Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-069X
    Keywords: UVB irradiation ; Tanning ; Reactive oxygen species ; Lipid peroxides ; Superoxide dismutase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lipid peroxide levels, the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px), and the development of tanning in the skin of C57 BL/6 mice were assessed for long periods, from very early to late stages, after acute or chronic UVB irradiation. Acute UVB irradiation produced an increase in lipid peroxide levels that peaked 18 h after irradiation, after which the levels declined to a minimum 2–3 days after irradiation and then gradually rose to baseline. Chronic irradiation caused the lipid peroxide level to fall to a minimum at 0.5–1.0 weeks, after which it gradually returned to baseline by the third week. SOD and GSH-Px activities decreased sharply after acute irradiation, reaching a minimum 18 h after irradiation. Following chronic irradiation, these enzyme levels peaked after 0.5 weeks, and thereafter declined gradually to the original levels 3 weeks after irradiation. In contrast, catalase activity did not change significantly. Tanning began to increase at 1.5 weeks after irradiation, with an accelerated rate of increase from the third week. Although UVB has been reported only to decrease or impair reactive oxygen species (ROS) scavenging enzyme activity, we postulate the following from our results: (1) the increase in lipid peroxide levels observed after irradiation was due to UVB-induced ROS; (2) the parallel decrease in enzyme activities may have been due to inactivation by ROS; (3) the decrease in lipid peroxide levels following the peak at 18-h resulted from the scavenging effect of increasing SOD and GSH-Px activities, and (4) the increase in these two enzyme activities was the result of their induction by the increased lipid peroxides or ROS. In addition, these results seem to suggest a possible correlation of melanogenesis with UVB-induced ROS.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-069X
    Keywords: Minocycline ; Subminimal inhibitory concentrations ; Acne ; Neutrophil chemotactic factors ; Neutrophil oxygen metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Comedonal bacteria, Propionibacterium acnes, P. granulosum and coagulase-negative staphylococci (CNS) seem to play an important initiating role in the inflammatory process by producing neutrophil chemotactic factors. The attracted neutrophils, after phagocytosis, release inflammatory factors such as reactive oxygen species (ROS). We investigated the effects of minocycline at subminimal inhibitory concentrations (sub-MIC), i.e. one-tenth MIC, on the production of human neutrophil chemotactic factors in comedonal bacteria, and on several inflammatory parameters of neutrophils, including neutrophil phagocytosis and generation of ROS (O 2 − , H2O2, O $${\text{H}}^{\text{.}} $$ ). ROS generation in a cell-free, xanthinexanthine oxidase system was also assessed. Production of neutrophil chemotactic factors in all strains of P. acnes, P. granulosum and CNS were significantly suppressed by sub-MIC minocycline. Sub-MIC minocycline effectively reduced three kinds of neutrophil-generated ROS (O 2 − , H2O2, O $${\text{H}}^{\text{.}} $$ ). However, neutrophil phagocytosis and the ROS generated in a cell-free system were not markedly changed in the presence of sub-MIC minocycline. The results suggest that sub-MIC minocycline has an anti-inflammatory effect by inhibiting the production of neutrophil chemotactic factors in comedonal bacteria as well as ROS generated by neutrophils in the inflammatory process of acne.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...