Novel Fluorinated Anion Exchange Membranes Based on Poly(Pentafluorophenyl-Carbazole) with High Ionic Conductivity and Alkaline Stability for Fuel Cell Applications.

Constructing good microphase separation structures by designing different polymer backbones and ion-conducting groups is an effective strategy for improving the ionic conductivity and chemical stability of anion exchange membranes (AEMs). In this study, a series of AEMs based on the poly(pentafluorophenylcarbazole) backbone grafted with different cationic groups are designed and prepared to construct well-defined microphase separation morphology and improve the trade-off between the properties of AEMs. Highly hydrophobic fluorinated backbone and alkyl spaces enhance phase separation and construct interconnected hydrophilic channels for anion transport. The ionic conductivity of the PC-PF-QA membrane is 123 mS cm-1 at 80 °C, and the ionic conductivity of the PC-PF-QA membrane decreased by only 6% after 960 h of immersion at 60 °C in 1 M NaOH aqueous solution. The maximum peak power density of the single cell based on PC-PF-QA is 214 mW cm-2 at 60 °C.

Sustained expression of HPV16 E7 oncoprotein promotes p-AKT(Ser473)/p-Src(Tyr527) signaling to drive precancerous lesions to invasive cervical cancer.

Human papillomavirus (HPV) E7 oncogene plays the most important role in cervical cancer. However, whether E7 oncoprotein is continuously expressed, associated with AKT(Ser473)/p-Src(Tyr527) signaling to trigger cervical carcinogenesis remains unclear. Here, we explored first if HPV16 E7 oncoprotein could be detected in clinical biopsies and is sustainedly expressed, and then investigated how this oncoprotein interacted with AKT(Ser473)/p-Src(Tyr527) signaling in cancer progression. We used ZHPV16E7384 affibody to detect E7 expression in HPV16-positive cervical cancer biopsies and animal tumors by immunohistochemistry (IHC). Results showed that ZHPV16E7384 affibody had intense and specific staining for E7 oncoprotein in the detected specimen. The E7 oncoprotein was continuously expressed to correspond with the development of precancerous lesions to invasive cervical cancer. IHC staining also revealed that AKT, p-AKT(Ser473), Src and p-Src(Tyr527) proteins were expressed in both patient biopsies and animal tumors, with the highest levels of p-AKT(Ser473)/p-Src(Tyr527) present in invasive cancer. Furthermore, siRNA experiments revealed that HPV16 E7 knockdown significantly impaired expression of p-AKT(Ser473)/p-Src(Tyr527) in both HPV16 E7-positive cancer cells and transformed cells. In addition, transient expression of HPV16 E7 protein promoted significantly expression of p-AKT(Ser473)/p-Src(Tyr527) in primary human keratinocytes. Finally, co-immunoprecipitation analysis proved that HPV 16 E7 protein interacted reciprocally with p-AKT(Ser473)/p-Src(Tyr527). In conclusion, we demonstrate that HPV16 E7 oncoprotein is continuously expressed to promote expression of p-AKT(Ser473)/p-Src(Tyr527) leading to drive the initiation and progression of cervical cancer. Our data provide a novel insight that HPV16 E7 activates p-AKT(Ser473)/p-Src(Tyr527) to establish a mechanistic link between the oncogene and the AKT/Src signaling to trigger cervical carcinogenesis.

A model for long-term infection of bovine papillomavirus type 1 in Saccharomyces cerevisiae.

We have previously reported that bovine papillomavirus type 1 (BPV1) can replicate its genome and produces infectious virus-like particles in short-term BPV1 virion-infected Sacharomyces cerevisiae (Zhao and Frazer, 2002). Here, we report viral RNA transcription and L1 capsid protein expression in long-term BPV1 virion-infected S. cerevisiae culture. Northern blot hybridization showed that viral RNA was detected in long-term BPV1-infected S. cerevisiae cultures (82-108 days). The levels of the viral RNA transcription varied significantly over the long time period, which showed active transcription at an early stage (Day 3 to Day 16), weak transcription at a middle stage (Day 23 to Day 45) and stable transcription at the late stage of culture (Day 55 to Day 82/85/95). Three major BPV1 transcripts of 4.3, 2.6 and 1.8 Kb were identified, with 4.3 Kb a minor transcript and the 1.8 Kb the most prominent transcript compared with the 2.6 Kb species. Immunoblotting showed that L1 capsid protein was expressed, with its variable amounts corresponding to the levels of RNA transcription over the time period. 35S-methionine/cysteine labeling and immunoprecipitation proved that the detected L1 protein was newly synthesized in BPV1-infected S. cerevisiae cultures. 33.3-54.2% of the cell colonies expressed L1 protein. Thus, the S. cerevisiae system, as a promising model, may be used not only for the study of virus like particle formation of BPV1 in vitro, but also for further functional analysis of individual viral genes in BPV1 life cycle. Keywords: BPV1; viral RNA transcription; expression of L1 capsid protein; virion-infected Saccharomyces cerevisiae.

[Expression and significance of NF-κB and MIF in lung tissue of silicon-stained rats].

OBJECTIVE: To investigate the distribution and expression of nuclear transcription factor(NF-κB) and macrophage migration inhibitory factor(MIF) in the lung tissue of rats exposed to silica. METHODS: Atotal of sixty-four adult rats aged 10 to 12 weeks(cleaning grade) were randomly divided into control group and silica dust group(32 rats each). At day 3, 7, 14, and 28 after modeling, 8 rats were randomly sacrificed in each group. Immunohistochemistry was used to detect the distribution and expression of NF-B and MIF in lung tissue. RESULTS: The positive result of NF-κB p65 were localized in the nucleus and cytoplasm, and were mainly expressed in bronchial wall epithelial cells, macrophages, neutrophils, lung mesenchymal cells, and alveolar epithelial cells. The IOD value of NF-κB p65 in the dust-exposed group was compared with the control group at each time point, and the difference was statistically significant(P<0. 05). The result of MIF immunohistochemistry in rat lung tissue showed that: MIF-positive cells were mainly alveolar epithelial cells, mesenchymal macrophages and alveolar macrophages. Among them, positive expression was also found in part of the capillary endothelium, and in smooth muscle cells of the vessel wall There is also a small amount of expression. The MIF IOD value of the dust-exposed group was compared with the control group at each time point, and the difference was statistically significant(P<0. 05). CONCLUSION: Both NF-κB and MIF are positively expressed in the lung tissue of silica-exposed rats, which has certain reference significance in the early diagnosis and treatment of silicosis in the future.

Application of combined porous tantalum scaffolds loaded with bone morphogenetic protein 7 to repair of osteochondral defect in rabbits.

PURPOSE: Porous tantalum (PT) has been widely used in orthopaedic applications for low modulus of elasticity, excellent biocompatibility, and the microstructures similar to cancellous bone. In order to improve the biological activity of PT, biologically active factors can be combined with the material. The purpose of this study was to investigate if bone morphogenetic protein 7 (BMP-7) modifications could enhance the repairing of cartilage of PT in osteochondral defect in medial femoral condyle of rabbits. METHODS: A cylindrical osteochondral defect model was created on the animal medial femoral condyle of and filled as follows: PT modified with BMP-7 for MPT group, non-modified PT for the PT group, while no implants were used for the blank group. The regenerated osteochondral tissue was assessed and analyzed by histological observations at four, eight and 16 weeks post-operation and evaluated in an independent and blinded manner by five different observers using a histological score. Osteochondral and subchondral bone defect repair was assessed by micro-CT scan at 16 weeks post-operation, while the biomechanical test was performed at 16 weeks post-operation. RESULTS: Briefly, higher overall histological score was observed in the MPT group compared to PT group. Furthermore, more new osteochondral tissue and bone formed at the interface and inside the inner pores of scaffolds of the MPT group compared to PT group. Additionally, the micro-CT data suggested that the new bone volume fractions and the quantity and quality of trabecular bone, as well as the maximum release force of the bone, were higher in the MPT group compared to PT group. CONCLUSIONS: We demonstrated that the applied modified PT with BMP-7 promotes excellent subchondral bone regeneration and may serve as a novel approach for osteochondral defects repair.

Enhanced repair of segmental bone defects in rabbit radius by porous tantalum scaffolds modified with the RGD peptide.

Fast and stable repair of segmental bone defects remains a challenge for clinical orthopedic surgery. In recent years, porous tantalum has been widely applied in clinical orthopedics for low modulus of elasticity, with three-dimensional microstructures similar to cancellous bone and excellent biocompatibility. To further improve bone the repairing ability of porous tantalum, the cyclo(-RGDfK-) peptide was coated on the surface of porous tantalum scaffolds. A model of 15 mm segmental defect was made at the midshaft of right radius in New Zealand White rabbits. In the experimental group, defects were implanted (press-fit) using porous tantalum scaffolds modified with cyclo(-RGDfK-) peptide. Control animals were implanted with non-modified porous tantalum scaffolds or xenogeneic cancellous bone scaffolds, respectively. No implant was provided for the blank group. Bone repair was assessed by X-ray and histological observations at 4, 8, and 16 weeks post-operation, with biomechanical tests and micro-computed tomography performed at 16 weeks post-surgery. The results showed that bone formation was increased at the interface and inside the inner pores of modified porous tantalum scaffolds than those of non-modified porous tantalum scaffolds; biomechanical properties in the modified porous tantalum group were superior to those of the non-modified porous tantalum and xenogeneic cancellous bone groups, while new bone volume fractions using micro-computed tomography analysis were similar between the modified porous tantalum and xenogeneic cancellous bone groups. Our findings suggested that modified porous tantalum scaffolds had enhanced repairing ability in segmental bone defect in rabbit radius, and may serve as a potential material for repairing large bone defects.

The effect of non-growth factors on chondrogenic differentiation of mesenchymal stem cells.

Chondrogenic differentiation of mesenchymal stem cells (MSCs) in vitro usually requires the presence of growth factors in the culture condition. But many cost-effect methods can successfully fulfill this without addition of these cytokines. This article focuses upon the effect of non-growth factors on the chondrogenic differentiation of MSCs and the concise introduction of the potential mechanism of these methods.

[Assessing drug targeting of Yougui Pill, Zuogui Pill, and their disassembled prescriptions using infrared thermography].

OBJECTIVE: To dynamically assess drug targeting of Yougui Pill (YP) and Zuogui Pill (ZP) using infrared thermography. METHODS: In this self-control experiment, five healthy volunteers were recruited. By using infrared thermography 10 to 11 thermal images of different body locations were taken from each participant after they took warm water, YP, ZP, and their dissembled prescriptions at 30, 70, 100, 130, and 160 min, respectively. The heat values in the lower quadrant abdomen, uterus, Du channel, and Shenque (CV8) were statistically analyzed after scanning for 125 times. RESULTS: Administration of YP and its disassembled prescriptions enhanced the heat value of the locations of the Du channel and Shenque (CV8), but did no enhance the heat value of the lower quadrant abdomen at 30 min. Administration of ZP and its disassembled prescriptions reduced the heat value in the locations of the lower quadrant abdomen, uterus, Du channel, and Shenque (CV8) at each time point. CONCLUSION: The drug targeting of ZP and YP focused on the locations of the Du channel and Shenque (CV8), not on the locations of the lower quadrant abdomen or uterus.

An EMT-based gene signature enhances the clinical understanding and prognostic prediction of patients with ovarian cancers.

BACKGROUND: Ovarian cancer (OC) is one of the most common gynecological cancers with malignant metastasis and poor prognosis. Current evidence substantiates that epithelial-mesenchymal transition (EMT) is a critical mechanism that drives OC progression. In this study, we aspire to identify pivotal EMT-related genes (EMTG) in OC development, and establish an EMT gene-based model for prognosis prediction. METHODS: We constructed the risk score model by screening EMT genes via univariate/LASSO/step multivariate Cox regressions in the OC cohort from TCGA database. The efficacy of the EMTG model was tested in external GEO cohort, and quantified by the nomogram. Moreover, the immune infiltration and chemotherapy sensitivity were analyzed in different risk score groups. RESULTS: We established a 11-EMTGs risk score model to predict the prognosis of OC patients. Based on the model, OC patients were split into high- and low- risk score groups, and the high-risk score group had an inevitably poor survival. The predictive power of the model was verified by external OC cohort. The nomogram showed that the model was an independent factor for prognosis prediction. Moreover, immune infiltration analysis revealed the immunosuppressive microenvironment in the high-risk score group. Finally, the EMTG model can be used to predict the sensitivity to chemotherapy drugs. CONCLUSIONS: This study demonstrated that EMTG model was a powerful tool for prognostic prediction of OC patients. Our work not only provide a novel insight into the etiology of OC tumorigenesis, but also can be used in the clinical decisions on OC treatment.

Identification and validation of a gene-based signature reveals SLC25A10 as a novel prognostic indicator for patients with ovarian cancer.

BACKGROUND: Ovarian cancer is a common gynecological cancer with poor prognosis and poses a serious threat to woman life and health. In this study, we aimed to establish a prognostic signature for the risk assessment of ovarian cancer. METHODS: The Cancer Genome Atlas (TCGA) dataset was used as the training set and the International Cancer Genome Consortium (ICGC) dataset was set as an independent external validation. A multi-stage screening strategy was used to determine the prognostic features of ovarian cancer with R software. The relationship between the prognosis of ovarian cancer and the expression level of SLC25A10 was selected for further analysis. RESULTS: A total of 16 prognosis-associated genes were screened to construct the risk score signature. Survival analysis showed that patients in the high-risk score group had a poor prognosis compared to the low-risk group. Accuracy of this prognostic signature was confirmed by the receiver operating characteristic (ROC) curve and decision curve analysis (DCA), and validated with ICGC cohort. This signature was identified as an independent factor for predicting overall survival (OS). Nomogram constructed by multiple clinical parameters showed excellent performance for OS prediction. Finally, it's found that patients with low expression of SLC25A10 generally had poor survival and higher resistance to most chemotherapeutic drugs. CONCLUSIONS: In sum, we developed a 16-gene prognostic signature, which could serve as a promising tool for the prognostic prediction of ovarian cancer, and the expression level of SLC25A10 was tightly associated with OS of the patients.

Middle Miocene lotus (Nelumbonaceae, Nelumbo) from the Qaidam Basin, Northern Tibet Plateau.

The Neogene environment and paleovegetation of today's semi-arid and arid Central Asia remain elusive. Little is known about the effect of paleoclimatic change on the distribution and ecological response mechanisms of aquatic plants, especially on the Tibetan Plateau. Here, we report a new species of Nelumbo Adanson, including leaves, receptacles, and fruits, namely Nelumbo delinghaensis sp. nov., from the Upper Youshashan Formation of the upper Middle Miocene in the northern Qaidam Basin on the Tibetan Plateau. The new species comprises centrally peltate leaves with 12−15 actinodromous primary veins and a receptacle embedded with ca. 15−30 fruits, with an unlobed central disc. Megafossils of lotus from northwest China broaden the geographical and stratigraphic ranges of Nelumbo. Our findings suggest that a large freshwater lake body surrounded by temperate forests and grassland developed in the Qaidam Basin during the late Middle Miocene, in sharp contrast to the present desert vegetation. The climate used to be sufficiently warm and moist enough to support a forest-steppe ecosystem with abundant freshwater bodies.

Significant growth inhibition by a bispecific affibody targeting oncoprotein E7 in both HPV16 and 18 positive cervical cancer in vitro and in vivo.

The infection with HPV 16 and 18 high-risk types account for more than 80 % of cervical cancer incidence, but there is still no targeted agent against HPV for cervical cancer therapy. Our previous study constructed a bispecific affibody Z16-18 targeting HPV16 and 18 early antigen 7 (E7, responsible for the infected cell malignant transformation). In the present study, we prepared Z16-18 in prokaryotic expression system and confirmed its significant growth inhibition both on SiHa (HPV16 positive) and HeLa (HPV18 positive) cervical cancer cells by arresting cell cycle at G0/G1 phase. The IC50 of Z16-18 on SiHa and HeLa were close in value. Z16-18 could specifically target E7 in both SiHa and HeLa, and exhibited prominent targeted enrichment on tumor tissues derived from SiHa or HeLa, resulting in the inhibition of tumourigenesis and tumour growth in vivo. Furthermore, Z16-18 could inhibit the interaction between E7 and pRb to block the E7-pRb carcinogenic pathway, resulting in the decreased release of E2F and the cell growth inhibition characterized by the decrease of CDK6 and Cyclin D1. This study provides a new strategy for targeted therapy based on affibody, and Z16-18 has great potential for utilisation and development as an agent targeting HPV16 and HPV18 related cervical cancer.

Characterization of Episomal Replication of Bovine Papillomavirus Type 1 DNA in Long-Term Virion-Infected Saccharomyces Cerevisiae Culture.

We have previously reported that bovine papillomavirus type 1 (BPV-1) DNA can replicate its genome and produce infectious virus-like particles in short term virion-infected S. cerevisiae (budding yeast) cultures (Zhao and Frazer 2002, Journal of Virology, 76:3359-64 and 76:12265-73). Here, we report the episomal replications of BPV-1 DNA in long term virion-infected S. cerevisiae culture up to 108 days. Episomal replications of the BPV-1 DNA could be divided into three patterns at three stages, early active replication (day 3-16), middle weak replication (day 23-34/45) and late stable replication (day 45-82). Two-dimensional gel electrophoresis analysis and Southern blot hybridization have revealed further that multiple replication intermediates of BPV-1 DNA including linear form, stranded DNA, monomers and higher oligomers were detected in the virion-infected yeast cells over the time course. Higher oligomers shown as covalently closed circular DNAs (cccDNAs) are the most important replication intermediates that serve as the main nuclear transcription template for producing all viral RNAs in the viral life cycle. In this study, the cccDNAs were generated at the early active replication stage with the highest frequencies and then at late stable replication, but they appeared to be suppressed at the middle weak replication. Our data provided a novel insight that BPV-1 genomic DNA could replicate episomally for the long period and produce the key replication intermediates cccDNAs in S. cerevisiae system.

[Experimental study on tissue engineering platelet lysates in the promotion of bone reconstruction].

OBJECTIVE: To evaluate the effects of tissue engineered allogeneic platelet lysates (PL) upon bone reconstruction. METHODS: After preparation of recombinant material with PL, allogeneic decalcified bone granules (ADBG) and collagen type I (CG), 30 healthy Wistar rats were used to prepare the bilateral bone defects in femoral condyles. The defects were filled with equivalent PL/ADBG/CG, ADBG/CG and CG in different groups of A, B and C (with 10 rats each) respectively. At 4 weeks, the defect reconstruction was evaluated with radiology, histology, immunology and biomechanics. RESULTS: (1) The X-ray showed that bone density in group A (4.18 +/- 0.96) was close to that of normal bone and it was significantly higher than that in group B (2.36 +/- 0.87) and group C (1.09 +/- 0.55) (P < 0.01). (2) In comparisons with B and C, the histological assay revealed that there were markedly more activities of new bone formation and more implanted bone granules surviving without significant lymphocyte infiltration, as well as more osteoclastic bone resorption in group A. The bone histomorphometric assay showed the newly formed bone area in group A (286.73 +/- 17.22) was significantly higher than that in group B (94.34 +/- 33.56) and group C (19.12 +/- 14.53) (P < 0.01). (3) Anti-press mechanical measures showed that the destructive load in A, B, C and normal control group was 259.63 +/- 34.57, 187.90 +/- 21.07, 91.33 +/- 26.58 and 311.93 +/- 82.45 respectively. The destructive energy in A, B, C and normal control group was 10.82 +/- 1.44, 7.83 +/- 0.88, 3.81 +/- 1.11 and 12.97 +/- 3.43 respectively. These results showed either destructive load or destructive energy in group A was markedly higher than that in group B and group C with significant difference (P < 0.01), but still lower than that in normal controls (P < 0.01). (4) Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3+CD4+CD8-, CD3+CD8+CD4- and the ratio of CD4/CD8 showed no significance difference within these three groups as well as normal controls. CONCLUSION: Tissue engineering PL (PL/ADBG/CG) is capable of accelerating the regenerative repair of bone defect and promoting the bone regeneration and osetointergretion of allograft bone after transplantation.

[Repair of segmental bone defects in rabbits' radius with domestic porous tantalum encapsulated with pedicled fascial flap].

Objective: To investigate the effect of domestic porous tantalum encapsulated with pedicled fascial flap on repairing of segmental bone defect in rabbits' radius. Methods: A total of 60 New Zealand white rabbits (aged 6- 8 months and weighing 2.5-3.0 kg) were randomly divided into the experimental group and control group (30 rabbits each group). A 1.5 cm segmental bone defect in right radius was established as the animal model. The porous tantalums encapsulated with pedicled fascial flaps (30 mm×20 mm) were implanted in the created bone defect in the experimental group, and the porous tantalums were only implanted in the control group. X-ray films were observed at the day after operation and at 4, 8, and 16 weeks after operation. Specimens were taken out at 4, 8, and 16 weeks after operation for HE staining and toluidine blue staining observation. The maximum load force and bending strength were detected by three point bending biomechanical test, and the Micro-CT analysis and quantitative analysis of the new bone volume fraction (BV/TV) were performed at 16 weeks after operation to compare the bone defect repair ability in vivo in 2 groups. Results: All incisions healed by first intention without wound infection. At 4, 8, and 16 weeks after operation, the X-ray films showed that the implants were well maintained without apparent displacement. As followed with time, the combination between the implants and host bone became more and more closely, and the fracture line gradually disappeared. HE staining and toluidine blue staining showed that new bone mass and maturity gradually increased at the interface and inside materials in 2 groups, and the new bone gradually growed from the interface to internal pore. At 16 weeks after operation, the three point bending biomechanical test showed that the maximum load force and bending strength in the experimental were (96.54±7.21) N and (91.26±1.76) MPa respectively, showing significant differences when compared with the control group [(82.65±5.65) N and (78.53±1.16) MPa respectively] ( t=3.715, P=0.004; t=14.801, P=0.000). And Micro-CT analysis exhibited that there were a large amount of new bone at the interface and the surface of implant materials and inside the materials. The new bone BV/TV in the experimental group (32.63%±3.56%) was significantly higher than that in control group (25.07%±4.34%) ( t=3.299, P=0.008). Conclusion: Domestic porous tantalum encapsulated with pedicled fascial flap can increase local blood supply, strengthen material bone conduction ability, and promote the segmental bone defect repair.

A modified molecular framework derived highly efficient Mn-Co-carbon cathode for a flexible Zn-air battery.

A controllable Co doping strategy is introduced to significantly activate more catalytic sites for Mn-based materials and anchor Co-Mn nanoparticles on the N-doped carbon nanotube (N-CNT) substrates. The as-synthesized CoMn2O4/N-CNTs exhibit excellent ORR catalytic performance with large limited current density and positive half-wave potential, even outperforming the Pt/C catalysts. The outstanding ORR activity allows the CoMn2O4/N-CNTs to directly serve as the cathode electrode in a liquid/solid state Zn-air battery, demonstrating large power density and robust stability.

[Role of AcSDKP on collagen synthesis and degradation in cultured rat cardiac fibroblast].

OBJECTIVE: To investigate the role of AcSDKP on collagen synthesis and degradation in cultured rat cardiac fibroblasts. METHODS: Neonatal rat cardiac fibroblasts were isolated and stimulated by PDGF. The cell proliferation was observed by (3)H-TdR incorporation assay. The synthesis of collagen was measured by (3)H-proline incorporation assay. The expression of type I and type III collagen and MMP-1 protein were measured by Western blot. The MMP-2 and MMP-9 activity was evaluated with zymography assay. RESULTS: PDGF stimulated cardiac fibroblasts proliferation with increased collagen synthesis and type I and type III collagen protein expressions as well as MMP-2 and MMP-9 activities and MMP-1 expression. AcSDKP inhibited cardiac fibroblasts proliferation induced by PDGF and reduced collagen synthesis and type I and type III collagen protein expression. AcSDKP also further up-regulated MMP-2 and MMP-9 activities and MMP-1 expression in cardiac fibroblasts induced by PDGF. CONCLUSION: AcSDKP inhibited proliferation and collagen synthesis and up-regulated matrix metalloproteinases activity or expression induced by PDGF, which was possibly related with the effect of AcSDKP anti-fibrosis.

[Domestic porous tantalum loaded with bone morphogenetic 7 in repairing osteochondral defect in rabbits].

OBJECTIVE: ?To investigate the ability to repair osteochondral defect and the biocompatibility of porous tantalum loaded with bone morphogenetic protein 7 (BMP-7) by observing the effect of porous tantalum loaded with BMP-7 in repairing articular cartilage and subchondral bone defect. METHODS: ?The cartilage defect models of medial femoral condyle were established in 48 New Zealand white rabbits, which were randomly divided into 3 groups (n=16): porous tantalum material+BMP-7 (group A) and porous tantalum material (group B) were implanted into the right side of the medial femoral condyle; and no material was implanted as control (group C). The general condition of animals was observed after operation, then the specimens were harvested for gross observation, histological observation, and scanning electron microscope (SEM) observation at 4, 8, and 16 weeks after implantation, micro-CT was used to observe the cartilage and bone ingrowth and bone formation around porous tantalum at 16 weeks after implantation. RESULTS: ?No animal died after operation and wound healed well. Gross observation showed that defects of groups A and B were covered with new cartilage with time, but earlier new cartilage formation and better repair were observed in group A than group B, no repair occurred at the site of bone defects, and defect surface was filled with fibrous tissue in group C. Cartilage repair gross score of group A was significantly higher than that of group B at 8 and 16 weeks (P<0.05) but no significant difference was found between groups A and B at 4 weeks (P>0.05). SEM observation showed that the number of new cartilage and osteoblasts increased gradually with time, and the implanted material was gradually covered with the extracellular matrix, and the new bone tissue grew into the pores of the material; the neonatal bone tissue and extracellular matrix secretion of group A were significantly more than those of group B. The toluidine blue staining results showed that new cartilage and bone tissue gradually increased in the porous tantalum interface, and new bone trabecula formed and grew in the pores, the bone and the porous tantalum contact tended to close, and cartilage defect was gradually covered with cartilage like tissue, cartilage tissue and porous tantalum combined more closely in groups A and B at 4, 8 and 16 weeks. New cartilage and bone tissue of group A was more than that of group B. Micro-CT analysis indicated that the bone mineral density, trabecular thickness, trabecular number, and bone volume fraction of group A were significantly higher than those of group B at 16 weeks (P<0.05), but the trabecular bone space was significantly lower than that of group B (P<0.05). CONCLUSIONS: ?The domestic porous tantalum has good biocompatibility, domestic porous tantalum loaded with BMP-7 can promote the formation of a stable connection with the host and has a good effect on cartilage and subchondral bone defect repair.

Biocompatibility and osteogenic properties of porous tantalum.

Porous tantalum has been reported to be a promising material for use in bone tissue engineering. In the present study, the biocompatibility and osteogenic properties of porous tantalum were studied in vitro and in vivo. The morphology of porous tantalum was observed using scanning electron microscopy (SEM). Osteoblasts were cultured with porous tantalum, and cell morphology, adhesion and proliferation were investigated using optical microscopy and SEM. In addition, porous tantalum rods were implanted in rabbits, and osteogenesis was observed using laser scanning confocal microscopy and hard tissue slice examination. The osteoblasts were observed to proliferate over time and adhere to the tantalum surface and pore walls, exhibiting a variety of shapes and intercellular connections. The porous tantalum rod connected tightly with the host bone. At weeks 2 and 4 following implantation, new bone and small blood vessels were observed at the tantalum-host bone interface and pores. At week 10 after the porous tantalum implantation, new bone tissue was observed at the tantalum-host bone interface and pores. By week 12, the tantalum-host bone interface and pores were covered with new bone tissue and the bone trabeculae had matured and connected directly with the materials. Therefore, the results of the present study indicate that porous tantalum is non-toxic, biocompatible and a promising material for use in bone tissue engineering applications.

Stem cells derived from human first-trimester umbilical cord have the potential to differentiate into oocyte-like cells in vitro.

Compared to stem cells derived from human term umbilical cord, stem cells derived from human first-trimester umbilical cord (hFTUC) exhibit a significantly greater proliferative potential, and more efficiency in terms of their in vitro differentiation. In the present study, we investigated whether hFTUC-derived stem cells are able to differentiate into germ cells. The hFTUC-derived stem cells were first isolated, expanded and then cultured in differentiation medium containing human follicular fluid, follicle-stimulating hormone (FSH)/luteinizing hormone (LH) and estradiol for 24 days. During the period of induction, a subpopulation of the cultured cells appeared that had a morphological resemblance to primordial germ cells (PGCs) and cumulus-oocyte complex (COC)-like cells, and oocyte-like cells (OLCs). The PGC-like cells expressed specific markers indicative of germ cell formation such as octamer-binding transcription factor 4 (OCT4), stage-specific embryonic antigen 1 (SSEA1), B lymphocyte-induced maturation protein-1 (Blimp1), PR domain containing 14 (Prdm14), transcription factor AP-2 gamma (Tfap2C), VASA, STELLA, deleted in azoospermia-like (DAZL) and interferon-induced transmembrane protein 3 (IFITM3). The OLCs, which contained a single germinal vesicle, expressed oocyte-specific markers, such as synaptonemal complex protein 3 (SCP3), growth/differentiation factor-9 (GDF9), GDF9B and zona pellucida (ZP)1, ZP2 and ZP3. The COC-like cells secreted estradiol, vascular endothelial growth factor and leukemia inhibitory factor. Thus, our findings suggest that hFTUC-derived stem cells have an intrinsic ability to differentiate into OLCs, which may provide an in vitro model for the identification of factors involved in germ cell formation and differentiation.