16 results on '"R. Beltrán"'
Search Results
2. Simulation of the ion beam‐plasma interaction processes for point‐like ions in doped DT plasmas
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G. Espinosa, Pablo R. Beltrán, Manuel D. Barriga-Carrasco, J.M. Gil, and Rafael L. Rodríguez
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Materials science ,Ion beam ,0103 physical sciences ,Doping ,Point (geometry) ,Plasma ,Atomic physics ,010306 general physics ,01 natural sciences ,Spectroscopy ,010305 fluids & plasmas ,Ion - Published
- 2019
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3. Monochromatic and mean radiative properties of astrophysical plasma mixtures in nonlocal thermodynamic equilibrium regime
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G. Espinosa, J.M. Gil, Rafael L. Rodríguez, and Pablo R. Beltrán
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Imagination ,Physics ,Thesaurus (information retrieval) ,Chemical substance ,Thermodynamic equilibrium ,media_common.quotation_subject ,01 natural sciences ,Computational physics ,0103 physical sciences ,Radiative transfer ,Astrophysical plasma ,Monochromatic color ,010306 general physics ,010303 astronomy & astrophysics ,Spectroscopy ,media_common - Published
- 2018
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4. Occurrence ofMonosporascus cannonballusin Watermelon Fields in Tunisia and Factors Associated with Ascospore Density in Soil
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Antonio Vicent, José García-Jiménez, Paloma Abad-Campos, Josep Armengol, Naima Boughalleb, Ibtissem Ben Salem, R. Beltrán, and Ana Perez Sierra
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biology ,Citrullus lanatus ,Physiology ,Monosporascus cannonballus ,Growing season ,Plant Science ,Vertisol ,biology.organism_classification ,Population density ,Crop ,Agronomy ,Ascospore ,Soil water ,Genetics ,Agronomy and Crop Science - Abstract
Surveys of 11 watermelon fields throughout production areas of this crop in southern and central regions in Tunisia were conducted in 2007 to determine the aetiology and distribution of watermelon vine decline. Monosporascus cannonballus was isolated from diseased roots in all surveyed fields. All the isolates were identified according to morphological features and confirmed by amplification of a fragment of the ITS region with specific primers. Ascospores of M. cannonballus were recovered from soil in all watermelon fields surveyed and the average population densities ranged from 3.65 to 10.14 ascospores per g of soil. Multiple linear regression analysis revealed that only four of the crop and soil factors evaluated had a significant correlation with ascospore density at the end of the growing season: vertisol vs. other soils, disease incidence, percentage of clay and pH. The pH of the soil showed a strong significant negative linear relationship with ascospore density, while the other three factors correlated positively.
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- 2010
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5. Joint density of states of nanostructures: an application to porous silicon
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Marcela R. Beltrán, Chumin Wang, M. Cruz, and Julia Tagüeña-Martínez
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Reciprocal lattice ,symbols.namesake ,Nanostructure ,Condensed matter physics ,Hydrogen ,chemistry ,symbols ,Density of states ,chemistry.chemical_element ,Crystalline silicon ,Porous silicon ,Hamiltonian (quantum mechanics) ,Basis set - Abstract
In this work the electronic interband transitions in porous silicon are studied. The calculation is performed using a supercell model with a tight-binding Hamiltonian, where an atomic-orbital sp3s* basis set is used. The pores are modelled as empty columns, digged in a crystalline silicon structure, and then passivated with hydrogen atoms. The effects of disorder in porous silicon are considered by introducing a random perturbative potential into the Hamiltonian, which produces non-vertical interband transitions in the reciprocal space. Such transitions occur in an interval inversely proportional to the electronic localization length. Finally, a comparative analysis of the optical absorption coefficient is performed by means of vertical, non-vertical transition, and the joint density of states (JDOS). (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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- 2005
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6. Quantification of Monosporascuscannonballus Ascospores in Muskmelon Fields in Eastern Spain
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Josep Armengol, José García-Jiménez, R. Beltrán, and Antonio Vicent
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Canopy ,Vine ,biology ,Physiology ,Monosporascus cannonballus ,Plant Science ,biology.organism_classification ,Mediterranean Basin ,Horticulture ,Ascospore ,Soil water ,Botany ,Genetics ,Agronomy and Crop Science ,Cucurbitaceae - Abstract
The populations of Monosporascus cannonballus ascospores in the soils of 14 muskmelon fields throughout muskmelon production areas of Comunidad Valenciana (eastern Spain) were quantified from 2002 to 2003. The fields were surveyed in July, at the end of the cropping season, when plants approached maturity and symptoms of vine decline in the canopy appeared as patches of wilted or dead plants. Ascospores were recovered from all muskmelon fields surveyed. The average soil populations ranged from 1.54 to 6.33 per g of soil and the number of ascospores within a soil sample ranged from 0.50 to 16.20 ascospores/g of soil. This is the first detailed report on ascospore populations of M. cannonballus in muskmelon fields from a cucurbit-growing area in Spain and the Mediterranean basin.
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- 2007
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7. ChemInform Abstract: H2O Nucleation Around Au+
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Shiv N. Khanna, Patrizia Calaminici, Marcela R. Beltrán, Andres M. Koester, and J. Ulises Reveles
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Chemistry ,Nucleation ,Nanotechnology ,General Medicine - Published
- 2008
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8. A South American Experience With Postoperative Complications Following Chest Wall Reconstruction for Neoplasms.
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Carvajal C, Ramirez AM, Guerrero-Macías S, Beltrán R, Buitrago R, and Carreño J
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- Female, Humans, Middle Aged, Postoperative Complications epidemiology, Postoperative Complications etiology, Retrospective Studies, South America, Plastic Surgery Procedures, Thoracic Neoplasms surgery, Thoracic Wall surgery
- Abstract
Background: This study aims to report postoperative complications of chest wall reconstructions due to resections of primary or secondary neoplasms in a South American cancer institution and their association with prosthesis reconstruction., Materials and Methods: We retrospectively reviewed clinical records of patients with primary or secondary chest wall neoplasms who underwent resection and reconstruction between November 2008 and October 2018 at the Instituto Nacional de Cancerología, Bogota, Colombia., Results: A total of 77 patients were analyzed, 50 were women (64.9%), and the median age was 45.8 years. There were 22(28.6%) sternal resections and 55(71.4%) costal resections. Prosthetic material was used in 14(18.2%) sternal and 37(48.1%) costal reconstructions. There were 26(33.7%) early postoperative complications and 16(20.8%) reinterventions. Infections were observed in 12(15.6%) patients and 4(5.2%) patients developed respiratory complications. 33.3% of all the early infections were presented in patients with methyl methacrylate (MMA) reconstructions and the same percentage in those with titanium plates. There were six (7.8%) late complications and five were related to prosthetic material extrusion, all required prosthetic material removal. The mean overall survival was 77,3 months (SD = 8 months), and 1-year and 5-year overall survival was 85% and 61%, respectively., Conclusions: Infections were the more frequent postoperative complications in chest wall reconstructions. The use of either MMA or titanium plates was not related to early postoperative complications, although MMA reconstructions developed higher late complications and required prosthetic material removal., (© 2021. Société Internationale de Chirurgie.)
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- 2021
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9. Activity and selectivity cliffs for DPP-IV inhibitors: Lessons we can learn from SAR studies and their application to virtual screening.
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Ojeda-Montes MJ, Gimeno A, Tomas-Hernández S, Cereto-Massagué A, Beltrán-Debón R, Valls C, Mulero M, Pujadas G, and Garcia-Vallvé S
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- Amino Acid Sequence, Animals, Binding Sites, Dipeptidyl Peptidase 4 chemistry, Dipeptidyl Peptidase 4 metabolism, Dipeptidyl-Peptidase IV Inhibitors analysis, Humans, Structure-Activity Relationship, Dipeptidyl-Peptidase IV Inhibitors chemistry, Dipeptidyl-Peptidase IV Inhibitors pharmacology, Drug Evaluation, Preclinical, User-Computer Interface
- Abstract
The inhibition of dipeptidyl peptidase-IV (DPP-IV) has emerged over the last decade as one of the most effective treatments for type 2 diabetes mellitus, and consequently (a) 11 DPP-IV inhibitors have been on the market since 2006 (three in 2015), and (b) 74 noncovalent complexes involving human DPP-IV and drug-like inhibitors are available at the Protein Data Bank (PDB). The present review aims to (a) explain the most important activity cliffs for DPP-IV noncovalent inhibition according to the binding site structure of DPP-IV, (b) explain the most important selectivity cliffs for DPP-IV noncovalent inhibition in comparison with other related enzymes (i.e., DPP8 and DPP9), and (c) use the information deriving from this activity/selectivity cliff analysis to suggest how virtual screening protocols might be improved to favor the early identification of potent and selective DPP-IV inhibitors in molecular databases (because they have not succeeded in identifying selective DPP-IV inhibitors with IC
50 ≤ 100 nM). All these goals are achieved with the help of available homology models for DPP8 and DPP9 and an analysis of the structure-activity studies used to develop the noncovalent inhibitors that form part of some of the complexes with human DPP-IV available at the PDB., (© 2018 Wiley Periodicals, Inc.)- Published
- 2018
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10. The relevance of the association between inflammation and atrial fibrillation.
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Alegret JM, Aragonès G, Elosua R, Beltrán-Debón R, Hernández-Aguilera A, Romero-Menor C, Camps J, and Joven J
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- Adult, Atrial Fibrillation genetics, C-Reactive Protein genetics, Case-Control Studies, Chemokine CCL2 genetics, Enzyme-Linked Immunosorbent Assay, Female, Humans, Inflammation genetics, Male, Middle Aged, Polymorphism, Genetic, Regression Analysis, Risk Factors, Atrial Fibrillation blood, C-Reactive Protein metabolism, Chemokine CCL2 blood, Inflammation blood
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Background: The relevance of the association between inflammation and atrial fibrillation (AF) is not firmly established. The clinical importance is considerable because inflammation is usually not targeted as a treatment option, minimizing a probable benefit., Materials and Methods: We have used a case-control study with a Mendelian randomization rationale to assess whether proposed risk factors that have a genetic component and are readily detected in circulating blood are causally related to AF. The studied variables were C-reactive protein (CRP) and a representative of the chemokine system, the monocyte chemoattractant protein-1 (CCL2)., Results: Plasma CRP and CCL2 concentrations were significantly higher in AF patients than in the unaffected population. However, when segregated between paroxysmal and permanent, the difference for CRP was only observed in patients with a permanent condition. Plasma CCL2 was raised in both subgroups. Confounding factors were carefully considered, and multivariable analyses revealed that circulating CCL2 was significant and CRP was negligible to explain the presence of AF. The duration of the episode also bore a significant predictive value. Odd ratios for AF as a function of genotype did not differ from 1·0 for any of the individual CRP and CCL2 polymorphisms, or any combinations., Conclusions: Elevated plasma CRP concentration per se does not increase atrial fibrillation risk. Values obtained for CCL2 suggest that inflammation is probably a consequence of AF. Our data also suggest that the effect of the duration of the episode should be further studied in the assessment of the actual role of inflammation., (© 2013 The Authors. European Journal of Clinical Investigation © 2013 Stichting European Society for Clinical Investigation Journal Foundation.)
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- 2013
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11. Metformin: a cheap and well-tolerated drug that provides benefits for viral infections.
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Joven J, Menéndez JA, Fernandez-Sender L, Espinel E, Rull A, Beltrán-Debón R, Rodríguez-Gallego E, Riera-Borrull M, Pedro-Botet J, Alonso-Villaverde C, Camps J, and Aragonès G
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- Adult, Ataxia Telangiectasia Mutated Proteins, Cell Cycle Proteins genetics, Cytomegalovirus isolation & purification, DNA-Binding Proteins genetics, Female, Genotype, HIV Infections virology, Humans, Male, Middle Aged, Protein Serine-Threonine Kinases genetics, Tumor Suppressor Proteins genetics, Coinfection metabolism, Cytomegalovirus Infections metabolism, HIV Infections metabolism, Hypoglycemic Agents therapeutic use, Insulin Resistance genetics, Metformin therapeutic use
- Abstract
Objectives: Insulin resistance in viral infections is common. We have explored the effectiveness of metformin for alleviating insulin resistance in HIV-infected patients and assessed the relevance of the ataxia-telangiectasia mutated (ATM) rs11212617 variant in the clinical response with the rationale that metformin modulates cellular bioenergetics in an ATM-dependent process., Methods: HIV-infected patients (n = 385) were compared with controls recruited from the general population (n = 300) with respect to the genotype distribution of the ATM rs11212617 variant and its influence on selected metabolic and inflammatory variables. We also followed up a subset of male patients with HIV and hepatitis C virus (HCV) coinfection (n = 47) who were not receiving antiviral treatment and for whom metformin was prescribed for insulin resistance, which tends to have a higher incidence and severity in coinfected patients., Results: Among the HIV-infected patients, human cytomegalovirus (91.9%) and HCV (62.3%) coinfections were frequent. Selected metabolic and/or inflammatory variables were significantly altered in infected patients. Treatment with metformin in HIV and HCV coinfected patients was well tolerated and significantly increased the sensitivity of peripheral tissues to insulin. The minor allele (C) of the rs11212617 variant was associated with treatment success and may affect the course of insulin resistance in response to metformin (odds ratio 1.21; 95% confidence interval 1.07-1.39; P = 0.005). There were no differences between treated and untreated patients in viral loads or variables measuring immune defence, indicating that toxicity is unlikely., Conclusions: We provide novel data suggesting that identification of the ATM rs11212617 variant may be important in assessing the glycaemic response to metformin treatment for insulin resistance in HIV-infected patients., (© 2012 British HIV Association.)
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- 2013
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12. Ubiquitous transgenic overexpression of C-C chemokine ligand 2: a model to assess the combined effect of high energy intake and continuous low-grade inflammation.
- Author
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Rodríguez-Gallego E, Riera-Borrull M, Hernández-Aguilera A, Mariné-Casadó R, Rull A, Beltrán-Debón R, Luciano-Mateo F, Menendez JA, Vazquez-Martin A, Sirvent JJ, Martín-Paredero V, Corbí AL, Sierra-Filardi E, Aragonès G, García-Heredia A, Camps J, Alonso-Villaverde C, and Joven J
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- Adipocytes pathology, Animals, Autophagy, Body Weight, Chemokine CCL2 genetics, Cytokines genetics, Diet, High-Fat, Glucose metabolism, Lipid Metabolism, Macrophages immunology, Mice, Mice, Inbred C57BL, Mice, Transgenic, TOR Serine-Threonine Kinases physiology, Chemokine CCL2 physiology, Energy Intake, Inflammation etiology
- Abstract
Excessive energy management leads to low-grade, chronic inflammation, which is a significant factor predicting noncommunicable diseases. In turn, inflammation, oxidation, and metabolism are associated with the course of these diseases; mitochondrial dysfunction seems to be at the crossroads of mutual relationships. The migration of immune cells during inflammation is governed by the interaction between chemokines and chemokine receptors. Chemokines, especially C-C-chemokine ligand 2 (CCL2), have a variety of additional functions that are involved in the maintenance of normal metabolism. It is our hypothesis that a ubiquitous and continuous secretion of CCL2 may represent an animal model of low-grade chronic inflammation that, in the presence of an energy surplus, could help to ascertain the afore-mentioned relationships and/or to search for specific therapeutic approaches. Here, we present preliminary data on a mouse model created by using targeted gene knock-in technology to integrate an additional copy of the CCl2 gene in the Gt(ROSA)26Sor locus of the mouse genome via homologous recombination in embryonic stem cells. Short-term dietary manipulations were assessed and the findings include metabolic disturbances, premature death, and the manipulation of macrophage plasticity and autophagy. These results raise a number of mechanistic questions for future study.
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- 2013
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13. The deleterious influence of tenofovir-based therapies on the progression of atherosclerosis in HIV-infected patients.
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Aragonès G, Pardo-Reche P, Fernández-Sender L, Rull A, Beltrán-Debón R, Rodríguez-Gallego E, Camps J, Joven J, and Alonso-Villaverde C
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- Adenine adverse effects, Adenine therapeutic use, Atherosclerosis blood, Chemokine CCL2 blood, HIV Infections blood, Interleukin-6 blood, Prospective Studies, Tenofovir, Adenine analogs & derivatives, Atherosclerosis chemically induced, HIV Infections drug therapy, Organophosphonates adverse effects, Organophosphonates therapeutic use, Reverse Transcriptase Inhibitors adverse effects, Reverse Transcriptase Inhibitors therapeutic use
- Abstract
We investigated the potential differential effects of antiretroviral therapies on unbalanced chemokine homeostasis and on the progression of atherosclerosis in HIV-infected patients. A two-year prospective study was performed in 67 consecutive HIV-infected patients initiating antiretroviral therapy with abacavir/lamivudine or tenofovir/emtricitabine. Circulating levels of inflammatory biomarkers, progression of subclinical atherosclerosis and expression levels of selected chemokines genes in circulating leukocytes were assessed. Control subjects showed significantly lower plasma concentrations of CRP, tPA, IL-6, and MCP-1 than HIV-infected patients at a baseline. After two years of followup, the observed decreases in plasma inflammatory biomarker levels were only significant for MCP-1, tPA, and IL-6. The decrease in plasma MCP-1 concentration was associated with the progression of atherosclerosis, and this effect was negligible only in patients receiving TDF-based therapy. Multivariate analysis confirmed that treatment with TDF was positively and significantly associated with a higher likelihood of subclinical atherosclerosis progression. However, the expression levels of selected genes in blood cells only showed associations with the viral load and total and HDL-cholesterol levels. Current antiretroviral treatments may partially attenuate the influence of HIV infection on certain inflammatory pathways, though patients receiving TDF therapy must be carefully monitored with respect to the presence and/or progression of atherosclerosis.
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- 2012
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14. PPARs in Regulation of Paraoxonases: Control of Oxidative Stress and Inflammation Pathways.
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Camps J, García-Heredia A, Rull A, Alonso-Villaverde C, Aragonès G, Beltrán-Debón R, Rodríguez-Gallego E, and Joven J
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The paraoxonase (PON) group of enzymes, composed of PON1, PON2, and PON3, play an important role in decreasing oxidative stress by degrading lipid peroxides. PON1 synthesis is upregulated by PPAR. Several pharmacological compounds (acting as antioxidants and, hence, atheroprotective) stimulate both PPAR activity and PON1 expression. Recent evidence suggests that PON1 and the monocyte chemoattractant protein-1 (MCP-1) are involved in coordinating the inflammatory response in damaged tissues; PPAR may be central in the regulation of these biochemical pathways. This article reviews the state of knowledge on PON1 biochemistry and function, the influence of genetic variation, and the regulation of PON1 expression by pharmaceutical compounds that increase PPAR activity. We also describe recent lines of evidence suggesting links between PON1 and MCP-1 and how their production may be regulated by PPAR.
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- 2012
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15. Pitfalls in measuring high-density lipoprotein cholesterol concentrations in HIV-infected patients.
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Aragonès G, Beltrán R, Rull A, Marsillach J, Rodríguez F, Alí SB, Fernández-Sender L, Camps J, Joven J, and Alonso-Villaverde C
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- Adult, Apolipoprotein A-I blood, C-Reactive Protein analysis, Chemical Precipitation, Data Interpretation, Statistical, False Negative Reactions, Female, Humans, Male, Middle Aged, Polymers, Reagent Kits, Diagnostic, Ultracentrifugation methods, gamma-Globulins analysis, Cholesterol, HDL blood, HIV Infections blood, Specimen Handling methods
- Abstract
Objectives: HIV infection and its treatment are associated with dyslipidaemia and increased risk of cardiovascular disease. Accurate high-density lipoprotein (HDL) cholesterol values are necessary for the management of these abnormalities, but current methods have not been properly assessed in these patients. The aim of this study was to assess in HIV-infected patients the consistency and accuracy of a synthetic polymer/detergent homogeneous assay used to measure HDL cholesterol concentrations and to evaluate the impact of storage., Methods: HDL cholesterol was measured using a synthetic polymer/detergent homogeneous method in samples from HIV-infected patients and healthy subjects for each of the storage regimens: baseline, after 1 week at 4 degrees C, and after 12 months at -80 degrees C. The ultracentrifugation and precipitation assays were used for comparison., Results: Three out of every 20 samples from HIV-infected patients had discrepant HDL cholesterol values with respect to the ultracentrifugation method. Overestimation was associated with high C-reactive protein concentrations and underestimation with plasma gamma-globulin concentrations, an effect that was amplified by any of the storage conditions tested., Conclusions: Caution is needed when using the synthetic polymer/detergent homogeneous method for direct measurement of HDL cholesterol concentrations in HIV-infected patients. This assay is of limited use in clinical trials in which frozen samples are analysed.
- Published
- 2010
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16. Nonconcordance between subclinical atherosclerosis and the calculated Framingham risk score in HIV-infected patients: relationships with serum markers of oxidation and inflammation.
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Parra S, Coll B, Aragonés G, Marsillach J, Beltrán R, Rull A, Joven J, Alonso-Villaverde C, and Camps J
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- Adult, Age Factors, Aryldialkylphosphatase metabolism, Atherosclerosis chemically induced, Atherosclerosis pathology, Biomarkers blood, Body Mass Index, Cardiovascular Diseases blood, Cardiovascular Diseases complications, Carotid Arteries diagnostic imaging, Chemokine CCL2 blood, Epidemiologic Methods, Female, HIV Infections blood, HIV Infections drug therapy, HIV-Associated Lipodystrophy Syndrome complications, HIV-Associated Lipodystrophy Syndrome etiology, Humans, Interleukin-6 blood, Lipoproteins, LDL blood, Male, Oxidative Stress, Tunica Intima pathology, Tunica Media pathology, Ultrasonography, Anti-HIV Agents adverse effects, Atherosclerosis complications, Cardiovascular Diseases etiology, Carotid Arteries pathology, HIV Infections complications
- Abstract
Objectives: HIV-infected patients show an increased cardiovascular disease (CVD) risk resulting, essentially, from metabolic disturbances related to chronic infection and antiretroviral treatments. The aims of this study were: (1) to evaluate the agreement between the CVD risk estimated using the Framingham risk score (FRS) and the observed presence of subclinical atherosclerosis in HIV-infected patients; (2) to investigate the relationships between CVD and plasma biomarkers of oxidation and inflammation., Methods: Atherosclerosis was evaluated in 187 HIV-infected patients by measuring the carotid intima-media thickness (CIMT). CVD risk was estimated using the FRS. We also measured the circulating levels of interleukin-6, monocyte chemoattractant protein-1 (MCP-1) and oxidized low-density lipoprotein (LDL), and paraoxonase-1 activity and concentration., Results: There was a weak, albeit statistically significant, agreement between FRS and CIMT (kappa=0.229, P<0.001). A high proportion of patients with an estimated low risk had subclinical atherosclerosis (n=66; 56.4%). In a multivariate analysis, the presence of subclinical atherosclerosis in this subgroup of patients was associated with age [odds ratio (OR) 1.285; 95% confidence interval (CI) 1.084-1.524; P=0.004], body mass index (OR 0.799; 95% CI 0.642-0.994; P=0.044), MCP-1 (OR 1.027; 95% CI 1.004-1.050; P=0.020) and oxidized LDL (OR 1.026; 95% CI 1.001-1.051; P=0.041)., Conclusion: FRS underestimated the presence of subclinical atherosclerosis in HIV-infected patients. The increased CVD risk was related, in part, to the chronic oxidative stress and inflammatory status associated with this patient population.
- Published
- 2010
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