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Biomedical subjects

W Schmidt

Publications and source records attributed to W Schmidt.

At least 685 records · Page 38Linked to original sources
PubMed1980

Effect of induction and inhibition of drug metabolism on pharmacokinetics and anticoagulant activity of the enantiomers of phenprocoumon in rats.

The elimination, distribution and anticoagulant activities of the enantiomers of phenprocoumon were studied in rats following enzyme induction by phenobarbital (pretreatment with 75 mg . kg-1 for 4 days) and enzyme inhibition by chloramphenicol (100 mg . kg-1 h prior to the injection of phenprocoumon and then 50 mg . kg-1 every 12 h). Pretreatment with phenobarbital increased the rate of elimination and decreased the total anticoagulant effect per dose of both enantiomers. It also caused a slight reduction of the liver/plasma concentration ratio of the enantiomers due to the increase of the liver weight and a significant enhancement of the synthesis rate of prothrombin complex activity in non-anticoagulated rats. Chloramphenicol decreased the rate of elimination and enhanced the total anticoagulant effect per dose of both enantiomers. The distribution between plasma and liver remained unaffected. Thus, in rats neither the induction of the phenprocoumon metabolism by phenobarbital nor its inhibition by chloramphenicol appears to be stereoselective.

4-Hydroxycoumarins↗
PubMed1980

[Foetomaternal transfusions after amniocentesis in early pregnancy - evaluation of 1,000 cases (author's transl)].

The foetal haemoglobin (HbF) content was determined before and 2 hours after amniocentesis in 1,000 cases of amniocentesis conditioned by genetic indication (between the 15th and 20th pregnancy week). HbF-identification was effected according to the method of Kleinhauer and Betke. In primarily (before amniocentesis) negative HbF findings, HbF positive findings after amniocentesis were obtained in 7.2% of the patients. However, if the HbF-determinations were positive already before amniocentesis, a quantitative increase of HbF-cells in the maternal blood smear after amniocentesis was observed in 15.9% of the patients. Patients with punctures in the case of placenta of the anterior wall showed and increase in HbF values after amniocentesis in 12.2% of the cases, compared against 8.9% only in patients with posterior wall placenta, but these differences were statistically not significant. Amniocentesis under ultrasonic visual control caused a drop in the number of repeated amniocentesis trials to 20/500, aspiration of bloodstained amniotic fluid to 3.6% and HbF-cell positive blood smears after amniocentesis to 7%. (Free-hand-needle-technique: amniocentesis failures 42/500, amniotic fluid samples contaminated with blood in 9.6% of the cases and increases in HbF-values after amniocentesis in 12.6% of the cases). A total of 82 Rh-negative patients were given conventional anti-D-prophylaxis independent of the localisation of placenta. No sensitization was observed in any of the cases. No boosting was caused by early amniocentesis in cases where a positive anti-body finding had been established (3 cases to date).

Amniocentesis↗
PubMed1980

[Aminoacetonitrile and fetogenesis of the rat. II. Malformations of organ systems (author's transl)].

We investigated the action of the lathyrogenic compound aminoacetonitrile (300 mg/kg body weight) on fetogenesis of the Wistar rat. In a 1st section we dealt with influence on the outer body shape and common reproductive parameters (WENDLER and coworkers 1980). This 2nd section describes toxic effects on internal organs and malformations on organ systems detected by free-hand razor blade technique. Especially, we observed cardial ectopia, rupture of the ascendant aorta, situs inversus, hydrocephalia, hydronephroses, and dystopic kidneys. Enlargement of heart atria, and main thoracic veins, dilatations of salivary gland ducts and bronchial tree are considered to be nonspecific toxic effects of aminoacetonitrile.

Abnormalities, Multiple↗
PubMed1980

[Application of the serological clostridium assay in tumour diagnostics (author's transl)].

The suitability for serologic tumour diagnostics of the non-oncolysing strain Clostridium butyricum CNRZ 528 has been investigated. By introducing the transplantable Brown Pearce tumour of the rabbit and spontaneous tumours of the dog as test models the antibody production against clostridial rods--indicating malignant growth as had been proved with the Möse strain Cl. oncolyticum M55--has been evaluated. It could be established--utilizing the complement fixation test--that one serological method alone is not sufficient for obtaining clear-cut test results in anyone case. It is to be recommended that the indirect hemagglutination and the complement fixation tests ought to be combined. Our studies on specific clostridial antigens and on optimization of techniques will be continued.

Animals↗
PubMed1980

[Aminoacetonitrile and fetogenesis of the rat. III. Malformations of the osseous skeleton (author's transl)].

The paper describes disturbances of ossification and malformations of the osseous skeleton of rat fetuses after application of 300 mg aminoacetonitrile/kg body weight during fetogenesis (days 15--19). Malformations are inducible at all days proved: Single doses of the lathyrogenic agent (intraperitoneally applicated) produce severe scoliosis, bending of extremities, wristdrop of the fore paws, shortening of the lower jaw, cleft palate and distorsion of the ribs. This paper is a continuation of 2 preceding parts dealing with general parameters of reproduction and gross anomalies after application of aminoacetonitrile, and disturbances of internal organ systems.

Acetonitriles↗
PubMed1980

[Formation of amnion cord in a young defective human embryo (author's transl)].

A report about a human embryo of about 4 weeks of age afflicted with the formation of amnion cord with a slinglike formation. The corion sac had on its surface only a sparse cover with chorion vili. The intraembryonical vascular system was not shown except of small partial spaces in the front sector. The cause for the formation of an amnion cord is seen primarily in a faulty supply of the amniotic sac with its content. The formation of an amnion cord has been interpreted for this early phase of the embryogenesis as follows: In sufficiency of nourishment led to a dehiscence of the amnion. Mesenchym entered from the extraembryonal celom and combined itself with the lateral wall of embryo which showed because of insufficient nourishment in one area of defective epithelium. The mesenchym, which surrounded the frontal trunk part did not connect with the embryo and grew because of growth pressure into a loop with collagenous fibers. Amnionepithelecells spread only secondarily over the mesenchymloop and epithelialized it.

Abortion, Spontaneous↗
PubMed1980

[Criteria for the use of the linear allothermal short-time test in predicting stability (author's transl)].

Three selected model substances of varying activation energy (naphazoline, 109 kJ/mole; acetylsalicylic acid, 72 kJ/mole; and phenobarbital, 60 kJ/mole) were studied to determine the conditions under which the allothermal short-time test according to Zoglio (linear increase in temperature) will yield stability predictions which are consistent with those provided by the isothermal short- or long-time test. The error of the determination method should be less than or equal to 1%. It is advantageous to use for the calculation as many data as the analytical facilities will permit to obtain. The actual value for the respective temperature should differ from the desired value by < +/- 0.2%. The increase in temperature should be very slow 1-2 degrees C/h at best). This is particularly true for substances of low activation energy, because more the energy values calculated on the basis of the allothermal test differ from the isothermally determined values, the flatter is the curve provided by the arrhenius equation. The temperature range should be chosen as large as possible, from 30-90 degress C, and the experiment should be continued until at least a 10% decomposition is achieved. On calculating the collision factor A and the reaction-rate constant for any temperature, it has proved useful to continue the experiment isothermally at the final point of the allothermal test.

Aspirin↗
PubMed1980

[Aminoacetonitrile and fetogenesis of the rat. I. Fetal toxicity and gross malformations (author's transl)].

We investigated the influence of the lathyrogenic compound aminoacetonitrile (AAN) on fetogenesis of the rat. In late pregnancy AAN induces nonspecific toxic effects resulting in hemorrhages, edema, disturbance of weight development, and severe interaction with viability. In fetogenesis AAN induces malformation rates of 100% by contrast with the developmental stages of blastogenesis and embryogenesis. Furthermore, the present paper deals with gross anomalies after application of AAN in fetogenesis. We observed: disturbances of outer body shape, micrognathia, wrist-drop, malrotation of hind extremities, kinked tails, humpback, cardial ectopia. The paper will consist of 4 parts dealng with anomalies of organ systems, skeletal abnormalities, the mechanisms of action of lathyrogenic compounds.

Abnormalities, Drug-Induced↗