摘要:

The retinal arterial diameter and its response to changes in perfusion pressure were measured by means of a fundus camera in 65 normal subjects. A reduction of effective MABP was induced by a postural change from a recumbent to an erect position. A small but significant increase in retinal arterial diameter was observed by reduction of the perfusion pressure in all subjects. The reduction of retinal arterial reactivity in response to blood pressure changes (-% change in diameter/delta effective MABP) was significantly correlated with advancing age (p less than 0.01). No significant correlations were observed between the retinal arterial reactivity, magnitude of the retinal arterial diameter (range: 60–140 mu), and systemic blood pressure (range of MABP: 75–110 mmHg). These results indicate that the retinal artery has an autoregulatory mechanism which is influenced by aging.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

rCBF was measured by 133Xenon inhalation technique in 39 patients with unilateral carotid artery occlusion in a subacute-chronic stage. Resting flow values (ISI) varied between 23.7 and 52.4 ml/100 g/min. An almost constant finding was interhemispheric asymmetry, the degree of which was correlated with the severity of the initial symptoms. An ischemic focus was an insignificant finding. The CO2 response was normal in patients with angiographic signs of circle of Willis collateral flow and without significant contralateral carotid stenosis, whereas it was impaired in patients with a retrograde ophthalmic flow or collateral flow via the circle of Willis and contralateral carotid stenosis greater than or equal to 50%. It is concluded that the CO2 response in useful rCBF variable and may be applied for analysis of collateral flow capacity in patients with carotid artery occlusion considered for bypass surgery.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

rCBF was measured by 133Xenon inhalation at rest and during pCO2 manipulation in 19 patients prior to and at various times after STA-MCA bypass surgery. The resting flow increased gradually postoperatively, seemingly more due to progressive clinical recovery from the original neurologic disability than due to the surgical intervention. CO2 reactivity increased in some patients, more in those who preoperatively had the poorest reactivity. The negative relationship between preoperative reactivity and postoperative change in reactivity was highly significant. These observations are consistent with the interpretation that the surgery did not significantly affect the resting flow level but did augment the collateral reserve in those cases in which it had been most severely impaired by the arterial lesion.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The effect of haematocrit on the sequelae of carotid occlusion has been studied in the gerbil stroke model. In 72 animals one carotid artery was clipped. After 30 minutes, the area of cerebral hemisphere filling with a carbon suspension administered intravenously was measured on coronal brain slices and related to the haematocrit. Exchange transfusion of autologous packed red blood cells or plasma produced a haematocrit range of 26% to 59%. At high haematocrit a larger area of non perfusion was more commonly encountered, and the anterior cerebral artery territory was more frequently affected along with that of the middle cerebral. Fifty-seven animals had temporary occlusion of both carotid arteries. Survival was adversely affected at high haematocrit. The role of haematocrit in affecting the pathophysiology of cerebral ischaemia is discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The effect of arterial hypotension on cerebral cortical tissue levels of adenosine triphosphate (ATP), phosphocreatine (PGr), lactate, and reduced nicotinamide adenine dinucleotide (NADH) was studied in male Wistar rats with unilateral carotid ligation exposed to arterial by hypoxia (PaO2 25 torr) for 20 min. while the body temperature was maintained at 32 degrees C and 27 degrees C. Brain metabolite levels were normal in normotensive hypothermic animals exposed to hypoxia, but reduction in arterial pressure to 75 torr caused a significant (p less than 0.05) decrease in ATP and PCr values and a significant increase in lactate and NADH levels. These changes were comparable to those of normothermic normotensive, hypoxic animals. Furthermore, there was no significant differences in the brain metabolite levels between the two hypotensive hypoxic groups. These results indicate that arterial hypotension severely alters the cerebral protective effect of hypothermia against injury caused by hypoxia, and that further reduction in body temperature (from 32 degrees C to 27 degrees C) will not prevent the harmful effect of hypoxia upon the brain in hypotensive rats.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

In a double-blind multicenter study, 124 patients with transient ischemic attacks were randomly allocated to one of two groups treated with aspirin (ASA) or sulfinpyrazone respectively. Patients were followed up to assess the relative efficacy of the two treatments in the prevention of the outcomes of stroke, myocardial infarction, vascular death, and worsening or no improvement of TIAs. No significant difference was observed between the two treatments at the end of the follow-up period. Statistical analysis revealed a significant interaction of sex, treatment, and occurrence of events. Analysis of the results according to sex showed that male patients treated with ASA had a highly significant benefit (p less than 0.001) with a 53% risk reduction for further events. In female patients, sulfinpyrazone showed a favorable trend which was not statistically significant.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

We investigated the potential of aspirin and dipyridamole in combination to inhibit thrombus formation by comparing endarterectomized segments of 20 dog carotid arteries in animals treated with pre- and post-operative aspirin and dipyridamole to 20 arteries from untreated animals and 20 arteries from animals receiving intra-operative heparin. The temporal profile of thrombus formation was assessed by means of angiography, light microscopy, and scanning electron microscopy at time intervals ranging from 30 minutes to three months from the time of surgery. All of the aspirin-dipyridamole vessels remained patent and only one had significant gross thrombus formation. This contrasted to six occlusions and six significant gross thrombi in the control group and one occlusion and six significant gross thrombi in the heparin group. The combination of oral aspirin and dipyridamole minimizes thrombus formation in the highly thrombogenic lesion created by carotid endarterectomy in the dog.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

In 26 patients with recent rupture of an intracranial saccular aneurysm the CSF concentrations of serotonin (5-HT) were measured repeatedly by a radioimmunoassay. The 5-HT level in ventricular CSF collected between the 2nd and 15th day after SAH ranged between less than 2 and 5 nmol/l. These did not differ from the levels found in the ventricular CSF (less than 2–3 nmol/l) and lumbar CSF (less than 2–3 nmol/l) of control patients. 5-HT concentrations did not correlate with the severity of angiographical vasospasm, nor with CSF pressure or clinical grade. In two patients with severe postoperative vasospasm, however, cisternal CSF collected during operation and contaminated by fresh blood showed 5-HT concentrations exceeding 25 nmol/l. Thus, although these results do not support the conception that 5-HT plays a major role in sustaining delayed vasospasm, they suggest that 5-HT liberated from platelets may be operative in the initiation of cerebral arterial spasm.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The occurrence of epileptic seizures was investigated in 141 patients with angiographically proven carotid or MCA occlusive disease. Epileptic seizures occurred some time during the clinical course of the disease in 17.3% of carotid patients and in 10.8% of MCA patients, being mainly represented by partial motor seizures. The pattern of occurrence of seizures in the natural history of cerebral arterial disease was different in the two groups. In the carotid group, epilepsy was the presenting symptom in 6.7% of patients, whereas no MCA patient had seizures prior to the appearance of a neurological deficit. Since epileptic seizures may complicate an otherwise asymptomatic carotid obstruction, angiography should be performed whenever the other standard investigations, including CT-scan, fail to reveal the cause of late-onset epilepsy.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Intracranial arteriovenous malformations (AVMs) are congenital communications between the cerebral arteries and veins without an intervening capillary network. The association of the malformations with other vascular lesions such as intracranial aneurysms has previously been reported. We have reviewed 132 consecutive patients with intracranial AVMs evaluated angiographically at New England Medical Center. In addition to the expected high incidence of saccular aneurysms, a high incidence of arterial infundibula was found. A review of the association between the AVMs, aneurysms and infundibula, and possible etiologic factors in the relationship forms the subject of this report.

ISSN:0039-2499    

出版商:OVID    

年代:1982

数据来源: OVID