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Barros AJD, Victora CG, Menezes AMB, Horta BL, Barros FC, Hartwig FP, Victora GD, Vidaletti LP, Silveira MF, Mesenburg MA, Jacques N, Struchiner CJ, Brust FR, Dall'Agnol MM, Delamare APL, François CHR, Ikeda MLR, Pellegrini DCP, Reuter CP, Silva SGD, Dellagostin OA, Hallal PC. Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil. Rev Saude Publica 2021; 55:78. [PMID: 34816981 PMCID: PMC8577540 DOI: 10.11606/s1518-8787.2021055004075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021. METHODS Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1–8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9–10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis. RESULTS Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed. CONCLUSIONS The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels.
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Affiliation(s)
- Aluísio J D Barros
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Cesar G Victora
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Ana M B Menezes
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Bernardo L Horta
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Fernando C Barros
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Fernando P Hartwig
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Gabriel D Victora
- The Rockefeller University. Laboratory for Lymphocyte Dynamics. New York, NY, USA
| | - Luis Paulo Vidaletti
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Mariângela F Silveira
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Marilia A Mesenburg
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil.,Universidade Federal de Ciências da Saúde de Porto Alegre. Departamento de Saúde Coletiva. Porto Alegre, RS Brasil
| | - Nadège Jacques
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Cláudio J Struchiner
- Fundação Getúlio Vargas. Escola de Matemática Aplicada. Rio de Janeiro, RJ, Brasil
| | - Flávia Roberta Brust
- Universidade Federal de Ciências da Saúde de Porto Alegre. Departamento de Saúde Coletiva. Porto Alegre, RS Brasil
| | - Marinel M Dall'Agnol
- Universidade Federal de Santa Maria. Centro de Ciências da Saúde. Departamento de Saúde Coletiva. Santa Maria, RS, Brasil
| | - Ana Paula Longaray Delamare
- Universidade de Caxias do Sul. Instituto de Biotecnologia. Programa de Pós-Graduação em Biotecnologia. Caxias do Sul, RS, Brasil
| | - Carlos Henrique R François
- Universidade Regional do Noroeste do Estado do Rio Grande do Sul. Faculdade de Medicina. Ijuí, RS, Brasil
| | - Maria Letícia R Ikeda
- Universidade do Vale do Rio dos Sinos. Curso de Enfermagem. Programa de Pós-Graduação em Saúde Coletiva. São Leopoldo, RS, Brasil
| | - Débora C P Pellegrini
- Universidade Federal do Pampa - Campus Uruguaiana. Programa de Pós-Graduação em Ciência Animal. Uruguaiana, RS, Brasil
| | - Cézane Priscila Reuter
- Universidade de Santa Cruz do Sul. Departamento de Ciências da Saúde. Programa de Pós-Graduação em Promoção da Saúde. Santa Cruz do Sul, RS, Brasil
| | - Shana G da Silva
- Universidade Federal da Fronteira Sul. Curso de Medicina. Programa de Pós-Graduação em Ciências Biomédicas. Passo Fundo, RS, Brasil
| | - Odir A Dellagostin
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
| | - Pedro C Hallal
- Universidade Federal de Pelotas. Faculdade de Medicina. Programa de Pós-Graduação em Epidemiologia. Pelotas, RS, Brasil
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da Silva Francisco Junior R, Lamarca AP, de Almeida LGP, Cavalcante L, Machado DT, Martins Y, Brustolini O, Gerber AL, de C Guimarães AP, Gonçalves RB, Alves C, Mariani D, Cruz TF, de Souza IV, de Carvalho EM, Ribeiro MS, Carvalho S, da Silva FD, de Oliveira Garcia MH, de Souza LM, da Silva CG, Ribeiro CLP, Cavalcanti AC, de Mello CMB, Struchiner CJ, Tanuri A, Vasconcelos ATR. Turnover of SARS-CoV-2 Lineages Shaped the Pandemic and Enabled the Emergence of New Variants in the State of Rio de Janeiro, Brazil. Viruses 2021; 13:2013. [PMID: 34696443 PMCID: PMC8537965 DOI: 10.3390/v13102013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/23/2021] [Accepted: 09/29/2021] [Indexed: 01/02/2023] Open
Abstract
In the present study, we provide a retrospective genomic epidemiology analysis of the SARS-CoV-2 pandemic in the state of Rio de Janeiro, Brazil. We gathered publicly available data from GISAID and sequenced 1927 new genomes sampled periodically from March 2021 to June 2021 from 91 out of the 92 cities of the state. Our results showed that the pandemic was characterized by three different phases driven by a successive replacement of lineages. Interestingly, we noticed that viral supercarriers accounted for the overwhelming majority of the circulating virus (>90%) among symptomatic individuals in the state. Moreover, SARS-CoV-2 genomic surveillance also revealed the emergence and spread of two new variants (P.5 and P.1.2), firstly reported in this study. Our findings provided important lessons learned from the different epidemiological aspects of the SARS-CoV-2 dynamic in Rio de Janeiro. Altogether, this might have a strong potential to shape future decisions aiming to improve public health management and understanding mechanisms underlying virus dispersion.
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Affiliation(s)
- Ronaldo da Silva Francisco Junior
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Alessandra P Lamarca
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Luiz G P de Almeida
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Liliane Cavalcante
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Douglas Terra Machado
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Yasmmin Martins
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Otávio Brustolini
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Alexandra L Gerber
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Ana Paula de C Guimarães
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Reinaldo Bellini Gonçalves
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
| | - Cassia Alves
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-570, Brazil; (C.A.); (D.M.); (T.F.C.); (A.T.)
| | - Diana Mariani
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-570, Brazil; (C.A.); (D.M.); (T.F.C.); (A.T.)
| | - Thais Felix Cruz
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-570, Brazil; (C.A.); (D.M.); (T.F.C.); (A.T.)
| | | | - Erika Martins de Carvalho
- Unidades de Apoio ao Diagnóstico da COVID-19, Rio de Janeiro 21040-900, Brazil; (I.V.d.S.); (E.M.d.C.)
| | - Mario Sergio Ribeiro
- Secretaria Estadual de Saúde do Rio de Janeiro, Rio de Janeiro 20031-142, Brazil; (M.S.R.); (S.C.); (C.M.B.d.M.)
| | - Silvia Carvalho
- Secretaria Estadual de Saúde do Rio de Janeiro, Rio de Janeiro 20031-142, Brazil; (M.S.R.); (S.C.); (C.M.B.d.M.)
| | - Flávio Dias da Silva
- Secretaria Municipal de Saúde Rio de Janeiro, Rio de Janeiro 20211-901, Brazil; (F.D.d.S.); (M.H.d.O.G.); (C.L.P.R.)
| | | | - Leandro Magalhães de Souza
- Laboratório Central de Saúde Pública Noel Nutels, Rio de Janeiro 20231-092, Brazil; (L.M.d.S.); (C.G.d.S.); (A.C.C.)
| | - Cristiane Gomes da Silva
- Laboratório Central de Saúde Pública Noel Nutels, Rio de Janeiro 20231-092, Brazil; (L.M.d.S.); (C.G.d.S.); (A.C.C.)
| | - Caio Luiz Pereira Ribeiro
- Secretaria Municipal de Saúde Rio de Janeiro, Rio de Janeiro 20211-901, Brazil; (F.D.d.S.); (M.H.d.O.G.); (C.L.P.R.)
| | - Andréa Cony Cavalcanti
- Laboratório Central de Saúde Pública Noel Nutels, Rio de Janeiro 20231-092, Brazil; (L.M.d.S.); (C.G.d.S.); (A.C.C.)
| | - Claudia Maria Braga de Mello
- Secretaria Estadual de Saúde do Rio de Janeiro, Rio de Janeiro 20031-142, Brazil; (M.S.R.); (S.C.); (C.M.B.d.M.)
| | | | - Amilcar Tanuri
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-570, Brazil; (C.A.); (D.M.); (T.F.C.); (A.T.)
| | - Ana Tereza R Vasconcelos
- Laboratório de Bioinformática, Laboratório Nacional de Computação Científica, Petrópolis 25651-076, Brazil; (R.d.S.F.J.); (A.P.L.); (L.G.P.d.A.); (L.C.); (D.T.M.); (Y.M.); (O.B.); (A.L.G.); (A.P.d.C.G.); (R.B.G.)
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Hallal PC, Victora CG, Silveira MF, Barros AJD, Menezes AMB, Horta BL, Struchiner CJ, Hartwig FP, Victora GD, Pellanda LC, Burattini MN, Dellagostin OA, Barros FC. The challenge of conducting epidemiological research in times of pandemic and denialism: 1-year anniversary of the EPICOVID-19 project in Brazil. Int J Epidemiol 2021; 50:1049-1052. [PMID: 34215876 DOI: 10.1093/ije/dyab129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Pedro C Hallal
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Cesar G Victora
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Mariângela F Silveira
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Aluísio J D Barros
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Ana M B Menezes
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Bernardo L Horta
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | | | - Fernando P Hartwig
- Postgraduate Program in Epidemiology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Gabriel D Victora
- Laboratory of Lymphocyte Dynamics, Rockefeller University, New York, USA
| | - Lúcia C Pellanda
- Universidade Federal de Ciências de Saúde de Porto Alegre, Porto Alegre, Brazil
| | | | - Odir A Dellagostin
- Postgraduate Program in Biotechnology, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Fernando C Barros
- Postgraduate Program in Health and Behavior, Universidade Católica de Pelotas, Pelotas, Brazil
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4
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Barros FC, Hartwig FP, Barros AJD, Menezes AMB, Horta BL, Struchiner CJ, Vidaletti LP, Silveira MF, Mesenburg MA, Delagostin OA, Hallal PC, Victora CG. COVID-19 and social distancing among children and adolescents in Brazil. Rev Saude Publica 2021; 55:42. [PMID: 34190899 PMCID: PMC8225319 DOI: 10.11606/s1518-8787.2021055003832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE To estimate the prevalence of SARS-CoV-2 antibodies and the adherence to measures of social distancing in children and adolescents studied in three national surveys conducted in Brazil between May-June 2020. METHODS Three national serological surveys were conducted in 133 sentinel cities located in all 27 Federative Units. Multistage probability sampling was used to select 250 individuals per city. The total sample size in age ranges 0-9 and 10-19 years old are of 4,263 and 8,024 individuals, respectively. Information on children or adolescents was gathered with a data collection app, and a rapid point-of-case test for SARS-CoV-2 was conducted on a finger prick blood sample. RESULTS The adjusted prevalence of antibodies was 2.9% (2.2-3.6) among children 0-9 years, 2.2% (1.8-2.6) among adolescents 10-19 years, and 3.0% (2.7-3.3) among adults 20+years. Prevalence of antibodies was higher among poor children and adolescents compared to those of rich families. Adherence to social distancing measures was seen in 72.4% (71.9-73.8) of families with children, 60.8% (59.6-61.9) for adolescents, and 57.4% (56.9-57.8) for adults. For not leaving the house except for essential matters the proportions were 81.7% (80.5-82.9), 70.6% (69.6-61.9), and 65.1% (64.7-65.5), respectively. Among children and adolescents, social distancing was strongly associated with socioeconomic status, being much higher in the better-off families. CONCLUSIONS The prevalence of antibodies against SARS-CoV-2 showed comparable levels among children, adolescents, and adults. Adherence to social distancing measures was more prevalent in children, followed by adolescents. There were important socioeconomic differences in the adherence to social distancing among children and adolescents.
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Affiliation(s)
- Fernando C Barros
- Universidade Católica de PelotasPelotasRSBrasilUniversidade Católica de Pelotas. Curso de Pós-Graduação em Saúde no Ciclo Vital. Pelotas, RS, Brasil
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Fernando P Hartwig
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Aluísio J D Barros
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Ana M B Menezes
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Bernardo L Horta
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Cláudio J Struchiner
- Fundação Getúlio VargasEscola de Matemática AplicadaRio de JaneiroRJBrasilFundação Getúlio Vargas. Escola de Matemática Aplicada. Rio de Janeiro, RJ, Brasil
| | - Luis Paulo Vidaletti
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Mariangela F Silveira
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Marilia A Mesenburg
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
- Universidade Federal de Ciências da Saúde de Porto AlegreFaculdade de MedicinaPorto AlegreRSBrasilUniversidade Federal de Ciências da Saúde de Porto Alegre. Faculdade de Medicina. Porto Alegre, RS, Brasil
| | - Odir A Delagostin
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Pedro C Hallal
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
| | - Cesar G Victora
- Universidade Federal de PelotasFaculdade de MedicinaDepartamento de Medicina SocialPelotasRSBrasilUniversidade Federal de Pelotas. Faculdade de Medicina. Departamento de Medicina Social. Pelotas, RS, Brasil
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Menezes AMB, Victora CG, Hartwig FP, Silveira MF, Horta BL, Barros AJD, Mesenburg MA, Wehrmeister FC, Pellanda LC, Dellagostin OA, Struchiner CJ, Burattini MN, Barros FC, Hallal PC. High prevalence of symptoms among Brazilian subjects with antibodies against SARS-CoV-2. Sci Rep 2021; 11:13279. [PMID: 34168250 PMCID: PMC8225900 DOI: 10.1038/s41598-021-92775-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 06/15/2021] [Indexed: 12/13/2022] Open
Abstract
Since the beginning of the pandemic of COVID-19, there has been a widespread assumption that most infected persons are asymptomatic. Using data from the recent wave of the EPICOVID19 study, a nationwide household-based survey including 133 cities from all states of Brazil, we estimated the proportion of people with and without antibodies for SARS-CoV-2 who were asymptomatic, which symptoms were most frequently reported, number of symptoms and the association with socio-demographic characteristics. We tested 33,205 subjects using a rapid antibody test previously validated. Information was collected before participants received the test result. Out of 849 (2.7%) participants positive for SARS-CoV-2 antibodies, only 12.1% (95% CI 10.1-14.5) reported no symptoms, compared to 42.2% (95% CI 41.7-42.8) among those negative. The largest difference between the two groups was observed for changes in smell/taste (56.5% versus 9.1%, a 6.2-fold difference). Changes in smell/taste, fever and body aches were most likely to predict positive tests as suggested by recursive partitioning tree analysis. Among individuals without any of these three symptoms, only 0.8% tested positive, compared to 18.3% of those with both fever and changes in smell or taste. Most subjects with antibodies against SARS-CoV-2 are symptomatic, even though most present only mild symptoms.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Lúcia C Pellanda
- Fundação Universidade Federal de Ciências de Saúde de Porto Alegre, Porto Alegre, Brazil
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Farias DR, Alves-Santos NH, Eshriqui I, Martins MC, Struchiner CJ, Lepsch J, Costa N, Kac G. Leptin gene polymorphism (rs7799039; G2548A) is associated with changes in serum lipid concentrations during pregnancy: a prospective cohort study. Eur J Nutr 2019; 59:1999-2009. [PMID: 31292750 DOI: 10.1007/s00394-019-02049-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 07/05/2019] [Indexed: 12/20/2022]
Abstract
PURPOSE Little is known about the effects of leptin and leptin receptor polymorphisms on lipid changes during pregnancy. The aims of this study were to evaluate the associations between the single nucleotide polymorphisms (SNPs) of leptin and leptin receptor genes and the lipid concentrations during pregnancy; and to test whether dietary intake is a mediator in these associations. METHODS A prospective cohort of 154 pregnant women was followed up in Rio de Janeiro, Brazil during the following gestational periods: 5-13th, 20-26th and 30-36th weeks. HDL-C, total cholesterol (TC) and triglyceride (TG) were measured by the enzymatic colorimetric method, and LDL-C was calculated. DNA was extracted by the phenol-chloroform method, and leptin (G2548A, rs7799039) and leptin receptor SNPs (Q223R; rs1137101 and K109R; rs1137100) were genotyped using real-time PCR. Statistical analyses included linear mixed-effect models. RESULTS Women with the AA genotype of G2548A polymorphism reported a higher fat and total energy intake and had a higher increase in TG concentration during pregnancy than women with AG or GG genotype. The association between G2548A SNP and TG concentrations was not attenuated by adjusting for total lipid (g) and energy (kcal) intake. We did not observe significant associations between the Q223R and K109R SNPs and the lipid concentrations. CONCLUSIONS Women homozygous for the A allele of the leptin SNP (G2548A) had a higher increase in TG concentrations per gestational week compared with women with the AG or GG genotype. This is an exploratory and hypothesis-generating study, and the results need confirmation in studies with larger sample sizes.'
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Affiliation(s)
- Dayana Rodrigues Farias
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Nadya Helena Alves-Santos
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Ilana Eshriqui
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Maisa Cruz Martins
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Cláudio J Struchiner
- Escola de Matemática Aplicada, Fundação Getúlio Vargas, Praia de Botafogo 190, Rio de Janeiro, RJ, 22250-900, Brazil
| | - Jaqueline Lepsch
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Nathalia Costa
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Gilberto Kac
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, 373, CCS, Bloco, J2-sala 29, Cidade Universitária-Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil.
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Fernández-Medina RD, Carareto CMA, Struchiner CJ, Ribeiro JMC. Transposable elements in the Anopheles funestus transcriptome. Genetica 2017; 145:275-293. [PMID: 28424974 DOI: 10.1007/s10709-017-9964-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 03/27/2017] [Indexed: 12/27/2022]
Abstract
Transposable elements (TEs) are present in most of the eukaryotic genomes and their impact on genome evolution is increasingly recognized. Although there is extensive information on the TEs present in several eukaryotic genomes, less is known about the expression of these elements at the transcriptome level. Here we present a detailed analysis regarding the expression of TEs in Anopheles funestus, the second most important vector of human malaria in Africa. Several transcriptionally active TE families belonging both to Class I and II were identified and characterized. Interestingly, we have identified a full-length putative active element (including the presence of full length TIRs in the genomic sequence) belonging to the hAT superfamily, which presents active members in other insect genomes. This work contributes to a comprehensive understanding of the landscape of transposable elements in A. funestus transcriptome. Our results reveal that TEs are abundant and diverse in the mosquito and that most of the TE families found in the genome are represented in the mosquito transcriptome, a fact that could indicate activity of these elements.The vast diversity of TEs expressed in A. funestus suggests that there is ongoing amplification of several families in this organism.
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Affiliation(s)
- Rita D Fernández-Medina
- Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública, Av. Brasil, 4365, Rio de Janeiro, Brazil.
| | - Claudia M A Carareto
- Departamento de Biologia, UNESP-Universidade Estadual Paulista, Rua Cristóvão Colombo, 2265, São José do Rio Preto, SP, Brazil
| | - Cláudio J Struchiner
- Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública, Av. Brasil, 4365, Rio de Janeiro, Brazil
| | - José M C Ribeiro
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD, 20852, USA
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8
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Farias DR, Franco-Sena AB, Rebelo F, Salles GF, Struchiner CJ, Martins MC, Kac G. Polymorphisms of Leptin (G2548A) and Leptin Receptor (Q223R and K109R) Genes and Blood Pressure During Pregnancy and the Postpartum Period: A Cohort. Am J Hypertens 2017; 30:130-140. [PMID: 28077420 DOI: 10.1093/ajh/hpw147] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/01/2016] [Accepted: 10/27/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The genetic component related to blood pressure (BP) changes during pregnancy is still not elucidated. Thus, the aim of the study was to evaluate the association between leptin and leptin receptor polymorphisms and systolic (SBP) and diastolic BP (DBP) variation during pregnancy and the postpartum period. METHODS Prospective cohort of 146 women followed at a Public Health Center in Rio de Janeiro, Brazil, during pregnancy and the postpartum. SBP and DBP (mm Hg) were measured using an automatic sphygmomanometer. DNA was extracted by phenol-chloroform protocol and leptin (G2548A) and leptin receptor genes (Q223R and K109R) polymorphisms were genotyped using real-time PCR method. Statistical analyses included longitudinal linear mixed-effect models. RESULTS Adjusted longitudinal models showed that women carrying the G-allele of leptin gene's polymorphism began pregnancy with higher BP levels compared to the AA genotype and their levels remained higher throughout pregnancy and the postpartum period (β SBP = 4.5; 95% confidence interval (CI) = 1.0-8.0; P = 0.012; β DBP = 2.9; 95% CI = 0.1-5.8; P = 0.040). There was a significant interaction between leptin gene polymorphism and body mass index (BMI), in which the effect of BMI on increasing BP was steeper in women homozygous for the A-allele, compared with those who had at least one G-allele (β G-allele#BMI = -0.8; 95% CI = -1.5 to -0.1; P = 0.022). We did not find significant associations between leptin receptor polymorphisms and BP changes. CONCLUSIONS The G-allele of leptin gene polymorphism (G2548A) was associated with increased BP levels during pregnancy and the postpartum. Furthermore, leptin polymorphism genotypes seem to modify the well-known effect of BMI on BP.
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Affiliation(s)
- Dayana R Farias
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Department of Social and Applied Nutrition, Graduate Program in Nutrition, Institute of Nutrition Josué de Castro, Rio de Janeiro Federal University, Rio de Janeiro, Brazil
| | - Ana B Franco-Sena
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Department of Social Nutrition, Emilia de Jesus Ferreiro Nutrition School, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Fernanda Rebelo
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Division of Clinical Trials and Drug Development, National Institute of Cancer, Ministry of Health, Rio de Janeiro, Brazil
| | - Gil F Salles
- Department of Internal Medicine, University Hospital Clementino Fraga Filho, School of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cláudio J Struchiner
- Department of Endemic Diseases, National School of Public Health, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Maisa C Martins
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Department of Social and Applied Nutrition, Graduate Program in Nutrition, Institute of Nutrition Josué de Castro, Rio de Janeiro Federal University, Rio de Janeiro, Brazil
| | - Gilberto Kac
- Nutritional Epidemiology Observatory, Department of Social and Applied Nutrition, Institute of Nutrition Josué de Castro, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil;
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Arcà B, Struchiner CJ, Pham VM, Sferra G, Lombardo F, Pombi M, Ribeiro JMC. Positive selection drives accelerated evolution of mosquito salivary genes associated with blood-feeding. Insect Mol Biol 2014; 23:122-31. [PMID: 24237399 PMCID: PMC3909869 DOI: 10.1111/imb.12068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The saliva of bloodsucking animals contains dozens to hundreds of proteins that counteract their hosts' haemostasis, inflammation and immunity. It was previously observed that salivary proteins involved in haematophagy are much more divergent in their primary sequence than those of housekeeping function, when comparisons were made between closely related organisms. While this pattern of evolution could result from relaxed selection or drift, it could alternatively be the result of positive selection driven by the intense pressure of the host immune system. We investigated the polymorphism of five different genes associated with blood-feeding in the mosquito Anopheles gambiae and obtained evidence in four genes for sites with signatures of positive selection. These results add salivary gland genes from bloodsucking arthropods to the small list of genes driven by positive selection.
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Affiliation(s)
- Bruno Arcà
- Department of Public Health and Infectious Diseases, Parasitology Section, Sapienza University of Rome, P. le Aldo Moro 5 – 00185 Roma, Italy
| | - Cláudio J. Struchiner
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Av. Leopoldo Bulhões 1480, Manguinhos, 21041-210, Rio de Janeiro, Brazil
| | - Van M. Pham
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway room 2E32D, Rockville, MD 20852, USA
| | - Gabriella Sferra
- Department of Public Health and Infectious Diseases, Parasitology Section, Sapienza University of Rome, P. le Aldo Moro 5 – 00185 Roma, Italy
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases, Parasitology Section, Sapienza University of Rome, P. le Aldo Moro 5 – 00185 Roma, Italy
| | - Marco Pombi
- Department of Public Health and Infectious Diseases, Parasitology Section, Sapienza University of Rome, P. le Aldo Moro 5 – 00185 Roma, Italy
| | - José M. C. Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway room 2E32D, Rockville, MD 20852, USA
- To whom correspondence should be addressed.
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10
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Maciel-de-Freitas R, Aguiar R, Bruno RV, Guimarães MC, Lourenço-de-Oliveira R, Sorgine MHF, Struchiner CJ, Valle D, O'Neill SL, Moreira LA. Why do we need alternative tools to control mosquito-borne diseases in Latin America? Mem Inst Oswaldo Cruz 2013; 107:828-9. [PMID: 22990977 DOI: 10.1590/s0074-02762012000600021] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 09/04/2012] [Indexed: 11/21/2022] Open
Abstract
In this opinion paper, we discuss the potential and challenges of using the symbiont Wolbachia to block mosquito transmitted diseases such as dengue, malaria and chikungunya in Latin America.
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Affiliation(s)
- Rafael Maciel-de-Freitas
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
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11
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Fernández-Medina RD, Ribeiro JMC, Carareto CMA, Velasque L, Struchiner CJ. Losing identity: structural diversity of transposable elements belonging to different classes in the genome of Anopheles gambiae. BMC Genomics 2012; 13:272. [PMID: 22726298 PMCID: PMC3442997 DOI: 10.1186/1471-2164-13-272] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/08/2012] [Indexed: 01/10/2023] Open
Abstract
Background Transposable elements (TEs), both DNA transposons and retrotransposons, are genetic elements with the main characteristic of being able to mobilize and amplify their own representation within genomes, utilizing different mechanisms of transposition. An almost universal feature of TEs in eukaryotic genomes is their inability to transpose by themselves, mainly as the result of sequence degeneration (by either mutations or deletions). Most of the elements are thus either inactive or non-autonomous. Considering that the bulk of some eukaryotic genomes derive from TEs, they have been conceived as “TE graveyards.” It has been shown that once an element has been inactivated, it progressively accumulates mutations and deletions at neutral rates until completely losing its identity or being lost from the host genome; however, it has also been shown that these “neutral sequences” might serve as raw material for domestication by host genomes. Results We have analyzed the sequence structural variations, nucleotide divergence, and pattern of insertions and deletions of several superfamilies of TEs belonging to both class I (long terminal repeats [LTRs] and non-LTRs [NLTRs]) and II in the genome of Anopheles gambiae, aiming at describing the landscape of deterioration of these elements in this particular genome. Our results describe a great diversity in patterns of deterioration, indicating lineage-specific differences including the presence of Solo-LTRs in the LTR lineage, 5′-deleted NLTRs, and several non-autonomous and MITEs in the class II families. Interestingly, we found fragments of NLTRs corresponding to the RT domain, which preserves high identity among them, suggesting a possible remaining genomic role for these domains. Conclusions We show here that the TEs in the An. gambiae genome deteriorate in different ways according to the class to which they belong. This diversity certainly has implications not only at the host genomic level but also at the amplification dynamic and evolution of the TE families themselves.
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Affiliation(s)
- Rita D Fernández-Medina
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
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12
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Abstract
Background Transposable elements (TEs) are DNA sequences, present in the genome of most eukaryotic organisms that hold the key characteristic of being able to mobilize and increase their copy number within chromosomes. These elements are important for eukaryotic genome structure and evolution and lately have been considered as potential drivers for introducing transgenes into pathogen-transmitting insects as a means to control vector-borne diseases. The aim of this work was to catalog the diversity and abundance of TEs within the Anopheles gambiae genome using the PILER tool and to consolidate a database in the form of a hyperlinked spreadsheet containing detailed and readily available information about the TEs present in the genome of An. gambiae. Results Here we present the spreadsheet named AnoTExcel that constitutes a database with detailed information on most of the repetitive elements present in the genome of the mosquito. Despite previous work on this topic, our approach permitted the identification and characterization both of previously described and novel TEs that are further described in detailed. Conclusions Identification and characterization of TEs in a given genome is important as a way to understand the diversity and evolution of the whole set of TEs present in a given species. This work contributes to a better understanding of the landscape of TEs present in the mosquito genome. It also presents a novel platform for the identification, analysis, and characterization of TEs on sequenced genomes.
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Affiliation(s)
- Rita D Fernández-Medina
- Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública Sergio Arouca, Av, Brasil, 4365, 21040 360, Rio de Janeiro, Brazil.
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13
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Estrela RDC, Ribeiro FS, Barroso PF, Tuyama M, Gregório SP, Dias-Neto E, Struchiner CJ, Suarez-Kurtz G. ABCB1 polymorphisms and the concentrations of lopinavir and ritonavir in blood, semen and saliva of HIV-infected men under antiretroviral therapy. Pharmacogenomics 2009; 10:311-8. [PMID: 19207033 DOI: 10.2217/14622416.10.2.311] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION Lopinavir and ritonavir are frequently included in highly active antiretroviral therapy (HAART) regimens for HIV infection. These drugs are substrates, and may also inhibit and/or induce the P-glycoprotein (ABCB1) transporter, encoded by the polymorphic ABCB1 gene. We investigated the impact of three common exonic ABCB1 polymorphisms on the concentrations of lopinavir and ritonavir in blood, semen and saliva of HIV-infected men under stable HAART containing ritonavir-boosted lopinavir. MATERIALS & METHODS Blood, semen and saliva samples were collected from 113 subjects, 30-35 minutes before the scheduled morning dose of lopinavir/ritonavir, and trough drug concentrations were measured using LC/MS/MS. The 1236C>T, 2677G>T/A and 3435C>T polymorphisms were genotyped using the single base extension-termination method and ABCB1 haplotypes were statistically inferred. RESULTS Median (25th-75th percentile) trough concentrations (ng/ml) of lopinavir in plasma, semen and saliva were 6326 (4070-8617), 286.0 (128.4-475.5) and 72.7 (38.0-119.6), respectively. The corresponding concentrations (ng/ml) for ritonavir were 261.8 (172.2-398.6), 17.7 (9.2-27.6) and 5.3 (3.2-9.0), respectively. Univariate and multivariate regression analysis revealed no influence of ABCB1 genotypes or haplotypes on the concentrations of lopinavir and ritonavir in plasma, semen and saliva of HIV-infected men under stable HAART treatment. CONCLUSION The ABCB1 1236C>T, 2667G>T/A and 3435C>T genotypes and haplotypes are not predictors of lopinavir and ritonavir concentrations in blood plasma, semen or saliva of HIV-infected men under stable HAART treatment. The concentrations of lopinavir and ritonavir in saliva are not reliable predictors of the concentration of these drugs in semen.
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Affiliation(s)
- Rita de Cassia Estrela
- Divisão de Farmacologia, Instituto Nacional de Câncer, Rua André Cavalcanti 37, Rio de Janeiro 21230-050, Brazil
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14
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Estrela RCE, Ribeiro FS, Carvalho RS, Gregório SP, Dias-Neto E, Struchiner CJ, Suarez-Kurtz G. Distribution of ABCB1 polymorphisms among Brazilians: impact of population admixture. Pharmacogenomics 2008; 9:267-76. [PMID: 18303963 DOI: 10.2217/14622416.9.3.267] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
INTRODUCTION Interethnic admixture is a source of cryptic population structure that may lead to spurious genotype-phenotype associations in pharmacogenomic studies. We studied the impact of population stratification on the distribution of ABCB1 polymorphisms (1236C>T, 2677G>T/A and 3435C>T) among Brazilians, a highly admixed population with Amerindian, European and African ancestral roots. METHODS Individual DNA from 320 healthy adults was genotyped with a panel of ancestry informative markers, and the proportions of African component of ancestry (ACA) were estimated. ABCB1 genotypes were determined by the single base extension/termination method. We describe the association between ABCB1 polymorphisms and ACA by fitting a linear proportional odds logistic regression model to the data. RESULTS The distribution of the ABCB1 2677G>T/A and 3435C>T, but not the 1236C>T, SNPs displayed a significant trend for decreasing frequency of the T alleles and TT genotypes from White to Intermediate to Black individuals. The same trend was observed in the frequency of the T/nonG/T haplotype at the 1236, 2677 and 3435 loci. When the population sample was proportioned in quartiles, according to the individual ACA estimates, the frequency of the T allele and TT genotype at each locus declined progressively from the lowest (< 0.25 ACA) to the highest (> 0.75 ACA) quartile. Linear proportional odds logistic regression analysis confirmed that the odds of having the T allele at each locus decreases in a continuous manner with the increase of the ACA, throughout the ACA range (0.13-0.94) observed in the overall population sample. A significant association was also detected between the individual ACA estimates and the presence of the T/nonG/T haplotype in the overall population. CONCLUSION Self-identification according to the racial/color categories proposed by the Brazilian Census is insufficient to properly control for population stratification in pharmacogenomic studies of ABCB1.
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Affiliation(s)
- Rita C E Estrela
- Divisão de Farmacologia, Instituto Nacional de Câncer, Rua André Cavalcanti 37, Rio de Janeiro 21230-050, Brazil
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15
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Velasque LS, Estrela RCE, Suarez-Kurtz G, Struchiner CJ. A new model for the population pharmacokinetics of didanosine in healthy subjects. ACTA ACUST UNITED AC 2007; 40:97-104. [PMID: 17225002 DOI: 10.1590/s0100-879x2007000100013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Accepted: 03/09/2006] [Indexed: 11/22/2022]
Abstract
Didanosine (ddI) is a component of highly active antiretroviral therapy drug combinations, used especially in resource-limited settings and in zidovudine-resistant patients. The population pharmacokinetics of ddI was evaluated in 48 healthy volunteers enrolled in two bioequivalence studies. These data, along with a set of co-variates, were the subject of a nonlinear mixed-effect modeling analysis using the NONMEM program. A two-compartment model with first order absorption (ADVAN3 TRANS3) was fitted to the serum ddI concentration data. Final pharmacokinetic parameters, expressed as functions of the co-variates gender and creatinine clearance (CL CR), were: oral clearance (CL = 55.1 + 240 x CL CR + 16.6 L/h for males and CL = 55.1 + 240 x CL CR for females), central volume (V2 = 9.8 L), intercompartmental clearance (Q = 40.9 L/h), peripheral volume (V3 = 62.7 + 22.9 L for males and V3 = 62.7 L for females), absorption rate constant (Ka = 1.51/h), and dissolution time of the tablet (D = 0.43 h). The intraindividual (residual) variability expressed as coefficient of variation was 13.0%, whereas the interindividual variability of CL, Q, V3, Ka, and D was 20.1, 75.8, 20.6, 18.9, and 38.2%, respectively. The relatively high (>30%) interindividual variability for some of these parameters, observed under the controlled experimental settings of bioequivalence trials in healthy volunteers, may result from genetic variability of the processes involved in ddI absorption and disposition.
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Affiliation(s)
- L S Velasque
- Programa de Computação Científica, Fundação Oswaldo Cruz, Brasil.
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16
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Abstract
In randomized trials, the treatment assignment mechanism is independent of the outcome of interest and other covariates thought to be relevant in determining this outcome. It also allows, on average, for a balanced distribution of these covariates in the vaccine and placebo groups. Randomization, however, does not guarantee that the estimated effect is an unbiased estimate of the biological effect of interest. We show how exposure to infection can be a confounder even in randomized vaccine field trials. Based on a simple model of the biological efficacy of interest, we extend the arguments on comparability and collapsibility to examine the limits of randomization to control for unmeasured covariates. Estimates from randomized, placebo-controlled Phase III vaccine field trials that differ in baseline transmission are not comparable unless explicit control for baseline transmission is taken into account.
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Affiliation(s)
- C J Struchiner
- IMS/UERJ and Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
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17
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Massad E, Coutinho FAB, Burattini MN, Lopez LF, Struchiner CJ. The impact of imperfect vaccines on the evolution of HIV virulence. Med Hypotheses 2006; 66:907-11. [PMID: 16442745 DOI: 10.1016/j.mehy.2005.11.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 11/16/2005] [Accepted: 11/22/2005] [Indexed: 12/01/2022]
Abstract
A theoretical framework is proposed on which some hypotheses related to the impact of imperfect vaccines on the evolution of HIV virulence can be tested. For this, a linear increase of risk behaviour with vaccine efficacy is assumed. This is based on the hypothesis that people are prone to relax preventive measures by knowing that they and their partners are vaccinated and that this effect is more intense the more effective the vaccine is known to be. An additional, and perhaps more important hypothesis is related to the theoretical possibility that increased risk behaviour of some vaccinated individuals in partially protected populations could act as a selective pressure toward more virulent HIV strains. Those hypotheses were tested by a mathematical model that considers three different HIV strains competing against each other in a population partially protected by imperfect vaccines of distinct efficacies. Simulations of the model demonstrated that, under the above hypotheses, there is a shift in HIV virulence towards more aggressive strains with increase in vaccine efficacy, associated with a marked reduction in the total amount of transmission and, consequently, in the prevalence of HIV. Potential ways for further testing the theory/model and the implications of the results are discussed.
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Affiliation(s)
- E Massad
- School of Medicine, The University of São Paulo and LIM 01/HCFMUSP, Brazil.
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18
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Luz PM, Codeço CT, Werneck GL, Struchiner CJ. A modelling analysis of pertussis transmission and vaccination in Rio de Janeiro, Brazil. Epidemiol Infect 2005; 134:850-62. [PMID: 16316489 PMCID: PMC2870440 DOI: 10.1017/s095026880500539x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2005] [Indexed: 11/07/2022] Open
Abstract
Pertussis is an infectious respiratory disease for which mass vaccination is an effective preventive strategy. In many developed countries, where high vaccination coverage has been maintained for approximately 50 years, re-emergence of the disease has been observed in all age groups. In the municipality of Rio de Janeiro (RJ), where vaccination started in the 1980s, surveillance data show no sign of disease re-emergence. We developed a mathematical model that incorporates the major demographic aspects of a large urban centre in a developing nation, in addition to the most important epidemiological aspects of disease transmission. Parameter values were estimated based on RJ demographic and vaccine coverage data. Overall, all vaccination strategies determined a major decrease (over 95% decrease when compared to the pre-vaccine era) in the incidence of primary infections (occurring in individuals who have never been immunized through infection or vaccine). On the other hand, the strategies (a) three doses at age 2-11 months, (b) three doses plus booster at age 12-23 months, (c) three doses plus booster at age 4-5 years, and (d) three doses plus both boosters, differently affected the incidence of secondary infections (occurring in previously infected/vaccinated individuals). Given that the immunity against pertussis wanes with time and that the infectious agent has not been eliminated from the population, it is expected that pertussis will continue to be a problem in RJ. Actually, since immunity acquired from vaccine wanes faster than disease-acquired immunity and the possibility of natural boosters has decreased with mass vaccination, an increase in the incidence of secondary infections among older age groups is expected (and predicted by the model). Possible explanations as to why this dynamics is not captured by the RJ surveillance system are discussed. A poorly effective surveillance system and a lack of awareness regarding loss of immunity and the possibility of pertussis infection in older age groups are among them. Finally, we bring attention to the need of (i) field studies for the measurement of pertussis incidence in adolescents and adults; (ii) better understanding of the transmission dynamics currently occurring in RJ, and (iii) re-evaluation of vaccination strategies with the possible introduction of acellular vaccines for the vaccination of older individuals.
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Affiliation(s)
- P M Luz
- Programa de Computação Científica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
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Luz PM, Codeço CT, Struchiner CJ, Werneck GL. 549-S: A Mathematical Analysis of Pertussis Re-Emergence in Rio De Janeiro, Brazil. Am J Epidemiol 2005. [DOI: 10.1093/aje/161.supplement_1.s138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- P M Luz
- Scientific Computing Program, Oswaldo Cruz Foundation and Social Medicine Institute, Rio de Janeiro State University
| | - C T Codeço
- Scientific Computing Program, Oswaldo Cruz Foundation and Social Medicine Institute, Rio de Janeiro State University
| | - C J Struchiner
- Scientific Computing Program, Oswaldo Cruz Foundation and Social Medicine Institute, Rio de Janeiro State University
| | - G L Werneck
- Scientific Computing Program, Oswaldo Cruz Foundation and Social Medicine Institute, Rio de Janeiro State University
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Codeço CT, Luz PM, Struchiner CJ. Risk assessment of yellow fever urbanization in Rio de Janeiro, Brazil. Trans R Soc Trop Med Hyg 2005; 98:702-10. [PMID: 15485700 DOI: 10.1016/j.trstmh.2003.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Revised: 12/11/2003] [Accepted: 12/16/2003] [Indexed: 11/23/2022] Open
Abstract
Yellow fever (YF), an arthropod-borne viral disease, occurs in regions of tropical America and Africa. Sylvatic YF is endemic in the north and west of Brazil. Urban YF, on the other hand, has not been reported in the country since 1942. However, the widespread presence of the YF urban vector in Brazil has lead to concern about the potential re-emergence of YF in urban centres. Here, we assess the risk of YF emergence in the city of Rio de Janeiro, Brazil, by estimating the probability of infected individuals arriving from YF-endemic areas, and the probability of infective individuals triggering an epidemic. We found that the risk of urban YF emergence may reach values as high as 29% during the epizootic periods but the precision of the estimate is low.
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Affiliation(s)
- C T Codeço
- Programa de Computação Científica, Fundação Oswaldo Cruz, Avenida Brasil, 4365, Antiga Residencia Oficial, Rio de Janeiro, RJ 21045-900, Brazil.
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Abstract
We investigated polymorphisms of cytochrome P450 2A6 (CYP2A6) and its association with smoking habits in 412 healthy Brazilians, self-recognized as white (n=147), black (n=123) and intermediate (n=142), and classified as smokers (n=205, including 61 ex-smokers) and nonsmokers (n=207). The frequencies of the variant alleles CYP2A6(*)1B, CYP2A6(*)2, CYP2A6(*)4 and CYP2A6(*)9 in the overall study population were 29.9, 1.7, 0.5 and 5.7%, respectively. Significant differences in the CYP2A6 allelic distribution were observed across the three population subgroups. There was a statistically significant trend for decreasing frequency of CYP2A6(*)1B from white to intermediate and to black persons. An association between CYP2A6 genotype and smoking dependence was detected, which could not be explained by the expected phenotypic activity of CYP2A6. In white and intermediate persons, the odds ratio (OR) of being smokers vs nonsmokers was 0.07 (95% CI 0.02-0.20; P<0.001) and 0.27 (95% CI 0.12-0.61; P<0.001), respectively, for genotypes including allele CYP2A6(*)1B, as compared to wild-type homozygous. In contrast, the corresponding OR in black Brazilians was 1.34 (95% CI 0.57-3.17; P=0.46). These data suggest that the CYP2A6(*)1B is associated with smoking dependence in white and intermediate, but not black Brazilians.
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Affiliation(s)
- G M Vasconcelos
- Divisão de Farmacologia, Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, RJ, Brazil
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Struchiner CJ, Luz PM, Dourado I, Sato HK, Aguiar SG, Ribeiro JGL, Soares RCR, Codeço CT. Risk of fatal adverse events associated with 17DD yellow fever vaccine. Epidemiol Infect 2004; 132:939-46. [PMID: 15473158 PMCID: PMC2870182 DOI: 10.1017/s0950268804002602] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Yellow fever (YF), an acute infectious disease, is endemic in the north and central-west of Brazil. This disease can be prevented by the use of a vaccine. In Brazil, four fatal adverse events have been associated with the YF vaccine used in the country (17DD vaccine). We briefly describe the last two fatalities, and estimate the risk of 17DD-associated fatal adverse events under different epidemiological scenarios. Controversies regarding the appropriate denominator that enters the estimation of risk serve as a motivation for each proposed scenario. The statistical procedures used show optimum behaviour when assessing the risk of rare events. Risk estimates vary from 0.043 (95 % CI 0.017-0.110) to 2.131 (95 % CI 0.109-12.071) fatalities per million doses administered. The robust estimates of the risk of fatal adverse events we present constitute an important element in future risk-benefit analysis and point to the need for good quality vaccine coverage and adverse-events surveillance data to assess the risk of vaccination. Although vaccination of YF endemic regions is necessary to maintain low disease prevalence, preventive administration of YF vaccine to the entire population should be cautiously analysed.
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Affiliation(s)
- C J Struchiner
- Programa de Computação Científica, Fundação Oswaldo Cruz, Av Brasil 4365, Manguinhos, Rio de Janeiro, RJ, Brasil.
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Abstract
Malaria vaccine candidates have already been tested and new trials are being carried out. We present a brief description of specific issues of validity that are relevant when assessing vaccine efficacy in the field and illustrate how the application of these principles might improve our interpretation of the data being gathered in actual malaria vaccine field trials. Our discussion assumes that vaccine evaluation shares the same general principles of validity with epidemiologic causal inference, i.e., the process of drawing inferences from epidemiologic data aiming at the identification of causes of diseases. Judicious exercise of these principles indicates that, for meaningful interpretation, measures of vaccine efficacy require definitions based upon arguments conditional on the amount of exposure to infection, and specification of the initial and final states in which one believes the effect of interest takes place.
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Affiliation(s)
- C J Struchiner
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, 21041-210, Brazil
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Kac G, Benício MHDA, Velásquez-Meléndez G, Valente JG, Struchiner CJ. Breastfeeding and postpartum weight retention in a cohort of Brazilian women. Am J Clin Nutr 2004; 79:487-93. [PMID: 14985226 DOI: 10.1093/ajcn/79.3.487] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The relation between postpartum weight retention and breastfeeding practices is controversial. OBJECTIVE Defining breastfeeding as the period when a child is exclusively or predominantly breastfed, we studied the association between breastfeeding duration and postpartum weight retention. DESIGN We followed 405 women aged 18-45 y who were assessed at 0.5, 2, 6, and 9 mo postpartum. The outcome variable, postpartum weight retention, was expressed as the difference between the observed weight at each follow-up and the reported prepregnancy weight. The main statistical procedure used was the longitudinal mixed-effects model. RESULTS Mean postpartum weight retention at the end of the study was 3.1 kg. Single women aged > or = 30 y retained more weight than did younger single women or married women. The combined effect of breastfeeding duration and percentage of body fat at baseline was significant only for women with < 30% body fat. According to the model's prediction, when women who had 22% body fat and breastfed for 180 d were compared with those who had 22% body fat and breastfed for only 30 d, each month of breastfeeding contributed -0.44 kg to postpartum weight retention. When only the percentage of body fat was varied, the total effect was 3.0, 1.7, 1.2, and 0.04 kg in women with 18%, 25%, 28%, and 35% body fat, respectively. CONCLUSIONS These results support the hypothesis of an association between breastfeeding and postpartum weight retention and suggest that encouraging prolonged breastfeeding might contribute to decreases in postpartum weight retention.
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Affiliation(s)
- Gilberto Kac
- Department of Social and Applied Nutrition, Institute of Nutrition, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
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25
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Kac G, Benício MHDA, Velásquez-Meléndez G, Valente JG, Struchiner CJ. Gestational weight gain and prepregnancy weight influence postpartum weight retention in a cohort of brazilian women. J Nutr 2004; 134:661-6. [PMID: 14988464 DOI: 10.1093/jn/134.3.661] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The objective of the study was to test the association between gestational weight gain, reproductive factors, and postpartum weight retention based on a cohort conducted with 405 women aged 18-45 y with follow-up waves at 0.5, 2, 6, and 9 mo postpartum. The outcome variable, postpartum weight retention, was calculated as the difference between the measured weight at each visit minus the prepregnancy weight. We estimated the statistical associations between the outcome variable and potential explanatory covariates of interest by fitting a longitudinal mixed-effects model. Women with gestational weight gain above the recommendations of the Institute of Medicine (IOM) retained significantly more weight than women with weight gain within or below the recommendations, independently of prepregnancy BMI [weight (kg)/height (m(2))] or body fat at baseline. Women with the highest gestational weight gain and with body fat >/=30 g/100 g at baseline had the highest likelihood of developing maternal obesity. The final longitudinal model showed that 35% of each kilogram of weight gained during pregnancy was retained 9 mo postpartum, even after adjustment for age, prepregnancy BMI, body fat at baseline, and years since first parturition. Each unit of increase in prepregnancy BMI was associated with a decrease of -0.51 kg in postpartum weight retention. In conclusion, gestational weight gain was one of the most important predictors for postpartum weight retention and must be monitored systematically with the aim of preventing postpartum obesity and the diseases that follow.
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Affiliation(s)
- Gilberto Kac
- Department of Social and Applied Nutrition, Institute of Nutrition, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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26
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Suarez-Kurtz G, Ribeiro FM, Salvadori MC, Struchiner CJ. Carbamazepine: a bioequivalence study and limited sampling modeling. Int J Clin Pharmacol Ther 2002; 40:424-30. [PMID: 12358160 DOI: 10.5414/cpp40424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES To assess the bioequivalence of 2 formulations of carbamazepine and to develop and validate limited sampling strategy (LSS) models for estimating the area under the plasma concentration-time curve (AUC0-infinity) and the peak plasma concentration (Cmax) of carbamazepine. METHODS Twenty-four (12 men, 12 women) healthy volunteers received single oral doses (400 mg) of carbamazepine, as reference and test conventional-release formulations, in a standard 2-sequence, 2-period crossover design. Bioequivalence assessment was based on the individual ratios of log-transformed values of AUC0-infinity and Cmax LSS modeling was developed in a training set of 12 randomly assigned volunteers and was validated on the other 12 subjects (validation set). RESULTS Carbamazepine AUC0-infinity and Cmax can be accurately predicted (R2 = 0.89 - 0.95, precision = 2.6 - 7.2%) by single-point (72 h) and 2-point LSS models (6, 32 h), respectively. Bioequivalence assessments based on LSS-derived AUC0-infinity and Cmax provided results similar to those obtained using all the concentration-in-plasma data points, and indicated that the 2 formulations are bioequivalent. CONCLUSION One-and 2-point LSS models provided accurate estimates of carbamazepine's AUC0-infinity and Cmax, and allowed correct assessment of bioequivalence between the formulations studied.
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Affiliation(s)
- G Suarez-Kurtz
- Coordenação de Pesquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil.
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27
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Saldiva SRM, Carvalho HB, Castilho VP, Struchiner CJ, Massad E. Malnutrition and susceptibility to enteroparasites: reinfection rates after mass chemotherapy. Paediatr Perinat Epidemiol 2002; 16:166-71. [PMID: 12064270 DOI: 10.1046/j.1365-3016.2002.00402.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The evidence that relates malnutrition to enteroparasite infections arises from studies that demonstrate the improvement of nutritional indicators after antiparasitism treatment. However, the role of malnutrition as an aggravating factor to the susceptibility to enteroparasite infections is still not fully understood. We investigated the correlation between malnutrition and enteroparasite infection after mass chemotherapy, in a poor city of São Paulo State, Brazil. The sample comprised 759 children between 1 and 10 years of age of whom 585 were followed up for a period of 1 year and periodically assessed for reinfection with enteroparasites. One year of follow-up after mass chemotherapy demonstrated that 38 of the undernourished children were reinfected with enteroparasites, as compared with 25 of the eutrophic children (P = 0.033). The survival multivariate analysis demonstrated that, after controlling for the potential confounding variables, maternal literacy and per capita income rate, malnutrition was associated with susceptibility to reinfection (P = 0.13). We demonstrate that, although maternal literacy and per capita income rate are indeed confounding variables, malnutrition contributes to an increase in the risk of enteroparasite infections.
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Affiliation(s)
- S R M Saldiva
- School of Medicine, University of São Paulo, Rio de Janeiro, Brazil
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28
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Brunet RC, Struchiner CJ, Loinaz A. A method for estimating time dependent intervention benefits under arbitrarily varying age and exogenous components of hazard. Lifetime Data Anal 2001; 7:377-392. [PMID: 11763545 DOI: 10.1023/a:1012548815575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A method for estimating the dependence of intrinsic intervention benefits on time elapsed since the intervention took place is proposed. The method is aimed at intervention programs against diseases where one or all of the following components of hazard intensity may undergo important and unknown variations: 1) the intervention benefits to a subject are a function of the time elapsed since the intervention took place, or since inception for a continuing treatment, 2) the subjects vulnerability is an unknown function of their age, 3) the exogenous or environmental baseline intensity, to which all are assumed subjected, fluctuates arbitrarily with calendar time. During the time span of a study, these variables interact in a complex way, possibly masking the real contribution of the intervention. However, with very general assumptions about how hazard components interact, the cumulative hazards of subpopulations treated at different times in the past are shown to be described mathematically by a convolution of the time elapsed dependent intervention benefit function with the age and calendar time dependent baseline intensity. Starting from the cumulative hazards of untreated and treated subpopulations that had the intervention at different times in the past, a method of deconvolution through regularization is proposed to reconstruct the time elapsed dependence of the intervention benefit function. The regularization technique used is of the 'penalized least square smoothing' type, it is applied to the solution of Volterra integral equations of the first kind under noisy inputs. Simulations, to test for the reconstruction of different modes of time elapsed variation of the intervention benefits, are carried out on realistically noisy 'data sets' taken to be available at a limited number of time points. The stability of the estimated reconstructions, to measurement errors, is examined through repeated simulations with random noise added to inputs. The method is applied to a Brazilian data set where BCG vaccination resulted in a small reduction in the cumulated risk of leprosy infection.
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Affiliation(s)
- R C Brunet
- Département de mathématiques et de statistique, Université de Montréal, Montréal, Québec, Canada.
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29
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Suarez-Kurtz G, Ribeiro FM, Estrela RC, Vicente FL, Struchiner CJ. Limited-sampling strategy models for estimating the pharmacokinetic parameters of 4-methylaminoantipyrine, an active metabolite of dipyrone. Braz J Med Biol Res 2001; 34:1475-85. [PMID: 11668360 DOI: 10.1590/s0100-879x2001001100017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bioanalytical data from a bioequivalence study were used to develop limited-sampling strategy (LSS) models for estimating the area under the plasma concentration versus time curve (AUC) and the peak plasma concentration (Cmax) of 4-methylaminoantipyrine (MAA), an active metabolite of dipyrone. Twelve healthy adult male volunteers received single 600 mg oral doses of dipyrone in two formulations at a 7-day interval in a randomized, crossover protocol. Plasma concentrations of MAA (N = 336), measured by HPLC, were used to develop LSS models. Linear regression analysis and a "jack-knife" validation procedure revealed that the AUC(0-infinity) and the Cmax of MAA can be accurately predicted (R2>0.95, bias <1.5%, precision between 3.1 and 8.3%) by LSS models based on two sampling times. Validation tests indicate that the most informative 2-point LSS models developed for one formulation provide good estimates (R2>0.85) of the AUC(0-infinity) or Cmax for the other formulation. LSS models based on three sampling points (1.5, 4 and 24 h), but using different coefficients for AUC(0-infinity) and Cmax, predicted the individual values of both parameters for the enrolled volunteers (R2>0.88, bias = -0.65 and -0.37%, precision = 4.3 and 7.4%) as well as for plasma concentration data sets generated by simulation (R2>0.88, bias = -1.9 and 8.5%, precision = 5.2 and 8.7%). Bioequivalence assessment of the dipyrone formulations based on the 90% confidence interval of log-transformed AUC(0-infinity) and Cmax provided similar results when either the best-estimated or the LSS-derived metrics were used.
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Affiliation(s)
- G Suarez-Kurtz
- Divisão de Farmacologia, Coordenação de Pesquisa, Instituto Nacional de Câncer, CPQ, Praça da Cruz Vermelha, 23, 20130-230 Rio de Janeiro, RJ, Brazil.
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30
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Suarez-Kurtz G, Ribeiro FM, Vicente FL, Struchiner CJ. Development and validation of limited-sampling strategies for predicting amoxicillin pharmacokinetic and pharmacodynamic parameters. Antimicrob Agents Chemother 2001; 45:3029-36. [PMID: 11600352 PMCID: PMC90778 DOI: 10.1128/aac.45.11.3029-3036.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Amoxicillin plasma concentrations (n = 1,152) obtained from 48 healthy subjects in two bioequivalence studies were used to develop limited-sampling strategy (LSS) models for estimating the area under the concentration-time curve (AUC), the maximum concentration of drug in plasma (C(max)), and the time interval of concentration above MIC susceptibility breakpoints in plasma (T>MIC). Each subject received 500-mg amoxicillin, as reference and test capsules or suspensions, and plasma concentrations were measured by a validated microbiological assay. Linear regression analysis and a "jack-knife" procedure revealed that three-point LSS models accurately estimated (R(2), 0.92; precision, <5.8%) the AUC from 0 h to infinity (AUC(0-infinity)) of amoxicillin for the four formulations tested. Validation tests indicated that a three-point LSS model (1, 2, and 5 h) developed for the reference capsule formulation predicts the following accurately (R(2), 0.94 to 0.99): (i) the individual AUC(0-infinity) for the test capsule formulation in the same subjects, (ii) the individual AUC(0-infinity) for both reference and test suspensions in 24 other subjects, and (iii) the average AUC(0-infinity) following single oral doses (250 to 1,000 mg) of various amoxicillin formulations in 11 previously published studies. A linear regression equation was derived, using the same sampling time points of the LSS model for the AUC(0-infinity), but using different coefficients and intercept, for estimating C(max). Bioequivalence assessments based on LSS-derived AUC(0-infinity)'s and C(max)'s provided results similar to those obtained using the original values for these parameters. Finally, two-point LSS models (R(2) = 0.86 to 0.95) were developed for T>MICs of 0.25 or 2.0 microg/ml, which are representative of microorganisms susceptible and resistant to amoxicillin.
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Affiliation(s)
- G Suarez-Kurtz
- Instituto Nacional de Câncer, Coordenação de Pesquisa, Rio de Janeiro, Brazil.
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Abstract
There are many different effects to consider when evaluating vaccines in the field. In this review, we have covered some of the various measures and issues related to study design and interpretation of the different measures. We emphasize that in designing and understanding vaccine studies, it is necessary to be specific about what the effect of interest is and about the assumptions underlying the interpretation of the results. Halloran et al. (81) present design, analysis, and interpretation of vaccine studies in more detail.
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Affiliation(s)
- M E Halloran
- Department of Biostatistics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
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32
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Hofer CB, Harrison LH, Struchiner CJ, Moreira RI, do Lago RF, de Melo MF, Schechter M. Acute retrovirus syndrome among prospectively identified homosexual men with incident HIV infection in Brazil. Projecto Praça Onze Study Group. J Acquir Immune Defic Syndr 2000; 25:188-91. [PMID: 11103050 DOI: 10.1097/00042560-200010010-00014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Symptoms associated with HIV infection are common among HIV seroconverters, but the acute retroviral syndrome (ARS) is a diagnostic challenge because of the absence of a sensitive and specific case definition. We conducted an analysis of HIV seroconverters in Projeto Praça Onze, a HIVNET HIV seroincidence study among homosexual men in Rio de Janeiro. METHODS Information from study subjects enrolled in Projeto Praça Onze who were documented HIV seroconverters were compared with nonseroconverters. At each semiannual study visit, participants were asked about HIV seroconversion symptoms and sexually transmitted diseases (STDs) during the preceding 6 months. All information was collected before the laboratory evaluation. A classification tree analysis was used to identify an ARS case definition, first using clinical information and then after including risk factor data for seroconversion in our cohort. RESULTS As of July 1998, 674 volunteers were enrolled and 34 of these seroconverted; information was available for 33 of these. Among the seroconverters, 11 (34%) denied any symptoms, and 22 (66%) reported one or more symptoms, the most common of which were fever (25% of seroconverters versus 7% of nonseroconverters; p <.01), night sweats (9% versus 2%, respectively; p =.05), incapacitating disease (ID) for >/=3 days (27% versus 7%, respectively; p <.001), and weight loss of >/=2 kg (21% versus 9%, respectively; p =.05). STDs were more common in seroconverters (gonorrhea: 9% versus 1%, respectively; p <.01 and condyloma: 9% versus 3%, respectively; p =. 08). The first case definition was ID for >3 days, fever, pharyngitis, and myalgia (seroconverters, 3 of 32, versus nonseroconverters, 2 of 640). The second case definition was was ID for >3 days, anti-core hepatitis b-positive, and age <21 years (seroconverters: 6 of 32 versus nonseroconverters 4 of 640). The sensitivity and specificity for the first and second case definitions were: 9.4%, 99.4%, and 18.8%, 99.8%, respectively. CONCLUSIONS Among HIV seroconverters, symptoms consistent with ARS were common. We were unable to identify a sensitive case definition that could be used as a screening tool. Although the clinical case definition was not validated, the specificity of our case definitions was high, suggesting that subjects within this HIV risk group who fulfill the case definition should be tested for HIV.
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Affiliation(s)
- C B Hofer
- Infectious Diseases Service, Hospital Universitário Clementino Fraga Filho, Department of Preventive Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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33
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Barbosa MT, Byington MR, Struchiner CJ. [Dynamic models and social networks: a review and reflections on their contribution to understanding the HIV epidemic]. CAD SAUDE PUBLICA 2000; 16:37-51. [PMID: 10904388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Due to certain specificities in the HIV epidemic, its spread has escaped the random transmission pattern of other infectious diseases. Observation of the epidemic has shown that individual behavior - relational patterns among individuals - plays a crucial role in HIV transmission and that strategies to prevent the epidemic's spread should take this factor into account in order to foster efficient allocation of existing resources. Mathematical and statistical models applying the behavioral approach to the epidemic have estimated interactions between groups whose characteristics and behaviors varied. However, such models have been more "post-dictive" than predictive, due to the inadequate representation of social structures in populations through which infectious agents spread. The social network methodology thus came to be applied to the approach to the HIV epidemic. This article discusses alternatives for the application of this methodology to the Brazilian epidemic, considering that sociometric risk networks structure the flow of infectious agents in communities, creating unique opportunities to interrupt their spread.
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Affiliation(s)
- M T Barbosa
- Departamento de Matemática e Estatística, Universidade do Rio de Janeiro, Brasil
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34
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Abstract
BACKGROUND At the present time, in Brazil and other countries in the Americas, the only cases of paralytic poliomyelitis due to poliovirus are caused by vaccine strains. The recognition of possible determinants of vaccine-associated paralytic poliomyelitis (VAPP) by public health surveillance and immunization programmes is relevant to inform the debate on criteria for case definition and vaccination strategies. METHODS A retrospective cohort study based on the cases of acute flaccid paralysis (AFP) reported to the Ministry of Health (MoH) was designed, with the objective of studying cases of VAPP in Brazil between 1989 and 1995. Clinical, laboratory and epidemiological data from 3656 acute flaccid paralysis (AFP) cases, 30 of them diagnosed as VAPP, were analysed. RESULTS An 8.88 risk ratio of VAPP (95% CI : 4.37-18.03) was found when comparing individuals who received oral poliovirus vaccine (OPV) between 4 and 40 days before the onset of paralysis and individuals who did not receive the vaccine within this period. A risk of 1 case/2.39 million first doses and 1 case/13.03 million OPV doses administered was estimated for the general population. CONCLUSIONS Cases of AFP who received OPV between 4 and 40 days before the onset of paralysis and had fever, a prodrome of gastrointestinal symptoms, history of first dose of OPV, isolation of vaccine poliovirus type 2, and young age deserve careful investigation, since they are at increased risk for the condition studied.
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Affiliation(s)
- L H de Oliveira
- Reference Center Hélio Frega, National Health Foundation, Ministry of Health, Brazil
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35
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Abstract
At the present time, the only poliovirus-caused poliomyelitis cases reported in Brazil and other countries of the Americas are of vaccine etiology. It is important for epidemiological surveillance and immunization programs to evaluate the epidemiological profile of cases of vaccine-associated paralytic poliomyelitis (VAPP) in order to establish criteria for case definition and vaccination strategies. To research VAPP in Brazil, 30 cases diagnosed and classified as such by the Ministry of Health between 1989 and 1995 were submitted to a descriptive study of clinical, laboratory, and epidemiological data. In addition, the risk of occurrence of VAPP was estimated in relation to determinants based on a cohort of 3,656 persons with acute flaccid paralysis. Among individuals who had received oral polio vaccine (OPV) from 4 to 40 days before the onset of paralysis, we found a relative risk of 8.88 (95% CI: 4.37-18.03) for VAPP as compared with persons who had not been vaccinated during the same time interval. For individuals who developed VAPP in the period following national vaccination days, the estimated relative risk was 2.94 (95% CI: 1.44-6.00). For the first dose of OPV administered to the general population the estimated risk was 1 case of VAPP for every 2.39 million doses; for total doses of OPV the risk was 1 case in 13.03 million doses. A major share of VAPP cases were related to children affected by prodromes (fever and gastrointestinal signs and/or symptoms), isolation of vaccine poliovirus type 2, paralysis of the lower limbs, and a mean age of 1 year.
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Affiliation(s)
- L H de Oliveira
- Ministry of Health, National Foundation for Health, Professor Hélio Fraga Reference Center, Rio de Janeiro, Brazil
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Barbosa MTS, Byington MRL, Struchiner CJ. Modelos dinâmicos e redes sociais: revisão e reflexões a respeito de sua contribuição para o entendimento da epidemia do HIV. CAD SAUDE PUBLICA 2000. [DOI: 10.1590/s0102-311x2000000700004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Há especificidades na epidemia do HIV que fazem com que sua transmissão fuja à aleatoriedade verificada na transmissão de outras doenças infecciosas. A observação da epidemia tem mostrado que os comportamentos individuais - padrões de relação que os indivíduos mantêm entre si - desempenham papel crucial na transmissão do HIV e que as estratégias de prevenção do crescimento da epidemia devem tomar em conta este fator para a alocação eficiente dos recursos existentes. Modelos matemáticos e estatísticos que utilizam a abordagem compartimental aplicada à epidemia estimavam as interações entre grupos cujas características e comportamentos variavam. Contudo, tais modelos eram mais "pós-ditivos" que preditivos, atribuindo-se isso à representação inadequada da estrutura social das populações pelas quais se disseminam os agentes infecciosos. Assim, passou-se a aplicar a metodologia de redes sociais à abordagem da epidemia do HIV. Este artigo discute alternativas à aplicação desta metodologia à epidemia brasileira, ponderando que as redes sociométricas de risco estruturam o fluxo de agentes infecciosos em comunidades, criando oportunidades ímpares a sua interrupção.
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Suarez-Kurtz G, Vicente FL, Ponte CG, Buy VL, Struchiner CJ. Limited-sampling strategy models for estimating the area under the plasma concentration-time curve for amlodipine. Eur J Clin Pharmacol 1999; 55:651-7. [PMID: 10638394 DOI: 10.1007/s002280050688] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Develop and validate limited-sampling strategy (LSS) models for estimating the area under the plasma concentration versus time curve (AUC) of amlodipine, using data from a bioequivalence study. METHODS Sixteen healthy volunteers received single 5-mg oral doses of amlodipine, as reference or test formulation, at a 14-day interval, in a randomized, crossover protocol. Plasma concentrations of amlodipine (n = 288), measured by mass spectrometry, were used to develop LSS models. RESULTS Linear regression analysis of the AUC0-72 and a "jack-knife" validation procedure revealed that LSS models based on two sampling times (12 h and 48 h) predict accurately (R2 = 0.99; bias < 0.01%; precision = 0.03%) the AUC0-72 of amlodipine for each formulation. Validation tests indicate that the 2-point LSS model developed for the reference formulation predicts accurately (R2 > 0.90): (a) the individual AUC0-72 for the test formulation in the same group of volunteers; (b) the individual AUC0-72 for the same reference formulation in another bioequivalence study in Brazilian volunteers; (c) the average AUC0-72 reported in seven additional international studies performed under protocols similar to the present investigation; (d) the individual AUC0-72 corresponding to concentration data points provided by a first-order compartmental pharmacokinetic model, when the relative values of either the absorption rate (Kabs) or the bioavailability (F) model parameters were set at 0.85 or 0.6, of their respective original values. CONCLUSIONS The 2-point LSS models developed in the current study predict accurately the AUC of amlodipine under a variety of experimental conditions and, thus, may be valuable for exploring the relationships between the pharmacokinetics and pharmacodynamics of this calcium antagonist, at reduced costs of sample acquisition and analysis, and avoiding sampling at "unsociable" hours.
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Affiliation(s)
- G Suarez-Kurtz
- Instituto Nacional de Câncer, Coordenação de Pesquisa, Santa Casa da Misericórdia, Rio de Janeiro, Brazil.
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Struchiner CJ, de Almeida LM, de Azevedo RS, Massad E. Hepatitis A incidence rate estimates from a pilot seroprevalence survey in Rio de Janeiro, Brazil. Int J Epidemiol 1999; 28:776-81. [PMID: 10480710 DOI: 10.1093/ije/28.4.776] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND To assess the impact of water sanitation and sewage disposal, part of a major environmental control programme in Rio de Janeiro, we carried out sero-prevalence studies for Hepatitis A virus (HAV) in three micro-regions in Rio de Janeiro. Each region varied with regard to level of sanitation. We are interested in assessing the discriminating power of age-specific prevalence curves for HAV as a proxy for improvement in sanitation. These curves will serve as baseline information to future planned surveys as the sanitation programme progresses. METHODS Incidence rate curves from prevalence data are estimated parametrically via a Weibull-like survival function, and non-parametrically via maximum likelihood and monotonic splines. Sera collected from children and adults in the three areas are used to detect antibodies against HAV through ELISA. RESULTS We compare baseline incidence curves at the three sites estimated by the three methods. We observe a strong negative correlation between level of sanitation and incidence rates for HAV infection. Incidence estimates yielded by the parametric and non-parametric approaches tend to agree at early ages in the microregion showing the best level of sanitation and to increasingly disagree in the other two. CONCLUSION Our results support the choice of HAV as a sentinel disease that is associated with level of sanitation. We also introduce monotonic splines as a novel non-parametric approach to estimate incidence from prevalence data. This approach outperforms current estimating procedures.
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Brunet RC, Struchiner CJ. A non-parametric method for the reconstruction of age- and time-dependent incidence from the prevalence data of irreversible diseases with differential mortality. Theor Popul Biol 1999; 56:76-90. [PMID: 10438670 DOI: 10.1006/tpbi.1999.1415] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A method is proposed for reconstructing the time and age dependence of incidence rates from successive age-prevalence cross sections taken from the sentinel surveys of irreversible diseases when there is an important difference in mortality between the infected and susceptible subpopulations. The prevalence information at different time-age points is used to generate a surface; the time-age variations along the life line profiles of this surface and the difference in mortality rates are used to reconstruct the time and age dependence of the incidence rate. Past attempts were based on specified parametric forms for the incidence or on the hypothesis of time-invariant forms for the age-prevalence cross sections. The proposed method makes no such assumptions and is thus capable of coping with rapidly evolving prevalence situations. In the simulations carried out, it is found to be resilient to important random noise components added to a prescribed incidence rate input. The method is also tested on a real data set of successive HIV age-prevalence cross sections from Burundi coupled to differential mortality data on HIV(+) and HIV(-) individuals. The often-made assumption that the incidence rate can be written as the product of a calendar time component and an age component is also examined. In this case, a pooling procedure is proposed to estimate the time and the age profiles of the incidence rate using the reconstructed incidence rates at all time-age points.
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Affiliation(s)
- R C Brunet
- Département de Mathématiques et de Statistique and Centre de Recherches Mathématiques, Université de Montréal, Montréal, Quebec, H3C 3J7, Canada.
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de Almeida LM, Azevedo RS, Guimarães AA, Coutinho EDS, Struchiner CJ, Massad E. Detection of antibodies against hepatitis A virus in eluates of blood spotted on filter-paper: a pilot study in Rio de Janeiro, Brazil. Trans R Soc Trop Med Hyg 1999; 93:401-4. [PMID: 10674088 DOI: 10.1016/s0035-9203(99)90133-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The validity of blood spotted on to filter-paper (BSOFP) eluates for the detection of antibodies against hepatitis A virus (HAV) was investigated in 718 individuals (children and adults) during a field study in a small area in Rio de Janeiro State, Brazil. Serum samples were considered the 'gold standard'. BSOFP eluates were analyzed by 2 different techniques: microplate competitive enzyme-linked immunosorbent assay (ELISA) of the whole study group and microparticle enzyme immune assay (MEIA) of a subsample of 59 individuals. For BSOFP eluates by ELISA, sensitivity and specificity were 89.6% (95% CI: 84.7-93.1) and 97.5% (95% CI: 95.6-98.7), respectively. For a seroprevalence of anti-HAV antibodies of 32%, the positive predictive value was 94.5% (95% CI: 90.3-97.0) and the negative predictive value was 95.2% (95% CI: 92.8-96.8). The test efficiency was 95.0% (95% CI: 93.1-96.4). Similar results were found for BSOFP eluates by MEIA. Agreement between the 2 techniques used for BSOFP (ELISA and MEIA) was also high (kappa = 0.93). These results encourage the more widespread application of BSOFP as a means of surveillance for large-scale epidemiological studies for hepatitis A.
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Affiliation(s)
- L M de Almeida
- Núcleo de Estudos de Saúde Coletiva da Universidade Federal do Rio de Janeiro (NESC/UFRJ), Brazil.
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de Matos HJ, Duppre N, Alvim MF, MachadoVieira LM, Sarno EN, Struchiner CJ. [Leprosy epidemiology in a cohort of household contacts in Rio de Janeiro (1987-1991)]. CAD SAUDE PUBLICA 1999; 15:533-42. [PMID: 10502149 DOI: 10.1590/s0102-311x1999000300010] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study aimed to identify factors influencing the development of leprosy (Hansen's disease) in household contacts. A dynamic cohort was analyzed from 1987 to 1991 at the Hansen's Disease Department of the Oswaldo Cruz Foundation in Rio de Janeiro. The incidence rate was 0.01694 person-years of follow-up. Nevertheless, for subjects at the end of the first year of follow-up the incidence rate was 0.06385 (end of second year, 0.03299; end of third year, 0.02370; end of fourth year, 0.018622; and end of observation period, 0.01694). A stepwise multivariate logistic regression model was proposed to study the risk of developing leprosy, including co-prevalent cases, totaling 758 contacts. In the final model, the risk was associated with a negative Mitsuda skin test (OR = 3.093; CI 95% = 1.735-5.514), prior BCG vaccination (OR = 0.3802; CI 95% = 0.2151-0.66719), and multibacillary primary clinical form (OR = 2.547; CI 95% = 1.249-5.192). The results showed that both multibacillary leprosy and specific immune status are significant indicators for developing the disease in a cohort of household contacts.
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Affiliation(s)
- H J de Matos
- Departamento de Informática Médica, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Av. Prof. Manoel de Abreu 148, 20 andar, Rio de Janeiro, RJ 20560-000 Brasil
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Schechter M, Struchiner CJ, Harrison LH. Protease inhibitors as initial therapy for individuals with an intermediate risk of HIV disease progression: is more necessarily better? AIDS 1999; 13:97-102. [PMID: 10207550 DOI: 10.1097/00002030-199901140-00013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare three possible therapeutic strategies for the treatment of patients with an intermediate risk of HIV disease progression. DESIGN Mathematical modeling based on assumptions derived from published data. METHODS A parametric survival model was fitted to empirical data to describe the survival trajectory of untreated individuals. It was assumed that successful treatment decreases the risk of disease progression curing the first year after its introduction by a constant that is dependent on the magnitude of the initial drop in HIV viral load. Thereafter, individual members of the treatment cohort follow different pathways, depending on the duration of the initial response or, in case of virologic failure, the response to a new drug regimen. RESULTS Sub-groups of patients starting therapy with two nucleoside reverse transcriptase inhibitors (NRTI) or two NRTI and a protease inhibitor had the highest instantaneous risk of disease progression at the end of the 5-year follow-up period. Patients who started therapy with two NRTI and a non-NRTI had the lowest likelihood of progression to AIDS or death at 5 years of follow-up. This is because, in the case of the subgroup whose initial treatment included a protease inhibitor, failure rates due to non-adherence to therapy are high and response to salvage therapy is limited by past protease inhibitor experience. CONCLUSIONS Despite the superior virologic potency of the protease inhibitor-containing regimens, in this analysis other strategies performed equally well or even better. In the absence of solid empirical data and until the advent of antiretroviral regimens that are shown to be safe, simple to take, and maximally suppress viral load, caution may be required in selecting the long-term therapy for patients with less advanced HIV disease.
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Affiliation(s)
- M Schechter
- Infectious Diseases Service, Hospital Universitário Clementino Fraga Filho, Rio de Janeiro, Brazil
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Suarez-Kurtz G, Bozza FA, Vicente FL, Ponte CG, Struchiner CJ. Limited-sampling strategy models for itraconazole and hydroxy-itraconazole based on data from a bioequivalence study. Antimicrob Agents Chemother 1999; 43:134-40. [PMID: 9869578 PMCID: PMC89033 DOI: 10.1128/aac.43.1.134] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The extensive interindividual variability in oral bioavailability of itraconazole prompted an assessment of the bioequivalence of two formulations marketed in Brazil, namely, Sporanox (reference) and Traconal (test). Eighteen healthy volunteers received single 200-mg oral doses of each formulation at 2-week intervals in a randomized, crossover protocol. The concentrations of itraconazole and hydroxy-itraconazole in plasma were measured by high-performance liquid chromatography, and the datum points (n = 396) were subsequently used to develop limited-sampling strategy models for estimation of the areas under the curve (AUCs) for both compounds. The 90% confidence intervals for individual percent ratios (test/reference formulations) of the maximum concentration of drug in serum, the AUC from 0 to 48 h and the AUC from time zero to infinity (AUC0-infinity) for itraconazole and hydoxy-itraconazole were below the range of 80 to 125%, suggesting that these formulations are not bioequivalent. Linear regression analysis of the AUC0-infinity against time and a "jackknife" validation procedure revealed that models based on three sampling times accurately predict (R2, >0.98; bias, <3%; precision, 3 to 7%) the AUC0-infinity for each of the four formulation-compound pairs tested. Increasing the number of sampling points to more than three adds little to the accuracy of the estimates of AUC0-infinity. The three-point models developed for the reference formulation were validated retrospectively and were found to predict within 2% the AUC0-infinity reported in previous studies performed under similar protocols. In conclusion, the data in this study indicate (i) that the tested formulations are not bioequivalent when single doses are compared and (ii) that limited-sampling strategy models based on three points predict accurately the AUC0-infinitys for itraconazole and hydroxy-itraconazole and could be a valuable tool in pharmacokinetic and bioequivalence studies of single oral doses of itraconazole.
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Affiliation(s)
- G Suarez-Kurtz
- Instituto Nacional de Câncer, Coordenação de Pesquisa, Programa de Farmacologia, Rio de Janeiro, Brazil.
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Abstract
This paper reports the efficacy results of the randomized, placebo-controlled, field trial of SPf66 malaria vaccine in Costa Marques, Rondonia, Brazil. This region is characterized by the seasonal distribution of Plasmodium falciparum and P. vivax infections, and the recent occupation by migrants from nonendemic areas. A total of 800 individuals of both sexes, ranging in age from seven to 60 years, were included in the study. Of the initial cohort, 572 participants completed the vaccination schedule. Clinical and parasitologic evaluations were obtained by active and passive searches on a periodic basis. The overall protective efficacy against P. falciparum infections was -1.6% (-32.9% to 22.4%), and 14.1% (-17.0% to 36.9%) for the first episode. The overall protective efficacy for P. vivax infections was -19.7% (-44.8% to 1.03%), and -10.8% (-41.1% to 12.8%) for the first episode. No statistical evidence of an overall significant protective effect of SPf66 malaria vaccine against P. falciparum and P. vivax malaria was obtained in this trial.
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Affiliation(s)
- M Urdaneta
- Escola Nacional de Saude Publica, Fundacao Oswaldo Cruz, Rio de Janeiro, Brazil
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Abstract
Vaccine efficacy and effectiveness (VE) are generally measured as 1 minus some measure of relative risk (RR) in the vaccinated group compared with the unvaccinated group (VE = 1 - RR). In designing a study to evaluate vaccination, the type of effect and the question of interest determine the appropriate choice of comparison population and parameter. Possible questions of interest include that of the biologic effect of vaccination on susceptibility, on infectiousness, or on progression to disease in individuals. The indirect effects, total effects, and overall public health benefits of widespread vaccination of individuals within the context of a vaccination program might also be of primary concern. The change in behavior induced by belief in the protective effects of vaccination might influence the estimates of these effects or might itself be of interest. In this paper, the authors present a framework of study designs that relates the scientific question of interest to the choice of comparison groups, the unit of observation, the level of information available for analysis, and the parameter of effect.
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Affiliation(s)
- M E Halloran
- Department of Biostatistics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
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Werneck GL, Struchiner CJ. Estudos de agregados de doenças no espaço-tempo: conceitos, técnicas e desafios. CAD SAUDE PUBLICA 1997. [DOI: 10.1590/s1413-8123199800020001000044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
Health intervention control programs, such as vaccination, can be evaluated by comparing incidence rates of infection between unprotected and protected individuals in a population. The ratio of incidence rates is usually estimated by following up control and treated groups in order to collect information on person-time and cases in each group. This approach can be expensive and time consuming. An alternative approach is to use prevalence data to reconstitute incidence. Current-status are readily available or easily gathered and can be used to estimate incidence rates. Under certain assumptions of irreversibility for the outcome of interest, we discuss a simple transmission model appropriate to evaluate health interventions that confer long term protection. Rates and populations are parameter-free functions of age and calendar time. We develop general mathematical relationships that link incidence and intervention rates to prevalence which could be estimated from sampling without requiring knowledge of subpopulation demographics.
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Affiliation(s)
- R C Brunet
- Département de Mathématiques et de Statistique, Université de Montréal, Montréal, Quebec, H3C 3J7, Canada
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Abstract
The frequency and description of side effects secondary to the subcutaneous application of SPf66 malaria vaccine and placebo are reported for each dose of application in the participants of the vaccine efficacy trial in Brazil. Side effects evaluated two hours after each application were detected in 8.0%, 30.2% and 8.8%, for the 1st, 2nd and 3rd dose, respectively, in the SPf66 group, and in 7.0%, 8.5% and 2.9% in the placebo group. Local reactions such as mild inflammation, nodule and pain or erythema frequently accompanied by pruritus were the most common reactions detected in both groups (3.8%, 29.1% and 8.5% in the SPf66 group and 4.0%, 7.6% and 2.5% in the placebo group). Among vaccinees, local side effects after the 2nd dose were more frequent in females. Systemic side effects were expressed mainly through general symptoms referred by the participants and were most frequent after the 1st dose in both groups (4.3% in the SPf66 group and 3.0% in the placebo group). Muscle aches and fever were referred by few participants. No severe adverse reactions were detected for either dose of application or group.
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Affiliation(s)
- M Urdaneta
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
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Abstract
The authors consider estimability and interpretation of vaccine efficacy based on time to event data, allowing that some of the population might have a very low probability of acquiring disease, and the rest have partial, possibly continuously distributed, susceptibility. The efficacy parameters of interest in the frailty mixing model include the fraction highly unlikely to acquire the infection or disease due to the vaccine, the degree of partial protection in those still susceptible, and the average protection or summary measure of efficacy under heterogeneity. The efficacy estimates can still be usefully interpreted when the heterogeneity results from heterogeneity in contact patterns, contact rates, or infectiousness of the contacts, as long as these are equal in the vaccinated and unvaccinated groups. A likelihood-based method allows estimation of the efficacy parameters of interest from grouped time to event data. Simulated vaccine studies assuming different levels and distributions of efficacy demonstrate that ignoring heterogeneity in susceptibility or exposure to infection generally results in underestimation of vaccine efficacy as well as incorrect interpretation of the estimates. The approach is also applicable to other covariates affecting susceptibility or exposure to infection in infectious diseases. Exploitation of the dependent happening structure of infectious diseases to obtain a shape for the baseline hazard may help identifiability. The authors recommend fitting several models to time to event data in vaccine studies.
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Affiliation(s)
- M E Halloran
- Department of Biostatistics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
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Urdaneta M, Prata A, Struchiner CJ, Tosta CE, Tauil P, Boulos M. SPf66 vaccine trial in Brazil: conceptual framework study design and analytical approach. Rev Soc Bras Med Trop 1996; 29:259-69. [PMID: 8701046 DOI: 10.1590/s0037-86821996000300007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
This paper describes the study population and the study design of the phase III field trail of the SPf66 vaccine in Brazil. Assessment of validity and precision principles necessary for the appropriate evaluation of the protective effect of the vaccine are discussed, as well as the results of the preliminary analyses of the gathered data. The analytical approach for the estimation of the protective effect of the vaccine is presented. This paper provides the conceptual framework for future publications.
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Affiliation(s)
- M Urdaneta
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Faculdade de Medicina do Triângulo Mineiro, Uberaba, Minas Gerais
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