Oxidant stress responses in influenza virus pneumonia: gene expression and transcription factor activation.

The pathogenesis of influenza virus infections of the lungs is in part mediated by oxidative stress. Such infections might therefore be expected to induce expression of stress-response genes and genes encoding antioxidant enzymes and to activate transcriptional regulatory proteins. Mice (C57B1/6 and C3H/HeJ) were infected intranasally with influenza virus A/PR/8/34 (H1N1). Expression of the genes encoding the antioxidant enzymes manganese superoxide dismutase (Mn- SOD), indoleamine-2, 3-dioxygenase (IDO), heme oxygenase-1, and glutathione peroxidase were increased in the lungs of virus-infected animals. Cu/ZnSOD and catalase mRNA were not induced by viral infection. Activation of the transcriptional regulatory proteins AP-1, C/EBP, and NF-kappa B (which are known to be affected by oxidant stress) was demonstrated by electrophoretic mobility shift assay after viral infection. In the case of MnSOD, despite increased gene expression enzyme activity was not increased. In contrast, for heme oxygenase-1 both mRNA and activity were increased. C3H/ HeJ and C57B1/6 mice, which are known to have different responses to other types of oxidant stress, also differed in their responses to viral infection. Induction of heme oxygenase-1 expression was greater in C57B1/6 mice than in C3H/ HeJ mice, although inhibiting this enzyme did not alter virus-induced mortality. In contrast, IDO was more strongly induced in C3H/HeJ mice. Activation of NF-kappa B was much more marked in C57B1/6 mice than in C3H/HeJ mice. Although virus replication and inflammatory responses were equivalent in the two strains, lung injury (as measured by wet-to-dry wt ratios) and mortality were greater in C3H/HeJ mice than in C57B1/6 mice, a difference that may be related to differing oxidant stress responses. Thus influenza pneumonia causes an oxidant stress response in the lungs, the nature of which is determined in part by the genetic background of the host.

Hemorrhoidal bleeding in chronic spinal cord injury: results of multiple banding.

Most patients with chronic spinal cord injury (SCI) have hemorrhoidal bleeding. 87 banding procedures were performed for bleeding on 62 men with chronic SCI. Multiple bands per session were routinely necessary. Bleeding sites at or distal to the dentate line were also banded. There were no major complications. An outcome questionnaire was completed by 60 subjects (97%). Mean follow-up was one year, minimum one-half year. 73% of patients reported significant reduction in bleeding post-banding, and 20% reported some reduction. A majority of patients felt the procedure was useful or worthwhile overall. Absent sensation allows banding of external hemorrhoids, although symptoms of autonomic hyper-reflexia may occur in patients with lesions at T6 or above. Multiple banding is a safe and effective treatment for hemorrhoidal bleeding in SCI.