89 research outputs found

    Fstl1 Antagonizes BMP Signaling and Regulates Ureter Development

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    Bone morphogenetic protein (BMP) signaling pathway plays important roles in urinary tract development although the detailed regulation of its activity in this process remains unclear. Here we report that follistatin-like 1 (Fstl1), encoding a secreted extracellular glycoprotein, is expressed in developing ureter and antagonizes BMP signaling activity. Mouse embryos carrying disrupted Fstl1 gene displayed prominent hydroureter arising from proximal segment and ureterovesical junction defects. These defects were associated with significant reduction in ureteric epithelial cell proliferation at E15.5 and E16.5 as well as absence of subepithelial ureteral mesenchymal cells in the urinary tract at E16.5 and E18.5. At the molecular level, increased BMP signaling was found in Fstl1 deficient ureters, indicated by elevated pSmad1/5/8 activity. In vitro study also indicated that Fstl1 can directly bind to ALK6 which is specifically expressed in ureteric epithelial cells in developing ureter. Furthermore, Sonic hedgehog (SHH) signaling, which is crucial for differentiation of ureteral subepithelial cell proliferation, was also impaired in Fstl1-/- ureter. Altogether, our data suggest that Fstl1 is essential in maintaining normal ureter development by antagonizing BMP signaling

    Impact of Integrated Services on HIV Testing: A Nonrandomized Trial among Kenyan Family Planning Clients.

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    The impact of integrated reproductive health and HIV services on HIV testing and counseling (HTC) uptake was assessed among 882 Kenyan family planning clients using a nonrandomized cohort design within six intervention and six "comparison" facilities. The effect of integration on HTC goals (two tests over two years) was assessed using conditional logistic regression to test four "integration" exposures: a training and reorganization intervention; receipt of reproductive health and HIV services at recruitment; a functional measure of facility integration at recruitment; and a woman's cumulative exposure to functionally integrated care across different facilities over time. While recent receipt of HTC increased rapidly at intervention facilities, achievement of HTC goals was higher at comparison facilities. Only high cumulative exposure to integrated care over two years had a significant effect on HTC goals after adjustment (aOR 2.94, 95%CI 1.73-4.98), and programs should therefore make efforts to roll out integrated services to ensure repeated contact over time

    Genetic approaches to human renal agenesis/hypoplasia and dysplasia

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    Congenital abnormalities of the kidney and urinary tract are frequently observed in children and represent a significant cause of morbidity and mortality. These conditions are phenotypically variable, often affecting several segments of the urinary tract simultaneously, making clinical classification and diagnosis difficult. Renal agenesis/hypoplasia and dysplasia account for a significant portion of these anomalies, and a genetic contribution to its cause is being increasingly recognized. Nevertheless, overlap between diseases and challenges in clinical diagnosis complicate studies attempting to discover new genes underlying this anomaly. Most of the insights in kidney development derive from studies in mouse models or from rare, syndromic forms of human developmental disorders of the kidney and urinary tract. The genes implicated have been shown to regulate the reciprocal induction between the ureteric bud and the metanephric mesenchyme. Strategies to find genes causing renal agenesis/hypoplasia and dysplasia vary depending on the characteristics of the study population available. The approaches range from candidate gene association or resequencing studies to traditional linkage studies, using outbred pedigrees or genetic isolates, to search for structural variation in the genome. Each of these strategies has advantages and pitfalls and some have led to significant discoveries in human disease. However, renal agenesis/hypoplasia and dysplasia still represents a challenge, both for the clinicians who attempt a precise diagnosis and for the geneticist who tries to unravel the genetic basis, and a better classification requires molecular definition to be retrospectively improved. The goal appears to be feasible with the large multicentric collaborative groups that share the same objectives and resources

    PHOTOCHEMISTRY OF FORMALDEHYDE

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    Author Institution: School of Chemistry, University of BristolThe HOxHO_{x} family (OH and HO2HO_{2}) is central to the photochemistry of the atmosphere. Recent measurement campaigns have revealed HOxHO_{x} concentrations much greater than predicted by models using only water, methane and ozone chemistry. Formaldehyde is now recognized as an important source of HOxHO_{x} in the upper troposphere. The photodissociation of formaldehyde by sunlight can occur through two distinct and competing channels: H2CO+hΞ½β†’H2+COH2CO+hΞ½β†’HCO+HH_{2}CO + h\nu \rightarrow H_{2} + CO H_{2}CO + h\nu \rightarrow HCO + H The second channel produces radicals that, after subsequent reaction with O2O_{2}, form HOxHO_{x}. This project investigates the HOxHO_{x} production from the photochemistry of formaldehyde. To achieve this high resolution absorption cross section data for formaldehyde and formaldehyde quantum yields for the production of HCO are needed over a wavelength range and conditions of temperature and pressure appropriate to the upper troposphere. The data are then introduced into atmospheric models to predict the importance of formaldehyde in the upper tropospheric region
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