Nitroxide has been reported to have antioxidant and some photoprotective properties. Exposure of skin to ultraviolet-A1 (UVA1, 340-400 nm) can lead to formation of reactive oxygen species, reduction in collagen, and increased expression of matrix metalloproteinases (MMPs).
The goal of this research was to determine the effects of 4-hydroxy-Tempo (Tempol), one of nitroxides, in the presence of UVA1 on cytotoxicity, superoxide dismutase enzyme (SOD) activity, lipid peroxidation, and expression of collagen I, collagen III and MMP-1, MMP-3 in human dermal fibroblasts in vitro.
Fibroblasts were irradiated by a single exposure to UVA1 and at the same time incubated with, or without, Tempol and detected twenty-four hours later. SOD activity and lipid peroxidation, as shown by accumulation malonyldialdehyde (MDA), were detected by biochemical assay. Expressions of collagen I, collagen III (protein levels) and MMP-1, MMP-3 (mRNA level) were detected by ELISA and semi-quantitative reverse transcriptase-PCR separately.
Cell survival curve after UVA1 irradiation showed dose dependent decrement pattern and Tempol, between 0.03 and 8 mM, increased cell viability in a dose-effect manner when the cells were exposed to 20 J/cm(2) UVA1. Fifteen Joule per centimetre square of UVA1 significantly inhibited SOD activity and collagen I, collagen III protein levels, while increased MDA level and stimulated MMP-1 and MMP-3 mRNA expression. Tempol reversed these effects caused by UVA1 in some degree or completely and in proper concentration, the results were statistically significant compared with irradiated group.
Tempol had photoprotective properties against UVA1 irradiation in vitro. With antioxidant ability, Tempol inhibited extracellular matrix degradation and preserved collagen production in dermis and may be used as an anti-photoaging agent.
Journal of Dermatological Science 04/2005; 37(3):137-43. DOI:10.1016/j.jdermsci.2004.11.005 · 3.34 Impact Factor
Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases 01/2005; 22(6):478.
To investigate intensity of extremely low frequency magnetic field (ELFMF) emitted from cathode-ray tubes (CRT) of monitors in various directions and to find ways to avoid its influence.
Two hundred CRT monitors and 10 monitors with liquid-crystal display (LCD) were selected. Their ELFMF was detected for three times in front of the monitor at an interval of every 5 cm from 0 cm to 50 cm, as well as at various directions from the monitor.
Intensity of ELFMF significantly attenuated at regular operating position (30 - 40 cm) from 0 cm to 50 cm in front of both 38 cm and 43 cm CRT monitors (P < 0.05). Intensity exceeded 0.4 microT both within 15 cm and 10 cm in front of 38 cm and 43 cm monitors. The highest intensity was found at the upright top position of both kinds of monitors, 9.54 microT for 38 cm monitor and 6.38 microT for 43 cm one, respectively.
It is suggested to keep away from monitor screen as possible when operating a computer, to reduce unnecessary operation in front of a monitor screen, and to shorten operating time. To avoid more hazards from interactive interference between computers, it is necessary to increase distance between monitors.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 02/2004; 38(1):14-7.