摘要:

Intraoperative measurement of regional cerebral blood flow (rCBF) by the133Xe intracarotid injection technique was performed in 17 patients operated on for stenosis of the internal carotid artery. Mean rCBF decreased from 51 ml/100 gm × minute before endarterectomy to 30 ml/100 gm × minute when the internal carotid artery was clamped, a reduction of 41%. Postoperative aggravation of neurological deficits was observed in five patients in whom rCBF was at or below 30 ml/100 gm × minute during the period of carotid clamping, indicating a critical lower limit of rCBF of this magnitude. Flow reduction below this limit was tolerated only if the occlusion time was short. A critical time/flow relation is suggested.Distal internal carotid artery blood pressure during clamping (measured in eight cases) was poorly correlated to rCBF (r = 0.62, 0.1 > P > 0.05).

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The records of the Mayo Clinic have been used as the primary basis for the study of stroke in the population of Rochester, Minnesota, from 1945 through 1954. The incidence rate for first stroke of all types was 1947/100,000/year. The rates increased with age, and at age 65 to 74 years, about 1% of the population was affected annually. No significant differences were noted between men and women. The rate for cerebral thrombosis was 146/l00,000/year for all ages. Cerebral hemorrhage represented less than 10% of all strokes and occurred in less than 15% of those who died; this is contrary to what is published in theU.S. Mortality Statistics. The prevalence rate was 547/100,000 on January 1, 1955. Twenty-one percent of these persons who had previously had a stroke were functioning with no incapacity on the date of prevalence determination and only 3% were bedridden. Death certificates were reviewed for all those who died after a stroke. Among those who died within a month after a stroke, some type of stroke was noted as the underlying or an associated cause of death in 91%. However, among those who died more than a month after a stroke, only 54% had such a diagnosis recorded. Probability of surviving after each type of stroke was determined and compared with survival in a normal population. The curve showing probability of surviving from cerebral thrombosis diverges throughout its course from that of the expected survival but diverges more sharply in the first several months. Among those patients with stroke who died, 41% died of causes related to the acute stroke and 10% died of a subsequent stroke. Heart disease was the cause of nearly twice as many deaths as was a subsequent stroke among those who survived the initial stroke. Autopsies were performed on approximately 50% of those persons who died following a stroke, and information from these studies confirmed the high degree of accuracy of the clinical appraisals.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Rabbits on a high-cholesterol diet deposit more lipid in the iris of the sympathectomized eye.Histologically, the lipid deposits are composed of sudanophilic staining droplets localized both in smooth muscle cell cytoplasm of the iris dilator muscle and in larger oval cells. Possible metabolic and vascular mechanisms are noted which may underlie these findings. Potential clinical implications of these findings are cited.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Left atrial myxoma should be considered seriously in patients with unexplained cerebral dysfunction, particularly those in whom there are multiple recurrent cerebral vascular episodes, despite the absence of suggestive heart findings. Substantiating this observation are two such illustrative cases with embolic disease leading to neurological involvement who otherwise lacked cardiac symptomatology and did not exhibit auscultatory, roentgenological or electrocardiographical evidence of heart disease. The first patient died without antemortem recognition of the tumor and, in the second, the myxoma was removed after eventual identification by cardiac angiography and histological examination of embolic material. Thus, it is recommended that left atrial myxoma be definitely sought by heart catheterization with contrast study as a potentially curable cause of chronic nervous system disease with transient episodes of vascular insufficiency even in patients without cardiac manifestations.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Localized osteoporosis in 25 long-term stroke patients was evaluated by means of measuring the combined cortical thickness in the humerus, radius and third metacarpal bones of both involved and noninvolved upper extremities. The combined cortical thickness was found to be consistently smaller on the involved side. Since the factors of weight bearing and calcium homeostasis were eliminated or controlled in this study, the authors were able to focus on the role of muscle pull as manifested by voluntary muscle function and spasticity in relation to the degree of cortical thinning. A smaller degree of cortical thinning was associated with better voluntary muscle function, but the relationship of spasticity to preservation of cortical thickness was not clear cut. The applicability of these techniques to the study of factors affecting localized osteoporosis is discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Data collected by record linkage are used as a basis for an analysis of the burden of cerebrovascular diseases in a population of 340,000 in central England. Comparison with studies which use other methods in the United States and England indicate that for all Cerebrovascular diseases together, and for subarachnoid hemorrhage, the assumptions underlying the analysis may have reflected the overall incidence of and survival from serious disease in Oxford reasonably accurately, but this may not be true for two individual rubrics, cerebral hemorrhage and infarction. Criticisms made of this conclusion in the recent literature are discussed. The system in its present state does not permit the study of transient ischemic attacks. Data shown here and elsewhere indicate that subarachnoid hemorrhage is the most reliable of the stroke diagnoses, and the Oxford data show reasonable consistency with others gathered elsewhere using other methods. It would appear that there are considerable age-specific and sex-specific differences for subarachnoid hemorrhage in terms of incidence and survival. Attention is drawn to the extent to which cerebrovascular disease occurs in people under age 65 years.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

The clinical impression that severe hyperreflexia is not consistently associated with severe spasticity in hemiplegia or hemiparesis due to vascular pathology was tested by objective measurement in 11 patients. The intensity of tendon reflex responses of the triceps and biceps brachii muscles was measured as the reflex sensitivity ratio (evoked twitch tension/stimulating hammer force). The degree of spasticity was measured as the threshold rate of elbow flexion or extension above which a myotatic response was elicited, determined by both a sudden increase in passive resistance and a burst of antagonist electromyographical activity.Rate thresholds were rank ordered for flexion data and for extension data with their corresponding reflex sensitivity ratios. Numerous individual discrepancies stood out. Correlation coefficients between rate thresholds and reflex sensitivities determined at two elbow angles were −0.52 and −0.35 during extension, and −0.47 and 0.03 during flexion.Differences in rate of stretch, differences in the sensory structures stimulated, and differences in the distortion of the organization of motor control may account for the difference in responses to the two tests.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

To determine the effects of nicotine HCl on the cerebral circulation of the cat, without the complicating actions of the drug at other sites in the body, the drug was perfused at concentrations of 1, 10 and 100 μg/ml through a vascularly isolated, perfused in situ cat brain preparation. Cats having selective section of cranial nerves 9, 10, 11 and 12 and the cervical sympathetic trunks comprised various experimental groups. Nicotine was also perfused through an isolated, denervated hindlimb of the same cat for comparative purposes. Nicotine caused only a mild and transient vasoconstriction of the cerebral circulation, mediated primarily by stimulation of the superior cervical ganglia, and a small direct cerebral vasoconstrictor component. An acute tolerance to the cerebral vasoconstrictor effects of repeated increments of nicotine was also observed. The cerebral vasoconstrictor effect of nicotine was diminished in the presence of intact vagi, suggesting a cerebral vasodilator role for these nerves. In contrast, the effect of nicotine on the denervated hindlimb vasculature was a weak but sustained vasodilation. The mechanism of action of nicotine on the cerebral circulation is discussed along with the relevance of these findings to the potential health hazards of tobacco smoking in individuals with cerebrovascular insufficiency.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

Acute anoxia was produced in 80 dogs under anesthesia with sodium pentobarbital. Respiration was maintained with a Palmer's pump through an endotracheal tube. The anoxia was produced by stopping the pump and occluding the endotracheal tube. Polarizing solution (glucose-potassium-insulin) was perfused in 40 of the animals, starting three hours prior to the anoxia. The remaining 40 dogs comprised the control group. Peripheral electrocardiograms, as well as electroencephalograms, were simultaneously recorded before and during the period of anoxia. Recordings were continuously obtained until no more than one ventricular complex in a ten-second period was observed, even though the electrical brain activity had disappeared by this time.Our present experimental work suggests the beneficial effect of polarizing solutions by delaying the anoxic degradation of the electrical phenomenon of the heart and the brain.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID

摘要:

A battery of blood coagulation tests were performed on 14 acute stroke patients. Various abnormalities were found, notably elevation of blood fibrinogen, factor VIII, prothrombin, platelet factor 3, and a shortened P.T.T. The significance of these findings is discussed and they are considered to be of no importance since similar changes were noted in the blood of healthy subjects of the same age range.

ISSN:0039-2499    

出版商:OVID    

年代:1971

数据来源: OVID