摘要:

Oxygen availability (O2a) and local cerebral blood flow (CBF) as H2clearance were measured at the same point, taking advantage of the sensitivity of the platinized platinum electrode to both H2and O2in gerbils following ischemia made by transient bilateral carotid artery ligations. Both O2a and CBF were zero during carotid ligation. During postischemic reperfusion there was a qualitative correlation between the two, with a tendency for the O2a recovery to be less than that of CBF in the first hour and greater in the second hour. These differences in the time course of O2a and cerebral blood flow may be accounted for by altered oxygen consumption in relation to tissue perfusion, or by altered oxygen sensitivity of the electrode. The results demonstrated the feasibility of making oxygen and flow measurements at the same point in tissue.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Nine adult survivors of out-of-hospilal presumed cardiogenic cardiac arrest, who remained unresponsive for longer than their third hospital day and who eventually were discharged from the acute care hospital, are reported. Their neurological outcome fell into three distinct categories: (a) a persistent vegetative state, (b) able to follow some simple commands but requiring total nursing care, and (c) able to perform most activities of daily living but unemployable because of marked organic mental deficits.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Arteriolar responses were measured on the cerebral surface of the mouse brain using an image splitter and TV monitor. The response to locally applied norepinephrine (NOR) was significantly more frequent for vessels greater than 30 M ID. than for smaller vessels. However, even the smaller vessels were frequently constricted by NOR in doses of 5 ng per milliliter. Reserpine (S mg per kilogram) failed to alter the response to NOR at either 24 or 72 hours after reserpinization. At 48 hours the threshold dose of NOR was reduced, but the effect was slight (two-tailed, P = 0.08). Both propranolol (10 6M3 and phentolamine (10 SM) blocked responses to 5 ng per milliliter of NOR, but neither agent altered resting arteriolar diameter. Isoproterenol, tyramine, and histamine had no effect. Serotonin (SHT) constricted the arterioles but did not potentiate the response to NOR. Additive or potentiated effects were not observed with NOR, 5HT or histamine in any combination. These data indicate the presence of alpha-adrenergic receptors in murine cerebral surface arterioles, but do not establish a significant tonic effect of norepinephrine. The existence or role of a beta-receptor in these murine cerebral surface arterioles remains an unsettled question.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

The upper limit of autoregulation of cerebral blood flow was investigated in eight young baboons with the intracarotid133xenon clearance method. Blood pressure was increased by intravenous angiotensin infusion. Autoregulation was effective during blood pressure increase from normotensive levels to a mean pressure of 130 to 139 mm Hg. At this pressure, cerebrovascular resistance reached a maximum. With further blood pressure increase, autoregulation was broken, and the vascular resistance dropped significantly. This flow increase was restricted to the fast component of the133xenon clearance curve, leaving the slow component unchanged. Blood pressure was kept above the upper limit of autoregulation for 10 to 114 minutes. When the pressure was subsequently decreased, flow values returned to normal in half of the animals, while cerebral hyperemia persisted in the other half. The latter group of animals had been kept above the upper limit of autoregulation for a comparatively longer time, and the persistent hyperemia may have been caused by overstretching of the arteriolar walls. In some animals, angiotensin was infused into the internal carotid artery prior to the autoregulation study in doses not influencing systemic blood pressure. No pharmacological action of angiotensin on CBF was noted.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Cerebral autoregulation and vasomotor responsiveness to carbon dioxide were measured quantitatively in normal baboons before and after intravertebral or intravenous infusion of the beta-adrenergic blocking agent, propranolol hydrochloride (Inderal®). Continuous measurements were made of cerebral blood flow (CBF: measured as bilateral internal jugular venous outflow using an electromagnetic flowmeter), cerebral perfusion pressure (CPP), arterial Po2and Pco2and venous Po2, cerebral arteriovenous oxygen difference and endotracheal Pco2. The autoregulation index (A.I. = ACBF/ACPP) and the chemical index (C.I. = Δ CBF/Δ Paco2) were used as quantitative measures.The effect of intravertebral infusion of propranolol (0.01 mg per kilogram of body weight) was compared to intravenous infusion of identical doses of propranolol so that any specific action of the drug on a possible vasomoto center in the brain stem may be assessed. Significant reductions (-25%) in CBF and CPP followed both intravertebral and intravenous infusion of propranolol. Cerebral metabolic rate for oxygen (CMRO2) decreased significantly ( - 18%) and cerebrovascular resistance (CVR) increased significantly ( + 19%) after intravertebral infusion of propranolol while less significant changes ensued following intravenous infusion of propranolol. Cerebral autoregulatory vasoconstriction during increases in CPP was significantly enhanced following both intravertebral and intravenous propranolol. Cerebral autoregulatory vasodilatation during decrease in CPP was not influenced by propranolol. Cerebral vasodilatory responsiveness to CO2inhalation was significantly inhibited following intravertebral propranolol while no significant change resulted from intravenous propranolol. Cerebral vasoconstrictive responsiveness to hyperventilation was not influenced by propranolol.These results indicate that the CBF and CMRO2are reduced by a pharmacological beta adrenergic blockade with propranolol hydrochloride.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Forty patients with cerebral infarction associated with occlusion of the internal carotid artery (ICA) or the middle cerebral artery (MCA) were treated with hyperbaric oxygenation (HO). EEC analyses were performed regularly in order to assess the course of the cerebral lesion. Patients in an early post-stroke stage (III B) and patients in a chronic post-stroke stage (IV) had the changes in EEC analysis and neurological findings distributed evenly between these two groups.In 27% of the cases, the improvement was considerable, 53% had moderate improvement, and 20% showed no change of condition. The improvement mainly consisted of an increase of alpha-wave and betawave activity over the affected brain region. We were able to show this fact clearly by means of the EEG-analj sis-system applied. The results show that (a) hyperbaric oxygenation therapy (HOT) has a very favorable influence upon the course of disease, and (b) simultaneous application of HOT and EEC analysis allows for a differentiation between reversible and irreversible post-stroke changes in brain tissue.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

In cats, total cerebral ischemia of one hour's duration was produced by arterial clamping and lowering of the blood pressure. Following ischemia the brains were recirculated with blood for various periods between 30 minutes and six hours. CBF and uptake of O2and glucose were determined and correlated with the electrophysiological recovery of the brain.In four of 20 cats recovery was absent because of respiratory or circulatory insufficiency. In 16 cats signs of progressive electrophysiological function returned. These animals exhibited postischemic hyperemia; electrical excitability of the brains recovered within IS minutes, and the adenylate energy charge returned to more than 95% of the preischemic value within 30 minutes. O2uptake was significantly reduced for about one hour, but returned to or above normal as soon as spontaneous ECoC activity began to reappear. Glucose uptake was initially in the normal range until the cerebral glucose stores were replenished, but then followed a time course similar to that of O2.It is concluded that aerobic glycolysis may return after one hour's ischemia if the brain is adequately resupplied with glucose and O2.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

Spontaneous cerebellar hemorrhage is of difficult clinical diagnosis. The causes can be varied, but the hemorrhage is most often associated with hypertensive cardiovascular disease. The neurological symptomatology is complex and often misleading. The diagnosis is mainly dependent on familiarity of the eye signs seen in this disease. Among these, the spontaneous unilateral eye closure is presented as an additional striking manifestation. The displacement of the brain stem by the hematoma is frequently associated with a seventh nerve palsy on the side of the hemorrhage. The patient, in an effort to obviate the diplopia caused by the gaze dissociations and extraocular motor palsies, has only the option to close the eye on the noninvolved side of the face, and thus the eye remaining open is on the side of the cerebellar hematoma. This paper presents reports of two patients with these symptoms.

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1976

数据来源: OVID