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Biomedical subjects

P Zech

Publications and source records attributed to P Zech.

At least 55 records · Page 3Linked to original sources

Cyclosporin A-sensitive nephrotic syndrome preceding Hodgkin's disease by 32 months.

A 20-year-old man developed a massive nephrotic syndrome, rapidly complicated by pulmonary embolism and septicemia. Two renal biopsies taken 3 months apart showed minimal change glomerulonephritis. Treatment with prednisolone 1.5 mg/kg/day failed to induce a sustained remission, then monotherapy with cyclosporin A (CsA, 5 mg/kg/day) was started. Complete remission was obtained after 15 weeks. CsA was gradually tapered to 3 mg/kg/day. Twenty-two months after starting CsA, a routine examination disclosed a right sub-clavicular lymph node, of which histological examination showed a class 4 large cell Hodgkin's lymphoma. CsA was abruptly withdrawn and a polychemotherapy resulted in lymphoma remission after four courses. Ten months later, Hodgkin's disease is currently in remission and there is no relapse of proteinuria.

Adult↗

Restrictions on use of creatinine clearance for measurement of renal functional reserve.

The increase of glomerular filtration rate after a 90-gram oral protein load was determined in 9 healthy individuals by simultaneous measurements of both creatinine (Ccr) and inulin (Cin) clearances, performed before and every 30 min during 4 h after the meat meal. This protein load resulted in a short 26% increase of Cin at 90 min, and a sustained 29% increase of Ccr from 90 to 240 min after load. Individual peak values of Ccr occurred later than those of Cin (Ccr: 189 +/- 19 vs. Cin: 127 +/- 19 min; p = 0.023). These discrepancies were related to an increase of serum creatinine, and a subsequent increase of the net tubular excretion of creatinine which accounted for up to 15% of the urinary creatinine. The creatinine content of red meat could lead to overestimation of renal functional reserve when measured by creatinine clearance only.

Adult↗

Pharmacokinetics of rilmenidine.

Rilmenidine, an alpha 2-adrenoceptor agonist, was studied (1 mg single dose) in order to determine the effects of pathology on its basic pharmacokinetic parameters. Because of the mainly renal elimination of rilmenidine, studies involved hypertensive, elderly hypertensive, renal insufficient and hepatic insufficient patients. Hypertension was found to influence neither the absorption, the distribution nor the elimination processes; the linearity in the range of 1 to 2 mg and the absence of accumulation in long-term treatment were confirmed. In contrast, in the elderly, the absorption phase was delayed. The slight decrease in the apparent volume of distribution (-12%), with a notable decrease in the apparent total clearance (-50%) led to a prolonged elimination half-life (+50%). In renal failure, linear relations between the degree of renal impairment and the elimination parameters were shown. These relations allow the evaluation of the predicted steady-state level of rilmenidine for a given degree of renal failure. In hepatic insufficiency, the modification of rilmenidine disposition concerned exclusively the elimination phase in which apparent clearance was decreased approximately 20%. In conclusion, these results lead to a decreased dosage regimen in patients with severe renal failure.

Absorption↗

Doxazosin in the treatment of patients with mild or moderate hypertension and mild or moderate renal insufficiency.

The antihypertensive efficacy and safety of doxazosin, a selective alpha 1-inhibitor, were assessed in 23 hypertensive patients with renal insufficiency. The study involved three phases: (1) a 2-week baseline period, (2) a 10-week period during which patients received doxazosin, 1 to 16 mg, once daily, and (3) a 4-week maintenance period. After 14 weeks of active treatment, systolic/diastolic blood pressures of efficacy evaluable patients were reduced by 8.9/9.2 and 4.6/9.1 mm Hg to final values of 153/90 and 149/91 mm Hg in the supine and standing positions, respectively. The mean dose of the efficacy evaluable patients was 9.8 mg/day. Eleven patients experienced one or more side effects, most of which were mild or moderate and disappeared or were tolerated with continued therapy. No clinically significant laboratory changes were apparent, and no trends were observed with regard to organ systems or correlations with dose or duration of treatment. There were no significant differences in serum creatinine levels between baseline and final visits. The overall lipid profile indicated a decrease in total cholesterol with increases in high-density lipoprotein cholesterol and the high-density lipoprotein/total cholesterol ratio. From baseline to final visit there was a highly significant reduction of 19% (p less than 0.05) in calculated risk scores for coronary heart disease on the basis of the Framingham equation.

Adrenergic alpha-Antagonists↗

The prognosis of renal vein thrombosis: a re-evaluation of 27 cases.

Twenty-seven patients with renal vein thrombosis were retrospectively studied to evaluate their long-term prognosis and relevant prognostic factors. Twenty-four patients presented with a nephrotic syndrome, and 15 had renal impairment (8 acute; 7 moderate). Ten patients had a previous history of proteinuria, and 14 of nephrotic syndrome. Renal biopsy performed in 20 patients, of whom 19 were nephrotic, showed membranous glomerulonephritis in 14, focal segmental glomerulosclerosis in three, minimal change glomerulonephritis in two, and periarteritis nodosa in one. Renal vein thrombosis was angiographically proven in all patients and was bilateral in 18, localised to the left renal vein in seven, and to the right in two. Thrombosis of the inferior vena cava was associated in seven patients. Ten patients were treated by anticoagulants alone, nine by surgical thrombectomy, seven by thrombolysis, and two did not receive any specific treatment. One patient underwent successively thrombectomy and then thrombolysis. Eleven patients died within the first 6 months, mainly from haemorrhagic complications (n = 5) or severe sepsis (n = 2). Survivors were followed up from 6 months to 19 years. Nephrotic syndrome improved or even disappeared in 12 patients, and renal function did not worsen throughout the follow-up in any patients. The main prognostic factors were initial renal function and type of nephropathy: patients with membranous glomerulonephritis had a significantly better renal function and a lower mortality rate than patients with other nephropathies. Initial renal insufficiency was significantly associated with a poor prognosis. There was no advantage, in terms of survival, kidney function and nephrotic syndrome, of either thrombectomy or thrombolysis over anticoagulants alone, despite two complete venous recanalisations after thrombolysis. Accordingly, patients with renal vein thrombosis from membranous glomerulonephritis should be treated by anticoagulants alone, since the long-term prognosis of this disease seems unaffected by intercurrent renal vein thrombosis. With respects to the risk-to-benefit ratio, thrombectomy should be avoided and thrombolysis considered only in patients with initial acute renal failure from acute renal vein thrombosis.

Adult↗

[Prognosis of renal vein thrombosis in the adult: influence of treatment].

The medical histories of 27 patients with renal vein thrombosis were evaluated retrospectively. Short and long term evolution as well as prognostic factors were analysed. 24 of the patients were suffering from a nephrotic syndrome, 15 from renal failure. In the 20 biopsies performed we observed: 14 cases of extramembranous glomerulonephritis, 2 cases of minimal glomerular lesions, 3 cases of segmental focal glomerulosclerosis and 1 periarteritis nodosa. The renal vein thrombosis was bilateral (18), left (7) or right (2). In 7 patients this was associated with thrombosis of the inferior vena cava. 9 patients were treated with anticoagulants alone, 9 underwent thrombectomy, 7 were treated by thrombolysis and 2 received no treatment. Within the first six months 11 patients died as a result of complications due to hemorrhaging (5), septic infection (2) or embolism (1) and 3 patients died of undetermined causes. The progression of the remaining patients was followed up over a period of 6 months to 19 years. In 12 patients, the nephrotic syndrome regressed and renal function did not deteriorate in any of the cases. The main causes for poor prognosis are the existence of initial renal failure and glomerulonephritis which is not extramembranous. Since the evolution of the glomerulopathy does not appear to be affected by extramembranous glomerulonephritis, renal vein thrombosis associated with this complication should be treated with anticoagulants alone. The risk-benefit ratio of thrombectomy leads us to conclude that this technique should be abandoned. Thrombolysis could be considered in cases where renal vein thrombosis is associated with acute renal failure.

Acute Kidney Injury↗

Influence of treatment by betaxolol on the renal response to postural changes in moderate hypertension.

Assumption of upright posture is known to be associated with significant variations in renal function, which are thought to be mediated through the stimulation of the renin angiotensin system. The effect of an eight-week treatment with betaxolol, a selective beta-blocker, was studied in patients with moderate hypertension and normal renal function. Betaxolol induced the expected changes in systemic hemodynamics and reduced supine plasma renin activity and aldosteronemia. The glomerular filtration rate showed no variation but the tubular reabsorption of sodium increased. The renal adaptation to postural changes (decrease in glomerular filtration rate, increase in sodium reabsorption and in plasma renin activity) was unaffected by treatment. It is concluded that betaxolol does not impair the renal response to a physiological stimulus such as change in posture.

Adult↗

Magnesuria induced by thiazides and the influence of triamterene.

The effects on magnesium excretion of 4 short-term diuretic treatments (methyclothiazide 2 mg either alone or associated with increasing doses of triamterene) were evaluated in 8 normal volunteers and compared to spontaneous variations during placebo administration. The thiazide exerted a small but significant magnesuric effect, which was prevented only by the lowest dose (25 mg) of triamterene. Larger doses had no protective effect on thiazide-induced magnesuria. Independently of their absolute effects on magnesium excretion, all diuretics impaired the normal ability of the kidneys to compensate fully for the expected changes in magnesium reabsorption induced by extracellular volume contraction.

Adult↗

[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↗

[Diffusion of ceftriaxone in the renal parenchyma].

Diffusion of ceftriaxone in renal parenchyma after IV injection (2 g) was studied in six patients with normal renal function, undergoing nephrectomy. Cortex and medulla of the kidney were studied. Blood samples, tissular fragments and urine were studied for drug concentration using HPLC and microbiologic assay 1, 12 and 24 h after injection. Both methods led to similar results. No difference in drug concentration was found between cortex and medulla. Tissular concentration of ceftriaxone remain higher than MIC for most Enterobacteriaceae strains until 24 h.

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↗