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H G Miltenburger

Publications and source records attributed to H G Miltenburger.

At least 37 records · Page 2Linked to original sources
PubMed1983

Criteria for the standardization of Salmonella mutagenicity tests: results of a collaborative study. II. Studies to investigate the effect of bacterial liquid culture preparation conditions on Salmonella mutagenicity test results.

The influence of various parameters and growth conditions in the "overnight culture" of Salmonella typhimurium strains on mutagenicity test results was investigated. A number of factors were first suspected to be of some importance for the quantitative outcome of the mutagenicity test. None of them, however, was found to influence the results to such a marked extent as to be a major source of variability. Only the brand of nutrient broth used for the propagation of the bacteria proved finally to have a certain effect on the number of (spontaneous and induced) revertant colonies, although no precise and quantitative statements can be made with regard to a possible standardization of this experimental segment in the Salmonella mutagenicity test. The occurrence of such unpredictable but noticeable influences is, however, evidence for the importance of an intralaboratory optimization and standardization of all parts of the test procedure.

Animals↗
PubMed1983

Morphogenesis of nuclear polyhedrosis virus from Autographa californica in a cell line from Mamestra brassicae (cabbage moth). Further aspects on baculovirus assembly.

Cultures of cell line IZD-MB 0503 from Mamestra brassicae were inoculated with nonoccluded nuclear polyhedrosis virus of Autographa californica (AcNOV). At 1 h postinoculation (p.i.) nucleocapsids were found in the cytoplasm near nuclear pores and within the nucleoplasm. Formation of virogenic stroma was observed at 7 h p.i. The first short empty capsids were seen at 10 h postinoculation (p.i.), followed by partially and completely filled nucleocapsids (11-12 h p.i.) with most capsids filled at 12 h and later. This suggests that nucleocapsid components, such as capsid and DNA-core, assemble in successive stages rather than simultaneously. Viral progeny, being released from the cells by budding, were observed at 13 h p.i.

Animals↗
PubMed1980

The effect of cyclophosphamide and isoniazid (INH) alone and in combination on the centromere separation sequence in Chinese hamster bone marrow cells.

X-irradiation of Chinese hamsters with 50 and 200 rad delayed the centromere separation of bone marrow chromosomes. Combination of a treatment with 13.3 mg cyclophosphosphamide/kg body wt. and 50 rad did not result in an enhanced effect compared with the single treatments. Again, the separation sequence was not influenced. No delay was induced by a treatment with 125 mg isoniazid/kg, but a slightly and significantly earlier separation of the chromatids in both groups of metacentric and acrocentric chromosomes occurred. The separation delay seen after irradiation with 50 rad disappeared when the animals were pretreated with isoniazid. Independently of these results the asynchronous separation sequence was not altered in any of the experiments.

Animals↗
PubMed1980

Busulphan-induced chromosomal aberrations in intestinal cells of Chinese hamster.

Chinese hamsters were given Busulphan, 25 and 50 mg/kg bw. After 18 h, chromosomes of the lining cells of the upper intestinal tract were prepared according to a newly developed method. The aberration rate was enhanced by a factor of about 25 after 25 mg/kg, but 50 mg/kg bw did not induce higher aberration rates. In the same animals the dose-dependent aberration rates were also determined in bone-marrow cells. Furthermore, the formation of SCEs in intestinal cells was observed. In a preliminary experiment, metaphase plates from intestinal cells of mice were prepared, too.

Animals↗
PubMed1980

Mass production of insect cells in suspension.

The production of insect pathogenic viruses for the use in integrated pest control is presently done in vivo in populations of their natural hosts. However, efforts are made in several laboratories to produce some of these baculoviruses in insect cell cultures. The mass production of the viruses in vitro depends on a technology for the mass production of cells. Data are presented for the production of up to 10(10) insect cells per logarithmic growth phase in a continuously running fermenter culture at volumes of 9-10 litres.

Animals↗
PubMed1980

Viral pesticides : biohazard evaluation on the cytogenetic level.

Promising agents for integrated pest control are naturally occuring insect pathogenic viruses that belong to the group of baculoviruses. We have performed experiments using mammalian cells from different species in vivo and in vitro to test a possible effect of baculoviruses on chromosome aberration rates and sister chromatid exchanges. No cytogenetic effects were found.

Animals↗
PubMed1980

Testing propafenone hydrochloride in the Ames Salmonella microsome system and in mammalian cytogenetic systems (bone marrow, spermatogonia).

2'-(2-Hydroxy-3-propylaminopropoxy)-3-phenyl-propiophenone-hydrochloride (propafenone-HCl, Rytmonorm) was tested for mutagenic activity in the Salmonella microsome system (Ames test) and in mammalian cell systems. Neither in the Ames test (62.5-1000 microgram/plate) nor in the bone marrow cells and spermatogonia of Chinese hamster (injected doses: 1.57, 3.13, 6.27 mg/kg) there is any evidence for an enhancement of mutation frequencies or chromosome aberration rates. Also, the micronucleus rates were in the control range. Under the experimental conditions of this investigations propafenone-HCl was not mutagenic.

Animals↗
PubMed1978

The effect of isoniazid (INH) on Chinese hamster and mouse spermatogonia.

Acute and chronic treatment of Chinese hamsters and mice with 5, 25 and 125 mg/kg isoniazid (INH) given by oral intubation did not enhance the chromosomal aberration frequencies in spermatogonia. The structural and numerical aberration rates remained in the range of spontaneous events even after the chronic treatment over 12 weeks with 3 x 125 mg/kg INH per week. This dose is much higher than normally used for prevention and therapy in man (3--16 mg/kg).

Animals↗
PubMed1977

The effect of cyclophosphamide on the centromere separation sequence in Chinese hamster spermatogonia.

The sequence of centromere separation in spermatogonial chromosomes of untreated and cyclophosphamide-treated Chinese hamsters is described. Centromeres of chromosome 1 and 2 separated much earlier than all other chromosomes, especially 6-8. Cyclophosphamide significantly inhibits the centromere separation in all chromosome groups but does not alter the sequence of separation.

Animals↗
PubMed1976

Sequence of centromere separation of mitotic chromosomes in Chinese hamster.

Chromosome preparation in late metaphase cells from bone marrow of colcemid treated male Chinese hamsters were used to analyse the sequence of separation of sister centromeres. Chromatids of chromosomes 2 and 1 are the first ones to separate at centromeres, followed by members of group B, D and C. Some acrocentric chromosome is always the last one to separate at the centromere. The data point to a possible correlation between the position of a centromere in the separation sequence in the genome and the amount of centromeric heterochromatin as well as relation to the phenomenon of non-disjunction.

Animals↗
PubMed1976

The effect of insecticides on Chinese hamster cell cultures.

The effect of p,p'-isomers of DDT and its derivatives DDD, DDE and DDA on Chinese hamster cells in culture was studied. At different concentrations and various times of treatment the proliferation rate was inhibited most strongly by DDD and DDT, whereas DDE exhibited a markedly weaker influence. DDA was the least toxic compound of the four. The cytogenetic effects were also different. Again, DDA induced the least damage. Only enhanced gap rates but no chromosome breaks were observed. DDE was more active, and higher break rates occurred. DDD and DDT were by far the most damaging compounds, and they raised the gap and break rates markedly. However, no induction of configuration anomalies was found in any experiment. Chronic treatment of the cells for 3 months with DDT at 8 ppm did not alter the proliferation rate, the sensitivity to acute treatment with higher DDT concentrations or the chromosomal aberration rates. The results are discussed in relation to the relevance of differential pesticide effectivity in organs of higher animals and man.

Cell Line↗
PubMed1976

[On the simultaneous effects of ionising radiation and chemical agents on animal cells. 1st communication. Cytogenetic studies on X-rays and isonicotinic acid hydrazide in the Chinese hamster, Cricetulus griseus (author's transl)].

In bone marrow cells of Chinese hamsters enhanced chromosome damage is observed after 48 h treatment of the animals with isoniazid (INH) combined with X-rays only at much higher doses than normally applied in human therapy. Compared to X-ray-induced aberration levels, 125 mg/kg INH and 50 R given simultaneously increase the number of gaps and breaks, the latter being increased over-additively. This points to an interaction between both agents. The combined treatment changes the mitotic rate of the bone marrow as well.

Animals↗