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20 results on '"Østergaard G"'

1. Changes in markers of oxidative status in brain, liver and kidney of young and aged rats following exposure to aromatic white spirit

Author

Bondy, SC, Lam, HR, Østergaard, G, Guo, SX, and Ladefoged, Ø

Subjects
Pharmacology and Pharmaceutical Sciences, Biomedical and Clinical Sciences, Neurosciences, Digestive Diseases, Mental Health, Liver Disease, Depression, Kidney Disease, Aging, Animals, Brain, Chemical Fractionation, Glutamate-Ammonia Ligase, Glutathione, Hydrocarbons, Kidney, Liver, Male, Oxidative Stress, Rats, Rats, Wistar, Solvents, Spectrophotometry, Ultraviolet, Tissue Distribution, SOLVENTS, AROMATICS, FREE RADICALS, REACTIVE OXYGEN, OXIDATIVE STRESS, SYNAPTOSOMES, Toxicology, Biochemistry and cell biology, Pharmacology and pharmaceutical sciences
Abstract

Levels of glutathione and activity of glutamine synthetase were assayed in organs of rats following inhalation of a heterogeneous solvent mixture containing both aliphatic and aromatic hydrocarbons. This mixture was administered for 3 weeks (6 h daily) at two levels in the inhaled air (400 and 800 ppm) to young adult (5-month-old) and aged (14-month-old) rats. Depression of levels of glutamine synthetase in the P2 fraction of kidney was observed, which was more severe in aged than young adult rats. Glutamine synthetase is a cytosolic enzyme especially susceptible to oxidative damage. A parallel depression of this enzyme was also seen in the corresponding hepatic fractions. However, levels of glutamine synthetase in the hippocampus were elevated by this exposure. Glutathione levels were depressed in P2 fractions of livers of exposed rats, and also in the corresponding renal fraction. Glutathione concentration was unchanged in cerebral fractions. Overall results were interpreted to imply that pro-oxidant events were elevated in kidney and liver following prolonged inhalation of the solvent mixture. The changes found in brain tissue did not reveal evidence of oxidative stress but, however, suggested that glial activation was taking place.

Published
1995

2. Three weeks' exposure of rats to dearomatized white spirit modifies indices of oxidative stress in brain, kidney, and liver

Author

Lam, HR, Østergaard, G, Guo, SX, Ladefoged, O, and Bondy, SC

Subjects
Medical Biotechnology, Biomedical and Clinical Sciences, Neurosciences, Digestive Diseases, Liver Disease, Animals, Body Weight, Drinking, Eating, Glutamate-Ammonia Ligase, Glutathione, Hippocampus, Hydrocarbons, Kidney, Liver, Male, Mucous Membrane, Rats, Reactive Oxygen Species, Subcellular Fractions, ORGANIC SOLVENTS, NEUROTOXICITY, SYNAPTOSOMES, REACTIVE OXYGEN SPECIES, EXXSOL D 40, Biochemistry and Cell Biology, Pharmacology and Pharmaceutical Sciences, Pharmacology & Pharmacy, Biochemistry and cell biology, Pharmacology and pharmaceutical sciences
Abstract

The present study was undertaken in order to investigate whether dearomatized white spirit induces indices of oxidative stress in subcellular fractions of hemisphere, hippocampus, kidney and liver tissue of rats exposed to 0, 400 and 800 ppm 6 hr/day, 7 days a week for 3 weeks. The results show that white spirit is a strong in vivo inducer of oxidative stress in subcellular fractions of brain, kidney and liver. In the liver there was a statistically significant increase in the rate of reactive oxygen species (ROS) generation and a decrease in glutamine synthetase activity. In the kidney there was a statistically significant decrease in the rate of ROS generation. In the hemisphere there was a statistically significant increase in the level of reduced glutathione. In the hippocampus there was a statistically significant increase in the rate of ROS generation. However, in vitro addition of dearomatized white spirit had no effect on the rate of cerebrocortical P2 fraction ROS generation. The results suggest that cumulative oxidative damage may be an underlying mechanism of dearomatized white spirit-induced neurotoxicity and that various regions of the brain may respond differently.

Published
1994

11. Children and the unborn child, Exposure and susceptibility to chemical substances – an evaluation:Report to the Danish Environmental Protection Agency

Author

Nielsen, Elsa, Thorup, I., Schnipper, Anette, Hass, Ulla, Meyer, Otto A., Ladefoged, Ole, Larsen, John Christian, Østergaard, G., Sørensen, T. L., and Larsen, P. B.

Abstract

Children are at risk of exposure to a lot of high-production-volume synthetic chemical substances which have been introduced into the market within the past 50 years; these chemical substances are used widely in consumer products and are dispersed in the environment. Children as well as the unborn child have in some cases appeared to be uniquely vulnerable to chemical toxicants because of their biological growth and development. Furthermore, children may be more heavily exposed than adults to certain chemicals and pollutants in the environment. This report summarises and discusses the current knowledge about the biological susceptibility and exposure of chemical substances to children during the embryonic, foetal, and postnatal periods.

Published
2001

12. Repeated dose 28-day oral toxicity study in Wistar rats with a mixture of five pesticides often found as residues in food: alphacypermethrin, bromopropylate, carbendazim, chlorpyrifos and mancozeb

Author

Jacobsen, H., Østergaard, G., Lam, Henrik Rye, Poulsen, Mette Erecius, Frandsen, Henrik Lauritz, Ladefoged, Ole, Meyer, Otto A., Jacobsen, H., Østergaard, G., Lam, Henrik Rye, Poulsen, Mette Erecius, Frandsen, Henrik Lauritz, Ladefoged, Ole, and Meyer, Otto A.

Abstract

Six dose groups of 8 male and female rats respectively received a daily dose equivalent to 0, 0.15, 0.006, 0.03, 0.15 or 0.3 mg/kg b.w./day chlorpyrifos (groups 1-6) and the last four dose groups (groups 3-6) received in addition daily doses equivalent to 18 mg/kg b.w./day alphacypermethrin, 30 mg/kg b.w./day bromopropylate, 45 mg/kg b.w./day carbendazim and 12.5 mg/kg b.w./day mancozeb for 28 days. Plasma acetylcholinesterase was significantly decreased in the groups 2, 5 and 6 males. Total white blood cell count was significantly lower in females of group 6. Total red blood cell count, haematocrite and haemoglobin concentration was significantly reduced in both male and female rats of groups 5 and 6. Relative liver weight was significantly increased in groups 3-6 male and female rats. Absolute thyroid gland weight was significantly increased in groups 3, 5 and 6 male rats and of groups 3-6 female rats, and relative thyroid gland weight was significantly increased in groups 2-6 male rats and of groups 3-6 female rats. Absolute thymus weight of groups 3-6 male and female rats and relative thymus weight of groups 3-6 male rats and groups 3 and 4 female rats was significantly decreased. A mild degree of centrilobular cell hypertrophy of the liver was seen in all male rats and of three female rats of group 6. In the thyroid gland follicular cell hypertrophy was present in one female in the control group and in six females and seven males of group 6. It was concluded that inhibition of acetylcholinesterase activity in plasma and brain by chlorpyrifos was not enhanced by coadministration of the other four pesticides. Effects were seen in liver, thyroid, thymus and blood in the combination groups. However, identification of the pesticide(s) responsible for these changes would require further studies of the individually pesticides as well as various combinations of the pesticides.

Published
2004

13. In Vivo Investigation of Dietary Exposure to 5 Pesticides

Author

Jacobsen, H., Østergaard, G., Lam, Henrik Rye, Poulsen, Mette Erecius, Frandsen, Henrik Lauritz, Ladefoged, Ole, Meyer, Otto A., Jacobsen, H., Østergaard, G., Lam, Henrik Rye, Poulsen, Mette Erecius, Frandsen, Henrik Lauritz, Ladefoged, Ole, and Meyer, Otto A.

Published
2003

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