969 resultados para Raphidocelis subcapitata : Toxicidade


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Pós-graduação em Ciência e Tecnologia Animal - FEIS

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A epilepsia é a doença neurológica maiscomum em seres humanos e cães, possui diversas etiologias e é classificada em epilepsia primária, idiopática ou hereditária e epilepsia secundária ou adquirida. A maioria dos cães epiléticos é tratada com fármacos antiepiléticos padrões, fenobarbital e/ou brometo de potássio, com os quais obtém-se sucesso; porém, cerca de 20-30% dos cães tratados necessitam de terapia adicional, pois não respondem a terapia padrão. Os medicamentos utilizados como anticonvulsivantes levam a efeitos de toxicidade e menos de 50% dos cães com epilepsia permanecem livres de convulsões sem efeitos secundários das medicações. Novas alternativas terapêuticas têm sido utilizadas. Dentre elas, a Gabapentina que é um medicamento análogo ao GABA e possui diferentes mecanismos de ação, tem efeito dose-dependente, absorção saturada, não tem ligação às proteínas plasmáticas e, ao contrário da maioria das medicações anticonvulsivas, possui eliminação renal. Quando sua eficácia é comprovada em associação às drogas anticonvulsivas padrões, é possível a redução da dose das mesmas evitando ou minimizando assim os desagradáveis efeitos secundários destas medicações. Por esses motivos, o objetivo desse trabalho é averiguar a eficácia da Gabapentina quando associada aos fármacos padrões utilizados na terapia antiepilética. Para tanto, foi realizado um levantamento bibliográfico em cinco bases de dados eletrônicos. Foram obtidos 13 artigos, os quais, após serem analisados, permitiram concluir que a Gabapentina apresenta resultados significativamente satisfatórios no tratamento da epilepsia idiopática em cães refratários ao tratamento padrão; porém, mais estudos em cães não devem ser descartados de modo a melhor elucidar esses efeitos

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Stryphnodendron obovatum Benth. known as barbatimão de folha miúda, is a typical tree of the Midwest and Southeast “Cerrado” regions of Brazil. Several secondary metabolites have been identified in its barks, including tannins, described on the literature as allelochemicals. Beholding to identify a possible allelopathic activity in S. obovatum leaves, we tested hydroethanolic EtOH:H2 O (70% and 50% v/v) extracts, in different concentrations, on the initial development of cucumber (Cucumis sativus L.). Among the results, we highlight the effect of the 50% hydroethanolic extract in inhibiting the formation of the main and the secondary roots and the stimulation of the hypocotyl growth in C. sativus by the 70% hydroethanolic extract, both in all concentrations tested. The cytotoxic activity, evaluated by bioassay toxicity on Artemia salina Leach., was negative for the tested extracts (LC50> 1000 mg.mL-1). Concomitantly, the molluscicidal activity, evaluated against snails of Biomphalaria glabrata Say, presented low acute toxicity of solutions of 70% hydroethanolic extract at concentrations of 128.9 mg.mL-1 and 172.8 mg.mL-1 and values above 250 mg.mL-1 to solutions of 50% hydroalcoholic extract, being therefore considered inactive for these. The results suggest the existence of allelochemicals in the extracts tested and they have low toxicity.

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In view of the diversity of environments found in the Brazilian territory, it is understandable that the use of native species can provide more relevant information for ecotoxicological studies. The purpose of this work was to evaluate the quality of water samples from the Atibaia River in an area that is under the influence of petroleum refinery using a native test-organism and submitting the data to PCA statistical analysis. Therefore, acute toxicity assays with Lecane bulla (Rotifera) were performed in four locations of the river, as well as physical-chemical analyses. Sampling was drawn in the dry and rainy seasons. The bioassays were static and lasted 48 hours; dead organisms were quantified at the end of the tests. Toxicological differences among the samples/per location and control were compared by means of the Analysis of Variance. Physical-chemical and mortality variables were simultaneously analyzed by multivariate analysis of the principal components and the Pearson correlation coefficient. Water samples from the exit of the refinery stabilization pond (location S.1) were toxic to L. bulla in both seasons, with significant differences in relation to the control and between the seasons. The statistical treatment of data showed that mortality was strong and positively correlated with total hardness, chlorides and EC, which together with pH presented higher values in location S.1, in the dry and in the rainy seasons. Due to its sensibility to the quality of the Atibaia river water samples, the potential use of L. bulla for ecotoxicological studies as an alternative test organism could be demonstrated.

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Guava (Psidium guajava L.) is a plant often employed in popular medicine. Recently several studies have alerted about the toxicity of substances present in medicinal plants, which can pose risks to the human health. In this sense, the present work aimed to investigate the phytotoxic, cytotoxic and genotoxic action of three guava varieties - Paluma, Pedro Sato and Roxa (purple) - on the plant test system Lactuca sativa L. Thus, macro- and microscopic evaluations were carried out for five infusion concentrations (2.5, 5.0, 10.0, 20.0 and 40.0 g.L-1) prepared from each variety. Distilled water was used as negative control. Chromatographic and spectroscopic analysis by HPLC-PAD indicated that the chemical composition of the infusion of Roxa is different than that of the infusions of the varieties Paluma and Pedro Sato. It was observed that seed germination and root growth in L. sativa exposed to infusions decreased with increasing infusion concentration, regardless of the tested cultivar. For the mitotic index, no statistical differences were observed. On the other hand, a significant increase in the frequency of cell cycle alterations was verified, especially for the highest concentrations tested. The cytogenotoxic was significant. Therefore, guava should not be used indiscriminately in popular medicine.

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Pós-graduação em Química - IBILCE

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Pós-graduação em Engenharia Mecânica - FEG

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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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the aims of this study were to determine imazapyr efficacy for floating macrophyte control and ecotoxicology for non-target organisms. For the floating macrophyte control efficacy tests were used the doses of 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 and 4,0 L ha(-1) and a control with 10 replicates. The acute toxicology for non-target organisms was estimated by lethal concentration 50% (LC50 and EC50). The floating macrophyte control efficacy was over 90%. Imazapyr was classified as moderately toxic for the following biomarkers: L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata, and P. mesopotamicus and lightly toxic for A. caroliniana. Thus, imazapyr herbicide is a tool with great potential to be used on floating macrophyte control (E. crassipes, P. stratiotes e S. molesta) in Brazil and this practice can be evaluated by the use of application biomarkers.

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The aims of this research were to evaluate the acute toxicity (LC/EC50) and the environmental risk of toltrazuril (TOL) and florfenicol (FFC) for plant Lemna minor, snail Pomacea canalicuta, fish Piaractus mesopotamicus and Hyphessobrycon eques and the microcrustacean Daphnia magna. The organisms were acclimated in room bioassay with controlled temperature according to standard to each one. They were exposed at nominal concentrations in static system. For environmental risk (RQ) was used the estimated environmental concentration (EEC) that is the dosage indicate to treatment and the lethal or effective concentration (LC/CE50) from each drug in acute exposure. FFC showed LC50;7d of 97.03 mg L-1 for L. minor; >100.0 mg L-1 for P. mesopotamicus and H. eques and EC50;48h > 100.0 mg L-1 for P. canaliculata and D. magna, and it was classified low risk (RQ = 0.01) for all bioindicators. TOL howed LC50;7d >100.0 mg L-1 for L. minor, 3.72 mg L-1 for P. mesopotamicus; 6.22 mg L-1 for H. eques and CE50;48h of 7.59 mg L-1 for P. canaliculata and 18.57 mg L-1 for D. magna, and it was classified low risk (RQ = 0.01) for L. minor and high risk for P. mesopotamicus (RQ = 2.68), H. eques (RQ = 6.22), P. canaliculata (RQ = 1.31) and D. magna (RQ = 0.53). Lemna minor was the bioindicator indicating of FFC toxicity and H. eques, bioindicator of the TOL. FFC is safety however and the use of TOL necessaries cautions to treat the wastewater before discard on the environment.