ISSN:0148-6071    

DOI:10.1177/014860719602000101

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

The clinical status of patients with acute renal failure (ARF) varies greatly. Some individuals have only mild or moderate ARF or may have only mild perturbations of their metabolic status. Other patients exhibit a severe reduction in renal function with oliguria or anuria. Depending upon their comorbid conditions, ARF patients may be among the most hypercatabolic patients in the hospital. Clinical trials have not clearly shown a beneficial effect of nutrition support on morbidity or mortality in patients with ARF, although limitations in sample size and experimental design and inclusion of patients with widely disparate clinical conditions may have contributed to the difficulty in demonstrating benefits. Several recent therapeutic approaches that have been studied either in experimental animals with ARF or in small numbers of humans with ARF hold promise for improving clinical outcome. Continuous arteriovenous or venovenous hemofiltration with or without dialysis is such a therapy. In comparison to intermittent hemodialysis this former treatment more safely removes large quantities of water and solutes from critically ill patients with unstable hemodynamics and allows them to receive rather large quantities of nutrients, including amino acids. Also promising are studies in experimental animals with ARF which indicate that several growth factors may accelerate the recovery of renal function. In rats with ARF, insulin‐like growth factor 1 both enhances recovery of renal function and suppresses their enhanced catabolism. For most patients with ARF requiring nutrition support, evidence suggests that both essential and nonessential amino acids should be employed. However, there appears to be a therapeutic role for small quantities of essential amino acids, without nonessential amino acids, in selected patients. Data support the importance of proactive measures to prevent fluid and electrolyte imbalances in patients with ARF.(Journal of Parenteral and Enteral Nutrition20:3–12, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000103

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:The 1995 A.S.P.E.N. Research Workshop was held at the annual meeting in Miami Beach, Florida, on January 15, 1995. The workshop focused on substrate metabolism in humans.Methods:State‐of‐the‐art presentations on the regulation of energy, carbohydrate, lipid, and protein metabolism during health and disease were made by the preeminant leaders in the field. The presentations concentrated onin vivostudies performed in humans and included both recently published and unpublished data.Results:Using sophisticated research methodology, such as nuclear magnetic resonance spectroscopy, compartmental modeling, stable isotope tracers, microdialysis, and abdominal vein catheterization, the investigators presented data that clarified unresolved issues, challenged many previously held dogmas, and raised new questions for future investigation in human intermediary metabolism.Conclusions:This workshop demonstrated thatin vivoinvestigation remains the best approach for providing physiologically relevant data in humans. An understanding of normal human physiology and the metabolic alterations caused by disease is critical for optimal nutritional and metabolic management of patients.(Journal of Parenteral and Enteral Nutrition20:13–19, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000113

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

ISSN:0148-6071    

DOI:10.1177/0148607196020001011

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:This two‐part study initially evaluated complications associated with catheters inserted via upper extremity veins. The second prospective phase compared thrombotic risk of peripheral catheter tipsvsa central vein terminus.Methods:Patients from public institutions with infectious diseases were observed throughout their inpatient and outpatient use of IV catheters. Seventy‐two and 39 patients enrolled in phase 1 and phase 2, respectively. Phase 1 consisted of prospective observations and analysis of complications and associated risk factors. Phase 2 randomized patients to a catheter tip location in the superior vena cava or the axillosubclavian‐innominate vein and compared the incidence of thrombosis, phlebitis, and infection.Results:In phase 1, there was an increased risk of thrombosis with peripheral tip localization (61%vs16%,p<.05). Phase 2 confirmed increased thrombosis with tips in the axillosubclavian‐innominate vein compared with the superior vena cava (60%vs21%,p<.05) with an improved survival for central tip catheters (p<.02). Catheters associated with thrombosis were more likely to become infected (r = 0.48,p<.02).Conclusions:The experience supports use of the long arm catheter as an effective device for parenteral therapy. A novel method for placing these catheters makes most patients candidates for this approach. Placing a long arm‐catheter's tip in the central venous circulation reduces the risk of thrombosis. A high incidence of tip misdirection indicates a need for radiographic confirmation before use.(Journal of Parenteral and Enteral Nutrition20:20–24, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000120

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:The effect of chronic parenteral infusions of either saline (S), dextrose (D), amino acids without glutamine (AA), or amino acids including glutamine dipeptides (AA+GLN) on interorgan movement of glutamine (GLN) and glutamate (GLU) after fasting was examined.Methods:Multicatheterized mongrel dogs were stressed by fasting for 4 days followed by a 4‐day IV infusion of either S (30 mL/h, n = 8), D (8.6 kcal/h, n = 8), isocaloric AA (8.3 g N/d, n = 7), or isocaloric AA+GLN (8.3 g N/d, 6.8 g GLN/d, n = 6). Hepatic and hindlimb blood flows were estimated, and net arterio‐venous balance measurements (μLmol/kg per minute) were made during the last 2 hours of infusion.Results:Arterial blood concentrations of GLU were 47 ± 6, 52 ± 3, 47 ± 5, and 62 ± 8 and of GLN were 587 ± 25, 548 ± 20, 423 ± 22 (p≤.05vsS), and 512 ± 59 μmol/L for S, D, AA, and AA+GLN, respectively. Slight GLU uptake and GLN release by the hindlimb were observed in all groups. Gut GLU production was ‐0.31 ± 0.06, ‐0.04 ± 0.07 (p≤.05vsS), ‐0.15 ± 0.05, and ‐0.14 ± 0.02 (p≤.05vsS), and gut GLN uptake was 0.64 ± 0.38, 1.54 ± 0.25, 0.80 ± 0.16, and 0.85 ± 0.11. Hepatic GLU uptake was 0.16 ± 0.06, 0.09 ± 0.05, 0,23 ± 0.06, and 0.43 ± 0.10 (p≤.05vsS). Net hepatic GLN balance was ‐0.06 ± 0.54, ‐0.77 ± 0.17, ‐0.21 ± 0.13, and 1.92 ± 0.39 (p≤.05 vs S).Conclusions:Neither hindlimb GLU uptake nor GLN release were influenced by nutrient infusion. Parenteral D blunted gut GLU release with no effect on gut GLN uptake. AA did not alter GLN or GLU balances in the organs measured. However, although AA+GLN infusion did not enhance gut GLN uptake, it did alter hepatic metabolism with a threefold increase in GLU uptake and a shift from net GLN equilibrium to GLN utilization. Thus, GLN administered parenterally after fasting was not directed preferentially for use by skeletal muscle or by gut tissues but rather was used extensively by the liver.(Journal of Parenteral and Enteral Nutrition20:25–30, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000105

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Although intolerance to nasogastric feeding is commonly observed after head injury, quantitative measurements of gastric emptying are lacking. Concepts about energy requirements are limited by the lack of long‐term measurements of total energy expenditure.Methods:Six male subjects with severe head injury had their gastric emptying measured by the phenol red technique. N and energy balances were measured by classic balance techniques, which included continuous indirect calorimetry for up to 24 hours (days 3 to 5). Measurements of body composition were made on days 3 to 5 and 12 to 19 (4 subjects only).Results:The subjects lost a mean of 9.8 kg of which 2.3 kg was estimated to be due to fat (equivalent to — 14 g N/d and —1690 kcal/d). On days 3 to 5, basal metabolic rate (BMR) was 130% to 135% of predicted. The low dietary intake (650 kcal and 4.2g N/d) was associated with negative energy (— 1710 ± 520 kcal/d) and N balances (‐19 ± 5 g N/d). Gastric emptying was delayed twofold (days 3 to 5) compared with controls (p0.5 mmol/L compared with control values of<0.2 mmol/L.Conclusions:The large negative energy balance in the subjects studied was largely due to the inadequate nasogastric feeding, which was associated with a twofold reduction in the rate of gastric emptying and frequent regurgitation of feed. The large negative N balance and the high contribution of protein oxidation to total energy expenditure (25% to 28%) was predominantly due to the injury sustained and immobility. An increase in BMR is not necessarily associated with increased total energy expenditure or energy requirements.(Journal of Parenteral and Enteral Nutrition20:31–37, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000131

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background :Dicarboxylic acids are water‐soluble, contrary to monocarboxylic acids, and have a metabolic pathway intermediate between those of lipids and carbohydrates. Our goal was to investigate the plasma turnover and oxidation rate of dodecanedioic acid (C12) in eight healthy male volunteers.Methods:A simultaneous infusion of both cold (0.24 mmol/ min corresponding to 0.396 kcal/min) and radiolabeled (1.62 μCi/min) C12 free acid was performed. Blood specimens were sampled over a period of 360 minutes, and 24‐hour urine samples were collected to measure the levels of C12 by high‐performance liquid chromatography and liquid scintillation. Indirect calorimetry was continuously performed, and expired14CO2was collected. Binding of C12 in human plasma was determined in separate experiments using equilibrium dialysis.Results:A linear one‐compartment model was used to describe the kinetics of labeled C12. Its volume of distribution was 139.02 ± 10.84 mL/kgbw(mean ± SE), and its plasma elimination constant was 0.01 ± 0.004 min−1. The 24‐hour urinary excretion of C12 was 3.14 ± 0.96 mmol, corresponding to about 7% of the administered dose. The amount of C12 oxidized, expressed as percent oxidation, was equal to 35.44 ± 1.64%. The mean basal value of npRQ (0.80 ± 0.006) significantly (p<.02) decreased during the infusion to 0.78 ± 0.01, which is a value close to that theoretically calculated (0.77). The oxidation of free fatty acids was significantly increased at the end of the C12 infusion, whereas the glucose oxidation was reduced to about 50%.Conclusions:The experimental data suggest that C12 might represent a fuel substrate immediately available for tissue energy requirements, because a relevant amount of C 12 is promptly oxidized. Its prompt oxidation and its conversion to succinic acid support the use of dodecanedioic acid in parenteral nutrition, especially in insulin‐resistance conditions in which glucose uptake and oxidation is impaired.(Journal of Parenteral and Enteral Nutrition20:38–42, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000138

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background :Dietary fish oil (FO) has been shown to modulate the immune system. The purpose of this study was to explore the effects of FO supplementation on the production of dienoic eicosanoids and cytokines in patients with human immunodeficiency virus (HIV) infection.Methods:This was a randomized, prospective, double‐blind study that included homosexual males with HIV infection. Patients were asked to consume voluntarily five food bars daily containing FO (n = 10) or safflower oil (SO) (n = 9) for 6 weeks. At baseline and week 6, plasma was obtained to measure incorporation of ω‐3 fatty acids. At baseline, week 3, and week 6, measurements were made of changes in dienoic eicosanoids and cytokines from lipopolysaccharide (LPS)‐stimulated peripheral blood mononuclear cells (PBMC) or spontaneously releasing cells.Results:In the FO group but not the SO group, there was increased incorporation of the ω‐3 fatty acid docosahexaenoic acid (DHA) into the phospholipids of the fatty acids of the plasma. In the FO group, there was a significant decrease (p =.01) in 6‐keto prostaglandin (PG) F1αreleased from PBMC. There was a significant increase (p =.01) in interleukin (IL)‐6 released from the PBMC in the FO group between baseline and week 3 and between week 3 and week 6. At week 6, there was significantly more IL‐6 (p =.01) released from the PBMC in the FO group compared with the SO group. There was no change in CD4cell counts by analysis of variance.Conclusions:The FO‐containing food bars were well tolerated and allowed incorporation of ω‐3 fatty acids to occur. Despite evidence of significant metabolic effects on eicosanoid and cytokine production, widespread clinical use of FO for HIV‐infected patients is not warranted without further study, particularly given the trend toward a decline in CD4cell numbers at this dose and with this type of fish oil.(Journal of Parenteral and Enteral Nutrition20:43–49, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000143

出版商:SAGE Publications    

年代:1996

数据来源: WILEY

摘要:

Background:Lipopolysaccharide (LPS), tumor necrosis factor‐α, (TNF), and glucocorticoids can modulate endothelial nitric oxide (NO) production. L‐Arginine is the exclusive precursor for NO biosynthesis, suggesting that NO generation and arginine transport are intimately linked.Methods:To further study this relationship, we examined the effects of LPS, TNF, and dexamethasone (DEX) on arginine uptake by rat lung microvascular endothelial cells. The transport of radiolabeled arginine was assayed in confluent cells grown in 24‐well plates.Results:The bulk (>90%) of arginine transport was mediated by the Na+‐independent carriers System y+and System b0,+. Arginine transport was stimulated independently by LPS and TNF, a response first observed at 10 hours. Together, both agents exerted an additive effect on carrier‐mediated uptake. The LPS‐ and TNFinduced increase in arginine transport activity was blocked by cycloheximide and actinomycin D, indicating the requirement for RNA and protein synthesis. The enhancement in transport activity was primarily due to an increase in Systems y+maximal transport capacity (Vmax) with no change in transporter affinity and little change in System b0,+activity. Treatment of cells with dexamethasone inhibited arginine transport activity in a time‐and dose‐dependent manner, an event that was abrogated by both actinomycin D and cycloheximide. The combination of DEX and LPS and TNF abrogated each other's antagonistic effects.Conclusions:These data indicate that LPS and TNF additively stimulate arginine transport in lung microvascular endothelial cells via a pathway that requiresde novoprotein synthesis (possibly of the transporter protein itself) and that this response is attenuated by DEX.(Journal of Parenteral and Enteral Nutrition20:50–55, 1996)

ISSN:0148-6071    

DOI:10.1177/014860719602000150

出版商:SAGE Publications    

年代:1996

数据来源: WILEY