Current advances for bone regeneration based on tissue engineering strategies / 医学前沿

Bone tissue engineering (BTE) is a rapidly developing strategy for repairing critical-sized bone defects to address the unmet need for bone augmentation and skeletal repair. Effective therapies for bone regeneration primarily require the coordinated combination of innovative scaffolds, seed cells, and biological factors. However, current techniques in bone tissue engineering have not yet reached valid translation into clinical applications because of several limitations, such as weaker osteogenic differentiation, inadequate vascularization of scaffolds, and inefficient growth factor delivery. Therefore, further standardized protocols and innovative measures are required to overcome these shortcomings and facilitate the clinical application of these techniques to enhance bone regeneration. Given the deficiency of comprehensive studies in the development in BTE, our review systematically introduces the new types of biomimetic and bifunctional scaffolds. We describe the cell sources, biology of seed cells, growth factors, vascular development, and the interactions of relevant molecules. Furthermore, we discuss the challenges and perspectives that may propel the direction of future clinical delivery in bone regeneration.

Investigation on the detection of transient ischemic attack in cerebrovascular disease surveillance in Hunan Province / 中华健康管理学杂志

Objective To determine the incidence and prevalence of transient ischemic attack (TIA) and to evaluate its epidemiological situation in Hunan province.Methods Seven monitoring points were randomly selected from the province,a total of 8 311 subjects aged≥50 years were then chosen by stratified sampling.The cases counted in prevalence was defined as patients diagnosed before 24:00 o'clock August 31st,2013,and the new diagnosis for incident counting was defined as those diagnosed between 00:00 September 1st,2012 and 24:00 August 31st,2013.Results Among all 8 311 screened subjects,the number of TIA patients was 24 (288.8 per 100 000 people),the incidence of TIA was 7 (85.2 per 100 000 people).Standardized prevalence and incidence were 283.2 and 82.4 per 100 000 respectively using 2010 China census population.Among them,the standardized incidence rate of female was higher than that of male (114.8 per 100 000 person-years vs.48.8 per 100 000 person-years),and the prevalence rate of males was higher than that of female (288.2 per 100 000 people vs.273.2 per 100 000 people).Hypertension is the most important risk factor for TIA (55.2％).Conclusion The incidence and prevalence of TIA in Hunan province are higher than the national average.Hypertension is the main risk factor.

Working conditions of bipolar radiofrequency on human articular cartilage repair following thermal injury during arthroscopy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The thermal injury during bipolar radiofrequercy results in chondrocyte death that limits cartilage repair. The purpose was to determine the effects of various factors of bipolar radiofrequency on human articular cartilage after thermal injury, offering suitable working conditions for bipolar radiofrequency during arthroscopy.</p><p><b>METHODS</b>Osteochondral explants from 28 patients undergoing total knee arthroplasty (TKA) in Department of Orthopaedic, Peking University Reople's Hospital from October 2013 to May 2014, were harvested and treated using bipolar radiofrequency in a light contact mode under the following conditions: various power setting of levels 2, 4 and 6; different durations of 2 seconds, 5 seconds and 10 seconds; irrigation with fluids of different temperatures of 4°C, 22°C, and 37°C; two different bipolar radiofrequency probes ArthroCare TriStar 50 and Paragon T2. The percentage of cell death and depth of cell death were quantified with laser confocal microscopy. The content of proteoglycan elution at different temperatures was determined by spectrophotometer at 530 nm.</p><p><b>RESULTS</b>Chondrocyte mortality during the treatment time of 2 seconds and power setting of level 2 was significantly lower than that with long duration or in higher level groups (time: P = 0.001; power: P = 0.001). The percentage of cell death after thermal injury was gradually reduced by increasing the temperature of the irrigation solutions (P = 0.003), the depth of dead chondrocytes in the 37°C solution group was significantly less than those in the 4°C and 22°C groups (P = 0.001). The proteoglycan elution was also gradually reduced by increasing the temperature (P = 0.004). Compared with the ArthroCare TriStar 50 group, the percentage of cell death in the Paragon T2 group was significantly decreased (P = 0.046).</p><p><b>CONCLUSIONS</b>Thermal chondroplasty with bipolar radiofrequency resulted in defined margins of chondrocyte death under controlled conditions. The least cartilage damage during thermal chondroplasty could be achieved with lower power, shorter duration, suitable temperature of irrigation solutions and chondroprotective probes. The recommendations for the use of bipolar radiofrequency to minimize cartilage damage could be achieved with a power setting of level 2, treatment duration of 2 seconds, suitable fluid temperature (closer to body temperature of 37°C) and chondroprotective Paragon T2 probes.</p>

Construction of scFv antibody mini-library to 3 cellular surface molecules / 生物医学工程学杂志

To construct a scFv antibody mini-library by phage display technique from the spleen cells of BALB/c mice immunized with extracellular domain of N-cadherin (N-cad), CD34 and AC133, the extracellular domain genes of N-cad, CD34 and AC133 were cloned into a phagemid pSEX81 respectively, and were then displayed on the phagemid in the form of fusion protein with p III protein. After being effectively immunized with the fusion protein, the spleen of the mice were harvested, and total RNA were extracted from the spleen. The cDNA of VH and VL genes were amplified by RT-PCR, and a scFv-phage display antibody library was constructed with the amplified V-genes. The content, multiplicity and expressing potential of the library were examined. As a result, we had produced a scFv library containing 1.4 x 10(6) individual clones which showed different patterns after being digested with restriction endoneuclease Mua I. The surface display expression of the library was also verified. It indicated that the capacity and diversity of the library was sufficient for screening specific scFv antibody against N-cad, CD34 and AC133. The library will be useful for isolating corresponding specific scFv antibodies.

Study on Diagnosis of Schistosomiasis by ELISA Using Periodate-treated Soluble Egg Antigen / 中国寄生虫学与寄生虫病杂志

0. 05) and the specificity is higher than that of the SEA-ELISA (P

Isolation and expression of N-cadherin extracellular domain / 中国病理生理杂志

AIM: To clone the extracellular domain of N-cadherin cDNA, and to observe the antigenicity of the expressed protein. METHODS: Total RNA was extracted from CD34+ cells separated from fetal liver and bone marrow cells. The extracellular domain of N-cad cDNA was amplified with RT-PCR and inserted into a vector pOPE101-215. The recombinant pOPE-N-cad was expressed with IPTG induction. Then, mice were immunized with the protein. RESULTS: The extracellular domain of N-cad cDNA from CD34+ cells was identified by DNA sequencing. The recombinant pOPE-N-cad in host XL1-blue expressed a 70 kD protein after induced with IPTG, and anti-N-cad antibody was detected in serum of the immunized mice after 5 times injection of the recombinant N-cad protein. CONCLUSION: CD34+ cells bore N-cad gene and the recombinant protein of the extracellular domain of N-cad cDNA shows good immunogenicity.