Uso de Electromiografía de Alta Densidad en las Distrofias Musculares: una Mirada Actual / Use of high-density electromyography in muscular dystrophies: a current look

Introducción. Las distrofias musculares son trastornos genéticamente heredados que causan la degeneración progresiva de las fibras musculares. La electromiografía, especialmente la de alta densidad, se ha convertido en una herramienta valiosa para el diagnóstico y el estudio de la función muscular de trastornos neuromusculares. Objetivo. Describir y discutir el uso actual de esta técnica en las distrofias musculares. Métodos. Se realizó un Scoping Review sobre el uso de electromiografía de alta densidad en personas con distrofia muscular. Se buscó en PubMed, ScienceDirect, Scopus, Web of Science y Biblioteca Cochrane Plus, usando palabras clave en inglés y español. Se consideraron estudios desde 2015 a la fecha. Se identificaron tres artículos que cumplían con los criterios establecidos. Resultados. Los estudios se centraron en aplicaciones clínicas y de bioingeniería para personas con distrofia muscular de Duchenne y distrofia facioescapulohumeral. Los resultados sugieren que variables como la fatiga, la activación temporo-espacial y la dimensionalidad en gestos motores están determinados por la degeneración de las fibras musculares, el reemplazo por tejido fibrótico, los cambios adaptativos y la debilidad muscular progresiva característica de este grupo de condiciones. Se resalta la utilidad de la electromiografía de alta densidad en la evaluación y el manejo de la distrofia muscular. Conclusiones. El uso de esta técnica en estos trastornos neuromusculares sigue en aumento, pero se hace necesario explorar más aristas para ampliar su uso como herramienta en el estudio y en el desarrollo de intervenciones terapéuticas en esta condición por parte de profesionales de la salud.

Background. Muscular dystrophies are genetically inherited disorders that cause progressive degeneration of muscle fibers. Electromyography, especially high-density electromyography, has become a valuable tool for the diagnosis and study of muscle function in neuromuscular disorders, so the objective of this study is to describe and discuss the current use of this technique in muscular dystrophies. Methods. A Scoping Review was carried out on the use of high density electromyography in people with muscular dystrophy. PubMed, ScienceDirect, Scopus, Web of Science, and Cochrane Plus Library were searched using keywords in English and Spanish. Studies from 2015 to date were considered. Three articles were identified that met the established criteria. Results. The studies focused on clinical and bioengineering applications for people with Duchenne muscular dystrophy and facioscapulohumeral dystrophy. The results suggest that variables such as fatigue, temporal-spatial activation and dimensionality in motor gestures are determined by the degeneration of muscle fibers, replacement by fibrotic tissue, adaptive changes and progressive muscle weakness characteristic of this group of conditions. The usefulness of high-density electromyography in the evaluation and management of muscular dystrophy is highlighted. Conclusions. The use of this technique in these neuromuscular disorders continues to increase, but it is necessary to explore more aspects to expand its use as a tool in the management of this condition.

Comportamiento del tabaquismo en estudiantes de primer año de medicina de la Universidad de Ciencias Médicas de Cienfuegos

Fundamento: el hábito de fumar se ha convertido en uno de los mayores problemas de Salud Pública a escala internacional. La Organización Mundial de la Salud reporta al tabaquismo como la principal causa prevenible de enfermedad, discapacidad y muerte prematura. Cuando este consumo se inicia en la adolescencia temprana, favorece la consolidación del hábito de fumar, el cual se extiende hasta la vida adulta. Objetivo: caracterizar el comportamiento del tabaquismo en estudiantes de primer año de medicina de la Universidad de Ciencias Médicas de Cienfuegos. Métodos: se realizó un estudio descriptivo, de corte transversal en estudiantes de primer año de medicina de la Universidad de Ciencias Médicas de Cienfuegos en el período comprendido desde el 5 de septiembre de 2018 al 20 de julio de 2019. El universo estuvo constituido por 199 estudiantes y la muestra quedó conformada por 61 de ellos. Se estudiaron las variables: edad, sexo, color de la piel, inicio del consumo, causas que motivaron al hábito de fumar y lugar de consumo. Fueron empleados como métodos estadísticos, las frecuencias absolutas y los porcentajes. Los resultados se presentaron en cuadros estadísticos. Resultados: el 30,5 % de los adolescentes son fumadores y predominó el sexo femenino con un 85,24 %. Predominó el grupo de 18 años, con un 67,21 %. El 77,04 % comenzó a fumar después de los 16 años y el 100 % fuma en lugares públicos. Conclusiones: se evidenció un incremento del hábito de fumar en adolescentes a expensas del sexo femenino cuyo comienzo del hábito fue en edades tempranas.

Background: smoking has become one of the biggest problems of international Public Health. The World Health Organization reports smoking as the leading preventable cause of disease, disability, and premature death. When said consumption begins in early adolescence, it favors the consolidation of the smoking habit, which extends into adulthood. Objective: to characterize the behavior of smoking in first-year medical students at the University of Medical Sciences of Cienfuegos. Methods: a descriptive, cross-sectional study was carried out in first-year medical students at the University of Medical Sciences of Cienfuegos in the period from September 5, 2018 to July 20, 2019. The universe consisted of 199 students and the sample was made up of 61 of them. The variables: age, sex, skin color, start of consumption, causes that motivated smoking and place of consumption were studied. Absolute frequencies and percentages were used as statistical methods. The results were presented in statistical tables. Results: 30.5 % of adolescents are smokers and 85.24 % are female. The 18-year-old group predominated, with 67.21 %. 77.0 4 % started smoking after the age of 16 and 100 % smoke in public places. Conclusions: there was evidence of an increase in the smoking habit in adolescents at the expense of the female sex, whose habit began at an early age.

Tongue Necrosis due to Giant Cell Arteritis / Necrose da língua por arterite de células gigantes

Giant Cell Arteritis is a vasculitis that mainly affects women over 50. The most common manifestations are headache, jaw claudication, and amaurosis. If not diagnosed early, it can lead to rare irreversible ischemic consequences, with tongue necrosis being one of these. We report a case of a previously undiagnosed patient with lateral tongue necrosis who responded well to oral corticosteroid treatment. The diagnosis is clinical, laboratory and histological and may be aided by imaging exams. Initial treatment is with oral corticosteroids, with methotrexate and tocilizumab as alternatives. Diagnostic suspicion and quick start of treatment favorably influence the prognosis of the disease (AU)

Apresentamos um caso de arterite de células gigantes com amaurose, seguida de necrose da língua, diagnosticado clinicamente com boa resposta terapêutica ao corticoide oral. Salientamos que os casos de necrose da língua são extremamente raros. A suspeita diagnóstica de arterite de células gigantes é de fundamental importância e mesmo na impossibilidade de realizar a biópsia de artéria temporal, não se deve retardar o início do tratamento sob pena de acarretar sequelas definitivas ou manifestações mais graves da doença (AU)

Distrofias Musculares en Adultos y Actividad Física: una Revisión Narrativa / Muscular Dystrophies in Adults and Physical Activity: a Narrative Review

Introducción. Las distrofias musculares son un grupo heterogéneo de trastornos genéticos degenerativos del músculo que comparten características clínicas de debilidad muscular. Recientemente, la actividad física ha vuelto a ser posicionada como una intervención clave en esta población, sin embargo, no existe consenso terapéutico relativo a la prescripción de ejercicio. Junto con describir los principales tipos de distrofias musculares del adulto, el objetivo de esta revisión es describir los efectos clínicos y eventos adversos del ejercicio y la actividad física en las personas adultas con distrofias musculares. Método. Se realizó una revisión narrativa con enfoque cuantitativo en las bases de datos PubMed, Scielo, Scopus y Biblioteca Cochrane Plus utilizando las palabras claves en inglés "muscular dystrophy", "muscular dystrophies", "physical activity", "exercise" y, en español, "distrofia muscular", "distrofias musculares", "actividad física" y "ejercicio" con estudios hasta la fecha. Se seleccionaron siete ensayos controlados aleatorios y un metaanálisis para su revisión. Resultados. En los ocho estudios seleccionados se presentan los outcomes respecto a la fuerza muscular, capacidad aeróbica, capacidades funcionales, dolor, fatiga y efectos adversos. Se presentan resultados que muestran que las intervenciones en modalidad de entrenamiento de fuerza, aeróbica o ambas pueden tener mejoras y/o no tener efecto significativo en sus resultados. Asimismo, ningún estudio mostró efectos negativos y/o deletéreos posteriores a las intervenciones realizadas. Conclusiones. La realización de actividad física en las diversas distrofias musculares prevalentes en el adulto presenta efectos clínicos positivos y/o nulos, sin embargo, se requiere de estudios que aporten una mayor calidad de evidencia.

Introduction. Muscular dystrophies are a heterogeneous group of genetic degenerative muscle disorders that share clinical characteristics of muscle weakness. Recently, physical activity has been positioned as a key intervention in this population. However, there is no therapeutic consensus regarding the exercise prescription. Along with describing the main types of adult muscular dystrophies, this review aims to describe the clinical effects and adverse events of exercise and physical activity in adults with muscular dystrophies. Method. A narrative review with a quantitative approach was carried out in the PubMed, Scielo, Scopus and Cochrane Plus Library databases using the keywords in English "muscular dystrophy", "muscular dystrophies", "physical activity", "exercise" and in Spanish "distrofia muscular", "distrofias musculares", "actividad física" and "ejercicio" with studies to date. Seven randomized controlled trials and one meta-analysis were selected for review. Results. In the eight selected studies, the outcomes regarding muscle strength, aerobic capacity, functional capacities, pain, fatigue, and adverse effects are presented. Results show that interventions in strength training, aerobic training, or both may have improvements and/or not have a significant effect on their results. Likewise, no study showed adverse and/or harmful effects after the interventions were carried out. Conclusions. The performance of physical activity in the various muscular dystrophies prevalent in adults has positive and/or null clinical effects. However, studies that provide a higher quality of evidence are required.

Structural and functional analyses of the Porphyromonas gingivalis type IX secretion system PorN protein.

Porphyromonas gingivalis, the major human pathogen bacterium associated with periodontal diseases, secretes virulence factors through the Bacteroidetes-specific type IX secretion system (T9SS). Effector proteins of the T9SS are recognized by the complex via their conserved C-terminal domains (CTDs). Among the 18 proteins essential for T9SS function in P. gingivalis, PorN is a periplasmic protein that forms large ring-shaped structures in association with the PorK outer membrane lipoprotein. PorN also mediates contacts with the PorM subunit of the PorLM energetic module, and with the effector's CTD. However, no information is available on the PorN structure and on the implication of PorN domains for T9SS assembly and effector recognition. Here we present the crystal structure of PorN at 2.0-Å resolution, which represents a novel fold with no significant similarity to any known structure. In agreement with in silico analyses, we also found that the N- and C-terminal regions of PorN are intrinsically disordered. Our functional studies showed that the N-terminal disordered region is involved in PorN dimerization while the C-terminal disordered region is involved in the interaction with PorK. Finally, we determined that the folded PorN central domain is involved in the interaction with PorM, as well as with the effector's CTD. Altogether, these results lay the foundations for a more comprehensive model of T9SS architecture and effector transport.

Protein Interactome Analysis of the Type IX Secretion System Identifies PorW as the Missing Link between the PorK/N Ring Complex and the Sov Translocon.

The type IX secretion system (T9SS) transports cargo proteins through the outer membrane of Bacteroidetes and attaches them to the cell surface for functions including pathogenesis, gliding motility, and degradation of carbon sources. The T9SS comprises at least 20 different proteins and includes several modules: the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, the outer membrane Sov translocon, and the cell attachment complex. However, the spatial organization of these modules is unknown. We have characterized the protein interactome of the Sov translocon in Porphyromonas gingivalis and identified Sov-PorV-PorA as well as Sov-PorW-PorN-PorK to be novel networks. PorW also interacted with PGN_1783 (PorD), which was required for maximum secretion efficiency. The identification of PorW as the missing link completes a continuous interaction network from the PorL/M motor to the Sov translocon, providing a pathway for cargo delivery and energy transduction from the inner membrane to the secretion pore. IMPORTANCE The T9SS is a newly identified protein secretion system of the Fibrobacteres-Chlorobi-Bacteroidetes superphylum used by pathogens associated with diseases of humans, fish, and poultry for the secretion and cell surface attachment of virulence factors. The T9SS comprises three known modules: (i) the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, (ii) the outer membrane Sov translocon, and (iii) the cell surface attachment complex. The spatial organization and interaction of these modules have been a mystery. Here, we describe the protein interactome of the Sov translocon in the human pathogen Porphyromonas gingivalis and have identified PorW as the missing link which bridges PorN with Sov and so completes a continuous interaction network from the PorL/M motor to the Sov translocon, providing, for the first time, a pathway for cargo delivery and energy transduction from the inner membrane to the secretion pore.

Molecular Strategies Underlying Porphyromonas gingivalis Virulence.

The anaerobic Gram-negative bacterium Porphyromonas gingivalis is considered the keystone of periodontitis diseases, a set of inflammatory conditions that affects the tissues surrounding the teeth. In the recent years, the major virulence factors exploited by P. gingivalis have been identified and characterized, including a cocktail of toxins, mainly proteases called gingipains, which promote gingival tissue invasion. These effectors use the Sec pathway to cross the inner membrane and are then recruited and transported across the outer membrane by the type IX secretion system (T9SS). In P. gingivalis, most secreted effectors are attached to anionic lipopolysaccharides (A-LPS), and hence form a virulence coat at the cell surface. P. gingivalis produces additional virulence factors to evade host immune responses, such as capsular polysaccharide, fimbriae and outer membrane vesicles. In addition to periodontitis, it is proposed that this broad repertoire of virulence factors enable P. gingivalis to be involved in diverse human diseases such as rheumatoid arthritis, and neurodegenerative, Alzheimer, and cardiovascular disorders. Here, we review the major virulence determinants of P. gingivalis and discuss future directions to better understand their mechanisms of action.

La amenaza del cambio climático a la salud de la población y la necesidad urgente de actuar

Climate change is associated with negative health outcomes, such as cardiovascular and respiratory diseases. This article analyses the threat of climate change on population health and the urgent need to implement measures to avoid this damage. Heat vulnerability, heatwave exposures, and wildfire exposure to forest fires have increased in Chile. In 2018, the annual mean concentration of fine particulate matter (PM2.5) exceeded the safe level proposed by the World Health Organization, increasing the risk of negative health outcomes. Thus, multidisciplinary and intersectoral mitigation and adaptation policies are needed. Among other elements, mental health impacts of climate change, health education provided by health workers to reduce negative health impacts of climate change, greater engagement of academia to generate evidence useful for policy-making processes and a better articulation between central and local governments should be considered. Finally, achieving a healthy population should be the aim of all these policies and efforts.

Influencia de los radicales libres en la génesis de la ateroesclerosis / Influence of Free Radicals in the Origin of Atherosclerosis

RESUMEN Muchos de los componentes patológicos de las enfermedades cardiovasculares están estrechamente relacionados con una desregulación del metabolismo de las especies reactivas de oxígeno que propician la aparición del llamado estrés oxidativo. La oxidación de las lipoproteínas de baja densidad, la disfunción endotelial y los procesos inflamatorios están mediados en parte por el aumento en la producción celular de las especies reactivas de oxígeno. Con el objetivo de realizar una actualización sobre los últimos hallazgos que explican la influencia de los radicales libres en la génesis de la aterosclerosis, se realiza la presente revisión bibliográfica en la que se concluyó que el oxígeno constituye la principal fuente de formación de radicales libres, cuya acción es fundamental en el surgimiento de aterosclerosis. El incremento del estrés oxidativo favorece todas las fases del proceso aterotrombótico: adhesión y agregación plaquetaria, proliferación celular, peroxidación lipídica y proteica, daños irreversibles al ADN y a la membrana mitocondrial e inestabilización de la placa.

ABSTRACT Most of the pathologic components of oxidative stress of cardiovascular diseases are closely related with diregulation of metabolism of reactive species of oxygen, which favor the appearance of the so called oxidative stress. The oxidation of low density lipoproteins, endothelial dysfunction and inflammatory processes are mediated in some way by cellular production of the reactive oxygen species. This review is conducted aimed at revising the latest findings that explain the influence of free radicals in the origin of atherosclerosis. It is concluded that oxygen is the main source of free radical formation whose action is determinant for the genesis of atherosclerosis. The increase of oxidative stress favors atherothrombatic phases: platelet adhesion and aggregation, cell proliferation, lipid and protein perioxidation, irreversible damage in DNA and mitochondrial membrane and inestabilzation/desestabilization of the plaque.

[The threat of climate change on population health and the urgent need to act]. / La amenaza del cambio climático a la salud de la población y la necesidad urgente de actuar.

Climate change is associated with negative health outcomes, such as cardiovascular and respiratory diseases. This article analyses the threat of climate change on population health and the urgent need to implement measures to avoid this damage. Heat vulnerability, heatwave exposures, and wildfire exposure to forest fires have increased in Chile. In 2018, the annual mean concentration of fine particulate matter (PM2.5) exceeded the safe level proposed by the World Health Organization, increasing the risk of negative health outcomes. Thus, multidisciplinary and intersectoral mitigation and adaptation policies are needed. Among other elements, mental health impacts of climate change, health education provided by health workers to reduce negative health impacts of climate change, greater engagement of academia to generate evidence useful for policy-making processes and a better articulation between central and local governments should be considered. Finally, achieving a healthy population should be the aim of all these policies and efforts.

Presencia de factores de riesgo para enfermedades crónicas no transmisibles en población supuestamente sana en Cienfuegos / Presence of Risk Factors for Chronic Non-communicable Diseases in a Supposedly Healthy Population in Cienfuegos

RESUMEN Fundamento: la elevada incidencia y prevalencia de las enfermedades crónicas no transmisibles hacen que su atención adquiera carácter inminente en las proyecciones del sistema de salud para fortalecer el manejo y control de los diferentes factores de riesgo que las acompañan. Objetivo: determinar el comportamiento de las principales enfermedades crónicas no transmisibles y factores de riesgo en población supuestamente sana en Cienfuegos. Métodos: se realizó un estudio descriptivo correlacional en el trimestre comprendido entre el 1ro de julio hasta el 30 de septiembre del 2018, en donantes de sangre del Banco Provincial de Cienfuegos. El universo estuvo constituido por 1200 donantes que asistieron a realizar una donación en el periodo de estudio y la muestra fue de 66 donantes que cumplieron con los criterios de inclusión y exclusión. Las variables analizadas fueron: edad, sexo, color de la piel, enfermedades crónicas, tabaquismo y obesidad. Los datos fueron procesados y analizados con métodos estadísticos acordes al estudio realizado (tasa de prevalencia, frecuencia, porcentaje y X2 de Pearson). Resultados: predominaron los hombres como portadores de enfermedades crónicas (21,31 %), los individuos del color de piel blanca (53,03 %). La enfermedad crónica más prevalente fue la hipertensión arterial (21,21 %), y entre los factores de riesgo, la obesidad (43,93 %) y el tabaquismo (33,33 %). Conclusiones: predominaron los hombres en las edades comprendidas entre 25-44 años. Las enfermedades crónicas y factores de riesgo están presentes mayoritariamente en los hombres. Los factores de riesgo estudiados están presentes tanto en los portadores como en los no portadores de padecimientos crónicos.

ABSTRACT Foundation: the high incidence and prevalence of chronic non-communicable diseases make their attention become imminent in the projections of the health system to strengthen the management and control of the different risk factors accompanying them. Objective: to determine the behavior of the main chronic non communicable diseases and risk factors in the supposedly healthy population in Cienfuegos. Methods: a correlational descriptive study was conducted in the trimester from July 1 to September 30, 2018, in blood donors of the Provincial Bank of Cienfuegos. The universe consisted of 1,200 donors who attended a donation in the study period and it shows 66 donors who met the inclusion and exclusion criteria. The variables studied were: age, sex, skin color, chronic diseases, smoking and obesity. The data were processed and analyzed with statistical methods according to the study carried out (prevalence rate, frequency, percentage and Pearson's X2). Results: men predominated as carriers of chronic diseases (21,31 %), individuals of the white race (53,03 %). The most prevalent chronic disease was arterial hypertension (21,21 %). As well as risk factors such as obesity (43,93 %) and smoking (33,33 %). Conclusions: men between 25-44 years old predominated. The chronic diseases studied and risk factors are present mostly in men. The risk factors studied are present in both carriers and non-carriers of chronic diseases.

Breast tumor localization using skin surface temperatures from a 2D anatomic model without knowledge of the thermophysical properties.

Breast cancer is the second most common type of cancer among women after nonmelanoma skin cancer. Use of mammography, the main method to diagnose the disease, has several limitations in parts of the population. The primary goal of this work was to detect and localize the geometric centers of mammary tumors using only superficial temperatures of the breast skin. The 2D anatomic geometry of the breast was simulated using the commercial software COMSOL to obtain the distribution of skin temperature in the three main types of breast cancer. Random errors of  ±â€¯2% were added to the simulated temperatures. The temperature variation caused by each type of cancer on the healthy tissue was correlated with auxiliary temperature profiles. These auxiliary temperature profiles were obtained with no prior knowledge of the thermophysical properties of the tumor apart from the mean values for thermal conductivity and blood perfusion of the layers of healthy breast tissue. The results showed that the maximum error for geometric center estimation was 0.32 cm for invasive lobular carcinoma, with a diameter of 1 cm, positioned 5 cm from the skin surface. Thus, this work contributes to studies aiming to improve the use of infrared thermography for early breast cancer diagnosis, as the results showed that localization of tumors using only superficial temperature profiles does not require prior knowledge of the thermophysical properties of the tissues.

La lipemia en donantes de sangre y su asociación con el riesgo de enfermedades cardiovasculares / Lipidemia in Blood Donors and its Association with Risk of Cardiovascular Diseases

Fundamento: existe una subvaloración de la significación de la lipemia como indicador de problema de salud en individuos que acuden a donar sangre. Objetivo: estimar la prevalencia de factores de riesgo para enfermedades cardiovasculares y medir su asociación con la presencia de lipemia en donantes de sangre. Métodos: se realizó un estudio descriptivo, analítico de casos y controles con 33 y 66 pacientes respectivamente realizado en el Banco Provincial de Sangre de Cienfuegos, desde el 1ro de marzo hasta el 31 de octubre del año 2015. Los casos fueron identificados como positivos en la prueba de lipemia predonación y los controles, con prueba negativa. Se consideraron las variables: donantes aptos y no aptos, lipemia, edad, sexo, hábito de fumar, diabetes mellitus, hipertensión arterial, cintura abdominal, índice de masa corporal, triglicéridos, colesterol total y sus fracciones. Se calculó el coeficiente de correlación de Pearson para medir asociación entre variables con un intervalo de confianza del 95 %, Chi cuadrado X2 y Odds Ratio. Resultados: la lipemia representó el 30,6 % de las causas de rechazo en los donantes de sangre. Los principales factores de riesgo encontrados fueron lipoproteínas de baja densidad disminuida, lipoproteínas de baja densidad aumentada, obesidad, hipertrigliceridemia, hábito de fumar e hipertensión arterial. Las variables con valores más altos de los Odds Ratio fueron lostriglicéridos, lipoproteínas de baja densidad colesterol, cintura abdominal y el índice de masa corporal. Conclusiones: los donantes con plasma turbio tienen un perfil cardiometabólico más favorable para padecer enfermedades cardiovasculares que aquellos con prueba de lipemia negativa.

Foundation: there is an undervaluing of what lipidemia means as a sign of a health problem in individuals who go to donate blood. Objective: to estimate the prevalence of risk factors for cardiovascular diseases and to measure its association with the presence of lipidemia in blood donors. Methods: a descriptive analytic study of cases and controls with 33 and 66 patients respectivelyat the Cienfuegos Provincial Blood Bank, from March 1st to October 31st 2015. Cases were identified as positive at the pre-donating lipidemia test and the controls with negative test. The variables considered were: suitable and not suitable donors, lipidemia, age, smoking habit, diabetes mellitus, high blood pressure, abdominal waist, body mass index, triglycerides, total cholesterol and their fractions. It was calculated the Pearson correlation coefficient to measure the association among variables with a confidence interval of 95%, Squared Chi X2 and Odds Ratio. Results: lipidemia represented 30 % of the refusal causes in blood donors.The main risk factors found were decreased lipoproteins of low density, increased lipoproteins of low density obesity, hypertriglyceridemia, smoking habit and high blood pressure. The variables with higher values in Odd Ratios were triglycerides, abdominal waist, lipoproteins of low cholesterol level, abdominal waist and body mass index. Conclusion:donors with turbid plasma have a more favorable cardiometabolic profile to suffer from cardiovascular diseases than those with negative lipidemia

Spontaneous light-induced Turing patterns in a dye-doped twisted nematic layer.

Optical pattern formation is usually due either to the combination of diffraction and nonlinearity in a Kerr medium or to the temporal modulation of light in a photosensitive chemical reaction. Here, we show a different mechanism by which light spontaneously induces stripe domains between nematic states in a twisted nematic liquid crystal layer doped with azo-dyes. Thanks to the photoisomerization process of the dopants, light in the absorption band of the dopants creates spontaneous patterns without the need of temporal modulation, diffraction, Kerr or other optical nonlinearity, but based on the different scales for dopant transport processes and nematic order parameter, which identifies a genuine Turing mechanism for this instability. Theoretically, the emergence of the stripe patterns is described on the basis of a model for the dopant concentration coupled with the nematic order parameter.

Biochemical and genetic analyses of N metabolism in maize testcross seedlings: 2. Roots.

KEY MESSAGE: Intracellular factors differentially affected enzyme activities of N assimilation in the roots of maize testcrosses where alanine aminotransferase and glutamate synthase were the main enzymes regulating the levels of glutamate. N is a key macronutrient for plant growth and development. Breeding maize with improved efficiency in N use could help reduce environmental contamination as well as increase profitability for the farmers. Quantitative trait loci (QTL) mapping of traits related to N metabolism in the root tissue was undertaken in a maize testcross mapping population grown in hydroponic cultures. N concentration was negatively correlated with root and total dry mass. Neither the enzyme activities nor metabolites were appreciably correlated between the root and leaf tissues. Repeatability measures for most of the enzymes were lower than for dry mass. Weak negative correlations between most of the enzymes and dry mass resulted likely from dilution and suggested the presence of excess of enzyme activities for maximal biomass production. Glutamate synthase and alanine aminotransferase each explained more variation in glutamate concentration than either aspartate aminotransferase or asparagine synthetase whereas glutamine synthetase was inconsequential. Twenty-six QTL were identified across all traits. QTL models explained 7-43% of the variance with no significant epistasis between the QTL. Thirteen candidate genes were identified underlying QTL within 1-LOD confidence intervals. All the candidate genes were located in trans configuration, unlinked or even on different chromosomes, relative to the known genomic positions of the corresponding structural genes. Our results have implications in improving NUE in maize and other crop plants.

Biochemical and genetic analyses of N metabolism in maize testcross seedlings: 1. Leaves.

KEY MESSAGE: Aside from the identification of 32 QTL for N metabolism in the seedling leaves of a maize testcross population, alanine aminotransferase was found to be a central enzyme in N assimilation. Excessive application of nitrogen (N) fertilizer to grow commercial crops like maize is a cause of concern because of the runoff of excess N into streams and rivers. Breeding maize with improved N use efficiency (NUE) would reduce environmental pollution as well as input costs for the farmers. An understanding of the genetics underlying N metabolism is key to breeding for NUE. From a set of 176 testcrosses derived from the maize IBMsyn10 population grown in hydroponics, we analyzed the youngest fully expanded leaf at four-leaf stage for enzymes and metabolites related to N metabolism. Three enzymes, along with one metabolite explained 24% of the variation in shoot dry mass. Alanine aminotransferase (AlaAT) stood out as the key enzyme in maintaining the cellular level of glutamate as it alone explained 58% of the variation in this amino acid. Linkage mapping revealed 32 quantitative trait loci (QTL), all trans to the genomic positions of the structural genes for various enzymes of N assimilation. The QTL models for different traits accounted for 7-31% of the genetic variance, whereas epistasis was generally not significant. Five coding regions underlying 1-LOD QTL confidence intervals were identified for further validation studies. Our results provide evidence for the key role of AlaAT in N assimilation likely through homeostatic control of glutamate levels in the leaf cells. The two QTL identified for this enzyme would help to select desirable recombinants for improved N assimilation.

Resistencia antimicrobiana del Staphylococcus aureus resistente a meticilina en el Hospital Dr. Gustavo Aldereguía Lima / Antimicrobial resistance of methicillin-resistant Staphylococcus aureus at the Dr. Gustavo Aldereguía Lima Hospital

Fundamento: Las bacterias multirresistentes a los medicamentos son un problema creciente en los hospitales de todo el mundo. El Staphylococcus aureus resistente a meticilina es el germen responsable de una parte considerable de infecciones, tanto dentro como fuera de los hospitales. Objetivo: describir la resistencia antimicrobiana del Staphylococcus aureus resistente a meticilina. Métodos: estudio descriptivo, con muestras clínicas de pacientes atendidos en el Hospital Dr. Gustavo Aldereguía Lima, de Cienfuegos, en el año 2014. Para las 142 muestras clínicas analizadas, se estudió el servicio de procedencia, tipo de muestra y resistencia bacteriana. Las muestras fueron analizadas en el Laboratorio de Microbiología del Hospital. Para la detección de resistencia se emplearon discos de cefoxitín, por el método de difusión Kirby Bauer. Resultados: el Staphylococcus aureus resistente a meticilina se aisló con mayor frecuencia en pacientes ingresados en el hospital (55,0 %), causando fundamentalmente infecciones de piel y mucosas (50,6 %). Mostró mayor resistencia a eritromicina y azitromicina, tanto en pacientes hospitalizados como atendidos en consulta externa. Se obtuvieron 15 patrones de corresistencia, de los cuales el patrón azitromicina, eritromicina, ciprofloxacino, fue el más freuente (70 aislamientos). Conclusión: los elevados patrones de corresistencia antimicrobiana reafirmaron el carácter multirresistente de Staphylococcus aureus resistente a meticilina, el cual mostró resistencia a más de dos clases de antibióticos en las muestras analizadas.

Foundation: Multidrug-resistant bacteria are a growing problem in hospitals around the world. Methicillin-resistant Staphylococcus aureus is the germ responsible for a considerable part of infections both inside and outside hospitals. Objective: To describe the antimicrobial resistance of methicillin-resistant Staphylococcus aureus. Methods: A descriptive study with clinical samples of patients attended at Dr. Gustavo Aldereguía Lima Hospital, Cienfuegos, in the year 2014. For the 142 clinical samples analyzed, the service of origin, type of sample and bacterial resistance were studied. Samples were analyzed in the Laboratory of Microbiology of the Hospital. Cefoxitin discs were used for the detection of resistance by the Kirby Bauer diffusion method.Results: Methicillin-resistant Staphylococcus aureus was most frequently isolated in hospitalized patients (55.0%), mainly causing skin and mucosal infections (50.6%). He showed greater resistance to erythromycin and azithromycin, both in hospitalized and outpatient patients. 15 patterns of resistance were obtained, of which the pattern azithromycin, erythromycin, ciprofloxacin, was the most frequent (70 isolates).Conclusion: The high antimicrobial co-resistance patterns confirmed the multidrug resistance character of methicillin of Staphylococcus aureus, which showed resistance to more than two types of antibiotics in the analyzed samples.

Growth hormone and cortisol secretion in the elderly evaluated using the glucagon stimulation test.

OBJECTIVES: The glucagon stimulation test is a reliable alternative test to assess growth hormone and cortisol secretion, but has not been widely used in the elderly population. The aim of this study was to evaluate growth hormone and cortisol secretion using the glucagon stimulation test in an elderly population without known hypothalamic-pituitary disease and to correlate growth hormone and cortisol peaks with age (less than or greater than 80 years) and body mass index. METHODS: Forty-two subjects (67-88 years) from the geriatric ambulatory unit were submitted and 41 subjects completed the glucagon stimulation test. RESULTS: Median growth hormone peak was 5.99 µg/L and median cortisol peak was 21.6 µg/dL. Growth hormone peak was >3 µg/L in 73.2%, and cortisol peak was >18 µg/dL in 65.8% of patients. There was a statistically significant positive correlation between the growth hormone peak and the cortisol peak. The cortisol peak was significantly different between subjects stratified by growth hormone peak of < or >3 µg/L (15.7 and 21.8 µg/dL, respectively). There was a statistically significant difference in cortisol peak according to age < or > 80 years (22.4 and 18.5 µg/dL, respectively). Considering lower cut-offs recently proposed for growth hormone peak (1.0 µg/L for overweight subjects) and cortisol peak (9.1 µg/dL), only two patients had a growth hormone peak below this value, and all patients had preserved cortisol secretion. CONCLUSIONS: We did find a positive correlation between growth hormone and cortisol peaks in the glucagon stimulation test in the elderly, confirming the capacity of the glucagon stimulation test to stimulate both axes. According to the new proposed cut-points for growth hormone and cortisol, we had 95% of normal growth hormone and 100% of normal cortisol responses.