bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic diversity and differentiation of central European freshwater pearl mussel (Margaritifera margaritifera L.) populations: implications for conservation and management
Authors: GEIST JUERGEN , KUEHN RALPH
Published: January 2005

Despite the fact that mollusc species play an important role in many aquatic ecosystems, little is known about their biodiversity and conservation genetics. Freshwater pearl mussel (Margaritifera margaritifera L.) populations are seriously declining all over Europe and a variety of conservation programs are being established to support the remaining endangered central European populations. In order to provide guidelines for conservation strategies and management programs, we investigated the genetic structure of 24 freshwater pearl mussel populations originating from five major central European drainages including Elbe, Danube, Rhine, Maas and Weser, representing the last and most important populations in this area. We present a nondestructive sampling method of haemolymph for DNA analyses, which is applicable for endangered bivalves. The analyses of nine microsatellite loci with different levels of polymorphism revealed a high degree of fragmented population structure and very different levels of genetic diversity within populations. These patterns can be explained by historical and demographic effects and have been enforced by anthropogenic activities. Even within drainages, distinct conservation units were detected, as revealed from high FST values, private alleles and genetic distance measures. Populations sampled close to contact zones between main drainage systems showed lowest levels of correct assignment to present‐day drainage systems. Populations with high priority for conservation should not only be selected by means of census population size and geographical distance to other populations. Instead, detailed genetic analyses are mandatory for revealing differentiation and diversity parameters, which should be combined with ecological criteria for sustainable conservation and recovery programs.
Patterns of genetic diversity and migration in increasingly fragmented and declining orang‐utan (Pongo pygmaeus) populations from Sabah, Malaysia
Authors: GOOSSENS B. , CHIKHI L. , JALIL M. F. , ANCRENAZ M. , LACKMAN‐ANCRENAZ I. , MOHAMED M. , ANDAU P. , BRUFORD M. W.
Published: January 2005

We investigated the genetic structure within and among Bornean orang‐utans (Pongo pygmaeus) in forest fragments of the Lower Kinabatangan flood plain in Sabah, Malaysia. DNA was extracted from hair and faecal samples for 200 wild individuals collected during boat surveys on the Kinabatangan River. Fourteen microsatellite loci were used to characterize patterns of genetic diversity. We found that genetic diversity was high in the set of samples (mean HE = 0.74) and that genetic differentiation was significant between the samples (average FST = 0.04, P < 0.001) with FST values ranging from low (0.01) to moderately large (0.12) values. Pairwise FST values were significantly higher across the Kinabatangan River than between samples from the same river side, thereby confirming the role of the river as a natural barrier to gene flow. The correlation between genetic and geographical distance was tested by means of a series of Mantel tests based on different measures of geographical distance. We used a Bayesian method to estimate immigration rates. The results indicate that migration is unlikely across the river but cannot be completely ruled out because of the limited FST values. Assignment tests confirm the overall picture that gene flow is limited across the river. We found that migration between samples from the same side of the river had a high probability indicating that orang‐utans used to move relatively freely between neighbouring areas. This strongly suggests that there is a need to maintain migration between isolated forest fragments. This could be done by restoring forest corridors alongside the river banks and between patches.
Microsatellites reveal regional population differentiation and isolation inLobaria pulmonaria, an epiphytic lichen
Authors: WALSER JEAN‐CLAUDE , HOLDEREGGER ROLF , GUGERLI FELIX , HOEBEE SUSAN EVA , SCHEIDEGGER CHRISTOPH
Published: January 2005

Many lichen species produce both sexual and asexual propagules, but, aside from being minute, these diaspores lack special adaptations for long‐distance dispersal. So far, molecular studies have not directly addressed isolation and genetic differentiation of lichen populations, both being affected by gene flow, at a regional scale. We used six mycobiont‐specific microsatellite loci to investigate the population genetic structure of the epiphytic lichenLobaria pulmonariain two regions that strongly differed with respect to anthropogenic impact. In British Columbia,L. pulmonariagrows in continuous old‐growth forests, while its populations in the old cultural landscape of Switzerland are comparably small and fragmented. Populations from both British Columbia and Switzerland were genetically diverse at the loci. Geographically restricted alleles, low historical gene flow, and analyses of genetic distance (upgmatree) and of differentiation (amova) indicated that populations from Vancouver Island and from the Canadian mainland were separated from each other, except for one, geographically intermediate population. This differentiation was attributed to different glacial and postglacial histories of coastal and inland populations in British Columbia. In contrast to expectations, the three investigated Swiss populations were genetically neither isolated nor differentiated from each other despite the long‐lasting negative human impact on the lichen's range size in Central Europe. We propose that detailed studies integrating local landscape and regional scales are now needed to understand the processes of dispersal and gene flow in lichens.
Geographic and phylogenetic evidence for dispersed nuclear introgression in a daphniid with sexual propagules
Authors: TAYLOR DEREK J. , SPRENGER HEATHER L. , ISHIDA SEIJI
Published: January 2005

The role of among‐species gene flow in eukaryotic evolution remains controversial. Putative hybrid lineages are common in water fleas, but their ecological success is often associated with polyploidy and the production of asexual propagules. Advanced hybrid lineages with sexual propagules are expected to be geographically restricted because their successful dispersal is contingent on overcoming fertility complications, assimilation by parent taxa, and competition with parent taxa. Here we provide evidence that a diploid lineage ofDaphniahas been formed by introgression between distantly related species and attained a broad distribution (Nearctic) despite its requirement for sexual propagules. The evidence is based on geographical discordance, phylogenetic discordance, recombinant genotypes and additive genotypes of the nuclear internal transcribed spacer regions (ITS) and mitochondrial DNA. Additive genotypes also provided evidence of hybridization between introduced EuropeanDaphniaand North AmericanDaphnia. We argue that the unique biology of Holarctic lacustrine water fleas and the spatial separation of lineages during Pleistocene glaciation have promoted hybridization and its evolutionary consequences.
High specificity generally characterizes mycorrhizal association in rare lady's slipper orchids, genus Cypripedium
Authors: SHEFFERSON RICHARD P. , WEIß MICHAEL , KULL TIIU , TAYLOR D. LEE
Published: January 2005

Lady's slipper orchids (Cypripedium spp.) are rare terrestrial plants that grow throughout the temperate Northern Hemisphere. Like all orchids, they require mycorrhizal fungi for germination and seedling nutrition. The nutritional relationships of adult Cypripedium mycorrhizae are unclear; however, Cypripedium distribution may be limited by mycorrhizal specificity, whether this specificity occurs only during the seedling stage or carries on into adulthood. We attempted to identify the primary mycorrhizal symbionts for 100 Cypripedium plants, and successfully did so with two Cypripedium calceolus, 10 Cypripedium californicum, six Cypripedium candidum, 16 Cypripedium fasciculatum, two Cypripedium guttatum, 12 Cypripedium montanum, and 11 Cypripedium parviflorum plants from a total of 44 populations in Europe and North America, yielding fungal nuclear large subunit and mitochondrial large subunit sequence and RFLP (restriction fragment length polymorphism) data for 59 plants. Because orchid mycorrhizal fungi are typically observed without fruiting structures, we assessed fungal identity through direct PCR (polymerase chain reaction) amplification of fungal genes from mycorrhizally colonized root tissue. Phylogenetic analysis revealed that the great majority of Cypripedium mycorrhizal fungi are members of narrow clades within the fungal family Tulasnellaceae. Rarely occurring root endophytes include members of the Sebacinaceae, Ceratobasidiaceae, and the ascomycetous genus, Phialophora. C. californicum was the only orchid species with apparently low specificity, as it associated with tulasnelloid, ceratobasidioid, and sebacinoid fungi in roughly equal proportion. Our results add support to the growing literature showing that high specificity is not limited to nonphotosynthetic plants, but also occurs in photosynthetic ones.
Population structure of Columbia spotted frogs (Rana luteiventris) is strongly affected by the landscape
Authors: FUNK W. CHRIS , BLOUIN MICHAEL S. , CORN PAUL STEPHEN , MAXELL BRYCE A. , PILLIOD DAVID S. , AMISH STEPHEN , ALLENDORF FRED W.
Published: January 2005

Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing three questions: (i) do ridges act as barriers to gene flow? (ii) is gene flow restricted between low and high elevation ponds? (iii) does a pond equal a ‘randomly mating population’ (a deme)? We found that mountain ridges and elevational differences were associated with increased genetic differentiation among sites, suggesting that gene flow is restricted by ridges and elevation in this species. We also found that populations of Columbia spotted frogs generally include more than a single pond except for very isolated ponds. There was also evidence for surprisingly high levels of gene flow among low elevation sites separated by large distances. Moreover, genetic variation within populations was strongly negatively correlated with elevation, suggesting effective population sizes are much smaller at high elevation than at low elevation. Our results show that landscape features have a profound effect on patterns of genetic variation in Columbia spotted frogs.
Geographical distance and physical barriers shape the genetic structure of Eurasian red squirrels (Sciurus vulgaris) in the Italian Alps
Authors: TRIZIO I. , CRESTANELLO B. , GALBUSERA P. , WAUTERS L. A. , TOSI G. , MATTHYSEN E. , HAUFFE H. C.
Published: January 2005

Red squirrels (Sciurus vulgaris) are widely distributed throughout Eurasia, occurring in many types of coniferous and mixed‐deciduous forests. In fragmented landscapes, small and partly isolated populations with low immigration rates show reduced genetic diversity, but reforestation can increase gene flow and restore levels of genetic variation in a few decades. No studies have so far investigated the genetic structure of red squirrel in large, continuous forests. The Italian Alps are presently characterized by almost continuous, recently reconnected forest habitats, that were affected by deep landscape changes during last glaciations but remained mostly unchanged between 10 000 and 200 years bp, when forest cover was heavily reduced. In this study we analyse patterns of genetic variability of red squirrels in and between seven sites distributed over 250 km of Alpine habitat, using mitochondrial DNA (mtDNA) and microsatellites. We use isolation‐by‐distance (IBD) models to investigate the relative importance that past (Pleistocene glaciations) and recent (fragmentation, bottlenecks) events had on the present genetic situation. Both nuclear and mtDNA data indicate a significant differentiation among study sites and a significant correlation between genetic and geographical distance only over a large scale. No recent bottlenecks are recorded through microsatellites and demographic models strongly support equilibrium between gene flow and drift; however, mtDNA suggests that there may have been local demographic crashes, probably in correspondence with the 19th‐century forest fragmentation. These findings indicate that local landscape factors other than geographical distance per se, such as barriers of unsuitable habitat, affect gene flow and determine differentiation.
Studies of twins: what can they tell us about the fetal origins of adult disease?
Authors: Morley Ruth , Dwyer Terence
Published: January 2005

There has been much interest in evidence that people with lower birthweight have higher risk of adult cardiovascular disease, but the causal pathways underlying such observations are uncertain. Study of twins offers an opportunity to shed light on the underlying causal pathways, in particular by investigating the role of ‘shared’ factors vs. factors affecting each individual fetus. This involves comparing results of within‐cohort vs. within‐pair analyses.

Twins share many factors during gestation but birthweight discordance (difference in birthweight within a twin pair) cannot be determined by these shared factors and must relate to factors affecting growth of each individual fetus. If associations seen in a cohort of twins remain in within‐pair analyses, then factors specific to each individual must be involved in the underlying causal pathways. Conversely, if the relationships disappear or substantially diminish in within‐pair analyses, then factors common to the pair must be involved. Comparison of findings in monozygotic vs. dizygotic twins may provide insights into the role of genetic factors, although issues related to chorionicity need to be taken into account.

We tabulate published data and conclude that differences in methodology and analyses preclude informative meta‐analysis, and that analysis of pooled data would provide more useful information.
A discussion of some statistical methods for separating within‐pair associations from associations among all twins in research on fetal origins of disease
Authors: Dwyer Terence , Blizzard Leigh
Published: January 2005

Twin data can be used to gain insights into the origin of associations between factors arising in fetal life and the risk of later disease. This is because twin data afford an opportunity to conduct paired analyses that take the influence of shared factors into account. When an association that is present in an unpaired analysis is present also in a paired analysis, there is evidence that the causal pathway linking the fetal factor and the disease may have a fetal origin. If the association disappears in the paired analysis, there is evidence that it may have has arisen from a shared source such as the mother. The relevant factors include diet and socio‐economic status.

There are several statistical approaches to this. The simplest involves comparing, say, a coefficient from a regression of an outcome on a fetal factor for all subjects in a twin sample, with the coefficient obtained from regressing the within‐pair difference in the outcome on the within‐pair difference in the fetal factor. Alternative approaches involve simultaneously estimating regression parameters for between‐ and within‐pair components. These approaches permit similar inferences about whether the association is due to individual (fetal) or shared (maternal) factors, and are valid in the circumstances that non‐shared factors missing from the regression model do not influence the regression estimates.
Basic mechanisms of humoral rejection
Authors: Cascalho Marilia , Platt Jeffrey L.
Published: January 2005

Abstract:  Humoral rejection is among the most vexing problems afflicting organ transplants. Triggered by antibodies predominantly against donor human leukocyte (HLA), humoral rejection can now be understood through consideration of basic mechanisms of immunity to foreign antigens and impact of humoral immunity on blood vessels. Basic considerations may also shed light on mechanisms by which various treatments have recently brought about vastly improved outcomes.
Excellent outcome in infants and small children with thrombophilias undergoing kidney transplantation*
Authors: Dick Andre A. , Lerner Susan M. , Boissy Adrienne R. , Farrell Colleen E. , Alfrey Edward J.
Published: January 2005

Abstract:  One of the most common causes of early graft failure in children undergoing renal transplantation is vascular thrombosis. Numerous risk factors for graft thrombosis have been previously described. Children with various types of thrombophilias such as protein C, protein S and factor V Leiden deficiencies are at an increased risk for vascular thrombosis. Infants and small children with these disorders undergoing renal transplantation have not been well documented in the literature. We reviewed our experience in the diagnosis, peri‐operative management and follow up of these patients at our institution. A retrospective analysis of all children undergoing renal transplantation at our institution, using data obtained from the Pediatric Transplant Registry at our institution since May 2000 was performed. The indications for renal transplant included focal segmental glomerulosclerosis, renal dysplasia and reflux nephropathy. One patient had factor V Leiden mutation and two patients had protein S deficiency. Patients were anticoagulated in the peri‐operative and post‐transplant period. All index transplants were performed with living donor kidneys. There were no adverse outcomes in children with thrombophilias despite having significantly lower weight at the time of transplant vs. children without thrombophilia. The incidence of graft thrombosis in the pediatric renal transplant recipients is high. We identify a potential cause of thrombosis in children not well documented in the literature. A high index of suspicion combined with preoperative screening and diagnosis of thrombophilias and an appropriate treatment plan may decrease the incidence of graft thrombosis in infants and small children undergoing renal transplantation.
Epidemiology of blood donors in Japan, positive for hepatitis B virus and hepatitis C virus by nucleic acid amplification testing
Authors: Murokawa H. , Yoshikawa A. , Ohnuma H. , Iwata A. , Katoh N. , Miyamoto M. , Mine H. , Emura H. , Tadokoro K. ,   the Japanese Red Cross NAT Screening Research Group
Published: January 2005

Background and Objectives  The Japanese Red Cross screens seronegative blood donors by nucleic acid amplification testing (NAT) for hepatitis B, hepatitis C and human immunodeficiency virus‐1 markers. NAT‐positive donors thus identified seemed to have a different infectious background from serologically positive donors. The purpose of our study was to characterize this background in the hepatitis B virus (HBV) and hepatitis C virus (HCV) NAT‐positive donors.

Materials and Methods  Some 328 HBV DNA‐positive and 44 HCV RNA‐positive donors were detected by NAT testing of seronegative blood donors. These were characterized regarding age, gender and genotype of HBV and HCV.

Results Those who were HBV NAT‐positive were mainly young, in particular teenage girls. In Japan, genotypes C and B have previously been dominant, but recently genotype A has increased, and genotype H was recently detected. In HBV NAT‐positive donors, the rate of genotype A was high (12·2%) compared with patients in hospital (1·7–2%). Donors who were HCV NAT‐positive were also young, but mostly men in their twenties. The ratio of genotype 1b to 2a or 1b to 2b in HCV NAT‐positive donors differed from that of hospitalized patients in Japan. We did not find genotype 1a, which is dominant in the USA.

Conclusions  The high‐risk donors detected by NAT were mainly young, with a different distribution of genotypes from that of hospitalized patients, regarding both HBV and HCV. The rare HBV genotype H has been found for the first time in Japan. The findings reflect the present spread of hepatitis viruses B and C.
Inoculated Host Range and Effect of Host on Morphology and Size of Macroconidia Produced by Claviceps africana and Claviceps sorghi
Authors: Muthusubramanian V. , Bandyopadhyay R. , Tooley P. W. , Rajaram Reddy D.
Published: January 2005

Twenty graminaceous plant species were evaluated for their susceptibility to the two sorghum ergot pathogens Claviceps sorghi and Claviceps africana. Five species viz., Sorghum arundinaceum, Sorghum halepense, Sorghum versicolor, Sorghum virgatum and Pennisetum glaucum were found to become infected by both pathogens via inoculation with 106 conidia/ml. Species which did not become infected under these conditions included Pennisetum pedicellatum, Zea mays, and species of Panicum, Brachiaria, Cenchrus, Andropogon, Dichanthium, Chrysopogon, Iseilema, Bothriochloa and Chloris. Honeydew secretions were observed from infected flowers of susceptible plant species. There was marked variation in size of macroconidia of both C. sorghi and C. africana on different hosts on which the pathogens were able to establish symptoms. Dimorphism was observed for macroconidia produced on P. glaucum, as elliptical and spindle shaped macroconidia were observed. Based on inoculation under greenhouse conditions, we conclude that C. sorghi and C. africana may have similar host ranges.
As good as dead? Sublethal predation facilitates lethal predation on an intertidal clam
Authors: Meyer John J. , Byers James E.
Published: January 2005

Although ecologists have speculated that sublethal predation can impact prey dynamics, consequences of these predator effects have seldom been experimentally tested. In soft‐sediment marine communities, fishes crop extended feeding siphons of buried clams, potentially causing clams to reduce their burial depth, thereby enhancing their susceptibility to excavating lethal predators. We simulated cropping of the confamilial clams, Protothaca staminea and Venerupis philippinarum, by removing the top 40% of siphons, which caused each species to burrow 33–50% shallower than conspecifics with intact siphons. To examine subsequent consequences of reduced burial depth, we exposed cropped and intact clams to natural levels of predation in the field. Because of a naturally longer siphon, Protothaca, even after cropping, remained at relatively safe burial depths. In contrast, siphon cropping nearly doubled the mortality rate of Venerupis. Thus, while sublethal predation facilitates lethal predation, this linkage depends on specific life history characteristics, even among ecologically similar species.
A general model of local competition for space
Authors: Crowley Philip H. , Davis Heather M. , Ensminger Amanda L. , Fuselier Linda C. , Kasi Jackson J. , Nicholas McLetchie D.
Published: January 2005

Local competition for space across a wide array of taxa typically involves three mechanisms that we denote here as expansion (spreading into unoccupied habitat), lottery (replacing dead competitors), and overgrowth (encroaching on competitors along zones of contact). By formulating and analysing a simple, general model incorporating these features, we identify ecological conditions and life‐history features that lead to stable coexistence or competitive exclusion (with or without initial‐condition dependence) and gain insight by linking these to case studies in the literature. We demonstrate the importance of contact inhibition, a little‐studied feature of overgrowth, and we show how life‐history tradeoffs may influence and be influenced by local competition for space. The general model we present can help indicate whether local interactions are sufficient to explain patterns of coexistence or exclusion and can serve as the foundation for more specific, realistic models of spatial competition.
Identification of high‐use habitat and threats to leatherback sea turtles in northern waters: new directions for conservation
Authors: James Michael C. , Andrea Ottensmeyer C. , Myers Ransom A.
Published: January 2005

Incidental capture in fisheries threatens many marine vertebrates, however, conservation cannot be effective without identifying major sources of mortality. For the critically endangered leatherback turtle (Dermochelys coriacea), a reliance on fisheries observer data and an absence of behavioural data sets corresponding to a large and diverse sample of animals have focused conservation efforts on a very limited part of the species marine habitat. Using the largest satellite telemetry data set for Atlantic leatherbacks, morphometrics from foraging animals and entanglement records, we show annual return migrations to key feeding areas by males, females and juveniles, and demonstrate the importance of northern latitudes to leatherbacks. We show that leatherbacks are vulnerable to entanglement in northern coastal and shelf waters, where turtle–fishery interactions represent a greater threat to this species than previously recognized. Unless conservation efforts expand to coastal and shelf areas, present efforts alone will not be sufficient to save the species.
Belowground organism activities affect plant aboveground phenotype, inducing plant tolerance to parasites
Authors: Blouin Manuel , Zuily‐Fodil Yasmine , Pham‐Thi Anh‐Thu , Laffray Daniel , Reversat Georges , Pando Anne , Tondoh Jerome , Lavelle Patrick
Published: January 2005

Soil fauna activities are probably more important than currently acknowledged in determining individual plant response to stresses and overall plant diversity. Here we demonstrate that the positive effect of earthworms on rice could be the result of a systemic effect on plant physiology. Moreover, this effect could improve tolerance to stressors such as parasitic nematodes. In a controlled experiment, an 82% decrease in the production of infested plants was suppressed when earthworms were present. Earthworms had no direct effect on nematode population size. In their presence, however, root biomass was not affected by nematodes and the expected inhibition of photosynthesis was suppressed. In the leaves, the expression of three stress‐responsive genes (coding for lipoxygenase, phospholipase D and cysteine protease) was modulated by the presence of belowground invertebrate activities. We document conflicting systemic effects of parasitic nematodes and beneficial earthworms, although we cannot precisely identify the mechanism involved. These results reveal the importance of non‐trophic belowground/aboveground interactions for plant health and response to stresses.
Bridging the Gap: Understanding Reassurance Policing
Authors: Millie Andrew , Herrington Victoria
Published: January 2005

Abstract: While crime rates in England and Wales have been falling, the perception has remained, for many, that crime is rising. It has also been assumed that fear of crime is high, although measures of fear have been declining since the mid‐1990s. Of greater concern is a concurrent decline in confidence in the police. This ‘gap’ underpins the need for reassurance as a means of gaining legitimacy for policing decisions. We consider the background to reassurance policing and examine interpretation at ground level through interviews with officers involved in a strategy trial based upon a ‘signal crimes’ perspective.
Learning from ‘Near Misses’: Interviews with Women who Survived an Incident of Severe Self‐Harm in Prison
Authors: Borrill Jo , Snow Louisa , Medlicott Diana , Teers Rebecca , Paton Jo
Published: January 2005

Abstract: This article describes qualitative research with women survivors of potentially lethal self‐harm in prison. In‐depth interviews were carried out during 2002/03 with 15 women, (adults and young offenders), from six establishments. The interviews focused on the women's own accounts of the ‘near miss’ incident, including intentions and motivations, factors leading up to the incident, experiences of care and support, current self‐harm and suicidality, and suggestions for prevention. Recommendations include: improvements to the general prison regime; training and support for staff; specialist help for women with histories of abuse, mental illness, or borderline personality disorder; improved support following stressful life events.
Stalking in Adolescence: A Case Report
Authors: Vaidya Girish , Chalhoub Nevyne , Newing Jo
Published: January 2005

Stalking has overlaps with criminal justice system and mental health services. Research has, so far, identified stalking to be a predominantly adult male phenomenon. We present the case of a 15‐year‐old girl who was referred for stalking her learning mentor. The relevant literature is discussed and areas for further research are highlighted.
The Effects of Geography and Spatial Behavior on Health Care Utilization among the Residents of a Rural Region
Authors: Arcury Thomas A. , Gesler Wilbert M. , Preisser John S. , Sherman Jill , Spencer John , Perin Jamie
Published: January 2005

Objective.This analysis determines the importance of geography and spatial behavior as predisposing and enabling factors in rural health care utilization, controlling for demographic, social, cultural, and health status factors.

Data Sources.A survey of 1,059 adults in 12 rural Appalachian North Carolina counties.

Study Design.This cross‐sectional study used a three‐stage sampling design stratified by county and ethnicity. Preliminary analysis of health services utilization compared weighted proportions of number of health care visits in the previous 12 months for regular check‐up care, chronic care, and acute care across geographic, sociodemographic, cultural, and health variables. Multivariable logistic models identified independent correlates of health services utilization.

Data Collection Methods.Respondents answered standard survey questions. They located places in which they engaged health related and normal day‐to‐day activities; these data were entered into a geographic information system for analysis.

Principal Findings.Several geographic and spatial behavior factors, including having a driver's license, use of provided rides, and distance for regular care, were significantly related to health care utilization for regular check‐up and chronic care in the bivariate analysis. In the multivariate model, having a driver's license and distance for regular care remained significant, as did several predisposing (age, gender, ethnicity), enabling (household income), and need (physical and mental health measures, number of conditions). Geographic measures, as predisposing and enabling factors, were related to regular check‐up and chronic care, but not to acute care visits.

Conclusions.These results show the importance of geographic and spatial behavior factors in rural health care utilization. They also indicate continuing inequity in rural health care utilization that must be addressed in public policy.
Response Rates and Response Bias for 50 Surveys of Pediatricians
Authors: Cull William L. , O'Connor Karen G. , Sharp Sanford , Tang Suk‐fong S.
Published: January 2005

Research Objective. To track response rates across time for surveys of pediatricians, to explore whether response bias is present for these surveys, and to examine whether response bias increases with lower response rates.

Data Source/Study Setting. A total of 63,473 cases were gathered from 50 different surveys of pediatricians conducted by the American Academy of Pediatrics (AAP) since 1994. Thirty‐one surveys targeted active U.S. members of the AAP, six targeted pediatric residents, and the remaining 13 targeted AAP‐member and nonmember pediatric subspecialists. Information for the full target samples, including nonrespondents, was collected using administrative databases of the AAP and the American Board of Pediatrics.

Study Design. To assess bias for each survey, age, gender, location, and AAP membership type were compared for respondents and the full target sample. Correlational analyses were conducted to examine whether surveys with lower response rates had increasing levels of response bias.

Principal Findings. Response rates to the 50 surveys examined declined significantly across survey years (1994–2002). Response rates ranged from 52 to 81 percent with an average of 68 percent. Comparisons between respondents and the full target samples showed the respondent group to be younger, to have more females, and to have less specialty‐fellow members. Response bias was not apparent for pediatricians' geographical location. The average response bias, however, was fairly small for all factors: age (0.45 years younger), gender (1.4 percentage points more females), and membership type (1.1 percentage points fewer specialty‐fellow members). Gender response bias was found to be inversely associated with survey response rates (r=−0.38). Even for the surveys with the lowest response rates, amount of response bias never exceeded 5 percentage points for gender, 3 years for age, or 3 percent for membership type.

Conclusions. While response biases favoring women, young physicians, and nonspecialty‐fellow members were found across the 52–81 percent response rates examined in this study, the amount of bias was minimal for these factors that could be tested. At least for surveys of pediatricians, more attention should be devoted by investigators to assessments of response bias rather than relying on response rates as a proxy of response bias.
Resolving Controversies Regarding Hemodiafiltration versus Hemodialysis: The Dutch Convective Transport Study
Authors: Penne E. Lars , Blankestijn Peter J. , Bots Michiel L. , Van Den Dorpel Marinus A. , Grooteman Muriel P. C. , Nubé Menso J. , Ter Wee Piet M. ,   on behalf of the CONTRAST Group
Published: January 2005

Hemodialysis patients suffer from a high incidence of cardiovascular disease. Among the many predisposing factors, such as high blood pressure, dyslipidemia, and fluid overload, the accumulation of high molecular weight uremic toxins, the so‐called middle molecules, may play an important role. Since convective therapies such as online hemodiafiltration have a better clearance profile for these compounds than standard hemodialysis, it has been suggested that these dialysis strategies may reduce cardiovascular morbidity and mortality. As reliable data on these issues are not available, the Dutch Convective Transport Study (CONTRAST) was recently initiated. This prospective randomized trial was designed to compare online hemodiafiltration with low‐flux hemodialysis with respect to cardiovascular morbidity and mortality.
Cultural identities and cultural congruency: a new model for evaluating mental distress in immigrants
Authors: Bhugra D.
Published: January 2005

Objective:  Societies and cultures have been described as being individualistic or collectivist (also called ego‐centric or socio‐centric). Similarly individuals are idiocentric or allocentric.

Method:  Using migration, migrants, ethnic minorities, collectivism and individualism, four databases of Embase, Medline, PsychInfo and Social Sciences abstracts were searched. Other key words included mental disorder, mental distress, psychiatric and psychological disorders. In addition, hand searches were conducted from the relevant books, monographs and secondary references.

Results:  Migration, cultural identity and mental distress are linked. In addition, social support can provide a buffer against mental illness. Other vulnerability factors in migrants include the type of society they originate from and the type of society they settle in.

Conclusion:  When individuals migrate from one type of culture to another it is likely that depending upon their own personality traits (along with their biopsycho‐social vulnerabilities) may develop psychiatric disorders. The cognitions and idioms of distress will be influenced by cultural factors. The clinicians must take into account cultural background when planning any interventions to enable a stronger therapeutic alliance.
R120G αB‐crystallin promotes the unfolding of reduced α‐lactalbumin and is inherently unstable
Authors: Treweek Teresa M. , Rekas Agata , Lindner Robyn A. , Walker Mark J. , Aquilina J. Andrew , Robinson Carol V. , Horwitz Joseph , Der Perng Ming , Quinlan Roy A. , Carver John A.
Published: January 2005

α‐Crystallin is the principal lens protein which, in addition to its structural role, also acts as a molecular chaperone, to prevent aggregation and precipitation of other lens proteins. One of its two subunits, αB‐crystallin, is also expressed in many nonlenticular tissues, and a natural missense mutation, R120G, has been associated with cataract and desmin‐related myopathy, a disorder of skeletal muscles [Vicart P, Caron A, Guicheney P, Li Z, Prevost MC, Faure A, Chateau D, Chapon F, Tome F, Dupret JM, Paulin D & Fardeau M (1998) Nat Genet20, 92–95]. In the present study, real‐time 1H‐NMR spectroscopy showed that the ability of R120G αB‐crystallin to stabilize the partially folded, molten globule state of α‐lactalbumin was significantly reduced in comparison with wild‐type αB‐crystallin. The mutant showed enhanced interaction with, and promoted unfolding of, reduced α‐lactalbumin, but showed limited chaperone activity for other target proteins. Using NMR spectroscopy, gel electrophoresis, and MS, we observed that, unlike the wild‐type protein, R120G αB‐crystallin is intrinsically unstable in solution, with unfolding of the protein over time leading to aggregation and progressive truncation from the C‐terminus. Light scattering, MS, and size‐exclusion chromatography data indicated that R120G αB‐crystallin exists as a larger oligomer than wild‐type αB‐crystallin, and its size increases with time. It is likely that removal of the positive charge from R120 of αB‐crystallin causes partial unfolding, increased exposure of hydrophobic regions, and enhances its susceptibility to proteolysis, thus reducing its solubility and promoting its aggregation and complexation with other proteins. These characteristics may explain the involvement of R120G αB‐crystallin with human disease states.
EspB from enterohaemorrhagic Escherichia coli is a natively partially folded protein
Authors: Hamada Daizo , Kato Tomoaki , Ikegami Takahisa , Suzuki Kayo N. , Hayashi Makoto , Murooka Yoshikatsu , Honda Takeshi , Yanagihara Itaru
Published: January 2005

The structural properties of EspB, a virulence factor of the Escherichia coli O157 type III secretion system, were characterized. Far‐UV and near‐UV CD spectra, recorded between pH 1.0 and pH 7.0, show that the protein assumes α‐helical structures and that some tyrosine tertiary contacts may exist. All tyrosine side‐chains are exposed to water, as determined by acrylamide fluorescence quenching spectroscopy. An increase in the fluorescence intensity of 8‐anilinonaphthalene‐1‐sulfonate was observed at pH 2.0 in the presence of EspB, whereas no such increase in fluorescence was observed at pH 7.0. These data suggest the formation of a molten globule state at pH 2.0. Destabilization of EspB at low pH was shown by urea‐unfolding transitions, monitored by far‐UV CD spectroscopy. The result from a sedimentation equilibrium study indicated that EspB assumes a monomeric form at pH 7.0, although its Stokes radius (estimated by multiangle laser light scattering) was twice as large as expected for a monomeric globular structure of EspB. These data suggest that EspB, at pH 7.0, assumes a relatively expanded conformation. The chemical shift patterns of EspB 15N‐1H heteronuclear single quantum correlation spectra at pH 2.0 and 7.0 are qualitatively similar to that of urea‐unfolded EspB. Taken together, the properties of EspB reported here provide evidence that EspB is a natively partially folded protein, but with less exposed hydrophobic surface than traditional molten globules. This structural feature of EspB may be advantageous when EspB interacts with various biomolecules during the bacterial infection of host cells.
Identification of a 250 kDa putative microtubule‐associated protein as bovine ferritin
Authors: Hasan Mohammad R. , Morishima Daisuke , Tomita Kyoko , Katsuki Miho , Kotani Susumu
Published: January 2005

We reported previously on the purification and partial characterization of a putative microtubule‐associated protein (MAP) from bovine adrenal cortex with an approximate molecular mass of 250 kDa. The protein was expressed ubiquitously in mammalian tissues, and bound to microtubules in vitro and in vivo, but failed to promote tubulin polymerization into microtubules. In the present study, partial amino acid sequencing revealed that the protein shares an identical primary structure with the widely distributed iron storage protein, ferritin. We also found that the putative MAP and ferritin are indistinguishable from each other by electrophoretic mobility, immunological properties and morphological appearance. Moreover, the putative MAP conserves the iron storage and incorporation properties of ferritin, confirming that the two are structurally and functionally the same protein. This fact led us to investigate the interaction of ferritin with microtubules by direct electron microscopic observations. Ferritin was bound to microtubules either singly or in the form of large intermolecular aggregates. We suggest that the formation of intermolecular aggregates contributes to the intracellular stability of ferritin. The interactions between ferritin and microtubules observed in this study, in conjunction with the previous report that the administration of microtubule depolymerizing drugs increases the serum release of ferritin in rats [Ramm GA, Powell LW & Halliday JW (1996) J Gastroenterol Hepatol11, 1072–1078], support the probable role of microtubules in regulating the intracellular concentration and release of ferritin under different physiological circumstances.
Crystal structure of a subtilisin‐like serine proteinase from a psychrotrophic Vibrio species reveals structural aspects of cold adaptation
Authors: Arnórsdóttir Jóhanna , Kristjánsson Magnús M. , Ficner Ralf
Published: January 2005

The crystal structure of a subtilisin‐like serine proteinase from the psychrotrophic marine bacterium, Vibrio sp. PA‐44, was solved by means of molecular replacement and refined at 1.84 Å. This is the first structure of a cold‐adapted subtilase to be determined and its elucidation facilitates examination of the molecular principles underlying temperature adaptation in enzymes. The cold‐adapted Vibrio proteinase was compared with known three‐dimensional structures of homologous enzymes of meso‐ and thermophilic origin, proteinase K and thermitase, to which it has high structural resemblance. The main structural features emerging as plausible determinants of temperature adaptation in the enzymes compared involve the character of their exposed and buried surfaces, which may be related to temperature‐dependent variation in the physical properties of water. Thus, the hydrophobic effect is found to play a significant role in the structural stability of the meso‐ and thermophile enzymes, whereas the cold‐adapted enzyme has more of its apolar surface exposed. In addition, the cold‐adapted Vibrio proteinase is distinguished from the more stable enzymes by its strong anionic character arising from the high occurrence of uncompensated negatively charged residues at its surface. Interestingly, both the cold‐adapted and thermophile proteinases differ from the mesophile enzyme in having more extensive hydrogen‐ and ion pair interactions in their structures; this supports suggestions of a dual role of electrostatic interactions in the adaptation of enzymes to both high and low temperatures. The Vibrio proteinase has three calcium ions associated with its structure, one of which is in a calcium‐binding site not described in other subtilases.
G protein βγ subunits mediate presynaptic inhibition of transmitter release from rat superior cervical ganglion neurones in culture
Authors: Stephens Gary J. , Mochida Sumiko
Published: January 2005

The activation of presynaptic G protein‐coupled receptors (GPCRs) is widely reported to inhibit transmitter release; however, the lack of accessibility of many presynaptic terminals has limited direct analysis of signalling mediators. We studied GPCR‐mediated inhibition of fast cholinergic transmission between superior cervical ganglion neurones (SCGNs) in culture. The adrenoceptor agonist noradrenaline (NA) caused a dose‐related reduction in evoked excitatory postsynaptic potentials (EPSPs). NA‐induced EPSP decrease was accompanied by effects on the presynaptic action potential (AP), reducing AP duration and amplitude of the after‐hyperpolarization (AHP), without affecting the pre‐ and postsynaptic membrane potential. All effects of NA were blocked by yohimbine and synaptic transmission was reduced by clonidine, consistent with an action at presynaptic α2‐adrenoceptors. NA‐induced inhibition of transmission was sensitive to pre‐incubation of SCGNs with pertussis toxin (PTX), implicating the involvement of Gαi/oβγ subunits. Expression of Gα transducin, an agent which sequesters G protein βγ (Gβγ) subunits, in the presynaptic neurone caused a time‐dependent attenuation of NA‐induced inhibition. Injection of purified Gβγ subunits into the presynaptic neurone inhibited transmission, and also reduced the AHP amplitude. Furthermore, NA‐induced inhibition was occluded by pre‐injection of Gβγ subunits. The Ca2+ channel blocker Cd2+ mimicked NA effects on transmitter release. Cd2+, NA and Gβγ subunits also inhibited somatic Ca2+ current. In contrast to effects on AP‐evoked transmitter release, NA had no clear action on AP‐independent EPSPs induced by hypertonic solutions. These results demonstrate that Gβγ subunits functionally mediate inhibition of transmitter release by α2‐adrenoceptors and represent important regulators of synaptic transmission at mammalian presynaptic terminals.
Time‐matched pre‐ and postsynaptic changes of GABAergic synaptic transmission in the developing mouse superior colliculus
Authors: Kirischuk Sergei , Jüttner René , Grantyn Rosemarie
Published: January 2005

Developmental changes in the kinetics of GABAergic postsynaptic currents have been reported for various brain structures. However, it has remained unclear whether these modifications are matched by presynaptic changes. We addressed this question by analysing evoked IPSCs (eIPSCs) in mouse superior colliculus slices between postnatal day (P) 1 and 22. eIPSCs were elicited by electrical stimulation and measured in the whole‐cell patch‐clamp configuration. IPSCs were analysed using the binomial model of synaptic transmission. The readily releasable pool (RRP, N) was estimated from the cumulative eIPSC amplitude histograms during 50‐Hz stimulation. Median delayed IPSC (dIPSC) amplitude was used as a quantal amplitude (q) estimate. The mean release probability (p) was determined as the mean eIPSC amplitude divided by the product of RRP and q. The experiments revealed that GABAergic synapses pass through two distinct periods of functional adjustment: (i) P1–3 (coincidental with the onset of glutamatergic spontaneous activity and a switch from depolarizing to hyperpolarizing GABA action) displayed a significant decrease of p, associated with an increase in the paired‐pulse ratio (eIPSC2/eIPSC1); and (ii) P6–15 (the period before and shortly after eye opening) is characterized by a drastic reduction of IPSC duration. On the presynaptic side, it was accompanied by a down‐regulation of asynchronous release in favour of stimulus‐locked synchronous release. We conclude that postsynaptic modifications of GABAergic synaptic transmission in the superior colliculus (SC) are indeed accompanied by presynaptic changes, and this may guarantee the necessary efficacy of inhibition during the developmental reconstruction of the synaptic network in the SC.