Assignment of islet cell antibody titres and selection of subjects for IDDM prevention trials.
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Biomedical subjects
Publications and source records attributed to A De Leiva.
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We have analysed the sex difference of calcitonin (CT) levels after combined stimulation with calcium and pentagastrin (Ca-PG) in the normal population, and the relationship of the post-stimulatory CT levels with free testosterone (FT). We have also studied the correlation between CT values and the anthropometric parameters, body mass index (BMI) and body surface area (BS), as well as the relationship between CT levels and calcium. A positive and statistically significant correlation was found between post-stimulatory CT and the increment over the base-line of CT and basal FT, and with the anthropometric parameters. However, the increment of CT and the peak values of CT did not have any significant correlation with the Ca levels (basal or post-stimulation). We conclude that the enhanced CT response found in normal men compared to normal women is at least partially determined by the higher testosterone levels found among normal men.
The main source of circulating immunoreactive somatostatin (IRS) seems to be the gastrointestinal tract. We therefore investigated plasma IRS in patients with various gastrointestinal diseases. Mean basal IRS oscillated between 46 and 73 pg/ml. A postprandial rise was observed in all patients and age-matched controls. However, the increment was significantly higher in patients with duodenal ulcer (159 +/- 20 pg/ml), active ulcerative colitis (176 +/- 17 pg/ml), and irritable bowel syndrome (194.4 +/- 20.4 pg/ml). Patients with duodenal ulcers who underwent vagotomy showed a decreased postprandial increment (107 +/- 10 pg/ml) when compared with active duodenal ulcer patients. No difference was demonstrable between controls and individuals with gastric ulcer, and patients with inactive ulcerative colitis. These results suggest that vagal innervation plays a role in postprandial IRS stimulation, whereas gastric hyperacidity, acute lesions of the colonic mucosa, and hypermotility of the gastrointestinal tract are associated with an exaggerated postprandial IRS response. Since somatostatin is known to influence many gastrointestinal functions, these variations in circulating IRS concentrations may be of pathophysiologic importance.