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Abstract Background Hepatitis B virus (HBV) exists in the breast milk of chronic hepatitis B (CHB) mothers. The authors use a meta-analytic technique to quantify the evidence of an association between breastfeeding and risk of CHB infection among the infants vaccinated against HBV. Methods Literature search is performed up to 2010 on the relationship between infantile CHB infection within one-year follow up after immunization with the third-dose hepatitis B vaccine and breastfeeding. Two reviewers independently extract the data and evaluate the methodological quality. A random-effects model is employed to systematically combine the results of all included studies. Results Based on data from 32 studies, 4.32% (244/5650) of infants born of CHB mothers develop CHB infection. The difference in risk of the infection between breastfed and formula-fed infants (RD) is -0.8%, (95% confidence interval [CI]: -1.6%, 0.1%). Analysis of the data from 16 of the studies finds that RD for mothers who are positive for the HBeAg and/or the HBV DNA, 0.7% (95%CI: -2.0%, 3.5%), is similar to that for those who are negative for these infectivity markers, -0.5% (95%CI: -1.7%, 0.6%). Conclusions Breast milk is infectious; yet, breastfeeding, even by mothers with high infectivity, is not associated with demonstrable risk of infantile CHB infection, provided that the infants have been vaccinated against HBV at birth.

The clinical use of FDA‐approved bone morphogenetic proteins (BMPs) are impeded by high costs, super‐high dosage requirement, short half‐life, and other undesirable side effects. Therefore, designing a biomaterial that can promote new bone formation without using exogenous BMPs is highly desirable in clinical applications. In the present work, a new kind of nanofibrous scaffold composed of gelatin and 45S5 bioglass (GF/45S5 BG) was prepared through thermally induced phase separation method together with the particle leach technique (TIPS&P). In addition to the significantly higher mechanical strength, the composite scaffolds (GF/45S5 BG) significantly increased osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro compared with the neat scaffold (GF) without adding other biological agents, for example, BMPs or hormones. Most importantly, our in vivo studies also indicated that GF/45S5 BG scaffolds could directly promote ectopic bone regeneration in SD rats without exogenous BMP2. In summary, both in vitro and in vivo results indicated that the novel 45S5 bioglass functionalized GF nanofibrous scaffold is a promising alternative for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Summary: A type II toxin‐antitoxin (TA) system, in which the toxin contains a Gcn5‐related N‐acetyltransferase (GNAT) domain, has been characterized recently. GNAT toxin acetylates aminoacyl‐tRNA and blocks protein translation. It is abolished by the cognate antitoxin that contains the ribbon‐helix‐helix (RHH) domain. Here, we present an experimental demonstration of the interaction of the GNAT‐RHH complex with TA promoter DNA. First, the GNAT‐RHH TA locus kacAT was found in Klebsiella pneumoniae HS11286, a strain resistant to multiple antibiotics. Overexpression of KacT halted cell growth and resulted in persister cell formation. The crystal structure also indicated that KacT is a typical acetyltransferase toxin. Co‐expression of KacA neutralized KacT toxicity. Expression of the bicistronic kacAT locus was up‐regulated during antibiotic stress. Finally, KacT and KacA formed a heterohexamer that interacted with promoter DNA, resulting in negative autoregulation of kacAT transcription. The N‐terminus region of KacA accounted for specific binding to the palindromic sequence on the operator DNA, whereas its C‐terminus region was essential for the inactivation of the GNAT toxin. These results provide an important insight into the regulation of the GNAT‐RHH family TA system. [ABSTRACT FROM AUTHOR]

Metal-mediated base pairs have been extensively utilized in many research fields, including genetic-code extension, novel therapeutics development, and nanodevice design. Compared to other cations, AgI is more flexible in pairing with natural base pairs. Herein, we present a DNA structure containing two C-AgI-C pairs and the first reported G-AgI-G pair in a short 8mer DNA strand. This structure not only provides detailed insight into these AgI-mediated base-pairing patterns in DNA, but also represents the first nonhelical DNA structure driven by heavy-metal ions, thus further contributing to the structural diversity of DNA. This unique complex structure is highly sequence-dependent, thus implying functional potentials as a new DNA aptamer that can bind and recognize silver ions. These results not only advance our understanding of the interactions between AgI and nucleobases, but also provide a unique structural component for the rational design of new DNA nanodevices. [ABSTRACT FROM AUTHOR]

Nanocomposites from nitrogen-doped graphene (NG) and magnetic nanoparticles (MNPs) are prepared via an edge-functionalized ball milling approach, followed by a coprecipitation method. Catalytic peroxidase-like activity of the resulting MNP/NG is investigated. The as-synthesized MNP/NG nanocomposites are used to catalyze the colorimetric reaction between hydrogen peroxide (H2O2) and 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Typical absorption peaks associated with the oxidation of ABTS are found to increase linearly with increasing H2O2 concentrations up to 10.0 × 10−3 m with a detection limit of 17.1 × 10−6 m. Rapid detection of H2O2 with the use of MNP/NG is confirmed further by a glucose biosensor. Concentrations of glucose could be monitored by detection of H2O2 since H2O2 is generated during oxidation of glucose by glucose oxidase (GOx). The absorption intensity increases significantly with increasing glucose amounts up to 18.0 × 10−3 m glucose, with a detection limit of 59.7 × 10−6 m, indicating a high performance for glucose detection. [ABSTRACT FROM AUTHOR]

Polymer-coated 45S5 Bioglass®(BG)/chitosan-polycaprolactone (BG/CS-PCL) bilayered composite scaffolds were prepared via foam replication and freeze-drying techniques for application in osteochondral tissue engineering. The CS-PCL coated and uncoated BG scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the coated scaffolds were significantly improved in comparison to uncoated scaffolds. The bioactivity and biodegradation behavior of scaffolds were studied in simulated body fluid (SBF) for up to 28 days. The interface between the BG scaffold and the polymer coating layer was observed by SEM and a suitable interpenetration of the polymer into the scaffold struts was found. The effects of coated and uncoated BG scaffolds on MG-63 osteoblast-like cells were evaluated by cell viability, adhesion and proliferation. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 4510-4518, 2014. [ABSTRACT FROM AUTHOR]

Calcium-deficient hydroxyapatite (cd-HA) crystals with a rod-like shape, 10-30 nm in diameter and 60-150 nm in length, were prepared via a hydrothermal method in the presence of poly(acrylic acid) (PAA) (in situ HA). Scaffolds composed of chitosan (CS), polycaprolactone (PCL) and in situ HA were prepared by freeze-drying, using a formic acid/acetone mixture as a shared solvent. The mass fraction of in situ HA in the scaffolds ranged from 0 to 40%. FT-IR and XRD studies indicated that hydrogen bonding interactions existed among CS, PCL and in situ HA, which suppressed the crystallization of PCL. The mechanical results demonstrated that the CS/PCL composites had the maximum flexural stress (308.14 ± 8.86 MPa), which was significantly higher than 2.92 ± 0.02 MPa for the CS/in situ HA control. The effects of scaffolds on MC3T3-E1 cells were studied by measuring the viability, proliferation, adhesion, alkaline phosphatase activity, as well as mineralization assay. The WST-1 assay showed that in situ HA-loaded scaffolds had higher cell viability than CS/PCL scaffolds. SEM images of the cell-seeded scaffolds revealed a significant promotion of cell adhesion in in situ HA-loaded scaffolds. Moreover, ALP and mineralization were found to be enhanced in in situ HA-loaded scaffolds. All these results indicate that in situ HA-loaded scaffolds support cellular functions of osteoblastic cells and may serve as promising bone scaffolds. [ABSTRACT FROM AUTHOR]

Metal-mediated base pairs have been extensively utilized in many research fields, including genetic-code extension, novel therapeutics development, and nanodevice design. Compared to other cations, Ag I is more flexible in pairing with natural base pairs. Herein, we present a DNA structure containing two C-Ag I -C pairs and the first reported G-Ag I -G pair in a short 8mer DNA strand. This structure not only provides detailed insight into these Ag I -mediated base-pairing patterns in DNA, but also represents the first nonhelical DNA structure driven by heavy-metal ions, thus further contributing to the structural diversity of DNA. This unique complex structure is highly sequence-dependent, thus implying functional potentials as a new DNA aptamer that can bind and recognize silver ions. These results not only advance our understanding of the interactions between Ag I and nucleobases, but also provide a unique structural component for the rational design of new DNA nanodevices., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Owing to their great potentials in genetic code extension and the development of nucleic acid-based functional nanodevices, DNA duplexes containing HgII-mediated base pairs have been extensively studied during the past 60 years. However, structural basis underlying these base pairs remains poorly understood. Herein, we present five high-resolution crystal structures including one first-time reported C-HgII-T containing duplex, three T-HgII-T containing duplexes and one native duplex containing T-T pair without HgII. Our structures suggest that both C-T and T-T pairs are flexible in interacting with the HgII ion with various binding modes including N3-HgII-N3, N4-HgII-N3, O2-HgII-N3 and N3-HgII-O4. Our studies also reveal that the overall conformations of the C-HgII-T and T-HgII-T pairs are affected by their neighboring residues via the interactions with the solvent molecules or other metal ions, such as SrII. These results provide detailed insights into the interactions between HgII and nucleobases and the structural basis for the rational design of C-HgII-T or T-HgII-T containing DNA nanodevices in the future., (© The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.)

The development of drug delivery coating systems for local and long-term drug release is gaining increasing interest especially to functionalize bioinert implants with osseointegration and antibacterial properties. In this study, a biodegradable drug delivery coating platform consisting of drug-loaded PHBV microspheres embedded in an alginate-PVA matrix was fabricated by a one-step electrophoretic deposition (EPD) process. Layer by layer (LbL) deposition was exploited to generate chitosan-alginate multilayers on the EPD-produced coating to enlarge the diffusional barrier around the microspheres for controlled drug release. Daidzein, selected as a model drug due to its anti-osteoporosis properties, was pre-encapsulated in PHBV microspheres. The parameters for microsphere fabrication were optimized by an orthogonal design approach. The loading efficiency of daidzein in both the microspheres and in the deposited coatings was adjusted by varying the processing parameters during microsphere fabrication and the EPD process. The degradation of the deposited multilayers was investigated in PBS for up to 14 days. The degradation rate, surface roughness and wettability, as well as adhesion strength of the coatings during degradation were evaluated by applying a range of techniques. A controlled and sustained daidzein release was detected from both free microspheres and microsphere-containing coatings. Finally cytotoxicity and stimulatory effects of daidzein or daidzein-loaded coatings, on both MC3T3-E1 and RAW264.7 cell lines, were studied to validate the potential of the developed coatings for orthopedic applications.