摘要:

The experiments in this report were designed to evaluate the effect of superficial temporalmiddle cerebral artery (STA-MCA) anastomosis on the course of middle cerebral artery (MCA) occlusion by emboli while avoiding a vessel clipping technique as well as the use of long-acting barbiturate anesthesia. Dogs were divided into 3 general groups: A) embolus placement 1 b following anastomosis; B) embolus placement 5 h prior to anastomosis; C) control group without anastomosis. Anastomosis prior to MCA occlusion has a favorable clinical effect and reduces the size of an infarction. Anastomosis 5 h after embolus placement is deleterious unless other therapeutic modalities can be shown to delay the course of infarction.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Cerebral arteries have an abundant supply of adrenergic nerve fibers which are believed to release vasoactive substances responsible for the induction of cerebral vasospasm. To assess the importance of adrenergic nerves in this phenomenon, high doses (600 μg/ml) of 6-hydroxydopamine (6-OHDA) were used to produce in vitro chemical sympathectomy in bovine middle cerebral artery. 6-OHDA reduced catecholamine fluorescence to undectable limits. H3-norepinephrine re-uptake was reduced to 1.5% of intact controls. Arterial norepinephrine content was reduced by 92%.Contractile responses to norepinephrine, serotonin, and fresh human whole blood were modestly reduced after denervation. This reduction was probably due to alpha receptor inactivation by 6-OHDA, because after protection of the alpha receptors with phentolamine the vessel response was the same as in untreated controls. Contractions in response to aged human whole blood were not affected by denervation. The results suggest that the endogenous release of catecholamines does not play a major role in the initiation or spread of bloodinduced vasospasm in large cerebral arteries.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Three hundred sixty-seven carotid endarterectomies were monitored using routine electroencephalographic (EEG) techniques. In 9.8%, changes in the EEG followed clamping of the internal carotid artery and could roughly be grouped into 6 patterns. The most common (47%) was rapid unilateral or bilateral attenuation of background anesthetic-induced fast EEG activity. Conclusions drawn from studies of the 9 patients who had immediate postoperative neurological deficits of varying degrees are presented as they illustrate monitoring techniques that are useful for early recognition of cerebral ischemia. Thirty-five patients were monitored with both routine and computerized techniques - the latter proved more useful than the former on all counts.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Evidence of cerebrovascular disease at autopsy was compared in 2 groups of men: 186 longtime residents of Hiroshima, Japan, and 253 men of Japanese ancestry long resident in Honolulu, Hawaii. They were 45 to 71 years-of-age at death. Atherosclerosis of the circle of Willis and its major branches, sclerosis of the intraparenchymal arteries and the frequency of cerebral hemorrhage and cerebral infarct were compared in the 2 populations. The Honolulu subjects had significantly more atherosclerosis of the circle of Willis, but less intraparenchymal artery sclerosis and less cerebral infarction. Cerebral hemorrhage was equally frequent in the 2 cities. It was concluded that cerebral infarction is more frequent in Japanese men in Hiroshima than Honolulu, and that men of Japanese ancestry in Honolulu are spared an appreciable risk of cerebral infarction through decreased frequency of intraparenchymal arterial sclerosis despite higher levels of atherosclerosis of large intracranial arteries.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

In an effort to evaluate the effectiveness of the Doppler Ophthalmic Test (DOT) following carotid endarterectomy, a large group of patients was examined both pre- and postoperatively with noninvasive techniques. The DOT, which has proven to be a useful non-invasive diagnostic test for the determination of significant carotid artery stenosis, was found to be persistently abnormal in 46% of patients with a preoperative positive test. This occurred in spite of the fact that operative arteriography, direct ultrasonic auscultation, and Doppler imaging studies were all within normal limits. It is suggested from this study that the Doppler Ophthalmic Test alone is not adequate to follow patients postoperatively, especially if an abnormal study persists following a satisfactory endarterectomy. Other non-invasive techniques, which employ direct ultrasonic imaging of the carotid flow, may be more accurate in determining vessel patency.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Local application of prostacydin (PGI2) to cerebral (pial) microvessels, inhibited the aggregation of platelets induced in the vessels by exposing them to a filtered mercury light source following intravenous sodium fluorescein. The inhibition was consistantly observed in venules rather than arterioles and was manifest by a lengthening of the time required for the noxious stimulus to produce an initial aggregate, and/or by a lengthening of the time required for enlarging aggregates to totally block the venule. The consistency of the inhibition diminished at doses below 100 μg/ml. Inhibition was observed whether or not alcohol was used as the vehicle for PGI2and whether or not the body temperature of the anesthetized mouse was permitted to fall.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Experiments were performed on 2 groups of baboons anesthetized with Sernylan. One group served as control and the other was premedicated with 5 mg/kg phenoxybenzamine (PBZ). A 2-step hypovolemic shock model was used followed by retransfusion of the shed blood. Cerebral blood flow was measured by the188Xe clearance method. Arterial and cerebral venous samples were taken and analyzed for blood gases as well as glucose and lactate content. The cerebral metabolic rates of oxygen, glucose, and lactate were calculated. In addition, the effect of CO2inhalation was studied before shock was induced. PBZ produced no effect on either CBF or the flow response to CO2prior to bleeding. PBZ pretreatment prevented the fall in cerebral blood flow and CMRO2produced by systemic hypotension due to bleeding. Lactic acid showed no evidence of change either in production or uptake by the brain during the experimental procedure. The cerebral metabolic pathway of glucose, however, seemed to be affected by PBZ both before and during shock.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

The influence of sympathetic nervous activity on cerebral circulation and cerebrovascular CO2reactivity was investigated through inhibition of dopamine /J-hydroxylase (DBH). A Po2electrode, a Pco2electrode and a plate-type thermocouple-flowmeter were placed on the pial surface of the cat brain. Cerebrocortical Po2, Pco2, cerebrocortical blood flow and arterial blood pressure were continuously recorded before, during and after intracarotid infusion of 10 mg/kg of fusaric acid, a potent DBH inhibitor. The effects of 5% CO2inhalation and hyperventilation were measured before and after the inhibition of DBH. Following the intracarotid infusion of fusaric acid, cerebrocortical Po2and cerebrocortical blood flow increased significantly. After the inhibition of DBH, the degree of the increase in cerebrocortical Po2during 5% CO2inhalation was enhanced while the degree of the decrease in cerebrocortical Po2during hyperventilation did not show any significant change. The cerebral vasodilatation caused by fusaric acid suggests that the sympathetic nervous system takes part in the resting tone of cerebral blood vessels. The increase in the cerebrovascular CO2reactivity produced by the inhibition of DBH suggests that the sympathetic nervous system modifies cerebrovascular CO2reactivity.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Thirty-nine thrombosed arterial segments of the branches of the circle of Willis were studied by a complete serial section technique. Twenty-two patients had been hypertensive and 8 had hypercholesterolemia before the onset of cerebral artery thrombosis. The histological characteristics of the thrombosed arterial segments were intramural hemorrhage in 28 segments, superficial edema of the fibrous cap of the atheroma or fibrous plaque in 4, rupture of the atheromatous plaque in 1, superficial accumulation of foam cells in the atheroma in 1 and an atheroma or fibrous plaque without any other changes in 5. They were many intramural small blood vessels in the atheroma or fibrous plaques of 22 segments with intramural hemorrhage. Fibrinoid degeneration of these small blood vessels was noted in 5. These findings suggested that intramural hemorrhage from the intramural small blood vessels was the major cause of cerebral artery thrombosis and that persistent hypertension not only promoted cerebral atherosclerosis but also induced hemorrhage from the intramural small blood vessels.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

A new model of internal carotid artery embolism was developed using autologous clot. The clot was prepared by incubating blood at room temperature for 2 hours to inactivate plasminogen activators and then refrigerating it at 4° C for 22 hours. The purpose of the experiment was to devise a model of the intravascular lesion and not of stroke itself. The dog was chosen as the experimental animal since it has a maxillocarotid artery which permits collateral flow beyond proximal internal carotid artery occlusions. A volume of clot measuring 0.25 to 030 cc was sufficient to occlude the artery for 48 hours in 80% of the animals without causing major strokes. We have used this model to study clot radiolabeling and suggest it may also have application for evaluating thrombolytic drugs.

ISSN:0039-2499    

出版商:OVID    

年代:1979

数据来源: OVID