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  • 1
    Electronic Resource
    Electronic Resource
    NMDA-Receptor Antagonist Prevents Measles Virus-induced Neurodegeneration (1991)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 3 (1991), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: N-methyl-d-aspartate (NMDA) receptors represent a major subtype of excitatory amino acid receptors in the mammalian brain. In addition to their physiological role, NMDA receptors have been linked to the occurrence of nerve cell death in several neurodegenerataive diseases. The hamster neurotropic (HNT) strain of measles virus causes non-inflammatory encephalopathy in mice. This is associated with neuronal loss in areas CA1 and CA3 of the hippocampus. Systemic treatment with the non-competitive NMDA receptor antagonist 5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclo-hepten-5,10-imine maleate (MK-801) prevented this cellular necrosis. Thus, a virus may have indirect neurodegenerative effects in the brain due to activation of NMDA receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1991.tb00812.x
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  • 2
    Electronic Resource
    Electronic Resource
    Role of Plasma Membrane Potential in Granulocyte Activation (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 488 (1986), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1986.tb54436.x
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  • 3
    Electronic Resource
    Electronic Resource
    Environmental contaminants and biochemical responses in flatfish from the Hvaler Archipelago in Norway (1991)
    Springer
    Archives of environmental contamination and toxicology 21 (1991), S. 486-496 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract The levels of several environmental contaminants, including selected polyaromatic hydrocarbons (PAH), organochlorines (DDT/DDE, hexachlorobenzene), 15 polychlorinated biphenyl (PCB) congeners, and polychlorinated dibenzofurans and dibenzo-p-dioxins, PCDF/PCDD), and heavy metals (Cd, Hg, Pb, and As) were analyzed in muscle and liver of three different flatfish species (dab,Limanda limanda; flounder,Platichthys flesus; plaice,Pleuronectes platessa) caught by gill netting at different sites in the Hvaler Archipelago. Indices of biochemical effects in liver S9-fractions were studied by measuring cytochrome P450-dependent monooxygenase and UDP-glucuronyl transferase activities, and by immunoquantitating cytochrome P450 1A1 using an indirect enzyme-linked immunosorbent assay (ELISA). Only low levels of PCDD/PCDF, Cd, and Pb were observed, whereas PCB levels were significantly elevated in fish from the inner sites of the Archipelago compared to a reference site. The contaminant gradient toward the Glomma estuary was correlated with increased cytochrome P450 1A1 activity, measured as 7-ethoxyresorufin O-deethylase (EROD), and with immunoquantitated P450 1A1. In contrast, fish from the site at Idefjorden, although containing elevated contaminant levels, did not show elevated EROD activity, but apparently elevated P450 1A1 protein. These findings may reflect different pollution histories of the sites, and indicate the applicability of biochemical effect indices (i.e., EROD and P450 1A1 immunoquantitation) to monitoring studies. The integrated chemical-biochemical approach employed in this study can obviously be expanded to give fruitful information about cause-effect relationships in other contaminant situations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01183869
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  • 4
    Electronic Resource
    Electronic Resource
    Chemoattractant-induced NADPH oxidase activity in human monocytes is terminated without any association of receptor-ligand complex to cytoskeleton (1995)
    Springer
    Inflammation 19 (1995), S. 179-191 
    Details
    ISSN: 1573-2576
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract When the chemotactic peptide formylmethionyl-leucyl-phenylalanine binds to its cell surface receptor, a transmembrane signal is generated that activates the superoxide-producing NADPH oxidase of human phagocytes. Comparing monocytes and neutrophils with regard to the production of superoxide anion induced by the peptide, we found a similar time-course for both types of cells. In neutrophils, ligand binding induced a conversion of the receptor to a high-affinity form, a change suggested to be due to an association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton. This event has been hypothesized to terminate the signal that activates the NADPH oxidase and thereby results in cessation of the cellular production of superoxide anion. Neutrophils preincubated with the cytoskeleton-disrupting drug cytochalasin B showed an increased and prolonged superoxide anion production after activation with the peptide, thus indicating that the cytoskeleton is involved in terminating this response. Formylmethionyl-leucyl-phenylalanine was also found to induce polymerization of actin in monocytes; however, cytochalasin B had no effect on the peptide-induced generation of superoxide anion in these cells. Furthermore, also in monocytes, ligand binding induced a conversion of the receptor to a high-affinity form; however, the receptor-ligand complex did not coisolate with the Triton X-100-insoluble cytoskeleton. These results indicate that, in monocytes, the NADPH oxidase activating pathway is terminated without any association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01534460
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  • 5
    Electronic Resource
    Electronic Resource
    Riochemical and physiological effects in farmed Baltic salmon fed lipids containing xenobiotics extracted from Baltic herring (1993)
    Springer
    Journal of aquatic ecosystem stress and recovery 2 (1993), S. 185-196 
    Details
    ISSN: 1573-5141
    Keywords: aquatic pollutants ; fish ; salmon ; biochemical and physiological effects ; dioxins ; furans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During a 2-year experimental period female baltic salmon (Salmo salar) were fed pellets impregnated with oil extracted from Baltic herring (Clupea harengus). This extract contained lipid-soluble xenobiotics present in Baltic herring, which constitute a major part of the natural diet of Baltic salmon. The fish were examined at the time of ovulation in November each year. After 2 years of feeding, the load of polychlorinated dibenzo-paradioxins and furans in the exposed group was about twice that in the control group, but still low compared with concentrations in feral Baltic salmon. In spite of the relatively low exposure level, several vital biochemical functions were disturbed in the treated fish. Organic skeletal variables were affected indicating that the bone metabolism had been altered. Furthermore, the activities of enzymes involved in steroid biosynthesis were affected, which could lead to disturbances in reproductive functions. Splenocytes from exposed fish sampled in November 1990 showed a reduced mitogenic response, indicating that their immune system was suppressed. Feeding the salmon with pollutant-impregnated pellets also resulted in an induction of the hepatic ethoxyresorufin-O-deethylase (EROD) activity after only 6 weeks of exposure. Likewise, morphological abnormalities, i.e. hypertrophic hepatocytes and various stages of hepatic degeneration, were already apparent after 6 weeks of exposure. However, no EROD induction or morphological responses were recorded at the second and third sampling event, i.e. after one and 2 years of exposure, respectively. this could indicate that some physiological functions may adapt to a restricted xenobiotic load.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047768
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  • 6
    Electronic Resource
    Electronic Resource
    Cytochrome P-450-dependent metabolism in isolated liver cells from fed and starved rainbow trout,Salmo gairdneri (1986)
    Springer
    Fish physiology and biochemistry 1 (1986), S. 105-111 
    Details
    ISSN: 1573-5168
    Keywords: xenobiotic metabolism ; cytochrome P-450 ; isolated liver cells ; starvation ; rainbow trout ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cytochrome P-450 content in liver cells from rainbow trout was not affected by starvation for 12 weeks whereas the rate of cytochrome P-450-dependent deethylation of 7-ethoxycoumarin in liver cells from 6 or 12 weeks starved fish was 60% of the rate in fed fish. Treatment of fish with β-naphthoflavone increased the 7-ethoxycoumarin metabolism several-fold in both starved and fed fish. Optimal cytochrome P-450 monooxygenation in liver cells from fed or starved fish was not affected by addition of glucose or 2-bromooctanoate, an inhibitor of fatty acid β-oxidation which is the main source of metabolic fuel in trout liver. The cellular content of NADPH, an obligatory cofactor for cytochrome P-450 monooxygenation, was not affected by addition of substrate to cytochrome P-450, inhibition of fatty acid β-oxidation or inhibition of the oxidative phosphorylation. This indicates a great capacity of rainbow trout liver cells to retain high NADPH/NADP+ ratios. These results suggest that the cytochrome P-450 mediated metabolism of xenobiotics in liver cells from fed or starved trout is not limited by the availability of reducing equivalents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290210
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  • 7
    Electronic Resource
    Electronic Resource
    Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain (1994)
    Springer
    Fish physiology and biochemistry 13 (1994), S. 335-342 
    Details
    ISSN: 1573-5168
    Keywords: fish ; rainbow trout ; brain ; cytochrome P450 ; CYP1A1 ; induction ; subcellular fractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytochrome P450 (CYP) 1A1 participates in the activation as well as detoxification of environmental pollutants such as aromatic hydrocarbons. This CYP form is also efficiently induced by aromatic hydrocarbons. The presence of CYP 1A1 in the brain might thus be of physiological and toxicological importance. In the present investigation on rainbow trout, the distribution of 7-ethoxyresorufin-O-deethylase (EROD) activity, a cytochrome CYP 1A1 catalyzed reaction, was measured in whole tissue homogenates from brain parts. In control fish, a relatively high activity was found in the rainbow trout olfactory bulb compared to the other brain parts. Although an EROD induction (3 to 7-fold) by β-naphthoflavone (BNF) was recorded in all brain parts from the rainbow trout, the highest induced activity was measured in the olfactory bulbs. To ascertain the distribution of EROD activity in cells, whole brain tissue was subfractionated by differential centrifugation. The fractionation scheme separated mitochondria (P2 fraction) and microsomes (P3 fraction) as determined by marker enzymes and electron microscopy. In control rainbow trout, a low EROD activity could be measured in the P2 fraction. BNF induced the EROD activity in both P2 and P3 fractions. Western blotting showed the induction by BNF of a protein band in the P2 and P3 fractions with a molecular mass around 58,000 when highly specific anti-cod CYP 1A1 antibodies were used. ELISA measurements confirmed the induction of CYP 1A1 protein in the rainbow trout brain subcellular fractions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003438
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  • 8
    Electronic Resource
    Electronic Resource
    Immunochemical cross-reactivity ofβ-naphthoflavone-inducible cytochrome P450 (P450IA) in liver microsomes from different fish species and rat (1991)
    Springer
    Fish physiology and biochemistry 9 (1991), S. 1-13 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P450 ; antibodies ; induction ; β-naphthoflavone (5,6-benzoflavone) ; immunochemistry ; 7-ethoxyresorufin O-deethylase ; fish liver microsomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antibodies prepared against the major β-naphthoflavone (BNF)-inducible cytochrome P450 (P450) forms from three species of fish (rainbow trout, Atlantic cod, and scup) well separated in teleost phylogeny, were used to investigate the immunochemical relatedness of liver microsomal P450 in different species of BNF-treated fish and rat. Rabbit polyclonal IgG against all three P450s and mouse monoclonal antibodies prepared against scup P450E were employed in this study. Liver microsomes were prepared from BNF-treated specimens of hagfish, herring, rainbow trout, cod, scup, perch, plaice and rat. With Western blotting it was shown that the various antibodies cross-reacted with a protein band in liver microsomes in the P450-region of each of the BNF-treated fish species. The apparent molecular weight of the cross-reacting proteins showed differences within the range 54,000–59,000 daltons. The effects of the different antibodies on the microsomal BNF-inducible 7-ethoxyresorufin O-deethylase (EROD) activity gave inhibition patterns that reflected to a certain extent the phylogenetic relationship of the species investigated. In rat microsomes a protein band of relative molecular mass similar to rat P450c (Mr=54,000) was recognized by all antibodies. In addition, a second band of lower molecular mass was strongly recognized by anti-cod P450c antibodies, and faintly stained with anti-rainbow trout P450LM4b IgG and anti-scup P450E MAb 1-12-3. This band could correspond to rat P450d, the isosafrole-inducible rat isoenzyme. Considering the long separate evolutionary history of some of these fishes (50–200 million years), the results demonstrate that certain antigenic epitopes in the BNF-inducible P450 isoenzymes have been strongly conserved during the evolution of fish species. These conserved epitopes seem however not to be directly involved in the measured EROD activities. Furthermore, the results suggest that the BNF-inducible P450s in fish contain regions with structural similarity to the homologous counterpart that has evolved through gene duplication into a P450 family in mammals containing at least two gene products (the P450IA gene family).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01987606
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  • 9
    Electronic Resource
    Electronic Resource
    Regional distribution of microsomal xenobiotic and steroid metabolism in kidney microsomes from rainbow trout (1990)
    Springer
    Fish physiology and biochemistry 8 (1990), S. 141-145 
    Details
    ISSN: 1573-5168
    Keywords: fish ; rainbow trout ; Salmo gairdneri ; kidney ; cytochrome P-450 ; metabolism ; xenobiotics ; steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The regional distribution of microsomal cytochrome P-450-mediated reactions with exogenous and endogenous substrates in the kidney of rainbow trout was studied. The cytochrome P-450-dependent 7-ethoxyresorufin- and 7-ethoxycoumarin-0-deethylase activities were significantly higher (3–4 and 10–14 fold, respectively) in the trunk kidney than in the head kidney, whereas ethylmorphine-N-demethylase activity was evenly distributed along the kidney. The microsomal cytochrome P-450-dependent steroid hydroxylases and steroid reducing enzymes when using androstenedione as substrate also exhibited a regional distribution in trout kidney. The 6β- and 16-hydroxylase activities as well as the 5α-reductase and 17 hydroxysteroid oxidoreductase activities were higher in the anterior part of the trunk kidney than in the head kidney and posterior trunk kidney.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00004441
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  • 10
    Electronic Resource
    Electronic Resource
    Cytochrome P-450 mediated O-dealkylation of 7-alkoxycoumarins in liver microsomes from rainbow trout (Salmo gairdneri) (1989)
    Springer
    Fish physiology and biochemistry 6 (1989), S. 199-205 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P-450 ; β-naphthoflavone ; 7-alkoxycoumarin ; 7-methoxycoumarin ; 7-ethoxycoumarin ; 7-propoxycoumarin ; 7-butoxycoumarin ; fish ; rainbow trout ; liver microsomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evidence has recently been presented for variation in the inducibility of various 7-alkoxycoumarin-O-dealkylase activities in liver microsomes from a number of mammalian species by β-naphthoflavone (βNF). In the present study we have investigated the inducibility of hepatic microsomal 7-methoxycoumarin-O-demethylase, 7-ethoxycoumarin-O-deethylase, 7-propoxycoumarin-O-depropylase and 7-butoxycoumarin-O-debutylase activities in rainbow trout by βNF. O-demethylase activity was increased approximately 17-fold, O-deethylase and O-depropylase activities approximately 9-fold and O-debutylase activity approximately 25-fold. The kinetics of the various hepatic microsomal 7-alkoxycoumarin-O-dealkylase activities were investigated in control and βNF-treated rainbow trout. The O-demethylase-, O-depropylase- and O-debutylase activities exhibited monophasic Michaelis-Menten kinetics in liver microsomes from both control and βNF-treated rainbow trout, whereas the O-deethylase activity exhibited biphasic Michaelis-Menten kinetics in control liver microsomes and monophasic Michaelis-Menten kinetics in liver microsomes from βNF-treated rainbow trout.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01875022
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