Post-marketing multi-center safety surveillance of inactivated enterovirus A71 vaccine (Vero cell) / 中华预防医学杂志

Objective@#To evaluate the post-marketing safety profiles of the inactivated enterovirus type 71 (EV-A71) vaccine (Vero cell) after routine inoculation.@*Methods@#Eleven cities of Zhejiang Province, Fengtai district of Beijing, Qinnan district, two counties as Pingle and Pingguo of Guangxi Zhuang Autonomous Region, and Dongtai city of Jiangsu Province were selected as the field sites. A total of 45 239 subjects were enrolled in this study from children who seeked the vaccination of EV-A71 vaccine during the period from July, 2016 to June, 2018. Different sampling method were adopted in different sites. All vaccinated children were invited to participate in the study in Fengtai and Dongtai, however, systematic sampling method were adopted in other sites. Active surveillance was conducted and information about adverse reactions (ARs) occurred in 30 min, 3 d and 30 d following each dose of EV-A71 immunization was collected by field observation, phone-call or face-to-face interview. The incidence of ARs in different types, symptoms and grades were described.@*Results@#In total, there were 45 239 children who received 71 243 doses EV-A71 vaccine. The overall incidence of ARs was 1.079% (769 doses), with the highest incidence of 1.182% (177/14 973) in 5-11 month group and the lowest incidence of 0.849% (18/2 119) in ≥ 36 month group among different age groups. There was a higher incidence in solicited ARs, which was 1.047% (746 doses). The incidences of grade 1 and grade 2 ARs were also higher, which were 0.404% (288 doses) and 0.554% (395 doses), respectively. No grade 4 ARs occurred. The doses of the first and the second vaccination was 40 736 and 30 507, respectively, and the incidences of ARs were 1.281% (522 doses) and 0.810% (247 doses). Also, the incidences of ARs were 0.091% (37 doses) and 0.043% (13 doses) in local, and 1.168% (476 doses) and 0.760% (232 doses) in system. The symptoms of ARs after the two doses of vaccination were basically the same. Redness at the injection site was the most common local ARs after each dose vaccination, with doses of 24 and 11, while fever was the most common systemic ARs, with doses of 362 and 190. Moreover, ARs mainly occurred in 30 min to 3 d after each dose vaccination, with incidence of 1.016% (414 doses) and 0.698% (213 doses) in the first and second dose, respectively.@*Conclusion@#The ARs had a low incidence after vaccination in children and most were mild or moderate. EV-A71 vaccine with good safety is suitable for inoculation in a large scale.

Adenovirus-mediated RNA interference against core binding factor alpha 1 inhibits the hypertrophic differentiation of chondrocytes / 中国组织工程研究

BACKGROUND:Hypertrophic differentiation of chondrocytes is the sign of starting endochondral ossification, and it is also an essential step in endochondral ossification, which is a cascade reaction and difficult to be blocked once started. The end result is the formation of bone structure. RNA interference is a post-transcriptional gene silencing. Relevant studies have shown that the use of RNA interference to block the expression of core binding factorα1 (Cbfα1) can effectively inhibit the formation of heterotopic ossification. OBJECTIVE:To use RNA intereference technology to suppress Cbfα1 expression so as to achieve the purpose of blocking the hypertrophic diferentiation of chondrocytes. METHODs: We constructed an adenovirus containing siRNA against Cbfα1 (Ad-Cbfα1-siRNA). Retinoic acid and interleukin-1α were used to induce hypertrophic differetiation of chondrocytes, and then Ad-Cbfα1-siRNA was utilized to inhibit the hypertrophic differentiation of chondrocytes. Immunohistochemistry method was used to analyze the expression of Cbfα1. RESULTS AND CONCLUSION:After induction with retinoic acid and interleukin-1α, the chondrocytes in the negative control virus group appeared to have hypertrophy and the expression of Cbfα1 was positive. In the Ad-Cbα1-siRNA group, the expression of Cbfα1 was negative. These findings suggest that the inhibition of Cbfα1 by RNA interference can be a powerful way to prevent the hypertrophic differentiation of chondrocytes .

Small intestine submucosa as a scaffold for cartilage reconstruction in vitro / 生物医学工程学杂志

This paper is aimed to investigate the feasibility of applying the small intestine submucosa (SIS) as the scaffold in constructing tissue engineering cartilage in vitro. We obtained SIS from the small intestine of specific pathogen-free pigs. Then we isolated tunica submucosa layer from the mucosal, muscular, and serosal layers by gentle mechanic abrasion. The SIS was made acellular by combination of detergent and enzyme digestion. The chondrocytes were seeded onto the SIS and were cultured for 3 weeks. The cell growth, attachment and distribution were detected by histochemical stain, immunohistochemical stain and scan electron microscope. The chondrocytes could adhere and grow well on the matrix surface, and synthesize a large of the GAG and type U collagen. However, the chondrocytes grew only on the surface andsuperficial layer of the scaffold, they did not move into the inner part of the scaffold. It could be concluded that SIS has good cellular compatibility without cytotoxicity and provides temporary substrate to which these anchorage-dependent cells can adhere, and stimulate the chondrocytes anchored on the scaffold to proliferate and keep differentiated phenotype. Further study will be needed to promote the ability of chondrocyte chemotaxis in order to distribute the chondrocytes into the whole scaffold uniformly.

Change of rabbit peripheral blood T lymphocyte subsets in the early period following transplantation of tissue engineered bone constituted by partially-deca Icified freeze-dried bone / 中国组织工程研究

BACKGROUND:Freeze-dried bone has strong immunogenicity due to insufficient removal of xenoantigen.Deproteinized bone and completely-decalcified bone have weak antigenicity,but the fomer has no osteoinductive property,and the latter has poor biomechanical property,so both of tem are limited in clinical application.OBJECTIVE:To observe the change of rabbit peripheral blood T lymphocyte subsets after transplantation of tissue engineered bone constituted by partially-decalcified freeze-dried bone scaffold and the histological changes of transplanted tissue.DESIGN,TIME AND SETTlNG:Randomized grouping,controlled animal observation.Performed in the State Key Laboratory of Biotherapy(I.E.Department of Stem cells and Tissue Engineering),Huaxi Hospital,Sichuan University between June 2006 and June 2007.MATERlALS:Tissue-engineered bone was in vitro constructed using osteoblasts.Which were derived from rabbit periosteum and used as seeding cells,and xenogeneic cancellous bone,which were antigen self-digested,partially-decalcified freeze-dried bone.METHODS:Forty-eight rabbits were randomly divided into the following 4 groups,with 12 rabbits in each group:partially-decalcified freeze-dried bone group(partially-decalcified bone group),tissue engineered bone group,autogenous bone group.And allogeneic bone group.Partially-decalcified freeze-dried bone,tissue engineered bone,autogenous bone,and allogeneic bone were respectively implanted into the 1 cm segmental defect in rabbit radius in above-mentioned groups.MAINOUTCOME MEASURES:Prior to and 1,2,and 4 weeks after implantation,the change of rabbit peripheraI blood T lymphocyte subsets were examined by flow cytometry；At 2,4,8,and 12 weeks after implantation,osteogenesis of the 4 materials was examined by routine histological examination.RESULTS:①In the partially-decalcifled bone group,peripheral blood CD4+and CD8+1r lymphocytes were significantly increased at 1 and 2weeks afterimplantationthan priortoimplantation(P<0.05).At 4 weeks after implantation.CD4+T lymphocytes were increased,but not significantly,compared with prior to implantation(P>0.05).In the autogenous bone group,CD4’and CD8+T lymphocytes were increased,but not significantly(P>0.05).In the allogeneic bone group,CD4’and CD8+T lymphocytes were significantly increased at weeks 1,2,and 4 after implantation than prior to implantation and the synchroale phase in the other groups(P<0.05).②inthetissue engineeredbonegroup,at week 2 after implantation,osteoblasts and chondroblasts were visible in the material porous,in addition,a new mixed tissue containing bone and cartilage formed and surrounded by osteoclasts,and partial rack was destroved and absorbed.At week 4,newly formed bone had turned into woven bone.At week 8.Lamellar bone was foand.And partially-decalcified freeze-dried bone was completely degraded and absorbed.At week 12,the implant had been completely substituted by lamellar bone,and medullary cavity was recanalized.CONCLUSION:Tissue-engineered bone constituted by taking partially-decalcified freeze-dried bone as scaflfold led to an increase in peripheral blood T lymphocytes,but which did not influence its good repair capabmtv of bone defects.

Histologic pattern and mechanical properties of tissue-engineered tendon implants for tendon defects / 生物医学工程学杂志

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.

Cellular compatibility of small intestinal submucosa in vitro / 生物医学工程学杂志

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.

Observation of the morphological change during the adipogenesis differentiation of human bone marrow stromal cell / 中国康复理论与实践

@#ObjectiveTo study the variant differentiated phase of the human bone marrow stromal cell (MSC) during induced adipogenesis course by morphological observation.MethodsAfter proliferated in vitro, MSCs isolated from bone marrow of the female adults volunteers were cultured with the adipogenetic inducers for 6—30 days. Morphological changes of the cells were observed everyday under Olympus contrast phase microscopy, and some specimens were stained with Oil-red-O.ResultsMSC showed long spindle shape before inducing, and then changed gradually to oval or round shape and the figure enlarged simultaneously. There were specifically morphological changes with lipid droplet emergence under plasmalemma and confluence gradually to lipid drop during differentiated into the phase of immature and mature adipocyte.ConclusionIt is easy to detect the MSC differentiated into the phase of immature and mature adipocyte with the specific morphological change of lipid droplet, while in the phase of preadipocyte and adipoblast, there is no special morphological change, and it may need some specific markers to detect.

Biomechanical properties of tissue-engineered tendons after repairing digital flexor tendons in chickens / 生物医学工程学杂志

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.

Experimental studies on gradient degradation biomaterials combined with cultured tenocytes in vitro / 中华显微外科杂志

0.05),hints that the tenocyte's function was not disturbed. The DNA index of cells of GDBM group was 0.96 and 2.1% higher than the control group,indicating that the tenocytes grow and proliferate faster when being combine cultured on GDBM. Conclusion GDBM show good biocompatibility combined with tenocytes and they are promising extracellular matrix scaffold for cell transplantation in tendon tissue engineering.