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  • 1
    ISSN: 1432-069X
    Keywords: Hyperpigmentation ; UVB ; UVA ; Allergic contact dermatitis ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In moderately colored guinea-pig skin, UVB, PUVA, and allergic contact dermatitis were shown to induce hyperpigmentation that resembled the pigmentary changes observed in mongoloid human skin. Using this model, we examined the effects of chemical agents, including tyrosinase inhibitors and sunscreen agents, on the color changes induced by UV irradiation. The daily exposure of brownish guinea-pig skin to UVB irradiation at a variety of energies for 3 successive days induced clearly visible black pigmentation on the irradiated rectangular areas of the flank within a few days of irradiation, the maximum being reached about 1 week after irradiation, i.e., similar to the changes that occur in pigmented human skin. Split epidermal sheets prepared from untreated pigmented guinea pigs exhibited 200–400 melanocytes/mm2; 1 week after UV irradiation, the applied areas show an increased number of strongly dopa-positive melanocytes with stout dendrites (800–1,000 cells/mm2). UVA irradiation following an intraperitoneal injection of 8-methoxypsoralen (8-MOP) also produced black pigmentation 1 week after irradiation, and this was paralleled by a marked increase in the number of dopa-positive melanocytes in dopa-reacted split epidermal sheets. Allergic contact dermatitis produced by the application of 1-phenylazo-2-naphtol induced hyperpigmentation after an interval of about 14 days in 10 of the 21 allergy-acquiring animals examined. This induced pigmentation was accompanied by an increase in the number of dopa-positive melanocytes as compared to the number seen in controls. In contrast, allergic contact dermatitis produced by the application of dinitrochlorobenzene failed to induce such a high ratio of postpigmentation, with only 3 of the 21 allergy-acquiring animals showing hyperpigmentation and 5 showing depigmentation; in the latter, there was a slight decrease in the number of dopa-positive melanocytes. To study the preventive effect of tyrosine inhibitors on UVB-induced pigmentation, daily topical applications of these compounds were performed after three daily UVB irradiations. Treatment with 10% hydroquinone for 10 days interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to the number found in UVB-irradiated, untreated control skin.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 13 (1991), S. 89-104 
    ISSN: 1279-8517
    Keywords: Gallbladder ; Lymphatic system ; Carcinoma ; Macroscopic anatomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé A partir de la dissection fine des lymphatiques de la vésicule effectuée sur 4 sujets adultes, trois voies de drainages ont pu être schématisées. 1) La voie cholécysto-rétro pancréatique qui peut être considérée comme la principale, comporte deux trajets, l'un descendant en spirale de la face antérieure de la voie biliaire principale vers son bord postéro-droit, et l'autre descendant directement à la face postérieure du conduit biliaire. Dans leur segment rétroportal, ces voies convergent vers un important nœud lymphatique qui apparaît comme le principal nœud terminal de cette voie. Nous l'avons dénommé le nœud principal rétroportal. 2) La voie cholécysto-cœliaque est utilisée par quelques lymphatiques de la vésicule biliaire qui se dirigent vers la gauche à travers le ligament hépato-duodénal pour rejoindre les nœuds cœliaques. 3) La voie cholécysto-mésentérique est empruntée par des lymphatiques qui descendent vers la gauche en avant de la veine porte et rejoignant les nœuds situés à l'origine de l'artère mésentérique supérieure. Ces trois voies convergent vers les nœuds lymphatiques abdomino-aortiques situés à proximité de la veine rénale gauche; les nœuds situés dans l'espace inter-aortico-cave seront particulièrement importants.
    Notes: Summary Based upon the detailed dissections of the lymphatic system of four adult cadavers, the lymphatic drainage of the gallbladder was divided into three pathways. 1) The cholecysto-retropancreatic pathway, which can be regarded as the main pathway, had two routes, one running spirally and posteriorly from the anterior surface of the common bile duct to the right, and the other running almost straight down from the posterior surface of the common bile duct. At the retroportal segment, these routes converged at a large lymph node, which appeared critical as the main terminal lymph node of this pathway. We designated this node the principal retroportal node. 2) The cholecysto-celiac pathway was the route by which some of the lymphatics from the gallbladder ran to the left through the hepatoduodenal ligament to reach the celiac nodes. 3) The cholecysto-mesenteric pathway was the route by which some of the lymphatics ran to the left in front of the portal vein and connected with the nodes at the superior mesenteric root. These three pathways converged with the abdomino-aortic lymph nodes near the left renal vein; in particular, the nodes in the interaortico-caval space were considered important.
    Type of Medium: Electronic Resource
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