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Biomedical subjects

P Goetz

Publications and source records attributed to P Goetz.

At least 73 records · Page 4Linked to original sources
PubMed1976

Relationship between experimental results in mammals and man. II. Cytogenetic analysis of bone-marrow cells after treatment of cytembena and cyclophosphamide- cytembena combination.

Cytogenetic analysis and the micronucleus test of bone-marrow cells was used to study the possible extrapolation of results from experimental animals to man. Cytembena was given i.p. in doses of 5, 10, 20, 40 and 80 mg/kg body wt. to Wistar rats and in doses of 20, 40 and 80 mg/kg body wt. to ICR mice and to Chinese hamsters. Five patients with various types of malignancy, so far medically untreated, received 20 mg Cytembena/kg body wt i.v. A combination of Cytembena and cylophosphamide was applied i.p. in single equal doses 1 : 1 of 5,10, 20, and 40 mg/kg body wt to ICR mice, Chinese hamsters and Wistar rats. Patients were given i.v. 20 mg Cytembena and 20 mg cyclophosphamide/kg body wt. Bone-marrow cells were examined 24 h after the administration. The frequency of abnormal metaphases and chromosomal breaks after Cytembena treatment was low; nonetheless, the indicated dose-effect relationship was found in all the rodents used. The frequency of chromosomal breaks was 2--3 times higher in rodents in comparison with man, after treatment with a dose of 20 mg Cytembena/kg body wt. Highest frequencies of induced aberrations were found in mice. The rodents appeared to be 3--4 times more sensitive to the induction of chromosomal breaks and abnormal metaphases than man, after a dose of 20 mg Cytembena and 20 mg cyclophosphamide/kg body wt. The micronucleus test may be regarded as a screening method for assessing mutagenic activity of chemical compounds. Chromosomal analysis and the micronucleus test were about equally convincing in detecting mutagenic effects even with the lowest doses of drugs used. However, the dose-effect relationship was more pronounced in chromosomal aberrations than in the micronucleus test.

Acrylates↗
PubMed1975

Identification of human male meiotic chromosomes.

The study is based on examinations of surgical testicular biopsies performed in eleven men aged from 19-79 years (300 cells at leptotent stage, 19 at zygotene, 300 cells at pachytene, 490 spermatocytes at diakinesis/first metaphase and 23 cells at the second metaphase of meiotic division), as well as post-mortem necropsies taken from six men aged from 19-51 years (6,000 cells at the first meiotic prophage). Identification of chromosomes at leptotene and zygotene stages is limited to the determination of X and Y chromosomes enclosed in the sex vesicle. At the pachytene stage, identification of chromosomes can make use of the differences in their length and number of chromomeres, but is feasible only in figures with good chromosome spreading. Identification of chromosomes at diakinesis/first metaphase in preparations stained by classical methods rests on the size and shape of the bivalents. Application of centromeric heterochromatin staining technique enables us to differentiate among bivalents Nos. 1, 2, and 3, to recognize bivalents belonging to the B group, to identify bivalents Nos. 9, 16, 17-18, and to distinguish between bivalent No. 21 and 22. It further permits the modality of pairing of the X and Y chromosomes to be determined by their short arms. Chromosomes of secondary spermatocytes at metaphase show typical morphological characteristics essential for karyotyping, so that it is possible to arrange them into the haploid karyotype, analogous to the karyotype of somatic cells. Male germinal cells undergo very rapid autolytic changes. No spermatocytes at diakinesis/first metaphase stage could be detected in specimens taken as early as 2 hours after death. The morphology of chromosomes of cells at earlier stages of the first meiotic prophase was markedly altered. Post-mortem testicular material was found unsuitable for an analysis of meiotic chromosomes.

Adult↗