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L Verschaeve

Publications and source records attributed to L Verschaeve.

At least 37 records · Page 2Linked to original sources
PubMed1998

Genetic, carcinogenic and teratogenic effects of radiofrequency fields.

This paper reviews the literature data on the genetic toxicology of radiofrequency (RF) radiation. Whereas in the past most studies were devoted to microwave ovens and radar equipment, it is now mobile telecommunication that attracts most attention. Therefore we focus on mobile telephone frequencies where possible. According to a great majority of the papers, radiofrequency fields, and mobile telephone frequencies in particular, are not genotoxic: they do not induce genetic effects in vitro and in vivo, at least under non-thermal exposure conditions, and do not seem to be teratogenic or to induce cancer. Yet, some investigations gave rather alarming results that should be confirmed and completed by further experiments. Among them the investigation of synergistic effects and of possible mechanisms of action should be emphasised.

Abnormalities, Drug-Induced↗
PubMed1997

Cytogenetic effects of 935.2-MHz (GSM) microwaves alone and in combination with mitomycin C.

This paper focuses on the genetic effects of microwaves from mobile communication frequencies (935.2 MHz) alone and in combination with a chemical DNA-damaging agent (mitomycin C). Three cytogenetic endpoints were investigated after in vitro exposure of human whole blood cells. These endpoints were the 'classical' chromosome aberration test, the sister chromatid exchange test and the alkaline comet assay. No direct cytogenetic effect was found. The combined exposure of the cells to the radiofrequency fields followed by their cultivation in the presence of mitomycin C revealed a very weak effect when compared to cells exposed to mitomycin C alone.

Chromosome Aberrations↗
PubMed1997

The VITOTOX test, an SOS bioluminescence Salmonella typhimurium test to measure genotoxicity kinetics.

A new test to detect genotoxicity, that we refer to as the VITOTOX test, was developed. Four gene fusions that are based on the Escherichia coli recN promoter were constructed and evaluated for their SOS response-dependent induction. The wild-type recN promoter, a derivative mutated in the second LexA binding site, a derivative with a mutated -35 region, and a derivative from which both the second LexA binding site and the -35 region were mutated, were cloned upstream of the promoterless Vibrio fischeri luxCDABE operon of pMOL877, in such a way that lux became under transcriptional control of the recN promoter derivatives. The inducibility by the SOS response of the promoter constructs was tested in both E. coli and in the Ames test Salmonella typhimurium strains TA98, TA100 and TA104. In all strains, the highest sensitivity and induction was observed with the plasmids pMOL1067 and pMOL1068, that contain the lux operon under control of the recN promoter mutated in the second LexA binding site, or a recN promoter with a mutated -35 region, respectively. Therefore, strains containing pMOL1067 or pMOL1068 were further used for genotoxicity testing. With the VITOTOX test, genotoxicity was detected within 1-4 h. The VITOTOX test is very sensitive: for most products tested, the minimal detectable concentration (MDC) values were considerably lower (5 to > 100 times) than those described for the Ames test and the SOS chromotest. A good correlation was observed with the results from the Ames tests, but certain PAHs that are not mutagenic in the Ames test were genotoxic in the VITOTOX test. With the VITOTOX strains, the kinetics of SOS induction can be determined. This feature made it possible to distinguish between compounds in mixtures of genotoxic products so long as they had different induction kinetics.

Bacterial Proteins↗
PubMed1997

The cell cycle positions influence DNA migration as measured with the alkaline comet assay in stimulated human lymphocytes.

Virtually any eukaryotic cell can be processed for analysis of DNA damage using the comet assay. The most commonly examined human cells are lymphocyte populations. However, many parameters can affect the response of lymphocytes to the assay in terms of the ability to detect damage. The response of cultivated lymphocytes in the comet assay indicated cycle-dependent differences. The cell cycle position has been shown to affect the results obtained using both the alkaline and neutral assays. This is primarily a reflection of the complications of including S-phase DNA. In the alkaline assay, replicating structures are interpreted as strand breaks when denatured, increasing the level of detectable damage. We performed the alkaline comet assay to detect differences in the extent of DNA in stimulated human lymphocytes collected at different sample times after mitogen stimulation. Our results clearly indicate that proliferating lymphocytes have a greater migration of DNA (measured with the comet assay as DNA damage) than quiescent lymphocytes. The lymphocytes collected at 36, 42, and 48 h after mitogen stimulation showed a significantly increased extent of DNA migration in comparison to the lymphocytes collected at 0 and 24 h after stimulation. It, probably, can be explained by the higher frequency of the S phase cells in lymphocyte populations collected at 36, 42, and 48 h. Sites of active DNA replication during the S phase behave like single-strand breaks when denatured in alkali, and their presence may result in a significant increase of the tail moments in S phase cells.

Adult↗
PubMed1996

The alkaline comet test on plant cells: a new genotoxicity test for DNA strand breaks in Vicia faba root cells.

The alkaline comet assay (single cell gel electrophoresis assay) is a sensitive method for the detection of DNA damage. This paper describes the first application of this assay to plant cells for genotoxicological assessment. Germinating Vicia faba (field bean) seedlings were kept in water with either methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), mitomycin C (MMC), cycloheximide (CH), cadmium chloride (CdCl2), potassium dichromate (K2Cr2O7), or chromium trichloride (CrCl3). Nuclei were isolated from the root cells and evaluated for the extent of DNA migration. With the exception of cycloheximide, all agents induced a significant increase in DNA migration. These results indicate that the comet assay may be a valuable tool for monitoring DNA damage in plant systems. However, there was a significant heterogeneity in the extent of DNA migration within and between seedlings, which may be intrinsic to the assay or indicative of sampling problems.

Cadmium↗
PubMed1996

954 MHz microwaves enhance the mutagenic properties of mitomycin C.

This paper focuses on the combined effects of microwaves from mobile communication frequencies and a chemical DNA damaging agent mitomycin C (MMC). The investigation was performed in vitro by exposing whole blood samples to a 954 MHz emitting antenna from a GSM (Global System for Mobile Communication) base station, followed by lymphocyte cultivation in the presence of MMC. A highly reproducible synergistic effect was observed as based on the frequencies of sister chromatid exchanges in metaphase figures.

Cell Cycle↗
PubMed1996

The comet assay for the detection of genotoxic damage in the earthworms: a promising tool for assessing the biological hazards of polluted sites.

The comet assay, a relatively new method for DNA strand break detection in individual cells, is becoming a major tool for environmental biomonitoring. One approach for assessing the possible environmental consequences of hazardous waste pollution involves the assessment of genotoxic damage (and other effects) in sentinel organism. The single cell gel electrophoresis (SCGE) technique or comet assay. because of its simplicity, sensitivity, and need for only small numbers of cells, has been suggested as an ideal technique for such studies. An important advantage of the technique is that it is applicable to any eukaryotic organism and cell type. Verschaeve et al. (1993) conducted a pilot study using alkaline comet assay to assess the extent of DNA damage in coelomic leucocytes (coelomocytes) of earthworms (Eisenia foetida) maintained in different soil samples as an indicator of soil pollution. The aim of our study was to evaluate the usefulness of monitoring single strand breaks in coelomocytes for assessing genotoxicity of pollutants in coke oven area. We exposed earthworms to samples of soils obtained from polluted areas of a coke oven. All samples gave a significantly higher comet tail moment that those obtained from worms kept in laboratory conditions (standard black earth = internal controls) and worms kept in soils from control areas (= external controls). Our results show that the comet assay applied to earthworm is very valuable for monitoring and detection of genotoxic compounds in terrestrial ecosystems.

Animals↗
PubMed1993

In vitro cytogenetic effects of 2450 MHz waves on human peripheral blood lymphocytes.

Cytogenetic analyses were performed on human peripheral blood lymphocytes exposed to 2450 MHz microwaves during 30 and 120 min at a constant temperature of 36.1 degrees C (body temperature). The temperature was kept constant by means of a temperature probe put in the blood sample which gives feedback to a microcomputer that controls the microwave supply. We found a marked increase in the frequency of chromosome aberrations (including dicentric chromosomes and acentric fragments) and micronuclei. On the other hand the microwave exposure did not influence the cell kinetics nor the sister chromatid exchange (SCE) frequency.

Adult↗
PubMed1993

Stable chromosome aberrations 25 years after severe accidental radiation exposure.

A thorough cytogenetic analysis using G-banding was performed on 100 peripheral blood lymphocytes from an individual who had been accidentally exposed to radiation more than 25 years previously. More than 60% of the analysed cells were found to possess one or more stable chromosome aberrations (e.g. reciprocal translocations). Chromosomes 1 and 11 were more involved in these aberrations than would be expected from the relative chromosome lengths. No identical stable aberrations were found, suggesting that, 25 years after near-lethal exposure, haemopoietic stem cells display substantial diversity.

Accidents↗
PubMed1993

Chromosome aberrations in inhabitants of Byelorussia: consequence of the Chernobyl accident.

A cytogenetic analysis was performed on peripheral blood lymphocytes from 35 persons belonging to the 'general population' of Gomel or its surroundings (Byelorussia). This region was heavily contaminated by the nuclear fall-out following the radiation accident at Chernobyl. An elevated frequency of chromosome aberrations was found in most of the subjects. The type and frequency of the aberrations revealed past and possibly present radiation exposure which could be ascribed to the accident at the Chernobyl nuclear plant about 5 years prior to the analysis.

Accidents↗
PubMed1993

Mixed phenotype murine leukemias.

Cell lines were derived from eight individual leukemias induced by X-rays in NFS mice. First typed as null cells (surface immunoglobulin negative, Thy-1 negative), they turned out to have a mixed phenotype with myeloid cytochemical markers, pre-B surface antigens and molecular markers of pro-B lymphocytes. They represent murine models for mixed phenotype (pro-pre-B-myeloid) leukemias.

Animals↗
PubMed1993

Influence of blood storage after in vitro exposure on the yield of micronuclei observed in human lymphocytes.

In a cooperative study, four laboratories evaluated the micronucleus test in irradiated and non-irradiated lymphocytes with respect to time of storage, the difference between X-ray and gamma exposure and inter-observer variance. The results were compared with parallel studies on dicentric aberrations. No significant differences between laboratories, with respect to storage time or between gamma and X-irradiation were observed for micronuclei and dicentrics using analysis of variance. However, micronuclei are not suitable for an assessment of exposure inhomogeneity because of a significant overdispersion already in controls and homogeneously irradiated samples.

Belgium↗
PubMed1992

Chromosomal aberrations in human lymphocytes induced in vitro by very low doses of X-rays.

This paper presents results of a collaborative experiment between six laboratories which examined the yields of unstable chromosomal aberrations in human lymphocytes induced in vitro by X-rays over the dose range 0-300 mGy. The work included data points of nominal doses of 0, 3, 5, 6, 10, 20, 30, 50 and 300 mGy. Cells from 24 donors were examined and a total of about 300,000 metaphases were scored. The work was undertaken to determine the limits of sensitivity of the system taking into account variations in scoring data due to inter-donor sample and inter-laboratory effects. Despite the existence of these effects, aberration yields significantly in excess of control values were seen at doses greater than 20 mGy and these were consistent with a linear extrapolation from higher doses. Below 20 mGy the observed dicentric yields were generally lower than background, but not significantly so. Excess acentric aberrations, on the other hand, and centric rings, were higher than the controls but the increase was usually not significant. It is concluded that the statistical uncertainties are such that below 20 mGy this technique cannot distinguish between a linear or a threshold model.

Chromosome Aberrations↗
PubMed1989

Suggestive evidence that genes controlling invasion and metastasis of T-cell lymphomas are located on mouse chromosome 3.

Cell lines differing in their malignant potential have been derived from the murine BW5147 T-cell lymphosarcoma. To evaluate the involvement of chromosomal aberrations in tumor progression within this model, we have analyzed the karyotypes and the in vitro invasiveness of 13 related nonmetastatic and metastatic variants. Giemsa banding revealed the presence of several marker chromosomes, one of which was of particular importance. Depending on the cell line, four variants of this marker I were found: Marker Ia corresponds to two translocated chromosomes 3, marker Ib is a deleted Ia marker, marker Ic is a Ib translocated to small unidentified chromosome fragment, and marker Id is a further deleted Ib marker. The Ia and Id markers were characteristic for the noninvasive, nonmetastatic lines, whereas the Ib and Ic markers predominated in the invasive, metastatic variants. The results suggest that metastasis-enhancing genes are located between the D and FI band of mouse chromosome 3 and that metastasis-suppressing genes are located between the FI and H band of the same chromosome.

Animals↗
PubMed1989

The mouse bone marrow micronucleus assay can be used to distinguish aneugens from clastogens.

The occurrence of aneuploidy can be measured in several assays. However, none of them have been sufficiently validated. The bone marrow micronucleus test may be considered as a method for aneuploidy detection. In this work, micronuclei were induced by two aneugens, vincristine sulfate (0.1 mg/kg) and nocodazole (80 mg/kg), and two clastogens ethylmethanesulfonate (EMS) (300 mg/kg) and cyclophosphamide (60 mg/kg). Three criteria have been examined in order to distinguish micronuclei induced by aneugens and clastogens: the area of the micronuclei, the percentage of micronuclei with C-band-positive material and the DNA content of the micronuclei. C-band-positive micronuclei were found in 47% of the micronuclei for vincristine sulfate, 58% for nocodazole, 17% for EMS and 20% for cyclophosphamide. Areas of micronuclei showed a significant difference when induced by aneugens or by clastogens. Finally, the DNA content of micronuclei also showed a totally different distribution pattern when comparing the aneugen vincristine sulfate with the clastogen EMS. The three methods analysed could thus all make a difference between micronuclei induced by aneugens and those induced by clastogens.

Aneuploidy↗