951 resultados para 4,15-diactoxycscirpenol (4,15-DAS)
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AIMS: The effect of dietary sucrose on insulin resistance and the pathogenesis of diabetes and vascular disease is unclear. We assessed the effect of 5% versus 15% sucrose intakes as part of a weight maintaining, eucaloric diet in overweight/obese subjects.
METHODS: Thirteen subjects took part in a randomised controlled crossover study (M:F 9:4, median age 46 years, range 37-56 years, BMI 31.7±0.9 kg/m(2)). Subjects completed two 6 week dietary periods separated by 4 week washout. Diets were designed to have identical macronutrient profile. Insulin action was assessed using a two-step hyperinsulinaemic euglycaemic clamp; glucose tolerance, vascular compliance, body composition and lipid profiles were also assessed.
RESULTS: There was no change in weight or body composition between diets. There was no difference in peripheral glucose utilization or suppression of endogenous glucose production. Fasting glucose was significantly lower after the 5% diet. There was no demonstrated effect on lipid profiles, blood pressure or vascular compliance.
CONCLUSION: A low-sucrose diet had no beneficial effect on insulin resistance as measured by the euglycaemic glucose clamp. However, reductions in fasting glucose, one hour insulin and insulin area under the curve with the low sucrose diet on glucose tolerance testing may indicate a beneficial effect and further work is required to determine if this is the case. Clinical Trial Registration number ISRCTN50808730.
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Gremlin (Grem1) is a member of the DAN family of secreted bone morphogenetic protein (BMP) antagonists. Bone morphogenetic protein-7 (BMP-7) mediates protective effects during renal fibrosis-associated with diabetes and other renal diseases. The pathogenic mechanism of Grem1 during DN has been suggested to be binding and inhibition of BMP-7. However, the precise interactions between Grem1, BMP-7 and other BMPs have not been accurately defined. Here we show the affinity of Grem1 for BMP-7 is lower than that of BMP-2 and BMP-4, using a combination of surface plasmon resonance and cell culture techniques. Using kidney proximal tubule cells and HEK-293 cell Smad1/5/8 phosphorylation and BMP-dependent gene expression as readout, Grem1 consistently demonstrated a higher affinity for BMP-2>4>7. Cell-associated Grem1 did not inhibit BMP-2 or BMP-4 mediated signalling, suggesting that Grem1-BMP-2 binding occurred in solution, preventing BMP receptor activation. These data suggest that Grem1 preferentially binds to BMP-2 and this may be the dominant complex in a disease situation where levels of Grem1 and BMPs are elevated.
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The Ni-II centre in the cation of the title compound, [Ni(C6H12S3)(2)]Br-2. 4H(2)O, occupies a crystallographic inversion centre and is octahedrally coordinated by six S-donors from two [9]aneS(3) ligands. Ni-S distances range from 2.3749 (16) to 2.4077 (15) Angstrom and S-Ni-S angles where both thia donors belong to the same ligand lie in a narrow range between 88.09 (5) and 88.67 (6)degrees. The water molecules participate in extensive hydrogen bonding with each other and with the Br- anions to form double chains with eight- and 12-membered hydrogen-bonded rings running along the crystallographic a direction.
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Dipeptidyl peptidase 4 (DPP-4) enzymatically inactivates incretin hormones, and DPP-4 inhibitor drugs are clinically approved therapies for type 2 diabetes. The primary substrates of DPP-4 are produced in the intestinal lining and we therefore investigated whether lactobacilli colonizing the gut can inhibit this enzyme. Fifteen Lactobacillus strains (Lb 1-15) from human infant faecal samples were isolated, identified, extracted and screened for inhibitory activity against DPP-4. Activity was compared against Lactobacillus reference strains (Ref 1-7), a Gram positive control (Ctrl 1) and two Gram negative controls (Ctrl 2-3). A range of DPP-4 inhibitory activity was observed (10-32%; P<0.05-0.001). Strains of L. fabifermentans (25%), L. plantarum (12-24%) and L. fermentum (14%) had significant inhibitory activity. However, we also noted that E. coli (Ctrl 2) and S. Typhimurium (Ctrl 3) had the greatest inhibitory activity (30-32%). Contrastingly, some isolates (Lb 12-15) and reference cultures (Ref 1-4) instead of inhibiting DPP-4 actually enhanced it, perhaps indicating the presence of X-prolyl-dipeptidyl-amino-peptidase (PepX). This provides a future rationale for using probiotic bacteria or their components for management of type 2 diabetes via DPP-4 inhibition.
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The spatial location of microorganisms in the soil three-dimensional structure with respect to their substrates plays an important role in the persistence and turnover of natural and xenobiotic organic compounds. To study the effect of spatial location on the mineralisation of 14C-2,4-dichlorophenol (2,4-DCP, 0.15 or 0.31 μmol g-1) and 14C-glucose (2.77 μmol g-1), columns packed with autoclaved soil aggregates (2-5 mm) were used. Using a chloride tracer of water movement, the existence of 'immobile' water, which was by-passed by preferentially flowing 'mobile' water, was demonstrated. By manipulation of the soil moisture content, the substrates were putatively placed to these conceptual hydrological domains (immobile and mobile water). Leaching studies revealed that approximately 1.7 (glucose) and 3.4 (2.4-DCP) times the amount of substrate placed in mobile water was recovered in the first 4 fractions of leachate when compared to substrate placed in immobile water. The marked difference in the breakthrough curves was taken as evidence of successful substrate placement. The 2,4-DCP degrading bacterium, Burkholderia sp. RASCc2, was inoculated in mobile water (1.8-5.2 × 107 cells g-1 soil) and parameters (asymptote, time at maximum rate, calculated maximum rate) describing the mineralisation kinetics of 2,4-DCP and glucose previously added to immobile or mobile water domains were compared, For glucose, there was no significant effect (P > 0.1) of substrate placement on any of the mineralisation parameters. However, substrate placement had a significant effect (P < 0.05) on parameters describing 2,4-DCP mineralisation. In particular, 2,4-DCP added in mobile water was mineralised with a greater maximum rate and with a reduced time at maximum rate when compared to 2,4-DCP added to immobile water. The difference in response between the two test substrates may reflect the importance of sorption in controlling the spatial bioavailability of compounds in soil. © 2002 Elsevier Science Ltd. All rights reserved.
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Interaction of organic xenobiotics with soil water-soluble humic material (WSHM) may influence their environmental fate and bioavailability. We utilized bacterial assays (lux-based toxicity and mineralization by Burkholderia sp. RASC) to assess temporal changes in the bioavailability of [14C]-2,4-dichlorophenol (2,4-DCP) in soil water extracts (29.5 μg mL-1 2,4-DCP; 840.2 μg mL-1 organic carbon). HPLC determined and bioavailable concentrations were compared. Gel permeation chromatography (GPC) was used to confirm the association of a fraction (>50%) of [14C]-2,4-DCP with WSHM. Subtle differences in parameters describing 2,4-DCP mineralization curves were recorded for different soil-2,4-DCP contact times. Problems regarding the interpretation of mineralization data when assessing the bioavailability of toxic compounds are discussed. The lux-bioassay revealed a time-dependent reduction in 2,4-DCP bioavailability: after 7 d, less than 20% was bioavailable. However, GPC showed no quantitative difference in the amount of WSHM-associated 2,4-DCP over this time. These data suggest qualitative changes in the nature of the 2,4-DCP-WSHM association and that associated 2,4-DCP may exert a toxic effect. Although GPC distinguished between free- and WSHM-associated 2,4-DCP, it did not resolve the temporal shift in bioavailability revealed by the lux biosensor. These results stress that assessment of risk posed by chemicals must be considered using appropriate biological assays.
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Although recent decades have seen an improved cure rate for newly diagnosed paediatric acute lymphoplastic leukaemia (ALL), the treatment options for adult ALL, T-cell ALL (T-ALL) and relapsed disease remain poor. We have developed a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds and established their anticancer efficacy in a variety of human tumour cell types. Here, we demonstrate that PBOX-15 inhibits cell growth, and induces G2/M cell cycle arrest and apoptosis in both T-ALL and B-cell ALL (B-ALL) cells. In addition, prior to PBOX-15-induced apoptosis, PBOX-15 decreases ALL cell adhesion, spreading and migration. Concurrently, PBOX-15 differentially down-regulates β1-, β2- and α4-integrin expression in ALL cells and significantly decreases integrin-mediated cell attachment. PBOX-15 interferes with the lateral mobility and clustering of integrins in both B-ALL and T-ALL cells. These data suggest that PBOX-15 is not only effective in inducing apoptosis in ALL cells, but also has the potential to disrupt integrin-mediated adhesion of malignant lymphocytes, which represents a novel avenue for regulating leukaemic cell homing and migration.
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BACKGROUND: We proposed to investigate the radiosensitizing properties of PBOX-15, a novel microtubule-disrupting agent, in a panel of cancer cell lines.
RESULTS: PBOX-15 treatment was associated with significant cell kill and increased radiosensitivity in all three cell lines tested. The number of surviving cells in response to the combined treatment was significantly less than PBOX -15 alone in 22Rv1 cells. In these cells, radiosensitisation correlated with induction of G2/M cell cycle arrest by PBOX-15. The compound sustained its activity and increased HIF-1Α expression under hypoxic conditions. PBOX-15 prevented onset of hypoxia-induced radioresistance in hypoxic prostate cells and reduced the surviving fraction of irradiated hypoxic cells to levels similar to those achieved under aerobic conditions.
METHODS: Clonogenic assays were used to determine sensitivity of a panel of cancer cell lines (22Rv1, A549, U87) to PBOX-15 alone or in combination with a single 2Gy dose fraction. Induction of cell cycle arrest and apoptosis was investigated in 22Rv1 prostate cancer cells. The cytotoxic properties of the compound under hypoxic conditions were correlated with Hypoxia Inducible Factor 1 alpha (HIF-1Α) gene and protein expression levels and its radiosensitisation potential was investigated in hypoxic 22Rv1 using clonogenic assays.
CONCLUSIONS: This preliminary data identifies the potential of PBOX-15 as a novel radiosensitising agent for the management of solid tumours and eradication of hypoxic cells.
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The ordered, directional migration of T-lymphocytes is a key process during immune surveillance, immune response, and development. A novel series of pyrrolo-1,5-benzoxazepines have been shown to potently induce apoptosis in variety of human chemotherapy resistant cancer cell lines, indicating their potential in the treatment of both solid tumors and tumors derived from the hemopoietic system. Pyrrolobenzoxazepine 4-acetoxy-5-(1-naphtyl)naphtho[2,3-b]pyrrolo[1,2-d][1,4]-oxazepine (PBOX-15) has been shown to depolymerize tubulin in vitro and in the MCF7 breast cancer cell line. We hypothesized that this may suggest a role for this compound in modulating integrin-induced T-cell migration, which is largely dependent on the microtubule dynamics. Experiments were performed using human T lymphoma cell line Hut78 and peripheral blood T-lymphocytes isolated from healthy donors. We observed that human T-lymphocytes exposed to PBOX-15 have severely impaired ability to polarize and migrate in response to the triggering stimulus generated via cross-linking of integrin lymphocyte function associated antigen-1 receptor. Here, we show that PBOX-15 can dramatically impair microtubule network via destabilization of tubulin resulting in complete loss of the motile phenotype of T-cells. We demonstrate that PBOX-15 inhibitory mechanisms involve decreased tubulin polymerization and its post-translational modifications. Novel microtubule-targeting effects of PBOX-15 can possibly open new horizons in the treatment of overactive inflammatory conditions as well as cancer and cancer metastatic spreading.
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Background: High risk medications are commonly prescribed to older US patients. Currently, less is known about high risk medication prescribing in other Western Countries, including the UK. We measured trends and correlates of high risk medication prescribing in a subset of the older UK population (community/institutionalized) to inform harm minimization efforts. Methods: Three cross-sectional samples from primary care electronic clinical records (UK Clinical Practice Research Datalink, CPRD) in fiscal years 2003/04, 2007/08 and 2011/12 were taken. This yielded a sample of 13,900 people aged 65 years or over from 504 UK general practices. High risk medications were defined by 2012 Beers Criteria adapted for the UK. Using descriptive statistical methods and regression modelling, prevalence of ‘any’ (drugs prescribed at least once per year) and ‘long-term’ (drugs prescribed all quarters of year) high risk medication prescribing and correlates were determined. Results: While polypharmacy rates have risen sharply, high risk medication prevalence has remained stable across a decade. A third of older (65+) people are exposed to high risk medications, but only half of the total prevalence was long-term (any = 38.4 % [95 % CI: 36.3, 40.5]; long-term = 17.4 % [15.9, 19.9] in 2011/12). Long-term but not any high risk medication exposure was associated with older ages (85 years or over). Women and people with higher polypharmacy burden were at greater risk of exposure; lower socio-economic status was not associated. Ten drugs/drug classes accounted for most of high risk medication prescribing in 2011/12. Conclusions: High risk medication prescribing has not increased over time against a background of increasing polypharmacy in the UK. Half of patients receiving high risk medications do so for less than a year. Reducing or optimising the use of a limited number of drugs could dramatically reduce high risk medications in older people. Further research is needed to investigate why the oldest old and women are at greater risk. Interventions to reduce high risk medications may need to target shorter and long-term use separately.
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Context. The ESA Rosetta spacecraft, currently orbiting around comet 67P/Churyumov-Gerasimenko, has already provided in situ measurements of the dust grain properties from several instruments,particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution.
Aims. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014.
Methods. A Monte Carlo dust tail code, which has already been used to characterise the dust environments of several comets and active asteroids, has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately.
Results. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is α = −3, instead of α = −2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 AU, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 AU. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment.
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Dissertação apresentada à Escola Superior de Educação de Lisboa para a obtenção do grau de Mestre em Intervenção Precoce
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Quarterly newsletter produced by the Iowa Department of Blind, about the information and activities that are on going in the department.
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One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age-standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are affecting the number of adults with diabetes. We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence-defined as fasting plasma glucose of 7.0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs-in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue. We used data from 751 studies including 4,372,000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4.3% (95% credible interval 2.4-7.0) in 1980 to 9.0% (7.2-11.1) in 2014 in men, and from 5.0% (2.9-7.9) to 7.9% (6.4-9.7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28.5% due to the rise in prevalence, 39.7% due to population growth and ageing, and 31.8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target. Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults affected, has increased faster in low-income and middle-income countries than in high-income countries. Wellcome Trust.