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Biomedical subjects

B Senior

Publications and source records attributed to B Senior.

18 recordsLinked to original sources

Effect of somatotropin of mammalian cell origin in growth hormone deficiency.

Sixty-nine growth hormone-deficient patients were treated for 1 year with somatotropin (recombinant DNA-derived human growth hormone) produced in mouse cells. The growth velocity of the 50 patients (72%) in whom the effectiveness of this growth hormone could be evaluated increased from a mean (+/- SD) of 3.5 +/- 1.1 to 8.7 +/- 1.6. cm/y. An enhanced rate of weight gain was also observed. Bone age was not unduly accelerated. One of 66 patients developed antibodies to recombinant growth hormone, which did not affect the response to therapy. No patient developed antibodies to host cell proteins. An increased insulin response to a standard glucose load, without any change in glucose tolerance, was observed after 1 year of treatment. This authentic sequence human growth hormone preparation produced in mammalian cells is both effective and safe in the treatment of children with growth hormone deficiency.

Adolescent

Adrenomyeloneuropathy presenting as Addison's disease in childhood.

Adrenoleukodystrophy, a sex-linked peroxisomal disorder that results in the impaired oxidation of long-chain saturated fatty acids and causes neurologic impairment, is a rare cause of Addison's disease in children. Adrenomyeloneuropathy is the name given to a biochemically identical but milder and more slowly progressive variant of adrenoleukodystrophy that affects young adults, in whom adrenal insufficiency may long precede nervous system dysfunction. The transmission of adrenomyeloneuropathy, like that of most cases of adrenoleukodystrophy, is sex-linked. Because of a preponderance of male patients among a group of patients with the onset of adrenal failure in childhood, we questioned whether this condition might be the initial manifestation of adrenomyeloneuropathy. We therefore measured the plasma concentrations of very-long-chain saturated fatty acids in eight patients with adrenal insufficiency; of these, five had elevated plasma hexacosanoic acid concentrations (range, 2.42 to 6.43 mumol per liter; mean normal level [+/- SD], 0.83 +/- 0.45), confirming the presence of adrenomyeloneuropathy. Magnetic resonance imaging showed clear evidence of brain involvement in all five patients. Reexploration of the family histories revealed additional missed cases. We conclude that the possibility of adrenomyeloneuropathy should be considered in any boy with Addison's disease.

Addison Disease

Hypoglycemia: a pathophysiologic approach.

An exploration of the factors that sustain glucose levels in the normal fasting subject reveals that the single major component is conservation of glucose rather than gluconeogenesis. Conservation is achieved by recycling of glucose carbon as lactate, pyruvate and alanine, and a profound decrease in the oxidation of glucose by the brain brought about by the provision and use of ketones. What glucose continues to be oxidized is for the most part formed from glycerol. Gluconeogenesis from protein plays little part in the process. Fasting hypoglycemia results from disorders affecting either one of the two critical sustaining factors--the recycling process or the availability and use of ketones. Individual hypoglycemic entities are examined against this background.

Blood Glucose

Remission in children with hyperthyroidism treated with propylthiouracil. Long-term results.

We treated 69 hyperthyroid children with propylthiouracil, of whom 53 remained under surveillance. Of these children, 34 (64%) had an initial remission, but relapses were frequent (47%). At this writing, 24 patients (45%) were in remission, with a mean duration of remission of 55 months (range, ten to 132 months). We found that the triiodothyronine level took significantly longer than the thyroxine (T4) level to return to normal. Thus, based on the T4 level alone, treatment may have been stopped prematurely in some patients, causing the relapse rate to be falsely high. The response to therapy did not depend on the size of the goiter nor on the initial levels of T4 or triiodothyronine. Six patients had adverse reactions, which were serious in two patients.

Adolescent

The secreted hemolysins of Proteus mirabilis, Proteus vulgaris, and Morganella morganii are genetically related to each other and to the alpha-hemolysin of Escherichia coli.

Secreted hemolysins were extremely common among clinical isolates of Proteus mirabilis, Proteus vulgaris, and Morganella morganii, and hemolytic activity was either cell associated or cell free. Southern hybridization of total DNA from hemolytic isolates to cloned regions of the Escherichia coli alpha-hemolysin (hly) determinant showed clear but incomplete homology between genes encoding production of hemolysins in the four species. One of the two E. coli secretion genes, hlyD, hybridized only with DNA from P. vulgaris and M. morganii, which produced cell-free hemolysis, but not with that from P. mirabilis, which showed only cell-associated activity. Molecular cloning of the genetic determinants of cell-free hemolytic activity from P. vulgaris and M. morganii chromosomal DNA allowed their functional analysis via inactivation with the transposons Tn1000 and Tn5. Both hemolysin determinants were about 7.5 kilobase pairs and comprised contiguous regions directing regulation, synthesis, and specific secretion out of the cell. Transposon mutations which eliminated secretion of the Proteus and Morganella hemolysins could be complemented specifically by the E. coli hemolysin secretion genes hlyB or hlyD. Alignment of the physically and functionally defined hly determinants from P. vulgaris and M. morganii with that of the E. coli alpha-hemolysin confirmed a close genetic relationship but also indicated extensive evolutionary divergence.

Bacterial Proteins

Hypercalcemia: an unusual complication of hyperthyroidism in a child.

Although well known in adults the association of hypercalcemia with hyperthyroidism has not been reported in children. We described how its occurrence in a hyperthyroid child obscured the manifestations of hyperthyroidism and discuss the factors that led to its appearance and regression.

Child

Value of computed tomographic scanning in patients with growth hormone deficiency.

In 18 of a series of 23 patients with growth hormone deficiency, computed tomographic scanning demonstrated a markedly small sellar volume. In four of the remaining five patients, the sella was enlarged. The cause of the enlargement was readily identifiable. Computed tomographic scanning of the sella appears to provide valuable supportive evidence of hypopituitarism.

Adolescent

Hypoglycemia in children.

The factors that sustain postabsorptive glucose concentrations have been analyzed and the adverse effects of various hypoglycemic disorders on these factors examined. The role of alanine has been reviewed and the importance of glycerol as a precursor of glucose and of ketones as a fuel substitute for glucose emphasized. Finally, we have suggested that fasting functional hypoglycemia replace ketotic hypoglycemia as a descriptive term and that we relinquish the concept of leucine-sensitive hypoglycemia as a specific entity.

Adult

The diagnosis of insulinoma in a child in the absence of fasting hyperinsulinemia.

This report concerns an 8-year-old girl with fasting hypoglycemia caused by a functional islet cell adenoma. During two separate fasting studies the blood glucose concentrations decreased to abnormally low levels yet the serum concentrations of insulin were consistently within the accepted range of normal. This report illustrates the diagnostic value of three simple functional tests--the inhibitory effect of insulin on ketogenesis and on glycogenolysis and the stimulatory effect of leucine on insulin secretion.

Adenoma, Islet Cell

Endocrine studies in a pubertal male pseudohermaphrodite with 17-ketosteroid reductase deficiency.

UNLABELLED: A 12 year old child (46,XY) with 17-ketosteroid reductase deficiency was investigated. The patient, reared as a female, was first noted to have clitoromegaly at 10 years of age. Increased facial hair, deepening of the voice, acne, increased body hair and minimal breast development were noted at 12 years. delta4-Androstenedione (delta4) in peripheral blood was markedly elevated (1913 ng/100 ml) whereas testosterone (T) was in the male range of Tanner III puberty (240 ng/100 ml). Thus, delta4/T in this patient was 9.4, compared to a normal ration of 0.15 to 0.25. T/DHT was normal (10.5). Oestrone (Oe1) level was slightly elevated (6 ng/100 ml, normal: 2.5-4.5 ng/100 ml). Oestradiol (Oe2) was normal (1.7 ng/100 ml, normal: 1.5-3 ng/100 ml. Oe1/Oe2 was slightly elevated (3.6, normal: 1-2). At laparotomy, testes were found and spermatic vein blood was obtained prior to castration. Androgen determinations of spermatic vein blood demonstrated extremely high delta4 levels (283 microgram/100 ml) and low levels of T (16 microgram/100 ml). delta4/T in spermatic vein was 17, higher than in the peripheral blood, suggesting intact peripheral conversion of delta4 to T. Incubation of testes slices with delta4 demonstrated severely impaired conversion to T. Conversion of Oe1 to Oe2 was impaired to a lesser degree. CONCLUSION: 17-ketosteroid reductase deficiency was documented in vivo by impaired conversion of precursor hormones resulting in higher than normal delta4T and Oe1/Oe2 ratios in blood. In vitro studies with testes slices confirmed the enzymatic defect.

17-Hydroxysteroid Dehydrogenases

Studies in type I glycogenosis: the paradoxical effect of ethanol on lactate.

Paradoxically, ethanol, which raises lactate in normal individuals, lowers the elevated levels of lactate in patients with Type I glycogenosis. We found that, although lactate levels fell, pyruvate proportionately declined even more, resulting in an increased L/P ratio which indicates that, as in the normal, the oxidation of ethanol had generated NADH. In type I glycogenosis, the increased level of pyruvate-lactate derives from glycogenolysis. We found that, despite continued glycogenolysis, ethanol had caused less pyruvate-lactate to form. The effect of an increased NADH/NAD+ ratio on the flow of carbon through the Embden-Meyerhof pathway could account for the finding, presumably by its effect on the oxidation-reduction couples with diversion of carbon toward formation of triglyceride rather than pyruvate-lactate.

Adolescent