[Vascular nephropathies].
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Biomedical subjects
Publications and source records attributed to Christian Jacquot.
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Recent recommendations emphasize the need to assess kidney function using creatinine-based predictive equations to optimize the care of patients with chronic kidney disease. The most widely used equations are the Cockcroft-Gault (CG) and the simplified Modification of Diet in Renal Disease (MDRD) formulas. However, they still need to be validated in large samples of subjects, including large non-U.S. cohorts. Renal clearance of (51)Cr-EDTA was compared with GFR estimated using either the CG equation or the MDRD formula in a cohort of 2095 adult Europeans (863 female and 1232 male; median age, 53.2 yr; median measured GFR, 59.8 ml/min per 1.73 m(2)). When the entire study population was considered, the CG and MDRD equations showed very limited bias. They overestimated measured GFR by 1.94 ml/min per 1.73 m(2) and underestimated it by 0.99 ml/min per 1.73 m(2), respectively. However, analysis of subgroups defined by age, gender, body mass index, and GFR level showed that the biases of the two formulas could be much larger in selected populations. Furthermore, analysis of the SD of the mean difference between estimated and measured GFR showed that both formulas lacked precision; the CG formula was less precise than the MDRD one in most cases. In the whole study population, the SD was 15.1 and 13.5 ml/min per 1.73 m(2) for the CG and MDRD formulas, respectively. Finally, 29.2 and 32.4% of subjects were misclassified when the CG and MDRD formulas were used to categorize subjects according to the Kidney Disease Outcomes Quality Initiative chronic kidney disease classification, respectively.
OBJECTIVE: To quantify the amount of potential prescription errors for anticancer drugs in order to improve the quality of care. SETTING: The cytotoxic reconstitution unit at the Laennec Hospital in Paris, France during 6 months in the year 2000. METHOD: Pharmacist carried out a systematic analysis (e.g. dose, protocol, physicochemical properties) of the prescriptions for anticancer drugs (ACDs) before the compounding and handling at the cytotoxic unit of the pharmacy took place. The detected errors and potential errors were documented and analysed. MAIN OUTCOME MEASURE: Numbers and kinds of medication errors. RESULTS: Documenting data was difficult because of the inadequacy of existing classifications that usually do not include potential errors in prescriptions for with ACDs. Despite the presence of a formulary on the clinical wards, 349 errors were detected and documented, mainly concerning pharmaceutical aspects. Physicians were not aware of this type of errors due to lack of studies about their impact. Teaching aids such as a computer program for prescribing and production of ACDs could help in minimising these errors. CONCLUSION: The 349 detected errors involved mainly the physicochemical properties of preparations. A computerised prescription network could possibly reduce the number of such errors. Furthermore, a redefinition of the classifications of errors for cytotoxic preparations seems desirable, and such classifications should include typical pharmaceutical problems, and potential errors that do not reach the patient.
BACKGROUND: The role of podocytes in human crescentic glomerulonephritis (GN) has been underestimated. This may be due to the confounding fact that "dysregulated" podocytes are able to proliferate, lose their markers, and acquire new epitopes. Moreover, in experimental anti-glomerular basement membrane (GBM) crescentic GN, podocytes participate in the crescent formation. The aim of this study was to investigate the involvement of podocytes in human immune crescentic GN. METHODS: Renal biopsies from 12 patients with anti-GBM disease and 14 with class IV lupus GN were studied by immunohistochemistry for the following markers: (1) synaptopodin, GLEPP1, podocalyxin, podocin, alpha-actinin-4, and vimentin for podocyte identification; (2) PCNA, Ki-67, and p57 for cell cycle assessment; (3) cytokeratins for identifying epithelial cells but not normal podocytes; (4) CD68 for tagging a macrophagic epitope; (5) alpha-smooth-muscle actin (alpha-SMA), a phenotypic marker of myofibroblasts. RESULTS: "True" (capsular) crescents lining Bowman's capsule and (tuft) "pseudocrescents" covering the glomerular tuft with a persistent patent urinary space were present in the 2 types of crescentic GN in similar percentages. Several features indicated that podocytes were involved in the formation of the both crescent types. Identifiable podocytes expressed proliferation markers. Podocyte cytoplasmic expansions and racket-like podocytes bridged between the tuft and Bowman's capsule. True and pseudocrescents contained labeled podocytes. In addition, podocytes located outside of the crescents had often lost their markers (dedifferentiation) and acquired new epitopes (cytokeratins and CD68). CONCLUSION: In human immune crescentic GN, podocytes undergo proliferation and dysregulation that are indicative of a podocytopathy. Podocytes contribute to crescent formation.
Analysis of the biologic effects of erythropoietin and pathophysiology of chronic kidney diseases (CKD) suggests that treatment with erythropoiesis-stimulating agents (ESA) could slow the progression of CKD. By decreasing hypoxia and oxidative stress, it could prevent the development of interstitial fibrosis and the destruction of tubular cells. It could have direct protective effects on tubular cells through its antiapoptotic properties. It could help maintain the integrity of the interstitial capillary network through its effects on endothelial cells. Thus, suggesting that correcting anemia with ESA could slow the progression of CKD is biologically plausible. In patients with CKD, three small prospective studies and a retrospective study have suggested that treatment with ESA may have protective effects. Post-hoc analysis of the Reduction in Endpoints in Noninsulin-dependent Diabetes Mellitus with the Angiotensin II Antagonist Losartan study has also shown that anemia was an independent risk factor for progression of nephropathy in patients with type 2 diabetes. In addition, a large clinical trial, which had to be stopped prematurely because of labeling change for subcutaneous administration of epoetin alfa, suggests that complete normalization of hemoglobin levels is safe in CKD patients not on dialysis and without severe cardiovascular disease. Thus, it seems reasonable to advocate starting a large randomized, prospective study to determine if normalization of hemoglobin concentration can effectively slow the progression of CKD.
Transdifferentiation is characterized by a loss of normal epitopes by differentiated cells, accompanied by the acquisition of new epitopes and new functions. Podocytes are differentiated epithelial cells that cover and adhere to the outer surface of the glomerular basement membrane (GBM). The podocyte/GBM complex contributes to the selective filter function of the glomerular tuft. We have shown that, in various human glomerulonephritides, "dysregulated" podocytes acquire the potential to proliferate and multiply, undergo profound morphologic changes, detach from the GBM, and show phenotypic changes indicative of transdifferentiation. In the course of these events they lose their original epitopes and acquire macrophagic markers.
We recently demonstrated that mice lacking the gene for substance P (neurokinin 1) receptors (NK1-/-) show improved cortical dialysate serotonin (5-HT) responses to paroxetine [J. Neurosci. 21 (2001) 8188]. To test for changes that may involve the 5-HT transporter (5-HTT) in these mutant mice, in vivo/in vitro studies were performed. Autoradiographic quantification of 5-HTT was performed: [3H]citalopram binding did not reveal any modification of 5-HT binding sites in the dorsal raphe nucleus (DRN) of wild-type NK1+/+ control and mutant NK1-/- mice. These results were further confirmed by 5-HTT mRNA quantification using competitive reverse transcription and polymerase chain reaction (RT-PCR) assay, which showed similar messenger levels in the DRN of both mice genotypes. The functional status of 5-HTT in vivo was tested by using the zero net flux method of quantitative microdialysis in two serotonergic nerve terminal regions, the frontal cortex and ventral hippocampus, of wild-type NK1+/+ and NK1-/- mice. Neither basal extracellular 5-HT levels nor the 5-HT extraction fraction of the probe (Ed an index of 5-HT uptake in vivo) differed between wild-type and mutant mice in the two brain regions studied. These results suggest that no compensatory response to the constitutive deletion of the tachykinin NK1 receptor involving changes in the activity of the selective 5-HT transporter occurred in the DRN, frontal cortex and ventral hippocampus in mice.
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The plasma concentrations of S-nitrosothiols, which are circulating nitric oxide metabolites with potential biologic activity, are increased among patients undergoing chronic hemodialysis (HD). However, the ability of S-nitrosothiols to release nitric oxide at physiologically relevant sites may be reduced among HD patients, because of impaired availability and/or activity of factors involved in S-nitrosothiol breakdown. The resultant lack of S-nitrosothiol bioavailability could contribute to the high cardiovascular risk for such patients. A possible relationship between plasma S-nitrosothiol levels and cardiac outcomes, as well as all-cause mortality rates, was investigated in a cohort of 250 chronic HD patients and who were undergoing regular dialysis three times per week were monitored for 1 yr. During that follow-up period, major cardiac events and all-cause deaths were prospectively recorded. At baseline, high plasma S-nitrosothiol levels (>2 micro M, corresponding to the top quartile of all measured values) were independently associated with pulse pressure in an adjusted multivariate analysis (odds ratio, 1.03; 95% confidence interval, 1.01 to 1.05; P = 0.007). During the follow-up period, 36 patients died (16 as a result of cardiac causes) and 33 patients experienced major adverse cardiac events. In an adjusted Cox proportional-hazards model, high plasma S-nitrosothiol concentrations (i.e., the top quartile versus the three other quartiles) were an independent predictor of cardiac events (hazard ratio, 3.30; 95% confidence interval, 1.61 to 6.76; P = 0.001) but not of all-cause death. Therefore, among chronic HD patients, markedly elevated plasma S-nitrosothiol levels are associated with pulse pressure and predict cardiovascular outcomes. These findings support the hypothesis that impaired S-nitrosothiol bioavailability in uremia is an important factor for the excessive cardiovascular risk among HD patients.
Peginterferon is now the gold standard of therapy in patients with chronic hepatitis C virus infection. Extrahepatic manifestations of HCV are usually treated with interferon alfa. Here we report on a patient with HCV-related cirrhosis and cryoglobulinaemia who presented with an acute and long-lasting exacerbation of vasculitis during treatment with peginterferon. To our knowledge this is the first report of an acute exacerbation of cryoglobulinaemia-related vasculitis involving skin, peripheral nerve and kidney in a patient treated with peginterferon for HCV-related cirrhosis. The long half-life of peginterferon might explain the long-lasting symptoms of vasculitis. Clinicians should be aware of possible sustained flare of cryoglobulinaemia-associated vasculitis in patients receiving peginterferon.
BACKGROUND: Cardiac disease is the main cause of mortality in long-term hemodialysis patients. Cardiac troponins (cTn) have been proposed to be markers of cardiac damage, but their value is still debated in hemodialysis patients. The aim of this prospective study is to assess the prognostic value of biochemical cardiac markers in long-term hemodialysis patients. METHODS: We measured serum levels of cTn I (cTnI), cTn T (cTnT), and creatine kinase-MB (CK-MB) in 258 asymptomatic patients (mean age, 60 +/- 15 years; 150 men) before the dialysis treatment. All causes of death and major adverse cardiac events (MACEs: cardiac death, myocardial infarction, or unstable angina) were recorded at 1 and 2 years of follow-up. A Cox proportional hazard regression model was used to identify factors predictive of mortality. RESULTS: On inclusion, 48 patients (18.6%) had cTnT levels greater than 0.1 ng/mL, 46 patients (17.8%) had cTnI levels greater than 0.15 ng/mL, and 18 patients (7.0%) had CK-MB levels greater than 3 ng/mL. Of 246 patients followed up at 2 years, 64 patients (26%) had died, including 29 patients (11.8%) of cardiac disease, and 49 patients (19.9%) experienced at least 1 MACE. MACEs were significantly greater for patients with elevated predialysis serum cTnT and CK-MB levels (>0.1 ng/mL and 3 ng/mL, respectively) than for patients with normal levels of these cardiac markers (31.9% versus 17.1%; P = 0.01; 38.9% versus 18.4%; P = 0.02, respectively). No differences were found for cTnI levels. In multivariate analysis, age (relative risk [RR], 1.04; P = 0.002), previous ischemic heart disease (RR, 2.5; P = 0.0001), and serum cTnT levels greater than 0.1 ng/mL (RR, 1.9; P = 0.04) were independent significant factors for MACEs. CONCLUSION: Increased predialysis serum levels of cTnT and CK-MB, but not cTnI, were predictive of a high risk for overall mortality and MACEs at 2 years in asymptomatic hemodialysis patients.
BACKGROUND: Among the cellular changes occurring in renal fibrosis, epithelial-mesenchymal cell transdifferentiation or transition (EMT) is a phenomenon characterized in epithelial cells by loss of epithelial markers and acquisition of mesenchymal phenotype and of fibrosing properties. METHODS: To test the hypothesis that EMT is involved in human pauci-immune crescentic glomerulonephritis (PICGN), we studied 17 renal biopsies from 11 PICGN patients for: (i) proliferating cell nuclear antigen (PCNA) and cell cycle inhibitors (cyclin-dependent kinase inhibitors) p27 and p57; (ii) cell lineage phenotype markers: podocalyxin, synaptopodin and GLEPP-1 for podocytes; CD68 for macrophagic epitope; CD3 for T lymphocytes; alpha-smooth muscle actin (alpha-SMA) for myofibroblasts; vimentin for mesenchymal cells; and cytokeratins (CKs) for parietal epithelial cells (PECs); (iii) glomerular fibrosis by labelling collagens I, III and IV, and heat-shock protein 47 (HSP47), a marker of collagen-synthesizing cells; and (iv) co-localization of alpha-SMA, CK and HSP47 using confocal laser microscopy. RESULTS: The crescent cells proliferated greatly. They did not express p27 and p57. Different cell lineage markers could be identified in crescents: the major component was made of 'dysregulated' PECs negative for CK, followed by PECs positive for CK, macrophagic cells and myofibroblasts. Furthermore, some cells co-expressed CK and alpha-SMA. This latter co-expression suggests a transitional phase in the dynamic phenomenon of EMT. Therefore, proliferative and dysregulated glomerular epithelial cells could be a possible cellular source of myofibroblasts via EMT. In addition, HSP47 labelled many crescent cells and frequently co-localized in CK-positive epithelial cells and in alpha-SMA-positive myofibroblasts, indicating that these cells were involved in glomerular accumulation of collagens. CONCLUSION: EMT is a transient cellular phenomenon present in glomeruli in human PICGN contributing to the formation of myofibroblasts from epithelial cells and to glomerular fibrosis.
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Familial juvenile hyperuricemic nephropathy (FJHN [MIM 162000]) is an autosomal-dominant disorder characterized by abnormal tubular handling of urate and late development of chronic interstitial nephritis leading to progressive renal failure. A locus for FJHN was previously identified on chromosome 16p12 close to the MCKD2 locus, which is responsible for a variety of autosomal-dominant medullary cystic kidney disease (MCKD2). UMOD, the gene encoding the Tamm-Horsfall/uromodulin protein, maps within the FJHN/MCKD2 critical region. Mutations in UMOD were recently reported in nine families with FJHN/MCKD2 disease. A mutation in UMOD has been identified in 11 FJHN families (10 missense and one in-frame deletion)-10 of which are novel-clustering in the highly conserved exon 4. The consequences of UMOD mutations on uromodulin expression were investigated in urine samples and renal biopsies from nine patients in four families. There was a markedly increased expression of uromodulin in a cluster of tubule profiles, suggesting an accumulation of the protein in tubular cells. Consistent with this observation, urinary excretion of wild-type uromodulin was significantly decreased. The latter findings were not observed in patients with FJHN without UMOD mutations. In conclusion, this study points to a mutation clustering in exon 4 of UMOD as a major genetic defect in FJHN. Mutations in UMOD may critically affect the function of uromodulin, resulting in abnormal accumulation within tubular cells and reduced urinary excretion.
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