Optical coherence tomography (OCT) is a three- dimensional optical imaging technique that can be used to identify areas of early caries formation in dental enamel. The OCT signal at 850 nm back-reflected from sound enamel is attenuated stronger than the signal back-reflected from demineralized regions. To quantify this observation, the OCT signal as a function of depth into the enamel (also known as the A-scan intensity), the histogram of the A-scan intensities and three summary parameters derived from the A-scan are defined and their diagnostic potential compared. A total of 754 OCT A-scans were analyzed. The three summary parameters derived from the A-scans, the OCT attenuation coefficient as well as the mean and standard deviation of the lognormal fit to the histogram of the A-scan ensemble show statistically significant differences (p < 0.01) when comparing parameters from sound enamel and caries. Furthermore, these parameters only show a modest correlation. Based on the area under the curve (AUC) of the receiver operating characteristics (ROC) plot, the OCT attenuation coefficient shows higher discriminatory capacity (AUC=0.98) compared to the parameters derived from the lognormal fit to the histogram of the A-scan. However, direct analysis of the A-scans or the histogram of A-scan intensities using linear support vector machine classification shows diagnostic discrimination (AUC = 0.96) comparable to that achieved using the attenuation coefficient. These findings suggest that either direct analysis of the A-scan, its intensity histogram or the attenuation coefficient derived from the descending slope of the OCT A-scan have high capacity to discriminate between regions of caries and sound enamel.

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Abstract:The role of n-6 polyunsaturated fats upon the formation of the mutagenic DNA adduct malondialdehydedeoxyguanosine (M 1 dG) in blood was investigated in male volunteers (n = 13) who consumed diets high in saturated and polyunsaturated fats, and polyunsaturated fat plus a-tocopherol supplemention (400 IU per day). On day 14 there was a significant difference in adduct levels between diets with saturated fats giving higher levels than polyunsaturated fats but this effect had disappeared by day 20 indicating that there is a relatively rapid adjustment to the effects on DNA damage of changes in dietary fat. a-Tocopherol showed a small benefit by day 20. Five females participated in the PUFA study and had higher mean adduct levels than men but there was no correlation with hormonal status. Overall, PUFA had a limited beneficial effect on M 1 dG levels that warrants further investigation.

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The clinical problems associated with the simultaneous and critical presentation of acute hyperparathyroidism and perforated jejunal ulceration in multiple endocrine adenopathy (MEA type I) require a multidisciplinary approach to management. In the patient described here, the use of cimetidine, a histamine-2 receptor blocker, provided sufficient time after surgical closure of the ulcer to control the hypercalcemic crisis medically and surgically, until the persistent hypergastrinemia could be corrected by sequential excisions of the stomach and pancreaticoduodenal apudomas and hyperplasia. The serum gastrin levels, basal and stimulated (by secretin), provide necessary indications for surgical management of otherwise undetected islet cell pathology. The simultaneously associated pituitary hyperproiactinemia in this patient required both surgical and radiologic therapy.Certain endocrinopathies occur in combination sufficiently frequently in predictable associations to be designated as multiple endocrine adenopathy (MEA) syndromes. 123[2], with medullary carcinoma of the thyroid, adrenal medullary pheochromocytoma(s), and hyperparathyroidism; and MEA type lib [3], with medullary carcinoma of the thyroid, adrenal medullary pheochromocytoma, and mucosal neuromas of the alimentary tract. The endocrinopathies within each of these syndromes usually occur metachronously but, when they occur synchronously, the management of such patients requires multidisciplinary attention to diagnosis and treatment. An example of such a critical clinical condition in a young patient is presented with a critique of the sequential management through the multiple and synchronous endocrinopathies. IncidenceIn MEA type I, the relative incidence of the endocrine components is reported to be hyperparathyroidism in about 90% of cases; pancreatic hypergastrinism, hyperinsulinism, and hyperglucagonism in about 50%; and pituitary abnormalities in about 30% [4]. However, in all probability, the incidence of each is higher. When the endocrinopathies occur metachronously, the first to elucidate symptoms is usually parathyroid in origin, while the pituitary disease is the latest to present clinically. When pancreatic islet abnormalities pre-0364-2313/80/0004-0123 $01.40