Toxicology Commons^™

Immunomodulatory Effects Of Diesel Exhaust Particles, Ashley Kay Masterson

Boise State University Theses and Dissertations

Diesel exhaust particles (DEP) represent a key component of particulate matter pollution and a serious cardiopulmonary health risk, as these particles have been associated with increased morbidity and mortality following exposure. In this study, we investigated the immunomodulatory properties of DEP on helper T cells by measuring changes in activation, cytokine production, and viability. The expression of CD40L, a key regulatory protein, was increased by DEP in the absence of physiologic stimuli without parallel increases in the expression of CD25 and CD69 activation markers. Additional studies utilizing a variety of T cell stimuli, including T cell receptor signaling and CD28 …

Monitoring Of Heavy Metal Loading Into The Wetlands South Of Lake Victoria Basin, Nothern Tanzania, M K D Mutakyahwa, J R Ikingura, G Y S Mtui

Tanzania Journal of Science

The paper discusses sources, concentrations and physicochemical parameters of heavy metals of environmental concern in the wetlands of Lake Victoria basin in Tanzania. The metals investigated include copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), nickel (Ni), arsenic (As), manganese (Mn), cobalt (Co) and mercury (Hg). These metals are released into the wetlands via weathering and erosion of rock formations, mining operations and industrial activities, discharge of municipal and domestic waste, and use of agrochemicals. The levels of these heavy metals in soil, sediment, water, and biota differ. Wetlands impacted by gold mining activities in the South Lake …

Effects Of The Polycyclic Musk Hhcb On Individual- And Population-Level Endpoints In Potamopyrgus Antipodarum, Signe Pedersen, Henriette Selck, Daniel Salvito, Valery E. Forbes

Valery Forbes Publications

Although the polycyclic musk 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran (HHCB) is frequently detected in aquatic sediments, very little is known about its effects on sediment-feeding organisms. Effects of sediment-associated HHCB on growth, feeding rate, survival and reproduction in the gastropod Potamopyrgus antipodarum were measured in the laboratory. Snails were exposed to six nominal HHCB concentrations: 0, 0.1, 1, 10, 30 and 100 μg g−1 dry weight (dw) sediment. Adult survival and growth were not affected by HHCB. However, juvenile growth and survival, reproduction, time to first reproduction and adult feeding rate were more sensitive endpoints and declined with increasing HHCB concentration. Individual-level endpoints for …

In Vitro Toxicity Of Silver Nanoparticles In Human Lung Epithelial Cells, Christina R. Kearns

Theses and Dissertations

Nanotechnology is quickly becoming incorporated into everyday products and uses. Silver nanoparticles, specifically, are being used in commercial products, to include aerosols. The purpose of this research was to determine whether silver nanoparticles are toxic to human lung epithelial cells. Different types (coated vs. uncoated), concentrations (10, 50, 100, and 200 µg/mL) and sizes (coated 5 and 80nm, uncoated 10 and 80nm) of silver nanoparticles were used during this study. Toxicity measurements were completed through in vitro techniques. Another study was also completed on toxicity mechanisms by measuring the reactive oxygen species (ROS) generated. Results showed that silver nanoparticles induce …

The Amphipod Orchomenella Pinguis — A Potential Bioindicator For Contamination In The Arctic, Lis Bach, Valery E. Forbes, Ingela Dahllöf

Valery Forbes Publications

Indigenous organisms can be used as bioindicators for effects of contaminants, but no such bioindicator has been established for Arctic areas. Orchomenella pinguis is a benthic amphipod, ubiquitous in the Arctic and can be found in high numbers. We collected O. pinguis at sites with different contamination levels. Population characteristics (body length distribution, average dry weight and amphipod organic content) were related to sediment contaminant concentrations, in order to identify suitable endpoints for using this species as a bioindicator. We show that O. pinguis was prevalent in both clean and contaminated areas, easy to sample and that its population characteristics …

Genetic And Non-Genetic Factors That Cause Inter-Individual Variations In Cyp2a13 Gene Expression, Hong Wu

Legacy Theses & Dissertations (2009 - 2024)

The overall goal of this dissertation is to investigate the mechanisms underlying the large interindividual variations in susceptibility to lung carcinogenesis. We focused on CYP2A13, a respiratory tract-specifically expressed enzyme, which is the most efficient P450 towards bioactivation of a tobacco-related carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The expression level of CYP2A13 varies substantially among human lung samples. Our central hypothesis is that CYP2A13 expression level is affected by both genetic regulators and non-genetic factors. The specific aims are 1) to identify the mechanisms underlying the decreased allelic expression of a CYP2A13 allele (7520C>G); 2) to identify frequent single-nucleotide polymorphisms (SNPs), associated …

Application Of Multiple Mass Spectrometric Techniques In The Isolation, Determination And Characterisation Of The Marine Toxins; Azaspiracid, Keith O'Callaghan

Theses

The Azaspiracids are a class of polyether marine biotoxins that present a significant health risk to consumers of shellfish. Since their discovery in the late 1990s several human intoxications have been reported, and traced to Irish shellfish farms resulting in closures or harvest rejections. As such incidents involving azaspiracid shellfish poisoning have a major socio-economic impact on communities that rely on shellfish farming revenues.

Recent evidence suggests that azaspiracid poisoning events may become more commonplace. With this increased risk the understanding of azaspiracids mode of action and biological targets becomes crucial. To support these endeavours effective analytical methods need to …

Evaluating Acute Toxicity Of Cadmium To Chironomid Using Hemoglobin As A Molecular Biomarker, Jun Taek Oh

Seton Hall University Dissertations and Theses (ETDs)

Effects of cadmium (Cd), a heavy metal contaminant, on hemoglobin were investigated in aquatic midge fly larvae of the Family, Chironomidae. In this study, chironomid populations from one polluted site, Kearny Marsh, New Jersey, two reference sites, North East Creek, and Bass Harbor, ME, and a laboratory population were taxonomically identified and tested for their sensitivity to Cd. Heavy metals in tissue, water and sediment were analyzed using Atomic Absorption Spectroscopy. Water quality at each site was assessed by measuring pH, dissolved oxygen (DO), oxidation-reduction potential ( eH), salinity and temperature. Hemoglobin proteins in individual larvae were easily detected using …

Effect Of Increased Carbon Dioxide Levels On Urushiol Production In Toxicodendron Radicans And Toxicodendron Toxicarium, Meredith Gilbert

Theses and Dissertations

It is hypothesized that global warming is at least partially due to increased greenhouse gases, one of which is carbon dioxide. An increase in atmospheric carbon dioxide has been shown to stimulate higher rates of plant productivity, including the production of plant toxins like urushiol. Urushiol, a secondary plant compound produced in members of the Anacardiaceae family, causes dermatitis in sensitive individuals. An increase in urushiol production could increase the reactivity of certain individuals to plants like poison oak and poison ivy. To determine how elevated levels of atmospheric carbon dioxide would effect urushiol production, 16 samples of poison ivy …