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G Clayton

Publications and source records attributed to G Clayton.

9 recordsLinked to original sources
PubMed1992

The expression of GAP43 mRNA during the late embryonic and early postnatal development of the CNS of the rat: an in situ hybridization study.

GAP43 is a developmentally regulated phosphoprotein which is almost exclusively found in neurons. Numerous correlative studies have shown that GAP43 is expressed at high levels during neurite extension, axonal elongation and synaptogenesis. In this study we used in situ hybridization to examine GAP43 expression during late embryonic and early postnatal development. The highest relative levels of GAP43 at all stages were present in the neocortex. Levels in this and other regions peaked between postnatal days 5 and 10. These results indicate that high levels of GAP43 mRNA correlate most highly with the latter stages of axon outgrowth and with the early stages of synapse formation.

Animals↗
PubMed1986

The immunological detection of a 21-OH deficiency mutation HLA supratype.

Previous studies have shown that the late-onset and cryptic forms of 21-hydroxylase deficiency are highly associated with the HLA supratype HLA-B14,C4A2,C4B1/2,DR1. Since cells from a number of unrelated normal individuals from different ethnic backgrounds expressing the DR1 associated with this supratype failed to stimulate two different DR1-restricted T-cell clones that proliferated in the presence of most other DR1 cells, we decided to test the hypothesis that cells with this supratype express "abnormal" DR1 molecules that have been affected in some way by the chromosomal mutation responsible for B14,DR1-associated 21-hydroxylase deficiency (21-OH-defL). The results showed an association between "abnormal" DR1 and 21-OH-defL (elevated rates of 17 alpha-hydroxyprogesterone [17-OHP] increase and elevated peak 17-OHP values following ACTH stimulation). The presence of the B14,DR1 supratype can be used to predict the presence of "abnormal" DR1 and the clinical status of individuals not previously known to be 21-OH-defL carriers.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Pitfalls of prenatal diagnosis of 21-hydroxylase deficiency congenital adrenal hyperplasia.

Hormonal measurements and HLA genotyping of amniotic fluid at midgestation correctly predicted the postnatal diagnosis of congenital adrenal hyperplasia (CAH) in 29 of 32 fetuses at risk. Of these 29, 7 were predicted to have prenatal-onset classical 21-hydroxylase deficiency (21-OH def) based on elevated amniotic fluid 17-hydroxyprogesterone (17-OHP) and delta 4-androstenedione (delta 4-A) levels. These 7 fetuses and their index cases were ultimately proven to have salt-wasting classical 21-OH def. Of 5 who were HLA typed, the genotype was identical to the index case in 4; in one, HLA prediction was not possible, because the parents shared identical HLA antigens. Normal amniotic fluid 17-OHP and delta 4-A levels in the remaining 22 fetuses predicted that they were not affected with classical CAH. These children have been clinically asymptomatic to date or proven biochemically not to have classical or nonclassical CAH. Of the 22 fetuses, 11 were predicted by HLA genotyping to be homozygous normal or heterozygous for 21-OH def. In 3 of the 32 fetuses, prenatal diagnosis was incorrect. In one, the fetus was predicted to have CAH based on HLA identity to the index case. However, amniotic fluid 17-OHP and delta 4-A were normal, and the fetus was normal. The index case of this family did not have CAH, but was a normal child. Thus, amniotic fluid hormone levels accurately predicted a normal fetus, while HLA genotyping was not relevant in prenatal diagnosis because the index case was unaffected. The second fetus was predicted to be affected on the basis of HLA genotyping and to be unaffected based on normal amniotic fluid 17-OHP and delta 4-A. During infancy, this female infant had postnatal-onset nonclassical CAH. The index case in this family, presumed to have classical simple virilizing CAH, was later diagnosed to have nonclassical CAH. Thus, in nonclassical CAH, hormonal measurement of 17-OHP and delta 4-A is not useful in prenatal diagnosis; only HLA genotyping of the fetus is valuable. In the third case, the fetus was predicted to be a heterozygote by HLA genotyping and to be unaffected by hormonal measurement. Postnatally, at age 2 7/12 yr, the male child was found to have classical simple virilizing CAH and to be HLA-B-DR identical to his brother (index case) who also has classical simple virilizing CAH.(ABSTRACT TRUNCATED AT 400 WORDS)

17-alpha-Hydroxyprogesterone↗