Chromosome abnormalities in bone marrow of Thorotrast administered patients

The chromosomally abnormal clones occurring with high frequencies in bone marrow of 3 Thorotrast administered patients were studied by annual follow up observations. In one case the frequency of the clone was maintained fairly constant, but in another case it showed a tendency of increase, and in still another case the frequency of the clone showed drastic changes from year to year. The karyotypes of the clones showed remarkable chromosome abnormalities, among which the large partial loss of chromosomes was especially noted in all the 3 cases. (author)