169 research outputs found

    Relationship between the magnitude of intraocular pressure during an episode of acute elevation and retinal damage four weeks later in rats

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    PURPOSE: To determine relationship between the magnitude of intraocular pressure (IOP) during a fixed-duration episode of acute elevation and the loss of retinal function and structure 4 weeks later in rats. METHODS: Unilateral elevation of IOP (105 minutes) was achieved manometrically in adult Brown Norway rats (9 groups; n = 4 to 8 each, 10-100 mm Hg and sham control). Full-field ERGs were recorded simultaneously from treated and control eyes 4 weeks after IOP elevation. Scotopic ERG stimuli were white flashes (-6.04 to 2.72 log cd.s.m(-2)). Photopic ERGs were recorded (1.22 to 2.72 log cd.s.m(-2)) after 15 min of light adaptation (150 cd/m(2)). Relative amplitude (treated/control, %) of ERG components versus IOP was described with a cummulative normal function. Retinal ganglion cell (RGC) layer density was determined post mortem by histology. RESULTS: All ERG components failed to recover completely normal amplitudes by 4 weeks after the insult if IOP was 70 mmHg or greater during the episode. There was no ERG recovery at all if IOP was 100 mmHg. Outer retinal (photoreceptor) function demonstrated the least sensitivity to prior acute IOP elevation. ERG components reflecting inner retinal function were correlated with post mortem RGC layer density. CONCLUSIONS: Retinal function recovers after IOP normalization, such that it requires a level of acute IOP elevation approximately 10 mmHg higher to cause a pattern of permanent dysfunction similar to that observed during the acute event. There is a 'threshold' for permanent retinal functional loss in the rat at an IOP between 60 and 70 mmHg if sustained for 105 minutes or more

    On the geometry of C^3/D_27 and del Pezzo surfaces

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    We clarify some aspects of the geometry of a resolution of the orbifold X = C3/D_27, the noncompact complex manifold underlying the brane quiver standard model recently proposed by Verlinde and Wijnholt. We explicitly realize a map between X and the total space of the canonical bundle over a degree 1 quasi del Pezzo surface, thus defining a desingularization of X. Our analysis relys essentially on the relationship existing between the normalizer group of D_27 and the Hessian group and on the study of the behaviour of the Hesse pencil of plane cubic curves under the quotient.Comment: 23 pages, 5 figures, 2 tables. JHEP style. Added references. Corrected typos. Revised introduction, results unchanged

    A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis

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    Honey bee colonies are subject to numerous pathogens and parasites. Interaction among multiple pathogens and parasites is the proposed cause for Colony Collapse Disorder (CCD), a syndrome characterized by worker bees abandoning their hive. Here we provide the first documentation that the phorid fly Apocephalus borealis, previously known to parasitize bumble bees, also infects and eventually kills honey bees and may pose an emerging threat to North American apiculture. Parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, we confirmed that phorids that emerged from honey bees and bumble bees were the same species. Microarray analyses of honey bees from infected hives revealed that these bees are often infected with deformed wing virus and Nosema ceranae. Larvae and adult phorids also tested positive for these pathogens, implicating the fly as a potential vector or reservoir of these honey bee pathogens. Phorid parasitism may affect hive viability since 77% of sites sampled in the San Francisco Bay Area were infected by the fly and microarray analyses detected phorids in commercial hives in South Dakota and California's Central Valley. Understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD

    Parasite Lost: Chemical and Visual Cues Used by Pseudacteon in Search of Azteca instabilis

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    An undescribed species of phorid fly (genus: Pseudacteon) parasitizes the ant Azteca instabilis F Smith, by first locating these ants through the use of both chemical and visual cues. Experiments were performed in Chiapas, Mexico to examine a) the anatomical source of phorid attractants, b) the specific chemicals produced that attract phorids, and c) the nature of the visual cues used by phorids to locate the ants. We determined that phorid-attracting chemicals were present within the dorsal section of the abdomen, the location of the pygidial gland. Further experiments indicate that a pygidial gland compound, 1-acetyl-2-methylcyclopentane, is at least partially responsible for attracting phorid flies to their host. Finally, although visual cues such as movement were important for host location, size and color of objects did not influence the frequency with which phorids attacked moving targets

    DreamTel; Diabetes risk evaluation and management tele-monitoring study protocol

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    <p>Abstract</p> <p>Background</p> <p>The rising prevalence of type 2 diabetes underlines the importance of secondary strategies for the prevention of target organ damage. While access to diabetes education centers and diabetes intensification management has been shown to improve blood glucose control, these services are not available to all that require them, particularly in rural and northern areas. The provision of these services through the Home Care team is an advance that can overcome these barriers. Transfer of blood glucose data electronically from the home to the health care provider may improve diabetes management.</p> <p>Methods and design</p> <p>The study population will consist of patients with type 2 diabetes with uncontrolled A1c levels living on reserve in the Battlefords region of Saskatchewan, Canada. This pilot study will take place over three phases. In the first phase over three months the impact of the introduction of the Bluetooth enabled glucose monitor will be assessed. In the second phase over three months, the development of guidelines based treatment algorithms for diabetes intensification will be completed. In the third phase lasting 18 months, study subjects will have diabetes intensification according to the algorithms developed.</p> <p>Discussion</p> <p>The first phase will determine if the use of the Bluetooth enabled blood glucose devices which can transmit results electronically will lead to changes in A1c levels. It will also determine the feasibility of recruiting subjects to use this technology. The rest of the Diabetes Risk Evaluation and Management Tele-monitoring (DreamTel) study will determine if the delivery of a diabetes intensification management program by the Home Care team supported by the Bluetooth enabled glucose meters leads to improvements in diabetes management.</p> <p>Trial Registration</p> <p>Protocol NCT00325624</p

    Experiencing neutropenia: Quality of life interviews with adult cancer patients

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    BACKGROUND: Neutropenia is a common toxicity in chemotherapy but detailed information about how neutropenia is associated with changes in patients' quality of life is not readily available. This prospective study interviewed patients with grade 4 neutropenia to provide qualitative information on patients' experience of developing and coping with grade 4 neutropenia during a cycle of chemotherapy. METHODS: A sample of 34 patients who developed grade 4 neutropenia during the first cycle of chemotherapy completed a total of 100 structured clinical interviews. Interviews were transcribed, and 2 raters inductively developed 5 broad categories comprising 80 specific complaint domains nominated by patients. Thirty-five patient-nominated problems were mentioned in 5% or more of the interviews. RESULTS: Fatigue was the most common physical symptom. Interference in daily routine, negative self-evaluation, negative emotion, and social isolation were other common complaints associated with neutropenia. CONCLUSION: Neutropenia is associated with a number of negative experiences among cancer patients undergoing chemotherapy, and these negative experiences have an adverse effect on the patient's quality of life. Oncology nurses can play a key role in helping patients manage adverse effects to maintain their quality of life

    Cytogenetic analysis of three species of Pseudacteon (Diptera, Phoridae) parasitoids of the fire ants using standard and molecular techniques

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    Pseudacteon flies, parasitoids of worker ants, are being intensively studied as potentially effective agents in the biological control of the invasive pest fire ant genus Solenopsis (Hymenoptera: Formicidae). This is the first attempt to describe the karyotype of P. curvatus Borgmeier, P. nocens Borgmeier and P. tricuspis Borgmeier. The three species possess 2n = 6; chromosomes I and II were metacentric in the three species, but chromosome pair III was subtelocentric in P. curvatus and P. tricuspis, and telocentric in P. nocens. All three species possess a C positive band in chromosome II, lack C positive heterochromatin on chromosome I, and are mostly differentiated with respect to chromosome III. P. curvatus and P. tricuspis possess a C positive band, but at different locations, whereas this band is absent in P. nocens. Heterochromatic bands are neither AT nor GC rich as revealed by fluorescent banding. In situ hybridization with an 18S rDNA probe revealed a signal on chromosome II in a similar location to the C positive band in the three species. The apparent lack of morphologically distinct sex chromosomes is consistent with proposals of environmental sex determination in the genus. Small differences detected in chromosome length and morphology suggests that chromosomes have been highly conserved during the evolutionary radiation of Pseudacteon. Possible mechanisms of karyotype evolution in the three species are suggested

    Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC

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    We present the first results of meson production in the K^+K^- decay channel from Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity by the PHENIX detector at RHIC. Precision resonance centroid and width values are extracted as a function of collision centrality. No significant variation from the PDG accepted values is observed. The transverse mass spectra are fitted with a linear exponential function for which the derived inverse slope parameter is seen to be constant as a function of centrality. These data are also fitted by a hydrodynamic model with the result that the freeze-out temperature and the expansion velocity values are consistent with the values previously derived from fitting single hadron inclusive data. As a function of transverse momentum the collisions scaled peripheral.to.central yield ratio RCP for the is comparable to that of pions rather than that of protons. This result lends support to theoretical models which distinguish between baryons and mesons instead of particle mass for explaining the anomalous proton yield.Comment: 326 authors, 24 pages text, 23 figures, 6 tables, RevTeX 4. To be submitted to Physical Review C as a regular article. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Curcumin-induced HDAC inhibition and attenuation of medulloblastoma growth in vitro and in vivo

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    <p>Abstract</p> <p>Background</p> <p>Medulloblastoma is the most common brain tumor in children, and its prognosis is worse than for many other common pediatric cancers. Survivors undergoing treatment suffer from serious therapy-related side effects. Thus, it is imperative to identify safer, effective treatments for medulloblastoma. In this study we evaluated the anti-cancer potential of curcumin in medulloblastoma by testing its ability to induce apoptosis and inhibit tumor growth <it>in vitro </it>and <it>in vivo </it>using established medulloblastoma models.</p> <p>Methods</p> <p>Using cultured medulloblastoma cells, tumor xenografts, and the Smo/Smo transgenic medulloblastoma mouse model, the antitumor effects of curcumin were tested <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>Curcumin induced apoptosis and cell cycle arrest at the G2/M phase in medulloblastoma cells. These effects were accompanied by reduced histone deacetylase (HDAC) 4 expression and activity and increased tubulin acetylation, ultimately leading to mitotic catastrophe. In <it>in vivo </it>medulloblastoma xenografts, curcumin reduced tumor growth and significantly increased survival in the Smo/Smo transgenic medulloblastoma mouse model.</p> <p>Conclusions</p> <p>The <it>in vitro </it>and <it>in vivo </it>data suggest that curcumin has the potential to be developed as a therapeutic agent for medulloblastoma.</p

    Fire Ant Decapitating Fly Cooperative Release Programs (1994–2008): Two Pseudacteon Species, P. tricuspis and P. curvatus, Rapidly Expand Across Imported Fire Ant Populations in the Southeastern United States

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    Natural enemies of the imported fire ants, Solenopsis invicta Buren S. richteri Forel (Hymenoptera: Formicidae), and their hybrid, include a suite of more than 20 fire ant decapitating phorid flies from South America in the genus Pseudacteon. Over the past 12 years, many researchers and associates have cooperated in introducing several species as classical or self-sustaining biological control agents in the United States. As a result, two species of flies, Pseudacteon tricuspis Borgmeier and P. curvatus Borgmeier (Diptera: Phoridae), are well established across large areas of the southeastern United States. Whereas many researchers have published local and state information about the establishment and spread of these flies, here distribution data from both published and unpublished sources has been compiled for the entire United States with the goal of presenting confirmed and probable distributions as of the fall of 2008. Documented rates of expansion were also used to predict the distribution of these flies three years later in the fall of 2011. In the fall of 2008, eleven years after the first successful release, we estimate that P. tricuspis covered about 50% of the fire ant quarantined area and that it will occur in almost 65% of the quarantine area by 2011. Complete coverage of the fire ant quarantined area will be delayed or limited by this species' slow rate of spread and frequent failure to establish in more northerly portions of the fire ant range and also, perhaps, by its preference for red imported fire ants (S. invicta). Eight years after the first successful release of P. curvatus, two biotypes of this species (one biotype occurring predominantly in the black and hybrid imported fire ants and the other occurring in red imported fire ants) covered almost 60% of the fire ant quarantined area. We estimate these two biotypes will cover almost 90% of the quarantine area by 2011 and 100% by 2012 or 2013. Strategic selection of several distributional gaps for future releases will accelerate complete coverage of quarantine areas. However, some gaps may be best used for the release of additional species of decapitating flies because establishment rates may be higher in areas without competing species
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