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Biomedical subjects

J Chanard

Publications and source records attributed to J Chanard.

At least 19 recordsLinked to original sources
PubMed1995

[Access of the abdominal cavity for treatment by continuous peritoneal dialysis].

Anatomical and functional characteristics of the peritoneal cavity have to be evaluated prior to catheter implantation for continuous ambulatory peritoneal dialysis (CAPD). This review summarizes the constraints that may be encountered and the few technical certitudes that have been validated. The American Registry for CAPD is the unique source of validated data, indicating that the early risk for peritonitis following catheter implantation is significantly lessened with a two-cuff catheter used by a surgeon. Catheter shape as well as per-operative antibiotic prophylaxy have no effect on prognosis.

Catheterization↗
PubMed1994

Randomised controlled trial of enalapril and beta blockers in non-diabetic chronic renal failure.

OBJECTIVE: To compare the ability of angiotensin converting enzyme inhibitors and beta blockers to slow the development of end stage renal failure in non-diabetic patients with chronic renal failure. DESIGN: Open randomised multicentre trial with three year follow up. SETTING: Outpatient departments of six French hospitals. PATIENTS: 100 hypertensive patients with chronic renal failure (initial serum creatinine 200-400 mumol/l. 52 randomised to enalapril and 48 to beta blockers (conventional treatment). INTERVENTIONS: Enalapril or beta blocker was combined with frusemide and, if necessary, a calcium blocker or centrally acting drug in patients whose diastolic pressure remained above 90 mm Hg. RESULTS: 17 patients receiving conventional treatment and 10 receiving enalapril developed end stage renal failure. The cumulative renal survival rate was significantly better in the enalapril group than in the conventional group (P < 0.05). The slope of the reciprocal serum creatinine concentration was steeper in the conventionally treated patients (-6.89 x 10(-5)l/mumol/month) than in the enalapril group (-4.17 x 10(-5)l/mumol/month; P < 0.05). No difference in blood pressure was found between groups. CONCLUSION: In hypertensive patients with chronic renal failure enalapril slows progression towards end stage renal failure compared with beta blockers. This effect was probably not mediated through controlling blood pressure.

Acebutolol↗
PubMed1994

Cuprophane but not synthetic membrane induces increases in serum tumor necrosis factor-alpha levels during hemodialysis.

Cytokine synthesis and secretion by blood mononuclear cells is a well-documented phenomenon in hemodialyzed patients. The present study was conducted in 17 chronically hemodialyzed patients to test the relative effect of uremic toxicity, membrane biocompatibility, dialysate composition, and the risk of endotoxinemia on the serum level of tumor necrosis factor-alpha (TNF-alpha). The only significant parameter that influenced circulating TNF-alpha was the chemical characteristics of the dialyzer membrane. Tumor necrosis factor-alpha levels significantly increased during the session with cuprophane, whereas they decreased with AN69. The TNF-alpha increase was documented whatever the dialysate buffer and the presence or absence (negative Limulus amoebocyte lysate test) of endotoxin in the dialysate. In the subgroup of patients treated with a contaminated dialysate and AN69, none had clinical symptoms and the central body temperature remained constant throughout the session. In these patients, serum TNF-alpha levels did not change after priming the dialyzer with sterile saline. In conclusion, the serum TNF-alpha level during hemodialysis appears to be modulated by biocompatibility, permeability, and binding properties of dialysis membrane rather than dialysate composition. Endotoxin in the dialysate did not result in positive TNF-alpha balance no matter what its possible priming effect on mononucleated blood cells.

Acrylic Resins↗
PubMed1994

Antihypertensive effect of amlodipine and lack of interference with cyclosporine metabolism in renal transplant recipients.

The catabolism of various calcium channel blockers through cytochrome P-450 is heterogeneous and may be modified by concomitant use of cyclosporin A. In an open study we investigated the antihypertensive effect and clinical tolerance of the dihydropyridine amlodipine and its effects on cyclosporine kinetics in stable hypertensive renal transplant recipients not taking corticosteroids. Ten adult hypertensive patients grafted for 21.4 +/- 8.9 months and well stabilized with normal renal function were included in the study. Renal artery stenosis was ruled out by normal Doppler echography. After 2 weeks of placebo, amlodipine was started at a daily dose of 5 mg. The dose was then adjusted to 10 mg if necessary. Blood and urine chemistries and whole-blood cyclosporine trough levels were measured weekly. Cyclosporine kinetics were determined on a hourly basis before amlodipine administration and after 4 weeks of treatment. Normal blood pressure was obtained with the use of 5 mg/d amlodipine in 7 patients and 10 mg/d in 3, diastolic blood pressure decreasing from 98.7 +/- 3.8 to 81.3 +/- 9.1 mm Hg (P = .0007). Heart rate slightly increased by 10% (P < .02). The drug was well tolerated, and only minor ankle edema was found in 3 patients. Cyclosporine doses were not modified and cyclosporine levels remained unchanged throughout the study. Cyclosporine kinetic parameters were not significantly different at the beginning and end of the study. Bioequivalence was demonstrated indicating that cyclosporine biotransformation was not altered by the concomitant administration of amlodipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Value of renal scintigraphy in the diagnosis of vascular complications of renal transplantation].

Nuclear medicine can make an efficient contribution to the diagnosis and monitoring of renal disease and to the assessment of therapeutic interventions in the field of renal transplantation. The new radio pharmaceutical MAG 3 labelled with 99mTc provides renal imaging of quality in patients with impaired renal function and enables quantitative evaluation of renal function. We report on radionuclide evaluation, with special emphasis on the analysis of the vascular component of the scintigram, in the different clinical situations (i.e. renal failure) that may compromise the outcome of a successful renal transplant.

Acute Kidney Injury↗
PubMed1994

[Evaluation of the frequency of acute renal insufficiency and therapeutic modalities in the nephrological milieu].

Due to lack of structured epidemiological studies, the incidence of acute renal failure (ARF) cannot be established in France. An empirical approach method based on answered questionnaire sent by mail to nephrology centers affiliated or not to universities has been used to estimate the frequency of ARF requiring dialysis in 1991. We postulated that the French population was homogeneously distributed among the different regions and that the response rate of 74% could be extrapolated to 100%. We could therefore calculate an incidence of 64 ARF per million of inhabitants. However, this underestimates the exact incidence since the accurate evaluation of IRA in a controlled region (Champagne-Ardenne) is 104 per million of inhabitants. In addition, this study underlines the fact that many ARF are not treated in nephrology units, especially those associated with multiorgan failure requiring slow continuous hemofiltration and hemodialysis. It is suggested that the establishment of a national Registry for ARF and an adequate training of nephrologists are prerequisites to assess epidemiology and the global cost of ARF.

Acute Kidney Injury↗
PubMed1993

Variations of protein C in uremic hemodialysed patients.

Protein C has been measured by three different assays (antigenic, amidolytic and chronometric) in 27 end-stage renal insufficient patients before and after hemodialysis. Protein C levels have been compared with other coagulation inhibitors (antithrombin III, protein S) and fibrinolytic parameters. Baseline anticoagulant activity of protein C has been found impaired in eight cases whereas other inhibitors were normal. In four cases, both anticoagulant and antigenic levels were low. In one case, amidolytic method could also found a low activity. Hemodialysis leads to an increase of protein C activity and antigen level. Heparinemia after hemodialysis does not interfere with the chronometric measurement of protein C anticoagulant activity. Total protein level, hematocrit, protein S and antithrombin III are also elevated after hemodialysis. Baseline fibrinolytic parameters are normal and remain unchanged after hemodialysis. The clinical relevance of such modifications is discussed.

Adult↗
PubMed1993

Failure of acyclovir to prevent cytomegalovirus infection in renal allograft recipients.

Cytomegalovirus (CMV) is the most common opportunistic pathogen following renal transplantation and remains a major concern in transplantation centers owing to its high morbidity and impact on renal allografts. Pending more effective antiviral drugs, efforts have been directed toward prevention strategies. We conducted a retrospective analysis to evaluate the efficacy of various prophylactic options used at our institution during the period April 1986 to August 1990. All CMV-negative patients with CMV-negative kidneys (D-R-) received screened, CMV-negative blood products (n = 19). CMV-specific immunoglobulins (CMV Ig) were used in 6 patients at increased risk for primary CMV infection and acyclovir was administered to 21 patients at an initial intravenous dose of 5 mg/kg body weight; then oral doses of 800-3200 mg per day were given according to the patients' estimated creatinine clearance. Thirty-two patients did not receive any CMV prophylactic treatment and served as controls. CMV monitoring of the patients during the first 6 months after transplantation showed an overall infection and disease rate of 81% and 38.1%, respectively, in the acyclovir-treated group. Compared with controls, the incidences of infection and disease were higher in the acyclovir-treated patients, with a significant difference for CMV infection (P = 0.002, generalized Wilcoxon test). Only 1 of the 19 D-R- patients presented with CMV infection. CMV Ig-treated patients tended to have less severe disease without any apparent reduction in infection incidence. Given the high rate of infection in patients at risk, we infer that high-dose acyclovir does not prevent CMV infection in our setting of renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acyclovir↗
PubMed1993

Beta 2-microglobulin metabolism in uremic patients who are undergoing dialysis.

Plasma beta 2-microglobulin (beta 2m) is increased in chronically hemodialyzed patients and remains in a steady range once residual diuresis has stopped. Factors controlling such a steady state are unknown. We undertook metabolic studies to define whether plasma beta 2m is regulated by extrarenal proteolysis of the protein or by storage in a captation pool, a condition which may precede beta 2m-derived amyloidogenesis. Seventeen uremic patients on supportive therapy and five healthy controls were enrolled into the 6 to 10 day study. Using trace amounts of 131I-beta 2m and total body counting, half-life was between 2.4 and 8 days. 125I-beta 2m plasma kinetics was more suitable to calculate fractional catabolic rate and synthetic rate. A three compartment model was chosen to calculate turnover parameters in dialysis patients, whereas the regular two compartment model fitted best for healthy controls. beta 2m synthesis rate was increased in uremic patients when compared with controls (4.49 +/- 2.60 vs. 3.68 +/- 1.43 mg/kg/day, NS). The three compartment model did not integrate all the experimental data, since it was possible to calculate a captation compartment which accumulated beta 2m without fast proteolysis. The captation pool was positively correlated with plasma beta 2m concentration and comprised between 23% and 59% of the amount of the beta 2m disappearing from plasma per day. In conclusion, metabolic studies with radioiodinated beta 2m indicate a slight increase in beta 2m synthesis rate in uremic patients on supportive therapy, irrespective of the technique in use. Kinetic analysis requires a model taking into account a storage compartment which is more complex than the three compartment model.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1992

[Synthesis of collagen in culture of endothelial cells of the human umbilical vein. Effects of cyclosporine A].

Interstitial renal fibrosis and gingival hypertrophy are frequent side-effects of cyclosporin A which have been attributed to a dysfunction of extracellular matrix synthesis. Endothelial cells might participate in the matrix accumulation observed. We studied the effects of increasing concentrations of cyclosporin A on protein synthesis by human umbilical vein endothelial cells. Collagen synthesis decreased significantly to 800 ng/ml in both medium and cell layer. The percentage of hydroxylation of its proline residues decreased significantly as from 400 ng/ml. The main proteins, analysed by SDS-PAGE, were thrombospondin, fibronectin and the alpha 1 and alpha 2 chains of type IV collagen. These fractions did not show any change after 24 hours exposure to 200 ng/ml of cyclosporin A. These results demonstrate an inhibitory effect of cyclosporin A on collagen synthesis by human umbilical vein endothelial cells. Consequently, matrix accumulation by increased collagen synthesis in cyclosporin A treated patient may not be directly related to the drug effect on endothelial cells.

Collagen↗
PubMed1992

Kinetics of 125I-beta 2-microglobulin turnover in dialyzed patients.

The kinetics of beta 2-microglobulin (beta 2m) were studied in 17 anephric or functionally anephric hemodialyzed patients and five healthy subjects as controls. Highly purified beta 2m was radiolabeled with 125I and infused into patients. The radioactivity in plasma and dialysis fluids was measured during a week including two or three dialysis sessions. Patients were classified in four groups according to treatment: hemodialysis on Cuprophan (N = 5) or on AN69 membranes (N = 5), hemofiltration (N = 4) and CAPD (N = 3). Plasma activity was fitted to a three compartment model. In controls almost 100% of the radioactivity was recovered in urine within 96 hours and there was no extrarenal catabolism. In patients the fractional catabolic rate ranged from 0.0008 to 0.0022 min-1 versus 0.026 to 0.047 min-1 in controls. The synthetic rate was within the range of values from controls in 10 patients but higher in the seven others. It was correlated with plasma beta 2m concentration. Kinetic data indicate a retention of intact beta 2m. The original model was therefore modified with an additional compartment representing beta 2m captation. The amount of capted beta 2m was more elevated in hemodialyzed patients than in patients treated by hemofiltration or CAPD, in whom it could reach 5 mg/kg/day. Hemofiltration or CAPD may eliminate about 30 to 100% of beta 2m produced and therefore contribute to the low captation amount of these patients, as compared with that of patients treated by hemodialysis.

Adult↗