bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of L‐Glutamine on Hepatic Lipids at Different Energy Levels in Rats Receiving Total Parenteral Nutrition
Authors: Yeh Sung Ling , Chen Wei Jao , Huang Po Chao
Published: May 2008

The effect of glutamine on hepatic steatosis and serum amino acid pattern was studied in rats receiving total parenteral nutrition (TPN) with different levels of caloric intake. Rats were divided into four groups; a control group (n = 10) was fed a chow diet and infused with saline only. Three experimental groups (n = 8 to 10) received TPN solutions at energy levels of 25 kcal, 30 kcal, and 35 kcal/100 g body weight, respectively. The experimental groups were maintained with TPN for a period of 6 days. Each experimental group was divided into two subgroups, one of which was supplemented with glutamine, replacing 40% of the total amino acid nitrogen. All of the basal TPN solutions were isonitrogenous and identical in nutrient composition, except for the difference in energy level, which was adjusted with glucose. The results demonstrated that liver fat increased in accordance with the increase of glucose supply, and this increase was mainly due to triglyceride accumulation. Very‐low‐density lipoprotein‐triglyceride and serum free fatty acid were significantly higher in the 30‐kcal groups. There were no differences in hepatic lipid content, very‐low‐density lipoprotein‐triglyceride secretion, or hepatic uptake of fatty acids between subgroups with and without glutamine supplementation. It was concluded that glutamine enrichment of a TPN solution did not have any effect on hepatic steatosis in normal rats. (Journal of Parenteral and Enteral Nutrition 18:40–44, 1994)
Soy Fiber Delays Disease Onset and Prolongs Survival in Experimental Clostridium difficile Ileocecitis
Authors: Frankel Wendy L. , Choi David M. , Zhang Wei , Roth Jonathan A. , Don Sidney H. , Afonso Juan J. , Lee Fang‐Hua , Klurfeld Dave M. , Rombeau John L.
Published: May 2008

Clostridium difficile colitis is a disabling complication in critically ill patients who commonly receive broad‐spectrum antibiotics and liquid diets. To date, there is no experimental model specifically designed to investigate the effects of liquid diets on this type of colitis. The addition of fiber to liquid diets normalizes gut structure and improves absorptive function in selected conditions of intestinal dysfunction. The purposes of this study were the following: (1) to develop a reproducible model to examine the interaction of acute C difficile‐induced colitis and liquid diets, (2) to determine whether the addition of soy fiber to a liquid diet improves disease, and (3) to investigate possible mechanisms of fiber‐mediated disease improvement. Syrian hamsters were pair‐fed with either a polymeric liquid diet or the same diet with 1.4% soy fiber for 10 days. Animals were given either clindamycin and C difficile (to produce ileocecitis), or equivalent volumes of saline. Mean survival time and systematic stool examinations for C difficile toxin positivity, liquidity, and percent water were performed to determine the effect of soy fiber on disease. Survival time was prolonged by 34% (p <.05), and C difficile toxin positivity and stool liquidity were significantly reduced (p <.05) with fiber. Additional animals were studied to determine possible mechanisms for improved survival in fiber‐supplemented animals. Cecal histology, colonic water absorption, cecal microflora, and gastric to anus transit time were measured in these animals. Colonic water absorption and gastric to anus transit time were significantly increased (p <.05) and decreased (p <.05) with fiber, respectively. A hamster model of C difficile ileocecitis has been designed to investigate the effects of liquid diets. Fiber supplementation prolongs survival in this model due in part to a delay in onset of C difficile infection and improved colonic water absorption. (Journal of Parenteral and Enteral Nutrition 18:55–61, 1994)
The Effect of Catheter Type and Site on Infection Rates in Total Parenteral Nutrition Patients
Authors: Kemp Lisa , Burge Jean , Choban Patricia , Harden Jaculin , Mirtallo Jay , Flancbaum Louis
Published: May 2008

Infections pose a major problem in patients receiving total parenteral nutrition. Controversy continues concerning the effect of catheter type (triple‐, double‐, single‐lumen, or pulmonary artery), insertion site (subclavian, internal jugular, or femoral vein), and the incidence of catheter‐related infections. We retrospectively studied multi‐lumen catheter use for total parenteral nutrition over a 6‐month period in 192 patients, a total of 3334 catheter days. Nonintensive care unit catheters were inserted by the Nutrition Support Service, and intensive care unit catheters were inserted by the intensive care unit staff. All catheters were cared for using Nutrition Support Service protocols, with multi‐lumen catheters changed every 7 to 10 days and pulmonary artery catheters changed every 4 days. Infections were determined by semiquantitative cultures (>15 colonies/plate). The incidence of infections for triple‐lumen catheters was 5 (subclavian), 17 (internal jugular), and 36% (femoral) respectively; total infection rate for triple‐lumen catheters was 10%. Infection rates for pulmonary artery catheters were 4 (subclavian), and 6% internal (jugular site), respectively, the overall infection rate was 5%. There were no differences in infection rates at any site based on catheter type; however, when triple‐lumen catheter sites were compared, the differences were significant (p <.001 vs subclavian, χ2). Catheter duration was 7.8 days (subclavian), 7.3 days (internal jugular), and 4.6 (femoral) days. These data suggest that the use of multi‐lumen catheters for total parenteral nutrition is safe, that there is a benefit associated with the subclavian route, and that the femoral site should be avoided. (Journal of Parenteral and Enteral Nutrition 18:71–74, 1994)
Elemental Diets May Accelerate Recovery from Total Parenteral Nutrition‐Induced Gut Atrophy
Authors: Mukau Lesue , Talamini Mark A. , Sitzmann James V.
Published: May 2008

Prolonged bowel rest and total parenteral nutrition lead to gastrointestinal mucosal atrophy. The possibility that enteral diets of varying composition could have a beneficial effect in reversing total parenteral nutrition‐associated gut atrophy was investigated. A group of male Sprague‐Dawley rats were randomized to receive TPN for 10 days, followed by 10 days of elemental or regular food. The effects of these diets on body mass, gastro‐intestinal index (intestinal weight divided by body weight), mucosal incorporation of titrated thymidine, and intestinal villi length were compared. Significant gut villi atrophy and use of gut weight occurred in rats receiving TPN and bowel rest compared with the fed control group. These changes were significantly reversed by elemental diets, but not by rat food diets. We conclude that elemental diets may enhance gut recovery after prolonged TPN and bowel rest in a rat model. (Journal of Parenteral and Enteral Nutrition 18:75–78, 1994)
The Uterine Sound as a Convenient, Cost‐Effective Method for Creating the Subcutaneous Tunnel for Long‐Term Venous Catheters
Authors: Waddell Brad E. , Martindale Robert G.
Published: May 2008

Long‐term central venous access catheters generally require creating a subcutaneous tunnel to minimize infectious complications and secure the catheter to the chest wall. Many techniques for this procedure have been reported. We describe the use of a uterine sound to create the subcutaneous tunnel. (Journal of Parenteral and Enteral Nutrition 18:81–82, 1994)
A Randomized Study of a pH Sensor Feeding Tube vs a Standard Feeding Tube in Patients Requiring Enteral Nutrition
Authors: Alin Botoman V. , Kirtland Steven H. , Moss R. Lawrence
Published: May 2008

Postpyloric feedings are a widely practiced form of enteral nutrition. We prospectively randomized two groups of hospital patients to receive a standard feeding tube or a feeding tube that uses a pH sensor to facilitate postpyloric placement and compared placement speed and accuracy, displacement detection, and costs for the two groups. Thirty‐nine patients were randomized, with 20 receiving a pH sensor feeding tube and 19 an identical non‐pH sensor feeding tube. An x‐ray of the kidneys, ureter, and bladder was taken at 1, 6, and 48 hours after placement in both groups. Separate cost‐benefit analyses were done by using retrospective chart review of costs for a separate 20‐patient standard feeding tube group and calculated costs for a 20‐patient hypothetical pH sensor group. At 1 hour, the duodenum was reached in 53% of the pH sensor feeding tube patients and 45% of the standard feeding tube patients (the difference was not significant). At 48 hours, 93% of the pH sensor feeding tubes reached the duodenum vs 67% of the standard feeding tubes (p <.08). Thirty percent of the pH sensor patients had an initial gastric pH ≥4, negating pH sensor benefit in tube placement. In the remaining 70% of the patients, placement with the pH sensor had a 100% specificity compared with the x‐ray of the kidneys, ureter, and bladder. Displacement was easily detected with routine pH monitoring in three of the pH sensor feeding tube patients and corrected. It was detected in two standard feeding tube patients, one of whom aspirated. Cost‐benefit analysis incorporating the above findings showed a cost savings of $81.00 per patient for the pH sensor feeding tube, more than the cost of the tube. Thus, pH sensor feeding tubes may obviate the need for confirmatory x‐rays in patients without hypochlorhydria, resulting in potential significant savings. (Journal of Parenteral and Enteral Nutrition 18:154–158, 1994)
The Modulatory Role of Gut Hormones in Elemental Diet and Intravenous Total Parenteral Nutrition‐Induced Bacterial Translocation in Rats
Authors: Haskel Yuval , Xu Dazhong , Lu Qi , Deitch Edwin A.
Published: May 2008

We have previously shown that parenteral and certain elemental diets promote bacterial translocation and that this diet‐induced bacterial translocation can be prevented by the provision of bulk‐forming dietary fiber. The goal of the current study was to test the hypothesis that fiber's protective effect on diet‐induced bacterial translocation was mediated by trophic gut hormones. This hypothesis was tested by using bombesin (which stimulates gut hormone release) or the somatostatin analog Sandostatin (which inhibits gut hormone release) to modulate gut hormone release in rats receiving rat food, intravenous total parenteral nutrition, or an elemental diet. Both bombesin and fiber were effective in preventing elemental diet‐induced bacterial translocation, whereas octreotide acetate abrogated the protective effect of fiber. Bombesin was also effective in limiting bacterial translocation in parenterally fed rats. Although both enteral (elemental diet) and parenteral diet‐induced bacterial translocation were associated with cecal bacterial overgrowth, loss of small‐bowel weight, and loss of mucosal protein content, none of these factors seemed to be primarily responsible for bacterial translocation. Because bombesin decreased the incidence of villous injury in the elemental diet‐fed rats and decreased the incidence of villous injury and prevented loss of intestinal barrier function to horseradish peroxidase in the parenterally fed rats, it is possible that bombesin exerted its protective effect by limiting mucosal injury and preserving barrier function. (Journal of Parenteral and Enteral Nutrition 18:159–166, 1994)
Enteral Supplementation of Phosphate Does Not Prevent Hypophosphatemia During Refeeding of Cachectic Patients
Authors: Maier‐Dobersberger Theresia , Lochs Herbert
Published: May 2008

Hypophosphatemia due to parenteral nutrition has been described frequently. It was attributed to the lack of phosphorus content in parenteral nutrition solutions. With modern parenteral nutrition regimens containing phosphorus, this problem has been virtually eliminated. Enteral nutrition solutions contain adequate phosphate for patients with normal phosphate stores. Hypophosphatemia has therefore rarely been reported in enteral nutrition. We describe two patients with protein‐energy malnutrition who developed severe hypophosphatemia during tube feeding with phosphorus‐containing formula diets. Chronic alcoholism and vitamin D deficiency due to malabsorption because of Crohn's disease were additional risk factors in these two patients. Patients with depleted phosphate stores and high metabolic demand have a higher daily requirement for phosphorus than is available in routine isotonic enteral formulas. This case report emphasizes the importance of monitoring serum phosphate concentration daily during the first week of refeeding. (Journal of Parenteral and Enteral Nutrition 18:182–184, 1994)
Copper Deficiency With Pancytopenia During Total Parenteral Nutrition
Authors: Wasa Masafumi , Satani Minoru , Tanano Hirofumi , Nezu Rchiro , Takagi Yoji , Okada Akira
Published: May 2008

Anemia and neutropenia are commonly observed hematologic changes in patients with copper (Cu) deficiency, but thrombocytopenia is rarely found. A‐69‐year‐old patient with postoperative small‐bowel obstruction underwent laparotomy three times. Because of persistent obstruction, nasoduodenal suction was continued and total parenteral nutrition was instituted. Fifteen months after the initiation of total parenteral nutrition, the patient gradually developed pancytopenia (red blood cell count 222 × 104/mm3, neutrophil count 1254/mm3, and platelet count 9.2 × 104/mm3). The serum Cu level was 10 μg/dL and the serum ceruloplasmin level was less than 5 mg/dL. After 2 weeks of Cu supplementation in a daily dose of 20 μmol, the serum Cu level increased to 81 μg/dL and the serum ceruloplasmin level to 20 mg/dL. Hematologic values showed a dramatic response: red blood cell count increased to 362 × 104/mm3, neutrophil count to 4819/mm3, and platelet count to 22.1 × 104/mm3. The improvement of pancytopenia could be attributed to Cu supplementation. This is the first case report of Cu deficiency with pancytopenia during total parenteral nutrition. (Journal of Parenteral and Enteral Nutrition 18:190–192, 1994)
Arginine Stimulates Wound Healing and Immune Function in Elderly Human Beings
Authors: Nussbaum Michael S.
Published: May 2008

This prospective randomized trial evaluated the effect of oral supplements of arginine aspartate on wound healing and immune responses in healthy elderly (over 65 years old) volunteers. This laboratory previously demonstrated that arginine supplementation enhances wound‐breaking strength, reparative collagen synthesis, and T‐cell‐mediated immune function in healthy animals and human beings,1,2 whereas immune suppression associated with trauma is abrogated.3 Thirty subjects received daily supplements of 30 g of arginine aspartate (17 g of free arginine) and 15 individuals received placebo syrup for a 14‐day course. Wound healing was evaluated by two methods: (1) fibroplasia was measured by using subcutaneously implanted polytetrafluoroethylene catheters for the determination of collagen deposition, total protein, and DNA content, and (2) rate of wound epithelialization was assessed by using a standard partial‐thickness wound. Lymphocyte blastogenesis was measured in a microculture system by using mitogenic stimulation with standard mitogens as well as alloantigens in a mixed lymphocyte response with stimulator cells collected from pooled healthy human donors. Serum insulin‐like growth factor‐1 (IGF‐1) was determined by radioimmunoassay.

Arginine supplementation enhanced wound fibroplasia as evidenced by an increase in the amount of collagen deposition and total protein content. However, DNA content and time to complete epithelialization were equivalent in both groups. The blastogenic response of peripheral blood lymphocytes to all mitogens and alloantigens was significantly enhanced in the arginine‐supplemented group. Serum IGF‐1 levels were also significantly elevated in the arginine group.
Body Composition: Research and Clinical Advances—1993 A.S.P.E.N. Research Workshop
Authors: Heymsfield Steven B. , Matmews Dwight
Published: May 2008

The 1993 ASPEN Research Workshop examined research and clinical advances in the study of human body composition. The workshop had two themes: (1) compartments of the body and their measurement, and (2) clinical applications of body composition measurements. There were 12 speakers of varied backgrounds who gave short lectures followed by panel discussions. Speakers explored the validity and potential uses of new body composition methodologies, including dual‐energy x‐ray absorptiometry, multiple frequency bioimpedance analysis, computerized axial tomography, magnetic resonance imaging, nuclear magnetic resonance spectroscopy, neutron inelastic scattering, and gamma‐ray resonance. The application of these methods to chronically and acutely ill hospitalized patients was described. The study of body composition is an emerging distinct research area within the broad study of human biology. This conference provided an overview of important new advances in the study of human body composition. (Journal of Parenteral and Enteral Nutrition 18:91–103, 1994)
Effects of the Short‐Chain Triglyceride Triacetin on Intestinal Mucosa and Metabolic Substrates in Rats
Authors: Lynch Jamie W. , Miles John M. , Bailey James W.
Published: May 2008

Diets containing either triacetin (the water‐soluble triglyceride of acetate) or long‐chain triglycerides (LCTs) were fed to rats to determine the effects on intestinal mucosa cells and plasma substrates. Male Sprague‐Dawley rats were fed one of three diets, a control diet containing 5% of energy as LCTs or one of two experimental diets that contained 30% of energy as lipid. The lipid component of the two experimental diets was either 100% LCTs or 95% triacetin/5% LCTs. Plasma lactate, glucose, and total ketone body concentrations were not significantly different among dietary treatment groups. Compared with animals fed LCTs and control diet, plasma pyruvate and free fatty acid concentrations were decreased in animals fed triacetin. In contrast, plasma triglyceride concentrations were elevated in animals fed triacetin compared with other groups. Intestinal biochemical measures included total DNA, RNA, protein, and the protein:DNA ratio. Histologic indices measured were villus height in the jejunum and crypt depth in the colon. No significant difference in mucosal protein concentration was observed in the jejunum and colon. Jejunal RNA was significantly decreased in animals fed triacetin compared with other diets. Triacetin feeding significantly increased the DNA content in the jejunum and colon (thereby lowering the protein:DNA ratio), indicating smaller, more numerous cells. Jejunal villus height and colonic crypt depth were not significantly different among dietary treatment groups. Provision of a balanced diet containing 28.5% of the total calories as triacetin had no adverse effects on metabolic substrates and resulted in smaller and more numerous mucosal cells in the jejunum and colon. These data indicate that the short‐chain triglyceride triacetin could aid in the maintenance of gut integrity and in the treatment of certain intestinal disorders. (Journal of Parenteral and Enteral Nutrition 18:208–213, 1994)
Anabolic Effects of Insulin and Amino Acids in Promoting Nitrogen Accretion in Postoperative Patients
Authors: Valarini R. , Sousa M.F. , Kalil R. , Abumrad N.N. , Riella M.C.
Published: May 2008

The present study evaluates the effect of insulin and amino acids on nitrogen balance in the immediate postoperative period in moderately stressed patients who have undergone major abdominal surgical operations. Patients were randomly assigned into two large groups (n = 16 each) and four subgroups (n = 8 each). Groups ICON and IINS received an infusion of total parenteral nutrition solution containing 0.25 g of nitrogen per kilogram per day with a calorie:nitrogen (C:N) ratio of 150:1. Groups IICON and IIINS received twice the load of nitrogen with a C:N ratio of 75:1. Groups IINS and IIINS received an additional continuous infusion of insulin at a rate of 1.0 mU/kg per minute for 7 days. During the total parenteral nutrition period, the patients were kept NPO, and 24‐hour urine output was collected for estimation of total nitrogen excretion and nitrogen balance. Net nitrogen excretion (grams per kilogram per day) averaged 0.143 ± 0.06 in IINS and 0.23 ± 0.08 in ICON (p <.05) and 0.178 ± 0.6 in IIINS and 0.25 ± 0.10 in IICON (p <.05). Nitrogen balance (grams per day) was positive in the four groups: +0.65 ± 3.8 in IINS and + 6.74 ± 2.94 in ICON (p <.05), and +14.4 ± 2.61 in IIINS and + 11.63 ± 6.44 in IICON (p = not significant). The average nitrogen incorporation (percent per day) was: 41.3 ± 6.2 in IINS and 14.6 ± 20.1 in ICON (p <.05), and 58.3 ± 4.5 in IIINS and 38.7 ± 26.2 in IICON (p = not significant). The results indicate that nitrogen balance in modestly stressed subjects is achieved at nitrogen intakes of approximately 0.25 g/kg and a C:N ratio of 150:1. Doubling the nitrogen intake while decreasing the C:N ratio of 75:1 resulted in higher positive nitrogen balance. Insulin infusion, to achieve physiologic elevation in plasma insulin (55 to 70 μU/mL), resulted in further improvement in positive nitrogen balance in the group receiving lower nitrogen intake, suggesting that the effect of amino acids in improving nitrogen accretion is saturable. (Journal of Parenteral and Enteral Nutrition 18:214–218, 1994)
Selenium Renal Homeostasis Is Impaired in Patients Receiving Long‐term Total Parenteral Nutrition
Authors: Buchman Alan L. , Moukarzel Adib , Ament Marvin E.
Published: May 2008

Selenium deficiency has been reported previously in patients receiving long‐term total parenteral nutrition (TPN) without selenium supplementation in their solutions. The recommended dietary allowance for selenium is 0.87 μg/kg, of which 80% is absorbed. We studied 28 adult long‐term TPN patients aged 21 to 79 years (mean, 51.2 ± 3.0 years) who have received TPN for 8.3 ± 4.4 years. They receive 40 to 60 μg of selenium daily in their TPN solution. Twenty‐one (75%) of 28 patients had low serum selenium levels. Of the patients with low serum selenium levels, 15 (73%) had elevated urinary selenium losses. However, no significant correlation between serum or urine selenium levels and glomerular filtration rate (measured by indium‐111‐diethylenetriamine pentaacetic acid clearance) or renal tubular function was observed. We conclude that the previously described renal homeostatic mechanism for selenium conservation may be significantly impaired in patients receiving long‐term TPN. Such patients may require much larger doses of selenium than previously recommended. Therefore, patients receiving long‐term TPN should have their serum selenium level monitored even though they receive daily selenium supplementation. (Journal of Parenteral and Enteral Nutrition 18:231–233, 1994)
Stability of Vitamins in Soybean Oil Fat Emulsion Under Conditions Simulating Intravenous Feeding of Neonates and Children
Authors: Dahl G.B. , Svensson L. , Kinnander N.J.G. , Zander M. , Bergström U.K.
Published: May 2008

The stability of the fat‐soluble vitamins and thiamine, riboflavin, pyridoxine, ascorbate, and folic acid when administered as part of Intralipid 10% was evaluated. Intravenous pediatric vitamin formulations (Vitalipid N Infant and Soluvit Infant) containing the daily dose for term neonates were diluted with Intralipid to final volumes of 12.5 mL or 260 mL. The volumes were then delivered for 24 hours via dihexylethyl‐phtalate‐free in vitro infusion systems that simulated clinical conditions. The first vitamin‐Intralipid admixture (12.5‐mL volumes) was pumped (by syringe) during 24 hours through neonatal infusion sets placed in an incubator (37 ± 1°C, bilirubin light). Aliquots were collected at the beginning of the experiment and after 24 hours of infusion. The second admixture (260‐mL volumes) was pumped (by a peristaltic pump) through infusion sets during 24 hours and was exposed to periodic indirect sunlight and to continuous fluorescent light to simulate the feeding of a child. Aliquots were collected at 0, 8, and 24 hours during administration of the admixtures. The vitamin concentrations were measured by high‐performance liquid chromatography. The effect of the vitamins on the stability of the emulsion was also assessed by visual inspection, lipid globule size distribution, and pH change. Losses of vitamins vary from different experimental conditions and were for the fat‐soluble vitamins essentially nil, except for phylloquinone, which was 5% to 17% below the initial level. Thiamine, pyridoxine, and folic acid were stable. Losses of riboflavin and ascorbate amounted to 10% to 20% and 9% to 52%, respectively. These results demonstrate that the vitamin stability is good when vitamins are administered in a vitamin‐Intralipid admixture. The addition of vitamins to Intralipid did not alter the stability of the fat emulsion for up to 24 hours at room temperature. (Journal of Parenteral and Enteral Nutrition 18:234–239, 1994)
Enteral Glutamine Spares Endogenous Glutamine in Chronic Acidosis
Authors: Welbourne T.C. , Joshi S.
Published: May 2008

Metabolic acidosis associated with the catabolic state mobilizes muscle nitrogen and releases it into blood as glutamine (GLN) targeted for renal consumption and base generation. Because GLN removed by the kidneys during acidosis is a major drain on the GLN available to other sites, subsequent deprivation may lead to impaired organ function. Conversely, GLN supplementation may spare endogenous supplies and restore organ function. To test this, Sprague‐Dawley rats weighing between 250 and 350 g were pair‐fed elemental diets supplemented with GLN 4.9 g/L (GLN‐ED) or an equivalent mixture of neutral amino acids substituted for GLN (ED). Acid loading was effected by adding hydrochloric acid to the liquid diet (110 mmol/L). Animals were studied in metabolic cages for five consecutive 24‐hour urine collection periods and then anesthetized for short‐term studies of interorgan fluxes and tissue GLN content. Acidosis effected an increase in ammonium nitrogen excretion (fivefold) and a reciprocal decrease (24%) in urea nitrogen excretion. Enteral GLN had no effect on the acidosis‐effected ammonium (2170 ± 71 vs 2059 ± 361 μmol/100 g, ED vs GLN‐ED, respectively) or urea excretion (5522 ± 95 vs 5915 ± 984 μmol/100 g, ED vs GLN‐ED, respectively). Although arterial blood GLN was not increased in the GLN‐ED group (531 ± 58 vs 438 ± 51 nmol/mL, p =.10), both liver and muscle GLN were elevated (11,650 ± 1137 nmol/g vs 7063 ± 578 and 5503 ± 489 and 4742 ± 333 nmol/g, respectively, each p <.05). GLN released by the hindquarter and liver and removed by the gut was monitored while the rats were under anesthesia by using simultaneously measured blood flow and arteriovenous blood concentration differences. Hindquarter GLN release decreased in the GLN‐ED group compared with the ED group (507 ± 104 vs 162 ± 148, p <.05). In contrast, gut GLN uptake was markedly increased in the GLN‐ED group (477 ± 153 to 931 ± 228 mmol/min per 100 g, p <.05), whereas hepatic release increased (134 ± 74 to 430 ± 132 nmol/min per 100 g, p <.05). Although splanchnic bed GLN balance registers net uptake, urea excretion was not enhanced with GLN‐ED; rather a large hepatic glutamate efflux appeared (343 ± 150 to 827 ± 240 mmol/min per 100 g, p <.05). Twenty‐four‐hour creatinine excretion increased with GLN‐ED, whereas 3‐methylhistidine excretion decreased (2.46 ± 018 vs 1.86 ± 0.10 μmol/100 g for GLN‐ED and ED, respectively, p <.05). These findings are consonant with enteral GLN supplementation effecting a reduced GLN flow from muscle and sparing proteolysis during chronic metabolic acidosis apparently dependent upon enhanced interorgan flux of the GLN precursor glutamate. (Journal of Parenteral and Enteral Nutrition 18:243–247, 1994)
Bioavailability of Magnesium Diglycinate vs Magnesium Oxide in Patients with Ileal Resection
Authors: Schuette Sally A. , Lashner Bret A. , Janghorbani Morteza
Published: May 2008

Background: Patients who have undergone ileal resection are at risk for developing magnesium depletion/deficiency because of poor absorption and decreased intake as well as increased endogenous losses. Magnesium repletion is difficult to accomplish because of the cathartic action of most oral magnesium supplements at therapeutic doses. The results of in vitro and in situ studies show that magnesium diglycinate (chelate) represents a highly available form of magnesium that is absorbed in part as an intact dipeptide in the proximal small intestine. Methods: We conducted a double‐blind, randomized crossover trial with 12 patients who had ileal resections in order to compare the bioavailability of a 100‐mg dose of 26Mg‐labeled chelate with MgO in this patient population. Results: For the patient group as a whole, 26Mg absorption was low but was not different for the two supplements (23.5% vs 22.8% for magnesium chelate and MgO, respectively). However, 26Mg absorption was substantially greater from the chelate (23.5% vs 11.8%; p <.05) in the four patients who showed the greatest impairment of magnesium absorption with MgO and was better tolerated by all patients. Peak isotope enrichment also occurred significantly earlier after 26Mg chelate than after 26MgO ingestion (mean difference 3.2 ± 1.3 hours; p <.05), and the area under the enrichment vs time curve was greater after chelate ingestion (p <.05). Conclusions: Data from this study support the suggestion that some portion of magnesium diglycinate is absorbed intact, probably via a dipeptide transport pathway. Magnesium diglycinate may be a good alternative to commonly used magnesium supplements in patients with intestinal resection. (Journal of Parenteral and Enteral Nutrition 18:430–435, 1994)
Infusion of Long‐Chain or Medium‐Chain Triglycerides Inhibits Peripheral Glucose Metabolism in Men
Authors: Stouthard Jacqueune M.L. , Endert Erik , Romijn Johannes A. , Sauerwein Hans P.
Published: May 2008

To investigate whether increased availability of lipids affects glucose metabolism in healthy postabsorptive men when lipid and glucose are infused in amounts used in parenteral nutrition, we infused glucose (4 mg/kg·min−1) for 6 hours and clamped plasma glucose at basal level during the first 3 hours. After 3 hours, either long‐chain triglycerides (LCTs) (0.07 g/kg·h−1) (n = 7) or a mixture of LCTs and medium‐chain triglycerides (MCTs) (MCTs/LCTs, 50/50%, 0.07 g/kg·h−1) (n = 7) was administered, and the infusion rates of glucose and insulin were unchanged compared with the first 3 hours. In a control study, glucose was infused for a period of 6 hours without the lipid infusion (n = 5). After 6 hours, the plasma glucose concentration and glucose tissue uptake were not affected by LCT or MCT/LCT infusion. Nonetheless, glucose oxidation decreased in the LCT group (from 6.42 ± 1.04 to 2.31 ± 0.85 μmol/kg·min−1, p <.001) and in the MCT/LCT group (from 7.62 ± 1.50 to 5.50 ± 0.76 μmol/kg·min−1, p <.01) but not in the control group. Concentrations of the glucoregulatory hormones were not different among the three groups. In conclusion, MCTs/LCTs administered concomitantly with glucose infusion, in amounts similar to those used in total parenteral nutrition, inhibit glucose oxidation without affecting glucose tissue uptake, just as LCTs do. (Journal of Parenteral and Enteral Nutrition 18:436–441, 1994)
Review: The Effect of Parenteral Nutrition on Hepatic Cytochrome P‐450
Authors: Earl‐Salotti Grace L. , Charland Scott L.
Published: May 2008

Background: Total parenteral nutrition (TPN) has been shown to affect liver function tests. Additional investigations in animals and humans have demonstrated that hepatic cytochrome P‐450 content and enzyme activity are also affected. Methods: To review the literature on the effect of TPN on hepatic cytochrome P‐450, an English‐language literature search was performed using MEDLINE (1966 through 1993). Results: Studies in laboratory rats show that administration of dextrose, with or without amino acids, decreases the cytochrome P‐450 content and the in vitro or in vivo microsomal oxidation rates of various drugs. The addition of lipid emulsions to TPN decreases oxidation rates for meperidine demethylase but does not affect ethoxyresorufin deethylase. Using immunoquantitation, it was shown that the components of TPN selectively affect specific hepatic P‐450 enzymes. In humans, dextrose decreases antipyrine clearance, whereas amino acids and possibly lipids increase antipyrine clearance. However, the effects of protein‐calorie malnutrition in these studies obscure the results. Conclusions: Possible mechanisms for the reduction of hepatic cytochrome P‐450 seen during TPN administration include altered gastrointestinal hormone response, mucosal barrier, and the effect of sepsis. Additional studies are needed to determine the actual mechanisms of hepatic cytochrome P‐450 reduction observed during TPN. (Journal of Parenteral and Enteral Nutrition 18:458–465, 1994)
Glutamine Enhances Immunoregulation of Tumor Growth
Authors: Fahr Michael J. , Kornbluth Jacki , Blossom Sarah , Schaeffer Robert , Kumberg V. Suzanne
Published: May 2008

Background: It is known that tumor progression is associated with a depletion in host glutamine (Gln) stores and a depression of natural killer (NK) cell activity. After demonstrating an in vitro dependence of NK cell activity on Gln and glutathione concentration, this study evaluated the effects of oral Gln on Gln and glutathione metabolism, NK cell activity, and tumor growth in the tumor‐bearing rat. Methods: Two days before tumor implantation, rats (n = 32) were randomized to receive Gln (1 g/kg/d) or an isonitrogenous amount of glycine by gavage and pair‐fed food. On day 21 after tumor implantation, rats were killed, and tumors were measured and processed for glutaminase activity, glutathione content, and tumor morphometrics. Splenic lymphocytes were assayed for NK cell activity via a chromium (51Cr) release assay using YAC (NK‐cell‐sensitive mouse tumor cell line) target cells. Blood Gln and glutathione were measured. A second set of rats (n = 16) were treated similarly except that ketamine was given twice weekly to suppress NK cell activity. Results: During the 3‐week study period, tumor growth was decreased by 40% in the Gln group. This decrease in growth was associated with a 30% increase in NK cell activity. Administration of ketamine to rats completely reversed the higher NK cell activity and decreased the tumor growth seen in the Gln‐treated group. Conclusions: These data indicate that oral Gln supplementation, through support of host Gln stores and glutathione production, may decrease tumor growth by enhancing NK cell activity. (Journal of Parenteral and Enteral Nutrition 18:471–476, 1994)
Effect of Dietary Restriction on the Response of α2‐Macroglobulin During an Acute Phase Response
Authors: Jennings Graham , Eua Marinos
Published: May 2008

The effects of aseptic abscesses induced by subcutaneous injections of turpentine (5 mL/kg body weight) on the acute‐phase protein response (α2‐macroglobulin, α2‐M) and on the circulating albumin and total protein concentrations were assessed in young rats that were made malnourished by restricting dietary intake to an extent that either impaired growth (60% of normal intake) or caused weight loss (0% to 45% of normal intake). The measurements were obtained daily during a period of 4 days in malnourished rats that had lost about 25% body weight but had maintained a stable weight thereafter, or in rats that had lost about 12% body weight and were continuing to lose weight at various rates at the time of the turpentine injection. In animals that were injected while they maintained a stable weight after losing about 25% body weight, the α2‐M response was attenuated fourfold to eightfold compared with control animals (the area under the 4‐day α2‐M curve in control rats was 23.3 ± 2.3 g/L/d). In the depleted animals that were injected while they were actively losing weight (∼12.5% weight loss), the attenuation of the α2‐M response was related to the rate of weight loss or to the extent of dietary restriction (area under the 4‐day α2‐M curve ranged from 5.7 ± 1.4 g/L/d in animals receiving 15% restricted diet to 15.6 ± 1.5 g/L/d in animals receiving the 45% restricted diet). The hypoalbuminemic response was similar in different groups, and the change in total protein concentration generally reflected the change in α2‐M response. The results suggest that dietary restriction can attenuate the acute‐phase protein response and that the magnitude of this attenuation depends not only on the extent of depletion but also on the rate with which the depletion is occurring. (Journal of Parenteral and Enteral Nutrition 18: 510–515, 1994)
The Effect of Glycosylated Albumin on Platelet Aggregation
Authors: Doweiko John P. , Bistrian Bruce R.
Published: May 2008

Background: Albumin has a role in the complicated process of platelet aggregation. Although it is known that quantitative changes in plasma albumin alter platelet aggregation, less is known about the interaction between qualitative changes in plasma albumin and platelets. One common qualitative change in plasma albumin is nonenzymatic glycosylation, which occurs during states of prolonged hyperglycemia. Methods: Albumin was selectively removed from normal plasma by means of an affinity column. Glycosylated albumin was added to this albumin‐poor plasma, and it was used to study platelet aggregation induced by low concentrations of arachidonic acid. Platelet aggregation was determined by light transmittance. Results: As the concentration of glucose in which albumin was incubated was increased, there was progressive augmentation of platelet aggregation. At a plasma glucose of 150 mg/dL, average light transmittance was 9.4%, and at 200 mg/dL, it was 24.6%. These values were significantly different at a p value <.01. At glucose levels of 300 mg/dL and 400 mg/dL, mean light transmittance was 40.6% and 74.4%, respectively, and these values were significantly different with p values of <.01. Conclusions: Platelet aggregation in response to a relatively low concentration of arachidonic acid is enhanced in the presence of albumin that has been incubated in a medium containing levels of glucose that are higher than would be seen in normal patients but are consistent with those seen in diabetics with less than optimal control. This augmentation of platelet aggregation is statistically significant. (Journal of Parenteral and Enteral Nutrition 18:516–520, 1994)
Pinch‐Off Syndrome: A Rare Etiology for Central Venous Catheter Occlusion
Authors: Andris Deborah A. , Krzywda Elizabeth A. , Scht‐Lte William , Ausman Robert , Quebbeman Edward J.
Published: May 2008

Background: Catheter pinch‐off syndrome is a rare and often misdiagnosed complication of tunneled Silastic central venous catheters. Pinch‐off syndrome occurs when the catheter is compressed between the first rib and the clavicle, causing an intermittent mechanical occlusion for both infusion and withdrawal. We report its incidence in a large series of catheter insertions and describe the clinical presentation, radiographic findings, and recommended treatment. Methods: A total of 1457 tunneled Silastic central venous catheters that were inserted using the percutaneous subclavian approach were prospectively studied. Indications for catheter placement included bone marrow transplant, continuous or intermittent chemotherapy, long‐term antibiotics, and parenteral nutrition. Catheters were evaluated for clinical presentation of an occlusion relieved by postural changes and radiographic findings of luminal narrowing. Results: Pinch‐off syndrome was identified in 16 (1.1%) catheters. Radiographic findings were present in all catheters; clinical findings were present in 15 catheters. Clinical symptoms presented within a median of 2 days after placement (range, 0 to 167 days). Partial or complete catheter transection, a serious sequela of catheter pinch‐off syndrome, occurred in 19% of the identified catheters. Conclusions: (1) Catheter pinch‐off syndrome presents clinically as a catheter occlusion related to postural changes; (2) clinical symptomatology should be confirmed radiographically; and (3) catheter removal with a more lateral replacement in the subclavian vein or in the internal jugular vein will avoid a recurrent complication. (Journal of Parenteral and Enteral Nutrition 18:531–533, 1994)
Digestion and Absorption of Tube‐Feeding Emulsions With Different Droplet Sizes and Compositions in the Rat
Authors: Borel Patrick , Armand Martine , Pasquier Berengere , Senft Michele , Dutot Guy , Melin Christian , Lafont Huguette , Lairon Denis
Published: May 2008

Assimilation of lipid nutrients depends on the efficiency of emulsified fat hydrolysis by digestive lipases. As shown in vitro, the activity of preduodenal and pancreatic lipases is governed by the physicochemical properties of emulsions. Thus the aim of this study was to evaluate in the rat how emulsions are digested and assimilated depending on their droplet size or solute composition. Fasted rats were intragastrically tube fed emulsions with different median droplet sizes (0.6 μm, fine; 22 μm, coarse) or solute composition (0.8 μm, complex fine) containing 14C‐triolein and 3 H‐cholesterol. Two and 5 hours after feeding, fat‐droplet size was measured in gastric and duodenal contents, and lipids were radioactively quantified in different compartments. In the stomach, the droplet size of the fine emulsions significantly increased to values (13 μm to 24 μm) comparable with those of the coarse emulsion (35 μm to 36 μm). In the duodenum, the droplet sizes of the three emulsions were in the range of 14 μm to 33 μm. After 2 hours, gastric triglyceride hydrolysis was significantly higher with the fine than with the coarse emulsion and was lower with the complex fine emulsion. Gastric emptying of fat was significantly different, with the following decreasing order: coarse, fine, and complex fine emulsion. In the small intestine, the fine and coarse emulsions were processed comparably, whereas the assimilation of the fine complex emulsion was significantly delayed. Calculations indicate that ingested fatty acids were distributed in the peripheral tissues at different rates with the same decreasing order. The fate of a lipophilic nutrient, cholesterol, was also markedly altered by the type of emulsion. These data support the concept that tube‐fed emulsions with different droplet sizes and solute composition are digested differently and thus are metabolized differently. (Jourual of Parenteral and Enteral Nutrition 18:534–543, 1994)
Oral Branched‐Chain Amino Acids Decrease Whole‐Body Proteolysis
Authors: Ferrando Arny A. , Williams Bradley D. , Stuart Charles A. , Lane Helen W. , Wolfe Robert R.
Published: May 2008

Background: This study reports the effects of ingesting branched‐chain amino acids (leucine, valine, and isoleucine) on protein metabolism in four men. Methods: To calculate leg protein synthesis and breakdown, we used a new model that utilized the infusion of L‐[ring‐13C6]phenylalanine and the sampling of the leg arterial‐venous difference and muscle biopsies. In addition, protein‐bound enrichments provided for the direct calculation of muscle fractional synthetic rate. Four control subjects ingested an equivalent amount of essential amino acids (threonine, methionine, and histidine) to discern the effects of branched‐chain amino acid nitrogen vs the effects of essential amino acid nitrogen. Each drink also included 50 g of carbohydrate. Results: Consumption of the branched‐chain and the essential amino acid solutions produced significant threefold and fourfold elevations in their respective arterial concentrations. Protein synthesis and breakdown were unaffected by branched‐chain amino acids, but they increased by 43% (p <.05) and 36% (p <.03), respectively, in the group consuming the essential amino acids. However, net leg balance of phenylalanine was unchanged by either drink. Direct measurement of protein synthesis by tracer incorporation into muscle protein (fractional synthetic rate) revealed no changes within or between drinks. Whole‐body phenylalanine flux was significantly suppressed by each solution but to a greater extent by the branched‐chain amino acids (15% and 20%, respectively) (p <.001). Conclusions: These results suggest that branched‐chain amino acid ingestion suppresses whole‐body proteolysis in tissues other than skeletal muscle in normal men. (Journal of Parenteral and Enteral Nutrition 19:47–54, 1995)
Oral Glutamine Decreases Bacterial Translocation and Improves Survival in Experimental Gut‐Origin Sepsis
Authors: Gianotti Luca , Alexander J. Wesley , Gennari Roberto , Pyles Tonyia , Babcock George F.
Published: May 2008

Background: Glutamine has been shown to be an important dietary component for the maintenance of gut metabolism. The purpose of this study was to assess the potential benefit of glutamine‐enriched diets on experimental gut‐derived sepsis. Methods: BALB/c mice were fed either 2% glutamine‐supplemented or 1% glycine‐supplemented (near‐isonitrogenous control) AIN‐76A diets. Control mice received either nonsupplemented AIN‐76A or regular Purina Rodent Laboratory Mouse Chow 5001 diets. After 10 days of feeding, the mice were transfused with allogeneic blood (from C3H/HeJ mice), and the feeding protocols were continued for an additional 5 days. The mice then underwent gavage with 1010 Escherichia coli labeled with either indium‐111 oxine or [14C]glucose followed immediately by a 20% burn injury. Some mice were observed 10 days postburn for survival rates. Others were killed 4 hours after burn, and the mesenteric lymph nodes, liver, and spleen were harvested to determine radionuclide and bacterial colony counts. The percentages of viable translocated E coli were also calculated. Results: Mice fed glutamine‐enriched diets had a lower degree of translocation (as measured by both radionuclide and bacterial counts) to the tissues than did the other groups and had an improvement in the ability to kill translocated E coli (as measured by the percentage of viable bacteria). Survival was significantly higher in the group fed 2% glutamine (81%) compared with the groups fed 1% glycine (36%), AIN‐76A (35%), and Purina Rodent Laboratory Mouse Chow 5001 (36%) diets (p <.004). Conclusions: Glutamine‐supplemented enteral diets may exert important benefits in preventing gut‐origin sepsis after trauma (Journal of Parenteral and Enteral Nutrition 19:69–74, 1995)