摘要:

In specimens from the superficial temporal artery (STA) and middle cerebral artery (MCA), obtained during STA-MCA anastomosis, green fluorescent varicose fibers of sympathetic nerves were clearly visible with both formaldehyde-glutaraldehyde and sucrose-potassium phosphate-glyoxylic acid wet-histofluorescent techniques. These fibers were fairly thick, were densely packed and had a meshwork-like arrangement. Fluorescent terminals were seen both in the adventitia and in the outer muscular layer of the media in both STA and MCA specimens. They were more often observed in patients with prominent atherosclerosis in these vessels. The present study suggests the possible role of sympathetic nerve terminals in the development of vasospasm and occlusive lesions in cerebral vessels. It may also help to explain the marked constriction and transient occlusion following a STA-MCA bypass procedure.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Local cerebral blood flow (1CBF) was measured simultaneously in ten cats with (1) a large surface thermal diffusion probe resting on the cortex and (2) hydrogen clearance curves from implanted electrodes surrounding the thermal probe. A close correlation was found between 1CBF values obtained by the two methods. Since hydrogen clearance is accepted as quantitative, the data suggest that the thermal diffusion technique is a reliably quantitative means of measuring local cerebral blood flow.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The geometry of arterial bifurcations appears to play a significant role in the development of vascular disease. We have investigated the changes in bifurcation geometry with changes in distending pressure over the range 0.0 to 190.0 mm Hg. Five cerebral arterial bifurcations from human subjects were studied. The investigation focussed on the shape and on changes in the shape of the leading edge of the flow divider (internal apical curve). The curve outline at each transmural pressure increment (each 10.0 mm Hg) was photographed and digitized. The curves were plotted serially on an expanded scale. Visual comparison of the curves indicated flattening in the central region and broadening of the shoulders of the curves with increasing transmural pressure. Regression analysis using second order polynomials was used to obtain coefficients for equations defining short, overlapping segments of each curve. Twenty-four coordinates were used for each successive regression. Each curve was characterized by 85 to 100 digitized coordinates. The regression equations for each curve were used to calculate the curvature parameter, K, and the radius of curvature, R. Three of the five bifurcations demonstrated a negative correlation of K with increasing transmural pressure (p less than .001). This result supports the visual observation that the internal apical curve flattens with increasing transmural pressure. Flattening of the internal apical curve together with thinning of the arterial wall with increasing transmural pressure would contribute to a stress concentration at the apex of a cerebral bifurcation. This stress concentration would be more pronounced in the presence of a medial gap at the apex of the bifurcation. It is on or near this region of stress concentration that aneurysms develop.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Cerebral blood flow and clinical parameters were studied in 30 stroke patients at 15th, 30th, 60th, 90th days after the cerebral insult (Xenon 133 inhalation method). The clinical improvement was not accompanied by a progressive normalization of the CBF at rest. No relationship was found between the clinical data and the CBF values; either on the affected hemisphere or on the contralateral one. It is concluded that measurement of the CBF at rest has no predictive value as regards further clinical evolution.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

We tested the reproducibility of consecutive measurements of regional cerebral blood flow (rCBF) made in 13 areas of each hemisphere in patients with cerebrovascular diseases by the atraumatic 133Xe intravenous injection method. The data were analysed by a two-compartment model similar to that used in the Obrist inhalation method. Four parameters derived from the model were tested: Fg (flow of the fast-clearing compartment), FF and W (respectively fractional flow and relative tissue weight of the same compartment), ISI (initial slope index as defined by Risberg et al.). No significant variation was found in these four parameters between two consecutive rest measurements for all the areas studied and whatever the time interval between the measurements. The variances of the differences of Fg and ISI between the two measurements were found to be similar to those found in normal healthy subjects. The variances of FF and, consequently, W were greater than the values determined in healthy volunteers. An attempt to improve the quality of the results, by correcting them for the effects of PaCO2 changes between the measurements, resulted on the contrary in a general increase of the variances of the differences, showing the inadequacy of the correction coefficients used for healthy subjects at least for a proportion of the patients with cerebrovascular diseases. Sensitivity, tested by activation (hand work), shows a positive answer for FG but no significant change in ISI in any area. These findings demonstrate that in cases of cerebrovascular diseases the raw data (uncorrected for the changes in PaCO2) are the most reliable data but the meaning of the values found for FF and W must be regarded with caution since they may be affected by the “slippage” phenomenon. It is suggested that the ISI should only be used when there is evidence of a failure of the compartmental model, but only as a rough estimation of the flow level because of its lack of sensitivity.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The purpose of this study was to determine resting and maximal superior cervical sympathetic nerve activity in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) at five and ten weeks of age as hypertension was developing. Basal cervical sympathetic nerve activity (SNA) of five week SHR was 58 +/− 3 muv which was significantly elevated over age-matched WKY (SNA = 30 +/− 4 muv, p less than 0.001) and ten week SHR (SNA = 30 +/− 4 muv, p less than 0.001) as well as ten week WKY (SNA = 24 +/− 4 muv, p less than 0.001). Thus, during basal conditions five week SHR nerve traffic was approximately two times that found in age-matched WKY as well as in ten week SHR and WKY. The peak sympathetic nerve activity in response to rapid hemorrhage in five week SHR (215 +/− 16 muv) was significantly elevated over the maximal response of WKY (140 +/− 23 muv) (p less than 0.02). Ten week SHR also reached a maximal sympathetic nerve activity (187 +/− 28 muv) that was significantly elevated over WKY (100 +/− 15 muv) (p less than 0.02). Thus, both five and ten week SHR had a greater capacity for elevated nerve activity following rapid hemorrhage than age-matched WKY. The elevation in resting cervical sympathetic activity in five week SHR, and the elevated capacity for sympathetic neural response in both five as well as ten week SHR, are consistent with a central nervous system abnormality in SHR that could relate to the previously described protective influence of sympathetic nerves on SHR cerebral blood vessels as hypertension is developing.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The Persantine Aspirin Trial is a double-blind multi-centered cooperative study focusing primarily on the question of whether the administration of the combination of aspirin and dipyridamole (Persantine) will result in a greater reduction of cerebral or retinal infarction or death than the administration of aspirin alone. Fifteen centers in the United States and Canada are participating. More than 750 individuals with a history of recent carotid territory transient ischemic attacks (TIAs) have been admitted over the past four years and randomly allocated to either aspirin (325 mg) plus placebo four times daily or aspirin (325 mg) plus Persantine (75 mg) four times daily. It is anticipated that the study will continue through 1983. Analysis and publication of results are planned for 1984.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

One hundred cases of Moyamoya disease were encountered between 1961 and 1980. This report describes the clinical characteristics and emphasizes the angiographic findings and clinical correlation in this disease. Reasons for the differences in clinical and radiological presentation in children versus adults are proposed and a possible pathophysiological mechanism is outlined. Treatment with perivascular sympathectomy and superior cervical ganglionectomy may be useful but more investigation needs to be carried out into the pathogenesis of the disease before more definitive therapy is realized.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID