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1.
Psicol. educ ; (41): 37-49, dic. 2015. ilus, tab
Article in Portuguese | LILACS | ID: lil-782717

ABSTRACT

Este artigo tem como objetivo analisar se as estratégias de aprendizagem autorregulatórias desenvolvidas em uma prática de ensino reflexiva contribuíram para a formação de alunos autorregulados e possibilitaram a promoção de avanços na aprendizagem de alunos do ensino superior relativas à escrita de um artigo científico. A prática de ensino reflexiva desenvolveu-se durante seis encontros nos quais buscou-se perceber a tomada de consciência, o controle e a gestão do aluno em seu processo de aprendizagem. Iniciou-se a pesquisa com a aplicação do questionário CEA (Conhecimento de Estratégias Autorregulatórias), seguido das "Oficinas de desenvolvimento de estratégias autorregulatórias da aprendizagem" as quais tiveram como objetivo principal, para os sujeitos pesquisados, aprender estratégias para a escrita de artigos científicos e, para a pesquisadora, analisar se as estratégias utilizadas nessa prática reflexiva promoveriam a autorregulação para a escrita de artigos científicos. Ao final dos encontros, após seis meses da intervenção, aplicou-se novamente o questionário CEA em uma entrevista semiestruturada. Da análise dos dados, emergiram duas categorias: 1) Estratégias Cognitivas e Metacognitivas; 2) Estratégias Motivacionais; que articuladas entre si contribuem significativamente para a formação de um aluno autorregulado. Conclui-se que os dados reforçam a importância do conhecimento de estratégias autorregulatórias nos processos de aprendizagem, a fim de que o aluno universitário seja capaz de atingir seus objetivos diante das tarefas, promovendo uma consciência reflexiva.


This article aims to examine whether self-regulatory learning strategies developed in a practice of reflective teaching contributed to the formation of self-regulated learners and enabled the promotion of advances in the learning of a group of students in higher education to support them in a scientific article production. The practice of reflective teaching, developed during six meetings, found if the student showed awareness, control and management of their learning process. We started the research with the questionnaire CEA (Knowledge of self-regulatory strategies), followed by six "Workshops for development of self-regulatory learning strategies". These meetings mainly aimed for those individuals surveyed, learn strategies for writing papers and for the researcher to analyze the strategies used in this reflective practice in higher education, would promote self-regulation by stimulating the processes students learn college. At the end of the meetings, 6 months after the intervention was applied CEA questionnaire and a semi-structured interview. From the data analysis, two categories emerged: 1) Cognitive and Metacognitive Strategies; 2) Motivational Strategies; that articulated between them indicate that contributed significantly to the formation of the self-regulated learner. We conclude that the data support the importance of the knowledge of self-regulatory strategies in the learning process, so that the university student is able to achieve their goals in tasks, promoting a reflective consciousness.


Este artículo tiene como objetivo analizar si las estrategias de aprendizaje, de autorregulación desarrolladas en la práctica de la enseñanza reflexiva, contribuyeron a formación de estudiantes autorregulados y permitieron la promoción de los avances en la aprendizaje de un grupo de estudiantes de educación superior para la producción de un artículo científico. La práctica de la enseñanza reflexiva se desarrolló durante seis reuniones: pesquisó, a partir de las estrategias de aprendizaje de autorregulación, si estudiante mostro conciencia, control y gestión de su proceso de aprendizaje. Comenzó la investigación con la aplicación del cuestionario CEA (Conocimiento de Estrategias de Autorregulación), seguido de seis "Talleres de desarrollo de estrategias de autorregulación de la aprendizaje" como objetivo principal, para los sujetos, aprender estrategias para escribir artículos científicos y, para el investigador , analizar si las estrategias utilizadas en esta práctica reflexiva, promueven la autorregulación mediante la estimulación de los procesos de aprendizaje de los estudiantes de la universidad. Seis meses después de la intervención, se aplicó de nuevo cuestionario CEA y una entrevista semi-estructurada. Del análisis de datos, emergieron categorías: 1) Estrategias cognitivas y metacognitivas; 2) Estrategias de motivación. Os datos apoyan la importancia del conocimiento de las estrategias de autorregulación en el proceso de aprendizaje, por lo que el estudiante universitario es capaz de alcanzar sus objetivos en las tareas, con promoción de una conciencia reflexiva.

2.
Psicol. educ ; (41): 37-49, jan.-jun. 2015. ilus
Article in Portuguese | Index Psychology - journals | ID: psi-68313

ABSTRACT

Este artigo tem como objetivo analisar se as estratégias de aprendizagem autorregulatórias desenvolvidas em uma prática de ensino reflexiva contribuíram para a formação de alunos autorregulados e possibilitaram a promoção de avanços na aprendizagem de alunos do ensino superior relativas à escrita de um artigo científico. A prática de ensino reflexiva desenvolveu-se durante seis encontros nos quais buscou-se perceber a tomada de consciência, o controle e a gestão do aluno em seu processo de aprendizagem. Iniciou-se a pesquisa com a aplicação do questionário CEA (Conhecimento de Estratégias Autorregulatórias), seguido das “Oficinas de desenvolvimento de estratégias autorregulatórias da aprendizagem” as quais tiveram como objetivo principal, para os sujeitos pesquisados, aprender estratégias para a escrita de artigos científicos e, para a pesquisadora, analisar se as estratégias utilizadas nessa prática reflexiva promoveriam a autorregulação para a escrita de artigos científicos. Ao final dos encontros, após seis meses da intervenção, aplicou-se novamente o questionário CEA em uma entrevista semiestruturada. Da análise dos dados, emergiram duas categorias: 1) Estratégias Cognitivas e Metacognitivas; 2) Estratégias Motivacionais; que articuladas entre si contribuem significativamente para a formação de um aluno autorregulado. Conclui-se que os dados reforçam a importância do conhecimento de estratégias autorregulatórias nos processos de aprendizagem, a fim de que o aluno universitário seja capaz de atingir seus objetivos diante das tarefas, promovendo uma consciência reflexiva.(AU)


This article aims to examine whether self-regulatory learning strategies developed in a practice of reflective teaching contributed to the formation of self-regulated learners and enabled the promotion of advances in the learning of a group of students in higher education to support them in a scientific article production. The practice of reflective teaching, developed during six meetings, found if the student showed awareness, control and management of their learning process. We started the research with the questionnaire CEA (Knowledge of self-regulatory strategies), followed by six “Workshops for development of self-regulatory learning strategies”. These meetings mainly aimed for those individuals surveyed, learn strategies for writing papers and for the researcher to analyze the strategies used in this reflective practice in higher education, would promote self-regulation by stimulating the processes students learn college. At the end of the meetings, 6 months after the intervention was applied CEA questionnaire and a semi-structured interview. From the data analysis, two categories emerged: 1) Cognitive and Metacognitive Strategies; 2) Motivational Strategies; that articulated between them indicate that contributed significantly to the formation of the self-regulated learner. We conclude that the data support the importance of the knowledge of self-regulatory strategies in the learning process, so that the university student is able to achieve their goals in tasks, promoting a reflective consciousness.(AU)


Este artículo tiene como objetivo analizar si las estrategias de aprendizaje, de autorregulación desarrolladas en la práctica de la enseñanza reflexiva, contribuyeron a formación de estudiantes autorregulados y permitieron la promoción de los avances en la aprendizaje de un grupo de estudiantes de educación superior para la producción de un artículo científico. La práctica de la enseñanza reflexiva se desarrolló durante seis reuniones: pesquisó, a partir de las estrategias de aprendizaje de autorregulación, si estudiante mostro conciencia, control y gestión de su proceso de aprendizaje. Comenzó la investigación con la aplicación del cuestionario CEA (Conocimiento de Estrategias de Autorregulación), seguido de seis “Talleres de desarrollo de estrategias de autorregulación de la aprendizaje” como objetivo principal, para los sujetos, aprender estrategias para escribir artículos científicos y, para el investigador , analizar si las estrategias utilizadas en esta práctica reflexiva, promueven la autorregulación mediante la estimulación de los procesos de aprendizaje de los estudiantes de la universidad. Seis meses después de la intervención, se aplicó de nuevo cuestionario CEA y una entrevista semi-estructurada. Del análisis de datos, emergieron categorías: 1) Estrategias cognitivas y metacognitivas; 2) Estrategias de motivación. Os datos apoyan la importancia del conocimiento de las estrategias de autorregulación en el proceso de aprendizaje, por lo que el estudiante universitario es capaz de alcanzar sus objetivos en las tareas, con promoción de una conciencia reflexiva.(AU)


Subject(s)
Humans , Learning , Universities
3.
Arq Bras Cardiol ; 102(4): 327-35, 2014 Apr.
Article in English, Portuguese | MEDLINE | ID: mdl-24844874

ABSTRACT

BACKGROUND: Subclinical cardiovascular disease is prevalent in patients with Metabolic Syndrome (MetSyn). Left ventricular (LV) circumferential strain (εCC) and longitudinal strain (εLL), assessed by Speckle Tracking Echocardiography (STE), are indices of systolic function: shortening is indicated by negative strain, and thus, the more negative the strain, the better the LV systolic function. They have been used to demonstrate subclinical ventricular dysfunction in several clinical disorders. OBJECTIVE: We hypothesized that MetSyn is associated with impaired myocardial function, as assessed by STE. METHODS: We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent STE and were evaluated for all MetSyn components. RESULTS: Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ± SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had lower εCC and lower εLL than those without MetSyn (-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9% ± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was similar in both groups (p = 0.09). In multivariate analysis, MetSyn was associated with less circumferential myocardial shortening as indicated by less negative εCC (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95% CI: 0.01-0.03, p = 0.02) were significantly associated with less longitudinal myocardial shortening as indicated by less negative εLL after adjustment for ethnicity, LVEF, and creatinine. CONCLUSION: Left ventricular εCC and εLL, markers of subclinical cardiovascular disease, are impaired in asymptomatic individuals with MetSyn and no history of myocardial infarction, heart failure, and/or LVEF < 50%.


Subject(s)
Coronary Artery Disease/diagnostic imaging , Echocardiography/methods , Heart/physiopathology , Metabolic Syndrome/diagnostic imaging , Ventricular Dysfunction, Left/diagnostic imaging , Aged , Body Mass Index , Coronary Artery Disease/ethnology , Coronary Artery Disease/physiopathology , Female , Humans , Linear Models , Magnetic Resonance Imaging , Male , Metabolic Syndrome/ethnology , Metabolic Syndrome/physiopathology , Middle Aged , Multivariate Analysis , Observer Variation , Reference Values , Reproducibility of Results , Risk Factors , Stroke Volume/physiology , Systole/physiology , Ventricular Dysfunction, Left/ethnology , Ventricular Dysfunction, Left/physiopathology
4.
Arq. bras. cardiol ; Arq. bras. cardiol;102(4): 327-335, abr. 2014. tab, graf
Article in Portuguese | LILACS | ID: lil-709318

ABSTRACT

Fundamento: A doença cardiovascular subclínica é prevalente em pacientes com síndrome metabólica (SM). O strain circunferencial (εCC) e o strain longitudinal (εLL) do ventriculo esquerdo (VE), avaliados pelo ecocardiograma com speckle tracking (STE), são índices de função sistólica: o encurtamento das fibras circunferenciais e longitudinais do VE é indicado por um valor negativo do strain. Portanto, quanto mais negativo o strain, melhor a função sistólica do VE. O εCC e o εLL têm sido usados para demonstrar disfunção ventricular subclínica em vários distúrbios clínicos. Objetivo: Levantamos a hipótese de que a SM está associada com comprometimento da função miocárdica, quando avaliada pelo STE. Métodos: Este estudo analisou participantes do Multi-Ethnic Study of Atherosclerosis (MESA) que realizaram o STE e foram avaliados para todos os componentes da SM. Resultados: Entre os 133 participantes incluídos (mulheres: 63%; idade: 65 ± 9 anos), a prevalência de SM foi de 31% (41/133). Indivíduos com SM apresentaram valores menores do εCC e do εLL que aqueles sem SM (-16,3% ± 3,5% vs. -18,4% ± 3,7%, p < 0,01; e -12,1% ± 2,5% vs. -13,9% ± 2,3%, p < 0,01, respectivamente). A fração de ejeção do VE (FEVE) foi semelhante nos dois grupos (p = 0,09). Na análise multivariada, a SM associou-se a um valor mais baixo do strain circunferencial (B = 2,1%, IC 95%: 0,6-3,5; p < 0,01), mesmo após ajuste para idade, etnia, massa VE e FEVE. De maneira semelhante, a presença de SM (B = 1,3%, IC 95%: 0,3-2,2; p < 0,01) e a massa do VE (B = 0,02%, IC 95%: 0,01 0,03; p = 0,02) associaram-se a um valor menor do strain longitudinal após ajuste para etnia, FEVE e creatinina. Conclusão: O εCC ...


Background: Subclinical cardiovascular disease is prevalent in patients with Metabolic Syndrome (MetSyn). Left ventricular (LV) circumferential strain (εCC) and longitudinal strain (εLL), assessed by Speckle Tracking Echocardiography (STE), are indices of systolic function: shortening is indicated by negative strain, and thus, the more negative the strain, the better the LV systolic function. They have been used to demonstrate subclinical ventricular dysfunction in several clinical disorders. Objective: We hypothesized that MetSyn is associated with impaired myocardial function, as assessed by STE. Methods: We analyzed Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent STE and were evaluated for all MetSyn components. Results: Among the 133 participants included [women: 63%; age: 65 ± 9 years (mean ± SD)], the prevalence of MetSyn was 31% (41/133). Individuals with MetSyn had lower εCC and lower εLL than those without MetSyn (-16.3% ± 3.5% vs. -18.4% ± 3.7%, p < 0.01; and -12.1% ± 2.5% vs. -13.9% ± 2.3%, p < 0.01, respectively). The LV ejection fraction (LVEF) was similar in both groups (p = 0.09). In multivariate analysis, MetSyn was associated with less circumferential myocardial shortening as indicated by less negative εCC (B = 2.1%, 95%CI:0.6 3.5, p < 0.01) even after adjusting for age, ethnicity, LV mass, and LVEF). Likewise, presence of MetSyn (B = 1.3%, 95%CI:0.3 2.2, p < 0.01) and LV mass (B = 0.02%, 95% CI: 0.01-0.03, p = 0.02) were significantly associated with less longitudinal myocardial shortening as indicated by less negative εLL after adjustment for ethnicity, LVEF, and creatinine. Conclusion: Left ventricular εCC and εLL, markers of subclinical cardiovascular disease, are impaired in asymptomatic individuals with MetSyn and no history of myocardial infarction, heart failure, and/or LVEF < 50%. .


Subject(s)
Aged , Female , Humans , Male , Middle Aged , Coronary Artery Disease , Echocardiography/methods , Heart/physiopathology , Metabolic Syndrome , Ventricular Dysfunction, Left , Body Mass Index , Coronary Artery Disease/ethnology , Coronary Artery Disease/physiopathology , Linear Models , Magnetic Resonance Imaging , Multivariate Analysis , Metabolic Syndrome/ethnology , Metabolic Syndrome/physiopathology , Observer Variation , Reference Values , Reproducibility of Results , Risk Factors , Stroke Volume/physiology , Systole/physiology , Ventricular Dysfunction, Left/ethnology , Ventricular Dysfunction, Left/physiopathology
5.
Arq. bras. cardiol ; Arq. bras. cardiol;98(5): 421-430, maio 2012. ilus, tab
Article in Portuguese | LILACS | ID: lil-643640

ABSTRACT

FUNDAMENTO: Testes invasivos e não invasivos têm sido usados para identificar risco para Taquicardia Ventricular (TV) em pacientes com Cardiopatia Chagásica Crônica (CCC). Ressonância Magnética Cardíaca (RMC) pela técnica do Realce Tardio (RT) pode ser útil para selecionar pacientes com disfunção ventricular global ou segmentar, com alto grau de fibrose e maior risco para TV clínica. OBJETIVO: Melhorar a identificação de elementos preditivos de TV em pacientes com CCC. MÉTODO: Quarenta e um pacientes com CCC foram pesquisados, sendo 30 (72%) do sexo masculino, com média de idade de 55,1 ± 11,9 anos. Vinte e seis pacientes apresentavam histórico de TV (grupo TV), e 15 não apresentavam TV (grupo NTV). Todos os pacientes incluídos tinham RT e disfunção segmentar ventricular. Volume, porcentagem de comprometimento da espessura da parede ventricular em cada segmento, e distribuição de RT foi determinado em cada caso. RESULTADOS: Não houve diferença estatística em termos de volume de RT entre os dois grupos: grupo TV = 30,0 ± 16,2%; grupo NTV = 21,7 ± 15,7%; p = 0,118. A probabilidade de TV foi maior se duas ou mais áreas contíguas de fibrose transmural estivessem presentes, sendo um fator preditor de TV clínica (RR 4,1; p = 0,04). A concordância entre os observadores foi de 100% nesse critério (p < 0,001). CONCLUSÃO: A identificação de dois ou mais segmentos de RT transmural por RMC está associado com a ocorrência de TV clínica em pacientes com CCC. Portanto, a RMC melhora a estratificação de risco na população estudada. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0).


BACKGROUND: Invasive and non-invasive tests have been used to identify the risk of ventricular tachycardia (VT) in patients with chronic Chagas' heart disease (CCHD). Cardiac magnetic resonance imaging (CMRI) using the delayed enhancement (DE) technique can be useful to select patients with global or segmentary ventricular dysfunction, with high degree of fibrosis and at higher risk for clinical VT. OBJECTIVE: To improve the identification of predictors of VT in patients with CCHD. METHOD: This study assessed 41 patients with CCHD [30 (72%) males; mean age, 55.1 ± 11.9 years]. Twenty-six patients had history of VT (VT group), and 15 had no VT (NVT group). All patients enrolled had DE and segmentary ventricular dysfunction. In each case, the following variables were determined: left ventricular volume; percentage of ventricular wall thickness impairment in each segment; and DE distribution. RESULTS: No statistical difference regarding the DE volume between both groups was observed: VT group = 30.0 ± 16.2%; NVT group = 21.7 ± 15.7%; p = 0.118. The probability of VT was greater in the presence of two or more contiguous transmural fibrosis areas, and that was a predictive factor of clinical VT (RR 4.1; p = 0,04). Agreement between observers was 100% regarding that criterion (p < 0.001). CONCLUSION: The identification of two or more segments of transmural DE by use of CMRI is associated with the occurrence of clinical VT in patients with CCHD. Thus, CMRI improved risk stratification in the population studied. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0).


Subject(s)
Adult , Aged , Female , Humans , Middle Aged , Chagas Disease/complications , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Tachycardia, Ventricular/diagnosis , Heart/physiopathology , Predictive Value of Tests , Prospective Studies , Reference Values , Risk Assessment , Sex Factors
6.
Arq Bras Cardiol ; 98(5): 421-30, 2012 May.
Article in English, Portuguese | MEDLINE | ID: mdl-22460166

ABSTRACT

BACKGROUND: Invasive and non-invasive tests have been used to identify the risk of ventricular tachycardia (VT) in patients with chronic Chagas' heart disease (CCHD). Cardiac magnetic resonance imaging (CMRI) using the delayed enhancement (DE) technique can be useful to select patients with global or segmentary ventricular dysfunction, with high degree of fibrosis and at higher risk for clinical VT. OBJECTIVE: To improve the identification of predictors of VT in patients with CCHD. METHOD: This study assessed 41 patients with CCHD [30 (72%) males; mean age, 55.1 ± 11.9 years]. Twenty-six patients had history of VT (VT group), and 15 had no VT (NVT group). All patients enrolled had DE and segmentary ventricular dysfunction. In each case, the following variables were determined: left ventricular volume; percentage of ventricular wall thickness impairment in each segment; and DE distribution. RESULTS: No statistical difference regarding the DE volume between both groups was observed: VT group = 30.0 ± 16.2%; NVT group = 21.7 ± 15.7%; p = 0.118. The probability of VT was greater in the presence of two or more contiguous transmural fibrosis areas, and that was a predictive factor of clinical VT (RR 4.1; p = 0,04). Agreement between observers was 100% regarding that criterion (p < 0.001). CONCLUSION: The identification of two or more segments of transmural DE by use of CMRI is associated with the occurrence of clinical VT in patients with CCHD. Thus, CMRI improved risk stratification in the population studied.


Subject(s)
Chagas Disease/complications , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Tachycardia, Ventricular/diagnosis , Adult , Aged , Female , Heart/physiopathology , Humans , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Reference Values , Risk Assessment , Sex Factors
7.
Arq. ciências saúde UNIPAR ; 10(3): 151-154, set.-dez. 2006. graf
Article in Portuguese | LILACS | ID: lil-498952

ABSTRACT

O desenvolvimento de um câncer é um processo de múltiplos passos, em que as células se tornam malignas por meio de uma série progressiva de alterações. Na maioria das vezes se desenvolve em fase mais tardia da vida. A radiação solar tem efeitos profundos sobre a pele e está associada a uma variedade de doenças, sendo responsável pela maioria das reações cutâneas fotobiológicas, principalmente o câncer de pele. A ação agressiva da radiação solar sobre a pele afeta o DNA, ocasionando várias alterações. Geralmente os alunos se expõem freqüentemente ao sol para praticar suas aulas de educação física, esportes em geral e lazer, sendo a faixa etária que mais freqüenta clubes e piscinas no verão. O presente trabalho teve como objetivo comparar a percepção entre alunos do ensino fundamental (5ª a 8ª) e médio em duas escolas públicas de Cianorte, Estado do Paraná, em relação às causas do câncer de pele e verificar os cuidados tomados pelos estudantes ao se exporem à radiação solar. Foram aplicados 151 questionários com itens referentes à caracterização individual como: sexo, idade e hábitos relativos à exposição solar. Verificou-se que a maioria dos alunos se expõe ao sol em horários impróprios e usam protetor solar somente quando vão às praias. Assim, foi possível verificar que a maioria dos alunos conhece os riscos e danos relacionados à exposição solar, como também as causas responsáveis pelo câncer de pele, porém não fazem proteção adequada quando expostos ao sol.


Cancer development is a multiple-step process as the cells themselves become malicious throughout a number of progressive alterations. It usually develops in late period of someone's life. Solar radiation causes severe effects upon the skin as it is associated with several diseases being responsible for most of the skin photobiological reactions, especially skin cancer. The solar radiation aggressive action over the skin affects the DNA by causing a number of changes. Students usually expose themselves to the Sun during their Physical Education classes, Sports in general, and leisure, they are also the ones who most often go to swimming pools and Recreational Center in Summer. The present article aimed at comparing middle school students (5th to 8th grade) and High school students from two public schools in Cianorte, Paraná related to skin cancer causes, as well as verifying the precautions taken by the students while exposing themselves to solar radiation. There was a 151 questionnaire with items regarding individual characteristics as: gender, age, and habits related to solar exposition. It was verifi ed that most of the students would expose themselves during an improper time of the day, and used sun scream only when they would go to the beaches. Therefore, it was possible to verify that most of the students have learned about the risks and damages related to solar expose as well as the causes of skin cancer; however they do not take appropriate protection while exposing themselves to the Sun.


Subject(s)
Humans , Male , Female , Child , Adolescent , Skin Neoplasms , Sunburn , Sunscreening Agents , Ultraviolet Rays
8.
Mem. Inst. Oswaldo Cruz ; 82(supl.3): 29-34, 1987. ilus
Article in English | LILACS | ID: lil-623734

ABSTRACT

Columnar cell apical membranes (CCAM) in series with goblet cell apical membranes (GCAM) form an electroosmotic barrier separating the midgut lumen from epithelial cell cytoplasm. A unique K+ ATPase in GCAM generates three gradients across this barrier. A greater than 180 mV electrical gradient (lumen positive) drives amino acid uptake through voltage-dependent K+ symports. A greater than 1000-fold [H+] gradient (lumen alkaline) and a greater than 10-fold [K+] gradient (lumen concentrated) are adaptations to the high tannin and high K+ content, respectively, in dietary plant material. Agents which act on the apical membrane and disrupt the PD, H+, or K+ gradients are potential insecticides. Insect sensory epithelia and mammalian stria vascularis maintain similar PD and K+ gradients but would not be exposed to ingested anti-apical membrane insecticides. Following the demonstration by Sacchi et al. that Bacillus thuringiensis delta-endotoxin (Bt) induces specifically a K+ conductance increase in CCAM vesicles, we find that the K+ channel blocking agent, Ba2+, completely reverses Bt inhibition of the K+-carried short circuit current in the isolated midgut of Manduca sexta. Progress in characterizing the apical membrane includes finding that fluorosulfonylbenzoyladenosine binds specifically to certain GCAM polypeptides and that CCAM vesicles can be mass produced by Ca2+ or Mg2+ precipitation from Manduca sexta midgut.


Subject(s)
Humans , Agriculture , Biological Control Agents/therapeutic use , Potassium/therapeutic use
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