Omentin reduces venous neointimal hyperplasia in arteriovenous fistula through hypoxia-inducible factor-1 alpha inhibition.

Arteriovenous fistula (AVF) failure often involves venous neointimal hyperplasia (VNH) driven by elevated hypoxia-inducible factor-1 alpha (HIF-1α) in the venous wall. Omentin, known for its anti-inflammatory and anti-hyperplasia properties, has an uncertain role in early AVF failure. This study investigates omentin's impact on VNH using a chronic renal failure (CRF) rabbit model. The CRF rabbit model of AVF received omentin-expressing adenoviral vector or control ß-gal vector to assess omentin's effects on VNH. Human vascular smooth muscle cells (HVSMCs), stimulated with tumor necrosis factor-α (TNF-α), were exposed to recombinant human omentin (Rh-OMT) to study its influence on cell proliferation and migration. The AMP-activated protein kinase (AMPK) inhibitor compound C and the mammalian target of rapamycin (mTOR) activator MHY1485 were employed to explore omentin's mechanisms in VNH reduction through HIF-1α inhibition. Omentin treatment reduced VNH in CRF rabbits, concomitant with HIF-1α down-regulation and the suppression of downstream factors, including vascular endothelial growth factor and matrix metalloproteinases. Rh-OMT inhibited TNF-α-induced HVSMC proliferation and migration by modulating both cell cycle and cell adhesion proteins. Additionally, omentin reduced HIF-1α expression through the AMPK/mTOR pathway activation. Notably, the blockade of AMPK/mTOR signaling reversed omentin-mediated inhibition of VNH, cell proliferation, and migration, both in vivo and in vitro. In conclusion, omentin mitigates VNH post-AVF creation by restraining HIF-1α via AMPK/mTOR signaling. Strategies boosting circulating omentin levels may offer promise in averting AVF failure.

The ACE2 expression of maternal-fetal interface and fetal organs indicates potential risk of vertical transmission of SARS-COV-2

Recent studies have demonstrated that SARS-CoV-2 cell entry depends on both ACE2 and TMPRSS2 genes (DOI: 10.1016/j.cell.2020.02.052), but our current work only focus on ACE2, which is insufficient to support the conclusion of this paper. So the authors have withdrawn their manuscript whilst they perform additional experiments and analysis to test some of their conclusions further. Therefore, the authors do not wish this work to be cited as reference for the project.

Standardized training of orthopedics residents in China and the United States: experience from the University of Maryland Shock Trauma / 中华医学教育探索杂志

By analyzing the training of resident doctors in the University of Maryland Shock Trauma, this paper compared the similarities and differences of standardized resident training between China and the United States in policy, training base, selection of teaching teachers, selection of training objects, assessment methods and financial subsidies to the students. It can be concluded that standardized resident training of orthopedics in the United States is more purposeful and systematic and pays more attention to the connection between knowledge and clinical practice, skills and operation, and the cultivation of the ability to deal with patients independently. The training of orthopedics residents in the United States began earlier and had more experience than China, which can be an example for the standardized training of orthopedics residents in China.

Preparation, performance and characterization of bioactive bone materials with plasticity / 中国组织工程研究

BACKGROUND:Foreign injectable sulphate calcium has good biocompatibility, injectability and in situimmobilization, moulding based on adaptation to the shape of bone defects, but the price is expensive. OBJECTIVE:To explore the optimal fabricating parameters of bone repair materials with α-calciumsulfate hemihydrates as the main component, and to study the performance and characterization METHODS:α-Calciumsulfate hemihydrates powder was mixed with sodium hyaluronate at liquid-solid-ratios of 0.2, 0.25, 0.3, 0.35, 0.4 mL/g using vapor-heat method to prepare injectable bone materials. Performance, setting time and compressive strength of the injectable bone was detected. The best liquid-solid-ratio was 0.3 mL/g.α-Calcium sulfate hemihydrates powder was mixed with calcium sulfate dihydrate powder (1%, 2%, 3% mass fractionas) to fabricate injectable bone materials. Performance, setting time and compressive strength of the injectable bone was also detected; meanwhile, the biosafety of the injectable bone was determined. Theinjectable bone material that was made at the liquid-solid-ratio of 0.3 mL/g and by 2% calcium sulfate dihydrate was implanted into Ba-ma swine models of thoracic bone defects. At the time points of 8, 16 and 24 weeks after implantation, histological observation was done. RESULTS AND CONCLUSION: The injectable bone material was made at the liquid-solid-ratio of 0.3 mL/g and by 2% calcium sulfate dihydrate. The initial and final setting time was 4.0-5.0 minutes and 8.0-9.0 minutes, respectively. The compressive strength of the injectable bone reached (8.93±0.23) MPa. These findings indicate that the injectable boen material has good performance, initial setting time and compressive strength meeting the requirements of clinical application and good biosafety. Animal experiments show that the injectable bone can provide space for new bone in creeping substitution way by auto-degradation, with osteogenic activity.

Comparative study of root canal morphology of mandibular first premolar by micro-CT and radio visio graphy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the consistency of root canal configuration types of mandibular first premolar by using micro-CT and radio visio graphy (RVG).</p><p><b>METHODS</b>One hundred extracted mandibular first premolars with complete dental root and apex which received no endodontic treatment were randomly selected. Each tooth was radiographed with RVG through a buccolingual and mesiodistal direction, and then scanned with micro-CT and reconstructed. The classifications of the root canal types according to Vertucci's type with the two methods were compared.</p><p><b>RESULTS</b>The canal patterns were classified as type I (67%), type III (3%), type V (18%), type VII (2%), additional type (10%) with micro-CT and canal patterns as type I (71%), type III (2%), type V (23%), type VII (1%), additional type (3%) with RVG. 63% of teeth showed one canal in both micro-CT and RVG. Only 25% of teeth were diagnosed as complex canal by the same canal type in both micro-CT and RVG. The Kappa value between micro-CT and RVG was 0.541 which suggested that the two kinds of methods had intermediate consistency. 82.8% of the premolars with root groove had two or more than two canals.</p><p><b>CONCLUSION</b>Although RVG can basically reflect the root canal system type of the mandibular first premolars in vitro, it offers poor accuracy images to complex root canals. Micro-CT three-dimensional images could clearly and precisely display the root canal system morphology of the mandibular first pre-molars in vitro.</p>