Publications by authors named "Jan C van der Leun"

The parties to the Montreal Protocol are informed by three panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of increased UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials.

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The parties to the Montreal Protocol are informed by three panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with UV radiation and its effects on human health, animals, plants, biogeochemistry, air quality and materials. Since 2000, the analyses and interpretation of these effects have included interactions between UV radiation and global climate change.

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After the enthusiastic celebration of the 20th Anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer in 2007, the work for the protection of the ozone layer continues. The Environmental Effects Assessment Panel is one of the three expert panels within the Montreal Protocol. This EEAP deals with the increase of the UV irradiance on the Earth's surface and its effects on human health, animals, plants, biogeochemistry, air quality and materials.

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As part of an inventory of potential interactions between effects of ozone depletion and climate change, a possible effect of ambient temperature on sun-induced skin cancers was suggested. Mouse experiments had shown that increased room temperature enhanced ultraviolet (UV) radiation-induced carcinogenesis; the effective UV dose was increased by 3-7% per degrees C. The present investigation was aimed at studying a possible temperature effect on human skin cancer.

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Recreational tanning, particularly as promoted by commercial salons with 'sunbeds' or booths, has generated increasing attention from the regulatory and the biomedical communities. Several agencies have weighed in with opinions on recommended modifications in guidelines, training procedures, regulatory controls, and consumer awareness. Currently there is little uniformity in the guidance provided by trade groups, in recommendations supplied by health agencies and medical associations, or in regulatory approaches taken or proposed by the many countries involved.

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The complexity of the linkages between ozone depletion, UV-B radiation and climate change has become more apparent.

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The ozone layer.

Photodermatol Photoimmunol Photomed

August 2004

Background/purpose: The intention of this paper is to stimulate the interest for the ozone layer, especially among young colleagues in photobiology; the "layer" is not only important, but also fascinating.

Conclusion: In spite of remarkably effective action, the recovery of the ozone layer will be a long-term process. It will need the attention, also of scientists, for decades to come.

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Studies of UV-induced skin cancers show that malignisation of skin cells, as well as alterations in anti-tumor immune control, are triggered by UV-induced lesions in cellular DNA. Such lesions can probably appear in the human mononuclear leukocytes (lymphocytes) during exposure of skin to sunlight. With the aim of studying the processing of UV-induced DNA lesions in these cells, we used flow cytometry and labelling of their partially denatured nuclei with the monoclonal antibody (H3) that binds cyclobutane pyrimidine dimers in single-stranded DNA.

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Since 1986, people have been informed that they get about 80% of their lifetime ultraviolet (UV) dose by the age of 18. This belief originated from the mathematical conclusion that diligent use of sunscreens (sun protection factor 15 or higher) during the first 18 years of life would reduce the lifetime incidence of nonmelanoma skin cancers by 78%. These data were misconstrued to mean that individuals also got about 80% of their lifetime dose of UV by the age of 18 (linear relationship).

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Solar ultraviolet radiation (UVR) is recognized as a major cause of non-melanoma skin cancer in man. Skin cancer occurs most frequently in the most heavily exposed areas and correlates with degree of outdoor exposure. The incidence of skin cancer is also increased by contact with photosensitizing drugs and chemicals such as psoralens, coal tars and petroleum stocks.

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The potential health effects of elevated levels of ambient UV-B radiation are diverse, and it is difficult to quantify the risks, especially as they are likely to be considerably modified by human behaviour. Nevertheless epidemiological and experimental studies have confirmed that UV radiation is a definite risk factor for certain types of cataract, with peak efficacy in the UV-B waveband. The causal link between squamous cell carcinoma and cumulative solar UV exposure has been well established.

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Depletion of the ozone layer and climate change by the increasing greenhouse effect are distinctly different processes. It is becoming quite clear, however, that the two global environmental problems are interlinked in several ways [D. L.

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Solar ultraviolet (UV) radiation is a prominent environmental carcinogen, but it does not penetrate any deeper than the skin. The UV-related skin cancers are by far the most common form of cancer among white Caucasians in the USA and Australia, and this poses a serious public health problem. Chronic UV exposure of hairless mice is a well established model for squamous cell carcinomas in man.

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