Effects of xylitol on gastric emptying and food intake.

We studied the effects of xylitol, the pentose-sugar alcohol, on gastric emptying of the solid-food component of a complex meal. Gastric emptying was measured in human volunteers by utilizing a standardized radiolabeled scrambled-egg meal. After ingestion of 25 g xylitol, gastric emptying was markedly prolonged (T-1/2 58 +/- 5 min control vs 91 +/- 7 min after xylitol [p less than 0.01]). Since delayed gastric emptying may affect food intake, we evaluated the effects of xylitol on calorie intake. Food intake after oral preloading with water resulted in intake of 920 +/- 60 kcal vs 690 +/- 45 kcal after 25 g of xylitol. In contrast, a preload of glucose, fructose, or sucrose failed to suppress food intake. Although xylitol decreased food intake and also delayed gastric emptying, these effects may be unrelated. Our data suggest a role for xylitol as a potentially important agent in dietary control.

Do calories, osmolality, or calcium determine gastric emptying?

To determine whether calories, osmolality, or calcium mediate gastric emptying we employed a standardized radioactive meal in 10 normal human volunteers. A variety of simple and complex sugars, medium-chain fatty acid (MCFA), pectin, and gluten were dissolved in water and ingested with the test meal. The studies were also performed with calcium chloride, EDTA, and an equimolar combination of these chemicals. Results of gastric emptying showed that incremental glucose produced an increase in emptying time with a tendency for emptying time to show a proportionally greater delay with increasing glucose concentrations. Fructose and polyhexose had similar effects to glucose. Pentoses (xylose and arabanose) markedly prolonged gastric emptying when compared with the same amount of glucose. The effect of sucrose and gluten on gastric emptying did not significantly differ from controls. Twenty-five grams MCFA had an effect similar to 50 g glucose. Pectin, a complex carbohydrate, produced a varied effect in different individuals. There was no obvious relationship between osmolality and gastric emptying. Calcium chloride and EDTA prolonged gastric emptying, but the equimolar combination gave values similar to controls. Our findings suggest 1) calories nor osmolality alone determine gastric emptying, 2) both calcium and calcium chelation with EDTA prolong gastric emptying, and 3) a specific food does not necessarily produce the same effect on gastric emptying in different individuals.

The effects of Lipomul, CCK, and TRH on gallbladder emptying.

Tc-99m IDA compounds have been used in the quantitative analysis of motor function of the gallbladder. However, stimuli to provoke emptying have been variable and frequently nonphysiologic. To determine the utility and dependability of provocative agents for gallbladder emptying, we studied the effects of Lipomul, CCK, and TRH after the intravenous administration of Tc-99m disofenin. Computer processing of region-of-interest over the gallbladder permitted time/activity analysis of each study and computation of the ejection fraction (EF). Results showed that Lipomul consistently produced an effect on gallbladder emptying (EF 16-42%). CCK, while more dramatic in response, was less predictable (EF 8-100%). TRH favored accumulation of activity and did not cause gallbladder emptying. The combination of CCK and TRH decreased the rate of gallbladder emptying produced by CCK alone. We conclude that the availability, low cost, and dependable effect on gallbladder emptying make Lipomul the gallbladder stimulant of choice for clinical use.

The role of Tc-99m phosphate complexes and gallium-67 in the diagnosis and management of maxillofacial disease: concise communication.

Osteomyelitis of maxillofacial bones is difficult to differentiate from the results of trauma or malignancy, yet successful management is dependent upon early diagnosis and appropriate therapy. To determined if gallium-67 could differentiate infection from trauma or malignancy, 61 Tc-99m phosphate scans and 52 gallium-67 scans were made in 42 patients with maxillofacial disease. In all patients, definitive diagnosis was determined by surgery and/or clinical followup. Bone scans were positive in 37 patients. Gallium-67 scans were positive in 16 patients. Subsequent surgery and/or clinical followup demonstrated active osteomyelitis in 15 patients. From the data we conclude that: (a) the addition of Ga-67 scanning to the bone scans in evaluation of maxillofacial disease contributes significantly to differentiating trauma from osteomyelitis; (b) radiographic changes do not accurately reflect bone activity or differentiate osteomyelitis from trauma or malignancy; and (c) reduction in accumulation of gallium-67 in followup scans is a useful indicator for the termination of therapy in osteomyelitis.

Effect of hemodialysis on gallium-67-citrate scanning.

Gallium-67-citrate scanning is often used in the diagnosis of inflammatory processes in hemodialysis patients. The question arises whether the dialysis process will adversely affect the quality of the gallium scan. To answer this question, nine dialysis patients were studied, eight on hollow-fiber dialysis units and one on ultrafiltration, in an attempt to quantitate the loss of gallium through dialysis. Blood sampling during dialysis failed to demonstrate changes in gallium concentration attributable to removal by dialysis. Sampling of dialysate demonstrated levels of activity significantly greater than background; however, quantitation was not reliable. Ultrafiltration with total collection of extracted fluids yielded 0.5% of injected dose removed from the blood. Whole-body scans at 24 hours postinjection showed good quality and total counts unaltered by dialysis. The time of injection prior to dialysis also showed no effect on the quality of the final image.