ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A simple implanted device was used to occlude acutely the left middle cerebral artery (MCA) of 16 conscious cats. Eight received no treatment and 8 were given intravenous mannitol (1.2 gm/kg) at the time of occlusion. The initial neurological findings in both groups were similar, that is, agitation, forced circling, and right hemiparesis. The treated cats remained alert but the untreated cats became lethargic and drowsy. Perfusion with a mixture of colloidal carbon and buffered paraformaldehyde was carried out from 30 minutes to 6 hours following MCA occlusion. Results of morphological examination of brains from the treated and untreated groups suggested that mannitol had a protective effect upon cerebral tissue during the primary phase of acute focal ischemia. Light microscopic analysis of neuronal alterations demonstrated considerable preservation of neurons in brains of treated cats. Beneficial effect of mannitol was attributed partly to prevention of capillary narrowing and suppression of ischemic cerebral edema.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

In a canine stroke model, dose dependent protection by postocclusion pentobarbital was suggested from 10-40 mg/kg. In 28 dogs investigated (10 from a previous study) a distinct, significant reduction in right cerebral hemisphere infarction occurred in animals given 15-20 mg/kg pentobarbital intramuscularly 1 hour postocclusion. Increased dosages did not alter statistically the infarct size and 2 dogs at the 50 mg/kg and 80 mg/kg levels died of barbiturateinduced respiratory failure.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

A new method of determining the rate of glucose utilization in brain regions of individual rats has been used to measure the dose dependency of the reduction of the metabolic activity of the cerebral cortex by pentobarbital. Cerebral cortical glucose utilization is depressed to a basal level of 44% of the control rate when cerebral pentobarbital levels exceed 50 μg per g of tissue. The major portion of this effect occurs between the cerebral pentobarbital range of 10-20 μg per g, which can be achieved by 1/5 to 1/10 the normal anesthetic intraperitoneal dosage. If a depression of brain metabolism is responsible for the previously reported protection of the brain from ischemic damage, these data suggest a substantial reduction of brain metabolic rate is achieved in the rat at a barbiturate dosage which may be therapeutically relevant in the human after acute brain ischemia.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

In 1 year 6 patients with prosthetic heart valves (PHVs) treated with anticoagulants suffered intracranial hemorrhage. In 4, hemorrhage occurred into the site of a recent non-hemorrhagic infarction. In the others, both of whom had endocarditis, hemorrhages probably occurred as the result of rupture of a mycotic aneurysm. Five patients were treated with warfarin, 1 with heparin. In all patients the level of anticoagulant activity was greater than times control. Five patients were in atrial fibrillation; 1 was hypertensive. The diagnosis of intracranial hemorrhage was made and location and extent accurately determined by computed tomography (CT). Three patients underwent surgery and 2 are alive with only minor neurological deficits. Among the 3 patients who did not undergo surgery 2 died and 1 is alive with a moderate neurological deficit. The management of PHV patients with use of anticoagulants is discussed in terms of the mechanisms involved in intracranial bleeding. Emphasis is placed on prevention of emboli, discontinuation of anticoagulants once non-hemorrhagic infarction has occurred and the primacy of CT scan in diagnosis when hemorrhage is suspected. The special problems of anticoagulation in the presence of endocarditis are also discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

It has been hypothesized that acute lesions of the brain enlarge through an autodestructive process. Serotonin (5HT), a potent cerebral vasoconstrictor, is believed by some to mediate the process by reducing cerebral blood flow (CBF) in tissue surrounding the lesion. The hypothesis was tested in cynomolgus monkeys anesthetized with ketamine and nitrous oxide. Craniectomies, 7 mm in diameter, were performed in each parietal area. The dura was opened and polarographical electrodes of thin platinum wire were inserted into the parietal lobe cortex of each hemisphere. Mock cerebrospinal fluid (CSF) was irrigated continuously onto the brain surrounding the electrodes, from which local CBF was determined repeatedly by the hydrogen-clearance technique. After baseline CBF was established, solutions of 5HT in mock CSF (in concentrations of 5 × 10−7M, 5 × 10−5M, and 5 × 10−3M) were irrigated onto one hemisphere while the opposite hemisphere served as control. SHT failed to change CBF. Although 5HT is a potent vasoconstrictor, under physiologic conditions it apparently is unable to effect hemodynamically significant constriction of the peripheral cerebral vasculature of the anesthetized monkey brain.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Unilateral stimulation of the cervical sympathetic in dogs had no effect on cerebral blood flow (CBF) measured by the venous outflow technique. Since this technique measured CBF from both cerebral hemispheres, small changes induced by unilateral stimulation could have been masked by a large constant CBF measured from the contralateral hemisphere. To test this possibility the effect of simultaneous bilateral sympathetic stimulation was studied when the dog was breathing either normal air or a gas mixture of 10%CO2. During normocapnia, no changes in CBF occurred; during hypercapnia CBF increased 19% following passively the increase in blood pressure. These data indicate that bilateral stimulation of extracranial sympathetic nerves does not exert a significant effect on CBF. We show mathematically and experimentally that unoccluded anastomoses will cause CBF to appear to decrease in response to sympathetic stimulation. This may explain why others have observed changes in CBF during sympathetic stimulation.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Forty consecutive patients undergoing thromboendarterectomy for total internal carotid artery occlusion were studied in an attempt to determine a) whether careful case selection could be expected to reduce future postoperative mortality and morbidity, b) whether the achieved patency rate justified early operation and c) whether patients in whom patency was restored and maintained had a better long-term prognosis. The results show that a group of patients can be selected that will have low postoperative mortality and morbidity. The success rate for restoration of blood flow is high, particularly if the operation is performed soon after occlusion. The long-term prognosis in patients in whom patency of the internal carotid artery is restored and maintained appears to be better than in those with persistent occlusion of the carotid artery.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

The etiologic and prognostic features which characterize cerebrovascular disease in the later decades of life are not applicable in younger patients. The records of 58 patients who had suffered cerebral infarction between the ages of 15 and 40 were reviewed in order to study these features. Fifty-five percent of the patients were found to have had an identifiable etiology for their cerebral infarction, with nearly half of these suffering from embolic infarction of cardiac origin. In 45% no clear etiology could be established but hypertension was prevalent in those patients between 31 and 40 years of age. Follow up data were obtained on 68% of the hospital survivors; nearly 3/4 of them had completely recovered or had improved.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID

摘要:

Dilated episcleral vessels associated with ipsilateral internal carotid artery occlusions have been previously reported though not widely appreciated. These ocular changes have been presumed to be manifestations of ocular ischemia. The authors have recently encountered this sign in seven patients and in none was there evidence of ocular ischemia. In addition to an ipsilateral internal carotid artery occlusion, arteriograms demonstrated that the major source of blood supply to the homolateral cerebral hemisphere was by retrograde flow through markedly enlarged ophthalmic arteries filled in retrograde fashion from dilated external carotid collateral channels in the orbit. This association of dilated episcleral arteries as a sign of increased orbital blood flow and the major source of collateral blood supply to the homolateral cerebral hemisphere has not been previously reported. We reemphasize the importance of a careful examination of the episcleral vessels in patients suspected of having internal carotid artery occlusions.

ISSN:0039-2499    

出版商:OVID    

年代:1978

数据来源: OVID