Curculigoside Protects against Titanium Particle-Induced Osteolysis through the Enhancement of Osteoblast Differentiation and Reduction of Osteoclast Formation.

Wear particle-induced periprosthetic osteolysis is mainly responsible for joint replacement failure and revision surgery. Curculigoside is reported to have bone-protective potential, but whether curculigoside attenuates wear particle-induced osteolysis remains unclear. In this study, titanium particles (Ti) were used to stimulate osteoblastic MC3T3-E1 cells in the presence or absence of curculigoside, to determine their effect on osteoblast differentiation. Rat osteoclastic bone marrow stromal cells (BMSCs) were cocultured with Ti in the presence or absence of curculigoside, to evaluate its effect on osteoclast formation in vitro. Ti was also used to stimulate mouse calvaria to induce an osteolysis model, and curculigoside was administrated to evaluate its effect in the osteolysis model by micro-CT imaging and histopathological analyses. As the results indicated, in MC3T3-E1 cells, curculigoside treatment attenuated the Ti-induced inhibition on cell differentiation and apoptosis, increased alkaline phosphatase activity (ALP) and cell mineralization, and inhibited TNF-α, IL-1ß, and IL-6 production and ROS generation. In BMSCs, curculigoside treatment suppressed the Ti-induced cell formation and suppressed the TNF-α, IL-1ß, and IL-6 production and F-actin ring formation. In vivo, curculigoside attenuated Ti-induced bone loss and histological damage in murine calvaria. Curculigoside treatment also reversed the RANK/RANKL/OPG and NF-κB signaling pathways, by suppressing the RANKL and NF-κB expression, while activating the OPG expression. Our study demonstrated that curculigoside treatment was able to attenuate wear particle-induced periprosthetic osteolysis in in vivo and in vitro experiments, promoted osteoblastic MC3T3-E1 cell differentiation, and inhibited osteoclast BMSC formation. It suggests that curculigoside may be a potential pharmaceutical agent for wear particle-stimulated osteolysis therapy.

Judicious use of low-dosage corticosteroids for non-severe COVID-19: A case report.

Inflammation-mediated lung injury in severe cases of infection with SARS-CoV-2, the aetiological agent of Coronavirus disease 2019 (COVID-19), can lead to respiratory failure and death, and therapies that block or ameliorate lung injury-associated inflammatory "cytokine storms" and progression to acute respiratory distress syndrome (ARDS) are urgently needed. Therapeutic use of corticosteroids for this purpose has been controversial because of conflicting reports on their efficacy and immunosuppressive behaviour. The WHO has strongly recommended treating critical COVID-19 patients with systemic corticosteroid therapy, but recommends against corticosteroid therapy in non-severe COVID-19 disease because of a lack of strong evidence on its efficacy. This retrospective case report describing the successful treatment of a non-severe COVID-19 case in Changchun, China, by judicious administration of corticosteroids using a personalized therapeutic approach was recorded to strengthen the evidence base showing how corticosteroid use in non-severe COVID-19 cases can be safe and efficacious. Alongside supportive care and lopinavir/ritonavir antiviral drugs, a low dosage of methylprednisolone was administered over a short period to attenuate lung inflammation. Regular chest CT scans guided dosage reduction in response to lesion absorption and improved lung condition. Judicious use of corticosteroids safely attenuated disease progression and facilitated rapid and complete recovery.

Compound word frequency modifies the effect of character frequency in reading Chinese.

In two eye-tracking studies, reading of two-character Chinese compound words was examined. First and second character frequency were orthogonally manipulated to examine the extent to which Chinese compound words are processed via the component characters. In Experiment 1, first and second character frequency were manipulated for frequent compound words, whereas in Experiment 2 it was done for infrequent compound words. Fixation time and skipping probability for the first and second character were affected by its frequency in neither experiment, nor in their pooled analysis. Yet, in Experiment 2 fixations on the second character were longer when a high-frequency character was presented as the first character compared with when a low-frequency character was presented as the first character. This reversed character frequency effect reflects a morphological family size effect and is explained by the constraint hypothesis, according to which fixation time on the second component of two-component compound words is shorter when its identity is constrained by the first component. It is concluded that frequent Chinese compound words are processed holistically, whereas with infrequent compound words there is some room for the characters to play a role in the identification process.

Structure From Motion on XSlit Cameras.

We present a structure-from-motion (SfM) framework based on a special type of multi-perspective camera called the cross-slit or XSlit camera. Traditional perspective camera based SfM suffers from the scale ambiguity which is inherent to the pinhole camera geometry. In contrast, an XSlit camera captures rays passing through two oblique lines in 3D space and we show such ray geometry directly resolves the scale ambiguity when employed for SfM. To accommodate the XSlit cameras, we develop tailored feature matching, camera pose estimation, triangulation, and bundle adjustment techniques. Specifically, we devise a SIFT feature variant using non-uniform Gaussian kernels to handle the distortions in XSlit images for reliable feature matching. Moreover, we demonstrate that the XSlit camera exhibits ambiguities in pose estimation process which can not be handled by existing work. Consequently, we propose a 14 point algorithm to properly handle the XSlit degeneracy and estimate the relative pose between XSlit cameras from feature correspondences. We further exploit the unique depth-dependent aspect ratio (DDAR) property to improve the bundle adjustment for the XSlit camera. Synthetic and real experiments demonstrate that the proposed XSlit SfM can conduct reliable and high fidelity 3D reconstruction at an absolute scale.

Refocusable Gigapixel Panoramas for Immersive VR Experiences.

There have been significant advances in capturing gigapixel panoramas (GPP). However, solutions for viewing GPPs on head-mounted displays (HMDs) are lagging: an immersive experience requires ultra-fast rendering while directly loading a GPP onto the GPU is infeasible due to limited texture memory capacity. In this paper, we present a novel out-of-core rendering technique that supports not only classic panning, tilting, and zooming but also dynamic refocusing for viewing a GPP on HMD. Inspired by the network package transmission mechanisms in distributed visualization, our approach employs hierarchical image tiling and on-demand data updates across the main and the GPU memory. We further present a multi-resolution rendering scheme and a refocused light field rendering technique based on RGBD GPPs with minimal memory overhead. Comprehensive experiments demonstrate that our technique is highly efficient and reliable, able to achieve ultra-high frame rates ( fps) even on low-end GPUs. With an embedded gaze tracker, our technique enables immersive panorama viewing experiences with unprecedented resolutions, field-of-view, and focus variations while maintaining smooth spatial, angular, and focal transitions.

[Progress on prevention and treatment of heterotopic ossification].

Heterotopic ossification is the formation of pathological bone in non-skeletal tissues (including muscles, tendons or other soft tissues), and the pathogenesis is not completely clear. It is often caused by musculoskeletal trauma, postoperative bone and joint surgery, or damage of the nervous system, the clinical manifestations are joint swelling, pain, and movement disorders, which often occur around the hips, knees, and elbows. At present, the prevention of heterotopic ossification mainly includes drugs, radiotherapy, molecular biological mechanism intervention, and Chinese medicine-related measures. Among them, drugs and radiotherapy are more effective methods to prevent heterotopic ossification. The intervention of molecular biology mechanism to prevent heterotopic ossification has become a new research direction and focus of attention inrecent years, and is basically at the experimental research stage. The treatment of heterotopic ossification includes various methods such as drugs, physical therapy, and surgery. Among them, surgery is recognized as the most effective treatment, however there are still some controversies and disagreements about the choice of operation time and surgical methods.

Abdominal obesity and colorectal cancer risk: systematic review and meta-analysis of prospective studies.

The association between abdominal obesity (as measured by waist circumference (WC) and waist-to-hip ratio (WHR)) and colorectal cancer (CRC) has not been fully quantified, and the magnitude of CRC risk associated with abdominal obesity is still unclear. A meta-analysis of prospective studies was performed to elucidate the CRC risk associated with abdominal obesity. Pubmed and Embase were searched for studies assessing the association between abdominal obesity and CRC risk. Relative risks (RRs) with 95% confidence intervals (95% CIs) were pooled using random-effects model of meta-analysis. Nineteen prospective cohort studies from eighteen publications were included in this meta-analysis. A total of 12,837 CRC cases were identified among 1,343,560 participants. Greater WC and WHR were significantly associated with increased risk of total colorectal cancer (WC: RR 1.42, 95% CI 1.30, 1.55; WHR: RR 1.39, 95% CI 1.25, 1.53), colon cancer (WC: RR 1.53, 95% CI 1.36, 1.72; WHR: 1.39, 95% CI 1.18, 1.63), and rectal cancer (WC: RR 1.20, 95% CI 1.03, 1.39; WHR: RR 1.22, 95% CI 1.05, 1.42). Subgroup analyses further identified the robustness of the association above. No obvious risk of publication bias was observed. In summary, abdominal obesity may play an important role in the development of CRC.

Local influence of high molecular polyethylene particles on heterotopic ossification.

We studied the effect of molecular polyethylene particles on local heterotopic ossification. A total of 36 healthy Sprague-Dawley rats were randomly divided into the control group (n=18) and the observation group (n=18). High molecular polyethylene particles were injected to rupture Achilles tendon position in the observation group, and normal saline was injected in the control group. X-ray examinations were conducted on Achilles tendon in the 4th, 8th and 12th week after operation. The incidence rate of heterotopic ossification was evaluated, and bone trabecula morphological structure was studied under optical microscope after hematoxylin and eosin staining. Bone morphogenetic protein 2 (BMP-2), transforming growth factor-ß (TGF-ß), interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), runt-related transcription factor 2 (Runx2) and matrix metalloproteinase-9 (MMP-9) expression levels were also measured. Our results showed that heterotopic ossification incidence in the observation group was significantly lower than that in the control group. Achilles tendon structure in the control group increased in volume, and its texture was harder and cartilage-like. In the observation group, trabecular bone volume, thickness and quantity were more than those observed in the control group. BMP-2, TGF-ß, IL-1, TNF-α, Runx2 and MMP-9 levels in the observation group were significantly lower than those in the control group. We concluded that, high molecular polyethylene particles had a significant inhibiting effect on local heterotopic ossification.

Mechanisms underlying the antiapoptotic and anti-inflammatory effects of monotropein in hydrogen peroxide-treated osteoblasts.

Monotropein, the primary iridoid glycoside isolated from Morindacitrifolia, has been previously reported to possess potent antioxidant and antiosteoporotic properties. However, there is no direct evidence correlating the antiosteoporotic effect of monotropein with its observed antioxidant capacity, and the molecular mechanisms involved in mediating these processes remain unclear. Therefore, the aim of the present study was to investigate the protective effects of monotropein against oxidative stress in osteoblasts and the mechanisms involved in mediating this process. Osteoblast viability was evaluated using the MTT assay. The mitochondrial membrane potential and reactive oxygen species were detected by flow cytometry analyses. Western blotting and enzyme­linked immunosorbent assays were performed to detect protein expression levels. A significant reduction in osteoblast viability was observed at 24 h following exposure to various concentrations (100­1,000 µM) of H2O2 compared with untreated osteoblasts. The cytotoxic effect of H2O2 was notably reversed when osteoblasts were pretreated with 1­10 µg/ml monotropein. Pretreatment with 1-10 µg/ml monotropein increased the mitochondrial membrane potential and reduced the generation of reactive oxygen species in osteoblasts following exposure to H2O2. In addition, the H2O2­induced increase in apoptotic markers (caspase-3 and caspase-9) and H2O2-induced reduction in sirtuin 1 levels were significantly reversed following pretreatment of cells with monotropein. Furthermore, monotropein significantly reduced H2O2­induced stimulation of NF­κB expression, in addition to the expression of a number of proinflammatory mediators. These results indicate that monotropein suppresses apoptosis and the inflammatory response in H2O2­induced osteoblasts through the activation of the mitochondrial apoptotic signaling pathway and inhibition of the NF­κB signaling pathway.

Curculigoside regulates proliferation, differentiation, and pro-inflammatory cytokines levels in dexamethasone-induced rat calvarial osteoblasts.

BACKGROUND: Curculigoside (CCG), one of the main bioactive phenolic compounds isolated from the rhizome of Curculigo orchioides Gaertn., is reported to prevent bone loss in ovariectomized rats. However, the underlying molecular mechanisms are largely unknown. Therefore, we investigated the effects of CCG on proliferation and differentiation of calvarial osteoblasts and discussed the related mechanisms. MATERIALS AND METHODS: Osteoblasts were incubated with dexamethasone (DEX) in the absence or presence of CCG concentrations for 24-72 h. Cell proliferation was evaluated by Cell Counting Kit-8 assay. Mitochondria membrane potential (MMP) and reactive oxygen species (ROS) were assessed by flow cytometry. We assessed the anti-inflammatory responses of CCG on DEX-induced osteoblasts by an enzyme-linked immunosorbent assay (ELISA). Relative protein expression of BMP-2, b-catenin, RANKL, OPG and RANK was measured using Western blotting. RESULTS: It was found that osteoblasts proliferation decreased significantly after treated with 1 µM of dexamethasone (DEX), compared with untreated osteoblasts and the cytotoxic effect of DEX was reversed remarkably when pretreatment with 25-100 µg/ml of CCG. Pretreatment with 25-100 µg/ml of CCG increased MMP level and decreased ROS production in osteoblasts induced by DEX. In addition, DEX-induced inhibition of differentiation markers such as alkaline phosphatase (ALP), OPG, BMP-2, ß-catenin, IGF-1 and M-CSF level, and promotion of differentiation markers such as RANKL and RANK was significantly reversed in the presence of CCG. CCG also reversed DEX-induced production of pro-inflammatory cytokines. CONCLUSIONS: These results provide new insights into the osteoblast-protective mechanisms of CCG through inducing proliferation and differentiation and reducing the inflammatory responses, indicating that CCG may be developed as an agent for the prevention and treatment of osteoporosis.