Microbiota in the apical root canal system of tooth with apical periodontitis.

BACKGROUND: Apical periodontitis (AP) is essentially an inflammatory disease of microbial etiology primarily caused by infection of the pulp and root canal system. Variation of the bacterial communities caused by AP, as well as their changes responding to dental therapy, are of utmost importance to understand the pathogensis of the apical periodontitis and establishing effective antimicrobial therapeutic strategies. This study aims to uncover the composition and diversity of microbiota associated to the root apex to identify the relevant bacteria highly involved in AP, with the consideration of root apex samples from the infected teeth (with/without root canal treatment), healthy teeth as well as the healthy oral. METHODS: Four groups of specimens are considered, the apical part of root from diseased teeth with and without root canal treatment, and wisdom teeth extracted to avoid being impacted (tooth healthy control), as well as an additional healthy oral control from biofilm of the buccal mucosa. DNA was extracted from these specimens and the microbiome was examined through focusing on the V3-V4 hypervariable region of the 16S rRNA gene using sequencing on Illumina MiSeq platform. Composition and diversity of the bacterial community were tested for individual samples, and between-group comparisons were done through differential analysis to identify the significant changes. RESULTS: We observed reduced community richness and diversity in microbiota samples from diseased teeth compared to healthy controls. Through differential analysis between AP teeth and healthy teeth, we identified 49 OTUs significantly down-regulated as well as 40 up-regulated OTUs for AP. CONCLUSION: This study provides a global view of the microbial community of the AP associated cohorts, and revealed that AP involved not only bacteria accumulated with a high abundance, but also those significantly reduced ones due to microbial infection.

Evaluation of Biodegradable Alloy Fe30Mn0.6N in Rabbit Femur and Cartilage through Detecting Osteogenesis and Autophagy.

Biodegradable iron alloy implants have become one of the most ideal possible candidates because of their biocompatibility and comprehensive mechanical properties. Iron alloy's impact on chondrocytes is still unknown, though. This investigation looked at the biocompatibility and degradation of the Fe30Mn0.6N alloy as well as how it affected bone formation and chondrocyte autophagy. In vivo implantation of Fe30Mn0.6N and Ti6Al4V rods into rabbit femoral cartilage and femoral shaft was carried out to evaluate the degradation of the alloy and the cartilage and bone response at different intervals. After 8 weeks of implantation, the cross-sectional area of the Fe30Mn0.6N alloys lowered by 50.79 ± 9.59%. More Ca and P element deposition was found on the surface Fe30Mn0.6N rods by using energy dispersive spectroscopy (EDS) and scanning electron microscopy (P < 0.05). After 2, 4, and 8 weeks of implantation, no evident inflammatory infiltration was seen in peri-implant cartilage and bone tissue of Fe30Mn0.6N and Ti6Al4V alloys. Also, implantation of Fe30Mn0.6N alloy promoted autophagy in cartilage by detecting expression of LC3-II compared with Ti6Al4V after implantation (P < 0.05). Fe30Mn0.6N alloy also stimulated early osteogenesis at the peri-implant interface compared with Ti6Al4V after implantation (P < 0.05). In the in vitro test, we found that low concentrations of Fe30Mn0.6N extracts had no influence on cell viability. 15% and 30% extracts of Fe30Mn0.6N could upregulate autophagy compared to the control group by detecting beclin-1, LC3, Atg3, and P62 on the basis of WB and IHC (P < 0.05). Also, the PI3K-AKT-mTOR signaling pathway mediated in the upregulation of autophagy of chondrocytes resulting in exposure to extract of Fe30Mn0.6N alloy. It is concluded that Fe30Mn0.6N showed degradability and biocompatibility in vivo and upregulated autophagy activity in chondrocytes.

[Effect of Twin-block in adolescents with mandibular retrusion and normal anterior overjet].

PURPOSE: To investigate the therapeutic effect of modified fixed Twin-block on patients whose mandible was retruded and anterior overjet was normal. METHODS: Thirty-six adolescents with mandibular retrusion and normal anterior overjet were selected. The goal of occlusal reconstruction was to move the soft tissue pogonion forward to the zero meridian(0°). Fixed Twin-block combined with the mini-implants on the mandibular buccal shelf was used to promote mandibular growth. After 12 months, the appliances were removed step by step to observe the stability of the jaw relationship. Fixed orthodontic treatment was performed to achieve ideal occlusion and coordinated profile. SPSS 13.0 software package was used for Student's t test. RESULTS: The length of mandibular body increased significantly which facilitated the forward movement of the soft tissue pogonion, and the profile changed from convex to straight. Comparison of the results before and after Twin-block treatment showed that Co-Gn, SNB, U1-SN, U6-0°, U1-0°, U1-L1, anterior overbite, anterior overjet, Pog's-0°, L1-0° and lower anterior facial height changed significantly (P＜0.05). Comparison of the results before and after fixed orthodontic treatment showed that PP-MP, SN-MP, U6-0°, IMPA, L1-0°,U1-SN, U1-L1, anterior overbite and overjet changed significantly(P＜0.05). CONCLUSIONS: Modified fixed Twin-block combined with mini-implants on the mandibular buccal shelf can effectively stimulate the mandibular growth and improve the lateral profile of patients with mandibular retrusion and normal overjet.

Gold/SH-functionalized nanographene oxide/polyamidamine/poly(ethylene glycol) nanocomposites for enhanced non-enzymatic hydrogen peroxide detection.

Hydrogen peroxide (H2O2) is an important mediator in biological medicine, disease diagnosis and environmental analyses and therefore it is essential to develop a detection approach for H2O2 in physical environments. Herein, we designed and prepared a series of AuNP-containing nanocomposites (AuNPs@NGO-PEG, AuNPs@G1-PAMAM-NGO-PEG and AuNPs@G3-PAMAM-NGO-PEG) for enhanced non-enzymatic H2O2 detection. We firstly demonstrated functionalized nanographene oxide (NGO) based materials, which combined advantages of biocompatible poly(ethylene glycol) (PEG), hyperbranched polyamidamine (PAMAM) dendrimer and thiol active site, as compatible platforms. Gold nanoparticles (AuNPs) were then aptly in situ grown on these functionalized NGO based materials via the reduction of HAuCl4 under mild conditions, i.e. AuNPs@NGO-PEG, AuNPs@G1-PAMAM-NGO-PEG and AuNPs@G3-PAMAM-NGO-PEG nanocomposites, which possess stable and uniform AuNPs standing on the functionalized NGO sheets. For H2O2 detection, these nanocomposites were cast on a glassy carbon electrode (GCE) conveniently, i.e. GCE/AuNPs@NGO-PEG, GCE/AuNPs@G1-PAMAM-NGO-PEG and GCE/AuNPs@G3-PAMAM-NGO-PEG. It is evident that these GCEs could be applied as efficient non-enzymatic H2O2 detectors resulting from the corresponding cyclic voltammetric curves and typical ready-state amperometric curves. GCE/AuNPs@G1-PAMAM-NGO-PEG exhibited the fastest electron transfer rate among these modified GCEs. We envisage that these GCEs could provide efficient sensors for H2O2 detection and a new strategy for sensor design.

Changes in tetracycline partitioning and bacteria/phage-comediated ARGs in microplastic-contaminated greenhouse soil facilitated by sophorolipid.

The emerging mixed contamination of antibiotics and microplastics in greenhouse soil has made the control of antibiotic resistant gene (ARG) transmission a novel challenge. In this work, surfactant sophorolipid was applied to enhance the dissipation of tetracycline (TC) and tet genes in the presence of microplastics in greenhouse soil. During 49days of incubation, soil bacteria and phages were both found to be the crucial reservoirs of ARGs. Meanwhile, microplastic's presence significantly inhibited the dissipation of TC and ARGs in the soil. However, sophorolipid application was proved to outweigh the negative impact caused by microplastic existence, and lead to the highest dissipation of soil TC and ARGs. Significant positive correlation was detected between the dissipation rate of water-soluble and exchangeable TC content and bacteria/phage co-mediated ARG levels. This also held true between the two fractions of soil TC and the ratio of ARG level in the bacteria to that in the phages (BARGs/PARGs). The opposite impacts of microplastic presence and sophorolipid amendment on the TC/ARG dissipation found in this work provides new information for understanding ARG transmission between bacteria and phages in the mixed contaminated greenhouse soil.

Quantitative Analysis of the Enhanced Permeation and Retention (EPR) Effect.

Tumor vasculature is characterized by a variety of abnormalities including irregular architecture, poor lymphatic drainage, and the upregulation of factors that increase the paracellular permeability. The increased permeability is important in mediating the uptake of an intravenously administered drug in a solid tumor and is known as the enhanced permeation and retention (EPR) effect. Studies in animal models have demonstrated a cut-off size of 500 nm - 1 µm for molecules or nanoparticles to extravasate into a tumor, however, surprisingly little is known about the kinetics of the EPR effect. Here we present a pharmacokinetic model to quantitatively assess the influence of the EPR effect on the uptake of a drug into a solid tumor. We use pharmacokinetic data for Doxil and doxorubicin from human clinical trials to illustrate how the EPR effect influences tumor uptake. This model provides a quantitative framework to guide preclinical trials of new chemotherapies and ultimately to develop design rules that can increase targeting efficiency and decrease unwanted side effects in normal tissue.

Defined nanoscale chemistry influences delivery of peptido-toxins for cancer therapy.

We present an in-silico-to-in-vitro approach to develop well-defined, self-assembled, rigid-cored polymeric (Polybee) nano-architecture for controlled delivery of a key component of bee venom, melittin. A competitive formulation with lipid-encapsulated (Lipobee) rigid cored micelle is also synthesized. In a series of sequential experiments, we show how nanoscale chemistry influences the delivery of venom toxins for cancer regression and help evade systemic disintegrity and cellular noxiousness. A relatively weaker association of melittin in the case of lipid-based nanoparticles is compared to the polymeric particles revealed by energy minimization and docking studies, which are supported by biophysical studies. For the first time, the authors' experiment results indicate that melittin can play a significant role in DNA association-dissociation processes, which may be a plausible route for their anticancer activity.

Point-of-service, quantitative analysis of ascorbic acid in aqueous humor for evaluating anterior globe integrity.

Limited training, high cost, and low equipment mobility leads to inaccuracies in decision making and is concerning with serious ocular injuries such as suspected ruptured globe or post-operative infections. Here, we present a novel point-of-service (POS) quantitative ascorbic acid (AA) assay with use of the OcuCheck Biosensor. The present work describes the development and clinical testing of the paper-based biosensor that measures the changes in electrical resistance of the enzyme-plated interdigitated electrodes to quantify the level of AA present in ocular fluid. We have demonstrated the proof-of-concept of the biosensor testing 16 clinical samples collected from aqueous humor of patients undergoing therapeutic anterior chamber paracentesis. Comparing with gold standard colorimetric assay for AA concentration, OcuCheck showed accuracy of >80%, sensitivity of >88% and specificity of >71%. At present, there are no FDA-approved POS tests that can directly measures AA concentration levels in ocular fluid. We envisage that the device can be realized as a handheld, battery powered instrument that will have high impact on glaucoma care and point-of-care diagnostics of penetrating ocular globe injuries.

[Analysis of the outcomes of squamous cell carcinoma of maxillary sinus with 3 different comprehensive treatments].

PURPOSE: To study the medium or long-term survival rates of different methods used in the treatment of advanced squamous cell carcinoma of the maxillary sinus (SCMS). METHODS: Patients were treated by one of the following methods: 231 patients were treated with induction chemotherapy, followed by radical resection and radiotherapy (CSR); 128 patients were treated with preoperative irradiation (RS), and 87 patients underwent adjuvant radiotherapy (RSR). A total of 446 cases of SCMS from June 1985 to December 2008 were managed with unscheduled application of the above 3 kinds of treatment options. The dose of 231 patients with CSR and 128 patients with RS was 60-70 Gy/30-35 times/5-7 week and 40-50 gy/20-25 times/4-5 week, respectively. Dose in RSR accounted for half of that in CSR. The number of cases undergoing total resection of maxilla, subtotal resection of maxilla and extended excision of maxilla were 299, 111 and 36, respectively (13 cases had orbital exenteration). The number of patients with therapeutic radical neck dissection, functional neck dissection and supraomohyoid neck dissection were 49, 73 and 56, respectively. The data was analyzed with SPSS16.0 software package. RESULTS: Five-year survival rate in 446 cases was 45.96% (205/446), and 220 patients died of tumors, among which 84.09% (185/220) of death were due to local recurrences. The 5-year survival rate of CSR, RS, and RSR were 45.88% (106/23), 46.09% (59/128) and 45.97% (40/87), respectively; Totally 83.33% of CSR, 85.71% of RS and 83.72% of RSR died of local recurrences. There was no significant difference in the survival rates among CSR, RS and RSR. CONCLUSIONS: Unscheduled comprehensive treatment have a higher 5-year survival rate in this advanced SCMS. Elective neck irradiation and neck dissection are necessary for medium or advanced squamous cell carcinoma of maxillary sinus.

Morphology and properties of poly vinyl alcohol (PVA) scaffolds: impact of process variables.

Successful engineering of functional biological substitutes requires scaffolds with three-dimensional interconnected porous structure, controllable rate of biodegradation, and ideal mechanical strength. In this study, we report the development and characterization of micro-porous PVA scaffolds fabricated by freeze drying method. The impact of molecular weight of PVA, surfactant concentration, foaming time, and stirring speed on pore characteristics, mechanical properties, swelling ratio, and rate of degradation of the scaffolds was characterized. Results show that a foaming time of 60s, a stirring speed of 1,000 rpm, and a surfactant concentration of 5% yielded scaffolds with rigid structure but with interconnected pores. Study also demonstrated that increased foaming time increased porosity and swelling ratio and reduced the rigidity of the samples.

Biomimetic apatite-coated porous PVA scaffolds promote the growth of breast cancer cells.

Recapitulating the native environment of bone tissue is essential to develop in vitro models of breast cancer bone metastasis. The bone is a composite material consisting of organic matrix and inorganic mineral phase, primarily hydroxyapatite. In this study, we report the mineralization of porous poly vinyl alcohol (PVA) scaffolds upon incubation in modified Hanks' Balanced Salt Solution (HBSS) for 14 days. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the deposited minerals have composition similar to hydroxyapatite. The study demonstrated that the rate of nucleation and growth of minerals was faster on surfaces of less porous scaffolds. However, upon prolonged incubation, formation of mineral layer was observed on the surface of all the scaffolds. In addition, the study also demonstrated that 3D mineralization only occurred for scaffolds with highly interconnected porous networks. The mineralization of the scaffolds promoted the adsorption of serum proteins and consequently, the adhesion and proliferation of breast cancer cells.

Tenax extraction for exploring rate-limiting factors in methyl-ß-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy soil.

The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information on what is the rate-limiting factor in bioremediation process is of vital importance in the decision in what measures can be taken to assist the biodegradation efficacy. In the present study, four different microcosms were set to study the effect of methyl-ß-cyclodextrin (MCD) and nitrate addition (N) on PAHs biodegradation under anaerobic conditions in a red paddy soil. Meanwhile, sequential Tenax extraction combined with a first-three-compartment model was employed to evaluate the rate-limiting factors in MCD enhanced anaerobic biodegradation of PAHs. Microcosms with both 1% (w/w) MCD and 20mM N addition produced maximum biodegradation of total PAHs of up to 61.7%. It appears rate-limiting factors vary with microcosms: low activity of degrading microorganisms is the vital rate-limiting factor for control and MCD addition treatments (CK and M treatments); and lack of bioaccessible PAHs is the main rate-limiting factor for nitrate addition treatments (N and MN treatments). These results have practical implications for site risk assessment and cleanup strategies.

[Preparation and characterization of polyvinyl alcohol microsphere pre-coated dynamic membranes].

To alleviate membrane fouling and reduce the price of membrane module, polyvinyl alcohol microsphere pre-coated dynamic membranes (PVA-MS/PCDMs) were investigated detailedly. It was prepared when the polyvinyl alcohol microsphere of the pre-coated reagent deposited on the surface and entered the pores of porous substrate common filter cloth which was low-cost by means of circulatory filtration. The morphology and structure of PVA-MS/PCDMs were examined using scanning electron microscope (SEM), and approximate maximal separated aperture, water contact angle, pure water permeation resistance and relative Zeta potential of the membrance surface were also determined. The results showed that pure water permeation resistance of PVA-MS/PCDMs was between 0.64 x 10(10) m(-1) and 3.84 x 10(10) m(-1) and the approximate maximal separated aperture reached microfiltration level. The hydrophilicity of PVA-MS/PCDMs increased with increasing PVA-MS pre-coated mass. The relative Zeta potential of the PVA-MS/PCDMs, which were measured using 0.01 mol x L(-1) KCl solution, pH 8.0 +/- 0.2 and at 20 degrees C, reached a peak value of -36.4 mV with pre-coated mass of 15.7 g x m(-2) PVA-MS on the membrance surface. In addition, evolutions of PVA-MS/PCDMs flux versus time were investigated using a 4 hours short-term filtration experiment at 9.5 kPa in an SMBR and the permeability coefficient of PVA-MS/PCDMs were measured by the extracellular polymeric substances (EPS) diffusion experiments. Results indicated that the PVA-MS/PCDMs presented dramatically high anti-fouling characteristics when the pre-coated mass of PVA-MS was 23.9-61.9 g x m(-2).

[Preparation and characterization of cross-linked polyvinyl alcohol microspheres as a novel precoating reagent in dynamic membrane].

In order to modify the membrane surface by adsorbing a precoated layer, cross-linked polyvinyl alcohol microspheres were prepared via an emulsion polymerization that PVA cross linked with glutaraldehyde which was extracted by anhydrous aether. Effects of concentration of PVA solution, the volume ratio of aqueous phase to oil phase, the selection of surface active agent (SAA) and its concentration on the stabilization of emulsion were studied. When the concentration of PVA solution was 2.7%, the volume ratio of PVA solution/n-heptane was 40:60 and the concentration of span-80 was 1.30 g/dL, the prepared microspheres contented our needs. The size of microspheres diminished with the stirring speed increasing under the condition of enough span-80. It became smaller with the accretion of an aimed cross-linking degree which has little affection on surface charge. The contact angle of PVA microspheres with distilled water showed that these microspheres were hydrophilic. Morphology of PVA microspheres were observed by SEM. The FTIR results suggested that functional groups varied with the change of aimed cross-linking degrees.

[Anti-fouling characteristics of the novel precoating reagent in dynamic membrane bioreactor].

Further research was made on precoating reagents in dynamic membrane process, in which novel precoating reagent-polyvinyl alcohol microsphere (PVA-MS) was prepared through emulsive polymerization of PVA and glutaraldehyde (GA). Furthermore, polymerization mechanism and anti-fouling characteristics through adsorption of membrane major fouling substances EPS upon PVA-MS were studied. The results showed that hemiacetals reaction played a major role in emulsive polymerization process, as the quantity of hydroxyl on PVA was decreased a little, PVA-MS surface behaved good hydrophilic, and the adsorption of protein and amylose upon PVA microsphere was stable and low, which was 0.543 mg x g(-1) and 0.694 mg x g(-1) respectively. In addition, PVA-MS surface behaved electronic negativity, which acted electrostatic repulsion to active sludge floc. Upon this characteristics and data, it was concluded that membrane fouling was delayed in microscopy structure. Diameter of PVA-MS in precoating liquid was about 1.14 microm, and Zeta-potential of precoating liquid with different precoating reagent concentration was less than - 39 mV, which made PVA microsphere diffused and stable from each other, then sedimentate rapidly on porous support membrane surface and internal wall of hole path. Besides, the morphology of PVA-MS and dynamic membrane formed from PVA-MS on support membrane were observed through SEM.

[Experimental study on application of the boundary layer theory for determining steady aeration intensity of precoated dynamic membrane bioreactor].

The rheological behaviour of the low sludge concentration liquor in MBR was investigated and made a conclusion that this liquor approximated to the Newtonian fluid while the concentration of the sludge was less than 8000 mg x L(-1). Furthermore, when the laminar flow boundary layer thickness on the surface of flat membrane came up to the thickness of precoated dynamic membrane (PDM), the steady aeration intensity was calculated by using the boundary layer theory in the Newtonian hydrodynamics. In order to ensure the stability of the pre-coated dynamic membrane bioreactor (PDMBR), oxygen supply aeration intensity was chosen to supply the best dissolved oxygen (3-5 mg x L(-1) in the initial stages and gradually increased to the steady aeration intensity. The results indicated that this mode could enhance the stability of PDM. In the experiment period (31 d), effluent COD was less than 12.48 mg x L(-1) and its average removal rate was 97.49%, NH4+ -N was less than 5.27 mg x L(-1) and its average removal rate was 76.13%, while the operational pressure just increased to 27 kPa. During the last period of the experiment, the stability of the PDMBR was studied when the aeration intensity was more than the steady aeration intensity and it was found that the precoated layer had been brushed off from the surface of common filter cloth, so this phenomenon proved that using the boundary layer theory could determine steady aeration intensity of PDMBR.