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M Bauchinger

Publications and source records attributed to M Bauchinger.

At least 19 recordsLinked to original sources
PubMed1997

Cytogenetic and molecular genetic characterization of a chromosome 2 rearrangement in a case of human papillary thyroid carcinoma with radiation history.

Karyotype analysis of a primary culture from a case of papillary thyroid cancer (PTC) showed an abnormal short arm of one homologue of chromosome 2 as sole abnormality in 4 of 16 metaphases. Based on G-banding analysis, two different aberration types on chromosome 2 could be assumed representing either a del(2)(p22-23) or a pericentric inversion. Further comparative genomic hybridization (CGH) analysis as well as fluorescence in situ hybridization (FISH) analysis were performed to confirm the assumed alterations. While CGH analysis showed no loss of chromosome 2 material, FISH with yeast artificial chromosome (YAC) probes homologous to the region 2p22-23 demonstrated two pericentric inversions of chromosome 2 involving different breakpoints on 2p in 6.8% and 4.2% of the metaphases, respectively. Polymerase chain reaction (PCR) analysis with degenerated oligonucleotide primers that bind within the conserved catalytic domain of tyrosine kinase (tk) genes resulted in amplification products with DNA of YAC 851D11 suggesting the presence of such genes at or near the translocation breakpoint.

Adult↗
PubMed1997

Retrospective biodosimetry of Chernobyl clean-up workers using chromosome painting and conventional chromosome analysis.

Blood samples of 52 Chernobyl clean-up workers were analysed by fluorescence in situ hybridization (FISH) using whole-chromosome painting probes for chromosomes 1, 4 and 12, simultaneously with a pancentromeric probe and by conventional chromosome analysis, for radiation-induced symmetrical translocations and dicentrics in T-lymphocytes. Based on FISH measurements of translocations, individual biodosimetry estimates between 0.32 and 1.0 Gy were obtained from 18 cases. Pooled data for the total group of 52 workers provided a collective biodosimetry estimate of 0.23 Gy. For a group of 34 workers with documented doses, the mean dose estimate of 0.25 Gy compared well with the mean documented dose of 0.26 Gy. However, no correlation between individual translocation frequencies (FG) and documented doses could be found. A statistical analysis of the expected dose-response suggests exposures to higher doses than documented for a substantial fraction of workers with ascribed doses < 0.2 Sv. For subjects working repeatedly at the reactor site between 1986 and 1995 the mean translocation frequency was significantly higher than for those working only in 1986. A comparison of dicentric frequencies obtained by conventional scoring and by FISH measurements showed no significant difference, although only two of 52 cases revealed significantly higher yields than the mean control level. Based on conventionally scored dicentric frequencies, a collective biodosimetry estimate of 0.23 Gy could be derived only of the group of persons working at Chernobyl exclusively in 1986 for which a documented average dose of 0.19 Gy was reported.

Adult↗
PubMed1997

Is there reliable experimental evidence for a chromosomal "fingerprint" of exposure to densely ionizing radiation?

A selection of published data on the ratio, F, of interchromosomal to intrachromosomal stable (reciprocal translocations and pericentric inversions) and unstable (dicentric chromosomes and centric rings) exchange aberrations in human lymphocytes has recently been presented as evidence for F values of about 15 for X and gamma rays and about 6 for neutrons and alpha particles (D. J. Brenner and R. K. Sachs, Radiat. Res. 140, 134-142, 1994). On this basis it was proposed that low F values could serve as a chromosomal "fingerprint" of densely ionizing radiation. In the present commentary it is shown that some of the quoted data sets provide little support for this concept. It is further demonstrated that our own data, including a "head-to-head" experiment with gamma rays and alpha particles, reveal no LET dependence, even in the comparison of F values from low-LET radiation with those from low doses of high-LET radiation. In this context it is pointed out that a change in F values cannot be expected at doses of high-LET radiation where the linear component of the dose-effect relationship for exchange aberrations prevails. Additional data for the effects of high- and low-LET radiation which have not been considered in the discussion so far confirm that support of the concept of F-ratio "fingerprinting" by experimental data is insufficient.

Alpha Particles↗
PubMed1997

Health impacts of large releases of radionuclides. Cytogenetic effects as quantitative indicators of radiation exposure.

Scoring of dicentrics in metaphase preparations of human T lymphocytes is the method of choice for estimating individual whole-body doses of radiation exposure. A quantification of partial-body exposures or non-uniform distribution of the dose is more complicated but it can be achieved by using specific mathematical approaches. For retrospective biodosimetry, conventional scoring of dicentrics is less precise because these unstable aberrations are eliminated with time post-exposure. Symmetrical translocations are not selected against during mitotic division in the haematopoietic cell reproductive centres, so the frequencies of these stable aberrations are generally assumed to remain constant even for decades. They can now be analysed precisely by fluorescence in situ hybridization using whole chromosome-specific DNA probes (chromosome painting) with an alpha-satellite DNA probe for centromere detection. Based on in vitro calibration curves established with single or multicolour paints covering 4-22% of the total human genomic DNA content, scoring of translocations has been applied for dose reconstruction in smaller groups of atomic bomb survivors and victims of the Chernobyl and Goiania radiation accidents. However, prior to routine use, the method requires further validation. Such work includes the precise evaluation of the unexpectedly high frequency of complex exchanges (> or = 3 breaks in > or = 2 chromosomes) found both at > 2 Gy doses of low linear energy transfer (LET) radiation and generally for high LET alpha-particles. Data on the long-term stability of translocations and the appearance of clonal abberrations, as well as improved measurements of the linear coefficient of standard calibration curves, are also required.

Centromere↗
PubMed1996

Detection of centromeres in vinblastine- and radiation-induced micronuclei of human lymphocytes using FISH with an alpha satellite pancentromeric DNA probe.

Fluorescence in situ hybridisation (FISH) with a human alphoid satellite pancentromeric DNA probe was used to detect centromeres in micronuclei of human lymphocytes induced by gamma irradiation and by Vinblastine sulfate. In a cytokinesis-block micro-nucleus assay a dose-dependent increase of micronuclei was detected for both agents. 72-89% of vinblastine-induced micronuclei, but only 7-48% of radiation-induced micronuclei showed centromere-positive fluorescence signals. Vinblastine treatment frequencies of centromere-negative micronuclei did not increase compared to control values, nor did frequencies of centromere-positive micronuclei in irradiated lymphocytes. Since FISH with an alpha satellite DNA probe allows the direct detection of centromeric DNA sequences the spindle damaging or clastogenic effectiveness of a compound can be easily and reliably examined in a cytokinesis-block micronucleus assay in human lymphocytes.

Adult↗
PubMed1996

Combined immunophenotyping and FISH with sex chromosome-specific DNA probes for the detection of chimerism in epidermal Langerhans cells after sex-mismatched bone marrow transplantation.

Langerhans cells (LC) of the skin represent bone marrow-derived dendritic antigen-presenting cells and are therefore important in pathophysiological processes such as rejection, graft-versus-host disease, and graft-versus-leukemia-reaction after bone marrow transplantation (BMT). For understanding of these diseases, the evaluation of the chimeric status of LC following BMT is of great interest. To analyze the sex chromosome constitution of LC in the skin, we established a modified and refined technique of combined immunophenotyping and fluorescence in situ hybridization (FISH) and investigated frozen sections of skin biopsies from nine patients after allogeneic sex-mismatched BMT and of two healthy donors for control. LC were specifically labeled using a fluorescent CD1 a antibody and hybridized simultaneously with X and Y chromosome-specific DNA probes. The results of this practical application on nine leukemia patients show the appearance of donor-type LC and the persistence of host-type LC at various times (36 up to 1395 days) after sex-mismatched BMT. Complete chimerism of LC could not be detected in any case. The frequency of recipient-specific LC ranged from 7% to 92% and showed no correlation with time postgrafting. We conclude from our results of 1461 analyzed LC that combined immunophenotyping and interphase cytogenetic analysis by FISH is the method of choice for the assessment of chimerism in a particular cell type after sex-mismatched BMT. Its practical application on other tissues affected by BMT-related pathophysiological processes reveals further knowledge of the time-dependent course of chimeric patterns after BMT.

Acute Disease↗
PubMed1996

Combined cytogenetic and molecular genetic analyses of fifty-nine untreated human prostate carcinomas.

G-banding analyses and molecular genetic investigations (fluorescence in situ hybridization (FISH) and loss of heterozygosity (LOH) studies) were performed in 59 tumor and nontumorous samples of human prostate carcinoma. Clonal chromosome aberrations were detected in 16 tumors of which nine were poorly differentiated (G3) and 11 in an advanced stage (pT3). Six cases showed numerical chromosome aberrations. The most common numerical aberrations were trisomy 7 and loss of the Y chromosome each present in three tumors. Clonal structural aberrations were detected in 12 tumors. Deletions could be observed in two cases affecting chromosome 6q23 and in two cases affecting chromosomal region 16q. A structural variant of the pericentromeric heterochromatin of chromosome 9 became apparent in six cases. The Y chromosome was involved in clonal translocations in two cases, additionally an inversion occurred on chromosome 19 in one case. All clonal chromosomal changes were found exclusively in the tumor sample. For an analysis of the pericentromeric heterochromatin of chromosome 9, FISH using a chromosome 9-specific sat III DNA probe was carried out on metaphase preparations of tumor and nontumorous tissues of two cases showing var(9)(qh). The FISH data suggest a deletion in the pericentromeric heterochromatin. Loss of heterozygosity studies on chromosomal regions 10q and 16q were carried out because both chromosomes were frequently affected by nonclonal structural aberrations. Loss of heterozygosity could be verified in 11 cases.

Aged↗
PubMed1996

Genotoxicity of 4-chloro-o-toluidine in Salmonella typhimurium, human lymphocytes and V79 cells.

In the absence of a metabolizing system (S9 mix) 4-chloro-o-toluidine (4-COT) was found to be ineffective in a combination of assays for gene mutations in Salmonella typhimurium, for chromosome aberrations and sister chromatide exchanges in human lymphocytes, and for the induction of spindle disturbances in V79 Chinese hamster cells. In the presence of S9, 4-COT was also ineffective in producing structural or numerical changes in mammalian cells, but the yields of 4-COT induced revertants in S. typhimurium strains TA 100 and TA 98 were about 2-fold higher than those in controls.

Animals↗
PubMed1996

Quantification of FISH-painted chromosome aberrations after domestic radon exposure.

Chromosome painting (target chromosomes 1, 4, 12) was performed in peripheral lymphocytes from 25 occupants of nine houses with indoor radon concentrations of 210-3000 Bqm-3. Compared to a control group, the mean frequency of symmetrical translocations of the radon group was slightly but not significantly (p < 0.10) increased. A similar tendency became apparent for a comparison of two groups of subjects with cumulative radon exposures above and below 2800 Bqm-3 y. It is concluded that FISH-based measurements of stable symmetrical translocations should reflect the cumulative radon exposure to haematopoietic compartments such as the red bone marrow rather than to mature blood lymphocytes. Since, however, radon-derived bone marrow doses are low and control frequencies of translocations are very high (about 10-fold higher than the value for conventionally scored dicentrics), the observed relative increase (1.5-fold) of the translocation frequency in blood lymphocytes is too small to discriminate chronic radon exposure from background.

Adolescent↗
PubMed1996

Chromosome translocations in thyroid tissues from Belarussian children exposed to radioiodine from the Chernobyl accident, measured by FISH-painting.

Chromosome painting of chromosomes 1, 4 and 12 was performed on metaphase preparations of cultured thyroid cells to analyse the frequency of radiation-induced stable chromosome translocations in papillary thyroid carcinomas from 40 Belarussian children exposed to radioiodine from the Chernobyl accident, and from 31 reference case. As expected, we found the highest translocation frequencies in secondary thyroid tumours after radiotherapy, but there were also high frequencies in tumour tissues as well as in non-tumourous tissues from childhood papillary carcinoma samples from Belarus. Among the Belarussian tumours the cases from the Gomel region exhibited the highest frequency of translocations and five cases lie within the range of frequencies observed in secondary thyroid tumours after radiotherapy. The findings support the assumption that radiation was the principal cause of the tumours in Belarus, but they indicate also that only a minority of the Belarus cases, which have developed papillary carcinomas, were exposed to very high doses of radioiodine.

Adolescent↗
PubMed1996

Chromosome analysis by fluorescence in situ hybridization: further indications for a non-DNA-proportional involvement of single chromosomes in radiation-induced structural aberrations.

The frequencies of symmetrical complete and incomplete translocations and dicentrics induced in human lymphocytes after in vitro irradiation with 3Gy X-rays were analysed by the use of fluorescence in situ hybridization (FISH). Single whole chromosome painting (WCP) probes, specific for chromosomes 1-4, 6-10, 12, 14 and X were hybridized separately. A human pancentromeric DNA-probe was used simultaneously for unequivocal centromere detection. For both aberration types, symmetrical translocations and dicentrics, a significant deviation from a DNA-proportional distribution was found. In general, chromosomes with a higher DNA content (chromosomes 1-3, 6 and 7) were less frequently involved in the formation of symmetrical translocations and dicentrics than expected according to their DNA-content, whereas smaller chromosomes were more frequently involved. The only exception was chromosome 4, exhibiting the highest translocation frequency of all chromosomes analysed. Ratios of the yields of symmetrical translocations to the yields of dicentrics varied between 0.9 and 1.8 for the single chromosomes. The present results substantiate our previous data obtained with identical chromosomes but examined in four different triple combinations.

Chromosome Aberrations↗
PubMed1995

Quantification of low-level radiation exposure by conventional chromosome aberration analysis.

Chromosome dosimetry, in its conventional form largely based on scoring of dicentrics and ring chromosomes in human blood lymphocytes, is the most widely distributed and reliable biological technique in radiological protection to estimate individual whole-body doses of about 100 mGy of low-LET radiation. Attempts to detect and quantify effects even of lower acute doses or protracted and chronic exposures have been repeatedly performed and the results revealed inherent limitations of this approach. Most relevant items, such as extrapolating from high-dose to low-dose effects, the influence of background frequency of dicentrics on the dose estimates, dose accumulation and concomitant temporal decline of the yields of unstable dicentrics or the statistical analyses of the data and their implications for quantifying low-level radiation exposure will be discussed in this report.

Chromosome Aberrations↗
PubMed1995

Automated metaphase finding: an assessment of the efficiency of the METAFER2 system in a routine mutagenicity assay.

The efficiency of the automated metaphase finding system METAFER2 is assessed in a routine mutagenicity assay using an aneuploid rat liver cell line treated with various promutagens. Data sets generated by automated and manual selection of metaphases are compared. It is demonstrated that METAFER2 routinely allows an efficient automatic identification of metaphases not only in lymphocyte preparations, but also in preparations from mammalian cell lines with varying chromosome numbers. Although larger slide areas are required for automated compared to manual metaphase scanning, the automatic system is faster by a factor of about 5. The interactive visual elimination of metaphases of insufficient quality is an easy and fast procedure. METAFER2 allows an unbiased selection of metaphases irrespective of their appearance as homogeneously stained first or harlequin-stained second division cells. Random selection of metaphases is neither influenced by various structural chromosome changes nor by increased frequencies of sister-chromatid exchanges.

Aneuploidy↗
PubMed1995

Effect of activated oxygen species in human lymphocytes.

The cytogenetic effectiveness of activated oxygen species (AOS) generated by the superoxide forming xanthine-xanthine oxidase (X/XO) system was studied in human lymphocyte cultures. The observed chromosome damage was exclusively of the chromatid type. In the experiments a clear dependence of aberration induction on XO concentration and exposure time could be demonstrated. While using anti-AOS agents, the H2O2 antagonist catalase and the hydroxyl radical scavenger formate reduced X/XO induced chromosome damage whereas superoxide dismutase (SOD) did not. In the presence of SOD, aberration frequency was even enhanced. The results indicate that the chromosome damage is caused indirectly via H2O2 formation from spontaneous dismutation of superoxide, whereas H2O2 might be reduced intracellularly giving rise to the highly reactive hydroxyl radical. This effect might be enhanced by SOD, possibly by raising the intracellular amount of easily membrane passing H2O2. Thus, referring to chromosome aberrations, SOD, which is generally reported to protect from AOS, is capable of increasing oxygen mediated biological damage. This observation might be explained by the involvement of DNA associated transition metal, like iron or copper ions, in reducing H2O2. DNA bound copper ions, thought to be necessary for maintenance of DNA quaternary structure, might represent a generator complex for the hydroxyl radical by reduction of X/XO derived hydrogen peroxide. This might cause 'site specific damage' to the DNA which is subsequently converted into chromatid-type aberration by S-dependent misreplication and/or misrepair. This is different to the formation of radiation induced chromosome aberrations which arise by an S-phase independent mechanism.

Antioxidants↗
PubMed1995

Combined FISH painting and harlequin staining for cell cycle-controlled chromosome analysis in human lymphocytes.

We present a simple method that allows scoring of FISH-painted chromosomes exclusively in the first division human lymphocytes. It consists of a combination of FISH with chromosome-specific libraries and a differential sister chromatid staining after BrdU treatment of lymphocyte cultures. The method allows a precise quantification of induced chromosome damage for human biodosimetry.

Cell Cycle↗
PubMed1995

Chromosome painting in highly irradiated Chernobyl victims: a follow-up study to evaluate the stability of symmetrical translocations and the influence of clonal aberrations for retrospective dose estimation.

Follow-up fluorescence in situ hybridization (FISH) measurements of symmetrical translocations were performed in peripheral blood lymphocytes from 12 highly irradiated victims of the Chernobyl nuclear power plant accident biannually, between September 1991 and July 1994, to investigate the persistence of these aberration type with time post-exposure. Translocations were determined using biotin-labelled painting DNA probes for human chromosomes 1, 4 and 12 and a digoxigenin-labelled alpha-satellite pancentromeric DNA probe. In 11 of 12 cases the translocation frequencies remained fairly constant during the observation period, which allows to generate comparable dose estimates on the various sampling times. In one case (no. 9) the existence of a cell clone containing the consistent chromosome rearrangement t(1;13) (q25;q14) was identified using FISH in rehybridized slides with a digoxigenin-labelled painting DNA probe for chromosome 13 and a separate G-banding analysis. To obtain reliable dose estimates, total translocation frequency has to be corrected for the high contribution (16.5-23.5%) of this clonal translocation.

Accidents↗