RESUMEN
Atrial fibrillation (AF) is the most prevalent arrhythmia and is related with significant morbidity, mortality and costs. In spite of relevant advances in the prevention of embolic events and rhythm control, little has been done to reduce its prevalence, progression and impact, since it increases with ageing as well as with common risk factors such as alcohol intake, tobacco use and stress as well as with arterial hypertension, diabetes mellitus, heart failure, sleep apnea, kidney failure, chronic pulmonary obstructive disease, ischemic heart disease and stroke, among other important comorbidities. Fortunately, new evidence suggests that lifestyle modifications and adequate risk factors and comorbidities control could be effective in primary and secondary AF prevention, especially in its paroxysmal presentations. This is why a multidisciplinary approach integrating lifestyle modifications, risk factors and comorbidities control, is necessary in conjunction with rhythm or rate control and anticoagulation. Unfortunately, that holistic approach strategy is not considered, is scarcely studied or is subtilized in general clinical practice. The present statement's objectives are to: 1) review the relationship between habits, risk factors and illnesses with AF, 2) review the individual and common physiopathology mechanisms of each one of those conditions that may lead to AF, 3) review the effect of control of habits, risk factors and co-morbidities on the control and impact of AF, and 4) supply guidelines and recommendations to start multidisciplinary and integrative AF treatment.
La fibrilación auricular (FA) es la arritmia más frecuente y se asocia con importante morbilidad, mortalidad y costos. A pesar de los grandes avances en la prevención de eventos embólicos y en el control del ritmo, poco se ha realizado para reducir su prevalencia, progresión e impacto, debido a que incrementa con la edad y con la presencia de múltiples factores de riesgo muy comunes en la población, como obesidad, sedentarismo, alcoholismo, tabaquismo y estrés, así como con hipertensión arterial sistémica, diabetes mellitus, insuficiencia cardiaca, apnea del sueño, enfermedad renal crónica, enfermedad pulmonar obstructiva crónica, cardiopatía isquémica y enfermedad vascular cerebral, entre otra comorbilidad importante. Afortunadamente, nuevas evidencias demuestran que las modificaciones en el estilo de vida y el control adecuado de los factores de riesgo y de la comorbilidad pueden ser efectivos en la prevención primaria y secundaria de la FA, en especial en sus formas paroxísticas; para ello, es necesario un manejo multidisciplinario que integre las modificaciones en el estilo de vida, el manejo de los factores de riesgo y el control de la comorbilidad en el tratamiento de la FA en conjunto con el control del ritmo o de la frecuencia y la anticoagulación. Por desgracia, en la práctica clínica estas estrategias a menudo no se tienen en cuenta, son infrautilizadas y poco estudiadas. Los objetivos del presente posicionamiento son: 1) revisar la relación de los factores de riesgo y la comorbilidad con la FA, 2) revisar los mecanismos fisiopatológicos de cada una de estas condiciones, 3) revisar el impacto del control de los factores de riesgo y de la comorbilidad en el control y en el impacto de la FA, y 4) proporcionar guías y recomendaciones para la puesta en práctica de programas de tratamiento multidisciplinario e integral en pacientes con FA.
RESUMEN
Carbon-based nanomaterials have a high thermal conductivity, which can be exploited to prepare nanofluids. Graphene is a hydrophobic substance, and consequently, graphene-based nanofluid stability is improved by adding surfactants. An attractive alternative is the decoration of reduced graphene oxide (rGO) with metallic materials to improve the thermal conductivity without affecting the stability of nanofluids. This study focuses on the synthesis and characterization of rGO/Ag (0.1 wt.%) aqueous nanofluids. Moreover, the effects of the Ag concentration (0.01−1 M) on the thermal conductivity and viscosity during the synthesis of rGO/Ag composite are analyzed. The nanofluid thermal conductivity showed increases in relation to the base fluid, the most promising being 28.43 and 26.25% for 0.1 and 1 M of Ag, respectively. Furthermore, the nanofluids were Newtonian in the analyzed range of shear rates and presented a moderate increase (<11%) in viscosity. Aqueous nanofluids based on rGO/Ag nanocomposites are a potential alternative for applications as heat transfer fluids.
RESUMEN
Current climate change models predict an increased frequency and intensity of drought for much of the developing world within the next 30 years. These events will negatively affect maize yields, potentially leading to economic and social instability in many smallholder farming communities. Knowledge about the genetic resources available for traits related to drought tolerance has great importance in developing breeding program strategies. The aim of this research was to study a maize landrace introgression panel to identify chromosomal regions associated with a drought tolerance index. For that, we performed Genome-Wide Association Study (GWAS) on 1326 landrace progenies developed by the CIMMYT Genetic Resources Program, originating from 20 landraces populations collected in arid regions. Phenotypic data were obtained from early testcross trials conducted in three sites and two contrasting irrigation environments, full irrigation (well-watered) and reduced irrigation (drought). The populations were genotyped using the DArTSeq® platform, and a final set of 5,695 SNPs markers was used. The genotypic values were estimated using spatial adjustment in a two-stage analysis. First, we performed the individual analysis for each site/irrigation treatment combination. The best linear unbiased estimates (BLUEs) were used to calculate the Harmonic Mean of Relative Performance (HMRP) as a drought tolerance index for each testcross. The second stage was a joint analysis, which was performed using the HMRP to obtain the best linear unbiased predictions (BLUPs) of the index for each genotype. Then, GWAS was performed to determine the marker-index associations and the marker-Grain Yield (GY) associations for the two irrigation treatments. We detected two significant markers associated with the drought-tolerance index, four associated with GY in drought condition, and other four associated with GY in irrigated conditions each. Although each of these markers explained less than 0.1% of the phenotypic variation for the index and GY, we found two genes likely related to the plant response to drought stress. For these markers, alleles from landraces provide a slightly higher yield under drought conditions. Our results indicate that the positive diversity delivered by landraces are still present on the backcrosses and this is a potential breeding strategy for improving maize for drought tolerance and for trait introgression bringing new superior allelic diversity from landraces to breeding populations.
RESUMEN
RESUMEN Se presenta el caso de una mujer de 50 arios de edad con cuadro de hemorragia uterina anormal persistente, síndrome anémico secundario, astenia y adinamia, en quien se documenta bicitopenia con anemia normocítica normocrómica y trombocitopenia. Después de realizar un minucioso estudio de las causas de la bicitopenia, se diagnostica síndrome de Sjögren primario, en ausencia de síntomas secos.
ABSTRACT The case is presented of a woman 50 years old with persistent box abnormal uterine bleeding. She has secondary anaemia, adynamia, and asthenia, which is documented as microcytic normochromic anaemia and bicytopenia with thrombocytopenia. After conducting a thorough study of the causes of bicytopenia, the diagnosis of Sjögren's syndrome was made, in the absence of dry symptoms.
Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Síndrome de Sjögren , Enfermedades Hematológicas , Trombocitopenia , Hemorragia Uterina , AnemiaRESUMEN
Maize, the critical staple food for billions of people, was domesticated in Mexico about 9,000 YBP. Today, a great array of maize landraces (MLRs) across rural Mexico is harbored in a living library that has been passed among generations since before the establishment of the modern state. MLRs have been selected over hundreds of generations by ethnic groups for adaptation to diverse environmental settings. The genetic diversity of MLRs in Mexico is an outstanding resource for development of maize cultivars with beneficial traits. Maize is frequently contaminated with aflatoxins by Aspergillus flavus, and resistance to accumulation of these potent carcinogens has been sought for over three decades. However, MLRs from Mexico have not been evaluated as potential sources of resistance. Variation in susceptibility to both A. flavus reproduction and aflatoxin contamination was evaluated on viable maize kernels in laboratory experiments that included 74 MLR accessions collected from 2006 to 2008 in the central west and northwest regions of Mexico. Resistant and susceptible MLR accessions were detected in both regions. The most resistant accessions accumulated over 99 % less aflatoxin B1 than did the commercial hybrid control Pioneer P33B50. Accessions supporting lower aflatoxin accumulation also supported reduced A. flavus sporulation. Sporulation on the MLRs was positively correlated with aflatoxin accumulation (R = 0.5336, P < 0.0001), suggesting that resistance to fungal reproduction is associated with MLR aflatoxin resistance. Results of the current study indicate that MLRs from Mexico are potentially important sources of aflatoxin resistance that may contribute to the breeding of commercially acceptable and safe maize hybrids and/or open pollinated cultivars for human and animal consumption.
