Absence of Leishmania spp. DNA in road-killed wild mammals in Southern Brazil.

Leishmaniasis are neglected diseases transmitted by vectors that affect domestic and wild animals, including humans. Due to its incidence and lethality, this zoonosis is a worrying public health problem, making it essential to identify all links in the transmission chain. Infection of wild mammals by Leishmania spp. remains poorly understood, especially in southern Brazil. Therefore, the objective was to research, using the PCR technique, the presence of Leishmania spp. DNA in road-killed wild mammals in Southern Brazil. Carcasses of 96 animals were collected from highways in the Pelotas microregion, Rio Grande do Sul, southern Brazil and subjected to necropsies. Tissue fragments (spleen, skin, liver, kidney, heart, lung, lymph nodes, bone marrow and blood) were collected and genomic DNA was extracted. PCR protocols targeting the ITS1, kDNA and 18S genes were tested. We found no evidence of Leishmania spp. circulation in the studied population. However, epidemiological studies like this one are of great relevance, as they allow monitoring of the occurrence of pathogens and help identify possible risk areas. As these animals act as epidemiological markers for the presence of the microorganism, studies must be carried out continuously to understand whether there are sources of infection in the region.

Description of the parasitic fauna of a specimen of Didelphis albiventris at Rio Grande do Sul.

Didelphis albiventris is considered the most common marsupial in Rio Grande do Sul. With omnivorous and synanthropic habits, it can serve as a host to various parasites, playing an important role in maintaining their biological cycle. Despite being a widespread and abundant species, it has a relatively little-known parasitic fauna. Therefore, the aim of this study was to report the diversity of parasites in a fecal sample from D. albiventris in Rio Grande do Sul, Southern Brazil. Modified Centrifugal-flotation and Spontaneous sedimentation techniques were used, revealing a high taxonomic diversity of parasites. Eggs of Ancylostoma spp., Toxocara spp., and Anoplocephalidae were reported for the first time in the host in the southern region of the country, along with the first report of pseudoparasitism by Syphacia spp. and Monocystis spp. in this animal species. The presence of different parasites in the feces of D. albiventris is of utmost importance, primarily for public health, but also for understanding the biodiversity of parasites present in wildlife, which has been poorly studied until now. This allows the implementation of effective strategies for controlling, preventing and treating these diseases.

Didelphis albiventris é considerado o marsupial mais comum no Rio Grande do Sul. Com hábitos onívoros e sinantrópicos, pode servir de hospedeiro para diversos parasitas, desempenhando importante papel na manutenção do seu ciclo biológico. Apesar de ser uma espécie difundida e abundante, possui uma fauna parasitária relativamente pouco conhecida. Portanto, o objetivo deste estudo foi relatar a diversidade de parasitas em uma amostra fecal de D. albiventris no Rio Grande do Sul, Sul do Brasil. Foram utilizadas técnicas modificadas de flutuação centrífuga e sedimentação espontânea, revelando uma alta diversidade taxonômica de parasitas. Ovos de Ancylostoma spp., Toxocara spp. e Anoplocephalidae foram relatados pela primeira vez no hospedeiro na região sul do país, juntamente com o primeiro relato de pseudoparasitismo por Syphacia spp. e Monocystis spp. nesta espécie animal. A presença de diferentes parasitas nas fezes de D. albiventris é de extrema importância, principalmente para a saúde pública, mas também para a compreensão da biodiversidade de parasitas presentes na vida selvagem, que tem sido pouco estudada até agora. Isto permite a implementação de estratégias eficazes para controlar, prevenir e tratar estas doenças.

Absence of Leishmania spp. DNA in road-killed wild mammals in Southern Brazil / Ausência de DNA de Leishmania spp. em mamíferos silvestres atropelados no Sul do Brasil

Abstract Leishmaniasis are neglected diseases transmitted by vectors that affect domestic and wild animals, including humans. Due to its incidence and lethality, this zoonosis is a worrying public health problem, making it essential to identify all links in the transmission chain. Infection of wild mammals by Leishmania spp. remains poorly understood, especially in southern Brazil. Therefore, the objective was to research, using the PCR technique, the presence of Leishmania spp. DNA in road-killed wild mammals in Southern Brazil. Carcasses of 96 animals were collected from highways in the Pelotas microregion, Rio Grande do Sul, southern Brazil and subjected to necropsies. Tissue fragments (spleen, skin, liver, kidney, heart, lung, lymph nodes, bone marrow and blood) were collected and genomic DNA was extracted. PCR protocols targeting the ITS1, kDNA and 18S genes were tested. We found no evidence of Leishmania spp. circulation in the studied population. However, epidemiological studies like this one are of great relevance, as they allow monitoring of the occurrence of pathogens and help identify possible risk areas. As these animals act as epidemiological markers for the presence of the microorganism, studies must be carried out continuously to understand whether there are sources of infection in the region.

Resumo As leishmanioses são doenças negligenciadas, transmitidas por vetores que acometem animais domésticos e silvestres, incluindo os humanos. Devido a sua incidência e letalidade, essa zoonose consiste em um problema de saúde pública preocupante, sendo fundamental a identificação de todos os elos da cadeia de transmissão. A infecção de mamíferos silvestres por Leishmania spp. permanece pouco compreendida, especialmente no sul do Brasil. Portanto, objetivou-se pesquisar, por meio da técnica de PCR, a presença de DNA de Leishmania spp. em mamíferos silvestres atropelados no Sul do Brasil. Carcaças de 96 animais foram coletadas, em rodovias da microrregião de Pelotas, Rio Grande do Sul, sul do Brasil e submetidas a necropsias. Fragmentos de tecidos (baço, pele, fígado, rim, coração, pulmão, linfonodos, medula óssea e sangue) foram coletados e o DNA genômico foi extraído. Protocolos de PCR visando os genes ITS1, kDNA e 18S foram testados. Não foram encontradas evidências de circulação de Leishmania spp. na população estudada. Porém, estudos epidemiológicos como este são de grande relevância, pois permitem monitorar a ocorrência de patógenos e auxiliam na identificação de possíveis áreas de risco. Como esses animais atuam como marcadores epidemiológicos da presença do microrganismo, estudos devem ser realizados continuamente, para entender se existem fontes de infecção na região.

Ctenocephalides felis (Siphonaptera, Pulicidae) parasitizing White-eared opossum (Didelphis albiventris) at Southern Brazil - Case report.

Didelphis albiventris is a marsupial with synanthropic habits, whose contact with domestic animals and humans is increasing. They are considered potential disseminators of diseases, present as definitive hosts or reservoirs of various pathogenic agents. The present study aim to report, for the first time, the parasitism by Ctenocephalides felis in D. albiventris in Rio Grande, Southern Rio Grande do Sul state, Brazil. An adult female White-eared Opossum (D. albiventris), killed by being run over, was collected on the roads of the city of Rio Grande, Rio Grande do Sul, Brazil and sent to the laboratory for necropsy. During external inspection, a flea was found, which was stored in 70o alcohol until taxonomic identification, being classified as C. felis. This study reports the occurrence of parasitism by C. felis in D. albiventris for the first time in the location studied, demonstrating that these arthropods circulate between the wild and urban environments, and play an important role in the cycle of zoonotic pathogens among wild fauna, companion animals and humans.

Didelphis albiventris é um marsupial de hábitos sinantrópicos, cujo contato com animais domésticos e humanos está aumentando. São considerados potenciais disseminadores de doenças, apresentando-se como hospedeiros definitivos ou reservatórios de vários agentes patogênicos. O presente estudo tem como objetivo relatar, pela primeira vez, o parasitismo por Ctenocephalides felis em D. albiventris em Rio Grande, Sul do Rio Grande do Sul, Brasil. Uma fêmea adulta de gambá-de-orelha-branca (D. albiventris), morta por atropelamento, foi recolhida nas estradas da cidade de Rio Grande, Rio Grande do Sul, Brasil e encaminhado ao laboratório para necropsia. Durante inspeção externa foi encontrada uma pulga que foi armazenada em álcool 70º até a identificação taxonômica sendo classificado como C. felis. Este estudo relata a ocorrência de parasitismo por C. felis em D. albiventris para o primeira vez no local estudado, demonstrando que esses artrópodes circulam entre a natureza e ambientes urbanos e desempenham um papel importante no ciclo de patógenos zoonóticos entre a fauna selvagem, animais de companhia e humanos.

Effect of Electrical Stimulation on PC12 Cells Cultured in Different Hydrogels: Basis for the Development of Biomaterials in Peripheral Nerve Tissue Engineering.

Extensive damage to peripheral nerves is a health problem with few therapeutic alternatives. In this context, the development of tissue engineering seeks to obtain materials that can help recreate environments conducive to cellular development and functional repair of peripheral nerves. Different hydrogels have been studied and presented as alternatives for future treatments to emulate the morphological characteristics of nerves. Along with this, other research proposes the need to incorporate electrical stimuli into treatments as agents that promote cell growth and differentiation; however, no precedent correlates the simultaneous effects of the types of hydrogel and electrical stimuli. This research evaluates the neural differentiation of PC12 cells, relating the effect of collagen, alginate, GelMA, and PEGDA hydrogels with electrical stimulation modulated in four different ways. Our results show significant correlations for different cultivation conditions. Electrical stimuli significantly increase neural differentiation for specific experimental conditions dependent on electrical frequency, not voltage. These backgrounds allow new material treatment schemes to be formulated through electrical stimulation in peripheral nerve tissue engineering.

First report of parasitism by Eutrichophilus cercolabes (Phthiraptera: Trichodectidae) on Coendou spinosus (Erethizontidae) in Rio Grande do Sul, Brazil - case report.

Coendou spinosus is a species of rodent popularly known as porcupine, it has a great ability to adapt to different habitats and is found in tropical forests in countries such as Bolivia, Brazil, Venezuela and Guianas. This mammal has already been identified as a reservoir of several pathogenic agents for humans and other animals and has a variety of ectoparasites, endoparasites and hemoparasites little studied and described. Due to this, the objective was to report the parasitism by Eutrichophilus cercolabes in C. spinosus in the central region of Rio Grande do Sul, southern Brazil. In total, 16 lice were found, one male and 15 females of the species. This is the first report of the parasitism of this Phthiraptera on C. spinosus in Rio Grande do Sul. The scarcity of reports on the taxonomy and biotic characteristics, as well as the vector capacity of pathogens of most species of ectoparasites of wild animals, highlights the need for further studies on the distribution of these arthropods in different regions and host species.

Coendou spinosus é uma espécie de roedor conhecida popularmente por porco-espinho, possui uma grande capacidade de adaptação a diferentes habitats sendo encontrada em florestas tropicais de países como Bolívia, Brasil, Venezuela e Guianas. Esse mamífero já foi identificado como reservatório de vários agentes patogênicos para o homem e outros animais e possui uma variedade de ectoparasitos, endoparasitos e hemoparasitos pouco estudados e descritos. Devido a isso, objetivou-se relatar o parasitismo por Eutrichophilus cercolabes em C. spinosus na região central do Rio Grande do Sul, Sul do Brasil. Ao total, foram encontrados 16 piolhos, sendo um macho e 15 fêmeas da espécie. Esse é o primeiro relato do parasitismo deste Phthiraptera em C. spinosus no Rio Grande do Sul. A escassez de relatos sobre a taxonomia e características bióticas, bem como a capacidade vetorial de patógenos da maioria das espécies de ectoparasitos de animais silvestres evidencia a necessidade da realização de mais estudos sobre a distribuição desses artrópodes em diferentes regiões e espécies hospedeiras.

Tratamiento endovascular de fístula carotídea yugular por catéter de diálisis con stent cubierto autoexpandible / Endovascular treatment with autoexpandible stentgraft for jugular-carotid fistula after dialysis catheter misplacement

Paciente masculino de 59 años con antecedentes de obesidad, hipertensión arterial y enfermedad renal crónica que presentó fracaso renal agudo de su riñón trasplantado, que requirió la colocación de un catéter transitorio. Durante la colocación de un catéter 12 Fr guiado por ecografía, inadvertidamente se realizó una fístula carotídea yugular (FYC). Después de que fallara la compresión guiada por ultrasonido, se desplegó en la carótida primitiva un stent autoexpandible cubierto con exclusión defi nitiva de la fístula. Estos resultan una opción segura y factible para el tratamiento de la fístula yugular carotídea en zonas de exposición quirúrgica complicada y pacientes de alto riesgo.(AU)

A 59-year-old male patient with a history of obesity, high blood pressure, and chronic kidney disease who presented acute renal failure of his transplanted kidney, requiring temporary catheter placement. During the placement of a 12 Fr catheter guided by ultrasound, a jugular-carotid fi stula (JCF) was inadvertently created. After ultrasound-guided compression failed, a covered self-expanding stent was deployed in the common carotid with defi nitive exclusion of the fi stula. These are a safe and feasible option for the treatment of carotid jugular fi stula in areas with complicated surgical exposure and for high-risk patients.(AU)

Culicoides' species from a Leishmania transmission hotspot and efficacy of the Captor® suction light trap.

Culicoides have medical and veterinary importance, as they play a role as vectors of viruses, protozoa, and nematodes that cause diseases. Despite the relevance to public health, greater attention has been given to other insect vectors. Therefore, the objective of this study was to evaluate the efficiency of the Captor® light trap in capturing Culicoides that could be examined for the presence of Leishmania DNA. The insects were captured in a rural area of Santa Maria, Rio Grande do Sul, Brazil, where canine and human visceral leishmaniasis have been diagnosed. Adult insects were collected weekly, from 6:00 pm to 6:00 am, for a 12 month period using a Captor® brand suction light trap. All Culicoides were identified at species level. Pools of Culicoides were tested using the Polymerase Chain Reaction (PCR) technique for the detection of Leishmania DNA. A total of 16,016 specimens were collected (71.54% females and 28.39% males), divided among seven species. In the DNA analysis, none of the pools showed a positive result for Leishmania. The data presented demonstrate that the trap is efficient and can be an alternative for use in entomological research. They also demonstrate that, despite the females having hematophagous habits, similar to other vector insects, they did not have contact with Leishmania in the studied locality.

Culicoides têm importância médica e veterinária, pois desempenham um papel como vetores de vírus, protozoários e nematoides que causam doenças em animais e humanos. Apesar da relevância para a saúde pública, maior atenção tem sido dada a outros insetos vetores. Portanto, o objetivo do estudo foi avaliar a eficiência da armadilha luminosa Captor® na captura de Culicoides que pudesse ser verificada quanto à presença de DNA de Leishmania. Os insetos foram capturados em uma área rural de Santa Maria, Rio Grande do Sul, Brasil, onde foram diagnosticadas leishmaniose visceral canina e humana. Os insetos adultos foram coletados semanalmente, das 18h às 6h, com armadilha luminosa de sucção da marca Captor® por doze meses. Todos Culicoides foram identificados em nível de espécie. Pools de Culicoides foram testados pela técnica de PCR para detecção de DNA de Leishmania. Foram coletados 16.016 espécimes (71,54% fêmeas e 28,39% machos), divididos em sete espécies. Na análise de DNA, nenhum dos pools apresentou resultado positivo para Leishmania. Os dados apresentados demonstram que a armadilha é eficiente e pode ser uma alternativa para uso em pesquisas entomológicas. Demonstram também que, apesar das fêmeas apresentarem hábitos hematófagos, semelhantes a outros insetos vetores, não tiveram contato com Leishmania na localidade estudada.

A new analytical model for the response curve in megavoltage photon beams of the radiochromic EBT3 films measured with flatbed scanners.

PURPOSE: The aim of this work is to study a new analytical model which describes the dose-response curve in megavoltage photon beams of the radiochromic EBT3 film measured with two commercially available flatbed scanners. This model takes into account the different increase of the number of two types of absorbents in the film with absorbed dose and it allows to identify parameters that depend on the flatbed scanner and the film model, and parameters that exclusively depend on the production lot. In addition, the new model is also compared with other models commonly used in the literature in terms of its performance in reducing systematic calibration uncertainties. METHODS AND MATERIALS: The new analytical model consists on a linear combination of two saturating exponential functions for every color channel. The exponents modeling the growing of each kind of absorbent are film model and scanner model-dependent, but they do not depend on the manufacturing lot. The proposed model considers the different dose kinetics of each absorbent and the apparent effective behavior of one of the absorbents in the red color channel of the scanner. The dose-response curve has been measured using EBT3 films, a percentage depth dose (PDD) calibration method in a dose range between 0.5 and 25 Gy, and two flatbed scanners: a Microtek 1000 XL and an EPSON 11000 XL. The PDD calibration method allows to obtain a dense collection of calibration points which have been fitted to the proposed response curve model and to other published models. The fit residuals were used to evaluate the performance of each model compared with the new analytical model. RESULTS: The model presented here does not introduce any systematic deviations up to the degree of accuracy reached in this work. The residual distribution is normally shaped and with lower variance than the distributions of the other published models. The model separates the parameters reflecting specific characteristics of the dosimetry system from the linear parameters which depend only on the production lot and are related to the relative abundance of each type of absorbent. The calibration uncertainty is reduced by a mean factor of two by using this model compared with the other studied models. CONCLUSIONS: The proposed model reduces the calibration uncertainty related to systematic deviations introduced by the response curve. In addition, it separates parameters depending on the flatbed scanner and the film model from those depending on the production lot exclusively and therefore provides a better characterization of the dosimetry system and increases its reliability.

Recommendations for the diagnosis and management of persons with suspected vaccine-induced immune thrombotic thrombocytopenia (VITT) / Recomendaciones para diagnostico y manejo de personas con trombocitopenia trombotica inmune inducida por vacunas (VITT)

Abstract In recent months, rare cases of thrombosis at unusual sites associated with thrombocytopenia, occurring within a typical risk window (i.e., 4-28 days) after receiving SARS CoV2 vaccines, have been reported. Healthcare professionals should be prepared to detect these cases on time. The Expert Panel of the Knowledge Management and Transfer Network conducted a free search of the related literature. With the available information and the clinical expertise of the working group, we formulated, reviewed, and endorsed recommendations for the timely suspicion, diagnosis (case definitions, the use of initial laboratory and imaging tests, specific tests), and management of these thrombotic conditions. This document is considered a living document that will be updated as new evidence emerges, and recommendations may change over time.

Resumen En meses recientes se han reportado casos raros de trombocitopenia y trombosis en sitios inusuales, que ocurren dentro de una ventana de riesgo típica ( por ejemplo de 4 a 28 días) luego de recibir vacunas de SARS CoV 2. Los profesionales de la salud deben estar preparados para detectar estos casos a tiempo. Un panel de expertos y una red de transferencia de conocimiento realizó una búsqueda libre de literatura seleccionada. Con la información disponible y la experticia clínica del grupo de trabajo revisamos y dimos recomendaciones para la sospecha temprana, el diagnostico (definición de caso, el uso de pruebas de laboratorio especificas y de imágenes diagnósticas) para le manejo de estas condiciones tromboticas. Este documento es considerado un documento vivo que debe ser actualizado a medida que surja nueva evidencia y las recomendaciones vayan cambiando con el tiempo

Antiphospholipid syndrome-mediated acute cerebrovascular diseases and long-term outcomes.

OBJECTIVES: The antiphospholipid syndrome (APS) is an autoimmune disease associated with thrombotic and non-thrombotic neurologic manifestations. APS is classified as primary (PAPS) or secondary (SAPS) when it co-exists with another autoimmune disease. We aim to describe the spectrum of acute cerebrovascular disease among patients with APS, their differences between stroke subtypes, and long-term functional outcomes. METHODS: Retrospective cohort study including adult (≥18 years) patients with APS followed in the stroke clinic of a tertiary-care reference center for autoimmune diseases in Mexico from 2009 to 2019. RESULTS: We studied 120 cases; 99 (82.5%) women; median age 43 years (interquartile range 35-52); 63.3% with SAPS. Demographics, comorbidities, and antiphospholipid antibodies (aPL) positivity were similar between APS type and stroke subtypes. Amongst index events, we observed 84 (70%) acute ischemic strokes (AIS), 19 (15.8%) cerebral venous thromboses (CVT), 11 (9.2%) intracerebral hemorrhages (ICH), and six (5%) subarachnoid hemorrhages (SAH). Sixty-seven (55.8%) were known patients with APS; the median time from APS diagnosis to index stroke was 46 months (interquartile range 12-96); 64.7% of intracranial hemorrhages (ICH or SAH) occurred ≥4 years after APS was diagnosed (23.5% anticoagulation-related); 63.2% of CVT cases developed before APS was diagnosed or simultaneously. Recurrences occurred in 26 (22.8%) patients, AIS, in 18 (69.2%); intracranial hemorrhage, in eight (30.8%). Long-term functional outcomes were good (modified Rankin Scale ≤2) in 63.2% of cases, during follow-up, the all-cause mortality rate was 19.2%. CONCLUSION: We found no differences between stroke subtypes and APS types. aPL profiles were not associated with any of the acute cerebrovascular diseases described in this cohort. CVT may be an initial thrombotic manifestation of APS with low mortality and good long-term functional outcome.

Cloud architecture for electronic health record systems interoperability.

BACKGROUND: Current Electronic Health Record (EHR) systems are built using different data representation and information models, which makes difficult achieving information exchange. OBJECTIVE: Our aim was to propose a scalable architecture that allows the integration of information from different EHR systems. METHODS: A cloud-based EHR interoperable architecture is proposed through the standardization and integration of patient electronic health records. The data is stored in a cloud repository with high availability features. Stakeholders can retrieve the patient EHR by requesting only to the integrated data repository. The OpenEHR two-level approach is applied according to the HL7-FHIR standards. We validated our architecture by comparing it with 5 different works (CHISTAR, ARIEN, DIRAYA, LLPHR and INEHRIS) using a set of selected axes and a scoring method. RESULTS: The problem was reduced to a single point of communication between each EHR system and the integrated data repository. By combining cloud computing paradigm with selected health informatics standards, we obtained a generic and scalable architecture that complies 100% with interoperability requisites according to the evaluation framework applied. CONCLUSIONS: The architecture allowed the integration of several EHR systems, adapting them with the use of standards and ensuring the availability thanks to cloud computing features.

On the Relation Between Over-Indebtedness and Well-Being: An Analysis of the Mechanisms Influencing Health, Sleep, Life Satisfaction, and Emotional Well-Being.

This paper aims to explore the association between over-indebtedness and two facets of well-being - life satisfaction and emotional well-being. Although prior research has associated over-indebtedness with lower life satisfaction, this study contributes to the extant literature by revealing its effects on emotional well-being, which is a crucial component of well-being that has received less attention. Besides subjective well-being (SWB), reported health, and sleep quality were also assessed. The findings suggest that over-indebted (compared to non-over-indebted) consumers have lower life satisfaction and emotional well-being, as well as poorer (reported) health and sleep quality. Furthermore, over-indebtedness impacts life satisfaction and emotional well-being through different mechanisms. Consumers decreased perceived control accounts for the impact of over-indebtedness on both facets of well-being (as well as on reported health and sleep). Financial well-being (a specific component of life satisfaction), partly mediates the impact of indebtedness status on overall life satisfaction. The current study contributes to research focusing on the relationship between indebtedness, well-being, health, and sleep quality, and provides relevant theoretical and practical implications.

Using artificial intelligence to overcome over-indebtedness and fight poverty.

This research examines how artificial intelligence may contribute to better understanding and to overcome over-indebtedness in contexts of high poverty risk. This research uses Automated Machine Learning (AutoML) in a field database of 1654 over-indebted households to identify distinguishable clusters and to predict its risk factors. First, unsupervised machine learning using Self-Organizing Maps generated three over-indebtedness clusters: low-income (31.27%), low credit control (37.40%), and crisis-affected households (31.33%). Second, supervised machine learning with exhaustive grid search hyperparameters (32,730 predictive models) suggests that Nu-Support Vector Machine had the best accuracy in predicting families' over-indebtedness risk factors (89.5%). By proposing an AutoML approach on over-indebtedness, our research adds both theoretically and methodologically to current models of scarcity with important practical implications for business research and society. Our findings also contribute to novel ways to identify and characterize poverty risk in earlier stages, allowing customized interventions for different profiles of over-indebtedness.

A new approach to radiochromic film dosimetry based on non-local means.

Radiochromic film in conjunction with flatbed scanners are frequently employed as dosimeters for advanced techniques in radiotherapy. Their strengths are as follows: light element composition, low energy dependence, near biological tissue equivalence and high spatial resolution. However, they have some weaknesses as well: non-uniformities, read out noise, and scanning artifacts. Several processing protocols have been proposed intending to correct the perturbations these weaknesses produce. The aim of this paper is to present a new processing protocol for radiochromic film dosimetry based on a non-local means denoising algorithm. Three dose distributions of open square fields and a spatial combination of these fields using different angles of incidence and monitor units have been employed to validate the protocol. The dose distributions are traceable to ionization chamber measurements. Additionally, a real dose distribution of a treatment was used to simulate scanning data with noise and scanning lateral artifact, and to study how the protocol behaves under these perturbations. The same measured raw data have been processed by means of an implementation of the multichannel protocol (multigaussian method). It has been found that the proposed protocol reduces dose uncertainty even though it uses fewer scans than the multichannel protocol.

Metodologías cuantitativas: Cálculo del tamaño de muestra con STATA y R / Quantitative methods: Sample size calculation with STATA and R

El cálculo de tamaño de muestra es un aspecto esencial del diseño de estudios cuantitativos. Un adecuado tamaño de muestra nos permite determinar cuál es la mínima cantidad de participantes necesarios para probar nuestra hipótesis de interés. De esta manera, podemos reducir costos, maximizar el uso de nuestros recursos de investigación y garantizar la factibilidad del estudio. Contradictoriamente, a pesar de su relevancia muy pocos investigadores dominan esta habilidad. Esta revisión tiene por objeto revisar los conceptos básicos para realizar un cálculo de tamaño de muestra y compartir códigos de Stata y R específicamente diseñados para facilitar estos cálculos.

The calculation of sample size is an essential aspect of the design of quantitative studies. An adequate sample size allows us to determine the minimum number of participants necessary to test our hypothesis of interest. Hence, we can reduce costs, maximize the use of our research resources and guarantee the feasibility of the study. Contradictorily, despite its relevance, very few researchers dominate this skill. This review aims to review the basics of sample size calculation and share Stata and R codes specifically designed to facilitate these calculations.

Recomendaciones para el uso racional de la prueba 25-hidroxivitamina D Resumen de política

está disponible en el texto completo

The exponential increase in the request for laboratory tests of 25-Hydroxyvitamin D or [25 (OH) D has ignited the alarms and generated a strong call for attention, since it may reflect deficiencies in the standardization of clinical practice and in the use non-systematic scientific evidence for decision-making in real life, which allows to analyze the indications of the test, its frequency, interpretation and even to assess the impact for health systems, especially when contrasted with the minimum or almost. No effects of the strategy of screening or supplying indiscriminately to the general population, without considering a comprehensive clinical assessment of risks and needs of people. From a purely public health impact point of view, the consequence of massive and unspecified requests is affecting most of the health systems and institutions at the global level. The primary studies that determined average population intake values have been widely used in the formulation of recommendations in Clinical Practice Guidelines, but unfortunately misinterpreted as cut points to diagnose disease and allow the exaggerated prescription of nutritional substitution. The coefficient of variation in routine tests to measure blood levels of 25 (OH) D is high (28%), decreasing the overall accuracy of the test and simultaneously, increasing both the falsely high and falsely low values. The most recent scientific evidence analyzes and seriously questions the usefulness and the real effect of the massive and indiscriminate practice of prescribing vitamin D without an exhaustive risk analysis. The available evidence is insufficient to recommend a general substitution of vitamin D to prevent fractures, falls, changes in bone mineral density, incidence of cardiovascular diseases, cerebrovascular disease, neoplasms and also to modify the growth curve of mothers' children. They received vitamin D as a substitute during pregnancy. The recommendations presented in the document are based on the critical analysis of current evidence and the principles of good clinical practice and invite to consider a rational use of 25 (OH) D tests in the context of a clinical practice focused on people and a comprehensive assessment of needs and risks. The principles of good practice suggest that clinicians may be able to justify that the results of the 25 (OH) D test strongly influence and define clinical practice and modify the outcomes that interest people and impact their health and wellness. Currently there is no clarity on how to interpret the results, and the relationship between symptoms and 25 (OH) D levels, which may not be consistent with the high prevalence of vitamin D deficiency reported. For this reason, it is suggested to review the rationale of the request for tests for systematic monitoring of levels of 25 (OH) D or in all cases where substitution is performed. Consider the use of 25 (OH) D tests within the comprehensive evaluation of people with suspicion or confirmation of the following conditions: rickets, osteomalacia, osteoporosis, hyper or hypoparathyroidism, malabsorption syndromes, sarcopenia, metabolic bone disease.