Gut Microbiota in Children with Hand Foot and Mouth Disease on 16S rRNA Gene Sequencing.

Hand foot and mouth disease (HFMD) is a contagious and seasonal viral disease in children. The gut microbiota of HFMD children is not clear now. The study aimed to explore the gut microbiota of HFMD children. The 16S rRNA gene of the gut microbiota of ten HFMD patients and ten healthy children were sequenced on the NovaSeq and PacBio platforms respectively. There were significant differences in gut microbiota between the patients and healthy children. The diversity and abundance of gut microbiota in HFMD patients were lower than that in healthy children. The species Roseburia inulinivorans and Romboutsia timonensis were more abundant in healthy children than those in HFMD patients, which suggests that the two species may be used as probiotics for adjusting the gut microbiota of HFMD patients. Meanwhile, the results of 16S rRNA gene sequences from the two platforms were different. The NovaSeq platform identified more microbiota and has the characteristics of high throughput, short time and low price. However, the NovaSeq platform has low resolution at the species level. The PacBio platform has high resolution based on its long reads length, which is more suitable for species-level analysis. But, the shortcomings of the high price and low throughput of PacBio still need to be overcome. With the development of sequencing technology, the reduction in sequencing price and the increase in throughput will promote the third-generation sequencing technology used in the study of gut microbes.

Laccase3-based extracellular domain provides possible positional information for directing Casparian strip formation in Arabidopsis.

The Casparian strip (CS) is a tight junction-like structure formed by lignin impregnation on the walls of endodermal cells in plant roots. The CS membrane domain (CSDM), demarked by the CASP proteins, is important for orienting lignification enzymes. Here, we report that an endodermis-expressed multicopper oxidase, LACCASE3 (LAC3) in Arabidopsis, locates to the interface between lignin domains and the cell wall during early CS development prior to CASP1 localizing to CSDM and eventually flanks the mature CS. Pharmacological perturbation of LAC3 causes dispersed localization of CASP1 and compensatory ectopic lignification. These results support the existence of a LAC3-based CS wall domain which coordinates with CSDM to provide bidirectional positional information that guides precise CS lignification.

Enhanced antitumor efficacy in colon cancer using EGF functionalized PLGA nanoparticles loaded with 5-Fluorouracil and perfluorocarbon.

BACKGROUND: Tumor recurrence and metastasis occur at a high rate in patients with colon cancer. Identification of effective strategies for the treatment of colon cancer is critical. Recently, poly (lactic-co-glycolic acid) (PLGA) has been shown to have potential as a broad therapeutic drug delivery system. We designed a dual-loaded nanoparticle drug delivery system to overcome the limitations of chemotherapeutic drugs used to treat colon cancer. METHODS: We developed epidermal growth factor (EGF) functionalized PLGA nanoparticles (NPs) co-loaded with 5-fluorouracil (5Fu) and perfluorocarbon (PFC) (EGF-PLGA@5Fu/PFC) for targeted treatment of colon cancer. CCK-8 assay, Hoechst33342 staining and flow cytometry were performed to investigate the functions of EGF-PLGA@5Fu/PFC NPs in SW620 cells. Beside, animal experiment, histological analysis and immunofluorescence staining were adopted to further confirm the role of EGF-PLGA@5Fu/PFC NPs in vivo. RESULTS: The findings showed that EGF-PLGA@5Fu /PFC NPs had an average size 200 nm and a 5Fu-loading efficiency of 7.29%. Furthermore, in vitro release was pH-sensitive. Targeted EGF-PLGA@5Fu/PFC NPs exhibited higher cellular uptake than non-targeted NPs into colon cancer cells. In addition, EGF-PLGA@5Fu/PFC NPs suppressed cell viability and induced apoptosis in SW620 cells to a greater extent than non-targeted NPs. In tumor xenografted mice, EGF-PLGA@5Fu/PFC NPs suppressed tumor growth more effectively than 5Fu, PLGA@5Fu or PLGA@5Fu/PFC NPs. Histopathological analysis further demonstrated that EGF-targeted NPs inhibited tumor growth to a greater extent than non-targeted or non-NP treatments. The improved therapeutic outcomes observed in this study were due to relief of tumor hypoxia by transport of oxygen by PFC to the tumors. CONCLUSION: We constructed a biocompatible nanodrug delivery system based on functionalized nanoparticles that provided a novel strategy for selective delivery of chemotherapy drugs to tumors.

Automatic tooth roots segmentation of cone beam computed tomography image sequences using U-net and RNN.

BACKGROUND: Automatic segmentation of individual tooth root is a key technology for the reconstruction of the three-dimensional dental model from Cone Beam Computed Tomography (CBCT) images, which is of great significance for the orthodontic, implant and other dental diagnosis and treatment planning. OBJECTIVES: Currently, tooth root segmentation is mainly done manually because of the similar gray of the tooth root and the alveolar bone from CBCT images. This study aims to explore the automatic tooth root segmentation algorithm of CBCT axial image sequence based on deep learning. METHODS: We proposed a new automatic tooth root segmentation method based on the deep learning U-net with AGs. Since CBCT sequence has a strong correlation between adjacent slices, a Recurrent neural network (RNN) was applied to extract the intra-slice and inter-slice contexts. To develop and test this new method for automatic segmentation of tooth roots using CBCT images, 24 sets of CBCT sequences containing 1160 images and 5 sets of CBCT sequences containing 361 images were used to train and test the network, respectively. RESULTS: Applying to the testing dataset, the segmentation accuracy measured by the intersection over union (IOU), dice similarity coefficient (DICE), average precision rate (APR), average recall rate (ARR), and average symmetrical surface distance (ASSD) are 0.914, 0.955, 95.8% , 95.3% , 0.145 mm, respectively. CONCLUSIONS: The study demonstrates that the new method combining attention U-net with RNN yields the promising results of automatic tooth roots segmentation, which has potential to help improve the segmentation efficiency and accuracy in future clinical practice.

[Analysis of clinical application characteristics of Xiyanping Injection in 194 873 cases in real world].

To analyze the clinincal application characteristics of Xiyanping Injection in real world. The data of the patients came from the hospital information systerm(HIS) of 29 tertiary hospitals in China from 2006 to 2016. It included three parts about basic information, Western medicine diagnosis information, and doctor advice information. The exploration was conducted for the characteristics of the patients and disease distribution as well as the therapeutic regimen. Apriori algorithm was adopted to establish the models, and Clementing 12.0 was used for a correlation analysis of the comprehensive therapeutic regimen of Xiyanping Injection. There were 194 873 cases in the study. The male to female ratio was 1.44∶1. The median age was 4 years old. The median daily dosage was 200 mg. 46.68% of the patients were administered with 250-500 mg, and 33.07% were 50-100 mg one day. 47.08% of the patients were administered for 4-7 d, and 32.65% of the patients were 1-3 d. In the doctor advice information, the most frequently types of Western medicine, traditional Chinese medicine were mucilagin, heat-clearing agent. Second generation cephalosporins, third generation cephalosporins, compound penicillin were the most common types of antibiotic. Interferon, nucleoside and nucleotide, human immunoglobulin were the most common types of antiviral drug. The mining association rules results were analyzed, finding the application of Xiyanping Injection in severe infectious diseases. To improve respiratory symptoms, Xiyanping Injection treaments were Budesonide + Ipratropium Bromide + Ambroxol. To severe pulmonary infection, the treaments were Dopamine + Ambroxine. To severe hand, foot and mouth disease, the treatments were Namefen + Mannitol. To pulmonary heart failure, the treatments were Dobutamine + Heparin. Based on the results of the real world HIS, we could provide clinical application the idea, and a reference for further excavation of the applicable diseases of Xiyanping Injection.

Radially Aligned Electrospun Fibers with Continuous Gradient of SDF1α for the Guidance of Neural Stem Cells.

Repair of spinal cord injury will require enhanced recruitment of endogenous neural stem cells (NSCs) from the central canal region to the lesion site to reestablish neural connectivity. The strategy toward this goal is to provide directional cues, e.g., alignment topography and biological gradients from the rostral and caudal ends toward the center. This study demonstrates a facile method for fabrication of continuous gradients of stromal-cell-derived factor-1α (SDF1α) embedded in the radially aligned electrospun collagen/poly (ε-caprolactone) mats. Gradients can be readily produced in a controllable and reproducible fashion by adjusting the collection time and collector size during electrospinning. To get a long-term gradient, the SDF1α is fused with a unique peptide of collagen-binding domain (CBD), which can bind to collagen specifically. Aligned CBD-SDF1α gradients show stable, sustained, and gradual release during 7 d. Further, the effect of aligned CBD-SDF1α gradients on the guidance of NSCs is investigated. It is found that the CBD-SDF1α gradient scaffolds direct and enhance NSC migration from the periphery to the center along the aligned electrospun fibers. Taken together, the tubular conduits based on radially aligned electrospun fibers with continuous SDF1α gradient show great potential for guiding nerve regeneration.

Characterization of degradation behaviors of PLA biodegradable plastics by infrared spectroscopy.

In this paper, the degradation behavior of two kinds of polylactic acid (PLA) biodegradable material products (pure PLA cup cover and modified PLA straw) was studied. It was found that under the composting environment specified in the International Standard, in the first 35 days, the degradation rate of the straw (with 50%-60% poly butylenes succinate (PBS)) was faster than that of the pure PLA cup cover, but in the later stage, the PLA cup cover exceeded the straw and disintegrated preferentially, and both could be degraded in about 70 days. After further analyzing the far-infrared (FIR, can also be called THz) and mid infrared (MIR) spectra of cup cover and straw, we observed that the material structure had not changed until disintegration, only the ester bond was hydrolyzed, the polymers became oligomers, which could be reflected in the change of the effective area of the characteristic peak at 7.15 THz (cup cover, labeled 1921) and 6.99 THz (straw, labeled 4386) in the THz spectrum. With the degradation, the effective area decreased continuously. Due to the strong absorption of the material in MIR band, most characteristic peaks were flattened and lost analytical value. The bivariate correlation of degradation time, biodegradation rate, total carbon dioxide release and the effective area of the characteristic peak at 7.15 THz (1921) and 6.99 THz (4386) in THz spectrum was analyzed by SPSS software. We discovered that the degradation time was significantly positively correlated with biodegradation rate and carbon dioxide release at the level of 0.01 and negatively correlated with the effective area of characteristic peak at the level of 0.05. The biodegradation rate was significantly negatively correlated with the effective area of characteristic peak at the level of 0.01. Taking the degradation time as the independent variable and the biodegradation rate, carbon dioxide release and effective area of characteristic peak as the dependent variables, we got that the THz spectrum could be used to describe the degradation behavior of PLA products as long as appropriate coefficient correction was made. In this way, we could separate from the laboratory environment, study the impact of environmental diversification on material degradation performance, and reduce the cost of material degradation performance identification. Using density functional theory (DFT), reduced density gradient (RDG) method and visualization software, the changes of weak interaction position and intensity in the molecule during the polymerization of lactic acid into PLA were further analyzed. We found that the vibration of ester bond corresponded to the characteristic peak with weak intensity in the spectrum, and the peak with large intensity mainly originated from the out-of-plane swing of O-H bond in the molecule.

Restoration of spinal cord biophysical microenvironment for enhancing tissue repair by injury-responsive smart hydrogel.

Spinal cord injury (SCI) represents a central nervous system disaster, resulting in the destruction of spinal cord structure and function and the formation of an adverse microenvironment at the SCI site. Various biomaterial-based therapeutic strategies have been developed to repair SCI by bridging spinal cord lesions. However, constructing a favorable biophysical microenvironment with biomaterials for spinal cord regeneration remains challenging because of the unmatched mechanical and electrical transmission properties with native spinal cords and the supra- or subtherapeutic dose release of biological molecules independent of SCI activity. Herein, we developed a new hydrogel with mechanical properties and conductivities comparable to those of native spinal cords by controlling gelatin and PPy concentrations. To endow the hydrogel with a biological function, glutathione (GSH) was conjugated on the hydrogel through gelatin-derived amine groups and GSH-derived sulfhydryl groups to prepare an MMP-responsive hydrogel with a recombinant protein, GST-TIMP-bFGF. The MMP-responsive conductive hydrogel could release bFGF on-demand in response to the SCI microenvironment and provide a favorable biophysical microenvironment with comparable mechanical and electrical properties to native spinal cords. In SCI model rats, the MMP-responsive bionic mechanical and conductive hydrogel could inhibit MMPs levels, promote axon regeneration and angiogenesis, and improve locomotion function recovery after SCI.

[Recombinant human bone morphogenetic protein 2/porous calcium phosphate cement/autologous bone and combination of platelet-rich plasma in repairing of large bone defects in rabbits by Masquelet technique].

Objective: To investigate the optimal mixing ratio of recombinant human bone morphogenetic protein 2 (rhBMP-2) with porous calcium phosphate cement (PCPC) and autologous bone as bone grafting material for the repair of large bone defects using Masquelet technique. The effect of platelet-rich plasma (PRP) on the healing of bone defects was evaluated under the optimal ratio of mixed bone. Methods: Fifty-four New Zealand White rabbits were taken to establish a 2 cm long bone defect model of the ulna and treated using the Masquelet technique. Two parts of the experiment were performed in the second phase of the Masquelet technique. First, 36 modeled experimental animals were randomly divided into 4 groups ( n=9) according to the mass ratio of autologous bone and rhBMP-2/PCPC. Group A: autologous bone (100%); group B: 25% autologous bone+75% rhBMP-2/PCPC; group C: 50% autologous bone+50% rhBMP-2/PCPC; group D: 75% autologous bone+25% rhBMP-2/PCPC. The animals were executed at 4, 8, and 12 weeks postoperatively for general observation, imaging observation, histological observation (HE staining), alkaline phosphatase (ALP) activity assay, and biomechanical assay (three-point bending test) were performed to assess the osteogenic ability and to determine the optimal mixing ratio. Then, 18 modeled experimental animals were randomly divided into 2 groups ( n=9). The control group was implanted with the optimal mixture ratio of autologous bone+rhBMP-2/PCPC, and the experimental group was implanted with the optimal mixture ratio of autologous bone+rhBMP-2/PCPC+autologous PRP. The same method was used to observe the above indexes at 4, 8, and 12 weeks postoperatively. Results: The bone healing process from callus formation to the cortical connection at the defected gap could be observed in each group after operation; new bone formation, bridging with the host bone, and bone remodeling to normal bone density were observed on imaging observation; new woven bone, new capillaries, bone marrow cavity, and other structures were observed on histological observation. The ALP activity of each group gradually increased with time ( P<0.05); the ALP activity of group A was significantly higher than that of the other 3 groups at each time point after operation, and of groups C and D than group B ( P<0.05); there was no significant difference between groups C and D ( P>0.05). Biomechanical assay showed that the maximum load in three-point bending test of each group increased gradually with time ( P<0.05), and the maximum loads of groups A and D were significantly higher than that of groups B and C at each time point after operation ( P<0.05), but there was no significant difference between groups A and D ( P>0.05). According to the above tests, the optimal mixing ratio was 75% autogenous bone+25% rhBMP-2/PCPC. The process of new bone formation in the experimental group and the control group was observed by gross observation, imaging examination, and histological observation, and the ability of bone formation in the experimental group was better than that in the control group. The ALP activity and maximum load increased gradually with time in both groups ( P<0.05); the ALP activity and maximum load in the experimental group were significantly higher than those in the control group at each time point after operation ( P<0.05), and the maximum load in the experimental group was also significantly higher than that in group A at 12 weeks after operation ( P<0.05). Conclusion: In the second phase of Masquelet technique, rhBMP-2/PCPC mixed with autologous bone to fill the bone defect can treat large bone defect of rabbit ulna, and it has the best osteogenic ability when the mixing ratio is 75% autologous bone+25% rhBMP-2/PCPC. The combination of PRP can improve the osteogenic ability of rhBMP-2/PCPC and autologous bone mixture.

Bioinspired Cellulose Foam with Excellent Water Wicking and Flux Properties Prepared Using Ice Template.

The application and functionalization of cellulose has been attracting increased attention in academic and industrial studies because of its wide range of sources, short renewable cycle, and low environmental impact. In order to enhance the application field of cellulose and decrease the environmental pollution for organic solvent associated with its preparation, cellulose foam with a vertically hierarchically porous structure similar to wood was designed and fabricated successfully from a cellulose aqueous solution using an ice templated in this study. The cellulose foam prepared using a 3 wt % concentration possessed a uniform vertical hierarchically porous structure, which could provide a pathway for the flow of water or air based on the capillary effect. The highest water wicking rate and flux were 7.8184 mm·s-1 and 29.49 mL·min-1·g-1, respectively, for the porous foam prepared using a 3 wt % concentration. The mechanical testing experiment showed that the porous structure did not reduce the amount of stress that the sample could endure before being damaged. The compression strength increased with increasing cellulose concentration in solution. Therefore, the hierarchical structure formed in the prepared cellulose foam effectively improved the water flux behavior and provided a structural basis for future applications of cellulose scaffolds.

Effect of poly (lactic acid) porous membrane prepared via phase inversion induced by water droplets on 3T3 cell behavior.

Phase inversion induced by water droplets has garnered attention in the field of polymer science as a novel method for preparing porous membranes. This study investigates the effect of the porous structure of poly (lactic acid) (PLA) membranes prepared through phase inversion induced by water droplets at four different temperatures (25, 50, 75, and 100 °C) on the morphology and proliferation of 3T3 cells. The surface properties of the PLA porous membrane, including pore size, pore size distribution, surface roughness, surface hydrophilicity, and cytocompatibility with 3T3 cells, were evaluated. The results indicated that the synthesized PLA membrane had two surfaces with different structures. The upper surface in contact with the water droplets during preparation contained uniformly distributed micropores, whereas the bottom surface was smooth and composed of small particles in contacted with the mold. The upper surface showed high cytocompatibility with 3T3 cells, and the 3T3 cells migrated and grew within the pores at 25 °C. In contrast, the bottom surface exhibited low biocompatibility with the 3T3 cells. Our study has wide-ranging implications and will improve the fabrication and implementation of 3D cultured scaffolds with excellent cytocompatibility.

Are cuproproteins part of the multi-protein framework for making the Casparian strip?

Casparian strip (CS) is a lignified structure localized on the cell wall between adjacent root endodermal cells and functions as an apoplastic diffusion barrier in the root. The polarly localized, lignin-based CS is an excellent system for studying peptide signaling and position recognition. In this short review, we summarize advances in the past decade on the molecular mechanism governing CS development. In addition to the multi-protein framework underlying the CS membrane domain, we discuss recently observed participation of cell wall located cuproproteins in CS formation. These new discoveries shed light on a potential CS wall domain that coordinates with the membrane domain to provide bidirectional positional information for guiding precise CS development.

Combined Therapeutic Effects of 131I-Labeled and 5Fu-Loaded Multifunctional Nanoparticles in Colorectal Cancer.

BACKGROUND: Owing to its combined effects, the co-delivery of different therapeutics is a promising option for the treatment of cancer. In the present study, tumor-targeting poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) nanoparticles were developed for the transportation of two molecules, namely chemotherapeutic drug 5-fluorouracil (5Fu) and radionuclide iodine-131 (131I), in a single platform. METHODS: The obtained nanoparticles (Cetuximab [Cet]-PEG-PLA-5Fu-131I) were spherical (diameter approximately 110 nm) and pH-sensitive. The targeting effect of nanoparticles via Cet was confirmed in colorectal cancer cells using a fluorescent assay. The combined effects of Cet-PEG-PLA-5Fu-131I on cell viability and apoptosis were evaluated in colorectal cancer cells by Cell Counting Kit-8 and flow cytometry assays. RESULTS: Blank nanoparticles (Cet-PEG-PLA) showed good biocompatibility, and Cet-PEG-PLA-5Fu-131I nanoparticles were the most effective in terms of inhibition of cell viability and induction of apoptosis compared with monotherapy using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-131I. In the xenograft mouse model, compared with using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-131I alone, Cet-PEG-PLA-5Fu-131I nanoparticles exhibited prolonged circulation in the blood and accumulation in the tumor, thus resulting in enhanced antitumor efficacy. Additionally, combined radio-chemotherapy with Cet-PEG-PLA-5Fu-131I nanoparticles was associated with smaller tumor sizes than monotherapy, revealing the superior antitumor effects of Cet-PEG-PLA-5Fu-131I nanoparticles. These effects were further evidenced by histological and immunohistochemical analyses. CONCLUSION: The multifunctional Cet-PEG-PLA-5Fu-131I nanoparticles are promising candidates for the co-delivery of 5Fu-mediated chemotherapy and 131I-mediated radiotherapy.

Effect of temperature on the morphology of poly (lactic acid) porous membrane prepared via phase inversion induced by water droplets.

Temperature is a critical parameter that can control the morphology of poly (lactic acid) (PLA) porous membranes prepared through phase inversion induced by water droplets. It determines the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent. In this work, in order to investigate the effect of temperature on the morphology, PLA porous membranes were prepared via phase inversion induced by water droplets at different temperatures. The morphologies of the prepared membranes were observed using scanning electron microscopy, and the volatilization rate of the solvent and the exchange rate between the solvent and nonsolvent were tested separately. The experimental data indicated that the volatilization rate of the solvent was faster than the exchange rate between the solvent and nonsolvent. A uniform porous structure was obtained for the PLA membrane, and the pore size decreased with the increase in temperature from 25 °C to 75 °C. This result indicated that a PLA porous membrane with desired pore size could be achieved by adjusting the ambient temperature.

Biocompatible and degradable Bletilla striata polysaccharide hemostasis sponges constructed from natural medicinal herb Bletilla striata.

Medicinal herb Bletilla striata as a traditional Chinese herb has been used to treat alimentary canal mucosal damage, ulcers, bruises, and burns for thousands of years. Despite numerous efforts directed at the development of Bletilla striata products, the challenge of preparing Bletilla striata hemostasis dressings while simultaneously maintaining portability and high hemostasis performance has not yet been addressed. Herein, we describe a Bletilla striata polysaccharide (BSP) sponge with hierarchical aligned porous channels formed via directional freeze technology. The microstructure and mechanical property of the BSP sponges could be controlled by modifying the BSP concentration. Notably, in vivo animal studies indicated that BSP sponges show high biocompatibility and degradation and possess excellent hemostasis capability. In addition, BSP sponges showed accelerated wound healing in comparison to commercial dressings. Thus, our study indicates that the constructed BSP sponges could find potential application in dressings for efficient wound healing.

A collagen microchannel scaffold carrying paclitaxel-liposomes induces neuronal differentiation of neural stem cells through Wnt/ß-catenin signaling for spinal cord injury repair.

Neural stem cells (NSCs) show potential for spinal cord injury (SCI) repair. However, the current challenge is to direct their differentiation into neurons in the lesion site. It has been demonstrated that transplanted NSCs primarily differentiated into astrocytes rather than neurons due to the adverse microenvironment. It was reported that microtubule-stabilizing agent paclitaxel (PTX) was able to reduce scarring and enhance intrinsic axon regeneration after SCI. In this study, the effect of PTX on NSC differentiation was studied. It was demonstrated for the first time that PTX could rescue myelin-inhibited neuronal differentiation of NSCs, and induced a higher neuronal differentiation as compared with that in normal microenvironment. Enhanced neuronal differentiation in normal microenvironment further validated that PTX was capable of inducing intrinsic neuronal differentiation of NSCs. Furthermore, a functional collagen scaffold was developed by loading PTX-encapsulated liposomes into a collagen microchannel scaffold, leading to a prolonged sustained release of PTX. When NSC-laden functional collagen scaffold was implanted into T8 complete transection site of rat spinal cord, the scaffold provided an instructive microenvironment for neuronal differentiation of NSCs, motor and sensory neuron regeneration, and axon extension. The neural regeneration eventually led to improvement in motor evoked potential and hindlimb locomotion recovery. Moreover, mRNA-Seq and western blotting results revealed that PTX-triggered neuronal differentiation occurred through Wnt/ß-catenin signaling pathway. Together, the collagen microchannel scaffold in combination with sustained release of therapeutic agents for inducing neuronal differentiation of NSCs is promising for SCI repair.

The effect of native silk fibroin powder on the physical properties and biocompatibility of biomedical polyurethane membrane.

Naturally derived fibers such as silk fibroin can potentially enhance the biocompatibility of currently used biomaterials. This study investigated the physical properties of native silk fibroin powder and its effect on the biocompatibility of biomedical polyurethane. Native silk fibroin powder with an average diameter of 3 µm was prepared on a purpose-built machine. A simple method of phase inversion was used to produce biomedical polyurethane/native silk fibroin powder hybrid membranes at different blend ratios by immersing a biomedical polyurethane/native silk fibroin powder solution in deionized water at room temperature. The physical properties of the membranes including morphology, hydrophilicity, roughness, porosity, and compressive modulus were characterized, and in vitro biocompatibility was evaluated by seeding the human umbilical vein endothelial cells on the top surface. Native silk fibroin powder had a concentration-dependent effect on the number and morphology of human umbilical vein endothelial cells growing on the membranes; cell number increased as native silk fibroin powder content in the biomedical polyurethane/native silk fibroin powder hybrid membrane was increased from 0% to 50%, and cell morphology changed from spindle-shaped to cobblestone-like as the native silk fibroin powder content was increased from 0% to 70%. The latter change was related to the physical characteristics of the membrane, including hydrophilicity, roughness, and mechanical properties. The in vivo biocompatibility of the native silk fibroin powder-modified biomedical polyurethane membrane was evaluated in a rat model; the histological analysis revealed no systemic toxicity. These results indicate that the biomedical polyurethane/native silk fibroin powder hybrid membrane has superior in vitro and in vivo biocompatibility relative to 100% biomedical polyurethane membranes and thus has potential applications in the fabrication of small-diameter vascular grafts and in tissue engineering.

[Efficacy of double-door laminoplasty combined with hydroxyapatite artificial bone grafting for cervical spinal stenotic myelopathy].

OBJECTIVE: To evaluate the effects of double-door laminoplasty and hydroxyapatite artificial bone grafting in the treatment of cervical spinal stenotic myelopathy. METHODS: Twelve cases of cervical spinal stenotic myelopathy underwent expansive double-door laminoplasty of the cervical spine and hydroxyapatite artificial bone grafting. The clinical outcome of the patients and the operative procedures were assessed. RESULTS: The 5-year follow-up showed significantly alleviated clinical symptoms and improved physical signs in all the patients except for 1 patient who responded poorly to the surgery. CONCLUSIONS: Expansive double-door laminoplasty of the cervical spine in combination with hydroxyapatite artificial bone grafting is safe and effective for treating cervical spinal stenotic myelopathy. Hydroxyapatite artificial bone possesses good biological compatibility and osteoconduction, and is applicable in the laminoplasty procedures as an ideal bone graft material.

Regulation of human mesenchymal stem cells differentiation into chondrocytes in extracellular matrix-based hydrogel scaffolds.

To induce human mesenchymal stem cells (hMSCs) to differentiate into chondrocytes in three-dimensional (3D) microenvironments, we developed porous hydrogel scaffolds using the cartilage extracellular matrix (ECM) components of chondroitin sulfate (CS) and collagen (COL). The turbidity and viscosity experiments indicated hydrogel could form through pH-triggered co-precipitation when pH=2-3. Enzyme-linked immunosorbent assay (ELISA) confirmed the hydrogel scaffolds could controllably release growth factors as envisaged. Transforming growth factor-ß (TGF-ß) was released to stimulate hMSCs differentiation into chondrocytes; and then collagen binding domain-basic fibroblast growth factor (CBD-bFGF) was released to improve the differentiation and preserve the chondrocyte phenotype. In in vitro cell culture experiments, the differentiation processes were compared in different microenvironments: 2D culture in culture plate as control, 3D culture in the fabricated scaffolds without growth factors (CC), the samples with CBD-bFGF (CC-C), the samples with TGF-ß (CC-T), the samples with CBD-bFGF/TGF-ß (CC-CT). Real-time polymerase chain reaction (RT-PCR) revealed the hMSC marker genes of CD44 and CD105 decreased; at the same time the chondrocyte marker genes of collagen type II and aggrecan increased, especially in the CC-CT sample. Immunostaining results further confirmed the hMSC marker protein of CD 44 disappeared and the chondrocyte marker protein of collagen type II emerged over time in the CC-CT sample. These results imply the ECM-based hydrogel scaffolds with growth factors can supply suitable 3D cell niches for hMSCs differentiation into chondrocytes and the differentiation process can be regulated by the controllably released growth factors.

Lymphatic-targeted cationic liposomes: a robust vaccine adjuvant for promoting long-term immunological memory.

Although retaining antigens at the injection site (the so-called "depot effect") is an important strategy for vaccine development, increasing evidence showed that lymphatic-targeted vaccine delivery with liposomes could be a promising approach for improving vaccine efficacy. However, it remains unclear whether antigen depot or lymphatic targeting would benefit long-term immunological memory, a major determinant of vaccine efficacy. In the present study, OVA antigen was encapsulated with DOTAP cationic liposomes (LP) or DOTAP-PEG-mannose liposomes (LP-Man) to generate depot or lymphatic-targeted liposome vaccines, respectively. The result of in vivo imaging showed that LP mostly accumulated near the injection site, whereas LP-Man not only effectively accumulated in draining lymph nodes (LNs) and the spleen, but also enhanced the uptake by resident antigen-presenting cells. Although LP vaccines with depot effect induced anti-OVA IgG more potently than LP-Man vaccines did on day 40 after priming, they failed to mount an effective B-cell memory response upon OVA re-challenge after three months. In contrast, lymphatic-targeted LP-Man vaccines elicited sustained antibody production and robust recall responses three months after priming, suggesting lymphatic targeting rather than antigen depot promoted the establishment of long-term memory responses. The enhanced long-term immunological memory by LP-Man was attributed to vigorous germinal center responses as well as increased Tfh cells and central memory CD4(+) T cells in the secondary lymphoid organs. Hence, lymphatic-targeted vaccine delivery with LP-Man could be an effective strategy to promote long-lasting immunological memory.