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Biomedical subjects

P Hindmarsh

Publications and source records attributed to P Hindmarsh.

47 records · Page 3Linked to original sources

Abnormal pubertal development in primary hypothyroidism.

We have studied three patients (1M, 2F), age range 10.9 to 15.5 years, who had abnormal sexual maturation secondary to primary hypothyroidism. The boy had inappropriately large testes for his stage of puberty, the girls had isolated breast development and there was absence of pubertal growth acceleration. FSH, LH, TSH and GH secretion, pituitary imaging and ovarian ultrasound morphology were studied before and during thyroxine treatment. In the hypothyroid state, FSH levels were elevated with abnormal pulsatility and LH:FSH concentrations were reversed.

Adolescent↗

The relationship between height velocity and growth hormone secretion in short prepubertal children.

We have performed 24 h growth hormone (GH) profiles in 50 short prepubertal children aged between 5.2 and 12.9 years, growing with height velocity standard deviation scores (SDS) between 0.4 and -3.9. There was an asymptotic relationship between height velocity and spontaneous GH secretion described by the equation: height velocity SDS = A-B(e-cx), where A, B and C are constants and x is a measure of spontaneous GH secretion. We considered GH pulse amplitude to be the better description of spontaneous GH secretion as duration of the GH pulse (the time component of area under the curve) contributed little to the relationship between height velocity and area under the pulse. The distribution of GH secretion was continuous and there was no dividing point between GH insufficiency and sufficiency. Similar overlap was observed when the results of GH responses to insulin induced hypoglycaemia were considered; 14% of slowly growing children (height velocity SDS less than -0.8), had a response greater than 15 mU/l. Likewise serum IGF-I concentrations could not clearly separate slowly growing children from normal individuals. We conclude that height velocity, which ultimately determines height achieved, is controlled predominantly by GH pulse amplitude. The findings suggest that short normal children growing along or parallel to the third height centile could be made to grow faster by the administration of exogenous GH.

Body Height↗

Oxandrolone induces a sustained rise in physiological growth hormone secretion in boys with constitutional delay of growth and puberty.

We describe the treatment of 3 boys, mean age 14.9 years (range 13.8-16.1 years) with constitutional delay of growth and puberty using oxandrolone in two dose regimens, 2.5 or 1.25 mg/day for 3 months. Treatment induced an increase in mean height velocity from 5.1 to 8.5 cm/year; this was sustained at 8.8 cm/year in the period following treatment. Growth hormone (GH), luteinising hormone and testosterone secretion were assessed by overnight or 24-hour venous sampling at 15-min intervals before, during treatment and after cessation of treatment. A computer programme was used to analyse GH secretory dynamics. The 3 boys had a mean sustained increase in total GH secretion of 190%. The increase in GH secretion was associated with an increase in amplitude of GH pulses rather than an alteration in pulse frequency.

Adolescent↗

High resolution CT scanning of the pituitary gland in growth disorders.

We have performed 217 GEC 8800 CT scans of the hypothalamus and pituitary glands of 202 children with disorders of growth and development. Pituitary morphological abnormalities were common. Intrapituitary low density lesions were found in 17% of the whole series and in 58% of children with tall stature. Seventy-seven children with idiopathic growth hormone deficiency could be divided on the basis of pituitary morphology seen on CT scan into pituitary aplasia (n = 11) and pituitary hypoplasia (n = 53). Patients with pituitary aplasia had an absent adenohypophysis which probably dated from early intrauterine life and therefore could not be related to birth trauma. We have found a high incidence of evolving endocrinopathy in children with pituitary insufficiency: thus, if a short child is investigated the initial endocrine findings need to be repeated as the pattern of pituitary insufficiency changes with time. An evolving endocrinopathy starting in later childhood is suggestive of the presence of a cerebral tumour. Children with subnormal growth velocities and a normal growth hormone response to pharmacological tests have a wide spectrum of pituitary morphological abnormalities which may be associated with growth hormone neurosecretory dysfunction.

Adolescent↗

Dysgenesis of the corpus callosum and hypopituitarism.

A high resolution CT scan demonstrated the unexpected finding of dysgenesis of the corpus callosum in addition to the expected finding of pituitary hypoplasia in three children who presented with growth failure secondary to hypopituitarism. Several of the clinical features reported in association with dysgenesis of the corpus callosum may be ascribed to hypothalamo-pituitary dysfunction. These children emphasize the need to assess the endocrine function of patients with midline structural defects. It should not be assumed that the clinical manifestations are related solely to the anatomical abnormality.

Agenesis of Corpus Callosum↗