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Biomedical subjects

H G Sieberth

Publications and source records attributed to H G Sieberth.

At least 19 recordsLinked to original sources
PubMed1992

Influence of oral contraceptive agents on kidney function and protein metabolism.

The present study was an investigation of the effect of oral contraceptives on kidney function as well as a brief examination of protein metabolism, since glomerular filtration rate depends to a large extent on daily protein intake. 28 healthy women not taking contraceptives and 46 healthy women (aged 20-28 y) on one of three different types of oral contraceptive (combination preparations) were investigated [Minulet/Femovan, Marvelon, Diane]. In all groups on oral contraceptives the endogenous creatinine clearance was significantly increased. The potassium excretion rate was significantly elevated in the groups taking Marvelon and Diane, and the sodium excretion rate was significantly increased in those on Minulet/Femovan and Diane. In all groups on contraceptives the albumin excretion rate was numerically but not significantly elevated. No significant differences were found in the daily oral protein intake or the nitrogen excretion rate on comparing the groups taking contraceptives with the control group. However, the ratio nitrogen excretion rate/daily protein intake was significantly increased in those on Minulet/Femovan and Diane. The study has shown that besides their various effects on renal tubular function, oral contraceptives are able to increase the glomerular filtration rate, and certain types have a protein catabolic effect.

Adult↗
PubMed1992

Serial kidney biopsies in patients with nephrotic syndrome treated with cyclosporin.

A total of 21 patients with severe steroid-resistant or steroid-dependent nephrotic syndrome have been treated with cyclosporin (CsA) over a period of 6 to 71 months. A permanent treatment was started in patients with complete [c] (proteinuria less than 0.3 g/day) or partial [p] (0.3 to less than 3.0 g/day) remission. In four cases proteinuria was markedly reduced but still greater than 3 g/day. Informed consent was obtained and all patients agreed to further control biopsies. Out of 14 patients treated for longer than 6 months, a fall in creatinine clearance was seen in three cases, including two patients with focal sclerosis who required dialysis treatment. Control biopsies were performed once in 11 and twice in seven patients. In two cases definite CsA-related damage was diagnosed after 1 and 24 months of treatment. Possible CsA-induced damage could not be excluded in three additional cases. In all other biopsies no CsA-related alterations could be demonstrated up to 47 months of treatment. The mean values of the creatinine clearance showed no deterioration. The drop off in a few cases has been related to the basic disease.

Adolescent↗
PubMed1992

Effect of fluoride on aluminum-induced bone disease in rats with renal failure.

Aluminum (Al) accumulation in renal failure is an etiological factor in the pathogenesis of low turnover bone disease. Aluminum-induced impairment of mineralization has been related to a reduced extent of active bone-forming surface. The present study investigated the effect of fluoride, a potent stimulator of osteoblast number, on the toxicity of aluminum in rats with renal failure (Nx). Following a large parenteral aluminum load (3.2 mg/kg x day) over a period of nine weeks, bone histomorphometry of vertebral cancellous bone revealed a severe low-turnover osteodystrophy as evidenced by a fall in osteoblastic osteoid surfaces and mineral apposition rates. Concurrent administration of fluoride [20 mg/liter (F20) or 40 mg/liter (F40) supplied with the drinking water] resulted in a significant increase in the number of osteoblasts (Nx+Al+F40 vs. Nx+Al, 33.75 +/- 2.83 vs. 1.81 +/- 0.43 mm-1, P less than 0.001) together with an overall reduced deposition of aluminum in bone (469.3 +/- 24.6 vs. 592.2 +/- 28.3 micrograms/g, P less than 0.01). However, there was an increase in the fraction of osteoid surface exhibiting stainable aluminum at the bone-osteoid interface (70.7 +/- 7.1 vs. 44.3 +/- 6.0%, P less than 0.005). Fluoride-exposed rats accumulated a significantly larger osteoid volume, suggesting an exacerbation of the osteomalacic lesion, and furthermore, dynamic histomorphometric parameters remained depressed. These results indicate that fluoride has a distinct effect on the pattern of aluminum deposition in bone. In addition, fluoride antagonizes the aluminum-induced reduction in osteoblast number but provides no amelioration of the impaired mineralization in aluminum-intoxicated rats. Thus, in this model a decrease in the extent of osteoblast surface does not account for the development of aluminum-related bone disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1992

Influence of ramipril on plasma atrial natriuretic peptide, antidiuretic hormone, angiotensin II and aldosterone in patients with chronic congestive heart failure.

UNLABELLED: In an open trial 5 mg ramipril daily for 2 weeks was administered to 11 patients with congestive heart failure. 24-hour plasma profiles of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), angiotensin II (Ang II) and aldosterone (Aldo) were determined before and on days 1 and 15 of ramipril treatment, respectively. Urinary sodium excretion was also measured at the same time points. There were no relevant differences in the 24-hour profiles of ANP and ADH. Ang II values dropped as expected on the first day of ramipril treatment from 11.2 pg/ml to 2.9 pg/ml at 3 h post administration and from 6.7 pg/ml (predose) to 1.8 pg/ml at 2 h post administration on day 15. Plasma aldosterone values increased slightly from day 1 to day 15, sodium excretion increased from 125.9 mmol to 166.5 mmol/24 h; however, both changes in the 24-hour profiles were nonsignificant. A clinically relevant improvement in the severity of CHF was observed. From a total of 121 reported symptoms according to McKee et al., 35 showed an improvement; 81 remained unchanged, in only 5 symptoms a deterioration was observed. According to the NYHA-classification 5 patients improved from grade III to II, 6 remained unchanged. CONCLUSION: ACE inhibition does not induce changes in ANP or ADH levels in the resting state while Ang II decreases. A slight increase in aldosterone levels may be due to increased sodium excretion.

Aged↗
PubMed1992

Sonographic evaluation of gallbladder motility in patients with end-stage renal disease on haemodialysis.

Thirty nine patients with end-stage renal disease on haemodialysis therapy with upper gastrointestinal symptoms were investigated for gallbladder motor function as the cause of their symptoms using cholecystosonography in fasting state, after a cholecystokinetic agent (BILOPTIN fatty meal) and after a smooth muscle relaxant (BUSCOPAN). Forty healthy individuals served as a control group. No significant difference was found between dialysis patients and healthy controls regarding the gallbladder area during fasting state, or the variation in the area of gallbladder during maximal contraction and dilatation. However, the patients on dialysis therapy of longer duration had stronger gallbladder contraction in response to a cholecystokinetic agent. Serum gastrin concentrations were increased in haemodialysis patients, but there was no consistent relationship between serum gastrin and gallbladder motility. The upper gastrointestinal symptoms of dialysis patients are unlikely to be due to disturbed gallbladder motility.

Adult↗
PubMed1992

Secondary hyperparathyroidism and sonographic evaluation of parathyroid gland hyperplasia in dialysis patients.

Ninety-six hemodialysis patients were examined by ultrasonography of the parathyroid glands to study the prevalence of parathyroid gland hyperplasia and to assess the relevance of sonography in the evaluation of secondary hyperparathyroidism. The results were compared with clinical, biochemical and radiological parameters. Thirty-two (33.3%) patients had sonographically enlarged glands. Of them 19 had 1 and 13 had 2 and more enlarged glands. Patients with enlarged glands, compared to those with undetected glands, had a significantly higher frequency of bone and joint pains (65.5% vs 40.6%), radiological features of hyperparathyroid bone disease (in hands 28.1% vs 6.9%, in acromioclavicular joints 37.5% vs 13.6%) and higher levels of intact serum parathyroid hormone (1-84) concentration (52.8 +/- 47.9 pmol/l vs 18.1 +/- 18.0 pmol/l) and serum alkaline phosphatase concentration (260.2 +/- 201.1 U/l vs 129.8 +/- 127.3 U/l). Those with enlarged glands had been on dialysis for a longer period (87.7 +/- 51.0 months vs 62.5 +/- 47.4 months). The severity of secondary hyperparathyroidism increased with the number of enlarged glands. Our study shows that ultrasonography is a useful noninvasive screening method for the evaluation of secondary hyperparathyroidism in patients on hemodialysis and that sonographically enlarged glands may be a measure of the severity of secondary hyperparathyroidism.

Female↗
PubMed1992

Induction of intestinal mucosal atrophy by difluoromethylornithine: a nonuremic model of enhanced aluminum absorption.

The intestinal absorption of aluminum (Al) appears to be enhanced in the uremic rat. Since atrophic changes of the intestinal mucosa have been observed in uremia the present study investigated whether intestinal atrophy induced by difluoromethylornithine (DFMO), a specific inhibitor of ornithine decarboxylase, could affect the absorption of Al. DFMO supplied with the drinking water (5%) to rats with normal renal function for 9 days resulted in a reduced number of microvilli with definite morphological alterations in small intestinal mucosa. Following an oral load of Al urinary excretion rates and 1-hour postload serum concentrations of Al were increased in DFMO-treated rats as compared to controls suggesting enhanced absorption of Al. Pattern and degree of urinary Al excretion as well as ultrastructural alterations of the intestinal mucosa were similar in DFMO-treated rats and uremic rats. The model of DFMO-induced intestinal alterations suggests that structural lesions of the intestine may be involved in the enhanced absorption of Al in uremia.

Aluminum↗
PubMed1992

Immunoreactive parathyroid hormone after volume change in normo- and hypotensive hemodialysis patients.

The effects of reduced blood volume during hemodialysis on circulating immunoreactive parathyroid hormone (PTH) were determined in relation to changes in blood pressure and heart rate in normo- and hypotensive patients with end stage renal failure. During dialysis the plasma concentration of PTH did not change in normotensives, while PTH increased significantly in patients with a fall in blood pressure during a 25% reduction in effective intravascular volume. The blood volume was measured continuously during hemodialysis using the authors' hemoglobin measurement system. The decrease in blood volume in both groups was comparable. The results suggest that secretion of PTH during hemodialysis may play a role in hemodynamic instability during hemodialysis.

Adult↗
PubMed1991

Calcium carbonate as a phosphate binder in dialysis patients: evaluation of an enteric-coated preparation and effect of additional aluminium hydroxide on hyperaluminaemia.

Calcium carbonate has been successfully used as a phosphate binder in patients with chronic renal failure; however, a high frequency of hypercalcaemia has been reported. To study the effects of calcium carbonate preparations with different dissolution characteristics on the incidence of this side effect, we conducted a double-blind, crossover trial in 21 patients undergoing chronic haemodialysis. Aluminum hydroxide therapy was replaced with calcium carbonate. The subjects then randomly received either an enteric-coated or a gastric-coated preparation. Calcium carbonate (3.1-3.6 g/d) controlled serum phosphate concentrations as effectively as aluminium hydroxide (2.9 g/d). Concurrently, there was a significant rise in mean serum calcium and a fall in serum concentrations of both parathyroid hormone and osteocalcin, the latter suggesting a decrease in bone turnover. Overall, hypercalcaemic episodes developed in 9 patients (43%) and occurred at a considerable frequency (33 episodes per 100 patient-months) during treatment with the gastric-coated formulation. Following conversion to enteric-coated calcium carbonate (3.6 g/d) patients had fewer occurrences of hypercalcaemia (12 episodes per 100 patient-months, P less than 0.05) and, as compared to the gastric-coated preparation, increases in serum calcium greater than 3.00 mmol/l were not observed at all. Hyperaluminaemia was regressive during therapy with calcium carbonate, but addition of small doses of aluminium hydroxide caused a large rise in serum aluminium concentrations after infusion of desferrioxamine, indicating an enhanced rate of absorption or aberrant compartmentalization of aluminium. We conclude that calcium carbonate can control hyperphosphataemia in dialysis patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1991

Pharmacokinetics and pharmacodynamics of cisapride in patients undergoing hemodialysis.

Twenty-two patients who were receiving hemodialysis were studied in three groups of eight subjects each to assess the pharmacokinetics during the dialysis-free interval and during hemodialysis treatment and to assess the pharmacodynamics of cisapride. Cisapride and its metabolite norcisapride were measured by use of HPLC and gas chromatography, respectively. The pharmacodynamic effect of cisapride was measured by means of radionuclide gastric emptying. After a single oral dose of 20 mg the terminal half-life of cisapride was 9.6 +/- 3.3 hours, the volume of distribution was 4.8 +/- 3.3 L/kg, the total oral plasma clearance was 380 +/- 161 ml/min, the area under the curve was 1024 +/- 447 ng.hr/ml (mean +/- SD). Norcisapride only could be detected in the dialysate (0.36 +/- 0.067 mg) and was eliminated by a hemodialysis clearance of 34.7 +/- 7.9 ml/min. Cisapride reduced gastric retention from 77.6% +/- 21.1% to 43.7% +/- 18.2% of maximum filling (40 minutes after meals) and normalized the abnormal gastric emptying time in patients receiving dialysis. Cisapride dosage adjustment or substitution after hemodialysis is not necessary.

Adult↗
PubMed1991

Hyperaluminaemia in critically ill patients: role of antacid therapy and impaired renal function.

A significant rise in serum concentrations of aluminum was demonstrated in 23 patients prophylactically treated with the antacid magaldrate, whereas no increase in serum aluminium was observed in another 26 critically ill patients, in whom the use of antacids was avoided. In parallel, urinary excretion rates of aluminum rose to values close to maximum 72 h after antacid therapy had been started. Hyperaluminaemia was most marked in patients with acute renal failure undergoing continuous haemofiltration, but a significant increment in serum aluminium was also noted in patients with impaired renal function in the predialytic state. In the latter group and in patients with normal renal function there was a significant negative correlation between urinary excretion rates of aluminium and creatinine clearance after 48 h of treatment suggesting an enhancement of gastrointestinal absorption of aluminium in the presence of chronic renal failure. Maximum serum concentrations of aluminium did attain critical values in some patients with acute renal failure, but no overt signs of aluminium toxicity were noted. However, in light of both, possible subtle toxicity and enhanced absorption of aluminium in critically ill patients with renal failure, the prophylactic use of antacids in this setting should be re-evaluated cautiously.

Acute Kidney Injury↗
PubMed1991

Effect of lactate on the absorption and retention of aluminum in the remnant kidney rat model.

In previous investigations we found the gastrointestinal absorption of aluminum (Al) to be enhanced in uremic rats and this phenomenon could not be attributed to either calcitriol deficiency or secondary hyperparathyroidism. The purpose of this study was to examine whether carboxyl ligands such as lactate could affect the absorption of A1 in our model and, if so, whether this would impose additional alterations on the A1 absorption in uremia. Uremic rats and controls were studied with single oral loads of either A1 chloride or A1 lactate and, subsequently, urinary A1 excretion was measured for 5 days. Compared with Al chloride, administration of A1 lactate resulted in significantly higher urinary excretion rates of A1 in uremic rats (55.5 +/- 22.7 vs. 27.4 +/- 7.0 micrograms; 2.06 +/- 0.84 vs. 1.01 +/- 0.26 mumol) and in controls (23.6 +/- 8.5 vs. 11.9 +/- 4.3 micrograms; 0.87 +/- 0.31 vs. 0.44 +/- 0.16 mumol). However, with either A1 load the recovery of A1 from urine was substantially higher in uremic animals. In contrast, only in controls was there a more pronounced rise in serum A1 concentrations following ingestion of A1 lactate, whereas in uremic rats this increase had a similar magnitude following A1 chloride and A1 lactate, suggesting a larger apparent volume of distribution of the latter. Adjustment of the pH of the A1 lactate-containing solution to 7.0 or oral administration of sodium lactate together with A1 chloride yielded essentially similar results. These observations indicate that the enhanced intestinal absorption of A1 in uremia is further augmented by lactate regardless of the mixture of hydroxolactato complexes employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1991

Influence of ramipril on renal function in patients with chronic congestive heart failure.

Ramipril was administered to 13 patients, aged 49-80 years, weighing 53.5-90.3 kg, with congestive heart failure (CHF) for 2 weeks in an open trial. One patient dropped out after day 1 and another accidentally received another angiotensin-converting enzyme (ACE) inhibitor, so that 11 patients remained for analysis. Each patient received 5 mg of ramipril daily for 2 weeks, followed by a 1-week washout period. Urine was collected in 4-h fractions for 12 h followed by a 12-h fraction on days 1, 8, and 15. Creatinine clearance, as well as the excretion of albumin and the urinary brush border enzymes gamma-glutamyl transferase (GGT), alanine aminopeptidase (AAP), N-acetyl-beta-D-glucosaminidase (NAG), and lactate dehydrogenase (LDH) were determined. The values for albumin excretion, creatinine clearance, GGT, AAP, NAG, and LDH obtained for the various days during the time course before and during multiple dosing were subjected to an analysis of variance followed by Scheffe's test for means. Daily albumin excretion decreased during treatment with ramipril from 23.8 +/- 27.4 mg/24 h (baseline) to 12.9 +/- 15.1 (day 1), 10.8 +/- 15.6 (day 8), and 12.4 +/- 12.7 mg/24 h (day 15). The differences were significant (alpha = 0.05) when compared to pretreatment albumin excretion. Creatinine clearance increased from 78.8 +/- 38.3 ml/min (baseline) to 82.4 +/- 34.6 (day 1), 85.1 +/- 28.5 (day 8), and 91.7 +/- 36.4 ml/min (day 15). The change on day 15 was significant (alpha = 0.05) when compared to pretreatment values.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosamine↗
PubMed1991

Intragastric long-term pH-metry in hemodialysis patients. A study with famotidine.

The onset and duration of famotidine action were studied in 14 hemodialysis (HD) patients and 16 healthy controls (control group: CG) who were examined by ambulatory intragastric 24-hour pH-metry. 20 mg famotidine was administered i.v. 90 min after HD in the afternoon (AN; 2 p.m.; n = 8) or evening (E; 8 p.m.; n = 6), followed by a standard meal. Mean onset of action in the AN and E groups of the HD patients was 90.3 +/- 28.2 min and 98.8 +/- 29.8 min, and in CG patients 36.3 +/- 11.9 min and 53.6 +/- 22.3 min, respectively (p less than 0.05). Duration of action in the AN and E groups of the HD patients was 22.7 +/- 2.1 h and 21.6 +/- 2.6 h, and in CG patients 6.0 +/- 1.1 h and 11.4 +/- 1.6 h, respectively (p less than 0.05). Our study showed a retarded and prolonged action of famotidine in HD patients. The time of administration of famotidine had no effect on its action in HD patients. This is in contrast to normal subjects in whom evening administration delays the onset and prolongs the duration of famotidine action in comparison to afternoon administration.

Adult↗