摘要:

The purpose of this study was to determine the primary effects of subarachnoid hemorrhage (SAH) on cerebral oxidative metabolism and energy balance. Rhesus monkeys were prepared so that cerebral metabolic consumption rates of oxygen, glucose and the lactate/pyruvate ratios of CSF were estimated after isobarically and hyperbarically induced SAH. A regional analysis was performed on brain sections after similarly induced SAH in the rat, for levels of tissue, glucose, lactate, pyruvate, ATP, ADP, AMP, PCr and the partition of hexokinase between soluble and mitochondrial bound forms. The presence of intracranial hypertension was associated with an immediate ischemia, and increased cerebral glucose extraction was initially noted. Specific tissue substrate concentrations in rat brain indicated that fresh intracisternal hemorrhage is associated with decreased glycosis at a time when high energy phosphate levels are normal. It is concluded that intracranial hypertension hastens the onset of ischemia after SAH. SAH alone produces a decrease in cerebral energy requirements which secondarily depresses the rates of consumption of energy yielding substrates. The depression in metabolic rates may be mediated through a brain stem mechanism.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

TheMacaca irusis a monkey species that is highly susceptible to experimental cholesterol atherosclerosis of the aorta, coronary and cerebral arteries and cutaneous xanthomatosis-like lesions induced by feeding a diet high in cholesterol and/or coconut oil for 14 months.The monkeys fed an atherogenic diet were divided into two groups: monkeys receiving excess sodium and controls. The excess sodium group showed a significantly higher systolic blood pressure as compared with the control group; however, elevation of blood pressure was mild and was not considered as significant hypertension.The loading of excess sodium chloride in monkeys fed an atherogenic diet did not enhance severity of atherosclerosis of the aorta, coronary and cerebral arteries.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

A retrospective study was made of a group of 44 patients with arteriosclerotic occlusion of the internal carotid artery trying to identify a group that might benefit from extracranial-intracranial arterial bypass. Eight of the 44 patients died of cerebral infarction. Seven of these deaths were due to the cerebral infarction that prompted the arteriogram and the only fatal infarct during the period of follow-up occurred in the opposite cerebral hemisphere. Four nonfatal strokes occurred during the follow-up period, and these also were in the cerebral hemisphere contralateral to the carotid occlusion. We conclude that the role of extracranial-intracranial arterial bypass is limited to the occasional patient who has recurrent symptoms due to vascular insufficiency in the cerebral hemisphere distal to an occluded carotid or middle cerebral artery. The main role of surgery appears to lie in the opening of the occluded carotid artery in selected patients with acute stroke and in the prophylactic repair of contralateral carotid stenosis.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Our earlier studies showed no secondary postischemic (PI) rise in cisterna magna pressure (CMP) for ten hours and no significant reduction in CBF (integrated N2O desaturation technique) for three and one-half hours after 15 minutes of systemic circulatory arrest. However, transtentorial pressure gradients may have developed, and CBF changes may have been masked by limitations of the N2O method in low flow states. In this study, 12 dogs were subjected to 15 minutes of aortic occlusion and studied for two hours PI. Immediately after restoration of circulation, cisterna magna, supracortical and lateral ventricle pressures rose to 35 to 40 torr, concomitant with a threefold increase in cerebral blood flow (133Xe clearance technique). By 30 minutes postischemia, cisterna magna and supracortical pressures had returned to control values but lateral ventricular pressures normalized slower. CBF decreased to and remained at 50% of preischemic values after 40 minutes PI. Cerebral glucose uptake increased markedly immediately PI, then fell significantly below control values at 45 minutes. Cerebral O2uptake was significantly reduced, although less than for glucose, between 30 and 60 minutes PI. Global ischemia for 15 minutes is followed neither by a secondary rise in intracranial pressure nor by a cerebrospinal fluid pressure gradient but rather by hypoperfusion and defective glucose metabolism.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Baboons were anesthetized with halothane or pentobarbital prior to middle cerebral artery (MCA) occlusion to test the protective effect of barbiturates against stroke in primates. Significantly less infarction was found in animals that received 90 mg per kilogram pentobarbital or more than occurred in control animals. Because of cardiovascular and ventilatory complications at high doses of barbiturate, however, therapeutic trials to suppress stroke in the human must await further identification of an effective regimen which includes a safe barbiturate dose.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

A coordinated system of care for stroke patients is established in the community of Fall River, Massachusetts, involving the Stroke Unit of Union Hospital, the Rehabilitation Unit of Earle E. Hussey Hospital, and the Fall River District Nurse Association. Long-Range Evaluation Summary (LRES) data collection forms developed at the Tufts University Medical Rehabilitation Research and Training Center (RT-7) are being used to reflect the functional status of the patient at any given point in time. Of 164 patients the Stroke Unit returned 49% home and the Rehabilitation Unit returned another 9% home. This systematic approach to functional assessment relates the disease-state and disability to outcomes of care. By taking into account the several-fold nature of outcome determination it is possible to analyze program effectiveness because such uniform descriptions, over time, permit us better to relate the population under care, its key characteristics for these purposes, and the comprehensiveness of problem identification and planning all at the same time.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

This study was undertaken to evaluate the brain hemodynamics of the primate (Macaca mulatta) in the conscious and anesthetized state. A polarographical circuit was utilized for repetitive measurements of local and average total cerebral blood flow in the conscious state, during analgesia/paralysis, and in the anesthetized state. The electrochemical considerations and in vitro testing are described. Blood flow values were highest in sensory and motor cortex (92.5 ± 3.5 ml/100 gm per minute and 86.2 ± 2.6 ml/100 gm per minute), while there were no significant differences found between other regions of association cortex. Mean deep gray matter blood flow values ranged between 57.6 ± 3.8 and 69.2 ± 3.4 ml/100 gm per minute. The mean local blood flow for the centrum semiovale was found to be 19.5 ± 1.2 ml/100 gm per minute and that for pontine tegmentum was 58.1 ± 3.5 ml/100 gm per minute. At any one electrode locus, at steady state levels of arterial blood gases, the reproducibility of blood flow ranged between 11% and 18%. Seventy-five percent nitrous oxide/25% oxygen in combination with a paralytic agent produced a questionably significant drop in caudate nucleus blood flow. The depressant effects of anesthetic doses of sodium pentobarbital on cerebral blood flow, however, were significant at most electrode sites. These data indicate that the measured blood flow rates within small brain volumes are critically affected by barbiturate anesthesia and seriously question the value of published reports in which these agents were utilized.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The cerebral vasospasm produced by blood, fractions of blood, and blood-borne agents administered intracisternally was studied arteriographically to attain a better understanding of the genesis of vasospasm. The results indicate this phenomenon is multifarious in origin, involving a number of spasmogens. Whole blood, platelets, platelet extracts, some isolated components of platelets, plasma, thrombin, histamine, serotonin and prostaglandins F1α, E2and F2αproduced a significant incidence and duration of spasm. Norepinephrine and prostaglandin E1were inactive. Spasm produced by arachidonic acid and red blood cells was of questionable significance.Compared to whole blood, thrombin usually produced spasm which was more delayed in onset while most other active substances produced a shorter-lived spasm. However, among the pure substances tested, serotonin, prostaglandin E2and prostaglandin F2αinduced spasm in small doses which most nearly resembled that observed with whole blood.The hypothesis that the course of spasm depends upon synthesis of spasmogens by brain and blood is advanced. Prostaglandin synthesis plays a major role in this concept.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The skin blood pressure was measured in the forehead using a photoelectric method in 12 subjects with occlusion and 16 subjects with arteriosclerotic stenosis of the internal carotid artery and compared to 18 normal subjects. The skin blood pressure was in average 37 mm Hg (SD 15) in the patients with occlusion, 44 mm Hg (SD 16) in the patients with stenosis, and 46 mm Hg (SD 10) in the normal subjects. During interruption of the blood supply from the external carotid artery (manual compression of the ipsilateral superficial temporal artery), the skin blood pressure was reduced in average 14 mm Hg in the patients with internal carotid occlusion, 8 mm Hg in the patients with stenosis, and not at all in the normal subjects. Skin blood pressure measured on the arm was in all groups 10 to 20 mm Hg higher than the diastolic arm blood pressure. It is emphasized that this method, as well as other methods using extracerebral registration in an attempt to evaluate the intracerebral arteries, is interesting from a hemodynamic point of view, but is of less diagnostic value in the single patient when compared to the arteriographical investigation.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Brain lactate, pyruvate, and arterial acid-base balance were measured in normotensive rats (NTR) and spontaneously hypertensive rats (SHR) 60 minutes after bilateral carotid artery ligation. Brain lactate and lactate-pyruvate ratios were significantly increased in both SHR and NTR following carotid occlusion, although lactate increase in the former was six and one-half times greater than in the latter. These findings suggest that bilateral carotid occlusion in SHR may cause more severe circulatory changes which result in increased anaerobic metabolism. Furthermore, higher brain lactate was concomitant with lower arterial carbon dioxide tension. The mechanism of spontaneous hyperventilation following cerebral ischemia was discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID