Behavioral and thyroid effects of in utero and lactational exposure of Sprague-Dawley rats to the polybrominated diphenyl ether mixture DE71.

Exposure of rodents during gestation and lactation to polybrominated diphenyl ethers (PBDEs) has been reported to disrupt neurobehavioral function in offspring, as well as to disrupt thyroid function. To assess this we evaluated development and behavior after gestational and lactational exposure to the technical PBDE mixture DE71. Pregnant Sprague-Dawley rats were exposed to 0, 0.

Effects of environmentally relevant mixtures of persistent organic pollutants on the developmental neurobiology in rats.

We report the developmental neuropathology for rat pups at postnatal day (PND) 37 and PND 77 and the molecular biomarkers for PND 35, 75, and 350 after perinatal exposure to a reconstituted mixture of persistent organochlorine pollutants (POPs) based on the blood profiles of people living in the Great Lake Basin. The developmental neuropathology included routine histopathology evaluation, quantification of cell proliferation and death in the subventricular zone, linear morphometric measurements, and transcriptional analysis. No histopathological, structural, or stereological changes were observed in animals treated with the POPs or Aroclor 1254, on PND 37 or PND 77.

Effects of anesthetics and terminal procedures on biochemical and hormonal measurements in polychlorinated biphenyl treated rats.

This investigation reports the effects of various terminal procedures, and how they modified the responses to a toxicant (polychlorinated biphenyls [A1254], 130 mg/kg/day × 5 days) administered by gavage to Sprague-Dawley male rats. Terminal procedures included exsanguination via the abdominal aorta under anesthesia (isoflurane inhalation or Equithesin injection), decapitation with or without anesthesia, or narcosis induced by carbon dioxide inhalation. Effects of repeated anesthesia were also tested.

Assessment of subclinical, toxicant-induced hepatic gene expression profiles after low-dose, short-term exposures in mice.

Gene expression profiling that examines critical, toxicologically-relevant gene and signal-response pathways promises to improve risk assessment and safety evaluation of low-dose chemical exposures. As an approach to achieving this goal, mechanistic interpretations based upon gene expression changes that are determinants of adverse toxicological outcomes were applied to the analysis of low-dose gene expression profiles. RNA for expression profiling was obtained from mice given short-term gavage exposures to diminishing doses of four toxicants: 3,3',4,4',5-pentachlorobiphenyl (PCB126), phenobarbital (PB), isoproterenol (IPR), and lead acetate (PbAc).

Use of biomarkers to show sub-cellular effects in meadow voles (Microtus pennsylvanicus) living on an abandoned gold mine site.

Run-off from mine tailings ponds constitutes the main anthropogenic release of arsenic in Canada. As a potential consequence, wildlife not normally exposed to arsenic under other circumstances may receive toxicologically relevant concentrations of arsenic compounds in their food and water. To test this hypothesis, and to determine if arsenic is being transported through trophic levels, the arsenic concentrations in members of a short food chain (soil-plant-meadow vole) were measured.

Toxicological effects of in utero and lactational exposure of rats to a mixture of environmental contaminants detected in Canadian Arctic human populations.

As part of the program to investigate mixture effects of environmental pollutants, this study describes clinical, biochemical, and histopathological effects in rats perinatally exposed to a mixture of persistent organochlorine pollutants and methylmercury that simulates the blood contaminant profile of humans residing in the Canadian Arctic. Groups of pregnant rats were administered orally 0, 0.05, 0.

Effects of three biodiesels and a low sulfur diesel in male rats--a pilot 4-week oral study.

Because of the accessible and renewable nature of feedstock and the potential for the reduction of harmful combustion emissions and greenhouse gases, biodiesels have received increasing interest as an alternate fuel. Oral exposure to biodiesels is a concern because of contact during refuelling, accidental ingestion and exposure through ground water contamination. Although biodiesels from various feedstock are in use commercially and experimentally, very little is known about their potential adverse effects and no data is available on their potential for ground water contamination.

Toxicological effects of gestational and lactational exposure to a mixture of persistent organochlorines in rats: systemic effects.

A large multi-disciplinary study was conducted to investigate the systemic, neurodevelopmental, neurochemical, endocrine, and molecular pathological effects of a mixture of reconstituted persistent organochlorine pollutants (POP) based on the blood profiles of Canadians residing in the Great Lakes/St. Lawrence region. This report outlines the overall study design and describes the systemic effects in rat offspring perinatally exposed to the POP mixture.

Effects of postnatal exposure to a mixture of polychlorinated biphenyls, p,p'-dichlorodiphenyltrichloroethane, and p-p'-dichlorodiphenyldichloroethene in prepubertal and adult female Sprague-Dawley rats.

The postnatal period is a critical phase of development and a time during which humans are exposed to higher levels of persistent organic pollutants (POPs), than during subsequent periods of life. There is a paucity of information describing effects of postnatal exposure to environmentally relevant mixtures of POPs, such as polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyltrichloroethane (DDT), and p,p'-dichlorodiphenyldichloroethene (DDE). To provide data useful for the risk assessment of postnatal exposure to POPs, mixtures containing 19 PCBs, DDT, and DDE were prepared according to their concentrations previously measured in the milk of Canadian women, and dose-response effects were tested on the proliferation of MCF7-E3 cells in vitro, and in vivo experiments.

90-day repeated inhalation exposure of surfactant Protein-C/tumor necrosis factor-alpha, (SP-C/TNF-alpha) transgenic mice to air pollutants.

Tumor necrosis factor (TNF)-alpha, a cytokine present in inflammed lungs, is known to mediate some of the adverse effects of ozone and inhaled particles. The authors evaluated transgenic mice with constitutive pulmonary expression of TNF-alpha under transcriptional regulation of the surfactant protein-C promoter as an animal model of biological susceptibility to air pollutants. To simulate a repeated, episodic exposure to air pollutants, wild-type and TNF mice inhaled air or a mixture of ozone (0.

Effects of an ethanol-gasoline mixture: results of a 4-week inhalation study in rats.

The inhalation toxicity of an ethanol-gasoline mixture was investigated in rats. Groups of 15 male and 15 female rats were exposed by inhalation to 6130 ppm ethanol, 500 ppm gasoline or a mixture of 85% ethanol and 15% gasoline (by volume, 6130 ppm ethanol and 500 ppm gasoline), 6 h a day, 5 days per week for 4 weeks. Control rats of both genders received HEPA/charcoal-filtered room air.

Early developmental neurotoxicity of a PCB/organochlorine mixture in rodents after gestational and lactational exposure.

The developmental and neurobehavioral effects of gestational and lactational exposure to a mixture of 14 polychlorinated biphenyls (PCBs) and 11 organochlorine pesticides was examined and compared against the commercial PCB mixture Aroclor 1254. The mixture was based on blood levels reported in Canadian populations living in the Great Lakes/St. Lawrence basin.

Effects of postnatal exposure to mixtures of non-ortho-PCBs, PCDDs, and PCDFs in prepubertal female rats.

There are concerns that postnatal exposure to organochlorines present in breast milk could lead to adverse health effects. We reconstituted four mixtures of aryl-hydrocarbon receptor (AhR) agonists (3 non-ortho polychlorinated biphenyls [PCBs], 6 polychlorinated dibenzodioxins [PCDDs], 7 polychlorinated dibenzofurans [PCDFs], or all 16 chemicals together [referred to as AhRM]) based on their concentrations in breast milk, and examined their effects following exposure by gavage from day 1 until day 20 of age. Female neonates received dosages of AhRM equivalent to 1, 10, 100, or 1000 times the amount consumed by an infant over the first 24 days of life.

Effects of dibromoacetonitrile on rats following 13-week drinking water exposure.

The subchronic toxicity of dibromoacetonitrile (DBAN), a disinfection by-product in drinking water, was studied in the rat. Male (180+/-18 g) and female (152+/-9 g) Sprague-Dawley rats (10 animals per group) were fed DBAN in organic-free distilled water at concentrations of 0.1, 1, 10 and 100 ppm for 13 weeks.

Subchronic toxicity of Baltic herring oil and its fractions in the rat II: Clinical observations and toxicological parameters.

This study aimed to increase the knowledge about the toxicity of fish-derived organohalogen pollutants in mammals. The strategy chosen was to separate organohalogen pollutants derived from Baltic herring (Clupea harengus) fillet, in order to obtain fractions with differing proportions of identified and unidentified halogenated pollutants, and to perform a subchronic toxicity study in rats, essentially according to the OECD guidelines, at three dose levels. Nordic Sea lodda (Mallotus villosus) oil, with low levels of persistent organohalogen pollutants, was used as an additional control diet.

Subchronic toxicity of chloral hydrate on rats: a drinking water study.

The subchronic toxicity of chloral hydrate, a disinfection byproduct, was studied in rats following 13 weeks of drinking water exposure. Male (262 +/- 10 g) and female (190 +/- 8 g) Sprague-Dawley rats, ten animals per group, were administered chloral hydrate via drinking water at 0.2, 2, 20 and 200 ppm.

Effects of subchronic exposure to a complex mixture of persistent contaminants in male rats: systemic, immune, and reproductive effects.

Human populations throughout the world are exposed daily to low levels of environmental contaminants. The consequences of potential interactions of these compounds to human endocrine, reproductive, and immune function remain unknown. The current study examines the effects of subchronic oral exposure to a complex mixture of ubiquitous persistent environmental contaminants that have been quantified in human reproductive tissues.

Short-term oral toxicity of gasohol in female rats.

The systemic toxicity of gasohol (10% ethanol in gasoline by volume) in female rats following 4-week oral administration was studied. Female Sprague-Dawley rats (198+/-14 g) were divided into four groups of ten animals each. The low- and medium-dose groups received by gavage corn oil containing gasoline/ethanol at 16/1.

Mixture effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and polychlorinated biphenyl congeners in rats.

Concern of the toxic effects and bioaccumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls in the environment continues to be a focus of research in persistent organochlorine contaminants. Groups of five adult female S.D.

Effects of subchronic exposure of rats to dichloramine and trichloramine in drinking water.

The subchronic toxicity of 0.2-200 ppm dichloramine and 0.2-90 ppm trichloramine in the drinking water of rats was investigated using biochemical, hematological, and histopathological parameters.

Effects of bis(4-chlorophenyl) sulfone on rats following 28-day dietary exposure.

The short-term oral toxicity of a recently identified environmental pollutant, bis(4-chlorophenyl) sulfone (BCPS), was studied. Groups of male Sprague-Dawley rats (n = 6) were administered BCPS via the diet at 0 (control), 10, 100, or 1000 ppm for 4 wk. Additional control and 1000 ppm groups were also treated for 1, 2, and 3 wk.

Effects of acute exposure to PCBs 126 and 153 on anterior pituitary and thyroid hormones and FSH isoforms in adult Sprague Dawley male rats.

3,3'4,4',5-Pentachlorobiphenyl (PCB 126) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) were administered to adult male rats in order to identify sensitive indicators of endocrine disruption. We tested the hypothesis that PCB exposure modifies follicle-stimulating hormone (FSH) pituitary isoforms, as well as the pituitary and serum concentrations of FSH, luteinizing hormone (LH), growth hormone, prolactin, and thyroid-stimulating hormone (TSH). Effects on serum levels of thyroxine (T4) and testosterone (T), and prostate androgen receptor content, were also tested.

Subchronic toxicity of benzothiophene on rats following dietary exposure.

The systemic and neurobehavioral effects of benzo[b]thiophene (routinely referred to as benzothiophene) were studied in rats following 13-wk oral exposure. Male (170 +/- 16 g) and female (146 +/- 12 g) Sprague-Dawley rats (10 animals per group) were fed diet containing 0.5, 5, 50, or 500 ppm benzothiophene for 13 wk.

Subchronic toxicity of PCB 105 (2,3,3',4,4'-pentachlorobiphenyl) in rats.

The toxicity of 2,3,3',4,4'-pentachlorobiphenyl (PCB 105) was investigated in Sprague-Dawley rats following dietary exposure to this substance at levels of 0, 0.05, 0.5, 5 or 50 ppm for 13 weeks.

Uranyl nitrate: 91-day exposure and recovery studies in the male New Zealand white rabbit.

This study was undertaken to examine the reversibility of renal injury in the male New Zealand White rabbit subsequent to a 91-day exposure to uranyl nitrate (UN) in drinking water, followed by various recovery periods. Specific pathogen-free (SPF) animals were exposed for 91 days to UN in their drinking water (24 or 600 mg UN/L). Control groups were given municipal tap water (< 0.