Search PubMed⌕ Search

Biomedical subjects

J B Tyrrell

Publications and source records attributed to J B Tyrrell.

11 recordsLinked to original sources
PubMed1978

Cushing's disease. Selective trans-sphenoidal resection of pituitary microadenomas.

We undertook trans-sphenoidal microsurgical pituitary exploration in 20 consecutive patients with Cushing's disease, eight of whom had normal sellar polytomography. Pituitary adenomas were selectively resected in 17 and histologically confirmed in 14. In one patient total hypophysectomy revealed a 1.5-mm basophilic adenoma, and in two patients vascular anomalies prevented sellar exploration. Hypercortisolism was corrected in 17 patients (i.e., in 16 of the 17 undergoing selective tumor removal and in the one with total hypophysectomy). Panhypopituitarism occurred only in this patient, and transient diabetes insipidus occurred in five. Most patients became glucocorticoid deficient and required replacement therapy. We conclude that pituitary tumors are present in the great majority of patient with Cushing's disease, even in the absence of demonstrable tomographic changes in the sella turcica, and that selective removal corrects hypercortisolism with little morbidity.

Adenoma↗
PubMed1977

Cushing's disease: growth hormone response to hypoglycemia after correction of hypercortisolism.

Growth hormone responses to insulin-induced hypoglycemia were studied in 17 patients with inactive Cushing's disease. A normal GH rise was found in 9 of 9 patients without evidence of progressive pituitary tumor after bilateral adrenalectomy and 3 of 4 patients after correction of hypercortisolism by transsphenoidal removal of pituitary microadenomas. In contrast, 3 of 4 patients with Nelson's syndrome had impaired GH responsiveness to hypoglycemia. These results show that GH responsiveness is normal in the majority of patients with inactive Cushing's disease and do not support the concept of a primary hypothalamic or central nervous system abnormality of GH regulation in Cushing's disease.

Adrenalectomy↗
PubMed1977

Plasma adrenocorticotropin levels in normal dogs.

Plasma concentrations of adrenocorticotropin (ACTH; corticotropin) were measured in 31 normal dogs (house pets) at rest. The mean concentration was 45.77 pg/ml of blood, with individual values ranging from 17 to 98 pg/ml of blood. The measurement of this hormone secreted by the anterior lobe of the pituitary gland (adenohypophysis) may aid in the diagnosis of spontaneous canine adrenal cortical disorders, both primary and secondary.

Adrenal Cortex Hormones↗
PubMed1975

Inhibition by somatostatin of ACTH secretion in Nelson's syndrome.

Somatostatin (GHIF), when administered as a 1-hr infusion (500 mug/hr) to 5 patients with Nelson's Syndrome;resulted in a sustained, progressive fall in plasma ACTH in each patient to 40% to 71% of basal values with a return toward initail levels after cessation of the infusion. The meanreduction in plasma ADTH was 48% (p less than 0.005). These finding suggest that GHIF receptors not fuctional or present in normal pituitary tissue are present in ACTH-producing pituitary tumors.

Adenoma↗