Comparison of Asymmetry in Cerebral Blood Flow Between Brain Hemispheres Using Digital Subtraction Angiography

BACKGROUND AND PURPOSE: Recently, endovascular techniques have gained significant therapeutic potential for both treatment and prevention of stroke. Cerebral angiography, which is an essential component of these procedures, has been used to provide morphological information regarding condition of blood vessels. In this study, we propose to determine the possibility of acquiring information regarding cerebral blood flow (CBF) in addition to morphologic information from data routinely available during angiography. METHODS: Digital subtraction angiography sequences were obtained for eight patients having occlusive disease in internal carotid artery (ICA) territories. Two regions-of-interest (ROIs) corresponding to the two brain hemispheres on AP view were delineated. For each image, the average pixel value within each ROI was calculated and used to generate time-density curves. Indices obtained from each curve were compared with each other and with the results obtained from the single photon emission computed tomography (SPECT) studies performed a pre- or postangiography procedure. RESULTS: Comparison between ICA stenosis and cerebral perfusion measurements revealed that cerebral perfusion deficit can be independent of arterial occlusive disease. The indices obtained from the time-density curves exhibit a correlating trend with the results from SPECT studies. However, lack of sufficient sample data prevented any meaningful statistical analysis to be conducted. CONCLUSIONS: We have developed a technique for utilizing the angiographic data for the important task of routinely and easily measuring CBF. Availability of CBF measurements during cerebral angiography may favorably impact upon the appropriate use of endovascular procedures and potentially contribute to the reduction of morbidity and mortality associated with stroke.     

The combination of platelet-derived growth factor-BB and insulin-like growth factor-I stimulates bone repair in adult Yucatan miniature pigs

The combination of insulin-like growth factor-I and platelet-derived growth factor-BB has previously been shown to stimulate healing of soft tissue wounds and the formation of bone and ligament around teeth. The purpose of the present study was to evaluate the effects of platelet-derived growth factor-BB and insulin-like growth factor-I individually and in combination on the healing of osseous wounds. Four standardized cortical wounds were created in each tibia of 11 adult Yucatan miniature pigs. The wounds in one tibia per animal were treated with either purified recombinant human insulin-like growth factor-I, platelet-derived growth factor-BB, or both in a methylcellulose gel. The wounds in each contralateral tibia received placebo gel alone. Coded serial sections of each wound were evaluated by computer-aided histomorphometry 21 days after surgery. The area and perimeter of the newly formed mineralized callus, the thickness of the total callus, and the percentage of mineralized tissue within the callus were significantly increased compared with the values of matched controls only in wounds treated with a combination of insulin-like growth factor-I and platelet-derived growth factor-BB. No significant differences in the measured parameters of callus formation were found in wounds treated with either insulin-like growth factor-I or platelet-derived growth factor-BB alone. Cartilage was present only in sites treated with insulin-like growth factor-I alone. These results suggest that the combination of platelet-derived growth factor-BB and insulin-like growth factor-I stimulates bone formation in wounds in long bones of adult animals and that these growth factors act via different pathways during the repair process.     

Amputation in elderly and high-risk vascular patients

Fifty-eight patients underwent lower limb amputation for arterial disease over a 30-month period. Mean age of the patients was 72 years. Cardiopulmonary and metabolic risk factors were present in the majority of the patients. Postoperative one-year and three-year mortality rates were 24, 40, and 76%, respectively. Contralateral amputation was required in one-third of the patients after a mean period of eight months. Only younger and healthier patients returned to a meaningful social life after appropriate prosthetic fitting. In view of the high mortality and morbidity rates, above-knee amputation seems a better choice than below-knee amputation in these elderly and high-risk patients.