Targeted and untargeted urinary metabolomics of alkaptonuria patients using ultra high-performance liquid chromatography-tandem mass spectrometry.

Alkaptonuria (AKU) is a rare autosomal-recessive disease which is characterized through black urine and ochronosis. It is caused by deficiency of the enzyme Homogentisate 1,2-dioxygenase in the Phenylalanine/Tyrosine degradation pathway which leads to the accumulation of Homogentisic acid (HGA). Urine was provided by AKU patients and healthy controls.

Hemin promotes platelet activation and plasma membrane disintegration regulated by the subtilisin-like proprotein convertase furin.

Platelet activation plays a critical role in thrombosis and hemostasis. Several pathophysiological situations lead to hemolysis, resulting in the liberation of free ferric iron-containing hemin. Hemin has been shown to activate platelets and induce thrombo-inflammation.

Comprehensive Coverage of Glycolysis and Pentose Phosphate Metabolic Pathways by Isomer-Selective Accurate Targeted Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Assay.

The accurate liquid chromatography-tandem mass spectrometry analysis of phosphorylated isomers from glycolysis and pentose phosphate pathways is a challenging analytical problem in metabolomics due to extraction problems from the biological matrix, adherence to stainless steel surfaces leading to tailing in LC, and incomplete separation of hexose and pentose phosphate isomers. In this study, we present a targeted HILIC-ESI-MS/MS method based on a BEH amide fully porous 1.7 μm particle column with an inert surface coating of column hardware and multiple reaction monitoring (MRM) acquisition fully covering the glycolysis and pentose phosphate pathway metabolites.

Solving the retention time repeatability problem of hydrophilic interaction liquid chromatography.

Hydrophilic interaction (liquid) chromatography (HILIC) has become the first choice LC mode for the separation of hydrophilic analytes. Numerous studies reported the poor retention time repeatability of HILIC. The problem was often ascribed to slow equilibration and insufficient re-equilibration time to establish the sensitive semi-immobilized water layer at the interface of the polar stationary phase and the bulk mobile phase.

mitoBK is functionally expressed in murine and human breast cancer cells and potentially contributes to metabolic reprogramming.

Alterations in the function of K channels such as the voltage- and Ca-activated K channel of large conductance (BK) reportedly promote breast cancer (BC) development and progression. Underlying molecular mechanisms remain, however, elusive. Here, we provide electrophysiological evidence for a BK splice variant localized to the inner mitochondrial membrane of murine and human BC cells (mitoBK).

Quantitative analysis of the glutathione pathway cellular metabolites by targeted liquid chromatography-tandem mass spectrometry.

Glutathione, its biosynthesis intermediates, and other thiol metabolites are of central relevance for the redox homeostasis of cells. Their analysis is critical due to the facile interconversion of redox pairs during sampling, sample preparation, and data acquisition, in particular in the electrospray ionization interface. In this work, we propose a fast-targeted liquid chromatography-tandem mass spectrometry method to accurately analyze 14 metabolites from the glutathione pathway.

Isomer selectivity of one- and two-dimensional approaches of mixed-mode and hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry for sugar phosphates of glycolysis and pentose phosphate pathways.

In this study, the chromatographic behavior of mixed-mode and hydrophilic interaction liquid chromatography (HILIC) with the mixed-mode HILIC/strong anion-exchange (SAX) column HILICpak VT-50 2D and the two HILIC columns Atlantis Premier BEH Z-HILIC and Acquity Premier BEH Amide was assessed with regard to their separation capability of the metabolites from the glycolysis and pentose phosphate pathways. Chromatographic conditions were evaluated with the aim of achieving separation of the isomeric glycolytic phosphorylated carbohydrate metabolites free from isomeric interferences and thus allowing for selective targeted analysis by liquid chromatography with tandem mass spectrometry (MS/MS) using multiple reaction monitoring acquisition. The effects of pH values (8.

Branched medium-chain fatty acid profiling and enantiomer separation of anteiso-forms of teicoplanin fatty acyl side chain RS3 using UHPLC-MS/MS with polysaccharide columns.

This work reports on targeted UHPLC-tandem mass spectrometry methods for the chiral separation of anteiso-methyl branched fatty acids (aiFAs). The methods involve precolumn derivatization with 1-naphthylamine and chiral separation on Chiralpak IG-U. anteiso-Methyl branched fatty acids with up to eight carbons can be separated.

Metabolic profiling workflow for cell extracts by targeted hydrophilic interaction liquid chromatography-tandem mass spectrometry.

In this study, a targeted approach with wide metabolite coverage was developed for cellular metabolomic analysis using a UHPLC-QTrap-MS system operated in the scheduled multiple reaction monitoring (sMRM) mode. MRM ion pairs were acquired from HeLa cell samples through untargeted analysis using UHPLC-QTOF-MS with SWATH acquisition complemented by missing metabolites from pathway databases. Four different cell extraction protocols were studied and compared based on an experiment series involving the calculation of individual metabolite recoveries (pre/post extraction spiking U-C isotope-labeled standards), with a Methanol/Water extraction mixture (1:1; v/v) showing the best results.

Towards enantioselective ultrahigh performance liquid chromatography-mass spectrometry-based metabolomics of branched-chain fatty acids and anteiso-fatty acids under reversed-phase conditions using sub-2-μm amylose- and cellulose-derived chiral stationary phases.

Branched-chain fatty acids (BCFAs) are mostly saturated fatty acids with one or more methyl, seldom ethyl, branches in the alkyl chain. They are derived from branched-chain amino acids, ruminant-derived food, or biosynthetic side products of acetyl-CoA carboxylase. They possess iso- (branching at penultimate carbon) and anteiso-fatty acid structure (branching at antepenultimate carbon) or are branched at any other position of the carbon chain.

[Dilemmas in indications for emergency revision surgery of postoperative complications in abdominal surgery - contribution to the problem].

The percentage of complications following an interval or emergency operative interventions in the abdomen is different and depends on several factors: -Proper indication for surgery -Experience of the surgical team, anesthesia -Extent of pathological changes; -patient's general condition (presence of associated diseases, capacity of the cardiovascular system, a.o.).

[Possibilities of traffic-injury prevention using seat belts and their disadvantages].

As a result of the increasing number of serious injuries, and/or deaths caused by automobile accidents, seatbelts, along with other safety items are installed in cars. The idea of having automobile seatbelts came from the aircraft seatbelt. In our country there is no law requiring installation of seatbelts in all automobiles.