Toxicology Commons^™

Evaluation Of A Rapid-Screening Toxicity Test Using The Ciliate, Colpoda Inflata (Stokes): Sensitivity And Bioavailability To Model Compounds, Daria Galina Mochan

Dissertations and Theses

Standard toxicity tests often require high costs for maintaining healthy cultures, so few test species are employed in routine ecotoxicological analysis. An alternative is the "battery of tests" approach involving using rapid toxicity tests for screening. Rapid-screening toxicity tests must display organism sensitivity, similarity in responses to other test organisms, relevancy to many circumstances, and repeatability. Protozoa are ideal candidates for rapid-screening bioassays. They are cosmopolitan, play important roles in ecosystems, and have high reproductive rates. Many protozoa can form a resting stage (cyst) that remains viable during adverse conditions, eliminating the need for maintaining continuous cultures for testing.

The …

Lead Activation Of A Developmentally Regulated Calcium Channel In Rat Hippocampal Nerve Terminals, Troy E. Rhodes

Theses and Dissertations in Biomedical Sciences

Low level lead (Pb²⁺) exposure may produce lasting deficits in learning and memory by altering calcium (Ca²⁺) dependent processes. Isolated presynaptic nerve terminals from rat hippocampus were loaded with the intracellular (Ca²⁺) indicator Fura-2. The changes in cytoplasmic free calcium ([Ca²⁺]_i) were measured by stopped-flow fluorescence spectroscopy following depolarization with elevated potassium on a millisecond time scale (Lentzner et al., 1992). Depolarization promoted a rapid increase in Ca²⁺_i which occured in two kinetically distinguishable phases: a fast component, representing the activity of rapidly inactivating Ca²⁺ channels (τ …

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 …

Influence Of Soil On Bioremediation Potential Of Phanerochaete Chrysosporium, Brian J. Tucker

Biology

Successful bioremediation in soils using Phanerochaete chrysosporium is determined by many soil factors. Several biotic and abiotic soil factors inhibited P. chrysosporium in the mineralization of pyrene when compared to a non-soil system. Inhibition of pyrene mineralization was also observed with layers of sterilized silt and clay but not sand. Two clays, bentonite and kaolinite, differentially sorbed and decreased the mineralization of pyrene. Four artificial sterile, nonorganic soils, made with different proportions of sand, silt, and clay, inhibited pyrene mineralization by P. chrysosporium. Both purified humic acid and manganese oxide significantly reduced the mineralization potential of P. chrysosporium. …

Alteration In Basic Macrophage And Lymphocyte Cytokines From Benzene And Phenol In The Drinking Water Of Male Institute Of Cancer Research Mice, Jay C. Albretsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Groundwater contamination is a concern due to the large number of people that can become exposed to the contaminant. The chemicals benzene and phenol are known groundwater contaminants. The main health problem caused by benzene or phenol is bone marrow toxicity. Benzene and phenol are also immunotoxins reported to cause decreased thymic weights, altered lymphocyte mitogenic responses, and lower antibody production.

Cytokines are key signaling molecules produced by the cells of the immune system to activate other cells in the immune system, produce antibodies, and recruit other cells to sites of inflammation. The purpose of this study was to determine …

The Evaluation Of Succinylcholine Chloride For Harmful Effects Upon Early-Stage Mouse Embryos, Francis Warren Prescott

Biological Sciences Theses & Dissertations

Succinylcholine (SCh) chloride is a depolarizing neuromuscular blocking agent used to paralyze patients for surgical procedures. Over 1,800 clinical observations of newborn infants have demonstrated that succinylcholine does not cross the placenta in quantities detrimental to fetuses (Kolstad, et al., 1957, Bakhoum, et al., 1957, Hodges, et al., 1959, Duffield, et al., 1958, Dennis, et al., 1954, 1956, McNab, 1955, Coleman, et al., 1956, Lund, 1953). Later investigations which involved comparison of blood levels of SCh in the mother to those in fetuses bolstered the finding that SCh fails to cross the placenta in significant amounts (Moya and Kvisselgaard, 1961, …

Acidic Marine Biotoxins Implicated In Diarrhetic Shellfish Poisoning, Eoin P. Carmody

Theses

An okadaic acid (OA) etiology has been demonstrated for most outbreaks of diarrhetic shellfish poisoning (DSP) in Europe, An isomer of OA, dinophysistoxin-2 (DTX-2), has recently been found in Irish waters and, in 1991 and 1994, was the major toxin during prolonged infestations in cultivated mussels (Mytilus edulis) along the south-west coast of Ireland.

The OA class of DSP toxins have been analysed by HPLC using modified versions of three established fluorescent derivatisation methods. A ‘dual tag’ method for the confirmation of specific toxins has also been developed.

Survey work has been carried out over the past four years on …

Toxin Producing Phytoplankton In Chesapeake Bay, Harold G. Marshall

Biological Sciences Faculty Publications

Three diatoms and nine dinoflagellates, known to be associated with toxin production, have been identified within Chesapeake Bay. Over the past several decades this number has increased to its present level so that they now represent approximately 1.7% the total number of phytoplankton species reported for the Bay.