Biomedical subjects

W Bu

Publications and source records attributed to W Bu.

6 recordsLinked to original sources

PubMed2006

Charge inversion at minute electrolyte concentrations.

Anionic dimyristoylphosphatidic acid monolayers spread on LaCl3 solutions reveal strong cation adsorption and a sharp transition to surface overcharging at unexpectedly low bulk salt concentrations. We determine the surface accumulation of La3+ with anomalous x-ray reflectivity and find that La3+ compensates the lipid surface charge by forming a Stern layer with approximately 1 La3+ ion per 3 lipids below a critical bulk concentration, ct approximately 500 nM. Above ct, the surface concentration of La3+ increases to a saturation level with approximately 1 La3+ per lipid, thus implying that the total electric charge of the La3+ exceeds the surface charge. This overcharge is observed at approximately 4 orders of magnitude lower concentration than predicted in ion-ion correlation theories. We suggest that transverse electrostatic correlations between mobile ions and surface charges (interfacial Bjerrum pairing) may contribute to the charge inversion.

Journal Article↗

PubMed2001

Regulation of microtubule assembly by human EB1 family proteins.

The EB1 family proteins are highly conserved microtubule-associated proteins. The EB1 protein in yeast has been shown to play an important role in regulating microtubule dynamics and chromosome segregation. Human EB1 family proteins include EB1, RP1 and EBF3. Although EB1 and RP1 have been shown to associate with microtubules, the subcellular localization of endogenous EBF3 had not been characterized. The function of human EB1 family proteins was also not clear. We therefore investigated the cellular localization of EBF3 and the regulation of microtubule organization by EB1 family proteins. As do EB1 and RP1, EBF3 was found to colocalize with microtubules, preferentially at their plus ends, throughout the cell cycle. Moreover, there was a very strong EBF3 signal at the centrosome in interphase cells and at the spindle poles in mitotic cells. When EB1 family proteins were overexpressed, they associated with the entire microtubule cytoskeleton. In addition, EB1 and EBF3 induced microtubule bundling in some cells overexpressing these proteins. These microtubule bundles were more resistant to nocodazole and were more acetylated than regular microtubules. Our results demonstrate for the first time that human EB1 family proteins could regulate microtubule assembly and stability.

Cell Compartmentation↗

PubMed2001

[Cloning, sequence analysis and high-level expression in Escherichia coli and activity assay of pac-1 gene from Schizosaccharmyces pombe].

The Schizosaccharmyces pombe pac-1 gene product is a kind of dsRNA dependent ribonuclease, which has potential to degrade the dsRNA viral genome, the replication form of ssRNA viral genome and viroid genome. Therefore, to introduce the pac-1 gene into plants conferring them resistance to viruses is a new method of establishing the anti-virus transgenic plant. The pac-1 gene from the S. pmobe genome DNA isolated from China was cloned by means of PCR amplification. The pac-1 gene was inserted into the cloning vector pGEM-7Zf(+) by using restriction endonuclease Kpn I/BamHI. Sequencing analysis shows that it is a complete gene with 1095 necleotides. Compared to the reported pac-1 gene, its homology is significant, but with 5 nucleotides differences, leading to only one amino acid difference. Pac-1 gene was inserted into the prodaryotic expression vector pET-21(a) by using the restriction endonuclase Nde I/BamHI. It was induced by the IPTG in E. coli BL21 harbouring the recombinant vector pET-pac-1. The pac-1 gene product is analyzed by the SDS-PAGE. The result shows the product of pac-1 gene exists in the supernatant part as soluble form and in the precipitant part as inclusion bodies after the cells were lysed by ultrasonic wave. The supernatant was applied to detect the enzyme activity of pac-1 gene product. We concluded that pac-1 gene has the biological activity of degrading the CMV-dsRNA.

Cloning, Molecular↗

PubMed1999

Effect of antiangiogenic agents on experimental animal models of hepatocellular carcinoma.

A new therapeutic strategy for treating metastasis in hepatocellular carcinoma (HCC) has entailed the use of antiangiogenic agents such as suramin, BB-94 (Batimastat), TNP-470, and carboxyamido-triazole (CAI, a synthetic inhibitor of non-excitable calcium channels that reversibly inhibits angiogenesis). These agents have been used to treat metastatic model of HCC in nude mouse (LCI-D20 mouse model). The results of these studies are summarized in this paper with emphasis on the inhibitory effects of the drugs on tumour growth, angiogenesis, invasion and metastasis in LCI-D20 mouse models. The results suggest that all of the agents used can significantly inhibit tumour growth, angiogenesis, invasion and metastasis of human HCC in nude mouse models, and may be candidates for the control of recurrence and metastasis after HCC resection.

Animals↗

PubMed1997

[The role of MMP-2 in the invasion and metastasis of hepatocellular carcinoma (HCC)].

OBJECTIVES: To get insights into the role of MMP-2 in the invasion and metastasis of hepatocellular carcinoma (HCC), and to find a method to judge the invasion and metastasis of HCC through MMP-2. METHODS: Zymograph and immunohistochemistry were used to study the content and types of positive cells of MMP-2 in the HCC, and statistical methods were used to analyse the association between the content of MMP-2 and the pathological indexes of HCC. RESULTS: MMP-2 was expressed by all the normal liver, HCC and surrounding liver parenchyma. The increase of MMP-2 and the presence of the active type of MMP-2 were related to the invasion and metastasis of HCC. The content of MMP-2 in HCC being higher than that in surrounding liver parenchyma was an important index to judge the invasion and metastasis of the HCC. The positive cells of MMP-2 found in immunohistochemistry were normal hepatocytes, cholangioepithelial cells, Ito cells, regenerated hepatocytes, new generated cholangioepithelial cells, and HCC cells. CONCLUSION: MMP-2 was related to the invasion and me astasis of HCC. The content of MMP-2 in HCC being higher than that in surrounding liver parenchyma could be bused as an important index to judge the invasion and metastasis of HCC.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Effects of matrix metalloproteinase inhibitor BB-94 on liver cancer growth and metastasis in a patient-like orthotopic model LCI-D20.

BACKGROUND/AIMS: The aim of this study was to try to understand the effects of the synthetic matrix metalloproteinase inhibitor Batimastat (BB-94) on hepatocellular carcinoma (HCC). METHODOLOGY: An orthotopic metastatic human hepatocellular carcinoma in nude mice model (LCI-D20) was used to study primary tumor growth, local invasion and metastasis of HCC. MTT assay was used to study the effects of BB-94 on cytotoxin and proliferation of HCC cell line SMMC-7721 in vitro. A gelatine zymograph was used to study the expression of MMPs in the LCI-D20 tumor tissue. RESULTS: BB-94 can inhibit primary tumor growth, local invasion, intrahepatic and lung metastasis, as well as prolong survival. BB-94 did not affect the proliferation of HCC cells in vitro. LCI-D20 tumor tissue expresses MMP-2 and MMP-9. CONCLUSIONS: BB-94 has a cytostatic therapeutic effect on HCC.

Animals↗