Effective methods for extracting extracellular polymeric substances from Shewanella oneidensis MR-1.

Extracellular polymeric substances (EPS) play crucial roles in bio-aggregate formation and survival of bacterial cells. To develop an effective but harmless method for EPS extraction from Shewanella oneidensis MR-1, five extraction methods, i.e. centrifugation (control), heating (40, 45, 50, and 60 °C), and treatments with H2SO4, ethylenediaminetetraacetic acid (EDTA) and NaOH, were examined, respectively. Results from scanning electron microscope and flow cytometric analyses indicate that MR-1 cells were severely broken by H2SO4, NaOH and heating temperature ≥45 °C. Proteins and polysaccharides in EPS extracted by heating at 40 °C were 7.12 and 1.60 mg g-1 dry cell, respectively. Although EDTA treatment had a relatively lower yield of EPS (proteins and polysaccharides yields of 5.15 and 1.30 mg g-1 dry cell, respectively), cell lysis was barely found after EPS extraction. Three peaks were identified from the three-dimensional excitation-emission matrix spectrum of each EPS sample, suggesting the presence of protein-like substances. Furthermore, the peak intensity was in good accordance with protein concentration measured by the chemical analysis. In short, heating (40 °C) and EDTA treatments were found the most suitable methods for EPS extraction considering the cell lysis and EPS content, composition and functional groups together.

Extraosseous cemento-ossifying fibroma beneath the left buccal mucosa: a case report.

Cemento-ossifying fibroma (COF) is a benign mesenchymal odontogenic tumor that commonly occurs in the tooth-bearing areas of the maxilla and mandible. This study reports a COF case located under the left buccal mucosa. The classification and differential diagnosis of this COF case were discussed based on the diagnosis and treatment of this case and previous literature.

Comparison of PEG precipitation and ultrafiltration treatment for serum macroprolactin in Chinese patients with hyperprolactinemia.

BACKGROUND: Macroprolactinemia is a common cause of hyperprolactinemia (HPRL), with an average worldwide incidence of 18.9 %. This study aimed to explore the feasibility of ultrafiltration (UF) and polyethylene glycol (PEG) precipitation for macroprolactin screening, as well as the incidence and clinical characteristics of Chinese patients with macroprolactinemia. METHODS: In this study, 94 patients with HPRL and 206 healthy individuals were included. Gel filtration chromatography (GFC), PEG precipitation, and UF were used to screen for macroprolactin, and chemiluminescence was used to determine the prolactin levels. RESULTS: The detected incidence of macroprolactinemia in the patients with HPRL was 7.45% (7/94, GFC) and 5.32% (5/94, PEG precipitation). Patients with macroprolactinemia usually present with atypical clinical symptoms, moderately increased prolactin levels, and negative or microadenoma-positive pituitary images. In addition, the recovery of monomeric prolactin by PEG precipitation and UF was significantly correlated to that of GFC (r PEG = 0.493, P < 0.001; r UF = 0.226, P = 0.014), with a higher correlation coefficient between PEG precipitation and GFC. Furthermore, PEG precipitation had a smaller variation (95% confidence interval [CI]: -35.77% to 18.34%) than UF in monomeric prolactin recovery and substantial diagnostic consistency with GFC (Cohen's kappa coefficient = 0.647). The proportion of monomeric prolactin in patients with HPRL did not change significantly between the two visits within one year (P > 0.05). CONCLUSION: The incidence of macroprolactinemia in Chinese patients with HPRL is low in the present study. Based on our analysis, we recommend that only patients who are clinically suspected of having macroprolactinemia should be screened using PEG precipitation.

[Preparation of ibuprofen/EC-PVP sustained-release composite particles by supercritical CO2 anti-solvent technology].

Ibuprofen/ethyl-cellulose (EC)-polyvinylpyrrolidone (PVP) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading as the main evaluation index, orthogonal experimental design was used to optimize the preparation process of EC-PVP/ibuprofen composite particles. The experiments such as encapsulation efficiency, particle size distribution, electron microscope analysis, infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 40 degrees C, crystallization pressure 12 MPa, PVP concentration 4 mgmL(-1), and CO2 velocity 3.5 Lmin(-1). Under the optimal conditions, the drug loading and encapsulation efficiency of ibuprofen/EC-PVP composite particles were 12.14% and 52.21%, and the average particle size of the particles was 27.621 microm. IR and DSC analysis showed that PVP might complex with EC. The experiments of in vitro dissolution showed that ibuprofen/EC-PVP composite particles had good sustained-release effect. Experiment results showed that, ibuprofen/EC-PVP sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Assembly Transformation Jointly Driven by the LAP Enzyme and GSH Boosting Theranostic Capability for Effective Tumor Therapy.

Developing intelligent and morphology-transformable nanomaterials that can spatiotemporally undergo stimulus-responsive size transformation holds great promise for improving the tumor delivery efficiency of drugs in vivo. Here, we report a smart size-transformable theranostic probe Ce6-Leu consisting of a leucine amino peptidase (LAP) and glutathione (GSH) dual-responsive moiety, an 1,2-aminothiol group, and a clinically used photosensitizer Ce6. This probe tends to self-assemble into uniform nanoparticles with an initial size of ∼80 nm in aqueous solution owing to the amphiphilic feature. Surprisingly, taking advantage of the biocompatible CBT-Cys condensation reaction, the large nanoprobes can be transformed into tiny nanoparticles (∼23 nm) under the joint action of LAP and GSH in a tumor microenvironment, endowing them with great tumor accumulation and deep tissue penetration. Concomitantly, this LAP/GSH-driven disassembly and size shrinkage of Ce6-Leu can also activate the fluorescence/magnetic resonance signals and the photodynamic effect for enhanced multimodal imaging-guided photodynamic therapy of human liver HepG2 tumors in vivo. More excitingly, the Mn2+-chelating probe (Ce6-Leu@Mn2+) was demonstrated to have the capability to catalyze endogenous H2O2 to persistently release O2 at the hypoxic tumor site, as a consequence improving the oxygen supply to boost the radiotherapy effect. We thus believe that this LAP/GSH-driven size-transformable nanosystem would offer a novel advanced technology to improve the drug delivery efficiency for achieving precise tumor diagnosis and treatment.

Liquid hot water pretreatment to enhance the anaerobic digestion of wheat straw-effects of temperature and retention time.

Wheat straw is an abundant agricultural waste that is rich in lignocellulose. However, its waxy surface, highly crystallized structure, and limited surface area make it difficult to be hydrolyzed and used efficiently by microorganisms. Liquid hot water (LHW) pretreatment was studied to explore the feasibility of improving the methane yield of wheat straw in anaerobic digestion (AD). The results showed that the crosslinking structure of wheat straw was broken by LHW pretreatment. Some pores and cracks appeared on the surface of the pretreated wheat straw, increasing the microbial attachment sites. Under different hydrothermal temperatures (150-225 °C) and retention times (5-60 min), the degradation of hemicellulose ranged from 27.69 to 99.07%. The maximum methane yield (201.81 mL CH4/g volatile solids) was achieved after LHW pretreatment at 175 °C for 30 min, which was a 62.9% increase compared with non-treated straw. LHW at high temperatures such as 225 °C was not suitable for the AD of wheat straw. Methane yield results were fitted with the first-order and modified Gompertz equations to evaluate the hydrolysis rate and inhibitory effects of the pretreated materials in AD.

A biotin receptor-targeted silicon(IV) phthalocyanine for in vivo tumor imaging and photodynamic therapy.

Phthalocyanines (Pcs) are a kind of potential photosensitizers for fluorescence imaging and photodynamic therapy (PDT). However, the clinical application of Pcs is suffered from their poor solubility, high aggregation tendency and low tumor-specificity. To address these problems, two biotin moieties were linked to the axial positions of silicon(IV) phthalocyanine (SiPc) through hydrophilic polyethylene glycol (PEG) linkers to synthesize a new water-soluble and tumor-targeting photosensitizer (compound 1). The introduction of PEG linkers on SiPc markedly reduced the aggregation tendency of the conjugate. In vitro assays also proved that compound 1 could specifically accumulate in biotin receptor (BR) positive Hela cells through the BR-mediated internalization. Owing to the good characteristics of water-solubility and low aggregation, the bioactivity of compound 1 was examined in the xenograft tumor model. In vivo imaging and tissue distribution studies showed that compound 1 selectively accumulated in the tumor tissue, with tolerable signals found in other organs of the tumor-bearing mice. Furthermore, compound 1 could significantly depress tumor progression in vivo under irradiation. After 14 days of the treatment, the tumor volumes were even smaller than the beginning size. All these results reveal that compound 1 is a promising candidate, with low aggregation tendency, high tumor-specificity and water-solubility, for in vivo tumor diagnosis and PDT treatment.

Photo-Powered Artificial Organelles for ATP Generation and Life-Sustainment.

Adenosine triphosphate (ATP) is the most important immediate energy source for driving intracellular biochemical reactions in nearly all life forms. Controllable generation of ATP in life is still an unrealized goal. Here, thylakoid fragments are recombined with lipid molecules to synthesize a synthetic/biological hybrid proteoliposome, named highly efficient life-support intracellular opto-driven system (HELIOS) for the generation of ATP. With red light irradiation, HELIOS can improve the intracellular ATP concentration to 1.38-2.45 times in various cell lines. Moreover, it is noticed that HELIOS-mediated ATP generation can comprehensively promote cell functions such as protein synthesis and insulin secretion. At organ and individual levels, it is also proved that HELIOS can rescue a mouse heart from myocardial infarction and sustain life of fasting zebrafish Danio rerio models. The photo-powered artificial organelle can deepen our understanding of metabolism and enable the development of optical therapy that targets intracellular energy supply.

Multilayered Graphene Hydrogel Membranes for Guided Bone Regeneration.

A multilayered graphene hydrogel (MGH) membrane is used as an excellent barrier membrane for guided bone regeneration. The unique multilayered nanostructure of the MGH membrane results in improved material properties, which benefits protein adsorption, cell adhesion, and apatite deposition, and allows higher quality and fast bone regeneration.

Ultrafast Dynamic Piezoresistive Response of Graphene-Based Cellular Elastomers.

Ultralight graphene-based cellular elastomers are found to exhibit nearly frequency-independent piezoresistive behaviors. Surpassing the mechanoreceptors in the human skin, these graphene elastomers can provide an instantaneous and high-fidelity electrical response to dynamic pressures ranging from quasi-static up to 2000 Hz, and are capable of detecting ultralow pressures as small as 0.082 Pa.

Therapeutic effects of nanogel containing triterpenoids isolated from Ganoderma lucidum (GLT) using therapeutic ultrasound (TUS) for frostbite in rats.

OBJECTIVE: The aim of this study was to evaluate the effect of therapeutic ultrasound (TUS) on dermal delivery and therapeutic effect for frostbite of nanogel containing triterpenoids isolated from Ganoderma lucidum (GLT). METHODS: GLT nanosuspension (GLT-NS) was prepared by high pressure homogenization and then suitably gelled to obtain GLT nanogel. The effects of TUS on GLT releasing from GLT nanogel and GLT permeation through the excised rat abdominal skin were evaluated. Moreover, a comparative study was also undertaken between different treatments of frostbite in rats: topical application of GLT nanogel (alone), TUS (alone) and GLT nanogel + TUS (plus). RESULTS: In the in vitro release study, TUS has no influence on drug release from the nanogel. Results of the in vitro transdermal study indicated that TUS significantly increased the cumulative amount of GLT permeating across and into the skin and reduced the lag time in comparison with passive diffusion (without TUS). As evidenced by the significant increase of wound healing area and the improvement in frostbite, TUS applied with simultaneous treatment method could improve the therapeutic effect of the GLT nanogel for frostbite. CONCLUSION: The present study revealed that the TUS can be effectively used to actively enhance topical delivery of GLT from nanogel and improve the therapeutic effect for frostbite in rats.

Mechanically robust, electrically conductive and stimuli-responsive binary network hydrogels enabled by superelastic graphene aerogels.

The architecture of the nanofiller phase in polymer nanocomposites matters! Polymer hydrogels that can combine stimuli-responsiveness with excellent electrically conductivity and mechanical strength can be fabricated by incorporation of the polymer into an ultralight and superelastic graphene aerogel to form a binary network.

The effect of polyethylene glycol recombinant human growth hormone on growth and glucose metabolism in hypophysectomized rats.

OBJECTIVE: To study the effect of polyethylene glycol recombinant human growth hormone on growth and glucose metabolism in hypophysectomized rats, and compare the effect of treatment between recombinant human growth hormone (rhGH) and polyethylene glycol rhGH (PEG-rhGH). METHODS: Hypophysectomy was performed in juvenile rats to build the animal model of GH deficiency. The hypophysectomized animals were randomly assigned into three groups and treated with saline (negative control, n=20), rhGH (n=20) and PEG-rhGH (n=20). A sham operation was performed to set up the normal control (n=20). Body weight, body length and tail length were recorded every 2days for a 14-day treatment and bone growth was measured at the end of therapy. Glucose infusion rate (GIR) determined by euglycemic hyperinsulinemic clamp was used to evaluate insulin sensitivity after GH treatment. We also examined plasma glucose and serum insulin levels RESULTS: Compared with the negative control, the body weight, body length, tail length and bone growth increased significantly in hypophesectomized rats treated by GH (P<0.01). Although the weight gain in the first 10days was higher in the PEG-rhGH group than in the rhGH group (P<0.05), the growth promoting effect was similar between rhGH and PEG-rhGH (P>0.05). Neither rhGH nor PEG-rhGH impaired glucose tolerance of rats after hypophesectomy. Compared with negative controls, according to decreased serum insulin, reduced insulin expression in pancreatic cells and increased GIR in the clamp, both rhGH and PEG-rhGH groups had improved insulin sensitivity within 14 days (P<0.01). However, with prolonged treatment, the GIR in the rhGH-treated rats decreased significantly (P<0.05); while PEG-rhGH did not interfere with GIR, even after a doubled dose (P>0.05). CONCLUSIONS: PEG-rhGH had the same linear growth promoting efficacy as unmodified rhGH. The short-term GH replacement could improve insulin sensitivity in hypophysectomized rats, especially after PEGylation.

[Preparation and biocompatibility evaluation of osteochondral composite scaffold].

OBJECTIVE: To prepare osteochondral composite scaffold and study its biocompatibility in vitro. METHODS: The composite material of nano-HAP/collagen I was prepared, and the osteochondral scaffold was manufactured by combining nano-HAP, collagen I, and PLGA as the bone section and sodium hyaluronate and PLGA as the chondral section. The diameter, chemical composition and crystallinity of the nano-HAP/collagen I composite particles were assessed with TEM, FTIR and XRD, and the biocompatibility and cytotoxicity of the scaffold were evaluated using MTT assay by co-culturing bone marrow stem cells and the scaffold. RESULTS AND CONCLUSION: The osteochondral composite scaffold has good microstructure without obvious cytotoxicity, possesses good biocompatibility with bone marrow stem cells and is suitable as an osteochondral scaffold material.

Molecular dynamics study of binding energies, mechanical properties, and detonation performances of bicyclo-HMX-based PBXs.

To investigate the effect of polymer binders on the monoexplosive, molecular dynamics simulations were performed to study the binding energies, mechanical properties, and detonation performances of the bicyclo-HMX-based polymer-bonded explosives (PBXs). The results show that the binding energies on different crystalline surfaces of bicyclo-HMX decrease in the order of (010)>(100)>(001). On each crystalline surface, binding properties of different polymers with the same chain segment are different from each other, while those of the polymers in the same content decrease in the sequence of PVDF>F(2311)>F(2314) approximately PCTFE. The mechanical properties of a dozen of model systems (elastic coefficients, various moduli, Cauchy pressure, and Poisson's ratio) have been obtained. It is found that mechanical properties are effectively improved by adding small amounts of fluorine polymers, and the overall effect of fluorine polymers on three crystalline surfaces of bicyclo-HMX changes in the order of (010)>(001) approximately (100). In comparison with the base explosive, detonation performances of the PBXs decrease slightly, but they are still superior to TNT. These suggestions may be useful for the formulation design of bicyclo-HMX-based PBXs.

The preparation and properties of monodisperse core-shell silica magnetic microspheres.

The monodisperse core-shell silica magnetic microspheres (MMS) were synthesized by sol-gel method gelling in the emulsion. Optical microscope (OM), field emission scanning electron microscope (FESEM), nitrogen adsorption and desorption Brunauer Emmett Teller Procedure (BET) isotherms and Barrett-Joyner-Halenda (BJH) pore size distribution measurements, X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and vibrating sample magnetometer (VSM) were used to characterize the appearance, size distribution, phase, specific surface area, chemical composition and magnetic property of silica MMS. The results showed that silica MMS prepared through sol-gel method with acid-alkali two-step catalyze and gelling in emulsion exhibited the superior core-shell structure and size distribution of the microspheres concentrated in about 20 mum. The main phase of microspheres was amorphous silica and spinel ferroferric oxide. Meanwhile, the microspheres remained the superparamagnetic behavior and could be used as biomaterials.