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Biomedical subjects

G Deray

Publications and source records attributed to G Deray.

At least 217 records · Page 12Linked to original sources
PubMed1985

Recent advances on endogenous Na+,K+-ATPase inhibitors: clinical investigation and purification.

Evidence exists which demonstrates the relationship between a Natriuretic Factor or Na+,K+-ATPase inhibitor and volemic expansion, both in man and animal. Patients having extracellular volume expansion have been studied for the effect of their plasma on erythrocytes 3H-ouabain binding. High levels of ouabain-like activity was found in plasma from acromegalic patients and patients with chronic renal failure. High levels were also observed in some hypertensive patients. A partial purification of such a compound was performed from urine of hypertensives. The partially purified compound inhibited to a greater extent the Na+,K+-ATPase semi-purified from dog kidney than that from sheep brain. The present data are consistent with the possible regulation of the activity or the secretion of plasma ouabain-like activity by extracellular volume.

Acromegaly↗
PubMed1985

[Circulating inhibitor of sodium active transport in essential hypertension and volemic expansion].

Circulating inhibitors of the Na+ pump have been proposed as participating in sodium excretion, extracellular and vascular volume regulation and as hypertensiogenic agents. The presence of digitalis-like compounds in human plasma has been investigated by measuring its ability to compete with tritiated ouabain for binding to the digitalis site of red blood cells. Their activities in plasma from either hypertensive or volume expanded patients were compared. High levels were found in plasma from 37 p. cent of the untreated patients with essential hypertension, 64 p. cent of patients with end-stage renal failure and 71 p cent of acromegalic patients in the hypersecreting phase. The patients of these two last classes have been selected as being normotensives and without family history of hypertension. An increased activity of the inhibitor should more likely be linked to the positive Na+ balance and the volemic expansion which characterise these last two diseases than to high blood pressure. The observations that the activity of the inhibitor is correlated with the plasma volume in acromegalic patients, it returns to normal values after hemodialysis in renal insufficiency or successful therapy of acromegaly and the decrease in its activity is proportional to the weight lost during dialysis in uremic patients, agree with this proposal.

Adult↗
PubMed1985

Plasma ouabain-like properties in hypertension and volume expansion.

The presence in human plasma of compounds able to interact with the sodium pump has been investigated. The effects of whole and deproteinized plasma on the parameters of ouabain binding to the digitalis sites of the sodium pump were compared. Changes in the apparent affinity were potentialized by deproteinization. High levels of ouabain-like activity were observed to be present not only in some hypertensive patients but also in normotensive patients with chronic renal failure and active acromegaly, indicating a probable relationship with positive sodium balance and volemic expansion.

Acromegaly↗
PubMed1984

[Circulating inhibitor of the Na+-K+ pump in essential hypertension. Physiological and pharmacological variations].

The presence of a circulating Na+ pump inhibitor has been assessed in 112 subjects by studying the effects of deproteinized plasma on ouabain binding to erythrocytes and/or inhibition of Na+-K+-ATPase activity. High levels of an inhibitor possessing some digitalis-like properties, were associated with essential hypertension, hypertensive heredity, treatment of hypertension with beta-blocking agents and high sodium intake. Low levels were found in hypertensives on diuretics, patients with chronic renal failure and normotensive controls. These observations are consistent with a possible role of this circulating inhibitor in the control of sodium balance and in hypertension.

Animals↗
PubMed1984

Investigation of the endogenous Na+-pump inhibitor in essential hypertension and blood volume expansion.

The digitalis-like activities of plasma extracts from 108 patients and normal subjects were measured by their ability to compete with ouabain for binding to the digitalis sites of the Na+-pump. High levels were found in 18 of 54 untreated patients with moderate hypertension, 10 of 14 patients with end-stage renal failure and six patients with active acromegaly. These levels returned to control values after dialysis in the patients with renal insufficiency and high levels of the inhibitor, and after successful surgery and cobalt therapy in seven acromegalic patients. An increase in circulating Na+, K+-ATPase inhibitor was also found in rats after chronic sodium loading. These results indicate that levels of the circulating compound with digitalis-like properties do not result from high blood pressure but, rather, are related to blood volume and Na+ balance.

Acromegaly↗
PubMed1984

[Essential arterial hypertension, cellular intolerance to sodium].

Much experimental and clinical evidence points to the fact that increased intracellular Na+ concentration could play an important pathogenic role in hypertension, especially where cells of excitable tissues are concerned. Active extrusion of Na+ (from the cells to the extracellular space) depends mainly on the activity of the system of membrane transport known as the Na+ pump. The extrusion of Na+ occurs in exchange for K+ and the activity of the pump depends on the enzyme Na+-K+-ATPase. The Na+ pump is inhibited by cardiotonic glycosides such as digitalis and ouabain . The results obtained in our laboratory suggest that the activity of the Na+ pump is controlled by an endogenic system acting in a similar manner to ouabain and digitalis. Experimental and clinical studies show: -- that the administration of Na+ increases the inhibitor effect both in urine and plasma; -- that the inhibitor is increased in about 50 p. 100 of patients with essential hypertension; -- that this increase seems to depend on familial or genetic factors. The biochemical identification of this endogenic inhibitor is now under way; it has a small molecular weight (less than 3000), is thermostable and anionic. This factor could have both a regulating role on Na+ turnover and a pathological role in hypertension. Its activity comes into competition cations also capable of inhibiting the Na+ pump, including K+.

Animals↗
PubMed1984

[Cutaneous lymphangioma. Value of the scanner. Pathogenic hypothesis and therapeutic implications].

The authors report the case of a 10-year-old child with a cutaneous lesion of the thigh present since birth and made up of small translucid raised areas grouped in clumps. The association with these pseudo-vesicles of erysipelatous exacerbations 3 or 4 times a year and the discharge of clear fluid indicative of lymphorrhoea led to a clinical diagnosis of complicated cutaneous lymphangioma. CT scan of the thigh showed absence of spread to deeper layers. This case serves as a basis for discussion of the pathogenic hypothesis of Whimster suggesting that the superficial vesicles are connected to larger lymphatic chambers in the subcutaneous tissue and that the course depends upon pressure variations within these chambers. If this were the case, surgical excision of these lymphatic chambers would be a logical alternative to symptomatic medical treatment of inflammatory episodes.

Child↗
PubMedDate not supplied

Hemolytic and uremic syndrome after heart transplantation.

Two cases of hemolytic and uremic syndrome in heart transplant recipients are reported. Among solid organ transplantations, this complication mainly occurred in renal transplantation and only 1 case was reported in heart transplantation in the literature. Cyclosporine was the only etiologic factor found. The renal outcome was severe with end-stage renal failure and no recovery of the renal function despite stopping cyclosporine, corticoids and plasma exchange.

Adult↗
PubMedDate not supplied

Neurotoxicity of valacyclovir in peritoneal dialysis: a pharmacokinetic study.

Valacyclovir is an effective oral agent for the treatment of herpes virus infection, however, the pharmacokinetics of the drug are altered in renal failure. It is increasingly recognized that dose adjustment of oral valacyclovir in renal failure is necessary to avoid neurotoxicity. We studied this drug in a continuous ambulatory peritoneal dialysis (CAPD) and immunocompromised patient. She developed neurotoxicity with an adjustment dosage of valacyclovir for a cutaneous zoster infection. The elimination half-time (15 h) was similar to that reported for end-stage renal disease patients, while the steady-state volume of distribution (85 l) and the area under the curve concentration (127 mg/l.h) were greater. The mean CAPD dialysance was only 5.27 ml/min with less than 1% of an administered dose being recovered in the 24-hour dialysate. 48 h after interrupting treatment, she recovered normal neurological status and 500 mg of valacyclovir every 2 days was effective and well tolerated.

Acyclovir↗
PubMedDate not supplied

[Renal tolerance of cidofovir].

Renal failure, proteinuria and proximal tubular acidosis are the features of cidofovir renal toxicity, its main side-effect. Proteinuria occurs in more than 40 per cent of patients and correlates with early renal dysfunction. A fall in serum potassium, bicarbonate, uric acid, calcium and phosphorus levels associated with glucosuria is the hallmark of proximal tubular acidosis. Most of the patients exhibit only glucosuria. Renal failure, diagnosed in 12 per cent of treated patients, is a late feature, usually discovered after the onset of proteinuria and glucosuria. Prevention of cidofovir-induced renal toxicity involves a search for other risk factors, probenecid treatment, and requires an optimal hydration status.

Acidosis, Renal Tubular↗
PubMedDate not supplied

[Renal tolerance of iodinated low osmolality contrast agents. Clinical and experimental aspects].

The low osmolality iodinated contrast agents (ICA), ionic or non ionic are now suggested too replace the usual high osmolality ICA. The main arguments are the better clinical tolerance and a lower renal toxicity. Recent experimental studies have clearly demonstrated that the low osmolality ICA presents a lower renal toxicity. On the rat, we have confirmed that the in vivo renal toxicity of low osmolality ICA, is lower than the high osmolality ICA toxicity. It is clearly demonstrated on man than the enzyme urinary excretion and proteinuria are little or not modified by the low osmolality ICA, but both are increased by high osmolality ICA. These changes are found with a normal glomerular filtration flow. No difference are noted in the creatinine concentration and clearance follow-up. However it is possible that the necessary population of patient to get statistically significative differences between both agents can be superior to the number of patients studied. In clinical practice, we think, that low osmolality ICA must be used for patients presenting one or several risk factors of acute renal failure.

Animals↗
PubMedDate not supplied

[Pharmacokinetics of 3'-azido-3 deoxy-thymidine (AZT) in a patient undergoing hemodialysis].

Zidovudine (AZT) is the only effective drug in the treatment of AIDS. No data are available on the pharmacokinetics of this drug in patients with end-stage renal disease (ESRD). We report on the pharmacokinetics of zidovudine between sessions of hemodialysis and during the procedure in one patient with ESRD. In 1987 a 40-year-old man with ESRD treated with hemodialysis had the AIDS-related complex. The T4/T8 ratio was 0.49. An enzyme-linked immunosorbent assay and Western Blot studies revealed IgG antibodies specifically directed against HIV. The patient was then treated with zidovudine (100 mg three times daily). Studies of the pharmacokinetics of the drug, conducted between hemodialysis sessions, were performed on days 1 and 14 after the start of zidovudine treatment. Paired arterial and venous blood samples were obtained simultaneously one hour after the start of a hemodialysis session on day 20. The peak and the trough concentrations of zidovudine were 0.61 and 0.15 microgram per milliliter, respectively. We observed a marked accumulation of the main metabolite of zidovudine, G-AZT, with a concentration of about 65 micrograms per milliliter on day 14. The half-life was 2.9 hours. The hemodialysis clearance of zidovudine and its metabolite were 102 and 71 ml per minute, respectively. The half-life of zidovudine was three times longer in our patient than in a normal subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗