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R Zimmermann

Publications and source records attributed to R Zimmermann.

At least 523 records · Page 29Linked to original sources
PubMed1978

Simultaneous determination of the total number of aquatic bacteria and the number thereof involved in respiration.

The electron transport system of respiring organisms reduces 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to INT-formazan. Respiring bacteria deposit accumulated INT-formazan intracellularly as dark red spots. Corresponding to electron transport system activity, these deposits attain a size and a degree of optical density which allows them to be examined by light microscopy. If polycarbonate filters and epifluorescence microscopy are applied to analyze an INT-treated water sample, it is possible to differentiate between respiring and apparently nonrespiring bacteria. This differentiation, which permits determinations of the total number of bacteria and the proportion thereof involved in respiration, is realized directly within one and the same microscopic image. Initial applications of the present method for hydrobiological purposes showed that the proportion of respiring aquatic bacteria ranged between 6 to 12% (samples taken from coastal areas of the Baltic Sea) and 5 to 36% (samples taken from freshwater lakes and ponds). Cells of 1.6 to 2.4 micrometer (freshwater) and 0.4 micrometer (Baltic Sea) account for the highest proportion of respiring bacteria.

Bacteria↗
PubMed1978

[Reactions vis-a-vis the disabled. Critical comments on G. H. Neumann's article: prejudices and negative attitudes towards the disabled--their origin and methods of elimination from the viewpoint: of behavioural science and biology (author's transl)].

Neumann's opinion that prejudices towards the disabled are decisively determined by inborn reactions, i.e., the reaction towards outsiders and the fear reaction towards strangers, is put to question. Ethological and ethnological research results demonstrate that the studies of human and animal behaviour towards the "disabled" are still in an elementary stage and that hitherto available results only permit the conclusion that animals as well as human beings display a very complex and differentiated behaviour vis-a-vis the disabled. In connection with human beings this complexity is seen as evidence of the outstanding significance of societal factors--in their broadest sense--for the formation of prejudices towards the disabled. The necessity of a goal-oriented elimination of these prejudices is stressed. Furthermore, attention is drawn to terminological problems and the difficulties or comparisons between human beings and animals.

Animals↗
PubMed1978

[Effect of halofenate on triglyceride and uric acid levels, coagulation and platelet behaviour in patients with hyperlipoproteinemia type IV and hyperuricemia (author's transl)].

From experimental work, an influence of a drug with hypolipidemic and hypouricemic acition on blood coagulability and platelet function may be expected. Consequently, if these effects were demonstrable in man the drug could be assumed to reduce the tendency to develop thrombosis and atherosclerosis in patients with hyperlipidemia and hyperuricemia. In the study reported, the effect of 2-acetamidoethyl-(p-chlorophenyl)-(m-trifluoro-methylphenoxy)-acetate (halofenate) was investigated in 14 patients suffering from hyperlipoproteinemia type IV and hyperuricemia. Platelet aggregation and adhesiveness, plasma levels of triglycerides, cholesterol, uric acid, and clotting factors were regularly examined during a three-month double blind trial. While uric acid and triglyceride levels decreased, no influence of the drug treatment could be observed on platelet function and blood coagulability by the laboratory methods used.

Adult↗
PubMed1978

[Antimalarial 6-aminoquinolines. XI. 2-, 3-, and 4-alkyl-, aryl-, and arylalkyl derivatives (author's transl)].

23 derivatives 17a--z of 6-(4-diethylamino-1-methylbutylamino)-5,8-dimethoxyquinoline (1a) were synthesized with the aim of studying the influence of an increased lipophilicity on the biological activity. 17a--z are active against P. vinckei (mouse), but none of these derivatives is superior to the 2,4-dimethyl derivative 1d. Flat molecules (e.g. 17k and 17e) and their bulky hydrogenated derivatives (17I and 17f) show a comparable activity. This indicates that a flat structure is not essential for the activity of the 6-aminoquinolines.

Aminoquinolines↗
PubMed1978

[Hair casts].

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1977

Mössbauer studies of cytochrome c' from Rhodospirillum rubrum.

Cytochrome c' from Rhodospirillum rubrum has been investigated in the ferric form with Mössbauer and EPR spectroscopy. In the pH range from 6 to 9.5, three species are observed which belong to two pH-dependent equilibria with pK values near 6 and 8.5. The pK = 6 transition is resolved only with high-field Mössbauer spectroscopy. For the three species we have determined the zero-field splitting parameters and the hyperfine coupling constants. The data were fitted to a spin Hamiltonian which takes into account a weak mixing of excited S = 3/2 states into the sextet ground manifold. The low temperature spectra clearly show that the quadruple coupling constant deltaEQ is positive for ferricytochrome c' and thus in accord with all other high-spin ferric heme proteins.

Cytochrome c Group↗
PubMed1977

[Carbenicillin induced disturbance of platelet function: a study in patients with normal renal function (author's transl)].

After therapeutic doses of carbenicillin (3X10 g/24 h) prolongation of bleeding time, measured according to Ivy, was observed (median time prior to therapy 4 min 08 s-4 min 18 s; 24 h after therapy 15-20 min; 72 h after therapy greater than 30 min) in 5 patients with normal renal function and 2 patients with slight impairment of renal function (Ccr60-70 mlX1.73 m(2)). Prolongation of bleeding time was observed at serum concentrations between 13 and 180 microgram/carbenicillin/ml. After carbenicillin was withdrawn, prolongation of bleeding time was demonstrable for 4 days, i.v. even after the drug had been eliminated completely by urinary excretion. Higher doses of carbenicillin caused more severe disturbances of platelet function. The finding of prolonged bleeding time after carbenicillin may have clinical relevance (e.g. interaction with other anticoagulants, p.o. wound bleeding, gastro-intestinal hemorrhage, thrombopenia).

Adult↗
PubMed1977

[Oral anticoagulants and platelet function in hypolipemic therapy using a new clofibrate analog (BM 15.075) (author's transl)].

When testing the effect of a new clofibrate analogue (BM 15.075) on oral anticoagulation and blood clotting in 15 patients for over four weeks it was demonstrated that, depending on the dose of the drug, there was an increase in anticoagulation. The dose of phenprocoumon had to be reduced by 20.6 or 28.7%, respectively, when BM 15.075 was given at a dose of 450 or 600 mg. There was an inhibition of collagen-induced platelet-aggregation. In parallel there was an increase in bleeding time. Fibrinogen concentration was slightly but statistically not significantly decreased. Euglobulin lysis was shortened, especially if previously abnormally long. There was no direct influence on other plasmatic clotting factors.

Aged↗
PubMed1977

Methoxytyrosine formation as an indicator of catechol-O-methyltransferase activity in rat liver in vivo.

The O-methyl derivative methoxytyrosine accumulated rapidly in rat liver after an intraperitoneal injection of L-dopa (50 mg/kg) in combination with 3-hydroxybenzylhydrazine, an inhibitor of the aromatic amino acid decarboxylase. Methoxytyrosine levels reached a plateau 40--60 min after i.p. injection of L-dopa, of which the tissue concentration declined monoexponentially. Injection of various doses of L-dopa revealed that methoxytyrosine formation was saturable and followed enzyme kinetics in rat liver. The catechol-O-methyltransferase inhibitors pyrogallol, tropolone and alpha-propyldopacetamide as well as the inhibitor of the aromatic amino acid decarboxylase benserazide inhibited the formation of methoxytyrosine dose-dependently and concomitantly increased the tissue concentration of dopa. The accumulation of methoxytyrosine from exogeneously applied L-dopa appears to be a reliable indicator of the in vivo activity of catechol-O-methyltransferase.

Amino Acids↗
PubMed1977

[Severe factor XIII-deficiency. Studies on subunits and turnover of the fibrin stabilizing factor (author's transl)].

An infant with congenital homozygous factor XIII deficiency demonstrated a severe retroperitoneal and intracerebral bleeding with development of a posthemorrhagic hydrocephalus in the first months of life. Factor XIII activity was not measurable by means of enzymatic method and the antiserum inhibition test. Quantitative immunoelectrophoresis according to Laurell presented absence of the subunit A, whereas the concentration of subunit S was reduced to 47% the normal value. After replacement therapy factor XIII activity was estimated at 23% and corresponded to the concentration of the subunit A, concentration of subunit S increased by 20%. The turnover rate of fibrin stabilizing factor could be observed over a period of 39 days. The half life was estimated at 4,7 days. The child developed normally after continous substitution with 250 units of factor XIII concentrate every 6 weeks.

Cerebral Hemorrhage↗
PubMed1977

Interaction of haloperidol and gamma-butyrolactone with (+)-amphetamine-induced changes in monoamine synthesis and metabolism in rat brain.

The interaction of (+)-amphetamine with haloperidol and gamma-butyrolactone on synthesis of monoamines in rat brain regions was investigated using an in vivo method, in which the accumulation of dopa and 5-hydroxytryptophan (5-HTP) was measured after inhibition of the aromatic amino acid decarboxylase by means of 3-hydroxybenzylhydrazine. The accumulation of 3-methoxytyramine (3-MT) after inhibition of the monoamine oxidase with pargyline was taken as an indicator of the in vivo release of dopamine (DA) into the extraneuronal space. (+)-Amphetamine at doses of 1--3 mg/kg caused an increase of dopa formation in the DA-rich areas c. striatum and mesolimbic forebrain but had no effect on dopa formation in neocortex and 5-HTP formation in all brain regions investigated. At a dose of 10 mg/kg (+)-amphetamine decreased dopa as well as 5-HTP formation in all brain regions studied. 3-MT accumulation in whole rat brain was stimulated by (+)-amphetamine as well as haloperidol and inhibited by gamma-butyrolactone. Combined treatment with haloperidol and (+)-amphetamine not only potentiated the stimulation of dopa formation but also the increase of 3-MT accumulation. Pretreatment with gamma-butyrolactone antagonized the stimulation of 3-MT formation induced by (+)-amphetamine at a dose of 10 mg/kg. This dose of (+)-amphetamine markedly counteracted the gamma-butyrolactone-induced increase in dopa formation especially in the DA-rich areas. The data support the view that impulse flow in DA neurons facilitates the effect of (+)-amphetamine on DA release and DA synthesis. Inhibition of catecholamine synthesis after high doses of (+)-amphetamine may be due to an increase in cytoplasmatic DA concentration causing end-product inhibition of tyrosine hydroxylase.

4-Butyrolactone↗