Search results for "Uric acid."
showing 10 items of 337 documents
Ion–Molecule Rate Constants for Reactions of Sulfuric Acid with Acetate and Nitrate Ions
2022
Atmospheric nucleation from precursor gases is a significant source of cloud condensation nuclei in the troposphere and thus can affect the Earth's radiative balance. Sulfuric acid, ammonia, and amines have been identified as key nucleation precursors in the atmosphere. Studies have also shown that atmospheric ions can react with sulfuric acid to form stable clusters in a process referred to as ion-induced nucleation (IIN). IIN follows similar reaction pathways as chemical ionization, which is used to detect and measure nucleation precursors via atmospheric pressure chemical ionization mass spectrometers. The rate at which ions form clusters depends on the ion-molecule rate constant. Howeve…
Molecular Recognition by Hydrogen Bonding in Polyelectrolyte Multilayers
1997
Functional polyanions were prepared by copolymerization of sulfopropyl acrylate and sulfopropyl methacrylate with monomers bearing triaminopyrimidine or barbituric acid functionalities, respectively. Functionalized polyelectrolyte multilayers were assembled from these copolymers by stepwise alternating adsorption with poly(choline methacrylate). These multilayers are suited for molecular recognition of substrates that are complementary to the functional groups incorporated. Thus, multilayers containing triaminopyrimidine moieties selectively bind barbituric acid, and vice versa, when exposed to solutions of the 1:1 complex of barbituric acid and triaminopyrimidine. The molecular recognition…
Behavior of the total antioxidant status in a group of subjects with metabolic syndrome.
2014
AIM: Our purpose was to examine the total antioxidant status (TAS) in subjects with metabolic syndrome (MS) subdivided according to the presence or not of diabetes mellitus. METHODS: We enrolled 106 subjects (45 women, 61 men) with MS subsequently subdivided in diabetics (14 women, 29 men) and nondiabetics (31 women, 29 men). TAS was obtained using an Assay kit which relies on the ability of plasma antioxidant substances to inhibit the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline sulfonic acid) to the radical ABTS+. RESULTS: In the group of MS subjects a significant decrease in TAS (p<0.05) in comparison with normal controls was evident. This difference was present between normal subje…
Reduced secretion of proinflammatory cytokines of monosodium urate crystal‐stimulated monocytes in chronic renal failure: an explanation for infreque…
2000
In gouty arthritis, monosodium urate (MSU) crystals interact with monocytes and neutrophils to produce inflammatory reactions associated with acute synovitis. In patients with end-stage renal disease (ESRD), gouty arthritis is a rare condition despite often severe hyperuricaemia. We wondered whether differences in the secretion of proinflammatory cytokines by MSU crystal-stimulated monocytes might be one explanation for the low incidence of gouty arthritis in patients with ESRD compared with healthy controls.Thirteen patients with ESRD on intermittent haemodialysis treatment, six patients with chronic renal failure not yet on dialysis, and 15 age- and sex-matched healthy controls were exami…
Impaired plasma nitric oxide availability and extracellular superoxide dismutase activity in healthy humans with advancing age
2006
This study is aimed to verify the modifications of extracellular superoxide dismutase (EC-SOD) activity and its potential involvement on the mechanism responsible for the impairment of plasma nitric oxide (NO) availability occurring with advancing age in healthy humans. For this purpose, plasma samples were drawn from 40 healthy men, aged 20-92 years, in fasting state and used for measurements of stable end-product nitrite/nitrate (NOx), as expression of NO availability, EC-SOD activity, thiobarbituric acid reactive substances (TBARS) as marker of lipid peroxidation, Trolox equivalent antioxidant capacity (TEAC) as a measure of plasma total antioxidant capacity, and in vitro susceptibility …
Lipid Peroxidation, Nitric Oxide Metabolites, and Their Ratio in a Group of Subjects with Metabolic Syndrome
2014
Our aim was to evaluate lipid peroxidation, expressed as thiobarbituric acid-reactive substances (TBARS), nitric oxide metabolites (nitrite + nitrate) expressed asNOx, and TBARS/NOxratio in a group of subjects with metabolic syndrome (MS). In this regard we enrolled 106 subjects with MS defined according to the IDF criteria, subsequently subdivided into diabetic (DMS) and nondiabetic (NDMS) and also into subjects with a low triglycerides/HDL-cholesterol (TG/HDL-C) index or with a high TG/HDL-C index. In the entire group and in the four subgroups of MS subjects we found an increase in TBARS andNOxlevels and a decrease in TBARS/NOxratio in comparison with normal controls. Regarding all these …
Determination of ethyl sulfate – a marker for recent ethanol consumption – in human urine by CE with indirect UV detection
2006
A CE method for the determination of the ethanol consumption marker ethyl sulfate (EtS) in human urine was developed. Analysis was performed in negative polarity mode with a background electrolyte composed of 15 mM maleic acid, 1 mM phthalic acid, and 0.05 mM cetyltrimethylammonium bromide (CTAB) at pH 2.5 and indirect UV detection at 220 nm (300 nm reference wavelength). This buffer system provided selective separation conditions for EtS and vinylsulfonic acid, employed as internal standard, from urine matrix components. Sample pretreatment of urine was minimized to a 1:5 dilution with water. The optimized CE method was validated in the range of 5-700 mg/L using seven lots of urine. Intra-…
In vivoprooxidant state in Werner syndrome (WS): Results from three WS patients and two WS heterozygotes
2005
The hypothesis was tested that Werner syndrome (WS) phenotype might be associated with an in vivo prooxidant state. A set of redox-related endpoints were measured in three WS patients, two of their parents, and 99 controls within a study of some cancer-prone and/or ageing-related genetic disorders. The following analytes were measured: (a) leukocyte 8-hydroxy-2'-deoxyguanosine; (b) glutathione from whole blood, and (c) plasma levels of glyoxal, methylglyoxal, 8-isoprostane, and some plasma antioxidants (uric acid, ascorbic acid, alpha- and gamma-tocopherol). Leukocyte 8-hydroxy-2'-deoxyguanosine levels showed a significant increase in the 3 WS patients vs. 85 controls (p<10(-7)). The disulf…
Oxidative stress biomarkers in four Bloom syndrome (BS) patients and in their parents suggest in vivo redox abnormalities in BS phenotype.
2007
Objective: To evaluate an association of Bloom syndrome (BS) phenotype with an in vivo prooxidant state. Methods: The following endpoints were measured in 4 BS patients, their 6 parents, and 78 controls: a) leukocyte and urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG); b) blood glutathione (GSSG and GSH), c) plasma levels of some plasma antioxidants (uric acid, UA, ascorbic acid, AA, α- and γ-tocopherol), and of glyoxal (Glx) and methylglyoxal (MGlx). Results: Leukocyte 8-OHdG levels were significantly increased in the 4 BS patients vs. 40 controls (p = 0.04), while the urinary 8-OHdG levels were non-significantly increased in BS patients. Glutathione disulfide levels and GSSG/GSH ratio were s…
Associations of Birth Weight and Postnatal Weight Gain With Cardiometabolic Risk Parameters at 5 Years of Age
2014
The present prospective study assessed the impact of birth weight (BW) and postnatal weight gain on blood pressure and metabolic profile during the first 5 years of life. One hundred thirty-nine newborns (63 women) born at term after uncomplicated pregnancies and in the absence of perinatal illness were included. Subjects were divided according to size at birth in small, appropriate, and large for gestational age. After the initial evaluation on the second day of life, infants were followed up at 6 months and 2 and 5 years. Anthropometric parameters and blood pressure were measured at each visit and metabolic assessment was performed at 5 years of age. Among the BW groups, mothers did not d…