Methods: The bicistronic reporter constructs, termed pSV40-HM175-IRES, pSV40-A1-IRES, pSV40-A2-IRES, pSV40-F1-IRES, and pSV40-F2-IRES, contain the SV40 promoter that controls the expression of a bicistronic message coding for renilla and firefly luciferases separated by HAV IRES, and are derived from strain HM175, acute convalescent hepatitis clones A1, A2, fulminant hepatitis clones F1, F2, respectively. Human hepatoma cell lines were co-transfected with pSV40-HAV-IRES and each HAV protein-expression vector. Luciferase activity was determined 48 h after transfection. were from other countries within Asia, Africa, Middle East, and Eastern Europe. Patients of a wide age range were affected by hepatitis delta (mean age 46.0, median 47.0, range 19-79). 18 (40%) of 45 were co-infected with HCV. Hepatitis B virus (HBV) DNA was detectable in 43 (78%) patients and negative in 8 (15%) patients. All hepatitis delta patients were extracted from a prior study conducted by this collaboration. There were 1,191 chronic HBV carriers. 18 (1.51%) were HBV/ HCV/HDV infected. 32 (58%) of 55 patients carried a diagnosis of cirrhosis compared to 262 (22%) of 1191 chronic HBV patients. 13 (72%) HCV co-infected patients had evidence of cirrhosis while 4 (22%) patients did not. Conclusion: Individuals with HBV/HDV co-infection have higher rates of cirrhosis. Individuals with HBV/HCV/HDV infection have rates of cirrhosis significantly higher than individuals with either chronic HBV infection or HBV/HDV co-infection. Testing for HDV should be performed in all patients, especially those with advanced liver disease or high risk behavior. Clinical characteristics were compared between the patients with significant endoscopic findings (group A) and without such findings (group B). Peak AST and ALT level were higher in group A (p<0.01). There were no statistical differences in age, gender, comorbidity, and etiology of acute hepatitis between group A and group B Conclusion: Significant endoscopic findings were found in considerable proportion of patients with acute hepatitis. Severity of acute liver injury was associated with significant upper gastrointestinal endoscopic findings. In patients with severe acute hepatitis who complain of upper gastrointestinal symptom, esophago-gastro-duoenoscopy should be performed. Background: In Japan, hepatitis E virus (HEV) testing is not allowed as routine one. To study the role of HEV testing, we checked 22 sera of the patients diagnosed as etiology-obscure acute liver injury. Methods: We have seen 54 cases of acute liver injury from January 2004 through December 2007 in our hospital and 25 cases of them were etiology-obscure. In 25 cases, 22 were retrospectively tested for HEV-IgM, HEV-IgA and HEV-RNA (RT-PCR) by direct sequence method on stored sera taken at the time of presentation. Result: Two of 22 cases (9.1 ) were positive for both HEV-IgM and HEV-IgA and one case was positive for HEV-RNA. In 54 cases of acute liver injury, the cause of virus was 31 cases (57.4%) and unknown was 8 cases (14.8%). HEV was occupied in 3.7% in all cases and 6.5% in the cases caused by virus. One of the two cases had been misdiagnosed as "drug induced hepatitis". HEV of genotype 3 was detected in one case and its nucleotide sequences of HEV showed quite a high degree of similarity to the reported one at closed city in the same year. Conclusion: HEV is not rare in Japan and the HEV testing can reverse the diagnosis of acute liver injury. HEV testing sould be used as routine one for acute liver injury.