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M Kirsch-Volders

Publications and source records attributed to M Kirsch-Volders.

At least 73 records · Page 4Linked to original sources
PubMed1995

In vitro effects of therapeutic ultrasound on the nucleus of human fibroblasts.

BACKGROUND AND PURPOSE: The purpose of this investigation was to examine the cytological effects of therapeutic ultrasound on human fibroblasts. MATERIAL AND METHODS: Using an in vitro approach, the number of cells recovered, the morphology of chromosomes, and the presence of mitotic spindles were studied after sonication of human fibroblasts in culture. The ultrasound output had a frequency of 1 MHz and was delivered in a pulse mode of 2 milliseconds "on" and 8 milliseconds "off." Sonication was given for 0, 30, 60, and 90 seconds. RESULTS: There was a time-dependent decrease in number of cells recovered, a fourfold increase in mitotic index in the cells that survived the treatment, and a nearly eightfold increase of chromosomal aberrations with loss of mitotic spindles. CONCLUSION AND DISCUSSION: The dose-dependent lytic effect of nonthermal ultrasound could result in fractionation of cells, which might facilitate phagocytosis during chronic inflammation. In addition, we observed an increase in chromosomal aberrations and a loss of mitotic spindles as a result of an extremely short ultrasound treatment (30 seconds). Whether these alterations are mutagenic or not warrants further study. It is possible that in our in vitro experiments, the ultrasound received was greater than would occur in a clinical situation.

Cells, Cultured↗
PubMed1994

Cytogenetic analysis of lymphocytes from fiberglass-reinforced plastics workers occupationally exposed to styrene.

In this study a group of 52 workers employed in a plant manufacturing fiberglass-reinforced plastic (FRP) pipes and cisterns, and therefore daily exposed to styrene, were monitored. As a control group 24 non-exposed workers from another factory producing and repairing pallets volunteered to participate. The airborne styrene during the monitoring ranged from 2.2 to 110.1 mg/m3. As a metabolic marker for styrene exposure mandelic acid was measured in the urine and ranged from 11 to 649 mg/g creatinine. From 43 exposed and 15 control workers sister-chromatid exchanges (SCE) and high frequency cell (HFC) data and from 49 exposed and 23 control workers micronucleus (MN) data from peripheral lymphocytes are reported. Although the two groups of workers could clearly be distinguished on the basis of the airborne styrene concentrations and urinary mandelic acid concentrations no differences in any of the cytogenetic markers were found. Correlations between the cytogenetic data and the level of airborne styrene concentrations or urinary mandelic acid levels could also not be demonstrated. Otherwise, smoking increased the SCE frequency. Grouping the workers according to smoking habits showed a statistically significant difference in SCE. Moreover, levels of urinary thiocyanate (SCN), which can be used as a metabolic marker for smoking, showed a significant positive correlation with the number of SCE. This indicates that SCE is a sensitive biomarker and might still be useful in biomonitoring. However, only chronic exposures over a long period would probably be detectable. In this study, where exposure was rather low and the number of working years was small (mean of 2.9 years), cytogenetic effects are probably too low or rare to be detectable with any assay.

Adult↗
PubMed1994

Detection of premalignant stages in cervical smears with a biotinylated probe for chromosome 1.

Fluorescence in situ hybridization with (peri-)centromeric probes is an easy method to detect numerical aberrations in nonmitotic and mitotic cells. In this study, cervical smears of premalignant and malignant stages (26 controls, 15 CIN I, 12 CIN II, and 15 CIN III cervical smears) were analyzed for the presence of numerical aberrations of chromosome 1 with a centromeric DNA probe (1q12). With more severe stages a decrease of disomy was observed, merely due to a gain of extra copies of chromosome 1; in some cases, however, monosomy was detected. The frequencies of disomy for chromosome 1 ranged from 65.3% to 95.0% in the controls, from 71.3% to 94.3% in CIN I, from 59.2% to 91.5% in CIN II, and from 23% to 96.2% in CIN III. Polysomy ranged from 0% to 5.7% in the controls, from 0% to 14.4% in CIN I, from 0.9% to 30.8% in CIN II, and from 0.8% to 69.6% in CIN III. Monosomy ranged from 2.6% to 34.1% in the controls, from 0% to 17.5% in CIN I, from 3.6% to 27.5% in CIN II, and from 0.9% to 31.4% in CIN III. The results show that screening for aneuploidy of chromosome 1 allows a good discrimination between control samples and dysplasia. These data suggest that chromosome 1 may be a marker chromosome. They are in accordance with previous cytodensitometric analyses, where already in the preneoplastic stages an increased DNA content (polyploidization with subsequent aneuploidization) is observed.

Adult↗
PubMed1994

Report from the working group on the in vivo mammalian bone marrow chromosomal aberration test.

The following summary represents a consensus of the working group, except where noted. The goal of this working group was to identify the minimal requirements needed to conduct a scientifically valid and practical in vivo chromosomal aberration assay. For easy reference, the items discussed are listed in the order in which they appear in OECD guideline 475. Specific disagreement with the current and/or proposed OECD guideline is presented in the text. Introduction, purpose, scope, relevance, application, and limits of test: This test would not be appropriate in situations where there was sufficient evidence to indicate that the test article or reactive metabolites could not reach the bone marrow. Test substances: Solid and liquid test substances should be dissolved, if possible, in water or isotonic saline. If insoluble in water/saline, the test substance should be dissolved or homogeneously suspended in an appropriate vehicle (e.g., vegetable oil). A suspension was not considered suitable for an intravenous injection. The use of dimethyl sulfoxide as an organic solvent was not recommended. The use of any uncommonly used solvent/vehicle should be justified. Freshly prepared solutions or suspensions of the test substance should be employed unless stability data demonstrate the acceptability of storage. Selection of species: Any commonly used rodent species was deemed acceptable but rats or mice were preferred, with no strain preference. Number and sex: A consensus could not be reached as to the requirement for both sexes versus one sex in this assay. It was suggested that a single sex should be used unless pharmacokinetic and/or toxicity data indicated a difference in metabolism and/or sensitivity between males and females. The size of the experiment (i.e., number of cells per animal, number of animals per treatment group) should be based on statistical considerations. Lacking a formal analysis, it was agreed that at least 100 metaphase cells should be scored per animal while at least five animals of any one sex should be evaluated per treatment group. Recently, a formal analysis of the numbers of cells to score per animal and numbers of animals to score per treatment group was conducted at a workshop on statistics for in vivo mutagenicity tests (Adler et al., 1994). The conclusion of this workshop was that, based on a type I error of 0.05 and a power of 80% to detect at least a doubling in the control frequency, the minimal number of cells to score per animal was 200 and the minimal number of animals to score per sex per treatment group was four.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Aneuploidy for chromosome 1 and overall DNA content in benign and malignant breast disease.

Fluorescence in situ hybridization (FISH) with a probe for the pericentromeric region of chromosome 1 and DNA content measurements by image-analysis-based densitometry have been carried out on imprints of benign and malignant breast tissue. In general, an increase in the number of spots per nucleus was observed in the invasive carcinomas, with a large intercellular variation. In comparison with lymphocytes from controls, some cases of benign breast disease already had an increased frequency of aneusomy of chromosome 1, although they were all (near)diploid by DNA-content. However, an overall concordance between the DNA content measurements and the results of FISH was observed, although some exceptions were seen. A statistically significant correlation between the DNA index and the mean number of spots for chromosome 1 per nucleus was found. A linear discriminant analysis was applied on the data; the resulting classification of patients was most accurate when parameters describing DNA content and FISH results were combined.

Aneuploidy↗
PubMed1994

Metabolic differences between whole blood and isolated lymphocyte cultures for micronucleus (MN) induction by cyclophosphamide and benzo[a]pyrene.

In order to study the metabolic differences between whole blood and isolated lymphocyte cultures, two indirectly acting mutagens cyclophosphamide (CP) and benzo[a]pyrene (B[a]P) were assessed for their potential to induce micronuclei (MN) in the presence and absence of S9 microsomal fractions. In isolated lymphocyte cultures supplemented with S9, CP and B[a]P induced a statistically significant increase in MN which was not observed in whole blood cultures. However, the direct-acting agent methyl methanesulphonate (which was used as a positive control) showed an increase in MN frequency in a dose-dependent manner in both culture methods. The effect of erythrocytes was then investigated by treating isolated lymphocyte cultures simultaneously with CP and S9 mix in the presence of purified erythrocyte concentrate (PEC). A clear reduction in the MN frequency was observed compared to the frequencies of MN induced in isolated lymphocyte cultures treated with CP and S9 mix in the absence of PEC. Thus, isolated lymphocyte cultures may represent a more sensitive test system for the evaluation of potential indirect-acting mutagens. However, whole blood cultures may reflect the 'real life' situation more accurately as a consequence of the presence of erythrocytes.

Adult↗
PubMed1994

Urinary mandelic acid and hemoglobin adducts in fiberglass-reinforced plastics workers exposed to styrene.

OBJECTIVES: A field study was undertaken to investigate the effects of occupational styrene exposure on mandelic acid excretion and the formation of styrene-7,8-oxide hemoglobin adducts. Especially the sensitivity of a gas chromatography-mass spectrometry method for determining hemoglobin adducts was evaluated. METHODS: Over a four-week period, each individual of a group of 52 fiberglass-reinforced plastics workers was monitored once a week by the simultaneous measurement of styrene in the air and urinary postshift mandelic acid. In addition mandelic acid and hemoglobin adducts were monitored in a group of 24 unexposed referents. At the end of the monitoring period styrene-7,8-oxide adduct formation on N-terminal valine in hemoglobin was examined by gas chromatography-mass spectrometry according to the modified Edman degradation technique. RESULTS: Personal air samples showed an average styrene exposure of 31 mg.m-3. The average postshift mandelic acid was 98 mg.g creatinine-1. For workers not wearing respirators and not showing breath ethanol, the correlation coefficient between styrene and mandelic acid was 0.78. The blood samples were analyzed for styrene-7,8-oxide adducts on hemoglobin. With a detection limit of 10 pmol.g-1, no styrene-7,8-oxide adducts were found under these exposure conditions. CONCLUSION: Adduct formation in humans is less effective than in mice. In comparison with ethylene, styrene is at least 70 times less effective in forming hemoglobin adducts. Investigating adduct formation in humans at or below the exposure levels reported in this study would require a detection limit of about one order of magnitude better.

Adult↗
PubMed1993

Biological markers in PAH exposed workers and controls.

Workers employed in a graphite electrode producing plant (n = 16) and a coke oven (n = 33) were compared with a control population of maintenance workers in a blast furnace (n = 54). The following parameters were analyzed: concentration of 13 different PAHs in the work environment measured by personal air samplers, concentration of hydroxypyrene in the urine, smoking habits (via urinary thiocyanate levels and a questionnaire) and cytogenetic aberrations in lymphocytes (SCE, HFC and MN). On the basis of PAH levels in the work environment and hydroxypyrene concentrations in the urine, the workers from the graphite electrode producing plant were the most exposed. However, statistically significant differences in SCE and HFC and positive correlations between the cytogenetic markers and airborne PAH levels on the one hand, and urinary hydroxypyrene concentrations on the other hand were only detectable in the workers from the coke oven with a lower exposure. No statistically significant effect of smoking was observed. As to the inter-comparison of the different cytogenetic markers, one may consider that SCE and HFC are more sensitive than MN frequencies for the biomonitoring of exposure to PAHs. Whether MN or SCE are the best biomarker for risk assessment of cancer and whether the presence of PAHs in the work environment is really responsible for the cytogenetic effects found in this study could not be ascertained.

Air Pollutants, Occupational↗
PubMed1993

Induction of micronuclei and karyotype aberrations during in vivo mouse skin carcinogenesis.

The induction of chromosome and/or genome mutations during the first steps of skin carcinogenesis was followed in male NMRI mice, treated with a 'two-stage' [9,10-dimethyl-1,2-benzanthracene (DMBA) + phorbol-12-myristate-13-acetate (TPA)], or a 'three-stage' [DMBA+methyl methanesulphonate (MMS) + phorbol-12-retinoate-13-acetate (RPA)] protocol. The scoring of micronuclei (MN) in basal and suprabasal keratinocytes allows a relatively fast in vivo estimation of clastogenic and aneugenic effects of various compounds and treatments. Relevant stages were then further analysed by karyotyping the in vivo treated keratinocytes that were allowed to divide during short in vitro cultivation. DMBA used as initiator in both protocols was able to induce MN. The well-known clastogen MMS had an acute but transient effect on MN induction when used alone or as convertor in the three-stage protocol. Neither the propagator RPA, nor the 'full-promotor' TPA, which can carry out conversion as well as propagation, induced statistically significant numbers of MN when applied on mouse skin. Combined treatments, DMBA+MMS and MMS+RPA, showed higher MN frequencies than when MMS treatments were given alone. The full carcinogenic protocols showed significant frequencies of MN but the time points of appearance differed, indicating that the accumulation of aberrations could be more important than the order of appearance. Karyotypic analysis of those stages where the MN assay detected genome and/or chromosome aberrations revealed no specific loss of chromosomes that might be directly related to the carcinogenic process. When chromosome loss and aberrations were both taken into consideration together, chromosomes 7 and 11 and surely 9, 17 and 18 were more frequently involved than others.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

Frequency and DNA content of micronuclei in rat parenchymal liver cells during experimental hepatocarcinogenesis.

Liver carcinogenesis is considered to be a good experimental model to study the sequential changes leading to cancer and was applied here for the analysis of chromosome/genome mutations. Since the micronucleus test was shown to be an adequate method to detect and analyse chromosome changes in dividing cells, the frequency of micronuclei (MN) together with their relative DNA content (DNA content of the MN divided by the DNA content of the corresponding nucleus) were analysed in hepatocytes isolated from rats at different stages of experimentally induced hepatocarcinogenesis. The protocol used for the induction of liver cancer was based on the triphasic 'Gerlans protocol', a Solt-Farber procedure supplemented with a phenobarbital (PB) promotion step. Male Wistar rats were initiated by a single i.p. dose of diethylnitrosamine (DENA), followed by selection of the resistant hepatocytes by 2-acetylaminofluorene (2-AAF). Subsequent promotion was accomplished by chronic exposure to phenobarbital. For each group of rats a mitotic stimulator (CCl4) is necessary at the end of their treatment period to express the clastogenic and/or aneugenic lesions which may lead to micronuclei. The results of these experiments do confirm that genetic alterations are occurring at the chromosome level (MN expression) during the different steps of experimental rat liver carcinogenesis. DNA measurements seem to be a good genetic parameter to detect eventual differences between the chromosomal content (whole chromosome or chromosome fragments) of MN populations appearing in different stages of the carcinogenic process. Moreover, a comparison between the mono- and bi-nucleated cell population showed that the frequency of micronuclei is higher in mononuclear parenchymal liver cells.

2-Acetylaminofluorene↗
PubMed1993

Automated detection of cytochalasin-B blocked binucleated lymphocytes for scoring micronuclei.

A comparison between manual and computer-based automatic scoring of micronuclei (MN) was performed in order to optimize the preparation technique and to validate the image analysis procedure. For this purpose whole human blood of three donors was either irradiated (1 Gy X-rays) or treated with the chemical mutagen methyl methane sulphonate (25 mg/ml) and cultivated in the presence of cytochalasin B to obtain binucleated cells with a high yield of MN. An algorithm for MN detection has been developed for Giemsa (G)- and Feulgen-Congo-Red (FCR)-stained slides. This algorithm contains a sequence of grey operators and binary operators necessary to detect nuclei and MN, and to efficiently reject artefacts. The output is a data file with measurements of cells and intracellular inclusions. From these features, information can be extracted concerning the frequency of the various cell classes (based on nuclearity), the presence of MN and various shape parameters. A close analysis of the automatic scoring of G- and FCR-stained cells, revealed that 59-86% of all automatically classified binucleated cytokinesis-blocked (CB) cells were correctly classified. Although some MN were overlooked during automated scoring, the results show that, on average, similar MN frequencies are obtained with automated and manual scoring. The errors which occurred were mainly due to the misclassification of CB cells, the non-detection of extremely small MN and the aggregation of MN to the main nucleus. The possibility of scanning high numbers of cells overnight, to relocate CB cells with potential MN and the quantitative character of the results offers good prospects for future use in the in vitro MN test.

Adult↗
PubMed1993

Comparative mutagenicity of structurally related aliphatic epoxides in a modified Salmonella/microsome assay.

Four structurally related aliphatic epoxides (1,2-epoxypropane, 1,2-epoxyisobutane, cis- and trans-2,3-epoxybutane) have been tested in the Salmonella/microsome assay, modified for volatile substances, using the strains TA1535 and TA100. The aim of the study was to evaluate the effect of methylation on the mutagenicity of 1,2-epoxypropane in this vaporization assay, with and without exogenous metabolization. All substances induced a significant increase of revertants in the strains TA1535 and TA100. In terms of mutagenic potency, the following hierarchy was observed in the standard tester strain TA1535 and in the absence of rat S9: 1,2-epoxy-propane >> cis-2,3-epoxybutane > 1,2-epoxyisobutane > trans-2,3- epoxybutane. After exogenous metabolization, the mutagenic response of 1,2-epoxyisobutane was substantially reduced, while a moderate decrease of cis-2,3-epoxybutane was observed in the presence of S9, as compared with the response without S9. No influence of the S9 on the mutagenic response of trans-2,3-epoxybutane was noticed in both strains TA1535 and TA100, while an increased response with 1,2-epoxypropane was observed in TA100 but not in TA1535. The results suggest that the vaporization assay may provide more relevant information concerning mutagenic potencies of gaseous or volatile compounds than the common treat-and-plate or preincubation assays. Moreover, it appears that mutagenicity theories, based only upon inductive effects of side groups, may not suffice to explain differences in mutagenicity. Sterical factors or differential interactions with metabolizing enzymes could also be important in the evaluation of mutagenic effects.

DNA, Bacterial↗
PubMed1992

Mutagenicity of 2-methylpropene (isobutene) and its epoxide in a modified Salmonella assay for volatile compounds.

The mutagenic properties of 2-methylpropene (MP) and 2-methyl-1,2- epoxypropane (MEP) were investigated in the Salmonella assay. A simple exposure system, consisting of gastight tissue culture flasks, was used. This method has the advantage that the volatile test chemical is present during the entire incubation period and that several concentrations of the investigated compound can be tested on a single day. MP is not mutagenic in strains TA100, TA102 and TA1535, and in the latter strain not even in the presence of metabolizing S9 mix. MEP is mutagenic in all the strains tested, as demonstrated by a clear dose-response relationship. Strain TA1535 seems to be most sensitive to MEP compared with the other bacterial strains studied. For this strain, the mutagenic activity of MEP decreased significantly in the presence of S9 mix, compatible with the epoxide being inactivated by epoxide hydrolase and by glutathione S-transferase, as reported previously. From the present study it can be concluded that the parent compound MP is not mutagenic, but that its primary metabolite MEP is a mutagenic substance. However, very high concentrations are necessary to induce a mutagenic effect and the epoxide is efficiently detoxified by different liver enzymes.

Alkenes↗
PubMed1992

Discrimination of aneuploidogens from clastogens by C-banding, DNA and area measurements of micronuclei from mouse bone marrow.

Micronuclei (MN) obtained from mouse bone marrow cells, in vivo exposed to 3 typical clastogens (procarbazine, azathioprine, ethyl methanesulfonate) and 3 typical aneuploidogens (vinblastine, tubulazole, colchicine), were examined for C-band, area and DNA content. C-banding allows a clear discrimination between clastogens and aneuploidogens: the clastogens do not exceed 50% C-band-positive MN and the aneuploidogens all 3 produce 65-75% C-band-positive MN. Concerning the DNA content the percentages of MN containing more DNA than an average chromosome (chr) are lower than 12% for the clastogens and 38-60% for the aneuploidogens. As far as the area of the MN is concerned the percentages of MN which have a larger area than chr are lower than 23% for the clastogens and range from 47% to 71% for the aneuploidogens. Additionally 3 other mutagens were studied. Hydroquinone induces 43% C-band-positive MN with DNA content far below the content of chr; considering the area measurements, however, hydroquinone behaves as an aneuploidogen (65% of the MN are larger than chr). Mitomycin C lies between the clastogens and the aneuploidogens for all 3 criteria but 5-azacytidine is comparable to the model aneuploidogens.

Aneuploidy↗
PubMed1992

Comparison of 32P-postlabelling and cytogenetic analysis of human blood treated in vitro with melphalan.

Various 32P-postlabelling methods have been evaluated for the detection of melphalan-DNA (mel-DNA) adducts in melphalan treated calf thymus DNA and human blood treated in vitro with melphalan. When the butanol extraction procedure was used for the postlabelling studies, increasing adduct levels were seen between 0.01 and 1.0 micrograms/ml melphalan (maximum adduct value = 3.29/10(8) nucleotides at 1.5 micrograms/ml melphalan). The labelling efficiency, however, was thought to be low. Human blood treated in vitro with a dose range of melphalan from 0.01 to 1.5 micrograms/ml was analysed for micronuclei, sister chromatid exchanges, chromosome aberrations and DNA adducts. A correlation was seen between mel-DNA adducts and cytogenetic damage for each of the endpoints studied.

Animals↗
PubMed1992

Analysis of eight known or suspected aneugens by the in vitro human lymphocyte micronucleus test.

In the light of the CEC aneuploidy programme eight known or suspected aneugens were evaluated with the human lymphocyte 'in vitro' micronucleus test using the cytochalasin-B technique. Only colchicine, chloral hydrate and hydroquinone induced dose-dependent increases in micronucleus frequencies. The other five chemicals (cadmium chloride, econazole, pyrimethamine, thiabendazole and thimerosal) were all negative, both with and without S9, and treated in G1 or G2 phase. These data are in good agreement with results from different 'in vivo' studies. However, discrepancies were found between the results from this study of human lymphocytes and those of other cultured cell types where econazole, cadmium chloride, pyrimethamine and thiabendazole induce a significant increase of micronuclei.

Adult↗
PubMed1991

Mouse micronucleus tests with known and suspect spindle poisons: results from two laboratories.

Micronucleus assays were carried out independently in two laboratories with 10 chemicals selected for aneuploidy studies in a coordinated project supported by the CEC. All chemicals were distributed from a single batch by the project coordinator. Male and female mice were treated by single i.p. injections, bone marrow was sampled 6, 24 and 48 h after treatment. Polychromatic and normochromatic erythrocytes were evaluated for the presence of micronuclei after May--Grünwald/Giemsa or Wright staining. The results from both laboratories are in close agreement even though different stocks of mice and different sample sizes were employed in the two laboratories. Only three of the 10 compounds induced micronuclei in mouse erythrocytes: colchicine, hydroquinone and vinblastine. The other seven chemicals gave negative results: econazole, chloralhydrate, diazepam, thiabendazole, cadmium chloride, thimerosal and pyrimethamine. The negative results for econazole and chloralhydrate were unexpected in light of the fact that these two chemicals were previously shown to increase the mitotic index and to induce c-mitotic effects in mouse bone marrow cells. The need for further investigations of these compounds by chromosome counting in second post-treatment metaphases is emphasized to determine their ability to induce aneuploidy.

Aneuploidy↗