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Biomedical subjects

M Bauchinger

Publications and source records attributed to M Bauchinger.

At least 127 records · Page 7Linked to original sources
PubMed1983

The suitability of the human lymphocyte micronucleus assay system for biological dosimetry.

Human whole blood was irradiated with 220 keV X-rays at doses of 0-4.0 Gy. After incubation periods of 48, 60, 72, 84 and 96 h, lymphocytes were prepared without colcemid pretreatment according to 2 different methods, and micronuclei were scored. The crucial point of lymphocyte preparation was found to be the osmotic pressure of the hypotonic solution. Only a method that preserves the cytoplasm of lymphoblasts is suitable for a correct association of micronuclei with the main nucleus. Similar as for structural chromosome changes, now their intercellular distribution can be analysed. This is necessary for the derivation of appropriate statistical weights which have to be used for more reliable regression analyses. For 48 h, the data can be described by the linear model, for 84 and 96 h, by the linear-quadratic model. For 60 and 72 h no such definite conclusions can be drawn. For calibration purposes a standardized culture time cannot be recommended. Because the background frequency is high, the lymphocyte micronucleus assay system is not sensitive enough to detect a significant increase in the incidence of micronuclei after exposure to low doses (less than 0.3 Gy).

Cell Nucleus↗
PubMed1983

Application of conventional and FPG staining for the analysis of chromosome aberrations induced by low levels of dose in human lymphocytes.

Human peripheral lymphocytes were irradiated with 0.05-0.5 Gy of 220 keV X-rays. After application of either a conventional or the fluorescence plus Giemsa (FPG) staining technique, the dose response for dicentrics and acentrics was studied. The analysis of exclusively first-division cells (M1), carried out by the FPG method, revealed significantly higher aberration yields as compared with the results of the conventional method. The data from M1 cells support the assumption of a linear dose response for both dicentrics and acentrics. The results are discussed with regard to the application of chromosome analyses for a cytogenetic dosimetry after exposure to low levels of ionizing radiation.

Chromosome Aberrations↗
PubMed1983

Cytogenetic effects of an alkyl-lysophospholipid derivative in human peripheral lymphocytes exposed in vitro and in vivo.

Chromosome analyses were carried out in human lymphocytes exposed to an antitumor alkyl-lysophospholipid (ALP) in vitro and in vivo. There was no evidence for a significant clastogenic effect or incidence of an increased sister-chromatid exchange (SCE) after short-term and long-term treatment of unstimulated or stimulated lymphocytes with concentrations of 0.1-50 micrograms ALP per ml. Cell proliferation was delayed after G0 exposure to 50 micrograms/ml. Although no ALP monotherapy was present for 3 cancer patients examined before and during ALP treatment with accumulated doses of 15-516 mg/kg, the cytogenetic data were in accord with the negative experimental results.

Antineoplastic Agents↗
PubMed1983

Dose-effect relationship for 14.5 MeV (d + T) neutron-induced chromosome aberrations in human lymphocytes irradiated in a man phantom.

Human lymphocytes were irradiated with 14.5 MeV (d + T) neutrons at the positions sternal, retrosternal, liver and gonads of a waterfilled Plexiglas man phantom of 37 degrees C. After BUdR treatment of lymphocyte cultures and FPG-staining of metaphases, exclusively first post-irradiation divisions (M1-cells) were analysed. A regression analysis was carried out by means of a weighted least-squares method. Dose-effect relations of dicentrics and acentrics could be fitted by the linear-quadratic model. A comparison of the dose-effect curves established with either conventional or FPG-staining technique revealed statistically significant differences. The M1-evaluation yielded about 46 per cent more dicentrics and about 37 per cent more acentrics. The consequences of these results are discussed in relation to the application of chromosome analysis in 'biological dosimetry'.

Chromosome Aberrations↗
PubMed1982

Chromosome changes in lymphocytes after occupational exposure to toluene.

Cytogenetic analyses were carried out in peripheral lymphocytes from 20 male workers exposed only to toluene in a rotogravure plant for more than 16 years. As compared with a group of 24 unexposed controls, significantly higher yields of chromatid breaks, chromatid exchanges and gaps were observed. The number of SCEs was significantly increased in smoking and non-smoking toluene-exposed workers compared with the corresponding control groups.

Chemical Industry↗
PubMed1981

Chromosome changes in human lymphocytes after separate and combined treatment with divalent salts of lead, cadmium, and zinc.

Unstimulated human lymphocytes in whole blood were treated for three hours with lead, cadmium, and zinc acetate separately and in combinations of two or three metal salts with different concentrations of between 10(-3) and 10(-5) moles, respectively. Untreated cultures and sodium acetate-treated samples served as controls. Chromosome analysis from 48 cultures revealed higher incidences of chromatid-type aberrations and gaps only for cultures exclusively treated with cadmium. The results are discussed under the respect of heavy metal metabolism in human lymphocytes.

Cadmium↗
PubMed1981

Analysis of structural chromosome changes and SCE after occupational long-term exposure to electric and magnetic fields from 380 kV-systems.

Chromosome analyses were carried out in lymphocytes of 32 workers occupationally exposed for more than 20 years to 50 Hz alternating electric magnetic fields in 380 kV switchyards. As compared with a control group of 22 workers of similar age and occupation but without field exposure neither the yields of structural chromosome changes nor the SCE-frequencies were increased. The difference of cytogenetic data after occupational exposure to ionizing radiation is discussed.

Adult↗
PubMed1981

Azathioprine, a clastogen in human somatic cells? Analysis of chromosome damage and SCE in lymphocytes after exposure in vivo and in vitro.

Chromosomal analyses in lymphocytes of 28 patients with multiple sclerosis were carried out before, during and after Azathioprine (Aza) therapy. Only a higher incidence of gaps was found in treated patients than in a group of healthy persons but not in comparison with untreated patients. Similarly, no significant clastogenic effect was observed in vitro after short-term and long-term treatment of unstimulated and stimulated lymphocytes with concentrations of 1--100 microgram Aza per ml. Treatment of cultures with 0.0001--4.0 microgram/ml did not yield increased SCE frequencies. The absence of any significant clastogenic effect of therapeutic doses of Aza on human somatic cells is deduced from an evaluation of previously published data and from the present results.

Adult↗
PubMed1980

Analysis of primary processes in the foramtion of acentric fragments.

An analysis of primary processes in the formation of excess acentric fragments in human lymphocytes was carried out in experiments with 220 kV X-rays after acute exposure (D = 50 R/min, 25--400 R) and fractionated exposure (340 R split into two equal fractions, separated by intervals between 50--360 min). Chromosome analyses occurred after conventional staining. Applying G-banding data from an acute X-irradiation experiment representative dose-effect curves for acentrics could be established which take into account one-break and two-break events in the formation of this aberration type. For the time dependent primary breaks necessary for the formation of two-break two-track acentrics a mean interaction time t approximately = 102 min could be calculated. This is well in line with the corresponding time t approximately = 110 min for dicentrics. The distribution of acentrics among cells shows the phenomenon of overdispersion.

Chromosome Aberrations↗
PubMed1979

Distribution of radiation induced lesions in human chromosomes and dose-effect relation analysed with G-banding.

Human female lymphocytes were exposed to X-rays in vitro at 7 different doses between 40-280 R. In 830 metaphases chromosome analyses were carried out with either conventional staining or G-banding, respectively. 486 breakpoints are non-randomly distributed between chromosomes and chromosome arms. An excess of lesions was present in chromosomes 1 and 5 or in 1p. 85% of the lesions were located in G-negative bands (pale G-bands). 29% of all lesions appeared in either the last terminal pale band (21%) or in the centromere region (8%). With regard to an application of G-banding for a biological dose-estimation, the dose-response relations of dic and ace were analysed. Although G-banding enables detailed analysis of the whole karyotype it cannot be recommended for cytogenetic routine analyses in medical radioprotection monitoring, without suitable automated scoring techniques. Dose estimations based on the frequency of dic and carried out with conventional staining cannot be essentially improved at present with banding. Nevertheless, by banding criteria for a correct evaluation of other aberration types, e.g. ace, can be provided. This is a prerequisite for the calculation of representative dose-effect curves.

Chromosome Aberrations↗
PubMed1979

Calculation of the dose-rate dependence of the decentric yield after Co gamma-irradiation of human lymphocytes.

The dose relation for dicentrics after in vitro Co gamma-irradiation of human lymphocytes with dose rates of 50 and 1.7 rad/min fit the linear-quadratic function y=alpha D + beta D2. Compared with 50 rad/min, after 1.7 rad/min alpha D was unchanged, whereas beta D2 was decreased by 36 percent. By applying the mean interaction time t approximate to 110 min for primary breaks, determined in an earlier experiment, and Lea's G-function, a theoretical dose relation for 1.7 rad/min can be calculated from the corresponding experimental curve. Thus, from calibration curves with conventional dose rates dose-effect curves for low dose rates can be derived without the need for time-consuming chromosome analyses.

Cells, Cultured↗
PubMed1978

Chromosome analyses in man in the course of chemoprophylaxis against tuberculosis and of antituberculosis chemotherapy with isoniazid.

Cytogenetic analyses were carried out in lymphocytes of 37 persons before and during a primary chemoprophylaxis or a preventive chemotherapy with isoniazid as well as of 30 patients suffering from active pulmonary tuberculosis before and during a chemotherapy with isoniazid in combination with two other antimycobacterial drugs. The results of the four participating research groups consistently reveal no indication for a chromosome damaging activity of isoniazid, of its metabolites in the human organism and of the administered drug regimens.

Adolescent↗
PubMed1978

The cytogenetic effect of bleomycin on human peripheral lymphocytes in vitro and in vivo.

The cytogenetic effect of bleomycin (BLM) in human lymphocytes was studied after exposure to different doses during the G0 and G2 phases. BLM produced a marked specific effect on the cell cycle. The main aberration types after exposure in tg0 were dicentrics and deletions; and after exposure in G2, open chromatid breaks. A linear dose--response was calculated for all these aberration types as well as for the number of aberrant cells. In the G2 experiments, partially and totally pulverized cells also increased linearly with dose. The intercellular distributions of the most frequent aberration types after exposure in G0 and G2--the dicentrics and chromatid breaks, respectively--showed over-dispersion. These results show that the cytogenetic effect of BLM may be compared with that of densely ionizing irradiation. Preliminary results of chromosome analysis of three cancer patients in the course of BLM therapy showed effects similar to those in the G0 experiments.

Bleomycin↗