Toxicology Commons^™

Effects Of 17Α-Ethinylestradiol (Ee2) On Reproductive Endocrine Status In Mummichog (Fundulus Heteroclitus) Under Differing Salinity And Temperature Conditions, Esteban Gillio Meina

Theses and Dissertations (Comprehensive)

Waterborne exposure to 17α-ethinylestradiol (EE₂), a synthetic estrogen, has previously been shown to decrease reproductive endocrine status in the estuarine killifish or mummichog (Fundulus heteroclitus macrolepidotus; northern subspecies). To evaluate if variations in salinity or temperature holding conditions modify the effects of EE₂ on gonad size, plasma reproductive steroid levels, and gonadal steroidogenesis, mummichog were exposed in vivo for 14 days to 0, 50 and 250 ng/L EE₂ in 0, 16 and 32 ppt salinity at 18°C and to 0 and 250 ng/L EE₂ at 10, 18 and 26°C at 16 ppt salinity. …

The Chronic Toxicity Of Titanium Dioxide Nanoparticles To The Freshwater Amphipod Hyalella Azteca, Gurkirpal S. Malhi

Theses and Dissertations (Comprehensive)

There has been an increased use of metal-oxide nanoparticles in both commercial and consumer products. The use of these products and waste generated during manufacture may ultimately be released into the aquatic environment and the potential for these contaminants to cause impacts must be assessed. This study examines the effect of titanium dioxide (TiO₂) nanoparticles (NPs) on Hyalella azteca. Chronic toxicity exposures were conducted in 400mL of spiked test solution and contained 20 neonates. Samples collected for characterization of Ti in TiO₂ NP exposure solutions were digested using ammonium persulfate as an oxidizing agent and dissolved …

Classification Of Plants According To Their Heavy Metal Content Around North Mara Gold Mine, Tanzania: Implication For Phytoremediation, N. Mganga, Mlk Manoko, Z. K. Rulangaranga

Tanzania Journal of Science

Plants like other living organisms respond differently under different environmental conditions. An elevated level of heavy metals is one of the stresses which results into three classes of plants depending on their heavy metal content. The classes of plant species according to their accumulated heavy metals around North Mara Gold Mine were not known. To study such classes, a line transect of 700m long was established opposite the gold mine wastes. A total of eight sampling points were systematically established each after every 100m in that transect. Fifteen plant species were sampled; at least one species per sampling point. Approximately …

Degradation Of Atrazine By White Rot And Soil Fungi, Gerald Presley

Undergraduate Honors Theses

The widespread use of atrazine in agriculture has lead to an abundance of this toxic chemical in the environment. Fungi that have the ability to degrade atrazine into less toxic products have been identified and used in the remediation of atrazine. In this study atrazine degradation in a defined liquid media was characterized in a diverse group of white rot basidiomycete and deuteromycete soil fungi. Atrazine did not have an effect on fungal growth although each species produced a different amount of biomass in culture. Statistical analysis showed that biomass production was an important factor in determining the amount of …

2012 Barley Variety Sowing Guide For Western Australia, Blakely Paynter, Andrea Hills, Harmohinder Dhammu

Bulletins 4000 -

This variety guide is designed as a quick reference to help growers determine which barley variety to grow in their region. It provides domestic and international market feedback, relative grain yield comparisons, disease ratings, agronomic information and herbicide tolerance ratings for all malting barley varieties, the new food variety and selected feed varieties.

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 …

Causes, Extent, And Consequences Of Lead-Pellet Ingestion By Chukars (Alectoris Chukar) In Western Utah: Examining Habitat, Search Images, And Toxicology, R. Justin Bingham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lead ingestion adversely affects humans and over 130 species of wildlife. Wild chukars (Alectoris chukar) are documented to ingest lead, but the causes and consequences of this ingestion are poorly understood. The objectives of this research were to 1) examine the influence of habitat use, the hunting season, and seasonal climate on the extent and severity of lead ingestion by chukars in western Utah, 2) assess the effects of habitat use, feeding behaviors, and lead density on the causes of lead-pellet ingestion in captive and wild chukars, and 3) investigate the consequences of lead-pellet ingestion in captive chukars as a …

Estrogen Sulfotransferase (Sult1e1) Expression And Function In Mcf10a-Series Breast Epithelial Cells: Role As A Modifier Of Breast Carcinogenesis And Regulation By Proliferation State, Jiaqi Fu

Wayne State University Dissertations

Estrogen sulfotransferase (SULT1E1) catalyzes the sulfonation of estrogens, which limits estrogen mitogenicity. TaqMan Gene Expression assays were used to profile the mRNA expression of estrogen receptor (ERα and ERβ) and estrogen metabolism enzymes including cytosolic sulfotransferases (SULT1E1, SULT1A1, SULT2A1, and SULT2B1), steroid sulfatase (STS), aromatase (CYP19), 17β-hydroxysteroid dehydrogenases (17βHSD1 and 2), CYP1B1, and catechol-O-methyltransferase (COMT) in an MCF10A-derived lineage cell culture model for basal-like human breast cancer progression and in ERα-positive luminal MCF7 breast cancer cells. Low levels of ERα and ERβ mRNA were present in MCF10A-derived cell lines. SULT1E1 mRNA was more abundant in confluent relative to subconfluent MCF10A …

Compensatory Renal Hypertrophy, Mitochondria And Redox Status, Bavneet Benipal

Wayne State University Dissertations

A reduction in functional renal mass occurs in humans during aging and severe kidney damage from diseases, injuries, infections and congenital conditions and after nephrectomy. Nephrectomy, or surgical removal of a kidney or a section of a kidney, is performed for treatment of unilateral secondary renal cancer, infections and for kidney transplantation. As a result, the remaining renal tissue undergoes compensatory growth due primarily to hypertrophy, in which both the size and functional capacity of the remaining kidney are increased. Renal compensatory hypertrophy is associated with a series of physiological, morphological and biochemical changes that also have toxicological implications.

Previous …

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 …

Gene And Environment Interactions Modulate Immune System Influences On Social Behavior, Yubin Zhang

Legacy Theses & Dissertations (2009 - 2024)

Autism is a neurodevelopmental disorder with unknown etiology, affecting about 1 in 110 children in the US. Here, we show that developmental exposure to anti-brain Abs impaired mouse social behaviors. BTBR mice, a mouse strain with high serum anti-brain Abs and behaviors that resemble autism, have more activated splenic B cells, CD4+ T cells (Th1, Th2 and Th17 subsets), and CD4+ T cells with expression of Vb6 chains than B6 mice (the control H-2 identical strain). Elevated numbers of activated (CD25+) CD4+Vb6+ cells also were detected in thymic preparations. All of the immunological and behavioral parameters of BTBR mice were …

The Nasal Toxicity Of The Herbicide 2,6-Dichlorobenzonitrile : Mechanisms And Biomarkers, Fang Xie

Legacy Theses & Dissertations (2009 - 2024)

The overall goal of this study is to investigate mechanisms of the potent nasal specific toxicity of the herbicide 2,6-dichlorobenzonitrile (DCBN) in rodents, and to determine whether DCBN could induce similar nasal toxicity in humans. The central hypotheses are 1) that the nasal specific toxicity of DCBN in rodents is mediated by its electrophilic intermediates that are formed through metabolic activation catalyzed by target tissue cytochrome P450 enzymes (P450) and can interfere with stem cell regeneration and differentiation in the olfactory epithelium (OE); and 2) that human nasal tissues are also capable of catalyzing bioactivation of DCBN. The specific aims …

Regulation Of The Aryl Hydrocarbon Receptor And The Signal Transducer And Activator Of Transcription 1 By Long-Term Estrogen Exposure In Breast Carcinoma Cells, Neal Englert

Legacy Theses & Dissertations (2009 - 2024)

The risk of developing breast cancer is known to be associated with a woman's lifetime exposure to estrogens, both endogenous and exogenous. Increased exposure to estrogens stimulates cellular proliferation, which is a widely accepted theory of estrogen receptor positive mammary carcinogenesis. The molecular mechanisms of gene expression regulation in response to long-term estrogen exposure (LTEE) of MCF-7 breast cancer cells were addressed in this study, with a focus on the aryl hydrocarbon receptor (AHR) and signal transducer and activator of transcription 1 (STAT1).

Genotoxin-Induced Acetylation Of The Werner Syndrome Protein (Wrn) And Effect On Its Dna Metabolic Function, Enerlyn Meliza Lozada Santiago

University of Kentucky Doctoral Dissertations

Loss of function of the WRN protein causes the genetic disorder Werner Syndrome that is characterized by increased cancer and premature aging. WRN belongs to the RecQ helicase family that plays key roles in preventing genome instability. In response to treatment with genotoxins, WRN is subject to post-translational modification. The relationship of post-translational modification of WRN with its function in DNA metabolism is unknown. There is accumulating evidence suggesting that WRN contributes to the maintenance of genomic integrity through its involvement in DNA replication. Consistent with this notion, WS cells are sensitive to DNA replication inhibitors and DNA damaging agents …

Identification Of Activities Involved In Cag/Ctg Repeat Instability, Nelson Lap Shun Chan

University of Kentucky Doctoral Dissertations

CAG/CTG repeat instability is associated with at least 14 neurological disorders, including Huntington’s disease and Myotonic dystrophy type 1. In vitro and in vivo studies have showed that CAG/CTG repeats form a stable hairpin that is believed to be the intermediate for repeat expansion and contraction.

Addition of extra DNA is essential for repeat expansion, so DNA synthesis is one of the keys for repeat expansion. In vivo studies reveal that 3’ CTG slippage with subsequent hairpin formation (henceforth called the 3’ CTG slippage hairpin) occurs during DNA synthesis. It is proposed that hairpin tolerance machinery is activated because prolonged …

Overuse Of Antibiotics In Children For Upper Respiratory Infections (Uris): A Dilemma, Malika Taufiq, Rukhsana Wamiq Zuberi

Department for Educational Development

No abstract provided.

Mycotoxins In Grains – Causes, Prevention And Control, Hester F. Vismer

INTSORMIL Presentations

Discusses mycotoxins, their effect on grain, mitigation considerations, and resulting human toxicology.

Pharmacokinetic Evaluation Of The Blood: Tissue Relationship In Poultry: Screening For Antibiotic Residues In Chicken Muscle, Ixchel Reyes Herrera

Graduate Theses and Dissertations

During their life, humans are exposed to numerous substances that are naturally present in the environment or that are the result of man made processes, including heavy metals, persistent organic pollutants, pesticides and veterinary drugs. Some of these substances can leave residues in food products and possibly expose consumers to their potential toxic effects. To address these problems extensive regulatory efforts are devoted to prevent, detect and control these substances from reaching the food supply. However, given the vast diversity of food products that requires monitoring and the immense diversity of potential chemical contaminants, the need for an efficient and …

Aluminium Phosphide Poisoning: A Case Report, Shela Akbar Ali Hirani, Arshalooz Rahman

School of Nursing & Midwifery

This paper reports the case of a family in which three children were presented at Emergency Room (ER) with poisoning after the use of a pesticide at home. Initially, the cases were managed as routine cases of organophosphorus poisoning; however, the death of two children made the health team members realise that the poison's effects were delayed and devastating. Later, the compound was identified as Aluminium Phosphide (ALP), and the life of the last surviving child in the family was saved.

Curated Exhibit: Absolute Poison, Laura J. Hall

Posters and Presentations

The Absolute Poison exhibit, curated by Laura J. Hall, MFA, delved into the fascinating and deadly world of poisons. From the ancient Sumerian goddess Gula, to Shakespeare’s Hamlet, and the infamous cyanide-laced Tylenol case of 1982, poisons have long held a place in our collective imagination. The exhibit explored the history, symbolism, and cultural impact of poisons, featuring materials such as Albrecht Dürer’s Adam and Eve with its skull and crossbones motif symbolizing death. On display from September 2010 to August 2011 at the UNM Domenici Center, the exhibit examined how poisons have shaped narratives of danger and mystery. September …