Ratio Of Valine Research Articles

Platelets characteristics in patients with coronary artery disease and atrial fibrillation

The aim. To estimate the connections between platelet morphological characteristics and amino acids (AA) profile in patients with coronary artery disease (CAD) and atrial fibrillation (AF).
 Materials and methods. 300 patients were included in the study. They were divided into 3 groups: first (CAD) – 149 patients with CAD but without arrhythmias, second (CAD+AF) – 124 patients with CAD and AF paroxysm and control group – 27 patients without CAD and arrhythmias. Platelets AA level was detected by method of ion exchange liquid column chromatography. Total platelet count (PC), mean platelet volume (MPV), platelets distribution width (PDW), platelet-to-leukocyte (PLR) were obtained from common blood count.
 Results. Significant decline of PC and rise of MPV and PLR ratio was found in CAD patients and AF paroxysm in comparison with group with CAD without arrhythmia, p < 0.05. Significant increase of isoleucine, leucine and decrease of threonine, serine, glycine, valine levels was found, changes in branched chain amino acids (rise of Isoleucine + Leucine / Valine ratio) and Glycine + Serine (decline Glycine + Serine sum) metabolism were revealed in CAD patients and AF paroxysm in comparison with group with CAD without arrhythmia, p < 0.05. Phenylalanine / Tyrosine ratio was significantly elevated in CAD patients with and without AF, p < 0.05.
 Taurine, serine, and glycine correlated with platelets morphological characteristics: PC (r = 0.714, r = 0.732 and r = 0.340 consequently), MPV (r = -0.724, r = -0.390 and r = -0.571 consequently), PDW (r = -0.666 and r = -0.364 consequently) and PLR (r = 0.586 and r = 0.648 consequently), p < 0.05. Platelets glycine (AUC = 0.8760), valine (AUC = 0.8707), leucine (AUC = 0.8267) and threonine (AUC = 0.8213) levels are closely connected with AF paroxysm in CAD patients by ROC-analysis results, p < 0.05.
 Platelets amino acids combinations: Glycine + 0.6 × Valine (AUC = 0.9987), Threonine – 3.6 × Leucine (AUC = 0.9040) were found in prediction AF paroxysm for CAD patients by ROC-analysis results, p < 0.05.
 Conclusions. Connections between platelets morphology and AA profile violations in patients with CAD and AF paroxysm were found in our study.

265 Interactive Effects of Dietary Isoleucine and Valine Ratios to Lysine in Response to Varying Leucine to Lysine Ratios on Pectoralis Major Muscle Protein Expression in Commercial Broilers

Abstract Optimizing the dietary concentrations and ratios of branched-chain amino acids (BCAA) is necessary to optimize broiler chicken growth performance and carcass meat yield. A central composite design (CCD) study was conducted to understand the impact of dietary BCAA concentrations and ratios on Pectoralis major (PM) muscle protein expression involved in mTOR and related protein synthesis pathways as well as and investigate the mechanisms behind how BCAA ratios affect broiler growth and muscle protein accretion. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens (n = 18 birds per pen). Before the initiation of the experimental finisher phase, all pens were standardized to contain 15 birds per pen. Each pen received 1 of 15 dietary treatments in the 23 CCD with 6 center points from 20 to 35 d of age, varying in digestible ratios of valine:lysine (Val:Lys; 64 to 87), leucine:lysine (Leu:Lys; 110 to 185), and isoleucine:lysine (Ile:Lys; 52 to 75). On d 35, 1 bird per pen was randomly selected for PM protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Ribosomal protein S6 kinase (RPS6KA3), eukaryotic elongation factor 2 (EEF2), eukaryotic translation initiation factor 4B (EIF4B), eukaryotic translation initiation factor 4E (EIF4E), CAP-Glycine domain containing linker protein 1 (CLIP1), mitogen-activated protein kinase 3 (MAPK3), Protein kinase domain-containing protein (MAP2K1), Dual-specificity mitogen-activated protein kinase kinase 2 (MAP2K2), paxillin (PXN), and regulator complex protein (LAMTOR3) were identified, quantified, and analyzed as a CCD using the RSREG procedure of SAS ver. 9.4 with significance set at P ≤ 0.10. The surface response models for RPS6KA3, EEF2, EIF4B, EIF4E, MAPK3, MAP2K1, MAP2K2, CLIP1, PXN, and LAMTOR3 were not significant (P ≥ 0.926; R2 values ≤ 0.1). No linear (P ≥ 0.5223), quadratic (P ≥ 0.0.634) or cross product (P ≥ 0.6238) regression effects were observed for any of the proteins analyzed. A minimum stationary point was observed for RPS6KA3, EEF2, MAPK3, and LAMTOR3. However, optimal values for the other proteins could not be obtained due to stationary saddle points. Overall, the results in this study indicate that varying concentrations of dietary BCAA may not impact expression of proteins related to broiler skeletal muscle growth on d 35 following the 15-d treatment period, despite the influence on live performance. This is a limitation of this study and suggests that if the mTOR pathway was involved it was not still differentially up- or down-regulated at this time point. Further investigation and new studies with multiple time points will be required to better understand the mechanisms behind how BCAA impact broiler growth and muscle development.

Dietary Valine/Isoleucine Ratio Impact Carcass Characteristics, Meat Edible Quality and Nutritional Values in Finishing Crossbred Duroc × Landrace × Yorkshire Pigs With Different Slaughter Weights.

The aim of this study was to investigate effects of dietary ratio of valine to isoleucine [R(V/I)] on carcass characteristics and meat quality of finishing pigs and whether slaughter weight influence the effect. We carried out a 2 × 3 factorial trial with two slaughter weight (105 vs. 130 kg) and three R(V/I) (0.58, 1.23, and 2.60 at 75–100 kg body weight, and 0.70, 1.24, and 2.39 at 100–135 kg body weight for L-, N- and H-R (V/I), respectively). Data show that increasing slaughter weight significantly increased meat color (a*45 min and b*45 min), drip loss and shear force (P < 0.05). Meanwhile, increasing slaughter weight reduced sarcomere length, the proportion of protein-bound water, and most kinds of muscular total amino acid contents except for tryptophan and arginine, while increased contents of muscular free lysine, tryptophan, leucine, isoleucine, valine, alanine, and arginine in the M. longissimus thoracis (P < 0.05). Health lipid indices based on fatty acid composition of intramuscular lipid were improved as the slaughter weight increased (P < 0.05). Notably, pigs received N-R (V/I) diet improved carcass traits in terms of thinner backfat thickness and higher fat-free lean index, as well as increased meat flavor-contributing amino acids at the cost of reduced intramuscular fat content and increased shear force of cooked meat compared with the pigs fed L-R (V/I) and H-R(V/I) diets (P < 0.05). H-R (V/I) diet decreased ultimate pH value and sarcomere length of the skeletal muscle but increased the proportion of free water (T23), consequently, increased drip loss and cooking loss of fresh meat in pigs (P < 0.05). In conclusion, both slaughter weight and dietary ratio of valine to isoleucine exerted significant impacts on carcass characteristics, meat quality and nutrition values. In particular, carcass traits and meat color of lighter pigs were more susceptible to the influence of dietary R (V/I) relative to heavier pigs.

Comparative Analysis of the Mitochondrial Genome of Galatheanthemum sp. MT-2020 (Actiniaria Galatheanthemidae) From a Depth of 9,462 m at the Mariana Trench

The hadal zone, which represents the deepest marine habitat on Earth (6,000–11,000 m), is a harsh environment mainly characterized by extremely high hydrostatic pressure, and this habitat is believed to have a high degree of endemism. The deep-sea anemone family Galatheanthemidae comprises two valid species exclusively from the hadal; however, no other information about this family is currently available. In the present study, a sea anemone was collected from a depth of 9,462 m at the Mariana Trench and was defined as Galatheanthemum sp. MT-2020 (Actiniaria Galatheanthemidae). The mitochondrial genome of Galatheanthemum sp. MT-2020 was circular, was 16,633 bp in length, and contained two ribosomal RNA genes, 13 protein-coding genes and two transfer RNA genes. The order of the genes of Galatheanthemum sp. MT-2020 was identical to that of the majority of the species of the order Actiniaria. The value of the AT-skew was the lowest in the whole mitochondrial genome, with a positive GC skew value for the atp8 gene, while other species, except Antholoba achates, had the negative values of the GC skew. Galatheanthemum sp. MT-2020 was clustered with another abyssal species, Paraphelliactis xishaensis, in the phylogenetic tree, and these species diverged in the early Jurassic approximately 200 Mya from the shallow-sea species. The usage ratio of valine, which is one of the five amino acids with the strongest barophilic properties, in the mitochondrial genomes of the two abyssal species was significantly higher than that in other species with habitats above the depth of 3,000 m. The ω (dN/dS) ratio of the genomes was 2.45-fold higher than that of the shallow-sea species, indicating a slower evolutionary rate. Overall, the present study is the first to provide a complete mitogenome of sea anemones from the hadal and reveal some characteristics that may be associated with adaptation to an extreme environment.

The nuclear magnetic resonance metabolic profile: Impact of fasting status

IntroductionMeasurement of lipoprotein subclass concentration (-c), particle number (-p), and size (-s) by nuclear magnetic resonance (NMR) has gained traction in the clinical laboratory due to associations between smaller lipid particle sizes and atherogenic risk, especially for LDL-p. The standard protocols for lipoprotein measurements by NMR require fasting blood samples; however, patients may not fast properly before sample collection. The study objective was to evaluate the impact of fasting status on the NMR-based lipid profile and to identify key parameters differentiating between fasting and post-meal specimens. MethodsForty-eight self-reported healthy male and female participants were recruited. Blood was collected after a 12 h fast and 4 h after a high fat meal. Samples were analyzed using the AXINON LipoFIT by NMR assay. The measurements included triglyceride, total cholesterol, IDL-c, and LDL, HDL, VLDL concentration, particle number, and size, as well as glucose, and four amino acids (alanine, valine, leucine and isoleucine). ResultsAs expected, triglycerides increased after the meal (58%, p < 0.0001). Significant changes were also observed for VLDL, LDL, and HDL parameters, and the branched chain amino acids. The ratio of Valine*VLDL-c/LDL-c or Isoleucine*VLDL-c/LDL-c provided equally effective differentiation of fasting and post-meal samples. The ratio cutoffs (79.1 and 23.6 when calculated using valine and isoleucine, respectively) had sensitivities of 86% and specificities of 93–95%. ConclusionsThe clinical impact on NMR results from post-meal samples warrants further evaluation. Algorithms to differentiate fasting and post-meal specimens may be useful in identifying suboptimal specimens.

Manufacturing Process, In Vivo and In Vitro Digestibility Assessment of an Enteral Feeding Product Hydrolyzed from Locally Available Ingredients Using Commercial Enzymes

A ready-for-use enteral feeding product was manufactured based on energy standard mixing using hydrolyzed products from local foods (i.e., loin pork, carrot, pumpkin, soybean, rice, and potato). When compared to enteral foods based on defined ingredients, the manufactured product is more cost-effective, appropriately functional and has similar physicochemical properties. Relative protein digestibility for in vitro value was tested by using enzyme pepsin, pH-drop and pH-stat method with three different enzymes. The product was shown to be easily digested with an in vivo digestibility value of 89.7%. Molecule sizes of components in the product ranged from 3.5 to 8.5 kDa, determined by SDS-PAGE, and the average molecular weight was 1.52 kDa, determined by Gel Permeation Chromatography (GPC) method. In terms of nutritional value, the product achieved a caloric density of 1 kcal/mL, dietary fibers of 1.48 g per 100 mL and provided both oligomeric and monomeric forms of protein. In addition, the product has the leucine: isoleucine: valine ratio of 2:1:1, thus facilitating the absorption of the protein. In conclusion, the manufactured enteral feeding product has been shown to be appropriate for providing nutritional support for patients.

Alteration of muscle fiber characteristics and the AMPK-SIRT1-PGC-1α axis in skeletal muscle of growing pigs fed low-protein diets with varying branched-chain amino acid ratios.

There mainly exists four major myosin heavy chains (MyHC) (i.e., I, IIa, IIx, and IIb) in growing pigs. The current study aimed to explore the effects of low-protein diets supplemented with varying branched-chain amino acids (BCAAs) on muscle fiber characteristics and the AMPK-SIRT1-PGC-1α axis in skeletal muscles. Forty growing pigs (9.85 ± 0.35 kg) were allotted to 5 groups and fed with diets supplemented with varying leucine: isoleucine: valine ratios: 1:0.51:0.63 (20% crude protein, CP), 1:1:1 (17% CP), 1:0.75:0.75 (17% CP), 1:0.51:0.63 (17% CP), and 1:0.25:0.25 (17% CP), respectively. The skeletal muscles of different muscle fiber composition, that is, longissimus dorsi muscle (LM, a fast-twitch glycolytic muscle), biceps femoris muscle (BM, a mixed slow- and fast-twitch oxido-glycolytic muscle), and psoas major muscle (PM, a slow-twitch oxidative muscle) were collected and analyzed. Results showed that relative to the control group (1:0.51:0.63, 20% CP), the low-protein diets with the leucine: isoleucine: valine ratio ranging from 1:0.75:0.75 to 1:0.25:0.25 especially augmented the mRNA and protein abundance of MyHC I fibers in BM and lowered the mRNA abundance of MyHC IIb particularly in LM (P < 0.05), with a concurrent increase in the activation of AMPK and the mRNA abundance of SIRT and PGC-1α in BM (P < 0.05). The results reveal that low-protein diets supplemented with optimal BCAA ratio, i.e. 1:0.75:0.75-1:0.25:0.25, induce muscle more oxidative especially in oxido-glycolytic skeletal muscle of growing pigs. These effects are likely associated with the activation of the AMPK-SIRT1-PGC-1α axis.

Effect of dietary supplementation with amino acids on boar sperm quality and fertility

The aim of this study was to evaluate the effects of dietary supplementation with amino acids on sperm quality and fertility rates after insemination with boar semen. Twelve Yorkshire boars were paired by age and allocated to one of two dietary treatments composed of total lysine levels of 0.64% (T1) and 0.96% (T2), with the lysine: methionine: threonine: tryptophan: valine ratio in the diets set to 100:27:73:19:69 through the addition of synthetic amino acids. Semen was collected twice weekly (phase 1, 1–12 wk); every other day (phase 2, 13–16 wk); twice weekly (phase 3, 17–26 wk); and daily (phase 4, 27–28 wk). Semen was collected from boars during phase 3 and used to inseminate 64 multiparous sows. Our results showed that sperm concentration and total sperm cells were greater in boars in T2 than in boars in T1 in phases 2 and 4 (P<0.05). Sperm motility parameters, morphologically normal sperm, and acrosome integrity in T2 boars were greater than those in T1 boars (P<0.05) during the experiment. Free amino acid concentrations in seminal plasma increased in T2 boars (P<0.05). Furthermore, sows inseminated with semen collected from T2 boars gave birth to more live piglets than those inseminated with semen collected from T1 boars (P=0.04). In conclusion, supplementation of boar diet with amino acids improves sperm quality, and subsequently increases fertilization capacity and the number of live piglets.

Solid Phases in the System l-Valine—l-Isoleucine

Two model compounds—valine C5H11NO2 (l-Val) and isoleucine C6H13NO2 (l-Ile)—were chosen to study isomorphism of the compounds formed by enantiomeric molecules having similar shapes, but differing in the number of chiral centers. The X-ray powder diffraction method was applied to investigate samples with various ratios of valine and isoleucine crystallized from aqueous solutions by cooling and isothermal methods. Limited solid state miscibility between valine and isoleucine was established. A non-equimolar discrete compound with the molecular ratio Val:Ile = 2:1 (V2I) has been discovered, and its crystal structure was determined. Accordingly, the corresponding regions of solid solutions and two-phase areas in-between were distinguished. Solubility data in water support the phase behavior in the system.

The Role of Metabolomics in Osteoarthritis Research

Metabolomics is the comprehensive analysis of small molecules in a biological system and has generated great interest for identifying novel biomarkers for disease diagnosis and pharmaceutical treatment. Metabolomics has been used to identify citrate and choline as biomarkers for prostate and breast cancer, respectively. In fact, both tests are now clinically available and supported by most health insurance providers.1, 2 Metabolites are the end-products of cellular processes, and their levels can be regarded as the ultimate response of biological systems to genotype, phenotype, and environmental conditions. They encompass a diverse group of low-molecular weight compounds including lipids, amino acids, peptides, nucleic acids, organic acids, vitamins, thiols, and carbohydrates,3 and are commonly analyzed using nuclear magnetic resonance spectroscopy, liquid chromatography/mass spectrometry, and/or gas chromatography/mass spectrometry. Metabolomics may be well suited for osteoarthritis (OA) research for many reasons including the tremendous heterogeneity in the disease process and recognition that no single biomarker can reflect the breadth of temporal and pathological processes associated with OA.4 Combining several biomarkers into a panel will assuredly increase the discriminatory capability5, as would occur with metabolic profiling. Secondly, since metabolic perturbations are real-time, they indicate the current disease state, a distinct advantage over current clinical diagnostics and disease monitoring techniques for OA, such as radiography. Metabolomics has been employed to detect metabolic perturbations in urine, blood, synovium, and synovial fluid (SF) of animal models and patients with OA. Lamers and co-workers6 used nuclear magnetic resonance to study the urine from guinea pigs that spontaneously develop OA. Disturbances in lactic acid, malic acid, hypoxanthine and alanine were found to contribute heavily to the metabolic profile of OA. These investigators further studied the urine of humans with and without OA and found distinct patterns in the NMR spectra that could discriminate between groups.4 Zhai and co-workers7 employed metabolomics on human serum in a study of patients with and without knee OA. The investigators demonstrated that the ratios of valine and leucine to histidine were predictive of OA, pointing towards interest in the use of branched-chain amino acids (BCAA) as potential biomarkers.7 Many of these studies of venous plasma or urine identify metabolites that may be related to aging, altered muscle mass, and other factors that may confound the unique signature of a pathological OA joint. For these reasons, SF may yield the most accurate, real-time, and joint-specific metabolic profile. Metabolomics has been performed on SF from experimentally induced OA in canine knee joints.8 The nuclear magnetic resonance spectra demonstrated increased concentrations of lactate, pyruvate, glycerol, alanine, isoleucine, hydroxybutyrate, hydroxyisobutyrate, and lipoprotein associated fatty acids. The investigators concluded that the intra-articular environment of OA was more hypoxic and acidotic than in the normal joint, and that arthritic joints may rely in part upon altered lipid metabolic pathways. We have performed metabolomics on both human synovium and SF. In our first study, the metabolic profile of conditioned media collected from synovium explant cultures was obtained for tissues from patients undergoing total knee arthroplasty (end-stage OA) and from patients undergoing ligament or meniscal repair with little or no evidence of OA.9 Thirteen metabolites were significantly elevated in the end-stage OA group and included glutamine, succinate, pro-hydroxyproline, amongst others. Despite results suggestive of a distinct metabolic profile in OA, the synovium culture method does not easily translate into clinical practice. In a second study, we performed metabolomics on ankle SF of patients with and without ankle OA.10 Results identified 106 metabolites as significantly elevated in the OA samples and represented perturbations in virtually all metabolic pathways, including amino acid metabolism, carbohydrate metabolism, mitochondrial oxidation, lipid metabolism, peptide, vitamin, nucleotide synthesis, and redox homeostasis. More importantly, when a rigorous decision tree analysis was applied to the metabolic profiles of the two populations, a 90% discriminatory accuracy was achieved, indicating the potential use of this technology as a diagnostic tool for OA. Studies are ongoing to confirm these findings in a larger population and to generate a narrowed panel of metabolic biomarkers and measurement methods for translation into the clinic. In conclusion, metabolic profiling of biofluids and tissues can provide a panoramic view of the current physiologic state of a biological system such as the intra-articular environment of an osteoarthritic joint. We envision the role of metabolomics for OA as a clinically applied diagnostic tool in which a sample of a patient’s synovial fluid would be analyzed for a panel of metabolite biomarkers, similar to following serial values from a complete blood count. Alterations in the metabolic profile could indicate disease progression or a therapeutic response at a resolution not possible with currently employed clinical techniques.

Serum branched-chain amino acid to histidine ratio: a novel metabolomic biomarker of knee osteoarthritis

ObjectiveThere is a pressing need to develop reliable molecular biomarkers in osteoarthritis. The aim of the study was to identify novel serum biomarkers for osteoarthritis using a metabolomics approach.MethodsA two-stage...

001 NOVEL BIOMARKERS OF KNEE OSTEOARTHRITIS IDENTIFIED USING METABOLIC PROFILING

Purpose: There is a pressing need to develop reliable molecular biomarkers that can inform on the process of joint destruction in osteoarthritis (OA). Such biomarkers could aid in drug development by identifying fast progressors and early response to therapy. Recent advance in metabolomics (the quantitative analysis of all metabolites present within a biological sample) has opened new avenues for biomarker identification. The aim of the study, therefore, was to identify serum metabolic biomarkers for OA using a metabolomics approach. Methods: 123 knee OA cases and 299 controls were selected from the TwinsUK cohort. Knee OA was defined as either radiographic, self-reported OA, or total knee joint replacement due to primary OA. All the subjects were unrelated Caucasian females. Their frozen serum samples were retrieved and assessed for targeted metabolite profiling using API4000 Q TRAP LC/MS/MS System (Applied Biosystems, Darmstadt, Germany) equipped with Schimadzu Prominence LC20AD pump and SIL-20AC auto sampler with AbsoluteIDQTM Kit (Biocrates life sciences AG, Austria). Results: A total of 163 serum metabolites were assessed and their concentrations were obtained. The mean of the coefficient of variation (CV) for the 163 metabolites was 0.07±0.05 and 90% of the metabolites had a CV of less than 0.10. The ratios of all pair metabolite concentrations were calculated and tested for the association with knee OA. Overall 14 ratios were significantly associated with knee OA with p ≤ 1.9×10-6 which was the significance level after conservative Bonferroni correction. These ratios were mainly involved in valine and acylcarnitine, namely the ratios of valine to arginine, glutamine, glycine, histidine, tyrosine, and dodecanedioyl-L-carnitine, and the ratios of fumaryl-L-carnitine to propenoyl-L-carnitine, dodecanedioyl-L-carnitine, and lysophosphatidylcholine acyl C26:1. The association between these ratios and knee OA remained strong even after adjustment for age and BMI. Conclusions: This is the first study reporting the identification of novel OA biomarkers using a metabonomics approach. The results suggest that amino acid and acylcarnitine metabolic pathways involving valine and fumaryl-L-carnitine are implicated in the development of OA and have potential clinical use as biomarkers.

Optimization of a Valine:Isoleucine Methyl Ester Pheromone Blend and Comparison of Robbins and Trécé Traps for Capture of Phyllophaga anxia (Coleoptera: Scarabaeidae) in Rhode Island

Eight ratios of L-valine:L-isoleucine methyl esters were tested in Robbins traps for capture of Phyllophaga anxia (LeConte) adult males. The 90:10, 80:20, and 60:40 ratios of valine:isoleucine were the most effective blends for capture of beetles in Rhode Island. Females were captured in small numbers in some traps but not consistently to any particular blend. Other male Phyllophaga species captured included Phyllophaga fusca (Frölich), Phyllophaga forsteri (Burmeister), P. hirsuta (Knoch), and P. marginalis (LeConte). The number of these species collected was low, and it was not possible to determine whether they were attracted to any particular pheromone blend. Peak captures of P. anxia males occurred 31 May in 1999 and 2002 in Kingston, RI. The standard Japanese beetle trap manufactured by Trécé (Adair, OK) captured significantly more beetles than the Robbins trap. Because the Trécé trap is already marketed for Japanese beetles, a lure and trapping system can be adopted for P. anxia.

Changes in amino acid enantiomers and microbial performance in soils from a subtropical mountain oasis in Oman abandoned for different periods

An important feature of maintaining the agricultural stability in millennia-old mountain oases of northern Oman is the temporary abandonment of terraces. To analyse the effects of a fallow period on soil microbial performance, i.e. microbial activity and microbial biomass, samples of eight terrace soils abandoned for different periods were collected in situ, assigned to four fallow age classes and incubated for 30 days in the laboratory after rewetting. The younger fallow age classes of 1 and 5 years were based on the records of the farmers’ recollections, the two older fallow age classes of 10–20 and 25–60 years according to the increase in the d -to- l ratio of valine and leucine enantiomers. The increase in these two ratios was in agreement with that of the d -to- l ratio of lysine. The strongest relationship was observed between the increase in the d -to- l ratio of lysine and the decrease in soil microbial biomass C. However, the most stringent coherence between the increase in fallow age and soil properties was revealed by the decreases in cumulative respiration and net N mineralisation rates with decreasing availability of substrate to soil microorganisms. During the 30-day incubation following rewetting, relative changes in microbial activity (respiration and net N mineralisation) and microbial biomass (C and N) indices were similar in the eight terrace soils on a fallow age-class-specific level, indicating that the same basic processes occurred in all of the sandy terrace soils investigated.

The optimal ratio of apparent digestible valine to lysine to maximize growth performance of the nursery pig (2001)

A total of 210 nursery pigs (initially 19.6 lb and approximately 28 d of age) were used in a 21-d growth assay to determine the optimal ratio of valine to lysine to maximize growth performance. The seven treatments consisted of a basal diet (14.2% CP; 1.07% apparent digestible lysine) with increasing ratios of valine:lysine (48, 53, 58, 63, 69, and 74%) and a negative control containing 0.97% lysine and 0.79% apparent digestible valine. Results indicate that the optimal apparent digestible valine:lysine ratio for the nursery pig is 58 and 64% for ADG and F/G, respectively. Therefore, most typical nursery diets will contain adequate amounts of valine to maximize growth performance of nursery pigs.; Swine Day, Manhattan, KS, November 15, 2001

Determination of low isotopic enrichment of L-[1-13C]valine by gas chromatography/combustion/isotope ratio mass spectrometry: a robust method for measuring protein fractional synthetic rates in vivo.

A method was developed for measuring protein fractional synthetic rates using the N-methoxycarbonylmethyl ester (MCM) derivative of L-[1-13C]valine and on-line gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The derivatization procedure can be performed rapidly and GC separation of valine from the other branched-chain amino acids, leucine and isoleucine, is easily obtained. A good linear relationship was observed between the increment of the 13C/12C isotope ratio in CO2 gas derived from the combustion of derivatized valine and the tracer mole ratio of L-[1-13C]valine to unlabelled valine. The limit of quantitation was at an L-[1-13C]valine tracer mole ratio of 0.0002. The method was used to measure the isotopic enrichment of L-[1-13C]valine in standard mixtures and in skeletal muscle of six growing piglets infused with L-[1-13C]valine (2 mg kg-1 h-1 for 6 h). After infusion of L-[1-13C]valine the mean tracer mole ratio in plasma of L-[1-13C]valine at the isotopic steady state was 0.0740 +/- 0.0056 (GC/MS, mean +/- SEM) and the mean tracer mole ratio of valine in muscle protein fraction at 6 h was 0.000236 +/- 0.000038 (GC/C/IRMS). The resulting mean protein fractional synthetic rate in piglet skeletal muscle was 0.052 +/- 0.007% h-1, which is in good agreement with literature data obtained with alternative, more elaborate techniques. By this method protein fractional synthetic rates can be measured at low isotopic enrichment levels using L-[1-13C]valine, the MCM derivative and on-line GC/C/IRMS.

A prospective randomized study of glutamine-enriched parenteral compared with enteral feeding in postoperative patients

Plasma amino acids were measured in 17 postoperative subjects randomly assigned to receive for > or = 5 d tube feeding or total parenteral nutrition (TPN) that had identical energy, nitrogen, and glutamine contents. Subjects required gastric or pancreatic surgery for malignancy and were well-matched for age and body mass index. Tube feeding or TPN began on postoperative day 1 and advanced in daily 25% increments to meet goals of 105 kJ . kg body wt-1 . d-1, 1.5 g protein . kg body wt-1 . d-1, and 0.3 g glutamine . kg body wt-1 . d-1. Delivered energy, nitrogen, and glutamine were closely matched on day 4. Nitrogen balance and plasma proteins did not differ significantly between feeding groups. Total indispensable amino acids, branched-chain amino acids, and glutamine declined 25% on postoperative day 1 compared with preoperative day 0. Indispensable and branched-chain amino acid concentrations were restored with 5 d of either tube feeding or TPN. Glutamine concentrations did not differ significantly by feeding group, though a trend suggested that glutamine recovered more slowly in the tube-fed than in the TPN-fed subjects. Plasma amino acids otherwise reflected formula composition with ratios of valine to leucine of 1.24 and 3.69 mumol/L in subjects receiving 5 d of tube feeding or TPN, respectively. These findings suggest that glutamine-enriched tube feeding and TPN can result in similar profiles for most plasma amino acids at carefully matched doses.

Mesocaval and distal splenorenal shunts: effect on hepatic function, hepatic hemodynamics, and portal systemic encephalopathy.

The effect of the mesocaval interposition shunt (n = 12) and the distal splenorenal shunt (n = 9) on the wedged hepatic venous pressure, the estimated hepatic blood flow, quantitative hepatic function, and the rate of portal systemic encephalopathy was evaluated in 21 patients who had bled from esophageal varices. After mesocaval shunt the wedged hepatic venous pressure was significantly reduced by 42% (from 26 +/- 3 mm Hg to 15 +/- 5 mm Hg, P less than 0.001) compared to 16% only (from 25 +/- 3 mm Hg to 21 +/- 2 mm Hg, P less than 0.005) after distal splenorenal shunt. The estimated hepatic blood flow also decreased significantly after mesocaval shunt by 61% (from 1.45 +/- 0.46 l/min to 0.56 +/- 0.25 l/min, P less than 0.001) compared to 29% (from 1.29 +/- 0.32 l/min to 0.91 +/- 0.39 l/min, P less than 0.05) after distal splenorenal shunt. Despite significantly different influences of both types of shunt operations on wedged hepatic venous pressure and estimated hepatic blood flow (P less than 0.001), postoperative changes of hepatic function were comparable in both groups of patients. The galactose elimination capacity, the initial plasma disappearance rate of Bromsulphalein, and the plasma ratio of valine, leucine, and isoleucine to phenylalanine and tyrosine were reduced by 13%, 26%, and 29%, respectively, after mesocaval shunt, compared to 12%, 25%, and 17% after distal splenorenal shunt. Only two patients of the mesocaval shunt group with the largest decrease in estimated hepatic blood flow developed portal systemic encephalopathy postoperatively, and the distal splenorenal shunt patients with their minor hemodynamic sequelae remained free of portal systemic encephalopathy.

Infusion of branched chain amino acids after partial hepatectomy in man.

A branched chain amino acid (BCAA) solution was infused for 2 weeks following major hepatic resection in patients with malignant tumors of the liver. The infusion caused a significant reduction in plasma concentrations of phenylalanine, tyrosine, methionine, and ammonia as compared with the control patients. The BCAA infusion also prevented a marked fall in the molar ratio of valine, leucine, and isoleucine to phenylalanine and tyrosine. No untoward effects of the treatment were found. Although further studies are necessary to determine an ideal dose of BCAAs from the viewpoint of nitrogen balance, the BCAA solution seems to be a useful nutritional element after major hepatic resection if given with hypertonic glucose.

The Effect of Valine Deficiency on Neutral Amino Acid Patterns in Plasma and Brain of the Rat

Valine deficiency in rats produces motor incoordination attributable to selective damage to the red nuclei, midbrain structures that modulate motor activity. Neither incoordination nor red nuclei damage occurs in rats deprived of valine, isoleucine and leucine, thus suggesting that valine neurotoxicity results from amino acid imbalance rather than from lack of valine per se. To explore this possibility, we compared neutral amino acid patterns in plasma and brain of rats fed for 7 days a complete diet fed ad libitum or pair-fed, a valine-free diet or a diet lacking in all three essential branched-chain amino acids (BCAA). Statistical evaluation showed that plasma valine in valine-deprived rats was lower (P < 0.01) than in pair-fed and ad libitum-fed controls but did not differ from rats lacking BCAA. Brain valine in valine-deprived rats did not differ from ad libitum-fed controls and actually was higher (P < 0.01) than in pair-fed and BCAA-deprived rats. The most striking changes seen in the amino acid pattern of valine-deprived rats as compared to all other groups were in the increased leucine:valine ratio (P < 0.01 for plasma and brain) and in the increased leucine + isoleucine:valine ratio (P < 0.01, plasma; P < 0.001, brain). These results are consistent with the view that amino acid imbalance is a critical factor in the development of the neurotoxicity of valine deficiency.