A comparison of the 8-hydroxydeoxyguanosine and micronucleus techniques for the assessment of X-ray and UV induced genotoxicity.

A comparison was made of the relative sensitivities of the cytokinesis-block micronucleus and the 8-hydroxydeoxyguanosine assays for the assessment of X-ray and UV-induced genotoxicity in mouse splenocytes in vitro. A detectable (p < 0.05) increase in micronuclei occurred at about 1/5 the X-ray exposure required to induce a significant increase in the level of 8-hydroxydeoxyguanosine. With UV radiation a significant (p < 0.05) rise in micronuclei was achieved at about 1/10th the dose needed to produce a detectable increase in 8-hydroxydeoxyguanosine levels. The data confirm the value of the cytokinesis-block micronucleus technique for the detection of genotoxicity at low-level X-irradiation, and indicate that it is more sensitive for that purpose than the 8-hydroxydeoxyguanosine assay. The data also demonstrate, for the first time, the production of 8-hydroxydeoxyguanosine by UVA/B-irradiation of intact cells, but point again to a more sensitive assessment of UV-related genotoxicity by the cytokinesis-block micronucleus method.

Reciprocal neurological developments of twins discordant for hydrocephalus.

Studies of 10 sets of twins discordant for hydrocephalus in early life revealed striking differences in degree and nature of development of verbal vs. non-verbal cognitive functions, birth order, and hand and eye preference. Despite similar (four dizygotic pairs) or identical (six monozygotic pairs) genetic endowment and grossly similar intra- and extra-uterine environmental and socio-economic influences, the consistency of the differences between the hydrocephalic children and their seemingly normal twins indicate systematic differences in pre-, peri- and/or early postnatal organization and development of hemispheric function. Follow-up studies also documented development of above-average intelligence, despite drastically reduced cerebral mantle size in hydrocephalus of early onset. The atypical patterns of development of the non-hydrocephalic twins also confirm previously described qualifications reported in studies of the significance of genetic vs. environmental factors in twins.

Transient neonatal Behcet's disease.

A term neonate with a transient form of Behcet's disease is described. The clinical and immunological features are detailed. As healing of the severe ulceration in this condition gives rise to scarring and cosmetic deformity recognition is important. Therapeutic intervention with corticosteroids is recommended after diagnosis.

Ventricular size and intelligence in achondroplasia.

Of 10 children with macrocephaly in association with achondroplasia only two children had progressive hydrocephalus. They were treated with a shunt procedure. One of these is intellectually and neurologically normal, and one is wheelchair bound and mentally retarded, with a spastic quadraplegia. Three children showed mild dilatation of the ventricles and one of these died from severe constriction at the foramen magnum. The other two are neurologically normal; one is intellectually normal but below average (WISC 88) and the other is slow normal at 18 months of age. Four children with demonstrated megalencephaly and a fifth with probable megalencephaly are all intellectually and neurologically normal. Intelligence in achondroplasia appears to be mainly in the normal range.

Children with large heads: a practical approach to diagnosis in 557 children, with special reference to 109 children with megalencephaly.

Among 557 children who presented a diagnostic problem of a large head, 109 had megalencephaly as the primary diagnosis. A clinical approach to the differentiation of this numerically important group from the various other causes of large head is outlined. The group is characterised by a familial incidence of large head in at least 50 per cent of cases; a male to female preponderance of four to one; an above-normal rate of head growth in 80 per cent of the children in the first four months after birth, and in a further 12 per cent in late infancy. The vast majority of these children were normal. Only seven children were retarded, and they also had a variety of neurological and other somatic abnormalities.