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Biomedical subjects

B Krauss

Publications and source records attributed to B Krauss.

48 records · Page 3Linked to original sources
PubMed1979

Enzyme kinetic studies and inhibition by oligopeptides of LH-RH degradation in rat hypothalamus and pituitary.

The enzyme kinetic parameters of the degradation of luteinizing hormone-releasing hormone (LH-RH) and L-cystine-bis-(4-nitroanilide) (Cys-NA) by rat hypothalamic (HYP) and pituitary (PIT) extracts and the effect of various oligopeptides on the rate of LH-RH inactivation were investigated in vitro. The 105,000 x g supernatant of 1 rat HYP inactivated 57 microgram LH-RH during a 30 min incubation (Km = 12.4 microM, V max = 2.33 microgram LH-RH/mg protein/min), and of one rat anterior PIT, 48 microgram LH-RH during 30 min of incubation (Km = 12.2 microM, V max = 8.0 microgram LH-RH/mg protein/min). The synthetic substrate Cys-NA competitively inhibited LH-RH degradation with a Ki of 8.5 microM in the HYP and 6 microM in the PIT enzyme preparation. Vice versa, LH-RH also competitively inhibited the cleavage of Cys-NA with inhibition constants of 14 microM (HYP) and 15 microM (PIT) indicating that the 2 substrates are probably cleaved by the same enzyme. The most effective inhibitors of LH-RH degradation were found to be angiotensin-related peptides, neurotensin, bradykinin, and bacitracin. A relatively weak effect was obtained with oxytocin, enkephalin and puromycin. It is concluded that endogenous oligopeptides such as angiotensins, neurotensin, bradykinin, etc., may possibly influence H-RH degradation in the PIT and the HYP. The synthetic substrate Cys-NA may be an appropriate substrate for measuring the activity of an LH-RH-degrading peptidase, which therefore could be classified as arylamidase.

Aminopeptidases↗
PubMed1979

Inhibitory control of the pituitary LH secretion by LH-RH in male rats.

Luteinizing hormone-releasing hormone (LH-RH) was administered to prepubertal male rats (intact, castrate or castrate-adrenalectomized, 60 g body weight) for 28 days (1 microgram LH-RH/day, s.c.), at a 10-fold physiological dose, as compared to the minimal FSH-releasing dose of 100 ng/rat s.c. In intact rats, serum LH and weight of androgen-dependent organs (vented prostate, seminal vesicles) were reduced after 14 days of treatment. In castrate rats, the postcastration rise in serum LH was abolished by treatment. Pituitary LH content, FSH secretion and prolactin secretion were not suppressed. Hypothalamic LH-RH was increased at 14 and 21 days. In castrate adrenalectomized male rats, LH secretion was also suppressed by 1 microgram LH-RH s.c. x 28 days. The hypothalamic LH-RH content did not increase. The pituitary LH-RH receptor level was not down-regulated after 14 days treatment either in intact or castrate male rats. Pituitary inhibition (LH release) in rats by a supraphysiological dose of LH-RH given for 28 days indicates that the optimal regime for chronic treatment has to be determined by monitoring LH release at regular intervals. Direct pituitary inhibition by LH-RH may explain some of the unexpected antifertility effects observed with high doses of LH-RH.

Adrenal Glands↗
PubMed1977

Performance differences between addicts and non-addicts.

Methadone addicts and non-addict controls were tested before and after receiving up to 10 mg of methadone on simple visual reaction time tests and on a vigilance type visual attention test. Addicts were faster than controls on pre-drug testing, although there were no pre-drug differences between groups on the attention task. Addicts maintained faster reaction times than controls even when money was offered as an incentive for speed. Additional methadone did not affect addict performance on any of the tasks. Methadone slowed control reaction times in a dose-related fashion. No significant attention decrements were seen after methadone in controls. Visual reaction time differences between addicts and controls cannot be attributed to group differences in motivation or ability to attend. Slowing of reaction time with acute dose of methadone in controls cannot be attributed to the effect of the drug on attention. An hypothesized drug-induced decrease in visual sensitivity with acute dose in controls and a drug-induced increase in visual sensitivity with chronic dose in addicts can account for the presented data.

Adult↗
PubMed1975

[Liver diseases in diabetes mellitus].

In a number of 3,554 clinically manifest diabetics who were admitted for the treatment of metabolism or other diseases from 1967 to 1974 12.1 per cent of hepatopathies were found. In men the incidence was 15.2 per cent, in women 10.7 per cent. Among these the fatty degeneration of the liver (28.8 per cent) and the cirrhosis (17.4 per cent) were most frequent. Referred to the entirety the result was an incidence of cirrhosis of 2.1 per cent. The confirmation of the diagnosis is performed by biopsy and endoscopy in 92 per cent. In 60 per cent of the examined persons the diagnosis was unknown before admission. There was no correlation to the duration of the diabetes. In the number of patients there appeared above all persons older than 50 to 60 years. The following concomitant diseases occurred: hypertension (33 per cent), coronary diseases (32 per cent), pyelonephritis (17 per cent) and adiposity (13 per cent).

Biopsy↗
PubMedDate not supplied

[Nuclear magnetic resonance tomography in destructive changes of the spine].

Correct treatment of destructive lesions in the vertebral column requires exact radiological evaluation with the traditional techniques of plain films, computed tomography and radionuclide scanning. With the development of magnetic resonance imaging the possibility of visualizing pathological changes of the bone marrow became apparent. To prove the value of MRJ in detecting destructive lesions of the spine 29 patients were investigated using plain radiographs, computertomographies, radionuclide scanning and MRJ. The findings were correlated to the intraoperative aspect of the lesion and the results of the histological investigation in 18 cases. MRJ showed to be a very sensitive manner of detecting bone marrow changes of different kind. Indeed characteristic changes in signal intensity were not to be observed in pathological lesions of inflammatory or tumorous genesis. So the distinction is based on morphological criterias.

Adolescent↗
PubMedDate not supplied

[Kidney function and prostatic disease in the aged].

The pathophysiology of subvesical urinary obstruction is not solely restricted to the distal urinary tract by extension to proximal areas via reflux more systemic significance is achieved. "Each patient with a chronical distended bladder is at grave's edge" (Wildbolz). After release of increased intravesical pressure, rapid return to the normal pathomorphological conditions of the urinary organs is always rather surprising. However, once the renal parenchyma is damaged, morphological regeneration is impossible, resulting in so called hypoplastic renal atrophy. Thus, the pathophysiological significance of the prostate for bilateral obstructive nephropathy is easily understood.

Aged↗