Molecular therapeutics of HBV.

The hepatitis B virus (HBV) infection is a public health problem worldwide, particularly in East Asia. The current therapy of HBV infection is mostly based on chemical agents and cytokines that have been shown to provide limited efficacy and are also toxic to the human body. Gene therapy is a new therapeutic strategy against HBV infection, involving the transmission of gene drugs into liver cells by specific delivery systems and methods. Although this new anti-HBV infection technique is under active investigation, various promising anti-HBV viral gene drugs have been developed for gene therapy, including antisense RNA and DNA, hammerhead ribozymes, dominant negative HBV core mutants, single chain antibody, co-nuclease fusion protein, and antigen. In order to optimize their antiviral effects and/or enhance anti-HBV immunity, various novel gene delivery systems have also been developed to (specifically) deliver such DNA constructs into liver cells; some of them are viral vectors, such as adenoviral vectors, retroviral vectors and poxviral vectors, and even hepatitis B viral for its hepatocellular specificity. Others are non-viral vectors, in which naked DNA and liposomes are frequently used for DNA vaccine or nucleotide analogs for inhibiting HBV DNA polymerase. This review addresses various aspects of gene therapy for HBV infection, including gene drugs, delivery methods, animal model, and liver transplantation with combination therapy. It also discusses the problems that remain to be solved.

MRI of late microstructural and metabolic alterations in radiation-induced brain injuries.

PURPOSE: To evaluate the late effects of radiation-induced damages in the rat brain by means of in vivo multiparametric MRI. MATERIALS AND METHODS: The right hemibrains of seven Sprague-Dawley rats were irradiated with a highly collimated 6 MV photon beam at a single dose of approximately 28 Gy. Diffusion tensor imaging (DTI), proton MR spectroscopy ((1)H-MRS), T2-weighted imaging, and T1-weighted imaging were performed to the same animals 12 months after radiation treatment. RESULTS: Compared with the contralateral side, a significantly higher percentage decrease in fractional anisotropy was observed in the ipsilateral fimbria of hippocampus (29%) than the external capsule (8%) in DTI, indicating the selective vulnerability of fimbria to radiation treatment. Furthermore, in (1)H-MRS, significantly higher choline, glutamate, lactate, and taurine peaks by 24%, 25%, 87%, and 58%, respectively, were observed relative to creatine in the ipsilateral brain. Postmortem histology confirmed these white matter degradations as well as glial fibrillary acidic protein and glutamine synthetase immunoreactivity increase in the ipsilateral brain. CONCLUSION: The microstructural and metabolic changes in late radiation-induced brain injuries were documented in vivo. These multiparametric MRI measurements may help understand the white matter changes and neurotoxicity upon radiation treatment in a single setting.

Early detection of neurodegeneration in brain ischemia by manganese-enhanced MRI.

This study aims to employ in vivo manganese-enhanced MRI (MEMRI) to detect neurodegenerative changes in two models of brain ischemia, photothrombotic cortical injury (PCI) and transient middle cerebral artery occlusion (MCAO) in rodents. After systemic Mn(2+) injection to both ischemic models, a close pattern of T1-weighted hyperintensity was observed throughout different brain regions in comparison to the distribution of GFAP, MnSOD and GS immunoreactivities, whereby conventional MRI could hardly detect such. In addition, the infarct volumes in the posterior parts of the brain had significantly reduced after Mn(2+) injection to the MCAO model. It is suggested that exogenous Mn(2+) injection may provide enhanced MEMRI detection of oxidative stress and gliosis early after brain ischemia. Manganese may also mediate infarctions at remote brain regions in transient focal cerebral ischemia before delayed secondary damage takes place.

[Apoptosis of human gastric cancer cell induced by photochemical riboflavin].

BACKGROUND & OBJECTIVE: Photochemical riboflavin, the production of reactive oxygen species (ROS), has been reported having cytotoxity on some cancer cells. The aim of this study was to investigate the effect of photochemical riboflavin on inducing apoptosis in human gastric cancer cell line MGC80-3. METHODS: Trypan blue exclusion method, Giemsa staining, DNA electrophoresis, DNA quantification, Western blot analysis, and flow cytometry were conducted to determine the effect of photochemical riboflavin on cell survival, morphology, DNA fragmentation, gene expression, and cell cycle arresting. RESULTS: The cell viability dropped down according to the riboflavin concentration and treating time. Exposure of the cells in 20 micromol/L riboflavin for 24 hours resulted in typical apoptotic morphology and G(2)/M arresting. As MGC80-3 cells were separately treated with 10, 20, 30, and 40 micromol/L photochemical riboflavin, DNA electrophoresis showed that the ladder bands, a typical feature of apoptotic cell, appeared in the groups treated by over 20 micromol/L photochemical riboflavin. The efficiency rates of DNA fragmentation were 35.4%, 54.1%, 70.6%, and 86.8%, respectively. Western blot analysis showed that the expression of apoptosis related proteins p53, C-myc, and Bax were up-regulated whereas the expression of Bcl-2 was down-regulated. CONCLUSION: These results indicate that photochemical riboflavin has high efficiency of inducing cell apoptosis on MGC 80-3 cells in vitro and there is a correlation between apoptosis and G(2)/M arresting.