26 research outputs found

    Chemical warfare between leafcutter ant symbionts and a co-evolved pathogen

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    Acromyrmex leafcutter ants form a mutually beneficial symbiosis with the fungus Leucoagaricus gongylophorus and with Pseudonocardia bacteria. Both are vertically transmitted and actively maintained by the ants. The fungus garden is manured with freshly cut leaves and provides the sole food for the ant larvae, while Pseudonocardia cultures are reared on the ant-cuticle and make antifungal metabolites to help protect the cultivar against disease. If left unchecked, specialized parasitic Escovopsis fungi can overrun the fungus-garden and lead to colony collapse. We report that Escovopsis upregulates the production of two specialized metabolites when it infects the cultivar. These compounds inhibit Pseudonocardia and one, shearinine D, also reduces worker behavioral defences and is ultimately lethal when it accumulates in ant tissues. Our results are consistent with an active evolutionary arms race between Pseudonocardia and Escovopsis, which modifies both bacterial and behavioral defences such that colony collapse is unavoidable once Escovopsis infections escalate

    High sustained efficacy of a prophylactic quadrivalent human papillomavirus types 6/11/16/18 L1 virus-like particle vaccine through 5 years of follow-up

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    Human papillomavirus (HPV) causes cervical, vulvar, and vaginal cancers, precancerous dysplasia, and genital warts. We report data for the longest efficacy evaluation to date of a prophylactic HPV vaccine. In total, 552 women (16–23 years) were enrolled in a randomised, placebo-controlled study of a quadrivalent HPV 6/11/16/18 L1 virus-like-particle vaccine with vaccination at months 0, 2, and 6. At regular intervals through 3 years, subjects underwent gynaecologic examination, cervicovaginal sampling for HPV DNA, serum anti-HPV testing, and Pap testing, with follow-up biopsy as indicated. A subset of 241 subjects underwent two further years of follow-up. At 5 years post enrolment, the combined incidence of HPV 6/11/16/18-related persistent infection or disease was reduced in vaccine-recipients by 96% (two cases vaccine versus 46 placebo). There were no cases of HPV 6/11/16/18-related precancerous cervical dysplasia or genital warts in vaccine recipients, and six cases in placebo recipients (efficacy=100%; 95% CI:12–100%). Through 5 years, vaccine-induced anti-HPV geometric mean titres remained at or above those following natural infection. In conclusion, a prophylactic quadrivalent HPV vaccine was effective through 5 years for prevention of persistent infection and disease caused by HPV 6/11/16/18. This duration supports vaccination of adolescents and young adults, which is expected to greatly reduce the burden of cervical and genital cancers, precancerous dysplasia, and genital warts

    The JCMT Nearby Galaxies Legacy Survey – III. Comparisons of cold dust, polycyclic aromatic hydrocarbons, molecular gas and atomic gas in NGC 2403

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    ‘The definitive version is available at www3.interscience.wiley.com '. Copyright Royal Astronomical SocietyWe used Spitzer Space Telescope 3.6, 8.0, 70 and 160 μm data, James Clerk Maxwell Telescope HARP-B CO J= (3–2) data, National Radio Astronomy Observatory 12 m telescope CO J= (1–0) data and Very Large Array H i data to investigate the relations among polycyclic aromatic hydrocarbons (PAHs), cold (∼20 K) dust, molecular gas and atomic gas within NGC 2403, an SABcd galaxy at a distance of 3.13 Mpc. The dust surface density is mainly a function of the total (atomic and molecular) gas surface density and galactocentric radius. The gas-to-dust ratio monotonically increases with radius, varying from ∼100 in the nucleus to ∼400 at 5.5 kpc. The slope of the gas-to-dust ratio is close to that of the oxygen abundance, suggesting that metallicity strongly affects the gas-to-dust ratio within this galaxy. The exponential scale length of the radial profile for the CO J= (3–2) emission is statistically identical to the scale length for the stellar continuum-subtracted 8 μm (PAH 8 μm) emission. However, CO J= (3–2) and PAH 8 μm surface brightnesses appear uncorrelated when examining sub-kpc-sized regions.Peer reviewe

    The accuracy of colposcopic biopsy: Analyses from the placebo arm of the Gardasil clinical trials

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    We evaluated the overall agreement between colposcopically directed biopsies and the definitive excisional specimens within the context of three clinical trials. A total of 737 women aged 16-45 who had a cervical biopsy taken within 6 months before their definitive therapy were included. Per-protocol, colposcopists were to also obtain a representative cervical biopsy immediately before definitive therapy. Using adjudicated histological diagnoses, the initial biopsies and the same day biopsies were correlated with the surgically excised specimens. The overall agreement between the biopsies taken within 6 months of definitive therapy, and the definitive therapy diagnoses was 42% (weighted kappa = 0.34) (95% CI: 0.29-0.39). The overall underestimation of cervical intraepithelial neoplasia grade 2/3 or adenocarcinoma in situ (CIN2-3/AIS) and CIN3/AIS was 26 and 42%, respectively. When allowing for one degree of variance in the correlation, the overall agreement was 92% for CIN2-3/AIS. The overall agreement between the same day biopsy and definitive therapy specimen was 56% (weighted kappa = 0.41) (95% CI: 0.36-0.47), and the underestimation of CIN2-3/AIS was 57%. There were significant associations in the agreement between biopsies and excisional specimen diagnoses when patients were stratified by age, number of biopsies, lesion size, presence of human papillomavirus (HPV)16/18 and region. Of 178 diagnostic endocervical curettages performed, 14 (7.9%) found any HPV disease. Colposcopic accuracy improved when CIN2 and CIN3/AIS were grouped as a single predictive measure of high-grade disease. Colposcopy functioned well when allowed a one-degree difference between the biopsy and the surgical histologic interpretations, as done in clinical practice. Taking more than one biopsy improved colposcopic accuracy and could improve patient management. Copyright © 2010 UICC

    A post-hoc analysis of serotype-specific vaccine efficacy of 13-valent pneumococcal conjugate vaccine against clinical community acquired pneumonia from a randomized clinical trial in the Netherlands

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    Background: Serotype-specific vaccine efficacy (VE) against adult community acquired pneumonia (CAP) remains poorly defined, yet such data are important for assessing the utility of adult pneumococcal conjugate vaccine (PCV) programs. Methods: We evaluated the Community Acquired Pneumonia Immunization Trial in Adults to assess serotype-specific VE for CAP. This parallel-arm randomized clinical trial assessed 13-valent PCV (PCV13) VE among community dwelling persons aged ≥65 years in The Netherlands. In the original analysis, PCV13 VE against first episodes of vaccine-type (VT) chest radiology confirmed CAP was 45.6% (95% confidence interval [CI] 21.8–62.5%). Unlike the original analysis, we included any subject that met a clinical definition of CAP regardless of radiographic findings. VT-CAP was identified by culture (sterile or non-sterile) or serotype-specific urinary antigen detection (SSUAD) test. Only the five serotypes with at least 10 episodes in the control arm, based on the original analysis, were included for VE assessment. Results: Of 272 clinical CAP visits with VT serotypes identified, 253 (93%) were identified by SSUAD including 210 (77%) by SSUAD alone. VE was determined for serotypes 1, 3, 6A, 7F, and 19A, with total first episodes of, respectively, 27, 36, 25, 38, and 48. VE (95%CI) for the five evaluated serotypes against first clinical CAP episodes were: serotype 1, 20.0% (−83.1% to 65.8%); serotype 3, 61.5% (17.6–83.4%); serotype 6A, 33.3% (−58.6% to 73.2%); serotype 7F, 73.3% (40.5–89.4%); and serotype 19A, 45.2% (−2.2% to 71.5%). Discussion: Statistically significant VE was observed for serotypes 3 and 7F for clinical CAP among elderly community dwelling adults. The VE point estimates and CIs for serotypes 1, 6A, and 19A were lower but consistent with the overall VT-CAP VE of 45.6% previously reported. These findings may be relevant in models to accurately account for the potential impact of adult PCV13 immunization

    A public health evaluation of 13-valent pneumococcal conjugate vaccine impact on adult disease outcomes from a randomized clinical trial in the Netherlands

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    BACKGROUND: We conducted a post-hoc analysis of a double blind, randomized, placebo-controlled trial of 13-valent pneumococcal conjugate vaccine (PCV13) among adults aged 65 years or older to assess public health impact. METHODS: For all outcomes, we included all randomized subjects, using a modified intention-to-treat (mITT) approach to determine vaccine efficacy (VE), vaccine preventable disease incidence (VPDI) defined as control minus vaccinated group incidence, and numbers needed to vaccinate (NNV) (based on a five-year duration of protection). RESULTS: Results are reported for, in order, clinical, adjudicated (clinical plus radiologic infiltrate determined by committee), pneumococcal, and vaccine-type pneumococcal (VT-Sp) community-acquired pneumonia; invasive pneumococcal disease (IPD) and VT-IPD. VEs (95% CI) for all hospital episodes were 8.1% (-0.6%, 16.1%), 6.7% (-4.1%, 16.3%), 22.2% (2.0%, 38.3%), 37.5% (14.3%, 54.5%), 49.3% (23.2%, 66.5%), and 75.8% (47.6%, 88.8%). VPDIs per 100,000 person-years of observation (PYOs) were 72, 37, 25, 25, 20, and 15 with NNVs of 277, 535, 816, 798, 1016, and 1342. For clinical CAP, PCV13 was associated with a reduction of 909 (-115, 2013) hospital days per 100,000 PYOs translating to a reduction over 5 years of one hospital day for every 22 people vaccinated. When comparing at-risk persons (defined by self-report of diabetes, chronic lung disease, or other underlying conditions) to not at-risk persons, VEs were similar or lower, but because baseline incidences were higher the VPDIs were approximately 2-10 times higher and NNVs 50-90% lower. CONCLUSION: A public health analysis of pneumonia and IPD outcomes in a randomized controlled trial found substantial burden reduction following adult PCV13 immunization implemented in a setting with an ongoing infant PCV7-PCV10 program. VPDIs were higher among at-risk adults. FUNDING: The original study and the current analysis were funded by Pfizer
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