| 1. |
- Thomsen, JS, et al.
(författare)
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Suppression of spontaneous scratching in hairless rats by sedatives but not by antipruritics
- 2002
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Ingår i: Skin pharmacology and applied skin physiology. - : S. Karger AG. - 1422-2868 .- 1422-2906. ; 15:4, s. 218-224
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Tidskriftsartikel (refereegranskat)abstract
- Experimental scratching in animals has hitherto been provoked by substances injected into the skin or central nervous system. We aimed to investigate if spontaneous scratching in the rat can be reduced by sedatives and antipruritics, and to assess if spontaneous scratching is elicited from the skin or the central nervous system. It may also be a complex behaviour related to the rat species, different from clinical itch. Eight male hairless rats were studied for 6 weeks. The animals were recorded on videotape in the middle of the day and at night, and the scratching activity was counted. The following substances were tested sequentially: midazolam, mepyramine, a eutectic mixture of lignocaine and prilocaine (EMLA«), betamethasone dipropionate and a vehicle. On days 1-3 of each sequence, the test material was applied to a 42-cm2 area on the rostral part of the back. Subsequent treatment of the whole body was made on day 4. Midazolam was injected intraperitoneally from day 1 to day 4. After 4 days of treatment, there was a washout phase of 3 days until the next sequence. We found a positive correlation between minutes awake and number of scratch episodes. Spontaneous scratching was lower after mepyramine on day 4 (p = 0.046) and after midazolam injections on days 1-3 (p = 0.009) and day 4 (p = 0.003). The local anaesthetic, EMLA, did not significantly influence spontaneous scratching. In conclusion, only the drugs with sedative properties suppressed spontaneous scratching, which is probably a cerebral phenomenon or otherwise explained general behaviour, rather than a reaction to skin stimuli. Thus, for testing of topically applied antipruritics, spontaneous scratching cannot be used as an animal model. Furthermore, evaluation of provocative scratching should eliminate/exclude spontaneous scratching.
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| 2. |
- Ahlfors, Stefan, et al.
(författare)
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Reactivity of contact allergenic haptens to amino acid residues in a model carrier peptide, and characterisation of formed peptide-hapten adducts
- 2003
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Ingår i: Skin Pharmacology and Applied Skin Physiology. - : S. Karger AG. - 1422-2868. ; 16:1, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- The type of chemical reaction between hapten and carrier protein in the formation of a complete antigen in vivo giving rise to an allergic contact dermatitis (ACD, type IV allergy) is essentially unknown. About 4,000 low-molecular organic compounds are known to have allergenic properties. ,-Unsaturated carbonyl structures are frequently present among these compounds. Haptens giving rise to antibody formation and type I allergy have been shown to add predominantly to lysine in the carrier protein. In this paper, the reactivity of activated type IV haptens to a model peptide is reported. Essentially all amino acids with nucleophilic properties were present in the model peptide. Investigation of the relative reactivities of the amino acid residues to activated haptens under biomimetic conditions is performed in order to determine the proportions between the adducts of the different amino acid moieties. In all cases, the electrophilic ,-unsaturated haptens were found to be added to the cysteine residue and no lysine adduct was recorded. Nuclear magnetic resonance (NMR) spectroscopy was used to exclude steric hindrance of any amino acid residue in the addition reaction. The hapten-modified peptides were isolated and characterized by NMR and mass spectrometry.
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| 3. |
- Hagstromer, L, et al.
(författare)
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Do urea and sodium chloride together increase the efficacy of moisturisers for atopic dermatitis Skin? A comparative, double-blind and randomised study
- 2001
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Ingår i: Skin pharmacology and applied skin physiology. - : S. Karger AG. - 1422-2868. ; 14:1, s. 27-33
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Tidskriftsartikel (refereegranskat)abstract
- Urea has long been used to treat dry skin. In the present report, we compared two creams, identical with the exception that one contained both urea and sodium chloride and the other urea alone, in 22 patients with atopic dermatitis. Following a 2-week wash-out period, their clinically non-eczematous, rough or normal-appearing skin on the forearms was treated twice daily in a double-blind and randomised manner. We examined the treated areas by measuring transepidermal water loss, capacitance and electrical impedance. Our findings suggest that a moisturiser containing both urea and sodium chloride seems somewhat more effective than the same moisturiser without sodium chloride, at least concerning the ability to reverse impedance indices of atopic skin towards normal, an effect ascribed mainly to changes in hydration of the stratum corneum. However, the clinical significance of our impedance measurements is somewhat premature to decide.
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| 4. |
- Hansson, Christer, et al.
(författare)
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Stereochemical Considerations on Concomitant Allergic Contact Dermatitis to Ester of the CIS-TRANS Isomeric Compounds Maleic Acid and Fumaric Acid.
- 2003
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Ingår i: Skin Pharmacology and Applied Skin Physiology. - : S. Karger AG. - 1422-2868. ; 16:2, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- Allergic contact dermatitis from esters of fumaric acid or esters of maleic acid is rare. The case of a chemist with allergic reactions to esters both of fumaric acid and of maleic acid is presented. Extremely high sensitivity of the patient to diethyl fumarate was noted. The formation of identical complete antigens from esters of these two <i>cis-trans</i> isomeric acids may be an explanation of the patient’s double allergy. This is discussed from a stereochemical point of view. These stereochemical considerations point to a general mechanism where <i>cis-trans</i> isomeric α,β-unsaturated carbonyl compounds are converted into the same complete antigen.
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| 5. |
- Kuzmina, N, et al.
(författare)
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Urea and sodium chloride in moisturisers for skin of the elderly--a comparative, double-blind, randomised study
- 2002
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Ingår i: Skin pharmacology and applied skin physiology. - : S. Karger AG. - 1422-2868. ; 15:3, s. 166-174
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Tidskriftsartikel (refereegranskat)abstract
- Urea has long been used to treat dry skin. In the present report, we compared two identical creams, with the exception that one contained both urea and sodium chloride and the other urea alone, in 23 healthy elderly subjects. Following a 2-week wash-out, their clinically non-eczematous, rough- or normal-appearing skin on the anterior proximal part of the lower legs was treated twice daily in a double-blind and randomised manner. We examined the treated areas by measuring transepidermal water loss, capacitance and electrical impedance. Our findings suggest that both moisturisers seem equally effective, at least concerning the ability to reverse impedance indices towards normal, an effect ascribed to changes in hydration of the stratum corneum. However, the relevance of the impedance parameters to the clinical picture is disputable and further studies of moisturisers in elderly subjects are needed.
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| 6. |
- Norlen, L
(författare)
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Molecular skin barrier models and some central problems for the understanding of skin barrier structure and function
- 2003
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Ingår i: Skin pharmacology and applied skin physiology. - : S. Karger AG. - 1422-2868. ; 16:4, s. 203-211
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Tidskriftsartikel (refereegranskat)abstract
- A better understanding of the structure and function of the human skin barrier is a prerequisite for a more rational design of transdermal drug administration systems. The study of biological structural organisation is, however, confronted with many difficulties, and interpretations of skin barrier-related data should therefore be done with caution. The recently developed ‘single gel-phase model’ constitutes an attempt to interpret structural and functional skin barrier data from a biophysical standpoint.
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| 7. |
- Wallengren, Joanna, et al.
(författare)
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Local skin lesions in the rat after subcutaneous deposition of capsaicin
- 2002
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Ingår i: Skin Pharmacology and Applied Skin Physiology. - : S. Karger AG. - 1422-2868. ; 15:3, s. 154-165
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Tidskriftsartikel (refereegranskat)abstract
- Capsaicin is used to investigate the role of peripheral sensory nerve fibers. In previous studies of rats treated by injection of capsaicin into the skin of the neck, 'spontaneous' lesions in the head and neck region were observed. In this study, the course of development over time, the regional distribution and the innervation of capsaicin-induced dermal lesions were assessed in young male Sprague-Dawley rats. In one experiment, capsaicin was administered subcutaneously by injection in the skin of the neck. In a second experiment, capsaicin was injected in the back by a long needle that tunneled under the skin and allowed the capsaicin to be deposited in the subcutaneous fat of the neck. The density and the distribution of dermal nerve fibers were investigated by immunohistochemistry, using antisera against a panneuronal marker, protein gene product 9.5 (PGP), and calcitonin gene-related peptide (CGRP). In the first experiment, rats developed lesions in the neck area 11 days after injection. In the second experiment, lesions appeared in the skin of the back and occasionally in the neck area 10 days after injection. Development of lesions in the afflicted areas was paralleled by local reduction in the density of CGRP-immunoreactive (IR) nerve fibers, 80% in the first experiment and 72% in the second. The number of PGP-IR fibers was likewise reduced, by 39 and 41%, respectively. The density of the CGRP-IR fibers in the wound area was the same as in the adjacent, nonlesioned skin. The healing of the capsaicin-induced lesions was slow compared with surgical wounds in control animals. The wounds healed with hypertrophic scars. The healing process in the skin of the back was associated with the proliferation of CGRP-IR fibers. The study shows cutaneous lesions to appear in the region of the subcutaneous deposition of capsaicin. A uniform depletion of capsaicin-sensitive nerve fibers in the area of deposition suggests that an additional factor is needed to induce lesions. Possibly, impaired nociception in the afflicted area results in more vigorous grooming behavior and this, in turn, in a local skin damage.
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