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NSAID effect on prostanoids in fishes: Prostaglandin E2 levels in bluntnose minnows (Pimephales notatus) exposed to ibuprofen.

Description: Prostanoids are oxygenated derivatives of arachidonic acid with a wide range of physiological effects in vertebrates including modulation of inflammation and innate immune responses. Nonsteroidal anti-inflammatory drugs (NSAIDs) act through inhibition of cyclooxygenase (COX) conversion of arachidonic acid to prostanoids. In order to better understand the potential of environmental NSAIDS for interruption of normal levels COX products in fishes, we developed an LC/MS/MS-based approach for tissu… more
Date: August 2009
Creator: Bhandari, Khageshor
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of cryopreservation methods for adherent nerve cell networks in vitro.

Description: Cryopreservation in suspension is commonplace for a variety of cell types. However, cryopreservation of adherent cells has achieved limited success. This research aimed to cryopreserve adherent nerve cell networks in vitro in a manner that preserved network morphology and physiology. Successful implementation would enable long term storage of adherent neuronal networks on microelectrode arrays and on-demand access for use in pharmacological and toxicological testing. Based upon morphological as… more
Date: December 2009
Creator: Webb, Veronica Fine
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Metabolic, cardiac and ventilatory regulation in early larvae of the South African clawed frog, Xenopus laevis.

Description: Early development of O2 chemoreception and hypoxic responses under normoxic (150 mmHg) and chronically hypoxic (110 mmHg) conditions were investigated in Xenopus laevis from hatching to 3 weeks post fertilization. Development, growth, O2 consumption, ventilatory and cardiac performance, and branchial neuroepithelial cells (NEC) density and size were determined. At 3 days post fertilization (dpf), larvae started gill ventilation at a rate of 28 ± 4 beats/min and showed increased frequency to 6… more
Date: December 2009
Creator: Pan, Tien-Chien
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Effects of Suspended Multi-Walled Carbon Nanotubes on Daphnid Growth and Reproduction

Description: Multi-walled carbon nanotube aggregates can be suspended in the aqueous phase by natural organic matter. These aggregates are ingested by filter feeding zooplankton. Ingested aggregates result in decreased growth and decreased reproduction. These effects may be caused by reduction in energy input from normal feeding behavior. pH alters natural organic matter structure through changes in electrostatic repulsion. Altered natural organic matter structure changes multi-walled carbon nanotube aggreg… more
Date: May 2010
Creator: Alloy, Matthew Michael
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Functional Neural Toxicity and Endocrine Responses in Mice Following Naphthalene Exposure

Description: Polycyclic aromatic hydrocarbons (PAHs) are a well studied and diverse class of environmental toxicants. PAHs act via the aryl hydrocarbon receptor (AhR), and studies have suggested that PAHs may elicit neurological and estrogenic effects. Doses of PAHs between 50 to 150 ppm may elicit neurotoxicity in rodent models. The present study investigated the effects of naphthalene on in vivo steroidogenesis in Swiss Webster male mice, and in vitro neural function of Balb-C/ICR mice frontal cortex ne… more
Date: August 2010
Creator: Colbert, Crystal
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Influence of in Vitro Gill and Liver Metabolism of Xenobiotics on Fish Bioconcentration

Description: This dissertation examines the ability of in vitro biotransformation assays to provide an indication of metabolic potential. The potential for xenobiotic compounds to bioconcentrate in aquatic organisms is expressed through the bioconcentration factor (BCF). The metabolic loss of ibuprofen, norethindrone and propranolol was measured using rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) gill and liver S9 fractions, microsomes and cell suspensions. Metabolic trans… more
Date: August 2010
Creator: Gomez, Cristi Frasier
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Determination of Bioconcentration Potential of Selected Pharmaceuticals in Fathead Minnow, Pimephales promelas, and Channel Catfish, Ictalurus punctatus

Description: The primary objective of this work was to determine the tissue-specific bioconcentration factors (BCFs) of the selected pharmaceuticals: norethindrone (NET), ibuprofen (IBU), verapamil (VER), clozapine (CLZ) and fenofibrate (FFB) in two freshwater fishes: fathead minnow and channel catfish. BCF tests on fathead followed the standard OECD 42-day test while a 14-day abridged test design was used in catfish exposures. Additional objectives included a) comparing the measured BCFs to the US EPA's BC… more
Date: December 2010
Creator: Nallani, Gopinath C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Characterization of Triclocarban, Methyl- Triclosan, and Triclosan in Water, Sediment, and Corbicula Fluminea (Müller, 1774) Using Laboratory, in Situ, and Field Assessments

Description: In the last decade emerging contaminants research has intensified in a bid to answer questions about fate, transport, and effects as these chemicals as they get released into the environment. The chemicals of interest were the antimicrobials; triclocarban (TCC) and triclosan (TCS), and a metabolite of triclosan, methyl triclosan (MTCS). This research was designed to answer the question: what is the fate of these chemicals once they are released from the waste water treatment plant into receivin… more
Date: May 2011
Creator: Edziyie, Regina E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Reproductive and Growth Responses of the Fathead Minnow (Pimephales Promelas) and Japanese Medaka (Oryzias Latipes) to the Synthetic Progestin, Norethindrone

Description: A commonly prescribed contraceptive, the synthetic progestin norethindrone (NET) inhibits ovulation in humans. However, ecotoxicological data are lacking. Preliminary tests produced an LC50 for NET of > 1.0 mg/L (96-hour, fathead minnow (FHM) and medaka) and a NOEC of 242.0 µg/L, a LOEC of 485.0 µg/L (7-day, growth for FHM and medaka). Reproductive testing revealed a LOEC for fecundity of 24.1 ng/L (21 days, medaka). Further testing confirmed the LOEC of 24.1 ng/L while defining a NOEC of 4.7 n… more
Date: May 2011
Creator: Paulos, Peter M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Retinoic acid Treatment Affects Kidney Development and Osmoregulatory System in the Developing Chicken (Gallus Gallus)

Description: Development is a dynamic process characterized by critical periods in which organ systems are sensitive to changes in the surrounding environment. In the current study, critical windows of embryonic growth and kidney development were assessed in the embryonic chicken. All‐trans retinoic acid (tRA) influences not only organogenesis and cell proliferation, but also targets metanephric kidney nephrogenesis. Embryonic chickens were given a single injection of tRA on embryonic day 8. tRA decre… more
Date: May 2011
Creator: Alvine, Travis Douglas
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A Comparison of Mercury Localization, Speciation, and Histology in Multiple Fish Species From Caddo Lake, a Fresh Water Wetland

Description: This work explores the metabolism of mercury in liver and spleen tissue of fish from a methylmercury contaminated wetland. Wild-caught bass, catfish, bowfin and gar were collected. Macrophage centers, which are both reactive and primary germinal centers in various fish tissues, were hypothesized to be the cause of demethylation of methylmercury in fish tissue. Macrophage centers are differentially expressed in fish tissue based on phylogenetic lineage, and are found primarily in the livers of p… more
Date: May 2012
Creator: Smith, James Durward
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Modeling the Relationship Between Golden Algae Blooms in Lake Texoma, Usa, Versus Nearby Land Use and Other Physical Variables

Description: Pyrmnesium parvum, commonly known as golden algae, is an algal species that under certain circumstances releases toxins which can lead to fish kills and the death of other economically and ecologically important organisms. One of the major objectives of the study was to investigate whether a relationship exists between land use and Prymnesium parvum abundance in littoral sites of Lake Texoma, USA. Another objective was to investigate whether a relationship exists between other physical variable… more
Date: August 2012
Creator: Ware, Trudy M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Optimizing Scientific and Social Attributes of Pharmaceutical Take Back Programs to Improve Public and Environmental Health

Description: Research continues to show that pharmaceutical environmental contamination has caused adverse environmental effects, with one of the most studied effects being feminization of fish exposed to pharmaceutical endocrine disruptors. Additionally, there are also public health risks associated with pharmaceuticals because in-home reserves of medications provide opportunities for accidental poisoning and intentional medication abuse. Pharmaceutical take back programs have been seen as a remedy to th… more
Date: August 2012
Creator: Stoddard, Kati Ireland
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Proteomic Responses in the Gill of Zebrafish Following Exposure to Ibuprofen and Naproxen

Description: Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most abundant environmental pharmaceutical contaminants. In this study, a proteomic analysis was conducted to identify proteins differentially expressed in gill tissue of zebrafish (Danio rerio) after a 14-day exposure to the NSAIDs ibuprofen or naproxen. A total of 104 proteins with altered expression as indicated by 2-dimensional electrophoresis were analyzed by liquid chromatography with ion trap mass spectrometry (MS/MS). A total … more
Date: August 2012
Creator: Adhikari, Prem R.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus

Description: Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the… more
Date: December 2012
Creator: Rossitto Lopez, Josie Jovita
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Characterization of Arthrobacter Globiformis Aspartate Transcarbamylase Concentrations of Substrates

Description: This thesis consists of one major section with two subsections. The first subsection investigates the activity of Arthrobacter globiformis aspartate transcarbamylase's specific activity with increasing concentrations of the enzyme's substrate. Dihydroorotase (DHOase) activity was also measured with increasing concentrations of the substrate dihydroorotate. The second subsection collected data in order to classify the enzyme, resulting in a classification into the category of class A ATCases … more
Date: December 2012
Creator: Wright, Jackie
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Chronic Hypoxia and Hyperoxia Modifies Morphology and Vegf Expression of the Lungs of the Developing Chicken (Gallus Gallus Domesticus)

Description: This study determines effects of oxygen levels on morphology and VEGF expression of developing chicken lungs following incubation in normoxia (21% O2), hypoxia (15% O2) or hyperoxia (30% O2), until developmental days 16 or 18. Lung morphology was assessed using light microscopy, while VEGF expression was determined with ELISA. In hypoxia, the proportion of parabronchial tissue and parabronchi including lumina increased from day 16 to 18 (61 to 68% and 74.2 to 82.2%, respectively). Non-parabronc… more
Date: December 2012
Creator: Lewallen, Melissa Anjanette
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp

Description: Few studies have been conducted on the effectiveness of phytoremediation of pharmaceutical compounds, although the persistent and non-acutely toxic nature of many of these compounds in today's water bodies may yield an ideal application for this practice. To quantify the potential effectiveness of plant uptake, kinetic and proportional bioconcentration factors (BCFk, and BCFp, respectively) in nanograms (ng) carbamazepine and amiodarone per gram (g) wet weight plant tissue for Lemna spp. were d… more
Date: August 2013
Creator: Woodard, Jennifer Kristin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Development of Novel Semi-conducting Ortho-carborane Based Polymer Films: Enhanced Electronic and Chemical Properties

Description: A novel class of semi-conducting ortho-carborane (B10C2H12) based polymer films with enhanced electronic and chemical properties has been developed. The novel films are formed from electron-beam cross-linking of condensed B10C2H12 and B10C2H12 co-condensed with aromatic linking units (Y) (Y=1,4-diaminobenzene (DAB), benzene (BNZ) and pyridine (PY)) at 110 K. The bonding and electronic properties of the novel films were investigated using X-ray photoelectron spectroscopy (XPS), UV photoelectro… more
Date: August 2013
Creator: Pasquale, Frank L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Effects of Glyphosate Based Herbicides on Chick Embryo Development

Description: Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In thi… more
Date: August 2013
Creator: Winnick, Blake Edward
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Effects of Natural/anthropogenic Stressors and a Chemical Contaminant on Pre and Post Mycorrhizal Colonization in Wetland Plants

Description: Arbuscular mycorrhizal fungi, colonizing over 80% of all plants, were long thought absent in wetlands; however, recent studies have shown many wetland plants harbor arbuscular mycorrhizae (AM) and dark septate endophytes (DSE). Wetland services such as biodiversity, shoreline stabilization, water purification, flood control, etc. have been estimated to have a global value of $14.9 trillion. Recognition of these vital services is accompanied by growing concern for their vulnerability and continu… more
Date: August 2013
Creator: Twanabasu, Bishnu Ram
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Endocrine Disruption of Levonorgestrel in Early-life Stages of Fathead Minnows, Pimephales Promelas

Description: Pharmaceuticals have routinely been detected in the environment resulting in a growing concern about whether these drugs could elicit effects on aquatic organisms. The concerns are centered on the highly conserved nature of mammalian therapeutic targets in fish. These pharmaceuticals are found at very low levels in the environment, which can result in sub-lethal effects in aquatic organisms. Therefore, 28 d early-life stage studies were conducted on six pharmaceuticals to assess their impact… more
Date: August 2013
Creator: Overturf, Matthew D.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Tissue-specific Bioconcentration Factor of the Synthetic Steroid Hormone Medroxyprogesterone Acetate (Mpa) in the Common Carp, Cyprinus Carpia

Description: Due to the wide spread occurrence of medroxyprogesterone acetate (MPA), a pharmaceutical compound, in wastewater effluent and surface waters, the objectives of this work were to determine the tissue specific uptake and bioconcentration factor (BCF) for MPA in common carp. BCFs were experimentally determined for MPA in fish using a 14-day laboratory test whereby carp where exposed to 100 μg/L of MPA for a 7-day period followed by a depuration phase in which fish were maintained in dechlorinate… more
Date: August 2013
Creator: Steele IV, William B.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Effect of Menthol on Nicotine Metabolism: a Cross Species Evaluation

Description: The effect of menthol on nicotine metabolism was examined in liver S9 fractions of four different species and in the in vivo mouse model. The purpose of this study was to investigate three parameters: (1) biotransformation of nicotine to cotinine in various species (human, mouse, rat and trout) using in vitro methods; (2) to determine if the addition of menthol with nicotine altered biotransformation of nicotine to cotinine; (3) and to assess similar parameters in an in vivo mouse model. The… more
Date: December 2013
Creator: Pace, Wendy Lee
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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