Human adrenal glands secrete vitamin C in response to adrenocorticotrophic hormone.

Background: When vitamin C intake is from foods, fasting plasma concentrations do not exceed 80 micromol/L. We postulated that such tight control permits a paracrine function of vitamin C.

Objective: The purpose of this study was to determine whether paracrine secretion of vitamin C from the adrenal glands occurs.

MR imaging features of thyrotropin-secreting pituitary adenomas at initial presentation.

Objective: We report the MR imaging characteristics of thyrotropin-producing pituitary adenomas at their initial presentation and also report the role of MR imaging in predicting surgical outcome in these rare tumors.

Materials And Methods: We reviewed the records and MR images of 21 patients with thyrotropin-producing pituitary adenomas from 1984 to 1999. The imaging features of these tumors were examined, including enhancing characteristics and tumor volumes.

Persistent primary hyperparathyroidism caused by adenomas identified in pharyngeal or adjacent structures.

Abnormalities in the normal migration of the parathyroid glands during embryological development of the head and neck may result in considerable variability in the location of parathyroid tissue. Ectopic parathyroid adenomas present diagnostic and technical challenges and are frequently the cause of persistent primary hyperparathyroidism (HPT) after unsuccessful initial parathyroid surgery. We report a series of eight patients with persistent primary HPT who had adenomas in rare and unusual locations associated with various pharyngeal structures.

Successful management of spinal dural arteriovenous fistulas undetected by arteriography. Report of three cases.

Spinal dural arteriovenous fistulas (AVFs) frequently cause progressive myelopathy. When they are localized by imaging studies, surgery can be safely performed by simply interrupting the vein draining the fistula intradurally, and the results will be excellent and lasting. In some patients with clinical features of a spinal dural AVF and in whom magnetic resonance imaging and/or myelography findings are consistent with a diagnosis of a spinal dural AVF, however, spinal arteriography demonstrates no such results.