No difference in postoperative efficacy and safety between autograft and allograft in anterior cruciate ligament reconstruction: a retrospective cohort study in 112 patients.

Background: Arthroscopic anterior cruciate ligament reconstruction (ACLR) is the best treatment choice for returning to pre-injury activities following ACL rupture. Although allografts are considered an effective alternative to autografts, there is still controversy regarding the safety and effectiveness of this procedure, especially concerning the risk of postoperative infection and disease transmission. The purpose of this study was to compare the efficacy outcomes and safety between allografts and autografts in primary ACLR. Methods: The retrospective analysis involved 112 patients (58 patients received allogeneic tendons and 54 patients received autologous hamstring tendons) who underwent primary ACLR. All patients were followed up and evaluated on admission and at 1 week, 3 months, 6 months, and 1 year postoperatively. The efficacy outcome of the ACLR was evaluated by International Knee Documentation Committee (IKDC) score and physical examinations (Lachman test, anterior drawer test, and pivot shift test). The safety outcome of allografts and autografts was compared by investigating the occurrence of postoperative complications, including postoperative inflammation and potential disease transmission. The benefits of each operation for surgeons and patients were also analyzed, including the length of surgical incision and operative time. Results: There was no significant difference in the demographic and clinical characteristics between the allograft and autograft groups. The two cohorts proved to be similar in terms of the acute or chronic nature of the cruciate ligament and the incidence of concomitant meniscal surgery. Arthroscopic ACLR was performed in all patients. The physical examinations were all positive before surgery and negative immediately after the operation. The KT-1000 and IKDC scores of two groups significantly decreased than pre-operative ones (P<0.05), but the difference between the two groups was not statistically significant (P>0.05). At final follow-up, all patients had returned to their pre-injury activities. Allografts showed no increased risk for postoperative infection or potential disease transmission relative to autografts. Conclusions: The outcomes of reconstructed ACL with allografts were similar to those of autographs. Moreover, the safety of allografts showed to be comparable to that of autografts, especially concerning postoperative infection and disease transmission. Therefore, the surgical option should be chosen wisely according to the patient's condition.

In situ forming hydrogel of natural polysaccharides through Schiff base reaction for soft tissue adhesive and hemostasis.

In this study, a novel injectable hydrogel with biocompatibility and biodegradability through Schiff base reaction was prepared for soft tissue adhesive and hemostasis. Aldehyde hydroxyethyl starch (AHES) was prepared by oxidizing hydroxyethyl starch to get aldehyde groups. Amino carboxymethyl chitosan (ACC) was prepared by grafting ethylenediamine onto carboxymethyl chitosan to get more amino groups. Two-component AHES/ACC hydrogel was formed through Schiff base reaction between aldehyde and amino groups. By changing the reaction conditions various contents of aldehyde and amino group were achieved. The properties of AHES/ACC hydrogel were tunable including gelation time, swelling ratio, degradation and mechanical tensile by varying the content of aldehyde and amino groups. Then biocompatibility measurements showed that AHES/ACC hydrogels supported cell viability and proliferation in vitro and exhibited good biodegradability and biocompatibility in vivo. AHES/ACC hydrogel also had effective hemostatic ability. Thus, this study provides a strategy for the design and fabrication of fast in situ forming hydrogels. Through Schiff base reaction in situ forming hydrogel derived from natural polysaccharides can be modulated and prepared for soft tissue adhesive, hemostasis or other biomedical applications in future.

Moist-Retaining, Self-Recoverable, Bioadhesive, and Transparent in Situ Forming Hydrogels To Accelerate Wound Healing.

In the management of accelerating wound healing, moist environments play an important role. Compared with other scaffolds of various forms, hydrogels can maintain a moist environment in the wound area. They are cross-linked hydrophilic polymeric networks that resemble natural soft tissues and extracellular matrices. Among them, injectable hydrogels have attracted great attention in wound repair, as they can be injected into irregular-shaped skin defects and formed in situ to shape the contour of different dimensions. The excellent compliance makes hydrogels easy to adapt to the wound under different conditions of skin movement. Here, we oxidized hydroxyethyl starch (O-HES) and modified carboxymethyl chitosan (M-CMCS) to fabricate an in situ forming hydrogel with excellent self-recoverable extensibility-compressibility, biocompatibility, biodegradability, and transparency for accelerating wound healing. The oxidation degree of O-HES was 74%. The amino modification degree of M-CMCS was 63%. M-CMCS/O-HES hydrogels were formed through the Schiff base reaction. The physicochemical properties of M-CMCS/O-HES hydrogels with various ratios were investigated, and M-CMCS/O-HES hydrogel with a volume ratio of 5:5 exhibited appropriate gelation time, notable water-retaining capacity, self-recoverable conformal deformation, suitable biodegradability, and good biocompatibility for wound-healing application. Then, skin wound-healing experimental studies were carried out in Sprague-Dawley rats with full-thickness skin defects. Significant outcomes were achieved in the M-CMCS/O-HES hydrogel-treated group including higher wound closure percentage, more granulation tissue formation, faster epithelialization, and decreased collagen deposition. These findings demonstrate that using the obtained M-CMCS/O-HES hydrogels is a promising therapeutic strategy for wound healing.

Plate fixation for Letenneur type I Hoffa fracture: a biomechanical study.

BACKGROUND: A coronal fracture of the posterior femoral condyle, also known as a Hoffa fracture, is an unusual injury, and there are only a handful of case reports or series exploring it. The optimal fixation method of these intraarticular fractures remains controversial; improper or unstable fixation usually lead to an unsatisfactory prognosis. The use of posterior-anterior or reversed lag screw fixation is still a popular method. Additional buttress plating is also recommended for fixation of these difficult fractures. The purpose of this study was to compare the mechanical strength of four different fixation patterns for this uncommon fracture. MATERIAL AND METHODS: Sixteen sawbone simulated models of Letenneur type I Hoffa fractures were created with one of four fixation patterns: two screws implanted in the anterior-posterior (AP) direction or posterior-anterior (PA) direction; one screw in the PA direction with a plate implanted in the posterior position of the distal femoral condyle or with a plate in the lateral position. Biomechanical testing was performed to determine the post-fixation axial stiffness, the maximum load to failure and the fragment vertical displacement for each of the four constructs. RESULTS: The plate fixation patterns whether implanted in the posterior or lateral position were shown to provide higher overall axial stiffness and load to failure, and less vertical displacement than the other two patterns of pure screw fixation. Among these constructs, the lateral plate fixation was found to provide the highest stiffness and load to failure and the least displacement for the posterior condylar fragments, followed by the posterior plate fixation. The lowest overall stiffness and load to failure and the largest vertical displacement were found in the construct with the AP direction placed screws. CONCLUSION: It was concluded that the lateral position implanted plate is biomechanically the strongest fixation method for Letenneur type I Hoffa fractures. However, this plate fixation is not recommended for all cases. The choice of internal fixation pattern depends on the surgeons.

Characterization and cytocompatibility of thermosensitive hydrogel embedded with chitosan nanoparticles for delivery of bone morphogenetic protein-2 plasmid DNA.

A novel injectable chitosan thermosensitive hydrogel was designed as a target multi-effect scaffold for endogenous repair of the periodontium. The hydrogel complex was designed by embedding chitosan nanoparticles (CSn) loaded with bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2) into a chitosan (CS)-based hydrogel with α,ß-glycerophosphate (α,ß-GP), termed CS/CSn(pDNA-BMP2)-GP. Characterization, the in vitro release profile for pDNA-BMP2, and cytocompatibility to human periodontal ligament cells (HPDLCs), were then conducted. The average diameter of the CSn(pDNA-BMP2) was 270.1 nm with a polydispersity index (PDI) of 0.486 and zeta potential of +27.0 mv. A DNase I protection assay showed that CSn could protect the pDNA-BMP2 from nuclease degradation. Encapsulation efficiency and loading capacity of CSn(pDNA-BMP2) were more than 80 and 30 %, respectively. The sol-gel transition time was only 3 min when CSn(pDNA-BMP2) was added into the CS/α,ß-GP system. Scanning electron microscopy showed that CSn(pDNA-BMP2) was randomly dispersed in a network with regular holes and a porous structure. Weighting method showed the swelling ratio and degradation was faster in medium of pH 4.0 than pH 6.8. An in vitro pDNA-BMP2 release test showed that the cumulative release rate of pDNA-BMP2 was much slower from CS/CSn-GP than from CSn in identical release media. In release media with different pH, pDNA-BMP2 release was much slower at pH 6.8 than at pH 4.0. Three-dimensional culture with HPDLCs showed good cell proliferation and the Cell-Counting Kit-8 assay indicated improved cell growth with the addition of CSn(pDNA-BMP2) to CS/α,ß-GP. In summary, the CS/CSn(pDNA-BMP2)-GP complex system exhibited excellent biological properties and cytocompatibility, indicating great potential as a gene delivery carrier and tissue regeneration scaffold for endogenous repair of the periodontium.

Antibodies to Type IV Collagen Induce Type 1 Autoimmune Pancreatitis.

Type 1 autoimmune pancreatitis (AIP) is prototypic autoantibody-mediated diseases. Sclerosis accompanied by fiber deposition is generally regarded as the primary lesion in the development of obliterative vasculitis. However, why collagens or their antibodies play a crucial role in the pathogenesis of AIP has not been demonstrated. This study was performed to investigate if anti-collagen type IV antibodies (ACIVAbs) are the key factor of fiber deposition and recruit leukocytes, resulting in obliterative vasculitis in pancreas. Enzyme-linked immunosorbent analyses (ELISA) were used to measure the expression of Col IV and ACIVAbs in serum of patients with and without AIP. In vitro, adhesion and proliferation were determined by human lymphocytes incubated with Col IV and ACIVAbs. In vivo, C57BL0/6 mice were immunized with IgG-ACIVAbs, followed by analysis of clinical phenotype. IgG-ACIVAbs were recognized by the serum specimens from 12 of 22 patients with type 1 AIP, 3 of 9 patients with Crohn's disease, and 2 of 18 patients with pancreatic cancer, but not in healthy controls and acute pancreatitis. In patient's biopsy, ACIVAb staining increased and co-localized with subepithelial IgG4 deposits along the capillary walls and surrounding nerve fibers. In vitro, recombinant IgG-ACIVAbs increased leukocyte adhesion and proliferation. What is more, AIP could be induced in mice by immunization with IgG-ACIVAbs into adult mice.

Application of avidin-biotin technology to improve cell adhesion on nanofibrous matrices.

BACKGROUND: Electrospinning is an easy and effective technique to produce submicron fibers possessing a range of attractive characteristics such as interconnected porous structures similar to natural ECM and good resilience to movement. Rapid and efficient cell attachment to nanofibrous matrices is a necessary prerequisite in tissue engineering. Thus, the aim of this study is to evaluate poly(ε-caprolactone-co-lactide)/Pluronic (PLCL/Pluronic) nanofibrous matrices with avidin-biotin technology for improving cell adhesion for the first time. RESULTS: PLCL/Pluronic nanofibers had relatively homogeneous fibers and interconnected porous structures. Pluronic significantly modified the hydrophilicity of nanofibrous matrices and PLCL/Pluronic nanofibrous matrices had better performance on maintaining cell proliferation. Avidin-biotin technology had no negative effect on the hydrophilic property, mechanical property and cell proliferation. Meanwhile, the attachment and spreading of adipose-derived stem cells (ADSCs) onto PLCL/Pluronic nanofibrous matrices with avidin-biotin technology was promoted obviously. CONCLUSIONS: PLCL/Pluronic nanofibrous matrices inheriting the excellent characteristics of both PLCL and Pluronic have the better cell adhesion ability through avidin-biotin technology, implying a promising application in skin care, tissue regeneration and other related area.

Protective effects of total saponins of panax notoginseng on steroid-induced avascular necrosis of the femoral head in vivo and in vitro.

This research was designed to investigate the protective effects of TSPN on steroid-induced avascular necrosis of the femoral head (ANFH) and the likely mechanisms of those effects. As an in vivo study, TSPN was shown to be protective against steroid-induced ANFH due to the upregulation of VEGF-A. Furthermore, TSPN attenuated the apoptosis of osteocytes and reduced the expression of Caspase-3 relative to the model group. As an in vitro study, TSPN exerted a concentration-dependent protective effect against apoptosis in MC3T3-E1 cells. Moreover, TSPN (at a dose of 100 µg/mL) significantly reversed the dexamethasone-induced augmentation of Caspase-3 expression and activity. Therefore, our study demonstrated that TSPN had a protective effect against steroid-induced ANFH that was related to the upregulation of VEGF-A and the inhibition of apoptosis and Caspase-3 activation.

Evaluation of synovium-derived mesenchymal stem cells and 3D printed nanocomposite scaffolds for tissue engineering.

Stem cells and scaffolds play a very important role in tissue engineering. Here, we isolated synovium-derived mesenchymal stem cells (SMSCs) from synovial membrane tissue and characterized stem-cell properties. Gelatin nanoparticles (NP) were prepared using a two-step desolvation method and then pre-mixed into different host matrix (silk fibroin (SF), gelatin (Gel), or SF-Gel mixture) to generate various 3D printed nanocomposite scaffolds (NP/SF, NP/SF-Gel, NP/Gel-1, and NP/Gel-2). The microstructure was examined by scanning electron microscopy. Biocompatibility assessment was performed through CCK-8 assay by coculturing with SMSCs at 1, 3, 7 and 14 days. According to the results, SMSCs are similar to other MSCs in their surface epitope expression, which are negative for CD45 and positive for CD44, CD90, and CD105. After incubation in lineage-specific medium, SMSCs could differentiate into chondrocytes, osteocytes and adipocytes. 3D printed nanocomposite scaffolds exhibited a good biocompatibility in the process of coculturing with SMSCs and had no negative effect on cell behavior. The study provides a strategy to obtain SMSCs and fabricate 3D printed nanocomposite scaffolds, the combination of which could be used for practical applications in tissue engineering.

Preparation and characterization of electrospun PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels for skin tissue engineering.

In this study, two different biomaterials were fabricated and their potential use as a bilayer scaffold for skin tissue engineering applications was assessed. The upper layer biomaterial was a Poly(ε-caprolactone-co-lactide)/Poloxamer (PLCL/Poloxamer) nanofiber membrane fabricated using electrospinning technology. The PLCL/Poloxamer nanofibers (PLCL/Poloxamer, 9/1) exhibited strong mechanical properties (stress/strain values of 9.37 ± 0.38 MPa/187.43 ± 10.66%) and good biocompatibility to support adipose-derived stem cells proliferation. The lower layer biomaterial was a hydrogel composed of 10% dextran and 20% gelatin without the addition of a chemical crosslinking agent. The 5/5 dextran/gelatin hydrogel displayed high swelling property, good compressive strength, capacity to present more than 3 weeks and was able to support cells proliferation. A bilayer scaffold was fabricated using these two materials by underlaying the nanofibers and casting hydrogel to mimic the structure and biological function of native skin tissue. The upper layer membrane provided mechanical support in the scaffold and the lower layer hydrogel provided adequate space to allow cells to proliferate and generate extracellular matrix. The biocompatibility of bilayer scaffold was preliminarily investigated to assess the potential cytotoxicity. The results show that cell viability had not been affected when cocultured with bilayer scaffold. As a consequence, the bilayer scaffold composed of PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels is biocompatible and possesses its potentially high application prospect in the field of skin tissue engineering.

[Selection of advantage prediction model for forest fire occurrence in Tahe, Daxing'an Mountain].

This study chose zero-inflated model and Hurdle model that have been widely used in economic and social fields to model the fire occurrence in Tahe, Daxing'an Mountain. The AIC, LR and SSR were used to compare the models including zero-inflated Poisson model (ZIP), zero-inflated negative binomial model (ZINB), Poisson-Hurdle model (PH) and negative Binomial Hurdle (NBH) (two types, four models in total) so as to determine a better-fit model to predict the local fire occurrence. The results illustrated that ZINB model was superior over the other three models (ZIP, PH and NBH) based on the result of AIC and SSR tests. LR test revealed that the negative binomial distribution was suitable to both the "count" portion of zero-inflated model and hurdle model. Furthermore, this paper concluded that the zero-inflated model could better fit the fire feature of the study area according to the hypotheses of the two types of models.

Fabrication of modified dextran-gelatin in situ forming hydrogel and application in cartilage tissue engineering.

Hydrogels play a very important role in cartilage tissue engineering. Here, we oxidized dextran (Odex) and modified gelatin (Mgel) to fabricate a fast forming hydrogel without the addition of a chemical crosslinking agent. The dynamic gelling process was measured through rheological measurements. The microstructure was examined by lyophilizing to get porous scaffolds. Biological assessment was performed through CCK-8 assays by using synovium-derived mesenchymal cells (SMSCs) at 1, 3, 7 and 14 days. In vivo evaluation for application in cartilage tissue engineering was performed 8 weeks after subcutaneous injection of SMSC-loaded Odex/Mgel hydrogels combined with TGF-ß3 in the dorsa of nude mice. According to the results, a fast forming hydrogel was obtained by simply modifying dextran and gelatin. Moreover, the Odex/Mgel hydrogel exhibited good biocompatibility in cultures of SMSCs and a homogeneous distribution of live cells was achieved inside the hydrogels. After 8 weeks, newly formed cartilage was achieved in the dorsa of nude mice; no inflammatory reaction was observed and high production of GAGs was shown. The method provides a strategy for the design and fabrication of fast in situ forming hydrogels. The Odex/Mgel hydrogel could be used for the regeneration of cartilage in tissue engineering.

Stat3 upregulates leucine-rich repeat-containing g protein-coupled receptor 4 expression in osteosarcoma cells.

The activation of signal transducer and activator of transcription 3 (Stat3) signaling is the common hallmark in various human cancers including osteosarcoma. In the present study, according to PCR-based microarrays using cDNA prepared from interleukin-6 (IL-6) treated osteosarcoma cells, we found that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) was a transcriptional target of Stat3. Overexpression of Stat3 promoted LGR4 expression, while its deficiency using small interfering RNA (siRNA) reduced LGR4 expression. Furthermore, we identified a Stat3 binding motif located at -556 to -549 bp in the LGR4 promoter that is able to interact with Stat3. Thus, our results suggest a previously unknown Stat3-LGR4 molecular network, which may control osteosarcoma development and progression.