Toxicology Commons^™

Chronic Effects Of Lead Exposure On Atherinops Affinis (Topsmelt): Influence Of Salinity And Organism Age, Erik Joseph Reynolds

Master's Theses

Pb (lead) appears in the environment as a consequence of both natural and anthropogenic processes. Mining, smelting, coal burning, lead acid batteries, and cement manufacturing substantially release Pb into aquatic environments. The goal of this study was to determine the influence of salinity and organism age on chronic toxicity of Pb to Atherinops affinis (topsmelt) in support of development of a species sensitivity distribution (SSD). Species sensitivity distributions assist in ecological risk assessments and establishing quality criteria for contaminants. Three chronic exposure studies were conducted for 28 days in a water flow-through testing system. Survival, standard length, dry weight, and …

Organ-Specific Contribution Of P450 Enzymes To Bioactivation And Acute Respiratory Tract Toxicity Of Naphthalene, Nataliia Kovalchuk

Legacy Theses & Dissertations (2009 - 2024)

Naphthalene (NA) is an omnipresent air pollutant and respiratory toxicant and a possible human lung carcinogen. NA induces cytotoxicity in airways following bioactivation by CYP (P450) enzymes. The overall goal of this study was to examine the relative contributions of hepatic and pulmonary CYPs to bioactivation, disposition and NA-induced pneumotoxicity in vivo. Substantial differences in the expression and enzymatic activity of P450s occur in various organs in human populations, which could modify susceptibility to NA-induced airway damage. The central hypothesis for this study was that NA has the potential to cause lung toxicity in humans and that the metabolism of …

Biomarkers And Metabolic Mechanisms Of Tobacco Smoke-Induced Lung Disease, Matthew Alan Hartog

Legacy Theses & Dissertations (2009 - 2024)

The overall goal of the research conducted in this dissertation is to determine the role of cytochrome (CYP) P450-mediated xenobiotic bioactivation in the development of tobacco smoke-induced lung toxicity. The central hypothesis of this work is that CYP-mediated bioactivation of specific tobacco smoke constituents is an important contributor to the generation of tobacco smoke-induced lung inflammation and injury. The specific aims are 1) to demonstrate that CYP-mediated metabolism contributes to the onset of lung inflammation following tobacco smoke inhalation; 2) to demonstrate that specific tobacco smoke constituents undergo CYP-mediated bioactivation in vivo; 3) to demonstrate that CYP-mediated bioactivation of tobacco …

Understanding The Genotoxicity Of Silver Nanoparticles And The Chemoprevention Of Pomegranate Extract, Sameera Nallanthighal

Legacy Theses & Dissertations (2009 - 2024)

The use of silver nanoparticles (AgNPs) in a wide variety of consumer products (i.e. toothpastes, food containers, dietary supplements and garments) for their antimicrobial properties can lead to potential oral exposure in humans. To enhance their stability, AgNPs are coated with capping agents such as citrate and polyvinylpyrrolidone (PVP). Despite the lack of significant general toxicity based on hematology, blood chemistry and histology evaluations, the potential genotoxic effects of AgNPs cannot be ruled out and have to be addressed. Studies examining the genotoxic risks of AgNPs are needed because genotoxicity is a strong indicator of cancer risk. Here we examined …

Effects Of Antibiotic Treatment On The Expression Of Hepatic And Intestinal Cytochrome P450, Bruno Pereira De Carvalho

Legacy Theses & Dissertations (2009 - 2024)

Expression of metabolic enzymes Cytochrome P450 (CYP) is highly affected by drugs, diseases, age and gender. The Intestinal microflora has been suggested to play a role in regulating CYP expression and antibiotic treatments would lead to changes in level and composition of microbiota in mouse gut. This study aims to analyze CYP expression changes in the liver and small intestine resulted from the reduction of intestinal microflora by antibiotics. Impacts on bile acid signaling were also analyzed for a better comprehension of the mechanisms involved in this modulation. Female C57BL/6J mice (9- to 13-week old) were treated with ampicillin (AMP) …

Endocrine-Disrupting Properties Of Pharmaceuticals And Personal Care Products (Ppcps): An Evaluation Using Aquatic Model Organisms, Manahil Monshi

Wayne State University Theses

Thousands of chemicals have introduced into the environment as a result of human activity since the industrial revolution, and the U.S. Government Accountability Office has estimated that as many as 1,500 new chemical entities are synthesized each year ("Key Issues: Toxic Chemicals - High Risk Issue," 2017). Many of these chemicals are now found in surface water and ground water and can have detrimental effects on environmental health and on human health. This anthropogenic contamination has resulted in the labeling of the diverse array of chemicals found in water, which are not routinely monitored or regulated, as contaminants of emerging …

A Multibiomarker Analysis Of Pollutant Effects On Atlantic Stingray Populations In Florida’S St. Johns River, John Whalen

UNF Graduate Theses and Dissertations

The goal of this study was to examine the potential health effects of organochlorine (OC) and polycyclic aromatic hydrocarbon (PAH) exposure on Atlantic stingray populations in Florida’s St. Johns River (SJR). Special emphasis was placed on identifying OC- and/or PAH-related effects in stingrays from areas of the lower (LSJR) and middle (MSJR) basins shown to possess elevated levels of these compounds, as well as characterizing baseline levels of pollutant exposure in the SJR shipping channel, which may be subjected to dredging in the near future, potentially resuspending and redistributing contaminated sediments and increasing pollutant-associated effects. To accomplish this, we measured …

Mercury Accumulation And Effects In The Brain Of Atlantic Sharpnose Sharks (Rhiszoprionodon Terranovae), Samantha L. Ehnert

UNF Graduate Theses and Dissertations

Sharks often bioaccumulate mercury (Hg) concentrations in their muscle to levels that threaten the health of human consumers. However, few published studies have examined if the high Hg levels seen in shark muscle also occur in the shark brain, or if Hg accumulation affects shark neurophysiology. Therefore, this study examined if shark brains accumulate significant levels of Hg, if Hg accumulation occurs in certain subcomponents of the brain, and if Hg accumulation is associated with oxidative stress effects on the shark central nervous system, with special focus on the Atlantic sharpnose shark (Rhizoprionodon terraenovae). Sharks were collected along …

Immunotherapy Against Drugs Of Abuse, Gianna Raimondi (Class Of 2017)

Writing Across the Curriculum

Current treatments for drug addiction involve classical pharmacological therapy, involving the use of competitive or noncompetitive agonists (full, partial, or inverse) and antagonists. Drugs of abuse enter the brain after crossing the blood-brain barrier rapidly and binding to the proper receptor(s). They are able to do so because they are small and lipid soluble, and produce reinforcing effects by increasing levels of dopamine in brain areas associated with reward. This occurs in specific systems associated with addiction. In the mesolimbic system, neuron cell bodies originate in the ventral tegmental area (VTA) and project to the nucleus accumbens (NAc), amygdala, hippocampus, …

The Effects Of Metolachlor Exposure On The Thp-1 Alveolar Monocyte And Macrophage Function, Jared S. Parmater

Dissertations and Theses @ UNI

The use of additive chemicals such as pesticides has become commonplace in agricultural practices in the Midwestern United States. Metolachlor, an herbicide used to regulate broadleaf weeds in corn and soybeans, is a widely utilized pesticide in the United States. This herbicide is effective in killing broadleaf weeds but has detrimental effects and consequences in non-target organisms. It is a frequent contaminant of ground water due to post application run-off and the air.

Inhalation constitutes one route of exposure, in addition to ingestion, adding to the list of unintended targets and consequences. This route of exposure creates an argument for …

From Disposable Culture To Disposable People: Teaching About The Unintended Consequences Of Plastics, Sasha Adkins

Antioch University Dissertations & Theses

Plastics, the epitome of disposable culture, pose both a toxicological and a spiritual problem. This dissertation examines plastics at a molecular level using the discourse of endocrine disruption, and at a sociological level using the discourses of eco-theology and environmental justice. Adding to the literature on the adsorption of toxicants to plastic marine debris, I demonstrate that certain types of plastic -- those containing mercaptans, such as styrene butadiene block copolymer -- efficiently concentrate methyl mercury from seawater. Further, samples of polycarbonate contributed mercury to seawater. I propose the term plastic-mediated magnification to describe the phenomenon that plastics, along with …

Effects Of Chromium On Mouse Splenic T Lymphocytes And Effects Of Ethanol Exposure During Early Neurodevelopment On Behaviors In Mice, Lu Dai

Theses and Dissertations--Toxicology and Cancer Biology

The dissertation consists of three major projects with the focus on the immunotoxicity of chromium and the behavior disorders caused by early ETOH exposure respectively.

Hexavalent chromium [Cr(VI)] is widely used in various industrial processes and has been recognized as a carcinogen. As the first line of host defense system, the immune system can be a primary target of Cr(VI). T cell population represents a major arm of the immune system that plays a critical role in host anti-tumor immunity. Dysfunction of T cells compromises host anti-tumor immunity resulting in oncogenesis. Using mouse splenic T cells as an in vitro …

Does Timing Of Herbicide Use Influence Rates Of Germination Or Seedling Biomass Of Native Plants Used For Restoration?, Christine Mcmanamen

Graduate Student Theses, Dissertations, & Professional Papers

Invasive plants can negatively impact native grasslands by changing their species composition, productivity, and function. Managers commonly use herbicides as a control method; however, this practice can lead to secondary invasion by other non-native invasive plants, unless measures are taken to promote natives. Because of this, managers often seed native plants after spraying herbicides. There is evidence, however, that chemical control of invasive plants may reduce the effectiveness of subsequent seed-addition treatments, but there is currently little quantitative information on optimal timing between spraying and seeding or on variation in herbicide sensitivity among native plants commonly used in seed mixes. …

Poison In Pink, Sydney V. Cook

Graduate Student Theses, Dissertations, & Professional Papers

Humans slather, spray, mist, and cleanse their bodies with personal care products like lotion, hairspray, cologne, and shampoo every day. Our cupboards are stocked full of them, but few of us understand what is in those jars and bottles. We trust that if it’s on the shelf at the store, it’s safe. However, this is not always the case, and many personal care products contain chemicals that are harmful to human and environmental health.

My multi-disciplinary Environmental Studies thesis project combines evidenced-based research, interviews, nonfiction narrative, and science communication to create part of a book manuscript intended to educate general …

Differential Gene Expression Analysis Of Metolachlor Treated Human Liver Cells By Microarray, Navinder Paul Kaur Brar

Dissertations and Theses @ UNI

Metolachlor is one of the most common pre-emergent pesticides used by Iowa farmers. It is used to control broadleaf weeds and grasses in the fields of corn and soybean. It is a frequent contaminant of groundwater and surface water due to runoff after application. It has been shown to inhibit protein and chlorophyll synthesis in plant cells, but its effect on mammalian cells has not been consistently conclusive. As metolachlor and other herbicides have been shown to be associated with harmful health effects in non-target organisms it is very important to determine a mechanism of action on non-target cells, especially …

Bioanalysis For Cocaine, Opiates, Methadone And Amphetamines Exposure Detection During Pregnancy, Marta Concheiro, Elena Lendoiro, Ana De Castro, Eva Gonzalez-Colmenero, Ana Concheiro-Guisan, Patricia Penas-Silva, Manuel Macias-Cortina, Angelines Cruz-Landeira, Manuel Lopez-Rivadulla

Publications and Research

Drug exposure during pregnancy constitutes a major legal issue and public health concern. Drug and metabolite determination in biological matrices from mother and newborn is an objective indication of prenatal drug exposure. However, limited data are available regarding the interpretation of these analytical results in terms of window of detection and degree of exposure. We collected paired maternal hair, meconium, placenta and umbilical cord from 727 mother-newborn dyads. We analyzed these specimens by liquid chromatography tandem mass spectrometry for the determination of cocaine, opioids, methadone and amphetamines, and compared the analytical results from the four different matrices. The cases were …

Identification Of “Kratom” (Mitragyna Speciosa) Alkaloids In Commercially Available Products, Julia Grzymkowski, Michelle R. Peace, Justin Poklis

Undergraduate Research Posters

“Kratom” is the common name for the botanical mitragyna speciosa. It is a tree native to Southeast Asia in which leaves contain the psychoactive alkaloids mitragynine and 7-hydroxymitragynine. Kratom is often ingested as teas, chewed, or smoked. It acts as a stimulant in small doses and as an opioid in large doses. Overdoses can result in vomiting, seizures, and death. Recently the Drug Enforcement Agency (DEA) placed Kratom on Schedule 1, but, due to public outcry, it was almost immediately removed.

Eleven kratom based products were obtained from various tobacco shops, “headshops” and via the internet including: Choice brand …

Molecular Measurement Of Toxicity In Fish; Case Examples And Policy Implications, Jessica A. Freedman

Senior Honors Projects

Stormwater and oil are common urban contaminants that can be harmful to fish species. One way of recognizing exposed and impaired fish is by monitoring gene expression and gene induction. This study focused on the identification and validation of reference genes for measuring contaminant-induced changes in gene expression due to urban influence. In this study, reference genes (which are genes used to normalize data and remain consistent in varying exposures regardless of organism and tissue type) were established. Six genes were identified as reference genes (ef1a, wdtc1, mtm1, spop, rxrba and tuba1) from a longer list of potential …

Nanoparticle Toxicity And Molecular Mechanisms In Fish: A Case Study With Silver Nanoparticles, Jiejun Gao

Open Access Dissertations

Nanoparticles (NPs) are widely used in a myriad of commercial and industrial products making their entry to the environment a likely event. NPs have unique physical-chemical properties that result from their small size and high surface area to volume ratio, making them highly reactive and potentially toxic. In Chapter 1, we summarize the effects and mechanisms of metal-based NPs on the vascular system. In vitro studies have shown that NPs are anti-angiogenic because they cause inflammation, oxidative stress, and apoptosis of endothelial cells resulting in increased permeability and decreased proliferation and migration. Whole animal studies examining the effects of NPs …

Gonadal Intersex In Teleosts: Mechanisms, Molecular Biomarkers And Diagnostic Assays, Ahmed M.E. Abdel-Moneim Mohamed

Open Access Dissertations

Natural and synthetic estrogenic and androgenic compounds are continuously released into aquatic ecosystems. Exposure of teleost fishes to these contaminants can negatively impact sex differentiation and reproductive output. Specifically, development of gonadal intersex in gonochoristic (fixed sex) fish species has been studied extensively in relation to exposure to this class of compounds. The main objectives of this dissertation were to: 1) conduct field and laboratory studies to investigate the molecular signaling pathways behind the development of gonadal intersex; and 2) establish molecular biomarkers and assays for testing the ability of environmental pollutants to develop this condition using a battery of …