The viability of dental pulp depends largely on regional blood flow, as in other organs. Measurement of absolute pulpal blood flow (PBF) and comparisons with blood flow in other organs allow the prediction of microvascular regulation in dental pulp. In previous studies, PBF was measured in dogs mainly with radioactive microspheres. However, this established technique is inaccessible to many inv...

The changes in myocardial high energy phosphates and pH during regional ischemia, and their potential role in mediating functional abnormalities, is unclear. To determine the degree of regional blood flow reduction required to induce changes hi high energy phosphates and pH, and to correlate these metabolic changes with alterations hi blood flow, P nuclear magnetic resonance spectroscopy was em...

A major determinant of oxygen transport to the myocardium is the time spent by the erythrocytes (red blood cells [RBCs]) traversing the microcirculation. Although it has been shown that the myocardium has regional differences in blood volume, blood flow, metabolism, and sensitivity to ischemic injury, the regional distribution of RBC transit times through the myocardial capillaries has not been...

PURPOSE To assess the role of regional cerebral blood flow measured by technetium-99m hexamethyl propyleneamine oxime (HMPAO) brain single-photon emission CT (SPECT) in viral encephalitis of children. METHODS Eighteen children diagnosed as having viral encephalitis (12 Epstein-Barr virus, 4 herpes simplex virus, and 2 Japanese B virus) underwent Tc-99m HMPAO brain SPECT and brain MR and/or CT...

OBJECTIVE Acute respiratory dysfunction frequently occurs following severe aneurysmal subarachnoid hemorrhage requiring positive end-expiratory pressure (PEEP) ventilation to maintain adequate oxygenation. High PEEP levels, however, may negatively affect cerebral perfusion. The goal of this study was, to examine the influence of various PEEP levels on intracranial pressure, brain tissue oxygen ...

We measured regional cerebral blood flow and acetylcholine and choline concentrations in tissue fragments of normally perfused and ischemic cortical regions from 10 rats. Tissue uptake of [14C]iodoantipyrine was used to indicate regional cerebral blood flow, and gas chromatography-mass spectrometry was used to measure acetylcholine and choline concentrations. Cerebral cortical ischemia was indu...

Regional cerebral blood flow was studied by means of the Xe inhalation method hi 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal region...

BACKGROUND AND PURPOSE This study sought to determine the degree of agreement between asymmetries of neuropsychological functioning and nine methods of quantifying asymmetries of regional cerebral blood flow. METHODS The regional cerebral blood flow methods combined three markers of cerebral blood flow asymmetry (percent hemispheric difference, maximum percent probe-pair asymmetry, and number...

We used quantitative Single Photon Emission Computed Tomography (SPECT) to study the effect of the upright posture on regional lung blood flow and ventilation. Nine (upright) plus seven (prone and supine) healthy volunteers were studied awake, breathing spontaneously. Regional blood flow and ventilation were marked in sitting upright, supine and prone postures using (113m)In-labeled macroaggreg...

The effect of pulmonary blood flow on the exchange between the circulating was marginating pool of polymorphonuclear leukocytes (PMN) was examined in three sets of experiments. In the first we used the double indicator dilution technique with labeled PMN and erythrocytes (RBC) to calculate the percent extraction and percent recovery of PMN at different levels of cardiac output (CO). In the seco...