Role of oxygen radicals in ischemia-induced lesions in the cat stomach

Ischemia in a stomach that contains acid may produce severe gastric mucosal injury. The extent to which oxygen-derived free radicals are involved in the pathogenesis of this injury was investigated in the present study. Local gastric ischemia was achieved by reducing celiac artery pressure to 30 mmHg for 1 h. Ischemic injury was assessed by recording the loss of 125I-albumin and 51Cr-red cells across the gastric mucosa. Cats were treated with a xanthine oxidase inhibitor (allopurinol), a superoxide radical scavenging enzyme (superoxide dismutase), and a scavenger of hydroxyl radicals (dimethyl sulfoxide). The damage associated with ischemia only occurred during reperfusion of the stomach and was worst in the antrum. The level of xanthine oxidase in the antrum was twice that of the corpus. Treatment with allopurinol, superoxide dismutase, and dimethyl sulfoxide reduced 51Cr-red cell loss to 15%, 25%, and 21% of control (untreated) animals, respectively. The data indicate that oxygen-derived free radicals play a role in ischemic injury to the stomach and that the hydroxyl radical, a secondary radical produced from the superoxide anion, appears to be the major oxygen radical contributing to ischemic damage.

Immunohistochemical localization of GABAergic cells in the developing human dorsal lateral geniculate nucleus

GABAergic neurons were demonstrated in the dorsal lateral geniculate nucleus (dLGN) of human foetuses of 21 weeks gestation using unlabelled antibodies against gamma-aminobutyric acid (GABA). These inhibitory neurons are thus cytochemically identifiable prior to appearance of lamination, at a period when there is reportedly segregation of retinal afferents from both eyes and formation of morphologically defined synapses. Their presence in the prenatal period indicates that the morphological substrate responsible, in part, for the orientation sensitivity of the dLGN neurons exists before birth in man.

Superior sagittal sinus thrombosis after closed head injury

A case of superior sagittal sinus thrombosis after a closed head injury is presented along with a review of 11 other reported cases. Review of the literature indicates that this condition is rarely recognized and that further investigation is necessary to define the incidence, prognostic factors, and optimal therapy of this condition.