449 research outputs found

    Male pygmy hippopotamus influence offspring sex ratio

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    Pre-determining fetal sex is against the random and equal opportunity that both conceptus sexes have by nature. Yet, under a wide variety of circumstances, populations shift their birth sex ratio from the expected unity. Here we show, using fluorescence in situ hybridization, that in a population of pygmy hippopotamus (Choeropsis liberiensis) with 42.5% male offspring, males bias the ratio of X- and Y-chromosome-bearing spermatozoa in their ejaculates, resulting in a 0.4337±0.0094 (mean±s.d.) proportion of Y-chromosome-bearing spermatozoa. Three alternative hypotheses for the shifted population sex ratio were compared: female counteract male, female indifferent, or male and female in agreement. We conclude that there appears little or no antagonistic sexual conflict, unexpected by prevailing theories. Our results indicate that males possess a mechanism to adjust the ratio of X- and Y-chromosome-bearing spermatozoa in the ejaculate, thereby substantially expanding currently known male options in sexual conflict

    Accuracy of Malaria Rapid Diagnostic Tests in Community Studies and their Impact on Treatment of Malaria in an Area with Declining Malaria Burden in North-Eastern Tanzania.

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    Despite some problems related to accuracy and applicability of malaria rapid diagnostic tests (RDTs), they are currently the best option in areas with limited laboratory services for improving case management through parasitological diagnosis and reducing over-treatment. This study was conducted in areas with declining malaria burden to assess; 1) the accuracy of RDTs when used at different community settings, 2) the impact of using RDTs on anti-malarial dispensing by community-owned resource persons (CORPs) and 3) adherence of CORPs to treatment guidelines by providing treatment based on RDT results. Data were obtained from: 1) a longitudinal study of passive case detection of fevers using CORPs in six villages in Korogwe; and 2) cross-sectional surveys (CSS) in six villages of Korogwe and Muheza districts, north-eastern, Tanzania. Performance of RDTs was compared with microscopy as a gold standard, and factors affecting their accuracy were explored using a multivariate logistic regression model. Overall sensitivity and specificity of RDTs in the longitudinal study (of 23,793 febrile cases; 18,154 with microscopy and RDTs results) were 88.6% and 88.2%, respectively. In the CSS, the sensitivity was significantly lower (63.4%; χ2=367.7, p<0.001), while the specificity was significantly higher (94.3%; χ2=143.1, p<0.001) when compared to the longitudinal study. As determinants of sensitivity of RDTs in both studies, parasite density of<200 asexual parasites/μl was significantly associated with high risk of false negative RDTs (OR≥16.60, p<0.001), while the risk of false negative test was significantly lower among cases with fever (axillary temperature ≥37.5 °C) (OR≤0.63, p≤0.027). The risk of false positive RDT (as a determinant of specificity) was significantly higher in cases with fever compared to afebrile cases (OR≥2.40, p<0.001). Using RDTs reduced anti-malarials dispensing from 98.9% to 32.1% in cases aged ≥5 years. Although RDTs had low sensitivity and specificity, which varied widely depending on fever and parasite density, using RDTs reduced over-treatment with anti-malarials significantly. Thus, with declining malaria prevalence, RDTs will potentially identify majority of febrile cases with parasites and lead to improved management of malaria and non-malaria fevers

    Natural images from the birthplace of the human eye

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    Here we introduce a database of calibrated natural images publicly available through an easy-to-use web interface. Using a Nikon D70 digital SLR camera, we acquired about 5000 six-megapixel images of Okavango Delta of Botswana, a tropical savanna habitat similar to where the human eye is thought to have evolved. Some sequences of images were captured unsystematically while following a baboon troop, while others were designed to vary a single parameter such as aperture, object distance, time of day or position on the horizon. Images are available in the raw RGB format and in grayscale. Images are also available in units relevant to the physiology of human cone photoreceptors, where pixel values represent the expected number of photoisomerizations per second for cones sensitive to long (L), medium (M) and short (S) wavelengths. This database is distributed under a Creative Commons Attribution-Noncommercial Unported license to facilitate research in computer vision, psychophysics of perception, and visual neuroscience.Comment: Submitted to PLoS ON

    Effect of surfactant replacement on Pneumocystis carinii pneumonia in rats

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    The effect of intratracheal surfactant instillation on pulmonary function in rats with Pneumocystis carinii pneumonia (PCP) was investigated. In those animals which developed PCP with severe respiratory failure after administration of cortisone acetate s. c. over 8-12 weeks, pulmonary function was improved by surfactant instillation. PaO2 values 30 min after surfactant instillation were significantly higher compared to pretreatment values and also compared to PaO2 values of rats 30 min after receiving saline (482.9 mmHg±44.7, 170.7 mmHg ±39.3 and 67.2 mmHg±17.4, respectively). Histological examination showed that alveoli of rats with PCP which received no exogenous surfactant are filled with foamy edema, whereas after exogenous surfactant alveoli are stabilized and well-aerated. These results indicate that exogenous surfactant may help patients with severe PCP to overcome an acute stage of respiratory distress

    Requirement of CHROMOMETHYLASE3 for somatic inheritance of the spontaneous tomato epimutation Colourless non-ripening

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    Naturally-occurring epimutants are rare and have mainly been described in plants. However how these mutants maintain their epigenetic marks and how they are inherited remain unknown. Here we report that CHROMOMETHYLASE3 (SlCMT3) and other methyltransferases are required for maintenance of a spontaneous epimutation and its cognate Colourless non-ripening (Cnr) phenotype in tomato. We screened a series of DNA methylation-related genes that could rescue the hypermethylated Cnr mutant. Silencing of the developmentally-regulated SlCMT3 gene results in increased expression of LeSPL-CNR, the gene encodes the SBP-box transcription factor residing at the Cnr locus and triggers Cnr fruits to ripen normally. Expression of other key ripening-genes was also up-regulated. Targeted and whole-genome bisulfite sequencing showed that the induced ripening of Cnr fruits is associated with reduction of methylation at CHG sites in a 286-bp region of the LeSPL-CNR promoter, and a decrease of DNA methylation in differentially-methylated regions associated with the LeMADS-RIN binding sites. Our results indicate that there is likely a concerted effect of different ethyltransferases at the Cnr locus and the plant-specific SlCMT3 is essential for sustaining Cnr epi-allele. Maintenance of DNA methylation dynamics is critical for the somatic stability of Cnr epimutation and for the inheritance of tomato non-ripening phenotype

    Outcome of primary resurfacing hip replacement: evaluation of risk factors for early revision: 12,093 replacements from the Australian Joint Registry

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    BACKGROUND AND PURPOSE: The outcome of modern resurfacing remains to be determined. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) started collection of data on hip resurfacing at a time when modern resurfacing was started in Australia. The rate of resurfacing has been higher in Australia than in many other countries. As a result, the AOANJRR has one of the largest series of resurfacing procedures. This study was undertaken to determine the results of this series and the risk factors associated with revision. PATIENTS AND METHODS: Data from the AOANJRR were used to analyze the survivorship of 12,093 primary resurfacing hip replacements reported to the Joint Replacement Registry between September 1999 and December 2008. This was compared to the results of primary conventional total hip replacement reported during the same period. The Kaplan-Meier method and proportional hazards models were used to determine risk factors such as age, sex, femoral component size, primary diagnosis, and implant design. RESULTS: Female patients had a higher revision rate than males; however, after adjusting for head size, the revision rates were similar. Prostheses with head sizes of less than 50 mm had a higher revision rate than those with head sizes of 50 mm or more. At 8 years, the cumulative per cent revision of hip resurfacing was 5.3 (4.6-6.2), as compared to 4.0 (3.8-4.2) for total hip replacement. However, in osteoarthritis patients aged less than 55 years with head sizes of 50 mm or more, the 7-year cumulative per cent revision for hip resurfacing was 3.0 (2.2-4.2). Also, hips with dysplasia and some implant designs had an increased risk of revision. INTERPRETATION: Risk factors for revision of resurfacing were older patients, smaller femoral head size, patients with developmental dysplasia, and certain implant designs. These results highlight the importance of patient and prosthesis selection in optimizing the outcome of hip resurfacing

    Inhibition of SLPI ameliorates disease activity in experimental autoimmune encephalomyelitis

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    <p>Abstract</p> <p>Background</p> <p>The secretory leukocyte protease inhibitor (SLPI) exerts wide ranging effects on inflammatory pathways and is upregulated in EAE but the biological role of SLPI in EAE, an animal model of multiple sclerosis is unknown</p> <p>Methods</p> <p>To investigate the pathophysiological effects of SLPI within EAE, we induced SLPI-neutralizing antibodies in mice and rats to determine the clinical severity of the disease. In addition we studied the effects of SLPI on the anti-inflammatory cytokine TGF-β.</p> <p>Results</p> <p>The induction of SLPI neutralizing antibodies resulted in a milder disease course in mouse and rat EAE. SLPI neutralization was associated with increased serum levels of TGF-β and increased numbers of FoxP3+ CD4+ T cells in lymph nodes. <it>In vitro</it>, the addition of SLPI significantly decreased the number of functional FoxP3+ CD25<sup>hi </sup>CD4+ regulatory T cells in cultures of naive human CD4+ T cells. Adding recombinant TGF-β to SLPI-treated human T cell cultures neutralized SLPI's inhibitory effect on regulatory T cell differentiation.</p> <p>Conclusion</p> <p>In EAE, SLPI exerts potent pro-inflammatory actions by modulation of T-cell activity and its neutralization may be beneficial for the disease.</p

    The positive impact of a facilitated peer mentoring program on academic skills of women faculty

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    <p>Abstract</p> <p>Background</p> <p>In academic medicine, women physicians lag behind their male counterparts in advancement and promotion to leadership positions. Lack of mentoring, among other factors, has been reported to contribute to this disparity. Peer mentoring has been reported as a successful alternative to the dyadic mentoring model for women interested in improving their academic productivity. We describe a facilitated peer mentoring program in our institution's department of medicine.</p> <p>Methods</p> <p>Nineteen women enrolled in the program were divided into 5 groups. Each group had an assigned facilitator. Members of the respective groups met together with their facilitators at regular intervals during the 12 months of the project. A pre- and post-program evaluation consisting of a 25-item self-assessment of academic skills, self-efficacy, and academic career satisfaction was administered to each participant.</p> <p>Results</p> <p>At the end of 12 months, a total of 9 manuscripts were submitted to peer-reviewed journals, 6 of which are in press or have been published, and another 2 of which have been invited to be revised and resubmitted. At the end of the program, participants reported an increase in their satisfaction with academic achievement (mean score increase, 2.32 to 3.63; <it>P </it>= 0.0001), improvement in skills necessary to effectively search the medical literature (mean score increase, 3.32 to 4.05; <it>P </it>= 0.0009), an improvement in their ability to write a comprehensive review article (mean score increase, 2.89 to 3.63; <it>P </it>= 0.0017), and an improvement in their ability to critically evaluate the medical literature (mean score increased from 3.11 to 3.89; <it>P </it>= 0.0008).</p> <p>Conclusions</p> <p>This facilitated peer mentoring program demonstrated a positive impact on the academic skills and manuscript writing for junior women faculty. This 1-year program required minimal institutional resources, and suggests a need for further study of this and other mentoring programs for women faculty.</p

    Improved HIV and Substance Abuse Treatment Outcomes for Released HIV-Infected Prisoners: The Impact of Buprenorphine Treatment

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    HIV-infected prisoners fare poorly after release. Though rarely available, opioid agonist therapy (OAT) may be one way to improve HIV and substance abuse treatment outcomes after release. Of the 69 HIV-infected prisoners enrolled in a randomized controlled trial of directly administered antiretroviral therapy, 48 (70%) met DSM-IV criteria for opioid dependence. Of these, 30 (62.5%) selected OAT, either as methadone (N = 7, 14.5%) or buprenorphine/naloxone (BPN/NLX; N = 23, 48.0%). Twelve-week HIV and substance abuse treatment outcomes are reported as a sub-study for those selecting BPN/NLX. Retention was high: 21 (91%) completed BPN/NLX induction and 17 (74%) remained on BPN/NLX after 12 weeks. Compared with baseline, the proportion with a non-detectable viral load (61% vs 63% log10 copies/mL) and mean CD4 count (367 vs 344 cells/mL) was unchanged at 12 weeks. Opiate-negative urine testing remained 83% for the 21 who completed induction. Using means from 10-point Likert scales, opioid craving was reduced from 6.0 to 1.8 within 3 days of BPN/NLX induction and satisfaction remained high at 9.5 throughout the 12 weeks. Adverse events were few and mild. BPN/NLX therapy was acceptable, safe and effective for both HIV and opioid treatment outcomes among released HIV-infected prisoners. Future randomized controlled trials are needed to affirm its benefit in this highly vulnerable population
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