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Biomedical subjects

W Schmidt

Publications and source records attributed to W Schmidt.

At least 739 records · Page 41Linked to original sources
PubMed1977

[Psychopharmacological influence on the prey catching behavior of ferrets (Putorius furo L.) (author's transl)].

The prey-catching behavior of ferrets (Putorius furo L.) consists mainly of instinctive behavior patterns, which can be elicited only through their releaser. Then they are performed stereotypically. To get information concerning the central background and the hierarchical structure of this behavior the neuroleptics Haloperidol (0.14 mg/kg), Clozapine (10 mg/kg) and Chlorpromazine (4 mg/kg) were injected i.m. under controlled conditions. In a conditioning experiment the reactivity of the animals was examined. This conditioned reaction was strongly decreased by the drugs. The reaction to the natural stimulus the prey was changed, but not suppressed. The modification of the predatory behavior was manifedsted in an "improvement" of orientation reactions when pursuing the prey and in a better placement of bites. This effect, most evident with Haloperidol, is possibly due to the specific neuroleptic component of the substances. A delay in approaching the prey, or even the total suppression of the prey-catching behavior is suggested to be due to a sedative component which was most obvious in some experiments with Clozapine. On the other hand, there are behavioral elements like the use of paws which are not effected by the neuroleptics. From these and other observations, it is concluded, that the predatory behavior of the ferret has a hierarchically organisated structure. Further it is suggested that some functional connected parts of the behavior have distinct central representation, for they are not influenced in the same way by these drugs.

Animals↗
PubMed1977

Morbidity in alcoholics. Evidence for accelerated development of physical disease in women.

The physical disease profiles of 135 female and 736 male inpatient alcoholics, similar in age, social class, and referral pattern, were compared to further clarify the widespread clinical impression that female alcoholics are more illness-prone. Although the women had been drinking hazardously for fewer years, at admission the prevalence of most diseases was similar in men and women. There was, however, an excess of anemia in women and of fatty liver and chronic obstructive lung disease in men. Furthermore, the average duration of hazardous drinking before the first recorded occurrence of almost all illness events was shorter in women, the sex differences being statistically significant for fatty liver, hypertension, obesity, anemia, malnutrition, gastrointestinal hemorrhage, and an ulcer requiring surgery. These findings suggest that the development of physical morbidity in relation to hazardous drinking may be accelerated in women.

Adult↗
PubMed1977

Specific inhibition of phototropism in corn seedlings.

Geotropism was used as a control for the specificity of potential inhibitors of phototropism by the coleoptiles of corn (Zea mays) seedlings. The compounds tested fall into three categories showing: (a) no inhibition of either phototropism or geotropism (KCl); (b) nonspecific inhibition of both phototropism and geotropism (KCN); and (c) specific inhibition of phototropism (KI, NaN(3), and phenylacetic acid). Simultaneous irradiation of coleoptiles with phototropically inert light in addition to the phototropically active blue light also results in an inhibition of phototropism. Since azide, iodide, and phenylacetic acid are known to interact with flavins while a simultaneous irradiation with a phototropically inert light may depopulate the first triplet state of flavins, these data support the hypothesis that the photoreceptor pigment for phototropism in corn is a flavin.

Journal Article↗
PubMed1977

Stereoselective drug distribution and anticoagulant potency of the enantiomers of phenprocoumon in rats.

The elimination, distribution and anticoagulant activity of S(-)-, R(+)-, and R,S(+/-)- phenoprocoumon were determined in male Wistar-Lewis rats after intravenous injection of a single dose of 0.6 mg kg-1. From the plasma concentrations which elicited the same anticoagulant effect, S(-)-phenprocoumon was 4 to 5 times more potent than R(+)-phenprocouman. The potency of the racemate was between those of the enantiomers. The mean biologic half-life of the S(-)-enantiomer was shorter (12-5 h) than that of R(+)-phenprocoumon (17-8 h). No differences were observed in the apparent volume of distribution. However, the mean liver:plasma concentration ratio was higher for the S(-)-(6-9) than for the R(+)-enantiomer (5-2). At a total concentration of 16-8 microgram ml-1 the percentage of unbound drug in rat serum was significantly higher for the S(-)- (1-13%) than that for the R(+)-enantiomer (0.76%). Values obtained for the racemate were always between those of the enantiomers. It is concluded that stereoselective differences in the distribution between plasma and liver, and consequently in the rate of elimination are most likely due to stereoselective differences in serum protein binding. The greater anticoagulant potency of the S(-)- over the R(+)-enantiomer, cannot be explained primarily by the observed pharmacokinetic differences.

4-Hydroxycoumarins↗
PubMed1977

Tetrahydrofolate-dependent biosynthesis of ribothymidine in transfer ribonucleic acids of Gram-positive bacteria.

Trimethoprim, an inhibitor that prevents tetrahydrofolate-dependent transmethylation reactions inbacteria, was used in a comparative study to discriminate between two possible biosynthetic pathways, either the S-adenosylmethionine or the tetrahydrofolate-dependent formation of ribothymidine (rT) in transfer ribonucleic acids (tRNA's) of several strains of gram-positive and gram-negative microorganisms. rT-deficient tRNA's accumulate in trimethoprim-treated gram-positive Streptococcus faecium, Staphylococcus aureus, Corynebacterium bovis, Arthrobacter albidus, and all examined Bacillaceae, except Bacillus stearothermophilus. The rT-deficient rT-deficient tRNA's accept the methyl moiety from S-adenosylmethionine in vitro, with extracts from Escherichia coli (wild type) as a source of methylating enzymes; 90% of the incorporated methyl groups are present in rT. Trimethoprim does not inhibit the biosynthesis of rT in tRNA of gram-negative Enterobacteriaceae, Rhizobium lupini, and Pseudomonadaceae, suggesting that the rT-specific tRNA methyltransferases of these gram-negative strains use S-adenosylmethionine as coenzyme.

Arthrobacter↗
PubMed1977

Demonstration of granulocytic proteases in plasma of patients with acute leukemia and septicemia with coagulation defects.

To show whether direct proteolysis of coagulation factors may play a role in patients with so-called consumption coagulopathy, granulocytic neutral proteases in the plasma of patients with acute myelocytic leukemia and septicemia were assayed by one- and two-dimensional Laurell electrophoresis. Complexes between serum alpha1-antitrypsin and elastase-like granulocytic protease could be demonstrated in those patients with acute myelocytic leukemia and septicemia who also had moderate or severe coagulation defects. Despite the presence of a high antiprotease potential, addition of the elastase-like enzyme to normal plasma resulted in coagulation defects in vitro comparable to those seen in the patients. These results and the ability of the elastase-like protease to destroy isolated clotting factors suggested that in certain types of coagulation factor deficiencies direct proteolysis rather than consumption of clotting factors due to disseminated intravascular coagulation may be operational.

Blood Coagulation Disorders↗
PubMed1977

[Assesment of RBE of fast neutrons in Ehrlich ascites tumor cells by analysis of mitotic depression (author's transl)].

The depression of mitosis 1 hr following various doses of fast neutrons (6.2 Mev) and gamma rays was studied in an Ehrlich ascites carcinoma of mouse. Doses of 50, 100, 200 and 300 rad of either radiation yielded in the semilogarithmic plot a linear dose dependence of mitosis inhibition. From the regression straight line obtained the Relative Biological Effectiveness was determined, which declined from 2.8 at 50 rad to 1.8 at 300 rad neutron dose. The RBE is given analytically for the dose range investigated in dependence on neutron dose.

Animals↗
PubMed1977

[A method for determining the biological effectiveness of ionizing irradiation by evaluation of mitotic depression of Ehrlich-ascites-tumour cells (author's transl)].

In the present paper there are given the conditions for evaluating the biological effectiveness of Co60-gamma-irradiation by determination of mitotic depression at a defined time after irradiation. Using the model of Ehrlich-ascites-tumour of mice the mitotic index was determined four days after inoculation and one hour after irradiation for doses of 50, 100, 200 and 300 rad. The dose-effect curve- show in the given range of doses an unambiguous dependence of the mitotic depression on the applied dose which can be clearly represented semilogarithmically by regression analysis in an analytical manner. Hence, this dependence may be useful for comparative studies of biological effectiveness of radiation with different LET.

Animals↗
PubMed1977

[Blood transfusions in the course of anaesthesia and professional accuracy (author's transl)].

The usual hazards of blood transfusions will increase in the course of operations, thus in the course of anaesthesia as well. A safe system of checking blood transfusions is required, which corresponds to the justified request of the patient to be protected against damages and is coinciding with the professional accuracy. An approved system of arrangements for clinical practice is described.

Blood Group Incompatibility↗