Conceptos generales en bioestadística y epidemiología clínica: estudios observacionales con diseño de cohorte / General concepts in biostatistics and clinical epidemiology: observational studies with cohort design

Los estudios con diseño de cohorte evalúan la relación entre una exposición y la ocurrencia o no de un evento de interés, comenzando el análisis desde la exposición. Habiendo sido diseños muy utilizados en algunas áreas de la medicina, como la descripción de factores de riesgo cardiovascular o los efectos de la radiación ionizante en humanos, representan una herramienta con características atractivas debido a su adaptabilidad a numerosos contextos, sobre todo en el estudio de exposiciones de baja ocurrencia. Esta revisión es la cuarta entrega de una serie metodológica sobre conceptos generales en bioestadística y epidemiología clínica desarrollada por la Cátedra de Metodología de la Investigación Científica de la Escuela de Medicina de la Universidad de Valparaíso, Chile. En este artículo, se abordan conceptos teóricos generales sobre los estudios de cohorte, considerando aspectos históricos, generalidades sobre la construcción de un estudio utilizando este diseño, presentando distintas variantes y diseños derivados de interés, y potenciales sesgos a los que se puede ver enfrentado el investigador.

Cohort studies evaluate the relationship between exposure to a specific event or phenomenon and the occurrence of an associated out-come of interest (or lack thereof). This methodological design has been widely used in certain areas of medicine, such as the study of cardiovascular risk factors and the effects of ionizing radiation in humans. It is a useful study design, especially for research involving low-occurrence exposures, because it can be easily adapted to various contexts. This article, which provides an overview of observational cohort studies, is part of a methodology series on general concepts in biostatistics and clinical epidemiology developed by the Chair of Scientific Research Methodology at the University of Valparaíso's School of Medicine in Chile. It describes historical, practical, and theoretical concepts related to cohort studies; essential elements in cohort study design, and variations and derivations of it; potential types and sources of bias in these types of observational/longitudinal studies, and various methods researchers can use to address/minimize them.

Pautas Éticas del Consejo de Organizaciones Internacionales de las Ciencias Médicas: avances y temáticas no resueltas en la actualización 2016 / Council for International Organizations of Medical Sciences (CIOMS) Ethical Guidelines: advancements and unsolved topics in 2016 upgrade

A fines del año 2016 se publicó la nueva edición de las Pautas Éticas Internacionales para la Investigación Relacionada con la Salud con Seres Humanos del Consejo de Organizaciones Internacionales de las Ciencias Médicas (CIOMS, por sus siglas en inglés Council for International Organizations of Medical Sciences), estándares universalmente reconocidos en la investigación biomédica. En este artículo se realiza un análisis crítico de las potencialidades y falencias de las nuevas pautas del CIOMS 2016. Algunos avances alcanzados consideran la importancia asignada al valor social de la investigación y su repercusión en la toma de decisiones y la creación de políticas públicas, el desarrollo de investigación en escenarios de bajos recursos, la participación de las comunidades en el proceso investigativo, la determinación de la vulnerabilidad de los participantes de una investigación y los cambios en los procedimientos de consentimiento informado. Esta actualización es una gran herramienta para investigadores y miembros de los comités de ética científica. Asimismo, aunque constituye una adaptación a los rápidos cambios científicos, tecnológicos y sociales; permanecen aspectos no resueltos, principalmente en torno al manejo del riesgo mínimo de los participantes y de los conflictos de interés involucrados en una investigación, además del desarrollo de ésta en escenarios de bajos recursos. No obstante, se hace un positivo progreso en cuanto al contexto y las necesidades de las poblaciones en las que se desarrollarán las investigaciones y la participación comunitaria en las distintas fases del proyecto, accediendo a sus potenciales beneficios. El impacto de las pautas del CIOMS 2016, deberá evaluarse en el tiempo, en particular en escenarios de inequidades socio-sanitarias y de intereses comerciales de la industria en la investigación biomédica.

In 2016, the new edition of the Council for International Organizations of Medical Sciences (CIOMS) Ethical Guidelines was released, which are universally acknowledged as ethical standards in biomedical research. In this article, we critically analyze the improvements and shortcomings of the CIOMS Ethical Guidelines 2016. Among the improvements are the relevance assigned to the social value of research and its effects on decision-making and the creation of public policies; the research development in low-resources scenarios; the communities' involvement in the research process; the determination of participants' vulnerability and changes on informed consent related proceedings. Despite the improved harmonization with scientific, technologic and social changes, and that the guidelines provide a tool for researchers and members of research ethics committees alike, some topics remain unsolved, namely the management of participants' minimal risk and conflicts of interest involved in research, and the development of research in low-incomes scenarios. Nonetheless, we recognize that these new guidelines constitute a progress regarding the context and needs of populations in which research will be conducted, with greater community involvement in the different phases of the investigation project, thus allowing them to access the potential benefits. The impact of the CIOMS Ethical Guidelines 2016, should be appraised over time, particularly in socio-sanitary inequities scenarios and in the context of commercial interests of industry on biomedical research.

Pérdida celular endotelial corneal asociada a facoemulsificación y experiencia del oftalmólogo: análisis prospectivo de datos secundarios individuales / Corneal endothelial cell loss associated to phacoemulsification and ophthalmologist experience: prospective analysis of individual secondary data

Resumen Introducción La facoéresis es el procedimiento en que se extrae quirúrgicamente el cristalino para tratar las cataratas. La pérdida endotelial corneal es una complicación reconocida. Si bien se han descrito diversos factores asociados a este daño, la experiencia del cirujano ha sido poco explorada. Objetivos Evaluar la asociación entre la experiencia del cirujano y otras variables asociadas a la pérdida celular endotelial en el contexto de la facoéresis. Métodos Se analizaron registros clínicos de 198 cirugías de cataratas, evaluando el efecto de la experiencia del cirujano y otras variables asociadas: energía disipada acumulada, tipo de viscoelástico empleado, uso de azul tripán, cantidad de fluídica, tiempo de ultrasonido, energía de facoemulsificación combinada y recuento celular endotelial pre y postoperatorio. Resultados No se observaron diferencias en el conteo postoperatorio de células endoteliales. Los oftalmólogos con más de cinco años de experiencia presentaron menor uso de azul tripán pero mayor cantidad de energía disipada acumulada en cada procedimiento, mientras que los oftalmólogos con menor experiencia utilizaron mayor cantidad de fluídica. Conclusiones Aunque hubo diferencias en el manejo de algunos factores influyentes sobre la pérdida endotelial cornal según la experiencia de los oftalmólogos, no se hallaron diferencias en relación a dicha pérdida como resultado final.

Abstract Introduction Phacoeresis is the procedure through which the lens is surgically removed to treat cataracts. A corneal endothelial loss is a recognized sequel. Although several factors associated with this harm have been described, the surgeon's prior experience has been scarcely evaluated. Objectives To assess the association between the surgeon's experience and other variables associated with a corneal endothelial cell loss in the context of phacoeresis. Methods Clinical records of 198 patients undergoing cataract operations were prospectively reviewed. The experience of the surgeon and other variables were recorded, including cumulative dissipated energy, viscoelastic type, the use of trypan blue, amount of fluidics, ultrasound time, combined phacoemulsification energy, and pre- and postoperative corneal endothelial cell counts. Results No differences were observed in the postoperative corneal endothelial cell count between surgeons with more or less than five years of experience. Nevertheless, ophthalmologists with more than five years' experience used less trypan blue, but more cumulative dissipated energy in each procedure, while less experienced ophthalmologists used less fluidics. Conclusions Although there were differences in the surgical management regarding the surgeons' experience in factors known to influence corneal endothelial cell loss, no differences in endothelial cell loss were observed as an outcome.

Síntesis de información biomédica: revisiones narrativas, revisiones sistemáticas y estructuras emergentes / Syntheses of biomedical information: narrative reviews, systematic reviews and emerging formats

La divulgación de información biomédica se expande de manera exponencial, lo que representa un desafío para aquellos profesionales de la salud que deseen obtener información integrada de alta calidad y relevancia. Las revisiones, en sus distintos formatos, son herramientas que pueden abordar este problema. Este artículo describe los principales tipos de síntesis de información biomédica, sus estructuras, la utilidad de cada una de ellas, y presenta los últimos formatos desarrollados por las diferentes organizaciones que se dedican a la síntesis de información.

Biomedical information dissemination has expanded exponentially, and this can represent a challenge for those health professionals who wish to obtain high quality and relevant integrated information. Reviews, in their different formats, are tools that can address this problem. This article describes the main types of syntheses of biomedical information, their structures, their usefulness, and presents the latest information synthesis formats that were developed by different organizations committed to this purpose.

A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor.

Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 104 cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex show identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.

Saturation mapping of regions determining resistance to Ascochyta blight and broomrape in faba bean using transcriptome-based SNP genotyping.

KEY MESSAGE: Transcriptome-based SNP markers were genotyped in a faba bean map to saturate regions bearing QTL for Ascochyta fabae and broomrape and distinguish positional and functional candidates underlying both resistances. Faba bean is an important food crop worldwide. Marker-assisted selection for disease resistance is a top priority in current faba bean research programs, with pathogens such as Ascochyta fabae and broomrape (Orobanche crenata) being among the major constraints in global faba bean production. However, progress in genetics and genomics in this species has lagged behind that of other grain legumes. Although genetic maps are available, most markers are not in or are too distant from target genes to enable an accurate prediction of the desired phenotypes. In this study, a set of SNP markers located in gene coding regions was selected using transcriptomic data. Ninety-two new SNP markers were genotyped to obtain the most complete map reported so far in the 29H × Vf136 faba bean population. Most of the QTL regions previously described in this cross were enriched with SNP markers. Two QTLs for O. crenata resistance (Oc7 and Oc8) were confirmed. Oc7 and Oc10 located nearby a QTL for A. fabae resistance suggested that these genomic regions might encode common resistance mechanisms and could be targets for selection strategies against both pathogens. We also confirmed three regions in chromosomes II (Af2), III (Af3) and VI associated with Ascochyta blight resistance. The QTLs ratified in the present study are now flanked by or include reliable SNP markers in their intervals. This new information provides a valuable starting point in the search for relevant positional and functional candidates underlying both types of resistance.

A case report of recurrent adult-onset xanthogranuloma: is the radiotherapy a treatment option?

Adult-onset xanthogranuloma (AOX) is one of the four uncommon syndromes called adult xanthogranulomatous disease (AXD), which is diagnosed by characteristic histopathology. AXD is rare and heterogeneous group of entities that can affect multiple organ systems. Orbital involvement is included in the xanthogranulomatous disease although less prevalent. This work focuses on the use of external beam radiotherapy in the control of local symptoms of periocular manifestation of AOX as case report and literature review.

A Twenty-Three-Year-Old Man with a Chronic Anterior Chest Wall Wound, Eosinophilia, and Elevated IgE-Job's Syndrome.

A 23-year-old man presented with a chronic anterior chest wall wound. Previously he had a split thickness skin graft in the area in where the wound bed had become infected, developing a thick purulent drainage. The infected skin graft was excised. Histologic examination of the failed graft revealed skin with surface ulceration, focal abscess formation, deep penetrating acute and chronic inflammation with numerous eosinophils, and granulomatous changes demonstrating a foreign body-type reaction to fungal hyphae (highlighted by periodic acid-Schiff staining, Figures 1A-E). The patient's past medical history included scoliosis, acute lower back pain, right shoulder degenerative joint disease, atopic dermatitis, lymphadenitis, rhonchi, insomnia, depression, and a long history of recurrent infections, particularly cutaneous staphylococcal and candida albicans infections, often accompanied by a purulent drainage. Review of the patient's laboratory studies revealed chronically elevated alkaline phosphatase, with highly elevated serum IgE (2,922 IU/ml) and eosinophilia (925/µL3) since childhood. Other lab studies were unremarkable, except for episodic elevations of the white blood cell count. The patient's family history was largely unremarkable and the patient's parents and siblings had no histories of unusual infections.

Risk factors perceived predictive of ISA spread in Chile: applications to decision support.

Aquaculture is anticipated to be a critical element in future solutions to global food shortage. However, diseases can impede industry efficiency and sustainability. Consequently, diseases can and have led to dramatic re-structuring in industry or regulatory practices. The emergence of infectious salmon anemia (ISA) in Chile is one such example. As in other countries, many mitigations were instituted universally, and many incurred considerable costs as they introduced a new layer of coordination of farming activities of marine sites within common geographic areas (termed 'neighborhoods' or 'barrios'). The aggregate response led to a strong reduction in ISA incidence and impact. However, the relative value of individual mitigations is less clear, especially where response policies were universally applied and retrospective analyses are missing 'controls' (i.e., areas where a mitigation was not applied). Further, re-focusing policies around disease prevention following resolution of an outbreak is important to renew sustainable production; though, again, field data to guide this shift in purpose are often lacking. Expert panels can offer timely decision support in the absence of empirical data. We convened a panel of fish health experts to weight risk factors predictive of ISA virus (ISAV) introduction or spread between Atlantic salmon barrios in Chile. Barrios, rather than sites, were the unit of interest because many of the new mitigations operate at this level and few available studies examine their efficacy. Panelists identified barrio processing plant biosecurity, fallowing strategies, adult live fish transfers, fish and site density, smolt quality, hydrographic connection with other neighborhoods, presence of sea lice (Caligus rogercresseyi), and harvest vessel biosecurity as factors with the greatest predictive strength for ISAV virulent genotype ('HPR-deleted') occurrence. Fewer factors were considered predictive of ISAV HPR0 genotype ('HPR0') occurrence, with greatest strengths assigned to fish and site density, adult live fish transfers, and smolt facility HPR0 status. Field validation based on ISAV and risk factor occurrence after panel completion generally supports expert estimates, and highlights a few factors (e.g., broodstock HPR0 status) less conclusive in the original study. Results inform legislation, industry best management practices and surveillance design.