A Biomimetic Fibrous Composite Scaffold with Nanotopography-Regulated Mineralization for Bone Defect Repair.

The effective regeneration of large bone defects via bone tissue engineering is challenging due to the difficulty in creating an osteogenic microenvironment. Inspired by the fibrillar architecture of the natural extracellular matrix, we developed a nanoscale bioengineering strategy to produce bone fibril-like composite scaffolds with enhanced osteogenic capability. To activate the surface for biofunctionalization, self-adaptive ridge-like nanolamellae were constructed on poly(ε-caprolactone) (PCL) electrospinning scaffolds via surface-directed epitaxial crystallization. This unique nanotopography with a markedly increased specific surface area offered abundant nucleation sites for Ca2+ recruitment, leading to a 5-fold greater deposition weight of hydroxyapatite than that of the pristine PCL scaffold under stimulated physiological conditions. Bone marrow mesenchymal stem cells (BMSCs) cultured on bone fibril-like scaffolds exhibited enhanced adhesion, proliferation, and osteogenic differentiation in vitro. In a rat calvarial defect model, the bone fibril-like scaffold significantly accelerated bone regeneration, as evidenced by micro-CT, histological histological and immunofluorescence staining. This work provides the way for recapitulating the osteogenic microenvironment in tissue-engineered scaffolds for bone repair.

Diagnosis and Monitoring of Tunnel Lining Defects by Using Comprehensive Geophysical Prospecting and Fiber Bragg Grating Strain Sensor.

Tunnel excavation induces the stress redistribution of surrounding rock. In this excavation process, the elastic strain in the rock is quickly released. When the maximum stress on the tunnel lining exceeds the concrete's load-bearing capacity, it causes cracking of the lining. Comprehensive geophysical exploration methods, including seismic computerized tomography, the high-density electrical method, and the ultrasonic single-plane test, indicated the presence of incomplete distribution of broken rock along the tunnel axis. Based on the geophysical exploration results, a carbon-fiber-strengthened tunnel simulation model was established to analyze the mechanical characteristics of the structure and provide a theoretical basis for sensor deployment. Fiber Bragg grating (FBG) strain sensors were used to measure the stress and strain changes in the second lining concrete after carbon reinforcement. Meanwhile, one temperature sensor was installed in each section to enable temperature compensation. The monitoring results demonstrated that the stress-strain of the second lining fluctuated within a small range, and the lining did not show any crack expansion behavior, which indicated that carbon-fiber-reinforced polymer (CFRP) played an effective role in controlling the structural deformation. Therefore, the combined detection of physical exploration and FBG sensors for the structure provided an effective monitoring method for evaluating tunnel stability.

Effects of exposure to multiple metallic elements in the first trimester of pregnancy on the risk of preterm birth.

Exposure to certain heavy metals has been demonstrated to be associated with a higher risk of preterm birth (PTB). However, studies focused on the effects of other metal mixtures were limited. A nested case‒control study enrolling 94 PTB cases and 282 controls was conducted. Metallic elements were detected in maternal plasma collected in the first trimester using inductively coupled plasma‒mass spectrometry. The effect of maternal exposure on the risk of PTB was investigated using logistic regression, least absolute shrinkage and selection operator, restricted cubic spline (RCS), quantile g computation (QGC) and Bayesian kernel machine regression (BKMR). Vanadium (V) and arsenic (As) were positively associated with PTB risk in the logistic model, and V remains positively associated in the multi-exposure logistic model. QGC analysis determined V (69.42%) and nickel (Ni) (70.30%) as the maximum positive and negative contributors to the PTB risk, respectively. BKMR models further demonstrated a positive relationship between the exposure levels of the mixtures and PTB risk, and V was identified as the most important independent variable among the elements. RCS analysis showed an inverted U-shape effect of V and gestational age, and plasma V more than 2.18 µg/L was considered a risk factor for shortened gestation length. Exposure to metallic elements mixtures consisting of V, As, cobalt, Ni, chromium and manganese in the first trimester was associated with an increased risk of PTB, and V was considered the most important factor in the mixtures in promoting the incidence of PTB.

[New Advances in the Application of Bacterial Cellulose Composite Materials in the Field of Bone Tissue Engineering]. / ç»†èŒçº¤ç»´ç´ å¤åˆææ–™åœ¨éª¨ç»„ç»‡å·¥ç¨‹é¢†åŸŸçš„åº”ç”¨æ–°è¿›å±•.

Bacterial cellulose (BC) is a type of extracellular polymeric nanomaterial secreted by microorganisms over the course of their growth. It has gained significant attention in the field of bone tissue engineering due to its unique structure of three-dimensional fibrous network, excellent biocompatibility, biodegradability, and exceptional mechanical properties. Nevertheless, BC still has some weaknesses, including low osteogenic activity, a lack of antimicrobial properties, small pore size, issues with the degradation rate, and a mismatch in bone tissue regeneration, limiting its standalone use in the field of bone tissue engineering. Therefore, the modification of BC and the preparation of BC composite materials have become a recent research focus. Herein, we summarized the relationships between the production, modification, and bone repair applications of BC. We introduced the methods for the preparation and the modification of BC. Additionally, we elaborated on the new advances in the application of BC composite materials in the field of bone tissue engineering. We also highlighted the existing challenges and future prospects of BC composite materials.

Endophytic Penicillium oxalicum CX-1 prevented Phytophthora cactorum blight on Salvia miltiorrhiza and promoted plant growth.

AIM: The main purpose of this study was to study the preventive effect of Penicillium sp. CX-1 on Phytophthora cactorum causing Salvia miltiorrhiza blight and its positive effect on plant growth. METHODS AND RESULTS: The endophytic strain CX-1 was isolated from the medicinal plant Corydalis saxicola Bunting and identified as Penicillium oxalicum. The growth inhibitory capacity of CX-1 against Ph. cactorum was 74.4% in the strain co-culture test and 86.2% in filtrate-modified plates. In the pot experiment, the in vivo control of CX-1 against Ph. cactorum in S. miltiorrhiza was 36.0%, which was higher than that of an anti-Phytophthora fungicide (23.4%). In addition, CX-1 had a potent ability to solubilize phosphate and also showed the ability to produce the plant hormone indole-3-acetic acid (IAA) and siderophores, which increase the bioavailability of iron to plants. It was demonstrated through pot experiments that CX-1 could significantly promote plant growth. As determined by real-time quantitative PCR, the expression of some S. miltiorrhiza tanshinone-related biosynthesis genes was significantly upregulated following colonization by CX-1. CONCLUSION: Strain CX-1 could effectively inhibit Ph. cactorum, the causative agent of S. miltiorrhiza blight, and significantly promoted the growth of plants through several different routes.

Discovery of Novel 3,11-Bispeptide Ester Arenobufagin Derivatives with Potential in Vivo Antitumor Activity and Reduced Cardiotoxicity.

Arenobufagin, one of the bufadienolides isolated from traditional Chinese medicine Chan'su, exhibits potent antitumor activity. However, serious toxicity and small therapeutic window limits its drug development. In the present study, to our knowledge, novel 3,11-bispeptide ester arenobufagin derivatives have been firstly designed and synthesized on the base of our previous discovery of active 3-monopeptide ester derivative. The in vitro antiproliferative activity evaluation revealed that the moiety at C3 and C11 hydroxy had an important influence on cytotoxic activity and selectivity. Compound ZM350 notably inhibited tumor growth by 58.8 % at a dose 10 mg/kg in an A549 nude mice xenograft model. Therefore, compound ZM350 also presented a concentration-dependent apoptosis induction and low inhibitory effect against both hERG potassium channel and Cav1.2 calcium channel. Our study suggests that novel 3,11-bispeptide ester derivatives will be a potential benefit to further antitumor agent development of arenobufagin.

Long-form recording of infant body position in the home using wearable inertial sensors.

Long-form audio recordings have had a transformational effect on the study of infant language acquisition by using mobile, unobtrusive devices to gather full-day, real-time data that can be automatically scored. How can we produce similar data in service of measuring infants' everyday motor behaviors, such as body position? The aim of the current study was to validate long-form recordings of infant position (supine, prone, sitting, upright, held by caregiver) based on machine learning classification of data from inertial sensors worn on infants' ankles and thighs. Using over 100 h of video recordings synchronized with inertial sensor data from infants in their homes, we demonstrate that body position classifications are sufficiently accurate to measure infant behavior. Moreover, classification remained accurate when predicting behavior later in the session when infants and caregivers were unsupervised and went about their normal activities, showing that the method can handle the challenge of measuring unconstrained, natural activity. Next, we show that the inertial sensing method has convergent validity by replicating age differences in body position found using other methods with full-day data captured from inertial sensors. We end the paper with a discussion of the novel opportunities that long-form motor recordings afford for understanding infant learning and development.

[Protective mechanism of tetramethylpyrazine on cardiovascular system].

Tetramethylpyrazine is the main component of Ligusticum chuanxiong. Studies have found that tetramethylpyrazine has a good protective effect against cardiovascular diseases. In the heart, tetramethylpyrazine can reduce myocardial ischemia/reperfusion injury by inhibiting oxidative stress, regulating autophagy, and inhibiting cardiomyocyte apoptosis. Tetramethylpyrazine can also reduce the damage of cardiomyocytes caused by inflammation, relieve the fibrosis and hypertrophy of cardiomyocytes in infarcted myocardium, and inhibit the expansion of the cardiac cavity after myocardial infarction. In addition, tetramethylpyrazine also has a protective effect on the improvement of familial dilated cardiomyopathy. Besides, the mechanisms of tetramethylpyrazine on blood vessels are more abundant. It can inhibit endothelial cell apoptosis by reducing oxidative stress, maintain vascular endothelial function and homeostasis by inhibiting inflammation and glycocalyx degradation, and protect vascular endothelial cells by reducing iron overload. Tetramethylpyrazine also has a certain inhibitory effect on thrombosis. It can play an anti-thrombotic effect by reducing inflammatory factors and adhesion molecules, inhibiting platelet aggregation, and suppressing the expression of fibrinogen and von Willebrand factor. In addition, tetramethylpyrazine can also reduce the level of blood lipid in apolipoprotein E-deficient mice, inhibit the subcutaneous deposition of lipids, inhibit the transformation of macrophages into foam cells, and inhibit the proliferation and migration of vascular smooth muscle cells, thereby reducing the formation of atherosclerotic plaque. In combination with network pharmacology, the protective mechanism of tetramethylpyrazine on the cardiovascular system may be mainly achieved through the regulation of phosphatidylinositol 3 kinase/protein kinase B(PI3K/Akt), hypoxia-inducible factor 1(HIF-1), and mitogen-activated protein kinase(MAPK) pathways. Tetramethylpyrazine hydrochloride and sodium chloride injection has been approved for clinical application, but some adverse reactions have been found in clinical application, which need to be paid attention to.

Thermal Strain Detection for Concrete Structure Cold Shrinkage under Stress Constraint with FBG.

Additional strain increments occur in concrete subject to stress constraints during cold shrinkage, resulting in irregular deformation and reducing the concrete structure's stability. When an annular concrete structure is subjected to radial pressure, two tensile stress concentration zones will appear at the intersection of the inner wall and the diameter along the pressure direction. When exposed to low temperatures, the total strain in the tensile stress concentration zones is caused by the combined effect of applied stress strain and thermal strain. Then, the thermal strain of the structure can be obtained from the difference between the total strain and the applied stress strain. Gradient cooling was performed after applying radial pressure to the annular concrete using a counterforce device. The applied stress strain and total strain of the tensile stress concentration zones are measured by fiber Bragg grating (FBG) strain sensors fixed along the stress direction. According to the measurement results, the thermal strains of the concrete structure under the stress constraint are extracted to analyze the influence of the tensile stress constraint on the thermal strain of the concrete structure. In the temperature range of -40∘C∼20∘C, the thermal strains of the structure under radial pressures of 1500 N, 2000 N, and 3000 N are extracted, respectively. The thermal expansion coefficients are calculated based on the thermal strain of the structure. The free thermal expansion coefficient of concrete structures fluctuates around 11×10-6/∘C. When the temperature is reduced to 10∘C, the difference between the thermal expansion coefficient under the stress constraint and the free thermal expansion coefficient is the largest. When the temperature is reduced to -20∘C, the thermal expansion coefficients under each stress condition are close to the same. The results show that the stress confinement significantly inhibits the cold shrinkage of the concrete structure, and the inhibitory effect is gradually weakened when the temperature decreases.

Detection of Lower Body for AGV Based on SSD Algorithm with ResNet.

Detection of human lower body provides an implementation idea for the automatic tracking and accurate relocation of automatic vehicles. Based on traditional SSD and ResNet, this paper proposes an improved detection algorithm R-SSD for human lower body detection, which utilizes ResNet50 instead of VGG16 to improve the feature extraction level of the model. According to the application of acquisition equipment, the model input resolution is increased to 448 × 448 and the model detection range is expanded. Six feature maps of the updated resolution network are selected for detection and the lower body image dataset is clustered into five categories for aspect ratio, which are evenly distributed to each feature detection map. The experimental results show that the model R-SSD detection accuracy after training reaches 85.1% mAP. Compared with the original SSD, the detection accuracy is improved by 7% mAP. The detection confidence in practical application reaches more than 99%, which lays the foundation for subsequent tracking and relocation for automatic vehicles.

Potential effect of tropical fruits Phyllanthus emblica L. for the prevention and management of type 2 diabetic complications: a systematic review of recent advances.

Phyllanthus emblica is a fruit widely consumed in subtropical areas, which is rich in polyphenols and other nutrients. There are increasing evidences that as a daily and nutritious fruit, it may have a positive role in controlling diabetic complications. According to the new study, its mechanisms include enhancing the functioning of insulin, reducing insulin resistance, activating the insulin-signaling pathway, protecting ß-cells, scavenging free radicals, alleviating inflammatory reactions, and reducing the accumulation of advanced glycation end products. Owing to its few side effects, and low price, it should be easily accepted by patients and has potential for preventing diabetes. Taken together, Phyllanthus emblica may be an ideal fruit for controlling diabetic complications. This review highlights the latest findings of the role of Phyllanthus emblica in anti-diabetes and its complications, especially clarifies the molecular mechanism of the chemical components related to this effect, and prospects some existing problems and future research directions.

AI-assisted CT imaging analysis for COVID-19 screening: Building and deploying a medical AI system.

The sudden outbreak of novel coronavirus 2019 (COVID-19) increased the diagnostic burden of radiologists. In the time of an epidemic crisis, we hope artificial intelligence (AI) to reduce physician workload in regions with the outbreak, and improve the diagnosis accuracy for physicians before they could acquire enough experience with the new disease. In this paper, we present our experience in building and deploying an AI system that automatically analyzes CT images and provides the probability of infection to rapidly detect COVID-19 pneumonia. The proposed system which consists of classification and segmentation will save about 30%-40% of the detection time for physicians and promote the performance of COVID-19 detection. Specifically, working in an interdisciplinary team of over 30 people with medical and/or AI background, geographically distributed in Beijing and Wuhan, we are able to overcome a series of challenges (e.g. data discrepancy, testing time-effectiveness of model, data security, etc.) in this particular situation and deploy the system in four weeks. In addition, since the proposed AI system provides the priority of each CT image with probability of infection, the physicians can confirm and segregate the infected patients in time. Using 1,136 training cases (723 positives for COVID-19) from five hospitals, we are able to achieve a sensitivity of 0.974 and specificity of 0.922 on the test dataset, which included a variety of pulmonary diseases.

Single-chip holographic beam steering for lidar by a digital micromirror device with angular and spatial hybrid multiplexing.

A digital micromirror device (DMD) based holographic beam steering technique is reported that multiplexes fine-steering binary amplitude gratings with a coarse-steering programmable blazed grating. The angular spatial light modulation (ASLM) technique encodes the spatial pattern of the binary amplitude grating at the same plane as the angular modulation set by a phase map of the DMD-based beam steering technique. The beam steering technique is demonstrated at 532 nm and implemented into a 905 nm lidar system. The results of the lidar system tests are presented, achieving a 44° field-of-view, 0.9°×0.4° (H×V) angular resolution, 1 m max distance, 1.5 kHz sampling, and 7.8 FPS video. Scalability techniques are proposed, including max distance increases to over 100 m.

Differences in the responses of flow and nutrient load to isolated and coupled future climate and land use changes.

Understanding the differences in the responses of river hydrology and water quality to climate and land use changes is particularly crucial for the development and management of water resources in the future. This study was carried out to assess the isolated and coupled effects of future climate change and land use change on the flow and nutrient load of the Xitiaoxi watershed in southeast China by applying the calibrated Hydrological Simulation Program Fortran model. Four representative concentration pathways released by the Intergovernmental Panel on Climate Change and two projected land use change scenarios were used to simulate future conditions. The results indicate that climate change would result in flow increased with an average variation of 25.2% in the future, and the increased flow would be mainly concentrated on the high flow part of the total flow duration curve. Climate change would also induce seasonal shifts to nutrient load. The effects of land use change showed that nutrient load was more sensitive than flow, made Orthophosphate load increase by 2.8%-154.7%, and flow increase by 7.2%-15.1%. The results for coupled climate and land use changes indicate that flow and nutrient load would be more affected by climate change than by land use change. Climate and land use changes may amplify or weaken each other's effects on flow and nutrient load, which suggests that both should be incorporated into hydrologic models when studying the future conditions. The results of this study can help decision-makers guide management practices that aim to minimize flow and nutrient load.

Inhibitory role of lentivirus-mediated aquaporin-4 gene silencing in the formation of glial scar in a rat model of traumatic brain injury.

Traumatic brain injury (TBI), an acute degenerative pathology of the central nervous system, is a leading cause of death and disability. As the glial scar is a mechanical barrier to nerve regeneration, inhibitory molecules in the forming scar and methods to overcome them have suggested molecular modification strategies to allow neuronal growth and functional regeneration. Herein, we aim to investigate the effects of aquaporin-4 (AQP4) gene silencing on the glial scar formation after TBI by establishing rat models. After modeling, TBI rats were transfected with AQP4 small hairpin RNA [shRNA] (AQP4 gene silencing by lentiviral vector-delivered shRNA) and empty vectors, respectively. Neurological functions of the rats were evaluated after TBI. The hematoxylin and eosin staining was conducted to observe histomorphological changes in rat brain tissues. The messenger RNA (mRNA) and protein expressions of glial fibrillary acidic protein (GFAP), vimentin, fibronectin, laminin, and AQP4 were measured by reverse transcription-quantitative polymerase chain reaction and Western blot analysis. The ratio of positive expression area was calculated, and the glial scar was observed by immunohistochemistry. At the 7th, 14th, and 28th days after TBI, TBI rats treated with AQP4 shRNA showed improved neurological function and lessened histomorphological changes. AQP4 gene silencing mediated by lentivirus decreased the mRNA and protein expressions of GFAP, vimentin, fibronectin, and laminin, the number of positive cells, the ratio of positive expression area, and the glial scar. Our study demonstrates that lentivirus-mediated AQP4 gene silencing could inhibit the formation of glial scar after TBI, which is beneficial to the recovery of neurological function.

A Potential Anti-Tumor Herb Bred in a Tropical Fruit: Insight into the Chemical Components and Pharmacological Effects of Momordicae Semen.

Gac fruit (Momordica cochinchinensis Spreng) is a popular tropical fruit in southeast Asia. What is amazing is that its seeds (Momordicae Semen) and arils are traditional herbs with anti-tumor activity, and have protected human health for more than 1000 years. In recent years, its anti-tumor activity has received extensive attention and research. This manuscript summarized the chemical composition of saponins, fatty acids, volatile constituents, proteins, peptides, and other components from Momordicae Semen (MSE). The effect and mechanism of MSE and its extract on breast cancer, gastric cancer, lung cancer, esophagus cancer, melanomas, and human cervical epithelial carcinoma were discussed. In addition, its antioxidant, anti-inflammatory, and other pharmacological effects were also analyzed. We hope that this review will provide new ideas for the treatment of cancer and other diseases, and become a reference for the further research into complementary and alternative medicine.

Seeing the Unseen of the Combination of Two Natural Resins, Frankincense and Myrrh: Changes in Chemical Constituents and Pharmacological Activities.

For the treatment of diseases, especially chronic diseases, traditional natural drugs have more effective therapeutic advantages because of their multi-target and multi-channel characteristics. Among many traditional natural medicines, resins frankincense and myrrh have been proven to be effective in the treatment of inflammation and cancer. In the West, frankincense and myrrh have been used as incense in religious and cultural ceremonies since ancient times; in traditional Chinese and Ayurvedic medicine, they are used mainly for the treatment of chronic diseases. The main chemical constituents of frankincense and myrrh are terpenoids and essential oils. Their common pharmacological effects are anti-inflammatory and anticancer. More interestingly, in traditional Chinese medicine, frankincense and myrrh have been combined as drug pairs in the same prescription for thousands of years, and their combination has a better therapeutic effect on diseases than a single drug. After the combination of frankincense and myrrh forms a blend, a series of changes take place in their chemical composition, such as the increase or decrease of the main active ingredients, the disappearance of native chemical components, and the emergence of new chemical components. At the same time, the pharmacological effects of the combination seem magically powerful, such as synergistic anti-inflammation, synergistic anticancer, synergistic analgesic, synergistic antibacterial, synergistic blood-activation, and so on. In this review, we summarize the latest research on the main chemical constituents and pharmacological activities of these two natural resins, along with chemical and pharmacological studies on the combination of the two.

Winter plant phenology in the alpine meadow on the eastern Qinghai-Tibetan Plateau.

Background and Aims: There is no knowledge of winter plant phenology and its controlling factors on the Qinghai-Tibetan Plateau (QTP). Thus, we conducted a 4 year winter phenology and growth dynamics study in the alpine meadow on the eastern QTP. Methods: From November 2013 to March 2017, the phenology of the 'winter-growth' and 'winter-green' species was recorded every 5 d. In November-February from 2014 to 2015, the above-ground biomass (AGB) in random plots was calculated to distinguish different growth patterns among winter growing species. The percentage of winter abundance relative to the summer population for forbs and the percentage of absolute coverage for grasses (W/S) were calculated to describe the importance of the winter population to the summer population. The soil moisture (SM) and soil temperature (ST) were used to explore the controlling factors on the AGB. Pearson's correlation analysis between winter phenology data and environmental variables, including air temperature (Tair), snow cover fraction (SCF), SM and ST, was used to investigate the factors affecting winter phenology during November-February from 2014 to 2017. Key Results: There were 107 species in total in the sites, including ten 'winter-growth' species and four 'winter-green' species. Among the 'winter-green' species, Festuca ovina and Deschampsia cespitosa were the dominant species in the sites. The 'winter-growth' species grew new leaves or ramets or transitioned to reproductive growth. Gentiana spathulifolia even flowered in winter. 'Winter-growth' made important contributions to the annual AGB, e.g. winter growth of G. spathulifolia accounted for 23.26 % of its annual AGB, while 14.74 % of the annual AGB of G. crassuloides was from winter growth. In addition, winter warming and snowfall reduction under global climate change on the eastern QTP may decrease the AGB increment of the 'winter-growth' and delay the green-up onset date of 'winter-green' species. Also, winter warming and snowfall reduction may advance the first flowering date of 'winter-growth' species. Conclusions: In contrast to previous views that plants on the QTP were generally considered to remain dormant in winter, our study revealed that alpine meadow plants had strong winter growth which suggested the importance of re-evaluating the dynamics of ecosystem function of alpine meadow, including its contribution to the global carbon balance. It was also shown that soil moisture availability is more important than warmer temperature in controlling the green-up onset of 'winter-green' species on the eastern QTP, which contrasts with the traditional view that warmer winters could advance green-up. As snowmelt is the only source of soil water in winter, the prediction of the green-up trend may be further complicated by snowfall variation in winter.

[Difference of Liver Enzymes in Different Metabolism States of Chronic Hepatitis B].

OBJECTIVE: To analyze the difference of liver enzymes in different metabolism state groups of chronic hepatitis B (CHB). METHODS: We use prospective cross-sectional study to analyze the difference of liver enzymes in different metabolism state groups in 110 cases of CHB, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and glutamyl transferase (GGT). RESULTS: Regardless of the presence or absence of fatty liver, the levels of ALP and GGT were increased along with the deterioration of glucose metabolism (P<0.05).The levels of ALP and GGT in the presence of fatty liver group were higher than those in the absence of fatty liver group (P<0.05). The levels of AST, ALP and GGT showed the trend of increasing along with the increase of HOMA-IR and the decrease of HOMA-ß. There was no difference of liver enzymes among the groups with or without other metabolism disorder (P>0.05). CONCLUSION: In CHB, abnormal glucose metabolism and fatty liver can lead to the increase of ALP and GGT. The increase of HOMA-IR and the decrease of HOMA-ß may lead to the increase of AST, ALP and GGT. Other metabolism disorder did not show any effect on the level of liver enzymes.

Placement-induced effects on high tibial osteotomized construct - biomechanical tests and finite-element analyses.

BACKGROUND: High tibial osteotomy (HTO) with a medially opening wedge has been used to treat osteoarthritic knees. However, the osteotomized tibia becomes a highly unstable structure and necessitates the use of plate and screws to stabilize the medial opening and enhance bone healing. A T-shaped plate (e.g. TomoFix) with locking screws has been extensively used as a stabilizer of the HTO wedge. From the biomechanical viewpoint, however, the different plate sites and support bases of the HTO plate should affect the load-transferring path and wedge-stabilizing ability of the HTO construct. This study uses biomechanical tests and finite-element analyses to evaluate the placement- and base-induced effects of the HTO plates on construct performance. METHODS: Test-grade synthetic tibiae are chosen as the standard specimens of the static tests. A medial wedge is created for each specimen and stabilized by three plate variations: hybrid use of T- and I-shaped plates (TIP), anteriorly placed TomoFix (APT), and medially placed TomoFix (MPT). There are five tests for each variation. The failure loads of the three constructs are measured and used as the load references of the fatigue finite-element analysis. The residual life after two hundred thousand cycles is predicted for all variations. RESULTS: The testing results show no occurrence of implant back-out and breakage under all variations. However, the wedge fracture consistently occurs at the opening tip for the APT and MPT and the medially resected plateau for the TIP, respectively. The testing results reveal that both failure load and wedge stiffness of the TIP are the highest, followed by the MPT, while those of the APT are the least (P < 0.05). The fatigue analyses predict comparable values of residual life for the TIP and MPT and the highest value of damage accumulation for the APT. Both experimental and numerical tests show the biomechanical disadvantage of the APT than their counterparts. However, the TIP construct without locking screws shows the highest stress at the plate-screw interfaces. CONCLUSIONS: This study demonstrates the significant effect of placement site and support base on the construct behaviors. The TIP provides a wider base for supporting the HTO wedge even without the use of locking screws, thus significantly enhancing construct stiffness and suppressing wedge fracture. Compared to the APT, the MPT shows performance more comparable to that of the TIP. If a single plate and a smaller incision are considered, the MPT is recommended as the better alternative for stabilizing the medial HTO wedge.