BACKGROUND: Epidermal stem cell as a specific stem cell in skin tissue, not only plays an important role in maintaining the metabolism of skin, but also closely related to wound repair, is the basis of occurrence of skin and its appendages.OBJECTIVE: To summarize the research status on features and application of epidermal stem cells in recent years.METHODS: A computer-based online search was conducted in PubMed Database and CNKI Database with the key words of "epidermal stem cell, basic study, gene therapy" from June to August, 2009.RESULTS AND CONCLUSION: 532 articles were received in the first round, including 283 in Chinese and 249 in English. Articles which were unrelated articles (n=127), repeated research (n=158), and Meta analysis (n=25) were excluded. A total of 31 articles were reserved for review. Epidermal stem cell had the typical characteristics of long periodicity in vivo, self- renew capacity and easy to adherent to skin basement membrane. They had constant position in tissues which were located in basal layer and hair follicle bulge with rich blood supply in epidermis. The proliferation and differentiation of epidermal stem cells were affected by external and internal factors. The former meant microenvironment which stem cell existed in, that was called "Niche" of stem cell; the latter included integrin-mitogen-activated protein kinase pathway, Wnt signaling pathway, c-Myc proto-oncogene, and Notch signaling pathway. Currently, common marker of epidermal stem cells includes integrin, keratin, p63, p75, and epidermal cell-surface transferrin receptor CD71, etc. Epidermal stem cells can be explored in tissue engineering and wound repair, gene therapy, epidermal tumors, etc.

BACKGROUND: Epidermal stem cell as a specific stem cell in skin tissue, not only plays an important role in maintaining the metabolism of skin, but also closely related to wound repair, is the basis of occurrence of skin and its appendages. OBJECTIVE: To summarize the research status on features and application of epidermal stem cells in recent years. METHODS: A computer-based online search was conducted in PubMed Database and CNKI Database with the key words of "epidermal stem cell, basic study, gene therapy" from June to August, 2009. RESULTS AND CONCLUSION: 532 articles were received in the first round, including 283 in Chinese and 249 in English. Articles which were unrelated articles (n=127), repeated research (n=158), and Meta analysis (n=25) were excluded. A total of 31 articles were reserved for review. Epidermal stem cell had the typical characteristics of long periodicity in vivo, self-renew capacity and easy to adherent to skin basement membrane. They had constant position in tissues which were located in basal layer and hair follicle bulge with rich blood supply in epidermis. The proliferation and differentiation of epidermal stem cells were affected by external and internal factors. The former meant microenvironment which stem cell existed in, that was called "Niche" of stem cell; the latter included integrin-mitogen-activated protein kinase pathway, Wnt signaling pathway, c-Myc proto-oncogene, and Notch signaling pathway. Currently, common marker of epidermal stem cells includes integrin, keratin, p63, p75, and epidermal cell-surface transferrin receptor CD71, etc. Epidermal stem cells can be explored in tissue engineering and wound repair, gene therapy, epidermal tumors, etc.

Objective To explore the methods of culture and identification of human placental microvascular endothelial cells(HPMVEC) in vitro,aiming to construct the polar model of human placental barrier.Methods By proteolytic enzymes,the tissular and cellular suspensions were collected from the chorionic villi of pregnant and centrifugated over a preformed discontinuous Percoll gradient.The highly purified human placental microvascular endothelial cells were obtained and cultured in HG-DMEM with fetal calf serum and identified by immunocytochemistry(SP methods) and transmission electron microscope.Results The highly purified human microvascular endothelial cells were cultured in vitro and passaged for three to five generations.Factor Ⅷ-related antigen and CD34 were both positive by immunocytochemistry.Weibel-Palade body(W-P body) was observed by transmission electron microscope.Conclusion Human placental microvascular endothelial cells can be isolated and cultured successfully in vitro by our method.

Objective To investigate the clinical value of thromboelastogram(TEG) in predicting the deep venous thrombosis(DVT) formation of bedridden senile patients and further explore the risk factors for hypercoagulability in those patients.Methods Patients lying on bed for at least 1 year because of alzheimer's disease,stroke and fracture,aged between 70 to 90 years old,were selected in the Geriatrics Department of Shougang Hospital of Peking University from February 2013 to February 2014.Those patients were divided by Clotting composite index(CI) measured with TEG,CI less than and equal to 3 was control group,CI more than 3 was hypercoagulable group.The patients were followed-up for one year to identify the formation of DVT.Logistic regression analysis was used to analyze the independent risk factors of elderly patients with high blood coagulation state in bed.Results Two groups of baseline blood clots elastic graph indicators:Angle(α) of solidification,CI,coagulation time(K),the biggest thrombosis(MA),blood coagulation reaction time(R) comparative differences were statistically significant(P<0.05).In view of the bedridden elderly patients of high coagulation state,according to the result of single factor analysis of related factors,high coagulation state revealed with age(P=0.047),history of diabetes(P=0.001),bed time(P=0.043),tumor(P=0.001),fracture(P=0.002),but unrelated with sex,blood lipids,blood pressure,alcohol consumption,left ventricular ejection fraction.The multivariate logistic regression analysis indicated that fracture(OR(95%CI):5.634(1.114~28.496),P=0.037),tumor(OR(95%CI):4.652(1.142~18.955),P=0.032) and diabetes mellitus(OR(95%CI):6.269(1.528~25.725),P=0.011) were independent risk factors for DVT.Conclusion The incidence of DVT in bedridden senile patients with hypercoagulability identified by CI is higher than those with normal coagulability.Tumor,fracture and diabetes mellitus are independent risk factors for DVT.

Objective:To compare the efficacy and safety between microvascular anastomostive device (MAD) and hand-sewn (HS) in free flap reconstruction.Methods:Databases in Pubmed, Embase, CNKI, Wanfang, CBM and Weipu etc. The comparative study of MAD device and manual suture in free flap repair of soft tissue defects published in domestic and foreign official journals from January, 1950 to October, 2019 was collected. The quality of the included studies was strictly evaluated and relevant data were extracted. Revman 5.3 software was used to analyze all relevant data.Results:Fifteen trials with 5 539 patients were included. There was significant difference between MAD and HS in time of venous anastomoses ( SMD=-5.46, 95% CI: -7.50, -3.41, P<0.001), time of artery anastomoses ( SMD=-5.16, 95% CI: -9.61, -0.71, P=0.02), vascular crisis ( RR=0.49, 95% CI: 0.34, 0.70, P<0.001) and flap necrosis ( RR=0.52, 95% CI: 0.32, 0.86, P=0.01), the difference between the 2 groups was statistically significant ( P< 0.05). Conclusion:According to the analyses of the pooled results of MAD group and HS group, the data tend to suggest that MAD is superior to HS in the reconstruction with free flap.

Objective To investigate the stability of lumbar single?level dynamicly fixed by socket track pedicle screws after decompression. Methods Socket track pedicle screws are made of titanium?alloy, swing like universal screw within the scope of 18° in the sagittal plane and 8° in the horizontal plane. Motion constraints were due to the hole which the screw goes through. Six pig spines (L1-5) were tested by applying a pure moment of 4.018 Nm in 3 directions of loading. The range of motion (ROM) of the following groups underwent different surgical procedures was measured:(1) intact;(2) dynamic fixation 1 (decompres?sion by total laminectomy and instrumentation with socket track pedicle screws); (3) dynamic fixation 2 (decompression by total laminectomy and bilateral facetectomy while instrumentation with socket track pedicle screws);( 4) instability resulted from decom?pression (decompression by total laminectomy plus bilateral facetectomy without any rod);(5) hybrid fixation (decompression by to?tal laminectomy and bilateral facetectomy while instrumentation with 2 socket track pedicle screws connected with 2 unilateral pedicle screws ). Results Compared with the intact specimens (in flexion, extension, lateral bending and rotation, corresponding angular displacements were 1.84°±0.75°, 1.55°±0.34°, 2.2°±1.07°, 2.06°±0.76° respectively), the ROM of segment L3, 4 of each group were significantly restricted except for axial rotation. In flexion, extension and lateral bending, the ROM was reduced to 0.71°±0.39°, 0.46°±0.18°, 0.85°±0.66° in dynamic fixation 1 group;0.79°±0.43°, 0.71°±0.20°, 1.17°±0.48° in dynamic fixation 2 group and 0.63°±0.50°, 0.37°±0.19°, 0.54°±0.60° in hybrid fixation group. The rotation ROM of dynamic fixation 1 group and hy?brid fixation group were decreased to 1.50°±0.64° and 1.22°±0.36°, whereas the ROM of dynamic fixation 2 had a non?significant reduction to 1.85°±0.67°. The extension and rotation ROM of dynamic fixation 2 increased significantly comparing to dynamic fixa?tion 1 group; the extension, lateral bending and axial rotation ROM of hybrid fixation group were reduced comparing to the state of dynamic fixation 2 group. Conclusion The dynamic instrumentation of single?level lumbar spine with socket track pedicle screws could offer stability in all directions. The flexion, extension, lateral bending and rotation ROM of spine with dynamic instru?mentation after total laminectomy and bilateral facetectomy could be reduced.

Objective To understand the intensity and characteristics of acute toxicity of esculentoside A on mice and measure relevant parameters and observe its diuresis effect on rat. Methods After intraperitoneal injection of different concentrations of esculentoside A to mice, toxic reactions were observed. Rats with water load were intraperitoneally injected with different doses of esculentoside A. Total urine volume in six consecutive hours after the injection was determined. Results The LD50 of esculentoside A calculated by Bliss method was 26. 19 mg · kg-1 , and the 95% confidence interval was 23. 11-29. 85 mg·kg-1 . The mortality and acute toxicity of esculentoside A appeared to be dose-dependent while the blank control group had no abnormal reaction. The urine volume was significantly different between high dose group and the negative control group. No significant difference in urine volume was found between middle and the negative control group, and between low dose group and the negative control group. Conclusion Esculentoside A is poisonous to mice when single dose was intraperitoneally injected, and high dose of esculentoside A has diuresis effect on rat.

Lack of sufficient technical supports for sharing and management of current curriculum resource, which leads to inefficiency in searching curriculum information, has become a common issue in current higher medical education. The key to best use of increasing digital medical teaching resource lies in coping with the problems of sharing and integration. A cloud based storage platform is built to manage the teaching resource of obstetrics, which enables the efficiently sharing and integration of obstetrics related courses. The achievements gained from the platform have demonstrated to improve the work efficacy of teachers and provide students with the opportunity of systematically learning, both of which ultimately con-tribute to the improvement of the quality of theoretical and clinic teaching on obstetrics and gynecology.

We discussed the function of four pairs of genes in the toxin-antitoxin system of Mycobacterium tuberculosis,providing theoretical foundation and scientific basis for studying the transmission mechanism of Mycobacterium tuberculosis.Four pairs of genes which belong to VapBC family,including four VapC genes (Rv1720c,Rv2103c,Rv2494,Rv3408) and four VapB genes (Rv1721c,Rv2104c,Rv2493,Rv3407) were chosen.We constructed a serial of arabinose-induced hybrid plasmid system in Escherichia coli and a serial of acetamide-induced hybrid plasmid system in Mycobacterium smegmatis respectively,in order to observe the potential inhibition effect of VapC and the release inhibition of homologous VapB.Results showed that only one toxin gene(Rv2103c) showed the function of bacteriostasis in both E.coli and M.smegmatis and the homologous antitoxin gene(Rv2104c) could release the inhibition of growth.We built the inducible systems of VapBC family in both E.coli and M.smegmatis respectively and found only a pair of toxin and antitoxin genes(Rv2103c,Rv2104c) had the function of inhibition and release for the growth of bacteria.And two pairs of toxin genes(Rv1720c,Rv2494) did not have the function of inhibition for the growth of both E.coli and M.smegmatis.Whereas,another toxin gene VapC47(Rv3408) also did not have the bacteriostastic activity,only this result was not consistent with the existing literature.We speculated that the reason for this kind of difference may be the different inducible systems we used.Cause the other three results were consistent with all existing literature and the doubtful result also appeared in other reports,so our protocol could be confirmed as reliable,and we would use it to build inducible systems and make further functional identification of certain toxin and antitoxin genes that we are interested in.

Objective To evaluate the effects of the short-term intervention lifestyle intervention on metabolic measurements of community patients with impaired glucose regulation (IGR). Methods A total of 90 IGR participants were randomly assigned to the control group (n=45) or the intervention group (n= 45). The subjects in the control group received routine diet and physical exercise advice once a month. The subjects in the intervention group received additional individualized diet counseling and circuit-type resistance training. Metabolic parameters were compared before or after the intervention between the two groups. Results In oral glucose tolerance test (OGTT),2-h plasma glucose (PG) and homeostasis model of insulin resistance index (HOMA-IR) were significantly decreased in the intervention group at 3 months(F= 13.47 or 82.25 ,both P < 0.05). Body mass index (t=-2.44, P<0.05), systolic blood pressure (t= -3.39, P<0.05), diastolic blood pressure (t=-3.97, P<0.05), fasting plasma glucose (t=-3.89, P<0.05),2-h PG (t=-7.22,P <0.05) ,total cholesterol (t=-2.72,P<0.05),low-density lipoprotein cholesterol (t=-2.74, P<0.05), and glycosylated hemoglobin A1 C (t=-3.73, P<0.05) were significantly declined in the intervention group compared to the control group (all P<0.05). Conclusions Intensive lifestyle intervention can significantly improve the metabolic markers of IGR subjects and should be used to prevent type 2 diabetes.