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Biomedical subjects

A C Fok

Publications and source records attributed to A C Fok.

25 records · Page 2Linked to original sources
PubMed1991

Overnight (1 mg) dexamethasone suppression testing reliably distinguishes non-cushingoid obesity from Cushing's syndrome.

To determine the sensitivity of the overnight 1-mg dexamethasone suppression test in diagnosing Cushing's syndrome, we evaluated the cortisol responses of 55 subjects (25 non-obese individuals with body mass index less than 25 kg/m2, 20 obese individuals with body mass index greater than 30 kg/m2, and 10 patients with surgically proven Cushing's syndrome) following ingestion of 1 mg dexamethasone at midnight. The basal 8 AM plasma cortisol levels among non-obese and obese individuals and patients with Cushing's syndrome were 310 +/- 85, 377 +/- 91, and 813 +/- 270 nmol/L, respectively. Following 1 mg of dexamethasone, Cushing's syndrome patients showed minimal suppression of cortisol to 609 +/- 180 nmol/L (P = 0.79). Non-obese and obese individuals suppressed to 18.7 +/- 6.0 nmol/L (P less than 0.001) and 22 +/- 7.1 nmol/L (P = 0.003), respectively. The results demonstrated similar cortisol responses to overnight dexamethasone suppression in obese and non-obese groups, and clearly distinguished these subjects from those with Cushing's syndrome. Obesity is not a confounding factor in the 1-mg dexamethasone suppression test.

Adult↗
PubMed1989

Restoration of spermatogenesis with pulsatile gonadotrophin releasing hormone therapy in hypogonadotrophic hypogonadism of traumatic etiology.

Head trauma is one of the rarest reported causes of hypogonadotrophic hypogonadism and treatment of this condition with pulsatile gonadotrophin releasing hormone (GnRH) has not been previously described. A 36-year-old man with azoospermia from hypogonadotrophic hypogonadism following head trauma was given pulsatile GnRH therapy. 10 micrograms of GnRH was administered every 90 minutes through a subcutaneous catheter in the abdominal wall. After 15 months, the ejaculate contained 34 x 10(6) spermatozoa/ml of semen. Prolonged pulsatile GnRH therapy can restore gonadal function in males with hypogonadotrophic hypogonadism of traumatic etiology. Our experience adds to the growing spectrum of hypothalamic disorders causing hypogonadism that is amenable to treatment by this method.

Adult↗
PubMed1989

Syndrome of cerebellar ataxia and hypogonadotrophic hypogonadism: evidence for pituitary gonadotrophin deficiency.

Familial cerebellar ataxia with hypogonadotrophic hypogonadism is a rare condition. Two affected siblings in a sibship of three were studied and found to have low plasma gonadotrophin levels. No rise in gonadotrophin levels was demonstrable after repeated stimulation with LHRH. The pattern of TSH and prolactin responses to TRH stimulation suggest hypothalamic dysfunction. The results clearly identify the cause of hypogonadism to be due to a defect in production or release of gonadotrophins by the pituitary gland and suggest that hypogonadism is part of a greater endocrine disturbance involving both the hypothalamus and pituitary.

Adolescent↗
PubMedDate not supplied

Cushing's syndrome in a patient with a corticotropin-releasing hormone-producing pheochromocytoma.

OBJECTIVE: To present the first case of Cushing's syndrome attributable solely to ectopic production of corticotropin-releasing hormone by a pheochromocytoma. METHODS: We summarize the clinical features and results of laboratory investigations in a patient with symptoms characteristic of Cushing's syndrome. RESULTS: Although Cushing's syndrome is usually caused by ectopic production of adrenocorticotropic hormone (ACTH), our current patient had clinical and biochemical evidence of hypercortisolism in conjunction with "normal" ACTH levels and nonsuppressible serum and urinary cortisol levels on low-dose and high-dose dexamethasone suppression testing. An abdominal computed tomographic scan revealed a 7.7-cm mass in the left adrenal gland. Light microscopic examination and immunohistochemical staining showed a pheochromocytoma with mild cortical hyperplasia. Immunostaining was positive for corticotropin-releasing hormone but negative for ACTH. CONCLUSION: To our knowledge, this is the first case of Cushing's syndrome in a patient with pheochromocytoma caused only by ectopic secretion of corticotropin-releasing hormone without accompanying secretion of ACTH.

Journal Article↗