127 research outputs found

    Fluctuating Environments, Sexual Selection and the Evolution of Flexible Mate Choice in Birds

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    Environmentally-induced fluctuation in the form and strength of natural selection can drive the evolution of morphology, physiology, and behavior. Here we test the idea that fluctuating climatic conditions may also influence the process of sexual selection by inducing unexpected reversals in the relative quality or sexual attractiveness of potential breeding partners. Although this phenomenon, known as ‘ecological cross-over’, has been documented in a variety of species, it remains unclear the extent to which it has driven the evolution of major interspecific differences in reproductive behavior. We show that after controlling for potentially influential life history and demographic variables, there are significant positive associations between the variability and predictability of annual climatic cycles and the prevalence of infidelity and divorce within populations of a taxonomically diverse array of socially monogamous birds. Our results are consistent with the hypothesis that environmental factors have shaped the evolution of reproductive flexibility and suggest that in the absence of severe time constraints, secondary mate choice behaviors can help prevent, correct, or minimize the negative consequences of ecological cross-overs. Our findings also illustrate how a basic evolutionary process like sexual selection is susceptible to the increasing variability and unpredictability of climatic conditions that is resulting from climate change

    The RhoA GEF Syx Is a Target of Rnd3 and Regulated via a Raf1-Like Ubiquitin-Related Domain

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    Background: Rnd3 (RhoE) protein belongs to the unique branch of Rho family GTPases that has low intrinsic GTPase activity and consequently remains constitutively active [1,2]. The current consensus is that Rnd1 and Rnd3 function as important antagonists of RhoA signaling primarily by activating the ubiquitous p190 RhoGAP [3], but not by inhibiting the ROCK family kinases. Methodology/Principal Findings: Rnd3 is abundant in mouse embryonic stem (mES) cells and in an unbiased two-step affinity purification screen we identified a new Rnd3 target, termed synectin-binding RhoA exchange factor (Syx), by mass spectrometry. The Syx interaction with Rnd3 does not occur through the Syx DH domain but utilizes a region similar to the classic Raf1 Ras-binding domain (RBD), and most closely related to those in RGS12 and RGS14. We show that Syx behaves as a genuine effector of Rnd3 (and perhaps Rnd1), with binding characteristics similar to p190-RhoGAP. Morpholinooligonucleotide knockdown of Syx in zebrafish at the one cell stage resulted in embryos with shortened anterior-posterior body axis: this phenotype was effectively rescued by introducing mouse Syx1b mRNA. A Rnd3-binding defective mutant of Syx1b mutated in the RBD (E164A/R165D) was more potent in rescuing the embryonic defects than wild-type Syx1b, showing that Rnd3 negatively regulates Syx activity in vivo. Conclusions/Significance: This study uncovers a well defined Rnd3 effector Syx which is widely expressed and directl

    The development of a multidisciplinary fall risk evaluation tool for demented nursing home patients in the Netherlands

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    BACKGROUND: Demented nursing home patients are at high risk for falls. Falls and associated injuries can have a considerable influence on the autonomy and quality of life of patients. The prevention of falls among demented patients is therefore an important issue. In order to intervene in an efficient way in this group of patients, it is important to systematically evaluate the fall risk profile of each individual patient so that for each patient tailor-made preventive measures can be taken. Therefore, the objective of the present study is to develop a feasible and evidence based multidisciplinary fall risk evaluation tool to be used for tailoring preventive interventions to the needs of individual demented patients. METHODS: To develop this multidisciplinary fall risk evaluation tool we have chosen to combine scientific evidence on the one hand and experts' opinions on the other hand. Firstly, relevant risk factors for falling in elderly persons were gathered from the literature. Secondly, a group of Dutch experts in the field of falls and fall prevention in the elderly were consulted to judge the suitability of these risk factors for use in a multidisciplinary fall risk evaluation tool for demented nursing home patients. Thirdly, in order to generate a compact list of the most relevant risk factors for falling in demented elderly, all risk factors had to fulfill a set of criteria indicating their relevance for this specific target population. Lastly the final list of risk factors resulting from the above mentioned procedure was presented to the expert group. The members were also asked to give their opinion about the practical use of the tool. RESULTS: The multidisciplinary fall risk evaluation tool we developed includes the following items: previous falls, use of medication, locomotor functions, and (correct) choice and use of assistive and protective devices. The tool is developed for the multidisciplinary teams of the nursing homes. CONCLUSION: This evidence and practice based multidisciplinary fall risk evaluation tool targets the preventive interventions aimed to prevent falls and their negative consequences in demented nursing home patients

    Validity of the Falls Risk for Older People in the Community (FROP‑Com) tool to predict falls and fall injuries for older people presenting to the emergency department after falling

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    The aims of this study were to (1) externally validate the accuracy of the Falls Risk for Older People in the Community (FROP-Com) falls risk assessment tool in predicting falls and (2) undertake initial validation of the accuracy of the FROPCom to predict injurious falls (requiring medical attention) in people aged ≥ 60 years presenting to emergency departments (EDs) after falling. Two hundred and thirteen participants (mean age = 72.4 years; 59.2% women) were recruited (control group of a randomised controlled trial). A FROP-Com assessment was completed at a home visit within 2 weeks of ED discharge. Data on falls and injurious falls requiring medical attention were collected via monthly falls calendars for the next 12 months. Predictive accuracy was evaluated using sensitivity and specificity of a high-risk FROP-Com classification (score ≥ 19) in predicting a fall and injurious falls requiring medical attention. Fifty per cent of participants fell, with 60.4% of falls requiring medical attention. Thirty-two per cent were classified as high, 49% as moderate and 19% low falls risk. Low sensitivity was achieved for the FROP-Com high-risk classification for predicting falls (43.4%) and injurious falls (34.4%), although specificity was high (79.4% and 78.6%, respectively). Despite the FROP-Com’s low predictive accuracy, the high fall rate and high falls risk of the sample suggest that older people who fall, present to ED and are discharged home are at high risk of future falls. In high-falls-risk populations such as in this study, the FROP-Com is not a valid tool for classifying risk of falls or injurious falls. Its potential value may instead be in identifying risk factors for falling to direct tailoring of falls prevention interventions to reduce future falls

    Urinary C-Peptide Measurement as a Marker of Nutritional Status in Macaques

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    Studies of the nutritional status of wild animals are important in a wide range of research areas such as ecology, behavioural ecology and reproductive biology. However, they have so far been strongly limited by the indirect nature of the available non-invasive tools for the measurement of individual energetic status. The measurement of urinary C-peptide (UCP), which in humans and great apes shows a close link to individual nutritional status, may be a more direct, non-invasive tool for such studies in other primates as well and possibly even in non-primate mammals. Here, we test the suitability of UCPs as markers of nutritional status in non-hominid primates, investigating relationships between UCPs and body-mass-index (BMI), skinfold fatness, and plasma C-peptide levels in captive and free-ranging macaques. We also conducted a food reduction experiment, with daily monitoring of body weight and UCP levels. UCP levels showed significant positive correlations with BMI and skinfold fatness in both captive and free-ranging animals and with plasma C-peptide levels in captive ones. In the feeding experiment, UCP levels were positively correlated with changes in body mass and were significantly lower during food reduction than during re-feeding and the pre-experimental control condition. We conclude that UCPs may be used as reliable biomarkers of body condition and nutritional status in studies of free-ranging catarrhines. Our results open exciting opportunities for energetic studies on free-ranging primates and possibly also other mammals

    MR imaging of osteochondral grafts and autologous chondrocyte implantation

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    Surgical articular cartilage repair therapies for cartilage defects such as osteochondral autograft transfer, autologous chondrocyte implantation (ACI) or matrix associated autologous chondrocyte transplantation (MACT) are becoming more common. MRI has become the method of choice for non-invasive follow-up of patients after cartilage repair surgery. It should be performed with cartilage sensitive sequences, including fat-suppressed proton density-weighted T2 fast spin-echo (PD/T2-FSE) and three-dimensional gradient-echo (3D GRE) sequences, which provide good signal-to-noise and contrast-to-noise ratios. A thorough magnetic resonance (MR)-based assessment of cartilage repair tissue includes evaluations of defect filling, the surface and structure of repair tissue, the signal intensity of repair tissue and the subchondral bone status. Furthermore, in osteochondral autografts surface congruity, osseous incorporation and the donor site should be assessed. High spatial resolution is mandatory and can be achieved either by using a surface coil with a 1.5-T scanner or with a knee coil at 3 T; it is particularly important for assessing graft morphology and integration. Moreover, MR imaging facilitates assessment of complications including periosteal hypertrophy, delamination, adhesions, surface incongruence and reactive changes such as effusions and synovitis. Ongoing developments include isotropic 3D sequences, for improved morphological analysis, and in vivo biochemical imaging such as dGEMRIC, T2 mapping and diffusion-weighted imaging, which make functional analysis of cartilage possible

    Propagation of RML Prions in Mice Expressing PrP Devoid of GPI Anchor Leads to Formation of a Novel, Stable Prion Strain

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    PrPC, a host protein which in prion-infected animals is converted to PrPSc, is linked to the cell membrane by a GPI anchor. Mice expressing PrPC without GPI anchor (tgGPI- mice), are susceptible to prion infection but accumulate anchorless PrPSc extra-, rather than intracellularly. We investigated whether tgGPI− mice could faithfully propagate prion strains despite the deviant structure and location of anchorless PrPSc. We found that RML and ME7, but not 22L prions propagated in tgGPI− brain developed novel cell tropisms, as determined by the Cell Panel Assay (CPA). Surprisingly, the levels of proteinase K-resistant PrPSc (PrPres) in RML- or ME7-infected tgGPI− brain were 25–50 times higher than in wild-type brain. When returned to wild-type brain, ME7 prions recovered their original properties, however RML prions had given rise to a novel prion strain, designated SFL, which remained unchanged even after three passages in wild-type mice. Because both RML PrPSc and SFL PrPSc are stably propagated in wild-type mice we propose that the two conformations are separated by a high activation energy barrier which is abrogated in tgGPI− mice

    Quedas intra-hospitalares na Santa Casa de Belo Horizonte MG são adequadamente relatadas?

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    O envelhecimento populacional é uma realidade que chega imbuída de complicações as quais muitas vezes tornam-se problema de saúde pública, como é o caso das quedas hospitalares. Estas acarretam uma série de conseqüências negativas ao paciente e sua família, bem como ao sistema de saúde. O objetivo deste estudo foi avaliar e quantificar, por meio de entrevistas com os profissionais responsáveis pelos cuidados dos pacientes da Santa Casa de Belo Horizonte, a ocorrência de quedas durante a hospitalização. Foram entrevistados 37 profissionais (médicos, residentes, enfermeiros e prestadores de serviços) através de questionário semi-estruturado com 11 questões referentes ao histórico de quedas no setor, englobando informações sobre número de episódios, local, horário, idade do paciente, atividade que realizava no momento, conseqüências, bem como questões referentes à adaptação ambiental. A análise dos dados feita por meio de estatísticas descritivas. Os resultados mostraram que 65% dos funcionários relataram a ocorrência de quedas. A maioria dos caidores (73%) eram homens, com média de idade de 78,62 anos (DP +- 7,63) e caíram mais nos períodos da manhã (31%) e noite (31%), principalmente no quarto (48%) e no banheiro (42%) sendo que 50% dos episódios não foram injuriosos. Conclui-se que os episódios de quedas ocorrem no ambiente hospitalar, mas não são reportados de maneira adequada, tornando necessário adoção de medidas educativas aos profissionais que lidam com esta população.The Population ageing is a reality that comes gripped by complications related to aging, being in-hospital falls one of the most important, considering that they bring on a lot of negative consequences to the patient and his family as well as to the health system. The objective of this study was to assess and quantify, through the analyses of interviews with professionals responsible for the care of the patients at Santa Casa of Belo Horizonte, the occurrence of in-hospital falls. The interview was accomplished with 37 professionals(doctors, interns and nurses) through a semi-structured questionnaire which comprehended 11 questions related to the historical of falls in the sector, comprising information on the number of episodes, setting, time, patient age, activity performed at the moment, consequences, as well as questions regarding to environment adaptation. Data analysis conducted by means of descriptive statistics of the interviews showed that 65% of the employee reported the occurrence of falls. The majority (73%) of fallers was men, with mean age of 78, 62 years (SD +- 7, 63) and fell more in the morning (31%) and in the evening (31%), mainly in the room (48%) and in the bathroom (42%), being 50% of the episodes non-injurious. We conclude that falls episodes occur in the hospital setting, but are not reported adequately, showing the need of adoption of educational measures to the professional who deal with this population

    Relative Burden of Large CNVs on a Range of Neurodevelopmental Phenotypes

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    While numerous studies have implicated copy number variants (CNVs) in a range of neurological phenotypes, the impact relative to disease severity has been difficult to ascertain due to small sample sizes, lack of phenotypic details, and heterogeneity in platforms used for discovery. Using a customized microarray enriched for genomic hotspots, we assayed for large CNVs among 1,227 individuals with various neurological deficits including dyslexia (376), sporadic autism (350), and intellectual disability (ID) (501), as well as 337 controls. We show that the frequency of large CNVs (>1 Mbp) is significantly greater for ID–associated phenotypes compared to autism (p = 9.58×10−11, odds ratio = 4.59), dyslexia (p = 3.81×10−18, odds ratio = 14.45), or controls (p = 2.75×10−17, odds ratio = 13.71). There is a striking difference in the frequency of rare CNVs (>50 kbp) in autism (10%, p = 2.4×10−6, odds ratio = 6) or ID (16%, p = 3.55×10−12, odds ratio = 10) compared to dyslexia (2%) with essentially no difference in large CNV burden among dyslexia patients compared to controls. Rare CNVs were more likely to arise de novo (64%) in ID when compared to autism (40%) or dyslexia (0%). We observed a significantly increased large CNV burden in individuals with ID and multiple congenital anomalies (MCA) compared to ID alone (p = 0.001, odds ratio = 2.54). Our data suggest that large CNV burden positively correlates with the severity of childhood disability: ID with MCA being most severely affected and dyslexics being indistinguishable from controls. When autism without ID was considered separately, the increase in CNV burden was modest compared to controls (p = 0.07, odds ratio = 2.33)

    Support and Assessment for Fall Emergency Referrals (SAFER 1): Cluster Randomised Trial of Computerised Clinical Decision Support for Paramedics

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    Objective: To evaluate effectiveness, safety and cost-effectiveness of Computerised Clinical Decision Support (CCDS) for paramedics attending older people who fall. Design: Cluster trial randomised by paramedic; modelling. Setting: 13 ambulance stations in two UK emergency ambulance services. Participants: 42 of 409 eligible paramedics, who attended 779 older patients for a reported fall. Interventions: Intervention paramedics received CCDS on Tablet computers to guide patient care. Control paramedics provided care as usual. One service had already installed electronic data capture. Main Outcome Measures: Effectiveness: patients referred to falls service, patient reported quality of life and satisfaction, processes of care. Safety: Further emergency contacts or death within one month. Cost-Effectiveness Costs and quality of life. We used findings from published Community Falls Prevention Trial to model cost-effectiveness. Results: 17 intervention paramedics used CCDS for 54 (12.4%) of 436 participants. They referred 42 (9.6%) to falls services, compared with 17 (5.0%) of 343 participants seen by 19 control paramedics [Odds ratio (OR) 2.04, 95% CI 1.12 to 3.72]. No adverse events were related to the intervention. Non-significant differences between groups included: subsequent emergency contacts (34.6% versus 29.1%; OR 1.27, 95% CI 0.93 to 1.72); quality of life (mean SF12 differences: MCS −0.74, 95% CI −2.83 to +1.28; PCS −0.13, 95% CI −1.65 to +1.39) and non-conveyance (42.0% versus 36.7%; OR 1.13, 95% CI 0.84 to 1.52). However ambulance job cycle time was 8.9 minutes longer for intervention patients (95% CI 2.3 to 15.3). Average net cost of implementing CCDS was £208 per patient with existing electronic data capture, and £308 without. Modelling estimated cost per quality-adjusted life-year at £15,000 with existing electronic data capture; and £22,200 without. Conclusions: Intervention paramedics referred twice as many participants to falls services with no difference in safety. CCDS is potentially cost-effective, especially with existing electronic data capture
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