Toxicology Commons^™

In Vitro Assessment Of Deleterious Impacts Of Organomodified Nanoclays And Their Incinerated Byproducts On Human Cells, Andrew Philip White

Graduate Theses, Dissertations, and Problem Reports (ETD)

Organomodified nanoclays (ONCs: i.e., smectite clays with different organic coatings), act as nanofillers in applications ranging from automotive, to aerospace, and biomedical implementations. Because of their large utilization, ONC industry is projected to be a U.S. $3.3 billion industry by 2023. However, emerging studies showed that ONCs and ONC-nanocomposites could harbor health risks upon pulmonary exposure and along their life cycle, namely during synthesis, handling, use, manipulation, and disposal. Specifically, the potential for exposure and adverse effects on human health primarily includes release of dry particulate during handling, manipulation, release during use, and release during the end-of-life disposal or recycling …

Development Of Novel Analytical Methods For Detection And Determination Of Tamoxifen In Oral Fluid And Discrimination Between Regioisomeric Aromatase Inhibitors For Doping Control Purposes, Brooke A. Sutton

Online Theses and Dissertations

The use of SERMs (Selective Estrogen Receptor Modulators) – most notably the drug Tamoxifen – has significantly increased among athletes over the past decade to enhance athletic performance and/or negate certain side effects of using anabolic steroids. This “doping” is always banned by WADA (World Anti-Doping Agency) for all athletes, but SERMs can naturally increase testosterone production so they are a tempting alternative to using steroids or androgenic supplements that can cause significant health problems (e.g. acne, breast development, frequent urge to urinate, low libido, etc.). Similarly, the use of AIs (Aromatase Inhibitors) has also increased among athletes for identical …

Environmental Contaminants, Parasitism, And Neoplasia In White Perch Morone Americana From Chesapeake Bay, Usa, Mark Arnold Matsche

Graduate Theses, Dissertations, and Problem Reports (ETD)

White perch are an abundant demersal fish species in freshwater and oligohaline habitats of the Chesapeake Bay. An avoidance of salinity > 12-15 ppt generally restricts the distribution and movements of fish to within tributaries in the mid to lower Bay, which over time has resulted in the formation of at least three separate stocks in Chesapeake Bay. Sub-populations of white perch that are partially isolated may serve as sentinels of the conditions or stressors in the tributaries in which they reside. Fish are exposed to a variety of environmental contaminants and other anthropogenic stressors that can vary in magnitude based …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Development Of A Method For The Detection And Quantification Of Various Benzodiazepines And Z-Drugs In Human Blood And Qualitative Identification In Urine Samples Using Liquid Chromatography Mass Spectrometry (Lc-Ms/Ms), Haley Michel

Williams Honors College, Honors Research Projects

This method developed in the toxicology department at the Cuyahoga County Medical Examiner’s Office (CCMEO) detects 40 benzodiazepines and metabolites along with several z-drugs in blood and urine by liquid chromatography tandem mass spectrometry. A sample amount of 0.5 mL was used to detect analytes in postmortem drug facilitated sexual assault and impaired driving cases. Twenty-nine analytes met criteria for quantification while the remaining 14 were used as qualitative indicators. Bias and precision results for quality controls met criteria, staying within ±15% except for clonazolam and etizolam which were within ±20%. Quantitative reporting criteria which included dilution integrity was met …

On Site Comparison Of The Osha 42, Asset Ez4-Nco, Iso-Chek, Dan And Cip10 Methods For Measuring Toluene Diisocyanate (Tdi) At A Polyurethane Foam Factory, Simon Aubin, El Mekki Hamdi, Audrey Joly, Philippe Sarazin, Jacques Lesage, Livain Breau, Mark Spence, Sébastien Gagné

Études primaires

Because of the semi-volatile nature of diisocyanates (being airborne in both physical vapor and particulate phases), their high reactivity and low occupational exposure limits, diisocyanate exposure evaluation has been challenging for industrial hygienists and laboratories. The objective of this study was to compare the toluene diisocyanate (2,4 and 2,6 isomers, TDI) concentration measured by five methods in a flexible polyurethane foam factory using different collection or derivatization approaches. The methods used were: OSHA 42 modified (filter, 1-(2-pyridyl)piperazine) (OSHA), Asset EZ4-NCO (denuder and filter, dibutylamine) (Asset), Iso-Chek (double-filter, 9-(N-methylaminomethyl) anthracene and 1,2-methoxyphenylpiperazine), DAN (filter, 1,8-diaminonaphthalene), and CIP10 (centrifugation, 1,2-methoxyphenylpiperazine). Particle real-time …

The Exploration Of Nanotoxicological Copper And Interspecific Saccharomyces Hybrids, Matthew Joseph Winans Phd

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nanotechnology takes advantage of cellular biology’s natural nanoscale operations by interacting with biomolecules differently than soluble or bulk materials, often altering normal cellular processes such as metabolism or growth. To gain a better understanding of how copper nanoparticles hybridized on cellulose fibers called carboxymethyl cellulose (CMC) affected growth of Saccharomyces cerevisiae, the mechanisms of toxicity were explored. Multiple methodologies covering genetics, proteomics, metallomics, and metabolomics were used during this investigation. The work that lead to this dissertation discovered that these cellulosic copper nanoparticles had a unique toxicity compared to copper. Further investigation suggested a possible ionic or molecular mimicry …

Exosomes As Systemic Mediators Of Nanotube Induced Neurotoxicity, Christopher G. Canal

Theses and Dissertations

Extra-pulmonary effects of nanoparticle inhalation have been well documented; however, mechanisms for conveying peripheral bioactivity remain elusive. Recent studies point to indirect molecular mediators shed into the circulation. Protein and lipid alternatives to cytokines or chemokines have been proposed, yet the diversity among responses suggests a broader assemblage of factors. Recently we have proposed proteolytic fragment peptides as an additional source of bioactivity, which interestingly were significantly associated with exosomal proteins after enrichment analysis. Here we tested whether modeled exposure to multi-walled carbon nanotubes (MWCNT) could alter the composition and bioactivity of circulating exosomes. Male C57BL/6 mice were exposed by …

Surfacant Contamination Alters Freshwater Phytoplankton Community Composition, William H. Hodge

College of Graduate Studies: Theses & Dissertations

Pollution from cleaning and personal care products enter freshwater systems and have the potential to alter phytoplankton abundance and diversity. Alkyl polyglucoside (APG), a widely used foaming agent in detergents, decreases phytoplankton abundance, but whether sensitivity to APG is affected by taxonomic identity and/or the presence of competitors is unclear. Establishing taxon-specific responses to APG is important, because taxa differ in nutritional quality and palatability for zooplankton grazers.

Chapter one describes comparisons between how individual phytoplankton communities respond to the same range of APG concentrations to test hypotheses that: 1) chemical concentration determines how individual taxa respond to APG; 2) …

On-Site Comparison Of The Osha 47, Asset Ez4-Nco, Iso-Chek, Dan, And Cip10 Methods For Measuring Methylene Diphenyl Diisocyanate (Mdi) At An Oriented-Strand Board (Osb) Factory, Simon Aubin, El Mekki Hamdi, Audrey Joly, Philippe Sarazin, Jacques Lesage, Livain Breau, Mark Spence, Sébastien Gagné

Études primaires

Diisocyanates are occupational contaminants and known sensitizers causing irritation (skin and respiratory tract) as well as occupational asthma. Because of their physicochemical properties (semi-volatile and high reactivity) and low occupational limits, diisocyanate exposure evaluation is still a challenge nowadays for industrial hygienists and laboratories. The objective of this study was to compare the methylene diphenyl diisocyanate (MDI) concentrations measured by five methods using different collection or derivatization approaches in an oriented-strand board (OSB) factory. The methods used were: OSHA 47 (filter, 1-(2-pyridyl)piperazine) (OSHA), Asset EZ4-NCO (denuder and filter, dibutylamine) (Asset), Iso-Chek (double-filter, 9-(N-methylaminomethyl) anthracene and 1,2-methoxyphenylpiperazine), DAN (filter, 1,8-diaminonaphthalene), and …

The Combined Effects Of Chemicals Used In Textile Processing On Plankton Communities., Diana Wilson

Honors College Theses

Industrial discharge, such as textile effluent, is a major source of chemical mixtures to surface waters. The effects of these mixtures on interacting aquatic organisms can be difficult to predict. We hypothesized that individual chemical effects on phytoplankton and a zooplankton grazer are altered by the presence of other chemicals in mixtures. Microcosms containing a phytoplankton food source (Chlorella sp.) and a zooplankton grazer (Daphnia magna) were exposed to THPC, ammonium, and hydrogen peroxide in a fully crossed design in a greenhouse for one week. Phytoplankton abundance was quantified and zooplankton response was measured as mortality and …