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OBJECTIVE: There is lack of an internal fixation following resection of a dumbbell tumor by hemi-laminectomy and facetectomy that achieves adequate stability with less trauma. Unilateral fixation and reconstruction (unilateral pedicle screw and contralateral lamina screw fixation combined with lateral mass reconstruction, UPS + CLS + LM) may be an ideal technique to address this problem. A biomechanical comparison and a case report were designed to evaluate its spinal stability and clinical effect. METHODS: Seven fresh-frozen human subcervical specimens were used for the biomechanical testing. The conditions tested were: (1) intact; (2) injured (single-level hemi-laminectomy and facetectomy); (3) unilateral pedicle screw (UPS) fixation; (4) UPS fixation combined with lateral mass (LM) reconstruction (UPS + LM); (5) UPS fixation and contralateral lamina screw fixation (UPS + CLS); (6) UPS + CLS + LM; (7) UPS fixation and contralateral transarticular screw fixation (UPS + CTAS); (8) bilateral pedicle screw (BPS) fixation. Range of motion (ROM) and neutral zone (NZ) were obtained at C5-C7 segment under eight conditions. In addition, we report the case of a patient with a C7-T1 dumbbell tumor that was treated by UPS + CLS + LM technique. RESULTS: Except left/right lateral bending and right axial rotation (all, p < 0.05), ROM of UPS + CLS + LM condition in other directions was similar to that of BPS condition (all, p > 0.05). There was no significant difference between UPS + CLS + LM and the UPS + CTAS condition in other directions of ROM (all, p > 0.05), except in left/right axial rotation (both, p < 0.05). Compared to UPS + CLS condition, left/right lateral bending ROM of UPS + CLS + LM condition were significantly reduced (both, p < 0.05). UPS + CLS + LM condition significantly reduced ROM in all directions compared to UPS and UPS + LM condition (all, p < 0.05). Similarly, except lateral bending (p < 0.05), there was no difference in NZ in other directions between UPS + CLS + LM and BPS condition (both, p > 0.05). There was no significant difference between UPS + CLS + LM and UPS + CTAS condition in NZ in all directions (all, p > 0.05). Axial rotation NZ of UPS + CLS + LM condition was significantly reduced compared to UPS + CLS condition (p < 0.05). Compared to UPS and UPS + LM condition, NZ of UPS + CLS + LM condition was significantly reduced in all directions (all, p < 0.05). The patient's imaging examination at 3 months postoperatively indicated that the internal fixation did not move and the graft bone was seen with fusion. CONCLUSION: After resection of a dumbbell tumor in the cervical spine, UPS + CLS + LM technique is a reliable internal fixation method to provide sufficient immediate stability and promote postoperative bone fusion.

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Macrophages and microglia play important roles in chronic neuroinflammation following spinal cord injury (SCI). Although macrophages and microglia have similar functions, their phagocytic and homeostatic abilities differ. It is difficult to distinguish between these two populations in vivo, but single-cell analysis can improve our understanding of their identity and heterogeneity. We conducted bioinformatics analysis of the single-cell RNA sequencing dataset GSE159638, identifying apolipoprotein E (APOE) as a hub gene in both macrophages and microglia in the subacute and chronic phases of SCI. We then validated these transcriptomic changes in a mouse model of cervical spinal cord hemi-contusion and observed myelin uptake, lipid droplets, and lysosome accumulation in macrophages and microglia following SCI. Finally, we observed that knocking out APOE aggravated neurological dysfunction, increased neuroinflammation, and exacerbated the loss of white matter. Targeting APOE and the related cholesterol efflux represents a promising strategy for reducing neuroinflammation and promoting recovery following SCI.

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In speaking assessment, many factors such as characteristics of test-takers, test tasks, rating bias, etc. may affect the speaking performance of test-takers. Besides, the stability of raters' rating of a speaking test might pose a threat to its reliability, validity, and fairness, which calls for longitudinal construct validation of the speaking test. This study explores the construct validity of PRETCO-Oral through analysis of data retrieved from various sources, including longitudinal ratings of performances of test-takers across four occasions, and perceptions of the construct of PRETCO-Oral from both raters and test-takers. The results indicate that raters' ratings keep stable and the PRETCO-Oral assessment is equipped with longitudinal reliability; tasks of Interpretation and Presentation represent a large amount of variance of the construct, while those of Reading Aloud and Question and Answer seem to be construct-underrepresented, as evidenced via analyzing the data collected from perceptions of raters and test-takers upon the test construct. Finally, factors that threaten the construct representation are also discussed.