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Toxicology Commons

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Full-Text Articles in Toxicology

The Role Of Cyp2a5 In Cadmium-Induced Liver Injury, Julia Salamat Dec 2018

The Role Of Cyp2a5 In Cadmium-Induced Liver Injury, Julia Salamat

Electronic Theses and Dissertations

Cadmium is present in food and groundwater. Tobacco smoking and occupational exposure are also major sources for cadmium. Cadmium is primarily accumulated in liver, a major organ metabolizing exogenous chemicals. Chemical metabolism may cause detoxification, but it can also cause bio-activation resulting in liver damage. Cytochrome P450s (CYP) are major liver metabolism enzymes, and cadmium chloride (CdCl2) can induce CYP2A5 in mice. We examined the effect of CYP2A5 on CdCl2-induced liver injury using CYP2A5-knockout (cyp2a5-/-) mice. The cyp2a5-/- mice and their control WT mice were injected CdCl2 intraperitoneally at 5 mg/kg body weight, respectively, to induce liver injury. …


Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich Aug 2018

Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich

Electronic Theses and Dissertations

Arsenic is a metalloid that contaminates drinking water supplies worldwide. Due to concerns for human health, the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) have established a safe level in drinking water of ≤ 10 ppb. Arsenic has been shown to have carcinogenic effects in humans at high and low doses. Chronic exposure may result in dermal conditions such as hyperkeratosis and hyperpigmentation. Recently, arsenic exposure has also been linked to lower IQ values in children. The effect of arsenic on neurogenesis, specifically eye development, has not been widely explored. This study aimed to examine the …


Molecular Mechanisms Underlying Toxicant Effects On Mast Cell Signaling And Mitochondria, Juyoung Katherine Shim Aug 2018

Molecular Mechanisms Underlying Toxicant Effects On Mast Cell Signaling And Mitochondria, Juyoung Katherine Shim

Electronic Theses and Dissertations

Mast cells contribute to numerous physiological processes and diseases including immunological and neurological roles. Mast cells degranulate, releasing potent mediators, following signaling transduction initiated by receptor crosslinking. Previously, we showed that the environmental toxicant arsenic and the antibacterial agent triclosan inhibit mast cell degranulation; thus, we have investigated the mechanisms underlying their inhibitory action. We have discovered that arsenic targets early steps in the mast cell signaling pathway: it inhibits phosphorylation of early tyrosine kinase Syk and of Syk’s direct substrate PI3K. Arsenic’s tyrosine phosphorylation inhibition causes inhibition of calcium influx into the cytosol, a key event necessary for degranulation. …


Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller Aug 2018

Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller

Electronic Theses and Dissertations

The inherent heterogeneity of tumor tissue presents a major challenge to nanoparticle-medicated drug delivery. This heterogeneity spans from the molecular to the cellular (cell types) and to the tissue (vasculature, extra-cellular matrix) scales. Here we employ computational modeling to evaluate therapeutic response as a function of vascular-induced tumor tissue heterogeneity. Using data with three-layered gold nanoparticles loaded with cisplatin, nanotherapy is simulated with different levels of tissue heterogeneity, and the treatment response is measured in terms of tumor regression. The results show that tumor vascular density non-trivially influences the nanoparticle uptake and washout, and the associated tissue response. The drug …


Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner May 2018

Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner

Electronic Theses and Dissertations

Pollutants released by industrialized nations between 1960 and 2004 have been transported northward through atmospheric processes and deposited into glaciated alpine ecosystems. Many of these chemicals retain their original structure and are absorbed into the biota thousands of miles away from where they were originally utilized. With a warming climate increasing the melt of alpine glaciers, these glaciers may be introducing growing amounts of toxins into the watershed. While studies have demonstrated the existence of resident pollutants within glaciated ecosystems, no one has developed a risk assessment to identify sources and quantity of risk posed by these compounds when released …


The Combined Neuropharmacology And Toxicology Of Major 'Bath Salts' Constituents Mdpv, Mephedrone, And Methylone, Serena Allen May 2018

The Combined Neuropharmacology And Toxicology Of Major 'Bath Salts' Constituents Mdpv, Mephedrone, And Methylone, Serena Allen

Electronic Theses and Dissertations

The synthetic cathinones, 3,4- methylenedioxypyrovalerone (MDPV), 4-methylmethcathinone (mephedrone), and 3,4- methylenedioxymethcathinone (methylone), gained worldwide notoriety as the psychoactive components of ‘bath salts;’ a marketing term used to circumvent federal drug laws and permit their legal sale. Previous studies have shown that these drugs share pharmacological characteristics with cocaine and the amphetamines, however, descriptions of their neurotoxic properties are limited. Moreover, while forensic analysis has revealed that the most frequently abused bath salts ‘brands’ contain binary and ternary mixtures of MDPV, mephedrone, and methylone, the majority of preclinical research has focused on explicating the individual effects of these drugs. Therefore, the …


Vinyl Chloride Enhances Diet-Induced Liver Injury Via Metabolic Dyshomeostasis : Critical Role Of Mitochondria., Anna L. Lang May 2018

Vinyl Chloride Enhances Diet-Induced Liver Injury Via Metabolic Dyshomeostasis : Critical Role Of Mitochondria., Anna L. Lang

Electronic Theses and Dissertations

Background. Vinyl chloride (VC) is an environmental toxicant and has been shown to be directly hepatotoxic at high exposures. However, recent studies suggest low-level toxicant exposure can cause subtle changes to the liver. Given the high prevalence of non-alcoholic fatty liver disease (NAFLD) in the United States, it is important to determine the impact of low-level toxicant exposure on the progression of underlying liver injury when combined with other factors. Therefore, the overarching goal of this dissertation was to develop a model of VC co-exposure with high-fat diet (HFD) and to determine the mechanisms by which VC contributes to the …


The Effects Of Polychlorinated Biphenyls Exposure On Non-Alcoholic Fatty Liver Disease : Role Of Aryl Hydrocarbon Receptor., Hongxue Shi May 2018

The Effects Of Polychlorinated Biphenyls Exposure On Non-Alcoholic Fatty Liver Disease : Role Of Aryl Hydrocarbon Receptor., Hongxue Shi

Electronic Theses and Dissertations

Polychlorinated biphenyls (PCBs) are detectable in serum of 100% of adults in US, and has been associated with fatty liver disease in epidemiological studies. PCBs are classified as either dioxin-like (DL) or non-dioxin-like (NDL) PCB based on their ability to activate the aryl hydrocarbon receptor (AhR). We used exposures that reflect human bioaccumulation patterns, which resembles Aroclor 1260 with a low level of the DL-PCB, PCB 126. Our aim was to determine if this exposure will activate the human and mouse AhR and examine if receptor activation influences these steatotic responses due to PCB exposures. DL-PCBs exposure-induced AhR activation in …


A Model To Study The Effects Of Whole Life Chronic Exposure To Arsenic Or Cadmium On The Development Of Adult Metabolic Syndrome : Initial Characterization Of Hepatic Changes., Jamie L. Young May 2018

A Model To Study The Effects Of Whole Life Chronic Exposure To Arsenic Or Cadmium On The Development Of Adult Metabolic Syndrome : Initial Characterization Of Hepatic Changes., Jamie L. Young

Electronic Theses and Dissertations

Metabolic syndrome (MetS) is a group of diseases affecting < 30% of adults. Although obesity is a major risk for the development of MetS, it does not account for all cases, suggesting contribution of other risk factors. We hypothesized that early life exposure to arsenic (As) or cadmium (Cd) may represent such a risk. The purpose of this study was to characterize a model to discern the effects of early life exposures to Cd and As on high fat diet (HFD)-induced MetS. Adult C57BL/6J mice were exposed to control or metals containing drinking water. Pregnant dams and offspring were continuously exposed to the same toxicants as their parents. At weaning, offspring were fed LFD or HFD and sacrificed 10 or 24 weeks later. Metal exposure caused time- and sex-dependent alterations in HFD-induced variables of liver damage. The initial results suggest that these toxicants enhanced obesity-induced liver injury.