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.

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.

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.

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.

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.