Influence of granulocytopenia on canine cerebral ischemia induced by air embolism.

We subjected nine dogs with severe granulocytopenia 4 days after the administration of mechlorethamine to 1 hour of cerebral ischemia induced by the controlled, incremental injection of air into the internal carotid artery. Cortical somatosensory evoked responses and cerebral blood flow determined by [14C]iodoantipyrine autoradiography were compared with those of six control dogs that had received mechlorethamine 1 day previously and were not yet granulocytopenic. Eleven additional control dogs received no mechlorethamine but had identical ischemic insults and were followed for 4 hours after ischemia. Both control groups had identical evoked response outcomes after 1 hour of recovery from ischemia. Granulocytopenic dogs had improved evoked response recoveries compared with either control group after 1 hour of recovery. No areas of very low blood flow were observed 1 hour after ischemia in the granulocytopenic dogs, but three of five dogs in the control group receiving mechlorethamine had such areas.