Characterization of the expression of inducible nitric oxide synthase in rat and human liver during hemorrhagic shock.

It has been previously shown that the inducible nitric oxide (NO) synthase (iNOS; NOS-2) is elevated after hemorrhage, and that iNOS-derived NO participates in the upregulation of inflammation as well as lung and liver injury postresuscitation from shock. The purpose of this study was to elucidate the time course of iNOS mRNA expression, as well as the cellular and subcellular localization of iNOS protein in the liver posthemorrhage in rats subjected to varying durations of hemorrhagic shock (HS; mean arterial blood pressure [MAP] = 40 mmHg) with or without resuscitation. Expression of iNOS mRNA in rat liver by real-time reverse transcriptase (RT)-PCR demonstrated iNOS upregulation in shocked animals as compared with their sham counterparts as early as 60 min after the initiation of hemorrhage. By 1 h of HS, iNOS protein was detectable in rat liver by immunofluorescence, and this expression increased with time. Immunofluorescence localized iNOS primarily to the hepatocytes, and in particular to hepatocytes in the centrilobular regions. This analysis, confirmed by immunoelectron microscopy, revealed that iNOS colocalizes with catalase, a peroxisomal marker. Furthermore, we determined that iNOS mRNA is detectable by RT-PCR in liver biopsies from human subjects with HS (MAP < 90 mmHg) associated with trauma (n = 18). In contrast, none of the seven nontrauma surgical patients studied had detectable iNOS mRNA in their livers. Collectively, these results suggest that hepatic iNOS expression, associated with peroxisomal localization, is an early molecular response to HS in experimental animals and possibly in human patients with trauma with HS.

Efficacy and complications of argon plasma coagulation for hematochezia related to radiation proctopathy.

BACKGROUND: Endoscopic treatments effectively control bleeding caused by radiation proctopathy. The aims of this study were to determine the efficacy and side effects of argon plasma coagulation in the treatment of this type of bleeding. METHODS: Records of 21 consecutive patients in whom argon plasma coagulation was used to treat hemorrhagic radiation proctopathy were reviewed. RESULTS: Pharmacologic measures had been unsuccessful in 12 patients. Endoscopic treatment had been unsuccessful in 5 patients. All patients were anemic and 4 had received blood transfusions. The mean number of treatment sessions was 1.7, and 10 patients were successfully treated in single session. Rectal bleeding resolved within 1 month of the last treatment in 19 patients, usually on the day of the last procedure. Bleeding resolved 2 months after cessation of therapy in another patient. Short-term side effects occurred in 3 (14%) patients (rectal pain, tenesmus, and/or abdominal distention); long-term complications (rectal pain, tenesmus, diarrhea) developed in 4 patients (19%). CONCLUSIONS: Hematochezia caused by radiation proctopathy is effectively controlled by argon plasma coagulation, in some cases after a single treatment session. Treatment may result in protracted bowel symptoms.