Biomedical subjects
B L Diffey
Publications and source records attributed to B L Diffey.
The risk of skin cancer from occupational exposure to ultraviolet radiation in hospitals.
The risk of skin cancer in subjects who are occupationally exposed to ultraviolet radiation (UVR) in hospital phototherapy departments has been estimated using a mathematical model based on age and annual UVR exposure. Measurements have shown that the median UV dose received by staff during an 8 h working day is one-fifth of the recommended maximum permissible exposure. This level of exposure increases the risk of skin cancer during a working life of 40 years by about 25% compared with non-exposed workers. Comparison with ionising radiation workers in hospitals indicates that the risk of death from an occupationally induced cancer is about 30-50 times less in UV workers.
The time course of UVB and UVC erythema.
The time course of ultraviolet erythema was measured using six different exposure doses of UVC and UVB radiation in each of eight adult subjects. The intensity of erythema was measured by reflectance spectrophotometry at 4, 8, 24, 36, and 48 h after irradiation. In five subjects there was no significant difference between the form of the UVB and UVC erythema time-course. In three subjects a significant difference was observed, but this was random rather than systematic between subjects. The results do not confirm the previously reported major differences in time course between the two qualities of radiation.
UVB and UVC, but not UVA, potently induce the appearance of T6-, DR+ antigen-presenting cells in human epidermis.
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The action spectrum in quinine photosensitivity.
The action spectrum for 24-h ultraviolet erythema was determined in three elderly patients who presented with a photosensitive eruption and who were taking quinine sulphate for night cramps. In each case the in vivo action spectrum was consistent with the absorption spectrum of quinine, and extended from about 370 nm to at least the lower wavelength limit of terrestrial sunlight (approximately 300 nm). Calculations based upon the combination of the action spectrum for quinine photosensitivity, the spectrum of terrestrial sunlight, and the transmission properties of various topical sunscreens, indicated that a broad absorption spectrum sunscreen would be required to provide adequate photoprotection.
The suitability of sunglasses worn by PUVA patients.
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Naproxen pseudoporphyria in a patient with vitiligo.
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The action spectrum in drug induced photosensitivity.
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Augmentation of ultraviolet erythema by indomethacin in actinic prurigo: evidence of mechanism of photosensitivity.
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The colour of light for neonatal phototherapy.
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Light and length of stay in hospital.
A study was carried out to examine whether the time spent as an inpatient in hospital showed a seasonal dependence which could be attributed to differences in ambient lighting levels between summer and winter. It was found that the season of admission to hospital did not make any appreciable difference to how long patients took to recover before they were discharged.
Treatment of solar urticaria with terfenadine.
Treatment with the H1 receptor antagonist terfenadine increased significantly the dose of radiation required for weal and flare formation in 5 patients with idiopathic solar urticaria. The dose of radiation required to produce immediate erythema localised to the irradiation site was unchanged by terfenadine. The weal and flare reaction in solar urticaria, but not the immediate erythema, is mediated by histamine acting on the H1 receptor.
Ambient ultraviolet radiation and skin cancer incidence.
Environmental ultraviolet radiation (UVR) was monitored for one year at Durham (latitude 55 degrees N) using a stationary, horizontal sensor, and a sensor rotating in a vertical plane designed to simulate the random motion of subjects outdoors. From these data it was possible to calculate the personal solar UVR representative of populations living at different geographical locations and experiencing varying patterns of cloud cover. The conclusion was that present monitoring programmes that record ambient solar UVR in a horizontal plane at different locations as input data to studies on the epidemiology of skin cancer are appropriate for obtaining a relative estimate of the population exposure in locations with different climatic conditions, providing, of course, that the outdoor exposure habits of different populations are comparable.
[Is accurate UVA dosimetry in photobiology and photodermatology an illusion?].
Accurate UVA dosimetry is of primary importance for photobiological research as well as for UVA phototherapy and photochemotherapy. For the former, it is necessary because the success or failure of an experiment can depend on the UVA dose, and for the latter, the carcinogenic risks are dependent upon the cumulative dosage, as is the evaluation of the therapy. Experience has shown that the UVA meters used in different photodermatological and photobiological centers give divergent values when exposed to the same UVA source. One Joule/cm2 does not seem to be the same thing everywhere, and it can vary by as much as 400 p. 100.
Phototherapy and dithranol treatment of psoriasis: new lamps for old.
The response of psoriasis to ultraviolet radiation and dithranol was compared with the response to dithranol alone in 24 patients. The difference in rate of response, measured as change in plaque thickness, and the difference in time to complete clearance of psoriasis between irradiated and non-irradiated forearm lesions was significantly greater for patients treated using fluorescent lamps with negligible ultraviolet C emission (Wolff Helarium) than for those patients treated with a medium pressure mercury arc lamp (p less than 0.01) or an array of fluorescent sunlamps (p less than 0.05). The difference in therapeutic response shows that ultraviolet B phototherapy is effective when used in combination with dithranol. Nevertheless, radiation sources with substantial ultraviolet C emission, such as the medium pressure mercury arc lamp most commonly used to treat psoriasis in the United Kingdom, have little effect because delivery of therapeutic doses of ultraviolet B is limited by erythema induced by ultraviolet C.
An appraisal of ultraviolet lamps used for the phototherapy of psoriasis.
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Quantitative studies on UVA-induced erythema in human skin.
The erythemal response of normal human skin to UVA and UVB radiation was measured objectively using a reflectance instrument in seven subjects, and a laser Doppler velocimeter in two subjects. UVA radiation was produced using a newly-developed high-intensity UVA lamp. The slope of the log dose-erythemal response curve for UVA at 24 h after irradiation was found not to differ significantly from that for UVB. The time course of UVA erythema was biphasic; erythema was present immediately after irradiation, fell to a minimum at about 4 h and then rose to a broad plateau between 6 and 24 h. The intensity of the early phase was dose-rate dependent, whereas that in the later phase depended on dose only.
Photodermatitis due to spot welding.
The case of a patient with a 1-year history of recurrent, severe facial dermatitis is reported. The role of ultraviolet radiation from arc welding or other equipment at work in inducing dermatitis is discussed.