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P Vercauteren

Publications and source records attributed to P Vercauteren.

6 recordsLinked to original sources
PubMed1988

SCE variability in lymphocytes and fibroblasts. A controlled study.

To determine whether the sister chromatid exchange (SCE) distributions obtained in lymphocytes and fibroblasts from different individuals are comparable, a controlled study was set up. Peripheral blood and skin biopsies were taken on the same day from five individuals living for years under the same environmental conditions. All samples were treated in the same fashion, and the SCEs were scored in 50 metaphases of peripheral blood lymphocytes and of skin fibroblasts in an early and in a late passage. A repeat blood sample was taken from the same five individuals 1 year later. Based on the results obtained in this first part of the study, five randomly chosen healthy blood donors were sampled at different times and studied in the same fashion. Each chromosome was identified, and the SCE scores were tabulated per chromosome over 50 metaphases. The statistical analysis consisted of fitting log linear models to these scores and examining the best fit by determining the exceedance probabilities (observed significance level). For lymphocytes, the results indicated that the SCE distributions depended only on the chromosome examined, and not on BrdU-exposure time, individuals, or time of sampling. Treatment with ethyl methane sulfonate (EMS) increased the number of SCEs proportionally on all chromosomes. Analysis of the SCE scores on lymphocytes and fibroblasts of the five individuals and on their low and high passage fibroblast cultures revealed the necessity of including higher order interactions in order to fit a suitable model to the data. Therefore comparison of the SCE scores of lymphocytes with those of fibroblasts or comparison of scores on fibroblasts from different individuals could not be done. In practice, to compare samples or individuals, it suffices to score the SCE on a limited number of chromosomes (e.G., the A group) of 50 metaphases.

Adult↗
PubMed1986

Non-uniform distribution of sister chromatid exchanges in human lymphocytes.

To test whether sister chromatid exchange (SCE) scores on human chromosomes have a uniform distribution, simulated SCE scores were generated and compared with observed scores using log-linear models. The analysis was performed at the level of the chromosome groups. Using this method we first tested whether the number of SCEs was distributed uniformly, i.e. proportional to the relative length of the chromosomes. Refinements of this hypothesis were made by considering a variable region around a first SCE to be inert for other SCEs and by making the occurrence of an SCE on a chromosome dependent on the occurrence of another SCE on the same chromosome. In further analyses it was tested whether the number of SCEs was proportional to the number of G bands on a chromosome, or to the DNA content of the chromosomes. None of the tested hypotheses fitted the observed data, establishing the non-uniform distribution of these events.

Adult↗
PubMed1984

Statistical evaluation of sister chromatid exchanges: refined method.

The statistical problems in evaluating the results of sister chromatid exchange (SCE) scores can be solved by fitting log-linear models to the number of SCE scores (2). In each single test all measurements from all chromosome groups, both from the control and from the experimental sets are utilized. Previously, we analyzed for each chromosome group the number of metaphases with specified total SCE score for the group. We have refined this method to an analysis of the total number of chromosomes with specified SCE score over all metaphases. The results show that the refined method uses more information and can lead to conclusions which are at variance with the conclusions of the first method. By proceeding in this way, better use is made of all available information on the SCE scores and the shortcomings of the classical Student's t-test and chi-square (X2) tests are avoided.

Cells, Cultured↗
PubMed1984

Statistical evaluation of sister chromatid exchanges.

Log-linear models are fitted to sister chromatid exchange (SCE) scores in order to test the significance of the differences in SCE scores observed between individuals or between experimental treatments. The analysis is performed at the level of chromosome groups. In each single test all measurements from all chromosome groups, both from the control and from the experimental sets, are utilized. By proceeding in this way full use is made of all the available information on the SCE scores at the level of chromosome groups and the shortcomings of the classical Student-t and chi-square tests are avoided.

Crossing Over, Genetic↗