RNA interference(RNAi), a highly conserved process of post-transcriptional gene silencing, can be induced by small interfering double-stranded RNA that mediate sequence-specific mRNA degradation. In the past several years, RNAi has been widely used as both an experimental tool to study mammalian gene function and a potential therapeutic approach to treat human diseases. In addition, some new proteins which involve in RNAi pathway have been characterized in mammalian cells. Here, we summarize the various molecules in RNAi, mechanism of action, and the current therapeutic applications in cancers.

Objective To explore the effect of glycine on the intestinal barrier of rats with obstructive jaundice.Methods The male Wistar rats weighing 220—260g were randomly assigned to three groups(n=20): sham operation group(A),common bile ligation gruop(B),common bile duct ligation plus glycine group(C).Except sham operation group(A),rat models with obstructive jaundice in the other groups were set up by double ligation of the common bile duct.The rats in group C was fed with 5% glycine solution for 5 d.From the second day after the operation,the rats in group C were fed according to the preoperative standard.On the 21th day after operation,the rats were killed and serum bilirubin(BIL) and the amount of nitric oxide(NO) in intestinal tissue were determined,the morphological changes of the intestine were observed,the villus height and mucosal thickness were measured.Results Compared with group A,the serum BIL and the amount of NO in intestinal tissue were increased and the villus height and mucosal thickness were reduced in group B(P0.05) compared with group A.Conclusion Glycine can decrease the level of NO in the intestinal tissue and improve the damaged intestinal barrier obviously.

The modern preventive medicine education system should be reformed,the author proposed the preventive medicine education should establish multi-disciplinary and multi-level training way: depending on the high-quality curriculum of preventive medicine,constructing the platform of the preventive medicine education;setting up the new idea of preventive medicine education,taking the educational model innovation;breaking up the traditional thought pattern,displaying creative thought;developing the exploration of the non-preventive medicine specialized preventive medicine educational pattern.

Objective To investigate the concentration of homocysteine (Hcy) and related factors of hyperhomocyste-inemia (hHcy,Hcy≥15μmol/L) among non-hypertensive people aged between 40-70 in Tianjin. Methods Non-hyperten-sive community residents aged 40-70 years were enrolled randomly from May 2011 to December 2012 in six districts in Tian-jin. Plasma Hcy was assessed by enzyme cycling method. Factors related to hHcy were analyzed in multivariate logistic re-gression models. Results Our study included 874 participants (mean age is 57 ± 6 years, 25.5%of all are males) and the con-centration of Hcy was 12.0 μmol/L. The OR (odds ratio)(95%CI; P)for hHcy were 1.048(1.015,1.083; P=0.004), 4.191 (2.359,7.448;P<0.001), 1.280(0.896,1.829;P=0.175), 0.460(0.259,0.816;P=0.008)respectively for age, male, smoking, exercise, and the odd ratio for hHcy were 0.290(0.179, 0.469;P<0.001), 0.168(0.092,0.309;P<0.001)for consumption of vegetable and fruits 250-500 g/d and>500g/d, compared with<250 g/d. Conclusion Male and age were adverse factors for hHcy, consumption of vegetable and fruits, and exercise were positive factors.

Purpose To identify whether serum-free culture can enrich breast cancer stem cells from MCF-7 human breast cancer cell line. Methods MCF-7 human breast cancer cell line by serum-free culture and serum culture technology were cultured, its cell mor-phology and growth pattern were observed by the inverted microscope. The expression of stem cell surface molecular makers CD24, CD44 was observed by the inverted fluorescence microscope and the flow cytometry, the proportion of different subpopulation cells was detected by the flow cytometry. At the same time, difference of the cell cycle was detected by the flow cytometry. Results The cell line cultured by serum-free culture grew in the form of suspended microspheres of different sizes in the medium, but the cell line cul-tured by serum culture grew in the form of monolayer adherent growth. There was no obvious difference in the expression of stem cell surface molecular makers CD44 between the suspended microsphere cells and the adherent cells, but the expression of CD24 in the sus-pended microsphere cells decreased compared to the adherent cells. The proportion of CD44 + /CD24 -/low phenotype cells in the suspen-ded microsphere cells and the adherent cells was (86. 93 ± 0. 53)% and (19. 98 ± 0. 62)%, respectively (P<0. 05), the proportion of CD44 + /CD24 + phenotype cells was (12. 68 ± 0. 59)% and (79. 90 ± 0. 57)%, respectively (P<0. 05). The proportion of mitotic cells in the suspended microsphere cells and the adherent cells was ( 18. 85 ± 2. 26 )% and ( 43. 91 ± 1. 81 )%, respectively ( P<0. 05), the proportion of quiescent cells was (64. 92 ± 2. 07)% and (39. 82 ± 1. 77)%, respectively (P<0. 05). Conclusion CD44 + /CD24 -/low breast cancer stem cells can be effectively enriched by the serum-free culture technology.

This text briefly introduces tutorial system's history evolution and development and expounds its necessity and realistic meaning,emphasizing that practising such a guidance program is necessary for developing students' innovative ability and individuality,and for strengthening the construction of the teachign staff,which is the call of students and the responsibility of education,and the inevitable choice under credit system.It focuses on how to set up effective and practical tutorial system of the undergraduate course from the construction of tutors'troops,the feasible measures and system,and tutor stimulative mechanism.

Objective To explore whether low-dose occupational ionizing radiation exposure can affect the prevalence of lens opacity.Methods Annual occupational health checkup data of 1 007 radiation workers was taken from a provincial medical institution for the purpose of statistical analysis.Logistic regression analysis was used to estimate occupational exposure odds ratios (OR) of lens opacity,adjusted for age,gender and length of service.Eye lens opacity was grouped into cortical,nuclear and posterior subcapsular opacity according to the position of the opacity occurrence site.Opacity occurred in any one of the both eye lens was recorded as turbidity.Results Only 730 cases coupled with complete information could be used in the statistical analysis.The rate of lens opacity for all the radiation workers was 10.27％.The rates of lens opacity by exposure group were estimated to be 9.07％ for radiation diagnosis and therapy group,11.11％ for intervention group,18.18％ for nuclear medicine group,and 9.33％ for industrial application group,respectively.Compared with those in the radiation diagnosis and therapy group,the workers engaged in intervention medicine,or nuclear medicine,were more likely to suffer from the lens opacity in posterior subcapsular position.The OR and its 95％ confidence intervals were 3.00 (1.23-7.33),4.12 (1.68-10.11) for the workers in intervention medicine or nuclear medicine group.Conclusions Medical radiation workers,who were exposed to long-term low-dose of ionizing radiation,especially those who engaged in intervention or nuclear medicine,were at significantly higher risk to develop lens opacity.

A technique of diffusive gradients in thin films (DGT) was developed for the in situ measurement of reactive phosphorus species in natural waters, sediments and potentially soils. Polyacrylamide / basic magnesium carbonate was used as the novel binding phase of DGT. Various factors, such as initial concentration, deployment time, pH and ionic strength, which may affect the adsorption of phosphate to the DGT were investigated. H2 SO4(0. 25 mol/ L, 10 mL) was used for elution of phosphate from the binding gel, and an elution efficiency of 85±5% was obtained. The DGT measurement was independent of ionic strength (0. 001-0. 05 mol/ L) and pH (4. 10-9. 15). The results indicated that the maximum adsorption capacities of DGT were limited to 20. 4 μg per disc ( T = 25℃, pH = 7. 00, [ P] = 2 mg / L). Good agreement was obtained between the measurement results of DGT method and molybdenum blue method in the P concentration from 0. 001 to 20 mg / L. The method detection limit (MDL) was 102. 4 ng / L. Field performances of DGT in synthetic seawater, the coastal seawater of Xiamen, Lake Yihai, Lake Chaohu and Nanfei River indicated that the basic magnesium carbonate-DGT method was more reliable than the commonly used ferrihydrite-DGT method.

OBJECTIVE To investigate the effect of clopidogrel(Clog),a platelet aggregation inhibitor,on the development of colitis-associated colon cancer(CAC)and its possible mechanism. METHODS To establish a CAC model,male BALB/c mice were treated with single azoxymethane(AOM) 10 mg · kg-1 by ip. One week later,the mice drank 2.5% dextran sulfate sodium(DSS)for one week and water for two weeks,which lasted three cycles. From the first day mice received 2.5%DSS water, Clog 12.5,25.0 and 50.0 mg · kg-1 was ig administered once a day. Body mass,clinical symptoms,the number of colon tumor and tumor size in colon tissue were recorded. Hyperplasia of tumors was analyzed by HE staining. In the early inflammatory phase of the CAC model,the length of colons was measured, histological structure and epithelium cell proliferation of colon tissues were evaluated by HE staining and Ki67 staining,respectively. In the tumorigenesis and progression phase of the CAC model,epithe?lium cell proliferation of colon tissues was evaluated by Ki67 staining. The mRNA expression of tumor necrosis factor-α(TNF-α)was detected by real-time quantitative PCR. The expression of chemokine(C-X-C motif)ligand 2(CXCL2)and its receptor 2(CXCR2)in colon tissues was detected by PCR and immu?nohistochemistry. RESULTS Compared with model group,clinical symptoms of mice in Clog 12.5 mg · kg-1 group were alleviated,the size of colon tumors was decreased(P<0.05),and hyperplasia of tumors was reduced(P<0.05). During the inflammatory phase,the clinical symptoms of mice in Clog 12.5 mg·kg-1 group were significantly alleviated(P<0.05),the decrease of body mass was reduced(P<0.01),the colon shrinkage was ameliorated(P<0.01),the inflammatory injury and epithelium cell proliferation in colon tissues were reduced(P<0.05). During the tumorigenesis and progression phase,epithelium cell prolif?eration in colon tissues in Clog 12.5 mg·kg-1 group was reduced(P<0.01),and the mRNA and protein expression of TNF-α,CXCL2 and CXCR2 of colon tissues was decreased(P<0.05). CONCLUSION Clog can alleviate inflammation during the CAC early inflammatory phase and inhibit the formation of CAC. The antitumor effect of Clog may be related to the decrease in expression of CXCL2 and CXCR2.

Hepatic venous pressure gradient (HVPG) is the gold standard for the degree of cirrhotic portal hypertension and has limited use in clinical application, and therefore, there is an urgent need for noninvasive assessment methods for portal hypertension. This article introduces various serological, imaging, and elastography methods and combined diagnostic models and elaborates on the current research results and the advantages and disadvantages of each method. It is pointed out that in future, noninvasive diagnostic techniques may play a greater role in screening, monitoring, and risk stratification of patients with cirrhotic portal hypertension.