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- Lundgren, Bo, et al.
(författare)
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Characterization of the induction of cytosolic and microsomal epoxide hydrolases by 2-ethylhexanoic acid in mouse liver.
- 1987
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Ingår i: Drug Metabolism And Disposition. - 0090-9556 .- 1521-009X. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- When mice were exposed to 1% 2-ethylhexanoic acid in the diet, cytosolic and microsomal epoxide hydrolase (EC 3.3.2.3) activities were increased maximally (2-2.5- and 0.5-1-fold, respectively) after 3 days. Immunochemical quantitation of these enzymes indicated that the process involved was a true induction in both cases. Maximal levels of peroxisome proliferation (as indicated by carnitine acetyltransferase activity) were obtained after 7 days of exposure. All three of these activities returned to control levels within 4 days after termination of the treatment. The liver somatic index was slightly increased after 4 days of administration of 1% 2-ethylhexanoic acid, but the protein contents of the "mitochondrial," microsomal, and cytosolic fractions were unaffected. The activity of peroxisomal palmitoyl-CoA beta-oxidation was increased 2-fold, whereas peroxisomal catalase activity was unaffected. Exposure to 2-ethylhexanoic acid also increased cytochrome oxidase activity, suggesting an effect on mitochondria. Other parameters of detoxication--i.e. total microsomal cytochrome P-450 content, cytosolic glutathione transferase activity toward 1-chloro-2,4-dinitrobenzene, and the "cytosolic" epoxide hydrolase activity localized in the "mitochondrial" fraction--were not affected by 4 days of treatment with 1% 2-ethylhexanoic acid.
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- Lundgren, Bo, et al.
(författare)
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Induction of cytosolic and microsomal epoxide hydrolases in mouse liver by peroxisome proliferators, with special emphasis on structural analogues of 2-ethylhexanoic acid.
- 1988
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Ingår i: Chemico-Biological Interactions. - 0009-2797 .- 1872-7786. ; 68:3-4
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Tidskriftsartikel (refereegranskat)abstract
- Using dietary administration, mice were exposed to eight substances known to cause peroxisome proliferation (i.e. clofibrate clofibric acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, nafenopin, ICI-55.897, S-8527 and Wy-14.643) or the related substance p-chlorophenoxyacetic acid (group A). Other animals received di(2-ethylhexyl)phthalate, mono(2-ethylhexyl)phthalate, 2-ethylhexanoic acid, or one of 12 other metabolically and/or structurally related compounds (group B). The effects of these treatments on liver cytosolic and microsomal epoxide hydrolases, microsomal cytochrome P-450, cytosolic glutathione transferase activity, the liver-somatic index and the protein contents of the microsomal and cytosolic fractions prepared from liver were subsequently monitored. In general, peroxisome proliferation was accompanied by increases in cytosolic epoxide hydrolase activity. Many peroxisome proliferators also caused increases in microsomal epoxide hydrolase activity, although the correlation was poorer in this case. Immunochemical quantitation by radial immunodiffusion demonstrated that the increases observed in both of these enzyme activities reflected equivalent increases in enzyme protein, i.e. that induction truly occurred. Induction of total microsomal cytochrome P-450 was obtained after dietary exposure to clofibrate, clofibric acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, nafenopin, Wy-14.643, di(2-ethylhexyl)phthalate and di(2-ethylhexyl)phosphate. The most pronounced effects on cytosolic glutathione transferase activity were the decreases obtained after treatment with clofibrate, clofibric acid and Wy-14.643. Our results, together with those reported by others, suggest that the processes of peroxisome proliferation and induction of cytosolic epoxide hydrolase are intimately related. One possible explanation for this is presented.
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- Lundgren, Bo, 1955-
(författare)
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Off-flavours in drinking water : Analytical procedures and treatment effects in biologically active sand filters
- 1989
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Taste and odour problems in drinking water are primarily caused by naturally produced, volatile, organic compounds. So far, research in this field has focused on a relatively small number of known compounds. However, several results indicate that the origin of objectionable tastes and odours in water can be attributed to a much larger group of compounds, many of them so far unidentified.The complex composition of off· flavours in drinking water calls for a systematic method of establishing cause-effect relationships. In the present study such a method was developed. After enrichment of odorous organic compounds by stripping, solvent extraction and adsorption on XAD-2, the extracts obtained were fractionated by preparative gas chromatography with subsequent sensory evaluation of the fractionsredissolved in water. It is suggested that this technique, in combination with chromatographic sniffing, may play a crucial role in isolation and identification of the compounds causing the off· flavour of a water sample.Abatement of off-flavours in water is mainly accomplished by means of different filtration techniques. In the present study, the removal of off-flavour compounds during filtration through biologically active sand filters was investigated. This was done during both full-scale operation of the artificial ground water recharge technique and laboratory-scale column experiments with or without pretreatment with ozone. The efficient removal of off-flavours obtained in the sand filters studied, demonstrated the potential of treatment methods based on biological activity. Artificial groundwater recharge and related sand filtration techniques deserve an increased attention in drinking water treatment.
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- Lundgren, Bo, et al.
(författare)
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Proliferation of peroxisomes and induction of cytosolic and microsomal epoxide hydrolases in different strains of mice and rats after dietary treatment with clofibrate.
- 1989
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Ingår i: Xenobiotica. - 0049-8254 .- 1366-5928. ; 19:8
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Tidskriftsartikel (refereegranskat)abstract
- 1. The effects of dietary clofibrate (0.5%, w/w, for 10 days) on seven inbred strains of mice--C57BL/6, C57BL/B10A(5R), ATL/OLA, C3H/HE/OLA, BALB/C, CBA/CA and A/J/OLA--and three strains of rats--Sprague-Dawley, Wistar and LOU/OLA--have been investigated. Liver weight, peroxisome proliferation, catalase activity, cytosolic, microsomal and mitochondrial epoxide hydrolase activities, cytochrome oxidase activity, microsomal cytochrome P-450 content and cytosolic glutathione transferase activity in liver were determined, together with cytosolic and microsomal epoxide hydrolase and cytosolic glutathione transferase activities in the kidneys. 2. In all cases peroxisome proliferation and induction of cytosolic epoxide hydrolase were observed in livers of rodents exposed to clofibrate. Thus, no non-responsive strains were found and further evidence for a coupling between these two phenomena was provided. In many cases significant increases in the liver microsomal cytochrome P-450 content and decreases in the hepatic cytosolic glutathione transferase activity were also seen. 3. High levels of cytosolic epoxide hydrolase were found in the rat kidney. In several strains of mice and rats renal cytosolic epoxide hydrolase activity was increased by clofibrate. 4. There were often considerable strain differences. However, in general mice had higher cytosolic epoxide hydrolase and glutathione transferase activities, whereas rats had higher microsomal epoxide hydrolase activities.
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