The concentration-dependence of tert-butyl hydroperoxide (BHP) inhibitory effect on oxygen consumption in isolated rat liver mitochondria was measured in the presence of various respiratory substrates. Strong inhibitory effect at low concentrations of BHP (15-30 μM) was found for oxoglutarate and palmitoyl carnitine oxidation. Pyruvate and glutamate oxidation was inhibited at higher concentrations of BHP (100-200 μM). Succinate oxidation was not affected even at 3.3 mM BHP. Determination of mitochondrial membrane potential has shown that in the presence of NADH-dependent substrates the membrane potential was dissipated by BHP but was completely restored after addition of succinate. Our data thus indicate that beside peroxidative damage of complex I also various mitochondrial NADH-dependent dehydrogenases are inhibited, but to a different extent and with different kinetics. Our data also show that succinate could be an important nutritional substrate protecting hepatocytes during peroxidative damage., R. Endlicher ... [et al.]., and Obsahuje seznam literatury
In as early as 1997, the World Health Organization officially recognized obesity as a chronic disease. The current epidemic of obesity and overweightness has aroused great interest in the study of adipose tissue formation. The transcription factor peroxisome proliferator-activated receptor γ (PPARγ) binds to the target gene promoter regulatory sequences, acting as a key factor in regulating the differentiation of preadipocytes in the adipose tissue, and plays an important role in regulating the adipocyte metabolism. A further understanding of the structure and expression characteristics of PPARγ, in addition to its mechanisms of action in adipocyte differentiation, may be applied to control obesity and prevent obesity-related diseases. In this article, recent studies investigating the effect of regulating PPARγ on adipocyte differentiation are reviewed. In particular, the structural characteristics, expression patterns, and molecular mechanisms of PPARγ function in adipocyte differentiation are considered., Hui Wu, Xiaohua Li, Chunyan Shen., and Obsahuje bibliografii
Six genotypes of taro (Colocasia esculenta L. Schott) were evaluated under in vitro and in vivo polyethylene glycol (PEG-6000)-mediated osmotic stress conditions. A significant variation in growth response was observed among the taro genotypes under in vitro-induced stress conditions. In vivo results indicated a significant effect of osmotic stress on photosynthetic parameters, such as net photosynthetic rate, transpiration rate, stomatal conductance, stomatal resistance, internal CO2 concentration, carboxylation efficiency, and transpiration efficiency on the tested genotypes at the tuberization stage. Lesser variations in photosynthesis and higher accumulation of proline, phenols, and antioxidative enzymes, namely, superoxide dismutase and guaiacol peroxidase, were associated with yield maintenance under osmotic stress conditions. The genotypes DP-89, IGCOL-4, and Ramhipur showed a higher degree of tolerance towards osmotic stress with a minimum variation in the studied parameters. These genotypes could be lines of interest for intensification of breeding strategies to develop drought-tolerant plants., M. R. Sahoo, M. Dasgupta, P. C. Kole, A. Mukherjee., and Obsahuje bibliografii
Fibroblast growth factor (FGF) signaling plays an important role during embryonic induction and patterning, as well as in modulating proliferative and hypertrophic growth in fetal and adult organs. Hemodynamically induced stretching is a powerful physiological stimulus for embryonic myocyte proliferation. The aim of this study was to assess the effect of FGF2 signaling on growth and vascularization of chick embryonic ventricular wall and its involvement in transmission of mechanical stretchinduced signaling to myocyte growth in vivo . Myocyte proliferation was significantly higher at the 48 h sampling interval in pressure-overloaded hearts. Neither Western blotting, nor immunohistochemistry performed on serial paraffin sections revealed any changes in the amount of myocardial FGF2 at that time point. ELISA showed a significant increase of FGF2 in the serum. Increased amount of FGF2 mRNA in the heart was confirmed by real time PCR. Blocking of FGF signaling by SU5402 led to decreased myocyte proliferation, hemorrhages in the areas of developing vasculature in epicardium and digit tips. FGF2 synthesis is increased in embryonic ventricular cardiomyocytes in response to increased stretch due to pressure overload. Inhibition of FGF signaling impacts also vasculogenesis, pointing to partial functional redundancy in paracrine control of cell proliferation in the developing heart., E. Krejci, Z. Pesevski, O. Nanka, D. Sedmera., and Obsahuje bibliografii
Nitric oxide (NO) is an important endogenous neurotransmitter and mediator. It participates in regulation of physiological processes in different organ systems including airways. Therefore, it is important to clarify its role in the regulation of both airway and vascular smooth muscle, neurotransmission and neurotoxicity, mucus transport, lung development and in the surfactant production. The bioactivity of NO is highly variable and depends on many factors: the presence and activity of NO-producing enzymes, activity of competitive enzymes (e.g. arginase), the amount of substrate for the NO production, the presence of reactive oxygen species and others. All of these can change NO primary physiological role into potentially harmful. The borderline between them is very fragile and in many cases not entirely clear. For this reason, the research focuses on a comprehensive understanding of NO synthesis and its metabolic pathways, genetic polymorphisms of NO synthesizing enzymes and related effects. Research is also motivated by frequent use of exhaled NO monitoring in the clinical manifestations of respiratory diseases. The review focuses on the latest knowledge about the production and function of this mediator and understanding the basic physiological processes in the airways., M. Antosova, D. Mokra, L. Pepucha, J. Plevkova, T. Buday, M. Sterusky, A. Bencova., and Obsahuje bibliografii
Tissue betaine is an intracellular osmolyte that also provides a store of labile methyl groups. Despite these important biological roles, there are few data regarding tissue betaine content. We measured the betaine concentration of plasma and various tissues (brain, heart, lungs, liv er, kidney, spleen, intestine, reproductive tissues, skeletal muscle and skin) in male and female rats and assessed whether there were any gender-specific differences in betaine content or distribution and whether there was any relationship between tissue accumulation and plasma levels. Betaine was highest in the liver and kidney with values ranging from 1.6 to 9.5 mmol/l and 2.0 to 5.4 mmol/l, respectively. Plasma betaine concentrations were significantly lower than tissue levels except in the brain ( ≈ 25 % of plasma) and skeletal muscle (similar to pl asma). Regression analysis of the combined male and female data revealed a significant plasma-related accumulation of betaine in the heart, skin and skeletal muscle, while the lung, liver, kidney, spleen, and intestine showed significant plasma-related and plasma- independent accumulations of be taine. The betaine content of the skin, liver and kidney was no t significantly different between males and females, but in plasma and all tissues analyzed it was significantly higher in males (P<0.01)., S. Slow, M. Lever, S. T. Chambers, P. M. George., and Obsahuje bibliografii
Antidepressants, particularly tricyclic (TCA) antidepressants, may have cardiotoxic effects, such as cardiac arrhythmias, especially in patients with cardiovascular diseases. For most of TCA, no exact correlation between dosage, plasma levels and changes of ECG parameters of standard ECG has been found. So far, no relationship between dosulepine plasma levels and heart electric field parameters has been studied. We selected 18 female outpatient subjects diagnosed with recurrent depressive disorders, currently in the remission phase (HAMD < 10), without any cardiovascular disease. Patients were treated with daily dosulepine doses of 25-125 mg for 4-8 weeks. 30 heart electric field parameters were analyzed by Cardiag 128.1 diagnostic system as part of BSPM (Body Surface Potential Mapping). Acquired data were correlated with dosulepine plasma levels by means of Spearmanís rank order correlation test. Four ECG parameters showed a significant correlation with dosulepine plasma levels: QRS axis deviation in frontal plane (p=0.01), DIAM 40 max (p < 0.05), QRS-STT angle in transversal and left sagittal plane (p < 0.05). The demonstrated changes confirmed dosulepine influence on the early myocardium depolarization phase and the correlation of this effect with dosulepine dose (its plasma concentration). The higher the dosulepine level, the more marked are the changes of the QRS-STT angle in transversal and sagittal planes and the changes in the QRS axis deviation in frontal plane. Repeatedly recorded changes in the heart electric field were dosulepine-specific and dependent on its plasma levels., E. Kitzlerová, I. Paclt, J. Slavíček, K. Pišvejcová, M. Anders, A. Dohnalová, M. Balíková., and Obsahuje bibliografii
Microparticles are small fragments of the plasma membrane released by activated and/or apoptotic cells. In theory, all type of cells can shed microparticles representing a physiological process in the cell life. Mainly, microparticles generation has been studied in different cardiovascular pathologies due to the facility to obtain blood samples from individuals. Although microparticles have been considered as simply markers of several diseases, in the last decade, several studies support the hypothesis that they participate in the regulation of the cardiovascular system function by carrying biological messages between cells. Among the effects of microparticles, recent data show that they can be implicated in the modulation of neovascularization, an essential function of cells from cardiovascular system during either ischemic diseases or cancer development. Whereas during pathologies associated with ischemia an increase of neovascularization may have beneficial effects, anti-angiogenic strategies represent new approaches for manipulation of tumor development. Here, we give an overview of the mechanisms and factors involved in neovascularization, and finally, we look at the role and the consequences of the modulation of this process by microparticles in pathological situations., H. A. Mostefai, R. Andriantsitohaina, M. C. Martínez., and Obsahuje bibliografii a bibliografické odkazy