bluuebunny/crossref_metadata_2025 huggingface dataset:
When Labels Hurt but Novelty Helps: Children's Perseveration and Flexibility in a Card‐Sorting Task
Authors: Yerys Benjamin E. , Munakata Yuko
Published: November 2006

Children often perseverate, repeating prior behaviors when inappropriate. This work tested the roles of verbal labels and stimulus novelty in such perseveration. Three‐year‐old children sorted cards by one rule and were then instructed to switch to a second rule. In a basic condition, cards had familiar shapes and colors and both rules were stated explicitly. In an uninformative‐label condition, cards had familiar shapes and colors, but the first rule was not stated explicitly. In a novel‐stimuli condition, both rules were stated explicitly but stimuli were novel on the first sorting dimension. More children switched to the second rule in the uninformative‐label and novel‐stimuli conditions than in the basic condition. Implications for theories of cognitive flexibility are discussed.
The Limits of Genetic Influence: A Behavior‐Genetic Analysis of Infant–Caregiver Relationship Quality and Temperament
Authors: Roisman Glenn I. , Fraley R. Chris
Published: November 2006

This report presents data on 9‐month‐old twin pairs (nMZ=172; nDZ=333) from the Early Childhood Longitudinal Study, demonstrating that the role of genetic variation among infants is trivial and the shared and nonshared environment is substantial in accounting for the observed quality of infant–caregiver relationships. In contrast, maternal reports of temperament were best accounted for by genetic variation and nonshared environmental influences. Interestingly, however, shared environmental effects were documented for observations of temperament. Consistent with a growing database, the current study calls into question the ubiquity of heritability effects in all domains of psychological inquiry. It also bolsters consensus in the field of developmental psychology that shared environmental effects are not as elusive as had once been thought.
Do Individuals With Autism Process Categories Differently? The Effect of Typicality and Development
Authors: Gastgeb Holly Zajac , Strauss Mark S. , Minshew Nancy J.
Published: November 2006

This study examined the effect of exemplar typicality on reaction time and accuracy of categorization. High‐functioning children (age 9–12), adolescents (age 13–16), and adults with autism (age 17–48) and matched controls were tested in a category verification procedure. All groups showed improved processing throughout the lifespan for typical and somewhat typical category exemplars. However, individuals with autism responded more slowly than matched controls to atypical exemplars at all ages. The results are discussed in terms of potential differences in the type of processing that may be required for categorizing typical and atypical category exemplars. Parallels are also drawn to the results of previous studies on face processing in individuals with autism.
Processing Limitations in Children With Specific Language Impairment: The Role of Executive Function
Authors: Im‐Bolter Nancie , Johnson Janice , Pascual‐Leone Juan
Published: November 2006

Research suggests that children with specific language impairment (SLI) have processing limitations; however, the mechanisms involved have not been well defined or investigated in a theory‐guided manner. The theory of constructive operators was used as a framework to explore processes underlying limited processing capacity in children with SLI. Mental attentional capacity, mental attentional interruption, and 2 specific executive functions (shifting and updating) were examined in 45 children with SLI and 45 children with normally developing language, aged 7 to 12 years. The results revealed overall group differences in performance on measures of mental attention, interruption, and updating, but not shifting. The findings supported the premise that mental attention predicted language competence, but that this relationship was mediated partially by updating.
‘You tell all the stories’: Using narrative to explore hierarchy within a Community of Practice1
Authors: Moore Emma
Published: November 2006

Recent discussion of the Community of Practice (CofP) (Davies 2005) has suggested that there are certain limitations to the approach with regard to how it accounts for internal hierarchy and community membership.Eckert and Wenger(2005: 588) have suggested that the only way to evaluate such criticism (and avoid building an inappropriately rigid conception of power into CofP theory) is to explore how hierarchies operate within CofPs. This paper offers such an exploration. Using data from a long‐term ethnographic study of a high school in the north‐west of England, this paper will use narrative analysis (drawing upon the work ofLabov and Waletsky [1967] 1997amongst others) to explore the interactional space in which speakers actively negotiate their personal and community behaviour. The analysis focuses upon the role individuals play as narrators of community practice and illustrates that status inequalities between individual CofP members do not necessarily result in inequitable allocation of control within the CofP.
Quality of Life of Workers with an Intellectual Disability in Supported Employment
Authors: Verdugo M. A. , Jordán de Urríes F. B. , Jenaro C. , Caballo C. , Crespo M.
Published: November 2006

Aim This study investigate what characteristics of supported employment increase quality of life and whether quality of life is higher in supported employment workers or the sheltered ones in Spain. Typicalness, the degree to which the characteristics of a job are the same as those of co‐workers without a disability in the same company, was considered as one of the supported employment characteristics in the analysis.

Method Two groups were put together to obtain the data using two questionnaires that were administered by trained professionals. Correlational analysis of the data andmanovawere also employed.

Results No differences were found between the two groups regarding quality of life but results indicate that in supported employment, high levels of typicalness are associated with a higher quality of life and that the handling of certain characteristics of support and the job, for example the hours of direct external support, are related to the enhancement of quality of life of the workers.

Conclusions Workers in supported employment show the same quality of life as those in sheltered employment centers. In Spain, the greater the typicalness of the employment, the higher the quality of life. The implications of this for the amount of direct external support for workers with disability is that such support should be used only when absolutely necessary – the minimum support necessary to encourage development.
Mifepristone‐ and misoprostol‐induced mid‐trimester termination of pregnancy: A review of 272 cases
Authors: ROSE Sally B. , SHAND Carol , SIMMONS Ann
Published: November 2006

Background:  Mifepristone became available in New Zealand in 2001, and was first used for second trimester terminations at the Level J Unit, Wellington Hospital. The protocol is based on that published by Ashok et al. in Aberdeen.1

Aims:  To describe the use of mifepristone prior to misoprostol induction of labour for mid‐trimester termination and to compare outcomes with the published data.

Methods:  A retrospective audit of prospectively collected notes for 272 women presenting for mid‐trimester termination of pregnancy in a hospital termination clinic. Data collection included age, ethnicity, previous pregnancies, gestational age, induction‐to‐abortion interval, analgesia, and complications. Data were entered into an Access database and imported into Excel and Epi Info for the computation of descriptive statistics.

Results:  Data on completed abortion were available for 271 women (one chose not to continue the abortion following mifepristone). The median time to abortion was 6 h, and mean number of doses of misoprostol was three. The proportion of women who aborted within 24 h was 95.9%. Immediate surgical evacuation of retained placenta was required in 22 women (8.1%). Heavy bleeding occurred in 22 women (8.1%), and seven required a transfusion (2.6%). The proportion of women who required parenteral narcotics was 78.2%.

Conclusions:  Outcomes for women in the present review were comparable with those for previous publications using the same regimen, with the exception of a higher transfusion rate. Our experience supports the finding that the use of mifepristone as pretreatment to misoprostol results in a shorter induction‐to‐delivery interval than the use of misoprostol alone as has been reported by other groups.
Inadequate compliance with periconceptional folic acid supplementation in South Australia
Authors: CONLIN Melissa L. , MacLENNAN Alastair H. , BROADBENT Jessica L.
Published: November 2006

Background:  Despite recommendations for women to take folic acid supplements, there has been little reduction in the number of neural tube defect cases occurring each year.

Aims:  To assess the level of compliance of pregnant women to recommendations for folic acid supplementation in South Australia, and audit the labelled content in reported supplements used.

Methods:  A survey was conducted from May to September 2005 with 304 pregnant women recruited from antenatal clinics at the Lyell McEwin Health Service, the Women's and Children's Hospital and the Modbury Hospital in Adelaide.

Results:  Full compliance with supplementation recommendations for both timing and dose was achieved by 30% of women. Partial compliance was achieved by 43%, while 27% took no folic acid supplements.

Conclusions:  There is currently poor compliance with folic acid supplementation around conception. Additional food fortification may better achieve an adequate daily level of folic acid.
Periconceptional folic acid use among women giving birth at Queen Mary Maternity Hospital in Dunedin
Authors: DOBSON Isla , DEVENISH Celia , SKEAFF C. Murray , GREEN Tim J.
Published: November 2006

Background:  The New Zealand Ministry of Health advises that all women planning a pregnancy take a folic acid supplement to reduce the risk of having a neural tube defect (NTD)‐affected pregnancy. There is little information available to determine if women are following this advice.

Objective:  The purpose of this study was to determine periconceptional folic acid use among women in the postnatal ward of Queen Mary Maternity Hospital in Dunedin.

Methods:  A questionnaire was administered to women in the postnatal ward between 14 November and 22 December 2004.

Results:  One hundred and six women were interviewed during the study period. Forty women (39%) used folic acid supplements before conception. Sixty‐seven women (64%) planned their pregnancy. The proportion of women (P < 0.001) who planned their pregnancy (53%) and used folic acid before conception was higher than those who did not (11%). The proportion of women  30 years of age (55%) who took folic acid supplements before conception was higher than women aged 17 to < 25 years (10%).

Conclusion:  Despite a lack of a public health campaign in New Zealand, a high proportion of participants, especially those who planned their pregnancy, took folic acid during the periconceptional period. A comprehensive public health campaign is needed to increase folic acid use. Fortification may be required to reach those women who do not plan their pregnancies.
Postgraduate obstetrics and gynaecology experience: The role for early exposure
Authors: ROZEN Warren Matthew , ROZEN Genia
Published: November 2006

Background:  The early postgraduate years provide the opportunity for junior doctors to gain a range of experience and determine their focused areas of interest. Internship thus requires experience in medicine, surgery and the emergency department. Obstetrics and gynaecology (O & G) is not offered as an internship rotation, despite its suitability as such. A cross‐sectional analysis of junior doctors was performed to assess residents’ views on the suitability of an O & G rotation for career decision‐making and for achieving sufficient clinical experience.

Methods:  Fifty‐two resident medical staff in their second postgraduate year were recruited and each was given an anonymous survey for completion. Visual analogue scales (VAS) were used for participant responses.

Results:  For whether internship without an O & G rotation provides sufficient experience to include or exclude O & G as a career choice, the average participant response was 2.1 (on a VAS out of 10) (P < 0.0001). For whether an O & G internship rotation would provide adequate medical, surgical or emergency department experience, the average response was 7.9 (on the VAS out of 10) (P < 0.0001). As to whether participants would have preferred to undergo an O & G rotation during internship, the average response was 7.7 (P < 0.0001).

Conclusion:  The present study demonstrated a perception by residents that an O & G rotation during internship would achieve adequate clinical competencies and assist in career decision‐making in O & G, with residents preferring to have undergone an O & G rotation during internship.
Timing of placental delivery to prevent post‐partum haemorrhage: Lessons learned from an abandoned randomised clinical trial
Authors: MAGANN Everett F. , DOHERTY Dorota A. , BRIERY Christian M. , NIEDERHAUSER Amy , MORRISON John C.
Published: November 2006

It has been recognised that, if the length of the third stage of labour exceeds 30 min, then there is an increased risk of a post‐partum haemorrhage. Recent information has suggested that 18 min is the optimal time for removal of the undelivered placenta to prevent a post‐partum haemorrhage. A randomised trial comparing 20 vs. 30 min was stopped after an interim analysis because only eight of 1607 patients’ placentas had not delivered by 20 min. A third stage of labour that exceeded 10 min was observed to be significantly correlated with an increased risk of post‐partum haemorrhage.
Aberrant interchain disulfide bridge of tissue‐nonspecific alkaline phosphatase with an Arg433→Cys substitution associated with severe hypophosphatasia
Authors: Nasu Makiko , Ito Masahiro , Ishida Yoko , Numa Natsuko , Komaru Keiichi , Nomura Shuichi , Oda Kimimitsu
Published: November 2006

Various mutations in the tissue‐nonspecific alkaline phosphatase (TNSALP) gene are responsible for hypophosphatasia characterized by defective bone and tooth mineralization; however, the underlying molecular mechanisms remain largely to be elucidated. Substitution of an arginine at position 433 with a histidine [TNSALP(R433H)] or a cysteine [TNSALP(R433C)] was reported in patients diagnosed with the mild or severe form of hypophosphatasia, respectively. To define the molecular phenotype of the two TNSALP mutants, we sought to examine them in transient (COS‐1) and conditional (CHO‐K1 Tet‐On) heterologous expression systems. In contrast to an 80 kDa mature form of the wild‐type and TNSALP(R433H), a unique disulfide‐bonded 160 kDa molecular species appeared on the cell surface of the cells expressing TNSALP(R433C). Sucrose density gradient centrifugation demonstrated that TNSALP(R433C) forms a disulfide‐bonded dimer, instead of being noncovalently assembled like the wild‐type. Of the five cysteine residues per subunit of the wild‐type, only Cys102 is thought to be present in a free form. Replacement of Cys102 with serine did not affect the dimerization state of TNSALP(R433C), implying that TNSALP(R433C) forms a disulfide bridge between the cysteine residues at position 433 on each subunit. Although the cross‐linking did not significantly interfere with the intracellular transport and cell surface expression of TNSALP(R433C), it strongly inhibited its alkaline phosphatase activity. This is in contrast to TNSALP(R433H), which shows enzyme activity comparable to that of the wild‐type. Importantly, addition of dithiothreitol to the culture medium was found to partially reduce the amount of the cross‐linked form in the cells expressing TNSALP(R433C), concomitantly with a significant increase in enzyme activity, suggesting that the cross‐link between two subunits distorts the overall structure of the enzyme such that it no longer efficiently carries out its catalytic function. Increased susceptibility to proteases confirmed a gross conformational change of TNSALP(R433C) compared with the wild‐type. Thus, loss of function resulting from the interchain disulfide bridge is the molecular basis for the lethal hypophosphatasia associated with TNSALP(R433C).
A new type of long gamma-ray burst
Authors: King Andrew , Olsson Emma , Davies Melvyn B.
Published: November 2006

We consider gamma-ray bursts (GRBs) produced by the merger of a massive white dwarf with a neutron star. We show that these are likely to produce long-duration GRBs, in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation, and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions, and could have any type of host galaxy. Thus a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that our proposed class may be an important contributor to the observed GRB rate.
Recombinant activated factor VII for trauma patients
Authors: DUTTON RICHARD P.
Published: November 2006

The use of recombinant activated factor VII (rFVIIa) in trauma patients is an exciting application because hemorrhage and coagulopathy play prominent roles both in the syndrome of severe hemorrhagic shock and in severe traumatic brain injury (TBI). Anecdotal use of rFVIIa in non‐hemophilic trauma patients extends back to 1999, and experience at individual institutions is now in the hundreds of cases. Efficacy in controlling traumatic coagulopathy approaches 80%, with long‐term survival of about half of the patients treated. There have been few reports of inappropriate thrombotic events in trauma patients. A single prospective randomized study of rFVIIa in victims of hemorrhagic shock has been completed, with some favorable results. Further trials in hemorrhagic shock are underway in both European and American trauma centers, while a trial in TBI patients will begin within the coming year.
Estimation of Microbial Contamination of Food from Prevalence and Concentration Data: Application to
Listeria monocytogenes
in Fresh Vegetables
Authors: Crépet Amélie , Albert Isabelle , Dervin Catherine , Carlin Frédéric
Published: November 2006

A normal distribution and a mixture model of two normal distributions in a Bayesian approach using prevalence and concentration data were used to establish the distribution of contamination of the food-borne pathogenic bacteria
Listeria monocytogenes
in unprocessed and minimally processed fresh vegetables. A total of 165 prevalence studies, including 15 studies with concentration data, were taken from the scientific literature and from technical reports and used for statistical analysis. The predicted mean of the normal distribution of the logarithms of viable
L. monocytogenes
per gram of fresh vegetables was −2.63 log viable
L. monocytogenes
organisms/g, and its standard deviation was 1.48 log viable
L. monocytogenes
organisms/g. These values were determined by considering one contaminated sample in prevalence studies in which samples are in fact negative. This deliberate overestimation is necessary to complete calculations. With the mixture model, the predicted mean of the distribution of the logarithm of viable
L. monocytogenes
per gram of fresh vegetables was −3.38 log viable
L. monocytogenes
organisms/g and its standard deviation was 1.46 log viable
L. monocytogenes
organisms/g. The probabilities of fresh unprocessed and minimally processed vegetables being contaminated with concentrations higher than 1, 2, and 3 log viable
L. monocytogenes
organisms/g were 1.44, 0.63, and 0.17%, respectively. Introducing a sensitivity rate of 80 or 95% in the mixture model had a small effect on the estimation of the contamination. In contrast, introducing a low sensitivity rate (40%) resulted in marked differences, especially for high percentiles. There was a significantly lower estimation of contamination in the papers and reports of 2000 to 2005 than in those of 1988 to 1999 and a lower estimation of contamination of leafy salads than that of sprouts and other vegetables. The interest of the mixture model for the estimation of microbial contamination is discussed.
Acid Tolerance of
Streptococcus macedonicus
as Assessed by Flow Cytometry and Single-Cell Sorting
Authors: Papadimitriou Konstantinos , Pratsinis Harris , Nebe-von-Caron Gerhard , Kletsas Dimitris , Tsakalidou Effie
Published: November 2006

An in situ flow cytometric viability assay employing carboxyfluorescein diacetate and propidium iodide was used to identify
Streptococcus macedonicus
acid tolerance phenotypes. The logarithmic-phase acid tolerance response (L-ATR) was evident when cells were (i) left to autoacidify unbuffered medium, (ii) transiently exposed to nonlethal acidic pH, or (iii) systematically grown under suboptimal acidic conditions (acid habituation). Stationary-phase ATR was also detected; this phenotype was gradually degenerated while cells resided at this phase. Single-cell analysis of
S. macedonicus
during induction of L-ATR revealed heterogeneity in both the ability and the rate of tolerance acquisition within clonal populations. L-ATR was found to be partially dependent on de novo protein synthesis and compositional changes of the cell envelope. Interestingly, acid-habituated cells were interlaced in lengthier chains and exhibited an irregular pattern of active peptidoglycan biosynthesis sites when probed with BODIPY FL vancomycin. L-ATR caused cells to retain their membrane potential after lethal challenge, as judged by ratiometric analysis with oxonol [DiBAC
4
(3)]. Furthermore, F-ATPase was important during the induction of L-ATR, but in the case of a fully launched response, inhibition of F-ATPase affected acid resistance only partially. Activities of both F-ATPase and the glucose-specific phosphoenolpyruvate-dependent phosphotransferase system were increased after L-ATR induction, distinguishing
S. macedonicus
from oral streptococci. Finally, the in situ viability assessment was compared to medium-based recovery after single-cell sorting, revealing that the culturability of subpopulations with identical fluorescence characteristics is dependent on the treatments imposed to the cells prior to acid challenge.
Cryptococcus neoformans
Can Utilize the Bacterial Melanin Precursor Homogentisic Acid for Fungal Melanogenesis
Authors: Frases Susana , Salazar Angela , Dadachova Ekaterina , Casadevall Arturo
Published: November 2006

Cryptococcus neoformans
melanizes in the environment and in mammalian tissues, but the process of melanization in either venue is mysterious given that this microbe produces melanin only from exogenous substrates. Understanding the process of melanization is important because melanization is believed to protect against various stresses in the environment, including UV radiation, and pigment production is associated with virulence. Melanization in
C. neoformans
requires the availability of diphenolic precursors. In contrast, many bacteria synthesize melanin from homogentisic acid (HGA). We report that
C. neoformans
strains representing all four serotypes can produce a brown pigment from HGA. The brown pigment was acid resistant and had the electron paramagnetic resonance spectrum of a stable free radical, qualities that identified it as a melanin. Melanin “ghost”-like particles obtained from pigmented
C. neoformans
cells were hydrophobic, fluorescent under a variety of irradiation wavelengths, negatively charged, insoluble in organic solvents and alcohols, resistant to degradation by strong acids, and vulnerable to bleaching. HGA melanization was laccase dependent and repressed by high concentrations of glucose. The ability of
C. neoformans
to utilize a bacterial melanin precursor compound suggests a new substrate source for melanization in the environment.
Involvement of
Pseudomonas aeruginosa
Rhodanese in Protection from Cyanide Toxicity
Authors: Cipollone Rita , Frangipani Emanuela , Tiburzi Federica , Imperi Francesco , Ascenzi Paolo , Visca Paolo
Published: November 2006

Cyanide is a serious environmental pollutant and a biocontrol metabolite in plant growth-promoting
Pseudomonas
species. Here we report on the presence of multiple sulfurtransferases in the cyanogenic bacterium
Pseudomonas aeruginosa
PAO1 and investigate in detail RhdA, a thiosulfate:cyanide sulfurtransferase (rhodanese) which converts cyanide to less toxic thiocyanate. RhdA is a cytoplasmic enzyme acting as the principal rhodanese in
P. aeruginosa
. The
rhdA
gene forms a transcriptional unit with the PA4955 and
psd
genes and is controlled by two promoters located upstream of PA4955 and
rhdA
. Both promoters direct constitutive RhdA expression and show similar patterns of activity, involving moderate down-regulation at the stationary phase or in the presence of exogenous cyanide. We previously observed that RhdA overproduction protects
Escherichia coli
against cyanide toxicity, and here we show that physiological RhdA levels contribute to
P. aeruginosa
survival under cyanogenic conditions. The growth of a Δ
rhdA
mutant is impaired under cyanogenic conditions and fully restored upon complementation with
rhdA
. Wild-type
P. aeruginosa
outcompetes the Δ
rhdA
mutant in cyanogenic coculture assays. Hence, RhdA could be regarded as an effector of
P. aeruginosa
intrinsic resistance to cyanide, insofar as it provides the bacterium with a defense mechanism against endogenous cyanide toxicity, in addition to cyanide-resistant respiration.
Production of Antibacterial Compounds and Biofilm Formation by
Roseobacter
Species Are Influenced by Culture Conditions
Authors: Bruhn Jesper Bartholin , Gram Lone , Belas Robert
Published: November 2006

Bacterial communities associated with marine algae are often dominated by members of the
Roseobacter
clade, and in the present study, we describe
Roseobacter
phenotypes that may provide this group of bacteria with selective advantages when colonizing this niche. Nine of 14 members of the
Roseobacter
clade, of which half were isolated from cultures of the dinoflagellate
Pfiesteria piscicida
, produced antibacterial compounds. Many non-
Roseobacter
marine bacteria were inhibited by sterile filtered supernatants of
Silicibacter
sp. TM1040 and
Phaeobacter
(formerly
Roseobacter
) strain 27-4, which had the highest production of antibacterial compound. In contrast,
Roseobacter
strains were susceptible only when exposed to concentrated compound. The production of antibacterial compound was influenced by the growth conditions, as production was most pronounced when bacteria were grown in liquid medium under static conditions. Under these conditions,
Silicibacter
sp. TM1040 cells attached to one another, forming rosettes, as has previously been reported for
Phaeobacter
27-4. A spontaneous
Phaeobacter
27-4 mutant unable to form rosettes was also defective in biofilm formation and the production of antibacterial compound, indicating a possible link between these phenotypes. Rosette formation was observed in 8 of 14
Roseobacter
clade strains examined and was very pronounced under static growth in 5 of these strains. Attachment to surfaces and biofilm formation at the air-liquid interface by these five strains was greatly facilitated by growth conditions that favored rosette formation, and rosette-forming strains were 13 to 30 times more efficient in attaching to glass compared to strains under conditions where rosette formation was not pronounced. We hypothesize that the ability to produce antibacterial compounds that principally inhibit non-
Roseobacter
species, combined with an enhancement in biofilm formation, may give members of the
Roseobacter
clade a selective advantage and help to explain the dominance of members of this clade in association with marine algal microbiota.
Recombinant Bactericidal/Permeability-Increasing Protein rBPI21Protects against Pneumococcal Disease
Authors: Srivastava Amit , Casey Heather , Johnson Nathaniel , Levy Ofer , Malley Richard
Published: November 2006

Bactericidal/permeability-increasing (BPI) protein has been shown to play an important role in innate immunity to gram-negative bacteria, by direct microbicidal as well as endotoxin-neutralizing action. Here we examined potential interactions between a recombinant 21-kDa bioactive fragment of BPI, rBPI21, and the gram-positive pathogenStreptococcus pneumoniae. rBPI21bound to pneumococci and pneumolysin (Ply) in a direct and specific fashion. We observed an enhanced inflammatory response in mouse macrophages when rBPI21was combined with killed pneumococci or supernatant from overnight growth of pneumococci. In addition, rBPI21augmented the proapoptotic activity of Ply+(but not Ply−) pneumococci in TLR4-defective murine macrophages (known to be defective also in their apoptotic response to pneumolysin) in a tumor necrosis factor alpha-dependent manner. rBPI21also enhanced the association of pneumococci with murine macrophages. In a model of invasive pneumococcal disease in TLR4-defective mice, the intranasal administration of rBPI21following intranasal inoculation of Ply+pneumococci both enhanced upper respiratory tract cell apoptosis and prolonged survival. We have thus discovered a novel interaction between pneumococcus and rBPI21, a potent antimicrobial peptide previously considered to target only gram-negative bacteria.
Characterization of the Urease Operon of
Brucella abortus
and Assessment of Its Role in Virulence of the Bacterium
Authors: Sangari Félix J. , Seoane Asunción , Rodríguez María Cruz , Agüero Jesús , García Lobo Juan M.
Published: November 2006

Most members of the genus
Brucella
show strong urease activity. However, the role of this enzyme in the pathogenesis of
Brucella
infections is poorly understood. We isolated several Tn
5
insertion mutants deficient in urease activity from
Brucella abortus
strain 2308. The mutations of most of these mutants mapped to a 5.7-kbp DNA region essential for urease activity. Sequencing of this region, designated
ure1
, revealed the presence of seven open reading frames corresponding to the urease structural proteins (UreA, UreB, and UreC) and the accessory proteins (UreD, UreE, UreF, and UreG). In addition to the urease genes, another gene (
cobT
) was identified, and inactivation of this gene affected urease activity in
Brucella
. Subsequent analysis of the previously described sequences of the genomes of
Brucella
spp. revealed the presence of a second urease cluster,
ure2
, in all them. The
ure2
locus was apparently inactive in
B. abortus
2308. Urease-deficient mutants were used to evaluate the role of urease in
Brucella
pathogenesis. The urease-producing strains were found to be resistant in vitro to strong acid conditions in the presence of urea, while urease-negative mutants were susceptible to acid treatment. Similarly, the urease-negative mutants were killed more efficiently than the urease-producing strains during transit through the stomach. These results suggested that urease protects brucellae during their passage through the stomach when the bacteria are acquired by the oral route, which is the major route of infection in human brucellosis.
The Rab6 Effector Bicaudal D1 Associates with
Chlamydia trachomatis
Inclusions in a Biovar-Specific Manner
Authors: Moorhead A. R. , Rzomp K. A. , Scidmore M. A.
Published: November 2006

Chlamydia
species are obligate intracellular bacteria that replicate within a membrane-bound vacuole, the inclusion, which is trafficked to the peri-Golgi region by processes that are dependent on early chlamydial gene expression. Although neither the host nor the chlamydial proteins that regulate the intracellular trafficking have been clearly defined, several enhanced green fluorescent protein (EGFP)-tagged Rab GTPases, including Rab6, are recruited to
Chlamydia trachomatis
inclusions. To further characterize the association of Rab6 with
C. trachomatis
inclusions, we examined the intracellular localization of guanine nucleotide-binding mutants of Rab6 and demonstrated that only active GTP-bound and not inactive GDP-bound EGFP-Rab6 mutants were recruited to the inclusion, suggesting that EGFP-Rab6 interacts with the inclusion via a host Rab6 effector or a chlamydial protein that mimics a Rab6 effector. Using EGFP-tagged fusion proteins, we also demonstrated that the Rab6 effector Bicaudal D1 (BICD1) localized to
C. trachomatis
inclusions in a biovar-specific manner. In addition, we demonstrated that EGFP-Rab6 and its effector EGFP-BICD1 are recruited to the inclusion in a microtubule- and Golgi apparatus-independent but chlamydial gene expression-dependent mechanism. Finally, in contrast to the Rab6-dependent Golgi apparatus localization of endogenous BICD1, EGFP-BICD1 was recruited to the inclusion by a Rab6-independent mechanism. Collectively, these data demonstrate that neither Rab6 nor BICD1 is trafficked to the inclusion via a Golgi apparatus-localized intermediate, suggesting that each protein is trafficked to the
C. trachomatis
serovar L2 inclusion by a unique, but as-yet-undefined, mechanism.
Streptococcus iniae
Capsule Impairs Phagocytic Clearance and Contributes to Virulence in Fish
Authors: Locke Jeffrey B. , Colvin Kelly M. , Datta Anup K. , Patel Silpa K. , Naidu Nandita N. , Neely Melody N. , Nizet Victor , Buchanan John T.
Published: November 2006

Surface capsular polysaccharides play a critical role in protecting several pathogenic microbes against innate host defenses during infection. Little is known about virulence mechanisms of the fish pathogen
Streptococcus iniae
, though indirect evidence suggests that capsule could represent an important factor. The putative
S. iniae
capsule operon contains a homologue of the
cpsD
gene, which is required for capsule polymerization and export in group B
Streptococcus
and
Streptococcus pneumoniae
. To elucidate the role of capsule in the
S. iniae
infectious process, we deleted
cpsD
from the genomes of two virulent
S. iniae
strains by allelic exchange mutagenesis to generate the isogenic capsule-deficient Δ
cpsD
strains. Compared to wild-type
S. iniae
, the Δ
cpsD
mutants had a predicted reduction in buoyancy and cell surface negative charge. Transmission electron microscopy confirmed a decrease in the abundance of extracellular capsular polysaccharide. Gas-liquid chromatography-mass spectrometry analysis of the
S. iniae
extracellular polysaccharides showed the presence of
l
-fucose,
d
-mannose,
d
-galactose,
d
-glucose,
d
-glucuronic acid,
N
-acetyl-
d
-galactosamine, and
N
-acetyl-
d
-glucosamine, and all except mannose were reduced in concentration in the isogenic mutant. The Δ
cpsD
mutants were highly attenuated in vivo in a hybrid striped bass infection challenge despite being more adherent and invasive to fish epithelial cells and more resistant to cationic antimicrobial peptides than wild-type
S. iniae
. Increased susceptibility of the
S. iniae
Δ
cpsD
mutants to phagocytic killing in whole fish blood and by a fish macrophage cell line confirmed the role of capsule in virulence and highlighted its antiphagocytic function. In summary, we report a genetically defined study on the role of capsule in
S. iniae
virulence and provide preliminary analysis of
S. iniae
capsular polysaccharide sugar components.
Analysis of the Amino Acid Sequence Specificity Determinants of the Enterococcal cCF10 Sex Pheromone in Interactions with the Pheromone-Sensing Machinery
Authors: Fixen Kathryn R. , Chandler Josephine R. , Le Thinh , Kozlowicz Briana K. , Manias Dawn A. , Dunny Gary M.
Published: November 2006

The level of expression of conjugation genes inEnterococcus faecalisstrains carrying the pheromone-responsive transferable plasmid pCF10 is determined by the ratio in the culture medium of two types of signaling peptides, a pheromone (cCF10) and an inhibitor (iCF10). Recent data have demonstrated that both peptides target the cytoplasmic receptor protein PrgX. However, the relative importance of the interaction of these peptides with the pCF10 protein PrgZ (which enhances import of cCF10) versus PrgX is not fully understood, and there is relatively little information about specific amino acid sequence determinants affecting the functional interactions of cCF10 with these proteins in vivo. To address these issues, we used a pheromone-inducible reporter gene system where various combinations of PrgX and PrgZ could be expressed in an isogenic host background to examine the biological activities of cCF10, iCF10, and variants of cCF10 isolated in a genetic screen. The results suggest that most of the amino acid sequence determinants of cCF10 pheromone activity affect interactions between the peptide and PrgX, although some sequence variants that affected peptide/PrgZ interactions were also identified. The results provide functional data to complement ongoing structural studies of PrgX and increase our understanding of the functional interactions of cCF10 and iCF10 with the pheromone-sensing machinery of pCF10.
Cardiac metastases
Authors: Bussani R , De-Giorgio F , Abbate A , Silvestri F
Published: November 2006

Tumours metastatic to the heart (cardiac metastases) are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Although primary cardiac tumours are extremely uncommon (various postmortem studies report rates between 0.001% and 0.28%), secondary tumours are not, and at least in theory, the heart can be metastasised by any malignant neoplasm able to spread to distant sites. In general, cardiac metastases are considered to be rare; however, when sought for, the incidence seems to be not as low as expected, ranging from 2.3% and 18.3%. Although no malignant tumours are known that diffuse preferentially to the heart, some do involve the heart more often than others—for example, melanoma and mediastinal primary tumours. This paper attempts to review the pathophysiology of cardiac metastatic disease, epidemiology and clinical presentation of cardiac metastases, and pathological characterisation of the lesions.
Generalised convulsive status epilepticus: an overview
Authors: Nandhagopal R
Published: November 2006

Generalised convulsive status epilepticus is one of the most common emergencies encountered in clinical practice. This review discusses the recent understanding of this life-threatening condition with reference to the definition, pathophysiology, evaluation, complications, refractory status and prognosis. Besides epilepsy, other neurological and medical illnesses could be associated with status epilepticus. The goals of management and pharmacological approach are outlined, considering the available evidence. Prompt recognition and timely intervention, including pre-hospital treatment, are therapeutically beneficial. Refractory status should be managed in intensive care units under close monitoring. More evidence is needed for evolving the optimal treatment. A suitable treatment protocol would guide in avoiding the pitfalls at various points along the management pathway.
Antibiotic prescription for patients referred to a specialist breast clinic
Authors: Twine C , Gateley C A
Published: November 2006

Hospital referral is indicated as an emergency for breast infections not settling with oral antibiotics. Referrals to a breast clinic over a period of 6 months were assessed for prior antibiotic prescription. A total of 1078 patients were seen during this period. 91 (8%) patients had been prescribed antibiotics, 71% of which had been prescribed for non-infective conditions. Of those patients treated for infection, 42% had the wrong antibiotic prescribed. The final diagnoses for patients inappropriately prescribed antibiotics were chest wall pain in 23% and duct ectasia in 14%. Although the reasons for prescription of antibiotics are mutifactorial, careful examination of the patient will diagnose chest wall pain. Delayed prescribing may be appropriate for some patients.
Varicella vaccination in children with lymphoma and solid tumours
Authors: Emir S , Büyükpamukçu M , Köseoğlu V , Hasçelik G , Akyüz C , Kutluk T , Varan A
Published: November 2006

Background

Varicella infection can be a severe disease, especially in immunosuppressed patients. Here, experience with live varicella vaccine to prevent varicella infection is reported in children who were undergoing treatment for lymphoma and solid tumours.

Methods

40 children, aged between 12 months and 15 years with no clinical history of varicella, were vaccinated with live varicella vaccine. All received two doses of the vaccine subcutaneously 4 weeks apart. Serum samples were taken before the first dose and 6 weeks after the second dose of vaccine.

Results

Before vaccination, 32 patients were seronegative for varicella and eight were seropositive. Seroconversion was observed 6 weeks after the second dose in 24 of the 32 (75%) seronegative children. In 4 of 8 previously seropositive patients, antibody titres increased after immunisation. Zoster infection occurred 5 weeks after the second dose of vaccine in only one previously seronegative child. 7 children, who had responded to the vaccine, have been exposed to varicella in their families or in school without contracting clinical disease.

Conclusion

Although the small number of patients in our group prevents us from drawing definitive conclusions, the varicella vaccine seems to be well tolerated and can be administered to children with lymphoma and solid tumours undergoing treatment.
KNOTS, SATELLITE OPERATIONS AND INVARIANTS OF FINITE ORDER
Authors: PLACHTA L.
Published: November 2006

Let sQ be the satellite operation on knots defined by a pattern (V, Q), where V is a standard solid torus in S3 and Q ⊂ V is a knot that is geometrically essential in V. It is known (Kuperberg [5]) that if v is any knot invariant of order n ≥ 0, then v ◦ sQ is also a knot invariant of order ≤ n. We show that if the knot Q has the winding number zero in V, then the satellite map [Formula: see text] passes n-equivalent knots into (n + 1)-equivalent ones. Kalfagianni [4] has defined for each nonnegative integer n surgery n-trivial knots and studied their properties. It is known that for each n every surgery n-trivial knot is n-trivial. We show that for each n there are n-trivial knots which do not admit a non-unitary n-trivializer that show they to be surgery n-trivial. Przytycki showed [12] that if a knot Q is trivial in S3 and is embedded in V in such a way that it is k-trivial inside V and if a knot [Formula: see text] is m-trivial, then the satellite knot [Formula: see text] is (k + m + 1)-trivial. We establish a version of aforementioned Przytycki's result for surgery n-triviality, refining thus a construction for surgery n-trivial knots suggested by Kalfagianni.
Caveolin-1 abolishment attenuates the myogenic response in murine cerebral arteries
Authors: Adebiyi Adebowale , Zhao Guiling , Cheranov Sergey Y. , Ahmed Abu , Jaggar Jonathan H.
Published: November 2006

Intravascular pressure-induced vasoconstriction (the “myogenic response”) is intrinsic to smooth muscle cells, but mechanisms that underlie this response are unresolved. Here we investigated the physiological function of arterial smooth muscle cell caveolae in mediating the myogenic response. Since caveolin-1 (cav-1) ablation abolishes caveolae formation in arterial smooth muscle cells, myogenic mechanisms were compared in cerebral arteries from control (cav-1+/+) and cav-1-deficient (cav-1−/−) mice. At low intravascular pressure (10 mmHg), wall membrane potential, intracellular calcium concentration ([Ca2+]i), and myogenic tone were similar in cav-1+/+and cav-1−/−arteries. In contrast, pressure elevations to between 30 and 70 mmHg induced a smaller depolarization, [Ca2+]ielevation, and myogenic response in cav-1−/−arteries. Depolarization induced by 60 mM K+also produced an attenuated [Ca2+]ielevation and constriction in cav-1−/−arteries, whereas extracellular Ca2+removal and diltiazem, an L-type Ca2+channel blocker, similarly dilated cav-1+/+and cav-1−/−arteries. Nω-nitro-l-arginine, an nitric oxide synthase inhibitor, did not restore myogenic tone in cav-1−/−arteries. Iberiotoxin, a selective Ca2+-activated K+(KCa) channel blocker, induced a similar depolarization and constriction in pressurized cav-1+/+and cav-1−/−arteries. Since pressurized cav-1−/−arteries are more hyperpolarized and this effect would reduce KCacurrent, these data suggest that cav-1 ablation leads to functional KCachannel activation, an effect that should contribute to the attenuated myogenic constriction. In summary, data indicate that cav-1 ablation reduces pressure-induced depolarization and depolarization-induced Ca2+influx, and these effects combine to produce a diminished arterial wall [Ca2+]ielevation and constriction.
Acute intermittent hypoxia activates myocardial cell survival signaling
Authors: Park Ah-Mee , Nagase Hiroko , Vinod Kumar Shilpashree , Suzuki Yuichiro J.
Published: November 2006

Intermittent hypoxia (IH) with repeated episodes of hypoxia-normoxia cycle has been shown to exert preconditioning-like cardioprotective effects. To understand the mechanism of these events, we investigated the changes in cardiac gene expression in response to acute IH. Mice were subjected to five cycles of 2 min of 10% O2 plus 2 min of 21% O2. RNA was isolated, and gene array analysis was performed. Results show that the expression of antiapoptotic genes, such as Bcl-2 and Bcl-xL, were increased after acute IH. GATA-4 regulates transcription of these genes, and, consistently, GATA-4 activity was increased by acute IH. Although the phosphorylation of GATA-4 has been shown to regulate its activity, no changes in GATA-4 phosphorylation status by acute IH were noted. Gene transcription of gata4 was increased by acute IH, and this might be responsible for the enhanced GATA activity. To understand the mechanism of acute IH activation of gata4 gene transcription, we identified a promoter region of the mouse gata4 gene that is 1,000 bp immediately upstream from the transcriptional start site. In cardiac muscle cells, truncation of 1,000 to 250 bp did not alter the transcriptional activity, suggesting that the proximal 250-bp region contains important transcriptional regulatory sites. We further found that acute IH activates factors which bind to the proximal 100-bp region. Thus acute IH activates not yet identified factors that bind to the proximal 100-bp region of the gata4 promoter and, in turn, increases gata4 gene transcription, leading to enhanced expression of Bcl-2 and Bcl-xL.