232 research outputs found

    Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers

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    The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia and North America, yet the origins and early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate the phylogenetic affinities of a fossil skull from the Late Miocene of China. This specimen was originally considered Sinocastor, and later transferred to Castor. The aim of this study was to determine whether this form is an early member of Castor, or if it represents a lineage outside of Castor. The specimen was compared to 38 specimens of modern Castor (both C. canadensis and C. fiber) as well as fossil specimens of C. fiber (Pleistocene), C. californicus (Pliocene) and the early castorids Steneofiber eseri (early Miocene). The results show that the specimen falls outside the Castor morphospace and that compared to Castor, Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) shortened incisive foramen, 4) more posteriorly located palatine foramen, 5) longer rostrum, and 6) longer braincase. Also the specimen shows a much shallower basiocciptal depression than what is seen in living Castor, as well as prominently rooted molars. We conclude that Sinocastor is a valid genus. Given the prevalence of apparently primitive traits, Sinocastor might be a near relative of the lineage that gave rise to Castor, implying a possible Asiatic origin for Castor

    Population Based Study of 12 Autoimmune Diseases in Sardinia, Italy: Prevalence and Comorbidity

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    BACKGROUND: The limited availability of prevalence data based on a representative sample of the general population, and the limited number of diseases considered in studies about co-morbidity are the critical factors in study of autoimmune diseases. This paper describes the prevalence of 12 autoimmune diseases in a representative sample of the general population in the South of Sardinia, Italy, and tests the hypothesis of an overall association among these diseases. METHODS: Data were obtained from 21 GPs. The sample included 25,885 people. Prevalence data were expressed with 95% Poisson C.I. The hypothesis of an overall association between autoimmune diseases was tested by evaluating the co-occurrence within individuals. RESULTS: Prevalence per 100,000 are: 552 rheumatoid arthritis, 124 ulcerative colitis, 15 Crohn's disease, 464 type 1 diabetes, 81 systemic lupus erythematosus, 124 celiac disease, 35 myasthenia gravis, 939 psoriasis/psoriatic arthritis, 35 systemic sclerosis, 224 multiple sclerosis, 31 Sjogren's syndrome, and 2,619 autoimmune thyroiditis. An overall association between autoimmune disorders was highlighted. CONCLUSIONS: The comparisons with prevalence reported in current literature do not show outlier values, except possibly for a few diseases like celiac disease and myasthenia gravis. People already affected by a first autoimmune disease have a higher probability of being affected by a second autoimmune disorder. In the present study, the sample size, together with the low overall prevalence of autoimmune diseases in the population, did not allow us to examine which diseases are most frequently associated with other autoimmune diseases. However, this paper makes available an adequate control population for future clinical studies aimed at exploring the co-morbidity of specific pairs of autoimmune disease

    Protective Efficacy of BCG Overexpressing an L,D-Transpeptidase against M. tuberculosis Infection

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    Background: M. bovis Bacille Calmette-Guérin (BCG), currently the only available vaccine against tuberculosis (TB), fails to adequately protect individuals from active and latent TB infection. New vaccines are desperately needed to decrease the worldwide burden of TB. Methods and Findings: We created a recombinant strain of BCG that overproduces an L,D-transpeptidase in order to alter the bacterial peptidoglycan layer and consequently increase the ability of this immunogen to protect against virulent M. tuberculosis (Mtb). We demonstrate that this novel recombinant BCG protects mice against virulent Mtb at least as well as control BCG, as measured by its ability to reduce bacterial burden in lungs and spleen, reduce lung histopathology, and prolong survival. A nutrient starved recombinant BCG preparation, while offering comparable protection, elicited a response characterized by elevated levels of select Th1 cytokines. Conclusions: Recombinant BCG overexpressing a L,D-transpeptidase that is nutrient starved elicits a stronger Th1 type response and is at least as protective as parent BCG. Results from this study suggest that nutrient starvation treatment of live BCG vaccines should be further investigated as a way to increase host induction of Th-1 related cytokines in the development of experimental anti-TB vaccines

    Bayesian Approach to Model CD137 Signaling in Human M.tuberculosis in vitro Responses

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    Abstract Immune responses are qualitatively and quantitatively influenced by a complex network of receptor-ligand interactions. Among them, the CD137:CD137L pathway is known to modulate innate and adaptive human responses against Mycobacterium tuberculosis. However, the underlying mechanisms of this regulation remain unclear. In this work, we developed a Bayesian Computational Model (BCM) of in vitro CD137 signaling, devised to fit previously gathered experimental data. The BCM is fed with the data and the prior distribution of the model parameters and it returns theirposterior distribution and the model evidence, which allows comparing alternative signaling mechanisms. The BCM uses a coupled system of non-linear differential equations to describe the dynamics of Antigen Presenting Cells, Natural Killer and T Cells together with the interpheron (IFN)-c and tumor necrosis factor (TNF)-a levels in the media culture. Fast and complete mixing of the media is assumed. The prior distribution of the parameters that describe the dynamics of the immunological response was obtained from the literature and theoretical considerations Our BCM applies successively the Levenberg-Marquardt algorithm to find the maximum a posteriori likelihood (MAP); the Metropolis Markov Chain Monte Carlo method to approximate the posterior distribution of the parameters and Thermodynamic Integration to calculate the evidence of alternative hypothesis. Bayes factors provided decisive evidence favoring direct CD137 signaling on T cells. Moreover, the posterior distribution of the parameters that describe the CD137 signaling showed that the regulation of IFNc levels is based more on T cells survival than on direct induction. Furthermore, the mechanisms that account for the effect of CD137 signaling on TNF-a production were based on a decrease of TNF-a production by APC and, perhaps, on the increase in APC apoptosis. BCM proved to be a useful tool to gain insight on the mechanisms of CD137 signaling during human response against Mycobacterium tuberculosis.Fil: Darío A Fernández Do Porto. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. INST QUIM FISICA D/L/MATERIALES MED AMB Y ENERG.Fil: Jerónimo Auzmendi. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. INST QUIM FISICA D/L/MATERIALES MED AMB Y ENERG.Fil: Delfina Peña. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. CONSEJO NAC.DE INVEST.CIENTIF.Y TECNICAS. OFICINA DE COORDINACION ADMINISTRATIVA CIUDAD UNIVERSITARIA. INSTITUTO DE QUIMICA BIOLOGICA DE LA FACULTAD DE CS. EXACTAS Y NATURALES. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. DTO.DE QUIMICA BIOLOGICA.Fil: Veronica E Garcia. CONSEJO NAC.DE INVEST.CIENTIF.Y TECNICAS. OFICINA DE COORDINACION ADMINISTRATIVA CIUDAD UNIVERSITARIA. INSTITUTO DE QUIMICA BIOLOGICA DE LA FACULTAD DE CS. EXACTAS Y NATURALES.Fil: Luciano Moffatt. UNIV.DE BUENOS AIRES. FAC.DE CS.EXACTAS Y NATURALES. INST QUIM FISICA D/L/MATERIALES MED AMB Y ENERG

    Backward walking training improves balance in school-aged boys

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    <p>Abstract</p> <p>Background</p> <p>Falls remain a major cause of childhood morbidity and mortality. It is suggested that backward walking (BW) may offer some benefits especially in balance and motor control ability beyond those experienced through forward walking (FW), and may be a potential intervention for prevention of falls. The objective of this study was to investigate the effects of BW on balance in boys.</p> <p>Methods</p> <p>Sixteen healthy boys (age: 7.19 ± 0.40 y) were randomly assigned to either an experimental or a control group. The experimental group participated in a BW training program (12-week, 2 times weekly, and 25-min each time) but not the control group. Both groups had five dynamic balance assessments with a Biodex Stability System (anterior/posterior, medial/lateral, and overall balance index) before, during and after the training (week- 0, 4, 8, 12, 24). Six control and six experimental boys participated in a study comparing kinematics of lower limbs between FW and BW after the training (week-12).</p> <p>Results</p> <p>The balance of experimental group was better than that of control group after 8 weeks of training (<it>P </it>< 0.01), and was still better than that of control group (<it>P </it>< 0.05), when the BW training program had finished for 12 weeks. The kinematic analysis indicated that there was no difference between control and experimental groups in the kinematics of both FW and BW gaits after the BW training (<it>P </it>> 0.05). Compared to FW, the duration of stance phase of BW tended to be longer, while the swing phase, stride length, walking speed, and moving ranges of the thigh, calf and foot of BW decreased (<it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Backward walking training in school-aged boys can improve balance.</p

    Anticipated and experienced discrimination amongst people with schizophrenia, bipolar disorder and major depressive disorder: a cross-sectional study.

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    BACKGROUND: The unfair treatment of individuals with severe mental illness has been linked to poorer physical and mental health outcomes. Additionally, anticipation of discrimination may lead some individuals to avoid participation in particular life areas, leading to greater isolation and social marginalisation. This study aimed to establish the levels and clinical and socio-demographic associations of anticipated and experienced discrimination amongst those diagnosed with a schizophrenia and comparator severe mental illnesses (bipolar and major depressive disorders). METHODS: This study was a cross-sectional analysis of anticipated and experienced discrimination from 202 individuals in South London (47% with schizophrenia, 32% with depression and 20% with bipolar disorder). RESULTS: 93% of the sample anticipated discrimination and 87% of participants had experienced discrimination in at least one area of life in the previous year. There was a significant association between the anticipation and the experience of discrimination. Higher levels of experienced discrimination were reported by those of a mixed ethnicity, and those with higher levels of education. Women anticipated more discrimination than men. Neither diagnosis nor levels of functioning were associated with the extent of discrimination. Clinical symptoms of anxiety, depression and suspiciousness were associated with more experienced and anticipated discrimination respectively. CONCLUSIONS: The unfair treatment of individuals with severe mental illnesses remains unacceptably common. Population level interventions are needed to reduce levels of discrimination and to safeguard individuals. Interventions are also required to assist those with severe mental illness to reduce internalised stigma and social avoidance

    Suboptimal Activation of Antigen-Specific CD4+ Effector Cells Enables Persistence of M. tuberculosis In Vivo

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    Adaptive immunity to Mycobacterium tuberculosis controls progressive bacterial growth and disease but does not eradicate infection. Among CD4+ T cells in the lungs of M. tuberculosis-infected mice, we observed that few produced IFN-γ without ex vivo restimulation. Therefore, we hypothesized that one mechanism whereby M. tuberculosis avoids elimination is by limiting activation of CD4+ effector T cells at the site of infection in the lungs. To test this hypothesis, we adoptively transferred Th1-polarized CD4+ effector T cells specific for M. tuberculosis Ag85B peptide 25 (P25TCRTh1 cells), which trafficked to the lungs of infected mice and exhibited antigen-dependent IFN-γ production. During the early phase of infection, ∼10% of P25TCRTh1 cells produced IFN-γ in vivo; this declined to <1% as infection progressed to chronic phase. Bacterial downregulation of fbpB (encoding Ag85B) contributed to the decrease in effector T cell activation in the lungs, as a strain of M. tuberculosis engineered to express fbpB in the chronic phase stimulated P25TCRTh1 effector cells at higher frequencies in vivo, and this resulted in CD4+ T cell-dependent reduction of lung bacterial burdens and prolonged survival of mice. Administration of synthetic peptide 25 alone also increased activation of endogenous antigen-specific effector cells and reduced the bacterial burden in the lungs without apparent host toxicity. These results indicate that CD4+ effector T cells are activated at suboptimal frequencies in tuberculosis, and that increasing effector T cell activation in the lungs by providing one or more epitope peptides may be a successful strategy for TB therapy

    Combined dynamics of mercury and terrigenous organic matter following impoundment of Churchill Falls Hydroelectric Reservoir, Labrador

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    Sediments from two recently (40 years) flooded lakes (Gabbro lake and Sandgirt lake) and an unflooded lake (Atikonak lake) were sampled to investigate the effects of reservoir impoundment on mercury (Hg) and terrigenous organic matter (TOM) loading in the Churchill Falls Hydroelectric complex in Labrador, Canada. Lignin biomarkers in TOM, which exclusively derive from terrestrial vegetation, were used as biomarkers for the presence and source origin of TOM—and for Hg due to their close associations—in sediments. In the two flooded Gabbro and Sandgirt lakes, we observed drastic increases in total mercury concentrations, T-[Hg], in sediments, which temporally coincided with the time of reservoir impoundment as assessed by 210Pb age dating. In the natural Atikonak lake sediments, on the other hand, T-[Hg] showed no such step-increase but gradually and slowly increased until present. T-[Hg] increases in lake sediments after flooding were also associated with a change in the nature of TOM: biomarker signatures changed to typical signatures of TOM from vegetated terrestrial landscape surrounding the lakes, and indicate a change to TOM that was much less degraded and typical of forest soil organic horizons. We conclude that T-[Hg] increase in the sediments of the two flooded reservoirs was the result of flooding of surrounding forests, whereby mainly surface organic horizons and upper soil horizons were prone to erosion and subsequent re-sedimentation in the reservoirs. The fact that T-[Hg] was still enriched 40 years after reservoir impoundment indicates prolonged response time of lake Hg and sediment loadings after reservoir impoundments

    l-Arginine stimulates proliferation and prevents endotoxin-induced death of intestinal cells

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    This study tested the hypothesis that l-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco’s modified Eagle’s-F12 Ham medium (DMEM-F12) containing 10, 100 or 350 μM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation, as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein concentrations in IPEC-1 cells. Addition of 100 and 350 μM Arg to culture medium dose-dependently attenuated LPS-induced cell death and reduction of protein concentrations, in comparison with the basal medium containing 10 μM Arg. Furthermore, supplementation of 100 and 350 μM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells. Consistent with the data on cell growth and protein turnover, addition of 100 or 350 μM Arg to culture medium increased relative protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels of TLR4 and phosphorylated levels of nuclear factor-κB in LPS-treated IPEC-1 cells. These results demonstrate a protective effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well as intracellular protein turnover
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