SciCombinator

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Concept: Arginine

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The pathophysiology of cardiac syndrome X is multifactorial and endothelial dysfunction has been implicated as important contributing factor. Asymmetric dimethylarginine (ADMA), characterized as a circulating endogenous inhibitor of nitric oxide synthase, may have been implicated as an important contributing factor for the development of endothelial dysfunction. In this study, we aim to assess the predictive power of ADMA for long-term prognosis in patients with cardiac syndrome X.

Concepts: Endothelium, Nitric oxide, Prognosis, Asymmetric dimethylarginine, Arginine, Syndrome X, Cardiac syndrome X

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The scope of this study is the examination of NO(2)+NO(3), 3-nitrotyrosine (3-NT), S-nitrosothiols (RSNO), arginase activity and asymmetric (ADMA) and symmetric (SDMA) dimethyl-l-arginine concentrations in plasma of MS patients during interferon-β1b therapy.

Concepts: Amino acid, Multiple sclerosis, Nitrogen, Endothelium, Nitric oxide, Asymmetric dimethylarginine, Arginine, Nitric acid

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BACKGROUND: Current nutritional approaches have been partially successful in Cystic Fibrosis (CF). Essential amino acids mixtures with high Leucine levels (EAA) have anabolic properties in catabolic conditions, however data in CF are lacking. METHODS: On two days according a randomized crossover design, 15 pediatric CF patients ingested 6.7g EAA versus mixture of total amino acids as present in whey. Whole body protein and Arginine metabolism (as EAA lack Arginine) were assessed by stable isotope methodology. RESULTS: Protein synthesis (P<0.05) but not protein breakdown was higher after EAA and 70% higher values for net anabolism (P<0.001)were found both in patients with and without nutritional failure. Arginine turnover was lower (P<0.001) and de novo Arginine synthesis tended lower (P=0.09) after EAA. Nitric oxide synthesis was not different. CONCLUSIONS: CF patients are highly responsive to EAA intake independent of their nutritional status. Addition of Arginine to the EAA mixture may be warranted in CF.

Concepts: Protein, Amino acid, Metabolism, Nutrition, Essential amino acid, Nitric oxide, Arginine, Catabolism

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In this work a novel biosensor for arginine determination based on the urease inhibition effect has been proposed. Ion-selective field effect transistors were used as transducers. Urease immobilized in glutaraldehyde vapor served as a biorecognition element of the biosensor. Significant part of the work was aimed at proving the urease inhibition by arginine. Optimal concentration of urea for arginine determination was chosen. Detection limit for arginine was 0.05mM. The biosensor selectivity towards different amino acids was studied. The results of quantitative determination of l-arginine in the real sample (a drinkable solution “Arginine Veyron”) were in good agreement with the producer’s data (a relative error was 5.2%). The biosensor showed a good reproducibility of arginine determination.

Concepts: Protein, Amino acid, Acid, Amine, Ammonia, Field-effect transistor, Arginine, Ornithine

25

Many human studies report that nitric oxide (NO) improves sport performance. This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise. L-Citrulline is an amino acid present in the body and is a potent endogenous precursor of L-arginine, which is a substrate for NO synthase. Here, we investigated the effect of oral L-citrulline supplementation on cycling time trial performance in humans.

Concepts: Oxygen, Carbon dioxide, Amino acid, Ammonia, Metabolism, Cellular respiration, Nitric oxide, Arginine

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This study aimed to characterize the role of tropoelastin in eliciting a nitric oxide response in endothelial cells.

Concepts: Blood vessel, Endothelium, Nitric oxide, Vasodilation, Arginine, Nitric oxide synthase, Nitric acid, Endothelium-derived relaxing factor

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An experiment was conducted to evaluate growth performance, apparent ileal digestibility (AID) of amino acids, and plasma concentrations of amino acids, carotenoids, and α1-acid glycoprotein, an acute-phase protein, in broilers inoculated with graded doses of E. acervulina oocysts. Ross 308 male broilers (400 total) were housed in battery cages from 1 to 21 d post-hatch and received common corn-soybean meal-based diets throughout the experiment. At 9 d post-hatch, birds were individually weighed and allotted to 4 treatment groups with 10 replicate cages of 10 birds per cage. At 15 d post-hatch, all birds were inoculated with 1 mL of distilled water that contained 0, 2.5 × 10(5), 5.0 × 10(5), or 1.0 × 10(6) sporulated E. acervulina oocysts. At 21 d, birds were euthanized for collection of blood and ileal digesta. Body weight gain and feed efficiency decreased linearly (P < 0.05) with increasing E. acervulina dose. With the exception of Trp and Gly, AID values decreased (P < 0.05) linearly or quadratically for all amino acids by an average of 2.6 percentage units for birds inoculated with 1.0 × 10(6) oocysts compared with uninfected birds. Infection with E. acervulina caused a quadratic decrease (P < 0.05) in plasma carotenoid concentrations. Plasma concentrations of Arg and Tyr decreased linearly (P < 0.05) with increasing E. acervulina inoculation dose and plasma Gln and Asn decreased quadratically (P < 0.01). Linear increases (P < 0.05) were observed for plasma Lys, Leu, Ile, Val, Pro, and Orn as E. acervulina inoculation dose increased. Plasma α1-acid glycoprotein of broilers was not influenced (P > 0.05) by E. acervulina infection. In conclusion, E. acervulina challenge adversely impacted growth performance, plasma carotenoids, and AID of amino acids in a dose-dependent manner. However, plasma amino acid responses to graded E. acervulina inoculation doses varied considerably among amino acids. Thus, these results indicated that alterations in amino acid metabolism caused by E. acervulina infection extended beyond reduced amino acid digestibility.

Concepts: Protein, Amino acid, Acid, Amine, Ammonia, Metabolism, Essential amino acid, Arginine

23

This work demonstrates the cooperative effect of Q10, vitamin D3, and L-arginine on both cardiac and endothelial cells. The effects of Q10, L-arginine, and vitamin D3 alone or combined on cell viability, nitric oxide, and reactive oxygen species productions in endothelial and cardiac cells were studied. Moreover, the involvement of PI3K/Akt and ERK/MAPK pathways leading to eNOS activation as well as the involvement of vitamin D receptor were also investigated. The same agents were tested in an animal model to verify vasodilation, nitric oxide, and reactive oxygen species production. The data obtained in this work demonstrate for the first time the beneficial and cooperative effect of stimulation with Q10, L-arginine, and vitamin D3. Indeed, in cardiac and endothelial cells, Q10, L-arginine, and vitamin D3 combined were able to induce a nitric oxide production higher than the that induced by the 3 substances alone. The effects on vasodilation induced by cooperative stimulation have been confirmed in an in vivo model as well. The use of a combination of Q10, L-arginine, and vitamin D to counteract increased free radical production could be a potential method to reduce myocardial injury or the effects of aging on the heart.

Concepts: Oxygen, Vitamin D, Mitochondrion, Heart, Endothelium, Nitric oxide, Vasodilation, Arginine

23

Hyperglycemia causes the breakdown of the blood-retinal barrier by impairing endothelial nitric oxide synthase (eNOS) function. Statins have many pleiotropic effects such as improving endothelial barrier permeability and increasing eNOS mRNA stability. The objective of this study was to determine effect of simvastatin on l-arginine transport and NO production under high-glucose conditions in conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB).

Concepts: Cell, Blood vessel, Endothelium, Nitric oxide, Vasodilation, Asymmetric dimethylarginine, Arginine, Nitric oxide synthase

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Purpose Pegylated arginine deiminase (ADI-PEG 20) depletes essential amino acid levels in argininosuccinate synthetase 1 (ASS1) -negative tumors by converting arginine to citrulline and ammonia. The main aim of this study was to determine the recommended dose, safety, and tolerability of ADI-PEG 20, cisplatin, and pemetrexed in patients with ASS1-deficient malignant pleural mesothelioma (MPM) or non-small-cell lung cancer (NSCLC). Patients and Methods Using a 3 + 3 + 3 dose-escalation study, nine chemotherapy-naïve patients (five MPM, four NSCLC) received weekly ADI-PEG 20 doses of 18 mg/m(2), 27 mg/m(2), or 36 mg/m(2), together with pemetrexed 500 mg/m(2) and cisplatin 75 mg/m(2) which were given every three weeks (maximum of six cycles). Patients achieving stable disease or better could continue ADI-PEG 20 monotherapy until disease progression or withdrawal. Adverse events were assessed by Common Terminology Criteria for Adverse Events version 4.03, and pharmacodynamics and immunogenicity were also evaluated. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 for NSCLC and by modified RECIST criteria for MPM. Results No dose-limiting toxicities were reported; nine of 38 reported adverse events (all grade 1 or 2) were related to ADI-PEG 20. Circulating arginine concentrations declined rapidly, and citrulline levels increased; both changes persisted at 18 weeks. Partial responses were observed in seven of nine patients (78%), including three with either sarcomatoid or biphasic MPM. Conclusion Target engagement with depletion of arginine was maintained throughout treatment with no dose-limiting toxicities. In this biomarker-selected group of patients with ASS1-deficient cancers, clinical activity was observed in patients with poor-prognosis tumors. Therefore, we recommend a dose for future studies of weekly ADI-PEG 20 36 mg/m(2) plus three-weekly cisplatin 75 mg/m(2) and pemetrexed 500 mg/m(2).

Concepts: Cancer, Oncology, Amino acid, Lung cancer, Tumor, Neoplasm, Arginine, Mesothelioma