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Biomedical subjects

S Pang

Publications and source records attributed to S Pang.

At least 127 records · Page 7Linked to original sources
PubMed1980

New studies of the 11 beta-hydroxylase and 18-hydroxylase enzymes in the hypertensive form of congenital adrenal hyperplasia.

Studies in four children with congenital adrenal hyperplasia due to 11 beta-hydroxylase deficiency provide evidence for two separate 11 beta-hydroxylating systems in the adrenal zona fasciculata and zona glomerulosa. In addition, these studies support the proposal that the adrenal 11 beta- and 18-hydroxylating activities are related and may involve the same enzyme protein and catalytic site. In the untreated or poorly treated state, despite elevation of deoxycorticosterone (DOC) and tetrahydrodeoxycorticosterone, urinary free 18-hydroxy-DOC was in the low normal range and did not increase normally with ACTH. PRA and urinary free 18-hydroxycorticosterone (18-OHB), tetrahydroaldosterone (TH Aldo), and pH 1 aldosterone were suppressed in the untreated and ACTH periods. Glucocorticoid administration suppressed plasma ACTH, and urinary tetrahydro-DOC and free DOC excretion decreased to the normal range. Concomitantly, there was a rise in PRA accompanied by parallel increase in urinary 18-OHB, urinary TH Aldo, and pH 1 aldosterone. While on dexamethasone, a low sodium diet (10 meq/day) resulted in prompt sodium retention, with a further rise in PRA and urinary 18-OHB, TH Aldo, and pH 1 aldosterone. These studies indicate the presence of both an 11 beta- and an 18-hydroxylase deficiency in the zona fasciculata and normal 11 beta- and 18-hydroxylase function in the zona glomerulosa, suggesting that these two enzymatic functions are related and that separate enzyme systems are present in the two zones.

Adolescent↗
PubMed1980

Cryptic 21-hydroxylase deficiency in families of patients with classical congenital adrenal hyperplasia.

Serum androgens and 17-hydroxyprogesterone concentrations and HLA genotypes were determined in 124 families of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH). In 8 pedigrees, we discovered 16 pubertal or postpubertal family members of either sex who had biochemical evidence of 21-hydroxylase deficiency but were without clinical symptoms of excess virilism, amenorrhea, or infertility. We designated these family members as individuals with cryptic 21-hydroxylase deficiency. Within each generation, the family members with cryptic 21-hydroxylase deficiency were HLA identical. It is proposed that these family members are genetic compounds, having 21-hydroxylase deficiency as a result of two recessive gene defects: 1) a severe 21-hydroxylase gene defect present in the index case with classical CAH (21-OHCAH) and 2) a mild 21-hydroxylase gene defect (21-OHCRYPTIC). Thus, the CAH genotype in the family members with cryptic 21-hydroxylase deficiency is 21-OHCAH/21-OHCRYPTIC. Lod score analysis for linkage between the cryptogenic 21-OH trait and HLA gave a combined Lod score for males and females of theta = 0.00 of 3.409. Close genetic linkage between HLA and 21-OHCRYPTIC was thus established. This study provides support for the previously reported heterogeneity of 21-hydroxylase deficiency which may result from allelic variability at the locus for steroid 21-hydroxylase.

17-alpha-Hydroxypregnenolone↗
PubMed1979

Prenatal diagnosis of congenital adrenal hyperplasia (21-hydroxylase deficiency) by HLA typing.

Congenital adrenal hyperplasia (C.A.H.) due to 21-hydroxylase deficiency is an HLA-linked recessive disorder. HLA-A and B antigens are expressed on amniotic cells. Prenatal diagnosis of C.A.H. by HLA typing of families and amniotic cells was attempted in two at-risk families. In one family HLA typing indicated that the fetus would have C.A.H., and this prediction was confirmed after birth. In the second family, HLA typing indicated that the fetus would be an unaffected, phenotypically normal carrier of the disease gene, and this prediction was also confirmed after birth.

Adrenocortical Hyperfunction↗
PubMed1979

Hormonal phenotype and HLA-genotype in families of patients with congenital adrenal hyperplasia (21-hydroxylase deficiency).

The response of 17-hydroxyprogesterone (17-OHP) and cortisol (F) to a 6-hr ACTH stimulation in families of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency was studied. These studies demonstrated that siblings who should be heterozygous carriers of the 21-hydroxylase deficiency gene based on HLA genotyping are hormonally different from the general population. In pre- and early pubertal children predicted to be heterozygous carriers of the gene based on HLA genotyping, the 17-OHP level (13.1 +/- 4.5 ng/ml), the rate of increase of 17-OHP (0.03 +/- 0.01), and the ratio of 17-OHP/F at 6 hr (0.27 +/- 0.07) were significantly higher (P less than 0.001) than in the control population, (3.9 +/- 1.9, 0.009 +/- 0.005, and 0.08 +/- 0.04 ng/ml, respectively). In late and postpubertal males, these hormonal parameters in the heterozygotes (17 +/- 9.7, 0.04 +/- 0.026, 0.42 +/- 0.33 ng/ml, respectively) were significantly higher (P less than 0.001) than in the general population (5.3 +/- 1.6, 0.009 +/- 0.004, and 0.1 +/- 0.03 ng/ml, respectively). In postmenarchal females, the mean hormone responses in the heterozygotes (12.1 +/- 9.7, 0.03 +/- 0.02, and 0.27 +/- 0.24 ng/ml, respectively) were significantly higher (P less than 0.005, less than 0.01, less than 0.005, respectively) than in the general population (5.2 +/- 2.5, 0.01 +/- 0.007, and 0.1 +/- 0.04 ng/ml, respectively). However, the overlapping values did not permit a clear differentiation of the hormonal responses in these two groups. Another (ACTH) stimulation in one family demonstrated that a father of a patient probably is a previously unrecognized homozygous affected patient and,thus, revision of the congenital adrenal hyperplasia (CAH) genotype for this family was required.

Adrenal Hyperplasia, Congenital↗
PubMedDate not supplied

Empty sella syndrome in childhood.

The empty sella syndrome is common in middle-aged women, usually presenting with headache, and only occasionally associated with endocrine or visual abnormalities. It is rare in childhood. Childhood cases tend to present either with endocrine disturbances, visual symptoms, or with craniofacial syndromes. We present three cases of complete empty sella with childhood onset, each discovered unexpectedly during evaluation of endocrine or visual dysfunction.

Adolescent↗
PubMedDate not supplied

Insulin stimulates the release of a subset of GPI-anchored proteins in a G-protein independent manner.

The glycosyl-phosphatidylinositol anchored protein, membrane dipeptidase (EC 3.4.13.19) is released from the surface of 3T3-L1 adipocytes in response to insulin treatment through the action of a phospholipase C. The present study investigates the role of guanine-nucleotide binding proteins (G-proteins) in this process. Treatment of permeabilized 3T3-L1 adipocytes with GTPgammaS did not cause release of membrane dipeptidase into the medium, while GDPbetaS did not inhibit the insulin-stimulated release of membrane dipeptidase. Other activators of G-proteins, including the tetradecapeptide mastoparan, pertussis toxin and AlF3, also caused no significant release of membrane dipeptidase from the surface of the 3T3-L1 adipocytes. From these observations it is concluded that G-proteins are not involved in the insulin-stimulated release of membrane dipeptidase. Although X-Pro aminopeptidase (EC 3.4.11.9) is GPI-anchored in 3T3-L1 adipocytes as shown by digestion with bacterial phosphatidylinositol-specific phospholipase C, it was not released upon insulin treatment of the cells, indicating that only a subset of the GPI-anchored proteins are susceptible to insulin-stimulated release.

3T3 Cells↗
PubMedDate not supplied

Prenatal diagnosis and treatment of congenital adrenal hyperplasia.

Advances in technology have made possible the prenatal diagnosis and treatment of female fetuses with classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Hormonal measurement of 17-hydroxyprogesterone, androstenedione, testosterone and 21-deoxycortisol and HLA typing and DNA analysis for 21-OH/C4/HLA class I and II genes in chorionic villus cells and amniocytes are utilized for prenatal diagnosis. Maternal dexamethasone administration begun in the first trimester has prevented or ameliorated virilization in approximately three-fourths of infants. Maternal estriol levels appear to be the most accurate measure of fetal adrenal suppression. Maternal side effects are not infrequent and include excess weight gain, edema, glucose intolerance, hypertension and gastrointestinal problems. Severe permanent striae have been reported. Although no complications of prenatal treatment in the treated fetus or child have been reported long-term follow-up with careful neuropsychologic evaluation is not yet available and is necessary to fully evaluate possible long-term side-effects of prenatal dexamethasone treatment.

Adrenal Hyperplasia, Congenital↗