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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

Metabolic enzymes and mixed-function oxygenase (MFO) system in pink snapper (Pagrus auratus): biochemical and histological relationships

Tugiyono, January 2001 (has links)
The environmental health of aquatic ecosystems depends amongst others, on the chemical pollution coming from activities in the catchment's area. In the Swan River Estuary, Western Australia, the chemical pollutants of concern released into the river are petroleum hydrocarbons and sodium pentachlorophenate (NaPCP). Decreased water quality causes a loss of biotic diversity especially amongst fish populations. The health of aquatic ecosystems can be monitored by fish health, especially fish located at higher levels in the food chain. Pink snapper (Pagrus auratus), an endemic Western Australian fish species, was tested for its potential as a bioindicator of aquatic environmental health. This thesis presents data on the responsiveness of pink snapper to the contaminants of concern, using biomarkers such as serum sorbitol dehydrogenase (SDH), mixed function oxygenase (MFO), metabolic enzymes such as citrate synthase (CS), cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH) and the histological alteration such as hepatic cell lesions (hyperplasia and hypertrophy), and glycogen and lipid droplets. The metabolic enzymes CCO and LDH as well as the hepatic MFO induction and histopathology were proven to be the most suitable biomarkers for use for routine monitoring of the Swan River Estuary using pink snapper as a bioindicator. However, CS activity and hepatic cell lesions (hyperplasia and hypertrophy) did not respond to exposure to contamination and are therefore not suited as biomarkers of effects in pink snapper. The first phase of the study aimed at investigating the responsiveness of juvenile pink snapper to an MFO inducer. Polychlorinated biphenyl isomer # 126 was selected as a model MFO inducer for this study. In the initial experiment, MFO activity was measured as a biomarker of exposure, and serum SDH activity was assessed as a biomarker of liver damage. / MFO and SDH activities were of special interest as these biochemical tools have not previously been validated for any Western Australia fish species. Juvenile pink snapper were injected intraperitoneally (i.p.) with 0, 10, 100, 500, 1000 microgram PCB-126 per kilogram. Fish were sacrificed 10 days postinjection, and liver and blood were collected for MFO and SDH analysis, respectively. Doses of 10 and 100 microgram PCB-126 per kilogram caused the highest MFO induction, while doses of 0 and 1000 microgram PCB-126 per kilogram did not result in higher MFO activity relative to carrier-injected (peanut oil) control fish. SDH activities were not significantly different among treatments indicating that hepatocellular damage was not responsible for the reduced MFO activity at the highest dose. Metabolic enzymes in pink snapper exposed by NaPCP were studied in the second phase of the experiment. The aim of this second experiment was to test the responsiveness of pink snapper to contaminants known to cause metabolic perturbations in vertebrates. Juvenile pink snapper were intraperitoneally (i.p.) injected with 0, 5, 10, 20 mg per kilogram. Oxidative enzymes were assessed by measuring CS and CCO activities and glycolytic enzyme was assessed by measuring LDI-1 activity in liver and white muscle tissues. CS activity remained unchanged in both the white muscle and in the liver. CCO activity was significantly enhanced in liver in all treated fish relative to control fish, but not in the white muscle. LDH activity was also higher in liver in all treated fish as compared to control fish, while in white muscle, LDH activity significantly increased at the highest dose injected. / The use of a suite of biochemical markers is useful in determining the effects of xenobiotic exposure of aquatic organisms, because it provides a holistic approach with biomarkers at different levels of biological organization. For the third and final phase of the study the suite of biomarkers selected were MFO, metabolic enzyme (CS, CCO and LDH) activities, and histological alternations in combination with physiological indices. The aim of this last experiment was to investigate if a modified liver metabolic activity would alter the MFO induction potential. To test if altered liver metabolism would influence liver detoxication capacities, juvenile pink snapper were i.p. injected with peanut oil (control), or pentachlorobiphenyl # 126 (PCB 126), with sodium pentachlorophenate (NaPCP), or combination of PCB 126+NaPCP. Relative to controls, ethoxyresorufin-O-deethylase (EROD) activity was induced in the PCB 126 and PCB 126+NaPCP fish, but not in the NaPCP group. In the liver, CCO activity was enhanced by the treatments while CS activity remained unchanged and LDH activity was increased in the NaPCP treatment only. In the white muscle, only the PCB 126+ NaPCP treatment enhanced CCO activity, with all other enzymatic activities remaining unchanged. Low serum sorbitol dehydrogenase (sSDH) activity and histopathology of the liver indicated no significant alteration of cellular structure, albeit the lipid droplet size was increased in the PCB 126 and in the PCB 126+NaPCP treatments. / It is concluded that the hepatic metabolic changes correspond to histopathological observations, but an altered metabolic capacity does not influence the metabolism of xenobiotics by liver enzymes, as measured by EROD activity. These experiments answered the need to identify a suitable fish species for routine monitoring of the aquatic environment in Western Australia. It also identified the most suitable biochemical markers of exposure and effects, and the suitability of the pink snapper as a bioindicator. Finally, the experiments investigated interactions between biomarkers and provided new knowledge useful to scientists using MFO and/or metabolic enzymes in field or laboratory toxicology.
2

Exposition domestique à des polluants chimiques de l’air intérieur : modélisation et évaluation de l’impact sur la santé respiratoire chez le jeune enfant : Bilan au terme d’une année de suivi de la cohorte de nouveau-nés PARIS / Domestic exposure to indoor air chemical pollutants : modeled exposure related to respiratory health effects in infancy : findings from the PARIS (Pollution and Asthma Risk an Infant Study) birth cohort

Roda, Célina 27 September 2012 (has links)
Problématique : La qualité de l’air intérieur est devenue une préoccupation majeure de santé publique, en raison du temps passé à l’intérieur des locaux et de la diversité des contaminants biologiques et des polluants chimiques présents. Objectifs : Il s’agit de renseigner et de modéliser l’exposition domestique à des polluants chimiques retrouvés dans l’air intérieur et d’en étudier le lien avec la morbidité respiratoire au cours de la première année de vie des nouveau-nés de la cohorte PARIS (Pollution and Asthma Risk : an Infant Study). Méthodes : À 1, 3, 6, 9 et 12 mois, des questionnaires sanitaires sont adressés aux parents pour renseigner la survenue des infections des voies respiratoires et des symptômes évocateurs d’asthme (sifflements, toux sèche nocturne, etc.). Des questionnaires environnementaux sont envoyés en parallèle pour documenter le cadre et le mode de vie des enfants. Pour pallier l’imprécision résultant d’une évaluation de l’exposition aux polluants de l’air intérieur par simple questionnaire, des investigations environnementales complémentaires ont été conduites, à 1, 6, 9 et 12 mois, au domicile d’un échantillon aléatoire de 196 nouveau-nés de la cohorte PARIS et dans des crèches parisiennes fréquentées par ces enfants. Les données issues des mesurages domestiques répétés ont été confrontées aux données recueillies par questionnaires afin d’établir des modèles prédictifs s concentrations domestiques annuelles de polluants. Ces modèles ont ensuite été appliqués à l’ensemble des logements fréquentés par les enfants de la cohorte afin de les classer au regard de leur exposition domestique annuelle pour étudier l’impact sanitaire de cette exposition. Résultats : Les modèles prédictifs des concentrations mesurées ont permis d’identifier les déterminants des niveaux de formaldéhyde, de dioxyde d’azote, de toluène et de tétrachloroéthylène : les sources continues et leur caractère récent (panneaux de particules, parquet vitrifié, stratifié, flottant et peinture), les sources discontinues (combustion et proximité au pressing) et les paramètres d’aération et de ventilation conditionnant l’entrée ou la sortie du polluant selon leur origine dominante. Au cours de la première année de vie, près d’un enfant sur deux présente une infection des voies respiratoires basses, 14,8 % une toux sèche nocturne. Concernant l’impact sanitaire de l’exposition aux polluants chimiques, après ajustement sur l’ensemble des facteurs de risque, seule l’exposition domestique au formaldéhyde majore la survenue des infections et plus particulièrement des infections sifflantes. L’exposition au formaldéhyde est aussi associée à la toux sèche nocturne et plus particulièrement chez les enfants sans antécédents parentaux d’allergie. Conclusion : Une exposition domestique aux polluants chimiques de l’air intérieur, tels que le formaldéhyde, peut être associée à la morbidité respiratoire du jeune enfant. Ces résultats viennent appuyer les mesures prises par les pouvoirs publics concernant les émissions des matériaux / There is a growing public health concern about indoor air quality due to the time spent indoors and the presence of numerous biological and chemical pollutants. Aims: To assess indoor chemical pollutant levels, to model domestic exposure and to examine the impact of indoor chemical pollutants on the respiratory health of infants from the PARIS birth cohort, during their first year of life. Methods: Multiple self-administered questionnaires were used to gather information from parents about respiratory infections and asthma-like symptoms (wheezing, nocturnal dry cough. . . ) in their infants at ages 1, 3, 6, 9 and 12 months. Details about home characteristics and family living conditions were also collected by phone interview when the child was 1 month old, and mailed questionnaires captured changes at 3, 6, 9 and 12 months. Pollutant air sampling (aldehyde, volatile organic compound, nitrogendioxide and nicotine) were conducted at 1, 6, 9 and 12 months in the bedrooms of a subset of randomly selected 196infants. Repeated pollutant measurements were joined with interview and questionnaire information to construct annual pollutant exposure models for all infants. Furthermore, an environmental investigation was performed in Parisian child day care centers to document chemical exposure levels. Results: Formaldehyde, toluene, nitrogen dioxide and perchlororethylene level determinants: continuous sources (particleboard, varnished parquet floor, wall coating), discontinuous sources (combustion, dry cleaning facilities) and aeration parameters were identified. At one year, around half of babies experienced at least one lower respiratory infection, and nearly half of those infections included wheezing, 14,8 % of babies suffered from a nocturnal dry cough. After known risk factors were considered, lower respiratory infections were associated with estimated formaldehyde levels, and formaldehyde exposure is also related to nocturnal dry cough, especially in infants without parental history of allergy. Conclusion: This study shows that formaldehyde exposure in early life is associated with respiratory health in infants, promoting public actions regarding emissions from materials
3

Perfluorooctane sulfonate and perfluorooctanoate contamination of riparian wetlands of the Eerste, Diep and Salt Rivers

Mudumbi, John-Baptist Nzukizi January 2012 (has links)
Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2012. / Perfluorinated compounds (PFCs), in particular perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) have been found in aquatic environments throughout the world. Recent studies have reported that owing to their bioaccumulative nature, PFCs may also be present in various water sources, resulting in human and wild-life exposure. Although, these PFCs usually occur at low concentration levels, their presence in the environment has nevertheless been a concern in both developed and developing countries, since water remains an important natural resource for most living species. Water and sediment from rivers are one of the matrices in which PFC contamination is studied, since rivers receive water from various sources. However, limited studies have been conducted in South Africa on PFC contamination of river water and sediments. Although PFCs are sometimes unintentionally released into the environment, the concentration and type of PFCs that contaminate water sources vary among countries and depend on the types of industry releasing them into the environment, suggesting that PFC contamination patterns can be expected to differ from country to country, with PFOA and PFOS being the predominant perfluorinated contaminants. The aim of this study was therefore to determine the concentration of PFOS and PFOA in riparian wetlands of the Western Cape, focusing on the Eerste, Diep and Salt rivers, which are the primary rivers in the largest catchment areas of the Western Cape, South Africa.
4

"Avaliação da atividade clastogênica do resíduo catalítico industrial, por meio do bioensaio de micronúcleos com Tradescantia pallida cv. Purpurea" / Clastogenicity evaluation of industrial catalytic waste using the Tradescantia pallida cv. Purpurea micronucleus biossay (Trad-MCN)

Santos, Iara Terezinha Queiroz Pereira dos 03 September 2004 (has links)
O objetivo deste estudo foi aumentar o banco de dados em relação a resíduos (cake) e efluentes (licor) industriais e o seu nível de clastogenicidade. Este estudo contribuiu para mostrar: a) que o bioensaio com Tradescantia pallida foi sensível para a avaliação da clastogenicidade em mistura complexa de resíduos catalíticos industriais, nunca testados anteriormente. b) a tendência de uma dose resposta para ambos os resíduos catalíticos c)a pasta (cake) apresenta maior clastogenicidade que o licor nas concentrações estudadas. Provavelmente isto se deve a menor concentração de Ti e Al no licor do que no cake. / The aim of this study was to increase data concerning liquid effluent (liquor) and solid waste (cake) and their level of clastogenicity using TradMCN. This study contributed to show a) bioassay Trad-MCN with Tradescantia pallida was sensitive to evaluate the clastogenicity in a complex waste mixture, never tested before b) a tendency of a dose response for both catalytic wastes. c) higher clastogenicity of cake comparing to liquor effluent in concentrations evaluated. Probably this is due to the much lower Ti and Al concentrations in the liquor than in the cake
5

"Avaliação da atividade clastogênica do resíduo catalítico industrial, por meio do bioensaio de micronúcleos com Tradescantia pallida cv. Purpurea" / Clastogenicity evaluation of industrial catalytic waste using the Tradescantia pallida cv. Purpurea micronucleus biossay (Trad-MCN)

Iara Terezinha Queiroz Pereira dos Santos 03 September 2004 (has links)
O objetivo deste estudo foi aumentar o banco de dados em relação a resíduos (cake) e efluentes (licor) industriais e o seu nível de clastogenicidade. Este estudo contribuiu para mostrar: a) que o bioensaio com Tradescantia pallida foi sensível para a avaliação da clastogenicidade em mistura complexa de resíduos catalíticos industriais, nunca testados anteriormente. b) a tendência de uma dose resposta para ambos os resíduos catalíticos c)a pasta (cake) apresenta maior clastogenicidade que o licor nas concentrações estudadas. Provavelmente isto se deve a menor concentração de Ti e Al no licor do que no cake. / The aim of this study was to increase data concerning liquid effluent (liquor) and solid waste (cake) and their level of clastogenicity using TradMCN. This study contributed to show a) bioassay Trad-MCN with Tradescantia pallida was sensitive to evaluate the clastogenicity in a complex waste mixture, never tested before b) a tendency of a dose response for both catalytic wastes. c) higher clastogenicity of cake comparing to liquor effluent in concentrations evaluated. Probably this is due to the much lower Ti and Al concentrations in the liquor than in the cake

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