Objective To investigate hepatitis B virus mutation rate after the universal immunization in China. Methods DNA sequence analysis of the “a” determinant was performed on sera from 72 viral carrier children after immunoprophylaxis selected through a sampling survery. Results Four mutants were detected, the mutation rate was 5.56%. One strain showed Gly-to-Arg mutation at the 145 codon of surface antigen. Animo acid substitutions at the amino acid 126 and 140 were noted in the other three children. The epidemiological HBV serotype shifted from previous adw infection to more recent adr was also observed. Conclusions These observations indicate that vaccination is probably the cause of mutation, whereas the mutation is low and it will certainly not be a reason for doubting that the vaccination is the method of main choice for preventing hepatitis B infection that still devastates the developing countries.

Objective:To optimize the macroporous resin separation process for total flavonoids in papaya. Methods:The content of total flavonoids in papaya was selected as the index, and the resin model, sample solution concentration, ratio of diameter and height, the flow rate of adsorption, type and volume of eluent, type and volume of impurity removing solvent, elution velocity and the other parameters were investigated. Results:The optimal purification process was as follows: the macroporous resin type was D-140, the sample solution concentration was 0. 1 g·ml-1 , the sample volume was 2BV, the ratio of diameter and height was 1∶9, washing the impurities with 3BV water, eluting with 3BV 10% ethanol first followed by 3BV 50% ethanol with 2BV·h-1 , and collecting 50%ethanol elution. The total flavonoids content was 52%. Conclusion:The optimized process can separate and purify the total flavonoids in papaya effectively.

BACKGROUND:It has been recently indicated that nervous factors are able to adjust and dominate bone fracture healing. Type Ⅰ collagen is a major factor to promote the differentiation of osteoblasts and enhance the adhesion of osteoblasts; while, it is also a matrix protein for composing bone framework. Type Ⅱ collagen is derived from chondrocytes. OBJECTIVE: To study changing law of type Ⅰ and Ⅱ collagen expression during denervated bone fracture healing. DESIGN, TIME AND SETTING: Randomized controlled anima study was performed at the Animal Laboratory and Cell Biology Laboratory, the Second Military Medical University of Chinese PLA between May and December 2005. MATERIALS: Forty 3-month-year healthy male SD rats were randomly divided into fracture group (tibial fracture alone) and combination group (spinal cord injury combined with tibial fracture), with 20 rats at each group. METHODS: A φ 0.8 mm Kirschner wire was inserted into anterior border of left tibial plateau to establish tibial fracture models in the fracture group. A 0.3-cm spinal cord transection was cut at T10 segment to establish tibial fracture models with entire spinal cord injury. MAIN OUTCOME MEASRUES: Type Ⅰ and Ⅱ collagen protein expressions of callus were detected using Western blot technique in week 1, 2, 4, and 5 post-injury. RESULTS: One week after injury, type Ⅰ and Ⅱ collagen was represented in callus in the two groups, while the expressions in the combination group were significantly higher than fracture group (P<0.05); two weeks after injury, type Ⅱ collagen expression reached at the peak in the combination group, and the expression was significantly higher than the fracture group (P<0.05); four weeks after injury, type Ⅰ collagen expression reached at the peak in the fracture group, and the expression was significantly higher than the combination group (P<0.05), while type Ⅱ collagen still highly expressed in the combination group; five weeks after injury, type Ⅰ and Ⅱ collagen expressions were decreased in the two groups. CONCLUSION: Secretory law of type Ⅰ and Ⅱ collagen during denervated bone fracture healing is similar to normal bone fracture healing; however, the differences at time points, in particular expression at peak, are remarkable between them.

Objective:To explore the association of physical activities,sedentary behaviors with over-weight/obesity in Chinese children aged 9 -1 1 years,analyze the gender difference and heterogeneity of the association across different provinces,and provide evidence for prevention and control of overweight and obesity.Methods:Using the data of 40 692 children aged 9 -1 1 years from Chinese National Survey on Students’Constitution and Health in 201 0,the height and weight were measured and the time spent in physical activities,screen behaviors and homework were collected.We analyzed the associations among physical activities,sedentary behaviors and overweight/obesity in boys and girls separately,and assessed the heterogeneity of associations across different provinces with Meta-analysis.Results:The prevalence of overweight/obesity of the boys (27.1 %)was higher than that of the girls (1 2.9%),compared with the rural students (1 5.6%),the situation of overweight/obesity of the urban students (23.8%)was more serious,the prevalences of overweight/obesity were separately 22.6%,1 9.2% and 1 7.5% among developed,middle-developed and undeveloped social economic status subgroups.The boys with physical activities no more than 1 hour per day were more likely to be overweight/obese,with the OR of 1 .09 (95%CI:1 .02,1 .1 7).The girls with screen time more than 1 hour per day or homework time more than 2 hours per day were more likely to be overweight/obese,with the ORs of 1 .1 3 (95%CI:1 .02, 1 .26)and 1 .1 8 (95%CI:1 .03,1 .35)respectively.The high level of sedentary behaviors (more than 1 35min per day)was associated with overweight/obese in the girls,and the OR was 1 .1 9 (95%CI:1 .08,1 .33).There was no significant heterogeneity of effect values between physical activities and over-weight/obesity in the boys and between sedentary behaviors and overweight/obesity in the girls across the different provinces (P >0.05).Conclusion:The associations among physical activities,sedentary be-haviors and overweight/obesity existed in Chinese children aged 9 -1 1 years,which were different in boys and girls.There was no statistically significant heterogeneity across different provinces.The strate-gies to prevent and control overweight/obesity in primary school students should focus on gender-specific needs.

In educating postgraduate students in aerospace medicine in our country, there are some deficiencies such as the course content lacking forward looking and systematicness, and students' mastery of technology or skills lacking professional characteristics, innovation and divergent thinking. Based on the original foundations, the School of Aerospace Medicine, Fourth Military Medical University, has been con-structing and improving the course system by modifying the course contents, reforming the practical teach-ings, expanding the academic communications, and managing the processes. Finally, they have achieved certain results.

Objective:To establish an HPLC method for the simultaneous determination of liquiritin and glycyrrhizic acid in Erxieting granule.Methods:A TechMate C18-ST(250 mm×4.6 mm,5 μm) column with a DAD detector was used.The mobile phase consisted of acetonitrile (A) and 0.05% phosphoric acids in water (B) with gradient elution.The flow rate was 1.0 ml·min-1 and the detection wavelength was 237 nm.The sample size was 5 μl and the column temperation was room temperatence.Results:Linear calibration curves were obtained within the range of 10.32-51.62 mg·L-1 for liquiritin and 79.40-397.00 mg·L-1for glycyrrhizic acid.The average spiked recovery of liquiritin and glycyrrhizic acid was 98.10(RSD=1.0%,n=6)and 97.15(RSD=1.8%,n=6),respectively.Conclusion:The method is accurate,reproducible and stable,and can be used for the quality control of Erxieting granule.

Chromosomal integration enables stable phenotype and therefore has become an important strategy for breeding of industrial Saccharomyces cerevisiae strains. pAUR135 is a plasmid that enables recycling use of antibiotic selection marker, and once attached with designated homologous sequences, integration vector for stable expression can be constructed. Development of S. cerevisiae strains by metabolic engineering normally demands overexpression of multiple genes, and employing pAUR135 plasmid, it is possible to construct S. cerevisiae strains by combinational integration of multiple genes in multiple sites, which results in different ratios of expressions of these genes. Xylose utilization pathway was taken as an example, with three pAUR135-based plasmids carrying three xylose assimilation genes constructed in this study. The three genes were sequentially integrated on the chromosome of S. cerevisiae by combinational integration. Xylose utilization rate was improved 24.4%-35.5% in the combinational integration strain comparing with that of the control strain with all the three genes integrated in one location. Strain improvement achieved by combinational integration is a novel method to manipulate multiple genes for genetic engineering of S. cerevisiae, and the recombinant strains are free of foreign sequences and selection markers. In addition, stable phenotype can be maintained, which is important for breeding of industrial strains. Therefore, combinational integration employing pAUR135 is a novel method for metabolic engineering of industrial S. cerevisiae strains.
Genetic Engineering ; methods ; Genetic Vectors ; Metabolic Engineering ; Plasmids ; genetics ; Saccharomyces cerevisiae ; genetics ; Xylose ; metabolism

BACKGROUND:To in vitro isolate neural stem cel s with high purity and uniform biological properties and to establish a complete set of neural stem cel culture system is the basis for neural stem cel research.
OBJECTIVE:To establish an isolation and culture system for neural stem cel s from newborn mouse hippocampus, olfactory bulb and cortex and to analyze the biological properties of cel s.
METHODS:Neural stem cel s were isolated from the hippocampus, olfactory bulb and cortex tissue of newborn Kunming mice by mechanical separation and trypsin digestion. Serum-free culture technology, mechanical pipetting and trypsin digestion were used for subculture of neural stem cel s. 10%fetal bovine serum was used to induce differentiation of neural stem cel s. Neural stem cel s and their differentiated products were identified by
immunofluorescent staining of Nestin, CD133,β-TubulinIII, glial fibril ary acidic protein.
RESULTS AND CONCLUSION:The neural stem cel obtained from newborn mouse hippocampus, olfactory bulb and cortex had the capacity of self-renewal and differentiation which were positive for Nestin and CD133. After induction with fetal bovine serum, neural stem cel could differentiation toβ-tubulinIII or glial fibril ary acidic protein positive cel s that were neurons and astrocytes. This experiment has successful y established the neural stem cel isolation, culture, identification and induction system, providing experimental basis for subsequent studies of neural stem cel s.

Objective:To study the relationship between rs 2228314 polymorphism in sterol regulatory element binding protein 2 gene (SREBP2) and obesity, serum lipid levels in children and adolescents . Methods:In our study , 2 030 children and adolescents aged from 7 to 18 years participated .Anthropo-metric measurements, including height and weight, were performed.Their serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol ( HDL-C) were detected .The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS ) was used to detect rs2228314 genotypes.Results: The GC/CC genotypes of rs2228314 polymorphisms had lower HDL-C levels than GG genotype [(0.10 ±0.35) mmol/L vs. (0.14 ±0.36) mmol/L, P=0.020].The rs2228314 polymorphism was associated with the abnormal HDL-C level under the dominant model after adjustment for study samples , sex and age ( OR=1.400, 95%CI:1.027-1.907, P=0.033).The rs2228314 polymorphism was not associated with obesity un-der the dominant model after adjustment for study samples , sex, age and HDL-C level ( OR=1.178, 95%CI: 0 .971 -1 .430 , P =0 .096 ) . Conclusion: The GC/CC genotype carriers of SREBP2 rs2228314 polymorphism have higher risk of abnormal HDL-C level than the individuals with GG geno-type among children and adolescents .

According to the recommended diagnostic criteria of obese adults in Asia-Pacific region,8 284 cases of middle-aged and elderly people in Uygur and Han populations were collected randomly to study the status and distribution characteristics of two nationalities.Standardized prevalences of obesity were 20.1 2%in Uygurs and 23.077%in Hans.Woman in Hans reached the highest prevalence.Alcohol-drinking,abnormal giycometabolism,and serum cholesterol levels were the most relevant risk factors.