Biology subjects

Kleiman, N. J.

Publications and source records attributed to Kleiman, N. J..

2 recordsLinked to original sources

bioRxiv2024

Extending the Acute Skin Response Spectrum to Include the Far-UVC

Guidance on maximal limits for ultraviolet (UV) exposure has been developed by national and international organizations to protect against adverse effects on human skin and eyes. These guidelines consider the risk of both acute effects (i.e. erythema and photokeratitis) and delayed effects (e.g., skin and ocular cancers) when determining exposure limits, and specify the dose a person can safely receive during an 8-hour period without harmful effects. The determination of these exposure limits relies on the action spectra of photobiological responses triggered by UV radiation that quantify the effectiveness of each wavelength at eliciting each of these effects. With growing interest in using far-UVC (200-235 nm) radiation to control the spread of airborne pathogens, recent arguments have emerged about revisiting exposure limits for UV wavelengths. However, the standard erythema action spectra, which provides some of the quantitative basis for these limits, has not been extended below 240 nm. This study assists to expand the erythema action spectrum to far-UVC wavelengths using a hairless albino mice model. We estimate that inducing acute effects on mouse skin with 222 nm radiation requires a dose of 1,162 mJ/cm2, well above the current ACGIH skin exposure limit of 480 mJ/cm2.

biophysics↗

bioRxiv2022

No evidence of induced skin cancer or other skin abnormalities after long term (66 week) chronic exposure to 222-nm far-UVC radiatio

Far-UVC radiation, typically defined as 200-235 nm, has similar or greater anti-microbial efficacy compared to conventional 254-nm germicidal radiation. In addition, biophysical considerations of the interaction of far-UVC with tissue, as well as multiple short-term safety studies in animal models and humans, suggest that far-UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long-term exposure to far-UVC has not been studied. Here, we assessed far-UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH-1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 396 mJ/cm2, 126 mJ/cm2 or 56 mJ/cm2 of 222 nm far-UVC radiation for 66 weeks, 5 days per week, 8 hours per day, as well as similarly-treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths, or incidental skin pathology findings was observed in the far-UVC exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long-term safety of long-term chronic exposure to far-UVC radiation, and therefore its potential suitability as a practical anti-microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings.

cancer biology↗