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Background: The city of Manaus, Brazil, has seen two collapses of the health system due to the COVID-19 pandemic. We report anti-SARS-CoV-2 nucleocapsid IgG antibody seroconversion rates and associated risk factors in Manaus residents before the second wave of the epidemic in Brazil. Methods: A convenience sample of adult (aged ≥18 years) residents of Manaus was recruited through online and university website advertising into the DETECTCoV-19 study cohort. The current analysis of seroconversion included a subgroup of DETECTCoV-19 participants who had at least two serum sample collections separated by at least 4 weeks between Aug 19 and Oct 2, 2020 (visit 1), and Oct 19 and Nov 27, 2020 (visit 2). Those who reported (or had no data on) having a COVID-19 diagnosis before visit 1, and who were positive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at visit 1 were excluded. Using an in-house ELISA, the reactivity index (RI; calculated as the optical density ratio of the sample to the negative control) for serum anti-SARS-CoV-2 nucleocapsid IgG antibodies was measured at both visits. We calculated the incidence of seroconversion (defined as RI values ≤1·5 at visit 1 and ≥1·5 at visit 2, and a ratio >2 between the visit 2 and visit 1 RI values) during the study period, as well as incidence rate ratios (IRRs) through cluster-corrected and adjusted Poisson regression models to analyse associations between seroconversion and variables related to sociodemographic characteristics, health access, comorbidities, COVID-19 exposure, protective behaviours, and symptoms. Findings: 2496 DETECTCoV-19 cohort participants returned for a follow-up visit between Oct 19 and Nov 27, 2020, of whom 204 reported having COVID-19 before the first visit and 24 had no data regarding previous disease status. 559 participants were seropositive for anti-SARS-CoV-2 nucleocapsid IgG antibodies at baseline. Of the remaining 1709 participants who were seronegative at baseline, 71 did not meet the criteria for seroconversion and were excluded from the analyses. Among the remaining 1638 participants who were seronegative at baseline, 214 showed seroconversion at visit 2. The seroconversion incidence was 13·06% (95% CI 11·52–14·79) overall and 6·78% (5·61–8·10) for symptomatic seroconversion, over a median follow-up period of 57 days (IQR 54–61). 48·1% of seroconversion events were estimated to be asymptomatic. The sample had higher proportions of affluent and higher-educated people than those reported for the Manaus city population. In the fully adjusted and corrected model, risk factors for seroconversion before visit 2 were having a COVID-19 case in the household (IRR 1·49 [95% CI 1·21–1·83]), not wearing a mask during contact with a person with COVID-19 (1·25 [1·09–1·45]), relaxation of physical distancing (1·31 [1·05–1·64]), and having flu-like symptoms (1·79 [1·23–2·59]) or a COVID-19 diagnosis (3·57 [2·27–5·63]) between the first and second visits, whereas working remotely was associated with lower incidence (0·74 [0·56–0·97]). Interpretation: An intense infection transmission period preceded the second wave of COVID-19 in Manaus. Several modifiable behaviours increased the risk of seroconversion, including non-compliance with non-pharmaceutical interventions measures such as not wearing a mask during contact, relaxation of protective measures, and non-remote working. Increased testing in high-transmission areas is needed to provide timely information about ongoing transmission and aid appropriate implementation of transmission mitigation measures. Funding: Ministry of Education, Brazil; Fundação de Amparo à Pesquisa do Estado do Amazonas; Pan American Health Organization (PAHO)/WHO. World Health Organization Revisión por pares

Background: Twice city of Manaus located in the Brazilian rainforest, has experienced a health system collapse due to the SARS-CoV-2 pandemic. However, little is known about which groups among the general population have been more affected. In this report, we present the overall prevalence of SARS-CoV-2 infection and associated factors from the DETECTCoV-19 cohort. Methods: A convenience sampling strategy via online advertising recruited 3046 adults. Sociodemographic characteristics, COVID-19-related symptoms, COVID-19 testing, self-medication and prescribed medications were recorded. Serum anti-SARS-CoV-2 nucleocapsid IgG antibodies were measured with an in-house ELISA. Prevalence ratios (PR) were obtained using cluster-corrected and adjusted Poisson’s regression models. Findings: A crude positivity rate among asymptomatic and symptomatic individuals, was estimated at 29·10%, with a maximum seroprevalence of 41·53% corrected by test characteristics and an antibody decay rate of 27%. Regression models demonstrated a strong association towards marginalized low-income and vulnerable residents with limited health access. Presence of a COVID-19 case (PR 1·39, 1·24-1·57) or death (PR 2·14, 1·74-2·62) in a household increased greatly the risk of other household members acquiring infection. SARS-CoV-2 seroprevalence was higher among those who self-medicated to prevent infection (PR 1·36, 1·27-1·46). Interpretation: High SARS-CoV-2 seropositivity reveals a much burdensome scenario than estimations based on confirmed COVID-19 cases in Manaus. Overall, prevalence of SARS-CoV-2 antibody response demonstrated a disproportionate social and economic disparity among the study participants. The syndemic nature of COVID-19 in the Amazon region needs differential policies and urgent solutions to control the pandemic. Funding: Research was funded by Ministry of Education (MEC), Brazil. BBS, IVPF, ROS, ARCB and WBSS received scholarship from CAPES. DSSS, TBNM, MFF and NOC received scholarship from FAPEAM Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: The research ethics committee of Federal University of Amazonas (UFAM) approved this study (CAAE:34906920·4·0000·5020) in accordance with Brazilian law

Made available in DSpace on 2016-09-23T15:48:02Z (GMT). No. of bitstreams: 1 Relatório_IVANILDO_Final.pdf: 732151 bytes, checksum: ceba80b0b4f74c877882c9d474ea3869 (MD5) Previous issue date: 2015-07-31 CNPQ Oriunda da família Lecythidaceae, a Castanheira-do-Brasil, Bertholletia excelsa,é uma árvore muito comum, porém distribuída desigualmente pelo ecossistema amazônico. Possui grande importância econômica devido aos frutos serem a principal fonte de renda dos povos ribeirinhos da região em tempos chuvosos. Alguns estudos demonstram que a Castanheira-do-Brasil possui compostos fenólicos e selênio, muito úteis no combate ao estresse oxidativo, visto que tais substâncias atuam reduzindo e captando radicais livres, podendo ser utilizadas como importantes antioxidantes naturais. Somando-se a isso, o Selênio também é um importante composto que atua na redução da atividade de inflamação. Evidenciam preliminares tem sugerido um alto potencial antioxidante de um extrato das cascas da castanheira. Neste sentido, o presente estudo destina-se a avaliar as propriedades antioxidantes e anti-inflamatórias de um extrato hidroetanólico do do caule de Bertholletia excelsa, por meio de testes laboratoriais in vitro. Serão investigados os potenciais antioxidantes por meio dos testes de DPPH, teor de fenóis totaise flavonoides alem do estudo da atividade antioxidante em células e do efeito imunomodulador em macrófagos ativados por lipopolissacarídeo (LPS). Estes trabalho visa identificar o potencial antioxidante e antiinflamatorio das cascas de Bertholletia excelsa.

Made available in DSpace on 2016-09-23T15:48:02Z (GMT). No. of bitstreams: 1 Relatorio_FINAL_do_PIBIC__ERICO.pdf: 875473 bytes, checksum: 3465185cdb09ec95cc2397161303b2b4 (MD5) Previous issue date: 2015-07-31 CNPQ O estresse oxidativo é causado pelo excesso de radicais livres, que acabam promovendo dano celular e tecidual. Os radicais livres são produtos do metabolismo celular, entretanto podem ter sua formação intensificada por meio de estímulos exógenos (radiação, toxinas, drogas, produtos químicos, poluentes ambientais), constantemente presente em diversas patologias. A ativação de diversas enzimas na resposta de defesa à agressão oxidativa faz com que a célula intensifique a expressão gênica dessas proteínas, como a superoxido dismutase (SOD), Catalase (CAT) e peroxidades (GPx) e glutationa redutase (GSH-red), entre outras. Outra maneira de intensificar uma resposta defensiva, porém não enzimática, é por meio de substancias com propriedades antioxidantes, para evitar a formação desses radicais livres. São elas vitaminas (A e E, pró-beta-carotenos) e outros compostos, como os compostos fenólicos. Os compostos fenólicos tem a capacidade de captar radicais livres, diminuindo a sua disponibilidade e consequentemente reduzir o dano celular/tecidual. Estudos previamente realizados revelaram que o extrato da casca do caule de Bertholletia excelsa apresentou uma quantidade relevante de compostos fenólicos. Este trabalho tem como objetivo verificar a regulação gênica das defesas antioxidantes in vitro em fibroblastos sob estresse oxidativo, avaliando os genes evidenciados tanto em células sob estresse, quanto em células expostas ao extrato de Bertholletia excelsa para verificar os genes evidenciados em resposta ao tratamento. As culturas de células serão expostas a um agente oxidante, como o peróxido de hidrogênio (H2O2), o que induzirá a célula a responder contra o estresse oxidativo, portanto promovendo a maior expressão gênica dessas proteínas de defesa. Neste caso avalia-se-á qual a resposta que a célula apresentará sob estresse e qual o efeito do tratamento da célula com o extrato de Bertholletia excelsa sobre esta resposta. Após o tratamanto das células será conduzida a extração do RNA dessas células e utilização da técnica de PCR (Polymerase Chain Reaction),para analises dos genes NRf2, GPx e SOD. Espera-se identificar de que forma o extrato regula a resposta antioxidante nesta célula, o que servira como base para estudos futuros nesta área.