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F J Dill

Publications and source records attributed to F J Dill.

25 records · Page 2Linked to original sources
PubMed1976

Nondisjunction in aging female mice.

Oocytes from CBA mice varying in age from 2 to 11 months were cultured to the metaphase II stage of meiosis and the chromosomes analyzed. The oocytes from three maternal age groups were compared with respect to the mean number of oocytes obtained per mouse, the frequency of maturation to metaphase II, and the frequency of numerical chromosomes abnormalities. Both the mean number of oocytes obtained per mouse and the frequency of maturation decreased markedly with maternal age. The frequency of chromosome abnormalities in the oocytes increased with maternal age from the young to the middle-aged mice but dropped off in the oldest maternal age group. No hyperploid (n + 1) oocytes were observed in the young or old group of mice, but 5.2% hyperploidy occurred in the middle-aged group. It is suggested that the lack of hyperploid oocytes in the old CBA females might be due to a threshold effect in which oocytes that are damaged by the number of univalents present at metaphase I become atretic and do not progress to metaphase II. The frequency of diploid (2n) oocytes was 1.7% and was not maternal-age dependent.

Aging↗
PubMedDate not supplied

Infantile autism: an occasional manifestation of fragile (X) mental retardation.

Classical infantile autism occurs more frequently in males and has recently been noted in patients with the fragile (X) form of X-linked mental retardation (XLMR). In order to better understand this association and to determine whether fra(X) XLMR could account for the excess of autistic males, we investigated a group of institutionalized severely handicapped adults, 33 males and eight females, who were diagnosed as autistic using the DSM III diagnostic criteria of infantile autism. Chromosome studies using FUdR showed that three of the males had the Xq27 fragile site. We confirmed the association of autism and fra(X) XLMR, and showed that this extreme form of behaviour is part of the spectrum seen in the Martin-Bell syndrome. Two of the three autistic males with the Xq27 fragile site had a history of birth insults, which in combination with developmental deficits due to the fragile X gene, might have led to the behavioural disorder. Even though the fragile X cannot account for the excess of males with classical autism, it is an important X-linked factor in its cause. The diagnosis can allow more accurate counselling for this subset of autistic males.

Adult↗
PubMedDate not supplied

Normal male carriers in the fra(X) form of X-linked mental retardation (Martin-Bell syndrome).

Evidence for the transmission of X-linked mental retardation through normal male carriers is reviewed in 6 kindreds. In these pedigrees we identified 15 unaffected males who likely had passed the gene on through their daughters. Fifty-one mentally retarded grandsons or great grandsons descended from these male carriers. In total, these males had 50 daughters with only 2 of them being of low intelligence. Two of the male carriers were recently identified through fra(X)- positive results in their mentally normal daughters. Among the sibs of these males, mentally retarded brothers were found in 3 families. This was unexpected since earlier observations suggested that the risk for mental retardation among sibs of nonmanifesting carriers is exceedingly low.

Female↗