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Theaim of this study is to fabricate a contrast agent for magneticresonance imaging (MRI) by using hybrid particles composed of a coreof iron oxide magnetite (Fe3O4) nanoparticlesand a shell of hydrophilic polymer brush synthesized by surface-initiated(SI) living radical polymerization. To achieve this, Fe3O4nanoparticles were surface-modified with initiatinggroups for atom transfer radical polymerization (ATRP) via a ligand-exchangereaction in the presence of a triethoxysilane derivative having anATRP initiation site. The ATRP-initiator-functionalized Fe3O4nanoparticles were used for performing the SI-ATRPof methyl methacrylate to demonstrate the ability of the synthesizednanoparticles to produce well-defined polymer brushes on their surfaces.The polymerization proceeded in a living fashion so as to producegraft polymers with targeted molecular weights and narrow molecularweight distribution. The average graft density was estimated to beas high as 0.7 chains/nm2, which indicates the formationof so-called concentrated polymer brushes on the Fe3O4nanoparticles. Dynamic light scattering and transmissionelectron microscope observations of the hybrid nanoparticles revealedtheir uniformity and dispersibility in solvents to be excellent. Asimilar polymerization process was conducted using a hydrophilic monomer,poly(ethylene glycol) methyl ether methacrylate (PEGMA), to prepareFe3O4nanoparticles grafted with poly(PEGMA)brushes. The resultant hybrid nanoparticles showed excellent dispersibilityin aqueous media including physiological conditions without causingany aggregations. The blood clearance and biodistribution of the hybridparticles were investigated by intravenously injecting particles labeledwith a radio isotope, 125I, into mice. It was found thatsome hybrid particles exhibited an excellently prolonged circulationlifetime in the blood with a half-life of about 24 h. When such hybridparticles were injected intravenously into a tumor-bearing mouse,they preferentially accumulated in the tumor tissues owing to theso-called enhanced permeability and retention effect. The tumor-targeteddelivery was visualized by a T2-enhacedMRI measurement. [ABSTRACT FROM AUTHOR]

Corelike structures, which were interpreted as straight, large cylinders containing ribosome-like particles surrounded by an amorphous substance of low electron density, were found in a stable L-form of Streptococcus pyogenes grown in the absence of antibiotics. [ABSTRACT FROM AUTHOR]

Ultrastructure of an unstable L-form strain P42L induced from was demonstrated. The L-form grown in L-form media was composed of large cells and small vesicular structures. The L-form cell was spherical in shape measuring 2μm to 10μm in diameter and bounded by a cell wall which was thinner and somewhat damaged. In some cell, whorl-like membrane structures composing of a unit membrane arranged in several or more layers and small vesicular ones were found in the cytoplasm. The extracellular vesicular structures bounded by a triple-layered membrane, which measured 35 nm in diameter and seemed to be originated from outer membrane of the L-form cells, were also observed around the large cells. It is suggested that the unstable L-form is able to synthesize its cell wall components, but has not potentiality to build up completely into a cell wall structure. [ABSTRACT FROM PUBLISHER]

Daclatasvir (DCV) + asunaprevir (ASV) combination therapy has become available for patients with hepatitis C virus (HCV) serogroup 1 infection. We studied the efficacy of this therapy by focusing on the factors associated with sustained virological responses (SVR) including resistance-associated variants (RAVs) and mixed infection of different HCV genotypes. We enrolled 951 HCV serogroup 1-positive patients who received this combination therapy at our hospital or affiliated hospitals. The presence of RAVs in non-structural (NS) regions 3 and 5A was analyzed by direct sequencing. HCV genotypes were determined by PCR with genotype-specific primers targeting HCV core and NS5B regions. SVR was achieved in 91.1% of patients. Female sex, age > 70 years, and RAVs were significantly associated with non-SVR (p<0.01 for all). Propensity score-matching results among the patients without RAVs regarding sex, age, and fibrosis revealed that mixed HCV infection determined by HCV NS5B genotyping showed significantly lower SVR rates than 1B-mono infection (p=0.02). Female sex and RAVs were significant factors associated with treatment failure of this combination therapy for patients with HCV serogroup 1 infection. Mixed HCV infection other than 1B-mono infection would be useful for predicting treatment failure., Competing Interests: No potential conflict of interest relevant to this article was reported.