The sural nerve of a 31-year-old man with Lesch-Nyhan syndrome obtained at autopsy was studied histologically. Large, myelinated nerve fibers were reduced in number and no myelinated nerve fibers larger than 5 microns were seen. Diameter distribution of myelinated nerve fibers did not demonstrate a bimodal pattern. The density of myelinated nerve fibers was 5,530/mm2 and was decreased as compared to the controls. On electron microscopic examination, lipid-like inclusions were observed in the cytoplasm of some Schwann cells. The role of these inclusions could not be elucidated, but reduction of larger myelinated nerve fibers suggests a peripheral nervous disorder in patients with this syndrome; therefore, patients with Lesch-Nyhan syndrome must be reappraised for disorders of the peripheral nervous system.

Adult↗

PubMedDate not supplied

The restraint stress-induced elevation in plasma interleukin-6 negatively regulates the plasma TNF-alpha level.

Although a considerable amount of evidence has shown that physical and psychological stress elevates the plasma interleukin 6 (IL-6) levels, the physiological significance of such an elevation remains to be elucidated. In this study, in order to determine whether the restraint stress-induced elevation of plasma IL-6 contributes to the activation of the hypothalamic-pituitary-adrenal axis, and whether or not such elevation can affect the inflammatory processes, the plasma levels of ACTH, corticosterone, interleukin-1 (IL-1), and tumor necrosis factor-alpha (TNF-alpha) in mice pretreated with anti-IL-6 antibody (MP5-20F3 monoclonal antibody) were compared with those in mice pretreated with rat IgG (control antibody) both during and after stress. Both the anti-IL-6-antibody- and control-antibody-pretreated mice showed the same extent of plasma ACTH and corticosterone increases during stress, and no significant difference was found between the two groups of animals. On the other hand, the level of plasma TNF-alpha in the anti-IL-6-treated animals was also significantly higher than that in the control animals both immediately after cessation of stress and 60 min after the cessation of the 120-min period of restraint. Plasma IL-1 activity, however, did not reach a detectable level in either group of animals at any time point examined. These results thus indicate that the restraint-stress-induced elevation of plasma IL-6 negatively regulates the plasma TNF-alpha levels and may thus contribute to the maintenance of homeostasis.

Adrenocorticotropic Hormone↗