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Biomedical subjects

R Lehmann

Publications and source records attributed to R Lehmann.

At least 253 records · Page 14Linked to original sources
PubMed1983

Alpha- and beta-adrenoceptors on cultured glial cells.

The action of alpha- and beta-adrenoceptor agonists and antagonists has been studied on the membrane potential of glial cells in cultured rat central nervous system. Noradrenaline and the alpha-agonist phenylephrine caused a depolarization which was reversibly blocked by the alpha-antagonist phentolamine. In contrast, the beta-agonist isoprenaline hyperpolarized the glial membrane. This hyperpolarization was not associated with measurable changes in membrane resistance and was antagonized by the beta-blocker atenolol. These results suggest that the glial depolarization is mediated by activation of alpha-receptors, whereas the hyperpolarization is due to stimulation of beta-receptors. The existence of alpha- and beta-adrenoceptors on glial cells is further supported by autoradiographic studies showing binding of noradrenaline and alpha- and beta-antagonists to astrocytes.

Animals↗
PubMed1983

Evidence of the heterogeneity of the proliferative capacity and for the selection of vascular smooth muscle cells with high proliferative activity in experimental diabetes.

The proliferative activity of cultivated aortic and venous smooth muscle cells (ASMC and VSMC) was estimated by 3H-thymidine autoradiography according to an exact time schedule in primary explant cultures and in the second subcultures of control and streptozotocin diabetic rats. The proliferative activity in both the primary and the subcultures was significantly higher in diabetes than in the control. The proliferative activity of VSMC was significantly lower than that of ASMC and it was not influenced by diabetes. The proliferative activity of subcultures was found--in general--to be lower than that of the primary cultures. "Diabetic" ASMC, however, exhibited exalted proliferative activity. This is considered as evidence for the preexisting heterogeneity of the proliferative capacity and for the selection of ASMC with high proliferative activity as a key mechanism of vascular disease induced by diabetes. The selective advantage of these cells is readily detectable in low density subcultures.

Animals↗
PubMed1982

Evidence for the existence of alpha- and beta-adrenoceptors on cultured glial cells--an electrophysiological study.

The action of adrenergic alpha- and beta-agonists and antagonists has been studied on the membrane potential and resistance of glial cells of cultured rat central nervous system. Noradrenaline and the alpha-adrenoceptor stimulating agents phenylephrine and clonidine (10(-7) to 10(-4)M) depolarized the glial membrane, whereas the beta-agonist isoprenaline caused a hyperpolarization at low concentrations (10(-7) and 10(-6)M). The effects of noradrenaline and phenylephrine were reversibly blocked by the alpha-antagonist phentolamine, whereas those of isoprenaline were antagonized by the beta-blocker atenolol. Atenolol did not affect the depolarization by noradrenaline. The glial depolarization induced by the alpha-agonists was not the consequence of a change in the extracellular K+-concentration unlike that produced by amino acid transmitters. The present results, together with those of biochemical and autoradiographic binding studies, suggest that alpha- and beta-adrenoceptors occur on glial cells and that the glial depolarization is mediated by alpha-receptors, whereas the hyperpolarization is due to activation of beta-receptors.

Animals↗
PubMed1982

[Noninvasive diagnosis of occlusive processes of the brachiocephalic arteries: Doppler sonography compared to ophthalmodynamometry and ophthalmodynamography].

97 patients with suspected cerebrovascular disease were examined using ophthalmodynamometry/ophthalmodynamography and dopplersonography. In 49 of the patients we found haemodynamic changes typical of brachio-cephalic artery occlusion processes. In 36 patients angiography was performed either as a preparation for vascular surgery or for further clarification. Ophthalmodynamometry/ophthalmodynamography examination yielded diagnosis in 87%, dopplersonography and combined use of ophthalmodynamometry/ophthalmodynamography and dopplersonography in 94% of the brachio-cephalic artery occlusion processes.

Adolescent↗
PubMed1980

[Application of a growth model in animal nutrition. 3. Energy requirement for maintenance and performance].

Equations for the calcuation of the energy requirement for maintenance and performance could be derived from a growth model. The energy requirement for performance concerning energy retention is calculated on the basis of the energy content of the animal body. In the model the energy requirement for maintenance for a growing animal is the difference between the total energy requirement and the energy requirement for performance. For the calculation of the energy requirement for maintenance the model is not based on the metabolic live weight.

Animal Nutritional Physiological Phenomena↗
PubMed1980

[Application of a growth model in animal nutrition. 4. Body composition].

The growth development of the body weight and the amounts of protein, water and minerals can be described according to the same function as the live weight of the animal. No generally acceptable equation could be found for the amount of fat. There is a statistically highly significant relation between protein expenditure (Ep) and the growth rate of the liver weight (w): Ep = beta w theta. The protein requirement can be calculated in dependence on the development of the live weight from the growth factors for the live weight and the factors for protein expenditure.

Animal Nutritional Physiological Phenomena↗
PubMed1980

["Low-dose heparin" and other methods to prevent thrombo-embolism in gynaecological surgery (author's transl)].

The effectiveness of low-dose heparin has been compared with other methods of thrombo-embolism prophylaxis, on the basis of 892 gynaecological operations. No case of acute venous thrombosis or lethal pulmonary embolism was established in the Infukoll-M-40 group. No effective prophylaxis against thrombo-embolism was obtainable from acetylsalicylic acid (Micristin). More postoperative bleeding was recorded from the low-dose heparin group. Two far-reaching thromboses and three cases of lethal pulmonary embolism occurred in the wake of low-dose heparin prophylaxis. The most favourable effect, in terms of preventing postoperative leg thrombosis and pulmonary embolism, was recorded from low-molecular dextran (Infukoll M 40). Anaphylactoid reactions, such as bronchospasm, flush, urticaria, and hypotension, were not observed. A therapy standard for gynaecological operations is recommended, with reference being made to the authors' own findings.

Aspirin↗