Background and purpose: Pancreatic intraepithelial neoplasia (PanIN) is thought to be a precursor lesion of infiltrating pancreatic ductal adenocarcinoma. The mutation of the phenotypic impact of K-ras G12D alone, silencing of p53 and p16 could promote this process. The role of Smad4 in this progression was poorly understood. In the present study, we investigated the role of Smad4 in the development of pancreatic tumor, based on PanIN cell line from mice with K-ras G12D mutation in order to investigate the effect of Smad4 silencing on PanIN cells in the development and malignant transformation in nude mice. Methods: Smad4 knock-down PanIN cells (PanIN-S) were established by stable transfeetion with lentiviral-mediated Smad4 RNA interference (RNAi). In xenograft model experiments, BALB/c nude mice were randomly divided into 2 groups (5 mice per group) implanted with PanIN or PanlN-S cells subcutaneously. Two weeks after tumor cells inoculation, tumor volume and weight were estimated. PCNA staining was used to evaluate cell proliferation and CD31 polyclonal antibody was used to assess micro-vessel density (MVD) in tumors. Results: Effect of siRNA of Smad4 gene in PanlN cells was confirmed by RT-PCR and Western blot. Compared with PanlN groups, there was a dramatic increase in tumor volume and weight in PanIN-S groups (P<0.05). Furthermore, immunohistochemical analysis of the harvested tumors suggested that Smad4 silencing was associated with 'increased tumor cell proliferation (PCNA reactivity) and angiogenesis (micro-vessel density, MVD). The percentage of PCNA-positive cells in the PanlN-S groups were significantly increased than PanIN groups (P<0.05). CD31 staining revealed a significant increase in the PanlN-S groups compared to the PanlN groups (P<0.05). Conclusion: Silencing of Smad4 in PanlN cells with endogenous expression of K-ras G12D, enhanced progression to invasive adenocarcinomas. Cell proliferation and vascularization may be its important mechanisms.

Suffering is prevalent in the palliative care population and is an important factor affecting the quality of life of palliative care patients and their family caregivers. In this paper, we review the assessment content, measurement methods, current application status and advantages and disadvantages of suffering assessment tools for palliative care patients, analyze the problems of current suffering assessment tools for palliative care patients and make suggestions, aiming to provide reference for palliative suffering treatment in China.

OBJECTIVE: To investigate the prevalence and influencing factors of work-related musculoskeletal disorders(WMSDs) among workers in a cement plant. METHODS: A total of 196 workers in a cement plant were selected as study subjects using a judgment sampling method. A revised Musculoskeletal Injury Questionnaire was used to investigate the occurrence of WMSDs in workers in the past year. RESULTS: The detection rate of WMSDs in different parts of the body of workers in the cement plant was 18.4%-32.1%. The detection rates of WMSDs in all parts of the body from high to low was as follows: shoulder(32.1%), neck(30.6%), upper back(24.0%), ankle/foot(24.0%), lower back(23.5%), hip/thigh(22.4%), wrist/hand(21.4%), elbow(18.4%), and knee(18.4%). Multivariate logistic regression analysis results showed that keeping the neck in the same posture for a long time was a risk factor for neck WMSDs [odds ratio(OR)=2.29, P<0.05). Frequent turning around was a risk factor for WMSDs on the neck and lower back(waist)(OR were 3.06 and 3.32, P<0.05). Maintaining the same posture for a long time on the back was a risk factor for shoulder and upper back WMSDs(OR were 3.22 and 2.34, P<0.05). Hard work was a risk factor for shoulder and upper back WMSDs(OR were 2.60 and 2.58, P<0.05). Driving a vehicle was a risk factor for lower back(waist) and ankle/foot WMSDs(OR were 2.54 and 3.17, P<0.05). Carrying objects heavier than 20 kilograms and frequent overtime working were risk factors for ankle/foot WMSDs(OR were 3.03 and 2.54, P<0.05). CONCLUSION: The most frequent parts of the body having WMSDs in the cement production workers are shoulders and necks. Occupational factors(turning around or keeping the same posture of neck and back) are risk factors of WMSDs on shoulder and neck.