Classical description of the parameter space geometry in the Dicke and Lipkin-Meshkov-Glick models.

We study the classical analog of the quantum metric tensor and its scalar curvature for two well-known quantum physics models. First, we analyze the geometry of the parameter space for the Dicke model with the aid of the classical and quantum metrics and find that, in the thermodynamic limit, they have the same divergent behavior near the quantum phase transition, as opposed to their corresponding scalar curvatures which are not divergent there. On the contrary, under resonance conditions, both scalar curvatures exhibit a divergence at the critical point. Second, we present the classical and quantum metrics for the Lipkin-Meshkov-Glick model in the thermodynamic limit and find a perfect agreement between them. We also show that the scalar curvature is only defined on one of the system's phases and that it approaches a negative constant value. Finally, we carry out a numerical analysis for the system's finite sizes, which clearly shows the precursors of the quantum phase transition in the metric and its scalar curvature and allows their characterization as functions of the parameters and of the system's size.

Dermo-epidermal organotypic cultures for in vitro evaluation of skin irritation and corrosion.

In recent years, in-vitro skin models for chemical hazard identification have been developed. Most of them consist only of human keratinocytes, neglecting the contribution of other skin constituents. Cultures containing the dermal and epidermal component provide an attractive system to investigate, in a more realistic model, toxicological responses, which represents a distinct advantage over keratinocytes-based models that do not mimic faithfully the in vivo environment. This study aimed to validate dermo-epidermal organotypic cultures (ORGs) as a platform to perform irritation and corrosion tests. Skin models were constructed by seeding keratinocytes on fibroblast-containing fibrin gels. After 21 days, the ORGs were evaluated histologically, and the irritant and corrosion potential was determined by means of viability measurements (MTT assay) and cytokine release, according to 431 and 439 OECD tests guidelines. Skin models showed similar histological characteristics to native skin and were able to classify different substances with high accuracy, showing their applicability to skin irritation and corrosion tests. Although cytokines release seems to be chemical-dependent, a tendency was observed, leading to the improvement of the prediction capacity. Nevertheless, further studies should be done to reduce variability in order to increase prediction capacity.

Utility of point-of-care vs reference laboratory testing for the evaluation of glucose levels.

AIMS: To assess the level of agreement between point-of-care and laboratory reference glucose values in defining glycaemic status. METHODS: We analysed 1292 overweight/obese, non-institutionalized participants, aged 40-65 years, in the San Juan Overweight Adults Longitudinal Study. Fasting venous blood glucose was determined using a point-of-care Bayer Contour Blood Glucose Meter and by Vitros System 250 instrument (laboratory). American Diabetes Association thresholds were used to classify participants into normoglycaemia (< 5.6 mmol/l), prediabetes (5.6 to 6.9 mmol/l), or diabetes groups (≥ 7 mmol/l). RESULTS: Bland-Altman plot analysis showed a slope of 0.04 (P=0.002) for the regression between the mean difference and the average of the two methods. The slopes were significantly different from zero among people with normoglycaemia (ß=-0.57, P<0.001), and prediabetes (ß=-0.75, P<0.001) but not among people with diabetes (ß=-0.02, P=0.68). When the prediabetes and diabetes groups were merged into one group, the slope was 0.01, and the glucose values remained similar using the two methods (P=0.76). CONCLUSION: Point-of-care blood glucose measurement may be useful to screen people with diabetes, and to assess glucose among individuals with diabetes where blood can be drawn, but laboratory tests are unavailable or untimely.

Evidence-based guides in tracheostomy use in critical patients

Objetivos: Proporcionar guías de traqueostomía para el paciente crítico, basadas en la evidencia científica disponible, y facilitar la identificación de áreas en las cuales se requieren mayores estudios. Métodos: Un grupo de trabajo formado con representantes de 10 países pertenecientes a la Federación Panamericana e Ibérica de Sociedades de Medicina Crítica y Terapia Intensiva y a la Latin American Critical Care Trial Investigators Network(LACCTIN) desarrollaron estas recomendaciones basadas en el sistema Grading of Recommendations Assessment, Development and Evaluation (GRADE). Resultados: El grupo identificó 23 preguntas relevantes entre las 87 preguntas planteadas inicialmente. En la búsqueda inicial de la literatura se identificaron 333 estudios, de los cuales se escogieron un total de 226. El equipo de trabajo generó un total de 19 recomendaciones: 10 positivas (1B = 3, 2C = 3, 2D = 4) y 9 negativas (1B = 8, 2C = 1). En 6 ocasiones no se pudieron establecer recomendaciones. Conclusión: La traqueostomía percutánea se asocia a menor riesgo de infecciones en comparación con la traqueostomía quirúrgica. La traqueostomía precoz solo parece reducir la duración de la ventilación mecánica pero no la incidencia de neumonía, la duración de la estancia hospitalaria o la mortalidad a largo plazo. La evidencia no apoya el uso de broncoscopia de forma rutinaria ni el uso de máscara laríngea durante el procedimiento. Finalmente, el entrenamiento adecuado previo es tanto o más importante que la técnica utilizada para disminuir las complicaciones.(AU)

OBJECTIVES: Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research. METHODS: A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions. CONCLUSION: Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.(AU)

Hybrid photoluminescent materials containing a benzobisthiazole core for liquid crystal and gel applications.

Tetra- and hexacatenar amide compounds containing a linear centrosymmetric benzobisthiazole core were synthesized with good yields. These compounds were characterized and their structures confirmed by elemental analysis, and FT-IR, Maldi mass and NMR spectroscopy. All compounds exhibited excellent thermal stability up to 330 °C. The tetracatenar series containing a double substitution in the meta positions did not show mesomorphic behaviour, whereas the hexacatenar and tetracatenar series having a double substitution in the meta and para positions showed liquid crystal properties with optical textures typical of columnar mesophases corroborated by POM analysis. The mesomorphic properties were dependent on the length, number and position of alkoxy chains attached at the end of the rigid core. XRD studies of the hexacatenar series showed the hexagonal columnar structure of the mesophases. Photoluminescence properties in solution were observed in the visible region, with good quantum yields. In the solid state, these compounds behave as blue emitters and they are able to change colour with acid or base addition. The hexacatenar benzobisthiazole compound with an alkoxy chain of 14 carbons presented properties of a supergelator in chloroform, leading to the formation of a fluorescent organogel material with fluorescence emission in the blue region.

Evidence-based guides in tracheostomy use in critical patients. / Guías basadas en la evidencia para el uso de traqueostomía en el paciente crítico.

OBJECTIVES: Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research. METHODS: A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions. CONCLUSION: Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.

Demographic and social profile of epilepsy in a vulnerable low-income population in Bogotá, Colombia. / Perfil demográfico y social de la epilepsia en una población vulnerable y de bajos recursos económicos en Bogotá, Colombia.

INTRODUCTION: Very few studies describe the demographic and social profile of epilepsy in vulnerable low-income populations. METHODS: Observational, descriptive, cross-sectional study prospectively recording data from all patients diagnosed with epilepsy who attended a specialist neurology consultation between January and March 2014. Data were analysed using descriptive epidemiology tools. RESULTS: A total of 107 patients were evaluated, of whom 24.2% were illiterate and only 10.2% had completed a higher education programme. Most of the patients (86.8%) had a low socioeconomic status; 73.8% were single and 76.7% were unemployed. The main risk factors for epilepsy in this population were recorded as follows: delayed psychomotor development (n=24, 22.4%), head trauma (n=16, 14.9%), and central nervous system infection (n=13, 12.1%). Most patients (70.1%) responded to antiepileptic drugs (controlled cases) and 15.4% (n=15) had drug-resistant epilepsy (refractory cases). CONCLUSION: The demographic and clinical profiles of the patients included in this study resemble those published for high-income populations; differences are mostly limited to aetiological classification and risk factors. The social profile of the patients evaluated in this study shows high rates of unemployment, illiteracy, and single marital status. These findings seem to be more frequent and prevalent in this group than in high income populations.

A novel TGM1 mutation, leading to multiple splicing rearrangements, is associated with autosomal recessive congenital ichthyosis.

Autosomal recessive congenital ichthyosis (ARCI) is a group of rare, clinically heterogeneous skin disorders that affect cornification. ARCI includes lamellar ichthyosis, congenital ichthyosiform erythroderma and harlequin ichthyosis. TGM1 mutations cause > 50% of ARCI cases in the USA. We report two siblings with ARCI. They were found to carry a novel aetiological TGM1 mutation, which leads to the synthesis of multiple abnormal transcripts. These molecules resulted from three independent mechanisms: intron retention, exon skipping and activation of expand cryptic splice sites. Taken together, our findings expand the known TGM1 mutation repertoire, and provide an insight into the molecular mechanisms leading to ARCI phenotypes. These results could be useful for genetic counselling and future potential genotype-phenotype correlations.

Sperm nuclear decondensation induction capacity of in vitro and in vivo matured canine oocytes.

The objectives of this study were to evaluate the sperm nuclear decondensation capacity of ovulated and in vitro-matured (IVM) canine oocytes during different culture times and correlate this decondensation ability with the state of oocyte nuclear maturation in vitro and in vivo. Fresh ejaculates from three dogs were used for in vitro fertilization (IVF). Dog spermatozoa were cocultured with ovulated or IVM oocytes after each culture period (0, 48, 72 and 96 h) for 24 h. The nuclear stage of the oocytes and the appearance of the sperm nucleus were determined, and data were analysed with a chi-square test. The rates of decondensation and meiotic development in IVM oocytes increased up to 72 h of culture. In contrast, almost all in vivo-matured oocytes showed MII nuclear stage and sperm chromatin decondensation. The percentages of oocytes at MII stage were much lower (p < 0.05) in all IVM groups compared with ovulated oocytes; the rate of sperm chromatin decondensation was higher in ovulated oocytes than in those matured in vitro. Thus, IVM canine oocytes are able to decondense the sperm chromatin during IVF, and this ability increases with time. Nevertheless, sperm chromatin decondensation is less efficient than in ovulated oocytes and may not be completely synchronized with nuclear development as it occurs in vivo.

Late onset ventilator-associated pneumonia due to multidrug-resistant Acinetobacter spp.: experience with tigecycline.

The aim of the study was to evaluate the clinical success rate of 73 patients with ventilator-associated pneumonia (VAP) caused by multidrug-resistant (MDR)-Acinetobacter spp. treated with tigecycline in seven intensive Care Units in Argentina and to determine which predictor variables were significant in this context. Clinical success in our patients was 69.86% (Ci= 58.65-81.07%) 51/73, without significant differences between patients with VAP due to MDR-Acinetobacter spp. carbapenem-susceptible or carbapenem-resistant and only susceptible to colistin, minocyline and tigecycline (70% 44/73 vs. 69% 29/73 respectively, p=0.9006), and between patients who received <48h of prior antibiotics (including those who did not receive any) and those who received >48h of prior antibiotics (73.3% 22/30 vs 67.4% 29/43 respectively, p=0.7791). Age >67 and using other method than BAL for respiratory sampling were identified as predicting variables for negative clinical outcome. Our results suggest that tigecycline may be an acceptable alternative for therapy in patients with VAP caused by MDR-Acinetobacter spp. Nevertheless, only controlled clinical trials will provide the evidence to support approval for new indications.

Revisión clínica: depresión miocárdica en sepsis y shock séptico / Clinical revision: myocardial depression in sepsis and septic shock

La sepsis y el shock séptico son patologías de gran mortalidad, cuyo evento final es la hipotensión refractaria, colapso cardiocirculatorio y falla multiorgánica. En los últimos años se han realizado importantes esfuerzos para entender la disfunción cardiaca asociada a este cuadro, que puede objetivarse hasta en el 50 por ciento de los pacientes con sepsis severa y shock séptico. A pesar de que hoy se acepta que la disfunción miocárdica juega un importante rol en la sepsis, aún no existe consenso respecto a la manera de evaluar la función cardiaca en este contexto, surgiendo nuevas propuestas como el uso de marcadores séricos. Por otra parte, el tratamiento más utilizado hasta hoy han sido los inótropos como la dobutamina, sin embargo con los nuevos estudios sobre la etiología de la disfunción miocárdica, se ha logrado el desarrollo de nuevas líneas experimentales de tratamiento.

The sepsis and the septic shock are pathologies of the great mortality, whose final event is the refractory hypotension, circulatory collapse and multiorganic failure. In the last years important efforts have been made to understand the associate cardiac dysfunction to this picture, which can appear until in 50 percent of the patients with severe sepsis and septic shock. Although today it is accepted that the myocardial dysfunction plays an important role in the sepsis. It does not yet exist consensus with respect to the way to evaluate the function cardiac. New proposals arising as the use from seric markers. On the other hand, the more used treatment until today has been the inotropic agent like the dobutamine. But with the new studies on the etiology of the myocardial dysfunction, has been obtained the development of experimental new line of treatment.

Prevalence and characteristics of smoking in primary healthcare workers in Iquique, Chile.

OBJECTIVE: To determine the prevalence and characteristics of the smoking habits of primary healthcare workers in Iquique, Chile. STUDY DESIGN: Cross-sectional study through a survey of all personnel working in primary health care in Iquique, Chile. METHODS: The following variables were investigated: biodemographical characteristics and aspects of smoking, knowledge of the adverse effects of smoking, and some lifestyle factors. RESULTS: Among the study population, a high prevalence of smokers was found (37%) and a further 26% were ex-smokers. The smokers were predominantly practical nurses, female, aged 25-45 years and married. The only significant relationship was between age and smoking habit (P=0.02), with smoking prevalence among younger groups being very high (56%). There was a high level of awareness about the adverse effects of smoking and its addictiveness (99 and 93%, respectively). Forty-three percent of participants had been smoking for more than 15 years, and the main reasons for smoking were 'social consumption' and 'stress' (36 and 29%, respectively). Thirty-two percent of the ex-smokers ceased smoking for discomfort or health reasons. There were no differences between smokers and ex-smokers with respect to participation in sports or working shifts. Fifty-two percent of those surveyed reported they they were annoyed when others smoked near them. CONCLUSION: This study revealed a high prevalence of smoking, particularly among practical nurses. Regarding attitudes to health, a dichotomy between knowledge and behaviour was found in this group. In pursuing the commitment to smoking cessation in healthcare personnel, a deeper review of cultural issues and motivation should be considered.

Frecuencia de aneurisma aórtico abdominal en población adulta con factores de riesgo conocidos / Frequency of abdominal aortic aneurysms in adult population with known risk factors

BACKGROUND: The incidence of abdominal aortic aneurysms has increased. Its predisposing factors are smoking, high blood pressure and dislipidemia. Progressive aneurysmal enlargement may lead to its rupture, which is associated to a mortality rate above 80 per cent. AIM: To assess the prevalence of abdominal aortic aneurysms in Chilean subjects with cardiovascular risk factors. SUBJECTS AND METHODS: Through announcements in open media we invited individuals aged over 60 years, who smoked, had hypertension and/or had occlusive arterial disease, to participate in a study that included medical history and physical examination. An aortic ultrasound was performed in all subjects in whom the aorta was not palpable or there was a suspicion of dilatation. Aortic diameter over 3 cm was considered aneurysmal. RESULTS: Three hundred fifty six subjects aged 67.1 +/- 6.7 years, (73.9 per cent males), were evaluated. The study group included 62 per cent hypertensives, 39 per cent with abnormal lipids and 46 per cent smokers. Known coronary heart disease or peripheral arterial diseases were present in 14 per cent and 10 per cent, respectively. Ultrasound was required in 159 subjects. Aneurysms were detected in 21 persons (5.9 per cent), 7.6 per cent in males and 1.1 per cent in females. The mean transverse diameter of the aneurysm was 4.1 cm (3-7.5). Aneurysm was found in 2.3 per cent of subjects younger than 65 years and 8.3 per cent of subjects aged over 65 years. CONCLUSIONS: In this sample the prevalence of abdominal aortic aneurysms was 5.9 per cent, affecting predominantly males, with a notorious increase with advanced age.

Tratamiento endovascular del aneurisma de aorta torácica descendente / Endovascular treatment of descending thoracic aorta aneurysm

BACKGROUND: The natural history of aneurysms ends in rupture and death. In 1990 the first endovascular exclusion of an aneurysm, using an endoluminal graft implanted through the femoral arteries was performed. More recently, the same procedure has been used for aneurysms of the thoracic aorta. AIM: To report our experience with endovascular treatment of thoracic aorta aneurysms. MATERIAL AND METHODS: Analysis of 14 patients (nine male), aged 30 to 79 years, treated between May 2001 and August 2002. RESULTS: The mean diameter of the aneurysms was 6.9 cm. The etiology was atherosclerotic in nine patients. The Excluder device (Gore) was preferentially used. There was no operative mortality or paraplegia. One patient had a transient leg monoparesis that reverted completely. No patient had type I endoleaks. Two patients had type II endoleaks on discharge, that sealed spontaneously. In a follow up, ranging from 2 to 17 months, one patient died of a bronchopneumonia and no aneurysm rupture has been detected. CONCLUSIONS: The short term results of endoluminal treatment of thoracic aorta aneurysms are excellent. This treatment is less invasive and has less complications than conventional surgery.

[Endovascular therapy of superior vena cava syndrome: clinical case]. / Terapia endovascular en el sindrome de vena cava superior: caso clínico.

The treatment of superior vena cava syndrome is usually oriented to the underlying cause, that can be too slow in emergency cases. We report a 49 years old woman with a multiple myeloma that was admitted due to a superior vena cava syndrome caused by a central venous catheter used for chemotherapy for 20 weeks. She was successfully treated with thrombolysis, angioplasty and stent placement. The patient died 7 months later due to the underlying disease. Long term catheters are the responsible for 20 to 30% of superior vena cava syndromes. Endovascular treatment of the syndrome is successful in 60 to 100% of cases with a symptomatic relapse in 4 to 45% of patients.

[Ruptured thoracic aorta aneurysm: endovascular treatment]. / Aneurisma roto de aorta torácica descendente: tratamiento endovascular.

In 1991, a technique to exclude aortic aneurysms from circulation inserting an endoluminal graft through the femoral artery, was described. This procedure, usually used for elective abdominal aneurysms, can also be used in the thoracic aorta. We report a 41 years old male with a Marfan syndrome, presenting with a descending aorta aneurysm that ruptured to the mediastinum and pleural cavity. He was compensated hemodynamically and an endovascular stent-graft was deployed at the ruptured zone, through the femoral artery. The postoperative evolution of the patient was uneventful. This technique will allow a less invasive treatment of ruptured aortic aneurysms.

Sodium/calcium exchange in amphibian skeletal muscle fibers and isolated transverse tubules.

The Na(+)/Ca(2+) exchanger participates in Ca(2+) homeostasis in a variety of cells and has a key role in cardiac muscle physiology. We studied in this work the exchanger of amphibian skeletal muscle, using both isolated inside-out transverse tubule vesicles and single muscle fibers. In vesicles, increasing extravesicular (intracellular) Na(+) concentration cooperatively stimulated Ca(2+) efflux (reverse mode), with the Hill number equal to 2.8. In contrast to the stimulation of the cardiac exchanger, increasing extravesicular (cytoplasmic) Ca(2+) concentration ([Ca(2+)]) inhibited this reverse activity with an IC(50) of 91 nM. Exchanger-mediated currents were measured at 15 degrees C in single fibers voltage clamped at -90 mV. Photolysis of a cytoplasmic caged Ca(2+) compound activated an inward current (forward mode) of 23 +/- 10 nA (n = 3), with an average current density of 0.6 muA/muF. External Na(+) withdrawal generated an outward current (reverse mode) with an average current density of 0.36 +/- 0.17 muA/muF (n = 6) but produced a minimal increase in cytosolic [Ca(2+)]. These results suggest that, in skeletal muscle, the main function of the exchanger is to remove Ca(2+) from the cells after stimulation.

Revisión de estudios de meta-análisis en el manejo de la patología infecciosa de oído externo y medio / Meta-analysis study review in the management of infectious pathology of the external and middle ear

El presente artículo pretende mostrar los aspectos más relevantes en el enfoque terapéutico de la patología infecciosa del oído externo y medio. Es por esta razón que se realizó una cuidadosa revisión de los estudios de meta-análisis existentes en la literatura mundial. Como producto de estas revisiones se obtuvo algunos consensos en: otitis externa, otitis media aguda, otitis media con efusión y otitis media crónica supurativa, los cuales fueron revisados y adaptados mostrando en forma clara y concreta el enfoque terapéutico más aceptado por los grandes centros de investigación del mundo. Muchos de los conceptos aquí emitidos son controversias y deben ser analizadas cuidadosamente de acuerdo a las evidencias clínicas e investigativas que se presentan

Técnica quirúrgica utilizada con el implante coclear Combi 40 plus / Surgical technique used with Combi 40 plus cochlear implant

Los avances tecnológicos en el área de los implantes cocleares ha sido grandes. Es por esta razón que el diseño de nuevas estrategias de codificación, cambios en el procesador en cuanto a velocidad y tamaño; así mismo nuevas innovaciones en la conformación del electrodo, entre otros han hecho que sea un área en donde la tecnología se ha colocado al servicio del paciente. Así mismo cada día son más las personas que requieren de los implantes cocleares y es por esta razón que el conocimiento y estandarización de una técnica quirúrgica son vitales, evitando la presentación de complicaciones y optimizando los resultados que se pueden obtener con el implante coclear. El presente estudio muestra la descripción de la técnica quirúrgica utilizada en la colocación del electrodo del implante coclear Combi 40+ y la experiencia obtenida por el Grupo de Implante Coclear del Hospital Militar Central, en los primeros 5 pacientes (2 adultos y 3 niños), utilizando este equipo

Inverted double-gap isolation chamber for high-resolution calcium fluorimetry in skeletal muscle fibers.

Here we describe an improved inverted double-grease-gap isolation chamber that allows the formation of grease seals of high mechanical stability and high electrical resistance. We also provide a detailed description of the procedure used to mount the muscle fibers onto the apparatus. The new chamber permits the electrophysiological study of muscle fibers using an inverted microscope and high-resolution objectives, thus complying with the requirements of modern fluorescence confocal detection methods. The simplicity and reliability of the mounting procedure make this chamber preferable over other gap isolation chambers currently used for simultaneous electrophysiological and optical studies of calcium release. Experimental results obtained from amphibian muscle fibers are presented to illustrate the performance of the chamber when using global fluorescence detection, confocal spot detection, and laser confocal scanning imaging.