Atrial fibrillation (AF) is associated with an increased risk of dementia and cognitive decline, independent of strokes. Several mechanisms have been proposed to explain this association, but altered cerebral blood flow dynamics during AF has been poorly investigated: in particular, it is unknown how AF influences hemodynamic parameters of the distal cerebral circulation, at the arteriolar and ...

The extraction of O-labeled water by the brain during a single capillary transit was studied in vivo in 20 adult rhesus monkeys by external detection of the time course of the tracer subsequent to the internal carotid injection of 0.2 ml of whole blood labeled with H,O. The data showed that labeled water does not freely equilibrate with the exchangeable water in the brain when the mean cerebral...

Whatever may be the nature of the nutritive error or deficiency which in chicks is responsible for encephalomalacia, the immediate cause must be looked for in some agent or condition which impairs the capillary circulation of the brain. The essential lesion is an ischemic necrosis, followed, if the animal survive, by reparative organization of the dead tissue.

A heat pipe is a self-contained structure which achieves very high thermal conductance by means of two-phase fluid flow with capillary circulation. A quantitative engineering theory for the design and performance analysis of heat pipes is given. iynC QUALITY INSPECTED 3 Aoe*8sloQ For HTIS GRAAI DTIC TAB Unannounced JuatLfloatloa. ■^ 0 a

M OST of the clinical investigation concerning nitroglycerin (glyceryl trinitrate) in recent years has centered about its influences on the coronary circulation and myocardial perfusion, and its cardiac effectiveness has recently been ascribed to a reduction in ventricular work.'-10 Widespread vasodilatation,l arterial, capillary, and venular, has been long recognized as one of the results of t...

The effects of prostaglandin E1 infusion on nailfold capillary haemodynamics were studied in eight patients with Raynaud's phenomenon secondary to progressive systemic sclerosis. Using a modified Landis microinjection technique the mean (+/- SEM) transcapillary pressure gradient was increased during and six weeks after infusion by 13.9 +/- 3.2 cm H2O (p less than 0.05) and 5.5 +/- 2.5 cm H2O (p...

• It has been suggested that circulatory failure in hemorrhagic shock is due in large part to a derangement of the peripheral circulation. The exact nature of this derangement is as yet obscure. It is known that arterial pressure is low and blood flow to many areas (e.g., skeletal muscle) is reduced. It is also known that one of the important compensatory mechanisms in shock is an increased sym...

Since the early work of Blumgart, Yens and Weiss (1 to 4) many methods have been recommended for measuring the circulation time in various segments of the circulation. In general, these methods have consisted of injecting a substance into an antecubital vein and noting its arrival either at the lung, as with the ether (5) and paraldehyde (6) tests, or at some point along the systemic circulatio...

Experiments were performed in 48 dogs subjected to a shock produced by hemorrhage after the modified Wiggers' method. Dogs were infused 90 minutes after hemorrhage with one of six test substances; shed blood, 5% glucose solution, or four kinds of dextran ( mw. 75,000, 47,000, 29,000 and 12,000 ). Infusion of dextran with mw. 29,000 produced the most remarkable increase in femoral arterial blood...

The choroidal circulation plays a central role in maintaining the health of outer retina and photoreceptor function. Alterations in this circulation contribute to pathogenesis of many eye diseases including exudative age-related macular degeneration. Unfortunately, very little is known about the choroidal circulation and its molecular and cellular regulation. This has been further hampered by t...