S-nitrosothiols affect fibrinogen structure and function.

S-Nitrosoglutathione, (50 muM) inhibited the initial rate of thrombin-catalyzed fibrinogen polymerization by ∼80%. The fact that the same concentration of S-nitrosoglutathione had no effect on thrombin-dependent hydrolysis of tosylglycylprolylarginine-4-nitranilide acetate suggested that the nitrosothiol was affecting fibrinogen structure. This was confirmed by circular dichroism spectroscopy where S-nitrosoglutathione and S-nitrosohomocysteine increased the alpha-helical content of fibrinogen by ∼19% and 11% respectively. S-carboxymethylamido derivatives of glutathione or Hcys had no effect on the fibrinogen 2° structure. The S-nitrosothiol-dependent 2° structural effects were reversed upon gel filtration chromatography suggesting that the effects were allosteric. Further evidence for fibrinogen-S-nitrosoglutathione interactions were obtained from S-nitrosoglutathione-dependent quenching of the intrinsic fibrinogen Trp fluorescence as well as the quenching of the S-NO circular dichroic absorbance of S-nitrosoglutathione as a function of fibrinogen concentration. These studies enabled the estimation of a K D of ∼40 muM for the fibrinogen-S-nitrosoglutathione interaction with a stoichiometry of 2:1 (S-nitrosoglutathione:fibrinogen).Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2001 .V54. Source: Masters Abstracts International, Volume: 40-03, page: 0707. Adviser: B. Mutus. Thesis (M.Sc.)--University of Windsor (Canada), 2001

Effects of short-term hyperoxia on erythropoietin levels and microcirculation in critically Ill patients: a prospective observational pilot study

BACKGROUND: The normobaric oxygen paradox states that a short exposure to normobaric hyperoxia followed by rapid return to normoxia creates a condition of 'relative hypoxia' which stimulates erythropoietin (EPO) production. Alterations in glutathione and reactive oxygen species (ROS) may be involved in this process. We tested the effects of short-term hyperoxia on EPO levels and the microcirculation in critically ill patients.METHODS: In this prospective, observational study, 20 hemodynamically stable, mechanically ventilated patients with inspired oxygen concentration (FiO2) \ue2\u89\ua40.5 and PaO2/FiO2\ue2\u80\u89\ue2\u89\ua5\ue2\u80\u89200\uc2\ua0mmHg underwent a 2-hour exposure to hyperoxia (FiO2 1.0). A further 20 patients acted as controls. Serum EPO was measured at baseline, 24\uc2\ua0h and 48\uc2\ua0h. Serum glutathione (antioxidant) and ROS levels were assessed at baseline (t0), after 2\uc2\ua0h of hyperoxia (t1) and 2\uc2\ua0h after returning to their baseline FiO2 (t2). The microvascular response to hyperoxia was assessed using sublingual sidestream dark field videomicroscopy and thenar near-infrared spectroscopy with a vascular occlusion test.RESULTS: EPO increased within 48\uc2\ua0h in patients exposed to hyperoxia from 16.1 [7.4-20.2] to 22.9 [14.1-37.2] IU/L (p\ue2\u80\u89=\ue2\u80\u890.022). Serum ROS transiently increased at t1, and glutathione increased at t2. Early reductions in microvascular density and perfusion were seen during hyperoxia (perfused small vessel density: 85% [95% confidence interval 79-90] of baseline). The response after 2\uc2\ua0h of hyperoxia exposure was heterogeneous. Microvascular perfusion/density normalized upon returning to baseline FiO2.CONCLUSIONS: A two-hour exposure to hyperoxia in critically ill patients was associated with a slight increase in EPO levels within 48\uc2\ua0h. Adequately controlled studies are needed to confirm the effect of short-term hyperoxia on erythropoiesis.TRIAL REGISTRATION: ClinicalTrials.gov ( www.clinicaltrials.gov ), NCT02481843 , registered 15th June 2015, retrospectively registered

Effetti dell'olio supplementato con vitamine D3, K1, B6 in diverse categorie di soggetti

Numerosi sono gli studi che indicano un effetto benefico delle vitamine D3, K1, B6 nel metabolismo osseo e nello stress ossidativo. Pertanto lo scopo della presente tesi è stato quello di valutare gli effetti di un olio contenente vitamine D3, K1, B6 (VitVOO) rispetto ad un olio usato come placebo (PlaVOO) in donne in età fertile, in menopausa e i bambini con scarso accrescimento corporeo. In donne in età fertile è emerso che l’ucOC, risultava diminuita dopo assunzione del VitVOO rispetto al PlaVOO, come pure l’UCR. Infatti, è stata osservata una diminuzione della produzione di radicali liberi, maggiore rispetto a quella osservata solo con PlaVOO (diminuzione dei TBARs, degli idroperossidi lipidici e i dieni coniugati); è stata inoltre dimostrata una fluidificazione delle membrane piastriniche. In donne in menopausa, dopo 1 anno di supplementazione orale con VitVOO, l’ucOC risultava diminuita come pure l’UCR. Questi dati sono stati confermati dalla indagine della MOC effettuata sulle pazienti, con diminuzione del valore di T score a valori meno negativi. Inoltre è emerso che tutti i marker di stress ossidativi (TBARs, idroperossidi lipidici e i dieni coniugati) mostravano una riduzione significativa dopo l'integrazione con VitVOO, mentre la capacità totale antiossidante risultava aumentata. Nei bambini con diagnosi di inappetenza e con scarso accrescimento corporeo si è valutato un marker biochimico specifico del riassorbimento osseo umano, che è l’escrezione urinaria di NTx. I risultati hanno mostrato una diminuzione del 25% nella escrezione NTx nei gruppi supplementati con VitVOO rispetto ai gruppi trattati con PlaVOO; quindi meno NTx nelle urine significa un migliore assorbimento del calcio nelle ossa. In conclusione, questi dati confermano l'ipotesi secondo la quale l'uso di VitVOO possa essere un utile trattamento per migliorare la densità ossea e la resistenza alle fratture, anche in età pediatrica, quando siamo di fronte ad uno scarso accrescimento corporeo

NAD⁺ Homeostasis and NAD⁺-Consuming Enzymes: Implications for Vascular Health

Nicotinamide adenine dinucleotide (NAD+) is a ubiquitous metabolite that takes part in many key redox reactions. NAD+ biosynthesis and NAD+-consuming enzymes have been attracting markedly increasing interest since they have been demonstrated to be involved in several crucial biological pathways, impacting genes transcription, cellular signaling, and cell cycle regulation. As a consequence, many pathological conditions are associated with an impairment of intracellular NAD+ levels, directly or indirectly, which include cardiovascular diseases, obesity, neurodegenerative diseases, cancer, and aging. In this review, we describe the general pathways involved in the NAD+ biosynthesis starting from the different precursors, analyzing the actual state-of-art of the administration of NAD+ precursors or blocking NAD+-dependent enzymes as strategies to increase the intracellular NAD+ levels or to counteract the decline in NAD+ levels associated with ageing. Subsequently, we focus on the disease-related and age-related alterations of NAD+ homeostasis and NAD+-dependent enzymes in endothelium and the consequent vascular dysfunction, which significantly contributes to a wide group of pathological disorders

NAD+ Homeostasis and NAD+-Consuming Enzymes: Implications for Vascular Health

Nicotinamide adenine dinucleotide (NAD+) is a ubiquitous metabolite that takes part in many key redox reactions. NAD+ biosynthesis and NAD+-consuming enzymes have been attracting markedly increasing interest since they have been demonstrated to be involved in several crucial biological pathways, impacting genes transcription, cellular signaling, and cell cycle regulation. As a consequence, many pathological conditions are associated with an impairment of intracellular NAD+ levels, directly or indirectly, which include cardiovascular diseases, obesity, neurodegenerative diseases, cancer, and aging. In this review, we describe the general pathways involved in the NAD+ biosynthesis starting from the different precursors, analyzing the actual state-of-art of the administration of NAD+ precursors or blocking NAD+-dependent enzymes as strategies to increase the intracellular NAD+ levels or to counteract the decline in NAD+ levels associated with ageing. Subsequently, we focus on the disease-related and age-related alterations of NAD+ homeostasis and NAD+-dependent enzymes in endothelium and the consequent vascular dysfunction, which significantly contributes to a wide group of pathological disorders