La resistencia a los sulfatos de los cementos portland y su grado de finura de molido: análisis de su relación

This work has demonstrated the great influence that the specific surface of a Portland cement has on its qualification as a high or low resistance to sulfate ion attack - SIA, by means of the accelerated method ASTM C 452. For that purpose two Portland cements have been tested by means of that method. A Portland cement PY (3,83% C3A) (Type V(2)) with 3 different specific surfaces. The experimental results obtained have demonstrated that, according to the ASTM C452-68 method, a Portland Cement Type III(2) can be qualified as from Type V(2), and vice verse, according to its specific surface being adequated, or not, for each objective.Este trabajo ha demostrado la gran influencia que tiene la superficie específica de un cemento portland en su calificación como de alta o baja resistencia al ataque del ion sulfato mediante el método acelerado de ensayo ASTM C 452. Para este objetivo se han ensayado dos cementos portland mediante dicho método de ensayo. Un cemento portland PY (3,83% C3A), Tipo V (2) con 3 diferentes superficies específicas. Los resultados experimentales obtenidos han demostrado que, de acuerdo con el método ASTM C 452, un cemento portland tipo P III (2) puede ser calificado como de Tipo PY Tipo V (2)

Enfermedades neuropediátricas afectan el desarrollo escolar de niños bogotanos

Los niños y jóvenes de los colegios de Bogotá, principalmente en los estratos socioeconómicos más bajos, están registrando una gran prevalencia de problemas del neurodesarrollo y del aprendizaje, lo cual incide negativamente en su desempeño escolar. A esta conclusión llegó el Grupo de Investigación en Neurociencias (Neuros) de la Facultad de Medicina de la Universidad del Rosario, el cual evaluó la prevalencia de las enfermedades neuropediátricas dentro de las que se incluyen los trastornos de aprendizaje, neurodesarrollo y atención, entre otros, en la población infantil de 5 a 12 años de algunos colegios de primaria en las localidades de Barrios Unidos, Bosa, Ciudad Bolívar, Engativá y Usme. Según Alberto Vélez van Meerbeke, miembro del grupo de investigación, aunque la epilepsia y otras enfermedades neurológicas no tienen una prevalencia elevada, la carga de esta enfermedad es importante por cuanto son enfermedades crónicas que pueden por sí solas afectar el desarrollo social, psicológico e intelectual de las personas. En general, afirma Vélez, los niños estudiados no recibían un tratamiento para el problema diagnosticado, debido a que los colegios no están capacitados para atender a los niños con problemas del aprendizaje o no tienen un equipo terapéutico que los apoye. Sólo en colegios privados se encontraron equipos capacitados para esta labor, pero los padres de los niños de estratos más bajos no tienen los recursos para ingresar a dichas instituciones. Incluso, cuando los niños son enviados a la consulta médica, el personal de salud no conoce la problemática y por lo tanto los pacientes se quedan sin la posibilidad de un manejo adecuado. Es decir, que al no ser intervenidos, apoyados y estimulados, continuarán enfrentados a un fracaso continuo con problemas subsiguientes de tipo adaptativo y social. Según Claudia Talero Gutiérrez, investigadora del grupo Neuros, esta cadena lleva a que, en una sociedad que es cada vez más exigente, las expectativas laborales de estos niños al llegar a la vida adulta no vayan más allá de trabajos poco calificados, mal remunerados, inestables y con marginalidad, por lo cual se hace necesario que los niños con dificultades tengan un seguimiento y manejo apropiado de profesionales de la salud, familiares y educadores para garantizar un rendimiento escolar exitoso

Ritmos circadianos de sueño y rendimiento académico en estudiantes de medicina

Objective: to evaluate, with a preliminary study, the distribution of circadian rhythms, sleep schedule patterns and their relationship with academic performance on medical students. Methodology: in this descriptive study, a 10 item original questionnaire about sleep rhythms and academic performance was applied to medical students from different semesters. Week (class time) and weekend schedules, preferences, daytime somnolence and academic performance were asked. Three chronotypes (morningness, intermediate and eveningness) were defined among waking-sleeping preference, difficulty to sleep early, exam preparation preference hour and real sleep schedule. The sleep hour deficit per week night was also calculated. Results: Of the 318 medical students that answered the questionnaire, 62.6% corresponded to intermediate chronotypes, 8.8% to evening-type and 28.7% to morning-type. Significant difference was found among the two chronotype tails (p=0.000, Chi-square 31.13). No correlation was found between academic performance and age, sex, chronotype, week sleep deficit and sleep hours in week and weekends. A 71.1% of the students slept 6 or fewer hours during class time and 78% had a sleep deficit (more frequent in the evening chronotype). Conclusions: No relation was found between sleep chronotype and academic performance. Students tend to morningness. Few studies have been made on equatorial zones or without seasonsObjetivo: hacer un estudio preliminar de la distribución de los ritmos circadianos, los patrones horarios de sueño y su relación con el desempeño académico de estudiantes de medicina. Metodología: estudio descriptivo con aplicación de encuesta original de 10 ítems sobre ritmos de sueño y rendimiento académico a estudiantes de medicina de varios semestres. Se indagó sobre las preferencias y horarios de sueño en fines de semana y entre semana, la somnolencia diurna y el rendimiento académico. Según la preferencia para acostarse y levantarse, la dificultad para dormirse temprano, la preferencia horaria para preparar exámenes y el horario real de sueño, se definieron tres cronotipos (madrugador, intermedio y vespertino). También se calculó el déficit de horas de sueño por noche entre semana. Resultados: de los 318 estudiantes de medicina que respondieron la encuesta, el 62.6 % correspondió al cronotipo intermedio, el 8.8 % al vespertino y el 28.7 % al matutino. La diferencia entre los dos extremos fue estadísticamente significativa, ji-cuadrado 31.13, p=0.000. No se encontró correlación entre el rendimiento académico con edad, sexo, cronotipos, déficit de sueño entre semana y número de horas de sueño entre semana y en fines de semana. El 71.1 % de los estudiantes duerme 6 horas o menos entre semana y un 78 % presenta déficit de sueño que es mayor en los vespertinos. Conclusiones: No se encontró relación entre cronotipo de sueño y rendimiento académico. Los estudiantes tienden a una preferencia matutina. Son pocos los estudios realizados en zonas ecuatoriales o sin estaciones

Clinical and laboratory features of anti-MAG neuropathy without monoclonal gammopathy

Antibodies against myelin-associated glycoprotein (MAG) almost invariably appear in the context of an IgM monoclonal gammopathy associated neuropathy. Very few cases of anti-MAG neuropathy lacking IgM-monoclonal gammopathy have been reported. We investigated the presence of anti-MAG antibodies in 69 patients fulfilling diagnostic criteria for CIDP. Anti-MAG antibodies were tested by ELISA and confirmed by immunohistochemistry. We identified four (5.8%) anti-MAG positive patients without detectable IgM-monoclonal gammopathy. In two of them, IgM-monoclonal gammopathy was detected at 3 and 4-year follow-up coinciding with an increase in anti-MAG antibodies titers. In conclusion, anti-MAG antibody testing should be considered in chronic demyelinating neuropathies, even if IgM-monoclonal gammopathy is not detectable

Chronic administration of Abarema cochliacarpos attenuates colonic inflammation in rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Inflammatory bowel diseases are characterized by a chronic clinical course of relapse and remission associated with self-destructive inflammation of the gastrointestinal tract. Active extracts from plants have emerged as natural potential candidates for its treatment. Abarema cochliacarpos (Gomes) Barneby & Grimes, Fabaceae (Barbatimao), is a native medicinal plant in to Brazil. Previously we have demonstrated in an acute colitis model a marked protective effect of a butanolic extract, so we decided to assess its anti-inflammatory effect in a chronic ulcerative colitis model induced by trinitrobenzensulfonic acid (TNBS). Abarema cochliacarpos (150 mg/day, v.o.) was administered for fourteen consecutive days. This treatment decreased significantly macroscopic damage as compared with TNBS. Histological analysis showed that the extract improved the microscopic structure. Myeloperoxidase activity (MPO) was significantly decreased. Study of cytokines showed that TNF-alpha was diminished and IL-10 level was increased after Abarema cochliacarpos treatment. In order to elucidate inflammatory mechanisms, expression of cyclooxygenase (COX)-2 and nitric oxide synthase (iNOS) were studied showing a significant downregulation. In addition, there was reduction in the JNK and p-38 activation. Finally, I kappa B degradation was blocked by Abarema cochliacarpos treatment being consistent with an up-regulation of the NF-kappaB-binding activity. These results reinforce the anti-inflammatory effects described previously suggesting that Abarema cochliacarpos could provide a source for the search for new anti-inflammatory compounds useful in ulcerative colitis treatment.214680690Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Alagoas, BrazilInstituto Federal de Educacao Ciencia e Tecnologia-Sergipe, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Endpoints and design of clinical trials in patients with decompensated cirrhosis: Position paper of the LiverHope Consortium

Management of decompensated cirrhosis is currently geared towards the treatment of complications once they occur. To date there is no established disease-modifying therapy aimed at halting progression of the disease and preventing the development of complications that can be used for patients with decompensated cirrhosis. The design of clinical trials to investigate new therapies for patients with decompensated cirrhosis is complex. The population of patients with decompensated cirrhosis is heterogeneous (i.e., different etiologies, comorbidities, severity of the disease), leading to the inclusion of diverse populations in clinical trials. In addition, primary endpoints selected for trials that include patients with decompensated cirrhosis are not homogeneous and at times may not be appropriate endpoints. This leads to difficulties in comparing of results obtained from different trials. Against this background, the LiverHope Consortium organized a meeting of experts with the goal of making recommendations for the design of clinical trials and defining appropriate endpoints both for trials aimed at modifying the natural history and preventing progression of decompensated cirrhosis and trials aimed at investigating new therapies for the management of each complication of cirrhosis