Biomedical subjects

Dapeng Wei

Publications and source records attributed to Dapeng Wei.

10 recordsLinked to original sources

PubMed2004

Uptake of folate-conjugated albumin nanoparticles to the SKOV3 cells.

The bovine serum albumin nanoparticles (BSANPs) were prepared by a coacervation method and chemical cross-linking with glutaraldehyde. Furthermore, the BSANPs were reacted with the activated folic acid to conjugate folate via amino groups of the BSANPs, to improve their intracellular uptake to target cells. The nanoparticles were apparently spherical with diameters less than 150 nm and their average diameter was 70 nm by a transmission electron microscope (TEM) and a laser light scattering particle analyzer, respectively. An extent of folate conjugation with the BSANPs was 169 micromol/g BSA by spectrophotometric analysis. Cell uptake studies were carried out in SKOV3 cells (human ovarian cancer cell line) using fluorescein isothiocyanate labeled nanoparticles. The extent of BSANPs taken up by the cells was measured with a fluorescence spectrophotometer. The nanoparticles were taken up to the cells and levels of binding and uptake were increased with the time of incubation until 4 h. The levels of folate-conjugated BSANPs were higher than those of BSANPs and saturable. The association of folate-conjugated BSANPs to SKOV3 cells was inhibited by an excess amount of folic acid, suggesting that the binding and/or uptake were mediated by the folate receptor. These results implied that the folate-conjugated BSANPs might be useful as a drug carrier system to deliver drugs into the cells expressing folate receptor.

Cell Line, Tumor↗

PubMed2004

[Preparation of valaciclovir loaded bovine serum albumin nanoparticles surface-modified with glycyrrhizin and its characteristics of targeting to liver].

The valaciclovir was used as the model drug, the bovine serum albumin nanoparticles (BSA-NP) were prepared by desolvation process. Glycyrrhizin (GL) was oxidized by sodium periodate to be conjugated to surface reactive amino groups (SRAG) of the VACV-BSA-NP. Gel filtration method combined with HPLC method verified that GL was covalent coupling to the surface of VACV-BSA-NP with mean 9 GL residues per albumin molecule. The mean diameter of the VACV-BSA-NP-GL was 268 +/- 23 nm, the drug loading was 1.35%, and embedding ratio was 68.76%. The characteristics of release in vitro were in accord with two-phase kinetics. The uptake amount of VACV-BSA-NP-GL by primary cultured rat hepatocytes in vitro was higher, compared to the control-VACV-BSA-NP. 69.89% and 64.82% of the VACV were concentrated in liver at 15 min after i.v. VACV-BSA-NP-GL and VACV-BSA-NP, respectively. There is a significant difference between surface-modified group and control group (P<0.10). VACV-BSA-NP-GL was successfully prepared, which is considered to be a novel drug delivery system for targeting to hepatocytes.

Acyclovir↗

PubMed2003

[Internalization of antibody-targeted immunonanoparticles into human hepatoma cells and its reversal effect on MDR].

OBJECTIVE: To observe if antibody-targeted immunonanoparticles could internalize into sensitive and multidrug resistance (MDR) cells of human hepatoma; and to study if the immunonanoparticles could reverse the MDR. METHODS: Human hepatoma-specific adriamycin-loaded human serum albumin immunonanoparticles (HAb18-ADR-HSA-NP) were incubated with human hepatoma sensitive cell line (SMMC-7721) or MDR cell line (SMMC-7721/MDR+) and the internalization of immunonanoparticles were observed by laser confocus microscopy, scanning electron microscopy and transmission electron microscopy; MTT colorimetric assay was used for assaying in vitro cytotoxicities of HAb18-ADR-HSA-NP to the resistant variant cells. Then based on these data, IC50 value of the immunonanoparticles and RF (Resistant Factor) of MDR cells were calculated. RESULTS: Laser confocus microscopy showed that many fluorescent particles (labeled immunonanoparticles) tightly adsorbed to SMMC-7721 cells and were also seen in cytoplasm of SMMC-7721 cells. When incubated with immunonanoparticles at 37 degrees C, many of immunonanoparticles were visualized in cytoplasm of SMCC-7721 or SMCC-7721/MDR+. These immunonanoparticles-contained cells exhibited damaged ultrastructures and the damage degree depended on incubation time. When the human hepatoma cells were pretreated with HAb18 antibody and incubated with immunonanoparticles, few immunonanoparticles were seen in cytoplasm of the cells, suggesting antibody-specific internalization of the immunonanoparticles. Scanning electron microscopy demonstrated specific binding of the immunonanoparticles to the resistant variant cells. That immunonanoparticles exerted enhanced cytotoxicity to the resistant variant cells was demonstrated by a decrease of RF value of MDR cells, compared with free ADR (4.4 vs. 2.1). CONCLUSION: Human hepatoma-specific adriamycin-loaded human serum albumin immunonanoparticles could specifically internalize into sensitive or multidrug resistance cells of human hepatoma via antibody direction. The immunonanoparticles could enhance the sensitivity of MDR cells to ADR cytotoxicity, suggesting its reverse effect on MDR.

Antibiotics, Antineoplastic↗

PubMed2003

[Effect of chondroitin sulfate-A attached titanium surface on culture osteoblast].

OBJECTIVE: To investigation the in vitro effect of CS-A attached titanium surface on the culture of osteoblast. METHODS: We examined the cell proliferation, the ALP activities, and the Calcium contents in the Ostelblast cultured on the Titanium surfaces attached with different concentrations of CS-A Calcium. RESULTS: The CS-A promots the proliferation of osteoblast and increases the calcium content on the titanium disks. CONCLUSION: The biocompatibility of titanium was improved after CS-A attached titanium surface.

Biocompatible Materials↗

PubMed2003

[On preparation the monoclonal antibody against synthetic antigen of cyclosporine A].

OBJECTIVE: To study the methods for preparing the monoclonal antibody against synthetic antigen of cyclosporine A. METHODS: These included using photochemical reaction to couple cyclosporine A with poly-L-lysine as synthetic antigen, immunizing BALB/c mice, fusing spleen cells and SP2/0 cells. Then hybridoma cells were repeatedly screened and subcloned. The monoclonal antibodies were identified by indirect ELISA. RESULTS: Four hybridoma cells in secreting anti-cyclosporine A monoclonal antibodies were obtained. Only two showed high titer and some specificity. CONCLUSIONS: The methods of antigen synthesis and immunization were practicable. But the methods of antibody preparation and preservation need to be improved.

Animals↗

PubMed2003

[The effect of anti-bovine serum albumin B cell clone in mice on preparation of McAb].

OBJECTIVE: To investigate the effect of anti-bovine serum B cell clone in mice on preparation of McAb. METHODS: Supernatant of hybridoma cell was double screened with rSIFN-co and BSA by indirect enzyme-linked immunosorbent assay. After BSA absorption, the inhibition effects on culture supernatant of double positive hybridoma cell clone and rSIFN-co single positive hybridoma cell clones and on normal mouse serum were investigated separately. RESULTS: One double positive cell clone and three rSIFN-co single positive clones were established. The reaction of rSIFN-co with the supernatant of the double positive clone was inhibited obviously on condition that the supernatant was absorbed with BSA in advance. CONCLUSION: In the screening of hybridoma cell, there is rSIFN-co and BSA double positive hybridoma cell clone, which suggests the possible existence of innate anti-BSA B cell clone in mice; they can cause false-positive reaction in the preparation of McAb. Thus, double screening with specific antigen and BSA is beneficial.

Animals↗

PubMed2002

Study on biodegradable microspheres containing recombinant interferon-alpha-2a.

In this work, a new microsphere delivery system comprising calcium alginate microcores surrounded by a biodegradable poly-DL-lactide-poly(ethylene glycol) (PELA) coat was designed to improve the loading efficiency and stability of peptide drugs. Recombinant interferon (IFN)-alpha-2a, used as a model peptide drug, was efficiently entrapped within the alginate microcores using a high-speed stirrer and then microencapsulated into PELA copolymer using a water-in-oil-in-water solvent extraction method. Microspheres were characterized in terms of morphology, size and distribution, encapsulation efficiency, IFN biological activity retention and in-vitro peptide release. The IFN potency test showed that IFN entrapped in the core-coated microspheres could retain its biological activity during the encapsulation and release procedure. The release profiles were determined by the measurement of peptide presenting in the release medium at various intervals. The IFN potency, calculated by the Wish cells/vesicular stomatitis virus system, was used to determine IFN biological activity. The results showed that the core-coated microspheres could stabilize IFN in the PELA matrix. We compared the new deliverysystem with conventional microsphere delivery systems based on biodegradable poly-DL-lactide and poly-DL-lactide-poly(ethylene glycol). The core-coated microspheres had the highest amount of entrapment, encapsulation efficiency and biological activity retention. The extent of burst release (14%) from the core-coated microspheres in the initial protein release was much lower than the 31% burst release from the conventional microspheres. In conclusion, this work presents a new approach for water-soluble macromolecular drugs delivery (e.g. protein, peptide drugs, vaccines).

Biotechnology↗

PubMed2002

[Immune responses of dendritic cells after loaded with cytotoxicity T lymphocyte epitope based peptide of human alpha-fetoprotein (hAFP)].

OBJECTIVE: To study the immune responses of lymphocytes after activated by dendritic cells (DCs) loaded with cytotoxicity T lymphocyte (CTL) epitope based peptide of human alpha-fetoprotein (hAFP, 218-226 LLNQHACAV). METHODS: Get high purity DCs by cultured plastic-adherent monocytes isolated from healthy donor of HLA-A2(+) peripheral blood with granulocyte-monocyte colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days. Stimulate self-lymphocytes with DCs that loaded with CTL epitope based peptide of hAFP under the culture medium contains interleukin-2 (IL-2) for 7 days. Analyse IL-12 and TNF in culture medium and also the specific lysis activity of lymphocytes against four strains of primary hepatocellular carcinoma cells. RESULTS: After stimulated by DC loaded with CTL epitope based peptide derived from hAFP, lymphocytes appeared a good characteristics and the culture medium of activated lymphocytes contained a high level Th1 type cytokines of IL-12 and TNF. Activated lymphocytes not only specifically lysed HLA-A2(+) HepG2 line but also had the cytotoxicity against other three primary hepatocellular carcinoma cell lines and T2 target cell loaded with peptide of hAFP. CONCLUSIONS: The results of this research supply the basic materials for the DC based vaccine with HLA-A2 restricted peptide epitope derived from hAFP against AFP positive primary hepatocellular carcinoma.

Adult↗

PubMed2002

[Cultivation of fibroblasts derived from urethral scar and the effects of salviae miltiorrhizae and ligustrazine on its growth].

OBJECTIVE: To explore the possible effect and related mechanism of salviae miltiorrhizae (SM) and ligustrazine in the treatment of urethral scar. METHODS: In vitro cultivation of fibroblasts derived from urethral scar has been developed. The effects of these two medicines on its morphology and proliferation have been detected based on the in vitro culture system. RESULTS: The spindle cells were found to become elliptical in shape. The two medicines inhibited the proliferation of fibroblasts derived from urethral scar, and this may be resulted from their inhibitive effects on cell division rather than cell necrosis or degradation. CONCLUSION: Salviae multiorrhizae and ligustrazine as effective scar inhibitors may have application prospects in the treatment of urethral stricture.

Adult↗

PubMed2002

[The growth inhibition of colorectal adenoma cells by sulindac and its mechanisms].

OBJECTIVE: This study was conducted to assess the growth inhibition of colorectal adenoma cells by sulindac and identify the possible mechanisms. METHODS: The colorectal adenoma cells from human sporadic adenomatous polyps were cultured, and then treated with sulindac. The cell viability was examined by MTT colorimetric assay; the S-phase fraction and the percentage of apoptosis were measured by flow cytometry. RESULTS: Following sulindac treatment at different concentrations for 24, 48 and 72 hours, reduction of the cell viability was time- and dose-dependent. After 48-hour-treatment, S-phase fraction was decreased and the percentage of apoptosis was increased; both indexes of all groups except 0.3 mmol/L group were different from those of controls (P < 0.05). CONCLUSION: These data suggested that sulindac could inhibit the growth of the colorectal adenoma cells, and its mechanisms might be related to suppressing proliferation and inducing apoptosis.

Adenoma↗