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Acute Toxicity Test with Daphnia magna: An Alternative to Mammals in the Prescreening of Chemical Toxicity?

Guilhermino, Lúcia; Diamantino, Teresa; Silva, M. Carolina; Soares, A. M. V. M.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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In this study, the association between the acute toxicity of 15 compounds to Daphnia magna, expressed as 24- and 48-h LC50 values, and the corresponding oral LD50 values for the rat was tested. Since there was evidence of a strong relationship between the two species, the sample was extended to 54 cases by including the values for acute toxicity to D. magna and rat of more chemicals published by other authors. Thus, a total of 54 data points were further used to ascertain the relationship between the acute toxicity of chemical compounds to D. magna and that to the rat. To summarize its validity, the D. magna test is more specific than sensitive as an indicator of toxicity to the rat. When it is used with a chemical that has a high probability of being very toxic to D. magna (LC50< 0.22 mg/L), the test provides considerable information if it is positive, virtually giving evidence of toxicity to the rat (with a probability of 0.83). On the other hand, a negative test (D. magna LC50>0.22 mg/L) has a probability of correctly assigning nontoxicity to the rat equal to 0.74. This study and results published by other authors provide good evidence of the applicability of using invertebrate tests as prescreening methods, thus considerably reducing the number of mammals required in toxicity testing.; http://www.sciencedirect.com/science/article/B6WDM-45F556G-25/1/121bce1063111e232b88e96d482edccd

The effect of silver nanoparticles: a chronic in vivo study for the evaluation of hepatic mitochondrial toxicity

Silva, Rui Gonçalo Teixeira da
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Dissertação de Mestrado
ENG
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Manufactured nanomaterials have been of extreme importance due to the beneficial physicochemical properties they possess compared to bulk parental materials. However, the properties that make them so attractive are also the same that can cause harm both to humans and environment. Over the last years there has been a rapid development of the nanotechnology industry and the inevitable human exposure tends rapidly to expand, accompanied by potential for adverse health effects. Among all used nanoparticles (NPs), silver nanoparticles (AgNPs) have the highest level of commercialization. Silver has been used for decades in medical healthcare due to its known antibacterial properties. One can also observe AgNPs in products used daily such as cosmetics, lotions, toothpastes, soaps, sunscreen, clothing and electronics. Over the last years, nanoparticles have been the subject of intense research for use in biomedicine, namely as biosensors, drug-delivery agents and imaging contrast agents, which take advantage of their unique optical properties. Human exposure to AgNPs can occur through different ways: inhalation, ingestion, injection and dermal contact. As a major organ of detoxification, the liver is one of the most important targets after AgNPs exposure. The main toxicological concern is the fact that AgNPs preferentially accumulate in mitochondria. Since mitochondria have an essential bioenergetic function...

Structure activity relationship, acute toxicity and cytotoxicity of antimycobacterial neolignan analogues

SOUZA, Ana Olivia de; ALDERETE, Joel Bernabe; MINARINI, Paulo Roberto Regazi; MELO, Patricia da Silva; FERREIRA, Iasmin; BARATA, Lauro Euclides Soares; SILVA, Celio Lopes
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
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Objectives The study`s aims were to evaluate the antimycobacterial activity of 13 synthetic neolignan analogues and to perform structure activity relationship analysis (SAR). The cytotoxicity of the compound 2-phenoxy-1-phenylethanone (LS-2, 1) in mammalian cells, such as the acute toxicity in mice, was also evaluated. Methods The extra and intracellular antimycobacterial activity was evaluated on Mycobacterium tuberculosis H37Rv. Cytotoxicity studies were performed using V79 cells, J774 macrophages and rat hepatocytes. Additionally, the in-vivo acute toxicity was tested in mice. The SAR analysis was performed by Principal Component Analysis (PCA). Key findings Among the 13 analogues tested, LS-2 (1) was the most effective, showing promising antimycobacterial activity and very low cytotoxicity in V79 cells and in J774 macrophages, while no toxicity was observed in rat hepatocytes. The selectivity index (SI) of LS-2 (1) was 91 and the calculated LD50 was 1870 mg/kg, highlighting the very low toxicity in mice. SAR analysis showed that the highest electrophilicity and the lowest molar volume are physical-chemical characteristics important for the antimycobacterial activity of the LS-2 (1). Conclusions LS-2 (1) showed promising antimycobacterial activity and very weak cytotoxicity in cell culture...

Interações entre micorriza arbuscular, rizobactérias, fósforo e silicio na manifestação da toxidez de manganês em soja.; Interactions among arbuscular mycorrhiza, rhizobacteria, phosphorus and silicon on manganese toxicity display in soybean.

Nogueira, Marco Antonio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 23/01/2002 PT
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A atenuação da toxidez de Mn é relativamente freqüente em plantas micorrizadas. Nesse trabalho, testaram-se três hipóteses para avaliar os efeitos da micorrização sobre a manifestação da toxidez de Mn: 1) A micorrização altera a comunidade microbiana oxidante e redutora de Mn no solo, o que reflete na sua disponibilidade; 2) A micorrização propicia maior absorção de Si pela planta, o qual atenua a toxidez de Mn; 3) O maior desenvolvimento das plantas micorrizadas atenua a toxidez de Mn pelo efeito diluição. Conduziram-se cinco experimentos, empregando-se a cultivar de soja IAC-8 e, como substrato, solos classificados como NEOSSOLO QUARTZARÊNICO típico ou NITOSSOLO VERMELHO Eutroférrico típico, autoclavados para eliminar a comunidade microbiana nativa. Num experimento preliminar foi selecionada a espécie de fungo micorrízico arbuscular (FMA) G. etunicatum, eficiente em promover o crescimento da soja nos dois solos, com efeitos mais evidentes entre 9 e 12 semanas. Nesse experimento, a espécie G. macrocarpum no substrato argiloso agravou os sintomas de toxidez de Mn e foi utilizada nos experimentos posteriores para se investigar esse comportamento. No segundo experimento, G. etunicatum atenuou a toxidez de Mn em plantas que receberam doses crescentes de Mn no substrato...

Estudo da qualidade do sedimento através de teste de toxicidade e marcadores de esgoto na Enseada de Ubatuba-SP, Brasil. Influência do aumento da população de veraneio; Study of sediment quality through toxicity tests and sewage markers at Ybatuba Small Bay-SP, Brazil, influenced by increasing population in summer holidays

Oliveira, Luis Fabiano Joaquim de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/10/2009 PT
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Este estudo teve como objetivo avaliar a toxicidade do sedimento da Enseada de Ubatuba através de testes de toxicidade, utilizando-se fase aquosa e sedimento total antes e depois do aumento da população de veraneio e a contaminação por esgoto urbano. Realizaram-se testes de toxicidade com a água intersticial e interface água/sedimento e larvas de L. variegatus. No testes com sedimento total utilizou-se anfípodo T. viscana. Utilizaram-se as análises de esteróis fecais para verificar a contaminação por esgoto. Foram coletadas em 17 estações. Uma estação do canto direito da Praia do Itaguá foi a única que obteve toxicidade nos três testes na campanha após o aumento da população de veraneio. Para os testes com a fase aquosa, uma estação próxima ao Instituto de Pesca e duas na Praia do Perequê-Açú foram tóxicas nas duas campanhas. Apresentaram contaminação por esgoto e toxicidade para os testes de fase aquosa três estações do canto direito da Praia do Itaguá, uma próxima ao Rio Acaraú, outra em frente ao Rio Grande e também uma na Praia do Perequê-Açú. Uma estação próxima a saída do Rio Grande apresentou indício de contaminação por esgoto, mas não obteve toxicidade na fase aquosa. O aumento da população de veraneio mostrou uma maior toxicidade para os testes com a fase aquosa e uma diminuição do número de sobreviventes de anfípodos. A Enseada de Ubatuba apresentou toxicidade nos testes com fase aquosa em quase todas as estações após o aumento da população...

Toxicidade aguda e subaguda do radiofármaco 18F-FDG; Acute and subacute toxicity of 18F-FDG

Dantas, Danielle Maia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/09/2013 PT
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Antes de se iniciar os estudos clínicos de uma nova droga, é necessário realizar uma bateria de testes de segurança, para avaliar o risco humano. Os radiofármacos como qualquer outra nova droga, devem ser testados levando em conta sua especificidade, duração de tratamento e principalmente a toxicidade de ambas as partes, a molécula não marcada e a sua radioatividade em si, além das impurezas provindas da radiólise. Órgãos regulatórios como o Food and Drug Administration-EUA (FDA) e a Agência de Medicina Européia (EMEA), estabelecem guias para a regulamentação de produção e pesquisas de radiofármacos, No Brasil a produção de radiofármacos não era regulamentada até o final de 2009, quando foram estabelecidas pela Agência Nacional de Vigilância Sanitária (ANVISA) as resoluções nº 63, que visa as Boas Práticas de Fabricação de Radiofármacos e a nº 64 que visa o registro do radiofámaco. Para a obtenção do registro de radiofármacos são necessárias a comprovação da qualidade, segurança, eficácia e especificidade do medicamento. Para a segurança dos radiofármacos devem ser apresentados estudos de toxicidade aguda, subaguda e crônica como também a toxicidade reprodutiva, mutagênica e carcinogênica. Hoje o IPEN-CNEN/SP produz um dos radiofámacos mais importantes da medicina nuclear...

Avaliação ecotoxicológica e Identificação da Toxicidade no ribeirão Pires, Limeira - SP; Ecotoxicological assessment and Identification of Toxicity in stream Pires, Limeira - SP

Régis Fernando Spadotim
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/02/2015 PT
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O ribeirão Pires é o principal afluente do ribeirão Pinhal, manancial utilizado na captação de águas para distribuição à população de Limeira, SP. Estudos anteriores realizados na micro bacia do ribeirão Pinhal apontaram toxidade aguda apenas nas águas do ribeirão Pires, para o organismo-teste Ceriodaphnia dubia. Desta forma torna-se importante conhecer as fontes de contaminação, bem como seus contaminantes para assegurar água de qualidade para o município. No presente trabalho realizou-se a avaliação ecotoxicológica mediante testes de toxidade aguda e crônica de amostras de água superficial coletadas no ribeirão Pires, e identificação da toxidade utilizando o estudo de Avaliação e Identificação da Toxidade (AIT). O princípio desse método baseia-se no fracionamento das amostras por meio de uma série de processos físicos e químicos, objetivando eliminar ou separar grupos de compostos para verificação de seu potencial tóxico. Para realização do AIT utilizou-se os organismos-testes Ceriodaphnia dubia e Daphnia similis, mediante testes de toxidade aguda, após a manipulação das amostras verificou-se a redução significativa da toxicidade com tratamento em coluna C18 em pH 9 e quelação com EDTA. Estes tratamentos de AIT (Fase I) apontaram respectivamente...

Assessment of the acute toxicity of eutrophic sediments after the addition of calcium nitrate (Ibirité reservoir, Minas Gerais-SE Brazil): initial laboratory experiments

Janke,H.; Yamada,TM.; Beraldo,DAS.; Botta,CMR.; Nascimento,MRL.; Mozeto,AA.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2011 EN
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This study evaluated the acute toxicity of sediment in a eutrophic reservoir after remediation with a calcium nitrate solution to retain phosphorus. The study involved microcosms of surface sediments and water from the sediment-water interface in the Ibirité reservoir. This reservoir, located in the vicinity of metropolitan Belo Horizonte (Minas Gerais, SE Brazil), is a water body that receives treated effluents from an oil refinery (REGAP-Petrobras), as well as high loads of untreated urban effluents from the city of Ibirité and surrounding areas and industrial effluents from a major industrial park. Incubation times of the treatment experiments were: t = 0, t = 5, t = 10, t = 25, t = 50, t = 85 and t = 135 days. One control microcosm and three treated microcosms were analysed in each time interval. Acute toxicity of water samples was assessed with Ceriodaphnia silvestrii Daday, 1902 and that of bulk sediment samples with Chironomus xanthus Rempel, 1939. Toxicity tests were carried out concomitantly with chemical analyses of dissolved inorganic nitrogen species (ammonia, nitrate and nitrite), sulfate and metals in the water samples of the microcosms. Acid volatile sulfides (AVS), simultaneously extracted metal (SEM) and potentially bioavailable metal were analyzed in bulk sediment samples. Neither of the tested organisms showed toxicity in the control microcosm samples. The water column of the treated microcosm showed toxicity to C. silvestrii...

Methods of acute biological assays in guinea-pigs for the study of toxicity and innocuity of drugs and chemicals

Ko,Gui Mi; Rosenkranz,Adela; Bertoncini,Clélia Rejane Antonio; Jurkiewicz,Neide Hyppolito; Franco,Mirian Ghiraldini; Jurkiewicz,Aron
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
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In this study, 602 samples were tested by the following assays performed at the animal facilities (Cedeme) of the Federal University of São Paulo (UNIFESP): 385 for dermal irritability, 90 for ocular irritability (discontinued in 1995), 31 for systemic toxicity by injection, 26 for oral acute toxicity, 15 for toxicity by intracutaneous injection, 15 for skin sensitization, 15 for toxicity of serum and vaccines for human use, 14 for toxicity by intramuscular implantation, 7 for pyrogens, 2 for acute dermal toxicity, and 2 for irritation of mucous membrane. The following agents were tested: cosmetics and related substances (42.0%), chemicals used in industry (32.9%), plastics, rubber, and other polymers (15.9%), agrotoxics (4.0%), medicines (2.7%), and vaccines (2.5%). In the present description, emphasis was given to tests of dermal irritability and sensitization. This work was conducted entirely in animal facilities, according to our general belief that animal facilities at universities, while considering ethic principles and sanitary, genetic, nutritional, and pathophysiological controls, also require laboratories specialized in areas such as transgenics, cryopreservation, ambiental physiology, functional genomics, alternative models...

Manejo da irriga????o por alagamento e a toxidez por ferro no arroz cultivado em casa de vegeta????o.; Flooding management and iron toxicity on rice cultivaded in greenhouse.

SCHMIDT, Fabiana
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Solos; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-Gradua????o em Solos; UFPel; BR
Tipo: Dissertação Formato: application/pdf
POR
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Iron toxicity is one of the most important abiotic stresses limiting rice production in lowland systems. Soil flooding affects the gas exchange processes with the atmosphere promoting oxi-reduction conditions in rice fields. The oxi-reduction state of the soil is influenced by anaerobic microorganism activities, which is affected by water management. With the objective of evaluating the effect of different water management systems on iron reduction dynamics in flooded Albaqualf Soil and to iron toxicity symptoms in irrigated rice plants. The experiment was performed in the greenhouse using a randomized complete block design with four replications. The water management treatments were: 1. Beginning of flooding in the stage V2-V3 (Condition 1); 2. Beginning of flooding in the stage V6-V7 (Condition 2); 3. Condition 1 and drainage in the stage V10-V11; 4. Condition 2 and drainage in the stage V10- V11 and 5. Condition 1 and drainages in the stage V8-V9 and V10-V11. Was sampled the soil solution weekly at 17, 24, 31, 41, 48, 55, 63 and 70 days after the emergence of the rice plants. In the soil solution the Eh, pH, and the concentration of Fe, Mn, Ca, Mg, P and K were evaluated. In the rice plants the shoot dry matter and the concentrations of the following nutrients: N...

Assessing the toxicity of PAHs singly and in mixtures to Japanese medaka (Oryzias latipes)

Waters, Helen
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN
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Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants that are released into the environment as a result of natural sources and anthropogenic activities. PAHs are of particular concern because they cause dioxin-like toxicity to the early life stages of fish and threaten recruitment in multiple fish species. This study investigated whether PAH toxicity is mediated by AHR binding by assessing the toxicity of single compounds classified as strong and weak inducers of cytochrome P4501A (CYP1A) enzymes, which may play a role in toxicity. Due to the potential for PAHs to interact in mixtures, this study also investigated the toxicity of mixtures of different combinations of PAHs depending on their potency for induction of CYP1A. The compounds selected were two strong inducers of CYP1A, β-napthoflavone (BNF) and 7-isopropyl-1-methylphenanthrene (retene), and two weak inducers of CYP1A, 2-ethylphenanthrene (2EP) and 9-ethyl-10-methylphenanthrene (9E10MP). The toxic unit (TU) approach was used to evaluate the toxicity of mixtures of the PAHs using toxicity data from bioassays of the individual PAHs. Toxicity tests were conducted on the early life stages of Japanese medaka (Oryzias latipes). In single compound bioassays...

The transcripted response of barley (Hordeum vulgare L.) to boron toxicity.

Hassan, Mahmood
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
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The occurrence of Boron (B) toxicity in Australian soils is recognised as a limiting factor for cereal productivity. A number of loci conferring tolerance to B toxicity have been identified in barley and chromosomally mapped. However, a lack of knowledge relating to the physiological and molecular events that occur under B toxicity and the molecular basis for B stress tolerance has been a bottleneck in harnessing available genetic diversity in barley and wheat. The recent advances in functional genomics provided an opportunity to examine B stress in barley in more detail. The aim of this project was to analyse genes differentially expressed under B stress in tolerant and intolerant barley to identify candidate genes involved in B toxicity tolerance. Two experimental approaches, Suppression Subtractive Hybridization (SSH) and microarray were adopted. Firstly, SSH was performed to examine gene expression in roots of selected tolerant and intolerant doubled haploid lines from a Clipper (B intolerant) X Sahara 3771 (B tolerant) mapping population, grown under moderate B stress. The SSH experiment aimed to investigate the early transcriptional response of B tolerant barley lines to B stress in order to identify the basis for B toxicity tolerance in roots. Differential screening of the subtracted library generated from B treated plants identified a total of 111 non-redundant clones up-regulated in bulked tolerant lines. On the other hand 94 clones were differentially expressed under non-treated conditions. Among the clones identified from subtracted library generated from B treated plants...

Avaliação ecotoxicológica de sedimentos em reservatórios da bacia do rio Tietê, SP, com ênfase na aplicação do estudo de AIT - Avaliação e Identificação da Toxicidade; Ecotoxicological evaluation of sediments in reservoirs of the Tietê river basin SP, with emphasis on the application of the TIE approach - Toxicity Identification and Evaluation

Paschoal, Clarice Maria Rispoli Botta
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/09/2002 PT
Relevância na Pesquisa
36.51%
A avaliação ecotoxicológica dos sedimentos dos reservatórios de Barra Bonita e Salto Grande foi realizada através de testes de toxicidade aguda e crônica com o sedimento total e o solubilizado, com os organismos-teste Chironomus xanthus, Daphnia similis, Ceriodaphnia dubia, Vibrio fisheri e Spirillum volutans, além de análises físicas (pH, EH e 'O IND.2') e químicas (fósforo, nitrogênio, carbono orgânico total, sulfetos e amônia e metais potencialmente disponíveis). A concentrações médias de matéria orgânica e fósforo obtidas para os sedimentos dos reservatórios de Barra Bonita e Salto Grande foram elevadas, e condizentes com a carga de matéria orgânica e com as baixas concentrações de oxigênio dissolvido e de potencial redox. Em relação aos metais, os resultados revelaram que, para o reservatório de Barra Bonita, eles podem estar influenciando a toxicidade detectada através dos testes de toxicidade. Em Salto Grande, os resultados indicaram que os sulfetos estão atuando como fase controladora dos metais, mantendo-os indisponíveis nos sedimentos. Para esse reservatório a principal causa da toxicidade foi a acidez. O estudo de Avaliação e Identificação da Toxicidade realizado com as amostras de sedimento dos reservatórios de Barra Bonita...

Priorização de fármacos em água destinada ao consumo humano baseada em avaliação da toxicidade e do comportamento ambiental por  meio de modelos computacionais (in silico) para fins de gestão ambiental; Prioritization of pharmaceuticals in water intended for human consumption based on toxicity and environmental fate assessment by in silico models for environmental management purposes

Santos, Carlos Eduardo Matos dos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/04/2015 PT
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Introdução: É cada vez mais preocupante a escassez de água e a qualidade dos recursos hídricos. Nas últimas décadas diversos estudos têm apontado a presença de fármacos em água destinada ao consumo humano, caracterizando a existência de rotas de exposição que podem representar riscos para a saúde humana e meio ambiente. Devido a escassez de dados sobre o comportamento ambiental e toxicidade na exposição crônica a baixas doses a fármacos, sua ocorrência em água é uma preocupação para comunidade científica, reguladores e população. Diversos estudos recentes têm sugerido critérios para a definição de fármacos prioritários, ou seja, abordagens com componentes ou fatores que atribuem grau de relevância aos contaminantes. Devido aos altos custos e necessidade de testes adicionais, uma das alternativas propostas para avaliação do comportamento ambiental e toxicidade têm sido os modelos in silico. Objetivos: Estudar o comportamento ambiental e o potencial de toxicidade de ingredientes farmacêuticos ativos(IFAs) para fins de identificação de contaminantes prioritários por meio da aplicação de ferramentas computacionais e modelos in silico. Métodos: Foram selecionados fármacos considerados relevantes para o Brasil conforme critérios de inclusão específicos. Para os fármacos selecionados...

The mechanism of retene toxicity in the early life stages of fish

Scott, Jason
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 6295278 bytes; application/pdf
EN; EN
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36.55%
Alkylphenanthrenes such as retene (7-isopropyl-1-methylphenanthrene) are aquatic contaminants commonly found in anthropogenically-, industrially-, and petroleum-contaminated environments, and have been implicated in crude oil toxicity. In the early life stages (ELS) of fish, exposures to alkylphenanthrenes produce signs of toxicity typical of those observed in exposures to halogenated aromatic hydrocarbons, particularly to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD, the most toxic congener, serves as the basis of the current mechanism-based risk assessment model. The model assumes that congeners that produce TCDD-like toxicity share a common mode of action and act additively. The mechanism of TCDD-like toxicity is assumed to be mediated by the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor involved in the xenobiotic response (e.g., induction of cytochrome P450 1A enzymes; CYP1A) and in normal development. CYP1A enzymes are not involved in the mechanism of TCDD toxicity. Alkylphenanthrenes toxic to the ELS of fish are AhR ligands, but in contrast to TCDD, are readily metabolized by CYP1A enzymes. The byproducts of CYP1A metabolism have been implicated in retene toxicity. However, the target tissue of retene and the direct roles of AhR and CYP1A in retene toxicity are unknown...

The toxicity of alkyl-chrysenes and benz[a]anthracenes to embryonic fish

Lin, HONGKANG
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.54%
Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are major constituents of crude oil, and the 3-5 ringed alkyl-PAHs have been identified as the main components chronically toxic to fish. While chysene homologues have higher cytochrome P4501A (CYP1A) induction potencies than alkyl-phenanthrenes, there is little characterization of toxicity for 4-ringed alkyl PAHs. This study measured the chronic toxicity of chrysene, benz[α]anthracene, and some alkylated congeners to the embryos of Japanese medaka (Oryzias latipes) using the partition-controlled delivery method (PCD) of exposure. This exposure method relies on the partitioning of chemicals from polydimethylsiloxane (PDMS) films, loaded with various concentrations of test chemical, to embryo rearing solutions. The objectives of this thesis were: (1) to further characterize the PCD method with a series of 4-ringed PAHs; (2) to evaluate the effects of different chemical structures on the toxicity of test compounds; and (3) to extend structure toxicity relationships from alkyl-phenanthrenes. The PCD method generated a gradient of aqueous concentrations for test compounds, and these exposure concentrations were maintained constant for the 17-day period. Benz[α]anthracene showed higher toxicity than chrysene. Toxicity increased with the degree of alkylation on the ring structures...

European ring exercise on water toxicity using different bioluminescence inhibition tests based on Vibrio fischeri, in support to the implementation of the water framework directive

Farré Urgell, Marinel.la; Martínez, Elena; Hernando, María Dolores; Fernández Alba, Amadeo R.; Fritz, Johann; Unruh, Eckehardt; Mihail, Otilia; Sakkas, Vasilis; Morbey, Ana; Albanis, Triantafyllos; Brito, Fatima; Hansen, Peter-Diedrich; Barceló, Dami
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
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11 pages, 6 figures, 6 tables.-- PMID: 18970570 [PubMed].-- Available online Nov 14, 2005.-- Issue title: "1st Swift-WFD workshop on validation of Robustness of sensors and bioassays for Screening Pollutants" (Maó, Menorca, Dec 2-3, 2004).; An inter-laboratory comparison exercise was conducted under the European Union funded project entitled: Screening Methods for Water Data Information in Support of the Implementation of the Water Framework Directive (SWIFT-WFD) and coordinated by the Consejo Superior de Investigaciones Científicas (CSIC), in order to evaluate the reproducibility of different toxicity tests based on the bioluminescence inhibition of Vibrio fischeri, for the rapid water toxicity assessment.; For the first time, this type of exercise has been organized in Europe, and using different tests based on the same principle. In this exercise, 10 laboratories from 8 countries (Austria, Cyprus, Germany, Greece, Italy, Portugal, Romania, and Spain) took place, and a total number of 360 samples were distributed. During the exercise, six series of six samples were analyzed along 5 months. Every batch of samples was composed by three real samples and three standard solutions. The real samples were: a raw influent and the effluent of a wastewater treatment plant (WWTP)...

Toxicity assays applied to wastewater treatment

Hernando, María Dolores; Fernández Alba, Amadeo R.; Tauler Ferré, Romà; Barceló, Damià
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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9 pages, 6 figures.-- PMID: 18969807 [PubMed].-- Available online Aug 26, 2004.-- Issue title: "Evaluation/Validation of Novel Biosensors in Real Environmental and Food Samples".; The utility and validity of toxicity tests for monitoring of wastewater treatment have been assessed. The evaluated acute toxicity tests have been Vibrio fischeri, Selenastrum capricornotum and Daphnia magna tests. The validation studies indicated that the acute toxicity tests can be considered as high sensitivity analytical tools to detect common environmental concentrations of the pollutants at concentration levels as low as ng l−1. The toxicity tests showed to have discriminatory ability to distinguish between different degrees of toxicity, and the toxic specificity of the compounds on target organisms. Synergistic, additive or antagonistic effects were evaluated indicating the capacity of the toxicity test to assess the combined effects of chemicals in wastewaters. The reproducibility of these tests, calculated as relative standard deviation, is acceptable in the range of 5–22.3%. The application of multivariate date analysis proved that toxicity and chemical measures are complementary analytical tools for monitoring of wastewaters quality. The toxicity tests are useful analytical tools for screening of chemical analysis and as an early warning system to monitor the treatment of WWTPs. The use of single toxicity test or battery of tests is the best approach to evaluate the risk because they are reliable indices of the toxic impact of effluents in the aquatic environment. The toxicity tests were applied in the quality control of different European WWTPs.; This work has been supported by the Spanish Ministry of Science and Technology Project No. PPQ2001-1805-CO3-O3 and European Commission Project P-THREE No. EVK1-CT2002-0116.; Peer reviewed

Role of soil properties in sewage sludge toxicity to soil collembolans

Domene, X.; Alcañiz, Josep M.; Àvila i Castells, Anna; Izquierdo Miguel, Rebeca; Colon Jorda, Joan
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/acceptedVersion Formato: application/pdf
Publicado em //2010 ENG
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Soil properties are one of the most important factors explaining the different toxicity results found in different soils. Although there is knowledge about the role of soil properties on the toxicity of individual chemicals, not much is known about its relevance for sewage sludge amendments. In particular little is known about the effect of soil properties on the toxicity modulation of these complex wastes. In addition, in most studies on sewage sludges the identity of the main substances linked to the toxicity and the influence of soil properties on their bioavailability remains unknown. In this study, the toxicity of a sewage sludge to the soil collembolan Folsomia candida was assessed in nine natural soils from agricultural, grassland and woodland sites, together with the OECD soil. Correlations between the relative toxicity of sludge for collembolans in the different soils and their physical and chemical soil properties were assessed in order to identify the main compounds responsible for the effects observed. Furthermore, the relationships between the toxic effects to collembolans and water-soluble ions released by sludge, pH and electric conductivity were also assessed, together with the modulating effects of soil properties. Sludge toxicity was directly linked to the water extractable ammonium...

Mechanisms of Silver Nanoparticle Toxicity in Laboratory Suspensions and Complex Environmental Media in Caenorhabditis Elegans

Yang, Xinyu
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2014
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The rapidly increasing use of silver nanoparticles (Ag NPs) in consumer products and medical applications has raised ecological and human health concerns. Significant progress has been made in understanding the toxicity of silver nanoparticles (Ag NPs) under carefully controlled laboratory conditions. The goals of this dissertation were to investigate the mechanism of Ag NP toxicity under both laboratory conditions and environmental backgrounds, using Caenorhabditis elegans (C. elegans) as a model system. A key question for addressing these concerns is whether Ag NP toxicity is mechanistically unique to nanoparticulate silver or if it is a result of the release of silver ions. Ag NPs are produced in a large variety of monomer sizes and coatings, and since their physicochemical behavior depends on the media composition, it is important to understand how these variables modulate toxicity.

In order to test the hypothesis of a particle-specific effect, multiple techniques were used, including analytical chemistry, pharmacological rescue, and genetic analysis. Results suggested that dissolution was important for all tested Ag NPs and oxidative stress (a particle-specific effect) was important only for some Ag NPs...