Reducing parenteral energy and protein intake improves metabolic homeostasis after bone marrow transplantation

The purpose of this prospective study was to compare the metabolic effects of reducing parenteral energy and protein intake in bone-marrow-transplant (BMT) patients from 150% (hi-TPN group) to 100% (lo-TPN group) basal energy expenditure. Cytotoxic therapy was given on days 1-5, BMT on day 6, and TPN beginning on days 6 or 7. The lo-TPN group exhibited higher serum albumin (38 +/- 0.4 vs 32 +/- 0.4 g/L, P less than 0.01) but similar nitrogen balance (-83 +/- 8 vs -86 +/- 8 mg.kg-1.d-1, P greater than 0.05). Serum Na+ remained greater than 134 +/- 1 mmol/L in the lo-TPN group but fell to 127 +/- 1 mmol/L in the hi-TPN group (P less than 0.001) despite similar Na+ intakes and balances. Serum K+ remained less than 4.4 +/- 0.2 mmol/L in the lo-TPN group but rose to 5.1 +/- 0.1 mmol/L in the hi-TPN group (P less than 0.01) despite similar K+ intakes and balances. Delivering TPN at lower-than-normal rates after BMT appears to minimize Na+ and K+ disturbances and improve serum albumin concentrations without having any adverse effect on nitrogen balance.     

Alterations in hepatic mitochondrial function during total parenteral nutrition in immature rats

To evaluate the effects of total parenteral nutrition (TPN) on hepatic mitochondrial function in immature rats, changes in hepatic energy charge levels and oxidative phosphorylation rates of hepatic mitochondria were studied along with the examination of serum chemical test. Male Wistar rats weighing 30 to 45 g were used and randomized into TPN (n = 8), enteral (n = 7), and control groups (n = 8). Parenteral and enteral groups were fed with TPN solution containing 19.3% dextrose, 3.19% amino acids, 1.05% fat emulsion, minerals and vitamins, and the control group with rat chow. The number of calories per kilogram per day was 550 x 1/4 on the 1st day, 550 x 1/2 on the 2nd, 550 x 3/4 on the 3rd, and 550 x 1 on the 4th day, based on the body weight on the 1st day. After the 5th day, 550 Kcal/kg/day was given, based on the body weight of the respective day. After 13-day feeding, hepatic energy charge (EC), phosphorylation rate (PR) of hepatic mitochondria and serum chemical examination were carried out. EC was 0.871 +/- 0.016 in the control group, 0.830 +/- 0.019 in the enteral, and 0.785 +/- 0.011 in TPN group (p less than 0.001, compared with control group). PR was 138.9 +/- 1.9, 133.0 +/- 6.7, 111.0 +/- 4.3, respectively, (p less than 0.05, compared with control and enteral groups). There was no difference between the three groups on SGOT, SGPT, and total bilirubin. TPN group showed a deterioration of hepatic phosphorylation rate and energy charge in spite of normal serum transaminase levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Parenteral nutrition for marrow transplant recipients: evaluation of an increased nitrogen dose

The use of total parenteral nutrition in bone marrow transplant (BMT) recipients is well recognized. These patients as a result of treatment with chemotherapy and immunosuppressive agents undergo catabolic stress. The metabolic effect of an increased nitrogen dose during total parenteral nutrition (TPN) was studied in 28 BMT patients. Patients were given TPN formulas providing a nitrogen intake of either 267 +/- 44 mg of N/kg/d or 330 +/- 60 mg of N/kg/d. Total calories, nonprotein and protein, were held constant at 40 kcal/kg/d for all patients. Data was collected for three periods posttransplant beginning at 3 days posttransplant through day 16. Both study TPN formulas improved patient weight and TIBC values over baseline. Nitrogen balance (NB) values were not significantly different at any study period. However, an overall group effect favored the H-N formula (p less than 0.01). BMT patients undergo catabolic stress which was reflected by average values of 24-hour urine urea nitrogen increasing from 8.1 +/- 4 g/d at baseline to 19.8 +/- 7.2 g/d at period 3 (p less than 0.01). The H-N formula did not differentially increase blood urea nitrogen or serum creatinine levels. Metabolic cart measures also showed no increase in metabolic rate, oxygen consumption, carbon dioxide production, or percent contribution of protein to total metabolic expenditure. Providing a caloric intake of 40 kcal/kg/d was excessive, where 30 to 35 kcal/kg/d would meet metabolic demands. Pertinent clinical outcomes including length of stay, relapse rate, and survival were monitored, but no conclusions could be drawn in this study. The H-N formula was more effective in reducing loss of lean body mass without causing detrimental metabolic effects in BMT patients.     

Low serum selenium and glutathione peroxidase activity in patients receiving short-term total parenteral nutrition

Selenium status was determined in 15 consecutive postoperative patients receiving short-term total parenteral nutrition (TPN) using both serum selenium concentration and glutathione peroxidase (GSH-Px) activity as an indicator of body selenium status. The serum selenium concentration was significantly (p less than 0.001) lower in TPN patients (0.52 +/- 0.16 mumol/l, mean +/- SD) than in age- and sex-matched controls (1.08 +/- 0.17 mumol/l). Serum selenium in TPN patients ranged from 0.28 to 0.79 mumol/l and was associated with the duration of TPN. The lowest selenium values was found in patients who had received TPN over 3 weeks (0.35 +/- 0.06 mumol/l) as compared to patients receiving TPN for 1-3 weeks (0.61 +/- 0.13 mumol/l; p less than 0.01). Serum GSH-Px activity in TPN patients was also low (116 +/- 21 U/l) and ranged from 75 to 159 U/l. A significant positive correlation was found between serum selenium and GSH-Px activity (r = 0.520; p less than 0.05) whereas serum selenium and GSH-Px activity did not correlate significantly with liver function tests and body mass index. This study suggests that also short-term TPN patients may be at risk of selenium deficiency.     

Critically-ill patients receiving total parenteral nutrition show altered amikacin pharmacokinetics

The purpose of this clinical study was to characterise the kinetic behavior of amikacin in the parenterally-fed critically-ill adult patient. 22 critically-ill adult patients treated with amikacin (15.5 +/- 7.9 mg/kg/day) for severe gram-negative infections were enrolled into a non-randomised control trial. Malnourished patients were administered total parenteral nutrition (TPN, n = 11), while well-nourished patients received fluid therapy (FT, n = 11). Amikacin pharmacokinetic parameters were estimated by non-linear regression analysis, assuming a one-compartment model and central first-order elimination. Patients receiving TPN showed an expanded amikacin distribution volume (0.403 +/- 0.0961/kg vs. FT 0.298 +/- 0.083 l/kg, p < 0.05), and a tendency towards increased total body clearance (0.089 +/- 0.029 l/kg/h vs. FT 0.069 +/- 0.0201/kg/h, p = 0.09). TPN produced lower peak concentrations (19.3 +/- 3.1 mcg/ml vs. 23.1 +/- 3.5 mcg/ml, p < 0.05), but had no significant influence on trough concentrations (p = 0.56). Patients on TPN also showed increased body temperature (p < 0.05) and fluid intake (p < 0.05), and decreased hematocrit (p < 0.05). Stress, malnutrition, parenteral nutrition itself, fluid and osmotic overload, and fever often occur concurrently in parenterally-fed patients and appear to produce lower amikacin serum levels. Consequently, critically-ill patients receiving TPN need higher amikacin doses and individualised treatment by monitoring serum concentrations, to ensure optimal therapeutic response.     

Glucose-based versus fat-based total parenteral nutrition (TPN): effects on hepatic function in septic patients complicated with cholestatic jaundice

A prospective study of two types of total parenteral nutrition (TPN) was carried out in 34 patients suffering from sepsis and complicated liver dysfunction. Group 1 (18 patients) received non-protein energy as glucose plus fat emulsion in a caloric ratio of 19:1, while group 2 (16 patients) received the same energy intake but with a ratio of 1:1. Group 1 exhibited higher levels of bilirubin and alkaline phosphatase with values of 93.5 +/- 25.5 mumol/l and 160 +/- 30 IU/l respectively compared to Group 2, in which the corresponding values were 81.6 +/- 32.3 mumol/l and 120 +/- 10 IU/l (p < 0.05). On the other hand, group 1 had lower levels of serum albumin and serum transferrin with values 25 +/- 1.3 g/l and 40 +/- 20% of normal, compared to group 2 in whom the corresponding values were 28 +/- 8 g/l and 48 +/- 30% of normal (p < 0.05). There were no differences between the two groups, in the absolute number of T-lymphocytes and in transaminase levels. In sepsis complicated by liver dysfunction a 50:50 glucose: fat regimen caused less disturbance of liver function than one consisting almost entirely of glucose.     

The effects of different intravenous feeding regimens on the rates of synthesis of alpha1-antitrypsin after surgery

The effects of two nutritional regimens on the synthesis of alpha-1 antitrypsin were investigated postoperatively in gynaecological cancer patients. Total parenteral nutrition (TPN) or a hypocaloric amino acid mixture was administered on the day of surgery and continued for 3 days. The rate of synthesis of alpha-1 antitrypsin was estimated by a computer model from serial plasma concentrations of this protein and a reference protein, albumin. The hypocaloric amino acid mixture resulted in a more negative nitrogen balance than that produced during administration of TPN containing the same amount of nitrogen but more non-protein energy. Urinary excretion of 3-methylhistidine was significantly greater (p = 0.017) in the hypocaloric amino acid group (350 +/- 40 mumol/day; mean +/- SE) on the third postoperative day, as compared to the TPN group (240 +/- 20 mumol/day). In spite of this the synthesis of alpha-1 antitrypsin was apparently greater in the hypocaloric amino acid than in the TPN group. The accumulated plasma appearance rate of alpha-1 antitrypsin was significantly higher (p = 0.0465) in HAA group, at 70 h it was 490 +/- 40 compared to 400 +/- 20 times the pre-operative synthesis in the TPN group.     

Liver composition and histology in growing infant miniature pigs given different total parenteral nutrition fuel mixes

Although young infants are at greater risk for total parenteral nutrition (TPN)-related liver disease than adults, previous studies on the effect of the TPN energy source on the development of hepatic steatosis have been carried out in adult rats and adult humans. We studied the effect of a glucose and a glucose/fat TPN energy regimen on hepatic chemical composition and the development of steatosis in newborn miniature pigs. Twenty miniature pigs were randomized at 10 days of age to receive a TPN regimen which utilized either glucose (group A) or glucose/fat (group B) as the non-nitrogen energy source. After 8 days, blood was drawn for insulin, glucagon, SGPT, albumin, and bilirubin determinations. Samples of liver were obtained at 9 days. Plasma insulin levels were significantly higher and glucagon levels lower in group A piglets than in those in group B. Normal values were obtained for SGPT, albumin, and bilirubin, and no differences were found between groups. Chemical analysis of the livers revealed no differences between groups in the concentrations of glycogen, fat, protein, DNA, and RNA. Group A animals had significantly higher concentrations of water than group B (group A: 0.75 +/- 0.01 liter/kg; group B: 0.74 +/- 0.01; p less than 0.03). A significant correlation was found in group B between the plasma insulin/glucagon ratio and the hepatic glycogen concentration (r = 0.73, p less than 0.05). Group A animals had fat vacuoles in centrilobular hepatocytes, in contrast with group B animals who had visible fat only in Kupffer cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Liver function tests abnormalities in patients with inflammatory bowel disease receiving artificial nutrition: a prospective randomized study of total enteral nutrition vs total parenteral nutrition

Liver and biliary abnormalities are well-known complications of inflammatory bowel disease (IBD). It has been suggested that using total parenteral nutrition (TPN) may further impair liver function in these patients; this seems not to be so with total enteral nutrition (TEN). However, prospective trials comparing the incidence of liver function test (LFT) abnormalities with either TPN or TEN have not been carried out. Twenty-nine IBD inpatients with normal LFT, randomized to receive either TEN with a polymeric diet or isocaloric, isonitrogenous "all-in-one" TPN because of protein-energy malnutrition and/or severe disease, were included in the study. Sixteen patients (five with ulcerative colitis and 11 with Crohn's disease) received TEN, and 13 patients (eight ulcerative colitis and five Crohn's disease) were on TPN. All patients were on systemic steroids, and nine of them were on oral metronidazole. Both groups were homogeneous regarding age, sex, diagnosis, disease activity, nutritional status, daily nutrient supply, and days on artificial nutrition. Serum albumin levels significantly increased with TEN (32 +/- 1 to 38.2 +/- 1.6 g/liter, p less than 0.01), but not with TPN (32.1 +/- 2.2 to 33.9 +/- 1.4 g/liter, NS). Clinical improvement occurred in both groups of patients as shown by the change in the disease activity indexes. In all cases, measurements of serum alkaline phosphatase, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase were performed weekly. There were no significant differences in the initial LFT between both groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum vitamin A and E concentrations in pediatric total parenteral nutrition patients

There is uncertainty as to optimal doses of fat soluble vitamins required by pediatric total parenteral nutrition (TPN) patients. We compared serum vitamin A (A) and E (E) concentrations analyzed by HPLC in chronic (greater than 2 weeks) TPN patients aged 1 month to 12 years to values obtained in out-patient surgery patients of the same age. TPN patients received 1500 micrograms of retinol and 2.5 IU of E as alpha-tocopheryl acetate (2.5 ml LyphoMed Multi Vitamin Concentrate). These doses were 214% of the recommended dose of A and 36% for E. Oral intake was minimal in most patients. The results of our study revealed a mean serum A level for TPN patients (N = 29) of 26.0 +/- 15.0 (SD) micrograms/dl vs 25.0 +/- 10.0 (SD) micrograms/dl in controls (N = 52). Mean serum E was 0.63 +/- 0.24 (SD) mg/dl vs 0.89 +/- 0.31 (SD) mg/dl for TPN patients and controls, respectively. There was no consistent trend related to duration of TPN for 23 patients with serial values. Seven (24%) TPN patients had serum A greater than mean + 2 SD of control (p less than 0.01). No values were less than mean - 2 SD. Infants on TPN had a significantly lower mean serum A (22.3 +/- 10.9 micrograms/dl) than TPN patients greater than 1 year of age (34.1 +/- 16.0 micrograms/dl; p less than 0.001). Fifty-two percent of TPN patients vs 26% of control had serum A less than 20 micrograms/dl (p greater than 0.1). For E, one patient had a high value and two patients low values relative to control.(ABSTRACT TRUNCATED AT 250 WORDS)     

Choline deficiency causes reversible hepatic abnormalities in patients receiving parenteral nutrition: proof of a human choline requirement: a placebo-controlled trial

BACKGROUND: Previous studies have shown that plasma free choline concentrations are significantly decreased in many long-term home total parenteral nutrition (TPN) patients. Furthermore, low choline status has been associated with both hepatic morphologic and hepatic aminotransferase abnormalities. A preliminary pilot study suggested choline-supplemented TPN may be useful in reversal of these hepatic abnormalities. METHODS: Fifteen patients (10 M, 5 F) who had required TPN for > or =80% of their nutritional needs were randomized to receive their usual TPN (n = 8), or TPN to which 2 g choline chloride had been added (n = 7) for 24 weeks. Baseline demographic data were similar between groups. Patients had CT scans of the liver and spleen, and blood for plasma free and phospholipid-bound choline, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, gamma glutamyl transferase (GGT), bilirubin, serum lipids, complete blood count (CBC), and chemistry profile obtained at baseline, and weeks 2, 4, 6, 12, 16, 20, 24, and 34. CT scans were analyzed for Hounsfield unit (HU) densities. RESULTS: There were no significant differences in any measured parameters after 2 weeks. However, at 4 weeks, a significant difference in liver HU between groups was observed (13.3+/-5.0 HU [choline] vs 5.8+/-5.2 HU [placebo], p = .04). This significant trend continued through week 24. Recurrent hepatic steatosis and decreased HU were observed at week 34, 10 weeks after choline supplementation had been discontinued. A significant increase in the liver-spleen differential HU was also observed in the choline group (10.6+/-6.2 HU [choline] vs 1.3+/-3.3 HU [placebo], p = .01). Serum ALT decreased significantly (p = .01 to .05) in the choline group vs placebo at weeks 6,12, 20, and 24. Serum AST was significantly decreased in the choline group by week 24 (p = .02). The serum alkaline phosphatase was significantly reduced in the choline group at weeks 2, 12, 20, 24, and 34 (p = .02 to 0.07). Total bilirubin was normal in these patients and remained unchanged during the study. Serum GGT tended to decrease more in the choline group, but the greater decrease was not statistically significant. CONCLUSIONS: Choline deficiency is a significant contributor to the development of TPN-associated liver disease. The data suggest choline is a required nutrient for long-term home TPN patients.     

Plasma and erythrocyte essential fatty acids during total parenteral nutrition in infants: effects of a cutaneous supply

In order to prevent essential fatty acid (EFA) deficiency induced by fat-free total parenteral nutrition (TPN), 10 infants on TPN were rubbed three times daily for 20 days using oenethera oil (80% EFA). Total EFA amount provided cutaneously was 1900 mg/kg/d. Plasma and red blood cells phospholipids were determined on days 1 and 20 in these 10 treated and six untreated infants on TPN and compared with those of normal control infants. On day 1, plasma nonessential FA including 20:3 n-9(p less than 0.01) were increased in both TPN groups while 18:2 n-6 and 18:3 n-3 (p less than 0.001 and p less than 0.01) were decreased. On the 20th day, EFA deficiency had worsened with a decrease in plasma level of 20:4 n-6 (p less than 0.02) and a higher than normal triene/tetraene ratio : 3.4 +/- 1.1 and 2.3 +/- 0.6 vs 0.1 +/- 0.1 (p less than 0.02). As for red blood cells phospholipids, 16:0 was increased and 18:2 n-6 and 20:3 n-6 were decreased (p less than 0.05) on day 1. On day 20, these FA were more abnormal while 20:3 n-9 became significantly increased (p less than 0.05). No difference was observed between the TPN groups at any time. These results show that cutaneous application of large amounts of EFA-rich oil is unable to prevent or cure TPN induced EFA deficiency.     

Plasma ammonia levels in preterm infants receiving parenteral nutrition with crystalline L-amino acids

In order to investigate the severity and incidence of hyperammonemia in preterm infants receiving total parenteral nutrition (TPN) with crystalline L-amino acids having high arginine content (Travasol), we determined the plasma ammonia (PA) levels in a group of 29 preterm infants on TPN, weekly and 1 wk posttherapy. Their mean gestational age was 29.9 +/- 2.6 wk and mean birth weight 1208 +/- 262 g. Thirty five blood samples obtained from 15 preterm infants not on TPN with mean gestational age 32.2 +/- 1.9 wk and a birth weight of 1495 +/- 161 g served as a control. In the parenteral nutrition group the mean PA level (140 +/- 58 micrograms/100 ml) was significantly higher (p less than 0.001) than that in the same group one week post TPN (97 +/- 34 micrograms/100 ml) and in the control group (86 +/- 35 micrograms/100 ml). The incidence of hyperammonemia (greater than 160 micrograms/100 ml) was 30% in the TPN group versus 3% in the controls (p less than 0.01). Maximal PA level during that treatment was 405 versus 216 micrograms/100 ml 1 wk post-TPN versus 163 micrograms/100 ml in the controls. The data show a significant increase in PA levels in preterm infants receiving TPN with Travasol, possibly because of its high glycine content.     

Beta-glucuronidase and hyperbilirubinemia in breast-fed versus formula-fed babies.

Breast milk and formula milk and the corresponding serum samples from 20 breast-fed babies, 20 formula-fed babies, and their mothers were examined at 3 days of age for beta-glucuronidase enzyme. Serum indirect bilirubin levels were also examined for all the infants. Serum indirect bilirubin concentrations were significantly higher (p < 0.001) in breast-fed (4.87 +/- 2.4 mg/dl) than in formula-fed infants (1.04 +/- 0.5 mg/dl). beta-glucuronidase activity in formula milk was negligible, while that in human milk was considerable (468.26 +/- 220.8 Sigma units/ml) and was correlated (p < 0.05) with that in the serum of the breast-fed (66.13 +/- 18.1 Sigma units/ml) than in formula fed infants (52.08 +/- 11.9 Sigma units/ml) and a significant (p < 0.05) correlation was found between its serum level and serum indirect bilirubin in both breast and formula fed infants. Also in breast-fed infants serum bilirubin concentrations were related to beta-glucuronidase activity in breast milk (p < 0.05): Breast milk beta-glucuronidase--by facilitating intestinal reabsorption of bilirubin--seems to be an important factor in the neonatal hyperbilirubinemia of breast-fed babies.     

The C-terminal heptapeptide of bombesin reduces the deleterious effect of total parenteral nutrition (TPN) on gut-associated lymphoid tissue (GALT) mass but not intestinal immunoglobulin A in vivo

BACKGROUND: Bombesin, the amphibian analog of mammalian gastrin-releasing peptide, reverses total parenteral nutrition (TPN)-induced atrophy of gut-associated lymphoid tissue and increases intestinal and respiratory immunoglobulin A (IgA) levels. Structure-activity studies suggested that the biologically active portion of bombesin is a C-terminal heptapeptide (7AA). This study investigates the effect of 7AA on lymphocytes counts of the Peyer's patches (PP), the lamina propria (LP) and the intraepithelial layer (IE). METHODS: Forty-eight male mice were randomized to receive chow (n = 13), TPN only (n = 9), TPN + 15 microg 7AA 3 times per day (n = 13) or TPN + 150 microg 7AA 3 times per day (n = 13). After 5 days of feeding, PP, LP, and IE lymphocytes were determined. Intestinal IgA levels were measured with ELISA. Groups were compared with ANOVA. RESULTS: All TPN-fed mice lost more weight than mice fed chow (p < .04). Lymphocyte counts in PP, LP, and IE were significantly lower in the TPN group than in the 3 other groups but did not differ between the groups fed chow, TPN + 15 microg 7AA 3 times per day, or TPN + 150 microg 7AA 3 times per day. Intestinal IgA levels were higher in chow-fed mice (148.4 +/- 16.9) than in mice fed TPN (98.4 +/- 14.0, p = .008), TPN + 15 microg 7AA 3 times per day (96.9 +/- 7.7, p = .003) or TPN + 150 microg 7AA 3 times per day (87.3 +/- 6.7, p = .001). CONCLUSIONS: The C-terminal heptapeptide of bombesin prevented the TPN-induced decrease in intestinal lymphocyte populations but not the reduction in intestinal IgA levels.     

Effects of medium-chain and long-chain triacylglycerols in pediatric surgical patients

Medium-chain triacylglycerols (MCTs) have been shown to provide better nutritional support than long-chain triacylglycerols (LCTs). This study compares the efficacy of MCT combined with LCT with LCT alone in pediatric patients with surgical stress. Two groups of patients (n = 19 in each) received equivalent amounts of glucose (12 g. kg. d) and amino acids (2 g. kg. d), but one group received 10% Lipofundin MCT/LCT and the other received 10% LCT (1.5 g. kg. d) in a randomized study. Total parenteral nutrition (TPN) was given for 14 d. Blood and urine samples were collected before and after TPN administration for determination of various biochemical parameters. Indirect calorimetry was also performed to determine respiratory quotients and fuel utilization. After 14 d of TPN in the MCT/LCT group, there was a significantly higher blood lymphocyte percentage, a decreasing tendency of serum asparate aminotransferase and of total and direct bilirubin (P < 0.05). These changes were not observed in the LCT group. A significantly better nitrogen balance and a higher ketogenesis from day 3 were observed in the MCT/LCT group. The MCT/LCT group showed a more marked increased utilization of fat than the LCT group, whereas carbohydrate oxidation was less in the MCT/LCT group than in the LCT group (P < 0.05). In children after surgery, MCT/LCT is more protein sparing and induces a better immune response when compared with LCT-containing lipid emulsion. A TPN regimen containing MCT/LCT is likely to result in rapid oxidation of fats for energy without compromising the respiratory system.     

Continuous nasoenteral feeding: inverse relation between infusion rate and serum levels of bilirubin

The relation between nasoenteric formula caloric infusion rate and the serum bilirubin level was examined in 15 healthy subjects. The study protocol spanned 3 days and included fasting studies on day 1, continuous maintenance nasogastric feeding of a formula diet on day 2, and continuous feeding at a rate twice the maintenance level on day 3. Blood studies were performed in the early morning of each day. Fifteen subjects underwent the fasting measurements and the maintenance infusion, while 11 underwent all 3 days of the protocol. With the maintenance infusion serum bilirubin fell from the fasting value of (X +/- SD) 0.77 +/- 0.53 to 0.63 +/- 0.49 mg/dl for a reduction of 18% (p less than 0.05). For the subgroup of 11 subjects receiving two levels of formula infusion, fasting and maintenance serum bilirubin levels were 0.81 +/- 0.57 and 0.65 +/- 0.47 mg/dl, respectively, (p less than 0.05). With the twice maintenance infusion the plasma bilirubin decreased further to 0.46 +/- 0.29 mg/dl, a decrement of 43% relative to fasting (p less than 0.01). No other significant changes were detected during the protocol in the standard blood chemical and hematologic studies. Thus, the serum level of bilirubin is inversely related to the formula caloric infusion rate during continuous nasoenteric feeding.     

Long-term parenteral nutrition in unrestrained nonhuman primates: an experimental model

A freely mobile jacket and tether system was developed for the investigation of total parenteral nutrition (TPN)-induced metabolic bone disease and complications of prolonged TPN in 12 Macaca fascicularis nonhuman primates. The animals received TPN for 49 +/- 7 d (means +/- SEM), providing 82 +/- 2 kcal.kg-1.d-1. Serum glucose increased from 3.6 +/- 0.2 mmol/L at baseline to 8.3 +/- 1.9 mmol/L (p less than 0.01) during TPN, and serum albumin decreased from 38 +/- 1 g/L at baseline to 29 +/- 1 g/L (p less than 0.001) during 2.75% amino acid TPN and 30 +/- 2 g/L (p less than 0.01) during 5% amino acid TPN infusion. No significant changes were seen in serum prealbumin, total protein, bilirubin, alanine aminotransferase, and 5'-nucleotidase during TPN infusion. Major complications included catheter sepsis, hyperglycemia, diarrhea, and premature death in six animals. Thus, metabolic complications of prolonged TPN support may be investigated in a freely mobile nonhuman primate.     

Effects of prolonged, purine-free total parenteral and enteral nutrition on urate homeostasis in man

The influence on human urate homeostasis of prolonged, totally purine-free nutritional support, using total parenteral (TPN) or elemental enteral (EN) nutrition, is not well known. In a prospective study, we measured weekly serum uric acid, renal urate excretion and clearance, together with parameters of hydration, in 58 normally hydrated patients receiving prolonged (15 to 170 days) purine-free TPN (30 patients) or EN (28 patients) for various gastrointestinal disorders. A marked, early and sustained decrease (p less than 0.001) in serum uric acid was observed in TPN (155 +/- 9 mumol/l at day 7 versus 318 +/- 13 mumol/l before nutrition, mean +/- SEM) as well as in EN patients (192 +/- 11 mumol/l at day 7 versus 320 +/- 16 mumol/l before nutrition), together with a significant (p less than 0.01) rise in renal urate clearance. The urate clearance/glomerular filtration rate ratio increased significantly, while there was no significant change in natremia or plasma osmolarity. Serum urate and urate clearance returned to normal within 8 days of refeeding with a normally purine-containing diet. Replacement of TPN by EN or vice versa, or substitution of glucose by fructose resulted in no change in hypouricemia. A 4-day oral supply of purines (125 mg/day) in EN patients was associated with a 53% rise (p less than 0.01) in serum urate. We conclude that prolonged, purine-free TPN and elemental EN are a new cause of marked hypouricemia which is mainly due to increased urate clearance, the mechanism of the latter is still poorly known, but is not related to extracellular volume expansion.