GOx-assisted synthesis of pillar[5]arene based supramolecular polymeric nanoparticles for targeted/synergistic chemo-chemodynamic cancer therapy.

BACKGROUND: Cancer is the most serious world's health problems on the global level and various strategies have been developed for cancer therapy. Pillar[5]arene-based supramolecular therapeutic nano-platform (SP/GOx NPs) was constructed successfully via orthogonal dynamic covalent bonds and intermolecular H-bonds with the assistance of glucose oxidase (GOx) and exhibited efficient targeted/synergistic chemo-chemodynamic cancer therapy. METHODS: The morphology of SP/GOx NPs was characterized by DLS, TEM, SEM and EDS mapping. The cancer therapy efficinecy was investigated both in vivo and in vitro. RESULTS: SP/GOx NPs can load drug molecules (Dox) and modify target molecule (FA-Py) on its surface conveniently. When the resultant FA-Py/SP/GOx/Dox NPs enters blood circulation, FA-Py will target it to cancer cells efficiently, where GOx can catalyst the overexpressed glucose to generate H2O2. Subsequently, the generated H2O2 in cancer cells catalyzed by ferrocene unit to form •OH, which can kill cancer cells. Furthermore, the loaded Dox molecules released under acid microenvironment, which can further achieve chemo-therapy. CONCLUSION: All the experiments showed that the excellent antitumor performance of FA-Py/SP/GOx/Dox NPs, which provided an new method for pillar[5]arene-based supramolecular polymer for biomedical applications.

Extended-Duration MK-8591-Eluting Implant as a Candidate for HIV Treatment and Prevention.

Regimen adherence remains a major hurdle to the success of daily oral drug regimens for the treatment and prevention of human immunodeficiency virus (HIV) infection. Long-acting drug formulations requiring less-frequent dosing offer an opportunity to improve adherence and allow for more forgiving options with regard to missed doses. The administration of long-acting formulations in a clinical setting enables health care providers to directly track adherence. MK-8591 (4'-ethynyl-2-fluoro-2'-deoxyadenosine [EFdA]) is an investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI) drug candidate under investigation as part of a regimen for HIV treatment, with potential utility as a single agent for preexposure prophylaxis (PrEP). The active triphosphate of MK-8591 (MK-8591-TP) exhibits protracted intracellular persistence and, together with the potency of MK-8591, supports its consideration for extended-duration dosing. Toward this end, drug-eluting implant devices were designed to provide prolonged MK-8591 release in vitro and in vivo Implants, administered subcutaneously, were studied in rodents and nonhuman primates to establish MK-8591 pharmacokinetics and intracellular levels of MK-8591-TP. These data were evaluated against pharmacokinetic and pharmacodynamic models, as well as data generated in phase 1a (Ph1a) and Ph1b clinical studies with once-weekly oral administration of MK-8591. After a single administration in animals, MK-8591 implants achieved clinically relevant drug exposures and sustained drug release, with plasma levels maintained for greater than 6 months that correspond to efficacious MK-8591-TP levels, resulting in a 1.6-log reduction in viral load. Additional studies of MK-8591 implants for HIV treatment and prevention are warranted.

Solvothermal transformation of a calcium oleate precursor into large-sized highly ordered arrays of ultralong hydroxyapatite microtubes.

Hydroxyapatite (HAP), a well-known member of the calcium phosphate family, is the major inorganic component of bones and teeth in vertebrates. The highly ordered arrays of HAP structures are of great significance for hard tissue repair and for understanding the formation mechanisms of bones and teeth. However, the synthesis of highly ordered HAP structure arrays remains a great challenge. In this work, inspired by the ordered structure of tooth enamel, we have successfully synthesized three-dimensional bulk materials with large sizes (millimeter scale) that are made of highly ordered arrays of ultralong HAP microtubes (HOAUHMs) by solvothermal transformation of calcium oleate precursor. The core-shell-structured oblate sphere consists of a core that is composed of HAP nanorods and a shell that consists of highly ordered HAP microtube arrays. The prepared HOAUHMs are large: 6.0 mm in diameter and up to 1.4 mm in thickness. With increasing solvothermal reaction time, the HOAUHMs grow larger; the microtubes become more uniform and more ordered. This work provides a new synthetic method for synthesizing highly ordered arrays of uniform HAP ultralong microtubes that are promising for biomedical applications.

Hydroxyapatite hierarchically nanostructured porous hollow microspheres: rapid, sustainable microwave-hydrothermal synthesis by using creatine phosphate as an organic phosphorus source and application in drug delivery and protein adsorption.

Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave-assisted hydrothermal method. The as-obtained products are characterized by powder X-ray diffraction (XRD), Fourier-transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer-Emmett-Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8-1.5 µm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m(2) g(-1) and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant-free and environmentally friendly. The as-prepared HAP porous hollow microspheres show a relatively high drug-loading capacity and protein-adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption.

Wnt3a-Loaded Hydroxyapatite Nanowire@Mesoporous Silica Core-Shell Nanocomposite Promotes the Regeneration of Dentin-Pulp Complex via Angiogenesis, Oxidative Stress Resistance, and Odontogenic Induction of Stem Cells.

Pulp exposure often leads to pulp necrosis, root fractures, and ultimate tooth loss. The repair of the exposure site with pulp capping treatment is of great significance to preserving pulp vitality, but its efficacy is impaired by the low bioactivity of capping materials and cell injuries from the local accumulation of oxidative stress. This study develops a Wnt3a-loaded hydroxyapatite nanowire@mesoporous silica (Wnt3a-HANW@MpSi) core-shell nanocomposite for pulp capping treatments. The ultralong and highly flexible hydroxyapatite nanowires provide the framework for the composites, and the mesoporous silica shell endows the composite with the capacity of efficiently loading/releasing Wnt3a and Si ions. Under in vitro investigation, Wnt3a-HANW@MpSi not only promotes the oxidative stress resistance of dental pulp stem cells (DPSCs), enhances their migration and odontogenic differentiation, but also exhibits superior properties of angiogenesis in vitro. Revealed by the transcriptome analysis, the underlying mechanisms of odontogenic enhancement by Wnt3a-HANW@MpSi are closely related to multiple biological processes and signaling pathways toward pulp/dentin regeneration. Furthermore, an animal model of subcutaneous transplantation demonstrates the significant reinforcement of the formation of dentin-pulp complex-like tissues and blood vessels by Wnt3a-HANW@MpSi in vivo. These results indicate the promising potential of Wnt3a-HANW@MpSi in treatments of dental pulp exposure.

Glucose Oxidase Integrated Porphyrinic Covalent Organic Polymers for Combined Photodynamic/Chemodynamic/Starvation Therapy in Cancer Treatment.

The anticancer effect of photodynamic therapy (PDT) is usually impeded by the hypoxia microenvironment in solid tumors; thus, it requires integration with other treatment tactics to achieve an optimal anticancer efficacy. Porphyrin-containing nanotherapeutic agents are broadly used for PDT in tumor treatment. However, chemodynamic therapy (CDT) of porphyrin-based namomaterials has been rarely reported. Here, a novel nanoscale porphyrin-containing covalent organic polymer (PCOP) was designed by the cross-linking of 5,10,15,20-tetrakis(4-aminophenyl)porphyrin with 1,1'-ferrocenedicarboxylic acid at room temperature. After glucose oxidase (GOx) was loaded, the obtained nanotherapeutic agent of PCOPs@GOx presented an augmented synergy of PDT, CDT, and energy starvation to suppress tumor growth upon near-infrared light irradiation. In vitro and in vivo outcomes demonstrated that this multifunctional nanoplatform not only realized excellent tumor inhibition but also provided a new tactic for designing chemodynamic/photodynamic/starvation combined therapy in one material.

Polydopamine-drug conjugate nanocomposites based on ZIF-8 for targeted cancer photothermal-chemotherapy.

Stimuli-responsive prodrug-based nanoplatform with synergistic antitumor activity is of central importance to the development of promising nanomedicines for cancer therapy. Here, we describe a polydopamine-drug conjugate nanocomposite (ZP-PDA-DOX) with targeted cancer photothermal-chemotherapy (PTT-CT), which constructed by a gradual copolymerization of dopamine (DA) and pH-sensitive dopamine-derived prodrug (DA-DOX) into the porous channels of zeolite imidazolate frameworks-8 (ZIF-8), followed by PEGylation with amino-terminated folic acid-polyethylene glycol (NH2 -PEG-FA) to acquire the high biocompatibility, specificity, and excellent tumor-targeting property. The incorporation of polydopamine strengthened the stability and dispersion of ZIF-8, and also conferred photothermal conversion effect. In the tumor acidic microenvironment, the acid-labile hydrazone linker of DA-DOX and ZIF-8 promptly degraded to release activated DOX. Moreover, the generated hyperthermia due to the high photothermal conversion efficiency of PDA component could accelerate drug release, and simultaneously thermally ablate tumor tissue to maximize the DOX-induced CT, which could also assist PTT to eradicate tumor cells. This study provides a promising strategy for targeted cancer PTT-CT with synergistic anti-tumor effect.

Nursing effect of Nasoscopically assisted nasogastri tube and nasojejunal tube placement.

OBJECTIVE: To investigate the nursing effect of nasoscopically assisted nasogastri tube and nasojejunal tube placement. METHODS: 94 patients who need to place nasogastric tube and nasojejunal tube to establish enteral nutrition were randomly divided into two groups: the observation group (n=49) and control group (n=45). The patients in the observation group received nasogastric tube placement and jejunal nutrition tube placement, and the patients in the control group received general gastroscope and placed gastric tube and jejunal nutrition tube through mouth. Success rate of catheterization, catheter pain score, satisfaction score, vital signs, completion time of catheterization, and complication were collected. RESULTS: the fluctuation of vital signs in control group was significantly higher than that in observation group. There was statistical significance between two groups in vital signs after intervention (P<0.05), mainly manifested in the heart rate, breathing and pulse pressure difference. On the other hand, there was no statistical significance between two groups in pulse oxygen after nursing intervention (P>0.05). The catheter pain score is obviously improved in the observation group compared with control group after intervention. The improvement score of satisfaction in the observation group was 91.47±7.65 points, and that in the control group was 83.64±5.24 points. The completion time of catheterization was improved in the observation group compared with control group. There was statistical significance between two groups in satisfaction score and completion time of catheterization (P<0.05). The rate of abdominal distention and diarrhea in the control group was higher than that in the observation group (P<0.05). CONCLUSION: Nasoscopically assisted nasogastri tube and nasojejunal tube placement has the advantages of simple and fast, short operation time, high success rate and few complications. It is the first choice of intubation method for enteral nutrition support treatment.

Biodegradable nanocomposite of glycerol citrate polyester and ultralong hydroxyapatite nanowires with improved mechanical properties and low acidity.

Glycerol citrate polyester based on the condensation of glycerol and citric acid has a great potential in biomedical applications owing to biocompatible monomers and biodegradation properties. However, the applications of glycerol citrate polyester are impaired by its poor mechanical properties and high acidity caused by citric acid produced in the degradation process. In this work, a new kind of nanocomposite has been developed using ultralong hydroxyapatite (HAP) nanowires as the "skeleton", and strongly bound glycerol citrate polyester as the "muscle". The ultralong HAP nanowires interweave with each other to form a three-dimensional nanoporous network, and glycerol citrate polyester is homogeneously distributed in the nanoporous network. Owing to the reinforcement of ultralong HAP nanowires, the mechanical properties of the as-prepared nanocomposite are significantly improved compared with the pure glycerol citrate polyester, and the tensile strength even reaches to the level of human cortical bones. Furthermore, the acidity of the aqueous solution after degradation is neutralized by the reaction between citric acid and ultralong HAP nanowires, and the pH value can be stabilized. The as-prepared nanocomposite can solve some problems of the pure glycerol citrate polyester, and shows promising applications in the biomedical field.

Nitrobenzene reduction using nanoscale zero-valent iron supported by polystyrene microspheres with different surface functional groups.

Three polystyrene (PS) resin microspheres supported nanoscale zero-valent iron (nZVI), i.e., nZVI@PS, nZVI@PS-Cl, and nZVI@PS-N, were prepared and characterized by FT-IR, XPS, SEM, EDS, and weighing method. The functional groups on the carriers showed obvious influence on the loading quantity, the micro morphology, and the reduction efficiency of these supported nZVI. The best hybrid reducer was nZVI@PS-N. The load quantity of nZVI was 0.2476 g/g, and some of them were dispersed and the others remained as particles (≤ 50 nm). At optimal reaction conditions, i.e., initial solution pH = 3, 25 °C, 100 r/min stirring, 99% nitrobenzene (NB) in 250 mL 123.1 mg/L NB solution could be totally reduced into AN by 1.31 g fresh nZVI@PS-N within 20 min. The excellent reduction efficiency and fast degradation rate of nZVI@PS-N were mainly attributed to the synergistic effects between the good adsorption property of its carrier and the high reduction activity of nZVI particles. NZVI@PS-N was reproducible and recycled, and 90.6% degradation ratio of NB was till obtained at its seventh recycle. The results showed that nZVI@PS-N had high potential practical application value in the reductive degradation and emergency rescue of nitrobenzene pollutant.

Effectiveness of a Web-Based Personalized Rheumatoid Arthritis Risk Tool With or Without a Health Educator for Knowledge of Rheumatoid Arthritis Risk Factors.

OBJECTIVE: To assess knowledge of rheumatoid arthritis (RA) risk factors among unaffected first-degree relatives (FDRs) and to study whether a personalized RA education tool increases risk factor knowledge. METHODS: We performed a randomized controlled trial assessing RA educational interventions among 238 FDRs. The web-based Personalized Risk Estimator for RA (PRE-RA) tool displayed personalized RA risk results (genetics, autoantibodies, demographics, and behaviors) and educated about risk factors. Subjects were randomly assigned to a Comparison arm (standard RA education; n = 80), a PRE-RA arm (PRE-RA alone; n = 78), or a PRE-RA Plus arm (PRE-RA and a one-on-one session with a trained health educator; n = 80). The RA Knowledge Score (RAKS), the number of 8 established RA risk factors identified as related to RA, was calculated at baseline and post-education (immediate/6 weeks/6 months/12 months). We compared RAKS and its components at each post-education point by randomization arm. RESULTS: At baseline before education, few FDRs identified behavioral RA risk factors (15.6% for dental health, 31.9% for smoking, 47.5% for overweight/obesity, and 54.2% for diet). After education, RAKS increased in all arms, higher in PRE-RA and PRE-RA Plus than Comparison at all post-education points (P < 0.05). PRE-RA subjects were more likely to identify risk factors than those who received standard education (proportion agreeing that smoking is a risk factor at 6 weeks: 83.1% in the PRE-RA Plus arm, 71.8% in the PRE-RA arm, and 43.1% in the Comparison arm; P < 0.05 for PRE-RA versus Comparison). CONCLUSION: Despite being both familiar with RA and at increased risk, FDRs had low knowledge about RA risk factors. A web-based personalized RA education tool successfully increased RA risk factor knowledge.

Disclosure of Personalized Rheumatoid Arthritis Risk Using Genetics, Biomarkers, and Lifestyle Factors to Motivate Health Behavior Improvements: A Randomized Controlled Trial.

OBJECTIVE: To determine the effect of disclosure of rheumatoid arthritis (RA) risk personalized with genetics, biomarkers, and lifestyle factors on health behavior intentions. METHODS: We performed a randomized controlled trial among first-degree relatives without RA. Subjects assigned to the Personalized Risk Estimator for Rheumatoid Arthritis (PRE-RA) group received the web-based PRE-RA tool for RA risk factor education and disclosure of personalized RA risk estimates, including genotype/autoantibody results and behaviors (n = 158). Subjects assigned to the comparison arm received standard RA education (n = 80). The primary outcome was readiness for change based on the trans-theoretical model, using validated contemplation ladder scales. Increased motivation to improve RA risk-related behaviors (smoking, diet, exercise, or dental hygiene) was defined as an increase in any ladder score compared to baseline, assessed immediately, 6 weeks, and 6 months post-intervention. Subjects reported behavior change at each visit. We performed intent-to-treat analyses using generalized estimating equations for the binary outcome. RESULTS: Subjects randomized to PRE-RA were more likely to increase ladder scores over post-intervention assessments (relative risk 1.23, 95% confidence interval [95% CI] 1.01, 1.51) than those randomized to nonpersonalized education. At 6 months, 63.9% of PRE-RA subjects and 50.0% of comparison subjects increased motivation to improve behaviors (age-adjusted difference 15.8%; 95% CI 2.8%, 28.8%). Compared to nonpersonalized education, more PRE-RA subjects increased fish intake (45.0% versus 22.1%; P = 0.005), brushed more frequently (40.7% versus 22.9%; P = 0.01), flossed more frequently (55.7% versus 34.8%; P = 0.004), and quit smoking (62.5% versus 0.0% among 11 smokers; P = 0.18). CONCLUSION: Disclosure of RA risk personalized with genotype/biomarker results and behaviors increased motivation to improve RA risk-related behaviors. Personalized medicine approaches may motivate health behavior improvements for those at risk for RA and provide rationale for larger studies evaluating effects of behavior changes on clinical outcomes, such as RA-related autoantibody production or RA development.

Dopamine-modified highly porous hydroxyapatite microtube networks with efficient near-infrared photothermal effect, enhanced protein adsorption and mineralization performance.

In the last decade, the porous hydroxyapatite (HAP) scaffold has been investigated for the application in tissue engineering owing to its good bioactivity and high biocompatibility. In this work, the dopamine-modified highly porous hydroxyapatite microtube three-dimensional (3-D) networks with efficient near-infrared photothermal effect, enhanced protein adsorption and mineralization performance have been prepared through a facile method. The dopamine-modified highly porous HAP networks exhibit ultrahigh porosity (90.6%), uniform pore distribution, interconnected pore structure and outstanding mechanical properties. After being modified with dopamine, the protein adsorption amount, cell attachment performance, and mineralization ability of the dopamine-modified highly porous HAP network can be greatly improved. In addition, the as-prepared dopamine-modified highly porous HAP networks exhibit good biocompatibility, excellent near-infrared photothermal effect, and good mechanical properties. The experimental results indicate that the dopamine-modified highly porous HAP networks are promising for various applications.

Effect of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits.

OBJECTIVE: To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits. METHODS: Twenty-four Japanese white rabbits underwent laminectomy (including the attached ligaments) at L(2 ) and L(5). After laminectomy at L(5), polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L(2), nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts. RESULTS: The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group, which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group. CONCLUSIONS: Polylactic acid glue can effectively reduce epidural cicatrization and adhesion.

[Interfacial Property of Amphiphilic Copolymer Blending PVDF UF Membrane and Protein Anti-fouling].

The phase transformation kinetic process of amphiphilic copolymer polyoxyethylene/polyoxypropylene/polyoxyethylene[PEO-PPO-PEO(F127)] blending polyvinylidene fluoride (PVDF) casting solution in an aqueous gel bath was investigated. The influences of F127 content on the PEO enrichment rate of PVDF membrane surface, membrane morphology and structural parameters were investigated by a total reflection fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM) and other analytical techniques. F127/PVDF blending membrane fouling behavior of bovine serum albumin (BSA) was evaluated by the static adsorption capacity, normalized filtration decay rate and membrane fouling resistance model. The results showed that the membrane delayed phase separation process increased, the membrane surface, internal pore size and porosity increased and the surface roughness increased with increasing F127 addition, and the increment of PEO enrichment rate on the membrane surface became stable when the F127 content reached 15%. F127 blending membranes with F127 contents ranging from 15% to 25% had a higher flux and BSA rejection, lower static adsorption capacity, slower flux decay rate, lower irreversible fouling index and smaller pore blocking resistance and cake layer resistance distribution coefficient, which showed a good anti-fouling property.

Porous microspheres of amorphous calcium phosphate: block copolymer templated microwave-assisted hydrothermal synthesis and application in drug delivery.

Amorphous calcium phosphate (ACP) microspheres with a porous and hollow structure have been prepared using an aqueous solution containing CaCl2 as a calcium source, adenosine triphosphate disodium salt (Na2ATP) as a phosphorus source in the presence of a block copolymer methoxyl poly(ethylene glycol)-block-poly(D,L-lactide) (mPEG-PLA) by the microwave-assisted hydrothermal method. The effects of microwave hydrothermal temperature and the concentrations of CaCl2 and Na2ATP on the crystal phase and morphology of the product are investigated. The as-prepared ACP porous hollow microspheres have a relatively high specific surface area of 232.9 m(2) g(-1) and an average pore size of 9.9 nm. A typical anticancer drug, docetaxel, is used to evaluate the drug loading ability and drug release behavior of ACP porous hollow microspheres in phosphate buffered saline (PBS) with different pH values of 4.5 and 7.4. The experiments reveal that the ACP porous hollow microspheres have a high drug loading capacity and favorable pH-responsive drug release property, and the ACP porous hollow microsphere drug delivery system shows a high ability to damage tumor cells. It is expected that the as-prepared ACP porous hollow microspheres are promising for the applications in various biomedical fields such as drug delivery.

Application of molecularly imprinted polymers in wastewater treatment: a review.

Molecularly imprinted polymers are synthetic polymers possessing specific cavities designed for target molecules. They are prepared by copolymerization of a cross-linking agent with the complex formed from a template and monomers that have functional groups specifically interacting with the template through covalent or noncovalent bonds. Subsequent removal of the imprint template leaves specific cavities whose shape, size, and functional groups are complementary to the template molecule. Because of their predetermined selectivity, molecularly imprinted polymers (MIPs) can be used as ideal materials in wastewater treatment. Especially, MIP-based composites offer a wide range of potentialities in wastewater treatment. This paper reviews the latest applications of MIPs in wastewater treatment, highlights the development of MIP-based composites in wastewater, and offers suggestions for future success in the field of MIPs.

Overexpression of AT14A confers tolerance to drought stress-induced oxidative damage in suspension cultured cells of Arabidopsis thaliana.

Drought stress can affect interaction between plant cell plasma membrane and cell wall. Arabidopsis AT14A, an integrin-like protein, mediates the cell wall-plasma membrane-cytoskeleton continuum (WMC continuum). To gain further insight into the function of AT14A, the role of AT14A in response to drought stress simulated by polyethylene glycol (PEG-6000) in Arabidopsis suspension cultures was investigated. The expression of this gene was induced by PEG-6000 resulting from reverse transcription-PCR, which was further confirmed by the expression data from publically available microarray datasets. Compared to the wild-type cells, overexpression of AT14A (AT14A-OE) in Arabidopsis cultures exhibited a greater ability to adapt to water deficit, as evidenced by higher biomass accumulation and cell survival rate. Furthermore, AT14A-OE cells showed a higher tolerance to PEG-induced oxidative damage, as reflected by less H2O2 content, lipid peroxidation (malondialdehyde (MDA) content), and ion leakage, which was further verified by maintaining high levels of activities of antioxidant defense enzymes such as ascorbate peroxidase and guaiacol peroxidase and soluble protein. Taken together, our results suggest that overexpression of AT14A improves drought stress tolerance and that AT14A is involved in suppressing oxidative damage under drought stress in part via regulation of antioxidant enzyme activities.

[Application of enzyme histochemistry in evaluation of in vitro and in vivo biocompatibility of HA/TCP].

In order to explore the possibility of applying enzyme histochemistry in biocompatibility evaluation, we investigated the effect of biomaterials on the activities of intracellular enzymes in this experiment. It was found that there was no obvious difference in morphology between osteoblasts co-cultured with HA/TCP and with Ti-alloy. However, transient down-regulation of NADH, SDH, LDH and CCO of the osteoblasts co-cultured with HA/TCP was detected by enzyme histochemistry, but these enzymes of osteoblasts the co-cultured with Ti-alloy were not down-regulated. It was indicated that something extracted from HA/TCP injured the co-cultured osteoblasts slightly. Similar early acute inflammatory reactions were observed after HA/TCP and Ti-alloy were separately implanted into the dorsal muscle of rabbit. There was also no obvious difference between the tissue response to HA/TCP and that to Ti-alloy. Activities of enzymes in tissues around implanted materials were down-regulated at the early injury period and recovered gradually within 30 days post-operation. But the mild toxicity of extracts from HA/TCP was demonstrated by the fact that the recovery period of HA/TCP group was longer than that of Ti-alloy group. It was proved that enzyme histochemistry is more sensitive than tissue morphology analysis in detecting the cell or tissue responses to biomaterials. Therefore, it is possible to use enzyme histochemistry in biocompatibility evaluation.

Amorphous calcium phosphate nanospheres/polylactide composite coated tantalum scaffold: facile preparation, fast biomineralization and subchondral bone defect repair application.

Calcium phosphate (CaP) materials are widely used in various biomedical areas such as drug/gene delivery and bone repair/tissue engineering. In this study, amorphous CaP nanospheres synthesized by a simple co-precipitation method are used to prepare the CaP-polylactide (CaP-PLA) composite. Then, the as-prepared CaP-PLA composite is used to coat tantalum (Ta) plates and porous scaffolds. Compared with bare Ta plate, CaP-PLA coated Ta plates show a high performance of surface biomineralization in simulated body fluid (SBF). In addition, the hydrophilicity of the CaP-PLA coated Ta plates is significantly improved. CaP-PLA coated Ta plates with bovine serum albumin (BSA) are prepared and used for the investigation of BSA release in vitro. The experimental results indicate a sustained BSA release property and simultaneous biomineralization of the as-prepared BSA-containing CaP-PLA coated Ta plates. Furthermore, CaP-PLA coated Ta scaffolds are favorable for the human osteoblast-like MG63 cells adhesion and spreading. The vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-containing CaP-PLA coated porous Ta scaffolds are used for the study of rabbit subchondral bone defect repair, covering with autogeneic periosteums. The as-prepared CaP-PLA composite coated Ta scaffolds are useful to guide the bone regeneration in vivo.