In this research a test system was developed that is designed as a tool to evaluate the potential hazard of chemicals to aquatic ecosystems. The system developed is a linear three-trophic level food chain consisting of an alga (Ch/ore/la vulgaris), rotifer (Brachionus calyciflorus), and fish (Pimephales promelas). The chemostat design used for the lower two trophic levels was crucial in being able to supply the top trophic level with sufficient food on a continuous basis. The system was initially evaluated using copper (Cu) and selenium (Se) as toxicants. In the copper experiments, results of a 7 day three-trophic level toxicity test were compared with a series of single species tests. The LOEC was 31.5 µg/L based on a temporary impairment of the algal population growth, with a corresponding NOEC of 16.2 µg/L. The algal population at all initially impaired treatment levels demonstrated recovery to control levels by the end of the test. Single species tests with the same species showed impairment at treatment concentrations lower than the corresponding value from the three-trophic level test. The difference in sensitivity is attributable to the fact that most of the Cu in the single species tests was in the dissolved form (approximately 80 %), whereas in the trophic level test most of the Cu was not ( < 15 % dissolved Cu). The three-trophic level Se experiment lasted for 25 days, with both short-term and long-term impacts evident. At the algal trophic level, growth was not impaired on a daily basis at any of the exposure levels (110.3, 207.7, and 396.1 µg/L Se). However, algal densities were slightly reduced at the 207. 7 and 396.1 µg Sell treatments, although not significantly different when the data was pooled across days. Rotifer populations were impaired at these same levels by day 4, and succumbed to the Se by day 7. Fathead minnow growth was also impaired at these two concentrations by day 7. In addition, sub lethal impairment of rotifer and fish growth was evident at the 110.3 pg/L level after day 20 indicating a more subtle trophic impact. Bioconcentration factors ranged between 100 and 1000 µg/L and were found to be dependent on the species, treatment, and day. / Ph. D.

The purpose of this research was to develop a test system for screening toxic substances by predicting their aquatic ecosystem effects. The system studied was a static, one liter microcosm with a diverse species assemblage. Teh microcosm was composed of biotic inoculum, chemically defined medium and sediment. The biotic inoculum cotained primary producers, grazers, carnivores and decomposers. The chemical medium used was Taub #82 modified by adding sodium bicarbonate. Three different types of sediment were studied: sand, clay and clay plus sand. Four organic chemicals: phenol, triethylene glycol (TEG), quinoline and naphtoquinone were evaluated with this test system. The toxicities of TEG, quinoline and naphthoquinone were compared for each sediment type. Toxicity was evluated in terms of the chemicals' effects on primary productivity and heterotrophic activity though other effects are also noted. The toxicity of the chemicals in this study was compared to those from other toxicological evaluations based on threshhold toxicity values (EC20 and LC50). The screening test sytem evaluated in this study did not demonstrate significanly different threshhold toxicity values than the other screening systems to which it was compared. The ranking of the toxicants based on EC20 values was different for the two ecosystem properties, net production and heterotrophic activity. Naphthoquinone concentration exhibited no correlation between ecosystems property values and therefore, could not be ranked. Phenol exhibited the greatest toxicity to net production immediately after the toxicant addition. Quinoline was most toxic to net production over the longer time scale. TEG exhibited the least toxicity to net production, however, TEG exhibited higher toxicity to heterotrophic activity than either quinoline or phenol. Although the type of sediment used in the nicrocosms did not change the relative toxicities of the chemicals, the microcosms with clay sediment always were observed to exhibit lower net production and higher variability. Nonparametric statistical analyses are recommended for microcosm studies because of the lack of normally distributed data. Confidence limits of 80% are recommended because of the need for biologically conservative estimates of ecosystem toxicity. / Ph. D. / incomplete_metadata

This study consisted of a site characterization followed by a biomonitoring study utilizing the zebra mussel, <i>Dreissena polymorpha</i>, at the Times Beach Confined Disposal Facility (CDF), located in Buffalo, New York. Concentrations of the selected contaminants (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and the following metals: arsenic (As), chromium (Cr), barium (Ba), mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se) and silver (Ag), were at or below detection limits in the water column. In the sediment toxicant concentrations were as high as 549 mg/kg for total PAHs, 9 mg/kg for PCB Aroclor 1248, and 54, 99, 6, 355, 637, and 16 mg/kg for the metals: As, Ba, Cd, Cr, Pb, and Hg respectively. To predict contaminant bioavailability, elutriate and whole sediment toxicity tests were performed utilizing the cladoceran, <i>Daphnia magna</i>. The whole sediment tests showed a significant impact. Control survival was 84%, while the sediment treatment survival range was 1-7%. Mean control reproduction was 86.8 neonates, whereas treatment group reproduction ranged from 1.4 to 9.0. Zebra mussels, placed both in the water column (Upper) and at the sediment level (Lower), survived the 34-day exposure. Contaminants which significantly accumulated in zebra mussel tissue during the exposure period (mg/kg) were total PAHs (6.58), fluoranthene (1.23), pyrene (1.08), chrysene (0.98), benzo(a)anthracene (0.60), PCB Aroclor 1248 (1.64), As (0.97), Cr (2.87), and Ba (7.00). The accumulation of benzo(a)anthracene was statistically higher in the Upper mussels; however, this did not occur for any other toxicant. Accumulation of these contaminants in zebra mussel tissue represent a potential hazard to organisms (ie. fish and birds) which feed on them. / Master of Science

Declining unionid populations in the Clinch River are of concern due to the high endemism in the diverse fauna of the Cumberlandian region. Increase in agricultural and mining activities, as well as in industry and urbanization, are coupled with unionid declines throughout the watershed. In many reaches of the Clinch River, mussel populations exist which fail to show recruitment suggesting that this is the weak link in the complex life cycle. Two possible factors which could endanger the sensitive juvenile stage are the presence of sediment toxicants or adult Corbicula fluminea in the depositional areas, the preferred habitat of the juveniles. Before investigating the impacts of these factors, it was necessary to characterize the relationship of the juveniles with the sediment they inhabit. Observations of feeding behavior using videotape, dye studies in a feeding chamber, and gut content analysis were used to determine mechanisms of feeding, the primary food source, and the origin of substances taken up by juveniles. Exposure to sediment came not only through direct contact, but also through filtration of interstitial water and sediment-associated fine particulate organic matter. Juveniles used pedal locomotory and pedal sweep feeding behaviors to facilitate movement of particles into the pedal gape. Intermittent sediment toxicity was found in laboratory bioassays using Daphna magna and Chironomus riparius. These data, along with fluctuating metals in the Clinch River sediments, indicated that acute insults existed from which recovery would depend on the frequency, intensity and duration of the events. Field studies revealed that the intermittent toxicity is reflected in the community structure of benthic macroinvertebrates and impairs growth of juvenile unionids in-situ studies. The intermittent toxicity which may be associated with rain events impairs stream biota and may prevent recruitment of juvenile unionids. The presence of adult C. fluminea in sediments was found to decrease juvenile unionid growth and recovery from test sediments and to increase mortality and resuspension of juveniles into the water column. Both the presence of sediment-bound toxicants and C. fluminea may be contributing to unionid bivalve declines in the Clinch River, Virginia. / Ph. D.

This study examined the effects of low to moderate doses of manganese (0, 250, or 750 _g per day from PD 1-21) on a comprehensive battery of behaviors in rats during the neonatal period, preweanling period, and in adulthood.

Previous studies have demonstrated that the feeding behaviour of Lumbriculus variegatus may be significantly inhibited during exposure to toxic substances. The potential use of an in situ sediment bioassay, using L.variegatus post-exposure feeding inhibition as an endpoint, was investigated. The bioassay consisted of exposing animals in the field for a six-day exposure period and feeding rates were measured immediately afterwards over a twenty-four hour post-exposure period. The bioassay methodology developed in the laboratory produced a consistent baseline response that was reliable and repeatable. Endpoint sensitivity was demonstrated under laboratory conditions, where bioassay organisms exhibited delayed recovery from feeding inhibition after previous exposure to sediment-associated contaminants. The apparent insensitivity of the bioassay to sediment-associated metals means that the technique should only be used as part of a suite of bioassays that employ representative deposit feeders. The ecological relevance of the bioassay endpoint was also demonstrated by comparing short-term measures of post-exposure feeding inhibition with the longer-term effects of a toxicant on L.variegatus populations. The bioassay methodology was successfully adapted for in situ use. Post-exposure feeding inhibition was detected at contaminated field sites. However, the consistent baseline response produced in the laboratory could not be replicated during deployments of the bioassay at upstream (“clean”) field sites. Increased environmental “noise” may have been a result of a number of confounding factors that could limit the sensitivity of the bioassay endpoint if not adequately controlled. Despite the above concerns, the in situ bioassay is suggested to represent a useful tool, which uses a more realistic field exposure scenario to investigate the effects of sediment-associated toxicants with an important functional component of aquatic ecosystems.

Copepods comprise an ecologically important role in freshwater and marine ecosystems, which is why they are often considered an important ecotoxicological model organism. The International Organization for Standardization’s (ISO) 14669 protocol is the only guideline for the determination of acute toxicity in three European marine copepod species: Acartia tonsa. The goal of this project was to assess the feasibility of establishing and maintaining cultures of Acartia tonsa, as well as to refine current culturing and egg separation methods. Initial culture methodology proved difficult for consistent production of eggs and collection of nauplii. The development of an airlift system for the separation of eggs from nauplii and adults, based on size, successfully increased the availability of eggs, nauplii and adults. The sensitivity and relative conditions of the copepod species was assessed by running a series of 48h acute toxicity tests with the reference toxicants 3,5-dichlorophenol, 4,4’-methylenebis(2,6-di-tert-butylphenol. The acute 48 hour median lethal dose concentration (LC50), the no observed effect concentration (NOEC), and the lowest observed effect concentration (LOEC) was analyzed for the three reference compounds for of A. tonsa.

by Wong Suk Ying. / Thesis submitted in: November 2001. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 144-157). / Text in English; abstracts in English and Chinese. / by Wong Suk Ying. / Acknowledgments --- p.i / Abstract --- p.ii / Contents --- p.v / List of Figures --- p.x / List of Tables --- p.xvi / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Electroplating Industry in Hong Kong --- p.1 / Chapter 1.1.1 --- Typical stages in electroplating process --- p.1 / Chapter 1.1.1.1 --- Pre-treatment --- p.1 / Chapter 1.1.1.2 --- Electroplating --- p.3 / Chapter 1.1.1.3 --- Post-treatment --- p.3 / Chapter 1.1.2 --- Typical characteristics of wastestreams from electroplating industry --- p.3 / Chapter 1.2 --- Chemical Specific Approach against Toxicity Based Approach --- p.6 / Chapter 1.3 --- Ecotoxicological Study on Electroplating Effluent --- p.7 / Chapter 1.4 --- Toxicity Identification Evaluation --- p.8 / Chapter 1.4.1 --- Phase I: Toxicity Characterization --- p.9 / Chapter 1.4.2 --- Phase II: Toxicity Identification --- p.10 / Chapter 1.4.3 --- Phase III: Toxicity Confirmation --- p.12 / Chapter 1.5 --- Toxicity Identification Evaluation on Electroplating Effluent --- p.14 / Chapter 1.6 --- Selection of Organisms for Bioassays --- p.15 / Chapter 1.6.1 --- Organism used for toxicity identification evaluation --- p.17 / Chapter 2. --- OBJECTIVES --- p.20 / Chapter 3. --- MATERIALS AND METHODS --- p.21 / Chapter 3.1 --- Source of Samples --- p.21 / Chapter 3.2 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity Test --- p.21 / Chapter 3.2.1 --- Microtox® test --- p.23 / Chapter 3.2.2 --- Growth inhibition test of a marine unicellular microalga Chlorella pyrenoidosa CU-2 --- p.25 / Chapter 3.2.3 --- Survival test of a marine amphipod Hylae crassicornis --- p.28 / Chapter 3.2.4 --- Survival test of a marine shrimp juvenile Metapenaeus ensis --- p.31 / Chapter 3.3 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.34 / Chapter 3.3.1 --- pH adjustment filtration test --- p.35 / Chapter 3.3.2 --- Aeration test --- p.36 / Chapter 3.3.3 --- C18 solid phase extraction test --- p.37 / Chapter 3.3.4 --- EDTA chelation test --- p.38 / Chapter 3.3.5 --- Graduated pH test --- p.40 / Chapter 3.4 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.41 / Chapter 3.4.1 --- Filter extraction test --- p.41 / Chapter 3.4.2 --- Total metal content analysis --- p.42 / Chapter 3.5 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.43 / Chapter 3.5.1 --- Chemicals --- p.44 / Chapter 3.5.2 --- Mass balance test --- p.44 / Chapter 3.5.3 --- Spiking test --- p.44 / Chapter 4. --- RESULTS --- p.46 / Chapter 4.1 --- Chemical Characteristics of the Electroplating Effluent Samples --- p.46 / Chapter 4.2 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity --- p.46 / Chapter 4.2.1 --- Toxicity of electroplating effluent samples on Microtox® test --- p.46 / Chapter 4.2.2 --- Toxicity of electroplating effluent samples on growth inhibition test of microalga Chlorella pyrenoidosa CU-2 --- p.46 / Chapter 4.2.3 --- Toxicity of electroplating effluent samples on survival test of amphipod Hyale crassicornis --- p.52 / Chapter 4.2.4 --- Toxicity of electroplating effluent samples on survival test of shrimp juvenile Metapenaeus ensis --- p.52 / Chapter 4.3 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.52 / Chapter 4.3.1 --- Toxicity Characterization of electroplating effluent samples using Microtox® test --- p.56 / Chapter 4.3.2 --- Toxicity Characterization of electroplating effluent samples using microalgal growth inhibition test of Chlorella pyrenoidosa CU-2 --- p.59 / Chapter 4.3.3 --- Toxicity Characterization of electroplating effluent samples using survival test of amphipod Hyale crassicornis --- p.65 / Chapter 4.3.4 --- Toxicity Characterization of electroplating effluent samples using survival test of shrimp juvenile Metapenaeus ensis --- p.68 / Chapter 4.4 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.73 / Chapter 4.4.1 --- Metal analysis on the electroplating effluents --- p.75 / Chapter 4.4.2 --- Effect of filter extraction test on toxicity recovery of the electroplating effluent samples --- p.75 / Chapter 4.4.2.1 --- Microtox® test --- p.75 / Chapter 4.4.2.2 --- Growth inhibition test of microalga Chlorella pyrenoidosa CU-2 --- p.75 / Chapter 4.4.2.3 --- Survival test of amphipod Hyale crassicornis --- p.81 / Chapter 4.4.2.4 --- Survival test of shrimp juvenile Metapenaeus ensis --- p.90 / Chapter 4.4.3 --- Effect of filter extraction test on metal ions recovery of the electroplating effluent samples --- p.90 / Chapter 4.5 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.96 / Chapter 4.5.1 --- Mass balance test results on Microtox® test --- p.96 / Chapter 4.5.2 --- Mass balance test results on survival test of amphipod Hyale crassicornis --- p.104 / Chapter 4.5.3 --- Spiking test results on Microtox® test --- p.106 / Chapter 4.5.4 --- Spiking test results on survival test of amphipod Hyale crassicornis --- p.113 / Chapter 5. --- DISCUSSION --- p.118 / Chapter 5.1 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity --- p.118 / Chapter 5.2 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.119 / Chapter 5.2.1 --- pH adjustment filtration test --- p.119 / Chapter 5.2.2 --- Aeration test --- p.120 / Chapter 5.2.3 --- C18 solid phase extraction test --- p.120 / Chapter 5.2.4 --- EDTA chelation test --- p.120 / Chapter 5.2.5 --- Graduated pH test --- p.121 / Chapter 5.3 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.122 / Chapter 5.3.1 --- Metal analysis on the electroplating effluents --- p.122 / Chapter 5.3.2 --- Effect of filter extraction test on toxicity and metal ions recovery of the electroplating effluent samples --- p.123 / Chapter 5.3.3 --- Comparison between the concentrations of the metal ions in the electroplating effluent samples with the Technical Memorandum on standards for effluent discharged --- p.124 / Chapter 5.3.4 --- Comparison between the concentrations of the metal ions in the electroplating effluent samples with the toxicity of the metal ions reported in the literature --- p.124 / Chapter 5.3.4.1 --- Microtox® test --- p.126 / Chapter 5.3.4.2 --- Microalga --- p.126 / Chapter 5.3.4.3 --- Amphipod --- p.126 / Chapter 5.3.4.4 --- Shrimp --- p.126 / Chapter 5.4 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.131 / Chapter 5.4.1 --- Mass balance test on Microtox® test --- p.132 / Chapter 5.4.2 --- Mass balance test on survival test of amphipod Hyale crassicornis --- p.133 / Chapter 5.4.3 --- Spiking test on Microtox® test --- p.133 / Chapter 5.4.4 --- Spiking test on survival test of amphipod Hyale crassicornis --- p.134 / Chapter 5.5 --- Toxicity of the Metal Ions Identified as the Toxicants in the Electroplating Effluent --- p.135 / Chapter 5.5.1 --- Copper --- p.135 / Chapter 5.5.2 --- Nickel --- p.137 / Chapter 5.5.3 --- Zinc --- p.138 / Chapter 5.6 --- Summary --- p.140 / Chapter 6. --- CONCLUSIONS --- p.142 / Chapter 7. --- REFERENCES --- p.144 / Chapter 7.1 --- APPENDIXES --- p.158

Leung Bo-Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 148-159). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.v / List of Abbreviations --- p.vi / List of Tables --- p.viii / List of Figures --- p.ix / Chapter 1 --- Introduction / Chapter 1.1 --- Food colorants --- p.1 / Chapter 1.2 --- Caramel --- p.3 / Chapter 1.2.1 --- Classes of caramel --- p.3 / Chapter 1.2.2 --- Toxicological studies of caramel --- p.5 / Chapter 1.3 --- Castanea mollissima --- p.9 / Chapter 1.4 --- Antioxidants --- p.10 / Chapter 1.4.1 --- Background --- p.10 / Chapter 1.4.2 --- Methods used to evaluate the antioxidative activity --- p.12 / Chapter 1.4.2.1 --- DPPH* scavenging method --- p.13 / Chapter 1.4.2.2 --- High performance liquid chromatography (HPLC) --- p.13 / Chapter 1.5 --- Microtox® test --- p.19 / Chapter 1.6 --- Mutatox® test --- p.19 / Chapter 1.7 --- Methods used to evaluate the functions of major organs --- p.20 / Chapter 1.7.1 --- Liver --- p.20 / Chapter 1.7.2 --- Kidneys --- p.23 / Chapter 1.8 --- Toxicology --- p.25 / Chapter 1.8.1 --- Acute toxicity test --- p.25 / Chapter 1.8.2 --- Chronic toxicity test --- p.26 / Chapter 1.9 --- Objective --- p.27 / Chapter 2 --- Materials and Methods --- p.28 / Chapter 2.1 --- Plant materials --- p.28 / Chapter 2.2 --- Sample preparation --- p.28 / Chapter 2.3 --- Pigment characterization --- p.30 / Chapter 2.3.1 --- Stability test --- p.30 / Chapter 2.3.2 --- HPLC separation of CP --- p.31 / Chapter 2.3.3 --- Determination of antioxidative activity with the DPPH* scavenging method --- p.31 / Chapter 2.4 --- Microtox® test --- p.33 / Chapter 2.5 --- Mutatox® test --- p.34 / Chapter 2.6 --- Acute toxicity test --- p.35 / Chapter 2.6.1 --- Animals --- p.35 / Chapter 2.6.2 --- Housing and maintenance --- p.35 / Chapter 2.6.3 --- Experimental design --- p.37 / Chapter 2.6.4 --- Chemicals --- p.39 / Chapter 2.6.5 --- Clinical pathology test --- p.41 / Chapter 2.6.5.1 --- Haematology --- p.41 / Chapter 2.6.5.2 --- Blood chemistry --- p.45 / Chapter 2.6.5.3 --- Urinalysis --- p.55 / Chapter 2.6.6 --- Histological study --- p.57 / Chapter 2.6.7 --- Statistical analysis --- p.57 / Chapter 2.7 --- Chronic toxicity test --- p.59 / Chapter 2.7.1 --- Animals --- p.59 / Chapter 2.7.2 --- Housing and maintenance --- p.59 / Chapter 2.7.3 --- Experimental design --- p.59 / Chapter 2.7.4 --- Chemicals --- p.60 / Chapter 2.7.5 --- Clinical pathology test --- p.61 / Chapter 2.7.5.1 --- Haematology --- p.61 / Chapter 2.7.5.2 --- Blood chemistry --- p.62 / Chapter 2.7.5.3 --- Urinalysis --- p.62 / Chapter 2.7.6 --- Histological study --- p.62 / Chapter 2.7.7 --- Statistical analysis --- p.62 / Chapter 3 --- Results --- p.63 / Chapter 3.1 --- Pigment characterization --- p.63 / Chapter 3.1.1 --- Stability test --- p.63 / Chapter 3.1.2 --- HPLC separation of CP --- p.63 / Chapter 3.1.3 --- Antioxidative activities of CP preparations --- p.63 / Chapter 3.2 --- Microtox® test --- p.65 / Chapter 3.3 --- Mutatox® test --- p.65 / Chapter 3.4 --- Acute toxicity test --- p.66 / Chapter 3.4.1 --- Growth rate --- p.66 / Chapter 3.4.2 --- Food and fluid consumption --- p.66 / Chapter 3.4.3 --- Organ-weight --- p.66 / Chapter 3.4.4 --- Clinical pathology tests --- p.68 / Chapter 3.4.4.1 --- Haematology --- p.68 / Chapter 3.4.4.2 --- Blood chemistry --- p.70 / Chapter 3.4.4.3 --- Urinalysis --- p.76 / Chapter 3.4.5 --- Histological study --- p.76 / Chapter 3.5 --- Chronic toxicity test --- p.77 / Chapter 3.5.1 --- Growth rate --- p.77 / Chapter 3.5.2 --- Food and fluid consumption --- p.77 / Chapter 3.5.3 --- Organ-weight --- p.77 / Chapter 3.5.4 --- Clinical pathology tests --- p.78 / Chapter 3.5.4.1 --- Haematology --- p.78 / Chapter 3.5.4.2 --- Blood chemistry --- p.80 / Chapter 3.5.4.3 --- Urinalysis --- p.82 / Chapter 3.5.5 --- Histological study --- p.82 / Chapter 4 --- Discussion --- p.137 / Chapter 4.1 --- Pigment characterization --- p.137 / Chapter 4.2 --- Toxicological studies of CP --- p.140 / Chapter 5 --- Conclusion --- p.147 / References --- p.148

Two specific goals were addressed for this dissertation. First to investigate and identify the mechanistic profile of ketoconazole (KT)-induced hepatotoxicity by utilizing in vivo and in vitro approaches determining the mechanism of action for the hepatotoxicity incurred. To date, there has not been a mechanistic determination of the hepatotoxicity associated with KT in vivo. This dissertation evaluates the possible metabolic bioactivation of KT by cytochrome-P450 (CYP) or flavin-containing monooxygenases (FMO) resulting in covalent binding with hepatic macromolecules. The hypothesis of this study was to reveal whether covalent binding by the parent compound, KT, and/or reactive metabolites produces hepatic damage associated with increased serum alanine aminotransaminase (ALT) release and decreased hepatic glutathione (GSH). The first objective was determination of in vivo covalent binding in a dose-time response comparison in Sprague-Dawley (SD) rat ALT and GSH levels. Increased ALT and reduced hepatic GSH levels occurred. The second objective was an in vitro comparison of covalent binding with GSH levels utilizing SD microsomal protein with incubations of KT. Covalent binding decreased with added GSH to microsomal incubations. Thirdly, correlate in vivo with in vitro findings. Covalent binding of KT in vivo and in vitro occurred with increased doses and time. The final objective was to determine the bioactivation pathway utilizing heat inactivation and no NADPH in vitro. Covalent binding of KT decreased in the absence of NADPH and deactivation of FMO. The second goal was to determine and quantitate in vitro the presence of FMO isozymes in microsomes of the human intestinal duodenum, jejunum, ileum, and colon as well as the Caco-2 (HTB-37), epithelial intestinal (CCL-241) and colon (CRL1790) cell lines. The presence of FMO could result in a first-pass effect decreasing the bioavailability of soft nucleophiles or a toxicity effect due to inhibition or modulation of the enzyme from co-administration. To date, this is the first evaluation of FMO isoforms in human intestine and cell lines. Western blot techniques were utilized for detection of human FMO1, FMO3, and FMO5 using human FMO-expressed recombinant cDNA from a baculovirus system. / Graduation date: 2003