bluuebunny/crossref_metadata_2025 huggingface dataset:
Amnion graft following hysteroscopic lysis of intrauterine adhesions
Authors: Amer Mohamed I. , Abd‐El‐Maeboud Karim H.
Published: November 2006

Aim:  To evaluate the safety and efficacy of amnion grafting after hysteroscopic lysis of intrauterine adhesions.

Methods:  In a pilot study involving 25 patients with moderate or severe intrauterine adhesions, hysteroscopic adhesiolysis was followed by intrauterine application of a fresh amnion graft over an inflated balloon of a Foley’s catheter for 2 weeks. Follow‐up hysteroscopy was performed after 4 months. Outcome measures included recurrence of adhesions, achievement of normal menstrual flow, and improvement in the uterine length.

Results:  Moderate (group A) and severe (group B) adhesions were found in 12 and 13 subjects, respectively. Uterine perforation occurred in two patients in group B, one treated conservatively and the other via laparoscopy. No clinical evidence of infection was observed, and spontaneous expulsion of the balloon occurred within days in three patients, with easy removal after 2 weeks in the rest of the subjects. Significant improvement in uterine length was found in both groups. Despite improvement, failure to achieve normal menstrual flow was found in 16.7% in group A versus 23.1% in group B. Follow‐up hysteroscopy revealed adhesion reformation in 48%, all belonging to group B, all with minimal adhesions. Moderate adhesions were found in only two subjects with previous tuberculous endometritis.

Conclusion:  Hysteroscopic lysis of intrauterine adhesions with amnion grafting seems to be a promising procedure for decreasing recurrence of adhesions and encouraging endometrial regeneration. Randomized comparative studies are needed to validate its benefits, including reproductive outcome.
Role of salvage cytoreductive surgery in the treatment of patients with recurrent ovarian cancer after platinum‐based chemotherapy
Authors: Matsumoto Aya , Higuchi Toshihiro , Yura Shigeo , Mandai Masaki , Kariya Masatoshi , Takakura Kenji , Fujii Shingo
Published: November 2006

Objectives:  The role of cytoreductive surgery, which is well established in the primary treatment for epithelial ovarian cancer, is controversial in recurrent disease. The aim of this study was to assess the clinical benefit of salvage surgical cytoreduction in patients with recurrent ovarian cancer after platinum‐based chemotherapy.

Methods:  We conducted a retrospective analysis of 46 patients with recurrent epithelial ovarian cancer treated at our department between 1988 and 2003. Twenty‐three patients underwent salvage cytoreductive surgery (cytoreductive group), and the other 23 patients were treated without surgery (control group).

Results:  Patients in cytoreductive group had a median survival of 41.7 months after recurrence, which was significantly longer than control group (18.8 months; P < 0.01). The duration of stay at home and the period oral intake was preserved were significantly longer in the cytoreductive group. In the cytoreductive group, survival was influenced by the residual disease after surgery (residual tumor diameter, <2 cm vs >2 cm; median survival, 50 months vs 35.2 months; P < 0.05). However, the number of recurrent sites (solitary vs multiple) and the lengths of treatment‐free intervals after primary treatment (<6 months vs >6 months) showed no significant influence on survival.

Conclusions:  The application of cytoreductive surgery might improve the prognosis of patients with recurrent ovarian cancer if the tumor was resectable. Preserved prognoses of platinum‐resistant disease with short treatment‐free interval demonstrated in this study suggest that the concept of maximum cytoreduction might be introduced in the treatment of recurrent disease in the future.
Glycaemic status and cardiovascular disease in type 2 diabetes mellitus: re‐visiting glycated haemoglobin targets for cardiovascular disease prevention
Authors: Golden Sherita H. , Selvin Elizabeth , Cunningham Kayla E.
Published: November 2006

Cardiovascular disease (CVD) is the leading cause of death among people with type 2 diabetes. Recent attention has focused on chronic hyperglycaemia as an additional risk factor in people with diabetes since their excess CVD risk is not entirely explained by traditional cardiovascular risk factors. Clinical trials of intensive glucose control to reduce CVD events have been equivocal, but recent epidemiological studies have shown that HbAlc, a measure of chronic hyperglycaemia, predicts incident cardiovascular events. This review, which focuses on type 2 diabetes, summarizes (i) the epidemiological literature examining the relation between glycaemic status, as assessed by glycated haemoglobin (HbAlc) and CVD, (ii) the controversy regarding treatment goals for HbAlc in terms of preventing microvascular disease vs. macrovascular disease and (iii) on‐going clinical trials of intensive glycaemic control for CVD prevention.
Hardworking Newcomers and Generations of Poverty: Poverty Discourse in Central Washington State
Authors: Devine Jennifer
Published: November 2006

This research is part of a project that aims to reinterpret geographies of poverty in the American Northwest by focusing on the intersections of cultural and political–economic processes that produce poverty differences. This paper contributes to this aim by unpacking poverty beliefs by race at the local county level. This qualitative analysis is grounded in a brief discussion of the political economy of Kittitas County in Central Washington State, which provides space to analyze the theoretical linkages between structural and cultural constructions of poverty differences. Specifically, this paper argues that first generation “hardworking” Hispanic immigrants embody the “working poor”, while individual explanations of poverty are articulated as the “intergenerational poor”, who are racialized as white and choose poverty as a lifestyle. In this vein, many local residents use the marker of “generation” to distinguish between white, lower class individuals who choose to be poor from a group of Hispanic newcomers whose poverty stems from structural forces such as non‐living‐wage jobs and discrimination. This forms one part of a larger strategy to “blame the individual” for the existence of white poverty. This analysis poses new theoretical insights into the intersection between difference markers such as race, class, and generation and contributes to the literature on racial differences in poverty explanations. The geographical specificity of poverty discourse argues for further grounding of the poverty literature in material conditions, which will allow for more nuanced understanding of the creation and persistence of poverty in poor communities.
Impact of Hostility and Withdrawal in Interparental Conflict on Parental Emotional Unavailability and Children's Adjustment Difficulties
Authors: Sturge‐Apple Melissa L. , Davies Patrick T. , Cummings E. Mark
Published: November 2006

This multimethod, prospective study examined the nature of pathways between interparental hostility and withdrawal, parental emotional unavailability, and subsequent changes in children's internalizing and externalizing behaviors, and school adjustment difficulties over a 3‐year period in a sample of 210 mothers, fathers, and 6‐year‐old children. The results of autoregressive structural equation models indicated that interparental withdrawal had a detrimental impact on all areas of children's adjustment, whereas interparental hostility had an indirect effect on subsequent changes in child adjustment. An intermediary role of parental emotional unavailability in links between interparental withdrawal and hostility and child outcomes was indicated, with specific, differential effects observed for fathers and mothers.
How Siblings Resolve Their Conflicts: The Importance of First Offers, Planning, and Limited Opposition
Authors: Ross Hildy , Ross Michael , Stein Nancy , Trabasso Tom
Published: November 2006

Sixty‐four sibling dyads (4–12 years old; 61% males; 83% European‐American) were asked to resolve an ongoing conflict. Older siblings provided leadership by suggesting, modifying, justifying, and requesting assent to plans for conflict resolution. Younger siblings countered and disagreed, but also contributed to planning and agreed to their siblings' plans. Compromises were associated with first offers that met both children's goals, future‐oriented planning, and limited opposition. Win–loss outcomes followed offers favoring only one child and arguments over older siblings' plans. Conflicts were unresolved when negotiations included frequent accusations and opposition, but little planning. Thus mutually beneficial conflict resolution required that children shift focus from debating past wrongs to developing plans to meet their unrealized goals in future interaction.
Effects of Context on Judgments Concerning the Reality Status of Novel Entities
Authors: Woolley Jacqueline D. , Van Reet Jennifer
Published: November 2006

Three studies examined the effects of context on decisions about the reality status of novel entities. In Experiment 1 (144, 3‐ to 5‐year‐olds), participants less often claimed that novel entities were real when they were introduced in a fantastical than in a scientific context. Experiment 2 (61, 4‐ to 5‐year‐olds) revealed that defining novel entities with reference to scientific entities had a stronger effect on reality status judgments than did hearing scientifically oriented stories before encountering the novel entities. The results from Experiment 3 (192, 3‐ to 6‐year‐olds) indicated that definitions that support inferences facilitate reality status judgments more than do definitions that simply associate novel and familiar entities. These findings demonstrate that children share with adults an important means of assessing reality status.
Relations of Maternal Style and Child Self‐Concept to Autobiographical Memories in Chinese, Chinese Immigrant, and European American 3‐Year‐Olds
Authors: Wang Qi
Published: November 2006

The relations of maternal reminiscing style and child self‐concept to children's shared and independent autobiographical memories were examined in a sample of 189 three‐year‐olds and their mothers from Chinese families in China, first‐generation Chinese immigrant families in the United States, and European American families. Mothers shared memories with their children and completed questionnaires; children recounted autobiographical events and described themselves with a researcher. Independent of culture, gender, child age, and language skills, maternal elaborations and evaluations were associated with children's shared memory reports, and maternal evaluations and child agentic self‐focus were associated with children's independent memory reports. Maternal style and child self‐concept further mediated cultural influences on children's memory. The findings provide insight into the social–cultural construction of autobiographical memory.
Corneal Graft and Cataract Surgery in Patients with Moderate to Severe Intellectual Disability
Authors: Cooke C. A. , Frazer D. G. , Jackson A. J.
Published: November 2006

Background Intraocular surgery in patients with intellectual disability can be hazardous. Our aim was to determine the outcomes of surgery on all such patients seen in a consultant‐led service, and to assess the overall risks and benefits.

Materials and Methods A retrospective chart review of patients with moderate to severe intellectual disability, operated upon over a 9‐year period was undertaken. Thirty‐four eyes of 21 patients were operated upon and procedures included four penetrating keratoplasties, five combined penetrating keratoplasties with cataract extractions, and 25 cataract extractions alone.

Results Most patients achieved a beneficial outcome, noted by their carers, such as better mobility and social interaction. Three patients had major post‐operative complications, all associated with corneal grafts. Only seven patients were, within the context of conventional busy outpatient clinics, deemed capable of co‐operating with a formal visual acuity assessment either pre‐ or post‐operatively.

Conclusions Cataract and corneal graft surgery in individuals with intellectual disability is beneficial, and referral to an ophthalmologist should be considered as intellectual disability need not necessarily be a contraindication for surgery. The authors recommend that these patients should be assessed in a dedicated ophthalmology clinic setting for the intellectually disabled, where there should be better facilities for appropriate visual assessment tailored to the patients’ abilities.
Service Use and Costs of Support 12 Years after Leaving Hospital
Authors: Hallam Angela , Beecham Jennifer , Knapp Martin , Carpenter John , Cambridge Paul , Forrester‐Jones Rachel , Tate Alison , Coolen‐Schrijner Pauline , Wooff David
Published: November 2006

Background  There have been major changes in the provision and organization of services for people with intellectual disabilities in England over the last 30 years, particularly deinstitutionalization and the development of the mixed economy of care. The experiences of the people who participated in the Care in the Community Demonstration Programme in the mid‐1980s provide evidence of the immediate and longer‐term effects of the reprovision policy.

Methods  Cross‐sectional and longitudinal evidence was gathered on service use and costs for over 250 people 12 years after they left long‐stay hospitals for community living arrangements. Comparisons were made with the situation in hospital, and 1 and 5 years after leaving. Relationships between costs after 12 years and individual characteristics assessed before people left hospital were explored.

Results  Community care at the 12‐year follow‐up remained more expensive than hospital‐based support, although the average cost was lower than at either of the 1‐ or 5‐year community follow‐up points. Service users were living in a wide variety of accommodation settings. Management responsibility fell on National Health Service (NHS) trusts, local authorities, voluntary agencies, or to private organizations or individuals. After standardizing for users’ skills and abilities, costs in minimum support accommodation were significantly lower than those in residential and nursing homes, costs in staffed group homes significantly higher, and costs in hostels slightly lower. When looking at differences between individuals, no relationship was found between costs and outcomes although, overall, people were better off in the community than they had been when in hospital.

Conclusions  Reprovision planning for hospital and other institutional modes of care requires major and long‐term commitment of resources. Quality of life improvements can be achieved at a cost little different in the long‐run from that for hospital care. The link between needs and costs (reflecting the services intended to meet those needs) would be made stronger through the individualization of care.
A panel of microsatellite markers to study sperm precedence patterns in the emperor dragonfly Anax imperator (Odonata: Anisoptera)
Authors: HADRYS HEIKE , TIMM JANNE , STREIT BRUNO , GIERE SANDRA
Published: November 2006

Odonates were the first group of organisms where sperm competition and last male sperm precedence have been identified. With the development of 10 microsatellites for the emperor dragonfly Anax imperator, the function and priority patterns of the multiple sperm storage organs of females can be studied and compared between species in natural populations. In addition, two microsatellite loci developed for the sister species Anax parthenope, are also highly polymorphic in A. imperator. For the presented 12 microsatellite loci, the number of alleles per locus ranged from two to 24. Observed heterozygosity ranged from 0.07 to 0.88.
Ultrasound and clinical predictors for Caesarean delivery after labour induction at term
Authors: TAN Peng Chiong , SUGUNA Subramaniam , VALLIKKANNU Narayanan , HASSAN Jamiyah
Published: November 2006

Objective:  To assess the relationship of ultrasound assessment for amniotic fluid, fetal weight, cervical length, cervical funneling and clinical factors on the risk of Caesarean delivery after labour induction at term.

Methods:  On hundred and fifty‐two women scheduled for labour induction at term agreed to participate. Sonography was performed to obtain fetal biometry, amniotic fluid index and cervical length and to detect funneling at the internal cervical os. The sonographic findings were concealed. Study women received standard care during labour induction.

Results:  On univariate analysis using Fisher's exact test, parity, cervical length and Bishop score were associated with Caesarean delivery. Following multivariable logistic regression analysis, only nulliparity (adjusted odds ratio (AOR) 5.2 (95% CI 2.2–12.2): P < 0.001) and transvaginal ultrasound‐determined cervical length of more than 20 mm (AOR 2.8 (95% CI 1.0–7.4): P = 0.04) were independent predictors of Caesarean delivery in labour induction. Maternal age, maternal height, gestational age, indication for labour induction, amniotic fluid index, cervical funneling and ultrasound‐estimated fetal weight did not predict Caesarean delivery.

Conclusion:  In women who had undergone labour induction at term with a singleton fetus, nulliparity and cervical length of more than 20 mm on transvaginal sonography were independent predictors of Caesarean delivery. This information is helpful for pre‐induction counselling.
Citron Kinase, a RhoA Effector, Enhances HIV‐1 Virion Production by Modulating Exocytosis
Authors: Loomis Rebecca J. , Holmes Derek A. , Elms Andrew , Solski Patricia A. , Der Channing J. , Su Lishan
Published: November 2006

RhoGTPases play important roles in the regulation of protein transport and membrane recycling. Little is known, however, about how RhoGTPases affect HIV‐1 virion production, which is dependent on the endosomal sorting pathway. We report that ectopic expression of citron kinase (citron‐K), a RhoA effector, preferentially enhances HIV‐1 virion production. Depletion of endogenous citron‐K inhibits HIV‐1 virion production. Citron‐N, which lacks the kinase domain, also enhances HIV‐1 virion production. The leucine zipper, Rho‐binding and zinc finger domains of citron‐N are necessary for the enhancement activity. Citron‐K also enhances murine leukemia virion production and the HIV‐1 late domain is not required for the citron‐K‐mediated enhancement. Ectopic expression of citron‐K leads to the formation of cytoplasmic structures containing citron‐K and HIV‐1 Gag proteins. HIV‐1 and citron‐K cooperatively enhance acidic endosome and lysosome compartments. Finally, citron‐K promotes exocytosis of microvesicles or exosomes that co‐purify with HIV‐1 virions. We conclude that citron‐K enhances HIV‐1 virion production by stimulating the endosomal compartments and exocytosis.
Fractional Brownian motion and the halo mass function
Authors: Pan Jun
Published: November 2006

Fractional Brownian motion with index α is introduced to construct the fractional excursion set model. A new mass function with single parameter α is derived within the formalism, of which the Press–Schechter (PS) mass function is a special case when α= 1/2. Although the new mass function is computed assuming spherical collapse, comparison with the Sheth–Tormen (ST) fitting function shows that the new mass function of α≈ 0.435 agrees with the ST function remarkably well in the high-mass regime, while it predicts more low-mass haloes than the ST function but less than the PS function. The index α is the Hurst exponent, the exact value of which in the context of structure formation is modulated by properties of the smoothing window function and the shape of the power spectrum. It is conjectured that the halo merging rate and merging history in the fractional set theory might be imprinted with the interplay between haloes at small scales and their large-scale environment. Also, the mass function in the high-mass regime can be a good tool to detect the non-Gaussianity of the initial density fluctuation.
A Chemical Genetic Screen for Cell Cycle Inhibitors in Zebrafish Embryos
Authors: Murphey Ryan D. , Stern Howard M. , Straub Christian T. , Zon Leonard I.
Published: November 2006

Chemical genetic screening is an effective strategy to identify compounds that alter a specific biological phenotype. As a complement to cell line screens, multicellular organism screens may reveal additional compounds. The zebrafish embryo is ideal for small molecule studies because of its small size and the ease of waterborne treatment. We first examined a broad range of known cell cycle compounds in embryos using the mitotic marker phospho‐histone H3. The majority of the known compounds exhibited the predicted cell cycle effect in embryos. To determine whether we could identify novel compounds, we screened a 16 320‐compound library for alterations of pH3. This screen revealed 14 compounds that had not been previously identified as having cell cycle activity despite numerous mitotic screens of the same library with mammalian cell lines. With six of the novel compounds, sensitivity was greater in embryos than cell lines, but activity was still detected in cell lines at higher doses. One compound had activity in zebrafish embryos and cell lines but not in mammalian cell lines. The remaining compounds exhibited activity only in embryos. These findings demonstrate that small molecule screens in zebrafish can identify compounds with novel activity and thus may be useful tools for chemical genetics and drug discovery.
Role of recombinant activated factor VII as hemostatic support in orthopedic surgery
Authors: INGERSLEV JØRGEN , SØRENSEN BENNY
Published: November 2006

The purpose of this overview is to collect available literature on the use of recombinant activated factor VII (rFVIIa) in conjunction with orthopedic surgery, and to describe and discuss the efficacy of rFVIIa in such procedures. The review deals with surgical procedures carried out in patients with hemophilia complicated by the presence of inhibitors (alloantibodies) against the missing coagulation factor as well as procedures carried out in persons with no pre‐existing coagulation disorder. One randomized controlled clinical trial has been performed in hemophilia patients with inhibitors, but no other controlled studies were identified. Data collected show that rFVIIa is highly efficacious in the prevention and management of surgical bleeds in most hemophilia patients with inhibitors when frequent bolus injections of 100 µg/kg body weight of rFVIIa was adopted, while data from cases managed with a continuous infusion technology were less clear. In particular, the optimal infusion rate of rFVIIa needs clarification. In orthopedic patients with no known pre‐existing coagulation disorder, data gathered during the review show that rFVIIa reduces the blood loss in severe blunt trauma, while the effect on bleeding by rFVIIa in elective orthopedic procedures needs further clarification.
The use of recombinant activated factor VII in pediatric coagulation disorders
Authors: HANRAHAN JEFFERY , MATHEW PRASAD
Published: November 2006

Recombinant activated factor VII (rFVIIa) is one of the mainstays of treatment in hemophilia patients with inhibitors to factor VIII or IX, and has been a boon to such patients in the management of acute clinical bleeding situations, as prophylaxis for surgical procedures and also in the treatment of life‐ or limb‐threatening bleeding. Given its efficacy in achieving hemostasis in hemophilia, rFVIIa has found its way in the management of non‐hemophilia‐associated bleeding situations, including use in children, where it has been found to be efficacious in a variety of bleeding conditions associated with congenital factor VII deficiency, qualitative platelet defects, in profuse bleeding associated with liver disorders, coagulopathy, and in bleeding triggered by surgery or trauma. However, randomized trials in children using rFVIIa are lacking, and post‐marketing surveillance for adverse effects in the off‐label uses in children is needed. To capture such off‐label uses in children, a registry has been set up through the International Society of Thrombosis and Haemostasis.
Corticomotor excitability contributes to neuromuscular fatigue following marathon running in man
Authors: Ross Emma Z. , Middleton Natalie , Shave Rob , George Keith , Nowicky Alex
Published: November 2006

It is unknown whether changes in corticomotor excitability follow prolonged exercise in healthy humans. Furthermore, the role of supraspinal fatigue in decrements of force production and voluntary activation following prolonged exercise has not been established. This study investigated peripheral and central fatigue after a marathon (42.2 km) on a treadmill. Isometric ankle dorsiflexion force and electromyographic responses of the tibialis anterior in response to magnetic stimulation of the peroneal nerve (PNMS) and the motor cortex (TMS) were measured before, immediately after, 4 and 24 h post‐marathon (MAR) in nine volunteers (mean ±s.d. completion time, 208 ± 22 min). Maximal voluntary contraction decreased by 18 ± 7% immediately after MAR (P= 0.009) and remained significantly decreased after 4 h. The amplitude of the evoked response to TMS, but not to PNMS, was depressed immediately post‐MAR by 57 ± 25% (P= 0.04). Potentiated resting twitch force was reduced in response to both TMS and PNMS post‐MAR (71 ± 8 and 35 ± 2% decrease, P= 0.035 and 0.037, respectively), and voluntary activation was reduced to 61.9 ± 18% immediately post‐MAR (P < 0.05). All measures had returned to baseline values after 24 h. These results suggest that fatigue was attributable to both a disturbance of the contractile apparatus within the muscle and submaximal output from the motor cortex.
Growth Phase-Dependent Effect of Clindamycin on Production of Exoproteins by
Streptococcus pyogenes
Authors: Sawai Jun , Hasegawa Tadao , Kamimura Takuya , Okamoto Akira , Ohmori Daisuke , Nosaka Nobuyuki , Yamada Keiko , Torii Keizo , Ohta Michio
Published: November 2006

The administration of high-dose clindamycin plus benzylpenicillin has been recommended for the treatment of streptococcal toxic shock-like syndrome caused by
Streptococcus pyogenes
, and clindamycin has been found to be more effective than beta-lactams in retrospective analyses of human cases. Although therapeutic doses of clindamycin have also been shown to be effective against experimental infections and clindamycin has great efficacy against the production of bacterial exoproteins, we recently reported that the level of production of some exoproteins was unchanged or even increased by a subinhibitory dose of clindamycin when it is added upon the initiation of bacterial culture and the treated cultures were analyzed by two-dimensional gel electrophoresis. In this study we further examined the effect of clindamycin on the production of exoproteins by adding it to
Streptococcus pyogenes
cultures during various growth phases. We found that the levels of production of some proteins, NAD
+
glycohydrolase, streptolysin O, and streptococcal inhibitor of complement, were increased when clindamycin was added at early-log-phase growth, which was the result that was seen when clindamycin was added at the beginning of culture. However, clindamycin inhibited the production of most types of proteins when it was administered to
Streptococcus pyogenes
cultures at mid-log-phase growth. In
csrS
- or
mga
-knockout bacterial strains, the increase in exoproteins seen in parental strains was considerably inhibited. Our study indicates that the in vitro effect of clindamycin on the production of exoproteins greatly depends on the growth phase of bacteria and some regulatory factors of
Streptococcus pyogenes
that are involved in this phenomenon.
Activities of Antimicrobial Peptides and Synergy with Enrofloxacin against
Mycoplasma pulmonis
Authors: Fassi Fehri Lina , Wróblewski Henri , Blanchard Alain
Published: November 2006

We showed in a previous study that associations of antimicrobial peptides (AMPs), which are key components of the innate immune systems of all living species, with the fluoroquinolone enrofloxacin can successfully cure HeLa cell cultures of
Mycoplasma fermentans
and
M. hyorhinis
contamination. In the present work, the in vitro susceptibility of
M. pulmonis
, a murine pathogen, to enrofloxacin and four AMPs (alamethicin, globomycin, gramicidin S, and surfactin) was investigated, with special reference to synergistic associations and the effect of the mycoplasma cell concentration. Enrofloxacin and globomycin displayed the lowest MICs (0.4 μM), followed by gramicidin S (3.12 μM), alamethicin (6.25 μM), and surfactin (25 μM). When the mycoplasma cell concentration was varied from 10
4
to 10
8
CFU/ml, the MICs of enrofloxacin and globomycin increased while those of the three other molecules remained essentially constant. The minimal bactericidal concentration of enrofloxacin (0.8 μM) was also lower than those of the peptides (6.25 to 100 μM), but the latter killed the mycoplasma cells much faster than enrofloxacin (2 h versus 1 day). The use of the AMPs in association with enrofloxacin revealed synergistic effects with alamethicin and surfactin. Interestingly, the mycoplasma-killing activities of the two combinations enrofloxacin (MIC/2) plus alamethicin (MIC/4) and enrofloxacin (MIC/2) plus surfactin (MIC/16) were about 2 orders of magnitude higher than those of the three molecules used separately. These results support the interest devoted to AMPs as a novel class of antimicrobial agents and pinpoint their ability to potentiate the activities of conventional antibiotics, such as fluoroquinolones.
Proteolytic Stability of Insecticidal Toxins Expressed in Recombinant Bacilli
Authors: Yang Yankun , Wang Liwei , Gaviria Adelaida , Yuan Zhiming , Berry Colin
Published: November 2006

The production of the vegetative mosquitocidal toxin Mtx1 from
Bacillus sphaericus
was redirected to the sporulation phase by replacement of its weak, native promoter with the strong sporulation promoter of the
bin
genes. Recombinant bacilli developed toxicity during early sporulation, but this declined rapidly in later stages, indicating the proteolytic instability of the toxin. Inhibition studies indicated the action of a serine proteinase, and similar degradation was also seen with the purified
B. sphaericus
enzyme sphericase. Following the identification of the initial cleavage site involved in this degradation, mutant Mtx1 proteins were expressed in an attempt to overcome destructive cleavage while remaining capable of proteolytic activation. However, the apparently broad specificity of sphericase seems to make this impossible. The stability of a further vegetative toxin, Mtx2, was also found to be low when it was exposed to sphericase or conditioned medium. Random mutation of the receptor binding loops of the
Bacillus thuringiensis
Cry1Aa toxin did, in contrast, allow production of significant levels of spore-associated protein in the form of parasporal crystals. The exploitation of vegetative toxins may, therefore, be greatly limited by their susceptibility to proteinases produced by the host bacteria, whereas the sequestration of sporulation-associated toxins into crystals may make them more amenable to use in strain improvement.
Cross-Species GacA-Controlled Induction of Antibiosis in Pseudomonads
Authors: Dubuis Christophe , Haas Dieter
Published: November 2006

Signal extracts prepared from culture supernatants of
Pseudomonas fluorescens
CHA0 and
Pseudomonas aeruginosa
PAO stimulated GacA-dependent expression of small RNAs and hence of antibiotic compounds in both hosts.
Pseudomonas corrugata
LMG2172 and
P. fluorescens
SBW25 also produced signal molecules stimulating GacA-controlled antibiotic synthesis in strain CHA0, illustrating a novel,
N
-acyl-homoserine lactone-independent type of interspecies communication.
Cryptococcal Lipid Metabolism: Phospholipase B1 Is Implicated in Transcellular Metabolism of Macrophage-Derived Lipids
Authors: Wright Lesley C. , Santangelo Rosemary M. , Ganendren Ranjini , Payne Jackie , Djordjevic Julianne T. , Sorrell Tania C.
Published: November 2006

Cryptococci survive and replicate within macrophages and can use exogenous arachidonic acid for the production of eicosanoids. Phospholipase B1 (PLB1) has a putative, but uninvestigated, role in these processes. We have shown that uptake and esterification of radiolabeled arachidonic, palmitic, and oleic acids by the
Cryptococcus neoformans
var.
grubii
H99 wild-type strain and its PLB1 deletion mutant strain (the
Δplb1
strain) are independent of PLB1, except under hyperosmolar stress. Similarly, PLB1 was required for metabolism of 1-palmitoyl lysophosphatidylcholine (LysoPC), which is toxic to eukaryotic cell membranes, under hyperosmolar conditions. During both logarithmic and stationary phases of growth, the physiologically relevant phospholipids, dipalmitoyl phosphatidylcholine (DPPC) and dioleoyl phosphatidylcholine, were taken up and metabolized via PLB1. Exogenous DPPC did not enhance growth in the presence of glucose as a carbon source but could support it for at least 24 h in glucose-free medium. Detoxification of LysoPC by reacylation occurred in both the H99 wild-type and the
Δplb1
strains in the presence of glucose, but PLB1 was required when LysoPC was the sole carbon source. This indicates that both energy-independent (via PLB1) and energy-dependent transacylation pathways are active in cryptococci. Phospholipase A
1
activity was identified by PLB1-independent degradation of 1-palmitoyl-2-arachidonoyl phosphatidylcholine, but the arachidonoyl LysoPC formed was not detoxified by reacylation. Using the human macrophage-like cell line THP-1, we demonstrated the PLB1-dependent incorporation of macrophage-derived arachidonic acid into cryptococcal lipids during cryptococcus-phagocyte interaction. This pool of arachidonate can be sequestered for eicosanoid production by the fungus and/or suppression of host phagocytic activity, thus diminishing the immune response.
Recruitment of Macrophages and Polymorphonuclear Leukocytes in Lyme Carditis
Authors: Montgomery Ruth R. , Booth Carmen J. , Wang Xiaomei , Blaho Victoria A. , Malawista Stephen E. , Brown Charles R.
Published: November 2006

Lyme arthritis, caused by the spirocheteBorrelia burgdorferi, can be recurrent or prolonged, whereas Lyme carditis is mostly nonrecurring. A prominent difference between arthritis and carditis is the differential representation of phagocytes in these lesions: polymorphonuclear leukocytes (PMN) are more prevalent in the joint, and macrophages predominate in the heart lesion. We have previously shown differential efficiency ofB. burgdorfericlearance by PMN and macrophages, and we now investigate whether these functional differences at the cellular level may contribute to the observed differences in organ-specific pathogenesis. When we infected mice lacking the neutrophil chemokine receptor (CXCR2−/−mice) with spirochetes, we detected fewer PMN in joints and less-severe arthritis. Here we have investigated the effects of the absence of the macrophage chemokine receptor CCR2 on the development and resolution of Lyme carditis in resistant (C57BL/6J [B6]) and sensitive (C3H/HeJ [C3H]) strains of mice. In B6 CCR2−/−mice, although inflammation in hearts is mild, we detected an increased burden ofB. burgdorfericompared to that in wild-type (WT) mice, suggesting reduced clearance in the absence of macrophages. In contrast, C3H CCR2−/−mice have severe inflammation but a decreasedB. burgdorferiburden compared to that in WT C3H mice both at peak disease and during resolution. Histopathologic examination of infected hearts revealed that infected C3H CCR2−/−animals have an increased presence of PMN, suggesting compensatory mechanisms ofB. burgdorfericlearance in the hearts of infected C3H CCR2−/−mice. The more efficient clearance ofB. burgdorferifrom hearts by CCR2−/−versus WT C3H mice suggests a natural defect in the recruitment or function of macrophages in C3H mice, which may contribute to the sensitivity of this strain toB. burgdorferiinfection.
Role of the Lipopolysaccharide-CD14 Complex for the Activity of Hemolysin from Uropathogenic
Escherichia coli
Authors: Månsson Lisa E. , Kjäll Peter , Pellett Shahaireen , Nagy Gábor , Welch Rodney A. , Bäckhed Fredrik , Frisan Teresa , Richter-Dahlfors Agneta
Published: November 2006

Bacterial pathogens produce a variety of exotoxins, which often become associated with the bacterial outer membrane component lipopolysaccharide (LPS) during their secretion. LPS is a potent proinflammatory mediator; however, it is not known whether LPS contributes to cell signaling induced by those microbial components to which it is attached. This is partly due to the common view that LPS present in bacterial component preparations is an experimental artifact. The
Escherichia coli
exotoxin hemolysin (Hly) is a known inducer of proinflammatory signaling in epithelial cells, and the signal transduction pathway involves fluctuation of the intracellular-Ca
2+
concentration. Since LPS is known to interact with Hly, we investigated whether it is required as a cofactor for the activity of Hly. We found that the LPS/Hly complex exploits the CD14/LPS-binding protein recognition system to bring Hly to the cell membrane, where intracellular-Ca
2+
signaling is initiated via specific activation of the small GTPase RhoA. Hly-induced Ca
2+
signaling was found to occur independently of the LPS receptor TLR4, suggesting that the role of LPS/CD14 is to deliver Hly to the cell membrane. In contrast, the cytolytic effect triggered by exposure of cells to high Hly concentrations occurs independently of LPS/CD14. Collectively, our data reveal a novel molecular mechanism for toxin delivery in bacterial pathogenesis, where LPS-associated microbial compounds are targeted to the host cell membrane as a consequence of their association with LPS.
Different Roles of the Two High-Oxygen-Affinity Terminal Oxidases of
Brucella suis
: Cytochrome
c
Oxidase, but Not Ubiquinol Oxidase, Is Required for Persistence in Mice
Authors: Jiménez de Bagüés Maria Pilar , Loisel-Meyer Séverine , Liautard Jean-Pierre , Jubier-Maurin Véronique
Published: November 2006

The survival of
Brucella suis
mutant strains in mice demonstrated different roles of the two high-oxygen-affinity terminal oxidases. The
cbb3
-type cytochrome
c
oxidase was essential for chronic infection in oxygen-deficient organs. Lack of the cytochrome
bd
ubiquinol oxidase led to hypervirulence of bacteria, which could rely on nitrite accumulation inhibiting the inducible nitric oxide synthase of the host.
Comparative Analysis of the Abilities of Shiga Toxins 1 and 2 To Bind to and Influence Neutrophil Apoptosis
Authors: Flagler Michael J. , Strasser Jane E. , Chalk Claudia L. , Weiss Alison A.
Published: November 2006

Hemolytic-uremic syndrome (HUS), the life-threatening complication following infection by the intestinal pathogen
Escherichia coli
O157:H7, is due to the ability of the pathogen to produce toxins in the Shiga toxin (Stx) family. Activated neutrophils are observed in HUS patients, yet it is unclear whether Stx exerts a direct effect on neutrophils or whether the toxin acts indirectly. The effect of Stx1 and Stx2 on human neutrophils was examined. Neither Stx1 nor Stx2 altered the rate of neutrophil apoptosis. Minimal binding of either toxin to neutrophils was observed, and the toxin was easily eluted from the cells. Stx1 and Stx2 were found to circulate in the plasma of mice following intravenous injection, and both toxins were cleared rapidly from the blood. Together these results suggest that neither Stx1 nor Stx2 interacts directly with neutrophils.
Identification of the Functional Initiation Codons of a Phase-Variable Gene of
Haemophilus influenzae
,
lic2A
, with the Potential for Differential Expression
Authors: Dixon Kevin , Bayliss Christopher D. , Makepeace Katherine , Moxon E. Richard , Hood Derek W.
Published: November 2006

Simple sequence repeats located within reading frames mediate phase-variable ON/OFF switches in gene expression by generating frameshifts. Multiple translation initiation codons in different reading frames are found upstream of most
Haemophilus influenzae
tetranucleotide repeat tracts, raising the possibility of multiple active reading frames and more than two levels of gene expression for these loci. Phase variation between three levels of gene expression (strong, weak, and none) was observed when
lic2A
was fused to a
lacZ
reporter gene. The
lic2A
5′ CAAT repeat tract is preceded by four 5′ ATG codons (x, y, z1, and z2) in two reading frames. Each of these initiation codons was inactivated by site-directed mutagenesis. Strong expression from frame 1 was associated with x but not y. Weak expression from frame 2 was mainly dependent on the z2 codon, and there was no expression from frame 3. Using monoclonal antibodies specific for a digalactoside epitope of lipopolysaccharide whose synthesis requires Lic2A, two levels (strong and undetectable) of antibody reactivity were detected, suggesting that weak expression of
lic2A
is not discernible at the phenotypic level. Inactivation of the x initiation codon resulted in loss of strong expression of the digalactoside epitope and elevated killing by human serum. The failure to detect more than two phenotypes for
lic2A
, despite clear evidence of weak expression from the z1/z2 initiation codons, leaves open the question of whether or not multiple initiation codons are associated with more complex patterns of phenotypic variation rather than classical phase-variable switching between two phenotypes.
Global Analysis of theMycobacterium tuberculosisZur (FurB) Regulon
Authors: Maciąg Anna , Dainese Elisa , Rodriguez G. Marcela , Milano Anna , Provvedi Roberta , Pasca Maria R. , Smith Issar , Palù Giorgio , Riccardi Giovanna , Manganelli Riccardo
Published: November 2006

The proteins belonging to the Fur family are global regulators of gene expression involved in the response to several environmental stresses and to the maintenance of divalent cation homeostasis. TheMycobacterium tuberculosisgenome encodes two Fur-like proteins, FurA and a protein formerly annotated FurB. Since in this paper we show that it represents a zinc uptake regulator, we refer to it as Zur. The gene encoding Zur is found in an operon together with the gene encoding a second transcriptional regulator (Rv2358). In a previous work we demonstrated that Rv2358 is responsible for the zinc-dependent repression of the Rv2358-zuroperon, favoring the hypothesis that these genes represent key regulators of zinc homeostasis. In this study we generated azurmutant inM. tuberculosis, examined its phenotype, and characterized the Zur regulon by DNA microarray analysis. Thirty-two genes, presumably organized in 16 operons, were found to be upregulated in thezurmutant. Twenty-four of them belonged to eight putative transcriptional units preceded by a conserved 26-bp palindrome. Electrophoretic mobility shift experiments demonstrated that Zur binds to this palindrome in a zinc-dependent manner, suggesting its direct regulation of these genes. The proteins encoded by Zur-regulated genes include a group of ribosomal proteins, three putative metal transporters, the proteins belonging to early secretory antigen target 6 (ESAT-6) cluster 3, and three additional proteins belonging to the ESAT-6/culture filtrate protein 10 (CFP-10) family known to contain immunodominant epitopes in the T-cell response toM. tuberculosisinfection.
Aggregation during Fruiting Body Formation in
Myxococcus xanthus
Is Driven by Reducing Cell Movement
Authors: Sliusarenko Oleksii , Zusman David R. , Oster George
Published: November 2006

When starved,
Myxococcus xanthus
cells assemble themselves into aggregates of about 10
5
cells that grow into complex structures called fruiting bodies, where they later sporulate. Here we present new observations on the velocities of the cells, their orientations, and reversal rates during the early stages of fruiting body formation. Most strikingly, we find that during aggregation, cell velocities slow dramatically and cells orient themselves in parallel inside the aggregates, while later cell orientations are circumferential to the periphery. The slowing of cell velocity, rather than changes in reversal frequency, can account for the accumulation of cells into aggregates. These observations are mimicked by a continuous agent-based computational model that reproduces the early stages of fruiting body formation. We also show, both experimentally and computationally, how changes in reversal frequency controlled by the Frz system mutants affect the shape of these early fruiting bodies.
Identification and Characterization of an RTX Toxin in the Emerging Pathogen
Kingella kingae
Authors: Kehl-Fie Thomas E. , St. Geme Joseph W.
Published: November 2006

Kingella kingae
is an emerging bacterial pathogen that is increasingly recognized as the causative agent of a variety of pediatric diseases, including septic arthritis and osteomyelitis. The pathogenesis of
K. kingae
disease is believed to begin with colonization of the upper respiratory tract. In the present study, we examined interactions between
K. kingae
and cultured respiratory epithelial cells and observed potent cytotoxicity, detected by both microscopy and lactic acid dehydrogenase (LDH) release assays. Experiments with synovial and macrophage cell lines revealed cytotoxicity for these cell types as well. Using mariner mutagenesis and a screen for loss of cytotoxicity, a genetic locus encoding an RTX toxin system was identified. Disruption of the
K. kingae
RTX locus resulted in a loss of cytotoxicity for respiratory epithelial, synovial, and macrophage cell lines. DNA sequence analysis demonstrated that the RTX locus is flanked by insertion elements and has a reduced G+C content compared to that of the whole genome. Two relatively less invasive
Kingella
species,
K. oralis
and
K. denitrificans
, were found to be noncytotoxic and to lack the RTX region, as determined by LDH release assays and Southern blotting. We concluded that
K. kingae
expresses an RTX toxin that has wide cellular specificity and was likely acquired horizontally. The possible roles for this toxin in the pathogenesis of
K. kingae
disease include breaching of the epithelial barrier and destruction of target tissues, such as synovium (joint lining).
The
lspA
Gene, Encoding the Type II Signal Peptidase of
Rickettsia typhi
: Transcriptional and Functional Analysis
Authors: Rahman M. Sayeedur , Ceraul Shane M. , Dreher-Lesnick Sheila M. , Beier Magda S. , Azad Abdu F.
Published: November 2006

Lipoprotein processing by the type II signal peptidase (SPase II) is known to be critical for intracellular growth and virulence for many bacteria, but its role in rickettsiae is unknown. Here, we describe the analysis of
lspA
, encoding a putative SPase II, an essential component of lipoprotein processing in gram-negative bacteria, from
Rickettsia typhi
. Alignment of deduced amino acid sequences shows the presence of highly conserved residues and domains that are essential for SPase II activity in lipoprotein processing. The transcription of
lspA
,
lgt
(encoding prolipoprotein transferase), and
lepB
(encoding type I signal peptidase), monitored by real-time quantitative reverse transcription-PCR, reveals a differential expression pattern during various stages of rickettsial intracellular growth. The higher transcriptional level of all three genes at the preinfection time point indicates that only live and metabolically active rickettsiae are capable of infection and inducing host cell phagocytosis.
lspA
and
lgt
, which are involved in lipoprotein processing, show similar levels of expression. However,
lepB
, which is involved in nonlipoprotein secretion, shows a higher level of expression, suggesting that LepB is the major signal peptidase for protein secretion and supporting our in silico prediction that out of 89 secretory proteins, only 14 are lipoproteins. Overexpression of
R. typhi lspA
in
Escherichia coli
confers increased globomycin resistance, indicating its function as SPase II. In genetic complementation, recombinant
lspA
from
R. typhi
significantly restores the growth of temperature-sensitive
E. coli
Y815 at the nonpermissive temperature, supporting its biological activity as SPase II in prolipoprotein processing.