Tetsuya Sakamoto

Ultrastructural Observation on the Infarctic Sequential Changes in the Cerebral Tissue of Dog

Ischemic changes in small vessels, especially in capillaries, were investigated by electron microscope. Samples were taken from the ischemic foci in the thalamus of 18 dogs which were subjected to various cerebrovascular occlusions from 15 minutes to 24 hours by our method of producing thalamic infarction in dogs. After 30 minute occlusion, swelling of perivascular astrocytic processes was seen. After 1 hour occlusion, swelling of pericytes was seen. After 2 hours occlusion, swelling of endothelial cells was seen. Blebs were found in the lumen of capillaries after 3 hours. Dehiscence of tight junctions was rarely observed after 6 hours occlusion, but after 12 hours occlusion it was frequently found in capillaries and venuoles which had succumbed to necrosis. Diapedesis from necrotic capillaries and venuoles was found in the 12 hour occlusion group. After 24 hours occlusion, numerous neutrophiles appeared within the blood vessels and some of them infiltrated into softened areas.

Arrest Reaction in Man

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotactic operation we observed peculiar phenomena caused by electrical stimulation t

Successful removal of metalic foreign body from brain and internal carotid artery with a platinum-Cobalt magnet alloy

Two successful removals of metalic foreign body with a platinum-Cobalt magnet alloy (Pt-Co magnet) which has a size of 4×4 mm and is capable of lifting 120 g of weight were reported, one a metal fragment from the brain via a inlet track, and the other a needle from the internal carotid artery. A metal piece of motorcycle was accidentally flew in which was demonstrated by X-ray examination of the skull. Pt-Co magnet was inserted into the entrance hole on the right eyebrow under fluoroscopic control. The metal fragment of 20×4×1 mm size was pulled out with minimal damage to the surrounding brain tissues. The other was the accidental breakage of a needle tip during carotid angiography. A needle tip remained in the internal carotid artery at cranial base was successfully removed with a Pt-Co magnet inserted through the previous injection site.