Search PubMed⌕ Search

Biomedical subjects

A M Lawrence

Publications and source records attributed to A M Lawrence.

At least 127 records · Page 7Linked to original sources
PubMed1979

The continued importance of adrenalectomy in the treatment of Cushing's disease.

Eighteen patients with pituitary-dependent Cushing's disease have been treated during a ten-year period. Eleven of these received a total of 14 alternative forms of therapy in an attempt to control the clinical manifestations of Cushing's disease prior to adrenalectomy. However, no substantial improvement was noted in these patients, who included four receiving conventional pituitary irradiation, five receiving cyproheptadine, two receiving mitotane, and one each receiving metyrapone and phenytoin. One patient had an attempted transsphenoidal hypophysectomy that could not be accomplished because of hemorrhage. A complete remission of the signs, symptoms, and laboratory abnormalities of Cushing's disease occurred in all 18 patients following bilateral adrenalectomy. There was no operative mortality and morbidity was minimal. This experience confirms that bilateral adrenalectomy is a rapid, safe, and permanent means of reversing hypercortisolism and that it should remain an integral part of the treatment of Cushing's disease.

Adolescent↗
PubMed1978

Biologically active pituitary hormones in the rat brain amygdaloid nucleus.

While an attempt was being made to identify the source of the growth hormone releasing factor present in cerebral spinal fluid of man, it was discovered that cells of the rat amygdaloid nucleus, grown in tissue culture, produce a material that is immunologically and chromatographically identical to growth hormone found in the pituitary. Immunoperoxidase staining revealed dense accumulation of the peroxidase-antibody to growth hormone complex in amygdala cells. Significant amounts of growth hormone and adrenocorticotropin could be extracted from this limbic structure. Extracts containing immunoequivalent amounts of growth hormone were measured by bioassay in hypophysectomized rats. Stimulation of the growth of epiphyseal cartilage by extracts of the amygdala was comparable to the stimulation by extracts of anterior pituitary glands. The stimulatory effect of amygdala extracts on adrenal and gonadal size and weight and on growth of thyroid follicular epithelium was also comparable to that of pituitary extracts.

Adrenal Glands↗
PubMed1978

Preliminary studies of plasma growth hormone releasing activity during medical therapy of acromegaly.

The in vitro growth hormone releasing activity of plasma obtained from six acromegalic subjects was measured before and during therapy. In five subjects, plasmas were obtained before and during successful medical therapy with medroxyprogesterone acetate (MPA). The sixth subject was sampled before and after transphenoidal Sr90-induced hypopituitarism. All subjects had a decrement in fasting growth hormone levels with respective therapies (29-88%). The in vitro growth hormone released from Rhesus monkey anterior pituitaries was assessed after incubating one lateral half in control plasma (pre-therapy) and the contralateral pituitary half in plasma obtained during or after therapy. Studies with plasmas obtained from the five patients successfully treated with MPA showed a decreased in growth hormone releasing activity during therapy in all (18-57%). Plasma obtained after Sr90 pituitary ablation in the sixth subject had 35% more growth hormone releasing activity than obtained before therapy. These results suggest that active acromegalics who respond to MPA with significantly lowered growth hormone levels may actually achieve this response because of a decrease in growth hormone releasing factor measured peripherally. The opposite response in one acromegalic subject, following Sr90 pituitary ablation and hypopituitarism, suggests that growth hormone releasing factor secretion may increase when growth hormone levels are lowered by ablative therapy.

Acromegaly↗
PubMed1978

Thyroid neoplasms after radiation therapy for adolescent acne vulgaris.

There is a potential hazard of thyroid cancer after exposure to external irradiation for the treatment of adolescent acne vulgaris. We noted a 60% incidence of thyroid carcinoma among 20 patients with such a history, who were operated on for thyroid nodules during a five-year period. Eighty-three percent of the patients with carcinoma had either a follicular or a mixed papillary-follicular carcinoma; 17% had a papillary carcinoma; 33% had regional node metastases; none had evidence of distant metastases. The interval between radiation exposure and thyroidectomy ranged from nine to 41 years. This association of thyroid neoplasms and a prior history of radiation for acne vulgaris may be coincidental and therefore remains to be proved by retrospective surveys of large numbers of treated patients with appropriate controls.

Acne Vulgaris↗
PubMed1977

Salivary gland hyperglycemic factor: an extrapancreatic source of glucagon-like material.

Extracts of homogenates of rat, mouse, rabbit, and human submaxillary salivary glands contain a significant quantity of a material with glucagon-like immunoreactivity. Fractionation of this material on columns of Sephadex G-100 reveals a single peak immediately following a gamma globulin marker but in advance of a rat growth hormone marker, crystalline amylase, and isotopically labeled porcine insulin and glucagon. This material, which is urea stable, shows identical immunoassay dilution curves when measured with the highly specific K-30 glucagon antiserum. Study of paired glands in vitro shows that low concentrations of glucose stimulate and high concentrations of glucose suppress release of this material. Arginine promotes brisk release in vitro. Somatostatin does not influence arginine-stimulated secretion and insignificantly suppresses basal release in vitro. These findings lend support to previous speculations that the salivary glands may possess endocrine as well as exocrine functions. Salivary gland glucagon may also be the source of circulating glucagon recently reported in pancreatectomized and eviscerated rats.

Animals↗
PubMed1977

Improved tolerance to successive glucose loads in acromegaly.

The mechanism of the Staub-Traugott effect, or facilitated glucose disposal with closely timed successive glucose loads, remains poorly understood. Progressive suppression of growth hormone has been suggested as an explanation. To test this hypothesis, three successive intravenous glucose loads were administered to seven active acromegalic patients and six healthy controls. All subjects showed a clear Staub-Traugott effect despite failure of hyperglycemia to suppress abnormally high growth hormone levels in the acromegalics. Except for higher basal and incremental insulin release in the acromegalic patients, patterns of insulin secretion and suppression of free fatty acids were not substantially different from controls. These studies clearly suggest that hyperglycemia-induced suppression of growth hormone is not the cause of the Staub-Traugott effect.

Acromegaly↗
PubMed1977

Hypothalamic hypopituitarism after pituitary apoplexy in acromegaly.

Pituitary apoplexy in acromegaly is an uncommon event having been recorded approximately 30 times in the English literature. This report records two additional cases that included growth hormone measurements and an assessment of pituitary function. The apoplectic event developed spontaneously in one, and in the other it developed within two weeks of completing a course of radiotherapy to the pituitary gland. Autocure of the acromegaly was apparent. Basal levels of growth hormone were in the normal range but failed to change with provocative stimuli. Luteinizing hormone and follicle-stimulating hormone titers, although detectable, were inappropriately low for the degree of hypogonadism. Pituitary insufficiency was associated with a significant thyroid-stimulating hormone response to protirelin in one patient tested. It is suggested that these experiments of nature lend credence to the proposal that the hypothalamus may play a critical role in the perpetuation of growth hormone hypersecretion in some patients with acromegaly.

Acromegaly↗
PubMed1977

Successful autotransplantation of the parathyroid glands during total thyroidectomy for carcinoma.

In a consecutive series of 118 total thyroidectomies during a period of 11 years, autotransplantation of one or more parathyroid glands was used in 64 patients. During the first nine years of this series, autotransplantation was used in only 25 per cent of the total thyroidectomies, with a 3 per cent incidence of permanent hypoparathyroidism. During the last two years, autotransplantation of the parathyroid was used in 89 per cent of 54 total thyroidectomies, with a zero incidence of hypoparathyroidism.

Adolescent↗
PubMed1976

Total thyroidectomy and parathyroid autotransplantation for radiation-associated thyroid cancer.

In seventy patients with nodular thyroids and a history of radiation exposure, total thyroidectomy disclosed a 54% incidence of carcinoma; more than half of them had cervial node metastases; four had distant metastases. Fourteen patients required radical neck dissection. The carcinoma was multicentric (both lobes) in 45%. In four patients the carcinoma was found in the lobe contralateral to the one containing the palpable nodule. These findings support the advocates of total thyroidectomy for patients with a nodular thyroid and a history of radiation exposure, provided this operation can be performed with a low incidence of recurrent nerve palsy and hypoparathyroidism.

Adolescent↗