parenteral routes ( alkadi 2007 ) .
toxic
effects are related to the ingested dose and a single dose of 20 mg / kg is considered
toxic ( taylor & white 2004 ) . in this
study ,
a safety dose of 600 mg per day for three days was used in adults and the
side effects were unremarkable . furthermore , the chloroquine dosage used in this
study is very similar to the dosage used for vivax malaria treatment and , in our
experience , side effects are rare with this treatment .
however , considering the
small number of patients , more studies are necessary to evaluate the safety of
chloroquine in dengue patients . in conclusion , chloroquine promoted a reduction in the intensity of pain
and an improvement in the well - being of patients with dengue infection , but did not
alter the duration of the disease or the intensity and days of fever .
therefore ,
considering that the current options for dengue treatment are very limited , we
suggest that chloroquine should be further tested in dengue disease with a larger
number of patients and different chloroquine dosages and times of administration to
confirm the drug 's clinical effect and to assess the side effects of chloroquine in
dengue patients . | dengue is the most important arboviral disease in the world .
as
chloroquine , an antimalarial agent , has shown some antiviral effects , this study
evaluated its effect in patients with dengue .
a randomised , double - blind study
was performed by administering chloroquine or placebo for three days to 129
patients with dengue - related symptoms . of these patients ,
37 were confirmed as
having dengue and completed the study ; in total , 19 dengue patients received
chloroquine and 18 received placebo .
there was no significant difference in the
duration of the disease or the degree and days of fever . however , 12 patients
( 63% ) with confirmed dengue reported a substantial decrease in pain intensity
and a great improvement in their ability to perform daily activities ( p =
0.0004 ) while on the medication and the symptoms returned immediately after
these patients stopped taking the medication .
the same effect was not observed
in patients with diseases other than dengue .
therefore , this study shows that
patients with dengue treated with chloroquine had an improvement in their
quality of life and were able to resume their daily activities .
however , as
chloroquine did not alter the duration of the disease or the intensity and days
of fever , further studies are necessary to confirm the clinical effects and to
assess the side effects of chloroquine in dengue patients . |
in addition to making phone calls , users are able to play games , chat with friends , use messenger systems , access web services ( e.g. , blogs , homepages , social networks ) , and search for information . given their convenience and variety of functions , smartphones are widely popular , and the number of users is rapidly increasing , with more than 1.08 billion users across the globe in early 2012 ( mok et al . , 2014 ) .
in south korea , the number of smartphone users was estimated to be upwards of 39 million ( ministry of science , information and communications technology and future planning , 2014 ) .
excessive smartphone use can interfere with concentration at school or work and can cause physical difficulties , such as neck stiffness , blurred vision , wrist or back pain , and sleep disturbances ( kim & kang , 2013 ; korea internet & security agency , 2011 ; kwon et al .
it can also reduce in - person social interaction and academic achievement and lead to relationship problems ( kim & kang , 2013 ; kuss & griffiths , 2011 ; mok et al . ,
studies on smartphone use ( korea internet & security agency , 2013a ) have shown that among smartphone users , 45.8% feel anxiety when they are not holding their smartphone , 27.1% spend too much time using their smartphone , and 22.6% have repeatedly attempted to reduce their smartphone use but have always failed . moreover , 21.0% of smartphone users reported difficulties with school or work due to excessive smartphone use .
further , these percentages were higher for individuals in their teens and twenties . considering that addiction is a phenomenon characterized by tolerance , withdrawal symptoms , dependence , and social problems ( holden , 2001 ; kim , 2006 ; kwon et al . , 2013 ; obrien , 2011 ) ,
although smartphone addiction is a relatively new concept and not included in the most recent version of the diagnostic and statistical manual for mental disorders ( dsm-5 ; american psychiatric association , 2013 ) , research studies and social interventions have been conducted to address the adverse impact of smartphone addiction . in south
korea , the smartphone addiction scale was developed to assess the severity of smartphone addiction ( kwon et al . , 2013 ) , and a number of public institutions ( e.g. , ministry of science , information and communications technology and future planning ; korea internet & security agency ; korea communications commission ) have been frequently reporting research data on smartphone use ( kim et al .
2014 ) . in order to understand smartphone addiction , knowledge of the risk and protective factors for such addiction is essential .
findings indicate that males are more vulnerable to internet addiction than are females ( fattore , melis , fadda & fratta , 2014 ; heo , oh , subramanian , kim & kawachi , 2014 ) .
moreover , a recent meta - analysis showed that internet addiction was significantly associated with alcohol abuse , depression , and anxiety ( ho et al . , 2014 ) .
another study reported that depression , alcohol use , and smoking were important predictors of internet addiction ( chang , chiu , lee , chen & miao , 2014 ) . given that smartphones are based on the internet , we assumed that smartphone addiction might share many social or psychological properties with internet addiction .
considering the findings described above , gender , alcohol use , smoking , anxiety , and depression were adopted as hypothesized risk variables in our study . as hypothesized protective factors , character strengths and resilience
the concept of character strength is often used in positive psychology and includes virtues such as wisdom and courage ( kim , yoon , kwon & ha , 2010 ) .
resilience refers to a person s ability to maintain psychological wellbeing and adapt successfully to acute stress , trauma , or more chronic forms of adversity ( jung et al . , 2012 ) .
resilience is a multidimensional construct that includes temperament , personality , and specific skills ( jung et al . , 2012 ) and is negatively associated with the pathophysiology of addictive disorders ( russo , murrough , han , charney & nestler , 2012 ) .
the aim of this study was to assess the risk and protective factors associated with smartphone addiction and to compare these factors with those linked to internet addiction .
in addition to making phone calls , users are able to play games , chat with friends , use messenger systems , access web services ( e.g. , blogs , homepages , social networks ) , and search for information . given their convenience and variety of functions , smartphones are widely popular , and the number of users is rapidly increasing , with more than 1.08 billion users across the globe in early 2012 ( mok et al . , 2014 ) .
in south korea , the number of smartphone users was estimated to be upwards of 39 million ( ministry of science , information and communications technology and future planning , 2014 ) .
excessive smartphone use can interfere with concentration at school or work and can cause physical difficulties , such as neck stiffness , blurred vision , wrist or back pain , and sleep disturbances ( kim & kang , 2013 ; korea internet & security agency , 2011 ; kwon et al .
it can also reduce in - person social interaction and academic achievement and lead to relationship problems ( kim & kang , 2013 ; kuss & griffiths , 2011 ; mok et al . ,
studies on smartphone use ( korea internet & security agency , 2013a ) have shown that among smartphone users , 45.8% feel anxiety when they are not holding their smartphone , 27.1% spend too much time using their smartphone , and 22.6% have repeatedly attempted to reduce their smartphone use but have always failed . moreover , 21.0% of smartphone users reported difficulties with school or work due to excessive smartphone use .
further , these percentages were higher for individuals in their teens and twenties . considering that addiction is a phenomenon characterized by tolerance , withdrawal symptoms , dependence , and social problems ( holden , 2001 ; kim , 2006 ; kwon et al . , 2013 ; obrien , 2011 ) ,
although smartphone addiction is a relatively new concept and not included in the most recent version of the diagnostic and statistical manual for mental disorders ( dsm-5 ; american psychiatric association , 2013 ) , research studies and social interventions have been conducted to address the adverse impact of smartphone addiction . in south
korea , the smartphone addiction scale was developed to assess the severity of smartphone addiction ( kwon et al . , 2013 ) , and a number of public institutions ( e.g. , ministry of science , information and communications technology and future planning ; korea internet & security agency ; korea communications commission ) have been frequently reporting research data on smartphone use ( kim et al .
2014 ) . in order to understand smartphone addiction , knowledge of the risk and protective factors for such addiction is essential .
findings indicate that males are more vulnerable to internet addiction than are females ( fattore , melis , fadda & fratta , 2014 ; heo , oh , subramanian , kim & kawachi , 2014 ) .
moreover , a recent meta - analysis showed that internet addiction was significantly associated with alcohol abuse , depression , and anxiety ( ho et al . , 2014 ) .
another study reported that depression , alcohol use , and smoking were important predictors of internet addiction ( chang , chiu , lee , chen & miao , 2014 ) . given that smartphones are based on the internet , we assumed that smartphone addiction might share many social or psychological properties with internet addiction .
considering the findings described above , gender , alcohol use , smoking , anxiety , and depression were adopted as hypothesized risk variables in our study . as hypothesized protective factors , character strengths and resilience
the concept of character strength is often used in positive psychology and includes virtues such as wisdom and courage ( kim , yoon , kwon & ha , 2010 ) .
resilience refers to a person s ability to maintain psychological wellbeing and adapt successfully to acute stress , trauma , or more chronic forms of adversity ( jung et al . , 2012 ) .
resilience is a multidimensional construct that includes temperament , personality , and specific skills ( jung et al . , 2012 ) and is negatively associated with the pathophysiology of addictive disorders ( russo , murrough , han , charney & nestler , 2012 ) .
the aim of this study was to assess the risk and protective factors associated with smartphone addiction and to compare these factors with those linked to internet addiction .
a total of 463 college students from daejeon ( n = 155 ; 33.5% ) , sungnam ( n = 154 ; 33.3% ) , seoul ( n = 78 ; 16.9% ) , and nonsan ( n = 76 ; 16.4% ) participated in the study .
detailed research and instruction packages were sent to four colleges in each of these cities .
this package requested the allocation of 60 to 70 minutes of in - class testing time to complete the questionnaires .
of the 463 initial participants , 15 had more than 50% missing data and were therefore excluded .
the beginning of the first questionnaire contained items assessing the following demographic characteristics : age , academic year , smoking ( yes or no ) , and sex .
the smartphone addiction scale ( sas ; kwon et al . , 2013 ) was used to assess smartphone addiction .
the sas contains 33 items with a six - point response format ranging from strongly disagree
the sas covers the domains of daily - life disturbance , positive anticipation , withdrawal , cyberspace - oriented relationship , overuse , and tolerance .
internet addiction was assessed with young s internet addiction test ( iat ; young , 1998 ) , which has been widely used to screen for internet addiction .
the iat contains 20 items that are rated on a five - point scale ranging from very rarely
we used the korean version of the iat ( lee et al . , 2013 ) .
the alcohol use disorders identification test ( audit ; saunders , aasland , babor , de la fuente & grant , 1993 ) has been widely used to measure the alcohol use .
the audit is a 10-item questionnaire covering the domains of alcohol consumption , drinking behavior , and alcohol - related problems .
responses to each question are scored from zero to four , giving a maximum possible score of 40 . the korean version of the audit has confirmed reliability and validity ( lee , lee , lee , choi & namkoong , 2000 ) and was adapted in this study . in addition , we assessed the severity of depression and anxiety using the beck depression inventory ( bdi i ; beck , ward , mendelson , mock & erbaugh , 1961 ) and the state trait anxiety inventory , trait version ( stai t ; spielberger , 1983 ) , respectively .
i is composed of 21 items that inquire about the respondent s symptoms and changes in mood over the past week , with a four - point scale ( zero to three ) .
both scales have been translated into korean and have confirmed reliability and validity ( lim , lee & kim , 2005 ; rhee et al . , 1995 ) . to assess possible factors influencing smartphone addiction , we used
the character strengths test ( cst ; kwon , you , lim & kim , 2010 ) and the connor davidson resilience scale ( cd risc ; connor & davidson , 2003 ) . the korean version of the cst was developed with reference to the values in action inventory of strengths ( via is ; kim et al .
the cst is composed of 250 items that are rated on a four - point scale , ranging from strongly disagree ( zero ) to strongly agree ( three ) .
means for each of the cst s six virtues were calculated and used in the analyses described below .
risc contains 25 items using a five - point response format ranging from strongly disagree ( zero ) to strongly agree ( four ) .
the total score ranges from zero to 100 , with higher scores reflecting greater resilience .
risc , which has been found to be reliable and valid ( jung et al . , 2012 ) .
descriptive statistics were calculated for all variables ( i.e. , means and standard deviations for continuous variables and percentages for categorical variables ) .
stepwise multiple linear regressions were performed to determine the risk and protective factors for smartphone addiction and internet addiction .
all statistical analyses were performed using the statistical package for social sciences ( version 18.0 for windows ) .
the necessary ethical permissions were received from the institutional review board at eulji university hospital prior to the initiation of the research . before completing the questionnaires ,
a total of 463 college students from daejeon ( n = 155 ; 33.5% ) , sungnam ( n = 154 ; 33.3% ) , seoul ( n = 78 ; 16.9% ) , and nonsan ( n = 76 ; 16.4% ) participated in the study .
detailed research and instruction packages were sent to four colleges in each of these cities .
this package requested the allocation of 60 to 70 minutes of in - class testing time to complete the questionnaires .
of the 463 initial participants , 15 had more than 50% missing data and were therefore excluded .
the beginning of the first questionnaire contained items assessing the following demographic characteristics : age , academic year , smoking ( yes or no ) , and sex .
the smartphone addiction scale ( sas ; kwon et al . , 2013 ) was used to assess smartphone addiction .
the sas contains 33 items with a six - point response format ranging from strongly disagree
the sas covers the domains of daily - life disturbance , positive anticipation , withdrawal , cyberspace - oriented relationship , overuse , and tolerance .
internet addiction was assessed with young s internet addiction test ( iat ; young , 1998 ) , which has been widely used to screen for internet addiction .
the iat contains 20 items that are rated on a five - point scale ranging from very rarely
we used the korean version of the iat ( lee et al . , 2013 ) .
the alcohol use disorders identification test ( audit ; saunders , aasland , babor , de la fuente & grant , 1993 ) has been widely used to measure the alcohol use .
the audit is a 10-item questionnaire covering the domains of alcohol consumption , drinking behavior , and alcohol - related problems .
responses to each question are scored from zero to four , giving a maximum possible score of 40 .
the korean version of the audit has confirmed reliability and validity ( lee , lee , lee , choi & namkoong , 2000 ) and was adapted in this study . in addition , we assessed the severity of depression and anxiety using the beck depression inventory ( bdi i ; beck , ward , mendelson , mock & erbaugh , 1961 ) and the state trait anxiety inventory , trait version ( stai t ; spielberger , 1983 ) , respectively .
i is composed of 21 items that inquire about the respondent s symptoms and changes in mood over the past week , with a four - point scale ( zero to three ) . the stai
both scales have been translated into korean and have confirmed reliability and validity ( lim , lee & kim , 2005 ; rhee et al . , 1995 ) . to assess possible factors influencing smartphone addiction
, we used the character strengths test ( cst ; kwon , you , lim & kim , 2010 ) and the connor davidson resilience scale ( cd risc ; connor & davidson , 2003 ) . the korean version of the cst was developed with reference to the values in action inventory of strengths ( via is ; kim et al . , 2010 ; peterson & seligman , 2004 ) .
the cst is composed of 250 items that are rated on a four - point scale , ranging from strongly disagree ( zero ) to strongly agree ( three ) .
means for each of the cst s six virtues were calculated and used in the analyses described below . the cd
risc contains 25 items using a five - point response format ranging from strongly disagree ( zero ) to strongly agree ( four ) .
the total score ranges from zero to 100 , with higher scores reflecting greater resilience .
risc , which has been found to be reliable and valid ( jung et al . , 2012 ) .
descriptive statistics were calculated for all variables ( i.e. , means and standard deviations for continuous variables and percentages for categorical variables ) .
stepwise multiple linear regressions were performed to determine the risk and protective factors for smartphone addiction and internet addiction .
all statistical analyses were performed using the statistical package for social sciences ( version 18.0 for windows ) .
the necessary ethical permissions were received from the institutional review board at eulji university hospital prior to the initiation of the research . before completing the questionnaires ,
a total of 448 college students were included ( 39.7% male , n = 178 ; 60.3% female , n = 270 ) . the mean age of participants was 20.89 ( sd = 3.09 ) years .
the mean sas score was 68.46 ( sd = 24.95 ) , and the mean iat score was 34.14 ( sd = 11.23 ) .
sociodemographic and clinical characteristics of study participants notes : sas = smartphone addiction scale ; iat = young s internet addiction test ; audit = alcohol use disorders identification test ; bdi
risc = connor davidson resilience scale ; cst = character strengths test .
table 2 shows the pearson correlation coefficients of smartphone addiction and internet addiction with other variables .
pearson correlation coefficients of smartphone addiction and internet addiction with other variables notes : sas = smartphone addiction scale ; iat = young s internet addiction test ; audit = alcohol use disorders identification test ; bdi
trait anxiety inventory , trait version ; cd risc = connor davidson resilience scale ; cst = character strengths test . *
* * p < 0.01 . to identify the risk and protective factors for smartphone addiction and internet addiction ,
stepwise multiple linear regression analyses were performed . in the case of smartphone addiction , the independent risk factors were higher iat , audit , and stai
stepwise multiple regression analysis of smartphone addiction notes : dependent variable = smartphone addiction scale total score .
iat = young s internet addiction test ; audit = alcohol use disorders identification test ; bdi
t = state trait anxiety inventory , trait version ; cst = character strengths test .
t , and cst wisdom and knowledge scores , as well as male gender .
stepwise multiple regression analysis of internet addiction notes : dependent variable = young s internet addiction test total score .
t = state trait anxiety inventory , trait version ; cst = character strengths test .
in our study , higher levels of smartphone addiction were positively associated with female gender , internet addiction , anxiety , and alcohol use , while negative associations were found with depression and with character strength
higher levels of internet addiction were positively associated with male gender , smartphone addiction , anxiety , and character strength
we had originally hypothesized that smartphone addiction would share many social or psychological properties with internet addiction , but several findings were inconsistent with this assumption .
thus , we considered unique features of smartphones ( e.g. , availability for easy and frequent access ) in discussing our results below .
consistent with our assumption , our regression analyses revealed that increased internet addiction scores were associated with higher levels of smartphone addiction .
in addition , increased anxiety was associated with higher levels of both smartphone and internet addiction . as mentioned above , a number of previous studies showed that anxiety is a risk factor for internet addiction ( dalbudak , evren , aldemir & evren , 2014 ; floros , siomos , stogiannidou , giouzepas & garyfallos , 2014 ; ho et al . , 2014 ) .
according to another recent study , anxiousness is one of the behavioural addiction - prone personality traits ( davis & loxton , 2013 ) .
further , the possibility of interacting with smartphones easily and frequently may make these devices especially attractive for individuals with high anxiety . beyond these similarities ,
however , we also found a number of differences between the predictive factors for smartphone and internet addiction . in our regression analyses , increased smartphone addiction scores were associated with female gender , while increased internet addiction scores were associated with male gender . to explore these gender differences , we focused on the purposes of smartphone and internet use .
previous studies reported that males have a greater interest in games , cybersex , and gambling than do females ( cooper , morahan - martin , mathy & maheu , 2002 ; fattore et al . , 2014 ;
a study on internet addiction among south korean adolescents showed that except for academic purposes males tend to use the internet for online gaming and searching for information , while females tend to use the internet for chatting , sending messages , blogging , updating personal homepages , and searching for information ( heo et al . , 2014 ) .
on the other hand , regardless of gender , the primary purposes of smartphone use were chatting and using messenger systems , with making phone calls and searching for information as other major uses ( kim et al .
these results indicate that female internet users can engage in their favorite internet - based activities ( e.g. , chatting , using messenger systems , blogging ) more conveniently via smartphone because of these devices easy availability .
by contrast , male internet users do not typically use smartphones to engage in their favorite internet activities , such as online gaming , because the gaming capability of smartphones has traditionally been inferior to that of computers .
one study of smartphone use in south korea reported that women , but not men , were less likely to use their computers after obtaining a smartphone ( korea internet & security agency , 2013b ) .
this pattern of findings across studies may account for our finding that female gender was associated with higher levels of smartphone addiction .
we also found that increased alcohol use scores were associated with higher levels of smartphone addiction .
a study on the culture of drinking among south korean university students reported that the major purpose of drinking was facilitating social relationships ( chung , 2006 ) .
similarly , one of the major uses of smartphones is to facilitate interpersonal relationships . considering that the participants of our study were not alcohol - dependence patients , but college students
, it appears that increased alcohol use may be associated with smartphone addiction because of the role of smartphones in interpersonal relationships .
in addition , smartphones are readily accessible , which allows people to use their smartphones in pubs or bars .
were associated with lower levels of smartphone addiction in our study . by contrast , a recent study on smartphone addiction revealed that depression was significantly more prevalent in the risk - user group ( kim et al . , 2014 ) .
these diverging results may be partly attributable to the fact that our participants were college students rather than patients .
in addition , our study used the sas to assess smartphone addiction , and the cutoff score of the sas has not been determined yet ( kwon et al . , 2013 ) .
if we had divided the group based on risk , the results may have been different .
further , social withdrawal is a symptom of depression ( sue , sue & sue , 2010 ) , while smartphones are frequently used for the opposite process , social connection .
a previous study showed that impulsivity is a significant risk factor for smartphone addiction in university students ( kim et al . , 2014 ) . because temperance implies self - regulation ( kim et al . , 2010 )
we also think that smartphone addicts can easily satisfy their urge because smartphones are almost always available . regarding other character strengths ,
higher levels of internet addiction were positively associated with wisdom / knowledge and negatively associated with courage .
wisdom and knowledge encompass curiosity and a love of learning ( kim et al . , 2010 ) .
college students are unable to avoid using the internet to complete their research , reports , and homework .
moreover , internet - based learning and lectures have recently become very popular among south korean students .
in addition , evidence suggests that introverted personality characteristics and a passive coping style are risk factors for internet addiction ( xie , zhou , xu & peng , 2010 ; zamani , abedini & kheradmand , 2011 ) .
courage scores were associated with higher levels of internet addiction in our study , as courage encompasses vitality and bravery ( kim et al . , 2010 ) .
the patterns revealed in this study indicate the necessity of considering individuals purposes for smartphone and internet use when analyzing risk and protective factors for addiction .
furthermore , the features of smartphone devices , such as high availability , played a role in almost all findings .
these findings have important implications for future studies because as the purposes , contents , and functions of smartphones change , the risk and protective factors will change as well .
for example , if the gaming performance of smartphones is improved with technological advances , female gender may no longer be associated with higher levels of smartphone addiction .
thus , we believe it is necessary to place a greater emphasis on users purposes than on the devices themselves because the former represent the core of these addictions . for example , recent reports have framed internet gambling as an addiction to gambling , rather than as an addiction to the internet ( dastous & di gaspero , 2015 ; laplante , nelson & gray , 2014 ) . in the present study ,
smartphone addiction was similar to interpersonal relationship or not face - to - face communication addiction .
this is because the primary uses for smartphones are chatting , using messenger services , placing phone calls , blogging , and accessing social networking services ( kim et al . , 2014 ; korea internet & security agency , 2013a ) .
moreover , the differences between smartphone and internet addiction reflected the differences in purpose , contents , and functions between the two media .
from this perspective , smartphone addiction is a complex concept that includes various smartphone - accessible behavioral addictions such as gaming , chatting , shopping and gambling .
first , the participants were all college students , which may reduce the generalizability of the present results to other at - risk age groups .
for example , considering that excessive smartphone use is highly prevalent in teens ( korea internet & security agency , 2013a ) , it might have been appropriate to include teens in our sample .
second , the participants did not exhibit significant functional impairments , though we can not completely exclude the possibility of such impairments , as they were not specifically addressed in this study .
third , the questionnaire did not assess information such as hours of use , purpose of use , or contents most used . to obtain this information , we referred to other reports ( heo et al . , 2014 ; kim et al .
, 2014 ; korea internet & security agency , 2013a ) ; however , we believe that an investigation of this additional information is necessary to enhance clinical validity .
fourth , smartphones are based on the internet , and their functions are mostly operated via internet access
we believe that dividing the groups more clearly would be helpful in future studies ( e.g. , comparing internet use via smartphones with
lastly , there can be risk and protective factors beyond those measured in the present study , some of which may drive the overlap between the measured variables ( demirci , akgonul & akpinar , 2015 ; karadag et al . , 2015 ) .
until now , there have been few studies on smartphone addiction . as studies in this field progress , predictive factors for smartphone addiction will become more and more apparent .
the present findings will aid clinicians in distinguishing between predictive factors for smartphone and internet addiction and can consequently be utilized in the prevention and treatment of smartphone addiction .
moreover , the present report discusses the potential reasons underlying the differences between smartphone and internet addiction .
in addition , the present study suggests the possibility that smartphone use is not an objective in and of itself but instead is a means of engaging in addictive activities that are accessible on these devices .
hja , swc , ejc and wys conducted the data collection from the participants in colleges .
swc and hcy conducted the statistical analysis and wrote the first draft of the manuscript .
all authors contributed to development of the manuscript , revised it critically and have approved the final manuscript .
| background and aimssmartphone addiction is a recent concern that has resulted from the dramatic increase in worldwide smartphone use .
this study assessed the risk and protective factors associated with smartphone addiction in college students and compared these factors to those linked to internet addiction.methodscollege students ( n = 448 ) in south korea completed the smartphone addiction scale , the young s internet addiction test , the alcohol use disorders identification test , the beck depression inventory i , the state trait anxiety inventory ( trait version ) , the character strengths test , and the connor davidson resilience scale .
the data were analyzed using multiple linear regression analyses.resultsthe risk factors for smartphone addiction were female gender , internet use , alcohol use , and anxiety , while the protective factors were depression and temperance .
in contrast , the risk factors for internet addiction were male gender , smartphone use , anxiety , and wisdom / knowledge , while the protective factor was courage.discussionthese differences may result from unique features of smartphones , such as high availability and primary use as a tool for interpersonal relationships.conclusionsour findings will aid clinicians in distinguishing between predictive factors for smartphone and internet addiction and can consequently be utilized in the prevention and treatment of smartphone addiction . |
angiopoietins are a family of growth factors which act on the tie receptor on endothelial cells .
the angiopoietin family consists of 4 angiopoietins , i.e. , angiopoietin-1 ( ang1 ) , angiopoietin-2 ( ang2 ) , angiopoietin-3 ( ang3 ) , and angiopoietin-4 ( ang4)1 - 3 ) .
ang1 is known as an angiogenic factor4 ) , however , the function of ang2 , ang3 and ang4 is not well known .
it has been also reported that tie2 is also expressed in macrophages , eosinophils , and hematopoietic stem cells5 , 6 ) .
although tie1 and tie2 share a similar structure consisting of an extracellular domain with 33% similarity and an intracellular tyrosine kinase domain with 76% similarity , the exact role of tie1 is not well known 7 ) .
ang1 is a widely expressed ligand for the tie2 tyrosine kinase receptor that is expressed on endothelial cells , and it regulates vascular growth , development , maturation , and permeability8 , 9 ) .
ang1-induced tie2 phosphorylation in endothelial cells can activate the protein kinase b / akt pathway that conducts endothelial survival10 - 12 ) .
although ang1 is known as an angiogenic factor , it has been also demonstrated that ang1 has an anti - inflammatory effect13 , 14 ) .
although the exact role of ang2 is not well known , it has been reported that ang2 functions as an antagonist ligand of tie215 ) . ang1 has potential therapeutic applications in inducing angiogenesis , enhancing endothelial cells survival , and preventing vascular leakage12 , 16 - 20 ) ( fig .
ang1 is also associated with physiologic or pathophysiologic conditions in the kidney21 ) . in kidney development
, tie2 is detected in capillaries of the nephrogenic cortex , glomerular tufts , cortical interstitium , and medulla including vessels in the vasa recta22 , 23 ) .
thus , ang1 and tie2 play roles in the maturation of glomeruli and the vasa rectae .
ang1 protein is detected in podocytes in normal glomeruli and was highly expressed in podocyte foot processes24 ) .
tie2 has been demonstrated on glomerular capillary endothelial cells and peritubular capillary endothelial cells23 ) .
thus , circulating ang1 may have an effect on renal tie2 in the endothelial cell and renal ang1 may also have paracrine effect on renal tie225 , 26 ) .
disturbance of endothelial integrity in the kidney may cause a reduction in glomerular filtration rate or proteinuria .
ang1 in the glomerulus or renal epithelial cells may have a role in maintenance of the glomerular or peritubular endothelium in the kidney .
in pathophysiologic conditions , folic acid - induced nephropathy is associated with increased ang1 protein expression in renal epithelia and arteries27 ) .
it was also reported that loss of glomerular capillaries during the course of anti - glomerular basement membrane glomerulonephritis in mice was temporally associated with decreases in endothelial survival molecules ang128 ) .
therefore , ang1 may have an important role in maintenance of normal kidney development of the glomerular or peritubular endothelium and various kidney disease conditions .
the severity of tubulointerstitial changes is the best indicator of the progression of renal dysfunction29 , 30 ) .
renal tubulointerstitial fibrosis is an important feature in unilateral ureteral obstruction ( uuo ) . in humans ,
chronic and acute ureteral obstruction can occur in various clinical situations such as ureteral stone or ureteral carcinoma .
injury to the renal microvasculature and inflammatory condition may be major factors in the process of kidney disease31 ) .
in particular , injury to the peritubular capillary endothelium of the kidney may be a factor in tubulointerstitial disease32 - 34 ) .
it has been reported that impaired angiogenesis may occur in the diseased kidney and can contribute to renal scarring33 ) .
renal ischemia that is caused by vascular obliteration can be a major contributor to renal scarring .
therefore , endothelial cells play an important role in renal disease progression in the unilateral ureteral obstructed kidney .
because renal microvasculature injury involves a critical process in renal fibrosis , a growth factor or cytokine with an endothelial protective or angiogenic effect may have a protective role in renal fibrosis in the uuo model35 - 37 ) .
recently , a variant of ang1 , cartilage oligomeric matrix protein ( comp)-ang1 was recently developed .
comp - ang1 is soluble and more potent than native ang1 in phosphorylating tie2 and signaling via akt in primary cultured endothelial cells13 , 38 ) .
thus , i evaluated the protective effect of comp - ang1 in the uuo - induced renal fibrosis model39 ) . in the uuo model ,
comp - ang1 preserved the renal platelet - endothelial cell adhesion molecule-1- and tie2-positive endothelial cell .
morphologic examination demonstrated less tubular injury and renal interstitial fibrosis in mice that received comp - ang1 than in vehicle - treated mice .
renal surface microvasculature and renal blood flow were higher after treatment with comp - ang1 than in vehicle - treated mice .
comp - ang1 treatment suppressed monocyte / macrophage infiltration , tissue levels of transforming growth factor 1 ( tgf-1 ) , and smad 2/3 phosphorylation and increased smad 7 in the obstructed kidney .
these results suggest that comp - ang1 treatment can prevent the progression of renal fibrosis in uuo .
inflammatory processes have been recently seen as the important factor in the pathogenesis of diabetic nephropathy . in this study , db /
db mice were treated with adenovirus expressing either comp - ang1 or lacz40 ) . to evaluate histology , inflammatory , metabolic , and fibrotic parameters and signalling pathways , we used diabetic nephropathy model .
comp - ang1 reduced albuminuria in 24 hour urine analysis and decreased mesangial expansion , thickening of the glomerular basement membrane , and podocyte foot process broadening and effacement in histologic examination .
comp - ang1 decreased both kidney expression of the adhesion molecule and the number of f4/80-positive macrophage infiltration in diabetic db / db mice .
in addition , comp - ang1 significantly decreased fasting blood glucose level , epididymal fat weight to body weight ratio , and epididymal adipocyte size in diabetic db / db mice .
comp - ang1 also ameliorated the fibrotic process in the kidney of diabetic db / db mice through its anti - inflammatory and metabolic effects .
comp - ang1 suppressed renal levels of tgf-1 , -smooth muscle actin , fibronectin , as well as smad 2/3 , but increased smad 7 . in human umbilical vein endothelial cells , comp - ang1 treatment decreased high glucose - induced nuclear factor-b ( nf-b ) activation .
comp - ang1 mediated inhibition of increased nf-b - dna binding activity in nuclear extracts from human umbilical vein endothelial cells grown in high glucose was significantly blocked by soluble tie2 receptor - fc .
however , there are several conditions associated with comp - ang1 such as slight increased redness in the nose and increased vascular density in the trachea .
these results suggest that comp - ang1 ameliorated the fibrotic processes in the kidney of diabetic db / db mice through its anti - inflammatory or metabolic effects .
in cyclosporine ( csa)-induced renal injury , comp - ang1 significantly decreased csa - induced tubular damage and tubulointerstitial fibrosis in histologic examination .
comp - ang1 also reduced the number of macrophage infiltration and expression of adhesion molecules in the csa - induced renal injury model .
comp - ang1 administration decreased csa - induced increase of tgf-1 and smad 2/3 in kidneys , while increasing smad 7 levels .
laser - doppler sonographic findings and endothelial factor viii staining revealed that comp - ang1 had a protective effect on peritubular vasculature and intrarenal hemodynamic alteration in csa - induced renal injury .
the protective effect of comp - ang1 on of the renal endothelial cell and regulation of inflammatory process may be an important therapeutic target of renal disease .
therefore , comp - ang1 may be an endothelium - specific therapeutic modality in various renal diseases . | injury to the renal microvasculature and inflammatory process may be major factors in the progression of renal disease , therefore , protection of the renal endothelial cell and regulation of inflammatory process may be an important therapeutic target of renal disease .
thus , we evaluated the protective effect of cartilage oligomeric matrix protein - angiopoietin-1 ( comp - ang1 ) in unilateral ureteral obstruction ( uuo)-induced renal fibrosis , cyclosporine a ( csa)-induced renal injury , and the diabetic nephropathy model . in the uuo model ,
morphologic examination indicated less tubular injury and tubulointerstitial fibrosis in mice that received comp - ang1 compared to vehicle - treated mice .
interstitial type i collagen , myofibroblast accumulation , renal surface microvasculature and renal blood flow were higher after treatment with comp - ang1 compared to vehicle - treated mice .
comp - ang1 treatment decreased monocyte / macrophage infiltration , tissue levels of transforming growth factor 1 , and smad 2/3 phosphorylation and increased smad 7 in the obstructed kidney . in csa - induced renal injury ,
histologic examination showed significantly decreased csa - induced tubular damage and tubulointerstitial fibrosis in comp - ang1 treated mice .
comp - ang1 administration also decreased increased macrophage infiltration , adhesion molecule expression , tgf-1 , and smad 2/3 levels in csa - treated kidneys , while increasing smad 7 levels .
laser - doppler sonographic findings and endothelial factor viii staining revealed that comp - ang1 had a preservative effect on peritubular vasculature . in the diabetic nephropathy model , comp - ang1 reduced albuminuria and decreased mesangial expansion , thickening of the glomerular basement membrane and podocyte foot process broadening and effacement .
comp - ang1 may delay the fibrotic changes in the kidney of diabetic db / db mice through its anti - inflammatory or metabolic effects . in conclusion
, comp - ang1 may be an endothelium - specific and anti - inflammatory therapeutic modality in fibrotic renal disease . |
predominantly found in the tendon sheaths or joints of the fingers and toes , and rarely in larger joints such as the knee or ankle.12 although localized nodular synovitis involving the infrapatellar fat pad has been occasionally reported,34 mechanical symptoms such as locking or restricted knee motion are rare , with vague anterior knee pain being the most common symptom.5 localized nodular synovitis of the knee is usually easily identified using arthroscopy and can usually be removed arthroscopically via conventional anterior portals.6 the present report describes a case of localized nodular synovitis arising from the infrapatellar fat pad .
the lesion caused extension limitation due to impingement by the mass along the patellofemoral joint .
arthroscopy required a superior - superior triangulation approach to identify and remove the mass because the mass and a thickened infrapatellar plica obstructed the anterior portal .
a 24-year - old male presented with a 2-year history of pain in the left knee joint on terminal extension and extension limitation .
the symptoms developed insidiously without any antecedent trauma . he reported discomfort when ascending stairs , and no pain at rest or in bed at night , nor any constitutional symptoms .
an initial clinical examination revealed mild effusion but no clicking or localized joint line tenderness .
tests for lachman 's sign , anterior drawer , pivot shift , and posterior drawer were all negative , indicating there was no knee instability .
the knee joint was able to reach full flexion , but extension was restricted by 20. attempts to reach full extension resulted in severe anterior knee pain .
sequential magnetic resonance image ( mri ) scans were performed , and t1-weighted images revealed an oval shaped well - defined mass of intermediate signal intensity that lay superior to the infrapatellar fat pad and in between the distal half of the retropatellar region and the distal femur trochlea [ figure 1a ] .
t2-weighted images showed that the mass was inhomogeneous and had relatively high signal intensity with hypointense areas .
the mass was connected to a fibrotic thickening of the infrapatellar plica which traversed the fat pad [ figure 1b ] .
( a ) t1 weighted image showing the well - defined oval - shaped mass with intermediate signal intensity located superior to the infrapatellar fat pad and between the distal half of the retropatellar region and the distal femur trochlea . ( b )
t2 weighted image showing that the mass appears as inhomogeneous , and with relatively hyperintense signal intensity with hypointense areas .
note the fibrotic thickening of the infrapatellar plica ( white arrows ) which traverses the fat pad and connects to the mass an arthroscopic examination and excision biopsy were performed .
however , we found it very difficult to insert the arthroscope into the joint via those portals due thick soft tissue .
we suspected that an extensively hypertrophied infrapatellar plica had adhered to the mass . to overcome the problems associated with those obstructions
the superolateral portal view revealed a well - encapsulated , round pan - shape nodular brownish mass that extended upward and entered the patellofemoral joint upon joint extension so as to prevent full extension . that mass retracted when the joint was flexed greater than 30 [ figure 2a and b ] .
those arthroscopic findings were consistent with the severe pain experienced on terminal extension and the extension limitation of the joint .
we observed no damage to the cruciate ligament or menisci , nor did we observe articular cartilage without villous fronds . to remove the mass
, we placed the knee at maximum extension such that the mass entered the patellofemoral joint , and then excised it using superior triangulation ( i.e. , a superolateral viewing portal and a superomedial working portal , or vice versa ) .
after excision , we assessed whether the knee could be moved through a full range of movement , and simultaneously confirmed via arthroscopy that there was no longer any mass impingement into the joint or any joint locking signs .
arthroscopic view showing the round , pan - shape nodular brownish mass impinged in between the patellofemoral joint at full extension ( a ) which then retracted when the knee was flexed at greater than 30 ( b ) peroperative photograph showing the gross appearance of the resected mass , with yellowish and fibrous cut surfaces histopathological examination of the mass revealed that it was composed of an admixture of osteoclast - type giant cells and mononuclear cells in a collagenous stroma .
nuclear pleomorphisms and mitotic figures were rare , and there were no villous projections of the synovium , either macroscopically or microscopically [ figure 4 ] .
there were no postoperative complications , and the patient was discharged on postoperative day 2 . at a 22-month followup , the patient was found to be pain - free and had a full range of knee motion with no evidence of recurrence .
the patient was informed that data concerning the case would be submitted for publication , and he consented .
note the admixture of osteoclast - type giant cells and mononuclear cells in a collagenous stroma .
the present report describes the diagnosis and treatment of localized nodular synovitis in the infrapatellar fat pad which caused extension limitation and knee joint pain .
the extension limitation appeared to be due to an infrapatellar fat pad mass being caught in the patellofemoral joint .
the mass was identified and excised arthroscopically using superior - superior triangulation because access via standard anteromedial and anterolateral portals was obstructed by adhesions and hypertrophied soft tissue around the mass .
localized nodular synovitis has often been identified as a giant cell tumor of the tendon sheath ( gctts ) since the two conditions share similar pathology .
although some vagueness remains regarding the features that distinguish those two conditions , a review of the literature indicates that gctts is considered as an isolated discrete lesion found predominantly in the tendon sheaths or joints of the fingers and toes , whereas localized nodular synovitis is considered as a solitary intra - articular nodule arising from an area of abnormal synovium of a large joint such as the knee.78 those two disease entities differ from diffuse - type pigmented villonodular synovitis ( pvns ) which shows more aggressive pathology findings ( i.e. diffuse frond - like projections of the synovium and abundant hemosiderin deposition3 ) and requires a complete synovectomy as well as mass excision as it has a higher recurrence rate compared to localized nodular synovitis or gctts .
a retrospective review of 26 cases of localized nodular synovitis of the knee by dines et al.5 demonstrated that vague pain was the most common presentation complaint ( 92% of patients ) , whereas mechanical symptoms such as locking or restricted knee motion were rare .
mechanical symptoms were found to occur more commonly in cases involving localized nodular synovitis of a large size that was sandwiched into a small space between joint structures such as the infrapatellar fat pad.4 however , although the infrapatellar fat pad is a common site for localized nodular synovitis,3 a large localized nodular synovitis in the fat pad does not always result in mechanical symptoms because the fat pad can tolerate significant volume changes such as those which occur during knee motion.9 if a meniscal tear can be completely excluded , the intra - articular cause of knee extension limitation associated with anterior knee pain or swelling usually originates from lesions of the infrapatellar fat pad area .
possible differential diagnoses of our patient included a benign mass , such as an intraarticular [ osteo ] chondroma , localized nodular synovitis , or fibroma of the tendon sheath ; a malignant mass such as a synovial sarcoma ; or hoffa 's disease.1011 our patient showed extension limitation and pain on full extension .
an mri showed localized nodular synovitis located in the superior infrapatellar fat pad , and between the distal half of the retropatellar region and the trochlea of the distal femur .
we believe that this site could be quite narrow at knee extension , and this may cause a bottleneck phenomenon since the contact area of the patellofemoral joint moves distally as extension increases.12 although patients with localized nodular synovitis have a better prognosis than patients with diffuse - type pvns , due to a much lower recurrence rate , the recurrence rate of localized nodular synovitis is still 10 - 20%.13 the major predictor of recurrence is the completeness of surgical excision.1 other potential risk factors include cell type , mitotic activity and radiological osseous erosion.14 recently , arthroscopic excision has been preferred to arthrotomy unless the mass is exceptionally big or is located in areas difficult to access arthroscopically.15 others report arthroscopic excision of localized nodular synovitis around the infrapatellar fat pad via a conventional anterior portal.1617 however , in our case , it was difficult to insert the arthroscopic camera through the anterolateral portal and locate the mass due to obstruction by a thickened edematous infrapatellar plica and an hypertrophied fat pad which adhered to the mass .
although an arthroscopic approach through multiple portals can be utilized for complete excision , this approach is associated with a significant risk of inadequate excision and subsequent recurrence , particularly for lesions in the posterior compartment of the knee .
therefore , open excision is more advisable for recurrent lesions.18 in conclusion , the present report shows that limitation of knee extension can be caused by the displacement into the patellofemoral joint of a localized nodular synovitis on the infrapatellar fat pad .
in addition , we found that superior - superior triangulation can be a valuable approach for locating and excising an infrapatellar fat pad mass that is difficult to identify and excise via a conventional anterior portal due to an obstructed visual field . | we report a case of localized nodular synovitis of the infrapatellar fat pad impinging on the patellofemoral joint causing limitation of extension .
arthroscopy involved use of a superolateral portal because location of lesion hindered access via a conventional anterior portal .
the infrapatellar mass impinged in the patellofemoral joint upon knee extension and retracted upon flexion .
superior - superior triangulation allowed for complete excision of the mass . |
salmonellosis due to nontyphoidal salmonella ( nts ) infection is a global public health concern , particularly in salmonella endemic low and middle income countries ( lmics ) .
treatment is critical for persons with severe disease , particularly children and immune compromised people .
treatment with an appropriate antibiotic can shorten the duration of symptoms , significantly reduce severity of disease and the risk of transmission , and prevent potentially lethal complications .
emergence of resistance to first - line therapy like ampicillin , chloramphenicol , and cotrimoxazole including ciprofloxacin among salmonella spp . during the last decades
has complicated the situation [ 1 , 2 ] . for treatment of salmonella infection resistant to these drugs , extended - spectrum cephalosporins ( escs )
are considered as an alternative therapeutic choice . with the increased use of -lactam antibiotics to treat enteric infection , salmonella spp .
had acquired resistant to third generation cephalosporin antibiotics in different parts of the world and had been associated with clinical treatment failure [ 3 , 4 ] .
extended - spectrum beta - lactamases ( esbl ) are usually encoded by large plasmids ( 100 kb ) that are transferable from strain to strain and between bacterial species [ 57 ] .
resistance to escs is mediated primarily by production of class a esbls , which can hydrolyze oxyimino cephalosporins but are not active against cephamycins and carbapenems .
the plasmid - encoded ctx - m type esbls production was initially identified in 1983 in germany .
the ctx - m family enzymes , which confer high levels of resistance to escs , have similar substrate specificities and inhibitor profiles to tem .
the ctx - m type esbls have been reported to be found worldwide in different members of enterobacteriaceae isolated from human and other animal sources .
earlier we have reported the emergence of blactx - m and blatem type esbl producer s. typhi in one - year - old child with recurrent high - grade fever . in recent years
there have been several reports indicating the emergence of resistance to -lactam antibiotics among salmonella species . here , we present blatem gene mediated esbl production among salmonella spp
. isolated from stool specimen of patients with diarrhea in an urban setting of bangladesh .
as part of a microbiological analysis of stool sample received at dhaka treatment centre of international centre for diarrheal diseases research , bangladesh ( icddr , b ) during 20052013 , we have analyzed 128,312 fecal specimen following standard microbiological method to identify salmonella spp .
the putative extended - spectrum beta - lactamase ( esbl ) producing strains were tested by the double - disc synergy method and detection of -lactamase genes ( blactx - m , blatem , blashv , and blaoxa genes ) was performed by pcr as describe elsewhere .
overall , the annual incidence of salmonella infection showed a decreasing trend and the proportion came down significantly from 2% in 2005 to 1.0% in 2013 ( p < 0.001 ) .
( 2120 , [ 1.7% ] ) , nontyphoidal salmonella ( nts ) isolates were more frequently isolated than typhoidal salmonella ( ts ) ( 72.8% versus 27.2% , p < 0.001 ) .
demographic information showed that salmonellae were isolated from patients of all age groups with a maiden age of 4.04 years .
of the total salmonella positive patients , 51.2% ( n = 1086 ) were children aged less than five years . among the ts serogroups ,
s. typhi was predominant ( 404 , [ 65.1% ] ) followed by s. paratyphi b ( 139 , [ 22.4% ] ) and s. paratyphi a ( 78 , [ 12.6% ] ) .
of the nts isolates , serogroups c1 strains were more frequently isolated ( 560 , [ 37.4% ] ) , followed by b ( 203 , [ 13.5% ] ) , c2 ( 203 , [ 13.5% ] ) , e ( 127 , [ 8.5% ] ) , d ( 94 , [ 6.3% ] ) , g ( 79 , [ 5.3% ] ) , nontypeable salmonella ( 54 , [ 3.6% ] ) , s. typhimurium ( 2 , [ 0.1% ] ) , and a ( 1 , [ 0.06% ] ) serogroup .
the yearly distribution of salmonella spp . showed distinct seasonality with higher isolation during may to october in each year .
temporal shift was noted in the prevalence of serogroups , seasonality , gender distribution , and resistance pattern between ts and nts isolates .
around 40% of the salmonella isolates showed resistance to nalidixic acid ( na ) followed by 36% to ampicillin ( amp ) , 20% to cotrimoxazole ( sxt ) , 4% to ciprofloxacin ( cip ) , 13% to chloramphenicol ( c ) , and 4% to ceftriaxone ( cro ) .
resistance to 3 antibiotic classes was more common among ts strains than nts counterpart ( 36.6% versus 19.8% , p < 0.001 ) . among the representative salmonella
isolates with unusual resistant phenotype ( ampccipcronasxt ) , first identified in 2011 , blatem gene was detected in 88% ( 7/8 ) of the strains ( figure 1 ) .
interestingly , one s. typhi was positive for both blatem and blactx - m genes which is a very rare phenomenon . in our earlier report , we noticed that this same phenomenon was observed in one s. typhi isolated from blood of a typhoid patient .
these findings suggest that multi - esbl producer strains are circulating in bangladesh . however , to the best of our knowledge , this is the first report of esbl production among salmonella isolated from stool specimen of diarrheal patients in urban dhaka , bangladesh .
detailed molecular characterization including sequencing is necessary for further geno- and subtyping of these strains .
the study finding reflects the higher prevalence of mar salmonella spp . among children aged < 5 years and
blatem gene mediated esbl production among salmonella spp . isolated from stool sample of diarrheal patient in urban bangladesh .
therefore , it is important to establish a surveillance program to understand actual disease burden due to salmonella as well as promote specific and actual line of therapy for salmonellosis . | salmonellosis , an acute invasive enteric infection , is endemic in bangladesh .
we analyzed 128,312 stool samples of diarrheal patients to identify salmonella spp . during 20052013 .
a total of 2120 ( 1.7% ) salmonella spp . were isolated and the prevalence of salmonella spp .
decreased significantly over time ( 21% , p < 0.001 ) . among the typhoidal salmonella ( ts )
serogroups , s. typhi was predominant ( 404 , [ 65.1% ] ) followed by s. paratyphi b ( 139 , [ 22.4% ] ) and s. paratyphi a ( 78 , [ 12.6% ] ) . of the nontyphoidal salmonella ( nts )
isolates , the serogroup c1 ( 560 , [ 37% ] ) was predominant followed by b ( 379 , [ 25% ] ) , c2 ( 203 , [ 14% ] ) , e ( 127 , [ 9% ] ) , and d ( 94 , [ 6% ] ) .
most of the resistance was found towards nalidixic acid ( 40% ) , ampicillin ( 36% ) , cotrimoxazole ( 20% ) , chloramphenicol ( 13% ) , ciprofloxacin ( 4% ) , and ceftriaxone ( 4% ) .
interestingly , 32% of the isolates showed reduced susceptibility to cip .
multiantibiotic resistance ( mar , 3 drugs ) was more common among ts than nts strains ( p < 0.001 ) . among the representative
ceftriaxone - resistant isolates , blatem gene was detected among 88% ( 7/8 ) of the strains , whereas only one strain of s. typhi was positive for both blatem and blactx - m genes .
the study reflects higher prevalence of mar salmonella spp . and
is the first to report the blatem gene mediated esbl production among salmonellae in bangladesh .
emergence of mar salmonella spp .
in particular esbl strains should be considered a public health concern . |
ubiquitous computing , following the vision of weiser , aims to embed small computer devices into every day objects augmenting them with new functionality , building an environment full of distributed computers .
scenarios for major applications include homecare monitoring [ 4 - 6 ] and assistance for health professionals [ 7 - 9 ] . in the ubiquitous healthcare environment ,
health data are transferred to a remote healthcare server by a wearable system or mobile computer .
collected health data can then be managed and analyzed in the server computer to generate case - specific advice .
despite the fact that ubiquitous healthcare computing generates massive amounts of data , healthcare enterprises are knowledge poor because this data is rarely transformed into strategic decision - support resources .
an intelligent active knowledge system for health data management is necessary to support clinical decisions by health professionals .
dual model architecture is gaining relevance for the development of an electronic health records system for ubiquitous healthcare .
this architecture , which takes into account the dynamic nature of the healthcare environment , is based on two modeling levels : information and knowledge .
the information level is provided by the reference model and the knowledge level by the archetype model .
the first is the separation of concepts into two levels , one defining the reference model and another , formed by formal models of domain concepts , defining different clinical concepts .
the second rule is that computing systems are based on the reference model , and valid healthcare records extracts are instances of the reference model .
this methodology is currently used by the major standards for representing electronic health records - openehr , cen , and health level seven ( hl7 ) .
based on dual model architecture , two major technological approaches for semantic interoperability are the ontology - based and the archetype models . the ontology - based modelof clinical information is designed to make health information systems properly interoperable and safely computable .
the openehr archetype model is an open standard specification that describes the management , storage , retrieval , and exchange of health data from electronic health records .
we review here these two technological approaches for semantically interoperable electronic health records to construct an intelligent active knowledge system for ubiquitous healthcare data management .
over the past decades , ontologies have become key components of information systems and have found various applications includingnatural language processing , software engineering , and knowledge management in the semantic web and healthcare .
ontology engineering and management in healthcare have a long tradition , starting with controlled vocabularies with restricted lists of terms such as catalogs , unstructured glossaries , and structured arrangements of words . nowadays
weed 's " problem - oriented medical record ( pomr ) " methodology formally linked a model of process of care to the information gathered during that care .
einstein 's " hypothetico - deductive " model of clinical reasoning mainly accounted for the cognitive aspects of clinical care during diagnosis .
the danish " general electronic patient journal ( g - epj ) " included a conceptual model of the iterative problem - solving process and categories of information , implementing both process and information based on rational problem - solving , but proved too rigid in clinical practice .
various clinical modeling efforts from the riche project to the present hl7 version 3 standard have based their models on an " act management " paradigm , in which all aspects of healthcare are represented as " acts " , enabling " everything that is done " to be recorded . currently , the most widely - used ontology editor is protg .
protg is an open source ontology development and knowledge acquisition environment developed by stanford medical informatics . as a java tool
, it provides an extensible architecture for the creation of customized knowledge - based tools and assists users in the construction of large electronic knowledge bases .
protg provides two main ways of modeling ontologies : 1 ) protg - frames editor and 2 ) protg - owl editor . in protg - frames ,
the knowledge model is compatible with the open knowledge base connectivity protocol ( okbc ) .
protg supports the construction of domain ontology , the design of knowledge - acquisition forms , and entering domain knowledge .
it provides a platform which can be extended with graphical widgets for tables , diagrams , and animation components to access other knowledge - based system embedded applications .
while they offer a stable , language - independent vocabulary that helps standardize and explain the meaning of domain terms , the use of ontology editors such as protg is complex and therefore less suited for application to clinical practice .
weed 's " problem - oriented medical record ( pomr ) " methodology formally linked a model of process of care to the information gathered during that care .
einstein 's " hypothetico - deductive " model of clinical reasoning mainly accounted for the cognitive aspects of clinical care during diagnosis .
the danish " general electronic patient journal ( g - epj ) " included a conceptual model of the iterative problem - solving process and categories of information , implementing both process and information based on rational problem - solving , but proved too rigid in clinical practice .
various clinical modeling efforts from the riche project to the present hl7 version 3 standard have based their models on an " act management " paradigm , in which all aspects of healthcare are represented as " acts " , enabling " everything that is done " to be recorded .
protg is an open source ontology development and knowledge acquisition environment developed by stanford medical informatics . as a java tool
, it provides an extensible architecture for the creation of customized knowledge - based tools and assists users in the construction of large electronic knowledge bases .
protg provides two main ways of modeling ontologies : 1 ) protg - frames editor and 2 ) protg - owl editor . in protg - frames ,
the knowledge model is compatible with the open knowledge base connectivity protocol ( okbc ) .
protg supports the construction of domain ontology , the design of knowledge - acquisition forms , and entering domain knowledge .
it provides a platform which can be extended with graphical widgets for tables , diagrams , and animation components to access other knowledge - based system embedded applications .
while they offer a stable , language - independent vocabulary that helps standardize and explain the meaning of domain terms , the use of ontology editors such as protg is complex and therefore less suited for application to clinical practice .
openehr archetype models , commonly referred to as archetypes are clinical data models that conform to the openehr reference model .
the openehr foundation , an international , on - line community whose aim is to promote and facilitate progress towards electronic healthcare records of high quality , to support the needs of patients and clinicians anywhere , is the originator .
the openehr 's information model is the archetype , a re - usable formal model of a domain concept .
information models are templates for the acquisition of clinical data which provide semantic interoperability within the bounds of the given information model but not between different information models .
archetypes are usually built by domain experts and are computable expressions of a domain content model of medical records , defining the particular configuration or desired composition of instances of clinical concepts .
expression is in the form of structured constraint statements , inherited from the reference model .
this model describes the health record itself , and is composed of packages , defining openehr specification documents , and information models . the ehr information model is organized in folders and compositions ( figure 1 ) .
the package is the top level structure of the ehr and contains the entry and navigation packages . in general ,
archetypes are defined for wide use ; however , they can be specialized to include local particularities and in healthcare , an archetype can model concepts .
an archetype is divided into 3 main parts : descriptive = a unique identifier , machine - readable code describing the clinical concepts modeled by the archetype and various metadata , definition = the main part describing the architecture , content , or restrictions of the archetype , andontology = defines the vocabulary and may contain language translations of code and meanings of codes used within the archetypes and tied to external vocabularies such as snomed or loinc .
descriptive = a unique identifier , machine - readable code describing the clinical concepts modeled by the archetype and various metadata , definition = the main part describing the architecture , content , or restrictions of the archetype , and ontology = defines the vocabulary and may contain language translations of code and meanings of codes used within the archetypes and tied to external vocabularies such as snomed or loinc .
this structure constrains the cardinality and content of information model instances complying with the archetype .
codes representing the meanings of nodes and constraints on text or terms binding to terminologies such as snomed or loinc are stated in the ontology section .
the formal language for expressing archetype is archetype definition language ( adl ) , a knowledge description language .
adl uses three other syntaxes to describe constraints on data which are instances of some information model - cadl ( constraint from adl ) , dadl ( data definition from adl ) , and a version of first - order predicate logic ( fopl ) .
archetypes are represented in web ontology language ( owl ) by mapping each adl construct to its owl counterpart .
the intended purpose of archetypes is to empower clinicians to define the content , semantics , and data - entry interfaces of systems independently from the information systems .
a feature of archetypes is the ability to separate internal model data from formal terminologies .
the internal data are assigned local names which can later be bound or mapped to external terminology codes .
this feature eliminatesthe need to make changes to the model whenever the terminology changes . in archetype models ,
snomed - ct aims to be a comprehensive terminology that provides clinical content and expressivity for clinical documentation and reporting .
snomed has been developed using the description logic ontylog to allow formal representation of the meanings of concepts and their inter - relationship .
the snomed hierarchy is easy to compute , which was the primary reason for selecting the terminology for the research .
snomed - ct has approximately 370,000 concepts and 1.5 million triples i.e. relationships of one concept with another in the terminology ( figure 2 ) .
besides medical records , various medical data measured from sensors and devices must be interchangeable in ubiquitous healthcare .
the most common data exchange standards used in healthcare it are hl7 for general health information , digital imaging and communications in medicine ( dicom ) for medical images , and iso / ieee 11073 for medical devices .
hl7 version 3 has evolved from a pure data interchangeable format to include a reference information model and a suite of other standards for capturing the conceptual structure of health information systems .
both hl7 and dicom are built on the " free open source " philosophy therefore , most of the enabling and editing tools are " free open source " software as well .
a list of the major " free open source " tools available for data interchange implementation is shown in table 1 .
although not stated in the above sections , national and international standards developments , connectivity using hl7 , and document exchange using hl7 cda are also contributing to the implementation of content - based ubiquitous healthcare systems .
in the health informatics community , a considerable amount of progress has been made in the area of for semantic interoperable electronic health records for ubiquitous use of patient information and health knowledge management .
these methodological developments , particularly the ontological approach and openehr archetype , have changed ubiquitous healthcare allowing it to become more semantically interoperable and individual patient - based , these advances will allow healthcare professionals to manage complete electronic healthcare records of the patients regardless of which institution generates each clinical session . | in order to provide more effective and personalized healthcare services to patients and healthcare professionals , intelligent active knowledge management and reasoning systems with semantic interoperability are needed .
technological developments have changed ubiquitous healthcare making it more semantically interoperable and individual patient - based ; however , there are also limitations to these methodologies . based upon an extensive review of international literature ,
this paper describes two technological approaches to semantically interoperable electronic health records for ubiquitous healthcare data management : the ontology - based model and the information , or openehr archetype model , and the link to standard terminologies such as snomed - ct . |
the protein predictions from monosiga brevicollis ( n = 9196 , genome assembly version 1.0 ; king et al .
i ( n = 32,415 , genome assembly version 1.0 , unpublished data ) , helobdella robusta ( n = 23,432 , genome assembly version 1.0 , unpublished data ) , l. gigantea ( n = 23,851 , genome assembly version 1.0 , unpublished data ) , trichoplax adhaerens ( n = 11,520 , genome assembly version 1.0 ; srivastava et al .
2008 ) , n. vectensis ( n = 27,273 , genome assembly version 1.0 ; putnam et al .
2007 ) , and ciona intestinalis ( n = 14,002 , genome assembly version 2.0 ; dehal et al .
2002 ) were downloaded from the us department of energy joint genome institute ( http://www.jgi.doe.gov ) . the sea urchin , s. purpuratus , proteins ( n = 28,944 , assembly version 0.5 ; sea urchin genome sequencing consortium 2006 ) were downloaded from the human genome sequencing center at baylor college of medicine ( ftp://ftp.hgsc.bcm.tmc.edu/pub/data ) .
the caenorhabditis elegans proteins ( n = 39,620 , release ws190 ; c. elegans sequencing consortium 1998 ) were downloaded from wormbase ( http://www.wormbase.org ) . the drosophila melanogaster ( n = 20,815 , release 54 ; adams et al .
2000 ) and anopheles gambiae ( n = 13,133 , release 54 ; holt et al .
the h. magnipapillata proteins ( n = 17,398 , assembly version 1.0 ; chapman et al .
protein sets were used to construct 12 mysql databases , which were searched using five amino acid motifs ( table 1 ) that are present in less than 1% of non - or rhodopsin - like gpcrs ( churcher and taylor 2009 ) .
these motifs were derived from a diverse set of lamprey , fish , mammalian , and cephalochordate ors and were selected because of their ability to discriminate between ors and non - ors from the rhodopsin - like gpcr family .
proteins containing a query motif were used in blastp ( altschul et al . 1997 ) searches for paralogs .
sequences that were at least 40% identical to the query sequence over a minimum of 100 amino acids were used in iterative blastp searches until no more genes meeting our search criteria could be identified . only hits to at least part of any of the tm domains were retained ; however , three sequences were excluded because they do not appear to be gpcrs ( s. purpuratus protein 028230 , n. vectensis proteins 205877 and 212306 ) .
proteins with all seven tm domains were considered full - length sequences ; all others were considered partial sequences .
motif - containing sequences and blastp hits were aligned to vertebrate and cephalochordate ors using clustalw ( thompson et al . 1994 ) and the alignment was adjusted by hand in bioedit ( hall 1999 ) . the alignment file is included as supplementary figure s2 ( supplementary material online ) .
the neighbor - joining ( nj ) tree was constructed in mega version 4.0 ( tamura et al . 2007 ) using the pairwise deletion option .
the unrooted nj tree is based on approximately 200 amino acid positions and poisson - corrected distances .
outgroup sequences from the protostomes , deuterostomes , cnidarians , and a placozoan were carefully selected to ensure that , where possible , representatives of the , , , and subgroups of rhodopsin - like gpcrs were included .
the list of sequences can be found in supplementary table s2 ( supplementary material online ) .
nematostella vectensis protein ( 214496 ) is very short and was excluded from the nj tree to allow pairwise distances to be calculated from the alignment .
therefore , figure 1 includes 45 of the 46 n. vectensis or - like genes .
tree topology was confirmed using phyml ( guindon and gascuel 2003 ) and the tree is included in supplementary figure s1 ( supplementary material online ) . to highlight conserved amino acid residues we constructed a weblogo ( crooks et al .
2004 ) from the alignment of 35 full - length n. vectensis or - like genes ( fig .
amino acid residues that are commonly found in fish ( alioto and ngai 2005 ) , mouse ( alioto and ngai 2005 ) , and cephalochordate ors ( churcher and taylor 2009 ) are marked in the figure .
the protein predictions from monosiga brevicollis ( n = 9196 , genome assembly version 1.0 ; king et al .
i ( n = 32,415 , genome assembly version 1.0 , unpublished data ) , helobdella robusta ( n = 23,432 , genome assembly version 1.0 , unpublished data ) , l. gigantea ( n = 23,851 , genome assembly version 1.0 , unpublished data ) , trichoplax adhaerens ( n = 11,520 , genome assembly version 1.0 ; srivastava et al .
2008 ) , n. vectensis ( n = 27,273 , genome assembly version 1.0 ; putnam et al .
2007 ) , and ciona intestinalis ( n = 14,002 , genome assembly version 2.0 ; dehal et al .
2002 ) were downloaded from the us department of energy joint genome institute ( http://www.jgi.doe.gov ) . the sea urchin , s. purpuratus , proteins ( n = 28,944 , assembly version 0.5 ; sea urchin genome sequencing consortium 2006 ) were downloaded from the human genome sequencing center at baylor college of medicine ( ftp://ftp.hgsc.bcm.tmc.edu/pub/data ) .
the caenorhabditis elegans proteins ( n = 39,620 , release ws190 ; c. elegans sequencing consortium 1998 ) were downloaded from wormbase ( http://www.wormbase.org ) . the drosophila melanogaster ( n = 20,815 , release 54 ; adams et al .
2000 ) and anopheles gambiae ( n = 13,133 , release 54 ; holt et al .
the h. magnipapillata proteins ( n = 17,398 , assembly version 1.0 ; chapman et al .
protein sets were used to construct 12 mysql databases , which were searched using five amino acid motifs ( table 1 ) that are present in less than 1% of non - or rhodopsin - like gpcrs ( churcher and taylor 2009 ) .
these motifs were derived from a diverse set of lamprey , fish , mammalian , and cephalochordate ors and were selected because of their ability to discriminate between ors and non - ors from the rhodopsin - like gpcr family .
proteins containing a query motif were used in blastp ( altschul et al . 1997 ) searches for paralogs .
sequences that were at least 40% identical to the query sequence over a minimum of 100 amino acids were used in iterative blastp searches until no more genes meeting our search criteria could be identified . only hits to at least part of any of the tm domains were retained ; however , three sequences were excluded because they do not appear to be gpcrs ( s. purpuratus protein 028230 , n. vectensis proteins 205877 and 212306 ) .
proteins with all seven tm domains were considered full - length sequences ; all others were considered partial sequences .
motif - containing sequences and blastp hits were aligned to vertebrate and cephalochordate ors using clustalw ( thompson et al . 1994 ) and the alignment was adjusted by hand in bioedit ( hall 1999 ) . the alignment file is included as supplementary figure s2 ( supplementary material online ) .
the neighbor - joining ( nj ) tree was constructed in mega version 4.0 ( tamura et al . 2007 ) using the pairwise deletion option .
the unrooted nj tree is based on approximately 200 amino acid positions and poisson - corrected distances .
outgroup sequences from the protostomes , deuterostomes , cnidarians , and a placozoan were carefully selected to ensure that , where possible , representatives of the , , , and subgroups of rhodopsin - like gpcrs were included .
the list of sequences can be found in supplementary table s2 ( supplementary material online ) .
nematostella vectensis protein ( 214496 ) is very short and was excluded from the nj tree to allow pairwise distances to be calculated from the alignment .
therefore , figure 1 includes 45 of the 46 n. vectensis or - like genes .
tree topology was confirmed using phyml ( guindon and gascuel 2003 ) and the tree is included in supplementary figure s1 ( supplementary material online ) .
to highlight conserved amino acid residues we constructed a weblogo ( crooks et al . 2004 ) from the alignment of 35 full - length n. vectensis or - like genes ( fig .
amino acid residues that are commonly found in fish ( alioto and ngai 2005 ) , mouse ( alioto and ngai 2005 ) , and cephalochordate ors ( churcher and taylor 2009 ) are marked in the figure .
supplementary tables s1and s2 and supplementary figures s1 and s2 are available at genome biology and evolution online ( http://www.oxfordjournals.org/our_journals/gbe/ ) . | in vertebrates , olfaction is mediated by several families of g protein coupled receptors ( gpcrs ) including odorant receptors ( ors ) . in this study
, we investigated the antiquity of or genes by searching for amino acid motifs found in chordate ors among the protein predictions from 12 nonchordate species .
our search uncovered a novel group of genes in the cnidarian nematostella vectensis .
phylogenetic analysis that included representatives from the other major lineages of rhodopsin - like gpcrs showed that the cnidarian genes , the cephalochordate and vertebrate ors , and a family of genes from the echinoderm , strongylocentrotus purpuratus , form a monophyletic clade .
the taxonomic distribution of these genes indicates that the formation of this clade and therefore the diversification of the rhodopsin - like gpcr family began at least 700 million years ago , prior to the divergence of cnidarians and bilaterians .
ors and other rhodopsin - like gpcrs have roles in cell migration , axon guidance , and neurite growth ; therefore , duplication and divergence in this family may have played a key role in the evolution of cell type diversity ( including the emergence of complex nervous systems ) and in the evolution of metazoan body plan diversity . |
when the baby boomer generation began to retire , they became a topic of interest in south
korea .
as the retired population of south korea ages , the older adults population continues
to increase faster than in any other country1 . as people age ,
their activity engagement may decrease or
change . continued activity engagement has showed positive effects on healthy life , mental health
and quality of life .
the group based activities in community centres have been associated
with improvements in the health and well being of adults who have previously experienced
poor health and other forms of social disadvantage2 . continued work involvement or volunteerism provides opportunities
for social interaction and engagement , and may be associated with enhanced mental well - being
of older adults3 .
increases in physical
activity has been associated with higher physical self - worth and fewer disability
limitations which have been associated with greater life satisfaction4 . for aging and activity engagement studies to be successful ,
the assessment tool must cover
a lot of activities . ideally , health is a state of adequate physical and mental independence
in activities of daily living5 . in
addition ,
voluntary work , cultural activities , holiday , sports , reading books , hobbies and
shopping are found to be successful predictors of the social connectedness of older
people6 .
the activity card sort ( acs ) is a standardized assessment tool that evaluates the amount
and level of involvement in various activities7 .
the acs consists of labeled photographs of older people
participating in a range of activities and has multiple benefits over existing measures of
participation of older adults , including ease of use , lack of dependency on literacy levels ,
and the inclusion of a broad range of culturally relevant activities8 , 9 .
originally
developed in the usa , the acs now has versions designed for use in israel , hong kong ,
australia , and south korea10,11,12 .
the present study aimed to gain and understanding of activity engagement of aging retirees .
k - acs data was analysed to examine the effect of aging on activity engagement .
data were collected by seven senior university students , who had completed four months of
clinical practice and were trained to administer and score the k - acs .
eligible participants were individuals over 55 years old who could write and communicate in
korean .
candidates were excluded if they had obvious auditory , visual , or cognitive
impairments8 .
the study methods and procedures
were approved by the institutional review board of soonchunhyang university .
the k - acs has three versions : institutional , recovery , and community living .
the community living version requires participants to
sort 67 photographs of activities ( 33 photographs illustrating instrumental activities ,
activities to support daily life within the home and community ; 18 photographs illustrating
leisure activities , nonobligatory activities that is intrinsically motivated and engaged in
during discretionary time ; and 16 photographs illustrating social activities , activities
that are characteristic and expected of an individual in a given position within a social
system ) into 5 categories :
never done , given up , do now , do less , or new activity .
the retained level of activity engagement ( % ) is calculated as follows : level of current activity = values of do now
level of previous activity = values of done previously column ( i.e. , do now
, do less
and given up ) retained level of activity ( by percentage ) = level of current activity / level of previous
activity 100% data were analyzed using spss version 20.0 .
participants were divided into three age groups : 75 years
( group a ) , 6574 years ( group b ) , and 5564 years ( group c ) .
a one - way anova was used to
compare the mean retained level of activity ( mra ) among the three age groups , and scheff s
test was used for post - hoc analyses .
the independent t - tests was used to
examine the significance of gender differences .
95% ci was used and the ` results were
accepted as significant if p<0.05 .
participants were
assigned to the a , b , or c groups to compare the mean levels of activity retained with age .
most participants had completed elementary school ( 85.75% ) and lived in urban communities
( 72.28% ) .
participants rated their health status on a five - point scale , ranging from
excellent to poor .
the same scale was also used to rate each participant s difficulty
with activities of daily living , from not at all to somewhat .
most participants reported
living with a spouse ( 73.06% ) ( table
1table 1 .
general characteristics of the participants ( n=386)numberpercent ( % ) sexmale19049.2female19650.8age556412532.4657413033.775 13133.9highest educationno education5514.2elementary school9524.6middle school8221.2high school11830.6college112.8university205.2graduate school51.3residenceurban27972.3rural10727.7self - rated healthexcellent287.3good13234.2average14738.1poor7920.5self - rated activities of daily living difficultynot at all6015.5not very14337.1neutral9324.1somewhat9023.3living arrangementwith spouse28273.1without spouse10426.9 ) .
the comparison of the mean retained level of activities by agetotala(n=131)b(n=130)c(n=125)instrumental activities68.1 20.681.516.586.616.0**leisure activities71.420.683.219.584.418.3**social activities66.1 26.382.3 23.384.1 20.0 * * : 75 years old , : 6574 years old , :
5564 years old , * * : < 0.01 compared within activities ) .
there were significant differences in the mra between group a and the other
age groups ( instrumental activities , f=36.81 , p<0.01 : leisure activities , f=17.71 ,
p<0.01 , social activities , f=23.24 , p<0.01 ) , but no significant differences were found
between groups b and c ( table 3table 3 .
the comparison of the mean retained level of activities by age and sexageabcinstrumental activitiesmale66.123.677.017.790.112.1(n=41)(n=77)(n=72)female69.019.282.514.681.819.2(n=90)(n=53)(n=53)leisure activitiesmale69.220.785.518.288.513.4(n=41)(n=77)(n=72)female72.320.779.820.979.022.4(n=90)(n=53)(n=53)social activitiesmale67.723.882.123.181.222.4 ( n=41 ) ( n=77 ) ( n=72)female65.427.582.623.779.022.4(n=90)(n=53)(n=53 ) : 75 years old , : 6574 years old , :
5564 years old . * * : < 0.01 compared within activities , : < 0.01
compared between male and female ) . when participants were divided by gender , the same results were obtained
except for the instrumental activities of males and the leisure activities in females . there
were significant differences in mra of instrumental activities between group b and c for
males , but there were no age differences in females of leisure activities .
the independent
t - tests demonstrated significant gender differences of the mra in group c
( table 3 ) .
: 75 years old , : 6574 years old , :
5564 years old , * * : < 0.01 compared within activities : 75 years old , : 6574 years old , :
5564 years old . *
* : < 0.01 compared within activities , : < 0.01
compared between male and female
activity engagement is a natural means of maintaining physical and mental function , and
experiencing well being10 . however ,
activity limitation is a frequent geriatric issue with considerable individual and societal
impacts .
people living with activity limitations may be less likely to experience happiness
or life satisfaction , which can have a negative effect on their quality of life13 .
however , little is known about the age
profile of activity engagement in the south korean retiree population with age .
this study found that activity engagement decreased with age14 . examining the results of each age group
, the most significant
changes appeared mainly in group a. this finding highlights the need for care for older
adults over 75 years to maintain their mra .
it is important to recognize that when activity
participation is changing , there may be health issues that make older adults vulnerable to
functional decline15 .
in contrast ,
engagement in activity acts as a buffer against physical decline in later life16 , 17 .
it is important to know that engagement in activity provides a
health benefit that is as important as physical exercise18 .
in addition , the decreased engagement with age of males in instrumental activities ,
continued engagement of females in leisure activities , and significant gender differences in
mra in group c , suggest the importance of age- , gender- and activity - specific analyses in
order to identify patterns of engagement .
activity choices are affected by changes of life roles because of family dynamics , changes
in living situation , and the deaths of family and friends19 .
all participants were volunteers ; thus , our
sample may not be representative of the entire post - retirement aging population .
second , the
k - acs is a self - report measure , so it may not accurately reflect actual engagement . in
addition , the k - acs measures the numbers of activities , but does not measure the intensity ,
frequency , or duration of each activity20 .
finally , when calculating the retained level of activity , engagement
in new activities was not included in the analyses to identify decreases from previous
levels of activity .
therefore , the mean level of current activity could be higher if new
activities were included in the calculations performed using the original equation . | [ purpose ] the purpose of this study was to analyze the activity engagement of the
retiree population in south korea .
[ methods ] the korean - activity card sort ( k - acs ) was
used to collect research data . a one - way anova and
post - hoc comparisons showed significant
group effects among three age groups .
the independent t - tests was used to analyze the
differences in mean retained level of activity ( mra ) between men and women .
[ results ] the
one - way anova showed statistically significant differences in mra among different age
groups .
scheff s test revealed a statistically significant decrease in mra in group a ,
aged more than 75 years , as compared to the other two age groups .
when participants were
divided by gender , mra of instrumental activities showed a statistically significant
difference between the 6574 years group and the 5565 years group , but no difference in
females of the leisure activities among the age groups .
the independent t - tests
demonstrated significant gender differences in mra of activity of the 5564 years group .
[ conclusion ] these findings suggest that health professionals should monitor the changes
in retained level of activity after age 75 , to maintain their engagement , and the
importance of age- , gender- and activity - specific analyses in order to identifying
patterns of activity engagement . |
in bacterial and archaeal genomes , about one half of all protein - coding genes are organized into operons .
( 1 ) . but even for the other half , conservation of the genomic context i.e. the genes upstream and downstream on the chromosome , is observable between related species ( 2 )
. the genomic context can provide important information about duplication , insertion , translocation or deletion events . while the past decades have equipped scientists with a broad range of excellent bioinformatics tools for analysis and comparison of single protein sequences ,
taking a step back and looking at the bigger genomic picture and comparing it between different organisms is still largely manual work . for many well annotated proteins and operons , databases like biocyc ( 3 ) ,
string ( 4 ) , the seed ( 5 ) or ensembl bacteria ( 6 ) can provide important information .
however , looking beyond the content of those databases to extend the search into more genomes or investigating less well - characterized proteins can be challenging .
gcview , the genomic context viewer for protein homology searches aims to ease and automate the manual process of extracting and comparing genomic regions of interest .
it is integrated into the bioinformatics toolkit of the max - planck institute for developmental biology ( mpi toolkit ) ( 7 ) and can be accessed through a user - friendly web interface at http://toolkit.tuebingen.mpg.de/gcview .
this website is free and open to all users and there is no login requirement .
the underlying homology information is taken from standard protein homology search tools like blastp or psi - blast ( 8) . in contrast to the above mentioned databases such as string , the homology searches are not precomputed , giving the user full control over and insight into the processes leading to the final result .
gcview can integrate multiple searches ( e.g. one for each component of an operon ) and compile a comprehensive overview of the combinatorial variants found in different genomes .
the results can be mapped onto a taxonomy tree for a quick overview of the distribution of operon structures throughout all sequenced procaryotic organisms .
the output is a series of images showing the genomic regions that contain the genes of interest .
additionally , for each image a list of the encoded proteins is provided that contains additional information such as descriptions and database links .
the integration into the mpi toolkit allows users to run homology search jobs independent of gcview , providing maximum control over the input parameters , and then to internally forward the results to gcview for integration .
consequently , the results from gcview can also be forwarded to other specialized tools for a more detailed analysis of subsets of proteins or genes .
all results are stored on the server for 2 weeks and can be revisited and reviewed at a later time point .
it is possible to create an account on the mpi toolkit , which allows jobs to be bound to the account and saved for extended periods of time .
the design goal for gcview was to provide a quick and accurate overview of the combinatorial variants of operons in different genomes based on well established homology search methods accessible through a user - friendly straightforward web interface .
gcview accepts several different types of input : fasta protein sequences , protein gi or uniprot identifiers and forwarded homology search jobs .
currently gcview is limited to protein homology searches or protein sequences as input , mostly due to the higher sensitivity of protein searches compared to dna searches .
it is possible to use not only full protein sequences , but also single domains as query for the search .
if , alternatively , fasta sequences or protein identifiers are provided , gcview internally executes a psi - blast run for each sequence or identifier provided and analyzes the results .
additional input parameters are the size of the genomic region to be displayed and the e - value cutoffs for the results to be included in the output .
the size of the genomic region is interpreted as the number of genes to be extracted before the first hit and after the last hit in any genome .
note that the quality of the gcview results strongly depends on the underlying homology search being exhaustive , i.e. containing results at least up to the e - value cutoff specified for gcview .
this is especially important in group view : only exhaustive searches lead to a maximum of labeled operon components .
operons with unlabeled components lead to additional groups , which would not be observed after an exhaustive search . for the same reason , caution is advised when using blast databases prefiltered at a certain sequence similarity cutoff . for technical reasons , it is only possible to use blast databases , which contain gi or uniprot identifiers .
using a database which does not provide appropriate identifiers in the output will not give any results in gcview .
from each input homology search , a list of protein gi numbers is extracted along with the exact region and degree of similarity .
the lists are filtered for proteins with e - values below the threshold specified in the input and for proteins from organisms which have not been fully sequenced .
the backend database of sequenced genome data is built from the genomes found in ncbi genbank ( 9 ) ( ftp://ftp.ncbi.nih.gov/genomes/bacteria ) and comprises fully sequenced bacterial and archaeal genomes .
for each hit the genes upstream and downstream of the hit are extracted from the database , resulting in one genome chunk for each hit .
this implies that an operon which has been duplicated in a genome can show up as one or two chunks , depending on the distance between the duplicates and the range settings . after merging ,
gcview accepts several different types of input : fasta protein sequences , protein gi or uniprot identifiers and forwarded homology search jobs .
currently gcview is limited to protein homology searches or protein sequences as input , mostly due to the higher sensitivity of protein searches compared to dna searches .
it is possible to use not only full protein sequences , but also single domains as query for the search .
if , alternatively , fasta sequences or protein identifiers are provided , gcview internally executes a psi - blast run for each sequence or identifier provided and analyzes the results .
additional input parameters are the size of the genomic region to be displayed and the e - value cutoffs for the results to be included in the output .
the size of the genomic region is interpreted as the number of genes to be extracted before the first hit and after the last hit in any genome .
note that the quality of the gcview results strongly depends on the underlying homology search being exhaustive , i.e. containing results at least up to the e - value cutoff specified for gcview .
this is especially important in group view : only exhaustive searches lead to a maximum of labeled operon components .
operons with unlabeled components lead to additional groups , which would not be observed after an exhaustive search . for the same reason , caution is advised when using blast databases prefiltered at a certain sequence similarity cutoff . for technical reasons , it is only possible to use blast databases , which contain gi or uniprot identifiers . using a database which does not provide appropriate identifiers in the output will not give any results in gcview .
from each input homology search , a list of protein gi numbers is extracted along with the exact region and degree of similarity .
the lists are filtered for proteins with e - values below the threshold specified in the input and for proteins from organisms which have not been fully sequenced .
the backend database of sequenced genome data is built from the genomes found in ncbi genbank ( 9 ) ( ftp://ftp.ncbi.nih.gov/genomes/bacteria ) and comprises fully sequenced bacterial and archaeal genomes . for each
hit the genes upstream and downstream of the hit are extracted from the database , resulting in one genome chunk for each hit .
this implies that an operon which has been duplicated in a genome can show up as one or two chunks , depending on the distance between the duplicates and the range settings . after merging ,
gcview generates two different views for the results : the group view and the taxonomy view .
figure 2 shows example outputs for both views for two different runs of gcview .
the lac operon ( demo data ) is shown in group view with one group expanded .
potra domains from omp85 and related proteins ( 10 ) in different organisms shown in group view .
the lac operon ( demo data ) is shown in group view with one group expanded .
potra domains from omp85 and related proteins ( 10 ) in different organisms shown in group view .
a group comprises all organisms which contain a specific number and order of the genes of interest .
a schematic image of each group summarizes which of the genes of interest can be found in the group and in which order they appear in the genome . each query gene
the colors are explained in the legend , which is displayed on the top of the page .
the arrows in the group view are not to scale and the colors do not indicate the degree of identity between query and hit sequences . fused arrows indicate that multiple query sequences were mapped onto one gene .
gray boxes represent one or multiple genes that are not homologous to any of the query sequences but located between genes of interest .
the groups can be expanded to view the detailed genomic context for each organism in the respective group .
the numbers next to the organism names represent the number of hits in this taxon and its sub - groups .
the detailed information for each hit can be viewed at the leaves of the tree .
each representation contains a genome i d , indicating the nucleotide gi number of the genome from which the corresponding region was extracted . in the case that genes of interest are located in several non - overlapping regions of the same genome ( e.g. due to operon duplication ) ,
multiple representations with the same nucleotide i d are shown , one for each region .
a schematic image of the region shows the genetic neighborhood of the genes of interest .
regions of homology to the genes of interest are highlighted in the corresponding colors , which are indicated in the legend .
in contrast to the group view , the intensity of the color corresponds to the identity score of the hit and the arrow length correlates with the length of the gene .
various details for each gene ( description , precise location , length , distance to neighboring genes ) can be viewed by hovering the mouse over the arrows .
clicking on an arrow expands a detailed list of the genes in the image and the search hits therein . the selected gene is highlighted in the list . a clipboard widget located in the right corner of the screen
these genes can be forwarded to sequence retrieval tools for further analysis or used in another gcview run for an iterative expansion of the set of analyzed genes .
we present gcview , an interactive web tool for automated retrieval and comparison of the genomic context of protein - coding genes .
the underlying homology searches use protein sequences instead of dna for higher sensitivity . compared to classical databases like the seed or biocyc ,
the advantages of gcview are : ( i ) a greater focus on the query , as only the homologs of the input proteins are highlighted , and the degree of similarity is easily visible from the output ; ( ii ) interactivity , as the query can iteratively be extended by more proteins of interest ; ( iii ) transparency , as the user can have full control over the parameters of the underlying homology search ; and ( iv ) flexibility , as e.g. single domains can be used as query , revealing different domain contexts .
gcview is embedded into the mpi toolkit , which allows users to save their gcview runs for later reinspection and directly analyze the genes found by gcview using a broad range of sequence and structure analysis tools .
funding for the project as well as for open access charge : departmental funding of the max planck society . | genomic neighborhood can provide important insights into evolution and function of a protein or gene .
when looking at operons , changes in operon structure and composition can only be revealed by looking at the operon as a whole . to facilitate the analysis of the genomic context of a query in multiple organisms we have developed genomic context viewer ( gcview ) .
gcview accepts results from one or multiple protein homology searches such as blastp as input . for each hit , the neighboring protein - coding genes are extracted , the regions of homology are labeled for each input and the results are presented as a clear , interactive graphical output .
it is also possible to add more searches to iteratively refine the output .
gcview groups outputs by the hits for different proteins .
this allows for easy comparison of different operon compositions and structures .
the tool is embedded in the framework of the bioinformatics toolkit of the max - planck institute for developmental biology ( mpi toolkit ) .
job results from the homology search tools inside the mpi toolkit can be forwarded to gcview and results can be subsequently analyzed by sequence analysis tools .
results are stored online , allowing for later reinspection .
gcview is freely available at http://toolkit.tuebingen.mpg.de/gcview . |
one type of brain mechanism subserving sensory - motor coordination is referred to as internal action models ( iams ) .
iams are brain templates that allow action initiation based on sensory expectations alone and ongoing refinement of motor output based on sensory input flow .
human olfaction is subserved by the sniff response where unpleasant and intense odors are sampled with low - magnitude sniffs , but pleasant and mild odors are sampled with high - magnitude sniffs [ 810 ] . because the sniff response entails fine adjustment of a motor process ( the sniff ) in precise accordance with sensory input ( the odor ) , it can be considered an iam . here , we set out to test the hypothesis that the sniff response will be altered in children with asd .
notably , we do not hypothesize that children with asd will be unable to sniff , but rather that they will generate an inappropriate sniff given a particular odor .
in other words , we do not hypothesize a motor impairment per se , but rather impairment in iam - dependent sensory - motor coordination . to measure the sniff - response in children
, we built a computer - controlled air - dilution olfactometer equipped with a custom - designed double - barreled pediatric nasal cannula that allowed us to simultaneously deliver odors and measure nasal airflow ( figure 1 ) .
we used this apparatus to precisely measure the sniff response following pleasant ( rose or shampoo ) and unpleasant ( sour milk or rotten fish ) odors in 18 children with asd ( 17 boys , mean age = 7 2.3 ) and 18 age- and gender - matched typically developing ( td ) children ( 17 boys , mean age = 6.7 2.1 ) as controls ( table 1 ) . the 10-min procedure consisted of 20 trials ( 10 of each valence ) , each 12 s in duration , separated by a 30-s intertrial interval . during the paradigm ,
, we extracted four sniff parameters : sniff volume , peak airflow rate , mean airflow rate , and duration .
a multivariate repeated - measures anova applied to all parameters revealed a significant interaction between odorant valence ( pleasant versus unpleasant ) and group ( td versus asd ) ( f1,34 = 4.47 , p < 0.05 ) , reflecting larger sniffs for pleasant versus unpleasant odors in td alone .
this was evident in a point - by - point comparison of the sniff traces revealing that td children altered their sniff to account for odorant properties within 305 ms of sniff onset ( at 305 ms , flow pleasant = 0.918 0.32 normalized flow units [ nfu ] , flow unpleasant = 0.665 0.22 nfu , t17 = 3.68 , p < 0.0019 , equivalent to p < 0.05 bonferroni corrected for the multiple t tests ) and maintained this or greater difference 680 ms into the sniff response ( dotted line , figure 2a ) .
in contrast , asd sniffs did not significantly differ by odor at any point along the sniff trace ( figure 2b ) .
in addition , a three - way interaction between sniff parameters , odorant valence , and group ( f3,102 = 6.16 , p <
0.001 ) revealed the same effect materialized individually in three of the four parameters we extracted ( e.g. , volume = f1,34 = 4.2 , p < 0.05 ; td : normalized sniff volume : pleasant = 1.07 0.3 normalized volume units [ nvu ] , unpleasant = 0.79 0.22 nvu , t17 = 4.73 , p < 0.0005 ; asd : pleasant = 0.95 0.33 nvu , unpleasant = 0.99 0.64 nvu , t17 = 0.36 , p = 0.72 ; same effects for mean and peak airflow , both f1,34 > 4.2 , both p < 0.05 ) ( figure 2c ) . no other significant main effects or interactions were found ( all p > 0.11 ) . in other words , consistent with our hypothesis , td children exhibited an adult - like sniff response , but asd children did not activate the olfactory iam to adjust their sniff in accordance with odorant properties . a key characteristic of this approach is that it does not depend on verbal comprehension .
nevertheless , we later used a child - friendly visual - analog scale ( vas ) to obtain odorant pleasantness estimates from the participants . whereas 17 of the 18 td children provided such estimates directly after testing , only 3 of the 18 asd subjects agreed to do the same .
an additional nine of the asd children agreed to provide these estimates when approached at a later date . in td ,
the sniff response was a strong predictor of perceived explicitly reported pleasantness ( r = 0.74 , p < 0.001 ; figure 2d , green ) . in turn , although there were no differences in reported pleasantness between td and asd ( u = 81 , p = 0.37 ) , the sniff response was unrelated to perceived explicitly reported pleasantness in asd ( r = 0.31 , p = 0.34 ; figure 2d , orange ) .
the vas reports obtained from children , both td and asd , are not highly reliable in our view . nevertheless , these reports implied that both td and asd children perceived the pleasant and unpleasant odors as intended , but only the td children modulated their sniff accordingly .
we next tested whether the altered sniff response in asd can differentiate asd from td children at a single - subject level .
we used a multivariate normal density classifier applied to the sniff parameters and found that a classifier relying on the differences in pleasant versus unpleasant sniff duration combined with the sniff volume for unpleasant odors effectively distinguished td from asd children . using a leave - one - out analysis ,
the classifier correctly identified 17 of 18 td children as well as 12 of 18 asd children , i.e. , one false positive and six false negatives ( 81% accuracy , binomial p < 0.001 ) ( figure 3a ) .
in contrast to a group difference alone , this power at the single - subject level implies that an altered sniff response is a genuine part of asd . finally , to determine whether the sniff response informs on asd beyond classification alone , we correlated the sniff response with independently obtained autism severity scores ( autism diagnosis observation schedule [ ados ] ) .
we found a strong correlation in several sniff - response parameters , most notably in sniff duration , reflecting that within the asd group , more aberrant sniffing ( longer sniff durations for unpleasant versus pleasant odors ) was associated with an increase in autism severity ( r = 0.75 , p < 0.0005 ) ( figure 3b ) .
notably , this correlation between the sniff - dependent measure and ados scores is very similar to the ados test retest correlation . to further investigate this link between autism severity and the sniff response
, we looked at separate components of the non - olfactory tests we conducted .
we found that the sniff response remained highly predictive of the social affect component of ados ( r = 0.72 , p < 0.001 ) ( figure 3c ) , but it was unrelated to the restricted and repetitive behavior component of ados ( r = 0.18 , p = 0.47 ) .
notably , there was a trend toward a correlation between social affect component of ados and iq ( r = 0.42 , p < 0.09 ) and , indeed , an ensuing trend toward a correlation between the sniff response and iq ( r = 0.55 , p < 0.06 ) .
in other words , the sniff - response measure is reflective of the mechanism involved with the social impairment that is at the heart of asd . finally , to determine whether the sniff response merely reflected a generalized motor impairment , we first compared it to the separately obtained motor score from the vineland adaptive behavior scale ( vabs ) and found no relation at all ( r = 0.12 , p = 0.68 ) ( figure 3d ) .
altered sniffing was unrelated to the other vabs subscales as well ( communication : r = 0.22 , p = 0.39 ; daily living : r = 0.22 , p = 0.39 ; social : r = 0.07 , p = 0.78 ) .
given that the vabs depends on parental reports rather than direct testing , and its social score was unrelated to the ados social score in our study ( r = 0.13 , p = 0.61 ) and several previous studies [ 17 , 18 ] , we further assessed the relation to basic motor performance by conducting direct testing .
we re - approached the children with asd using a previously described battery of simple motor tests including a finger tapping test ( ftt ) , strength of grip ( sog ) , and a modified pegboard test ( mpt ) . like the vabs motor subscale , we found that performance on these tests was unrelated to the sniff response ( ftt : r = 0.11 , p = 0.71 ; sog : r = 0.1 , p = 0.72 ; mpt : r = 0.38 , p = 0.18 ; figure 3e ) .
in other words , the degree of alteration in the asd sniff response was unrelated to the level of basic motor performance .
these results imply an altered olfactory response that is evident in children with asd and is more pronounced with increased autism severity .
this implies that olfaction , which may serve in asd intervention , may also provide for a novel early non - verbal non - task - dependent asd marker .
moreover , even when altered olfaction was detected in asd , whether it was present early in the asd cascade or was the result of life with asd was unknown .
one possible reason for the differences across previous asd olfaction studies and for the unknown developmental time course is the verbal and task - dependent nature of standard olfactory tests .
these typically entail following verbal or written time - locked instructions and providing verbal or written answers .
this clearly prevents testing at pre - verbal ages and is further susceptible to asd - related differences in comprehension , motivation , and general task - related parameters .
the sniff response is largely devoid of these limitations , as it consists of a language - free task - free automatic odor - specific response .
this allowed us to answer the above questions as follows : olfaction is genuinely altered in asd , this alteration is evident early in the asd cascade ( childhood ) , and it is related to autism severity .
notably , the sniff response is similar across humans and rodents . given this , the language - free task - free nature of this paradigm also renders it a promising benchmark candidate for future testing of asd animal models that can directly be compared to humans in this respect .
second , an important open question of whether this marker is specific to asd or common across various developmental disorders remains .
given the trend toward a correlation between iq and sniff response in the asd group , this link deserves further investigation .
finally , several technical issues ( such as compliance ) need to be addressed before this could become a useful tool in clinics . in turn
, these findings also support an emerging theory regarding the mechanisms of asd and potentially link this theory to the hallmark symptom of asd .
specifically , the impaired - iam theory of asd has been linked to altered brain connectivity in asd ( although the extent of altered connectivity in asd remains unclear [ 32 , 33 ] ) .
indeed , the sniff response likely depends on large - scale connectivity between ventral temporal olfactory cortex where odor valence is processed [ 34 , 35 ] and cerebellar circuits where the sniff response is likely actuated [ 36 , 37 ] .
coincidently , these ventral temporal and cerebellar substrates of olfaction are in fact neural substrates specifically implicated in asd [ 38 , 39 ] .
thus , the results obtained here are supportive of the notion that impaired iams are at the mechanistic root of asd .
impaired iams subserving visual gaze and socially relevant eye fixation targets may partially underlie the social impairments in asd , giving rise to an asd - type theory of mind . here
, we end in speculating that our results offer a novel additional possible link between impaired iams and the social impairment of asd .
specifically , increasing evidence implies that social chemosignaling is a meaningful component of human social interaction [ 42 , 43 ] .
critically , olfaction and odor are used to gage and influence the emotions of others and thus play a meaningful role in social communication .
we propose that the altered iam that is the sniff response leads to altered olfaction , which contributes to impaired social communication .
consistent with this hypothesis , the degree of alteration in sniff response was predictive of impaired social communication ( figure 3c ) , but not of generalized motor impairment ( figures 3d3 g ) .
in other words , we end in hypothesizing that the measure we have uncovered links a proposed mechanism of asd ( impaired iams ) with the primary phenotype of asd ( impaired social communication ) .
legal guardians ( all were parents ) of all participants signed informed consent to procedures approved by both the assaf harofe medical center and israeli national helsinki committees .
exclusion criteria for all children were organic smell disturbances or acute respiratory infection and for td children a social communication questionnaire ( scq ) score of above 11 .
to estimate the number of participants to enroll , we conducted a power analysis based on means and sds in healthy adults ( healthy controls in ) . given previous odorant - dependent changes in sniff volume from 60.65 to 55.54 5 nvu , at power = 0.8 and alpha = p < 0.05 , power analysis implied at least 17 participants in each group .
we therefore studied 18 children with asd ( 17 boys , mean age = 7 2.3 ) ( this gender bias reflected the underlying population at the autism center ) and 18 td controls ( 17 boys , mean age = 6.7 2.1 ) .
the td and asd groups did not significantly differ in age ( t34 = 0.51 , p = 0.61 ) , gender ( fisher s exact test p = 1.0 ) , or parental education ( t63 = 1.22 , p = 0.23 ) .
notably , only about one in four children approached at the autism center agreed to participate .
this raises a selection bias concern whereby perhaps only a specific subset of asd ( those who agreed ) was tested . to address this , we obtained all the non - olfactory measures ( e.g. , ados scores , iq , vabs , etc . ) from the children who were approached , but not tested , and compared these to the tested group .
we found no differences between the two groups ( f9,70 = 1.59 , p = 0.13 ) .
the child was comfortably seated in front of a computer monitor viewing a cartoon and fitted with a custom - designed double - barreled pediatric nasal cannula that both delivered odors from a computer - controlled air - dilution olfactometer and measured the nasal airflow of the sniff response ( figure 1 ) . the 10-min procedure consisted of 20 trials ( 10 for each valence ) ,
we used two pairs of odorants , one mono - molecular ( pleasant phenyl - ethyl alcohol [ pea ] , undiluted , cas 60 - 12 - 8 , sigma - aldrich and unpleasant butyric acid , diluted at 30% in odorless propane-1,2-diol , cas 107 - 92 - 6 , sigma - aldrich ) and one of complex mixtures ( pleasant herbal essence and unpleasant rotten fish , both from senseale , ramat gan , israel ) .
both pairs of odorants were presented at similar subjective intensity as rated by adult raters .
the same result materialized for both odor pairs . to obtain explicit odor ratings , children sniffed the odors from jars and rated their pleasantness using a six - point vas where each point was also denoted by a
smiley , ranging from a happy face associated with pleasant to a sad face associated with unpleasant .
to assess general motor performance in asd , we conducted three tasks : an ftt , sog , and mpt .
the ftt consisted of using the index finger to tap on a board - mounted manual counter as many times as possible within 10 s. the task was repeated twice with each hand ; the totals from all trials were averaged for both hands combined .
if the two trials were not within 5 points , a third trial was completed , and the average of three trials was used .
the sog was measured using a hand dynamometer ( neulog , ses scientific educational systems ) that the subjects held in the palm of their hand and squeezed as tightly as possible .
strength ( in kilograms ) was recorded in three trials for each hand and averaged .
the total sog score was computed by combining the means of both hands . in the mpt
, the participant was required to insert pegs in a grooved board in a specific directionality as quickly as possible using the dominant and non - dominant hand separately .
the modification was in the number of pegs used ( 18 instead of 25 ) and type of pegs ( two - colored wooden pegs ) .
the score was the time required to place all 18 pegs into the holes ( timing was not interrupted in the event of a dropped peg ) .
nasal airflow was measured continuously . to account for variation across subjects stemming from such factors as cannula placement , we normalized each odorant sniff by dividing it by the average of three non - odorant nasal inhalations that preceded it .
data were then analyzed using matlab ( mathworks , version r2013a ) and statistica ( statsoft , version 7 ) .
differences in sniff response between pleasant and unpleasant odors were first estimated by conducting a t test on every time point of the ongoing respiratory trace ( dotted black line in figure 2 ) .
we corrected for the number of t tests as follows : the sniff response in adults materialized within 160 ms , so we down - sampled the recording to just above the relevant nyquist range , namely 16.667 hz .
given an average sniff of about 1.5 s , this translates to 25 comparisons per sniff ( 16.667 1.5 ) .
thus , we bonferroni corrected for 25 comparisons ( green line in figure 2 ) .
next , differences in sniff response between pleasant and unpleasant odors and specific sniff parameters as a function of group ( asd / td ) were estimated using a multivariate repeated - measures anova with conditions of sniff parameter ( mean airflow , airflow peak , sniff duration , and sniff volume ) , odorant valence ( pleasant or unpleasant ) , and group ( asd or td ) .
this was followed by repeated - measures anovas and t tests for each sniff parameter alone . when classifying asd and td based on this data , each attempt to classify a subject is a bernoulli trial with even odds of success and failure .
therefore , the probability of correctly classifying 29 out of 36 subjects is given by : p=(12)36(3629)<0.001 this is therefore the statistical power of our classification result .
finally , correlation between the sniff response and autism measures was assessed using the spearman correlation coefficient .
| summaryinternal action models ( iams ) are brain templates for sensory - motor coordination underlying diverse behaviors [ 1 ] .
an emerging theory suggests that impaired iams are a common theme in autism spectrum disorder ( asd ) [ 24 ] .
however , whether impaired iams occur across sensory systems and how they relate to the major phenotype of asd , namely impaired social communication [ 5 ] , remains unclear .
olfaction relies on an iam known as the sniff response , where sniff magnitude is automatically modulated to account for odor valence [ 612 ] . to test the failed iam theory in olfaction , we precisely measured the non - verbal non - task - dependent sniff response concurrent with pleasant and unpleasant odors in 36 children18 with asd and 18 matched typically developing ( td ) controls .
we found that whereas td children generated a typical adult - like sniff response within 305 ms of odor onset , asd children had a profoundly altered sniff response , sniffing equally regardless of odor valance .
this difference persisted despite equal reported odor perception and allowed for 81% correct asd classification based on the sniff response alone ( binomial , p < 0.001 ) .
moreover , increasingly aberrant sniffing was associated with increasingly severe asd ( r = 0.75 , p < 0.001 ) , specifically with social ( r = 0.72 , p < 0.001 ) , but not motor ( r < 0.38 , p > 0.18 ) , impairment .
these results uncover a novel asd marker implying a mechanistic link between the underpinnings of olfaction and asd and directly linking an impaired iam with impaired social abilities . |
leprosy , a disease of high endemicity in india , is claimed to be showing a decline in mean prevalence in the country . however , the detection of new cases is relatively static and it has been observed that clinical manifestations of leprosy appear to be changing .
this poses a great challenge for clinicians to diagnose leprosy in time and initiate therapy to prevent complications of untreated disease . during the last four years
, we have encountered cases presenting with predominantly neural manifestations with no or minimal cutaneous manifestations .
we share our experience related to 10 such cases that we studied retrospectively in last few years which probably could have been difficult to detect in a field situation .
the study was conducted at the main referral center and satellite clinics of our organization .
the center carries out operational and clinical research along with providing outpatient management of both referred and self - reporting leprosy cases and reaction management .
the patients seen are self - reporting as well as referred to the center from other hospitals , private clinics , and peripheral centers .
these cases were referred basically for diagnostic reasons and were selected for study in view of unusual presenting features which made the diagnosis of leprosy difficult with routine methods .
all patients were subjected to a detailed clinical examination by trained medical officers and to a bacteriological examination with slit - skin smears .
higher investigations like electromyography ( emg)/nerve conduction studies ( ncs ) and nerve biopsy were done in seven patients .
a 40-year - old female was referred with complaints of blisters on the right arm , forearm , and hand since two years .
the patient had a history of tingling numbness in the right upper and lower extremity dating six years back .
she was investigated with magnetic resonance imaging ( mri ) of the spine and emg / ncs three years before she was referred to our clinic . on examination
, she was found to have a thickening of the right ulnar , median , and radial cutaneous nerves , and both posterior tibial nerves .
repeat emg / ncs showed no sensory conduction in the right median , ulnar , radial , and both sural nerves , whereas amplitude and motor conduction velocity was reduced in the right median and both ulnar nerves .
laboratory investigations like hemogram , chest x - ray , urinalysis , liver function tests , renal function tests , and blood glucose levels were within normal limits .
finally , a biopsy of the left sural nerve was done which revealed three enlarged fascicles with a large number of infiltrating cells comprising lymphocytes , plasma cells , and macrophages in the endoneurium .
small clumps of acid - fast bacilli were seen in a good number of cells . a borderline lepromatous type of nerve lesion with evidence of type 1 reaction was diagnosed .
a 38-year - old male , nondiabetic , was referred to our center for a slit - skin smear .
the patient had a history of loss of sensation on the lateral aspect and heel of the left foot since three months .
past and family history was negative for neuropathy or leprosy . on examination , fine touch sensation was absent , whereas crude touch sensation was diminished in the left lower extremity .
left ulnar nerve , lateral peroneal , anterior tibial , and sural nerves were thickened .
a diagnosis of leprosy was doubtful with such a short duration of complaints but emg / ncs done before the patient was referred to us demonstrated left sural neuropathy .
therefore , a left sural nerve biopsy was done which showed granulomas comprising lymphocytes , macrophages , and epithelioid cells within and around fascicles
a 40-year - old female was referred with complaints of blisters on the right arm , forearm , and hand since two years . the patient had a history of tingling numbness in the right upper and lower extremity dating six years back .
she was investigated with magnetic resonance imaging ( mri ) of the spine and emg / ncs three years before she was referred to our clinic . on examination , she was found to have a thickening of the right ulnar , median , and radial cutaneous nerves , and both posterior tibial nerves .
repeat emg / ncs showed no sensory conduction in the right median , ulnar , radial , and both sural nerves , whereas amplitude and motor conduction velocity was reduced in the right median and both ulnar nerves .
laboratory investigations like hemogram , chest x - ray , urinalysis , liver function tests , renal function tests , and blood glucose levels were within normal limits . finally , a biopsy of the left sural nerve was done which revealed three enlarged fascicles with a large number of infiltrating cells comprising lymphocytes , plasma cells , and macrophages in the endoneurium .
small clumps of acid - fast bacilli were seen in a good number of cells . a borderline lepromatous type of nerve lesion with evidence of type 1 reaction was diagnosed .
a 38-year - old male , nondiabetic , was referred to our center for a slit - skin smear . the patient had a history of loss of sensation on the lateral aspect and heel of the left foot since three months .
past and family history was negative for neuropathy or leprosy . on examination , fine touch sensation was absent , whereas crude touch sensation was diminished in the left lower extremity .
left ulnar nerve , lateral peroneal , anterior tibial , and sural nerves were thickened .
a diagnosis of leprosy was doubtful with such a short duration of complaints but emg / ncs done before the patient was referred to us demonstrated left sural neuropathy .
therefore , a left sural nerve biopsy was done which showed granulomas comprising lymphocytes , macrophages , and epithelioid cells within and around fascicles .
of the 10 cases , six were males and four females , their age ranging from 11 to 63 years .
demographic , clinical , and laboratory features of patients nerve biopsy findings figure 1 shows the main presenting complaints of the patients and the number of patients having the complaints . presenting complaints of patients figure 2 shows the mode of diagnosis of leprosy in the patients . clinically thickened nerves were found in nine patients out of ten .
slit - skin smear was negative in all cases except case 10 [ figures 3 and 4 ] . in one patient ( illustrative case 1 ) , the diagnosis was not done for six years despite several higher investigations like mri and so on .
ulcerative lesion on left forearm of patient 10 ulcerative lesion on right leg of patient 10 the diagnosis of leprosy could be confirmed in all the 10 cases , of which seven were diagnosed by nerve biopsy alone [ figures 5 and 6 ] .
one case ( case 9 ) was diagnosed clinically based on findings of thickening of the digital cutaneous nerve of the right hand ( a rare finding ) and extensive family history of leprosy .
histopathology of nerve biopsy of patient 3 ( h and e , 100 ) borderline tuberculoid - midborderline type of disease in the nerve ( h and e , 400 ) in one case , ultrasonography ( usg ) of the nerve was also done .
leprosy is a chronic infectious disease of the skin and nerves caused by mycobacterium leprae .
it is an ancient disease which is now evolving in terms of its presentation and clinical scenarios .
most of the cases are still being diagnosed by classical presenting features such as hypopigmented , anesthetic patches , thickened nerves , and finding acid - fast bacilli on slit - skin smears and skin biopsies .
however , cases are also being seen with predominantly neurological manifestations and also uncommon manifestations with none or few of the classical presentations .
these conditions may be confused with other neurological disorders and the diagnosis of leprosy may be missed or delayed .
noordeen et al . has described pure neural leprosy as being characterized by neuropathic symptoms and thickened nerves with or without motor and sensory loss , in the absence of any cutaneous manifestation of leprosy .
although the patients with no obvious skin lesions may be fewer in proportion than those with skin involvement ( ranging from 4 to 16% ) , their detection and treatment are vital in preventing deformities , and if the classical diagnostic criteria are used for diagnosis of leprosy , then many cases are bound to be overlooked .
according to the latest statistics of the world health organization ( who ) on leprosy , india is still the largest contributor to the global patient load of leprosy . with elimination of leprosy being
the aim , early diagnosis and prompt therapy of the patients holds the key . any delay in diagnosis and initiation of appropriate therapy
is not being detected by the usual methods in a subset of patients , higher diagnostic tests such as nerve biopsy have to be used on a routine basis for such patients .
nerve biopsy has proved to be a more sensitive and revealing test than skin biopsy alone .
the efficacy of nerve biopsy as a diagnostic tool , especially when skin lesions are absent , has been proved previously .
the usefulness of nerve biopsy over skin biopsy in the diagnosis of leprosy has also been demonstrated earlier . in cases of mononeuropathy without a known etiology and without skin changes suggestive of leprosy , de freitas et al . recommended superficial nerve biopsy as a mandatory procedure to confirm leprosy mainly in developing countries where it is prevalent .
kaur et al . , in their study of 108 neuritic leprosy patients , have documented that nearly two - thirds of the patients had a moderate to heavy bacterial load within the nerves despite all the patients having a negative skin smear .
gabelle et al . have documented a case in france which presented with a slowly progressive asymmetric axonal sensory - motor neuropathy , where the diagnosis was made after a delay of eight years with the help of a nerve biopsy .
patients with complaints of predominantly neural manifestations such as tingling numbness , anesthesia , and nonhealing ulcers are more likely to visit neurologists and/or surgeons for treatment .
our study highlights that cases of neural leprosy are still very much present in the general population and therefore clinical suspicion of leprosy needs to be kept in mind .
the diagnosis may be confirmed by a nerve biopsy , a relatively simple procedure with high diagnostic efficacy , which should be done promptly to establish the diagnosis and initiate the appropriate therapy without delay .
this study was done with the aim of bringing neural leprosy to the attention of neurologists , dermatologists , and leprologists alike .
the interest in these cases was due to the fact that the diagnosis of leprosy on clinical grounds and routine testing was truly challenging and one had to resort to further investigations like nerve conduction studies and , nerve biopsies to confirm the diagnosis .
india being an endemic region for leprosy , it is of paramount importance that differential diagnosis of leprosy be considered when faced with such cases in a busy outpatient neurology and dermatology setting .
it is possible therefore , that many such patients with primary neurological complaints are likely to be seen and diagnosis either could be delayed or missed resulting in nerve damage and its consequences , if not thought of or investigated to confirm leprosy . | background : leprosy is a disease of declining global endemicity but is still an important health - care problem in india .
pure neural leprosy is an important subset of presentations of leprosy in india .
leprosy is a known disease of the skin and nerves , but cases of pure neural involvement are relatively less .
we hereby present 10 cases of pure neural leprosy in which the diagnosis of leprosy was difficult with routine methods.materials and methods : the study was conducted at the main referral center and satellite clinics of our organization .
a retrospective analysis of patient records for the last four years was undertaken to identify patients presenting with predominantly neurological manifestations and uncommon presentations including those without skin lesions .
the medical records of the patients were used as source of data .
all the patients were subjected to a detailed clinical examination and bacteriological examination with slit - skin smears .
investigations like nerve biopsy , electromyography , and nerve conduction studies were done in patients with diagnostic difficulties.results:patients presented with neurological symptoms like paresthesias ( 60% ) , diminished sensations ( 40% ) , nonhealing ulcers ( 30% ) , and blisters ( 20% ) .
all except one had thickened nerves on clinical examination .
slit - skin smear was negative in all but one patient .
nerve biopsy confirmed the diagnosis of leprosy in seven cases.conclusion:pure neural leprosy is difficult to diagnose with routine methods .
the diagnosis should be considered , especially by neurologists and dermatologists , who are more likely to see such patients with predominant neural manifestations .
the diagnosis should be confirmed with nerve biopsy to prevent delay in therapy and associated complications . |
dna microarray experiments have huge potential for screening for gene expression of relevance in particular contexts . however , the output of such an experiment is often just a list of ' fold - changes ' in gene - expression levels and so researchers face the question of whether their ' hits ' can be trusted or not . in the absence of any knowledge of what to expect ,
most researchers simply draw a line at a given fold - change and examine whatever is above it .
the largest fold - changes in highly expressed genes can usually be trusted . however , because the ' correct ' fold - change limit typically shifts with decreasing intensity of expression , a fixed fold - change line is inadequate in the range of expression levels where most genes actually lie .
most papers reporting microarray experiments cut off their candidate lists in essentially arbitrary ways , at the level that the researchers feel comfortable with , rather than on the basis of statistics . here
we present an easy but sound recipe for quantifying statistical significance , based on careful statistical characterization of a large dataset of genechip experiments .
a particular feature of genechip arrays is that each transcript is probed by many short snippets of sequence , instead of a single longer probe as in cdna arrays .
therefore , translating the measured probe intensities into a global gene - intensity or ratio score requires a composite scoring function . in principle
, the redundancy in the probes offers a way to reduce the noise level for each gene ; on the other hand , finding the best estimator is difficult and it is likely that the variability in probe behavior will prevent a single estimator from being optimal in all cases . studying the raw data
reveals its great complexity , and the hybridization processes underlying the measured perfect - match ( pm ) versus single - mismatch ( mm ) intensities prove hard to interpret physically .
the principal difficulties stem first from the large number of probes with mm intensities higher than the corresponding pm , and therefore not conforming to the usual hybridization picture ; and second , from the very broad intensity distributions within each probe set .
the first task is therefore to design a method that can robustly handle such input data .
second , once reliable measures for differential expression from two experiments are obtained , one would like to measure their significance level .
it is now widely accepted that such measures should be derived in an intensity - dependent fashion .
there are at least two independent sources of variability to be considered : first , the intrinsic noise levels related to the technology ( type i noise ) , which includes noise components introduced by the enzymatic step used in the crna preparation ( see materials and methods ) and the fluorescence measurement ( scan ) ; and second , the variability encountered in biological replicates .
previous studies have addressed significance issues in both cdna and genechip arrays : they have discussed significance according to intrinsic noise levels ; or focused on variability in replicates only ; or considered both simultaneously .
high - density oligonucleotide microarrays ( hdonas ) are composed of 25-base oligonucleotide probes synthesized and attached to a glass matrix by photolithographic techniques .
as such a short oligonucleotide sequence would not give sufficiently specific hybridization alone , genechip uses 14 - 20 different oligonucleotides to probe each transcript ; and each comes in two versions - the pm probe and the mm probe . in the latter
, the central base has been substituted by its complement and this probe is intended to control for nonspecificity .
the pairs ( pm , mm ) are called probe pairs and the full set of probes for a given gene is called a probe set .
the standard picture used to interpret the hybridization is based on the following model : mm = ( 1 - ) is + ' ins + b where pm ( mm ) is the observed brightness , is the contribution from specific complementary binding , ins the amount from nonspecific binding , and b a background of physical origin , that is , the photodetector dark current or light reflections from the scanning process . the proper technique for estimating the background and its fluctuations is discussed in .
then , ( thought to be positive ) reflects the loss of binding due to a single substitution , and , ' are the susceptibilities for nonspecific binding .
in the ideal case , which is usually assumed , = ' and therefore the subtraction pm - mm = ( 1 - ) is is directly proportional to the desired signal .
we shall focus on the following two aspects of genechip data analysis : first , we describe a method to evaluate ratio scores and associated quality measures . in this step
, we shall relax the assumption that = ' and consider either the pm probes only or the usual pm - mm subtraction .
these cases were chosen to bracket the extremes of an ideally performing mm probe and a poor mm .
second , we use the assigned ratio scores and show how one can , with moderate effort , attribute a significance level to differentially expressed genes .
our approach is somewhat similar to that described in , in the sense that it relies on an empirical characterization of the noise envelope , and is more distantly related to that described in .
both these approaches were developed and applied in the context of cdna arrays ( see materials and methods for a discussion of the difference between our method and ) .
there are two types of approaches to composite scores : first , the ' direct ' methods aim at obtaining scores based on the distribution study of the probe intensities and can be applied to a single experiment ( or pair in the case of ratio estimators ) ; the second approach is model based and attempts to fit the susceptibilities and from a collection of arrays .
a major difference in the two methods is that the number of experiments needed can be just one ( or two for ratios ) in the first case , whereas a large number of arrays of similar quality ( ideally as many as the number of probe pairs for the reduced model ) are required for the second .
model - based approaches seem to be well suited for absolute intensity measurements ; on the other hand , direct methods are not expected to be very robust for absolute intensities , because of the broad intensity distributions within probe sets . however , the situation is different when considering ratio scores , as the variability in the individual probe susceptibilities cancels out when considering the expression ratios at the probe level .
ratio scores should therefore be expected to be more robust ; more precisely , when comparing two conditions , we consider each probe ratio to provide an independent measurement of the real expression ratio - independent in the sense that the 16 ratios provide independent samples from a distribution whose location we want to estimate .
our composite ratio estimation is based on a standard least trimmed square ( lts ) estimator of the set of log - ratios for each probe set ( see materials and methods for details ) .
we consider the cases for which the probe log - ratios ( lr ) are derived either from the usual pm - mm subtracted intensities , or from the pm values alone ( after background subtraction ) .
the rationale behind proposing a variant without the subtraction lies in the empirical observation that in 30% of the total probe pairs mm binds better than pm .
this is true for all chip series tested ( mouse , human , drosophila ) , except for yeast , which happens to be significantly better ( 15% ) . in such probe pairs
, targets systematically bind more strongly to the mm , hence violating the prediction from the above model .
importantly , these ' misbehaving ' pairs are not just restricted to a few noisy probe sets , but are fairly homogeneously distributed among the probe sets , occurring also in sets with overall high intensities .
figures 1 and 2 show the general trends in the relations between the ratio measurements and their quality measures , for both the pm and pm - mm cases .
we look at a collection of 12 mu11ksuba chips hybridized to mrna extracts from different mouse brain regions ( see materials and methods ) .
for the purpose of the present discussion , we believe the trends are well captured by the set of ratios shown ; we picked this dataset because , compared with other datasets we studied , the ratios span a relatively large dynamic range .
the main observation is that the three quantities : the log - ratio ( lr ) , the standard error ( se ) , and the wilcoxon rank sign test p - value show little correlation with each other , and therefore represent relatively ' independent ' indicators ( see materials and methods for the precise definitions ) .
the lines indicating a signal - to - noise ratio of 1 clearly show that the vast majority of the measurements are well defined , especially for the larger log - ratios . the behavior of se when the number of probes ( ngood ) retained for deriving the ratio score is small ( as indicated by the colored dots )
is well understood in terms of the number of residuals considered in the lts method , that is , genes with ngood = 1 necessarily have se = 0 .
the only obvious correlation is that small p - values are not compatible with lr = 0 , as shown by the valley along lr = 0 in the contour plots of lr versus p. it is , however , possible to achieve very small p - values for tiny fold - changes , as small as 1.1 .
the pm and pm - mm methods show very similar features overall , the biggest difference being that p - values tend to be larger for large lrs in the pm - mm , which reflects the overall smaller number of ngood probes usable in that method ( there are more probes lying below background after the subtraction ) .
the difference in the log - ratios from the pm and pm - mm methods is illustrated in figure 3 .
although there is a branch with lr ~ 0 from the pm method when all p - values are considered , this branch rapidly disappears when focusing at smaller p - values only .
cases where the pm and pm - mm scores indicate regulation in opposite directions are virtually absent when p < 0.05 .
however , one can see a ' compression effect ' in the scores from the pm method , shown by the edges with slope > 1 near the regions indicated by the arrows in the bottom right panel ( this can also be seen by comparing the upper two contour plots of figures 1 and 2 ) .
this compression probably reflects cross - hybridization effects that are not corrected for in the pm - only method .
however , if one is more interested in finding significant changes than in the lr values themselves , the determining quantity is the lr value divided by the width of the local noise .
therefore , compression in the scale is not dramatic as long as the noise envelope also shrinks ( see discussion ) .
a comparison of the lr / se ( signal - to - noise ratio , sn ) from both methods emphasizes the complementarity of both methods ( figure 4 ) , as there is clearly a similar fraction of genes that have poor sn ratios ( sn < 2 ) in one case but acceptable ratios in the other .
these are found in the top - left and bottom - right quadrants defined by the horizontal and vertical blue lines .
we have shown previously using the same mu11k dataset that our pm - only composite ratios lead to a reduction in variance , especially at low intensities , when compared to the microarray analysis suite 3.2 available at that time . in figure 5
we show typical scatterplots with increasing levels of overall differential regulation , from duplicates to strong regulation ( going from left to right ) .
although these particular data are from a subset of the mu11ksuba chips used for figures 1 and 2 , our experience is that these are very typical of genechip hybridization data from numerous chip series . we shall always refer to duplicates as ' experiments ' where the enzymatic steps ( see protocols in materials and methods ) in the target sample preparations have been performed independently . in ideal terms
, the scatter cloud is thought of as consisting of two components : one is just noise from the enzymatic and hybridization steps affecting all the genes ; the other reflects true sample differences . to illustrate this , we give three prototypical cases showing the data for the individual genes and the local variance regression lines ( figure 5 ) . in these ,
the second component increases gradually from zero ( left - most plot , duplicates ) , as visible in the quantile - quantile ( qq ) plots in figure 5b .
the nearly straight left - most qq plot indicates that variable lr/ ( ) closely follows a normal distribution . as the amount of true regulation increases , longer tails develop that depart from normal behavior .
the fact that the noise component behaves as local log - normal distributions is not dictated by the choice of the variable lr/ ( ) , on the contrary , it emerges as a rather pleasant feature of genechip experiments . in figure 6
, we demonstrate that this log - normality occurs very systematically : we show the two best and two worst ( judged by the linearity of the qq plots and the amount of outliers ) from 40 human hg - u95a duplicates collected in a study of rheumatoid arthritis ( see materials and methods ) .
the majority of the cases look closer to the first two examples ; and the pm and pm - mm methods lead to equally good log - normal distributions overall .
the mean and variation in the local sd for both the pm and pm - mm methods are shown in figure 7 and reflect the characteristic contraction of the noise envelope with increasing coordinates along the diagonal .
it is obvious that the pm noise envelope is thinner than that of the pm - mm at low intensity ; on the other hand , both methods lead to comparable local in the ' flat ' mid to high - intensity domains , where over half of the data lies .
there , is approximately 0.15 , so that 2 corresponds to a ratio of 2 = 1.25 , so 95% of repeated measurements would fall within a factor of 1.25 of their mean . barring some artifact affecting large numbers of probes simultaneously , we would expect then that approximately 95% of the measurements in the mid- to high - intensity range are reproducible within a factor of around 1.25 .
figures 1 and 2 show the general trends in the relations between the ratio measurements and their quality measures , for both the pm and pm - mm cases .
we look at a collection of 12 mu11ksuba chips hybridized to mrna extracts from different mouse brain regions ( see materials and methods ) .
for the purpose of the present discussion , we believe the trends are well captured by the set of ratios shown ; we picked this dataset because , compared with other datasets we studied , the ratios span a relatively large dynamic range .
the main observation is that the three quantities : the log - ratio ( lr ) , the standard error ( se ) , and the wilcoxon rank sign test p - value show little correlation with each other , and therefore represent relatively ' independent ' indicators ( see materials and methods for the precise definitions ) .
the lines indicating a signal - to - noise ratio of 1 clearly show that the vast majority of the measurements are well defined , especially for the larger log - ratios .
the behavior of se when the number of probes ( ngood ) retained for deriving the ratio score is small ( as indicated by the colored dots ) is well understood in terms of the number of residuals considered in the lts method , that is , genes with ngood = 1 necessarily have se = 0 .
the only obvious correlation is that small p - values are not compatible with lr = 0 , as shown by the valley along lr = 0 in the contour plots of lr versus p. it is , however , possible to achieve very small p - values for tiny fold - changes , as small as 1.1 .
the pm and pm - mm methods show very similar features overall , the biggest difference being that p - values tend to be larger for large lrs in the pm - mm , which reflects the overall smaller number of ngood probes usable in that method ( there are more probes lying below background after the subtraction ) .
the difference in the log - ratios from the pm and pm - mm methods is illustrated in figure 3 .
although there is a branch with lr ~ 0 from the pm method when all p - values are considered , this branch rapidly disappears when focusing at smaller p - values only .
cases where the pm and pm - mm scores indicate regulation in opposite directions are virtually absent when p < 0.05 .
however , one can see a ' compression effect ' in the scores from the pm method , shown by the edges with slope > 1 near the regions indicated by the arrows in the bottom right panel ( this can also be seen by comparing the upper two contour plots of figures 1 and 2 ) .
this compression probably reflects cross - hybridization effects that are not corrected for in the pm - only method .
however , if one is more interested in finding significant changes than in the lr values themselves , the determining quantity is the lr value divided by the width of the local noise .
therefore , compression in the scale is not dramatic as long as the noise envelope also shrinks ( see discussion ) .
a comparison of the lr / se ( signal - to - noise ratio , sn ) from both methods emphasizes the complementarity of both methods ( figure 4 ) , as there is clearly a similar fraction of genes that have poor sn ratios ( sn < 2 ) in one case but acceptable ratios in the other .
these are found in the top - left and bottom - right quadrants defined by the horizontal and vertical blue lines .
we have shown previously using the same mu11k dataset that our pm - only composite ratios lead to a reduction in variance , especially at low intensities , when compared to the microarray analysis suite 3.2 available at that time .
in figure 5 we show typical scatterplots with increasing levels of overall differential regulation , from duplicates to strong regulation ( going from left to right ) .
although these particular data are from a subset of the mu11ksuba chips used for figures 1 and 2 , our experience is that these are very typical of genechip hybridization data from numerous chip series .
we shall always refer to duplicates as ' experiments ' where the enzymatic steps ( see protocols in materials and methods ) in the target sample preparations have been performed independently . in ideal terms , the scatter cloud is thought of as consisting of two components : one is just noise from the enzymatic and hybridization steps affecting all the genes ; the other reflects true sample differences . to illustrate this , we give three prototypical cases showing the data for the individual genes and the local variance regression lines ( figure 5 ) . in these ,
the second component increases gradually from zero ( left - most plot , duplicates ) , as visible in the quantile - quantile ( qq ) plots in figure 5b .
the nearly straight left - most qq plot indicates that variable lr/ ( ) closely follows a normal distribution . as the amount of true regulation increases ,
the fact that the noise component behaves as local log - normal distributions is not dictated by the choice of the variable lr/ ( ) , on the contrary , it emerges as a rather pleasant feature of genechip experiments . in figure 6
, we demonstrate that this log - normality occurs very systematically : we show the two best and two worst ( judged by the linearity of the qq plots and the amount of outliers ) from 40 human hg - u95a duplicates collected in a study of rheumatoid arthritis ( see materials and methods ) .
the majority of the cases look closer to the first two examples ; and the pm and pm - mm methods lead to equally good log - normal distributions overall .
the mean and variation in the local sd for both the pm and pm - mm methods are shown in figure 7 and reflect the characteristic contraction of the noise envelope with increasing coordinates along the diagonal .
it is obvious that the pm noise envelope is thinner than that of the pm - mm at low intensity ; on the other hand , both methods lead to comparable local in the ' flat ' mid to high - intensity domains , where over half of the data lies .
there , is approximately 0.15 , so that 2 corresponds to a ratio of 2 = 1.25 , so 95% of repeated measurements would fall within a factor of 1.25 of their mean .
barring some artifact affecting large numbers of probes simultaneously , we would expect then that approximately 95% of the measurements in the mid- to high - intensity range are reproducible within a factor of around 1.25 .
our experience is that despite constant improvements , current incarnations of the arrays still behave fairly inhomogeneously as far as their pm and mm hybridization properties are concerned .
this is probably the consequence of various sequence - dependent effects : first , the difference in stacking energies of single - stranded snippets between the pm and the mm sequences can easily be in the range of the gain in binding energies ; second , there are certainly kinetic effects as the hybridizations are not carried to complete equilibrium ; and third , there is always the possibility of sequence - dependent synthesis efficiencies .
the wide range of probe set behavior is best seen in the sn ratios in figure 4 . for these reasons
, we believe that a safe way to proceed is to integrate the results from both pm - only and pm - mm methods .
for instance , considering the intersection ( or union ) of genes predicted by either method would minimize the false - positive ( or false - negative ) rates .
in addition , there seems to be a significant variation in the hybridization properties across different chip series , as can be observed from simple statistics on the number of probe pairs with mm hybridizing better than pm ( see results ) .
the superiority of the yeast chip mentioned above may of course be related to the relative simplicity of the yeast genome compared to that of the higher organisms .
another point worth mentioning is that the values of the ratio scores may deviate from the real mrna concentration ratios in some intensity regimes as the result of various effects such as non - linearities in the probes ' binding affinities .
this emphasizes the main point of our work , namely the importance of measuring differential expression relative to the local noise ; only then can we decide whether a given ratio score can be considered as indicating true regulation or not .
finally , the question of handling significance across replicated experiments is a second step to be built on top of the analysis presented above .
the most reasonable approach would be to follow , namely to consider the t - statistics of the expression ratios across the samples .
however , one would also want to weight the average according to the noise content in each of the samples , in a manner similar to that discussed in .
we briefly describe here the two datasets presented , and what we refer to in the text as the ' enzymatic steps ' .
all six brain regions were obtained from adult ( 2 - 3-month - old ) cd-1 mice .
dissections were carried out in ice - cold buffer , and tissues were immediately frozen with liquid nitrogen .
poly ( a ) rna was then isolated with magnetic oligo - dt beads . for each brain region ,
labeled crnas were produced from the double - stranded cdna libraries and hybridized to chips according to the affymetrix protocol , including the antibody - amplification step .
the same protocol was used , except that no poly(a ) isolation was done before the conversion to cdna . to compute expression ratios for genes measured in two separate arrays , let ( xi , yi ) denote the brightness measurements for one probe set ( the index i ranges from 1 to the number of probe pairs for the particular probe set , 14 - 20 depending on the chip series ) taken in the two different hybridization arrays x and y. we investigate both cases in which the intensities ( xi , yi ) are either the intensities of the background - subtracted pm cells or the pm - mm values ( which need no background correction ) .
only ngood ' good ' probe pairs are retained for determining the ratio and associated quantities . we discard probes that are saturated in both x and y , or probe pairs such that pm - mm < 3 or pm < 3 in both x or y. here , corresponds to the standard deviation of the fluctuations in the background intensity .
not considering such probes prevents contamination of the ratio estimates from noisy low - intensity probes . after identifying the probe pairs allowed into the analysis , the differential expression score lr for the gene in question
is obtained from a lts robust regression of lri = log2(xi / yi ) to an intercept = lr .
we used the default ns = ( ngood/2 ) + 1 and this parameter can be adjusted in our scripts ; however , we found no evidence for changing the default .
an estimate of the standard error ( se ) for is given by se = .
composite absolute intensities for the gene in each experiment can be obtained via geometric means of the ( xi , yi ) probes kept in the lts regression , however , these are only indicative measures as the method was designed primarily for expression ratios .
in addition to the se , which reports a quantitative estimate of the error in the log - ratio measurement , it is also instructive to report a p - value from a paired wilcoxon rank sign test of the lri values . casually speaking , this value is related to the portion of the probes indicating gene regulation in the same direction : the theoretical minimum p - value , pmin , is achieved when all probe ratios agree on the same direction of regulation . moreover , the test is non - parametric as it is operating in rank space , and p therefore also incorporates information about the number of probe pairs used ( ngood ) .
namely , the wilcoxon p - value has a lower bound that decreases with increasing sample size . for instance pmin = 1/4 for ngood = 3 and 1/8 for ngood
= 4 , so that small p scores can only be reached when enough probes are used . however , the converse is not true , as a gene that is not differentially expressed can have a p - value that is close to 1 even if all the probe pairs are ' good ' in the above sense .
our method does not primarily aim at quantifying the presence or absence of a gene in a particular sample .
nevertheless , we report the number of probes ( nabove ) with intensity larger than 3eff ( eff = for the pm - mm case ) for both samples x and y. using enough data , one could compute a probability of presence depending on nabove , and it is likely that this calibration would be dependent on the chip series .
the measures described above are all single - gene properties ; they can be computed when given just the intensities gathered for a single gene . in contrast , correcting for systematic trends ( also called ' data massage ' ) and more important , classifying expression ratios according to their significance , requires measures that involve the entire gene population on the arrays .
we stress that these techniques are meaningful only when the number of genes probed is sufficiently large , and under the assumption that a large fraction of them does not show differential regulation between the two tested samples .
normalization aims at correcting for systematic trends ( that is , bias as a result of dye efficiencies and amplification , sample concentration , photodetector efficiency ) so as to make a collection of arrays directly comparable . one must distinguish global from local normalization : in the first , the intensities of all the probes on the array are scaled by a constant factor ; in the second , the normalization factor can be intensity dependent .
local normalization techniques are mostly discussed in the context of cdna arrays , where the intensity dependence can be severe .
hdonas suffer less from ' bent ' noise structures ; nevertheless , local normalization has also been introduced for them .
although attractive , local normalization should not be applied blindly as it can hide real failures in the data and create its own artifacts .
our approach to normalization is based on centering the log - ratio distribution either globally , or locally as in . for the data presented in the results section , local normalization was used ; however , our scripts allow a choice between the local and global schemes ( see additional data files for scripts ) .
we always normalize an array with respect to another one , and we found it more accurate to do so at the gene rather than the probe level ( we normalize the composite ratio scores a posteriori instead of normalizing the raw probe intensities ) . turning to the noise structure , significance of regulation is quantified from a local robust regression ( ) of the variable lr versus 77 , where lr = log(ix / iy ) is the log - ratio of the intensities and = log(ixiy)/2 is half the log - product .
ix and iy denote the locally normalized intensities of the genes in channels x and y. we should emphasize that estimating the local variance in this manner only makes sense after the arrays have been locally normalized .
the function ( ) then quantifies the local log - ratio variance , so that the local sd is given by ( ) = . we used the r routine loess for the fitting .
the justification for using the local sd as a criterion for significance relies upon the empirical fact that the variable lr/ ( ) follows a good normal distribution in the case of replicate ( pure noise ) experiments ( see figure 6 ) .
the significance of a ratio score can therefore be assessed using the value lr / sd ; that is , a value lr / sd = 2 implies that the null hypothesis that the gene is not regulated can be rejected with a 95% confidence level . we finally comment on the precise differences between our approach and that in .
first , we found no evidence for the inclusion of an additive term in linear coordinates .
judging by the data , the noise structure is very well captured by an effective multiplicative model ( see results ) .
second , the multiplicative noise component is estimated in logarithmic coordinates instead of linear , and after a local normalization .
finally , we estimate the local scale in the noise by an empirical robust fit of the local variance , with no a priori model .
while it would be satisfactory to have a physical model describing the noise , our experience is that it is very hard to formulate one that accounts for the observed structure in all cases .
we briefly describe here the two datasets presented , and what we refer to in the text as the ' enzymatic steps ' .
all six brain regions were obtained from adult ( 2 - 3-month - old ) cd-1 mice .
dissections were carried out in ice - cold buffer , and tissues were immediately frozen with liquid nitrogen .
poly ( a ) rna was then isolated with magnetic oligo - dt beads . for each brain region ,
labeled crnas were produced from the double - stranded cdna libraries and hybridized to chips according to the affymetrix protocol , including the antibody - amplification step .
the same protocol was used , except that no poly(a ) isolation was done before the conversion to cdna .
all six brain regions were obtained from adult ( 2 - 3-month - old ) cd-1 mice .
dissections were carried out in ice - cold buffer , and tissues were immediately frozen with liquid nitrogen .
poly ( a ) rna was then isolated with magnetic oligo - dt beads . for each brain region , 1 g poly(a ) rna was converted to double - stranded t7 cdna . labeled crnas were produced from the double - stranded cdna libraries and hybridized to chips according to the affymetrix protocol , including the antibody - amplification step .
the same protocol was used , except that no poly(a ) isolation was done before the conversion to cdna .
to compute expression ratios for genes measured in two separate arrays , let ( xi , yi ) denote the brightness measurements for one probe set ( the index i ranges from 1 to the number of probe pairs for the particular probe set , 14 - 20 depending on the chip series ) taken in the two different hybridization arrays x and y. we investigate both cases in which the intensities ( xi , yi ) are either the intensities of the background - subtracted pm cells or the pm - mm values ( which need no background correction ) . only ngood '
we discard probes that are saturated in both x and y , or probe pairs such that pm - mm < 3 or pm < 3 in both x or y. here , corresponds to the standard deviation of the fluctuations in the background intensity .
not considering such probes prevents contamination of the ratio estimates from noisy low - intensity probes . after identifying the probe pairs allowed into the analysis , the differential expression score lr for the gene in question
is obtained from a lts robust regression of lri = log2(xi / yi ) to an intercept = lr .
we used the default ns = ( ngood/2 ) + 1 and this parameter can be adjusted in our scripts ; however , we found no evidence for changing the default .
an estimate of the standard error ( se ) for is given by se = .
composite absolute intensities for the gene in each experiment can be obtained via geometric means of the ( xi , yi ) probes kept in the lts regression , however , these are only indicative measures as the method was designed primarily for expression ratios .
in addition to the se , which reports a quantitative estimate of the error in the log - ratio measurement , it is also instructive to report a p - value from a paired wilcoxon rank sign test of the lri values . casually speaking , this value is related to the portion of the probes indicating gene regulation in the same direction : the theoretical minimum p - value , pmin , is achieved when all probe ratios agree on the same direction of regulation . moreover , the test is non - parametric as it is operating in rank space , and p therefore also incorporates information about the number of probe pairs used ( ngood ) .
namely , the wilcoxon p - value has a lower bound that decreases with increasing sample size .
for instance pmin = 1/4 for ngood = 3 and 1/8 for ngood = 4 , so that small p scores can only be reached when enough probes are used .
however , the converse is not true , as a gene that is not differentially expressed can have a p - value that is close to 1 even if all the probe pairs are ' good ' in the above sense .
our method does not primarily aim at quantifying the presence or absence of a gene in a particular sample .
nevertheless , we report the number of probes ( nabove ) with intensity larger than 3eff ( eff = for the pm - mm case ) for both samples x and y. using enough data , one could compute a probability of presence depending on nabove , and it is likely that this calibration would be dependent on the chip series .
the measures described above are all single - gene properties ; they can be computed when given just the intensities gathered for a single gene . in contrast , correcting for systematic trends ( also called ' data massage ' ) and more important , classifying expression ratios according to their significance , requires measures that involve the entire gene population on the arrays .
we stress that these techniques are meaningful only when the number of genes probed is sufficiently large , and under the assumption that a large fraction of them does not show differential regulation between the two tested samples .
normalization aims at correcting for systematic trends ( that is , bias as a result of dye efficiencies and amplification , sample concentration , photodetector efficiency ) so as to make a collection of arrays directly comparable . one must distinguish global from local normalization : in the first , the intensities of all the probes on the array are scaled by a constant factor ; in the second , the normalization factor can be intensity dependent .
local normalization techniques are mostly discussed in the context of cdna arrays , where the intensity dependence can be severe .
hdonas suffer less from ' bent ' noise structures ; nevertheless , local normalization has also been introduced for them .
although attractive , local normalization should not be applied blindly as it can hide real failures in the data and create its own artifacts .
our approach to normalization is based on centering the log - ratio distribution either globally , or locally as in . for the data presented in the results section
, local normalization was used ; however , our scripts allow a choice between the local and global schemes ( see additional data files for scripts ) .
we always normalize an array with respect to another one , and we found it more accurate to do so at the gene rather than the probe level ( we normalize the composite ratio scores a posteriori instead of normalizing the raw probe intensities ) . turning to the noise structure , significance of regulation is quantified from a local robust regression ( ) of the variable lr versus 77 , where lr = log(ix / iy ) is the log - ratio of the intensities and = log(ixiy)/2 is half the log - product .
ix and iy denote the locally normalized intensities of the genes in channels x and y. we should emphasize that estimating the local variance in this manner only makes sense after the arrays have been locally normalized .
the function ( ) then quantifies the local log - ratio variance , so that the local sd is given by ( ) = .
the justification for using the local sd as a criterion for significance relies upon the empirical fact that the variable lr/ ( ) follows a good normal distribution in the case of replicate ( pure noise ) experiments ( see figure 6 ) .
the significance of a ratio score can therefore be assessed using the value lr / sd ; that is , a value lr / sd = 2 implies that the null hypothesis that the gene is not regulated can be rejected with a 95% confidence level .
first , we found no evidence for the inclusion of an additive term in linear coordinates .
judging by the data , the noise structure is very well captured by an effective multiplicative model ( see results ) .
second , the multiplicative noise component is estimated in logarithmic coordinates instead of linear , and after a local normalization .
finally , we estimate the local scale in the noise by an empirical robust fit of the local variance , with no a priori model .
while it would be satisfactory to have a physical model describing the noise , our experience is that it is very hard to formulate one that accounts for the observed structure in all cases .
scripts for converting between file types are available with this article ( cdf2psc , cel2ratios , cel2raw , raw2pcel ; see explanatory file for more details ) and at the authors ' website .
click here for additional data file cel2ratios : converts two .pcel files into ratios . click here for additional data
f.n . is a bristol - meyers squibb fellow in basic neurosciences and acknowledges support from the swiss national science foundation . m.m . acknowledges support from the meyer foundation
relationships between the lr , se and p measures for the pm - only scores .
the right panels show contour plots of the densities raised to the power 0.2 , so as to resolve structure in the low - density regions ; the ranges of the right - hand panels were chosen to emphasize the most interesting features of the densities .
the red , green , blue , cyan and magenta dots refer to n = 1 , 2 , 3 , 4 , 5 ' good ' cell pairs , respectively .
the yellow line in the top - left panel represents |lr| = se , so that points below the line have signal - to - noise ratios > 1 .
the se for the red dots ( n = 1 ) is artificially set to 0.001 for plotting purposes ; it should strictly be 0 .
relationships between the lr , se and p measures for the pm - mm method . description and colors as for figure 1 .
comparison between the ratio scores from the pm - only and the pm - mm methods . only genes with p - values ( from the pm - mm method ) smaller than indicated are plotted .
the brightest red dots have the smallest p - values ( around 10 ) , whereas black dots correspond to p = 1 ( upper left panel ) to p = 0.01 ( lower right panel ) .
comparison of the signal - to - noise ratios ( sn ) for the pm and pm - mm methods . only genes with ngood > 4 in the pm - mm method are plotted .
the red lines are contour lines and the blue lines denote the diagonal and sn values of 2 on either axis .
( a ) typical scatterplot showing increasing levels of differential regulation , together with the 2 noise envelopes ( red lines ) .
there are three different conditions : a , b and c. aa is a duplicate of a. ( b ) associated qq plots of lr/ ( ) .
the data shown here were obtained using four out of the 12 mu11ksuba chips used in figures 1 and 2 .
qq plots of lr ( ) versus normal distributions in replicate hg - u95a experiments .
sd of the log2-ratios from 40 pairs of replicate hg - u95a experiments are in black .
the intensity i = ( ixiy ) measures the coordinate along the diagonal of the scatterplots , and the red lines represent the density of the variable i in arbitrary units ( but the same in both panels ) .
note that the mode of the pm - mm lies lower than that of the pm line . | backgroundhigh - density oligonucleotide arrays ( hdonas ) are a powerful tool for assessing differential mrna expression levels . to establish the statistical significance of an observed change in expression
, one must take into account the noise introduced by the enzymatic and hybridization steps , called type i noise .
we undertake an empirical characterization of the experimental repeatability of results by carrying out statistical analysis of a large number of duplicate hdona experiments.resultswe assign scoring functions for expression ratios and associated quality measures .
both the perfect - match ( pm ) probes and the differentials between pm and single - mismatch ( mm ) probes are considered as raw intensities .
we then calculate the log - ratio of the noise structure using robust estimates of their intensity - dependent variance .
the noise structure in the log - ratios follows a local log - normal distribution in both the pm and pm - mm cases .
significance relative to the type i noise can therefore be quantified reliably using the local standard deviation ( sd ) .
we discuss the intensity dependence of the sd and show that ratio scores greater than 1.25 are significant in the mid- to high - intensity range.conclusionsthe noise inherent in hdonas is characteristically dependent on intensity and can be well described in terms of local normalization of log - ratio distributions .
therefore , robust estimates of the local sd of these distributions provide a simple and powerful way to assess significance ( relative to type i noise ) in differential gene expression , and will be helpful in practice for improving the reliability of predictions from hybridization experiments . |
single fiber emg ( sfemg ) is a powerful technique to study the pathophysiology of the motor unit .
two types of measurements are made using this technique : fiber density ( fd ) and jitter .
the fd is useful to study the grouping of muscle fibers of a motor unit within its territory . in neuropathy , fd increases due to reinnervation .
, the fd may be increased slightly due to fiber splitting , regeneration of muscle fibers , etc .
the jitter is usually normal . in this manner , sfemg is not particularly useful in the diagnosis of myopathy . it is often used to rule out other diseases such as a neuropathy or a neuromuscular junction disease .
the abnormalities of muscle fiber diameter are observed indirectly on electrodiagnostic studies . on routine needle emg examination , increased variability gives motor unit potentials with polyphasic waveforms .
atrophy can give low amplitude ( in what follows by amplitude we mean the peak - to - peak value of potential change , counted in mv ) potentials [ 1 , 8 , 9 ] . the variability of muscle fiber diameter may be studied indirectly by investigating the muscle fiber conduction velocity .
the muscle fibers are stimulated directly using an intramuscular needle , and their action potentials are recorded at a few millimeter distance .
, the shape of the single muscle fiber action potential also contains information about the muscle fiber diameter . in the so - called line source mode , the extracellular muscle fiber action potential v(t ) is computed as : 1\documentclass[12pt]{minimal }
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\begin{document}$$ v\left ( t \right ) = \mathop \int \nolimits \left ( { \varphi \left ( { t - \tau } \right)i\left ( \tau \right)d\tau}\right ) $ $ \end{document}where i(t ) is the transmembrane current and is a weight function .
hence , amplitude alone can not be used as a marker of the fiber diameter .
the weight function is the potential recorded by the electrode as a unit current source propagates from the endplate to the tendon .
the waveform of this function is thus dependent on the propagation velocity of muscle fiber , and hence the fiber diameter .
the change in weight function waveform with radial distance and with fiber diameter has not been investigated systematically . in this study , we have used computer simulation to study the relationship between the muscle fiber diameter and parameters of potential : peak - to - peak amplitude and duration of the negative peak of sfp .
these relationships are used to develop a graphical and an analytical tool to estimate the muscle fiber diameter from the recorded action potential .
although our goal is similar , our method of analysis is quite different from that used by rodriguez et al .
we believe that the graphical method described in this study offers more simplicity and gives a better understanding of the action potential waveform .
the line source model described by nandedkar and stlberg was used for simulating single muscle fiber action potentials .
this model has been tested in simulations of normal and abnormal emg signals , and shows a good concordance with experimental and clinical recordings [ 4 , 5 ] .
the single fiber potential v recorded at the electrode at time t , coming from a single fiber , is given by a convolution of a weight function (t ) and current i(t ) given by ( 1 ) .
the effect on the potential v of the distance of the electrode from the fiber is described by the weight function , which is defined as follows : 2\documentclass[12pt]{minimal }
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\begin{document}$$ \varphi \left ( { r , z } \right ) = \frac{1}{{4\pi \sigma_{r } } } \frac{1}{{\sqrt { kr^{2 } + z^{2 } } } } $ $ \end{document}where r is the radial conductance and k depends on the ratio of axial to radial conductance , r and z are the radial and axial distance of electrode from the current source .
the axial distance z is related to time t by the speed of propagation of the potential along the fiber : z = vt , where the velocity of propagation v is linearly dependent on fiber diameter .
the action potentials were simulated for various combinations of muscle fiber diameter ( 2590 m ) and radial distance ( 50500 m ) .
the range of fiber diameters corresponds to the data from muscle biopsy . in normal muscle
the mean value is 50 5 m and in various neuromuscular disorders it is in range from 25 to 90 m .
the range of radial distances was determined so that the largest fibers would not be closer to the electrode than their radius ( 50 m ) .
the electrode records mainly from muscle fibers that are within 400 m of the recording surface .
the velocity of propagation of the current is determined by the diameter of the fiber according to the following formula : \documentclass[12pt]{minimal }
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\begin{document}$$ v = 2.2 + 0.05(d - 25 ) $ $ \end{document } , where the fiber diameter d is in m and the propagation velocity is in ms . for the simulation we have used our own software which is based on the formulation of the simulation method presented by nandedkar and stlberg . in this method
the potential is a result of the convolution of the weight function and source current given by ( 1 ) with the source current described by the formula derived by nandedkar and stlberg . using our software we are able to model the potential from one or more fibers and determine its parameters . in the modeling
we have assumed the same parameters for conductance as well as for the source current model as given in .
the model has been used by us to examine the properties of sfp in various neuromuscular disorders ( nandedkar et al . ) .
the amplitude was measured from maximum positive to maximum negative peaks ( fig . 1 ) .
the time difference between them is the duration of the negative peak ( fig .
the amplitude was measured from the maximum positive ( a ) to maximum negative peak ( b ) .
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\begin{document}$$ t_{z } $ $ \end{document } definitions of the sfp parameters .
the amplitude was measured from the maximum positive ( a ) to maximum negative peak ( b ) .
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\begin{document}$$ t_{z } $ $ \end{document } the change in the amplitude and duration with radial distance and muscle fiber diameter was investigated . in the experimental recordings ,
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\begin{document}$$ d = d(a,\;t_{z } ) $ $ \end{document}and4\documentclass[12pt]{minimal }
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\begin{document}$$ r = r\left ( { a,\;t_{z } } \right ) $ $ \end{document}by fixing tz , we obtain parametric curve with coordinates:5\documentclass[12pt]{minimal }
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\begin{document}$$ ( d , r)|_{{t_{z } } } = ( d(a ) , r(a ) ) $ $ \end{document}where the symbol \documentclass[12pt]{minimal }
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\begin{document}$$ ( d , r)|_{a } = ( d(t_{z } ) , r(t_{z } ) ) $ $ \end{document}we have approximated the dependencies between d , r , a , and tz as follows : the negative peak duration was approximated by the following two bi - quadratic polynomials:7\documentclass[12pt]{minimal }
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\begin{document}$$ c_{i , j , k } $ $ \end{document } are determined by fitting eqs .
( 7 ) and ( 8) is better suited to least squares bi - quadratic approximation than eqs .
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\begin{document}$$ c_{2,j , k } $ $ \end{document}1 , 19.5100e018.3844e011 , 22.2321e015.1557e011 , 32.0358e018.8151e022 , 17.3845e032.4920e032 , 23.4212e041.9468e042 , 31.6564e033.2125e043 , 12.5574e053.4911e063 , 23.3074e061.9169e063 , 36.4493e063.2255e07 the values of the coefficients \documentclass[12pt]{minimal }
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the results of simulation studies are shown in figs . 2 , 3 , 4 , 5 , and 6 . the dependence of the weight function on parameters is shown in fig . 2 .
the weight function is broader when the radial distance between the muscle fiber and the recording electrode is increased ( fig .
for the same distance , the smaller fibers have a broader weight function due to slower conduction velocity ( fig .
the simulated waveforms also show differences in the amplitude and durations . when their negative peaks are aligned and their amplitudes are normalized , larger fibers have a shorter negative peak duration ( fig .
the amplitude changes much more with radial distance than does the negative peak duration ( fig .
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\begin{document}$$ r $ $ \end{document } of needle from the fiber .
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\begin{document}$$ z = 0 $ $ \end{document}. b normalized weight function for muscle fibers of diameters : 30 and 80 m , located at a distance of 50 m from electrode .
3a sfp for fiber of diameter 30 and 90 m located at a distance of 100 m from the electrode .
potential due to larger fiber has been shifted in time ( by + 5.9 ms ) so that the maxima coincide .
the increase of the width of potential with the decrease of diameter is clearly seen .
b sfps for fibers with diameter of 30 , 45 , 60 , 75 , and 90 m located at a distance of 200 m from electrode .
it is seen how the amplitude of the sfp increases with the increase of fiber diameter and at the same time the potentials from larger fibers arrive earlier at the electrodefig .
4the negative peak duration ( \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } ) dotted line decreases with the increase in fiber diameter ( at fixed fiber to electrode distance ) .
the solid line is the dependence of amplitude on fiber diameter . with the increase of diameter
the amplitude is measured in mv , the negative peak duration is measured in msfig . 5the dependence of \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } ( dotted line ) and amplitude ( solid line ) on the electrode distance from the fiber for a fiber of diameter of 55 m and electrode located at distances from 50 to 300 m .
6the dependence of fiber diameter ( d ) on fiber to electrode distance ( r ) for a fixed amplitude ( a ) of the potential or a fixed duration \documentclass[12pt]{minimal }
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\begin{document}$$ ( t_{z } ) $ $ \end{document}. solid curves represent constant duration and dashed curves represent constant amplitude .
the values of amplitude are given along the top and right margins of the graph .
the values of constant duration are given in the lower part of the graph a the dependence of the normalized weighting function \documentclass[12pt]{minimal }
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\begin{document}$$ r $ $ \end{document } of needle from the fiber .
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\begin{document}$$ z = 0 $ $ \end{document}. b normalized weight function for muscle fibers of diameters : 30 and 80 m , located at a distance of 50 m from electrode .
the width of the weight function varies with the diameter of fiber a sfp for fiber of diameter 30 and 90 m located at a distance of 100 m from the electrode .
potential due to larger fiber has been shifted in time ( by + 5.9 ms ) so that the maxima coincide .
the increase of the width of potential with the decrease of diameter is clearly seen .
b sfps for fibers with diameter of 30 , 45 , 60 , 75 , and 90 m located at a distance of 200 m from electrode .
it is seen how the amplitude of the sfp increases with the increase of fiber diameter and at the same time the potentials from larger fibers arrive earlier at the electrode the negative peak duration ( \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } ) dotted line decreases with the increase in fiber diameter ( at fixed fiber to electrode distance ) .
the solid line is the dependence of amplitude on fiber diameter . with the increase of diameter
the amplitude is measured in mv , the negative peak duration is measured in ms the dependence of \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } ( dotted line ) and amplitude ( solid line ) on the electrode distance from the fiber for a fiber of diameter of 55 m and electrode located at distances from 50 to 300 m . the amplitude is measured in mv , the negative peak duration is measured in ms .
the amplitude decreases with distance and the negative peak duration increases the dependence of fiber diameter ( d ) on fiber to electrode distance ( r ) for a fixed amplitude ( a ) of the potential or a fixed duration \documentclass[12pt]{minimal }
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\begin{document}$$ ( t_{z } ) $ $ \end{document}. solid curves represent constant duration and dashed curves represent constant amplitude .
the values of amplitude are given along the top and right margins of the graph .
the values of constant duration are given in the lower part of the graph the amplitude and negative peak duration dependencies are shown on a single graph ( fig .
the solid curves represent the dependency of \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } values ( 0.41.4 ms ) and dashed curves represent the dependency of \documentclass[12pt]{minimal }
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\begin{document}$$ \left . {
( d , r ) } \right|_{a } $ $ \end{document } for a range of amplitude values ( 50 v5 mv ) . a plot of these dependencies ( fig .
6 ) allows one to estimate the fiber diameter and radial distance knowing the amplitude and negative peak duration .
for example , if a potential with amplitude of 0.7 mv and a negative peak duration of 0.6 ms is recorded , we could determine the distance and diameter from the intersection of the curve for constant amplitude = 0.7 mv ( solid line ) and constant duration = 0.6 ms ( dashed line ) .
the point of intersection gives the fiber diameter ( roughly 65 m ) and the radial distance ( 150 m ) .
while in principle the graphical tool , provided that the curves for constant amplitude or negative peak duration are dense enough , may be used to determine fiber diameter and distance from needle we have approximated the data with analytical formulae which makes them more suitable for use .
the graph , however , may be used to verify that the curves are smooth , nearly linear and that the two variables \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } give rise to two families of curves that are well separated ( fig .
6 ) . the graph may be readily used to compare the diameters for two or more sfps .
if two sfps have the same amplitude , so on the graph we are moving along one of the constant amplitude curves , then the one that has shorter negative peak duration is due to larger fiber .
this is because the negative peak duration depends on conduction velocity which in turn is proportional to fiber diameter .
hence the larger the fiber , the shorter the negative peak duration . in order to explain the dependence of fiber diameter on amplitude for a constant negative peak duration one has to note that the amplitude depends primarily on two factors
3b ) . for a constant \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } , the amplitude changes mainly due to the change in fiber to electrode distance .
the increase of radius , with the decreasing amplitude , leads to the broadening of the weight function . in order to keep the \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } constant the fiber diameter has to increase with the increase of radius .
hence for two sfps of the same negative peak duration the one for which the amplitude is smaller will be due to a larger fiber . in order to calculate the values of the coefficients \documentclass[12pt]{minimal }
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\begin{document}$$ c_{2,j , k } $ $ \end{document } we have simulated several hundreds of sfp with fiber diameter ranging from 25 to 90 m and radial distance ranging from 50 to 500 m calculating for each sfp its peak - to - peak amplitude and negative peak duration .
these data were then approximated using formulae ( 9 ) and ( 10 ) and the coefficients have been determined by standard linear least squares method .
the mean error of the determination of \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } from eq .
( 7 ) is \documentclass[12pt]{minimal }
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\begin{document}$$ 3 \times 10^ { - 3 } $ $ \end{document } therefore we have rounded the coefficients to 4 significant places . using this method to approximate the data it is found that the root mean square error of the determination of diameter is 2 m and for radial distance it is 6 m . the maximum error for \documentclass[12pt]{minimal }
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\begin{document}$$ d $ $ \end{document } is 8 m , and for \documentclass[12pt]{minimal }
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\begin{document}$$ r $ $ \end{document } it is 50 m .
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\begin{document}$$ d\;>125$$\end{document } m . hence the approximations given by eqs .
( 7 ) and ( 8) enable to determine \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } with satisfactory accuracy .
for example , using these equations for a simulated sfp with fiber diameter \documentclass[12pt]{minimal }
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\begin{document}$$ \pm 20$$\end{document } v for amplitude . for \documentclass[12pt]{minimal }
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\begin{document}$$ \pm 0.04\;{\text{ms } } $ $ \end{document } which corresponds to sampling frequency of 25 khz .
it is found that with the assumed value for the error in \documentclass[12pt]{minimal }
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\begin{document}$$ a $ $ \end{document } the change in the derived diameter is less than 0.3 m . by changing \documentclass[12pt]{minimal }
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\begin{document}$$ a $ $ \end{document}. therefore , to be able to determine fiber diameter and fiber to electrode distance a good quality of the sfp is required with sufficient resolution in time .
it is also for this reason that the graph tool can be only used for approximate or qualitative estimates as it would have to contain tens of constant \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } curves to provide comparable accuracy to the presented formulae .
from the simulation studies it has been found that the negative peak duration of sfp is a quantity which is useful in the determination of fiber properties and in particular of fiber diameter .
rodriguez and co - workers [ 6 , 7 ] have shown that this quantity is related to the width of the source current generating the potential .
we have found that \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } is related to fiber diameter .
this relation is easily understandable in view of the above findings because the duration is proportional to the ratio of the width ( ~1.5 mm ) of the negative peak of the second derivative of intracellular potential and source propagation velocity .
the velocity of propagation is dependent on fiber diameter ; therefore the larger the diameter , the less time it will take for the feature to pass the electrode , hence the negative peak duration will be shorter .
thus , it turns that \documentclass[12pt]{minimal }
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\begin{document}$$ t_{z } $ $ \end{document } is one of the basic quantities characterizing the sfp and it gives a direct link to the underlying physiology .
we have derived a set of analytical formulae using which it is possible to determine fiber diameter ( and fiber to electrode distance ) from the measurement of the sfps amplitude and negative peak duration .
the analysis of the sensitivity of the determination of fiber diameter to the errors in the measurement of amplitude and negative peak duration shows that a sampling rate of 25 khz is required so that the error in the determined fiber diameter is less than \documentclass[12pt]{minimal }
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\begin{document}$$ 8\;\mu { \text{m } } $ $ \end{document}. the errors in the determination of amplitude have much smaller impact on the error of the determination of \documentclass[12pt]{minimal }
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\begin{document}$$ d $ $ \end{document}. in order to be able to determine the fiber diameter and fiber to electrode distance , the noise level in the recorded sfp has to be low ( \documentclass[12pt]{minimal }
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\begin{document}$$ < 20$$\end{document } v ) .
it may help one to study muscle fiber diameter variability in many different muscles and thus compliment the muscle biopsy studies . | we have used computer simulation to study the relationship between the muscle fiber diameter and parameters : peak - to - peak amplitude and duration of the negative peak of the muscle fiber action potential .
we found that the negative peak duration is useful in the determination of fiber diameter via the diameter dependence of conduction velocity . we have shown a direct link between the underlying physiology and the measurements characterizing single fiber potential . using data from simulations , a graphical tool and an analytical method to estimate
the muscle fiber diameter from the recorded action potential has been developed .
the ability to quantify the fiber diameter can add significantly to the single fiber electromyography examination .
it may help study of muscle fiber diameter variability and thus compliment the muscle biopsy studies . |
controlling overweight and obesity in adolescence is a challenge for physicians and nutritionists . eating habits in this age group
are characterized by a preference for fast foods with a high fat and carbohydrate composition , with an increased rate of calories and low nutritional value .
the food preferences of adolescents can lead to obesity and overweight when combined with a sedentary lifestyle represented by long time periods dispensed to low - intensity physical activities , such as watching television and using the computer .
therefore , responsible nutritional habits should also be incorporated in official guidelines for school nutrition .
, the nutritionist or pediatrician makes a diagnosis if growth is moving away from the standard expected of disease and/or unfavorable social conditions .
the main objective of the nutritional assessment is to determine the growth and body proportions in an individual or community . as a consequence ,
earlier interventions may be imposed by improving the quality of life of the population in general .
there is no way to reduce malnutrition and obesity if they are not diagnosed correctly .
body mass index ( bmi ) or quetelet index has been established as an important diagnostic method for nutritional profile assessment in several populations . the importance of bmi has been recognized by the world health organization ( who ) . what is already known about this topic ?
first , childhood obesity is difficult to conceptualize ; and second , there is not an international consensus on the best anthropometric criteria to be used for the evaluation of overweight and obesity in adolescents .
therefore , this study aimed to evaluate the prevalence rate of underweight , overweight , and obesity among brazilian school adolescents using the cut - off points for bmi according to brazilian reference during the period between january 2014 and december 2014 .
to prevent errors in this epidemiologic study , we applied the methodological criteria recommended by the strengthening the reporting of observational studies in epidemiology guidelines .
this epidemiological design was an observational , descriptive , cross - sectional and population - based study with a cohort of school adolescents .
the sample consisted of 2162 school adolescents enrolled in all 20 government schools during the period from january 2014 to december 2014 .
assessment of anthropometric measurements body weight and height were assessed by nutritionists in schools , according to rules established by the brazilian institute of geography and statistics manual .
students were placed against the wall , barefoot , with the heels touching the wall , and the value was recorded in centimeters with one decimal place .
body weight was measured using a portable scale , with resolution up to 500 g. the students wore light clothes and were barefoot .
the value was reported in kilograms to one decimal place , and bmi was calculated as the ratio between body weight ( kilograms ) and the square of height ( m ) . in this research , as reference values for bmi in brazilian adolescents , we used the cut - off point recommended by conde and monteiro for anthropometric measurements in the brazilian population .
the age limits of adolescence are 10 years old and 19 years old according to the who .
the exclusion criteria included some conditions present in the medical reports of adolescents , such as thyroid , renal , and liver diseases , use of oral corticosteroids , anabolic steroids , and beta - blockers .
other exclusion criteria were adolescents who refused to participate in the study , student younger than 10 years and older than 19 years , pregnancy , and adolescents with special needs .
the cut - off points for bmi according to conde and monteiro ( brazilian criteria ) for students of both sexes between 10 years old and 19 years old were as follows : underweight ( bmi 17.5 kg / m ) , overweight ( bmi 25.0 kg / m ) , and obesity ( bmi 30.0 kg / m ) .
we defined period prevalence as the number of school adolescents with underweight , overweight , and obesity , divided by the total number of school adolescents in the sample .
the anthropometric evaluations were entered into microsoft office excel 2010 and exported from the database to the following software programs : graphpad prism , version 2015 ( graphpad software , inc .
san diego , california , usa ) ; ncss10 software , version 2015 ( ncss , llc , kaysville , utah , usa ) ; who anthroplus software , version 3.2.2 ( freely distributed and copied by who , geneva , switzerland ) to determine bmi ; and epitools epidemiological calculators , ( copyright 2015 by ausvet animal health services ) .
the following statistical tests were performed : ( 1 ) central limit theorem , in which very large sample size had a normal distribution .
( 3 ) student 's t - test was used with the aim of comparing differences in the arithmetic means of the normally distributed continuous variables .
( 4 ) the z - test was used to compare proportions for categorical variables . ( 5 ) the chi - square test with a trend line was used for associations among obesity and age in a contingency table , with two columns and ten rows for both sexes .
( 6 ) p < 0.05 ( two - tailed ) was considered to be statistically significant and sufficient enough to reject the null hypothesis and define a type i error .
this epidemiological design was an observational , descriptive , cross - sectional and population - based study with a cohort of school adolescents .
the sample consisted of 2162 school adolescents enrolled in all 20 government schools during the period from january 2014 to december 2014 .
assessment of anthropometric measurements body weight and height were assessed by nutritionists in schools , according to rules established by the brazilian institute of geography and statistics manual .
students were placed against the wall , barefoot , with the heels touching the wall , and the value was recorded in centimeters with one decimal place .
body weight was measured using a portable scale , with resolution up to 500 g. the students wore light clothes and were barefoot .
the value was reported in kilograms to one decimal place , and bmi was calculated as the ratio between body weight ( kilograms ) and the square of height ( m ) .
in this research , as reference values for bmi in brazilian adolescents , we used the cut - off point recommended by conde and monteiro for anthropometric measurements in the brazilian population .
the age limits of adolescence are 10 years old and 19 years old according to the who .
the exclusion criteria included some conditions present in the medical reports of adolescents , such as thyroid , renal , and liver diseases , use of oral corticosteroids , anabolic steroids , and beta - blockers .
other exclusion criteria were adolescents who refused to participate in the study , student younger than 10 years and older than 19 years , pregnancy , and adolescents with special needs .
the cut - off points for bmi according to conde and monteiro ( brazilian criteria ) for students of both sexes between 10 years old and 19 years old were as follows : underweight ( bmi 17.5 kg / m ) , overweight ( bmi 25.0 kg / m ) , and obesity ( bmi 30.0 kg / m ) .
we defined period prevalence as the number of school adolescents with underweight , overweight , and obesity , divided by the total number of school adolescents in the sample .
the anthropometric evaluations were entered into microsoft office excel 2010 and exported from the database to the following software programs : graphpad prism , version 2015 ( graphpad software , inc .
san diego , california , usa ) ; ncss10 software , version 2015 ( ncss , llc , kaysville , utah , usa ) ; who anthroplus software , version 3.2.2 ( freely distributed and copied by who , geneva , switzerland ) to determine bmi ; and epitools epidemiological calculators , ( copyright 2015 by ausvet animal health services ) .
the following statistical tests were performed : ( 1 ) central limit theorem , in which very large sample size had a normal distribution .
( 3 ) student 's t - test was used with the aim of comparing differences in the arithmetic means of the normally distributed continuous variables .
( 4 ) the z - test was used to compare proportions for categorical variables .
( 5 ) the chi - square test with a trend line was used for associations among obesity and age in a contingency table , with two columns and ten rows for both sexes .
( 6 ) p < 0.05 ( two - tailed ) was considered to be statistically significant and sufficient enough to reject the null hypothesis and define a type i error .
the number of students included in the analysis was 2162 , of which 1527 were males ( 71.0% ) and 635 were females ( 29.0% ) , with a z = 18.0 ( p = 0.00001 ) .
the arithmetic mean of age ( in years ) was 13.14 2.17 for males and 12.66 1.85 for females , with an unpaired t - test equal to 4.74 ( p = 0.0001 ) .
the coefficient of variation ( cv ) for the age of the students was 16.52% and 14.65% , respectively .
the anthropometric characteristics of all school adolescents of both sexes are shown in table 1 . the height ( cm ) , body mass ( kg ) , and bmi ( kg / m ) for males were 1.60 0.14 , 52.0 15.0 , and 20.0 4.0 , respectively . the height ( cm ) , body mass ( kg ) , and bmi ( kg / m ) for females were 1.50 0.09 , 50.0 13.0 , and 21.0 4.6 , respectively . when both sexes were compared for height , body mass , and bmi , the t values , were 7.57 ( p = 0.0001 ) , 2.47 ( p = 0.0136 ) , and 3.82 ( p = 0.0001 ) , respectively . the cv was higher than 20% for only bmi in males and females , with values between 20.02% and 22.36% , respectively .
anthropometric characteristics of all school adolescents of both sexes ( n=2162 ) table 2 shows a comparison of the bmi of underweight , overweight , and obesity in brazilian school adolescents . according to student 's t - test , there was not a statistically significant difference between the arithmetic means in both sexes for underweight ( p = 1.00 ) and obesity ( p = 0.089 ) .
however , the comparison of overweight for both sexes was statistically significant ( p = 0.044 ) .
body mass index of underweight , overweight , and obesity in brazilian school adolescents of both sexes table 3 shows the prevalence of nutritional status among the population studied using a brazilian reference for adolescents .
there was no statistically significant difference in both sexes for overweight ( z = 0.60 , p = 0.5469 ) and obesity ( z = 0.30 , p = 0.7863 ) .
however , the comparison of underweight for both sexes was statistically significant ( z = 7.80 , p = 0.001 ) .
prevalence of nutritional status in brazilian school adolescents in both sexes figure 1 shows a histogram representing the prevalence rate distribution and association with obesity and age of the school adolescents ( n = 60 ) .
the trend line shows an inverse relationship between obesity and age among the school adolescents of both sexes .
the association with a chi - square test for a linear trend was 30.95 ( p = 0.01 ) .
histogram representing the prevalence distribution and association of obesity and age of the school adolescents ( n = 60 ) .
the trend line shows an inverse relationship between obesity and age among the school adolescents for both sexes .
adolescence can be considered a transitional stage from puberty to adulthood . however , adolescence has stages of development according to different ages within this age range .
many authors have described such physical , intellectual , emotional , and social development . considering these different stages , the who mentioned many causes of illness and disability among adolescents , such as asthma and lower respiratory infections , use of alcohol , hiv / aids , anxiety , and depression , among others .
endocrine disorders were among ten top causes of death in adolescents in 2012 . in high complexity centers for diagnosis ,
thus , the main cause of obesity in adolescents and other children is exogenous factors or increased caloric intake and decreased physical activity .
it is associated with a variety of risk factors for type 2 diabetes , insulin resistance , metabolic syndrome , dyslipidemia , systemic arterial hypertension , and atherosclerosis .
there is consensus that bmi should be used in the collective assessment and perhaps individual for assessment of nutritional status in adolescents .
the height and body mass for both the sexes among school adolescents in our study [ table 1 ] was in accordance with data from brazilian institute of geography and statistics . in a government report from 2008 to 2009 ,
the median range of height among brazilian adolescents was 1.391.72 m for males and 1.4 m to 1.61 for females .
the median of body mass was reported with a range of 33.465.9 kg in males and a range of 34.356.2 kg for females .
the conde and monteiro criteria for the diagnosis of nutritional status by bmi in adolescents are shown in table 2 . however , these authors also agree that the adoption of the proposed cut - off point for underweight requires further analysis and discussion .
however , the method used in brazilian references was basically the same as that used in the calculation of the value of the international bmi standard . in this study
, the prevalence rates of underweight , overweight , and obesity observed in our population of school adolescents according to the brazilian bmi criteria were 2.8% , 8.1% , and 2.4% for males , respectively , and 23% , 10.7% , and 3.6% for females , respectively [ table 3 ] .
the prevalence rates for both sexes were similar to those of other studies that used the conde and monteiro criteria .
different from our results and those of other researchers , the prevalence of overweight and obesity was 14% and 23% , respectively , among girls in a district school in bangladesh . the prevalence rate of excess weight ( overweight and obesity ) in our school adolescents was 10.5% for boys and 14.3% for girls .
. found similar results with the national criteria in a sample of 3118 school adolescents in the northern region of brazil , i.e. , 11.6% and 14.6% prevalence of excess weight for boys and girls , respectively .
flores et al . showed a prevalence rate of 27.6% for boys and 33.8% for girls .
our results in figure 1 show a statistically significant inverse association between obesity prevalence and age in school adolescents .
the choice of the brazilian reference for the calculation of prevalence rates of anthropometric status in adolescents can be compared to other international criteria .
international references for comparisons of the prevalence rate are 518% for overweight and 0.14% for obesity at 218 years old .
the results of our study are in the international reference range as shown in table 3 . however , the prevalence rate of underweight in our population was very high among girls ( 23.0% ) compared to boys ( 2.8% ) and was statistically significant ( p = 0.001 ) , as shown in table 3 .
an international study of the trends of obesity and underweight in many countries showed that the prevalence rate of underweight was 6.5% among girls in 1997 in brazil . in 12 schools of bhubaneswar , state of odisha , india ,
the prevalence of overweight and obesity among adolescents in private schools was significantly higher ( 45.2% ) than those in government schools ( 10.5% ) .
what are the implications ? we recommend bmi as the best procedure for monitoring and diagnosing obesity in health campaigns .
this study concludes that the occurrence of excess weight among our school adolescents was similar to the international prevalence .
however , the prevalence rate of underweight in our population was very high among girls ( 23.0% ) .
the results of the diagnosis of nutritional status of every adolescent were sent with knowledge of the parents .
the current study can not be extrapolated to the entire population of brazilian adolescent students because this research was conducted with a specific population group .
the nutritional status of adolescents must be considered to be a public health problem in brazil .
| introduction : the nutritional profile of the brazilian population has changed in recent years . therefore , this study aimed to assess the prevalence of nutritional status among brazilian school adolescents during the period from january 2014 to december 2014.methods:this study employed an observational design with a cohort of school adolescents .
anthropometric measurement was assessed by nutritionists in government schools .
the cut - off points for body mass index according to brazilian criteria for adolescents of both sexes between 10 years and 19 years old were underweight ( 17.5 kg / m2 ) , overweigh ( 25.0 kg / m2 ) , and obesity ( 30.0 kg / m2).results : the number of students included in the analysis was 2162 , of which 71.0% were males and 29% were females ( p = 0.00001 ) .
the mean age ( years ) was 13.14 2.17 for boys and 12.66 1.85 for girls ( p = 0.0001 ) .
the prevalence of underweight , overweight , and obesity observed in our population of school adolescents according to the brazilian criteria was 2.8% , 8.1% , and 2.4% for males , respectively , and 23.0% , 10.7% , and 3.6% for females , respectively . for both sexes
, there was no statistically significant difference between overweight ( p = 0.5469 ) and obesity ( p = 0.7863 ) , but there was for underweight ( p = 0.001).conclusions : the occurrence of excess weight among brazilian school adolescents is similar to the international prevalence , but the prevalence of underweight was very high among girls . the nutritional status of adolescents must be considered a public health problem in brazil . |
cerebral venous thrombosis ( cvt ) is a rare form of stroke with an estimated incidence of 1.3 per 100.000 among adults .
thrombosis of the sinuses leads to impairment of cerebral spinal fluid drainage and venous outflow , which often causes increased intracranial pressure , with symptoms such as headache , papilledema and 6th nerve palsy [ 24 ] .
hydrocephalus , however , is rarely reported in patients with cvt and few studies have investigated this complication .
cohort studies of cvt reported incidences of hydrocephalus between 0.2 and 6.6 % [ 57 ] .
however , hydrocephalus was not a major research topic in any of these studies and specific definitions or details are not provided .
all studies also lacked central review of imaging data and the validity of the estimates provided by these studies is , therefore , questionable . in fact , the only detailed reports on hydrocephalus in patients with cvt are case reports [ 812 ] .
the aim of the present study was to systematically examine the incidence , risk factors , pathophysiology , associated clinical manifestations , and outcome of hydrocephalus in a large cohort of consecutive patients with cvt .
we included consecutive patients with cvt aged 12 and older admitted to the academic medical centre ( university of amsterdam ) between january 1st 2000 and january 1st 2011 .
since july 2006 , all patients with cvt are enrolled in a prospective database , as described previously .
we retrospectively identified patients admitted between january 1st 2000 and june 30th 2006 , using the international classification of diseases , 9th revision and the dutch financial coding system for hospital care .
cvt was confirmed in all patients by one of the following magnetic resonance imaging ( mri ) with mri - venography , computed tomographic - venography ( ct - v ) , conventional angiography , or autopsy .
clinical outcome was classified according to the modified rankin scale ( mrs ) , a 7-point scale which ranges from 0 ( complete recovery ) to 6 ( dead ) .
we defined good outcome as a mrs score of 0 or 1 at last follow - up .
patients admitted before july 2006 for whom no mrs had been recorded were contacted by telephone to determine the score by means of a structured interview . under dutch law ,
all cerebral imaging results were re - evaluated by two neuroradiologists ( rvdb and cbm ) .
the type of scan , location of the thrombosis , presence and type of intracranial lesions , and the presence of hydrocephalus were documented .
we determined the presence of hydrocephalus by measuring the bicaudate index ( bci ) and the radial width of the temporal horn ( rwth ) , as described previously [ 15 , 16 ] .
briefly , the bci is the width of the frontal horns at the level of the caudate nuclei and the foramen of monro divided by the corresponding width of the brain at the same level . to calculate age - adjusted relative sizes ,
the bcis were divided by the corresponding upper limit ( 95th percentile ) per age group , as previously reported .
the rwth of the lateral ventricle was measured at the tip of the temporal horn on ( axial ) imaging using the method described by frisoni et al . .
the rwth was measured at the image slice where the temporal horn was the widest .
two parallel lines were drawn tangential to the margins of the temporal horn at its widest point .
because control values for the rwth have not been published , we measured the rwth in a control group of healthy adults . for each patient with cvt
, we selected an age - matched control patient who underwent cranial ct imaging because of a minor head injury between 2010 and 2012 . only patients without neurological co - morbidity and in whom the ct scan was unremarkable ( without any traumatic injuries ) were eligible as controls .
we defined hydrocephalus as one of the following a bci above the 95th percentile for age , and/or a rwth ( uni- or bilateral ) 2.5 standard deviations or more above the mean rwth of the control group .
presence of hydrocephalus was determined on baseline imaging and on follow - up scans performed within 30 days of diagnosis .
if a patient had hydrocephalus on multiple examinations , we used the scan in which the hydrocephalus was most severe .
we excluded patients in whom hydrocephalus was caused by a disease other than cvt or if it was deemed iatrogenic ( e.g. following decompressive hemicraniectomy ) . for categorical variables , we used the pearson or fisher s exact test if appropriate . the student s t test or mann whitney test ( for skewed distributions ) were used for continuous variables . to determine whether hydrocephalus was associated with outcome , we performed multivariate logistic regression analysis .
we included consecutive patients with cvt aged 12 and older admitted to the academic medical centre ( university of amsterdam ) between january 1st 2000 and january 1st 2011 .
since july 2006 , all patients with cvt are enrolled in a prospective database , as described previously .
we retrospectively identified patients admitted between january 1st 2000 and june 30th 2006 , using the international classification of diseases , 9th revision and the dutch financial coding system for hospital care .
cvt was confirmed in all patients by one of the following magnetic resonance imaging ( mri ) with mri - venography , computed tomographic - venography ( ct - v ) , conventional angiography , or autopsy .
clinical outcome was classified according to the modified rankin scale ( mrs ) , a 7-point scale which ranges from 0 ( complete recovery ) to 6 ( dead ) .
we defined good outcome as a mrs score of 0 or 1 at last follow - up .
patients admitted before july 2006 for whom no mrs had been recorded were contacted by telephone to determine the score by means of a structured interview . under dutch law ,
all cerebral imaging results were re - evaluated by two neuroradiologists ( rvdb and cbm ) .
the type of scan , location of the thrombosis , presence and type of intracranial lesions , and the presence of hydrocephalus were documented .
we determined the presence of hydrocephalus by measuring the bicaudate index ( bci ) and the radial width of the temporal horn ( rwth ) , as described previously [ 15 , 16 ] .
briefly , the bci is the width of the frontal horns at the level of the caudate nuclei and the foramen of monro divided by the corresponding width of the brain at the same level . to calculate age - adjusted relative sizes ,
the bcis were divided by the corresponding upper limit ( 95th percentile ) per age group , as previously reported .
the rwth of the lateral ventricle was measured at the tip of the temporal horn on ( axial ) imaging using the method described by frisoni et al . .
the rwth was measured at the image slice where the temporal horn was the widest .
two parallel lines were drawn tangential to the margins of the temporal horn at its widest point .
because control values for the rwth have not been published , we measured the rwth in a control group of healthy adults . for each patient with cvt
, we selected an age - matched control patient who underwent cranial ct imaging because of a minor head injury between 2010 and 2012 . only patients without neurological co - morbidity and in whom the ct scan was unremarkable ( without any traumatic injuries ) were eligible as controls .
we defined hydrocephalus as one of the following a bci above the 95th percentile for age , and/or a rwth ( uni- or bilateral ) 2.5 standard deviations or more above the mean rwth of the control group .
presence of hydrocephalus was determined on baseline imaging and on follow - up scans performed within 30 days of diagnosis .
if a patient had hydrocephalus on multiple examinations , we used the scan in which the hydrocephalus was most severe .
we excluded patients in whom hydrocephalus was caused by a disease other than cvt or if it was deemed iatrogenic ( e.g. following decompressive hemicraniectomy ) .
for categorical variables , we used the pearson or fisher s exact test if appropriate . the student s t test or mann whitney test ( for skewed distributions ) were used for continuous variables . to determine whether hydrocephalus was associated with outcome , we performed multivariate logistic regression analysis .
the mean rwth in the age - matched control group ( no cvt ) was 1.8 mm with a standard deviation of 1.2 mm .
therefore , the upper limit of normal for the rwth was defined as 5 mm . during the study period ,
99 patients with cvt older than 12 were admitted , of whom 59 after july 2006 ( prospective cohort ) .
twenty of these patients ( 20 % ) had hydrocephalus ( fig . 1 ) .
six patients were excluded from the analysis because the hydrocephalus was iatrogenic or had another cause [ after decompressive hemicraniectomy ( 3 ) ; complication of endovascular thrombolysis ( 2 ) and hydrocephalus due to a teratoma ( 1 ) ] .
therefore , the study cohort consisted of 14 patients with and 79 patients without hydrocephalus . in 10 of 14 patients ( 71 % )
hydrocephalus was found within 24 h of diagnosis ( 3 patients ) or 8 days after diagnosis ( 1 patient ) .
thirteen patients ( 93 % ) had an increased rwth ( bilateral in 8) and only 2 ( 14 % ) had an increased bci ( table 1 ) .
the mean rwth was 6.5 mm in the patients with hydrocephalus , compared to 2.1 mm in those without hydrocephalus . at baseline ,
patients with hydrocephalus more often had focal neurological deficits ( 86 vs. 49 % , p = 0.02 ) , fixed and dilated pupil(s ) ( 14 vs. 1 % , p = 0.06 ) , and a lower glasgow coma scale ( median 10 vs. 15 , p = 0.01 ) as compared to patients without hydrocephalus .
lumbar puncture was performed in four patients with hydrocephalus , and all had an increased cerebrospinal fluid pressure ( > 20 cm h2o ) . in patients without hydrocephalus ,
1flowchart of patient selectiontable 1baseline characteristicshydrocephalus ( n = 14)no hydrocephalus ( n = 79 )
p valuehydrocephalus details increased rwth13/14 ( 93 % ) na bilateral8/14 ( 57 % ) na mean rwth ( mm , sd)6.5 ( 1.8)2.1 ( 1.4)na increased bci2/14 ( 14 % ) na mean bci ( sd)0.13 ( 0.04)0.11 ( 0.03)na hydrocephalus at baseline10/14 ( 71 % ) nademographics female13/14 ( 93 % ) 53/79 ( 67 % ) 0.06 mean age ( sd)33 ( 16)37 ( 13)>0.1symptoms and signs duration symptom onset to diagnosis ( days , median , iqr)5 ( 212)4 ( 27)>0.1 duration admission to diagnosis ( days , median , iqr)0 ( 01)1 ( 02)>0.1 headache13/14 ( 93 % ) 67/79 ( 85 % ) > 0.1 focal neurological deficit12/14 ( 86 % ) 38/77 ( 49 % ) 0.02 seizure(s)3/14 ( 21 % ) 27/79 ( 34 % ) > 0.1 glasgow coma scale ( median , iqr)10 ( 814)15 ( 1115)0.01 coma6/14 ( 43 % ) 12/73 ( 16 % ) 0.06 fixed and dilated pupil(s)2/14 ( 14 % ) 1/79 ( 1 % ) 0.06
rwth radial width of the temporal horn , bci bicaudate index , sd standard deviation , iqr interquartile range flowchart of patient selection baseline characteristics
rwth radial width of the temporal horn , bci bicaudate index , sd standard deviation , iqr interquartile range patients with hydrocephalus more often had thrombosis of the straight sinus ( 64 vs. 23 % , p = 0.002 ) and deep cerebral venous thrombosis ( dcvt : internal cerebral veins , vein of galen , and/or the basal vein of rosenthal ; 64 vs. 9 % , p < 0.001 , table 2 ) .
in contrast , the superior sagittal sinus was less often involved in patients with hydrocephalus ( 21 vs. 67 % , p = 0.001 ) .
hypodensity of the basal ganglia and/or thalami on ct , suggesting edema , was present in 9/14 ( 64 % ) patients with hydrocephalus , as compared to 3/79 ( 4 % ) in those without hydrocephalus ( p < 0.001 ) . in two of these nine patients ,
there was no difference in frequency of baseline intracerebral hemorrhages between the two groups ( 50 vs. 54 % ) .
intraventricular extension of the hemorrhage was present in one patient with hydrocephalus at baseline , compared to none among patients without hydrocephalus ( 7 vs. 0 % , p = 0.15 ) .
this patient had a small amount of blood in the right occipital horn of the lateral ventricle.table 2radiological findings , treatment and outcomehydrocephalus ( n = 14)no hydrocephalus ( n = 79 )
p valuethrombosed sinuses superior sagittal sinus3/14 ( 21 % ) 53/79 ( 67 % ) 0.001 lateral sinus ( left and/or right)12/14 ( 86 % ) 59/79 ( 75 % ) > 0.1 straight sinus9/14 ( 64 % ) 18/78 ( 23 % ) 0.002 deep cerebral venous system
9/14 ( 64 % ) 7/79 ( 9 % ) <
0.001 thrombosis > 1 sinus13/14 ( 93 % ) 67/79 ( 85 % ) > 0.1parenchymal lesions edema basal ganglia / thalami
9/14 ( 64 % ) 3/79 ( 4 % ) < 0.001 intracerebral hemorrhagic lesion7/14 ( 50 % ) 43/79 ( 54 % ) > 0.1 intraventricular hemorrhage1/14 ( 7 % ) 0/79 ( 0 % ) 0.15treatment heparin treatment13/14 ( 93 % ) 79/79 ( 100 % ) > 0.1 endovascular treatment9/14 ( 64 % ) 14/78 ( 18 % ) < 0.001 decompressive hemicraniectomy3/14 ( 21 % ) 6/78 ( 8 % ) > 0.1 ventricular shunting procedure1/14 ( 7 % ) 2/79 ( 3 % ) > 0.1clinical outcome at last follow - up duration of follow - up ( median months , iqr)16 ( 275)8 ( 424)>0.1 mrs 01 ( recovery without handicap)5/14 ( 36 % ) 50/74 ( 68 % ) 0.02 mortality at follow - up4/14 ( 29 % ) 7/75 ( 9 % ) 0.07
iqr
interquartile range , mrs modified rankin scale
deep cerebral venous system was defined as thrombosis in one or more of the following veins : internal cerebral veins , vein of galen , and basal vein of rosenthal
confirmed by mri in 2/9 patients with hydrocephalus radiological findings , treatment and outcome
iqr interquartile range , mrs modified rankin scale
deep cerebral venous system was defined as thrombosis in one or more of the following veins : internal cerebral veins , vein of galen , and basal vein of rosenthal
confirmed by mri in 2/9 patients with hydrocephalus three different patterns of hydrocephalus could be discerned .
the largest group consisted of patients with an increased rwth , deep cerebral venous thrombosis and edema of the basal ganglia and thalami ( fig .
the bci was normal in all of these patients , and only one had thrombosis of the superior sagittal sinus .
the next group consisted of three patients with an increased unilateral rwth due to mass effect from a contralateral intracerebral hemorrhage ( fig .
2c , d ) . finally , two patients had an increased bci without parenchymal lesions or thrombosis of the deep venous system .
both these patients had superior sagittal sinus thrombosis , without involvement of the deep veins.fig .
a , b axial fluid attenuated inversion recovery ( flair ) mri showing extensive edema in the thalami , basal ganglia and brainstem , and hydrocephalus of both temporal horns ( arrows ) .
c , d axial non - contrast - enhanced ct scan of a different patient showing a large space occupying intracranial hemorrhage in the left hemisphere , and an increase of width of the contralateral temporal horn cerebral imaging of two patients with hydrocephalus .
a , b axial fluid attenuated inversion recovery ( flair ) mri showing extensive edema in the thalami , basal ganglia and brainstem , and hydrocephalus of both temporal horns ( arrows ) .
c , d axial non - contrast - enhanced ct scan of a different patient showing a large space occupying intracranial hemorrhage in the left hemisphere , and an increase of width of the contralateral temporal horn autopsy was performed in one patient with hydrocephalus and dcvt .
figure 3 shows a coronal section of the brain demonstrating widening of the temporal horns and small petechial hemorrhages and infarcts in the thalami . the third ventricle and foramen of monro
. coronal section of the brain showing enlargement of the temporal horns ( arrows ) .
small petechial hemorrhages and infarcts are present bilaterally in the thalami ( arrowhead ) . the third ventricle and foramen of monro
are narrowed all patients except one ( in whom cvt was not diagnosed until autopsy ) received treatment with therapeutic doses of heparin ( table 2 ) .
patients with hydrocephalus more often were treated with endovascular thrombolysis ( 64 vs. 18 % , p < 0.001 ) and more often underwent decompressive hemicraniectomy ( 21 vs. 8 % , p > 0.1 ) .
one patient with hydrocephalus received an external ventricular drain , which was done prior to the diagnosis of cvt .
this shunting procedure was done because of clinical worsening ( decrease in consciousness ) and for diagnostic reasons . at that time
bacterial meningitis was considered the most likely diagnosis and previous attempts to obtain cerebrospinal fluid through lumbar puncture had failed .
she suffered from acute lymphoblastic leukemia , which was diagnosed several hours after placement of the drain and died as a result of a massive intraventricular hemorrhage 1 day after admission .
two patients without hydrocephalus received a ventricular peritoneal drain because of intracranial hypertension with severe papilledema and impending blindness .
follow - up information on clinical outcome was available for 88 of the 93 patients ( 95 % ) . while the duration of follow - up was non - significantly longer for patients with hydrocephalus ( 16 vs. 8 months , p > 0.1 ) , patients with hydrocephalus less often had a good outcome at last available follow - up ( 36 vs. 68 % , p = 0.02 ) .
mortality was also higher in patients with hydrocephalus ( 29 vs. 9 % , p = 0.07 ) .
after adjustment for baseline clinical imbalances ( gender , focal neurological deficits , coma , and fixed pupils ) , however , hydrocephalus was not an independent predictor of outcome ( adjusted or for mrs 01 : 0.67 , 95 % ci 0.152.92 ) .
this is the first study on hydrocephalus in a large cohort of consecutive patients with cerebral venous thrombosis .
our data show that hydrocephalus predominantly occurs in patients with deep cerebral venous thrombosis and edema of the basal ganglia and thalami . in all patients with this pattern ,
it is unlikely that hydrocephalus in these patients is due to a diminished resorption of cerebrospinal fluid by the arachnoid villi .
the majority of these villi are located in the superior sagittal sinus , which was rarely occluded in these patients .
a more plausible explanation and also consistent with the pattern of hydrocephalus , is that the flow of cerebrospinal fluid ( csf ) through the foramen of monro is obstructed due to local compression by edema of the basal ganglia and/or thalami .
the autopsy results are in agreement with this hypothesis . considering the pivotal role of the arachnoid villi in the drainage of csf , one may wonder why cvt does not result in hydrocephalus more often , especially in cases with thrombosis of the superior sagittal sinus .
many of these patients have increased intracranial pressure , but hydrocephalus occurred only in 2/55 patients with thrombosis of the superior sagittal sinus in our cohort .
the most likely explanation is that there is no pressure gradient of the csf in these cases between the ventricular and subarachnoid compartments at the cerebral convexity .
a similar mechanism has been proposed in patients with cryptococcal meningitis and increased intracranial pressure , who generally also do not have hydrocephalus .
intraventricular extension of hemorrhage may also be a contributing factor to the development of hydrocephalus , but this occurred only in one patient .
the frequency of hydrocephalus was much higher in our cohort than previously reported [ 512 ] .
first , our hospital is a tertiary referral center for patients with a severe form of cvt .
21 % of our patients was in coma at baseline and 17 % had dcvt , which is both higher than in other cohort studies [ 2 , 19 ] .
a second explanation is that most studies did not focus on hydrocephalus , which probably leads to an underestimation of its frequency . despite aggressive treatment with endovascular thrombolysis and decompressive hemicraniectomy in many patients ,
after correction for baseline imbalances , however , hydrocephalus was not an independent predictor of outcome .
hydrocephalus is probably a marker of a severe form of cvt , associated with edema of the basal ganglia / thalami caused by dcvt .
dcvt is a well - known predictor of poor outcome . since a causal relation between hydrocephalus and poor outcome is unlikely , the risks of shunting procedures and the fact that patients with cvt require treatment with anticoagulation , we do not recommend routine shunting procedures in patients with cvt and hydrocephalus .
generally , we will only consider an external ventricular drain in these patients if they are in a worse clinical condition than would be expected on the extent of the parenchymal lesions or if they deteriorate without apparent cause other than the hydrocephalus . in patients who additionally have seizures , the decision whether or not to perform a shunting procedure is even more difficult , since these patients often have fluctuations in their consciousness .
the other situation when a shunting procedure should be considered in cvt is in patients with severe intracranial hypertension ( usually without hydrocephalus ) that comprises visual function or , rarely , cerebral perfusion .
our study has some limitations first , the rwth is less often used for the determination of hydrocephalus than the bci . since cutoff values for a normal rwth
were not available in the literature , we determined the upper normal value by measuring the rwth in a cohort of age - matched patients .
another limitation is that mri which is clearly superior to determine the extent of edema of the basal ganglia was only available in a minority of patients .
however , since all imaging data were re - evaluated and outcome was available for almost all patients , we do not think this influences the validity of the results . in conclusion
, we found that hydrocephalus is more common in patients with cerebral venous thrombosis than previously believed .
hydrocephalus mainly occurs in patients with deep cerebral venous thrombosis and edema of the basal ganglia and thalami , probably because of obstruction of the foramen of monro .
the presence of hydrocephalus is associated with a worse clinical outcome , but a direct causal relation is unlikely . | increased intracranial pressure is common in cerebral venous thrombosis ( cvt ) , but hydrocephalus is rarely reported in these patients .
we examined the frequency , pathophysiology and associated clinical manifestations of hydrocephalus in patients with cvt admitted to our hospital between 2000 and 2010 ( prospectively since july 2006 ) .
hydrocephalus was defined as a bicaudate index larger than the 95th percentile for age , and/or a radial width of the temporal horn of 5 mm .
we excluded patients in whom hydrocephalus was caused by a disease other than cvt or if it was iatrogenic .
20 out of 99 patients with cvt had hydrocephalus .
6 patients with hydrocephalus were excluded from the analysis .
patients with hydrocephalus more often had focal neurological deficits ( 86 vs. 49 % , p = 0.02 ) and were more frequently comatose ( 43 vs. 16 % , p = 0.06 ) , as compared to patients without hydrocephalus .
deep cerebral venous thrombosis ( 64 vs. 9 % , p < 0.001 ) and edema of the basal ganglia and thalami ( 64 vs. 4 % , p <
0.001 ) were more common in patients with hydrocephalus .
intraventricular hemorrhage was present in 1 patient with hydrocephalus , compared to none among patients without hydrocephalus ( 7 vs. 0 % , p = 0.15 ) .
outcome at follow - up was worse in patients with hydrocephalus ( mrs 01 , 36 vs. 68 % , p = 0.02 ; mortality 29 vs. 9 % , p = 0.07 ) .
hydrocephalus occurs more frequently in cerebral venous thrombosis than previously believed , especially in patients with deep cerebral venous thrombosis and edema of the basal ganglia .
the presence of hydrocephalus is associated with a worse clinical outcome , but a direct causal relation is unlikely .
routine shunting procedures are not advisable . |
lower urinary tract symptoms ( luts ) in aging men have historically been ascribed to enlargement of the prostate gland referred to as benign prostatic hyperplasia ( bph ) . however , there is growing appreciation that the genesis of luts is likely multifactorial and , in addition to prostate enlargement , is likely to include age - related changes in bladder function , autonomic dysregulation , and metabolic influences .
recently , prostate inflammation was identified as very strongly associated with severity of symptoms and prostatic fibrosis was associated both with irritative voiding symptoms such as urinary frequency and urgency and with diminished urine flow [ 2 , 3 ] .
men diagnosed with symptomatic bph have a higher incidence of diabetes than the general population .
postulated mechanisms for this association include increased sympathetic tone , stimulation of prostate growth by insulin , alterations in steroid hormone secretion , inflammation , and oxidative stress .
given recent clinical studies implicating prostate inflammation and fibrosis in the genesis of luts , we examined the prostate of mouse model of type 1 diabetes ( dba2j.ins2-akita ) for evidence of inflammation and/or fibrosis .
this work was supported as a pilot study by the nih animal model of diabetic complication consortium ( amdcc ) .
heterozygous dba2j.ins2-akita ( akita ) female and male mice ( the jackson laboratory , strain number 007562 , bar harbor , me ) were obtained for breeding . all procedures in this study
were performed with 18-week - old heterozygous akita male mice and wild type controls ( wt ) as approved by the institutional animal care and use committee , university of wisconsin - madison .
the tip of the tail from each male adult mouse were collected and sent to transnetyx , inc . for genotyping ( cordova , tn ) . at 18 weeks of age
, each prostatic lobe ( ap , dlp , and vp ) was identified as described earlier and harvested .
collected anterior prostate , dorsal lateral prostate ( dlp ) , and ventral prostate ( vp ) were rinsed in dpbs and fixed in 10% formalin .
three random areas from each prostatic lobe from each animal were acquired for h&e ( thermo scientific , waltham , ma , anatech ltd , battle creek , mi ) staining ( wt : n
the number and type of inflammatory cells were characterized in the prostate of akita and wt mice .
three random areas from each prostatic lobe from each animal were acquired ( wt : n
immunohistochemistry was used to quantitate monocytes / macrophages , t lymphocytes , b lymphocytes , and fibrocytes .
briefly , sections were blocked for 4 hours in pbs containing 10% donkey serum and 1% bsa ( both from sigma - aldrich , st .
louis , missouri ) was followed by primary antibodies - rat anti - f4/80 ( 1 : 50 , ebioscience , san diego , ca ) , rabbit anti - cd3 ( 1 : 100 , dako , carpinteria , ca ) and goat anti - cd20 ( 1 : 100 , santa cruz , santa cruz , ca ) , and rat anti - cd45 ( 1 : 100 , abcam , cambridge , ma ) and rabbit anti - vimentin ( 1 : 100 , abcam , cambridge , ma ) overnight at 4 degrees .
secondary antibodies - donkey anti - rat alexa 594 , donkey anti - rabbit alexa 594 , donkey anti - rat alexa 488 , and donkey anti - goat alexa 488 ( 1 : 100 , invitrogen , grand island , ny ) were incubated for one hour at room temperature .
for quantification of each cell type , three random areas from each prostatic lobe from each animal were acquired using nikon eclipse ti - u microscope .
paraffin embedded tissues were incubated in 0.1% sirius red solution for an hour at room temperature .
three random areas from each prostatic lobe from each animal were acquired ( wt : n = 4 ; diabetic : n = 4 ) using a spot - advanced camera on an olympus bx51 microscope . areas of positive staining were quantitated using macbiophotonics image j. comparisons within each prostatic lobe between akita and wt mice were performed by a two - sample t - test .
we employed anova with multiple comparisons using fisher 's protected least significant difference tests . prior
to analysis , all values were rank - transformed in order to better meet the assumptions of anova .
all analysis was performed using sas statistical software versions 9.1 and 9.2 ( sas institute inc . , cary , nc ) .
prostate lobes from 18-week - old akita and wt mice were examined for evidence of tissue injury and inflammation by routine h&e staining and scoring according to a previously published scoring system .
we observed no evidence of increased tissue damage , epithelial atypia or atrophy , or reactive hyperplasia .
mild inflammation was observed in all wt mice examined and three of four akita mice ( figures 1(a ) , 1(b ) , 1(d ) , 1(e ) , 1(g ) , and 1(h ) ) .
the prostate from one akita mouse exhibited severe inflammation ( figures 1(c ) , 1(f ) , and 1(i ) ) . in order to identify any qualitative difference in the inflammatory infiltrate in wt and akita mice , we performed immunostaining for different inflammatory cell subsets ( figure 2 ) . for both wt and akita mice ,
this comparison revealed no difference in the number of neutrophils , t lymphocytes , or b lymphocytes between the wt and akita mice .
however , the number of monocytes / macrophages was significantly increased in the vp and ap of akita mice as compared to wt . when the one akita mouse with severe inflammation was excluded from the analysis ,
we performed picrosirius red staining to compare collagen content in the wt and akita mice .
we observed significantly increased staining in the vp of akita mice , a difference that remained significant even when we excluded the akita mouse with severe inflammation ( figure 3 ) .
these cells originate from bone - marrow derived circulating monocytes and have an intermediate phenotype of fibroblasts and macrophages .
costaining for cd45 and vimentin was performed to identify and quantitate fibrocytes in the prostate lobes of wt and akita mice .
the number of fibrocytes was significantly increased in the vp of akita mice as compared to wt controls ( figure 4 ) .
the number of fibrocytes was still significantly increased in the vp even when we excluded the animal with severe inflammation .
our studies revealed increased collagen content in the vp of akita mice as compared to age - matched controls .
picrosirius red staining is considered a reliable indicator of collagen content and has been tightly correlated with tissue hydroxyproline content by a colorimetric assay and hplc ( manuscript in preparation ) . increased picrosirius red staining
can result from increased collagen synthesis , decreased collagen degradation , or enhanced collagen cross - linking .
these are all changes associated with persistent wound healing a feature of repeated injury , chronic inflammation , and prolonged cytokine release and are cardinal aspects of fibrosis [ 10 , 11 ] .
the specificity of fibrosis for the vp of the akita mouse is unexplained ; however , it does echo a previous report of thickened collagen fibrils in the vp of a type 1 diabetic rat [ 12 , 13 ] .
similarly , cagnon et al . reported thickening of the extracellular matrix and reduced cell height of glandular epithelium in the vp of streptozotocin - treated mice .
one of the things that confounds prostate research in rodents is the lack of correlation between the lobes of the rodent prostate and the zones of the human prostate as the anatomic and gene expression profiles for the lobes and zones are incongruent .
work in various models has shown changes both in the vp [ 1214 ] and in the dlp [ 16 , 17 ] .
these studies resonate with a larger body of work reporting an association of tissue inflammation and fibrosis in multiple organ systems in diabetes [ 6 , 1823 ] .
it has been previously reported that tissue injury and inflammation and/or senescence results in increased collagen deposition [ 10 , 16 ] . however , histologic examination and scoring of tissue damage and inflammation revealed no increase in tissue damage or generalized inflammatory infiltrate in the vp of akita mice as compared to wt controls .
however , we observed that monocyte / macrophage infiltration was significantly increased in the vp and ap of akita mice as compared to wt controls .
monocyte / macrophage infiltration is a feature of cellular immunity that has been noted in the glomeruli of akita mice and streptozotocin - induced diabetic mice and speculated to be the source of proinflammatory cytokines that promote glomerulosclerosis .
given these precedent findings , our observations might reflect a functional connection between monocyte / macrophage infiltration and vp fibrosis .
recent studies have identified fibrocytes as having a primary role in collagen synthesis in tissue remodeling and inflammation .
these cells are bone marrow derived cells that take up residence in the tissue and exhibit costaining for cd45 and vimentin .
our unpublished studies of bacterial - induced prostate inflammation show robust numbers of cd45+/vimentin+ cells that costain for prolyl-4-hydroxylase , an enzyme catalyzing the formation of 4-hyroxyproline .
we found that cd45+/vimentin+ cells were significantly increased in the vp of akita mice and suggest a role for fibrocytes in vp fibrosis .
. postulated mechanisms include accelerated rates of prostatic enlargement , bladder muscle dysfunction , and neuropathic effects on bladder function [ 2 , 28 , 29 ] .
given recent studies suggesting that fibrosis of the prostate produces a change in prostatic compliance that impairs opening of the bladder neck during voiding , our studies suggest that fibrosis instigated by monocyte / macrophage infiltration may be one mechanism by which diabetes contributes to development of luts in men .
the possible effect of prostate fibrosis on opening of the bladder neck is uniquely important in humans because the encapsulated prostate completely surrounds the bladder neck and urethra . since the prostate in mice
is not encapsulated and the arrangement of the prostate and bladder neck is such that fibrosis would not be expected to impinge on either the bladder neck or urethra , we are unable to specifically evaluate the effect of the fibrosis we observe on voiding function in this model .
even so , it is a valuable model in which mechanistic studies may be performed to understand how diabetes - induced inflammation induces prostatic fibrosis .
these observations support the inference that diabetes elicits monocyte / macrophage / fibrocyte infiltration and collagen accumulation in the ventral prostate and suggest that further study of akita mice may inform translational studies of diabetes in the genesis of bph , prostatic inflammation and fibrosis , and luts . | a higher incidence of lower urinary tract symptoms ( luts ) among diabetic men is unexplained .
recently , prostate inflammation and fibrosis have been implicated as major contributing factors to bladder outlet obstruction and luts .
we characterized the inflammatory cell infiltrate and collagen content of the anterior , dorsal , and ventral lobes of 18-week - old dba2j.ins2-akita mice ( akita ) and age - matched control mice .
we performed hematoxylin and eosin staining to score tissue injury and inflammation , picrosirius red staining to quantitate collagen content , and immunostaining to identify monocytes / macrophages and infiltrating fibrocytes .
we observed significantly greater numbers of monocytes / macrophages and fibrocytes specifically in the ventral prostate of the akita mice and found that this was associated with significant greater collagen content specifically in the ventral prostate of the akita mice .
these observations support the inference that diabetes elicits monocyte / macrophage infiltration and collagen accumulation in the prostate and suggest that further study of akita mice may inform translational studies of diabetes in the genesis prostatic inflammation , prostatic fibrosis , and luts . |
the uremic state is associated with an altered immune response ( 2 ) and intermittent stimulation by endotoxins from the dialysis water supply and artificial vein grafts or bio incompatibility caused the increased inflammatory proteins , such as c - reactive protein ( crp ) ( 3 ) .
in addition to inflammatory marker , crp as a mediator for developing atherosclerosis , directly affect endothelial cells , monocytes - macrophages and smooth muscle cells .
crp is produced by the liver under the control of various proinflammatory cytokines , but mainly by hepatocytes in response to il-6 . among the various cytokines ,
il-6 was found to be most closely related to mortality in both hemodialysis and pre dialysis patients ( 5 ) and to be associated with more causes of inflammation than other cytokines ( 6 ) .
il-6 increases the risk of atherosclerosis through metabolic , endothelial and coagulant mechanisms . in hemodialysis patients elevation of il-6
inflammation is associated with a prothrombotic tendency even in acute renal disease ( 8) . among the non - classic cardiovascular risk factors , plasma fibrinogen ,
d - dimer and von willebrand factor ( vwf ) , are potential markers of cardiovascular morbidity ( 9 ) .
renal dysfunction is identified as a state of activated coagulation due to the elevated d - dimer levels , which are not cleared by the kidney ( 11 ) .
the vwf , a marker of endothelial injury , showed a positive correlation with total mortality in the hemodialysis patients .
chronic endothelial cell activation , but not platelet activation , is related to all - cause mortality in patients in chronic hemodialysis ( 12 ) . in this context
, renal failure can be viewed as a clinical model of mild , protracted systemic inflammation that is intrinsically associated with endothelial dysfunction and hemostatic activation , which are all important mediators of atherosclerosis and thrombotic events .
the contribution of cardiovascular events to the extraordinary high mortality in end - stage - renal disease has generated some interest in non - traditional atherosclerotic risk factors , such as lipoprotein ( a ) [ lp(a ) ] .
high concentrations of lp(a ) are considered a major risk factor for atherosclerosis ( 13 ) .
lp(a ) is frequently elevated in hemodialysis patients ( 14 ) . in hemodialysis patients ,
the structure and function of the fibrin clot are modulated by several environmental and genetic factors .
lp(a ) ( 15 ) and crp ( 16 ) , which along with fibrinogen are significantly elevated have also been reported to reduce clot permeability and susceptibility to lysis ( 17 ) .
hypoalbuminemia is associated with cardiovascular disease in general population as well as in hemodialysis patients .
it has been found a significant correlation of il-6 and hypoalbuminemia which is considered as a powerful predictor of mortality ( 18 ) .
a significant inverse relationship was also found between lp(a ) and albumin ( 19 ) .
the aim was to study relationships between inflammation , lp(a ) and hypercoagulability in hemodialysis patients with no evidence of cardiovascular disease .
in this study were included 78 patients , undergoing maintenance hemodialysis treatment in the clinical centre in prishtina , for a period longer than 6 months .
patients were divided in two groups : 40 patients ( 22 female and 18 male ) with elevated crp levels over than 10 mg / l and 38 patients ( 18 female and 20 male ) with crp levels in the normal range .
40 healthy people ( 18 females and 22 males ) , were a control group .
crp was measured by the turbidimetric method based in combines of crp with specific antibody .
il-6 was measured with enzyme linked immunosorbent immunoassay ( elisa).diazyme s lipoprotein ( a ) assay is based on a latex enhanced immunoturbidimetric method.d - dimer was determined by the immuno - turbidimetric assay with monoclonal antibodies f(ab)2 fragments to the d - dimer epitope.fibrinogen was determined based on clause s method by measuring of ratio of fibrin formation.won willebrand factor ( vwf ) was measured by elisa and expressed as a percentage of normal value.serum albumin was determinate with bromocresol purple .
diazyme s lipoprotein ( a ) assay is based on a latex enhanced immunoturbidimetric method .
d - dimer was determined by the immuno - turbidimetric assay with monoclonal antibodies f(ab)2 fragments to the d - dimer epitope .
fibrinogen was determined based on clause s method by measuring of ratio of fibrin formation .
won willebrand factor ( vwf ) was measured by elisa and expressed as a percentage of normal value .
serum concentration of crp , il-6 , lp(a ) , fibrinogen , d - dimer and vwf in hemodialysis patients were significantly higher than in controls ( 24.40 15.20mg / l
vs 6.39 1.20 mg / l p<0.001 , 1.92 1.39 pg / ml vs 0.35 0.29 pg / ml , p < 0.001 ; 28.05 8.23 mg / dl vs 16.25 3.78 mg / dl , p<0.001 ; 3.44 0.93
g / l vs 2.55 0.77 g / l , p<0.01 ; 1.81 1.10 gfeu /ml vs 0.50 0.32 gfeu /ml , p<0.01 ; 152.9 40.8 % vs 85.6 20.5 % , p<0.001 ( table 1 ) , whereas serum albumin was significantly lower ( 32.10 6.05
g / l vs 40.50 3.90 g / l , p<0.001 ( table 1 ) .
biochemical parameters ( means and sd ) in hemodialysis patients and healthy controls serum concentration of il-6 , lp(a ) , fibrinogen , d - dimer , v wf , were significantly higher and serum albumin was significantly lower in patients with elevated crp levels than in patients with crp levels in normal range .
( 3.06 1.07 pg / ml vs 0.77 0.27 pg / ml , p<0.01 ; 32.80 7.37 mg / dl vs 23.30 6.0 mg / dl , p<0.001 ; 3.88 0.62
g / l vs 3.0 0.97 g / l , p<0.01 ; 2.28 1.19 gfeu /ml vs 1.35 0.75 gfeu /ml , p<0.01 ; 173.99 47.96 % vs 131.88 11.80 % , p<0.001 ; 27.81 5.25
g / l vs 36.39 2.94 g / l , p<0.001 ( table 2 ) . biochemical parameters ( means and sd ) in hemodialysis patients with elevated crp and crp in normal range significant correlation exists between crp and il-6 in patients with high crp levels .
crp and il-6 correlated positively with lp(a ) , ( r = 0.62 , p < 0.001 ; r=0.54 , p<0.001 ) , fibrinogen ( r = 0.63 ,
p < 0.001 ; r = 0.49 , p<0.01 ) , d dimer ( r = 0.72 , p<0.001 ; r = 0.55 , p<0.01 ) , vwf ( r=0.76 , p<0.01 ; r=0.63 , p<0.001 ) and negatively with serum albumin ( r = -0.80 , p<0.01 ; r = -0.60 , p<0.001 ) , in patients with elevated crp ( table 3 ) .
there was no correlation in patients with crp levels in normal range or in controls .
correlations of all parameters in haemodialysis patients with elevated crp ( crp > 10 mg / l )
chronic inflammation , predicts all - cause and cardiovascular mortality in hemodialysis patients in short- and long term studies ( 21 ) , in hemodialysis patients , serum il-6 level is known to be much higher than in general subjects , and is associated with mortality ( 7 ) .
were significantly higher in patients than in controls ( 24.40 mg / l vs 6.39 mg / l , p<0.001 ; 1.92 pg / ml vs 0.35 pg / ml , p < 0.001 ( table 1 ) and their positive correlation is significant ( r = 0.94 , p<0.001 ( table 3 ) .
pathways that might mediate the association between renal dysfunction and cardiovascular risk are the inflammatory and coagulation cascades .
activation of hemostasis is a common feature of uremia and its link with inflammation , has been reported ( 22 ) . in this study serum concentration of fibrinogen and d - dimer in patients
g / l vs 2.55 g / l , p<0.01 ; 1.81 gfeu /ml vs 0.50 gfeu /ml , p<0.01 ) than in controls .
atherosclerosis is initiated through endothelial abnormalities and elevated plasma concentration of fibrinogen and putative markers of endothelial dysfunction including vwf ( 23 ) .
we also found significantly higher levels of vwf in patients compared with controls ( 152.9 % vs 85.6% , p<0.001 ( table 1 ) . comparing the two groups , d - dimer fibrinogen and vwf levels were higher in patients with elevated crp than in patients with crp levels in normal range ( 2.28 g feu /ml vs 1.35 gfeu /ml
g / l vs 3.00 g / l , p<0.001 ; 173.99% vs 131.88% ; p<0.001 ( table 2 ) .
il-6 is demonstrated to increase the risk of atherosclerosis through metabolic endothelial and coagulant mechanisms , increasing the hepatic release of fibrinogen as well as having procoagulant effects of platelet ( 25 ) .
we also find positive correlation of il-6 with fibrinogen , ( r = 0.49 , p<0.001 ) , d dimer ( r = 0.55 , p<0.01 ) , and vwf ( r = 0.63 , p<0.001 ( table 3 ) in patients with high crp levels . based on results inflammatory response coexists with endothelial dysfunction . increased levels of lp ( a ) is an independent risk factor for coronary disease .
lp(a ) mean value was significantly higher in patients than in controls ( 28.05 mg / dl vs 16.25 mg / dl , p<0.001 ( table 1 ) , lp(a ) , occurs at high concentrations largely because of reduced clearance , or as a result of increased hepatic synthesis induced by an acute phase reaction or by proteinuria .
lp(a ) was significantly higher in patients exhibiting elevated crp than to those with crp in normal range , ( 32.80 mg / dl vs 23.30 mg / dl , p<0.001 ( table.2 ) .
a close relationship exist between lp(a ) levels and inflammation , as shown by correlations with crp and il-6 ( r = 0.62 , p < 0.001 ; r=0.54 , p<0.001 ( table 3 ) .
both end - stage renal disease and thromboembolic coronary events have been shown to be associated with the formation of dense fibrin clots resistant to fibrinolysis .
there are evidences that lp(a ) reduce clot permeability and susceptibility to lysis ( 17 ) . a significant positive correlations of lp(a )
were observed with d - dimer ( r=0.64 , p<0.001 ) , fibrinogen ( r = 0.61 , p<0.001 ) and vwf ( r = 0.74 , p<0.001 ( table 3 ) .
patients with high crp showed evidence of a higher degree of hyper coagulation than patients with crp levels in normal range .
thus , hemostatic abnormalities may be affected to other cardiovascular risk factors as lp(a ) . based in results
chronic hemodialysis may be a marker for systemic inflammation , which in turn is associated with high levels of lp(a ) and hypercoagulability .
il-6 is known to be associated with the severity of hypoalbuminemia in hemodialysis patients ( 18 ) .
we also find that crp and il-6 correlated negatively with serum albumin ( r = -0.80 , p<0.01 ; r = -0.60 , p<0.001 ( table 3 ) , which proved that hypoalbuminemia in hemodialysis patients is partially a consequence of inflammation .
inverse relationship existed also between serum albumin and lp(a ) in patients with elevated crp ( r = -0.58 , p<0.05 ( table 3 ) .
this correlation is a significant indicator for cardiovascular death of hemodialysis patients ( 26 ) .
albumin levels correlated negatively with d - dimer and vwf in patients with elevated crp ( r = -0.81 , p<0.001 ; r = -0.74 , p<0.01 ( table 3 ) .
the negative correlation of albumin with d- dimer and vwf confirm that hypoalbuminemia is associated with hypercoagulability .
a persistent inflammatory response and high levels of lp(a ) , in hemodialysis patients , may contribute to coagulation activation and increased cardiovascular risk .
these elevations were apparent even among patients with no evidence of clinical or subclinical cardiovascular disease . | background : inflammatory and procoagulant markers are potential mediators for the cardiovascular risk in hemodialysis patients . lipoprotein ( a ) [ lp(a ) ] , is another important risk factor with inflammatory and procoagulant effects.materials and methods : in 78 hemodialysis patients and 40 controls , c - reactive protein ( crp ) , interleukin-6 ( il-6 ) , lipoprotein ( a ) [ lp ( a ) ] , fibrinogen , d - dimer , von wilebrand factor ( vwf ) and serum albumin were determined.results:crp , il-6 , lp(a ) , fibrinogen , d - dimer and vwf , were significantly higher , and serum albumin was significantly lower in patients compared to controls ( 24.40 mg / l vs. 6.39 mg / l , p<0.001 ; 1.92 pg / ml vs. 0.35 pg / ml , 28.05 mg / dl vs.16.25 mg / dl , p<0.001 ; 3.44
g / l vs. 2.55 g / l , p<0.01 ; 1.81 gfeu /ml vs. 0.50 gfeu /ml , p<0.01 ; 152.9 % vs. 85.6 % , p<0.001 ; 32.1
g / l vs. 40.50 g / l , p<0.001 ) .
the patients were divided into two groups : 40 patients with crp levels over than 10 mg / l and 38 with crp levels in normal range .
these parameters showed significant differences between patients with elevated crp and patients with normal crp levels .
crp and il-6 correlated positively with lp(a ) , ( r = 0.62 , p < 0.001 ; r=0.54 , p<0.001 ) , fibrinogen , ( r = 0.63 , p
< 0.001 ; r = 0.49 , p<0.01 ) d dimer ( r = 0.72 , p<0.001 ; r = 0.55 , p<0.01 ) , vwf ( r = 0.76 , p<0.01 ; r = 0.63 , p<0.001 ) and negatively with serum albumin ( r = -0.80 , p<0.01 ; r = -0.60 , p<0.001 ) , in patients with elevated crp , but not in patients with normal crp levels and controls.conclusion:according to the results hemodialysis patients with increased inflammatory markers , have the elevated lp(a ) and procoagulant markers and the greater risk for atherosclerotic cardiovascular disease . |
myocardial infarction ( mi ) and stroke are the leading causes of cardiovascular ( cvd ) morbidity and mortality worldwide , especially in low- and middle - income countries ( lmics ) where 80% of the total cvd burden occurs .
cvd death rates , already higher in poorer populations , are also rising , as the death rates in many wealthy countries are waning [ 13 ] . in vietnam , stroke is the leading cause of death followed by heart disease , although mortality from coronary heart disease has recently risen .
findings from interheart and interstroke studies suggest that a few traditional modifiable risk factors could explain over 90% of the population attributable risk of both mi and stroke .
these include hypertension , abnormal lipids , tobacco use , obesity , diabetes mellitus , diets with low intakes of fruits and vegetables , physical inactivity , excessive alcohol intake , and psychosocial factors .
modification of currently known risk factors has the potential to prevent most premature cases of both mi and stroke worldwide , providing that there are differences in the relative importance of each risk factor for stroke or mi between men and women and across different geographic regions or ethnic groups [ 610 ] , due to variations in risk factor profile , cvd burden , and socioeconomic cultural circumstances . in offering an evidence - based context for policy planners and health education programmes in a low - resource setting like vietnam ,
it is important to quantify the proportion of the population at high overall risk of cvd in order to match this with availability of resources . in reality ,
a substantial proportion of the population carry individual clusters of several risk factors , which demonstrates the need for comprehensive population - wide strategies and approaches .
when treatment decisions are to be made concerning individual clinical interventions , it is clear that a smaller proportion of people are at highest risk due to individual clustering of risk factors , including age and sex , and need to be identified for rational resource and health system planning .
this study aims to describe the prevalence of each important cvd risk factor as well as providing a profile of the individual clustering of major cvd risk factors in a representative sample of the adult population of vietnam , highlighting the differences between men and women .
the study also aims to estimate the prevalence of people having high overall 10-year cvd risks using the framingham general cardiovascular risk score
. these findings will be important for optimizing the selection of risk - factor targets for population - based or individual - based programmes to prevent and reduce the burden of cardiovascular diseases in the studied communities as well as in extrapolations to the population of vietnam .
a cross - sectional survey was conducted in march and august 2009 , using a multistage sampling strategy to identify the prevalence of major cardiovascular risk factors including lipidaemia profile in thai binh ( a rural province ) and hanoi ( a urban province ) of vietnam .
this survey followed the framework of the national survey on hypertension , in which hanoi represented city areas and thai binh represented lowland areas , but the blood tests were only taken from a 1-in-5 sample of participants in the city area for fasting glucosaemia and lipidaemia profile due to limited financial resources . similarly to the previous national survey , a representative sample of the adult population ( 25 years old ) from both hanoi and thai binh provinces was randomly selected from 24 primary sampling units ( communes : 110 person sample per commune ) , following 3 communes per district and 4 districts per province .
data were collected at local health stations in the selected communes by trained and qualified surveyors using a questionnaire which included personal medical history of any relevant chronic diseases , demographic background ( age , sex , residential area , occupation , and education level ) and self - reported behavioural risk factors ( smoking history , alcohol consumption , dietary salt habit , daily fruit and vegetable consumption , level of physical activities , level of stress ) . in addition , all participants were requested to fast overnight in order to have an oral glucose tolerance ( ogt ) test and a blood sample for lipid profiles ( including total cholesterol , triglyceride , low - density lipoprotein cholesterol ldl - c and high - density lipoprotein hdl - c ) .
blood samples were collected , stored , and analysed by specialists from the department of biochemistry , bach mai hospital hanoi , vietnam .
people with no history of diabetes were asked to perform ogt test loaded with 75 g anhydrous glucose .
portable glucometer devices from terumo with corresponding strips were used to measure glucosaemia pretest and 2 h after ogt test . among 2,640 invited subjects , 2,306 participated in the survey , giving an overall response rate of 87.3% ( 99.8% in thai binh province and 75.0% in hanoi province ) .
a further 176 ( 7.6% ) participants were excluded from analysis due to pregnancy status or missing important information or blood test results .
occupational status was classified into three groups : government staff , manual workers ( farmers , building workers ) , and other occupations ( housewives , handicraft makers , jobless , disabled ) . educational level , which was determined by years of schooling and level at graduation , was classified into 2 groups : incomplete secondary schooling ( 9 years of education ) and higher ( > 9 years of education including graduation from high school or higher ) .
residential area , which was divided into urban and rural , was identified on an administrative basis for each commune within each province .
people who smoked tobacco products such as cigarettes , cigars , or pipes over the previous month were classified as current smokers .
people who took more than 2 standard units of drink per day ( women ) or more than 3 per day ( men ) were defined as having an excessive alcohol intake .
people who ate less than five servings of fruit and/or vegetables on average per day were defined as having a diet with low fruit and vegetable consumption .
people who preferred daily foods that contained more salt than the similar foods ordered by other adult members in the family or people around them were classified as having salty diets .
energy requirement in metabolic equivalents ( mets ) for each individual was estimated based on details of duration and type of all self - reported physical activities in a typical week .
people with total physical activity less than 3000 mets minutes per week were classified as physically inactive .
similarly to the interheart study , psychosocial stress was assessed and semiquantitated by several simple questions to evaluate whether the participants had any stress at work or at home , any financial stress , any major life events ( such as marital separation or divorce , loss of crop or job , major intrafamily conflict , death , illness of a close family member / spouse , etc . ) or any other major stress in the past year at different levels ( none , mild , moderate , and severe ) .
blood pressure ( bp ) was measured at least twice , at least two minutes apart in a resting and sitting position using an automatic digital sphygmomanometer ( omron healthcare inc . ,
bannockburn , illinois , usa ) , with an appropriate sized cuff , following a similar standardized protocol as undertaken in the national survey .
a third measurement was performed if the difference between the first two measurements was more than 10 mmhg .
hypertension was defined as an average systolic bp ( sbp ) 140 mmhg , and/or average diastolic bp ( dbp ) 90 mmhg , and/or self - reported current treatment with antihypertensive medications [ 1720 ] .
body weight , height , waist and hip circumference were measured by trained and qualified surveyors twice strictly following the standardised protocol previously described elsewhere .
body mass index ( bmi ) was calculated as weight ( kg ) divided by height squared ( m ) .
overweight was defined as bmi 23 and obesity was defined as bmi 25 or having central obesity ( bmi 23 with waist circumference either 90 cm in men or 80 cm in women ) , both mentioned criteria having been specified for south - asian populations by who regional office for western pacific ( wpro ) .
dyslipidaemia was defined as self - reported current treatment with cholesterol - lowering medications and/or having one or more of the following , based on blood test results : total cholesterol 5.17 mmol / l ; hdl - c < 1.03 mmol / l ; ldl - c 3.36 mmol / l ; triglyceride 1.7
mmol / l , as recommended by national cholesterol education program ( ncep ) expert panel on detection , evaluation , and treatment of high blood cholesterol in adults ( atp iii ) guidelines .
diabetes was defined as fasting glucose 7.0 mmol / l and/or 2 h after ogtt glucose 11.1
mmol / l and/or self - reported as currently taking any diabetes medication , as recommended by american diabetes association ( ada ) guidelines [ 2326 ] .
the prevalence of each risk factor and their clustering within individuals were calculated for men and women , stratified by age group to identify the differences in cvd risk factor patterns between women and men .
details of age distribution by sex in urban and rural areas of selected districts in hanoi and thai binh provinces from vietnam population and housing census in 2009 were used to weight and age - standardise the above prevalences for the studied population as well as for extrapolation to the whole population .
these cvd risk factors were divided into two groups : metabolic factors ( including hypertension , abnormal lipids , obesity , diabetes mellitus ) and behavioural factors ( including tobacco use , excessive alcohol intake , unhealthy diet , physical inactivity , and psychosocial factors ) .
unhealthy diet was determined from both self - reported diet - related risk factors ( either high salt or low fruit and vegetable consumption ) .
people who had 2/4 metabolic factors , 2/5 behavioural factors , or 4/9 of all mentioned risk factors were considered to have individual clusters of respective risk factors .
framingham general cardiovascular risk scores , which apply to individuals from 30 to 74 years old without baseline cvd , were used to estimate the overall 10-year risk of developing coronary heart disease ( myocardial infarction , coronary death ) and other important potential adverse cardiac events ( stroke , heart failure ) in the community .
the score incorporated the following variables : age , sex , tobacco use , treated and untreated systolic blood pressure , diabetes , and lipid profile ( total cholesterol , hdl - cholesterol ) or bmi ( replacing lipids in a simpler model ) .
people who had overall 10-year cardiovascular risk 20% were classified as having a high overall cvd risk .
both descriptive and analytical statistical analyses were carried out using stata 11 software ( stata corporation , texas , usa ) . means with standard errors and proportions with 95% confidence intervals ( cis ) for variables of interest were calculated .
multivariable logistic regression analyses were performed to examine the association between social characteristics and clustering of risk factors and their associated odds ratios ( ors ) and 95% cis were presented , separately for women and men .
a p value < 0.05 ( two tailed ) was considered to represent statistical significance .
this study protocol was approved by both scientific ethical committees in biomedical research at bach mai hospital , hanoi , vietnam and at the international medical centre of japan ( imcj ) hospital , tokyo , japan .
all human subjects in the study were asked for their consent before collection of data and venous blood , and all had complete rights to withdraw from the study at any time without any threat or disadvantage .
any participants with high blood pressure or other disorders were referred to appropriate facilities for further investigation and treatment .
after excluding 176 records with missing data , a total of 2,130 subjects were analysed , of which 1,345 ( 63.2% ) were women and 830 ( 36.5% ) were men .
the average age for women was 52.0 years and for men 53.7 years ; there was no difference in age group structure .
the sex ratio in our study population was quite similar to the results from the previous national survey on hypertension , in which the study sample was also randomly selected from to the entire list of current inhabitants at the study regions in multistage sampling .
both our study and the previous national survey probably reflected the contemporary sex ratio of the local remaining adult population , which obviously excluded a substantial number of people ( mostly male ) who temporarily out - migrated to earn money for their families .
table 1 shows the characteristics of the studied population , including social factors , biological and self - reported behavioural factors .
compared to biological characteristics among women , men had significantly higher weight , waist circumference , waist hip ratio , blood pressure ( both systolic and diastolic ) , ldl - cholesterol , triglyceride , and fasting glucosaemia but lower hdl - cholesterol .
there was no difference in bmi and total cholesterol between the sexes . in terms of behavioural risk factors , significantly higher proportions of men were currently smoking ( p < 0.01 ) , having excessive alcohol intake ( p < 0.01 ) , unhealthy diet with low consumption of fruit / vegetable or high salt diets ( p < 0.05 ) , but there were no differences in the proportions of physical inactivity or experience of stress in men compared to women ( table 1 ) .
the prevalence of unhealthy diets was lower in women ( 53% ) than in men ( 60% ) .
table 2 shows the prevalence of each cvd risk factor and prevalence for having clusters of cvd risk factors , stratified by age group and sex , after weighting with the national age distribution in 2009 in order to reflect the current profile of cvd risk factors in the studied population of vietnam .
overall , the prevalence of all cvd risk factors , except for physical inactivity and experiencing stress , was considerably higher in men than in women . figures 1(a ) and 1(b ) show the different trends of clustered cvd risk factors between men and women : the average number of cvd metabolic risk factors in women tended to increase more steeply with age and exceed the trend in men over 55 years of age , while the average number of cvd behavioural risk factors in men tended to decrease with age . both versions of framingham general cvd risk score , one using lipid profiles and the other using bmi , were applied to calculate the overall risk of cardiovascular events within 10 years . within the studied population ,
the risks estimated using bmi were higher , around 10% in women and 20% in men , than the estimates using lipid profiles .
the prevalence for having an overall risk greater than 15% and 20% , respectively , is shown in table 3 .
the prevalence of having high overall cvd risk sharply increased with age , exceeding 10% after the age of 45 years in men and after 55 years in women .
multivariable logistic regression models were constructed to analyse the associations between having clusters of cvd risk factor and age , residence , occupation , and educational level ( table 4 ) .
the models showed that having clusters of metabolic risk factors was less common at younger ages , among people living in rural areas or doing manual work for both sexes , while having cluster of behavioural risks was more common in women with higher educational levels and in men with manual jobs .
this could be explained by the higher proportion of excessive alcohol intake and physical inactivity in women having higher education or higher proportions of smoking , self - reported unhealthy diet and physical activity in men having manual jobs , while there was no difference among the remaining behavioural factors .
findings from our study showed that major modifiable cvd risk factors were common and often individually clustered in the studied adult population of vietnam , increasing with age and having different patterns between sexes .
we acknowledge that the cross - sectional design might introduce some misclassification due to self - reported information and the data might not truly reflect the time and context - bound aspects of cvd risk factor patterns .
in addition , some factors such as experiencing stress were challenging to measure and there was no clear evidence on how to address stress in primary prevention . using the same frameworks as the previous national survey and implementing in two similar provinces ( hanoi and thai binh ) , both glucosaemia and lipidaemia disorders were extensively investigated in this study in order to fill gaps in our understanding of major metabolic cvd risk factors in the vietnamese population , although the data were only available from two provinces rather than the eight provinces in the national surveys , due to limited financial resources .
bearing in mind these limitations , the study tried to obtain a snapshot across a panorama of nine changeable risk factors , which accounted for over 90% risk of cardiovascular events [ 6 , 7 ] , then extrapolating and proceeding to image the contemporary population burden of cvd risk factors both as single factors and within - individual clusters .
hypertension , smoking , and excessive alcohol intake are considered as the most prominent risk factors for chronic and cardiovascular diseases [ 13 , 29 ] .
estimates from our study that 26.4% of adults ( 25 years old ) suffered from hypertension would extrapolate to 12.5 million people nationally , while only 26.7% ( equivalent to 3.3 million ) of these hypertensives were treated .
however our results showed that lipid abnormalities ( 60% in the sample , extrapolating to 28.5 million people ) and unhealthy diet ( 54.6% , 25.9 million ) were the most common in both sexes , while smoking and excessive alcohol intake were prominent only in men .
future intervention programmes to cover newly emerging cvd risk factors such as unhealthy diets or dyslipidaemia measured by changes in cholesterol levels may be important in countries such as vietnam where changes in food consumption patterns are occurring at a rapid pace .
although our data from one cross - sectional survey could not differentiate the sequence in which metabolic risk factors developed , the increasing trend with age for each risk factor was consistent with suggestions that high adiposity and cholesterol often preceded the development of hypertension and diabetes from young adulthood to middle age in 20-year followup of cardia study [ 30 , 31 ] , and consistent with causal web of lifestyle risk factors for chronic disease prevention .
quite a few studies showed the substantial proportion of cvd risk factors clustered among individuals in the population although the variations could be influenced by various differences in geographical , socioeconomic characteristics , age structure , time of study ( seasonal variations ) , cut - off points for high risk classification , exclusion or inclusion criteria for cvd risk factors [ 10 , 3335 ] .
projected from our study , 20.4% adults aged 25 years and above in the population had clusters ( 4/9 ) of all major cvd risk factors .
cvd incidence and mortality increase as quality of life decreases progressively with the number of cvd risk factors [ 3639 ] . in our study , both systolic and diastolic bp increased with the number of risk factors in both sexes
. the overall cvd 10-year risk also increased with the number of cvd risk factors in both sexes ( figure 2 ) . in reality , blood pressure control worsened as the number of cvd risk factors increased even with multiple drug therapies [ 4143 ] ; therefore , decisions about hypertension management should always consider the presence of other cvd risk factors rather than bp level alone .
cvd risk was influenced in a cumulative fashion by socioeconomic , behavioural , and biological factors acting throughout the life course , in which people with lower social economic status would be more susceptible and likely to have cvd risk factors , leading to cardiovascular events later in life [ 4550 ] .
influences on metabolic disorders from lifestyle and culture habits are even stronger than those from genetic factors .
our results suggested the importance of urban living conditions where people had higher prevalence of metabolic disorders after adjusting for age and other social factors , in accordance with results from other studies [ 8 , 33 , 52 ] .
a number of multivariate risk models [ 12 , 22 , 5357 ] have been developed to integrate individual factors in apparently healthy , asymptomatic individuals for estimating the risk of specific cardiovascular events such as coronary heart disease ( fatal or nonfatal ) and stroke over a certain period of time .
theoretically , the estimated risk of important cardiovascular events would be very useful both for patient education ( e.g. , motivating patients to adhere to risk - reduction therapies ) and for clinical practice ( identification of high - risk patients who deserved immediate care and modification of the intensity of management strategies ) .
however , the complexity of the equation , time and context - bound results , confused assessment of outcome or risk factors , lack of some variables in low - resource settings , regular need for validation [ 58 , 59 ] , regulatory constraints , and the nature of the physician - patient relationship all are hidden barriers to the routine use of cvd risk scores in daily practice , especially in primary care where blood tests were not available in low - resource settings .
in addition , the overall risk stratification approach is likely to counter the established clinical practice in most lmics that tend to focus on risk - factor thresholds , even though risk - based care is more effective and cost - effective . in this study ,
the framingham general cardiovascular 10-year risk scores were applied to estimate potential adverse cardiovascular events individually and then totally in the studied population , including both stroke and coronary heart disease outcomes , bearing in mind that these scores could be overestimates or underestimates of the event risks in the population of vietnam , where there has been no validation or calibration studies so far .
we acknowledge that the equation only covered a few cvd risk factors , and their impacts on predicted outcomes were assumed to be linear for all variables and similar to the original framingham population , which might not be true in the context of transition and development in contemporary vietnam .
bearing in mind these limitations , an estimate of 10% in the studied population ( extrapolated to 3.7 million people in the vietnamese population ) aged from 30 to 74 ( 4.6% in women and 20.4% in men ) had an overall cvd 10-year risk 20% ; the more risk factors , the higher the overall cvd risk .
the results also showed the homogeneity between two versions of the framingham score using either bmi or lipid profiles ( table 3 ) and suggested that the simplified score version using bmi has potential advantage for wider application in low - resource settings , obviating the need for blood tests for lipid profiles in prioritising available strategies or approaches to intervention against cvd risk factors in primary care .
absolute risk charts using similar predictors ( age , sex , smoking status , sbp , bmi , and/or diabetes ) were a feasible and replaceable solution for individuals in daily practice but were not sensitive enough to capture small changes in overall risk resulting from interventions and for summarising the benefits for heterogeneous populations with diverse cvd risk patterns . however , further cohort studies should be used to calibrate these equations in order to improve the local predictability of future cardiac events .
based on individual calculated overall risk profiles , we estimated the average overall risk at the population level and predicted potential adverse cardiovascular events over 10 years .
our extrapolations revealed that the average overall risk for any cardiovascular event over 10 years for whole population aged from 30 to 74 years was 8.89.4% , in other words , 3.33.5 million cvd events could happen over 10 years ( figure 3 ) .
it has been estimated that just three cost - effective interventions , tobacco control , salt reduction , and a multidrug clinical service to treat individuals at high overall risk of cardiovascular disease would avert deaths in vietnam [ 61 , 62 ] .
recently , other interventions , though less cost - effective and feasible , have been implemented to tackle unhealthy diets , physical inactivity , obesity , focusing more on bmi - mediated distal risk factors as well as policy - level solutions to create favourable environments for implementing effective strategies in primary care .
based on some assumptions about the effectiveness of healthy lifestyle interventions [ 6569 ] or drug therapy to manage blood pressure or dyslipidaemia , we tried to calculate the absolute risk reduction ( arr ) of average overall cvd risk in the population and predict the reduction of potential adverse cardiovascular events , which could arise as benefits from various scenarios of risk factor intervention ( figure 3 ) .
previous studies showed that hypertension is a major public health problem in vietnam [ 13 , 29 ] , requiring a lot of effort to detect and deliver appropriate management , constituting a high priority in the existing system of primary care .
however , our extrapolated estimation suggested that treatment of a cvd risk factor alone ( such as hypertension ) without taking into consideration other modifiable cvd risk factors ( such as smoking , unhealthy diet ) would not be an efficient approach for achieving a high general health impact .
a population strategy to reduce tobacco consumption in men and halt the rise in women should be the first priority .
the high level of unhealthy diet and potential benefit from interventions suggests a population - wide strategy though the mass media aimed at reducing salt content in food is the next strategy . the high - risk individual approach would benefit the entire population more than only approaching hypertensives .
if there were not enough resources to assess overall cvd risk on a wide scale , especially where expensive blood tests are required , simplified equations using age , sex , tobacco use , blood pressure levels , and bmi could be used to estimate the overall risk . in addition ,
where resources allow , a combined community approach ( mostly by healthy lifestyle promotion ) and individual approaches using simpler and more feasible measurements to identify people at high risk could be employed .
in conclusion , nine major cvd risk factors , often clustered within individuals , were common in the adult population of vietnam with differences noted between sex and age groups , testifying to the need for inclusion of age and sex in any risk prediction models .
tackling any single risk factor alone without considering other modifiable cvd risk factors is not an efficient or sustainable approach . combination of population and individual approaches are required to reduce the burden of cvd risk factors and maximise the protective effects for the whole community .
modification and calibration of an existing score for the vietnamese population , for identifying individuals at high risk of cvd , is a priority . | background . data on cardiovascular disease risk factors ( cvdrfs ) in vietnam are limited .
this study explores the prevalence of each cvdrf and how they cluster to evaluate cvdrf burdens and potential prevention strategies .
methods . a cross - sectional survey in 2009 ( 2,130 adults ) was done to collect data on behavioural cvdrf , anthropometry and blood pressure , lipidaemia profiles , and oral glucose tolerance tests . four
metabolic cvdrfs ( hypertension , dyslipidaemia , diabetes , and obesity ) and five behavioural cvdrfs ( smoking , excessive alcohol intake , unhealthy diet , physical inactivity , and stress ) were analysed to identify their prevalence , cluster patterns , and social predictors .
framingham scores were applied to estimate the global 10-year cvd risks and potential benefits of cvd prevention strategies .
results .
the age - standardised prevalence of having at least 2/4 metabolic , 2/5 behavioural , or 4/9 major cvdrf was 28% , 27% , 13% in women and 32% , 62% , 34% in men .
within - individual clustering of metabolic factors was more common among older women and in urban areas .
high overall cvd risk ( 20% over 10 years ) identified 20% of men and 5% of women especially at higher ages who had coexisting cvdrf .
conclusion .
multiple cvdrfs were common in vietnamese adults with different clustering patterns across sex / age groups .
tackling any single risk factor would not be efficient . |
herpesviruses are major pathogens associated with a number of diseases both in man and animals .
since herpesviruses have large genomes , between 120 kbp230 kbp in size , the manipulation of the viral genomes to identify the molecular determinants and mechanisms of pathogenesis is difficult .
however , the use of bacterial artificial chromosome ( bac ) as vectors for cloning the large dna virus genomes as a single - copy mini - f plasmid has opened new avenues for carrying out reverse genetics approaches for understanding herpesvirus gene functions .
marek 's disease virus ( mdv ) , a member of the genus mardivirus , is a highly contagious alphaherpesvirus that induces marek 's disease ( md ) , characterised predominantly by a rapid - onset t - cell lymphoma in poultry .
bac technology was first applied to clone the genome of an attenuated serotype 1 mdv strain 584ap80c . since then
, the genomes of a number of virulent and attenuated mardiviruses have been cloned as infectious bac clones [ 411 ] and used to identify the determinants of virulence as well as for expression of foreign genes [ 1214 ] .
md is controlled primarily by the widespread use of a number of live attenuated vaccines since the 1970s .
these include the antigenically related herpesvirus of turkey ( hvt ) , mdv-2 strain sb-1 , as well as the widely used cvi988 ( rispens ) strain .
although vaccines have been generally very successful in reducing the losses from the disease , vaccination strategy has not been very effective in preventing the evolution of viruses towards greater virulence [ 1618 ] .
this has necessitated the periodic introduction of different generations of vaccines to keep up with continuing increase in virulence of the mdv and a number of different pathotypes classified as vmdv , vvmdv , and vv+mdv pathotypes have been isolated [ 15 , 19 ] .
even though the molecular determinants associated with the increasing virulence of these pathotypes are yet to be identified , the genome sequence of these viral pathotypes has indicated changes in parts of their genomes [ 20 , 21 ] .
although the analysis of the sequence changes are helpful , functional studies with mutant viruses are required to identify the determinants of altered virulence of these mdv pathotypes .
cloning of the genomes of virulent mdv pathotypes as infectious bac can facilitate the application of reverse genetics approaches to generate mutant viruses and to identify the functional determinants associated with the altered pathological characteristics of these viruses .
mdv strain c12/130 was isolated from a field outbreak of hvt - vaccinated broilers in 1991 from the united kingdom .
the disease it produces has an unusually severe cytolytic phase , with enlargement of spleen , regression of the primary lymphoid organs , bursa of fabricius and thymus , and very late tumours [ 22 , 23 ] .
two similar strains were isolated in europe at the time , mr36 and mr48 ; these strains produced high early mortality and destruction of the lymphoid tissues .
monocytosis is a feature of the c12/130 strain , and neurological disease has also been associated with mononuclear cell infiltration of the meninges from 6 to10 days post infection .
birds infected with c12/130 strain have increased cell death of the infected b - cells and macrophages during the acute cytolytic phase .
this virus shares characteristics with vv+mdv as described by witter , but can not be classified as such due to the lack of formal pathotyping studies . in the current study
, we report on the cloning of the hypervirulent uk mdv strain c12/130 to elucidate some of its unique biological properties .
wild - type virus populations are often considered to exist as a collection of individual viruses that make up the quasispecies [ 21 , 26 ] , and we have previously shown that the cloning of the cvi988 ( rispens ) virus as bac clones has enabled the identification of individual clones with molecular differences in their genomes .
based on these observations , we hypothesised that the wild - type c12/130 virus population is comprised of a pool of viruses , and cloning the genomes of these viruses as bac clones would allow us to examine the behaviour of individual viruses in the pool .
this paper describes the in vitro and in vivo characteristics of viruses derived from five individual bac clones of c12/130 virus .
primary or secondary chicken embryo fibroblasts ( cefs ) maintained in medium 199 ( gibco brl ) , supplemented with 10% tryptose phosphate broth and 5% foetal calf serum were used to grow up the virus stocks .
c12/130 virus isolated from splenocytes prepared from infected rhode island red ( rir ) chicks at 6 days postinfection ( dpi ) were used as the source of dna for the generation of the recombinant bac clones .
the procedures for the construction of the bac clones were carried out essentially as described [ 2729 ] .
briefly , the pds - pha1 vector , which contains the mini - f plasmid flanked by 2.1 and 3.0 kbp homologous regions surrounding the us2 gene of mdv-1 , was used for the construction of the bac clones .
the c12/130 viral dna for the generation of bac was extracted from infected cefs using standard phenol chloroform extraction methods .
primary cefs ( seeded at 1.3 10 cells per well ) in a six well plate were used for the cotransfection of the c12/130 virus - infected dna and the pds - pha1 vector dna using the calcium phosphate precipitation method .
approximately 1.25 g per well of the pds - pha1 dna was cotransfected with varying volumes ( 1 l , 2.5 l and 5 l ) of c12/130 dna .
after cotransfection of the c12 - 130 dna with the pdsphai vector , the cells were passaged four times in selection medium containing mycophenolic acid , xanthine , and hypoxanthine .
genomic dna was then extracted from the selected cells and electroporated into e coli dh10b cells .
dna extracts from chloramphenicol - resistant colonies were further analysed by restriction digestion , followed by transfection of 1 g of dna into cefs , and monitored for viral infectivity . of several clones
tested , five clones that produced mdv plaques on cefs after transfection of the bac dna were used to prepare viral stocks following two further passages .
the integrity of the recombinant bac constructs was examined by molecular analyses of the dna from the individual c12/130 bac clones by agarose gel electrophoresis of dna samples digested with bamhi , ecori , and hindiii .
dna samples from wild - type c12/130 virus , the five recombinant c12/130 bac clones , and the previously reported prb-1b5 were also analysed by southern hybridisation using digoxigenin - labelled probes ( roche diagnostics , east sussex , united kingdom ) .
the dig - labelled probes specific for gpt and meq genes were prepared by pcr using gpt probes ( 5-atgagcgaaaaatacatcgtc-3 and 5-ttagcgaccggagattggcgg-3 ) and the meq probes ( 5-gcactctagaggtgtaaagagatgtctcag-3 and
all chickens used in the experiments were specific pathogen free ( spf ) , free of maternal antibodies to mdv , and hatched and reared in the experimental animal house with hepa filtered rooms , one group per room .
all the experiments were carried out under british home office regulations , by trained staff holding a home office personal licence for the various procedures .
birds were killed by a schedule i method once the clinical end - point defined by home office regulations was reached .
experiment 1 was designed to examine the genetic susceptibility of different lines of chickens to infection with wild - type c12/130 virus .
the five lines of chickens used in this experiment included the congenic inbred line n ( mhc b ) , line p ( mhc b ) , line 6 , line 7 ( mhc b ) , and the outbred rhode island red ( rir ) line .
ten birds of each line were infected with 1,000 plaque forming units ( pfu ) of wild - type c12/130 virus stocks via the intra - abdominal route at one day of age and observed for 60 days for the development of clinical signs .
birds that developed clinical signs during or at the end of the experiment were examined post mortem for gross or histopathological lesions .
experiment 2 was designed to examine the differences between the recombinant viruses reconstituted from the individual bac clones in their ability to induce early cytolytic disease .
the experiment was carried out in one - day - old outbred rir chickens inoculated with 1,000 pfu of wild - type c12/130 , and the reconstituted recombinant viruses as described in experiment 1 , 12 per group , each was housed in separate rooms with two sentinels .
the cytolytic phase of infection was allowed to proceed , and the birds were observed for 12 days .
all the birds that developed clinical signs and reached the clinical endpoint ( birds that appeared distressed , that is , off their legs , not eating or drinking , with paralysis , twisted neck , or visible tumours ) were killed , and the survival rates calculated from the incidence of md based on gross or histopathological lesions with graphpad prism ( version 5 ) using the product limit method of kaplan and meier , and curves were compared using the log rank test , equivalent to the mantel - cox test .
tissues were taken from freshly killed birds and fixed in 4% paraformaldehyde for two hours then transferred to pbs at 4c .
tissue sections were cut at 70 m using a vt1000s vibrating microtome ( leica microsystems , milton keynes , united kingdom ) .
sections were permeabilised in 0.1% triton x100 ( sigma ) for one hour at room temperature and blocked overnight in blocking buffer ( pbs supplemented with 0.05% sodium azide , 0.5% bovine serum albumin , and pbs / bsa ) .
sections were incubated with primary monoclonal antibody bd1 recognising mdv - encoded protein pp38 and species - specific alexa fluor 568-conjugated secondary antibodies .
the sections were washed in pbs and cellular nuclei stained with dapi ( 1 : 5,000 ) for 40 minutes . the sections were mounted onto glass slides using vectashield mounting medium , and coverslips were sealed with nail varnish before visualisation by confocal microscopy ( leica microsystems ) .
cotransfection of cefs with wild - type c12/130 viral dna and the pds - pha1 dna and subsequent growth in the presence of selection medium showed evidence of viral infection , demonstrating the growth of recombinant viruses .
electroporation of the dna extracted from the cefs into e. coli dh10b cells generated a number of chloramphenicol - resistant colonies .
the ability of the high molecular weight dna prepared from these cultures to reconstitute infectious virus was tested by dna transfection into cefs .
these experiments showed that five of the dna extracts were able to produce infectious virus 3 - 4 days after transfection , demonstrating the reconstitution of the virus from the transfected dna .
the size and morphology of the plaques produced by the wild - type and the recombinant c12/130 were indistinguishable ( not shown ) .
these infectious bac clones were designated pc12/130 - 3 , -5 , -8 , -10 , and -15 , respectively .
pulse field gel electrophoresis of the bamhi , ecori , and hindiii digested dna samples from these clones demonstrated a pattern similar to that of the prb-1b5 clone ( data not shown ) , demonstrating that the bac clones did not have any major deletions or genomic rearrangements .
southern blot hybridization of the ecori - digested dna of these clones with the gpt probe demonstrated a single major hybridizing band ( ~1.7 kb ) in all the pc12/130 clones , at an identical position to that in the prb-1b5 ( figure 1(a ) ) .
demonstration of identical bands in the dna samples from the reconstituted viruses of two of the bac clones , that is , pc12/130 - 10 and pc12/130 - 15 , showed that the mini - f plasmid is carried in the genome of the reconstituted viruses .
the specificity of the probe was confirmed by the absence of signals in the dna prepared from the wild - type c12/130 virus .
hybridization of the same blot with the meq probe detected the meq gene ( ~2.2 kb ) in all the bac clones and the wild - type and reconstituted c12/130 viruses ( figure 1(b ) ) .
one of the distinguishing features of some of the recent hypervirulent mdv strains , such as the c12/130 strain , is the ability to induce rapid - onset cytolytic disease characterized by marked atrophy of the lymphoid organs and high mortality .
previous studies have also shown that birds infected with c12/130 virus developed marked monocytosis and infiltration into the brain [ 3436 ] , possibly accounting for the high levels of mortality .
interestingly , the involvement of the brain has been shown to be associated with a number of the hypervirulent strains [ 37 , 38 ] .
the association between occurrences of neurological syndromes and the increasing virulence of mdv strains has led to the demonstration that neuropathotyping can be used to classify the virulence of mdv pathotypes . in the present study
, we first examined whether the wild - type c12/130 virus did indeed induce acute cytolytic disease and neurological symptoms and whether the genetic background of the chickens affected the susceptibility to the disease .
the incidence of the disease , calculated from the percent survival during the 60-day experimental period , showed that the outbred rir birds were highly susceptible to the disease , with more than 90 per cent of the birds developing acute cytolytic disease within the first 10 days after infection ( figure 2(a ) ) .
the study of genetically susceptible line p and line 7 demonstrated around 40% incidence of md during the same period , with the latter showing high incidence of the disease towards the end of the experimental period .
the two genetically resistant lines n and 6 displayed only mild levels of md , demonstrating that the genetic resistance mechanisms of these lines also function against hypervirulent strains .
having demonstrated that the rir chicks are highly susceptible to the early cytolytic disease induced by c12/130 virus , we wanted to examine whether the recombinant c12/130 viruses reconstituted from the individual infectious bac clones induced cytolytic disease and neurological lesions akin to the wild - type virus from which they were derived .
for this , we carried out experimental infection of highly susceptible one - day - old rir chickens with c12/130 viruses reconstituted from five infectious bac clones together with the wild - type virus .
groups of birds infected with 1,000 pfu of each of the viruses were observed during the 12-day experimental period for the development of cytolytic disease .
as demonstrated in the previous experiment , more than 90 per cent of the birds infected with the wild - type c12/130 virus developed the early cytolytic disease during this period ( figure 2(b ) ) .
however , viruses reconstituted from the five individual bac clones presented a range of differences in early cytolytic disease development .
c12/130 virus reconstituted from the bac clone 10 induced the highest level of the disease in more than 50 per cent of the birds , with viruses from the clones -3 , -5 , and -8 developing slightly lower levels of the disease .
in contrast , virus derived from the pc12/130 - 15 clone did not produce any disease during the experimental period ( figure 2(b ) ) .
the clinical signs of birds developing acute cytolytic disease were indistinguishable between wild - type and reconstituted viruses and included ruffled feathers , crouched appearance , and neurological signs . as expected , none of the birds had any evidence of tumors although varying levels of atrophy of the lymphoid organs thymus and bursa of fabricius were visible in many of the birds that developed the cytolytic disease .
of the sentinel birds , blood samples were examined by qpcr from 14 days after infection of their cohorts ; only those housed with the wild - type infected birds became infected with md ( data not shown ) .
previously , we have reported the detection of viral antigens in brain lesions of birds infected with c121/30 virus .
similar reports on the detection of virus - infected cells have also been published in birds infected with vv+mdv strains such as 648a , suggesting that the infiltration of virus - infected cells into the brain is a characteristic feature of hypervirulent mdv strains .
we wanted to examine whether the c12/130 viruses reconstituted from the bac clones would infiltrate the brain of birds and express viral antigens .
for this , we examined the brain samples from birds infected with the wild - type c12/130 or the viruses reconstituted from the pc12/130 - 10 and pc12/130 - 15 clones for viral antigen pp38 by immunofluorescence staining using the specific antibody bd1 .
viral antigen pp38 could be detected in the brain tissues of birds infected with the wild - type as well as the two bac - derived viruses ( figure 3 ) .
interestingly , pp38 was also detected in the brain of birds infected with c12/130 - 15 virus although they did not develop any early cytolytic disease .
these results suggested that the infiltration of infected cells is not necessarily associated with the acute cytolytic disease although we did not attempt to quantitate the levels of the infiltration of infected cells into the brain .
our study presents several interesting highlights . at the outset , this is the first report on the cloning of the full - length genome of a hypervirulent european mdv isolate as infectious bac clones .
moreover , induction of cytolytic disease by some of the bac - derived viruses demonstrates that the cloned viruses retain the biological characteristics of the parent virus .
interestingly , the study also showed that no viruses from any of the individual clones were able to induce the disease to the same levels as the wild - type virus .
similar observations have also been made with bac clones of oncogenic mdv strains such as rb-1b .
such differences may be due to the quasispecies nature [ 20 , 21 ] that could provide selective fitness advantages for more virulent strains in the wild - type virus .
alternatively , the cloning steps involved in the construction of the bac may selectively disadvantage the more virulent viruses in the pool .
our study shows that individual viral genomes , despite originating from a single population of parental virus , can differ in virulence in disease models .
in fact , the isolation of bac clones pc12/130 - 10 and pc12/130 - 15 that behave at either end of the disease spectrum , with respect to the induction of early cytolytic disease and mortality , provides a great opportunity to identify the molecular virulence determinants by direct sequence analysis as well as by the application of reverse genetics .
we report here the cloning of the full - length genome of a hypervirulent uk mdv strain c12/130 that induces acute cytolytic disease with brain lesions .
the ability of these infectious bac clones to reconstitute viruses that have very similar biological characteristics to the parent wild - type virus provides the opportunity to carry out investigations into the identification of molecular determinants associated with the distinct features of this hypervirulent strain to induce acute cytolytic disease .
we also show that different bac clones that represent individual genomes of viruses , despite originating from a single source , differed in virulence .
the construction of bac clones of these important viral pathogens that differ in virulence offers the opportunity to identify viral determinants associated with acute cytolytic disease and neuronal pathogenicity . | bacterial artificial chromosome ( bac ) vectors containing the full - length genomes of several herpesviruses have been used widely as tools to enable functional studies of viral genes .
marek 's disease viruses ( mdvs ) are highly oncogenic alphaherpesviruses that induce rapid - onset t - cell lymphomas in chickens .
oncogenic strains of mdv reconstituted from bac clones have been used to examine the role of viral genes in inducing tumours .
past studies have demonstrated continuous increase in virulence of mdv strains .
we have previously reported on the uk isolate c12/130 that showed increased virulence features including lymphoid organ atrophy and enhanced tropism for the central nervous system . here
we report the construction of the bac clones ( pc12/130 ) of this strain .
chickens were infected with viruses reconstituted from the pc12/130 clones along with the wild - type virus for the comparison of the pathogenic properties .
our studies show that bac - derived viruses induced disease similar to the wild - type virus , though there were differences in the levels of pathogenicity between individual viruses .
generation of bac clones that differ in the potential to induce cytolytic disease provide the opportunity to identify the molecular determinants of increased virulence by direct sequence analysis as well as by using reverse genetics approaches on the infectious bac clones . |
macular retinoschisis and serous macular detachment have been broadly described in the presence of congenital optic nerve abnormalities , mainly optic nerve pits and colobomas.1,2 recently , three papers have described a similar maculopathy in association with an acquired optic disc cup enlargement in glaucoma patients.35 the purpose of this paper is to present a case of maculopathy secondary to an enlarged optic disc cup , to show the usefulness of optic coherence tomography in the diagnosis of this entity , to discuss its pathogenesis and , finally , to propose a surgical approach .
a 64-year - old , nonhypertensive , emmetropic woman without any relevant past medical history presented at our emergency department due to a sudden loss of vision in her right eye .
this was her only useful eye , because she presented a long history of low vision of unknown origin in her left eye ( counting fingers at 20 cm ) , for which she had never requested medical attention .
right eye funduscopy showed a central retinal vein occlusion , and a cup / disc ratio of 0.7 ( figure 1a ) .
left eye funduscopy showed a cup / disc ratio of 0.8 without any other abnormality in the optic nerve head , and a serous macular detachment ( figure 1b ) .
retinal fluorescein angiography showed a choroidal silence and signs of stargardt disease in both eyes ( figure 1d and e ) .
optic coherence tomography showed a macular detachment in her left eye communicating with an enlarged optic disc cup , with no evidence of vitreomacular traction ( figure 1c ) .
she was diagnosed as having primary open - angle glaucoma in both eyes , for which she started treatment with latanoprost , and was also diagnosed with central retinal vein occlusion in her right eye .
surgery was recommended in order to resolve the serous macular detachment in her left eye .
the posterior hyaloid was found to be firmly attached to the temporal margin of the optic disc .
before the retina was reapplied , three rows of endolaser photocoagulation burns were applied to the temporal margin of the optic disc .
the aim of this technique is to treat the retinal pigment epithelium only , while avoiding damage to the neurosensory retina .
optic coherence tomography performed six months after surgery showed resolution of the macular retinoschisis , and persistence of the membrane over the optic disc cup ( figure 1f , h , and i ) . however , visual acuity decreased to hand motion in her left eye six months after surgery , and papillary atrophy developed in spite of good intraocular pressure control ( all measures inferior to 17 mmhg ) with latanoprost ( figure 1h )
. this may be due to the progression of her previous glaucomatous damage , a common course in advanced glaucoma patients even when their intraocular pressure is normalized ; to foveal atrophy because of the chronicity of the retinoschisis and macular detachment ; to high intraoperative intraocular pressure ; to endolaser photocoagulation burns ; or to intraocular pressure elevation due to endotamponade .
macular retinoschisis with or without macular neurosensory detachment has been described in congenital optic nerve abnormalities .
gass6 and other authors7 have suggested the fluid to be of cerebrospinal origin , which would gain access from the subarachnoid space and through the optic nerve defect to the subretinal space .
the more accepted hypothesis today is sugar s theory , ie , a liquefied vitreous passes through an optic nerve defect ( pit ) and dissects the retinal layers , after which it migrates into the subretinal space , causing a neurosensory retinal detachment.8 brown et al observed that more than three quarters of patients with macular detachment associated with optic nerve pits developed posterior vitreous detachment , while patients with optic nerve pits alone did not develop posterior vitreous detachment.9 hence , posterior vitreous traction may play a role in the pathogenesis of maculopathy . in our patient , there were no previous ophthalmic reports documenting the presence of a previous vitreous detachment .
recently , a similar maculopathy associated with an enlarged optic disc cup has been described.35 an increase in intraocular pressure2 or structural damage to the optic disc due to ganglion cell loss may facilitate the flow of liquefied vitreous through a small dehiscence in the inner part of an enlarged optic disc cup .
other causes of exudative macular detachment without angiographic leakage include hyperviscosity syndromes , like waldenstrm macroglobulinemia , multiple myeloma , endocarditis , leukemia , ischemic microvasculopathies like diabetes mellitus and hypertension , and even intracranial trauma ( eg , shaken baby syndrome).10 in contrast , macular detachment in exudative age - related macular degeneration , vogt koyanagi harada disease , central serous retinopathy , malignant hypertension , posterior scleritis , and sympathetic ophthalmia , among other conditions , will show one or more pinpoint leaks in the retinal pigment epithelium on fluorescein angiography.10 optic coherence tomography imaging has shown the presence of membranes spanning optic disc pits.11 similar membranes have been described in patients with large , acquired optic nerve cupping.4,5 it has been postulated that tiny holes in these membranes covering the optic nerve defect may allow the entry of fluid from the vitreous cavity , initially causing retinoschisis and later on a neurosensory macular detachment.5 in fact , pilon et al12 described a patient with a macular detachment associated with a fractured inner limiting membrane over a complete excavation of the optic disc cup . in the case presented here , the only optic nerve abnormality observed associated with the presence of retinoschisis was an enlarged optic disc cup confirmed by optic coherence tomography imaging and associated with a membrane covering the optic disc cup .
the patient did not have any other signs or symptoms of systemic disease that may have accounted for the exudative macular detachments .
additionally , in these conditions , macular detachments are usually bilateral and other signs are present on funduscopy , like roth spots or turbid subretinal fluid from hyperviscosity syndromes or leukemia.10 in our case , optic coherence tomography clearly showed a communication between the deep optic disc cup and the schisis .
the presence of a membrane over the optic disc cup shown in the optic coherence tomography of this eye is highly reminiscent of the membranes described over the optic nerve pits.11 in the series by doyle et al,11 the membrane was present in three of five eyes without maculopathy , and was absent in the three eyes with maculopathy .
however , in our case , the membrane can be seen in an eye with retinoschisis and macular detachment . even though there is no universally accepted treatment for optic disc pit maculopathy
intraocular gas tamponade followed by face - down positioning facilitates macular reattachment.13 several rows of laser photocoagulation burns between the retinal detachment and the optic nerve may close the communication and stop fluid flow .
we hypothesize that mechanical tractions exerted on the retina from membranes covering the optic disc cup may create small retinal dehiscences in acquired cupped optic discs , as described in congenital optic nerve abnormalities , which will enable the liquefied vitreous to enter the intraretinal or subretinal space .
spontaneous release of tractions may lead to the closure of these communications , as described after posterior vitreous detachment in macular detachment associated with optic nerve pits.9 structural damage to retinal layers producing intraretinal degeneration due to chronicity may perpetuate the intraretinal cyst .
we believe that cases of macular retinoschisis or detachments in glaucoma patients may go undetected or be misdiagnosed as cystoid macular edema or other retinal or choroidal diseases .
the common use of optic coherence tomography imaging has made possible the diagnosis of this syndrome . | we describe a case of maculopathy consisting of macular retinoschisis and serous macular detachment occurring in a patient with an acquired enlarged optic disc cup , similar to the maculopathy observed in congenital optic nerve abnormalities , mainly optic nerve pits and colobomas , without vitreomacular traction nor angiographic leak .
pars plana vitrectomy with argon laser endophotocoagulation and gas tamponade was found to be useful .
traction from membranes covering deep optic disc cups may create small retinal dehiscences , as described in congenital optic nerve abnormalities , which will enable the liquefied vitreous to pass , leading to retinoschisis with or without associated neurosensory detachment .
vitrectomy , photocoagulation , and gas tamponade may be a useful therapy for this entity . |
traumatic injury is the leading cause of morbidity and mortality , which affects many parts of the body , including the brain , extremities , and internal organs .
the incidence of life - threatening complications , such as systemic inflammatory response syndrome ( sirs ) and acute lung injury ( ali ) , in severely injured trauma patients remains between 30% and 50% [ 1 , 2 ] .
sirs induced by severe trauma or other injuries is a clinical syndrome initiated by dysregulation of inflammation , which could lead to various tissue injuries culminating in multiple organ dysfunction / failure syndrome ( mods / mof ) .
bone marrow - derived mesenchymal stem cells ( bmscs ) , also referred to as marrow stromal cells , are a multipotential lineage characterized by the capacity for extracorporeal expansion and the ability to differentiate into bone , cartilage , and adipose tissues .
numerous studies indicated that bmscs can be an effective modality for cell - based immunomodulatory therapies in various diseases , such as sepsis , endotoxemia , diabetes , and lung injury [ 39 ] , especially for reducing of inflammation [ 4 , 5 , 10 ] .
several clinical trials assessing the efficacy of bmscs in immune - mediated diseases are currently underway .
quick and efficient response to microbial infections is driven by recognition of molecules broadly shared by a variety of pathogens , which are distinguishable from host molecules named pathogen associated molecular patterns ( pamps ) .
pattern - recognition receptors ( prrs ) that contain membrane - bound prrs , including toll - like receptors ( tlrs ) and other cytoplasmic proteins , recognize the pamps . upon binding with the pamps , tlr2 and tlr4
then activate nf-b and subsequently promote cytokine synthesis , which include il-1 , il-6 , and tnf- [ 11 , 12 ] .
the network of tlrs and prrs mediates the response of bmscs to inflammatory stimuli , such as lps [ 13 , 14 ] .
however , how tlrs modulate the bmsc activity is not clearly elucidated . since tlr2 and tlr4 response to acute otitis through activation of nf-b , we hypothesized that bmscs ameliorate the inflammation damage of alveolar macrophages and huvecs through the inhibition of tlr2 and tlr4 mediated nf-b pathways .
louis , mo ) supplemented with 10% fetal bovine serum ( fbs ) ( gibco , carlsbad , ca , usa ) and 1% penicillin / streptomycin ( solarbio , beijing , china ) at 37c in a humidified atmosphere of 5% co2 .
( suzhou , china ) were cultured in 10% fbs - dmem - lg ( gibco , carlsbad , ca , usa ) .
the surface markers for bmscs differentiation of adipocytic , osteogenic , and chondrogenic lineages were characterized as previously reported .
monolayer permeability was quantitated by spectrophotometric measurement of the flux of evans blue - albumin across huvecs as described previously .
huvecs ( 1 10 ) were seeded in 24-well transwell inserts ( 5 m pore size , corning incorporated , ny , usa ) and cultured with 10% fbs dmem overnight and then changed with serum - free medium for another 24 hours .
the various numbers of bmscs were seeded at the bottom of the same 24-well plate with serum - free media .
lps was added to the transwell inserts at a final concentration of 100 ng / ml for different time points ( 1 , 3 , 6 , 12 , and 24 h ) .
after that , the bmscs were digested by trypsin - edta solution to terminate the effects of bmscs and 100 l hank 's solution containing evans blue- ( eb- ) conjugated bovine serum albumin ( final concentration 0.67 mg / ml ) was added to the transwell inserts , while 600 l 4% bsa was added to the lower plate chamber .
after incubation at 37c for 1 hour , 100 l bsa solution from the lower chamber was harvested and measured for the absorbance at 620 nm .
the huvecs permeability capacity was calculated as follows : evans blue dye - labeled albumin ( eb - albumin ) leak rate = od620leaked eb - albumin / od620total eb - albumin 100% .
alveolar macrophages or huvecs ( 1 10/well ) were seeded in a 6-well plate , after 24-hour incubation , bmscs ( 2 10/well ) were seeded in the 6-well transwell inserts ( 5 m pore , corning incorporated , ny , usa ) at the indicated time points ( 1 , 3 , 6 , 12 , and 24 h ) .
lps ( 100 ng / ml ) was then added to the lower chamber for 1 h. alveolar macrophages or huvecs lysate was collected for rna and protein analyses , and the cell - free supernatants were collected for elisa detection .
/ huvecs were lysed in the ripa buffer ( thermo scientific , rockford , usa ) supplemented with 1% pmsf and 1% protein phosphatase inhibitor mixture ( p1260 , applygen , beijing , china ) .
the concentration of the proteins was measured with the bicinchoninic acid kit ( thermo scientific , rockford , usa ) .
rabbit anti - tlr2 , tlr4 , and phosphorylated p65 unit of nf-b antibodies were obtained from cell signaling technology .
horseradish peroxidase- ( hrp- ) conjugated goat anti - rabbit antibodies were purchased from bio - rad .
ecl - plus chemiluminescent reagent ( thermo scientific , rockford , usa ) was used to visualize the specific proteins .
relative concentration of proteins was quantitated using the image j software ( national institutes of health , bethesda , usa ) .
total rna was isolated from cells using the trizol rna isolation reagents ( life technologies ) .
the first - strand cdnas were converted using the superscript iii reverse transcriptase ( invitrogen , carlsbad , ca ) according to the manufacturer 's protocols .
real - time rt - pcr analysis was performed on abi 7500 sequence detection system using the ultrasybr mixture ( cw bio co. ltd , beijing , china ) .
the pcr primer sequences are gapdh forward 5-tggagtctactggcgtctt-3 , reverse 5-tgtcatatttctcgtg gttca-3 ; tlr4 forward 5-ctgcatagaggtagttcct-3 , reverse 5-tccagcc actgaagttctga-3 ; tlr2 forward 5-ggagactctggaagc atg-3 , reverse 5-gcatcct gaagcctgtg-3. the supernatants collected from coculture system were centrifuged for 10 minutes at 1000 g ( 4c ) to remove cell debris .
the levels of tnf- and il10 were measured using commercially available enzyme - linked immunosorbent assay ( elisa ) kits ( bd biosciences , san diego , ca , usa ) according to the instructions provided by the manufacturer .
spss 17.0 software was used to perform the statistical analysis and values are presented as the means standard deviations ( sd ) ; all experiments were repeated at least three times .
the one - way anova was used to determine the significance of differences between various groups .
to assess how bmscs affected huvecs permeability induced by lps , huvecs with or without coculture with bmscs were stimulated by lps for the indicated times . without coculture with bmscs ,
the eb - albumin leaking rate ranged from 5.35% ( at 1 h ) to 7.72% ( at 24 h ) in the lps group ( figure 1 ) . compared with the lps group ,
the eb - albumin leaking rates in the bmsc coculture group were reduced in a bmsc cell number- and time - dependent manner .
the eb - albumin leaking rate in the 1 10/ml bmscs group was decreased 3 hours after coculture .
the effects were less significant in the group with 1 10/ml bmscs and more significant in the group with 1 10/ml bmscs ( figure 1 ) . to determine whether lps stimulated expression of tlr2 , tlr4 , and p65 in macrophages and huvecs was affected by bmscs , alveolar macrophages and huvecs cells were cocultured with bmscs for the indicated time followed by lps treatment .
western blot ( figure 2 ) and real - time rt - pcr analyses ( figure 3 ) showed that lps administration increased expression of tlr2 , tlr4 , and p65 within 1 hour after the treatment .
however , the activity of lps was attenuated by coculture with bmscs in both alveolar macrophages and huvecs ( figures 2 and 3 ) . to determine whether bmscs regulated the release of tnf- and il10 from alveolar macrophages and huvecs in response to lps stimulation , the conditioned medium was collected from the coculture system and the concentrations of il10 and tnf-
it was clear that concentration of tnf- in the medium was increased after lps stimulation within 1 hour and the effects lasted for 24 hours .
in contrast , il10 was reduced by lps stimulation , while coculture with bmscs increased medium il10 production .
the results indicate that bmscs suppress lps - induced inflammation by decreasing tnf- and increasing il10 releases ( figure 4 ) .
bmscs treatments have been shown to reduce inflammatory response in human and animal models in response to injury .
the results also showed that bmscs restricted the inflammatory responses of huvecs and alveolar macrophage stimulated by lps and therefore protected huvecs from damage induced by the endotoxin .
the data indicate that attenuating lps - induced tnf- pathway activation in huvecs and macrophage by bmscs contributes to the protection of huvecs from endotoxin - induced damage by bmscs .
our data demonstrated that lps increased the permeability of huvecs monolayers in a time - dependent manner . although the extent of the activity was lower than that after coculture for a longer time , the protection effects were detectable within one hour .
since bmscs and huvecs were cultured separating by the transwell membrane , the effects of bmscs must be mediated by soluble factors released from bmscs .
however , we did not rule out the possibility that bmscs sequestrated lps and therefore protected the endothelial cells .
although lps still induced huvecs damage in the coculture , the eb - albumin leaks were reduced compared with the group without coculture with bmscs .
we observed that the protective effect of bmscs on huvec was cell number - dependent .
it appeared that the bmscs released sufficient protective molecules to protect endothelial cells within one hour . therefore , immediately administration of bmscs to sirs patients shall have beneficial effects .
furthermore , the results were in line with previous reports that lps leads to persistent damage of huvecs [ 18 , 19 ] . however , it was different from the report that the damage of huvec by lps is not time - dependent .
we cultured the cells for 24 hours to reach the confluence , followed by serum starvation for 24 hours and lps treatment .
this method is different from the published one where the cells were cultured for 4 days prior to the experiments .
it is well documented that cells use tlr2 and tlr4 to recognize pamps expressed by bacteria .
activation of tlr2 and tlr4 leads to activation of mapk and nf-b pathways and production of inflammatory cytokines , including il-1 , il-6 , and tnf- [ 2022 ] . in this study
, we showed that lps promoted expression of tlr2 and tlr4 in alveolar macrophages and huvecs .
however , how expression of tlr2 expression was increased by lps is unknown and deserves future investigations . tnf- and
furthermore , the lps effects were diminished when the huvecs and macrophages were cultured with bmscs .
tnf- is a potent inflammatory factor and il10 is a key anti - inflammatory cytokine .
downregulation of tnf- and upregulation of il10 in huvecs and macrophage indicate that the inflammatory reactions were suppressed .
the results suggest that bmscs have the ability to alleviate pathogen - induced inflammation damage in huvecs and macrophages . in conclusion
, the results showed that bmscs attenuated the activity of lps on the inflammatory reaction of huvecs and alveolar macrophages through inhibiting upregulation of tlr2 , tlr4 , and p65 expression , as well as downregulating tnf- release and upregulating il10 release . | background .
systemic inflammatory response syndrome ( sirs ) accompanied by trauma can lead to multiple organ dysfunction syndrome ( mods ) and even death .
early inhibition of the inflammation is necessary for damage control .
bone marrow mesenchymal stem cells ( bmscs ) , as a novel therapy modality , have been shown to reduce inflammatory responses in human and animal models .
methods . in this study , we used western blot , quantitative pcr , and enzyme - linked immunosorbent assay ( elisa ) to assess the activity of bmscs to suppress the inflammation induced by lipopolysaccharide ( lps ) in human umbilical cord endothelial cells ( huvecs ) and alveolar macrophages . results .
our results demonstrated that lps caused an inflammatory response in alveolar macrophages and huvecs , increased permeability of huvec , upregulated expression of toll - like receptor ( tlr ) 2 , tlr4 , phosphorylated p65 , downregulated release of il10 , and promoted release of tnf- in both cells .
coculture with bmscs attenuated all of these activities induced by lps in the two tested cell types . conclusions . together
, our results demonstrate that bmscs dosage dependently attenuates the inflammation damage of alveolar macrophages and huvecs induced by lps . |
ectopic liver tissue is a rare entity that involves the presence of hepatic tissue in a number of sites outside of the native liver such as the gallbladder , hepatic ligaments , omentum , retroperitoneum , and thorax [ 15 ] . in most situations ,
rarely , they may present with symptoms of abdominal pain secondary to torsion , compression , or obstruction of adjacent organs , and rupture secondary to malignant transformation [ 1 , 6 , 7 ] .
herein , we report a case of ectopic liver tissue complicated by acute hemorrhage without any evidence of underlying malignancy .
an otherwise healthy 25-year - old female presented to our emergency department with complaints of acute onset of epigastric pain and nausea with bilious emesis .
workup in the way of liver function tests and abdominal ultrasound did not demonstrate evidence suggesting biliary or gallbladder pathology , and as such she was discharged home .
she therefore underwent evaluation with a computed tomography that demonstrated a soft tissue mass located posterior to the gallbladder ( figure 1 ) .
again , a complex cystic structure of indeterminate etiology was observed at the porta hepatis without evidence of communication with either the biliary or vascular structures . at the time , the differential diagnosis included a ruptured hepatic adenoma , biliary cystic lesion , or enteric cyst .
secondary to these findings and her persistent symptoms the patient was taken to the operating room . at the time of laparoscopy a hemorrhagic pedunculated mass
was identified attached to the infundibulum of the gallbladder once the fundus was retracted in a cephalad direction ( figure 2 ) .
it was easily dissected off the hilar structures by blunt dissection and then resected by ligating a small pedicle of tissue connecting this mass to the gallbladder infundibulum near the cystic duct by using a harmonic scalpel .
there was also a considerable amount of inflammation to the infundibulum of the gallbladder in proximity to this hemorrhagic mass with the remainder appearing normal .
we believe the cholecystitis was secondary to inflammation from the hemorrhagic mass . as mentioned previously , her initial ultrasound did not show any evidence of cholecystitis . even though one could expect this inflammation to resolve once the hemorrhagic mass was removed
, we decided to perform a cholecystectomy because there was considerable dissection within the region of the cystic duct and the concern of potential ischemia and stricture did exist .
she was discharged home on the first postoperative day and was asymptomatic when seen in follow - up .
gross pathology of the hilar mass revealed a 1.2 2.8 4.5 cm firm purple ovoid structure .
the presence of hepatic lobules with central veins and organized portal structures ruled out adenoma and focal nodular hyperplasia ( figure 3 ) .
histologic evaluation of the gallbladder demonstrated localized cholecystitis in the area adjacent to the mass .
anomalous liver anatomy is classified as either accessory liver lobes where additional hepatic parenchyma is present outside of the native liver but is still connected to it or ectopic liver tissue where normal hepatic parenchyma is found outside of the liver with no hepatic connection .
the incidence of ectopic liver tissue has been reported to be anywhere from 0.24%0.47% as diagnosed at the time of laparotomy or laparoscopy [ 1 , 8 ] . in most situations ,
ectopic liver tissue is found on or near the gallbladder [ 2 , 6 ] . a summary the cases presented in the literature including patient demographics , clinical presentation , location of ectopic liver tissue , and outcomes
is presented in table 1 . though there have been reports of ruptured ectopic liver tissue in the setting of malignant degeneration into hepatocellular carcinoma ( hcc ) ,
this is the first case to our knowledge where benign hepatic tissue presented with symptomatic spontaneous hemorrhage .
there has been evidence to suggest that ectopic liver has a propensity to develop into malignancy .
theoretically , they may be susceptible to transformation to hcc secondary to their incomplete vascular and ductal systems that are incapable of acting in a metabolically appropriate manner .
this theory may be further supported by the fact that the majority of cases where hcc is reported within ectopic liver tissue occur when there is no evidence of underlying cirrhosis or chronic inflammation of the native liver [ 2 , 4 , 9 ] . in summary ,
ectopic liver tissue can become symptomatic secondary to mass effect , spontaneous rupture , or malignant degeneration . given these findings ,
unfortunately , the literature on this subject is limited and therefore it is difficult to draw any conclusions as to risk factors for development of complications such as location of tissue , use of oral contraceptives , and size of the lesion . with increased awareness of this topic and better imaging techniques , additional information may allow for recognition of risk factors and recommendations for surgical intervention . | ectopic liver tissue is a rare clinical entity that is mostly asymptomatic and found incidentally . in certain situations , however , patients may present with symptoms of abdominal pain secondary to torsion , compression , obstruction of adjacent organs , or rupture secondary to malignant transformation .
herein , we report a case of a 25-year - old female that presented with acute onset of epigastric pain found to have ectopic liver tissue near the gallbladder complicated by acute hemorrhage necessitating operative intervention in the way of laparoscopic excision and cholecystectomy . the patient 's postoperative course was uneventful .
gross pathology demonstrated a 1.2 2.8 4.5 cm firm purple ovoid structure that histologically revealed extensive hemorrhagic necrosis of benign ectopic liver tissue . |
current use of laparoscopy in the evaluation and management of trauma patients has been a natural extension of this trend .
although utilized for both blunt and penetrating injuries , laparoscopy has gained the most widespread acceptance as a useful tool in the management of patients with penetrating abdominal injuries . its ability to accurately determine anterior peritoneal penetration from stab and
others have expanded its role beyond simply a screening tool for injury , to its current use in some centers as a diagnostic and therapeutic modality .
the purpose of this study was to evaluate the role of laparoscopy in the trauma setting at our urban level ii trauma center .
more specifically , we examined its use in the management of hemodynamically stable trauma patients with penetrating anterior abdominal injuries .
we also sought to determine how our results compared with those of other centers regarding the widely accepted laparoscopic advantages of reduced morbidity , decreased rates of negative laparotomy , and shortened length of hospital stay ( los ) .
we conducted a retrospective chart review of 4541 trauma patients who were admitted to our level ii trauma center between july 1 , 1999 and july 31 , 2002 . penetrating injuries accounted for 817 ( 18% ) of these trauma admissions .
there were 209 penetrating injuries isolated to the abdomen , of which 116 were gunshot wounds ( gsw ) and 93 were stab wounds ( sw ) .
the first group consisted of hemodynamically stable patients without evidence of abdominal peritoneal penetration based on physical examination , local wound exploration , or further confirmatory studies , including focused abdominal sonography for trauma ( fast ) , computed axial tomography ( ct ) , or diagnostic peritoneal lavage ( dpl ) , or all of these .
the additional confirmatory studies were not applied in a standard fashion to all patients , but rather selected based on clinical indication and attending physician preference .
in addition , stab wounds with peritoneal penetration , but no peritoneal signs , also underwent a course of observation .
the second group of patients was those with peritoneal signs or confirmed evidence of abdominal peritoneal penetration based on physical examination , local wound exploration , or further confirmatory studies .
the third group of patients was taken to the operating room for laparoscopic evaluation due to questionable peritoneal penetration .
criteria for laparoscopy was a hemodynamically stable patient with an injury trajectory suggestive of peritoneal penetration that could not reliably be ruled out based on physical examination or further confirmatory studies .
no attempt was made to laparoscopically assess the extent of the intraabdominal injuries or make therapeutic interventions .
laparotomy was negative if it was discovered after the abdomen was opened that no peritoneal penetration had occurred .
a nontherapeutic laparotomy was one that confirmed peritoneal penetration with either no intraabdominal injuries or injuries so minor that they did not require surgical repair .
the patients in these 2 groups were closed without therapeutic intervention and admitted to the floor for postoperative recovery .
the laparoscopic findings were described as either positive or negative based on evidence of peritoneal penetration .
figure 1 details the algorithm used for management of our patients with penetrating abdominal wounds .
injury severity score ( iss ) and length of hospital stay ( los ) were calculated for each patient in the study .
morbidity and mortality figures were also generated for each patient from our computer database by using standard methodology to define associated complications .
penetrating abdominal injuries accounted for 209 of our trauma admissions , of which 116 were gsw and 93 were sw .
gender breakdown of these patients was male , 171 ( 82% ) and female , 38 ( 18% ) .
thirty - three patients ( gsw=9 , sw=24 ) were observed in the emergency department based on their initial physical examination , radiologic studies , or additional confirmatory studies , or all of these .
the majority of the gsw patients received immediate laparotomies due to the higher ballistic forces associated with these injuries . in general , gsw to the anterior abdomen required laparotomy unless the wound was tangential .
table 1 provides the negative , nontherapeutic , and therapeutic outcomes in the formal laparotomy group with regards to the number and percentage of procedures and los for patients with gsw and sw .
a review of the negative laparotomies revealed that possibly 8 of 10 gsw and all 14 stab wounds could have been done laparoscopically , based on the location of the entrance wound in the anterior abdominal wall . however , 2 of the negative gsw laparotomies assessed tangential wounds that would not have been well visualized by laparoscopy alone .
all of these patients had anterior abdominal wounds , and 2 patients had flank wounds in addition to the anterior wounds .
of these 22 patients , 7 had an additional confirmatory test prior to going to the operating room ( table 2 ) .
eight sw were converted to an open procedure , and 7 had laparoscopy only ( table 3 ) .
additional confirmatory test in patients managed with laparoscopy * gsw = gunshot wound ; ct = computed tomography ; fast = focused abdominal sonography for trauma ; sw = stab wounds ; los = length of hospital stay .
results of laparoscopy group results of laparotomies after conversion table 5 lists the number and percentage of gsw and sw patients who underwent laparotomy , laparoscopy , or were observed .
mortality was 13% ( gsw=20 , sw=0 ) for the laparotomy group , and 0% ( gsw=0 , sw=0 ) for the laparoscopy group .
morbidity was 27% ( gsw=42 , sw=7 ) in the laparotomy group and 14% ( gsw=1 , sw=2 ) in the laparoscopy group .
these numbers reflect the increased severity of injury with the laparotomy group . however , we found no difference in morbidity or mortality when we compared data for the negative laparotomy group and the negative laparoscopy group .
management of gunshot wounds versus stab wounds mean los was 7.9 days for the laparotomy patients and 3.0 days for the laparoscopy patients .
this difference can be attributed to the higher severity of injury associated with the laparotomy group . however
, a more useful comparison of los is that between the negative laparotomy group and the negative laparoscopy group , which revealed an los of 4.1 and 1.9 , respectively .
laparoscopic evaluation of the peritoneal cavity is not a new concept , having first been described by kelling over a century ago .
the first reports demonstrating the utility of laparoscopic surgery in the evaluation of trauma patients were published soon thereafter in the 1920s .
these early trauma studies investigated laparoscopy as a method to diagnose internal bleeding in patients with traumatic abdominal injuries . reports describing similar experiments were published sporadically throughout most of the last century .
however , mainly due to technological limitations , it would be many years before laparoscopic surgical techniques would prove their practical utility and gain widespread acceptance .
it is now evident that despite the lack of early enthusiasm in the surgical community for these new techniques , the laparoscopic pioneers correctly recognized the potential benefits of minimally invasive surgery in the trauma patient .
recent technologic advances in optics and laparoscopic instrumentation have greatly broadened the applications for minimally invasive surgery .
we now have a better understanding of the physiologic changes and complications associated with these procedures .
increased training and utilization of minimally invasive procedures in all areas of surgery has come an increase in expertise among trauma surgeons .
these techniques have evolved from what was once a novelty into an important part of every surgeon 's practice . for trauma patients
, laparoscopy provides clear visualization of the peritoneal space and anterior abdominal wall , and unlike other diagnostic modalities , has the additional benefit of potential for therapeutic intervention .
however , despite its increased use in trauma , the optimum role of laparoscopy in this setting has not yet been clearly defined .
there continues to be variation among trauma centers on how best to optimize its application , taking full advantage of its benefits while overcoming its limitations .
laparoscopy has been used as a screening , diagnostic , and therapeutic tool to evaluate both blunt and penetrating trauma at various centers .
villavicencio and aucar authored an extensive review in 1997 in which they compared outcomes collected from 37 separate studies , involving over 1900 patients .
a review of the data showed that it was most useful as a screening tool , missing only 1% of injuries and preventing 63% of patients from unnecessary laparotomies .
the data were less encouraging when laparoscopy was used as a diagnostic tool , with missed injury rates reported between 41% and 77% .
these numbers reflect a diagnostic accuracy that is unacceptable to most surgeons who have used the laparoscope less frequently in this manner .
laparoscopy is infrequently used as a therapeutic tool ; however , several reports have demonstrated favorable results with laparoscopic repair of a variety of intraabdominal injuries , including the dia - phragm , liver , gallbladder , spleen and bowel .
emergency department evaluation of the injured patient has evolved greatly over the years , based mainly on the technology of the time .
trauma surgeons have had available a variety of diagnostics tools to assist with the management of their patients , including dpl , fast , and ct .
the increased availability of laparoscopy now offers them even more flexibility during the workup of injured patients .
certainly the evaluation of every trauma patient starts with the advanced trauma life support ( atls ) primary survey followed by a thorough physical examination .
it is important to carefully inspect the patient 's wounds , because findings on the initial physical assessment usually determine the decision - making algorithm .
local wound exploration is limited in its ability to determine specific intraabdominal injuries , but it can often determine peritoneal penetration and thereby avoid the need for further studies . in patients who are obtunded due to central nervous system dysfunction or intoxication as well as in those with distracting injuries to multiple body systems , the physical examination may be less reliable .
wounds with tangential trajectories can also be difficult to accurately assess , necessitating additional diagnostic studies .
diagnostic peritoneal lavage is simple , inexpensive , and can be quickly performed in the emergency department .
however , dpl is limited by poor specificity , inability to accurately assess the retroperitoneum , and potential for missed hollow viscus or diaphragmatic injuries .
it is also an invasive test that has some risk , albeit low , for procedural complications .
although dpl has been considered the standard modality to assess traumatic intraabdominal injury for many years , its use is now declining in favor of more accurate , less invasive modalities , such as ultrasound ( fast ) and ct .
we have significantly decreased the number of dpls performed at our institution in recent years as well , relegating its use to screening for late presenting potential hollow viscus injuries or rapid evaluation of blunt injuries if fast is unequivocal or unavailable .
technological improvements have greatly enhanced the capabilities of ct and ultrasound , both of which now have an important role in trauma management .
fast is now widely used in most trauma centers ; however , its major role is in blunt trauma .
it has a low specificity for organ injury , but can effectively determine the presence of free fluid in the gravity dependent spaces of the peritoneal cavity .
some centers have used positive fast examination findings as an indicator for laparotomy in penetrating trauma .
improvements in ct speed and resolution have allowed for reliable evaluation of both the peritoneum and retroperitoneum .
ct findings can often confirm or rule out peritoneal penetration based on a more clearly delineated wound trajectory or evidence of intraabdominal injury .
unlike blunt injuries that can often be managed by observation and monitoring , ct confirmation of penetrating intraabdominal injury warrants laparotomy at our institution .
the results of our study were consistent with those of other centers regarding the generally accepted laparoscopic advantages of decreased rates of negative laparotomy , shortened length of hospital stay , and quicker return to normal activity .
the laparotomy patients had many more pulmonary complications including atelectasis , pneumonia , and respiratory failure .
they also were found to have more wound complications including dehiscence , infection , and abscess formation .
the decreased mobility of the laparotomy patients led to one deep vein thrombosis in this group .
the results of our study did not show any difference in morbidity or mortality between the negative laparoscopy and the negative laparotomy groups .
we found that a decrease occurred in los from 4.1 days in the negative laparotomy group to 1.9 days in the negative laparoscopy group .
brandt et al looked at 21 trauma patients who underwent laparoscopic evaluation of both penetrating and blunt injuries , and found that emergency laparoscopy was 100 percent accurate in determining the need for laparotomy .
a more recent retrospective review demonstrated a direct correlation between increased use of laparoscopy and decreased rates of negative laparotomy .
our study revealed that laparoscopic evaluation spared many patients unnecessary laparotomies . after reviewing the operative reports of patients with negative laparotomies
, it was determined that possibly 8 of 10 gsw and all 14 stab wounds could have been done laparoscopically .
two of the 10 gsw patients had lateral or posterior injuries that required a more detailed evaluation of the retroperitoneum than would have been possible by laparoscopy alone .
although we currently use the laparoscope solely as a screening tool for peritoneal penetration , the next logical progression for us is to conduct a more effective laparoscopic evaluation of specific organ structures in the trauma setting . this could potentially decrease or eliminate the conversions from laparoscopy to laparotomy that were nontherapeutic .
this would entail a systematic laparoscopic evaluation of the entire peritoneal cavity , including running the small bowel , visualizing the diaphragm and solid organs , and accurately assessing for evidence of pelvic or retroperitoneal injury .
the threshold for conversion would vary among surgeons based on laparoscopic expertise and confidence in the laparoscopic examination .
data show that laparoscopy is a useful modality for evaluating and managing trauma patients with penetrating injuries .
we have found that it is particularly helpful as a screening tool for anterior abdominal wall wounds and lower chest injuries to rule out peritoneal penetration .
increased use of laparoscopy in select patients with penetrating abdominal trauma will decrease the rate of negative and nontherapeutic laparotomies , thus lowering morbidity , decreasing length of hospitalization , and provide for more efficient utilization of available resources . as technology and expertise among surgeons continues to improve , | background : minimally invasive surgery has become increasingly utilized in the trauma setting .
when properly applied , it offers several advantages , including reduced morbidity , lower rates of negative laparotomy , and shortened length of hospital stay .
the purpose of this study was to evaluate the role of laparoscopy in the management of trauma patients with penetrating abdominal injuries.methods:we conducted a 3-year retrospective chart review of 4541 trauma patients admitted to our urban level ii trauma center . penetrating abdominal injuries accounted for 209 of these admissions .
patients were divided into 3 treatment groups based on the characteristics of their abdominal injuries .
management was either observation , immediate laparotomy , or screening laparoscopy.results:thirty-three patients were observed in the emergency department based on their initial physical examination and radiologic studies .
after emergency department evaluation , 154 patients underwent immediate laparotomy . in this group , 119 therapeutic laparotomies , 11 nontherapeutic laparotomies , and 24 negative laparotomies were performed .
a review of the negative laparotomies revealed that possibly 8 of 10 gun shot wounds and all 14 stab wounds could have been done laparoscopically .
twenty - two patients underwent laparoscopic evaluation , 9 of which were converted to open procedures.conclusion:minimally invasive surgical techniques are particularly helpful as a screening tool for anterior abdominal wall wounds and lower chest injuries to rule out peritoneal penetration .
increased use of laparoscopy in select patients with penetrating abdominal trauma will decrease the rate of negative and nontherapeutic laparotomies , thus lowering morbidity and decreasing length of hospitalization . as technology and expertise among surgeons continues to improve , more therapeutic intervention may be done laparoscopically in the future . |
the renewable production
of co via the 2e/2h reduction of co2 is an energy conversion half
reaction of prime importance for the sustainable production of carbon - based
fuels .
reaction of co with water via the water gas shift ( wgs )
reaction produces h2 , and this co / h2 mixture
( syngas ) can be used to generate synthetic petroleum and other liquid
fuels using conventional fischer
, the use of renewable sources of electricity to drive
the electrolytic generation of co at ambient temperatures and pressures
provides an attractive route to the renewable production of liquid
fuels . over the past several decades
,
fervent effort has been aimed at
the study of molecular electrocatalysts for reduction of co2 to co. in recent years , extensive work has shown that properly
designed fac - tricarbonyl complexes of rhenium and manganese can catalyze this electrochemical reaction with good
selectivity and reasonable kinetics .
additionally , costentin and savant
have shown that iron porphyrins containing pendent proton donors can
promote conversion of co2 to co with remarkably high selectivity
and excellent current densities at low overpotentials .
although these molecular systems can be proficient co evolution
electrocatalysts , in order to incorporate such species into electrolytic
devices , it is necessary to tether these systems to conducting solid
supports , which is a nontrivial undertaking .
although recent
work has shown that immobilization of a cobalt porphyrin onto conducting
diamond or nickel cyclam onto a conducting
poly(allylamine ) support can promote
the electrocatalytic production of co , these heterogeneous architectures
do not currently display technologically relevant current densities
( fast kinetics ) for co2 conversion applications .
several heterogeneous cathode materials have been shown to promote
the rapid conversion of co2 to co ; however , only precious metals such as ag and au can catalyze this reaction with faradaic efficiencies ( fes ) that
are in excess of 80% while operating with appreciable current density
( competent rate ) at modest overpotentials ( reasonable cathodic half
reaction energy efficiency ) .
although
less expensive materials such as those based on cu and sn that are more economically suited
for renewable fuel synthesis show promise for reduction of co2 to formic acid , these systems generally do not show high
activities ( i.e. , appreciable current density / fast kinetics ) or selectivities
for co production .
moreover , inexpensive metallic cathodes typically
only activate co2 upon application of very large overpotentials , which has been a significant barrier to implementation
of such systems for the production of renewable liquid fuels . given the above considerations , the development of a robust and
inexpensive material that can promote the rapid and selective reduction
of co2 to co under ambient conditions is a key milestone
to the economically viable production of carbon - based fuels from renewables .
bismuth is an attractive material for heterogeneous catalyst development ,
as this metal has a negligible environmental impact and few significant
commercial applications , which sustains low and stable pricing for
this element . against this backdrop ,
our group recently developed the first bismuth - based catalyst for
the electrochemical conversion of co2 to co. this inexpensive
and easily prepared material was studied in mecn containing 0.1 m
tbapf6 as a supporting electrolyte , since this solvent / electrolyte
combination supports a large electrochemical window and is commonly
employed for co2 electrocatalysis .
efficient co production was realized with this system upon addition
of a 1,3-dialkyl substituted imidazolium based ionic liquid ( il ) promoter
such as 1-ethyl-3-methylimidazolium hexafluorophosphate ( [ emim]pf6 ) or 1-butyl-3-methylimidazolium hexafluorophosphate ( [ bmim]pf6 ) to the catholyte solution . since
this bismuth carbon monoxide evolving catalyst ( bi - cmec ) operates
in a catholyte solution of low proton availability ( the pka of the il promoter is 32 ) and the position of eco2/co is dependent on the proton donating ability of the
electrolyte , the equilibrium potential
for the 2e/2h conversion of co2 to co under these conditions is eco2/co = 1.78 v versus sce .
previous work showed that this system is highly active ,
as bi - cmec promotes co production with exceptional cathodic half reaction
energy efficiency ( co 85% ) and a fe over 90% at an applied overpotential of less than
= 200 mv . although the
efficiency of bi - cmec rivals the best noble - metal
cathodes described to date , our initial studies of this system relied
on electrodeposition of this bi material from concentrated aqueous
acid . since such solutions are incompatible
with co2 electrocatalysis , it was necessary to form bi - cmec
ex situ prior to studying the catalyst s co2 reduction
activity in mecn .
accordingly , we rationalized that it would be highly
beneficial to develop a method to electrodeposit bi - cmec directly
from the organic catholyte employed for co2 reduction experiments .
prior to pursuing the in situ formation of bi - cmec , however , we first
sought to optimize the activity of this electrocatalyst by varying
the composition of the catholyte solution and determining the extent
to which the catholyte anion impacted co2 activation .
we
also wondered whether the expensive and frequently used supporting
tetraalkylammonium electrolyte ( tbapf6 ) could be eliminated
from the catholyte solution while maintaining efficient co2 catalysis with the bi - cmec system .
since imidazolium based ils can interact with co2 and
have found application for gas separation / carbon sequestration and can serve as robust electrolytes for a variety of electrochemical and energy conversion applications , we hypothesized that
imidazolium salts such as [ bmim]pf6 could serve as both
a promoter for co2 activation at bi - cmec and the supporting
electrolyte in the catholyte solution . linear sweep voltammograms
( lsvs ) recorded in co2 saturated mecn using a glassy carbon
electrode ( gce ) onto which a film of bi - cmec had first been electrodeposited
( figure 1 ) showed that the addition of small
aliquots of [ bmim]pf6 results in polarization curves that
are nearly identical to those recorded in the presence of tbapf6 . this current response can not simply be attributed to reduction
of [ bmim ] at the electrode surface , as analogous cyclic
voltammograms recorded under an atmosphere of n2 did not
show a reduction wave at potentials less negative than 2.1
v versus sce ( all potentials in this manuscript
are reported with
respect to this reference ) . moreover , cv experiments conducted using
the gce substrate for 300 mm solutions of [ bmim]pf6 in
mecn under n2 show that the imidazolium is only reduced
at potentials more negative than 2.2 v versus sce ( figure s1 in supporting information ) . when taken
together , these voltammetry experiments suggest that the cathodic
feature observed in figure 1 corresponds directly
to the il promoted reduction of co2 by the bi - cmec covered
electrode . ( a )
lsv traces recorded for a gce covered by bi - cmec in co2 saturated mecn containing varying amounts of [ bmim]pf6 .
( b ) partial current density profiles for co production ( jco ) by bi - cmec and gce at 2.0 v in mecn
in the presence of various imidazolium based ils . upon establishing
that bi - cmec could promote reduction of
co2 to co in the presence of [ bmim]pf6 without
supporting
electrolyte , we sought to identify if other [ bmim ] salts
displayed comparable activities .
in particular , we were curious to
see if [ bmim ] salts comprising anions less expensive than
pf6 could be tolerated during electrocatalysis .
moreover , given that anions such as bf4 and pf6 can slowly hydrolyze , we were eager to identify if more robust [ bmim ] salts would also be good promoters of co2 reduction
by bi - cmec .
as such , [ bmim ] salts of bf4 , cl , br , and
otf were titrated into co2 saturated
solutions of mecn and lsvs were recorded with a bi - cmec coated gce .
each of these ils produces virtually identical polarization curves
with an onset potential for co2 reduction at approximately
1.8 v versus sce ( polarization curves for [ bmim]bf4 and [ bmim]otf are shown in figure s2 ) .
we note that this onset potential is nearly coincident with the equilibrium eco2/co potential ( 1.78
v ) under these conditions . as was observed
for [ bmim]pf6 ( vide supra ) , as the concentration of any
of the [ bmim ] salts increases , the co2 reduction
onset shifts to slightly more positive potential and the cathodic
response increases in magnitude .
this current response plateaus at
an il concentration of 300 mm in the catholyte solution . further
increasing
the concentration of any of the [ bmim ] salts
past this point did not yield larger gains in current density .
total current density . upon establishing that each
of the [ bmim ] salts that
we had screened could promote co2 activation by bi - cmec
in the absence of supporting electrolyte at an applied overpotential
( ) of less than 250 mv past eco2/co = 1.78 v , the stability and efficiencies
of these systems were assessed by controlled potential electrolysis
( cpe ) experiments .
these experiments were performed for co2 saturated solutions of mecn containing each of the [ bmim ] salts listed in table 1 using a bi - cmec modified
gce .
after initiation of the electrolyses at 2.0 v (
220 mv ) , the reaction headspace was periodically analyzed
by gas chromatography . for each of the [ bmim ] salts surveyed ,
co was the only gaseous product formed during the cpe experiments .
quantification of the co produced during these electrolyses afforded
the faradaic efficiencies ( fes ) for the 2e/2h reduction of co2 to co. these values are listed
in table 1 along with the calculated current
densities associated with co generation ( jco ) .
each of the ils surveyed displays excellent selectivities for
co production and jco values that range
from 17 to 30 ma / cm . as shown in figure 1b , current densities for co formation
were quite steady during
a 40 min cpe experiment for each il probed , suggesting that bi - cmec
is neither passivated nor degraded by any of the anions that were
surveyed .
importantly , control cpe experiments conducted in the absence
of either bi - cmec or co2 show negligible total current
densities ( jtot ) and do not produce appreciable
amounts of co ( figure 1b ) .
analysis of
the fe and jco values in
table 1 and figure 1b shows that cpe of co2 saturated solutions containing
the [ bmim ] halides resulted in conversion of co2 to co with the lowest efficiencies and slowest kinetics of the ils
surveyed .
this may be due to the fact that [ bmim]br and [ bmim]cl are
more hygroscopic than the other ils studied , as the presence of water
in the electrolyte solution may lead to the formation of other co2 reduction products such as formate , as has been shown previously .
by contrast , electrolyses conducted for the
bf4 , pf6 , and otf salts of [ bmim ] resulted
in fes for co production of 85% with impressive kinetics as
demonstrated by the high current densities for co generation of jco 25 ma / cm .
while
selectivity and current density are important metrics by
which any electrocatalyst is judged , energy conversion efficiency
is also a critical parameter in benchmarking electrocatalyst platforms
for renewable energy storage and/or fuel synthesis .
the cathodic half
reaction energy efficiency with which bi - cmec promotes the electrocatalytic
production of co from co2 ( co ) can be
determined by considering the fe for co formation , the equilibrium
potential of the co2/co redox couple under the cpe conditions
( eco2/co ) , and calculation
of the overpotential ( ) at which cpe is carried out . with these values in hand ,
the cathodic half reaction energy efficiency
of electrocatalytic co production by bi - cmec in the presence of each
of the imidazolium promoters listed in table 1 was calculated using eq 1.1except for the case of [ bmim]br , which shows
the lowest fe for co production , each of the ils studied promotes
the conversion of co2 to fuel with energy efficiencies
that are above 70% and the value for co approaches
80% for [ bmim]otf .
that [ bmim]otf promotes the reduction of
co2 to co with
such impressive efficiency and kinetics is notable , as this is one
of the least expensive commercially available [ bmim ] salts
with a current price of $2/g .
the theoretical maximum for
co2 reduction current density under aqueous conditions
is limited to 10 ma / cm by the relatively low solubility
of co2 ( 38 mm ) in water under ambient conditions . that the inexpensive bi - cmec platform in conjunction
with a [ bmim]/mecn catholyte gives rise to current densities
for co production of jco = 2530
ma / cm with attendant energy efficiencies that approach
co 80% is a significant achievement , as
there are virtually no materials other than precious metals that excel
in both these regards .
although
the bi - cmec platform that is deposited ex situ from concentrated
hcl is an excellent platform for electrocatalytic co production , the
in situ formation of this system from an mecn catholyte would simplify
preparation of this electrocatalyst and allow bi - cmec to be deposited
on substrates that are too delicate or reactive to tolerate the highly
acidic conditions required to electrodeposit bi - cmec from aqueous
solutions .
the in situ induced deposition of a bi - based material for
co2 electrocatalysis may be accomplished if reduction of
an organic soluble bismuth complex can be carried out at a potential
more positive than the onset potential for co2 reduction
and leads to precipitation of bi - cmec at the electrode surface .
although
most bi salts can be reduced at potentials that are more
positive than the 1.8 v required for co2 catalysis ,
the majority of such species are completely insoluble in the mecn
based catholyte required for co production .
organometallic bi(iii )
complexes such as [ bi(ph)3 ] can be supported
by the organic electrolyte employed in
the co2 reduction studies highlighted above ; however , this
neutral bi(iii ) derivative is only reduced at potentials that are
more negative than the onset potential for co generation by bi - cmec
( figure s3 ) , thereby precluding its use
as an in situ precursor of bi - cmec .
bismuth triflate ( [ bi(otf)3 ] ) represents a rare example of a bi salt that
is soluble in mecn .
having established that triflate salts do not
interfere with the electrocatalytic conversion of co2 to
co at bi - based cathodes ( vide supra ) , we rationalized that [ bi(otf)3 ] would be an attractive precursor for in situ bi - cmec electrodeposition .
to explore the possibility of co production by an in situ generated
bi - based electrocatalyst , we examined the electrochemical reduction
of mecn solutions containing bi and ionic liquid .
cyclic
voltammograms recorded for 1.0 mm [ bi(otf)3 ] and 300 mm
[ bmim]otf in co2 saturated mecn exhibit a cathodic feature
at e = 1.2 v , followed by the onset of an
intense catalytic wave at 1.8 v ( figure 2a ) .
this sharp rise in current is reminiscent of the polarization
curve observed for co2 electrocatalysis using an ex situ
generated bi - cmec modified gce ( figure 1 ) ,
suggesting that cathodic polarization of the mecn solution containing
[ bi(otf)3 ] leads to electrodeposition of a bi - based material
that can electrochemically activate co2 .
polarization experiments
conducted for mecn solutions containing 1.0 mm [ bi(otf)3 ] and 300 mm [ bmim]otf under an atmosphere of n2 are consistent
with this analysis . as shown by the blue trace in figure 2a , in the absence of co2 a large increase
in current
is not observed in the region from 1.8 to 2.1
v. similarly , voltammograms recorded in the absence of [ bmim]otf show
no catalysis , indicating that as was true for ex situ prepared bi - cmec ,
bi , co2 , and il are all integral to the observed catalysis .
( a ) cv
traces recorded at a gce in mecn solutions containing 1.0
mm [ bi(otf)3 ] under an atmosphere of either co2 or n2 .
inset : lsv trace obtained upon reduction of a
1.0 mm [ bi(otf)3 ] solution in mecn at a gce .
( b ) total
current density trace recorded for a ni disk electrode at 2.0
v in mecn containing 300 mm [ bmim]otf before and after addition of
1 mm [ bi(otf)3 ] .
inset : partial current density profiles
for co production ( jco ) at gce in mecn
containing 300 mm [ bmim]otf in the presence ( red ) and absence ( black )
of [ bi(otf)3 ] .
the strong catalytic wave observed under co2 at
potentials
more negative than 1.8 v in figure 2a prompted us to examine the activity of the in situ generated bi
material during a cpe experiment .
we employed a glassy carbon or nickel
working electrode to ensure negligible background activity for co2 catalysis .
as shown by the green trace in figure 2b , electrolysis of a co2 saturated solution
of mecn containing 300 mm [ bmim]otf at 2.0 v at a ni cathode
showed low current densities of jtot
1 ma / cm with no detectible co production .
upon addition
of [ bi(otf)3 ] to the electrolysis solution , a sharp rise
in current density was observed , ultimately leading to a steady state
value of 20 ma / cm .
this rise in current was accompanied
by formation of a dark electrodeposited coating on the working electrode
surface .
similar results were obtained upon electrolysis of a co2 saturated solution of mecn containing 1.0 mm [ bi(otf)3 ] and 300 mm [ bmim]otf at 2.0 v at a gce ( figure 2b red trace ) , indicating that in situ formation
of the electrodeposited bi catalyst can be accomplished using a variety
of conducting substrates .
periodic gc analysis of the reaction
headspace during the course
of the cpe experiment showed co to be the sole gaseous product formed
during the electrolysis experiment .
furthermore , quantification of
the amount of co produced during the cpe experiment corresponded to
a fe of 75% for the 2e/2h conversion
of co2 to co , with an average partial current density of jco = 5.0 0.9 ma / cm .
this
current density was stable for more than 3 h with no appreciable loss
in fe during the course of longer electrolysis experiments .
we note
that this system is extremely selective for co production , as no ch4 or h2 was detected during the cpe experiment .
using a combination of nmr methods
, we observed no coproduction of
formate , oxalate , or glyoxalate , which is often observed upon electrochemical
reduction of co2 in organic catholytes .
as such , the slightly reduced fe and jco values observed for the in situ bi - cmec system do not necessarily
point to an inherent deficiency of the catalyst but rather may be
the result of poorer ohmic contact between the electrocatalyst and
underlying gce , compared to when the bi - containing film is deposited
ex situ from aqueous acid .
losses due to resistance may be accompanied
by joule heating , as has been observed for au and ag catalysts for
co2 reduction .
additionally , the reduction in
fe under these conditions may be due to the small fraction of passed
current that is co - opted to drive [ bi(otf)3 ] reduction
during the in situ electrodeposition process .
repetition of
this cpe experiment under n2 leads to
little passed charge and no co production , indicating that the co
formed under an atmosphere of co2 is not simply a product
of il or solvent decomposition .
similarly , repeating this cpe experiment
under co2 but in the absence of [ bi(otf)3 ] leads
to low current densities ( 0.03 ma / cm ) and no co
production ( figure 2b , black trace ) . taken
together ,
these control experiments demonstrate that the il is integral
to the observed electrocatalysis , which is distinguished by high current
densities for the selective production of co over other reduced carbon
products or h2 . as such
, this system represents a rare
example of a co2 reduction electrocatalyst that can be
easily formed in situ from an inexpensive metal precursor .
to the
best of our knowledge , it is the first such system that operates in
an organic catholyte that supports the high concentrations of dissolved
carbon dioxide that are required for electrolytic co production with jco values in excess of 10 ma / cm .
the morphology and composition of the in situ generated bi - cmec
material were probed by a combination of physical methods .
scanning
electron microscopy ( sem ) revealed that the electrodeposited catalyst
consists of submicrometer - sized particles that have coalesced into
a film with a spongelike morphology ( figure 3a ) . the x - ray powder diffraction pattern obtained for this
material
is consistent with this amorphous morphology , largely showing broad
features and only small peaks indicative of crystalline bi ( figure 3b ) . in order to gain a greater understanding
of the elemental composition of the in situ generated bi - containing
material , energy - dispersive x - ray ( edx ) analysis
was performed on
40 40 m regions of several independently
prepared samples of the electrodeposited catalyst ( figure s4 ) .
the surface of the material was also analyzed
by x - ray photoelectron spectroscopy ( xps ) .
all elements detected by
edx are also accounted for by xps ( figure s5 ) , which identified bi , o , s , and f as the principal elemental components
and suggests that small amounts of triflate from the bi precursor are incorporated into the electrodeposited material .
consistent
with this assignment are the high - resolution xps spectra of the c
1s , f 1s , s 2s , and o 1s regions ( figures 3c and s5 ) .
integrating the small peak
in the c 1s spectrum at 292.7 ev ( corresponding to the carbon of a
cf3 group , such as that in triflate ) , the s 2s peak , the
f 1s peak , and a component for the lower binding energy peak in o
1s ( 530.1 ev ) , we find the ratio to be approximately 1:3:1:3 , respectively .
as such , the relative intensities of these components match the ratio
of c / f / s / o expected for a triflate anion . moreover , xps analysis of bismuth reveals bi 4f7/2 signals
at 157.1 and 159.5 ev , which are values typically observed for bi and bi , respectively ( figure 3d ) . on the basis of xps analysis of the in situ prepared bi - cmec
material , the ratio of bi to bi is 1:3 .
we note that electrodeposition of both bi and bi ions has been observed for bi - cmec films formed from concentrated
acidic solutions . when taken together ,
the edx and xps analyses indicate that in situ reduction of mecn solutions
of [ bi(otf)3 ] containing 300 mm [ bmim]otf leads to deposition
of a largely amorphous material containing metallic bi and bi ions that has incorporated a significant amount
of oxygen and small amount of triflate .
( a ) sem images of bi - cmec
electrodeposited on a gce from mecn containing
300 mm [ bmim]otf and 1.0 mm [ bi(otf)3 ] .
( b ) powder xrd
pattern showing the largely amorphous nature of in situ deposited
bi - cmec .
( c ) high - resolution c 1s and ( d ) bi 4f7/2 xps
spectra of in situ deposited bi - cmec .
the variation in partial current density associated with
co generation
for an in situ prepared bi - cmec on glassy carbon was measured as a
function of applied overpotential in co2 saturated mecn
containing 300 mm [ bmim]otf .
these data were obtained by performing
stepped potential electrolyses between e = 1.80
v and e = 2.3 v , with commensurate quantification
of the gaseous products by gc .
the fe for co production remains high
as the applied is increased ; however , the resulting tafel
plot constructed from these data ( figure 4a )
begins to deviate from linearity as the applied potential exceeds
2.0 v. this curvature is likely due to uncompensated ir drop caused by the surface resistivity of the gce along
with mass - transport limitations attendant to rapid co2 reduction
at the bi - cmec coated cathode .
it is expected that improved mass transport
using a flow cell , gas diffusion electrode , or other advanced cell
design would enable even higher current
densities ( tofs ) for co production using this system .
the tafel data
are linear in the range of = 0.020.17 v , with a slope
of 135 mv / decade .
this value is close to 118 mv / dec , suggesting that
initial electron transfer to generate a surface adsorbed co2 species is the rate - determining step
for co evolution .
the tafel slope observed for this material is in the same
range as that observed for co evolution using ex situ prepared bi - cmec
modified electrodes , suggesting that
both systems operate by analogous mechanisms .
( a ) partial current density
for co production ( jco ) tafel plot for
in situ generated bi - cmec with 300
mm [ bmim]otf in co2 saturated mecn .
( b ) polarization curves
recorded for several cathode materials for carbon dioxide reduction
show that under the conditions employed in this work , bi - cmec operates
with activity that is comparable to that of precious metals . on the basis of these stepped - potential
cpe and tafel results ,
it is clear that the in situ deposited bi - cmec operates with appreciable
current densities while maintaining impressive faradaic and energy
efficiencies at 200 mv .
the jco values obtained in this potential region correspond to an
average sustained activity for co production of 100 molcmh , a value that compares
favorably to that observed for conversion of co2 to co
using much more expensive ag based cathode materials . the efficiency and activity with which bi - cmec promotes
the electrochemical conversion of co2 to co
are highlighted
by comparing the polarization curves of several well studied cathode
materials for co2 reduction using an mecn/[bmim ] based catholyte .
as shown in figure 4b , bi - cmec
can activate co2 at significantly lower overpotentials
compared to other inexpensive cathode materials such as cu , zn , ni ,
and stainless steel ( ss ) and operates with kinetics and a cathodic
half reaction energy efficiency that are similar to those of au and
ag electrodes , which are much more cost prohibitive to prepare .
the development of efficient and robust
cathode materials that
can promote the rapid conversion of co2 to co is a key
step on the road to the storage and conversion of renewable energy
inputs to liquid carbon - based fuels .
although gold and silver catalysts
have long been known to be active platforms for this process , the
expense associated with use of these materials has precluded their
use on the scale required for electrolytic fuel production . by contrast
,
bismuth represents a poor metal that is environmentally benign and
extremely affordable .
both these factors make bismuth well positioned
for incorporation into co2 conversion and fuel production
schemes . in this work ,
we have shown that a bismuth based material
can be
formed under either aqueous or nonaqueous condition using versatile
electrodeposition methods .
this material can serve as a robust carbon
monoxide evolution catalyst and promotes the electrocatalytic reduction
of co2 to co in the presence of appropriate imidazolium
ionic liquid promoters .
this inexpensive bi - cmec platform tolerates
a variety of different catolyte anions including potentially corrosive
anions such as chloride and bromide .
most notably , bi - cmec promotes
the electrochemical generation of co from co2 with current
densities as high as jco = 2530
ma / cm and accompanying energy efficiencies for the cathodic
half reaction of co 80% .
both these values
compare extremely well to those observed using more expensive gold
and silver co2 reduction electrocatalysts and suggest that bi - cmec may be incorporated into an energy
efficient electrochemical device for fuel production if coupled to
an appropriate anodic half reaction . that bi - cmec can be easily prepared
at a small fraction of the price of these precious metal cathodes ,
which have historically been the most efficient platforms for electrolytic
production of co from co2 , represents a significant advancement
in the field of molecular energy conversion .
moreover , the rate of
co production by bi - cmec ranges from approximately 0.1 to 0.5 mmolcmh at an applied overpotential
of 250 mv for a cathode with surface area equal to
1.0 cm .
this co evolution activity is much higher than
that afforded by other non - noble metal cathode materials and distinguishes
bi - cmec as a superior and inexpensive platform for electrochemical
conversion of co2 to fuel .
in addition to being an
inexpensive and efficient platform for
co evolution , bi - cmec can also be easily prepared via an in situ electrodeposition
pathway . as such ,
the ease with which bi - cmec can be prepared complements
other types of co2 reduction catalysts that require the
presynthesis of metal nanoparticles or
electrode preparation using arc - melting processes .
the ability to electrodeposit the bi - cmec catalyst in situ
using a b precursor that is soluble in the co2 saturated catholyte solution significantly streamlines preparation
of electrode assemblies for co production .
this in situ formation
strategy has not commonly been employed for preparation of co2 reduction cathodes but offers significant advantages , as
it may facilitate catalyst deposition on a variety of substrates that
are too fragile to tolerate more traditional catalyst preparation
methods . as such
, we anticipate that the ability to easily prepare
bi - cmec via the in situ electrodeposition methods described herein
will prove especially beneficial for the construction of advanced
energy conversion devices and photoelectrochemical assemblies for
the conversion of solar energy to carbon - based fuels . | the development of inexpensive electrocatalysts
that can promote
the reduction of co2 to co with high selectivity , efficiency ,
and large current densities is an important step on the path to renewable
production of liquid carbon - based fuels .
while precious metals such
as gold and silver have historically been the most active cathode
materials for co2 reduction , the price of these materials
precludes their use on the scale required for fuel production .
bismuth ,
by comparison , is an affordable and environmentally benign metal that
shows promise for co2 conversion applications . in this
work ,
we show that a bismuth carbon monoxide evolving catalyst
( bi - cmec ) can be formed under either aqueous or nonaqueous conditions
using versatile electrodeposition methods . in situ formation of this
thin - film catalyst on an inexpensive carbon electrode using an organic
soluble bi3 + precursor
streamlines preparation of this
material and generates a robust catalyst for co2 reduction .
in the presence of appropriate
imidazolium based ionic liquid promoters ,
the bi - cmec platform can selectively catalyze conversion of co2 to co without the need for a costly supporting electrolyte .
this inexpensive system can catalyze evolution of co with current
densities as high as jco = 2530
ma / cm2 and attendant energy efficiencies of co 80% for the cathodic half reaction .
these metrics
highlight the efficiency of bi - cmec , since only noble metals have
been previously shown to promote this fuel forming half reaction with
such high energy efficiency .
moreover , the rate of co production by
bi - cmec ranges from approximately 0.10.5 mmolcm2h1 at an applied overpotential
of 250 mv for a cathode with surface area equal to
1.0 cm2 .
this co evolution activity is much higher than
that afforded by other non - noble metal cathode materials and distinguishes
bi - cmec as a superior and inexpensive platform for electrochemical
conversion of co2 to fuel . |
reliable information about health status of the community is the prerequisite for planning of service . under national health mission preparation of district health action plan ( dhap ) with present status
large scale survey using tool seeking the peoples view on various aspects of health is a common practice .
indicators like disability - adjusted life years and disability - adjusted life expectancy are probably the best indicators evolved .
usually , managers resort to some traditional indicators that have varied reliability and validity and provide information about specific aspects of health . like human development index
, comprehensive health index may be obviously very informative and desired . such index will help to compare the districts and allocate resources to the area proportionate to the index .
the region wise compiled information dilutes the actual situation in the districts , hence , the district - wise analysis is best tool . unfortunately , district - wise data of reasonable reliability are seldom available excepting district level household survey ( dlhs ) and annual health surveys ( in selected states )
. health management information system ( hmis ) also provides information . an attempt is made here to develop a comprehensive index from available data sources for a district and use it for measurement of district wise disparity .
this fact has been confirmed even in human development report published by government of maharashtra in 2012 . in that report
all the districts below median were from marathwada and vidarbha ( excepting two which are tribal districts ) .
conventionally , therefore , any status and progress in the state is compared between marathwada , vidarbha , and rest of the maharashtra state ; although the rest of the area of maharashtra state is a very heterogeneous group of population . in each division
there are 35 districts inclusive of two districts of mumbai municipal corporation , which are not considered in the study .
the sources included hmis of directorate of health services , cause of death survey conducted by directorate of health services , dlhs 3 maharashtra , published or unpublished studies , internet , and so on .
hmis in maharashtra state is well established and acknowledged system since 19821983 and was considered comparable to other data sources .
district wise reliable data about few indicators like number of cancer cases , risk factors like tobacco consumption and so on was not available . wherever there was more than one source ,
the latest available statistics were considered ( excepting immunization coverage for which data from dlhs 3 was used ) .
the list 68 indicators was first discussed and consensus arrived among multispecialty experts in economics , education , and administration , including senior most public health specialist from society for education , action and research in community health ( search ) gadchiroli in series of meetings for determining priority .
then two senior public health specialists who have worked as professor in community medicine have been consulted for finalizing the list .
all the indicators excluding demographic were classified into following four categories health outcomes , health systems , other determinants of health , and utilization of services slightly different from conventional way .
it was also agreed that there will be scoring system having 1000 marks and limit the indicators to 10 for easy calculation .
it was also decided to allocate 40% weightage to health outcomes , 30% to health system , 20% to other health determinants , and 10% to utilization of services .
infant mortality rate ( imr ) , maternal mortality ratio ( mmr ) , total fertility rate ( tfr ) , proportion under five children having malnutrition , doctor population ratio , nurse population ratio , bed population ratio , proportion of water contamination , age at marriage for girls , and proportion of fully immunized infants were considered for inclusion .
maximum 100 marks were allotted for each indicator . for each indicator the district having best value
correlation coefficients between comprehensive index and proportion of tribal population , per capita income , and female literacy rate were calculated .
this fact has been confirmed even in human development report published by government of maharashtra in 2012 . in that report
all the districts below median were from marathwada and vidarbha ( excepting two which are tribal districts ) .
conventionally , therefore , any status and progress in the state is compared between marathwada , vidarbha , and rest of the maharashtra state ; although the rest of the area of maharashtra state is a very heterogeneous group of population . in each division
there are 35 districts inclusive of two districts of mumbai municipal corporation , which are not considered in the study .
the sources included hmis of directorate of health services , cause of death survey conducted by directorate of health services , dlhs 3 maharashtra , published or unpublished studies , internet , and so on .
hmis in maharashtra state is well established and acknowledged system since 19821983 and was considered comparable to other data sources . the investigator collected information of 68 indicators .
district wise reliable data about few indicators like number of cancer cases , risk factors like tobacco consumption and so on was not available . wherever there was more than one source ,
the latest available statistics were considered ( excepting immunization coverage for which data from dlhs 3 was used ) .
the list 68 indicators was first discussed and consensus arrived among multispecialty experts in economics , education , and administration , including senior most public health specialist from society for education , action and research in community health ( search ) gadchiroli in series of meetings for determining priority .
then two senior public health specialists who have worked as professor in community medicine have been consulted for finalizing the list .
all the indicators excluding demographic were classified into following four categories health outcomes , health systems , other determinants of health , and utilization of services slightly different from conventional way .
it was also agreed that there will be scoring system having 1000 marks and limit the indicators to 10 for easy calculation .
it was also decided to allocate 40% weightage to health outcomes , 30% to health system , 20% to other health determinants , and 10% to utilization of services .
infant mortality rate ( imr ) , maternal mortality ratio ( mmr ) , total fertility rate ( tfr ) , proportion under five children having malnutrition , doctor population ratio , nurse population ratio , bed population ratio , proportion of water contamination , age at marriage for girls , and proportion of fully immunized infants were considered for inclusion .
maximum 100 marks were allotted for each indicator . for each indicator the district having best value
correlation coefficients between comprehensive index and proportion of tribal population , per capita income , and female literacy rate were calculated .
a tribal district has lowest index ( 0.36 ) and a nontribal district has highest value ( 0.66 ) .
there is negative correlation [ r = -0.73 ; 95%confidence interval ( ci ) = -0.37 to -0.90 ] between proportion of tribal population and comprehensive index .
there is positive correlation ( r = 0.65 ; 95% ci = 0.400.81 ) between comprehensive index and per capita income and also between comprehensive index and female literacy rate ( r = 0.71 ; 95% ci = 0.490.85 ) .
gadchiroli , washim , and nagpur from vidharbha topped the list in one indicator each .
sindhudurg district from rest of maharashtra has the distinction of appearing twice in best performance .
the division wise distribution of districts appearing in first ( lowest quartile ) and fourth quartile ( best quartile ) is depicted .
all the districts excepting two in lower quartile are from marathwada and vidarbha , whereas all the districts excepting two in upper quartile are from rest of maharashtra .
selection of three indicators monitored under nrhm was imperative , as they are accepted valid for health outcomes .
the child malnutrition has always been a hot topic for health professional , press , and politicians in maharashtra .
second reason for its inclusion was to cover child health after infancy period over . among the health determinants
three most standard indicators of health system were given highest weightage pondering a separate category .
the whole purpose of creation of resources is to transform the health system and bring out positive changes in the health status .
the mean age at marriage for girls is one of the strong determinants of maternal health . although there is an act prohibiting marriage before 17 years for girls , child marriages are rampant in maharashtra . among health determinants
income and education were considered only for validity check and the correlation is as anticipated . by their inclusion
the last indicator is one of the determinants of first indicator which itself is considered appropriate and sensitive indicator of health of the community .
the investigator agrees that the selection of indicators is skewed toward maternal and child health sector . in india
even the report from united states on health disparities and inequalities includes health outcomes in the form of morbidity and mortality covers , social determinants , and health care access and preventive services like present study .
united states report also includes environmental hazards and behavioral - risk factors , which are surely locally relevant . in this study proportion of tribal population has emerged is strong impediment for health status . among notified tribal districts the proportion of tribal population varies from 3.7% in pune district to 69.3% in nandurbar district and the index
the left wing extremist insurgency may be one of the reasons for lagging behind . in maharashtra
an earlier committee laid emphasis on infrastructure alone , converting the gap into financial implications .
the committee considered all the districts having figured less than state average as districts having backlog resulting into a large scope requiring special attention .
comprehensive index may certainly help in assessment of overall health status , measure disparity and provide technical , and managerial robust tool to initiate measures for improvement through dhap .
| background : health administrators require status of health of different administrative units under them
. use of large number of indicators may create confusion and uncertainty about health status .
availability of a comprehensive index is certainly useful.objective:to evolve one comprehensive health index for a district as unit and measure district wise disparity.materials and methods : ten indicators from categories of health outcomes , health system , determinants of health , and utilization of services were considered .
data for districts in maharashtra state were obtained from different sources.for each indicator the best performing district was given score of 100 and other districts were given marks proportionately.results:the comprehensive index for the state was 0.52 .
the district scoring lowest value of 0.36 was a tribal district and scoring highest value of 0.66 was a nontribal district.conclusion:computing such index of districts for monitoring and allocation of resources may be useful managerial tool . |
obesity refers to excessive adipose tissue accumulation and is defined by the world health organization ( who ) as a body mass index ( bmi : weight ( kg)/length ( m ) ) greater than or equal to 30 .
obesity has been declared a major health problem and its incidence has more than doubled worldwide since 1980 with over 200 million men and nearly 300 million women being classified as obese in 2008 according to the who .
obesity is associated with numerous adverse health consequences , including type 2 diabetes , insulin resistance , hypertension , cardiovascular disease , and certain cancers [ 2 , 3 ] .
the direct costs associated with obesity were estimated to account for between 0.7% and 2.8% of a country 's total healthcare expenditures with medical costs of obese individuals being approximately 30% greater than their normal weight peers .
thus , social and economic costs related to obesity in developed countries are now well recognized .
it has been reported that the current intervention strategies to prevent and manage obesity and its associated diseases are limited to postnatal life with focus on exercise , salt intake , dietary interventions , and smoking cessation .
these interventions have limited success and it is not surprising that the battle against obesity and its associated diseases particularly in wealthy industrialized countries is currently being lost . gluckman and hanson suggest that it is important to refocus on maternal health and nutrition issues during pregnancy , which are now considered to play a major role in the onset of obesity . in this review
we summarize epidemiological and animal studies linking adverse in utero environments , particularly iugr , to postnatal adipose tissue accumulation .
we also highlight potential mechanisms underlying links between iugr and the long - term adipose tissue expansion and emphasize some ideas for further research in iugr models .
the term programming in the broad sense was suggested by lucas , to name the process by which a stimulus or insult during critical periods of life results in long - term consequences such as induction , deletion , or impairment of a somatic structure or alteration of a physiologic function .
earlier animal experiments reported the early environment to be a major determinant of growth and form .
human cohort studies also reported an inverse association between birth weight and systolic blood pressure in 36-year - old men .
it was in the early 80s that the fetal programming and early life origins of adult diseases concepts as proposed by david barker and colleagues really began to cement the importance of the in utero environment .
barker and colleagues proposed that environmental factors , particularly nutrition , act in early life to program the onset of cardiovascular disease in early adult life and premature death as the consequence .
this association has been postulated to be an adaptive response to a suboptimal fetal environment protecting the growth of key organs such as brain to the detriment of others such as liver and resulting in an altered postnatal metabolism .
these adaptations , termed the thrifty phenotype , serve the purpose of enhancing prenatal survival under conditions of intermittent or poor nutrition . however when nutrition is more abundant in the postnatal environment than in the prenatal environment , the changes adopted by the fetus before birth may lead to a nutritional mismatch between energy intake , storage , and expenditure , resulting in a subsequent increase in disease risk .
fetal programming is a concept that thus identifies in utero environmental conditions as key determinants for the increased risk of diseases later in life .
epidemiological observations as well as clinical and animal studies worldwide support the concept of fetal programming as the origin of a number of diseases including obesity , insulin resistance , and noninsulin - dependent diabetes [ 1215 ] . specifically , the early life origins of obesity concept has led to the hypothesis that exposure to excessive or deficient nutrition before birth alters the development of the fat cell , the adipocyte , in utero and results in a permanent increase in the capacity to form new cells in adipose depots or to store lipid in existing adipocyte in postnatal life .
two types of adipose tissue , white adipose tissue ( wat ) and brown adipose tissue ( bat ) , coexist in most mammalian species .
wat has an essential role in energy storage by providing long - term fuel reserve in the form of triacylglycerols , which can be mobilized during food deprivation with the release of fatty acids for oxidation in others organs .
bat , on the other hand , is specialized in the dissipation of energy through the production of heat .
the wat is made up of unilocular adipocytes , which contain a single large lipid vacuole that pushes the cell nucleus against the plasma membrane .
the biogenesis of white adipocytes comprises the generation of committed adipocyte precursors ( or preadipocytes ) and the terminal differentiation of these preadipocytes into mature functional adipocytes .
this is accompanied by the expression of adipogenic and lipogenic transcription factors including peroxisome proliferator - activated receptor- ( ppar ) , ppar , ccaat / enhancer binding proteins ( c / ebp , , ) , and the sterol regulatory element - binding protein 1 ( srebp1 ) and the expression of specific lipid - metabolizing enzymes such as fas [ 2226 ] .
these transcription factors appear to be part of a cascade in which ppar is the master regulator with its activity modulated by selecting corepressors and coactivators including src1 ( steroid receptor coactivator 1 ) , sirt1 ( an nad - dependent histone deacetylase and chromatin - silencing factor ) , ncor ( nuclear receptor corepressor ) , and smrt ( silencing mediator for retinoid and thyroid hormone receptor ) [ 27 , 28 ] . following this gene regulation cascade , the adipogenesis process ends with the establishment of the endocrine function characterised by the production of the adipocyte - specific hormone , leptin .
leptin circulates at levels proportional to body fat and acts on the central nervous system to regulate energy intake and expenditure , through binding with neuropeptide y ( npy ) neurons producing a feeling of satiety . in mammals
, wat is distributed unevenly through the body and is represented by two main fat depots , which are defined by their location : subcutaneous and visceral . in humans ,
subcutaneous depots consist of adipose tissue under the skin in primarily the buttocks , thighs , and abdomen .
visceral adipose tissue depots include the mesenteric , omental , perirenal , retroperitoneal , and pericardial fat stores . in sheep , a large animal model of adult onset obesity
, wat is present in the omental , subcutaneous and hindlimb regions [ 3234 ] .
wat depots in rodents ( rats and mice ) , exist in two main subcutaneous fat depots , one anterior and one posterior , lying in discrete anatomical sites .
the anterior depot is complex , occupying the dorsal body region between and under the scapulae , the axillary and proximal regions of forelimbs , and the cervical area .
the posterior depot is located at the base of hind legs and at dorsolumbar , inguinal , and buttock regions .
the visceral adipose depots similarly to humans , are located in thoracic and abdominal cavities : mediastinic , mesenteric , retroperitoneal , perirenal , and perigonadal depots .
the second type of adipose tissue , the bat , is specialized in the dissipation of energy through the production of heat .
it is characterised by having a dark color compared to wat , which arises from its vascularization and numerous mitochondria [ 36 , 37 ] and appears to have a denser nerve supply than wat . in bat ,
multilocular adipose cells usually contain many small vacuoles of lipid and large mitochondria with closely packed parallel cristae [ 39 , 40 ] , where the uncoupling protein 1 ( ucp1 ) is highly expressed and is regarded as a bat - specific marker . in conjunction with ucp1 , a number of other genes including type 2 iodothyronine deiodinase , the transmembrane glycoprotein elovl3 , the fatty - acid - activated transcription factor peroxisome proliferator - activated receptor- ( ppar ) , the nuclear coactivator peroxisome proliferator - activated receptor- coactivator 1 ( pgc-1 ) , and developmental homeobox genes hoxa1 and hoxc4 are preferentially expressed in bat [ 37 , 42 ] . by way of comparison , expression of leptin ,
the nuclear corepressor rip140 , matrix protein fibrillin-1 , and developmental human genes hoxa4 and hoxc8 in bat are low compared to their greater expression observed in wat [ 37 , 42 ] .
it has long been assumed that white and brown adipocytes share a common developmental origin and also undergo a very similar program of morphological differentiation controlled by ppar and members of the c / ebp family of transcription factors .
however , recent studies indicate that brown adipocytes arise from tripotent engrailed-1-expressing cells in the central dermomyotome through a dynamic involvement of the prd1-bf-1-riz1 homologous domain - containing protein-16 ( prdm16 ) [ 43 , 44 ] . in addition , prdm16 coactivates the transcriptional activity of pgc-1 , pgc-1 , ppar , and ppar through direct interaction and thus drives preadipocytes development into brown adipocytes .
this differential origin is probably determinative for the evolutionary role of bat and wat in mammals . in the human fetus and newborn ,
bat is located mainly in the cervical , axillary , perirenal , and periadrenal depots [ 45 , 46 ] and plays an important role in nonshivering heat production during neonatal life and thus provides protection against lethal cold exposure ( hypothermia ) . in adults ,
the depots of bat are found in a region extending from the neck to the thorax , especially in interscapular , supraclavicular , cervical , axillary , and paravertebral regions [ 47 , 48 ] and these depots are now understood to be associated with body weight regulation . in comparison ,
bat in rodents is located mainly in the upper back region ( interscapular bat ) and first appears during the last days of gestation , matures during the neonatal period , and remains at a relatively stable level for the life span of animals .
bat is also visible in the subcutaneous anterior depot and mediastinic and perirenal sites in adult rodents maintained in normal conditions . in other species ,
for example , lambs are born with almost 100% bat [ 52 , 53 ] , with majority of this adipose tissue located around the kidneys [ 33 , 34 ] .
postnatally in young life , bat localization becomes the sternal , clavicular , pericardial , and epicardial depots in addition to the perirenal depot .
adipocytes in wat are generally described to be derived from mesenchymal stem cells ( mscs ) .
these themselves are thought to arise from mesoderm , although an alternative source of mscs , as well as adipocytes , from the neural crest has recently been demonstrated .
adult adipose tissue develops as a continuous process ; however , prenatal adipose tissue formation can be divided into five morphogenic phases strongly associated with the formation of blood vessels ( figure 1 ) .
these five stages include ( 1 ) the emergence of loose connective tissue , ( 2 ) proliferation of primitive vessels associated with mesenchymal condensation , ( 3 ) mesenchymal cells differentiating into stellate preadipocytes within a vascular structure or glomerulus , ( 4 ) appearance of fine fat vacuoles in cell cytoplasm of mesenchymal lobules , and ( 5 ) fat lobules well separated from each other by dense septae of perilobular mesenchymal tissue .
fat lobules are the earliest structures to be identified before the appearance of typical vacuolated fat cells . in humans ,
white fat lobules appear first in the face , neck , breast , and abdominal wall at 14 weeks gestation . by 15 weeks , they are also evident over the back and shoulders and further development of white fat lobules in the upper and lower extremities and anterior chest begins around this time .
after the 23rd week , the total number of fat lobules remains approximately constant , while from the 23rd to 29th week , the growth of adipose tissue is determined mainly by an increase in size of the fat lobules . in comparison , three distinct stages of prenatal wat differentiation are postulated in rats . in stage 1 , a sparse network of large capillaries develops . in stage 2 ,
most of cells are spindle - shaped cells and surrounding connective tissue contains very few blood vessels followed by capillary bed formation .
the earliest embryonic subcutaneous adipose cells are detected at days 15 - 16 of gestation ( length of gestation ~2123 days ) .
perirenal adipose tissue in rat appears mainly around birth , that is , 12 hours before and after birth .
only two to five days separate the formation of first perirenal adipose cells and the appearance of mesenteric fat cells that develop the last . as a consequence ,
minimal amounts of adipose tissue ( 1% ) are deposited prior to birth and maturation of this tissue primarily occurs postnatally . in rats the brown adipocyte precursors are parenchymal spindle cells closely related to a network of capillaries .
as the cells and vessels proliferate , they are organized into lobules by connective tissue septa . when the cells start accumulating lipid , they initially are unilocular , but with further lipid accumulation , multiple cytoplasmic lipid vacuoles appear .
bat formation takes place in the scapula of rats between day 15 to 17 of gestation [ 60 , 61 ] and is present throughout life .
human studies are not as specific as in rats ; however studies suggest that fetal bat is observed in the cervical , thoracic , and abdominal viscera and at the shoulder girdle and neck at approximately 23 weeks of pregnancy . in the postnatal environment ,
expansion of adipose tissue occurs mainly after birth through increases in adipocyte size and enlargement of adipose capillaries ( figure 1 ) under the actions of enzymes such as lipoprotein lipase , a regulator of adipocyte lipid filling [ 63 , 64 ] .
adipocyte hyperplasia following birth appears limited ; however studies do report its activation for the renewal of adipocytes suggesting that wat and bat in humans , as well as in rodents , still contain precursor cells capable of differentiating into adipocytes at adulthood [ 6668 ] .
iugr or fetal growth restriction ( fgr ) which refers to a fetus that fails to meet its genetic growth potential , is characterized by a weight at or below the 10th percentile for gestational age and affects approximately 715% of pregnancies worldwide .
the association between iugr and the postnatal development of obesity has been reported in human epidemiological studies and in animal models [ 70 , 71 ] and their interaction is postulated to be a major contributor to the current global obesity epidemic [ 5 , 70 ] .
a number of animal models have been developed to examine the effects of in utero insults such as maternal undernutrition and placental insufficiency on the long - term adipose tissue expansion and function . in the frequently used rodent maternal low - protein model ( 50% protein restriction during gestation ) ,
iugr and subsequent obesity have been reported [ 14 , 7275 ] . while protein restriction in pregnancy itself is sufficient to lead to obesity , this effect is enhanced by overfeeding during the suckling , proving the concept of the nutritional mismatch [ 7476 ] .
further , maternal undernutrition as a nutritional manipulation is characterized by a global dietary restriction during pregnancy and also results in low weight at birth and later obesity in rats . in pigs , low protein diet ( 6% protein versus 12% ) throughout pregnancy results in decreased body weight of piglets at birth and increased wat percentage at 188 days of age .
moreover , iugr occurs spontaneously in pigs and these low - birth - weight piglets also display significant higher body fat at 12 months compared to normal - birth - weight piglets , highlighting common mechanisms at play between a reduced protein supply in utero and a reduced placental exchange capacity as occurs in spontaneous iugr .
in addition , placental insufficiency results in reduced birth weight , increased early postnatal growth , and increased visceral adiposity in adolescent sheep and in young and adult rat offspring [ 81 , 82 ] .
the idea that bat deposition may change in response to suboptimal in utero environment as iugr and that this adaptation is perpetuated through the life cycle , thereby suppressing energy expenditure and ultimately promoting later obesity , is currently emerging . in the sheep model ,
placental restriction alters feeding activity , which increases with decreasing size at birth and is predictive of increased postnatal growth and adiposity including the perirenal adipose tissue , a depot that displays characteristic of bat in young sheep .
prenatal nutrition regulates bat development as studied in fetuses from arginine - treated underfed ewes compared with fetuses from saline - treated underfed ewes .
existing data indicate that nutrient availability during the intrauterine life , independently of fetal growth , determines bat development and the control of energy utilization during postnatal life period .
indeed , it has been demonstrated that feeding pregnant mice with the low - protein diet throughout gestation results in an unchanged bat mass and a significantly increased expression of ucp1 in interscapular brown adipose tissue in adult female offspring when compared to normal offspring .
it should be noted that in this study , the protein restricted offspring did not display a reduced fetal growth or low birth weight .
in contrast , in a female rat offspring born with normal weight , the intrauterine malnutrition resulted in lower bat deposition accompanied with an increased wat adiposity at 53 days of age .
the programming of bat is therefore an exciting area that warrants further studies into the effects of iugr or low birth weight upon postnatal bat growth and metabolism . the first studies addressing low birth weight as a result of fetal growth restriction leading to the subsequent expansion of adipose tissue in adults utilised data obtained from the studies of the offspring born following the dutch famine of 1944 - 1945 .
exposure to the famine during the first half of pregnancy resulted in low birth weight and this was significantly associated with higher obesity rates and more truncal and abdominal fat distribution in men at 19 years of age .
a subsequent study of this cohort reported a higher bmi and waist circumference in 50-year - old women exposed to the famine in early gestation ( first trimester ) compared to nonexposed women .
the association between low birth weight and later adiposity is also highlighted by studies in a biethnic population ( mexican - american and non - hispanic white ) in the united states . in these studies ,
normotensive and nondiabetic adult individuals whose birth weight was in the lowest tertile have a significantly greater truncal fat deposition pattern ( + 14% , measured through the subcapsular - to - triceps skinfold ratio ) than individuals whose birth weight was in the highest tertile independently of sex , ethnicity , and current socioeconomic status .
animal and human studies have focused on several intrauterine mechanisms that may program the fetal adipose tissue for later obesity .
specifically , changes in fetal adipose tissue morphology and metabolism , altered pathways regulating appetite , and modification of hormone levels and epigenome in the fetus have been highlighted as critical regulators in the development of obesity following iugr ( figure 2 ) .
emerging evidence from animal studies indicates that an increased prenatal adipocyte differentiation and lipogenesis likely promotes the development of later obesity in iugr offspring [ 28 , 89 ] .
such effects imply an early induction of adipose ppar activity concomitantly with an upregulated expression of its coactivator src1 and its downstream regulatory transcriptional factors ( cebp , , , and the retinoid x receptor ) and a downregulation of hormone - sensitive lipase ( hsl ) , an enzyme favouring adipocyte lipid release [ 28 , 90 ] . in pigs , metabolic pathways have been identified that underlie early subcutaneous adipose tissue adaptation to prenatal maternal low - protein diet and cause later fattening phenotype .
these data indicate that maternal diet restriction during gestation leads to iugr , affects fetal adipose tissue development and programs its later phenotype . in these experiments
, 1-day - old piglets prenatally exposed to low - protein diet displayed an upregulation of proteins involved in the conversion of glucose into fatty acids ( e.g. , transaldolase 1 , aldolase c , enolase 1 , and pyruvate dehydrogenase ) as well as an increased fas activity in subcutaneous adipose tissue .
in addition , a decreased insulin - like growth factor 1 mrna expression has been demonstrated in perirenal visceral adipose tissue from placental restriction in sheep fetuses at day 145 of gestation , which may alter adipocyte proliferation and differentiation , increasing their susceptibility for increased visceral adipose tissue in later life .
moreover , an increased abundance in the expression of genes , involved in adipogenesis ( e.g. , cebp- , - , and fas ) and angiogenesis ( e.g. , leptin tgf-1 , ctgf , cyr61 , dermatopontin , and chymase-1 ) in adipose tissue ( figure 1 ) as molecular mechanisms that underlie the early programming of later increased visceral adiposity in rats by maternal protein restriction , has been reported .
these data emphasize the involvement of prenatal adipose tissue development in later life adult obesity .
it is however necessary to note that although an altered metabolism and morphology of adipose tissue during fetal life participates as a mechanism in later obesity related to iugr , rapid postnatal catch - up growth is also a contributor in such increased adiposity [ 74 , 75 ] . indeed ,
prenatal growth trajectory in conjunction with rapid growth in early infancy ( catch - up growth ) must be considered to ultimately determine the origins of later diseases such as obesity .
leptin , a 16 kda protein hormone , stimulates a negative energy balance by increasing energy expenditure and reducing food intake .
leptin mainly acts by binding to specific central and peripheral receptors in the hypothalamus , adipose tissue , liver , and pancreatic -cells .
studies have highlighted the importance of prenatal leptin in developmental programming of adipose tissue and several human studies have reported that fetal serum leptin levels are lower in iugr babies [ 98101 ] .
thus , leptin may play a role in the control of substrate utilization and in the maintenance of fat mass before birth , producing permanent changes resulting in adiposity in adulthood [ 102 , 103 ] .
supporting this idea , it has been demonstrated that neonatal leptin treatment of iugr piglets and pups reverses high level of fetal cell proliferation in adipose tissue induced by iugr as well as the associated later increased adiposity [ 104 , 105 ] .
it is possible that in iugr , the underlying mechanisms of in utero leptin action in the developing susceptibility to adult obesity are alterations of the expression of appetite stimulating neuropeptides , such as npy in the fetal brain , alterations in adipose sympathetic innervations , as well as an altered hypothalamic leptin receptor ( obrb , obese receptor b ) expression and partitioning among the different hypothalamic nuclei .
indeed , obrb , which is preferentially localized in the arcuate nucleus ( arc ) in animals with normal body weight , was found to be almost equally distributed between arc and paraventricular nuclei ( pvn ) in iugr newborn piglets . in addition , a lower expression of obrb in the arc of iugr versus control piglets was observed suggesting a lower sensitivity to leptin action in iugr leading to altered food intake behaviour and subsequent obesity . in line with that data , leptin administration in both pregnancy and lactation has been shown to provide long - term protection from early maternal low - protein - associated obesity in rats .
the hypothalamo - pituitary - adrenal ( hpa ) axis has been proposed to participate in the pathophysiology of later life obesity following being born iugr .
the mechanisms are ill defined , but evidence from animal studies suggests that adverse events in early life may influence the neuroendocrine development of the fetus resulting in long - term alterations in the setpoints of several major hormonal axes , including an increase in adrenal glucocorticoid secretion .
indeed , the adipose tissue from early nutrient - restricted sheep fetuses displays alterations in glucocorticoid signalling ( increased glucorticoid receptor and 11--hydroxysteroid dehydrogenase 1 ( 11-hsd1 ) expression , but decreased 11-hsd2 abundance ) at day 140 of gestation and at 6 months postnatally .
as 11-hsd2 converts cortisol to its inactive metabolite cortisone and is thought to protect certain tissues from excess cortisol exposure , these results suggest that glucocorticoid action may be enhanced in offspring exposed to nutrient restriction in utero , thereby increasing their susceptibility to later obesity .
thus , it has been suggested that this in utero increased adipose glucocorticoid sensitivity observed near term in maternal nutrient - restricted sheep fetuses , may subsequently lead to the pathophysiological development of visceral obesity in later life by triggering the acquisition of white adipose tissue characteristics postnatally .
low levels of dna methylation , particularly at gene promoter regions , have been proposed to generate active genes .
is established early in development , during a window in which environmental insults such as in utero stress are able to influence developmental trajectories , altered epigenetic regulations are therefore mechanisms which could underlie programmed adiposity in the offspring .
the study of altered chromatin structure in iugr , as it relates to later life obesity , is a new and rapidly evolving field . in maternal low - protein animal models of later life obesity ,
alterations of the methylation status in the promoter of metabolic genes , such as hepatic ppar , glucocorticoid receptor ( gr ) , and liver x receptor ( lxr ) and hypomethylation of leptin promoter in adipose tissue have been reported during fetal and postnatal life , highlighting the importance of in utero environment as a predeterminant of later life chromatin function . in human studies ,
investigations of blood samples from the dutch hunger winter cohort at the age of 60 years , report an increased dna methylation induced by periconceptional exposure to the famine in genes known to be involved in adipose tissue metabolism , specifically leptin and the fat mass and obesity associated gene ( fto ) suggesting a possible suppression of its activity .
indeed , modifications in fto gene expression are reported to modulate tissue lipid metabolism , and content [ 118 , 119 ] as well as lipotoxicity and may be mediated by changes in energy balance at any stage of fetal development .
this paper provides a frame work for how adipogenesis and lipogenesis processes may be altered in iugr and low birth weight , setting the stage for obesity later in life .
it presents evidence from both animal and human studies indicating that an increased lipogenic and adipogenic capacity of adipocytes , hypoleptinemia , altered glucocorticoid signalling , and epigenetic modifications during fetal life likely play major roles in the in utero origins of later life obesity .
given that discrete molecular changes in fetal adipose tissue have been shown to adversely affect adipose tissue development of iugr individuals later in life , there is a real need to undertake longitudinal studies ( before birth , during early postnatal life , and adulthood ) on adipose tissue development and establish definitively which genes and pathways in this tissue have a causal role in the in utero origins of obesity . | intrauterine growth restriction ( iugr ) is strongly associated with obesity in adult life .
the mechanisms contributing to the onset of iugr - associated adult obesity have been studied in animal models and humans , where changes in fetal adipose tissue development , hormone levels and epigenome have been identified as principal areas of alteration leading to later life obesity . following an adverse in utero development , iugr fetuses display increased lipogenic and adipogenic capacity in adipocytes , hypoleptinemia , altered glucocorticoid signalling , and chromatin remodelling , which subsequently all contribute to an increased later life obesity risk .
data suggest that many of these changes result from an enhanced activity of the adipose master transcription factor regulator , peroxisome proliferator - activated receptor- ( ppar ) and its coregulators , increased lipogenic fatty acid synthase ( fas ) expression and activity , and upregulation of glycolysis in fetal adipose tissue .
increased expression of fetal hypothalamic neuropeptide y ( npy ) , altered hypothalamic leptin receptor expression and partitioning , reduced adipose noradrenergic sympathetic innervations , enhanced adipose glucocorticoid action , and modifications in methylation status in the promoter of hepatic and adipose adipogenic and lipogenic genes in the fetus also contribute to obesity following iugr .
therefore , interventions that inhibit these fetal developmental changes will be beneficial for modulation of adult body fat accumulation . |
leptospirosis continues to be a significant threat to food producing animals ; in 2010 of the 8,681 suspected serum samples examined in the uk by the animal health and veterinary laboratories agencies ( ahvla ) 2,946 were identified as being seropositive for leptospira .
approximately 59% ( 1736 ) of these seropositive samples were derived from dogs and the majority of these ( 69% ) were positive for serovar canicola , which to date has not been fully characterised using genomics or proteomics . whilst the mortality rate associated with leptospirosis remains low , due to its susceptibility to antibiotics and the routine vaccination of domestic and farm animals , initial clinical signs such as cessation of milk production and miscarriage
vaccination represents an effective treatment strategy for prevention of the disease ; however the vaccines currently available are all serovar specific .
serological methods for identification of leptospira serovars , such as the microscopic agglutination test ( mat ) , are well established . whilst being effective these are extremely time consuming and require access to a large leptospira strain / antiserum collection , to which many third world countries do not necessarily have access ; this in conjunction with the limited public profile of leptospirosis often leads to misdiagnosis and general under reporting of infection .
in addition false positive results using the mat have been reported due to the prior vaccination of test subjects .
genetic classification systems for l. interrogans are not routinely utilised as genetically different species are often found to be serologically identical which leads to poor reproducibility with the mat [ 5 , 7 ] .
protein based diagnostic elisas for the detection of leptospira have been reported previously [ 810 ] ; however the development of a routine protein based test for the taxonomic classification of the various serovars has yet to be developed .
it is conceivable that characterisation and cross comparison of the protein content of the different serovars might unveil serovar specific protein markers which could be developed into a routine diagnostic test ( such as an elisa ) to replace the mat and track the epidemiology of the bacteria more accurately .
however to date only serovars copenhageni [ 1115 ] , pomona , and lai [ 17 , 18 ] have had their proteomes characterised . in addition improved epidemiology of the bacteria , through the development of a routine protein based elisa , would enable prophylactic treatment strategies , such as vaccination , to be more appropriately implemented for control purposes . improved characterisation of the serovars could also aid in the identification of novel multiserovar drug and vaccine targets .
the aim of the present study was to characterise the proteome of l. interrogans serovar canicola and to compare this against the published proteomes of serovars copenhageni and pomona to identify proteins common to each and determine functionally important differences .
in addition characterisation of the serovar canicola proteome would provide a valuable resource for future research into the treatment and prevention of leptospirosis .
analysis of serovar canicola using 2d - lc / ms identified 2961 unique leptospira accession numbers across the three protein databases used ; 1653 of these had unique protein identifications which represents the detected proteome ( table 1 , appendix 1 in the supplementary material available online at http://dx.doi.org/10.1155/2014/572901 ) for the serovar ( peptide identifications are given in appendix 2 in the supplementary material ) .
this represents a substantial improvement in coverage over the serovar copenhageni and pomona proteomes previously determined by eshghi et al . and vieira et al .
whilst the studies performed by malmstrm et al . , cao et al . , and zhong at al .
all identified a larger number of proteins ( table 1 ) it is important to note that all of these studies benefited from a serovar specific protein database ; in addition the studies by malmstrm et al . and
cao et al . did not report the use of biological replicates . in the absence of a canicola specific genome sequence for data
interrogation the genome for serovar copenhageni was used in the first instance as a proxy , as previously reported , resulting in the identification of 1015 leptospira proteins .
further data interrogation using protein databases derived from two serovar lai genome sequences enabled an additional 638 proteins to be identified .
a comparison of the peptides identified in serovar canicola using the three different databases ( figure 1 ) demonstrated considerable variation between genomes , particularly for serovar lai which only had 1777 peptides conserved between the two genomes ( figure 1 ) .
this clearly demonstrates the inter- and intraheterogeneity of different serovars of l. interrogans at the peptide level and the need for future leptospira proteomic studies to search their data against multiple genomes where serovar / strain specific databases are unavailable .
proteins identified in serovars copenhageni and pomona were selected for further comparison against serovar canicola as their proteomes are freely accessible online .
the cellular contents of the proteins identified in the different studies were determined and compared ( figure 2 ) and analysis of the different functional groups of proteins identified in the three studies ( figure 3 ) was also performed to establish if there were any biological differences between serovars .
additional investigation , taking into account differences in the extraction and/or processing methodologies used in the different studies , is required to validate these observations ; however this does demonstrate the value of cross serovar analysis as an investigative tool .
a conserved proteome for the three serovars was subsequently determined ( appendix 3 in the supplementary material ) ; 60 proteins were revealed to be conserved ( appendices 35 in the supplementary material ) , sixteen of which have been previously reported in the literature as immunogenic ( table 2 ) through immune studies in the hamster and mice models and immunoblotting with serum from infected humans and mice .
further work is required to determine if any of the identified conserved proteins could be used as viable targets for therapeutic drugs , antimicrobials , and/or vaccines ; however this does suggest that proteomic comparison of serovars could also be used as an effective screening tool ; further refinement of the conserved proteome presented herein is suggested as the proteomes of additional serovars are published . in conclusion
this study provides the first reported proteome for l. interrogans serovar canicola , which is of particular importance due to its high frequency of infection in dogs .
the identified protein / peptide lists available in the appendices in the supplementary material also provide a valuable resource for future research into both serovar canicola and leptospira in general .
starter cultures of l. interrogans serovar canicola ( strain hond utrecht iv ; from ahvla , uk ) were prepared by inoculation of 20 ml emjh ( becton dickinson , usa ) media with 1 ml pure culture ( passage number 1 ) and incubated for 7 days at 30c with orbital agitation at 50 rpm .
larger working cultures ( n = 3 ) for proteome extraction were initiated by inoculation of 400 ml emjh media with 10 ml of starter culture and incubated at 30c ( 50 rpm ) .
bacteria were harvested during the logarithmic growth phase ( ~510 cells / ml ) by cooling the cultures on ice for 30 minutes and collection of cells by centrifugation at 4000 g for 20 minutes at 4c .
the number of bacterial cells was assessed by dark field microscopy using a thoma counting chamber ( 0.1 mm depth , 1/400 m ) .
the bacterial cells were washed by suspension in 100 ml chilled phosphate buffered saline ( pbs ; 200 mm , ph 7.2 ) and pelleted ( 4000 g ; 20 min , 4c ) .
bacterial cell pellets were suspended in pbs ( 10 ml ) containing pmsf ( 100 m ) and lysed by 6-second pulses of probe sonication ( amplitude 60 ) using a vibra - cell ultrasonic processor ( sonics and materials , usa ) for 3 minutes on ice .
a low speed cytosolic extract was produced from the supernatant by centrifugation at 32000 g for 30 minutes .
the pellet was retained and the supernatant ( cytosol extract ) was then desalted by dilution with ammonium bicarbonate ( 2.5 mm ; ph 8.0 ) , concentrated to 0.5 ml by centrifugation in 5 kda molecular weight cut - off concentrators ( sartorius stedim , france ) , and stored at 20c .
the retained pellet was then washed by suspension in chilled phosphate buffered saline ( pbs ; 200 mm , ph 7.2 ) and collected by centrifugation ( 32000 g ) .
the washed pellet was redissolved in 3 ml lysis buffer ( urea 5 m , thiourea 2 m , dtt 100 mm , chaps 2% , 3-(decyldimethylammonio)propanesulfonate inner salt 2% , tris base 0.48% ) and centrifuged at 32000 g for 30 minutes .
the protein extract was precipitated in a 4-fold excess of ice cold acetone and incubated at 20c for 48 hours prior to centrifugation ( 3000 g for 30 minutes ) .
the resulting pellet ( precipitated extract ) was desalted and concentrated as before using ammonium bicarbonate and vivaspin centrifugal filters , respectively .
estimation of protein concentration for both extracts was then determined using the bradford method ( sigma - aldrich , uk ) , with bovine serum albumin as the calibration standard ( 0.051.0 mg / ml ) .
three replicates of each bacterial extract , normalised by dilution in 2.5 mm ammonium bicarbonate ( ph 8.0 ) to 100 g of protein , were heat denatured at 95c for 5 minutes and then digested overnight with 2 g sequencing grade trypsin ( promega ) ; digestion was terminated by the addition of 1 l of 25.2 m formic acid ( fluka ) .
tryptic peptides ( 50 g ) were fractionated on a biobasic scx hplc ( 2.1 100 mm ) column ( thermo scientific , uk ) using a hewlett - packard 1100 hplc system , as previously described , at a flow rate of 0.25 ml / min .
mobile phases used were 75 : 25 2.5 mm ammonium acetate : acetonitrile ph 4.5 ( a ) and 75 : 25 250 mm ammonium acetate : acetonitrile ph 4.5 ( b ) with a binary gradient ( t = 0 min , a 100% ; t = 5 min , a 100% ; t = 18 min , 65% a ; t = 20 min , b 100% ; t = 22 min , a 100% ; t = 32 min , a 100% ) .
eluted peptides were monitored at 280 nm and 15 fractions ( 1 ml ) were collected between 8 and 23 min .
the scx fractions were taken to dryness at 60c under vacuum using an eppendorf 5301 centrifugal concentrator ( eppendorf , uk ) . dried scx fractions
were resuspended in 0.1% v / v formic acid ( 20 l ) and analyzed on an agilent 6520 quadrupole time - of - flight ( q - tof ) mass spectrometer ( agilent technologies , uk ) with an hplc chip cube source .
the chip consisted of a 40 nl enrichment column ( zorbax 300 sb- c18 ; 5 m ) and a 75 m 150 mm analytical column ( zorbax 300 sb- c18 ; 5 m ) driven by the agilent technologies 1200 series nano / capillary hplc system .
both systems were controlled by masshunter workstation data acquisition for q - tof ( version b.02.00 , patches 1 , 2 ; agilent technologies ) .
tryptic peptides ( 1 l injection volume ) were loaded onto the enrichment column of the chip and washed with eight column volumes of 0.1% v / v trifluoroacetic acid ( tfa ) .
tryptic peptides were separated on the analytical column and eluted directly into the mass spectrometer .
mobile phases used were 0.1% v / v tfa ( a ) and 90 : 10 acetonitrile : 0.1% v / v tfa ( b ) with a binary gradient ( t = 0 min , a 95% ; t = 5 min , a 95% ; t = 40 min , a 60% ; t = 41 min , a 20% ; t = 45 min , a 20% ; t = 47 min , a 95% ) at a flow rate of 0.6 l / min .
the mass spectrometer was run in positive ion mode , and ms survey scans were run over a range of m / z 250 to 3000 and at five spectra per second .
precursor ions were selected for auto ms / ms at an absolute threshold of 2000 and a relative threshold of 0.01 , with a maximum of 5 precursors per cycle , and active exclusion set at 1 spectra and released after 3 minutes .
precursor charge state selection and preference were set to 2 + and then 3 + .
the search engine spectrum mill ( agilent , uk ) was used to extract ms / ms data from masshunter acquisition files and proteins were subsequently identified by comparison of tryptic peptide product ion mass spectra against those generated in silico from a protein database .
search parameters included selection of trypsin as the proteolytic enzyme with up to two missed cleavage sites and a variable modification for oxidation of methionine residues ; precursor and product mass tolerances were set to 20 and 50 ppm , respectively .
identified protein lists ( and associated information ) with a spectrum mill protein score higher than 11 were exported as tab separated files for bioinformatics analysis . to date , only three genome sequences for leptospira interrogans , corresponding to serovars copenhageni ( strain fiocruz l1 - 130 ) , lai ( strain ipav ) , and lai ( strain 56601 ) , have been determined and published in peer - reviewed journals . to identify l. interrogans proteins present in serovar canicola ,
three custom protein databases derived from these published genomes were used for database interrogation ; proteins identified had at least two distinct tryptic peptides and were present in all three technical replicates .
proteins identified in the precipitated and cytosol extracts using the three databases were reassembled into a single proteome ( appendix 1 in the supplementary material ) using access ( microsoft , usa ) and duplicate identifications were removed based on protein name ; duplicate peptide identifications were removed based on amino acid sequence ( appendix 2 in the supplementary material ) and a venn diagram ( figure 1 ) was generated using venny to compare peptide identifications between the three databases .
functional annotation of proteins present in serovars canicola , copenhageni , and pomona was determined using the protein information resource ( pir ; http://pir.georgetown.edu/ accessed on 12/12/12 ) and proteins conserved between the three serovars were determined using access ( appendix 3 in the supplementary material ) . | over 230 serovars of leptospira interrogans have been identified ; however few have been completely characterised .
the aim of this study was to characterise the proteome of serovar canicola and to compare this against the serovars of copenhageni and pomona .
2d - lc / ms analysis identified 1653 leptospira proteins in serovar canicola ; 60 of these proteins were common to copenhageni and pomona , 16 of which are known to be immunogenic .
this study provides the first reported proteome for serovar canicola and suggests that proteomic comparison of different serovars could be used as a tool for identification of novel target molecules for vaccine development . |
the modern transformation of radiology into an essential guiding hand of medical practice began with the invention of computed tomography imaging in the early 1970s and continues today with novel applications based on molecular methods and nanotechnology .
the topical agenda of the 7th biannual symposium of the international society for strategic studies in radiology ( isr ) , advancing radiology through informed leadership , was chosen by program committee chairman maximilian reiser to promote exploration and discussion of radiology s continuing transformation , its implications for the care of patients , and , more broadly , its impact on the health - care systems of the world .
major themes of the symposium included the increasing role of image - guided therapeutic interventions , the central role of quality and safety , and the emergence of molecular imaging and nanotechnology .
the isr brings together thought leaders from academia and industry from around the world to share ideas , points of view , and new knowledge .
the following summary reflects the contributions of these diverse voices and provides a unique window for looking at important trends that are shaping the future of radiology .
the technology for minimally invasive , image - guided interventions is advancing rapidly , aided by the convergence of innovations from numerous scientific and medical disciplines . as a result , a host of new options for the minimally invasive diagnosis and treatment of disease are broadening the horizons of interventional radiology ( ir ) . fusion of images from different radiological techniques is allowing more accurate and targeted intraoperative navigation .
for example , preoperative 3d ct angiography is being successfully co - registered with intraoperative 2d angiography to provide better depth perception and navigation during angiographic liver interventions , with motion correction for breathing .
thus , the use of ultrasound to identify suspicious nodules may be accompanied by the use of a gamma probe to determine whether the nodules display functional activity indicative of cancer . in patients suspected to have prostate cancer , targeted biopsies guided by the fusion of ultrasound with mri and mr
for example , the insertion of miniature smart electromagnetic sensors into interventional tools such as guide wires or needles allows their progress through the body to be followed on a gps - like tracking system . in this approach
, the magnetic space of the patient is co - registered with preoperative 3d imaging data , essentially creating a road map for the intervention .
not only does this lessen the need for intraoperative imaging ( which may involve exposure to ionizing radiation and/or contrast media ) , it also opens up more possibilities for bringing information from sophisticated preoperative imaging techniques such as pet or mri directly into the interventional process .
ct - integrated robots place needles more accurately and consistently than humans , and with the use of treatment planning software , they can identify and access the most direct routes to their targets .
although their cost - effectiveness has not yet been proven in large - scale studies , they work rapidly and also reduce interventional radiologists exposure to radiation .
further tailoring of interventions is becoming possible through the advent of smart drugs that are designed to complement interventional techniques .
one example is thermodox , which consists of thermosensitive liposomal capsules that contain the chemotherapeutic agent doxorubicin .
the capsules release the doxorubicin only under the high temperatures induced by thermal ablation . when the capsules are injected into the tumor vasculature at the time of radiofrequency ablation , the doxorubicin takes effect throughout the tumor , including at the edges , where radiofrequency ablation alone tends to be ineffective . because the doxorubicin is released only in the heated area , its toxic side effects are limited .
another concept consists of combining the application of thermosensitive liposomal capsules with regional hyperthermia induced by noninvasive , image - guided focused ultrasound . with advances in nanotechnology
for instance , targeting antibodies or ligands could be attached to drug - carrying capsules made with bound metal ( to allow imaging ) .
not only the ligands , but the agents inside the capsules could be varied to target specific disease characteristics . in a new paradigm of molecular ir ,
molecular imaging - guided interventions could be used to determine the molecular characteristics of a disease and to subsequently deliver the appropriate targeted therapy . emerging cellular therapies
preliminary research suggests that the insertion of autologous bone marrow cells after myocardial infarction can improve left ventricular function and myocardial viability .
various imaging techniques , including mri , pet , and spect , have been used to assess the functional effects of cell therapy , and methods for tracking and labeling cells with radionuclides and superparamagnetic agents are being developed .
although extensive clinical trials are still needed , cellular therapy could potentially become an important alternative to heart transplantation for the vast numbers of patients suffering from severe heart disease .
mr - guided focused ultrasound ( mrgfus ) is another novel interventional technique that could have applications in a multitude of patients . in this procedure ,
hundreds of ultrasound beams are directed at a focal point , where they cause intensive local heating and tissue destruction .
the entire procedure , which is performed on an outpatient basis , takes place inside the bore of the mri magnet .
mr imaging is used to guide the beam , avoiding critical structures such as nerves , scar tissue , surgical clips , and bowels , and mr thermal mapping is used to monitor the temperature rise ( through a phase shift ) and tissue destruction .
mrgfus is gaining acceptance as a non - invasive treatment for uterine fibroids . in a study conducted in the uk ,
80/100 patients treated with mrgfus for uterine fibroids had significantly less severe symptoms 6 months after treatment .
data suggest that mrgfus may have more long - lasting effects in the treatment of uterine fibroids than the more invasive alternative of myomectomy .
destruction of periosteal nerves has been suggested as a possible explanation for the analgesic effect , which can not be explained simply by the avid absorption of ultrasound waves by bone .
although the inability of ultrasound waves to pass beyond bones limits the areas that can be directly accessed by the technique , mrgfus is now being evaluated for the treatment of intracranial tumors . even though 90% of the energy is reflected back by the calvarium
, enough power remains to thermally ablate a glioblastoma multiforme or liquefy a clot in acute stroke .
moreover , results in the treatment of breast cancer as well as soft - tissue metastases using mrgfus have been reported .
radiologists have an essential role to play in the development and application of mrgfus , as it requires substantial skill in the use of imaging to guide the ultrasound beam .
however , despite a history of introducing innovative and widely applicable techniques , the field of ir has grown at a very slow rate , such that in 2002 there were only around 200 ir training positions in the united states ( as compared to around 2,300 in cardiology the year before ) . to some leaders in the field
repeatedly , techniques that have started out in ir have ended up being adopted by organ - based specialties , and the referrals to ir for these procedures have dropped off .
for example , by 2003 , cardiologists in the us had caught up with radiologists in the performance of peripheral vascular stent procedures , and now the majority of such procedures are performed by cardiologists . with their direct access to patients ,
their comparatively large numbers of personnel , and their greater financial resources and research activity , organ - based specialties have tremendous advantages over ir in the competition for patients . to sustain and enhance the relevance of ir , adjustments to the standard ir training
arguably , more of the training could be focused on ir procedures and equipment and less on diagnostic imaging , while still providing the core skills necessary to achieve board certification in radiology .
efforts should also be made to increase recruitment into ir training programs , perhaps by looking for candidates outside the field of radiology , in specialties that attract more physicians who seek patient contact .
the move in europe to a 3-year core training with 2 years devoted to sub - specialty training should help in this regard .
should it remain within radiology ? or should it be organized into partnerships with separate organ - based specialties ?
one advantage of remaining within radiology is the access this affords to advanced imaging equipment .
however , if ir is to stay within radiology , the differences between the work of interventional radiologists and that of diagnostic radiologists must be addressed . for example , since the former can not bill as many procedures as the latter , they should perhaps have a separate accounting system .
more hospital and departmental resources should be devoted to marketing and community outreach for ir .
in addition , regardless of which organizational approach is pursued , interventional radiologists should seek to obtain the status of true clinicians , with admitting privileges and the administrative support and infrastructure that will allow them to take more direct responsibility for patient care .
interdisciplinary collaboration and involvement in research are also essential to enhance the growth of ir . at present
, ir lags far behind organ - based specialties in the publication of original research .
many promising new interventional techniques ( including most of those described above ) have yet to be validated through extensive clinical trials .
more studies are needed to demonstrate their benefits to patient outcomes as well as to workflow . with the continual advancement of technology ,
there are also endless possibilities for creating new interventional approaches . to enhance their contributions to research
, interventional radiologists should build strong collaborative ties with physicians in other specialties as well as with the radiochemists , physicists , computer scientists , engineers , and basic scientists whose knowledge is essential for developing new minimally invasive techniques .
regardless of whether they continue to be applied under the rubric of ir , the skills of interventional radiologists are going to be increasingly in demand .
furthermore , the interventional radiologist who can deliver a comprehensive range of emergency procedures will continue to be held in high regard by professional colleagues .
rising health - care costs in the developed world have led to increased scrutiny of the quality of care being purchased .
four broad components of quality health care are now widely recognized : appropriateness of care ( as opposed to overuse , underuse , or misuse of procedures ) ; coordinated care that links providers and information ; safe , error - free care ; and patient - centered , timely care .
the methods for evaluating these aspects of quality , however , are still being developed and debated .
one common way of gauging quality has been to compare usage of medical procedures across geographic regions , institutions , and individual providers . for years , wide variations in usage
as recently as 2003 , mcglynn et al . found that on average , americans received only about half of recommended medical care ( as defined by a panel of physicians working on the study ) .
underuse of medical processes was a much greater problem than overuse , with 46.3% of study participants not receiving recommended care and 11.3% receiving superfluous and potentially harmful care . within radiology
a study of the health - care provided to employees of general electric suggested that approximately half ( $ 60 million - worth ) of the radiological tests ordered were unnecessary .
nevertheless , when used appropriately radiological services can make health care better , quicker , and cheaper , most often by diminishing diagnostic uncertainty and obviating the need for additional ( and more invasive ) procedures .
more studies are needed to demonstrate that radiology can improve outcomes and reduce costs at every level , from the clinician , to the department , the hospital , the insurer , the community , and the nation [ 28 , 29 ] .
refinements in the criteria for test usage and reporting can lead to considerable increases in cost - effectiveness .
for example , a study in the uk found that the incremental cost of using breast mri would be 28,284 per cancer detected if it were applied in all patients who underwent mammography , but only 11,731 if it were applied in place of mammography for patients with brca1 and 15,302 if it were applied in addition to mammography in patients with brca2 .
partly as a result of such findings , the use of mri in patients at high risk for breast cancer is now being funded by the national health service ( nhs ) .
another study found that by not reporting lesions smaller than 6 mm seen on ct colonography , radiologists could substantially reduce costs and complications while producing only a trivial decrease in cancer detection .
to help develop imaging recommendations , more studies are needed to determine whether imaging tests are likely to improve clinical decision - making and outcomes .
modeling can be used for this purpose . to yield results that are applicable to a broad spectrum of clinical settings , more
meta - analyses of small studies , as well as more large multi - center studies should be done .
for example , the web site of the american college of radiology imaging network provides access to standard enrollment form templates and sample protocols .
decisions about cost - effective radiological test usage may be complicated by concerns about exposure to ionizing radiation .
increasingly , patients are becoming aware of the risks of radiation exposure . in the late 1990s ,
the european community issued directive 97/43/euratom outlining the need for justification , optimization , and auditing of the use of ionizing radiation in health care . over the past 5 years
, the european commission issued european guidelines for multislice computed tomography ( an update of an earlier set of guidelines for the use of ct ) and launched the project safety and efficacy of computed tomography : a broad perspective .
the latter project brings together radiologists and physicists from leading european academic institutions to study ct justification and radiation dose optimization and measurement and to design practical tools for improving practice ( e.g. , clinical decision trees and optimized ct techniques ) . the project has resulted in published papers , conference presentations , and a report to the commission .
furthermore , as ct is now widely available , relatively affordable , and quick , guidelines for limiting its use are being ignored to meet the demand for imaging , and it appears that many , perhaps even most , ct examinations performed in europe are being requested in advance of patients needs .
increasing the availability of both ultrasound and mri should reduce reliance upon techniques involving x - rays , particularly for young patients . to address the problem of radiation exposure more effectively
, the government must continue to support research and not only pass , but also enforce laws through auditing .
in addition , researchers must work closely with industry to ensure that quality and safety measures are incorporated into technology development , and leaders in government , health care and industry must prioritize quality and safety above ( real or imagined ) productivity .
various approaches are being pursued for improving and not just assessing the quality and appropriateness of health care . for patients on medicare in the us ,
efficiency measures have been proposed for the use of certain radiological examinations , including mri of the lumbar spine and mammography .
recall rates after mammograms are being evaluated to determine whether mammograms are being performed in the appropriate patients .
ultimately , to bring about large - scale changes in practice , information on performance at all levels will need to be made routinely available a process that will require substantial changes in health information systems , including automated entry of essential data for clinical decision - making .
health - care accreditation systems are now in use in the us , finland , and australia . in 2006 , the royal college of radiologists ( rcr ) and the society and college of radiographers began to develop the radiology accreditation project ( rap ) to assess radiological services in the uk . at present , the rap is still in the pilot stage and is voluntary .
accreditation requires demonstration of appropriate protocols for monitoring and assuring the quality of service relative to published standards for safety , patient experience , clinical performance , and utilization of resources and workforce .
it also requires the development of a quality improvement plan with achievable goals . both self - assessment and assessment by independent auditors
the rcr is also working to establish a system for re - licensing and re - certification of radiologists in the uk , with the goal of identifying poorly performing ones .
it is known that the performance of approximately 2% of radiologists in the uk falls 2 standard deviations below the mean , yet only 0.51% of radiologists are referred for evaluation by the national clinical assessment service .
theoretical knowledge and , to some extent , practical skills can be assessed by examinations or more complex tests .
however , assessment of professionalism and behavior has generally relied on informal feedback , which is often considered unreliable and ignored . in a survey that asked rcr members and fellows to choose the best methods for identifying poorly performing radiologists , third place went to peer review of cases , and second place went jointly to attendance at discrepancy / error / complications meetings and on - line assessments linked with educational programs .
first place went to a less conventional approach : multiple - source feedback , consisting of a confidential questionnaire for peers and patients , ranking of behavior , skills and knowledge , and computerized comparison of the radiologist s scores with those of other radiologists and doctors , ideally both nationally and locally .
rather than the assignment of pass or fail marks , the proposed multi - source feedback approach requires further evaluation of any radiologists who receive consistently low scores .
although much emphasis is now being placed on increasing efficiency , it is important to keep the focus of attention on the patient .
for example , the business objective of an inpatient unit is to reduce the length of the average patient stay in the hospital ; for radiology , this means minimizing the turnaround time from study request to study completion , which both shortens the patient s stay and improves the patient s care .
the use of flow charts in work process analyses can help identify ways to reduce waste and the potential for error .
for example , net savings may result from hiring an extra full - time technician to keep an expensive piece of equipment ( e.g. , an mri machine ) in operation during examination preparation times and the primary technician s lunch hour and coffee breaks .
conversely , for equipment that is less expensive to purchase and operate , it may be more cost - effective to buy many units , so that they can readily be used whenever needed , even if they are not constantly in use .
improving productivity and care requires establishing the right balance between equipment and staff and providing the necessary training for staff to make optimal use of equipment . at present , the error rate in the us health - care industry far exceeds those in the airline , telecommunications , and computer industries .
however , physicians and staff with average skills but an exceptionally well - designed work process will outperform those with better skills but a less coordinated work process .
approaches used to encourage communication in the airline industry , such as anonymous reporting of errors and elimination of penalties for errors , have been applied in health - care organizations and have been found to increase the rate of error reporting , stimulate discussions to improve work processes , and ultimately decrease the incidence of errors .
multidisciplinary team meetings allow radiologists to make recommendations for the clinically relevant use of imaging and deliver clinically relevant interpretations
. information technology , such as decision support for order entry and computer - aided diagnosis algorithms , can also help reduce errors and improve quality .
furthermore , teleradiology is increasingly being used around the world to augment local radiological services [ 44 , 45 ] . in the us , the most common use of teleradiology has been to allow radiologists to interpret images from home , but approximately 50% of radiological practices are now using outside service providers for interpretations on nights and weekends . in parts of europe and asia ,
teleradiology is being used across borders either to serve areas with a shortage of radiologists or to allow secondary consultations with specialists , or both .
the use of indian teleradiology services in singapore has improved care by reducing patient wait times and allowing more rapid clinical decision - making ; it has also forced radiologists in singapore to work faster in order to prove their worth .
limited communication may be the most significant drawback of teleradiology , as direct access to complete clinical information , including prior imaging studies , is rarely available , and teleradiology reports are usually submitted by e - mail or fax , without direct contact between the radiologist and the referring physician .
auditing is needed to ensure that teleradiologists meet the same certification and training requirements as local radiologists and that adequate clinical and technical standards are being maintained .
although a study comparing interpretations made by nhs radiologists with those made by teleradiologists at an independent service provider found few discrepancies , most of the cases examined were of low complexity .
the rcr , the american college of radiology , and the european society of radiology ( in conjunction with the european union of medical specialists ) have all issued fairly similar guidelines for quality assurance in teleradiology .
the potential of molecular imaging to revolutionize health care is often spoken of in rhapsodic terms . yet the practice of molecular imaging ( mi ) within radiology continues to be confined to a relatively small number of institutions and settings .
though mi already has clear applications in neurodegenerative conditions , cardiovascular disease , inflammation , and above all , cancer , a number of obstacles are impeding progress toward its broad clinical implementation some of them avoidable , others less so .
it is hoped that system characterization by imaging probes will ultimately allow molecular knowledge developed in the laboratory to be translated to clinical disease management . in combination with in - vitro molecular markers , mi (
performed mainly with multimodality techniques , such as pet / ct and pet / mr ) should facilitate earlier , even preclinical disease detection and characterization , prediction of prognosis , targeted treatment , and precise treatment follow - up , allowing personalized medicine that is tailored closely to the individual patient . however , both physical and technical factors make achieving this vision a highly complex and challenging endeavor .
the body is equipped with many barriers to molecular transport such as nuclear , cellular , and vessel walls , and the blood brain barrier .
the development of probes suitable for use in humans is limited by pharmacokinetics , biocompatibility , and toxicity concerns , and imaging speed and resolution .
contrast agents and radiopharmaceuticals must have sufficient half lives and must aggregate in sufficient concentrations to allow effective imaging once they have reached their target destinations . in addition , for any one disease , a limited number of overexpressed molecular markers will exist for targeting .
although mi with pet has been used successfully to explore how new drugs interact with targeted systems and to narrow the feasible dose ranges , pet imaging results can also be misleading .
for example , during its development , the anti - psychotic drug aripiprazole had no clinical effectiveness at the feasible dose range identified by pet , but in practice , the drug was found to be effective and safe at substantially higher doses . while mi can show on - target biological activity and provide essential information about the biodistribution of drugs , both more knowledge and more probes are needed to increase the reliability of mi for assessing drug effects . in certain instances , it may soon be possible for mi to play a role in disease stratification , patient selection for therapeutic agents , and dose selection , but mi is unlikely to replace clinical endpoints in drug development for a long time to come .
the advent of particle replication in non - wetting templates ( print ) technology has made it possible to mold nanoparticles small enough to cross the blood - brain barrier .
not only the size , but also the ability of nanoparticles to deform can be tailored to their purpose , increasing or limiting their uptake .
in addition , nanoparticles can be filled with cargoes ( e.g. , antibodies ) and can have entities ( e.g. , targeting ligands ) attached to their surfaces .
applications for which nanoparticle - based contrast agents are expected to be introduced into clinical practice within the next 10 years include imaging of metastatic lymph nodes , vulnerable atherosclerotic plaque imaging , macrophage imaging for inflammatory and degenerative diseases ( e.g. , multiple sclerosis , polyarthritis and osteomyelitis ) , and imaging of amyloid plaques in alzheimer s disease .
many more probes might now be on the horizon were it not for the vast amounts of time and money required to overcome regulatory hurdles . in the us , this problem has been exacerbated by misconceptions about regulatory requirements .
many applications for pharmacology / toxicology studies have been submitted with much more background data than necessary . in 2006 ,
the fda issued guidelines for exploratory investigational new drug ( ind ) studies ( e.g. , screening studies or microdose studies ) that are conducted early in phase 1 of the trial process , involve very limited human exposure for a short time period ( e.g. , 7 days ) , and have no diagnostic intent .
the guidelines explain that because exploratory ind studies present fewer potential risks than do traditional phase 1 studies that look for dose - limiting toxicities , they can be initiated with less , or different , preclinical support than is required for traditional ind studies .
exploratory ind studies allow a large number of agents to be tested rapidly in order to distinguish the promising from the not - so - promising , decreasing the likelihood of failure in later clinical trials .
while exploratory ind studies are extremely useful , further simplification of regulatory processes is necessary , as is the creation of a viable business model for probe development .
the development of mi probes that deliver drugs could allow much more targeted treatments of disease with less morbidity .
however , trials of such probes are especially complex and doubly risky for the sponsors , since either the imaging probe or the drug may fail .
collaboration between academia and industry in probe development has been hampered by concerns about intellectual property rights .
furthermore , lack of reimbursement discourages experimental use of molecular imaging in hospital settings , particularly since the required multimodality imaging techniques are expensive . despite these obstacles ,
collaboration between industry and academia is possible in mi research and probably essential for academic institutions . in a recent survey of academic radiology departments with mi programs in the us ,
another barrier to progress in the clinical implementation of mi is the need for expertise from multiple disciplines .
radiologists tend to have little understanding of molecular biology , and few have any familiarity with molecular imaging , since it is not included in standard clinical training . to encourage more radiologists ( and other physicians ) to become involved in the field , mi rotations should be created , and more mi fellowships should be offered . in the survey referenced above , respondents identified staff training and recruitment as the most essential elements for success . in light of the extensive training in both basic science and multimodality imaging required for the field ,
the creation of a new specialty of mi may be warranted , with the possibility of dual boarding in diagnostic radiology and mi , or nuclear medicine and mi . because mi involves not only multiple disciplines but multiple kinds of technology , its success will require major investments in human resources and infrastructure .
it will also require significant changes in organizational structures and the setting aside of turf battles .
conceivably , molecular biology , pathology , and imaging could be combined under one umbrella , perhaps that of biomedical imaging or imaging science . alternatively ( or concomitantly ) , the typical department of diagnostic radiology could be replaced by a department of diagnostics , combining pathology with radiology and mi , and using pathological analysis of genes and proteins to identify targets and create agents for mi in individual patients .
regardless of the specific restructuring plan chosen , broad clinical implementation of mi will depend on collaboration , co - training , and co - ownership .
regulatory requirements pose daunting barriers to the introduction of radiological innovations . for example , a pharmaceutical company is likely to spend over $ 300 million to bring a new contrast agent to market , in a process that typically takes about 9 years . and that is only the beginning . for each new indication , about $ 15 million more in funds
is required and around 5 more years , although most radiologists ignore the package insert and engage in off label use . while the process is somewhat less onerous in europe than in the us , regulatory hurdles appear to be increasing around the world .
the need to meet different regulatory requirements in different areas of the world adds to the complexity and costs of the process .
currently , regulations differ in the eu and the us , china and japan , with the regulatory policies of the latter two countries being closer to those of the us . in both the eu and the us ,
regulators look for accuracy ( e.g. , as measured by sensitivity and specificity ) , reliability , clinical value , and a favorable risk / benefit ratio .
however , far more contrast agents have been approved in europe than in the us to date .
this may be partly because us regulators seem to place a greater emphasis on the demonstration of p - values showing statistically significant increases in value over existing technology or agents , whereas eu regulators are more content to see any demonstration of utility , even if it is only for a secondary aim .
furthermore , in the us , the requirements are often not aligned with the intended use of the agent or device .
for example , even if the manufacturer s goal for a contrast agent is to increase tumor visualization , the fda may demand that the manufacturer also demonstrate an improvement in tumor diagnosis .
such a demand may prevent a useful agent from coming to market , or may require it to be tested ( and approved ) for a narrower cohort and indication .
thus , delays in the approval process for an agent can make the agent or the application tested obsolete by the time it becomes available .
moreover , partly because of the fast pace of technological change , standardization of imaging protocols in multi - center trials is difficult , as is comparison of the results of multiple single - center studies . in a phenomenon sometimes referred to as regulatory creep , the fda has repeatedly come back to manufacturers and pharmaceutical companies with requests for more data , more details , and stricter adherence to protocols . to prevent this
, the fda should be required to make binding agreements about what is required at the beginning of the regulatory process .
recently , the fda began to call for clinical trials to assess the use of a contrast agent on a new imaging platform , even when the contrast agent has already been approved .
this shortens the effective lifetime of the new device , reducing the incentive for the manufacturer to invest in the trial process . in japan ,
the average approval time for a new medical device in japan in 2004 was 1,083 days , compared to 356 in the us .
the number of new device applications submitted by us companies for review by japanese regulators fell from 132 in 2003 to only 8 in 2005a decrease of 94% .
representatives of the us medical technology industry cited burdensome applications and an unpredictable approval process as reasons for the decline . in the us
, it appears that increasing delays in the approval process are partially due to a lack of trained regulatory personnel , as well as regulators tendency to become concerned by negative anecdotal studies . in japan ,
where the approval process is even more complex , the number of experienced reviewers is even smaller , and there is a large backlog of applications .
it may seem curious that regulations should be multiplying even during times of reviewer staffing shortages .
some speculate that the changes may be part of a deliberate effort on the part of governments to reign in health - care spending by reducing the approval of new medical devices and drugs .
however , such a practice may in fact lead to greater social and economic costs overall .
increasing the duration and cost of the regulatory process is only likely to increase the cost of a medical device or agent once it comes to market .
furthermore , improvements in technology ultimately lower the cost of quality health care . for example , since ct was first introduced , the number of ct slices per second has increased from 1 in 1995 to 387 in 2006 ; meanwhile , the cost per slice has gone down , so that for the same overall price , much more information is acquired .
while it is easy to add up medical expenses , it is less easy to calculate the costs ( not to mention the ethical drawbacks ) of not delivering efficient , high - quality medical care . to speed up the introduction of innovations into clinical practice
members of academia and industry should encourage their governments to adopt the recommendations of the global harmonization task force , a partnership between regulatory authorities and regulated industry representatives from the european union , the us , canada , australia , and japan .
the development of new medical products could be streamlined through increased collaboration between industry and academia .
for example , the pattern in technology development has been to design a piece of equipment and then search for ways to apply it clinically a rather inefficient process .
more communication between members of academia and industry could allow technology to be developed in response to specific clinical needs .
fellowships enabling representatives of academia to train with industry ( or vice versa ) could lead to greater mutual understanding of priorities and could help improve multicenter clinical trials say , by facilitating standardization of technology and of institutional imaging protocols .
efficiency in product development could also be improved by considering the whole imaging system , rather than working on different parts of it in isolation .
modern imaging requires a series of steps , including data acquisition , data reconstruction , and processing , data analysis and output , and data interpretation .
different disciplines are involved in the design of the equipment used for the separate steps , including engineering , physics , and computer science .
greater communication among all disciplines involved is more likely to result in advances that improve the effectiveness of the overall imaging system .
trial design and conduct could also be improved with more collaboration among industry , academia , and government agencies
e.g . , through organizations such as the american college of radiology imaging network ( acrin ) .
curricula could be redesigned to mandate training in basic and clinical research all along the educational pathway , starting with medical school .
in addition , industry and academia could work together to train radiologists in the use of new imaging technology and applications even before they receive regulatory approval .
this could not only improve the performance of new devices or techniques in clinical trials , but also could lead to earlier , broader acceptance of the techniques and faster progress toward reimbursement .
regulatory requirements pose daunting barriers to the introduction of radiological innovations . for example , a pharmaceutical company is likely to spend over $ 300 million to bring a new contrast agent to market , in a process that typically takes about 9 years . and that is only the beginning . for each new indication , about $ 15 million more in funds
is required and around 5 more years , although most radiologists ignore the package insert and engage in off label use . while the process is somewhat less onerous in europe than in the us , regulatory hurdles appear to be increasing around the world .
the need to meet different regulatory requirements in different areas of the world adds to the complexity and costs of the process .
currently , regulations differ in the eu and the us , china and japan , with the regulatory policies of the latter two countries being closer to those of the us . in both the eu and the us ,
regulators look for accuracy ( e.g. , as measured by sensitivity and specificity ) , reliability , clinical value , and a favorable risk / benefit ratio .
however , far more contrast agents have been approved in europe than in the us to date .
this may be partly because us regulators seem to place a greater emphasis on the demonstration of p - values showing statistically significant increases in value over existing technology or agents , whereas eu regulators are more content to see any demonstration of utility , even if it is only for a secondary aim .
furthermore , in the us , the requirements are often not aligned with the intended use of the agent or device .
for example , even if the manufacturer s goal for a contrast agent is to increase tumor visualization , the fda may demand that the manufacturer also demonstrate an improvement in tumor diagnosis .
such a demand may prevent a useful agent from coming to market , or may require it to be tested ( and approved ) for a narrower cohort and indication .
thus , delays in the approval process for an agent can make the agent or the application tested obsolete by the time it becomes available .
moreover , partly because of the fast pace of technological change , standardization of imaging protocols in multi - center trials is difficult , as is comparison of the results of multiple single - center studies . in a phenomenon sometimes referred to as regulatory creep , the fda has repeatedly come back to manufacturers and pharmaceutical companies with requests for more data , more details , and stricter adherence to protocols . to prevent this
, the fda should be required to make binding agreements about what is required at the beginning of the regulatory process .
recently , the fda began to call for clinical trials to assess the use of a contrast agent on a new imaging platform , even when the contrast agent has already been approved .
this shortens the effective lifetime of the new device , reducing the incentive for the manufacturer to invest in the trial process . in japan ,
the average approval time for a new medical device in japan in 2004 was 1,083 days , compared to 356 in the us .
the number of new device applications submitted by us companies for review by japanese regulators fell from 132 in 2003 to only 8 in 2005a decrease of 94% .
representatives of the us medical technology industry cited burdensome applications and an unpredictable approval process as reasons for the decline . in the us
, it appears that increasing delays in the approval process are partially due to a lack of trained regulatory personnel , as well as regulators tendency to become concerned by negative anecdotal studies . in japan ,
where the approval process is even more complex , the number of experienced reviewers is even smaller , and there is a large backlog of applications .
it may seem curious that regulations should be multiplying even during times of reviewer staffing shortages .
some speculate that the changes may be part of a deliberate effort on the part of governments to reign in health - care spending by reducing the approval of new medical devices and drugs .
however , such a practice may in fact lead to greater social and economic costs overall .
increasing the duration and cost of the regulatory process is only likely to increase the cost of a medical device or agent once it comes to market .
furthermore , improvements in technology ultimately lower the cost of quality health care . for example , since ct was first introduced , the number of ct slices per second has increased from 1 in 1995 to 387 in 2006 ; meanwhile , the cost per slice has gone down , so that for the same overall price , much more information is acquired .
while it is easy to add up medical expenses , it is less easy to calculate the costs ( not to mention the ethical drawbacks ) of not delivering efficient , high - quality medical care .
to speed up the introduction of innovations into clinical practice , regulatory processes should be harmonized globally .
members of academia and industry should encourage their governments to adopt the recommendations of the global harmonization task force , a partnership between regulatory authorities and regulated industry representatives from the european union , the us , canada , australia , and japan .
the development of new medical products could be streamlined through increased collaboration between industry and academia .
for example , the pattern in technology development has been to design a piece of equipment and then search for ways to apply it clinically a rather inefficient process .
more communication between members of academia and industry could allow technology to be developed in response to specific clinical needs .
fellowships enabling representatives of academia to train with industry ( or vice versa ) could lead to greater mutual understanding of priorities and could help improve multicenter clinical trials say , by facilitating standardization of technology and of institutional imaging protocols .
efficiency in product development could also be improved by considering the whole imaging system , rather than working on different parts of it in isolation .
modern imaging requires a series of steps , including data acquisition , data reconstruction , and processing , data analysis and output , and data interpretation .
different disciplines are involved in the design of the equipment used for the separate steps , including engineering , physics , and computer science .
greater communication among all disciplines involved is more likely to result in advances that improve the effectiveness of the overall imaging system .
trial design and conduct could also be improved with more collaboration among industry , academia , and government agencies
e.g . , through organizations such as the american college of radiology imaging network ( acrin ) .
curricula could be redesigned to mandate training in basic and clinical research all along the educational pathway , starting with medical school .
in addition , industry and academia could work together to train radiologists in the use of new imaging technology and applications even before they receive regulatory approval .
this could not only improve the performance of new devices or techniques in clinical trials , but also could lead to earlier , broader acceptance of the techniques and faster progress toward reimbursement . | the international society for strategic studies in radiology ( is3r ) brings together thought leaders from academia and industry from around the world to share ideas , points of view and new knowledge .
this article summarizes the main concepts presented at the 2007 is3r symposium , providing a window onto trends shaping the future of radiology .
topics addressed include new opportunities and challenges in the field of interventional radiology ; emerging techniques for evaluating and improving quality and safety in radiology ; and factors impeding progress in molecular imaging and nanotechnology and possible ways to overcome them .
regulatory hurdles to technical innovation and drug development are also discussed more broadly , along with proposals for addressing regulators concerns and streamlining the regulatory process . |
we present a case of disseminated cysticercosis with extensive central nervous system ( cns ) involvement and extracranial dissemination in a young woman , which presented as a case of affective mood disorder with the chronic tension type headache .
the extra - cranial dissemination involved atypical head and neck regions such as posterior pharyngeal wall , masseter , pterygoids , paravertebral neck muscles and tongue .
though cysticercosis is the most common helminthic infection of the , cns disseminated cysticercosis is rare .
a few cases of neurocysticercosis presenting with psychiatric complaints have been reported , but there have been no reported cases of disseminated neurocysticercosis presenting with depression .
a 21-year - old woman residing in new delhi presented to the department of medicine with a history of insidious onset , progressive headache on and off for the past 6 months .
the headache was bilateral , dull aching in nature occurring at any time of the day and had no special character or precipitating factors .
it was associated with fatigue , low mood , irritability and loss of appetite , multiple somatic pains and crying spells .
initially , the headache was relieved by over the counter analgesics , but it used to recur after a few days .
after 2 months of persistent symptoms , she had consulted a physician where she had been diagnosed to have tension type headache . a formal psychiatric evaluation done at that time revealed minor depressive episode .
when her symptoms did not abate she was started on amitriptyline 25 mg once daily for prophylaxis of chronic tension type headache .
there was no history of blurring of vision , diplopia , squint , pain , redness or watering of eyes .
her elder sister had a history of seizure disorder for which she had been taking anti - epileptic drugs for the past 2 years .
a contrast enhanced magnetic resonance imaging was done , which showed multiple cystic lesions with eccentric nodules in bilateral basal ganglia , cerebellum , brainstem , cerebral hemispheres ; a few of them indenting the lateral ventricle .
similar lesions were seen in the scalp , posterior pharyngeal wall , masseter , pterygoids , paravertebral neck muscles and tongue [ figure 1 ] .
there was a single lesion in left orbit abutting the superior rectus and a single lesion in the right orbit abutting the optic nerve [ figures 2 and 3 ] .
x - ray of the thigh showed multiple cigar shaped calcifications [ figure 4 ] . her complete blood count , liver function test , kidney function test were within the normal limits . based on the imaging findings a definite diagnosis of neurocysticercosis with extra - cranial dissemination was made .
she was started on albendazole with oral steroids and neuroimaging follow - up was planned .
after 2 months follow - up , her headache had decreased and she did not complain of any myalgia .
magnetic resonance imaging showing cystic lesions in masseter , pterygoids , tongue and cerebral hemispheres magnetic resonance imaging brain showing multiple hypodense lesions in bilateral brain parenchyma with scolices and surrounding edema .
single cystic lesion in left orbit abutting optic nerve magnetic resonance imaging brain with cystic lesion in right orbit compressing optic nerve and superior oblique muscle plain x - ray of thigh showing multiple cigar - shaped calcifications
consumption of measly pork containing cysticerci leads to intestinal teniasis , but does not directly cause cysticercosis . when cysticerci involve the cns it leads to neurocysticercosis .
cases of disseminated cysticercosis have been reported from india with involvement of subcutaneous tissues , skeletal muscles , heart , lungs , spleen , pancreas and liver .
cysticerci are uncommon in the head and neck region apart from the orbit but cases of cysticerci of tongue , masseter , mylohyoid , lower lip , soft palate and sternocleidomastoid have been reported previously .
neurocysticercosis can present with seizures , headache , focal neurological deficit , encephalitis , dementia .
neurocysticercosis presenting as extrapyramidal disease ( parkinsonism and focal dystonia ) , kluver - bucy syndrome , weber 's syndrome and cortical blindness have also been reported .
hamed and el - metaal reported a case of neurocysticercosis presenting with depressive manifestations together with disturbance of writing , mild deep sensory loss , limb - kinetic apraxia , lack of coordination and dystonia of the right upper limb .
disseminated cysticercosis presenting as a mood disorder and mimicking a primary headache disorder has not been reported before . in our patient
our patient was treated with albendazole and oral steroids according to the consensus guidelines published by garca et al .
traditionally , tension type headache has been believed to have a psychological basis . even though studies have proved the neurobiological basis of these headaches ,
the psychological connotations of this diagnosis remain in the minds of physicians and it is easy to leap to this diagnosis in a clinical background of low mood , crying spells and other psychiatric complaints .
routine use of imaging modalities may be justified to rule out neurocysticercosis in endemic areas before making a diagnosis of a primary headache disorder .
an early diagnosis of cysticercosis and cysticidal treatment can prevent considerable morbidity in this setting . | neurocysticercosis is a common parasitic infection in india presenting usually with seizues , headache , focal neurological deficits .
neurocysticercosis presenting as a psychiatric illness is rare .
disseminated cysticercosis with involvement of central nervous system and head and neck muscles is rare even in endemic areas .
we present a case of disseminated cysticercosis , which presented with chronic tension type headache and affective mood disorder .
treatment with cysticidal drugs led to complete remission of psychiatric complaints .
in endemic areas history suggestive of mood disorder should not be used as supportive evidence of a primary headache syndome like tension type headche without ruling out secondary causes .
making an early diagnosis can prevent morbidity . |
triemthylaminuria , a rare genetic disorder also known as fish odor syndrome is a disorder of amino acid metabolism , caused by the deficiency of enzyme flavin containing monooxygenase ( fmo ) .
it is an uncurable condition and is characterized by a foul putrid smell emanating from the body , which can be socially repulsive and personally demoralizing .
the presentation may not be direct to a physician , but indirectly as depressive symptoms to a psychiatrist .
one such case is described here where a young unmarried girl was brought to medical help by her mother in a suicidal state after prolonged suffering in ignorance .
psychiatric intervention mainly by empathetic , supportive , behavioral and cognitive psychotherapy helped her regain confidence and an acceptable level of functionality in socio - academic sphere .
this was a case report of a 20-year - old unmarried female patient who reported to psychiatry out - patient department accompanied by her mother .
the presenting complaints were irritable mood , not taking interest in household chores , not socializing with friends and colleagues and dropped out of college for last 6 months . during the course of the interview , a peculiar putrid smell filled the air and on direct questioning in the next interview the mother gave h / o rotten ( intolerable ) vegetable smell emanating from her body .
although the odor was present since adolescence it was more noticeable since the last 2 - 3 years .
she had increased odor during the menstrual periods and after games / physical exertion , more toward the evening .
in an attempt to avoid criticism and ostracization she had receded in her social interactions . over the last 6 months
she had become irritable , easily moved to tears and anger in the house , lost interest in studies and refused to participate in the household chores .
she stopped going to college and had got herself enrolled in a graduate correspondence course .
personal history revealed uneventful childhood with no h / o abuse / trauma or separation from parental figures .
she was good in studies and made a lot of friends , was a stable extrovert .
she had a special liking for fried dals like moongdaal and daaalmoth ( a fried readymade preparation of yellow and black and green lentils , flakes , groundnut and spices ) .
fruit and salad intake was minimal and fish was consumed in the house once or twice a week .
rotten egg like emanating from her husband and she gave horrid details of the difficult time she had with him after marriage due to this odor ( only i know how i have tolerated him .
he being a male could get away with it but she is a girl , who will tolerate her ) .
there was no past h / o mood abnormality or genetic loading of mental illness or suicide in the family .
mental state examination revealed features of depression of moderate intensity and embarrassment with social isolation and disturbed sleep off and on . there were passive suicidal ideas present though no active plans or attempts .
t3 , t4 , thyroid stimulating hormone , liver function test , urea creatinine , erythrocyte sedimentation rate within normal limits .
urine for the ratio of trimethylamine ( tma ) to trimethylamine oxide ( tmao ) was positive for trimethylaminurea .
she was managed as a case of trimethylaminuria ( tmau ) and adjustment disorder ( depressive reaction ) and managed comprehensively in consultation with the physician .
dietary , drugs and counseling - cognitive and psychoeducation as well as behavioral and family counseling . repeated counseling sessions were held with an aim towards psycho education about the illness and behavioral management to mitigate the effects of the illness the fact was driven home that this was a rare condition , which varied in severity temporally and across individuals and there have been individuals who have lived with the condition satisfactorily with slight modification in lifestyle ( including her own father ) .
behavioral modifications - daily twice a day bath with use of available adjuncts to avoid body odor such as soap meant for sweaty skin , use of antiperspirant powder and scrubs especially over sweaty areas in social situations , avoiding humid situations / weather , light clothing , use of perfumes and deodorants . restarting social interactions with core group of friends and relatives while continuing her distance education .
family was counseled to be supportive and not critical even in a lighter vein ( vis - a - vis siblings ) .
dietary modifications were made to avoid the frequent munching of daals / lentil preparation and eggs .
drugs were started in the initial phase to tide over the depressive phase- t sertraline 50 mg od .
individualization / personalization of critical social cues , avoidance of critical self - appraisal all the time , positive self - image , avoidance of catastrophic inference drawn from perceived ( and sometimes real ) neglect ( there is no place for me in the society , i am doomed ) and activity scheduling . a no suicide pact was entered into . over a period of 4 weeks , she had recovered significantly in that there was hardly noticeable odor in the room when she came for interview , she smiled , looked more in control , was dressed smartly with a liberal sprinkling of perfume , had started limited social interaction and appeared confident , talked / discussed freely about the illness and was planning to take up a course in web designing and a job ( home based web designing ) thereafter . at 6 monthly review
she was euthymic , confident and has given consent to her family to look for a suitable match for her .
tmau , also known as fish odor syndrome is a rare metabolic disorder with an autosomal recessive pattern of inheritance .
this is due to a defect in the normal production of the enzyme fmo 3 . as a result of which
, the body loses the ability to properly break down tma from precursor compounds in food digestion into tmao .
tma then builds up and is released in the person 's sweat , urine and breath , giving off a strong fishy odor or strong body odor .
the odor is not necessarily fishy and the type of odor can vary from time to time .
it adversely affect the livelihood of the people who have it , as well as their families .
people , especially children , with the condition may face rejection or a lack of understanding from peers .
some people with tmau have a strong odor all the time , but most have a moderate smell that varies in intensity over time . individuals with this condition
the condition seems to be more common in women than men , for unknown reasons .
symptoms can worsen just before and during menstrual periods , after taking oral contraceptives and around menopause .
measurement of urine for the ratio of tma to tmao is the standard screening test .
however , some people affected by the disorder live relatively normal lives by managing their symptoms and with counseling .
ways of reducing the fishy odor may include :
avoiding foods such as eggs , legumes , certain meats , fish and other foods that contain choline , carnitine , nitrogen and sulfurtaking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gutusing slightly acidic detergent with a ph between 5.5 and 6.5studies have described the use of dietary supplements , activated charcoal and copper chlorophyllin with unconfirmed and variable clinical response . avoiding foods such as eggs , legumes , certain meats , fish and other foods that contain choline , carnitine , nitrogen and sulfur taking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gut using slightly acidic detergent with a ph between 5.5 and 6.5 studies
have described the use of dietary supplements , activated charcoal and copper chlorophyllin with unconfirmed and variable clinical response .
measurement of urine for the ratio of tma to tmao is the standard screening test .
. however , some people affected by the disorder live relatively normal lives by managing their symptoms and with counseling . ways of reducing the fishy odor may include :
avoiding foods such as eggs , legumes , certain meats , fish and other foods that contain choline , carnitine , nitrogen and sulfurtaking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gutusing slightly acidic detergent with a ph between 5.5 and 6.5studies have described the use of dietary supplements , activated charcoal and copper chlorophyllin with unconfirmed and variable clinical response . avoiding foods such as eggs , legumes , certain meats , fish and other foods that contain choline , carnitine , nitrogen and sulfur taking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gut using slightly acidic detergent with a ph between 5.5 and 6.5 studies have described the use of dietary supplements , activated charcoal and copper chlorophyllin with unconfirmed and variable clinical response . | a young lady presents to the psychiatry out - patient department with depressive symptoms .
evaluation revealed long standing stressor in the form of a foul odor emanating from her body and over a period of time resulting in social withdrawal and depression with significant impairment of day - to - day functioning .
a diagnosis of trimethylaminurea ( fish odor syndrome ) and adjustment disorder was arrived at .
careful empathetic handling with psychoeducation , behavioral and cognitive counseling and a short course of antidepressants helped her improve significantly with return to almost normal functioning . |
the prevalence of intestinal parasitic infection is high in sub - saharan africa , where the majority of hiv / aids cases are from [ 2 , 3 ] .
diarrhea causing opportunistic parasites like cryptosporidium parvum and isospora belli is common among hiv positive persons with cd4 count less than 200 cells/l [ 4 , 5 ] .
antiretroviral treatment ( art ) increases the length and quality of life and productivity of patients by improving survival and decreasing the incidence of opportunistic infections in people with hiv through reduction of the viral load and increasing the level of cd4 cells . nevertheless , in ethiopia
, few studies have tried to investigate the extent of intestinal parasitic infections in relation to art experiences and cd4 count [ 4 , 5 ] . therefore , we investigated the prevalence of intestinal parasites among hiv positive persons who were naive and who were on art in hiwot fana specialized university hospital , eastern ethiopia .
the study was conducted in hiwot fana specialized university hospital , harar , ethiopia .
the hospital is found in harari national regional state which is one of the federal democratic republic of ethiopia regional states located 515 km from addis ababa . in harar
a comparative cross - sectional study was conducted among naive and on art hiv positive persons in hiwot fana specialized university hospital from march to april , 2011 .
the study population was all the hiv positive individuals who were on art and pre art care in the art unit of the hospital during the study period .
individuals who were on parasitic treatments during the data collection period were excluded . the prevalence of intestinal parasites among art - naive group hiv positive individuals was taken as 50% and to detect a difference of 15% between the two groups with the assumption of 95% confidence level ( cl ) , power of 80% ( 0.84 ) and ratio 2 : 1 of those on art and art - naive group .
double proportion formula was applied to calculate the sample size which was 274 on art and 137 art - naive group .
small pieces of labeled clean plastic sheets and wooden applicator sticks were distributed and the participants were instructed to bring sizable stool specimen of their own . with the provision of specimen ,
then , it was examined by direct wet mount method using normal saline ( 0.85% nacl solution ) at hiwot fana specialized university hospital laboratory in order to prevent the loss of motile stage of parasites .
the remaining sample was preserved with 10% formalin and transported to the laboratory of medical laboratory sciences department haramaya university . in the laboratory , it was examined by formol ether concentration technique and modified zeihl - neelsen method ( for detection of opportunistic parasites cryptosporidium species , cyclospora cayetanensis , and isospora belli ) .
the most recent cd4 t - cells counts of the participants were obtained from their art fellow - up record in the hospital .
data were entered into epideta version 3.1 and transported to spss version 16 software for analysis .
the prevalence of intestinal parasites was determined in relation to different variables pearson 's chi square test was used to assess statistical significance difference between proportions .
a statistical test result was reported as significant when its p value was less than 0.05 .
ethical clearance was obtained from haramaya university colleges of health and medical sciences institutional research and ethical review committee .
all the participants were explained about the purpose and their right to participate or not to participate in this study . those who gave their written consent participated in this study .
those participants who were found positive for intestinal parasitic infection were treated free of charge using the standard drugs by nurses in art unit .
a total of 259 on art and 112 art - naive group hiv positive clients participated in the study , and the response rate was 86.7% . the mean age of the participants was 33.6 ( sd 10.04 ) and many of the art - naive group ( 68.5% ) and on art ( 70% ) participants were female .
the majority of the study subjects were in the age group of 2534 , married , daily laborers , and urban dwellers ( table 1 ) .
the overall prevalence of intestinal parasites among the study participants was 33.7% ( 125/371 ) .
it was significantly higher in the art - naive group ( 45.5% ( 51/112 ) ) compared to those on art ( 28.6% ( 74/259 ) ) ( p = 0.002 ) .
some were infected with nonopportunistic ( 31.8% ) and very few with opportunistic ( 3.5% ) parasites .
eleven parasite species were detected : entamoeba histolytica / entamoeba dispar ( 13.4% on art - naive group and 13.5% on art group ( p > 0.05 ) ) and giardia lamblia ( 7.1% on art - naive group and 8.5% on art group ) were the common ones .
opportunistic parasites like crypotospriudum ( 7.1% ) and isospora belli ( 4.5% ) were found only in art - naive group group . some of the art - naive group ( 26.8% ) and few of the on art ( 17.4% ) subjects were diarrheic ( p < 0.05 ) ;
most of them were infected with g. lamblia ( p > 0.05 ) , crypotospriudum species , i. belli , and s. stercolaris .
the overall prevalence of intestinal parasites was significantly higher among diarrheic ( 53.3% ( 40/75 ) ) as compared to nondiarrheic ( 28.7% ( 85/296 ) ) study participants ( p < 0.05 ) ( table 2 ) .
about 31% ( 31/100 ) , 17.3% ( 34/196 ) , and 13.3% ( 10/75 ) of the study participants with cd4 count less than 200 cells/l , 200499 cells/l and greater than or equal to 500 cells/l , respectively , were diarrheic .
the prevalence of diarrhea is significant in participants with cd4 count less than 200 cells/l ( p = 0.005 ) . in the bivariate analysis , age , sex ,
occupation , residence , education , and marital status of the participants did not show significant association with prevalence of intestinal parasites .
participants with cd4 count less than 200 cells/l ( cor : 1.93 ; ci : 1.03 , 3.61 ) , diarrheic ( cor : 2.84 ; ci : 1.69 , 4.77 ) , and art - naive group ( cor : 2.09 ; ci : 1.32 , 3.31 ) had higher risk of intestinal parasites .
the participants with cd4 count < 200 cells/l were 2.07 times more likely to be infected with intestinal parasites than those with cd4 count 500 cells/l .
the diarrheic participants and the art - naive group ones were 2.30 and 2.60 times more likely to be infected with intestinal parasites ( table 3 ) .
intestinal parasitic infections are the major causes of morbidity and mortality in hiv positive patients [ 47 , 10 ] . in this study , about 33.7% of the participants were infected with intestinal parasites .
the result is almost similar to the ones reported from afar , ethiopia , cameroon , and saudi arabia , but lower than those from jimma , hawassa , bahir dar , dire dawa and afar of ethiopia , india , kenya , and jakarta .
the difference in the prevalence might be due to differences in geographical location , sensitivity of diagnostic techniques , study participants ' immunity status , environmental hygiene , socioeconomic status , access to safe water supply , or other .
several species of protozoa and other intestinal parasites have been associated with acute and chronic diarrhea and even weight loss in hiv / aids patients [ 19 , 20 ] . in this study , entamoeba histolytica / e .
but it is higher than a report in ethiopia ( 4.2% ) , saudi arabia ( 5.2% ) , and jakarta ( 0.3% ) . it is lower than the one in kenya ( 58.3% ) and ethiopia ( 23.8% ) .
however , it is higher than report of 1.1% in ethiopia , 0.6% in senegal , and 1.9% in jakarta .
it is also lower than report of 16.6% in kenya and 16% in ethiopia .
the prevalence of crypotospriudum species was 2.2% and this is lower than the findings from other studies which are found in the range of 4.9% to 15.8% [ 5 , 1215 , 17 ] . while isospora belli was found at 1.3% .
this is lower than other studies which are found in the range of 3.9% to 11.7% [ 5 , 1315 ] .
the lower prevalence of both parasites in this study might be due to that our study participants are in the art care who were taking art and/or treatment for opportunistic infection
. the other reason might be due to difference in immunity , diarrheic status , environmental and personal hygiene of the study participants .
other nonopportunistic intestinal helimiths were identified at the rate of ranging from 0.5% to 4.0% .
this is similar to study carried out in ethiopia , but it is slightly lower than another study in ethiopia and saudi arabia . the effect of strongyloides stercoralis in hiv infected patients , which is disseminated strongloidiasis , was reported in another study . in this study
, we tried to compare the prevalence of intestinal parasites with the diarrheic status , cd4 count , and art experience of hiv positive persons .
the prevalence of intestinal parasites was significantly higher among diarrheic as compared to nondiarrheic groups .
the most common diarrheal causing parasites were e. histolytica , gardia lamblia , crypotospriudum species , isospora belli , and strongyloides stercoralis . similarly , there are reports which showed that diarrhea can be caused by opportunistic and nonopportunistic parasites [ 5 , 15 , 22 ]
. the association between opportunistic parasitic infection and hiv is widely reported [ 4 , 15 , 23 ] . however , in this study , most of the parasites identified were nonopportunistic . the relationship between nonopportunistic parasite and hiv was not well established . even though the defense against them might be damaged by hiv
, the exposure to this parasites are likely to occur independent of hiv infection but heavier parasitic load might accumulate as well as experience of delayed clearance of parasite in individual with concurrent hiv induced immunosupperssion [ 23 , 24 ] .
the prevalence of intestinal parasites was highly significant among those study participants with cd4 count < 200 cells/l in this study .
the correlation of cd4 count with opportunistic parasites could not be assessed because of small number of individuals infected with crypotospriudum species and isospora belli .
however , the association of these two parasites with hiv positive persons , who have cd4 count < 200 cells/l , is reported in other studies [ 4 , 5 , 15 , 23 ] the prevalence of intestinal parasites was significantly higher when art - naive group compared to those on art study participants
. opportunistic parasites , which are crypotospriudum species and isospora belli , were found only in art - naive group group .
art increases the immunity status hiv positive persons and decreases the incidence of opportunistic infections .
the detection method for microsoporidia was not employed and sensitive diagnostic techniques for strongyloides stercoralis and enetrobius vermicularis were not used . therefore , the prevalence intestinal parasites in our study participant may have been underestimated .
hiv negative control groups were not included in this study which was the other limitation .
opportunistic and nonopportunistic parasites were identified with a different rate . the prevalence of intestinal parasites was higher among those hiv infected individuals with diarrhea , low cd4 count , and art - naive group groups .
those results posit the need for considering early detection and treatment of intestinal parasites in hiv infected individuals in order to reduce their morbidity .
this seeks great attention by those clinical service providers who are working in the art unit .
adherence counseling of art , health information dissemination on environmental , and personal hygiene should also be given to hiv / aids patients .
in addition further large scale study by using different diagnostic techniques , hiv negative control and assessing predisposing factors of intestinal parasites is recommended . | background .
intestinal parasitic infection affects the health and quality of life of people living with hiv .
this study was aimed to determine the prevalence of intestinal parasites among hiv positive individuals who are naive and who are on antiretroviral treatment ( art ) in hiwot fana specialized university hospital , eastern ethiopia .
methods .
a comparative cross - sectional study was conducted on 371 ( 112 art - naive group and 259 on art ) hiv positive individuals .
stool specimens were collected and examined by direct wet mount , formol ether concentration technique , and modified ziehl - neelsen methods .
results .
the overall prevalence of intestinal parasitic infections was 33.7% ; it was significantly higher among the study participants who were art - naive group ( 45.5% ) ( aor : 2.60(1.56,4.34 ) ) and diarrheic ( 53.3% ) ( aor : 2.30(1.34,3.96 ) ) and with cd4 count < 200 cells/l ( 46% ) ( aor : 2.07(1.06,4.04 ) ) .
the most commonly identified parasites were entamoeba histolytica / e .
dispar ( 13.5% ) , giardia lamblia ( 8.1% ) , strongyloides stercoralis ( 4.0% ) , and cryptosporidium species ( 2.2% ) . conclusion .
hiv positive individuals with diarrhea and low cd4 count and art naive groups were more infected with intestinal parasites than their counterparts .
early stool examination and treatment of intestinal parasites for hiv / aids patients is essential . |
diabetic macular edema ( dme ) is the leading cause of vision loss in patients with diabetes.1 several studies have reported raised levels of vascular endothelial growth factor ( vegf ) in the aqueous humor of eyes with dme when compared with healthy eyes.24 anti - vegf therapy with pegaptanib sodium , ranibizumab , bevacizumab , and aflibercept has been shown to have beneficial effects in terms of a reduction in edema and central retinal thickening as well as in terms of vision gain or stability.511 on february 27 , 2013 , the national institute of clinical excellence in the uk recommended the use of ranibizumab for dme but only in the subgroup of patients with central retinal thickness ( crt ) of > 400 m.12 this decision was based partly on the evidence from recent randomized clinical trials , which showed that eyes with crt > 400 m at baseline had more improvement in terms of visual acuity ( va ) and crt than those with crt of < 400 m.10,13 with regards to the bevacizumab therapy for dme , however , numerous studies have reported varying visual outcomes.8,1416 several studies have found that the pattern of edema classified on spectral domain optical coherence tomography ( sd - oct ) has a significant influence on treatment response and visual outcome.1518 however , only one study to date has shown a greater treatment response to bevacizumab in eyes with a higher baseline crt > 350 m.19 given that the lower cost of small aliquots of bevacizumab from a compounding pharmacy has made bevacizumab a popular choice for intravitreal anti - vegf therapy in many countries,20 we therefore wanted to investigate whether eyes with dme and crt > 400 m had better visual and anatomical outcomes when treated with bevacizumab in a real - world setting .
this type of evidence may not only support the rationale of applying a crt cut - off in treating dme with anti - vegf therapy , but it may also be useful to clinicians in health care settings where patients have to opt for either ranibizumab or bevacizumab for personal economic reasons . in this study , we report visual and anatomical outcomes of eyes with dme treated with intravitreal bevacizumab on a pro re nata basis at a single tertiary center , and we also compare visual outcomes at 1 year .
the setting for this study was an intravitreal bevacizumab treatment service in a tertiary referral unit , provided by four specialists ( pll , se , ps , bm ) for patients with dme .
patients were referred from clinics within the birmingham and midland eye centre and from surrounding hospitals by their local ophthalmologists .
only the patients with center involving diffuse cystoid dme , or those that were unlikely to benefit from laser , were accepted into the treatment program . within the treatment program , eyes with dme
were managed according to a standard treatment algorithm : 1 ) all patients had a baseline va test , clinical examination , and sd - oct scan ( topcon 3d oct 1000 ; topcon corporation , tokyo , japan ) ; 2 ) after written informed consent , patients received intravitreal bevacizumab ( 1.25 mg in 0.05 ml ) under standard aseptic conditions ( bevacizumab supplies were from moorfields eye hospital s compounding pharmacy ) ; 3 ) following the first baseline treatment , patients attended one to three monthly monitoring visits for va , biomicroscopy , and sd - oct scan ; 4 ) after the first injection , retreatment was performed for any persistent macular edema on sd - oct unless there had been no additional response observed after repeated dosing in previous visits ; and 5 ) eyes that had minimal or no response to intravitreal bevacizumab in terms of sd - oct appearance were considered by the treating physician at any monitoring visit for intravitreal triamcinolone if this had not been tried prior to bevacizumab , as other intravitreal agents such as ranibizumab , fluocinolone , and aflibercept were not available at the time of the study . from this treatment program ,
consecutive patients undergoing intravitreal bevacizumab therapy for dme in at least one eye were identified from the departmental database . to obtain an adequate sample size of patients with up to 1 year of follow - up , patients who had their first injection from march 1 , 2009january 25 , 2012 , were included .
april 2013 by means of retrospective chart review to obtain biographical , va , and other data on injections and follow - up visits .
the final visit was defined as the visit that was either at 12 months from the baseline or the closest visit beyond the 12-month time point .
patients who had been discharged earlier than 12 months back to their local ophthalmologists in the surrounding hospital were excluded .
data on the number of intravitreal injections and the va and the crt at baseline and at the final 1-year time point were extracted from the charts and the sd - oct database . in addition , baseline sd - oct scans were retrospectively regraded to determine the presence of epiretinal membrane and vitreomacular traction , which are features known to be associated with a poor response . to evaluate the differential treatment response of severe and less severe dme
, patients were divided into group 1 ( < 400 m ) and group 2 ( > 400 m ) .
comparisons were made of crt and va between the groups and also within the groups ( final versus baseline ) .
two sample , two - sided , unpaired student s t - tests were used to make comparisons between the two groups ; one - sided , paired student s t - tests were used to compare the change in crt and the va within each group .
data analysis was performed using the statistical package for social sciences software ( spss inc . ,
also , 20 eyes of 17 patients were excluded due to the following reasons : insufficient follow - up ( eight eyes , six patients ) ; lack of final sd - oct ( four eyes , four patients ) ; delay in 12-month review date by more than 2 months ( three eyes , two patients ) ; coexisting retinal vein occlusion ( two eyes , two patients ) ; and missing data on acuity or treatment dates ( three eyes , three patients ) .
all eyes were confirmed on retrospective sd - oct regrading to have a cystoid pattern of dme with cysts in either inner or outer retinal layers . of these , 81 eyes of 66 patients had crt < 400 m ( group 1 ) and 94 eyes of 76 patients had crt > 400 m ( group 2 ) .
the baseline characteristics of these two groups of eyes and their exposure to treatment over the 12-month period are shown in table 1 .
both groups had similar numbers of eyes with preexisting epiretinal membrane and/or vitreomacular traction visible on sd - oct at the baseline .
although very few patients required intravitreal triamcinolone during the study period , more patients in group 2 required it .
four patients in group 1 received intravitreal triamcinolone compared to eight in group 2 during the study period .
group 2 patients had significantly more injections than group 1 patients ( 4.0 versus 3.3 ; p=0.003 ) .
the amount of reduction in crt was significantly greater in group 2 when compared to group 1 ( p<0.0001 ) . in terms of va , both groups had comparable visual acuities at the baseline and gained by a mean of 0.12 logarithm of the minimum angle of resolution ( logmar ) units ( equivalent to six letters ) between baseline and month 12 .
the difference between groups 1 and 2 in terms of visual gain was not statistically significant ( p=0.99 ) . within each group , however , there was an improvement in the va from the baseline to the final of 0.12 logmar units .
the results from this study demonstrated the treatment response that could be achieved with intravitreal bevacizumab , as both groups of eyes showed a significant improvement in crt measurements , with the greatest anatomical response in the group with crt > 400 m .
this finding of a differential anatomical response depending on baseline crt is in keeping with one study using bevacizumab by soheilian et al and also in studies using ranibizumab.13,19,21 evidence for a differential response in terms of visual gain is less clear . in this study
, we could not demonstrate a significant difference in visual outcome between eyes with > 400 m or < 400 m of crt due to dme but admittedly the entry criteria of this study differed from the ranibizumab clinical trials in that the mean baseline va in our study was lower by about 0.2 logmar units ( ten letters ) .
both groups had a modest improvement of about six letters ( 1.2 logmar units ) .
to our knowledge , only one published study on bevacizumab in dme has performed subgroup analysis of visual outcome based on baseline crt.19 in that study , soheilian et al19 found that eyes with a baseline central macular thickness of < 250 m had significantly greater va improvement than eyes with > 350 m but their follow - up period was only up to 36 weeks .
it is also worthwhile to note that a reduction on foveal thickness has also been demonstrated in a study that used intravitreal pegaptanib.22 these results suggest that in terms of differential visual gain from treating dme with bevacizumab , the 350 m or 400 m baseline crt cut - off is not currently supported by the evidence from this study and from the published literature .
this is in contrast to the published data on ranibizumab in dme . in the restore study ,
for instance , eyes with a baseline crt of > 400 m gained approximately six letters while the eyes with a baseline crt of < 300 m gained only three letters at 12 months.10 in the diabetic retinopathy clinical research network protocol i study , eyes with a baseline crt of > 400 m had a mean gain of eleven letters while eyes with < 400 m had a mean gain of seven letters at 2 years.13 a possible reason for the discrepancy in differential visual outcome between our study and those from large clinical trials could be due to the chronicity of dme . in our study , all patients had cystoid pattern on regrading of sd - oct ; this would indicate a population with more chronic dme . in the diabetic retinopathy clinical research network protocol
i study , approximately 40% of all patients treated with ranibizumab did not have prior laser and , in the restore study , the mean duration of dme prior to study entry was < 2 years.10,13 indeed , the chronicity of dme and the presence of cystoid spaces on sd - oct were found by shimura et al to be poor prognostic factors for visual improvement when treated with intravitreal bevacizumab.18 in this study , both groups had a small or modest gain in va , despite achieving a considerable reduction in crt .
this may be explained by a poor correlation between the functional and the anatomical response , which has been described with bevacizumab and between triamcinolone and ranibizumab.13,21,23 the other explanation is the lack of correlation between crt and va , which is also well documented.2426 the lack of correlation between macular thickness and va suggests that an anatomical parameter , based on a finite threshold of macular thickness , is unlikely to be a good predictor of treatment response in terms of visual gain .
this would have the effect of making the treatment less cost - effective in patients with thicker crt .
the differential number of injections between subgroups in the restore and protocol i studies was not taken into account when the cost - effectiveness of each subgroup was considered in the national institute of clinical excellence appraisal of ranibizumab for dme.10,12,13 this may have led to an overestimation of the cost - effectiveness of treating the subgroup of patients with dme > 400 m .
visual acuities were not measured with a refraction protocol at regular visits as in a prospective clinical trial .
therefore , the overall efficacy of bevacizumab therapy could not be judged from our visual outcome data . however
, this is unlikely to have a great impact on the interpretation of the difference in treatment response between eyes with > 400 m or < 400 m of dme , as we performed sd - oct regrading to ensure that both groups were balanced in terms of consistency of crt measurements , presence of cystoid change , and confounding characteristics , such as epiretinal membrane .
we were able to balance the two groups in terms of influencing factors , such as epiretinal membrane presence , sex , and age , but we did not have the ability to collect accurate data to demonstrate the balance of other influential factors such as the duration of diabetes and blood pressure . as the patients in this study were all at the severe end of the spectrum , we feel it is unlikely that this omission should affect our ability to answer the specific study question on the issue of a 400 m threshold .
the absence of an effect of a 400 m threshold seen in this study does not necessarily invalidate the 400 m threshold seen in the ranibizumab studies , such as the restore trial .
the strength of this study lies in the consecutive nature of its fairly large series , which we feel reflects the unselected population that would present to any secondary care facility providing bevacizumab therapy for patients with dme .
therefore , our study results should be useful for practitioners who have to consider the use of bevacizumab in patients with crt of either > 400 m or < 400 m without applying other exclusion criteria , such as dme duration , blood pressure , glycemic control , or sd - oct pattern as would be the case when translating from prospective randomized trials designed to evaluate efficacy .
the issue of the unlicensed use of bevacizumab for the treatment of dme , when there is a licensed alternative ( ranibizumab ) , is still a controversial one .
a recent review27 of published outcomes on the use of these two agents in various studies for this indication did not reveal any significant differences in clinical effectiveness and adverse events , and we agree with the authors of this review that a head - to - head study would provide a much - needed evidence base for those clinicians who have to continue using bevacizumab for treatment of dme .
in conclusion , we were unable to demonstrate a difference in functional outcome between patients who were grouped according to an anatomical threshold of 400 m of crt at baseline .
our results do not support a preferential selection of those with dme and crt > 400 m at the baseline for intravitreal bevacizumab . on the contrary
, we found that patients with thicker crt required more injections rendering the treatment potentially less cost - effective .
as there are no published studies to show equivalence between bevacizumab and ranibizumab for dme , it is not possible to say if we can translate these findings in the use of ranibizumab in dme . | purposeto investigate whether eyes with diabetic macular edema ( dme ) and central retinal thickness ( crt ) > 400 m had better visual and anatomical outcomes compared to eyes with a crt < 400 m when treated with intravitreal bevacizumab in a real - world setting.patients and methodspatients undergoing intravitreal bevacizumab therapy for dme were identified from the departmental database of a tertiary referral unit .
following the initial injection , a retreatment was performed for any persistent macular edema , unless there had been no previous response to repeated doses .
recorded parameters included visual acuity , crt on optical coherence tomography ( spectral domain optical coherence tomography [ sd - oct ] ) , and sd - oct characteristics .
comparisons were made between data at baseline and 12 months after the first injection , and differences were tested for statistical significance using the student s t-test.resultsin all , 175 eyes of 142 patients were analyzed .
patients in group 2 ( crt > 400 m ) had significantly more injections than group 1 ( crt < 400 m ) ( 4.0 versus 3.3 ; p=0.003 ) .
both groups had similar numbers of eyes with preexisting epiretinal membrane and/or vitreomacular traction at baseline .
the reduction in crt was significantly greater in group 2 when compared to group 1 ( p<0.0001 ) . in terms of visual gain between baseline and month 12 ,
each gained significantly by a mean of 0.12 logarithm of the minimum angle of resolution units ( p=0.0001 ) , but there was no difference between groups 1 and 2 ( p=0.99).conclusionthese results do not support a 400 m baseline crt cut - off for treating dme with bevacizumab , in contrast to published data on ranibizumab .
our results also indicate that patients with a thicker crt require more bevacizumab injections , making treatment less cost - effective for these patients .
our results could be used by practitioners to support the use of bevacizumab in dme without applying a crt cut - off . |
herpes zoster is an acute , cutaneous viral infection caused by the reactivation of varicella - zoster virus ( vzv ) that is the cause of varicella ( 1 ) .
reactivation of varicella - zoster virus ( vzv ) that has remained dormant within dorsal root ganglia , often for decades after the patient s initial exposure to the virus in the form of varicella ( chickenpox ) , results in herpes zoster ( shingles ) ( 2 ) .
it is usually a self - limited dermatomal rash with pain ; but can be far more serious and lead to postherpetic neuralgia ( phn ) ( 3 ) . those with no previous exposure to vzv develop the clinical syndrome of varicella ;
zoster probably results most often from a failure of the immune system to contain latent vzv replication ( 4 , 5 ) .
whether other factors , such as radiation , physical trauma , certain medications , other infections , and stress can trigger zoster , is not fully clear ( 5 ) .
the incidence of zoster is inversely correlated with the host s immune response ( 4 , 5 , 6 ) . however , many patients with zoster have normal immunity .
zoster occurs when vzv antibody titer and cellular immunity drop to levels no effective in preventing viral invasion ( 6 , 7 ) .
when vzv infection resolves , many individuals continue to suffer pain - a condition known as postherpetic neuralgia ( phn ) ( 7 ) .
the clinical manifestations of herpes zoster can be divided into the 3 phases : a ) pre - eruptive phase ( preherpetic neuralgia ) which is characterized by sensory phenomena along 1 or more skin dermatomes , lasting 1 - 10 days ( average 48 hours ) , phenomena usually are noted as pain or , less commonly , itching or paresthesia .
pain may simulate headache , iritis , pleurisy , brachial neuritis , cardiac pain , appendicitis or other intra - abdominal disease , or sciatica that can result in incorrect tentative diagnoses .
other symptoms may be present such as malaise , myalgia , headache , photophobia , and , uncommonly fever ( 1 - 7 ) .
b ) acute eruptive phase is marked by patchy erythema , occasionally accompanied by indurations , in the dermatomal area , regional lymphadenopathy ; at this stage or subsequently , grouped herpetiform vesicles developing on the erythematous base , cutaneous findings typically appear unilaterally , stopping abruptly at the midline of the involved dermatome ; vesicles initially are clear but eventually cloud , rupture , crust , and involute .
scarring can occur if deeper epidermal and dermal layers have been compromised by excoriation or secondary infection .
pain may remain the same as in prodrome or may change in character and intensity ; patients describe it as burning , throbbing , or stabbing ; it may be severe , mild , constant , rare , or felt as another sensation such as itching . some patients experience pain without a vesicular eruption ( i.e. zoster sine herpete ) .
complete healing of lesions may require up to a month or more ( 1 - 7 ) .
c ) chronic phase ( phn ) is characterized by : persistent or recurring pain lasting 30 or more days after the acute infection ( 9 - 45% of cases ) .
the pain can be severe and incapacitating ; can persist for weeks , months , or years which is especially common in the elderly ( > 60 years ) .
phn is observed more frequently after cases of herpes zoster ophthalmicus and in upper - body dermatomal involvement .
less common postherpetic squeals include hyperesthesia or hypoesthesia or anesthesia ( 1 - 7 ) .
herpes zoster oftalmicus , herpes zoster of maxillary branch of cranial nerve ( cn ) v , herpes zoster of mandibular branch of cn v , herpes zoster oticus ( ramsay hunt syndrome ) , glossopharyngeal and vagal herpes zoster , herpes occipitocollaris ( vertebral nerves c2 and c3 involvement ) , herpes zoster encephalomyelitis , disseminated herpes zoster , unilateral herpes zoster involving multiple dermatomes , recurrent herpes zoster , herpes zoster involving urinary bladder , bronchi , pleural spaces , or gastrointestinal tract , herpes zoster with motor complications ( 1 - 7 )
. diagnosis of herpes zoster is based primarily on the history and physical findings - specifically , the characteristic location and appearance of the skin eruption in association with localized pain .
laboratory studies for vzv include the : direct fluorescent antibody ( dfa ) testing of vesicular fluid or a corneal lesion , polymerase chain reaction ( pcr ) testing of vesicular fluid , a corneal lesion , or blood , tzanck smear of vesicular fluid . in most patients , confirming the diagnosis via laboratory testing usually has no utility . in selected patients ,
the presentation of herpes zoster can be atypical and may require additional testing ( 8 - 10 ) .
varicella - zoster virus ( vzv ) can be cultured ; its growth rate is usually too slow to be useful to diagnosis ( 9 ) .
herpes zoster is seen approximately 7 times more frequently in patients with hiv infection so hiv test should be done ( 4 ) .
the goals of therapy for herpes zoster are : to shorten the clinical course , provide analgesia , prevent complications and decrease the incidence of phn ( 11 - 15 ) .
ideally , antiviral therapy should be initiated within 72 hours of symptom onset but should be considered regardless of the time of presentation ( 12 ) .
a 7 to 10-day course of acyclovir is appropriate ; longer courses may be needed in immunocompromised patients who sometimes need intravenous therapy ( 14 ) .
once phn has developed , various treatments are available : nonsteroidal anti - inflammatory drugs ( nsaids ) , neuroactive agents ( e.g. antidepressives- tcas ) , anticonvulsant agents ( e.g. gabapentin , pregabalin ) , narcotic and nonnarcotic analgesics systemic and topical ( 14 , 15 ) .
the clinical manifestations of herpes zoster can be divided into the 3 phases : a ) pre - eruptive phase ( preherpetic neuralgia ) which is characterized by sensory phenomena along 1 or more skin dermatomes , lasting 1 - 10 days ( average 48 hours ) , phenomena usually are noted as pain or , less commonly , itching or paresthesia .
pain may simulate headache , iritis , pleurisy , brachial neuritis , cardiac pain , appendicitis or other intra - abdominal disease , or sciatica that can result in incorrect tentative diagnoses .
other symptoms may be present such as malaise , myalgia , headache , photophobia , and , uncommonly fever ( 1 - 7 ) .
b ) acute eruptive phase is marked by patchy erythema , occasionally accompanied by indurations , in the dermatomal area , regional lymphadenopathy ; at this stage or subsequently , grouped herpetiform vesicles developing on the erythematous base , cutaneous findings typically appear unilaterally , stopping abruptly at the midline of the involved dermatome ; vesicles initially are clear but eventually cloud , rupture , crust , and involute .
scarring can occur if deeper epidermal and dermal layers have been compromised by excoriation or secondary infection .
pain may remain the same as in prodrome or may change in character and intensity ; patients describe it as burning , throbbing , or stabbing ; it may be severe , mild , constant , rare , or felt as another sensation such as itching . some patients experience pain without a vesicular eruption ( i.e. zoster sine herpete ) .
complete healing of lesions may require up to a month or more ( 1 - 7 ) .
c ) chronic phase ( phn ) is characterized by : persistent or recurring pain lasting 30 or more days after the acute infection ( 9 - 45% of cases ) .
. the pain can be severe and incapacitating ; can persist for weeks , months , or years which is especially common in the elderly ( > 60 years ) .
phn is observed more frequently after cases of herpes zoster ophthalmicus and in upper - body dermatomal involvement .
less common postherpetic squeals include hyperesthesia or hypoesthesia or anesthesia ( 1 - 7 ) .
herpes zoster oftalmicus , herpes zoster of maxillary branch of cranial nerve ( cn ) v , herpes zoster of mandibular branch of cn v , herpes zoster oticus ( ramsay hunt syndrome ) , glossopharyngeal and vagal herpes zoster , herpes occipitocollaris ( vertebral nerves c2 and c3 involvement ) , herpes zoster encephalomyelitis , disseminated herpes zoster , unilateral herpes zoster involving multiple dermatomes , recurrent herpes zoster , herpes zoster involving urinary bladder , bronchi , pleural spaces , or gastrointestinal tract , herpes zoster with motor complications ( 1 - 7 ) .
diagnosis of herpes zoster is based primarily on the history and physical findings - specifically , the characteristic location and appearance of the skin eruption in association with localized pain .
laboratory studies for vzv include the : direct fluorescent antibody ( dfa ) testing of vesicular fluid or a corneal lesion , polymerase chain reaction ( pcr ) testing of vesicular fluid , a corneal lesion , or blood , tzanck smear of vesicular fluid . in most patients , confirming the diagnosis via laboratory testing usually has no utility . in selected patients , the presentation of herpes zoster can be atypical and may require additional testing ( 8 - 10 ) .
varicella - zoster virus ( vzv ) can be cultured ; its growth rate is usually too slow to be useful to diagnosis ( 9 ) .
herpes zoster is seen approximately 7 times more frequently in patients with hiv infection so hiv test should be done ( 4 ) .
the goals of therapy for herpes zoster are : to shorten the clinical course , provide analgesia , prevent complications and decrease the incidence of phn ( 11 - 15 ) .
ideally , antiviral therapy should be initiated within 72 hours of symptom onset but should be considered regardless of the time of presentation ( 12 ) .
a 7 to 10-day course of acyclovir is appropriate ; longer courses may be needed in immunocompromised patients who sometimes need intravenous therapy ( 14 ) .
once phn has developed , various treatments are available : nonsteroidal anti - inflammatory drugs ( nsaids ) , neuroactive agents ( e.g. antidepressives- tcas ) , anticonvulsant agents ( e.g. gabapentin , pregabalin ) , narcotic and nonnarcotic analgesics systemic and topical ( 14 , 15 ) .
a middle - aged female clinical doctor with no previous data of serious ill conditions had got over the chicken pox in early childhood ( when she was five years old ) .
she had no feeling of any health disorder but these days in the beginning of november of 2015 year she had too much work in her workplace in the hospital : in a short time several nights on duty with big number of seriously ill patients . in her private life
she had a very big emotional stress some financial problems of buying new apartment with neglecting proper nutrition in that period .
around 10 of november she began to feel fatigue , anorexia , general weakness , irritability , mild depression , which she explained that she was overworked .
on the 12 of november when she went to sleep she felt the discomfort and mild pain beside the spine in the level of right scapula .
she had difficulties in falling asleep with a number of awakenings during the night with feeling of discomfort and mild pain in the right shoulder , upper arm and right elbow . in the morning 13th of november
she noticed the red skin indurated papules the size of a few millimeters to half a centimeter in diameter in the palmar side in the root of ring finger . during the day a few indurated papules appeared in the border between the palmary and dorsal side of the right hand in the area of innervations of the ulnar nerve . on the 14 of november a couple of the same indurations appeared in the palmary side of right hand in the root of forearm , and in the region of pinkie finger . in the next few days ( 4 to 5 days )
skin of the ulnary side of the palm of the right hand became erythematous and grouped herpetiform vesicles developed hour by hour , day after day and almost complete clinical picture was developed on the 17 of november .
the vesicles were cloudy , some of them with red border , some of them merged in blisters more than 2 centimeters in diameter . that day
she went to doctor dermatologist who characterized the appearance as hemorrhagic form of herpes zoster and therapy was prescribed : acyclovir tbl 5x 800 mg two days and 5x600 mg 4 days four days , broad spectrum antibiotic , vitamins b12 and b1 , b6 , analgesics and acyclovir cream locally several times on day .
the entire time patient felt fatigue , general weakness , discomfort and pain in most expressed in elbow and in ulnar side of forearm , ulnaro - carpal joint and in the palmary and dorsal side of the right hand all in projection of the branching of ulnar nerve .
it might be reduced by no steroidal anti - inflammatory drugs ( ibuprofen ) 3 to 4 tablets per day . during the first three days of therapy some new vesicles erupted .
about 10 days after first eruption some vesicles started converting into crusts with no new vesicle eruption .
after vesicular involution , there was slow resolution of the remaining erythematous plaques , but with visible squeals .
on the control examination ( 10 day after first examination ) the dermatologist characterized illness as gangrenous form of herpes zoster with recommendation to patient to examine her immune system and to use panthenol ointment for epithelialization and skin regeneration long time and eozine ( antiseptics ) locally for five to six days .
she has done blood testing ( esr - erythrocyte sedimentation rate , fbc whole blood count , liver and kidney laboratory tests , rheumatic tests , oraquick hiv test , urine examinations , chest x- ray , ultrasound examination of abdomen and pelvis .
from day to day she felt better and better but 30 days after the begging of illness she still have crusts in the places of vesicles , the largest one on the ulnar side of the palm of right hand with mild pain in involved area .
two months after first vesicular eruption there are sequels in the form of the pink stains in the places of previous vesicles with mild hyperesthesia in involved area and very mild occasional pain in there especially in the evening . the appearance of skin manifestations in first seven days is presented in the figures 1 , 2 , 3 .
c ) vesicles on the region of ulnaro - carpal joint of right hand vesicles on the ulnar side of right forearm .
c ) scars on the ulnar side of right forearm a ) scars on the ulnar side of right hand .
c ) skin laesions of right hand palm after 45 days of first eruption of herpetic vesicles
herpes zoster is an acute , cutaneous viral infection caused by the reactivation of varicella - zoster virus ( vzv ) that is the cause of varicella .
it often leads to postherpetic neuralgia ( phn ) when many individuals especially older ( > 60 years ) continue to suffer a serious pain .
zoster probably results from a failure of the immune system to contain latent vzv replication .
whether other factors can trigger zoster has not been determined with certainty although many patients with zoster apparently have normal immunity . in this study
we present a case of female doctor who prior this illness had had no problems with her immune system but it is obviously that in this period it came to intensive decline of the immune system that resulted in this severe form of the disease .
only explanation for this decline of her immune system is her overwork over strain , great emotional stress she was exposed to with sleep disorders because of stress and eating disorders from the same reason .
herpes zoster is acute neurological disease which can include different nerves with appropriate skin manifestations in their areas of innervations .
the most common involved nerves are cranial nerves ( first of all v ( fifth ) , e.g. n.trigeminus with its branches first of all ophtalmucus ) , intercostal nerves . in this report
we show the uncommon localization of herpes zoster ulnar side of right hand and forearm in the anatomic region of innervations corresponding to ulnar nerve .
although patients usually suffer from serious pain , this patient did not have so strong pain , she could relieve of pain by nonsteroidal anti - inflammatory drugs and she has not developed postherpetic neuralgia .
also , the failure of her immune system was not the result of underlying disease which compromised immune system but a result of other reasons .
herpes zoster may involve any nerve in human body with characteristic skin rash in the area of its innervations .
it does not have to be a consequence of serious underlying diseases ; the failure of immune system may be the result of overwork , emotional stress or inappropriate nutrition . | introduction : herpes zoster is an acute , cutaneous viral infection caused by the reactivation of varicella - zoster virus ( vzv ) that is the cause of varicella . it is an acute neurological disease which can often lead to serious postherpetic neuralgia ( phn ) .
different nerves can be included with the skin rash in the area of its enervation especially cranial nerves ( cv ) and intercostal nerves.case report : in this report we present a patient with herpes zoster which involved ulnar nerve with skin rash in the region of ulnar innervations in women with no disease previously diagnosed .
the failure of her immune system may be explained by great emotional stress and overwork she had been exposed to with neglecting proper nutrition in that period.conclusion:herpes zoster may involve any nerve with characteristic skin rash in the area of its innervations , and failure in immune system which leads reactivation of vzv may be caused by other factors besides the underlying illness . |
efficient and tightly controlled leukocyte transendothelial migration ( tem ) is of key importance in physiological processes such as immune surveillance and acute inflammation .
uncontrolled and excessive tem is characteristic for various disorders such as chronic inflammatory diseases ( e.g. , rheumatoid arthritis , atherosclerosis , asthma ) and tumor cell metastasis . in order to specifically interfere with excessive leukocyte or tumor cell tem , a detailed understanding of endothelial signaling that regulates tem is required .
butcher and springer proposed in timeless reviews the multi - step model for the process of tem .
currently , the basis of this model is still accurate and some additional steps have been included ( fig . 1 ) .
the group of alon described the need for the presence of immobilized chemokines on the surface of the endothelium .
recently , they showed that the endothelium itself generates chemokines and presents those at the apical surface to promote tem .
barreiro and colleagues , together with carman and co - workers , showed the contribution of cup - like membrane structures created by the endothelium that surround adherent leukocytes in order to facilitate directional transmigration .
nevertheless , the main steps of tem , namely rolling , adhesion , and transmigration , as proposed by butcher and springer more than 20 years ago , still constitute the central processes that drive leukocyte extravasation ( fig . 1 ) .
step 1 represents the rolling and tethering phase ; step 2 shows the initial adhesion of the leukocytes to the endothelium .
the cup - like structures are formed , resulting in step 5 ; actual transmigration , either para- or transcellular . in this review ,
we discuss the regulatory mechanisms that control the different steps of leukocyte extravasation ( fig .
1 ) from an endothelial point of view , with specific focus on the role of the rho - gtpases and their activators guanine - nucleotide exchange factors ( gefs ) .
initially , transient leukocyte endothelial cell interactions are mediated by the endothelial adhesion molecules e- and p - selectin with their leukocyte counterparts l - selectin and psgl-1 .
these interactions comprise the so - called rolling step ; slowing down the leukocytes on the endothelial cell surface ( fig .
1 , step 1 ) . p - selectin , also known as cd62p , is present in weibel - palade bodies and can be quickly released and presented at the luminal side of the endothelium upon activation with histamine / thrombin or with pharmacological compounds such as ca ionophores or phorbol esters .
maximal expression of p - selectin on the endothelial surface is seen after 10 min of activation , after which ( 3060 min ) the protein is being downregulated , either by internalization or shedding .
cd63 was found to be an essential co - factor for p - selectin , since endothelial cells deficient for cd63 showed a loss of p - selectin - mediated adhesion function .
e - selectin ( cd62e ) is not found in weibel - palade bodies , but is rapidly upregulated by inflammatory stimuli , such as tnf- and il1. as for p - selectin , the upregulation involves the small rho - gtpases rhoa , rhob , and rac1 .
interestingly , clustering of e- and also p - selectin , using crosslinking of antibodies , induced intracellular signals into the endothelium , including a remodeling of actin stress fibers .
the authors also reported that initial leukocyte adhesion to the endothelium induced an immediate increase in calcium concentrations in the endothelium , in line with the role of selectins , mediating initial interaction of the leukocytes with the endothelium .
additionally , clustering of e - selectin has been shown to redistribute e - selectin to caveolin - rich membrane domains and promote its interaction with and activation of phospholipase c. moreover , e - selectin clustering also triggers the activation of erk1/2 and expression of c - fos , as well as changes in the endothelial cell morphology and f - actin distribution , in line with the work by lorenzon and colleagues .
in fact , clustering of e - selectin induced by monocytes was dependent on upstream rhoa activation .
additionally , e - selectin clustering induced a linkage to the actin cytoskeleton through its intracellular tail .
yoshida and co - workers showed the presence of actin - associated proteins -actinin , vinculin , filamin , fak , and paxillin , but not talin , in e - selectin - clustering precipitation assays .
this was measured by applying mechanical stress to the endothelial cells using anti - e - selectin antibody - coated ferromagnetic beads with a magnetical twisting cytometer .
these data suggested that actin remodeling is instrumental for proper e - selectin function and strongly suggests a prominent role for small rho - gtpases .
and although rho - gtpases have been implicated upstream from p- and e - selectin , so far no role for rho - gtpase signaling downstream from either p- or e - selectin during step 1 of tem has been reported . in the next section , we will discuss the endothelial signaling during step 2 and 3 in more detail .
firm adhesion of leukocytes is initiated upon binding of activated integrins to their endothelial ligands intercellular adhesion molecule 1 ( icam-1 ) and vascular cell adhesion molecule ( vcam-1 ) . to demonstrate the importance of icam-1 in firm adhesion and tem , chinese hamster ovary ( cho ) , or hela cells that expressed no or very little endogenous icam-1 were artificially transfected with icam-1 .
this was sufficient to recapitulate the entire process of neutrophil adhesion and migration across these cells ( van buul jd , data not shown ) .
the group of silverstein showed that leukocyte adhesion to endothelial cells induced the release of intracellular calcium in endothelial cells although the upstream signals , i.e. , selectin- or cam - mediated , were unknown at that time .
nevertheless , they were the first to show the importance of intracellular signaling in endothelial cells during the adhesion step of leukocyte tem .
this is both a passive and an active event . icam-1 and vcam-1 reside in preformed membrane nanodomains ( also termed endothelial adhesive platforms ) that are controlled by several members of the tetraspanin family of integral membrane proteins .
leukocyte binding to the endothelium through the engagement of integrins induces these nanodomains to coalesce into higher order clusters , leading to the activation of several signaling pathways in endothelial cells .
it is now well recognized that this signaling , in turn , activates positive feedback loops , promoting additional clustering of ig - cams like icam-1 and vcam-1 into ring - like structures around adherent leukocytes , which subsequently amplifies signaling through a positive feedback loop .
the carboxyl ( c)-terminal intracellular domain of icam-1 is relatively small ( 28 amino acids ) compared with its extracellular region ( 481 aa ) .
nevertheless , signaling by icam-1 was shown to be dependent on this small intracellular domain .
also , vcam-1 shows a relatively small c - terminal intracellular domain compared with its extracellular domain ( 19 vs. 699 aa , respectively ) . since the c - terminal domains of these proteins do not contain any apparent signaling motifs , signaling is likely relayed via adaptor proteins .
several adaptor proteins have been reported to interact with the intracellular domains of icam-1 and vcam-1 , including -actinin , cortactin , filamin , and members of the erm protein family . besides acting as scaffolding proteins , these adapters are also able to bind actin , and can therefore anchor icam-1 and vcam-1 physically to the actin cytoskeleton .
early studies showed that leukocyte adhesion and clustering of icam-1 promote an increase in intracellular ca levels .
others followed up on this crucial finding and showed that the change in calcium concentration leads to activation of the tyrosine kinase src by protein kinase c ( pkc ) . in turn
, src induces tyrosine phosphorylation of focal adhesion proteins , such as paxillin , cortactin , and fak .
the group of luscinskas underscored the importance of endothelial src - mediated phosphorylation of cortactin in leukocyte tem .
they showed that a non - phosphorylatable mutant of cortactin , expressed in endothelial cells , blocked leukocyte tem .
in addition , icam-1 clustering leads to the activation of the small gtpase rhoa , which stimulates the formation of f - actin stress fibers .
moreover , rhoa activity was also demonstrated to be required for efficient icam-1 recruitment around adherent monocytes , suggesting an upstream role for rhoa within the icam-1-induced signaling cascade .
interestingly , others have shown that thrombin - induced rhoa activation , resulting in increased stress fibers , showed loss of cell cell contacts and increased gap formation in endothelial cells . however
, high rhoa activity and increased stress fibers downstream from icam-1 clustering did not necessarily result in endothelial gap formation .
this indicates that the consequences of the intracellular signals that lead from rhoa activation to cell cell junctions in endothelial cells specifically depend on the extracellular stimulus .
although guanine nucleotide exchange factors ( gefs ) are likely candidates to activate rhoa downstream from icam-1 engagement , no direct rhoa
etienne and colleagues showed that the rap1gef c3 g binds to cas upon antibody - induced clustering of icam-1 .
they additionally indicated no role for the ras- and rac1-gef sos-1 downstream from icam-1 in their model system .
interestingly , rhoa can also be directly activated in a gef - independent manner by reactive oxygen species ( ros ) .
aghajanian and co - workers demonstrated that ros can directly target two critical cysteine residues that are located in a unique redox - sensitive motif within the phosphoryl binding loop of rhoa , resulting in rhoa - gtp loading .
clustering of vcam-1 was shown to promote activation of the gtpase rac1 , leading to the production of ros .
vcam-1-dependent ros production was demonstrated to regulate the activation of matrix metalloproteases , which may contribute to the local breakdown of the endothelial adherens junctions .
in addition , vcam-1 clustering was shown to regulate lymphocyte tem by activation of the kinase pkc and the tyrosine phosphatase ptp1b in a ros - dependent manner .
more recently , it was shown by the group of vestweber that vcam-1-induced rac1 activation and subsequent ros production was also involved in the dissociation of the endothelial receptor phosphatase ve - ptp from the junctional adhesion molecule ve - cadherin , which is an obligatory event during leukocyte tem .
more recent advances in confocal microscopy have allowed detailed analysis of leukocyte endothelium interactions in three dimensions .
this revealed that upon clustering , both icam-1 and vcam-1 were recruited to cup - like , f - actin - rich membrane protrusions that surround adherent leukocytes ( step 4 ) . in the next section
, we will discuss the signaling and function that underlies the formation of these structures .
barreiro and co - workers were the first to report on the induction of these f - actin rich cups . using live - cell imaging , they showed that adhesion and spreading of lymphoblasts on the endothelial cell surface induced the recruitment of vcam-1 and the erm - family member moesin , whereas icam-1 and moesin recruitment were primarily observed during tem .
in addition , adhesion of k562 cells that were stably transfected with 4 integrin ( 4m7 cells ) resulted in an actin - rich endothelial cup structure embracing the 4m7 cells , and contained icam-1 , vcam-1 , moesin , ezrin , -actinin , vinculin , and vasp .
phospho - inositides and the rho - rock - pathway were involved in the generation and maintenance of these so - called docking structures .
initially , barreiro and colleagues proposed that the structures are essential during the docking or adhesion phase and may protect leukocytes from detachment by shear flow , hence the term docking structures .
, who demonstrated using in vivo studies that removal of one of the crucial players involved in docking structure formation reduced leukocyte adhesion . however , although docking structures are formed around adhering leukocytes , it is still under debate whether or not these structures function in strengthening the adhesion of the leukocyte to the endothelium .
several reports have shown that inhibition of icam-1 signaling , and thus , preventing docking structure formation in vitro , affects leukocyte tem , but not adhesion .
in fact , carman and colleagues revealed that the endothelium pro - actively generates microfilament , microtubule , and calcium - dependent icam-1-enriched cup - like structures within minutes of binding to lfa-1-bearing leukocytes .
interestingly , disruption of endothelial projections by blocking actin polymerization ( cytochalasin d ) or microtubule polymerization ( colchicine ) , or by chelating calcium ( bapta ) did not affect firm adhesion of leukocytes .
thus , from this work , these structures appear not to function in adhesion strengthening , but may in fact play a more direct role in the final diapedesis step . to assess the role of rho - gtpases in the formation of these endothelial actin - rich projections , carman and colleagues treated the endothelial cells with clostridium diffucile toxin - b to inhibit rho , rac1 , and cdc42 .
toxin - b treatment was associated with a 2-fold reduction in total projections and tem .
in contrast to the docking structures proposed by barreiro and co - workers , blocking rho by c3 transferase had no effect on either projections or tem .
these data suggest an active role for the rho - gtpases rac1 and cdc42 in projection formation and provide correlative support for a functional role of projections in leukocyte diapedesis .
a year later , the carman lab demonstrated a cup - like structure that is formed around transmigrating leukocytes in both the paracellular and transcellular migration pathway .
again , blocking rho - kinase ( by y27632 ) or rho ( by c3 ) did not prevent cup formation downstream from icam-1 engagement .
the structure contained high icam-1 and vcam-1 and was enriched for vertical microvilli - like structures .
leukocyte integrins were redistributed into linear tracks oriented in parallel to the direction of diapedesis .
carman and co - workers proposed that docking structures may promote diapedesis by providing additional membrane surface to provide directional guidance to leukocytes for transmigration , and hence , proposed the term transmigratory cups . alternatively , the group of kubes demonstrated in vivo that during neutrophil tem , docking structures develop into dome - like structures , which completely encapsulate the neutrophil .
they additionally showed that when dome formation was inhibited by silencing the expression of the f - actin - binding protein lsp1 , vascular leakage during neutrophil diapedesis was increased .
they therefore proposed that endothelial domes may function to seal off the transmigrating leukocyte in order to minimize vascular leakage during extravasation .
it is interesting to note that several molecular players in the formation of endothelial cup structures , such as rac1 , cortactin , and filamin , were also reported to be important for maintaining endothelial monolayer integrity .
it is therefore possible that activation or recruitment of these molecules during leukocyte tem may have a dual purpose by promoting diapedesis , and at the same time maintaining endothelial barrier integrity , although proof for this hypothesis is currently lacking . the formation of the endothelial cup - like structure shows several similarities with the formation of the so - called phagocytic cup . also , the role of the rho - gtpase rhog in the phagocytosis of apoptotic cells and its specific exchange factor sh3-containing gef ( sgef ) in macropinocytosis show similar functions in both processes .
this was the rationale to examine if rhog and sgef may contribute to the formation of endothelial cups and participate in tem .
subsequently , this results in src - dependent activation of rhog , leading to the formation of apical cup assembly .
specifically , sgef binds to icam-1 via its sh3 domain and silencing of endothelial sgef or rhog decreased cup formation and inhibited leukocyte tem , but did not affect leukocyte adhesion .
recently , schnoor and co - workers showed that icam-1-induced activation of rhog required cortactin .
interestingly , the icam-1/sgef interaction was independent of icam-1 clustering . however , using nucleotide - free gst mutants of rhog to measure gef activity , we found that icam-1 clustering did activate sgef ( jdvb , data not shown ) . using a sgef - deficient mouse line , samson and
colleagues showed that sgef deficiency resulted in reduced on - set of atherosclerosis , most likely by the inability of the vasculature to form proper cup - like structures and prevent leukocyte tem .
these data suggest that the rhog / sgef signaling axis is one of the central mediators of cup - structure formation .
the work by carman and colleagues suggested a role for the small gtpase rac1 downstream from leukocyte adhesion .
when measuring rac1 activation downstream from icam-1 clustering , in parallel with rhog activation , it became clear that rac1 activity preceded rhog activation .
this indicated that , next to sgef , which activates rhog , another gef is activated downstream from icam-1 clustering .
our initial data showed that icam-1 , when clustered , interacted with the actin - adaptor protein filamin .
also , debakker and colleagues showed that trio activates rhog to allow phagocytosis of apoptotic cells .
moreover , next to rhog , this gef was also able to activate rac1 and rhoa , two gtpases known to be involved in downstream icam-1 signaling .
additional data from our laboratory showed that depletion of rac1 or rhog reduced tem of primary neutrophils .
rac1 depletion showed defects in actual icam-1 clustering , and rhog depletion impaired the induction of cup structures .
these data implicate that rac1 and rhog have separate functions to induce endothelial cup structures upon leukocyte binding ( fig . 2 ) .
figure 2 . the cup - like structure . signaling routes that are initiated by clustering of icam-1 and
result in the remodeling of the actin cytoskeleton and the formation of cup - like structures .
signaling includes the activation of the small gtpases rac1and rhog downstream from icam-1 clustering and involvement of at least two gefs , trio and sgef .
additionally , rac1 activation may result in a positive feedback loop , increasing the clustering of icam-1 . additionally ,
trio binds to the intracellular tail of icam-1 via regions located in the n - terminal gef domain .
however , reduced filamin expression in endothelial cells did prevent icam-1-induced rac1 and rhog activation . moreover , also icam-1-induced trio activation , measured through its binding to the nucleotide - free gtpase mutants ( rac1-g15a / rhog - g15a ) , was impaired in filamin - deficient cells .
so , although filamin did not regulate the binding of trio to icam-1 , it did control downstream gtpase activity , probably through other signaling molecules such as src - family kinases .
one of the drawbacks of the above - described study is the use of artificial anti - icam-1 antibody - coated beads to cluster icam-1 .
it is therefore good to note that the kinetics of icam-1 clustering in these experiments may differ from icam-1 signaling during leukocyte diapedesis .
in fact , from the time - point of firm adhesion , neutrophils take approximately 100 s to cross the endothelium .
thus , the real - time temporal and also spatial activation of rac1 and rhog during neutrophil tem remains an open question . as mentioned above ,
the different steps in the formation of endothelial cup - like structures are reminiscent of the process of phagocytic cup formation by phagocytic cells .
formation of a phagocytic cup is initiated by a local coalescence of f - actin in a ring - like structure , followed by membrane protrusion around the opsonized cell or particle .
although we never observed complete closure and fusion of membrane protrusions during docking structure formation in vitro , others have reported in vivo docking structures advancing into dome - like structures , completely covering the transmigrating leukocyte .
interestingly , similar molecular players , including the gtpases rhog , rac1/2 , ccd42 , rhoa and gefs trio , and sgef were reported to regulate phagocytosis or related processes such as macropinocytosis , suggesting that cells use analogous signaling pathways . using fret - based biosensors for rac1 , rac2 , and cdc42 ,
it is therefore tempting to speculate that also within a docking structure rhog , rac1 , and rhoa are distinctly spatially activated , with rhoa activation at the base of the cup , followed by rac1 at the base and leading edge of the cup , and rhog within the membrane protrusions .
previous work to delineate the role of gtpase signaling in leukocyte tem was primarily based on inhibitor studies , knockdown studies , or biochemical assays such as classical gtpase pull - down or pull - down assays using nucleotide - free gtpase mutants . to date
, genetically encoded fret - based biosensors of rho - gtpases would be the best tool to delineate the fast and local kinetics of rho - gtpase activation in endothelial cells during leukocyte tem .
overall , it is evident that endothelial signaling is essential to initiate the final step of the tem process : transmigration .
to breech the endothelial barrier , leukocytes can take two different routes : ( 1 ) paracellular , i.e. , through the endothelial cell cell junctions or ( 2 ) transcellular , i.e. , through the endothelial cell body ( fig . 1 ,
however , what signal determines to finally transmigrate across the endothelium and by which pathway ?
first , shear stress has been suggested to be an important initiator of diapedesis . although shear clearly plays an important role in tem and triggers diapedesis , robust diapedesis
is also observed in the absence of shear . for more information on the role of shear stress on tem
second , central - to - peripheral expression gradients of adhesion molecules , such as pecam-1 , cd99 , and jams , have been proposed to direct leukocytes to those sides to provide the required traction to drive diapedesis at these locations . in addition , chemokines presented at the luminal surface of the endothelium may also drive diapedesis through cell cell junctions by using similar gradients as the adhesion molecules . for instance ,
il-8 and rantes have been shown to be distributed apically on endothelial microvilli in vivo .
recently , it has been shown that perivascular macrophages , lining pericytes that cover blood vessels , locally secrete chemokines that cause local
third , the spatial and temporal recruitment of adhesion molecules upon leukocyte binding , followed by their interactions with cytoskeletal components , induce signals in the endothelium , resulting in actin - rich structures that embrace adherent leukocyte , i.e. , cup - like structures ( step 4 ) , and may provide directional guidance to leukocytes for diapedesis .
the dynamic distribution of endothelial and leukocytic adhesion molecules with the actin cytoskeleton during tem was first studied by martin sandig and co - workers .
they identified a circular structure in endothelial cell cell contact regions that facilitates leukocyte diapedesis .
additionally , they noticed that leukocytes induced lfa-1-containing pseudopodia that penetrated in between endothelial cells . at sites of diapedesis ,
high levels of lfa-1 and f - actin were found , suggesting a major role for these molecules in tem .
they showed that upon transmigration , lfa-1 was rapidly redistributed in a ring - like structure together with icam-1 .
the redistribution and co - clustering of icam-1 and lfa-1 was also demonstrated by the group of carman .
in fact , they showed that invasive podosomes from leukocytes initiate transcellular migration , i.e. , through the endothelial cell body .
sandig and co - workers furthermore showed that endothelial adherence junction proteins were locally redistributed at sites of leukocyte diapedesis , but the ve - cadherin complex , judged by ve - cadherin and -catenin co - localization , remained intact during diapedesis .
our previous work underscored that junctional proteins like ve - cadherin are locally dispersed upon passage of leukocytes .
additionally , su and co - workers demonstrated differential movement of ve - cadherin and pecam-1 upon leukocyte passage .
whereas these authors underscored the local redistribution of ve - cadherin , they additionally showed that pecam-1 forms a ring - like structure upon diapedesis .
these data show that , next to endothelial cell adhesion molecules , junctional proteins can be differently regulated during the final tem step , and therefore , may be involved in the final decision when and where leukocytes cross .
remarkable little vascular leakage occurs when leukocytes cross the endothelium through the cell cell junctions .
however , under certain patho - physiological conditions such as chronic inflammation , leakage is increased . to be able to interfere with this effect ,
recently , martinelli and co - workers provide a mechanism by which endothelial cells maintain their barrier function during leukocyte transendothelial migration . in response to m - scale disruptions induced by transmigrating leukocytes , endothelial cells generate unique ventral lamellipodia that close these small gaps in the endothelium . these ventral lamellipodia were enriched in rac1 effectors cortactin , iqgap , and p47phox .
they propose that barrier disruptions are detected as local release of isometric tension and unloading of force , which is directly coupled to ros - dependent self - restorative membrane protrusions .
closing the gap after leukocyte passage is one thing , opening the junctions to allow crossing is another .
although several papers have described the importance of icam-1-induced phosphorylation of ve - cadherin , possibly through src - like kinases , leading to the opening of ve - cadherin - mediated cell
9295 ) , we focused in this section on the potential role of endothelial tension in the final step of tem .
hixenbaugh and colleagues showed that fmlp - stimulated neutrophils induced phosphorylation of endothelial myosin light chain ( mlc ) on t18/s19 that was mediated by the calcium / calmodulin - regulated enzyme mlc - kinase . in turn , mlc - kinase facilitated the interaction of myosin with the actin cytoskeleton , leading to the actomyosin contractile responses and increased tension in endothelial cells .
they proposed that increased endothelial contraction and generation of isometric tension may function as a mechanism by which endothelial cells open their intercellular junctions , thereby facilitating leukocyte tem ( fig .
adherent neutrophils measured under static conditions induce cytoskeletal rearrangements in the form of stress fibers and increase pmlc after 30 min .
inhibition of the calcium calmodulin - regulated enzyme mlc - kinase ( by kt-5926 or ml-9 ) or treatment with the calmodulin antagonist trifluoperazine reduced pmn transendothelial migration toward a leukotriene b4 chemotactic gradient , indicating that the cytoskeletal rearrangements were depending on calcium signaling . when endothelial cells were treated with calyculin , a myosin - phosphatase inhibitor , increasing mlc phosphorylation , this resulted in increased endothelial cell contraction , paracellular gap formation , and enhanced neutrophil tem .
in addition , inhibition of the endothelial rho / rock pathway , using c3 or y-27632 , significantly reduced actin polymerization , myosin ii filament formation , mlc phosphorylation , and neutrophil tem , suggesting that rho / rock regulate tem through the control of mlc activity .
however , one should take in account that these assays were all done under static conditions .
also , the initial trigger to induce mlc phosphorylation downstream from leukocyte adhesion is not known .
leukocyte adhesion results in the induction of actin - myosin contractility , as depicted in the figure , through the rho - rock pathway or calcium signaling , resulting in mlc phosphorylation .
this may finally result in the opening of cell cell junctions , and thus , be involved in facilitating leukocyte tem .
recently , the group of chen showed that monocytes induced traction force onto the endothelial cells .
interestingly , the forces were measured in the endothelial cell to which a single monocyte was adhering to . moreover ,
the increased endothelial traction force was measured in the sub - cellular zone of monocytes adhesion .
thus , the above - discussed results suggest that leukocytes can directly induce signals into a single endothelial cell that in turn induce actin - mediated forces .
in fact , liu and colleagues used beads that were coated with anti - icam-1 and anti - vcam-1 antibodies . using these beads they noticed similar traction forces , indicating that these signals are indeed submitted through icam-1 and vcam-1 and induced by clustering .
potentially , this process can be involved in opening endothelial cell cell junctions , and thus , in facilitating leukocyte tem .
remarkable little vascular leakage occurs when leukocytes cross the endothelium through the cell cell junctions .
however , under certain patho - physiological conditions such as chronic inflammation , leakage is increased . to be able to interfere with this effect ,
recently , martinelli and co - workers provide a mechanism by which endothelial cells maintain their barrier function during leukocyte transendothelial migration . in response to m - scale disruptions induced by transmigrating leukocytes , endothelial cells generate unique ventral lamellipodia that close these small gaps in the endothelium . these ventral lamellipodia were enriched in rac1 effectors cortactin , iqgap , and p47phox .
they propose that barrier disruptions are detected as local release of isometric tension and unloading of force , which is directly coupled to ros - dependent self - restorative membrane protrusions .
closing the gap after leukocyte passage is one thing , opening the junctions to allow crossing is another .
although several papers have described the importance of icam-1-induced phosphorylation of ve - cadherin , possibly through src - like kinases , leading to the opening of ve - cadherin - mediated cell cell junctions , and thereby , facilitating tem ( reviewed in refs .
9295 ) , we focused in this section on the potential role of endothelial tension in the final step of tem .
hixenbaugh and colleagues showed that fmlp - stimulated neutrophils induced phosphorylation of endothelial myosin light chain ( mlc ) on t18/s19 that was mediated by the calcium / calmodulin - regulated enzyme mlc - kinase . in turn , mlc - kinase facilitated the interaction of myosin with the actin cytoskeleton , leading to the actomyosin contractile responses and increased tension in endothelial cells .
they proposed that increased endothelial contraction and generation of isometric tension may function as a mechanism by which endothelial cells open their intercellular junctions , thereby facilitating leukocyte tem ( fig .
adherent neutrophils measured under static conditions induce cytoskeletal rearrangements in the form of stress fibers and increase pmlc after 30 min .
inhibition of the calcium calmodulin - regulated enzyme mlc - kinase ( by kt-5926 or ml-9 ) or treatment with the calmodulin antagonist trifluoperazine reduced pmn transendothelial migration toward a leukotriene b4 chemotactic gradient , indicating that the cytoskeletal rearrangements were depending on calcium signaling . when endothelial cells were treated with calyculin , a myosin - phosphatase inhibitor , increasing mlc phosphorylation , this resulted in increased endothelial cell contraction , paracellular gap formation , and enhanced neutrophil tem .
in addition , inhibition of the endothelial rho / rock pathway , using c3 or y-27632 , significantly reduced actin polymerization , myosin ii filament formation , mlc phosphorylation , and neutrophil tem , suggesting that rho / rock regulate tem through the control of mlc activity . however , one should take in account that these assays were all done under static conditions . also , the initial trigger to induce mlc phosphorylation downstream from leukocyte adhesion is not known .
leukocyte adhesion results in the induction of actin - myosin contractility , as depicted in the figure , through the rho - rock pathway or calcium signaling , resulting in mlc phosphorylation .
this may finally result in the opening of cell cell junctions , and thus , be involved in facilitating leukocyte tem .
recently , the group of chen showed that monocytes induced traction force onto the endothelial cells .
interestingly , the forces were measured in the endothelial cell to which a single monocyte was adhering to . moreover ,
the increased endothelial traction force was measured in the sub - cellular zone of monocytes adhesion .
thus , the above - discussed results suggest that leukocytes can directly induce signals into a single endothelial cell that in turn induce actin - mediated forces .
in fact , liu and colleagues used beads that were coated with anti - icam-1 and anti - vcam-1 antibodies . using these beads they noticed similar traction forces , indicating that these signals are indeed submitted through icam-1 and vcam-1 and induced by clustering .
potentially , this process can be involved in opening endothelial cell cell junctions , and thus , in facilitating leukocyte tem .
from the above - discussed data , it is clear that endothelial rho - gtpases play an essential role in the process of transendothelial migration by remodeling the actin cytoskeleton . in particular in step 2 to 5 , rho - gtpase signaling is critical to remodel the actin cytoskeleton to induce membrane protrusions , i.e. , cup - like structures and support leukocyte - induced tension force in order to open or close the cell cell junctions or gaps through which leukocytes have crossed .
future challenges remain to investigate the spatial and temporal activation of the rho - gtpases during the different steps of tem , and which gefs are locally activating these gtpases . | leukocyte transendothelial migration ( tem ) is one of the crucial steps during inflammation . a better understanding of the key molecules that regulate leukocyte extravasation aids to the development of novel therapeutics for treatment of inflammation - based diseases , such as atherosclerosis and rheumatoid arthritis .
the adhesion molecules icam-1 and vcam-1 are known as central mediators of tem .
clustering of these molecules by their leukocytic integrins initiates the activation of several signaling pathways within the endothelium , including a rise in intracellular ca2 + , activation of several kinase cascades , and the activation of rho - gtpases .
activation of rho - gtpases has been shown to control adhesion molecule clustering and the formation of apical membrane protrusions that embrace adherent leukocytes during tem . here
, we discuss the potential regulatory mechanisms of leukocyte extravasation from an endothelial point of view , with specific focus on the role of the rho - gtpases . |
what i have heard is very different from what i am accustomed to hearing from my training in terms of palliative care .
one of the things that bothered me a lot about bringing up palliative care , and i was one of the most aggressive residents about doing this , was that patients had to sign a form saying they understood that they would no longer be getting certain aspects of care .
your presentation gave the impression that palliative care can be applied much earlier , and even as part of regular ongoing treatment , which sounds terrific to me .
when i was in the hospital , i had the sense that the palliative care team was the only group of people who are advocating for patients or family members with the day - to - day problems such as getting blood drawn every 30 minutes , getting woken up 20 times a night , and other things that just make life in the hospital miserable .
are there ways palliative medicine can address some of these more practical issues ? and how does it work ?
it seems very awkward when the team that is dealing with the acute problems is the one asking for blood every 30 minutes .
mir s response : it is very important to know that we , as palliative care team , have a very big role in the hospital .
we have to speak to the patient and the family and conduct a family meeting .
the next goal is to speak to the physicians and the consultants and having a series of grand rounds for the subspecialties : the cardiologists , heart failure specialists , and neurologists .
unfortunately , we have a specialty for each system and each disease of the body .
i think it is a very productive exercise in the sense that a lot of questions are answered , and the subspecialists are able to understand what we do in a better sense .
we collaborate with them because we tell them that we are meeting the family of a patient .
we recently had a very sad case of west nile virus with multiorgan failure , and in the patient s family there were two health - care workers whom we knew closely .
the patient s wishes were clear about not having life - sustaining therapies , but he did not have the capacity at the time to make this known . through the negotiation of goals of care , the only way we could deliver what was needed to the family was to have the neurologist in the room to present all the information we could , both from centers for disease control and prevention and from the new york state department of health .
we asked the family members what they wanted and what kind of outcomes they were looking for .
it does not limit therapies ; for example , palliative care can partner with oncology care .
hospice has open - access , which means hemodialysis or palliative chemotherapy can be offered under the hospice benefit .
as long as the focus is symptom palliation , we do whatever it takes to make that patient comfortable .
dr . mir s response : the hospice benefit recommends that patient sign a waiver to forego aggressive treatment .
smith pointed out that hospice gets paid $ 174 a day to cover certain services .
those services are for durable medical equipment , including a bed , oxygen , and whatever else is needed , including lab tests and nurse visits .
they include wound care , which may be daily , and may include hydration and nutrition . therefore , the cost may be way beyond $ 174 .
it is a balancing act to see what is appropriate for each patient and trying to individualize the plan of care .
clearly , a time will come that we will have programs or plans for medicare , which is called bridge to hospice .
i think the data from the new england journal of medicine s article will show that we can have good palliation and good symptom control along with chemotherapy in improving the patients outcomes . | health care should make an attempt to understand the different religious principles that affect end - of - life decisions in patient care
. with advanced illness , defining an ethical framework is essential to understanding sensitive issues .
compassionate care is crucial in all end - of - life care settings .
physician awareness is a key principle in inculcating the religious values of patients .
cultural and religious awareness on the part of the health - care team is needed to provide patients with effective end - of - life palliative and hospice care . |
arterial puncture occurs at the start of angiography and interventional radiology , and is a
very important factor determining the success or failure of successive procedures . recently
,
this procedure has been performed by a range of approaches depending on the type of surgery ,
e.g , through the radial artery . until now
, the procedure through the femoral artery has been
used most widely as the most basic puncture area for angiography . on the other hand ,
hemostasis and
the pertinent complications are problems in the femoral artery , in which the
pressure is high after the procedure and the size of the blood vessels is relatively
high .
therefore , hemostasis in the puncture area for angiography or interventional radiation is a
very important last step of the procedure .
the methods of hemostasis for the femoral artery
include manual compression , which is the removal of the sheath and compression with the
hands , and methods that apply compression devices1 . of these
, manual compression requires absolute bed rest for a few
hours . on the other hand
, the level of patient discomfort is increased due to lengthy bed
rest and the restriction of walking .
moreover , hematoma in the punctured area of blood
vessels , formation of a pseudoaneurysm , and vascular occlusions develop in approximately
15% cases2 , 3 .
a variety of hemostasis devices have been developed to treat these
complications that allow for rapid recovery of patients from bed rest .
these include
angio - seal device ( collagen sponge and copolymer anchor ) and percutaneous placement of a
device ( prostar ) that utilizes two nonabsorbable sutures ( perclose , redwood city , ca , usa ) .
the angio - seal device uses a method of adsorption with a collagen sponge placed within the
blood vessels .
the prostar device uses a method in which the blood vessels are sutured4 , 5 .
these hemostasis devices can reduce the discomfort and the time to hemostasis ( clotting
time ) in the puncture area when used in patients , who can not lie down in bed for a long time
or in patients with low platelet values who have received anti - coagulation treatments .
therefore , they allow rapid walking , which shortens the hospitalization period of the
patient . at the time of hemostasis , however , hematoma or complications of peripheral blood
vessels can occur , and several problems , such as a long time to hemostasis , can develop in
patients who have received urokinase and in obese patients . therefore , this study examined the change in complications or success rate of hemostasis
according to the hemostasis method .
patients , who had received angiography after femoral
arterial puncture and hands , or a combination of manual compression and , were enrolled in
this study .
the subjects were 180 patients who underwent angiography after femoral arterial puncture
from november 2010 to august 2011 .
the highest
proportion of patients were between 50 and 60 years of age ( 48% , 44 cases ) .
the distribution of age and gender of the patients ( n = 180)gendertotal ( % ) malefemale30s17724 ( 12.2)40s211334 ( 17.7)50s311243 ( 23.3)60s371047 ( 25.5)70s26632 ( 17.7)total ( % ) 132 ( 73.3)48 ( 26.4)180 ( 100.0 ) ) . in 60 of the patients ( group a : 52.2 9.83 years , 41 males , 19 females ) ,
femoral arterial hemostasis had been performed after angiography using an angio - seal device
( st .
jude medical europe , belgium ) , and compression was performed with a compression device .
for another 60 patients ( group b : 50.7 11.23 years , 47 males , 13 females ) , after
angiography
, hemostasis was performed by compressing the puncture area with the hands . for
the remaining 60 patients ( group c : 54.27 12.21 years , 44 males , 16 males ) , after
angiography , femoral arterial hemostasis was performed using an angio - seal device and a
compression device , and the puncture area was then compressed again with the hands . among
the patients who had undergone angiography , those who did not receive a blood test , those
who presented with pain during hemostasis , those whose conditions
were unstable , and those
whose times to hemostasis were not accurate were excluded .
all participants signed a written
informed consent form approved by the institutional review board at the university of
soonchunhyang . for group a , femoral arterial angiography was without abnormal findings immediately after
angiography , such as stenosis of blood vessels and , arterial detachment , an angio - seal
device was placed in the puncture area of the blood vessel , and a compression device
( easy - stop , tae woong , seoul , republic of korea ) was used ( for compression , refer to fig .
an angio - seal device ( a ) was placed in the puncture site of the blood vessels , and
the site was compressed using a compression device ( b ) . ) . for group
b , after angiography , the sheath inserted into the femoral artery was
removed , and the puncture area was compressed with the hands . for group c , immediately after
angiography , an angio - seal device was placed in the puncture area of the blood vessel , and
the puncture area was compressed for approximately 10 min using a compression device and
then compressed with the hands . an angio - seal device ( a ) was placed in the puncture site of the blood vessels , and
the site was compressed using a compression device ( b ) . in each group , after performing angiography , the effect of gender , the time to hemostasis
of each generation , the results of blood correlation between hemoglobin value , platelet
value , and the time to hemostasis were examined .
in addition , the frequency of complications
according to the hemostasis methods of each group and incidence were compared .
complications
were defined as the development of a hematoma > 5 cm , and a decrease in the hemoglobin
level to < 3 g / dl .
a questionnaire was used to assess the presence or absence of pain
after hemostasis . the time to hemostasis after angiography of each group
, post hoc analysis was performed using a scheffe s test . through
this , the gender of each group and the time to hemostasis of each generation were compared
and analyzed .
the pearson correlation coefficient was applied to determine the correlation
between the hemoglobin value , platelet value , and time to hemostasis .
frequency analysis and
anova were applied to examine the development frequency of complications according to the
hemostasis method of each group and the incidence and frequency . the spss statistical
software ( spss , 17.0 , chicago , il , usa ) was applied for statistical analysis .
in addition , cases with a
pearson correlation coefficient > 0.5 were considered to be correlated .
the mean ages of groups a , b , and c were 52.2 9.83 , 50.7 11.23 , and 54.27
12.21 years , respectively ; there was no significant difference between the three groups .
the
male to female ratios in groups a , b , and c were 68.33%:31.66% , 78.33%:21.66% , and 73.33% :
26.66% , respectively .
the type of tests ,
hemoglobin , and platelet values were also similar in the three groups ( table 2table 2 .
baseline clinical characteristics ( n = 180)group a ( n=60)group b ( n=60)group c ( n=60)age ( mean sd)52.2 9.8350.7 11.2354.27 12.21male ( % ) 68.3378.3373.33female ( % ) 31.6621.6626.66type of examinationhepatic angiography ( % ) 8 ( 13.33%)5 ( 8.33%)9 ( 10.5%)tfca ( % ) 25 ( 41.66%)22 ( 36.66%)27 ( 45%)tace ( % ) 17 ( 28.33%)16 ( 26.66%)17 ( 28.33%)femoral angiography ( % ) 10 ( 16.66%)4 ( 6.66%)3 ( 5%)coronary angiography ( % ) 10 ( 16.66%)13 ( 21.66%)14 ( 23.33%)blood level ( g / dl)hb13.32 3.2714.27 4.9814.25 4.77plt183.28 23.75176.78 31.25191 24.65tfca , tramsfemoral cerebral angiography ; tace , transcatheter
arterial chemoembolization ; hb , hemoglobin ; plt , platelet ;
sd , standard deviation ) .
tfca , tramsfemoral cerebral angiography ; tace , transcatheter
arterial chemoembolization ; hb , hemoglobin ; plt , platelet ;
sd , standard deviation groups a , b and c showed a mean times to hemostasis of 20.37 8.23 , 29.30 6.87 , and 28.9
7.25 min , respectively .
in other words , the time to hemostasis of the compression device
( group a ) was the shortest ( p < 0.05 ) .
the correlation coefficient between the time to
hemostasis and hemostasis method was 0.58 , indicating a correlation .
when the patients were classified according to gender , the time to hemostasis of males was
shorter than that of females . in group
a , the times to hemostasis of males and females were
29.83 5.17 and 28.67 2.38 min , respectively . in group
b , the times to hemostasis of
males and females were 18.67 2.81 and 21.12 1.89 min , respectively . in group c , the
times to hemostasis of males and females were 28.19 2.23 and 31.89 4.87 min ,
respectively .
there were no statistically significant differences according to gender ( p
> 0.05 ) . in regard to the hemostasis method according to age , the shortest times in group
a , b , and c was respectively , 22.29 5.82 min in those in their 50s , 16.50 9.19 min in
those in their 30s , and 24.40 6.27 min in those in their 70s , respectively .
no
statistically significant differences were observed between the three groups ( p > 0.05 ) .
the correlation coefficients between gender , generation , and hemostasis time were 0.232 and
0.125 , indicating no correlation ( table
3table 3 .
hemostasis time according to gender and generation ( unit : min)gendermean sdgroup a ( n=60)group b ( n=60)group c ( n=60)male29.83 5.1718.67 2.8128.19 2.23female28.67 2.3821.12 1.8931.89 4.87generationmean sd30s26.35 3.2516.50 9.1930.67 9.4040s32.43 16.5719.25 9.7830.23 8.9450s22.29 5.8218.14 5.9825.43 10.9460s28.00 9.4220.43 9.8135.83 18.2870s32.80 13.1021.83 7.4124.40 6.27sd , standard deviation ) .
sd , standard deviation in each hemostasis method , the correlation between the hemoglobin value , platelet value ,
and the time to hemostasis was examined .
the correlation coefficients for the association
between the time to hemostasis and the hemoglobin and platelet values in group a were 0.249
and 0.085 , respectively . in group
b , the correlation coefficients for the association
between the time to hemostasis and the hemoglobin and platelet values were 0.012 and
0.207 , respectively . in group c , the correlation coefficient for the association between
the time to hemostasis and the hemoglobin and platelet values were 0.200 and 0.206 ,
respectively . in each hemostasis method , although the hemoglobin or platelet values showed
slight individual differences , the overall value was significantly different ( table 4table 4 .
correlation between hemoglobin , platelet value , and the time to
hemostasishbpltgroup apearson correlation coefficient0.2490.085group bpearson correlation coefficient0.0120.207group cpearson correlation coefficient0.2000.206hb , hemoglobin ; plt , platelet ) .
hb , hemoglobin ; plt , platelet fifteen patients ( 25.0% ) in group a had complications ; 5 ( 8.33% ) showed a hematoma size
> 5 cm , and 10 ( 16.66% ) presented with pain .
no complications developed in group b. in
group c , 9 patients ( 15.0% ) had complications ; 2 ( 3.33% ) showed a hematoma size > 5 cm ,
and 7 ( 11.66% ) presented with pain .
therefore , complications developed at the highest rate
when hemostasis was carried out using a compression device only ( p < 0.05 ) .
with the development of interventional radiology , arterial puncture has played an important
role in the initiation of surgery .
although a range of approach routes can be applied
according to the type of surgery , it is generally performed via the femoral artery approach ,
and the common femoral artery has been shown to be the ideal puncture site .
the risk of
intra - abdominal or retroperitoneal bleeding is high if the proximal area of the inguinal
ligament , i.e. , the external iliac artery , is punctured , which might injure the inguinal
canal and intra - abdominal structures .
laceration of blood vessels , pseudoaneurysm ,
arteriovenous fistula , thrombosis , and excess bleeding can develop if the distal area of the
common femoral artery , i.e. , the deep femoral artery of the superficial femoral artery , is
punctured6 , 7 .
previously , at the time of hemostasis after surgery , manual compression that using the
hands as well as hemostasis using compression devices have been performed .
recently ,
patients have been able to walk within 12 h , and the discomfort of patients caused by
lengthy bed rest and a lengthy hospitalization period has been reduced using the arterial
closure device , angio - seal arterial closure device4 ,
5 . on the other hand ,
when compression
devices are used , infections in the inguinal area , acute arterial occlusion , and other large
and small complications have been reported8 .
nicolas reported that in the group that used a hemostasis device , a
pseudoaneurysm developed in 1 case ( 0.60%)9 .
in addition , among 156 cases , allergic reactions or inguinal
hematoma developed in 18 cases ( 11.5% ) .
the results
showed that side effects occurred 15 patients ( 25.0% ) using compression devices ; 5 patients
( 8.33% ) had a hematoma > 5 cm , and 10 patients ( 16.66% ) presented with pain .
when hemostasis was performed
with a compression device and the hands together , 9 patients ( 15.0% ) had complications , 2
patients ( 3.33% ) had a hematoma > 5 cm , and 7 patients ( 11.66% ) presented with pain . in
other words , the highest rate of complications developed when hemostasis was performed only
with compression devices .
in addition to side effects , the following correlations were compared : between the time to
hemostasis after angiography and gender ; the time to hemostasis of each generation and
hemoglobin value ; and platelet value and the time to hemostasis . in manual hemostasis , the
mean time to hemostasis was 20 min , which was the shortest .
on the other hand , the mean time
was 28 min when a compression device was used . when compressed with a compression device and
subsequently with the hands ,
other studies measured the period
from hemostasis to walking , not the time to hemostasis .
jeong et al . reported that walking
was possible 7.2 2.7 h after hemostasis with a compression device , and 17.3 4.3 h after
manual hemostasis10 .
showed
that the period to the initiation of walking was 7.9 h when hemostasis was carried out using
compression devices11 .
the results of the
present study were different from the above results , and this was attributed to the
difference in research methods . in the present study , the interval from angiography to
hemostasis was measured instead of the time to walking , which can explain the different
results .
in addition , there was no difference in the time to hemostasis according to gender
or generation , and the correlations of the hemoglobin value , platelet value , and the time to
homeostasis were not significant .
therefore , gender , age , hemoglobin value , and platelet
value have no significant involvement in hemostasis .
manual hemostasis can stop bleeding most accurately within a short time with a low
incidence of complications . on the other hand , in hemostasis using a compression device , it
is difficult to assess the level of pressure that compresses the blood vessels .
when a
fixation device is inserted , the compression bar is slanted if the bottom surface is not
hard .
in addition , if
patients are unconscious or unstable , the hemostasis points may move due to movement of the
patient , resulting in bleeding13 . on the
other hand , as in our hospital , if the number of personnel in the angiography room is small
( 1 radiologist , 2 nurses , 1 specialist clinician ) , unnecessary use of professional personnel
can be prevented by the application of a compression device .
in addition , the discomfort of
the person who performs hemostasis by manual compression when bleeding lasts for a long time
due to the use of anticoagulants can be resolved , and low - cost equipment can perform the
task of one person . therefore , it is anticipated that the turnover of patients can be
increased .
the incidence of complications and the time to hemostasis are increased when
hemostasis is carried out using a compression device .
on the other hand , the incidence of
side effects and the time to hemostasis are reduced when hemostasis is carried out using the
hands .
nevertheless , when compression devices are used , unnecessary use of professional
personnel can be prevented .
in addition , in hemostasis for a long time , the discomfort of
the person for whom hemostasis by manual compression is performed can be resolved .
overall ,
hemostasis performed mutually is safe and effective for patients according to their
condition . | [ purpose ] this study assessed the advantages and shortcomings of methods for hemostasis
in patients who had received angiography after femoral arterial puncture using manual ,
compression device , or a combination of manual compression and a compression device . in
addition , the success rates , complications , etc , were analyzed .
[ subjects and methods ] one
hundred and eighty patients who had undergone angiography after femoral arterial puncture
were divided into three groups according to the method of hemostasis . for group
a ,
immediately after angiography , an angio - seal device was placed in the puncture area and
compressed using a compression device . for group b , after angiography , the puncture area
was compressed with the hands directly . for group c ,
the puncture area was compressed
using a compression device for approximately 10 min , and the puncture area was then
compressed with the hands . in each group ,
the following correlations were analyzed : the
time to hemostasis after angiography and gender , the time to hemostasis of each generation
and the hemoglobin value , and platelet value and the time to hemostasis .
[ results ] the
results showed a similar time to hemostasis regardless of gender or generation .
the
correlation between the hemoglobin value , platelet value , and the time to hemostasis were
not significant .
group a showed the shortest mean time to hemostasis of the three groups
( 20.37 8.23 min ) .
no complications caused by the hemostasis method were detected in
group b. group a showed the highest incidence of complications caused by hemostasis .
[ conclusion ] overall , hemostasis performed mutually is safe and effective for patients
according to their condition . |
hypersexual disorder is primarily conceptualized as a disorder of sexual desire , with an impulsivity component .
it has symptoms befalling impulsive , compulsive , and addiction domains such as recurrent and intense sexual thoughts , urges , or behaviors , inability to control or stop the sexual behavior , and repetitively engaging in sexual behaviors disregarding associated risks .
selective serotonin reuptake inhibitors , antihormonal medications ( medroxyprogesterone acetate [ mpa ] , cyproterone acetate , gonadotropin - releasing hormone analogs ) , and other pharmacological agents ( naltrexone , topiramate ) have been shown to reduce sexual behavior in some patients ; however , substantial evidence of effectiveness is lacking .
transcranial magnetic stimulation ( tms ) has shown promise in management of various disorders involving impulsive - compulsive constructs such as substance addiction , obsessive - compulsive disorder ( ocd ) , and tourette 's syndrome .
considering hypersexual disorder on impulsive - compulsive spectrum , tms may be useful in management .
we report the case of a 29-year - old male who presented with complaints of intense and uncontrollable sexual urges for the past 15 years .
he would voyeur , frottage , read erotic literature , masturbate multiple times a day , visit sex workers , and feel relieved by getting indulged in the sexual acts .
he felt these sexual thoughts and arousals to be pleasurable , however , excessive along with distressing consequences .
there was gradual increase in frequency and severity of symptoms , which caused marital disharmony and impairments in daily functioning . out of despair , once he attempted to mutilate his genitalia through sharp weapon , though unsuccessfully .
the patient had earlier sought consultation from multiple health - care providers and received trials of multiple antidepressants ( fluoxetine , sertraline , clomipramine , alone as well as in combination ) for adequate dosages and duration .
attempts with antipsychotic augmentation , psychological interventions , and electroconvulsive therapy had also been tried without any significant benefit .
he had shown improvement on depot mpa but discontinued it due to intolerable side effects .
computed tomography scan of the brain and hormonal assays ( thyroid function tests , prolactin level , cortisol level , and androgen levels ) were normal .
he scored 109 on the 14-item sexual desire inventory ( sdi ) and 40 on 10-item sexual compulsivity scale ( scs ) ; the maximum attainable scores on both the scales .
psychological interventions such as scheduling of daily activities , relaxation exercises , and mindfulness meditation were done .
as there was no significant improvement over ongoing treatment , repetitive - tms ( rtms ) was planned for treatment augmentation .
the resting motor threshold ( rmt ) was determined , and 1 hz tms at 80% of rmt was administered over the supplementary motor area ( sma ) using the medistim ( ms-30 ) tms therapy system ( medicaid systems ) .
stimulation site was at junction of anterior two - fifth and posterior three - fifth ( according to the international 10/20 system of electrode placement ) of nasion - inion distance in midline .
each treatment session consisted of 14 trains of eighty pulses each with 5 seconds inter - train interval delivered over 19 minutes , giving a total of 1120 pulses / session .
he had a better control on his sexual thoughts and the frequency of masturbation decreased .
there was about 90% reduction in sdi and scs scores over 4-week time on rtms and concurrent pharmacotherapy .
the improvement persisted till 3 months follow - up during which frequency of sexual thoughts was significantly decreased and he resumed his work .
hypersexual disorder may have neurobiological underpinnings similar to other impulsive - compulsive spectrum disorders where dysfunctions of cortical - striatal - thalamic - cortical ( cstc ) circuitry have been demonstrated . in cstc loop , distinct cortical areas ( such as dorsolateral prefrontal cortex , sma , orbitofrontal cortex , medial prefrontal cortex , and anterior cingulate gyrus ) associated with different neurocognitive domains may be involved .
the sma has been shown to have widespread functional connections with other areas of the brain involved in cognitive processes and motor control .
moreover , altered sma connectivity has been demonstrated in patients suffering from ocd . studies further suggest reduced cortico - subcortical regulation and increased cortical excitability to play a part in repetitive behaviors .
rtms targeting this loop ( particularly to the sma ) has been shown to reduce compulsive behaviors in ocd patients , and similar underlying mechanism might be responsible for the beneficial effect in our patient .
approximately 5% patients may complain about some mild adverse events such as headache and nausea , following the session of tms .
patients with metallic implant ( aneurysmal clips , cochlear implants ) and pacemaker need caution as the magnetic field may alter their functioning or may cause tissue damage .
seizure is an extremely rare side effect with tms , may be seen in patients using medications that lower their seizure threshold .
this is , to the best of our knowledge , the rst report highlighting efficacy of rtms in hypersexual desire disorder . in our case ,
thus , tms could be considered as a treatment option in patients with hypersexual disorder .
| hypersexual disorder has phenomenological resemblance with impulsive - compulsive spectrum disorders .
inhibitory repetitive transcranial magnetic stimulation ( rtms ) over the supplementary motor area ( sma ) has been found to be effective in the management of impulsive - compulsive behaviors .
inhibitory rtms over sma may be helpful in hypersexual disorder .
we highlight here a case of hypersexual disorder ( excessive sexual drive ) who failed to respond adequately to the conventional pharmacological treatment and responded with rtms augmentation . |
metal - ceramic restorations have been successfully applied in restorative dentistry due to high fracture strength . however , achieving a natural translucency is more difficult with metal - ceramic restorations than all - ceramic restorations because metal substructures prevent light transmission in metal - ceramic restorations .
this has led to an increase in use of all - ceramic restorations . among all - ceramic restorations ,
however , high translucency of a restoration is not always an advantage , for instance in cases with discolored teeth , colored core materials and cast metal post and cores . in these clinical conditions , a restorative material with optimal masking ability of the underlying substructures
a method to evaluate the masking ability of restorative materials is to measure color differences in cie lab color system . in this color system ,
the l * , a * and b * color parameters and e refer to lightness , red - green value , yellow - blue value , and color difference , respectively , which can be measured by a spectrophotometer .
the e color difference is calculated using this formula :
e*ab=[(l*2l*1)2+(a*2a*1)2+(b*2b*1)2]1/2
which is the most commonly used formula for e .
this formula can detect even a small amount of color difference between two objects [ 9 , 10 ] .
as spectrophotometers can detect even the slightest amount of color difference not perceptible by the human eye , perceptual and clinically acceptable thresholds have been defined based on e values .
it has been reported that the clinically acceptable threshold is more than the perceptual threshold , because of optical conditions of oral environment .
if the e ( color difference ) between two objects is more than the perceptual threshold , a color mismatch will be detected by the human eye .
the perceptual threshold has been reported from e=1 to e=5.5 in different studies [ 1214 ] .
if a restorative material has an ideal masking ability , e will be equal to zero when placing the material on white and black substrates , namely that the material has a similar color on different substrates , and the substrates can not affect the color of the material . from a clinical point of view , if e of a material on different backgrounds is less than the threshold , it can thoroughly mask the background color .
several studies have surveyed the optical properties of different ceramic materials [ 8 , 1518 ] .
some studies have evaluated various factors affecting the final color of zirconia restorations including dental substrates [ 1922 ] , luting agents [ 21 , 23 ] , ceramic veneers [ 2426 ] , glaze , and firing process .
suputtamongkol et al , reported that the background color could affect the overall color of posterior zirconia restorations on a metal post and core or a prefabricated post and a composite core ; however , color changes did not exceed the perceptual threshold .
choi and razzoog assessed the masking ability of a zirconia ceramic ( zrc ) with and without the veneering porcelain and revealed that the zirconium oxide coping material alone had some degree of masking ability .
oh and kim disclosed that abutment shade , ceramic thickness and coping type affected the resulting color of zirconia restorations .
vichi et al , evaluated the effects of different substrates with different colors on the final color of all - ceramic ips - empress glass - ceramic restorations , and advised to take the color of substrate into consideration in cases with ceramic thickness of less than 1 mm .
masking ability of a zrc is related to its color coverage over underlying substructures including cement and dental substrates .
it may not be feasible to mask a substrate with cements , because different shades do not exist for all cements .
thus , it seems that the color masking ability of a zrc on different substrates may be an important factor affecting the esthetic results of zirconia - based restorations . on the other hand , posts and cores , which are widely applied in restorative dentistry to restore severely damaged teeth
the effects of these core materials ( as substrates ) on masking ability of zrcs ( as substructures in zirconia - based restorations ) have to be clearly determined . therefore ,
this in vitro study aimed to evaluate the effect of three different core materials including a nickel - chromium alloy ( nca ) , a non - precious gold alloy ( npga ) , and a zrc on masking ability of a zrc . the null hypothesis was that the zrc would mask the three aforementioned core materials with no significant difference .
the discs were placed over four substrates including a white ( w ) substrate ( as the control ) , nca , npga and zrc .
the procedure was conducted as follows :
specimen preparation : a computer - aided design / computer - aided manufacturing system ( coritec 250i , imes - icore gmbh , eiterfeld , germany ) milled zirconia blanks ( luminesse high strength / low translucency , 98 mm discs # 5113 ; talladium , valencia , ca , usa ) to fabricate zirconia discs .
the zirconia blanks had 37% translucency and were used to fabricate zirconia frameworks in zirconia - based restorations .
the discs had 0.5 mm thickness and 10 mm diameter [ 20 , 23 ] .
all the zirconia discs were sintered at 1520c for a 12-hour process in a sintering furnace ( isint ht , imes - icore gmbh , eiterfeld , germany ) . a digital micrometer ( 293 mdc - mx lite ; mitutoyo corporation , tokyo , japan ) with the accuracy of 0.002 mm
an adjustment / polishing kit ( bruxzir ; glidewell direct , irvine , ca , usa ) was used to reduce the thicknesses according to the afore - mentioned acceptable range . in case of lack of acceptable thickness
the zirconia discs were polished , cleaned in an ultrasonic bath ( elmasonic s-30 ; dentec , north shore , australia ) containing 98% ethanol for 15 minutes , and were finally dried .
the zirconia disc specimens were prepared as such , and had natural white color of zirconia ( fig .
1).substrate preparation : in order to fabricate the w substrate with the dimensions of 10 mm in diameter and 10 mm in height , a white teflon material ( ptfe , omnia plastica spa , busto arsizio , italy ) was milled .
then , two cylindrical acrylic resin ( duralay , reliance dental mgf co. , worth , il , usa ) patterns were formed according to the afore - mentioned dimensions .
the patterns were cast by a nca ( verabond v ; alba dent , fairfield , ca , usa ) and a npga ( alba dent , fairfield , ca , usa ) to fabricate nca and npga substrates , respectively . an adjusting / polishing kit ( np alloy adjustment kit ; shofu inc . , kyoto , japan )
was employed to polish the alloy substrates . in order to fabricate the zrc substrate ,
a cylindrical pattern was virtually designed by a software program ( solidworks 2015 , solidworks corp . ,
the same computer - aided design / computer - aided manufacturing system milled a zirconia blank ( luminesse high strength 98 mm discs # 5113 ; talladium , valencia , ca , usa ) to fabricate a zirconia substrate based on the above - mentioned virtual design .
the zirconia substrate was dipped in a2 shade color liquid ( dd bio zx2 monolithic zero lzdd ; dental direkt gmbh , spenge , germany ) for 10 seconds .
the zirconia substrate was sintered at 1520c for a 12-hour process in the same sintering furnace , and was then polished by the same polishing kit .
the four substrates of w , nca , npga , and zrc were prepared as such .
all the substrates were cleaned in the same ultrasonic bath containing 98% ethanol for 15 minutes ( fig .
2 ) color measurement : a spectrophotometer ( spectroshade micro , mht , verona , italy ) was employed for spectrometric measurements . a putty silicone material ( speedex ; coltene , altstatten , switzerland )
was adapted to the mouth piece of the spectrophotometer to match the conditions of spectrophotometry for all specimens and to prevent external lights .
the specimens were located at the center of this putty mold . before each measurement ,
the spectro - photometer was calibrated by the white and green calibration plates , respectively .
the discs were placed over the substrates with a water drop in - between to prevent the refraction of light .
each disc was placed on each of the substrates , and the color measurements were made .
all the color measurements were made at the center of specimens marked by a pen on the monitor screen of spectrophotometer .
the color parameters of l * , a * , and b * were recorded for each specimen .
additionally , e values were calculated to determine the e of disc on the substrates . in order to compare the color of specimens on the nca , npga , and
zrc substrates with their color on the w substrate , the e values were measured in three situations including : w - nca , w - npga , and w - zrc .
the e
w - nca
e
w - npga
, and e
w - zrc
values were calculated using this formula :
e*ab=[(l*2l*1)2+(a*2a*1)2+(b*2b*1)2]1/2
specimen preparation : a computer - aided design / computer - aided manufacturing system ( coritec 250i , imes - icore gmbh , eiterfeld , germany ) milled zirconia blanks ( luminesse high strength / low translucency , 98 mm discs # 5113 ; talladium , valencia , ca , usa ) to fabricate zirconia discs .
the zirconia blanks had 37% translucency and were used to fabricate zirconia frameworks in zirconia - based restorations .
the discs had 0.5 mm thickness and 10 mm diameter [ 20 , 23 ] .
all the zirconia discs were sintered at 1520c for a 12-hour process in a sintering furnace ( isint ht , imes - icore gmbh , eiterfeld , germany ) . a digital micrometer ( 293 mdc - mx lite ; mitutoyo corporation , tokyo , japan ) with the accuracy of 0.002 mm
an adjustment / polishing kit ( bruxzir ; glidewell direct , irvine , ca , usa ) was used to reduce the thicknesses according to the afore - mentioned acceptable range . in case of lack of acceptable thickness
the zirconia discs were polished , cleaned in an ultrasonic bath ( elmasonic s-30 ; dentec , north shore , australia ) containing 98% ethanol for 15 minutes , and were finally dried .
the zirconia disc specimens were prepared as such , and had natural white color of zirconia ( fig .
substrate preparation : in order to fabricate the w substrate with the dimensions of 10 mm in diameter and 10 mm in height , a white teflon material ( ptfe , omnia plastica spa , busto arsizio , italy ) was milled .
then , two cylindrical acrylic resin ( duralay , reliance dental mgf co. , worth , il , usa ) patterns were formed according to the afore - mentioned dimensions .
the patterns were cast by a nca ( verabond v ; alba dent , fairfield , ca , usa ) and a npga ( alba dent , fairfield , ca , usa ) to fabricate nca and npga substrates , respectively . an adjusting / polishing kit ( np alloy adjustment kit ; shofu inc . ,
kyoto , japan ) was employed to polish the alloy substrates . in order to fabricate the zrc substrate ,
a cylindrical pattern was virtually designed by a software program ( solidworks 2015 , solidworks corp . ,
the same computer - aided design / computer - aided manufacturing system milled a zirconia blank ( luminesse high strength 98 mm discs # 5113 ; talladium , valencia , ca , usa ) to fabricate a zirconia substrate based on the above - mentioned virtual design .
the zirconia substrate was dipped in a2 shade color liquid ( dd bio zx2 monolithic zero lzdd ; dental direkt gmbh , spenge , germany ) for 10 seconds .
the zirconia substrate was sintered at 1520c for a 12-hour process in the same sintering furnace , and was then polished by the same polishing kit .
the four substrates of w , nca , npga , and zrc were prepared as such .
all the substrates were cleaned in the same ultrasonic bath containing 98% ethanol for 15 minutes ( fig .
2 ) color measurement : a spectrophotometer ( spectroshade micro , mht , verona , italy ) was employed for spectrometric measurements . a putty silicone material ( speedex ; coltene , altstatten , switzerland )
was adapted to the mouth piece of the spectrophotometer to match the conditions of spectrophotometry for all specimens and to prevent external lights .
the specimens were located at the center of this putty mold . before each measurement ,
the spectro - photometer was calibrated by the white and green calibration plates , respectively .
the discs were placed over the substrates with a water drop in - between to prevent the refraction of light .
each disc was placed on each of the substrates , and the color measurements were made .
all the color measurements were made at the center of specimens marked by a pen on the monitor screen of spectrophotometer .
the color parameters of l * , a * , and b * were recorded for each specimen .
additionally , e values were calculated to determine the e of disc on the substrates . in order to compare the color of specimens on the nca , npga , and
zrc substrates with their color on the w substrate , the e values were measured in three situations including : w - nca , w - npga , and w - zrc .
the e
w - nca
e
w - npga
, and e
w - zrc
values were calculated using this formula :
e*ab=[(l*2l*1)2+(a*2a*1)2+(b*2b*1)2]1/2
zirconia disc specimens tested substrates ( from left to right : zirconia ceramic , non - precious gold alloy , nickel - chromium alloy and white substrate ) the perceptual threshold of e=2.6 was considered in this study [ 1214 ] .
normal distribution of the data was accepted in all groups by the kolmogorov - smirnov test ( p>0.05 ) .
the values of l * , a*and b * for each disc in npga , nca and zrc groups were subtracted from l*white , a*white and b*white values , which were the corresponding values for w substrate . in order to compare the standard l * , a * , b * ( from which , the values of w substrate were subtracted ) and e values among the groups , randomized block anova was employed .
stata software ( statacorp lp , lakeway , tx , usa ) compared the e values with the predetermined perceptual threshold of e=2.6 using one - sample t - test .
the results were explained according to the measured variables of l * , a * , b * , and e in four sections .
l * parameter ( lightness ) : the mean and standard deviation of the l * values for the w , nca , npga and zrc groups were 88.351.46 , 78.241.31 , 78.981.26 , and 82.161.16 units , respectively ( table 1 , fig .
3 ) . statistical analysis showed a significant difference among the groups in this regard ( p<0.0001 ) .
pairwise comparisons of the groups using bonferroni test revealed significant differences between the nca and zrc ( p<0.0001 ) , and npga and zrc ( p<0.0001 ) .
the color parameter values in the four groups of white substrate ( w ) , nickel - chromium alloy ( nca ) , non - precious gold alloy ( npga ) and zirconia ceramic ( zrc ) the mean l * values of the groups a * parameter ( red - green value ) : the mean and standard deviation of the a * values for the w , nca , npga and zrc groups were 0.400.42 , 0.040.52 , 0.600.42 , and 1.520.38 units , respectively ( table 1 , fig .
pairwise comparisons of the groups using bonferroni test revealed significant differences between nca and npga ( p<0.0001 ) , nca and zrc ( p<0.0001 ) and npga and zrc ( p<0.0001 ) .
the a * values increased in all the groups compared to the control . the increase in the a
the mean a * values of the groups b * parameter ( yellow - blue value ) : the mean and standard deviation of the b * values for the w , nca , npga , and zrc groups were 3.380.36 , 1.921.01 , 3.860.49 , and 4.880.57 units , respectively ( table 1 , fig .
pairwise comparisons of the groups using bonferroni test showed significant differences between nca and npga ( p<0.0001 ) , nca and zrc ( p<0.0001 ) , and npga and zrc ( p<0.001 ) .
zrc had the highest b * value , and nca had the lowest b * value among the groups .
the mean b * values of the groups e ( color difference ) : the mean and standard deviation of the e values for the nca , npga and zrc groups were 10.262.43 , 9.451.74 , and 6.701.91 units , respectively ( table 1 , fig .
pairwise comparisons of the groups using bonferroni test showed significant differences between nca and zrc ( p<0.0001 ) , and npga and zrc ( p=0.001 ) .
the difference between nca and npga was not statistically significant ( p=0.65 ) . in order to compare the e values of the groups with the predetermined perceptual threshold of e=2.6 ,
the null hypothesis of e 2.6 was rejected for all the groups ( p<0.0001 ) .
the present study evaluated the color parameters of l * , a * , b * , and e for zirconia disc specimens on four different substrates including w , nca , npga and zrc .
statistical analysis indicated significant differences among the groups in the l * , a * , b * and e values .
the examined zrc on the tested substrates showed perceptible color change namely that the examined zrc could not thoroughly mask the tested substrates .
the l * ( lightness ) values decreased in all the groups compared with the control .
the change in l * value shows the impact of the substrates on the zirconia specimens .
this can be explained by the optical properties of zrc , which is a semi - translucent material .
according to the results , metal core materials such as ncas and npgas can decrease the lightness of zrc more than a zirconia core material
the a * ( red - green ) values increased in all the groups compared to the control .
a reason for this may be the natural a * value of the zrc as a substrate .
the tested zirconia substrate ( a2 shade ) positively shifted the a * value towards red .
the b * ( yellow - blue ) values changed in the groups depending on the substrates . the nickel - chromium substrate decreased the b * value while the non - precious gold and zirconia substrates increased the b * value compared to the control .
this may be due to the yellow color tendency of a2 shade zirconia substrate and npga , which impact on the color of zrc and shift it towards yellow . on the contrary , nca shifted the color of zrc towards blue , and negatively affected the b * value .
the e values of all groups were more than the predetermined perceptual threshold of e=2.6 .
assessment of the l * , a * and b * values indicated their changes in the substrate groups . thus , color changes were derived from all three color parameters .
the l * , a * , and b * values manifested significant differences between the substrate groups .
this demonstrated that the quality of the color change was different depending on the substrate .
the e values manifested no significant difference between the metal substrates ; however , significant differences existed between the zirconia substrate and the metal substrates , and the least color change belonged to the zirconia substrate .
this demonstrated that the quantity of the color change was different depending on the substrate as well .
hence , both quality and quantity of the color of zrc were altered by the substrates .
the used metal substrates did not differ in terms of the quantity of color change , and both affected the quantity of the color change more than the zirconia substrate .
suputtamongkol et al , reported that the color of an underlying substructure could affect the overall color of posterior zirconia - based restorations on a metal post and core or a prefabricated post and a composite core , ranging from e = 1.2 to 3.1 .
additionally , slight color changes of zirconia crowns were detected by measuring the e . although some differences exist between the afore - mentioned study and the current research such as zrc brands , thicknesses of ceramics , veneered versus non - veneered zrcs , hypothesized perceptual thresholds and substrate types , both studies showed that zrc could not thoroughly mask the underlying materials .
oh and kim in an in vitro study of color masking ability assessed the effects of abutment shade , ceramic thickness and coping type on the final color of zirconia restorations .
the abutments were fabricated of gold alloy , base metal ( nickel - chromium ) alloy , and four different shades of composite resins . in their study , the average e value of lava specimens between the a2 shade composite resin and gold alloy abutments was higher than that between the a2 shade composite resin and other abutments , and was close to e=5.5 .
a similar result was obtained in the current study , although the substrates and zrcs used in the two studies were different .
according to the study by oh and kim , gold alloy substrate yielded the highest e among the tested substrates ; however , the npga and the nca yielded close e values in the current study .
this dissimilarity in the results may be caused by the color difference of the precious gold alloy used by oh and kim and the npga used in the current study .
choi and razzoog evaluated the masking ability of zrc with and without a veneering porcelain . in their study , color differences caused by zrc and the veneering porcelain were compared with substrates alone .
they concluded that the non - veneered zrc had some degree of masking ability over different tested substrates ( white , black , gray , and a3 shade tooth - colored substrates ) .
however , the current study compared substrate - induced color differences with a zrc over w substrate and concluded that the tested zrc could not mask the examined substrates .
choi and razzoog measured the e values between the substrate alone ( as control ) and the zrc over the substrate , while the current study measured the e values between the zrc over w substrate ( as control ) and zrc over the tested substrates .
based on the results of our study , the three core materials including nca , npga and zrc can change the color of tested zrc .
the color of zrc may be closer to the final color of a restoration than the metal cores .
therefore , it is esthetically advised to preferably choose a zrc post and core instead of nca or npga post and cores in zirconia - based restorations and to reduce the core material - induced color change by further core reduction , applying sufficient thickness of the veneering porcelain , and use of proper luting agents in zirconia - based restorations .
it should be noted that given that the physical and mechanical properties of zirconia post and core are confirmed in further studies , zirconia post and core should be clinically recommended .
this needs future investigations . considering the optical properties of zrc and the thickness of zirconia sub - structures , which is approximately 0.5 mm in a normal case
, light transmission through the zirconia structure can be expected in zirconia - based restorations .
the present study evaluated the effects of three core materials in this respect . on the other hand ,
the zirconia core overlaying materials such as porcelain veneers and glaze may influence the final color of zirconia - based restorations , which were not assessed in this study .
therefore , evaluation of the effect of other factors in this respect is recommended in future studies .
the present study had some limitations such as using a specific brand of zrc , an uncolored zrc , and a specific brand of composite resin .
within the limitations of this study , it was concluded that the tested zrc could not thoroughly mask the three core materials of nca , npga , and zrc . | objectives : masking ability of a restorative material plays a role in hiding colored substructures ; however , the masking ability of zirconia ceramic ( zrc ) has not yet been clearly understood in zirconia - based restorations .
this study evaluated the effect of three different core materials on masking ability of a zrc.materials and methods : ten zirconia disc samples , 0.5 mm in thickness and 10 mm in diameter , were fabricated .
a white ( w ) substrate ( control ) and three substrates of nickel - chromium alloy ( nca ) , non - precious gold alloy ( npga ) , and zrc were prepared .
the zirconia discs were placed on the four types of substrates for spectrophotometry .
the l * , a * , and b * values of the specimens were measured by a spectrophotometer and color change ( e ) values were calculated to determine color differences between the test and control groups and were then compared with the perceptual threshold .
randomized block anova and bonferroni test analyzed the data .
a significance level of 0.05 was considered.results:the mean and standard deviation values of e for nca , npga , and zrc groups were 10.262.43 , 9.451.74 , and 6.701.91 units , respectively .
significant differences were found in the e values between zrc and the other two experimental groups ( nca and npga ; p<0.0001 and p=0.001 , respectively ) . the e values for the groups were more than the predetermined perceptual threshold.conclusions:within the limitations of this study , it was concluded that the tested zrc could not well mask the examined core materials . |
traditionally , esophagectomy has been performed by 1 of 3 routes : a thoracoabdominal approach , a 3-stage procedure also including an anastomosis in the neck , or a transhiatal approach .
the transhiatal approach was initially described by denk in 1913 , but was later popularized by orringer .
however , all 3 methods have an acknowledged high intraoperative and postoperative morbidity , as well as mortality rates in published series of up to 23% .
minimally invasive surgery has revolutionized many areas of surgery , with laparoscopic cholecystectomy and fundoplication accepted as the gold standards in their areas .
but with the potential to reduce trauma , it is believed that by using these methods it should be possible to reduce the high morbidity and mortality associated with these procedures . also widely held concerns are associated with laparoscopic oncologic surgery , because of the possibility of missed lesions , inadequate staging , compromised margins , inadequate lymph node retrieval and tumor dissemination including port - site metastases .
particular to esophagectomy , concerns also exist that decreased tactile control may possibly increase the risk of injuring adjacent and vital structures in the chest , particularly for tumors above the tracheal bifurcation .
however , this procedure should not only be aimed at cancer surgery , it also has potential benefits and attractions for other areas of treatment including patients with high - grade dysplasia in barrett 's esophagus , patients whose esophageal strictures are resistant to other treatment , and patients with end - stage achalasia .
the literature shows little agreement for the best application of minimal access techniques to esophagectomy . the most popular method described in the literature is a thoracic esophagectomy coupled with gastric mobilization via laparotomy and a cervical anastomosis .
various other groups have used differing combinations of laparoscopic , thoracoscopic , and open techniques .
the use of hand - assist devices has also been noted . a large series of minimally invasive esophagectomies using primarily thoracoscopic mobilization has observed a 1.4% mortality rate in 222 consecutive patients .
what can be inferred from much of the work with the thoracoscope is that this requires the use of prolonged single - lung ventilation ( much in excess of the open methods ) and mediastinal trauma remains substantial .
this has done little to reduce the morbidity and mortality from this procedure in many series .
two groups in germany have also described the use of a novel mediastinoscope , though its use has not become widespread , and its use is limited to tumors that are not bulky .
the method that is used in our district general hospital is that of a laparoscopic transhiatal esophagectomy .
two groups have reported in the literature their results using this technique , with a long operating time , a high rate of vocal cord palsy , high leakage rates , and a mortality rate of up to 13% .
it would appear from these reports and from much of the other work that these methods offer little advantage over traditional methods .
the aim of this study was to compare the results of our experience in a small district general hospital with published data , the hypothesis being that surgery in such a setting is comparable to the results in larger centers .
the patient is placed supine on the table with an operative setup similar to that of a laparoscopic nissen fundoplication .
the port placement involves a 10-mm port in the epigastrium with 12-mm working ports on either side .
a 5-mm port is placed for retraction in the anterior axillary line below the left coastal margin , and a nathanson liver retractor is placed to aid exposure of the hiatus .
the technique is similar to that described by swanstrom ; however , we have not found it necessary to use 45-mm instruments .
the operation proceeds much as the open procedure with the mobilization of the stomach on the right gastroepiploic arcade .
the operation differs from the open procedure in that the transhiatal mobilization is carried to the level of the bronchial vessels under direct vision .
a gastric tube is created with an endo - gia staple gun , which is then oversewn with absorbable suture for delivery of the specimen to the neck .
this is a running suture and was introduced after case 6 . during this procedure ,
the dissection can normally be achieved using standard 30-mm instruments and one series of port placements . occasionally , because of the patients habitus modifications to these placements have to be entertained .
this is achieved through an incision along the anterior border of the sternomastoid , with division of the omohyoid muscle and exposure and mobilization of the esophagus away from the trachea and prevertebral fascia , avoiding the recurrent laryngeal nerve . the specimen is then delivered to the neck by a combination of gentle traction from above and gentle manipulation from below with the laparoscopic instruments . in the neck ,
the specimen undergoes resection , and anastomosis is performed using an endo gia stapling device .
occasionally , a left subcoastal incision is required to deliver a bulky specimen if there is difficulty in passing through the hiatal orifice .
the size of the wound is dependent to a certain extent on patient habitus and specimen size .
if such an incision was used then this was also used to place a jejunostomy for enteral feeding .
the patient is placed supine on the table with an operative setup similar to that of a laparoscopic nissen fundoplication .
the port placement involves a 10-mm port in the epigastrium with 12-mm working ports on either side .
a 5-mm port is placed for retraction in the anterior axillary line below the left coastal margin , and a nathanson liver retractor is placed to aid exposure of the hiatus .
the technique is similar to that described by swanstrom ; however , we have not found it necessary to use 45-mm instruments .
the operation proceeds much as the open procedure with the mobilization of the stomach on the right gastroepiploic arcade .
the operation differs from the open procedure in that the transhiatal mobilization is carried to the level of the bronchial vessels under direct vision .
a gastric tube is created with an endo - gia staple gun , which is then oversewn with absorbable suture for delivery of the specimen to the neck .
this is a running suture and was introduced after case 6 . during this procedure ,
the dissection can normally be achieved using standard 30-mm instruments and one series of port placements . occasionally , because of the patients habitus modifications to these placements have to be entertained .
this is achieved through an incision along the anterior border of the sternomastoid , with division of the omohyoid muscle and exposure and mobilization of the esophagus away from the trachea and prevertebral fascia , avoiding the recurrent laryngeal nerve . the specimen is then delivered to the neck by a combination of gentle traction from above and gentle manipulation from below with the laparoscopic instruments . in the neck ,
the specimen undergoes resection , and anastomosis is performed using an endo gia stapling device .
occasionally , a left subcoastal incision is required to deliver a bulky specimen if there is difficulty in passing through the hiatal orifice .
the size of the wound is dependent to a certain extent on patient habitus and specimen size .
if such an incision was used then this was also used to place a jejunostomy for enteral feeding .
twenty - nine patients were referred for consideration of laparoscopic transhiatal esophagectomy after radiological assessment as being possibly suitable for resection . however , 9 patients were found at diagnostic laparoscopy to have advanced disease and therefore were discharged the same day . of the 20 patients operated on , 17 underwent a laparoscopic transhiatal resection with cervical anastomosis .
one had a laparoscopic transhiatal resection of a tumor , which histologically was a gastrointestinal stromal tumor .
all statistical figures given ( unless specified otherwise ) are the median followed by the inter - quartile ranges .
the patients ' ages ranged from 34 to 78 with a median age of 63 .
pathologies included 2 squamous cell carcinomas , 1 gastrointestinal stromal tumor , 6 high - grade dysplasias ( 2 contained early invasive carcinoma ) , and 11 adenocarcinomas .
the median time of the procedure was 415 minutes ( range , 320 to 480 ) ( figure 1 ) ; this is the total operative time taken including any surgical breaks .
it should be noted that from patient 7 the oversewing of the gastric tube added some 40 minutes to 60 minutes to the time of the procedure .
the total blood loss as recorded by the nursing staff was 300 ml ( range , 200 to 350 ) .
the total operative time ( including breaks ) listed as length of operation and the total blood loss as recorded in the notes for patients listed in order of their procedure .
the figures on the y - axis are minutes for time and ml of blood for blood loss .
this was in relation to the identification and transection of the left gastric artery ( patient 10 ) .
initially , thoracoscopy was attempted ; however , because of previous tuberculosis apical adhesions were present , and the lung would not deflate , precluding access and an endoscopic procedure ( patient 12 ) .
this patient also then had a prolonged stay in the critical care complex but was discharged from the unit ; unfortunately , on day 33 the patient suffered an extensive cerebrovascular accident and died on day 34 .
the incision was small and of a size sufficient to deliver the specimen from the abdominal cavity .
the reasons for nondelivery of the specimen varied , but included bulky tumors and in one case a single band of attachment in the mediastinum , which could not be identified .
this was either via a nasogastric tube placed at the time of surgery or via a jejunal tube that was tunneled at the time of surgery .
this enteral feeding continued until full oral feeding was possible and thus lasted for a median of 8 days ( range , 7 to 14 ) .
a contrast swallow was performed at a median of 7 days ( range , 6 to 8) .
three of these studies showed leaks ( 15% ) at the level of the anastomosis : 2 of these were on the initial study , 1 was demonstrated on a repeat study .
this patient also experienced an upper gastrointestinal bleed ( patient 15 ) ( see postoperative complications ) .
the leaks were managed conservatively with enteral feeding continued via the nasogastic or jejunal route .
figure 2 displays the length of postoperative ventilation and days spent in the intensive care unit .
one laparotomy for omental bleeding was necessary on the first postoperative day ( patient 14 ) .
one patient developed bilateral pleural effusions that clinically produced dyspnea . these required drainage , but settled rapidly with this intervention .
the total time spent on the ventilator and on the itu stay and time spent on the ventilator as measured in days with the sequence of patients listed on the x - axis .
these all settled rapidly on conservative management , none requiring intervention . one postoperative death ( patient 12 ) occurred .
this was a patient converted to an open procedure , and he died of a cerebrovascular accident on day 34 postoperatively .
one patient had a sudden and massive hemetemesis from a duodenal ulcer that led to a cardiorespiratory arrest ( patient 15 ) .
this was successfully managed medically with no requirement for further surgery , and the patient was discharged home on day 65 postoperatively , with no long - term adverse sequeale .
the median length of in - patient hospital stay was 17 days ( range , 10 to 28 ) .
all patient specimens when examined showed clear resection margins both proximally and distally as well as circumferentially .
a median number of 5 ( range , 2 to 6 ) lymph nodes were found by histological examination ; however , this was a retrospective study , and the completeness of the examination for these ca n't be commented upon .
four of the patients were found to have evidence of metastatic spread to the nodes at the time of pathological staging . on follow - up , most patients have required anastomotic dilatation .
all have settled with anastomotic dilatation performed with sedation in an outpatient endoscopy unit setting .
three deaths occurred on follow - up ( at a mean 11 months after surgery ) from recurrent disease .
all of these have been in patients who were node positive at the time of surgery .
the patients ' ages ranged from 34 to 78 with a median age of 63 .
pathologies included 2 squamous cell carcinomas , 1 gastrointestinal stromal tumor , 6 high - grade dysplasias ( 2 contained early invasive carcinoma ) , and 11 adenocarcinomas .
the median time of the procedure was 415 minutes ( range , 320 to 480 ) ( figure 1 ) ; this is the total operative time taken including any surgical breaks .
it should be noted that from patient 7 the oversewing of the gastric tube added some 40 minutes to 60 minutes to the time of the procedure .
the total blood loss as recorded by the nursing staff was 300 ml ( range , 200 to 350 ) .
the total operative time ( including breaks ) listed as length of operation and the total blood loss as recorded in the notes for patients listed in order of their procedure .
the figures on the y - axis are minutes for time and ml of blood for blood loss .
this was in relation to the identification and transection of the left gastric artery ( patient 10 ) .
initially , thoracoscopy was attempted ; however , because of previous tuberculosis apical adhesions were present , and the lung would not deflate , precluding access and an endoscopic procedure ( patient 12 ) .
this patient also then had a prolonged stay in the critical care complex but was discharged from the unit ; unfortunately , on day 33 the patient suffered an extensive cerebrovascular accident and died on day 34 .
the incision was small and of a size sufficient to deliver the specimen from the abdominal cavity .
the reasons for nondelivery of the specimen varied , but included bulky tumors and in one case a single band of attachment in the mediastinum , which could not be identified .
this was either via a nasogastric tube placed at the time of surgery or via a jejunal tube that was tunneled at the time of surgery .
this enteral feeding continued until full oral feeding was possible and thus lasted for a median of 8 days ( range , 7 to 14 ) .
a contrast swallow was performed at a median of 7 days ( range , 6 to 8) .
three of these studies showed leaks ( 15% ) at the level of the anastomosis : 2 of these were on the initial study , 1 was demonstrated on a repeat study .
this patient also experienced an upper gastrointestinal bleed ( patient 15 ) ( see postoperative complications ) .
the leaks were managed conservatively with enteral feeding continued via the nasogastic or jejunal route .
figure 2 displays the length of postoperative ventilation and days spent in the intensive care unit .
one laparotomy for omental bleeding was necessary on the first postoperative day ( patient 14 ) .
one patient developed bilateral pleural effusions that clinically produced dyspnea . these required drainage , but settled rapidly with this intervention .
the total time spent on the ventilator and on the itu stay and time spent on the ventilator as measured in days with the sequence of patients listed on the x - axis .
these all settled rapidly on conservative management , none requiring intervention . one postoperative death ( patient 12 ) occurred .
this was a patient converted to an open procedure , and he died of a cerebrovascular accident on day 34 postoperatively .
one patient had a sudden and massive hemetemesis from a duodenal ulcer that led to a cardiorespiratory arrest ( patient 15 ) .
this was successfully managed medically with no requirement for further surgery , and the patient was discharged home on day 65 postoperatively , with no long - term adverse sequeale .
the median length of in - patient hospital stay was 17 days ( range , 10 to 28 ) .
all patient specimens when examined showed clear resection margins both proximally and distally as well as circumferentially .
a median number of 5 ( range , 2 to 6 ) lymph nodes were found by histological examination ; however , this was a retrospective study , and the completeness of the examination for these ca n't be commented upon .
four of the patients were found to have evidence of metastatic spread to the nodes at the time of pathological staging .
all have settled with anastomotic dilatation performed with sedation in an outpatient endoscopy unit setting .
three deaths occurred on follow - up ( at a mean 11 months after surgery ) from recurrent disease .
all of these have been in patients who were node positive at the time of surgery .
over a thousand patients have been reported in the literature as having undergone a laparoscopic or laparoscopically assisted esophagectomy .
the results regarding morbidity and mortality are mixed and vary between the centers and methodologies .
the results achieved in our series are certainly comparable for mortality and morbidity with those seen in previous series for transhiatal esophagectomy
( table 1 ) .
a comparisonbetween current series and previous reported series of total laparoscopic transhiatal esophagectomy total operative time including any breaks taken by the surgeon .
the advantages that magnified dissection especially of the gastroesophageal junction and above must not be underestimated .
this is especially so when one considers the open transhiatal approach with dissection of the mediastinum achieved by blunt dissection by the surgeons ' hand .
also the pressure of the pneumoperitoneum aids the dissection of the esophagus and ensures a wide dissection .
the laparoscopic approach also holds the advantage in those cases that are inoperable especially where radiological evidence has been equivocal .
these patients are discharged the following day by avoiding a full - blown staging laparotomy .
the definition of a learning curve for laparoscopic esophagectomy has been attempted by a single surgeon . however , a number of considerations exist .
what are surgeons ' previous laparoscopic and open esophagectomy experiences ? what is a good parameter to measure the learning curve ?
indeed time is a poor indicator of quality , and there will be variation in the patient and possibly there will be evolution of the technique . in this series , failure of the gastric tube
was found on delivery to the neck ; ie , this was a failure of the stapling device .
this resulted in the modification of the technique to include an oversew of the staple line , adding some appreciable time to the length of the procedure for patient 7 . in terms of pathology
, it would appear that satisfactory margins of clearance have been obtained in those patients with a cancer .
a transhiatal approach also has the advantage of ensuring in those patients with high - grade dysplasia in a barrett 's esophagus that as much of the esophageal mucosa is removed as possible , in theory lowering the risk of malignant change .
the method would also appear to provide adequate staging of lymphatic spread with a median of 5 nodes removed .
however , because this was a retrospective study , the completeness of the pathologist 's examination of the specimen for nodes can not be addressed . within the confines of this paper
, we will not discuss either the advantages or disadvantages of extended lymphadenectomy for esophageal cancer because this is beyond the scope of this work , but if lymph node involvement is present then systemic disease is obviously present .
a recent large , randomized , controlled trial examining open transhiatal and transthoracic surgery failed to show a significant difference in survival between the 2 methods . compared with time reported in other results , the time to discharge is slow ; however , further work must be undertaken at ensuring an earlier discharge of the patient including the possibility of earlier introduction of oral intake . as a part of this contrast
, swallows are now being performed on day 2 so that fluids could potentially be introduced at an earlier stage .
the earlier the return to oral nutrition in a group where dysphagia and consequent malignant malnourishment have had a profound effect should not be underestimated .
this early study however will not exclude a delayed leak , but this possibility must be explored .
long - term follow - up must continue because this study considered only the early morbidity and mortality .
this will be essential if this procedure is to be considered from an oncological success .
comparison with open data should also occur because this article reports the experience of a single surgeon , allowing for a reasonable comparison between open and laparoscopic techniques .
what has not been considered in this study is patient acceptability , preference , and return to normal function compared with these things in open traditional surgery .
empirically , with earlier mobilization , lower analgesic requirements , and earlier return to oral feeding , one would expect minimal access techniques to have advantages and enhanced patient satisfaction .
we conclude that laparoscopic transhiatal resection of the esophagus in this series was both safe and feasible in a district general hospital with results similar to those in centers of excellence
. the technique should be more widely offered to patient as an acceptable and safe option . | objective : esophagectomy is an operation with high morbidity and mortality . its adoption as a minimally invasive operation worldwide has been slow , but the potential benefits of reducing the trauma of surgery need to be considered .
our 30-month experience with transhiatal esophagectomy in a district general hospital is presented herein.methods:patients were considered for surgery after radiological staging had excluded inoperable disease .
laparoscopic staging was initially performed .
patients with tumors of the esophagus and high - grade dysplasia in a barrett 's esophagus were included.results:twenty-nine patients were referred for consideration for resectional surgery .
nine underwent outpatient laparoscopy only .
twenty patients ( age range , 34 to 78 , 15 males:5 females ) underwent resectional surgery .
seventeen transhiatal resections were completed , 2 were converted to open procedures , and 1 transhiatal resection of a benign tumor was performed .
median time of surgery was 415 minutes ( range , 320 to 480 ) and blood loss was 300 ml ( range , 200 to 350 ) .
the median length of postoperative ventilation and critical care stay were 1 ( range , 1 to 4 ) and 4 ( range , 2 to 8) days .
median duration of hospitalization was 17 days ( range , 10 to 28 ) .
thirty - day mortality was 0 ; 1 patient who was converted to an open procedure died after a cerebrovascular event on day 34.conclusion:a zero mortality rate for laparoscopic resection and a low - morbidity rate compare well with morbidity and mortality in reported series using this method and open surgery .
laparoscopic transhiatal esophagectomy is an advanced , complex procedure that can be performed safely in a district general hospital setting . |
water is also important for protein folding and stability , and it is also known to actively participate in many catalytic processes in the cell . as such
protein and protein ligand interaction studies with respect to rational drug design.(1 ) however , despite the wealth of structural information , the precise role of water molecules in mediating receptor ligand interactions remains unclear.(2 ) in the context of drug design , one key problem is knowing whether a certain water molecule will be readily displaceable by functional groups designed to replace it . this issue has been the focus of recent computational studies . while pure molecular dynamics studies focused on identifying and characterizing the interactions between the protein , ligand , and conserved water molecules,(6 ) free energy calculations were used to further elucidate the functions of these water molecules and probe their apparent stabilizing role in the protein binding site .
a measure of the free energy is ultimately what is required in order to assess the stability of water molecules within binding sites .
however , obtaining sufficient accuracy of these calculations , especially for charged systems ( which encompasses most biological systems ) , is particularly challenging and an area of intense investigation.(10 ) one factor in these calculations is the underlying simplicity of the force - field which may or may not account for interactions at the necessary level required . even with these simplified models ,
the calculations are still time - consuming enough to be prohibitive at the level of virtual screening .
nevertheless they do form the underlying physical basis of many scoring functions employed in virtual high - throughput screening methods , and consequently , it is of great interest to improve them as much as possible .
many binding pockets have a complex network of water molecules and in some instances this has already been exploited to give increased drug potency , for example , in the case of hiv-1 protease where cyclic urea derivatives were designed to displace a conserved water molecule.(11 ) related to the problem of displaceable water molecules is the concept that water molecules can be considered as part of the drug rather than part of the protein .
this can lead to the situation where similar compounds that might be expected to adopt the same binding pose on the basis of their chemical structure , actually adopt different poses within the binding pocket .
a good example of this can be found in structures of the ionotropic glutamate receptors which are an important set of potential drug targets within the central nervous system .
the ionotropic glutamate receptors ( iglurs ) can be classified , both in terms of sequence similarity and pharmacology , into three major subclasses : ( s)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl ) propionic acid ( ampa ; glua14 ) , n - methyl - d - aspartic acid ( nmda ; glun13 ) ) and kainic acid ( gluk15 )
receptors.(12 ) these receptors are activated by glutamate , the major excitatory neurotransmitter in the vertebrate central nervous system ( cns).(13 ) iglurs play key roles in various physiological processes , in particular synaptic plasticity , which is thought to be essential in memory and learning.(14 ) furthermore , they have been associated with abnormal neuronal activity leading to a wide range of neurodegenerative diseases such as alzheimer s , parkinson s , huntington s chorea , amyotrophic lateral sclerosis ( als ) , epilepsy , and ischemic stroke .
recently , the structure of a full - length tetrameric glua2 construct was solved to a resolution of 3.6 .(19 ) however , because working with the full - length protein is difficult , it has in the past been more common to perform structure work with the soluble domains ; the ligand - binding core domain(20 ) and the n - terminal domain .
these x - ray structures provide a wealth of information about the interactions of agonists , antagonists , and allosteric modulators particularly with respect to the glutamate receptor subunit glua2 .
many of these structures are of sufficient resolution to have reasonable confidence in the positions of water molecules within the binding pocket .
these observations have been supported by multiple crystal structures along with data from molecular dynamics simulations .
prior to the crystal structures and on the basis of pharmacophoric models , it was thought that glutamate and ampa would adopt similar poses within the binding pocket .
however , crystal structures revealed that ampa adopts a slightly different binding - mode with a water molecule assuming a position that would normally be occupied by the -carboxyl group of glutamate ( figure 1).(24 ) it has also been reported that docking studies that did not take into account the crystallographic waters failed to obtain the correct poses.(49 ) this unexpected difference in binding mode raises some interesting questions : ( i ) what is the underlying cause for the difference ?
( ii ) can the differences in the position of water molecules and binding pose of the ligand be rationalized in terms of interaction energies ? ( iii ) does glutamate cause polarization effects that ampa does not ?
( iv ) can the correct binding mode be predicted by energetic ( enthalpic ) considerations alone ? ( a ) chemical structures of glutamate and ampa .
the 3-oxyanion oxygen and nitrogen from the ring of ampa were thought to mimic the -carboxylate of the glutamate .
cartoons of glutamate from the 1ftj structure ( b ) and ampa from the 1ftm structure ( c ) bound to glua2 along with the water molecules that act as surrogate ligands .
wa sits in the site occupied by left - most ( in this view ) carboxylate oxygen of glutamate . in order to address these questions we use a quantum mechanical level treatment to accurately calculate interaction energies of both glutamate and ampa in the two different binding modes .
ab initio calculations have been used previously in order to account for subtype specificity between glua1 and glua3 where the difference in the binding pocket was a phenylalanine instead of a tyrosine.(50 ) here we use density functional theory ( dft ) to calculate the interaction energies of components of the glua2 binding site with ampa and glutamate .
the calculations demonstrate that interaction energies alone are able to discriminate between the correct binding mode for glutamate but not for ampa .
we also show that the interaction energy of a water found in the glutamate - bound crystal structure ( 1ftj ) is more favorable than its counterpart at a different position in the ampa - bound crystal ( wa in figure 2b ) .
we find that polarization effects are stronger in glutamate than in ampa and that the difference in strain energy between alternative conformations of glutamate is very small but is over 2 kcal mol for the alternative conformation of ampa .
the model - systems have been assembled using the high - resolution crystallographic structures of the glua2 ligand binding core bound with glutamate and ampa available at the protein data bank with pdb code 1ftj ( resolution 1.9 ) and 1ftm ( resolution 1.7 ) , respectively .
since the crystal structures were composed of 3 protomers ( chains a , b , and c ) , only one monomer ( i.e. , chain a ) was selected as the starting geometry for a molecular mechanics energy minimization .
this choice was based on previous work done on glua2 protomers.(51 ) in total , four model systems were prepared ( figure 2 ) : two wildtype where the ligand ( glutamate or ampa ) is in the pose observed crystallographically which we refer to as 1ftj - glu and 1ftm - ampa and two where the ligand is in the alternative pose ( figure 2 ) . for glutamate in the 1ftm structure
this was achieved by converting ampa to glutamate ( by matching equivalent torsion angles , deleting atoms and converting the isoxazole nitrogen to an oxygen ) .
for ampa in the 1ftj structure , ampa was fitted to the c , c , c , c and c atoms of glutamate such that the amide of ampa fitted onto the side - chain carboxylate of glutamate .
missing side - chains of the protein were completed with the what if web interface at http://swift.cmbi.kun.nl / whatif/. all the water molecules reported in the crystal structure were included in the simulations .
counterions were added to neutralize the system and water molecules were randomly replaced with cations and anions to make a 150 mm solution .
the system was then minimized using the steepest descent algorithm , until it converged with a force tolerance of 100 kj mol nm .
gromacs version 3.3.1(53 ) was used in these calculation utilizing the all atom opls - aa force field .
this energy minimized structure was then chosen as the representative structure to assemble the quantum mechanical ( qm ) model .
( e ) schematic diagram indicating the atoms of the system ( taken in this case from the 1ftm with ampa bound ) .
all atoms from residues 649 to 656 are present in the calculations but not all make direct contacts with the ligand .
only the atoms c , c and o from gly 648 are present in the calculations but also omitted here for clarity as are all hydrogen atoms .
figure drawn with ligplot.(77 ) the qm models were assembled by considering the specific ligand of interest , with water molecules within 5 from the ligand and all amino acids within a distance of 10 from the ligand and water molecules . in the end 23
interacting residues from the glua2 receptor were chosen that included glu402 , tyr450 , pro478 - thr480 , arg485 , gly648 - lys656 , thr686 , tyr702 - glu705 , met708 , lys730 , tyr732 ( figure 2e shows a schematic summary of the resulting qm system ) .
our rationale for this selection protocol was to ensure that we had the residues of the protein interacting with the ligand ( and observed waters ) in a system that was computationally feasible .
the numbering employed here is according to the mature sequence as employed by armstrong and gouaux ( 2000 ) for ease of comparison.(24 ) it is important to note that residues arg485 , thr480 and pro478 from domain 1 and ser654 , thr655 and glu705 from domain 2 directly interact with both ligands .
the side - chain of each residue was shortened to keep only those hydrogen - bonded interactions with the ligand or adjacent residues .
additionally , each peptide bond was replaced with a c-h bond to reduce the size of the qm model system .
the final qm models consisted of 357 atoms for 1ftj - glu and 1ftm - glu , 358 atoms for 1ftj - ampa and 361 atoms for 1ftm - ampa .
as such each model has 23 residues , the ligand and 6 water molecules , except 1ftj - ampa , which only maintained 5 water molecules within 5 from the ligand after the energy minimization step .
prior to the calculation of single point interaction energies with density functional theory , each structure was initially optimized using the ab initio restricted hartree
fock ( rhf ) method(56 ) with the 3 - 21 g split valence basis set . to take into account the partially constraining effect of the protein environment on the active - site geometry ,
the side - chains were geometry optimized while the backbone was frozen . also , for contiguous amino acidic residues we froze the positions of atoms involved in the peptide bond .
the rhf/3 - 21 g geometry provided structural parameters that were then used as the input in a subsequent theoretical refinement step with the inclusion of electron correlation effects to obtain more reliable energy .
these single point density functional theory calculations were carried out with the gaussian 03(60 ) program .
ideally one would have used this level of theory to have also performed the optimizations , but these calculations are simply too prohibitive at the present time .
nevertheless , this combined approach should provide a means to compare the different possible modes of interaction .
interaction energies were calculated for a series of fragments ( table 2 ) that form the major components of the binding pocket ( waters , protein , and ligands ) .
the interaction energies for any two fragments can systematically be corrected for by the basis set superposition error ( bsse ) using the function counterpoise method of boys and bernardi.(65 ) as such , the interaction energies can be described as in eq 1
we began by first assessing the influence of different levels of theory on the interaction energies .
we selected two water molecules ( wg and w5 ) from the 1ftj - glu system ( see figure 2a ) , and calculated the interaction energies with the mpw1b95 and b3lyp methods ( table 1 ) on unoptimized systems .
the mpw1b95(63 ) meta - hybrid method was first used in conjunction with three different basis sets .
these included the more mathematically complete 6 - 31 g * and 6 - 31 g * * basis sets as well as the locally dense basis set ( ldbs)(68 ) approach , where the model - system can be partitioned into two very different regions , which are assigned basis sets of different accuracy .
specifically , the atoms directly involved in the formation of hydrogen bonds ( including the ligand and water molecules ) were described by the 6 - 31 g * basis set .
we find that the basis set superimposition error ( bsse ) was the smallest at the mpw1b95/6 - 31 g * * level of theory with comparable interaction energy values for each water molecule ( table 1 ) .
the b3lyp/6 - 31 g * * level of theory was also investigated and in this context the bsse is larger than the mpw1b95/6 - 31 g * * level of theory .
however , although reportedly less accurate in its description of hydrogen - bond interactions than mpw1b95(63 ) it still offers a good compromise between computational expedience and reliability of the values for bsse .
thus we pursued b3lyp/6 - 31 g * * for the series of calculations for all fragments as detailed in table 2 .
fragments are defined as follows : wx ; water molecules where x is 1 - 5 or a or g as described in figure 2 .
ws ; all other water molecules ( e.g. for the w1-ws cell for 1ftj - glu , ws would mean w2 , w3 , w4 , w5 , and wg ) , l ; ligand ( ampa or glu ) , p ; protein , lp ; ligand and protein , wsl ; water molecules and ligand , wsp ; water molecules and protein , wslp ; water molecules and ligand and protein .
analysis of the ligand to protein+water interaction energies ( l - wsp cells , table 2 ) reveals that glutamate is much more favorable in its crystallographically observed mode compared to ampa in its crystal structure ( 1ftm - ampa ) . comparing glutamate in alternative binding poses
, we find that the l - wsp interaction energy for 1ftj - glu is more favorable than 1ftm - glu by 75.32 kcal mol .
however , the situation is not simply reversed for ampa ; in this instance the energies of interaction between ampa and protein are similar in both modes of binding .
the l - wsp interaction energy for 1ftm - ampa ( 327.93 kcal mol ) is slightly less favorable than for 1ftj - ampa ( 329.53 kcal mol ) .
thus glutamate clearly has a strong preference for a binding mode , but ampa it would seem is energetically capable of adopting a glutamate - binding pose .
we then proceeded to examine the origin of this in more detail by examining the interaction energies of water molecules within the binding pocket .
we first discuss what we refer to above as the pharmacophoric water , which is the water that appears to act as a surrogate part of the ligand in either the glutamate ( wg , see figure 2 , panels a and d ) or ampa ( wa , see figure 2 , panels b and c ) complexes . before an in depth analysis
, one might expect that the interaction energy of wg or wa would be more favorable in the poses adopted in the crystal .
however , the interaction energy of the pharmacophoric water with the remainder of the system ( wa - wslp and wg - wslp cells in table 2 ) presents a different perspective of what is observed in the crystal structures .
we find that regardless of the ligand bound wa appears to be iso - energetic with a 0.67 kcal mol difference between the glutamate bound ( 5.59 kcal mol ) mode and the ampa bound ( 6.26 kcal mol ) mode . in the 1ftj - based models
, wg appears to also be iso - energetic albeit with a slight preference of 1.88 kcal mol for the ampa bound ( 9.75 kcal mol ) mode than the glutamate bound ( 7.87 kcal mol ) mode .
one might expect these to be exactly isoenergetic , but the optimizations are done in the presence of ligands and thus there will be some small effects on the final positions of the protein atoms dictated by the ligand . in the 1ftj - based models , wg forms hydrogen bonds ( figures 3a and 5a ) with the backbone nh group of glu705 , the water w2 and an oxygen atom from the ligand ( one of the carboxylate oxygens for glu , and the ring oxygen for ampa ) .
in the 1ftm - based models , wa forms hydrogen bonds ( figures 5a and 6a ) with the oh group of ser 654 , the backbone nh of thr 655 , w5 and two oxygen atoms from the ligand in each case .
the detailed breakdown of how this water interacts with the various components of the binding pocket ( the wg or wa rows in table 2 ) shows that the overall interaction energy ( wg / wa - wslp ) does not arise from the contribution of the ligand solely but instead appears to be related to the whole environment of the system in which each ligand is bound .
hydrogen bond interactions for individual water molecules for the 1ftj - glu model system ( a ) wg , ( b ) w1 , ( c ) w2 , ( d ) w3 , ( e ) w4 , and ( f ) w5 .
hydrogen bond interactions for individual water molecules for the 1ftm - ampa model system ( a ) wa , ( b ) w1 , ( c ) w2 , ( d ) w3 , ( e ) w4 , and ( f ) w5 .
w1 was found to have the least favorable interaction energies in all and indeed in none of the models does w1 make a hydrogen bond with the ligand .
the pattern of interaction energies relates directly to the number and geometry of the hydrogen bonds formed .
w3 makes hydrogen bonds with leu 650 and leu 730 in all four models ( figures 34d ) , and a third hydrogen bond to the ligand .
the interaction energy ( table 2 ) is most favorable in the 1ftj - glu mode and is a result of an optimal arrangement of both ligand and protein .
w4 was found to maintain comparable interaction energies across the models and could be associated with the fact that it forms a tetrahedral association with mostly charged side - chain of the residues ; glu 705 , lys 730 , ser 654 , and thr 655 in all four models .
this water does not form any direct interaction with the ligands and occupies a well - defined site apparently serving a structural role , presumably helping to define the shape of the binding pocket .
hydrogen bond interactions for individual water molecules for the 1ftm - glu model system ( a ) wa , ( b ) w1 , ( c ) w2 , ( d ) w3 , ( e ) w4 , and ( f ) w5 .
hydrogen bond interactions for individual water molecules for the 1ftj - ampa model system ( a ) wg , ( b ) w1 , ( c ) w2 , ( d ) w3 , ( e ) w4 , and ( f ) w5 .
w5 is another water molecule that occupies a well - defined site and is also a well conserved water molecule , found in the majority of published high - resolution ligand - bound iglur structures . in the 1ftj derived models ( figures 3f and 5f )
w5 makes four direct hydrogen bonds to the ligand , leu 650 , thr 655 , and lys 656 and has an identical interaction energy of 14.87 kcal mol regardless if glutamate or ampa is bound . in
the 1ftm derived models w5 can also be considered iso - energetic with a 0.27 kcal mol between the glutamate bound ( 11.76 kcal mol ) mode and the ampa bound ( 12.03 kcal mol ) mode .
it does not make any direct hydrogen bond with the ligand but instead makes a hydrogen bond with wa .
w5 makes three further hydrogen bonds with leu 650 and lys 656 in 1ftm - ampa ( figure 5f ) and with the backbone carbonyl of leu 650 , backbone nh of lys 656 and backbone nh of gly 653 in 1ftm - glu .
a method commonly employed to calculate partial charges for compounds that are not already parametrized in modern force - fields is to use the restricted electrostatic potential ( resp ) fitting method.(69 ) we performed resp calculations on the ligands within the four models in order to assess to what extent polarization from the environment in the different binding modes might be a factor .
the calculations show that there is reasonable agreement at the amino and carboxylic acid groups in all four systems ( which is to be expected ) .
the greatest variation is observed at the oe1 and oe2 atoms of glu , which have an asymmetric charge distribution , presumably reflecting the local environment in each case ( wg or wa ) .
in contrast there is much less variation observed at the oe2 ( or oe1 ) atoms of ampa in 1ftm or 1ftj .
comparison of the resulting partial charge on atoms using the resp(69 ) method ( a ) glutamate in 1ftj structure .
we also examined the internal energies of the different fragments as isolated fragments in the gas phase .
differences between the internal gas - phase energies for the water molecules were all under 0.25 kcal mol . the results for the ligands suggest that gas - phase internal energy of glutamate is raised by 13.35 kcal mol when placed in the ampa - binding mode ( 1ftm - glu system ) .
similarly , when ampa is positioned in the glutamate binding mode , the internal energy of ampa rises by 8.19 kcal mol . when using the polarizable continuum model ( pcm ) of solvent,(70 )
the internal energy for glutamate in the 1ftm derived system is only 0.15 kcal mol higher than the glutamate conformation observed crystallographically in 1ftj .
however , ampa in 1ftj is still 2.06 kcal mol more unfavorable compared to ampa in 1ftm , suggesting that internal strain is a considerable factor in dictating the binding mode of ampa , but is not a contributing factor to the glutamate mode of binding .
the crystallographically determined binding pose of ampa was rather contrary to expectation . prior to structural knowledge
it was anticipated that the 3-oxyanion and ring nitrogen of ampa would superimpose on the -carboxylate oxygens of glutamate .
instead a water molecule occupies the position of one of the carboxylate oxygen atoms ( wa in figure 2b ) .
similarly , the position of the ring nitrogen in the glua2-glutamate complex ( 1ftj ) is also occupied by a water molecule ( wg in figure 2a ) . in this sense we can consider this water molecule as part of the ligand in each case . however it is not clear why this water molecule should preferentially occupy different sites with respect to these ligands and hence why the resulting binding pose for ampa differs from glutamate .
previous docking studies have shown that consideration of this water molecule is essential to retrieve the correct binding pose for ampa and that omission of this water molecule leads to a docking pose that overlays with the glutamate - glua2 complex.(49 ) in the context of drug - design , there has been a lot of work aimed at determining whether water molecules in a binding site can be displaced by modifications to existing ligands . indeed
( rs)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl ) propoionic acid ( acpa ) , an analogue of ampa where the 3-oxyanion moiety is replaced by a carboxylic acid , interacts directly with the side - chain oh of thr 655.(31 ) acpa has both a lower ic50 ( ic50 = 20 nm compared to 79 nm for ampa)(71 ) and lower ec50 ( ec50 = 0.74 m(31 ) compared to 3.5 m for ampa(72 ) ) .
the improvement may be more modest than expected as acpa loses an additional water interaction that ampa makes , the overlay is not quite perfect and there are small differences in the binding pose and the conformation of binding pocket residues . in this study we wanted to examine to what extent
the observed differences in binding orientation between ampa and glutamate could be attributed to stabilization effects of water molecules and how the water molecules interact with the protein and/or ligand . because polarization effects may be critical to this analysis , we used ab initio calculations to calculate the interaction energies between the various components of the binding site .
our calculations show that a simple interaction energy calculation between the ligand and the rest of the system is sufficient to be able to predict the correct mode of binding for glutamate , but not for ampa .
clearly , entropic effects , which are neglected in these calculations , must play a more dominant role in the case of ampa .
table 2 shows that the pharmacophoric water ( wg / wa ) has no energetic preference for the ligand ( glutamate or ampa ) it was crystallized with .
the interaction energies in each case are essentially iso - energetic pointing to the possibility that the binding mode must be due to more than the presence of the ligand alone .
one contributing factor is polarization effects which do not appear to be pairwise additive for these systems .
one notable example is the clearly defined w5 site which influences the binding of the ligand.(48 ) although the interaction energies are iso - energetic for w5-wslp , the breakdown across each subtype is different in each case .
the results here suggest that consideration of the binding pocket in the absence of ligand(s ) may not always give the correct answer without taking into consideration the significant effects from polarization .
this is a particularly important aspect in the context of drug design as there is increasing interest in being able to predict how readily water molecules in the active site are displaced.(5 ) docking programs often have an energetic term that accounts for the internal or strain energy of the ligand and indeed this can be a contributing factor to the binding pose .
the most useful measure of this strain energy though is the comparison between binding modes and in solvent .
our calculations showed that the differences in internal energy for the glutamate conformations using the pcm solvent model are very small ( 0.15 kcal mol ) .
previous calculations of glutamate in solution suggest that the energy difference between two minima for glutamate in solution may be as small as 0.1 kcal mol and that the conformation in the crystal structure is intermediate between these two minima.(73 ) thus internal strain is not likely to be a factor for dictating the pose that glutamate adopts . on the other hand
recently , keith et al.(74 ) demonstrated via the use of ab initio calculations , in conjunction with a solvent model , that bioactive ( as observed by x - ray crystallography ) conformations of ligands are very close to conformations expected in solution , suggesting that the best docking poses would impose little conformational strain energy on the ligand ( less than 0.5 kcal mol in two - thirds of the cases examined ) .
the strain for ampa in the 1ftj is above this level ( at 2.06 kcal mol ) .
together , the results support the notion that scoring functions must incorporate terms other than interaction energies in an accurate fashion if they are to be useful.(75 ) the results from the resp calculations suggest that polarization effects can be quite significant in the case of glutamate but less so for ampa .
the charge assignments in the region of the molecule where the environment is the same in the four systems ( the amino and carboxyl groups ) are in good agreement with each other suggesting that the differences observed for the glutamate side - chain group are genuine and system dependent .
the resp method is one of the standard methods for calculating charges for ligands in force fields for which parameters are not already available .
the variation in these charges shown in figure 7 demonstrates that this may potentially be a source of error if simple point charges are used to evaluate electrostatic contributions in molecular mechanics or docking approaches .
large , conformationally dependent variation in charge assignment for glutamate has been observed before ; odai et al reported the variation in mulliken charges for four distinct conformations of glutamate in solution.(73 ) more systematic work is clearly required in this area to assess how significant these effects are in general .
we also should reiterate that we selected the b3lyp/6 - 31 g * * level of theory as the best compromise between accuracy and computational time .
although we found that basis set superimposition error ( bsse ) was the smallest at the mpw1b95/6 - 31 g * * level ( table 1 ) , it is beyond our current resource to operate at that level .
we have shown here how various components of the binding site of glua2 contrive to dictate the binding mode for glutamate and ampa .
our calculations highlight that for glutamate there is very little internal strain energy for the different binding modes and that it could readily adopt any one of those conformations .
the water , w5 , which could be considered part of the ligand or part of the protein , appears to be energetically favorable regardless of the ligand present ( and indeed appears slightly more favorable when ampa is bound ) .
although simple interaction energies of ligands and waters could partly account for the observed glutamate binding mode , they do not appear to account for the crystallographically observed binding mode of ampa .
although there is more internal strain energy of ampa in the 1ftj - ampa system , the overall interaction energy of ampa with the system is more favorabale ( than in 1ftm ) .
thus , there must be other factors , which control the pose of ampa ; most likely an entropic contribution , which is not considered here .
calculations for entropic calculations are beyond the scope of the current approach ( optimizations would be needed for every fragment ) , but is something that could be performed in future studies as computational power increases . although interaction energies can go some way to providing insight into what factors are controlling binding , they do not provide a complete picture .
there are many reasons why compounds may adopt different binding modes within a receptor , ultimately dictated by the free energy of binding , but with many different contributions . the problem of computing that free energy is complex because often the difference in energy that dictates different binding poses is a very small difference between very large numbers .
thus we must strive to be as accurate as possible if we are to make progress on this front .
an accurate consideration of the role of waters within the binding pocket is going to be critical .
our results suggest that for establishing trends , treatment at the b3lyp/6 - 31 g * * level is sufficient , but that absolute values are in general much lower than that reported for mpwb95/6 - 31 g * * for two test cases .
finally , the results also indicate that polarization effects could mean that initial partial charge assignments based on gas - phase calculations may lead to problems .
having said that , there is much work in progress in developing polarizable models for molecular mechanics,(76 ) so there is good reason to be optimistic on that front . | it is becoming increasingly clear that careful treatment of water molecules in ligand
protein interactions is required in many cases if the correct binding pose is to be identified in molecular docking .
water can form complex bridging networks and can play a critical role in dictating the binding mode of ligands .
a particularly striking example of this can be found in the ionotropic glutamate receptors . despite possessing similar chemical moieties , crystal structures of glutamate and -amino-3-hydroxy-5-methyl-4-isoxazole - propionic acid ( ampa ) in complex with the ligand - binding core of the glua2 ionotropic glutamate receptor revealed ,
contrary to all expectation , two distinct modes of binding .
the difference appears to be related to the position of water molecules within the binding pocket .
however , it is unclear exactly what governs the preference for water molecules to occupy a particular site in any one binding mode . in this work we use density functional theory ( dft ) calculations to investigate the interaction energies and polarization effects of the various components of the binding pocket .
our results show ( i ) the energetics of a key water molecule are more favorable for the site found in the glutamate - bound mode compared to the alternative site observed in the ampa - bound mode , ( ii ) polarization effects are important for glutamate but less so for ampa , ( iii ) ligand system interaction energies alone can predict the correct binding mode for glutamate , but for ampa alternative modes of binding have similar interaction energies , and ( iv ) the internal energy is a significant factor for ampa but not for glutamate .
we discuss the results within the broader context of rational drug - design . |
diffuse large b cell lymphoma ( dlbcl ) is the most common lymphoid malignancy in adults and the most frequent subtype of non - hodgkin lymphoma ( nhl ) in all countries around the world and every age group .
dlbcl is found most commonly in people who are middle - aged or elderly , with the median age at diagnosis of dlbcl in the sixth decade , and men are slightly more likely to develop dlbcl than women . despite being classified as a single disease entity by the world health organization , dlbcl is a remarkably heterogeneous disease with considerable variation in clinical behavior , response to therapy , and long - term outcome ( fig .
recent studies involving gene expression microarray analysis of dlbcl have revealed significant heterogeneity within this diagnosis .
the international prognostic index ( ipi ) , which includes five parameters ( age , performance status , stage , lactate dehydrogenase level , and extranodal site involvement ) , is the most commonly used means of risk stratification in dlbcl and has been further validated in the rituximab era .
however , within the low or low - intermediate ipi group , there currently is no reliable way of prospectively identifying the subset of patients destined to do poorly , in terms of either primary refractory disease or an early relapse .
patients with identical ipi scores may exhibit striking variability in outcome , suggesting the presence of significant heterogeneity within each ipi category .
to predict the prognosis of patients with dlbcl at diagnosis , recent studies have examined the molecular origin of dlbcl to identify markers that stratify dlbcl cases based on the cell of origin [ 3,5 - 9 ] .
recent attempts using gene expression profiling ( gep ) or immunohistochemical ( ihc ) markers to identify the cell of origin in dlbcl or the activation / suppression of signaling pathways are likely to be more successful in increasing our understanding of the biology of dlbcl and predicting the response to therapy and prognosis than the standard morphologic and clinical criteria used to date .
gep has revealed that dlbcl consists of at least three major subtypes derived from b cells at different states of differentiation and with unique molecular pathogenesis : germinal center b cells ( gcbs ) , activated b cells ( abcs ) , and primary mediastinal b cells .
dlbcl is typically treated with combination chemoimmunotherapy that includes the antibody rituximab and anthracyclines [ 11 - 15 ] .
various regimens cure approximately 60% to 70% of patients with dlbcl ; however , some patients either fail to respond to rituximab - based therapy or relapse early , or experience a poor outcome with second - line or salvage therapies .
common treatment algorithms for the management of dlbcl are divided into strategies for localized disease ( ann arbor stages i and ii ) and advanced - stage disease ( stages iii and iv ) . until recently , cyclophosphamide , hydroxydaunorubicin , vincristine , prednisolone ( chop )
chemotherapy administered every 21 days ( chop21 ) remained the standard therapy for dlbcl , with a long - term overall survival ( os ) rate of approximately 40% .
in the 1980s , several studies were performed using aggressive combination - chemotherapy regimens such as macop - b and promace - cytabom in an attempt to improve the results of dlbcl treatment but these programs were costly , difficult to administer , and appeared to be more toxic than chop [ 17 - 19 ] .
the southwest oncology group ( swog ) and the eastern cooperative oncology group ( ecog ) initiated a prospective , randomized , phase iii trial that compared chop with three aggressive multi - agent regimens .
when compared with these intensive chemotherapy regimens , the standard chop regimen produced similar survival outcomes in patients with advanced nhl .
however , fatal toxic reactions were less common in patients treated with chop , thus establishing chop as the standard of care for patients with dlbcl .
this finding has been confirmed by other trials comparing more aggressive chemotherapy regimens with standard chop therapy .
several trials have subsequently explored modifications of the chop regimen based on dose - intensity and dose - density in an attempt to improve its efficacy [ 22 - 24 ] . in 1997 , rituximab became the first monoclonal antibody approved for use by the food and drug administration for follicular lymphoma , and this immunotherapy was soon applied to dlbcl and other b - cell nhls .
rituximab is an antibody directed against the cd20 protein , which is primarily found on the surface of b cells and is present on many lymphoma cells .
although the mechanism is not completely understood , rituximab is thought to induce lysis of lymphoma cells through complement - mediated cytolysis , antibody - dependent cell cytotoxicity , and direct induction of apoptosis .
a large randomized phase iii study demonstrated improved os in patients with dlbcl who were treated with rituximab with chop ( r - chop ) therapy .
other studies showed that combined rituximab and chemotherapy clearly prolonged event - free survival ( efs ) and os in elderly patients .
the mabthera international trial group study compared a chop - like chemotherapy regimen and the same regimen with the addition of rituximab in patients under 60 years of age with good prognosis and demonstrated prolonged efs and os in the rituximab - treated group .
based on the results of these clinical trials , r - chop therapy is now considered to be the ' standard therapy ' in dlbcl , especially for young low - risk and elderly dlbcl patients . however , it has not yet provided a satisfactory outcome in patients in the high - risk group according to ipi classification .
the benefit of 3 cycles of chop followed by involved field radiotherapy ( ifrt ) ( 5-year - os of 95% ) in patients with limited - stage dlbcl ( 60 years or younger with no adverse risk factors ) was confirmed in a series from the british columbia cancer agency .
the ecog 1484 study showed that the addition of ifrt to chop ( eight cycles ) prolonged disease free survival ( dfs ) in patients with limited - stage dlbcl who had achieved complete remission ( cr ) compared with chop alone ( 6-year - dfs 73% for ifrt plus chop vs. 56% for chop alone ) .
however , in the gela lnh 93 - 4 study , the addition of radiotherapy to four cycles of chop did not provide any advantage over four cycles of chop alone for the treatment of elderly patients with low - risk localized aggressive lymphoma . in the swog 0014 study , the addition of rituximab to chop ( three cycles ) and ifrt showed efficacy in patients with limited - stage dlbcl . in historical comparison , these results were better than those for patients treated without rituximab .
r - chop ( three cycles ) with ifrt or r - chop ( six cycles ) with or without ifrt was recommended for patients with non - bulky ( less than 10 cm ) dlbcl .
r - chop21 chemotherapy has been the standard treatment for patients with advanced stage dlbcl based on results of the gela study demonstrating that the addition of rituximab to chop21 improved progression - free survival ( pfs ) and os in elderly patients with advanced dlbcl .
prior to the introduction of rituximab , six cycles of dose dense chop ( chop14 ) as first - line therapy was found to be superior to six cycles of chop21 in patients older than 60 years . in the ricover 60 trial ,
the addition of rituximab to six or eight cycles of chop14 ( r - chop14 ) improved clinical outcomes in elderly patients compared with chop14 alone . over a median observation time of 82 months
ongoing randomized studies are evaluating the role of r - chop14 versus r - chop21 .
although randomized trials have found the french acvbp - r regimen to be superior to r - chop in younger patients , toxicity precludes its use in older patients .
dose - adjusted ( da ) r - epoch has shown significant activity in untreated patients with dlbcl , and an ongoing phase iii randomized trial is evaluating da r - epoch versus r - chop in untreated patients with dlbcl .
to segregate dlbcl into biologically meaningful subgroups that might allow identification of rational therapeutic targets , the leukemia and lymphoma molecular profiling project began gene expression analysis of dlbcl biopsy samples using dna microarrays and identified biologically distinct and prognostically meaningful molecular subgroups of dlbcl .
for example , gcb and abc dlbcl subtypes are derived from b cells at different stages of differentiation .
gcb dlbcl appears to arise from gcbs , whereas abc dlbcl likely arises from post - gcbs that are blocked during plasmacytic differentiation .
analysis of molecular subtype and outcome following upfront chop treatment shows a statistically significant difference in 5-year - os of the dlbcl subtypes : 59% for gcb dlbcl and 31% for abc dlbcl , independent of ipi risk group . because this analysis was performed on biopsies obtained in the pre - rituximab era ,
a second analysis was performed on 233 biopsies obtained from patients treated with r - chop .
similarly , patients with gcb dlbcl had a more favorable survival than those with abc dlbcl , with 3-year - os rates of 84% and 56% , respectively ( p < 0.001 ) , and , as expected , the os of both gcb and abc dlbcl was better than in the pre - rituximab era .
, investigators have developed ihc models , and immunostaining algorithms have been used to differentiate between these two subtypes using combinations of cd10 , bcl6 , irf4/mum1 , gcet1 , and foxp1 . despite variable reproducibility , these approaches have successfully distinguished gcb from non - gcb dlbcl in a number of clinical trials .
although the technology of ihc is more established than that of gep it is not without standardization and reproducibility issues , highlighting the fact that even apparently simplified approaches have limitations and are not always reliable .
recent comparative analysis revealed that the rate of misclassification using ihc is high , especially for gcb subtypes , ranging from 30% to 60% .
this study also showed that gep successfully predicted pfs and os based upon gcb versus abc subtypes , whereas none of the five ihc algorithms was able to do so .
attempts to adopt ihc surrogates for gep findings have met with only modest and controversial success .
it is not necessary to perform any kind of genetic testing to render a diagnosis of dlbcl .
however , it is clear that genetic factors and/or the cell of origin are key determinants of specific subtypes and prognosis .
so far , none of the fascinating data emanating from gep and other technologies have translated into routine clinical practice .
the contemporary relevance of the role of gep and/or the use of ihc surrogates in the rituximab era is somewhat controversial .
it has been proposed that bcl2-positive dlbcl benefits from the addition of rituximab to chop chemotherapy , whereas bcl2-negative cases do not .
other studies suggest that the addition of rituximab to chop benefits bcl6-negative dlbcl , but not bcl6-positive cases .
it therefore appears that patients with abc dlbcl benefit from the addition of rituximab , but those with gcb dblcl do not .
some reports suggest that the use of rituximab eliminates the prognostic differences between these two groups [ 48 - 50 ] although other studies do not support this notion .
even though gcb dlbcl has a better prognosis than abc dlbcl , more than of 30% of patients are not cured .
bcl6 is an important modulator of b cell development in the germinal center , and mutations / translocations in bcl6 enhance its inhibitory effects on apoptotic stress responses and promote proliferation , both of which are associated with treatment failure [ 51 - 55 ] .
an interesting and potentially important observation is the effect of topoisomerase ii inhibition on bcl6 expression through ubiquitin - mediated protein degradation and possibly transcriptional inhibition .
the german high - grade lymphoma study group showed that addition of the topoisomerase ii inhibitor etoposide to chop ( choep ) significantly improved the efs of younger , but not older , patients with untreated dlbcl .
the higher frequency of gcb dlbcl in younger patients may explain why the benefit of etoposide was only found in patients under 60 years and not in older patients .
interestingly , the positive effect of including etoposide in choep was lost when rituximab was also added ( r - choep ) .
this may reflect the overall salutary effect of rituximab on the outcome of both gcb and abc dlbcl , rather than a specific effect on bcl6 . in this regard , the da - epoch - r regimen , which was designed to inhibit topoisomerase ii ,
might be particularly effective in gcb dlbcl , in part due to its effective inhibition of topoisomerase ii and bcl6 .
abc dlbcl is characterized by the expression of genes associated with survival and proliferation and has an inferior clinical outcome . based on in vitro evidence that the proteasome inhibitor bortezomib blocked degradation of phosphorylated inhibitor of kappa b and consequently inhibited nuclear factor - kappa b activity in abc dlbcl cell lines ,
bortezomib was combined with da - epoch in patients with relapsed / refractory dlbcl [ 57 - 59 ] .
bortezomib alone had no activity against dlbcl , but when combined with chemotherapy demonstrated a significantly higher response and median os in abc dlbcl than in gcb dlbcl ( response , 83% vs. 13% ; p = 0.0004 and os , 10.38 months vs. 3.4 months ; p = 0.0026 ) .
these results suggest that bortezomib enhances the effectiveness of chemotherapy in abc , but not gcb dlbcl , and provide a rational therapeutic approach based on genetically distinct dlbcl subtypes .
when bortezomib was combined with r - chop in patients with previously untreated dlbcl to assess its toxicity and efficacy , there was no difference between patients with gcb and abc dlbcl , suggesting that bortezomib overcame the adverse prognostic effect of the abc dlbcl subtype .
based on these studies , a randomized study of r - chop + bortezomib in untreated patients with abc dlbcl is ongoing ( pyramid study ) .
a recent study suggesting that lenalidomide may be preferentially effective in abc dlbcl also warrants further investigation .
although the adoption of r - chop as the new standard of care has improved outcomes for dlbcl , many patients still relapse . in such cases ,
the standard approach for fit patients with dlbcl has been to proceed toward salvage therapy and consolidation with autologous stem cell transplantation ( asct ) .
this study reported a significantly superior os and efs in patients who underwent salvage asct .
based on this study , asct has become the standard of care in patients less than 60 years old with chemosensitive relapsed or primary refractory aggressive nhl .
several regimens exist for salvage lymphoma therapy including ifosphamide , carboplatin , etoposide ( ice ) , etoposide , methy prednisolone , high - dose cytarabine , cisplatin ( eshap ) , dexamethasone , cisplatin , cytarabine ( dhap ) , and dexamethasone , cisplatin , gemcitabine .
. although the standard of salvage therapy is still being debated , the addition of rituximab to the salvage regimen appears to benefit relapsed patients , especially those previously unexposed to rituximab .
the hemato - oncologie voor volwassenen nederland group randomized relapsed patients to dhap with or without rituximab .
after two cycles , 75% of the patients in the rituximab with dhap ( r - dhap ) arm had responsive disease compared with 54% in the dhap arm ( p = 0.01 ) . with a median follow - up of 24 months , there was a significant difference in pfs ( 52% vs. 31% ; p < 0.002 ) and os in favor of the r - dhap arm .
moreover , rituximab does not appear to impair stem cell engraftment or adversely affect transplantation toxicity and is associated with improved pfs when administered before asct for dlbcl .
one study conducted a retrospective review of patients treated with rituximab with ice ( r - ice ) and compared them with historical controls treated with ice alone .
r - ice given for three cycles produced a cr in 53% of patients , and none of the patients had treatment - related toxicity that precluded asct .
it is important to note that patients in both studies had received prior induction chemotherapy without rituximab .
another study showed that among patients with relapsed or refractory dlbcl who received rituximab with eshap as salvage therapy with curative intent , those previously exposed to rituximab had very low cr and overall response rates .
the most effective regimen for salvage chemotherapy after r - chop failure was addressed by a prospective multicenter phase iii study collaborative trial in relapsed aggressive lymphoma , in which dlbcl patients were randomized to receive salvage r - ice or r - dhap .
there was no statistical difference between r - ice and r - dhap in overall response rate ( 63.5% vs. 62.8% ) , 3-year - pfs ( 31% vs. 42% ) , and 3-year - os ( 47% vs. 51% ) , suggesting that either regimen can be used for salvage therapy . because nearly all patients with dlbcl currently receive front - line r - chop , these data call into question our current strategies for salvage therapy , particularly for patients who relapse within 1 year of initial therapy .
the parma study did not enroll patients over 60 years old , and there are no comparative data for asct versus non - transplantation as salvage therapy in this age group .
two non - randomized studies have been published since 2000 comparing the outcomes of autologous versus myeloablative allogeneic stem cell transplantation ( sct ) as treatment specifically for dlbcl patients .
one study reported that allogeneic sct patients had significantly worse 1-year - rates of os , pfs , and treatment - related mortality ( trm ) than asct patients , but the differences were not significant at 3 or 5 years .
another study reported a significantly worse 3-year - trm for allogeneic compared with autologous sct patients , but no difference in survival outcomes . neither study reported a significant difference in the risk of relapse or disease progression between the two treatment groups at any time interval .
one randomized study compared autologous peripheral blood sct ( pbsct ) versus bone marrow transplantation ( bmt ) as treatment for patients with aggressive nhl ( 61% with dlbcl ) .
patients who underwent autologous pbsct had a significantly longer os , but not efs , than those who underwent autologous bmt . a study that investigated the impact of three courses of intensified chop versus no chop prior to two cycles of induction followed by first - line asct for patients with de novo aggressive nhl found that patients who received intensified chop had significantly better os and efs than those who did not
dlbcl is a clinically and biologically diverse disease that can not easily be subdivided into distinct disease entities because of overlapping morphology and pathogenetic features .
r - chop is the standard therapy in elderly and low - risk young patients . as we better understand the biological explanation for this heterogeneity
, we hope to develop more specific and more effective therapies for high - risk patients .
the ultimate aim is to improve the outcome of patients with dlbcl through the selection of individualized treatment regimens . | diffuse large b cell lymphoma ( dlbcl ) is the most common subtype of non - hodgkin lymphoma in all countries and all age groups .
dlbcl is potentially curable , and the outcome of patients with dlbcl has completely changed with the introduction of therapy involving the monoclonal antibody rituximab in combination with chemotherapy .
nonetheless , relapse is detected after treatment with rituximab , cyclophosphamide , hydroxydaunorubicin , vincristine , and prednisolone in approximately 30% of patients .
it has recently become clear that dlbcl represents a heterogeneous admixture of quite different entities .
gene expression profiling has uncovered dlbcl subtypes that have distinct clinical behaviors and prognoses ; however , incorporation of this information into treatment algorithms awaits further investigation .
future approaches to dlbcl treatment will use this new genetic information to identify potential biomarkers for prognosis and targets for treatment . |
osmotic demyelination syndrome ( ods ) , also known as central pontine myelinolysis ( cpm ) , is a condition that is associated with rapid correction of sodium levels or fluid shifts .
classically , this is associated with hyponatremia , but it can also occur in the presence of normonatremia .
outcomes are variable , with almost one - third of patients not having a favorable prognosis .
we present a case of ods in chronic kidney disease having normonatremia throughout and highlight the various aspects related to this condition .
an 18-year - old male was a case of chronic interstitial nephritis end - stage renal disease ( esrd ) detected 1 year back .
he was non - oliguric and was on medical management , namely recombinant erythropoietin , alfa calcidiol , phosphate binders , amlodipine and hematinics and was on twice weekly maintenance hemodialysis through right brachial arterio - venous fistula .
he presented with complaints of anorexia , nausea , vomiting and loose stools of 2 days ' duration .
the diarrhea was watery , copious , about 10 times per day and was not associated with blood or tenesmus .
he had blood pressure 90/62 mm hg with dry tongue and pallor ; the rest of the general and systemic examination was unremarkable .
his evaluation showed anemia ( hemoglobin -10.2 gm / dl , normocytic normochromic ) , normal leukocyte count , azotemia ( serum urea -111 mg / dl , creatinine -8.4 mg / dl ) , serum electrolytes : sodium -136 meq / l , potassium 4.9 meq / l and bilaterally shrunken kidneys on ultrasonography ( right -6.8 cm , left -5.5 cm ) .
he was managed as a case of acute gastroenteritis with intravenous ( iv ) fluids ( approximately 3 l of normal saline ) , iv antibiotics ( ciprofloxacin and metronidazole ) , session of hemodialysis and other supportive therapy .
but , after 48 h of admission , he developed altered sensorium and had an episode of generalized tonic clonic seizures .
clinically , he was drowsy and confused with a glasgow coma scale ( gcs ) of e4 v4 m5 with no neurological deficit . over the next 24 h
, he worsened to develop slurring of speech , difficulty in phonation and dysphagia and had progressive weakness of all limbs with gcs worsening to e4 v3 m5 .
the pupils were equal and reacting to light , but horizontal conjugate eye movements were restricted .
he had dysarthria , his palatal movements were decreased and the gag reflex was diminished .
there was spasticity with grade 4/5 power in all limbs , brisk reflexes and bilateral extensor plantar response .
an urgent computerized tomography of the brain [ figure 1 ] showed diffuse hypodensities in the pons and midbrain , extending into the middle and superior cerebellar peduncle , cerebral peduncle and bilateral post limb of internal capsule with magnetic resonance imaging ( mri ) of the brain ( done later ) showing large areas of altered signal intensity in these areas with a normal mr angiography [ figure 2 ] .
there was no significant change in his hematological and biochemical investigations . in view of the clinical setting , esrd ,
acute gastroenteritis and dehydration , aggressive infusion of fluids , typical acute progressive neurological involvement involving long tracts , cranial nerves and higher centers and characteristic neuroimaging findings , a possibility of ods was considered .
but it was interesting to note that the patient had normal sodium levels at all times and had no evidence of hyponatremia ( 2 weeks ' before illness 139 meq / l , at presentation 136 meq / l , at onset of neurological symptoms 135
ncct brain of the patient taken at onset showing hypodensities in brain stem magnetic resonance imaging of the brain at onset showing hyperintensities ( red arrows ) in t2wi in the areas of brainstem suggestive of osmotic demyelination he was managed with antiepileptics ( phenytoin 300 mg / day ) , nasogastric tube feeds , alternate day hemodialysis , measures to prevent aspiration , physiotherapy and other supportive care .
he showed gradual improvement over the next 4 weeks . his sensorium improved , weakness resolved and he had an improvement in bulbar functions and was able to ambulate with support .
the repeat mri brain after 8 weeks [ figure 3 ] showed complete resolution of the prior hyperintensities .
magnetic resonance imaging of the brain at recovery taken 2 months later showing resolution of the lesions
ods was first defined and described in 1959 . rapid correction of hyponatremia is an important risk factor for the development of ods .
but , ods has been reported in normonatremic and hypernatremic patients also , especially in association with conditions like chronic alcoholism , liver transplantation , diabetes mellitus , hypokalemia , pituitary surgery , hepatocellular dysfunction , lithium toxicity , hypophosphatemia , chemotherapy and chronic renal failure .
mutism and dysarthria are the heralding symptoms of ods and may be associated with lethargy and altered mental status .
the development of classic spastic quadriparesis and pseudo - bulbar palsy indicates involvement of the cortico - spinal tracts in the pons or midbrain thus termed as cpm .
the patient may develop cranial nerve involvement or ataxia if the condition involves the midbrain , medulla oblongata or pontine tegmentum .
the exact mechanism and explanation of such selective demyelination or preferential location of lesions in the pons or midbrain is not well understood .
there is a predilection of the lesions of ods within areas of rich gray - white matter apposition and is probably because endothelial changes ( due to osmosis ) lead to the release of myelinotoxic factors from the gray matter .
thus , the involvement is more common in the pons or any other area with a rich gray - white matter apposition .
neuroimaging helps in the confirmation of diagnosis , but imaging findings may appear late , for as long as 4 weeks after disease onset .
the mri images are due to edema and demyelination and may take up to 4 weeks to appear .
mri reveals significant involvement of pons in the form of butterfly or trident - shaped lesion in the base of the pons .
it is also important to reiterate that these lesions regress over a period of time and do not require any specific therapy .
our patient possibly developed ods due to multiple factors ( that may have predisposed him to develop osmotic shifts ) including diarrhea , massive iv fluid infusion and hemodialysis .
this case is noteworthy as it shows that ods is not exclusively linked to hyponatremia but may occur with normonatremia or hypernatremia , and underlines the fact that patients of ods may have a favorable outcome with spontaneous recovery clinically and radiologically . | osmotic demyelination syndrome ( ods ) is associated with rapid correction of hyponatremia or fluid shifts , and is characterized by neurological involvement related to pons , brainstem or other areas of the brain .
all possible measures should be taken to prevent this serious disorder .
diagnosing this condition early is very important and requires a high index of suspicion .
the treatment is purely supportive and most patients may show dramatic recovery .
ods occurring in normonatremic and hypernatremic patients is very rare .
we report a case of an 18-year - old boy of end - stage renal disease who presented with an episode of acute gastroenteritis .
he was managed with aggressive intravenous fluids , hemodialysis and other supportive therapy .
but , he developed altered sensorium and seizures that progressed to features of spastic quadriparesis and lower cranial nerve palsy .
neuroimaging showed hyperintensities in pons and midbrain suggestive of ods .
the patient had normal sodium levels at all times and had no evidence of hyponatremia .
the patient was managed with hemodialysis , physiotherapy and other conservative measures and had a gradual clinical and radiological recovery . |
bees and wasps commonly sting because an intruder has neared the hive or nest , which has become quite common in india due to its large rural population and increasing deforestation .
insect stings belonging to hymenoptera such as wasps , yellow jackets , bees , or hornets are generally associated with local reactions and occasionally anaphylaxis .
systemic complications such as acute renal failure , liver dysfunction can rarely occur following multiple stings .
a 55-year - old farmer attended our emergency department with history of multiple wasp stings on his right shoulder and trunk , while working in his fields .
initially , he was treated at a nearby hospital with oral antihistamines , steroids , and local anesthetic application . at 3 days later ,
past medical history was unremarkable . on examination , patient was afebrile with pedal edema .
his pulse rate was 94/min , respiratory rate 18/min and blood pressure of 126/82 mm of hg .
51 sting marks were found on the posterior aspect of neck , anterior aspect of right forearm , both anterior and posterior aspect of his right shoulder and chest wall [ figure 1 ] .
multiple wasp stings on front and back of right shoulder and chest investigations revealed hemoglobin 10.8 g / dl , total count 8320 cells / mm , blood urea 224 mg / dl , serum creatinine 6.2 mg / dl , serum sodium 136 meq / l , potassium 6.2 meq / l , serum bilirubin 2.2 mg / dl , aspartate aminotransferase 689 iu / l , alanine aminotransferase 864 iu / l , lactate dehydrogenase ( ldh ) 1640 iu / l , and creatinine kinase ( cpk ) 89252
his arterial blood gas analysis showed ph 7.31 , pco2 24 mmhg , and hco312 meq / l .
the patient had progressively worsening renal failure and remained oliguric in spite of adequate hydration .
hence , the patient was initiated on intensive hemodialysis , and treated with antibiotics , antihistamines , and diuretics .
he received a total of eight sessions of hemodialysis over a period of 2 weeks .
iu / l , 876 iu / l , and 233 iu / l on 5 , 7 , and 14 day after admission , respectively [ table 1 ] .
he was discharged after 2 weeks of hospitalization with serum creatinine of 2.8 mg / dl and urine output > 1.5 l / day .
bee and wasp stings are commonly observed in our country and are potential environmental hazard .
their venom is a concentrated mixture of various biogenic amines , such as melittin , apamine , phospholipases , hyaluronidase , acid phosphatase , histamine , and kinin .
phospholipase a and surface agents such as mellitin and apamine act on red cell membranes leading to hemolysis . though the exact mechanism of rhabdomyolysis is unknown , it is probably due to direct toxic effect of venom on muscular tissue .
the systemic manifestations are seen only in patients with more than 50 stings and the potentially lethal number of stings has been estimated to be 500 .
common manifestations of hypersensitivity reactions to toxins of insects range from local swelling to angioedema and anaphylaxis .
pain occurs immediately followed by erythematous papular lesions accompanied by urticaria and edema of varying degrees , which resolve in 4 - 6 h. wasp stings can result in multi system involvement ranging from hemolysis , rhabdomyolysis , acute renal failure , disseminated intravascular coagulation , myocardial dysfunction , hepatic dysfunction , and thrombocytopenia , which may occasionally become fatal .
acute kidney injury can occur due to acute tubular necrosis secondary to shock , or pigment nephropathy resulting from rhabdomyolysis and intravascular hemolysis , interstitial nephritis from a hypersensitivity reaction to the wasp venom , or direct nephrotoxicity of venom .
other systemic manifestations include myocardial necrosis and infarction , centrilobular necrosis of liver , and thrombocytopenia as a result of direct platelet toxicity . in a review of
previously reported 24 cases of wasp sting , hemolysis and rhabdomyolysis were observed in 14 out of 21 evaluated cases and 11 out of 19 evaluated cases , respectively .
the most common histological diagnosis was acute tubular necrosis , though acute interstitial nephritis , acute cortical necrosis , and thrombotic microangiopathy have also been reported .
management of these patients includes early correction of hypotension , forced alkaline diuresis in case of rhabdomyolysis and hemolysis , and hemodialysis if required . in
a large case series of 75 patients from china , 7 ( 9.3% ) died , and 8 ( 10.7% ) developed chronic kidney disease ( ckd ) .
further analysis showed no difference in the mortality rates between the modality of dialysis ( continuous and intermittent with or without plasma exchange ) .
wasp sting fatality rate has been found to be 0.02 and 0.2 per million population per year in an australian study and swedish registry , respectively . even though , wasp stings are quite common there are no such data available from india .
since a kidney biopsy was not done , we could not identify the exact mechanism of acute renal failure in our patient . since , the muscle enzymes ( cpk , and ldh ) were highly elevated , and there was no evidence of hemolysis or no prior episode of hypotension , our patient developed acute kidney injury probably secondary to rhabdomyolysis causing pigment nephropathy and acute tubular necrosis .
patients who have sustained multiple stings by bees or wasps should seek medical care as early as possible , even if they are apparently normal .
primary as well as emergency care physicians must be well aware of these complications and investigate actively to exclude anaphylaxis , damage to the kidneys , blood , liver , and muscles .
this case report highlights the importance of early recognition and treatment of acute kidney injury as delay in management may lead to ckd and mortality in a significant number of patients . | in most patients , wasp stings cause local reactions and rarely anaphylaxis .
acute kidney injury and rhabdomyolysis are unusual complications of wasp stings .
we report a case of acute kidney injury and rhabdomyolysis secondary to multiple wasp stings . a 55-year - old farmer developed multi organ dysfunction with acute kidney injury and rhabdomyolysis 3 days after he had sustained multiple wasp stings .
the etiology of acute kidney injury is probably both rhabdomyolysis and acute tubular necrosis .
he improved completely after hemodialysis and intensive care . |
idiopathic intracranial hypertension , or pseudotumor cerebri ( ptc ) , is a condition characterised by raised intracranial pressure not attributable to mass lesions , focal structural abnormalities or csf flow in the orientated and alert patient .
it is a recognised complication of a diverse array of underlying medical conditionsincluding morbid obesity , attributed to raised intra - thoracic pressure , itself secondary to raised intra - abdominal pressure(1 - 3 ) .
these techniques have high failure ratesin the obese , however , hypothesised to be due to the high intra - abdominal pressure in these patients limiting the pressure gradient of the shunt ( 4 ) .
previous studies have demonstrated the role of bariatric surgery in the treatment of ptc , by the reduction of symptoms .
this case report demonstrates the potential role of bariatric surgery in reversing ptc to such an extent that a vp shunt can be removed , thus providing an alternative to shunting as the surgical treatment of choice for ptc in the morbidly obese patient ( 5 ) .
a 28-year - old lady , mother of two and a social work student undertaking her thesis , presented as an emergency to hospital , complaining of a bi - frontal headache , worsening over the last three months with associated nausea .
visual field disturbances had been noted for the previous two weeks . on the day of admission
, she described the visual disturbances as a blurring in the right upper quadrant of her visual field .
she used no regular medications , was an ex - smoker and drank alcohol in moderation . on examination
, she remained alert and orientated with a gcs of 15 , she wore glasses and was clinically obese .
the vision in her right eye displayed shimmering in her lateral visual field , and in her left there was clouding in the medial visual field .
visual acuity was 6/6 in the right and 6/9 in the left , correctable with glasses .
was performed , showing an opening pressure of 40 cmsh2o , and closing pressure of 14 cmsh2o .
other investigations demonstrated : a csf glucose of 3.8mmol / l ( blood glucose 5.4mmol / l ) , protein 0.016g / dl and no rbc or wbc on microscopy .
a diagnosis of idiopathic intracranial hypertension was made and , after the therapeutic lp , she was discharged on acetazolamide 250 mg tds , diclofenac 50 mg tds and co - dydramol prn .
unfortunately , her condition was not controlled medically and she had a further ten therapeutic lps ( opening pressures 27 - 53 cmsh2o ) over a 2 year period , as well as various unsuccessful combinations of medications including simple analgesia , acetazolamide , spironolactone and chlorthalidone . with symptoms intractable to medical therapy , she underwent a ventriculo - peritoneal ( vp ) shunt insertion and had complete resolution of symptoms for 18 months when she re - presented with headaches .
shunt malfunction was excluded on 2 occasions over the following year with an lp ( opening pressure 23 ) , ct scan , shunt series imaging and intra - cranial monitoring which showed no spikes in icp outside normal pressures .
in january 2006 , the patient was able to secure funding from the primary care trust exceptional funding panel to undergo gastric banding surgery .
she had been overweight from childhood , with marked weight gain during her two pregnancies .
she had multiple failed attempts at dieting and her body mass index ( bmi ) at the time of referral for bariatric surgery was 41 .
she was fully assessed by the multi - disciplinary team including endocrinologist , specialist nurse counsellor , dietician and surgeon before undergoing laparoscopic gastric banding surgery using a midband ( medical innovation developpement , limonest , france ) . under the careful observation of clinicians and nurse specialists she underwent incremental band inflations resulting in 30 kg weight loss over a 12 month period .
significantly , during this period , her headaches abated , and the medications intended to control her ptc were reduced and ultimately stopped .
her weight has remained stable and her symptoms have not returned over a one year period leading to a decision to remove her vp shunt .
while there is undoubtedly a relationship with obesity the precise pathological mechanisms remains under debate .
sugarman et al ( 6).postulate that raised intra - abdominal pressures directly induce raised intra - thoracic pressures , thus raised central venous pressures and so ptc .
however , walkernotes they did not explain why the pulmonary artery pressures were higher in their obese patients with ptc than in equivalently obese patients without ptc ( 7 ) .
bariatric surgery as treatment for ptc does not provide an immediate resolution of intracranial hypertension . thus , the patient at acute risk as a result of ptc would be better served with alternative treatments e.g. emergent optic nerve fenestration for those at risk of blindness ( 8) .
however , in patients with chronic symptoms who are not at immediate risk of complications , bariatric surgery should be considered .
this case report clearly demonstrates how laparoscopic gastric banding led to a reduction in the patients csf pressure and resolution of symptoms sufficient to allow removal of her vp shunt .
this occurred after 5 years of medical therapy and 12 lumbar punctures had failed to produce sustained improvement in her condition .
weight loss surgery has been shown to be the only reliable method of producing significant and sustained weight loss in the morbidly obese population(9 ) .
current laparoscopic approaches mean that such surgery can be performed with low morbidity and mortality even in the super - obese ( bmi > /=50 ) ( 10 ) . with the significant risk of complications and side effects in vp shunting , and with the potential to also relieve other obesity related co - morbidities , laparoscopic bariatric surgery is an exciting alternative to conventional treatment of ptc . | the cause of pseudotumor cerebri ( ptc ) is poorly understood although there is strong evidence that obesity plays a role in its development .
this report describes a patient with medically intractable ptc , who had continued symptoms despite undergoing a ventriculo - peritoneal ( vp ) shunt . following significant weight loss , as a result of laparoscopic gastric banding
, she has been symptom free and off all medications for 11 months allowing vp shunt removal .
bariatric surgery should be strongly considered in morbidly obese patients with ptc . |
recurrent intraarticular hemorrhage in patients with hemophilia leads to chronic synovitis and eventually causes degeneration of the articular cartilage . subsequently
, this leads to arthritis , ankylosis and so on , which seriously inconveniences patients and affects their physical and mental health .
therefore , early treatment of hemophilic synovitis has become a focus of management in haemophilia .
many institutions use arthroscopic techniques to treat the synovitis of hemophilia and significant clinical benefits have been achieved with these techniques .
however , for hemophiliacs , arthroscopic treatment still requires infusion of large amounts of coagulation factors to prevent intraarticular hemorrhages resulting from the surgical trauma .
we have obtained good clinical results in the treatment of hemophilic synovitis with intraarticular injections ofp colloid ( p - labelled colloidal chromic phosphate suspension ) , a pure -particle emitting , nonabsorbable radionuclide preparation.p is selected in the study because it is cheap , easy to obtain and is safe.12 as it reduces tissue trauma , this treatment not only reduces medical costs , it also permits joint function to recover quickly .
we studied the effect of intraarticular injections ofp colloid in haemophilic synovitis of knee at our institution between october 2011 and september 2012 .
the preparation used was a green colloidal suspension with a ph of 6.08.0 and 60% of the colloidal particle size was in the range 2050 nm .
twenty - two patients with hemophilic synovitis of the knee were referred to our hospital for treatment between october 2011 and september 2012 .
all were male and age range was from 7 to 42 years , with an average of 22.3 years .
nineteen patients had hemophilia a and 3 had hemophilia b. all participants provided informed , written consent .
all patients were asked to record the number of bleeding episodes in 6 month just before treatment .
the patients basal coagulation factor viii or factor ix activity was determined to be 0.54.0% , and no anti clotting factor viii or ix antibody was found in any of the patients prior to treatment .
all patients were treated with recombinant coagulation factor viii or factor ix injection . on the day of the treatment ,
all patients in the study received a dose of recombinant coagulation factor viii or factor ix aimed at attaining a plasma level of 30% of normal and a second injection was given 812 h later .
the prerequisite of intervention is that the patients coagulation factor viii or factor ix activity had increased to a level of 30% .
a hollow needle was inserted into the joint and haematoma was aspirated and 5 mci ofp colloid fluid was injected into the joint .
57 days after treatment , a full range of joint motions was performed 35 times daily .
supplementary coagulation factor viii or factor ix infusions were given intravenously to maintain the level at 30% and the factor viii or ix treatment is over 2 days .
the frequency of intraarticular hemorrhages was recorded at the 6 month , along with a visual analog scale ( vas ) pain scores , hospital for special surgery ( hss ) knee scores , the degree of knee swelling , quadriceps muscle atrophy ( as measured by the lap circumference ) , knee range of motion ( rom ) and the patients level of activity .
the degree of knee swelling was quantified by measuring the midline of the patella on joint extension and the upper patellar circumference .
data obtained before and at 6-month after treatment were analyzed statistically by the rank sum test ( wilcoxon signed - rank test ) .
the preparation used was a green colloidal suspension with a ph of 6.08.0 and 60% of the colloidal particle size was in the range 2050 nm .
twenty - two patients with hemophilic synovitis of the knee were referred to our hospital for treatment between october 2011 and september 2012 .
all were male and age range was from 7 to 42 years , with an average of 22.3 years .
nineteen patients had hemophilia a and 3 had hemophilia b. all participants provided informed , written consent .
all patients were asked to record the number of bleeding episodes in 6 month just before treatment .
the patients basal coagulation factor viii or factor ix activity was determined to be 0.54.0% , and no anti clotting factor viii or ix antibody was found in any of the patients prior to treatment .
all patients were treated with recombinant coagulation factor viii or factor ix injection . on the day of the treatment ,
all patients in the study received a dose of recombinant coagulation factor viii or factor ix aimed at attaining a plasma level of 30% of normal and a second injection was given 812 h later .
the prerequisite of intervention is that the patients coagulation factor viii or factor ix activity had increased to a level of 30% .
a hollow needle was inserted into the joint and haematoma was aspirated and 5 mci ofp colloid fluid was injected into the joint .
57 days after treatment , a full range of joint motions was performed 35 times daily .
supplementary coagulation factor viii or factor ix infusions were given intravenously to maintain the level at 30% and the factor viii or ix treatment is over 2 days .
the frequency of intraarticular hemorrhages was recorded at the 6 month , along with a visual analog scale ( vas ) pain scores , hospital for special surgery ( hss ) knee scores , the degree of knee swelling , quadriceps muscle atrophy ( as measured by the lap circumference ) , knee range of motion ( rom ) and the patients level of activity .
the degree of knee swelling was quantified by measuring the midline of the patella on joint extension and the upper patellar circumference .
data obtained before and at 6-month after treatment were analyzed statistically by the rank sum test ( wilcoxon signed - rank test ) .
in 22 patients who participated in the study , a total of 24 knees were treated .
results for the 24 knees are shown in tables 1 and 2 . the number of hemorrhages in the 6-month period after treatment was significantly less than the number of hemorrhages in 6-month period just before treatment .
comparisons of pre and post treatment parameters were analyzed by the wilcoxon signed ranks test , which showed statistically significant differences in the frequency of intraarticular hemorrhages over 6-month ( p < 0.01 ) , vas pain scores ( p < 0.01 ) , hss scores ( p < 0.01 ) , knee circumferences ( p < 0.01 ) , lap circumferences ( p < 0.01 ) , and knee rom ( p < 0.05 ) [ table 2 ] . however , there was considerable variation in the frequency of intraarticular hemorrhages and vas scores over 6-month posttreatment .
data recorded in the 24 knees evaluated before and after p colloid treatment comparison of pre and post treatment parameters via wilcoxon signed - rank test z and p
recurrent spontaneous hemorrhage in hemophiliac joints leads to local synovial hyperplasia and edema , which eventually leads to synovial hypertrophy .
as hypertrophy of the synovial joints makes them more prone to impact injury , hemorrhage is more likely and a vicious circle is created .
persistent swelling of a joint over 3 months indicates that the patient 's condition has progressed to chronic synovitis .
the clinical manifestations of chronic synovitis are persistent joint swelling , synovial hyperplasia and articular cartilage damage.3 inflammation persisting for more than 6 months can cause degenerative changes of the joint and further development of the disease will result in fibrosis of peripheral articular tissue , progressive joint degeneration and diminished joint function and ultimately lead to serious consequences that impact the quality - of - life.4 recurrent spontaneous joint bleeding in hemophiliacs has mainly been treated by supplementary coagulation factors , joint puncture and intraarticular haematoma aspiration.56 however , as haematoma aspiration can not reduce synovial inflammation , there will still be a high hemorrhage rate when coagulation factors have been fully metabolized . in such cases
, synovectomy has been performed after arthroscopy , in order to resect the hyperplastic synovial tissue and thereby reduce bleeding . although arthroscopic synovectomy has achieved good results , large amounts of coagulation factors are necessary perioperatively to avoid bleeding caused by the arthroscopic surgical trauma .
this creates a substantial financial burden on patients , their families and the society in general . in the 1970s ,
ahlberg 7 proposed the use of radionuclides in the treatment of hemophilic synovitis and reported that this type of treatment requires only a simple operation and is characterized by minimal trauma , less use of supplementary clotting factors , and only a short hospitalization time.8910 our results indicate that clinical symptoms and the frequency of hemorrhage can be significantly improved by intraarticularp colloid injection .
the degree of improvement showed no clear correlation with the patient 's age , type and grade of hemophilia , or previous treatment .
overall , these results suggest that the usage of invasive treatment could significantly improve patients subjective symptoms and the frequency of intraarticular hemorrhage .
intraarticular injection ofp colloid may be associated with some adverse events.11 although local complications after radioactive synovectomy are rare , local joint swelling , and pain may occur within 648 h after injection .
there may also be rare instances of local lymphedema or fever , but these symptoms are self - limiting and can be managed by topical application of ice packs , etc . , without requiring further special treatment .
more serious local complications include necrosis of surrounding skin and soft tissue caused by reflux leakage of radionuclides along the puncture needle tract . in our experience ,
following injection of the radionuclide into the articular cavity with an injection of a corticosteroid can avoid the above complications , and no instances of local necrosis were seen during followup of our patients .
however , there have been a few reports in the literature of needle tract ulcers and tissue necrosis surrounding joints.1213 to avoid these complications , it is advisable that that needle puncture should only be performed by experienced physicians , ensuring that the needle is indeed in the articular cavity .
another potential adverse consequence of intraarticular injection of radionuclides is loss of the articular cartilage .
-rays emitted by colloidal particles are swallowed by synovial macrophage phagocytosis and become parcels , but some radiation damage of cartilage and subchondral bone is inevitable .
although studies have shown that mature cartilage is resistant to -rays , small articular cartilage damage may still be a problem.1415 but , potential cartilage damage by - emitters is inferior to the much more damage due to the ongoing bleeding events or synovial inflammation .
it was suggested that radiosynovectomy should be considered the initial procedure of choice for the treatment of patients with hemarthrosis in hemophilia.16 in conclusion , the treatment of hemophilic synovitis of the knee with intraarticular injection ofp colloid proved to be a simple , safe , reliable , economical and practical procedure with few complications and other joints may be treated as well .
moreover , the limitation of our study is that the sample size is too small because the incidence of hemophilia is rare and not all of them are treated by this method .
hemophilia treated by this method will relapse because this treatment only alleviates the symptoms of arthrosynovitis induced by bleeding .
| background : chronic synovitis is a consequence of recurrent intraarticular hemorrhage in patients with hemophilia .
eventually , synovitis leads to degeneration of the articular cartilage , with serious consequences that impact the quality - of - life in hemophiliacs .
the aim of our study was to investigate the short term clinical effects of intraarticular injection of the radionuclide preparation32p colloid ( 32p - labelled colloidal chromic phosphate suspension ) on recurrent intraarticular hemorrhages in patients with hemophilic synovitis of the knee.materials and methods : patients who met the inclusion criteria ( n = 22 ) were enrolled in an open - label study between october 2011 and september 2012.32p colloid was injected into the knee joint and patients were followed up over 6 months after treatment .
hemorrhage frequency , visual analog scale pain score , hospital for special surgery knee score , knee circumference , upper knee circumference , knee diameter , and knee range of motion ( rom ) were compared before and after treatment with intraarticular32p colloid injection.results:in 24 knees evaluated in 22 participating patients , there was a significant reduction in the number of hemorrhages after32p colloid treatment , along with significant pain relief .
however , there were no statistically significant changes in the degree of joint swelling , degree of muscle atrophy and knee rom between the pre and post treatment evaluations.conclusion:the frequency of joint hemorrhage in patients with hemophilic knee synovitis can be significantly reduced and local symptoms can be improved in the short term by intraarticular injection of32p colloid . |
the ingestion of instruments or materials used in various dental procedures may occur accidentally in dentistry .
foreign bodies vary in size and shape and range from burs , posts , root pieces , teeth , orthodontic brackets , endodontic instruments ( files , broaches ) , impression materials , implant components , and restorations [ 1 , 2 ] . some objects are made of materials that lack radiopacity , which makes them impossible to identify and locate ; diagnostic bronchoscopy / endoscopy or computed tomography for localization is then required [ 3 , 4 ] .
foreign body ingestion is a commonly seen accident in emergencies , usually in children ( 80% ) , elderly , mentally impaired , or alcoholic individuals ; whereas it may occur intentionally in prisoners or psychiatric patients [ 58 ] .
rarely foreign body ingestion results in serious complications , such as intestinal perforation , bleeding , obstructions or impactions .
the patient position in the dental chair as well as the patient s medical history is important in preventing serious complications .
usually instruments entered the gi tract pass asymptomatically and atraumatically within 2 days to 4 weeks .
however there are many potential sites for impactions , among them the ileocecal valve is the most common site .
approximately seventy five percent of perforations occur at or near this site or at the rectosigmoid junction [ 6 , 9 ] . only 1 percent of ingested foreign bodies cause an intestinal obstruction requiring surgery [ 10 , 11].the aim of this article is to document implant screwdriver ingestion along with its consequences and to offer guidance for prevention and management .
a 69 year - old male patient presented with a chief complaint of missing upper left second molar and mandibular left first molar teeth ; for which implant placement was planned .
implant placement was done successfully and patient was recalled after 4 months for second stage surgery . during second stage surgery while placing a gingival former on the implant in the region of upper left second molar , the screw driver accidentally slipped from the operator s hand .
the operator made an unsuccessful attempt to retrieve the instrument by making the patient spit .
the case was attended by a gastroenterologist and immediately pa chest and abdominal radiograph were taken confirming the screwdriver to be in stomach ( fig 1 ) .
an endoscopy was planned , which was performed under local anesthesia but the instrument could not be retrieved .
patient was kept under observation and advised to consume fiber - rich food to enhance intestinal motility and to regularly examine his stools .
on the second day again radiographs were repeated and this time screwdriver was located in the intestine ( fig 2 ) ; the very same day the patient passed the ingested screwdriver in his stool ( fig 3 ) .
it must be emphasized that preventing complications of foreign body ingestion and aspiration is of great importance .
this applies to the identification of at risk patients by means of comprehensive clinical examination and thorough patient history taking . in our case
the patient was senile and apprehensive ; there was difficulty in screwing the gingival former in the maxillary posterior region of upper left second molar , from where the instrument slipped . as the patient was in the supine position direct access to oropharynx was eminent
although rare , ingestion / inhalation of a foreign body may lead to serious complications ; therefore , immediate radiographic evaluation is a must including pa / lateral chest , lateral neck and abdominal radiographs .
usually , most ingested foreign bodies are expelled in stools without causing any complications in several days to several weeks ; for which conservative management of serial radiographs and fiber rich diet is an initial protocol [ 14 , 15 ] .
if serial radiographs depict the same location of foreign body or there is a sign of abdominal tenderness or hemorrhage then most likely there is retention , obstruction or intestinal perforation for which an invasive procedure is indicated and has to be done as early as possible through gastroscopy for its retrieval .
the mallampati score is assessed by asking the patient ( in a sitting posture ) to open his / her mouth and protrude the tongue as much as possible .the anatomy of the oral cavity is visualized ; specifically , whether the base of the uvula , faucial pillar and soft palate are visible .
depending on whether the tongue is maximally protruded and/or the patient asked to phonate , the scoring may vary .
class iv : only hard palate visible it is emphasized that all practitioners should take preventive steps during treatment like placement of gauze screen across the oropharynx , tying ligature ( dental floss ) to instruments , adjusting chair position ( sitting position prevents aspiration / ingestion and supine position increases the risk of swallowing ) and should be able to manage the patients in emergency situations . sending a patient home in the belief that a foreign body that slipped into the oropharynx has been swallowed and
should a foreign body be ingested / aspirated , the patient must be examined clinically and radiographically ; diagnosis must be performed immediately by a specialist and patient and his family members must be informed .
class iv : only hard palate visible it is emphasized that all practitioners should take preventive steps during treatment like placement of gauze screen across the oropharynx , tying ligature ( dental floss ) to instruments , adjusting chair position ( sitting position prevents aspiration / ingestion and supine position increases the risk of swallowing ) and should be able to manage the patients in emergency situations . sending a patient home in the belief that a foreign body that slipped into the oropharynx has been swallowed and will pass through the gut may be associated with complications and lead to litigation .
should a foreign body be ingested / aspirated , the patient must be examined clinically and radiographically ; diagnosis must be performed immediately by a specialist and patient and his family members must be informed .
this case report illustrates a case of foreign body ingestion in an anxious senile patient having mallampati class 1 , during implant restoration in the posterior maxilla ; proper preventive measures may prevent such complications . | one of the complications during a routine dental implant placement is accidental ingestion of the implant instruments , which can happen when proper precautions are not taken .
appropriate radiographs should be taken to locate the correct position of foreign body ; usually the foreign body passes asymptomatically from gastrointestinal tract but sometimes it may lead to intestinal obstruction , perforations and impactions .
the aim of this article is to report accidental ingestion of 19 mm long screw driver by a senile patient . |
camels are domestic animals in rajasthan , india and are commonly used as a means of transportation in desert where other modes of transportations are nearly impossible .
however , low threshed of tolerance has been observed among them during their breeding season which is from december to march . during such days , people near them become vulnerable to their attacks .
the pattern of injury is not fixed , but it usually involves mandible , maxilla , zygoma , nose , and orbit . about 6070% of all camel bites involve head and neck region due to accessibility . although the exact incidence of camel bite is not known and only a few such cases have been reported ; thus , a detailed discussion of this subject will interest the readers .
this study was conducted at jaipur in coordination with national research center for camels , bikaner , rajasthan and is focused on knowing such an unexpected behavior from an otherwise calm animal which can help in preventing such injuries .
twenty cases of camel inflicted maxillofacial injuries were reported at sawai man singh hospital , jaipur between september 2005 and march 2006 which were included in the study .
some of them were also having associated injuries in spinal cord , upper limbs , and trunk .
out of 20 cases , 19 were adult male ( 95% ) of different age groups ( average 36 years ) , one female ( 5% ) , and none of the child was found injured . at the emergency , after triage primary survey was conducted as per protocols and emergency care was provided as required .
three patients required emergency tracheostomy as an airway management . after stabilizing the patient , thorough examination was conducted from head to toe .
all patients received rabies immunoglobulins ( 40 iu / kg ) , half infiltrated intralesionally , and half given intramuscularly and after receiving three doses of human diploid cell antirabies vaccine they were subjected for final surgical repair .
involvement of mandible , maxilla , nasal bone , and zygoma [ table 1 ] were seen in the most of the cases .
deep infected lacerations involving preauricular , postauricular , cheek , chin , and neck regions were presented .
three patients had a total detachment of central segment of mandibular bone along with dental arch as well soft tissue involving floor of the mouth , base of tongue , soft palate and tonsillar pillars , overlying chin skin , and a part of cheek skin [ table 2 ] .
three cases had a cervical spine injury . different combinations of fracture surgical debridement and wound toileting were done under local anesthesia for few days .
fracture segments were supported with the help of interdental wire or suspension bandage until the final reduction and fixations were carried out .
the goals of the management of maxillofacial fractures were to reestablish proper jaw function and facial esthetics .
most cases required open reduction and internal fixation . the surgical approach varied based on the degree of commution .
eleven patients who had a fracture of symphysis or parasymphysis [ table 1 ] were treated with titanium plates and screws [ table 3 ] .
six patients had a fracture of body of the mandible and condylar neck unilateral and or bilateral [ table 1 ] .
fracture of body of mandible was managed by open reduction and internal fixation and fracture condyles were managed nonsurgically by doing intermaxillary fixation ( imf ) for 23 weeks as a standard protocol .
fractures of midface were reduced and fixed at infraorbital region via infraorbital approach and zygomaticomaxillary and nasomaxillary buttresses were fixed via intraoral approach .
maxillary sinus cavity was packed with betadine - soaked gauze strips , and inferior nasal antrostomy was done which was removed after 2 days .
one patient with loss of soft tissue was managed by pectoralis major myocutaneous flap for oral lining and deltopectoral flap as skin drape [ table 3 ] .
another patient who had loss of central segmental of mandible along with skin of upper and lower lip was reconstructed by costomyocutaneous pectoralis major flap [ figure 1 ] .
the third patient who had a loss of cheek and segment from body of the mandible in an injury from parasymphyseal region to angle of mandible was stabilized with external mandibular fixator . in this case ,
oral mucosal continuity was restored by pedicled forehead flap based on superficial temporal artery and outer surface was covered by occipital hair - bearing flap .
nonvascular ileac crest bone graft was used for bony defect and was fixed with reconstruction plate and screws .
post operative photograph : costomyocutaneous pectoralis major flap was used along with deltopectoral myocutaneous flap postoperatively , cleaning and suctioning of the nasal cavity was regularly done to keep airway free of mucus and blood .
imf was carried for 46 weeks except for condylar fractures where it was done for 23 weeks . patients were kept on regular follow - ups .
the choice of treatment modalities used in this study accomplishes optimal results with the least invasive and most efficient methods available .
the mouth opening and masticatory function were returned to normal in 16 patients ( 80% ) , three patients required prosthetic rehabilitation , and one had severely restricted mouth opening due to loss of oral mucosa and fibrosis .
the fragments completely deprived of their blood supply become nonviable resulted into fragment necrosis and sequestration . those were managed by removal of the plate and necrosed bone followed by delayed bone grafting .
the hot and sandy deserts which cover most of the rajasthan regions allow animals like a camel to survive and thrive .
camels are being used as a mode of transportation and as a source of milk for ages in the villages of rajasthan .
they are very calm and helpful pets but not during the breeding season which is observed between december and march , during which males become very energetic and aggressive . during this time
, small interventions can provoke the camel to attack its own owner or any one in close vicinity .
the head and face of the victim is the most vulnerable part , which is directly attacked . due to large jaws size camel
engulfs the head of the victim and crushes it like a nutcracker resulting severe soft tissue and skeletal injuries to face .
the upper incisor of camel is vertical peg - like while lower incisors are oblique and smaller than upper .
the upper canine is well - developed in the form of recurving ( posteriorly directed ) tusk .
shape of the canine is vertical tusk - like , and it is separated from incisor by a space at alveolar margin . the lower canine bites into the space between the upper incisor and canine . while lower incisor bites against the fibrous pad . when any object comes between the jaws , bending forces
these forces along with recurving canines engage the subject and animal shakes its head to get rid of the victim .
this results in tearing of the tissues caught in between and often causes loss of hard and soft tissue which is severe in nature .
the surgical management of animal bite remains an area of controversy among those who treat them .
the treatment of each particular case depends on factors such as nature of injury , the location of injury , and type of animal .
the primary suturing of the punctured wound is not recommended because they are heavily contaminated .
rabies prophylaxis should be used because it remains the most serious complication possible , secondary to the bite of animal .
communition also places the patients at higher risk for ischemic compromise and vascular necrosis of fragments and thus may lead to nonunion , infection , and in some cases continuity defect . in such cases , reconstruction of both soft tissues and hard tissues
usually , comminuted fractures are caused by missiles injury , direct blow with sharp or blunt objects , or crushing in machine , etc .
this is a type of compression , crushing , and bending injury which is quite unexpected from a pet animal .
severity of injury can be judged by the fact that bones get fractured in several segments and not in a linear fashion .
the displacement of fracture fragment is associated with shearing force generated by shaking movements of camel head .
the study describes the camel bite as a very unusual mode of maxillofacial trauma , frequently encountered in rajasthan , india . the circumstances for all cases were almost similar .
most of the victims were owners of camel and very much familiar with their pet . in
the extent of injury was minor to severe ranges from a minor laceration to total detachment of the jaw and respiratory passage obstruction .
the injuries caused by camel were quite different from other modes of injuries and were not described in literature of maxillofacial trauma .
typical of camel bite is that whole face is crushed between two strong jaws resulted into compression and crushing type of injury , which is surprising and different from other any other animal bite .
this study emphasizes the magnitude of trauma caused by otherwise calm animal during its breeding season which is from december to march .
moreover , knowing such behaviors can prevent a lot of people from getting injured who keep camels as their pet .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s )
has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal .
the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .
| introduction : maxillofacial injuries are presented with many different patterns . it mostly depends upon the mode of injury like physical assault , road traffic accidents , occupational injuries , fall , sport injuries and animal attacks .
animals bites are common with wild animals but attack from an otherwise calm animal like camel is unusual and unexpected . they may cause a severe kind of maxillofacial injury which ranges from minor lacerations to total loss of soft and hard tissues .
such incidences are frequently seen in rajasthan , india where camels are kept as a pet .
present study throws light on literature related to animal bite injuries and their management along with our experience with camel bite injuries.materials and methods : twenty patients ( 19 male and 1 female ) of different age groups with variable extent of maxillofacial trauma induced by camel attacks were included in the study . among them , different patterns of maxillofacial injuries were observed involving both soft and hard tissue.result and conclusion : this study provides the comprehensive incidence , pathophysiology , and management of camel inflicted injuries .
understanding the behavior patterns of this animal may prevent such severe injuries . |
medulloblastoma ( mb ) is the most common malignant tumor in children , accounting for 15 to 25% of all childhood brain tumors192021 ) .
occurrence in the adult population is also well documented , but only accounts for 1% of adult tumors11 ) .
treatment includes surgical resection followed by radiotherapy of the entire neuro - axis and chemotherapy451923 ) .
time to recurrence typically occurs within two years of initial diagnosis in the pediatric population .
tumors that follow collin 's law ( tumor free period of 9 months plus the age at diagnosis ) are considered to be cured11920 ) . however
the locations of recurrences most commonly present as posterior fossa , spinal , supratentorial , or boney metastases23 ) .
supratentorial recurrence is reported to be more common in the subfrontal region1923 ) , while late recurrence of mb in the supratentorial intraventricular compartment is rare17 ) .
a 22-year - old male with a history of a medulloblastoma at 9 years of age , removed surgically and treated with adjuvant craniospinal irradiation and chemotherapy presented with 2.5 weeks of progressive gait ataxia and headache .
ct scan showed an anterior septum pellucidum mass at the foramen of monro with secondary obstructive hydrocephalus ( fig .
the patient underwent bilateral ventriculostomy and external ventricular drain placement with subsequent tumor resection ( fig . 2 , 3 ) .
a 22-year - old male with a history of a medulloblastoma at 9 years of age , removed surgically and treated with adjuvant craniospinal irradiation and chemotherapy presented with 2.5 weeks of progressive gait ataxia and headache .
ct scan showed an anterior septum pellucidum mass at the foramen of monro with secondary obstructive hydrocephalus ( fig .
the patient underwent bilateral ventriculostomy and external ventricular drain placement with subsequent tumor resection ( fig . 2 , 3 ) .
medulloblastoma , a malignant tumor typically arising from the cerebellar vermis in young children and lobes in older children , represents 48% of all intracranial tumors , and is the most common malignant central nervous system tumor of childhood192021 ) , with approximately 80% occurring in patients under 15 years of age21 ) .
it accounts for 1525% of all childhood brain tumors in comparison with only 1% of adult intracranial neoplasms , with a slight male predominance in both groups1920212324 ) .
presenting features of medulloblastoma are generally related to hydrocephalus ( found radiographically in 97% of patients ) and cerebellar dysfunction which include : headache , nausea / vomiting , truncal ataxia , and unsteady gait23 ) .
approximately 83% are found in the midline in children , while 49% of adult tumors are lateral21 ) .
differences in childhood and adult tumors can also be observed in terms of histologic variant .
classical histologic presentation of medulloblastoma includes densely - packed primitive cells with hyperchromatic nuclei , scant cytoplasm , and nuclear molding120 ) .
adults are more likely to have laterally - located tumors , which more often desmoplastic51021 ) .
both tumor types include markers of neuronal lineage , such as class iii beta tubulin and map-2 neurofilaments , whereas more adult tumors will express gfap1020 ) .
mb tends to seed the cerebrospinal fluid resulting in extensive leptomeningeal involvement , and treatment therefore requires surgical resection followed by neuro - axis radiotherapy and chemotherapy7171923 ) .
age at diagnosis has been shown to be a significant predictor of time until relapse24 ) .
the majorities of pediatric recurrences are within two years of initial diagnosis , and are in the posterior fossa192024 ) .
those with tumor - free period equal to the age at diagnosis plus nine months may be considered cured ( collin 's law)14181920 ) . while a good predictor of many childhood tumors , there are known exceptions to collins law for mb1269131822 ) . however , a recent review of 125 patients by massimino et al.1415 ) , gender , age at diagnosis , metastases , and therapeutic protocol were shown to have no prognostic impact . in the event of recurrence ,
relapse at a single site and further out from initial time of diagnosis is considered a more favorable prognostic indicator15 ) .
recurrences are most common in the posterior fossa , followed by spinal , supratentorial and boney metastases23 ) .
supratentorial dissemination is often found in the subfrontal area and may be due to overly generous radiation protection of the orbital roof to prevent irradiation of the cribiform plate , allowing for a nidus of recurrence16 ) .
we present a case of late recurrent mb 13 years after initial diagnosis , again validating the need for long term follow - up in the pediatric population following diagnosis of mb .
supratentorial recurrence of mb not following collin 's law is extremely uncommon , especially within the supratentorial ventricular system .
we present a case of a 22 years old male who presented 13 years following his initial diagnosis of mb with symptoms of obstructive hydrocephalus from a septum pellucidum recurrence .
continued close follow - up is need in pediatric patients after resection and radiation for mb given their unexpected recurrence pattern . | medulloblastoma is a common pediatric tumor typically diagnosed before the age of fifteen .
initial therapy includes surgical resection and radiation of the entire neuro - axis . recurrence is common and typically occurs within 2 years of initial diagnosis .
those fitting collin 's law is considered tumor - free .
we report a case of single supratentorial recurrence 13 years after initial diagnosis . here
we present a 22 year old male presenting 13 years after initial diagnosis with isolated septum pellucidum recurrence .
he underwent complete resection of the tumor .
medulloblastoma is a common in the pediatric population .
late recurrence to the ventricular system is uncommon .
long term follow - up is recommended in these patients . |
angiomyolipoma ( aml ) of the kidney is a clonal neoplasm , derived from perivascular epitheloid cells .
the most common serious complication of renal aml is hemorrhage , especially aggravated by renal trauma .
aml with renal calculus is a challenge for the treating physician because of aml 's vulnerability to bleed .
the blood vessels in aml are thick - walled , tortuous and often have angiomatous arrangement .
the vessels are devoid of all important elastic tissue and instead have a disorganized adventitial cuff of smooth muscle .
anatomically they are devoid of capsule and may extend through the renal capsule into the perinephric space making free hemorrhage ( without temponade ) a serious possibility .
this is the rare situation , where the presence of aml leads to challenging alteration in the standard therapy of the renal stone .
the ultrasound - guided lithotripsy has real - time ability to prevent the shockwaves from traversing the aml at all times .
a 54year - old non - hypertensive and non - diabetic lady presented with flank pain and repeated symptomatic urinary tract infection like fever , dysuria and urgency of micturition .
she was treated with culture - based antibiotic therapy for ten days and was advised swl after culture negativity .
on sonography the patient was found to have a 15-mm right renal pelvic stone with mild hydronephrosis .
on contrast computed tomography ( ct ) urography the lesion was confirmed to be aml [ figure 1 ] .
the hounsfield units ( hu ) of the stone were 900 hu . in view of past history of recurrent infection and relatively lower hounsfield units of the stone
a three - dimensional ( 3d ) reconstruction was done to find out the anatomic co - relation of the aml and renal calculus .
patient was subjected to swl on siemens modularis vario ( erlangen , germany ) having focal zone of 12.1 mm x 130.4 mm and depth of penetration 140 mm .
the imaging modality used was siemens sonoline g20 , with transducer c5 - 2 , with footprint measuring 6.7 cm which enabled us to have a broader field of view .
pre operative ct scan showing right renal calulus with aml lesion the therapy head of siemens modularis vario is angulated at 55 degrees hence the natural course of shockwave travel is demonstrated in figure 2a by yellow line ; the patient was given supine right lateral tilt of 15 degrees so that the aml lesion was away from the focal zone of the lithotripter .
once the stone was localized behind the crosshair , the distance between the aml lesion and stone was always kept more than 6 mm from the edge of the stone considering the diameter of focal zone as 12.1 mm .
the therapy head of siemens modularis vario is angulated at 55 degrees hence the natural course of shockwave travel is demonstrated in figure 2a by yellow line ; the patient was given supine right lateral tilt of 15 degrees so that the aml lesion was away from the focal zone of the lithotripter .
once the stone was localized behind the crosshair , the distance between the aml lesion and stone was always kept more than 6 mm from the edge of the stone considering the diameter of focal zone as 12.1 mm .
patient was well hydrated before the procedure so as to ensure good fragmentation of stone during swl .
treatment was initiated with energy level of 0.1 for first 100 shockwaves so that vasoconstriction would lead to prevention of kidney tissue injury .
gradually , energy was increased after initial 500 shockwaves and maximum of 3.0 energy was reached by the end of 1000 shockwaves .
clouds of echogenicity were seen in the area of the stone . with every consecutive shockwave these clouds of echogenicity progressed through the collecting system indicating clouding effect which suggests adequate fragmentation at around 2900 shockwaves . as ultrasound machine can not directly observe cavitation elements , remnant gas bubbles appear as echogenic region . at the end of 3000 shockwaves
the treatment was terminated as we never wanted the adverse effects of the cavitation bubble .
patient had indwelling foley 's catheter for 24 h post swl to monitor urine output and to watch for hematuria and was discharged one day later . a sonography scan was performed to check for hematoma at the time of discharge .
after one week , the patient was screened by x - ray , which was suggestive of good fragmentation with few residual fragments in the upper ureter along the l3 - 4 vertebrae .
complete stone clearance was confirmed by x - ray kidney ureter bladder ( kub ) at the end of the second week by observing these calculi .
to conclusively diagnose aml , many authors have tried fine needle aspiration cytology ( fnac ) as well as fine needle aspiration biopsy ( fnab ) .
fnab is more reliable , however , fraught with the unwanted and often serious complication of hemorrhage .
thus most amls are diagnosed based on their ct features . extrapolating this data of fnab
, we believe that chances of injury to the aml are high during the puncture .
hence we did not consider doing pcnl ( per cutaneous nephrolithotomy ) in this patient .
kropp had performed percutaneous nephrolithotomy directly through an aml eiley dm had performed percutaneous nephrolithotomy with renal aml with the help of 3d ct imaging to achieve accurate renal puncture and angle during percutaneous nephrolithotomy .
however , a second tract was needed and this was done using standard biplanar fluoroscopic technique which traversed an aml . to avoid such a complication
however , it is done at very few centers therefore we believe that sonography - guided lithotripsy is very safe in the presence of aml .
cavitation erosion is especially observed in the anterior and posterior side of the artificial stone in vitro .
cavitaion plays important role in stone disinegration after the initial spalling effect have disintegrated the calculus .
the collapse of the cavitational bubble is asymmetric , resulting in the emission of a liquid jet that may have significant destructive effects on tissue exposed to swl .
since cavitation is an undisputed reason for renal tissue injury and cavitational bubble occurs at the entry site of the shockwave rather than exit site , our major concern was to place the aml lesion outside the focal zone of our machine .
considering the fact that the diameter of the focal zone was 12.1 mm , the minimum distance required between the centre of the stone and the aml lesion had to be more than 6 mm at all times during swl .
this can effectively be achieved only by real - time usage of sonography and not fluoroscopy .
in such special cases of concurrent aml and renal stone we strongly suggest usg - guided lithotripsy for its real - time ability to avoid shockwaves traversing the aml .
real - time sonography is able to detect any hemorrhage from aml during the procedure which enables us to stop swl on time . | treatment of angiomyolipoma ( aml ) of kidney with stone has been challenging for urologists .
we present our experience of treating the renal stone in the presence of aml with shockwave lithotripsy ( swl ) .
position of the patient with respect to the direction of the shockwaves and accurate knowledge of the dimension of the focal zone are critical aspects of swl . keeping the aml safely away from the focal zone at all times during the procedure is only possible by usage of real - time ultrasonography in lieu of fluoroscopy . |
the action of grasping an object might be performed with different intents : touch , use , move , throw , or pass .
evidence that prior intention shape action kinematics was first provided by measuring prior - to - contact grasping kinematics for reach - to - grasp movements performed toward a bottle filled with water ( ansuini et al .
, 2008 ; see also , marteniuk et al . , 1987 ; ansuini et al . , 2006
; sartori et al . , 2011a ) . by comparing hand shaping across tasks involving different subsequent actions pour the water into a container , throw the bottle , move the bottle from one spatial location to another spatial location
the authors were able to demonstrate how the prior intention in grasping the object strongly affected the positioning of the fingers during the reaching and the contact phases of the movement .
reach - to - grasp for an object variations in the kinematic patterning have been demonstrated for prehensile movements performed with an individual intention and prehensile movements preparing to a subsequent social interaction ( becchio et al . , 2010 ; see also mason and mackenzie , 2005 ; meulenbroek et al .
participants reached toward an object and grasped it either to move it from one spatial location to another ( individual intention ) or to place it into the hand of a partner ( social intention ) .
the results revealed a significant decrease in maximal finger aperture and peak grip closing velocity when the object was grasped to be passed to the partner ( becchio et al .
similarly , ferri et al . ( 2010 , 2011 ) found that when a piece of food was grasped to be placed into the mouth of a human receiver , the final phase of the reaching slowed down compared to when the same action sequence was directed to a mouth - like aperture on the face of a human body shape .
actions such as placing an object into a conspecific 's hand or mouth directly affect the behavior of another agent .
communicative acts , in contrast , aims at influencing indirectly the behavior as a consequence of changing the mental state of the recipient .
successful communication relies on the fact that the recipient understands and recognizes the intention of the communicative act ( sperber and wilson , 1986 ) . to test whether communicative intentions modulate movement kinematics , sartori et al .
( 2009a ) devised a task in which participants used two spherical objects a green and blue sphere to communicate with a partner in a binary code .
participants were asked to select a word ( and thus a color sequence ) and to communicate it to the partner by lifting the spheres in the corresponding order .
relative to the execution of the same action sequence with no - communicative intent grasp an object and simply lift it approach movements to the object were more careful and accurate when the lifting action was performed with the scope to show the object to the interacting partner . taken together ,
these findings contradict the assumption that the same movement can serve different prior intentions ( e.g. , jacob and jeannerod , 2005 ; csibra , 2007 ; kilner et al .
intentions influence action planning so that , although the to - be- grasped object remains the same , different kinematic features are selected depending on the remote goal to be achieved .
the finding that intentions shape action kinematics allows us to refine the question : are observers sensitive to differences in visual kinematics ?
are they able to use these differences to understand other people 's intentions in grasping an object ?
one approach to investigate the contribution of motor information to intention understanding is to use temporal and spatial occlusion methods ( abernethy and russell , 1987 ) .
sartori et al . ( 2011a ) adopted this approach to investigate how well observers can discriminate between cooperative , competitive , and individual intentions on the basis of movement observation .
first , to assess whether intention information was indeed available in the movement stimuli , they analyzed the kinematics of reach - to - grasp movements performed with the intent to cooperate with a partner , compete against an opponent , or performing an individual action at natural or fast speed .
next , to assess attunement to kinematic information , video clips of the same grasping movements were presented to participants in an intention discrimination task . to ensure that only advance sources of information were made available as to judge the model 's intention , videos were temporally occluded at the time the fingers contacted the object so that neither the second part of the movement nor the interacting model , when present , was visible .
the results revealed that observers were able to discriminate between cooperative , competitive and individual trials ( sartori et al .
discrimination performance was similar for full - body video clips and partially occluded video clips , displaying only the arm and forearm of the model .
video clips have the advantage of capturing the near normal visual input that is available when watching the motion of others .
however , because movement information is provided in conjunction with other sources of information , they do not allow determining the specific role of motion cues .
a method employed to isolate the contribution of kinematics is the point - light technique ( johansson , 1973 ) . with this method ,
the movements of a body are represented by a small number of point - lights indicating the major joints of a moving person . despite the drastic degradation of the stimulus
, observers can easily understanding what an actor is doing in a point - light display ( e.g. , dittrich , 1993 ) . from observing a point - light action
2005 ) , gender ( e.g. , kozlowski and cutting , 1977 ; see also , pollick et al .
, 2005 ; richardson and johnston , 2005 ) , age ( e.g. , montpare and zebrowitz - mcarthur , 1988 ) , and emotion of the actor ( atkinson et al . , 2004 ) .
moreover , observers can easily discern activities involving two individuals represented through point - light displays ( mass et al .
2010 ) , being able to use the action of one agent to predict the actions of a second agent ( neri et al . , 2006 ; manera et al .
observers viewing point - light displays of grasping movements can estimate the visual size of the invisible grasped object ( campanella et al . , 2011 ) .
( 2011c ) examined whether they can also discern the intention in grasping the object .
to this end , they presented participants with point - light displays of grasping movements performed with the intent to cooperate , to compete , or to perform an individual action ( figure 2 ) .
point - light clips were temporally occluded at the time the fingers contacted the object , so that the second part of the movement was not visible .
examples of stimuli used in to investigate the contribution of motor information to intention understanding .
( a ) single frames extracted from a video clip representing an individual cooperative action sequence .
( b ) single frames extracted from a point - light clip representing the same cooperative action sequence . adapted from manera et al .
the results demonstrated that participants were able to pick up the intention information available in the kinematic patterns : although discrimination was less accurate than under full - light conditions , observers were nonetheless able to discriminate between cooperative , competitive , and individual grasping actions ( mean accuracy for the video clips = 76% of correct responses ; mean accuracy for the point - light clips = 72% of correct responses ) . in this study
, grasping movements were displayed from a lateral perspective , i.e. , the perspective of passive observer .
a question for future research is whether discrimination of intention is influenced by the viewpoint , i.e. , whether discrimination of intention is facilitated when the action is observed from a view consistent with the observer performing the action or a potential interacting partner performing the action .
during social interaction , understanding others ' intentions is only part of the story ( frith and frith , 2010 ) : predictions about the future course of other 's actions need to be integrated with pre - planned actions .
for instance , when cooperating with a partner to accomplish a task ( e.g. , building together a tower with wooden blocks ) , we might use online action and intention prediction to plan an appropriate response to be performed at an appropriate time ( georgiou et al . , 2007 ) .
but , imagine to be asked to cooperate with a partner who clearly displays the intention to compete , or vice versa .
how would the incongruent attitude of the partner influence the implementation of your action ? translating this scenario into an experimental setting , becchio et al .
( 2008b ) have shown how interacting with a partner displaying an incongruent attitude produces a reversal in the kinematic patterning .
participants were asked to reach and grasp a wooden block either to cooperate with a partner in building a tower or to compete to place their object first in the middle of the working surface . for the congruent trials , the partner a semiprofessional stage actor displayed an attitude congruent with the task instructions : cooperative for the cooperative task , competitive for the competitive task . for the incongruent trials , her attitude was manifestly in contrast with the task instructions : competitive for the cooperative task , cooperative for the competitive task .
results revealed a significant reversal of kinematic patterning for incongruent trials : when cooperating with a partner displaying the intention to compete , the agent 's kinematic pattern became similar to a competitive pattern ; when competing with a partner displaying the intention to cooperate , the kinematic pattern became similar to a cooperative pattern .
these findings might indicate that during incongruent trials participants were able to infer the partner 's incongruent intention and this led to a re - planning of the action sequence . in this interpretation , reversal in the kinematic patterning
an alternative yet not mutually exclusive explanation is that changes in the agent 's kinematics resulted from interpersonal alignment .
when people interact , they become aligned at many different levels , from basic motor programs to high - level aspects of meaning ( frith , 2008 ) .
alignment in action , enabled by in - built motor resonance mechanisms ( see below ) , may allow individuals to automatically adjust their actions to those of another person to achieve a common goal ( knoblich and sebanz , 2008 ; marsh et al . , 2009 ) .
in this view , coordinated resonance might contribute to the emergence of cooperative and competitive patterns .
beyond eliciting coordination , direct perception of intention in action has been proposed to afford specific action plans ( gangopadhyay and schilbach , 2011 ) .
( 2009b ) demonstrated that the social affordance of this gesture can be so powerful as to override the initial motor plan .
on 20% of trials , at the moment the participants started the action toward the objects , a co - experimenter unexpectedly stretched out her arm and unfolded her hand as if to ask for the object .
analysis of the participants ' spatial trajectories revealed a significant veering in the arm trajectory occurring 165 ms following the perturbation .
strikingly , in some trials , participants totally disregarded the instructions and handed the object to the co - experimenter .
no changes in movement trajectory were observed when the human co - experimenter was replaced by a robotic agent or when the perturbation consisted of a human arm conveying no social intention .
ferri et al . ( 2011 ) report a similar perturbation effect for the aperture of the mouth signaling the request to be fed .
exposure to this signal influences both the reaching and the placing phase of action sequences unrelated to feeding , e.g. , reach and grasp a sugar lump and touch with it the forehead of the partner . as for hand request gestures ( sartori et al .
, 2009b ) , changes in movement parameterization are only observed when the partner 's gaze was available , suggesting that gaze acting a as a strong cue to intention ( becchio et al . , 2010)might be critical to activate an appropriate complementary action plan in the observer .
taken together , these findings suggest that during social interaction , agents integrate the predictions about the future course of others ' actions into their own action planning . as a result
, action kinematics does not simply reflect the agent 's intention , but also the intentions of others .
what neural mechanisms mediate this ability to extract intention from motion ? it has been proposed that an important function of the motor system lies in the prediction of others ' actions ( blakemore and frith , 2005 ; wilson and knoblich , 2005 ; prinz , 2006 ) . observing others ' actions
activates corresponding representations in the observer 's motor system and these representations might be used to generate predictions by running an internal simulation ( wolpert and flanagan , 2001 ) .
this simulation is thought to be carried out by neurons in the premotor and the parietal cortex that are active during both action execution and action observation the so - called mirror - neuron system ( rizzolatti and sinigaglia , 2010 ) .
evidence that in humans activity in mirror areas is sensitive to subtle difference in kinematics conveying intention information is provided by two recent functional mri studies .
( 2010 ) found that discriminating between an actor 's intention to move or use an object based on the visual properties of the movement involves multifocal activations within the intraparietal sulcus , a region also involved in planning of grasp - related actions ( tunik et al . , 2007 ) .
( 2012 ) report that in absence of contextual information , observing prehensile movements performed with a social intent relative to prehensile movements performed with an individual intent activates mirror areas , including the inferior frontal gyrus and the inferior parietal lobule ( along with the brain areas with no mirror properties , i.e. , the temporo - parietal junction and dorsal medial prefrontal cortex , which are normally involved in processing social intentions )
. contrary to the assumption that motor simulation merely reflects what an agent is doing ( i.e. , grasping ) , these findings might indicate that simulation processes within the observer motor system integrate why aspects conveyed by action kinematics .
an alternative , non - mutually exclusive explanation is that differential activity within mirror areas reflects the activation of a complementary response .
evidence favoring this hypothesis comes from experiments showing that laboratory training ( e.g. , catmur et al . , 2007 ) and context ( newman - norlund et al . , 2007 ; van schie et al . , 2008 ; sartori et al . , 2011b ) can reverse mirror activity .
for example , newman - norlund et al . ( 2007 ) report that merely changing the context in which an action is embedded modulates mirror activity so that activation in the inferior frontal gyrus and inferior parietal lobule is greater during preparation of complementary than of imitative prehensile actions .
( 2011b ) demonstrate that depending on the context , motor - evoked potentials to transcranial magnetic stimulation reflect the observed movement or the complementary movement .
when an object is present and the observer is implicitly required to act upon the object in response to the observed action , a shift from symmetrical motor resonance to complementary activations of hand muscles is observed . as prehensile movement performed with different intents are likely to evoke in the observer different complementary response , these findings might well explain why activation within mirror areas is modulated by intention .
note than on this account , mirror activation during action observation would not implement a simulation of the observed action , but subtend a direct intersubjective perception of what the other is doing ( gallagher , 2008 ) .
because kinematics retains specificity to the person 's intention in producing a certain action , intention information is potentially available in the human kinematic pattern ( runeson and frykholm , 1983 ) . in this perspective article
we have drawn together studies that highlight the importance of intention - from - movement information in social interaction . by simply observing others ' movements
this knowledge is critical to discriminate between movements performed with different intents , predict what others will do next , and plan an appropriate complementary act in response . a challenge for future research will be to clarify how movement kinematics combines with other sources of information in the online prediction of others ' actions .
there are many situations in which the intention of an observed actor can be unambiguously inferred from goal objects and/or situational constraints .
if the scene involves multiple possibilities of action , however , combining movement kinematics with other information might be crucial for action prediction .
( in press ) found that in action observation settings observers exploit subtle movement cues rather than the direct visual information about target objects and context to predict how an ongoing action will unfold . inasmuch as social interaction is rooted in the actions of the interacting agents
, we would expect reliance on movement kinematics to be even greater during online social interaction .
the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest . | skepticism has been expressed concerning the possibility to understand others ' intentions by simply observing their movements : since a number of different intentions may have produced a particular action , motor information it has been argued might be sufficient to understand what an agent is doing , but not her remote goal in performing that action .
here we challenge this conclusion by showing that in the absence of contextual information , intentions can be inferred from body movement .
based on recent empirical findings , we shall contend that : ( 1 ) intentions translate into differential kinematic patterns ; ( 2 ) observers are especially attuned to kinematic information and can use early differences in visual kinematics to anticipate the intention of an agent in performing a given action ; ( 3 ) during interacting activities , predictions about the future course of others ' actions tune online action planning ; ( 4 ) motor activation during action observation subtends a complementary understanding of what the other is doing .
these findings demonstrate that intention understanding is deeply rooted in social interaction : by simply observing others ' movements , we might know what they have in mind to do and how we should act in response . |
one approach to understanding the molecular mechanisms involved in animal development is to analyse morphological changes in cell positions , movements and divisions when gene expression is perturbed .
because many genes are essential for animal development , a genome - wide gene perturbation analysis of morphological dynamics would provide useful information about the development .
rna - mediated interference ( rnai ) and morpholino techniques can be used for genome - wide gene silencing analyses ( 1,2 ) . in several organisms , large - scale gene - silencing analyses of morphological dynamics
have been performed ( 310 ) . to obtain quantitative information about morphological dynamics from microscopy images , methods based on computer - image processing
such quantitative information enables highly objective comparisons of morphological dynamics and the generation of mathematical models and hypotheses pertaining to animal development , and it thus facilitates the attainment of insights into animal development .
however , before this study , no collection of quantitative information about morphological dynamics under a wide variety of gene perturbations was available .
the nematode caenorhabditis elegans is the only animal for which essential embryonic genes have been identified through genome - wide rnai screenings ( 7,16 ) . here
, we conducted rnai experiments targeting the 97 essential embryonic genes on chromosome iii , and analysed the resultant embryos by four - dimensional ( 4d ) differential interference contrast ( dic ) microscopy .
we then applied our computational method ( 13 ) to the 4d dic microscopy images to obtain quantitative information about cell division dynamics in early c. elegans embryos .
we designed the worm developmental dynamics database ( wddd ) to allow access to this information .
the current version of wddd includes 50 sets of quantitative data from wild - type embryos and 136 sets of quantitative data from rnai experiments , where 72 of the 97 essential embryonic genes on chromosome iii were individually silenced ( i.e. one gene silenced per embryo ) .
we first recorded three - dimensional ( 3d ) time - lapse microscopy images of early c. elegans embryo by using a 4d dic microscope , as described previously ( 17 ) . at each time point , we recorded images of the embryo at 66 consecutive focal planes spaced at 0.5 m intervals . sets of images were recorded at 40 s intervals during the first three rounds of cell division or up to 2 h for embryos whose cell division was very slow . to obtain quantitative information about cell division dynamics from the microscopy images
we automatically detected nuclear regions in the images by distinguishing the image texture in the nucleus from that in the cytoplasm ( figure 1a ) , and grouped nuclear regions corresponding to the same nucleus at each time point .
lastly , we traced nuclear movements and divisions over time by using an object tracking algorithm ( figure 1b ) and obtained the 3d coordinate values of the outlines of nuclear regions and the dynamics of the outlines over time ( figure 1c ) . the errors of automated nuclear detection and nuclear tracking were manually corrected by visual inspection .
( a ) use of computer image processing to detect nuclear regions ( white ) in a dic microscopy image .
dic , dic microscopy image ; epy , local image entropy ; bin , low - entropy regions designated by binary thresholding , nuc , detected nuclear regions .
( b ) use of object tracking algorithm to obtain division dynamics of detected nuclear regions .
( c ) example of dic microscopy images and quantitative information about cell division dynamics ( top ) .
dic , dic microscopy images ; cdd , 4d view of quantitative information about cell division dynamics .
r , indicates that the line contains information about nuclear tracking or information about the outline of the nuclear region .
the numbers following the index g represent time point , identification number ( i d ) of the ancestor of the nucleus at previous time point , unique i d of the nucleus and xyz positions of the centroid of the nucleus relative to the upper - left corner of the image and the top focal plane , where x and y positions are represented by converting 1 pixel to 0.105 m ( middle ) .
the numbers following r represent the start pixel point of the crack code relative to the upper - left corner of the image , focal plane , time point and the crack code that represents the outline of the nuclear region ( right ) .
details of the data format are available at http://so.qbic.riken.jp / wddd/. overview of our computational method for obtaining quantitative information about cell division dynamics .
( a ) use of computer image processing to detect nuclear regions ( white ) in a dic microscopy image .
dic , dic microscopy image ; epy , local image entropy ; bin , low - entropy regions designated by binary thresholding , nuc , detected nuclear regions .
( b ) use of object tracking algorithm to obtain division dynamics of detected nuclear regions .
( c ) example of dic microscopy images and quantitative information about cell division dynamics ( top ) .
dic , dic microscopy images ; cdd , 4d view of quantitative information about cell division dynamics .
r , indicates that the line contains information about nuclear tracking or information about the outline of the nuclear region .
the numbers following the index g represent time point , identification number ( i d ) of the ancestor of the nucleus at previous time point , unique i d of the nucleus and xyz positions of the centroid of the nucleus relative to the upper - left corner of the image and the top focal plane , where x and y positions are represented by converting 1 pixel to 0.105 m ( middle ) .
the numbers following r represent the start pixel point of the crack code relative to the upper - left corner of the image , focal plane , time point and the crack code that represents the outline of the nuclear region ( right ) .
details of the data format are available at http://so.qbic.riken.jp / wddd/. to obtain embryos in which the expression of individual genes was silenced , we used the rnai method .
double - stranded rnas ( dsrnas ) homologous to the genes of interest were produced by using the same pairs of primers as those used in a previous genome - wide screen ( 16 ) .
we targeted all 97 genes on chromosome iii that , when silenced , produced an embryonic lethal phenotype in 100% of offspring in the previous screen ( 16 ) .
embryonic lethality in our rnai experiments was checked both for the progeny on the plate laid by each injected worm and for the recorded embryo on the glass slide .
the current version of the wddd provides information about cell division dynamics during the first three rounds of cell division ( from the one - cell to eight - cell stage ) .
it includes a total of 136 sets of information for rnai embryos corresponding to 72 of the 97 essential embryonic genes on chromosome iii ( 14 sets of information for each gene ; figure 2a ) and 50 sets of information for wild - type embryos .
the information for rnai embryos corresponding to the remaining 15 genes was not obtained because the injected worms produced no embryos , the embryos did not undergo cell division or the embryos had abnormalities in either nuclear appearance or cytokinesis or in their size .
the wddd also provides all sets of 4d dic microscopy images from rnai and wild - type embryos at high resolution of 600 600 pixels ( figure 2a ) .
exp , results of rnai experiments ; dic , datasets of 4d dic microscopy images ; cdd , datasets of quantitative information about cell division dynamics .
exp , results of rnai experiments ; dic , datasets of 4d dic microscopy images ; cdd , datasets of quantitative information about cell division dynamics .
for all 97 essential embryonic genes targeted , the wddd provides information about embryonic lethality and phenotypic defects that were observed in the injected worms and their progeny .
the wddd is composed of two cross - linked databases : a database of quantitative information about cell division dynamics and a database of information about the rnai experiments .
the database of quantitative information about cell division dynamics , which also contains the 4d dic microscopy images , can be searched based on the name of the open reading frame ( orf ) or gene targeted by the rnai , or based on the accession number of embryo .
search results provide the accession number , orf name , gene name , chromosome number , information about the rnai experiment ( accession number of rnai experiment and link to the information ) , information about recording and measurement systems ( e.g. microscope system , temperature and version of our system ) and the embryonic lethality of the recorded embryo ( figure 2b ) .
links to the wormbase ( 18 ) are available to rapidly obtain information about the gene .
the quantitative information about cell division dynamics and the set of 4d dic microscopy images for each embryo can be downloaded from the search results or viewed in a web browser ( figure 3 ) .
the viewer was implemented with the use of webgl , html5 canvas and javascript . in the viewer ,
focal planes and time points can be changed with arrow keys , and the view angle of the data can be changed by using the mouse to drag - and - move .
synchronous viewing of microscopy images and the related quantitative information enable us to easily understand cell positions , movements and divisions .
figure 3.viewing 4d dic microscopy images and quantitative information about cell division dynamics in a web browser . in this example , four datasets for par genes were found in the wddd and viewed interactively through a web browser .
the time point and focal plane could be changed by using the keyboard , and the view angle could be changed by using the mouse .
the left and right panel in the viewer window show the dic microscopy image and quantitative information about cell division dynamics , respectively .
yellow lines represent outlines of detected nuclear regions , and red points represent centroids of nuclear regions corresponding to each nucleus . viewing 4d dic microscopy images and quantitative information about cell division dynamics in a web browser . in this example , four datasets for par genes were found in the wddd and viewed interactively through a web browser .
the time point and focal plane could be changed by using the keyboard , and the view angle could be changed by using the mouse .
the left and right panel in the viewer window show the dic microscopy image and quantitative information about cell division dynamics , respectively .
yellow lines represent outlines of detected nuclear regions , and red points represent centroids of nuclear regions corresponding to each nucleus .
the database of rnai experiments can also be searched based on the name of the orf or gene targeted by the rnai , or based on the accession number for each independent experiment .
search results provide the accession number , orf name , gene name , primer set used to amplify the templates for dsrna synthesis , detailed information about the rnai method , descriptions of embryonic lethality and other phenotypes observed in the rnai experiment and the information about cell division dynamics obtained from the rnai experiment ( accession number of embryo ) ( figure 2c ) .
these search results contain links to the wormbase to enable the user to obtain the information about the targeted gene and the primer set used to create the dsrna .
the data format consists of two blocks : one provides information about nuclear tracking and the other provides information about outlines of nuclear regions ( figure 1c ) . using the information , we can calculate parameters related to cell division dynamics such as cell position , movement and division .
we aim to obtain five sets of quantitative information about cell division dynamics for each essential embryonic gene in c. elegans .
the current version of the wddd includes only one or two sets of information for most of the genes examined .
we are currently in the process of obtaining five sets of information for each essential embryonic gene not only on chromosome iii but also on the other chromosomes .
we plan to extend the cell stages included in the database . by using our computational method ( 13 ) ,
we can consistently obtain quantitative information from the one - cell stage to the 2024-cell stage from 4d dic microscopy images .
if we can extend the methodology to later stages , the database could be used to understand various other developmental phenomena : e.g. gastrulation , which begins at the 26-cell stage in c. elegans .
we anticipate that the extension of cell stages can be achieved by optimizing the parameters of our computational method .
we are currently performing further computational analyses of the sets of quantitative information stored in the wddd .
for example , we can perform computational phenotypic analysis ( 13 ) , in which we mathematically define and calculate various kinds of phenotypic characters and then statistically compare these characters between wild - type and rnai embryos . because our collection has a feature of four dimensionality , the computational analysis will enable us to screen for 3d spatial and temporal phenotypes that are difficult to identify in manual analysis . using the results of these analyses , we will create a database of rnai - induced phenotypes that can be searched based on phenotype , such as the rnaidb and the phenobank ( 7,19 ) .
in the wddd , we have released a collection of quantitative information about cell division dynamics in wild - type and rnai embryos . because the information is numerically represented , various parameters related to cell division dynamics such as cell positions , movements and divisions can be computationally extracted .
the sets of the information from wild - type embryos enable statistical comparison of cell division dynamics between wild - type and rnai embryos .
the information collection enables us to analyse cell division dynamics by various computational methods such as those using statistical and clustering techniques ( 13,19,20 ) .
the wddd will provide a novel opportunity for computational biologists to develop computational methods to attain novel insights into the molecular mechanisms of animal development .
for instance , the 4d dic microscopy images of early embryos contain various kinds of morphological information , such as that pertaining to the cell membrane and cytoplasm .
such information will enable researchers to analyse many cellular mechanisms such as cytokinesis , and this information can be used by computer scientists to develop new quantitative morphological measures .
moreover , to make access simple for experimental biologists , the 4d dic microscopy images and quantitative information about cell division dynamics can be viewed in a web browser without the use of a special software program .
we released the quantitative information about cell division dynamics in an original format , which is different from the formats used for several other sets of the quantitative information about morphological dynamics ( 12,14 ) .
if the formats of quantitative information about morphological dynamics were unified , computational methods developed to analyse such information could be applied to all sets without modification .
efforts will be made to establish a unified format for quantitative information about morphological dynamics .
systems genomics ; special coordination funds for the promotion of science and technology , from the ministry of education , culture , sports , science and technology of japan .
funding for open access charge : national bioscience database center , japan science and technology agency . | during animal development , cells undergo dynamic changes in position and gene expression .
a collection of quantitative information about morphological dynamics under a wide variety of gene perturbations would provide a rich resource for understanding the molecular mechanisms of development . here
, we created a database , the worm developmental dynamics database ( http://so.qbic.riken.jp/wddd/ ) , which stores a collection of quantitative information about cell division dynamics in early caenorhabditis elegans embryos with single genes silenced by rna - mediated interference .
the information contains the three - dimensional coordinate values of the outlines of nuclear regions and the dynamics of the outlines over time .
the database provides free access to 50 sets of quantitative data for wild - type embryos and 136 sets of quantitative data for rna - mediated interference embryos corresponding to 72 of the 97 essential embryonic genes on chromosome iii .
the database also provides sets of four - dimensional differential interference contrast microscopy images on which the quantitative data were based .
the database will provide a novel opportunity for the development of computational methods to obtain fresh insights into the mechanisms of development .
the quantitative information and microscopy images can be synchronously viewed through a web browser , which is designed for easy access by experimental biologists . |
primary apocrine adenocarcinomas are uncommon malignant cutaneous neoplasms commonly involving the axilla ; however , other sites such as the eyelid , ear , scalp , anogenital region , chest , foot , lip , and breast can be affected .
most of these lesions are indolent with cases of relapse and a high local recurrence rate of 28%
. cases of lymph node , pulmonary as well as bone metastasis have been reported .
there are only a handful of cases describing the cytological features of this neoplasm . here
, we report a case that mimicked tuberculous sinus , clinically , and turned out to be primary apocrine adenocarcinoma on cytology as well as histopathology .
a young male aged 35 years presented to the surgery outpatient department with a swelling in the right axilla for the past 1 year .
the patient denied any history of weight loss , decreased appetite , night sweats , tuberculosis , diabetes , or hypertension .
he was a nonsmoker , nonalcoholic , and had no family history of malignancy . on examination ,
the patient was afebrile with a firm - to - hard swelling in the right axilla .
the swelling was 3 2 cm in size with a sinus discharging pus - like material and pale granulation tissue .
preliminary investigations to rule out tuberculosis were all negative including the mantoux test , sputum for acid - fast bacilli , and chest radiograph .
fine - needle aspiration cytology yielded pus like aspirate and on may - grnwald - giemsa ( mgg ) staining revealed cellular smears , showing atypical epithelial cells arranged in papillary clusters , sheets , and acini with nuclear overcrowding and overlapping [ figure 1a ] .
the cells showed a moderate amount of cytoplasm , high nuclear - cytoplasmic ratio , mild anisonucleosis and hyperchromasia with prominent nucleoli .
the cytoplasm showed apocrine changes at places within the columnar cells [ figure 1b ] .
an impression of a malignant epithelial lesion favoring adenocarcinoma with apocrine and cystic change was made .
( a ) smear shows pleomorphic cells with hyperchromatic nuclei forming papillary and acinar pattern and macrophages in background ( mgg , 400 ) ; ( b ) smear shows a sheet of cells with large nuclei , clumped chromatin , prominent nucleoli , and deep eosinophilic cytoplasm ( mgg , 400 ) ; ( c ) section shows ulcerated epidermis with infiltrating nests and glandular structures present immediately beneath it ( h and e , 40 ) ; ( d ) shows infiltrating glands with decapitated luminal secretions and apocrine change ( h and e , 100 ) ; inset shows cellular details ( h and e 400 ) a subsequent biopsy revealed two grayish brown soft tissue pieces measuring 0.7 cm and 0.9 cm .
the immediate subepidermis and dermis showed infiltration by tumor cells arranged in a glandular pattern with the large cells having a variable amount of cytoplasm .
lumina of some of the glands showed evidence of decapitated apocrine secretions [ figure 1d ] .
the cytoplasm of tumor cells as well as luminal secretions were positive for periodic acid - schiff ( pas ) stain [ figure 2a ] .
immunohistochemically , the tumor cells were strongly positive for pancytokeratin ( panck ) and carcinoembryonic ( cea ) antigen [ figures 2b and c , respectively ] . a final histopathological diagnosis of primary apocrine adenocarcinoma was thus ascertained .
( a ) shows cytoplasmic and luminal secretions positivity ( pas , 400 ) ; ( b ) shows intense cytoplasmic positivity for pan ck ( ihc , 40 ) ; ( c ) shows intense cytoplasmic positivity for cea ( ihc , 400 ) the tumor was excised with a wide surgical margin and the patient was followed up for 6 months without any recurrence .
sweat gland apocrine adenocarcinoma is a rare entity , with only few case reports so far .
those in the fifth to seventh decades of their lives constitute the most common age group of diagnosis .
most neoplasms are slowly progressive , small in size , and are most frequently seen in the axilla .
they can be recurrent and metastasize to the lymph node , lung , and bone .
cytological diagnosis of a primary apocrine adenocarcinoma is difficult as the differential diagnosis always includes metastatic carcinoma , carcinoma arising in ectopic breast tissue , and extramammary paget 's disease .
however , a high suspicion of apocrine adenocarcinoma , as in our case , can prove to be helpful to the surgeon in establishing the patient management plan .
the presence of neoplastic glands high in the dermis and immediate subepidermis favors the primary origin of tumor cells from apocrine sweat glands , as was the case in our patient .
apocrine adenocarcinomas are positive for cytokeratins , carcinoembryogenic antigen ( cea ) and epithelial membrane antigen ( ema ) as well as gross cystic disease fluid protein ( gcdfp ) .
apocrine adenocarcinoma has poor prognosis and the prognostic factors include size , histological type , lymph node involvement , and distant metastasis .
the 10-year disease free survival rate in the absence of metastasis to the lymph nodes is 56% .
the treatment of choice is wide local excision with clear margins , with or without regional lymph node dissection . a broad spectrum of both clinical and pathological
benign axillary lymphadenopathy was the initial clinical diagnosis made in this case , most likely of a tuberculous etiology .
however , the suspicion was ruled out after unpromising investigations . among the malignant disorders , lymphomas could have been considered but were ruled out by a negative personal history of weight loss / malaise / fever and absence of multiple lymphadenopathy or bilaterality .
possibility of male breast cancer or metastatic adenocarcinoma from the lung , prostate , git , etc .
, was also considered initially but the suspicion was ruled out in the absence of any supportive clinicoradiological data . hence , a diagnosis of primary apocrine adenocarcinoma was made in light of the above discussion .
the presentation of primary apocrine adenocarcinoma as an axillary swelling with a discharging sinus is uncommon .
the mean age of presentation has been around 60 years in various case reports but our case was a young male
. initial diagnosis on cytological assessment has been dubious so far in the literature but was quite diagnostic and raised a high suspicion of adenocarcinoma with apocrine change , as in our case .
reporting of such entities enhances the knowledge of its varied presentations , important diagnostic tools , prognostic factors , and further establishment of therapeutic regimes .
| primary apocrine sweat gland adenocarcinomas are a rare entity , with only a few case reports so far .
many of these carcinomas are slow - growing with a high recurrence rate
. a distinct cytological diagnosis can be made , and metastatic adenocarcinomas are always considered as a differential diagnosis on cytology . our case was a 35-year - old male who presented with a discharging axillary sinus and swelling for the past 1 year . a clinical suspicion of tuberculous sinus was raised that however , remained unsupported by laboratory investigations .
there was quite a high suspicion of apocrine adenocarcinoma on cytological examination that was confirmed by histopathology and immunohistochemistry .
the patient was successfully treated with total excision and a wide margin .
we report this case in view of its rarity and its occurrence in a 35-year - old young male , and emphasize that an initial cytological suspicion should be raised for primary apocrine adenocarcinoma in case of an axillary tumor , especially keeping in consideration the poor prognosis of the same and chances of early metastasis . |
a 55-year - old man traveled to mainland china from march 5 to march 15 . by march 18
the patient was given a course of antimicrobial drugs , and the fever resolved . by march 23 ,
at this point , sars was suspected , and the patient was moved into isolation in an intensive care unit the same day and had to be intubated for 5 days .
results from the polymerase chain reaction ( pcr ) test indicated the presence of the sars - associated coronavirus .
the patient had no previous history of serious respiratory illness or any other serious coexisting conditions , and the source of the exposure could not be determined .
the 50-year - old wife of patient 1 was exposed to sars upon her husband 's return on march 15 . on march 23 , a cough developed , and she had shortness of breath and chills .
because sars was suspected , the patient was placed on antiviral treatment , and sars was confirmed by pcr testing .
patient 2 was placed in isolation on a medical ward on march 25 and remained there until april 11 .
the 15-year - old daughter of patients 1 and 2 also became exposed to sars when her father returned on march 15 .
, she complained of stomach pain and , upon examination , had a temperature of 37.7c .
the 23-year - old daughter of patients 1 and 2 , who lived away the family home , became exposed to sars through contact with both patients 1 and 2 upon a brief visit ( lasting < 1 hour ) on march 19 . by march 27
a pcr test was not completed because her fever resolved , and no other symptoms developed .
a 55-year - old man traveled to mainland china from march 5 to march 15 . by march 18
the patient was given a course of antimicrobial drugs , and the fever resolved . by march 23 ,
at this point , sars was suspected , and the patient was moved into isolation in an intensive care unit the same day and had to be intubated for 5 days .
results from the polymerase chain reaction ( pcr ) test indicated the presence of the sars - associated coronavirus .
the patient had no previous history of serious respiratory illness or any other serious coexisting conditions , and the source of the exposure could not be determined .
the 50-year - old wife of patient 1 was exposed to sars upon her husband 's return on march 15 . on march 23 , a cough developed , and she had shortness of breath and chills .
because sars was suspected , the patient was placed on antiviral treatment , and sars was confirmed by pcr testing .
patient 2 was placed in isolation on a medical ward on march 25 and remained there until april 11 .
the 15-year - old daughter of patients 1 and 2 also became exposed to sars when her father returned on march 15 .
, she complained of stomach pain and , upon examination , had a temperature of 37.7c .
the 23-year - old daughter of patients 1 and 2 , who lived away the family home , became exposed to sars through contact with both patients 1 and 2 upon a brief visit ( lasting < 1 hour ) on march 19 . by march 27
a pcr test was not completed because her fever resolved , and no other symptoms developed .
| with cases of severe acute respiratory syndrome ( sars ) occurring across geographic regions , data collection on the effectiveness of intervention strategies should be standardized to facilitate analysis .
we propose a minimum dataset to capture data needed to examine the basic reproduction rate , case status and criteria , symptoms , and outcomes of sars . |
specimens of b. variegata ( n = 12 ) were obtained from a commercial source as captive - bred metamorphs and were raised to maturity in our vivarium for a period of 18 months .
secretions were washed from toads with distilled deionized water , snap frozen in liquid nitrogen , and lyophilized .
a 5-mg sample of lyophilized skin secretion was reconstituted in 0.5 ml of trifluoroacetic acid ( tfa)/water ( 0.1:99.9 , v / v ) , clarified by centrifugation and subjected to liquid chromatography - mass spectrometry ( lc / ms ) using an lcqtm electrospray ion - trap mass spectrometer interfaced with a gradient hplc system ( both supplied by thermofinnegan , san jose , ca , usa ) .
the gradient employed was formed from tfa / water ( 0.1:99.9 , v / v ) to tfa / water / acetonitrile ( 0.1:19.9:80.0 , v / v / v ) in 240 min at a flow rate of 1 ml / min .
fractions were collected at 1-min intervals and the column effluent was continuously monitored at 214 nm .
fractions were stored at 4?c and samples of 100 l were removed , lyophilized , and stored at ?
male adult wistar rats , weighing 200250 g , were killed by asphyxiation with co2 followed by cervical dislocation in accordance with uk animal research legislation .
the animals were laid on their dorsal surfaces , followed by the removal of the tail skin . the tail artery vascular bed was identified and moistened with the krebs solution .
the proximal region of the tail artery was excised and immediately placed in an ice - cold krebs solution .
two - millimeter - wide rings of the artery were cut and mounted on a transducer prior to placing in 2-ml organ baths containing the krebs solution flowing through at 2 ml / min and maintained at 37?c with constant bubbling of a carbogen gas mixture ( 95% o2,/5% co2 ) .
one hundred - microliter samples of sequential reverse phase hplc fractions of b. variegata skin secretion were evaporated to dryness and reconstituted in the same volume of the krebs solution before screening for the bradykinin inhibitory activity .
after the addition of each fraction to a segment of arterial smooth muscle , a second addition of bradykinin ( 10 m ) was added and the relaxation response was recorded .
changes in tension of the artery were detected by pressure transducers connected to a powerlab system ( ad instruments pty ltd . ) . following the identification of the bradykinin inhibitor peptide fraction and determination of its primary structure ,
a synthetic replicate was used to construct an accurate dose - response curve of bradykinin responses within the range 10 to 10 m , with and without pre - treatment with the inhibitory peptide at 10 m. data were analyzed to obtain the mean and standard error of responses by student 's t - test and dose - response curves were constructed using a best - fit algorithm through the data analysis package provided .
responses were plotted as percentages of maximal contraction against final molar concentrations of the peptide present in the organ bath and six replicates were used for each data point .
the primary structure of the novel bradykinin inhibitor peptide was deduced by automated edman degradation using an applied biosystems 491 procise sequencer , following identification by lc / ms .
the molecular mass of the peptide was determined by the interrogation of archived lc / ms data corresponding to the peptide(s ) present in the bradykinin inhibitory fraction .
after these procedures , when the primary structure had been unequivocally established , the purified peptide was synthesized by shanghai biotech bioscience and technology co. , ltd .
a 5-mg sample of the lyophilized skin secretion was dissolved in 1 ml of the cell lysis / mrna protection buffer supplied by dynal biotec ( uk ) .
polyadenylated mrna was isolated by the use of magnetic oligo - dt beads as described by the manufacturer ( dynal biotec ) .
mrna was eluted in 20 l of rnase free water , and first - strand cdna synthesis for subsequent race reactions was performed using a smart - race kit ( clontech , uk ) essentially as described by the manufacturer .
briefly , the race reactions were amplified using a sense primer ( s , 5-gctctgataatgagactgtggttct-3 ) and an antisense primer ( as , 5-gacaccatgtgacataacaatgcttat-3 ) for the ( ala , thr)-bradykinin cdnas by thermostable polymerase ( invitrogen ) . these primers were complementary to a domain of nucleotide sequences in the 5 and 3-untranslated regions of the thr -bradykinin precursor cdna cloned previously from b. orientalis skin tissue .
the pcr cycling procedure was as follows : an initial denaturation step for 1 min at 94c followed by 35 cycles consisting of denaturation for 30 s at 94c , primer annealing for 30 s at 63c and extension for 3 min at 72c .
gel electrophoresis of the pcr products was followed by further purification , cloning using a pgem - t vector system ( promega corporation ) , and subsequent sequencing using an abi 3100 automated capillary sequencer .
specimens of b. variegata ( n = 12 ) were obtained from a commercial source as captive - bred metamorphs and were raised to maturity in our vivarium for a period of 18 months .
secretions were washed from toads with distilled deionized water , snap frozen in liquid nitrogen , and lyophilized .
a 5-mg sample of lyophilized skin secretion was reconstituted in 0.5 ml of trifluoroacetic acid ( tfa)/water ( 0.1:99.9 , v / v ) , clarified by centrifugation and subjected to liquid chromatography - mass spectrometry ( lc / ms ) using an lcqtm electrospray ion - trap mass spectrometer interfaced with a gradient hplc system ( both supplied by thermofinnegan , san jose , ca , usa ) .
the gradient employed was formed from tfa / water ( 0.1:99.9 , v / v ) to tfa / water / acetonitrile ( 0.1:19.9:80.0 , v / v / v ) in 240 min at a flow rate of 1 ml / min .
fractions were collected at 1-min intervals and the column effluent was continuously monitored at 214 nm .
fractions were stored at 4?c and samples of 100 l were removed , lyophilized , and stored at ?
male adult wistar rats , weighing 200250 g , were killed by asphyxiation with co2 followed by cervical dislocation in accordance with uk animal research legislation .
the animals were laid on their dorsal surfaces , followed by the removal of the tail skin . the tail artery vascular bed was identified and moistened with the krebs solution .
the proximal region of the tail artery was excised and immediately placed in an ice - cold krebs solution .
two - millimeter - wide rings of the artery were cut and mounted on a transducer prior to placing in 2-ml organ baths containing the krebs solution flowing through at 2 ml / min and maintained at 37?c with constant bubbling of a carbogen gas mixture ( 95% o2,/5% co2 ) .
one hundred - microliter samples of sequential reverse phase hplc fractions of b. variegata skin secretion were evaporated to dryness and reconstituted in the same volume of the krebs solution before screening for the bradykinin inhibitory activity .
after the addition of each fraction to a segment of arterial smooth muscle , a second addition of bradykinin ( 10 m ) was added and the relaxation response was recorded .
changes in tension of the artery were detected by pressure transducers connected to a powerlab system ( ad instruments pty ltd . ) . following the identification of the bradykinin inhibitor peptide fraction and determination of its primary structure ,
a synthetic replicate was used to construct an accurate dose - response curve of bradykinin responses within the range 10 to 10 m , with and without pre - treatment with the inhibitory peptide at 10 m. data were analyzed to obtain the mean and standard error of responses by student 's t - test and dose - response curves were constructed using a best - fit algorithm through the data analysis package provided .
responses were plotted as percentages of maximal contraction against final molar concentrations of the peptide present in the organ bath and six replicates were used for each data point .
the primary structure of the novel bradykinin inhibitor peptide was deduced by automated edman degradation using an applied biosystems 491 procise sequencer , following identification by lc / ms .
the molecular mass of the peptide was determined by the interrogation of archived lc / ms data corresponding to the peptide(s ) present in the bradykinin inhibitory fraction .
after these procedures , when the primary structure had been unequivocally established , the purified peptide was synthesized by shanghai biotech bioscience and technology co. , ltd .
a 5-mg sample of the lyophilized skin secretion was dissolved in 1 ml of the cell lysis / mrna protection buffer supplied by dynal biotec ( uk ) . polyadenylated mrna was isolated by the use of magnetic oligo - dt beads as described by the manufacturer ( dynal biotec ) .
mrna was eluted in 20 l of rnase free water , and first - strand cdna synthesis for subsequent race reactions was performed using a smart - race kit ( clontech , uk ) essentially as described by the manufacturer .
briefly , the race reactions were amplified using a sense primer ( s , 5-gctctgataatgagactgtggttct-3 ) and an antisense primer ( as , 5-gacaccatgtgacataacaatgcttat-3 ) for the ( ala , thr)-bradykinin cdnas by thermostable polymerase ( invitrogen ) .
these primers were complementary to a domain of nucleotide sequences in the 5 and 3-untranslated regions of the thr -bradykinin precursor cdna cloned previously from b. orientalis skin tissue .
the pcr cycling procedure was as follows : an initial denaturation step for 1 min at 94c followed by 35 cycles consisting of denaturation for 30 s at 94c , primer annealing for 30 s at 63c and extension for 3 min at 72c .
gel electrophoresis of the pcr products was followed by further purification , cloning using a pgem - t vector system ( promega corporation ) , and subsequent sequencing using an abi 3100 automated capillary sequencer .
screening of the reverse phase hplc fractions of b. variegata skin secretion for peptides displaying the bradykinin inhibitory activity resolved a single active fraction no .
electrospray ionization ms analysis of this peptide resolved a series of related multiply - charged ions with a deduced molecular mass of a nonprotonated parent ion of 2300.92 da [ figure 2 ] .
blank cycles at positions 8 , 11 , and 14 were deemed to be due to the presence of cysteinyl residues and the c - terminal cysteinyl residue was predicted based on the computation of molecular mass from sequence and comparison with that derived by ms .
the interrogation of contemporary protein / peptide databases by fasta and blast internet sequence alignment tools indicated that the peptide corresponded exactly to the c - terminal domain of skin kininogen-1 previously cloned from b. variegata skin ( accession number aj320269 ) that also encodes one copy of ( ala , thr)-bradykinin [ figure 3 ] .
the peptide is flanked n - terminally by a typical kr propeptide convertase processing site and the c - terminal kk sequence is removed by posttranslational processing to generate a mature peptide . as a consequence of its structural attributes ,
this peptide was named ic-20 ( n - terminal isoleucine ( i ) , c - terminal cysteine ( c ) and consisting of 20 amino acid residues .
102 that exhibited bradykinin - inhibitory activity ( arrow ) electrospray ionization ( esi ) mass spectrum of peptide ic-20 present in the reverse phase hplc fraction ( mentioned in figure 1 ) .
the doubly charged ( m+2h ) = m / z 1151.51 and triply charged ( m+3h ) = m / z 768.14 ions are predominant nucleotide sequence of bombina variegata skin kininogen-1 encoding a single copy of ( ala , thr)-bradykinin ( dotted underline ) and a single copy of peptide ic-20 ( single underlined ) .
the putative signal peptide is double - underlined and the stop codon is indicated with an asterisk repeated pharmacological experiments using a synthetic replicate of bradykinin showed that , as expected , that this peptide produced a sigmoidal dose response curve in terms of relaxation induction .
however , when the tissue was pretreated with the novel peptide , ic-20 , at the maximal effective concentration of bradykinin ( 1 10 m ) , bradykinin - induced relaxation of the arterial smooth muscle was abolished by 50 - 60% [ figure 4 ] .
this effect was consistent with a noncompetitive mechanism of action as indicated by nonparallel dose
response curves of relaxation effects on a rat tail artery smooth muscle preparation in the presence of bradykinin ( ) or in the presence of bradykinin and peptide ic-20 ( qub2300 ; ) at 10 m .
screening of the reverse phase hplc fractions of b. variegata skin secretion for peptides displaying the bradykinin inhibitory activity resolved a single active fraction no .
electrospray ionization ms analysis of this peptide resolved a series of related multiply - charged ions with a deduced molecular mass of a nonprotonated parent ion of 2300.92 da [ figure 2 ] .
blank cycles at positions 8 , 11 , and 14 were deemed to be due to the presence of cysteinyl residues and the c - terminal cysteinyl residue was predicted based on the computation of molecular mass from sequence and comparison with that derived by ms .
the interrogation of contemporary protein / peptide databases by fasta and blast internet sequence alignment tools indicated that the peptide corresponded exactly to the c - terminal domain of skin kininogen-1 previously cloned from b. variegata skin ( accession number aj320269 ) that also encodes one copy of ( ala , thr)-bradykinin [ figure 3 ] .
the peptide is flanked n - terminally by a typical kr propeptide convertase processing site and the c - terminal kk sequence is removed by posttranslational processing to generate a mature peptide . as a consequence of its structural attributes ,
this peptide was named ic-20 ( n - terminal isoleucine ( i ) , c - terminal cysteine ( c ) and consisting of 20 amino acid residues .
102 that exhibited bradykinin - inhibitory activity ( arrow ) electrospray ionization ( esi ) mass spectrum of peptide ic-20 present in the reverse phase hplc fraction ( mentioned in figure 1 ) .
the doubly charged ( m+2h ) = m / z 1151.51 and triply charged ( m+3h ) = m / z 768.14 ions are predominant nucleotide sequence of bombina variegata skin kininogen-1 encoding a single copy of ( ala , thr)-bradykinin ( dotted underline ) and a single copy of peptide ic-20 ( single underlined ) .
the putative signal peptide is double - underlined and the stop codon is indicated with an asterisk
repeated pharmacological experiments using a synthetic replicate of bradykinin showed that , as expected , that this peptide produced a sigmoidal dose response curve in terms of relaxation induction . however ,
when the tissue was pretreated with the novel peptide , ic-20 , at the maximal effective concentration of bradykinin ( 1 10 m ) , bradykinin - induced relaxation of the arterial smooth muscle was abolished by 50 - 60% [ figure 4 ] .
this effect was consistent with a noncompetitive mechanism of action as indicated by nonparallel dose
response curves of relaxation effects on a rat tail artery smooth muscle preparation in the presence of bradykinin ( ) or in the presence of bradykinin and peptide ic-20 ( qub2300 ; ) at 10 m .
a wide range of bioactive peptides have been identified in defensive secretions and venoms from many different submammalian species that can effectively interact with mammalian targets that include enzymes , ion channels , and g - protein - linked receptors .
these peptides occur as components of complex molecular cocktails and often there are many in a single cocktail that interact with different discrete targets . in venoms , that are primarily directed toward the capture of prey ,
many of these peptides induce biological effects that are lethal to the recipient , whereas in defensive secretions , the biological effects are usually directed toward the arrest of the activity of attacking predators through unpleasant action or debilitation through induction of pain , acute inflammation , edema , and hypotension .
bradykinin - related peptides have received much attention within the last decade , with many novel forms having been identified from a wide range of amphibian defensive skin secretions .
[ 378111213 ] what has become clear is that such amphibian secretions represent a unique resource for the discovery of natural structural variants of the canonical mammalian peptide and that many of these are homologs of forms found in submammalian vertebrates .
the wide range of variants is thought to be due to molecular tailoring of core structures through natural selection to provide the most effective spectrum of agents to deter predation by specific predator groups .
bradykinins are particularly illustrative of this process as each major vertebrate taxon appears to possess discrete molecular variants of this peptide that are reflected in the spectra of brps occurring in the defensive secretions of amphibians . the complex defensive skin secretions of b. variegata have been studied previously in some detail resulting in the identification of several types of bioactive peptides such as broad - spectrum antimicrobials , trypsin inhibitors , bombesins , and prokineticin , in addition to two unusual bradykinin - related peptides , ( ala , thr)-bradykinin and ( val , thr , thr)-bradykinin .
bradykinin antagonist / inhibitor peptides have been found in the defensive skin secretions of b. maxima ( kinestatin ) and b. orientalis ( dv-28 amide ) , and both have been shown to be co - encoded with brps within the structures of discrete skin kininogens .
ic-20 is the first peptide with bradykinin inhibitory effects identified from b. variegata defensive skin secretion and this peptide was , like kinestatin and dv-28 amide , found to be co - encoded with a brp within the structure of a skin kininogen .
this peptide exhibits little primary structural similarity with any known peptide whose structure is archived on contemporary online structure databases and therefore constitutes a novel prototype molecule for further in - depth pharmacological investigations .
bradykinin inhibitors are clearly applicable as possible treatment options for pathological processes such as chronic pain and chronic inflammatory disorders , such as rheumatoid arthritis and inflammatory bowel disease .
allergic asthma has also been linked to an exaggerated and persistent response to bradykinin resulting in bronchospasm . through its autocrine growth factor function
, bradykinin has also been linked as a causative agent in tumor growth and metastasis , by facilitating angiogenesis and promoting the vegf and mmp activity .
thus , the discovery of naturally occuring bradykinin inhibitors with unique structures that may act through novel mechanisms in the blocking of bradykinin signaling could provide the medicinal chemist with a range of potential lead compounds for future drug development programs or could shed new light on the pharmacological mechanisms of bradykinin action . | objectives : the objectives were to determine if the skin secretion of the european yellow - bellied toad ( bombina variegata ) , in common with other related species , contains a bradykinin inhibitor peptide and to isolate and structurally characterize this peptide.materials and methods : lyophilized skin secretion obtained from this toad was subjected to reverse phase hplc fractionation with subsequent bioassay of fractions for antagonism of the bradykinin activity using an isolated rat tail artery smooth muscle preparation .
subsequently , the primary structure of the peptide was established by a combination of microsequencing , mass spectroscopy , and molecular cloning , following which a synthetic replicate was chemically synthesised for bioassay.results:a single peptide of molecular mass 2300.92 da was resolved in hplc fractions of skin secretion and its primary structure determined as iynaiwp - kh - nk - kpgll- .
database interrogation with this sequence indicated that this peptide was encoded by skin kininogen-1 previously cloned from b. variegata .
the blank cycles were occupied by cysteinyl ( c ) residues and the peptide was located toward the c - terminus of the skin kininogen , and flanked n - terminally by a classical kr- propeptide convertase processing site .
the peptide was named ic-20 in accordance ( i = n - terminal isoleucine , c = c - terminal cysteine , 20 = number of residues ) . like the natural peptide
, its synthetic replicate displayed an antagonism of bradykinin - induced arterial smooth muscle relaxation.conclusion:ic-20 represents a novel bradykinin antagonizing peptide from amphibian skin secretions and is the third such peptide found to be co - encoded with bradykinins within skin kininogens . |
pc12 cells were transiently transfected using lipofectamine 2000 ( invitrogen ) ( 1:3 dna to lipofectamine ratio ) , with gfp - fused wt or mutated syns or with gfp - containing control vector ; the quantity of dna was chosen according to previously reported data , as the syn expression level was low and comparable to the average physiological levels of the protein in the brain .
after sds - page , proteins were transferred onto polyvinylidene difluoride membranes and immunostained with the following antibodies : anti- tubulin mouse igg ( clone b-512 , sigma - aldrich ) ; anti - tyrosinated tubulin mouse igg ( clone tub-1a2 , sigma - aldrich ) .
immunostaining was revealed by enhanced chemiluminescence super - signal west pico chemiluminescent , pierce ) .
quantification was performed by image j software ( nih ) and subtracting the background around bands .
transfected pc12 cells were fixed with cold methanol ( 6 min at 20c ) ; to remove unassembled tubulin , before fixation , some slides were extracted in pem buffer ( 80 mm k - pipes , 5 mm egta , 1 mm mgcl2 , ph 6.8 , containing protease inhibitors ) with 0.5% triton x-100 , 0.2 m nacl and 10 m paclitaxel ( sigma - aldrich ) .
pc12 cells were stained with anti- tubulin mouse igg or anti - tyrosinated tubulin mouse igg and alexa fluor 568 donkey anti - mouse . by using image j software , total fluorescence intensity
the region of interest was manually drowned and the analyses of the surface extension revealed that there were no significant differences between control cultures and wt - expressing pc12 cells ( data not shown ) .
pc12 cells were transiently transfected using lipofectamine 2000 ( invitrogen ) ( 1:3 dna to lipofectamine ratio ) , with gfp - fused wt or mutated syns or with gfp - containing control vector ; the quantity of dna was chosen according to previously reported data , as the syn expression level was low and comparable to the average physiological levels of the protein in the brain .
after sds - page , proteins were transferred onto polyvinylidene difluoride membranes and immunostained with the following antibodies : anti- tubulin mouse igg ( clone b-512 , sigma - aldrich ) ; anti - tyrosinated tubulin mouse igg ( clone tub-1a2 , sigma - aldrich ) .
immunostaining was revealed by enhanced chemiluminescence super - signal west pico chemiluminescent , pierce ) .
quantification was performed by image j software ( nih ) and subtracting the background around bands .
transfected pc12 cells were fixed with cold methanol ( 6 min at 20c ) ; to remove unassembled tubulin , before fixation , some slides were extracted in pem buffer ( 80 mm k - pipes , 5 mm egta , 1 mm mgcl2 , ph 6.8 , containing protease inhibitors ) with 0.5% triton x-100 , 0.2 m nacl and 10 m paclitaxel ( sigma - aldrich ) .
pc12 cells were stained with anti- tubulin mouse igg or anti - tyrosinated tubulin mouse igg and alexa fluor 568 donkey anti - mouse . by using image j software , total fluorescence intensity
the region of interest was manually drowned and the analyses of the surface extension revealed that there were no significant differences between control cultures and wt - expressing pc12 cells ( data not shown ) .
the authors are grateful to all the members of the lab and to all the people which contribute in delineating the syn functions .
this work was supported by fondazione grigioni per il morbo di parkinson , milan , italy [ to g.c . ] ; dote ricerca , | abstractthe partitioning between tubulin dimers and microtubules is fundamental for the regulation of several neuronal activities , from neuronal polarization and processes extension to growth cone remodelling .
this phenomenon is modulated by several proteins , including the well - known microtubule destabilizer stathmin .
we recently demonstrated that -synuclein , a presynaptic protein associated to parkinson 's disease , shares structural and functional properties with stathmin , and we showed that -synuclein acts as a foldable dynamase . here , we pinpoint the impact of wild type -synuclein on the partitioning between tubulin dimers and microtubules and show that parkinson 's disease - linked mutants lose this capability .
thus , our results indicate a new role for -synuclein in regulating microtubule system and support the concept that microtubules and -synuclein are partners in the modulation of neuronal health and degenerative processes .
furthermore , these data strengthen our hypothesis of the existence of a functional redundancy between -synuclein and stathmin . |
no man is an island entire of itself ( john donne ) . with the assembly of proteins into functional complexes thought to underlie most , if not all , biological processes , characterization of these structures is a key goal in cell biology .
an initial step is identification of complex members , both stably- and transiently - associated , and their intra - complex interactions .
the current method of choice for interactome analyses is affinity purification followed by mass spectrometry ( ap - ms ; for review see [ 1 - 3 ] ) , and the development of quantitative methods has enabled resolution of the components of large multiprotein complexes and provided information about their stoichiometry [ 4 - 7 ] . what this type of approach on its own does not provide , however , is information about the topological structure of the complex and the functional significance of each member .
furthermore , it traditionally involves breaking open cells to extract complexes for analysis , a process that can be disruptive to the underlying protein - protein associations .
bioid is a recently developed technique that complements traditional ap / ms - based interactome mapping by highlighting intracellular protein
it was inspired by the damid method utilized to detect dna - protein interactions via methylation of dna sequences proximal to a dna binding protein fused to dam methylase . in the bioid approach , a promiscuous prokaryotic biotin protein ligase ( bira * )
is fused to the protein of interest . when expressed in cells , the fusion protein will biotinylate proteins with which it comes into close proximity , such as direct binding partners and neighbouring proteins in multiprotein complexes ( fig .
importantly , it has the ability to capture both stable interactions and transient or weak interactions .
biotinylated proteins can be isolated by affinity purification , using a streptavidin agarose matrix , and identified by ms .
caveats include the inability to distinguish direct vs. indirect interactors ( similar to ap / ms ) and the unknown activity radius of bira * , which would define the resolution of this technique . as an initial non - biased screen for in vivo associations , however , a major strength is the accessibility of this method to a wide range of researchers , in that it requires only standard molecular and cell biology techniques and access to proteomics services .
a. in the bioid approach , fusion of a promiscuous e. coli biotin protein ligase ( bira * ) to the protein of interest promotes biotinylation of near - neighbour proteins in vivo .
these biotinylated proteins can then be captured by affinity purification and identified by mass spectrometry . b. the combination of cross - linking with mass spectrometry
complexes ( either in vivo or affinity purified ) are treated with a bi - functional cross - linking reagent that creates a covalent link between adjacent regions of polypeptide chains .
these links can be intra - chain ( within the same protein ; green ) or inter - chain ( within neighbouring proteins ; red ) .
proteolytic digests are then analyzed by lc - ms / ms to identify cross - linked peptides , which in turn provide structural information about the protein complexes . c. a non - radioactive translation - controlled pulse - chase system that enables spatiotemporal monitoring of the biogenesis of multiprotein compexes .
left panel : cells transformed with a plasmid encoding the gene of interest ( with a c - terminal affinity tag ) downstream of an ha tag and amber stop codon ( uag ) only synthesize the ha peptide due to translational termination at this premature stop codon .
middle panel : co - expression of an engineered orthogonal pair of amber suppressor trna and trna - synthetase allows incorporation of the unnatural amino acid o - methyl tyrosine ( ome - tyr ) and suppression of the uag stop codon , leading to expression of the full ha - protein - affinity tag construct .
addition of ome - tyr to the media thus induces a translational pulse of tagged protein expression .
right panel : due to a tetracycline - regulatable riboswitch engineered into the 5 ' utr of the ha - uag - gene - affinity tag plasmid , synthesis can then be inhibited at any time by addition of tetracycline ( translational chase ) .
affinity purification of the tagged protein and interactome mapping at different time points following the pulse can be used to probe changes in complex composition .
higher resolution probing of the topology of multiprotein complexes , both in vitro and in vivo , has been enabled by the coupling of classic chemical cross - linking techniques with recent advances in mass spectrometer instrumentation , proteomic methodologies and bioinformatics ( for review see [ 10 - 13 ] ) .
cross - linking provides proximity information , revealing not only which proteins are getting cross - linked but also at which sites the cross - linking takes place ( fig . 1b ) .
the combination of cross - linking with mass spectrometry has been utilized , both on its own and in combination with other structural analysis methods to probe the architecture of complexes such as ribosomes , proteasomes , rna polymerase ii
although challenges for cross - linking / ms include the low abundance of cross - linked peptides and the complexity of the fragmentation spectra , these are being addressed by the development of more efficient , affinity tag - linked cross - linking reagents and more powerful data analysis and quantitation software . incorporating quantitative measurements further extends the ability of this approach to analyze the dynamic assembly / disassembly and functional composition of multiprotein complexes .
the biological importance of the assembly order of multiprotein complexes was recently demonstrated by the analysis of evolutionary gene fusion events in a large number of species , which revealed that protein complexes are under evolutionary selection to assemble via ordered pathways .
mapping a dynamic assembly process using proteomic approaches requires sufficient temporal resolution , which can be provided by a recently developed protein translation - controlled pulse - chase system ( fig . 1c ; ) . in this approach ,
a pulse of de novo synthesis of a tagged protein is followed by a time course of affinity purification and interactome mapping to reveal dynamic changes in the composition of complexes to which it is targeted .
cells are transformed both with a plasmid encoding the gene of interest ( flanked by n- and c - terminal affinity tags ) with an in - frame amber stop codon ( uag ) inserted just after the n - terminal tag , and with a plasmid encoding an engineered orthogonal pair of amber suppressor trna and trna synthetase . in the absence of ome - tyr
, only the n - terminal tag is synthesized because translation halts at the uag ( fig .
addition of ome - tyr to the media allows cells to incorporate this unnatural amino acid at the uag , leading to translation of the full - length fusion protein .
a tc - apta riboswitch engineered into the 5 ' end of the transcript allows the pulse of de novo protein expression to be rapidly shut down upon addition of tetracycline , which binds the riboswitch and interferes with translation initiation . although this pulse - chase method was developed in yeast , incorporation of unnatural amino acids via orthogonal amber suppressor trna / trna synthetase pairs ( for review see ) extends its use to other biological systems , including drosophila and mammalian cells , highlighting the potentially broad applicability of this technique for the spatiotemporal analysis of multiprotein complex assembly .
valuable clues to the physiological function of a protein can be obtained by observing the downstream phenotypic effects of removing it from cells or organisms ( fig .
at the dna level , powerful knockout and mutagenesis approaches based on homologous recombination and zinc finger nucleases have enabled targeted deletion / mutation of specific genes in model systems , including yeast , mammalian cells and mice ( for review see [ 25 - 27 ] ) . at the rna level , post - transcriptional gene silencing techniques based on rna interference ( rnai ; for review see ) permit the knockdown of specific proteins via targeted degradation of their mrna .
a caveat to these approaches is that both lie upstream of the protein itself , incorporated within its functional multiprotein complex(es ) , and thus necessitate a time delay until protein levels are reduced ( which will vary based on protein turnover rates ) or limit studies into the effects of permanent removal of the protein .
a. functional studies have traditionally relied on disruption of the protein of interest at the level of the gene or mrna transcript .
one drawback to this is the lack of real time information , i.e. the immediate effects of the removal of that protein .
the genetically encoded degradfp targets an f - box domain ( nsimb ) to gfp fusion proteins via a single domain anti - gfp nanobody ( vhhgfp4 ) .
association of the f - box domain with endogenous scf ( skp1/cul1/f - box ) protein ligase complexes leads to ubiquitination and subsequent proteasome - mediated degradation of the fusion protein .
c. inducible , reversible degradation of proteins mediated by a plant auxin - inducible degron ( aid ) .
fusion of aid to the gene of interest and co - expression of the plant f - box protein tir1 facilitates rapid , inducible degradation of the fusion protein upon addition of the auxin hormone indole-3-acetic acid ( iaa ) , as tir1 binds and is incorporated into endogenous scf complexes .
inclusion of a gfp tag provides localization information and the ability to monitor protein loss in live cells .
in contrast , targeted destruction offers the ability to study the acute effects of the immediate removal of a protein .
one in vivo approach is the spatially and temporally defined photo - ablation method chromophore - assisted light inactivation ( cali ; for review see ) , in which the target protein is fused to a fluorophore , such as killerred , that produces substantial amounts of reactive oxygen species ( ros ) upon absorption of light at a particular wavelength .
the end result is destruction of the target protein in the region of interest , although caveats include inadvertent protein cross - linking and inactivation of proteins beyond the immediate target by diffusion of the ros .
alternative in vivo methods that take advantage of the endogenous ubiquitin - mediated protein degradation pathway have been developed , and two recent protein knockout techniques , based on the skp1/cul1/f - box ( scf ) protein ubiquitin ligase complex , extend both the in vivo applicability and time resolution of this type of approach . by fusing an f - box protein derived from drosophila ( slmb ) with a single - domain antibody fragment ( vhhgfp4 ) that recognizes green fluorescent protein ( gfp ) and related derivatives , caussinus and colleagues created a genetically encoded method , which they call degradfp , that enables the direct depletion of target proteins fused to these fluorophores .
recruitment of endogenous scf complex members by slmb leads to ubiquitination of the fusion protein and its targeted degradation by the proteasome ( fig .
although a major strength of this approach is its potential applicability to any gfp - tagged construct , the authors noted the failure of degradfp to induce degradation of both free gfp and a particular protein incorporated into adherens junctions . while this suggests possible structural and accessibility limitations , it will be easier to judge the extent and implications of this as the technique is applied to a wider range of substrates .
auxin - induced degradation , based on a unique ligand - induced degradation pathway in plants , is a related approach that can further increase the time resolution of protein depletion and is fully reversible . in this system ,
a target protein is expressed as a fusion with an auxin - inducible degron ( aid ) in cells that also exogenously express the plant f - box protein transport inhibitor response 1 ( tir1 ) .
auxin hormones such as indole-3-acetic acid ( iaa ) promote the interaction between aid - containing proteins and tir1 , which can in turn recruit endogenous scf proteins and promote ubiquitination and proteasome - mediated degradation of the target protein ( fig . 2c ) .
depletion is thus inducible , rapid and complete , and fully reversible upon removal of iaa . in this study ,
the authors demonstrate targeted depletion of a wide range of substrates localized to different regions of mammalian cells , including nucleosomal histones , centrosome- , centromere- and telomere - associated proteins and cytoplasmic cyclin b1 .
degradation could be readily monitored by fluorescence imaging , due to an additional gfp ( or related derivative ) tag added to the fusion proteins . as with any fusion protein , the addition of tags ( in this case 25 kda aid plus 27 kda gfp ) has the potential to affect localization and function , and thus proper in vivo behavior must first be demonstrated .
furthermore , a limitation of both degradfp and aid - induced degradation is that they can not control the stability of endogenous untagged proteins .
the continued refinement of homologous recombination strategies in various model systems does , however , offer the potential to extend these technologies by genetically encoding the tags in frame with endogenous genes .
taken together , these novel methods for dissecting multiprotein complexes in vivo offer unprecedented sensitivity and spatiotemporal resolution , which is a large step toward the ultimate goal of mapping functional multiprotein complexes throughout the cell under a variety of conditions .
importantly , most do not require specialized knowledge or equipment and are therefore accessible to a wide range of researchers .
they can also be adapted to different model systems and further modified to increase their resolution and applicability .
| the current consensus is that the majority of proteins act in concert in the cell , as homo- and heteromeric complexes of two or more proteins that carry out discrete biological functions . a wide range of genomic , proteomic , biochemical , structural and biophotonic techniques have been employed over the years to study the protein - protein interactions that define complexes , with the end goal of producing a spatiotemporal map of these modular functional units throughout the cell .
recent advances in the analysis of in vivo complexes have greatly improved structural , functional and temporal resolution , and this review highlights novel approaches ranging from proximity - dependent labeling and cross - linking / mass spectrometry through pulse - chase epitope labeling and targeted protein degradation . |
several types of microorganisms reside in the intestine and comprise an individual 's microbial flora .
probiotic microorganisms serve various purposes , such as increasing beneficial bacteria - growth , promoting digestion and absorption , and suppressing infectious diseases .
the human immune system performs activities of innate immunity , otherwise known as the nonspecific immune system that functions as the body 's first line of defense , and adaptive immunity , referred to as the acquired immune system or the specific immune system .
natural killer ( nk ) cells are innate lymphoid cells that play a role in natural immunity against tumors and infected cells .
nk cell numbers decrease because of various reasons , such as aging , stress , and smoking cigarettes.6 , 7 thus , it is worthwhile to investigate whether functional foods or the bioactive components of certain foods can improve nk cell activity .
recently , probiotic organisms , such as lactobacillus , have been shown to have several functional properties , including stimulation of the immune system .
the mechanism of nk cell activation by lactobacillus is thought to involve increased production of several cytokines following macrophage phagocytosis of lactobacillus .
the gut brain - microbiota axis is increasingly recognized as an important regulator of intestinal physiology .
microbial flora affect postnatal development of the hpa stress response in mice , and germ - free mice exhibit more anxiety than their conventional counterparts .
these findings suggest that the modulation of intestinal microbiota , through probiotics or symbiotics , could alter human behavior and reduce stress . however , there are limited number of clinical trials that have investigated effects of probiotics on both the immune system and stress - induced disorders
. there are currently three lactobacillus biotope classifications : vegetable lactobacillus , animal lactobacillus , and intestinal lactobacillus .
it was recently reported that vegetable lactobacillus isolated from vegetarians ' intestines activates immune functions and prevents infection and cancer .
in addition , vegetable lactobacillus contains plant - derived antibacterial agents , including tannins , and can persist in high - salt and low - ph environments .
lactobacillus plantarum hokkaido ( hokkaido strain ) was isolated from well - pickled vegetables in hokkaido , japan , by the hokkaido food processing research center .
this strain is resistant to salt , alcohol , and ph , protects individuals who consume it from bacterial infection , regulates intestinal functions , and improves isoflavone absorption . regarding immune regulation , it was reported that coincubation of the hokkaido strain with human dendritic cell lines increased interleukin ( il)-12 mrna expression .
in addition , the hokkaido strain induced the production of il-8 , a neutrophil chemotactic factor , in human monocytes ( htp-1 ) and osc70 epithelial cells .
these reports demonstrate that the hokkaido strain activates nk cells and likely improves immune function .
these findings warranted a clinical trial to determine whether yogurt containing the hokkaido strain improves immune function and decreases stress markers .
however , very few clinical studies have been conducted to specifically assess responses to the hokkaido strain .
here we evaluated whether ingestion of hokkaido strain yogurt improves immune activity and decreases stress markers in japanese adults .
the composition of the hokkaido strain yogurt investigated in this study is presented in table 1 . the production and packing of test meals
subjects were instructed to ingest daily 90 g of yogurt containing l. plantarum hokkaido ( 5.0 10 cfu , hokkaido strain yogurt ) or yogurt fermented with lactobacillus delbrueckii subsp .
hansen , hoersholm , denmark ) without hokkaido strain ( placebo-1 ) or a yogurt - like dessert without the hokkaido strain ( placebo-2 ) .
the hokkaido strain was originally isolated from well - pickled vegetables in hokkaido , japan , by the hokkaido research organization . in this study ,
171 subjects ( 28 males and 143 females , age range 3169 years ) with nk cell activity below 50% were enrolled .
subjects with a recent history of gastrointestinal disorders , pregnancy , significant disease , surgery , severe allergic reaction to food , or current use of any medication were excluded .
mean subject age , body weight ( bw ) , height , body mass index ( bmi ) , body fat percentage , and nk cell activity for each group are reported in table 2 .
the clinical intervention was conducted as a double - blind , placebo - controlled trial . at randomization ,
the 171 eligible subjects were randomly assigned to one of the three groups ( hokkaido strain yogurt group , placebo-1 group , and placebo-2 group ) with adjustment for age , sex , and nk cell activity . the time schedule for this clinical study is shown in fig . 1
. we performed hematological examinations and body composition ( bw , bmi , and body fat percentage ) measurements at baseline ( week 0 ) and post - intervention ( weeks 4 and 8) for the three groups .
each subject 's body compositionwas measured with an in - body device ( biospace co. , tokyo , japan ) .
all subjects provided written informed consent before undergoing any study - related tests , and the study protocol was approved by the ethics committee of hokkaido information university .
the study protocol conformed to the helsinki declaration and was registered at the umin clinical trial registration system ( certificate number umin000014138 ) .
changes in subject values were analyzed using student 's t - tests comparing means between the test group and placebo-1 group or between the test group and placebo-2 group .
statistical analyses were performed using spss statistic 19 ( ibm , armonk , ny , usa ) .
there were no significant differences among the three study groups in age , height , bw , bmi , body fat percentage , or nk cell activity at baseline ( table 2 ) . to determine the effect of hokkaido strain yogurt on immune activity , we evaluated nk cell activity ( fig .
there was no significant difference between the test group and placebo-1 group or between the test group and placebo-2 group .
next , to clarify the effects of age on response , we divided the 171 subjects into subgroups with respect to median age : younger subjects ( < 50 years ; n = 86 ) and older subjects ( 50 years ; n = 85 ) . for the older subjects
, there was no significant difference among the three study groups ( fig . 2c ) . in the younger subjects ,
however , the nk cell activity of the test group increased significantly compared with that of the placebo-1 group at 8 weeks ( placebo-1 : 3.04% 13.87% ; hokkaido strain yogurt : 3.40% 9.58% , reported as the change in the percentage of nk cell activity from baseline to 8 weeks , p = 0.043 ) ( fig .
although no significant between - group differences were observed in serum monocyte , eosinophil , and basophil ratio ( fig .
3c e ) , neutrophils were significantly decreased in the hokkaido strain yogurt group compared with the placebo-2 group ( fig .
3a ) ( placebo-2 : 1.98% 9.07% ; hokkaido strain yogurt : 0.93% 5.21% , reported as the change in the percentage of neutrophil from baseline to 8 weeks , p = 0.038 ) .
in addition , lymphocytes were slightly increased at 8 weeks following the ingestion of hokkaido strain yogurt ( fig .
3b ) ( placebo-2 : 1.47% 8.00% ; hokkaido strain yogurt : 0.63% 4.47% , reported as the change in the percentage of lymphocyte from baseline to 8 weeks , p = 0.087 ) .
neutrophil - to - lymphocyte ratio ( nlr ) and serum cortisol are commonly used as stress - induced biomarkers .
the hokkaido strain yogurt intake group showed a slight decrease in nlr compared with the placebo-2 intake group at 8 weeks ( fig .
4a ) ( placebo-2 : 0.05 0.84 ; hokkaido strain yogurt : 0.09 0.52 , reported as the change in the rate of nlr from baseline to 8 weeks , p = 0.093 ) .
in addition , serum cortisol was suppressed by intake of the hokkaido strain yogurt compared with the placebo-2 group , but only marginally
( fig . 4b ) ( placebo-2 : 0.29 2.21 g / dl ; hokkaido strain yogurt : 0.25 2.6 g / dl , reported as the change in serum cortisol level from baseline to 8 weeks , p = 0.236 ) .
we examined the levels of several biomarkers of blood metabolism , lipid and glucose metabolism , and body composition . in the hokkaido strain yogurt group
, minimal changes were observed in the parameters of lipid metabolism ( total cholesterol , low - density lipoprotein cholesterol , high - density lipoprotein cholesterol , and triglyceride ) and glucose metabolism ( fasting plasma glucose and hemoglobin a1c ) , as well as body composition ( bw , bmi , and body fat percentage ) as shown in table 3 .
these results suggest that the ingestion of hokkaido strain yogurt has no or minimal unfavorable effects on these parameters even at the dose of 90 g / day .
the results of our randomized , double - blind , placebo - controlled , parallel - group clinical study indicate the potential effects of the hokkaido strain yogurt on stress and immune activity . although no significant differences in nk cell activity were observed , the younger subjects ( < 50 years ) in the hokkaido strain yogurt group showed increased nk cell activity compared with those in the placebo yogurt group . in addition , the trends of decreased neutrophil and nlr were observed in the hokkaido strain yogurt group when compared with yogurt - like dessert ( placebo-2 ) group .
therefore , the potential effects of hokkaido strain yogurt include improved immune function and stress reduction .
we observed no statistically significant differences in the percentage change in nk cell activity among the three study groups when evaluated in all age subjects .
however , the percentage change in nk cell activity increased in the younger subjects ( < 50 years ) of the hokkaido strain yogurt group compared with the placebo-1 group at study week 8
. there have been various reports on the influence of age on nk cell activity .
conversely , krishnaraj et al . suggested that nk cell activity increases with aging .
moreover , delarosa et al . suggested that overall nk cell activity was unchanged with age because individual cell activity decreased , but cell numbers increased . in our clinical study ,
initial nk cell values were widely varied in subjects over 50 years old compared with subjects less than 50 years old .
this fact might influence the lack of change in nk cell activity with diet change in the older cohort .
this possibility requires further investigation to determine how hokkaido strain yogurt ingestion increased nk cell activity in the younger subjects .
moreover , the initial percentage of nk cell activity at baseline was correlated strongly with the percentage change in nk cell activity at week 8 ( pearson correlation coefficient : 0.379 , p = 0.01 ) , but no differences were observed between the overall groups .
these results imply that the increase of nk cell activity in the hokkaido strain yogurt group could be the result of a low initial percentage of nk cell activity in the hokkaido strain yogurt group compared with the placebo-1 group .
further investigation is required to evaluate the effects of hokkaido strain yogurt on nk cell activity . in our clinical study , neutrophils were significantly decreased in the hokkaido strain yogurt group compared with the placebo-2 group . in addition , lymphocytes were slightly increased at week 8 following ingestion of the hokkaido strain yogurt . moreover
, the hokkaido strain yogurt group showed a slightly decreased nlr compared with the placebo-2 group at week 8 .
serum cortisol increases the neutrophil half - life and induces neutrophil release from myeloid or splenic neutrophil pools to the blood .
moreover , the states of sympathetic dominance increase nlr , which is the reason why adrenalin facilitates an increase in neutrophil proliferation through binding to the adrenalin receptors expressed by neutrophils . in addition , it was reported that patients with alzheimer 's disease had high nlrs compared with healthy subjects , and that nlr was correlated with beta amyloid deposition .
these findings suggest that the hokkaido strain yogurt exerts both anti - stress and anti - inflammatory effects . in a stressful environment
for example , increasing adrenocorticotropic hormone by exposure to an acute stressor was higher in germ - free mice than control mice in vivo .
moreover , ingestion of probiotics significantly improved depressed mood and the degree of conscious stress in a human trial . in our clinical study ,
serum cortisol was more suppressed in the hokkaido group than the placebo-2 group , although this suppression was not significant .
cortisol has been used in many studies as an indicator of the hpa axis stress response , which is activated by exposure to an acute stressor .
these findings may suggest that the mechanism of l. plantarum hokkaido in hokkaido strain yogurt reduction in stress is through hpa via regulation of intestinal flora , resulting in a decrease in stress markers , nlr , and serum cortisol .
in addition , it was reported that mental stress and nk cell activity are closely related .
nk cell activity in students declined on the day of examinations compared with 1 month before examinations , suggesting that mental stress decreases nk cell activity . in our clinical study ,
nlr improved more in < 50-year - old subjects ( p = 0.079 , data not shown ) , which indicated that improvement of nk cell activity and nlr was correlated with hokkaido strain ingestion .
this possibility requires further investigation to clarify the effects of the hokkaido strain yogurt on stress relief in subjects who are subject to daily stressors .
in our clinical study , the younger subjects ( < 50 years ) in the hokkaido strain yogurt group showed increased nk cell activity compared with those in the placebo yogurt group .
neutrophils were decreased in subjects who ingested hokkaido strain yogurt compared with those who ingested the yogurt - like dessert .
in addition , nlr , which is associated with stress , trended lower in the hokkaido strain yogurt group compared with the yogurt - like dessert group . in conclusion
this research was supported in part by the northern advancement center for science and technology ( noastec ) foundation .
| lactobacillus plantarum hokkaido ( hokkaido strain ) was isolated from well - pickled vegetables in hokkaido , japan .
we report a randomized , double - blind , placebo - controlled study evaluating the effects of l. plantarum hokkaido on immune function and stress markers in 171 adult subjects .
subjects were divided into three groups : the l. plantarum hokkaido yogurt group , the placebo-1 group who ingested yogurt without the hokkaido strain , and the placebo-2 group who ingested a yogurt - like dessert without the hokkaido strain .
hematological tests and body composition measurements were performed before and after 4 and 8 weeks of blinded ingestion . although no significant differences in natural killer cell activity were observed , it was found that neutrophil ratio significantly decreased and lymphocytes tended to increase in the hokkaido strain yogurt group compared with the yogurt - like dessert group .
in addition , the neutrophil - to - lymphocyte ratio , a stress marker , tended to improve in the hokkaido strain yogurt group compared with the yogurt - like dessert group .
these results suggest that the ingestion of hokkaido strain yogurt tends to improve immune activity and decrease stress markers . |
patients are categorized based on clinical acuity in the emergency departments ( eds ) so the more critically - ill patient is , the more immediate treatment and care needs .
the canadian triage and acuity scale ( ctas ) is a five - level emergency department triage algorithm that has been continuously developed in canada and subjected to several studies .
the ctas , a descriptive 5-point triage scale , has been approved by the canadian association of emergency physicians , the national emergency nurses affiliation , the canadian pediatric society and the society of rural physicians of canada .
the ctas is based on a comprehensive list of patients ' complaints is used to ascertain the triage level .
several studies have investigated the validity and reliability of the ctas in adult and pediatric populations ; but it 's still unclear to what extent the ctas would support consistency in triage nurses ' decision making in canada comparing to other countries , considering the wide variety of health care systems around the world . besides , some studies have addressed contextual influences on the triage decision making process , therefore it is necessary to discover the impact of these variables on the reliability of triage scale .
however some studies reported moderate consistency for ctas , it needs to be more explored in terms of participants , statistics , instruments and other influencing criteria as well as mistriage .
the reliability of triage scales should be assessed by internal consistency , repeatability and inter - rater agreement .
however , kappa has been the most commonly used statistics to measure inter - rater agreement , so it is worth - mentioning that kappa statistics could be influenced by incidence , bias and levels of scale lead to misleading results .
it is reported that weighted kappa statistics could reveal high and deceiving reliability coefficients . therefore computing a pooled estimate of a reliability coefficient could help us identify significant differences among reliability methods .
meta - analysis is a systematic approach for introduction , evaluation , synthesis and unifying results in relation to studying research questions .
it also produces the strongest evidence for intervention . therefore ; it is an appropriate method to gain comprehensive and deep insight into the reliability of triage scale especially in regard to kappa statistics .
a review on reliability of the ctas demonstrated that kappa ranges from 0.202 ( fair ) to 0.84 ( almost perfect ) .
the considerable variation in the kappa statistics indicates a real gap in the reliability of triage scale .
so in view of the methodological limitations of the triage scale reliability , context - based triage decision making and the necessity of comprehensive insight into scale reliability in the eds , the aim of this study was to provide a meta - analytic review of the reliability of the ctas in order to examine to what extent the ctas is reliable .
the university research ethics committee approved the study . in the first phase of the study , a literature search was conducted through investigating cinahl , scopus , medline , pubmed , google scholar and cochrane library databases until the 1 march 2014 .
meta - analysis has been performed from jan to july 2014 and authors started to collect data from march 2014 .
triage , system , scale , agreement , emergency and canadian triage and acuity scale [ appendix a ] .
relevant citations in reference lists of final studies were hand - searched to identify additional articles regarding the reliability of ctas .
two researchers independently examined the search results in order to recover potentially eligible articles [ figure 1 ] .
irrelevant article has been defined as article which was not related in any manner to the canadian triage and acuity scale or did n't contain reliability coefficient .
articles have been chosen according to the guidelines for reporting reliability and agreement studies ( grras ) . according to the guidelines , only those studies that had reported description for sample size
, number of raters and subjects , sampling method , rating process , statistical analysis and reliability coefficients were included in the analysis .
qualified paper was defined as a paper with qualifying score > 6 out of the 8 criteria .
the articles in which the type of reliability was not reported were excluded from the analyses .
researchers also recorded moderator variables such as participants , raters , origin and publication year of study . in the next phase , participants ( age - group , size ) ,
raters ( profession , size ) , instruments ( live , scenario ) , origin and publication year of study , reliability coefficient and method were retrieved .
reliability coefficients were extracted from articles as below :
- inter - rater reliability : kappa coefficient ( weighted and un - weighted ) , intraclass correlation coefficient , pearson correlation coefficient and spearman rank correlation coefficient.- intra - rater reliability : articles which contained reliability statistics including pearson correlation coefficient , intraclass correlation coefficient and spearman rank correlation coefficient were included.- internal consistency : articles that reported alpha coefficients were included in the analyses .
- inter - rater reliability : kappa coefficient ( weighted and un - weighted ) , intraclass correlation coefficient , pearson correlation coefficient and spearman rank correlation coefficient .
- intra - rater reliability : articles which contained reliability statistics including pearson correlation coefficient , intraclass correlation coefficient and spearman rank correlation coefficient were included .
- internal consistency : articles that reported alpha coefficients were included in the analyses . in meta - regression , each sample was considered as a unit of analysis .
if the same sample were reported in more than two articles , it was included once .
in contrast , if several samples regarding different populations were reported in one study , each sample was separately included as a unit of analysis .
the most qualified articles reported reliability coefficient using kappa statistics , so it could be considered as an r type of coefficient ranging from 1.00 to + 1.00 .
standard agreement definition was used as poor ( = 0.00 - 0.20 ) , fair ( = 0.21 - 0.40 ) , moderate ( = 0.41 - 0.60 ) , substantial ( = 0.61 - 0.80 ) , and almost perfect ( = 0.81 - 1.00 ) .
kappa could be treated as a correlation coefficient in meta - analysis . in order to obtain the correct interpretation , back - transformation ( z to r transformation ) of pooled effect sizes to the level of primary coefficients
simple meta - regression analysis was performed according to method of moments estimator . in the meta - regression model ,
effect size as dependent variable , and studies and subject characteristics as independent variable were considered to discover potential predictors of reliability coefficients .
z - transformed reliability coefficients are regressed on the following variables : origin and publication year of study .
distance was defined as distance from origin of each study to origin of ctas ( new brunswick , canada ) .
meta - regression was performed using a random effects model because of the presence of significant between - study variation .
search strategy introduced 339 primary citations relevant to the reliability of ctas . finally , fourteen unique citations emerged ( 4.12% out of 339 ) which met the inclusion criteria [ figure 1 ] .
subgroups were organized regarding participants ( adult / pediatric ) , raters ( nurse , physician , expert ) and method of reliability ( intra / inter rater ) , reliability statistics ( weighted / un - weighted kappa ) and origin and publication year of study .
a. m. has over 10 years of experience in triage and m. e. as an expert , is the head of triage committee in the university .
two clinicians ( a. m. and m. e. ) and one statistician ( r. m. ) have reviewed all articles independently .
thirty percent of all studies have been conducted using the latest version of triage scale after 2008 .
inter - rater reliability had been used in all studies except for one study using intra - rater reliability .
no study in our analysis used alpha coefficient to report internal consistency in reliability analysis .
weighted kappa coefficient was the most common statistics [ table 1 ] . overall pooled coefficient for the ctas was substantial 0.672 ( ci 95% : 0.599 - 0.735 ) .
pooled estimates of participants ' reliability coefficients ( random effects model ) studies on reliability of ctas participants ' pooled coefficients ranged from substantial 0.651 ( ci 95% : 0.402 - 0.811 ) for nurse - expert agreement , 0.670 ( ci 95% : 0.073 - 0.913 ) for physician - physician agreement , 0.721 ( ci 95% : 0.630 - 0.793 ) for nurse - nurse agreement to almost perfect 0.800 ( ci 95% : 0.774 - 0.823 ) for nurse - physician agreement [ figure 3 ] .
fisher 's z transformed pooled estimates of participants ' reliability ( random effects model ) ( ne = nurse - expert , nn = nursenurse , np = nurse - physician , pp = physician - physician ) agreement regarding adult and pediatric version of the ctas was substantial 0.746 ( ci 95% : 0.675 - 0.804 ) for adult and 0.598 ( ci 95% : 0.375 - 0.714 ) for pediatrics .
agreement regarding paper - based scenario assessment was substantial 0.698 ( ci 95% : 0.620 - 0.762 ) while it was almost perfect 0.900 ( ci 95% : 0.875 - 0.920 ) for real live cases assessment .
agreement regarding inter - rater and intra - rater reliability was substantial 0.708 ( ci 95% : 0.629 - 0.773 ) and almost perfect 0.800 ( ci 95% : 0.773 - 0.824 ) respectively .
agreement relating to weighted kappa was substantial 0.714 ( ci 95% : 0.639 - 0.775 ) and also moderate 0.475 ( ci 95% : 0.127 - 0.389 ) for un - weighted kappa .
also agreement regarding most updated version was substantial 0.621 ( ci 95% : 0.446 - 0.751 ) and 0.742 ( ci 95% : 0.655 - 0.811 ) for prior version .
eight studies have reported ( 5 5 ) contingency table to show frequency distribution of triage decisions upon each ctas level between two raters [ table 2 ] .
agreement for each ctas level was ctas l-1 ( 18.14% ) , ctas l-2 ( 7.63% ) , ctas l-3 ( 7.90% ) , ctas l-4 ( 9.18% ) , ctas l-5 ( 14.33% ) and disagreement was ( 5.80% ) , ( 7.89% ) , ( 12.84% ) , ( 12.54% ) , ( 3.76% ) respectively .
mistriage decisions were ( 42.82% ) , of which overtriage was ( 25.52% ) and undertriage ( 17.30% ) [ table 2 ] .
the contingency table of triage decision distribution relating to each ctas category among ed raters meta - regression analysis based on the method of moments for moderators ( distance and publication year ) was performed .
studies in terms of the distance from the origin of the ctas in canada significantly showed lower pooled coefficients , in other terms studies did indicate higher pooled coefficients for the nearest places rather than farther places ( b = 0.00003 ; seb = 0.00000 ; p = 0.0000 ) .
analysis of studies in terms of publication year of study revealed insignificant increase in reliability pooled coefficients , so the reliability of ctas has not been increased systematically through the years ( b = 0.00005 ; seb = 0.00187 ; p = 0.9700 ) .
the ctas showed acceptable level of reliability to guarantee decisions were made consistently regarding allocating patients to appropriate categories .
but generally it 's worth - mentioning that there is a considerable gap between research and clinical practice even at the best of times .
in addition , most studies used weighted kappa statistics to report reliability coefficient [ table 1 ] and the fact that weighted kappa statistics overestimates the reliability of triage scale make it necessary to interpret the results with extreme caution .
so probably it 's important to bear in mind that the ctas reliability is actually at the moderate level which is congruent with several studies .
a calculated 42.82% triage decisions were recognized as mistriage . however ( 25.52% ) of them as overtriage decisions are clinically plausible and could extenuate disagreement among raters in favor of patients , an alarming issue is that ( 13.69% ) of triage decisions is related to undertriage in level i and ii that it 's notable to endanger critically - ill patients life [ table 2 ] .
post - hoc analysis revealed that level iii has been predominant among dong et al . , gravel et al . ,
in spite of the fact that ( 15.21% ) of patients have been assigned into level i has been recognized as notable case - mix of patients in the emergency department , it can not be concluded that ctas has a tendency toward prioritizing patients into level i because only three studies are congruent with combined result .
however esi has tendency towards categorizing patients as level 2 ( 23.39% of all ) , ctas has appropriately distributed patients among triage levels . in fact
, the ctas appropriately distribute patients into triage categories , so it has not a tendency to allocate patients into any specific level . therefore it guarantees to prevent influx of patients in specific category
. this influx could create significant disturbance in patient flow in the eds and causes other parts of ed to remain unusable . comparing to other triage scales , mistriage in esi ( 10.93% ) is notably lower than ctas and agreement among raters ( 78.56% ) is higher than ctas .
the ctas show diverse pooled reliability coefficients regarding participants , patients , raters , reliability method and statistics .
results demonstrated agreement upon adult version and among nurse - physician were higher than pediatrics version and the other groups of raters , respectively .
only sweden has reported reliability studies on ctas except canada [ table 1 ] . in this way
, metaregression showed there is a significant difference in terms of distance from origin of ctas .
it shows that ctas has reached lower reliability coefficients in farther countries [ table 3 ] .
one reason refers to complaint - based nature of ctas that could be translated changeably in routine practice comparing to the canada .
this result is opposed to esi triage scale generalizability which has shown the esi triage scale could be adopted successfully in other countries in spite of cultural diversities .
meta - regression of fisher 's z - transformed kappa coefficients on predictor variables ( studies with weighted kappa ) the third edition of ctas has been released and the reliability of triage scales has not been significantly improved through the years indicating revisions had considerably been effective .
therefore , the ctas could be enhanced through the years and shown improved reliability [ figure 4 ] .
fisher 's z - transformed kappa coefficients in relation to the publication year of study in general , intra - rater reliability is more satisfactory than inter - rater reliability , so it revealed almost perfect agreement comparing to substantial agreement for inter - rater reliability . while intra and inter rater reliability are intended to report the degree to which measurements taken by the same and different observers are similar , respectively ; other methods of examining reliability
has remained uncommon in studies regarding the triage reliability . weighted kappa coefficient showed substantial agreement .
in fact , weighted kappa coefficient revealed higher reliability than un - weighted kappa coefficient because it put more emphasis on the large differences between ratings than to small differences .
thus it 's worth - mentioning even one category difference in allocating patients into appropriate category could endanger clinical outcomes of critically - ill patients .
none of these studies have reported raw agreement for each individual ctas level and only few studies have presented contingency table for inter - rater agreement between raters . since this study is limited to overall reliability , some inconsistencies may exist across each ctas level , therefore the results should be interpreted with caution .
overall , the ctas triage scale showed acceptable level of reliability in the emergency department , also it appropriately distributes patients into triage categories .
therefore it needs more development to reach almost perfect agreement and decrease disagreement especially undertriage .
the reliability of triage scales requires a more comprehensive approach including all aspects of reliability assessment , so it 's necessary to conduct further studies concentrating on the reliability of triage scales , especially in different countries .
| background : although the canadian triage and acuity scale ( ctas ) have been developed since two decades ago , the reliability of the ctas has not been questioned comparing to moderating variable.aims:the study was to provide a meta - analytic review of the reliability of the ctas in order to reveal to what extent the ctas is reliable.materials and methods : electronic databases were searched to march 2014 .
only studies were included that had reported samples size , reliability coefficients , adequate description of the ctas reliability assessment .
the guidelines for reporting reliability and agreement studies ( grras ) were used .
two reviewers independently examined abstracts and extracted data .
the effect size was obtained by the z - transformation of reliability coefficients .
data were pooled with random - effects models and meta - regression was done based on method of moments estimator.results:fourteen studies were included .
pooled coefficient for the ctas was substantial 0.672 ( ci 95% : 0.599 - 0.735 ) .
mistriage is less than 50% .
agreement upon the adult version , among nurse - physician and near countries is higher than pediatrics version , other raters and farther countries , respectively.conclusion:the ctas showed acceptable level of overall reliability in the emergency department but need more development to reach almost perfect agreement . |
general adverse reactions to iodinated radiocontrast media ( rcm ) are divided into immediate ( occurring within 1 hour of administration ) and delayed reactions ( occurring from 1 hour to 1 week after administration).1 - 4 ) immediate hypersensitivity reactions are usually anaphylactoid reactions that range from rashes and a sensation of flushing to life - threatening severe reactions,1 - 4 ) while delayed reactions are predominantly exanthematous skin reactions that are self - limiting.1)3)5)6 ) non - cardiogenic pulmonary edema ( ncpe ) following intravascular injection of rcm is rare .
furthermore , all reported cases of ncpe associated with non - ionic rcm were immediate reactions .
herein , we report a rare case of ncpe presenting as a delayed - type manifestation with a review of the literature .
a 56-year - old male was admitted to the outpatient clinic with a 6-day history of chest pain on exertion lasting for over 10 minutes per episode .
the patient has been treated for hypertension and diabetes mellitus at our hospital since 2009 .
he had no history of allergies . on admission , his blood pressure and pulse rate were 95/55 mm hg and 70 bpm , respectively .
the electrocardiogram showed st - segment elevation with q - wave formation in ii , iii , and avf , and reciprocal st - segment depression in i , avl , and v 4 - 6 ( fig .
his troponin - t level was elevated to 3.03 ng / ml ( reference range : 0 - 0.100 ng / ml ) , while creatine kinase - mb was within the normal limit .
echocardiography showed hypokinesia from the base to the mid - inferior wall with preserved left ventricle ( lv ) systolic function ( ejection fraction=56% by biplane modified simpson 's formula ) .
coronary angiography demonstrated a critical stenosis in the mid right coronary artery ( rca ) with thrombolysis in myocardial infarction grade i flow ( fig .
he underwent stent placement ( a 4.018 mm everolimus - eluting stent ) in the mid rca ( fig .
the patient was given 200 ml of iopamidol ( isovue-300 , dongkook pharmaceuticals , seoul , korea ) , a non - ionic , low osmolar ( 616 mosm / kg water ) rcm .
about 3 hours after the procedure , he developed a fever of above 38. however , the patient was not experiencing a rash , itching , angioedema , rales or wheezing in the lung field .
the patient did not complain of any other symptoms , such as dyspnea , and his vital signs were stable .
the next day , high fever persisted and the patient started to complain of mild dyspnea .
arterial blood gas analysis revealed a ph of 7.436 , a pco2 of 30.2 mm hg , a po2 of 75.9 mm hg , and an oxygen saturation of 95.7% , while receiving nasal cannula oxygen at a flow rate of 5 l / min .
the patient 's white blood cell count was 9400/mm , but eosinophil levels were not raised .
follow - up echocardiography revealed preserved lv systolic function without interval change , in comparison with the initial study .
we did not perform invasive hemodynamic monitoring of swan - ganz catheterization or central line insertion . at first
, we dealt the patient 's condition as cardiogenic pulmonary edema due to fluid or osmolar overload .
however , he was still febrile ( up to 40 ) and pulmonary edema became progressively worse despite negative volume balance ( fig .
subsequently , the patient was diagnosed with ncpe manifesting as a delayed reaction to rcm despite some limitations , such as the absence of eosinophilia and pulmonary wedge pressure monitoring .
we cut his dosage of diuretics and discontinued antibiotic treatment after 48 hours when all of his cultures were negative .
the patient 's fever stopped and the pulmonary edema started to improve one day after the initiation of steroid injection ( fig .
the patient was discharged from the hospital 7 days after the index procedure with complete recovery from pulmonary edema ( fig .
today , non - ionic , low osmolar rcm such as non - ionic monomer : iohexol ( omnipaque ) , iopamidol ( isovue ) , ioversol ( optiray ) and non - ionic dimer : iodixanol ( visipaque , iso - osmolar to plasma , 290 mosm / kg water ) are widely used , while ionic rcm are hardly available in clinical practice .
non - ionic rcm significantly lowers the risk of mild to moderate adverse reactions compared to ionic rcm .
mild to moderate immediate reactions have been reported in 3.8% to 12.7% of patients receiving ionic monomeric rcm and in 0.7% to 3.1% of patients receiving non - ionic rcm.1)3)4 ) severe immediate reactions , such as anaphylaxis and severe hemodynamic compromise , have been reported in 0.16% and 0.03% of patients with ionic and non - ionic rcm , respectively.1)3)4 ) in general , more severe hypersensitivity reactions to rcm manifest as immediate anaphylactic reactions.2)4 ) the onset of immediate reactions is very rapid , with about 70% occurring within 5 minutes after injection and 96% of severe or fatal reactions such as anaphylactic shock , severe angioedema , pulmonary edema , and cardiac arrest occurring within 20 minutes after injection.1 ) there are commonly recommended pretreatment protocols for immediate severe allergic reactions to rcm.4 ) it is also common to use an iso - osmolar agent , iodixanol , for purported safety , especially in the cardiac catheterization laboratory , even though a higher incidence of delayed skin reactions have been reported compared to low osmolar monomers.3)4 ) on the other hand , the most representative delayed adverse reaction is exanthematous skin eruption .
such exanthemas have been reported to affect 1% to 3% of rcm - exposed patients and are usually mild to moderate in severity and self - limiting within 7 days , showing recovery in up to 75% of those affected within 3 days.1)5 - 8 ) prophylaxis is generally not recommended.1)5 - 7 ) non - cardiogenic pulmonary edema caused by non - ionic rcm is rare . only a few reports on ncpe caused by both ionic and non - ionic rcm have been published .
moreover , they all were immediate reactions.9 - 13 ) although systemic symptoms with more immediate - type manifestations such as hypotension , dyspnea , abdominal pain and fever have been occasionally reported,1)8)14 ) a late - onset ncpe , such as our case has not yet been reported .
such pulmonary edema could be caused by mediator release and complement activation resulting in endothelial damage or by a direct irritant effect of the drug on the lungs.12 ) the primary emergency treatment is oxygen with continuous positive airway pressure , or invasive ventilation with positive end expiratory pressure.15 ) treatment of anaphylaxis was not beneficial and diuretics should be given with caution.12 ) corticosteroids can be given to prevent or decrease the severity of the reaction , but should not be expected to be of immediate benefit.4 ) in conclusion , we experienced a rare case of ncpe of a delayed - type hypersensitivity reaction following non - ionic rcm exposure
. it is important for clinicians to be aware of this entity , as manifestation can be quite unusual and life - threatening , and to distinguish the condition from cardiogenic pulmonary edema . | non - cardiogenic pulmonary edema ( ncpe ) is a rare adverse reaction to iodinated radiocontrast media ( rcm ) , in which all previous cases were immediate reactions .
a 56-year - old male was given iopamidol , a non - ionic , low osmolar rcm , during coronary artery angiography .
he developed pulmonary edema and fever a day after the procedure . despite diuretic therapy , the patient 's pulmonary edema worsened and his high fever persisted .
the patient 's pulmonary edema was eventually resolved with intravenous steroid treatment .
we interpreted the patient 's condition as ncpe manifesting as a delayed reaction to rcm . to our knowledge
, our case is the first to show ncpe as a delayed hypersensitivity reaction . |
aneurysms arising from the proximal part of the internal carotid artery ( ica ) between its exit from the proximal dural ring ( oculomotor membrane ) and proximal to the origin of the posterior communicating artery have been collectively termed paraclinoid aneurysms18,19,21 ) .
these paraclinoid aneurysms are classified based on complex relationships between the aneurysm sac , dura , branching arteries , and anterior clinoid process2,3,8,14,18,19,28,29 ) .
advancements in endovascular and microsurgical techniques have substantially improved the completeness of aneurysm sac obliteration operations and the treatment outcomes of paraclinoid aneurysms5,8,9,15,16,18,30,33,35,39 ) . however , because of the incredibly complex neuroanatomical relationship between bone , neural , and vascular structures around this paraclinoid area evidenced by high rates of surgical morbidity and mortality , direct microsurgical occlusion for large and giant paraclinoid aneurysms have remained a great challenge for vascular neurosurgeons .
additionally , in spite of recent endovascular technique improvements , large and giant aneurysms at this specific site often occlude incompletely or recur due to neck broadness33,34 ) .
literature on the surgical results of large aneurysms in this unique anatomical area is limited5,7,9,18,22,30,32,35,39 ) . in this study
, we reviewed our consecutive experiences in the direct surgical clipping of large and giant paraclinoid aneurysms , particularly special surgical techniques , surgery related complications , and outcomes .
a retrospective chart analysis of ten consecutive patients surgically treated for large and giant paraclinoid ica aneurysms , performed by a single neurosurgeon between september 2001 and february 2012 , was performed .
all patients with large paraclinoid aneurysms were female ( mean age , 50.1 years ) .
demographic information for each patient was gathered from medical charts , surgical videos , and pre- and postoperative images .
initial clinical states and postoperative results were assessed by the glasgow coma scale and the glasgow outcome scale .
all patients underwent preoperative three - dimensional ( 3-d ) cerebral computed tomographic ( ct ) angiography and/or digital subtraction angiography ( dsa ) to determine the size , location , and exact configuration of their aneurysms . during angiography ,
balloon test occlusion ( bto ) of the icas and hypotensive challenge tests were performed in five unruptured aneurysm cases in order to assess the cerebrovascular collateral reserve prior to surgery .
however , only 3-d ct angiography was used in the five ruptured aneurysm cases preoperatively .
cervical icas were exposed in all cases for proximal control . according to the aneurysm sac size , direction and the relationship between the position of proximal neck and the distal dural ring ( ddr ) , the tailored orbito - zygomatic approach ( oza )
the authors adopted the supraorbital and subtemporal modified ozas to lower the approach related morbidity . the anterior clinoid process ( acp )
was removed extradurally and intradurally with microrongeurs and 2-mm high - speed diamond burr drill ( midas high - speed surgical drill ; medtronic , minneapolis , mn , usa ) .
the sphenoid ridge was flattened with a high - speed diamond - burr drill or various sized micro - rongeurs until the lateral edge of the superior orbital fissure ( sof ) was reached . the orbitotemporal periosteal fold ( otpf )
was then peeled away from the anterior wall of the cavernous sinus ( cs ) and orbital apex .
this maneuver was the key part of the procedure , as it facilitated dural elevation in the posteromedial direction along the lateral aspect of the acp . through this procedure ,
the roof of the optic canal and most of the optic strut was removed for adequate exposure of the proximal necks of aneurysms and for intracranial proximal control of the ica .
removal was performed intradurally with microrongeurs in most cases to avoid thermal injury of neurovascular structures .
, effort was made to avoid optic nerve injury with minimal and brief traction of the nerve .
aneurysm sacs were decompressed and dissected using aspiration with direct puncture after proximal and distal temporary occlusion .
internal carotid artery reconstruction was performed routinely using a multiple tandem clipping technique with variously shaped fenestrated clips .
briefly , the short right angled fenestrated clip was first applied to the proximal end of the broad - neck aneurysm .
the blades of fenestrated clips were applied in a parallel fashion to the ica for reconstruction of the vessel lumen .
intraoperative doppler was used to confirm no occlusion of perforators at the final step of operation .
the motor evoked potential ( mep ) , somatosensory evoked potential and visual evoked potential ( vep ) were measured using an intraoperative monitoring ( iom ) system ( nim - eclipse system ; medtronic , minneapolis , mn , usa ) in the five unruptured aneurysm cases .
the efficacy of surgical clipping was evaluated with postoperative 3-d dsa and ct angiography in all cases .
postoperative results ( i.e. , clinical outcomes and surgery - related complications ) were evaluated immediately following surgery , at discharge , and at the last follow - up date .
five aneurysms were located in the carotid cave , two in the superior hypophyseal artery , two in the cs , and one in the posterior wall .
the mean aneurysm sac diameter was 18.8 mm in the greatest dimension ( table 1 ) .
initial clinical manifestation included bleeding ( n=5 ) , headache ( n=2 ) , decreased visual acuity ( n=2 ) , and cavernous sinus syndrome ( n=1 ) .
clinical symptoms relating to cs syndrome were caused by neural compression from large intracavernous sinus ica aneurysm sac .
the preoperative clinical neurological conditions and postoperative surgical outcomes were good in most cases ( table 1 ) .
postoperative dsa was also performed to detect any residual aneurysm and the completeness of the aneurysm neck occlusion after clipping .
three cases had multiple aneurysms at other sites ; two patients had two associated unruptured aneurysms [ one had ipsilateral unruptured multiple middle cerebral artery ( mca ) aneurysms , another had contralateral ica dorsal wall and m1 aneurysms ] .
all associated aneurysms had been also treated with surgical clipping simultaneously or through a staged operation ( table 1 , 2 ) . with the exception of one intracavenous aneurysm ,
all large paraclinoid aneurysms were completely obliterated with the ica reconstruction technique using multiple clipping with multiple fenestrated clips without bypass .
immediate surgical complications , which mainly related to ocular symptoms , occurred in five patients .
transient ptosis and hemiparesis occurred in three patients ( 33.3% ) , and recovered spontaneously . at follow - ups of at least six months
, permanent visual complications had remained in two cases ( 20% ) : one case of unilateral blindness and the other of an inferior nasal field defect on the ipsilateral side ( table 2 ) . a 27-year - old female presented with sudden loss of vision on the left side .
on neuro - ophthalmologic examination , visual acuity measured as 0.1 on the right eye by snellen 's chart , but there was total blindness on the left
an aneurysm was measured just over 60 mm in diameter in its greatest dimension ( fig .
exposure of cervical ica , intradural and extradural clinoidectomy with resection of ddr was performed routinely via oza .
the non - thrombosed giant aneurysm was directly clipped and the entire length of the supraclinoid ica was reconstructed with eight different types of fenestrated aneurysm clips . the distal flow through the anterior cerebral artery and middle cerebral artery was nicely preserved ( fig .
however , it resolved two days later with hypervolemic and hypertensive therapy . postoperatively , her right eye vision had not changed , but her left eye vision improved to a level that she could perceive hand movement 30 cm in front of her . a 57-year - old woman presented with a one month history of blurred vision in her left eye
. she had a 14-year history of hypertension for which she had been prescribed antihypertensive medication .
on neuro - ophthalmologic examination , visual acuity measured as 0.9 on both sides by snellen 's chart , and no defects in visual fields or extraocular movements were noted . an unruptured left carotid cave aneurysm measuring 1210 mm
prior to planning surgical clipping , collateral circulation tolerance was confirmed with bto during the preoperative dsa .
the cervical ica was exposed for proximal control and oza with anterior clinoidectomy , and resection of the ddr was performed as part of a routine procedure to expose the proximal neck of the aneurysm .
the intraoperative mep and vep were also monitored . during the tandem clipping and reconstruction of the aneurysm ,
ten minutes after proximal temporary occlusion of the cervical ica , the amplitude of the mep had completely dissipated .
however , ten more minutes of proximal cervical ica temporary occlusion was needed for complete occlusion of the broad aneurysm neck .
four differently shaped fenestrated and two standard clips were used to reconstruct the ica with preservation of the ophthalmic and posterior communicating arteries ( fig .
after re - opening the proximal cervical ica temporary occlusion , the mep amplitude had recovered to one - third of normal at the end of surgery .
the patient displayed right hemiparesis ( grade iii ) immediately after the operation , but her motor weakness gradually recovered and normalized within six hours after surgery .
a 27-year - old female presented with sudden loss of vision on the left side .
on neuro - ophthalmologic examination , visual acuity measured as 0.1 on the right eye by snellen 's chart , but there was total blindness on the left .
an aneurysm was measured just over 60 mm in diameter in its greatest dimension ( fig .
exposure of cervical ica , intradural and extradural clinoidectomy with resection of ddr was performed routinely via oza .
the non - thrombosed giant aneurysm was directly clipped and the entire length of the supraclinoid ica was reconstructed with eight different types of fenestrated aneurysm clips . the distal flow through the anterior cerebral artery and middle cerebral artery was nicely preserved ( fig .
postoperatively , her right eye vision had not changed , but her left eye vision improved to a level that she could perceive hand movement 30 cm in front of her .
a 57-year - old woman presented with a one month history of blurred vision in her left eye .
she had a 14-year history of hypertension for which she had been prescribed antihypertensive medication .
on neuro - ophthalmologic examination , visual acuity measured as 0.9 on both sides by snellen 's chart , and no defects in visual fields or extraocular movements were noted . an unruptured left carotid cave aneurysm measuring 1210 mm
prior to planning surgical clipping , collateral circulation tolerance was confirmed with bto during the preoperative dsa .
the cervical ica was exposed for proximal control and oza with anterior clinoidectomy , and resection of the ddr was performed as part of a routine procedure to expose the proximal neck of the aneurysm .
the intraoperative mep and vep were also monitored . during the tandem clipping and reconstruction of the aneurysm ,
ten minutes after proximal temporary occlusion of the cervical ica , the amplitude of the mep had completely dissipated .
however , ten more minutes of proximal cervical ica temporary occlusion was needed for complete occlusion of the broad aneurysm neck .
four differently shaped fenestrated and two standard clips were used to reconstruct the ica with preservation of the ophthalmic and posterior communicating arteries ( fig .
2e - h ) . after re - opening the proximal cervical ica temporary occlusion ,
the mep amplitude had recovered to one - third of normal at the end of surgery .
the patient displayed right hemiparesis ( grade iii ) immediately after the operation , but her motor weakness gradually recovered and normalized within six hours after surgery .
a 27-year - old female presented with sudden loss of vision on the left side .
on neuro - ophthalmologic examination , visual acuity measured as 0.1 on the right eye by snellen 's chart , but there was total blindness on the left .
an aneurysm was measured just over 60 mm in diameter in its greatest dimension ( fig .
exposure of cervical ica , intradural and extradural clinoidectomy with resection of ddr was performed routinely via oza .
the non - thrombosed giant aneurysm was directly clipped and the entire length of the supraclinoid ica was reconstructed with eight different types of fenestrated aneurysm clips . the distal flow through the anterior cerebral artery and middle cerebral artery was nicely preserved ( fig .
postoperatively , her right eye vision had not changed , but her left eye vision improved to a level that she could perceive hand movement 30 cm in front of her .
a 57-year - old woman presented with a one month history of blurred vision in her left eye .
she had a 14-year history of hypertension for which she had been prescribed antihypertensive medication .
on neuro - ophthalmologic examination , visual acuity measured as 0.9 on both sides by snellen 's chart , and no defects in visual fields or extraocular movements were noted . an unruptured left carotid cave aneurysm measuring 1210 mm
prior to planning surgical clipping , collateral circulation tolerance was confirmed with bto during the preoperative dsa .
the cervical ica was exposed for proximal control and oza with anterior clinoidectomy , and resection of the ddr was performed as part of a routine procedure to expose the proximal neck of the aneurysm .
the intraoperative mep and vep were also monitored . during the tandem clipping and reconstruction of the aneurysm ,
ten minutes after proximal temporary occlusion of the cervical ica , the amplitude of the mep had completely dissipated .
however , ten more minutes of proximal cervical ica temporary occlusion was needed for complete occlusion of the broad aneurysm neck .
four differently shaped fenestrated and two standard clips were used to reconstruct the ica with preservation of the ophthalmic and posterior communicating arteries ( fig .
after re - opening the proximal cervical ica temporary occlusion , the mep amplitude had recovered to one - third of normal at the end of surgery .
the patient displayed right hemiparesis ( grade iii ) immediately after the operation , but her motor weakness gradually recovered and normalized within six hours after surgery .
although endovascular techniques have improved , treatment of large and giant aneurysms in the paraclinoid region remain a significant problem as they are often incompletely treated or recur because of their broad necks , recanalization , and regrowth33,34 ) .
the use of endovascular therapy in the treatment of large paraclinoid aneurysms is limited due to the superiority of the microsurgical treatment , which allows for greater durability , increased ability to ablate an associated mass effect , and decreased cost .
microsurgery of large / giant broad - neck paraclinoid aneurysms is the preferred method of treatment5,9,18,22,35 ) . because of the complex topographic anatomical relationships between aneurysms arising from the proximal ica , branching vessels , and surrounding duro - osseous structures , various terms are used for aneurysm classification1 - 3,8,14,18 - 20,28 - 30,38 ) .
aneurysms in this area can be intradural , extradural , or both and there is also no reliable radiographic method to determine this12,13,25 ) .
the complex surgical anatomy , along with several factors including the size and projection of the lesion , choice of the surgical approach , relationships between the aneurysm and perforator vessels , site of proximal control , and potential improvement or worsening of visual symptoms , account for surgical difficulties5,7,9,19,22,31,35 ) . an accurate preoperative assessment of the origin of these aneurysms is a critical initial step in management .
having accurate microsurgical knowledge about the dural relationships of the paraclinoid region is essential to successful surgical clipping of paraclinoid aneurysms .
it is also important to gain maximal exposure of the aneurysm proximal neck , establish proximal control , and completely obliterate the aneurysms with minimal manipulation of the optic nerve .
. additionally , those operations must be very comfortable and facile with optic strut removal , which is critical for aneurysm proximal neck exposure in most paraclinoid cases .
second , exposure of the cervical ica is an important and useful method for proximal ica control .
third , to avoid optic nerve injury , the pia vessels of the optic nerve must not be disrupted when incising the dura , and retraction of the optic nerve should be brief and minimal .
furthermore , the ophthalmic and superior hypophyseal arteries must be identified before incision of the distal dural ring to avoid inadvertent injury .
the data in our study differed somewhat from what has been shown previously in the literature1,2,5,7,11,15 - 17,26,30 ) in terms of sex ( all females in our study ) , a large number of large and giant aneurysms ( 10/31 , 32.3% ) , and a predominance of carotid cave aneurysms ( 50% ) .
however , certain features including age ( typically diverse in adults , mean age of 50.1 years in our study ) , a presenting symptom of bleeding ( 50% ) , and the incidence of multiple aneurysms ( 3/10 , 30% ) in our study were in line with what has been published previously1,2,5,7,9,10,15 - 17,22,26,30 ) .
the complete removal of the acp , optic canal and strut is an essential step in maximizing proximal neck exposure of large paraclinoid aneurysms and in gaining proximal control of the intracranial ica .
one drawback of the extradural anterior clinoidectomy technique is the limited extent of elevation of the frontotemporal dura over the acp10 ) .
bleeding from the diploic veins or the venous plexus surrounding the clinoid segment of the ica can also make the last step of anterior clinoidectomy difficult .
several authors have recently described incision of the otpf at the level of the lateral edge of the sof as a key step in increasing exposure of the acp , thus facilitating extradural clinoidectomy6,10,27,37 ) .
bone removal techniques using high - speed drills often result in direct mechanical or thermal injury4,36 ) .
since having experienced a case of ipsilateral blindness in intracavernous large aneurysm clipping , we have mainly used microrongeurs or micro kerrison punches when removing the optic canal and optic strut to avoid these surgery - related complications .
chang4 ) reported 45 consecutive anterior clinodectomy cases with a " no - drill " technique with no procedure - related complications in a cranial - based approach to paraclinoid and parasellar lesions .
the greatest hazards relating to the surgical procedure in direct surgical clipping of large / giant paraclinoid aneurysms are microanatomical complexity and restrictions arising from limited space of intracranial proximal control , difficult bone work , broad aneurysm necks , and a lack of comprehensive anatomical knowledge , specifically of 3d contours between the aneurysm and the clinoid ica .
proximal control is another important issue to consider and may be achieved in the cervical carotid artery or the clinoid ica .
we always exposed the common , internal , and external carotid arteries in the neck before performing the craniotomy , and have not favored temporary balloon occlusion or suction maneuvers .
we propose that exposure of the carotid artery in the neck is a much safer procedure as a means of gaining early proximal control . during surgery
, exposure of the clinoid ica and its use as a site of temporary clipping or of proximal control of an unexpected intraoperative rupture of aneurysm can not always be readily achieved .
special recommended clipping techniques to preserve perforators , minimize optic nerve injury , and to achieve complete obliteration of the broad neck of large / giant paraclinoid aneurysms are as follows .
first , short right - angled fenestrated clips which have an aperture larger than the diameter of ica should be used firstly .
second , the short blade , large - aperture fenestrated clips should be applied in a parallel tandem fashion to reconstruct the lumen of the ica without damaging the branching vessels .
third , the use of multiple fenestrated clips with short blades is better than the use of a single long blade clip for reliably and completely occluding broad neck large paraclinoid aneurysms .
five patients had transient or permanent postoperative neurological deficits ( 20% ruptured vs. 75% unruptured aneurysms ) .
the common deficits were visual impairment ( 20% ) and transient motor weakness ( 20% ) .
there were no cases of operative mortality in patients harboring large / giant paraclinoid aneurysms in our series .
a recent study has published an overall transient / permanent complication rate of approximately 38% in a large series of 126 surgically - treated paraclinoid aneurysms treated over 20 years , with most complications relating to visual function5 ) .
surgery - related complications from this study were much higher in the unruptured paraclinoid aneurysm group ( 62.5% ) than in the ruptured group ( 25.4% ) .
the study also reported an operative mortality rate of 11.6% in all patients presenting with bleeding aneurysms5 ) .
intraoperative monitoring has been only used in unruptured cases to avoid ischemic complications during temporary occlusion of the cervical or supraclinoid ica in the dissection and direct clip application stages of operation . however , in ruptured cases , iom was not used given the emergent conditions .
bypass was always prepared should there be need for it during microsurgical clipping , though it was not used in our study .
untreated aneurysms have a tendency to grow continuously and compress the optic apparatus . there are no methods of treatment leading to visual recovery or improvement30 ) . compared with endovascular techniques , direct obliteration of the aneurysm sac
provides for mass effect reduction , offering the possibility for visual recovery . however , there are instances in which the cause of visual deterioration can not be precisely identified .
optic nerve injury is one of the most common complications after surgical treatment of paraclinoid aneurysms .
possible times at which optic nerve injury can occur are during the removal of the acp and optic strut , with unroofing of the optic canal due to heat or direct injury caused by the high speed drill , and with excessive manipulation or damage to the optic nerve .
extradural drilling of the optic canal in skull base surgery carries a potential risk of damaging the optic nerve and carotid artery4,9,24,32 ) .
simple rongeuring of the acp , optic canal roof , and optic strut with various shaped microrongeurs eliminates the risk of direct mechanical and thermal injury from the use of a high - speed drill instrument in a narrow surgical corridor4,32 ) .
because the optic nerve is particularly sensitive to indirect or direct injury , minimal manipulation is most important in preserving visual function23,32 ) .
the ipsilateral total blindness seen in the patient with the large intracavernous aneurysm ( case 6 ) may be due to a number of causes of optic nerve injury , including long segment decompression of the nerve by unpredicted mechanical injury with vibration or by thermal injury , despite copious irrigation during drilling of the optic canal roof .
intraoperative monitoring of the vep was not helpful in predicting this permanent optic nerve injury .
an accurate preoperative assessment of the origin of these aneurysms is a critical initial step in management .
having accurate microsurgical knowledge about the dural relationships of the paraclinoid region is essential to successful surgical clipping of paraclinoid aneurysms .
it is also important to gain maximal exposure of the aneurysm proximal neck , establish proximal control , and completely obliterate the aneurysms with minimal manipulation of the optic nerve .
. additionally , those operations must be very comfortable and facile with optic strut removal , which is critical for aneurysm proximal neck exposure in most paraclinoid cases .
second , exposure of the cervical ica is an important and useful method for proximal ica control .
third , to avoid optic nerve injury , the pia vessels of the optic nerve must not be disrupted when incising the dura , and retraction of the optic nerve should be brief and minimal .
furthermore , the ophthalmic and superior hypophyseal arteries must be identified before incision of the distal dural ring to avoid inadvertent injury .
the data in our study differed somewhat from what has been shown previously in the literature1,2,5,7,11,15 - 17,26,30 ) in terms of sex ( all females in our study ) , a large number of large and giant aneurysms ( 10/31 , 32.3% ) , and a predominance of carotid cave aneurysms ( 50% ) .
however , certain features including age ( typically diverse in adults , mean age of 50.1 years in our study ) , a presenting symptom of bleeding ( 50% ) , and the incidence of multiple aneurysms ( 3/10 , 30% ) in our study were in line with what has been published previously1,2,5,7,9,10,15 - 17,22,26,30 ) .
the complete removal of the acp , optic canal and strut is an essential step in maximizing proximal neck exposure of large paraclinoid aneurysms and in gaining proximal control of the intracranial ica .
one drawback of the extradural anterior clinoidectomy technique is the limited extent of elevation of the frontotemporal dura over the acp10 ) .
bleeding from the diploic veins or the venous plexus surrounding the clinoid segment of the ica can also make the last step of anterior clinoidectomy difficult .
several authors have recently described incision of the otpf at the level of the lateral edge of the sof as a key step in increasing exposure of the acp , thus facilitating extradural clinoidectomy6,10,27,37 ) .
bone removal techniques using high - speed drills often result in direct mechanical or thermal injury4,36 ) .
since having experienced a case of ipsilateral blindness in intracavernous large aneurysm clipping , we have mainly used microrongeurs or micro kerrison punches when removing the optic canal and optic strut to avoid these surgery - related complications .
chang4 ) reported 45 consecutive anterior clinodectomy cases with a " no - drill " technique with no procedure - related complications in a cranial - based approach to paraclinoid and parasellar lesions .
the greatest hazards relating to the surgical procedure in direct surgical clipping of large / giant paraclinoid aneurysms are microanatomical complexity and restrictions arising from limited space of intracranial proximal control , difficult bone work , broad aneurysm necks , and a lack of comprehensive anatomical knowledge , specifically of 3d contours between the aneurysm and the clinoid ica .
proximal control is another important issue to consider and may be achieved in the cervical carotid artery or the clinoid ica .
we always exposed the common , internal , and external carotid arteries in the neck before performing the craniotomy , and have not favored temporary balloon occlusion or suction maneuvers .
we propose that exposure of the carotid artery in the neck is a much safer procedure as a means of gaining early proximal control . during surgery
, exposure of the clinoid ica and its use as a site of temporary clipping or of proximal control of an unexpected intraoperative rupture of aneurysm can not always be readily achieved .
special recommended clipping techniques to preserve perforators , minimize optic nerve injury , and to achieve complete obliteration of the broad neck of large / giant paraclinoid aneurysms are as follows .
first , short right - angled fenestrated clips which have an aperture larger than the diameter of ica should be used firstly .
second , the short blade , large - aperture fenestrated clips should be applied in a parallel tandem fashion to reconstruct the lumen of the ica without damaging the branching vessels .
third , the use of multiple fenestrated clips with short blades is better than the use of a single long blade clip for reliably and completely occluding broad neck large paraclinoid aneurysms .
five patients had transient or permanent postoperative neurological deficits ( 20% ruptured vs. 75% unruptured aneurysms ) .
the common deficits were visual impairment ( 20% ) and transient motor weakness ( 20% ) .
there were no cases of operative mortality in patients harboring large / giant paraclinoid aneurysms in our series .
a recent study has published an overall transient / permanent complication rate of approximately 38% in a large series of 126 surgically - treated paraclinoid aneurysms treated over 20 years , with most complications relating to visual function5 ) .
surgery - related complications from this study were much higher in the unruptured paraclinoid aneurysm group ( 62.5% ) than in the ruptured group ( 25.4% ) .
the study also reported an operative mortality rate of 11.6% in all patients presenting with bleeding aneurysms5 ) .
intraoperative monitoring has been only used in unruptured cases to avoid ischemic complications during temporary occlusion of the cervical or supraclinoid ica in the dissection and direct clip application stages of operation . however , in ruptured cases , iom was not used given the emergent conditions .
bypass was always prepared should there be need for it during microsurgical clipping , though it was not used in our study .
compared with endovascular techniques , direct obliteration of the aneurysm sac provides for mass effect reduction , offering the possibility for visual recovery . however , there are instances in which the cause of visual deterioration can not be precisely identified .
optic nerve injury is one of the most common complications after surgical treatment of paraclinoid aneurysms .
possible times at which optic nerve injury can occur are during the removal of the acp and optic strut , with unroofing of the optic canal due to heat or direct injury caused by the high speed drill , and with excessive manipulation or damage to the optic nerve .
extradural drilling of the optic canal in skull base surgery carries a potential risk of damaging the optic nerve and carotid artery4,9,24,32 ) .
simple rongeuring of the acp , optic canal roof , and optic strut with various shaped microrongeurs eliminates the risk of direct mechanical and thermal injury from the use of a high - speed drill instrument in a narrow surgical corridor4,32 ) .
because the optic nerve is particularly sensitive to indirect or direct injury , minimal manipulation is most important in preserving visual function23,32 ) .
the ipsilateral total blindness seen in the patient with the large intracavernous aneurysm ( case 6 ) may be due to a number of causes of optic nerve injury , including long segment decompression of the nerve by unpredicted mechanical injury with vibration or by thermal injury , despite copious irrigation during drilling of the optic canal roof .
intraoperative monitoring of the vep was not helpful in predicting this permanent optic nerve injury .
ica reconstruction using the multiple tandem clipping technique with various shaped fenestrated clips is highly valuable in most cases .
therefore , microsurgical direct clipping , under direct visualization of the aneurysm and surrounding neurovascular structures should be considered first - line treatment of large paraclinoid aneurysms .
this is evidenced by the excellent long - term feasibility in complete aneurysm occlusion of the procedure , though the technique may need further study of associated morbidity .
if direct microsurgical clipping is infeasible , endovascular treatment or trapping with or without a bypass procedure , depending on the collateral flow , should be considered . | objectivealthough surgical techniques for clipping paraclinoid aneurysms have evolved significantly in recent times , direct microsurgical clipping of large and giant paraclinoid aneurysms remains a formidable surgical challenge .
we review here our surgical experiences in direct surgical clipping of large and giant paraclinoid aneurysms , especially in dealing with anterior clinoidectomy , distal dural ring resection , optic canal unroofing , clipping techniques , and surgical complications.methodsbetween september 2001 and february 2012 , we directly obliterated ten large and giant paraclinoid aneurysms . in all cases , tailored orbito - zygomatic craniotomies with extradural and/or intradural clinoidectomy were performed .
the efficacy of surgical clipping was evaluated with postoperative digital subtraction angiography and computed tomographic angiography.resultsof the ten cases reported , five each were of ruptured and unruptured aneurysms .
five aneurysms occurred in the carotid cave , two in the superior hypophyseal artery , two in the intracavernous , and one in the posterior wall .
the mean diameter of the aneurysms sac was 18.8 mm in the greatest dimension .
all large and giant paraclinoid aneurysms were obliterated with direct neck clipping without bypass . with the exception of the one intracavenous aneurysm
, all large and giant paraclinoid aneurysms were occluded completely.conclusionthe key features of successful surgical clipping of large and giant paraclinoid aneurysms include enhancing exposure of proximal neck of aneurysms , establishing proximal control , and completely obliterating aneurysms with minimal manipulation of the optic nerve .
our results suggest that internal carotid artery reconstruction using multiple fenestrated clips without bypass may potentially achieve complete occlusion of large paraclinoid aneurysms . |
a total of 350 adolescent girls , born in the years 19871992 and living in the capital area in iceland , were randomly selected from statistics iceland .
six per cent of the original sample did not fulfil these criteria , and 13% could not be reached by phone , leaving 284 subjects . of these , 145 girls ( 51% of the eligible sample ) agreed to participate in the study .
the main reasons for refusing to participate were lack of time or lack of interest .
a total of 112 girls completed the study , but 16 blood samples were insufficient for selenium measurements , leaving 96 girls or 34% of the eligible sample .
the study was approved by the national bioethics committee ( vsnb2007040006 ) and the icelandic data protection commission ( 2007040320 ) and took place between june 2007 and may 2008 .
the subjects weight and height were measured using a digital scale and a stadiometer ( seca , model 708 , hamburg , germany ) to the nearest 100 g and 1 mm , and body mass index ( bmi , kg / m ) was calculated .
the subjects answered a questionnaire on smoking habits and on oral contraceptive use . see table 1 for overview of subjects characteristics .
characteristics of subjects ( n=96 ) bmi : body mass index ( kg / m ) .
samples were stored frozen ( 28c ) in plastic vials and thawed immediately before decomposition .
samples were decomposed by microwave heating under pressure in 45 ml teflon cylinders ( parr , moline , il ) in a microwave oven programmable in three heating steps ( electrolux heatwave autocook ems 2371 ) .
an aliquot of approximately 0.5 ml whole blood was weighed into a cylinder , adding 1.0 ml 30% hydrogen peroxide and 1.5 ml 65% ( w / w ) nitric acid .
six cylinders were placed in the oven at a time , heating for 2 min at 450 w , 1 min at 150 w , and 7 min at 300 w. a clear colorless solution was thus produced , transferred quantitatively to a polystyrene tube ( sarstedt , nmbrecht , germany ) , and diluted with deionized water to 5 ml .
selenium was determined by graphite furnace atomic absorption spectrometry using a perkin elmer analyst 650 spectrometer equipped with a zeeman background corrector .
selenium was quantified using a one - point standard addition technique , adding to each sample , alternatively a blank or a standard containing 30 g / l of selenium .
both addition solutions contained 250 mg / l of platinum ( as nitrate ) and 0.25% ( w / v ) of citric acid for matrix modification .
all determinations were carried out in duplicates , twice without and twice with added selenium , injecting each time 5 l of sample plus 5 l of the addition solution .
a linear regression of signals from all the blanks was used to estimate the zero level for all other measurements .
accuracy was tested using certified reference samples , seronorm blood level-1 and seronorm blood level-2 ( sero as , billingstad , norway ) with a stated selenium content of 80
eight determinations of each reference sample , spread throughout the measurements , yielded average values of 9619% and 10111% , respectively of the reference value .
recommendations for selenium intake , including the nordic nutrient recommendations ( nnr ) , are generally based on the criterion of maximizing plasma glutathione - peroxidase activity ( gpx3 ) ( 14 , 15 ) .
studies have shown that gpx3 is saturated at plasma levels of 7080 g / l ( 1618 ) , which corresponds to 85100
still , blood or serum levels alone are widely used in the literature , and whole blood selenium is considered to reflect long - term intake better than plasma or serum selenium ( 1921 ) .
the current nnr for selenium are 40 g / day for women , with 30 g / day as the average requirement , 20 g / day as the lower limit and 300 g / day as the upper limit of intake ( 15 ) .
dietary intake was assessed using a validated semi - quantitative food frequency questionnaire ( ffq ) ( 22 , 23 ) .
it includes 130 food items from 17 food groups and is designed to reflect food intake over the previous 3 months .
portion sizes were estimated from pictures of three portion sizes of common food items and from general household measures .
the national food composition database ( isgem ) ( 24 ) and icefood nutrient and food calculating program from the icelandic nutrition council were used to calculate the intake of foods in g / day , selenium in g / day , and contribution of each food group to total selenium intake .
isgem was updated in 2009 with respect to energy nutrients , minerals and trace elements , including selenium .
the foods examined most extensively were milk , dairy products , cheese , meat ( 10 ) , fish , cereals , and eggs .
all food samples were collected in 2007 and 2008 , with milk and dairy products sampled in the summer and winter 2008 .
the quality of the new data was evaluated , and the data obtained the highest confidence code established in the eurofir project ( 25 ) .
values for selenium in foods were also obtained from earlier icelandic investigations and foreign sources ( 24 ) .
descriptive and statistical analysis was conducted using the statistical software package spss 11.0 ( spss , inc . ,
variables for selenium in whole blood , total selenium intake , and selenium from bread / cereals and meat / poultry , and the percentage intake from milk / dairy products , fish / seafood and meat / poultry were normally distributed , whereas other variables were skewed .
data are presented as mean and standard deviation ( sd ) and percentiles , as appropriate ( table 2 ) .
total selenium intake and selenium intake from the food groups contributing most to dietary selenium were categorized into highest and lowest quartiles ( q4 ) and ( q1 ) ( table 3 ) .
the association between blood selenium , total selenium intake and selenium intake from different food groups was assessed using spearman 's rho correlation .
the differences in median blood selenium between q4 and q1 for total selenium intake , and selenium from different food groups were tested using the mann
both tests were two - sided , and the level of significance was taken as p 0.05 .
food consumption from different food groups and contribution to selenium intake , and energy and selenium intake as well as blood selenium the sum of mean selenium intake from other food groups including vegetables , fruits , sugar , drinks , and mixed dishes was 20% of the total selenium intake .
correlation ( spearman 's rho ) between whole blood selenium status ( g / l ) and selenium intake from each food group ( g / day ) , total selenium intake ( g / day ) and total selenium intake excluding dietary selenium rom fish ( g / day ) ( n=96 ) median selenium status ( g / l ) in q1 per intake group .
difference in median selenium status ( g / l ) between q4 and q1 in selenium intake from each food group , total selenium and total selenium intake excluding rom fish p value for the difference in median selenium status between q4 and q1 ( mann whitney u test ) .
p value for the difference in median selenium status between q4 and q1 in selenium intake from mann whitney u test .
a total of 350 adolescent girls , born in the years 19871992 and living in the capital area in iceland , were randomly selected from statistics iceland .
six per cent of the original sample did not fulfil these criteria , and 13% could not be reached by phone , leaving 284 subjects . of these , 145 girls ( 51% of the eligible sample ) agreed to participate in the study .
the main reasons for refusing to participate were lack of time or lack of interest .
a total of 112 girls completed the study , but 16 blood samples were insufficient for selenium measurements , leaving 96 girls or 34% of the eligible sample .
the study was approved by the national bioethics committee ( vsnb2007040006 ) and the icelandic data protection commission ( 2007040320 ) and took place between june 2007 and may 2008 .
the subjects weight and height were measured using a digital scale and a stadiometer ( seca , model 708 , hamburg , germany ) to the nearest 100 g and 1 mm , and body mass index ( bmi , kg / m ) was calculated .
the subjects answered a questionnaire on smoking habits and on oral contraceptive use . see table 1 for overview of subjects characteristics .
characteristics of subjects ( n=96 ) bmi : body mass index ( kg / m ) .
samples were stored frozen ( 28c ) in plastic vials and thawed immediately before decomposition .
samples were decomposed by microwave heating under pressure in 45 ml teflon cylinders ( parr , moline , il ) in a microwave oven programmable in three heating steps ( electrolux heatwave autocook ems 2371 ) .
an aliquot of approximately 0.5 ml whole blood was weighed into a cylinder , adding 1.0 ml 30% hydrogen peroxide and 1.5 ml 65% ( w / w ) nitric acid .
six cylinders were placed in the oven at a time , heating for 2 min at 450 w , 1 min at 150 w , and 7 min at 300 w. a clear colorless solution was thus produced , transferred quantitatively to a polystyrene tube ( sarstedt , nmbrecht , germany ) , and diluted with deionized water to 5 ml .
selenium was determined by graphite furnace atomic absorption spectrometry using a perkin elmer analyst 650 spectrometer equipped with a zeeman background corrector .
selenium was quantified using a one - point standard addition technique , adding to each sample , alternatively a blank or a standard containing 30 g / l of selenium .
both addition solutions contained 250 mg / l of platinum ( as nitrate ) and 0.25% ( w / v ) of citric acid for matrix modification .
all determinations were carried out in duplicates , twice without and twice with added selenium , injecting each time 5 l of sample plus 5 l of the addition solution .
a linear regression of signals from all the blanks was used to estimate the zero level for all other measurements .
accuracy was tested using certified reference samples , seronorm blood level-1 and seronorm blood level-2 ( sero as , billingstad , norway ) with a stated selenium content of 80
eight determinations of each reference sample , spread throughout the measurements , yielded average values of 9619% and 10111% , respectively of the reference value .
recommendations for selenium intake , including the nordic nutrient recommendations ( nnr ) , are generally based on the criterion of maximizing plasma glutathione - peroxidase activity ( gpx3 ) ( 14 , 15 ) .
studies have shown that gpx3 is saturated at plasma levels of 7080 g / l ( 1618 ) , which corresponds to 85100
still , blood or serum levels alone are widely used in the literature , and whole blood selenium is considered to reflect long - term intake better than plasma or serum selenium ( 1921 ) .
the current nnr for selenium are 40 g / day for women , with 30 g / day as the average requirement , 20 g / day as the lower limit and 300 g / day as the upper limit of intake ( 15 ) .
dietary intake was assessed using a validated semi - quantitative food frequency questionnaire ( ffq ) ( 22 , 23 ) .
it includes 130 food items from 17 food groups and is designed to reflect food intake over the previous 3 months .
portion sizes were estimated from pictures of three portion sizes of common food items and from general household measures .
the national food composition database ( isgem ) ( 24 ) and icefood nutrient and food calculating program from the icelandic nutrition council were used to calculate the intake of foods in g / day , selenium in g / day , and contribution of each food group to total selenium intake .
isgem was updated in 2009 with respect to energy nutrients , minerals and trace elements , including selenium .
the foods examined most extensively were milk , dairy products , cheese , meat ( 10 ) , fish , cereals , and eggs .
all food samples were collected in 2007 and 2008 , with milk and dairy products sampled in the summer and winter 2008 .
the quality of the new data was evaluated , and the data obtained the highest confidence code established in the eurofir project ( 25 ) .
values for selenium in foods were also obtained from earlier icelandic investigations and foreign sources ( 24 ) .
descriptive and statistical analysis was conducted using the statistical software package spss 11.0 ( spss , inc . ,
variables for selenium in whole blood , total selenium intake , and selenium from bread / cereals and meat / poultry , and the percentage intake from milk / dairy products , fish / seafood and meat / poultry were normally distributed , whereas other variables were skewed .
data are presented as mean and standard deviation ( sd ) and percentiles , as appropriate ( table 2 ) .
total selenium intake and selenium intake from the food groups contributing most to dietary selenium were categorized into highest and lowest quartiles ( q4 ) and ( q1 ) ( table 3 ) .
the association between blood selenium , total selenium intake and selenium intake from different food groups was assessed using spearman 's rho correlation .
the differences in median blood selenium between q4 and q1 for total selenium intake , and selenium from different food groups were tested using the mann
both tests were two - sided , and the level of significance was taken as p 0.05 .
food consumption from different food groups and contribution to selenium intake , and energy and selenium intake as well as blood selenium the sum of mean selenium intake from other food groups including vegetables , fruits , sugar , drinks , and mixed dishes was 20% of the total selenium intake .
correlation ( spearman 's rho ) between whole blood selenium status ( g / l ) and selenium intake from each food group ( g / day ) , total selenium intake ( g / day ) and total selenium intake excluding dietary selenium rom fish ( g / day ) ( n=96 ) median selenium status ( g / l ) in q1 per intake group .
difference in median selenium status ( g / l ) between q4 and q1 in selenium intake from each food group , total selenium and total selenium intake excluding rom fish p value for the difference in median selenium status between q4 and q1 ( mann whitney u test ) .
p value for the difference in median selenium status between q4 and q1 in selenium intake from mann
the main sources of dietary selenium were milk and dairy products , fish , bread , and cereals , as shown in table 2 .
the combined contribution of milk , dairy , and cheese was 3614% of total selenium intake while fish and cereals contributed less .
eighteen girls took vitamin and mineral supplements at least once a week while 10 reported daily usage ( data not shown ) . total selenium intake and blood selenium
median intake was 43 g / day ( range 20135 ) , and about 85% of the subjects were above the average requirement of 30 g / day .
table 3 shows correlations between blood selenium and selenium intake from each food group ( spearman 's rho ) .
there was a modest , but significant , correlation between selenium levels and total selenium intake as well as selenium from cereal products and from fish .
no association was found between dairy consumption ( g / day ) and blood selenium ( r=0.005 ; p=0.002 ) or between selenium from milk / dairy and selenium levels in blood ( r= 0.003 ; p=0.98 ) . excluding selenium from milk , dairy products and cheese resulted in a slightly stronger and more significant correlation between selenium intake and blood concentrations ( r=0.30 ; p=0.003 ) ( data not shown ) .
the median selenium values in whole blood ( g / l ) for q1 and the differences between the median values in q4 and q1 selenium intake groups are shown in table 3 .
there were significant differences in median selenium concentration between q4 and q1 for total selenium intake and dietary selenium from fish / seafood , p=0.04 and p=0.01 , respectively .
the difference was not significant ( p=0.55 ) when dietary selenium from fish / seafood was excluded from total selenium intake ( mann whitney u test ) .
blood selenium was not associated with bmi or energy intake ( spearman 's rho ) , smoking habit or use of contraceptive pills ( mann whitney u test ) .
in this population of icelandic adolescent girls , mean selenium intake was above nnrs , and approximately 85% of the subjects had an intake above the average requirement ( 15 ) . in none of the subjects
g / l , which is the lower level associated with gpx3 saturation ( 1 , 16 ) and nearly 90% were above 100 g / l , the upper level reported for the enzyme saturation ( 17 , 18 ) .
milk / dairy products and cheese contributed approximately one third of dietary selenium , a higher proportion than reported from other european countries as far as we have discovered ( 2 , 26 ) .
while milk consumption has decreased substantially in iceland over the last decades , it still averaged 550 g / day in these adolescent girls .
the selenium content of icelandic milk is also relatively high compared to neighboring countries ( 27 , 28 ) ( 2.4 g/100 g ) ( 24 ) , which is noteworthy as iceland is considered a low selenium area ( 7 ) .
low concentrations of selenium are generally found in hay in iceland , and selenium deficiency has been reported in icelandic livestock ( 9 ) .
high selenium content of supplemental feed for dairy cows is a plausible explanation for the high content found in milk , but the selenium content was 18% lower in summer than in winter milk ( 10 ) .
interestingly , no association was found between the intake of milk and dairy products and selenium in whole blood in spite of their substantial contribution to selenium intake .
it is well known that the absorption and metabolism of selenium from foods varies , depending on the chemical forms as well as on selenium status ( 8 , 29 ) .
consequently , no simple relationship exists between total selenium intake and selenium concentration in blood .
particularly when the level in plasma exceeds 70 g / l , the concentration depends greatly on the form consumed ( 14 , 17 , 30 ) .
the chemical speciation of selenium in cow 's milk is largely determined by the forms present in the feeds ( 31 ) and selenite , the form used in feed for dairy cows in iceland , has been reported not to affect selenium status in selenium - replete individuals ( 12 , 32 , 33 ) .
however , the chemical speciation of selenium in icelandic cow 's milk has not yet been analysed .
the lack of correlation between blood selenium and milk and dairy products is in sharp contrast to our study of iodine status of these same adolescent girls ( 13 ) . in the iodine status study dairy
was not only the food group contributing most to iodine intake , but also the only one that correlated significantly with iodine status .
in contrast , selenium from bread and cereals and from fish , which contributed much less to total selenium intake , did correlate significantly with blood levels .
this is in partial agreement with other studies , including a recent danish study , showing that seafood intake was associated with serum selenium values , while milk consumption showed no such association ( 34 ) . in that study dairy selenium
contributed significantly less to total selenium intake than in our study while fish accounted for a comparable proportion of intake .
the significant difference in selenium concentrations between the highest and lowest quartiles of fish intake further supports the contribution of selenium from fish , while no difference was seen between quartiles for other food groups .
comparable associations with selenium status and fish and seafood have been seen in several studies ( 29 , 3538 ) but not in others ( 39 , 40 ) , possibly resulting from differences in selenium forms and content in different fish species .
selenium is abundant in fish , especially ocean fish ( 41 ) , and according to the isgem database the selenium content in haddock ( melanogrammus aeglefinus ) , the species accounting for 80% of total fish intake in this study ( 13 ) , is 38.8 g/100 g ( wet weight ) ( 24 ) . in cod ,
a close relative of haddock , 70% of the selenium is selenomethionine ( 11 , 42 ) , a form that is readily absorbed and taken indiscriminately into body tissues .
selenomethionine is also the form abundant in wheat ( 11 ) , and , interestingly , selenium from grain was associated with selenium in blood .
wheat selenomethionine has been shown to increase plasma levels even in selenium - replete individuals ( 12 , 43 ) while no similar increases in plasma are observed with other biochemical forms of selenium .
considering the adequate selenium status of our subjects , the observed association with fish and cereal intake but not with milk and dairy products , may result from the form of selenium in these foods .
practically no grain is grown in the country for human consumption , and cereals have traditionally been sparse in the icelandic diet .
nowadays most of the wheat imported to iceland comes from low - selenium areas in europe with a mean concentration of 3.3 g/100 g. american wheat , which was until recently the most commonly imported wheat to the country , contains approximately 10 times more selenium ( 24 , 28 ) . as a result , when older selenium values from the icelandic nutrient database were used to calculate these same intake data , cereals accounted for 2510% of total selenium intake ( results not shown ) rather than the 137% reported presently .
the only previous study on blood selenium in iceland published in 1983 showed mean whole blood selenium of 12720 g / l in healthy adults ( n=43 ) ( 44 ) , compared with 11716 g / l in our study .
direct comparisons are difficult because of the age and sex difference , as well as different methodology . in the earlier study ,
however values would be expected to be lower now than earlier considering decreased fish intake in iceland and decreased selenium in wheat . according to national nutrition surveys ,
mean adult fish intake decreased from 73 g / day in 1990 to 40 g / day in 2002 , and that year the amount consumed by young girls was the lowest of any age group , or 15 g / day ( 4 ) , which is comparable to the 14 g / day observed in this study .
an accepted optimal reference has not been established for blood or plasma selenium and appropriate biomarkers for selenium status are still under debate . in our study , the mean blood level of 117 g / l is within the range associated with maximal gpx3 saturation , and no girl had levels associated with selenium insufficiency . however , only about 30% of the girls reached the blood selenium concentrations of 120 g / l associated with maximal expression of selenoprotein p ( 2 , 45 ) , and 5% were above 150 g / l , the level that has been associated with decreased mortality and potential cancer protection ( 1 , 46 ) .
no association was found between selenium in whole blood and bmi , energy intake , smoking habits , or use of contraceptive pills .
however , smoking has been reported to increase oxidative stress and may thus increase selenium requirements ( 47 ) .
the number of daily smokers in our study may not have been sufficient to demonstrate any putative relationship between smoking and selenium levels .
a limitation to our study is the low participation rate , i.e. 34% of the eligible sample .
the girls participating in the study possibly had better diets and selenium status than girls of this age in general , thereby biasing the results .
however , this group of girls was found to be representative of icelandic adolescent girls with respect to overweight and obesity prevalence ( 4 ) .
also , their food intake , including intake of fish and milk , resembled the average intakes in iceland in this age group , according to the most recent national nutrition survey ( 4 ) .
we therefore conclude that their food intake may adequately reflect that of the original sample .
the use of a ffq to assess food and selenium intake may be considered a limitation . however , a validation study has demonstrated acceptable assessment of all the major food groups and nutrients ( 22 , 23 ) .
the foods most likely to be underestimated are sweets and soda foods that do not contribute significantly to selenium intake .
furthermore , ffqs including more than 100 food items have been shown to adequately assess selenium intake ( 48 ) .
also , a combination of two or more biomarkers may better reflect both nutritional status and intake from selected foods ( 2 , 47 ) . however , selenium concentrations in blood are widely used and available for comparisons between populations and time periods .
also blood levels may be a simple way to detect possible insufficiency in a population for public health purposes .
an important strength of the study includes the careful analysis of selenium in foods for the national database , with food sampling and analysis carried out during the same time period as the blood was collected from the subjects . as the selenium content of foods , including milk , meat , and cereals ,
varies greatly according to feeding practices of cattle as well as soil conditions , the levels registered in food tables may lead to invalid conclusions regarding intake when measurements are not quite up to date .
in this population of icelandic adolescent girls , selenium intake and blood levels appear acceptable even though they do not reach the levels associated with possible cancer risk protection .
milk and dairy products contribute most to selenium intake , while fish and cereals appear to be the most important contributors to blood selenium , judging from associations between intake and blood levels in this population of mostly selenium - replete subjects .
the study was supported by the landspitali university hospital research fund and the agricultural productivity fund . | background / objectivessignificant changes have been reported in dietary habits and food availability in iceland that would be expected to compromise selenium intake and status , especially among young people .
these include substantial decreases in the consumption of fish and milk , as well as the selenium content of imported wheat .
the aim of this study was to assess selenium in the diet and whole blood of adolescent girls , as well as define the most important foods contributing to intake and blood concentrations of selenium.designthe subjects were 96 randomly selected girls , aged 1620 , who answered a validated food frequency questionnaire ( ffq ) for dietary assessment .
selenium intake from each food group was calculated in g / day .
blood samples were collected for measurement of whole blood selenium.resultsmean dietary selenium was 5125 g / day .
milk / dairy products , including cheese , contributed 3614% of total dietary selenium ; fish 1812% ; and bread / cereal products 136% .
mean whole blood selenium was 11712 g / l ( range 90208 ) ; nearly 90% of subjects were above the optimal level of 100 g / l .
fish and bread / cereal products were the only foods significantly correlated with selenium in blood ( r=0.32 ; p=0.002 and r=0.22 ; p=0.04 , respectively ) while no correlation was found with milk and dairy products in spite of their greater contribution to total selenium intake.conclusionin this population of icelandic adolescent girls , selenium intake and status seem acceptable . judging from associations between intake and blood levels , fish and cereals may be the most important contributors to blood selenium . |