Pharmacology, Toxicology and Environmental Health Commons^™

Inhibition Of Rad18 By Arsenic, Lindsay B. Volk

Biomedical Sciences ETDs

Arsenite exposure leads to the retention of UV-induced DNA damage, thus burdening translesion synthesis (TLS). Rad18 is an essential factor in initiating TLS through PCNA monoubiquitination and is implicated in homologous recombination. It contains two functionally and structurally distinct zinc fingers that are potential targets for arsenite binding. Results from this study reveal arsenite binding to both zinc fingers of Rad18 and a corresponding loss of domain function. Importantly, arsenite inhibited Rad18 RING-dependent PCNA monoubiquitination and polymerase eta recruitment to DNA damage. Further analysis demonstrated multiple effects of arsenite, including the reduction in the nuclear localization and UV-induced chromatin recruitment …

Hepatocyte-Hepatic Stellate Cell Axis In Potentiation Of Alcohol And Hiv-Induced Liver Injury, Moses O. New-Aaron

Theses & Dissertations

Human Immunodeficiency Virus (HIV) remains a global threat, with approximately 38.4 million active infections and 33 million HIV-related deaths since the first case. While many may be tempted to think of HIV as a relic of the past, emerging data suggests otherwise. By the end of 2021, approximately 1.5 million HIV incidences and 650 000 mortalities were reported globally. The etiologies of HIV-related mortality are numerous. Liver disease is one of the leading etiologies of HIV-related mortality, especially in recent times of antiretroviral therapy (ART)-induced longevity among people living with HIV (PLWH). While co-infections with hepatotropic viruses notoriously contribute to …

Effects Of Microcystin-Lr On Channel Catfish (Ictalurus Punctatus) Susceptibility To Microbial Pathogens (Aeromonas Hydrophila And Edwardsiella Piscicida), Alison Marchant

Theses and Dissertations

Microcystin-LR is a hepatotoxin produced by cyanobacteria. Aeromonas hydrophila and Edwardsiella piscicida infections are leading causes of losses in market-sized channel catfish (Ictalurus punctatus). These older fish should have natural immunity in place and a predisposing factor is likely a prerequisite for these disease outbreaks. While microcystin-LR rarely causes mortality in warm-water aquaculture, we believe it may be a predisposing factor that leads to bacterial disease outbreaks during the summer months due to its ability to damage the liver. Our study investigated microcystin-LR’s effects on channel catfish susceptibility to these pathogens. We found that a sublethal dose of microcystin-LR induced …

Quantifying The Toxicological Effects Of The Organic Uv Filters Avobenzone And Homosalate On Acropora Cervicornis, Samantha F. Buckley

All HCAS Student Capstones, Theses, and Dissertations

Reports of the environmental effects of organic UV filters such as oxybenzone have led to the marketing of “reef-safe” sunscreen ingredients, including avobenzone and homosalate. Avobenzone provides broad-spectrum UV protection which blocks higher wavelength UV rays, the leading cause of aging and skin cancer. However, as polycyclic aromatic hydrocarbons (PAHs), organic UV filters have similar structures to crude oil and estrogens, some of which have been labeled endocrine disrupters. Common in personal care products, UV filters enter marine ecosystems via wastewater effluent and swimmers. Significant stress and mortality have been observed in juvenile and some adult scleractinian corals after exposure …

Insights On The Behavior Of Nano-Copper In The Agroecosystem: Mycorrhizal Associations With Spearmint (Mentha Spicata), Suzanne Annette Apodaca

Open Access Theses & Dissertations

Nanotechnology offers significant potential benefits to our society, including the agriculture sector. With the advancement of nano-enabled agrochemicals towards sustainable and efficient agricultural practices, it is essential to address environmental issues associated with the use of nanoscale materials. The same properties that give promise to applications of nanotechnology in modern agriculture could have unintended consequences on ecosystem dynamics. A point of concern for risk management is the impact of engineered nanomaterials (ENMs) to beneficial microbial communities, which support a variety of ecosystem services.

Use of copper (Cu) products in agriculture are based on their abundance, role as a micronutrient, and …

Developmental Effects Of Chronic Low-Level Arsenic Exposure In Mouse Embryonic Stem Cells And In Human Induced Pluripotent Stem Cells, M. Chiara Perego

All Dissertations

Arsenic is an environmental contaminant commonly found in food and drinking water. Exposure to arsenic during embryonic development has been linked to reduced muscle growth, disrupted muscle development and locomotor activity, impaired neurodevelopment, reduced IQ, impaired memory and learning deficits. While the mechanisms responsible for developmental changes following in utero exposure to arsenic are not well known, one possibility is that arsenic might disrupt proper cellular differentiation. Therefore, we aimed to investigate the mechanisms by which arsenic exposure could alter stem cell differentiation into neurons.

First, we continuously exposed P19 mouse embryonic stem (ES) cells to 0.1 μM (7.5 ppb) …

Effects Of Titanium Dioxide Nanoparticle Injections On Tissue Function And Morphology In Goldfish (Carassius Auratus), Bryan Joel Patterson

Graduate Theses

Fish gills are sensitive to a variety of environmental factors because they regulate the exchange of oxygen and ions between the fish and the external environment. This study examined the effects of polyacrylic acid (PAA) coated titanium dioxide nanoparticle injections (TiO₂ NPs) on goldfish (Carassius auratus) over 14 days. Following the experimental period, we examined gill histological samples and looked for signs of an inflammatory response through blood glucose levels and relevant gene expression. TiO₂ injected fish developed a more robust ILCM (interlamellar cell mass) compared to the non-injected controls, which remained elevated over 14 days post injection. …

Investigation Of Human N-Acetyltransferases (Nat1 And Nat2) Genetic Polymorphisms In Susceptibility To Aromatic Amine And Alkylaniline Genotoxicity., Mariam Habil

Electronic Theses and Dissertations

Arylamine N-acetyltransferases, NAT1 and NAT2, catalyze the detoxification and/or activation of carcinogens. Single nucleotide polymorphisms or SNPs result in different human NAT1 and NAT2 genotypes. We hypothesize that different NATs alleles will impact levels of N-acetylation, HPRT mutations, DNA damage and oxidative stress induced by carcinogens. NER-deficient Chinese hamster ovary (CHO) cells transfected with human CYP1A2 and NAT1*4, NAT1*14B, NAT2*4, NAT2*5B or NAT2*7B have been used to investigate N-acetylation of benzidine, β-naphthylamine (BNA), and 4, 4’-methylene bis (2-chloroaniline) (MOCA) as aromatic amines and 3,4-dimethylaniline (3,4-DMA) as one of alkylanilines and their associated toxicity. Our …

The Impact Of Pharmacogenetics On Oral Fluid Steady State Drug Testing Results, Aliya D. Lewis

Student Theses

Pharmacogenetics refers to the relationship between phenotypic variation in metabolism and response to certain drugs. The interface of pharmacogenetics and forensic toxicology is not well explored. A major component of the opioid metabolic pathway has to do with a family of cytochromes called cytochrome P450 (CYP450). CYP450 refers to a general family of enzymes capable of catalyzing the oxidative biotransformation of lipophilic substances, CYPs are further categorized into families and sub-families (Roller, 2015; Zanger & Schwab, 2013). The gene CYP2D6 belongs to the CYP2 family which is responsible for the biotransformation of xenobiotics. This study looked at the effect of …

The Effect Of Volatile Organic Compounds On Endothelial Function And Atherogenesis., Samantha Mcfall

Electronic Theses and Dissertations

Volatile organic compounds (VOCs) are a group of pervasive air pollutants that are released into the atmosphere from both anthropogenic and environmental sources. Recent epidemiological studies suggest that exposure to various VOCs is associated with an increased risk of cardiovascular disease. However, the relationship between VOCs and cardiovascular disease is not well-studied. Using animal models and three select VOCs, benzene, xylene, and trichloroethylene, we studied the effects of VOCs on endothelial injury and benzene-induced atherogenesis. We found that exposure to benzene and xylene increased circulating endothelial microparticles, depleted progenitor cells, and increased platelet activation. Following the exposure to the representative …

Esterase Mediated Insecticide Resistance In The Southern House Mosquito, Culex Quinquefasciatus, Vivek Pokhrel

LSU Doctoral Dissertations

Much is known about the development of insecticide resistance associated with targeted application against insect populations. However, off-target selection by applications of insecticides in agricultural and residential sites also impacts development of insecticide resistance and is understudied. Similarly, the impact of selecting one life stage of mosquitoes on the insecticide susceptibility of different life stages is largely unknown. The first part of this study shows that susceptibility to chlorantraniliprole, which is applied in rice and sugarcane fields in LA, decreased (5.7 to12-fold) in populations of Culex quinquefasciatus collected from near these fields compared to a reference field strain. In addition, …

Comparison Of The Humoral Immune Response Following Both Bacterial Challenge And Rnai Of Major Factors On Proliferation Of Bartonella Quintana In The Human Louse, Jake Zina

Masters Theses

Human body lice, Pediculus humanus humanus, and head lice, Pediculus humanus capitis, have been hematophagous ectoparasites of humans for thousands of years. Despite being ecotypes, only body lice are known to transmit bacterial diseases to humans, and it appears that lower humoral and cellular immune responses allow body lice to possess a higher vector competence. We previously observed that the transcription level of the defensin 1 gene was up-regulated only in head lice following oral challenge of Bartonella quintana, a causative agent of trench fever, and also that body lice excreted more viable B. quintana in their …

Developmental Exposures To Pfas Mixtures Impair Elongation Of The Exocrine Pancreas In Zebrafish (Danio Rerio), Emily M. Formato

Masters Theses

Poly- and perfluoroalkyl substances (PFAS) are a class of bioaccumulative toxicants used in numerous industrial and commercial products. Perfluorooctanesulfonic acid (PFOS) alters pancreatic organogenesis during development, and perfluorohexanesulfonic acid (PFHxS) has been suggested as a replacement for PFOS due to its shorter carbon chain, but they are often found together in surfactants, such as legacy aqueous film-forming foam. This study investigates how developmental exposures to a PFAS mixture (PFHxS + PFOS) impact the developing exocrine pancreas. Zebrafish embryos (Tg(ptf1a:GFP)) were exposed to 0.01% DMSO, or 8, 16, 32 μM PFHxS alone, 16 μM PFOS alone, and 8, 16, and 32 …

Metal Accumulation In Soils, Invertebrates, And Whiptail Lizards In The Northern Chihuahuan Desert, Allyson Benson-Pedraza

Open Access Theses & Dissertations

Smelting activities by the American Smelting and Refining Company (ASARCO) lead to the substantial release of metal pollution into the El Paso, Texas, and border cities region. To-date few studies have examined metal accumulation within vertebrate taxa in these areas. As reptiles are currently experiencing population declines globally for a variety of reasons including pollution, lizards were chosen to be evaluated for trace element (As, Cu, Cr, Cd, Pb, and Zn) concentrations. These metals were measured within soils, invertebrate prey items, and the livers of three species of whiptail lizards (Aspidoscelis) from the un-remediated University of Texas at El Paso …

Roles Of Oxidative Stress And Dna Methylation In Cigarette Smoking-Induced Accelerated Acute Myeloid Leukemia Progression, Mary Figueroa

Dissertations & Theses (Open Access)

Acute myeloid leukemia (AML) is a commonly diagnosed cancer in smokers. When current or former smokers have AML, they have worse survival compared to never smoking patients. This has been observed clinically for decades, but then it is unknown how smoking leads to worsened AML survival. Smoking causes oxidative stress and altered DNA methylation that persists for decades in peripheral blood mononuclear cells, but these changes from smoking have not been evaluated in the context of AML. We hypothesize that smoking-induced molecular changes, including altered DNA methylation associated with poor AML prognosis, promote AML. We developed a novel model to …

Lc-Ms/Ms Method For The Detection And Quantification Of Pharmaceuticals And Drugs Of Abuse In New York City Waterways, Natalie M. Fernandez

Student Theses

The use of licit and illicit drugs has been increasing significantly over the past few years within the United States. Due to this increase, these drugs are emerging as contaminants in surface and ground water. The presence of pharmacologically active compounds in this environment can be extremely harmful to aquatic life as they are continuously exposed to these substances. The goal of this study was two-fold: 1) Develop and validate an analytical method for 28 different drugs including cocaine, amphetamines, opioids, cannabis, and prescription medicines, in river water; 2) Identify and quantify drugs found in New York City waterways over …

Elisa Validation Method For The Detection Of Ketamine In Hair, Daria A. Centonza

Student Theses

An ELISA method was developed and validated to detect ketamine in human hair samples. Ketamine is an anesthetic drug that causes memory loss, dissociative sensations, and hallucinations. Due to these adverse effects, ketamine is a common drug used in drug facilitated sexual assaults (DFSAs). It is very important to be able to detect the substances used in DFSAs over a longer period of time due to the delayed reporting of these crimes. Victims, often out of fear and from the sedative/memory loss effects of the drugs, tend to report these crimes when it is too late to use urine and …

A Detailed Parameter Study Into The Dermal Absorption Of Chemical Warfare Agents And The Effects Of Pharmacokinetics, Koko Lear

Theses

Chemical warfare agents (CWAs) are substances of varying toxicity profiles. These chemicals exhibit complex dynamics and pose a serious health risk when released into the environment. A mathematical model based on Fick’s second law of diffusion was developed to comprehend how these compounds were absorbed into the skin. The analysis applied to both small and large doses and, successfully, predicted experimental results. This work also includes the effects of CWA physicochemical properties on evaporation and dermal absorption through the stratum corneum. A sensitivity analysis was conducted to assess the impacts of small variations in the initial dose, environmental conditions, and …

Chiral Analysis Of Methamphetamine In Hair Samples, Kristen Payes

Student Theses

Methamphetamine (MAMP) is a highly addictive illicit drug typically abused for its nervous system stimulating effects. Conversely, methamphetamine has therapeutic use treating attention deficit hyperactivity disorder, controlling appetite and assisting with weight loss, and is available as the pure l-isomer in over-the-counter (OTC) nasal inhalers due to its decongestant activity. Because l-methamphetamine (l-MAMP) is available in OTC form, forensic guidelines require a sample to contain greater than 20% d-methamphetamine (d-MAMP) when classifying results as consistent with illicit MAMP use. Chiral chromatographic analysis is capable of distinguishing between l-MAMP and d-MAMP. This …

Toxicological Assessment Of Zinc Oxide And Titanium Dioxide On Staghorn Coral, Acropora Cervicornis, Katherine E. Meurer

All HCAS Student Capstones, Theses, and Dissertations

Coral reefs are one of the most diverse and biologically significant ecosystems on the planet. However, anthropogenic impacts have led to a global decline in overall reef health in recent years. To address concerns that organic ultraviolet filters in sunscreen may contribute to reduced coral health, the mineral UV filters, zinc oxide (ZnO) and titanium dioxide (TiO₂), have become more common in sunscreen formulas as they are often considered “reef safe” despite limited information on the toxicological effects of these compounds in corals. This study evaluated the effects of exposure to unmodified forms of zinc oxide or titanium …

Amelioration Of Acrolein Effects On The Small Intestine Of Rats By Curcumin And Compound 20, Syntia Engiasa Kwende

Dissertations (2016-Present)

Acrolein is an unsaturated aldehyde which produce chemicals used as an intermediate reactive aldehyde in the chemical industry. The primary component of acrolein, is derived from the incomplete combustion of wood, plastic, fossil fuels, the main component of cigarette smoke, the burning of fats and overheating of oil. The purpose of this research is to investigate whether curcumin and compound 20 prevents the induction of inflammatory and oxidative response caused by acrolein in the small intestine. Curcumin is the yellow pigment, lipophilic polyphenol substance that gives turmeric the medicinal properties. It can also define as the primary bioactive substance in …

Assessment Of Soil, Water Contamination And Land Cover Changes In The Urban And Suburban Watersheds Of Houston, Texas, Felica Rena Davis

Dissertations (2016-Present)

Intense urbanization and increased anthropogenic activity are two important factors contributing to the decline of soil and water quality in Houston watersheds, which poses a great environmental and human health risks. This study, therefore, was designed to: 1) determine nutrient and metal concentrations in soil and water samples along Carpenters Bayou (CaB), Cedar Bayou (CB), Sims Bayou (SB), Spring Creek Bayou (SC) and Vince Bayou (VB), 2) analyze land cover changes in watersheds using Landsat image analysis and 3) evaluate socio-economic characteristics and human health risks for each watershed. Soil and water samples were collected from three different locations with …

Molecular And Behavioral Impacts Of Treated Wastewater Effluent On Fish, Peter Schumann

Theses and Dissertations

Currently, most studies that focus on the sublethal impacts of contaminants of emerging concern (CECs) such as pharmaceuticals utilize a single-compound approach, whereas these compounds always occur as complex mixtures in the environment. Wastewater treatment plants (WWTPs) are a major contributor to the formation of these mixtures as current treatment technologies inadequately remove many chemical pollutants. There is a paucity of knowledge on the neurological impacts due to exposure to complex CEC mixtures resulting from the discharge of treated WWTP effluent into aquatic environments. This knowledge gap leaves incomplete assessments of the hazards and risks from exposure to treated effluent …

Atrazine Levels In Rural Nebraska Counties And Parkinson's Disease, Muhammad Zahid

Capstone Experience

Parkinson's disease (PD) is a multifactorial disorder, connecting both genetic susceptibility and environmental risk factors. Several epidemiological and experimental studies support the evidence that pesticides exposure is positively associated with enhancing neurodegenerative diseases. The high amount of atrazine used in Nebraska and increased PD cases led us to evaluate the association between the long-lived water-soluble pesticide atrazine and PD in Nebraska counties. A person's exposure to atrazine may come from inhalation, dermal absorption, and ingestion. Three types of atrazine data covering 1992 to 2017 were used for this study: applied atrazine, atrazine in surface water, and atrazine in groundwater. In …

Differential Transcriptome Analysis Reveals That Cache Valley Pm2.5 Triggers The Unfolded Protein Response In Human Lung Cells, Morgan Eggleston

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Worldwide, exposure to air pollution is a serious human health threat. Particulate matter (PM) air pollution is a mixture of suspended solid and/or liquid particles and particle size is determined by its aerodynamic diameter. Fine, or “respirable” particles, typically from vehicle emissions, manufacturing, power generation, agriculture, as well as secondary photochemical reactions, are classified as ≤2.5μm in diameter (PM_2.5). Upon inhalation, PM_2.5 particles can reach the lower, more sensitive regions of the lung, enter the bloodstream, and be distributed to other areas in the body. Large-scale epidemiology studies have shown that PM_2.5 air pollution is associated …

Floating Treatment Wetlands For Brackish Waters: Plant Selection And Nutrient Uptake Potential., Andrea Landaverde

All Theses

Brackish water bodies in coastal regions provide critical ecosystem services that support human and environmental health. Anthropogenic activities such as agricultural and industrial activities, construction, urban settlements, and tourism contribute to increased inputs of nitrogen (N) and phosphorus (P) in brackish coastal ecosystems. Excess nutrients can lead to impaired water quality and affect marine organisms. Floating treatment wetlands (FTWs) are a vegetated-base technology used to remove contaminants from water column, that has been mainly studied and applied in freshwater systems. Application of FTWs in brackish systems requires further investigation, as high salinity in brackish waters could result in toxicity to …

Effects Of 2,4-Di-Tert-Butylphenol On Osteogenic And Myogenic Differentiation Of Human Induced Pluripotent Stem Cells, Thanh-Bình Dương

All Theses

Synthetic phenolic antioxidants (SPAs) are a class of compounds used to increase the durability of polymers as well as to increase the shelf-life of food, cosmetics, and other personal care items. Of these SPAs is 2,4-di-tert-butylphenol (2,4-DBP). 2,4-DBP is primarily used in polyethylene crosspolymer pipes, which are now used as a replacement for the traditional copper pipes for household water distribution. However, 2,4-DBP has been found to leach from these pipes into the water, enabling a mode of exposure to humans. 2,4-DBP has been detected in human urine, serum, but more importantly, maternal serum, placenta, and cord blood. …

Particulate Hexavalent Chromium Inhibits Homologous Recombination Repair By Targeting Rad51 Paralogs In Human Lung Fibroblasts., Aggie R. Williams

Electronic Theses and Dissertations

Hexavalent Chromium [Cr(VI)] is a known human lung carcinogen and general health hazard. The mechanism of carcinogenesis remains poorly understood, but chromosome instability (CIN) is the major theory in its carcinogenic mechanism. Homologous recombination (HR) repair is a DNA repair pathway that prevents CIN by repairing DNA double-strand breaks. RAD51, a key mediator protein of HR repair, along with the RAD51 paralogs (RAD51B, C, D, XRCC2, and 3) are required for HR repair. During HR, RAD51 loads and forms a helical nucleoprotein filament structure to promote DNA strand exchange and stimulate pairing activity of DNA. Cr(VI) exposures have been shown …

Blood Lead Levels In Minority Children: A Case Of Environmental Racism, Erick Rivera

Sociology & Criminal Justice Theses & Dissertations

Racial minorities in the United States have suffered from being disadvantaged. Among these disadvantages is environmental racism. This includes minority communities being ‘sacrifice zones’ for toxic waste and being exposed to lead poisoning. The purpose of this study is to examine differences in blood levels between white children and children of color. This research will follow a bivariate model for the first research question, “Do youth of color (under the age of 18) have higher BLLs than white children?” The bivariate model will look at the relationship between ethno-racial group and BLLs. Specifically, an analysis of variance (ANOVA) will be …

Accumulation Of Persistent Organic Pollutants In Marine Mammals: A Case Study On Cetaceans, Pinnipeds, And Sirenians, Alydia Moorhead

All HCAS Student Capstones, Theses, and Dissertations

Persistent organic pollutants (POPs) are lipophilic semi-volatile organic chemicals that present a range of challenges to marine biota, specifically marine mammals that often occupy a high trophic position in the food web. POPs have become a global problem since they have been shown to cause immunologic, teratogenic, carcinogenic, neurological, and reproductive complications in living organisms due to their resistance to biodegradation and their lipophilic nature. Marine mammals can accumulate these toxic substances through direct ingestion, trophic transfer, adsorption, and maternal offloading. They are susceptible to both bioaccumulation and biomagnification of POPs. Accumulation of POPs is affected by many variables, including …