ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

The possibility that cerebral ischemia may initiate a series of pathological free radical reactions within the membrane components of the CNS was investigated in the cat. The normally occurring electron transport radicals require adequate molecular oxygen for orderly transport of electrons and protons. A decrease in tissue oxygen removes the controls over the electron transport radicals, and allows them to initiate pathologic radical reactions among cell membranes such as mitochondria. Pathologic radical reactions result in multiple products, each of which may be present in too small a concentration to permit their detection at early time periods. It is possible to follow the time course, however, by the decrease of a major antioxidant as it is consumed by the pathologic radical reactions. For this reason, ascorbic acid was measured in ischemic and control brain following middle cerebral artery occlusion. There was a progressive decrease in the amount of detectable ascorbic acid ranging from 25% at 1 hour to 65% at 24 hours after occlusion. The reduction of this normally occurring antioxidant and free radical scavenger may indicate consumption of ascorbic acid in an attempt to quench pathologic free radical reactions occurring within the components of cytomembranes.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A series of 9 patients have experienced hemisphere and retinal ischemia at an interval after occlusion of appropriate internal carotid arteries. All had radiological evidence of a persisting proximal stump to the occluded artery and, in most, pathological evidence of thrombotic material attached to atheromatous lesions within the stump. Thromboembolism from the stump via the anastomotic supply through ipsilateral common and external carotid arteries is thought to be responsible for the ischemic events to the brain or retina despite absence of flow through the internal carotid artery. Seven of the 9 were treated by surgical excision or obliteration of the stump and, when indicated, common and external carotid endarterectomy. Turbulence in the stump contributed to progressive atherosclerotic changes and probably aggravated thrombogenesis in this location with subsequent embolization into the anastomotic arteries.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Two patients with transient ischemic attacks and subsequent minor cerebral infarction had repair of very tight carotid stenosis, 4 and 5 weeks respectively after their stroke. Each developed intracerebral hemorrhage when hypertension was uncontrolled during the post-operative period. Hypertension is a significant complication of carotid endarterectomy, and may be a prominent factor in the development of intracerebral hemorrhage post-carotid endarterectomy.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Unilateral permanent occlusion of the proximal part of the middle cerebral artery (MCA) was performed in 24 dogs. End-to-side anastomosis of the maxillary artery (MA) and a branch of the MCA on the occluded side was made 4 hours later in 8 dogs (prompt bypass group), and 3 weeks later in 5 dogs (delayed bypass group) using an operating microscope. The other 11 dogs without MA/MCA anastomosis were used as controls. A common carotid angiogram of control animals was done 2 to 5 weeks after the occlusion, and a selective external carotid angiogram of animals with an anastomosis was done 2 weeks after making an MA/MCA anastomosis. When the animals were killed, transcarotid perfusion was carried out, and the brains examined histologically. Eight of the 11 control animals showed mild to severe neurological defects, the other 3 died. In contrast, animals with patent bypass grafts, made soon after the MCA occlusion, showed no neurological defects. Examination of the brains of control dogs showed that permanent occlusion caused medium to large infarcts in the territory supplied by the occluded MCA. Of the 8 dogs in the prompt bypass group, only 1 had an occluded bypass, and among the 7 dogs with a patent prompt bypass, 1 had no infarct and 6 had small infarcts detected microscopically. In the group with a patent delayed bypass, the clinical features were similar to those of the controls, but on postmortem examination the infarcts were found to be smaller than those in control animals. No hemorrhagic infarcts were found in either the prompt or delayed bypass group. Results suggest that re-establishment of blood flow by construction of an extracranial-intracranial bypass, particularly if done soon after MCA occlusion, may be valuable for restoring neurological functions without causing appreciable pathological damage to the brain.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A non-invasive method is described for visualizing the carotid bifurcation using a continuous-wave Dopplershift technique simultaneously with spectral analysis of the blood velocities from all parts of the vessel lumen. The system is directional so that arteries can be visualized in the presence of signals from adjacent veins. The technique uses a transducer which is attached to a position-sensing arm so that the position of the ultrasound beam on the neck, when sensing arterial blood flow-velocities, can be translated onto a storage oscilloscope. By repeated passes of the transducer across the vessel lumen a 2 dimensional image of the carotid bifurcation is formed. As each image point is marked, the full spectrum of bloodvelocities corresponding to that position is continuously displayed on a second oscilloscope beside the image scope. Ultrasound images are compared with arteriograms and both continuous-wave and pulsed Doppler ultrasound imaging svstems are discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Using an in vitro system designed to measure arterial constriction, we have demonstrated the importance of platelet function in maintaining cerebral smooth muscle contraction after whole blood injection. We tested two agents, acetyl salicylic acid (ASA) and phthalazinol, both known to interfere with platelet function. In control tests normal rabbit and monkey blood produced a reliable and persistent arterial constriction. In experimental tests blood drawn from animals premedicated with ASA and phthalazinol failed to produce a persistent contraction. These results support the hypothesis that chemicals released during platelet aggregation may be important in persistent vasospasm.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID