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Biomedical subjects

L Potaux

Publications and source records attributed to L Potaux.

At least 19 recordsLinked to original sources

[In situ production of interferon gamma and interleukin 6 by infiltrating cells from human kidney allografts in irreversible rejection. Modulation by cytokines].

Using ELISPOT assays, we detected a significant number of cells secreting interferon-gamma and interleukin 6 among 8 irreversibly rejected kidney allografts compared with normal kidneys. Interleukin 2 increases the frequency of interferon-gamma producing cells and interleukin 4 decreases the frequency of both interferon-gamma and interleukin 6 producing cells.

Depression, Chemical

HILDA/LIF urinary excretion during acute kidney rejection.

Recently, a new lymphokine called HILDA (human interleukin for DA cells) has been described and cloned. This cytokine, initially described to be produced by alloreactive T lymphocyte clones grown from a rejected human kidney allograft, is identical to other factors termed D-factor, differentiation-inducing factor, differentiation inhibitory activity, hepatocyte-stimulating factor III, and leukemia inhibitory factor. HILDA/LIF induces various effects on neural, hemopoietic, embryonic cells as well as on bone remodeling and acute phase protein synthesis in hepatocyte. In this study we demonstrate the presence of HILDA/LIF in the urine but not in the serum of kidney graft recipients during acute rejection episodes, whereas this lymphokine was detectable neither in the serum nor in the urine of kidney transplanted patients with stable renal function. These data reinforce the notion of a possible role for this lymphokine in the inflammatory and/or the immune response.

Antibodies, Monoclonal

[Tumor necrosis factor in graft rejection. In situ hybridization study].

The development of necrosis and macrophage infiltration increases the risk of renal graft rejection. But the macrophages secrete the alpha form of the tumour necrosing factor (TNF) which is also involved in several immunologic and inflammatory phenomena. We therefore studied the expression of the gene TNF alpha by in situ hybridization during advanced stage rejection after renal transplantation: the grafts were infiltrated with macrophage-like cells expressing the mRNA of the TNF alpha gene, particularly deep in the cortex and in the medulla. These cells then secrete the TNF alpha molecule since they are recognized by anti-TNF alpha antibodies. These antibodies also recognize certain other glomerular endothelial and tubular epithelial cells which do not express the TNF alpha gene: these cells are undoubtedly the TNF target cells. These findings confirm the synthesis of TNF alpha in advanced stage renal graft rejection.

Colorectal Neoplasms

[Effect of verapamil on cyclosporine-induced vasoconstriction in human or murine isolated glomerules].

Cyclosporin is a very potent immunosuppressant, but it often produces renal disturbances which limit its clinical use. Using an image analyzer which determines the areas of isolated glomerules, we were able to demonstrate that cyclosporin in various concentrations exerts a direct vasoconstrictive effect on human and murine glomerules. We also showed that verapamil has an almost total inhibitory effect on cyclosporin-induced vasoconstriction. These findings seem to be of interest in clinical practice to reduce the nephrotoxicity of cyclosporin.

Animals

Decreased incidence of infection after renal transplantation with the use of cyclosporine.

The incidence of infection within six months of cadaveric kidney transplantation was reviewed in 183 consecutive patients. Prior to June, 1985, 91 patients received azathioprine 2 mg/kg/day and prednisone 0.5 mg/kg/day; 63 patients (group A1) also received antilymphocyte globulin 15 mg/kg/day for the first ten days, whereas for the 28 other patients (group A2) antilymphocyte globulin had to be withdrawn before 72 hours because of general intolerance. The next 92 patients received cyclosporine 5-8 mg/kg/day and prednisone 0.25 mg/kg/day (group B). The three groups were similar for all studied parameters except for the number of patients with anti-HLA antibodies. At six months the mortality rate was not significantly different between the three groups. After six months the number of infections per patient was 1.47, 1.03 and 0.84 (p less than 0.01) in groups A1, A2 and B respectively; the percentage of patients developing one or more infections was 81, 58 and 57% (p less than 0.01); bacterial infections: 57, 50 and 34% (p less than 0.01); viral infections: 40, 14 and 10% (p less than 0.01); cytomegalovirus infections: 27, 11 and 4% (p less than 0.001). After adjustment with logistic regression upon factors which might facilitate infections, the results showed a significantly lower incidence of infection for the cyclosporine-treated group, especially for cytomegalovirus, as compared with the antilymphocyte globulin-treated group.

Adolescent

Improvement of leucocytic Na+ K+ pump activity in uremic patients on low protein diet.

Leucocytic Na+ K+ pump activity was assessed in 20 patients with advanced renal failure. Na+ K(+)-ATPase activity was reduced when compared with the values obtained from normal subjects (101.8 +/- 48.6 versus 165.13 +/- 8.9 microM of Pi hr-1.g-1; P less than 0.001) and the mean 86Rb uptake by U 937 cells was depressed by 38% after the addition of patients' sera. Subsequently, patients were put on a diet providing 0.3 g protein/kg body weight daily and supplemented with ketoacids. After three months of dietary treatment Na+ K(+)-ATPase activity increased to 142 +/- 48.3 (P less than 0.01) and reached normal values at the sixth month (162.8 +/- 54.70 microM of Pi hr-1.g-1; P less than 0.001) whereas 86Rb uptake increased by 23 percent when compared to initial values. These data suggest that among the different mechanisms which have been advanced to explain the defects in the Na+ pump observed in uremic patients, circulating inhibitors deriving from alimentary protein intake may affect cation transport.

Adult

Detection of vascular complications in renal allografts with color Doppler flow imaging.

One hundred ninety-five color Doppler flow (CDF) examinations were performed in 146 renal allografts to assess the capabilities of this technique in detecting intra- or extrarenal vascular complications. Conventional angiography was also performed in 44 transplants. In the group of transplants with angiographic correlation, CDF sonography enabled correct identification of 30 of 34 vascular complications. CDF showed 10 of 11 significant stenoses of the renal artery or of one of its main branches. There were two false-positive renal artery stenoses (one normal artery and one 40% stenosis). Nine of nine renal artery thromboses and the single pseudoaneurysm were also identified. Within the parenchyma, CDF sonography demonstrated five of five segmental infarcts, two of two postbiopsy arteriovenous fistulas, and three of six segmental or interlobar artery stenoses. Measurement of peak systolic velocity showed a significant difference (P less than .05) between a group (n = 8) with significant stenosis of the renal artery or one of its main branches (mean, 215.2 cm/sec +/- 32) and a group (n = 14) without stenosis (mean, 99.2 cm/sec +/- 19).

Adult

Hemodialysis grafts: color Doppler flow imaging correlated with digital subtraction angiography and functional status.

Twenty-two patients with hemodialysis grafts were prospectively evaluated with color Doppler flow imaging and digital subtraction angiography (DSA). Eighteen patients had normal functional parameters during hemodialysis, and four had increased venous pressure during hemodialysis. Color Doppler flow imaging allowed identification of nine macroaneurysms related to wall degeneration, two cases of spontaneous fistula formation between the graft and peripheral veins, and 20 stenoses. Use of color Doppler flow imaging led to overestimation of the degree of stenosis at the venous anastomosis when compared with use of angiography. Three cases of subclavian venous stenosis were identified only at angiography. Color Doppler flow imaging appears accurate in the detection of stenoses and seems sufficient for follow-up of normally functioning grafts. However, because of its low sensitivity for identification of proximal stenoses and the necessity of obtaining an angiogram to plan surgical or percutaneous correction, DSA remains the technique of choice.

Angiography, Digital Subtraction

Low-protein, low-phosphorus diet and tissue insulin sensitivity in insulin-dependent diabetic patients with chronic renal failure.

Tissue insulin sensitivity was measured by the glucose clamp technique in 8 uremic insulin-dependent diabetic patients before and after 3 months on a low-protein diet (LPD) providing daily 35 kcal/kg body weight, 60% of the caloric supply being obtained from carbohydrates. An improvement in tissue insulin sensitivity was observed for each steady state of the clamp and daily insulin requirements decreased significantly from 38.3 +/- 3.2 to 28.2 +/- 2.5 units (p less than 0.01) in spite of an increased carbohydrate intake. It is suggested that LPD lowers the production and accumulation of uremic toxins interfering with insulin sensitivity.

Adult

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