Objective:To investigate the clinical incidence of the three mesial root canals of mandibular first molars. Methods: Incidence and morphology of the three mesial root canals of mandibular first molars were determined by probing the fissure or grooves between the mesiobuccal and mesiolingual root canal orifices and X-ray analysis. Results: Of the 222 mandibular first molars, 13 of the molars had three mesial root canals. The incidence rate was 5.85 %. Conclusion: Although the incidence rate of the three mesial root canals of mandibular first molars was very low, the dental operative microscope was helpful for the diagnosis.

The contents of trace elements,amino acids and proteins in Asterias rollestoni shell were determined in this study. The result showed that a large of contents of inorganic elements - Ca, Mg, P, Cs, Sr., and essential - Zn, Sn, Mn, Fe, Ge, Cu trace elements were contained in Asterias rollestoni shell. Moreover,amino acids 17. 02%,proteins 19. 6% were analysed with Asterias rollestoni shell in our experimentation.

Objective:To investigate the expressions of miR-20a-5p and lysine (K) demethylase 6B (KDM6B) in osteosarcoma tissues and the effects of miR-20a-5p targeting KDM6B on the proliferation, migration and invasion of osteosarcoma cells and tumor growth.Methods:The clinicopathological and paracancerous tissues of 20 patients with osteosarcoma admitted to the First Affiliated Hospital of Chinese Medical University from January 2017 to March 2019 were collected. Quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of miR-20a-5p and KDM6B mRNA in tissues. The osteosarcoma MG63 cells were divided into control group, mimic NC group, miR-20a-5p mimic group, and NC+ empty vector group, miR-20a-5p+ empty vector group, miR-20a-5p+ KDM6B group. The expression levels of miR-20a-5p and KDM6B mRNA of all groups were detected by qRT-PCR. Western blotting was used to detect the expression level of KDM6B. CCK-8 assay, cell scratch test and Transwell test were used to detect cell proliferation, migration and invasion ability. According to the random number table method, nude mice were divided into NC+ empty vector group, miR-20a-5p+ empty vector group and miR-20a-5p+ KDM6B group, with 5 mice in each group. Tumor growth ability was detected by tumor xenograft nude mouse models.Results:The relative expression level of miR-20a-5p mRNA in osteosarcoma tissues was 0.55±0.27, and that in paracancerous tissues was 1.22±0.28, with a statistically significant difference ( t=7.701, P<0.001). The relative expression level of KDM6B mRNA in osteosarcoma tissues was 1.66±0.19, and that in paracancerous tissues was 1.00±0.15, with a statistically significant difference ( t=12.219, P<0.001). After transfection of miR-20a-5p, KDM6B mRNA and protein expression levels decreased with the increase of miR-20a-5p expression level. After miR-20a-5p transfection for 48 h, the cell proliferation abilities of the blank control group, mimic NC group and miR-20a-5p mimic group were 0.83±0.04, 0.81±0.03 and 0.52±0.01 ( F=89.655, P<0.001), compared with the blank control group and mimic NC group, the cell proliferation ability was significantly inhibited in the miR-20a-5p mimic group (both P<0.001). The cell proliferation abilities of NC+ empty vector group, miR-20a-5p+ empty vector group and miR-20a-5p+ KDM6B group were 0.83±0.05, 0.52±0.01 and 0.67±0.05 ( F=43.919, P<0.001), compared with the NC+ empty vector group, the cell proliferation ability was significantly inhibited in the miR-20a-5p+ empty vector group ( P<0.001); compared with the miR-20a-5p+ empty vector group, the cell proliferation ability of miR-20a-5p+ KDM6B group increased significantly ( P<0.001). The scratch healing rates of the blank control group, mimic NC group and miR-20a-5p mimic group were (32.51±2.73)%, (30.26±3.22)% and (13.52±1.77)% ( F=46.314, P<0.001), compared with the control group and the mimic NC group, the scratch healing rate of the miR-20a-5p mimic group was significantly decreased (both P<0.001). The scratch healing rates of NC+ empty vector group, miR-20a-5p+ empty vector group and miR-20a-5p+ KDM6B group were (31.34±3.11)%, (12.15±1.64)% and (28.93±2.89)% ( F=47.511, P<0.001), compared with the NC+ empty vector group, the scratch healing rate of the miR-20a-5p+ empty vector group was significantly decreased ( P<0.001); compared with the miR-20a-5p+ empty vector group, the scratch healing rate of miR-20a-5p+ KDM6B group was significantly increased ( P=0.001). The numbers of transmembrane cells in the blank control group, mimic NC group and miR-20a-5p mimic group were 114±16, 108±11 and 42±6 ( F=36.282, P<0.001), compared with the control group and mimic NC group, the number of transmembrane cells of the miR-20a-5p mimic group was significantly decreased (both P<0.001). The numbers of transmembrane cells in the NC+ empty vector group, miR-20a-5p+ empty vector group and miR-20a-5p+ KDM6B group was 143±11, 39±4 and 139±12 ( F=112.120, P<0.001), compared with the NC+ empty vector group, the number of transmembrane cells of the miR-20a-5p+ empty vector group was significantly decreased ( P<0.001); compared with the miR-20a-5p+ empty vector group, the number of transmembrane cells of the miR-20a-5p+ KDM6B group was increased significantly ( P<0.001). The tumor volumes of mice for 21 d in the NC+ empty vector group, miR-20a-5p+ empty vector group and miR-20a-5p+ KDM6B group were (1 667.50±250.40) mm 3, (129.20±21.00) mm 3 and (775.41±77.51) mm 3 respectively, with a statistically significant difference ( F=77.651, P<0.001). The tumor weights of the 3 groups were (1.35±0.18) g, (0.12±0.01) g and (0.61±0.03) g respectively, with a statistically significant difference ( F=104.191, P<0.001). Conclusion:The expression of miR-20a-5p is significantly decreased in osteosarcoma tissues, and the expression of KDM6B is significantly increased in osteosarcoma tissues. Overexpression of miR-20a-5p may inhibit the proliferation, migration and invasion of osteosarcoma cells and tumor growth by targeting to reduce the expression of KDM6B.

In this study, CD133+ subpopulations were isolated from 41 primary colorectal cancer tissues, the proliferation and cell cycle distribution of the cells were examined without in vitro expansion, and then compared to those of cell lines. The detection of CD133 in colorectal cancer tissues, isolation of CD133+ and CD133- epithelial subpopulations, Ki-67/DNA multiparameter assay and cell volume analysis were flow cytometrically conducted. The results showed that Ki-67 expression was correlated with CD133 level in primary cancer tissues, while cell cycle G2/M phase distribution or clinicopathological characteristics was not. In addition, the CD133+ cells showed larger cell volume and higher Ki-67 expression as compared with CD133- cells. But there was no statistically significant difference in G(2)/M phase distribution between the two subpopulations. Our results demonstrated that the CD133+ subpopulation in colorectal cancer tissue contained more actively cycling and proliferating cells, which was not correlated to clinicopathological factors but might contribute to tumor progression and poor clinical outcome.

Objective To investigate the establishment,operation and performance of external quality assessment(EQA) system for microbial morphology and detection of special drug-resistance in clinical laboratory,and explore the value of the developed system in clinical application.Methods The pictures of known bacteria and fungi colony,gram staining and acid-fast staining from clinical microbiology were distributed to the participating laboratories in Gansu province twice a year at regular intervals.The pictures of standard knowledge points from CLSI,such as special drug resistance were distributed simultaneously.All the participating laboratories were required to complete the interpretation for the pictures and report their resuhs in a scheduled time.Then the resuhs were summarized and analyzed as 3 modes:complete consistency,general consistency and non-consistency.Results During the 2 years when the EQA system for microbial morphology and detection of special drug-resistance were performed for 24 times,the rate of annual complete consistency increased year by year and reached to 91.3％ in 2015.Conclusion The EQA system based on the examinations of microbial morphology and CLSI standard knowledge points for clinical laboratory may supervise the staff of clinical microbiology laboratories in the hospitals at second grade or above to master the skills of morphological identification and learn CLSI knowledge points,so their professional skills of clinical microbiology could be comprehensively improved.

Exosomes are extracellular microbubbles related to intercellular communication, which have the ability to transport and transfer biological macromolecules. Pain will lead to a sharp decline in the quality of life of patients, and will give patients and society a heavy medical burden. More and more evidences show that the exosomes plays an important role in the pathological process of pain related diseases.Summarizing the exosomes and the biomolecules carried by them under different pain conditions, and identifying the specific exosomes related to the pain state will be helpful for early diagnosis and treatment of pain related diseases. In addition, the ability of exosomes to transmit information and its widespread characteristics in the body indicate that they have broad prospects as a new diagnosis and treatment tool in the field of pain. A better understanding of the relationship between the exosomes and pain will provide a novel and promising treatment for patients with pain.

Osteosarcoma is the most common malignant bone tumor disease in young children and young people. It usually has strong invasiveness, and conventional treatment cannot achieve the expected results. Therefore, studying the mechanism of tumor cell death and exploring more effective treatment methods is of great significance. As a new form of cell death, ferroptosis has been found to have three main regulatory pathways closely related to tumor cell molecular mechanisms, genes, etc. This provides a theoretical basis for the application of ferroptosis in the treatment of osteosarcoma. This article reviews recent research on the interaction between ferroptosis and osteosarcoma in regulating molecules, genes, and other factors, as well as the application of ferroptosis in the treatment of osteosarcoma.

This study sought to determine the impact of dental fluorosis severity on demineralization and remineralization of human fluorosed teeth in vitro. Surface enamel microhardness was measured on the enamel blocks before and after demineralization and after remineralization. The results showed that after demineralization, the sequence of % Surface microhardness demineralization (% SMHD) was TFI4 (18.92 +/- 1.31) < TFI3 (20.50 +/- 1.32) < TFI2 (25.08 +/- 1.69) < TFI1 (27.77 +/- 1.79) < TFI0 (30.70 +/- 1.35) (P < 0.05), and there was no statistically significant differences between TFI1 (27.77 +/- 1.79) and the normal group TFI0 (30.70 +/- 1.35). After remineralization, the sequence of % Surface microhardness remineralization (% SMHR) was TFI1 (55.17 +/- 1.23) > TFI0 (53.97 +/- 3.05) > TFI2 (49.17 +/- 1.81) > TFI3 (44.85 +/- 1.89) > TFI4 (36.51 +/- 2.95) (P < 0.05). Moderately fluorosed enamel showed a significatnt resistance to caries, but mildly fluorosed enamel could get better remineralization. These facts and figures deserve clinicians' attention.
Dental Enamel ; chemistry ; pathology ; Fluorosis, Dental ; metabolism ; Humans ; In Vitro Techniques ; Tooth Demineralization ; Tooth Remineralization

BACKGROUND:Recently, there are many documents al over the world reporting hypotoxicity infection after fracture internal fixation surgery, but reports are different on whether it is necessary for chronic hypotoxicity infection internal fixation removal post surgery. There are no fixed judgment criteria of curative effects, which leads to inexact conclusion of treatment method. ＜br> OBJECTIVE:To observe the curative effects of taking rifampicin and ciprofloxacin with transfer of skin flap in the treatment of chronic hypotoxicity infection with sinus formation after fracture surgery on tibial plateau and ankle. METHODS:A total of 56 cases of chronic hypotoxicity infection after fracture surgery of tibial plateau and ankle were col ected from September 2005 to December 2012. 30 cases in the therapy group were treated with ＜br> levofloxacin and rifampicin with transfer of skin flap. 26 cases in the control group were treated with conventional intravenous antibiotics with local debridement to remove internal fixation. In both groups, the course of disease was 3 to 6 months. The erythrocyte sedimentation rate, kidney function and radiographic indices were reviewed every 1 to 3 months, and curative effects were evaluated. ＜br> RESULTS AND CONCLUSION:During the fol ow-up visit of 6-24 months, no recurrence happened to the cured and improved patients. In the therapy group, 24 cases were cured, 4 cases were improved, and 2 cases were invalid, with a total effective rate of 93%. In the control group, 11 cases were cured, 6 cases were improved and 9 cases were invalid with the total effective rate of 65%.χ2 test showed that therapeutic effects were significantly better in the therapy group than in the control group (P＜0.05). These data indicated that rifampicin and ciprofloxacin with transfer of skin flap for chronic hypotoxicity infection with sinus formation after fracture surgery of tibial plateau and ankle showed good curative effects.