The New England journal of medicine
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A computerized search of 276 randomly selected cardiology abstracts published in conjunction with three national meetings revealed that 137 abstracts (49.6 per cent) led to full-length articles in peer-reviewed journals within a period of 37 to 43 months. The median interval between publication of the abstract and of the article was 14 months. ⋯ During the observation period, each abstract was cited a mean of 1.6 times in a journal reference list; the number of citations was not significantly higher for abstracts that led to articles than for abstracts that did not. These findings emphasize the preliminary nature of abstracts and suggest restraint in their citation as references.
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Hormone-sensitive adenylate cyclase contains a recently discovered protein component that is required for stimulation of cyclic AMP synthesis by hormones and guanine nucleotides; the component presumably couples the membrane receptor to the cyclase. We studied this protein (termed "N") in erythrocyte membranes of patients with pseudohypoparathyroidism, using assays of the protein's biochemical activity and of its susceptibility to radiolabeling in the presence of [32P]NAD and cholera toxin. ⋯ If activity of the N protein is reduced in other tissues, this deficiency could cause the resistance of target organs in pseudohypoparathyroidism to parathyroid hormone and other hormones that work via cyclic AMP. Erythrocytes of five patients with Type I pseudohypoparathyroidism, all in one family, showed no defect in activity of the N protein; the biochemical defect of this family remains undefined.