Faculty Bibliography

The bulbocavernosus reflex and pudendal evoked responses were obtained in a group of control patients and impotent men in an attempt to assess their reliability and objectivity in diagnosing neurogenic erectile dysfunction

The following case report presents a patient with transitional cell carcinoma of the bladder referred to this medical center after carcinomatous meningitis developed. Previously he had undergone surgical resection of the primary lesion and had received cis-platinum chemotherapy for lung metastasis. This unusual presentation of metastatic disease (carcinomatous meningitis) seems to alert the surgical and medical communities to new complications

Prior reports of neuroleptic malignant syndrome (NMS) concerned patients with psychiatric disorders, usually schizophrenia, who were taking dopamine receptor blocking agents. We report the syndrome in a patient with Huntington disease who was treated with dopamine-depleting agents. He had a negative evaluation for malignant hyperthermia (MH), and we suggest that NMS differs from MH. The occurrence of NMS caused by dopamine-depleting agents suggests that anticholinergic properties of phenotiazines are not the only cause. Central dopaminergic systems probably participate in thermoregulation, and dopamine depletion probably plays a pathogenetic role in this syndrome.

A viable population of undifferentiated Schwann cells may be prepared from chronically denervated peripheral nerves. Nerve transection stimulates a sequence of cellular events in distal stumps leading to removal of axons and myelin, and proliferation of Schwann cells. Sealing the ends of nerve stumps prevents reinnervation and leaves daughter Schwann cells residing in longitudinal columns. Schwann cells may be harvested from the endoneurial tissue of the nerve stumps 5-12 weeks after nerve transection. Unlike myelinating cells prepared from intact tissue, where function has been specified by associated axons, Schwann cells obtained from denervated stumps are functionally naive. Their usefulness in analyzing axonal regulation of myelinogenesis and mitosis is therefore suggested.

Chronically denervated rat and rabbit tibial nerve distal stumps were studied 3-58 weeks following nerve transection. Schwann cells, macrophages and possibly fibroblasts participated in myelin removal which was largely complete by seven weeks. Degenerating myelinated and unmyelinated fibres developed respectively into circular and flattened columns of Schwann cell processes each delimited by a basal lamina. Schwann cell columns became encircled by fibroblasts and later by cells of perineurial type, underwent shrinkage with time and eventually were replaced by connective tissue. In another experiment, endoneurial tissue was removed from rabbit tibial nerve stumps seven weeks after transection and transplanted between the corneal stroma of the same animal for 2-6 weeks. In this locus, Schwann cells developed a thickened basal lamina and then underwent necrosis. It was concluded that the maintenance of Schwann cells in bands of Bungner is in part dependent on axonal contact and that failure of reinnervation eventually causes the columns of Schwann cells to disappear.