[Effects of Methotrexat on the chromosomes of a human fetus in vivo (author's transl)]. / Wirkung von Methotrexat auf die Chromosomen eines menschlichen Foetus in vivo

A pregnant woman in the 17th week of gestation with Hodgkin's disease was treated with 50 mg Methotrexate i.v. on the 3 days preceeding therapeutic abortion. Cytogenetic studies on blood, brain, skin and lung of the fetus were performed. Slight structural aberrations such as gaps, chromatid breaks and accentric fragments were found in an average of 8,5% of the counted metaphases. The following drastic structural chromosome aberrations were found in 24,8% of all observed metaphases: 1) mitoses with stretched chromosomes, comparable with special segments (9,9%). 2) clumping of chromosomes in varying degrees (5,4%). 3) combinations of 1) and 2) (0,4%). 4) nuclear fragments (7,4%). 5) pulverized chromosomes (1,7%). Endoreduplications were found in 2%. The modal number was 46 with a rate of 50,1%, hypodiploids 46,3%, hyperdiploids and polyploids 3,6%. Karyotype: 46, XX.

[Effect of ultraviolet light on human chromosomes (author's transl)]. / Uber die Wirkung von ultraviolettem Licht auf menschliche Chromosomen

Lymphocytes were cultured in quartz flasks and irradiated by UV light. Time of exposure and moment of application varied. After UV treatment, pulverization of the chromosomes occurred and larger nuclear fragments which might be products of an abnormally proceeding mitosis with chromatin confluence were observed. The usual chromosome aberrations such as breaks, special segments, abnormal chromosomes and polyploidy have been rarely observed, but are found more often in those cultures where pulverization and nuclear fragments are less abundant. A number of mitoses in the irradiated cultures, however, shows no chromosomal aberrations. The ratio of unaffected to unaffected mitoses is dose-dependent. Chromosome fragmentation can result from UV irradiation occurring at any instance during the time of culture. One finds maximum and minimum amounts of damage when a constant dose is applied at various times.