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Objective By comparing the fatigue strength of type A and type B locking compression plates (LCP) in distal femoral plate, a theoretical evaluation method was provided for type selection of bone plate when testing its bending strength and fatigue performance. Methods Through bending strength performance test and fatigue performance test on bone plates with different types, combined with ANSYS Workbench, the finite element analysis on total deformation, von Mises stress and fatigue service life of bone plates were conducted. Results The fatigue strength of type A plate was 30.7% higher than that of type B plate, the stress of type A plate was lower than that of type B plate, and the minimum fatigue service life of type A plate was 17% higher than that of type B plate. Conclusions The fatigue performance of type A plate is better than that of type B plate, so the failure possibility of type A plate was lower than that of type B plate.The results provide references for assisting selection of different bone plates when testing the performance of two newly developed bone plates.
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Objective:To investigate the methylation status of SDC2, PPP2R5C and ADHFE1 genes in stool and their values in the screening of colorectal cancer and precancerous lesions.Methods:From August 2020 to March 2021, 64 patients with colorectal cancer, 72 patients with adenoma, 33 patients with hyperplastic polyps and 59 healthy people were recruited from Qingdao Central Hospital Affiliated to Qingdao University, and the morning stool samples were collected from the research subjects. The genomic DNA was extracted and modified with sulfite. The methylation status of SDC2, PPP2R5C and ADHFE1 genes were detected by methylation specific polymerase chain reaction (MSP), and the fecal occult blood test (FOBT) was performed. Taking the pathological results as the gold standard, receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to compare the effect of combined detection of methylation of three genes and FOBT in predicting colorectal cancer and precancerous lesions. R-Studio software was used to construct a nomogram for the prediction of colorectal cancer with combined detection of gene methylation in stool and other clinical features, and the calibration and validation were performed.Results:The positive rates of combined detection of methylation of SDC2, PPP2R5C and ADHFE1 genes in stool were higher than those of FOBT in colorectal cancer+adenoma [74.3% (101/136) vs. 47.1% (64/136), χ2 = 23.20, P = 0.001], colorectal cancer [90.6% (58/64) vs. 70.3% (45/64), χ2 = 8.91, P = 0.003] and adenoma [59.7% (43/72) vs. 26.4% (19/72), χ2 = 14.43, P = 0.002]. There was no significant difference in the positive rates in hyperplastic polyps [21.2% (7/33) vs. 6.1% (2/33), χ2 = 0.12, P = 0.125] and healthy controls [10.2% (6/59) vs. 8.5% (5/59), χ2 = 4.01, P = 1.000]. The combined detection of gene methylation was better than FOBT in the prediction of colorectal cancer + adenoma [AUC: 0.85 (95% CI 0.80-0.91) vs. 0.71 (95% CI 0.64-0.78), P < 0.05], especially in the prediction of adenoma [AUC: 0.82 (95% CI 0.74-0.89) vs 0.64 (95% CI 0.57-0.69), P < 0.001]. The sensitivity and specificity of ADHFE1 gene methylation status in predicting colorectal cancer were high (90.6% and 96.6%). In colorectal cancer patients over 50 years old, the positive rate of combined detection of gene methylation was higher than that of FOBT [90.2% (55/61) vs. 68.9% (42/61), P < 0.05]. The nomogram calibration curve for predicting colorectal cancer constructed based on the combined detection of gene methylation and each clinical feature showed a high degree of concordance between the predicted and observed diagnostic performance of colorectal cancer. Conclusions:The methylation levels of SDC2, PPP2R5C AND ADHFE1 genes in stool are increased in patients with colorectal cancer or adenoma. The combined detection of gene methylation is expected to be a non-invasive method for the screening of colorectal cancer and precancerous lesions.
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Objective To investigate the effects of costimulatory molecule B7-H3 on the prolifera-tion and invasion of human non-small cell lung cancer cell line A549. Methods Flow cytometry was used to detect the expression of B7-H3 at protein level on A549 cells. B7-H3-targeting siRNA was transfected into A549 by lentivirus to construct B7-H3-A549 cells, which were identified with Western blot and qPCR. Differences in proliferation between B7-H3-A549 and B7-H3+A549 cells were analyzed by CCK8 assay. Flow cytometry was performed to detect the changes in apoptosis and cell cycle after AnnexinⅤ-PE/propidi-um iodide ( PI) staining. Transwell assay was used to evaluate the migration and invasion of B7-H3-A549 and B 7-H 3+ A 549 cells . Expression of apoptosis-related proteins was detected by Western blot . Results (1) B7-H3 was highly expressed on A549 cells. A stable B7-H3-A549 cell line and its control cell line B7-H3+A549 were successfully prepared. (2) A549 cell proliferation was significantly reduced after knocking down B7-H3 expression. (3) The percentage of early apoptotic cells in B7-H3-A549 cell group was higher than that in B7-H3+A549 cell group, but no significant difference in the percentages of cells undergoing late apoptosis was found between the two groups. B7-H3-A549 cells were arrested at the G0/G1 phase of cell cy-cle. (4) Compared with B7-H3+A549 cells, B7-H3-A549 cells showed suppressed migration and invasion. (5) Enhanced expression of Bad and Caspase-3 and decreased expression of Bcl-2, P-AKT and MMP-9 were detected in B7-H3-A549 cells as compared with those in B7-H3+A549 cells, but no significant difference in the total AKT was observed. Conclusions Knocking down the expression of B7-H3 molecule in A549 cells could inhibit cell proliferation and invasion, induce cell cycle arrest at G0/G1 phase and promote cell apoptosis.
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Objective To investigate the feasibility of using leukocytes that were filtered out by LeukoReduction System ( LRS) to replace conventional human peripheral blood leukocytes in experimental researches and to comparatively analyze the differences between them in vitro biological functions and pheno-types of T cells. Methods Mononuclear cells were isolated from LRS-separated leukocytes and whole blood sample that collected from the same person by using Ficoll. Fluorescence-activated cell sorting ( FACS) was performed to analyze the phenotypes of T cells. CD3+T cells were sorted out by using magnetic beads. The T cells that were collected by using two different ways were incubated with anti-CD3 and anti-CD28 antibodies and IL-2 in vitro for 10 days. Several assays including cell counting, FACS and cytometric beads array ( CBA) were performed to comparatively analyze the differences in biological functions and phenotypes of T cells that were isolated by different methods. Results The phenotypes of T cells isolated from LRS filter and whole blood sample were highly similar at the initial stage. The sorting rate of CD3+T cells form LRS filter reached a high level and met the requirements for experimental researches. No statistically significant differ-ences in cell count, phenotype, expression of costimulatory molecules and cytokine secretion were observed between T cells isolated from LRS filter and whole blood sample. Conclusion This study suggested that the T cells isolated from LRS filter could be used as an alternative to whole blood T cells for fundamental resear-ches since they were similar in cell vitality, phenotype and biological functions. It provided a new way to solve the problem of blood shortage in clinic and scientific research.
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<p><b>OBJECTIVE</b>To evaluate the impact of macroscopic enlarged lymph node on the clinicopathological characteristics of stage II colorectal cancer, and to explore the potential mechanism.</p><p><b>METHODS</b>Clinicopathological data of 116 consecutive patients with stage II colorectal cancer, who underwent colorectal radical resection and were identified as stage II colorectal cancer without mesenteric metastasis by postoperative pathology, in our department between December 2001 and December 2002 were analyzed retrospectively. All the patients were examined by the surgeons with gross appearance to decide the enlarged lymph nodes as metastasis during operation. There were 43 patients with macroscopic enlarged lymph nodes and 73 without such lymph nodes. Survival rate was compared between the two groups. Impact of macroscopic enlarged lymph node on the prognosis of stage II colorectal cancer was analyzed. Structure of macroscopic enlarged lymph node was observed. CK expression in 107 macroscopic enlarged lymph nodes from 43 cases was examined by immunohistochemistry.</p><p><b>RESULTS</b>The 10-year disease-free survival (DFS) of the whole group was 83.5%. The 10-year DFS of patients with macroscopic enlarged lymph nodes was 75.9%, which was significantly lower than 89.3% (P=0.038) of patients without macroscopic enlarged lymph nodes. Univariate analysis showed that macroscopical enlarged lymph node (P=0.038), perioperative blood transfusion (P=0.004), number of retrieved lymph nodes (P=0.016), concomitant disease (P=0.003), and preoperative serum carcinoembryonic antigen (CEA) level (P=0.050) were related to the prognosis of all the 116 patients. Multivariate analysis showed that macroscopical enlarged lymph node (P=0.044), number of retrieved lymph nodes (P=0.021), and perioperative blood transfusion (P=0.032) were independent prognostic factors. Haematoxylin and eosin (HE) staining indicated that enlarged lymph nodes had hyperplasia reaction. Immunohistochemistry showed that among 107 enlarged lymph nodes, 1 had macrometastases, 1 micrometastasis, 4 isolated tumor cell (ITC), and the rest 101 had no positive CK expression.</p><p><b>CONCLUSION</b>Macroscopic enlarged lymph node indicates a poor prognosis in patients with stage II colorectal cancer.</p>