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    Wyświetlanie 1-3 z 3
    Tytuł:
    Chromatograficzna analiza związków budujących kwasy nukleinowe
    Chromatographic analysis of nucleic acids constituents
    Autorzy:
    Studzińska, S.
    Rola, R.
    Łobodziński, F.
    Krzemińska, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/172180.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    nukleozydy
    nukleotydy
    oligonukleotydy
    chromatografia cieczowa
    czułość
    selektywność
    nucleosides
    nucleotides
    oligonucleotides
    liquid chromatography
    sensitivity
    selectivity
    Opis:
    Understanding the characteristics, role and structure of nucleic acids allowed to answer questions about the disease processes. Today, nucleic acids and their constituents are tools, which are used by molecular biology in medicine and biotechnology. Antisense and gene therapy are intensively developing methods for possible treating or preventing disease. They use short fragments of DNA or RNA - oligonucleotides to silence the genes expression. They are not the only ones that allow analytical chemists to obtain information about the state of our body. Determination of modified nucleoside allows detection of cancer, while analysis of nucleotides allows the estimation of strengthening the immune system. There is a great need of sensitive, selective and precise methods of separation of nucleosides, nucleotides and oligonucleotides and their qualitative and quantitative analysis. Consequently liquid chromatography (LC) is the most commonly used for analysis of nucleic acid constituents. The most widely used modes of LC include Ion Exchange Chromatography (IEC) and Reversed Phase High Performance Liquid Chromatography (RP HPLC). Both techniques have their advantages and disadvantages in the analysis of nucleosides, nucleotides and oligonucleotides. In the case of IEC it is necessary to use high concentrations of the salt in the mobile phase or concentration gradients, which considerably limits the possibility of using MS detection. RP HPLC can be coupled with MS detection but only when volatile salts are mobile phase components. On the other hand there is a significant problem is the lack of sufficient selectivity for the most polar nucleosides and nucleotides. RP HPLC MS is still most often used in the determination of nucleosides and nucleotides, due to its high sensitivity and a comprehensive qualitative analysis. Another system used for the HPLC analysis of oligonucleotides is Ion Pair Reversed Phase High Performance Liquid Chromatography (IP RP HPLC). These compounds can not be analyzed by RP HPLC due to their high polarity. The advantage of IP RP HPLC is selectivity, achieved by a suitable choice of mobile phase composition and the possibility of using MS. A disadvantage of IP RP HPLC in the analysis of oligonucleotides is however lower sensitivity compared to RP HPLC. During the last few years Hydrophilic Interaction Liquid Chromatography (HILIC) was applied for the separation of mixtures of nucleosides, nucleotides, oligonucleotides extracted from a biological or food samples. The presented results demonstrate the usefulness of this method, however, the resolving power is limited due to the asymmetric peak shape. On the other hand proper selection of the mobile and stationary phase can lead to a high selectivity in the analysis of the most polar nucleosides, nucleotides and oligonucleotides, which can not be separated by RP HPLC.
    Źródło:
    Wiadomości Chemiczne; 2016, 70, 9-10; 633-656
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rola sygnalizacji purynergicznej i cytokin w indukcji procesów zapalnych w udarze niedokrwiennym mózgu
    Role of purinergic signalling and cytokines in the ischaemic stroke
    Autorzy:
    Cieślak, Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/1057753.pdf
    Data publikacji:
    2012
    Wydawca:
    Medical Communications
    Tematy:
    nukleotydy
    nukleozydy
    cytokiny
    receptory purynergiczne
    udar niedokrwienny mózgu
    nucleotides
    nucleosides
    cytokines
    purinergic receptors
    ischaemic stroke
    Opis:
    Inflammation plays an important role in the aetiology of various diseases of the central nervous system including the stroke. Accumulating evidence indicates that inflammation in the central nervous system is controlled by purinergic signalling. The mediators of purinergic signalling are extracellular nucleotides (e.g. ATP, ADP, UTP and UDP) and adenosine that act via activation of P2 and P1 purinergic receptors, respectively. The activation of P2 and P1 receptors is regulated by the enzymes ectonucleotidases that hydrolyse either extracellular nucleotides or adenosine. This review focuses on the role of purinergic signalling in the ischaemic stroke. We and others have demonstrated the presence of nucleotides and adenosine in the cerebrospinal fluid. We have also shown that the concentration of ATP and other nucleotides is increased in cerebrospinal fluid of patients with ischaemic stroke. Evidence suggests that the activation of P2 and P1 recep-tors have an opposite role in the ischaemic stroke, i.e. while the nucleoside adenosine exert neuroprotective effects, nucleotides generally promote the proinflammatory and apoptotic responses. P2X7, P2Y2, P2Y6, P2Y11 and P2Y12 are proposed to be involved in the central nervous system inflammation as they are expressed in the brain and their activation is known to control the key inflammatory processes such as release of inflammatory mediators (e.g. cytokines, NO), migration of leukocytes, phagocytosis, apoptosis and thrombosis. The activation of P2 receptors can also increase the release of excitatory neurotransmitters that further exacerbate the inflammatory response. Three cytokines whose release is controlled by P2 receptors have a major role in the ischaemic stroke, namely tumour necrosis factor alpha (TNF-α), interleukin 1 (IL-1) and interleukin 6 (IL-6). By promoting inflammation and thrombosis, these proinflammatory cytokines contribute to the increase in lesion size and thus functional impairment of the affected tissue. Cytokines as well as extracellular nucleotides are involved in leukocyte migration to lesions. By their adherence to endothelium, leukocytes impair cerebral blood circulation and thus exacerbate damage to the brain. The hydrolysis of nucleotides to adenosine by the ectonucleotidases leads to deactivation of proinflammatory responses. Similar effect can also be obtained with P2X7 and IL-1 receptor antagonists that are presently under clinical development and investigation.
    Wyniki badań opublikowanych w ostatnich latach wskazują, że indukcja stanów zapalnych w ośrodkowym układzie nerwowym może stanowić podstawę patofizjologiczną wielu chorób, w tym udaru niedokrwiennego mózgu. Istotną rolę w tych procesach przypisuje się sygnalizacji purynergicznej i cytokinom. Receptory purynergiczne P1 i P2 oraz enzymy uczestniczące w degradacji nukleotydów są szeroko rozpowszechnione na komórkach ośrodkowego układu nerwowego. Puryny i pirymidyny wykazują dwojakie działanie w udarze niedokrwiennym mózgu: pozytywne (neuroprotekcyjne) nukleozydów oraz negatywne (prozapalne i proapoptotyczne) nukleotydów. W przebiegu udaru niedokrwiennego mózgu udowodniono udział w indukcji procesów zapalnych trzech cytokin: czynnika martwicy nowotworów α (TNF-α), interleukiny 1 (IL-1) i interleukiny 6 (IL-6). Cytokiny prozapalne wywołują procesy zapalne i prozakrzepowe, przez co zwiększają obszar zawału, a w konsekwencji stopień deficytu neurologicznego. Cytokiny i ATP sprzyjają migracji leukocytów do miejsca niedokrwienia mózgu, natomiast adenozyna działa przeciwstawnie. Leukocyty, przylegając do śródbłonka, upośledzają przepływ mózgowy krwi, w wyniku czego nasilają uszkodzenie tkanki nerwowej. Na uwalnianie cytokin prozapalnych, głównie interleukiny 1β, wpływa aktywacja receptora P2X7. Przypuszcza się, że w procesach zapalnych ośrodkowego układu nerwowego mogą uczestniczyć także receptory: P2Y2, P2Y6, P2Y11, P2Y12. Wydaje się, że degradacja nukleotydów z powstaniem adenozyny może być skutecznym sposobem obniżenia stężenia w przestrzeni pozakomórkowej nukleotydów, jak również cytokin prozapalnych i wygaszania procesów zapalnych. Inną metodą osłabienia intensywności procesów zapalnych jest zastosowanie antagonistów receptora P2X7 oraz inhibitora receptora IL-1 (IL-1Ra). Obecnie prowadzone są badania zarówno nad potencjalnymi antagonistami receptora P2X7, jak i inhibitorem receptora IL-1 (IL-1Ra).
    Źródło:
    Aktualności Neurologiczne; 2012, 12, 4; 205-214
    1641-9227
    2451-0696
    Pojawia się w:
    Aktualności Neurologiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wykorzystanie spektrometrii mas do analizy modyfikacji nukleotydów i adduktów DNA
    Application of mass spectrometry methods for analysis of modified nucleotides and DNA adducts
    Autorzy:
    Hanus, J.
    Jelonek, K.
    Pietrowska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171867.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    kancerogeneza
    diagnostyka molekularna
    spektrometria mas
    nukleotydy
    uszkodzenia DNA
    addukty DNA
    metylacja DNA
    carcinogenesis
    molecular diagnostics
    mass spectrometry
    nucleotides
    DNA damage
    DNA adducts
    DNA methylation
    Opis:
    Chemically modified nucleotides, which are not normally present in genetic material, are called DN A adducts. This type of DN A modifications (damage) is directly related to processes of mutagenesis and carcinogenesis. Elevated levels of DN A adducts present in genetic material reflect exposure of humans to carcinogenic factors and are markers of increased risk of cancer [1]. For this reason different methods useful for quantitative and qualitative analyses of DN A adducts are used in the field of cancer prevention and research (Tab. 1). Enzymatically-catalyzed methylation of cytosine, observed mostly in so called CpG islands, is a frequent endogenous modification of genetic material. Such a DN A methylation is a key factor involved in regulation of gene expression, and methylation status of oncogenes and tumor supressor genes is an important biomarker of carcinogenesis. As such, analytical methods for assessment of DN A methylation are of great importance for molecular diagnostics of cancer. During the last decade significant progress has been made in methods available for quantitative, qualitative and structural analyses of biological molecules. Among intensively developed tools for bioanalyses are methods of mass spectrometry. Spectrometers that are based on two methods of ionization, namely electrospray ionization (ESI ) [30] and matrix-assisted laser desorption-ionization (MALDI ) [48], are particularly suitable for analyses of biological macromolecules: proteins and nucleic acids. Currently available mass spectrometers, together with microscale methods for sample preparation and separation, significantly increased sensitivity and accessible mass range of analyses. New generation of “user-friendly” instruments is developed to bring the techniques directly into the workplaces of biological and clinical investigators. This review demonstrates representative examples of mass spectrometry techniques used for qualitative analyses of nucleotide modifications and adducts present in genetic material of humans. In this field several methods base on spectrometers with electrospray ionization. Generated ions are separated according to their mass-to-charge ratio in an analyzer by electric fields; among different ion analyzers frequently used in this methods are single or triple quadrupole and ion traps (Fig. 1). Among other methods available for assessment of DN A adducts is so called Accelerator Mass Spectrometry (Fig. 2) [41]. The most frequently applied method for the assessment of DN A methylation is based on methylation-specific PCR reaction. Products of such PCR reactions are analyzed using MALDI mass spectrometry [54] (Fig. 3). In summary, new powerful methods of mass spectrometry that made available qualitative analyses of damage and modifications of human genetic material found their important place in modern biological and medical laboratories.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 3-4; 191-205
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-3 z 3

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