No abstract

SUMMARY Rectal potential difference (pd) is directly related to the plasma aldosterone concentration, and rises when aldosterone is stimulated by sodium deprivation. However, when the measurement of rectal pd was tested at a screening test for hyperaldosteronism in 19 hypertensive subjects, four of the eight with primary hyperaldosteronism had a normal pd and four of the eight without aldosterone excess had an abnormally raised potential difference. The technique cannot therefore be recommended as a routine screening test for hyperaldosteronism. No relationship was found between rectal pd and hypertension associated with excess of deoxycorticosterone. Rectal pd rises in response to the mineralocorticoid-like agent carbenoxolone.

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A dewlap is a hanging fold of skin under the throat of oxen and dogs. A similar swelling sometimes occurs in man after radiation therapy. The incidence and natural history of this 'radiation dewlap' has been assessed in patients receiving radiotherapy to malignant growths in the head and neck region. The appearance of this complication has been correlated with the age of the patient, the site and stage of the tumour and the type of radiation employed. The aetiology and significance of the complication are discussed with reference to the anatomy and physiology of the affected tissues and the physical characteristics of the radiotherapy administered. Possible methods of prevention are suggested.

A retrospective study of 305 patients treated with thymoxamine (Opilon) for Ménières disease is described. Thymoxamine controlled symptoms in 78.7% of patients and the time to maximum improvement ranged from six weeks to three months. Seven patients suffered side-effects.