Biomedical subjects

Zhiming Yang

Publications and source records attributed to Zhiming Yang.

At least 55 records · Page 3Linked to original sources

PubMed2005

[The effect of platelet gel in reparative and reconstructive surgery].

OBJECTIVE: To review the information of platelet gel used in the basic and clinical research in reparative and reconstructive surgery. METHODS; Literature about platelet gel used on the basic and clinical research was obtained through searching medical data and Internet. The effect of platelet gel on repairing and reconstructing the function and structure of tissue and organ was analyzed. RESULTS: Platelet gel had many growth factors and had the ability to improve wound healing and regeneration of bone and other tissues. CONCLUSION: Platelet gel is widely available and almost genuine and is able to improve regeneration of many kinds of tissues. Extensive and intensive research should be made on its clinical application.

Animals↗

PubMed2005

[Advance in researches on materials for abdominal wall defect].

How to succeed in repairing an immense abdominal wall defect is often a perplexed question for surgeons. Finding perfect substitute material, therefore, is of great importance. The materials in this regard are often divided into two categories: biomaterial and non-boimaterial. The former has excellent mechanics properties while the latter possesses more favourable biocompatibility. The characteristics, clinical effects and advantages of biomaterials and non-biomaterials for abdominal wall repair are reviewed.

Abdominal Wall↗

PubMed2004

Androgen receptor (AR) NH2- and COOH-terminal interactions result in the differential influences on the AR-mediated transactivation and cell growth.

Early reports showed that androgen receptor (AR) NH2- and COOH-terminal (N-C) interaction was important for full AR function. However, the influence of these interactions on the AR in vivo effects remains unclear. Here we tested some AR-associated peptides and coregulators to determine their influences on AR N-C interaction, AR transactivation, and AR coregulator function. The results showed that AR coactivators such as ARA70N, gelsolin, ARA54, and SRC-1 can enhance AR transactivation but showed differential influences on the N-C interaction. In contrast, AR corepressors ARA67 and Rad9 can suppress AR transactivation, with ARA67 enhancing and Rad9 suppressing AR N-C interaction. Furthermore, liganded AR C terminus-associated peptides can block AR N-C interaction, but only selective peptides can block AR transactivation and coregulator function. We found all the tested peptides can suppress prostate cancer LNCaP cell growth at different levels in the presence of 5alpha-dihydrotestosterone, but only the tested FXXLF-containing peptides, not FXXMF-containing peptides, can suppress prostate cancer CWR22R cell growth. Together, these results suggest that the effects of AR N-C interactions may not always correlate with similar effects on AR-mediated transactivation and/or AR-mediated cell growth. Therefore, drugs designed by targeting AR N-C interaction as a therapeutic intervention for prostate cancer treatment may face unpredictable in vivo effects.

Amino Acid Motifs↗

PubMed2004

Androgen receptor regulates expression of skeletal muscle-specific proteins and muscle cell types.

C2C12 myoblasts expressing the androgen receptor (AR) were used to analyze the role of androgen-AR signaling pathway in skeletal muscle development. Marked up-regulation of AR expression was observed in differentiated myotubes. A nuclear run-on transcription assay demonstrated that transcription of the AR gene is increased during skeletal muscle cell differentiation. Regulation of skeletal muscle-specific protein expression by the androgen-AR signaling pathway was further analyzed using quadriceps skeletal muscle from wild-type (WT) and AR knock-out (ARKO) male mice. A histological analysis of quadriceps skeletal muscle indicates no morphological differences between ARKO and WT mice. However, the androgen-AR signaling pathway increases expression of slow-twitch-specific skeletal muscle proteins and downregulates fast-twitch-specific skeletal muscle proteins, resulting in an increase of slow-twitch muscle fiber type cells in quadriceps muscle.

Animals↗

PubMed2004

[Basic researches on cell adhesion and its application in tendon tissue engineering].

Cell adhesion is a basic and very important tissue in the field of tissue engineering. Fibronectin and integrins are the most important elements to cell adhesion. Some surface receptors of fibroblast can also conjugate with type I collagen in extracellular matrix (ECM) directly. Laminin receptors on the surface of fibroblast bound to laminin also play a role in cell adhesion. In this paper are reviewed a number of related articles. The structures and function of fibronectin and integrins are discussed in detail; the tendon cell's adhesion structures are also discussed. Yet, there was scarcely any paper on the effects which the preservation of tissue engineered products may have on cells' adhesion fo ECM. Therefore, researching on cell adhesion and finding a way of preservation that has no or very little adverse effect on cell adhesion is an important topic. Results from expected advanced researches on cell adhesion may probably find promising applications in the field of tissue engineering.

Cell Adhesion↗

PubMed2004

[Limb salvage surgery for wrist in bone tumor by using free vascularised fibular graft with fibular head or simple fibular graft].

OBJECTIVE: To compare the long-term results of vascularised fibular graft and simple autologous fibular graft for reconstruction of wrist after distal bone tumor resection. METHODS: From January 1979 to September 2002, 15 patients with wrist defects due to distal bone tumor resection were treated with vascularised fibular graft or simple autologous fibular graft and followed up 1 year. The results were graded with Enneking's system and evaluated radiographically according to the "International Symposium on Limb Salvage". The grade system included limb function, radiological examination and the function of ankle. RESULTS: The limb function of 8 patients with vascularised fibular graft restored to 80% of normal function and the bone union was achieved within 6 months. The limb function of 6 patients with simple autologous fibular graft restored to 67% of normal function. The bony union was achieved within 6 months in 4 cases with the bone graft less than 5 cm and in the 13th and 16th months in 2 cases with the bone graft more than 12 cm. CONCLUSION: It is suitable to use the head of fibular bone as a substitute for the distal radius. The healing of vascularised fibular graft is very quick and haven't the bone resorption. So in the procedure for reconstruction and limb salvage after bone tumor resection of distal radius, the free vascularised fibular graft with fibular head is an ideal substitute.

Adolescent↗

PubMed2004

[Effect of various storage methods on cellular compatibility of bio-derived bone].

OBJECTIVE: To study the effect of various storage methods on cellular compatibility of bio-derived bone. METHODS: Freeze-dried biomaterials had been stored in two different preservation solutions for three months, while the biomaterials stored for the same time were observed as control group. The experiment was divided into groups A, B, C and D according to different storage methods (group A: with materials stored in preservation solution 1; group B: with materials stored in preservation solution 2; group C: with freeze-dried materials; and group D: simple osteoblasts). Osteoblasts at 2 x 10(6)/ml had been cocultured with materials for 1, 3, 5, and 7 days. The cell-material complex was observed under phase microscope and electronic scanning microscope to evaluate the adhesion and growth of osteoblasts; the cell viability and alkaline phosphatase(ALP) activity were measured, and the cell cycle was analysed by flow cytometer. RESULTS: Osteoblasts adhered to materials preserved by different methods, differentiated and proliferated in the hole of materials. The difference of cell viability was not significant between three groups on day 1 and day 3. The cell viability of osteoblasts adhered to three materials was A > C > B group on day 5 and day 7 (P < 0.01, P < 0.05). The ALP activity of osteoblasts adhered to three materials was A > C > B group on day 7 (P < 0.01). The cell cycle of different groups did not change significantly, the abnormal cells were not seen. CONCLUSION: The choice of proper preservation solution can optimize the cellular compatibility of bio-derived bone.

Alkaline Phosphatase↗

PubMed2004

[Effect of different allogenic cells injected into denervated muscles on nerve regeneration in rats].

OBJECTIVE: To study the effect of allogenic different cells injected into denervated muscles on nerve regeneration. METHODS: Thirty-six adult female SD rats, weighted 120-150 g, were divided into four groups randomly (n = 9, each group). Left sciatic nerves were cut down on germfree conditions and given primary suture of epineurium. Different cells were injected into the muscles of calf at once after operation every seven days and in all four times (group A: 1 ml Schwann cells at concentration of 1 x 10(6)/ml; group B: 1 ml mixed cells of Schwann cells and myoblast cells at concentration of 1 x 10(6)/ml; group C: 1 ml extract from the culture medium of kidney endothelial cells; and group D: 1 ml culture medium without FCS as control). After 3 months, the specimen was observed on macrobody and histology, and the densities of neurilemma cell and myoceptor were counted. RESULTS: The means of proximate neurilemma cells were 0.1877 +/- 0.0542 in group A, 0.1551 +/- 0.0321 in group B, 0.0724 +/- 0.0237 in group C, and 0.1877 +/- 0.0542 in group D. The densities of myoceptor were 6.000 +/- 0.866 in group A, 9.000 +/- 2.291 in group B, 12.780 +/- 1.394 in group C, 3.110 +/- 0.782 in group D. CONCLUSION: Schwann cells, mixed cells of Schwann cells with myoblast cells, and the extract from kidney endothelial cells can all accelerate the nerve regeneration. And the effect of extract from the kidney endothelial cell is superior to that of Schwann cell and mixed cell.

Animals↗

PubMed2004

[Effect of exogenous collagen on cell function in construction of artificial biotendon in vitro].

OBJECTIVE: To investigate the influence of the exogenous collagen on the function of cells in construction of artificial biotendon. METHODS: Three materials including human hair, carbon fiber (CF) and polyglycolic acid (PGA) were combined with exogenous collagen and co-cultured with standard transferred human embryonic tenocytes at a concentration of 3 x 10(6)/mm3 in vitro. The cell number and morphology were observed under inverted microscope and scanning electron microscope after 2 hours, 3 days and 5 days. RESULTS: In the artificial biotendon combined with collagen, the cells concentrated around the materials and the cells adhering to the materials turned into round after 2 hours. After 3 days, the adhering cells increased. After 5 days, the shape of the cells changed from round to spindle. CONCLUSION: Exogenous collagen will facilitate the cells to adhere onto materials and proliferate.

Animals↗

PubMed2004

[Histologic pattern and mechanical properties of tissue-engineered tendon implants for tendon defects].

This is a study on the histologic pattern and mechanical properties of tissue-engineered tendon implanted for treatment of tendon defects. Tendons were resected from Roman chickens. Tendon cells were isolated from the tendons and cultured in vitro. The 2nd-4th passages of tendon cells were seeded on the degradable polyglycolic acid mesh to form cell-scaffold composites, which were further cultured for 7-10 days to construct tissue-engineered tendons. The tendon defects, 0.5 cm-0.8 cm in length, were made in the second digit flexor tendon bilaterally in 20 Roman chickens and then bridged with the constructed tissue-engineered tendons. At 2 weeks, 4 weeks, 6 weeks, and 8 weeks post-operation, the samples of regenerated tendons were collected for gross examination, histologic staining and biomechanical test. After implantation of the tissue-engineered tendons, the wounds healed well. The gross appearance, the cells and collagen fibers arrangement of the regenerated tendons were similar to those of natural tendons, but there were relatively not many closely packed collagen fiber bundles organized in parallel with the tendons ("remodel"), so the maximum tensile force increased slowly and its value was 15.40+/-10.63 N at 8 weeks after surgery, reaching only 23% of that of natural tendon. The maximum strain was 22.49%+/-10.21% at 8 weeks, being 10% higher than that of natural tendons. Polyglycolic acid scaffolds are degraded in vivo so rapidly that the regenerated tendons lose the normal biomechanical stimulus and then are unable to be remodeled. As a result, the mechanical strength of regenerated tendons is much lower than that of natural tendons. These results suggest that the normal biomechanical stimulus may be an important factor for the regenerated tendons to remodel.

Animals↗

PubMed2004

[Possibility of using cartilage cultured in centrifuge tube as a substitute for meniscus].

OBJECTIVE: To compare biological characteristics between articular chondrocyte and meniscal fibrochondrocyte cultured in vitro and to investigate the possibility of using cultured cartilage as a substitute for meniscus. METHODS: Chondrocytes isolated from articular cartilage and meniscus of rabbits aged 3 weeks were respectively passaged in monolayer and cultured in centrifuge tube. Cartilages cultured in centrifuge tube and meniscus of rabbit aged 6 weeks were detected by histological examination and transmission electron microscopy. Growth curves of articular chondrocytes and meniscal fibrochondrocytes were compared; meanwhile, cell cycles of articular chondrocytes and meniscal fibrochondrocytes in passage 2 and 4 were separately measured by flow cytometry. RESULTS: Articular chondrocytes in passage 4 were dedifferentiated. Articular chondrocytes formed cartilage 2 weeks after cultivation in centrifuge tube, but meniscal fibrochondrocytes could not generate cartilage. The differences in ultrastructure and histology obviously existed between cultured cartilage and meniscus; moreover, apoptosis of chondrocytes appeared in cultured cartilage. Proportion of subdiploid cells in articular chondrocytes passage 2 and 4 was markedly higher than that in passage 2 and 4 fibrochondrocytes (P < 0.05). CONCLUSION: Meniscal fibrochondrocytes can not form cartilage after cultivation in centrifuge tube, while cartilage cultured in centrifuge tube from articular chondrocytes can not be used as graft material for meniscus. Articular cartilage is markedly different from meniscus.

Animals↗

PubMed2004

[Effect of human acellular amnion membrane on tendon adhesion in rat].

OBJECTIVE: To investigate the effects of human acellular amnion membrane on SD rat tendon adhesion and to obtain the experimental data for clinical application in preventing postoperative tendon adhesion. METHODS: The tendons of 28 adult SD rats hindlimb were cut and sutured. The tendons of left hindlimb were encapsulated by human accellular amnion membrane as the experimental group and the ones of the other side were not encapsulated as control group. The rats were killed 1, 2, 4, 6, 8 and 12 weeks after operation. The results were evaluated grossly and histologically. RESULTS: There were no differences in healing of injury tendon and inflammatory response between the two groups. The anatomical and histological results showed the experimental group had less adhesion than the control group (P < 0.05). CONCLUSION: Human acellular amnion membrane can prevent adhesion of tendon without affecting tendon healing and is an optimal biological material to prevent tendon adhesion.

Amnion↗

PubMed2004

[Cellular compatibility of small intestinal submucosa in vitro].

This study was aimed to evaluate the cellular compatibility of the small intestinal submucosal(e) (SIS). Prepared by use of pig jejunum. SIS were cocultured with human embryonic periosteal osteoblasts (HEPOB), human embryonic skin fibroblasts (HESFB) and rabbit renal vascular endothelial cells (RRVEC) respectively. The cell growth, attachment, cell cycle, cell apoptosis rate were detected to evaluate the cellular compatibility of SIS. The three kinds of cells attached onto SIS and grew well. SIS accelerated the growth of RRVEC. No effects of SIS were detected on cell cycle and cell apoptosis rate in the three kinds of cells. SIS has good cellular compatibility without cytotoxicity. The porous structure of SIS is suited for the growth of HEPOB, HESFB and RRVEC in three dimensions in the scaffold. SIS is a good bio-derived material of tissue engineering.

Animals↗

PubMed2004

[The cryopreservation technology in research and development of tissue engineered products].

In this brief review, some key issues related to cryopreservation of seeding cells, scaffolds, and engineered tissues are outlined. The importance of cryopreservation technology to the research and development of tissue engineered products is demonstrated. The biological or biochemical reaction rate must be reduced or completely shut off in order to preserve the tissue engineered products for a long period of time. Cryopreservation may be one of the possible approaches to the fulfillment of this requirement. Seeding cells are stored at low temperature. Tissue engineered scaffold products are usually lyophilized. Engineered tissues are preserved by vitreous cryopreservation technology.

Cell Count↗

PubMed2004

[Recent researches on the responses of fibroblasts exposed to cyclic mechanical stretching in vitro].

Recently, in vitro dynamical cell-culture has been drawing more and more attention from researchers in the areas of tissue engineer, and a series of researches have demonstrated that cyclic mechanical stretching has significant effects on the cell proliferation, differentiation, and on the cell alignment on scaffold, as well as on the synthesis of extracellular matrix, cytokines, and matrix metalloproteinases (MMPs). By focusing on reviewing the culture of several kinds of fibroblasts in vitro, we learned that these cellular responses mentioned above induced by cyclic mechanical stretching were tested by many precisely designed experiments, and assumed that cyclic mechanical stretching, if applied properly, would contribute significantly to our purpose of constructing more sophisticated tissue-engineered tendon and ligament.

Cell Differentiation↗

PubMed2003

Effects of baicalin-modified poly(D,L-lactic acid) surface on the behavior of osteoblasts.

In the present study, the functions of rat calvaria osteoblasts on baicalin-modified poly(D,L-lactic acid) (PDLLA) films were investigated in vitro. The surface characteristics of surfaces (both modified and control) were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). Cell morphologies on these surfaces were examined by scanning electron microscopy (SEM). Cell adhesion and proliferation were used to assess cell growth on the modified and control surfaces. The MTT assay was used to determine cell viability and alkaline phosphatase (ALP) activity was performed to evaluate differentiated cell function. Compared to control films, cell attachment of osteoblasts on baicalin-modified PDLLA film was significantly higher (P<0.05 and P<0.01) after 6 h and 8 h culture, and cell proliferation was also significantly greater (P<0.05 and P<0.01) at the end of 4th and 7th day, respectively. The MTT assay suggested that the cell viability of osteoblasts cultured on baicalin-modified PDLLA film was significantly higher (P<0.05) than that seeded on the control. Meanwhile, the ALP activity of osteoblasts cultured on modified films was also considerably enhanced (P<0.01) compared to that found on control. These results revealed that the biocompatibility PDLLA could be improved by surface modification with baicalin.

Journal Article↗

PubMed2003

[The related research of tissue-engineered tendon in vivo].

Using tissue-engineered tendons to repair tendons and ligaments as well as functional reconstruction is the focus of nowadays researches. The scaffolds must be not only unharmful to health, but also easy for cells attachment, and be able to induce collagen deposition to form a neotendon with mechanic properties similar to those of normal tendon. In recent researches, it has been found that the mechanic properties of the implants change with the degrading and femdonizing of scaffolds. The relationships between collagen deposition, scaffolds degradation and mechanic properties of neotendon need to be defined more clearly.

Animals↗

PubMed2003

[Biomechanical properties of tissue-engineered tendons after repairing digital flexor tendons in chickens].

Experiments have been performed to investigate why the biomechanical strength of repaired tendons is lower than that of the normal tendon when the engineered tendons are implanted in vivo to replace the tendon defects. We seeded the primary culture tendon cells derived from Roman chickens' digital flexor tendons on the degradable polyglycolic acid meshes to construct tissue-engineered tendons. The flexor tendon defects (0.5 cm-0.8 cm) excised in second digit bilaterally in 20 Roman chickens, had been repaired with the constructed tissue-engineered tendons. The samples of repaired tendons were collected at 2, 4, 6 and 8 weeks after operation. Tests for scaffold weight, hydroxyproline content, and mechanical strength of the samples were performed. We found that from 2 weeks to 8 weeks afteroperation, the weight of the scaffolds decreased significantly, almost disappearing at 8 weeks; the hydroxyproline content determining the total collagen content increased gradually without significance; mechanically, both energy at break and tensile strength showed a tendency of drastic decrease at first 4 weeks afteroperation and a gradual increase afterwards, but the tensile strength at 8 weeks afteroperation was only 23% of that of the normal tendon. We conclude that the lower biomechanical strength of repaired tendons is owing to the serious mismatch between scaffold degradation and collagen synthesis.

Achilles Tendon↗