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Stéphanie Badiou

Publications and source records attributed to Stéphanie Badiou.

8 recordsLinked to original sources
PubMed2006

Association of aminothiols with the clinical outcome in hemodialysis patients: comparison of chromatography and immunoassay for homocysteine determination.

BACKGROUND: Controversial results on hyperhomocysteinemia and cardiovascular risk in hemodialysis (HD) could be due in part to the methodology used for homocysteine (Hcy) determination. OBJECTIVE: The aim of this study was to compare the influence of the method used for Hcy determination (chromatography or immunoassay) with regard to the association of Hcy with cardiovascular mortality rate in HD patients in a 3-year prospective study. METHODS: A total of 162 patients undergoing HD were included in a cohort study. Baseline Hcy levels were measured by HPLC and fluorescence polarization immunoassay (FPIA). Cysteine and cysteinylglycine were determined simultaneously with Hcy measurement by HPLC. RESULTS: Hcy levels obtained with both methods were highly correlated (r(2)=0.927, p<0.0001). An increased relative risk (RR) for cardiovascular mortality (n=31) was found between the highest against lowest tertile of Hcy for both HPLC (RR 2.74, 95% CI 1.07-7.02; p<0.05) and FPIA (RR 2.76, 95% CI 0.99-7.70; p=0.05). Interestingly, increased cysteine (> or =452 micromol/L) and cysteinylglycine (> or =36.6 micromol/L) levels were associated with a decreased RR of non-cardiovascular death (n=26) (RR 0.27, 95% CI 0.09-0.79; p=0.02) for cysteine and (RR 0.28, 95% CI 0.09-0.90; p=0.03) for cysteinylglycine when compared to the first tertile. CONCLUSIONS: This study demonstrated an increased risk of cardiovascular mortality in HD patients with Hcy values in the third tertile, independent of the method used. HPLC offers the advantage of simultaneous determination of other aminothiols that appear to be associated with non-cardiovascular mortality.

Adult↗
PubMed2006

Protein inhibitor of neuronal nitric oxide synthase (PIN) is a new regulator of glucose-induced insulin secretion.

We previously showed that pancreatic beta-cells express neuronal nitric oxide synthase (nNOS) that controls insulin secretion through two catalytic activities: nitric oxide (NO) production and cytochrome c reductase activity. We now provide evidence that the endogenous protein inhibitor of nNOS (PIN) is expressed in rat pancreatic islets and INS-1 cells. Double-immunofluorescence studies showed a colocalization of PIN with both nNOS and myosin Va in insulin-secreting beta-cells. Electron microscopy studies confirmed that PIN is mainly associated with insulin secretory granules and colocated with nNOS in the latter. In addition, PIN overexpression in INS-1 cells enhanced glucose-induced insulin secretion, which is only partly reversed by addition of an NO donor, sodium nitroprusside (SNP), and unaffected by the inhibitor of cytochrome c reductase activity, miconazole. In contrast, the pharmacological inhibitor of nNOS, Nomega-nitro-l-arginine methyl ester, amplified glucose-induced insulin secretion, an effect insensitive to SNP but completely normalized by the addition of miconazole. Thus, PIN insulinotropic effect could be related to its colocalization with the actin-based molecular motor myosin Va and as such be implicated in the physiological regulation of glucose-induced insulin secretion at the level of the exocytotic machinery.

Animals↗
PubMed2005

Is tenofovir involved in hypophosphatemia and decrease of tubular phosphate reabsorption in HIV-positive adults?

OBJECTIVES: Tubulopathy with hypophosphatemia have been observed in HIV-positive patients receiving a tenofovir-containing regimen. However, the real incidence and prevalence of hypophosphatemia and their relation to tubular reabsorption disorders in tenofovir-treated patients remain uncertain. The aim of our study was to explore the effect of tenofovir on phosphatemia and on tubular phosphate reabsorption. METHODS: In a first transversal study, 145 HIV-positive adults (44+/-9 years) receiving tenofovir 300 mg daily with a mean exposure of 11+/-9 months were included. In a second prospective study, 29 HIV-positive antiretroviral experienced adults (44+/-10 years) were evaluated before introduction of tenofovir 300 mg daily (M0) and at 3 months (M3) and 6 months (M6), thereafter. Phosphate, creatinine, glucose and protein levels were determined in plasma and urine. The ratio of maximal reabsorption capacity (TmPO4)/glomerular filtration rate (GFR) was determined by using the normogramm of Walton and Bijvoet. RESULTS: In the transversal study, 26% of patients had hypophosphatemia (<0.84 mmol/l) while 47% of patients had a decreased TmPO4/GFR (<0.8 mmol/l). In the prospective study, baseline prevalence of hypophosphatemia (<0.84 mmol/l) and decreased TmPO4/GFR (<0.8mmol/l) was 31 and 41%, respectively. Three and 6 months after starting tenofovir, there is no significant change in mean phosphate levels (M0:0.91 mmol/l, M3:0.97 mmol/l, M6:0.98 mmol/l) and mean TmPO4/GFR (M0:0.80 mmol/l, M3:0.88 mmol/l, M6:0.84 mmol/l). Moreover, prevalence of hypophosphatemia (M3:28%, M6:28%) and decreased TmPO4/GFR (M3:41%, M6:45%) remained stable. CONCLUSION: Hypophosphatemia linked to a decreased proximal tubular reabsorption was frequently observed in HIV-positive adults independently of the use of tenofovir. In this preliminary study, no worsening effect on phosphatemia and tubular phosphate reabsorption was observed 6 months after introduction of tenofovir in treatment experienced patients.

Adenine↗
PubMed2005

A patient with neurological symptoms and abnormal leukotriene metabolism: a new defect in leukotriene biosynthesis.

A 15-year-old male patient presented with mental retardation, mild motor impairment, and partial deafness. Biochemical investigations showed an abnormal urinary profile of leukotrienes. Concentration of leukotriene D(4) (LTD(4)), which is usually not detectable, was highly increased, whereas LTE(4), the major urinary metabolite in humans, was completely absent. These data suggest membrane-bound dipeptidase deficiency, a new defect in leukotriene biosynthesis on the step of LTE(4) synthesis, as underlying defect.

Adolescent↗
PubMed2005

Elevated plasma cysteinylglycine levels caused by cilastatin-associated antibiotic treatment.

Imipenem (thienamycin formamidine), a broad-spectrum beta-lactam antibiotic, is always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin might cause an accumulation of the aminothiol cysteinylglycine. We demonstrate here that when patients are treated with imipenem-cilastatin, their plasma levels of cysteinylglycine are significantly and specifically increased, while cysteine levels are decreased and homocysteine levels are unaffected. We conclude that antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized.

Anti-Bacterial Agents↗
PubMed2005

Evaluation of the ABX Pentra 400: a newly available clinical chemistry analyser.

The performance of the ABX Pentra 400, a new multiparametric analyser available for routine and specialised clinical chemistry analyses, was evaluated according to the National Committee for Clinical Laboratory Standards (NCCLS) and Valtec protocols. Substrate concentrations and enzyme activities were determined by spectrophotometric measurement after coloured reaction or UV detection-based reactions; electrolyte concentrations were determined with ion-selective electrodes, and specific protein concentrations were assayed by immunoturbidimetry. In total, 32 of the most common clinical chemistry parameters were evaluated under simulated routine conditions. The analytical performance of the system and the quality of the ABX Pentra reagent line were both examined in a single-site study. The ABX Pentra 400 was compared with the Olympus AU640, Konelab-Konepro, Beckman Coulter-Immage and Beckman Coulter-Access 2, depending on the tests available on these analysers. The coefficient of variation (CV) values were within expected values. Coefficients of correlation showed high correlation between the analysers compared. The influence of interfering substances was moderate. The practicability of the system was good. We conclude that good reliability and practicability make the ABX Pentra 400 system suitable for laboratories with various needs.

Bilirubin↗
PubMed2003

Immunoturbidimetric determination of C-reactive protein (CRP) and high-sensitivity CRP on heparin plasma. Comparison with serum determination.

Determination of C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP), markers of systemic inflammation and atherosclerosis risk, usually requires serum samples, while heparin plasma samples are routinely collected for routine chemistry. This study evaluates the use of heparin plasma samples for hs-CRP and CRP determinations using immunoturbidimetric methods on an Olympus system. As a result, analytical performance, including linearity, imprecision values, and determination from 185 clinical samples, are not affected by the type of sampling, validating the use of heparin plasma samples for CRP and hs-CRP determination with Olympus reagents.

Blood Chemical Analysis↗