Mesenchymal stem cells(MSCs)are multipotent stromal cells that possess the capacity for self-renewal and differentiation into multiple cell lineages.Due to the ease of procurement,robust expansion in vitro,the multipotency,they are recognized as a vital source of stem cells in the field of regenerative medicine.MSCs can be isolated from various tissues,including bone marrow,adipose tissue,and umbilical cord.Research indicates that Human umbilical cord mesenchymal stem cells(hUCMSCs)play an effective role in wound healing and tissue regeneration,and can be utilized for the repair of skin wounds.They are also considered to be the most promising seed cells for skin tissue engineering.This review aims to provide an overview of the biological characteristics of hUCMSCs,the mechanisms in promoting skin wound healing,and their clinical applications.

Mesenchymal stem cells(MSCs)are multipotent stromal cells that possess the capacity for self-renewal and differentiation into multiple cell lineages.Due to the ease of procurement,robust expansion in vitro,the multipotency,they are recognized as a vital source of stem cells in the field of regenerative medicine.MSCs can be isolated from various tissues,including bone marrow,adipose tissue,and umbilical cord.Research indicates that Human umbilical cord mesenchymal stem cells(hUCMSCs)play an effective role in wound healing and tissue regeneration,and can be utilized for the repair of skin wounds.They are also considered to be the most promising seed cells for skin tissue engineering.This review aims to provide an overview of the biological characteristics of hUCMSCs,the mechanisms in promoting skin wound healing,and their clinical applications.

Objective:To evaluate the feasibility and safety of PT Scope (short for intelligent pressure and temperature controlled flexible ureteroscopy)combined with Thulium laser in the intracavitary treatment of upper urinary tract stones.Methods:A retrospective analysis was conducted on the clinical data of 13 patients with upper urinary tract stones who were treated with PT Scope combined with Thulium laser lithotripsy in Sun Yat-Sen Memorial Hospital from February to April 2024. There were 7 males and 6 females. The patients had a mean age of (46±10) years old, with an accumulated stone diameter of (25.8±13.3) mm. There were 7 cases of lower calyx stones (53.8%), and 3 cases of concomitant ureteral stones (23.1%).Four patients (30.8%) had positive preoperative urine cultures, and six patients (46.2%) had leukocyte counts greater than 100 cells/μl in their urine tests. The Thulium laser power was set at 45 W (1.5 J at 30 Hz, 0.3 J at 150 Hz). The renal pelvic pressure threshold was set at 30 mmHg (1 mmHg=0.133 kPa), and the temperature threshold at 43 ℃. Postoperatively, double J stents were placed for 2 to 4 weeks.Results:All 13 patients successfully completed the surgery. The median operative time was 30 (25, 90) minutes. The intraoperative average renal pelvic pressure in these 13 patients ranged from 8 mmHg to 24 mmHg, and the average renal pelvic temperature ranged from 25 ℃ to 34 ℃. Postoperatively, 1 patient experienced a fever (38.0 ℃) and 2 patients required analgesic treatment due to postoperative pain. There were no other intraoperative or postoperative complications. The median postoperative hospital stay was (1.5±0.8) days. The stone-free rate of 1 month was 84.6%(11/13).Conclusions:PT Scope combined with Thulium laser could effectively control renal pelvic pressure and temperature, achieve a high stone-free rate, and have a low complication rate. It is a safe and effective treatment for upper urinary tract stones.

Current status and problems of experimental teaching for medical postgraduate were an-alyzed. Based on experimental teaching in Center of Experimental Teaching for Postgraduates in Medicine at Xi'an Jiaotong University , application of flipped classroom to experimental teaching for postgraduates were discussed in details. Application of flipped classroom to experimental teaching of Cellular and Molec-ular Biology for postgraduates in medicine was introduced. After advantages and disadvantages of flipped classroom were analyzed, countermeasures were proposed. Combining flipped classroom with traditional teaching method is considered to be helpful to the utilization of flipped classroo, and the enhancement of in-novative thinking of postgraduates.

New characteristics and changes of laboratory security were summarized,and then current status and problems of awareness of laboratory security of medical postgraduate under the new situation were analyzed in detail.Based on laboratory security education in Center of Experimental Teaching for Postgraduates in Medicine at Xi'an Jiaotong University,strategies to enhance their awareness and capacity of laboratory security were proposed.Compilation of textbooks on laboratory security,development of curriculum content,training of laboratory security practice,and establishment of evaluation system and laboratory access regulation,will be helpful to maximize safety of postgraduates and to guarantee security of laboratory.

Objective To establish cell lines with inducible replications of wild?type or rtE218G, an adefovir?dipivoxil?resistant HBV mutant. Methods Tetracycline transactivator (tTA) was stably transfected into human liver cell line HepG2.1.2 folds of full?length of wild?type or rtE218G?mutated HBV genomes were cloned into the pTRE vector and co?transfected into the tTA?expressing cells with a linear selection marker for hygromycin, respectively. After hygromycin screening, clones with the highest levels of tetracycline?inducible HBV replications were selected. The obtained cell lines were further used to evaluate the in vitro sensitivity of rtE218G mutant to adefovir?dipivoxil. Results HepG2?off23, a HepG2?derived cell line with stable tTA expression was established. PTRE?based plasmids carrying wild?type HBV (pTRE?HBV?WT) or rtE218G mutant (pTRE?HBV?E218GHBV) were constructed. After stable transfection of the HBV constructs into HepG2?off23 cells, cell lines with robust and tetracycline?inducible replications of wild?type HBV (HepG2?tetHBV?WT) and rtE218G?mutated HBV (HepG2?tetHBV?E218G) were selected. In the two cell lines, high levels of viral core protein and DNA replication could be detected after 144 hours of culture, which could be potently inhibited when tetracycline was added into the medium. At the presence of 1 000 ng/ml of tetracycline, HBV replication intermediates were hardly detected by Southern blotting experiments. HBV mutant with rtE218G could independently confer resistance to adefovir in vitro. IC50 for HBV rtE218G mutant of adefovir was (6.49±0.09)μmol/L, which was significantly higher than that for wild type virus (2.49 ± 0.05)μmol/L. Conclusion Wild?type and the rtE218G HBV mutant could be expressed and efficiently regulated by tetracycline in the established new cell lines. These cell lines could be useful tools for the HBV virology and anti?HBV drug screening studies.

Objective To establish cell lines with inducible replications of wild?type or rtE218G, an adefovir?dipivoxil?resistant HBV mutant. Methods Tetracycline transactivator (tTA) was stably transfected into human liver cell line HepG2.1.2 folds of full?length of wild?type or rtE218G?mutated HBV genomes were cloned into the pTRE vector and co?transfected into the tTA?expressing cells with a linear selection marker for hygromycin, respectively. After hygromycin screening, clones with the highest levels of tetracycline?inducible HBV replications were selected. The obtained cell lines were further used to evaluate the in vitro sensitivity of rtE218G mutant to adefovir?dipivoxil. Results HepG2?off23, a HepG2?derived cell line with stable tTA expression was established. PTRE?based plasmids carrying wild?type HBV (pTRE?HBV?WT) or rtE218G mutant (pTRE?HBV?E218GHBV) were constructed. After stable transfection of the HBV constructs into HepG2?off23 cells, cell lines with robust and tetracycline?inducible replications of wild?type HBV (HepG2?tetHBV?WT) and rtE218G?mutated HBV (HepG2?tetHBV?E218G) were selected. In the two cell lines, high levels of viral core protein and DNA replication could be detected after 144 hours of culture, which could be potently inhibited when tetracycline was added into the medium. At the presence of 1 000 ng/ml of tetracycline, HBV replication intermediates were hardly detected by Southern blotting experiments. HBV mutant with rtE218G could independently confer resistance to adefovir in vitro. IC50 for HBV rtE218G mutant of adefovir was (6.49±0.09)μmol/L, which was significantly higher than that for wild type virus (2.49 ± 0.05)μmol/L. Conclusion Wild?type and the rtE218G HBV mutant could be expressed and efficiently regulated by tetracycline in the established new cell lines. These cell lines could be useful tools for the HBV virology and anti?HBV drug screening studies.

Objective To examine the association between the polymorphisms of brain-derived neurotrophic factor (BDNF)gene with heroin dependence.Methods Genomic DNA was isolated from the venous blood leukocytes of 308 unrelated patients with heroin dependence and 31 7 healthy individuals.Seven single nucleotide polymorphisms (SNPs)were genotyped using MassARRAY system.Data were analyzed using HaploView 4.0 and SPSS 20.0 software.Results There was a significant difference in the genotype frequency of rs6265 between heroin dependence group and healthy control group (χ2 =1 5.1 5 1,P =0.001).The rs6265 G allele was significantly higher than in controls (χ2 =9.864,P =0.002,OR =1.429,95% CI =1.143 -1.786).Furthermore,there was also a significant difference in the genotype frequency of rs13306221 between heroin dependence group and control group (χ2 =7.699,P =0.006).The rs13306221 G allele was significantly higher than in controls (χ2 =7.137,P =0.008,OR =0.539,95% CI =0.340-0.853).Strong linkage disequilibrium (LD)was observed in one block (D’> 0.9;r 2 >0.8),and significantly less G-G haplotype frequency of block 1 (χ2 =4.546;P =0.033)was found in heroin dependence group. Conclusion Our findings support the role of BDNF rs6265 and rs13306221 polymorphisms in heroin dependence and may guide future studies to identify other genetic risk factors for heroin dependence.

Objective To evaluate clinical significance of two real-time fluorescence quantitative PCR kits for quantitative detection of HBV DNA and detection performance at different viral load levels.Methods A series of calibrators with different concentrations(1×106,5×105,1×105,5×104,1×104,5×103,1×103,5×102,1×102,1×101 kIU/L) were prepared with AB-type sera using the second generation WHO international standard (NIBSC code:97/750). HBV viral load in the sera of 78 patients,30 healthy blood donors and 10 calibrators were detected by real-time fluorescence quantitative PCR HBV DNA test kit from PIJI Bio-Technical Development Company Ltd (PG kit) and Cobas AmpliPrep/Cobas TaqMan HBV test kit. The correlation of the two methods was evaluated, and the performance of the two kits different viral load levels was evaluated. The false negative rate was analyzed. Negative control, low positive control and high positive control were included in every batch. Results Both two kits showed the correct results for the 10 specimens from the WHO international standards. The lowest detection limit of HBV DNA for Roche Cobas AmpliPrep/Cobas TaqMan HBV test and PG kit were 2.00 (kIU/L, lg) and 3.00 (kIU/L,lg) ,respectively. There was linear correlation between the results from Roche Cobas AmpliPrep/Cobas TaqMan HBV test and PG kit ( R2=0.938 7, P < 0.01 ), the upper limit of Roche kit had coincided with theoretical value. The samples with HBV DNA level above the upper limit of detection were diluted and retested to obtain the precise result. The result form Roche Cobas AmpliPrep/Cabas TaqMan HBV test [(8.35±0.20) kIU/L, lg] was higher than that from PG kit [(7.73±0.42 ) kIU/L, lg] (t=3. 776, P <0.05) . The detection of 108 serum samples showed that the level of HBV DNA detected by Roche Cobas AmpliPrep/Cobas TaqMan HBV test [(5.88±1.64) kIU/L, lg] was higher than that by PG kit [(5.25±1.55 kIU/L,lg] (t=12. 297 ,P <0.01 ). The correlation coefficients were high in samples with high HBV viral load[HBV DNA(>5.00 and≤7.00) kIU/L,Ig,R2=0. 779 7, P <0.01 ;HBV DNA( >7.00 ands≤9.00) kIU/L,lg,R2=0.603 7, P <0.01]. The correlation coefficient was low in samples with low HBV viral load[HBV DNA ( > 3.00 and≤5.00) kIU/L, lg, R2=0. 417 3, P <0.01 )]. When HBV DNA ( >3.00 and≤4.00) kIU/L,lg,the false negative rate was 33.3% (5/15). When HBV DNA ( > 1.08and≤3.00) kIU/L,lg,none of positive samples was detected with PG kit. Conclusions PG kit is not as good as Cobas AmpliPrep/Cobas TaqMan HBV test . The linear correlation between the results from the two kits is good. The correlation between the results detected with PG kit and Cobas AmpliPrep/Cobas TaqMan HBV test is higher in the high viral load groups than in the low viral load group. It is suggested that PG kit had a narrower linear range.

Objective To determine the distribution of HCV genotypes in patients with chronic hepatitis C,study the distribution of genotype in different gender and the relationship between genotypes and serum HCV-RNA levels.Methods Two hundred and six cases of HCV RNA positive patients(all with relevant clinical data) receiving pegylated interferon therapy were collected from May to December 2010.HCV RNA was detected in 206 hepatitis C patients from 40 hospitals in China by Roche Cobas AmpliPrep/Cobas TaqMan HBV test,and genotype was determined by Abbott RealTime HCV G enotype Ⅱ .The distribution of genotypes in the gender was analyzed by chi-square test analysis.The relationship between genotypes and serum HCV RNA levels was detected by single factor analysis and two independent sample t test analysis.Results There were seven different subtypes of HCV in 206 samples,including genotype 1,7 cases(3.4% ,7/206); genotype 1a,2 cases(1.0%,2/206); genotype 1b,123 cases (59.7 %,123/206); genotype 2,32 cases(15.5 %,32/206); genotype 3,27 cases(13.1%,27/206); genotype 6,6 cases(2.9% ,6/206) ;genotype 1/6,5 cases(2.4% ,5/206) ;genotype 2/4,1 cases(0.5%,1/206).There was no significant difference between HCV genotype and gender in 132 cases with genotype 1 and 65 cases with non-genotype 1(genotype 2,3,6) (x2 = 0.000,P ＞ 0.05).There was significant association between quantity of HCV RNA and genotype in 188 patients with HCV(F = 3.371,P＜ 0.01).The 197 patients with HCV single genotype were divided into five groups in terms of region(East,South,West,North and Center).There was no significant difference between HCV genotype 1 and non-genotype 1 in the five groups(x2 = 5.840,P ＞ 0.05).Conclusions It is suggested that HCV 1 b is the most prevalent type in China,followed by HCV 2.There is no significant difference between HCV genotype and gender.The levels of HCV RNA with genotype 1b are significantly higher than those with genotype 3.The levels of HCV RNA with genotype 2 are significantly higher than those with genotype 3.The levels of HCV RNA with genotype 6 are significantly higher than those with genotype 3.