Biomedical subjects
Publications and source records attributed to K Bajnóczky.
The possible effect of in vivo oxygen exposure on chromosomes was examined in lymphocyte cultures of 12 very-low-birthweight infants on the 1st, 8th, and 16th days of intensive care. No increase of cytogenetic anomalies was seen in untreated and bleomycin-treated cultures. The findings suggest that neonatal oxygen exposure is unlikely to cause latent chromosome damage.
Chromosomal instability was examined in 20 apparently healthy children of survivors of childhood malignancy. As compared to controls, no increase of spontaneous or bleomycin-induced aberrations (including gaps, breaks, sister chromatid exchanges, pulverization, and premature centromere divisions) were found in these "index children." The results suggest that the offspring of subjects previously receiving chemotherapy and/or radiotherapy for childhood malignancy are probably at no increased risk of latent chromosomal instability.
Anthropometric, dysmorphologic, and cytogenetic investigations of 21 children of 20 survivors of childhood malignancy revealed no signs of congenital anomalies in any of the subjects examined. No increase of mild errors of morphogenesis (minor anomalies) was observed in the well-developing children; no latent chromosome instability was found in their Bleomycin-treated lymphocyte cultures either. The suggestion that previous oncological therapy does not lead to an increased risk of congenital disorders in the offspring was confirmed by the present findings obtained with various, in part new methods.
Chorionic villus sampling was performed for chromosome analysis in 387 cases during a 4-year-period. In 115 cases transcervical while in 272 cases transabdominal sampling was carried out. Chromosomal abnormalities were found in 25 cases (6.4%). Autosomal trisomies occurred in 17 cases, structural anomalies in 2 cases and sex chromosomal aberrations in 6 cases. The pregnancy was terminated in 19 cases because of chromosome abnormality, in 5 further cases because of X-linked disease and male fetus. After transcervical sampling spontaneous abortion occurred in 7 cases (5.8%), while after transabdominal sampling in 8 cases (2.8%). The authors prefer in their practice the early transabdominal CVS, which can be performed safety already at the end of the first trimester.
An increased frequency of mitoses with centromere separation affecting all chromosomes was found in lymphocyte cultures from a couple with recurrent spontaneous abortions. The phenomenon was observed in both the wife and husband. The abnormal behaviour of centromeres may predispose the individual to cell division errors, the consequence of which may be a spontaneous abortion.
A total of 224 cases of spontaneous abortions were studied by analysing chromosomes directly from chorionic villi. Abnormal karyotypes were found in 51.3% of the investigated cases. Among the chromosome abnormalities the most frequent were the trisomies (55.7%), followed by polyploidy (23.5%), monosomy X (15.6%) and structural anomalies (5.2%). The rapid and relatively simple method is suitable for studying the causes of spontaneous abortions, and this information may be helpful also for genetic counselling.
Two hundred cases of spontaneous abortions were studied by analysing chromosomes directly from chorionic villi. Abnormal karyotypes were found in 52% of the investigated cases. Among the chromosome abnormalities the most frequent were the trisomies (56.7%) followed by polyploidy (23.1%), monosomy X (15.4%) and structural anomalies (4.8%). The rapid and relatively simple method is suitable for studying the causes of spontaneous abortions, and these information may be helpful also for genetic counselling.
Analysis of the results of 3411 routine cytogenetic examinations initiated by abnormal phenotype or family history revealed that out of 44 cases with balanced structural aberration 12 patients had an abnormal phenotype. Of the 12 cases, there were four reciprocal translocations, three Robertsonian translocations, and five pericentric inversions. Eight rearrangements were inherited, one had occurred de novo, and three were of unknown origin. Each carrier parent was apparently healthy. In all of the four cases with reciprocal translocation the rearrangements were of paternal origin. None of the clinical abnormalities could be assigned specifically to the breakpoints. Explaining the association of balanced chromosomal rearrangement and clinical abnormalities, possibilities of causal relationship and by chance coincidence are discussed.
Authors report on a Down infant, whose chromosome complement includes an extra small bisatellited marker chromosome. This marker was also found in four healthy members of the family.
The centromere separation sequence was determined in the mitoses of 5 subjects with "balanced" D/D translocations. Similarly to the acrocentrics, also the D/D fusions belonged to the chromosomes the sister chromatids of which separated last in the late metaphase stage.
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A rapid method of chromosomal analysis of the newbornbabies is described. The karyotype of the newborn can be detected with the use of direct preparation from the cord blood within a few hours. This can be helpful in the cases of suspected chromosomal aberration, and in that of ambigous genitalia to decide the further activities or to choose the right legal sex.
The sequence of centromere separation in human chorionic cells was analyzed in two laboratories. Despite of certain interexaminer variations, in both series chromosomes 18, 2, 12, 4, 5, 17 and X proved to be early dividing and the acrocentrics were the last to separate. The pattern was very similar to those observed in other human tissues, which reflects a species-specific sequence of centromere separation.
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We have studied the centromere separation sequence in lymphocyte mitoses of the parents of four infants with trisomy 18, five patients with trisomy 21, and five children with normal karyotype. "Late separation" of chromosome 18 was found in both parents of a neonate with trisomy 18, "early separation" of chromosome 21 in three mothers and in one father of four children with trisomy 21. No "out-of-phase" separation occurred in the mitoses of the parents of normal children. The findings provide further evidence for the correlation between alteration of the parental centromere separation sequence and aneuploidy of the offspring.
An abnormal and highly variable centromere separation sequence was found in bone marrow mitoses of 20 patients with chronic myelocytic leukemia (CML). The most conspicuous alterations were the less frequent early separation of chromosome #3 in Ph-negative cases and the relatively late division of the X chromosome in the leukemic patients. The findings did not confirm an out-of-phase centromere division of chromosome #22 in CML.
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The centromere separation sequence of 5 old women (mean age 80.4 years), and 5 old men (mean age 75.5 years) was determined. Five young females (mean age 26.0 years) and 5 young males (mean age 27.4 years) served as controls. In each case 50 randomly selected lymphocyte mitoses were analysed microscopically and from photographs. In the groups of the young controls and aged men, the centromere separation sequence was clearly non-random and corresponded to the "normal sequence" observed in several earlier studies. In aged women chromosomes X, 8 and 10 divided earlier, while chromosomes 2, 3, 5 and 18 somewhat later than usual, but the individual and averaged patterns did not conspicuously differ from the "normal sequence". The premature centromere division (PCD) of X was not correlated with X-aneuploidy, and seemed not to correspond to the "long acentric fragment" often described in old females.