Associations of residential greenness with bone mineral density and osteoporosis: the modifying effect of genetic susceptibility.

OBJECTIVES: To investigate the associations of residential greenness with bone mineral density and incident osteoporosis, and further evaluate the potential modifying effect of genetic susceptibility. METHODS: We used the Normalised Difference Vegetation Index (NDVI) at various buffer distances, including 300 m (NDVI300m), 500 m (NDVI500m), 1000 m (NDVI1000m) and 1500 m (NDVI1500m), to serve as indicators of greenness. We fitted linear regression, logistic regression and Cox proportional hazard models to assess the associations of residential greenness with estimated bone mineral density (eBMD), prevalent osteoporosis and incident osteoporosis, respectively. With the Polygenic Risk Score (PRS) for osteoporosis, we further assessed the joint effects of genetic risk and greenness on the risk of osteoporosis. We conducted causal mediation analyses to explore potential mediators. RESULTS: Each IQR increase in NDVI300m was associated with 0.0007 (95% CI 0.0002 to 0.0013) increase in eBMD, 6% lower risk of prevalent osteoporosis (OR 0.94; 95% CI 0.92 to 0.97) and 5% lower risk of incident osteoporosis (HR 0.95; 95% CI 0.93 to 0.98). The joint effects of greenness and PRS on the risk of osteoporosis displayed a clear dose-response pattern. Compared with individuals exposed to low NDVI levels and high genetic risk, those exposed to high NDVI levels and low genetic risk had a 56% (95% CI 51% to 61%) lower risk of osteoporosis. The primary mediators in the association between greenness and incident osteoporosis were identified as PM2.5 and NO2. CONCLUSIONS: Residential greenness was associated with higher bone mineral density and decreased risk of incident osteoporosis.

Bizarre parosteal osteochondromatous proliferation in the distal ulna where the lesion is continuous with the medullary cavity: a case report.

BACKGROUND: Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign bone tumor, it is also called "Nora's lesion". The lesion is characterized by heterotopic ossification of the normal bone cortex or parosteal bone. The etiology of BPOP is unclear and may be related to trauma. In most BPOPs, the lesion is not connected to the medullary cavity. Here we report an atypical case, characterized by reversed features compared to the typical BPOP, which demonstrated continuity of the lesion with the cavity. CASE PRESENTATION: An 11-year-old female child had a slow-growing mass on her right wrist for 8 months with forearm rotation dysfunction. Plain X-rays showed an irregular calcified mass on the right distal ulna, and computed tomography (CT) showed a pedunculated mass resembling a mushroom protruding into the soft tissue at the distal ulna. The medulla of this lesion is continuous with the medulla of the ulna. A surgical resection of the lesion, together with a portion of the ulnar bone cortex below the tumor was performed, and the final pathology confirmed BPOP. After the surgery, the child's forearm rotation function improved significantly, and there was no sign of a recurrence at 1-year follow-up. CONCLUSION: It is scarce for BPOP lesions to communicate with the medullary cavity. However, under-recognition of these rare cases may result in misdiagnosis or inappropriate treatment thereby increasing the risk of recurrence. Therefore, special cases where BPOP lesions are continuous with the medulla are even more important to be studied to understand better and master these lesions. Although BPOP is a benign tumor with no evidence of malignant transformation, the recurrence rate of surgical resection is high. We considered the possibility of this particular disease prior to surgery and performed a surgical resection with adequate safety margins. Regular postoperative follow-up is of utmost importance, without a doubt.

Endoprosthetic replacement with preservation of the epiphysis for proximal tibial reconstruction after osteosarcoma resection in children: a case report.

BACKGROUND: Limb salvage surgery is an important method for treating malignant tumors of the bone involving the adjacent parts of the major joints in children. This technique allows for preservation of limb function, especially in the lower limb. However, the reconstruction of the proximal end of the tibia after removing the tumor mass with a rational scale to preserve the total knee joint and reduce limb length discrepancy presents a challenge. CASE PRESENTATION: We present a case of osteosarcoma of the proximal tibia. After being treated with an extended tumor resection, the proximal tibia of the child was restructured using endoprosthetic replacement with epiphyseal preservation. This procedure preserves the entire articular surface and growth plate of the knee joint of the affected limb and provides a feasible alternative protocol for retaining the function and growth potential of the affected limb. The patient remained disease-free and normal limb motor function was observed during the 3.5 year follow-up since the initial surgery. CONCLUSIONS: Preservation of the epiphysis enabled our patient to perform better limb function after limb-saving surgery as a result of his undamaged knee joint and minimized limb-length discrepancy. We believe that endoprosthetic replacement with preservation of the epiphysis can provide the best strategy for reconstruction after resection of focal malignant tumors in long bones without epiphytic involvement.

Light environment affects the efficiency of surgical suture training.

BACKGROUND: Suture knotting is the basis of surgical skills. In the process of surgical skills learning, the surrounding environment, especially the light, will affect the efficiency of learning. This study investigated the effect of optical environment on the learning of stitching and knotting skills. METHODS: A total of 44 medical students were randomly divided into four groups and participated in the study of suture knotting in four different optical environments. During the process, we assess objective pressure level by testing salivary amylase activity Likert scale and objective structured clinical examination (OSCE) was used to estimate the subjective psychological state and overall skill mastery in surgical suturing respectively. RESULTS: Under high illumination conditions (700 lx), the salivary amylase activity of the high color temperature group (6000 K) was significantly higher than that of the low color temperature group (4000 K) (p < 0.0001). Similarly, under low illumination (300 lx), the salivary amylase activity of the high color temperature group was also significantly higher than that of the low color temperature group (p < 0.05). The student under high illumination conditions (700 lx) and the low color temperature (6000 K) have an autonomy score between 37-45, which is significantly higher compared to the other three groups (p < 0.0001). Group 2 has an average OSCE score of 95.09, which were significantly higher than those of the other three groups (p < 0.05). CONCLUSION: High illumination combined with low color temperature is considered as the optimal training conditions, promoting trainees' optimism, reducing stress levels, and enhancing learning efficiency. These results highlight the pivotal role of light environment in improving the quality and efficiency of surgical skills training.

Inhibition of NF-κB and ERK signaling pathways in osteoclasts and M1 macrophage polarization: Mechanistic insights into the anti-osteoporotic effects of Pseudolaric acid B.

Osteoporosis, characterized by bone metabolism disruption leading to gradual bone loss and increased fracture susceptibility, is linked to the excessive activation of osteoclasts. Pseudolaric acid B (PAB), identified as an NF-κB signaling inhibitor crucial for osteoclastogenesis, is explored here for its protective effects in osteoporosis. Noncytotoxic PAB's impact on osteoclast differentiation was assessed through cell viability and osteoclast formation assays, with subsequent testing of osteoclast function via bone resorption assays. Quantitative real-time polymerase chain reaction evaluated PAB's genetic-level impact on osteoclastogenesis. Network pharmacology, western blot, and luciferase reporter gene assays were employed to elucidate PAB's regulatory mechanism. In an in vivo model of osteoporosis induced by ovariectomy (OVX) in mice, micro-CT, H&E staining, and TRAP staining facilitated histomorphometry analysis, while flow cytometry verified macrophage polarization. PAB demonstrated inhibitory effects on osteoclast formation and bone resorption in BMM and RAW264.7 cells, suppressing osteoclast-specific genes. Bioinformatic analysis, western blot, and luciferase assay results indicated PAB's inhibition of IκBα phosphorylation in the NF-κB signaling pathway and ERK in MAPKs, elucidating its mechanism. In vivo experiments confirmed PAB's attenuation of osteoporosis by reducing osteoclast formation in OVX mice. PAB further facilitated macrophage conversion from M1 to M2 and suppressed IL-1ß, TNF-α, and IL-6 synthesis. In conclusion, PAB prevents osteoporosis by inhibiting RANKL-induced osteoclastogenesis through NF-κB and ERK signaling pathway suppression, coupled with macrophage polarization. These findings indicate the potential therapeutic role of PAB in osteoporosis.

TiO2 nanotube topography enhances osteogenesis through filamentous actin and XB130-protein-mediated mechanotransduction.

TiO2 nanotube topography, as nanomechanical stimulation, can significantly promote osteogenesis and improve the osteointegration on the interface of implants and bone tissue. However, the underlying mechanism has not been fully elucidated. XB130 is a member of the actin filament-associated protein family and is involved in the regulation of cytoskeleton and tyrosine kinase-mediated signalling as an adaptor protein. Whether XB130 is involved in TiO2 nanotubes-induced osteogenic differentiation and how it functions in mechano-biochemical signalling transduction remain to be elucidated. In this study, the role of XB130 on TiO2 nanotube-induced osteogenesis and mechanotransduction was systematically investigated. TiO2 nanotube topography was fabricated via anodic oxidation and characterized. The osteogenic effect was significantly accelerated by the TiO2 nanotube surface in vitro and vivo. XB130 was significantly upregulated during this process. Moreover, XB130 overexpression significantly promoted osteogenic differentiation, whereas its knockdown inhibited it. Filamentous actin depolymerization could change the expression and distribution of XB130, thus affecting osteogenic differentiation. Mechanistically, XB130 could interact with Src and result in the activation of the downstream PI3K/Akt/GSK-3ß/ß-catenin pathway, which accounts for the regulation of osteogenesis. This study for the first time showed that the enhanced osteogenic effect of TiO2 nanotubes could be partly due to the filamentous actin and XB130 mediated mechano-biochemical signalling transduction, which might provide a reference for guiding the design and modification of prostheses to promote bone regeneration and osseointegration. STATEMENT OF SIGNIFICANCE: TiO2 nanotubes topography can regulate cytoskeletal rearrangement and thus promote osteogenic differentiation of BMSCs. However, how filamentous actin converts mechanical stimulus into biochemical activity remains unclear. XB130 is a member of actin filament-associated protein family and involves in the regulation of tyrosine kinase-mediated signalling. Therefore, we hypothesised that XB130 might bridge the mechano-biochemical signalling transduction during TiO2 nanotubes-induced osteogenic differentiation. For the first time, this study shows that TiO2 nanotubes enhance osteogenesis through filamentous actin and XB130 mediated mechanotransduction, which provides new theoretical basis for guiding the design and modification of prostheses to promote bone regeneration and osseointegration.

The mitotic rate as a prognostic biomarker after preoperative radiotherapy for high-grade limb/trunk soft tissue sarcoma.

PURPOSE: Currently there is no generally accepted standardized approach for the pathologic evaluation of soft tissue sarcoma (STS) histology appearance after preoperative radiotherapy (PORT). This study aimed to investigate the prognostic value of pathological appearance after PORT for patients with high-grade limb/trunk STS. METHODS: A cohort of 116 patients with high-grade STS of the limb/trunk treated with PORT followed by resection were evaluated. Patient characteristics, imaging tumor morphology (size, volume), and histopathology (mitotic and necrosis rate, viable cell, hyalinization/fibrosis cytopathic effect) were reviewed and reassessed. Disease free survival (DFS) and overall survival (OS) were calculated using the Kaplan-Meier method, and the hazard ratio was derived from Cox proportional hazard models. Two predictive nomograms were calculated based on significant predictors identified. RESULTS: The 5-year DFS and OS were 52.9% and 70.3%, respectively. Tumor size before (HR:1.07, 95%CI: 1.01-1.14) and after PORT (HR:1.08, 95%CI: 1.01-1.14), tumor volume (HR:1.06, 95%CI: 1.01-1.12), mitotic rate after PORT (HR: 1.06, 95%CI: 1.02-1.11), mitotic rate change after PORT (HR:1.04, 95%CI:1.00-1.09) were independent risk factors for DFS. Tumor size before (HR:1.08, 95%CI: 1.03-1.14) and after PORT (HR:1.09, 95%CI: 1.04-1.15), tumor volume (HR:1.05, 95%CI: 1.01-1.09), mitotic rate after PORT (HR: 1.09, 95%CI: 1.04-1.13), mitotic rate change after PORT (HR:1.05, 95%CI:1.01-1.09) were independent risk factors for OS. The C-index of pathologic predictive nomogram based on mitotic rate for DFS and OS were 0.67 and 0.73, respectively. The C-index of morphology-pathology predictive nomogram for OS was 0.79. CONCLUSION: Tumor size before and after PORT, tumor volume, mitotic rate after PORT, mitotic rate change after PORT were independent risk factors for DFS and OS in high-grade STS patients treated with PORT. The mitotic rate, independent of tumor morphology, showed its potential as a prognostic biomarker for pathologic evaluation in patients treated with PORT.