407 research outputs found

    Analysis of 13 C and 14 C labeling in pyruvate and lactate in tumor and blood of lymphoma-bearing mice injected with 13 C- and 14 C-labeled pyruvate

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    Measurements of hyperpolarized 13C label exchange between injected [1‐13C]pyruvate and the endogenous tumor lactate pool can give an apparent first‐order rate constant for the exchange. The determination of the isotope flux, however, requires an estimate of the labeled pyruvate concentration in the tumor. This was achieved here by measurement of the tumor uptake of [1‐14C]pyruvate, which showed that <2% of the injected pyruvate reached the tumor site. Multiplication of this estimated labeled pyruvate concentration in the tumor with the apparent first‐order rate constant for hyperpolarized 13C label exchange gave an isotope flux that showed good agreement with a flux determined directly by the injection of non‐polarized [3‐13C]pyruvate, rapid excision of the tumor after 30 s and measurement of 13C‐labeled lactate concentrations in tumor extracts. The distribution of labeled lactate between intra‐ and extracellular compartments and the blood pool was investigated by imaging, by measurement of the labeled lactate concentration in blood and tumor, and by examination of the effects of a gadolinium contrast agent and a lactate transport inhibitor on the intensity of the hyperpolarized [1‐13C]lactate signal. These measurements showed that there was significant export of labeled lactate from the tumor, but that labeled lactate in the blood pool produced by the injection of hyperpolarized [1‐13C]pyruvate showed only relatively low levels of polarization. This study shows that measurements of hyperpolarized 13C label exchange between pyruvate and lactate in a murine tumor model can provide an estimate of the true isotope flux if the concentration of labeled pyruvate that reaches the tumor can be determined

    Transverse momentum dependence in gluon distribution and fragmentation functions

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    We investigate the twist two gluon distribution functions for spin 1/2 hadrons, emphasizing intrinsic transverse momentum of the gluons. These functions are relevant in leading order in the inverse hard scale in scattering processes such as inclusive leptoproduction or Drell-Yan scattering, or more general in hard processes in which at least two hadrons are involved. They show up in azimuthal asymmetries. For future estimates of such observables, we discuss specific bounds on these functions.Comment: 14 pages, revtex, 7 Postscript figure

    Germinação E Reindução Da Tolerância à Dessecação Em Sementes De Senna Multijuga (rich.) Irwin Et Barn

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    The aims of this study were to verify the effects of different tests in the overcoming dormancy, excellent germination terms, as light and temperature, and the possibility of re-induction of desiccation tolerance in Senna multijuga seeds. We evaluated two tests for overcoming dormancy: immersion in water with an initial temperature of 100ºC (hot water) and immersion in water at a constant temperature at 100ºC for 20 seconds (boiling water), both treatments followed by rest out of the heating for 24 hours. For the germination test, we evaluated 25ºC, 30ºC (constant) and 20-30ºC (alternate), in the presence and absence of light. For the re-induction of desiccation tolerance, we selected seeds germinated with 1, 2, 3 and 4mm of radicle length. We submitted the germinated seeds to the follow treatments: no incubation, incubation in polyethylene glycol (PEG6000) at the -1,4, -1,7 and -2,0MPa; incubation in PEG -1,4MPa + ABA at the concentrations of 1, 10 and 100μM. The tests followed a completely randomized design (DIC) using 4 repetitions of 25 seeds. The overcoming dormancy using hot water provided the best germination (65%). The Senna multijuga seeds are not photoblastic required, but in light conditions the germination was higher. We observed the resumption of the radicle growth in germinated seeds of up to 3mm length. © 2016, Universidade Federal de Santa Maria. All rights reserved.2641133114

    Modulation of the oxidative stress in malaria infection by clotrimazole

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    Antimycotic clotrimazole (CTZ) has demonstrated remarkable activity against Plasmodium falciparum in vitro and in vivo. Hemoglobin degradation by Plasmodium parasites makes amino acids available for protein synthesis, inducing oxidative stress in infected cells and producing free heme. These events represent biochemical targets for potential antimalarials. In this study, we have tested the ability of CTZ to modify the oxidative status in Plasmodium berghei-infected erythrocytes. After hemolysis, activities of superoxide dismutase (SOD), catalase (CAT), glutathione cycle and NADPH+H+-producing dehydrogenases were investigated using UV-visible spectrophotometry. Thiobarbituric acid reactive substances (TBARS) were evaluated as a marker of lipid damage. Results showed that CTZ significantly decreased the overall activity of 6-phosphagluconate dehydrogenase (6PGD) compared to infected and non-treated cells; consequently, the glutathione cycle was inhibited, leaving the parasite vulnerable to the oxidative stress originating from hemoglobin degradation. As a compensatory response, CTZ prevented some loss of SOD and CAT activities in infected cells. The infection triggered lipid peroxidation in erythrocytes, which was decreased by CTZ. These results suggest the presence of a redox unbalance in cells treated with CTZ, discussing a possible effect of this compound disturbing the oxidative status in a Plasmodium berghei-infection.O antifúngico clotrimazol (CTZ) tem demonstrado notável atividade contra Plasmodium falciparum. A degradação da hemoglobina por Plasmodium para a obtenção dos aminoácidos necessários à síntese protéica induz estresse oxidativo em eritrócitos devido à liberação de hemos oxidantes. Estes eventos representam alvos bioquímicos para a produção de antimaláricos potenciais. Neste estudo, testamos a capacidade do CTZ para modificar o estado oxidativo em eritrócitos infectados com Plasmodium berghei. Depois da hemólise, as atividades da superóxido dismutase (SOD), catalase (CAT), desidrogenases produtoras de NADPH+H+ e do ciclo de glutationa (GSH) foram investigados. A produção das espécies reativas ao ácido tiobarbitúrico (TBARS) foi avaliada como marcador de dano lipídico. Os resultados mostraram que o CTZ diminuiu a atividade da 6-fosfogliconato desidrogenase (6PGD), em comparação com eritrócitos infectados e não tratados. Consequentemente, o ciclo da GSH foi inibido, tornando os parasitas vulneráveis ao estresse oxidativo resultante da degradação da hemoglobina. Como resposta compensatória, CTZ impediu a perda de atividade da SOD e CAT nas células infectadas. A infecção induz peroxidação lipídica nos eritrócitos, sendo esta diminuída pelo CTZ. Estes resultados sugerem a existência de desequilíbrio redox nas células tratadas com CTZ, interferindo, assim, com o estado oxidativo verificado durante a infecção malárica

    Ankle-brachial index as a predictor of coronary disease events in elderly patients submitted to coronary angiography

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    OBJECTIVES: To correlate the importance of the ankle-brachial index in terms of cardiovascular morbimortalityand the extent of coronary arterial disease amongst elderly patients without clinical manifestations of lowerlimb peripheral arterial disease.METHODS: We analyzed prospective data from 100 patients over 65 years of age with coronary arterial disease,as confirmed by coronary angiography, and with over 70% stenosis of at least one sub-epicardial coronaryartery. We measured the ankle-brachial index immediately after coronary angiography, and a value of ,0.9was used to diagnose peripheral arterial disease.RESULTS: The patients’ average age was 77.4 years. The most prevalent risk factor was hypertension (96%), andthe median late follow-up appointment was 28.9 months. The ankle-brachial index was ,0.9 in 47% of thepatients, and a low index was more prevalent in patients with multiarterial coronary disease compared topatients with uniarterial disease in the same group. Using a bivariate analysis, only an ankle-brachial index of,0.9 was a strong predictive factor for cardiovascular events, thereby increasing all-cause deaths and fatal andnon-fatal acute myocardial infarctions two- to three-fold.CONCLUSION: In elderly patients with documented coronary disease, a low ankle-brachial index (,0.9) wasassociated with the severity and extent of coronary arterial disease, and in late follow-up appointments, a lowindex was correlated with an increase in the occurrence of major cardiovascular events

    Branes, Anti-Branes and Brauer Algebras in Gauge-Gravity duality

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    We propose gauge theory operators built using a complex Matrix scalar which are dual to brane-anti-brane systems in AdS5×S5AdS_5 \times S^5 , in the zero coupling limit of the dual Yang-Mills. The branes involved are half-BPS giant gravitons. The proposed operators dual to giant-anti-giant configurations satisfy the appropriate orthogonality properties. Projection operators in Brauer algebras are used to construct the relevant multi-trace Matrix operators. These are related to the ``coupled representations'' which appear in 2D Yang-Mills theory. We discuss the implications of these results for the quantum mechanics of a complex matrix model, the counting of non-supersymmetric operators and the physics of brane-anti-brane systems. The stringy exclusion principle known from the properties of half-BPS giant gravitons, has a new incarnation in this context. It involves a qualitative change in the map between brane-anti-brane states to gauge theory operators. In the case of a pair of sphere giant and anti-giant this change occurs when the sum of the magnitudes of their angular momenta reaches NN.Comment: 52 pages, 10 figure

    Giant Gravitons - with Strings Attached (III)

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    We develop techniques to compute the one-loop anomalous dimensions of operators in the N=4{\cal N}=4 super Yang-Mills theory that are dual to open strings ending on boundstates of sphere giant gravitons. Our results, which are applicable to excitations involving an arbitrary number of open strings, generalize the single string results of hep-th/0701067. The open strings we consider carry angular momentum on an S3^3 embedded in the S5^5 of the AdS5×_5\timesS5^5 background. The problem of computing the one loop anomalous dimensions is replaced with the problem of diagonalizing an interacting Cuntz oscillator Hamiltonian. Our Cuntz oscillator dynamics illustrates how the Chan-Paton factors for open strings propagating on multiple branes can arise dynamically.Comment: 66 pages; v2: improved presentatio

    Facilitators of and barriers to lifestyle support and eHealth solutions: interview study among health care professionals working in cardiac care

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    Background: Cardiovascular diseases (CVDs) pose a significant health threat and reduce both people's life expectancy and quality of life. Healthy living is a key component in the effective prevention and treatment of CVD. However, health care professionals (HCPs) experience difficulties in supporting lifestyle changes among their patients. eHealth can provide a solution to these barriers.Objective: This study aims to provide insights into the factors HCPs find important in the support of patients with CVD in the uptake of and adherence to a healthy lifestyle and the perceived facilitators of and barriers to using eHealth to provide lifestyle support to patients with CVD.Methods: In-depth interviews were conducted with 16 Dutch HCPs specializing in lifestyle support in cardiac care.Results: We identified 13 themes, of which the first 12 concerned lifestyle support in general and were related to intervention, patient, or health care. Throughout these themes, the use of eHealth reoccurred as a potential facilitator of or solution to barriers to lifestyle support. Our final theme specifically concerned barriers to the adoption and usability of eHealth.Conclusions: HCPs do recognize the potential advantages of eHealth while experiencing barriers to using digital tools. Incorporating their needs and values in the development of lifestyle support programs, especially eHealth, could increase their use and lead to a more widespread adoption of eHealth into health care.Cardiolog
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