Search results for "ADENOSINE"
showing 10 items of 542 documents
A Good Breath of Oxygen for Beta-Like Cells Obtained From Porcine Exocrine Pancreatic Tissue
2011
Ischemia is the most important factor that affects organ survival during harvesting. The two-layer method (TLM) is one of several cold storage solutions that seeks to preserve organs and cells avoiding in vivo and in vitro ischemia. We compared the retrieval of beta-like elements from exocrine pancreatic cells using TLM versus University of Wisconsin (UW) solutions. For this purpose pancreata laparoscopically harvested from 20 female pigs were preserved in UW solution or TLM before digestion. The resulting exocrine cells were divided into 2 groups: the first was cultured in a designed medium to allow differentiation into beta-like cells and the second was cryopreserved before the differenti…
Fluorescent Probes for Ecto-5′-nucleotidase (CD73)
2020
[Image: see text] Ecto-5′-nucleotidase (CD73) catalyzes the hydrolysis of AMP to anti-inflammatory, immunosuppressive adenosine. It is expressed on vascular endothelial, epithelial, and also numerous cancer cells where it strongly contributes to an immunosuppressive microenvironment. In the present study we designed and synthesized fluorescent-labeled CD73 inhibitors with low nanomolar affinity and high selectivity based on N(6)-benzyl-α,β-methylene-ADP (PSB-12379) as a lead structure. Fluorescein was attached to the benzyl residue via different linkers resulting in PSB-19416 (14b, K(i) 12.6 nM) and PSB-18332 (14a, K(i) 2.98 nM) as fluorescent high-affinity probes for CD73. These compounds …
Physiological and metabolic actions of mycophenolate mofetil on cultured newborn rat cardiomyocytes in normoxia and in simulated ischemia
2004
Mycophenolate mofetil (MMF) is a new immunosuppressive drug used to reduce acute rejection after heart transplantation. As with other immunosuppressive drugs, MMF therapy is associated with several adverse effects. However, the direct effects of MMF on myocardial tissue has not been yet evaluated. The aim of the work was thus to evaluate the effects of MMF on isolated cardiomyocytes (CM) in normal conditions and in an in vitro model of simulated ischemia (SI; substrate-free hypoxia) and reperfusion (R; reoxygenation). Myocyte-enriched cultures were prepared from newborn rat heart ventricles. The transmembrane potentials were recorded using conventional microelectrodes and the cell contracti…
Inorganic Polyphosphates As Storage for and Generator of Metabolic Energy in the Extracellular Matrix.
2019
Inorganic polyphosphates (polyP) consist of linear chains of orthophosphate residues, linked by high-energy phosphoanhydride bonds. They are evolutionarily old biopolymers that are present from bacteria to man. No other molecule concentrates as much (bio)chemically usable energy as polyP. However, the function and metabolism of this long-neglected polymer are scarcely known, especially in higher eukaryotes. In recent years, interest in polyP experienced a renaissance, beginning with the discovery of polyP as phosphate source in bone mineralization. Later, two discoveries placed polyP into the focus of regenerative medicine applications. First, polyP shows morphogenetic activity, i.e., induc…
In vitro model for DNA double‐strand break repair analysis in breast cancer reveals cell type–specific associations with age and prognosis
2016
Dysfunction of homologous recombination is a common denominator of changes associated with breast cancer-predisposing mutations. In our previous work, we identified a functional signature in peripheral blood lymphocytes from women who were predisposed that indicated a shift from homologous recombination to alternative, error-prone DNA double-strand break (DSB) repair pathways. To capture both hereditary and nonhereditary factors, we newly established a protocol for isolation and ex vivo analysis of epithelial cells, epithelial-mesenchymal transition cells (EMTs), and fibroblasts from breast cancer specimens (147 patients). By applying a fluorescence-based test system, we analyzed the error-…
Effects of muscular exercise on erythrocyte adenosine triphosphate concentration in patients with insulin-dependent diabetes mellitus.
1987
Type I diabetes mellitus represents a metabolic disorder in which intracellular glycolytic pathway is inhibited by insulin deficiency, with the subsequent decreased availability of energetic substrates such as ATP. Some aspects of the energetic metabolism in response to an intensive demand (muscular exercise) were investigated, in a group of 10 ketotic diabetic patients, by measuring erythrocyte adenosine triphosphate (ATP) and blood glucose, free fatty acids (FFA) and lactate levels. In the diabetic subjects, in comparison with normal subjects, the decreased levels of erythrocyte ATP at rest did not increase after exercise, while the increased levels of FFA at rest did not diminish after e…
Involvement of hydrogen and lipid peroxides in acute tobacco smoking-induced platelet hyperactivity
1995
Previous studies have established that cigarette smoking results in acute platelet hyperaggregability. We investigated whether changes in plasma oxidative properties could occur after smoking and whether such changes could be responsible for this enhanced platelet activity. In the present work, we report that platelets from nonsmokers become hyperactive after incubation with plasma prepared from blood of smokers obtained 10 min after smoking. This effect was not observed with presmoking plasma and could be inhibited in vitro by adding either catalase or reduced glutathione plus peroxidase to plasma or 2,6-di-tert-butyl-p-cresol (BHT) to platelets before incubation. Comparison of pre- and p…
Potential effects of age-associated oxidative stress on mammalian oocytes/embryos
1996
This bioessay aims to explain the different effects of maternal ageing and postovulatory oocyte ageing on mammalian oocytes/embryos under the scope of 'the oxygen radical-mitochondrial injury hypothesis of ageing'. This hypothesis assumes a key role in the senescent process of oxygen radical damage to mitochondrial DNA, proteins and lipids. It is proposed that a decrease in intracellular ATP concentrations and glutathione (GSH)/glutathione disulphide (GSSG) ratio together with a concomitant increase in cytosolic Ca2+ are major factors causing the observed detrimental effects of ageing on cytoskeletal fibres, fertilization and embryo development.
The Adverse Events and Hemodynamic Effects of Adenosine-Based Cardiac MRI
2011
OBJECTIVE We wanted to prospectively assess the adverse events and hemodynamic effects associated with an intravenous adenosine infusion in patients with suspected or known coronary artery disease and who were undergoing cardiac MRI. MATERIALS AND METHODS One hundred and sixty-eight patients (64 ± 9 years) received adenosine (140 µg/kg/min) during cardiac MRI. Before and during the administration, the heart rate, systemic blood pressure, and oxygen saturation were monitored using a MRI-compatible system. We documented any signs and symptoms of potential adverse events. RESULTS In total, 47 out of 168 patients (28%) experienced adverse effects, which were mostly mild or moderate. In 13 patie…
Prevention of ischemic-type biliary lesions by arterial back-table pressure perfusion
2003
Abstract Ischemic-type biliary lesions (ITBLs) lead to considerable morbidity after orthotopic liver transplantation (OLT). The exact pathogenesis is unknown. We tested the hypothesis that insufficient perfusion of biliary arterial vessels might be responsible for ITBLs. This could be prevented by improved perfusion techniques. Since February 2000, we performed a controlled study using arterial back-table pressure perfusion (AP) to achieve reliable perfusion of the biliary-tract capillary system, which may be impaired by the high viscosity of University of Wisconsin solution. We retrospectively analyzed 190 OLTs performed between September 1997 and July 2002 with regard to ITBLs. One hundre…