It is believed that adenosine is released in ischemic tissues and contributes to reactive hyperemia. We tested this hypothesis in the human forearm using microdialysis to estimate interstitial and intravascular levels of adenosine and caffeine withdrawal to potentiate endogenous adenosine and determine its effect on reactive hyperemia. Forearm blood flow response to ischemia was measured by air...

Ischemia impairs blood supply to the brain, and reperfusion is important to restore cerebral blood flow (CBF) and rescue neurons from cell death. However, reperfusion can induce CBF values exceeding the basal values before ischemia. This hyperemic effect has been associated with a worse ischemic brain damage, albeit the mechanisms that contribute to infarct expansion are not clear. In this stud...

OBJECTIVE Vascular impairment, a main feature of the pathogenesis of systemic sclerosis (SSc), involves both the macro- and the microvasculature. We compared and correlated simultaneously measured skin microvascular and brachial artery macrovascular post-occlusive hyperemia in 3 groups: patients with SSc, patients with primary Raynaud's phenomenon (RP), and healthy volunteers. METHODS Thirty-...

Endothelial function is known to be impaired in essential hypertensive patients. In this study, we examined whether antihypertensive drugs improve forearm vasodilatory response to reactive hyperemia in 26 patients with essential hypertension (62 +/- 2 years) without diabetes mellitus, hyperlipidemia, coronary heart disease, or cerebrovascular disease. Antihypertensive drugs were never given or ...

Neuronal activity leads to arteriole dilation and increased blood flow in retinal vessels. This response, termed functional hyperemia, is diminished in the retinas of diabetic patients, possibly contributing to the development of diabetic retinopathy. The mechanism responsible for this loss is unknown. Here we show that light-evoked arteriole dilation was reduced by 58% in a streptozotocin-indu...

Objective Measuring the fractional flow reserve (FFR) requires the induction of coronary hyperemia, usually with adenosine, adenosine triphosphate (ATP), or papaverine. However, adenosine can induce rhythmic complications, and intracoronary boluses of papaverine that prolong the QT interval can cause ventricular tachycardia. Injection of contrast media, which is routinely performed to validate ...

Reactive hyporcmia in the finger was investigated in 16 experiments on 5 normal subjects, using venous occlusion plethysmography. Since the flow is so variable from moment to moment, the simultaneous "corrected" flow in a control finger, not occluded, was subtracted from tho flow in the test finger, so the difference gave the effect of occlusion free from fluctuations of central origin. The abs...