The biochemical basis for genotyping 21-hydroxylase deficiency

Summary We describe three different forms of 21-hydroxylase deficiency—classical congenital adrenal hyperplasia (CAH), late-onset 21-hydroxylase deficiency, and cryptic 21-hydroxylase deficiency—and we present hormonal standards by which to assign the appropriate 21-hydroxylase deficiency genotype for these disorders. The late-onset and cryptic forms of 21-hydroxylase deficiency are biochemically indistinguishable, although patients with the late-onset disorder present with marked clinical symptoms (e.g. virilization) whereas patients with cryptic 21-hydroxylase deficiency are clinically asymptomatic. Our latest studies suggest that late-onset 21-hydroxylase deficiency, like the classical and cryptic 21-hydroxylase deficiencies, is also genetically linked to HLA, the major histocompatibility complex of man. Our biochemical findings provide evidence that a spectrum of 21-hydroxylase deficiencies exist in the population.This investigation was supported in part by USPHS, NIH Grants HD-00072 and HD-15084 from the NICHHD; CA-22507 from the NCI; and by a grant (RR47) from the General Clinical Research Centers Program of the Division of Research Resources     

Similar pigmentation characteristics in the specific-locus and the mammalian spot test. A way to distinguish between induced mutation and recombination

Animals with the same genetic constitution have similar pigmentation characteristics in both the specific-locus and the mammalian spot test. By microscopical analysis it is possible to distinguish between the following genotypes: a/a, p/p--light gray spots; a/a, d/d--gray spots; a/a, cch/c--light brown spots; a/a, b/b--brown spots; a/a, p cch/p cch--near-white spots; a/a, P C/P C--black spots. Near-white and black spots are presumed products of reciprocal recombination, especially if appearing simultaneously as a twin spot.     

Dose and effect of methyl-2-benzimidazolylcarbamate in the "mammalian spot test", an in vivo method for the detection of genetic alterations in somatic cells of mice.

In the spot test, mouse embryos which are heterozygous for four different recessive coat-colour genes are treated in utero by injection of a mutagen into the peritoneal cavity of the mother or by other appropriate routes of administration. If this treatment leads in a pigment precursor cell to an alteration of the wild type allele of one of the genes under study or to its loss, a colour spot in the adult coat may be seen. Peroral application of 100-300 mg methyl-2-benzimidazolylcarbamate (MBC)/kg to the mother during the tenth day postconception led to an increase in the frequency of colour spots in the coats of offspring. The data are consistent with the hypothesis that MBC is a point mutagen.     

Possible recombinogenic effect of caprolactam in the mammalian spot test

Tests of caprolactam in the mouse spot test showed that treatment with this compound increased the frequency of color spots among animals treated in utero. The nature of these spots suggests that caprolactam may induce spots through the induction of mitotic recombination.     

Effect of Habitat Patch Characteristics on Abundance and Diversity of Insects in an Agricultural Landscape

The objective of this study was to test for general effects of patch size, patch isolation, disturbance frequency, and patch life span, on density and diversity of organisms. We sampled predominantly herbivorous insects in 31 alfalfa fields that varied in size, isolation, frequency of disturbance by cutting, and age (number of years planted in alfalfa). Effects on insect relative density and diversity were examined at three taxonomic levels: all insects, eight separate orders, and six legume-specialist weevil species. We found that (a) more isolated alfalfa fields had higher overall insect richness, (b) fields with higher disturbance frequency had lower overall insect richness, and (c) fields of intermediate age had highest insect richness. In some cases these patterns were reflected at lower taxonomic levels, but in many cases they were not. These results are important because they indicate that, although we cannot simultaneously tailor a landscape for each of thousands of species, we may be able to produce desired effects at a more general level. Received 8 August 1997; accepted 2 January 1998.