BACKGROUND/AIM Transient global amnesia (TGA) could be related to acute ischemic disturbances in mesial parts of temporal lobes, which are important for memory. Incompetence of internal jugular vein (IJV) valve with venous congestion causes venous microthrombosis of hippocampus. The aim of this study was to investigate the frequency of IJV valve incompetence, as well as other hemodynamic and st...

Aging occurs with enhanced sympathetic nerve activity and endothelial dysfunction; however, little is known of how successive branches of microvascular resistance networks are affected in vivo. We questioned whether vascular reactivity is altered differentially along resistance networks with advanced age. The left gluteus maximus muscle of anesthetized 4-mo-old and 24-mo-old male C57BL/6 mice (...

BACKGROUND AND PURPOSE The acetazolamide provocation test is commonly used to study cerebrovascular vasomotor reactivity. On the basis of the effect of a carbonic anhydrase inhibitor in the central nervous system, we hypothesized that acetazolamide may also increase blood flow in the human choroid. METHODS In a placebo-controlled, randomized, double-blind, three-way crossover design, acetazol...

Mitsis, Georgios D., Rong Zhang, Benjamin D. Levine, and Vasilis Z. Marmarelis. Cerebral hemodynamics during orthostatic stress assessed by nonlinear modeling. J Appl Physiol 101: 354–366, 2006. First published March 2, 2006; doi:10.1152/japplphysiol.00548.2005.—The effects of orthostatic stress, induced by lower body negative pressure (LBNP), on cerebral hemodynamics were examined in a nonline...

The effects of orthostatic stress, induced by lower body negative pressure (LBNP), on cerebral hemodynamics were examined in a nonlinear context. Spontaneous fluctuations of beat-to-beat mean arterial blood pressure (MABP) in the finger, mean cerebral blood flow velocity (MCBFV) in the middle cerebral artery, as well as breath-by-breath end-tidal CO2 concentration (P(ET(CO2))) were measured con...

Cerebral vasomotor reactivity (CVMR) to changes in arterial carbon dioxide tension (P aCO 2) is assessed during steady-state or transient changes in P aCO 2. This study tested the following two hypotheses: (i) that CVMR during steady-state changes differs from that during transient changes in P aCO 2; and (ii) that CVMR during rebreathing-induced hypercapnia would be blunted when preceded by a ...