AIM: To evaluate the relationship between the medial rectus cells counts in concomitant exotropia and surgical results. METHODS: A total of 32 pieces of medial rectus muscle were collected for HE staining in this study, of which 18 pieces were from patients with concomitant exotropia and 14 pieces were from healthy individuals. A method of strabismus score was used to assess the operative effect.RESULTS: The difference of strabismus score before and after the operation in the intermittent exotropia group was significantly higher than that in constant exotropic group (P<0.01). Under light microscope, the loosen muscle fibers and the increased stromal components in the cross sectional area of medial rectus were observed in strabismic group. The muscle cells counts was obviously lower in strabismic group than in control group (P<0.01), which was related to the difference of strabismus score before and after the operation (P<0.05).CONCLUSION: The decreased medial rectus cells counts induce concomitant exotropia directly. It is the crucial causes of the bad surgical results.

Objective To investigate the prevalence of osteoarthritis in inhabitants aged 40 years old and above from urban and rural areas in Heilongjiang province. Methods Through multistage stratified cluster random sampling methods, residents aged 40 years and above were selected. All subjects were given a standardized questionnaire and were conducted a radiographic examination on hands, knees, neck spine and lumbar spine after informed consent. All statistics were performed by SPSS13.0. Results A total of 1196 residents were surveyed, which including 573 males and 623 female subjects. The prevalence of osteoarthritis in cervical spine, lumbar spine, knee and hand for men were 26.00%, 31.20%, 11.87%, 15.53%, respectively and that were 34.80%, 30.20%, 20.06%, 27.93% for women respectively. The prevalence of osteoarthritis increased with aging both in men and women. Prevalence in 60-70 age group achieved the peak. The prevalence rates became relatively low among those over the 70 years old than expected. The most common sites of osteoarthritis were knees and hands (16.10%), followed by cervical and lumbar spine (12.40%).Conclusion The prevalence of osteoarthritis was generally high in middle and old-aged people in Heilongjiang province.

OBJECTIVETo investigate the effects of miR-21 on paclitaxel-resistance in human breast cancer MCF-7/PR and SKBR-3/PR cells.

METHODSPaclitaxel-resistant human breast cancer cell lines MCF-7/PR and SKBR-3/PR were established by stepwise selection in increasing concentration of paclitaxel. Cellular morphology, mRNA and protein level of MDR1, BCRP and MRP1 in MCF-7/PR and SKBR-3/PR cells were determined. The expression of Bax, Bcl-2 and miR-21 in parental and paclitaxel-resistant cells was detected by RT-PCR and Western blotting. The synthetic miR-21 inhibitor or miR-21 mimic were transfected into MCF-7/PR, SKBR-3/PR and MCF-7, SKBR-3 cells with Lipofectamine 2000. The miR-21 levels were determined by RT-PCR, and P-gp, Bcl-2 and Bax protein levels were examined by Western blotting. MTT assay was used to measure the cell viability, and flow cytometry was performed to analyze the cell cycle and apoptosis.

RESULTSThe levels of MDR1, BCRP, MRP1, Bcl-2/Bax and miR-21 in MCF-7/PR and SKBR-3/PR cells were significantly higher than those in MCF-7 and SKBR-3 cells. The protein levels of P-gp, Bcl-2 were up-regulated, and Bax was down-regulated compared with parental cells. MiR-21 was significantly down-regulated after miR-21 inhibitor was transfected; and the levels of MDR1, BCRP, MRP1 and Bcl-2/Bax (P <0.05) were also down-regulated. MiR-21 inhibitors significantly suppressed G0/G1 transition of the cell cycle, and induced cell apoptosis in MCF-7/PR and SKBR-3/PR cells. MTT results showed that miR-21 inhibitors induced sensitivity of MCF-7/PR and SKBR-3/PR cells to paclitaxel. And miR-21 mimic can increase the expression of MDR1, Bcl-2/Bax and change cell morphology from parental cells to resistant cells.

RESULTSThe established MCF-7/PR and SKBR-3/PR breast cancer cells show typical multidrug resistance characteristics, which can be used as the model for drug resistance study. Down-regulated miR-21 expression in MCF-7/PR and SKBR-3/PR breast cancer cells can enhance cell sensitivity to paclitaxel.

ATP Binding Cassette Transporter, Sub-Family B ; metabolism ; Apoptosis ; Breast Neoplasms ; metabolism ; Cell Line, Tumor ; Down-Regulation ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; metabolism ; Paclitaxel ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; RNA, Messenger ; Up-Regulation ; bcl-2-Associated X Protein ; metabolism