Abstract We investigated the Biogran on bone repair and metabolism at several time-intervals upon grafting into rat tibia artificial defects. The biomaterial was thoroughly characterized in vitro, and its dissolution behavior upon immersion was assessed in simulated body fluid (SBF) solution for 1, 3, 7, 14, and 30 days. Biogran was also assessed by in vitro hydroxyapatite formation in SBF solution, which is a marker for bioactive behavior. In vivo, distal and proximal bone defects were performed in the Wistar rat's right tibia and filled according to the experimental groups: I) negative control, no filling; II) positive control, 10 mg of autogenous bone; and III) 10 mg of Biogran. Animals were euthanized at 1, 2, 3, 4, 7, and 10 weeks. Bone neoformation was analyzed using histomorphometry (proximal defect), and local levels of bone morphogenetic protein 2 (BMP-2) were measured using the ELISA assay (distal defect). In vitro, the Biogran sample showed a fast dissolution rate within the first 7 days, parallel to the formation of the hydroxyapatite layer. In vivo, the sample was progressively resorbed at a higher rate within the first month until it became almost absent at week 10th. The sample presented similar or higher bone neoformation concerning the autogenous bone. BMP-2 levels were sustained in the Biogran group (around 200 pg/mg) and detected until the last experimental time with a significant difference compared with the controls. Results suggest Biogran is a candidate for hard tissue engineering even in highly active bone remodeling sites.

Abstract This article aimed to map therapeutic itineraries in health care within rural Quilombola communities in the north of Minas Gerais, Brazil. This is a section of a qualitative research conducted in six visited communities. The data was collected through 18 individual interviews, analyzed using the theoretical-methodological framework of Therapeutic Itineraries, and organized into three empirical themes. The narratives allowed for understanding the paths taken in health care by the Quilombola population, identifying the components of the popular subsystem (natural resources, the use of teas and home remedies), the family subsystem (transmission of knowledge and cultural heritage of care), and the professional subsystem (hospital level, medical care, primary and specialized attention). The difficulties of access are not only due to geographical distances, but also broader aspects of social determination, such as institutional racism, low availability of services, the need for payment for transportation and medical procedures. In this sense, it is necessary to have an approach and interventions from public policies to address ethnic-racial, economic, and access inequalities in health care services.

Resumo Este artigo teve como objetivo mapear os itinerários terapêuticos no cuidado em saúde em comunidades quilombolas rurais no norte de Minas Gerais, Brasil. Trata-se de um recorte de uma pesquisa qualitativa realizada em seis comunidades visitadas. Os dados foram produzidos por meio de 18 entrevistas individuais, analisados pelo referencial teórico-metodológico dos itinerários terapêuticos e organizados em três temas empíricos. As narrativas permitiram a compreensão dos percursos trilhados no cuidado em saúde pela população quilombola, a identificação dos componentes do subsistema popular (recursos naturais, o uso de chás e remédios caseiros), do subsistema familiar (transmissão de conhecimentos e herança cultural de cuidados), e do subsistema profissional (nível hospitalar, cuidados médicos, atenção primária e especializada). As dificuldades de acesso não decorrem apenas das distâncias geográficas, envolvem aspectos mais amplos da determinação social, como o racismo institucional, a baixa oferta de serviços, a necessidade de pagamento para deslocamentos e procedimentos médicos. Nesse sentido, fazem-se necessárias uma abordagem e intervenções das políticas públicas frente às desigualdades étnico-raciais, econômicas e de acesso aos serviços de cuidado em saúde.

ABSTRACT Numerous tests employed to predict cardiac and functional status are expensive and not widely accessible for a considerable number of patients, particularly those diagnosed with Chagas disease (CD) residing in remote and endemic regions. To date, there is no knowledge of studies that have validated instruments that address functionality in an expanded way, including the biopsychosocial factors in patients with CD. This study aims to evaluate the psychometric properties of the World Health Organization Disability Assessment Schedule (WHODAS 2.0), in its 12-item shortened version (WHODAS-12) when applied to patients with CD. This is a cross-sectional study of a prospective cohort that follows individuals with CD (SaMi-Trop). Data collection took place between October 2019 and March 2020. In the interviews, sociodemographic information, life habits, clinical information, and indicators of disability measured by WHODAS-12 were collected. Descriptive analysis, internal consistency and construct validity of the instrument were performed. A total of 628 patients with CD were interviewed, most were women (69.5%), their mean age was of 57 years, and most declared an average self-perception of health (43.4%). The 12 items of WHODAS-12 were distributed into three factors, which together account for 61% of the variance. The Kaiser–Meyer–Olkin (KMO) index was 0.90, indicating adequacy of the sample for factor analysis. The internal consistency of the global scale showed alpha = 0.87. The percentage of incapacity was 16.05%, indicating mild incapacity for the evaluated patients. WHODAS-12 is a valid and reliable measure to assess the disability of the Brazilian population with CD.

Abstract Background Cardiovascular risk factors are prognostic factors in coronavirus disease 2019 (COVID-19) and have been scarcely studied in Brazil. Objective The aim of this study was to assess the impact of cardiovascular risk factors on the outcomes of patients admitted for COVID-19. Methods From July 2020 to February 2021, 200 patients from two public hospitals were enrolled. Patients were included if they had typical symptoms or signs of COVID-19, a positive real-time polymerase chain reaction test (RT-PCR) for COVID-19, and an age above 18 years. This is a prospective, observational, and longitudinal study. Data were collected within 24 h of admission. The primary endpoint was a combination of hospital lethality, mechanical ventilation, hemodialysis, or length of hospital stay >28 days. Continuous variables were compared with the Student’s t-test for independent samples or the Mann-Whitney test. For comparisons of proportions, the χ 2 test was applied. ROC curves and survival curves were constructed. Multivariate logistic regression was performed to identify independent predictors of events. The level of significance was 0.05. Results There were 98 (49%) events during the hospital course, and 72 (36%) died in the hospital. Patients with a primary endpoint were older and more likely to have a history of hypertension, diabetes, chronic obstructive pulmonary disease (COPD), and chronic kidney disease (CKD). Vital signs at admission associated with events were diastolic blood pressure, respiratory rate, and oxygen saturation in ambient air (O 2 Sat). Serum creatinine >1.37 mg/dL at admission had a sensitivity of 51.6 and a specificity of 82% to predict the primary endpoint, with an area under the curve (AUC) of 0.68. In multivariate analysis, age, diabetes, CKD, and COPD were independent predictors of the primary endpoint. Age and CKD were independent predictors of in-hospital lethality. Conclusion Cardiovascular risk factors, such as diabetes and CKD, were related to a worse prognosis in patients hospitalized with COVID-19 in this sample from two public hospitals in the state of Rio de Janeiro.

Abstract: The thermoinhibition of lettuce seed germination causes important losses for producers, who do not have thermotolerant commercial cultivars. One of the obstacles has been the scarcity of optimizing techniques capable of efficiently discriminating thermotolerant and thermosensitive cultivars. The aim of this work was to evaluate the use of neural networks to discriminate different levels of thermoinhibition in lettuce seeds. Seeds of 18 cultivars were evaluated for thermoinhibition considering the characteristics of the first and last germination count and germination speed index, in seeds subjected to temperatures of 20, 25, 30 and 35 °C. The remaining seeds, which did not germinate, were subjected to the tetrazolium test. Analyses were performed immediately after seed harvesting and repeated after six months of storage. Discriminant analysis was performed and the Kohonen’s Self-Organizing Map (SOM) was created using Artificial Neural Networks (ANNs). Neural networks discriminate lettuce cultivars and organizes them in terms of seed thermoinhibition tolerance through Kohonen’s Self-Organizing Map. Discriminant analysis consistently identifies the Everglades and Luiza genotypes as tolerant to thermoinhibition.

Resumo: A termoinibição causa perdas importantes para os produtores, os quais não dispõem de cultivares comerciais com sementes termotolerantes. Há escassez de técnicas otimizadoras capazes de discriminar cultivares termotolerantes e termosensíveis com eficiência. Objetivou-se avaliar o uso de redes neurais para discriminar diferentes níveis de termoinibição em sementes de alface. Foram avaliadas sementes de 18 cultivares quanto à termoinibição considerando às características de primeira e última contagem de germinação e índice de velocidade de germinação, em sementes submetidas às temperaturas de 20, 25, 30 e 35 °C. As sementes remanescentes, que não germinaram, foram submetidas ao teste de tetrazólio. As análises foram realizadas imediatamente após a colheita das sementes e repetidas após seis meses de armazenamento. Uma análise discriminante e o Mapa Auto-Organizável de Kohonen (SOM) por Redes Neurais Artificiais (RNA’s) foram realizados. As redes neurais discriminam as cultivares de alface e as organiza quanto a tolerância a termoinibição das sementes por meio do Mapa Auto-Organizável de Kohonen. A análise discriminante indentifica de maneira coerente o genótipo Everglades e Luiza como tolerantes a termoinibição.

Abstract Introduction The immune reconstitution (IR) after the allogenic hematopoietic stem cell transplantation (allo-HSCT) is a progressive process intrinsically correlated to the therapeutic success. It is essential to understand the interfering factors in IR to prevent the HSCT-related mortality. Methods We retrospectively evaluated the clinical outcomes, absolute lymphocyte counts (ALCs) and lymphocyte subtypes at different time-points of 111 pediatric patients with allogeneic HSCT for malignant and non-malignant diseases from 2013 to 2018. Results The ALCs gradually increased on D+30, D+100, and D+180 (medians 634/μL, 1022/μL and 1541/μL, respectively). On D+100, the CD3+CD8+ achieved the highest recovery rate (68%), followed by the CD16+CD56+ (47%), CD3+CD4+ (39%) and CD19+ (8%). The adequate ALC recovery was associated with age < 8 years, bone marrow grafts, myeloablative conditioning, non-use of serotherapy and non-haploidentical donors. The ALC and CD3+CD8+ on D+100 counts were higher in patients with the cytomegalovirus infection. The CD3+CD4+ recovery was associated with an age < 8 years, a non-malignant disease and a lower incidence of acute graft-versus-host disease ≥ grade 2. Furthermore, the ALC recovery on D+100 resulted in a higher overall survival, regardless of the disease type (HR 3.65, 1.05 - 12.71, p= 0.04). Conclusion Several factors influenced the IR after the allo-HSCT. The ALC ≥ 500/μL on D+100 was a simple IR predictor of survival, easily available to resource-limited centers.

ABSTRACT The perception of Elementary School teachers about their mental health was the focus of this research. This is a quantitative research that seeks to understand the perceptions of mental health conditions in public schools in the interior of Rio Grande do Sul, Brazil. The data collection method used was a questionnaire adapted from the Mental Health and Work Protocol answered by 249 teachers. Data analysis was carried out using the Statistical Package for the Social Sciences - SPSS 18 software. It was found, as main results, that satisfaction, motivation and identity indices with the teaching activity are very significant. Teachers indicate commitment to work, value the profession, but complain that socially they are not valued, but paradoxically are heavily medicated.

RESUMEN La percepción de los docentes de educación básica sobre su salud mental fue el enfoque de esta investigación. El objetivo de esta investigación cuantitativa fue comprender de esas percepciones las condiciones de salud mental de escuelas públicas en el interior de RS, Brasil. El método de la recolecta de datos utilizado fue un cuestionario adaptado del Protocolo de Atención a la Salud Mental y Labor respondido por 249 profesores. Se realizó el análisis de los datos por intermedio del software Statistical Package for the Social Sciences - SPSS 18. Se encontró, como principales resultados, que índices de satisfacción, motivación e identidad con la actividad docente son muy significativos. Los profesores indican comprometimiento con el trabajo, valoran la profesión, pero se quejan de que socialmente no son valorizados, sin embargo, paradoxalmente están muy medicados.

RESUMO A percepção dos docentes de Ensino Fundamental sobre a sua saúde mental foi o foco desta pesquisa. Trata-se de uma pesquisa quantitativa que procura compreender as percepções das condições de saúde mental de escolas públicas no interior do Rio Grande do Sul, Brasil. O método da coleta de dados utilizado foi um questionário adaptado do Protocolo de Atenção à Saúde Mental e Trabalho respondido por 249 professores. Realizou-se a análise dos dados por intermédio do software Statistical Package for the Social Sciences - SPSS 18. Encontrou-se, como principais resultados, que índices de satisfação, motivação e identidade com a atividade docente são muito significativos. Os professores indicam comprometimento com o trabalho, valorizam a profissão, mas queixam-se de que socialmente não são valorizados, mas paradoxalmente estão muito medicados.

Abstract Tracheary elements can be classified as tracheids or vessel elements. In ferns, both cell types and even cells with intermediate characteristics can be observed. For a long time, the methods employed in the study of these cells were questioned and consequently their classification as well. In the present work, we analyze the stem tracheal elements of 13 Aspleniaceae species, occurring in different habitats and belonging to different clades. The samples were cut, dried on a hotplate, metallized, and analyzed in SEM. In general, the Asplenium species analyzed contain elongated conducting cells with oblique end walls, with scalariform thickening on all faces of the cell. The presence of pit membranes, however, varies greatly among species, it being possible to observe species with tracheids, with intermittent perforation plates, and with vessel elements.

Resumo Os elementos traqueais podem ser classificados como traqueídeos ou elementos de vaso. Nas samambaias podem ser observados ambos os tipos de células e até mesmo células com características intermediárias. Durante muito tempo os métodos empregados no estudo dessas células foram questionados e consequentemente a sua classificação também. No presente trabalho analisamos os elementos traqueais do caule de 13 espécies de Aspleniaceae, ocorrendo em diferentes habitats e pertencentes a diferentes clados. As amostras foram cortadas, secas em placa quente, metalizadas e analisadas em MEV. Em geral, as espécies de Asplenium analisadas contêm células condutoras alongadas com paredes terminais oblíquas, com espessamento escalariforme em todas as faces da célula. A presença de membranas de pontoações, entretanto, varia muito entre as espécies, sendo possível observar espécies com traqueídeos, com placas de perfuração intermitentes e com elementos de vasos.

ABSTRACT. Unpaid caregivers of people living with dementia tend to suffer mental health problems as a result of the negative effects associated with the care tasks. Thus, psychosocial interventions for this population group are necessary. iSupport is an online support program for caregivers that was created by the World Health Organization. Objective: To describe the design of a randomized clinical trial to measure the efficacy of the iSupport-Brasil version on caregivers’ mental health and well-being. Methods: The participants will be randomized into Intervention Group (IG) (n=195) and Control Group (CG) (n=195). For three months, the IG will access the iSupport-Brasil platform, the CG will enter the electronic page of the Brazilian Alzheimer’s Association, and both groups will be emailed the preliminary version of the “Guia de cuidados para a pessoa idosa” e-book (a guide to providing care to the elderly) from the Ministry of Health. The data will be collected at three moments: baseline, and three and six months after the beginning of the intervention. Results: It is expected that it will be possible to provide diverse validity evidence about iSupport-Brasil as an online and free intervention alternative, as a preventive means and as a way to promote mental health among caregivers of people living with dementia. Conclusion: Through the evaluation protocol of this randomized clinical trial on the effects of the iSupport-Brasil program, it may become a reference for countries that plan to adapt and improve the iSupport program using digital health solutions.

RESUMO. Cuidadores informais de pessoas que vivem com demência tendem a sofrer problemas de saúde mental como resultado dos efeitos negativos associados às tarefas de cuidado. Assim, intervenções psicossociais para essa população são necessárias. O iSupport é um programa de apoio online para cuidadores criado pela Organização Mundial da Saúde. Objetivo: Descrever o desenho de um ensaio clínico randomizado para medir a eficácia da versão iSupport-Brasil na saúde mental e no bem-estar de cuidadores. Métodos: Os participantes serão randomizados em Grupo Intervenção (GI) (n=195) e Grupo Controle (GC) (n=195). Durante três meses, o GI acessará a plataforma iSupport-Brasil, o CG entrará na página eletrônica da Associação Brasileira de Alzheimer e ambos os grupos receberão por e-mail a versão preliminar do e-book Guia de cuidados para a pessoa idosa, do Ministério da Saúde. Os dados serão coletados em três momentos: linha de base, três e seis meses após o início da intervenção. Resultados: Espera-se que seja possível fornecer diversas evidências sobre os efeitos do iSupport-Brasil como alternativa de intervenção online e gratuita, de forma a promover a saúde mental entre os cuidadores de pessoas que vivem com demência. Conclusão: O protocolo de avaliação deste ensaio clínico randomizado sobre os efeitos do programa iSupport-Brasil pode se tornar uma referência para os países que planejam adaptar e melhorar esta intervenção, usando soluções digitais de saúde.

ABSTRACT Objective: To obtain data on bed refusal in intensive care units in Brazil and to evaluate the use of triage systems by professionals. Methods: A cross-sectional survey. Using the Delphi methodology, a questionnaire was created contemplating the objectives of the study. Physicians and nurses enrolled in the research network of the Associação de Medicina Intensiva Brasileira (AMIBnet) were invited to participate. A web platform (SurveyMonkey®) was used to distribute the questionnaire. The variables in this study were measured in categories and expressed as proportions. The chi-square test or Fisher’s exact test was used to verify associations. The significance level was set at 5%. Results: In total, 231 professionals answered the questionnaire, representing all regions of the country. The national intensive care units had an occupancy rate of more than 90% always or frequently for 90.8% of the participants. Among the participants, 84.4% had already refused admitting patients to the intensive care unit due to the capacity of the unit. Half of the Brazilian institutions (49.7%) did not have triage protocols for admission to intensive beds. Conclusions: Bed refusal due to high occupancy rates is common in Brazilian intensive care units. Even so, half of the services in Brazil do not adopt protocols for triage of beds.

RESUMO Objetivo: Conhecer dados sobre recusa de leitos nas unidades intensivas no Brasil, assim como avaliar o uso de sistemas de triagem pelos profissionais atuantes. Métodos: Estudo transversal do tipo survey. Com a metodologia Delphi, foi criado um questionário contemplando os objetivos do trabalho. Foram convidados médicos e enfermeiros inscritos na rede de pesquisa da Associação de Medicina Intensiva Brasileira (AMIBnet). Uma plataforma da web (SurveyMonkey®) foi a forma de aplicação do questionário. As variáveis deste trabalho foram mensuradas em categorias e expressas como proporção. Foram usados o teste do qui-quadrado ou o teste exato de Fisher, para verificar associações. O nível de significância foi de 5%. Resultados: No total, 231 profissionais responderam o questionário, representando todas as regiões do país. As unidades intensivas nacionais tinham mais de 90% de taxa de ocupação sempre ou frequentemente para 90,8% dos participantes. Dentre os participantes, 84,4% já deixaram de admitir pacientes em leito intensivo devido à lotação da unidade. Metade das instituições brasileiras (49,7%) não possuía protocolos de triagem de leitos intensivos instituídos. Conclusão: A recusa de leito pela alta taxa de ocupação é frequente nas unidades de terapia intensiva do Brasil. Ainda assim, metade dos serviços do Brasil não adota protocolos para triagem de leitos.

Resumo O fenômeno de assistir lives musicais popularizou-se durante a pandemia do COVID-19, enquanto um ato de lazer dentro de casa. Durante três meses elas pertenceram à rotina de brasileiros e estrangeiros, para então perder audiência de forma exponencial. Essa trajetória é o objeto de pesquisa desse trabalho, estudada sob o prisma da teoria da prática, o qual buscou entender os elementos formadores dessa prática de consumo, sua sincronia com outras práticas do cotidiano, bem como fenômenos externos que atuam na consolidação (ou não) de uma prática. Para tal, foram coletadas entrevistas em profundidade com 24 praticantes, sendo os resultados analisados por meio de uma análise temática. Os achados dão pistas sobre os motivos pelos quais a prática decaiu, com destaque para a sobreposição de práticas pertencentes à rotina criada no isolamento social pelos praticantes, e redução da originalidade (entendimento) inicial de lives mais intimistas, que se perdem em meio à busca por inovações na prática. Possíveis desdobramentos sobre o futuro das lives pós pandemia, contribuições teóricas e gerenciais também são discutidos.

Abstract The phenomenon of watching live online music events became popular during the COVID-19 pandemic as a leisure activity practiced at home while social distancing. For 3 months, they were part of the routine of Brazilians and foreigners, before exponentially losing their audience. This trajectory is the object of research for this paper, studied under the prism of practice theory to understand the elements that form this consumption practice, its synchrony with other everyday practices, and external phenomena that act in the consolidation (or not) of a practice. In-depth interviews were conducted with 24 practitioners, and the results were analyzed through a thematic analysis. The findings provide clues as to why the practice declined, emphasizing the overlapping of practices belonging to the routine created during social distancing and the reduction of the initial originality (understanding) of more intimate lives that get lost in the search for innovations in practice. Possible developments in the future of post-pandemic live events and theoretical and managerial contributions are also discussed.

Resumen El fenómeno de ver lives musicales se hizo popular durante la pandemia de COVID-19, como un acto de ocio en casa. Durante tres meses pertenecieron a la rutina de brasileños y extranjeros, y luego perdieron su audiencia de manera exponencial. Esta trayectoria es el objeto de investigación de este trabajo, estudiada bajo el prisma de la teoría de la práctica, que buscó comprender los elementos que forman esta práctica de consumo, su sincronía con otras prácticas cotidianas, así como los fenómenos externos que actúan en la consolidación (o no) de una práctica. Para ello, se realizaron entrevistas en profundidad a 24 practicantes, y los resultados se analizaron mediante un análisis temático. Los hallazgos dan pistas sobre las razones por las que la práctica declinó, con énfasis en la superposición de prácticas pertenecientes a la rutina creada en el aislamiento social por los practicantes, y la reducción de la originalidad (opinión) inicial de lives más intimistas, que se pierden en medio de la búsqueda de innovaciones en la práctica. También se discuten los posibles desarrollos sobre el futuro de las lives pospandemia y las contribuciones teóricas y gerenciales.

ABSTRACT Camu-camu (Myrciaria dubia), a fruit from the Amazon region, has received attention due to its high content of antioxidant compounds such as ascorbic acid and polyphenols. This study's objective was to select camu-camu clones according to their morphological characteristic using multivariate analyses. We evaluated 56 camu-camu clones distributed in three blocks with two plants per experimental plot. The variables measured were plant height (H), number of basal branches (NBB), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b). Principal component (PCA) and multivariate clustering analyses were performed using the average linkage mean and Mahalanobis distance algorithms. After 24 months, results showed that the characteristic that least contributed to clone selection was NBB. The plant height (H), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b) had the most positive contribution towards the initial selection of camu-camu clones at two years of age. The 22 camu-camu clones showed the highest rate of vegetative development or vegetative quality index (VQI) in the transitional savanna/forest area of the northern Amazon, Brazil, after two years of transplanting.

RESUMEN El camu-camu (Myrciaria dubia) es una fruta de la región amazónica que ha recibido atención debido a su alto contenido de compuestos antioxidantes, como el ácido ascórbico y los polifenoles. El objetivo del estudio fue seleccionar clones de camu-camu según sus características morfológicas mediante análisis multivariados. Se evaluaron 56 clones de camu-camu distribuidos en tres bloques con dos plantas por parcela experimental. Las variables medidas fueron altura de la planta (H), número de ramas basales (NRB), número de brotes terminales (NBT), diámetro basal del tallo (DT), clorofila a (Chl a) y b (Chl b) y clorofila total (Chl a + b). Los análisis de agrupamiento de componentes principales (PCA) y multivariados se realizaron utilizando la media de enlace y los algoritmos de distancia de Mahalanobis. Después de 24 meses, los resultados mostraron que la característica que menos contribuyó a la selección del clon fue el NRB. La altura de la planta, número de ramas basales (NRB), diámetro basal del tallo (DBT), clorofila a (Chl a) y b (Chl b) y clorofila total (Chl a + b) tuvieron la contribución más positiva hacia la selección inicial de clones de camu-camu a los dos anos de edad. Veintidós clones de camu-camu presentaron la mayor tasa de desarrollo vegetativo o índice de calidad de la vegetación (ICV) en la sabana de transición/área forestal del norte del Amazonas, Brasil, después de dos anos de trasplante.

RESUMO A avaliação estrutural do cérebro, feita por meio dos exames de neuroimagem, é a forma mais utilizada de ferramenta diagnóstica e de acompanhamento das doenças neurodegenerativas. Técnicas de imagem mais sofisticadas podem ser necessárias especialmente nas fases mais precoces, antes mesmo do surgimento de quaisquer sintomas, porém costumam ser caras e pouco acessíveis. Sendo assim, é de fundamental importância a busca de biomarcadores não invasivos, de fácil acesso e baixo custo, que possam ser utilizados para rastreio populacional e diagnóstico mais precoce. Nesse cenário, o número de estudos com ênfase em técnicas de imagem para avaliação estrutural da retina em pacientes com doenças neurodegenerativas tem aumentado nos últimos anos. A retina apresenta similaridade embriológica, histológica, bioquímica, microvascular e neurotransmissora com o córtex cerebral, tornando-se assim um biomarcador único e promissor nas doenças neurodegenerativas. A tomografia de coerência óptica é uma moderna técnica de imagem não invasiva que gera imagens seccionais bidimensionais de alta resolução e medidas volumétricas tridimensionais reprodutivas do disco óptico e da mácula. Essa tecnologia é amplamente utilizada na prática oftalmológica para o diagnóstico e o seguimento de diversas doenças oculares, como glaucoma, retinopatia diabética e degeneração macular relacionada à idade. A redução da espessura da camada de fibras nervosas da retina e das camadas de células ganglionares em pacientes com doenças neurodegenerativas foi demonstrada em diversos estudos clínicos nos últimos anos. Nesta revisão, abordamos as principais aplicações clínicas da tomografia de coerência óptica nas doenças neurodegenerativas e discutimos o seu papel como potencial biomarcador nessas afecções.

ABSTRACT Structural imaging of the brain is the most widely used diagnostic tool for investigating neurodegenerative diseases. More advanced structural imaging techniques have been applied to early or prodromic phases, but they are expensive and not widely available. Therefore, it is highly desirable to search for noninvasive, easily accessible, low-cost clinical biomarkers suitable for large-scale population screening, in order to focus on making diagnoses at the earliest stages of the disease. In this scenario, imaging studies focusing on the structures of the retina have increasingly been used for evaluating neurodegenerative diseases. The retina shares embryological, histological, biochemical, microvascular and neurotransmitter similarities with the cerebral cortex, thus making it a uniquely promising biomarker for neurodegenerative diseases. Optical coherence tomography is a modern noninvasive imaging technique that provides high-resolution two-dimensional cross-sectional images and quantitative reproducible three-dimensional volumetric measurements of the optic nerve head and retina. This technology is widely used in ophthalmology practice for diagnosing and following up several eye diseases, such as glaucoma, diabetic retinopathy and age-related macular degeneration. Its clinical impact on neurodegenerative diseases has raised enormous interest over recent years, as several clinical studies have demonstrated that these diseases give rise to reduced thickness of the inner retinal nerve fiber layer, mainly composed of retinal ganglion cells and their axons. In this review, we aimed to address the clinical utility of optical coherence tomography for diagnosing and evaluating different neurodegenerative diseases, to show the potential of this noninvasive and easily accessible method.

RESUMO Objetivo: Identificar fatores que levam a uma resposta positiva da oxigenação e fatores preditivos de mortalidade após a pronação. Métodos: Estudo de coorte retrospectivo multicêntrico envolvendo sete hospitais brasileiros. Os critérios de inclusão foram idade > 18 anos com diagnóstico suspeito ou confirmado de COVID-19, ventilação mecânica invasiva, relação PaO2/FIO2 < 150 mmHg e pronação. Após a primeira sessão de pronação, uma melhora de 20 mmHg na relação PaO2/FIO2 foi definida como resposta positiva. Resultados: O estudo envolveu 574 pacientes, dos quais 412 (72%) apresentaram resposta positiva à primeira sessão de pronação. A regressão logística múltipla mostrou que os respondedores apresentaram menores pontuações no Simplified Acute Physiology Score III (SAPS III) e no SOFA e menores níveis de dímero D (p = 0,01; p = 0,04; e p = 0,04, respectivamente). Sugeriu-se que a pontuação no SAPS III e a PaO2/FIO2 iniciais seriam preditores da resposta da oxigenação. A taxa de mortalidade foi de 69,3%. Maior risco de mortalidade foi associado à idade (OR = 1,04 [IC95%: 1,01-1,06]), tempo até a primeira sessão de pronação (OR = 1,18 [IC95%: 1,06-1,31]), número de sessões (OR = 1,31 [IC95%: 1,00-1,72]), porcentagem de comprometimento pulmonar (OR = 1,55 [IC95%: 1,02-2,35]) e imunossupressão (OR = 3,83 [IC95%: 1,35-10,86]). Conclusões: Nossos resultados mostram que a maioria dos pacientes de nossa amostra apresentou resposta positiva da oxigenação após a primeira sessão de pronação. No entanto, a taxa de mortalidade foi elevada, provavelmente em virtude do estado de saúde e número de comorbidades dos pacientes e da gravidade de sua doença. Nossos resultados também sugerem que a pontuação no SAPS III e a PaO2/FIO2 inicial predizem a resposta da oxigenação; além disso, idade, tempo até a primeira sessão de pronação, número de sessões, comprometimento pulmonar e imunossupressão podem predizer mortalidade.

ABSTRACT Objective: To identify factors that lead to a positive oxygenation response and predictive factors of mortality after prone positioning. Methods: This was a retrospective, multicenter, cohort study involving seven hospitals in Brazil. Inclusion criteria were being > 18 years of age with a suspected or confirmed diagnosis of COVID-19, being on invasive mechanical ventilation, having a PaO2/FIO2 ratio < 150 mmHg, and being submitted to prone positioning. After the first prone positioning session, a 20 mmHg improvement in the PaO2/FIO2 ratio was defined as a positive response. Results: The study involved 574 patients, 412 (72%) of whom responded positively to the first prone positioning session. Multiple logistic regression showed that responders had lower Simplified Acute Physiology Score III (SAPS III)/SOFA scores and lower D-dimer levels (p = 0.01; p = 0.04; and p = 0.04, respectively). It was suggested that initial SAPS III and initial PaO2/FIO2 were predictors of oxygenation response. The mortality rate was 69.3%. Increased risk of mortality was associated with age (OR = 1.04 [95 CI: 1.01-1.06]), time to first prone positioning session (OR = 1.18 [95 CI: 1.06-1.31]), number of sessions (OR = 1.31 [95% CI: 1.00-1.72]), proportion of pulmonary impairment (OR = 1.55 [95% CI: 1.02-2.35]), and immunosuppression (OR = 3.83 [95% CI: 1.35-10.86]). Conclusions: Our results show that most patients in our sample had a positive oxygenation response after the first prone positioning session. However, the mortality rate was high, probably due to the health status and the number of comorbidities of the patients, as well as the severity of their disease. Our results also suggest that SAPS III and the initial PaO2/FIO2 predict the oxygenation response; in addition, age, time to first prone positioning, number of sessions, pulmonary impairment, and immunosuppression can predict mortality.