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Biomedical subjects

L Potaux

Publications and source records attributed to L Potaux.

At least 73 records · Page 4Linked to original sources

Effect of ponsinomycin on cyclosporin pharmacokinetics.

The influence of treatment with ponsinomycin, a new macrolide antibiotic, on the pharmacokinetics of cyclosporin A has been studied in 10 renal transplant patients. The pharmacokinetics of cyclosporin A was investigated at steady state, before and during treatment with ponsinomycin. On average, the blood levels of cyclosporin A were doubled by the macrolide, possibly due to a decrease in elimination or/and to an increase in absorption. Ponsinomycin should be use very carefully in patients treated with cyclosporin A.

Adult↗

[Demonstration of direct vasoconstrictive effect of cyclosporin on glomeruli isolated from human kidney].

Cyclosporin (CsA), a potent immunosuppressive agent, can induce severe renal damage, characterized by lesions in the tubulo interstitial region and decreased renal function. Isolated glomeruli can be considered as a fruitful model to evidence the direct effect of drugs at the level of glomerular structures. The present study aims to evidence, in this model, vasoactive response of isolated human renal glomeruli induced by different CsA concentrations. Area changes of such isolated glomeruli can be assessed by a semi-automatic morphometric method, using a video-camera device coupled with a microprocessor (Biocom 2000). Experiments are done under double bind conditions. CsA-induced decrease in glomeruli area is dose- and time-dependent. CsA effect is rapid in that glomerular area is significantly decreased even after 5 min. incubation; vasoconstrictive effect is more important (and maximum) after 10 min. incubation; significant decrease can be noted with 10(-7) M (-11.41%) and 10(-6) M (-10.26%). In conclusion, the isolated glomerulus model allows us to demonstrate the direct vasoconstrictive effect of CsA, that can in part explain the renal functional changes and the acute renal failure often described in human clinic.

Analysis of Variance↗

Multiple myeloma and AL amyloidosis in a renal transplant recipient.

Seven years after a cadaver kidney transplantation a 33-year-old man presented with a monoclonal gammopathy secondarily complicated by AL amyloidosis mainly expressed as a sicca syndrome, gammopathy that ultimately developed into multiple myeloma. The mechanisms responsible for the occurrence of monoclonal gammopathy in renal transplant recipients are discussed.

Adult↗

Effect of a ketoacid diet on glucose tolerance and tissue insulin sensitivity.

Effects of a low protein (0.3 g/kg/day) diet on glucose tolerance and tissue insulin sensitivity were studied in 25 non-diabetic and eight insulin-dependent diabetic uremic patients before and three months after dietary treatment. Carbohydrates accounted for 65% of the caloric intake in the first group and 57% in the second. In the first group, a 50 g oral glucose tolerance test showed that after three months blood glucose was significantly reduced at T60 (P less than 0.05) and serum insulin at T0, T30 (P less than 0.05) and T60 (P less than 0.02). Ten patients of the first group underwent an euglycemic, hyperinsulinemic clamp study; the tissue sensitivity to insulin index of all three clamp periods improved (P less than 0.01 for the first and second, P less than 0.02 for the third). Five patients in the second group underwent a euglycemic clamp study; glucose metabolism increased with each clamp period. Concomitantly, their daily insulin requirements decreased from 37.2 +/- 3.1 to 24.8 +/- 2.7 U/day (P less than 0.05). This conspicuous improvement observed in both groups might be related to a decrease in uremic toxin(s) derived from protein intake. Beneficial results on atherosclerosis and cardiovascular pathology may occur from the reduction of hyperinsulinism.

Adult↗

[Castleman's disease and glomerular nephropathy (apropos of 1 case].

We report a case of Castleman's disease of multifocal plasma-cell type revealed by a severe general weakness, associated to a nephrotic syndrome with renal failure. The characteristic aspects of lymphoid hyperplasia with hyalinization of follicles and interfollicular vascular proliferation were observed in mesenteric lymph nodes, the spleen was involved by an infarcted localisation of Castleman's disease. The glomerular lesions were consistent with a proliferative mesangial glomerulonephritis. The removal of the spleen and of the mesenteric nodes involved by the disease, associated with a steroid course was curative. The nephrotic syndrome appears to be etiologically related to the presence of the Castleman's tumor. The removal of the tumor relieves the proteinuria and the renal failure as in other cases reported in the literature.

Acute Kidney Injury↗

Effect of a low-protein diet on chemiluminescence production by leukocytes from uremic patients.

Chemiluminescence (CL) emission from leukocytes was studied in 20 uremic patients after ingestion of opsonized zymosan. CL production was impaired when compared with control groups. Six months after a low-protein, low-phosphorus diet supplemented with essential amino acids and ketoanalogues (SD) was started, a significant improvement in CL production was observed. SD may be expected to decrease the susceptibility of uremic patients to bacterial infections.

Adult↗

Effect of a low-protein diet on urinary albumin excretion in uremic patients.

Fifteen patients with advanced renal failure (creatinine clearance less than 25 ml/mn) and with severe albuminuria (greater than 1.5 g/24 h) were put on a low-protein (0.3 g/kg body weight), low-phosphorus (5-7 mg/kg body weight) diet supplemented with essential amino acids and ketoanalogues. During the 6-month follow-up, urinary albumin excretion and fractional renal albumin clearance were reduced significantly while serum albumin concentration increased; no nutritional change occurred during the study.

Adult↗

Pharmacokinetics of intravenous and intraperitoneal fosfomycin in continuous ambulatory peritoneal dialysis.

Kinetics of fosfomycin were investigated in six patients undergoing continuous ambulatory peritoneal dialysis. Each subject received both an i.v. and an i.p. 1 g dose of fosfomycin with a one week washout between doses. Fosfomycin was assayed by a microbiological diffusion technique. After intravenous injection the fosfomycin serum kinetic parameters were as followed: elimination half-life (t1/2 beta) 38.4 +/- 8.7 h; volume of distribution 0.32 +/- 0.02 l/kg; total plasma clearance 7.0 +/- 1.4 ml/min and peritoneal clearance 3.2 +/- 0.2 ml/min. Dialyzate fosfomycin concentrations reached a maximum mean value of 32.2 +/- 2.8 micrograms/ml at 4 h post-injection and fosfomycin was detectable in dialyzate samples for up to 72 hours post-dosing. After intraperitoneal instillation, fosfomycin appeared in the serum rapidly and the mean peak plasma concentration was 36.2 +/- 2.8 micrograms/ml at the 4th h. The absorption rate (ka) was 0.580 +/- 0.039 h-1 and the absorption of fosfomycin from peritoneal space was 68.4 +/- 6.0%. These data suggest a bidirectional exchange through the peritoneal membrane. Intraperitoneal administration of 1 g either 48 h apart for anephric patients or 36 h apart for patients with residual renal function may achieve therapeutic serum concentrations.

Female↗

Low protein and low phosphorus diet in patients with chronic renal failure: influence on glucose tolerance and tissue insulin sensitivity.

Ten patients with advanced renal failure (glomerular filtration rate 25 mL/min) were treated with a low phosphorus and low protein diet supplemented with ketoacid analogues. Before starting the diet and four months afterwards, a 50 g oral glucose tolerance test with a three step euglycemic insulin clamp was carried out. A dose-response curve of total body insulin sensitivity was plotted. By the fourth month, glucose tolerance had improved with significantly lower T0, T30, and T60 insulin levels. These results are attributed to the improvement in insulin action as demonstrated by the clamp technique. The dose-response curve had a distinctly higher plateau after dietary treatment, and the tissue sensitivity index to insulin (M/l ratio) was significantly improved. It is suggested that treatment of uremic patients with a low protein diet may reduce levels of a putative insulin inhibitor.

Adult↗