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142 results on '"Øvrebø, Steinar"'

103. Examination of nervous system effects and other health effects in tunnel workers exposed to acrylamide and N-methylolacrylamide in Romeriksporten, Norway

Author

Kjuus, Helge, Goffeng, Lars Ole, Heier, Mona Skard, Øvrebø, Steinar, Skaug, Vidar, Ryberg, David, Sjöholm, Hans, Hansteen, Inger-Lise, Törnqvist, Margretha, Paulsson, Birgit, Langeland, Bjørn T., Brudal, Stein, and Foss, Ørn Terje

Subjects
Acrylamide, Glutathion-S-transferase, Nerve conduction, Kromosomskader, Symptomer, Chromosmal aberrations, Akrylamid, Reversibilitet, Nerveledning, Hemoglobin addukter, N-methylolacrylamide, Hemoglobin adducts, Reversibility, Tunnelarbeidere, Grouting agent, Symptoms, Perifere nervesystem, Peripheral nervous system, N-methylolakrylamid, Tunnel workers, Injeksjonsmidler
Abstract

OBJECTIVES: This study examined nervous system effects and other health effects in tunnel workers exposed to acrylamide and N-methylolacrylamide during tunnel work. METHODS: Symptoms and nerve conduction properties were recorded in 25 tunnel workers exposed to acrylamide and N-methylolacrylamide during grouting operations, four and 16 months after the cessation of exposure. Visual evoked response (VEP) and electroretinography (ERG) were performed 16 months post exposure. Hemoglobin adducts of acrylamide were measured and qualitative exposure indices were developed. Fifty unexposed tunnel workers served as referents. Chromosome aberrations and the distribution of Glutathion S transferase (GST) genotypes (M and T) were also examined in the 25 exposed workers, and were compared to 25 age and smoking matched referents. RESULTS: The exposed workers reported an increased prevalence of symptoms during grouting work compared to the examination after 16 months. A statistically significant reduction in mean sensory nerve conduction velocity (NCV) in the ulnar nerve was observed 4 months post exposure when compared to the reference group (52.3 vs. 58.9 m/s, p=0.001), and mean ulnar distal delay was prolonged (3.1 vs 2.5ms, p=0.001). Both measures were significantly improved when measured one year later. By correlating outcome measurements with the qualitative exposure indices of the individual workers, exposure-related improvements from four to 16 months post exposure were observed both in the median nerve (motor and sensory NCV and F-response) and the ulnar nerve (sensory NCV, F-response). A significant reversible reduction in the mean sensory amplitude in the median nerve was also observed, while sensory amplitudes in the sural nerve were significantly reduced after 16 months. The amplitudes in the electroretinography on photoptic (30 Hz) stimulation were significantly lower in the exposed subjects compared to the referents. There were no clear differences in the neurophysiological outcome parameters related to GST genotypes M and T. Chromosome examinations showed no significant differences between the 25 exposed subjects and 25 of the referents for chromosome aberrations, chromatid breaks, chromosome breaks and chromosome gaps. A significant increase in chromatid gaps was observed in the exposed subjects, but no exposureresponse relationship could be found. Subjects with GSTM1-/GSTT1 genotype had slightly higher frequencies of all effect parameters compared to referents with the same genotype. CONCLUSION: The results indicate slight effects on the peripheral nervous system in tunnel workers related to exposure to N-methylolacrylamide and acrylamide during grouting operations. Apart from a 3 possible delayed axonal effect on sensory fibres in the sural nerve, the effects seemed largely to have been reversible, with normalisation 16 months post exposure. A possible slight change in the ERG suggests subclinical effects on photoreceptors (cones) in the central part of the retina. The pattern of the chromosome results may indicate a possible slight genotoxic effect.

Published
2002

104. Injeksjonsmidler til tetting av vannlekkasjer i anleggsvirksomhet : en vurdering av toksiske stoffer i injeksjonsmidler

Author

Øvrebø, Steinar, Bye, Erik, Kjuus, Helge, Ryberg, David, Thorud, Syvert, and Skaug, Vidar

Subjects
Natriumsilikat, Isocyanater, Natriumalginat, 2-Hydroksyetylmetakrylat, Dimetylaminopropylmetakrylamid, Anleggsarbeid, Tetningsmidler, Hydrogenavsvovlet tung nafta, Akrylamid, Toksisitet, Akrylsyre, N-Metylolakrylamid, Bitumen, Natriumpersulfat, Bygg- og anleggsbransjen
Published
2000

120. Reaction of Glyoxal with 2‘-Deoxyguanosine, 2‘-Deoxyadenosine, 2‘-Deoxycytidine, Cytidine, Thymidine, and Calf Thymus DNA: Identification of DNA Adducts

Author

Olsen, Raymond, primary, Molander, Paal, additional, Øvrebø, Steinar, additional, Ellingsen, Dag G., additional, Thorud, Syvert, additional, Thomassen, Yngvar, additional, Lundanes, Elsa, additional, Greibrokk, Tyge, additional, Backman, Josefin, additional, Sjöholm, Rainer, additional, and Kronberg, Leif, additional

Published
2005
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123. Response

Author

Øvrebø, Steinar, Fjeldstad, Per Einar, Kure, Elin Hegland, Haugen, Aage, and Grzybowska, Ewa

Subjects
Perspectives: Correspondence
Published
1996

135. Modulation of DNA adduct levels in human mononuclear white blood cells and granulocytes by CYP1A1, CYP2D6and GSTM1genetic polymorphisms

Author

Butkiewicz, Dorota, Grzybowska, Ewa, Hemminki, Kari, Øvrebø, Steinar, Haugen, Aage, Motykiewicz, Grażyna, and Chorąży, Mieczysław

Abstract

The CYP1A1, CYP2D6and GSTM1genes encode biotransforming enzymes involved in activation and detoxification of xenobiotics. Metabolically activated chemical compounds may interact with DNA and form adducts. In this study, the effect of the GSTM1, CYP1A1exon 7 and CYP2D6polymorphisms on DNA adduct levels was studied in 170 healthy volunteers. DNA adducts levels were measured by 32P-postlabelling in mononuclear white blood cells (WBC, lymphocytes and monocytes) and granulocytes collected in summer and winter. The influence of the genotype on the level of DNA adducts in both types of WBCs was observed only in summer samples. Individuals with GSTM1deficient (null) genotype had significantly elevated level of adducts in mononuclear WBCs (p=0.045) and granulocytes (p=0.031) compared to GSTM1positives. Higher adduct levels in carriers of combined GSTM1(null)/CYP1A1-Ile/Valgenotype were found in both types of WBCs when compared to GSTM1(+)/CYP1A1-Ile/Ilegenotype carriers (p=0.046 in granulocytes, p=0.092 in mononuclear WBCs). CYP2D6wild-type homozygotes (EMs) and heterozygotes (HEMs) were shown to have significantly higher mononuclear WBC DNA adduct levels than mutant homozygotes (PMs) (p=0.037 and p=0.014). When confounding factors associated with PAH exposure were taken into account a statistically significant effect of CYP1A1exon 7 polymorphism on DNA adduct levels was found (p=0.012 in mononuclear WBCs, p=0.043 in granulocytes). In a subgroup of current smokers (n=95) high DNA adduct levels in granulocytes were associated with GSTM1-(null)genotype, and increased adduct levels in mononuclear WBCs correlated with CYP2D6EM and HEM genotypes. In winter samples the association between the genotype and DNA adduct levels was not observed.

Published
1998
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136. Pyrimidine Metabolism in Acinetobacter calcoaceticus

Author

Øvrebø, Steinar and Kleppe, Kjell

Abstract

The metabolism of thymine, thymidine, uracil, and uridine has been investigated in five different strains of Acinetobacter calcoaceticus. Attempts to isolate thymine and thymidine auxotrophic mutants were not successful. Consistent with this finding was the observation that uptake of radioactive thymine or thymidine could not be demonstrated. Search for enzymes capable of transforming thymine via thymidine to thymidine-5′-monophosphate in crude extracts was performed, and the following enzymes were absent judging from enzyme assays: thymidine phosphorylase (EC 2.4.2.4), trans-N-deoxyribosylase (EC 2.4.2.6), and thymidine kinase (EC 2.7.1.21). The enzymes responsible for the phosphorylation of thymidine-5′-monophosphate to thymidine-5′-triphosphate were present in crude extracts. Radioactive uracil was readily incorporated into both ribonucleic acid and deoxyribonucleic acid, the ratio being 6:1, and radioactivity was found only in pyrimidine bases. No uptake of uridine could be demonstrated. Uridine-5′-monophosphate pyrophosphorylase (EC 2.4.2.9) activity was detected in crude extracts, suggesting that uracil is converted directly to uridine-5′-monophosphate which is then phosphorylated to uridine-5′-triphosphate or transformed to other ribo- and deoxypyrimidine nucleotides.

Published
1973
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140. Neuropathy in grout workers.

Author

Kjuus, Helge, Goffeng, Lars Ole, Heier, Mona Skard, Sjöholm, Hans, Øvrebø, Steinar, Skaug, Vidar, Paulsson, Birgit, Törnqvist, Margareta, and Brudal, Stein

Published
2004

141. Epimerization and stability of two new cis-benzo[a]pyrene tetrols by the use of liquid chromatography-fluorescence and mass spectrometry.

Author

Sagredo C, Olsen R, Greibrokk T, Molander P, and Øvrebø S

Subjects
Animals, Blood Proteins chemistry, Chromatography, Liquid, DNA Adducts chemistry, Hydrolysis, Male, Mass Spectrometry, Molecular Weight, Rats, Rats, Wistar, Spectrometry, Fluorescence, Spectrometry, Mass, Electrospray Ionization, Stereoisomerism, Benzo(a)pyrene analogs & derivatives, Benzo(a)pyrene chemistry
Abstract

Quantitative determination of the hydrolysis products from proteins and DNA gives valuable information regarding the reactive metabolite that forms the protein and DNA adduct. Quantification of protein-benzo[a]pyrene (BP) adducts represents a more sensitive method than quantification of BP-DNA adducts. The aim of the present study was to identify two hydrolysis products from BP-derived protein adducts found in vitro and in vivo in a previous study. Male Wistar rats were injected i.p. with BP, and serum albumin was isolated and subjected to acid hydrolysis at 70 degrees C for 3 h. The hydrolysate was subjected to LC separation, and fractions of the two unknown compounds were collected. The molecular masses of the two unknown compounds were in accordance with being tetrols as judged by LC electrospray mass spectrometry. The fragmentation patterns were characteristic of tetrols with formation of the molecular ion and the loss of water molecules. In addition, the compounds were subjected to acid hydrolysis at 70 degrees C with 0.1 M HCl for 3 h. We observed that two of the known tetrols epimerized to the two unknown tetrols and vice versa. This is probably a characteristic epimerization involving not only position C(10)-OH but also another site like position C(7)-OH. The in vivo findings of the two unknown adducts are probably the result of the formation of BPDE III in the metabolism of BP. These two tetrols must then have the C(7)-OH and C(8)-OH groups in a cis position.

Published
2006
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142. [Diagnosis in metabolic acidosis of unknown origin].

Author

Hovda KE, Hunderi OH, Øvrebø S, and Jacobsen D

Subjects
Acidosis etiology, Acidosis metabolism, Alcoholic Intoxication complications, Alcoholic Intoxication diagnosis, Alcoholic Intoxication metabolism, Diagnosis, Differential, Ethylene Glycols blood, Ethylene Glycols metabolism, Humans, Methanol blood, Methanol metabolism, Osmolar Concentration, Reference Values, Retrospective Studies, Acidosis diagnosis, Ethylene Glycols poisoning, Methanol poisoning
Abstract

Background: Obtaining a precise diagnosis in patients presenting with metabolic acidosis of unknown origin is difficult. Poisoning with methanol or ethylene glycol should be suspected in cases with a combined increase of osmolal and anion gaps., Materials and Methods: Retrospectively we have compared the methanol and ethylene glycol values in poisoned patients with their osmolal gaps. The anion gaps are compared to the toxic anions measured., Results: There were good correlations between serum alcohols and osmolal gaps and between toxic metabolites and anion gaps., Interpretation: The osmolal and the anion gaps are both helpful tools in the diagnosis of patients with metabolic acidosis of unknown origin, especially for identifying patients poisoned with methanol or ethylene glycol.

Published
2004

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