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Biomedical subjects

K Schwarz

Publications and source records attributed to K Schwarz.

17 recordsLinked to original sources
PubMed1979

Role of the pituitary gland in experimental hormonal induction and prevention of benign prostatic hyperplasia in the dog.

The antiandrogen, cyproterone acetate (CPA), prevents development of prostatic hyperplasia, induced in castrated dogs by a 6 month-treatment with 5 alpha-androstane-3 alpha, 17 beta-diol (A)alone or in combination with 17 beta-oestradiol (E2). The immunoperoxidase technique was used to study functional cell types in the pars distalis of the pituitary gland and to detect growth hormone (GH) and prolactin (PRL) target sites in the prostate gland. Homologous radioimmunoassays for estimation of serum canine GH and PRL concentrations were also performed. Treatment with the combinations A + E2 and A + E2 + CPA resulted in morphological indications of stimulated GH and PRL cells and depressed gonadotrophs. This correlates well with an increase in PRL-dependent staining in glandular epithelium and fibromuscular tissue of the prostate gland. However, basal serum PRL and GH levels were not significantly affected. Treatment with A and A + E2 stimulated, while additional treatment with CPA clearly suppressed adrenocorticotrophin/melanotrophin (ACTH/MSH) cells. These findings indicate that an endocrine imbalance in hypothalamic-pituitary-adrenal function may be involved in induction and prevention of prostatic hyperplasia in the dog.

Androstane-3,17-diol↗
PubMed1978

Epidemiology of cancers: I. Cancerous diseases of the large bowel.

A pilot study of cancerous diseases of the large bowel in Canterbury is described. The experience of 346 patients derived from the Cancer Registry for 1970-72 is presented. The feasibility of the method is demonstrated with the identification of guidelines for future work. The preliminary results suggest some special features in New Zealand. While demographic characteristics do not appear to help in defining persons at high risk from cancerous diseases of the large bowel, nevertheless other features of the natural history of this disorder indicate that it might be feasible to define high risk profiles.

Adult↗
PubMed1978

Role of cyclic AMP in the regulation of renin release from the isolated perfused rat kidney.

The role of cyclic AMP in the regulation of renin release (RR) was studied in isolated rat kidneys, which were perfused at constant pressure in a single-pass system with a modified Krebs-henseleit solution. Isoproterenol (IP) (2 x 10(-9) to 2 x 10(-6) M) and 3-isobutyl-1-methyl-xanthine (IBMX) (4 x 10(-7) to 7 x 10(-5) M) induced a dose-dependent increase of renal perfusate flow, glomerular filtration rate and urinary sodium excretion. RR was stimulated up to 10-fold above control values within 5 min. At the lowest concentrations IP stimulated RR, but did not affect renal haemodynamics. When IP and IBMX were administered concomitantly, a supraadditive stimulation of RR was observed. Dibutyryl-cAMP (db-cAMP) and 8-Br-cGMP (10(-6) to 10(-4) M) produced a similar dose-dependent vasodilation and natriuresis, but differed in their action on RR. Within 15 min after the start of the infusion, db-cAMP increased RR up to 4-fold, whereas 8-Br-cGMP was without an effect. These results suggest that IP, IBMX and db-cAMP stimulated RR by increasing the concentrations of cAMP in the epitheloid cells and independently of changes in renal haemodynamics and sodium excretion.

1-Methyl-3-isobutylxanthine↗
PubMed1978

[Influence of population growth on national health care (author's transl)].

In the Federal Republic of Germany a decline of population is expected, because fertility is very low. This article deals with the implications of this trend for the health system. On the basis of population models and population forcasts the author comes to the conclusion that in the long run the burden of health costs will not become lower but higher, because of the growing proportion of old people. Nevertheless it is supposed that the influence of other factors than demographic ones may be greater.

Adolescent↗
PubMed1977

Silicon, fibre, and atherosclerosis.

A logical argument can be made for the hypothesis that lack of silicon may be an important aetiological factor in atherosclerosis. As silicic acid or its derivatives, silicon is essential for growth. It is found mainly in connective tissue, where it functions as a cross-linking agent. Unusually high amounts of bound silicon are present in the arterial wall, especially in the intima. Various kinds of dietary fibre have been reported to be effective in preventing experimental models of atherosclerosis, reducing cholesterol and blood-lipid levels, and binding bile acids in vitro. Exceptionally large amounts of silicon (1000 to 25 000 p.p.m.) were found in fibre products of greatly varying origin and chemical composition which were active in these tests. Inactive materials, such as different types of purified cellulose, contained only negligible quantities of the element. It is concluded that silicate-silicon may be the active agent in dietary fibre which affects the development of atherosclerosis. Two out of three samples of bran also had relatively low levels, which could explain why bran does not lower serum-cholesterol. The fact that atherosclerosis has a low incidence in less developed countries may be related to the availability of dietary silicon. Two instances are presented where silicon is reduced by industrial treatment: white flour and refined soy products were much lower in silicon than--their respective crude natural products. The chemical nature of silicon in different types of fibre is not known. It could exist as orthosilic acid, polymeric silicic acid, colloidal silica (opal), dense silica concentrations, or in the form of organically bound derivatives of silicic acid (silanolates). Possible mechanisms of action are discussed.

Anticholesteremic Agents↗
PubMed1977

A new integrated couse in preventive and coummunity medicine.

An integrated course in Preventive and Community Medicine was introduced at the Christchurch Clinical School, New Zealand in 1974. Details of the fourth and fifth clinical years as well as the elective studies in the trainee intern (sixth) year are presented. The implications of the topic studies, rotating attachments, preventive medical examinations, preventive medical ward rounds, problem-orientated record studies, simulated disabilities and Clinico-Pathological Conferences are discussed. Some preliminary conclusions are drawn from the evaluation of this course.

Community Medicine↗
PubMed1976

[Radiotherapy of precancerous lesions and carcinoma of the head (author's transl)].

On the basis of results and check-ups gained at the clinic of Zurich, it can be demonstrated, once more, that radiotherapy of precancerous lesions and tumors, even critically considered, is still a very valuable and safe method of treatment with lasting success in 90 to 99% of the cases. At the same time this method safeguards the essential functions, even in the case of particularly difficult areas.

Ear Neoplasms↗
PubMed1975

Biological potency of organic selenium compounds: VI. Aliphatic seleninic acids and carboxyselenic acids.

Straight-chain aliphatic seleninic acids, CH3-(CH2)n-SeOOH, with chain lengths from C4 to C17, a few dibasic acids of moderate chain length having seleninic acid groups on both ends of the molecule, HOOSe-(CH2)n-SeOOH, and a series of carbosyseleninic acids, HOOC-R-SeOOH, comprising chain lengths from C3 to C13 and several branched chains with 5 to 7 carbon atoms were tested for potency in the prevention of dietary liver necrosis in the rat. Alkylseleninic acids showed uniformly low activities, ranging from 18% to 56% of that of selenite selenium which served as a standard. There were no discernible trends or regularities with increasing chain lengths, in c-ntrast to other series of alkylselenium compounds. It is therefore unlikely that alkylseleninic acids are normal oxidation products of dialkyl mono- or diselenides in the organism. Compounds with seleninic acid groups at both ends of the chain were practically inactive. Carboxyseleninic acids carrying a carboxyl group distal to the seleninic acid group, on the other hand, were highly effective. A maximum of potency occurred at chain lengths C3 and C4, followed by a sharp decline between C4 and C6. A second maximum of activity occurred at C8. There was no alternating effect. This structure/activity pattern is analogous to that of the diselenodicarboxylic acids. However, the lower carboxyseleninic acids were, per atom of selenium, twice as active as the corresponding diseleno-dicarboxylic acids, of which the higher members were less potent. It is inferred that carboxyseleninic acids may be metabolically related to diseleno-dicarboxylic acids and that C3 and C4 carboxyseleninic acids may play a physiological role.

Animals↗