Pediat. R e s . 10: 189-192 (1976 Extract after chickenpox infection. Two groups of normal children were studied as controls, one group before chickenpox infection and one Chromosomes were studied in 74-hr lymphocyte cultures from group during and I and 3 months after infection. ~h~ ages and seven patients with Down's syndrome and from 12 he ma to logic all^ sexes ofchildren included i n study are in ~~b l 1 and karyotypically normal control subjects. Six were studied be-and 2, fore and six after chickenpox infection. In Down's syndrome, the number of breaks per cell was 0. and also significantly greater than the number of breaks, 0.046 * trisomy 21 who ranged from 2--6 years of age and from six control 0.023, observed in control children with chickenpox. Therefore, children with normal karyotypes and normal hematologic findings, chromosomes from patients with Down's syndrome were signifi-2-6 years of age. Chickenpox was diagnosed clinically from the cantly more sensitive to breakage after chickenpox infection than appearance on the skin and mucous membranes of successive crops those from control subjects. of typical vesicles which was generally accompanied by a mild The incidence of chromosome breaks in Down's syndrome 1 constitutional reaction. Children with atypical chickenpox were month after chickenpox infection fell to the level observed in the excluded from this study. Blood samples were collected 1-3 days preinfection range. The present results showed that the difference after onset of the specific rash, and subsequently 1 and 3 months between the observed and the expected values for breakage in special after infection. N o individual had received either x-rays for regions of chromosome was not significant, but that chromosome diagnosis or chloramphenicol therapy in the recent past. breakage was random.) Chickenpox Down's s y n d r o m e c h r o m o s o m e d a m a g e

Introduction.It has been shown that X chromatin in nuclei derived from female infants is relatively less frequent during the first day of life while increases to adult frequency by about the fifth day.1~,2> Further, the evidence has been presented that Y chromatin in the newborn male nuclei is significantly lower in frequency at the first day of birth than in adults, but it increases to adult frequency during the neonatal period.3},4) Furthermore, we know that the lower frequency of X chromatin in neonates seems to occur in association with certain hormonal activities5~ : The frequency of X chromatin in nuclei of the cells of the parturient decreases within 24 hrs before and during 1-2 days after delivery. Some investigations were undertaken by us in order to inquire into the cause of the decrease in incidence of Y chromatin during the neonatal period in male infants, basing on the supposition that any relationship might be present between the lower incidence of Y chromatin during the neonatal period and the estrogen-level in newborn males, since an information is available indicating that the estrogenlevel in code blood is extremely high and then rapidly decreases after birth." with a hope to ascertain the relationship between the frequency of Y chromatin positive cells in adult males and the estrogenlevel, an examination was made with special regard to the transition of Y chromatin positive cells in adult males undergoing continuous medical treatments with estrogens after castration.Materials and methods. Blood smears were prepared from 22 adult males who have been receiving continuous therapy with estrogens after castration due to prostate cancer. Their mean age was 72.5±7.0 years and the term of therapeutic treatment ranged from three months to 12 years. Further, 22 normal adult males who had received no hormonal therapy during the near past provided blood samples for control. The mean age of the controls was 64.4±7.9 years.The subject of our observation deals with the occurrence and frequency of fluorescent bodies in lymphocytes derived from both