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Biomedical subjects

S Graf

Publications and source records attributed to S Graf.

63 records · Page 4Linked to original sources
PubMed1979

Inhibition of human intestinal alpha-glucosidehydrolases by a new complex oligosaccharide.

The effect of a new complex oligosaccharide (Bay g 5421) of microbial origin on human intestinal alpha-glucosidehydrolase activity was tested in mucosal homogenate from human small bowel biopsy specimens. The alpha-glucosidehydrolase inhibitor (alpha-GHI) exerted a potent inhibitory effect on glucoamylase, sucrase, and maltase, was minimally effective on isomaltase, and did not affect trehalase and lactase activity. Kinetic analysis revealed a fully competitive type of inhibition with a Ki of 1.3 x 10(-6) M; thus the inhibitor had a 15,000-fold higher affinity to the enzyme sucrase than its natural substrate sucrose. The new compound may prove to be useful in the study of carbohydrate maldigestion and malabsorption and may possibly be of therapeutic benefit in diabetes and obesity.

Adult↗
PubMed1979

The short metyrapone test: comparison of the plasma ACTH response to metyrapone and insulin-induced hypoglycaemia.

Plasma ACTH levels in response to metyrapone and insulin hypoglycaemia were compared in subjects with normal pituitary-adrenal function. After a single dose of 2 g of metyrapone given with a snack at midnight, the ACTH level was 468 ng/l +/- 66 )SEM) at 07.30 h the next morning (mean increment approximately nine fold over normal morning values). After insulin-hypoglycaemia the peak ACTH level was 369 ng/l +/- 31 (SEM). Peak ACTH levels greater than 200 ng/l were achieved in twenty of twenty-one (95%) subjects after metyrapone and twenty of twenty-four (83%) after insulin. No major side effects were noted after metyrapone. It is concluded that the short single-dose metyrapone test produces at least as strong and consistent a stimulus to ACTH release as the standard insulin-hypoglycaemia test in normal subjects. A direct assay of ACTH avoids misinterpretations which are inherent in a judgement based on compound S increase only. The short test has significant practical advantages over the classical metyrapone test, and provides a convenient and sensitive method of assessing the negative feedback ACTH control mechanism. It may be particularly useful in detecting minor degrees of pituitary suppression. The value of this test in clinical practice for the investigation of patients with hypothalamic-pituitary diseases in comparison to the classical tests of ACTH stimulation has yet to be demonstrated.

Adolescent↗
PubMed1978

[Binding of antacids to bile acids (author's transl)].

The bile acid binding capacity of various liquid antacids and of colestyramin were compared. Aluminium hydroxide containing antacids showed the highest binding capacity. This seems to be of importance also in therapeutic doses for treatment of chologenic diarrhoea, vagotomy diarrhoea and gastric ulcer.

Antacids↗
PubMedDate not supplied

Correlation of 3D MRI and clinical findings in the patients with sensorineural hearing loss and/or vertigo.

The aim of the study was to correlate clinical and magnetic resonance imaging (MRI) (3D CISS and MP-RANGE) findings in patients with sensorineural hearing loss (SNHL) and/or vertigo. We found a high correlation of MRI and symptoms (17 out of 18 patients, 13 out of 13, respectively) concerning detectability of tumors and acute labyrinthitis. In the case of labyrinthine fibrosis, the correlation between clinical and MRI findings was lower. In conclusion, high-resolution MRI is very suitable in patients with SNHL or vertigo caused by tumors or acute labyrinthitis.

Adolescent↗
PubMedDate not supplied

Functional assessment of coronary arteries by poststenotic intravascular Doppler ultrasound.

This study sought to delineate the impact of the rate pressure product on intraluminal Doppler velocity measurements and to determine the relation between poststenotic vasodilator reserve and percent luminal obstruction in coronary vessels. Twenty patients with single-vessel coronary disease were studied prior to coronary angioplasty and at follow-up 6 months later. Intracoronary velocity reserve after administration of adenosine was measured distal to the stenosis with a Doppler-tipped guide wire and was compared to quantitative coronary angiography and adenosine myocardial perfusion scintigraphy. The rate pressure product was confirmed as significant covariate (ANCOVA, p < 0.005) of intracoronary Doppler reserve. When normalized to rate pressure product, poststenotic Doppler velocity reserve in stenosed arteries was significantly lower than in patent arteries as classified by quantitative coronary angiography (1.7 +/- 0.6 vs. 2.9 +/- 0.5, p < 0.001) and perfusion scintigraphy (1.5 +/- 0.4 vs. 2.8 +/- 0.5, p < 0.001). Normalized Doppler velocity reserve showed a nonlinear but highly significant relation to percent area stenosis [y = 3.0.(1 - exp[0.081 (x - 100)]), p < 0.001]. When normalized Doppler velocity reserve was less than 2.0, coronary disease was identified with 95% specificity and 94% sensitivity in comparison to perfusion scintigraphy. Thus, in coronary arteries poststenotic Doppler reserve and percent area stenosis show a significant nonlinear relation. Doppler velocity reserve when normalized to rate pressure product can be used to characterize the hemodynamic impact of coronary obstructions.

Adenosine↗