Detection of endogenous albumin as an index of blood parenchymal border alteration.

We used a microdialysis technique to establish a method to detect sequential changes in disruption of the blood parenchymal border. Twelve cats were divided into two groups; one group underwent occlusion of the middle cerebral artery for 60 minutes, the other a cold injury model. Microdialysis probes were implanted bilaterally into the white matter, and dialysates were collected successively at 30 minute intervals for 6 hours in the occlusion model and 4 hours in the cold injury model. Regional cerebral blood flow was measured simultaneously using the hydrogen clearance method. The water content of the white matter was measured using specific gravity. The proteins in the dialysate were analyzed using electrophoresis with silver stain, and, with densitometric analysis, the density of the 66.2 kDa band was quantified as albumin. The ratio of this density to the preoperative density was defined as the "albumin index." On the side of the lesion in the cold injury model, this index significantly increased 3 hours after the cold injury compared with the contralateral side, and a correlation between the water content and this index was observed. The albumin index was believed to indicate the severity of disruption of the blood parenchymal border.