ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

To clarify the causal relationship between spontaneous recanalization of the occluded cerebral artery and development of hemorrhagic infarction, 15 patients with internal carotid or middle cerebral arterial axis occlusion were submitted to consecutive lumbar punctures and follow-up cerebral angiography. Consequently, six of seven recanalized patients had sanguineous cerebrospinal fluid (CSF) on the second or third day after ictus, while only one of eight non-recanalized patients had bloody CSF. It was strongly suggested that recanalization might have an intimate relationship with the development of hemorrhagic infarction.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Regional cerebral blood flow (bicompartmental and stochastic method) was measured in a series of 20 patients with unilateral brain softening. Measurements were repeated during the administration of a vasodilator. A detrimental effect on the perfusion of the diseased area was observed in the majority of cases. It has been shown that the chances for a vasodilator to decrease the perfusion in the diseased area were greater when the angiogram showed obstruction of an intracranial artery.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

A 43-year-old man, who died five months after the onset of left-sided sensory deficit, had angiographical and pathological evidence of an angiitis confined largely to the distribution of the right middle cerebral artery. Histological examination identified this process to be intracranial noninfectious granulomatous angiitis. Although certain clinical and pathological features of this disorder overlap with other vasculitides which affect the central nervous system, the disease nevertheless retains sufficient individuality to warrant status as an entity, and should be considered in the differential diagnosis in adults with lesions which produce focal neurological deficits and signs of increased intracranial pressure. The definitive answer regarding an infectious etiology will come only from detailed culture studies of the affected vessels.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Electron and light microscopic studies were performed on rabbit brain to re-examine the structural changes of endothelial cells and perirascular glia following ischemia. Although swelling of perivascular glia occurred, earlier findings of extreme perivascular glial swelling and bleb formation leading to luminal collapse and plugging could not be confirmed. Ischemic brains, however, had a higher proportion of small-diameter capillaries than controls. It is felt that structural changes in ischemic capillary walls in themselves are not sufficient to explain failed cerebral reperfusion, or the no-reflow phenomenon.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Radionuclide cerebral blood flow (CBF) examinations of 48 patients with atherosclerosis, 18 with occlusion and 30 with stenosis of the internal carotid artery (ICA) were correlated with their respective cerebral angiograms. The following results were obtained. Flow was visually unilaterally diminished in 29 (60%) of 48 patients, including 14 (78%) with occlusion and IS (50%) with stenosis. Sixty-two percent of the subjects with severe stenoses and 46% of the patients with mild stenoses had a positive flow study. Diminished flow was evident in the neck in 80% of the patients, intracranially in 20%. Positive radionuclide angiograms always pointed to the side with occlusion or the greater degree of stenosis even though bilateral internal carotid disease was frequently found (54%). The data leading to the differentiation between major and minor ICA stenosis are not sufficient to justify any conclusion.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Cerebral hemispheric blood flow (HBF) and metabolism were measured before and after withdrawal of 20 to 30 ml of cerebrospinal fluid (CSF) over a 10-minute interval in eight patients with recent cerebral infarction and in four patients with Alzheimer's disease (AD). Immediately after CSF removal HBF decreased significantly in the AD group (−14%) but showed no significant change in the stroke group (−5%). There was rapid reduction in cerebral venous O2 content and some increase in cerebral venous Pco2 appearing within 60 seconds of CSF withdrawal, interpreted as a rapid reduction of cerebral blood flow (CBF) as judged by cerebral A-VO2 differences. The reduction in CBF was confirmed by the hydrogen clearance method. Reduction of CBF in response to lowering CSF pressure is presumably of neurogenic origin since it was rapid and occurred without changes in Paco2 or MABP. Furthermore, measurement of HBF demonstrated that cerebral metabolism remained constant after CSF removal. It is postulated that in AD, reduction of HBF following CSF withdrawal is mediated by a disordered neurogenic veno-arterial vasoconstriction reflex which is stimulated by rapid reduction in CSF pressure (CSFP). In patients with stroke, when cerebral perfusion pressure is increased by lowering CSFP, CBF is maintained constant most likely by a physiological cerebral veno-arterial vasoconstrictive reflex. Apparently, this vasoconstrictive reflex becomes excessive in Alzheimer's disease, possibly due to cerebral neurogenic imbalance.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

As shown previously, the electrical function of the brain is critically dependent on cerebral blood flow in the sense that reduction beyond an ischemic threshold of approximately 15 ml/100 gm per minute (approximately 35% of control) in the baboon leads to complete failure of the somatosensory evoked response. This study tests the hypothesis that electrical failure in ischemia may be directly associated with a massive release of intracellular K+ or with a critical degree of extracellular acidosis. By microelectrode techniques, measurements of blood flow, extracellular activity of K+ and H+ as well as evoked potential were made in the baboon neocortex. Reductions in blood flow were obtained by occlusion of the middle cerebral artery and depression beyond the ischemic threshold of electrical function achieved by a reduction of systemic blood pressure which, in the ischemic zones, changed local cerebral blood flow proportionally. Abolition of evoked response could not be explained by depolarization by release of intracellular K+, nor was it critically dependent on cortical pH. However, the massive release of intracellular K+ was by itself critically dependent on cortical blood flow and occurred at 18 > 6 > 2 ml/100 gm per minute (median with 5% confidence limits). Thus a dual threshold in ischemia for neuronal functions is described, the threshold for release of K+ being clearly lower than the threshold for complete electrical failure. Further, the findings support the concept of an ischemic penumbra during which the neurons remain structurally intact but functionally inactive. That neurons can survive for some time in this state of lethargy is evidenced by the observations that an increase in rCBF, if sufficient, can restore evoked potential and normalize extracellular K+ activity as well as pH.Abolition of evoked response could not be explained by depolarization by release of intracellular K+, nor was it critically dependent on cortical pH. However, the massive release of intracellular K+ was by itself critically dependent on cortical blood flow and occurred at 18 > 6 > 2 ml/100 gm per minute (median with 5% confidence limits). Thus a dual threshold in ischemia for neuronal functions is described, the threshold for release of K+ being clearly lower than the threshold for complete electrical failure. Further, the findings support the concept of an ischemic penumbra during which the neurons remain structurally intact but functionally inactive. That neurons can survive for some time in this state of lethargy is evidenced by the observations that an increase in rCBF, if sufficient, can restore evoked potential and normalize extracellular K+ activity as well as pH.

ISSN:0039-2499    

出版商:OVID    

年代:1977

数据来源: OVID