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Biomedical subjects

B Senior

Publications and source records attributed to B Senior.

At least 19 recordsLinked to original sources
PubMed1992

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↗
PubMed1990

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↗
PubMed1989

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↗
PubMed1987

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↗
PubMed1987

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↗
PubMed1986

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↗
PubMed1986

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↗
PubMed1985

Contrast sensitivity in diabetics with and without background retinopathy.

Contrast sensitivity measurements were obtained from 64 patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus who had normal Snellen acuity and minimal or no visible diabetic retinopathy. Contrast thresholds were determined for stationary gratings at six spatial frequencies, ranging from 0.5 to 22.8 cycles/degree (c/deg), and for 1.0-c/deg gratings phase-alternated at 15 Hz. Data from each group of diabetic patients were compared with data from age-matched normal subjects. We found that (1) patients with IDDM and no retinopathy had normal contrast sensitivity, (2) patients with NIDDM and no retinopathy had abnormal contrast sensitivity at only one spatial frequency (22.8 c/deg), and (3) patients with NIDDM and background retinopathy had abnormal contrast sensitivity at all spatial frequencies tested. We also found a dissociation of Snellen acuity and contrast sensitivity, indicating that contrast sensitivity can be used as an early index of changes in the retina not demonstrated by measurements of visual acuity.

Adolescent↗
PubMed1984

Ketonuria does not exclude hyperinsulinemic hypoglycemia.

We examined the relationship between serum beta-hydroxybutyrate (BOHB) and plasma glucose concentrations and between serum free fatty acid (FFA) and glucose concentrations in 34 normal children who fasted for up to 24 hours. The BOHB concentration correlated inversely with the glucose concentration, as did the FFA concentration. We compared these results with those in six patients with hypoglycemia due to hyperinsulinism. In the hyperinsulinemic children, hypoglycemia was invariably associated with relative hypoketonemia (glucose concentration, less than 40 mg/dL; BOHB concentration, less than 2mM; greater than 2 SDs below the mean). The FFA concentrations were also unduly low (greater than 2 SDs). However, despite being significantly hypoketonemic when hypoglycemic, four of the six hyperinsulinemic patients had ketonuria. Since it does not exclude hyperinsulinism, ketonuria may be a potentially misleading finding in a hypoglycemic child.

3-Hydroxybutyric Acid↗
PubMed1983

Hypoketonemia and age-related fasting hypoglycemia in growth hormone deficiency.

Body fuels were measured in 45 normal children and 17 growth hormone-deficient patients after 24 hours of fasting. After three months of therapy with human Growth Hormone (hGH) 16 of the patients were restudied. In all groups, beta-hydroxybutyrate (BOHB) concentrations correlated inversely with age and with glucose concentrations. When adjusted for these factors, the concentrations of BOHB were significantly lower in the growth hormone-deficient patients than in the control children, before (P less than 0.01) as well as after therapy (P less than 0.01). Only the five youngest patients became hypoglycemic. During fasting, ketones, which serve as an alternative fuel for the brain, spare glucose. Thus, a shortage of ketones would compromise the ability of the patient to conserve glucose and predispose the patient to fasting hypoglycemia. Accordingly, we propose that hypoketonemia is a critical factor in the genesis of fasting hypoglycemia in growth hormone deficiency.

Adolescent↗
PubMed1982

Fat-derived fuels during a 24-hour fast in children.

We examined the availability of fat-derived fuels in 23 normal children aged 1.9 to 16.7 years who fasted for 24 h. We found a rapid and progressive rise in the blood concentrations of free fatty acids (FFA) and ketones. There was a highly significant negative correlation between the concentrations of beta-hydroxybutyrate (beta OHB) and glucose and also between beta OHB and age. With time, the ratio of beta OHB to acetoacetate (AcAc) progressively increased. We briefly review the vital role of ketones in the adaptation to fasting and point out that qualitative tests of ketones can be misleading. Our results indicate that quantitative determinations are essential in the evaluation of suspected disorders of fuel metabolism and that the results must be interpreted according to the age of the child, the duration of fasting, and the concomitant concentrations of glucose.

Acetoacetates↗
PubMed1982

Hypoalaninemia and ketotic hypoglycemia: cause or consequence?

A shortage of alanine for gluconeogenesis is believed responsible for various forms of hypoglycemia and in particular ketotic hypoglycemia (KH). We examined the glucose-alanine relationship in two groups of fasting children, 18 with KH and 44 controls. Glucose levels declined in both groups but significantly more in KH; to 1.98 +/- 0.20 versus 3.26 +/-0.13 mM (mean +/- SEM; P less than 0.001). Alanine also fell in both groups, the concentrations correlating significantly with the concomitant glucose levels (KH: r = 0.64, P less than 0.001, and controls: r = 0.50, P less than 0.001). The relationship of alanine to glucose gave virtually identical regression equations, y = 0.054x + 0.063 for KH and y = 0.054x + 0.050 for controls. The differences in alanine levels between the two groups were too small to account for the greater decline in glucose in KH. The results indicate that hypoalaninemia rather than causing hypoglycemia results from it.

Acidosis↗
PubMed1980

Failure to thrive and metabolic alkalosis. Adverse effects of a chloride-deficient formula in two infants.

This report concerns two infants with failure to thrive and hypochloremic metabolic alkalosis. Both infants were fed exclusively with a soybean-based formula, which, as a result of a manufacturing error, was severely deficient in chloride. When an alternative formula containing an adequate amount of chloride was prescribed, the electrolyte abnormality was corrected, and the infants resumed their normal weight gain.

Alkalosis↗
PubMed1980

Hypoparathyroidism and pregnancy. Treatment with calcitriol.

Calcitriol was used successfully to treat a patient with hypoparathyroidism during pregnancy. Increasing dosage of calcitriol were needed during the last trimester with a prompt decrease in the requirement after delivery. The dosage changes appear to mirror the pattern of endogenous synthesis of calcitriol in normal pregnant women.

Adult↗