A abordagem histórico-investigativa no ensino de Ciências

A abordagem Histórico-Investigativa (HI) vem sendo construída ao longo das duas últimas décadas no contexto da busca por caminhos para incentivar motivação, engajamento e argumentação dos alunos em sala de aula. A HI destaca-se por propiciar competências relevantes ao fazer científico, além de tornar os alunos mais ativos e participativos do processo de aprendizagem e contextualizar os conhecimentos escolares. Essa abordagem caracteriza-se pelo uso de atividades experimentais de cunho investigativo, pautadas por episódios históricos, centradas nos alunos e orientadas pelo professor, de modo a criar situações de ensino e aprendizagem que propiciem a reflexão sobre conteúdos específicos da ciência e conteúdos metacientíficos, a prática experimental e a argumentação. Este artigo discute as bases pedagógicas e epistemológicas, objetivos e contribuições da abordagem histórico-investigativa aoEnsino de Ciências.The Historical-Investigative approach (HI) has been built over the last two decades in the context of the search for strategies to encourage students’ motivation, engagement, and argumentation in the classroom. HI provides relevant scientific skills, makes students more active and participatory in the learning process, and contextualizes school knowledge. This approach is characterized by the use of investigative experimental activities, guided by cases from the history of Science. The activities are student- -centered and teacher-oriented, and aim to create teaching and learning situations that foster reflection on specific scientific and meta-scientific contents, experimental practice, and argumentation. This paper discusses the pedagogical and epistemological foundations, objectives and contributions of the historical-investigative approach to Science teaching

Lipopolysaccharide and lipotheicoic acid differentially modulate epididymal cytokine and chemokine profiles and sperm parameters in experimental acute epididymitis

Bacterial infections are the most prevalent etiological factors of epididymitis, a commonly diagnosed inflammatory disease in the investigation of male infertility factors. The influence of early pathogenic mechanisms at play during bacterial epididymitis on reproductive outcomes is little understood. We report here that experimental epididymitis induced in rats by Gram-negative (LPS) and Gram-positive (LTA) bacterial products resulted in differential patterns of acute inflammation in the cauda epididymis. LPS elicited a strong inflammatory reaction, as reflected by upregulation of levels of mRNA for seven inflammatory mediators (Il1b, Tnf, Il6, Ifng, Il10, Nos2 and Nfkbia), and tissue concentration of six cytokines/chemokines (IL1A, IL1B, IL6, IL10, CXCL2 and CCL2) within the first 24 h post-treatment. Conversely, LTA induced downregulation of one (Nfkbia) and upregulation of six (Il1b, Il6, Nos2, Il4 Il10 and Ptgs1) inflammatory gene transcripts, whereas increased the tissue concentration of three cytokines/chemokines (IL10, CXCL2 and CCL2). The stronger acute inflammatory response induced by LPS correlated with a reduction of epididymal sperm count and transit time that occurred at 1, 7, and 15 days post-treatment. Our study provides evidence that early epididymal inflammatory signaling events to bacterial activators of innate immunity may contribute to the detrimental effects of epididymitis upon male fertility.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)CNPqSao Paulo Research Foundation (FAPESP)Pro-Reitoria de Pesquisa/UNESPUniv Fed Sao Paulo, Escola Paulista Med, Sect Expt Endocrinol, Dept Pharmacol, BR-04044020 Sao Paulo, SP, BrazilUniv Estadual Paulista, Dept Pharmacol, Inst Biosci Botucatu, Botucatu, SP, BrazilSci & Innovat Ctr Androl, Androsci, BR-03178200 Sao Paulo, SP, BrazilUniv Sao Paulo, Med Sch, Hosp Clin, Reprod Toxicol Unity,Dept Pathol, BR-01246903 Sao Paulo, SP, BrazilUniv Sao Paulo, Med Sch, Hosp Clin, Div Urol, BR-01246903 Sao Paulo, SP, BrazilState Univ Centro Oeste, Dept Pharm, BR-85040080 Guarapuava, PR, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Sect Expt Endocrinol, Dept Pharmacol, BR-04044020 Sao Paulo, SP, Brazil(CNPq)/CSF/BJT: 401718/2012-3CNPq: 479546/2013-4, 455450/2014-5, 308349/2010-5FAPESP: 2010/52711-0, 2015/08227-0Pro-Reitoria de Pesquisa/UNESP: 557Web of Scienc

Differential regulation of PGC-1α expression in rat liver and skeletal muscle in response to voluntary running

<p>Abstract</p> <p>Background</p> <p>The beneficial actions of exercise training on lipid, glucose and energy metabolism and insulin sensitivity appear to be in part mediated by PGC-1α. Previous studies have shown that spontaneously exercised rats show at rest enhanced responsiveness to exogenous insulin, lower plasma insulin levels and increased skeletal muscle insulin sensitivity. This study was initiated to examine the functional interaction between exercise-induced modulation of skeletal muscle and liver PGC-1α protein expression, whole body insulin sensitivity, and circulating FFA levels as a measure of whole body fatty acid (lipid) metabolism.</p> <p>Methods</p> <p>Two groups of male Wistar rats (2 Mo of age, 188.82 ± 2.77 g BW) were used in this study. One group consisted of control rats placed in standard laboratory cages. Exercising rats were housed individually in cages equipped with running wheels and allowed to run at their own pace for 5 weeks. At the end of exercise training, insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels attained during the continuous infusion of glucose and insulin to each experimental group. Subsequently, soleus and plantaris muscle and liver samples were collected and quantified for PGC-1α protein expression by Western blotting. Collected blood samples were analyzed for glucose, insulin and FFA concentrations.</p> <p>Results</p> <p>Rats housed in the exercise wheel cages demonstrated almost linear increases in running activity with advancing time reaching to maximum value around 4 weeks. On an average, the rats ran a mean (Mean ± SE) of 4.102 ± 0.747 km/day and consumed significantly more food as compared to sedentary controls (<it>P </it>< 0.001) in order to meet their increased caloric requirement. Mean plasma insulin (<it>P </it>< 0.001) and FFA (<it>P </it>< 0.006) concentrations were lower in the exercise-trained rats as compared to sedentary controls. Mean steady state plasma insulin (SSPI) and glucose (SSPG) concentrations were not significantly different in sedentary control rats as compared to exercise-trained animals. Plantaris PGC-1α protein expression increased significantly from a 1.11 ± 0.12 in the sedentary rats to 1.74 ± 0.09 in exercising rats (<it>P </it>< 0.001). However, exercise had no effect on PGC-1α protein content in either soleus muscle or liver tissue. These results indicate that exercise training selectively up regulates the PGC-1α protein expression in high-oxidative fast skeletal muscle type such as plantaris muscle.</p> <p>Conclusion</p> <p>These data suggest that PGC-1α most likely plays a restricted role in exercise-mediated improvements in insulin resistance (sensitivity) and lowering of circulating FFA levels.</p

Rhinovirus C and Respiratory Exacerbations in Children with Cystic Fibrosis

To investigate a possible role for human rhinovirus C in respiratory exacerbations of children with cystic fibrosis, we conducted microbiologic testing on respiratory specimens from 103 such patients in São Paulo, Brazil, during 2006–2007. A significant association was found between the presence of human rhinovirus C and respiratory exacerbations

An unusual T-cell childhood acute lymphoblastic leukemia harboring a yet unreported near-tetraploid karyotype

<p>Abstract</p> <p>Background</p> <p>Near-tetraploid (model #81-103) and near-triploid (model #67-81) karyotypes are found in around 1% of childhood acute lymphoblastic leukemia. Due to its rarity, these two cytogenetic subgroups are generally included in the hyperdiploid group (model # > 51). Therefore separate informations about these two subgroups are limited to a few reports. Some studies found that near-tetraploidy is relatively more frequent in higher median ages and it is associated to Frech-American-British Classification subtype L2. Although the mechanisms by which leukemic blast cells divide is still unclear, studies have suggested that hyperdiploidy, near-triploidy and near-tetraploidy do not seem to share the same mechanism.</p> <p>Findings</p> <p>Herewith, we present a new childhood T-acute lymphoblastic leukemia case of near-tetraploid karyotype with loss of two p53-gene copies, characterized in detail by cytogenetic and molecular studies.</p> <p>Conclusion</p> <p>We suggest that p53 is a good target gene to be screened, once p53 is one of the main effectors of cell cycle checkpoints.</p

Production of xylooligosaccharides from Brazilian Syrah grape pomace flour

BACKGROUND: The aim of this work was to determine the most favorable conditions for the production of xylooligosaccharides (XOS) from Brazilian Syrah grape pomace. Chemical processes were performed using a rotatable central composite design, where the concentration of sulfuric acid or concentration of sodium hydroxide and grape pomace flour: solvent mass ratio were the dependent variables. Enzymatic production was also evaluated using xylanase produced by Aspergillus niger 3T5B8 and Viscozyme® enzymatic commercial cocktail. RESULTS: Chemical extraction allowed to recover 21.8 to 74.6% and 5.2 to 96.3% of total XOS for acid and alkaline processes, respectively. Enzymatic production using xylanase extracted up to 88.68 ± 0.12% of total XOS and up to 84.09 ± 2.40% with Viscozyme®. CONCLUSION: The present study demonstrated different feasible methods to produce high added value molecules, the xylooligosaccharides, from Syrah grape pomace flour, valorizing this major by‐product. The use of enzymatic cocktails demonstrated to be an alternative to the conventional methods, allowing to obtain an eco‐friendly and sustainable grape pomace extract.info:eu-repo/semantics/acceptedVersio

Dietary Acid Load: A Novel Nutritional Target in Overweight/Obese Children with Asthma?

Obesity has been repeatedly linked to asthma, and several potential mechanisms have been proposed in the etiologies of the obese-asthma phenotype. Considering that lungs play an important role in systemic pH and acidbase regulation, are a key organ in asthma development, and that nutritional inadequacy of several nutrients and high dietary acid load can affect airway inflammation and reactivity, we aimed to test the hypothesis that dietary acid load may be associated with asthma in children. Data on 699 children (52% females), aged 712 years, were analyzed. Anthropometric measurements were performed to assess body mass index. Dietary acid load was calculated using potential renal acid load (PRAL) equations from a 24 h dietary recall administrated to children. Adjusted PRAL for total energy intake was applied with the use of the residual method. Lung function and airway reversibility were assessed with spirometry. Asthma was defined by a positive bronchodilation or self-reported medical diagnosis with reported symptoms (wheezing, dyspnea, or dry cough) in the past 12 months. After adjustment for energy intake, sex, age, parents education level, and physical activity, positive and significant associations were found between asthma and PRAL [odds ratio (OR) = 1.953, 95% CI = 1.024, 3.730) in overweight/obese children. Our findings suggest that dietary acid load might be a possible mechanism in overweight/obese-asthma phenotype development.</jats:p