Histopathological survey of parasites harboured by the clam Tawera elliptica (Lamarck, 1818) from Chiloé Archipelago, southeastern Pacific.

Tawera elliptica (commonly known as "Almeja Juliana", is a venerid clam that inhabits sandy bottoms and is distributed from Valparaíso on the Pacific coast up to the Mar del Plata area along the Atlantic coast. Harvests of this clam have declined substantially over the last decade. Therefore, an analysis of common parasites and pathological conditions of this clam was undertaken along with histopathology. Monthly samples were prepared for routine histology for examination under light and electron microscopy. T. elliptica has a sex ratio of 1:1 and the relationship between the shell length and the wet tissue weight is not significantly different between females and males. The maximum values for de condition index and meat yield were found during the austral winter. The following parasites (and their overall prevalence) were detected: intracellular microcolonies of bacteria in digestive gland (22.9%), intestinal epithelium (9.3%) and gills (3.17%), an unidentified cyst in gills (59,3%), a Steinhausia-like intraoocytic microsporidian (5.2%), Gregarine spores (41.3%), ciliated protozoa (16.7%), two metazoa, a Paravortex like flatworm (4.3%), and a digenean trematode (8%). The monthly mean intensity of the most relevant parasites was between 2.3 and 35.6 for digestive gland intracellular microcolonies of bacteria (IMC), 0-5.1 for intestinal epithelium IMC, 0-2 for branchial IMC and 0 - 48 for intraoocytic microsporidium. The prevalence and the infection intensity were low-to very low, and no World Organisation for Animal Health OIE listed parasite was detected. It is concluded that this is a healthy clam, and no disease risks for the cultivation are visualized at present. However, IMC at high prevalence and intensities of infection could be potentially impactful, and the intraoocytic microsporidian could jeopardize reproduction if present in high intensities of infection.

Effect of Sperm Ratio and Temperature on Fertilization and Early Larval Development of the Surf Clam Mesodesma donacium (Bivalvia:Mesodesmatidae).

The effect of sperm ratio on fertilization was evaluated in five sperm:oocytes treatments (10:1, 50:1, 100:1, 500:1 and 1000:1), the effect of temperature on embryonic and larval development in three temperature treatments (13 °C, 16 °C and 19 °C) was recorded and the duration of each stage, the growth rate and survival rate were registered. The oocytes were spherical (67.5 ± 4.2 µm) with a defined nucleus. Spermatozoa had a circular head (2 µm) and a fusiform flagellum (12 µm). The 500:1 sperm:oocytes treatment presented the lowest % of unfertilized oocytes, and lysis was observed in the 1000:1 treatment. An inverse relationship was observed between temperature and the duration of the stages of embryonic development. At 16 °C, veliger D larvae were observed at 41 h 45' pf (88 ± 13.0 µm). Umbonate larvae were obtained at day 16 in the 13 °C culture and at day 10 in the 16 °C and 19 °C treatment (140 µm). On day 16 of culture, advanced umbonate larvae with a well-defined stomach (235 µm) were observed. The larval growth rate was higher in the 19 °C treatment (3.6 µm day-1) than the 13 °C and 16 °C treatment (2, 2.2 µm day-1). The mortality was higher in the 19 °C treatment (91%). These results are an initial contribution towards the culture of M. donacium as part of small-scale aquaculture in South America.

Ambulatory arterial stiffness index in diabetic patients.

Background The ambulatory arterial stiffness index (AASI), derived from 24 h ambulatory blood pressure monitoring (ABPM) can be a good indicator of arterial stiffness. Aim To assess the correlation between AASI and brachial-ankle pulse wave velocity (baPWV), ankle-brachial index (ABI) and cardio-ankle vascular index (CAVI) in patients with type 2 diabetes mellitus without hypertension. Material and Methods Cross sectional study in 28 diabetic patients aged 49 ± 7 years (40% women). AASI was calculated as 1 minus the regression slope of diastolic on systolic blood pressure, using ABPM data. ABPM was measured in the arm using an oscillometric device. ABI was calculated as the ratio between ankle and brachial systolic blood pressure. CAVI was derived from pulse wave velocity using the Vasera VS-1000 device. Correlations were calculated using a bivariate Spearman correlation. Results The mean values for AASI, ABI, baPWV and CAVI were 0.39 ± 0.14, 1.14 ± 0.09, 15.15 ± 2.71 m/s and 7.60 ± 1.90, respectively. There was a significant negative correlation between AASI and ABI (r = -0.491, p < 0.01). Conclusions In these diabetic patients, there was an association between AASI, an arterial stiffness marker and ABI, an indicator for the presence of atherosclerosis.

Evaluación de la metodología Team Based Learning en cursos de estadística para estudiantes de medicina / Evaluation of team-based learning methodology for teaching statistics to medical students

Background Team-Based Learning methodology (TBL) is used in medicine teaching in different clinical and basic fields, but seldom in statistics courses. Aim To compare the performance of students taught using TBL with those receiving the traditional lecture modality. Materials and Methods The grades and percentage of correct answers obtained in exams written during the statistics course of students that were taught without TBL (years 2009-2011) or using this methodology (years 2013-2016) were compared. Z Test for one mean (Milestone 1) and Student's t test for two independent means assuming equal variances/unequal variances (Milestone 2) were evaluated. The mean and minimum grades and the percentage of grades below the flunking threshold were also evaluated. Students' assessment of the methodology was also recorded. Results The percentage of correct answers was 94.2% and 94% among students taught with and without TBL methodology, respectively (Milestone 1), achieving a similar performance independent of the teaching strategy. The global percentage of correct answers of Milestone 2 increased from 75.3% to 89.5% (P < 0.001) among students using TBL. In 75.0% of questions, the percentage of correct answers increased with TBL. Likewise, there was an increase in mean grades increased from 5.4 to 6.2 (P < 0.05) and mean minimum grades from 2.8 to 3.7 (P = 0.05). The proportion of grades below the flunking threshold decreased from 9.9% to 4.4% (P = 0.054). Almost all students evaluated TBL methodology positively. Conclusions Students taught using TBL methodology performed better in the statistics course evaluation than students attending standard lectures in statistical analysis of greater complexity. TBL was well evaluated.

Ejercicio como tratamiento anti-inflamatorio / Exercise as anti -inflammatory treatment

Durante las últimas dos décadas, avances en investigación han revelado el potencial del ejercicio como terapia para enfermedades inflamatorias. Uno de los avances más importantes fue el descubrimiento de sistema de comunicación muscular con otros órganos y tejidos mediante la secreción de proteínas conocidas como mioquinas.Algunas de estas mioquinas, por diferentes mecanismos, inducen respuestas anti-inflamatorias con cada sesión de ejercicio, además de mejorías a largo plazo en factores de riesgo cardiovascular, obteniendo un efecto antiinflamatorio indirecto. Por lo tanto, contrario a la creencia que la actividad física podría agravar los mecanismos inflamatorios, hoy en día se considera al ejercicio como potencial tratamiento para enfermedades inflamatorias.

During the past two decades, advances in research have revealed the role of exercise as a therapy for inflammatory diseases. One of the most important of these advances is the discovery that skeletal muscle communicates with other organs and tissues by secreting proteins called myokines. Some myokines, by different mechanisns, induce anti-inflammatory responses with each bout of exercise and mediate long-term exercise-induced improvements in cardiovascular risk factors, having an indirect anti-inflammatory effect. Therefore, contrary to fears that physical activity might aggravate inflammatory pathways, exercise is now believed to be a potential treatment for patients with inflammatory diseases.

Cefalea en racimos / Cluster headache

La Cefalea en Racimos es una de las cefaleas primarias más dolorosas, con una prevalencia de alrededor de 1-4/1000 adultos de la población general. Aproximadamente el 90% de los individuos afectados experimenta ataques diarios por varias semanas o meses (periodos de racimos o dolor) separados por intervalos libres de dolor que se prolongan por meses o años (periodos de remisión). El restante 10% de los pacientes sufre un patrón más crónico marcado por ataques que persisten por más de 1 año sin periodos de remisión o con periodos de remisión muy cortos. Durante los ataques la mayoría de los pacientes experimenta dolor severo, unilateral,principalmente alrededor de la órbita. El inicio del ataque es rápido y alcanza su pico de intensidad en unos 5 a 15 minutos. La duración usual de los ataques es de 45 minutos hasta 90 minutos, sin embargo pueden prolongarse hasta por 3 o más horas. Se asocian síntomas autonómicos en el mismo lado afectado por el dolor e incluyen inyección conjuntival, epifora, congestión nasal o rinorrea, y Síndrome de Horner de manera parcial. A pesar de que el mecanismo fisiopatológico no se ha dilucidado por completo, su periodicidad circadiana y circanual sugieren la implicación del hipotálamo en la patogénesis de esta afección. La mayoría de los pacientes son manejados de manera exitosa con la terapia médica, la cual puede ser dividida en tratamiento abortivo (como oxígeno o sumatriptan subcutáneo) para ser utilizado durante los ataques y tratamiento profiláctico, el cual busca inducir y mantener los periodos de remisión.

Cluster headache is one of the most painful primary headache disorders with a prevalence of about 1-4/1000 of the adult population. Approximately 90% of affected individuals experience daily attacks for several weeks to months (cluster periods) separated by attack-free intervals lasting for months to years (remission periods). The other 10% of sufferers exhibit a more chronic pattern marked by attacks that persist for longer than 1 year with no remission or only short periods of remission. During attacks, most patients experience severe, unilateral pain, primarily around the orbit. The onset of attack is rapid and reaches peak intensity within 5 to 15 minutes. Attacks typically last from 45 minutes to 90minutes, but they may last longer than 3 or more hours. Associated autonomic symptoms occur on the same side of the headache and include conjunctival injection and lacrimation, nasal congestion or rhinorrhea, and partial Horner syndrome. Despite the pathophysiologic mechanisms remain undetermined, its circadian and circannual periodicity suggest the implication of the hypothalamus in the pathogenesis of the disorder. Most patients are successfully managed with medical therapy; medication management can be divided into abortive treatments (such as oxygen or subcutaneous sumatriptan) for an ongoing attack and prophylactic treatment, which aims to induce and maintain a remission.

Full motor recovery despite striatal neuron loss and formation of irreversible amyloid-like inclusions in a conditional mouse model of Huntington's disease.

The primary mechanism responsible for Huntington's disease remains unknown. Postulated early pathogenic events include the following: impaired protein folding, altered protein degradation, mitochondrial dysfunction, and transcriptional dysregulation. Although related therapies can delay disease progression in mouse models, they target downstream and probably indirect effects of mutant-huntingtin expression. Accordingly, in case they prove beneficial in humans, they might only palliate some aspects of disease. Our previous studies in the Tet/HD94 conditional model and the recently reported efficacy of RNA interference against mutant huntingtin in another mouse model support silencing mutant-huntingtin expression as a valid therapeutic approach that has the advantage of targeting toxicity at its root. Here, we address whether gene silencing can still be beneficial in the late stages of disease with detectable striatal neuron loss. Stereological analysis was applied to determine an age at which Tet/HD94 mice show a decrease in the number of striatal neurons. Then, progression of neuropathology and motor phenotype were analyzed in mice that were allowed to continue expressing mutant huntingtin and in mice that no longer expressed it. Neuronal loss did not revert in gene-off mice, but the additional loss that takes place in gene-on mice was prevented. The total number of huntingtin-containing inclusions dramatically reverted, but a small fraction of inclusions positive for the amyloid dye thioflavin-S remained. Interestingly, despite a 20% decrease in striatal neurons and the presence of amyloid-like irreversible inclusions, gene-off mice fully recover from their motor deficit, thus ruling out amyloid-like huntingtin inclusions as the main toxic species and suggesting that gene-silencing therapies might work in late stages of disease.

Edema pulmonar de las alturas. Consideraciones fisiopatológicas : a propósito de un caso / High altitude pulmonary edema. Physiopathological considerations regarding one case

Uno de los problemas médicos de la altitud lo constituye el Edema Pulmonar de las Alturas (EPA). Generalmente este se presenta en personas que ascienden sin aclimatación a más de 2500 mt de altura sobre el nivel del mar ó en los residentes de altitudes mayores a 3000 mt que descienden por periodos cortos de tiempo a nivel del mar y regresan a su lugar de residencia. A pesar de que se han informado decenas de casos se desconoce su etiopatogenia si bien se han implicado en la genesis factores tanto hidrostráticos como de permeabilidad vascular. En este trabajo presentamos el primer caso de EPA descrito en la literatura nacional y se revisan los factores implicados en su fisiopatología.

Tratamiento de sinositis crónica en adultos con la asociación trimetoprim-sulfametoripirazina / Treatment of chronic sinusitis in adults with the trimetoprim-sulfamethoxyoyrazine combination

Se estudiaron 36 pacientes adultos con diagnóstico de sinusitis crônica a los que se administró la combinación trimetoprim (250 mg) y sulfametoxipirazina (200 mg), dos cápsulas en una toma el primer dia, y una cápsula diaria dos semanas. Los signos y síntomas clínicos que se evaluaron fue obstrucción y secreción nasal, tos, dolor espontáneo y a la presión de los senos paranasales y fiebre. La eficacia clínica de la combinación antimicrobiana fue mayor de 80%, y al bacteriológica de 100%