Subduction zone fluids and arc magmas conducted by lithospheric deformed regions beneath the central Andes.

Dehydration of the oceanic subducting slab promotes the formation of magmatic arcs, intra-slab intermediate-depth seismicity, and hydration of the overlying mantle wedge. However, the complex permeability structure of the overriding plate controls the magma and fluid migration and their accumulation at shallower depths. In this regard, mapping the inner structure of the overriding crust and mantle is crucial to understand the magmatic and hydrological processes in subduction zones. We integrate 3-D P-wave, [Formula: see text], and electrical resistivity tomographic models of the northern Chilean subduction zone to map the magmatic and fluids derived from the subducting oceanic Nazca plate. Results show a continental crust relatively thick (50-65 km) characterized by a lower zone of high [Formula: see text] values (7.2-7.6 km/s), which is interpreted as the presence of plutonic rocks. The mantle lithospheric wedge is weakly hydrated ([Formula: see text] = 1.75-1.8) while the forearc continental crust is traversed by regions of reduced electrical resistivity values ([Formula: see text] [Formula: see text]) interpreted as zones of relatively high permeability/fracturing and fluid content. These regions spatially correlate with upper plate trans-lithospheric deformation zones. Ascending melts accumulate preferentially in the back-arc, whereas hydrothermal systems form trenchward of the volcanic arc. The results highlight the complex permeability structure of the upper South American plate.

Prevalence, geographic distribution and phenotypic differences of Piscirickettsia salmonis EM-90-like isolates.

Early reports accounted for two main genotypes of Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis, placing the single isolate EM-90 apart from the prototypic LF-89 and related isolates. In this study, we provide evidence that, contrary to what has been supposed, the EM-90-like isolates are highly prevalent and disseminated across Chilean marine farms. Molecular analysis of 507 P. salmonis field isolates derived from main rearing areas, diverse hosts and collected over 6 years, revealed that nearly 50% of the entire collection were indeed typed as EM-90-like. Interestingly, these isolates showed a marked host preference, being recovered exclusively from Atlantic salmon (Salmo salar) samples. Although both strains produce undistinguishable pathological outcomes, differences regarding growth kinetics and susceptibility to the antibiotics and bactericidal action of serum could be identified. In sum, our results allow to conclude that the EM-90-like isolates represent an epidemiologically relevant group in the current situation of piscirickettsiosis. Based on the consistency between genotype and phenotype exhibited by this strain, we point out the need for genotypic studies that may be as important for the Chilean salmon industry as the continuous surveillance of antimicrobial susceptibility patterns.

Fixed-points in random Boolean networks: The impact of parallelism in the Barabási-Albert scale-free topology case.

Fixed points are fundamental states in any dynamical system. In the case of gene regulatory networks (GRNs) they correspond to stable genes profiles associated to the various cell types. We use Kauffman's approach to model GRNs with random Boolean networks (RBNs). In this paper we explore how the topology affects the distribution of the number of fixed points in randomly generated networks. We also study the size of the basins of attraction of these fixed points if we assume the α-asynchronous dynamics (where every node is updated independently with probability 0≤α≤1). It is well-known that asynchrony avoids the cyclic attractors into which parallel dynamics tends to fall. We observe the remarkable property that, in all our simulations, if for a given RBN with Barabási-Albert topology and α-asynchronous dynamics an initial configuration reaches a fixed point, then every configuration also reaches a fixed point. By contrast, in the parallel regime, the percentage of initial configurations reaching a fixed point (for the same networks) is dramatically smaller. We contrast the results of the simulations on Barabási-Albert networks with the classical Erdös-Rényi model of random networks. Everything indicates that Barabási-Albert networks are extremely robust. Finally, we study the mean and maximum time/work needed to reach a fixed point when starting from randomly chosen initial configurations.

Absceso del psoas como presentación de tuberculosis vertebral: reporte de un caso / Psoas abscess as spinal tuberculosis presentation: case report

Introducción: El absceso del psoas es un cuadro infrecuente cuyo principal agente etiológico es el Staphyloccocus aureus, y que con baja frecuencia puede ser de etiología tuberculosa como complicación de una afección vertebral por Mycobacterium tuberculosis. Presentación del caso: Mujer de 58 años, mapuche, con antecedentes de enfermedad pulmonar obstructiva crónica y alcoholismo crónico, consultó por cuadro de dos meses de evolución de dolor lumbar, baja de peso y paresia de extremidad inferior derecha que impedía la marcha. Tomografía computada (TC) de columna evidenció espondilodiscitis y absceso del psoas derecho, iniciándose tratamiento antibiótico cubriendo Staphyloccocus aureus. Los hemocultivos y los cultivos de la colección resultaron negativos por lo que se decidió mantener tratamiento ambulatorio. Paciente consultó cuatro meses después por exacerbación de su disnea basal de dos semanas de evolución, radiografía de tórax y TC de tórax de alta resolución compatibles con tuberculosis pulmonar con diseminación miliar bilateral, por lo cual, se inició tratamiento antituberculoso, realizándose baciloscopías que resultaron negativas. Además, se solicitó identificación del bacilo de Koch mediante reacción de polimerasa en cadena que resultó positiva, con lo que se confirmó el diagnóstico de tuberculosis miliar y mal de Pott. Se decidió reevaluar con TC de columna una vez finalizado el tratamiento antituberculoso para decidir conducta quirúrgica. Discusión: Es importante la sospecha activa de etiología tuberculosa ante una espondilodiscitis y un absceso del psoas, pese a su baja frecuencia. El inicio del tratamiento en forma precoz puede modificar la progresión de una infección que puede ser invalidante e incluso mortal.

Introduction: The Psoas abscess is an infrecuent condition which main ethiology is the Staphyloccocus aureus and with less frequency can be a vertebral tuberculosis complication caused by Mycobacterium tuberculosis. Case Report: a 58 years old female, Mapuche, with Chronic Obstructive Pulmonar Disease and chronic alcoholism antecedents, was admitted in the emergency room with a two month old lumbar pain, loss of weight and right inferior extremity paresia which didn't allowed her to walk. The column's Computed Tomography (CT) showed spondylodiscitis and a right psoas abscess, the antibiotherapy, covering Staphyloccocus aureus, was started. The hemoculives and abscess' cultives were negative, so it was decided to continue with ambulatory treatment. The patient was admitted four month later because of two weeks of exacerbation of her basal dysnea. The thorax Radiography and high resolution CT were compatibles with pulmonary tuberculosis with bilateral miliar disemination. Antituberculosis treatment was started, bacilloscopies were negative, also, a Polymerase Chain Reaction identification of Koch's bacillus was performed, resulting positive, confirming the diagnosis of miliar tuberculosis and Pott's disease. Once antituberculosis treatment was finished, a new column's CT was requested to decided surgical conduct. Discussion: Is important to actively suspect of tuberculosis ethiology in presence of spondylodiscitis and psoas abscess, despite it's low frequency. The early treatment start may modify the progresion of an infección that can be invalidating and even mortal.

Evaluación clínico-radiológica y clasificación de la bronquiolitis del adulto / Bronchiolar disorders: clinical-radiological assessment and classification

Bronchiolar disorders are generally difficult to diagnose. A detailed clinical history may point toward a specific diagnosis. Pertinent clinical questions include history of smoking, collagen vascular disease, inhalation injury, medication use and organ transplantation. It is important also to evaluate possible systemic and pulmonary signs of infection, evidence of air trapping, and high-pitched expiratory wheezing, which may suggest small airways involvement. Pulmonary function tests and plain chest radiography may demonstrate abnormalities; however, they rarely prove sufficiently specific to obviate bronchoscopic or surgical biopsy. High-resolution CT (HRCT) scanning of the chest is often an important diagnostic tool to guide diagnosis in these difficult cases, because different subtypes of bronchiolar disorders may present with characteristic image findings. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Primary bronchiolar disorders include acute bronchiolitis, respiratory bronchiolitis, follicular bronchiolitis, mineral dust airway disease, constrictive bronchiolitis, diffuse panbronchiolitis, and other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, collagen vascular disease, respiratory bronchiolitis-associated interstitial lung disease, cryptogenic organizing pneumonia, and pulmonary Langerhans’ cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical and prognostic significance of a bronchiolar lesion is best determined by identifying the etiology, underlying histopathologic pattern and assessing the correlative clinic-physiologic-radiologic context.

Histiocitosis de células de Langerhans pulmonar: Caso clínico / Adult pulmonary Langerhans cell histiocytosis: Report of one case

Adult pulmonary Langerhans cell histiocytosis (PLCH) is a rare disorder of unknown etiology that occurs predominantly in young smokers, with an incidence peak at 20-40 years of age. In adults, pulmonary involvement with Langerhans cell histiocytosis usually occurs as a single-organ disease and is characterized by focal Langerhans cell granulomas infiltrating and destroying distal bronchioles. We report a 23-year-old asymptomatic male smoker with a non specific interstitial infiltrate found in preventive chest X ray examination. A high resolution chest CT scan showed multiple cystic structures predominating in the upper lobes, with small centrilobular nodules. A transbronchial biopsy showed a lymphocytic lung infiltrate with Langerhans cells. A surgical biopsy confirmed the diagnosis of pulmonary Langerhans cell histiocytosis. After six months of follow up, the patient is in good conditions.

[Bronchiolar disorders: clinical-radiological assessment and classification]. / Evaluación clínico-radiológica y clasificación de la bronquiolitis del adulto.

Bronchiolar disorders are generally difficult to diagnose. A detailed clinical history may point toward a specific diagnosis. Pertinent clinical questions include history of smoking, collagen vascular disease, inhalation injury, medication use and organ transplantation. It is important also to evaluate possible systemic and pulmonary signs of infection, evidence of air trapping, and high-pitched expiratory wheezing, which may suggest small airways involvement. Pulmonary function tests and plain chest radiography may demonstrate abnormalities; however, they rarely prove sufficiently specific to obviate bronchoscopic or surgical biopsy. High-resolution CT (HRCT) scanning of the chest is often an important diagnostic tool to guide diagnosis in these difficult cases, because different subtypes of bronchiolar disorders may present with characteristic image findings. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Primary bronchiolar disorders include acute bronchiolitis, respiratory bronchiolitis, follicular bronchiolitis, mineral dust airway disease, constrictive bronchiolitis, diffuse panbronchiolitis, and other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, collagen vascular disease, respiratory bronchiolitis-associated interstitial lung disease, cryptogenic organizing pneumonia, and pulmonary Langerhans' cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical and prognostic significance of a bronchiolar lesion is best determined by identifying the etiology, underlying histopathologic pattern and assessing the correlative clinic-physiologic-radiologic context.

Prueba de caminata en seis minutos en sujetos chilenos sanos de 20 a 80 años / Reference values for the 6-minutes walking test in healthy subjects 20-80 years old

Background: The six minute walking distance test (6MWD) is widely used to evaluate exercise capacity in several diseases due to its simplicity and low cost. Aim: To establish reference values for 6MWD in healthy Chilean individuals. Material and methods: We studied 175 healthy volunteers aged 20-80 years (98 women) with normal spirometry and without history of respiratory, cardiovascular or other diseases that could impair walking capacity. The test was performed twice with an interval of 30 min. Heart rate, arterial oxygen saturation (with a pulse oxymeter) and dyspnea were measured before and after the test. Results: Walking distance was 576 ± 87 m in women and 644 ± 84 m in men (p < 0.0001). For each sex, a model including age, height and weight produced 6MWD prediction equations with a coefficient of determination (R²) of 0.63 for women and 0.55 for men. Conclusions: Our results provide reference equations for 6MWD that are valid for healthy subjects between 20 and 80 years old.

Infección por Bordetella pertussis: una causa emergente de tos prolongada en adolescentes y adultos / Bordetella pertussis infection: an emerging cause of prolonged cough illness in adolescents and adults

Whooping cough is increasingly recognized as a cause of prolonged cough illness in adolescents and adults. Systematic vaccination has changed its epidemiology, with the majority of cases now primarily affecting adolescents and adults. A 45-year-old female, active smoker, nurse, who works in a dialysis service, presented with a 6-week history of bothersome cough and malaise. Thorax x-ray was normal and direct immunofuorescence of nasopharyngeal swab was positive for Bordetella pertussis. This case illustrates pertussis infection in adulthood. We review the main causes of chronic cough in adults: asthma, chronic rhinosinusitis and gastroesophageal refux; the clinical features, prevalence, diagnostic tools, and management of adult patients with B. pertussis infection to increase awareness of this highly contagious disease.

La tos convulsiva o coqueluche está siendo reconocida cada vez con mayor frecuencia como causa de tos prolongada en adolescentes y adultos. La vacunación sistemática de la población pediátrica ha determinado un cambio en el perfl epidemiológico de la enfermedad, aumentando su prevalencia en la población adulta. Se presenta el caso clínico de una paciente de 45 años, fumadora, enfermera de unidad de hemodiálisis, que consulta por malestar general y tos seca de seis semanas de evolución. La radiografía de tórax era normal y la inmunofuorescencia directa de hisopado nasofaríngeo fue positiva para Bordetella pertussis. A propósito de este caso clínico, revisamos las principales causas de tos crónica: asma bronquial, enfermedad rinosinusal y refujo gastroesofágico; el cuadro clínico, evaluación diagnóstica y tratamiento de la infección por B. pertussis en población adulta.

[Reference values for the 6-minutes walking test in healthy subjects 20-80 years old]. / Prueba de caminata en seis minutos en sujetos chilenos sanos de 20 a 80 años.

BACKGROUND: the six minute walking distance test (6MWD) is widely used to evaluate exercise capacity in several diseases due to its simplicity and low cost. AIM: to establish reference values for 6MWD in healthy Chilean individuals. MATERIAL AND METHODS: we studied 175 healthy volunteers aged 20-80 years (98 women) with normal spirometry and without history of respiratory, cardiovascular or other diseases that could impair walking capacity. The test was performed twice with an interval of 30 min. Heart rate, arterial oxygen saturation (with a pulse oxymeter) and dyspnea were measured before and after the test. RESULTS: walking distance was 576 ± 87 m in women and 644 ± 84 m in men (p < 0.0001). For each sex, a model including age, height and weight produced 6MWD prediction equations with a coefficient of determination (R²) of 0.63 for women and 0.55 for men. CONCLUSIONS: our results provide reference equations for 6MWD that are valid for healthy subjects between 20 and 80 years old.