摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

In a group of 48 patients with completed stroke, 8 patients had viable collaterally perfused brain tissue which was accessible for rCBF recordings with a two dimensional technique. All 8 had deep subcortical infarcts on CT-scan, and angiographic occlusion of the arteries normally supplying the infarcted territory. The brain tissue overlying the deep infarcts appeared normal on CT-scan and was supplied by collateral circulation. rCBF was measured in all within 72 hours after the stroke. The intra-carotid Xe-133 injection method and a 254 multidetector camera were used to study rCBF. Relatively ischemic low flow areas were a constant finding in the collaterally perfused tissue. In 6 of the patients, the collaterally perfused part of the brain had low flow values comparable to those of an “ischemic penumbra” (viable, but functionally depressed brain tissue due to inadequate perfusion). Autoregulation was impaired in all of the collaterally perfused areas while the CO2-response always was preserved. Steal phenomena were not seen. In the surrounding brain tissue, autoregulation was normal in 5 patients and impaired in 3 while the CO2-response seemed to be normal. The results confirm the experimental finding of an ischemic penumbra associated with acute cerebral infarcts and suggest that early restoration of the blood flow in acute stroke patients might improve recovery and prognosis in selected patients.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

To examine long-term trends in subarachnoid hemorrhage (SAH) mortality and morbidity, an analysis of routinely available information is presented for the 20 year period from 1959. To document the current incidence and case fatality of SAH, the results of a large scale community-based study in the Auckland region are presented. SAH mortality rates for both men and women, especially women, have declined since the mid-1970's. The decline appears to be real, and is most striking in the 45−64 year age groups. A corresponding decline in discharge rates from hospital has also occurred in these age groups. In contrast, cases fatality rates have remained stable at about 42% for the 20 year period under review. The community-based study identified 92 cases in a total population of 829,464 in a twelve month period. The age standardised incidence rates were 13.4 and 15.8 per 100,000 for men and women respectively. In the age group 25–35 years, the incidence rate was particularly high at 8.5/100,000. Case fatality at 28 days was 52%. A decline in incidence appears the most likely explanation for the overall decline in national mortality.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

This study was performed to elucidate mechanisms responsible for the contraction of isolated canine cerebral arteries induced by uridine 5′-triphosphate (UTP) and to ascertain whether UTP given intracisternally causes cerebral arterial constriction. The latter was proven arteriographically to be the case. In vitro, UTP (10(−4)M) and UDP were similar in potency, produced sustained contractions, and were more effective than other pyrimidine nucleotides or uridine. Unlike serotonin (5-HT), UTP was not antagonized by cinanserin and failed to cause constriction of mesenteric arteries. Adenosine similarly antagonized 5-HT and UTP. The Ca2+ antagonist nimodipine abolished contractions caused by high K+ but only incompletely antagonized 5-HT or UTP. On the other hand, procedures that hyperpolarize the cell membrane (low K+ followed by K+) abolished tonic contractions induced by UTP. Hyperpolarization prior to UTP (with or without nimodipine) did not, however, prevent the occurrence of a phasic contraction. Papaverine or lanthanum antagonized this phasic response. It was concluded that UTP selectively affects cerebral arteries, may initiate contraction by releasing membrane bound Ca2+, depolarizes the cell membrane to open receptor operated and potential sensitive calcium channels, but does not inhibit the electrogenic Na-pump nor specifically antagonize the vasodilator adenosine.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The present technique was developed to overcome some of the disadvantages of measuring cerebral blood flow by radionuclide methods, such as poor localization of flow values and errors that result if the brain is pathological and local partition coefficients are altered. Serial CT scanning in humans was carried out during and after inhalation of 50 to 70% non-radioactive xenon. This diffusible gas with high atomic number enhanced gray matter first by 19 +/− 4 Hounsfield Units (HU) and later white matter by 24 +/− 4 HU. The regionality of flow values were cursored on CT pictures with a high spatial resolution of 4 × 4 mm (64 pixels) or 0.16cm2 × 0.5cm. In seven normal subjects, blood flow in gray matter was 82 +/− 11 ml/100gm/min and that in white matter 24 +/− 5ml/100gm/min. The partition coefficient (lambda), which is not obtainable in vivo by radionuclide scanning, was 0.9 +/− 0.1 for normal gray matter, 1.4 +/− 0.2 for normal white matter. Reduced flow, 13% in gray matter and 46% in white matter, was found in a large infarct secondary to complete occlusion of middle cerebral artery. In edematous tissue, blood flow was not significantly impaired in gray matter but was reduced to 29 to 54% in white matter. Local lambda values were reduced to 0.6-0.9 in edematous tissue, and 0.3-0.7 in infarction. This method appears to have several advantages over conventional isotope methods of measuring cerebral blood flow and provides useful clinical and research information.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

In order to understand the mechanism of clinical worsening in patients with cerebral infarction, attention was focused on the changes in cerebral angiograms obtained repeatedly before and after neurological deterioration. Among 212 stroke patients with minor neurological deficits, incomplete hemiparesis progressed to complete hemiplegia in 15 patients several days after the beginning of symptoms. On admission, 3 had internal carotid artery occlusion, 2 had stenosis of the internal carotid artery, 5 had occlusion of the middle cerebral arterial trunk, 2 had occlusion of the middle cerebral arterial branch, and 3 had no angiographically visible occlusion. The changes between the first and the second angiograms were of different varieties: another recurrent occlusion, progression of occlusion, new occlusion in the cerebral arteries opacified through the collateral pathway, recanalization of the initially occluded artery, and no change. Such different patterns of pathophysiological events show that the mechanism of neurological worsening in infarcted patients is not uniform. Based on the results from the present study, several problems which arose during the investigation and the somewhat vague definition of “progressing stroke” currently in use are discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Platelet aggregation in the post-acute phase of 48 patients with cerebral thrombosis was measured to see if any specific type of cerebral infarction is associated with enhanced platelet aggregation. All patients were examined with cerebral angiography and computed tomography (CT). Stenotic lesions in major cranial arteries were analyzed by measuring the apparent diameter. Severe stenosis was defined as 75 per cent constriction or more. Enhanced aggregation of platelets (secondary aggregation at 1 microM ADP or less) was present in 5 of 25 patients (20%) who had severe vessel stenosis or occlusion. CT examination frequently revealed both cortical and deep involvement. On the other hand, 13 of 23 patients (57%) with less stenotic lesions showed enhanced aggregation and that was statistically significant (p less than 0.05). Many patients of this group had persistent hypertension and small deep infarctions. Platelet aggregation was also measured in 20 hypertensive control subjects without stroke. Four of them (20%) showed enhanced aggregation. These findings suggest that a combination of enhanced platelet aggregation and hypertension increases the risk of small deep infarctions accompanied by mild stenotic changes of the major cranial arteries.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The male Sprague-Dawley rat was successfully used to produce increases in arterial blood pressure and electrocardiographic abnormalities similar to those seen in patients after a subarachnoid hemorrhage. The model employs a less expensive, easily available laboratory animal than other existing models. Whole heparinized blood is introduced in the area of the circle of Willis to simulate a subarachnoid hemorrhage. This model ensures a constant body-blood volume and minimizes damage to brain tissue as no blood vessel has to be punctured. The volume of blood required to produce bradycardia and other electrocardiographic abnormalities can be controlled and calculated for each animal. The model produced a sudden onset and progression of cardiovascular symptoms. Blood apparently is specific for producing electrocardiographic abnormalities as compared to 0.9% saline, Dextran 40 and Gentran 75 when introduced in the area of the circle of Willis. This specificity was not maintained when blood and saline were introduced into the cisterna magna as electrocardiographic abnormalities were observed with both agents.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Two young adults with lupus anticoagulant had multiple attacks of cerebrovascular ischemia in different arterial territories. Cerebral angiography was normal. One patient had a new episode during anticoagulant therapy, but has remained asymptomatic on antiplatelet treatment. In the other, further events occurred during treatment with platelet-inhibiting drugs, but there have been no recurrences with adequate anticoagulant therapy. Lupus anticoagulants are possible causes of otherwise unexplained thromboembolic events. Due to the variable mode of action of these immunoglobulins, platelet-inhibiting drugs may in some cases be considered as a prophylactic alternative to anticoagulant treatment.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Concentrations of cyclic AMP and cyclic GMP in arterial and internal jugular venous (IJV) blood were determined at the resting wakeful state in thirty surgical patients without neurological deficits. The levels of cyclic AMP in artery and IJV were 32.1 +/− 3.0 and 40.0 +/− 4.1 pmol/ml (means +/− standard errors), respectively, while those of cyclic GMP in artery and IJV were 12.2 +/− 2.7 and 14.4 +/− 3.0 pmol/ml, respectively. Concentrations of both cyclic nucleotides in IJV were significantly higher (P less than 0.001) than those in artery. IJV-arterial differences for cAMP and cGMP were 7.9 +/− 1.7 and 2.1 +/− 0.5 pmol/ml, respectively. The results indicate that both cyclic nucleotides are constantly produced and released from the normal human brain.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID