403 research outputs found

    Morphological and Pathological Evolution of the Brain Microcirculation in Aging and Alzheimer’s Disease

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    Key pathological hallmarks of Alzheimer’s disease (AD), including amyloid plaques, cerebral amyloid angiopathy (CAA) and neurofibrillary tangles do not completely account for cognitive impairment, therefore other factors such as cardiovascular and cerebrovascular pathologies, may contribute to AD. In order to elucidate the microvascular changes that contribute to aging and disease, direct neuropathological staining and immunohistochemistry, were used to quantify the structural integrity of the microvasculature and its innervation in three oldest-old cohorts: 1) nonagenarians with AD and a high amyloid plaque load; 2) nonagenarians with no dementia and a high amyloid plaque load; 3) nonagenarians without dementia or amyloid plaques. In addition, a non-demented (ND) group (average age 71 years) with no amyloid plaques was included for comparison. While gray matter thickness and overall brain mass were reduced in AD compared to ND control groups, overall capillary density was not different. However, degenerated string capillaries were elevated in AD, potentially suggesting greater microvascular “dysfunction” compared to ND groups. Intriguingly, apolipoprotein ε4 carriers had significantly higher string vessel counts relative to non-ε4 carriers. Taken together, these data suggest a concomitant loss of functional capillaries and brain volume in AD subjects. We also demonstrated a trend of decreasing vesicular acetylcholine transporter staining, a marker of cortical cholinergic afferents that contribute to arteriolar vasoregulation, in AD compared to ND control groups, suggesting impaired control of vasodilation in AD subjects. In addition, tyrosine hydroxylase, a marker of noradrenergic vascular innervation, was reduced which may also contribute to a loss of control of vasoconstriction. The data highlight the importance of the brain microcirculation in the pathogenesis and evolution of AD

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Genes Differentially Expressed in Conidia and Hyphae of Aspergillus fumigatus upon Exposure to Human Neutrophils

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    Aspergillus fumigatus is the most common etiologic agent of invasive aspergillosis in immunocompromised patients. Several studies have addressed the mechanism involved in host defense but only few have investigated the pathogen's response to attack by the host cells. To our knowledge, this is the first study that investigates the genes differentially expressed in conidia vs hyphae of A. fumigatus in response to neutrophils from healthy donors as well as from those with chronic granulomatous disease (CGD) which are defective in the production of reactive oxygen species.Transcriptional profiles of conidia and hyphae exposed to neutrophils, either from normal donors or from CGD patients, were obtained by using the genome-wide microarray. Upon exposure to either normal or CGD neutrophils, 244 genes were up-regulated in conidia but not in hyphae. Several of these genes are involved in the degradation of fatty acids, peroxisome function and the glyoxylate cycle which suggests that conidia exposed to neutrophils reprogram their metabolism to adjust to the host environment. In addition, the mRNA levels of four genes encoding proteins putatively involved in iron/copper assimilation were found to be higher in conidia and hyphae exposed to normal neutrophils compared to those exposed to CGD neutrophils. Deletants in several of the differentially expressed genes showed phenotypes related to the proposed functions, i.e. deletants of genes involved in fatty acid catabolism showed defective growth on fatty acids and the deletants of iron/copper assimilation showed higher sensitivity to the oxidative agent menadione. None of these deletants, however, showed reduced resistance to neutrophil attack.This work reveals the complex response of the fungus to leukocytes, one of the major host factors involved in antifungal defense, and identifies fungal genes that may be involved in establishing or prolonging infections in humans

    The Fitness Cost of Antibiotic Resistance in Streptococcus pneumoniae: Insight from the Field

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    Laboratory studies have suggested that antibiotic resistance may result in decreased fitness in the bacteria that harbor it. Observational studies have supported this, but due to ethical and practical considerations, it is rare to have experimental control over antibiotic prescription rates.We analyze data from a 54-month longitudinal trial that monitored pneumococcal drug resistance during and after biannual mass distribution of azithromycin for the elimination of the blinding eye disease, trachoma. Prescription of azithromycin and antibiotics that can create cross-resistance to it is rare in this part of the world. As a result, we were able to follow trends in resistance with minimal influence from unmeasured antibiotic use. Using these data, we fit a probabilistic disease transmission model that included two resistant strains, corresponding to the two dominant modes of resistance to macrolide antibiotics. We estimated the relative fitness of these two strains to be 0.86 (95% CI 0.80 to 0.90), and 0.88 (95% CI 0.82 to 0.93), relative to antibiotic-sensitive strains. We then used these estimates to predict that, within 5 years of the last antibiotic treatment, there would be a 95% chance of elimination of macrolide resistance by intra-species competition alone.Although it is quite possible that the fitness cost of macrolide resistance is sufficient to ensure its eventual elimination in the absence of antibiotic selection, this process takes time, and prevention is likely the best policy in the fight against resistance

    Enamel-like apatite crown covering amorphous mineral in a crayfish mandible

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    Carbonated hydroxyapatite is the mineral found in vertebrate bones and teeth, whereas invertebrates utilize calcium carbonate in their mineralized organs. In particular, stable amorphous calcium carbonate is found in many crustaceans. Here we report on an unusual, crystalline enamel-like apatite layer found in the mandibles of the arthropod Cherax quadricarinatus (freshwater crayfish). Despite their very different thermodynamic stabilities, amorphous calcium carbonate, amorphous calcium phosphate, calcite and fluorapatite coexist in well-defined functional layers in close proximity within the mandible. The softer amorphous minerals are found primarily in the bulk of the mandible whereas apatite, the harder and less soluble mineral, forms a wear-resistant, enamel-like coating of the molar tooth. Our findings suggest a unique case of convergent evolution, where similar functional challenges of mastication led to independent developments of structurally and mechanically similar, apatite-based layers in the teeth of genetically remote phyla: vertebrates and crustaceans

    How a slow-ovipositing parasitoid can succed as a biological control agent of the invasive mealybug Phenacoccus peruvianus: implications for future classical and conservation biological control programs

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    [EN] Phenaccocus peruvianus Granara de Willink (Hemiptera: pseudococcidae) is an invasive mealybug that has become a pest of ornamental plants in Europe and has recently been detected in California, USA. In this work, we studied the tritrophic interaction among this mealybug, its main parasitoid Acerophagus n. sp. near coccois (Hymenoptera: Encyrtidae) and tending ants to disclose the success of this parasitoid controlling P. peruvianus. Acerophagus n. sp. near coccois accepted mealybugs for parasitism regardless of their size but did not hostfeed. We recorded three active defenses of P. peruvianus. Host handling time-consuming process that required more than 30 min. Tending ants, Lasius grandis (Hymenoptera: Encyrtidae), reduced the time spent by parasitoids in a patch and disrupted oviposition attempts. The low numbers of ants tending mealybugs colonies in Spain and France could explain why this parasitoid, with a long handling time, is an efficient biological control agent for P. peruvianus.Beltrà Ivars, A.; Soto Sánchez, AI.; Tena Barreda, A. (2015). How a slow-ovipositing parasitoid can succed as a biological control agent of the invasive mealybug Phenacoccus peruvianus: implications for future classical and conservation biological control programs. BioControl. 60(4):473-484. https://doi.org/10.1007/s10526-015-9663-6S473484604Arakelian G (2013) Bougainvillea mealybug (Phenacoccus peruvianus). Factsheet 2013. County of Los Angeles. Department of agricultural commissioner/weights and measures, USABartlett BR (1961) The influence of ants upon parasites, predators, and scale insects. Ann Entomol Soc Am 54:543–551Bartlett BR (1978) Pseudococcidae. In: Clausen CP (ed) Introduced parasites and predators of arthropod pests and weeds: a world review, 1st edn. Agricultural Research Service USDA, Washington, USA, pp 137–170Barzman MS, Daane KM (2001) Host-handling behaviors in parasitoids of black scale, Saissetia oleae (Homoptera: Coccidae): a case for ant-mediated evolution. J Anim Ecol 70:237–247Beltrà A, Soto A, Germain JF, Matile-Ferrero D, Mazzeo G, Pellizzari G, Russo A, Franco JC, Williams DJ (2010) The Bougainvillea mealybug Phenacoccus peruvianus, a rapid invader from South America to Europe. Entomol Hell 19:137–143Beltrà A, Garcia-Marí F, Soto A (2013a) Seasonal phenology, spatial distribution, and sampling plan for the invasive mealybug Phenacoccus peruvianus (Hemiptera: Pseudococcidae). J Econ Entomol 106:1486–1494Beltrà A, Tena A, Soto A (2013b) Fortuitous biological control of the invasive mealybug Phenacoccus peruvianus in Southern Europe. BioControl 58:309–317Beltrà A, Tena A, Soto A (2013c) Reproductive strategies and food sources used by Acerophagus n. sp. near coccois, a new successful parasitoid of the invasive mealybug Phenacoccus peruvianus. J Pest Sci 86:253–259Berlinger MJ, Golberg AM (1978) The effect of the fruit sepals on the citrus mealybug population and on its parasite. Entomol Exp Appl 24:238–243Blumstein DT, Daniel JC (2007) Quantifying behavior the JWatcher way. Sinauer Associates Inc., Sunderland, UKBoavida C, Ahounou M, Vos M, Neuenschwander P, van Alphen JJM (1995) Host stage selection and sex allocation by Gyranusoidea tebygi (Hymenoptera: Encyrtidae), a parasitoid of the mango mealybug, Rastrococcus invadens (Homoptera: Pseudococcidae). Biol Control 5:487–496Bokonon-Ganta AH, Neuenschwander P, van Alphen JJM, Vos M (1995) Host stage selection and sex allocation by Anagyrus mangicola (Hymenoptera: Encyrtidae), a parasitoid of the mango mealybug, Rastrococcus invadens (Homoptera: Pseudococcidae). Biol Control 5:479–486Bugila AAA, Franco JC, Borges da Silva E, Branco M (2014a) Defense response of native and alien mealybugs (Hemiptera: Pseudococcidae) against the solitary parasitoid Anagyrus sp. nr. pseudococci (Girault) (Hymenoptera: Encyrtidae). J Insect Behav 27:439–453Bugila AAA, Branco M, Borges da Silva E, Franco JC (2014b) Host selection behavior and specificity of the solitary parasitoid of mealybugs Anagyrus sp. nr. pseudococci (Girault) (Hymenoptera, Encyrtidae). Biocontrol Sci Techn 24:22–38Bynum EK (1937) Pseudococcobius terryi Fullaway, a Hawaiian parasite of Gray Sugarcane mealybug in the United States. J Econ Entomol 30:756–761Cadée N, van Alphen JJM (1997) Host selection and sex allocation in Leptomastidea abnormis, a parasitoid of the citrus mealybug Planococcus citri. Entomol Exp Appl 83:277–284Clausen CP (1924) The parasites of Pseudococcus maritimus (Ehrhorn) in California (Hymenoptera, Chalcidoidea). Part II. Biological studies and life histories. UC Pub Entomol 3:253–288Daane KM, Barzman MS, Caltagirone LE, Hagen KS (2000) Metaphycus anneckei and Metaphycus hageni: two discrete species parasitic on black scale, Saissetia oleae. BioControl 45:269–284Daane KM, Bentley WJ, Walton VM, Malakar-Kuenen R, Millar JC, Ingels CA, Weber EA, Gispert C (2006) New controls investigated for vine mealybug. Calif Agric 60:31–38Daane KM, Sime KR, Fallon J, Cooper ML (2007) Impacts of Argentine ants on mealybugs and their natural enemies in California’s coastal vineyards. Ecol Entomol 32:583–596De Farias AM, Hopper KR (1999) Oviposition behavior of Aphelinus asychis (Hymenoptera: Aphelinidae) and Aphidius matricariae (Hymenoptera: Aphidiidae) and defense behavior of their host Diuraphis noxia (Homoptera: Aphididae). Environ Entomol 28:858–862Dorn B, Mattiacci L, Bellotti AC, Dorn S (2001) Host specificity and comparative foraging behavior of Aenasius vexans and Acerophagus coccois, two endo-parasitoids of the cassava mealybug. Entomol Exp Appl 99:331–339Eisner T, Silberglied RE (1988) A chrysopid larva that cloaks itself in mealybug wax. Psyche 95:15–20Flanders SE (1963) Predation by parasitic Hymenoptera, the basis of ant-induced outbreaks of a host species. J Econ Entomol 56:116Foldi I (1983) Structure et fonctions des glandes tégumentaires de cochenilles Pseudococcines et de leurs secretions. Ann Soc Entomol Fr 19:155–156Foldi I (1997) Defense strategies in scale insects: phylogenetic inference and evolutionary scenarios (Hemiptera, Coccoidea). In: Grandcolas P (ed) The origin of biodiversity in insects: phylogenetic tests of evolutionary scenarios, 1st edn. Muséum National d’Histoire Naturelle, Paris, France, pp 203–230Godfray HCJ (1994) Parasitoids: behavioral and evolutionary ecology. Princeton University Press, Princeton, USAGonzález-Hernández H, Johnson MW, Reimer NJ (1999) Impact of Pheidole megacephala (F.) (Hymenoptera: Formicidae) on the biological control of Dysmicoccus brevipes (Cockerell) (Homoptera: Pseudococcidae). Biol Control 15:145–152Gross P (1993) Insect behavioral and morphological defenses against parasitoids. Annu Rev Entomol 38:251–273Gullan PJ (1997) Relationships with ants. In: Ben-Dov Y, Hodgson CJ (eds) Soft scale insects—their biology natural enemies and control, 1st edn. Elsevier, Amsterdam, The Netherlands, pp 351–373Gullan PJ, Kosztarab M (1997) Adaptations in scale insects. Annu Rev Entomol 42:23–50Hcidari M, Jahan M (2000) A study of ovipositional behavior of Anagyrus pseudococci a parasitoid of mealybugs. J Agric Sci Technol 2:49–53Honda JY, Luck RF (1995) Scale morphology effects on feeding behavior and biological control potential of Rhyzobius lophanthae (Coleoptera: Coccinellidae). Ann Entomol Soc Am 88:441–450Joyce AL, Hoddle MS, Bellows TS, Gonzalez D (2001) Oviposition behavior of Coccidoxenoides peregrinus, a parasitoid of Planococcus ficus. Entomol Exp Appl 98:49–57Karamaouna F (1999) Biology of the parasitoids Leptomastix epona (Walker) and Pseudaphycus flavidulus (Brèthes) and behavioural interactions with the host mealybug Pseudococcus viburni (Signoret). Ph.D. Thesis, University of London, UK, p 333Karamaouna F, Copland MJ (2000) Oviposition behavior, influence of experience on host size selection, and niche overlap of the solitary Leptomastix epona and the gregarious Pseudaphycus flavidulus, two endoparasitoids of the mealybug Pseudococcus viburni. Entomol Exp Appl 97:301–308Klotz JH, Hansen L, Pospischil R, Rust M (2008) Urban ants of North America and Europe. Cornell University Press, Ithaca, USAMailleux AC, Deneubourg JL, Detrain C (2003) Regulation of ants foraging to resource productivity. P R Soc Lond B Bio 270:1609–1616Majerus ME, Sloggett JJ, Godeau JF, Hemptinne JL (2007) Interactions between ants and aphidophagous and coccidophagous ladybirds. Popul Ecol 49:15–27Mgocheki N, Addison P (2009) Interference of ants (Hymenoptera: Formicidae) with biological control of the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae). Biol Control 49:180–185Moore D (1988) Agents used for biological control of mealybugs (Pseudococcidae). Biocontrol News Inf 9:209–225Paris CI, Espadaler X (2009) Honeydew collection by the invasive garden ant Lasius neglectus versus the native ant L grandis. Arthropod Plant Interact 3:75–85Pekas A, Tena A, Aguilar A, Garcia-Marí F (2011) Spatio-temporal patterns and interactions with honeydew-producing Hemiptera of ants in a Mediterranean citrus orchard. Agric Forest Entomol 13:89–97Pennacchio F, Strand MR (2006) Evolution of developmental strategies in parasitic Hymenoptera. Annu Rev Entomol 51:233–258Pijls JW, Hofker KD, Staalduinen MJ, van Alphen JJM (1995) Interspecific host discrimination and competition in Apoanagyrus (Epidinocarsis) lopezi and A(E) diversicornis parasitoids of the cassava mealybug Phenacoccus manihoti. Ecol Entomol 20:326–332Robert Y (1987) Dispersion and migration. In: Minks AK, Harrewijn P (eds) Aphids—their biology, natural enemies and control, 1st edn. Elsevier, Amsterdam, The Netherlands, pp 299–313Sandanayaka WRM, Charles JG, Allan DJ (2009) Aspects of the reproductive biology of Pseudaphycus maculipennis (Hym: Encyrtidae), a parasitoid of obscure mealybug, Pseudococcus viburni (Hem: Pseudococcidae). Biol Control 48:30–35Sarkar D (2008) Lattice: multivariate data visualization with R. Springer, New York, USASime KR, Daane KM (2014) Rapid, non-discriminatory oviposition behaviors are favored in mealybug parasitoids when Argentine ants are present. Environ Entomol 43:995–1002Tena A, Garcia-Marí F (2008) Suitability of citricola scale Coccus pseudomagnoliarum (Hemiptera: Coccidae) as host of Metaphycus helvolus (Hymenoptera: Encyrtidae): Influence of host size and encapsulation. Biol Control 46:341–347Tena A, Hoddle CD, Hoddle MS (2013) Competition between honeydew producers in an ant–hemipteran interaction may enhance biological control of an invasive pest. Bull Entomol Res 103:714–723The R Core Team (2011) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austriavan Driesche RG, Belloti A, Herrera CJ, Castello JA (1987a) Host preferences of two encyrtid parasitoids for the Columbian Phenacoccus spp. of cassava mealybugs. Entomol Exp Appl 43:261–266van Driesche RG, Belloti A, Herrera CJ, Castello JA (1987b) Host feeding and ovipositor insertion as sources of mortality in the mealybug Phenacoccus herreni caused by two encyrtids Epidinocarsis diversicornis and Acerophagus coccois. Entomol Exp Appl 44:97–100Vet LE, Dicke M (1992) Ecology of infochemical use by natural enemies in a tritrophic context. Annu Rev Entomol 37:141–172Völkl W, Woodring J, Fischer M, Lorenz MW, Hoffmann KH (1999) Ant-aphid mutualisms: the impact of honeydew production and honeydew sugar composition on ant preferences. Oecologia 118:483–491Wajnberg E (1989) Analysis of variations of handling-time in Trichogramma maidis. Entomophaga 34:397–407Way MJ (1963) Mutualism between ants and honeydew-producing Homoptera. Annu Rev Entomol 8:307–344Weiss MR (2006) Defecation behavior and ecology of insects. Annu Rev Entomol 51:635–661Wyckhuys KAG, Stone L, Desneux N, Hoelmer KA, Hopper KR, Heimpel GE (2008) Parasitism of the soybean aphid Aphis glycines by Binodoxys communis: the role of aphid defensive behavior and parasitoid reproductive performance. Bull Entomol Res 98:361–370Zain-ul-Abdin, Arif MJ, Suhail A, Gogi MD, Arshad M, Wakil W, Abbas SK, Altaf A, Shaina H, Manzoor A (2012) Molecular analysis of the venom of mealybug parasitoid Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae). Pak Entomol 34:189–193Zinna G (1959) Specializzazione entomoparassitica negli Encyrtidae: studio morfologico etologico e fisiologico del Leptomastix dactylopii. Howard Boll Lab agr Filippo Silvestri 18:1–14

    The insecure airway: a comparison of knots and commercial devices for securing endotracheal tubes

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    BACKGROUND: Endotracheal Tubes (ETTs) are commonly secured using adhesive tape, cloth tape, or commercial devices. The objectives of the study were (1) To compare degrees of movement of ETTs secured with 6 different commercial devices and (2) To compare movement of ETTs secured with cloth tape tied with 3 different knots (hitches). METHODS: A 17 cm diameter PVC tube with 14 mm "mouth" hole in the side served as a mannequin. ETTs were subjected to repeated jerks, using a cable and pulley system. Measurements: (1) Total movement of ETTs relative to "mouth" (measure used for devices) (2) Slippage of ETT through securing knot (measure used for knots). RESULTS: Among commercial devices, the Dale(® )showed less movement than other devices, although some differences between devices did not reach significance. Among knots, Magnus and Clove Hitches produced less slippage than the Cow Hitch, but these differences did not reach statistical significance. CONCLUSION: Among devices tested, the Dale(® )was most secure. Within the scope offered by the small sample sizes, there were no statistically significant differences between the knots in this study
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