Background: Osteosarcoma (OS) is one of the most common primary bone tumors in children and adolescents. However, the molecular mechanism of OS tumorigenesis is still little known. Circular RNA (circRNA) is a key player in the progression of many cancers. This study is performed to decipher the role and mechanism of circ_0008259 in the progression of OS. Methods: A differentially expressed circRNA, circ_0008259, was screened out by analyzing the expression profile of circRNA in OS tissue. Circ_0008259, miR-21-5p and programmable cell death 4 (PDCD4) mRNA expression levels in OS tissues and cells were detected by qRT-PCR. Cell viability, metastatic potential and apoptosis were evaluated by cell counting kit-8 assay, Transwell and flow cytometry. The targeting relationship between circ_0008259 and miR-21-5p, and miR-21-5p and PDCD4 mRNA was analyzed and probed by bioinformatics analysis and dual-luciferase reporter assay, RNA-binding protein immunoprecipitation assay and RNA-pull down assay. The regulatory effects of circ_0008259 and miR-21-5p on PDCD4 protein expression in OS cells were detected by Western blot assay. Results: Circ_0008259 expression and PDCD4 expression were down-regulated and miR-21-5p expression was elevated in the OS tissues and cells. Functional experiments showed that circ_0008259 overexpression significantly inhibited the proliferation and metastatic potential of OS cells and promoted the apoptosis. Besides, PDCD4 was validated as the target gene of miR-21-5p, and circ_0008259 could competitively bind to miR-21-5p, thus up-regulating PDCD4 expression in OS cells. Conclusions: Circ_0008259 suppresses OS progression via regulating miR-21-5p/PDCD4 axis.

The study was aimed at deciphering the function and mechanism of circ_0081001 in osteosarcoma (OS). In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was utilized for quantifying circ_0081001, miR-494-3p, and BTB domain and CNC homolog 1 (BACH1) mRNA expressions in OS tissues and cells. Cell counting kit-8 (CCK-8) assay, together with 5-Ethynyl-2'-deoxyuridine (EdU) assay, was performed for evaluating cell proliferation; the alterations in apoptosis were analyzed utilizing flow cytometry; Transwell assay was conducted for examining cell migration and invasion; moreover, Western blot was utilized for the quantification of BACH1 protein expression; bioinformatics, dual-luciferase reporter gene, and RNA-binding protein immunoprecipitation assays were executed for validating the binding relationships between circ_0081001 and miR-494-3p, and between miR-494-3p and BACH1. As shown, circ_0081001, whose expression was elevated in OS tissues, had a negative association with miR-494-3p expression and a positive correlation with BACH1 expression. After circ_0081001 was overexpressed, the proliferation, migration, and invasion of OS cells were boosted but the apoptosis was reduced, whereas miR-494-3p exhibited opposite effects. The binding sites between circ_0081001 and miR-494-3p, and between miR-494-3p and the 3’UTR of BACH1 were experimentally verified. In conclusion, circ_0081001/miR-494-3p/BACH1 axis promoted the malignant biological behaviors of OS cells.

Objective. This study is aimed at investigating the efficacy and safety of multislice spiral CT-guided transthoracic lung biopsy in the diagnosis of pulmonary nodules of different sizes. Methods. Data of 78 patients with pulmonary nodules who underwent CT-guided transthoracic lung biopsy in our hospital from January 2020 to December 2021 were retrospectively analyzed, and they were divided into the small nodules group ( n = 12 ), medium nodules group ( n = 35 ), and large nodules group ( n = 31 ) according to the diameter of pulmonary nodules. The results of puncture biopsy and final diagnosis of pulmonary nodules of different sizes were compared. The incidence of complications in patients with pulmonary nodules of different sizes was compared. Univariate analysis was used to compare the incidence of complications in 78 patients. Logistic multiple regression analysis was used to analyze the independent risk factors of pneumothorax in patients with pulmonary nodule puncture. Logistic multiple regression analysis was used to analyze the independent risk factors of pulmonary hemorrhage in patients with pulmonary nodule puncture. Results. The diagnostic accuracy, sensitivity, and specificity were 83.33%, 100.00%, and 77.78% in small nodules group. The diagnostic accuracy, sensitivity, and specificity of medium nodules group were 85.71%, 100.00%, and 73.68%, respectively. The diagnostic accuracy, sensitivity, and specificity of large nodules group were 93.55%, 100.00%, and 33.33%, respectively. There was no significant difference in the incidence of pneumothorax among the three groups ( P > 0.05 ). The incidence of pulmonary hemorrhage in small nodule group was higher than that in the medium nodule group and large nodule group, and the difference was statistically significant ( P < 0.05 ). There was no significant difference in the incidence of total complications among the three groups ( P > 0.05 ). There were statistically significant differences in clinical data such as the needle tract length, the puncture position, and the distance of the puncture needle passing through the lung tissue in patients with or without pneumothorax ( P < 0.05 ). There were statistically significant differences in needle tract length, distance of puncture needle passing through lung tissue, and size of pulmonary nodules in patients with or without pulmonary hemorrhage ( P > 0.05 ). Logistic multivariate analysis showed that needle tract length ≤ 50   mm , lateral decubitus position, and the   distance   of   puncture   needle   passing   through   lung   tissue ≥ 14   mm were independent risk factors for pneumothorax after puncture in patients with pulmonary nodules ( P < 0.05 ). The needle tract length > 50   mm , the distance   of   puncture   needle   passing   through   lung   tissue ≥ 14   mm , and small nodules (pulmonary nodules diameter ≤ 10   mm ) were independent risk factors for pulmonary hemorrhage after puncture in patients with pulmonary nodules ( P < 0.05 ). Conclusion. Multislice spiral CT-guided transthoracic lung biopsy is effective in diagnosing pulmonary nodules of different sizes.

It is effective and practical to construct the model of ICA-A base on CTA data. Blood flow simulation of ICA-A will provide new basis for the study on the occurrence and development of aneurysm.

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