ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Regional cerebral blood flow was studied by means of the133Xe inhalation method hi 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal regions hi the previously diagnosed group, and this was attributed to pathological changes in the district served by the middle cerebral artery. Regional temporal lobe impairment was also noted in the newly diagnosed and treated subjects. A significant correlation was found between regional cerebral blood flow and mean arterial blood pressure. (Stroke1987; 18:13–20)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Seventeen chronic cerebral Infarcts were investigated by a highly sensitive, dedicated brain single photon emission computerized tomography system using123I—isopropyl iodoamphetamine (IMP) and133Xe. IMP uptake was measured 10 minutes, 2 hours, and 5 hours after injection, and regional cerebral blood flow was measured with133Xe. In 4 cases a positron emission tomography system was used to measure the rCBF and the regional metabolic rate of oxygen with C15O2and15O2. The results obtained allowed us to identify 2 abnormal zones. One, the “central area,” was characterized by a severe decrease in IMP uptake and rCBF averaging 34% and 46% respectively and by a hypodense image on the x—ray computerized tomography scan. The second, the periinfarct or “peripheral area” was characterized by a moderate decrease in IMP uptake and regional cerebral blood flow averaging 13 and 19% respectively; this area extended around the central area and had a normal density on computerized tomography scan. The IMP hypofixation of the peripheral area observed at the 10th minute tended to disappear at the 5th hour. The volume of this area was often found to be quite large, covering more than 30% of a hemisphere whereas the central area did not exceed 25%. Volume appeared to be correlated with the neurological status of the patient. The nature of the peripheral area is not established with certainty. It may be caused by deafferentation of areas not directly affected by the ischemlc insult and/or selective ischemic neuronal loss. The results stress the important role played by the peripheral area, which may be useful in establishing the prognosis and evaluating the efficacy of therapy in individual stroke cases. (Stroke1987;18:21–29)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Submerged hippocampal slices were exposed to 30 minutes of moderate or mild hypoxia at 29°C and then reoxygenated. Synaptic transmission was lost at the same rate in response to either grade of hypoxia, but recovery was faster following mild hypoxia. Hyperexcitability of synaptic transmission was a lasting feature following moderate hypoxia, but it was transient following mild hypoxia; after mild hypoxia the strength of synaptic transmission eventually returned to normal. Extracellular calcium did not change during moderate hypoxia. The extracellular pH of slices was always more acid than the bath; pH decreased further in response to both moderate and mild hypoxia. Extracellular potassium increased more during moderate than during mild hypoxia, and a period of rapid potassium uptake was also more pronounced following moderate hypoxia. Extracellular DC potential demonstrated a small positive shift during hypoxia, more so during mild hypoxia. These experiments suggest that synaptic function can be reversibly suppressed in mildly hypoxic brain tissue without severe depolarization of neurons; in addition, the degree and duration of posthypoxic hyperexcitability are correlated with the degree of hypoxia and the magnitude of the release of K+ from cells into their environment. (Stroke1987;18:30–37)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

We investigated the seasonal pattern of stroke using the Lehigh Valley Stroke Register. This register includes all patients hospitalized with stroke or transient ischemk attack (TIA) from among the 600,000 Lehigh Valley residents. Meterological data were obtained from the National Oceanic and Atmospheric Administration. The study, which uses 18 months of data, included 1,944 cases. Using single harmonic regression analysis, the seasonal pattern of TIA and infarction, but not hemorrhage, fit a sine—cosine wavefunction with a 12‐month period (R2= 41% and 36%, respectively). For infarction, the strongest seasonal pattern was exhibited for women of all ages and for both sexes in the age groups 65–74 and 75–84, but only the sine component was significant. The peak months for TIA were June—August, while the peak months for infarcts were February—April. Correlations between ambient temperature and each type of stroke were computed. A significant positive correlation for TIA was found (r = 0.57, p = 0.01). After adjusting for a 2‐month lag between the low for infarction and the peak for temperature, a significant negative correlation was found (r = −0.64, p = 0.01). No significant correlation was found for hemorrhage. Possible reasons for the opposite relations of TLA and infarct are discussed. (Stroke1987; 18:38–42)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

To evaluate the influence of age on carotid atheroma we reviewed the angiographtc findings in 120 patients with reversible ischemic attacks. The prevalence and severity of atherosclerotic lesions increased significantly with age, and this difference persisted after adjusting for hypertension. These results may at least partly explain the poor long term prognosis for elderly subjects with reversible ischemic attacks, and underscore the importance of taking age into account when relating clinical and angiographic findings in patients with cerebrovascular ischemia. (Stroke1987;18:43–45)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Regional cerebral blood flow, blood volume, fractional oxygen extraction, and oxygen consumption were measured by positron emission tomography in 4 stroke patients prior to and 6 months following omental transposition surgery. Preoperatively, 3 patients showed the typical picture of established infarction with a matched reduction in flow and oxygen metabolism and a normal oxygen extraction fraction in the symptomatic hemisphere. One patient showed a chronically impaired perfusion reserve with a proportionally greater reduction in flow than oxygen metabolism and a compensatory rise in oxygen extraction ratio. No change in the physiological parameters was demonstrated in the postoperative studies. (Stroke1987; 18:46–51)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

The presence of hyperglycemia prior to stroke or cardiac arrest can increase neuronal damage caused by brain ischemia. Acute hyperglycemia shows this effect in animal models of stroke. However, chronic hyperglycemia and chronic hyperglycemia with additional acute elevation of blood glucose are more common premorbid states for stroke patients. The effect of chronic hyperglycemia on regional cerebral blood flow (rCBF) is unclear but blood flow changes may play a role in this ischemic cell damage. We measured rCBF in awake restrained rats that had chronic hyperglycemia induced by treatment with streptozotocin. This was compared to that measured in rats made acutely hypergh/cemic by injecting glucose into the peritoneal space. rCBF was measured in 17 brain regions using [14C]iodoantipyrine. During chronic hyperglycemia, when plasma glucose was 29 μ.m/ml, rCBF was decreased and a regional distribution of this effect was noted; 9 hindbrain regions showed a mean flow decrease of 14% while forebraln regions demonstrated less flow reduction. Acute elevation of plasma glucose during normoglycemia or superimposed on chronic hyperglycemia produced flow reductions of 7% for each 10 /μm/mJ increment in plasma glucose up to 60 /μm/ml. Both chronic and acute hyperglycemia are associated with decreased rCBF and the mechanism for this effect does not appear to adapt to chronic hyperglycemia. (Stroke1987; 18:52–58)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID

摘要:

Eighteen patients with recent ischemic stroke were compared with an equal number of matched controls. Standardized suspensions of red cells as well as of red and white cells were filtered in a new filtration apparatus capable of discriminating between cell deformability and filter occlusion. Results show that red cell deformability, although slightly lower than in controls, is not significantly altered in stroke patients. Filter occlusion, however, was significantly higher in patients when red and white cell suspensions were filtered, but not when red cell suspensions were used, suggesting that white cell filterability is impaired after stroke, which could be due to decreased deformability and/or increased adhesiveness of leukocytes. Slowed white cell passage may also occur in the living microcirculation and may present an obstacle to nutritive flow in exchange vessels, possibly contributing to local ischemia and tissue necrosis after stroke. (Stroke1987;18:59–62)

ISSN:0039-2499    

出版商:OVID    

年代:1987

数据来源: OVID