The state-of-the-art determination of urinary nucleosides using chromatographic techniques “hyphenated” with advanced bioinformatic methods

Over the last decade metabolomics has gained increasing popularity and significance in life sciences. Together with genomics, transcriptomics and proteomics, metabolomics provides additional information on specific reactions occurring in humans, allowing us to understand some of the metabolic pathways in pathological processes. Abnormal levels of such metabolites as nucleosides in the urine of cancer patients (abnormal in relation to the levels observed in healthy volunteers) seem to be an original potential diagnostic marker of carcinogenesis. However, the expectations regarding the diagnostic value of nucleosides may only be justified once an appropriate analytical procedure has been applied for their determination. The achievement of good specificity, sensitivity and reproducibility of the analysis depends on the right choice of the phases (e.g. sample pretreatment procedure), the analytical technique and the bioinformatic approach. Improving the techniques and methods applied implies greater interest in exploration of reliable diagnostic markers. This review covers the last 11 years of determination of urinary nucleosides conducted with the use of high-performance liquid chromatography in conjunction with various types of detection, sample pretreatment methods as well as bioinformatic data processing procedures

Simultaneous determination of creatinine and pseudouridine concentrations in bovine plasma by reversed-phase liquid chromatography with photodiode array detection

A simple, rapid method for the simultaneous determination of creatinine and pseudouridine in bovine plasma is described. Plasma was de-proteinised, concentrated, and chromatographed for 15 min on a C-18 column. Analytes were detected at an optimum wavelength (262 nm) and the internal standard (cimetidine) was detected at 220 nm. The pH of analysis was between 6.5 and 7 where both analytes exist in single chemical forms giving maximum accuracy. Recoveries of both analytes were above 96%. Lowest detectable amounts of creatinine and pseudouridine were 0.28 nmol and 9.0 pmol, and the typical levels detected (+/-SD) were 60 (+/-2.8) and 2.3 (+/-0.10) mumol/L, respectively. (C) 2002 Elsevier Science B.V. All rights reserved

Effect of dietary tocopherols and tocotrienols on the antioxidant status and lipid stability of chicken

We determined the effect of dietary tocopherols and tocotrienols on the lipid stability of pre-cooked chicken breast and thigh. The birds were supplemented with one of two doses of a commercial mixture of tocopherols and tocotrienols (Oryza1, Oryza2) or one of two doses of all-rac alpha-tocopherol acetate (Toc1, Toc2). Diets were formulated so that Oryza1 and Toc1 and Oryza2 and Toc2 contained similar tocopherol concentrations. No quantifiable amounts of tocotrienols were found in either breast or thigh muscles. Tocotrienols present in the diet reduced muscle alpha-tocopherol concentration. The effect of Oryza1 on the tocopherol content in muscle and on its lipid stability was not significant. The Oryza2, Toc1 and Toc2 diets increased the alpha- and gamma-tocopherol in breast and thigh muscles and enhanced their lipid stability. This improvement was only due to the antioxidant action of the tocopherols. Lipid stability of pre-cooked chicken was not enhanced by adding tocotrienols to a tocopherol supplement. (C) 2004 Elsevier Ltd. All rights reserved

Beta-Endorphin 1-31 Biotransformation and cAMP Modulation in Inflammation

A large body of evidence now exists for the immune cell expression, production, and the release of beta-endorphin (BE 1-31) within inflamed tissue. The inflammatory milieu is characterised by increased acidity, temperature and metabolic activity. Within these harsh conditions BE 1-31 is even more susceptible to increased enzymatic degradation over that of plasma or other non-injured tissue. To elucidate the biotransformation pathways of BE 1-31 and provide an insight to the impact of inflamed tissue environments, BE 1-31 and three of its major N-terminal fragments (BE 1-11, BE 1-13 and BE 1-17) were incubated in inflamed tissue homogenates at pH 5.5 for 2 hrs. In addition, the potency of BE 1-31 and five main N--terminal fragments (BE 1-9, BE 1-11, BE 1-13, BE 1-17, BE 1-20) was assessed at mu-opioid receptors (MOR), delta-opioid receptors (DOR), and kappa-opioid receptors (KOR). Opioid receptor potency was investigated by examining the modulation of forskolin induced cAMP accumulation. The majority of the N-terminal fragment of BE 1-31 had similar efficacy to BE 1-31 at MOR. The shortest of the major N-terminal fragments (BE 1-9), had partial agonist activity at MOR but possessed the highest potency of all tested peptides at DOR. There was limited effect for BE 1-31 and the biotransformed peptides at KOR. Major N-terminal fragments produced within inflamed tissue have increased presence within inflamed tissue over that of the parent molecule BE 1-31 and may therefore contribute to BE 1-31 efficacy within disease states that involve inflammation