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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Conceptual Evaluation Framework for Measuring Fruit and Vegetable Consumption at School Lunch among Elementary Students Participating in the National School Lunch Program

Graziose, Matthew January 2017 (has links)
In the U.S., few children meet federal recommendations for fruit and vegetable consumption, putting them at increased risk for overweight, obesity and several non-communicable diseases. Interventions to increase fruit and vegetable consumption delivered within the school setting are advantageous in that they provide the opportunity to reach many youths in period of life during which key diet-related behaviors are formed that may track into adulthood. The National School Lunch Program (NSLP), a federal food assistance program that serves over 30 million meals daily in over 100,000 schools in the U.S., is one example of an intervention that may increase fruit and vegetable consumption among children. Recent regulatory changes to the program via the 2010 Healthy Hunger-Free Kids Act (HHFKA) require compliance with minimum daily and weekly minimums for fruit and vegetables offered to students at lunch to receive federal reimbursement, which has resulted in increased availability of fruits and vegetables. Although preliminary evaluations of the regulatory changes have documented small increases in consumption, there is interest in identifying other programs and policies to ensure that components are consumed. Yet there is little meta-evidence that critically examines aspects related to the design of school-based intervention studies assessing fruit and vegetable consumption. This dissertation describes a systematic mapping review of the literature and three empirical studies which inform the development of a conceptual evaluation framework for designing studies to measure fruit and vegetable consumption among elementary students in the U.S. within schools participating in the NSLP. A systematic mapping review of the literature technique was used to identify studies conducted among elementary students in grades K-5th within schools in the United States in the period from 2004 to present with the primary outcome fruit and vegetable consumption at the lunch meal. A total of 61 records were included in the review, categorized as either methodological validation studies (n=10) or as studies of factors related to students’ consumption of fruits and vegetables (n=51). Validation studies were conducted with four types of dietary assessment methods within the school lunch setting, all demonstrating moderate accuracy relative to the referent method: weighed plate waste, direct observation, digital photography and self-report instruments. In the studies examining factors related to fruit and vegetable consumption at school lunch, the frequency of methods was as follows: weighed plate waste method (n=21), direct observation (n=14), digital photography methodology (n=12), and self-report (n=4). Most studies utilized cross-sectional (n=15) or quasi-experimental designs (n=24). A socio-ecological framework was used to group 19 environmental factors examined in these studies into 5 clusters of factors: individual, item-specific, meal-specific, cafeteria environment and school-wide/policy. While many factors were explored across studies, relatively few studies accounted for multiple factors in their analyses, leaving room for potential confounding. Three empirical studies were conducted within a larger, cross-sectional evaluation of FoodCorps, a national farm-to-school program that promotes fruit and vegetable consumption in school-aged children. First, this dissertation conducted a validation study to estimate the accuracy of a self-report questionnaire instrument relative to digital photography for measuring fruit and vegetable consumption in elementary students from 23 schools in a five-phase study. High agreement was observed between student reports of fruit and vegetable items on tray and items observed in digital photographs (match rate ranged from 77 to 88% depending on phase), as well as reports of amounts of fruit and vegetable items consumed (ranges from 67 to 83% depending on phase). There were no differences observed in accuracy of reporting between 2nd and 3rd grade students. It can therefore be concluded that a group-administered self-report instrument can be used to measure fruit and vegetable consumption in a school setting among 2nd and 3rd grade students, providing a potentially less costly instrument than existing objective methods. Second, a descriptive study reports intra-class correlation estimates for fruit and vegetable outcomes, quantifying the variation in these outcomes attributable to the school-level that can be used in power calculation for future studies. Using 2,571 before- and after-meal digital photographs collected of students’ lunch trays across 40 days of data collection within 20 schools, the intra-class correlation coefficients (ICC) were estimated via multilevel regression models. The observed ICCs for all fruit and vegetable consumption outcomes ranged from 0.159 (vegetables on tray, continuous) to 0.472 (vegetables on tray, binary). Within each of food item category (fruit, vegetables, or fruit and vegetables combined), the highest ICC was observed for items on tray (binary). A multilevel linear model which included as covariates the percent of students eligible for free/reduced price lunch and the percent of white students was shown to decrease the ICC for each fruit and vegetable outcome variable except fruit on tray (binary). The largest for decrease in ICC was for the outcome fruit and vegetables on tray (in cup equivalents), wherein the model reduced ICC from 0.268 to 0.018, a 93% decrease. The power calculations for cluster randomized controlled trial that can conducted using these ICCs will help to ensure that researchers have adequately powered their studies. Third, select cafeteria environmental factors were examined in a cross-sectional study as they relate to students’ fruit and vegetable consumption at the lunch meal. Using the digital photographs of 2,571 lunch trays from the previous study, the association between fruit and vegetable consumption and several environmental factors was examined. The average consumption of fruit and vegetables was 0.35 cup equivalents (SD=0.31) and 0.24 cup equivalents (SD=0.29), respectively, among students who had them on their tray. When considering students who had a fruit or a vegetable or both on their tray (96% of the sample), the average was 0.45 cup equivalents (SD=0.40). Hierarchical linear models examined environmental variables and fruit and vegetable consumption outcomes: the number of fruit and vegetable items offered (range from 3 to 14 items) was positively associated with vegetable consumption (B=0.021; SE=0.006; P<0.001); noise (rage from 70 DbA to 84 DbA) was negatively associated with fruit consumption (B=-0.012; SE=0.004; P=0.003) and fruit and vegetable consumption (B=-0.017; SE=0.004; P<0.001); recess scheduled before lunch was positively associated with fruit consumption (relative to recess after lunch; B=0.100; SE=0.023; P<0.001) and fruit and vegetable consumption (B=0.096; SE=0.023; P<0.001). Despite cross-sectional evidence of an association, future research is necessary to systematically manipulate these variables to understand their impact. The results from these three studies and the systematic mapping review are used to develop a conceptual evaluation framework that can be used by researchers to improve the quality and design of studies promoting fruit and vegetable consumption among elementary school-aged children in the U.S.
2

Análise comparativa de legislações internacionais referentes aos alimentos funcionais / Analyzing and comparing international legislation relating to functional foods

Roberta Calhes Franco 12 June 2006 (has links)
Revisão com o objetivo de analisar e comparar a legislação brasileira, nos aspectos de desenvolvimento, avaliação e comercialização dos alimentos funcionais, com a legislação dos países: Austrália, Canadá, Estados Unidos, Japão; da União Européia e a opinião do Codex Alimentarius. Separou-se e analisou-se a legislação desses alimentos em cinco partes: a) Definição legal; b) Regulamentação; c) Alegações; d) Procedimentos de comunicação das alegações; e) Critérios de avaliação da segurança e eficácia desses alimentos. Constatou-se que, dos países analisados, somente o Japão possui uma definição legal e uma regulamentação própria para essa categoria de produto e que o Canadá é o único país que apresenta uma norma clara e objetiva sobre a divulgação, nos meios de comunicação, dos alimentos com alegações. Verificou-se que existem diferentes tipos de definições e usos para as alegações, sendo algumas vezes equivalentes entre os países e outras não. Constatou-se que todos os países em estudo compartilham de alguns pontos comuns quanto aos critérios de avaliação, como: as alegações devem ser baseadas em estudos científicos relevantes; e o produto deve ser seguro sem a necessidade de supervisão médica. A Austrália, o Canadá, os Estados Unidos, a União Européia e o Reino Unido dispõem de guias de orientações bem explicativos sobre como as alegações devem ser avaliadas. Levando-se em conta as orientações fornecidas por esses documentos, elaborou-se uma sugestão de guia sobre os procedimentos/passos para se avaliar a segurança e a veracidade de uma alegação. / This is a review with the aim of analyzing and comparing Brazilian legislation relating to aspects of the development, evaluation and commercialization of functional foods, with that of Australia, Canada, the United States of America, Japan, and the European Union, and with the opinions expressed in the Codex Alimentarius. This food legislation was separated and analyzed in five distinct parts: a) The legal definition; b) Regulations; c) Claims; d) Procedures for communicating claims; and) Criteria for evaluating the security and effective of these foods. It was noticed that from all the analysed countries, only Japan has a legal definition and a regulation that fits sort of product and that Canada is the only country that has an objective and unambiguous norm on divulging the nutriments with claims among communication. With regard to claims, it was noticed that there are different types of definition and uses that sometimes have counterparts in other countries and sometimes not. In the part dealing with the evaluation criteria of these foods, it was noticed that all countries in the study have some points in common. Among these points are that the claims must be based on relevant scientific studies and that the product must be safe without the need for medical supervision. Australia, Canada, the United States, the European Union and the United Kingdom have very explicit guidelines regarding how the claims should be evaluated. Taking into consideration the guidelines supplied in these documents it was prepared a suggested guide for procedures/steps for evaluating the security and truth of the claims.
3

Critérios de avaliação de risco de praguicidas em alimentos vegetais como ferramenta de gerenciamento da segurança alimentar no Brasil / Criteria for assessing the risk of pesticides in plant foods as a food safety management tool in Brazil

Regiane Guimarães Landi Pereira 02 August 2005 (has links)
A segurança alimentar tem sido um tema cada vez mais importante das metas dos órgãos governamentais, não apenas no sentido de garantir que a população dos países tenha acesso a alimentos, mas que estes alimentos estejam dentro de padrões de qualidade nutricional e os limites de resíduos químicos ou microrganismos não causem prejuízos à saúde da população. A comparação entre as legislações existentes no Codex Alimentarius, nos Estados Unidos e no Reino Unido, sobre a maneira como os limites de segurança alimentar de praguicidas são obtidos, permitirá a obtenção de subsídios que, certamente, contribuirão para a construção de uma proposta para a avaliação deste risco no Brasil. A avaliação do risco da ingestão de resíduos de praguicidas presentes no alimento é feita pressupondo-se que Risco = f(toxicidade, exposição), onde a toxicidade é inerente ao praguicida, sendo determinada em estudos conduzidos em animais de laboratório. Já os dados de exposição são oriundos dos estudos de campo e de consumo dos alimentos. Países como os Estados Unidos e o Reino Unido, preconizam que a avaliação do risco deva ser feita por etapas, partindo do cenário mais restritivo e quando este se mostrar impeditivo, fazer um refinamento dos dados, considerando outros cenários de exposição para posterior tomada de decisão. No presente trabalho foram comparados dois praguicidas de uso autorizado no Brasil, nos Estados Unidos e no Reino Unido e que apresentam tolerância estabelecida pelo Codex Alimentarius. Foram utilizados os modelos de cálculo de cada entidade regulamentadora e obtidos os seguintes resultados: no Brasil o Clorpirifós atinge 41,03% da IDA, para as demais entidades o valor é inferior a 4,5% da IDA. No caso do Tebuconazol, observa-se que no Brasil o produto atinge 35, 17 % da IDA e nas demais instituições o valor é inferior a 8% da IDA. Diante dos resultados obtidos, temos que o critério adotado pelo governo brasileiro encontra-se distante da realidade, e embora o valor obtido no cálculo seja maior do que nas demais instituição, este não significa que a população brasileira está mais protegida do que as demais. Existe a necessidade de implementar o banco de dados brasileiro para que a avaliação do risco seja feita de forma mais adequada, possibilitando a geração de informações que suportem o gerenciamento do risco e viabilize medidas adequadas de mitigação deste risco, quando existente. Embora o Brasil seja um membro signatário do Codex Alimentarius muitos critérios e conceitos desta entidade não foram implementados pelo governo brasileiro. / Food safety is an important goal for governmental agencies, not only aiming access to food by populations in all countries, but also assume nutritional quality standards and limits of chemical residues or microorganisms that do not cause damages to the population. The comparison of existing legislations in the Codex Alimentarius, United States and United Kingdom in relation to the procedure on how pesticide limits of food safety are established will allow the attainment of subsidies that, certainly, will contribute for the elaboration of a proposal for risk evaluation in Brazil. Risk evaluation of the ingestion of pesticide residues in food is made estimating that Risk = f(toxicity, exposure), where the toxicity is inherent to the pesticide, and it is determined by animal assays a exposure data are derived from field studies and food consumption. United States and the United Kingdom, consider that risk evaluation must be established by stages, starting from the most restrictive cenario and when it is impeditive, it is necessary a refinement of the data, considering other exposure situations for final decision. ln the present work two pesticides of authorized use in Brazil had been compared, with the United States and the United Kingdom and with the tolerance established for the Codex Alimentarius. The models used for calculation showed that in Brazil, Chlorpyrifos reached 41.03% of the ADI , and the other institutions showed value below of 4,5% of the ADI. In the case of Tebuconazole it is observed that in Brazil the product reaches 35, 17 % of the ADI and in the other institutions the value was lower than 8% of the ADI. The results showed that the criterion adopted by the Brazilian government are unreal, and even if they are higher than the ones found by other institutions, they do not mean that the Brazilian population is more protected than the others. It is necessary to implement Brazilian data base in relation to food consumption so that the risk evaluation can be more reliable and consistent to allow an effective risk management, when needed. Although Brazil is a signatary member of the Codex Alimentarius many criteria and concepts of this entity had not been yet implemented by the government.
4

Critérios de avaliação de risco de praguicidas em alimentos vegetais como ferramenta de gerenciamento da segurança alimentar no Brasil / Criteria for assessing the risk of pesticides in plant foods as a food safety management tool in Brazil

Pereira, Regiane Guimarães Landi 02 August 2005 (has links)
A segurança alimentar tem sido um tema cada vez mais importante das metas dos órgãos governamentais, não apenas no sentido de garantir que a população dos países tenha acesso a alimentos, mas que estes alimentos estejam dentro de padrões de qualidade nutricional e os limites de resíduos químicos ou microrganismos não causem prejuízos à saúde da população. A comparação entre as legislações existentes no Codex Alimentarius, nos Estados Unidos e no Reino Unido, sobre a maneira como os limites de segurança alimentar de praguicidas são obtidos, permitirá a obtenção de subsídios que, certamente, contribuirão para a construção de uma proposta para a avaliação deste risco no Brasil. A avaliação do risco da ingestão de resíduos de praguicidas presentes no alimento é feita pressupondo-se que Risco = f(toxicidade, exposição), onde a toxicidade é inerente ao praguicida, sendo determinada em estudos conduzidos em animais de laboratório. Já os dados de exposição são oriundos dos estudos de campo e de consumo dos alimentos. Países como os Estados Unidos e o Reino Unido, preconizam que a avaliação do risco deva ser feita por etapas, partindo do cenário mais restritivo e quando este se mostrar impeditivo, fazer um refinamento dos dados, considerando outros cenários de exposição para posterior tomada de decisão. No presente trabalho foram comparados dois praguicidas de uso autorizado no Brasil, nos Estados Unidos e no Reino Unido e que apresentam tolerância estabelecida pelo Codex Alimentarius. Foram utilizados os modelos de cálculo de cada entidade regulamentadora e obtidos os seguintes resultados: no Brasil o Clorpirifós atinge 41,03% da IDA, para as demais entidades o valor é inferior a 4,5% da IDA. No caso do Tebuconazol, observa-se que no Brasil o produto atinge 35, 17 % da IDA e nas demais instituições o valor é inferior a 8% da IDA. Diante dos resultados obtidos, temos que o critério adotado pelo governo brasileiro encontra-se distante da realidade, e embora o valor obtido no cálculo seja maior do que nas demais instituição, este não significa que a população brasileira está mais protegida do que as demais. Existe a necessidade de implementar o banco de dados brasileiro para que a avaliação do risco seja feita de forma mais adequada, possibilitando a geração de informações que suportem o gerenciamento do risco e viabilize medidas adequadas de mitigação deste risco, quando existente. Embora o Brasil seja um membro signatário do Codex Alimentarius muitos critérios e conceitos desta entidade não foram implementados pelo governo brasileiro. / Food safety is an important goal for governmental agencies, not only aiming access to food by populations in all countries, but also assume nutritional quality standards and limits of chemical residues or microorganisms that do not cause damages to the population. The comparison of existing legislations in the Codex Alimentarius, United States and United Kingdom in relation to the procedure on how pesticide limits of food safety are established will allow the attainment of subsidies that, certainly, will contribute for the elaboration of a proposal for risk evaluation in Brazil. Risk evaluation of the ingestion of pesticide residues in food is made estimating that Risk = f(toxicity, exposure), where the toxicity is inherent to the pesticide, and it is determined by animal assays a exposure data are derived from field studies and food consumption. United States and the United Kingdom, consider that risk evaluation must be established by stages, starting from the most restrictive cenario and when it is impeditive, it is necessary a refinement of the data, considering other exposure situations for final decision. ln the present work two pesticides of authorized use in Brazil had been compared, with the United States and the United Kingdom and with the tolerance established for the Codex Alimentarius. The models used for calculation showed that in Brazil, Chlorpyrifos reached 41.03% of the ADI , and the other institutions showed value below of 4,5% of the ADI. In the case of Tebuconazole it is observed that in Brazil the product reaches 35, 17 % of the ADI and in the other institutions the value was lower than 8% of the ADI. The results showed that the criterion adopted by the Brazilian government are unreal, and even if they are higher than the ones found by other institutions, they do not mean that the Brazilian population is more protected than the others. It is necessary to implement Brazilian data base in relation to food consumption so that the risk evaluation can be more reliable and consistent to allow an effective risk management, when needed. Although Brazil is a signatary member of the Codex Alimentarius many criteria and concepts of this entity had not been yet implemented by the government.
5

Análise comparativa de legislações internacionais referentes aos alimentos funcionais / Analyzing and comparing international legislation relating to functional foods

Franco, Roberta Calhes 12 June 2006 (has links)
Revisão com o objetivo de analisar e comparar a legislação brasileira, nos aspectos de desenvolvimento, avaliação e comercialização dos alimentos funcionais, com a legislação dos países: Austrália, Canadá, Estados Unidos, Japão; da União Européia e a opinião do Codex Alimentarius. Separou-se e analisou-se a legislação desses alimentos em cinco partes: a) Definição legal; b) Regulamentação; c) Alegações; d) Procedimentos de comunicação das alegações; e) Critérios de avaliação da segurança e eficácia desses alimentos. Constatou-se que, dos países analisados, somente o Japão possui uma definição legal e uma regulamentação própria para essa categoria de produto e que o Canadá é o único país que apresenta uma norma clara e objetiva sobre a divulgação, nos meios de comunicação, dos alimentos com alegações. Verificou-se que existem diferentes tipos de definições e usos para as alegações, sendo algumas vezes equivalentes entre os países e outras não. Constatou-se que todos os países em estudo compartilham de alguns pontos comuns quanto aos critérios de avaliação, como: as alegações devem ser baseadas em estudos científicos relevantes; e o produto deve ser seguro sem a necessidade de supervisão médica. A Austrália, o Canadá, os Estados Unidos, a União Européia e o Reino Unido dispõem de guias de orientações bem explicativos sobre como as alegações devem ser avaliadas. Levando-se em conta as orientações fornecidas por esses documentos, elaborou-se uma sugestão de guia sobre os procedimentos/passos para se avaliar a segurança e a veracidade de uma alegação. / This is a review with the aim of analyzing and comparing Brazilian legislation relating to aspects of the development, evaluation and commercialization of functional foods, with that of Australia, Canada, the United States of America, Japan, and the European Union, and with the opinions expressed in the Codex Alimentarius. This food legislation was separated and analyzed in five distinct parts: a) The legal definition; b) Regulations; c) Claims; d) Procedures for communicating claims; and) Criteria for evaluating the security and effective of these foods. It was noticed that from all the analysed countries, only Japan has a legal definition and a regulation that fits sort of product and that Canada is the only country that has an objective and unambiguous norm on divulging the nutriments with claims among communication. With regard to claims, it was noticed that there are different types of definition and uses that sometimes have counterparts in other countries and sometimes not. In the part dealing with the evaluation criteria of these foods, it was noticed that all countries in the study have some points in common. Among these points are that the claims must be based on relevant scientific studies and that the product must be safe without the need for medical supervision. Australia, Canada, the United States, the European Union and the United Kingdom have very explicit guidelines regarding how the claims should be evaluated. Taking into consideration the guidelines supplied in these documents it was prepared a suggested guide for procedures/steps for evaluating the security and truth of the claims.
6

Geraniol, mas não beta-ionona ou associação desses isoprenóides, possui atividade quimiopreventiva em ratos submetidos a modelo de carcinogênese de cólon / Geraniol, but not beta-ionone or association this isoprenoids, has chemopreventive activity in rats submitted to model of colon carcinogenesis

Vieira, Alessandra 05 October 2007 (has links)
Diversos estudos epidemiológicos têm demonstrado que isoprenóides presentes em frutas e hortaliças possuem ação protetora contra o desenvolvimento de câncer. Objetivou-se, no presente trabalho, avaliar as eventuais atividades quimiopreventivas dos isoprenóides geraniol (GO) e beta-ionona (BI) quando administrados a ratos Wistar, isoladamente ou em associação, continuamente durante as etapas de iniciação e pós-iniciação de modelo de carcinogênese de cólon induzida por dimetilhidrazina. A atividade quimiopreventiva desses compostos foi observada microscopicamente por meio da análise de Focos de Criptas Aberrantes (FCAs) em cólons corados com azul de metileno (0,02%). Verificou-se que, em comparação ao grupo controle apenas os ratos tratados com GO, mas não com BI, apresentaram redução (p&#8804;0,05) do número de lesões pré-neoplásicas (FCAs), no cólon distal, tanto em relação ao número de focos totais quanto aqueles com número maior ou igual do que quatro criptas. Por outro lado, somente tratamento com BI foi capaz de reduzir a concentração de colesterol plasmático total. Posteriormente, raspagem da mucosa colônica foi utilizada para a avaliação de danos no DNA pelo método do \"Cometa\". Em comparação ao grupo controle, tratamentos com GO, BI e GO+BI reduziram (p&#8804;O,05) o comprimento dos cometas indicando, dessa forma, diminuição de danos no DNA. Avaliou-se, ainda, a expressão de Bcl-2, em nível de proteína, em mucosas colônicas dos animais dos diferentes grupos pela técnica Western Blot. Foi possível notar uma redução nos valores da expressão pelos tratamentos com GO (p&#8804;0,05). Embora somente o tratamento com GO tenha inibido a formação de FCAs, tratamentos com BI e GO+BI podem ter apresentado efeitos protetores por inibirem os danos do DNA que não foram suficiente para a inibição da formação e crescimento de lesões pré-neoplásicas. / Several epidemiologic studies have shown consistently that isoprenoids presents in fruits and vegetables have a protective action against cancer. The objective of this study was to evaluate the chemopreventive effects of isoprenoids geraniol (GO) and beta-ionone (BI) during the initiation and pós-initiation phases of in rats submitted to model of chemical colon carcinogenesis induced by dimethylhydrazine (DMH). Aberrant Crypt Focus (ACFs) were detected using a light microscope in colons stained with 0,02% methylene blue. Treatment with GO significantly suppressed the total number of ACF and ACFs &#8805; 4 crypts per colon compared with the control group com oil (p&#8804;0,05), mainly in the distal colon. In other hand, only treatment with BI reduced total plasma cholesterol levels compared with the control group (p&#8804;0,05). Subsequently colonic mucosa scraping was used for asses DNA damage through comet assay and expressed as comet length. DNA damage was inhibited in our study by all treatments (p&#8804;0,05). Analysis of Bcl-2 protein from colonic mucosa scraping by Western Blot showed that treatment with GO reduced the values of expression de Bcl-2 (p&#8804;0,05). Although the results of this study suggest that treatment with GO has chemopreventive effects, treatments with BI and GO+BI has initial protective action that maybe wasn\'t sufficient to reduce formation ACF.
7

Geraniol, mas não beta-ionona ou associação desses isoprenóides, possui atividade quimiopreventiva em ratos submetidos a modelo de carcinogênese de cólon / Geraniol, but not beta-ionone or association this isoprenoids, has chemopreventive activity in rats submitted to model of colon carcinogenesis

Alessandra Vieira 05 October 2007 (has links)
Diversos estudos epidemiológicos têm demonstrado que isoprenóides presentes em frutas e hortaliças possuem ação protetora contra o desenvolvimento de câncer. Objetivou-se, no presente trabalho, avaliar as eventuais atividades quimiopreventivas dos isoprenóides geraniol (GO) e beta-ionona (BI) quando administrados a ratos Wistar, isoladamente ou em associação, continuamente durante as etapas de iniciação e pós-iniciação de modelo de carcinogênese de cólon induzida por dimetilhidrazina. A atividade quimiopreventiva desses compostos foi observada microscopicamente por meio da análise de Focos de Criptas Aberrantes (FCAs) em cólons corados com azul de metileno (0,02%). Verificou-se que, em comparação ao grupo controle apenas os ratos tratados com GO, mas não com BI, apresentaram redução (p&#8804;0,05) do número de lesões pré-neoplásicas (FCAs), no cólon distal, tanto em relação ao número de focos totais quanto aqueles com número maior ou igual do que quatro criptas. Por outro lado, somente tratamento com BI foi capaz de reduzir a concentração de colesterol plasmático total. Posteriormente, raspagem da mucosa colônica foi utilizada para a avaliação de danos no DNA pelo método do \"Cometa\". Em comparação ao grupo controle, tratamentos com GO, BI e GO+BI reduziram (p&#8804;O,05) o comprimento dos cometas indicando, dessa forma, diminuição de danos no DNA. Avaliou-se, ainda, a expressão de Bcl-2, em nível de proteína, em mucosas colônicas dos animais dos diferentes grupos pela técnica Western Blot. Foi possível notar uma redução nos valores da expressão pelos tratamentos com GO (p&#8804;0,05). Embora somente o tratamento com GO tenha inibido a formação de FCAs, tratamentos com BI e GO+BI podem ter apresentado efeitos protetores por inibirem os danos do DNA que não foram suficiente para a inibição da formação e crescimento de lesões pré-neoplásicas. / Several epidemiologic studies have shown consistently that isoprenoids presents in fruits and vegetables have a protective action against cancer. The objective of this study was to evaluate the chemopreventive effects of isoprenoids geraniol (GO) and beta-ionone (BI) during the initiation and pós-initiation phases of in rats submitted to model of chemical colon carcinogenesis induced by dimethylhydrazine (DMH). Aberrant Crypt Focus (ACFs) were detected using a light microscope in colons stained with 0,02% methylene blue. Treatment with GO significantly suppressed the total number of ACF and ACFs &#8805; 4 crypts per colon compared with the control group com oil (p&#8804;0,05), mainly in the distal colon. In other hand, only treatment with BI reduced total plasma cholesterol levels compared with the control group (p&#8804;0,05). Subsequently colonic mucosa scraping was used for asses DNA damage through comet assay and expressed as comet length. DNA damage was inhibited in our study by all treatments (p&#8804;0,05). Analysis of Bcl-2 protein from colonic mucosa scraping by Western Blot showed that treatment with GO reduced the values of expression de Bcl-2 (p&#8804;0,05). Although the results of this study suggest that treatment with GO has chemopreventive effects, treatments with BI and GO+BI has initial protective action that maybe wasn\'t sufficient to reduce formation ACF.

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