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Biomedical subjects

P Chauveau

Publications and source records attributed to P Chauveau.

At least 19 recordsLinked to original sources
PubMed1996

Long-term folic acid (but not pyridoxine) supplementation lowers elevated plasma homocysteine level in chronic renal failure.

Moderate hyperhomocysteinemia, a risk factor for premature atherosclerosis, is present in chronic uremic patients. We prospectively evaluated the effects of sequential supplementation with pyridoxine (70 mg/day) and folic acid (10 mg/day) for two 3-month periods in 37 nondialyzed patients (29 males) with creatinine clearance (CCr) ranging from 10 to 80 ml/min, whose plasma vitamin B12 and folate level was in the normal range. Mean (+/- SD) baseline plasma total homocysteine (Hcy) was 14.9 +/- 5.2, 16.5 +/- 5.1 and 26.1 +/- 12.1 mumol/l (upper limit in 45 healthy controls 14.1 mumol/l) in patients with CCr 40-80, 20-40 and < 20 ml/min, respectively. Following pyridoxine Hcy did not significantly decrease whereas following folic acid Hcy decreased significantly to 9.9 +/- 2.9 (-33% vs. baseline), 10.3 +/- 3.4 (-37%) and 15.4 +/- 5.5 (-40%), respectively (Student's paired t test, p < 0.001) in the 3 groups. We conclude that folate (but not pyridoxine) pharmacologic supplementation is effective in lowering elevated plasma Hcy in chronic renal failure patients, thus suggesting that enhancing the Hcy remethylation pathway may overcome hyperhomocysteinemia in such patients. In view of the potential atherogenic effects of hyperhomocysteinemia, long-term folate supplementation should be considered in uremic patients.

Adult↗
PubMed1995

Role of metformin accumulation in metformin-associated lactic acidosis.

OBJECTIVE: To investigate the role of metformin accumulation in the pathophysiology of metformin-associated lactic acidosis. RESEARCH DESIGN AND METHODS: We used high-performance liquid chromatography to measure plasma metformin concentrations in 14 patients who experienced lactic acidosis (pH < 7.35 and lactate concentration 5 > mmol/l) while receiving chronic metformin treatment. Their treatment was generally based on alkalinization and dialysis therapy. RESULTS: Clinical shock and/or evidence of tissue hypoxia was found in all patients with the exception of one who had a nonsteroidal anti-inflammatory drug-induced anuria. Ten patients had significant metformin accumulation (plasma metformin concentrations 4.1-84.9 mg/l, normal value 0.6 +/- 0.5 mg/l before drug intake), generally because of failure to withdraw metformin despite intercurrent pathological conditions affecting its renal elimination (serum creatinine concentrations ranging from 269 to 1,091 mumol/l). There was no metformin accumulation (plasma metformin 0.03-0.7 mg/l) in the four other patients, who had less severe renal failure (serum creatinine 140-349 mumol/l). The severity of the patient's general condition did not predict early hospital mortality (death before discharge from the intensive care unit) even in patients in shock. Whereas it was high in those without metformin accumulation (only 1 of 4 patients recovered), early hospital mortality was low in the 10 patients with metformin accumulation and was not related to its extent (3 patients died with end-stage hepatic failure or cardiac failure). Correlation studies showed a positive correlation between serum creatinine and plasma metformin and between plasma metformin and arterial lactate but, for the latter correlation, only in patients with metformin accumulation. CONCLUSION: Metformin-associated lactic acidosis is not necessarily due to metformin accumulation; true type B (aerobic) lactic acidosis, i.e., without an apparent associated hypoxic factor, seems exceptional. Neither the severity of the clinical picture nor the degree of metformin accumulation predicted survival; rather, the prognosis was dependent upon the severity of the associated pathological conditions.

Acidosis, Lactic↗
PubMed1995

Hepatitis C virus (HCV) infection in haemodialysed patients: HCV-RNA and anti-HCV antibodies (third-generation assays).

Samples from 128 haemodialysed patients were tested by anti-HCV 2nd- and 3rd-generation assays from Ortho: 53 were positive by ELISA 2.0 and 54 (42%) by ELISA 3.0. The 54 anti-HCV-positive patients were tested by RIBA-2 and RIBA-3 and by PCR for the detection of HCV-RNA: 46 of the 47 patients (98%) reactive by RIBA-2 and 48 of the 51 patients (94%) reactive by RIBA-3 were HCV-RNA positive. Three patients with RIBA-3 indeterminate results were HCV-RNA negative. Among the 74 anti-HCV negative patients, 29 were tested by PCR with negative results. Two distinct episodes of hepatitis C have been observed in two patients during the follow-up and 44 of the 50 patients (88%) known positive for anti-HCV since at least 1989 were still viraemic in 1993. A very high correlation was found between anti-HCV antibodies reactive by RIBA and the presence of HCV-RNA. A lack of protection after a resolved infection and a high frequency of chronic disease have been observed as well as a reinfection or a reactivation of the infection in two patients.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Molecular analysis of 53 fragile X families with the probe StB12.3.

Fifty-three pedigrees with the fragile X syndrome have been studied for amplification of the CGG repeat sequence adjacent to the CpG island in the FMR1 gene. Probe StB12.3 allowed direct detection of affected males, carrier females, normal transmitting males, as well as prenatal diagnosis. Comparison of our molecular data with our previous linkage data from 38 families indicates the effectiveness of direct DNA analysis. A total of 325 individuals were studied and no new mutation was found. All daughters of males with a premutation had a premutation. When the mother had a full mutation no children had a premutation. In premutated mothers, the size of the premutation seems to be a determining factor for the transition to the full mutation. All affected males had a full mutation or mosaicism and only 42% of the females with a full mutation were mentally impaired. Analysis of large families over 3 generations illustrated clearly the Sherman paradox. Furthermore, the analysis of these families is in reasonable agreement with the multiallelic model of Morton and Macpherson [Proc Natl Acad Sci USA 89:4215-4217, 1992]. Mosaic cases in the offspring of the mothers with a full mutation suggest a maternal germinal mosaicism. Then an abnormal methylation and a somatic heterogeneity established in very early steps of embryogenesis could explain these cases.

Alleles↗
PubMed1994

[Recombinant vaccine and extracting vaccine against hepatitis B in patients with kidney insufficiency: comparative immunogenicity].

OBJECTIVES: Patients with chronic renal failure respond rather poorly to hepatitis B vaccines. A better response could be expected from recombinant vaccines including both the S and the pre-S2 antigens. We therefore prospectively compared the immunogenicity of plasma-derived Hevac B vaccine (H) with that of recombinant GenHevac B vaccine (G). METHODS: Vaccinations were performed in 120 non-dialyzed patients with chronic renal failure. The patients were randomly divided into two groups. Group G included 60 patients (24 males, mean age 58 +/- 16 years, mean creatinine clearance 25.3 +/- 12.6 ml/min) who were given the Hevac B vaccine at the dose of 5 micrograms. Group H included 60 patients (31 males, mean age 60 +/- 15 years, mean creatinine clearance 24.4 +/- 11.1 ml/min) who were given GenHevac B vaccine at the dose of 20 micrograms. All vaccinations were repeated at 0, 1, 2, 4 and 12 months. RESULTS: Following the fourth injection, seroconversion (anti-Hbs > or = 2 mlU/ml) was observed in 50/59 (85%) of the patients in group G versus 38/58 (67%) in group H (p < 0.02). Seroprotection (> or = 10 mlU/ml) was obtained in 42/59 (71%) vs 34/58 (59%), (NS) in the two groups respectively with a geometric mean titer of 112 versus 229 mlU/ml (NS) in responders. Following the booster injection at the 12th month, seroconversion was achieved in 48/51 (94%) vs 40/53 (76%) (p < 0.01) and seroprotection in 84% vs 70% (p = 0.053) respectively. The mean geometric titers were 879 and 1001 mlU/ml. CONCLUSIONS: Recombinant GenHevac B vaccine elicits seroconversion and seroprotection in a higher proportion of patients with chronic renal failure than the plasma-derived Hevac B vaccine, with comparably high antibody titers in responders. Therefore, GenHevac B vaccine should be recommended for vaccinating patients with chronic renal failure against hepatitis B.

Adult↗
PubMed1994

Immunogenicity of the recombinant GenHevac B Pasteur vaccine against hepatitis B in chronic uremic patients.

Immunogenicity of the recombinant GenHevac B vaccine (G), containing both the S and the preS2 antigen, was compared with that of the plasma-derived Hevac B (H) vaccine in 120 chronic uremic predialysis patients. Sixty received 20 micrograms/dose of G and 60 received 5 micrograms/dose of H at 0, 1, 2, 4, and 12 months. Two months after the fourth injection, seroconversion (antibody to hepatitis B surface antigen [HBs], > or = 2 mIU/mL) was seen in 85% of group G and 67% of group H patients (P < .02); seroprotection (anti-HBs, > or = 10 mIU/mL) was seen in 71% and 59%, respectively. The geometric mean titers (GMT) of anti-HBs in responders were 112 and 229 mIU/mL, respectively. After booster injection at month 12, seroconversion occurred in 94% and 76% and seroprotection in 84% and 70%, with anti-HBs GMTs of 879 and 1001 mIU/mL in groups G and H, respectively. The recombinant GenHevac B vaccine elicited seroconversion and seroprotection in a higher proportion of chronic uremic patients, with comparably high anti-HBs antibody titers in responders.

Adult↗
PubMed1993

Effects of blood pressure and antihypertensive treatment on progression of advanced chronic renal failure.

The potential role of blood pressure and antihypertensive treatment on the progression of advanced chronic renal failure was analyzed in 223 adult patients (126 males) with well-defined primary chronic renal diseases (glomerulonephritis, n = 73; angionephrosclerosis, n = 24; interstitial nephritis, n = 61; polycystic kidney disease, n = 52, Alport's syndrome, n = 13). Effect of average mean arterial pressure (MAP) obtained during follow-up, antihypertensive treatment (normotensive, conventional antihypertensive treatment, angiotensin-converting enzyme inhibitors [ACEI]), gender, type of the nephropathy, age, body mass index, and protein intake were analyzed using a multivariate analysis of variance. Mean arterial pressure was significantly and independently correlated with duration (r = -0.40, P < 0.0001) and slope of creatinine clearance (delta Ccr; r = 0.32, P < 0.0001). Mean arterial pressure and antihypertensive treatment could predict 25% of the variation in duration. Gender, type of the nephropathy, and MAP were able to predict 30% of the variation in delta Ccr. When analyzing results by type of nephropathy, MAP was significantly and inversely correlated with duration in glomerulonephritis (r = 0.29, P < 0.05), and positively with delta Ccr in angionephrosclerosis and interstitial nephritis (r = 0.49, P < 0.05 and r = 0.36, P < 0.01, respectively). In each type of nephropathy, conventional antihypertensive treatment and ACEI had grossly similar effects upon duration and slope except. In conclusion, blood pressure level is an important contributor to progression of chronic renal failure but its effect was more evident in angionephrosclerosis and interstitial nephritis at the extreme values of blood pressure distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Correlation between hepatitis C virus (HVC) RNA and anti-HVC antibodies in a hemodialysis population].

Polymerase chain reaction (PCR) was applied to detect HCV-RNA in 75 hemodialyzed patients. Anti-HCV status was determined by ELISA-2 and by RIBA-2 for reactive samples by ELISA. ALT levels were monthly determined during the year preceding the end of the study. For 60 patients, anti-HCV serology was known since 1989 and 39 of them were tested for the presence of HCV-RNA at least four times during the 2 preceding years. The 9 patients who were negative for anti-HCV antibodies were negative by PCR. Of the 7 patients with an indeterminate profile by RIBA-2, 3 were positive by PCR: 1/1 with C-33c band only and 2/6 with C22-3 band only. Of the 59 patients reactive by RlBA-2, 57 were HCV-RNA positive. Of the 2 HCV-RNA negative patients, one had been PCR positive before interferon therapy. Of the 38 patients without acute hepatitis tested by PCR on 5 successive samples, all the specimens of 11 and 23 patients were HCV-RNA negative and HCV-RNA positive respectively. In 4 patients, a transient viremia was observed. The group of HCV-RNA positive patients had mean ALT levels greater than those who were negative. A correlation was established between HCV infection and both the time on dialysis and the number of blood transfusions. A high concordance (97%) was observed between antibodies to HCV and HCV-RNA.

Adult↗
PubMed1993

Soluble CD23 as an effector of immune dysregulation in chronic uremia and dialysis.

Patients with chronic renal failure often present an immunodeficiency state paradoxically exacerbated by hemodialysis and associated with signs of T cell activation. The presence of circulating monokines suggests that monocytes are also activated. Whether or not this includes B cells is controversial, despite frequently abnormal antibody responses. We thus investigated whether the soluble low-affinity receptor for IgE (Fc epsilon RII/CD23), recently identified as a marker of B cell and monocyte activation and possibly involved in T cell activation, was modulated by chronic renal failure and hemodialysis. Relative to values in healthy individuals (N = 31), plasma concentrations of soluble CD23 were significantly elevated in non-dialyzed chronically uremic patients (N = 44), more elevated in patients on peritoneal dialysis (N = 24), and most elevated in those on regular hemodialysis (N = 132), stabilizing after about six months. Soluble CD23 levels were unmodified by the first dialysis session but rose markedly during regular dialysis with cellulose or polysulfone membranes, but not with polyacrilonitrile AN-69 membranes. Soluble CD23 levels correlated with levels of IgG, and those of tumor necrosis factor alpha and interleukin-6, suggesting that increased sCD23 levels reflect activation of B cells and monocytes, respectively. These findings reinforce the view of soluble CD23 as a multi-functional receptor/cytokine, and provide evidence that it might contribute to the immune dysregulation associated with chronic renal failure and exacerbated by hemodialysis.

Adolescent↗
PubMed1993

Antibodies to hepatitis C virus by second generation test in hemodialyzed patients.

To assess the prevalence and the incidence of hepatitis C virus (HCV) in a dialysis unit, we prospectively tested for anti-HCV in chronic hemodialysis patients and staff members since January 1989, using a first generation assay. Incidence was nil in staff and low in patients (3.7% in 89, 1% in 90), and prevalence was 30% in patients. In January 1991 blood samples from 115 patients were tested by first (EL1) and second generation (EL2) ELISA (Ortho Diagnostic System). Positive subjects were tested by a RIBA-2 confirmation test. Fifty-three patients were negative by all tests. Positive tests were observed in 62 patients (54%) including 36 positive in EL1 and EL2, and 26 only by EL2. All positive patients were reactive by RIBA-2 but nine were classified undetermined (only one positive band). In five patients reactivity of antibodies to 5-1-1 and C-100-3 gradually declined during the study. Second generation tests gave a better correlation with time on dialysis and blood transfusion. We conclude that second generation tests for HCV are more accurate for estimating true prevalence of HCV infection in hemodialysis units.

Adolescent↗
PubMed1993

Late referral to maintenance dialysis: detrimental consequences.

Thirty per cent of patients who started maintenance haemodialysis at our institution between January 1989 and December 1991 had been referred at a very late stage of their renal disease. To assess the causes and consequences of such late referral we retrospectively compared clinical and laboratory features of 65 patients who had been referred less than 1 month prior to first dialysis (late referral, or LR group) and of 153 patients who had been previously followed-up by us for more than 6 months (early referral, or ER group). Age, sex ratio, and socioeconomic status were similar in the two groups. In the LR group, 38 patients had never been referred to a nephrology unit, whereas 27 had discontinued nephrological surveillance. Fluid overload, severe hypertension, and/or pulmonary oedema was present in 57% of LR versus 15% of ER patients (P < 0.001). Mean (+/- 1 SD) systolic and diastolic blood pressure was greater in the LR than the ER group (173 +/- 19/99 +/- 12 versus 147 +/- 15/84 +/- 8 mmHg, P < 0.001). Mean plasma concentration of creatinine, urea and phosphate was significantly greater, whereas bicarbonate, calcium, haematocrit and albumin were less in the LR than the ER group. Most (88%) LR patients started dialysis in emergency conditions through central vein catheterization. Total hospital stay lasted 34.5 +/- 16.3 days in LR versus 5.8 +/- 3.0 days in ER patients (P < 0.0001), resulting in an excess cost of 0.2 million French francs per LR patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hyperhomocysteinemia, a risk factor for atherosclerosis in chronic uremic patients.

Hyperhomocysteinemia has been shown to constitute an independent risk factor for premature occlusive arterial disease (N Engl J Med 324:1149), a frequent complication in chronic uremic patients in whom homocysteine (Hcy) accumulation has been reported to occur. We prospectively determined fasting plasma level of total, protein-bound Hcy in 118 adult chronic uremic patients, either dialyzed or not. In 79 non-dialyzed patients (47 male) with various degrees of chronic renal failure (RF) assessed by creatinine clearance (CCr), none receiving folate, B6 or B12 vitamin supplementation, mean (+/- 1 SD) plasma Hcy level was 16.2 +/- 8.1 mumol/liter in 28 patients with mild RF (CCr 30 to 75 ml/min), 23.3 +/- 14.7 in 29 patients with moderate RF (CCr 10 to 29.9), and 29.5 +/- 14.4 in 22 patients with advanced RF (CCr < 10), a significant difference (P < 0.01 for all groups) compared to 45 healthy controls (8.2 +/- 2.2 mumol/liter). Linear regression analysis showed a significant correlation between plasma creatinine and Hcy concentrations (r = 0.49, P < 0.0001). Hcy was significantly higher in 20 patients (16 males) who had past histories of occlusive arterial disease than in the 59 (31 males) who did not (30.9 +/- 19.1 vs. 19.6 +/- 9.7 mumol/liter, P < 0.001) and all of the former had Hcy level > 14.1 mumol/liter (the upper limit in healthy controls) versus 35 of 59 in the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Factors affecting progression in advanced chronic renal failure.

In a series of 174 patients with advanced chronic renal failure due to well defined primary nephropathies, we retrospectively studied factors influencing the rate of progression of renal failure. Using multivariate analysis of variance, we examined the role of gender, type of nephropathy, body mass index, age, protein intake quantified from 24-hour urine urea excretion, blood pressure and need for antihypertensive treatment (including a group of patients treated with ACE inhibitors) on the rate of decline of creatinine clearance (Ccr). We found a prominent and independent influence of sex and type of nephropathy, and to a lesser extent of mean arterial pressure and protein intake. Overall, these covariates were significantly correlated with the slope of decline in creatinine clearance (n = 174; r = 0.61; r2 = 0.37; p < 0.001) indicating that nearly 40% of the total variation in the slope could be predicted by these covariates. The influence of blood pressure was more readily apparent in males, and in patients with the opposite extreme values, i.e., chronic tubulointerstitial nephritis (CIN) and hypertensive angionephrosclerosis (ANS). The effect of protein intake was marginal and limited to patients with CIN and chronic glomerulonephritis (CGN). Effect of gender was important with a progression nearly two times faster in males than in females, and was mostly apparent in polycystic kidney disease (PKD) and in CGN. Type of nephropathy was also determinant. The rate of progression was steeper in Alport's syndrome than in CGN and ANS, and in the latter than in PKD and CIN (slope: CIN = PKD < CGN = ANS < Alport).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Didanosine pharmacokinetics in patients with normal and impaired renal function: influence of hemodialysis.

The pharmacokinetics of didanosine were investigated following oral administration of a single 375-mg dose to eight human immunodeficiency virus-seropositive patients with normal renal function and eight human immunodeficiency virus-seropositive uremic patients. In uremic patients, the plasma half-life was longer than that in control patients (respectively, 4.5 +/- 2.2 and 1.6 +/- 0.4 h). The ratio of total plasma clearance to absolute bioavailability was four- to fivefold lower in uremic patients than in patients with normal renal function (respectively, 491 +/- 181 and 2,277 +/- 738 ml/min). Because of the decrease in elimination, concentrations in plasma were higher for uremic patients than for control patients; the maximum concentrations of drug in plasma were, respectively, 3,978 +/- 1,607 and 1,948 +/- 994 ng/ml; the areas under the concentration-time curve were, respectively, 14,050 +/- 4,262 and 3,000 +/- 956 ng.h/ml. Didanosine was removed by hemodialysis with an extraction ratio of 53% +/- 8%, a hemodialysis clearance value of 107 +/- 21 ml/min, and a fractional drug removal during a 4-h dialysis of 20% +/- 8% of the dose. Dosage adjustments are necessary in uremic patients.

Administration, Oral↗