Replication competent retrovirus testing (RCR) in the National Gene Vector Biorepository: No evidence of RCR in 1,595 post-treatment peripheral blood samples obtained from 60 clinical trials.

The clinical impact of any therapy requires the product be safe and effective. Gammaretroviral vectors pose several unique risks, including inadvertent exposure to replication competent retrovirus (RCR) that can arise during vector manufacture. The US FDA has required patient monitoring for RCR, and the National Gene Vector Biorepository is an NIH resource that has assisted eligible investigators in meeting this requirement. To date, we have found no evidence of RCR in 338 pre-treatment and 1,595 post-treatment blood samples from 737 patients associated with 60 clinical trials. Most samples (75%) were obtained within 1 year of treatment, and samples as far out as 9 years after treatment were analyzed. The majority of trials (93%) were cancer immunotherapy, and 90% of the trials used vector products produced with the PG13 packaging cell line. The data presented here provide further evidence that current manufacturing methods generate RCR-free products and support the overall safety profile of retroviral gene therapy.

Real-world outcomes of a clinical decision support system for diabetic retinopathy in Spain.

Objective: The aim of present study was to evaluate our clinical decision support system (CDSS) for predicting risk of diabetic retinopathy (DR). We selected randomly a real population of patients with type 2 diabetes (T2DM) who were attending our screening programme. Methods and analysis: The sample size was 602 patients with T2DM randomly selected from those who attended the DR screening programme. The algorithm developed uses nine risk factors: current age, sex, body mass index (BMI), duration and treatment of diabetes mellitus (DM), arterial hypertension, Glicated hemoglobine (HbA1c), urine-albumin ratio and glomerular filtration. Results: The mean current age of 67.03±10.91, and 272 were male (53.2%), and DM duration was 10.12±6.4 years, 222 had DR (35.8%). The CDSS was employed for 1 year. The prediction algorithm that the CDSS uses included nine risk factors: current age, sex, BMI, DM duration and treatment, arterial hypertension, HbA1c, urine-albumin ratio and glomerular filtration. The area under the curve (AUC) for predicting the presence of any DR achieved a value of 0.9884, the sensitivity of 98.21%, specificity of 99.21%, positive predictive value of 98.65%, negative predictive value of 98.95%, α error of 0.0079 and ß error of 0.0179. Conclusion: Our CDSS for predicting DR was successful when applied to a real population.

Corticosteroid treatment and mortality in mechanically ventilated COVID-19-associated acute respiratory distress syndrome (ARDS) patients: a multicentre cohort study.

BACKGROUND: Some unanswered questions persist regarding the effectiveness of corticosteroids for severe coronavirus disease 2019 (COVID-19) patients. We aimed to assess the clinical effect of corticosteroids on intensive care unit (ICU) mortality among mechanically ventilated COVID-19-associated acute respiratory distress syndrome (ARDS) patients. METHODS: This was a retrospective study of prospectively collected data conducted in 70 ICUs (68 Spanish, one Andorran, one Irish), including mechanically ventilated COVID-19-associated ARDS patients admitted between February 6 and September 20, 2020. Individuals who received corticosteroids for refractory shock were excluded. Patients exposed to corticosteroids at admission were matched with patients without corticosteroids through propensity score matching. Primary outcome was all-cause ICU mortality. Secondary outcomes were to compare in-hospital mortality, ventilator-free days at 28 days, respiratory superinfection and length of stay between patients with corticosteroids and those without corticosteroids. We performed survival analysis accounting for competing risks and subgroup sensitivity analysis. RESULTS: We included 1835 mechanically ventilated COVID-19-associated ARDS, of whom 1117 (60.9%) received corticosteroids. After propensity score matching, ICU mortality did not differ between patients treated with corticosteroids and untreated patients (33.8% vs. 30.9%; p = 0.28). In survival analysis, corticosteroid treatment at ICU admission was associated with short-term survival benefit (HR 0.53; 95% CI 0.39-0.72), although beyond the 17th day of admission, this effect switched and there was an increased ICU mortality (long-term HR 1.68; 95% CI 1.16-2.45). The sensitivity analysis reinforced the results. Subgroups of age < 60 years, severe ARDS and corticosteroids plus tocilizumab could have greatest benefit from corticosteroids as short-term decreased ICU mortality without long-term negative effects were observed. Larger length of stay was observed with corticosteroids among non-survivors both in the ICU and in hospital. There were no significant differences for the remaining secondary outcomes. CONCLUSIONS: Our results suggest that corticosteroid treatment for mechanically ventilated COVID-19-associated ARDS had a biphasic time-dependent effect on ICU mortality. Specific subgroups showed clear effect on improving survival with corticosteroid use. Therefore, further research is required to identify treatment-responsive subgroups among the mechanically ventilated COVID-19-associated ARDS patients.

Health Innovation Laboratories: towards strong Primary Health Care (PHC)in the Federal District of Brasilia. / Laboratórios de inovação em saúde: por uma Atenção Primária à Saúde forte no Distrito Federal, Brasil.

This article emphasizes PHC as a fundamental strategy for the sustainability of the SUS, based on its impact on health indicators. The attributes and requirements for Robust PHC are based on statements from researchers, policy makers and institutions, including the PAHO/WHO Representation in Brazil. The model proposed is the result of discussions with workers, researchers and health managers in Brazil, endorsing the commitments outlined in the Alma Ata Declaration. The article details the methodology of Health Innovation Laboratories used by PAHO/WHO in Brazil to systematize knowledge generated by innovative health experiences, including the Healthy Brasilia Project, an ongoing activity run by the Health Department of the Federal District (DF) of Brasilia, which has made important changes in the healthcare model, with emphasis on the expansion of Family Health Strategy coverage. This article analyzes the results of the Innovation Laboratories in Robust PHC in the FD that will be consolidated in a Case Study. The initiative aims to raise awareness amongst managers and health workers about innovation in health processes and policies that are essential for the sustainability of theSUS, focusing on the exchange of knowledge between peers about relevant initiatives in PHCin Brazil.

O artigo defende a APS como estratégia fundamental para a sustentabilidade do SUS, subsidiado em resultados sobre o impacto da APS nos indicadores de saúde e outras áreas. São apresentados os atributos e requisitos para uma APS Forte, defendidos por pesquisadores, formuladores de políticas e instituições, entre elas a Representação da OPAS/OMS no Brasil. O formato advogado é fruto de discussão realizada com trabalhadores, pesquisadores e gestores de saúde do país, reafirmando os compromissos da Declaração de Alma Ata. O artigo detalha a metodologia de Laboratórios de Inovação em Saúde, utilizada pela OPAS/OMS no Brasil para identificar e sistematizar experiências inovadoras em saúde, incluindo o acompanhamento do Projeto Brasília Saudável, da Secretaria de Saúde do DF, que vem apresentando importantes transformações no modelo de atenção à saúde, com ênfase na ampliação da cobertura da Estratégia Saúde da Família. O artigo resgata e analisa os trabalhos desenvolvidos pelo Laboratório de Inovação em APS Forte no DF até o momento e que serão sistematizados em Estudo de Caso. A iniciativa visa sensibilizar gestores e trabalhadores em saúde para a inovação em processos e políticas de saúde, sendo essencial para a sustentabilidade do SUS, privilegiando troca de conhecimentos entre pares sobre iniciativas adotadas na APS do Brasil.

Laboratórios de inovação em saúde: por uma Atenção Primária à Saúde forte no Distrito Federal, Brasil / Health Innovation Laboratories: towards strong Primary Health Care (PHC)in the Federal District of Brasilia

Resumo O artigo defende a APS como estratégia fundamental para a sustentabilidade do SUS, subsidiado em resultados sobre o impacto da APS nos indicadores de saúde e outras áreas. São apresentados os atributos e requisitos para uma APS Forte, defendidos por pesquisadores, formuladores de políticas e instituições, entre elas a Representação da OPAS/OMS no Brasil. O formato advogado é fruto de discussão realizada com trabalhadores, pesquisadores e gestores de saúde do país, reafirmando os compromissos da Declaração de Alma Ata. O artigo detalha a metodologia de Laboratórios de Inovação em Saúde, utilizada pela OPAS/OMS no Brasil para identificar e sistematizar experiências inovadoras em saúde, incluindo o acompanhamento do Projeto Brasília Saudável, da Secretaria de Saúde do DF, que vem apresentando importantes transformações no modelo de atenção à saúde, com ênfase na ampliação da cobertura da Estratégia Saúde da Família. O artigo resgata e analisa os trabalhos desenvolvidos pelo Laboratório de Inovação em APS Forte no DF até o momento e que serão sistematizados em Estudo de Caso. A iniciativa visa sensibilizar gestores e trabalhadores em saúde para a inovação em processos e políticas de saúde, sendo essencial para a sustentabilidade do SUS, privilegiando troca de conhecimentos entre pares sobre iniciativas adotadas na APS do Brasil.

Abstract This article emphasizes PHC as a fundamental strategy for the sustainability of the SUS, based on its impact on health indicators. The attributes and requirements for Robust PHC are based on statements from researchers, policy makers and institutions, including the PAHO/WHO Representation in Brazil. The model proposed is the result of discussions with workers, researchers and health managers in Brazil, endorsing the commitments outlined in the Alma Ata Declaration. The article details the methodology of Health Innovation Laboratories used by PAHO/WHO in Brazil to systematize knowledge generated by innovative health experiences, including the Healthy Brasilia Project, an ongoing activity run by the Health Department of the Federal District (DF) of Brasilia, which has made important changes in the healthcare model, with emphasis on the expansion of Family Health Strategy coverage. This article analyzes the results of the Innovation Laboratories in Robust PHC in the FD that will be consolidated in a Case Study. The initiative aims to raise awareness amongst managers and health workers about innovation in health processes and policies that are essential for the sustainability of theSUS, focusing on the exchange of knowledge between peers about relevant initiatives in PHCin Brazil.

Glomerular Filtration Rate and/or Ratio of Urine Albumin to Creatinine as Markers for Diabetic Retinopathy: A Ten-Year Follow-Up Study.

AIMS: To determine the relationship between diabetic nephropathy and diabetic retinopathy on a population of type 2 diabetes mellitus patients. METHODS: A prospective ten-year follow-up population-based study. We determined differences between estimated glomerular filtration rate (eGFR) using the chronic kidney disease epidemiology collaboration equation and urine albumin to creatinine ratio. RESULTS: Annual incidence of any-DR was 8.21 ± 0.60% (7.06%-8.92%), sight-threatening diabetic retinopathy (STDR) was 2.65 ± 0.14% (2.48%-2.88%), and diabetic macular edema (DME) was 2.21 ± 0.18% (2%-2.49%). Renal study results were as follows: UACR > 30 mg/g had an annual incidence of 7.02 ± 0.05% (6.97%-7.09%), eGFR < 60 ml/min/1.73 m2 incidence was 5.89 ± 0.12% (5.70%-6.13%). Cox's proportional regression analysis of DR incidence shows that renal function studied by eGFR < 60 ml/min/1.73 m2 was less significant (p = 0.04, HR 1.223, 1.098-1.201) than UACR ≥ 300 mg/g (p < 0.001, HR 1.485, 1.103-1.548). The study of STDR shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.890, 1.267-2.820), UACR ≥ 300 mg/g (p < 0.001, HR 2.448, 1.595-3.757), and DME shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.920, 1.287-2.864) and UACR ≥ 300 mg/g (p < 0.001, HR 2.432, 1.584-3.732). CONCLUSIONS: The UACR has a better association with diabetic retinopathy than the eGFR, although both are important risk factors for diabetic retinopathy.

Differences in incidence of diabetic retinopathy between type 1 and 2 diabetes mellitus: a nine-year follow-up study.

BACKGROUND/AIMS: To determine the incidence of any diabetic retinopathy (any-DR), sight-threatening diabetic retinopathy (STDR) and diabetic macular oedema (DMO) and their risk factors in type 1 diabetes mellitus (T1DM) over a screening programme. METHODS: Nine-year follow-up, prospective population-based study of 366 patients with T1DM and 15 030 with T2DM. Epidemiological risk factors were as follows: current age, age at DM diagnosis, sex, type of DM, duration of DM, arterial hypertension, levels of glycosylated haemoglobin (HbA1c), triglycerides, cholesterol fractions, serum creatinine, estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (UACR). RESULTS: Sum incidence of any-DR was 47.26% with annual incidence 15.16±2.19% in T1DM, and 26.49% with annual incidence 8.13% in T2DM. Sum incidence of STDR was 18.03% with annual incidence 5.77±1.21% in T1DM, and 7.59% with annual incidence 2.64±0.15% in T2DM. Sum incidence of DMO was 8.46% with annual incidence 2.68±038% in patients with T1DM and 6.36% with annual incidence 2.19±0.18% in T2DM. Cox's survival analysis showed that current age and age at diagnosis were risk factors at p<0.001, as high HbA1c levels at p<0.001, LDL cholesterol was significant at p<0.001, eGFR was significant at p<0.001 and UACR at p=0.017. CONCLUSIONS: The incidence of any-DR and STDR was higher in patients with T1DM than those with T2DM. Also, the 47.26% sum incidence of any-DR in patients with T1DM was higher than in a previous study (35.9%), which can be linked to poor metabolic control of DM. Our results suggest that physicians should be encouraged to pay greater attention to treatment protocols for T1DM in patients.

Cost of diabetic retinopathy and macular oedema in a population, an eight year follow up.

BACKGROUND: Prospective, population-based study of an 8-year follow up. To determine the direct cost of diabetic retinopathy [DR], evaluating our screening programme and the cost of treating DR, focusing on diabetic macular oedema [DMO] after anti-vascular endothelial growth factor [anti-VEGF] treatment. METHODS: A total of 15,396 diabetes mellitus [DM] patients were studied. We determined the cost-effectiveness of our screening programme against an annual programme by applying the Markov simulation model. We also compared the cost-effectiveness of anti-VEGF treatment to laser treatment for screened patients with DMO. RESULTS: The cost of our 2.5-year screening programme was as follows: per patient with any-DR, €482.85 ± 35.14; per sight-threatening diabetic retinopathy [STDR] patient, €1528.26 ± 114.94; and €1826.98 ± 108.26 per DMO patient. Comparatively, an annual screening programme would result in increases as follows: 0.77 in QALY per patient with any-DR and 0.6 and 0.44 per patient with STDR or DMO, respectively, with an incremental cost-effective ratio [ICER] of €1096.88 for any-DR, €4571.2 for STDR and €7443.28 per DMO patient. Regarding diagnosis and treatment, the mean annual total cost per patient with DMO was €777.09 ± 49.45 for the laser treated group and €7153.62 ± 212.15 for the anti-VEGF group, with a QALY gain of 0.21, the yearly mean cost was €7153.62 ± 212.15 per patient, and the ICER was €30,361. CONCLUSIONS: Screening for diabetic retinopathy every 2.5 years is cost-effective, but should be adjusted to a patient's personal risk factors. Treatment with anti-VEGF for DMO has increased costs, but the cost-utility increases to 0.21 QALY per patient.

Programa Mais Médicos: uma avaliação dos resultados iniciais referentes ao eixo do provimento emergencial a partir da Teoria da Avaliação de Programas

O Programa Mais Médicos (PMM) tem como meta central atingir o índice de 2,7 médicos/1.000 habitantes no ano de 2026 e, para isso, seu principal eixo de ação consiste em ampliar equitativamente o número de vagas e cursos de graduação e de residência médica. No entanto, para combater a escassez e a distribuição desigual de médicos de forma imediata, o PMM possui outro eixo de ação: o do provimento mergencial. Por intermédio da chamada de profissionais brasileiros e estrangeiros o governo federal visa prover médicos para os municípios e áreas do país com os perfis de maior vulnerabilidade social. O presente trabalho objetiva avaliar os resultados iniciais (outputs) referentes ao eixo do provimento emergencial do Programa Mais Médicos a partir da Teoria da Avaliação de Programas (Program Evaluation Theory). Foram realizadas análises estatísticas dos dados oriundos do Sistema de Gerenciamento de Projetos (SGP) e do Histórico de Cobertura da Saúde da Família (HCSF), no intuito de averiguar se os médicos foram lotados nas regiões prioritárias e quais foram os efeitos causados na cobertura populacional da Estratégia Saúde da Família (ESF). Observou-se que 73% dos municípios brasileiros receberam ao menos um médico do Programa, sendo que entre 65 a 83% dos médicos foram alocados em municípios com perfil prioritário, a depender dos critérios utilizados na análise. Além disso, 82% dos médicos foram lotados na ESF, culminando em uma expansão de 15,7% na população coberta nos dois anos de duração do Programa, com percentuais variando de 10 a 25% entre as regiões geográficas. Amparado pelos referencial da Teoria da Avaliação de Programas e pelos resultados demonstrados na análise estatística dos dados, constata-se que o eixo do provimento emergencial está logrando êxito ao privilegiar as áreas mais vulneráveis do país.

The central goal of the More Doctors Program (MDP) is to achieve 2.7 doctors/1,000inhabitants by 2026, and to do so its main objective relies on creating new residencyvacancies and programmes during this period. However, a more immediate strategytackle both the shortage and the uneven distribution of doctors, is the emergencyprovision of doctors. The Brazilian federal government made an open call for bothBrazilian and foreign doctors to work in areas with the country´s worst record of socialvulnerability. This study evaluates the emergency provision using Program EvaluationTheory. Statistical analyses were conducted on secondary data from two differentsources: Project Management System (Sistema de Gerenciamento de Projetos – SGP)and Longitudinal Family Health Strategy Coverage Data (Historico de Cobertura daSaude da Familia – HCSF), in order to confirm if the doctors were, indeed, placed inthe prioritized areas, and the effects on the coverage Family Health Strategy (FHS).Approximately 73% of the Brazilian municipalities received at least one MDP doctor.From 65% to 83% of the doctors were placed in the prioritized municipalities,depending on the criteria adopted. Around 82% were working within the FHS, for whichthere was an increase of 15.7% in the FHS coverage in two years. Among the Brazilianregions, the percentage varied from 10% to 25%. Based on Program EvaluationTheory, this study found that the emergency provision is succeeding at reaching themost vulnerable areas of the country. As for FHS coverage, despite these conclusivefindings, more research is needed, in particular longitudinal research, to ascertainwhether there is a causal link with the MDP.

Changes observed in diabetic retinopathy: eight-year follow-up of a Spanish population.

BACKGROUND/AIMS: To determine the changes in the incidence of diabetic retinopathy (DR), diabetic macular oedema (DMO) and their risk factors in a population-based study of patients with diabetes mellitus (DM) referred to our 16 Primary Health Care Areas (HCAs). METHODS: Prospective population-based study of a total of 15 396 Caucasian patients with DM, who represent 86.53% of the total patients with DM in our HCAs, were studied over an 8-year follow-up period. All patients were screened with a mean follow-up of 3.18±1.11 times for each patient over the 8 years. RESULTS: The yearly mean value of any DR was 8.37±2.19% (8.09%-8.99%); of advanced DR yearly mean value of 0.46±0.22% (0.03-0.78); and of DMO a yearly mean value of 2.19±0.18% (2%-2.49%). A clear increase was observed in the last 3 years, any DR increased from 8.09% in 2007 to 8.99% in 2014, and DMO from 2% in 2007 to 2.49% in 2014. These increases were more evident in some age groups. For patients with any DR aged 41-50 and 51-60 and for patients with advanced DR aged 41-50, 51-60 and 61-70, the increase was more marked, related to an increase in HbA1c values or to patients treated with insulin. CONCLUSIONS: An increase in the incidence of DR and DMO was observed, especially in the younger patients aged between 31 and 70 years. This is linked to bad metabolic control of DM. Our results suggest a greater number of ocular complications in the near future, such as neovascular glaucoma, if these current findings are not addressed.

Controle de papuã (Urochloa plantaginea) e produtividade de milho em solo argiloso através de formulação e doses de atrazina com liberação controlada / Control of alexandergrass and maize yield in a clay soil through concentrations and controlled release formulation and doses of atrazine

A utilização de herbicidas com formulações com liberação controlada poderá se constituir em uma ferramenta importante para reduzir problemas de lixiviação e garantir a eficácia desses produtos. O objetivo do presente trabalho foi comparar a eficiência de controle de Urochloa plantaginea (UROPL) e o rendimento de grãos de milho entre uma formulação de atrazina comercial (WG) e uma formulação de liberação controlada (xerogel). O delineamento utilizado foi o de blocos ao acaso, em parcelas subdivididas, com quatro repetições, em um esquema (2x7)+1. Nas parcelas principais, foram locadas as formulações de atrazina (WG e xerogel) e, nas subparcelas, as concentrações dos herbicidas (0, 2400, 3200, 3600, 4200, 5400 e 8000g de atrazina ha-1). Foram determinados os níveis de controle e densidade de plantas de UROPL e o rendimento de grãos da cultura do milho. A elevação das doses de atrazina resultou em aumento dos níveis de controle de UROPL. Em avaliações realizadas aos 28 e 35 dias após a aplicação, a atrazina xerogel demonstrou eficiência agronômica superior à formulação WG. Não ocorreram diferenças de rendimento de grãos de milho em parcelas tratadas com diferentes formulações e níveis de atrazina.

The use of herbicides with controlled release formulations may constitute important tool to reduce leaching problems and increase the efficacy of atrazine in soil. The aim of this study was to compare the efficiency of control of Urochloa plantaginea (UROPL) and corn grain yield from a commercial formulation (WG) of atrazine and a controlled-release formulation (xerogel). The design was randomized blocks in split plots with four replications in a scheme (2x7)+1. Factor A consisted of the formulations of atrazine (WG and xerogel), factor B concentrations of herbicide (0, 2400, 3200, 3600, 4200, 5400 and 8000ha atrazine g-1). Variables assessed consisted of control levels, plant density of UROPL and corn grain yield. The increasing levels of atrazine resulted in increased levels of control UROPL. In assessments made at 28 and 35 days after application, atrazine xerogel showed higher agronomic efficiency than the WG formulation. There were no differences in corn grain yield from plots treated with different formulations and atrazine levels.

Learning from the Brazilian community health worker model in North Wales.

Health policymakers in many countries are looking at ways of increasing health care coverage by scaling up the deployment of community health workers. In this commentary, we describe the rationale for the UK to learn from Brazil's scaled-up Community Health Worker primary care strategy, starting with a pilot project in North Wales.

Culturas resistentes aos herbicidas inibidores da enzima ALS: revisão de literatura / Crops resistant to ALS herbicide: a review

O objetivo desta revisão de literatura foi abordar os principais aspectos genéticos e as técnicas empregadas no desenvolvimento de culturas resistentes aos herbicidas inibidores da enzima ALS,bem como seus impactos na agricultura. O principal fator limitante a elevados níveis de produtividade das culturas é a interferência com as plantas daninhas. O melhoramento genético e técnicas de engenharia genética permitiram desenvolver culturas resistentes aos herbicidas. Estas culturas constituem estratégias de manejo para obtenção de alta produtividade de alimentos para suprir a elevada demanda global para os próximos anos. Como os inibidores da enzima ALS foram os pioneiros no Brasil a terem culturas resistentes e por ser o grupo de herbicidas mais utilizados no país, a análise da situação de culturas resistentes a esses produtos serve de modelo para entender os benefícios e os riscos associados à utilização de culturas resistentes aos herbicidas.

Seleção de espécies bioindicadoras para uso em bioensaios de lixiviação e persistência de Atrazina no solo / Selection of bioindicators for use on leaching and persistence of Atrazine in soil bioassays

Este experimento teve por objetivo selecionar espécies cultivadas com potencial para utilização como bioindicadoras da presença de atrazina em ensaios de persistência e lixiviação. Adotou-se delineamento inteiramente casualizado, com quatro repetições, em bifatorial 5 x 6, sendo o fator A constituído pelas concentrações de atrazina com formulação WG (0, 150, 300, 600, 1200 g atrazina ha-1) e o fator B pelas espécies bioindicadoras: aveia branca, trigo, quiabo, tomate, ervilha e rabanete. Aplicou-se o herbicida atrazina em pré-emergência das espécies em solo argiloso. Realizaram-se quatro avaliações de estatura de planta, injúria e no fi nal do experimento foram determinadas as matérias verde e seca das partes aéreas. De forma geral, o experimento permitiu classifi car as espécies conforme seu nível de sensibilidade à atrazina: quiabo e ervilha evidenciaram pequena sensibilidade; aveia e trigo revelaram nível intermediário de sensibilidade, enquanto que o tomate e o rabanete apresentaram o mais alto nível de sensibilidade.

Herbicides resistant weed management using sensitivity analysis of the weed population growth curve

Strategies to prevent herbicide weed resistance are rarely practiced by farmers. As a consequence, herbicide resistant weed biotypes (HRWB) have been increasing worldwide in the past decades. This paper aims to analyze the weed population growth curve and to propose a strategic plan for prevention and management of HRWB. The existing weed control methods are organized considering the sensitivity analysis of the population growth at each phase of the logistic growth curve. This analysis indicates that tactics directed to reduce the population growth rate are most appropriate for HRWB management,mainly at the initial phase of the resistant weed population growth. This epidemiological approach provides evidence to the importance of early detection and management of HRWB.

Nível de dano econômico aplicado a herbologia: revisão / Economic threshold applied to weed science-review

Esta revisão de literatura teve como objetivo abordar a aplicação do nível de dano econômico (NDE) no manejo de plantas daninhas. Foram discutidos os motivos para o desenvolvimento dessa relação econômica, a função do NDE como critério de decisão do controle no manejo integrado de plantas daninhas, a teoria da sua aplicação e a magnitude dos seus valores para o manejo dessas plantas, bem como as limitações e perspectivas da sua aplicação na Herbologia. O desenvolvimento de herbicidas seletivos de aplicação em pós-emergência da cultura possibilitou a adaptação do conceito do NDE para o manejo de plantas daninhas. Com isso, esse nível de dano tornou-se um dos principais fundamentos teóricos do manejo integrado, por auxiliar na tomada de decisão do controle dessas espécies nas áreas agrícolas. Na prática, o NDE é pouco utilizado no manejo de plantas daninhas por cinco motivos: (i) as relações de interferência foram desenvolvidas para organismos consumidores e produtores; (ii) ocorrência natural de populações poliespecíficas de plantas daninhas nas áreas agrícolas; (iii) falta de estabilidade das variáveis biológicas e econômicas utilizadas na sua estimativa; (iv) irrelevância do parâmetro obtido para culturas com baixa habilidade competitiva; e (v) consequências ecológicas a médio e longo prazo advindas do seu uso para o agroecossistema. Estratégias alternativas aos níveis de dano, como os programas computacionais, devem ser desenvolvidas para mediar as decisões de controle das plantas daninhas.

Interferência e nível de dano econômico de Brachiaria plantaginea e Ipomoea nil na cultura do feijão comum / Interference and economic threshold of Brachiaria plantaginea and Ipomoea nil in the common bean crop

As pesquisas acerca do impacto da interferência das plantas daninhas sobre as culturas normalmente são realizadas com uma única espécie infestante, quando na realidade podem ocorrer diversas. Os objetivos deste trabalho foram avaliar a interferência de Brachiaria plantaginea e Ipomoea nil sobre o rendimento de grãos do feijoeiro (Phaseolus vulgaris) e determinar o nível de dano econômico (NDE) de cada espécie na cultura. Foram realizados dois experimentos a campo com as cultivares de feijão 'IPR Graúna' (Grupo Preto) e 'UTF-06' (Grupo Carioca) em convivência com infestações mistas em diferentes proporções aleatórias das espécies B. plantaginea e I. nil. Modelos de regressão múltiplos foram utilizados para determinar a capacidade de interferência de cada espécie daninha sobre a produtividade da cultura. O impacto de interferência de cada planta de I. nil correspondeu a 2,6 e 0,25 quando comparada a cada planta de B. plantaginea, dependente das proporções relativas na comunidade infestante e das condições de cada experimento. A cultivar 'IPR Graúna' apresentou maior habilidade competitiva do que 'UTF-06'. O NDE foi dependente da proporção relativa de cada espécie daninha na comunidade e foi obtido sob baixas infestações (<16 plantas m-2) em todas as condições testadas e simuladas.

The researches about the impact of weed interference on crops are usually performed with a single weed species, when in reality there are numerous. The objective of this study was to evaluate the interference of Brachiaria plantaginea and Ipomoea nil on the grain yield of French beans (Phaseolus vulgaris) and to determine the economic weed threshold (EWT) of each species on the crop. Two field experiments were conducted with bean cultivars 'IPR Graúna' (Black group) and 'UTF-06' (Carioca group) in coexistence with random proportions of mixed infestations of B. plantaginea and I. nil. Multiple regression models were used to determine the interference abi1lity of each weed species on crop productivity. The interference ability of each plant of I. nil corresponded to 2.6 and 0.25 of each B. plantaginea, dependent on the relative proportions on the weed community and on the conditions of each experiment. Cultivar 'IPR Graúna' showed higher competitive ability than 'UTF-06'. The EWT was dependent on the relative proportion of each weed species in the community and was reached under low infestation (<16 plants m-2) in all conditions tested and simulated.

Seleção de plantas quantificadoras de herbicidas residuais / Selection of residual herbicides quantifying plants

A determinação da concentração de compostos no solo por meio de plantas quantificadoras apresenta como principal vantagem detectar somente resíduos biologicamente ativos, não havendo necessidade de instrumentos onerosos e de prévia extração dos resíduos do solo. Dessa forma, este trabalho teve como objetivo, selecionar plantas quantificadoras da presença de herbicidas residuais (pré emergentes) para o uso em bioensaios. Utilizou-se delineamento experimental completamente casualizado com arranjo bifatorial 8x6, com cinco repetições. O fator A consistiu de espécies cultiváveis e o fator B de herbicidas aplicados em pré emergência. Os resultados evidenciaram que a sensibilidade na detecção do herbicida no solo depende da espécie utilizada. A sensibilidade das espécies Lactuca sativa L. e Raphanus sativus var. sativus L. não permitiu condições de quantificar a presença dos herbicidas atrazina, cloransulam, imazaquin, metribuzin e S-metolacloro. Plantas de Curcubita pepo L. são promissoras na bioavaliação de metribuzin. A espécie Cucumis sativus L. mostrou-se potencial biondicadora de cloransulan e imazaquin. Avena sativa L. apresentou-se como potencial quantificadora de imazaquin e metribuzin, Hordeum vulgare L. pode quantificar o metribuzin e Triticum aestivum L. é promissor na detecção da biodisponibilidade de atrazina.

Biologia e ecofisiologia de buva (Conyza bonariensis e Conyza canadensis): [revisão] / Biology and ecophysiology of hairy fleabane (Conyza bonariensis) and horseweed (Conyza canadensis)

Conyza bonariensis (L.) Cronquist e Conyza canadensis (L.) Cronquist são duas espécies de plantas daninhas pertencentes à família Asteraceae. Com freqüência, elas infestam pomares, vinhedos e outras culturas, como milho, soja e algodão e, também, culturas forrageiras, pastagens e áreas não-cultivadas. Esta revisão de literatura tem por objetivos descrever e discutir as características botânicas, biológicas e ecofisiológicas daquelas espécies com a finalidade de facilitar a adoção de estratégias para seu manejo em culturas ou limitar seu estabelecimento. Conyza canadensis é uma espécie anual ou bienal, nativa da América do Norte, enquanto C. bonariensis é uma espécie anual, nativa da América do Sul. A propagação destas espécies dá-se através de sementes que são facilmente dispersas através do vento e da água. As sementes não apresentam dormência e podem germinar prontamente em condições de temperatura e umidade favoráveis. Em vários países, inclusive no Brasil, foi constatada resistência aos herbicidas em biótipos destas espécies. Adoção de práticas culturais diversificadas, integradas ao controle químico, pode minimizar os efeitos negativos provocados por buva e, também, prevenir casos de resistência.

Conyza bonariensis (L.) Cronquist and Conyza canadensis (L.) Cronquist are two weed species belonging to Asteraceae family. Frequently, they occur in orchards, vineyards, and in other crops, such as corn, soybean, and cotton and, also, in forage crops and pastures, as well as in fallow areas. This literature review has as objectives to describe and discuss botanical, biological, and ecopysiological characteristics of Conyza species that may facilitate adoption of strategies for their management in crops or to limit their establishment. Conyza canadensis is an annual or biennial species, native of North America; whereas, C. bonariensis is an annual species, native of South America. Spreading of both species occurs by seeds, which are easily dispersed through wind and water. Seeds do not present dormancy and can germinate promptly under favorable conditions of temperature and humidity. In various countries, including Brazil, Conyza biotypes resistant to herbicides were found. Adoption of diversified cultural practices, integrated to were found chemical control, may minimize the negative effects of Conyza, as well as, prevent cases of resistance.

Eficácia do herbicida acetochlor na semeadura direta e convencional com ou sem palha e os efeitos sobre o rendimento do milho / Acetochlor herbicide efficacy on tillage and no-tillage systems on straw mulch presence or absence and effect on corn yield

O experimento foi conduzido na Faculdade de Agronomia da Universidade Federal do Rio Grande do Sul, ano agrícola de 2000/2001, com o objetivo de avaliar a eficácia de controle das plantas daninhas com o herbicida acetochlor em Argissolo Vermelho, conduzido sob semeadura direta e preparo convencional, na presença ou ausência de palha. O delineamento experimental utilizado foi blocos casualizados com quatro repetições. Os tratamentos constaram de acetochlor nas doses de 0, 1680, 3360 e 5040g ha-1, aplicado em solo sob semeadura direta e preparo convencional, na presença (4,5t ha-1) ou ausência de palha de aveia. Foram avaliados o controle das plantas daninhas, além da altura de plantas e rendimento de grãos de milho. O acetochlor foi mais eficiente para o controle das plantas daninhas no preparo convencional, comparado à semeadura direta. A palha reduziu a eficácia de controle pelo acetochlor. A altura das plantas de milho foi maior na semeadura direta. O rendimento de grãos de milho foi maior no preparo convencional e na presença da palha devido ao melhor controle das plantas daninhas.