Theses/Dissertations - Environmental Science
Permanent URI for this collectionhttps://hdl.handle.net/2104/4483
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Browsing Theses/Dissertations - Environmental Science by Author "Bruce, Erica Dawn."
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Item Designing quantitative structure activity relationships (QSAR) to predict specific toxic endpoints for polybrominated diphenyl ethers (PBDE) in mammalian cell culture systems.(2011-12-19) Rawat, Swati, 1984-; Bruce, Erica Dawn.; Environmental Science.; Baylor University. Dept. of Environmental Science.Polybrominated diphenyl ethers (PBDEs) are becoming increasingly known as effective flame retardants and have vast industrial application in products like plastics, building materials, and textiles. They are found to be structurally similar to thyroid hormones that are responsible for regulating metabolism in the body. Structural similarity with the hormones poses a threat to human health because once in the system, the PBDEs may change thyroid hormone transport and metabolism. This study is aimed at designing QSAR models for predicting toxic endpoints for PBDEs in mammalian cells. QSAR modeling uses the known chemicals’ activity, which serve as surrogates to study unknown chemicals belonging to the same family. This research is a threefold process including running in-vitro bioassays to collect data on the toxic endpoints, modeling the evaluated endpoints using QSARs and validating the models using compounds of interest from the same family (PBDEs).Item Investigating the efficacy of a novel therapeutic to mitigate traumatic brain injury : contributions of environmental exposures to overall healing.(2015-07-30) Yang, Peijin, 1987-; Bruce, Erica Dawn.Traumatic brain injury (TBI) is a leading cause of disability and premature death among both civilians and military. Morbidity and deaths are mainly caused by several secondary process that exacerbate brain dysfunction in the minutes to days following the primary injury when blood vessels and tissues are torn, stretched, or compressed. In previous studies, proper oxygen supply has been shown to help brain cells to grow and repair, remove the obstruction in blood flow, and alleviate brain edema to prevent secondary injury. OX-66, a novel therapeutic, potentially provides an efficient supply of oxygen to the cells. This therapeutic was investigated in this study to determine its cytotoxicity and potential mechanism of cellular repair in invitro-injured rat brain cells. The effects of exposure to polycyclic aromatic hydrocarbons (PAH) on TBI patients and the corresponding restorative influence of OX-66 were also evaluated.Item The effect of hypoxia on the cytotoxicity of diesel exhaust particles and a novel oxygenating therapeutic in four cell lines.(2020-07-21) Dabi, Amjad, 1990-; Bruce, Erica Dawn.Hypoxia is characterized by oxygen levels in tissue below 2% and is implicated in many diseases and adverse health outcomes including chronic lung disease, neurodegenerative diseases, and delayed wound-healing. Many solutions for tackling hypoxia to alleviate such conditions have been proposed but all carry significant limitations. This study attempts to characterize a novel oxygenating therapeutic known as Ox66™. Another major human health concern is diesel exhaust particles (DEP), a prominent component of air pollution. This study evaluates the toxicity of DEP, Ox66™, and a mixture of both during both hypoxia and normoxia and in 24- and 48-hour exposures using four cell lines. The effect of hypoxia on cytotoxicity carries implications for the health risk assessment of air pollution in patients suffering from hypoxia-related diseases. Additionally, the effect of Ox66™ on the hypoxia induced changes in DEP exposures as observed in their mixture may provide clues about its efficacy.Item Using in vitro to in vivo extrapolation (IVIVE) to develop toxicity metrics for human health risk assessment of polybrominated diphenyl ethers (PBDEs).(2012-11-29) Pree, Krystal.; Bruce, Erica Dawn.; Environmental Science.; Baylor University. Dept. of Environmental Science.Polybrominated diphenyl ethers (PBDEs) are flame retardants found in many industrial components, such as furniture foam, consumer electronics, plastics, and textiles and levels have increased in humans over the past few decades. PBDEs demonstrate adverse neurotoxic effects in mice, are lipophilic, and bioaccumulate in fish. Consequently, PBDE biomagnification may occur, which can be transferred to humans in amounts that may present adverse health effects. This investigation uses in vitro models to calculate bioassay-based reference doses in order to develop a human health risk assessment based on the consumption of PBDE-contaminated fish, using in vitro to in vivo extrapolation (IVIVE). The toxicity effects of ten PBDE congeners were examined and compared among those developed using traditional in vivo mice studies and in vitro models in this study using rat (Clone-9), HEPG2 and zebrafish liver cells to determine the feasibility of using alternative approaches to develop toxicity metrics to evaluate human health risk.