This paper is aimed to investigate the effect of rest-inserted loading on the mechanosensitivity of osteocytes. In the investigation, cultured MLO-Y4 osteocyte-like cells were strained on cyclic compressive force (CCF) by the self-made compressive loading device. Then we observed the effect of different rest periods-inserted loading (5 s, 15 s, 30 s, respectively) on the mechanosensitivity of osteocytes. We then determined the levels of secreted nitric oxide (NO) and prostaglandin E2 (PGE2) by Griess method and enzyme linked immunosorbent assay (ELISA), respectively. We then stained the cytoskeleton F-actin using immunofluorescence. We found that the expressions of NO and PGE2 in rest-inserted strained groups (> 15 s) were significantly increased compared to those in the continuous strained group. And rest-inserted loading promoted the parallel alignment of stress fibers. It indicates that rest-inserted loading could promote the mechanosensitivity of osteocytes, and this might be related to the parallel alignment of stress fibers.
Actins ; metabolism ; Animals ; Cell Culture Techniques ; Cell Line ; Cytoskeleton ; metabolism ; Dinoprostone ; secretion ; Mice ; Nitric Oxide ; secretion ; Osteocytes ; secretion ; Stress, Mechanical

Objective To explore the expression of miRNA-181a (miR-181a) in patients with multiple myeloma (MM) and its effect on biological features of MM cells. Methods CD138+cells of bone marrow from 25 MM patients and 10 patients with hematological non-malignancies were purified by using immunomagnetic separation, and the expression of miR-181a in CD138+cells and MM cell lines including RPMI 8226, H929 and U266 were detected by real-time quantitative PCR. The effects of down-regulation and up-regulation of miR-181a expression on the biological characteristics of MM cells were studied with miR-181a antagomir and agomir. Results Compared with patients with hematological non-malignant diseases, the expression of miR-181a in CD138+ cells was upregulated in MM patients. Compared with CD138+ cells in hematological non-malignancies, high expressions of miR-181a were observed in RPMI 8226 and U266 myeloma cell line, while low expressions of miR-181a were observed in H929 cells. Down-regulation of miR-181a with 100 nmol/L miR-181a antagomir could inhibit the proliferation of U266 cells at 24,48 and 72 h [(67.1 ± 3.3) %vs. (50.5 ± 4.1) %, (71.5 ± 3.6) % vs. (52.3 ± 2.2) %, (78.1 ± 5.4) % vs. (69.5 ± 4.3) %, P < 0.05 respectively], whereas up-regulation of miR-181a with 100 nmol/L miR-181a agomir could significantly promote the proliferation of H929 cells at 24 h and 48 h [(21.2 ± 2.4) %vs. (38.5 ± 3.6) %, ( 61.3 ± 5.4) %vs. (82.2 ±6.9)%, P<0.01 respectively]. Cell cycle analysis showed that miR-181a antagomir made U266 cell cycle arrest in the G0/G1 phase. Meanwhile, susceptibility test results indicated that the apoptosis of U266 cells induced by doxorubicin, paclitaxel and 5-fluorouracil was increased when the proliferation of miR-181a expression was down-regulated with miR-181a antagomir. In migration assay, the data showed that down-regulation of miR-181a with miR-181a antagomir could inhibit the migration of U266 cells, and the proportion of migrated cells in the experimental group (62 ± 10) %was lower than that in the control group (89 ± 12) %(P< 0.05), whereas up-regulation of miR-181a with miR-181a agomir could improve the migration of H929 cells, and the proportion of migrated cells in the experimental group (242 ± 9) % was higher than that in the control group (98 ± 8)%(P<0.01). Conclusions The high expression of miR-181a expressed highly by MM cells may promote the proliferation, migration and drug resistance of myeloma cells, indicating that miR-181a could be an important prognostic biomarker candidate, and the application of gene silencing may improve the prognosis of MM.

Objective To compare the degree of cell injury induced by 3D protein (SDLY11 and SDLY107) of enterovirus 71 (EV71) strains.Methods EV71 strains SDLY11 and SDLY107 were respectively isolated from children with mild and severe hand foot mouth disease.The target genes 11-3D-Flag and 107-3D-Flag were amplified by reverse transcription-polymerase chain reation (RT-PCR) and inserted into the eukaryotic expression vector pcDNA3.1.The recombinant plasmids 11-3D-Flag-pcDNA3.1 and 107-3D-Flag-pcDNA3.1 were transformed into Escherichia.coli DH5α, respectively, and were identified by enzyme digestion and sequencing.The recombinant plasmids were transfected into rhabdomyosarcoma (RD) cells, respectively.Expression of 3D protein was detected by indirect immunofluorescence assay and western blot.Cell injury induced by 3D protein was detected with lactate dehydrogenase (LDH) test, cell proliferation was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenylthiazolium bromide (MTT) test, and cell apoptosis was detected with Annexin-V and PI.Multiple comparisons among groups were analyzed using LSD-t test if multiple sets of variables were consistent with homogeneity of variance.If not, Dunnett T3 test was used.Results The 1 400 bp fragments were amplified by reverse tramscription (RT)-polymerase chain reaction (PCR), and the recombinant plasmids were digested by enzyme and the 1 400 bp and 5 400 bp fragments were obtained and identified.Gene sequencing showed that the sequences were consistent with the target genes.The specific fluorescence was observed by indirect immunofluorescence assay, and the western blot showed that the molecular weight of the target protein was 55×103.The LDH test showed that the A490 of SDLY11 3D protein transfection group (0.790±0.048) was higher than that of SDLY107 3D protein transfection group (0.641±0.018).The difference was statistically significant (t=5.14, P<0.05).The cell membrane damage caused by SDLY11 3D protein was more severe than SDLY107 3D protein.The MTT test showed that the A570 of SDLY11 3D protein transfection group (1.028±0.020) was lower than that of SDLY107 3D protein transfection group (1.081±0.002), and the difference was statistically significant (t=3.31, P<0.05).The effect on cell proliferation activity of SDLY11 3D protein was greater than SDLY107 3D protein.The results of Annexin-V/PI showed that the percentage of apoptotic cells of SDLY11 3D protein transfection group and SDLY107 3D protein transfection group were (1.471±0.246)% and (1.465±0.237)%, respectively, and the difference was not statistically significant (t=0.04, P=0.973).Conclusions Compared with the SDLY11 3D protein, SDLY107 3D protein induces slighter cell injury, has weaker effect on cell proliferation activity, and is more favorable for virus replication in cells.

OBJECTIVEThe purpose of this study was to investigate the influence of cryogenic treatment and age-hardening heat treatment on the micro-Vicker's hardness of palladium-silver dental alloys.

METHODSA low-gold content dental casting alloy composed of Ag-Pd-Cu-Au was prepared for this study. Experimental specimens according to standard requirements were prepared following a standard dental laboratory casting procedure, cast specimens were heated to 900 degrees C and quenched in ice water. The specimens were then divided into 4 groups. They were subsequently subjected to different treatments, including age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment. The non-treated group was used as control. The micro-Vicker's hardness value was examined. The significance of correlation was analyzed.

RESULTSThe micro-Vicker's hardness of specimens after age-hardening heat treatment, cryogenic treatment, heat treatment combined with cryogenic treatment increased by 129%, 13% and 141%, respectively, compared with that of the non-treated control group. Conclusion Age-hardening heat treatment and cryogenic treatment were effective in elevating the hardness of Ag-Pd-Cu-Au alloy.

To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As2O3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As2O3 induced cell apoptosis, K562 cells were cultured with As2O3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As2O3(2-10 micromol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G2/M phase increased in proportion to As2O3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As2O3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As2O3-induced apoptosis.
Antigens, Neoplasm ; biosynthesis ; genetics ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Humans ; Inhibitor of Apoptosis Proteins ; K562 Cells ; Microtubule-Associated Proteins ; biosynthesis ; genetics ; Neoplasm Proteins ; Oxides ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics

BACKGROUND: Endoplasmic reticulum (ER) stress has been proved to be related to the occurrence of diabetes, dilated cardiomyopathy and neurodegenerative diseases. Indeed, it is closely associated with osteoarthritis. OBJECTIVE: To explore the effect of ER stress on the chondrocyte viability as well as the occurrence and development of osteoarthritis in rats. METHODS: Rat chondrocytes were isolated and cultured, and the ER stress in the rat chondrocytes was by 10 mg/L tunicamycin. The expression levels of ER stress markers C/EBP-homologous protein and 78 kDa glucose-regulated protein were detected by western blot assay, and the proliferation and apoptosis of chondrocytes were detected by cell counting kit-8 assay and AnnexinV-FITC flow cytometry, respectively. In the in vivo experiment, 15 Sprague-Dawley rats were selected and subjected to anterior cruciate ligament transection and medial meniscectomy to establish an animal model of osteoarthritis. Tunicamycin, tauroursodeoxycholic acid and PBS (blank control group) were respectively injected into the articular cavity, and then the progression of osteoarthritis was assessed by hematoxylin-eosin staining at 4 weeks after treatment. RESULTS AND CONCLUSION: After addition of tunicamycin, the expression levels of C/EBP-homologous protein and 78 kDa glucose-regulated protein were significantly upregulated, the viability of chondrocytes was decreased gradually, while the apoptotic rate was increased significantly. Results from gross observation and hematoxylin-eosin staining suggested that tunicamycin promoted the progression of osteoarthritis and tauroursodeoxycholic acid delayed the deterioration of cartilage in the rats. These findings indicate that ER stress results in the decreased chondrocyte viability and increased apoptosis, which may be an important pathogenesis of osteoarthritis. Additionally, tauroursodeoxycholic acid can effectively alleviate osteoarthritis induced by ER stress.

OBJECTIVE: To develop a polymerase chain reaction-sequence specific primer (PCR-SSP) method for simultaneous amplification and identification of the KIR genes among Chinese population. METHODS: Peripheral blood samples from 132 healthy donors who had given blood at Shenzhen Blood Center from January 2015 to November 2015 were selected as the study subjects. Based on the polymorphism and single nucleotide polymorphism (SNP) information of high-resolution KIR alleles in the Chinese population and the IPD-KIR database, specific primers were designed to amplify all the 16 KIR genes and the 2DS4-Normal and 2DS4-Deleted subtypes. The specificity of each pair of PCR primers was verified by using samples with known KIR genotypes. During PCR amplification of the KIR gene, co-amplification the fragment of human growth hormone (HGH) gene by multiplex PCR was used as the internal control to prevent false negative results. A total of 132 samples with known KIR genotypes were randomly selected for blind inspection to verify the reliability of the developed method. RESULTS: The designed primers can specifically amplify the corresponding KIR genes, with clear and bright bands for the internal control and KIR genes. The results of detection are fully consistent with the known results. CONCLUSION The KIR PCR-SSP method established in this study can yield accurate results for the identification of the presence of KIR genes.
Humans ; Receptors, KIR/genetics* ; Reproducibility of Results ; Polymorphism, Genetic ; Genotype ; Multiplex Polymerase Chain Reaction

Objective:To investigate whether endogenous hydrogen sulfide (H2 S)was involved in the pathogenesis of osteoarthritis (OA)and its underlying mechanism,to detect H2 S and its synthases ex-pression in knee cartilage in patients diagnosed with different severity of OA,and to explore the transcrip-tion and expression of gene MMP-13 in chondrocytes treated with IL-1βor H2S.Methods:Synovial fluids of the in-patients with different severity of OA hospitalized in Peking University First Hospital were collected for measurement of H2 S content using methylene blue assay.Articular cartilages of the patients who underwent knee arthroplasty were collected for the cell culture of relatively normal chondrocytes.The chondrocytes were cultured to the P3 generation and H2 S molecular probes were used for detection of endogenous H2 S generation in the chondrocytes.Immunocytochemistry was used to detect the localization of H2 S synthases including cystathionine β-synthase (CBS),cystathionine-γ-lyase (CSE),and mercap-topyruvate sulfurtransferase (MPST)in OA chondrocytes.Western blot was used to quantify the protein expressions of CSE,MPST,and CBS in cartilage tissues of the patients who were diagnosed with OA and underwent knee arthroplasty.The relatively normal human chondrocytes were cultured to passage 3 and then divided into 4 groups for different treatments:(1 )the normal control group,no reagent was added;(2)the IL-1βgroup,5 μg/L of IL-1βwas added;(3)the IL-1β+H2S group,200 μmol/L of NaHS was added 30 min before adding 5 μg/L of IL-1β;(4)the H2 S group,200 μmol/L of NaHS was added. The transcription and expression of gene MMP-13 in chondrocytes of each group were determined with Real-time PCR and Western blot,respectively.And the total NF-κB p65 and phosphorylated NF-κB p65 in chondrocytes were detected with Western blot.Results:The content of H2 S in the synovial fluid of degenerative knee was (14.3 ±3.3)μmol/L.Expressions of endogenous H2 S and its synthases including CBS,CSE and MPST were present in the cytoplasm of chondrocytes.CSE protein expression in Grade 3 (defined by outerbridge grading)cartilage tissues was significantly increased as compared with that of Grade 1 cartilage tissues (1.67 ±0.09 vs.1.26 ±0.11,P<0.05).However,no significant difference of CBS or MPST expression among the different groups was observed.The expression of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (1 .87 ±0.67 vs.0.22 ± 0.10,P<0.05 ),and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (0.55 ±0.11 vs.1.87 ±0.67,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The transcription of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (31.40 ±0.31 vs.1.00 ±0.00,P<0.05), and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (24.41 ± 1.28 vs.31.40 ±0.31,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The total NF-κB p65 in the IL-1βgroup was significantly higher than that in the normal chondrocytes (2.13 ±0.08 vs.0.73 ±0.08,P<0.05),and that in the IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (1 .24 ±0.13 vs.2.13 ±0.08,P<0.05 ),and that in the H2 S group had no significant difference compared with that in the normal control group.The phosphorylated NF-κB p65 in IL-1βgroup was significantly higher than that in the normal chondrocytes (1.30 ±0.13 vs.0.19 ±0.04,P<0.05),and that in IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (0.92 ±0.26 vs.1.30 ±0.13,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.Conclusion:H2 S affected the cartilage degeneration by partly inhibiting the degradation of extracellular matrix.

【Objective】 To investigate the polymorphism of KIR2DL4 gene in northern Chinese Han population. 【Methods】 A total of 327 DNA samples were isolated by magnetic beads from unrelated individuals of northern Chinese Han population. The coding sequence (CDS) of KIR2DL4 were amplified using four pairs of KIR2DL4-specific PCR primers developed by our own KIR sequencing-based typing patent, and each exon of KIR2DL4 carried by the four PCR amplicons was then subjected to DNA Sanger sequencing in both directions. The genotype of each sample was assigned using the Assign 4.7 software. 【Results】 Among 327 individuals, 8 different kinds of KIR2DL4 alleles were detected, with observed frequencies ranked as KIR2DL4^*00102 [77.1%(252/327)], ^*00501 [35.8%(117/327)], ^*011 [20.2%(66/327)], ^*00602 [12.5%(41/327)], ^*00801 [8.6%(28/327)], ^*00103 [4.9%(16/327)], ^*00503 [1.5%(5/327)] and ^*00504 [0.9%(3/327)]. In this study, the 10A type alleles which can encode a full membrane-bound receptor include 2DL4^*00102, ^*00103, ^*00501, ^*00503, ^*00504 and ^*00602, whereas the 9A type alleles which produce truncated forms of receptor include 2DL4^*00801 and ^*011. The observed frequencies for 10A and 9A type KIR2DL4 alleles were 97.6% (319/327) and 27.8% (91/327), respectively. The ratio of 10A to 9A type was 3.5: 1. The observed frequencies of KIR2DL4 alleles in northern Chinese Han population showed no significant difference compared with southern Chinese Han population (P>0.05). 【Conclusion】 The allelic diversity of KIR2DL4 elucidated in the present study can provide valuable data for KIR-associated disease studies and human evolution.

【Objective】 To study the concordance of identifying the presence or absence of KIR genes using flow reverse sequence-specific oligonucleotide probe (Flow-rSSO) hybridization and sequencing based typing-PCR (PCR-SBT) methods. 【Methods】 A total number of 131 cases of DNA samples from Han population were subjected to identify the presence or absence of all 16 KIR genes by Flow-rSSO method, and then sequenced at coding sequence for all 14 functional KIR genes using our in-house KIR PCR-SBT assay. The concordance of identifying the presence or absence of all functional KIR genes by Flow-rSSO and PCR-SBT was analyzed. Samples with inconsistent initial results were re-tested using the Flow-rSSO commercial kits with different Lot number, and further tested using the PCR-SSP commercial kit. 【Results】 The presence or absence of 14 functional KIR genes for 129 of 131 samples were completely in accordance via the PCR-SBT and Flow-rSSO methods. Two samples, one with 3DL1 negative, the other with both 2DS3 and 2DS5 negative initially-identified by Flow-rSSO, were actually all positive tested by PCR-SBT. Further retest by Flow-rSSO commercial kits with different Lot number and PCR-SSP commercial kit indicated that the two samples were all positive, which agreed well with PCR-SBT results. 【Conclusion】 In this paper, the initial test results of the presence or absence of KIR genes identified by Flow-rSSO for 2 samples were wrong, which indicated the importance of carrying out the quality control for reagents in KIR gene testing.