Objective To establish a three-dimensional finite element model of pelvic anteroposterior compression (APC) for analysis of mechanisms for related liganentous damages.Methods A finite element model and a laboratory mechanical model of APC were established using the same pelvic specimens.In a finite element model of normal pelvic bones and ligaments,after the right pelvis was fixated the pubic symphysis (PS) was sectioned.Next,a manual external mobile force was gradually applied to the left hemipelvis to make the PS diastasis 10,20,30,40,60,80 and 100 mm apart.The mechanical experiment revealed the anterior sacroiliac ligament (ASIL) was ruptured when the PS diastasis reached 28 mm.After the strain value of ASIL was calculated through the finite element model,it was applied to the other pelvic ligaments.The displacement in front of the sacroiliac joint (SIJ),stress,strain and extent of injury and disruption of sacrotuberous/sacrospinous ligaments (STL/SSL) with a corresponding PS diastasis were observed and recorded.Results ASIL failed at the point when the PS diastasis was 28 mm and the displacement in front of SIJ was 7.41 ± 1.14 mm.The strain and maximum principal stress of ASIL calculated in the finite element model were 259.5％ and 543.24 MPa respectively.The maximum principal stress value of SSL was 35.00 MPa at the point of failure when the PS diastasis and the displacement in front of SIJ were 51 mm and 15.23 ±2.88 mm,respectively.When the PS diastasis and the displacement in front of SIJ were 100 mm and 7.5 mm respectively,the maximum principal stress value of STL was 16.17 MPa but the strained ligament was not ruptured.When the pelvis was rotated externally step by step,the ASIL failure was followed by the rupture of SSL but not necessarily by the STL failure.Conclusion As the finite element pelvic bone-ligament model established in this study can effectively simulate the mechanisms for APC injury,it can be used to evaluate different extents of pelvic ligamentous injury,providing a basis for the biomechanical study of pelvic bones and ligaments.

Objective To investigate the reliability of using the pubic symphysis diastasis of 25 mm and anterior separation distance of sacroiliac joint to differentiate anteroposterior compression (APC) type Ⅰ and Ⅱ injuries as well as assess the injury severity.Methods A total of 11 (seven males and four females) fresh cadaver specimens with 22 hemipelvis were collected.The pelvic APC injury test models including fixed hemipelvis (restricted group) and unfixed hemipelvis (non-restricted group) were established,with 11 hemipelvis in each group according to the random number table method.Meanwhile the specimens were divided into male group (14 hemipelvis) and female group (eight hemipelvis),simulating APC type injury external rotation hemipelvis.The public symophysis interval and anterior interval of sacroiliac joint of the original pelvis,the pubic symphysis diastasis and anterior diastasis of sacroiliac joint after anterior tibiofibular ligament failure,as well as the affected pelvis ligament and sacral ligament injury were recorded and compared between the restricted and non-restricted groups,male and female groups.Results There were no significant differences in the public symphysis interval of the original pelvis and anterior interval of sacroiliac joint between the restricted group and the non-restricted group (P ＞ 0.05).The pubic symphysis interval of the original pelvis was [(5.13 ± 0.61) mm] in male group and (4.03 ± 0.84)mm] in female group (P ＜ 0.05).When the anterior tibiofibular ligament ruptured,the pubic symphysis diastasis distance was (23.36 ± 7.27) mm,ranging from 12 to 41 mm,and the diastasis distance of anterior sacroiliac joint was (9.82 ± 3.25)mm,ranging from 5 to 18 mm.In terms of the public symphysis interval,there were no significant differences between male and female groups,restricted and the non-restricted groups (P ＞ 0.05).In terms of anterior interval of sacroiliac joint,there was significant difference between male and female groups (P ＜ 0.05) but no significant difference between the restricted and non-restricted groups (P ＞ 0.05).In the restricted group,sacrotuberous ligament injuries were found in four patients,and sacrospinous ligament injuries in five,whhile there were no obvious sacrospinous ligament and sacrotuberous ligament injuries in non-restricted group.There were 10 specimens with the pubic symphysis diastasis ≥23.36 mm and 10 specimens with the diastasis distance of anterior sacroiliac joint ≥9.82 mm (46％),and there were 15 specimens with at least the pubic symphysis interval ≥ 23.36 mm or the anterior interval of sacroiliac joint ≥ 9.82 mm (68％).Conclusions The public symphysis interval ≥ 23.36 mm or anterior interval of sacroiliac joint ≥ 9.82 mm can distinguish anteroposterior compression Ⅰ from Ⅱ injuries,and the combination of the two criteria can be beneficial to assessment of pelvic injury severity.

Objective:To explore expression of VSIG4 in clear cell renal cell carcinoma(ccRCC)and its correlation with immune cells infiltration and prognosis.Methods:RNA-seq data of ccRCC and corresponding clinical data of patients were downloaded from The Cancer Genome Atlas(TCGA)database.Wilcoxon rank-sum test was used to analyze VSIG4 mRNA expression in ccRCC and normal renal tissues.Correlation between VSIG4 expression and clinicopathological parameters was analyzed by Wilcoxon rank-sum or Kruskal-Wallis rank-sum test.Kaplan-Meier method was used to analyze the correlation between VSIG4 expression and progno-sis of patients.Gene set enrichment analysis(GSEA)was used to explore the signaling pathway of VSIG4 in ccRCC.Correlation between VSIG4 level and tumor infiltrating immune cells was analyzed via CIBERSORT in R software.Western blotting was used to detect VSIG4 protein level in human renal epithelial cell line 293T,and human renal carcinoma cell line ACHN,A498,786-O and OS-RC-2.Results:Expression level of VSIG4 in ccRCC was significantly higher than that in normal tissues(P<0.05).VSIG4 expression was significantly correlated with the stages of distant metastasis and lymph node metastasis(P<0.05).Overall survival rate of patients with high VSIG4 expression was significantly lower than that of patients with low expression(P<0.05).GSEA enrichment analysis showed that VSIG4 was mainly enriched in apoptosis,chemokine signaling pathway,cell adhesion molecules and other signaling path-ways.VSIG4 expression was negatively correlated with M1 macrophages(r<0,P<0.05),while positively correlated with M2 macro-phages(r>0,P<0.05).Western blotting results showed that expression of VSIG4 in renal cell carcinoma cells was higher than that in normal renal cells.Conclusion:VSIG4 is highly expressed in ccRCC,and is negatively associated with prognosis,which may become a prognostic biomarker for ccRCC patients.

Objective To explore the effects of proteasome 20S subunit beta 8(PSMB8)on the prolif-eration,migration,and invasion of clear cell renal cell carcinoma(ccRCC)cells and whether PSMB8 promotes tumor progression by activating the mitogen-activated protein kinase kinase(MEK)/extracellular signal-regula-ted kinase(ERK)signaling pathway.Methods The Cancer Genome Atlas was employed to analyze the mRNA levels of PSMB8 in ccRCC and normal tissue,and the expression levels of PSMB8 in ccRCC tissue and cells were determined by real-time quantitative PCR,Western blotting,and immunohistochemistry.Furthermore,the cell lines with stable overexpression and knockdown of PSMB8 were constructed.The CCK-8 assay and colony forma-tion assay were employed to examine the cell proliferation,and the wound healing assay and Transwell assay were employed to examine the invasion and migration of cells.Kyoto Encyclopedia of Genes and Genomes pathway enrich-ment was performed to analyze the co-expressed genes of PSMB8.Western blotting was used to measure the phospho-rylation levels of the proteins in the MEK/ERK signaling pathway.Finally,the rescue experiment was carried out with the ERK agonist C16-PAF.Results Compared with the normal tissue,the ccRCC tissue showed up-regulated mRNA and protein levels of PSMB8(both P＜0.001),which were associated with the TNM stage of patients with ccRCC(P＜0.001).Compared with the negative control group,overexpression of PSMB8 promoted the prolifera-tion(P=0.021,P=0.039),migration and invasion(all P＜0.001)of 786-O and ACHN cells,and the knock-down of PSMB8 inhibited the proliferation(P=0.022,P=0.005),migration and invasion(all P＜0.001)of 786-O and ACHN cells.The pathway enrichment analysis of co-expressed genes of PSMB8 predicted the mitogen-ac-tivated protein kinase signaling pathway(P＜0.001).After the knockdown of PSMB8,786-O and ACHN cells showed lowered phosphorylation levels of MEK1/2(P=0.017,P=0.016)and ERK1/2(P=0.010,P=0.040)and down-regulated transcription levels of ERK downstream factors c-Myc(P=0.043,P=0.038),c-Fos(P=0.025,P=0.008),and CyclinD1(P=0.006,P=0.047).Compared with the ERK agonist C16-PAF group,the PSMB8 knockdown+C16-PAF group showed inhibited proliferation(P=0.003,P=0.002),migration and invasion(all P＜0.001)of 786-O and ACHN cells.Conclusion PSMB8 may promote the proliferation,migration,and invasion of ccRCC cells by activating the MEK/ERK signaling pathway.