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Biomedical subjects

J W Gregory

Publications and source records attributed to J W Gregory.

At least 55 records · Page 3Linked to original sources
PubMed1996

A new point mutation in the luteinising hormone receptor gene in familial and sporadic male limited precocious puberty: genotype does not always correlate with phenotype.

Genomic DNA from two families with male limited precocious puberty was examined for mutations of the LH receptor gene. In family 1, several members of the pedigree have FMPP, whereas in family 2 there is only one affected subject. A point mutation (T --> C at nucleotide 1192) resulting in substitution of threonine for methionine 398 in the second transmembrane domain of the LH receptor protein was found in both families. In addition, one member of family 1 has the mutation, but no evidence of precocious puberty. All obligate carriers within this family were shown to have the mutation, and it was not detected in 94 chromosomes from unaffected and unrelated white subjects. In family 2, the index case was the only one to have the mutation. A previously unreported neutral dimorphism (C --> T at nucleotide 1065) is also described.

Base Sequence↗
PubMed1993

Metabolic effects of growth hormone treatment: an early predictor of growth response?

Fourteen children receiving one year of recombinant human growth hormone (rhGH) treatment underwent measurement of serial changes in body composition (measured by skinfold thickness, bioelectrical impedance, and H2(18)O dilution), resting energy expenditure (REE, estimated by ventilated hood indirect calorimetry), and total free living daily energy expenditure (TEE, measured by the doubly labelled water technique). Mean height velocity increased from 4.9 to 8.6 cm/year after six months of treatment. Fat free mass (FFM) increased more during the first six weeks (24.4 g/day) than from six to 26 weeks of treatment (6.8 g/day); fat mass decreased by 7.2 g/day and 1.1 g/day respectively. The six week increase in REE (kJ/day) was maintained after six months of treatment, though expressed per kilogram FFM (kJ/kgFFM/day), returned to pretreatment values by three months. Height velocity increases at six months correlated with six week changes in fat mass measured by skinfold thickness and REE, though use of this relationship to predict growth response in individuals is limited by the wide 95% prediction intervals. No significant changes in growth, body composition, or energy expenditure were observed between six and 12 months of treatment, in either patients who had initially responded well to treatment or those who were poor initial responders to treatment and who had their dose of rhGH doubled after six months.

Adolescent↗
PubMed1993

Deficiency of 17-ketoreductase presenting before puberty.

The diagnosis of 17-ketoreductase deficiency is established in most patients at or after puberty when basal plasma androstenedione levels are high; data on prepubertal children are limited. Two infants with external female genitalia presented in infancy with inguinal herniae and palpable gonads. Both had a 46,XY karyotype, a short vagina, absent uterus, and a gonadal biopsy showing testicular tissue. The value of an hCG stimulation test in making the diagnosis of 17-ketoreductase deficiency was confirmed by a minimal plasma testosterone but marked androstenedione response. Androgen receptor deficiency based on studies in genital skin fibroblasts was demonstrated in one of the cases. We speculate that this is possibly the result of failed induction of receptors secondary to androgen deficiency. Though 'tomboyish' in behaviour, both children are reared as girls.

17-Hydroxysteroid Dehydrogenases↗
PubMed1992

Effects of oral testosterone undecanoate on growth, body composition, strength and energy expenditure of adolescent boys.

OBJECTIVE: We determined the effect of 3 months of daily, 40 mg oral testosterone undecanoate on growth, body composition, hand grip and quadriceps muscle strength, and total free-living daily energy expenditure in boys with constitutionally delayed puberty. DESIGN: Double blind, placebo controlled study. PATIENTS: Eighteen boys with constitutionally delayed puberty, mean (SD) age 13.2 (1.6) years. MEASUREMENTS: Body composition measurements were made by skinfold thickness, bioelectrical impedance and stable isotope dilution (H2(18)O) methods. Energy expenditure was assessed by the doubly-labelled water (2H2(18)O) technique. RESULTS: Height velocity increased from 5.4 (0.8) to 8.1 (0.6) cm/year (P < 0.05) in the 3 months after active therapy. Fat-free mass increased more with therapy (2.7 (0.3) kg) over the 6-month study period than with placebo (1.7 (0.4) kg, P < 0.5). Height velocity increases correlated with daily increases in fat-free mass (r = 0.68, P = 0.005) in the study group as a whole. Energy expenditure and muscle strength increased similarly in both groups. Predicted adult height decreased in the group which was treated with testosterone undecanoate. CONCLUSIONS: Testosterone undecanoate (40 mg daily for 3 months) significantly increased height velocity and fat-free mass velocities after 6 months but not muscle strength, endurance or total daily energy expenditure.

Administration, Oral↗
PubMed1992

Body fat and overweight among children and adolescents with diabetes mellitus.

Body composition was assessed in 68 children and adolescents with diabetes mellitus. Body fat was measured by skinfold thickness and the results were compared with those obtained by bioelectrical impedance methods (r = 0.76, p less than 0.001). Percentage body fat from skinfold thickness estimations was 12-38%. Girls appeared to be most at risk of obesity during puberty with mean body fat 31%, significantly greater than in prepubertal girls (22%, p = 0.001) and pubertal boys (21%, p less than 0.001). Body fat increased progressively through puberty in girls, with those in late puberty (stages 4 and 5) having significantly more percentage body fat than those in earlier puberty (stages 2 and 3, p less than 0.001). Those in late puberty also received significantly more insulin per kilogram body weight (p = 0.05) and had higher HbA1 levels (p less than 0.05) than prepubertal girls.

Adipose Tissue↗
PubMed1992

Paediatric cardiac transplantation with steroid-sparing maintenance immunosuppression.

In order to determine the results of steroid-sparing maintenance immunosuppression in paediatric patients who have undergone orthotopic heart transplantation (OHT), a retrospective study was undertaken in 12 children and five infants (median age 3.5 years). Preoperative diagnoses were cardiomyopathy in seven and congenital heart disease in 10 patients. Immunosuppression was induced by cyclosporin, azathioprine, methylprednisolone, and antihuman lymphocyte immune globulin. It was maintained with cyclosporin and azathioprine. After induction, five patients received no further steroids. The remainder, except one, required only pulses for rejection (13 episodes or 0.51 episodes/patient year). Long term complications included hypertension in six, and renal impairment in three children. There were no early or late deaths from infection. Actuarial survival was 94% at one year. Of the children followed up for more than one year, all demonstrated an increase in height SD scores (mean (SD) -2.15 (1.35) to -1.15 (1.16)). We conclude that a steroid-sparing maintenance immunosuppression regimen can be successfully employed in paediatric OHT, and that significant catch-up growth can be achieved postoperatively.

Azathioprine↗
PubMed1991

Body water measurement in growth disorders: a comparison of bioelectrical impedance and skinfold thickness techniques with isotope dilution.

Total body water was estimated as part of the assessment of body composition in children with growth disorders, using the newly commercially available method of bioelectrical impedance. This was undertaken to compare the precision and accuracy of the results with those derived from skinfold thickness against measurement of stable isotopically labelled water (H2(18)O) dilution as a standard. The comparisons were carried out to see to what extent the impedance method could be applied with confidence to assessment of children with growth disorders. Total body water was derived from impedance (I) using an association with height (Ht2/I). Impedance and skinfold thickness estimates of total body water were equally precise when compared with values obtained from H2(18)O dilution (limits of agreement -1.9 to +1.3 and -1.7 to +2.0 kg respectively). The mean intraobserver coefficient of variation for repeat measurements of impedance was 0.9% compared with 4.6% for skinfold thickness with an interobserver coefficient of variation for impedance of 2.8%. Bioelectrical impedance estimation of body composition is likely to be of value in the growth clinic when expertise in measurement of skinfold thickness is limited or repeated measurements are to be undertaken by different observers.

Body Composition↗
PubMed1991

Changes in body composition and energy expenditure after six weeks' growth hormone treatment.

Changes in body composition and energy expenditure were assessed in 15 children after six weeks of human growth hormone (hGH) treatment. Body composition measurements were made by stable isotope labelled water (H2(18)O) dilution, bioelectrical impedance, and skinfold thickness techniques. Energy expenditure was assessed both by indirect ventilated hood calorimetry (resting energy expenditure) and the stable isotope doubly labelled water (2H2(18)O) technique (free living daily total energy expenditure). Mean increases in weight of 0.96 kg and fat free mass of 1.37 kg and a mean decrease in fat mass of 0.41 kg were observed. Significant increases both in resting energy expenditure and free living daily energy expenditure were detected. Absolute changes in fat mass and resting energy expenditure were correlated. The data suggest (i) that the increase in the fat free mass is the most significant early clinical measure of hGH response and (ii) that hGH increases the metabolic activity of the fat free mass. Monitoring such changes may be predictive of the efficacy of hGH in promoting growth.

Adolescent↗
PubMed1989

Dietary treatment of hyperlysinaemia.

We describe the lysine restricted, dietary management of three out of four siblings who were identified as having hyperlysinaemia. The diets, started in the neonatal period, were maintained for varying periods with unpredictable success. The propositus, who was not treated, was diagnosed at the age of 5 years, by which time he was already severely handicapped, presumably because of his metabolic disorder. Tentative recommendations are put forward for the management of this seemingly rare disorder. Mild chronic ammonia toxicity may be a factor in the pathogenesis of this condition.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

Inequality and mortality: demographic hypotheses regarding advanced and peripheral capitalism.

This paper analyzes mortality differences between social classes and between advanced and peripheral regions of the world economy. The demographic analysis of mortality is integrated with the study of political economy, which emphasizes the entire process of social reproduction. As part of this dialectic model, both the struggle of the working class to improve health and the interest of capital in maximizing profits are examined. Data from Québec and Upper Volta are used to illustrate the hypothesis that substantially higher mortality rates exist for the working class compared with the bourgeoisie and in the less developed peripheral regions compared with the more developed regions.

Adult↗