Neutralizing antibody titers against D8 genotype and persistence of measles humoral and cell-mediated immunity eight years after the first dose of measles, mumps, and rubella vaccine in Brazilian children.

OBJECTIVE: Assess the level of measles vaccine-induced neutralizing antibodies against the D8 genotype and the persistence of humoral and cell-mediated immunity in children who received their first dose of the measles, mumps, and rubella vaccine eight years previously. METHODS: Measles-specific IgG and neutralizing antibodies were determined in serum using ELISA and plaque reduction neutralization test, respectively. Cellular response was evaluated from peripheral blood mononuclear cells (PBMC). IFN-γ-secreting cells, memory B and T cells, and immunological mediators were assayed by ELISpot, flow cytometry, and multiplex liquid microarray assay, respectively. RESULTS: Antibody concentrations declined over time; however, the vaccine-induced neutralizing antibodies' effect against D8 and vaccinal genotypes persisted. PBMC stimulated with the vaccine virus exhibited specific IFN- γ-measles-secreting responses in most participants. Participants with high levels of neutralizing antibodies showed a higher proportion of activated B cells compared to participants with low levels of neutralizing antibodies, while proportions of memory CD4+ and CD8+ T cells were similar between these groups. PBMC supernatant cytokine levels showed a significant difference between stimulated and non-stimulated conditions for IL-2, TNF-α, IL-10, and CXCL10. CONCLUSION: Despite the decline in antibody concentrations over time, the participants still demonstrated neutralizing capacity against the measles D8 genotype five to eight years after the second dose of the measles, mumps, and rubella vaccine. Additionally, most of the enrolled children exhibited cell-mediated immunity responses to measles virus stimulation.

Plaque Reduction Neutralization Test (PRNT) Accuracy in Evaluating Humoral Immune Response to SARS-CoV-2.

Massive vaccination positively impacted the SARS-CoV-2 pandemic, being a strategy to increase the titers of neutralizing antibodies (NAbs) in the population. Assessing NAb levels and understanding the kinetics of NAb responses is critical for evaluating immune protection. In this study, we optimized and validated a PRNT50 assay to assess 50% virus neutralization and evaluated its accuracy to measure NAbs to the original strain or variant of SARS-CoV-2. The optimal settings were selected, such as the cell (2 × 105 cells/well) and CMC (1.5%) concentrations and the viral input (~60 PFU/well) for PRNT-SARS-CoV-2 with cut-off point = 1.64 log5 based on the ROC curve (AUC = 0.999). The validated PRNT-SARS-CoV-2 assay presented high accuracy with an intraassay precision of 100% for testing samples with different NAb levels (low, medium, and high titers). The method displays high selectivity without cross-reactivity with dengue (DENV), measles (MV), zika (ZIKV), and yellow fever (YFV) viruses. In addition, the standardized PRNT-SARS-CoV-2 assay presented robustness when submitted to controlled variations. The validated PRNT assay was employed to test over 1000 specimens from subjects with positive or negative diagnoses for SARS-CoV-2 infection. Patients with severe COVID-19 exhibited higher levels of NAbs than those presenting mild symptoms for both the Wuhan strain and Omicron. In conclusion, this study provides a detailed description of an optimized and validated PRNT50 assay to monitor immune protection and to subsidize surveillance policies applied to epidemiologic studies of COVID-19.

Differential gene expression of cytokines, receptors, and miRNAs in individuals living with HIV-1 and vaccinated against yellow fever.

Between 2016 and 2018, Brazil faced a yellow fever (YF) outbreak, which led to an expansion of vaccination coverage. The coexistence of the YF outbreak and the HIV-1 epidemic in Brazil raised concerns regarding the immune response and vaccine effectiveness in individuals living with HIV (PLWH). The aim of this study was to investigate the immune response to YF vaccination in PLWH and HIV-uninfected individuals as controls. Transcript levels of immunomodulatory molecules, including IL-6, IL-10, IL-21, TGF-ß, CD19, CD163, miR-21, miR-146, and miR-155, were measured using RTqPCR. TCD4+ cells were evaluated by cytometry, and neutralizing antibody (Nab) titers were detected by a micro plaque-reduction neutralization test. The findings of our study revealed several noteworthy observations. First, there was a notable reduction in the circulation of TCD4+ cells postvaccination. Among people living with HIV (PLWH), we observed an increase in the expression of IL-10 following vaccination, while IL-6 expression was diminished in PLWH with lower TCD4+ counts. Furthermore, we identified the downregulation of CD19 and TGF-ß, along with the upregulation of IL-21 and CD163. Notably, we observed positive correlations between the levels of IL-10/IL-21, IL-10/CD163, and IL-6/CD19. Additionally, there was a positive correlation between miRNAs 146 and 155. It is important to emphasize that all participants exhibited robust neutralizing antibody responses after receiving 17DD YF vaccination. In this context, the gene expression data presented can be useful for biomarker studies of protective antibodies induced by YF vaccination. This study sheds light on immune mechanisms in individuals living with HIV and YF vaccination.

Inhibition of SARS-CoV-2 Infection in Vero Cells by Bovine Lactoferrin under Different Iron-Saturation States.

Despite the rapid mass vaccination against COVID-19, the emergence of new SARS-CoV-2 variants of concern, such as omicron, is still a great distress, and new therapeutic options are needed. Bovine lactoferrin (bLf), a multifunctional iron-binding glycoprotein available in unsaturated (apo-bLf) and saturated (holo-bLf) forms, has been shown to exert broad-spectrum antiviral activity against many viruses. In this study, we evaluated the efficacy of both forms of bLf at 1 mg/mL against infection of Vero cells by SARS-CoV-2. As assessed with antiviral assays, an equivalent significant reduction in virus infection by about 70% was observed when either form of bLf was present throughout the infection procedure with the SARS-CoV-2 ancestral or omicron strain. This inhibitory effect seemed to be concentrated during the early steps of virus infection, since a significant reduction in its efficiency by about 60% was observed when apo- or holo-bLf were incubated with the cells before or during virus addition, with no significant difference between the antiviral effects of the distinct iron-saturation states of the protein. However, an ultrastructural analysis of bLf treatment during the early steps of virus infection revealed that holo-bLf was somewhat more effective than apo-bLf in inhibiting virus entry. Together, these data suggest that bLf mainly acts in the early events of SARS-CoV-2 infection and is effective against the ancestral virus as well as its omicron variant. Considering that there are no effective treatments to COVID-19 with tolerable toxicity yet, bLf shows up as a promising candidate.

Inactivated and Immunogenic SARS-CoV-2 for Safe Use in Immunoassays and as an Immunization Control for Non-Clinical Trials.

Successful SARS-CoV-2 inactivation allows its safe use in Biosafety Level 2 facilities, and the use of the whole viral particle helps in the development of analytical methods and a more reliable immune response, contributing to the development and improvement of in vitro and in vivo assays. In order to obtain a functional product, we evaluated several inactivation protocols and observed that 0.03% beta-propiolactone for 24 h was the best condition tested, as it promoted SARS-CoV-2 inactivation above 99.99% and no cytopathic effect was visualized after five serial passages. Moreover, RT-qPCR and transmission electron microscopy revealed that RNA quantification and viral structure integrity were preserved. The antigenicity of inactivated SARS-CoV-2 was confirmed by ELISA using different Spike-neutralizing monoclonal antibodies. K18-hACE2 mice immunized with inactivated SARS-CoV-2, formulated in AddaS03TM, presented high neutralizing antibody titers, no significant weight loss, and longer survival than controls from a lethal challenge, despite RNA detection in the oropharyngeal swab, lung, and brain. This work emphasizes the importance of using different techniques to confirm viral inactivation and avoid potentially disastrous contamination. We believe that an efficiently inactivated product can be used in several applications, including the development and improvement of molecular diagnostic kits, as an antigen for antibody production as well as a control for non-clinical trials.

Protective Immunity of COVID-19 Vaccination with ChAdOx1 nCoV-19 Following Previous SARS-CoV-2 Infection: A Humoral and Cellular Investigation.

Infections caused by SARS-CoV-2 induce a severe acute respiratory syndrome called COVID-19 and have led to more than six million deaths worldwide. Vaccination is the most effective preventative measure, and cellular and humoral immunity is crucial to developing individual protection. Here, we aim to investigate hybrid immunity against SARS-CoV-2 triggered by the ChAadOx1 nCoV-19 vaccine in a Brazilian cohort. We investigated the immune response from ChAadOx1 nCoV-19 vaccination in naïve (noCOVID-19) and previously infected individuals (COVID-19) by analyzing levels of D-dimers, total IgG, neutralizing antibodies (Nabs), IFN-γ (interferon-γ) secretion, and immunophenotyping of memory lymphocytes. No significant differences in D-dimer levels were observed 7 or 15 days after vaccination (DAV). All vaccinated individuals presented higher levels of total IgG or Nabs with a positive correlation (R = 0.88). Individuals in the COVID-19 group showed higher levels of antibody and memory B cells, with a faster antibody response starting at 7 DAV compared to noCOVID-19 at 15 DAV. Further, ChAadOx1 nCoV-19 vaccination led to enhanced IFN-γ production (15 DAV) and an increase in activated T CD4+ naïve cells in noCOVID-19 individuals in contrast with COVID-19 individuals. Hence, our data support that hybrid immunity triggered by ChAadOx1 nCoV-19 vaccination is associated with enhanced humoral response, together with a balanced cellular response.

Condiloma acuminado na infância tratado com creme de imiquimode a 5%: relato de caso / Condylomata acuminata in childhood treated with 5% imiquimod cream: case report

O condiloma acuminado é causado pelo DNA-vírus, que pertence ao grupo papovavírus. Em menores de três anos, a transmissão tende a não ser por abuso sexual, mas, sim, de maneira vertical. Não existe consenso para o tratamento das verrugas anogenitais em crianças. O método escolhido é individualizado para o paciente, sendo a preferência por tratamentos menos traumáticos, com menor sequela. Embora ainda existam algumas restrições ao uso do imiquimode em menores de 12 anos, estudos já mostram o sucesso desta terapêutica nesta faixa etária. Será descrito um caso tratado com imiquimode creme a 5%, com resolução das lesões preexistentes

DNA-virus, which belongs to the papillomavirus group, causes Condylomata acuminata. In children under 3 years of age, transmission tends not to be due to sexual abuse but rather vertically. There is no consensus for the treatment of anogenital warts in children. The chosen method is individualized for each patient, preferring less traumatic treatments, with fewer sequelae. Although there are still some restrictions on the imiquimod use in children under 12, studies have already shown this therapy's success in this age group. We report a case treated with 5% imiquimod cream with the resolution of pre-existing lesions.

Análise crítica da técnica de imunofluorescência direta no diagnóstico laboratorial da raiva do Instituto Pasteur de São Paulo

Embora a Organização Mundial da Saúde preconize a técnica de Imunofluorescência Direta (IFD) como padrão ouro para o diagnóstico laboratorial da raiva, fatores externos podem influenciar o limiar de detecção do antígeno viral, como a conservação da amostra, a estrutura laboratorial, os insumos utilizados e o treinamento dos profissionais. O objetivo deste estudo foi analisar criticamente a técnica de IFD no Laboratório de Diagnóstico da Raiva do Instituto Pasteur, a fim de detectar eventuais fatores externos que possam limitar ou diminuir sua acurácia, visto que o resultado laboratorial tem papel determinante na tomada de decisão quanto ao tratamento de indivíduos expostos ao risco de infecção pelo vírus da raiva. Foram analisados os dados todas as amostras de sistema nervoso central (SNC) de animais suspeitos de infecção pelo vírus da raiva, recebidas durante o ano de 2019, além de uma avaliação prática de 300 amostras dos procedimentos laboratoriais relacionados à IFD no qual avaliou-se a fixação do tecido, bem como os diluentes controles para o uso do conjugado. Pode-se inferir que a fixação das lâminas sob ambas condições (temperatura ambiente e a -20ºC) demonstrou equivalência em relação à qualidade do tecido analisado. Todos os sistemas utilizados para diluição do conjugado apresentaram eficácia ficando evidente a viabilidade da substituição de suspensão de CVS produzido in vivo para in vitro. Ao analisar os resultados da IFD negativos, houve concordância de 99,9% com as demais técnicas aplicadas. A sensibilidade e especificidade da técnica de IFD foram avaliadas em relação aos resultados obtidos dentre todas as demais metodologias complementares conjuntamente, com sensibilidade de 94,3%, especificidade de 99,9% e acurácia de 99,8%. Em relação a intensidade de fluorescência de fragmentos de SNC de herbívoros positivos avaliados, observou-se que fragmentos de cerebelo e tronco encefálico apresentaram um ligeiro aumento na intensidade das células infectadas em relação ao hipocampo e córtex cerebral (AU).

Pesquisa translacional e sistemas de inovação na saúde: implicações para o segmento biofarmacêutico / Translational research and innovation systems in health: implications on the biopharmaceutical segment

RESUMO A análise desenvolvida sobre a dinâmica de inovação em saúde no contexto do Sistema Nacional de Inovação em Saúde revela as potencialidades da articulação das instituições de Ciência, Tecnologia e Inovação (CT&I) com o Complexo Econômico-Industrial da Saúde (Ceis), a partir da interação entre as universidades e os institutos de pesquisa com o setor produtivo. A translação em saúde depende fortemente da dinâmica e da situação relativa do Ceis no Brasil ante o contexto internacional. O estudo faz uma análise das interações entre empresas farmacêuticas e grupos de pesquisa em saúde no País dos microdados da base de dados do Diretório de Grupos de Pesquisa do Conselho Nacional de Desenvolvimento Científico e Tecnológico (DGP-CNPq), utilizando uma abordagem metodológica apropriada aos estudos de redes de colaboração. Ademais, mostra o potencial de diversas instituições de CT&I brasileiras, revelando a presença de uma rede de interações com o setor produtivo na área biofarmacêutica, com potencial para o desenvolvimento do sistema de inovação em saúde. Essa interação poderá adquirir, de fato, uma perspectiva translacional para a utilização do conhecimento tecnológico pela sociedade brasileira na medida em que seja articulada com o desenvolvimento do Ceis no Brasil, como elo crítico no qual a pesquisa se transforma em produção de bens e serviços para atender às demandas do Sistema Único de Saúde.

ABSTRACT The analysis of the dynamics of innovation in health in the context of the National System of Innovation in Health reveals the potential of the articulation of Science, Technology and Innovation (ST&I) institutions with the Health Economic-Industrial Complex (HEIC), in view of the interactions between universities and research institutes with the productive sector. Translational health research depends heavily on the dynamics and relative situation of the HEIC in Brazil regarding the international context. The study analyzes the interactions between pharmaceutical companies and health research groups in the country, using microdata from the CNPq Research Group Directory database (DGP-CNPq), in a methodological approach appropriate to collaborative network studies. Furthermore, it shows the presence of a network of interactions with the productive sector in the biopharmaceutical area and highlights the potential of several Brazilian ST&I institutions to foster the development of the health innovation system. This interaction may acquire a translational perspective for the use of technological knowledge by the Brazilian society insofar as it is articulated with the development of the HEIC in Brazil as a critical link to meet the demands of the Unified Health System.

Avaliação da conduta dos consumidores em relação às Boas Práticas de higiene em restaurantes self-service situados no município de Valença, RJ / Evaluation of consumer conduct on good hygienic practices in self-service restaurants located in the municipality of Valença, RJ

A fim de oferecer uma refeição de qualidade, os serviços de alimentação (SA) devem, além de atender as normas das Boas Práticas de Fabricação, alertar consumidores sobre condutas higiênicas no ato de montagem dos pratos. Objetivou-se avaliar a conduta de Boas Práticas de higiene de consumidores que frequentam SA do tipo self-service. Foram avaliadas atitudes consideradas de risco de contaminação durante o ato de montagem dos pratos. Quase ¾ dos consumidores não higienizaram as mãos antes de se servirem e mais de » trocaram os utensílios entre as preparações. Os resultados apontaram comportamentos que podem comprometer a segurança das refeições oferecidas. Conclui-se que a conduta higiênico-sanitária dos consumidores no ato de se servir deve ser melhorada, para isso, ações educativas e ilustrativas in loco devem ser adotadas.

Impacto de ações de capacitação em Boas Práticas de Fabricação na condição higiênico-sanitária de restaurantes self-service do município de Valença-RJ / Evaluation of hygienicosanitary quality control in food and training services in good manufacturing practices for food manipulators in the municipality of Valença, RJ

Considerando que os serviços de alimentação (SA) estão entre os principais estabelecimentos envolvidos nos surtos de doenças transmitidas por alimentos, objetivou-se avaliar o impacto da capacitação em Boas Práticas de Fabricação nas condições higiênico-sanitárias (CHS) de três restaurantes self-service (R1, R2 e R3). A avaliação ocorreu antes e após o treinamento através da aplicação do check list da RDC 275/2002 com adaptações da RDC 216/2004 e a classificação de acordo com o percentual de conformidade em grupos, tais como G1 (76 a 100%), G2 (51 a 75%) e G3 (0 a 50%). Os resultados apontaram evolução em R1 de G2 para G1 e nos demais de G3 para G2. Conclui-se que o processo de capacitação contribuiu com a melhoria global das CHS, indicando a necessidade de implantação de um programa de treinamentos constante para estes estabelecimentos.

Stability of different influenza subtypes: How can high hydrostatic pressure be a useful tool for vaccine development?

BACKGROUND: Avian influenza A viruses can cross naturally into mammals and cause severe diseases, as observed for H5N1. The high lethality of human infections causes major concerns about the real risk of a possible pandemic of severe diseases to which human susceptibility may be high and universal. High hydrostatic pressure (HHP) is a valuable tool for studies regarding the folding of proteins and the assembly of macromolecular structures such as viruses; furthermore, HHP has already been demonstrated to promote viral inactivation. METHODS: Here, we investigated the structural stability of avian and human influenza viruses using spectroscopic and light-scattering techniques. We found that both particles have similar structural stabilities and that HHP promotes structural changes. RESULTS: HHP induced slight structural changes to both human and avian influenza viruses, and these changes were largely reversible when the pressure returned to its initial level. The spectroscopic data showed that H3N2 was more pressure-sensitive than H3N8. Structural changes did not predict changes in protein function, as H3N2 fusion activity was not affected, while H3N8 fusion activity drastically decreased. The fusion activity of H1N1 was also strongly affected by HHP. In all cases, HHP caused inactivation of the different influenza viruses. CONCLUSIONS: HHP may be a useful tool for vaccine development, as it induces minor and reversible structural changes that may be associated with partial preservation of viral biological activities and may potentiate their immunogenic response while abolishing their infectivity. We also confirmed that, although pressure does not promote drastic changes in viral particle structure, it can distinctly affect viral fusion activity.

Vulvar width and rima length as predictors of the ovarian follicular reserve in bovine females.

The aim of this study was to investigate possible relationships between morphometric characteristics of the bovine reproductive tract and measures of fertility, such as antral follicle counts (AFCs) and the number and quality of recovered cumulus oophorus complexes (COCs). First, the genital tracts of 360 abattoir Zebu/Holstein crossbred cows were studied. Rima vulvae length (RL), vulvar width (VW), ovarian size, pelvic fat, number of aspirated COCs, and AFCs were recorded. An index of COC quality (CQI) was established, which weighed overall gamete quality based on the IETS classification. Second, the same external measurements and AFCs (by ultrasound) were analyzed in live Tabapuã (Zebu) cows (n = 48). Relative RL and vulvar width were defined as the original measurements divided by the body weight of each cow for statistical analyses. In abattoir tracts, the AFC was smaller (P < 0.05) in animals with large VW (34.88 ± 3.50) than in animals with small (45.71 ± 2.57) and intermediate (42.25 ± 2.45) VW. The CQI was higher (P < 0.05) when the pelvic fat score was intermediate (3.22 ± 0.06) than that in lean (2.99 ± 0.08) and obese (2.90 ± 0.12) animals. The CQI was higher (P < 0.05) in the intermediate ovary group (3.19 ± 0.08) than in the small (2.96 ± 0.08) and large (2.95 ± 0.09) ovary groups. In live cows, the AFC was higher (P = 0.035) in females with large relative rima length than in those with small relative rima length (18.96 ± 1.97 and 14.76 ± 1.51, respectively). Similarly, AFC was greater (P = 0.0001) in females with large relative VW than in those with small relative VW (20.08 ± 1.36 and 11.16 ± 1.60, respectively). In conclusion, larger external genitalia relative to body size were good predictors of the ovarian follicular reserve in live animals.

Dental age estimation in a Brazilian adult population using Cameriere's method.

The objectives of this study were to develop a specific formula to estimate age in a Brazilian adult population and to compare the original formula from Cameriere to this Brazilian formula. The sample comprised 1,772 periapical radiographs from 443 subjects (219 men, 224 women) that were organized into 12 groups according to sex (men or women) and age (20-29, 30-39, 40-49, 50-59, 60-69, and 70 years and older). The films were analyzed using the criteria described by Cameriere et al. (2004) and Adobe Photoshop®. We obtained a mean error of 8.56 (SD = 5.80) years for tooth 13, 7.99 (SD = 5.78) years for tooth 23, 8.38 (SD = 6.26) years for tooth 33, and 8.20 (SD = 6.54) years for tooth 43. When teeth were combined in the analysis, we observed lower mean errors. The Brazilian formula developed from this sample group was more accurate than Cameriere's formula. However, other factors must be considered to improve age estimates in adults.

Dental age estimation in a Brazilian adult population using Cameriere’s method

The objectives of this study were to develop a specific formula to estimate age in a Brazilian adult population and to compare the original formula from Cameriere to this Brazilian formula. The sample comprised 1,772 periapical radiographs from 443 subjects (219 men, 224 women) that were organized into 12 groups according to sex (men or women) and age (20-29, 30-39, 40-49, 50-59, 60-69, and 70 years and older). The films were analyzed using the criteria described by Cameriere et al. (2004) and Adobe Photoshop®. We obtained a mean error of 8.56 (SD = 5.80) years for tooth 13, 7.99 (SD = 5.78) years for tooth 23, 8.38 (SD = 6.26) years for tooth 33, and 8.20 (SD = 6.54) years for tooth 43. When teeth were combined in the analysis, we observed lower mean errors. The Brazilian formula developed from this sample group was more accurate than Cameriere’s formula. However, other factors must be considered to improve age estimates in adults.

Prevalence of Chagas disease in blood donors at the Uberaba Regional Blood Center, Brazil, from 1995 to 2009 / Prevalência da doença de Chagas em doadores de sangue do Hemocentro Regional de Uberaba, Brasil, entre 1995 e 2009

INTRODUCTION: A retrospective study was conducted to assess the occurrence of blood donations that were ineligible due to Chagas disease infection from 1995 to 2009 at the Uberaba Regional Blood Center (HRU), Brazil, verify the tendency of this ineligibility, and describe the epidemiologic profile of the donors. METHODS: Retrospective studies of serological ineligibility due to Chagas disease, statistical analysis by means of the chi-square test and odds ratio, study of the tendencies using a dispersion graph and the linear correlation coefficient (r) were performed. RESULTS: In the period under study, a 0.2% serum prevalence of ineligibility due to Chagas disease was found, with a significant drop in ineligible donations from 2001 to 2009. Among the serum positive-donors, there was a significant predominance among those aged 30 years or above and non-single individuals. CONCLUSIONS: The results show a rate of occurrence that is lower than that described in literature, as well as a progressive drop during the 15 years under assessment. Such results are a consequence of systematic combat of the vector since the 70s and the progressive and consistent increase of returning donors, resulting in a drop of the contamination risk factor by means of blood transfusion and in the improvement of the quality of hemotherapy practices in the HRU.

INTRODUÇÃO: Estudo retrospectivo com o objetivo de avaliar a ocorrência de doações inaptas para doença de Chagas entre 1995 e 2009 no Hemocentro Regional de Uberaba (HRU), Brasil; verificar a tendência dessa inaptidão e descrever o perfil epidemiológico dos doadores. MÉTODOS: Estudo retrospectivo da inaptidão sorológica para doença de Chagas; análise estatística pelo teste do qui quadrado e odds ratio; estudo de tendência a partir do gráfico de dispersão e do coeficiente de correlação linear (r). RESULTADOS: No período em estudo foi encontrada uma soroprevalência de inaptidão para doença de Chagas de 0.2% com queda significativa de doações inaptas de 2001 a 2009. Dentre os soropositivos, observou-se predomínio significante na idade superior ou igual a 30 anos, e estado civil casado e outros. CONCLUSÕES: Os resultados demonstram taxa de ocorrência menor que as descritas na literatura, além de queda progressiva no decorrer dos 15 anos avaliados. Tais resultados são consequência do combate sistemático ao vetor a partir dos anos 70 e do progressivo e consistente aumento de doadores de retorno, resultando em queda do risco de contaminação via transfusão de sangue e na melhora da qualidade da hemoterapia praticada no HRU.

The structural dynamics of the flavivirus fusion peptide-membrane interaction.

Membrane fusion is a crucial step in flavivirus infections and a potential target for antiviral strategies. Lipids and proteins play cooperative roles in the fusion process, which is triggered by the acidic pH inside the endosome. This acidic environment induces many changes in glycoprotein conformation and allows the action of a highly conserved hydrophobic sequence, the fusion peptide (FP). Despite the large volume of information available on the virus-triggered fusion process, little is known regarding the mechanisms behind flavivirus-cell membrane fusion. Here, we evaluated the contribution of a natural single amino acid difference on two flavivirus FPs, FLA(G) ((98)DRGWGNGCGLFGK(110)) and FLA(H) ((98)DRGWGNHCGLFGK(110)), and investigated the role of the charge of the target membrane on the fusion process. We used an in silico approach to simulate the interaction of the FPs with a lipid bilayer in a complementary way and used spectroscopic approaches to collect conformation information. We found that both peptides interact with neutral and anionic micelles, and molecular dynamics (MD) simulations showed the interaction of the FPs with the lipid bilayer. The participation of the indole ring of Trp appeared to be important for the anchoring of both peptides in the membrane model, as indicated by MD simulations and spectroscopic analyses. Mild differences between FLA(G) and FLA(H) were observed according to the pH and the charge of the target membrane model. The MD simulations of the membrane showed that both peptides adopted a bend structure, and an interaction between the aromatic residues was strongly suggested, which was also observed by circular dichroism in the presence of micelles. As the FPs of viral fusion proteins play a key role in the mechanism of viral fusion, understanding the interactions between peptides and membranes is crucial for medical science and biology and may contribute to the design of new antiviral drugs.

Ocorrência da sorologia positiva para hepatite B nos doadores de sangue do Hemocentro Regional de Uberaba (MG) no período de 1995 a 2009 / Occurrence of positive serology for hepatitis B among blood donors at a blood bank in the city of Uberaba (MG), Brazil, between 1995 and 2009

Introdução: As infecções pelo vírus da hepatite B (HBV) constituem grave problema de saúde pública. A transmissão por via transfusional é uma das principais formas de contágio do vírus. Objetivos: Calcular a prevalência de doadores soropositivos, no período de 1995 a 2008, analisando-os quanto ao perfil epidemiológico, tendência e presença dos marcadores HBsAg eAnti-HBc. Métodos: Estudo retrospectivo dos doadores inaptos (ELISA), no Hemocentro Regional de Uberaba (HRU), através de teste qui quadrado e cálculo de odds ratio; análise de associação a partir do gráfico de dispersão e do coeficiente de correlação linear (r), com nível de significânciade 5por cento. Resultados: No período de 1995 a 2008, o HRU contou com 60811 doadores de sangue, sendo a prevalência de inaptos 5,6por cento; respectivamente: HBsAg positivo/Anti-HBc- 0,2por cento (120 doadores); HBsAg-/Anti-HBc positivo 5,24por cento (3192) e HBsAg positivo/Anti-HBc positivo 0,16por cento (101). Em relação ao perfilepidemiológico, observou-se predomínio significativo do gênero masculino; faixa etária maior ou igual a 30 anos; estado civil casados e outros quando comparados com os solteiros; não caucasóides e procedentes de Uberaba. Conclusão: Observa-se tendência decrescente de inaptidão no períodoestudado.

Prevalence of Chagas disease in blood donors at the Uberaba Regional Blood Center, Brazil, from 1995 to 2009.

INTRODUCTION: A retrospective study was conducted to assess the occurrence of blood donations that were ineligible due to Chagas disease infection from 1995 to 2009 at the Uberaba Regional Blood Center (HRU), Brazil, verify the tendency of this ineligibility, and describe the epidemiologic profile of the donors. METHODS: Retrospective studies of serological ineligibility due to Chagas disease, statistical analysis by means of the chi-square test and odds ratio, study of the tendencies using a dispersion graph and the linear correlation coefficient (r) were performed. RESULTS: In the period under study, a 0.2% serum prevalence of ineligibility due to Chagas disease was found, with a significant drop in ineligible donations from 2001 to 2009. Among the serum positive-donors, there was a significant predominance among those aged 30 years or above and non-single individuals. CONCLUSIONS: The results show a rate of occurrence that is lower than that described in literature, as well as a progressive drop during the 15 years under assessment. Such results are a consequence of systematic combat of the vector since the 70s and the progressive and consistent increase of returning donors, resulting in a drop of the contamination risk factor by means of blood transfusion and in the improvement of the quality of hemotherapy practices in the HRU.