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Biomedical subjects

S LaFranchi

Publications and source records attributed to S LaFranchi.

30 records · Page 2Linked to original sources
PubMed1985

Effect of growth hormone replacement on development of hypothyroidism and hyperlipidemia.

To determine the frequency with which hypothyroidism develops during human growth hormone therapy and to corroborate its onset with blood lipid changes, we measured growth rate, serum T4 and T3, and plasma cholesterol, triglyceride, and lipoprotein concentrations at 4-month intervals for a year in two subgroups of hGH-deficient children. The first group was initially euthyroxinemic (n = 16), and the second was TSH deficient and therefore already receiving thyroxine (n = 15). Basal plasma concentrations of total and low-density lipoprotein cholesterol and, to a lesser extent, plasma triglycerides were increased in both groups compared with an age-matched reference group. Basal plasma cholesterol levels were not statistically different in the euthyroxinemic and thyroxine-treated subgroups, and hGH treatment for a year did not lower lipid values in either subgroup. With hGH replacement, 25% of the euthyroxinemic patients experienced a slowdown in growth rate (3.2 +/- 0.7 cm/yr) associated with decreasing T4 (4.8 +/- 1.1 micrograms/dl) and increasing cholesterol concentrations (218 +/- 23 mg/dl); with thyroxine treatment, the growth rate improved (6.9 +/- 2.2 cm/yr), T4 increased (10.0 +/- 4.0 micrograms/dl), and cholesterol decreased (173 +/- 44 mg/dl, P less than 0.05). Although our results do not justify routine thyroid replacement, they do indicate that hypothyroxinemia and hypercholesterolemia may precede the growth slowdown during hGH treatment, and the need to monitor thyroid function at this time.

Adolescent↗
PubMed1985

Comparison of growth hormone binding and metabolic response in rat adipocytes of epididymal, subcutaneous, and retroperitoneal origin.

We undertook a comparison of human growth hormone (hGH) binding and metabolic responses in rat adipocytes of epididymal, subcutaneous, and retroperitoneal origin to determine whether the site of fat depot biopsy might affect the response to hGH stimulation. The results showed highest specific binding in epididymal (3.6%), followed by subcutaneous (2.3%) and retroperitoneal adipocytes (1.5%); half-maximal binding was achieved at 14-18 ng/ml hGH for the three sites. Scatchard analysis of the binding data from each site was linear; there was no significant difference in binding affinities (2.1 to 3.3 X 10(9), M-1), but the number of binding sites was statistically higher in epididymal (9.8 X 10(3) as compared to subcutaneous (7.5 X 10(3), P less than 0.05) and retroperitoneal cells (3.3 X 10(3), P less than 0.01). Stimulation with 5 to 2500 ng pituitary hGH produced a dose-related increase in glucose incorporation, with the largest increase in epididymal fat cells (31%, P less than 0.05) followed by subcutaneous cells (18%, P less than 0.05); no significant increase was seen with retroperitoneal cells. Biosynthetic hGH produced a similar pattern of glucose incorporation in the three sites. Addition of hGH antibodies blocked the glucose incorporation in epididymal adipocytes using both pituitary-derived and biosynthetic hGH. It seems clear that this insulin-like effect is caused by hGH, not an insulin-like impurity. We conclude that the number of binding sites, perhaps related to adipose cell size, differs in adipose tissue from different locations and this influences the metabolic response to hGH stimulation.

Adipose Tissue↗
PubMed1984

Growth hormone assessment by radioreceptor and radioimmunoassay. Radioreceptor assay and radioimmunoassay comparisons.

To investigate possible human growth hormone (HGH) bioinactivity, serum radioreceptor assay (RRA) and radioimmunoassay (RIA) comparisons were made in 48 children undergoing an evaluation for growth retardation. Discrepancies between serum HGH concentrations by RRA and RIA were uncommon; the overall RRA/RIA ratio was 0.75. Significantly reduced HGH RRA/RIA ratios were seen at peak time periods following levodopa and arginine hydrochloride stimulation. Two subjects who demonstrated a discrepancy between serum HGH concentrations by RRA and RIA and somatomedin C levels in the hypopituitary range had malnutrition and chronic disease. There appeared to be an inverse correlation between nutrition, as assessed by a height age-weight age ratio, and RRA/RIA ratios in all subjects. While a reduced RRA/RIA ratio supports the diagnosis of bioinactive HGH, the administration of certain HGH secretagogues, malnutrition, and chronic disease may result in low HGH RRA/RIA ratios.

Arginine↗
PubMed1981

Amino acids as substrates in children with growth hormone deficiency and hypoglycemia.

In order to investigate the role of amino acid (AA) substrates in the hypoglycemia associated with human growth hormone (hGH) deficiency, we measured 12-hour fasting blood glucose and total quantitative AA concentrations in 11 children with hGH deficiency during three study periods: (1) before hGH replacement; (2) after 12 months of hGH treatment; and (3) after discontinuation of hGH for three months. The results were compared to studies in 16 control subjects. Fasting blood glucose concentrations were significantly (P less than .05) lower in the hGH-deficient children prior to hGH treatment as compared to the control subjects (67.0 +/- 5.3 vs 80.7 +/- 5.3 mg/100 ml, mean +/- SE). Fasting total serum AA concentrations were similar in the patients and in the control subjects; however, after 12 months of hGH replacement, there was a significant (P less than .01) elevation of serum AA (2,750 +/- 170 vs 2,283 micromoles/liter). Fasting serum concentrations of alanine, glycine, arginine, and tryptophan were also significantly elevated (P less than .01) with hGH treatment; ornithine, tyrosine, lysine, methionine, and phenylalanine showed lesser elevations (P less than 0.5), whereas threonine decreased significantly (P less than 0.01). The fasting hypoglycemia seen with isolated hGH deficiency is not an AA substrate-limited disorder. The finding of increased concentrations of AA with hGH replacement suggests increased retention of nitrogen and synthesis of AA for gluconeogenesis due to availability of other substrates.

Adolescent↗
PubMed1980

Plasma adrenocorticotrophic hormone in congenital adrenal hyperplasia. Importance in long-term management.

In a prospective study, assays of plasma adrenocorticotrophic hormone (ACTH) were compared with established criteria to evaluate the determination's usefulness in monitoring the control of congenital adrenal hyperplasia (CAH). In 22 infants and children with 21-hydroxylase deficiency, the plasma ACTH value correctly identified the status of control in 51 of 73 (70%) patient visits. Plasma ACTH concentrations were significantly higher in patients whose conditions were out of control when compared with patients whose conditions were under control, although there was an overlap between the two groups. Plasma ACTH concentrations were significantly higher in patients with sodium-losing CAH than in patients with non-sodium-losing CAH. These findings support the concepts that patients with the sodium-losing condition have a more severe enzyme deficiency and that ACTH stimulation may be affected by sodium balance. Although plasma ACTH determinations are a useful adjunct in the long-term management of CAH, they cannot be relied on as the sole criterion of control.

17-Ketosteroids↗
PubMed1979

Screening for congenital hypothyroidism: results of screening one million North American infants.

Pilot programs for screening of newborn infants for congenital hypothyroidism began in North America in 1972. To date, the five oldest programs (Quebec, Pittsburgh, Toronto, Oregon Regional, and New England Regional) have screened 1,046,362 infants. A total of 277 infants with congenital hypothyroidism have been detected and seven have been missed, resulting in a total of 284 affected infants in the screened population and an overall incidence of one in 3,684 live births. Of the affected infants, 246 were determined to have primary hypothyroidism, an incidence of one in 4,254 births. Ten infants with secondary-tertiary hypothyroidism were detected in Quebec, Oregon, and Toronto, an incidence of one in 68,200 births. Of all the infants with primary hypothyroidism who were adequately studied, 63% were determined to have aplastic or hypoplastic glands, 14% normal or enlarged glands, and 23% ectopic thyroid tissue. The estimated minimum incidence of infants with TBG deficiency is one in 8,913 births. Only 8 of the 277 detected infants were suspected clinically to have congenital hypothyroidism prior to the time of confirmation of the diagnosis at 4 to 8 weeks of age. The cost of screening varied from $0.70 to $1.60 per infant, depending on which costs were included in the estimate. Preliminary evidence from Quebec suggests that infants treated in the program have normal developmental testing scores at 18 months of age.

Alpha-Globulins↗
PubMedDate not supplied

Severe virilization in a girl with a steroid cell tumor of the ovary.

We report a 6-year-old girl with striking signs of virilization, as well as elevated concentrations of testosterone and 17-hydroxyprogesterone. Although the elevated 17-hydroxyprogesterone concentration initially suggested late-onset 21-hydroxylase deficiency, she was found to have an ovarian mass by sonography which at surgery proved to be a hilus cell subtype of steroid cell tumor. This intra-ovarian tumor appears to be the smallest tumor of its type ever reported. The testosterone concentration was normal three days after tumor resection and has remained so two years later.

17-alpha-Hydroxyprogesterone↗