Clinical science
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1. The distribution of intact parathyroid hormone-(1-84) [PTH-(1-84)] and of its COOH-terminal fragments was determined in human serum by column chromatography. In addition to PTH-(1-84) (peak I), COOH-terminal fragments having molecular weights of approximately 4000-7000 (peak II) and immunoreactive components co-eluting with human PTH-(1-12) (peak III) were observed. 2. ⋯ In chronic renal failure as well as in a group of patients with vitamin D deficiency, pseudohypoparathyroidism and primary hyperparathyroidism and in controls, significant linear relations were found between the serum concentrations of calcium and log (peak II/peak I). Our findings suggest that the conversion of intact PTH-(1-84) into COOH-terminal fragments by the parathyroid glands (resulting in a raised secretion of fragments) and/or in peripheral organs may be directly related to the serum concentration of calcium. However, the degradation of the fragments may also be suppressed in a calcium-dependent manner.
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1. Twenty lightly anaesthetized dogs were cooled to 29 degrees C by cold-water immersion. Ventilation was spontaneous and the animals were allowed to shiver freely. ⋯ The group rewarmed in hot water achieved normal core temperature most rapidly but there was no difference in the rewarming rates of the group rewarmed spontaneously and of the group given warm air to breathe in addition. 4. The group given a muscle relaxant and rewarmed with warm inspired air required 12 h to achieve the same core temperature as the shivering groups achieved in 2 h. Compared with the heat produced by shivering the amount of heat which it was possible to transfer across the respiratory tract was so small that it did not materially influence the rate of rewarming.