[A mechanism of development and resolution of vasogenic brain edema]

To investigate the mechanism of development and resolution of vasogenic brain edema, authors have infused the mock CSF containing 35S-sodium thio-sulfate via a thin needle into the white matter of either normal cat's brain or into the edematous brain. The animals which were used in these experiments were divided into four groups (L20, L45, C20, C45). In the groups of animals subjected to a cold lesion (L20, L45), a small craniotomy was performed over the right frontal pole. A cold injury edema was produced 24 hours prior to the experiment. Na-Fluorescein (2 ml/kg) was given intravenously just prior to the cold lesion to later visualize the extent of the edema. For the positioning of the four needles in the brain, the coordinates were used according to the Horsley-Clark method and the atlas of Reinoso-Suarez. The location of tissue infusion (TIP) corresponds to a point approximately 3.0 mm before the frontal apex of the right lateral ventricle. The infused artificial CSF was mixed with 35S sodium-thiosulfate and stained with Evans Blue to check the extent of propagation of the infused solution. This solution was infused into the tissue at the point TIP with a rate of 0.20 ml/hr in groups C20 and L20 and 0.45 ml/hr in groups C45 and L45. Both lateral ventricles and cisterna magna were cannulated, and a ventriculo-cisternal perfusion with an artificial CSF was established through the right lateral ventricle with a perfusor. The perfusion rate was 2.25 ml/hr. The cisternal outflow was collected during every 15 min. for the activity and volume measurement. Tissue water content was determined by the drying method.(ABSTRACT TRUNCATED AT 250 WORDS)