Antibiotic resistance of Riemerella anatipestifer and comparative analysis of antibiotic-resistance gene detection methods.

Riemerella anatipestifer is an important pathogen in waterfowl, and is generally multidrug resistant. This study assessed the current status of Riemerella anatipestifer antibiotic resistance and antibiotic-resistance genes (ARGs), compared the results of different detection methods, and evaluated a new method of studying the association between antibiotic resistance and ARGs in Riemerella anatipestifer. In this study, 51 strains of Riemerella anatipestifer were isolated from ducks on several farms, their resistance to 28 antibiotics was assessed, and the isolates were subjected to whole-genome sequencing. The number of ARGs carried by Riemerella anatipestifer was predicted, compared, and analyzed, and the consistency between ARGs and antibiotic-resistance phenotypes was assessed. The potential for loss of resistance genes during the sequencing and assembly of genome-wide framework map was assessed, and a new ARG detection method was pilot tested. The 51 strains of Riemerella anatipestifer were multidrug resistant (MDR) and had high level of resistance to aminoglycosides, trimethoprim, lincosamides, polypeptides, and macrolides. Based on the genome-wide framework map of the 51 strains, 3 local databases of ABRicate software and 1 online database of CARD website were used to detect ARGs, and a mean of 4 to 5 ARGs were identified per isolate. Although the detection results differed according to the database used, the general performance was consistent. The online website detected more types of ARGs than the ABRicate software. The association between ARGs and antibiotic-resistance phenotypes was assessed, and the ermF gene was identified as a possible key ARGs regulating macrolide resistance of Riemerella anatipestifer. The method used to investigate and detect Riemerella anatipestifer ARGs was convenient and rapid, and had strong accuracy and pertinence. The ARGs detection method reported here combined the advantages of PCR and genome detection, and could greatly reduce workload and detect ARGs more precisely.

Investigation on soil-transmitted nematode infections in national surveil-lance sites in Jiangsu Province from 2006 to 2015 / 中国血吸虫病防治杂志

Objective To understand the status of soil?transmitted nematode infections in rural residents so as to provide the evidence for formulating the guidance for prevention and control of the diseases. Methods The national surveillance sites of soil?transmitted nematode infections were established in Shuyang County,Suqian City,Jiangsu Province from 2006 to 2015. At least 1 000 fecal samples of residents aged 3 years or above were collected in every autumn,and the intestinal helminth eggs were detected with the Kato?Katz technique and the Enterubius vermicularis eggs were detected by the cellophane tape method for children aged 3-12 years. The soil samples were collected from vegetable fields,lavatories,courtyards and kitchens to exam?ine Ascaris lumbricoides eggs and larvae of hookworm. Results The infection rates of soil?transmitted nematodes in residents and E. vermicularis in children reduced from 1.81%(19/1 049)and 4.72%(5/106)in 2006 to 0.25%(3/1 180)and 0(0/263) in 2015,respectively,in the surveillance sites. The infection intensity was mild in all the infected cases. The soil samples were negative for detecting A. lumbricoides eggs and hookworm larvae. Conclusion The infection rates of soil?transmitted nema?todes in the residents and E. vermicularis in the children show a decreasing trend and keep at a low level of prevalence in Shuy?ang County.

Injectable biphasic calcium phosphate cements as a potential bone substitute.

Apatitic calcium phosphate cements (CPCs) have been widely used as bone grafts due to their excellent osteoconductive properties, but the degradation properties are insufficient to stimulate bone healing in large bone defects. A novel approach to overcome the lack of degradability of apatitic CPC involves the development of biphasic CPCs (BCPC) based on tricalcium phosphate (TCP) in both α- and ß-polymorphs. The aim of the current study was to prepare and analyze the physicochemical properties of BCPCs based on dual phase α/ß-TCP as obtained by heat treatment of pure α-TCP. The handling and mechanical characteristics of the samples as well as the degradation behavior under in vitro condition were investigated and compared with a standard monophasic α-TCP-based CPC. The results showed that different heat treatments of commercially available α-TCP allowed the formation of biphasic calcium phosphate powder with a variety of α/ß-TCP ratios. The use of biphasic powder particles as a reactant for CPCs resulted into increased setting and injectability times of the final BCPCs. During hardening of the cements, the amount of apatite formation decreased with increasing ß-TCP content in the biphasic precursor powders. The morphology of the monophasic CPC consisted of plate-like crystals, whereas needle-like crystals were observed for BCPCs. In vitro degradation tests demonstrated that dissolution rate and corresponding calcium release from the set cements increased considerably with increasing ß-TCP content, suggesting that apatitic CPCs can be rendered degradable by using biphasic α/ß-TCP as powder precursor phase.

Construction and Standardization Research on Hospital Medical Imaging Data Center Based on Clinical Data Repository / 中国医学影像学杂志

Hospital image information system is evolving from department-oriented to patient-oriented. This paper introduces the implementation of Beijing University People's Hospital image data center. The ideas, approaches and the technological standards for image data center's system integration are proposed. Additionally, the problems in practical application and the outlook for this system are discussed.

Effect of calcium carbonate on hardening, physicochemical properties, and in vitro degradation of injectable calcium phosphate cements.

The main disadvantage of apatitic calcium phosphate cements (CPCs) is their slow degradation rate, which limits complete bone regeneration. Carbonate (CO3²â») is the common constituent of bone and it can be used to improve the degradability of the apatitic calcium phosphate ceramics. This study aimed to examine the effect of calcite (CaCO3) incorporation into CPCs. To this end, the CaCO3 amount (0-4-8-12 wt %) and its particle size (12.0-µm-coarse or 2.5-µm-fine) were systematically investigated. In comparison to calcite-free CPC, the setting time of the bone substitute was delayed with increasing CaCO3 incorporation. Reduction of the CaCO3 particle size in the initial powder increased the injectability time of the paste. During hardening of the cements, the increase in calcium release was inversely proportional to the extent of CO3²â» incorporation into apatites. The morphology of the carbonate-free product consisted of large needle-like crystals, whereas small plate-like crystals were observed for carbonated apatites. Compressive strength decreased with increasing CaCO3 content. In vitro accelerated degradation tests demonstrated that calcium release and dissolution rate from the set cements increased with increasing the incorporation of CO3²â», whereas differences in CaCO3 particle size did not affect the in vitro degradation rate under accelerated conditions.

In vitro and in vivo evaluation on the bioactivity of ZnO containing nano-hydroxyapatite/chitosan cement.

A ZnO containing nano-hydroxyapatite/chitosan (n-HA/CS) cement was developed and its bone formation ability was investigated in vitro and in vivo. The physico-chemical properties of the cement were determined in terms of pH variation during and after setting, injectability and wettability. The results indicated that, the pH varied from 7.04 to 7.12 throughout the soaking of the cement in distilled water. The injectability was excellent during the first 4 min, but the cement became less injectable or even not injectable at all after 7 min setting. The static contact angle of the cement against water was 53.5 +/- 2.7 degrees . The results of immersion tests in simulated body fluid (SBF) indicated that the cement exhibited excellent bone-like apatite forming ability. In vivo studies, involving the installation of the cement of tibial-bone defects in rabbit tibia revealed an inflammatory response around the cement at 3 days of implantation. After 4 weeks, the inflammation began to disappear and the cement had bound to the surrounding host bone. Radiological examination also confirmed that the ZnO containing n-HA/CS cement significantly induced new bone formation. These results suggest that the ZnO containing n-HA/CS cement may be beneficial to enhance bone regeneration in osseous defect sites.

Preparation and biological properties of a novel composite scaffold of nano-hydroxyapatite/chitosan/carboxymethyl cellulose for bone tissue engineering.

In this study, we report the physico-chemical and biological properties of a novel biodegradable composite scaffold made of nano-hydroxyapatite and natural derived polymers of chitosan and carboxymethyl cellulose, namely, n-HA/CS/CMC, which was prepared by freeze-drying method. The physico-chemical properties of n-HA/CS/CMC scaffold were tested by infrared absorption spectra (IR), transmission electron microscope(TEM), scanning electron microscope(SEM), universal material testing machine and phosphate buffer solution (PBS) soaking experiment. Besides, the biological properties were evaluated by MG63 cells and Mesenchymal stem cells (MSCs) culture experiment in vitro and a short period implantation study in vivo. The results show that the composite scaffold is mainly formed through the ionic crossing-linking of the two polyions between CS and CMC, and n-HA is incorporated into the polyelectrolyte matrix of CS-CMC without agglomeration, which endows the scaffold with good physico-chemical properties such as highly interconnected porous structure, high compressive strength and good structural stability and degradation. More important, the results of cells attached, proliferated on the scaffold indicate that the scaffold is non-toxic and has good cell biocompatibility, and the results of implantation experiment in vivo further confirm that the scaffold has good tissue biocompatibility. All the above results suggest that the novel degradable n-HA/CS/CMC composite scaffold has a great potential to be used as bone tissue engineering material.

A novel composite membrane of chitosan-carboxymethyl cellulose polyelectrolyte complex membrane filled with nano-hydroxyapatite I. Preparation and properties.

A novel tri-component composite membranes of chitosan/carboxymethyl cellulose (CS/CMC) polyelectrolyte complex membranes filled with different weight ratios of nano-hydroxyapatite (n-HA)(0, 20, 40 and 60 wt%), namely, n-HA/CS/CMC composite membrane, were prepared by self-assembly of static electricity. The structure and the properties of the composite membranes were investigated by Fourier transformed infrared spectroscopy(IR), X-ray diffraction(XRD), Scanning electron microscopy(SEM), mechanical performance measurement, swelling behavior test, and soaking behavior study in phosphate buffered saline (PBS) and simulate body fluid (SBF). The results showed that the n-HA/CS/CMC composite membrane was formed though superficial static electricity interaction among n-HA, CS and CMC. For the n-HA/CS/CMC composite membrane, the microstructure compatibility, mechanical property, swelling behavior, the degradation and bioactivity in vitro of the composite membrane were improved by the addition of n-HA, compared with CS/CMC polyelectrolyte complex membrane. Moreover, the n-HA/CS/CMC composite membrane with 40 wt% n-HA had the most highest mechanical property, which suggested that the novel n-HA/CS/CMC composite membrane with 40 wt% n-HA was more suitable to be used as guided bone tissue regeneration membrane than CS/CMC polyelectrolyte complex membrane.

Preparation and characterization of nano-hydroxyapatite/polyurethane composite bio-film / 生物医学工程学杂志

Through Hydroxyl (-OH) reacting with isocyanate group (-NCO), 13 Wt% nano-hydroxyapatite (n-HA)/polyurethane (PU) composite guided bone regeneration membrane was synthesized by use of solvent evaporation method. Its surface character was analyzed by XRD, IR, TG, contact angle, water absorption, elongation and combustion test and SEM. The results indicate that nano-HA/PU has good homogeneity,the interface between the inorganic mineral and organic polymer is optimized to create proper combination; that n-HA crystals are similar to the apatite crystals in natural bone, HA/PU composite membrane has good hydrophilicity mechanical behavior; and that many pores are observed on the membrane which help cells' metabolism. So the HA/PU composite membrane, thus prepared, has the potential for use in guided bone regeneration and tissue engineering.

Preparation and properties of a novel bone repair composite: nano-hydroxyapatite/chitosan/carboxymethyl cellulose.

Nano-hydroxyapatite/chitosan/carboxymethyl cellulose (n-HA/CS/CMC) composites with weight ratios of 70/10/20, 70/15/15 and 70/20/10 were prepared through a co-solution method. The properties of the composites were characterized by means of burn-out test, IR, XRD, TEM and universal material testing machine. The degradation and bioactivity were also investigated by in vitro test in a simulated body fluid (SBF) for 8 weeks. The results showed that n-HA particles were dispersed uniformly in organic phase, and strong chemical interactions formed among the three phases. Moreover, the composites were similar to natural bone in morphology and size. In addition, the compressive strength was improved compared with n-HA/CS composite. The biodegradation rate was controllable by altering weight ratio of the CS/CMC. Meanwhile, the composites could induce apatite particles to deposit in SBF. All the above results indicate that the novel composites of n-HA/CS/CMC have a promising prospect used for bone repair materials in view of the good mechanical property, adjustable biodegradation rate and bioactivity in SBF. Additionally, the study would provide a good guide to exploit clinical application of natural cellulose.

Preparation and biological safety evaluation of porous n-HA/PA66 composite / 生物医学工程学杂志

Porous nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composite was developed by injection molding method. Uniformly distributed and interconnected pores with an average size of about 500 microm in matrix were obtained. The evaluation of biological safety of the porous composite including cell cytoxicity test, sensitivity test, pyrogen test, haemolysis test was carried out according to GB/T16886 and GB/T16175. The results showed that the porous n-HA/PA66 composite was of no cytotoxicity, no allergen and pyrogen reactions as well as no hemolytic effect.

Preliminary studies on repairing osteochondral defects in the rabbit knee joint by using porous PA66/n-HA combination mesenchymal stem cells / 生物医学工程学杂志

We have investigated the effects of repairing knee osteochondral defects in rabbit by using porous polyamide 66/nano-Hydroxyapatite (PA66/n-HA) combination bone marrow mesenchymal stem cells (MSCs). Eighteen 6-month-old New Zealand rabbits were used to produce the models of 4 mm x 4 mm osteochondral defect in the middle trochlea groove of femur. These models were randomly divided into 3 groups: PA66/n-HA + MSCs Group (Group A), PA66/n-HA group (Group B) and Operation control-group (Group C) in which operation for osteochondral defects was performed but neither material nor cells were implanted. The materials in Group A were seeded with MSCs (5 x 10(5)) in vitro before being implanted in to defects. The materials in groups A and B were 0.5 - 0.8 mm lower than normal cartilage. The animals were killed 1 and 4 months after operation. We assessed the effects by means of macroscopic observation, HE staining, toluidine blue staining, immunohistochemistry assay for type I and type II collagen. Group A displayed a little effect at the 1 month, but at the 4th month, Group A showed better results,compared to Groups B and C. At this time point, the repair tissue of Group A was regular; it presented more metachromatic substance visualized by toluidine blue staining, and it expressed type II collagen(+ +) and type I collagen(+). These results demonstrate that the repair tissue in Group A is nearly hyaline cartilage. So we presume that porous PA66/n-HA provides biomechanical support, and at the same time, MSCs enhance the repair effects.

Preparation and in vivo investigation of artificial cornea made of nano-hydroxyapatite/poly (vinyl alcohol) hydrogel composite.

An artificial cornea consisted of a porous nano-hydroxyapatite/poly (vinyl alcohol) hydrogel (n-HA/PVA-H) skirt and a transparent center poly (vinyl alcohol) hydrogel (PVA-H) were prepared. The n-HA/PVA-H skirt was homogeneously porous and these pores were interconnected. Inter-penetrating network was observed along the interface between the core and the skirt. Artificial corneas were implanted in eyes of rabbit. The corneal tissues were evaluated histological. The results displayed that a good biocompatibility and interlocking had happened between artificial cornea and host tissues. This novel cornea prepared here is potential to be used clinically.

Preliminary investigation of bioactivity of nano biocomposite.

Bioactive biomaterials can form a bone-like apatite layer on their surfaces in the body, which is critical to establishing bone bonding between bioactive materials and living tissue. At present study, the bone-like apatite formation in vitro and vivo on the surface of the nano apatite/polyamide composite was studied, and the bioactive composites implanted into the femora of rabbits were also investigated. The results revealed that the bone-like apatite containing carbonate can form on the surface of the biocomposite both in SBF and dorsal muscle of rabbits, and the composite would form directly combination with the natural bone without fibrous capsule tissue between implant and host bone tissue. All of these indicated that the nano biocomposites have excellent bioactivity and can be used for bone replacement.

In vitro evaluation of different heat-treated radio frequency magnetron sputtered calcium phosphate coatings.

OBJECTIVES: Surface chemical compositions, such as calcium/phosphorus ratio and phase content, have a strong influence on the bioactivity and biocompatibility of calcium phosphate (CaP) coatings as applied on orthopedic and dental implants. MATERIAL AND METHODS: Hydroxylapatite (HA) and dicalcium pyrophosphate (DCPP) coatings were prepared on titanium substrates by RF magnetron sputter deposition. The surfaces were left as-prepared (amorphous HA coating; A-HA, amorphous DCPP coating; A-DCPP) or heat treated with: infrared (IR) at 550 degrees C (I-HA) or at 650 degrees C (I-DCPP), and a water steam at 140 degrees C (S-HA and S-DCPP). The surface changes of these coatings were determined after incubation in simulated body fluid (SBF). Also, the growth of rat bone marrow cells (RBM) was studied with scanning electron microscopy (SEM). RESULTS: Both IR and water steam heat treatment changed the sputter-deposited coatings from the amorphous into the crystalline phase. As-prepared amorphous coatings dissolved partially in SBF within 4 weeks of incubation, while heat-treated coatings supported the deposition of a precipitate, i.e., carbonated apatite on both I-HA and S-HA specimens, and tricalciumphosphate on the I-DCPP and S-DCPP specimens. The Ca/P ratio of the A-HA, I-HA, S-HA, A-DCPP, I-DCPP and S-DCPP coatings changed, respectively, from 1.98 to 1.12, 2.01 to 1.76, 1.91 to 1.68, 0.76 to 1.23, 0.76 to 1.26 and 1.62 to 1.55 after 4 weeks of incubation in SBF. Finally, the RBM cells grew well on all heat-treated coatings, but showed different mineralization morphology during cell culturing. CONCLUSION: The different heat-treatment procedures for the sputtered HA and DCPP coatings influenced the surface characteristics of these coatings, whereby a combination of crystallinity and specific phase composition (Ca/P ratio) strongly affected their in vitro bioactivity.

The influence of discharge power and heat treatment on calcium phosphate coatings prepared by RF magnetron sputtering deposition.

Ca-P coatings with different Ca/P ratio and composition were successfully prepared by RF magnetron sputtering deposition. The Ca/P ratio, phase composition, structure and morphological properties were characterized by XRD, FTIR, EDS and SEM analyses. All the as-sputtered coatings were amorphous and after IR-irradiation the coatings altered into a crystalline phase. The obtained coatings had a Ca/P ratio that varied from 0.55 to 2.10 and different phase compositions or mixtures of apatite, beta-pyrophosphate and beta-tricalciumphosphate structures were formed. Evidently, the phase compositions of the sputtered coatings are determined not only by the discharge power ratio of the hydroxylapatite and calcium pyrophosphate targets but also by the annealing temperature.

Growth behavior of rat bone marrow cells on RF magnetron sputtered hydroxyapatite and dicalcium pyrophosphate coatings.

The aim of this study was to evaluate the osteogenic properties of magnetron sputtered dicalcium pyrophaosphate (DCPP) and hydroxylapatite (HA) coatings. Therefore, DCPP and HA coatings were deposited on grit-blasted titanium discs. The substrates were used as-prepared or received an additional heat treatment which changed the amorphous coating structure to a crystalline structure. Subsequently, rat bone marrow stromal cells were cultured for 1-24 days on the various substrates. DNA and alkaline phosphatase activity was determined after 1, 3, 5, 8, and 12 days of incubation. Osteocalcin expression was evaluated after 8, 12, 16, and 24 days of incubation. Scanning electron microscopical analysis of cell morphology and coating characteristics was done after 8 and 16 days of incubation. All assays were done in duplicate and in each assay all specimens were present in fourfold. Results demonstrated that the cells did not proliferate and differentiate on all amorphous coatings. SEM revealed that the amorphous coatings showed significant dissolution. On the crystalline DCPP and HA coatings an increase in DNA and alkaline phosphatase activity was seen starting at day 8 of incubation. Osteocalcin expression on the crystalline coatings started to increase at day 16 of incubation. SEM showed that the growth and differentiation of the cells was associated with extensive collagen fiber formation and surface mineralization in the form of globular accretions. Further, statistical testing revealed that proliferation and differentiation of the rat bone marrow stromal cells started significantly earlier on the crystalline HA coatings than that on the crystalline DCPP coatings. These results demonstrate that the rat bone marrow stromal cells proliferated and differentiated only on crystalline magnetron sputtered DCPP as well as HA coatings, which warrants the further in vivo analysis of the bone healing supporting properties of these coatings.

Subcutaneous evaluation of RF magnetron-sputtered calcium pyrophosphate and hydroxylapatite-coated Ti implants.

The in vivo behavior of infrared-heated, RF magnetron-sputtered hydroxylapatite (HA) and calcium pyrophosphate (DCPP) coated titanium discs was investigated. The discs were implanted subcutaneously in the back of six goats for 2, 4, 8 and 12 weeks. At the end of the study, coated discs were removed and examined on their physicochemical properties by X-ray diffraction (XRD) and scanning electron microscopy (SEM), including energy dispersive spectroscopy (EDS). Also, implants were prepared for light microscopical evaluation of the tissue response. The results showed that heat-treated HA coatings showed a stable behavior, i.e. no changes in the XRD pattern occurred during implantation. Also, no dissolution of the coating was observed by SEM. EDS revealed that the Ca/P ratio of the HA coatings remained stable during implantation. In contrast, heat-treated DCPP coatings showed a compositional change into apatite and tricalcium phosphate (TCP) during implantation. This was confirmed by the SEM and EDS analysis. The Ca/P ratio of the DCPP coatings changed from 0.8 to 1.52 during implantation. Finally, histology showed that both heat-treated HA and DCPP coatings showed no adverse tissue response, as characterized by the presence of thin, dense fibrous tissue capsule. Consequently, it can be concluded that 2 mum thick heat-treated, RF magnetron-sputtered HA and DCPP coatings are of sufficient thickness to withstand dissolution during 12 weeks of implantation in a subcutaneous location in goats. In addition, both coatings showed a biocompatible tissue behavior. Further, heat-treated DCPP coatings revealed a gradual compositional change into apatite and TCP.

Preparation and characterization of RF magnetron sputtered calcium pyrophosphate coatings.

CaP ceramic has been widely used as coating on metals in orthopedics and oral dentistry. Variations in CaP composition can lead to different dissolution/precipitation behavior and may also affect the bone response. In the present study calcium pyrophosphate and hydroxylapatite coatings were successfully prepared by RF magnetron sputtering deposition. The phase composition, morphological properties, and the dissolution in SBF were characterized by using XRD, FTIR, EDS, SEM, and spectrophotometry. The results showed that all the sputtered coatings were amorphous and changed into a crystal structure after IR-radiation. The temperature for the crystallization of the amorphous coatings is lower for the hydroxylapatite coating (550 degrees C), compared to the calcium pyrophosphate coating (650 degrees C). All sputtered amorphous coatings were instable in SBF and dissolved partially within 4 wks of incubation. The heat-treated coatings appeared to be stable after incubation. These results showed that magnetron sputtering of calcium pyrophosphate coating is a promising method for forming a biocompatible ceramic coating.

Preparation and in vitro investigation of chitosan/nano-hydroxyapatite composite used as bone substitute materials.

Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca(OH)(2), H(3)PO(4) and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, burn-out test and universal matertial test machine. Additionally, in vitro tests were also conducted to investigate the biodegradability and bioactivity of the composite. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there is no phase-separation between the two phases. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured about 120 MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70. The specimens made of 30/70 chitosan/n-HA composite exhibit high biodegradability and bioactivity when being immersed in SBF solutions. The composite is appropriate to being used as scaffold materials for bone tissue engineering. (c) Springer Science + Business Media, Inc.