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G St-Louis

Publications and source records attributed to G St-Louis.

34 records · Page 2Linked to original sources
PubMed1988

NMR monitoring of the energy status of skeletal muscle during hemodialysis using acetate.

The concentration of phosphate-containing metabolites in the resting gastrocnemius muscle of three patients in chronic renal insufficiency was monitored by NMR spectroscopy before and during their regular hemodialysis using a conventional acetate bath. During dialysis, the muscle ATP concentration did not change, and no significant pyrophosphate accumulation was seen. The intracellular and extracellular inorganic phosphate concentration fell as expected. It is concluded that the rapid metabolism of acetate induced by dialysis does not affect the concentration of high energy phosphate-metabolites in the resting muscle of acetate-tolerant patients.

Acetates↗
PubMed1988

Efficacy of incorporating cyclosporine into liposomes to reduce its nephrotoxicity.

A preparation of cyclosporine (CsA) in liposomes was tested in the rat to evaluate its effectiveness in reducing CsA nephrotoxicity. The drug was injected intravenously in unilaterally nephrectomized Lewis rats at a daily dose of 25 mg/kg for 14 days, either in a cremophore solution (eight rats) or in a preparation of liposomes (eight rats). Another group of four animals received the cremophore solution alone. Overall, rats treated with the CsA-liposome preparation had reduced toxicity, exhibiting better survival rates and less weight loss than those treated with the CsA-cremophore. Incorporating CsA into liposomes induced a statistically significant (p less than 0.05) reduction in the otherwise progressive increase of serum creatinine during week 2 of the experiment. Following administration of CsA-liposome preparation, epithelial cells of the proximal renal tubules appeared morphologically normal, without evidence of vacuolization, which is characteristic of CsA nephrotoxicity and was seen in the CsA-cremophore group. Although the exact mechanism is not clearly understood, it is likely that the tissue distribution of CsA, when incorporated into liposomes, is modified in favour of the reticuloendothelial cells, thereby sparing highly sensitive, but non-target organs such as the kidneys.

Animals↗
PubMed1988

Adverse effect of blood transfusions on patient survival after resection of rectal cancer.

Studies have shown that the number of units of blood transfused perioperatively in patients operated on for colonic cancer has a progressively strong negative influence on survival. The present study, involving 198 patients with rectal cancer, was done to determine if perioperative blood transfusions had any prognostic significance. Multivariate regression analysis was applied to these patients, operated for cure of Dukes' stage A, B or C disease. Other variables analysed were age, sex, preoperative hemoglobin, albumin and lymphocyte values and the timing of transfusion. Perioperative deaths, pre- and post-operative immunodepression, neoplasia in situ, nonresections and stage D disease were excluded. It was found that the number of units of blood transfused perioperatively had a negative effect on patient survival, that was independent of the other analysed variables. It is suggested that blood transfusion perioperatively exerts an immunosuppressive effect on patients with rectal cancer.

Female↗
PubMed1987

Acetate metabolism and bicarbonate generation during hemodialysis: 10 years of observation.

The capacity of chronically hemodialyzed patients to metabolize acetate during conventional hemodialysis was evaluated using a retrospective study in 219 patients dialyzed for up to ten years under similar dialysis conditions. For each patient, and using all available data, a regression line relating the changes of plasma total CO2 during dialysis as a function of the pre-dialysis value was calculated. The intercept of this function indicates the plasma concentration where the losses of bicarbonate in the dialysate is matched by the generation of bicarbonate arising from the metabolism of acetate. This value therefore represents an individual index of the capacity of each patient to metabolize acetate. A value for this index smaller than 18.0 mM was considered abnormal. It was shown that around 10% of chronically hemodialyzed patients are clearly unable to metabolize acetate optimally. This defect is not related to the duration of dialysis, body weight or quality of hemodialysis treatments but is strongly related to sex, 19 of the 22 "acetate intolerant" patients being women. In a prospective study, all the 60 patients of the same population undergoing active dialysis were studied, and this index identified 12 abnormal (11 women, 1 man) patients and 48 normal patients. Plasma acetate measured at the end their dialysis treatments were significantly higher in abnormal than in normal patients. It is concluded: that this index is useful to identify the patients unable to metabolize acetate optimally; that only around 10% of hemodialyzed patients present a severe problem when dialyzed against acetate and should be dialyzed against bicarbonate; that dialysis against acetate does not fully correct the metabolic acidosis even in "normal" patients.

Acetates↗
PubMed1987

Hemolytic uremic syndrome in renal allografted patients treated with cyclosporin.

The classical triad of hemolytic uremic syndrome (microangiopathic hemolytic anemia, severe thrombopenia, and renal failure) developed de novo in three of our renal transplanted patients under cyclosporin A treatment. The predominant morphologic findings in the grafts consisted of glomerular and arteriolar thrombosis as well as arteriolonecrosis, all features of the syndrome. In one instance, ischemic bowel disease supervened after graft removal and was associated with persistent low grade microangiopathic process. De novo hemolytic uremic syndrome has been reported in patients treated with cyclosporin A following bone marrow or liver transplantation as well as in a few renal graft recipients. This peculiar form of cyclosporin A nephrotoxicity should not be confused with acute rejection of the renal transplant.

Adult↗
PubMed1986

Blood transfusions and survival after colectomy for colorectal cancer.

This study was carried out to determine the effect of perioperative blood transfusions on the survival of patients operated on for colorectal cancers. Cox's regression analysis was applied to 281 patients operated for cure of Dukes' stage A, B or C disease. Other variables studied were age, sex, tumour location, and preoperative hemoglobin, lymphocyte and albumin values. Perioperative deaths, pre- and postoperative immunodepression, neoplasia in situ, nonresections and stage D disease were excluded. It was found that the number of units of blood transfused had a strong influence on the prognosis of patients with colorectal cancer, particularly colonic cancers, but the effect could not be demonstrated when rectal cancers were studied separately, perhaps because of the small number of cases. The mechanism of action of blood transfusions seems to be independent of the other analysed variables. The authors suggest that perioperative blood transfusions may have an immunomodulatory effect in patients with colonic cancer, as already shown in recipients of transfused kidney allografts.

Aged↗
PubMed1986

The acid-base status does not influence the rate of acetate metabolism in hemodialyzed patients.

The present study was undertaken to evaluate whether the acid-base status influences the rate of acetate metabolism in patients chronically hemodialyzed against acetate. Ten patients (5 "intolerant" and 5 "tolerant" to acetate) received in a randomized order and for three consecutive dialyses each of the six following infusions in the venous line of the dialyzer: NaHCO3 (22, 44 or 88 mEq/h), NaCl (22 or 44 mEq/h) or Dextrose 5% in water (30 mmol/h). Plasma acetate was measured at the end of the dialysis. Bicarbonate infusions increased significantly blood pH and plasma bicarbonate but did not change the plasma acetate concentration at the end of dialysis. We conclude that the rate of acetate metabolism is not modified by changes in the acid-base status within the range usually observed in hemodialyzed patients. A significant hypoxemia per dialysis was noted only in AT patients with lower plasma acetate and rapid acetate metabolism. We conclude that acetate metabolism (and not plasma acetate concentration) plays a significant role in dialysis-induced hypoxemia.

Acetates↗
PubMed1983

Beneficial effects of methylprednisolone on urinary excretion of lysosomal enzymes in acute renal ischemia.

An experimental model of canine normothermic renal ischemia was used to determine whether lysosomal urinary enzyme excretion reflects the extent of ischemic cellular injury, as assessed by subsequent renal function (serum creatinine level) and morphologic changes. The value of a lysosomal membrane-stabilizing agent (methylprednisolone) in protecting kidneys from ischemic damage by preventing lysosomal enzyme release was assessed. Results showed conclusively that urinary enzyme activities of beta-galactosidase and N-acetyl-beta-glucosaminidase are valuable indicators of renal cellular damage and functional outcome after ischemic injury, and that methylprednisolone at a dose of 30 mg/kg, given intravenously 1 hour before a 1-hour period of normothermic ischemia, protects the kidney both biologically and morphologically, by reducing the excretion of lysosomal enzymes after revascularization.

Acetylglucosaminidase↗
PubMed1977

Gentamicin pharmacokinetics during hemodialysis in patients suffering from chronic renal failure.

Because the elimination of gentamicin, a potent aminoglycoside antibiotic, is dependent almost entirely on renal excretion, renal functional impairment drastically changes the pharmacokinetics of this drug. As a first step in the study of the effects of renal insufficiency and the anephric state on the pharmacokinetic parameters of gentamicin, serum and urine levels of this drug were studied after a single intravenous bolus dose during hemodialysis in patients suffering from chronic renal failure. The data were fitted to the two-compartment open model and the appropriate kinetic parameters were calculated with the COMPT computer program modified by Pfeffer. The rate constant of metabolism was estimated from plasma and dialysis rate constants of elimination. The rate of renal excretion was shown to be very weak in patients who were not anuric. The use of the mathematical equations of the two-compartment open model demonstrated that, after a single dose of gentamicin, the percentage of decrease of serum concentration with time does not represent, because of tissue binding retention, the percentage of drug eliminated from the body. It was shown that pharmacokinetic parameters represent a useful tool in the optimization of gentamicin therapy.

Adult↗
PubMedDate not supplied

[Renal transplantations: current reality and future challenges].

Kidney transplantation is a well recognized form of treatment for end-stage renal failure patients. Transplanted patients can hope for a prolonged and productive life. Many factors are responsible for the improvement of kidney transplantation over the last years. Despite its progress and success, many limitations still exist: shortage of kidney, humoral hypersensitivity or recipients, side effects of immunosuppressive medication and chronic rejection. Will the induction of specific tolerance to xenograft, with the help of transgenic biology, be the solution of tomorrow?

Forecasting↗