Ultraviolet (UV) irradiation is a major environmental carcinogen involved in the development of skin cancer. To elucidate the initial signaling during UV-induced damage in human keratinocytes, we investigated lysosomal exocytosis and apoptosis induction. UVA, but not UVB, induced plasma membrane damage, which was repaired by Ca(2+)-dependent lysosomal exocytosis. The lysosomal exocytosis result...

High-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with ultraviolet absorbance (UVA) and on-line dissolved organic carbon (DOC) detectors has been adapted and optimized under various conditions. An enhanced HPSEC-UVA system employing a modified commercially available DOC detector provides a better understanding of the qualitative and quantitative natural organic m...

Although the biological importance of ultraviolet light (UVR) attenuation has been recognised in marine and freshwater environments, it is not generally considered in in vitro ecotoxicological studies using algal cell suspensions. In this study, UVA and UVB extinction were determined for cultures of algae with varying cell densities, and the data were used to calculate the corresponding extinct...

UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm; 100 nm has been chosen arbitrarily as the boundary between nonionizing and ionizing radiation. UV radiation is conventionally categorized into 3 regions: UVA (>315–400 nm), UVB (>280–315 nm) and UVC (>100–280 nm) (Figure 1). These categories have been confirmed by the Commission I...

We evaluated nine semi-transparent plastic window-tinting films for their ability to block ultraviolet A (UVA) and infrared (IR) radiation and transmit therapeutic blue light (400-520 nm) for treating jaundiced newborns. For indoor testing, three light sources (TL/52 special blue fluorescent, Black Light UVA and IR heat lamps) were positioned above each film and measured successively using a th...

UVA irradiation plays a role in premature aging of the skin through triggering oxidative stress-associated stimulation of matrix metalloproteinase-1 (MMP-1) responsible for collagen degradation, a hallmark of photoaged skin. Compounds that can activate nuclear factor E2-related factor 2 (Nrf2), a transcription factor regulating antioxidant gene expression, should therefore serve as effective an...

Many materials in everyday use such as window glass in homes and offices, glass in sunrooms and greenhouses, vehicle glass and some brands of sunscreens act as a barrier to the shorter UVB wavelengths while transmitting some of the longer UVA wavelengths. This paper reports on the erythemal exposures due to the UVA waveband encountered over a 12-month period for a solar zenith angle (SZA) range...

This article reviews the developments of 4⁃thiothymidine analogues, assisted with UVA light, as a novel cancer therapy. First, the key points on synthetic chemistry, photochemistry and cellular toxicity of 4⁃ thiothymidine are summarized. As the chemical structure of 4⁃thiothymidine is very similar to that of its parent thymidine, thus 4⁃thiothymidine can be readily incorporated into cellular D...

A. Environmental factors 1. Non-Ionizing Radiation – Ultraviolet (UVA & UVB) Two wavelength “types” of UV reach the earth’s surface – UVA (320-400nm) and UVB (290-320nm). Most of the UVB and all UVC are filtered by stratospheric ozone. UVA was initially thought to be noncarcinogenic, but is now thought to be a potent co-carcinogen with UVB. Recently, high dose UVA (as found in tanning beds) has...

Exposure to solar UVA (320-400 nm) radiation can damage DNA and lead to skin disorders. Conventional dosimetry using a single piece of polysulfone or diglycol carbonate (CR-39) cannot provide accurate measurement of the biologically effective irradiance for erythema for the UVA waveband. A package employing four dosimeters (polysulfone, nalidixic acid, 8-methoxypsoralen and phenothiazine) has b...