Human Muscle-Derived Cells Are Capable of Tenogenic Differentiation and Contribution to Tendon Repair.

BACKGROUND: It has been reported that the harvested hamstring tendon for autograft could be regenerated with well-oriented fibers and uniformly distributed spindle-shaped cells after removal. However, which cell type might participate in the repair process remains unknown. PURPOSE: To investigate the tenogenic differentiation potential of human muscle-derived cells (MDCs) both in vitro and in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: Primary human MDCs and tenocytes were isolated from discarded materials during a peroneus longus tendon-harvesting procedure. Expression of tenogenic genes were evaluated and compared among MDCs, MDCs with tenogenic induction, and tenocytes. RNA sequencing was performed to evaluate the expression profile of differentiated MDCs. Human MDCs were implanted in a tendon injury model to investigate the in vivo tenogenic differentiation potential. Histologic and functional analyses were performed to evaluate the function of MDCs for tendon repair. RESULTS: The relative expression levels (in fold change) of tenogenic genes Col I, MKX, SCX, THBS4, and TNC in MDCs were significantly upregulated 11.5 ± 1.3, 957.1 ± 63.7, 19.1 ± 2.8, 61.9 ± 4.8, and 10.2 ± 2.8 after tenogenic induction, respectively. The expression profile of tenogenically differentiated MDCs was much closer to primary tenocytes. Activation of TGF-ß/Smad3 signaling significantly promoted the tenogenic differentiation ability of MDCs. Transplanted human MDCs were identified in regenerated tendon and expressed tenogenic genes. As for biomechanical properties, the failure loads in the Matrigel, transplantation, and uninjured groups were 7.2 ± 0.5, 11.6 ± 0.3, and 13.9 ± 0.7 N, while the stiffness values were 4.4 ± 1.3 × 103, 7.6 ± 0.8 × 103, and 10.9 ± 1.1 × 103 N/m. Plantarflexion force, histologic morphology, and motor function were also significantly improved after MDC transplantation in a tendon injury model. CONCLUSION: There exist cells with tenogenic differentiation potential in human skeletal muscles. Activation of TGF-ß/Smad3 signaling plays an important role in tenogenic differentiation for human MDCs. Human MDCs contribute to structural and functional repair for the injured tendon. MDCs are a potential cell source to participate in the repair process after tendon injury. CLINICAL RELEVANCE: The MDCs could be a promising cell source to repair tendon injury.

Arthroscopic repair of degenerative medial meniscus tears in patients aged over 45 years resulted in favorable clinical outcomes and low clinical failure rates at a minimum 2-year follow-up.

PURPOSE: This study aimed to investigate clinical and radiological results of arthroscopic repair for isolated medial degenerative meniscus tears (DMTs) in patients over 45 years old at a minimum 2-year follow-up. METHODS: From 2013 to 2017, patients aged over 45 years with isolated medial DMT refractory to conservative management or with true mechanical symptoms who had undergone arthroscopic repair were retrospectively reviewed. Arthroscopic meniscus repair was performed using all-inside or all-inside and inside-out technique in combination with bone marrow venting procedure. Tear patterns were classified according to arthroscopic findings. Magnetic resonance imaging (MRI) and outcome evaluations, including Lysholm score, Tegner activity score, and International Knee Documentation Committee (IKDC) score, were evaluated preoperatively and at the final follow-up. International Cartilage Repair Society grades of the medial compartments and MRI signal at tear sites were assessed preoperatively and at the final follow-up. A grade 0 to 2 signal at the repair site suggested a healed meniscus, whereas a grade 3 signal suggested an unhealed meniscus. Clinical failure was determined according to Barrett criteria. RESULTS: Twenty-seven patients (mean age, 57.7 ± 7.4 years) were enrolled. The mean follow-up was 52.0 ± 15.6 months. Among tear patterns, 48% were complex tears, 30% were horizontal tears, and 22% were other patterns. The mean Lysholm score and IKDC score significantly improved from 53 ± 25 to 89 ± 15 (p < 0.001) and 34 ± 24 to 72 ± 15 (p < 0.001) at the final follow-up, respectively. The median Tegner activity score significantly improved from 1 (range 1-4) to 4 (range 2-7, p < 0.001). Three (11%) patients were considered clinical failures, and five patients (19%) had cartilage lesion progression. At the final follow-up, MRI showed grade 0 in one (4%) patient, grade 1 in nine (33%) patients, grade 2 in six (22%) patients, and grade 3 in eleven (41%) patients. CONCLUSION: Arthroscopic repair of isolated medial DMT refractory to conservative management or with true mechanical symptoms in patients aged over 45 years had good to excellent clinical outcomes with low clinical failure rates, despite unhealed menisci being observed on MRI in 41% of patients at a mean 4.3-year follow-up. Arthroscopic repair could be a treatment option for these patients. LEVEL OF EVIDENCE: IV.

Evaluation of iron-loaded granular activated carbon used as heterogeneous fenton catalyst for degradation of tetracycline.

To optimize the efficiency of general adsorption-Fenton oxidation treatment, iron-loaded granular activated carbon (Fe-GAC) was prepared, characterized, and used as a catalyst in the heterogeneous Fenton oxidation of tetracycline (TC). Characterization revealed that the Fe(II) was successfully introduced onto the original granular activated carbon (GAC) and diversified the materials' surface morphology and elemental compounds. Under an initial pH of 3.0, the Fe-GAC/Fenton system obtained a maximum removal rate of 92.6%, with hydrogen peroxide (H2O2) dosages of 9 mmol g-1. And the GAC/Fenton without iron supplementation was 89.5%, with H2O2 dosages of 8 mmol g-1. Additionally, the Fe-GAC/Fenton system consumed a lower Fe(II) dosage than GAC/Fenton, with Fe(II)/H2O2 molar ratios of 0.007:1 and 0.04:1, respectively. Analysis of total organic carbon demonstrated higher mineralization efficiency in the Fe-GAC/Fenton system (67.2%), which was approximately 1.3 times of GAC/Fenton. Desorption experiments showed that the adsorption and degradation accounted for 19.22% and 80.78% of the total TC removal by GAC/Fenton, and 10.58% and 89.42% in the Fe-GAC/Fenton system, respectively. Electron paramagnetic resonance (EPR) technique and quenching experiments demonstrated that the dominant reactive oxygen species (ROS) in synergistic treatments were hydroxyl (•OH) and hydroxy peroxyl (HO2•) radicals. In addition, three potential degradation pathways for TC were proposed according to the detected fourteen intermediates. Catalyst regeneration treatments were evaluated over six cycles, and the regeneration was 6.5% higher with the iron-supplemented carbon granules. Overall, the Fe-GAC can be used as an efficient catalyst in practical water treatment, and this study demonstrated a promising method to develop adsorption-Fenton technology.

YTH Domain Proteins Play an Essential Role in Rice Growth and Stress Response.

As the most prevalent epi-transcriptional modification, m6A modifications play essential roles in regulating RNA fate. The molecular functions of YTH521-B homology (YTH) domain proteins, the most known READER proteins of m6A modifications, have been well-studied in animals. Although plants contain more YTH domain proteins than other eukaryotes, little is known about their biological importance. In dicot species Arabidopsis thaliana, the YTHDFA clade members ECT2/3/4 and CPSF30-L are well-studied and important for cell proliferation, plant organogenesis, and nitrate transport. More emphasis is needed on the biological functions of plant YTH proteins, especially monocot YTHs. Here we presented a detailed phylogenetic relationship of eukaryotic YTH proteins and clustered plant YTHDFC clade into three subclades. To determine the importance of monocot YTH proteins, YTH knockout mutants and RNAi-induced knockdown plants were constructed and used for phenotyping, transcriptomic analysis, and stress treatments. Knocking out or knocking down OsYTHs led to the downregulation of multicellular organismal regulation genes and resulted in growth defects. In addition, loss-of-function ythdfa mutants led to better salinity tolerance whereas ythdfc mutants were more sensitive to abiotic stress. Overall, our study establishes the functional relevance of rice YTH genes in plant growth regulation and stress response.

The biomechanical analysis of three-dimensional distal radius fracture model with different fixed splints.

BACKGROUND: The distal radius fracture is one of the common clinical fractures. At present, there are no reports regarding application of the finite element method in studying the mechanism of Colles fracture and the biomechanical behavior when using splint fixation. OBJECTIVE: To explore the mechanism of Colles fracture and the biomechanical behavior when using different fixed splints. METHODS: Based on the CT scanning images of forearm for a young female volunteer, by using model construction technology combined with RPOE and ANSYS software, a 3-D distal radius fracture forearm finite element model with a real shape and bioactive materials is built. The material tests are performed to obtain the mechanical properties of the paper-based splint, the willow splint and the anatomical splint. The numerical results are compared with the experimental results to verify the correctness of the presented model. Based on the verified model, the stress distribution of different tissues are analyzed. Finally, the clinical tests are performed to observe and verify that the anatomical splint is the best fit for human body. RESULTS: Using the three kinds of splints, the transferred bone stress focus on the distal radius and ulna, which is helpful to maintain the stability of fracture. Also the stress is accumulated in the distal radius which may be attributed to flexion position. Such stress distribution may be helpful to maintain the ulnar declination. By comparing the simulation results with the experimental observations, the anatomical splint has the best fitting to the limb, which can effectively avoid the local compression. CONCLUSION: The anatomical splint is the most effective for fixing and curing the fracture. The presented model can provide theoretical basis and technical guide for further investigating mechanism of distal radius fracture and clinical application of anatomical splint.

Comparative study on turbulence models simulating inorganic particle removal in a Pista grit chamber.

Numerical simulations and experimental validations were conducted to determine grit removal efficiency and separation processes for inorganic suspended solids (ISS) with different particle sizes in a vortex-type grit chamber (Pista). The Euler-Lagrange method was used to simulate solid-liquid two-phase flow; the Unsteady Discrete Model was used to simulate the solid phase; and the Renormalization Group k-epsilon (RNG k-ε), Realizable k-epsilon (Real k-ε), and Shear Stress Transmission k-ω (SST k-ω) models were used to simulate the liquid phase. Results of the RNG k-ε model agreed well with the experimental results for particles with d ≤ 200 µm, with an average error of 7.10% (d < 100 µm) and 6.78% (100 µm ≤ d ≤ 200 µm). When particle size exceeded 200 µm, the Real k-ε model had the minimum average error (4.16%). Bed load transport and suspended load transport of the different size ISS particles presented in the grit chamber were important factors influencing grit removal efficiency. Pressure gradient and turbulence intensity distributions simulated by the three turbulence models were significantly different. Particles with diverse sizes reacted distinctly to the disturbance effect caused by pressure difference, which impacted on the accuracy and reliability of simulation results.

[Effectiveness of arthroscopic capsular release to treat primary severe frozen shoulder through trans cuff portal].

Objective: To assess the effectiveness of arthroscopic capsular release to treat primary severe frozen shoulder through trans cuff portal. Methods: Between June 2012 and January 2015, 28 patients with primary severe frozen shoulder were enrolled in the study. There were 8 males and 20 females with an average age of 57 years (range, 42-81 years). The left shoulder was involved in 16 cases and the right one in 12 cases. The mean disease duration was 11 months (range, 7-21 months). Six patients had diabetes. All patients underwent arthroscopic capsular release by trans cuff portal. The range of motion (ROM) of the shoulder were measured at preoperation and at 6 weeks and 24 months after operation; the scores of American Shoulder and Elbow Surgeons (ASES) and visual analogue scale (VAS) were used to evaluate the shoulder function and pain. Results: Primary healing of incision was obtained, and no complications of infection, shoulder instability, and nerve injury were found. All patients were followed up 24 months. Pain of the shoulder was obviously relieved; VAS score was significantly lower at 6 weeks and 24 months after operation than preoperation ( P<0.05), and at 24 months than 6 weeks ( P<0.05). ROM of the shoulder and ASES score at 6 weeks and 24 months after operation were significantly increased when compared with preoperative ones ( P<0.05); significant difference was found in ROM of forward flexion and external rotation and the ASES score between at 6 weeks and 24 months ( P<0.05). And internal rotation in-creased from trochanter (9 cases), hip (6 cases), sacrum (7 cases), and L 4 vertebral level (6 cases) before operation to the T 12-T 6 vertebral level at 6 weeks and 24 months after operation, which were close to normal side. Conclusion: Arthroscopic capsular release through trans cuff portal is an effective and safe management for primary severe frozen shoulder.

Sandwich-style posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the results of a sandwich-style posterior cruciate ligament (PCL) reconstruction, namely double-bundle PCL reconstruction with 8 strands of hamstring tendons and remnant preservation. METHODS: Eighteen cases of isolated chronic PCL rupture were reconstructed arthroscopically with 8 strands of autogenous hamstring tendons by way of 2-bundle and 4-tunnel reconstruction, as well as preservation of the remnant between the 2 reconstructed bundles. Quadruple-stranded semitendinosus tendon was used to reconstruct the anterolateral bundle, and quadruple-stranded gracilis tendon was used to reconstruct the posteromedial bundle. The grafts were fixed with a suspension technique by mini-plates and mini-buttons. The patients were followed up for a minimum of 2 years and evaluated according to the International Knee Documentation Committee (IKDC), Lysholm, and Tegner rating scales. RESULTS: At a minimum of 2 years after surgery, 17 patients (94.4%) had a negative posterior drawer test and 1 had a 1+ posterior drawer test. The mean KT-1000 examination results (MEDmetric, San Diego, CA) changed from 9.3 +/- 1.4 mm preoperatively to 0.7 +/- 0.9 mm postoperatively (P < .001). According to the IKDC knee examination form, the results were graded as normal in 16 patients (88.9%) and nearly normal in 2 (11.1%). The IKDC subjective results increased from 64.1 +/- 3.3 to 95.6 +/- 3.1 (P < .001), and the Lysholm score increased from 58.6 +/- 4.4 to 94.9 +/- 3.6 (P < .001). The mean Tegner score was 7.1 before injury, 5.6 before surgery, and 6.9 at the last follow-up. CONCLUSIONS: Arthroscopic sandwich-style PCL reconstruction can yield normal results in 88.9% of patients and nearly normal results in 11.1% at a minimum of 2 years.