English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Cerebral blood flow (CBF) was measured by  133 Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial P CO2  in eight normal men. Average arterial P CO2 , which was varied by giving 4% and 6% CO 2  in O 2  and by controlled hyperventilation on O 2 , ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF 15  were 27.2 and 65.0 ml 100 g min −1 , respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial P CO2  was described analytically by a parabola with the equation: [Formula: see text]    The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial P CO2  during O 2  breathing at rest. With respect to baseline values measured while breathing 100% O 2  spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial P CO2  and larger than CBF changes at the lower arterial P CO2 . These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

Relationship of 133Xe Cerebral Blood Flow to Middle Cerebral Arterial Flow Velocity in Men at Rest

Relationship of ¹³³Xe Cerebral Blood Flow to Middle Cerebral Arterial Flow Velocity in Men at Rest