Browsing by Subject "Enzyme histochemistry"

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    Enzyme histochemistry: a useful tool for examining the spatial distribution of brain ectonucleotidases in (patho)physiological conditions
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2022) Grković, Ivana; Mitrović, Nataša; Dragić, Milorad; Kontić, Marina Zarić
    Adenosine 5'-triphosphate (ATP) and other nucleotides and nucleosides, such as adenosine, are versatile signaling molecules involved in many physiological processes and pathological conditions in the nervous system, especially those with an inflammatory component. They can be released from nerve cells, glial cells, and vascular cells into the extracellular space where they exert their function via ionotropic (P2X) or metabotropic (P2Y) receptors. Signaling via extracellular nucleotides and adenosine is regulated by cell-surface located enzymes ectonucleotidases that hydrolyze the nucleotide to the respective nucleoside. This review summarizes a histochemical approach for detection of ectonucleotidase activities in the cryo-sections of brain tissue. The enzyme histochemistry (EHC) might be used as suitable replacement for immunohistochemistry, since it gives information about both localization and activity, thus adding a functional component to a classical histological approach. With this technique, it is possible to visualize spatial distribution and cell-specific localization of ectonucleoside triphosphate diphosphohydrolases (NTPDases) and ecto-5'-nucleotidase (eN/CD73) activities during brain development, after different hormonal manipulations, during neurodegeneration, etc. EHC is also suitable for investigation of microglial morphology in different (patho)physiological conditions. Furthermore, the review describes how to quantify EHC results.
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    Salivary gland carbonic anhydrases
    (Servicio de Publicaciones, Departamento de Histología e Histopatología, 2025) Redman Robert S.; Biología Celular e Histología
    Carbonic anhydrases (CA) are zinc metalloenzymes that catalyze the reversible conversion of carbon dioxide and water to bicarbonate. For most mammalian cells, this reaction is essential to maintaining intracellular physiological pH. For salivary glands, it also has an important role in the regulation of the pH and buffering capacity of their secretory product, saliva, which is central to the activity of salivary digestive enzymes. This review is a chronological narrative of the discovery and distribution of CA and its isoenzymes in mammalian salivary glands and saliva and the role of CA in regulation of salivary pH via secretion of the salivary CA isoenzyme and the secretion and reabsorption of bicarbonate from the ductal lumen. The interaction of sodium/bicarbonate co-transporters and other factors in these processes is briefly described. The distribution of CA among mammalian species, salivary glands, and gland cells as determined by CA activity in saliva and gland extracts, enzyme histochemistry, and immunohistochemistry is presented in tables. The importance of salivary CA to oral health is underscored by the reduction in salivary gland and salivary CA activity by nutritional zinc deficiency and genetic variants of two of the CA isoenzymes, which cause dysgeusia and hyposalivation and are associated with increased dental caries
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    The role of xanthine oxidase in
    (Murcia : F. Hernández, 1995) Frederiks, W.M.; Bosch, K.S.
    Oxygen radicals have been proposed to be involved in the induction of liver cell damage during reperfusion after ischemia. The role of xanthine oxidase in this process and the potential of the antioxidant system have been studied in a model of in vivo ischemia of rat liver followed by 1 h reperfusion by the use of enzyme histochemistry. Based on decreased lactate dehydrogenase activity in certain areas of liver parenchyma, cell damage could already be detected at 1 h reperfusion after ischemia. Incubations performed on serial sections showed that the same areas contained decreased activities of xanthine oxidoreductase, xanthine oxidase, catalase and glucose-6-phosphate dehydrogenase. Some individual cells in the undamaged liver parenchyma expressed a very high glucose-6-phosphate dehydrogenase, which suggests that these cells have a good defence against oxidative stress. It is concluded that oxygen radicals derived from xanthine oxidase do not play a decisive role in the induction of cell damage immediately at reperfusion after ischemia. However, it cannot be excluded that xanthine oxidase present in the blood stream can give rise to the development of additional damage later on.