Browsing by Subject "TANDEM MASS-SPECTROMETRY"

Sort by: Order: Results:

Now showing items 1-20 of 21
  • Avela, Henri F.; Siren, Heli (2020)
    The present article examines recently published literature on lipids, mainly focusing on research involving glycero-, glycerophospho- and sphingo-lipids. The primary aim is identification of distinct profiles in biologic lipidomic systems by ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry (MS, tandem MS) with multivariate data analysis. This review specifically targets lipid biomarkers and disease pathway mechanisms in humans and artificial targets. Different specimen matrices such as primary blood derivatives (plasma, serum, erythrocytes, and blood platelets), faecal matter, urine, as well as biologic tissues (liver, lung and kidney) are highlighted.
  • Timperley, Christopher M.; Forman, Jonathan E.; Abdollahi, Mohammad; Al-Amri, Abdullah Saeed; Alonso, Isel Pascual; Baulig, Augustin; Borrett, Veronica; Cariño, Flerida A.; Curty, Christophe; Berrutti, David González; Kovarik, Zrinka; Martínez-Álvarez, Roberto; Mikulak, Robert; Mourão, Nicia Maria Fusaro; Ponnadurai, Ramasami; Neffe, Slawomir; Raza, Syed K.; Rubaylo, Valentin; Takeuchi, Koji; Tang, Cheng; Trifirò, Ferruccio; Mauritz van Straten, Francois; Vanninen, Paula S.; Zaitsev, Volodymyr; Waqar, Farhat; Zina, Mongia Saïd; Blum, Marc-Michael; Gregg, Hugh; Fischer, Elena; Sun, Siqing; Yang, Pei (2018)
    Abstract The Scientific Advisory Board (SAB) of the Organisation for the Prohibition of Chemical Weapons (OPCW) has provided advice on the long-term storage and stability of samples collected in the context of chemical weapons investigations. The information they compiled and reviewed is beneficial to all laboratories that carry out analysis of samples related to chemical warfare agents and is described herein. The preparation of this report was undertaken on request from the OPCW Director-General. The main degradation products for chemicals on the Schedules in the Annex on Chemicals of the Chemical Weapons Convention are tabulated. The expertise of the 25 scientists comprising the SAB, a review of the scientific literature on environmental and biomedical sample analysis, and answers to a questionnaire from chemists of nine OPCW Designated Laboratories, were drawn upon to provide the advice. Ten recommendations to ensure the long-term storage and stability of samples collected in relation to the potential use of chemical weapons were provided and are repeated here for the consideration of all laboratories worldwide.
  • Kilpinen, Lotta; Tigistu-Sahle, Feven; Oja, Sofia; Greco, Dario; Parmar, Amarjit; Saavalainen, Päivi Marjaana; Nikkilä, Janne Tapio; Korhonen, Matti; Lehenkari, Petri; Käkelä, Reijo; Laitinen, Saara (2013)
  • Mysore, Raghavendra; Liebisch, Gerhard; Zhou, You; Olkkonen, Vesa M.; Haridas, P. A. Nidhina (2017)
    Angiopoietin-like 8 (Angptl8) inhibits lipolysis in the circulation together with Angplt3 and controls post-prandial fat storage in white adipose tissue (WAT). It is strongly induced by insulin in vivo in WAT and in vitro in adipocytes. In this study we addressed the function of Angptl8 in adipocytes by its stable lentivirus-mediated knock-down in 3T3-L1 cells, followed by analyses of triglyceride (TG) storage, lipid droplet (LD) morphology, the cellular lipidome, lipolysis, and gene expression. Depletion of Angptl8 did not drastically affect the adipocyte differentiation of 3T3-L1 cells but resulted in a moderate (18-19%) reduction of stored TGs. The lipidome analysis revealed a reduction of alkyl-phosphatidylcholines (PCs) and phosphatidylethanolamine (PE) plasmalogens, as well as saturated PCs and PEs. Importantly, the Angptl8 depleted cells displayed enhanced lipolysis as measured by release of non-esterified fatty acids (NEFA5). Consistently, mRNAs encoding Angptl4 and Leptin, which facilitate lipolysis, as well as Cpt1a, Cpt1b, and Pgc-1 alpha involved in FA oxidation, were elevated. The Angptl8 mRNA itself was suppressed by pharmacologic treatments inducing lipolysis: stimulation with the beta-adrenergic agonist isoproterenol or with the adenylate cyclase activator forskolin. To conclude, knock-down of Angptl8 in adipocytes suggests that the protein acts to inhibit intracellular lipolysis, analogous to its activity in the circulation. Depletion of Angptl8 results in an altered cellular phospholipid composition. The findings identify Angptl8 as a central insulin-regulated controller of adipocyte lipid metabolism. (C) 2017 Elsevier B.V. All rights reserved.
  • Julkunen-Tiitto, Riitta; Nenadis, Nikolaos; Neugart, Susanne; Robson, Matthew; Agati, Giovanni; Vepsalainen, Jouko; Zipoli, Gaetano; Nybakken, Line; Winkler, Barbro; Jansen, Marcel A. K. (2015)
    Flavonoids are a large group of plant secondary metabolites that are present in most plants, and are vital for plant growth, development and protection. Among the many functions of these compounds is their contribution to stress amelioration. The accurate identification and quantification of total or individual flavonoids in plants exposed to stressful conditions (e.g. ultraviolet radiation) is challenging due to their structural diversity. The present review provides the up to date knowledge and highlights trends in plant flavonoid analysis. The review covers all steps from the field to the laboratory, focussing on UV-B effects on flavonoids, and identifying critical issues concerning sample collection, pre-treatment, extraction techniques and quantitative or qualitative analysis. A well-planned sampling and sample prehandling strategy is vital when capturing organ, tissue and developmental-stage dependent changes in flavonoids, as well as the dynamic changes due to time of UV-exposure and diurnal or seasonal parameters. A range of advanced extraction and purification techniques can facilitate the quantitative transfer of flavonoids to solvents. The advantages and disadvantages of analytical methods, including chromogenic assays, liquid and thin-layer chromatography, mass spectrometry, nuclear magnetic resonance detection, and non-destructive in situ fluorescent analysis need to be consciously evaluated in the context of the specific biological question posed. Thus, no one method can be applied to every single study of flavonoid. The message of this review is that researchers will need to carefully consider the biological process that they intend to study, and select an analytical method that optimally matches their specific objectives.
  • Saraswat, Mayank; Joenvaara, Sakari; Seppanen, Hanna; Mustonen, Harri; Haglund, Caj; Renkonen, Risto (2017)
    Finland ranks sixth among the countries having highest incidence rate of pancreatic cancer with mortality roughly equaling incidence. The average age of diagnosis for pancreatic cancer is 69years in Nordic males, whereas the average age of diagnosis of chronic pancreatitis is 40-50years, however, many cases overlap in age. By radiology, the evaluation of a pancreatic mass, that is, the differential diagnosis between chronic pancreatitis and pancreatic cancer is often difficult. Preoperative needle biopsies are difficult to obtain and are demanding to interpret. New blood based biomarkers are needed. The accuracy of the only established biomarker for pancreatic cancer, CA 19-9 is rather poor in differentiating between benign and malignant mass of the pancreas. In this study, we have performed mass spectrometry analysis (High Definition MSE) of serum samples from patients with chronic pancreatitis (13) and pancreatic cancer (22). We have quantified 291 proteins and performed detailed statistical analysis such as principal component analysis, orthogonal partial least square discriminant analysis and receiver operating curve analysis. The proteomic signature of chronic pancreatitis versus pancreatic cancer samples was able to separate the two groups by multiple statistical techniques. Some of the enriched pathways in the proteomic dataset were LXR/RXR activation, complement and coagulation systems and inflammatory response. We propose that multiple high-confidence biomarker candidates in our pilot study including Inter-alpha-trypsin inhibitor heavy chain H2 (Area under the curve, AUC: 0.947), protein AMBP (AUC: 0.951) and prothrombin (AUC: 0.917), which should be further evaluated in larger patient series as potential new biomarkers for differential diagnosis.
  • Lindström, Mikael; Tohmola, Niina; Renkonen, Risto; Hämäläinen, Esa; Schalin-Jäntti, Camilla; Itkonen, Outi (2018)
    Background: Serotonin (5-hydroxytyramine) is a mediator of gastrointestinal smooth muscle contraction, and is secreted by neuroendocrine neoplasms (NENs). We developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for serum serotonin to be used in NEN diagnostics and follow-up. Methods: We used serum samples from healthy volunteers (n = 31) and patients suspected or monitored for NEN (n = 98). Serotonin-D-4 internal standard was added to samples before solid phase extraction (SPE) and quantification by LC-MS/MS. The effects of sample handling and preparation on serotonin stability were studied. Finally, we established a provisional reference range for serum serotonin and compared our assay with serum 5hydroxyindoleacetic acid (5-HIAA) for detection of NENs. Results: Our assay is sensitive and has a wide linear range (10-10,000 nmo1/1). Serum serotonin is stable for 7 days at room temperature and for 3 months at -20 degrees C. Sampling temperature is not critical. Normal range for serum serotonin was 270-1490 nmo1/1. We found that serum serotonin and 5-HIAA performed equally well as diagnostic tests for NENs. Conclusions: Our LC-MS/MS assay for serum serotonin is well suited for clinical research and patient diagnostics. Our results confirm that it can complement 5-HIAA in diagnosis of NENs.
  • Yetukuri, Laxman; Soderlund, Sanni; Koivuniemi, Artturi; Seppanen-Laakso, Tuulikki; Niemela, Perttu S.; Hyvonen, Marja; Taskinen, Marja-Riitta; Vattulainen, Ilpo Tapio; Jauhiainen, Matti; Oresic, Matej (2010)
  • Suominen, Tina; Uutela, Paivi; Ketola, Raimo A.; Bergquist, Jonas; Hillered, Lars; Finel, Moshe; Zhang, Hongbo; Laakso, Aki; Kostiainen, Risto (2013)
    An UPLC-MS/MS method was developed for the determination of serotonin (5-HT), dopamine (DA), their phase I metabolites 5-HIAA, DOPAC and HVA, and their sulfate and glucuronide conjugates in human brain microdialysis samples obtained from two patients with acute brain injuries, ventricular cerebrospinal fluid (CSF) samples obtained from four patients with obstructive hydrocephalus, and a lumbar CSF sample pooled mainly from patients undergoing spinal anesthesia in preparation for orthopedic surgery. The method was validated by determining the limits of detection and quantification, linearity, repeatability and specificity. The direct method enabled the analysis of the intact phase II metabolites of 5-HT and DA, without hydrolysis of the conjugates. The method also enabled the analysis of the regioisomers of the conjugates, and several intact glucuronide and sulfate conjugates were identified and quantified for the first time in the human brain microdialysis and CSF samples. We were able to show the presence of 5-HIAA sulfate, and that dopamine-3-O-sulfate predominates over dopamine-4-O-sulfate in the human brain. The quantitative results suggest that sulfonation is a more important phase II metabolism pathway than glucuronidation in the human brain.
  • Kauhanen, Dimple; Sysi-Aho, Marko; Koistinen, Kaisa M.; Laaksonen, Reijo; Sinisalo, Juha; Ekroos, Kim (2016)
    Monitoring the levels of the ceramides (Cer) d18:1/16:0, Cer d18:1/18:0, Cer d18:1/24:0, and Cer d18:1/24:1 and ratios thereof in human plasma empowers the prediction of fatal outcome of coronary artery disease (CAD). We describe a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology for clinical-scaled measurement of the four distinct ceramides. Rapid plasma precipitation was accomplished in 96-well format. Excellent extraction recoveries in the range of 98-109 % were achieved for each ceramide. Addition of corresponding D-7-labeled ceramide standards facilitated precise quantification of each plasma ceramide species utilizing a novel short 5-min LC-MS/MS method. Neither matrix interference nor carryover was observed. Robust intra- and inter-assay accuracy and precision <15 % at five different concentrations were obtained. Linear calibration lines with regressions, R (2) > 0.99, were achieved for all analytes. Short-term bench top, long-term plasma, and extract stability demonstrated that the distinct ceramides were stable in the conditions evaluated. The validity of the methodology was demonstrated by determining the precise ceramide concentrations in a small CAD case-control study. Thus, our LC-MS/MS methodology features simple sample preparation and short analysis time for accurate quantification of Cer d18:1/16:0, Cer d18:1/18:0, Cer d18:1/24:0, and Cer d18:1/24:1, designed for routine analysis.
  • Jonsson, Martina; Jestoi, Marika; Anthoni, Minna; Welling, Annikki; Loivamaa, Iida; Hallikainen, Ville; Kankainen, Matti; Lysoe, Erik; Koivisto, Pertti; Peltonen, Kimmo (2016)
    The mycotoxin enniatin B, a cyclic hexadepsipeptide produced by the plant pathogen Fusarium, is prevalent in grains and grain-based products in different geographical areas. Although enniatins have not been associated with toxic outbreaks, they have caused toxicity in vitro in several cell lines. In this study, the cytotoxic effects of enniatin B were assessed in relation to cellular energy metabolism, cell proliferation, and the induction of apoptosis in Balb 3T3 and HepG2 cells. The mechanism of toxicity was examined by means of whole genome expression profiling of exposed rat primary hepatocytes. Enniatin B altered cellular energy metabolism and reduced cell proliferation in Balb 3T3 and HepG2 cell lines. Furthermore, the proportion of apoptotic cell populations of Balb 3T3 cells slightly increased. On the other hand, enniatin B caused necrotic cell death in primary hepatocytes. Gene expression studies revealed the alteration of energy metabolism due to effects on mitochondrial organization and function and the assembly of complex I of the electron transport chain. (C) 2016 Elsevier Ltd. All rights reserved.
  • Nagaraj, Meghana; Höring, Marcus; Ahonen, Maria A.; Van Dien Nguyen; Zhou, You; Vihinen, Helena; Jokitalo, Eija; Liebisch, Gerhard; Haridas, P. A. Nidhina; Olkkonen, Vesa M. (2022)
    Golgi membrane protein 1 (GOLM1) is a Golgi-resident type 2 transmembrane protein known to be overexpressed in several cancers, including he-patocellular carcinoma (HCC), as well as in viral in-fections. However, the role of GOLM1 in lipid metabolism remains enigmatic. In this study, we employed siRNA-mediated GOLM1 depletion in Huh -7 HCC cells to study the role of GOLM1 in lipid metabolism. Mass spectrometric lipidomic analysis in GOLM1 knockdown cells showed an aberrant accu-mulation of sphingolipids, such as ceramides, hex-osylceramides, dihexosylceramides, sphinganine, sphingosine, and ceramide phosphate, along with cholesteryl esters. Furthermore, we observed a reduction in phosphatidylethanolamines and lyso-phosphatidylethanolamines. In addition, Seahorse extracellular flux analysis indicated a reduction in mitochondrial oxygen consumption rate upon GOLM1 depletion. Finally, alterations in Golgi struc-ture and distribution were observed both by electron microscopy imaging and immunofluorescence mi-croscopy analysis. Importantly, we found that GOLM1 depletion also affected cell proliferation and cell cycle progression in Huh-7 HCC cells. The Golgi structural defects induced by GOLM1 reduction might potentially affect the trafficking of proteins and lipids leading to distorted intracellular lipid ho-meostasis, which may result in organelle dysfunction and altered cell growth. In conclusion, we demon-strate that GOLM1 depletion affects sphingolipid metabolism, mitochondrial function, Golgi structure, and proliferation of HCC cells.
  • Moravcova, Dana; Planeta, Josef; King, Alistair William Thomas; Wiedmer, Susanne Kristina (2018)
    A methodology for preparing phosphonium-based ionic liquid modified silica-based monolithic capillary columns is presented. The silica monolithic columns with dimensions of 150 × 0.1 mm were modified by a phosphonium-based ionic liquid (trioctyl(3/4-vinylbenzyl)phosphonium chloride) via3-(trimethoxysilyl)propyl methacrylate. The prepared columns were evaluated under hydrophilic inter-action liquid chromatography separation conditions, employing a sample mixture containing purine and pyrimidine bases and nucleosides. Detection was made by UV. The high efficiency of the original silica monolith was preserved even after modification, and it reached values in the range of 98,000–174,000 theoretical plates/m. The effects of the concentration of acetonitrile in the mobile phase, the presence of additives in the mobile phase, such as, acetic acid or ammonium acetate, and the pH of the mobile phaseon the separation of some selected analytes were investigated. The prepared columns showed different separation selectivity compared to silica, phenyl and sulfobetaine stationary phases.
  • Ahonen, Maria A.; Höring, Marcus; Nguyen, Van Dien; Qadri, Sami; Taskinen, Juuso H.; Nagaraj, Meghana; Wabitsch, Martin; Fischer-Posovszky, Pamela; Zhou, You; Liebisch, Gerhard; Haridas, P. A. Nidhina; Yki-Järvinen, Hannele; Olkkonen, Vesa M. (2022)
    Background Thyroid hormone responsive protein (THRSP) is a lipogenic nuclear protein that is highly expressed in murine adipose tissue, but its role in humans remains unknown. Methods We characterized the insulin regulation of THRSP in vivo in human adipose tissue biopsies and in vitro in Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. To this end, we measured whole-body insulin sensitivity using the euglycemic insulin clamp technique in 36 subjects [age 40 +/- 9 years, body mass index (BMI) 27.3 +/- 5.0 kg/m(2)]. Adipose tissue biopsies were obtained at baseline and after 180 and 360 min of euglycemic hyperinsulinemia for measurement of THRSP mRNA concentrations. To identify functions affected by THRSP, we performed a transcriptomic analysis of THRSP-silenced SGBS adipocytes. Mitochondrial function was assessed by measuring mitochondrial respiration as well as oxidation and uptake of radiolabeled oleate and glucose. Lipid composition in THRSP silencing was studied by lipidomic analysis. Results We found insulin to increase THRSP mRNA expression 5- and 8-fold after 180 and 360 min of in vivo euglycemic hyperinsulinemia. This induction was impaired in insulin-resistant subjects, and THRSP expression was closely correlated with whole-body insulin sensitivity. In vitro, insulin increased both THRSP mRNA and protein concentrations in SGBS adipocytes in a phosphoinositide 3-kinase (PI3K)-dependent manner. A transcriptomic analysis of THRSP-silenced adipocytes showed alterations in mitochondrial functions and pathways of lipid metabolism, which were corroborated by significantly impaired mitochondrial respiration and fatty acid oxidation. A lipidomic analysis revealed decreased hexosylceramide concentrations, supported by the transcript concentrations of enzymes regulating sphingolipid metabolism. Conclusions THRSP is regulated by insulin both in vivo in human adipose tissue and in vitro in adipocytes, and its expression is downregulated by insulin resistance. As THRSP silencing decreases mitochondrial respiration and fatty acid oxidation, its downregulation in human adipose tissue could contribute to mitochondrial dysfunction. Furthermore, disturbed sphingolipid metabolism could add to metabolic dysfunction in obese adipose tissue.
  • Tienaho, Jenni; Karonen, Maarit; Muilu-Mäkelä, Riina; Wähälä, Kristiina; Leon Denegri, Eduardo; Franzén, Robert; Karp, Matti; Santala, Ville; Sarjala, Tytti (2019)
    Endophytes are microorganisms living inside plant hosts and are known to be beneficial for the host plant vitality. In this study, we isolated three endophytic fungus species from the roots of Scots pine seedlings growing on Finnish drained peatland setting. The isolated fungi belonged to dark septate endophytes (DSE). The metabolic profiles of the hot water extracts of the fungi were investigated using Ultrahigh Performance Liquid Chromatography with Diode Array Detection and Electron Spray Ionization source Mass Spectrometry with Orbitrap analyzer (UPLC–DAD–ESI–MS–Orbitrap). Out of 318 metabolites, we were able to identify 220, of which a majority was amino acids and peptides. Additionally, opine amino acids, amino acid quinones, Amadori compounds, cholines, nucleobases, nucleosides, nucleotides, siderophores, sugars, sugar alcohols and disaccharides were found, as well as other previously reported metabolites from plants or endophytes. Some dierences of the metabolic profiles, regarding the amount and identity of the found metabolites, were observed even though the fungi were isolated from the same host. Many of the discovered metabolites have been described possessing biological activities and properties, which may make a favorable contribution to the host plant nutrient availability or abiotic and biotic stress tolerance.
  • Tigistu-Sahle, Feven; Lampinen, Milla; Kilpinen, Lotta; Holopainen, Minna; Lehenkari, Petri; Laitinen, Saara; Käkelä, Reijo (2017)
    High arachidonic acid (20:4n-6) and low n-3 PUFA levels impair the capacity of cultured human bone marrow mesenchymal stromal cells (hBMSCs) to modulate immune functions. The capacity of the hBMSCs to modify PUFA structures was found to be limited. Therefore, different PUFA supplements given to the cells resulted in very different glycerophospholipid (GPL) species profiles and substrate availability for phospholipases, which have preferences for polar head group and acyl chains when liberating PUFA precursors for production of lipid mediators. When supplemented with 20:4n-6, the cells increased prostaglandin E2 secretion. However, they elongated 20:4n-6 to the less active precursor, 22:4n-6, and also incorporated it into triacylglycerols, which may have limited the proinflammatory signaling. The n-3 PUFA precursor, 18:3n-3, had little potency to reduce the GPL 20:4n-6 content, while the eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acid supplements efficiently displaced the 20:4n-6 acyls, and created diverse GPL species substrate pools allowing attenuation of inflammatory signaling.(Jlr) The results emphasize the importance of choosing appropriate PUFA supplements for in vitro hBMSC expansion and suggests that for optimal function they require an exogenous fatty acid source providing 20:5n-3 and 22:6n-3 sufficiently, but 20:4n-6 moderately, which calls for specifically designed optimal PUFA supplements for the cultures.
  • Vihma, Veera; Naukkarinen, Jussi; Turpeinen, Ursula; Hämäläinen, Esa; Kaprio, Jaakko; Rissanen, Aila; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S.; Tikkanen, Matti J.; Pietiläinen, Kirsi H. (2017)
    Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n = 18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36 kg/m(2)] included 9 male MZ twin pairs discordant for BMI [infra-pair difference (Delta) in BMI >= 3 kg/m(2)]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean Delta BMI = 5.9 kg/m2), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P = 0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P = 0.021) and cortisol-producing HSD11B1 (P = 0.008) higher in the heavier compared to the leaner co-twins. Serum free 17 beta-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P = 0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P = 0.006; and 123 (43) vs. 105 (27) pmol/l, P = 0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (P <0.01 for all), 2) infra-abdominal fat with total testosterone and SHBG (P <0.05), and 3) liver fat with SHBG (P = 0.006). Also, 4) general and intra-abdominal adiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (P <0.05). In conclusion, acquired adiposity was associated with decreased serum DHT and increased estrogen concentrations, independent of genetic factors and age. The reduction of DHT could be linked to its increased degradation (by AKR1C2 and HSD11B1) and increased estrogen levels to increased adiposity-related expression of aromatase in adipose tissue.
  • Suominen, Tina; Piepponen, T. Petteri; Kostiainen, Risto (2015)
    Dopamine sulfate (DA-3- and DA-4-S) have been determined in the human brain, but it is unclear whether they are locally formed in the central nervous system (CNS), or transported into the CNS from peripheral sources. In the current study, permeation of the blood-brain barrier (BBB) by DA-S was studied by injecting C-13(6)-labelled regioisomers of DA-S ((13)DA-3-S and (13)DA-4-S) and dopamine (DA) subcutaneously (s.c.) in anesthetized rats, then analyzing brain microdialysis and plasma samples by UPLC-MS/MS. The results in the microdialysis samples demonstrated that brain concentrations of (13)DA-S regioisomers clearly increased after the s.c. injections. The concentration of DA did not change, indicating the permeation of DA-S through an intact BBB. The analysis of plasma samples, however, showed that DA-S only permeates the BBB to a small extent, as the concentrations in plasma were substantially higher than in the microdialysis samples. The results also showed that the concentrations of DA-3-S were around three times higher than the concentrations of DA-4-S in rat brain, as well as in the plasma samples after the s.c. injections, indicating that DA-3-S and DA-4-S permeate the BBB with similar efficiency. The fate of (13)DA-S in brain was followed by monitoring C-13(6)-labelled DA-S hydrolysis products, i.e. (13)DA and its common metabolites; however, no C-13(6)-labelled products were detected. This suggests that DA-S either permeates through the BBB back to the peripheral circulation or is dissociated or metabolized by unexpected mechanisms.
  • Kirwan, Jennifer A.; Brennan, Lorraine; Broadhurst, David; Fiehn, Oliver; Cascante, Marta; Dunn, Warwick B.; Schmidt, Michael A.; Velagapudi, Vidya (2018)
    BACKGROUND: The metabolome of any given biological system contains a diverse range of low molecular weight molecules (metabolites), whose abundances can be affected by the timing and method of sample collection, storage, and handling. Thus, it is necessary to consider the requirements for preanalytical processes and biobanking in metabolomics research. Poor practice can create bias and have deleterious effects on the robustness and reproducibility of acquired data. CONTENT: This review presents both current practice and latest evidence on preanalytical processes and biobanking of samples intended for metabolomics measurement of common biofluids and tissues. It highlights areas requiring more validation and research and provides some evidence-based guidelines on best practices. SUMMARY: Although many researchers and biobanking personnel are familiar with the necessity of standardizing sample collection procedures at the axiomatic level (e.g., fasting status, time of day, "time to freezer," sample volume), other less obvious factors can also negatively affect the validity of a study, such as vial size, material and batch, centrifuge speeds, storage temperature, time and conditions, and even environmental changes in the collection room. Any biobank or research study should establish and follow a well-defined and validated protocol for the collection of samples for metabolomics research. This protocol should be fully documented in any resulting study and should involve all stakeholders in its design. The use of samples that have been collected using standardized and validated protocols is a prerequisite to enable robust biological interpretation unhindered by unnecessary preanalytical factors that may complicate data analysis and interpretation. (C) 2018 American Association for Clinical Chemistry
  • Adebayo, Folasade; Itkonen, Suvi; Öhman, Taina; Kiely, Mairead E; Cashman, Kevin; Lamberg-Allardt, Christel (2021)
    The safety considerations of food-based solutions for vitamin D deficiency prevention, such as fortification and supplementation, are critical. On the basis of collective data from 20 randomized controlled trials (RCTs) and 20 national healthy surveys, as well as prospective cohort studies (PCSs) across the ODIN project (“Food-based solutions for optimal vitamin D nutrition and health through the life cycle”, FP7-613977), we analyzed the potential safety issues arising from vitamin D intakes and/or supplementation. These adverse consequences included high serum 25-hydroxyvitamin D (S-25(OH)D) concentrations (>125 nmol/L), high serum calcium concentrations, and vitamin D intakes in excess of the tolerable upper intake levels (ULs). In the RCTs (n = 3353, with vitamin D doses from 5–175 µg/day), there were no reported adverse effects. The prevalence of high S-25(OH)D was <10% when vitamin D supplements were administered, and <0.1% for fortified foods. Elevated serum calcium was observed among <0.5% in both administration types. No ODIN RCT participants exceeded the age-specific ULs. In observational studies (n = 61,082), the prevalence of high 25(OH)D among children/adolescents, adults, and older adults was <0.3%, with no evidence of adverse effects. In conclusion, high S-25(OH)D concentrations >125 nmol/L were rare in the RCTs and PCSs, and no associated adverse effects were observed.