Pathologic features in steroid and nonsteroid associated osteonecrosis.

Multiple pathophysiologies for osteonecrosis have been postulated and various associated risk factors defined for this disease. However, the pathologic findings of the end stage disease are thought to be similar in all patients. To the author's knowledge, there are no data in the literature comparing the pathologic characteristics of osteonecrosis in a quantitative manner between groups of patients with different associated risk factors.

Effects of gonadal sex steroids on sexual behavior in the big brown bat, Eptesicus fuscus, upon arousal from hibernation.

Vespertilionid bats are thought to have a dissociated pattern of reproduction; mating occurs in autumn as well as during periodic arousals from hibernation when testes are regressed and ovaries are "in stasis." Sex steroid levels in both sexes are basal at this time. This pattern would indicate that sex steroids per se may not be activating sexual behavior.