Toxicology Commons^™

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 …

Hybrid Computational Toxicology Models For Regulatory Risk Assessment, Prachi Pradeep

Dissertations (1934 -)

Computational toxicology is the development of quantitative structure activity relationship (QSAR) models that relate a quantitative measure of chemical structure to a biological effect. In silico QSAR tools are widely accepted as a faster alternative to time-consuming clinical and animal testing methods for regulatory risk assessment of xenobiotics used in consumer products. However, different QSAR tools often make contrasting predictions for a new xenobiotic and may also vary in their predictive ability for different class of xenobiotics. This makes their use challenging, especially in regulatory applications, where transparency and interpretation of predictions play a crucial role in the development of …

Characterization Of Metallic And Semimetallic Oxide Nanoparticles In Industrial Wastewater And Associated Toxicity, Gary Roth

Legacy Theses & Dissertations (2009 - 2024)

Engineered nanomaterials (ENMs) play an increasing role in manufacturing and consumer products. Currently, there is no standard approach to studying ENM toxicity, and a growing body of literature suggests that ENMs may have toxicity differing from similar compounds in bulk or dissolved form. I examined ENMs used in the semiconductor manufacturing process called chemical-mechanical planarization (CMP) for their properties, removal in the wastewater treatment system (WWT), in-vitro toxicity, and location post-inhalation in-vivo. It was found that ENMs in CMP slurries have morphology determined by their elemental composition, but assessment of size and concentration can differ substantially between accepted techniques. Particles …

Nanoceria Exposure To Kidney Beans (Phaseolus Vulgaris): Implications On Plant Physiology, Nutrition And Their Transfer To Next Trophic Level, Sanghamitra Majumdar

Open Access Theses & Dissertations

Previous studies investigating the effects of cerium oxide nanoparticles (nanoceria, nCeO2) on plants have primarily focused on the physiological and biochemical changes at early growth stages. Comprehensive information on the effects of nCeO2 through the entire life cycle of plants and the nutritional quality of the edible tissues is limited. No studies have been reported on the interactions between nCeO2 and common beans (Phaseolus vulgaris). Common beans are leguminous crops, which are societally important due to their nutritional benefits. The beans are rich in proteins and essential nutrients like folate, iron, zinc, molybdenum and magnesium, and are consumed worldwide. This …

Cip10 Optimization For 4,4-Methylene Diphenyl Diisocyanate Aerosol Sampling And Field Comparison With Impinger Method, Silvia Puscasu, Simon Aubin, Yves Cloutier, Philippe Sarazin, Huu Van Tra, Sébastien Gagné

Études primaires

4,4-methylene diphenyl diisocyanate (MDI) aerosol exposure evaluation in spray foam insulation application is known as being a challenge because the spray foam application actually involves a fast-curing process. Available techniques are either not user-friendly or are inaccurate or not validated for this application. To address these issues, a new approach using a CIP10M was developed to appropriately collect MDI aerosol in spray foam insulation while being suitable for personal sampling. The CIP10M is a commercially available personal aerosol sampler that has been validated for the collection of microbial spores into a liquid medium. Tributylphosphate with 1-(2-methoxyphenyl)piperazine (MOPIP) was introduced into …

Comparison Between The Asset Ez4 Nco And Impinger Sampling Devices For Aerosol Sampling Of 4,4′-Methylene Diphenyl Diisocyanate In Spray Foam Application, Silvia Puscasu, Simon Aubin, Yves Cloutier, Philippe Sarazin, Huu Van Tra, Sébastien Gagné

Études primaires

4,4′-methylene diphenyl diisocyanate (MDI) aerosol exposure evaluation in spray foam insulation application is known to be a challenge. Current available techniques are either not user-friendly or are inaccurate or are not validated for this application. A new sampler has recently been developed to address the user-friendliness issues with other samplers: the ASSET EZ4-NCO, but the use of this sampler in spray foam insulation applications has not been demonstrated or validated. Because of this, the current work was undertaken to provide a comparison of the ASSET sampler with an impinger method, considered to be the best available method in the context …

Candy Flavorings In Tobacco, Jessica E. Brown, Wentai Luo, Lorne M. Isabelle, James F. Pankow

Chemistry Faculty Publications and Presentations

Professor James F. Pankow reveals striking similarities between the patterns in the flavoring chemicals used in flavored tobacco products and those in popular candy and Kool-Aid products. The authors analyzed 12 artificially flavored candy and fruit drink products and compared them to 15 widely-available flavored tobacco products. They found significant overlap in the chemical signatures of the flavor chemicals. Several of the tobacco products contained flavor chemicals at much higher concentrations than in the non-tobacco products.

The Development Of Liquid Chromatography Mass Spectrometry Methods For The Analysis Of Cyanobacterial Toxins In Environmental Freshwaters, Brian Anthony Dineen

Theses

Cyanobacteria, also known as blue-green algae, are a common component of many freshwater and marine ecosystems and have a potential to produce several different classes of biotoxins. The most common class of cyanobacterial toxins are the microcystins (MCs) and cylindrospermopsins (CYLs). MCs are cyclic heptapeptides that display potent hepatotoxicity and are tumour promoters. CYLs are alkaloids that are cytotoxic and can cause illness and display hepatotoxic effects in animals and humans. Worldwide, these toxins have caused fatal poisonings to animals, birds and fish. Several incidents of human intoxications have been reported and the presence of these toxins in environmental waters …

Concern-Driven Integrated Toxicity Testing Strategies For Nanomaterials - Report Of The Nanosafety Cluster Working Group 10, Hugh Byrne, Agnes G. Oomen, Peter M.J. Bos, Teresa F. Fernandes, Kerstin Hund-Rinke, Diana Boraschi, Karin Aschberger, Stefania Gottardo, Frank Von Der Kammer, Dana Kühnel, Danail Hristozov, Antonio Marcomini, Lucia Migliore

Articles

Bringing together topic-related European Union-(EU)-funded projects, the so-called “NanoSafety Cluster” aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e. specific information needs for a given NM based on realistic exposure scenarios. Recognized concerns can be addressed in a set of tiers using standardized protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g. structure …

Investigation Of Pyrrolizidine Alkaloids In Foods Using Liquid Chromatography Mass Spectrometry, Caroline Griffin

Theses

Pyrrolizidine Alkaloids (PAs) are known plant toxins which can cause hepatic veno-occlusive disease (HVOD) in both humans and livestock when ingested. Although PAs are primarily known for their hepatotoxicity they also induce genotoxicity, carcinogenicity and pneumotoxicity. PAs are consumed through plants as food, for medicinal purposes, or as contaminants of agricultural crops. Aside from ingesting the plants directly PA exposure may occur through the consumption of honey produced by bees that visit PA-containing plants or by drinking milk produced by animals that have consumed PA-containing plants. Possible PA contamination in our food chain is a potential health risk.

To assess …

Impact Of Zinc Oxide Nanoparticles On Green Pea Plant & Seed Quality And Effects On Physiological Traits Of Green Peas, Corn, And Zucchini By Silver Nanoparticles, Arnab Mukherjee

Open Access Theses & Dissertations

The production and use of numerous engineered nanomaterials (ENMs) have increased exponentially over the past decade. Nanoparticles (NPs), ENMs possessing diameter between 1-100 nm, (NPs), are widely used in many applications. Worldwide consumption of NPs has increased their possible release into the environment. This, in turn, has elevated the extent of the potential impacts of NP exposure to living and non-living organisms. This is why the assessment of the impact of NPs on different environmental components, especially on plants, the producer in the food web, has become a very important aspect of nano-ecotoxicology. However, studies focusing on phytotoxicity and effects …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Immunological And Reproductive Health Assessment In Herring Gulls And Black-Crowned Night Herons In The Hudson-Raritan Estuary, Keith A. Grasman, Kathy R. Echols, Thomas M. May, Paul H. Peterman

University Faculty Publications and Creative Works

Previous studies have shown inexplicable declines in breeding waterbirds within western New York/New Jersey Harbor between 1996 and 2002 and elevated polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls (PCBs) in double-crested cormorant (Phalacrocorax auritus) eggs. The present study assessed associations between immune function, prefledgling survival, and selected organochlorine compounds and metals in herring gulls (Larus argentatus) and black-crowned night herons (Nycticorax nycticorax) in lower New York Harbor during 2003. In pipping gull embryos, lymphoid cells were counted in the thymus and bursa of Fabricius (sites of T and B lymphocyte maturation, respectively). The phytohemagglutinin (PHA) skin response assessed T cell function in …

Novel Liquid Chromatography - Fourier Transform Mass Spectrometry (Ms) And Triple Quadrupole Ms Methods For The Determination Of Diarrhetic Shellfish Poisoning (Dsp) Toxins., Bébhine Carey

Theses

Harmful algal blooms (HABs) appear to be on the rise globally, which not only has a negative impact on the shellfish industry but can also cause human and animal intoxications. In order to advance our knowledge of HABs, specific and sensitive analytical methods are required to aid in monitoring shellfish and algal samples for biotoxins, harmful to consumers.

Study Of Charge-Dependent Transport And Toxicity Of Peptide-Functionalized Silver Nanoparticles Using Zebrafish Embryos And Single Nanoparticle Plasmonic Spectroscopy, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Nanomaterials possess unusually high surface area-to-volume ratios and surface-determined physicochemical properties. It is essential to understand their surface-dependent toxicity in order to rationally design biocompatible nanomaterials for a wide variety of applications. In this study, we have functionalized the surfaces of silver nanoparticles (Ag NPs, 11.7 ±+2.7 nm in diameter) with three biocompatible peptides (CALNNK, CALNNS, CALNNE) to prepare positively (Ag-CALNNK NPs^+ζ), negatively (Ag-CALNNS NPs^−2ζ), and more negatively charged NPs (Ag-CALNNE NPs^−4ζ), respectively. Each peptide differs in a single amino acid at its C-terminus, which minimizes the effects of peptide sequences and serves as …

Lipid Peroxides And Glutathione Status In Human Progenitor Mononuclear (U937) Cells Following Exposure To Low Doses Of Nickel And Copper, William Y. Boadi, Shalandus Harris, Justin B. Anderson, Samuel E. Adunyah

Chemistry Faculty Research

Effects of Cu2+, Ni2+ or Cu2+ + Ni2+ on lipid peroxide and glutathione (GSH) levels in U937 cells were investigated. Cells were treated with 0, 5, 10, and 20 µM of Cu2+ and/or Ni2+ and H2O2 (0.01 mM) and incubated for 24 hours at 37°C. Lipid peroxides were measured by the thiobarbituric acid assay (TBA). GSH intracellular levels were assayed by the GSH assay kit from EMD/Calbiochem (San Diego, California, USA). Cu2+ or Ni2+ significantly (P < 0.01) increased lipid peroxides in a dose-dependent manner, compared to controls. The effect was more pronounced for Cu2+, compared to the Ni2+-treated samples. Cu2+ + Ni2+ increased lipid peroxides in a significant (P < 0.001), dose-dependent manner, compared to Cu2+ or Ni2+ alone (i.e., ratio of 2.5:1-fold for combined versus single treatments, respectively). Cu2+ or Ni2+ significantly decreased GSH levels in U937 cells, with the effect being pronounced for Cu2+. Cu2+ + Ni2+ metal ions significantly (P < 0.001) depleted cells of GSH in a dose-dependent manner. Ethylene diamine tetraacetic acid (EDTA) at 50 or 100 µM moderately reduced the Cu2+- or Ni2+-induced effects on GSH levels. Interestingly, GSH levels generally decreased to half (except for the combined metal dose of 20 µM at 100 µM EDTA) of its level at the highest metal concentration tested for both the single or combined treatments. In conclusion, multiple exposures of cells to metal ions may be lethal to cells, compared to their single treatments.

Arsenic Contamination In Groundwater In Vietnam: An Overview And Analysis Of The Historical, Cultural, Economic, And Political Parameters In The Success Of Various Mitigation Options, Thuy M. Ly

Pomona Senior Theses

Although arsenic is naturally present in the environment, 99% of human exposure to arsenic is through ingestion. Throughout history, arsenic is known as “the king of poisons”; it is mutagenic, carcinogenic, and teratogenic. Even in smaller concentrations, it accumulates in the body and takes decades before any physical symptoms of arsenic poisoning shows. According to the World Health Organization (WHO), the safe concentration of arsenic in drinking water is 10 µg/L. However, this limit is often times ignored until it is decades too late and people begin showing symptoms of having been poisoned.

This is the current situation for Vietnam, …

Investigations Of Oxidative Stress Effects And Their Mechanisms In Rat Brain After Systemic Administration Of Ceria Engineered Nanomaterials, Sarita S. Hardas

Theses and Dissertations--Chemistry

Advancing applications of engineered nanomaterials (ENM) in various fields create the opportunity for intended (e.g. drug and gene delivery) or unintended (e.g. occupational and environmental) exposure to ENM. However, the knowledge of ENM-toxicity is lagging behind their application development. Understanding the ENM hazard can help us to avoid potential human health problems associated with ENM applications as well as to increase their public acceptance. Ceria (cerium [Ce] oxide) ENM have many current and potential commercial applications. Beyond the traditional use of ceria as an abrasive, the scope of ceria ENM applications now extends into fuel cell manufacturing, diesel fuel additives …

High Resolution Hybrid Mass Spectrometry For The Determination Of Marine Biotoxins, Azaspiracids, And Their Biotransformation Products., Zuzana Skrabakova

Theses

Azaspiracids (AZAs), polyether marine toxins, are produced by marine microalgae and accumulate in filter-feeding bivalve molluscs, such as mussels, clams, oysters and scallops, while grazing on phytoplankton, from which they derive nutrition. Although being discovered quite recently, AZAs have caused several human intoxication events and thus became a problem for health authorities and shellfish industries. The rapid development of highly sensitive liquid chromatography multiple tandem mass spectrometry (LC-MS/MS, LC-MS") methods enabled the identification of numerous AZA analogues and added to the control of shellfish contamination. Tandem mass spectrometry techniques, while being highly selective and sensitive for determination of AZAs in …

Arsenic Speciation Analysis Of Biological Fluids : A Study Of Liquid Chromatography Coupled To Analytical Atomic Spectrometric Instrumentation, Kanna Ito

Legacy Theses & Dissertations (2009 - 2024)

Arsenic exists as many different chemical forms including inorganic, methylated and dietary species. The toxicity of these species varies: some are highly toxic and can cause adverse health effects in many parts of the body; others are considered relatively non-toxic. Monitoring arsenic exposure is usually accomplished by its direct measurement in biological fluids. Urine is the specimen of choice for assessing arsenic exposure, because of its short biological half-life in blood. There have been very few studies of arsenic species in blood, yet such research can provide valuable information on arsenic distribution and its metabolism in the body.

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 …

Landholder Information For The Safe Use And Management Of Strychnine For Wild Dog Traps, Renee Donovan, David Goodall

Biosecurity published reports

Farmnote 33/2003 - Guide to the safe use of strychnine for jawed traps is included.

Strychnine is a highly poisonous substance that is used in Western Australia for the control of Wild Dogs and Emus. Its use is restricted by law.

This manual outlines your roles and responsibilities for using and managing Strychnine for Wild Dog control. In particular, this manual outlines the essential information you need to know in regard to:

• The legislative requirements for Strychnine control in Western Australia
• The properties and mode of action of Strychnine « How to lodge an application to use Strychnine
• How to …

Landholder Information For The Safe Use And Management Of 1080, Renee Donovan, David Goodall

Biosecurity published reports

This manual outlines your roles and responsibilities for using and managing 1080. In particular this manual outlines the essential information you need to know in regard to:

• The legislative requirements for 1080 control in Western Australia
• The properties and mode of action of 1080
• How to lodge an application to lay 1080 baits How to safely store and transport 1080
• The procedures and notification required to carry out a baiting proposal
• Personal safety, identifying signs of poisoning & effecting appropriate first aid treatment
• Your responsibilities for notifying DAFWA and the Police of any accidents or incidents
• Methods for evaluating the …

Exploring Marine Biotoxins Using Analytical Techniques Based On Mass Spectrometry, Mónica Fernández Amandi

Theses

The impact of phycotoxins on human and animal health is of important concern for worldwide authorities and the scientific community. Domoic acid (DA) is a neurotoxin produced by phytoplankton {Pseudonitzchia spp.). It enters the food chain through the consumption of shellfish that feed on toxic diatoms. DA has been responsible for several outbreaks affecting humans and animals all around the world. Yessotoxin (YTX) is produced by dinoflagellate species {Protoceratiuni reticulatum) which are globally distributed. Its toxicity is low when ingested orally. However, the co-extraction of YTX with diarrhetic shellfish poisoning (DSP) toxins, derives false positives when the mouse bioassay is …

Analysis Of Phycotoxin And Mycotoxin, Contaminants In Foods, Using Liquid Chromatography - Mass Spectrometry Techniques, Ana Brana Magdalena

Theses

The impact of phycotoxins and mycotoxins on human and animal health are of important concern for worldwide authorities and the scientific community. Liquid chromatography-mass spectrometry (LC-MS) techniques have been developed, optimised and validated for the analysis of these toxins.

Phycotoxins are potentially toxic substances, which are produced by marine phytoplankton and which may accumulate in shellfish or finfish. Azaspiracid poisoning (AZP) is a recently discovered syndrome that has been implicated in several incidents of human intoxications. A study was undertaken to examine the distribution of azaspiracids (AZA) in scallops {Pecten maximiis) and mussels {Mytiliis edulis). Domoic acid (DA) is an …

1080 Summary Information, Department Of Agriculture, Western Australia, Department Of Conservation And Land Management, Western Australia, Department Of Health, Western Australia

Biosecurity research reports

Fluoroacetate, the active ingredient of 1080, occurs naturally in toxic plants in Australia, South Africa, and South America. Manufactured I080 underpins most vertebrate pest control programs in Australia and New Zealand. Fluoroacetate occurs naturally in about 40 plant species in Australia with most of these plants restricted to the south-west of WA.

I080 was introduced to rabbit control programs in the early 1950s and therefore has a long history of proven effectiveness and safety in Australia. There have been few repo1ted problems associated with human safety, environmental persistence, bioaccumulation or impact on populations of non-target species.

In particular, I080 baits …

Heavy Metals And Organic Pollutants In Sediments Of Dar Es Salaam Harbour Prior To Dredging In 1999, J F Machiwa

Tanzania Journal of Science

Heavy metals and organic contaminants were analysed in the sediments of the inner area of the Dar es Salaam harbour. Complementary analytical parameters, such as, the organic carbon content and the silt/clay fraction of the sediments showed good positive correlation (r = 0.64). Stations that had high content of fine grain material in the sediment also indicated relatively high level of organic carbon and pollutants. The Florida criteria (MacDonald 1993) for assessment of pollution of tropical marine sediments was adopted in oredr to evaluate the extent of pollution in Dar es Salaam harbour sediments. The Florida criteria is one of …

New Polyether Toxins From Shellfish And Marine Phytoplankton: Isolation Studies And Development Of Analytical Methods, Alan G. Bishop

Theses

There are three classes of polyether toxins responsible for Diarrhetic Shellfish Poisoning (DSP) world-wide. The causative toxins are okadaic acid (OA) and derivatives (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). The origin of these toxins are phytoplankton from Dinophysis or Prorocentrum spp. OA has been demonstrated for most outbreaks in Europe and more recently a new isomer DTX-2 has been reported in Ireland.

Marine phytoplankton biomass samples consisting predominantly of Dinophysis acuta, were acquired using a large double plankton net from waters off the South-west coast of Ireland. Analysis of unialgal samples using high performance liquid chromatography (HPLC) with fluorescence and …

Comparison Of Positive Screening And Confimatory Results From Federally Mandated Drug Testing Of Urine, Mary M. Stuck

Community & Environmental Health Theses & Dissertations

The purpose of this study was to analyze the accuracy of FDA approved immunoassays for the detection of drug positive urine samples.

Federal civilian employees are tested under the strict protocol of the Department of Health and Human Services mandatory guidelines for federal workplace drug testing programs. The guidelines provide for a two instrument testing protocol for the analysis of urine samples. The first is an FDA approved immunoassay. Samples which test positive on this screening immunoassay are then submitted for confirmatory testing with the "gold standard" gas chromatography/mass spectrometry.

Agency monthly drug testing summaries, required under the DHHS guidelines …