775 research outputs found

    Altered glomerular permeability induced by F(abâ€Č)2 and Fabâ€Č antibodies to rat renal tubular epithelial antigen

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    Altered glomerular permeability induced by F(abâ€Č)2 and Fabâ€Č antibodies to rat renal tubular epithelial antigen. Rats injected with F(abâ€Č)2 and Fabâ€Č antibody fragments directed against an antigen in the rat proximal tubular epithelial brushborder (Fx1A) developed immediate proteinuria [F(abâ€Č)2 43.2 ± 6.7, N = 6; Fabâ€Č 9.5 ± 2.8, N = 5; normal 1.6 ± 0.9 mg/day, N = 20]), that subsided after 3 to 5 days' duration. This reaction is in contrast to one exhibited by rats given intact IgG anti-Fx1A; the rats that did not develop immediate proteinuria (2.2 ± 0.3 mg/day, N = 5), and the glomerular binding of125I-antibody fragments was significantly less than that of intact IgG [F(abâ€Č)2 0.11 ± 0.01; Fabâ€Č 0.03 ± 0.01; IgG 0.17 ± 0.01% administered equimolar dose] at 24 hr. No proteinuria resulted from equimolar doses of nonantibody F(abâ€Č)2 and Fabâ€Č. Less than 8% of the proteinuria induced by antibody fragments represented injected material, and 30 to 38% was albumin. Immunofluorescence revealed faint and diffuse glomerular capillary wall deposits of F(abâ€Č)2 and Fabâ€Č and tubular brushborder staining. Subepithelial, electrondense deposits and focal, podocyte effacement were seen by electron microscopy in rats given the F(abâ€Č)2 antibody. Light microscopy and colloidal iron-staining were normal. In our study antibody fragments appear to interact directly with components of the outer, glomerular capillary wall to alter permeability in the absence of recognized mediators such as complement and inflammatory cells.Modification de la permĂ©abilitĂ© glomĂ©rulaire dĂ©terminĂ©e par anticorps chez des rats anti-Ă©pithĂ©lium tubulaire F(abâ€Č)2 et Fabâ€Č. Les rats Ă©tĂ© injectĂ©s avec des fragments F(abâ€Č)2 et Fabâ€Č contra anticorps de la bordure en brosse de l'Ă©pithĂ©lium tubulaire proximal de rat (Fx1A) ont immĂ©diatement une protĂ©inurie [F(abâ€Č)2 43,2 ± 6,7, N = 6; Fabâ€Č 9,5 ± 2,8, N = 5; normaux 1,6 ± 0,9 mg/d, N = 20] qui persiste pendant 3 Ă  5 jours. Cela rĂ©action est diffĂ©rent de ce qui est observĂ© chez les rats qui reçoivent l'IgG anti-Fx1A intacte; les rats quelles n'ont pas de protĂ©inurie immĂ©diate (2,2 ± 0,3 mg/d, N = 5) quoiqu'Ă  24 heures la liaison glomĂ©rulaire de fragments125I de l'anticorps soit significativement plus faible que celle de I'IgG intacte [F(abâ€Č)2 0,11 ± 0,01; Fabâ€Č 0,03 ± 0,01; IgG 0,17 ± 0,01 en % de la dose Ă©quimolaire administrĂ©e]. Aucune protĂ©inurie n'a Ă©tĂ© la consĂ©quence de l'administration Ă©quimolaire de F(abâ€Č)2 et Fabâ€Č non-anticorps. Moins de 8% de la protĂ©inurie dĂ©terminĂ©e par les fragments d'anticorps reprĂ©sentent du matĂ©riel injectĂ© et 30 Ă  38% est de l'albumine. L'immunofluorescence a montrĂ© des dĂ©pĂŽts faibles et diffus, sur les parois des capillaires giomĂ©rulaires, de F(abâ€Č)2 et Fabâ€Č et le marquage de la bordure en brosse. En Ă©lectronique, des dĂ©pĂŽts denses sous-Ă©pithĂ©liaux et l'effacement local des podocytes ont Ă©tĂ© observĂ©s chez les rats qui avaient reçu l'anticorps F(abâ€Č)2. La microscopie optique et la coloration par le fer colloĂŻdal n'ont pas montrĂ© d'anomalies. Dans notre Ă©tude les fragments d'anticorps semblent avoir paroi externe du capillaire glomĂ©rulaire et avoir modifiĂ© la permĂ©abilitĂ© en l'absence de mĂ©diateurs connus tels le complĂ©ment ou les cellules inflammatoires

    License prices for financially constrained firms

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    It is often alleged that high auction prices inhibit service deployment. We investigate this claim under the extreme case of financially constrained bidders. If demand is just slightly elastic, auctions maximize consumer surplus if consumer surplus is a convex function of quantity (a common assumption), or if consumer surplus is concave and the proportion of expenditure spent on deployment is greater than one over the elasticity of demand. The latter condition appears to be true for most of the large telecom auctions in the US and Europe. Thus, even if high auction prices inhibit service deployment, auctions appear to be optimal from the consumers’ point of view

    On the lease rate, convenience yield and speculative effects in the gold futures market

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    By examining data on the gold forward offered rate (GOFO) and lease rates over the period 1996- 2009, we conclude that the convenience yield of gold is better approximated by the lease rate than the interest-adjusted spread of Fama & French (1983). Using the latter quantity, we study the relationship between gold leasing and the level of COMEX discretionary inventory and exhibit that lease rates are negatively related to inventories. We also show that Futures prices have increasingly exceeded forward prices over the period, and this effect increases with the speculative pressure and the maturity of the contracts

    How do women at increased, but unexplained, familial risk of breast cancer perceive and manage their risk? A qualitative interview study

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    <p>Abstract</p> <p>Background</p> <p>The perception of breast cancer risk held by women who have not had breast cancer, and who are at increased, but unexplained, familial risk of breast cancer is poorly described. This study aims to describe risk perception and how it is related to screening behaviour for these women.</p> <p>Methods</p> <p>Participants were recruited from a population-based sample (the Australian Breast Cancer Family Study - ABCFS). The ABCFS includes women diagnosed with breast cancer and their relatives. For this study, women without breast cancer with at least one first- or second-degree relative diagnosed with breast cancer before age 50 were eligible unless a <it>BRCA1 </it>or <it>BRCA2 </it>mutation had been identified in their family. Data collection consisted of an audio recorded, semi-structured interview on the topic of breast cancer risk and screening decision-making. Data was analysed thematically.</p> <p>Results</p> <p>A total of 24 interviews were conducted, and saturation of the main themes was achieved. Women were classified into one of five groups: don't worry about cancer risk, but do screening; concerned about cancer risk, so do something; concerned about cancer risk, so why don't I do anything?; cancer inevitable; cancer unlikely.</p> <p>Conclusions</p> <p>The language and framework women use to describe their risk of breast cancer must be the starting point in attempts to enhance women's understanding of risk and their prevention behaviour.</p

    Load carrying capacity of a heterogeneous surface bearing

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    It has been shown before that liquids can slip at a solid boundary, which prompted the idea that parallel-surfaces bearings can be achieved just by alternating slip and non-slip regions in the direction of fluid flow. The amount of slip at the wall depends on the surface tension at the liquid–solid interface, which in turn depends on the chemical state of the surface and its roughness. In the present study a heterogeneous surface was obtained by coating half of a circular glass disc with a coating repellant to glycerol. A rotating glass disc was placed at a known/calibrated distance and the gap was filled with glycerol. With the mobile surface moving from the direction of slip to non-slip region it can be theoretically shown that a pressure build up can be achieved. The pressure gradient in the two regions is constant, similar to that in a Rayleigh step bearing, with the maximum pressure at the separation line. The heterogeneous disc was placed on a holder supported by a load cell thus the force generated by this pressure increase can be measured accurately. Tests were carried out at different sliding speeds and gaps and the load carried was measured and subsequently compared with theoretical calculations. This allowed the slip coefficient to be evaluated
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