Screening method for the simultaneous determination of allantoin and uric acid from dried blood spots.

Uric acid and its oxidation product allantoin are excellent biomarkers of oxidative stress in humans. Currently, there are high requirements not only for tests monitoring oxidative stress but also for screening laboratory tests in general. The highest demand is imposed on the simplest sampling, easy transport of the sample, and the shortest possible analysis time.

Dried blood spot as an alternative sample for screening of fatty acid, amino acid, and keto acid metabolism in humans.

Dried blood spot (DBS) is a simple and noninvasive sample collection technique allowing self-collection at home. It can be used as an alternative sample for the screening of metabolism in humans because changes in the levels of some fatty acids (FAs), amino acids (AAs), and keto acids (KAs) can be associated with metabolic disorders (e.g.

Determination of selected α-keto acids in dried blood samples using HPLC with fluorescence detection.

The determination of α-keto acids derived from amino acids is currently the most reliable approach for the diagnosis of some congenital metabolic diseases. An HPLC method for the simultaneous measurement of selected α-keto acids in dried blood samples has been developed and evaluated. Blood spot samples from a group of healthy blood donors were collected onto #903 Specimen Collection Paper.

The issue of HPLC determination of endogenous lipoic acid in human plasma.

Lipoic acid (LA) is used extensively as a therapeutic agent for the treatment of various diseases. Many methods have been reported for the determination of LA plasma levels and its metabolites after its supplementation, but available information concerning endogenous plasma levels is still scarce. Studies which directly focused on determining the endogenous plasma levels provided highly controversial results, <4.

Determination of Selected Amino Acids in Serum of Patients with Liver Disease.

Background: The determination of amino acids can be a reliable approach for extended diagnosis of liver diseases. This is because liver disease can be a cause of impaired amino acid metabolism. Therefore, a method for the determination of serum amino acids, applicable for clinical purposes, is necessary.

Determination of selected fatty acids in dried sweat spot using gas chromatography with flame ionization detection.

A method is described for the determination of fatty acids in dried sweat spot and plasma samples using gas chromatography with flame ionization detection. Plasma and dried sweat spot samples were obtained from a group of blood donors. The sweat was collected from each volunteer during exercise.

An HPLC method for the determination of selected amino acids in human embryo culture medium.

A method for the determination of selected amino acids in culture medium using HPLC with fluorescence detection is described. Twenty hours after intra-cytoplasmic sperm injection, one randomly selected zygote was transferred to the culture medium. After incubation (72 h after fertilization), the culture medium in which the embryo was incubated and blank medium was immediately stored at -80°C.

Alterations in protein and amino acid metabolism in rats fed a branched-chain amino acid- or leucine-enriched diet during postprandial and postabsorptive states.

Background: Many people believe in favourable effects of branched-chain amino acids (BCAAs; valine, leucine, and isoleucine), especially leucine, on muscle protein balance and consume BCAAs for many years. We determined the effects of the chronic intake of a BCAA- or leucine-enriched diet on protein and amino acid metabolism in fed and postabsorptive states.

Methods: Rats were fed a standard diet, a diet with a high content of valine, leucine, and isoleucine (HVLID), or a high content of leucine (HLD) for 2 months.

An Assay of Selected Serum Amino Acids in Patients with Type 2 Diabetes Mellitus.

Background: Amino acids are the building blocks of proteins. In case of insulin resistance, which is typical for type 2 diabetes mellitus (T2DM), proteolysis is increased and protein synthesis is decreased; therefore, we can observe changes in the levels of amino acids in diabetics vs. non-diabetics.

The ratio of oxidized and reduced forms of selected antioxidants as a possible marker of oxidative stress in humans.

Oxidative stress is an imbalance between reactive oxygen species exposure and the ability of organisms to detoxify the reactive intermediates and to repair the oxidative damage of biologically important molecules. Many clinical studies of oxidative stress unfortunately provide conflicting and contradictory results. The ability of antioxidant systems to adequately respond to oxidative stress can be used in laboratory diagnostics.

Determination of Total Glutathione in Dried Blood Spot Samples Using a High-Performance Liquid Chromatography.

A method is described for the determination of total glutathione (TGSH) in dried blood spot (DBS) samples using high-performance liquid chromatography with fluorescence detection. Whole blood and DBS samples were obtained from a group of blood donors. After GSH reduction with dithiothreitol and protein precipitation with ethanol, the samples were derivatized with naphthalene-2,3-dicarboxaldehyde to form a very stable, highly fluorescent derivative.

The determination of ascorbic acid and uric acid in human seminal plasma using an HPLC with UV detection.

Oxidative stress has been proposed as one of the potential causes for infertility in men. Ascorbic acid and uric acid play important role in protection of spermatozoa against free radicals. A method for the simultaneous determination of ascorbic acid and uric acid in human seminal plasma using HPLC with UV detection and investigation their clinical significance as antioxidants protecting male germ cells against oxidative damage are described.

Inverse correlation between plasma Beta-carotene and interleukin-6 in patients with advanced coronary artery disease.

The interrelationships between plasma beta-carotene, alpha-tocopherol, and the level of systemic inflammation and oxidative stress were investigated in patients with advanced coronary artery disease (CAD). Plasma beta-carotene, alpha-tocopherol, malondialdehyde, free radicals, interleukin-6, high sensitive C-reactive protein levels, and other risk factors of CAD were determined in a group of patients with advanced CAD [significant stenosis according to coronarographic examination (n=91) and a control group of examined patients with coronary arteries with no stenosis (n=49)]. Between-group differences in continuous variables were analyzed with the Hotelling T2-test (software NCSS2000), analyses of correlation matrix with the software STATISTICA.

Acute hyperammonemia activates branched-chain amino acid catabolism and decreases their extracellular concentrations: different sensitivity of red and white muscle.

Hyperammonemia is considered to be the main cause of decreased levels of the branched-chain amino acids (BCAA), valine, leucine, and isoleucine, in liver cirrhosis. In this study we investigated whether the decrease in BCAA is caused by the direct effect of ammonia on BCAA metabolism and the effect of ammonia on BCAA and protein metabolism in different types of skeletal muscle. M.

Determination of phenylalanine and tyrosine in plasma and dried blood samples using HPLC with fluorescence detection.

The determination of phenylalanine and tyrosine is presently the most reliable direct approach to the diagnosis of phenylketonuria. An HPLC method for the simultaneous measurement of phenylalanine and tyrosine in samples of dried blood spots and plasma has been developed and evaluated. We have used an inherent fluorescence of both phenylalanine and tyrosine.

Determination of 25-hydroxyvitamin D3 in human plasma using HPLC with UV detection based on SPE sample preparation.

Interest in the metabolism and physiological action of vitamin D is increased exponentially. The most important metabolites of vitamin D are 25-hydroxyvitamin and 1,25-dihydroxyvitamin D(3). The aim of the study was to develop a rapid and simple HPLC method for the measurement of 25-hydroxyvitamin D(3) in human plasma.

Determination of branched chain amino acids, methionine, phenylalanine, tyrosine and alpha-keto acids in plasma and dried blood samples using HPLC with fluorescence detection.

Background: The determination of branched chain amino acids [BCAA; valine (Val), leucine (Leu), isoleucine (Ile)], alpha-keto acids derived from BCAA [BCKA; alpha-ketoisovaleric acid (KIV), alpha-ketoisocaproic acid (KIC), alpha-ketomethylvaleric acid (KMV)], methionine (Met), phenylalanine (Phe) and tyrosine (Tyr) is currently the most reliable approach for the diagnosis of maple syrup urine disease (MSUD), hypermethioninemia, phenylketonuria (PKU) and tyrosinemia. The aim of this study was to develop rapid and simple HPLC methods for measurement of BCAA, Met, Phe, Tyr and BCKA in plasma and dried blood samples.

Methods: Samples of peripheral venous blood with EDTA as anticoagulant were obtained from a group of healthy blood donors (n=70, 35 females, 27-41 years of age and 35 males, 28-43 years of age).

Determination of ascorbic acid in human plasma with a view to stability using HPLC with UV detection.

A method for the measurement of ascorbic acid using HPLC with UV detection and investigation into the protein precipitation techniques with regard to stability and recovery are described. The effectiveness of various protein precipitants was tested. Stability of ascorbic acid samples for analysis was investigated over 10 h.

Allantoin as a marker of oxidative stress in human erythrocytes.

Background: Uric acid is the final product of purine metabolism in humans. It was determined that this compound has important antioxidative properties and it may be oxidized to allantoin by various reactive oxygen species. Therefore, the measurement of allantoin may be useful for the determination of oxidative stress in humans.

Evaluation of oxidative stress and inflammation in obese adults with metabolic syndrome.

Background: Obesity and metabolic syndrome increase the risk of cardiovascular morbidity and mortality. Oxidative stress seems to be involved in the pathophysiology of diabetes and cardiovascular complications of metabolic syndrome. The aim of our study was to evaluate the level of oxidative stress and inflammation in obese adults with and without metabolic syndrome.

Ubiquinol-10/lipids ratios in consecutive patients with different angiographic findings.

Objective: Information concerning un-supplemented plasma concentrations of ubiquinol-10 in coronary artery disease patients is still controversial. The aim of this study is to determine the levels of plasma ubiquinol-10 and ratios of ubiquinol-10 to plasma lipids in consecutive patients with different angiographic findings.

Subjects And Methods: Thirty-six consecutive patients who underwent coronary angiography were split in two groups with different atherosclerotic changes.

Determination of reduced and oxidized glutathione in biological samples using liquid chromatography with fluorimetric detection.

A HPLC method for determination of both reduced (GSH) and oxidized (GSSG) glutathione in plasma, whole blood and rat hepatocytes has been developed and evaluated. Reduced glutathione reacts with orthophthaldehyde (OPA) to form a stable, highly fluorescent tricyclic derivate at pH 8, while GSSG reacts with OPA at pH 12. At measurement of GSSG, GSH was complexed to N-ethylmaleimide.

The model of D-galactosamine-induced injury of rat hepatocytes in primary culture.

D-galactosamine (GalN) is a highly selective hepatotoxin that causes liver damage similar to human viral hepatitis via depletion of uridine nucleotides, which subsequently diminishes synthesis of RNA and proteins. Model of galactosamine hepatotoxicity is frequently used in animal experiments in vitro. The purpose of our study was to establish the model of GalN-induced hepatocyte injury in in vitro conditions using primocultures of rat hepatocytes as an important pre-requisite for further experiments in which we would like to study potential hepatoprotective effect of various substances.

Monitoring of antioxidant properties of uric acid in humans for a consideration measuring of levels of allantoin in plasma by liquid chromatography.

Uric acid is the end product of purine metabolism in humans. It has been pointed out that uric acid acts as an antioxidant and is capable to react with biologically relevant oxidants to form allantoin. Therefore, measurement of allantoin in humans was proposed as a marker of oxidative stress.

Protective effect of S-adenosylmethionine on cellular and mitochondrial membranes of rat hepatocytes against tert-butylhydroperoxide-induced injury in primary culture.

Accumulating evidence that administration of S-adenosylmethionine (SAMe) protects hepatocytes against oxidative stress-mediated injury led us to evaluate the effect of SAMe on hepatocyte injury induced in culture by oxidant substance tert-butylhydroperoxide (1.5 mM tBHP) with regard to prevent mitochondrial injury. The pretreatment of hepatocyte culture with SAMe in doses of 0.