No abstract

No abstract

Parathyroidectomy was carried out in 26 patients over a 14-yΕar period. Excellent results were obtained in patients with severe hyperparathyroidism. Vascular calcification, hypercalcaemia and pruritus did not justify surgery unless associated with unequivocal hyperparathyroidism. 13 patients required intravenous calcium infusion for up to 2 weeks to control post-operative hypocalcaemia. Calcium requirements could be predicted from the pre-operative plasma alkaline phosphatase level. Following operation continued treatment with vitamin D was necessary to prevent hypocalcaemia. Hyperparathyroidism recurred in 1 patient after 8 years and 4 patients developed osteomalacia. Since parathyroid hormone may have toxic effects other than those on bone, maintenance of normal levels should be a long-term objective in the treatment of patients with chronic renal failure. Where large parathyroid glands are present, surgical reduction in gland mass is a logical prelude to long-term suppression of parathyroid hormone with vitamin D and phosphate-binding agents.

Summary A state of potassium tolerance has been produced in rats by the administration of a high potassium diet. Tolerant rats had an increased survival when subjected to continued potassium loads and an enhanced ability to excrete potassium. Tolerant animals also had a lower plasma potassium concentration than controls when subjected to similar potassium loads. Increased urinary1excretion of potassium in tolerant animals was not dependent on sodium excretion but was accompanied by a reduced stool sodium/potassium ratio, suggesting increased mineralocorticoid activity. Nephrectomised tolerant rats showed no significant difference in plasma potassium concentration after an acute load when compared to control animals and an extra‐renal mechanism for tolerance was not confirmed. Potassium tolerance in the rat can be adequately explained by an enhanced ability to excrete potassium in the urine, and this mechanism appears to be well suited to the physiological adaptation to high potassium intake under natural conditions.