PRINCIPAL INVESTIGATOR (S ): Lillian H. Lockhart 



EXPERIMENT TITLE/NUMBER : Cytogenetic Studies of Blood, M111 



PROGRAM/MISSION : Skylab 2, 3, 



CLASSIFICATION : Human 



DISCIPLINE(S) : Genetics, Hematology 



OBJECTIVES : To analyze the chromosome patterns of astronauts preflight and 

 postflight giving special attention to findings suggestive of exposure to 

 ionizing irradiation. 



PROTOCOL : Blood lymphocyte studies were performed 5 times preflight and 6 

 times postflight. A total of 77 specimens were cultured and processed. The 

 cultures were incubated for 60 to 70 hours and processed by treatment with 

 Colcemid for 2 hours. The cell suspension was then treated with a hypotonic 

 solution and fixed with methanol and acetic acid. Slides were prepared by 

 flame drying. After Wright's staining, approximately 125 cells were examined 

 from each culture for minor structural defects and rearrangements. Each cell 

 with numerical or structural defects was photographed and karyotyped to 

 determine the chromosomes involved in the aberrations. 



EQUIPMENT : Blood collection device. 



RESULTS : Cytogenetic analysis of lymphocytes for fragments, deletions, 

 dicentrics, rings, exchange figures, translocations, and inversions showed 

 minor structural defects within normal range but major rearrangements were 

 increased. It seems unrelated to flight as it also occurred in the ground 

 control. The etiology is unknown. 



CONCLUSIONS : It is impossible to speculate as to the effects of high altitude 

 flying and weightlessness on the chromosome structure of man. It would 

 appear, however, that the flights were not a significant factor in 

 contributing to the increase in minor chromosomal aberrations or the 

 appearance of chromosomal rearrangements. 



PUBLICATIONS : 352, 353 



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