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Dissertations / Theses on the topic 'Health Sciences, Toxicology (0383)'

Author: Grafiati

Published: 4 June 2021

Last updated: 17 February 2022

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1

Chow, Jimmy T. "Environmental assessment for bisphenol-a and polycarbonate." Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/368.

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2

Patel, Bhavini. "Lifelong exposure to environmentally relevant doses of Bisphenol A (BPA) alters adult heart structure function." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110541.

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Bisphenol A (BPA), an estrogenic endocrine disruptor, used in the production of polycarbonate plastics and epoxy resins, is found in drinking containers, food packaging and lining of canned goods. BPA can leach from the plastics into food, water, and the environment and is thus the primary cause for the widespread and continuous exposure of BPA to humans. BPA binds to estrogen receptors (ERs) and has also been shown to bind strongly to estrogen related receptor gamma ERRγ. ERs are expressed in human and mouse embryonic stem cells, indicating a fetal cardiac response to sex hormones occurs earl

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3

Chen, Beiyun. "Association between epithelial-cadherin and rat embryo malformations during organogenesis in vitro." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28435.

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This thesis has examined the association between the expression of a cell adhesion molecule, epithelial-cadherin (E-cadherin), and rat embryo malformations induced by three model teratogens and an E-cadherin antisense oligonucleotide during organogenesis in vitro. The embryo malformations induced by phosphoramide mustard (PAM), an active metabolite of an anticancer drug, cyclophosphamide, were not associated with any change in the expression of E-cadherin. The embryo malformations induced by exposure to the phorbol ester, 12-0-tetradecanoyl-phorbol-13-acetate (TPA), were associated with an inc

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4

Qiu, Jianping 1953. "Effects of cyclophosphamide exposure of male rats on progeny outcome and site of action on male germ cell nuclei in the testis and epididymis." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28888.

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Cyclophosphamide is a bifunctional alkylating agent. Administration of low doses of cyclophosphamide to male rats produces severe effects on the outcome of their progeny. The studies in this thesis show that one week treatment with cyclophosphamide can produce about 30% post-implantation loss. This indicates that post-testicular spermatozoa are sensitive to alkylating agents. Previous studies have shown that six weeks treatment caused more than 95% post-implantation loss. The effects of cyclophosphamide treatment on rat spermatozoal nuclei in the testis and epididymis were also addressed in th

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5

Kobiliris, Demetrios. "Influence of embryonic exposure to hexabromocyclododecane (HBCD) on the corticosterone response and "fight or flight" behaviours of captive American kestrels." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95190.

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Hexabromocyclododecane (HBCD) is a brominated flame retardant commonly used in industrial and household products to reduce the spread of fire and the risk of death. Similar to polybrominated diphenyl ethers (PBDEs), HBCD is a ubiquitous and persistent environmental contaminant, highly lipophilic and bioaccumulative, and has been detected throughout various ecosystems and phyla, thus posing potential cause for concern for top consumer species, including birds of prey. Captive adult American kestrels (Falco sparverius) were exposed by diet to HBCD at an estimated daily concentration of 0.8 μg HB

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6

Guest, Ian. "Foetal toxicity of methyl isocyanate metabolites." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41276.

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The foetal toxicity of the methyl isocyanate metabolites trimethylamine (TMA) and S-(N-methylcarbamoyl)glutathione (SMG) was studied in mice. Administration of TMA but not SMG during pregnancy decreased foetal weight and selectively inhibited the postnatal growth of male offspring. Both TMA and SMG were teratogenic to mouse embryos in culture. TMA caused a dorsal-rostral split in the head and SMG produced distortion and separation of somites; both agents decreased the growth of embryos. The inhibition of embryonic growth by TMA could not be antagonized by antioxidants or growth factors. The em

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7

Charoensri, Nicha. "Investigation into genetically programmed responses to cadmium and mercury in HeLa cells by differential display and two-dimensional gel electrophoresis." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84491.

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Cadmium and mercury are among the most toxic metals and can be a serious threat to human health. A clear understanding how cells respond, especially in terms of genetically controlled responses to these two metals, is required in order to develop appropriate prevention and treatment procedures that can protect humans from toxic exposure to these metals. Therefore, this study is aimed at elucidating the genetically programmed response to cadmium and mercury exposure in HeLa cells. Two different approaches were employed for this study. Differential expression patterns of mRNAs were studie

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8

Diaz, Heredia Zuanel. "Trolox enhances anti-leukemic effects of arsenic trioxide: the role of oxidative stress." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40699.

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Arsenic trioxide (As2O3) has considerable efficacy in the treatment of acute promyelocytic leukemia (APL), inducing partial differentiation and promoting apoptosis of malignant promyelocytes. Although initial studies focused on the role of the characteristic APL fusion protein, PML-RARα, in mediating the response to As2O3, recent investigations indicate that its cytotoxic activities are mediated by mechanisms independent of this fusion protein. As2O3 affects numerous intracellular targets mainly through the accumulation of free radicals and consequent induction of oxidative stress and causes a

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9

Saint-Phar, Shawna. "Development and characterization of a mouse model to determine the impact of low dietary folate on spermatogenesis, fertility and histone methylation." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32416.

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Folate is a critical determinant in male reproductive health. During spermatogenesis, there are massive alterations to the epigenome associated with tightly regulated gene transcription and chromatin reorganization including a tightly regulated pattern of histone H3 methylation. In vitro experiments were conducted to determine whether folate depletion could alter global histone H3 methylation at lysine 4 and 9 in cultured spermatogonia-like GC-1 cells. Folate depleted media did not alter global levels of

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10

Kelly, Alexander. "Immunotoxic effects of orally administered sodium tungstate in wild-type and pre-leukemic mouse models." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114605.

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Due to its various desirable properties, tungsten is extensively used in a variety of industrial, military, and residential applications. Despite this wide-spread use, little is known about the toxicological profile and possible health effects of tungsten exposure. High environmental tungsten levels were identified near the site of three childhood pre-B acute lymphoblastic leukemia (preB-ALL) clusters within the United States, however, a causal link between tungsten and leukemogenesis has not been established. The major site of tungsten deposition is bone, the site of B cell development. Thus,

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11

Ma, Yiqian. "Understanding the effects of exposure to an environmentally relevant mixture of brominated flame retardant congeners on the function and development of the male gonad." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117009.

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Brominated flame retardants (BFRs) are a group of industrially important chemicals that are incorporated into a wide variety of consumer products in order to increase their flame ignition resistance. These BFRs are readily released into the immediate environment through a multitude of routes, whereupon an appreciable level can be detected in household dust. The ingestion of contaminated dust is the major source of exposure for humans. Rising body burdens of BFRs over the last decades have led to major concern because of the persistence of BFR in the environment, their bioaccumlative and lipoph

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12

Mbongwe, Bontle. "Fate and persistence of DDT and its metabolites in the Okavango Delta, Botswana." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ67838.pdf.

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13

Shaver, Caryl Smith 1959. "An in vitro model of arsine induced hemolysis and its application to possible treatments." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277980.

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Arsine gas is a potent hemolytic agent. Early work suggested glutathione depletion preceded, and oxygen required for hemolysis to occur. This study developed an in vitro model of arsine hemolysis, using the solubility of arsine gas in aqueous solutions. A total of 75% of the arsine was taken up into the cells within 5 minutes. Hemolysis occurred after 1-2 hours and reached 40-50%. Glutathione depletion occurred, but only after hemolysis reached its maximum. Increasing intracellular glutathione did not prevent hemolysis. The use of an intracellular chelator, monomethyldimercaptosuccinic acid di

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14

Seeto, Kei Fong 1961. "The determination of protein-acetaldehyde adducts in alcoholism." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/278044.

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Acetaldehyde, the first metabolite of ethanol, has been shown to bind to proteins to form protein-acetaldehyde adducts in vivo and in vitro. The effects of acetaldehyde have been implicated in diseases associated with alcoholism. In the present study, we have extended the observations by studying three different protein-acetaldehyde adducts in vitro, and hair keratin-acetaldehyde adduct in alcohol-fed mice in vivo. Our studies reported here suggest that our enzyme-linked immunosorbent assay (ELISA) is able to detect the stable protein-acetaldehyde adducts. In our preliminary application of the

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15

Gustafson, Richard Allan 1958. "Effect of reduced glutathione on the metabolism of chloroaldehydes by rat liver aldehyde dehydrogenase." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278192.

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The identification of chlorinated organic compounds in drinking supplies has resulted in an interest in the metabolism and toxicity of chlorinated aldehydes. Another possible factor in the metabolism of chloroaldehydes is the endogenaous tripeptide glutathione. The formation of glutathioneconjugates with chloroaldehydes may increase or decrease their rate of reaction with the aldehyde dehydrogenase enzyme. This study found that the rat liver aldehyde dehydrogenase isozymes lost activity with time regardless of storage conditions. In vitro assays of enzyme activity confirmed substrate specifici

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16

Cannady, Ellen. "The role of ovarian metabolism in 4-vinylcyclohexene-induced ovotoxicity in B6C3F(1) mice." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280131.

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4-Vinylcyclohexene (VCH), an industrial chemical, causes destruction of small pre-antral follicles (F1) in mice. Previous studies suggested that VCH is hepatically bioactivated to its ovotoxic metabolite, vinylcyclohexene diepoxide (VCD), by the cytochrome P450 enzymes, likely Cyp 2E1, Cyp 2A, and Cyp 2B. Additionally, microsomal epoxide hydrolase (mEH) likely participates in detoxifying the epoxide metabolites. The role of ovarian metabolism (bioactivation/detoxification) of VCH and its metabolites is not known. The hypothesis of this dissertation research was that ovarian metabolism contribu

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17

Petrick, Jay Scott. "Arsenic: Metabolism, cytotoxicity and toxicogenetic alterations in the developing lung." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280443.

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Environmental arsenic exposure is associated with human cancers of the skin, lung, kidney, and bladder. Mechanisms of arsenic toxicity and carcinogenicity, however, remain poorly studied and merit further investigation. The present studies address the effects of arsenic metabolism on toxicity, under the hypothesis that arsenic metabolism results in both detoxication and bioactivation. Inorganic arsenic and methylated metabolites were tested for toxicity in cultured cells, demonstrating that both detoxication and bioactivation occurs with metabolism, dependent upon methylation and valence state

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18

Richards, Victoria Elizabeth. "The role of acetylation in the hepatotoxicity of hydrazine." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280532.

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Isoniazid (INH) is an antimicrobial used around the world in the treatment and chemoprophylaxis of tuberculosis. Hepatotoxicity is a well-recognized adverse effect of INH therapy. Metabolites of INH, namely hydrazine (HD) and acetylhydrazine (AcHD), are believed to be responsible for this hepatotoxicity. Studies were initiated to test the hypothesis that HD and not AcHD administration results in alterations in hepatic lipid homeostasis. In adult male C57B1/6J mice doses up to 300 mg AcHD/kg, p.o. did not produce liver damage. In contrast, exposure to HD resulted in time- and dose-dependent dec

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19

Ziegler, Thomas Lynn 1961. "Absorption and dispositional kinetics of 3,3',4,4'-tetrachloroazoxybenzene and 3,3',4,4'-tetrachloroazobenzene in the male Fischer-344 rat." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282485.

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3,3',4,4'-tetrachloroazoxybenzene (TCAOB), and 3,3',4,4'-tetrachloroazobenzene (TCAOB), which are structurally similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are formed as byproducts during the synthesis of industrial products. They exhibit Ah receptor binding characteristics and activities similar to those defined for TCDD in vitro at equal moral doses. However, they do not express toxicities in vivo at equal molar doses. The reduced in vivo toxicity can possibly be attributed to differences in the absorption and dispositional kinetics of TCAOB and TCAB as compared to TCDD. Thus, in t

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20

Barber, David Stewart 1970. "Correlation of pulmonary arsenic metabolism and toxicity." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282551.

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In lung preparations, As(V) was reduced to As(III) [first order rate constant of 0.0104/min]; As(III) was oxidized to As(V) [first order rate constant of 0.005/min], methylated to MMA [K(m) = 5.383μM, V(max) = 0.00031 μmol/liter/min/mg], and complexed with GSH; MMA was converted to DMA [K(m) = 63.4 μM, V(max) = 0.0000384 μmol/liter/min/mg]; and arsine was oxidized to As(III) and As(V) and methylated. Toxicity of As(III), As(V), MMA, DMA, and arsine was assessed by measuring effects on cell and slice viability hsp32 induction, and production of DNA single strand breaks. Because all species of a

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21

Robledo, Raymond F. 1968. "Pulmonary response to inhaled jet-propulsion fuel 8 aerosol in mice." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288888.

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Studies were initiated to characterize the acute and sub-chronic pulmonary responses to inhaled Jet-Propulsion Fuel 8 (JP-8) aerosol. At 24 to 30 hours following JP-8 exposure, physiological, biochemical, cellular, and morphological techniques were used to assay for lung injury. In addition, C57BL/6 and B6.A.D.(Ahyd mice were utilized in the acute study to determine if responsiveness to aryl hydrocarbon hydroxylase (AHH) induction modulates toxicity. JP-8 contains aromatic compounds that are known substrates for AHH. Acute lung injury was evident by increased respiratory permeability that was

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22

Kirkpatrick, Donald Scott. "The effects of arsenic on the ubiquitin dependent proteolytic pathway." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289893.

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Arsenic is a potent toxicant and known human carcinogen. Arsenite [As (III)], a major inorganic form of arsenic, can stimulate oxidative stress, decrease DNA repair, alter gene expression, modulate stress signaling, and damage proteins in numerous model systems. This dissertation focuses on the effects of low-level arsenite on the ubiquitin-proteasome pathway. Ubiquitin is a small protein that acts as a post-translational modification of other proteins within the cell. In most cases, modification of a protein by ubiquitin acts as a signal for its degradation by the proteasome. Studies performe

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23

Meltzer, Deborah. "Endocrine disruption in the female following «in utero» exposure to the plasticizer di(2-ethylhexyl) phthalate." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123210.

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Di-2-ethylhexyl phthalate (DEHP) is an endocrine disruptor used as a plasticizer in industryas an additive to polyvinyl chloride commodities which include consumer and medical products.Developmental delay induced by exposure to chemicals such as DEHP has been a cause forconcern. In our work, we use a model in which pregnant dams are gavaged with DEHP fromgestational day 14 until birth. We have previously provided evidence that demonstrates theadverse effects of DEHP on the male endocrine system following in utero exposure; however,knowledge of analogous effects of DEHP in the female is lagging

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24

Borman, Sherri Lynn Mobley, and Sherri Lynn Mobley Borman. "Ovarian toxicity of 4-vinylcyclohexene diepoxide and polycyclic aromatic hydrocarbons in mice and rats." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/284020.

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Polycyclic aromatic hydrocarbons (PAHs) are environmental ovotoxicants commonly released in cigarette smoke and vehicle exhaust. PAHs have been shown to target small ovarian follicles (25-100 μm) after a single high dose. Once irreplaceable primordial follicles are depleted in the ovary, ovarian failure results. The occupational chemical, 4-vinylcyclohexene diepoxide (VCD), induces pre-mature ovarian failure in mice and rats. A direct comparison between the ovotoxicity caused by VCD and that of PAHs was made by calculating an initial ovotoxic index (OI = ED₅₀ x 15d) in ovarian follicles of mic

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WANG, BIN. "Enhanced cadmium-induced testicular necrosis and renal proximal tubular damage caused by gene-dose increase in a Slc39a8-transgenic mouse line." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1172086886.

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26

Spear, Philip A. "The action of a dioxin-like compound upon avian thyroid and vitamin A homeostasis." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5144.

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27

Jeffery, Richard William Paul. "Ethoxyresorufin-O-deethylase (EROD) inducing potency of polycyclic aromatic hydrocarbons (PAHs) in avian hepatocyte cultures: Investigations of the ability of an in vitro bioassay to predict the toxic potency of PAHs." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9164.

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Eighteen polycyclic aromatic hydrocarbons (PAHs) and 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) were examined for their potencies to induce ethoxyresorufin-O-deethylase (EROD) activity in primary cultures of White Leghorn chicken (Gallus domesticus), Pekin duck (Anas platyrhynchos), and Greater Scaup (Aythya marila) embryo hepatocytes. Of the 18 PAHs, only eight induced EROD activity. In chicken hepatocytes the rank order of potency of the eight EROD inducing PAHs was BkF ≥ DahA > Ind > BaA ≥ BghiP ≥ Chr ≥ BaP > BNT. A log-log plot of the ECthr plotted against the LD50 (LD50 data fr

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28

Rahayu, Ucu. "The influence of dissolved organic carbon (DOC) and calcium on the toxicity of copper and nickel to the freshwater alga Selenastrum capricornutum and the zooplankter Daphnia magna." Thesis, University of Ottawa (Canada), 2000. http://hdl.handle.net/10393/9241.

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The toxicity of copper and nickel was measured in algal cultures of Selenastrum capricornutum and zooplankton cultures of Daphnia magna to determine if dissolved organic carbon (DOC) and/or calcium concentrations can influence toxicity of these two metals. Water samples were collected from the Raisin River (high DOC and high calcium), the St. Lawrence River (low DOC and high calcium), the Ottawa River (medium DOC and calcium) as well as two lakes in Nova Scotia. The concentration sufficient to kill half the population of Daphnia magna after 48h of exposure (LC50), and the inhibition of cell g

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29

Katynski, Andrea L. "The effects of PCB 126 on embryotoxicity and beta-adrenoceptors in chicken (Gallus domesticus) embryos." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9411.

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Halogenated aromatic hydrocarbons such as polychlorinated biphenyls (PCBs) comprise some of the most toxic and persistent environmental pollutants associated with various developmental and reproductive effects in mammals, birds and fish. Oxidative stress can modify beta-adrenoceptor (beta-AR) function. This thesis examines the effects PCBs on beta-AR function in an avian model. Injection of 1.6 mug PCB 126/kg egg into the air cell prior to incubation increased the % mortality and the incidence of abnormalities, including liver lesions and subcutaneous edema, in day 19 chicken (Gallus domesticu

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30

Cano, Tim. "The use of selected physiological parameters as indicators of polychlorinated biphenyl exposure of rainbow trout, Oncorhynchus mykiss." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/9739.

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Hatchery reared rainbow trout (Oncorhynchus mykiss) were caged at two locations in the St. Lawrence river near Cornwall, Ontario. One cage was anchored in an area of high polychlorinated biphenyl (PCB) contamination, within an iron enclosure near the General Motors Foundry at Massena, N.Y. during a dredging operation designed to remove PCB contaminated sediments from the river. A second control cage was placed in the Snye channel, known to have low PCB concentrations. Hatchery fish were sampled to provide a time 0 control, and fish from each site were collected following 21 and 41 day exposure

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31

Hosseini, Shirazi Seyed Farshad. "Toxicity of cisplatin and its metabolites on ovarian cancer cells." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/9818.

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Cisplatin (CP) is one of our most useful antineoplastic drugs. When CP is dissolved in human plasma, different metabolites are formed. We examined the interactions of CP and its metabolites, namely aquated CP (AP), monomethionine CP (MP), bismethionine CP (BP) and CP dissolved in plasma ultrafiltrate (UP) on the OV 2008 human ovarian cancer cell line. By clonogenic assays, cell survivals (%) with AP, CP, MP, BP and UP were 3.28 $\pm$ 0.73, 9.84 $\pm$ 0.99, 15.93 $\pm$ 1.11, 76.83 $\pm$ 2.13 and 13.11 $\pm$ 0.74, respectively. AP was the most cytotoxic species, and BP was the least cytotoxic sp

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Otto, Diana M. E. "Polychlorinated biphenyl (PCB) alterations of antioxidant defenses and xenobiotic metabolism in teleost fish: Role of tissue glutathione metabolism in xenobiotic detoxication pathways." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10074.

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Polychlorinated biphenyls (PCBs) are ubiquitously distributed in the aquatic and terrestrial environments, even though their production was stopped more than 20 years ago. The biochemical effects of PCBs are primarily initiated by the induction of drug metabolizing enzymes, especially cytochromes P450. In the first instance, these enzymes detoxify xenobiotics such as PCB congeners to facilitate their excretion from the animal. However, these processes are also known to generate more toxic metabolites, including the production of reactive oxygen species (ROS) which impact on cellular antioxidan

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Kirby, Christopher E. "A spatial correlation analysis of broad scale use of agricultural pesticides and infant health outcomes in the United States." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27466.

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Introduction. Birth defects and low birth weight/preterm delivery are the leading causes of a infant mortality in the United States. However, their etiologies remain mostly unknown. There is evidence suggestive of a link between exposure to pesticides and reduced infant health. We sought to answer the question of whether spatial variation in the incidence of infant mortality in the general population is correlated with variation in agricultural pesticide use. Methods. We examined the variation during 1996--2001 among 48 U.S. states of rates of infant mortality due to birth defects, and rates o

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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 f

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Fontaine, Susan Marie. "Molecular basis for the species-dependent bioactivation of vinylcyclohexene: Role of hepatic cytochrome P450 induction." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/279785.

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4-Vinylcyclohexene (VCH) is an intermediate in the production of rubber and styrene. Following repeated exposure, VCH depletes the small pre-antral follicles of B6C3F1 mice. Interestingly, the female rat is resistant to VCH-induced ovotoxicity, which can be partially attributed to a reduced ability in forming the toxic metabolites (VCH-1,2-epoxide, VCH-7-8-epoxide, and ultimately, 4-vinyl-1-cyclohexene diepoxide [VCD]), as compared to mice. Current studies have focused on species dependent bioactivation of VCH, stereochemical considerations in VCH bioactivation, and the role of cytochrome P450

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Derbyshire, Zachary E. "Characterization of the activation and regulation of the serine/threonine kinase, MEKK4." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280601.

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MEKK4 is a recently identified serine/threonine kinase. Upon initiation of this study, MEKK4 had been shown to phosphorylate MKK6, an upstream kinase of the stress activated p38 MAP kinase, although no agonist or directly upstream activating kinase had been reported. To identify proteins that interact with MEKK4, a recombinant form of the protein was used as bait to bind interacting proteins from mammalian cell extracts. Using this method the calcium binding protein, annexin II, was identified as an interacting partner with MEKK4. The Far-Western immunoblot was another approach used to examine

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McVean, Maralee 1967. "Photoprotective actions of vitamin E in mouse skin: Prevention of UVB-induced DNA photodamage." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282563.

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Ultraviolet exposure causes epidermal damage including induction of cyclobutane pyrimidine dimers in DNA. Accumulation of these lesions has been associated with mutagenesis and probably contributes to development of nonmelanoma skin cancer. Topically applied α-tocopherol previously has been shown to prevent UVB induced damage and skin tumor induction in mice. Thus, α-tocopherol, which absorbs strongly in the UVB, may act as a sunscreen to prevent photodamage. This dissertation explored possible mechanisms of photoprotection exerted by α-tocopherol. The UVB dose penetrating the epidermis was me

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Badger, Andrew Ashley 1970. "Alterations in chemically-induced liver injury by immunomodulators." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282642.

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Studies presented in this dissertation determined biochemical mechanisms underlying the modulation of chemical-induced liver injury by retinol and GdC₃ The first objective was to determine the role of inflammatory cells in the retinol potentiation of CCl₄-induced liver injury. Plasma alanine aminotranferase activities and histological analysis of liver sections both illustrated significant potentiation of CCl₄ hepatotoxicity by a single dose of retinol. The mechanism for this potentiation involves priming of Kupffer cells (KC) (i.e. by enhancing their response to toxic stimuli) as established

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Sukbuntherng, Juthamas 1961. "Disposition kinetics of cocaine in rats." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/288778.

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Cocaine is a psychomotor stimulant which is widely abused. To understand the behavior of cocaine, the disposition kinetics of the compound were characterized using the rat as an animal model. A sensitive HPLC assay was developed to quantitate cocaine and metabolites (cocaethylene, norcocaine, benzoylecgonine, and benzoyl-norecgonine) in plasma and urine samples. Since ecgonine methyl ester has insufficient UV absorptivity, the quantitation of this compound in blood and urine was performed by a GC/NPD method. The effects of dose and route of administration on the disposition kinetics of cocaine

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Younis, Husam S. "The molecular and cellular mechanisms of 1,2-dichlorobenzene induced liver injury in Fischer-344 and Sprague-Dawley rats." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290190.

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1,2-Dichlorobenzene (1,2-DCB), an industrial solvent, is a potent hepatotoxicant in Fischer-344 (F-344) rats. Bioactivation of 1,2-DCB by cytochrome P450 enzymes in the liver and subsequent activation of Kupffer cells (KC), the resident liver macrophages, are required for the development and progression of liver damage. The mechanisms by which KC cells become activated in chemical induced liver injury are unknown. The studies described in this dissertation utilized 1,2-DCB as a model hepatotoxicant to test the hypothesis that KC activation following 1,2-DCB induced liver injury is triggered by

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Chambers, Andrea. "The application of categorical regression to model the exposure-response relationship of copper excess and deficiency." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28428.

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There is a need to define an exposure-response curve for both copper excess and deficiency to assist in defining the acceptable range of oral intake. A copper exposure-response database has been developed where response data has been assigned to ordinal severity scores. A generalized linear model was used to estimate the probability of response associated with dose, duration and severity. The exposure-response model is defined to account for differences in animal species, route of exposure and age. The exposure-response curves for copper excess and copper deficiency have defined an optimal int

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Bourland, James Alain 1958. "The influence of ethanol on drug metabolism and disposition via carboxylesterase-mediated transesterification." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/289533.

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Carboxylesterase enzymes hydrolyze a wide variety of ester-containing xenobiotics to yield carboxylic acids. It has now been determined that these enzymes catalyze the ethanolic transesterification of ester-containing compounds. Perhaps the most widely publicized and significant transesterification reaction is the conversion of cocaine (COC) to cocaethylene (CE) in the presence of ethanol. The formed CE possesses pharmacological activity, nearly identical to COC, a longer half-life and is more toxic than COC. We hypothesized that the transesterification of COC to CE is not unique and other com

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Naught, Laura Eisinger. "Arsenic speciation of swine urine for possible use in human exposure assessments." Thesis, University of Missouri - Columbia, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3577952.

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<p> Millions of people are exposed to arsenic in the United States and worldwide. Commonly found arsenic species in human urine are AsIII (arsenite), AsV (arsenate), MMA (monomethyl arsenic acid), DMA (dimethylarsinic acid) and AB (arsenobetaine). Evidence has shown that these species vary in toxicity, and since each of these metabolites can be detected through analysis, they have the potential to be used as biomarkers for human exposure. For human exposure assessments in areas that have naturally occurring arsenic contaminated sources, or those who live or work near contaminated environmental

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Blevins, Lori A. "Ethylene glycol rapid methods of detection." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/18943.

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Master of Veterinary Bioscience<br>Department of Diagnostic Medicine/Pathobiology<br>Deon Van Der Merwe<br>Every year thousands of domestic animals are poisoned by ethylene glycol. Exposure is normally orally, but may be dermal, and poisonings are usually accidental and not malicious. Antifreeze, overwhelmingly the source of the ethylene glycol poisoning, is responsible for over 99% of reported cases. Storage, handling and proper disposal of ethylene glycol is extremely important in limiting access to this deadly product. Ethylene glycol exposures were involved in 1737 calls made to the Ameri

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Afzaal, Nadeem Mohammed. "Gene Expression of Anti-Oxidant Genes (GCL, GPx AND GSTpi) in Zebrafish Exposed to Chemicals That Alter Thyroid Hormone." Thesis, Southern Illinois University at Edwardsville, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1545317.

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<p> Gene expression of the biotransformation enzymes, glutathione S-transferase (GST) glutathione peroxidase (GPx) and glutathione synthesizing enzyme glutamyl-cysteine-ligase (GCL), was investigated in zebrafish (Dani orerio) exposed to arsenate, perchlorate, a mixture of these two chemicals, and thyroxine (T4). The exposure persisted for 30 days for perchlorate, 7 days for arsenate and 7 days for thryroxin. To test the mixture toxicity of arsenate and perchlorate, arsenate was added for 7 days in addition to 30 days exposure to perchlorate. Arsenate is known to induce oxidative stress, and G

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Yeager, Ronnie Lee. "Red light therapy an innovative approach to attenuating dioxin-induced embryo toxicity /." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3264315.

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Thesis (Ph.D.)--Indiana University, Dept. of Environmental Science, 2007.<br>Source: Dissertation Abstracts International, Volume: 68-05, Section: B, page: 2924. Adviser: Diane S. Henshel. "Title from dissertation home page (viewed Jan. 24, 2008)."

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Winski, Shannon Lee 1967. "Interactions of pentavalent and trivalent arsenic with intracellular thiols." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/278054.

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Trivalent arsenic (As(III)) exposure is linked to cancer, but exposure includes pentavalent arsenic (As(V)). These forms interconvert in biological systems, and the mechanism is not understood. Arsenic has a high affinity for sulfhydryls, and the interaction of As(III) and As(V) with biological sulfhydryls and cellular uptake was investigated in this study. Incubation of rat blood at 1 mM arsenic showed As(V) uptake, membrane and protein binding to be time dependant. These processes were almost immediate with As(III) incubation. Incubation at 25 mM As(V) resulted in 40% thiol depletion with no

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Dittmar, Tami Beth. "Identification and determination of arsenic and phosphorus species in environmental and biological samples." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282719.

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The surface of indium phosphide single crystals exposed to synthetic lung fluid (Gamble solution) has been investigated. An oxygen depth profile, obtained by employing the 3.035 MeV resonance in the elastic scattering of alpha particles from 16O, detected oxygen at maximum concentrations of 24% in a layer approximately 1000 A thick. O:In and O:P ratios were found to increase with prolonged exposure time as determined by XPS, although binding energies and peak fwhm's remained relatively constant. The surface concentration of indium was found to be decreased in this 1000 A layer. Indium was dete

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Lim, Jinhwan. "Effects of low-level light therapy on 2,3,7,8-tetrachlorodibenzo-p-dioxin and diabetes-induced oxidative damage in chicken and rat kidney." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3358932.

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Thesis (Ph.D.)--Indiana University, School of Public and Environmental Affairs, 2009.<br>Title from PDF t.p. (viewed on Feb. 10, 2010). Source: Dissertation Abstracts International, Volume: 70-05, Section: B, page: 2888. Adviser: Diane S. Henshel.

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Pirela, Leon Sandra V. "Linking the Exposure to Engineered Nanoparticles Released From Nano-Enabled Products to Toxicology: a Case Study of Laser Printers." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:16121161.

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A research gap in the fields of exposure assessment and toxicology that remains unaddressed is the assimilation of experimental conditions to those of the real world human exposure. Currently, there is a lack of understanding of the properties of particles released by nano-enabled products (NEPs). Thus, we designed a multi-tiered methodology to physico-chemically, morphologically and toxicologically characterize engineered nanomaterials (ENMs) released from NEPs (i.e., toner powder). It is well established that printers emit nanoparticles during their operation; however, the physico-chemical a

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