This study explored the short-term effects of vitamin K2 (VK2) supplementation on biochemical parameters (vitamin D, vitamin E, vitamin A, alkaline phosphatase, calcium, phosphorus (P), magnesium, metallothionein, triglycerides, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and lipoprotein fractions (albumin, HDL, very low-density lipoprotein (VLDL), LDL, and chylomicrons). A short-term experiment (24 h, six probands) was performed to track changes in VK2 levels after a single-dose intake (360 μg/day). Liquid chromatography-tandem mass spectrometry was used to monitor vitamin K levels (menaquinone-4 (MK-4), menaquinone-7 (MK-7), and vitamin K1 [VK1]) with a limit of detection of 1.9 pg/mL for VK1 and 3.8 pg/mL for the two forms of VK2. Results showed that MK-7 levels significantly increased within 2-6 h post-administration and then gradually declined. MK-4 levels were initially low, showing a slight increase, whereas VK1 levels rose initially and then decreased. Biochemical analyses indicated no significant changes in sodium, chloride, potassium, calcium, magnesium, albumin, or total protein levels. A transient increase in P was observed, peaking at 12 h before returning to baseline. Agarose gel electrophoresis of lipoprotein fractions revealed distinct chylomicron bands and variations in VLDL and HDL mobility, influenced by dietary lipids and VK2 supplementation. These findings suggest effective absorption and metabolism of MK-7 with potential implications for bone metabolism and cardiovascular health.
- MeSH
- chromatografie kapalinová metody MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- lipoproteiny * krev MeSH
- potravní doplňky * analýza MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vitamin K 2 * analogy a deriváty krev MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Multidimensional chromatography coupled to tandem mass spectrometry (MS/MS), including simple sample preparation with protein precipitation, anion conversion with ammonium hydroxide, and solid-phase extraction using mixed-mode anion exchange in a 96-well plate format, has been validated for rapid simultaneous analysis of human insulin and its six analogs (lispro, glulisine, glargine, degludec, detemir, and aspart) in human plasma. This method is critical for clinical diagnostics, forensic investigations, and anti-doping efforts due to the widespread use of these substances. In the present study, improved chromatographic resolution was achieved using a first-dimension trap-and-elute configuration with an XBridge C18 (2.1 × 20 mm, 3.5 μm) trap column combined with second dimension separation on a Cortecs Ultra-High-Performance Liquid Chromatography (UHPLC) C18+ (2.1 × 100 mm, 1.6 μm) analytical column implemented within a two-dimensional-LC-MS/MS system. The total chromatographic run time was 11 min. This setup increases both the resolution and sensitivity of the method. A mobile phase consisting of 0.8% formic acid (FA) in water and 0.7% FA in acetonitrile was used for gradient elution. Bovine insulin was used as the internal standard. MS detection was performed in positive electrospray ionization mode, and the ion suppression due to matrix effects was evaluated. Validation criteria included linearity, precision, accuracy, recovery, lower limit of quantitation, matrix effect, and stability tests with and without protease inhibitor cocktail under different conditions (short-term stability, long-term stability, and freeze-thaw stability). The concentration range for all insulins was 50-15 000 pg/mL, with limits of quantification below the therapeutic reference range for all analytes. Intra-run precision ranged from 1.1% to 5.7%, inter-run precision from 0.7% to 5.9%, and overall recovery from 96.9% to 114.3%. The validated method has been implemented successfully by the Department of Forensic Medicine at our hospital for the investigation of unexplained deaths.
Epilepsy, affecting over 50 million people globally, presents a significant neurological challenge. Effective prevention of epileptic seizures relies on proper administration and monitoring of Anti-Seizure Medication (ASMs). Therapeutic Drug Monitoring (TDM) ensures optimal dosage adjustment, minimizing adverse effects and potential drug interactions. While traditional venous blood collection for TDM may be stressful, emerging alternative sampling methods, particularly Dried Blood Spot (DBS) or oral fluid offer less invasive way of sampling. This study aimed to develop and validate an analytical method for the determination of lamotrigine in such alternative samples. The sample, either DBS or oral fluid, was subjected to extraction, evaporation, and reconstitution in 15 % acetonitrile containing 0.1 % formic acid. A Kinetex C18 Polar column was used for liquid chromatographic separation and MS in ESI+ mode was used for detection and quantitation of lamotrigine using an isotopically labelled internal standard according to EMA guidelines. The calibration range of the developed method enables the determination of lamotrigine in the concentration range of 1-30 μg/mL in DBS and 0.5-20 μg/mL in oral fluid. Oral fluid and DBS samples from patients treated with lamotrigine analysed by the developed method were compared to plasma concentrations measured by the hospital's accredited laboratory. Preliminary results indicate a promising potential for these alternative matrices in clinical TDM applications. By offering a less invasive sampling approach, this method improves the accessibility and safety of pharmacotherapy for epilepsy patients. The results of this study lay the foundation for further clinical applications by implementing alternative matrix TDM, which may significantly advance personalized care in epilepsy management.
- MeSH
- antikonvulziva * analýza krev MeSH
- chromatografie kapalinová metody MeSH
- epilepsie farmakoterapie MeSH
- kalibrace MeSH
- kapalinová chromatografie-hmotnostní spektrometrie MeSH
- lamotrigin * analýza krev MeSH
- lidé MeSH
- limita detekce MeSH
- monitorování léčiv * metody MeSH
- reprodukovatelnost výsledků MeSH
- sliny * chemie MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- test suché kapky krve * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
The precise and unambiguous detection and quantification of internal RNA modifications represents a critical step for understanding their physiological functions. The methods of direct RNA sequencing are quickly developing allowing for the precise location of internal RNA marks. This detection is, however, not quantitative and still presents detection limits. One of the biggest remaining challenges in the field is still the detection and quantification of m6A, m6Am, inosine, and m1A modifications of adenosine. The second intriguing and timely question remaining to be addressed is the extent to which individual marks are coregulated or potentially can affect each other. Here, we present a methodological approach to detect and quantify several key mRNA modifications in human total RNA and in mRNA, which is difficult to purify away from contaminating tRNA. We show that the adenosine demethylase FTO primarily targets m6Am marks in noncoding RNAs in HEK293T cells. Surprisingly, we observe little effect of FTO or ALKBH5 depletion on the m6A mRNA levels. Interestingly, the upregulation of ALKBH5 is accompanied by an increase in inosine level in overall mRNA.
- MeSH
- adenosin * analogy a deriváty metabolismus genetika analýza MeSH
- alfa-ketoglutarát-dependentní dioxygenasa, AlkB homolog 5 * metabolismus genetika MeSH
- chromatografie kapalinová metody MeSH
- gen pro FTO * metabolismus genetika MeSH
- HEK293 buňky MeSH
- inosin * metabolismus genetika MeSH
- kapalinová chromatografie-hmotnostní spektrometrie MeSH
- lidé MeSH
- messenger RNA * genetika metabolismus MeSH
- posttranskripční úpravy RNA MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
While the use of food additives is common manufacturing practice, the levels used in food have to be compliant with the prescribed legislation. For fast control of present levels of food additives in products, ultra-high performance liquid chromatography coupled to tandem mass spectrometry with a triple quadrupole linear ion trap (QTRAP) mass analyser was applied to develop a method for the simultaneous determination of 41 frequently added food additives and flavourings, including 16 water-soluble colourants, 14 illegal dyes, 7 sweeteners, 2 preservatives, and 2 purine alkaloids. The method was validated using energy drink, chilli powder, condiment, and jelly sweets as food sample matrices. The average recovery values were in the range of 70‒120%, and the relative standard deviations were less than 10% for the majority of the analytes. The validated method was applied for the analysis of 134 samples from the Czech market.
- MeSH
- analýza potravin * metody MeSH
- chuťové esence analýza MeSH
- kapalinová chromatografie-hmotnostní spektrometrie MeSH
- kontaminace potravin * analýza MeSH
- lidé MeSH
- limita detekce MeSH
- nápoje * analýza MeSH
- potravinářské přísady * analýza MeSH
- reprodukovatelnost výsledků MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
- Geografické názvy
- Česká republika MeSH
Fast Photochemical Oxidation of Proteins (FPOP) is a promising technique for studying protein structure and dynamics. The quality of insight provided by FPOP depends on the reliability of the determination of the modification site. This study investigates the performance of two search engines, Mascot and PEAKS, for the data processing of FPOP analyses. Comparison of Mascot and PEAKS of the hemoglobin--haptoglobin Bruker timsTOF data set (PXD021621) revealed greater consistency in the Mascot identification of modified peptides, with around 26% of the IDs being mutual for all three replicates, compared to approximately 22% for PEAKS. The intersection between Mascot and PEAKS results revealed a limited number (31%) of shared modified peptides. Principal Component Analysis (PCA) using the peptide-spectrum match (PSM) score, site probability, and peptide intensity was applied to evaluate the results, and the analyses revealed distinct clusters of modified peptides. Mascot showed the ability to assess confident site determination, even with lower PSM scores. However, high PSM scores from PEAKS did not guarantee a reliable determination of the modification site. Fragmentation coverage of the modification position played a crucial role in Mascot assignments, while the AScore localizations from PEAKS often become ambiguous because the software employs MS/MS merging.
Microflow liquid chromatography interfaced with mass spectrometry (μLC-MS/MS) is increasingly applied for high-throughput profiling of biological samples and has been proven to have an acceptable trade-off between sensitivity and reproducibility. However, lipidomics applications are scarce. We optimized a μLC-MS/MS system utilizing a 1 mm inner diameter × 100 mm column coupled to a triple quadrupole mass spectrometer to establish a sensitive, high-throughput, and robust single-shot lipidomics workflow. Compared to conventional lipidomics methods, we achieve a ∼4-fold increase in response, facilitating quantification of 351 lipid species from a single iPSC-derived cerebral organoid during a 15 min LC-MS analysis. Consecutively, we injected 303 samples over ∼75 h to prove the robustness and reproducibility of the microflow separation. As a proof of concept, μLC-MS/MS analysis of Alzheimer's disease patient-derived iPSC cerebral organoid reveals differential lipid metabolism depending on APOE phenotype (E3/3 vs E4/4). Microflow separation proves to be an environmentally friendly and cost-effective method as it reduces the consumption of harmful solvents. Also, the data demonstrate robust, in-depth, high-throughput performance to enable routine clinical or biomedical applications.
- MeSH
- apolipoproteiny E MeSH
- chromatografie kapalinová metody MeSH
- fenotyp MeSH
- kapalinová chromatografie-hmotnostní spektrometrie * MeSH
- lidé MeSH
- lipidomika MeSH
- reprodukovatelnost výsledků MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Lipidomics and metabolomics communities comprise various informatics tools; however, software programs handling multimodal mass spectrometry (MS) data with structural annotations guided by the Lipidomics Standards Initiative are limited. Here, we provide MS-DIAL 5 for in-depth lipidome structural elucidation through electron-activated dissociation (EAD)-based tandem MS and determining their molecular localization through MS imaging (MSI) data using a species/tissue-specific lipidome database containing the predicted collision-cross section values. With the optimized EAD settings using 14 eV kinetic energy, the program correctly delineated lipid structures for 96.4% of authentic standards, among which 78.0% had the sn-, OH-, and/or C = C positions correctly assigned at concentrations exceeding 1 μM. We showcased our workflow by annotating the sn- and double-bond positions of eye-specific phosphatidylcholines containing very-long-chain polyunsaturated fatty acids (VLC-PUFAs), characterized as PC n-3-VLC-PUFA/FA. Using MSI data from the eye and n-3-VLC-PUFA-supplemented HeLa cells, we identified glycerol 3-phosphate acyltransferase as an enzyme candidate responsible for incorporating n-3 VLC-PUFAs into the sn1 position of phospholipids in mammalian cells, which was confirmed using EAD-MS/MS and recombinant proteins in a cell-free system. Therefore, the MS-DIAL 5 environment, combined with optimized MS data acquisition methods, facilitates a better understanding of lipid structures and their localization, offering insights into lipid biology.
- MeSH
- data mining * metody MeSH
- fosfatidylcholiny metabolismus chemie MeSH
- HeLa buňky MeSH
- hmotnostní spektrometrie metody MeSH
- lidé MeSH
- lipidomika * metody MeSH
- lipidy chemie analýza MeSH
- metabolomika metody MeSH
- nenasycené mastné kyseliny metabolismus chemie MeSH
- software MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Ocrelizumab is a second generation recombinant humanized IgG1 monoclonal antibody used for the treatment of multiple sclerosis that selectively target B cells expressing the CD20 antigen. This study aimed to develop and validate a UPLC-MS/MS method for quantification of ocrelizumab in human serum, which can be used in clinical applications for therapeutic drug monitoring. The analysis of ocrelizumab was performed using a bottom-up approach on a liquid chromatography coupled to tandem mass spectrometry detection. The method involved immunoglobulin precipitation with cold methanol followed by peptide digestion with trypsin. The resulting specific peptides were separated on an Acquity UPLC BEH C18 column at 55 °C using gradient elution. The method was validated according to European Medicines Agency (EMEA) guidelines and demonstrated intra- and inter-assay precision with coefficients of variation ranging from 1.6 % to 6.1 % and accuracies between 90.2 % and 107.2 %. Stability testing, including autosampler, long-term and freeze-thaw stability, showed no more than 15 % variation. The method was successfully applied to 169 patient samples, revealing ocrelizumab concentrations ranging from 0.5 to 21.8 mg/L in patients on 6-month dosing regimen and 20.5-65.0 mg/L in 16 patients receiving an initial two-week dose of 300 mg. The newly developed UPLC-MS/MS method met all criteria for accuracy, precision and stability, confirming its suitability for clinical use in monitoring ocrelizumab levels in multiple sclerosis patients.
- MeSH
- chromatografie kapalinová metody MeSH
- humanizované monoklonální protilátky * terapeutické užití krev MeSH
- lidé MeSH
- monitorování léčiv metody MeSH
- roztroušená skleróza * farmakoterapie krev MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The aim of this study was to develop and validate methods for the determination of vitamins B2, B9, E and A in serum using liquid chromatography with mass spectrometry (MS) detection. Vitamin analysis was performed using an ultra performance liquid chromatography combined with tandem MS. The compounds were separated on a BEH C18 RP column (2.1 × 100 mm, 1.7 μm) using a gradient elution with an analysis time of 10 min. Sample preparation included protein precipitation with ethanol. The concentration range in human serum was as follows: riboflavin 5-1000 nmol/L, folic acid 2.5-250 nmol/L, α-tocopherol 0.5-100 μmol/L and all-trans-retinol 25-2500 nmol/L. Accuracy and precision were validated according to Food and Drug Administration guidelines, with coefficients of variation ranging from 3.1-11.7% and recoveries from 94.4-107.5%. Routine monitoring of the complex range of vitamins in bariatric medicine is still not common. This is despite the fact that patients are at risk for glitch deficits, especially of a neurological nature. An analytical method that allows for the complex measurement of both water-soluble and fat-soluble vitamins is important and necessary for the clinical monitoring of bariatric patients. The method we have described could benefit both clinical practice and nutritional research.
- MeSH
- alfa-tokoferol * krev MeSH
- bariatrická chirurgie MeSH
- chromatografie kapalinová metody MeSH
- kyselina listová * krev MeSH
- lidé MeSH
- limita detekce MeSH
- lineární modely MeSH
- reprodukovatelnost výsledků MeSH
- riboflavin * krev MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- vitamin A * krev MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
