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Search Results: 1 - 10 of 300201 matches for " J. Sanchez-Corona "
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Polymorphism Study of the Insulin Receptor Substrate IRS1 and IRS2 Genes Associated with Type 2 Diabetes in Ethnic Groups of Djerba Island
T. Baroudi Ouederni, J. Sanchez-Corona, A. Fadiel, T. Johnson-Scalise, A. Beeghly-Fadiel, S. Flores Martinez, H. Ben Maiz, H. Kammoun Abid, H. Aounallah Skhiri, A. Benammar-Elgaaied and A. Hamza
Clinical Medicine Reviews in Vascular Health , 2012, DOI: 10.4137/CMRVH.S3378
Abstract: Aim: We aimed to evaluate the influence of the Gly972 Arg and Ala513Pro variants of the insulin receptor substrate1 gene (IRS1) and the Gly1057 Asp variant in IRS on type 2 diabetes mellitus (T2DM) in Arab and Berber men and women from Djerba Island, Tunisia. Methods: Genotypes, allelic and genotypic frequencies were studied. The amplified products were analyzed by Restriction Fragment Length Polymorphism (RFLP) methods by comparing T2DM with healthy controls from the same ethnicity. Results: No differences in genotype or allelic frequencies were found between T2DM and healthy controls in either Arab or Berber ethnic groups. Conclusion: The Gly972 Arg and Ala513Pro variants in IRS1 and Gly1057 Asp in IRS2 polymorphisms are not associated with T2DM in the Arab or Berber populations of Djerba Island
PADI4 Haplotypes in Association with RA Mexican Patients, a New Prospect for Antigen Modulation
Maria Guadalupe Zavala-Cerna,Norma Guadalupe Gonzalez-Montoya,Arnulfo Nava,Jorge I. Gamez-Nava,Maria Cristina Moran-Moguel,Roberto Carlos Rosales-Gomez,Susan Andrea Gutierrez-Rubio,Jose Sanchez-Corona,Laura Gonzalez-Lopez,Ingrid Patricia Davalos-Rodriguez,Mario Salazar-Paramo
Journal of Immunology Research , 2013, DOI: 10.1155/2013/383681
Abstract: Peptidyl arginine deiminase IV (PAD 4) is the responsible enzyme for a posttranslational modification called citrullination, originating the antigenic determinant recognized by anti-cyclic citrullinated peptide antibodies (ACPA). Four SNPs (single nucleotide polymorphisms) have been described in PADI4 gene to form a susceptibility haplotype for rheumatoid arthritis (RA); nevertheless, results in association studies appear contradictory in different populations. The aim of the study was to analyze if the presence of three SNPs in PADI4 gene susceptibility haplotype (GTG) is associated with ACPA positivity in patients with RA. This was a cross-sectional study that included 86 RA patients and 98 healthy controls. Polymorphisms PADI4_89, PADI4_90, and PADI4_92 in the PADI4 gene were genotyped. The susceptibility haplotype (GTG) was more frequent in RA patients; interestingly, we found a new haplotype associated with RA with a higher frequency (GTC). There were no associations between polymorphisms and high scores in Spanish HAQ-DI and DAS-28, but we did find an association between RARBIS index and PADI4_89, PADI4_90 polymorphisms. We could not confirm an association between susceptibility haplotype presence and ACPA positivity. Further evidence about proteomic expression of this gene will determine its participation in antigenic generation and autoimmunity. 1. Introduction Rheumatoid arthritis (RA) is an autoimmune disease, characterized by articular inflammation which can lead to joint destruction. RA prevalence is 1% worldwide with considerable variation between ethnic groups, with a higher prevalence in Caucasians compared with Asiatic populations [1, 2]. This disease is more frequent in females (3?:?1) around the fourth decade [3]; some studies suggest that sexual hormones, specifically estrogens, can cause hyperactivity in B and T cell functions [4]. RA represents a disease with risk of function disability due to articular damage as a result of ongoing inflammation, which is irretrievable. In order to limit illness incapability, it is necessary to establish the diagnostic as soon as possible and treat the condition. Genetic predisposition for this disease is supported by the following findings: first degree relatives of patients with RA have a four to six times greater risk to develop the disease [5]; presence of some HLA-DR molecules (HLA-DRB1*0401 and HLA-DRB1*0404) are genetic factors commonly found in RA, and its presence is associated with a more severe disease [6, 7]. The epidemiological genetic information suggests that the heritability for this
Oat Hay Apparent Digestibility, Rumen Ammonia Nitrogen and Bun in Goats Supplemented with Fermented Molasses-Poultry Litter
J. Santos Serrato-Corona,Juan Isidro Sanchez Duarte,Manuel Murillo Ortiz,Edmundo Castellanos Perez
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.808.812
Abstract: The study was conducted to determine oat hay apparent digestibility, blood urea nitrogen and ammonia nitrogen in goats supplemented with fermented molasses-poultry litter. About 20 young Alpine Frances goats with 16.6±1.8 kg initial body weight were used. Goats were randomly assigned to 1 of 4 treatments in a complete randomize design. The evaluated treatments were oat hay (C); oat hay plus 150 g of Molasses-Poultry litter-Soybean Meal mix (MPSM); oat hay plus 150 g of Molasses-Poultry litter-Wheat Meddling mix (MPWM) and oat hay plus 150 g of Molasses-Poultry litter-Sorghum Grain mix (MPSG). Supplements and basal diet (oat hay) were individually fed. Apparent digestibility of DM, OM, NDF, ADF and N were determined. Blood urea nitrogen and ammonia nitrogen were also determined. Feed intake was higher (p = 0.0001) in supplemented goats compared to goats in the control group. Supplemented goats consumed more DM than those in the control group (p = 0.0003). Dry matter retention was not affected by supplementation (p = 0.11). Organic dry matter tended to increase (p = 0.08) in supplemented goats. Supplemented goats retained more nitrogen (p = 0.0001) than those in the control group with values of 6.37, 10.43, 8.59 and 8.00 g day-1 for treatments C, MPSM, MPWM and MPSG, respectively. The concentration of N-NH3 in rumen fluid tended to increase (p = 0.08) as the quantity of nitrogen in the supplement increase. The results shows that supplementation with molasses-poultry litter plus soybean meal, wheat middlings or sorghum grain can increase feed intake and nitrogen retention in growing goats fed oat hay.
CMV Latent Infection Improves CD8+ T Response to SEB Due to Expansion of Polyfunctional CD57+ Cells in Young Individuals
Alejandra Pera, Carmen Campos, Alonso Corona, Beatriz Sanchez-Correa, Raquel Tarazona, Anis Larbi, Rafael Solana
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088538
Abstract: Cytomegalovirus (CMV) latent infection has a deleterious effect on the efficacy of influenza vaccination in the elderly, suggesting that CMV restricts immunological diversity impairing the immune system functionality in old age. Polyfunctional T cells produce multiple cytokines and higher amounts than mono-functional T cells. High number of polyfunctional T cells correlates with better prognosis during infection. Thus, the efficiency of T cell response associates with quality (polyfunctionality) rather than with quantity (percentage of T cells). We analyze the effect of CMV infection on CD8+ T cells polyfunctionality ―degranulation (CD107a), IFN-gamma and TNF-alpha production―, from young CMV-seropositive and CMV-seronegative individuals and in middle age CMV-seropositive donors, in response to Staphylococcal Enterotoxin B (SEB). Our results show a higher percentage of polyfunctional CD8+ T cells in young CMV-seropositive individuals compared to CMV-seronegative. Also, we find an expansion of CD8+CD57+ T cells in CMV-seropositive individuals, which are more polyfunctional than CD8+CD57? cells. In middle age individuals there is a higher frequency of SEB-responding CD8+ T cells, mainly TNF-alpha or TNF-alpha/IFN-gamma producers, whereas the percentage of polyfunctional cells (IFN-gamma/TNF-alpha/CD107a) is similar to the percentages found in young CMV-seropositive. Therefore, whereas it has been shown that CMV latent infection can be detrimental for immune response in old individuals, our results indicate that CMV-seropositivity is associated to higher levels of polyfunctional CD8+ T cells in young and middle age donors. This increase in polyfunctionality, which can provide an immunological advantage in the response to other pathogens, is due to a CD8+CD57+ T cell expansion in CMV-seropositive individuals and it is independent of age. Conversely, age could contribute to the inflammation found in old individuals by increasing the percentage of cells producing pro-inflammatory cytokines. These findings highlight the necessity of further studies on the benefits/detrimental effects of CMV infection in the response to vaccination and other infections.
A Topology for the Penumbral Magnetic Fields
J. Sanchez Almeida
Physics , 2009, DOI: 10.1007/978-3-642-02859-5_16
Abstract: We describe a scenario for the topology of the magnetic field in penumbrae that accounts for recent observations showing upflows, downflows, and reverse magnetic polarities. According to our conjecture, short narrow magnetic loops fill the penumbral photosphere. Flows along these arched field lines are responsible for both the Evershed effect and the convective transport. This scenario seems to be qualitatively consistent with most existing observations, including the dark cores in penumbral filaments reported by Scharmer et al. Each bright filament with dark core would be a system of two paired convective rolls with the dark core tracing the common lane where the plasma sinks down. The magnetic loops would have a hot footpoint in one of the bright filament and a cold footpoint in the dark core. The scenario fits in most of our theoretical prejudices (siphon flows along field lines, presence of overturning convection, drag of field lines by downdrafts, etc). If the conjecture turns out to be correct, the mild upward and downward velocities observed in penumbrae must increase upon improving the resolution. This and other observational tests to support or disprove the scenario are put forward.
Thermal relaxation of very small solar magnetic structures in intergranules: a process that produces kG magnetic field strengths
J. Sanchez Almeida
Physics , 2001, DOI: 10.1086/321532
Abstract: The equilibrium configuration of very small magnetic fluxtubes in an intergranular environment automatically produces kG magnetic field strengths. We argue that such process takes place in the Sun and complements the convective collapse (CC), which is traditionally invoked to explain the formation of kG magnetic concentrations in the solar photosphere. In particular, it can concentrate the very weak magnetic fluxes revealed by the new IR spectro-polarimeters, for which the operation of the CC may have difficulty. As part of the argument, we show the existence of solar magnetic features of very weak fluxes yet concentrated magnetic fields (some 3 x 10^{16} Mx and 1500 G).
Structure and Dynamics of Surface Adsorbed Clusters
J. R. Sanchez
Physics , 1999,
Abstract: Extensive numerical simulation are reported for the structure and dynamics of large clusters on metal(100) surfaces. Different types of perimeter hopping processes makes center-of-mass of the cluster to follow a a random walk trajectory. Then, a {\it diffusion coefficient} $D$ can be defined as $\lim\limits_{t\to \infty} D(t)$, with $D(t)=< d^2 >/(4t)$ and $d$ the displacement of the center-of-mass. In the simulations, the dependence of the diffusion coefficient on those perimeter hopping processes can be analyzed in detail, since the relations between different rates for the processes are explicitly considered as parameters.
Millennium-long summer temperature variations in the European Alps as reconstructed from tree rings
C. Corona,J. Guiot,J. L. Edouard,F. Chalié
Climate of the Past Discussions , 2008,
Abstract: This paper presents a reconstruction of the summer temperatures over the Greater Alpine Region (44.05°–47.41° N, 6.43°–13° E) during the last millennium based on a network of 36 multi-centennial larch and stone pine chronologies. Tree ring series are standardized using an Adaptative Regional Growth Curve, which attempts to remove the age effect from the low frequency variations in the series. The proxies are calibrated using the June to August mean temperatures from the HISTALP high-elevation temperature time series spanning the 1818–2003. The method combines an analogue technique, which is able to extend the too short tree-ring series, an artificial neural network technique for an optimal non-linear calibration including a bootstrap technique for calculating error assessment on the reconstruction. About 50% of the temperature variance is reconstructed. Low-elevation instrumental data back to 1760 compared to their instrumental target data reveal divergence between (warmer) early instrumental measurements and (colder) proxy estimates. The proxy record indicates cool conditions, from the mid-11th century to the mid-12th century, related to the Oort solar minimum followed by a short Medieval Warm Period (1200–1420). The Little Ice Age (1420–1830) appears particularly cold between 1420 and 1820 with summers are 0.8°C cooler than the 1901–2000 period. The new record suggests that the persistency of the late 20th century warming trend is unprecedented. It also reveals significant similarities with other alpine reconstructions.
Extreme Evolutionary Disparities Seen in Positive Selection across Seven Complex Diseases
Erik Corona,Joel T. Dudley,Atul J. Butte
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012236
Abstract: Positive selection is known to occur when the environment that an organism inhabits is suddenly altered, as is the case across recent human history. Genome-wide association studies (GWASs) have successfully illuminated disease-associated variation. However, whether human evolution is heading towards or away from disease susceptibility in general remains an open question. The genetic-basis of common complex disease may partially be caused by positive selection events, which simultaneously increased fitness and susceptibility to disease. We analyze seven diseases studied by the Wellcome Trust Case Control Consortium to compare evidence for selection at every locus associated with disease. We take a large set of the most strongly associated SNPs in each GWA study in order to capture more hidden associations at the cost of introducing false positives into our analysis. We then search for signs of positive selection in this inclusive set of SNPs. There are striking differences between the seven studied diseases. We find alleles increasing susceptibility to Type 1 Diabetes (T1D), Rheumatoid Arthritis (RA), and Crohn's Disease (CD) underwent recent positive selection. There is more selection in alleles increasing, rather than decreasing, susceptibility to T1D. In the 80 SNPs most associated with T1D (p-value <7.01×10?5) showing strong signs of positive selection, 58 alleles associated with disease susceptibility show signs of positive selection, while only 22 associated with disease protection show signs of positive selection. Alleles increasing susceptibility to RA are under selection as well. In contrast, selection in SNPs associated with CD favors protective alleles. These results inform the current understanding of disease etiology, shed light on potential benefits associated with the genetic-basis of disease, and aid in the efforts to identify causal genetic factors underlying complex disease.
Influence of Tempering and Steaming Requirements of Flaked Corn for Feedlot Cattle Diets
R.A. Zinn,J. Salinas,M. Montano,L. Corona
Journal of Animal and Veterinary Advances , 2012,
Abstract: Five trials were conducted to evaluate the influence of tempering and time, delivery rate and pressure of steam on the feeding value of Steam-Flaked Corn (SFC) for feedlot cattle. Trial 1, 4 Holstein steer with cannulas in the rumen and proximal duodenum were used in a 4 4 Latin square design. Treatments were: Dry Rolled Corn, no steam (DRC); Tempered Rolled Corn, no steam (TRC), tempered flaked corn, 5 min steaming time (T-5 min-SFC) and flaked corn, 25 min steaming time (25 min-SFC). There were no treatments effects (p>0.10) on ruminal digestion of OM, DIP and ruminal microbial efficiency. There was a tendency (p = 0.19) for ruminal NDF digestion to be lower for 25 min-SFC than for T-5 min-SFC. Ruminal starch digestion was greater (14.1%, p<0.05) for steam-flaked corn treatments than for rolled corn treatments. Ruminal N efficiency tended to be greater (p = 0.13) for steam flaked corn treatments then for rolled corn treatments. Post ruminal and total tract digestion of OM, starch and N were greater (p<0.05) for steam-flaked corn treatments than for rolled corn treatments (36.8 and 19.3%, respectively). Ruminal pH was lower (4.8%, p<0.05) for steam-flaked corn treatments than for rolled corn treatments. Ruminal acetate: propionate molar ratios and estimated methane production were also lower for steam-flaked corn treatments than for rolled corn treatments. In trial 2, eighty crossbred heifers (248 kg BW) were used in a 105 day randomized complete block design experiment to evaluate treatment effects: No tempering and 117 kPa of steam pressure (NT117); no tempering and 379 kPa of steam (NT379); Tempering and 117 kPa of steam (T117) and Tempering and 379 kPa of steam pressure (T379). There were no treatment effects (p>0.10) on ADG, DMI, gain efficiency, or dietary NE. In trial 3, 4 Holstein steer with ruminal and duodenal cannulas were used in a 4 4 Latin square to evaluate characteristics of digestion of dietary treatment fed in trial 2. Tempering did not affect (p>0. 10) ruminal digestion of OM, starch, or N. However, it increased (p<0.05) post ruminal and total tract digestion of OM (3.4 and 1.4%, respectively) and N (0.6 and 3%, respectively). Increasing steam pressure from 117-379 kPa increased (p<0.05) post ruminal (3.8%) and total tract starch digestion (0.8%). Ruminal and total tract starch digestion averaged 82 and 98%, respectively. In trial 4, 96 crossbred steer calves (347 kg BW) were used in a 56 day trial to evaluate treatment effects on performance and dietary NE value. Treatments were: no tempering and 419 kPa along a 6.35 diam steam line, measured 90 cm proximal to steam chest splitter valves. (NT419); no tempering and 335 kPa of steam (NT335); tempering and 419 kPa of steam (T419) and tempering and 335 kPa of steam pressure (T335). There were no treatment effects (p>0.20) on ADG (1.24 kg day-1), DM conversion (5.60 kg DM kg-1 ADG) and dietary NE for maintenance and gain (2.24 and 1.55 Mcal kg-1, respectively). In trial 5, 4 Holst
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