Mg-6Zn alloys promote the healing of intestinal anastomosis via TGF-ß/Smad signaling pathway in regulation of collagen metabolism as compared with titanium alloys.

There is a great clinical need for biodegradable materials. This study aimed to investigate the effects of Mg-6Zn and titanium alloy stapler nails on intestinal anastomosis healing mediated via the TGF-ß/Smad signaling pathway, as reflected in collagen metabolism in rabbits. Side-to-side ileo-ileostomy was performed with linear stapler loaded with the two nails. The results showed that no obvious postoperative complications such as abdominal infection and anastomotic leakage were observed. General observation and scanning electron microscope showed that Mg-6Zn alloy nails remained intact in the first week, degraded significantly in the second week, and were little left in the third week, while the titanium alloy nails showed intact substrate throughout the experimental period. Immunohistochemical analysis showed that the expression of TGF-ß1 in Mg-6Zn alloy group was higher than that in titanium alloy group after 1 week, but it increased slowly, arrived at a lower level in the third week. Collagen I showed an increased expression in Mg-6Zn alloy group, but decreased with time in titanium alloy group. An enhanced expression of collagen III in Mg-6Zn alloy group in the first week but much lower in the third week as compared to the titanium alloy group. The expression of smad2 in Mg-6Zn alloy group maintained a steady level, while in titanium alloy group it showed a general upward trend. The expression of smad3 in both groups held steady after 2 weeks, then in the third week, it showed a strong uptrend in Mg-6Zn alloy group, while decreased immediately in titanium alloy group. Our findings suggest that Mg-6Zn alloy nails degraded significantly within 3 weeks and could provide stability of intestinal anastomosis in the reconstruction of intestinal tract. TGF-ß/Smad signaling pathway may play a role in regulation of baseline collagen synthesis throughout the process.

Hybrid zeolite-based ion-exchange and sulfur oxidizing denitrification for advanced slaughterhouse wastewater treatment.

The discharge of slaughterhouse wastewater (SWW) is increasing and its wastewater has to be treated thoroughly to avoid the eutrophication. The hybrid zeolite-based ion-exchange and sulfur autotrophic denitrification (IX-AD) process was developed to advanced treat SWW after traditional secondary biological process. Compared with traditional sulfur oxidizing denitrification (SOD), this study found that IX-AD column showed: (1) stronger ability to resist NO3- pollution load, (2) lower SO42- productivity, and (3) higher microbial diversity and richness. Liaoning zeolites addition guaranteed not only the standard discharge of NH4+-N, but also the denitrification performance and effluent TN. Especially, when the ahead secondary biological treatment process run at the ultra-high load, NO3--N removal efficiency for IX-AD column was still ~100%, whereas only 64.2% for control SOD column. The corresponding average effluent TN concentrations for IX-AD and SOD columns were 5.89 and 65.55 mg/L, respectively. Therefore, IX-AD is a promising technology for advanced SWW treatment and should be widely researched and popularized.

The development and structure of the mesentery.

The position of abdominal organs, and mechanisms by which these are centrally connected, are currently described in peritoneal terms. As part of the peritoneal model of abdominal anatomy, there are multiple mesenteries. Recent findings point to an alternative model in which digestive organs are connected to a single mesentery. Given that direct evidence of this is currently lacking, we investigated the development and shape of the entire mesentery. Here we confirm that, within the abdomen, there is one mesentery in which all abdominal digestive organs develop and remain connected to. We show that all abdominopelvic organs are organised into two, discrete anatomical domains, the mesenteric and non-mesenteric domain. A similar organisation occurs across a range of animal species. The findings clarify the anatomical foundation of the abdomen; at the foundation level, the abdomen comprises a visceral (i.e. mesenteric) and somatic (i.e. musculoskeletal) frame. The organisation at that level is a fundamental order that explains the positional anatomy of all abdominopelvic organs, vasculature and peritoneum. Collectively, the findings provide a novel start point from which to systemically characterise the abdomen and its contents.

A novel lean alloy of biodegradable Mg-2Zn with nanograins.

Lean alloy (low alloyed) is beneficial for long-term sustainable development of metal materials. Creating a nanocrystalline microstructure is a desirable approach to improve biodegradability and mechanical properties of lean biomedical Mg alloy, but it is nearly impossible to realize. In the present study, the bulk nanocrystalline Mg alloy (average grain size: ~70 nm) was successfully obtained by hot rolling process of a lean Mg-2wt.%Zn (Z2) alloy and both high strength ((223 MPa (YS) and 260 MPa (UTS)) and good corrosion resistance (corrosion rate in vivo: 0.2 mm/year) could be achieved. The microstructure evolution during the rolling process was analyzed and discussed. Several factors including large strain, fine grains, strong basal texture, high temperature and Zn segregation conjointly provided the possibility for the activation of pyramidal slip to produce nanocrystals. This finding could provide a new development direction and field of application for lean biomedical Mg alloys.

Corrigendum to "Neuroprotective effect of Sanqi Tongshuan Tablets on sequelae post-stroke in rats" [Chinese Herbal Medicines 11 (2019) 45-51].

[This corrects the article DOI: 10.1016/j.chmed.2018.12.002.].

High-purity magnesium pin enhances bone consolidation in distraction osteogenesis via regulating Ptch protein activating Hedgehog-alternative Wnt signaling.

Magnesium alloys are promising biomaterials for orthopedic implants because of their degradability, osteogenic effects, and biocompatibility. Magnesium has been proven to promote distraction osteogenesis. However, its mechanism of promoting distraction osteogenesis is not thoroughly studied. In this work, a high-purity magnesium pin developed and applied in rat femur distraction osteogenesis. Mechanical test, radiological and histological analysis suggested that high-purity magnesium pin can promote distraction osteogenesis and shorten the consolidation time. Further RNA sequencing investigation found that alternative Wnt signaling was activated. In further bioinformatics analysis, it was found that the Hedgehog pathway is the upstream signaling pathway of the alternative Wnt pathway. We found that Ptch protein is a potential target of magnesium and verified by molecular dynamics that magnesium ions can bind to Ptch protein. In conclusion, HP Mg implants have the potential to enhance bone consolidation in the DO application, and this process might be via regulating Ptch protein activating Hedgehog-alternative Wnt signaling.

Consensus recommendations of three-dimensional visualization for diagnosis and management of liver diseases.

Three-dimensional (3D) visualization involves feature extraction and 3D reconstruction of CT images using a computer processing technology. It is a tool for displaying, describing, and interpreting 3D anatomy and morphological features of organs, thus providing intuitive, stereoscopic, and accurate methods for clinical decision-making. It has played an increasingly significant role in the diagnosis and management of liver diseases. Over the last decade, it has been proven safe and effective to use 3D simulation software for pre-hepatectomy assessment, virtual hepatectomy, and measurement of liver volumes in blood flow areas of the portal vein; meanwhile, the use of 3D models in combination with hydrodynamic analysis has become a novel non-invasive method for diagnosis and detection of portal hypertension. We herein describe the progress of research on 3D visualization, its workflow, current situation, challenges, opportunities, and its capacity to improve clinical decision-making, emphasizing its utility for patients with liver diseases. Current advances in modern imaging technologies have promised a further increase in diagnostic efficacy of liver diseases. For example, complex internal anatomy of the liver and detailed morphological features of liver lesions can be reflected from CT-based 3D models. A meta-analysis reported that the application of 3D visualization technology in the diagnosis and management of primary hepatocellular carcinoma has significant or extremely significant differences over the control group in terms of intraoperative blood loss, postoperative complications, recovery of postoperative liver function, operation time, hospitalization time, and tumor recurrence on short-term follow-up. However, the acquisition of high-quality CT images and the use of these images for 3D visualization processing lack a unified standard, quality control system, and homogeneity, which might hinder the evaluation of application efficacy in different clinical centers, causing enormous inconvenience to clinical practice and scientific research. Therefore, rigorous operating guidelines and quality control systems need to be established for 3D visualization of liver to develop it to become a mature technology. Herein, we provide recommendations for the research on diagnosis and management of 3D visualization in liver diseases to meet this urgent need in this research field.

High-purity magnesium pin enhances bone consolidation in distraction osteogenesis model through activation of the VHL/HIF-1α/VEGF signaling.

Distraction osteogenesis has widespread clinical use in the treatment of large bone defects. Nonetheless, the prolonged consolidation period carries the risk of complications. Magnesium-based materials have been shown to promote bone regeneration in fracture healing both in vitro and in vivo. Here, we investigated whether high-purity magnesium could enhance bone formation in distraction osteogenesis. High-purity magnesium pins were placed into the medullary cavity in the rat distraction osteogenesis model. Results showed that the bone volume/total tissue volume, bone mineral density, and mechanical properties of new callus were significantly higher in the high-purity magnesium group compared to stainless steel and control group (p < 0.01). Histological analyses confirmed improved bone consolidation and vascularization in high-purity magnesium group. Further, polymerase chain reaction-array investigation, Western blot, and immunohistochemical results found that vascular endothelial growth factor and hypoxia inducible factor-1α were highly expressed in the high-purity magnesium group, while Von Hippel-Lindau protein was the opposite (p < 0.01). In conclusion, high-purity magnesium implants have the potential to enhance angiogenesis and bone consolidation in the distraction osteogenesis application, and this process might be via the regulation of Von Hippel-Lindau/hypoxia inducible factor-1α/vascular endothelial growth factor signaling.

Microstructure controls the corrosion behavior of a lean biodegradable Mg-2Zn alloy.

Microstructural design was a long-term sustainable development method to improve the biodegradability and mechanical properties of low alloyed biomedical Mg alloys. In this study, the microstructural features (including grain size, deformation twin, deformed grains, sub-grains, and recrystallized grains) of the MZ2 ((Mg-2Zn (wt%)) alloy were controlled by different single-passed rolling reductions at high temperature. Besides the effect of grain size, we found that deformation twins and deformed grains influenced corrosion performance. Grain refinement with uniform distribution, meanwhile reducing the content of deformation twins, deformed grains, and sub-grains, was a practical method to improve both corrosion resistance and mechanical properties of MZ2 alloy. This finding proposed a better understanding of the development of lean biomedical Mg alloys with superior mechanical properties and favorable corrosion resistance. STATEMENT OF SIGNIFICANCE: Current research and development of biomedical Mg focused on alloying methods. The lean biodegradable Mg, which reduced the materials' compositional complexity, was the benefit of development for long-term sustainability. Here, our work revealed the relationship between microstructural features and corrosion resistance of a lean Mg-2Zn alloy during the different single-passed rolling processes. We found that recrystallized fine grains with partially ultra-fine grains could improve both strength and corrosion resistance. This study could give a new understanding of the development of lean biodegradable Mg alloys by using microstructural design to improve the overall performance of biomedical applications.

Biodegradable Mg Implants Suppress the Growth of Ovarian Tumor.

The common treatment of epithelial ovarian cancer is aggressive surgery followed by platinum-based cytotoxic chemotherapy. However, residual tumor cells are resistant to chemotherapeutic drugs during postoperative recurrence. The treatment of ovarian cancer requires breakthroughs and advances. In recent years, magnesium alloy has been widely developed as a new biodegradable material because of its great potential in the field of medical devices. From the degradation products of magnesium, biodegradable magnesium implants have great potential in antitumor. According to the disease characteristics of ovarian cancer, we choose it to study the antitumor characteristics of biodegradable magnesium. We tested the anti-ovarian tumor properties of Mg through both in vivo and in vitro experiments. According to the optical in vivo imaging and relative tumor volume statistics of mice, high-purity Mg wires significantly inhibited the growth of SKOV3 cells in vivo. We find that the degradation products of Mg, Mg2+, and H2 significantly inhibit the growth of SKOV3 cells and promote their apoptosis. Our study suggests a good promise for the treatment of ovarian cancer.

Applied anatomy and three-dimensional visualization of the tendon-bone junctions of the knee joint posterolateral complex.

BACKGROUND: To conduct an anatomical study of the fibular collateral ligament (FCL), popliteus tendon (PT), biceps femoris tendon (BT) and popliteofibular ligament (PFL) of the knee joint posterolateral complex (PLC) at the femoral and fibular tendon-bone junctions based on the Chinese Visible Human (CVH) and American Visual Human Project (VHP) datasets and to determine their morphology, contact area, center points and mutual distances with the aim of providing assistance for surgical tunneling scheme. METHODS: Ten knee joint datasets were selected for segmentation and three-dimensional digital reconstruction. Histological sections images were used to establish criteria for the segmentation. The PLC tendon-junctions were observed and studied. RESULTS: The FCL and PT had constant attachment to the femur, and the FCL, BT and PFL had constant attachment to the fibula. The tendon-bone junctions of each PLC structure did not have a uniform morphology or the same contact area, but the location of the central point of the tendon-bone junction was similar and regularly attached. All measurements were smaller in the CVH dataset than VHP dataset. At the femoral tendon-bone junction, the average distance between the center points of the FCL and PT was 8.84 ±â€¯1.62 mm (7.73 ±â€¯1.44 mm in the CVH datasets and 9.50 ±â€¯1.38 mm in the VHP datasets). CONCLUSIONS: The authors propose a surgical tunneling scheme for femoral single-tunnel reconstruction in Chinese PLC reconstruction patients. The research data provide a theoretical basis and guidance for clinicians who need to design and select PLC surgical tunneling schemes.

Interactive three-dimensional teaching models of the female and male pelvic floor.

Controversies regarding structure and function of the pelvic floor persist because of its poor accessibility and complex anatomical architecture. Most data are based on dissection. This "surgical" approach requires profound prior knowledge, because applying the scalpel precludes a "second look." The "sectional" approach does not entail these limitations, but requires segmentation of structures and three-dimensional reconstruction. This approach has produced several "Visible Human Projects." We dealt with limited spatial resolution and difficult-to-segment structures by proceeding from clear-cut to more fuzzy boundaries and comparing segmentation between investigators. We observed that the bicipital levator ani muscle consisted of pubovisceral and puborectal portions; that the pubovisceral muscle formed, together with rectococcygeal and rectoperineal muscles, a rectal diaphragm; that the external anal sphincter consisted of its subcutaneous portion and the puborectal muscle only; that the striated urethral sphincter had three parts, of which the middle (urethral compressor) was best developed in females and the circular lower ("membranous") best in males; that the rectourethral muscle, an anterior extension of the rectal longitudinal smooth muscle, developed a fibrous node in its center (perineal body); that the perineal body was much better developed in females than males, so that the rectourethral subdivision into posterior rectoperineal and anterior deep perineal muscles was more obvious in females; that the superficial transverse perineal muscle attached to the fibrous septa of the ischioanal fat; and that the uterosacral ligaments and mesorectal fascia colocalized. To facilitate comprehension of the modified topography we provide interactive 3D-PDFs that are freely available for teaching purposes. Clin. Anat. 33:275-285, 2020. © 2019 Wiley Periodicals, Inc.

Local intragranular misorientation accelerates corrosion in biodegradable Mg.

Mg-based implants are used in biomedical applications predominantly because of their degradable property. In this paper, the effect of local misorientations (intragranular misorientation) on the corrosion behavior of high-purity Mg (HPM) was systematically investigated according to microstructure characterization and corrosion measurements. The results showed that local misorientation introduced into grains by deformation could result in corrosion around the grain boundary (GB), which ultimately reduces the corrosion resistance of HPM. After removing the local misorientation by annealing, the corrosion around GB could be eliminated. This work is expected to inspire better control over the degradation behaviors of biomedical Mg through microstructure design to be used for various biomedical applications. STATEMENT OF SIGNIFICANCE: 1. Fine grains, fine grains with large local misorientation, and coarse grains could be obtained, respectively, in high-purity Mg by sequential hot rolling, compression deformation, and annealing treatments. 2. Large local misorientation introduced into grains could lead to corrosion around the grain boundary and ultimately reduce corrosion resistance. 3. In the absence of local misorientation, refining grain size could improve the corrosion resistance of Mg.

Crevice corrosion - A newly observed mechanism of degradation in biomedical magnesium.

Crevice-induced corrosion is not desirable to occur in metallic magnesium (Mg) during many industrial applications. However, orthopedic implants made of Mg alloys have been demonstrated to degrade faster between the joining surface of bone plates and screws after implantation, suggesting the crevice corrosion may occur in the physiological environment. In this paper, a resin device is designed to parallel high purity magnesium (HP-Mg) plates with closely spaced slits. After a standard corrosion test in the phosphate-buffered saline (PBS) solution, the paralleled HP-Mg samples embedded in the custom-made resin device corrode faster than those without the resin device. The corrosion morphology of Mg with the resin device exhibits features of crevice corrosion with many deep holes and river-like texture. Moreover, implantation of the bone plate and screws in vivo demonstrates similar corrosion morphology as that of the in vitro test, suggesting the occurrence of crevice-enhanced corrosion in the bone-bone plate interface, as well as the contact area between the bone plate and the screws. STATEMENT OF SIGNIFICANCE: Understanding the corrosion behavior of Mg and Mg alloys after implantation is one of the main challenges for developing desirable biodegradable Mg alloys or effective methods to adjust the corrosion rate of Mg-based implants. In this paper, we attempted to understand the corrosion behaviors of HP-Mg at the joining surface between HP-Mg plates or HP-Mg screws and bone tissues after implantation. We designed an in vitro setup to mimic the crevice environment of the in vivo joining surface and found that the crevices existing on the HP-Mg would significantly accelerate the corrosion rate and change the corrosion morphology of HP-Mg plates. The in vivo implantation also showed similar corrosion morphology caused by crevice corrosion, which appeared at the joining surface between HP-Mg plates or HP-Mg screws and bone tissues. Then, we proposed a new corrosion mechanism of Mg-based alloys inside the crevice. The findings of this study can help us broaden our cognition on the corrosion behavior of Mg and Mg alloy-based orthopedic implants.

Application of three-dimensional reconstruction and printing as an elective course for undergraduate medical students: an exploratory trial.

BACKGROUND: Medical three-dimensional (3D) digital reconstruction and printing have become common tools in medicine, but few undergraduate medical students understand its whole process and teaching and clinical application. Therefore, we designed an elective course of 3D reconstruction and printing for students and studied its significance and practicability. METHODS: Thirty undergraduate medical students in their second-year of study volunteered to participate in the course. The course started with three lessons on the theory of 3D digital reconstruction and printing in medicine. The students were then randomly divided into ten groups. Each group randomly selected its own original data set, which could contain a series of 2D images including sectional anatomical images, histological images, CT and MRI. Amira software was used to segment the structures of interest, to 3D reconstruct them and to smooth and simplify the models. These models were 3D printed and post-processed. Finally, the 3D digital and printed models were scored, and the students produced brief reports of their work and knowledge acquisition and filled out an anonymous questionnaire about their study perceptions. RESULTS: All the students finished this course. The average score of the 30 students was 83.1 ± 2.7. This course stimulated the students' learning interest and satisfied them. It was helpful for undergraduate students to understand anatomical structures and their spatial relationship more deeply. Students understood the whole process of 3D reconstruction and printing and its teaching and clinical applications through this course. CONCLUSION: It is significant and necessary to develop this course for undergraduate medical students.

Translational status of biomedical Mg devices in China.

Magnesium (Mg) and its alloys as temporary medical implants with biodegradable and properly mechanical properties have been investigated for a long time. There are already three kinds of biodegradable Mg implants which are approved by Conformite Europeene (CE) or Korea Food and Drug Administration (KFDA), but not China Food and Drug Administration (CFDA, now it is National Medical Products Administration, NMPA). As we know, Chinese researchers, surgeons, and entrepreneurs have tried a lot to research and develop biodegradable Mg implants which might become other new approved implants for clinical applications. So in this review, we present the representative Mg implants of three categories, orthopedic implants, surgical implants, and intervention implants and provide an overview of current achievement in China from academic publications and Chinese patents. We would like to provide a systematic way to translate Mg and its alloy implants from experiment designs to clinical products.

Modeling and simulation of an anatomy teaching system.

Specimen observation and dissection have been regarded as the best approach to teach anatomy, but due to the severe lack of anatomical specimens in recent years, the quality of anatomy teaching has been seriously affected. In order to disseminate anatomical knowledge effectively under such circumstances, this study discusses three key factors (modeling, perception, and interaction) involved in constructing virtual anatomy teaching systems in detail. To ensure the authenticity, integrity, and accuracy of modeling, detailed three-dimensional (3D) digital anatomical models are constructed using multi-scale data, such as the Chinese Visible Human dataset, clinical imaging data, tissue sections, and other sources. The anatomical knowledge ontology is built according to the needs of the particular teaching purposes. Various kinds of anatomical knowledge and 3D digital anatomical models are organically combined to construct virtual anatomy teaching system by means of virtual reality equipment and technology. The perception of knowledge is realized by the Yi Chuang Digital Human Anatomy Teaching System that we have created. The virtual interaction mode, which is similar to actual anatomical specimen observation and dissection, can enhance the transmissibility of anatomical knowledge. This virtual anatomy teaching system captures the three key factors. It can provide realistic and reusable teaching resources, expand the new medical education model, and effectively improve the quality of anatomy teaching.

Sectional Anatomy and Three-Dimensional Visualization of the Posterolateral Complex of the Knee Joint Based on Undeformed High-Resolution Sectional Anatomical Images.

The anatomy of the posterolateral complex (PLC) of the knee is usually studied by dissection and magnetic resonance (MR) imaging, which is still controversial. We aim to study it based on the images and an interactive 3D-PDF from the Chinese Visible Human (CVH) datasets. CVH datasets (six transverse and one coronal) of the PLC and its adjacent structures were segmented and three-dimensionally reconstructed. Histological sections images were used to establish criteria for the segmentation. MR images were studied in comparison with CVH images. The PLC was mainly composed of the fibular collateral ligament (FCL), popliteofibular ligament (PFL), arcuate popliteal ligament (APL), popliteus tendon (PT), fabellofibular ligament (FFL) and biceps femoris tendon (BT). These structures had origins or insertions located close to each other and collectively maintained the stability of the PLC. The origins of the PT and the FCL were located on the lateral condyle of the femur. The APL was "Y" shaped and had a 100% occurrence in our study. Its lateral and medial heads originated, respectively, from the posterolateral part and medial-inferior part of fibrous capsule close to the lateral femoral condyle. The FCL, BT, main trunk of the APL, PFL and FFL had adjacent insertions on the posterolateral fibular head. CVH high-resolution sectional anatomical images and a 3D-pdf provided detailed morphological data for the PLC, and improved the identification and diagnostic accuracy for the PLC in MRI. We speculate that APL has a strong biological and mechanistic significance in the PLC. Anat Rec, 301:1764-1773, 2018. © 2018 Wiley Periodicals, Inc.

Multi-object Model-Based Multi-atlas Segmentation Constrained Grid Cut for Automatic Segmentation of Lumbar Vertebrae from CT Images.

In this chapter, we present a multi-object model-based multi-atlas segmentation constrained grid cut method for automatic segmentation of lumbar vertebrae from a given lumbar spinal CT image. More specifically, our automatic lumbar vertebrae segmentation method consists of two steps: affine atlas-target registration-based label fusion and bone-sheetness assisted multi-label grid cut which has the inherent advantage of automatic separation of the five lumbar vertebrae from each other. We evaluate our method on 21 clinical lumbar spinal CT images with the associated manual segmentation and conduct a leave-one-out study. Our method achieved an average Dice coefficient of 93.9 ± 1.0% and an average symmetric surface distance of 0.41 ± 0.08 mm.