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Biomedical subjects

V K Babayan

Publications and source records attributed to V K Babayan.

At least 37 records · Page 2Linked to original sources

Medium chain triglycerides and structured lipids as unique nonglucose energy sources in hyperalimentation.

This brief review will discuss recent work concerning new intravenous lipid emulsions for future use in clinical patients. Intravenous lipid emulsions currently available in the United States are derived from soybean or safflower oils and serve as sources of nonglucose, nitrogen-sparing calories and the essential fatty acid linoleic acid. Because of concerns that much of the infused long chain triglyceride is not oxidized readily and that there may be some immune system impairment, newer emulsions utilizing medium chain triglycerides have been developed.

Animals↗

Short-term administration of parenteral glucose-lipid mixtures improves protein kinetics in portacaval shunted rats.

The efficacy of various total parenteral nutrition regimens administered for 72 h in supporting the rat after portacaval anastomosis was evaluated. All animals that received amino acid-containing formulas had significantly improved nitrogen balance (p less than 0.05), albumin synthetic rates (p less than 0.05), and serum albumin concentration (p less than 0.05) compared with animals receiving dextrose only. Rats that received the mixed-fuel system containing amino acids, dextrose, and lipid had significantly improved leucine flux and whole body protein synthesis (p less than 0.05) compared with animals that received dextrose only, or amino acids and dextrose. Diets composed of dextrose only, amino acids and dextrose, or amino acids and dextrose with the addition of currently available long-chain triglyceride lipid emulsion induced abnormal morphologic changes in the liver. No hepatic morphologic changes were evident in rats that received an isocaloric mixed-fuel regimen containing medium- and long-chain triglycerides. The results suggest that mixed-fuel systems containing amino acids and dextrose with lipids are superior to formulas containing dextrose only, or dextrose with amino acids. The improved liver morphology observed in animals given the lipid emulsion system containing medium- and long-chain triglycerides suggests that medium-chain triglycerides may provide an additional benefit in supporting the patient with liver dysfunction.

Amino Acids↗

Lipid emulsions and reticuloendothelial system function in healthy and burned guinea pigs.

The effect of total parenteral nutrition (TPN) regimens containing various quantities of long-chain triglyceride (LCT) and medium-chain triglyceride (MCT) emulsions on bacterial clearance and organ sequestration was evaluated in healthy and burned guinea pigs. In healthy guinea pigs, increasing the LCT component of TPN to 75% or greater of the nonprotein calories resulted in hepatomegaly, splenomegaly, a significant reduction in the sequestration of intravenously administered Pseudomonas aeruginosa by the liver and spleen, and a markedly increased clearance of bacteria into the lung. In burned guinea pigs, replacement of LCT with MCT emulsions at 75% of the nonprotein caloric intake reduced the sequestration of bacteria in the lung and restored to normal hepatic and splenic uptake. These results suggest that LCT emulsions at 75% of nonprotein calories result in reticuloendothelial system overload and increased bacterial sequestration in the lungs in normal and burned animals. In contrast, administration of MCT emulsions to the burned animal is less likely to result in increased pulmonary sequestration and decreased hepatic or splenic reticuloendothelial system function.

Animals↗

Protein metabolism during total parenteral nutrition (TPN) in injured rats using medium-chain triglycerides.

There are metabolic limitations to the infusion of large quantities of dextrose in critically ill patients receiving total parenteral nutrition. Of the alternative, nonprotein lipid sources, medium chain triglycerides (carbon chain length 8 and 10) are more rapidly oxidized and are deposited in the adipose tissue at rates much less than long chain triglycerides. In rats with burn injury receiving hypocaloric (dextrose and amino acids) parenteral feeding, we studied the changes in protein metabolism as a result of increasing the caloric intake by 33% by the addition of either dextrose, a soybean oil emulsion, a medium chain triglyceride emulsion, or a structured lipid emulsion of triglycerides synthesized from safflower oil (40%) and medium chain triglycerides (60%). Changes in body weight, blood glucose concentration, beta-hydroxybutyrate, lactate, amino acids, insulin, albumin, liver protein content, and nitrogen balance were measured during three days of feeding. Whole body leucine kinetics and muscle protein fractional synthetic rate were evaluated using a constant intravenous infusion of L-[1-14C]leucine. The addition of dextrose or soybean oil emulsion produced a significant increase in body weight and liver nitrogen but did not change albumin concentrations or leucine kinetics compared to those of the hypocaloric feeding group. Rats receiving medium chain triglycerides and structured lipid emulsions showed a reduction in branched chain amino acid concentrations and an improvement in serum albumin levels. However, the rats receiving the structured lipid emulsion also showed increased body weight, had a significant decrease in leucine oxidation, and showed a three day cumulative nitrogen balance significantly greater than zero.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Structured medium-chain and long-chain triglyceride emulsions are superior to physical mixtures in sparing body protein in the burned rat.

The present study was undertaken to compare the effectiveness of a physical mixture of long-chain and medium-chain triglycerides with an emulsion consisting of chemically synthesized triglycerides composed of medium-chain and long-chain fatty acids in similar proportions. Sprague-Dawley rats received a 25% body surface area full-thickness scald burn on the dorsum. For the next three days, all rats received 300 kcal/kg/day as 160 kcal/kg/day glucose, 50 kcal/kg/day amino acid, and an additional 90 kcal/kg/day lipid emulsion as either long-chain triglyceride, medium-chain triglyceride, a 1:1 physical mix of medium-chain and long-chain triglycerides or a chemically structured triglyceride made up of 60% medium-chain fatty acid and a 40% safflower oil. Rats receiving the chemically structured lipid emulsion showed the greatest gain in body weight, the greatest positive nitrogen balance, and the highest serum albumin concentration, outstripping rats receiving the long-chain triglyceride, medium-chain triglyceride, and even the physical mixture long-chain and medium-chain triglycerides (P less than 0.01). A 30% increase in oxygen consumption and 35% increase in energy expenditure in rats given the medium-chain triglyceride emulsion alone (P less than 0.01) was observed. This study confirms that the metabolism of chemically structured triglycerides composed of medium-chain and long-chain fatty acids markedly differs from similar physical mixtures. For these reasons, the new structured lipid emulsions may prove advantageous in feeding the severely injured patient.

Amino Acids↗

Can protein-fortified pasta serve as a meat substitute?

A seventeen-day metabolic balance study was conducted with 13 healthy adult subjects to test the protein utilization of a meat-based diet and a protein-fortified pasta diet in an isonitrogenous, isocaloric inpatient study (averaging 112 gm of protein, and 2,500 cal). Intakes of calories, protein, fat, and carbohydrates, as well as ratios of meat protein or protein-fortified pasta protein (PEP), were controlled throughout the diets. The study was comprised of three experimental periods: a seven-day meat-protein control period, representing the typical american diet (TAD), averaging 18% protein, 40% fat, and 42% carbohydrate, a seven-day protein-enriched pasta control period (PEP), averaging 18% protein, 29% fat, and 53% carbohydrates, and a three-day PEP period composed of varied recipes, averaging 18% protein, 29% fat, and 53% carbohydrates. The subjects who consumed both the TAD and PEP diets achieved nitrogen balance (2.5 gN +/- 0.7 on the TAD, 2 gN +/- 0 on PEP with the PEP diet resulting in a decrease in plasma cholesterol (32 mg/dl, P less than .005), and a decrease in systolic (5.25 mm/Hg P less than .025) and diastolic blood pressure (5 mm/Hg, P less than .05), which was associated with an increase in urinary sodium excretion (19 +/- 17 mEq/day, P less than .025). In this study, it was determined that protein-fortified pasta may serve as a meat alternative. The PEP diet, which includes a beneficial change in fat/carbohydrate ratio, can alter lipid profiles, blood pressure, and sodium excretion, thus leading to improved health status and a decrease in cardiac risk factors.

Adult↗

Medium-chain triglycerides: an update.

A review of the literature on the medical and nutritional use of medium-chain triglycerides (MCTs) since 1970 is presented with additional discussions on the various modifications and applications of the MCTs in the synthesis of certain structured lipids. The metabolism of MCTs in the liver and extrahepatic tissues is discussed along with further documentation of the use of MCTs in malabsorption and hyperlipidemia cases. Recent applications of MCTs and modified MCTs in hyperalimentation, deficiency in the carnitine system, epilepsy, obesity, and other special areas of application are cited. The use of medium-chain monodiglycerides for dissolving cholesterol gallstones is presented. The contraindications for the use of MCTs in ketosis, acidosis, and cirrhosis are also discussed. Suggestions for use of MCTs in a variety of medical and nutritional applications are presented.

Animals↗

In vitro dissolution of gallstones: comparison of monooctanoin, sodium dehydrocholate, heparin, and saline.

A new gallstone solvent, monooctanoin, was tested in vitro on gallstones from 43 patients and compared with heparin, sodium dehydrocholate, and saline. Monooctanoin proved to be an excellent solvent, far superior to the other agents. It can completely dissolve or substantially reduce the size of most gallstones (except those composed of bilirubinate) in a relatively short time. Monooctanoin has been used on the bile duct stones in humans with favorable results. It can often eliminate the need for basket extraction of retained bile duct calculi. Potentially, it may be used to dissolve bile duct or gallbladder calculi in patients who are poor surgical risks.

Caprylates↗

Retained biliary tract stones. Nonsurgical treatment with capmul 8210, a new cholesterol gallstone dissolution agent.

The ability of Capmul 8210, a commercial solvent that predominantly consists of glyceryl 1-mono-octanoate, to dissolve retained common duct stones by direct infusion into the T-tube was tested in 20 patients with a total of 43 stones. Of 19 patients who completed their infusion, stone disappearance was observed in 15, giving a success rate of 79%. The dissolution time for a single stone averaged four days. A slight rise in serum alkaline phosphatase and amylase levels occurred in some patients, and rapidly returned to normal when treatment was concluded. Other side effects, such as nausea and vomiting epigastric discomfort, or diarrhea, occurred occasionally but were easily controlled medically. We believe that this agent is a useful adjunct in the management of postoperative choledocholithiasis in the patient with an indwelling T-tube.

Alkaline Phosphatase↗

Monooctanoin, a dissolution agent for retained cholesterol bile duct stones: physical properties and clinical application.

A commercial emulsifying agent consisting largely of glyceryl-l-monooctanoate (monooctanoin) was found to be an excellent cholesterol solvent. In vitro, the agent dissolved mixed cholesterol gallstones more than twice as fast as sodium cholate solutions, which have been previously used for dissolution of retained cholesterol bile duct stones by T-tube infusion. To test clinical efficacy, the solvent was infused, via T-tube, into 12 patients with retained bile duct stones. Some or all of the stones disappeared in 10 patients during biliary tract infusion of monooctanoin for 4--21 days. Stones from the 2 patients whose stones did not disappear were removed surgically and in vitro were found to be insoluble in monooctanoin. Monooctanoin infusions were well tolerated. This digestible solvent appears to be a useful substance for direct physical dissolution of retained bile duct stones by T-tube infusion.

Adult↗

Studies in man of partially absorbed dietary fats.

A saturated long-chain triglyceride (SLCT) has been prepared by esterification with glycerol of the saturated long-chain fatty acid fraction of coconut oil, isolated by molecular distillation of the hydrolyzed oil. The resultant SLCT is comprised principally of stearate (89%) and palmitate (11%). The intestinal absorption of SLCT in man was compared with that of corn oil or a 1:1 mixture of SLCT and corn oil. Each fat or the mixture was incorporated in isocaloric amounts into a complete formula diet deriving 30% of its caloric content from fat, 55% from carbohydrate (dextrose), and 15% from protein (casein). The formula diets were administered in sequential feeding periods as the sole source of food. The results indicate that SLCT was poorly absorbed (31 to 39%) compared with virtually complete absorption of corn oil (98%). Fat absorption was improved when the dietary fat was an equal mixture of SLCT and corn oil. The poor absorption of SLCT was ascribed to its high melting point and related to impaired emulsification and micellar solubilization in the small intestine.

Dietary Fats↗