Biomedical subjects

Tian Xiao

Publications and source records attributed to Tian Xiao.

4 recordsLinked to original sources

PubMed2006

Isolation and characterization of novel marine Roseobacter clade members producing unique intracellular chromium-rich aggregates.

The marine Roseobacter clade comprises one of the largest fractions of heterotrophic marine bacteria and accounts for about 16% of 16S rRNA gene clones retrieved from marine bacterioplankton. Their global distribution seems to be related to oceanic water masses and their environmental and biogeochemical properties. In this study, we report isolation and characterization of novel Roseobacter clade members from the Yellow Sea, China. Phylogenetic analysis of 16S rRNA gene sequences reveals that the new isolates (YSCB1, YSCB2, YSCB3 and YSCB4) are closely related to uncultured Arctic seawater bacterium R7967 (99.57-100% sequence identity) and to the cultured Roseobacter sp. DSS-1 (99.27-99.76% sequence identity) isolated from the southeastern coastal water of the USA. Interestingly, YSCB strains possess unique intracellular chromium-containing aggregates. Therefore, these novel Roseobacter clade members exhibit a peculiar property in mineral biogeneration.

Chromium↗

PubMed2006

Adenoviral vector expressing CYLD augments antitumor activity of TRAIL by suppression of NF-kappaB survival signaling in hepatocellular carcinoma.

UNLABELLED: CYLD is a tumor suppressor gene related to cylindroma and is negative regulator of NF-kappaB. However, antitumor effect of CYLD has not been reported. The activation of NF-kappaB induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) renders hepatocellular carcinoma (HCC) resistant to TRAIL-mediated cell apoptosis. Here we described that the adenoviral vector expressing CYLD (Ad/hTERT-CYLD) augmented the cytotoxicity of TRAIL in HCC cells by negatively regulating NF-kappaB activity since CYLD could reverse the ubiquitination of TNF receptor-associated factor 2 (TRAF2) and interact with the IkappaB kinasegamma (IKKgamma). The combined treatment of Ad/hTERT-CYLD and a conditionally replicating adenovirus carrying TRAIL gene (ZD55-TRAIL) induced rapid and potent apoptosis in HCC cells, characterized by activation of caspase-3, caspase-8, PARP and the reduction of X-linked inhibitor of apoptosis protein (XIAP). In animal study, the combined treatment could eradicate the BEL7404 xenograft tumors. In contrast, treatment with Ad/hTERT-CYLD or ZD55-TRAIL alone achieved less antitumor effect. IN CONCLUSION: CYLD inhibits TRAIL-mediated NF-kappaB activation and enhances the sensitivity of HCC cells to TRAIL-triggered apoptosis. The combined delivery of Ad/hTERT-CYLD and ZD55-TRAIL may be a new useful strategy for HCC or other tumor cells with enhanced NF-kappaB activity.

Adenoviridae↗

PubMed2006

[Security of dual cancer-specific targeting vector and its cytotoxic effect when harbored].

BACKGROUND & OBJECTIVE: The xenograft tumor mass in nude mice could be completely eliminated using the targeting dual gene-virotherapy strategy. Now, the most important point is to improve its security. This study was to construct dual cancer-specific targeting adenovirus called TD55 to evaluate its security, and construct TD55-TRAIL to explore its antitumor effect. METHODS: Plasmid pTD55 was constructed through replacing E1A promoter with promoter of human telomerase reverse transcriptase and deleting E1B 55KD gene, and plasmid pTD55-TRAIL was constructed by inserting TRAIL gene into pTD55. Adenoviruses TD55 and TD55-TRAIL were obtained through homologous recombination in 293 cells. Cytotoxic effects of TD55 and TD55-TRAIL on human colon cancer cell lines SW620 and HCT116, human lung cancer cell line A549, and human embryonic lung cell lines MRC5 and WI38 were detected by crystal violet staining and MTT assay. Tumor cell apoptosis was detected by flow cytometry. RESULTS: Cytotoxic effects of TD55-TRAIL on MRC5 and WI38 cells were weaker than those of ZD55-TRAIL. The virus proliferation ability of ZD55-TRAIL in normal cells is 3-5 times stronger than those of TD55 and TD55-TRAIL. The apoptosis rate of TD55-TRAIL-infected SW620 cells was 3.3 times as high as that of TD55-infected SW620 cells. CONCLUSIONS: TD55-TRAIL has better security than ZD55-TRAIL in normal cells. So, the security of medication will be improved with dual targeting vector TD55. TD55-harbored gene as TD55-TRAIL has stronger effect than TD55 in inducing apoptosis of tumor cells.

Adenoviridae↗

PubMed2003

Finite difference computation of head-related transfer function for human hearing.

Modeling the head-related transfer function (HRTF) is a key to many applications in spatial audio. To understand and predict the effects of head geometry and the surrounding environment on the HRTF, a three-dimensional finite-difference time domain model (3D FDTD) has been developed to simulate acoustic wave interaction with a human head. A perfectly matched layer (PML) is used to absorb outgoing waves at the truncated boundary of an unbounded medium. An external source is utilized to reduce the computational domain size through the scattered-field/total-field formulation. This numerical model has been validated by analytical solutions for a spherical head model. The 3D FDTD code is then used as a computational tool to predict the HRTF for various scenarios. In particular, a simplified spherical head model is compared to a realistic head model up to about 7 kHz. The HRTF is also computed for a realistic head model in the presence of a wall. It is demonstrated that this 3D FDTD model can be a useful tool for spatial audio applications.

Algorithms↗