摘要:

Radionuclide angiography as a noninvasive procedure has become an important tool in the evaluation of cerebrovascular diseases. Determinations of arm-to-brain circulation times complemented by the transit times of the radionuclide bolus through the brain afford insight into the functional status of the vascular system of the brain. Delays in perfusion, asymmetries in appearance, and washout of the radionuclide material can be correlated with disease entities. However, as with many procedures elevated to the status of a screening test, the possibility of false-positive and false-negative results exists. Two cases of bilateral carotid occlusion are presented, showing normal or only delayed, fairly symmetrical brain perfusion. The appearance of the radionuclide flow in the neck in AP and lateral views gave no suggestion of the involved deficits. Even multiple-projection imaging might fail to demonstrate major vascular obstructions. However, attentive study of these projections might yield interesting evidence of unexpected collateral flow systems.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Molecular mechanisms accounting for the vulnerability of brain to ischemic damage are incompletely understood. To assess the role of membrane integrity, phospholipid metabolism is investigated in subcellular organelles of brain following varying degrees of ischemia. Global brain ischemia is produced in rabbits by combining hypotension and hypoxia (4% oxygen). Restoration of blood pressure and oxygen after a three-minute isoelectric EEG results in full recovery, while a five-minute isoelectric EEG results in either a lack of recovery or neurological deficits. Quantitative analysis of seven phospholipids in subcellular organelles shows no consistent pattern of phospholipid changes following ischemia. Incorporation of radioactive phosphate, on the other hand, discloses moderate alterations following five-minute ischemia. These findings indicate that brain ischemia provokes phospholipid changes, but their role in impairing membrane integrity and in initiating irreversible ischemic brain damage is uncertain.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Sixty-one male patients with ischemic thrombotic cerebrovascular disease (ITCVD) and 61 age-matched controls were studied to determine the interrelationships between the primary risk factors of ITCVD. Impaired carbohydrate metabolism in ITCVD was reflected in the significantly greater number of abnormal oral glucose tolerance tests (GTT) and type IV lipoprotein abnormalities when compared to controls. Elevated uric acid and triglyceride levels also were observed in ITCVD. Glucose and immunoreactive insulin (IRI) response curves in ITCVD were elevated and exhibited delayed peaks despite the normal or abnormal classification of GTT, indicating that insulin is ineffective in restoring glucose to normal levels. In the ITCVD and control groups with abnormal GTT the free fatty acid (FFA) levels were elevated at fasting and lacked the characteristic rebound at two hours observed in subjects with normal GTT, supporting the theory of a glucose-FFA cycle and its role in carbohydrate disturbances.

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0039-2499    

出版商:OVID    

年代:1975

数据来源: OVID