Reported here is an investigation to determine if azinphos-methyl (AZM), an
organophosphate insecticide, adducts to hemoglobin, and if so, whether the
hemoglobin adduct could be used as a quantitative marker of occupational AZM
exposure. We hypothesized that AZM, or a metabolite of AZM, binds to hemoglobin
in erythrocytes forming an...
Exposure to TCDD suppresses the generation of immune responses through unknown mechanisms. Interestingly, TCDD enhances inflammatory responses to various stimuli. The goal of the studies presented in this thesis was to examine the role of hyperinflammation in TCDD-induced immunotoxicity. Previously we observed an increase in Mac-1⁺ cells in the spleen...
Indole-3-carbinol (I3C), the most abundant metabolite of glucobrassicins, is
found in cruciferous vegetables such as broccoli, Brussels sprouts, cabbage and
cauliflower. I3C has been shown to have anticarcinogenic activity against many
chemical carcinogens in multiple target organs in animal models. However, the
anticarcinogenic activity of I3C is considered indirect since...
T cell-dependent immune responses are highly sensitive to suppression by
exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin
(TCDD), yet direct effects of TCDD on T cells have been difficult to demonstrate.
Because the activation of naive T cells is initiated by dendritic cells (DC), the studies
presented in this dissertation were...
Reported here is an investigation to determine the in vitro and in vivo metabolism
of xanthohumol (XN). XN is the major prenylated flavonoid of the female
inflorescences (cones) of the hop plant (Humulus lupulus). It is also a constituent of
beer, the major dietary source of prenylated flavonoids. Recent studies...
In experimentally exposed mice, the environmental contaminant 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) produces significant suppression of adaptive immune responses at low doses. However, the underlying biochemical and cellular mechanisms of TCDD-induced immunotoxicity have remained elusive since the identification of these effects nearly 30 years ago. Antigen-presenting cells (APC) constitute various populations of...
The pyrrolizidine alkaloids (PAs) and ergot alkaloids are known natural toxicants found in livestock forage. These alkaloids contribute to large economic losses in livestock throughout the world. An understanding of the mechanisms of toxicity and development of better diagnostic tools for better management practices was investigated. Variability exists in the...
Chlorophyllin (CHL), a water-soluble derivative of the green plant pigment, chlorophyll, is an effective antimutagen and anticarcinogen in various model systems when used as a modulator against a class of carcinogens that, in general, have a structure consisting of at least three fused rings. Dibenzo[a,l]pyrene (DBP), an extremely potent environmental...
Previous studies have shown that rainbow trout exposed to dieldrin via diet for 9 to 12 weeks increased biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500%. This was not explained by induction of the cytochrome P-450 (CYP) system involved in oxidative metabolism of these compounds. We hypothesized that...
The aim of this study was to assess sensitivity of early life stage zebrafish to cadmium (Cd). Embryos and larva were exposed to Cd before the formation of skeletal elements. Exposure times were selected to determine whether Cd perturbed developmental processes that lead to skeletal deformities, and to characterize the...
Rat selenoprotein W (SeW) promoter activity was investigated using different concentrations of cadmium, copper, and zinc. Two fragments (404bp and 1265bp) of the SeW promoter, containing a single metal response element (MRE), were ligated into the multiple cloning site of a pGL3-Basic reporter plasmid. The constructs were transfected into cultured...
This study was designed to assess chiorpyrifos exposure of a group of farmers by determining internal dose associated with a given application of this insecticide. This involved the monitoring of urinary levels of 3,5,6 trichloro-2-pyridinol (TCP), the major metabolite of chlorpyrifos. Incidental exposure was evaluated by determining the levels of...
Feeding rainbow trout 0.3-0.4 mg dieldrinlkg/d for 9-12 weeks stimulated the biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500% and [³H]7,12- dimethylbenz[a]anthracene (DMBA) by 240%. In vitro work demonstrated that this interaction occurred without induction of the cytochrome P450 system, or other hepatocellular proteins involved in metabolism. The...
The Cottage Grove Reservoir has been impacted by a point source (Black Butte Mine), where mercury mining and processing has occurred within its watershed from the 1890's to the late 1960's. Total mercury concentrations in surface sediments transect samples, core samples, tributary samples, and representative food web species were measured...
Previous work (Thorgaard, G. H. et al., Aquatic Toxicology 46:121-126, 1999)
showed triploid rainbow trout (0. mykiss) given embryonic carcinogen bath exposures
had significant reduction of induced tumors relative to diploids. In the present study,
trout were made triploid by thermal shock after fertilization. At age of 5 months they...
Due to its frequent use in agriculture and its frequent detection in surface water,
atrazine was chosen as a model compound to study the treatment capability of a surface flow wetland used to remediate irrigation runoff at a container nursery near Portland, Oregon. Further evaluation of treatment of atrazine was...