Pharmacology, Toxicology and Environmental Health Commons^™

Effects Of Respiratory Perturbations On Aging And Healthspan In Daphnia Magna, Millicent Nkiruka Ekwudo

Electronic Theses and Dissertations

Aging is a degenerative process characterized by a decline in physiological functions and cellular activities. Environmental and pharmacological interventions affecting longevity pathways have been extensively studied in model organisms. This study investigated the effect of chronic mild intermittent hypoxia (4 mg O2/L) or mild mitochondrial uncoupling with three doses of 0 (control), 0.1, 1, and 5 μM of 2,4-Dinitrophenol (DNP), on life history and gene expression in four clones of Daphnia magna. Interestingly, clones from intermittent ponds displayed better tolerance to hypoxia and DNP. Although neither treatments extended longevity, hypoxia increased fecundity and body size, and decreased food consumption and …

Negative Effects Of Common Herbicides On Non-Target Invertebrates, Debbi Albanese

Electronic Theses and Dissertations

Three herbicide formulations, Roundup® Ready to Use Weed and Grass Killer, Bayer Advanced Southern Weed Killer for Lawns and Pure 20% Vinegar Solution were directly applied to eggs of four species of butterflies, Danaus plexippus, Papilio cresphontes, Papilio polyxenes and Papilio troilus. Roundup and Bayer Advanced containing 2,4-D, mecoprop-p and dicamba significantly reduced hatch success in all four species. Lethal and sublethal effects of these herbicides on the earthworm, Eisenia andrei, was also examined. Direct contact by E. andrei with a heavy dose of the herbicides applied to tops of soil 24 hours prior was lethal to earthworms. …

Evaluating The Toxicity And Formation Of Halobenzoquinones In Point-Of-Use Chlorinated Drinking Water, Stephanie Hung

Masters Theses

Chlorine has effectively reduced the prevalence of waterborne diseases, however there are secondary consequences to this public health advancement. Disinfection byproducts (DBPs) are chemicals formed when chlorine reacts with natural organic matter (NOM) in water. A new class of DBPs, halobenzoquinones (HBQs), has recently been identified and data suggests it could be potentially carcinogenic and up to 1000 times more toxic than some regulated DBPs. So far, in vitro studies have assessed HBQ toxicity without taking into account its transformation in cell media into potentially less toxic compounds. This study evaluated the toxic effects of one HBQ, 2,6-DCBQ, and its …

Immunoregulation Of Liver Regeneration By The Aryl Hydrocarbon Receptor: Role Of Lymphocytes And Interferon-Gamma, Christopher John Horras

Boise State University Theses and Dissertations

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that elicits toxicity by activating the aryl hydrocarbon receptor. The toxic effects associated with TCDD exposure include immunotoxicity and dysregulated cell cycle control, although the mechanisms are poorly understood. A previous report indicates that exposure to TCDD suppresses hepatocyte proliferation in a mouse model of liver regeneration induced by 70% partial hepatectomy (PH). Based on reports that liver regeneration is negatively regulated by interferon (IFN)-γ produced by activated natural killer (NK) cells, along with the well-established immunotoxic effects of TCDD in other model systems, we hypothesized that TCDD treatment attenuates liver …

Influence Of 2,5-Hexanedione, Acrylamide, Tri-O-Tolyl Phosphate, Leptophos And Methylmercury On Endogenous Levels Of Tryptophan, Serotonin And 5-Hydroxyindoleacetic Acid And Serotonin Turnover Rates In Rat Brain, Craig H. Farr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several industrial and environmental chemicals cause distal and/or central neuropathy among other diverse toxic effects. Spague-Dawley derived rats were fed doses of 2,5-hexanedione, acrylamide, tri-o-tolyl phosphate, Leptophos and methylmercury via gavage. The dose levels and administration periods were established in previous experiments designed to assess clinical neuropathy using rats trained to walk on a rotorod apparatus fitted with an electrode floor. After intravenous injections of ³H-Tryptophan, whole rat brain homogenates were analyzed using liquid scintillation and spectrofluorometric techniques for levels of tryptophan, serotonin and 5-hydroxyindoleacetic acid. Serotonin turnover rates were calculated using the specific activities of tryptophan and serotonin …

Alterations In Rat Brain Norepinephrine And Dopamine Levels And Synthesis Rates In Response To Five Neurotoxic Chemicals: Acrylamide, 2,5-Hexanedione, Tri-O-Tolyl Phosphate, Leptophos, And Methyl Mercuric Chloride, Charles N. Aldous

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Acrylamide, 2,5-hexanedione, Tri-o-tolyl phosphate and leptophos belong to three fundamentally different chemical classes but all four chemicals cause central-peripheral distal axonopathy. Some of these compounds have been shown to alter brain steady state levels of neurotransmitters or to inhibit the activities of adenosine triphosphatases which are involved in the uptake and storage of biogenic amines. Tests were performed to determine alterations in steady state levels of rat brain norepinephrine and dopamine in response to doses of the above chemicals and of the central nervous system toxin, methyl mercuric chloride sufficient to cause ataxia. Catecholamine synthesis rate constant estimations were performed. …

Pesticide Exposure Studies: Direct And Indirect Detection Of Absorption Of 2,4-D And Pronamide Herbicides In The Guinea Pig And Occupationally Exposed Workers, Ibrahim A.R. Al-Jabery

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A simple high pressure liquid chromatography procedure was used to determine 2,4-D and pronamide exposure in spraymen and their dermal absorption and excretion in guinea pigs.

Results of dermal application of these herbicides to guinea pigs demonstrated a strong correlation between the applied dermal dose and the urinary residue excretion over the dosage range tested. As the dosage was increased, the urinary excretion of residues was also increased. However, the excretion of 2,4-D amine mixture following dermal treatment of guinea pigs was prolonged as compared to that of pronamide.

Residue levels of these compounds were also determined to estimate skin …