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Background/Purpose: Viral infections and innate immunity signaling, especially Toll-like receptor 7 (TLR7) have been implicated in the pathogenesis of biliary atresia (BA). Administration of rhesus rotavirus-type A to newborn Balb/c mice produces inflammatory obstruction of bile ducts, which resembles human BA. However, whether activation of TLR7 signaling plays a role in neonatal hepatobiliary injury remains to be investigated. Methods: TLR7 agonist, imiquimod (R837), was intraperitoneally administered to Balb/c mice within 24 hours of birth and then every other day. Morphological and histological injuries of liver and gallbladder were examined at 2 weeks. Hepatic messenger RNA expression of TLR7 signaling was studied. Terminal deoxynucleotidyl transferase 2′-deoxyuridine 5′-triphosphate nick end labeling staining was used to delineate hepatobiliary apoptosis upon TLR7 stimulation. Results: TLR7 agonist, imiquimod, induced hypoplasia of the biliary system of neonatal Balb/c mice both in atrophic gallbladder and in paucity of intrahepatic bile ducts. There was significantly higher hepatic expression of TLR7 and downstream innate immunity-mediated interferon regulatory factor 7, interferon-α, and tumor necrosis factor-α. In addition, terminal deoxynucleotidyl transferase 2′-deoxyuridine 5′-triphosphate nick end labeling-positive cells in the liver were increased after injections of TLR7 agonist. Conclusion: The results demonstrate that TLR7 activation may trigger innate immunity pathways and induce apoptosis and hypoplasia of neonatal biliary trees in Balb/c mice. The novel findings give an implication of pathogenesis of infantile cholestasis, such as BA. Keywords: animal model, Balb/c mice, biliary atresia, infantile cholestasis, innate immunity, toll-like receptor 7

To study the influence of clinical audit on diagnosis, complications, and factors contributing to hospitalization of patients with infantile hypertrophic pyloric stenosis. Study Design: Retrospective cohort study. Method: There were 214 patients from 1991 to 2004 from three medical centers in Kaohsiung. Data were analyzed with respect to diagnostic methods, complications, and factors requiring patient hospitalization. Results: The ratio of male to female was 4.8:1 (177 males and 37 females). The diagnoses before admission were as follows: 22% had milk intolerance and 14.5% had esophageal reflux. There was a significant increase in the use of sonogram diagnostic test (p=0.005) and a decrease in the incidence of diagnosis by olive mass palpation but not by barium meal test. Surgery time of 48 hours after admission was significant with barium meal examination and related to longer hospital stay (p