The Combined Effects of Infection and Malnutrition on Protein Metabolism in Children

1983 ◽  
Vol 65 (3) ◽  
pp. 313-324 ◽  
Author(s):  
A. M. Tomkins ◽  
P. J. Garlick ◽  
W. N. Schofield ◽  
J. C. Waterlow
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Group Iv ◽  
Nitrogen Excretion ◽  
Whole Body ◽  
Body Protein ◽  
Group Iii ◽  
Group I ◽  
Urinary Nitrogen Excretion ◽  
Weight For Age

1. Twenty-two children were studied as in-patients at a Nigerian Hospital. 2. They were divided into four groups on the basis of weight for age: I, adequately nourished, acutely infected; II, moderately under weight, acutely infected; III, malnourished, chronically infected; IV, malnourished, uninfected. 3. Urinary nitrogen excretion was highest in group I and lowest in groups III and IV. Urinary creatinine was highest in group I, but did not differ significantly in groups II, III and IV. The excretion of 3-methylhistidine closely paralleled that of creatinine. It is suggested that the high rates of creatinine and methylhistidine excretion in group I resulted in part from destruction of muscle. 4. Rates of whole body protein turnover were measured by administration of a single dose of [15N]glycine with measurement of the excretion of 15N in urinary NH3 for the next 9 h. 5. Rates of protein synthesis and breakdown were very high in infected children of groups I and II. Although rates were lower in the malnourished groups, in infected children of group III they were nearly twice as high as in the uninfected group IV. The net balance of protein (synthesis minus breakdown) was negative in group I, less negative in group II, zero in group III and positive in group IV. 6. Repeat measurements in group I during recovery from infection showed a decline in rates of excretion of nitrogen, creatinine and 3-methylhistidine. Rates of protein synthesis and breakdown declined and the protein balance became less negative, but these changes were not statistically significant. 7. Multiple regression analysis of the results of all groups taken together showed independent contributions to rates of protein metabolism from infection and nutritional state, especially plasma albumin. 8. It was concluded that infection caused a rise in protein breakdown which was larger than the concomitant rise in synthesis, leading to net loss of protein, and that these responses were reduced by malnutrition.

scholarly journals Monoacetoacetin and protein metabolism during parenteral nutrition in burned rats

1985 ◽  
Vol 226 (1) ◽  
pp. 43-50 ◽  
Author(s):  
A Maiz ◽  
L L Moldawer ◽  
B R Bistrian ◽  
R H Birkhahn ◽  
C L Long ◽  
...  
Keyword(s):  
Energy Source ◽  
Ketone Bodies ◽  
Group Iv ◽  
Nitrogen Excretion ◽  
Whole Body ◽  
Protein Breakdown ◽  
Body Protein ◽  
Group Iii ◽  
Protein Energy ◽  
Group I

The effect of intravenous infusion of monoacetoacetin (glycerol monoacetoacetate) as a non-protein energy source was evaluated in burned rats. During 3 days of parenteral nutrition, in which animals received 14 g of amino acids/kg body wt. per day exclusively (group I) or with the addition of isoenergetic amounts (523 kJ/kg per day) of dextrose (group II), a 1:1 mixture of dextrose and monoacetoacetin (group III) or monoacetoacetin (group IV), significant decreases in urinary nitrogen excretion and whole-body leucine oxidation were observed in the three groups given additional non-protein energy as compared with group I. Serum ketone bodies (acetoacetate and 3-hydroxybutyrate) were decreased in rats given dextrose, whereas glucose and insulin increased significantly. Monoacetoacetin-infused animals (group IV) had high concentrations of ketone bodies without changes in glucose and insulin, whereas animals infused with both monoacetoacetin and glucose (group III) showed intermediate values. On day 4 of nutritional support, whole-body L-leucine kinetics were measured by using a constant infusion of L-[1-14C]leucine. In comparison with group I, the addition of dextrose or monoacetoacetin produced a significant decrease in plasma leucine appearance and release from whole-body protein breakdown. Gastrocnemius-muscle protein-synthesis rates were also higher in the three groups receiving additional non-protein energy. These findings suggest that monoacetoacetin can effectively replace dextrose as an intravenous energy source in stressed rats. Both fuels are similar in decreasing weight loss, nitrogen excretion, leucine release from whole-body protein breakdown and oxidation, in spite of differences in energy substrate and insulin concentrations.

Whole body protein synthesis in healthy adult humans: 13CO2 technique vs. plasma precursor approach

1995 ◽  
Vol 268 (1) ◽  
pp. E174-E184 ◽  
Author(s):  
A. E. el-Khoury ◽  
M. Sanchez ◽  
N. K. Fukagawa ◽  
V. R. Young
Keyword(s):  
Protein Synthesis ◽  
Healthy Adult ◽  
Physiological State ◽  
Nitrogen Excretion ◽  
Whole Body ◽  
Body Protein ◽  
Adult Humans ◽  
Pool Model ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

Different methods for the estimation of whole body protein synthesis (PS) in healthy adult humans were simultaneously compared in seven young adult subjects (6 males, 1 female) fed for 6 days a diet providing 1 g protein.kg-1.day-1 and approximately 188 kJ.kg-1.day-1. A 24-h intravenous tracer study with L-[1-13C]leucine was performed starting at 6 P.M. on day 6. During fasted (6 h) and fed (6 h) steady states, PS was estimated using an approach based on 13CO2 excretion (PSexcr) and on urinary nitrogen excretion data (corrected for changes in body urea pool). Simultaneously, we used the conventional two-pool model and plasma [13C]ketoisocaproate enrichment for estimating PS. The latter mean estimates of PS were significantly higher than PSexcr during fasting [861 +/- 58 (SD) vs. 663 +/- 160 mg protein.kg-1.6 h-1; P < 0.01] and feeding (985 +/- 63 vs. 779 +/- 127 mg protein.kg-1.6 h-1; P < 0.01) and were much less variable. In hourly small-meal feeding, urinary nitrogen excretion was not a reliable index of body protein oxidation when measured over short periods of 6 h, thereby introducing a lack of precision in PSexcr. We suggest that application of the 13CO2 technique to measure PS in humans is limited by the need for relatively prolonged experimental periods of urine collection and tracer infusion within a given physiological state.

scholarly journals Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects

2021 ◽  
pp. 1-9
Author(s):  
Jorn Trommelen ◽  
Andrew M. Holwerda ◽  
Philippe J. M. Pinckaers ◽  
Luc J. C. van Loon
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Dietary Protein ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Human Subjects ◽  
Whole Body ◽  
Body Protein

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

Enhancement of tumor proteolysis by TNF-alpha: correlation of in vivo isotope estimates with growth

1991 ◽  
Vol 261 (1) ◽  
pp. R106-R116
Author(s):  
N. W. Istfan ◽  
P. R. Ling ◽  
G. L. Blackburn ◽  
B. R. Bistrian
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Whole Body ◽  
Independent Effect ◽  
Yoshida Sarcoma ◽  
Protein Breakdown ◽  
Body Protein ◽  
Breakdown Rates ◽  
Made In

To evaluate the accuracy of in vivo estimates of protein synthesis and breakdown, measurements of plasma and tissue leucine kinetics were made in rat tumor tissues at different conditions of growth by use of constant intravenous infusion of [14C]leucine. These measurements were made in Yoshida sarcoma tumors on days 10 and 13 after implantation, with and without tumor necrosis factor (TNF) infusion and on day 10 in Walker-256 carcinosarcoma. Expressed as micromoles of leucine per gram tissue, tumor protein breakdown increased (P less than 0.01) from 0.32 +/- 0.02 to 0.52 +/- 0.09 (SE) mumol/h, with progress of the Yoshida sarcoma tumor between days 10 and 13 after implantation. Similarly, TNF increased tumor proteolysis on day 10 (0.43 +/- 0.03 mumol.h-1.g-1, P less than 0.05 vs. day 10 control) but not on day 13 after implantation of the Yoshida tumor. Estimates of growth derived from the difference between protein synthesis and breakdown rates were not statistically different from those based on actual tumor volume changes in both tumor models. However, estimates of “whole body” protein metabolism (plasma leucine flux) were not affected either by tumor aging or by treatment with TNF. This study shows that in vivo estimates of tissue protein metabolism based on our [14C]leucine constant infusion model closely reflect the growth characteristic of that tissue. A cytotoxic perfusion-independent effect for intravenous TNF on growing tumor tissue is demonstrable as increased protein breakdown. Furthermore, the commonly used concept of whole body protein metabolism, derived solely from tracer dilution in plasma, is an oversimplification.

scholarly journals The effect of a high dose of 3-hydroxy-3-methylbutyrate on protein metabolism in growing lambs

1997 ◽  
Vol 77 (6) ◽  
pp. 885-896 ◽  
Author(s):  
Isabelle Papet ◽  
Piotr Ostaszewski ◽  
Francoise Glomot ◽  
Christiane Obled ◽  
Magali Faure ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Protein Metabolism ◽  
Free Amino ◽  
Skeletal Muscles ◽  
Whole Body ◽  
Control Group ◽  
High Dose ◽  
Body Protein

AbstractThe effect of a high dose of 3-hydroxy-3-methylbutyrate (HMB, a leucine catabolite) on protein metabolism was investigated in growing male lambs fed on hay and concentrate. Concentrate was supplemented with either Ca(HMB)2 (4g/kg) or Ca(C03)2 in experimental (HMB) and control groups respectively. Both groups consisted of six 2-month old lambs. Three complementary methods to study protein metabolism were carried out consecutively 2·5 months after beginning the dietary treatment: whole body phenylalanine fluxes, postprandial plasma free amino acid time course and fractional rates of protein synthesis in skeletal muscles. Feeding a high dose of HMB led to a significant increase in some plasma free amino acids compared with controls. Total, oxidative and non-oxidative phenylalanine fluxes were not modified by dietary HMB supplementation. Similarly, an acute infusion of HMB, in the control group, did not change these fluxes. In skeletal muscles, fractional rates of protein synthesis were not affected by long-term dietary supplementation with HMB. Taken together our results showed that administration of a high dose of HMB to lambs was able to modify plasma free amino acid pattern without any effect on whole-body protein turnover and skeletal muscle protein synthesis

Effect of spaceflight on human protein metabolism

1993 ◽  
Vol 264 (5) ◽  
pp. E824-E828 ◽  
Author(s):  
T. P. Stein ◽  
M. J. Leskiw ◽  
M. D. Schluter
Keyword(s):  
Protein Synthesis ◽  
Nitrogen Balance ◽  
Protein Metabolism ◽  
Space Shuttle ◽  
Single Pulse ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Body Protein ◽  
Space Shuttle Columbia

Nitrogen balance and the whole body protein synthesis rate were measured before, during, and after a 9.5-day spaceflight mission on the space shuttle Columbia. Protein synthesis was measured by the single-pulse [15N]glycine method. Determinations were made 56, 26, and 18 days preflight, on flight days 2 and 8, and on days 0, 6, 14, and 45 postflight. We conclude that nitrogen balance was decreased during spaceflight. The decrease in nitrogen balance was greatest on the 1st day when food intake was reduced and again toward the end of the mission. An approximately 30% increase in protein synthesis above the preflight baseline was found for flight day 8 for all 6 subjects (P < 0.05), indicating that the astronauts showed a stress response to spaceflight.

Whole body protein metabolism and resting energy expenditure in pregnant Gambian women

1992 ◽  
Vol 263 (4) ◽  
pp. E624-E631 ◽  
Author(s):  
L. Willommet ◽  
Y. Schutz ◽  
R. Whitehead ◽  
E. Jequier ◽  
E. B. Fern
Keyword(s):  
Protein Synthesis ◽  
Energy Expenditure ◽  
Protein Metabolism ◽  
Resting Energy Expenditure ◽  
First Trimester ◽  
Significant Rise ◽  
Whole Body ◽  
Body Protein ◽  
Fed State ◽  
Resting Energy

Whole body protein metabolism and resting energy expenditure (REE) were measured at 11, 23, and 33 wk of pregnancy in nine pregnant (not malnourished) Gambian women and in eight matched nonpregnant nonlactating (NPNL) matched controls. Rates of whole body nitrogen flux, protein synthesis, and protein breakdown were determined in the fed state from the level of isotope enrichment of urinary urea and ammonia during a period of 9 h after a single oral dose of [15N]glycine. At regular intervals, REE was measured by indirect calorimetry (hood system). Based on the arithmetic end-product average of values obtained with urea and ammonia, a significant increase in whole body protein synthesis was observed during the second trimester (5.8 +/- 0.4 g.kg-1.day-1) relative to values obtained both for the NPNL controls (4.5 +/- 0.3 g.kg-1.day-1) and those during the first trimester (4.7 +/- 0.3 g.kg-1.day-1). There was a significant rise in REE during the third trimester both in the preprandial and postprandial states. No correlation was found between REE after meal ingestion and the rate of whole body protein synthesis.

scholarly journals Dietary Carbohydrate Deprivation Increases 24-Hour Nitrogen Excretion without Affecting Postabsorptive Hepatic or Whole Body Protein Metabolism in Healthy Men

2003 ◽  
Vol 88 (8) ◽  
pp. 3801-3805 ◽  
Author(s):  
P. H. Bisschop ◽  
M. G. M. de Sain-van der Velden ◽  
F. Stellaard ◽  
F. Kuipers ◽  
A. J. Meijer ◽  
...  
Keyword(s):  
Total Energy ◽  
Protein Metabolism ◽  
Carbohydrate Content ◽  
Nitrogen Excretion ◽  
Whole Body ◽  
Dietary Carbohydrate ◽  
High Fat ◽  
Body Protein ◽  
Healthy Men ◽  
Low Carbohydrate

Because insulin is an important regulator of protein metabolism, we hypothesized that physiological modulation of insulin secretion, by means of extreme variations in dietary carbohydrate content, affects postabsorptive protein metabolism. Therefore, we studied the effects of three isocaloric diets with identical protein content and low-carbohydrate/high-fat (2% and 83% of total energy, respectively), intermediate-carbohydrate/intermediate-fat (44% and 41% of total energy, respectively), and high-carbohydrate/low-fat (85% and 0% of total energy, respectively) content in six healthy men. Whole body protein metabolism was assessed by 24-h urinary nitrogen excretion, postabsorptive leucine kinetics, and fibrinogen and albumin synthesis by infusion of [1-13C]leucine and [1-13C]valine. The low-carbohydrate/high-fat diet resulted in lower absorptive and postabsorptive plasma insulin concentrations, and higher rates of nitrogen excretion compared with the other two diets: 15.3 ± 0.9 vs. 12.1 ± 1.1 (P = 0.03) and 10.8 ± 0.5 g/24 h (P = 0.005), respectively. Postabsorptive rates of appearance of leucine and of leucine oxidation were not different among the three diets. In addition, dietary carbohydrate content did not affect the synthesis rates of fibrinogen and albumin. In conclusion, eucaloric carbohydrate deprivation increases 24-h nitrogen loss but does not affect postabsorptive protein metabolism at the hepatic and whole body level. By deduction, dietary carbohydrate is required for an optimal regulation of absorptive, rather than postabsorptive, protein metabolism.

Aspects of protein metabolism after elective surgery in patients receiving constant nutritional support

1990 ◽  
Vol 78 (6) ◽  
pp. 621-628 ◽  
Author(s):  
F. Carli ◽  
J. Webster ◽  
V. Ramachandra ◽  
M. Pearson ◽  
M. Read ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Metabolic Rate ◽  
Protein Metabolism ◽  
Protein Turnover ◽  
Resting Metabolic Rate ◽  
Plasma Concentrations ◽  
Whole Body ◽  
Body Protein ◽  
Urinary Nitrogen

1. The present study was designed in an attempt to resolve conflicting views currently in the literature relating to the effect of surgery on various aspects of protein metabolism. 2. Sequential post-operative (2, 4 and 6 days) changes in whole-body protein turnover, forearm arteriovenous difference of plasma amino acids, glucose, lactate and free fatty acids, muscle concentration of free amino acids, RNA and protein, urinary nitrogen and 3-methylhistidine, plasma concentrations of insulin, cortisol and growth hormone, and resting metabolic rate, were measured in six patients undergoing uncomplicated elective total abdominal hysterectomy. 3. All patients received a constant daily diet, either orally or intravenously, based on 0.1 g of nitrogen/kg and an energy content of 1.1 times the resting metabolic rate for 7 days before and 6 days after surgery. 4. Whole-body protein turnover, synthesis and breakdown increased significantly 2 days after surgery (P <0.05) and returned towards pre-operative levels thereafter. 5. Forearm release of branched-chain amino acids and alanine, and efflux of glucose and lactate, were enhanced 4 days after surgery (P <0.05). Muscle glutamine and alanine concentrations were decreased on the fourth and sixth days after surgery (P <0.05). The RNA/protein ratio (indicating the capacity for protein synthesis) was unaltered. 6. A significant increase in urinary nitrogen and 3-methylhistidine was observed on days 3 and 4 after surgery (P <0.05). Thereafter, these parameters remained elevated, although failing to reach statistical significance. 7. The resting metabolic rate was significantly increased (P <0.05) 2 days after surgery but the respiratory quotient (0.77) was unchanged. 8. These data support the contention that whole-body protein synthesis and breakdown increase after surgery. Differences observed pre- and post-operatively between leucine kinetic estimates and other methods of quantifying protein metabolism indicate that only like methodologies should be compared.

scholarly journals Effect of insulin on hind-limb and whole-body leucine and protein metabolism in fed and fasted lambs

1987 ◽  
Vol 58 (3) ◽  
pp. 437-452 ◽  
Author(s):  
V. H. Oddy ◽  
D. B. Lindsay ◽  
P. J. Barker ◽  
A. J. Northrop
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Hind Limb ◽  
Whole Body ◽  
Limb Muscle ◽  
Body Protein ◽  
Leucine Metabolism ◽  
Hind Limb Muscle ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

1. A combination of isotope-dilution and arterio-venous difference techniques was used to determine rates of leucine metabolism and protein synthesis and degradation in a hind-limb preparation (predominantly muscle) and the whole body of eight lambs fed on milk to appetite and eight lambs fasted from 24 to 48 h.2. Compared with fed lambs, fasted lambs showed decreased rates of protein synthesis in both whole body and hind-limb, and in hind-limb muscle, elevated rates of protein degradation.3. The effects of two rates of insulin infusion on whole-body and hind-limb-muscle leucine metabolism, and in turn on protein metabolism, were determined. Insulin had no significant effect on leucine flux or oxidation (and hence protein synthesis and degradation) in whole-body or hind-limb muscle of fed lambs. In fasted lambs insulin progressively reduced arterial leucine concentration and whole-body leucine flux and oxidation, indicating a reduction in both protein synthesis and degradation. Insulin reduced the rate of leucine efflux from hind-limb muscle, which was followed by a reduction in leucine uptake. Insulin increased hind-limb-muscle glucose uptake in both fed and fasted lambs.4. On the basis that hind-limb muscle was representative of skeletal muscle in general, we estimated that muscle accounted for the same percentage (about 27) of whole-body protein synthesis in both fed and fasted lambs. This percentage was unaffected by infusion of insulin, although the absolute rates differed in fed and fasted lambs.

Sign in / Sign up

Export Citation Format

Share Document