Toxicology Commons^™

Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang

Doctoral Dissertations

"Manufactured nano-/micro-materials (MNMs) have been widely used and their interactions with niche biological environment are highly concerned for both of their biohazardous and bioactive effects, whereas no available comprehensive evaluations or regulations have been provided yet. This dissertation thus focuses on three major aspects: 1) fundamental toxicity understandings of a typical MNMs (zinc oxide nanoparticles), 2) bioactivity evaluations of representative bioactive MNMs, and 3) development of novel micro-probes for high spatial resolution monitoring. Firstly, the NP's concentration, irradiation, hydrodynamic size, and the localized pH, ionic strength, NP zeta-potential as well as dissolved oxygen levels were found correlated with the production …

Consequences Of Developmental Lead (Pb2+) Exposure On Reproductive Strategies In Drosophila, Elizabeth Kathleen Peterson

Legacy Theses & Dissertations (2009 - 2024)

Anthropogenic lead (Pb) pollution is ubiquitous in the environment and a risk factor for both human and wildlife health. Pb exposure has the potential to alter reproductive strategies with respect to mate choice and reproductive output. This could be especially deleterious if these changes disrupt adaptive behavioral and reproductive life history strategies. Therefore, the overall aim of this body of work was to examine the consequences of developmental Pb exposure on reproductive strategies, using Drosophila melanogaster as a model system. In all experiments, D. melanogaster were reared from egg stage to adulthood in either control or leaded medium and were …

Development Of A Dreissena Bioassay To Assess The Toxicity Of Contaminants Across Two Life-History Stages, Caroline Joyce Addis

Wayne State University Theses

Dreissenid mussels (Dreissena polymorpha and D. bugensis) have rapidly become widespread and ubiquitous in North America since their introduction into the Great Lakes in the 1980s. The resulting environmental and economic impacts of their invasion have been extensive, negatively affecting biodiversity and costing millions of dollars in control efforts and damage to power generation and water treatment facilities. Although dreissenids are often associated with negative impacts, they may present a practical tool for toxicology studies. The typically sessile behavior of the benthic adults coupled with the planktonic nature of the veligers allow for a more complete evaluation of water quality …

The Influence Of Abiotic Factors On The Uptake And Elimination Of 3-Trifluoromethyl-4-Nitrophenol By Larval Sea Lamprey (Petromyzon Marinus), Benjamin Livingston Hlina

Theses and Dissertations (Comprehensive)

The backbone of sea lamprey (Petromyzon marinus) control in the Great Lakes is the use of the piscicide, 3-trifluoromethyl-4-nitrophenol (TFM), which is applied to streams containing larval sea lampreys. However, TFM effectiveness can be influenced by abiotic factors such as pH and temperature, which fluctuate daily and seasonally. The objectives of this thesis were to evaluate the influence of pH, temperature, and season on the toxicity, uptake, and elimination of TFM by larval sea lamprey. Radio-labeled TFM (¹⁴C-TFM) was used to determine how TFM uptake rates varied at different water pHs or temperatures during exposure to …

The Role Of Oxidative Stress In The Mechanisms Of Ammonia-Induced Brain Swelling And Tolerance In The Goldfish (Carassius Auratus), David F. Jones Lisser Mr.

Theses and Dissertations (Comprehensive)

Toxic build-ups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). The mechanisms of ammonia-induced brain swelling and tolerance remain elusive, but several studies have suggested a role for reactive oxygen species (ROS), which may damage proteins and lipids in the plasma membrane of astrocytes in the brain. As a result, osmotic gradients across cell membranes may be altered leading to water uptake by astrocytes and swelling. While a role for ROS has been proposed in mammals, no studies have addressed this question in …

Nickel And Copper Mixture Toxicity To Daphnia In Soft Water, Prachi Deshpande

Theses and Dissertations (Comprehensive)

Industrially important metals, such as Cu and Ni, sometimes are present at elevated concentrations in lakes, including those in the Sudbury, ON region. Although they are essential metals, their divalent-cation state (Cu²⁺ and Ni²⁺) can be toxic at high concentrations in the water. The free-ion toxicity of each of these metals has been studied in isolation, but rarely as a mixture. The economic importance of Cu²⁺ and Ni²⁺ makes them essential to study in the context of mixture toxicity. The objectives were to: (1) determine Cu and Ni mixture toxicity to Daphnia through acute LC50 …

Do Toxicity Modifying Factors Influence Acute Or Chronic Toxicity Of Thulium To Hyalella Azteca?, Alexandria H. Loveridge

Theses and Dissertations (Comprehensive)

The industrial demand for rare earth elements (REEs) is growing and as a result, environmental exposure is a concern. Very little is understood about the toxicity of REEs in aquatic environments. The objective of this research is to evaluate the acute and chronic toxicity of Tm and to also understand the toxicity modifying influence of dissolved organic matter (DOM) and cationic competition (Ca2+, Mg2+ and Na+). Furthermore, the aim of this study was to determine linkages between Tm bioaccumulation, growth and survival during chronic exposures. Standard methods (Environment Canada) were followed for both 96h acute and 14d chronic tests, in …

The Role Of Renal Replacement Therapy In The Management Of Pharmacologic Poisonings, Aibek E. Mirrakhimov, Aram Barbaryan, Adam Gray, Taha Ayach

Internal Medicine Faculty Publications

Pharmacologic toxicities are common and range from mild to life-threatening. The aim of this study is to review and update the data on the role of renal replacement therapy (RRT) in the management of various pharmacologic poisonings. We aim to provide a focused review on the role of RRT in the management of pharmacological toxicities. Relevant publications were searched in MEDLINE with the following search terms alone or in combination: pharmacologic toxicity, hemodialysis, hemofiltration, renal replacement therapy, toxicology, poisonings, critical illness, and intensive care. The studies showed that a pharmacologic substance should meet several prerequisites to be deemed dialyzable. These …

Heavy Metal Accumulation In Urban Soil: A Phytoextraction Method Review, Diane M. Nelson

Dissertations, Master's Theses and Master's Reports

Lead (Pb), cadmium (Cd), and arsenic (As) are three common non-essential heavy metals found in urban soils and can prove toxic to animals, humans, and some plants at low concentrations. The main exposure pathways of heavy metals in humans are through ingestion and inhalation of soil particles and ingestion of contaminated food. When dealing with contaminated soil in urban environments, activities like urban gardening can increase the likelihood of these exposure pathways, so heavy metal toxicity from contaminated soil can become a greater risk with the increased interest in urban agriculture. The US EPA created target concentrations for these heavy …

Validation Of Type 2 Diabetes Risk Variants Identified By Genome-Wide Association Studies In Northern Han Chinese, Ping Rao, Yong Zhou, Siqi Ge, Anxin Wang, Xinwei Yu, Mohamed Ali Alzain, Andrea K. Veronica, Jing Qiu, Manshu Song, Jie Zhang, Hao Wang, Honghong Fang, Qing Gao, Youxin Wang, Wei Wang

Research outputs 2014 to 2021

Background:

More than 60 genetic susceptibility loci associated with type 2 diabetes mellitus (T2DM) have been established in populations of Asian and European ancestry. Given ethnic differences and environmental factors, validation of the effects of genetic risk variants with reported associations identified by Genome-Wide Association Studies (GWASs) is essential. The study aims at evaluating the associations of T2DM with 29 single nucleotide polymorphisms (SNPs) from 19 candidate genes derived from GWASs in a northern Han Chinese population.

Method:

In this case-control study, 461 T2DM-diagnosed patients and 434 controls were recruited at the Jidong oil field hospital (Hebei, China) from January …

Exploration Of The Srx-Prx Axis As A Small-Molecule Target, Murli Mishra

Theses and Dissertations--Toxicology and Cancer Biology

Lung cancer is a leading cause of cancer-related mortality irrespective of gender. The Sulfiredoxin (Srx) and Peroxiredoxin (Prx) are a group of thiol-based antioxidant proteins that plays an essential role in non-small cell lung cancer. Understanding the molecular characteristics of the Srx-Prx interaction may help design the strategies for future development of therapeutic tools. Based on existing literature and preliminary data from our lab, we hypothesized that the Srx plays a critical role in lung carcinogenesis and targeting the Srx-Prx axis or Srx alone may facilitate future development of targeted therapeutics for prevention and treatment of lung cancer. First, …

Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis

Theses and Dissertations--Plant and Soil Sciences

Engineered nanomaterials (ENMs) have become ubiquitous in consumer products and industrial applications, and consequently the environment. Much of the environmentally released ENMs are expected to enter terrestrial ecosystems via land application of nano-enriched biosolids to agricultural fields. Among the organisms most likely to encounter nano-enriched biosolids are the key soil bacteria known as plant growth promoting rhizobacteria (PGPR). I reviewed what is known concerning the toxicological effects of ENMs to PGPR and observed the need for high-throughput methods to evaluate lethal and sublethal toxic responses of aerobic microbes. I addressed this issue by developing high-throughput microplate assays which allowed me …

The Effects Of Manufactured Nanomaterial Transformations On Bioavailability, Toxicity And Transcriptomic Responses Of Caenorhabditis Elegans, Daniel L. Starnes

Theses and Dissertations--Plant and Soil Sciences

In recent decades, there has been a rapid expansion in the use of manufactured nanoparticles (MNPs). Experimental evidence and material flow models predict that MNPs enter wastewater treatment plants and partition to sewage sludge and majority of that sludge is land applied as biosolids. During wastewater treatment and after land application, MNPs undergo biogeochemical transformations (aging). The primary transformation process for silver MNPs (Ag-MNPs) is sulfidation, while zinc oxide MNPs (ZnO-MNPs) most likely undergo phosphatation and sulfidation. Our overall goal was to assess bioavailability and toxicogenomic impacts of both pristine, defined as-synthesized, and aged Ag- and ZnO-MNPs, as well as …

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

Identification Of Methylene Diphenyl Diisocyanate Thermal Degradation Products In A Generation Chamber By Liquid Chromatography Coupled With Tandem Mass Spectrometry, Sébastien Gagné, Yves Cloutier

Études primaires

Isocyanate thermal degradation characterization by liquid chromatography coupled with electrospray tandem mass spectrometry has been performed to elucidate the methylene diphenyl diisocyanate (MDI) thermal degradation structure emitted in a generation chamber using a temperature between 50°C and 180°C to produce MDI vapors. [M+H]⁺ ions containing an isocyanate functional group were studied by tandem mass spectrometry. The [M+H]⁺ ion analyses based on the combination of full scans and precursor ion scans were useful for identifying all structures. The compounds emitted were identified and validated as a mixture of compounds containing amine and isocyanate functions. Residual MDI, methylene diphenyl amino-isocyanate, …

Implementation And Evaluation Of An Analytical Method For A Novel Derivatizing Agent To Measure 4,4'-Methylene Diphenyl Diisocyanate Atmospheres, Silvia Puscasu, Simon Aubin, Mark Spence, Sébastien Gagné

Études primaires

Accurate measurement of 4,4'-methylene diphenyl diisocyanate (MDI) atmospheres is a challenge since the molecule is both chemically reactive and likely to be present in aerosol form when heated and sprayed because of its low vapor pressure. Meeting this challenge requires optimizing both the sampling device used and the derivatization agent employed to stabilize the isocyanate functional group. This study describes the use of a novel derivatization reagent for isocyanate sampling to address the challenge of MDI aerosol exposure sampling. Like most conventional derivatizing agents for isocyanates, 1,8-diaminonapthalene (DAN) reacts with isocyanate functional groups to form a urea. However, unlike other …

The Sublethal Physiological Effects Of Exposure To Copper And Silver Mixtures On Rainbow Trout (Oncorhynchus Mykiss), Wesley Truong

Theses and Dissertations (Comprehensive)

The mechanisms behind metal-metal interactions in freshwater environments are currently not well understood. Freshwater environments consist of many different types of metals, from those naturally present such as copper (Cu) and those that originate from anthropogenic sources like silver (Ag). Both Cu and Ag use apical sodium (Na⁺) channels for uptake into the gills of freshwater fish. In the gills, the mechanisms of Cu²⁺ and Ag⁺ toxicity appear to be similar to one another, which is by inhibiting Na⁺ /potassium (K⁺)- adenosine triphosphatase (NKA) and carbonic anhydrase (CA). Inhibition of NKA and CA …

The Smell Of Hopelessness, Juline Cariba Rachel Party

Capstones

Rafts of sargassum seaweed kilometers wide have been invading the Caribbean for more than five years, but 2015 was the worst. Tons of seaweed stretch from Texas south to Trinidad and Tobago, with the Lesser Antilles suffering the most damage. Residents near beaches are exposed to an insidious and pernicious danger, scientists say, from fumes that smell like rotten eggs, emitted by the decaying algae. The odor also drives tourists away from beaches and restaurants, and the tourism economy is collapsing.Amid the algae crisis, an elderly woman, Virginie Mark, is trying to survive. She struggles with her health, finances and …

Lead Exposure In Children Through Water And Soil, Sravya Maru

Environmental Management & Risk Assessment (PH 560)

Lead is a metal which has the ability to spread in the earth’s crust and has corrosive property. It is a naturally occurring metal which is soft in nature. Lead exposure in children is through various pathways and the major concentrated sources are the soil and drinking water. Children are most susceptible to lead exposure is due to their growing/developing bodies which are very sensitive to lead. Lead poisoning in children is a preventable environmental disease affecting many children around the world. This paper discusses how soil and water plays a major role in lead exposure to children’s routine life. …

Comparative Aquatic Toxicity Of A Commercial Naphthenic Acid And Processes For Mitigating Risks, Ciera Kinley

All Theses

Comparative toxicity data can inform predictions of relative risk, and can be used to implement strategies for altering exposures to mitigate risk. Naphthenic acids (NAs) are a complex group of carboxylic acids that naturally occur in petroleum sources and energy-derived process waters (e.g. refinery effluents and oil sands process affected waters). These compounds are relatively persistent in water and can be a source of toxicity to aquatic organisms. In the first experiment of this thesis, responses of sentinel aquatic organisms to 7-d exposures of commercial (Fluka) NAs were measured (in terms of acute toxicity) to discern relative sensitivities. In terms …