The hepatitis B virus-X protein (HBx) regulates fundamental aspects of mitochondrial physiology. We show that HBx down-regulates mitochondrial enzymes involved in electron transport in oxidative phosphorylation (complexes I, III, IV, and V) and sensitizes the mitochondrial membrane potential in a hepatoma cell line. HBx also increases the level of mitochondrial reactive oxygen species and lipid peroxide production. HBx does not activate apoptotic signaling, although it sensitizes hepatoma cells to apoptotic signaling, which is dependent on reactive oxygen species. Increased intrahepatic lipid peroxidation in HBx transgenic mice demonstrated that oxidative injury occurs as a direct result of HBx expression. Therefore, we conclude that mitochondrial dysfunction is a crucial pathophysiological factor in HBx-expressing hepatoma cells and provides an experimental rationale in the investigation of mitochondrial function in rapidly renewed tissues, as in hepatocellular carcinomas.

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Stroke is the most common cause of death as single-diseases in South Korea. And it generates additional medical cost through high incidence of related disabilities and complications, which would become more important with the rapid aging process in Korean society. This study was preformed to identify stroke patients' mortality and its associated factors. Patients diagnosed as stroke (ICD-10 code I60-I63) in 2003 were identified. Their follow-up mortality rate in 5 years and related factors (stroke type, sex, age, type of first admission hospital, comorbidity score) were analyzed using national health insurance claim data and national cause of death statistics. The mortality rate peaked in early days after attack, and decreased subsequently as the survive time gets longer. The mortality rate was higher in hemorrhagic stroke than ischemic stroke, in female than male, with the older age, and with the higher comorbidity score. It is recommended that the early intervention at general hospital or tertiary referral hospital should be promoted to decrease the mortality rate in stroke patients, and related quality assurance programs have to be enforced.