2,503 research outputs found

    Delimitation of Neonectria and Cylindrocarpon (Nectriaceae, Hypocreales, Ascomycota) and related genera with Cylindrocarpon-like anamorphs

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    Neonectria is a cosmopolitan genus and it is, in part, defined by its link to the anamorph genus Cylindrocarpon. Neonectria has been divided into informal groups on the basis of combined morphology of anamorph and teleomorph. Previously, Cylindrocarpon was divided into four groups defined by presence or absence of microconidia and chlamydospores. Molecular phylogenetic analyses have indicated that Neonectria sensu stricto and Cylindrocarpon sensu stricto are phylogenetically congeneric. In addition, morphological and molecular data accumulated over several years have indicated that Neonectria sensu lato and Cylindrocarpon sensu lato do not form a monophyletic group and that the respective informal groups may represent distinct genera. In the present work, a multilocus analysis (act, ITS, LSU, rpb1, tef1, tub) was applied to representatives of the informal groups to determine their level of phylogenetic support as a first step towards taxonomic revision of Neonectria sensu lato. Results show five distinct highly supported clades that correspond to some extent with the informal Neonectria and Cylindrocarpon groups that are here recognised as genera: (1) N. coccinea-group and Cylindrocarpon groups 1 & 4 (Neonectria/Cylindrocarpon sensu stricto); (2) N. rugulosa-group (Rugonectria gen. nov.); (3) N. mammoidea/N. veuillotiana-groups and Cylindrocarpon group 2 (Thelonectria gen. nov.); (4) N. radicicola-group and Cylindrocarpon group 3 (Ilyonectria gen. nov.); and (5) anamorph genus Campylocarpon. Characteristics of the anamorphs and teleomorphs correlate with the five genera, three of which are newly described. New combinations are made for species where their classification is confirmed by phylogenetic data

    Whole-genome association analysis of treatment response in obsessive-compulsive disorder.

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    Up to 30% of patients with obsessive-compulsive disorder (OCD) exhibit an inadequate response to serotonin reuptake inhibitors (SRIs). To date, genetic predictors of OCD treatment response have not been systematically investigated using genome-wide association study (GWAS). To identify specific genetic variations potentially influencing SRI response, we conducted a GWAS study in 804 OCD patients with information on SRI response. SRI response was classified as 'response' (n=514) or 'non-response' (n=290), based on self-report. We used the more powerful Quasi-Likelihood Score Test (the MQLS test) to conduct a genome-wide association test correcting for relatedness, and then used an adjusted logistic model to evaluate the effect size of the variants in probands. The top single-nucleotide polymorphism (SNP) was rs17162912 (P=1.76 × 10(-8)), which is near the DISP1 gene on 1q41-q42, a microdeletion region implicated in neurological development. The other six SNPs showing suggestive evidence of association (P<10(-5)) were rs9303380, rs12437601, rs16988159, rs7676822, rs1911877 and rs723815. Among them, two SNPs in strong linkage disequilibrium, rs7676822 and rs1911877, located near the PCDH10 gene, gave P-values of 2.86 × 10(-6) and 8.41 × 10(-6), respectively. The other 35 variations with signals of potential significance (P<10(-4)) involve multiple genes expressed in the brain, including GRIN2B, PCDH10 and GPC6. Our enrichment analysis indicated suggestive roles of genes in the glutamatergic neurotransmission system (false discovery rate (FDR)=0.0097) and the serotonergic system (FDR=0.0213). Although the results presented may provide new insights into genetic mechanisms underlying treatment response in OCD, studies with larger sample sizes and detailed information on drug dosage and treatment duration are needed

    Finite temperature molecular dynamics study of unstable stacking fault free energies in silicon

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    We calculate the free energies of unstable stacking fault (USF) configurations on the glide and shuffle slip planes in silicon as a function of temperature, using the recently developed Environment Dependent Interatomic Potential (EDIP). We employ the molecular dynamics (MD) adiabatic switching method with appropriate periodic boundary conditions and restrictions to atomic motion that guarantee stability and include volume relaxation of the USF configurations perpendicular to the slip plane. Our MD results using the EDIP model agree fairly well with earlier first-principles estimates for the transition from shuffle to glide plane dominance as a function of temperature. We use these results to make contact to brittle-ductile transition models.Comment: 6 pages revtex, 4 figs, 16 refs, to appear in Phys. Rev.

    What Brown saw and you can too

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    A discussion is given of Robert Brown's original observations of particles ejected by pollen of the plant \textit{Clarkia pulchella} undergoing what is now called Brownian motion. We consider the nature of those particles, and how he misinterpreted the Airy disc of the smallest particles to be universal organic building blocks. Relevant qualitative and quantitative investigations with a modern microscope and with a "homemade" single lens microscope similar to Brown's, are presented.Comment: 14.1 pages, 11 figures, to be published in the American Journal of Physics. This differs from the previous version only in the web site referred to in reference 3. Today, this Brownian motion web site was launched, and http://physerver.hamilton.edu/Research/Brownian/index.html, is now correc

    Borrelia burgdorferi membranes are the primary targets of reactive oxygen species

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    Spirochetes living in an oxygen-rich environment or when challenged by host immune cells are exposed to reactive oxygen species (ROS). These species can harm/destroy cysteinyl residues, iron-sulphur clusters, DNA and polyunsaturated lipids, leading to inhibition of growth or cell death. Because Borrelia burgdorferi contains no intracellular iron, DNA is most likely not a major target for ROS via Fenton reaction. In support of this, growth of B. burgdorferi in the presence of 5 mM H2O2 had no effect on the DNA mutation rate (spontaneous coumermycin A1 resistance), and cells treated with 10 mM t-butyl hydroperoxide or 10 mM H2O2 show no increase in DNA damage. Unlike most bacteria, B. burgdorferi incorporates ROS-susceptible polyunsaturated fatty acids from the environment into their membranes. Analysis of lipoxidase-treated B. burgdorferi cells by Electron Microscopy showed significant irregularities indicative of membrane damage. Fatty acid analysis of cells treated with lipoxidase indicated that host-derived linoleic acid had been dramatically reduced (50-fold) in these cells, with a corresponding increase in the levels of malondialdehyde by-product (fourfold). These data suggest that B. burgdorferi membrane lipids are targets for attack by ROS encountered in the various stages of the infective cycle

    Molecular hierarchy of mammary differentiation yields refined markers of mammary stem cells

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    The partial purification of mouse mammary gland stem cells (MaSCs) using combinatorial cell surface markers (Lin-CD24+CD29hCD49fh) has improved our understanding of their role in normal development and breast tumorigenesis. Despite the significant improvement in MaSC enrichment, there is presently no methodology that adequately isolates pure MaSCs. Seeking new markers of MaSCs, we characterized the stem-like properties and expression signature of label-retaining cells from the mammary gland of mice expressing a controllable H2b-GFP transgene. In this system, the transgene expression can be repressed in a doxycycline-dependent fashion, allowing isolation of slowly dividing cells with retained nuclear GFP signal. Here, we show that H2b-GFPh cells reside within the predicted MaSC compartment and display greater mammary reconstitution unit frequency compared with H2b-GFPneg MaSCs. According to their transcriptome profile, H2b-GFPh MaSCs are enriched for pathways thought to play important roles in adult stem cells. We found Cd1d, a glycoprotein expressed on the surface of antigen-presenting cells, to be highly expressed by H2b-GFPh MaSCs, and isolation of Cd1d+ MaSCs further improved the mammary reconstitution unit enrichment frequency to nearly a single-cell level. Additionally, we functionally characterized a set of MaSC-enriched genes, discovering factors controlling MaSC survival. Collectively, our data provide tools for isolating a more precisely defined population of MaSCs and point to potentially critical factors for MaSC maintenance

    Routine testing for IgG antibodies against hepatitis A virus in Israel

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    BACKGROUND: Viral hepatitis is highly endemic in Israel, with the hepatitis A virus (HAV) responsible for most cases. Improved socioeconomic factors, as well as the universal vaccination of infants (introduced in 1999) has resulted in a decline in infection rates in Israel. This study examines the benefits of routine testing for anti-HAV IgG in high-risk population. METHODS: A retrospective examination of the files of teenage and adult patients (aged 16–99 years; mean 33.9) in two primary care clinics found 1,017 patients who had been tested for anti-HAV IgG antibodies for either general healthcare screening or ongoing follow-up for chronic illness. Seropositive patients were then asked regarding recall of past hepatitis (i.e. jaundice, regardless of viral etiology); post-exposure prophylaxis with immune serum immunoglobulin (ISG); and active immunization with inactivated virus. Seronegative patients were subsequently sent for active immunization. RESULTS: Of the1,017 patient records studied (503 male, 514 female), a total of 692 were seropositive (354 males, 338 females; P = 0.113). Seropositivity rates increased with age (p < 0.005), and were highest among those born in Middle Eastern countries other than Israel (91.3%) and lowest among immigrants from South America (44.1%; P < 0.005). 456 of the seropositive patients were interviewed, of whom only 91 recalled past illness while 103 remembered receiving post-exposure prophylaxis (ISG) and 8 active vaccination. Those who were unaware of past infection were more likely to have been vaccinated with ISG than those who were aware (26.3% vs. 7.7%; p < 0.005). CONCLUSION: The relatively high prevalence rate of anti-HAV seropositivity in our study may me due to the fact that the study was conducted in a primary care clinic or that it took place in Jerusalem, a relatively poor and densely populated Israeli city. Most of the seropostive patients had no recollection of prior infection, which can be explained by the fact that most hepatitis A infections occur during childhood and are asymptomatic. Routine testing for anti-HAV IgG in societies endemic for HAV would help prevent seropositive patients from receiving either post-exposure or preventive immunization and target seronegative patients for preventive vaccination

    EGFR related mutational status and association to clinical outcome of third-line cetuximab-irinotecan in metastatic colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>As supplement to <it>KRAS </it>mutational analysis<it>, BRAF and PIK3CA </it>mutations as well as expression of PTEN may account for additional non-responders to anti-EGFR-MoAbs treatment. The aim of the present study was to investigate the utility as biomarkers of these mutations in a uniform cohort of patients with metastatic colorectal cancer treated with third-line cetuximab/irinotecan.</p> <p>Methods</p> <p>One-hundred-and-seven patients were prospectively included in the study. Mutational analyses of <it>KRAS, BRAF </it>and <it>PIK3CA </it>were performed on DNA from confirmed malignant tissue using commercially available kits. Loss of PTEN and EGFR was assessed by immunohistochemistry.</p> <p>Results</p> <p>DNA was available in 94 patients. The frequency of KRAS, <it>BRAF </it>and <it>PIK3CA </it>mutations were 44%, 3% and 14%, respectively. All were non-responders. EGF receptor status by IHC and loss of PTEN failed to show any clinical importance. <it>KRAS </it>and <it>BRAF </it>were mutually exclusive. Supplementing <it>KRAS </it>analysis with <it>BRAF </it>and <it>PIK3CA </it>indentified additional 11% of non-responders. Patient with any mutation had a high risk of early progression, whereas triple-negative status implied a response rate (RR) of 41% (p < 0.001), a disease control (DC) rate of 73% (p < 001), and a significantly higher PFS of 7.7(5.1-8.6 95%CI) versus 2.3 months (2.1-3.695%CI) (p < 0.000).</p> <p>Conclusion</p> <p>Triple-negative status implied a clear benefit from treatment, and we suggest that patient selection for third-line combination therapy with cetuximab/irinotecan could be based on triple mutational testing.</p
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