994 resultados para Kidney volume
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Background: Cytomegalovirus (CMV) disease remains an important cause of morbidity after kidney transplantation and has been associated with acute rejection, graft loss and other indirect effects. A 3-month course of VGC prophylaxis reduces the incidence of CMV disease. However, little is known about the indirect effects of lateonset CMV disease after VGC prophylaxis. Objective: To evaluate the impact and indirect consequences of late-onset CMV disease after VGC prophylaxis in kidney transplant recipients. Methods: Retrospective analysis of 61 consecutive adult kidney transplant recipient with positive CMV serology (donor or recipient) who received VGC prophylaxis for 3 months and completed a follow-up of at least 2 years post-transplantation. Patients who developed CMV disease within 1 year after transplantation were compared to CMV disease-free patients for renal function (plasma creatinine values) at 1, 6, 12 and 24 months and for the incidence of graft loss, acute rejection, diabetes, cancer and opportunistic infections. Results: 8/61 (13%) patients developed CMV disease at a median of 131 days after transplantation (range: 98-220). The CMV incidence in D+/R- high risk patients was 6/18 (33%), while it was 2/43 (5%) in intermediate-risk patients (p < 0.01). All 8 patients were treated by oral valganciclovir (median 39 days; range: 19-119) with a complete resolution of CMV disease. As shown in the figure, there was no difference in creatinine values between the two groups at any time during follow-up. There was no graft loss, and the incidence of acute rejection, cancer and opportunistic infections did not differ between the two groups. The incidence of post-transplant diabetes was higher (38% vs 15%) in patients with CMV disease, but this difference was not significant (p = 0.4). Conclusions: An incidence of 13% of late-onset CMV disease was observed despite 3 months VGC prophylaxis. However, no indirect consequences were found. Moreover, therapy of CMV disease by oral VGC was effective and safe. Larger trials are needed to study whether late-onset CMV disease is associated with indirect consequences, as described with early-onset CMV.
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Dans les cellules épithéliales sensibles à l'aldostérone, le canal sodique épithélial (ENaC) joue un rôle critique dans le contrôle de l'équilibre sodique, le volume sanguin, et la pression sanguine. Le rôle d'ENaC est bien caractérisé dans le rein et les poumons, cependant le rôle d'ENaC et son régulateur positif la protéase activatrice de canal 1 (CAP1 /Prss8) sur le transport sodique dans le côlon reste en grande partie inconnu. Nous avons étudié l'importance d'ENaC et de CAPMPrss8 dans le côlon. Les souris déficientes pour la sous- unité aENaC (souris ScnnlaKO) dans les cellules superficielles intestinales étaient viables et ne montraient pas de létalité embryonnaire ou postnatale. Sous diète normale (RS) ou pauvre en sodium (LS), la différence de potentiel rectale sensible à l'amiloride (APDamii) était drastiquement diminuée et son rythme circadien atténué. Sous diète normale (RS) ou diète riche en sodium (HS) ou fort chargement de potassium, le sodium et le potassium plasmatique et urinaire n'étaient pas significativement changé. Cependant, sous LS, les souris Senni aK0 perdaient des quantités significativement augmentées de sodium dans leurs fèces, accompagnées par de très hauts taux d'aldostérone plasmatique et une rétention urinaire en sodium augmentée. Les souris déficientes en CAPl/PmS (Prss8K0) dans les cellules superficielles intestinales étaient viables et ne montraient pas de létalité embryonnaire ou postnatale. Sous diètes RS et HS cependant, les souris Prss8KO montraient une diminution significative du APDamil dans l'après-midi, mais le rythme circadien était maintenu. Sous diète LS, la perte de sodium par les fèces était accompagnée par des niveaux d'aldostérone plasmatiques plus élevés. Par conséquent, nous avons identifié la protéase activatrice de canal CAP 1 IPrss8 comme un régulateur important d'ENaC dans le côlon in vivo. De plus, nous étudions l'importance d'ENaC et de CAPIIPrss8 dans les conditions pathologiques comme les maladies inflammatoires chroniques de l'intestin (MICI). Le résultat préliminaire out montre qu'une déficience d'Prss8 mènait à la détérioration de la colite induite par le DSS comparé aux modèles contrôles respectifs. En résumé, l'étude a montré que sous restriction de sel, l'absence d'ENaC dans Pépithélium de surface du côlon était compensée par 1'activation du système rénine-angiotensine- aldostérone (RAAS) dans le rein. Ceci a mené à un pseudohypoaldostéronisme de type I spécifique au côlon avec résistance aux minéralocorticoïdes sans signe d'altération de rétention de potassium. - In aldosterone-responsive epithelial cells of kidney and colon, the epithelial sodium channel (ENaC) plays a critical role in the control of sodium balance, blood volume, and blood pressure. The role of ENaC is well characterized in kidney and lung, whereas role of ENaC and its positive regulator channel-activating protease 1 (CAPl/PrasS) on sodium transport in colon is largely unknown. We have investigated the importance of ENaC and CAPI/Prss8 in colon for sodium and potassium balance. Mice lacking the aENaC subunit (Scnnla mice) in intestinal superficial cells were viable and did not show any fetal or perinatal lethality. Under regular (RS) or low salt (LS) diet, the amiloride sensitive rectal potential difference (APDamii) was drastically decreased and its circadian rhythm blunted. Under regular salt (RS) or high salt (HS) diets or under potassium loading, plasma and urinary sodium and potassium were not significantly changed. However, upon LS, the ScnnlaK0 mice lost significant amounts of sodium in their feces, accompanied by very high plasma aldosterone and increased urinary sodium retention. Mice lacking the CAPl/PrasS (Prss8K0) in intestinal superficial cells were viable and did not show any fetal or perinatal lethality. Upon RS and HS diets, however, Prss8K0 exhibited a significantly reduced APDamii in the afternoon, but its circadian rhythm was maintained. Upon LS diet, sodium loss through feces was accompanied by higher plasma aldosterone levels. Thus, we have identified the channel-activating protease CAPl/Prss8 as an important in vivo regulator of ENaC in colon. Furthermore, we are investigating the importance of ENaC and CAPI/Prss8 in pathological conditions like inflammatory bowel disease (IBD). Preliminary data showed that PmS-deficiency led to worsening of DSS-induced colitis as compared to their respective controls. Overall, the present study has shown that under salt restriction, the absence of ENaC in colonic surface epithelium was compensated by the activation of renin-angiotensin- aldosterone (RAAS) system in the kidney. This led to a colon specific pseudohypoaldosteroni sm type 1 with mineralocorticoid resistance without evidence of impaired potassium retention.
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This final report for Phase 1 of the research on epoxy-coated, prestressing strands in precast prestressed concrete (PC) panels has been published in two volumes. This volume, Volume 1--Technical Report, contains the problem description, literature review, and survey results; descriptions of the test specimens, experimental tests, and analytical models; discussions of the analytical and experimental results; summary, conclusions, and recommendations; list of references; and acknowledgment. Volume 2--Supplemental Report contains additional information in the form of summarized responses to the questionnaires; graphs showing the strand forces; figures showing the geometry of the specimens and concrete crack patterns that formed in the strand transfer length and strand development length specimens; and graphs of the concrete strains in the strand transfer length specimens, load-point deflections, and strand-slip measurements for the strand development length specimens.
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Recent reports have indicated that 23.5% of the nation's highway bridges are structurally deficient and 17.7% are functionally obsolete. A significant number of these bridges are on the Iowa secondary road system where over 86% of the rural bridge management responsibilities are assigned to the counties. Some of the bridges can be strengthened or otherwise rehabilitated, but many more are in need of immediate replacement. In a recent investigation (HR-365 "Evaluation of Bridge Replacement Alternatives for the County Bridge System") several types of replacement bridges that are currently being used on low volume roads were identified. It was also determined that a large number of counties (69%) have the ability and are interested in utilizing their own forces to design and construct short span bridges. After reviewing the results from HR-365, the research team developed one "new" bridge replacement concept and a modification of a replacement system currently being used. Both of these bridge replacement alternatives were investigated in this study, the results of which are presented in two volumes. This volume (Volume 2) presents the results of Concept 2 - Modification of the Beam-in-Slab Bridge. Concept 1 - Steel Beam Precast Units is presented in Volume 1. Concept 2 involves various laboratory tests of the Beam-in-Slab bridge (BISB) currently being used by Benton County and several other Iowa counties. In this investigation, the behavior and strength of the BISB were determined; a new method of obtaining composite action between the steel beams and concrete was also tested. Since the Concept 2 bridge is primarily intended for use on low-volume roads, the system can be constructed with new or used beams. In the experimental part of the investigation, there were three types of laboratory tests: push-out tests, service and ultimate load tests of models of the BISB, and composite beam tests utilizing the newly developed shear connection. In addition to the laboratory tests, there was a field test in which an existing BISB was service load tested. An equation was developed for predicting the strength of the shear connection investigated; in addition, a finite element model for analyzing the BISB was also developed. Push-out tests were completed to determine the strength of the recently developed shear connector. A total of 36 specimens were tested, with variables such as hole diameter, hole spacing, presence of reinforcement, etc. being investigated. In the model tests of the BISB, two and four beam specimens [L=9,140 mm (30 ft)] were service load tested for behavior and load distribution data. Upon completion of these tests, both specimens were loaded to failure. In the composite beam tests, four beams, one with standard shear studs and three using the shear connection developed, were tested. Upon completion of the service load tests, all four beams were loaded to failure. The strength and behavior of the beams with the new shear connection were found to be essentially the same as that of the specimen with standard shear studs.
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Abstract
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Abstract In humans, the skin is the largest organ of the body, covering up to 2m2 and weighing up to 4kg in an average adult. Its function is to preserve the body from external insults and also to retain water inside. This barrier function termed epidermal permeability barrier (EPB) is localized in the functional part of the skin: the epidermis. For this, evolution has built a complex structure of cells and lipids sealing the surface, the stratum corneum. The formation of this structure is finely tuned since it is not only formed once at birth, but renewed all life long. This active process gives a high plasticity and reactivity to skin, but also leads to various pathologies. ENaC is a sodium channel extensively studied in organs like kidney and lung due to its importance in regulating sodium homeostasis and fluid volume. It is composed of three subunits α, ß and r which are forming sodium selective channel through the cell membrane. Its presence in the skin has been demonstrated, but little is known about its physiological role. Previous work has shown that αENaC knockout mice displayed an abnormal epidermis, suggesting a role in differentiation processes that might be implicated in the EPB. The principal aim of this thesis has been to study the consequences for EPB function in mice deficient for αENaC by molecular and physiological means and to investigate the underlying molecular mechanisms. Here, the barrier function of αENaC knockout pups is impaired. Apparently not immediately after birth (permeability test) but 24h later, when evident water loss differences appeared compared to wildtypes. Neither the structural proteins of the epithelium nor the tights junctions showed any obvious alterations. In contrary, stratum corneum lipid disorders are most likely responsible for the barrier defect, accompanied by an impairment of skin surface acidification. To analyze in details this EPB defect, several hypotheses have been proposed: reduced sensibility to calcium which is the key activator far epidermal formation, or modification of ENaC-mediated ion fluxes/currents inside the epidermis. The cellular localization of ENaC and the action in the skin of CAPl, a positive regulator of ENaC, have been also studied in details. In summary, this study clearly demonstrates that ENaC is a key player in the EPB maintenance, because αENaC knockout pups are not able to adapt to the new environment (ex utero) as efficiently as the wildtypes, most likely due to impaired of sodium handling inside the epidermis. Résumé Chez l'homme, la peau est le plus grand organe, couvrant presque 2m2 et pesant près de 4kg chez l'adulte. Sa fonction principale est de protéger l'organisme des agressions extérieures mais également de conserver l'eau à l'intérieur du corps. Cette fonction nommée barrière épithéliale est localisée dans la partie fonctionnelle de la peau : l'épiderme. A cette fin, l'évolution s'est dotée d'une structure complexe composée de cellules et de lipides recouvrant la surface, la couche cornée. Sa formation est finement régulée, car elle n'est pas seulement produite à la naissance mais constamment renouvelée tout au long de la vie, ce qui lui confère une grande plasticité mais ce qui est également la cause de nombreuses pathologies. ENaC est un canal sodique très étudié dans le rein et le poumon pour son importance dans la régulation de l'homéostasie sodique et la régulation du volume du milieu intérieur. Il est composé de 3 sous unités, α, ß et y qui forment un pore sélectif pour le sodium dans les membranes. Ce canal est présent dans la peau mais sa fonction n'y est pas connue. Des travaux précédents ont pu montrer que les souris dont le gène codant pour αENaC a été invalidé présentent un épiderme pathologique, suggérant un rôle dans la différentiation et pourrait même être impliqué dans la barrière épithéliale. Le but de cette thèse fut l'étude de la barrière dans ces souris knockouts avec des méthodes moléculaires et physiologiques et la caractérisation des mécanismes moléculaire impliqués. Dans ce travail, il a été montré que les souris mutantes présentaient un défaut de la barrière. Ce défaut n'est pas visible immédiatement à la naissance (test de perméabilité), mais 24h plus tard, lorsque les tests de perte d'eau transépithéliale montrent une différence évidente avec les animaux contrôles. Ni les protéines de structures ni les jonctions serrées de l'épiderme ne présentaient d'imperfections majeures. A l'inverse, les lipides de la couche cornée présentaient un problème de maturation (expliquant le phénotype de la barrière), certainement consécutif au défaut d'acidification à la surface de la peau que nous avons observé. D'autres mécanismes ont été explorées afin d'investiguer cette anomalie de la barrière, comme la réduction de sensibilité au calcium qui est le principal activateur de la formation de l'épiderme, ou la modification des flux d'ions entre les couches de l'épiderme. La localisation cellulaire d'ENaC, et l'action de son activateur CAPl ont également été étudiés en détails. En résumé, cette étude démontre clairement qu'ENaC est un acteur important dans la formation de la barrière épithéliale, car la peau des knockouts ne s'adapte pas aussi bien que celle des sauvages au nouvel environnement ex utero à cause de la fonction d'ENaC dans les mouvements de sodium au sein même de l'épiderme. Résumé tout public Chez l'homme, la peau est le plus grand organe, couvrant presque 2m2 et pesant près de 4kg chez l'adulte. Sa fonction principale est de protéger l'organisme des agressions extérieures mais également de conserver l'eau à l'intérieur du corps. Cette fonction nommée barrière épithéliale est localisée dans la partie fonctionnelle de la peau : l'épiderme. A cette fin, l'évolution s'est dotée d'une structure complexe composée de cellules et de lipides recouvrant la surface, la couche cornée. Sa formation est finement régulée, car elle n'est pas seulement produite à la naissance mais constamment renouvelée tout au long de la vie, ce qui lui confère une grande plasticité mais ce qui est également la cause de nombreuses maladies. ENaC est une protéine formant un canal qui permet le passage sélectif de l'ion sodium à travers la paroi des cellules. Il est très étudié dans le rein pour son importance dans la récupération du sel lors de la concentration de l'urine. Ce canal est présent dans la peau mais sa fonction n'y est pas connue. Des travaux précédents ont pu montrer que les souris où le gène codant pour αENaC a été invalidé présentent un épiderme pathologique, suggérant un rôle dans la peau et plus particulièrement la fonction de barrière de l'épiderme. Le but de cette thèse fut l'étude de la fonction de barrière dans ces souris mutantes, au niveau tissulaire et cellulaire. Dans ce travail, il a été montré que les souris mutantes présentaient une peau plus perméable que celle des animaux contrôles, grâce à une machine mesurant la perte d'eau à travers la peau. Ce défaut n'est visible que 24h après la naissance, mais nous avons pu montrer que les animaux mutants perdaient quasiment 2 fois plus d'eau que les contrôles. Au niveau moléculaire, nous avons pu montrer que ce défaut provenait d'un problème de maturation des lipides qui composent la barrière de la peau. Cette maturation est incomplète vraisemblablement à cause d'un défaut de mouvement des ions dans les couches les plus superficielles de l'épiderme, et cela à cause de l'absence du canal ENaC. En résumé, cette étude démontre clairement qu'ENaC est un acteur important dans la formation de la barrière épithéliale, car la peau des mutants ne s'adapte pas aussi bien que celle des sauvages au nouvel environnement ex utero à cause de la fonction d'ENaC dans les mouvements de sodium au sein même de l'épiderme.
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This project continues the research which addresses the numerous bridge problems on the Iowa secondary road system. It is a continuation (Phase 2) of Project HR-382, in which two replacement alternatives (Concept 1: Steel Beam Precast Units and Concept 2: Modification of the Benton County Beam-in-Slab Bridge) were investigated. In previous research for concept 1, a precast unit bridge was developed through laboratory testing. The steel-beam precast unit bridge requires the fabrication of precast double-tee (PCDT) units, each consisting of two steel beams connected by a reinforced concrete deck. The weight of each PCDT unit is minimized by limiting the deck thickness to 4 in., which permits the units to be constructed off-site and then transported to the bridge site. The number of units required is a function of the width of bridge desired. Once the PCDT units are connected, a cast-in-place reinforced concrete deck is cast over the PCDT units and the bridge railing attached. Since the steel beam PCDT unit bridge design is intended primarily for use on low-volume roads, used steel beams can be utilized for a significant cost savings. In previous research for concept 2, an alternate shear connector (ASC) was developed and subjected to static loading. In this investigation, the ASC was subjected to cyclic loading in both pushout specimens and composite beam tests. Based on these tests, the fatigue strength of the ASC was determined to be significantly greater than that required in typical low volume road single span bridges. Based upon the construction and service load testing, the steel-beam precast unit bridge was successfully shown to be a viable low volume road bridge alternative. The construction process utilized standard methods resulting in a simple system that can be completed with a limited staff. Results from the service load tests indicated adequate strength for all legal loads. An inspection of the bridge one year after its construction revealed no change in the bridge's performance. Each of the systems previously described are relatively easy to construct. Use of the ASC rather than the welded studs significantly simplified the work, equipment, and materials required to develop composite action between the steel beams and the concrete deck.
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Most research current to the time of these projects was focused on use of Superpave mix designs on higher volume roads. Low volume roads have different requirements in terms of mix design, aggregate types, aggregate sources and project budgets. The purpose of this research was to determine if the Superpave mix design strategy for low volume roads was practical and economical. Eight projects were selected in five counties. The projects were completed in the summer of 1998. Performance evaluation of the resulting pavements was carried out annually. There was no significant increase in costs related to the use of Superpave. Nor were there any significant construction issues. There were some differences noted in placement and compaction in the field, but these were not serious.
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A 59-year-old kidney recipient was diagnosed with a late onset of severe chronic inflammatory demyelinating polyradiculoneuropathy and almost fully recovered after stopping tacrolimus and one course of intravenous immunoglobulin treatment. Unique features of this patient are the unusually long time lapse between initiation of tacrolimus and the adverse effect (10 years), a strong causality link and several arguments pointing toward an inflammatory etiology. When facing new neurological signs and symptoms in graft recipients, it is important to bear in mind the possibility of a drug-induced adverse event. Discontinuation of the suspect drug and immunomodulation are useful treatment options.
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Patients with Alzheimer's disease (AD) and schizophrenia display cognitive, behavioural disturbances and morphological abnormalities. Although these latter reflect progressive neurodegeneration in AD, their significance in schizophrenia is still unclear. We explored the patterns of hippocampal and amygdalar atrophy in those patients and their associations with clinical parameters. Structural magnetic resonance imaging was performed in 20 elderly schizophrenia patients, 20 AD and 19 healthy older controls. Hippocampal and amygdalar volumes were obtained by manual segmentation with a standardized protocol and compared among groups. In both schizophrenia and AD patients, left hippocampal and amygdalar volumes were significantly smaller. The hippocampus/amygdala ratio was significantly lower in schizophrenia compared to both AD cases [2.4 bilaterally, 95% C.I. 2.2 to 2.7] and healthy controls bilaterally [2.5, 95% C.I. 2.3 to 2.9 in left and 2.7, 95% C.I. 2.4 to 3.1 in right hemisphere]. In schizophrenia patients, a significant positive correlation was found between age at disease onset and the right hippocampus/amygdala volume ratio (Spearman rho=0.56). Negative symptoms correlated with higher right/left amygdala volume ratio (Spearman's rho=0.43). Our data show that unlike AD, the hippocampus/amygdala ratio is abnormally low and correlates with the age at onset in schizophrenia, being a neurodevelopmental signature of the disease.
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The multiscale finite-volume (MSFV) method has been derived to efficiently solve large problems with spatially varying coefficients. The fine-scale problem is subdivided into local problems that can be solved separately and are coupled by a global problem. This algorithm, in consequence, shares some characteristics with two-level domain decomposition (DD) methods. However, the MSFV algorithm is different in that it incorporates a flux reconstruction step, which delivers a fine-scale mass conservative flux field without the need for iterating. This is achieved by the use of two overlapping coarse grids. The recently introduced correction function allows for a consistent handling of source terms, which makes the MSFV method a flexible algorithm that is applicable to a wide spectrum of problems. It is demonstrated that the MSFV operator, used to compute an approximate pressure solution, can be equivalently constructed by writing the Schur complement with a tangential approximation of a single-cell overlapping grid and incorporation of appropriate coarse-scale mass-balance equations.
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Chronic kidney disease (CKD), impairment of kidney function, is a serious public health problem, and the assessment of genetic factors influencing kidney function has substantial clinical relevance. Here, we report a meta-analysis of genome-wide association studies for kidney function-related traits, including 71,149 east Asian individuals from 18 studies in 11 population-, hospital- or family-based cohorts, conducted as part of the Asian Genetic Epidemiology Network (AGEN). Our meta-analysis identified 17 loci newly associated with kidney function-related traits, including the concentrations of blood urea nitrogen, uric acid and serum creatinine and estimated glomerular filtration rate based on serum creatinine levels (eGFRcrea) (P < 5.0 × 10(-8)). We further examined these loci with in silico replication in individuals of European ancestry from the KidneyGen, CKDGen and GUGC consortia, including a combined total of ∼110,347 individuals. We identify pleiotropic associations among these loci with kidney function-related traits and risk of CKD. These findings provide new insights into the genetics of kidney function.