ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

To test the effectiveness of betahistine HCl in reducing the frequency of transient ischemic attacks (TIAs) caused by vertebral-basilar artery insufficiency, we randomly assigned 26 patients with a typical history of the condition to a placebo-drug or a drug-placebo sequence, each sequence lasting two months. During the study, the frequency of TIAs did not differ significantly between the placebo and the drug groups. Subjective responses indicated some value for betahistine as a palliative agent.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Regional cerebral blood flow (CBF) was measured (intra-arterial injections of133Xe) and electroencephalograms (EEG) were recorded periodically before, for two hours during, and for one and one-fourth hours after middle cerebral artery (MCA) occlusion in 20 squirrel monkeys (Saimiri sciureus). A CBF-Paco2response curve for these animals under barbiturate anesthesia was created from CBF values prior to MCA occlusion and during the time a steady state was being achieved. The animals were subdivided into four groups (five monkeys in each) on the basis of Paco2values: 20, 36, 40, and 60 mm Hg. CBF values from this study were compared to previous results obtained with35Kr. The phenomenon of “look through” and the importance of recognizing this artifact and its significance in analyzing CBF results in areas of focal ischemia are discussed. The present results were correlated with cerebral ATP and lactate concentrations in ischemic regions determined in previous studies using this preparation at these Paco2values and at comparable time intervals before, during, and after MCA occlusion. The EEG appears to reflect the state of ischemic brain accurately. However, CBF measured by the133Xe method can be misleading in regard to the true degree of ischemia resulting from occlusion of an intracranial vessel and cannot be relied on to demonstrate accurately “steal” or “reverse steal” due to changes in Paco2.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

In 20 patients with acute major cerebral arterial occlusion, follow-up angiograms were obtained to inspect the occluded artery. These angiograms were compared with brain scans in the fourth week after the stroke. The angiograms revealed that frequent recanalization of the occluded arteries occurred within a week after the onset. On the other hand, brain scans showed the increased uptake of radioisotopes even in the patients with angiographically demonstrated arterial recanalization.The present study clarified that positive scans could be obtained in the patients with and without recanalization, and emphasized the diagnostic value of brain scans in the subacute or chronic stage of cerebral infarction, especially in patients with no arterial occlusion appearing on the angiograms.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The frequency of abnormal brain scans in patients with cerebral vascular disease admitted to a stroke intensive care unit has been evaluated in relation to diagnosis, time after onset of symptoms, effect of delayed imaging and the degree of clinical neurological recovery. In patients with completed thromboembolic infarction, 33% had abnormal scans including 39% of those with hemispheric lesions and 14% with posterior fossa lesions. Completed hemorrhagic infarction occurred in seven patients, and three (43%) had abnormal brain scans. Of 14 patients with either transient ischemic attacks or reversible ischemic neurological deficit, two (14%) had abnormal scans. Twenty-seven percent of brain scans in patients with completed thromboembolic infarction were abnormal in the first two days after infarction, a higher frequency than previously reported. Delayed images confirmed the initial interpretation that the scan was either normal or abnormal in 71% of the cases while in 10% of the cases only the delayed views were abnormal. The frequency of abnormal scans was significantly greater in patients who died or had a large neurological deficit at discharge than in patients with lesser residual deficit.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Repeated measurements of regional cerebral blood flow (rCBF) were made by the short (ten minutes)133Xenon inhalation technique and bicompartmental analysis in 11 patients with cerebrovascular disorders, mainly acute cerebral infarction. rCBF was measured 3 to 11 times during one to two weeks. The blood flow of the fast compartment (f1) was calculated as well as the relative weight of this compartment (w1, assumed to correspond to gray matter). In addition a new flow index, the Initial Slope Index (ISI) modified for the inhalation technique, was used. This index of predominantly gray matter flow was calculated from a one-minute epoch of the early part of the clearance curve corrected for recirculation. In three of the patients the f1and ISI varied in parallel and the w1showed generally only minor variations from one measurement to the other. However, in the other eight patients fluctuation of the w1and f1values were seen which often showed no meaningful relation to the clinical course. The observed w1changes indicated that some tissues (slowly perfused gray matter and/or rapidly perfused white extracerebral tissues) fluctuate between the fast and the slow compartment. In such cases the f1values obtained cannot be used for comparison between measurements, since they represent flow rates of varying tissues and do not always represent a true gray matter blood flow. In these patients the ISI, which is independent of such weight changes, showed moderate and clinically likely variations.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

An initial slope index of total cerebral blood flow, measured by the hydrogen clearance technique, shows a high correlation with flows calculated by bicompartmental analysis. In 247 flow measurements done on 41 rhesus monkeys, a linear regression analysis between these two methods of calculating flow shows a correlation coefficient of 0.928 with a standard error aboutyvalues of ± 7.63. The initial slope index is not only faster but does not require that a steady state be maintained for ten minutes.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Hindbrain transient ischemic attacks (TIAs) culminating in posterior circulation stroke are described in five children. Atlanto-axial subluxation and angiographical documentation of C1 to C2 level arterial pathology are documented in one patient. Four additional patients with nearly identical clinical presentations, posterior fossa TIAs, stroke and basilar angiographical pathology are reviewed. A mechanical traumatic etiology is suggested.Unexplained transient repeated brain stem and/or cerebellar symptomatology may be due to extracranial vertebral artery stenosis or occlusion by atlanto-axial instability. After appropriate documentation, stabilization may prevent further TIAs or strokes.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Regional cerebral blood flow (rCBF) measurements were performed over the contralateral hemisphere by the133Xe intracarotid injection method in 20 patients with acute cerebral infarction in the territory of the internal carotid artery. The rCBF was found to be reduced, sometimes remarkably, in all of the patients. The mean reduction was 30% to 36% from the lowest normal value for the mean age of these patients. In the younger age group (40 to 59) the reduction was greater, 40% to 47% from the lowest normal value for this age.The rCBF depression was not related to cerebral dominance, previous hypertension or arterial Pco2levels. It occurred in both patients who were fully alert and those with disturbances of consciousness, although it tended to be more diminished in the latter.It can be assumed that the flow reduction in the nonaffected hemisphere is part of a general phenomenon affecting the entire brain and caused by globally reduced cerebral metabolism.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

An uncommon type of stroke in children is presented. An intracranial arteriovenous malformation in a 13-year-old boy spontaneously occluded about 22 months after surgical intervention. Precipitating factors, such as bacterial infections, could not be demonstrated in this patient, who had been attending school since the time of the craniotomy. The histological features of venous encephalomalacia in the galenic territory are contrasted with hemorrhagic encephalomalacia as seen after arterial occlusions: in the former, hemorrhages are more widespread and edema is more pronounced.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID