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H Strobach

Publications and source records attributed to H Strobach.

34 records · Page 2Linked to original sources
PubMed1989

Winner of the ESVS Prize 1988. Effects of prostaglandin E1 (PGE1) on experimental renal ischaemia.

A persisting incidence of acute renal failure has been observed after operative treatment of thoracoabdominal aortic aneurysm, ruptured abdominal aortic aneurysm and renal artery occlusive disease in patients with preoperative impairment of renal function. Because preservation of kidney function can play an important role in the outcome of these patients, the effects of prostaglandin E1 (PGE1) to prevent ischaemic renal failure were studied in an experimental model. Twenty dogs were exposed to 3 h warm ischaemia by clamping of the supra- and infrarenal aorta and both renal arteries. In 10 dogs PGE1 was given intravenously (100 ng/kg/min) for 15 min before clamping. Ten dogs treated with normal saline served as controls. Glomerular filtration rate, renal plasma flow, plasma creatinine, blood urea nitrogen, urine volume, free water clearance and renovascular resistance were calculated before and after renal ischaemia for both groups. The dogs were followed-up for 2 weeks and radionuclide studies with Tc-99m-MAG3, I-131-OIH and In-113m-DTPA were performed on the third postoperative day to calculate global and split renal clearance, tracer extraction fraction and mean transport time. After renal ischemia 9 dogs of the control group and 3 dogs of the PGE1-group developed acute renal failure (P less than 0.05 due to Fisher's exact text). PGE1 infusion significantly attenuated the postischaemic fall in glomerular filtration rate and renal concentrating ability as well as the postischaemic increase of plasma creatinine and blood urea nitrogen induced by 3 h warm renal ischaemia (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1989

Endothelial protection by defibrotide--a new strategy for treatment of myocardial infarction?

Myocardial ischemia is associated with endothelial injury and an apparently insufficient generation of endothelium-derived vasodilating and platelet and white cell inhibitory mediators, such as prostacyclin (PGI2) and EDRF. This paper reviews some recent findings of our laboratory on cardioprotective effects of defibrotide, a PGI2 stimulating agent, in experimental myocardial ischemia and its possible sites of action in several in vitro assay systems. Defibrotide (32 mg/kg x h) reduced the infarct size by 50% in pigs, subjected to 1 h of coronary artery ligation followed by 3 h of reperfusion. This was associated with significant inhibition of neutrophil activation during the reperfusion period and a two-to threefold increase in cardiocoronary PGI2 generation. In vitro studies on PAF- and calcium ionophore-stimulated human granulocytes confirmed a dose-dependent (10-1000 micrograms/ml) antineutrophil effect of defibrotide (inhibition of lysosomal enzyme release) which was independent of the type of stimulus. Defibrotide (0.1 mg/ml) also inhibited superoxide anion generation from PAF stimulated neutrophils in Langendorff-perfused guinea pig hearts and was equipotent to a specific PAF antagonist (BN 52021). Defibrotide (0.1 mg/ml) did not stimulate PGI2 release from cultured porcine aortic endothelial cells but enhanced PGI2 release four- to fivefold above control if endothelial cells were coincubated with platelets. These data demonstrate a considerable cardioprotective potential of defibrotide which appears to involve endothelial protection from granulocyte-derived noxious compounds and a long-lasting stimulation of PGI2 production.

Animals↗
PubMed1986

Absorption, metabolism and elimination of strophanthus glycosides in man.

In 33 healthy male volunteers, given a single oral and intravenous dose of cymarin (k-strophanthin-alpha), k-strophanthoside (k-strophanthin-gamma) and ouabain (g-strophanthin), enteral absorption and renal excretion of these glycosides and their metabolites were investigated by radioimmunoassay and HPLC. Cymarin was absorbed at 47% of the given dose. After intravenous injection 46% and after oral administration 21% of the given dose, i.e. the total amount as detected by radioimmunoassay which consisted of the unchanged glycoside and its metabolites, were excreted by the kidneys mainly as conjugated metabolites. The half-life of elimination, calculated from the total excreted amount was 13 h (i.v.) and 23 h (p.o.), respectively. k-Strophanthoside was absorbed at 16% of the given dose. After i.v.-injection 73% of the given dose was excreted by the kidneys with a half-life of elimination of 99 h. From this total amount about 70% was excreted as the unchanged drug, the remaining 30% as various metabolites. After oral administration 11% of the given dose were excreted with a half-life of elimination of 22 h. 80% of this amount consisted mainly of conjugated k-strophanthoside and conjugated metabolites as k-strophanthin-beta, cymarin, k-strophanthidin, cymarol and k-strophanthidol. Only 6% was excreted as the unchanged drug. Ouabain was absorbed after oral administration to a minimum of 1.4%. Given intravenously a total renal excretion of 33% of the given dose with a half-life of elimination of 23 h was measured. Of this 80% was unchanged ouabain.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1982

[Imaging adrenergic tumours with 131J-meta-benzylguanidine].

Pheochromocytoma scanning using 131J-meta-benzylguanidine was done in one patient with metastasizing paraganglioma, one patient with multiple endocrine neoplasia type IIb. No activity of tumour tissue could be demonstrated in the patient with metastasizing paraganglioma, whereas the pheochromocytoma could be clearly defined in the patient with multiple endocrine neoplasia type IIa. The female with multiple endocrine neoplasia type IIb showed a suspect space-occupying lesion of the left adrenal using computed tomography. Pheochromocytoma could be excluded by 131J-benzylguanidine scanning, selective estimation of catecholamines in adrenal venous blood as well as the glucagon stimulation and clonidine suppression.

Adrenal Gland Neoplasms↗
PubMed1978

[A method for radio-immunological determination of g-strophanthin (author's transl)].

For the purpose of estimating g-strophanthin radio-immunologically the following steps are described: the preparation of g-strophanthin antigen, the production of antibodies in the rabbit, the presentation of calibration curves, and the possibility of a quantitative determination of heterogenous glycosides. According to Malaprades reaction, g-strophanthin adheres to human albumin. With this antigen thus obtained antibodies are produced in rabbits. For the presentation of calibration curves, the addition of antiserum and g-strophanthin have to be matched in quantity; the calibration curves correspond to mathematical data. An increased sensitivity of the method is possible to attain by reducing the amount of labelled antigen and antiserum. The slight cross-reactivity of antibodies can be used to determine other glycosides when these are incubated labelled with tritium instead of 3H-g-strophanthin.

Animals↗
PubMed1975

The N2 closing volume test in population studies: sources of variation and reproducibility.

Sources of variation in the nitrogen closing volume test and derived measurements were examined in the results of 13 subjects, each of whom performed 3 sequential trials on 2 occasions 30 to 60 minutes apart, on 2 separate days 1 week apart (156 trials in all). Results were examined to evaluate the relative sensitivity of the various measurements for differences between sujbects and, by implication, their potential value in population studies. Using the ratio of signal (between-subject variance) to noise (within-subject variance) as the criterion, the sensitivities of the ratio of closing volume to vital capacity (CV/VC,%) and the ratio of closing capacity to total lung capacity (CC/TLC,%) were comparable; contrary to expectation, sensitivity decreased rather than increased with side-by-side compared to independent tracing analysis. Comparison of various test schedules showed the greatest sensitivity when the mean of 3 measurements was used, with a single measurement of CV/VC,% being only one-third as sensitive, and a single measurement of CC/TLC,% being one-half as sensitive as the mean. In addition, the validity of the measurements of total lung capacity from nitrogen dilution in a single oxygen breath was confirmed by the demonstration of good agreement with helium dilution values.

Adult↗