To identify and describe neurons in neostriatal transplants that synthesize acetylcholinesterase (AChE), the present study has utilized the irreversible AChE inhibitor diisopropylfluorophosphate (DFP) combined with AChE histochemistry. Dissociated suspensions of tissue taken from the striatal ridge of embryos at 14 days of gestation were transplanted into the neostriatum of adult rats 5 days after intrastriatal kainic acid lesions. Two types of AChE neurons have been identified in transplants treated with DFP. One type resembled the large intensely reactive AChE neuron that is thought to be a cholinergic interneuron of the normal neostriatum. The other type resembled smaller, less reactive AChE neurons of the neostriatum, as well as medium-sized, lightly reactive AChE neurons of the globus pallidus. Qualitative observations suggest that these less reactive AChE neurons were more numerous in transplants compared to the normal neostriatum. Both AChE neuronal types were found in segregated clusters throughout the grafts. Transplants processed for AChE histochemistry without DFP treatment contained two types of AChE neuropil. Dark areas of AChE neuropil similar in intensity to the normal neostriatum were found between larger areas of lighter AChE neuropil. These results demonstrate that neostriatal transplants contain AChE neurons and suggest that these neurons contribute to the AChE reactivity within the graft.

Contralateral hearing loss is a very rare complication of acoustic neuroma surgery. A case of immediate postoperative contralateral hearing loss is reported. Possible causes and the pertinent literature are reviewed.

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The present study was designed to determine the selected monoamine changes that occur during infantile hydrocephalus. Obstructive hydrocephalus was induced in newborn rats by injection of a suspension of kaolin into the 4th ventricle and cisterna magna. Eleven days later, experimental animals and their sham-operated littermate controls were killed and pieces of frontoparietal cortex, neostriatum, cerebellar vermis, and brain stem were processed for high performance liquid chromatography. Grossly, the lateral ventricles were extremely enlarged, the cerebral cortex was thinned, the neostriatum was compressed, and portions of the tectum and cerebellum were vacuolated. Decreases in norepinephrine (71%), dopamine (73%), and serotonin (50%) were observed in the cerebral cortex, neostriatum, and cerebellum, respectively. Brain stem norepinephrine and serotonin were increased 70% and 50%, respectively. These increases may indicate impairment of axonal transport or damage to projections from the locus ceruleus and raphe region. These preliminary results suggest that infantile hydrocephalus causes perturbations in the levels of different monoamines in several brain regions. Such changes may critically influence neuronal function and development, as well as the therapeutic management of hydrocephalus.

The unusual concurrence of a brain tumor and an arteriovenous malformation (AVM) is discussed in this case report. A 12-year-old child presented with a severe headache, and an intracerebral mass was found on neuroradiological study. At operation, we encountered a superficial AVM, not shown on the computed tomogram or arteriogram. At a second procedure, a ganglioneuroma was removed. The literature on the concurrence of these two entities is reviewed; comments are made on the pathology of ganglion cell tumors.