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Biomedical subjects

W Lehmann

Publications and source records attributed to W Lehmann.

At least 19 recordsLinked to original sources
PubMed1991

Bombesin, vasopressin, and endothelin rapidly stimulate tyrosine phosphorylation in intact Swiss 3T3 cells.

The mitogenic neuropeptides bombesin and vasopressin markedly increased tyrosine and serine phosphorylation of multiple substrates in quiescent Swiss 3T3 fibroblasts, including two major bands of Mr 90,000 and 115,000. Tyrosine phosphorylation of these proteins was increased as judged by immunoprecipitation of 32Pi-labeled cells and immunoblotting of unlabeled cells with monoclonal antiphosphotyrosine antibodies, elution with phenyl phosphate, and phospho amino acid analysis. Phosphotyrosyl proteins generated by bombesin and vasopressin did not correspond either by apparent molecular weight or by immunological and biochemical criteria to several known tyrosine kinase substrates, including phospholipase C gamma, the microtubule-associated protein 2 kinase, GTPase-activating protein, or phosphatidylinositol kinase. The effect was rapid (within seconds), concentration dependent, and inhibited by specific receptor antagonists for both bombesin and vasopressin. The endothelin-related peptide, vasoactive intestinal contractor, also elicited a rapid and concentration-dependent tyrosine/serine phosphorylation of a similar set of substrates. These results demonstrate that neuropeptides, acting through receptors linked to GTP-binding proteins, stimulate tyrosine phosphorylation of a common set of substrates in quiescent Swiss 3T3 cells and suggest the existence of an additional signal transduction pathway in neuropeptide-induced mitogenesis.

1-Phosphatidylinositol 4-Kinase↗
PubMed1991

Methylene blue attenuates vasodilation and enhances vasoconstriction in response to endothelin-1 in the pig nasal mucosa.

In thiopentone anaesthetized pigs (n = 10), simultaneous recordings of the vasomotor response to local intra-arterial infusion of endothelin-1 and -3 were performed in three different vascular compartments of the nasal mucosa. Sphenopalatine artery blood flow (reflecting nasal blood flow), nasal cavity volume (representing blood content in capacitance vessels) and laser Doppler flowmeter signal (reflecting superficial mucosal blood flow) increased in response to low doses (4 x 10(-9) to 4 x 10(-8) moles) of endothelin-1. In contrast, marked vasoconstriction (up to 50% of arterial blood flow reduction) occurred upon higher doses (4 x 10(-7) to 4 x 10(-6) moles). Endothelin-3 (4 x 10(-9) to 4 x 10(-6) moles) evoked at the highest dose a long-lasting increase of systemic arterial blood pressure resulting in a 22 +/- 4% increase in nasal vascular resistance. After local intra-arterial pretreatment with methylene blue (4 x 10(-4) mol), the vasodilatory responses to low doses of endothelin-1 were abolished for the three vascular parameters studied, whereas the vasoconstrictor responses in resistance and capacitance vessels evoked by higher doses of endothelin-1 were increased. In contrast, the laser Doppler flowmeter signal reduction in response to endothelin-1 was markedly attenuated. The vasodilatatory effect of substance P was abolished after methylene blue probably due to interference with effects of endothelium dependent relaxing factor (EDRF). These observations suggest that in the pig nasal mucosa in vivo, exogenous endothelin-1 induces a dose-dependent reduction of blood flow in resistance and capacitance vessels and in superficial mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

A rare electrophoretic enzyme variant of serum alkaline phosphatase in a group of Icelanders.

An electrophoretic isoenzyme variant of serum alkaline phosphatase was found in 10 out of 343 subjects belonging to an Icelandic population in Husavik and the Husavik region. 9 of the variant-positive subjects were women. The enzyme variant differs from normal isoenzymes in electrophoretic mobility, substrate specificity, and response to inhibitors. It could be demonstrated that nine of the subjects with the enzyme variant were related with each other.

Adult↗
PubMed1979

[Filling of the Circle of Willis in carotid angiography using halothane anesthesia].

A comparative study of 150 carotid angiographies carried out under local anaesthesia and the same number under halothane anaesthesia did not show any great deviation from the well-known filling rates of the counter-lateral carotid region and the ipsilateral A. cerebri posterior nor any striking differences in the two methods of anaesthesia which could convince of a favourable influence of halothane on the demonstration of the vessels. The causative factors of the filling of adjacent vascularisation regions can certainly only be explained from the complex co-action of physiological and any external factors in cerebral angiography.

Adolescent↗
PubMed1978

[Lymphatic metastasis of the neck. Pluridisciplinary approach--surgery].

The main features of tumoral pathology in the neck are metastatic lymph nodes of carcinomas having their origin in the upper respiratory and digestive tracts. Their prognosis will depend directly on the diagnostic approach and correct treatment. The place and modalities of surgery in the treatment of head and neck metastatic lymph nodes are discussed.

Biopsy↗
PubMed1978

[Kinetics of citric acid production in Candida lipolytica].

The kinetics of citrate and isocitrate accumulation by Candida lipolytica has been studied, with special emphasis of the carbon sources glucose and n-alkanes and the shifts from one carbon source to the other. The accumulation of the citric acids starts with the beginning of ideophase. Trophophase and ideophase behaviour is in parts different. Ideophase behaviour may be influenced by exogenic factors during growth. From the course of the curves for the citric acids two phases can be distinguished: The specific production rate of the first phase is higher than in the second phase (pi1 approximately 0.19 h-1; pi2 approximately 0.14 h-1). The influence of the carbon source on the course of the curves and the numeric value for the specific production rate is negligible. Alcane grown cells accumulate citric acids from added glucose and left-over n-alcanes simultaneously. When both substrates are added from the beginning only glucose is taken up for growth, for citric acid production both substances are utilized simultaneously. Glucose grown cells do not utilize alcanes for production of citric acids. Citric acids are accumulated only as long as glucose is available. Alcane uptake starts after addition of a nitrogen source.

Aerobiosis↗
PubMed1978

The effect of oxazepam on sleep in normal human volunteers.

The effects of 25 mg of oxazepam, a benzodiazepine with a short half-life and no active metabolites, were compared with placebo in two healthy volunteers in a single-blind polygraphically recorded sleep study. The experiment lasted for 24 nights and recordings were made for 11 nights. It was found that 25 mg oxazepam induced sleep faster than placebo, and that the subjects awoke less often during the treatment period. The total amount of REM-sleep was not affected. However, REM-sleep was shortened during the first part of the night and extended during the latter part of the night. Slow-wave sleep diminished differently in the two subjects, possibly due to interindividual differences in the rate of elimination of oxazepam. The effect on blood pressure was small, and the normal physiological difference between bedtime and morning blood pressure was preserved.

Adult↗
PubMed1978

[On secondary operations following submucous septum resection (author's transl)].

The submucous resection of septum by Killian is not appropriate as a primary correcting treatment, especially in case of traumatical septum deformities. Due do the loss of cartilage often form and function of the nose deteriorates in a typical way. These complaints demand an operative correction under complicated circumstances. Based on the patient clietele of the Univ.-HNO-Klinik Erlangen it is demonstrated how secondary operations with the special technique of displacement of the remaining cartilage a satisfying result finally can be achieved.

Congenital Abnormalities↗
PubMed1977

Raman spectroscopic investigation of the interaction of gramicidin A with dipalmitoyl phosphatidylcholine liposomes.

The interaction of gramicidin A with dipalmitoyl phosphatidylcholine liposomes is investigated by Laser-Raman spectroscopy. As revealed by the methylene C-H stretching mode the phase transition of the hydrocarbon chains near 40 degree C is eliminated in the presence of gramicidin A. Liposomes prepared from a mixture of lecithin and cholesterol seem to be unaffected by gramicidin A and show only the normal broadened phase transition.

Binding Sites↗
PubMed1977

Chalone-like inhibition of Ehrlich ascites cell proliferation in vitro by an ultrafiltrate obtained from the ascitic fluid.

An aqueous ultrafiltrate (10 000-50 000 dalton) prepared from the cell-free ascitic fluid of mice bearing Ehrlich ascites tumour (EAT) in the plateau phase of growth (12-16 days after transplantation) was investigated with regard to its inhibitory effects on the proliferation of EAT cells in a 24-hr suspension culture. The following results were obtained: (1) The in vitro proliferation of cells obtained from the plateau phase of in vivo growth was reversibly inhibited. (2) The dose-response curves show a plateau with a maximum inhibition of about 50%, which suggests that not all cells can be affected. (3) Young cells (4-6 days after transplantation) were not inhibited. (4) Preincubation of plateau phase cells in the culture medium before treatment abolishes the inhibitory effect of the ultrafiltrate. This effect of preincubation is dependent on time and serum concentration. It provides the possibility to differentiate between true "chalone-like" and cytotoxic effects. (5) the inhibitory properties of the ultrafiltrate are destroyed by heating or trypsin treatment. (6) Extracts prepared in the same way from ascitic fluid of mice bearing lymphocytic leukemia L1210 do not inhibit the proliferation of EAT cells. Corresponding extracts from ascitic fluid of mice bearing myelocytic leukemia YM were found to be inhibitory; however, the inhibitory effect was also found on preincubated cells and is therefore considered to be due to an unspecific cytotoxicity. In conclusion, evidence was obtained for a factor from the ascitic fluid of mice bearing EAT, which prevents EAT cells from entering the proliferating state.

Animals↗