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Biomedical subjects

B L Diffey

Publications and source records attributed to B L Diffey.

At least 91 records · Page 5Linked to original sources
PubMed1986

A new technique for xenon-133 ventilation imaging in the diagnosis of pulmonary embolism.

A new approach to ventilation imaging of the lung using 133Xe in patients with suspected pulmonary embolism is described. Three inhalation images are obtained in the postero-anterior, right posterior oblique and left posterior oblique projections, respectively, and each image contains 140-180 kcounts. The technique is quick and simple and needs neither an oxygen supply nor a spirometer. It combines the multiple views characteristic of krypton imaging with the ease of availability of xenon.

Humans↗
PubMed1986

The spectral emissions from ultraviolet radiation lamps used in dermatology.

The spectral power distributions from a wide variety of ultraviolet radiation lamps used for dermatological purposes have been measured using a high-quality spectroradiometer. The data presented here provide a comprehensive compilation of this fundamental (but often hard to come by) characteristic of ultraviolet lamps.

Dermatology↗
PubMed1985

The erythemal response of human skin to ultraviolet radiation.

A reflectance instrument was used to measure objectively the erythemal response of human skin to ultraviolet radiation. Dose-response curves have been constructed for four radiation wavelengths. In each case, the measured increase in erythema was found to be linearly related to the logarithm of the dose of ultraviolet radiation. Significantly different slopes of response were obtained for radiation of 254 and 280 nm compared with 300 and 313 nm radiation. The relevance of these findings is discussed with relation to the mechanism of erythema production and the erythema action spectrum.

Adult↗
PubMed1985

An evaluation of sunscreens in patients with broad action-spectrum photosensitivity.

The photoprotection afforded by three sunscreens available by prescription in the U.K. has been studied in patients with severe broad action-spectrum photosensitivity. All products investigated exhibited high protection against UV-B radiation in accordance with the protection factors quoted by the respective manufacturers. On the other hand, the protection against UV-A ranged only from fair to poor. The need for a sunscreen which has good protection against UV-A is shown to be important for the satisfactory management of patients with severe broad action spectrum photosensitivity.

Chronic Disease↗
PubMed1985

Application of Bayes' theorem to the diagnosis of ankylosing spondylitis from radioisotope bone scans.

The ratio of the uptake of radioactivity in each sacroiliac joint to the uptake in the sacrum has been measured in 57 patients with early ankylosing spondylitis and in 51 control subjects. The distribution of ratios of uptake obtained in each of these two groups shows appreciable overlap, and it is shown that the specification of a 'normal range' in this sort of situation can be misleading in the interpretation of the uptake ratio obtained in a given subject. An alternative approach described here is to use Bayes' theorem, which combines a probability based on the numerical value of the measured ratio with the pretest clinical impression about the likelihood of ankylosing spondylitis to yield a post-test probability of the presence of the disease.

Adolescent↗
PubMed1985

An analysis of plasma levels and 24-hour ECG recordings in tricyclic antidepressant poisoning: implications for management.

Twenty-seven patients with confirmed tricyclic antidepressant (TCA) self-poisoning were studied for 24 h following admission to hospital. Ten patients were judged to be severely poisoned on clinical grounds, whilst 14 patients had initial plasma levels above 1 mg l-1, indicating severe poisoning. Plasma levels were generally maximal on admission to hospital and fell quickly thereafter. Clinical and ECG data showed patients to be most at risk in the casualty department and three patients sustained cardiac arrest. Initial management must be speedy as these patients present with acute toxicity.

Adolescent↗
PubMed1984

A direct comparison between subcutaneous and intralymphatic injections for lymphoscintigraphy.

Lymphoscintigraphy using 99mTc colloids has been proposed as a simple adjunct to lymphangiography. To validate the technique of subcutaneous injection we performed a direct comparison between intralymphatic and subcutaneous administration of 99mTc-antimony colloid. In all cases excellent correspondence was obtained between the two techniques. Lymphoscintigraphy does not provide the same morphological information as lymphangiography, but can provide useful data regarding lymphatic obstruction.

Adult↗
PubMed1984

A portable instrument for quantifying erythema induced by ultraviolet radiation.

The design and performance of an instrument for quantifying ultraviolet-induced cutaneous erythema are discussed. If the instrument is used to record an 'erythema index' at a site on the skin before and after irradiation, the difference between those two readings is essentially related to an increase in vasodilation and is largely independent of the melanin content of the epidermis.

Dermatology↗
PubMed1984

Quantitative studies on cutaneous erythema induced by ultraviolet radiation.

A reflectance instrument was used to measure the variation in UVR-induced erythema at different positions on the back. The pre-irradiation erythema index decreased from top to bottom of the back but the increase in index remained constant for a fixed exposure dose. In contrast, the minimal erythema dose was higher at lower sites on the back. The measured erythemal response increased linearly with the logarithm of the radiation dose from approximately the minimal erythema dose up to at least fifteen times this value.

Adult↗