Search results for " blood flow"

Transmission of arterial oxygen partial pressure oscillations to the cerebral microcirculation in a porcine model of acute lung injury caused by cycl…

2013

Cyclic recruitment and derecruitment (R/D) play a key role in the pathomechanism of acute lung injury (ALI) leading to respiration-dependent oscillations of arterial partial pressure of oxygen (Pa(O(2))). These Pa(O(2)) oscillations could also be forwarded to the cerebral microcirculation.In 12 pigs, partial pressure of oxygen was measured in the thoracic aorta (Pa(O(2))) and subcortical cerebral tissue (Pbr(O(2))). Cerebral cortical haemoglobin oxygen saturation (Sbr(O(2))), cerebral blood flow (CBF), and peripheral haemoglobin saturation (Sp(O(2))) were assessed by spectroscopy and laser Doppler flowmetry. Measurements at different fractions of inspired oxygen (F(I(O(2)))) were performed …

Cerebral protection against ischemia by locomotor activity in gerbils. Underlying mechanisms.

1995

Background and Purpose A previous communication of this laboratory demonstrated reduced mortality and neuronal damage by spontaneous locomotor activity preceding forebrain ischemia in Mongolian gerbils. The present experiments seek to elucidate potential mechanisms of protection by measurement of cerebral blood flow, cerebral tissue conductance as an indicator of ischemic cell swelling, and the cerebral release of eicosanoids. Methods Gerbils were maintained either in conventional cages (nonrunners) or with free access to running wheels (runners) for 2 weeks preceding 15 minutes of forebrain ischemia. During ischemia and 2.5 hours of reperfusion, cerebral tissue conductance was determined …

Regional cerebral blood flow (rCBF) changes following local brain compression in the cat.

1968

Absorption of protein in the early postoperative period in chronic conscious dogs.

1988

Postoperative alterations in amino acid exchange across the intestinal tract and in the capacity for protein absorption were investigated in a chronic canine model. Changes in postoperative splanchnic amino acid exchange consisted of a temporary decrease of total splanchnic amino acid release, including a significant reduction in alanine production, and an increase in glutamine consumption. Contrary to results under stable metabolic conditions, branched chain amino acids were also taken up by the intestine in the early postoperative period. The changes in postoperative amino acid exchange were not, however, reflected by a corresponding alteration in protein transport capacity. The absorptiv…

Lipoic Acid Improves Nerve Blood Flow, Reduces Oxidative Stress, and Improves Distal Nerve Conduction in Experimental Diabetic Neuropathy

1995

OBJECTIVE To determine whether lipoic acid (LA) will reduce oxidative stress in diabetic peripheral nerves and improve neuropathy. RESEARCH DESIGN AND METHODS We used the model of streptozotocin-induced diabetic neuropathy (SDN) and evaluated the efficacy of LA supplementation in improving nerve blood flow (NBF), electrophysiology, and indexes of oxidative stress in peripheral nerves affected by SDN, at 1 month after onset of diabetes and in age-matched control rats. LA, in doses of 20, 50, and 100 mg/kg, was administered intraperitoneally five times per week after onset of diabetes. RESULTS NBF in SDN was reduced by 50% LA did not affect the NBF of normal nerves but improved that of SDN i…

Influence of the terminal complement-complex on reperfusion injury, no-reflow and arrhythmias: a comparison between C6-competent and C6-deficient rab…

1996

Objective: The complement system has been suggested to play a role in reperfusion injury which may result from an enhanced destruction of myocardial tissue or from an impairment of reflow. We investigated the influence of the C5b-9 complement complex on infarct size, reflow and arrhythmogenesis. Methods: Twenty-eight C6-competent rabbits and 18 rabbits with congenital C6 deficiency were subjected to either 30 min or 2 h of coronary artery occlusion followed by reperfusion. C6 deficiency was confirmed by the complement titration test and immunohistology. The triphenyl tetrazolium chloride method was used to delineate infarct size. Reflow into infarcted areas was evaluated histologically afte…

The Effect of Dexamethasone on Water and Electrolyte Content and on rCBF in Perifocal Brain Edema in Man

1972

The results of clinical studies are reported dealing with the relationship between cerebral edema and regional cerebral blood flow in patients with brain tumor as well as with the effect of dexamethasone on this relationship. rCBF is found to be significantly reduced in brain tissue surrounding brain tumors. Autoregulation as well as cerebrovascular reactivity to PaCO2 is focally or generally impaired. Water content of perifocal white matter is markedly increased. The combination of tissue lactacidosis, low regional blood flow and vasoparalysis seems to be a characteristic finding in this type of local brain edema. The increased local tissue pressure, due to the increased tissue water conte…

Possible Adverse Effects of Hyperventilation on rCBF during the Acute Phase of Total Proximal Occlusion of a Main Cerebral Artery

1969

Recent studies seem to favor a beneficial effect of hyperventilation (HV) in cases of cerebrovascular occlusion [1, 4] and brain trauma [2, 5]. On the other hand, it seems that, at least under certain circumstances, HV may exert an adverse effect upon cerebral blood flow and metabolism [3]. Since this question is not settled yet, it seems worthwhile to report briefly the present case of reversible total occlusion of the middle cerebral artery closely followed by successive rCBF studies (133Xe-gamma-clearance method), in which, during the acute phase, HV caused a latent ischemia to become manifest.

Cessation of Cerebral Blood Flow in Total Irreversible Loss of Brain Function

1969

After the demonstration, by our group [3, 4], that in cases of so-called “cerebral death” there is an absence of clearance from the brain of 133Xe selectively injected into the internal carotid artery, further attention was dedicated to establish possible sources of error in this technique.

Neuronal immunoreactivity for mannose-binding lectin after venous occlusion-induced focal cerebral ischemia in rats

2012

Abstract A recent research reveals that complement activation exacerbates cerebral infarction. However, involvement of the lectin pathway, (the third complement activation pathway) in cerebral ischemia is not well studied. In this study, we investigated the appearance of mannose-binding lectin (MBL) in ischemic brain tissue. Male Wistar rats ( n  = 25) were divided into three groups: untreated control, sham, and vein occlusion (VO). Rats in the VO group had two adjacent photochemically occluded cortical veins. Regional cerebral blood flow (rCBF) was measured in the sham and VO groups. Rats were perfusion-fixed at 72 h in the sham group and at 3, 24, and 72 h after inducing ischemia in the V…