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Biomedical subjects

M Labeeuw

Publications and source records attributed to M Labeeuw.

At least 55 records · Page 3Linked to original sources

[Influence of acute administration of ramipril on the excretion of uric acid].

The influence of a new ACEI, Ramipril (R) on renal handling of UA was investigated. 13 hypertensives with normal renal function received either R (10 mg p.o.) or placebo (P). Arterial pressure (AP), GFR (Inulin clearance), Renal Plasma Flow (RPF, PAH clearance), UA urinary excretion (UAV) and fractional clearance (FeAU: UA clearance/GFR) were studied for seven hours after drug administration. GFR remained stable in all cases. R had no effect on sodium excretion rate. Compared to P, R significantly increased UAV by 25 p. 100, FeAU by 32 p. 100, RPF by 26.5 p. 100 and decreased mean arterial pressure (MAP) by 10 p. 100. ACE activity was maximally suppressed at 2 hours. More than 80 p. 100 of the maximal changes in UAU and FeAU were observed within the first two hours, while a progressive increase in RPF up to the fifth hour, and a progressive fall in MAP up to the fourth hour was evident. Except for PAM, all these changes were still present at the end of the study (seventh hour). In conclusion, Ramipril increases the fractional excretion of uric acid. This effect is observed independently of any change in sodium balance and preceeds by two to three hours the changes in renal hemodynamics. The simultaneous changes in FeAU and in ACE activity indicate that the effect on uric acid excretion is presumably due to the fall in angiotensin concentration.

Angiotensin-Converting Enzyme Inhibitors

[Local treatment of obstructive uric acid calculi].

Dissolution of uric acid calculi could be obtained by oral or parenteral urinary alcalinization, but this method cannot apply to the case of obstructive calculi. Nineteen obstructive calculi in 18 patients were treated by in situ alcalinization through a percutaneous nephrostomy catheter (PCN). Eight patients were initially anuric, 7 of whom from an obstructed solitary kidney and 1 from a bilateral obstructive lithiasis. Fifteen calculi were located in the ureter, 3 in the uretero-pelvic junction and 1 in the pelvis. After 48 h of urinary diversion through PCN, an isotonic sodium bicarbonate solution (14 g %) was continuously infused at an average flow rate of 2.8 l/24 h, through either an unique PCN, or a 2 PCN-irrigation circuit in the 7 cases with permanently obstructive calculus. Fifteen calculi (80%) were completely dissolved after 3 to 13 days of alcalinization (average 5.8 days). One large calculus was reduced by 3/4 and further removed by percutaneous lithotripsy. Three patients underwent ureterotomy after 9 to 11 days of uneffective treatment. Local alcalinization is an effective and non invasive treatment for obstructive uric acid calculi, and is logically associated with the necessary urinary diversion.

Aged

[Pharmacokinetics of ceftriaxone in hemodialysis].

The influence of hemodialysis on the pharmacokinetics of ceftriaxone was studied in 5 patients with chronic renal failure, with a glomerular filtration rate of less than 5 ml/min, and treated by regular hemodialysis. A single dose of 2 g ceftriaxone was administered IV at the end of a hemodialysis, and venous samples were drawn 12 and 24 h thereafter. Two hemodialysis were performed at the 44th (HD1) and the 92nd (HD2) hour, and blood samples were drawn simultaneously on arterial and venous sides of the dialyzer at the onset of HD1 and at the end of HD2. Plasma ceftriaxone concentrations were measured on each sample by both microbiological and chromatographic (HPLC) methods. In these patients, ceftriaxone kinetics are considerably longer than in normal subjects, with an elimination half-life of 16 h, an apparent distribution volume of 800 ml/kg, but without decrease of plasma clearance, except in one patient who had hepatic cytolysis at the time of injection. Plasma concentrations on both sides of dialyzers, or before and after hemodialysis, are not significantly different, and the mean hemodialysis clearance ranges between 26 and 30 ml/min/m2 dialyzer area. According to these data, the dose-interval between successive administrations of ceftriaxone 2 g IV should be 48 h in patients with chronic renal failure, and supplemental doses do not appear necessary after hemodialysis.

Adult

Evolution of renal function under chronic oral administration of labetalol.

The glomerular filtration rate (GFR, inulin clearance) and renal plasma flow (RPF, PAH clearance) were measured in 35 hypertensive patients during chronic administration of an alpha-beta-blocker, labetalol. No significant changes in GFR occurred but RPF increased significantly. The increase in RPF was positively correlated with the decrease in mean arterial blood pressure. Patients with renal failure showed changes similar to patients with normal renal function. Thus chronic treatment with labetalol, unlike most beta-blockers, can increase RPF, an effect which could be related to the alpha-blocking activity of the drug.

Administration, Oral

Acute renal effects of beta-blockers.

The effects on renal function of a single dose of six different beta-blockers (atenolol, propranolol, metoprolol, acebutolol, nadolol, and pindolol) have been evaluated in 51 hypertensive patients with normal glomerular filtration rate (GFR). Most drugs, except pindolol, induce a 10-20% decrease in GFR and renal plasma flow, although differences in the magnitude and the pattern of this fall are evident. The fractional excretion of sodium is generally depressed by 20-40%. These data suggest a limited renal tolerance of most beta-blockers during acute administration, irrespective of their pharmacological characteristics.

Adrenergic beta-Antagonists

Surgical versus medical treatment in renovascular hypertension. Retrospective study of 166 cases.

A retrospective study of 166 cases of renovascular hypertension was performed. Before 1979, 114 patients were treated for renovascular hypertension. Forty underwent surgery. In this group, therapy resulted in cure or improvement in 45% of the patients. Seventy-four patients underwent medical therapy: 88% of these patients had improvement of blood pressure when beta-blockers were used, but only 41% when they were not. More recently (from 1979 to 1983), 52 patients were treated for renovascular hypertension, of which 31 patients have been operated for fibromuscular renal artery stenosis (62%) or atherosclerotic renal artery stenosis (32%). In this group, 90% of the patients were considered to be cured or improved with a mean follow-up of 36 months. Eighteen of thirty-one patients underwent autotransplantation with satisfactory results on blood pressure control. Twenty-one patients were treated by antihypertensive drugs: 86% of the patients were improved or cured (71.5% of the patients had atherosclerotic lesions) with a mean follow-up of 46.8 months.

Adult

[Course of renal function in malignant hypertension. Effect of treatment. Study of 30 cases followed for 5 to 18 years].

Renal insufficiency is the most frequent complication of malignant hypertension (MHT). The initiation of effective hypotensive treatment is generally followed by a rapid improvement of renal functions, but the long-term evolution has been only rarely studied. A group of 30 patients was retrospectively selected on the following criteria: Malignant hypertension: mean DBP 138 +/- 20 mmHg, hypertensive retinopathy stage III-IV; Early renal insufficiency: mean Inulin clearance (CIN) 66 +/- 26 ml/min, mean PAH clearance (CPAH) 364 +/- 161 ml/min; Clinical and functional follow-up ranging from 5 to 18 years. Among these patients, two groups were defined according to the quality of BP control: good or fair responders (GR) with a DBP always less than 110 mmHg, poor responders (PR) with a DBP occasionally greater than or equal to 110 mmHg. The results show in the two groups an improvement of CIN at 3 years, followed by a stabilization then a decrease after the 6th year. However the early improvement is significantly lower in PR. Despite similar initial values (GR = 54.7 +/- 31.3; PR = 51.4 +/- 13.2), CIN remains always lower in PR (at 9 years = GR 72.4 +/- 30.6; PR 56.0 +/- 19.8). During the first 3 years, CPAH increases in GR, whereas it decreases in PR, resulting in significantly different values at 3 years. At 9 years, CPAH remains improved in GR (329.1 +/- 109.3 vs 281.7 +/- 173.8 initially) but decreased in PR (256.0 +/- 166.9 vs 307.3 +/- 119.5 initially). The parallel improvement of CIN and CPAH in GR confirms a favorable effect of BP control on early vascular lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Recurrent myalgias associated with cimetidine.

A chronically hemodialyzed patient experienced recurrent episodes of myalgia while on cimetidine treatment (400 mg/day). After two uneventful courses of cimetidine, the pain appeared at the end of a third fourteen-weeks long course. Severe myalgia occurred at the sixth week of a fourth exposure to cimetidine. Pain was predominant in the hip area, disappeared within a few days after withdrawal and recurred three weeks after resuming therapy. There was no sign of neurological involvement and CPK remained consistently normal. Ranitidine was subsequently administered for four months whereby the patient showed no symptoms of myalgia. This observation suggests that, in susceptible individuals, a progressive decrease in tolerance to cimetidine might occur with repeated courses.

Cimetidine

Hypercalcemia in 25 OH D3 treated patients receiving a calcium exchange resin.

Seven patients with advanced renal failure, six of whom were dialysed, received a cation exchange resin in the calcium cycle because of severe hyperkalemia, together with their usual preventive treatment of renal osteodystrophy, including 25 hydroxycholecalciferol. Hypercalcemia developed in four subjects within less than thirty days and disappeared within four days following the withdrawal of the resin. Patients who exhibited hypercalcemia had higher calcium intake, lower predialysis blood calcium and higher PTH values before introduction of the treatment. Three of the four hypercalcemic patients were diabetics. It is therefore advised to frequently monitor blood calcium when using calcium exchange resin in patients treated with vitamin D analogs.

Calcifediol