Biomedical subjects

Hong Bu

Publications and source records attributed to Hong Bu.

40 records · Page 3Linked to original sources

PubMed2002

[The actuality and trend of biomaterial effectiveness and safety evaluation].

The evaluation of biomaterial effectiveness and safety is a key step before the biomaterial approaches to clinics. In recent years, lots of new biomaterials with different composition, shape, implant site and use have been coming out and in need of more special, sensitive and systematic evaluation methods. With the development of immunology, microdetective technique, inbred strain mammal and other connective branches, there are many chances for the consummation and integration of biomaterial evaluation system. The three-"R" principle (replace, refine, reduce), that is, developing in vitro experiments, using sensitive, special and advanced evaluation methods, improving and reducing the member of experimental animals, as well as the fundamental rule, that is, establishing an evaluation system covering three levels (molecule, cell and body) will guide the research of biomaterial evaluation to more promising development.

Animals↗

PubMed2002

[Human peripheral blood monocyte derived dendritic cell culture and mature regulation].

Mature dendritic cells are potent antigen-presenting cells that initiate primary immune responses, while immature dendritic cells have quite different properties from mature dendritic cells and are tolerance inducer actually. Here we describe the method of using monocyte condition medium to generate dendritic cells of different maturation phases from nonproliferating progenitors in human peripheral blood. The procedure involves two steps. The first step(or priming phase) is to work on a 6-7-day culture of plastic-adherent blood monocyte in medium supplement with GM-CSF and IL-4. The second step (or differentiation phase) requires the exposure to monocyte conditioned medium. Only the dendritic cells generated by the first step are actually immature, with strong immature dendritic cell features such as active endocytosis, the same expression of monocyte marker CD14, and much of the MHC class II still lies within intracellular compartments (MIIC). The second stage dendritic cells have all the features of mature dendritic cell, including a stellate shape, nonadherence to plastic, the expression of dendritic cells restricted marker CD83, and very strong T cell stimulatory function. All of these dendritic cell properties are retained for at least 3 days when the cytokines are removed, suggesting that these populations are stable and terminally differentiated. Since progression from immature to mature dendritic cell is entirely dependent on exogenously added growth factor such as monocyte condition medium, the peripheral blood monocyte may help to harness synchronized population of mature and immature dendritic cells for studies or therapies.

Cell Culture Techniques↗

PubMed2002

[Osteogenesis of HA/TCP biphasic ceramics implanted into muscle: a long-term study].

New bone formation in long-term intramuscle implant of Ca-P biomaterial was investigated in this experiment. After implanting into dog dorsal muscle for 15 months, a thin fibrous membrane that wrapped HA/TCP implant was still observed obviously. Three types of tissues, i.e. mesenchymal tissue, bone and bone marrow, regularly distributed in different pores of implant. Nearly all the pores of implants were occupied by bone. Bone in the pores located in the central region of implant was matured lamellar bone characterized by obvious lacuna and rich bone marrow. However, bone in the peripheral pores was immature woven bone without bone marrow formation. Furthermore, mesenchymal tissues only exist in the peripheral pores and usually were connected with immature woven bone. It was demonstrated that porous HA/TCP has bone inductivity and it could induce new bone formation at non-osseous site. Well-regulated distribution of mesenchymal tissue, bone and bone marrow in the pores suggest bone morphogenesis in the implant must obey a specific space-time program.

Animals↗

PubMed2002

[Antisense inhibition of gene expression in human dendritic cells by peptide nucleic acid against CD86].

OBJECTIVE: Dendritic cells (DCs) are the most potent antigen presenting cells (APCs) of the immune system. We intent to block the expression of CD86 in DCs using antisense peptide nucleic acids (PNA), a novel synthetic structural DNA mimic, and interrupt the second signal transmission so that a suppression of corresponding T cell function can be achieved. METHODS: Human DCs grown up from peripheral blood monocytes in GM-CSF and IL-4 were collected. We investigated antisense PNA internalization with laser scan confocal microscope (LSCM). Fluorescence immunocytochemistry, flow cytometry and RT-PCR were used to determine the expression of CD86 protein and mRNA in DCs. RESULTS: LSCM proved that cultured immature DCs could internalized PNA efficiently, according to the specific internalization property of the immature DCs. Antisense PNA DC exhibited striking reductions in cell surface staining for CD86, but not MHC class II, and were poor stimulators of T cell proliferation. RT-PCR found that PNA depressed the amounts of CD86 mRNA in DCs. CONCLUSION: Antisense PNA against CD86 could inhibit the expression of CD86 mRNA and protein in DCs. The blockade of B7/CD28 pathway may increase the potential of costimulatory molecule-deficient antisense PNA DCs of donor origin to induce long-lasting allograft survival.

Antigens, CD↗