Section 16 — Human Cytogenetics 



ma globulin in the whole population of cells as 

 well as production of individual cells will be 

 presented. 



16.44. Peroxidase Isozymes in Human Leucocytes. 



Barbara Z. Siegel and Kurt Hirschhorn 

 (New York, U.S.A.). 



Isozymes, altered but active forms of a 

 given enzyme, have been shown to exist in 

 human tissue and that their presence and in- 

 tensity may be both genetically and ontogeneti- 

 cally determined. A preliminary report on the 

 technique of preparation and identification of the 

 peroxidase isozymic series from human leuco- 

 cytes will be presented. Differences between cells 

 from normal and leukemic peripheral blood, 

 bone marrow and tissue cultures will be demon- 

 strated, as well as data on the qualitative and 

 quantitative variations. 



16.45. Influence of Steroid Hormones on Mammalian 

 Cells and Culture. David Stone (Shrewsbury, 

 U.S.A.). 



Studies on the influence of steroid hormones 

 on Hela cell cultures have indicated that it is 

 possible to select cell sub-lines which are in- 

 hibited in growth by particular steroids, but 

 not by others. Chromosome studies of these 

 cultures have indicated that the cell strain which 

 is inhibited in growth by both desoxycorticos- 

 terone and testosterone has a chromosome stem 

 line of 68, whereas the sub-lines resistant to 

 desoxycorticosterone or testosterone, respective- 

 ly, each have a stem line of 74 chromosomes. 

 In order to study the relationship of steroid 

 sensitivity and chromosomal characteristics 

 further, a cell strain having more classic diploid 

 characteristics] has been studied. Using cell strains 

 of the Chinese Hamster cultured for varying 

 periods in the presence of certain steroids, it has 

 been shown that the actions of the hormones 

 change with the length of culture over a period 

 of months. Cells which previously grew (at the 

 normal rate of growth) in a particular steroid 

 may become inhibited by the presence of that 

 steroid and later may be stimulated in growth 

 by the same steroid. Chromosome studies have 

 indicated that, compared to control cultures 

 run in parallel, the steroid supplemented cells 



exhibit altered numbers and morphologies of 

 their chromosomes. Even after one to two days 

 of steroid treatment small but significant changes 

 can be detected. The effects of steroid hormones 

 appear to be related to the age of the culture 

 and the particular batch of serum used in the 

 medium. These results will be discussed. 



16.46. Inherited Variation of Somatic Cells to Polio 

 Virus Infection. Lawrence N. Chessin (New 

 York, U.S.A.). 



Studies using primary human amnion cell 

 cultures have indicated that virus resistant 

 clonal variants can be selected from the parental 

 population. These variants are morphologically, 

 karyotypically, and immunologically indistin- 

 guishable from the sensitive population 



Studies on these resistant and sensitive clonal 

 types haves shown that cellular resistance and 

 susceptibility to poliovirus infection was clo- 

 nally distributed in a primary human amnion 

 population. Data from virus absorption, penetra- 

 tion and replication experiments will be dis- 

 cussed from the standpoint that somatic cell 

 variation to poliovirus infection may be due to 

 inherent differences in the mechanism for the 

 control of viral replication. 



16.47. An X-ring Chromosome in a Turner Patient 

 Without a Specific Peripheral Localization. 

 Th.W. J. HusTiNx(Nijmegen, the Netherlands). 



Chromosomal analyses in a Turner patient re- 

 vealed a ring chromosome in both blood- and 

 skin cultures. Barr-chromatine was detected in 

 part of the diploid skin nuclei. 



The ring chromosome is presumed to be a 

 mutated X chromosome. The X-ring seemed to 

 have preferentially a peripheral localization in 

 the metaphaseplates; in 42.5 per cent the ring 

 proved to be totally peripheral. The percentage 

 of metaphase-chromosomes, which are also pe- 

 ripherally localized was 41.1 per cent of all 

 karyograms had a peripheral localization in 

 the metaphaseplates in 45.3 per cent. 



The data for these different chromosome clas- 

 ses differed not significantly; the hypothesis of a 

 specific peripheral localization of the X-ring is 

 discarded. 





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