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Biomedical subjects

B L Diffey

Publications and source records attributed to B L Diffey.

At least 199 records · Page 11Linked to original sources

Response of plasma-25-hydroxyvitamin D to ultraviolet irradiation in long-stay geriatric patients.

The response of plasma-25-hydroxyvitamin D (25[OH]D) to different exposures to ultraviolet irradiation has been studied in patients in long-stay geriatric wards. Increases sufficient to bring the plasma-25(OH)D into the normal range may be obtained with doses less than those required to produce erythema. The provision of such background irradiation may be a suitable method of preventing vitamin-D deficiency in elderly subjects who receive very little exposure to sunlight.

Age Factors↗

A new dosemeter for the measurement of natural ultraviolet radiation in the study of photodermatoses and drug photosensitivity.

The production and optical properties of a dosemeter for natural ultraviolet radiation are descirbed. The physical form of the dosemeter is a thin polymer film which incorporates 8-methoxypsoralen as the chromophore. The dosemeter responds to ultraviolet radiation at wavelengths up to 380 nm and is suitable for quantifying the UV exposure of patients suffering from some idiopathic photodermatoses or drug photosensitivity.

Film Dosimetry↗

Description and application of a personal ultraviolet dosimeter: a review of preliminary studies.

Preliminary work on a dosimeter suitable for measuring UVR exposure on individual persons is described. It is based on the use of polysulfone film which, on exposure, shows a change in absorbance that is determined spectrophotometrically. The results of studies of groups of persons with vastly different degrees of solar exposure, e.g., outdoor and indoor workers and geriatric patients, and psychiatric patients with photosensitivity from phenothiazine drugs are presented. We consider the dosimeter may also be suitable for epidemiologic studies in sunlight-induced skin cancer.

Antipsychotic Agents↗

The anatomical distribution of sunlight.

The relative distribution of natural ultraviolet radiation has been measured at ten sites on the surface of an unclothed manikin for 2 h around solar noon on 19 different days during late summer in Canterbury, U.K. The dosimeter used was polysulphone film. The results obtained indicate that vertical surfaces of the body receive about one half of the dose relative to the vertex and that the relative doses at different sites are independent of weather conditions.

Body Surface Area↗

Problems associated with ultraviolet dosimetry in the photochemotherapy of psoriasis.

A hypothetical action spectrum for the regression of lesions in photochemotherapy of psoriasis is proposed. An ideal detector should have a wavelength response which matches this action spectrum but this is generally not the case with commercially available photometers. The problems that may arise by indiscriminate use of such detectors are discussed, together with a suggested solution.

Humans↗

A dosimeter for long wave ultraviolet radiation.

A polymer film, which incorporates phenothiazine as the chromophore, has been developed as a personnel dosimeter for long wave ultraviolet radiation. It is stable, reproducible and is particularly suited to monitoring the doses received by patients undergoing photochemotherapy for psoriasis.

Dose-Response Relationship, Radiation↗