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Biomedical subjects

G Deray

Publications and source records attributed to G Deray.

At least 145 records · Page 8Linked to original sources

[Can cisplatin renal toxicity be prevented?].

Cis diamminedichloroplatinum (CDDP) is a widely used anticancer agent particularly effective in the treatment of solid tumors. Dose limiting toxicity of CDDP was shown to be renal. Numerous methods to reduce this nephrotoxicity have been proposed. Hydration remains the best protection against acute CDDP nephrotoxicity in both the clinical and experimental setting. In man, no controlled studies have demonstrated the efficacy of furosemide and mannitol in the reduction of the CDDP renal toxicity. Studies have shown, however, that sodium thiosulfate offers some nephroprotection. To date, no controlled studies have demonstrated any benefit in the use of calcium channel blockers on CDDP renal toxicity in man. New drugs such as carboplatin have recently been introduced that theoretically have less renal toxicity, but evidence to support these claims are lacking. CDDP nephro protection remains a problem of current clinical interest and has yet not to be totally resolved.

Calcium Channel Blockers↗

Renal vasoconstriction after low and high osmolar contrast agents in ischemic and non ischemic canine kidney.

We have assessed the effect of contrast media on renal blood flow before and after inducing renal ischemia. Diatrizoate, iopamidol and ioxaglate were injected within 15 seconds at 20 min intervals, at the dose of 1 ml/kg during a control period and 15 min after applying an aortic clamp to reduce the renal perfusion pressure to 70 mmHg. During the control period iopamidol, ioxaglate (17 +/- 13%) and diatrizoate (16 +/- 2%) induced a comparable decrease in renal blood flow (RBF). During the ischemic period the effects of diatrizoate on renal hemodynamic were dramatically enhanced. Ioxaglate andiopamidol induced a 20 +/- 12 and a 32 +/- 9% decrease in RBF at 1 minute, respectively. Iopamidol induced an increase in renal vascular resistance (RVR) from 0.8 +/- 0.08 to 1.46 +/- 0.26 mmHg min/ml (p less than 0.05). Ioxaglate induced an increase in RVR from 0.8 +/- 0.09 to 1.36 +/- 0.38 (p less than 0.05). Diatrizoate induced a 77 +/- 10% decrease in RBF and a maximum increase in RVR at 1 minute from 0.9 +/- 0.09 to 26 +/- 12 mmHg min/ml. There was still a 36 +/- 14% and a 23 +/- 13% decrease in RBF 10 and 20 min after diatrizoate administration. These changes were significantly higher than those observed with all contrast media during the control period and low osmolar contrast media during the ischemic period. We have thus shown that ischemia potentiates the renal vascular effect of contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗

[Drug-induced interstitial nephropathy with nephrotic syndrome].

A new syndrome is which immunoallergic interstitial nephropathy is associated with nephrotic syndrome has recently been described. The interstitial nephropathy is usually due to the consumption of non steroidal anti-inflammatory drugs, and it is characterized by interstitial lesions associated with minimal glomerular lesions. The typical clinical complex includes nephrotic syndrome, renal impairment, eosinophilia, microscopic haematuria, leucocyturia and, more rarely, clinical signs of hypersensitivity. The outcome is favourable as a rule, with recovery of the renal function ad integrum and complete recession of the nephrotic syndrome. The pathogenesis of the syndrome is no entirely clear, but it probably implies a delayed hypersensitivity reaction. Treatment consists of withdrawing the responsible drug(s) and applying medical intensive care methods. Whether or not corticosteroids influence the rapidity and quality of recovery remains uncertain.

Acute Disease↗

Atrial natriuretic peptide level and intracardiac pressure in cardiac transplant recipients.

Blood pressures and plasma atrial natriuretic peptide (ANP) concentrations have been measured in venous and intracardiac sites in 11 patients (10 men and 1 woman) given cardiac transplants. The mean plasma ANP level was 214.4 pg.ml-1 in the superior vena cava and 281 pg.ml-1 in the right atrium. This significantly higher level was maintained in the right ventricle (269) and in the pulmonary artery (295). The level in controls was 25 pg.ml-1. Intra cardiac and mean arterial pressures were in normal range in all patients, and there was no correlation between plasma ANP level and intracardiac pressure. The data suggest that in cardiac transplant patients right atrial pressure does not have a primary role in releasing ANP. The transplanted heart is denervated and remains so for many months after operation, thus suggesting that innervation is not obligatory for ANP secretion. Further studies are required to determine the relative contribution of donor and recipient atrial tissues to ANP secretion.

Atrial Natriuretic Factor↗

Beta-adrenoceptor blockade potentiates exercise-induced release of atrial natriuretic peptide.

The effect of a non selective and a cardio-selective beta-blocker on basal and exercise-stimulated plasma atrial natriuretic peptide concentrations in healthy volunteers has been studied. Nine healthy volunteers received single oral doses of 5 mg tertatolol, 100 mg atenolol or placebo, at one week intervals, in a double blind cross over trial. At rest plasma atrial natriuretic peptide, aldosterone, antidiuretic hormone and cyclic GMP concentrations and plasma renin activity were not modified by the treatments. During exercise plasma atrial natriuretic peptide concentrations were significantly increased by each treatment, the increment being significantly greater on beta-blockers than on placebo. The rise in atrial natriuretic peptide was 72% after placebo (from 24 to 42 pg/ml), 184% after atenolol (from 30 to 86 pg/ml), and 183% after tertatolol (from 34 to 95 pg/ml), respectively. Thus, the study has shown that in healthy subjects the plasma natriuretic peptide concentration is increased by exercise and that the increase is considerably and equally potentiated by selective and non selective beta-adrenoceptor blockade. The effect may be mainly due to a reduction in ventricular contractility with an increase in atrial pressure. The beta-blockers did not influence the resting plasma atrial natriuretic peptide levels, which suggests that in healthy subjects basal atrial natriuretic peptide secretion is not controlled via beta-receptors.

Adrenergic beta-Antagonists↗

Cicletanine does not affect plasma atrial natriuretic peptide concentration in healthy subjects.

The effect of 50 and 150 mg cicletanine, a new vasodilator antihypertensive, on plasma atrial natriuretic peptide (ANP), cyclic GMP and antidiuretic hormone has been investigated at rest and during standardized exercise, in a double blind cross over study in healthy subjects. Exercise significantly increased in plasma ANP, cyclic GMP and antidiuretic hormone concentrations, and cicletanine did not affect any of them either at rest or during exercise. Since the alpha-1 adrenoceptor blocker prazosine decreases, beta-adrenoceptor blockers increase and the vasodilator cicletanine does not alter the plasma ANP response to exercise, it is suggested that adrenergic receptors may be directly involved in the regulation of ANP secretion.

Administration, Oral↗

Atrial natriuretic factor in patients with acromegaly.

In acromegaly the plasma volume is chronically elevated and it returns to normal when the disease is successfully treated. To define the role of ANF in such a chronic disorder of extracellular fluid volume homeostasis the plasma level was assayed in 37 acromegalic patients with active or inactive (successfully treated) disease. Five patients were studied before and after therapy. The effects of acute change in sodium-fluid status on plasma ANF levels was examined in 7 active and 4 inactive acromegalic patients and in 7 healthy subjects. As compared to 14 patients with inactive acromegaly, 23 patients with active acromegaly had an expanded plasma volume (n = 12; 50.1 vs 37.6 ml.kg-1 BW) and an increased blood concentration of growth hormone (n = 23; 22.5 vs 2.1 ng.ml-1). Plasma ANF concentrations in active and inactive acromegalic patients (33.2 and 26.6 pg.ml-1, respectively) did not differ significantly from one another or from the level in the controls (26.9 pg.ml-1). In those patients there was no correlation between plasma volume and ANF level. Infusion of 21 isotonic saline in 2 h led to a similar, significant increase in ANF levels in active (from 26.2 to 72.4 pg.ml-1) and in inactive acromegalic patients (from 33.6 to 96.7 pg.ml-1) as well as in healthy subjects (from 21 to 70.6 pg.ml-1). Successful treatment reduced the plasma volume (from 49.2 to 35.8 ml.kg-1 BW) and growth hormone level (from 10.1 to 2.6 pg.ml-1), while the ANF level remained unchanged (from 33.8 to 35.5 pg.ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗

Renal effects of S10036 in man.

The renal hemodynamic and tubular effects of S10036 (fotemustine) were evaluated in seven patients with advanced malignancy. Initial evaluation carried out prior to treatment and repeated 1 day after the first fotemustine infusion and 7 days after the second included clinical, haematological parameters, liver-function tests, and determination of the glomerular filtration rate, renal blood flow and enzymuria. The glomerular filtration rate was 108 +/- 3.7 ml/min before treatment and remained stable after the first (117 +/- 5 ml/min) and second (124 +/- 6 ml/min) fotemustine infusions. Renal blood flow and urinary beta 2-microglobulin and N'-acetylglucosaminidase excretion were also not modified by fotemustine administration. We conclude that fotemustine does not acutely alter renal haemodynamics, nor does it have direct tubular toxicity.

Acetylglucosaminidase↗

A role for adenosine calcium and ischemia in radiocontrast-induced intrarenal vasoconstriction.

These studies were designed to test the hypothesis that adenosine and calcium are important in mediating radiocontrast-media-associated reduction in renal blood flow (RBF) in the dog. Intravenous verapamil (V) and diltiazem (DTZ) infusion significantly attenuated the magnitude of the vasoconstrictor response observed after each intrarenal contrast media (CM) injection. (First injection: -47 +/- 8% control vs. -14 +/- 3% V, p less than 0.03; -38 +/- 4% control vs. -19 +/- 3% DTZ, p less than 0.02. Second injection: -33 +/- 6% control vs. -12 +/- 1% V, p less than 0.03; -32 +/- 5% control vs. -17 +/- 2% DTZ, p less than 0.03. Third injection: -32 +/- 6% control vs. -11 +/- 5% V, p less than 0.03; -38 +/- 5% control vs. -10 +/- 5% DTZ, p less than 0.02). Furthermore, V and DTZ almost completely abolished the increase in renal vascular resistance (RVR) induced by each CM administration. Theophylline also significantly attenuated the magnitude of the vasoconstrictor response observed after CM injection (first injection: -31 +/- 3% control vs. -12 +/- 3% theophylline, p less than 0.05; second injection: -26 +/- 3% control vs. -12 +/- 3% theophylline, p less than 0.03). Similarly, theophylline blunted the increase in RVR induced by CM injection. In addition, theophylline inhibited exogenous adenosine-induced decrease in RBF (-61 +/- 10% and -26 +/- 1% decrease in RBF without and with theophylline, respectively). In contrast, dipyridamole significantly enhanced the vasoconstriction induced by CM (first injection: 25 +/- 3% control vs. 49 +/- 4% dipyridamole; second injection: 31 +/- 3% control vs. 48 +/- 4% dipyridamole p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗

Renal effects of radiocontrast agents in rats: a new model of acute renal failure.

The objectives of this study were first to develop a reproducible and reversible model of acute renal failure following contrast medium infusion in the rat; second to use that method to compare the nephrotoxicity of low- and high-osmolar contrast agents. Contrast media or saline were perfused in the aorta while a clamp was applied on the aorta just above the renal artery. Three minutes of renal ischemia with or without infusion of isotonic saline induced no change in serum creatinine and a slight and transient decrease in creatinine clearance at 24 h. Urinary N-acetyl glucosaminidase (NAG) excretion was not modified in this control group. All 17 kidneys which were examined were normal. 2,100 mosm/kg hypertonic saline induced a significant increase in serum creatinine and a significant decrease in creatinine clearance (from 1.8 +/- 0.1 to 0.8 +/- 0.1 and 1.0 +/- 0.2 ml/min at 24 and 48 h, respectively). Urinary NAG excretion increased from 23 +/- 18 to 48 +/- 20 and 8 +/- 4 mumol h-1/mmol creatinine at 24 and 48 h, respectively (p less than 0.05). Histologic analysis of 5 kidneys revealed acute tubular necrosis (n = 3) and no histologic abnormalities (n = 2). Diatrizoate induced an acute and reversible renal failure. Creatinine clearance decreased from 1.6 +/- 0.1 to 0.4 +/- 0.1 and 0.8 +/- 0.1 ml/min at 24 and 48 h, respectively (p less than 0.01). Urinary NAG excretion increased also significantly from 43 +/- 9 to 352 +/- 79 and 64 +/- 23 mumol h-1/mmol creatinine at 24 and 48 h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗

Renal and hemodialysis clearances of endogenous natriuretic peptide. A clinical and experimental study.

The purpose of the present study was to assess the plasma levels of atrial natriuretic peptide (ANP) in chronically uremic patients not submitted to dialysis and to determine the predialysis plasma concentration of ANP, the effect of ultrafiltration on plasma levels of ANP (hemodialysis, (HD), and the HD clearance of ANP in a population of adult patients treated with maintenance HD. The mean plasma ANP concentration (pg/ml) in HD was 370.2 +/- 35.5 pg/ml (mean +/- SEM) before HD and decreased to 165.3 +/- 15.2 after HD (p less than 0.01). Both values were significantly higher than in controls (28 +/- 2; n = 39). The changes in plasma ANP levels correlated inversely with those in plasma protein concentration (r = -0.53; p less than 0.03; y = 48.6 +/- 0.8 x). ANP clearance across the cuprophan membrane averaged 13 +/- 6.4 ml/mn. Resting plasma ANP values in the 16 uremic patients ranged between 16 and 277 pg/ml (124 +/- 11 pg/ml). These levels were significantly higher than those observed in controls (p less than 0.01). In these patients there was a highly significant correlation between serum creatinine and plasma ANP concentrations (p less than 0.01; r = 0.75; y = 0.2x + 3). Furthermore we report the results of the determination of the renal clearance of ANP in normal dogs. In all dogs a fall in plasma ANP concentration was recorded between the aorta (28.6 +/- 4.5 pg/ml) and the renal vein (14.2 +/- 2.7 pg/ml). The renal extraction ratio averaged 51.3 +/- 3.7%. Mean ANP renal clearance was 38.2 +/- 5.2 ml/mn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗