Ensino de matemática em cursos em ciências biológicas e da área da saúde: percepções de estudantes de doutorado

Este artigo descreve as representações sociais de estudantes de doutorado da Universidade Federal da Grande Dourados, com relação ao ensino de matemática e estatística em cursos de graduação de Ciências Biológicas e da área da Saúde. Para coletar os dados realizamos entrevistas semiestruturadas, com dez estudantes de doutorado, no período de fevereiro a maio de 2018, com aplicação de um roteiro com oito perguntas fechadas, considerando as teorias das Representações Sociais e Aprendizagem Inteligente como suporte teórico. A discussão do resultado foi organizado, com base no método do discurso do sujeito coletivo e ferramentas do QualiquantiSoft. Os participantes do estudo não conseguem relacionar os conteúdos matemáticos ensinados nas disciplinas de Matemática e Estatística em seus cursos de graduação, com suas práticas profissionais e relataram que tiveram dificuldades na aprendizagem. Além disso, os estudantes não percebem a aplicação dos conteúdo matemático à Ciência Biológica ou Ciência da Saúde e eles foram unânimes em afirmar que a matemática é um instrumento para resolução de cálculos que envolvem problemas biológicos. As representações sociais apresentadas no discurso do sujeito coletivo nos direcionam a refletir que no ensino superior, ainda prevalece o ensino da matemática instrumental e pouco desenvolvimento da compreensão e matemática relacional na sala de aula

Antioxidant, Cytotoxic, and Toxic Activities of Propolis from Two Native Bees in Brazil: Scaptotrigona depilis and Melipona quadrifasciata anthidioides

Propolis is a natural mixture of compounds produced by various bee species, including stingless bees. This compound has been shown to exhibit antioxidant, antiproliferative, and antitumor activities. The present study aimed to determine the chemical constituents as well as the antioxidant, cytotoxic, and toxic activities of ethanol extracts of propolis obtained from the stingless bees Scaptotrigona depilis and Melipona quadrifasciata anthidioides, which are found in Brazil. Phytosterols, terpenes, phenolic compounds, and tocopherol were identified in the ethanol extracts of propolis (EEPs) in different concentrations. The compounds stigmasterol, taraxasterol, vanilic acid, caffeic acid, quercetin, luteolin, and apigenin were found only in EEP-M. The EEPs were able to scavenge the free radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and protected human erythrocytes against lipid peroxidation, with the latter effect being demonstrated by their antihemolytic activity and inhibition of malondialdehyde formation. The EEPs showed cytotoxic activity against erythroleukemic cells and necrosis was the main mechanism of death observed. In addition, the concentrations at which the EEPs were cytotoxic were not toxic against Caenorhabditis elegans. In this context, it is concluded that EEP-S and EEP-M show antioxidant and cytotoxic activities and are promising bioactive mixtures for the control of diseases associated with oxidative stress and tumor cell proliferation.Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fed Univ Grande Dourados, Sch Environm & Biol Sci, Dourados, MS, BrazilUniv Estadual Mato Grosso do Sul, Course Chem, Dourados, MS, BrazilUniv Fed Sao Paulo, Dept Biochem, Sao Paulo, SP, BrazilUniv Mogi Das Cruzes, Interdisciplinary Ctr Biochem Invest, Mogi Das Cruzes, SP, BrazilDepartment of Biochemistry, Universidade Federal de São Paulo (UNIFESP), SP, BrazilWeb of Scienc

Composição química, avaliação do potencial antioxidante e toxicidade das folhas de Acrocomia aculeata (Jacq) Lodd. ex. Mart

Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeirosA biodiversidade brasileira representa uma fonte rica de componentes químicos naturais que podem revelar substâncias potencialmente ativas para diversos fins. A importância farmacológica das plantas está relacionada à sua composição química, que fornece propriedades terapêuticas importantes, tais como a atividade antioxidante. A Acrocomia aculeata é uma palmeira nativa do cerrado brasileiro, sua polpa é rica em ácido láurico, β caroteno, e sua amêndoa em ácido oleico. Seu uso medicinal é descrito no tratamento de doenças respiratórias, redução da glicemia e níveis séricos de colesterol, além de possuir propriedades anti-inflamatórias e laxativas, sendo amplamente utilizada na indústria cosmética, alimentícia e na produção de biocombustíveis. Embora os frutos sejam muito utilizados e conhecidos, pouco se sabe sobre as folhas, por conta disto, este estudo objetivou avaliar a composição química, a atividade antioxidante e a toxicidade das folhas de A. aculeata. Para isto, foram produzidos extratos com três diferentes solventes: água (EA-Aa), etanol (EE-Aa) e metanol (EM-Aa). Os extratos foram caracterizados quimicamente através da determinação de compostos fenólicos, flavonoides e taninos, além da análise cromatográfica, seguidos da avaliação da atividade antioxidante dos extratos por métodos de captura de radical livre, DPPH e ABTS. Os EE-Aa e EM-Aa apresentaram maiores quantidades dos metabólitos secundários avaliados e melhores resultados de captura de radicais livres. Porém, no ensaio de proteção contra a hemólise oxidativa e avaliação da peroxidação lipídica em eritrócitos induzidos com AAPH, o EA-Aa apresentou maior proteção em relação aos outros extratos avaliados. Assim, continuamos os ensaios para determinar o efeito protetor de EA-Aa contra a oxidação proteica induzida por AAPH, fragmentação de DNA e a geração de EROS induzidos por H2O2. Um aumento nos níveis de Sirt-1, catalase e ativação de ERK e Nrf2 foram observados em Cos-7 tratadas com EA-Aa, o que também foi observado em nematoides C. elegans, os quais apresentaram maior viabilidade quando induzidos com Juglone e tratados com EA-Aa. A baixa toxicidade de EA-Aa também foi comprovada nos diversos modelos experimentais testados. Em conjunto, os extratos das folhas de A. aculeta apresentaram composição química típica às das plantas, porém a diversidade de compostos presentes em EA-Aa provavelmente está envolvida em sua baixa toxicidade, e seu relevante potencial antioxidante avaliado em diferentes biomoléculas, em células Cos-7 e em C. elegans, provavelmente está relacionado com a ativação da via Sirt1/Nrf2. Desta forma, os resultados obtidos dão suporte para futuros usos de EA-Aa no tratamento de doenças relacionadas com o estresse oxidativo

Hypoglycaemic and Antioxidant Properties of Acrocomia aculeata (Jacq.) Lodd Ex Mart. Extract Are Associated with Better Vascular Function of Type 2 Diabetic Rats

Oxidative stress is involved in the metabolic dysregulation of type 2 diabetes (DM2). Acrocomia aculeata (Aa) fruit pulp has been described for the treatment of several diseases, and recently we have proved that its leaves have phenolic compounds with a marked antioxidant effect. We aimed to assess whether they can improve metabolic, redox and vascular functions in DM2. Control Wistar (W-Ctrl) and non-obese type 2 diabetic Goto–Kakizaki (GK-Ctrl) rats were treated for 30 days with 200 mg.kg−1 aqueous extract of Aa (EA-Aa) (Wistar, W-EA-Aa/GK, GK-EA-Aa). EA-Aa was able to reduce fasting glycaemia and triglycerides of GK-EA-Aa by improving proteins related to glucose and lipid metabolism, such as GLUT-4, PPARγ, AMPK, and IR, when compared to GK-Ctrl. It also improved viability of 3T3-L1 pre-adipocytes exposed by H2O2. EA-Aa also increased the levels of catalase in the aorta and kidney, reduced oxidative stress and increased relaxation of the aorta in GK-treated rats in relation to GK-Ctrl, in addition to the protective effect against oxidative stress in HMVec-D cells. We proved the direct antioxidant potential of the chemical compounds of EA-Aa, the increase in antioxidant defences in a tissue-specific manner and hypoglycaemic properties, improving vascular function in type 2 diabetes. EA-Aa and its constituents may have a therapeutic potential for the treatment of DM2 complications

Gut Metabolism of Sugars: Formation of Glycotoxins and Their Intestinal Absorption

Glycotoxins include the group of advanced glycation end-products (AGEs) and their precursors, most of them highly reactive intermediary compounds of sugar metabolism. Glycotoxins and products of the Maillard reaction are present in high concentrations in foods rich in sugars and processed at high temperatures and are often associated with the flavour of the food. Proteins undergoing this type of molecular modification are targets for gut peptidases and may be absorbed into circulation. AGEs are associated with the toxic effects of glucose in diabetic patients, and some studies have shown that they also contribute to metabolically unhealthy obesity and prediabetes development. Restriction of dietary glycotoxins was shown to improve insulin resistance in humans. However, the real contribution of dietary AGEs to such mechanisms is still not understood. This review summarizes the current knowledge about glycotoxin formation from dietary sugars, their digestion throughout the gastrointestinal system, and the mechanisms of their intestinal absorption

Gut Metabolism of Sugars: Formation of Glycotoxins and Their Intestinal Absorption

Glycotoxins include the group of advanced glycation end-products (AGEs) and their precursors, most of them highly reactive intermediary compounds of sugar metabolism. Glycotoxins and products of the Maillard reaction are present in high concentrations in foods rich in sugars and processed at high temperatures and are often associated with the flavour of the food. Proteins undergoing this type of molecular modification are targets for gut peptidases and may be absorbed into circulation. AGEs are associated with the toxic effects of glucose in diabetic patients, and some studies have shown that they also contribute to metabolically unhealthy obesity and prediabetes development. Restriction of dietary glycotoxins was shown to improve insulin resistance in humans. However, the real contribution of dietary AGEs to such mechanisms is still not understood. This review summarizes the current knowledge about glycotoxin formation from dietary sugars, their digestion throughout the gastrointestinal system, and the mechanisms of their intestinal absorption

Improvement of glycaemia and endothelial function by a new low-dose curcuminoid in an animal model of type 2 diabetes

Curcumin has been suggested as a promising treatment for metabolic diseases, but the high doses required limit its therapeutic use. In this study, a new curcuminoid is synthesised to increase curcumin anti-inflammatory and antioxidant potential and to achieve hypoglycaemic and protective vascular effects in type 2 diabetic rats in a lower dose. In vitro, the anti-inflammatory effect was determined through the Griess reaction, and the antioxidant activity through ABTS and TBARS assays. In vivo, Goto-Kakizaki rats were treated for 2 weeks with the equimolar dose of curcumin (40 mg/kg/day) or curcuminoid (52.4 mg/kg/day). Fasting glycaemia, insulin tolerance, plasma insulin, insulin signalling, serum FFA, endothelial function and several markers of oxidative stress were evaluated. Both compounds presented a significant anti-inflammatory effect. Moreover, the curcuminoid had a marked hypoglycaemic effect, accompanied by higher GLUT4 levels in adipose tissue. Both compounds increased NO-dependent vasorelaxation, but only the curcuminoid exacerbated the response to ascorbic acid, consistent with a higher decrease in vascular oxidative and nitrosative stress. SOD1 and GLO1 levels were increased in EAT and heart, respectively. Altogether, these data suggest that the curcuminoid developed here has more pronounced effects than curcumin in low doses, improving the oxidative stress, endothelial function and glycaemic profile in type 2 diabetes.info:eu-repo/semantics/publishedVersio

Distinct Impact of Natural Sugars from Fruit Juices and Added Sugars on Caloric Intake, Body Weight, Glycaemia, Oxidative Stress and Glycation in Diabetic Rats

Although fruit juices are a natural source of sugars, there is a controversy whether their sugar content has similar harmful effects as beverages’ added-sugars. We aimed to study the role of fruit juice sugars in inducing overweight, hyperglycaemia, glycation and oxidative stress in normal and diabetic animal models. In diabetic Goto-Kakizaki (GK) rats, we compared the effects of four different fruit juices (4-weeks) with sugary solutions having a similar sugar profile and concentration. In vitro, the sugary solutions were more susceptible to AGE formation than fruit juices, also causing higher postprandial glycaemia and lower erythrocytes’ antioxidant capacity in vivo (single intake). In GK rats, ad libitum fruit juice consumption (4-weeks) did not change body weight, glycaemia, oxidative stress nor glycation. Consumption of a matched volume of sugary solutions aggravated fasting glycaemia but had a moderate impact on caloric intake and oxidative stress/glycation markers in tissues of diabetic rats. Ad libitum availability of the same sugary solutions impaired energy balance regulation, leading to higher caloric intake than ad libitum fruit juices and controls, as well as weight gain, fasting hyperglycaemia, insulin intolerance and impaired oxidative stress/glycation markers in several tissues. We demonstrated the distinct role of sugars naturally present in fruit juices and added sugars in energy balance regulation, impairing oxidative stress, glycation and glucose metabolism in an animal model of type 2 diabetes