Contrast-enhanced magnetic resonance imaging of regional cerebral hemodynamics is discussed. Techniques for measuring cerebral blood volume (CBV) have been validated in animal models and have recently been applied to human studies. Factors affecting CBV measurement in pathologic tissue are addressed. Extension of these techniques to the measurement of cerebral blood flow is presented.

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Cerebral blood flow was quantitatively mapped by monitoring the cerebral washout of H2(17)O using rapid, single-shot proton NMR imaging. H2(17)O acts as a freely diffusible contrast agent for proton imaging via its scalar-coupled term, enhancing T2 relaxation. Measured values for CBF ranged from 29 to 106 ml/min/100 g over a range of arterial pCO2 between 23 and 81 Torr.

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The effect of xylitol and glucose on the rate of gastric emptying and intestinal transit and on motilin, gastric inhibitory polypeptide (GIP), and insulin release were studied in human volunteers. A single oral dose of 200 mL water containing 30 g glucose or 30 g xylitol, mixed with a 99mtechnetium-tin (99mTc-Sn) colloid, was used. Similar dosing without the label was used in motilin, GIP, and insulin studies. Xylitol decreased the rate of gastric emptying but concomitantly accelerated intestinal transit compared with glucose. The half-times for gastric emptying were 77.5 +/- 4.6 and 39.8 +/- 3.4 min after ingestion of xylitol and glucose solutions, respectively. Glucose suppressed motilin and stimulated GIP secretion; xylitol stimulated motilin secretion but had no effect on GIP, which is currently the main candidate for the role of enterogastrone. The accelerated intestinal transit and increase in plasma motilin observed after xylitol ingestion were thought to be causally related to the diarrhea and gastrointestinal discomfort produced by it.

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Fourteen of 16 patients with Cushing's syndrome due to adrenal adenoma who had undergone adrenal surgery in the period 1967-1981 participated in a follow-up study 1 to 15 (mean 4.5) years after the operation. There were 14 unilateral and two bilateral adenomas. Two patients have died: one from postoperative complications, the other by suicide 10 years after surgery. None of the patients relapsed and none showed clinical features of Cushing's syndrome. However, five patients remained obese and four hypertensive. Furthermore, in the female patients the bone mineral density was lower than in age-matched controls. The function of the pituitary-adrenal axis recovered slowly. Postoperative replacement therapy was withdrawn 3 to 28 (mean 11.8) months after surgery in all but one patient. The function of the remaining adrenal gland was completely normal in 10 patients. In two patients the plasma cortisol response to ACTH-stimulation was still blunted and associated with elevated plasma ACTH-levels. The plasma ACTH-level was low in the only patient having persistent hypocortisolism. In conclusion, the results show that most patients with Cushing's syndrome due to adrenal adenoma recover fully after surgery. In some patients, however, the suppressed pituitary and/or adrenal fail to resume normal function.

Clodronate, an inhibitor of osteoclast function, reduces bone resorption in osteolytic metastases and in multiple myeloma. We have evaluated its ability to decrease bone destruction in patients with multifocal eosinophilic granuloma of the skeleton. Two patients, whose multifocal bone granulomas appeared with a frequency of about 6 months, received 1.6 g day-1 oral clodronate for 6 months. Both patients had a reduction in serum calcium level which was accompanied by a decline in the fasting urinary hydroxyproline/creatinine and calcium/creatinine ratios and a slight increase in parathyroid hormone (PTH) level. Pain relief was observed in both patients. No new bone lesions were seen during the treatment and the old lesions healed. After discontinuing the therapy, however, new painful lesions appeared after 5 years in patient 1 and after 3, 4 and 5 years in patient 2. We suppose that clodronate delayed the appearance of new granulomas.