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1
Verhagen, Franciscus Johannes Josephus. "Toxicology of the food additives BHA and BHT." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1989. http://arno.unimaas.nl/show.cgi?fid=5479.
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Bradburne, Susan Janet Ann. "Quantitative structure-toxicity studies of compounds in food contact materials." Thesis, Liverpool John Moores University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292314.
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KRUMHAR, KIM CARLETON. "STRUCTURAL AND NUTRITIONAL CHANGES IN IRRADIATED FOOD PROTEINS (ANTIOXIDANTS, QUALITY, PROCESSING EFFECT TOXICOLOGY, RADIATION)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188051.
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A two part study was designed to investigate radiation-induced structural and nutritional changes in food proteins. Model systems composed of 0.1-10% myoglobin, lactalbumin or BSA were used and the effects of propyl gallate, ascorbic acid, air or nitrogen, pH 5, 6 or 7 citrate or phosphate buffer, and addition of glucose and SDS were investigated. We found that 0.02-0.04% propyl gallate (PG), alone or in conjunction with other solutes, inhibited protein aggregation after irradiation to 0.5 and 1.0 megarad and subsequent -20 C storage for 3-6 months. PG alone at 0.04% yielded up to 90% retention of myoglobin after 0.5 megarad and up to 94% retention of lactalbumin after 1.0 megarad as compared to unirradiated controls. BSA appeared more radiation sensitive than other proteins, and use of 0.02% PG yielded retention of only 10% of the original protein after 1.0 megarad. Use of synergists such as glucose or SDS together with PG allowed up to a two-fold increase in protein retention, while use of 0.02% ascorbic acid led to lower retention compared to samples irradiated alone in control buffer. Irradiations at pH 5 and 6 yielded greater protein retention than at pH 7. Isoelectric focusing of myoglobin revealed acidic shifts in protein pI with new bands at pH 4.9-5.2 after irradiation at pH 6 with glucose and PG. A similar acidic shift was seen in focusing lactalbumin, with major new bands forming at pH 3.7-4.0 after irradiation in pH 6 phosphate with 0.04% PG. BSA showed a bipolar pattern of pI shifts after irradiation in pH 6 phosphate. Mice fed irradiated lactalbumin in factorial studies grew slightly faster and ate more than unirradiated controls, while those fed protein irradiated with 0.02% PG showed slightly decreased rates of gain and feed consumption. Amino acid analysis revealed a 35% decrease in lysine, as compared to control, in diets prepared with protein irradiated to 1.0 megarads in 0.05 M phosphate, pH 6 with 0.02% PG. The negative effects of PG on feeding and growth were reduced when protein was irradiated at 22.5% rather than 15% (w/v). Liver to body weight ratios among animals fed protein irradiated with PG were decreased by 18% in contrast to control animals fed identical, though unirradiated, diet. (Abstract shortened with permission of author.)
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Juranovic, Lillian Regina 1962. "Determination of the toxic/mutagenic potential of toxins associated with ciguatera dinoflagellates." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277164.
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Toxic/mutagenic potentials of Gambierdiscus toxicus (GT) and Prorocentrum lima (PL) methanol extracts (CME) were determined using brine shrimp (Artemia salina), mouse, chicken embryo and Salmonella microsomal assays. PL-CME and GT-CME were toxic to shrimp and mice. Isolation and separation were accomplished using ether/water, hexane/methanol partition and butanol extraction. Toxic fractions were purified using column and thin layer chromatography (TLC). GT-CME showed low levels of mutagenic potential. For GT isolated fractions and PL-CME, no mutagenic effects were observed. Both CMEs showed embryotoxicity, with no teratogenic effects. Ether/methanol and water/butanol fractions showed shrimp toxicity. These fractions were purified by treatment with warm/cold acetone. Acetone insoluble precipitates were obtained. Ether soluble acetone filtrate (ESAF) and butanol soluble acetone precipitate (BSAP) showed shrimp and mouse toxicity. GT-BSAP produced temperature depression in mice. Three toxic isolates were obtained from PL-ESAF, four from GT-ESAF and one from both BSAPs columns. TLC preparative plates showed at least 12 toxic isolates for PL-ESAF, 8 for GT-ESAF and 4 for GT-BSAP.
5
Boyce, Antony. "Modulation of the genetic toxicology of the food-derived heterocyclic amines by the phytoalexin resveratrol." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421308.
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Leeves, Sara Ann. "Bioaccumulation of arsenic, cadmium, mercury, lead and selenium in the benthic and pelagic food chain of Lake Baikal." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13438.
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Increased anthropogenic release of potentially toxic trace elements such as arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and selenium (Se) into freshwater ecosystems over the past century has caused much concern. These elements are well known toxicants in aquatic ecosystems and may exert toxic effects even if present at relatively low concentrations in organisms. In this study, bioaccumulation of As, Cd, Hg, Pb and Se in the pelagic and benthic food chain of Lake Baikal have been investigated, with focus on the benthic and pelagic fish species. Concentrations of the selected trace elements have been analyzed in samples of water, plankton, benthic invertebrates and fish by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Concentration differences in the benthic and pelagic food chain of Lake Baikal have been investigated, with focus on benthic and pelagic fish species. In addition, spatial differences in the concentration of these potentially toxic elements between Selenga Shallows (possibly polluted site) and Listvyanka Bay (reference site) were included in the analysis to reveal potential anthropogenic impact on the lake.The comparative study revealed some concentration differences in water and biotic components at the two sampling locations. The concentration of Pb was significantly higher in water from the Selenga Shallows. However, several of the biota samples had highest concentrations of trace elements at Listvyanka Bay. This can be related to higher bioavailability of trace elements at Listvyanka Bay, possibly caused by lower abundance of natural ligands at this location. In both the pelagic and benthic food chain of Lake Baikal, Hg showed indication of biomagnification while As, Cd and Pb seemed to be biodiluted. When comparing fish inhabiting the pelagic and benthic food chain, differences in concentrations of As and Hg were identified. The As concentrations were twice as high in pelagic fish, while the benthic fish had seven times higher Hg content compared to pelagic fish. The observed concentration differences of As and Hg may be related to such as different complexity of the two food chains, different feeding strategies and habitat. Based on the tissue Se:Hg molar ratio there is no risk of Hg induced toxicity in the endemic fish species of Lake Baikal at the present. In general, the present study confirms low concentrations of potentially toxic chemical elements (As, Cd, Hg, Pb and Se) in Lake Baikal in comparison to other freshwater ecosystems.
7
Spencer, Julie Andrea. "Cryopreservation of hepatocytes from rodents and food-producing animals and their use for in vitro toxicology." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313353.
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Lavoie, Raphael A. "Relating trophic structure to mercury distribution in a Gulf of St Lawrence food web: From zooplankton to colonial seabirds using stable nitrogen and carbon isotope analysis." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28093.
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Even at very low concentrations in the environment, mercury (Hg) has the potential to biomagnify in food chains reaching levels of concern in apex predators such as fish-eating seabirds. The aim of this study was to determine the trophic structure and the transfer of total mercury (THg) and methylmercury (MeHg) in a Gulf of St. Lawrence food web using stable nitrogen (delta 15N) and carbon (delta13C) isotope analysis. Since food is the main exposure route to Hg in organisms, I wanted to characterize and compare the diet of top level predator seabirds using traditional and novel techniques. I found that body weight, trophic level and lipid content of organisms were the best predictors of THg and MeHg in this food web. Although the influence of habitat on the overall Hg distribution in the food web was low, I was able to demonstrate an effect within taxonomical groups which indicates that sediments are a source of THg and MeHg in this ecosystem. Several organisms at the base of the food chain were above the MeHg threshold level for the protection of wildlife suggesting a potential threat for upper trophic level predators. Diet composition of seabirds determined using traditional and novel techniques led to similar and complementary results illustrating that these methods can be combined for future studies to monitor prey availability and to predict the exposure of consumers to Hg.
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Tessier, Catherine. "Ecotoxicological impacts of zebra mussels, Dreissena polymorpha, a new food source for lesser scaup, Aythia affinis." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34468.
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Zebra mussels (Dreissena polymorpha) have invaded a great proportion of the waters of the eastern part of North America. This mollusk may be a useful sentinel species for bioaccumulation of heavy metals and organic contaminants in aquatic ecosystems. The zebra mussel's capacity to bioaccumulate cadmium at environmentally relevant exposure and to sequester metals in metal-binding proteins, metallothioneins, was investigated. Elevated (relative to control) concentrations of Cd$ sp{2+}$ were detected in Dreissena exposed to $ ge$2 $ mu$g Cd/liter suggesting that zebra mussels cannot regulate Cd$ sp{2+}$ of trace exposure concentration. More than 85% of the measured Cd$ sp{2+}$ was bound to metallothioneins.Lesser scaup (Aythya affinis) was assessed as a model species for potential impacts of zebra mussels on higher trophic levels. The feasibility of incubating and rearing scaup in semi-natural conditions was evaluated. A series of biomarkers was assessed in 3 groups of scaup fed a contaminant-free diet or diets containing zebra mussels from the St-Lawrence River or Lake Erie.
Lesser scaup proved to be a suitable species to raise in captivity providing daily water misting through out incubation and strict hygiene conditions during brooding. A hatching success of 89% was achieved. Appropriate housing, feeding and bathing conditions yielded low (3%) post-hatching mortality.
Phagocytosis and respiratory burst activities of heterophils of scaup were suppressed after 6 weeks of feeding on zebra mussels, compared to the control group. These two heterophilic functions were negatively correlated with the incidence of pododermatitis (bacterial feet infection), suggesting a suppression of the non specific immunity. Increased liver/body mass ratio and decreased hepatic vitamin A (retinol and retinyl palmitate) concentrations were observed in scaups fed zebra mussels. Lipid accumulation and glycogen overload were found in the livers of scaups fed mussels from the St-Lawrence River and the Lake Erie groups, respectively. These immunological, biochemical and histopathological biomarkers show promise for monitoring "early" injury and may help in the understanding of health impairment of different species of waterfowl exposed to xenobiotics via contaminated food sources.
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Vigren, David. "Migration of Xenoestrogens from Plastic Food Containers during Cooking." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-43957.
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Xenoestrogens are compounds, foreign from the body, that can enter cells and interact with the estrogen receptors (ER) to produce an estrogenic response. Many additives used in plastics are compounds with estrogenic activity. Some of these additives are known to slowly leach from the plastics. When using plastic containers as lunchboxes for reheating or food storage, these additives can leach from the plastics and end up in the food. In this project, food simulates were cooked in six different thermoplastic containers, made of polypropylene, in an oven at 100 °C for 15 minutes. Three of the thermoplastic containers were lunchboxes marketed to be able to withstand cooking in a microwave. The other three were provisional lunchboxes made from various food storing containers originally made for refrigeration purposes. The estrogenic activity in the different samples was measured using an ER-CALUX in vitro assay. The results were measured in 17β-estradiol equivalent (Bio-EEQ) values in pg/ml. The purpose of this project was to investigate whether or not these plastic containers leach xenoestrogens that can be measured with an ER-CALUX assay, and compare the results with the results from other existing toxicological studies, and also to see if there is a difference in Bio-EEQ levels between the plastic containers made for microwave usage and those made for refrigerated purposes. The results from this project indicate that most of these plastic containers do leach estrogenic compounds that can be detected in the ER-CALUX, even the ones made for microwave usage. Fortunately, compared to other toxicological studies, the Bio-EEQ levels in these food samples cooked in plastic containers are low. However the potential adverse effects in prenatally exposed children cannot be ignored as other studies have shown that very low levels of xenoestrogens are enough to potentially cause a disturbance in the reproductive development and fertility.
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Assunção, Ricardo Manuel Abreu de. "Children exposure to multiple mycotoxins through food consumption: a holistic approach for risk assessment." Doctoral thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/21305.
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Food ingestion is considered a major route of human exposure to chemical contaminants, namely
mycotoxins. Considering their toxic and carcinogenic effects, mycotoxins exposure assessment assumes
particular importance, especially when vulnerable populations as children, are involved. Although there
are increasing evidences of mycotoxins co-contamination in food, scarce data are available concerning
children exposure to multiple mycotoxins, their bioaccessibility and the potential toxic effects resulting
from intestinal exposure. Addressing these considerations, this thesis main objectives were: to
characterize Portuguese children (under 3 years old) exposure to multiple mycotoxins through food
consumption; to determine mycotoxins bioaccessibility in foods usually consumed by children; to evaluate
intestinal toxic effects associated to mycotoxins exposure; and, to characterize the risk associated to the
consumption of foods, considering data from exposure assessment, bioaccessibility and intestinal toxicity
assays. The present thesis applied for the first time a holistic approach, gathering results obtained through
different first-line methodologies, comprising probabilistic tools to estimate mycotoxins daily intake and in
vitro assays to determine bioaccessibility and toxic effects. Results revealed a potential health concern for
aflatoxins exposure with regard to the high percentiles of children intake. For the first time, a potential
synergism was described relatively to the combined intestinal toxic effects of patulin and ochratoxin A,
two known enterotoxins. The obtained results reinforce the importance to use a holistic approach to
multiple mycotoxins risk assessment, especially for vulnerable populations as children. Particular
attention should be dedicated to evaluate the consequences of intestinal exposure to mycotoxins, in
particular to their impact on the development of intestinal diseases; RESUMO:
EXPOSIÇÃO DE CRIANÇAS A MÚLTIPLAS MICOTOXINAS ATRAVÉS DO CONSUMO DE ALIMENTOS:
UMA ABORDAGEM HOLÍSTICA À AVALIAÇÃO DE RISCO
A ingestão de alimentos é considerada a principal via de exposição humana a contaminantes químicos,
dos quais se destacam as micotoxinas. Em virtude dos seus efeitos tóxicos e carcinogénicos, é
fundamental avaliar a exposição a estes compostos, particularmente em populações vulneráveis, como
é o caso das crianças. Nos últimos anos, alguns estudos têm dedicado especial atenção à co-contaminação de alimentos por micotoxinas. No entanto, são ainda escassos os dados disponíveis
relativos à exposição das crianças a múltiplas micotoxinas assim como a sua bioacessibilidade e
potenciais efeitos tóxicos a nível intestinal. Neste contexto, a presente Tese teve como principais objetivos:
caracterizar a exposição das crianças portuguesas (idade inferior a 3 anos) a múltiplas micotoxinas
através da alimentação; determinar a bioacessibilidade das micotoxinas nos alimentos habitualmente
consumidos pelas crianças; avaliar os efeitos tóxicos intestinais associados à exposição simultânea a
micotoxinas; e, caracterizar o risco associado ao consumo de alimentos, coligindo resultados da avaliação
da exposição, bioacessibilidade e toxicidade intestinal. A presente Tese desenvolveu pela primeira vez
uma abordagem holística, reunindo resultados obtidos através de diferentes metodologias,
nomeadamente ferramentas probabilísticas para estimar a ingestão diária de micotoxinas e ensaios in
vitro para determinar a bioacessibilidade e efeitos tóxicos. Os principais resultados revelaram, pela
primeira vez, que a exposição a aflatoxinas pode representar um risco potencial para as crianças que
apresentaram os percentis mais elevados de ingestão. Foram também descritos efeitos sinérgicos
inéditos decorrentes da exposição intestinal simultânea a duas enterotoxinas: patulina e ocratoxina A. Os
resultados obtidos reforçam a importância da implementação de uma abordagem holística para a
avaliação de risco de misturas de micotoxinas, em especial quando envolvidas populações vulneráveis
como as crianças. As potenciais consequências da exposição intestinal a micotoxinas deverão ainda ser
ponderadas, principalmente no que respeita às implicações no desenvolvimento de doenças intestinais.
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Creton, Stuart Kevin. "Cellular and molecular toxicology of the food-derived carcinogen 2-amino-1-methyl-6-phenylimidazo (4,5-b) pyridine (PhIP)." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411680.
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Li, Yingxuan. "Contamination evaluation of polychlorinated biphenyls (PCBs) in plants : occurence, distribution and food safety in rice (Oryza sativa L.) and sesame (Sesamum indicum L.)." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1000.
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Pereira, Regiane Guimarães Landi. "Critérios de avaliação de risco de praguicidas em alimentos vegetais como ferramenta de gerenciamento da segurança alimentar no Brasil." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-15012018-160425/.
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A segurança alimentar tem sido um tema cada vez mais importante das metas dos órgãos governamentais, não apenas no sentido de garantir que a população dos países tenha acesso a alimentos, mas que estes alimentos estejam dentro de padrões de qualidade nutricional e os limites de resíduos químicos ou microrganismos não causem prejuízos à saúde da população. A comparação entre as legislações existentes no Codex Alimentarius, nos Estados Unidos e no Reino Unido, sobre a maneira como os limites de segurança alimentar de praguicidas são obtidos, permitirá a obtenção de subsídios que, certamente, contribuirão para a construção de uma proposta para a avaliação deste risco no Brasil. A avaliação do risco da ingestão de resíduos de praguicidas presentes no alimento é feita pressupondo-se que Risco = f(toxicidade, exposição), onde a toxicidade é inerente ao praguicida, sendo determinada em estudos conduzidos em animais de laboratório. Já os dados de exposição são oriundos dos estudos de campo e de consumo dos alimentos. Países como os Estados Unidos e o Reino Unido, preconizam que a avaliação do risco deva ser feita por etapas, partindo do cenário mais restritivo e quando este se mostrar impeditivo, fazer um refinamento dos dados, considerando outros cenários de exposição para posterior tomada de decisão. No presente trabalho foram comparados dois praguicidas de uso autorizado no Brasil, nos Estados Unidos e no Reino Unido e que apresentam tolerância estabelecida pelo Codex Alimentarius. Foram utilizados os modelos de cálculo de cada entidade regulamentadora e obtidos os seguintes resultados: no Brasil o Clorpirifós atinge 41,03% da IDA, para as demais entidades o valor é inferior a 4,5% da IDA. No caso do Tebuconazol, observa-se que no Brasil o produto atinge 35, 17 % da IDA e nas demais instituições o valor é inferior a 8% da IDA. Diante dos resultados obtidos, temos que o critério adotado pelo governo brasileiro encontra-se distante da realidade, e embora o valor obtido no cálculo seja maior do que nas demais instituição, este não significa que a população brasileira está mais protegida do que as demais. Existe a necessidade de implementar o banco de dados brasileiro para que a avaliação do risco seja feita de forma mais adequada, possibilitando a geração de informações que suportem o gerenciamento do risco e viabilize medidas adequadas de mitigação deste risco, quando existente. Embora o Brasil seja um membro signatário do Codex Alimentarius muitos critérios e conceitos desta entidade não foram implementados pelo governo brasileiro.Food safety is an important goal for governmental agencies, not only aiming access to food by populations in all countries, but also assume nutritional quality standards and limits of chemical residues or microorganisms that do not cause damages to the population. The comparison of existing legislations in the Codex Alimentarius, United States and United Kingdom in relation to the procedure on how pesticide limits of food safety are established will allow the attainment of subsidies that, certainly, will contribute for the elaboration of a proposal for risk evaluation in Brazil. Risk evaluation of the ingestion of pesticide residues in food is made estimating that Risk = f(toxicity, exposure), where the toxicity is inherent to the pesticide, and it is determined by animal assays a exposure data are derived from field studies and food consumption. United States and the United Kingdom, consider that risk evaluation must be established by stages, starting from the most restrictive cenario and when it is impeditive, it is necessary a refinement of the data, considering other exposure situations for final decision. ln the present work two pesticides of authorized use in Brazil had been compared, with the United States and the United Kingdom and with the tolerance established for the Codex Alimentarius. The models used for calculation showed that in Brazil, Chlorpyrifos reached 41.03% of the ADI , and the other institutions showed value below of 4,5% of the ADI. In the case of Tebuconazole it is observed that in Brazil the product reaches 35, 17 % of the ADI and in the other institutions the value was lower than 8% of the ADI. The results showed that the criterion adopted by the Brazilian government are unreal, and even if they are higher than the ones found by other institutions, they do not mean that the Brazilian population is more protected than the others. It is necessary to implement Brazilian data base in relation to food consumption so that the risk evaluation can be more reliable and consistent to allow an effective risk management, when needed. Although Brazil is a signatary member of the Codex Alimentarius many criteria and concepts of this entity had not been yet implemented by the government.
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Kosa, Maha Bahjat 1962. "Biotransfer/accumulation of toxins produced by dinoflagellate Prorocentrum concavum to domino damsel (Dascyllus trimaculatus) fish." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277937.
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Toxic dinoflagellate Prorocentrum concavum cells (DC) implicated in ciguatera poisoning were lyophilized and mixed with a standard fish food and fed to Domino damsel fish (Dascyllus trimaculatus). Damsel fish fed 50/50-SC/DC and 100% DC diets exhibited physical and behavioral changes as well as death. Feed refusal was apparent among the fish fed 100% DC diet. Toxicity of the control group could be attributed to previous exposure of the fish to other polyether compounds in its natural habitat or even other chemicals. Fish extracts of both control and treatment groups were toxic when tested on the Stick-enzyme immunoassay for ciguatoxin. Okadaic acid was detected in P. concavum, but no okadaic acid was found in any of the fish tissue extracts. Further studies are needed to determine the transfer of toxin to the fish through diet before any conclusion is made.
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Yeung, Lau-kong, and 楊柳江. "Review of food safety policy in Hong Kong: challenges brought by ciguatera on the safe consumption of live reeffish." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45013664.
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Williams, Lisa R. "A Quantitative Assessment of Minerals of Toxicological Importance in Utah Fast Foods." DigitalCommons@USU, 1989. https://digitalcommons.usu.edu/etd/5373.
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X-ray flourescence (XRF) and atomic absorption spectrophotometry (AAS) measurements for manganese, iron, copper, and zinc were compared for 96 samples of 21 foods from different sources. Correlation coefficients were 0.94 for manganese, 0.99 for iron, 0.93 for copper, and 0.91 for zinc for XRF vs. AAS determinations.
Similiar comparisons were performed on 228 samples of fast foods purchased in Utah retail outlets. Correlation coefficients ranged from 0.91 for copper to 0.97 for iron and zinc. Comparisons of values generated by XRF for manganese, iron, copper, zinc, selenium, arsenic, and aluminum to values certified by the National Bureau of Standards indicated no significant differences by student's t tests.
The simultaneous multielement capabilities of XRF allowed for an extensive screening study for high levels of toxic minerals in the fast foods. Levels of selenium, arsenic, and aluminum in fast foods were determined by XRF. Inductively coupled plasma was used to screen for high cadmium levels since cadmium detection limits by XRF were too high to be of value.
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McCracken, Christie Joy. "Toxicity of Food-Relevant Nanoparticles in Intestinal Epithelial Models." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437688702.
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Sanchez, Nicolas. "Distribution and Variation of the Trace Metal Iron in the Base of the Pelagic Marine Food Web: A Mesocosm Approach : Trace Metal in marine biology." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18371.
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This study was part of the WAFOW project “Can waste emission from fish farms change the structure of marine food webs?” whose objective was to perform mesocosms experiment to simulate the ammonium enriched environment, caused by salmon aquaculture. In order to assess how changes in the stoichiometry of major elements (nitrogen) in the sea affect the distribution of bioactive trace metals, and its effects on the base of the pelagic food web, the distribution and variation in time of the trace metal iron in the water and within the plankton community was studied along a 22 day experiment. It involved 2 types of water (surface and marine systems) each one, with 1 control and 4 NH4+ concentrations. Additional samples collected in a river transect and in depth provided the general Fe distribution in the environment. The iron concentration in the water was determine for three fractions as: Chelex labile (Total: TFeCh and dissolved: DFeCH), DGT labile (FeDGT) and direct (Total: TFe and dissolved: DFe), whereas the particulate concentration iron in the plankton community was determined both per fraction (PFeSF) and total content (PFe>0.2). Total average per treatments showed higher concentrations for both TfeCh and DFeCh in the marine systems compare to the surface. TFeCh showed general increasing trend in time and with increase NH4+ concentration, with a sharp decrease towards the end of the experiment in both systems. DFeCh pattern was inverse to TFeCh, with general decrease over time but lower in magnitude. FeDGT showed an average lower concentration compare to DFeCh with no define trend over time. Final FeDGT concentrations were significantly lower in treatments with artificial NH4+ addition. PFe>0.2 showed an increasing trend in time and with increased NH4+ in both systems. However when normalized to Chlorophyll-a (Chl-a) or particulate organic carbon (POC) the trend inverted, showing that at higher NH4+ influx the iron per Chl-a or POC decreases. PFeSF major changes occurred in the marine system where a estimation of the ratio between the 20-140 µm and the 2-20 µm fractions, indicative of the dominant phytoplankton size class, was significantly higher in 2 of the 3 treatments with artificial NH4+ addition. This point that the microphytoplankton increased significantly with higher NH4+. The variation over time of the concentration of Fe in the water as in the plankton community, indicate that the concentration of NH4+ can have positive or negative relation depending on the iron form. Whether via increasing the PFeCh, or by reducing the uptake by phytoplankton, a modified C:N:P can affect the cycling of iron, which in turn can have negative or positive feedbacks over the major biogeochemical cycles.
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Manteiga, Raquel 1963. "Toxic and mutagenic potentials of herbal teas." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/292011.
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Three commercially available herbal tea preparations (Weightless, Female Toner, and PMS) and one single ingredient herbal preparation, Chaparral (Larrea tridentata), were sequentially extracted with solvents of decreasing polarity (water, methanol and chloroform) and the crude extracts obtained screened for toxic/mutagenic potentials using the brine shrimp (Artemia sp.), mouse acute toxicity, Salmonella/microsomal mutagenicity, and chicken embryo bioassays. The crude aqueous extract from Weightless Tea was very toxic to brine shrimp larvae and had a cathartic action in mice at the highest concentration tested. While Weightless tea crude water extract was not mutagenic to Salmonella typhimurium TA100 at the concentrations tested, three chromatographic isolates obtained from a silica Gel 60 column were mutagenic to the test organism. Two of these isolates were detoxified after inclusion of a microsomal activation system. The teratogenic potentials of these isolates are unknown as the results obtained from the chicken embryo bioassay were not conclusive.
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Chan, Kit Yan. "Dietary exposure, human body loadings, and health risk assessment of persistent organic pollutants at two major electronic waste recycling sites in China." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/943.
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Chawdhury, Valentina. "HEALTH DISPARITIES AMONG SOUTH ASIANS: IS FOOD INSECURITY THE MISSING LINK?" CSUSB ScholarWorks, 2019. https://scholarworks.lib.csusb.edu/etd/900.
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Objective: Food insecurity among South Asians in the US is a public health issue. Food insecure adults face a plethora of adverse outcomes and research shows that individuals with ancestral origins from South Asia have a higher susceptibility rate for cardiovascular disease after migrating to urban environments. As such, the goal of this study was to research possible barriers South Asians face when creating cultural dishes in the US.
Methods: This was a convergent parallel mixed-methods analysis to understand how South Asians feel about food insecurity. Pricing and availability of cultural food items were obtained from South Asian and Western grocery stores. Focus groups were conducted among twelve participants who identified as South Asian immigrants where participants discussed their experiences obtaining cultural food items. After the interviews, the discussions were transcribed, and patterns were identified and analyzed.
Results: The results of the study demonstrate that South Asians find barriers such as availability, price, and quality when shopping for cultural food items. Participants reported cooking cultural foods at a lower frequency than what they would prefer because while many of the food items commonly used in cultural dishes were available at both Western and South Asian grocery stores, South Asian stores were more expensive. Furthermore, participants reported that some culturally specific ingredients were not available at South Asian stores thus further limiting their ability to cook healthy items.
Conclusion: The results of the study highlight the need for more public health initiative to address food insecurity among South Asians in the US.
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Wei, Jin Chao. "Research on novel sample preparation and analytical methods for trace determination of the pesticides in traditional Chinese medicine." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3953269.
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Zhao, Yinge. "Risk assessment of perfluorinated compound (PFC) contamination and their effects on animal reproductive health." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1416.
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Wang, Hongsheng. "Persistent organic pollutants in aquaculture systems in the Pearl River Delta, with focus on their bioaccessibility via fish consumption." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1258.
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Zhu, Wenying. "GLUCOCORTICOID-INDUCED CHONDROCYTE CYTOTOXICITY AT DOSES RECOMMENDED FOR INTRA-ARTICULAR THERAPY IN HORSES." UKnowledge, 2015. http://uknowledge.uky.edu/gluck_etds/23.
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Intra-articular glucocorticoid injections are commonly used to treat synovitis and osteoarthritis in horses. These agents are highly effective at relieving pain, swelling, and other symptoms of joint inflammation. The drugs also have therapeutic benefits by down regulating the expression of cytokines and protease enzymes that participate in the degradation of articular cartilage. However, detrimental effects on chondrocyte function and cell viability that is independent of osteoarthritis pathogenesis have been described and linked to glucocorticoid use. These side effects are both drug- and dose-dependent. This study tested the hypothesis that manufacture recommended dosage levels of methylprednisolone, betamethasone, and triamcinolone that are widely used in equine clinical practice are cytotoxic to articular chondrocytes. Drug-induced chondrocyte cytotoxicity was evaluated in monolayer cultures, cartilage explants, and equine fetlock joints. Total RNA was isolated from control and IL-1β stimulated primary chondrocytes and synoviocytes in culture. Changes in steady state mRNA for targeted gene transcripts related to inflammation and normal cell function were measured using reverse transcription and quantitative PCR. Inducible nitric oxide synthase activity was evaluated using nitrite production. Drug-induced chondrocyte cytotoxicity occurred at drug dosage levels frequently used in equine clinical practice. Both drug- and dose-dependent effects on chondrocyte and synoviocyte gene expression were observed. Maximum anti-inflammatory activities for the glucocorticoids were observed at in vitro concentrations below manufacturer-recommended levels. Results from this study suggest that lower glucocorticoid dose ranges for intra-articular therapy in horses should be validated to maximize the ratio of their therapeutically beneficial anti-inflammatory efficacy against detrimental effects on cell function and viability.
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Pellegrino-Peard, Patricia L. "A review of research and literature linking breast cancer to pesticides." CSUSB ScholarWorks, 1995. https://scholarworks.lib.csusb.edu/etd-project/1216.
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Oliveira, Marcus William Mauricio de. "Avaliação de resíduos de oxitetraciclina em leite de vacas acometidas de dermatite digital papilomatosa tratadas por aplicação tópica e intramuscular." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-11122017-163649/.
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O presente trabalho visa avaliar a presença de resíduos de oxitetraciclina de longa ação em leite de vacas acometidas de dermatite digital papilomatosa, divididas em dois grupos, tratadas por aplicação tópica e intramuscular, utilizando a técnica de Cromatografia Líquida de Alta Eficiência. Desta forma, objetivando determinar a curva de eliminação da oxitetraciclina de longa ação em múltiplas administr ações e o período de carência desse antibiótico no leite, foram colhidas amostras biológicas em diferentes tempos após a administração do fármaco. O método analítico validado apresentou linearidade, limite de quantificação, recuperação, precisão e exatidão adequados, para a quantificação da oxitetraciclina em leite bovino. Os animais do grupo 2, tratados com a aplicação tópica, não apresentaram resíduos no leite. No grupo 1, onde os animais foram tratados com aplicação intramuscular, o aumento na concentração do resíduo variou de acordo com a proximidade da coleta com a administração, e foram tão altos quanto 4854ng/ml, e os limites máximos de resíduos, foram superiores a tempo de carência preconizado pelos laboratórios farmacêuticos.The purpose of this present work is to evaluate the presence of long action oxitetracic1ine residues in milk from DDP afflicted cows, treated with topic and intramuscular administration (8 animals per group). Analysis were performed by High Performance Liquid Chromatography after treatment with trichloracetic acid. Therefore, aiming to determine the long action oxitetracic1ine elimination curve in milk residues, after multiple administrations, and withdraw period, biological samples were collected in different times after antibiotic administrations. The validated analytic method showed suitable linearity, quantification limit, accuracy, precision and recovery, for quantification of oxitetraciclina in milk. The group in which oxytetracycline, was administred dermically showed any residues in milk in all analysed samples. In the first group, where the animals were treated with intramuscular administration, values as high as 4854 ng/ml were detected, and concentration were higher than Maximum Residue Levels after the withdraw period, determined for the pharmaceutical laboratories.
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Leufroy, Axelle. "Spéciation de l'arsenic dans les produits de la pêche par couplage HPLC/ICP-MS. Estimation de sa bioaccessibilité en ligne et applications à d'autres éléments traces métalliques d'intérêt." Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00770330.
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L'arsenic est un élément présent dans tous les compartiments de l'environnement, et les produits de la pêche représentent une source majeure d'exposition à l'arsenic par le biais de l'alimentation. Même s'il n'existe pas à ce jour de législation sur les teneurs en arsenic dans les aliments en France, les agences gouvernementales évaluent généralement les risques liés à la présence d'arsenic dans les produits de la pêche en se basant essentiellement sur la concentration totale de l'élément, sans tenir compte des différentes espèces présentes ni de leur bioaccessibilité. Par conséquent, le développement de méthodes d'analyse de spéciation revêt un intérêt particulier dans le cadre de l'évaluation des risques. La première partie de ce mémoire présente des informations générales sur les propriétés de l'arsenic, son occurrence dans les différents compartiments de l'environnement et sa toxicité, ainsi qu'une étude bibliographique des méthodes analytiques existantes pour étudier la spéciation de l'arsenic dans les matrices alimentaires, en particulier les produits de la pêche (extraction et séparation/détection). Les différentes approches pour l'évaluation de sa bioaccessibilité et de celle d'autres éléments traces métalliques d'intérêt sont également présentées. La deuxième partie de ces travaux porte sur la validation d'une méthode d'analyse de spéciation des principales espèces d'arsenic dans les produits la pêche (As(III), MA,DMA, As(V), AsB, TMAO, AsC) par couplage entre la chromatographie d'échange d'ions (IEC) et la spectrométrie de masse à plasma induit (ICP-MS) après extraction assistée par micro-ondes (MAE). L'évaluation des performances analytiques de la méthode, les contrôles qualités internes et externes mis en place et les différentes applications, en particulier les données d'occurrence des différentes espèces d'arsenic dans les produits de la pêche les plus consommés par la population française sont présentés et discutés. Dans la troisième partie, la bioaccessibilité maximale de l'arsenic et d'autres éléments d'intérêt est estimée à l'aide d'une méthode de lixiviation en ligne (impliquant la mesure en temps réel par ICP-MS de la fraction libérée par les différents fluides digestifs artificiels). La combinaison de ce procédé avec la méthode d'analyse de spéciation validée permet ainsi d'estimer la bioaccessibilité des différentes espèces d'arsenic.
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Küvecses, Jennifer. "Impacts of heavy metals on lake food webs : changes to the littoral benthic invertebrate communities and the consequences for yellow perch (Perca flavescens)." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29449.
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Metal contamination can disrupt the trophic links in food webs by altering the taxonomic composition and size structure of benthic invertebrate communities. Benthic invertebrate samples and perch (Perca flavescens) were collected from six lakes along a gradient of metal pollution in Rouyn-Noranda, Canada. The benthic communities of the contaminated lakes were less diverse and had smaller individuals (0.09 mg d.w. and 0.16 mg d.w. vs. 0.22 mg d.w. in the reference lake). The stomach contents of perch from contaminated lakes were less diverse, showed a greater reliance on chironomids or zooplankton, and cannibalism than perch from less polluted lakes. The mean size of prey in perch from contaminated lakes was smaller than in reference lakes (3.7 mg d.w. and 7.39 mg d.w. vs. 47.7 mg d.w. and 67.1 mg d.w. in reference lakes). (Abstract shortened by UMI.)
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Esteban, Cláudia. "Comparação entre as concentrações de tetraciclina no plasma, líquido sinovial e leite de vacas com doença do casco, submetidas às administrações intravenosa e intravenosa regional e sua implicação na presença de resíduos no leite." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-04052015-180806/.
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O presente trabalho visa desenvolver métodos que permitam determinar as concentrações de tetraciclina, por Cromatografia Líquida de Alta Eficiência, no plasma e líquido sinovial, além de analisar as concentrações correspondentes em leite de gado leiteiro em lactação submetidos aos tratamentos intravenoso e intravenoso regional. Desta forma, objetivando determinar a depuração da tetracic1ina no organismo dos animais tratados, a concentração do fármaco no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequados à quantificação do antibiótico nas matrizes biológicas estudadas. As amostras de leite de animais tratados com o medicamento por via intravenosa regional, não apresentaram resíduos após 120h da administração do fármaco. O mesmo ocorreu plasma e líquido sinovial após 48 h. Através da administração via intravenosa do medicamento foram observados resíduos no leite em todos os tempos avaliados, ao passo que no plasma e líquido sinovial, a presença do princípio ativo não foi detectada após 72 horas pós-tratamento.The purpose of the present work is to develop methods which allow the determination of tetracycline by High Pressure Liquid Chromatography in serum, synovial fluid, as well as analyze the corresponding milk concentrations in milk cows subjected to intravenous and regional intravenous treatment. Therefore, aiming to determine the clearance of tetracycline in the body of the treated animals, the concentration of the active principle in the action site and the residual quantity in milk, biological matrices were collected at different times. The validated analytical methods depicted suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing the quantification of the antibiotic in the studied biological matrices. In relation to the milk samples from animals treated with the drug by regional intravenous via, they did not present residues of tetracycline after 120 h post-administration. The values were also null for both serum and synovial fluid after 48 h. Through regional intravenous drug administration, milk residues were observed in all the evaluated times whereas for serum and synovial fluid, the presence of the active principle was not detected after 72h post-treatment.
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Almeida, Marise Cristina Soares de. "Avaliação dos teores de arsênio total em cação, por meio de técnicas espectrométricas." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-23012018-170851/.
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O arsênio é um importante contaminante estudado em toxicologia, pois pode estar presente em alimentos e no meio ambiente. Seus efeitos nocivos para humanos depende da forma química, onde os arsenicais trivalentes apresentam maior toxicidade e as formas inorgânicas são melhor absorvidas pelo organismo. Seus efeitos tóxicos podem envolver os sistemas respiratórios, gastrointestinal, cardiovascular, nervoso e hematopoiético. O arsênio pode ser encontrado em alguns gêneros alimentícios em concentrações menores que 1 mg/Kg. Em frutos do mar, tais como peixes pode conter teores que vão desde 1 a mais de 100 mg/Kg e em outros alimentos à base de peixe podem chegar à algumas miligramas por quilo, predominantemente na forma orgânica. A quantidade de arsênio ingerido pelo homem está diretamente influenciada pelo consumo de alimentos marinhos incluídos na dieta. Este trabalho tem por objetivo comparar duas técnicas: a colorimétrica, com o método do dietilditiocarbamato de prata e por absorção atômica com gerador de hidratos (HGAAS) e com isso avaliar a presença de arsênio em amostras de cação comercializadas na cidade de São Paulo. O método colorimétrico do dietilditiocarbamato de prata, baseia-se na transformação das diversas formas orgânica ou inorgânica de arsênio presentes nos alimentos, em pentóxido de arsênio e sua redução final à arsina, através do meio ácido e da presença de hidrogênio nascente liberado na reação do ácido com zinco metálico. No segundo método as amostras são mineralizadas e quantificadas no Absorção Atômica com gerador de hidretos(HGAAS).O método do dietilditiocarbamato de prata apresentou limite de detecção e quantificação de 0,05 e 0,1 µg/mL, respectivamente. A linearidade obtida com massas de 5 a 20 µg apresentou um coeficiente de determinação de 0,9970. Por este método foram analisadas 18 amostras de cação com níveis entre 0,17 à 3,79 mg/Kg. Com a técnica por HGAAS foi analisado MRC de ostra e foi obtido recuperação em torno de 94%. Foi encontrado limite de detecção de 0,93 µg/L e limite de quantificação de 1,49 µg/L. Foram analisadas 9 amostras por ambas as técnicas e 89% delas continham teores de arsênio total acima de 1 mg/Kg, que é o limite admitido pela legislação brasileira.Arsenic is an important pollutant studied in toxicology, due to the fact that it can be present in food and in the environment. Its toxicity for humans depends on its chemical structure where trivalent arsenicals show higher toxicity and inorganic forms are better absorbed by the organism. Its toxicant effects can involve the respiratory, gastrointestinal, cardiovascular, nervous and blood systems. The arsenic can be found in some foods in smaller concentrations than 1 mg/Kg. Fish and crustaceous may contain 1 to 100 mg/Kg, in some cases, marine fishes may show amounts of As up to milligrams per killogram, predominantly in the organic form. The amount of arsenic ingested by man is directly influenced by the consumption of marine food included in the diet. This present work compare two techniques: the colorir11etric, with the method of the silver dietylditiocarbamate and the atomic absorption with hydride generator (HGAAS) aiming the evaluation of total arsenic present in samples of fish marketed in the city of São Paulo. The method using silver dietylditiocarbamate, is based on the transformation of all organic or inorganic forms of arsenic present in edible parts of fish, in arsenic pentoxide and its final reduction to arsine. In the second method the samples are mineralized and quantified by atomic absorption with hydride generator. The first method showed limit of detection and quantification of 0,05 and 0,1 µg/mL, respectively. Linearity obtained with masses of 5 to 20 µg showed a coefficient of determination of 0,9970. By this method 18 fish samples ware analyzed showing levels of 0,17 to 3,79 mg/Kg. By HGAAS method oyster certified reference material was analyzed and it was obtained a recovery of 94%, limit of detection of 0,93 µg/L and limit of quantification of 1,49 µg/L. Nine samples were analyzed by both techniques and 89% of them have As content higher than 1 mg/Kg, which is the limit admitted by the Brazilian legislation.
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Pierre, Herma. "Mangiferin as a Biomarker for Mango Anthracnose Resistance." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2247.
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Mangos (Mangifera indica L.) are tropical/subtropical fruits belonging to the plant family Anacardiaceae. Anthracnose is the most deleterious disease of mango both in the field and during postharvest handling. It is most commonly caused by the Colletotrichum gloeosporioides complex. Mangiferin, a xanthanoid compound found in at least twelve plant families worldwide (Luo et al., 2012), is present in large amounts of the leaves and edible mangos. Even though this compound plays a pivotal role in the plant’s defense against biotic and abiotic stressors, no correlations been made between the compound and mango anthracnose resistance.
Mangos were collected, grouped according to their countries of origin, and evaluated for their mangiferin concentrations at four different stages of development. Extracts of interest were then tested against different strains of C. gloeosporioides. The results demonstrated that mangiferin concentrations are significantly different at different stages in fruit development. The antifungal assays were inconclusive.
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Maciel, Edson. "Desenvolvimento e validação de metodologia analítica de multiresíduos para quantificação de resíduos de pesticidas em manga (Mangifera indica)." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-21062005-152523/.
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O objetivo principal deste estudo foi o desenvolvimento e validação de metodologia de análise de multiresíduos para quantificação de resíduos de pesticidas em manga. Foram analisados 32 pesticidas, sendo dos seguintes grupos: 9 Organofosforados, 17 Organoclorados e 6 triazois sendo que neste mesmo método foi analisado novamente o Organofosforado fention. Os organofosforados foram analisados em cromatógrafo a gás (CG) acoplado ao detector fotométrico de chamas e os organoclorados foram analisados em cromatógrafo a gás (CG) acoplado ao detector de captura de elétrons (ECD). Os triazois foram analisados em cromatógrafo a gás acoplado a espectrômetro de massa (CG/MS). A curva de linearidade para todos os padrões analíticos, foi realizada em triplicata e com 6 diferentes concentrações. As fortificações das amostras foram realizadas em dois níveis de concentração, no limite do método e 10 vezes o limite do método, sendo que a concentração do limite de quantificação do método (LOQ) foi realizada com sete repetições (N= 7) e a concentração de 10 vezes o LOQ foi realizada com N= 5, usando-se mangas tratadas no sistema orgânico (livres de pesticidas). Os métodos desenvolvidos e validados neste estudo apresentaram-se: a) Linear na faixa de: 0,1 - 4,0 µg/mL para o triclorfon e malation; 0,05 2,0 µg/mL para os demais organofosforados; 0,05 1,6 µg/mL para os organoclorados; 0,1 1,0 µg/mL para o paclobutrazol; 0,25 - 2,5 µg/mL para o fention e bromuconazol; 0,5 5,0 µg/mL para o tetraconazol e tebuconazol e 1,0 10 µg/mL para o procloraz e difenoconazol respectivamente, uma vez que o coeficiente de determinação foi maior que 0,99 para todos os ativos. b) Específicos, pois o nível de contaminação e/ou interferente na análise do branco dos reagentes e da amostra testemunha, foram inferiores a 30% do limite de quantificação. c) Exato, Preciso e Repetitivo, pois todos os ativos apresentaram recuperação dentro do intervalo de aceitabilidade de 70 a 120%, com coeficiente de variação porcentual (CV%) inferior a 15% em relação à média global de todos os níveis de fortificação. Foram também analisados os mesmos pesticidas em 15 amostras de mangas compradas nos supermercados de Piracicaba, procedentes do Nordeste do Brasil. Em nenhuma das amostras foram encontrados resíduos acima do limite estabelecido por lei ou acima do limite de quantificação deste método, no caso dos pesticidas não autorizados.The principal objective of this study was the development and validation of a multiresidue analytical methodology for the quantification of pesticide residues in mangos. Quantitative analyses were made for 32 pesticides, from the following classes: organophosphorus (9), organochlorine (17) and triazole (6). The results from the method include the first analysis for the organophosphorus pesticide fenthion. The organophosphorus pesticides were analyzed by a gas chromatograph (GC) coupled to a flame photometric detector, while the organochlorine pesticides were analyzed using a gas chromatograph (GC) coupled to an electron capture detector (ECD). The triazoles were analyzed with a gas chromatograph coupled to a mass spectrometer (GC/MS). For each of the analytes, calibration curves were constructed in triplicate using solutions with six different concentrations, prepared from the analytical standards. Recovery experiments were performed at two levels of fortification, the limit of quantification of the method (LOQ) and 10 times this limit. Seven repetitions (N = 7) were performed at the limit of quantification, and five (N = 5) at the 10 times higher level of fortification. Mangos raised by organic farming methods (free from pesticides) were used for the recovery experiments. The methods developed and validated in this study have the following characteristics: a) linear range: 0.1 4.0 µg/mL for trichlorfon and malathion; 0.05 2.0 µg/mL for the other organophosphorus pesticides; 0.05 1.6 µg/mL for the organochloro pesticides; 0.1 1.0 µg/mL for paclobutrazol; 0.25 2.5 µg/mL for fenthion and bromuconazole; 0.5 5.0 µg/mL for tetraconazole and tebuconazole; and 1.0 10.0 µg/mL for prochloraz and difenoconazole, in each case the coefficient of determination was greater than 0.99. b) Specific: thus the level of contamination and/or intereference in analysis from the reagent blank and the control sample amounted to less than 30% of the limit of quantification. c) Exact, Precise and Repeatable, for each of the analytes the recovery was found to be within the acceptable interval of 70 to 120%, and with a coefficient of variation, expressed as a percentage, of less than 15% in relation to the global average of the results obtained at the two levels of fortification. Analyses were made for the same pesticides in 15 samples of mangos bought from supermarkets in Piracicaba, which were raised in the Northeast of Brazil. None of these samples contained residue concentrations above the limit established by law or, in the case of non-authorized pesticides, above the limit of the quantification of the current methodology.
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Taylor, Victoria A. "PHYSIOLOGICAL CHANGES ASSOCIATED WITH PREGNANT OR NONPREGNANT MARES GRAZING PASTURES OF ORCHARDGRASS-BLUEGRASS, KENTUCKY 31 TALL FESCUE INFECTED WITH EPICHLOË COENOPHIALA, OR KYFA9821 TALL FESCUE INFECTED WITH THE NOVEL ENDOPHYTE AR584." UKnowledge, 2017. https://uknowledge.uky.edu/gluck_etds/33.
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Kentucky 31 tall fescue (KY31) infected with the common toxic endophyte strains of Epichloё coenophiala produces toxic alkaloids that improve plant vigor, but cause numerous adverse effects in grazing animals. Researchers developed a variety of KY31 containing an alternative strain of E. coenophiala, termed novel endophyte (NE). Adverse health effects in mares have not been evaluated.
Experiments in this thesis tested the hypothesis that the NE pasture does not cause adverse effects typically associated with KY31. Specific aims were to: 1) compare forage ergovaline concentrations between KY31 vs NE pastures; 2) evaluate palmar artery diameters in mares grazing KY31, NE, or orchardgrass-bluegrass (OGBG) pastures; 3) determine mare serum prolactin, estradiol, and progesterone concentrations associated with ingesting each pasture type over time; and 4) measure foaling outcomes, including percentage of live foals, foal birth weights, and foal growth rates. In 2015, six nonpregnant mares grazed KY31, six pregnant mares grazed NE and six pregnant mares grazed OGBG pastures. In 2016, eighteen mares were used; six mares grazed each pasture type.
Study results showed that ergovaline did not appear to be produced by NE. Novel endophyte pasture did not have negative effects on palmar artery diameter, reproductive hormones, or foaling outcomes.
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Darney, Keyvin. "Towards next generation risk assessment of chemicals : bayesian meta-analysis of human variability in metabolism and transporters and application for the derivation of pathway-related uncertainty factors Aggregate exposure of the adult French population to pyrethroids, in Toxicology and Applied Pharmacology 351, July 2018 Inter-ethnic differences in CYP3A4 metabolism: A Bayesian meta-analysis for the refinement of uncertainty factors in chemical risk assessment, in Computational Toxicology 12, November 2019 Bayesian meta-analysis of inter-phenotypic differences in human serum paraoxonase-1 activity for chemical risk assessment, in Environment International 138, May 2020 Human variability in influx and efflux transporters in relation to uncertainty factors for chemical risk assessment, in Food and Chemical Toxicology 140, June 2020." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0013.
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Dans le monde moderne, les humains sont exposés à une vaste gamme de produits chimiques tout au long de leur vie. L'évaluation des risques des substances chimiques pour l'homme revêt une importance capitale pour la santé publique et permet de calculer des niveaux sûrs d'exposition aiguë et chronique pour des sous-groupes de la population humaine, notamment les nouveau-nés, les enfants, les personnes âgées et les populations d’origine géographique et de polymorphismes génétiques différents. L'application des données cinétiques liées aux voies métaboliques pour tenir compte de la variabilité humaine dans la quantification du danger a le potentiel de réduire l'incertitude et de mieux caractériser la variabilité par rapport à l'utilisation traditionnelle des facteurs d'incertitude par défaut. Cette thèse vise à : 1) Quantifier la variabilité humaine au moyen d'une méta-analyse Bayésienne pour plusieurs voies métaboliques de phase I, phase II et transporteurs en utilisant des marqueurs pharmacocinétiques d'exposition aiguë et chronique ou des données d'activité enzymatique pour les substrats spécifiques disponible. 2) Estimer les distributions de variabilité liées aux voies métaboliques et les facteurs d’incertitudes liés à ces voies pour leur intégration future dans les modèles physiologiques basés sur la cinétique pour l'évaluation des risques des produits chimiques pour l'HommeIn the modern world, humans are exposed to a wide range of chemicals throughout their life. Human risk assessment of chemicals is of considerable public health importance and provides means to derive safe levels of acute and chronic exposure for subgroups of the human population including neonates, children, elderly and populations of different geographical ancestry and genetic polymorphisms. The application of pathway-related kinetic data to address human variability in the quantification of hazard has potential to reduce uncertainty and better characterize variability compared with the use of traditional default uncertainty factors. This thesis aims to 1) quantify human variability by means of Bayesian meta-analysis for a range of phase I, phase II metabolic pathways and transporters using pharmacokinetic markers of acute and chronic exposure or enzyme activity data from available probe substrate, 2) derive pathway-related variability distributions and pathway-related uncertainty factors for their future integration in physiologically based kinetic models for human risk assessment of chemicals
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Distel, Christopher A. "Effects of an Insecticide on Competition in Anurans: Could Pesticide-Induced Competitive Exclusion be a Mechanism for Amphibian Declines?" Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1280363910.
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Monteiro, Davolli Gabriel. "REVERSIBLE DOWNREGULATION OF HYPOTHALAMIC-PITUITARY-GONADAL AXIS IN THE STALLION WITH A THIRD-GENERATION GNRH ANTAGONIST." UKnowledge, 2015. http://uknowledge.uky.edu/gluck_etds/22.
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The objectives of this thesis were: (1) to evaluate the downregulation of the stallion hypothalamic-pituitary-gonadal (HPG) axis by a GnRH antagonist (acyline) based upon endocrine, seminal, testicular and behavioral effects, and (2) to assess recovery after treatment. Stallions were treated for 50 days (n=4; 330µg/kg acyline q 5d) and controls (n=4) received vehicle alone. Stallions were assessed pre-treatment and for 72 days after last treatment. Treatment induced declines (p<0.05) in FSH, LH, testosterone (to castrate levels) and estrone sulfate. Gonadotropins and testosterone returned to control values within nine days and estrone sulfate by 14 days after treatment discontinuation. Acyline-treated stallions failed to respond with FSH, LH and testosterone increase after exogenous GnRH stimulation (25µg gonadorelin, IV) compared to pre-treatment and control stimulation. Total sperm numbers and motility were reduced in acyline-treated stallions, as well as total seminal plasma protein and testicular volume (p<0.05). Time to ejaculation was increased in acyline group (p<0.5). Testicular, sexual behavior and most seminal parameters regained normal levels within 72 days after treatment ceased. Sperm output of acyline-treated stallions was regained within seven months after ending treatment. Acyline reversibly suppressed the stallion HPG axis, thus has potential for treating the androgen-dependent Equine-Arteritis-Virus carrier state and as behavior modulator.
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Da, fonseca Clemens Stéphanie. "Spéciation du mercure dans les produits de la pêche par double dilution isotopique et chromatographie en phase gazeuse couplée à un spectromètre de masse à plasma induit (GC-ICP-MS)." Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00753697.
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Le mercure est un contaminant présent dans l'ensemble des compartiments de l'environnement et l'homme y est directement exposé via l'alimentation. Actuellement, les organismes gouvernementaux évaluent la sécurité des produits alimentaires en se basant essentiellement sur la concentration totale de cet élément. Cependant, la toxicité du mercure dépend, entre autre, de l'espèce absorbée (dont le méthylmercure, sa forme la plus toxique). Par conséquent, l'analyse de spéciation, c'est à dire la détection et quantification des différentes formes chimiques de cet élément, présente un intérêt croissant. Le principal objectif de ce projet a donc été de développer et de valider, sous assurance qualité, une méthode sensible et d'une grande exactitude, basée sur l'utilisation de la dilution isotopique. Elle sera par la suite appliquée comme méthode de référence par l'agence pour l'analyse en spéciation du mercure dans les produits de la pêche afin de permettre une meilleure évaluation des risques encourus par le consommateur. La première partie de ce travail a porté sur l'étude du cycle biogéochimique du mercure et de l'état de l'art des diverses méthodes de préparation de l'échantillon, de séparation et de quantification du Hg dans les matrices biologiques, afin d'émettre des choix analytiques. Ainsi, les principaux composés mercuriels susceptibles d'être retrouvés dans les produits de la pêche (le méthylmercure et le mercure inorganique) ont été déterminés par couplage GC-ICP-MS et une quantification par dilution isotopique. La seconde partie des travaux a été consacrée à l'optimisation de la méthode de préparation des échantillons et de la technique de quantification. Ces travaux sur différents matériaux de référence certifiés ont montré que des modifications de la distribution naturelle de l'échantillon pouvaient survenir dès l'étape d'extraction, préconisant un marquage isotopique avant extraction solide-liquide par digiPREP des espèces mercurielles et dérivation par propylation par le tétrapropylborate de sodium et agitation rotative. Les résultats expérimentaux ont été traités par dilution isotopique simple et multiple. Les teneurs obtenues ont été similaires, pour l'ensemble des matrices analysées, montrant que peu ou pas de transformation inter-espèces surviennent au cours de la procédure analytique. Une quantification par double marquage isotopique et dilution isotopique simple a donc été conservée. L'évaluation des critères analytique a démontré que la méthode est validée pour la spéciation du mercure dans les produits de la pêche, selon les normes françaises AFNOR NF V03-110 de 1998 et de 2010. La dernière partie des travaux a porté sur l'application de la méthode validée à la spéciation du mercure dans des échantillons biologiques réels, ainsi qu'à la participation à plusieurs essais interlaboratoires d'aptitudes organisés par le CSL-FAPAS sur un échantillon de thon en conserve et par l'IRMM sur le matériau IMEP-109 de homard.
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Sherwood, Graham D. "Fish energetics in polluted ecosystems." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38280.
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Conventional wisdom in ecotoxicology predicts reductions in organismal fitness to follow from exposure-related physiological effects. This expectation may be appropriate for controlled laboratory environments, but may not necessarily reflect what is likely to take place in the wild. In an extensive review of the ecotoxicology literature, it was revealed that fish condition factor (an index of energetic fitness) is just as likely to respond favourably to pollutant exposure as it is to respond negatively. The remainder of this thesis examines some of the ecological reasons for this apparent paradox. One possible cause of altered energetic status in wild, pollutant-exposed fish is variable food availability. Addressing this possibility, I showed that consumption rates (estimated using a 137Cesium mass-balance approach) were not related to growth reductions in hormonally-impaired yellow perch ( Perca flavescens) from metal-contaminated lakes. Another possibility is that fish forage less efficiently in metal-polluted lakes as a result of lowered prey choice. In this thesis, I develop an enzymatic and individual-based biomarker for fish activity costs (muscle lactate dehydrogenase, LDH, activity) and show, through the use of this tool that the cost of fish activity is intimately tied to prey type and the ability to make normal ontogenetic diet shifts. Through the application of LDH measurements, as well as through bioenergetic modelling, diet and prey community analyses, a link between decreased prey choice and high perch activity costs leading to zero growth efficiency (energetic bottlenecks) was demonstrated in yellow perch from metal-contaminated lakes. This finding provided one of the first examples in ecotoxicology of a mechanistic link between community and organismal endpoints. The findings of this thesis emphasize the need for ecotoxicology to consider ecology when looking for and interpreting ecologically relevant endpoints. The final chapter of this thesis ex
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Kopp, Benjamin. "Nouvelles approches en toxicologie prédictive pour l'étude de la toxicité des mélanges de contaminants présents dans l'alimentation française." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30208.
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A travers leur alimentation, les consommateurs sont exposés à plusieurs substances chimiques simultanément qui peuvent avoir des effets combinés délétères sur la santé. Six mélanges de contaminants alimentaires auxquels la population française est exposée ont été définis en couplant des données individuelles de consommation et de contamination des aliments. L'objectif de cette thèse était d'étudier in vitro les effets génotoxiques de ces mélanges en utilisant de nouvelles approches. L'étude a montré que deux mélanges étaient génotoxiques et mutagènes, à des concentrations où les composés pris individuellement n'ont aucun effet, suggérant un effet combiné non additif. Nous avons également observé que, pour ces mélange, les effets sont conduits par deux métaux lourds et que leurs effets sont synergiques. Enfin, nous avons achevé cette étude en fournissant des informations détaillées sur les mécanismes d'action des mélanges permettant de mieux comprendre les interactions observéesThrough diet, people are exposed simultaneously to a variety of contaminants that could have combined adverse effects on human health. Six food contaminant mixtures to which the French population is exposed were defined based on individual food consumption data and data on the concentration of chemicals in foodstuff. The purpose of this work was to investigate the genotoxic effects of mixtures in vitro using novel approaches. We demonstrated that two mixtures could be genotoxic and mutagenic, at concentrations for which each individual compound did not induce any DNA damage, suggesting that the combined effect was not additive. We also concluded that, for the two mixtures, the effects were driven by two heavy metals and displayed a great synergy. Finally, we achieved our work by providing detailed information on the mechanisms of action of mixtures to better understand interaction
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Zambrano, Choquehuanca Yanina Inés, and Rivera José Luis Rosales. "Evaluación del efecto genético y toxicológico en expuestos ocupacionales a benceno y tolueno del distrito de Cercado de Lima." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2011. https://hdl.handle.net/20.500.12672/15186.
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Determina en trabajadores de talleres de pintura expuestos a benceno y tolueno, las concentraciones de fenoles totales y ácido hipúrico por método espectrofotométrico, asimismo se evaluó la genotoxicidad mediante el test de micronúcleos y el ensayo cometa. La muestra estuvo conformada por 76 personas, 46 trabajadores de talleres de pintura ―grupo expuesto‖ y 30 personas no expuestas ―grupo control. Se encontraron niveles de fenoles totales (95,2 mg/L) y ácido hipúrico (1,9 g/L) en orina del grupo expuesto, los cuales superan los valores promedios del grupo control 16,7 mg/L y 0,5 g/L respectivamente. Asimismo, supera los valores máximos permitidas según la OMS (75 mg/L y 1,4 g/L). En la prueba genotóxica del test de micronúcleos en células epiteliales de descamación bucal, se encontró 11,7 micronúcleos en el grupo expuesto y 1,7 micronúcleos en el grupo control. En la prueba genotóxica del ensayo cometa en células sanguíneas se encontró daños al ADN tipos grados 1, 2, 3 y 4, los cuales fueron mayores y estadísticamente significativo (p<0,05) en el grupo expuesto en relación al grupo control.Tesis
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Juan, De Dios Miranda Mayra Katherine. "Niveles de arsénico y cadmio en muestras de cebolla (Allium cepa) expendidas en la ciudad de Lima." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/8873.
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Determina los niveles de cadmio y arsénico en muestras de cebolla (Allium cepa) en la ciudad de Lima Metropolitana. Para ello se tomó un total de 30 muestras, 10 muestras en Lima Norte (San Martin de Porres, Los Olivos, Independencia, Comas y Puente Piedra), 10 muestras en Lima Sur (Chorrillos, Villa María del Triunfo, Villa El Salvador, San Juan de Miraflores y Surco) y 10 muestras en Lima Centro (Cercado de Lima, Jesús María, Pueblo Libre, La Victoria y Rímac), donde se tomaron 2 muestras por distrito y al azar, de las cuales se indagó, en cada mercado durante su recolección, el lugar de procedencia de las mismas. Los análisis se realizaron en la Unidad de Servicios de Análisis Químicos (USAQ), empleándose para la cuantificación de estos metales el método analítico de Absorción Atómica – Horno de Grafito. Como resultado se obtuvo que la concentración de Cadmio en las muestras de cebolla presentó una media de 0,06 mg/kg y la de Arsénico una media de 42,0 µg/kg; lo cual indica que la concentración de ambos metales, superan el nivel máximo establecido por la OMS/FAO (Codex Alimentarius; Cd=0,05 mg/kg; As=0-20 µg/kg). Se determinó que en las muestras de cebolla (Allium cepa) procedentes de la zona sur (Arequipa), se acumulan mayor concentración de cadmio y arsénico en comparación con las muestras que proceden de la zona norte (Huaral y Trujillo).Tesis
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Rivas, Altez Walter. "Determinación de arsénico, mercurio y plomo en truchas (Oncorhynchus mykiss), piensos y agua de piscigranjas del distrito de Pachangara, provincia de Oyón, región Lima." Master's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/10095.
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Determina la concentración de metales pesados en las muestras de trucha, agua y pienso que fueron recolectadas de las piscigranjas ubicadas en la jurisdicción del distrito de Pachangara, provincia de Oyón, región Lima, Perú. Realiza una investigación de diseño experimental, observacional, analítico y transversal y utiliza el método cuantitativo. Las muestras fueron analizadas por el método de espectrofotometría absorción atómica. Los resultados obtenidos se compararon con los valores establecidos con el Códex Alimentarius, Comunidad Europea, la Norma Técnica Peruana y SANIPES. Las concentraciones máximas y mínimas de arsénico halladas en muestra de agua de las piscigranjas fueron de 7.480 ppb y 2.100 ppb respectivamente. Las concentraciones máximas y mínimas de arsénico en muestra de trucha fueron de 1.140 ppb y 0.510 ppb. Las concentraciones máximas y mínimas de arsénico en pienso fueron de 18.030 ppb y de 15.010 ppb respectivamente. Las concentraciones máximas y mínimas de mercurio en muestra de agua fueron de 1.510 ppb y 0.401 ppb respectivamente. Las concentraciones máximas y mínimas de mercurio en muestra de trucha fueron de 0.600 ppb y 0.100 ppb respectivamente. Las concentraciones máximas y mínimas de mercurio en pienso fueron de 0.030 ppb y 0.010 ppb respectivamente. Las concentraciones máximas y mínimas de plomo en muestra de agua fueron de 0.180 ppm y 0.040 ppm respectivamente. Las concentraciones máximas y mínimas de plomo en muestra de trucha fueron de 1.140 ppb y 0.510 ppm respectivamente. Las concentraciones máximas y mínimas de plomo en pienso fueron de 2.030 ppb y 1.910 ppm correspondientemente.Tesis
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Pino, Robles Joyce Dione del. "Acción antimicrobiana de los metabolitos secundarios de hojas y flores de Nicotiana paniculata (tabaco cimarrón), extraídos de las Lomas de Lachay." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2008. https://hdl.handle.net/20.500.12672/230.
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El presente trabajo reporta la actividad antimicrobiana y antifúngica de extractos obtenidos de hojas y flores de Nicotiana paniculata L, especie endémica del Perú cuyas muestras fueron colectadas en las Lomas de Lachay, en el Departamento de Lima. Se estudió la actividad antimicrobiana comparando los métodos de Kirby Bauer o disco difusión y el método de excavación placa cultivo encontrando que el método de excavación es más sensible para evaluar actividad antimicrobiana. Las cepas utilizadas fueron Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 6538-P Candida albicans ATCC 10231 y una muestra hospitalaria de Pseudomonas aeruginosa, mostrando actividad antimicrobiana frente a cepas como Pseudomonas aeruginosa y Staphylococcus aureus (16 a 30mm) y ligera inhibición del crecimiento para Escherichia coli y Candida albicans (11 a 15mm).This study report the bacterial and mycotic activity of the extracts from leaves, and flowers from the Nicotiana paniculata L (NPL) samples collected at Lomas de Lachay, Lima region, Perú. The antibacterial activity of the standard strains Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 6538-P, Candida albicans ATCC 10231, and a wild Pseudomona aeruginosa strain was determined by comparison of sensitivity tests using a plate dilution method in which the drugs were provided by impregnated filter papers, and the culture plate hole method recommended by Standard Microbiological Methods (2001). The standard Straits Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 6538-P showed to be susceptibility to the NPL extracts with inhibitory zone from 16 mm to 30 mm; while the Escherichia coli ATCC 10536, and Candida albicans ATCC 10231 displayed intermediate sensitivity (from 11 to 15 mm) to the testing extracts.
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Pereira, Raquel de Cássia. "Ensaio toxicológico in vivo da biomassa de Rubrivivax gelatinosus em ratas /." Araçatuba, 2019. http://hdl.handle.net/11449/182559.
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Orientador: Elisa Helena Giglio PonsanoResumo: A degradação da carga orgânica de efluentes pelo microrganismo fotossintetizante Rubrivivax gelatinosus resulta na produção de uma biomassa de valor nutricional e tecnológico, visto que possui proteínas e carotenoides. Tendo em vista a possiblidade de utilizar tal biomassa como um aditivo alimentício, o objetivo deste estudo foi avaliar a toxicidade aguda in vivo do produto em ratas Wistar. O estudo foi dividido em duas etapas, sendo uma com dosagem única e outra com dosagem repetida, ambas com 15 dias de duração. Na avaliação com dosagem única, 12 ratas da linhagem Wistar com peso acima de 200 g foram divididas aleatoriamente em 4 grupos (3 animais/grupo), para receber as diferentes dietas experimentais: C (controle – óleo de milho), B1 (300 mg de biomassa/kg), B2 (1000 mg de biomassa/kg) e B3 (2000 mg de biomassa/ kg). Na avaliação com dosagem repetida, 15 ratas da linhagem Wistar foram divididas aleatoriamente em 5 grupos (3 animais/grupo) e receberam as seguintes dietas experimentais: RC (controle – óleo de milho), SAT (satélite – 300 mg de biomassa/kg), R1 (50 mg de biomassa/kg), R2 (100 mg de biomassa/kg) e R3 (300 mg de biomassa/kg). As doses da segunda avaliação foram estabelecidas após os resultados do primeiro teste. Em os ambos experimentos, os animais foram avaliados por dados fisiológicos (peso, consumo de ração e água, excretas e temperatura corporal), e comportamentais (screenig hipocrático). Após a eutanásia foram tomados dados sobre o peso relativo de órgãos ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The degradation of the organic load of effluents by the photosynthetic microorganism Rubrivivax gelatinosus results in the production of a biomass of nutritional and technological value, since it has proteins and carotenoids. Considering the possibility of using such biomass as a food additive, the objective of this study was to evaluate the in vivo acute toxicity of the product in Wistar female rats. The study was divided into two stages, one with a single dose and one with a repeated dosage, both with a 15-day duration. In the single - dose evaluation, 12 Wistar female rats weighing more than 200 g were randomly divided into 4 groups (3 animals / group) to receive the different experimental diets: C (control - corn oil), B1 (300 mg of biomass / kg), B2 (1000 mg of biomass / kg) and B3 (2000 mg of biomass / kg). In the evaluation with repeated dosage, 15 Wistar female rats were randomly divided into 5 groups (3 animals / group) and received the following experimental diets: CR (control - corn oil), SAT (satellite - 300 mg biomass / kg) , R1 (50 mg of biomass / kg), R2 (100 mg of biomass / kg) and R3 (300 mg of biomass / kg). The doses of the second evaluation were established after the results of the first test. In both experiments, the animals were evaluated by physiological data (weight, feed and water consumption, excreta and body temperature), and behavioral (hippocratic screening). After euthanasia, data were taken on the relative weight of organs and the histopathology... (Complete abstract click electronic access below)
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Laguna, Gozme Lizabeth Sandy, and Casas Edson Diego Ricaldi. "Determinación de plomo y arsénico en lápices labiales de diferentes marcas que se expenden en Lima Metropolitana." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/6478.
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Determina la concentración de plomo y arsénico en 32 muestras de lápices labiales provenientes de 8 marcas diferentes comercializadas en Lima Metropolitana. La presencia y concentración de estos metales se determinó por el método de Espectrofotometría de Absorción Atómica de Horno de Grafito debido a que es el método de elección según bibliografías actuales. Las muestras fueron adquiridas en cuatro centros comerciales de mayor demanda: Centro Comercial Jockey Plaza, C.C. Mall Santa Anita, C.C. Mega Plaza y C.C. Santa Catalina. Como resultados se obtuvo una concentración media de plomo de 6,60 ppm, con un valor máximo de 71,96 ppm y mínimo de 0 ppm, para el caso de arsénico se obtuvo una concentración media de 3,34 ppm con un valor máximo de 16,59 ppm y mínimo de 0 ppm, del total de muestras el 12,5 % superan los límites establecidos por la FDA para el plomo (≤ 10ppm) y el 40,6 % de muestras superan los límites establecidos por la FDA para el arsénico (≤3 ppm). Se concluye que las concentraciones medias de plomo no superan los límites establecidos por la FDA, sin embargo, la concentración media de arsénico si sobrepasa los límites. Se realizó la comparación de las concentraciones de plomo y arsénico con los límites establecidos por la entidad reguladora obteniendo como resultado que no existen diferencias significativas entre dichos valores. Finalmente se recomienda realizar un seguimiento eficaz en la elaboración, control y regulación de los lápices labiales comercializados en nuestro país, además de establecer una normativa técnica nacional para el adecuado control de metales pesados presentes en este tipo de productos cosméticos.Tesis
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Contreras, Suárez Fernando. "Perfil clínico y epidemiológico de los pacientes intoxicados por plaguicidas organofosforados y carbamatos en el Instituto Nacional de Salud del Niño entre enero de 1998 a diciembre del 2007." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2010. https://hdl.handle.net/20.500.12672/15247.
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Pretende dar a conocer las características clínicas y epidemiológicas de los pacientes pediátricos con intoxicación por organofosforados o carbamatos. Estudio descriptivo, retrospectivo de carácter clínico epidemiológico mediante revisión de historias clínicas de 72 casos atendidos en el servicio de Emergencia del Instituto Nacional de Salud del Niño, con diagnóstico de intoxicación por organofosforados y/o carbamatos entre enero de 1998 y diciembre del 2007. La intoxicación por plaguicidas anticolinesterasas se mantiene como una causa importante de morbilidad en niños. Se reportó un mayor número de pacientes procedentes de áreas urbanas producida principalmente por ingesta accidental de raticidas. En niños, al igual que en adultos existe preponderancia de sintomatología muscarínica (siendo la miosis el signo más frecuente, observándose en el 82% de casos), aunque es común la presencia de signos nicotínicos (siendo las fasciculaciones las más frecuentes con 35% de casos). Aunque la mortalidad en relación a los adultos es baja (5,8% vs. 8-50%), puede producirse complicaciones cardiorrespiratorias con similar frecuencia (19,4% vs. 16-43%).Trabajo académico
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Revilla, Casalino Andrés Salvador. "Cambios inducidos por tolueno y xileno en el estado energético y oxidativo de mitocondrias aisladas." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2008. https://hdl.handle.net/20.500.12672/233.
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Tolueno y xileno son compuestos químicos presentes en varios solventes y otros productos industriales y de laboratorio; su toxicidad para el sistema nervioso central y el hígado ha sido bien documentada. En el presente trabajo, se han estudiado los efectos in vitro de tolueno y de xileno sobre la respiración de mitocondrias aisladas de hígado de rata energizadas con succinato evaluada por medición del consumo de oxígeno, el potencial de membrana usando safranina O como indicador, la liberación de Ca2+ usando Calcium Green 5N, la producción de especies reactivas de oxígeno (EROs) con ácido homovanílico, y los cambios en el nivel de ATP utilizando el sistema luciferina-luciferasa. El hinchamiento mitocondrial, dependiente de Ca2+, sensible a ciclosporina A, un indicador de transición de permeabilidad de la membrana (TPM) mitocondrial, fue monitoreado con la medición de la disminución de la absorbancia aparente a 540 nm. Tolueno y xileno, a concentraciones 0.5-2.5 y 0.25-1 mM, respectivamente, estimularon la respiración de estado 4 en asociación aparente con la disipación del potencial de membrana y la liberación de Ca2+; estos efectos de ambos solventes indican desacoplamiento mitocondrial. A concentraciones mayores (2.5 y 5 mM, respectivamente), tolueno y xileno también inhibieron el estado 3 de respiración. A concentraciones 0.1-1 mM, xileno ocasionó una producción significante de EROs y un hinchamiento mitocondrial parcialmente dependiente de Ca2+ y parcialmente sensible a ciclosporina A. A una concentración 1mM, tolueno o xileno causaron depleciones del ATP mitocondrial hasta niveles del 66.3% y 40.3%, respectivamente; las depleciones fueron sólo ligeramente dependientes de Ca2+. Se concluyó que el desacoplamiento mitocondrial causante de la depleción de ATP puede ser responsable de la toxicidad celular de tolueno y en particular, de xileno, descrita por otros investigadores. En el último caso, parecen también estar involucrados la TPM y la generación de EROs.
Palabras Clave: Tolueno, Xileno, Mitocondria, Desacoplamiento, Especies Reactivas de Oxígeno.--- Toluene and xylene are chemicals present in various solvents and other industrial and laboratory products; their toxicity to the nervous system and to the liver has been well documented. In the present work, we have studied in vitro effects of toluene and xylene on the respiration of succinate-energized isolated rat liver mitochondria, evaluated by measuring oxygen consumption, membrane potential using safranine O as indicator, Ca2+ release using calcium green 5N, reactive oxygen species (ROS) by homovanillic acid, and ATP level changes using the luciferin-luciferase system. Ca2+-dependent, cyclosporine A-sensitive mitochondrial swelling, an indicator of mitochondrial permeability transition (MPT), was followed by measuring the decrease of apparent absorbance at 540 nm. At 0.5-2.5 and 0.25-1 mM concentrations respectively, toluene and xylene stimulated state 4 respiration in apparent association with mitochondrial membrane potential dissipation and Ca2+ release; these effects of both solvents indicate mitochondrial uncoupling. At higher concentrations (2.5 and 5 mM respectively) toluene and xylene also inhibited state 3 respiration. At 0.1-1 mM concentrations, xylene elicited significant ROS generation and partly Ca2+-dependent and partly cyclosporine A-sensitive mitochondrial swelling. At 1 mM concentration, toluene or xylene caused depletions of mitochondrial ATP, amounting to respectively 66.3% and 40.3%; depletions were only slightly dependent on Ca2+. It was concluded that mitochondrial uncoupling via ATP depletion migth be responsible for the earlier described cell toxicity of toluene and in particular, of xylene. In the latter case, mitochondrial generated ROS and MPT also appear to be involved. Key Words: Toluene; Xylene; Mitochondria; Uncoupling; Reactive oxygen species.
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Hualán, Sandoval Luis Felix, and Quispe Jhonnatan Hugo Magallanes. "Determinación de niveles de arsénico y cadmio en bebidas preparadas a base de quinua comercializadas como desayuno en zonas industriales de Santa Anita - Lima Metropolitana." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2019. https://hdl.handle.net/20.500.12672/10918.
Full textAbstract:
Cuantifica la cantidad de arsénico y cadmio en 30 bebidas preparadas a base de quinua, comercializada en el distrito de Santa Anita – Lima Metropolitana. Para obtener la concentración se empleó la técnica de Absorción Atómica con Horno de Grafito. La recolección se realizó en 3 puntos del distrito elegidos al azar: Cruce de la Av. Industrial con Av. Las Torres, cruce de la Av. Marie Curie con Av. Luis Pasteur y el cruce de la Av. Marie Curie con Av. Gutemberg. Los análisis de realizaron en Centro de Información, Control Toxicológico y Apoyo a la Gestión Ambiental - CICOTOX. Se obtuvo un promedio los niveles encontrados, para arsénico se obtuvo 0.048 ppm cuyo punto mayor es de 0.0875 ppm y el menor 0.0109 ppm; para el cadmio se obtuvo 0.031 ppm, un punto mayor de 0.1189 ppm y uno menor de 0.0108 ppm. Se recomienda que las entidades competentes en el país establezcan límites máximos y mínimos de la concentración de estos metales debido a que el Perú no cuenta con un registro con los límites permisibles de contaminantes inorgánicos en alimentos. Se determinó que las bebidas de quinua comercializadas en zonas industriales del distrito de Santa Anita no presentan riesgo de contaminación por metales pesados al ser consumido por la población, pero esto no descarta que se deban seguir realizando estudios en estas zonas.Tesis