During the recent 5 years,an upsurge of stem cell biology research has appeared around the world with a huge number of papers published.A part of them,however,concluded with a hypothesis of so called "transdifferentiation" or "stem cell plasticity" that stem cells could transform into any other tissues such as fats becoming liver or muscle changing into nervous cells and so on,that all lacks of strong evidence.The discovery of adult stem cells(ASC) in the adult tissues was actually a great scientific epoch-making towards the end of 1999 though the authors made a wrong conclusion of transdifferentiation at that time.More and more evidences showed that the ASC in the adult tissue are the remnants of stem cells from every stage of embryonic development.The tissue specific stem cells harbored in the adult tissues can only be induced to differentiate in the progeny cells of its own committed origin.ASC includes hematopoietic and non-hematopoietic stem cells and there are lots of stem cells in the latter,like nervous stem cells and mesenchymal stem cells(MSC).The progenies of MSC are the connective tissues,such as osteoblasts,chodroblasts,myocytes,angio-endothelio cells,etc,which are most important during the recovery and reconstitution of tissue injury,ischemic necrosis and hematopoietic damage.

In order to examine the feasibility of cytokine fusion gene transfer into tumor cells, a retroviral vector (pLXSN) for human interleukin 6/interleukin 2 (IL6/IL2) fusion gene was constructed by using PCR and ligating the 2 genes with a synthesized flexible linker. The IL6/IL2 fused gene was introduced into B16 melanoma cell line mediated by retrovirus and the changes of adhesive and metastatic ability of fused gene-modified cells were detected. The B16-IL6/ IL2 cells showed efficient expression of both cytokines and decreased binding affinity with extracellular matrix (Laminin and Matrigel), accompanying with decreased experimental metastatic potentials. These data suggest that the mechanism involving the decreased metastases may relate with the changes of biological characteristics and immune stimulating activity of gene-modified cells.

The clozapine treatment of schizophrenic patients (n=26) for 6 weeks showed the significantly (all P

Many gene therapy protocols can induce antitumor immunity, however, the ex vivo approach restricts their uses. This sutydy intended to induce antitumor immunity by direct transfer of MHC class Ⅱ gene in vivo. Methods: MHC class Ⅱ gene cDNA was introduced directly into two tumors: P815, (a murine weak immunogenic mas-tocytoma) and B16 (a murine nonirnmunogenic melanoma) to observe the survival rate of the mice. Results: Tumori-genicity of P815 was reduced when MHC class Ⅱ gene was introduced directly into tumors in vivo. Further more, most vaccinated mice could survive after second challenge of P815. Co-injection of MHC class Ⅱ and B7 genes in the B16 also resulted in the tumor grow slowly, while the injection of MHC class Ⅱ gene was not enough to induce effective antitumor responses. Conclusion: The results showed the potential applications of direct transfer of MHC class Ⅱ gene in the treatment of tumor.

Objective: A solvent desorption-gas chromatography method for determination of ethylal in workplace air has been established. Methods: Ethylal in workplace air was collected by activated carbon tube and desorbed with carbon disulfide, and the desorption solutions were analysed by capillary column GC with FID detector. Results: The method presented a good linearity in the range of 0.87~34 800.00 mg/L of ethylal in the standard solution, with the correlation coefficient being r=0.999 7. The limit of detection and the limit of quantification of this method were respectively 0.20 mg/L and 0.80 mg/L, and the minimum detectable concentration and the minimum quantification concentration of this method were respectively 0.17 mg/m³ and 0.60 mg/m³ per 1.50 L of air.The within-run precision of the method was 2.93%-6.20%, and the between-run precision 3.67%-6.44%. The desorption efficiency between 94.22%-97.27%. Ethylal in activated carbon tube could be kept at least 7 days at room temperature without significant loss. Conclusion The method could be used for determination of ethylal in workplace air.

OBJECTIVE: To explore the applicability of Singapore Ministry of Manpower( MOM) risk model and MES model in risk assessment of occupational health hazard caused by chemical poisons in shoemaking enterprises. METHODS: A medium-sized shoemaking enterprise in Guangzhou City was selected as the research object to carry out on-the-spot investigation of occupational health,measure the level of chemical hazards in the air of the workplace. Occupational health risk assessment of chemical toxins in the workplace was conducted using the MOM model and the MES model,and the results of the two evaluations were compared. RESULTS: The occupational chemical hazards in workplace of the shoemaking enterprise mainly included the toluene,xylene,ethyl acetate,butyl acetate,n-hexane,and 1,2-dichloroethan( 1,2-DCE). The concentration-time weighted average( CTWA) of 1,2-DCE at the stitching post,methylbenzene at the brush coating post and ethyl acetate at the cleaning post exceeded occupational exposure limits. The MOM model assessment results showed that methylbenzene was of high risk and 1,2-DCE was of medium risk in brush coating post. n-Hexane and1,2-DCE were of medium risk in stitching post. Ethyl acetate and 1,2-DCE was of medium risk in cleaning post. The results of the MES model evaluation showed that the risk level of n-hexane and 1,2-DCE used in sticking,brush coating and cleaning posts was extremely high and the remaining chemicals were highly dangerous. CONCLUSION: Both MOM model and MES model can easily predict and assess the occupational health risk of various posts in shoemaking enterprises to some extent. The assessment result of MES model is more practical than that of MOM model.

Purpose: This study aims to comprehensively evaluate the clinical efficacy of chemotherapy or endocrine therapy maintenance in metastatic breast cancer (MBC) patients. Materials and Methods: The meta-analysis of randomized clinical trials (RCTs) and propensity score matching of multicenter cohort study evaluated MBC patients who underwent first-line chemotherapy or endocrine therapy maintenance. This study is registered with PROSPERO: CRD42017071858 and ClinicalTrials.gov: NCT04258163. Results: A total of 2,867 patients from 15 RCTs and 760 patients from multicenter cohort were included. The results from meta-analysis showed that chemotherapy maintenance improved progression-free survival (PFS) (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.54 to 0.73; p < 0.001; moderate-quality evidence) and overall survival (OS) (HR, 0.87; 95% CI 0.78 to 0.97; p=0.016; high-quality evidence) than observation. In the cohort study, for hormone receptor–positive MBC patients, chemotherapy maintenance improved PFS (HR, 0.67; 95% CI, 0.52 to 0.85; p < 0.001) and OS (HR, 0.55; 95% CI 0.42 to 0.73; p < 0.001) compared with observation, and endocrine therapy maintenance also improved PFS (HR, 0.65; 95% CI, 0.53 to 0.80; p < 0.001) and OS (HR, 0.55; 95% CI, 0.44 to 0.69; p < 0.001). There were no differences between chemotherapy and endocrine therapy maintenance in PFS and OS (all p > 0.05). Regardless of the continuum or switch maintenance therapy, showed prolonged survival in MBC patients who were response to first-line treatment. Conclusion This study provided evidences for survival benefits of chemotherapy and endocrine therapy maintenance in MBC patients, and there was no difference efficacy between chemotherapy and endocrine therapy maintenance for hormone receptor–positive patients.

Objective: To explore the applicability of Singapore semi-quantitative assessment method and international committee on mining and metals occupational health risk assessment method in occupational health risk assessment of ceramic enterprises. Methods: From March 2017 to May 2018, A ceramic enterprise was selected for the investigation and testing of occupational health, and the risk assessment of the occupational-disease-inductive factors in the workplace was conducted by the semi-quantitative assessment method of Singapore and the occupational health risk assessment method of the international committee on mining and metals. Results: The occupational-disease-inductive factors in the production process of this ceramic enterprise mainly include silicon dust, noise, high temperature, carbon monoxide, carbon dioxide and so on. The two risk assessment methods were applied to assess the risk of occupational-disease-inductive factors in the workplace, and the results showed that the high risk level was 16.67%, the medium risk level was 63.33%, and the low risk level was 20.00%. The risk level of silicon dust is from low risk to high risk. Conclusion The semi-quantitative assessment method and the occupational health risk assessment method of the International Commission on Mining and Metals are simple to operate and practical, and are suitable for the assessment of occupational hazards in ceramic enterprises.