Identification of metabolic markers in patients with type 2 Diabetes by Ultrafast gas chromatography coupled to electronic nose. A pilot study

Metabolomics is a potential tool for the discovery of new biomarkers in the early diagnosis of diseases. An ultra-fast gas chromatography system equipped to an electronic nose detector (FGC eNose) was used to identify the metabolomic profile of Volatile Organic Compounds (VOCs) in type 2 diabetes (T2D) urine from Mexican population. A cross-sectional, comparative, and clinical study with translational approach was performed. We recruited twenty T2D patients and twenty-one healthy subjects. Urine samples were taken and analyzed by FGC eNose. Eighty-eight compounds were identified through Kovats's indexes. A natural variation of 30% between the metabolites, expressed by study groups, was observed in Principal Component 1 and 2 with a significant difference (p < 0.001). The model, performed through a Canonical Analysis of Principal coordinated (CAP), allowed a correct classification of 84.6% between healthy and T2D patients, with a 15.4% error. The metabolites 2-propenal, 2-propanol, butane- 2,3-dione and 2-methylpropanal, were increased in patients with T2D, and they were strongly correlated with discrimination between clinically healthy people and T2D patients. This study identified metabolites in urine through FGC eNose that can be used as biomarkers in the identification of T2D patients. However, more studies are needed for its implementation in clinical practice.     

FUROCOUMARIN-PHOTOSENSITIZEDHYDROXYLATION OF GUANOSINE IN RNA AND DNA

Abstract— Guanosine hydroxylation was used as a marker for assessing photooxidation of DNA and RNA sensitized by monofunctional and bifunctional furocoumarins. DNA or RNA, treated with sensitizer and UVA light, was enzymatically hydrolyzed, dephosphorylated and then analyzed by reversed-phase HPLC with electrochemical detection. Hydroxylated guanosine, i.e. 8-hydroxy-2'-deoxyguanosine (8-OHdG) or 8-hydroxyguanosine (8-OHG), was quantitated. 3-Carbethoxypsoralen (3-CP) was found to be an efficient photosensitizer for oxidation of guanosine in DNA, resulting in conversion of up to 0.4% of guanosine residues to 8-OHdG. In contrast, dramatically lower levels of guanosine hydroxylation were observed in 3-CP-photosensitized RNA. Psoralen was found to be a more efficient photosensitizer than angelicin in both DNA and RNA. Additional studies of oxidation of 3-CP-photosensitized DNA indicated that double-stranded DNA is 10 times more susceptible to photooxidation than single-stranded DNA, implicating 3-CP binding to DNA as an important mechanistic step in photooxidation of guanosine. The effects of D₂O and degassing with argon on photooxidation of guanosine in DNA sensitized by 3-CP were inconsistent with a mechanism involving ¹O₂. In addition, chelation of adventitious metal ions present in preparations of DNA photosensitized by 3-CP had no effect on hydroxylation of guanosine.     

Thermospray liquid chromatographic-mass spectrometric analysis of anti-AIDS nucleosides: quantification of 2',3'-dideoxycytidine in plasma samples.

Thermospray liquid chromatography-mass spectrometry was investigated as a method for quantification of 2',3'-dideoxycytidine (DDC) from human plasma. A stable isotope analog of DDC ([15N2,2H2]DDC) was used as an internal standard. Selected ion monitoring of the protonated molecular ions for DDC and the internal standard was used to record mass chromatograms. The areas of the peaks in the mass chromatograms were used for quantification. The detection limit of DDC in this assay was 50 pg on-column. The calibration curve was linear over the desired range, 0.25-20 ng/ml. The major advantages of this assay over others are: no derivatization, high sensitivity, high specificity and short assay time.     

Kinetic oscillations in the NO+CO reaction on the Pt(100) surface: an alternative reaction mechanism

Kinetic oscillations in the catalytic reduction of NO by CO on a reconstructing Pt(100) surface are simulated by using a dynamic Monte Carlo method. The simulation is based on the HS model and takes into account an alternative reaction mechanism arising from recent experimental findings for the catalytic reduction of No on Rh(111), which replaces the classical N+N recombination step by the formation of a (N-NO)(*) intermediary species for the production of molecular nitrogen. A synchronized mechanism and spatiotemporal patterns are observed during the oscillations. Oscillations are analyzed in terms of the controlling parameters involved in the reaction mechanism. Different values of these parameters lead to sustained, attenuated, and modulated oscillations.     

In vivo protective effect of beta-carotene against psoralen phototoxicity

The protective effect of β-carotene against PUVA- and UVB-induced erythema was determined in groups of albino female Osborne Mendel rats fed standard, placebo or β-carotene-fortified diets. After 13 weeks, the backs of selected animals were clipped and the animals received 8MOP orally, 20 mg/kg in corn oil, followed by 5 J/cm² UVA irradiation 2 h after dose. A significant β-carotene protective effect was observed against phototoxicity induced by 8MOP, as measured by erythema production. A correlation was noted between the observed protective effect and β-carotene serum and skin levels, determined by HPLC. No protective effect against erythema induced by UVB (0.7 J/cm²) was observed in animals fed the β-carotene-fortified diet. This report represents the first in vivo demonstration of a protective effect of dietary p-carotene against psoraten-induced phototoxicity. Possible mechanisms for the observed β-carotene-protective effect are discussed.     

Beitrag zur mikroskopischen Untersuchung und Identifizierung des Ergothioneins

Zusammenfassung Ergothionein wurde einer Untersuchung nach denKoflerschen Thermomikromethoden unterworfen. Neben der Ermittlung der üblichen für dieKofhrsche Identifizierungstabelle nötigen physikalischen Konstanten wurden auch einige kristalloptische Bestimmungen an den Ergothionein-Kristallen, die aus verschiedenen organischen Lösungsmitteln erhalten wurden, durchgeführt.

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Summary Ergothionein was studied by theKofler thermomicromethods. In addition to determining the usual physical constants required for theKofler Identification Table, several crystallographic determinations were made on the ergothionein crystals, which had been obtained from several organic solvents.

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Résumé L'ergothionéine a été l'objet de recherches par application des thermomicrométhodes deKofler. A côté de l'établissement des constantes physiques nécessaires figurant sur le tableau d'identification deKofler, on a effectué également quelques déterminations d'optique cristalline sur des cristaux d'ergothionéine obtenus dans divers solvants organiques.

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Dem Vorstand des minerulogischen Institutes der Universität Ljublja-na, Herrn Prof. Dr. J.Duhovnik, der uns die Ausführung kristMloptiseher Bestimmungen ermögliehte, sind wir zu aufriehtigem Dank verpflichtet.