| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
We have conducted an epidemiological study on the occurrence of chromosome anomalies in induced abortions, and obtained a few interesting findings concerning the etiology of chromosome anomalies. We confirmed the presence of maternal age dependence of chromosome anomalies even in the early pregnancy. Secondly, we observed that the ingestion of analgesics and antipyretics around the time of last menstrual period was statistically associated with the occurrence of trisomies in the Fl off-springs. The effects of the drugs are likely to be additive to the maternal age dependent occurrence of trisomies. In order to analyse the etiological role of drug ingestion on the induction of chromosome anomalies, we introduced an animal model by making use of mice.
The animals used were ICR female mice, aged 3-4 months and 11-12 months old. They were treated with PMS and HCG to induce ovulation. Aspirin or acetoaminophen was administered orally to the young females one hour prior to the HCG treatment.
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In the case of aged mice, only aspirin was administered. The doses of these drugs were 0(5% Arabic gum),250 and 500 mg/kg b.wt. Twelve hours after the administration, ova were collected from the oviduct and they were cytogenetically examined by using Tarkowski's method.
In the aspirin experiment by using young females, 30 and 26 females were used in the 250 and 500 mg groups,respectively. Of 910 and 862 ova collected,208 and 168 were successfully analyzed. In the case of acetoaminophen experiment, 18 and 20 mice were used in the 250 and 500 mg groups,respectively. Cytogenetic analysis was possible in 116 from 545 ova in the 250 mg group and 129 from 623 ova in the 500 mg group. As the control mice, 20 females were sacrificed and 148 out of 624 ova were chromosomally examined. Trisomic ovum was not observed in all groups. Incidence of hypoploids (e.g. monosomy) was about 10-15 %. But,it is likely to be an artefact at the time of slide preparation. In the experiment of aspirin administration in the aged mice, 18,16 and 12 females were used in the control, 250 and 500 mg groups, respectively.Cytogenetic analysis was made in 100 from 527 ova in the control group. In the test groups,98 from 416 and 65 from 341 ova were successfully analyzed. Numbers of trisomic ova were 2(2.0%),3(3.1%) and 1(0.7%) in the control,250 and 500 mg groups,respectivesy.
In the present study the administration of aspirin or acetoaminophen did not affect the occurrence of trisomies at the first meiotic division of mouse ovum. Neither additive nor synergistic effect of aspirin on the maternal age dependent occurrence of trisomies was disclosed. Less
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