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  • 1990-1994  (4)
  • 1960-1964
  • 1940-1944
  • 1930-1934
  • 1915-1919
  • 1880-1889
  • Inflammation  (2)
  • Prohapten activation  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Are free radicals and not quinones the haptenic species derived from urushiols and other contact allergenic mono- and dihydric alkylbenzenes? The significance of NADH, glutathione, and redox cycling in the skin (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 56-64 
    Details
    ISSN: 1432-069X
    Keywords: Allergic contact dermatitis ; Monohydric alkylbenzenes ; Dihydric alkylbenzenes ; Quinols ; Resorcinols ; Catechols ; Urushiols ; Prohapten activation ; NADH ; Cysteine ; Glutathione ; Diphenylpicrylhydrazyl ; 2-Oxo-4-thiazolidine carboxylate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The induction of allergic contact dermatitis to urushiols from poison ivy and related plants is generally believed to involve an initial oxidation event by which a protein-reactive quinone is formed. However, this does not readily account for the contact allergenicity of closely related mono- and dihydric alkylbenzenes such as the alkylphenols and alkylresorcinols which are not so easily oxidised to quinones in vitro. When the redox processes known to occur in living tissues are taken into consideration, a more plausible unifying mechanism involving the formation of protein-reactive radical species becomes apparent. Experiments described here examine the autoxidation of p-benzoquinone and various mono- and dihydric benzenes and alkylbenzenes, and their reactions with the diphenylpicrylhydrazyl radical, cysteine, glutathione, and NADH. We have also demonstrated that administration to mice of 2-oxo-4-thiazolidine carboxylate, a compound known to elevate intracellular glutathione levels, inhibits the irritancy and sensitising activity of 3-pentadecylphenol. This work suggests that redox cycling in the skin following penetration of allergenic mono- and dihydric alkylbenzenes initially depletes local levels of endogenous reducing equivalents such as glutathione and NADH; once depleted, further cycling results in the uncontrolled generation of radical species which may reasonably be expected to exhibit protein reactivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505646
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Biochemical responses of skin to allergenic and non-allergenic nitrohalobenzenes (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 400-408 
    Details
    ISSN: 1432-069X
    Keywords: Allergic contact dermatitis ; Dinitrohalobenzenes ; Picryl chloride ; Prohapten activation ; Xenobiotic metabolism ; Glutathione status ; Oxidative stress ; NADPH-dependent reductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using a selection of ‘classic’ haptens (dinitrohalobenzenes and picryl chloride) and related nonsensitizing analogous, we examined changes in levels of glutathione (GSH) and glutathione disulphide (GSSG) in mouse skin 12 h after their epicutaneous application. We observed that elevation of GSSG levels and/or depletion of GSH levels correlated well with contact allergenic potential. Non-sensitizing analogous failed to perturb GSH/GSSG status. In vitro assays using mouse skin and rat liver microsomal preparations indicated that only the allergenic nitrohalobenzenes initiated NADPH-dependent oxygen utilization, with the activity falling off in the order picryl chloride ≫ DNIB 〉 DNBB 〉 DNCB 〉 DNFB. In addition, an examination of the colour of mouse skin homogenates ex vivo after application of the dinitrohalobenzenes showed significant yellowing (consistent with aromatic nucleophilic substitution) only with DNFB. Our results indicate that, while an aromatic nucleophilic substitution reaction with skin protein can possibly account for the allergenicity of DNFB, it does not seem to occur with DNCB, DNBB or DNIB. These may instead behave mainly as prohaptens which are activated enzymically by NADPH-dependent reductase (s) within the skin, with the concomitant generation of superoxide and hydrogen peroxide, to form potentially protein-reactive free radical and other metabolites. Picryl chloride appears capable of both conjugating directly with proteins by aromatic nucleophilic substitution and undergoing NADPH-dependent metabolism to other potentially protein-reactive metabolites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372070
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Changes in extracellular potassium concentration in cat spinal cord in response to innocuous and noxious stimulation of legs with healthy and inflamed knee joints (1990)
    Springer
    Experimental brain research 79 (1990), S. 283-292 
    Details
    ISSN: 1432-1106
    Keywords: [K+]0 Spinal cord ; Posterior articular nerve ; Knee joint ; Inflammation ; Pain ; Arthritis ; Nociception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 20 cats anaesthetized with alpha-chloralose and spinalized at the thoracolumbar junction we investigated the role of stimulation induced accumulation of extracellular potassium in the spinal cord in the processing of nociceptive discharges from the knee joint. For that we electrically stimulated the posterior articular nerve of the knee. We further performed innocuous and noxious stimulation of the knee and of other parts of the leg and studied the effect of an acute inflammation of the knee on [K+]0 in the spinal cord. Innocuous stimulation of the skin (brushing or touching) and innocuous movements in the knee joint all induced rises in [K+]0 which were maximal at recording depths of 1500 to 2200 μm below the surface of the cord dorsum. Peak increases were 0.4 mM for touching the leg and 1.7 mM during rhythmic flexion/ extension of the knee joint. Noxious stimulation of the skin, the paw, the tendon and noxious movements of the knee joint also produced rises in [K+]0, which were somewhat larger for the individual types of stimuli than those produced by innocuous intensities. Electrical stimulation of the posterior articular nerve induced rises in [K+]0 by up to 0.6 mM. Stimulus intensities sufficient to activate unmyelinated group IV fibers were only slightly effective in raising [K+]0 above the levels reached during stimulation of myelinated group II and III fibers. During development of an acute inflammation of the knee joint (induced by kaolin and carrageenan), increases in [K+]0 and associated field potentials became larger by about 25%. We assume that this reflects an increase in neuronal responses. In conclusion, changes in [K+]0 in the spinal cord are some-what larger during noxious stimulation than during innocuous stimulation. The absolute level reached depended more on the site and type of stimulation than on the actual stimulus intensity itself. Hence a critical role of spinal K+ accumulation for nociception is unlikely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608237
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Tonic descending inhibition of spinal cord neurones driven by joint afferents in normal cats and in cats with an inflamed knee joint (1991)
    Springer
    Experimental brain research 83 (1991), S. 675-678 
    Details
    ISSN: 1432-1106
    Keywords: Pain ; Inflammation ; Descending inhibition ; Nociception ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In ten cats, single unit electrical activity was recorded in the lumbosacral spinal cord from neurones driven by stimulation of afferent fibres from the ipsilateral knee joint. Tonic descending inhibition (TDI) on the responses of these cells was measured as increases in resting and evoked activity of the neurones following reversible spinalization of the animals with a cold block at upper lumbar level. Acute inflammation of the knee joint was induced in five of the cats by the injection of kaolin and carrageenan into the joint. TDI was observed in 25 of 33 neurones recorded in normal animals (76%) and in 36 of 40 (90%) neurones recorded in animals with acute knee joint inflammation. In both kinds of preparation TDI was more pronounced in neurones recorded in the deep dorsal horn and in the ventral horn than in those recorded in the superficial dorsal horn. There was a tendency in the whole sample for TDI to be greater in neurones with input from inflamed knees. We conclude that the spinal processing of afferent information from joints is under tonic descending influences and that the amount of TDI can be altered during acute arthritis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229846
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    Paper (German National Licenses)
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