Effect of niridazole and niridazole immunoregulatory factor (NIF) on cutaneous delayed hypersensitivity in mice

It has been suggested that the suppression of cell-mediated immune phenomena following niridazole administration is most likely due to a niridazole metabolite rather than the parent drug. This hypothesis was tested using two inbred strains of mice that manifest different rates of microsomal niridazole oxidation and reduction. DBA/2J mice were found to metabolize niridazole at a rate approximately 3-fold greater than C57BL/6J mice under both aerobic and anaerobic conditions. Niridazole was found to be more potent with respect to suppression of cutaneous delayed hypersensitivity in the former than in the latter. An immunosuppressive component was isolated from the urine fraction obtained from niridazole-treated rats. This component was found to be chromatographically pure; have a simple UV absorbance spectrum containing no 360 nm absorbing material characteristic of niridazole; to show no strain difference with respect to potency or efficacy in the ear-swelling assay for cutaneous delayed hypersensitivity; and to be 10(7) times more potent than niridazole with respect to the suppression of cutaneous delayed hypersensitivity.     

Remodelling of optic nerve myelin sheaths and axons during metamorphosis in Xenopus laevis

Whole mounts and transverse sections of Xenopus optic nerves were examined with the light and electron microscopes before, during, and after metamorphosis. In stage 52-58 tadpoles, almost all myelin sheaths were circular in transverse sections. Early in metamorphosis (stages 60-61) large redundant myelin loops surrounded many large axons in central regions of the nerve. The loops subsequently were broken down into ovoids and lamellar segments that remained mostly within oligodendrocytes. These myelin changes were not observed in the chiasm or next to the eye. They were not associated with significant axonal degeneration and were no longer apparent in optic nerves of young frogs. Xenopus optic nerves also became shorter during metalmorphosis. We therefore suggest that myelin sheaths with redundant loops which degenerate and disappear are being remodelled as the nerve decreases in length.     

Plastic surgical education for the otolaryngologist

Otolaryngology shares responsibility for provision of plastic surgical services involving facial and cervical structures, but many training programs have been weak in this part of the specialty. Some still are. Beginning in 1963 when a national organization was formed, leading facial plastic surgeons and the senior author analyzed the weaknesses and embarked on a program to correct these educational deficits. There was widespread lack of surgical background, woefully inadequate knowledge of soft tissue techniques, and poor understanding of dynamics involved in cosmetic procedures. Annual meetings, international symposia, numerous courses, and extensive videotape and microfiche production, as well as political and academic recognition, have all helped plastic surgical teaching endeavors at both residency and postgraduate levels. However, much remains to be done. Program directors are the “key” people here. Suggestions for future action are presented.