Biomedical subjects

Zhiming Yang

Publications and source records attributed to Zhiming Yang.

At least 19 recordsLinked to original sources

PubMed2006

Decoloration of aqueous Brilliant Green by using glow discharge electrolysis.

This paper described a plasma degradation of Brilliant Green (BG) by glow discharge electrolysis. Various influencing factors such as the voltage, the distance between cathode and anode were examined. Ultraviolet (UV) absorption spectra, gas chromatogram-mass spectrum (GC-MS), and chemical oxygen demand (COD) were used to monitor the degradation process and to identify the major oxidation intermediates. It was confirmed that benzoic acid, 1,2,3,4,5,6-cyclohexanehexaol, and carboxylic acids (e.g., oxalic acid, succinic acid and hydroxyacetic acid) were produced in the degradation process. The results showed that BG rapidly underwent degradation and eventually mineralized into CO(2) and H(2)O.

Carbon Dioxide↗

PubMed2006

Fabrication and detection of tissue-engineered bones with bio-derived scaffolds in a rotating bioreactor.

In order to explore the methods for commercialized bone tissue engineering, engineered bones should be cultivated in bioreactors to realize three-dimensional culture under well-defined culture conditions. In the present paper, osteoblasts isolated from the cranium of 1-month-old Zelanian rabbits were inoculated on to the BDBS (bio-derived bone scaffolds) to investigate the three-dimensional fabrication of engineered bone in an RWVB (rotating-wall vessel bioreactor). The osteoblasts, after being transfected with green fluorescent protein, were respectively seeded at 2 x 10(6) and 1 x 10(6) cells x ml(-1) on to the BDBS and then cultured in a T-flask and an RWVB for 1 week. The morphologies and structure of the fabricated bone were investigated by using an inverted microscope, a scanning electron microscope and a laser confocal microscope using the stains haematoxylin/eosin and Toluidine Blue. After being digested from the scaffolds, the cells were assayed with ALP (alkaline phosphatase) stain, von-Kossa staining on mineralized nodules, type I collagen and bone morphogenetic protein-2 expression, and the cell expansion and growth curves using different culture methods were quantitatively determined with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide). Furthermore, cell cycle and apoptosis were detected by using a flow cytometer, and total DNA was also assayed. For a comparative study, cell-seeded constructs were also cultured under static conditions. The results show that the cell number cultured in the RWVB was five times that in the T-flask. Bone tissues cultured in the RWVB with two different densities grew well, and the osteoblasts maintained their normal cycle and DNA content. The result demonstrates that, with the stress stimulation in the fluid in the RWVB, the active expression of ALP can be increased, rapid proliferation and differentiation of osteoblasts are possible and the three-dimensional fabrication of engineered bone could be realized.

Animals↗

PubMed2006

[The extracellular matrix in bone tissue engineering].

OBJECTIVE: To review the research progress of osteoblast extracellular matrix (ECM) and its application in bone tissue engineering. METHODS: The recent related literatures were extensively reviewed. RESULTS: The ECM was complex in its components. The configuration of cell and cell's adhesion, migration, proliferation, and differentiation were subject to the ECM. The bioactivity of the tissue engineering products was revealed by ECM, which predicted the product's efficiency in clinic application. CONCLUSION: ECM has the potential to become the effective index in evaluating tissue engineered products.

Extracellular Matrix↗

PubMed2006

[Basic study on the development of amniotic membrane and its application].

OBJECTIVE: To review the latest development of amniotic membrane and its application. METHODS: Related literatures on the development of amniotic membrane and its application were extensively reviewed and summarized. RESULTS: There were amniotic epithelial cells and many growth factors in the outer layer of amniotic membrane and there were many kinds of collagen in the basement. The special structure promoted the growth of many kinds of cells. It was widely used in ophthalmology. CONCLUSION: As it is easily available, compatible, cheap in price, low in antigenicity, and able to promote the growth of many kinds of cells, with few ethical problems involved, amniotic membrane will be more and more widely applied.

Amnion↗

PubMed2006

[A comparative study on acellular small intestinal submucosa and acellular amnion as dressings for traumatic skin defects].

OBJECTIVE: To compare the reparative effects between the acellular small intestinal submucosa and the acellular amnion as dressings for traumatic skin defects. METHODS: Three full-thickness skin defects, which were close to the vertebral column of the pig, were created on both sides of the dorsum. The skin defects were randomly divided into three groups. In each group, the following different materials were used to cover the skin defects: the acellular amnion in Group A, the acellular small intestinal submucosa (SIS) in Group B, and the physiological saline gauze in Group C (the control group). The specimens from the skin defects were harvested for a histological evaluation and for determination of the hydroxyproline content at 10 (2 pigs), 20 (2 pigs), and 30 days (3 pigs). We observed the healing process of the wound and its healing rate, counted the inflammatory cells, vascular endothelial cells, and proliferating cells, and determined the hydroxyproline content. RESULTS: The acellular amnion in Group A and the acellular SIS in Group B adhered to the wound tightly, but they did not adhere to the dressing; when the dressing was changed, the wound did not bleed. The saline gauze in Group C adhered to the wound tightly, but when the dressing was changed, the wound bled until 22 days after operation. Under the microscope, the collagen in the tissue below the epithelium was arranged more regularly and there were fewer cells concerned with inflammation in Groups A and B than in Group C at 10, 20, and 30 days after operation. At 10, 20, and 30 days after operation, the wound healing rate was greater in Groups A and B than in Group C. The number of the inflammatory cells and the proliferating cells were greater in Group C than in Groups A and B. There was a statistically significant difference (P < 0.05), At 20 and 30 days after operation, the content of hydroxyproline was greater in Group C than in Group A and B. There was a statistically significant difference (P < 0.05). However, there was no statistically significant difference between Group A and Group B in the wound healing rate, the numbers of the inflammatory cells, vascular endothelial cells and proliferating cells, and the content of hydroxyproline (P > 0.05). There was no statistically significant difference among the three groups in the number of the vascular endothelial cells. CONCLUSION: Compared with Group C, the wound healing rate is improved, the collagen in the tissue below the epithelium is arranged more regularly, and the inflammatory cells, bleeding, and effusion are reduced in Groups A and B. The reparative effects of the acellular amnion and the acellular small intestinal submucosa as dressings on the skin defects are almost the same.

Amnion↗

PubMed2006

[Experimental study on cryopreservation of seeding cells of tissue engineered tendons].

This study sought to find out a good way for the cryopreservation of tendon seeding cells so as to facilitate the preparation of tissue engineering tendons as products. The related questions are how different factors affect cell survival rate at the procedure of preservation and whether cryopreservation affects seeding cells' biological characters as well as collagen secretive function. The results of experiment indicate that DMSO is a more effective cryoprotectant in cryopreservation of tissue engineered tendon seeding cells. Blood serum nourishment is very important in cell culture, preservation and treatment. The same sustenance after cryopreservation increases cell survival rate. In the process of cryopreservation, the concentration of cells is important to cell survival rate; cell survival rate will decrease when it is less than 1.0 x 10(6)/ml. In the process of cryopreservation, the cooling speed is also important to cell survival rate, slow cooling method achieves higher cell survival rate than does the rapid cooling method. Cryopreservation by use of 10%DMSO+15%FCS+75%DMEM does not affect seeding cells' collagen secretive function greatly and does not affect seeding cells' growth curve, cell cycle and chromosome mode obviously. The prescription of 10%DMSO +15%FCS+75%DMEM is suited for the cryopreservation of tendon seeding cells.

Cell Count↗

PubMed2006

[Study on small intestinal submucosa as repair materials in urethral reconstruction].

OBJECTIVE: To explore the possibility of small intestinal submucosa (SIS) for reconstruction of urethral defect. METHODS: Twenty-four male rabbits were divided into 4 groups: group A (the tubular SIS graft for urethral repair), group B (control group, urethral tubular defect), group C (the SIS patch graft for urethral repairs), group D (control group, urethral part defect). Then the regenerative segment was studied with histological technique by hematoxylin-eosin straining and immunohistological straining for alpha-actin after 6 and 12 weeks postoperatively. The retrograde urethrography and urodynamics were used to evaluate the function of the regenerative urethra at 12 weeks after operation. RESULTS: In groups A and C, at 6 weeks after operation, the luminal surface of matrix was completely covered by urothelium, minimal SIS graft was observed in the extracellular matrix, new smooth-muscle cells was confirmed; however, more inflammatory cells were observed in the host-matrix anastomosis in group A than in group C. At 12 weeks postoperatively, the regenerative tissue was equivalent to the normal urethral tissue and SIS disappeared in group C, but some minimal SIS grafts were observed in group A. In groups B and D, urethral strictures and fibrous connective tissue were observed except 3 cases. The urethrography showed wide smooth urethral in group A and C, meanwhile urodynamic evaluation didn't demonstrate significant difference (P > 0.05) in the bladder volume and the maximum urethral pressure between preoperation and postoperation in group A or group C. CONCLUSION: SIS can be a useful material for urethral repair in rabbits, the SIS patch graft is superior to the tubular SIS graft in urethra reconstruction.

Acrylic Resins↗

PubMed2006

[Experimental study on porcine keratinocytes cultured and purified rapidly and cocultured on acellular amnion in vitro].

OBJECTIVE: To explore an effective method to culture and purify porcine keratinocytes, to observe the morphological characteristics of porcine keratinocytes growing on acellular amnion and to offer the experimental basis for that the amnion is used for tissue engineering. METHODS: The primary porcine keratinocytes were cultivated with DKSFM (Defined keratinocyte-SFM) containing 10% fetal bovine serum (FBS). The second passage porcine keratinocytes were cultivated with the medium of DKSFM containing different concentrations of FBS. Because of the speciality that keratinocytes stick to flask fast, we purified the keratinocytes by 0.02% EDTA and 0.05% trypsin step by step. The second passage keratinocytes were seeded on amnion, the keratinocytes/amnion composites were observed by dye directly, histopathology and immunohistochemical staining. RESULTS: The proliferation of the primary porcine keratinocytes cultured with the medium of DKSFM containing 10% FBS was fast and the morphological characteristics were good. The cultivated porcine keratinocytes expanded to 60%-70% of the total area of the bottle of the flask after 5 days. The proliferation of the second passage porcine keratinocytes cultivated with the medium that DKSFM containing 5% FBS was faster than the second porcine keratinocytes cultured with the medium of DKSFM containing 10% FBS, or DKSFM without FBS. The proliferation of the second passage porcine keratinocytes cultivated with DKSFM without FBS was the slowest one among the 3 medium. The porcine keratinocytes that were purified by 0.02% EDTA and 0.05% trypsin step by step were got with high pure. After the keratinocytes were cultivated on the surface of amnion 12 days, the keratinocytes form a single layer on the surface of amnion and the cells were polygon and arranged like slab- stone. After 14 and 16 days, the cells contacted more closely. But at 16 days after the cells were seeded, some of the cells got aging. CONCLUSION: To culture primary porcine keratinocytes with the medium that DKSFM containing 10% FBS and to cultivate the second passage with the medium containing 5% FBS, the proliferation of porcine keratinocytes are faster. The method that purify the porcine keratinocytes is effective. Acellular amnion offers excellent bioscaffold to support keratinocytes to adhere and grow. After the porcine keratinocytes are cultivated on the surface of the acellular amnion 12 days, the morphologic characteristics are better than that of other groups.

Actihaemyl↗

PubMed2006

[The past, present and future of the reparative and reconstructive surgery].

OBJECTIVE: To expound the progress of the reparative and reconstructive surgery (RRS), especially in the recent 20 years, and the developmental direction in the future. METHODS: We reviewed the information from many books, journals, and conference compilations concerned with RRS. RESULTS: RRS emerged with modern surgery. After its development for 20 years, distinguished achievements were obtained in technologies, e.g., biological fixation of bone fracture, bioactive materials, stem cells, tissue engineering, bioactive factor, and induction/derivation regeneration of tissues and organs. Moreover, ideas were continuously refreshed in RRS, such as emphasis on the equal importance of donor and recipient in autologous transplantation, and of structural and functional restoration in dentofacial surgery. CONCLUSION: Further research programs should be conducted, especially in the fields of creative theories, innovative techniques, and rehabilitation engineering.

Humans↗

PubMed2006

[Comparison of two sorts of bio-derived materials after being explanted in the repaired rabbit corneal defect].

OBJECTIVE: To compare the effects of the denuded freeze-dried-amniotic-membrane and the denuded freeze-dried bovine corneal stroma when they were explanted to repair the corneal defect of rabbits. METHODS: The amenia from healthy human placentae were prepared with the method reported by LUO Jingcong, which were freeze-dried and sterilized. The bovine cornea was also denuded by trypsin, rinsed, freeze-dried, and sterilized. Twenty Japan rabbits were divided into group A (the amniotic group) and group B (the bovine-corneal-stroma group) at random. The defect was made, which was 7.5 mm in diameter and 1/3 of the thickness of the cornea, and the two kinds of materials were explanted to repair the defect. The vascularization and the changes of the operated eye were observed. The samples were taken at 2, 4 and 8 weeks for histological examination. RESULTS: The explanted materials were not melted or excluded. There were visible neovessels in both groups, yet there was no significant difference between them. According to the histological observation, there was severe inflammation in both groups 2 weeks after operation, the fibroblasts were proliferated, and the collagen fibers were disorganized; however,the reactions became milder from 4 weeks after operations, and the neovessels could be seen in groups A and B; at 8 weeks, the collagen fibers were more organized in groups A and B; however,there was still a small area of disorganized fibers left. CONCLUSION: The two materials can lead to rejection to some extent, and so they need to be improved.

Amnion↗

PubMed2006

[Expressions of Cbfal and osterix in osteoblasts on human acellular amniotic membrane].

OBJECTIVE: To study the differentiation of the human osteoblasts during the construction of the tissue engineered periosteum with the human acellular amniotic membrane (HAAM). METHODS: To construct the tissue engineered periosteum (n=60) with HAAM, the human fetal osteoblasts were used. The fetal osteoblasts were cultured for 2, 4, 6, 8, and 10 days, and then their total RNA was extracted, which were reversely transcripted to cDNA. The real-time PCR analysis was used to reveal Cbfal and Osterix, and the cycle threshold (Ct) was also measured. The simply-cultured osteoblasts were used as the control group (n=20). RESULTS: The expression of Cbfal was higher in the experimental group on the 2nd day when compared with that on the 4th, 6th, and 8th day (P < 0.05). The same result existed on the 10th day when compared with that on the 4th and 8th day. The expression of Osterix increased and was highest on the 8th day when compared with the other results (P < 0.05). Both of the 2 gene expressions were decreased in the control group when compared with those in the experimental group, but with no significant difference (P > 0.05). CONCLUSION: Cbfal and Osterix can be normally expressed by the osteoblasts after their integration with HAAM. As a scaffold, HAAM can be used to keep the osteoblast phenotype and differentiation with an osteoconductive ability. Such a cell-scaffold complex may provide a basis for the osteogenesis.

Amnion↗

PubMed2005

Identification of steroid derivatives that function as potent antiandrogens.

We have hypothesized that some steroid derivatives bind to the androgen receptor (AR) with very low androgenic activity and therefore potentially function as better AR antagonists than clinically used antiandrogens, such as flutamide. Indeed, we previously found such a compound, 3beta-acetoxyandrosta-1,5-diene-17-one ethylene ketal (ADEK), with some estrogenic activity. Here we report the identification of 2 additional steroid derivatives, 3beta-hydroxyandrosta-5,16-diene (HAD) and androsta-1,4-diene-3,17-dione-17-ethylene ketal (OAK), as new potent antiandrogens. Like ADEK, HAD and OAK could interrupt androgen binding to the AR and suppress both dihydrotestosterone- and androstenediol-induced transactivations of wild-type and mutant ARs in prostate cancer cells. These 2 compounds also inhibited prostate-specific antigen expression in LNCaP as well as growth of different AR-positive prostate cancer cell lines stimulated by androgen. Significantly, HAD and OAK had only marginal agonist effects, as compared to hydroxyflutamide. More importantly, in contrast to ADEK, OAK was shown to possess marginal estrogenic activity. These results strengthen our hypothesis and suggest that selective steroid derivatives could be potent antiandrogenic drugs with less unfavorable effects for the treatment of prostate cancer.

Androgen Antagonists↗

PubMed2005

[Bio-derived bone material].

OBJECTIVE: To review researches on bone defect repaired by different kinds of bio-derived bone. METHODS: The recent relevant literatures were extensively investigated. Preparation of bio-derived bone and effect of bone defect repair were reviewed. RESULTS: The allogeneic and xenogeneic bone treated by different physicochemical method were not only the substitution for bone but also the scaffold material co-cultured with seed cells to reconstruct tissue engineered bone. CONCLUSION: The tissue engineered bio-derived bone is a breakthrough for treatment of bone defect.

Animals↗

PubMed2005

Induction of apolipoprotein E expression by TR4 orphan nuclear receptor via 5' proximal promoter region.

While other plasma lipoproteins are exclusively expressed in liver and intestine, apoliprotein E (apoE) is ubiquitously synthesized in many tissues. To understand the molecular mechanism of non-tissue-specific apoE expression, we tested the testicular orphan receptor 4 (TR4) effect on apoE expression in different cell lines, such as HepG2, COS-1, and H1299 cells. Gel shift assay and 5' promoter activity analyses identified one distinct hormone response element (TR4RE-DR0-apoE at -303 to -292 bp) that binds to TR4 and results in full induction of apoE gene transcription. TR4 also forms a complex with Sp1 to synergistically induce apoE expression via a region containing the TR4RE-DR0-apoE and the Sp1 binding site (-169 to -140 bp). Induction of apoE expression by TR4 was also confirmed at the mRNA and protein levels in H1299 cells. Together, our data demonstrate that TR4 can enhance apoE gene expression via binding to TR4RE-DR0 in apoE 5' promoter and this TR4 binding is essential for synergistic interaction with another transcription factor, Sp1.

5' Flanking Region↗

PubMed2005

[Experimental study on repair of goat tibia defect with marrow stromal cell and bio-derived bone].

OBJECTIVE: To investigate the feasibility of repairing goat tibia defect with marrow stromal cells (MSCs). METHODS: MSCs were cocultured with the bio-derived bone in vitro, and the 20 mm tibia defects were made and fixed with plate in 35 goats, and they were divided into the experimental group, control group and blank group. The defects on the right side were filled with tissue engineering bone as the experimental group, the defects on the left side with bio-derived bone as the control group in 33 goats, and the defect on the both sides were not filled with any materials as the blank group in 2 goats. The repair capability was assessed physically, histopathologically and biomechanically at 2, 4, 6, 8, 12, 16 and 24 weeks after operation in 3 groups. RESULTS: By physical, histopathological and biomechanical examinations, the bio-derived bone was partially absorbed in the experimental group and was rarely absorbed in the control group in the 4th week; the defects were partially repaired in the experimental group, and in the control group, few new bones were observed in the two ends of the implants, in which there was fibrous tissue. The effects of biomechanics had no statistically significant difference between the experimental group and the control group (P>0.05) in the 8th week; the defects were perfectly repaired in the experimental group and the effects of biomechanics had statistically significant difference between two groups (P<0.05) in the 12th weeks. The defects were not repaired in the 24th week in the blank group. CONCLUSION: The tissue engineering bone can efficiently repair bone defect, and its repair capability is better than that of bio-derived bone alone both in quantity and in quality of bone formation.

Animals↗

PubMed2005

[Experimental study on repairing segmental bone defect with bio-derived bone preserved by various methods].

OBJECTIVE: To study the difference of repairing segmental bone defect with bio-derived bone preserved by various methods. METHODS: Freeze-dried biomaterials had been stored in two different preservation solutions for three months, while the biomaterials stored for same period were observed as control group. The experimental model of 15 mm radial segmental defect was made in 60 New Zealand white rabbits, which were divided into groups A, B and C according to transplant materials preserved by various methods. Groups A and B were deeply divided into A1 and A2 subgroups, B1 and B2 subgroups according to whether materials were cocultured with osteoblasts. Tissue engineered bone was used to repair bone defects of left limbs in A1 and B1 subgroups, while simple material to repair defects of right limbs in A2 and B2 subgroups. Group C was divided into C1 and C2 subgroups. Freeze-dried material was used to repair bone defects of the left limbs, while defects of the right limbs as blank control group. The samples were harvested and observed by the roentgenographical, histomorphological, biomechanical and computerized graphical analysis at 4, 8 and 16 weeks. RESULTS: All of the defects treated with implants exhibited new bone formation 4, 8 and 16 weeks postoperatively, increasing with time. The radiological, histomorphological and biomechanical evaluation showed that the ability of new bone formation was arranged in 6 subgroups as follows: A1>A2>C1>B1>B2>C2, the difference was significant between them (P<0.001, P<0.05). The ability of new bone formation was strongest and at 16 weeks the defect was bridged with the appearance of marrow cavities in A1 subgroup, the biomechanical properties in implants approached to those of normal bone. CONCLUSION: The choice of proper preservation solution can improve the ability of repairing bone defect.

Animals↗

PubMed2005

[Expression of interleukin 2 and IL-2 receptor after implanted tissue engineered bones constructed with allogeneic marrow stromal stem cells and bio-derived materials in rhesus monkeys].

OBJECTIVE: To explore the feasibility of allogeneic marrow stromal stem cells (MSCs) as seed cells to construct tissue engineered bone by detecting the expressions of interleukin 2 (IL-2) and IL-2 receptor in rhesus monkeys after implanting these tissue engineered bones. METHODS: Engineered bones were constructed with osteoblasts which derived from allogeneic MSCs and bio-derived materials in vitro, and then were implanted to bridge 2.5 cm segmental bone defects of left radius in 15 rhesus monkeys as experimental group, bio-derived materials only were implanted to bridge same size defects of right radius as control group. Every 3 monkeys were sacrificed in the 1st, the 2nd, the 3rd, the 6th and the 12th weeks postoperatively and the expressions of IL-2 and IL-2 receptor in blood and graft samples were detected quantitatively by enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no significant difference in the contents of IL-2 and its receptor between 2 groups (P>0.05). The contents of IL-2 and its receptor increased from the 2nd week and maintained high level from the 2nd to the 6th week, but decreased after 6 weeks. CONCLUSION: Tissue engineered bones constructed with allogeneic MSCs and bio-derived materials show low immunogenicity. Allogeneic MSCs may be used as seed cells to construct tissue engineered bone.

Animals↗

PubMed2005

[Experimental study on biomechanics characteristics of combined collagen tissue engineering tendon].

OBJECTIVE: To investigate the influence of collagen on the biomechanics strength of tissue engineering tendon. METHODS: All of 75 nude mice were made the defect models of achilles tendons, and were divided into 5 groups randomly. Five different materials including human hair, carbon fibre (CF), polyglycolic acid (PGA), human hair and PGA, and CF and PGA with exogenous collagen were co-cultured with exogenous tendon cells to construct the tissue engineering tendons. These tendons were implanted to repair defect of achilles tendons of right hind limb in nude mice as experimental groups, while the materials without collagen were implanted to repair the contralateral achilles tendons as control groups. In the 2nd, 4th, 6th, 8th and 12th weeks after implantation, the biomechanical characteristics of the tissue engineering tendon was measured, meanwhile, the changes of the biomechanics strength were observed and compared. RESULTS: From the 2nd week to the 4th week after implantation, the experimental groups were stronger than the control groups in biomechanics, there was statistically significant difference (P < 0.05). From the 6th to 12th weeks, there was no statistically significant difference between the experiment and control groups (P > 0.05). Positive correlation existed between time and intensity, there was statistically significant difference (P < 0.05). The strength of materials was good in human hair, followed by CF, and PGA was poor. CONCLUSION: Exogenous collagen can enhance the mechanics strength of tissue engineering tendon, and is of a certain effect on affected limb

Animals↗