Enhanced myogenic tone in cerebral arteries from a rabbit model of subarachnoid hemorrhage.

Cerebral artery vasospasm is a major cause of death and disability in patients experiencing subarachnoid hemorrhage (SAH). Currently, little is known regarding the impact of SAH on small diameter (100-200 microm) cerebral arteries, which play an important role in the autoregulation of cerebral blood flow. With the use of a rabbit SAH model and in vitro video microscopy, cerebral artery diameter was measured in response to elevations in intravascular pressure.

Pituitary tumor diagnosis and treatment.

Over the past few years, significant contributions have been made to the understanding, diagnosis, and treatment of pituitary tumors. This article reviews recent advances in the areas of biology, diagnostic imaging, medical diagnosis and treatment, surgical results and technique, and adjuvant therapy in the form of radiotherapy and radiosurgery. Of particular note are the roles of endoscopy, intraoperative magnetic resonance imaging, radiosurgery, and radiation for nonfunction tumors, the diagnosis of Cushing's disease, the management of "incidentalomas," and new medication therapies.

Ca2+ sparks and their function in human cerebral arteries.

Background And Purpose: Local Ca2+ release events (Ca2+ sparks) caused by the opening of ryanodine-sensitive Ca2+ channels in the sarcoplasmic reticulum have been suggested to oppose constriction in cerebral arteries through the activation of large-conductance Ca2+-activated K+ (BK) channels. We report the first identification and characterization of Ca2+ sparks and associated BK channel currents in smooth muscle cells isolated from human cerebral arteries.

Methods: Membrane currents and intracellular Ca2+ were measured with the use of the patch-clamp technique and laser scanning confocal microscopy.