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Biomedical subjects

P T Pullan

Publications and source records attributed to P T Pullan.

At least 19 recordsLinked to original sources

Predictive diagnosis of multiple endocrine neoplasia (MEN 1) in four Australian kindreds.

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN 1) is a tumour predisposition syndrome that usually manifests in the first four decades of life. It has an autosomal dominant mode of inheritance which means that any new member of a MEN1 kindred has roughly a 50% chance of developing the disorder during their lifetime. The localisation of the MEN1 gene to a small region of chromosome band 11q13 has led to the development of DNA-based predictive diagnosis for this disease. AIMS: To establish a polymerase chain reaction (PCR)-based system, using simple tandem repeat polymorphisms (STRPs), to predict gene carriers in four Australian MEN 1 kindreds. METHODS: Six STRP markers flanking the MEN1 region of chromosome band 11q13 were used to screen individuals for a common haplotype in order to determine carrier status. RESULTS: The accuracy of prediction was calculated to be > 95% in informative individuals. CONCLUSIONS: DNA-based presymptomatic detection of affected members of MEN 1 kindreds could facilitate their care and reduce the inconvenience and expense of repeated testing of unaffected members. However, due to occasional recombination events or uninformativeness of markers in certain individuals, carrier status cannot always be predicted.

Adult

Increased central immunoreactive beta-endorphin content in patients with Wernicke-Korsakoff syndrome and in alcoholics.

beta-endorphin, adrenocorticotrophin, and alpha-melanocyte stimulating hormone were measured by radioimmunoassay in three areas of human brain at necropsy in seven subjects with Wernicke-Korsakoff syndrome and in 52 controls. Thiamin concentration in six brain areas was also measured. Mamillary body beta-endorphin concentrations were significantly increased in those with the syndrome compared with controls, and those controls with high alcohol intake showed increased mamillary body beta-endorphin compared with controls with low alcohol intake. Brain thiamin concentration was similar in both groups, with the exception of the brainstem, where it was reduced in subjects with Wernicke-Korsakoff syndrome. Thalamic beta-endorphin in controls was inversely correlated with thiamin in frontal white matter, frontal cortex, parietal white matter and parietal cortex, while beta-endorphin in the hypothalamus of patients was inversely correlated with thiamin in frontal cortex, parietal white matter, thalamus and brainstem. These results suggest that there is a disturbance of the endorphinergic system in Wernicke-Korsakoff syndrome which may be related to alcohol intake.

Adrenocorticotropic Hormone

Dystonia and intracerebral calcification: pseudohypoparathyroidism presenting in an eleven-year-old girl.

Pseudohypoparathyroidism is an uncommon cause of movement disorders. We describe the case of an otherwise well 11-year-old girl, who presented with dystonia and was subsequently shown to have the classical metabolic abnormalities of pseudohypoparathyroidism. Cranial computerised tomographic scanning (CT scanning) showed intracerebral calcification of the basal ganglia and frontal lobes.

Basal Ganglia Diseases

Fasting calcium excretion and parathyroid hormone together distinguish familial hypocalciuric hypercalcaemia from primary hyperparathyroidism.

Routine estimation of plasma calcium has made the finding of asymptomatic hypercalcaemia a frequent occurrence. A high index of suspicion for familial hypocalciuric hypercalcaemia (FHH) will lead to accurate diagnosis and avoidance of unnecessary parathyroid surgery. Four FHH kindreds with 16 hypercalcaemic members were found in an unselected referral population over 3 years. Differentiation from primary hyperparathyroidism (42 patients in the same period) was facilitated by analysis of fasting blood and urine for renal handling of calcium, phosphate and cyclic AMP. We found that a plot of serum PTH against fasting calcium excretion separated all cases of each disorder. The discriminatory power of these two variables was confirmed by multivariate discriminant function analysis. An elevated plasma chloride was found to be common to both diseases and of no value in differentiation.

Adult

Management of extra-sellar pituitary tumours with bromocriptine: comparison of prolactin secreting and non-functioning tumours using half-field visual evoked potentials and computerised tomography.

To determine whether prolactin secreting and non-functioning pituitary tumours respond differently in terms of shrinkage to bromocriptine, we prospectively studied ten consecutive patients (five with prolactinomas and five with non-functioning tumours) complicated by extra-sellar extensions. No patient had received prior radiotherapy or bromocriptine and the mean dose and duration of bromocriptine treatment were identical in the two groups of patients. Objective evidence of tumour shrinkage was provided by serial half-field visual evoked potentials (VEPs) and computerised tomography (CT). All five prolactinomas were shown to shrink as assessed by improvement in VEP and four of the five as assessed by CT. In contrast, only one of the five patients with non-functioning tumours showed any improvement in VEP or CT. Macroprolactinomas frequently shrink rapidly when treated with bromocriptine, whereas non-functioning tumours seldom show such a dramatic response.

Adult

Endogenous opiates modulate release of growth hormone in response to electroacupuncture.

The effect of electroacupuncture on serum growth hormone levels was investigated in 5 normal subjects and in 10 patients with chronic musculoskeletal pain. Serum growth hormone did not change in the normal subjects but there was an approximate 5-fold increase in the chronic pain subjects. This effect was partially inhibited by prior administration of the opiate antagonist naloxone, suggesting that the rise in growth hormone was mediated via release of central nervous system opioids.

Acupuncture Therapy

Adrenal suppression following extradural steroids.

Adrenocortical function was tested in 12 patients following a single lumbar extradural injection of methylprednisolone acetate ('Depo-Medrol') 80 mg as treatment for chronic sciatica. There was no absorption of the corticosteroid into the systemic circulation, but marked suppression of plasma cortisol levels was documented for up to 3 weeks following the injection and the capacity of the adrenal cortex to secrete cortisol in response to synthetic adrenocorticotrophin (ACTH) was diminished. These results suggest that the dose and frequency of extradural steroid administration should be kept to a minimum to prevent suppression of the hypothalamic/pituitary/adrenocortical axis and that patients thus treated should be considered candidates for steroid cover during surgery and other stressful procedures.

Adrenal Cortex

Drug management of antidiuretic hormone imbalance following pituitary surgery.

ADH imbalance may occur in patients after pituitary surgery. Two cases are presented that demonstrate the problems associated with the disturbance of water metabolism. The medical management of these patients is discussed, with emphasis on the importance of the correct choice of pharmacological agents to control the manifestations of ADH imbalance.

Aged

Ectopic production of methionine enkephalin and beta-endorphin.

Immunoreactive methionine enkephalin and beta-endorphin were sought by serial dilution of tissue extracts and assay of chromatographic fractions in non-endocrine tumour tissue from three patients with the ectopic adrenocorticotrophin syndrome associated with carcinoid tumours and in normal lung tissue and thymic tissue from a patient with myasthenia gravis. In all cases serial dilution of extracts showed parellelism to standard radioimmunoassay curves. The two peptides were found in high concentration in the three tumours but were undetectable in the control tissues. In a single case tested the methionine enkephalin concentration in a vein draining the tumour was twice that in a peripheral vein. In view of their profound effect on behaviour in animals and potent analgesic activity in animals and man the ectopic secretion of methionine enkephalin and beta-endorphin may modify the clinical features of a wide variety of tumours and produce some of the diverse clinical syndromes associated with malignancy.

ACTH Syndrome, Ectopic