Search PubMed⌕ Search

Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 523 records · Page 29Linked to original sources
PubMed1982

Structural and functional differences in various divisions of the rabbit colon.

The rabbit colon displays a diversity of form and function along its proximo-distal axis. Morphologically, four regions can be discerned based on macroscopic and microscopic criteria: 1) the initial portion of the colon immediately distal to the cecum (P1), in which wart-like protrusions characterize the surface topography, is 10 cm in length and endowed with three teniae. 2) The adjoining portion of the colon (P2) possesses one tenia, is about 20cm in length and also displays the wart-like protrusions in slightly less prominent form. 3) Fusus coli, a short segment approximately 4 cm in length, is free of teniae, but exhibits longitudinal folds on its inner aspect. Electron microscopically, it shows a paucity of microvilli in direct contrast to the two afore-mentioned regions. These three portions together constitute the proximal colon. 4) The fourth region of the colon, the distal colon, reaches a length of 80-100 cm and shows no obvious second-order enlargements of its surface, displaying scanning electron microscopically ridges in looped configurations. Physiological parameters also showed differences depending on the region of the colon observed. Water content of the ingesta increases slightly during passage of the proximal colon, decreasing in the fucus coli and distal colon. Na concentration was highest in the area P1-P2, decreasing distally. K was low in area P2 and then rose toward the fusus, only to fall again distally. Nitrogen values decrease considerably during passage of P2 but only slightly distally. Transmural electrical potential differences also exhibit a characteristic, discontinuous gradient.

Animals↗
PubMed1982

Characterization of catecholamine-storage organelles in transplantable phaeochromocytoma and adrenal glands of rats.

The properties of the catecholamine-storing organelles from transplantable rat phaeochromocytoma and rat adrenal glands were compared by density gradient centrifugation. It was shown that tumour granules are more heterogeneous and less dense than adrenal granules. Both granule preparations can take up catecholamines and nucleotides by a process driven by an electrochemical proton gradient. Dopamine beta-hydroxylase and glycoprotein III were analysed by immunological techniques. Glycoprotein III was shown to be a specific component of chromaffin granules. Tumour tissue (average weight 700 mg) contains amounts of these antigens comparable to those in 210 adrenals. The biosynthesis of granules in the tumour apparently occurs at a low rate, making turnover studies difficult. The transplantable rat phaeochromocytoma is very useful for studies on the uptake properties and the immunological characteristics of rat catecholamine storage granules because on tumour provides an amount of material that could otherwise be obtained only from a large number of adrenal glands.

Adenosine Triphosphate↗
PubMed1982

[Clinical value of a sensitive TSH-RIA].

Based on a sensitive TSH-RIA (measuring-range 0.2-25 mU/l, 50%-intercept 2 mU/l, coefficients of between-assay-variation 5-10%) and on nearly 1200 cases, it is demonstrated that clinical results can be received by determination of basal serum-TSH alone. Values above 0.5 mU TSH/l indicate positive TRH-tests in a good correlation between increasing basal concentrations and pituitary TSH-reserve. TSH-levels below 0.3 mU/l proceed with negative TRH-tests. In selected healthy subjects, we found all TSH-values between 0.7 and nearly 5 mU/l (means = 1.99). In euthyroid goiters, TSH-levels are normally in the same range, but in nodular goiters, subnormal values were found accumulated. TSH-levels below 0.3 mU/l are helpful to discover non-suppressibility. Hormone-treatment of goiters is successful above all in case of high-normal pretherapeutic TSH-values. "Fine-tuning" of hormone-dosage (goiter-treatment, postoperative prophylaxis, suppression-therapy in thyroid carcinoma) as well as monitoring of thyrotoxicosis-treatment is recommended to be performed by means of basal TSH-determination. In pituitary disorders, thyroid hormone-treatment seems to be necessary only at TSH-levels below 0.5 mU/l. Combination of basal TSH and total T-3 is economical and describes nearly all functional situations in diagnosis and treatment of thyroid diseases.

Goiter↗
PubMed1982

[Serum cholesterol and liver deiodase activity in rats of different body composition after low or high fat diet. Effect of a feeding change in fat-rich to fat-poor diet and the reverse or of an iodine deficient diet].

Male Wistar rats with an average age of 28 weeks received diets high (HFD: 50% fat) or low (LFD: 3% fat) in fat content. Rats were restricted on iodine intake by feeding pure diets without iodine addition. The relative degree of iodine shortage of rats was estimated by 131I-uptake. PB131I and ETR. Serum cholesterol, whole body lipid content and liver deiodinase activity of LFD (control)- and HFD-rats were analyzed. A change of diet feeding from high to low fat content and vice versa took place to discriminate the effect of diet fat from body fat content of rats on serum cholesterol and deiodinase activity. HFD fed rats with high body fat content showed at iodine restriction the same serum cholesterol concentration as relative lean LFD-animals. Post feeding change from diet rich to poor on fat and vice versa at 4 weeks the obese animals have lost body fat only 10-20% at calorie restriction and exhibit higher serum cholesterol levels and equal liver deiodinase activity as lean, now fat rich fed control animals. Heavy HFD-rats fed on fat rich diet for 22 weeks have approximately two times higher liver lipid content as light LFD-animals. Because liver lipid content and deiodinase activity between light LFD- and heavy HFD-rats before and after change of diet feeding are equal, a relation between liver lipid content and enzyme activity is discussed.

Animals↗
PubMed1982

[Passive smoking].

One of the most important sources of indoor air pollution is tobacco smoke. It was the aim of the reported laboratory and field experiments to quantitatively determine both indoor air pollution by tobacco smoke and the acute health effects on man associated herewith. The results showed that of 472 workers who were interviewed, about 30% were complaining about the smoke at their working place, whereas 40% felt annoyed by the smoke and about 25% indicated eye irritation. The subjectively and objectively observed acute irritation effects and annoyances generally increase with an increasing smoke concentration. Healthy persons are expected to support irritation and annoyance from tobacco smoke concentrations which correspond to a tobacco-derived carbon monoxide concentrations of 1 - 2 ppm. Measures to protect passive smokers are recommended up from 1 ppm tobacco-derived carbon monoxide and are necessary up from 2 ppm. Calculating ventilation rates shows that at a constant smoke production of 1 cigarette/h, a ventilation with fresh air of 33 m3/h is necessary to maintain the upper limit of 2 ppm CO. This corresponds to 33 m3 of air per person and hour in a room occupied by 10 persons, and to 23 m3 of air per person and hour in a room with 100 persons.

Adult↗