Search

Objective: To investigate whether miR-483-5p regulates osteoclast generation by targeting Timp2. miR-483-5p can promote osteoclast differentiation and bone destruction. Methods: Target genes of miR-483-5p were predicted by miRNAs target gene prediction software TargetScan8.0, and wild type and mutant 3' UTR plasmids were constructed. Dual luciferase reporter genes were used to verify whether target genes had a targeted regulatory relationship with miR-483-5p. Western blotting was used to detect the corresponding changes in the expression level of target protein after adjusting the level of miR-483-5p in cells. Cells were transfected or infected with target gene siRNA or target protein lentivirus, and TRAP staining and q-PCR assays were performed. In addition, for osteoclast induction experiment, RAW264.7 cells were co-transfected with ago-miR-483-5p and target protein-overexpressed lentiviruses q-PCR and TRAP staining were performed respectively. Results: Bioinformatics software was used to predict the target gene of miR-483-5p, and the Timp2 gene was found to regulate osteoclasts, and the dual luciferase reporter detection system found that miR-483- 5p could be associated with the 3-UTR of the predicted target gene Timp2 gene. There are complementary loci and targeted regulatory relationship between them. Subsequently, we upregulated miR-483-5p in RAW264.7 cells to reduce the expression of Timp2. Compared with the normal group, the number of osteoclasts and the expression of osteoclast-specific genes increased significantly after the induction of Timp2 in knockdown cells. After co-transfection of target gene and miR-483-5p into cells, the number of osteoclasts and the expression of specific genes decreased significantly compared with the normal group. Conclusion: Timp2 is a downstream target gene of miR-483-5p and is involved in and inhibits osteoclast generation. [ABSTRACT FROM AUTHOR]

In inter-satellite laser communication, four-quadrant detector is often used in precise tracking unit for spot location. The positioning error directly affects the angular measurement accuracy of fine tracking unit. In order to achieve the tracking precision of micro-radian magnitude, this paper studies various noise factors that affect the positioning accuracy of the detector, simplifying the analysis according to the practice of inter-satellite laser communication, and putting forward the specific calculation method of positioning error. Finally, we evaluate the influence degree of each factor through a specific example. The results show that the signal-to-noise ratio of the received signal increases with the increasing of emitting power in a certain range with reduced positioning error. However, positioning error does not decrease linearly with the increase of transmitting power. When the transmitting power increases to a certain extent, the reduction of tracking error is limited. At this time, it will be very expensive to improve the tracking precision simply by increasing the transmitting power. [ABSTRACT FROM AUTHOR]

Objective: To analyze the correlation between the Kellgren–Lawrence (K‐L) score of knee osteoarthritis (KOA) patients with different degrees and their urine concentration of C‐terminal telopeptide of collagen type II (CTX‐II) and interleukin‐1β (IL‐1β), and to further evaluate the diagnostic value of CTX‐II and IL‐1β during the pathological process by producing an experimental osteoarthritis (OA) model in rabbits. Methods: From 1 January 2017 to 31 December 2018, a total of 34 subjects (7 mild, 9 moderate, 9 severe arthritis patients, and 9 healthy individuals) comprising 16 men and 18 women were included in this study. Patients were diagnosed according to the American College of Rheumatology (ACR) criteria. The urine of all subjects was collected to detect the concentration of CTX‐II and IL‐1β. The rabbits in the KOA group were subjected to protease (control group with saline) injection into the articular cavity of their right knees and immobilization with gypsum. We used radiological and histological examination to identify the KOA model. ELISA was applied to investigate the concentrations of CTX‐II and IL‐1β in urine and serum, and Spearman's rank correlation analysis was used to analyze the correlation. Results: There was no significant difference in the mean ages and body mass index (BMI) between groups. The mean ages of mild, moderate, and severe arthritis patients and healthy individuals were 54.29 ± 5.76, 58.44 ± 6.44, 59.89 ± 6.75, and 56.67 ± 4.18 years, respectively. The mean BMI of mild, moderate, and severe arthritis patients and healthy individuals were 23.59 ± 1.56, 23.57 ± 2.06, 24.46 ± 1.64, and 23.42 ± 1.35 kg/m2, respectively. The Kellgren–Lawrence (K‐L) score was higher with the aggravation of KOA. The K‐L scores of mild, moderate, and severe KOA patients were 1.14 ± 0.38, 2.56 ± 0.53, and 3.63 ± 0.52, respectively. The KOA symptoms of patients became more severe, with not only increased K‐L scores but also elevated concentrations of CTX‐II and IL‐1β. Moreover, there was a positive correlation between CTX‐II and IL‐1β of all subjects (r = 0.974, P < 0.001), between K‐L score and urine concentration of CTX‐II (r = 0.900, P < 0.001), and between K‐L score and IL‐1β (r = 0.813, P < 0.001) of all subjects. Both were significantly increased in KOA group rabbits at all time points after surgery. The serum concentration of CTX‐II and IL‐1β was elevated as early as in the 2nd week (3.69 and 4.25 times) and reached a peak (5.41 and 7.23 times) in the 4th week after surgery. Then, until 12 weeks after surgery, the CTX‐II and IL‐1β concentrations in the KOA group were slightly reduced and remained around 4.5 and 6.3 times that in the control group. Moreover, there was a positive correlation between the serum concentration of IL‐1β and CTX‐II (r = 0.967, P < 0.001). Conclusion: CTX‐II and IL‐1β, which were significantly increased during the process of KOA, can be used as biomolecular markers to provide guidelines for early diagnosis and treatment of KOA. [ABSTRACT FROM AUTHOR]