A B S T R A C T The hypothesis that clinical and biochemical essential fatty acid deficiency (EFA) might occur from the feeding of eucaloric, fat-free diets was tested in two experiments in healthy men. In Study I, eight men were given fat-free, eucaloric diets containing 80% of calories as glucose and 20% as amino acid hydrolysates by a constant drip over a 24-h period. The diets were fed in succession for periods of 2 wk each, either through a superior vena cava catheter or via a nasogastric tube. EFA deficiency was detected by decreases in linoleic acid and by the appearance of 5, 8.11-eicosatrienoic acid in lipid fractions of plasma. Linoleic acid decreased significantly during 2 wk of the fat-free diet given intravenously from 48.8 to 9.8% (percent of total fatty acids) in cholesterol esters, from 21.2 to 3.2% in phospholipids, from 9.6 to 2.0% in free fatty acids, and from 14.1 to 2.6% in triglycerides. Eicosatrienoic acid, normally undetectable, appeared 0.6% in cholesterol esters, 2.5% in phospholipids, 0.2% in free fatty acids, and 2.3% in triglycerides. EFA deficiency occurred similarly during the nasogastric feeding.In Study II a subject received the same diet continuously by the nasogastric route for 10 days followed by a 24-h fast. He was then given the fat-free diet intermittently in three meals per day for 3 days. Finally. he was repleted with a diet containing 2.6% linoleic acid. By the 3rd day of the continuous nasogastric feeding, linoleic acid had fallen significantly and eicosatrienoic acid had appeared in plasma lipid fractions as in Study I. These findings were accentuated by day 10. Adipose tissue fatty acid composition did not change. Free fatty
Recent studies indicate that long-term total parenteral nutrition (TPN) induces gallstone formation and acalculous cholecystitis in humans. Cholecystectomy is hazardous for these patients because they frequently have multiple medical problems and have undergone numerous abdominal operations. The present study was designed to develop a method to prevent TPN-induced gallbladder disease. The authors tested the hypothesis that a single daily intravenous infusion of cholecystokinin-octapeptide (CCK-OP) will prevent TPN-induced gallbladder stasis. Eleven prairie dogs received TPN for 10 days. Six of these animals were given a daily infusion of CCK-OP. Control animals were fed ad lib. Each animal's bile salt pool was labeled with intravenous 3H-cholic acid 16 hours prior to acute terminal experiments. The ratio ofgallbladder to hepatic bile 3H-cholic acid specific activity (Rsa) provides an index of gallbladder stasis. A Rsa of less than 1.0 indicates gallbladder stasis. TPN animals had a Rsa of 0.54 ± 0.13 (p < 0.01 vs. controls), indicating stasis of bile in the gallbladder. Daily CCK-OP infusions resulted in a Rsa of 0.92 ± 0.10 (p < 0.05 vs. TPN without CCK-OP), indicating that TPN-induced gallbladder stasis is prevented by daily CCK-OP. Control animals had a Rsa of 1.03 ± 0.06. The c4plesterol saturation indices of gallbladder and hepatic bile were not increased by TPN or CCK-OP. These data indicate that 1) TPN induces gallbladder stasis but does not increase bile lithogenic index; and 2) daily injections of CCK-OP prevent TPN-induced gallbladder stasis. SEVERAL RECENT REPORTS1-4 have documented an increased incidence of gallbladder disease in patients receiving long-term total parenteral nutrition (TPN). Although the pathogenesis ofthis phenomenon is not entirely clear, both human4'5 and animal studies6'7 suggest that the majority of gallstones that form during parenteral nutrition are pigment stones. In previous studies6'7 in the prairie dog, we have shown that TPN produces gallbladder stasis but does not alter either cholesterol saturation index or bile salt pool size. The observations of gallbladder distention8 and false-positive PI
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