Clinical characteristics and predisposing factors for complication of caustic injury of the upper digestive tract / 대한내과학회지

BACKGROUND: Accidental or suicidal ingestion of caustic agents is not uncommon. The caustic injury of upper digestive tract can lead to severe stenotic sequelae. We attempt to investigate clinical characteristics, endoscopic findings and predisposing factors of development of complications of caustic injury. METHODS: The medical records of 77 patients admitted to our department for caustic ingestion from March, 1993 to June, 2004 were reviewed. All patients underwent initial endoscopic examinations and caustic lesions were graded according to Zargar's classification (Grade 0~III). RESULTS: Strictures of the esophagus and the stomach occurred in 12 patients (15.6%) and 3 patients (3.9%), respectively. The development of esophageal or gastric stricture was more frequent when the grade of caustic injury of the esophagus or the stomach was more severe. Hemorrhage from exposed vessels of the injured esophagus and stomach was seen in one patient and so was jejunal hemorrhage. Two patients (2.6%) died of multiple-organ failure. All cases of hemorrhage and death resulted from grade III lesions of the esophagus, stomach and duodenum. The type or amount of the caustic agent, duration between ingestion and endoscopic examination, and initial treatment with steroid and/or antibiotics did not correlate with the development of stricture. CONCLUSIONS: Caustic injury of the esophagus and the stomach was significantly associated with esophageal stricture. Early endoscopic examination was very useful for predicting the development of complications and prognosis after caustic injury.

Thyrotropin Suppresses INF-r Mediated Gene Expression by Inhibiting Signal Transducer and Activation of Transcription 1(STAT1) Activity in FRTL-5 Cells / 대한내분비학회지

BACKGROUND: The proinflammatory cytokine, IFN-y has been shown to exert pleiotropic effects in a variety of pathophysiologic conditions in autoimmune thyroid disease. The thyrocyte response to IFN-y is mediated two distinct classes of proteins, Janus kinases(Jakl and Jak2) and Signal Transducers and Activation of Transcription(STATl). The activation of STAT 1 is involved in the regulation of many interferon stimulated genes, such as MHC class II, intercellular adhesion molecules-1(ICAM-1) and MHC class II transactivator(CIITA) after the binding to the GASgFN- pactivated site) of the gene promoters. Recently we found TSH/forskolin inhibits IFN-y stimulated maximal expression of ICAM-1 in FRTL-5 cell. IFN-y action is localized between -175 bp and -97 bp from the start of translation of ICAM-1 gene which contains regulatory elements known to be involved in IFN-y action in other eukaryotic cells, palindromic IFN-y activated site(GAS)(5-TTTCCGGGAAA-3) which could bind STAT1, STAT3, STAT5, STAT6. Furthermore, the addition of TSH and forskolin causes a decrease in ICAM-1 promoter activity and its action was localized in GAS. These findings suggested TSH/cAMP signaling pathways downregulate IFN-y activated Janus kinase-STAT signaling path. We wanted to explore the possible involvement of elevated cAMP in the negative regulation of IFN-y induced STAT1 activation in thyroid cells. METHOD: We made several 5-deletion constructs of rat ICAM-1 promoter and analyzed the promoter activities by measuring the luciferase activity after tranfection into FRTL-5 cells. The protein/DNA complex was measured by electrophoretic mobility shift analysis using labeled oligonucleotide. We checked the level of total and phosphorylated STATl protein by immunoblot analysis using specific antibodies. RESULTS: Stimulation of IFN-y in FRTL-5 cells resulted in rapid activation of STATl/DNA binding activity, which was apparent after several minute of stimulation, maintains its activity until 48 h. Incubation of cells with TSH result in suppression of IFN-p mediated STAT1/DNA binding activity throughout the time course of activation by IFN-y. Addition of TSH into 5H maintained FRTL-5 cells did not change the total amount of latent STAT1 amount and also not affect IFN-y mediated production of total STAT1 until 4 h. IFN-y(100 U/mL) rapidly induced phosphorylation of STAT1 within 30 min. and maintained its level without significant change until 48 hours. Cells treated with TSH dramatically lowered the level of IFN-y induced production and phosphorylation of STAT1 after 12 h, 24 h, 36 h, and 48 h but TSH had no effect on the level of phosphorylated STATl within 4 h after IFN-y stimulation. The proteasome inhibitor, MG132 and phosphatase inhibitor, sodium orthovanadate did not block the TSH or forskolin mediated downregulation of phosphorylated STAT1. CONCLUSION: These results indicate a regulatory mechanism which TSH signaling can modulate the prolonged activation of Jak/Stat by IFN-y. We identified one of mechanisms related to TSH mediated negative suppression of the ICAM-1 gene; TSH/cAMP signaling pathways downregulate the cytokine activated Janus kinase-STAT signaling path.