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General Physiology and Biophysics


Volume 28, 2009, No. 1

Content:


  Function of the cell surface molecules (CD molecules) in the reproduction processes
Katarína Fábryová 1), Michal Simon

1)Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 900 28 Ivanka pri Dunaji, Slovakia. katarina.fabryova@savba.sk.


Recent studies brought the evidences that some cell surface molecules associated with immune system (cluster of differentiation (CD) molecules) may be involved in the fertilization process. The experimental observations regarding the function of CD9, CD49f/CD29, CD46 and CD11b/CD18 have led to the construction of general hypothesis of fertilization comprising the interaction of these CD molecules in binding and fusion of sperm and egg. The models for the role of CD9 and CD49f/CD29 in the fertilization are based on the interaction of tetraspanin CD9 and integrin α6β1 (CD49f/CD29) via fertilin in sperm-egg binding and fusion. The model for the role of integrin CD11b/CD18 and CD46 in fertilization is based on the interaction of these two molecules through complement C3 fragments which may serve as bridging ligands between sperm CD46 and oocyte CD11b/CD18 and facilitate apposition of the sperm inner acrosomal membrane with oolemma.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 1-7.

 
  Spectrum of DHCR7 mutations in Slovak patients with Smith-Lemli-Opitz syndrome and detection of common mutations by PCR-based assays
Katarína Kolejáková 1), Robert Petrovič, Ján Futas, Peter Turčáni, Darina Ďurovčíková, Ján Chandoga

1)Centre of Medical Genetics, University Hospital, Mickiewiczova 13, 813 69 Bratislava, Slovakia. katekole@centrum.sk.


The Smith-Lemli-Opitz syndrome (SLOS), an autosomal recessive disorder associated with multiple developmental malformations, is caused by a large spectrum of mutations in the DHCR7 gene. Mutations in the DHCR7 gene lead to a 7-dehydrocholesterol reductase deficiency, which is the final enzyme in the pathway of the cholesterol biosynthesis. Reduced cholesterol levels and elevated concentrations of its precursor 7-dehydrocholesterol in plasma and tissues are the major biochemical hallmarks of this disorder. In all patients a biochemical analysis of blood sterols using the gas chromatography/mass spectrometry was performed to confirm the clinical diagnosis of SLOS. We have also determined the mutational spectrum of DHCR7 gene in 17 Slovak patients. We identified six different mutations: nonsense mutation W151X and missense mutations V326L, L109P, G410S, R352Q, Y432C. Mutations W151X and V326L accounted for 76% of the SLOS alleles in Slovak population. The Slovak mutational spectrum is similar to that observed in other Central European countries. We also report simple polymerase chain reaction (PCR)-based assays that allow efficient and rapid mutation analysis.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 8-15.

 
  The correlation between the plasma nitric oxide levels and QT/QTc interval in conscious rabbits
Tennur Atabay 1), Metehan Uzun

1)Department of Physiology, Institute of Health Sciences, Faculty of Veterinary Medicine, University of Kafkas, Kars, Turkey..


The current study was undertaken to investigate the effects of NOx (plasma concentrations of nitrate plus nitrite which are plasma nitric oxide (NO) metabolites) over QT interval and to determine the level of correlation between them in conscious rabbits. For this purpose, twenty-one New Zealand rabbits (5–7 months old) were used and randomly assigned into the following three groups: control (CG; n = 7, 1 ml isotonic NaCl solution per animal/day), L-arginine (ARG-G; n = 7, L-arginine solution 200 mg/kg/day) and L-NAME (NAME-G; n = 7, L-NAME solution 100 mg/kg/day). Injections were performed intraperitoneally at 9:00 a.m. for 9 days. Blood samples were collected 2 h after the injections on day 1, 5 and 9 and the concentration of plasma NOx was determined using a colorimetric method. ECG was also recorded 2 h after the injection on 1st, 5th and 9th days. The heart rate, QT intervals, corrected QT intervals (QTc) and QT dispersion (QTd), QTc dispersion (QTcd) values were calculated from the ECG recordings. Statistically significant differences were observed between HR, QT and QTc values in all groups for all days (p < 0.001). QTd and QTcd values were found statistically significant different in NAME-G compared to CG and ARG-G (p < 0.001). It was also determined that there was a statistically significant correlation between the NOx and HR and QT and QTc in all days. It is concluded from this study that NO is an important molecule for the electrical activation of heart and has effects on the duration of QT/QTc interval, which should be taken into consideration by the physicians. In addition, application of the L-arginine should be further studied.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 16-23.

 
  Evaluation of remodeling in left and right ventricular myocytes from heterozygous (mRen2)27 transgenic rats
Christophe Chouabe 1), Estelle Ricci, Mazen Kurdi, Claude Legrand, Giampiero Bricca, Robert Bonvallet

1)CNRS UMR 5123, Physiologie des Régulations Energétiques, Cellulaires et Moléculaires, Campus de la Doua, Université de Lyon 1, 69622 Villeurbanne, France. christophe.chouabe@univ-lyon1.fr.


Cardiac remodeling was assessed both in the pressure-overloaded left ventricle and in the normotensive right ventricle of hypertensive transgenic rats (mRen2)27 (TGR27). The present study combined histology, electrophysiology, molecular biology and biochemistry techniques. A significant increase in action potential (AP) duration was recorded both in right and left ventricular myocytes wheareas only in the latter ones were hypertrophic. The increase in AP duration is mainly supported by the reduction of the transient outward K current (Ito) density since no significant modification was observed for the L-type calcium current (ICa,L), the sodium-calcium exchange current (INCX), the delayed rectifier current (IK) and the inward rectifier current (IK1). The lower amplitude of Ito current was associated with a lower Kv4.3 protein expression both in right and left ventricles while Kv4.3 mRNA levels was decreased only in left ventricle. Thus, a differential ventricular remodeling takes place in the TGR27 model. The possible cause of electrical remodeling in right ventricular myocytes of TGR27 is discussed.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 24-38.

 
  Acute diabetes mellitus and its influence on renal Na,K-ATPase in both genders
Veronika Javorková 1), Lucia Mézešová, Jana Vlkovičová, Norbert Vrbjar

1)Institute for Heart Research, Department of Biochemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 840 05 Bratislava 45, P.O.Box 104, Slovakia. usrdveja@savba.sk.


Due to the importance of renal Na,K-ATPase in maintaining the sodium homeostasis in the organism, its activity and abundance is intensively studied in condition of diabetes mellitus. The main subject of this study was the investigation of properties of renal Na,K-ATPase and abundance of its α1 subunit in view of possible gender-dependent differences in male and female diabetic rats. Diabetes was induced by a single intraperitoneal dose of streptozotocin in a dose of 65 mg·kg–1. The acute diabetes lasting 8 days induced a significant increase in Na,K-ATPase activity accompanied by significant gender specific increase in Km value indicating a worsened affinity of ATP-binding site in female rats. In addition, our present experiments, revealed a significantly higher abundance of renal Na,K-ATPase α1 subunit in diabetic rats of both genders amounting 94% increase in males and 107% in females. But, not all of the newly synthesized enzyme molecules are fully active, as the increase in the number of active molecules is smaller (representing 23% in males and 20% in females) as indicated by lower increase in Vmax values.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 39-46.

 
  Protein oxidation under extremely low frequency electric field in guinea pigs. Effect of N-acetyl-L-cysteine treatment
Göknur Güler 1), Zerrin Türközer, Elcin Ozgur, Arin Tomruk, Nesrin Seyhan, Çimen Karasu

1)Gazi Non-Ionizing Radiation Protection Center, Department of Biophysics, Faculty of Medicine, Gazi University, 06500 Ankara, Turkey..


Modern age exposes humans to an increasing level of electromagnetic activity in their environment due to overhead power lines and transformers around residential areas. Studies have shown that treatment with antioxidants can suppress the oxidative damage induced by electromagnetic fields in various frequencies of the non-ionizing radiation band. In this study, we detected protein carbonyl content (PCO), advanced oxidation protein products (AOPP) in liver and 3-nitrotyrosine (3-NT) levels in plasma of guinea pigs in order to investigate the effects of N-acetyl-L-cysteine (NAC) administration on oxidative protein damage induced by power frequency electric (E) field (50 Hz, 12 kV/m, 7 days/8 h/day). We also analyzed hepatic hydroxyproline level to study protein synthesis. According to the findings of the present study, no statistically significant changes occurred in PCO, AOPP and 3-NT levels of the guinea pigs that were exposed to the E field with respect to the control group. However, liver hydroxyproline level was significantly diminished in the E field exposure group compared to the control and PCO, hydroxyproline and 3-NT levels changed significantly in the NAC-administrated groups.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 47-55.

 
  Comparison of in vitro chondrogenic potential of human mesenchymal stem cells derived from bone marrow and adipose tissue
Ľuboš Danišovič 1), Ivan Varga, Stefan Polak, Marcela Uličná, Lívia Hlavačková, Daniel Bohmer, Ján Vojtaššák

1)Institute of Medical Biology and Genetics, Faculty of Medicine, Comenius University in Bratislava, Sasinkova 4, 811 08 Bratislava, Slovakia. lubos.danisovic@fmed.uniba.sk.


In the present work, the human bone marrow and adipose tissue-derived mesenchymal stem cells (MSCs) were isolated and expanded under in vitro condition. After their phenotypic analysis, the chondrogenic differentiation was induced by using of the three-dimensional culture system without supplementation of growth factors, and their chondrogenic potential was compared. Obtained results proved that both types of MSCs undergo the process of chondrogenic differentiation. Comparative analysis showed that chondrogenic potential of adipose tissue-derived MSCs was slightly decreased in comparison with bone marrow-derived MSCs. However, both evaluated MSCs may play important role in the cartilage tissue engineering.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 56-62.

 
  Membrane transport and apoptosis-related proteins in radiation-associated acute myeloid leukemia following the Chornobyl accident
Sergiy Klymenko 1), Iryna Ilyenko, Natalya Golarnik, Oksana Maznichenko, Albert Breier, Dimitry Bazyka

1)Research Centre for Radiation Medicine, 53 Melnikova, 04050 Kyiv, Ukraine. klymenko_sergiy@yahoo.co.uk.


We report on the results of multidrug-resistance transporters (P-glycoprotein, LRP, and MDR1), and apoptosis-related proteins (Fas, Bcl-2, Bax, p53, and Bcl-XL) expression analysis of 56 acute myeloid leukemia (AML) patients by flow cytometry. Of these, there were 21 persons exposed to ionizing radiation due to the Chornobyl accident with radiation-associated and 35 patients with spontaneous AML. Leukemic cells in patients with radiation-associated AML more often overexpressed antiapoptotic protein Bcl-2 (12/21 vs. 6/35, p < 0.005) and less often demonstrated expression of Fas receptor (12/21 vs. 30/35, p < 0.05). Moreover, leukemic cells were simultaneously Fas negative and Bcl-2 positive in 4 out of 21 patients exposed to ionizing radiation but none of spontaneous cases had similar phenotype (p < 0.05). Patients with radiation-associated AML compared to spontaneous cases more often were P-glycoprotein positive (12/20 vs. 9/31, p < 0.05). P-glycoprotein overexpression significantly correlated with the resistance of the disease to chemotherapy in patients with radiation-associated AML (p < 0.05).

General Physiology and Biophysics. Volume 28, 2009, No. 1: 63-69.

 
  Photodynamic activity of pyropheophorbide methyl ester and pyropheophorbide a in dimethylformamide solution
Saleh Al-Omari 1), Ahmad Ali

1)Department of Physics, The Hashemite University, Zarqa 13115, Jordan. salomar@hu.edu.jo.


Comparative spectroscopic study including the photosensitizers of pyropheophorbide methyl ester (PPME) and pyropheophorbide a (PPa) was performed to study their photodynamic activity. The investigated photosensitizers in a homogeneous system of dimethylformamide (DMF) are not photostable upon irradiation. The photobleaching efficiency of PPa is higher than that of PPME. Combining these results with the data obtained by measuring the singlet oxygen quantum yield and the hydroxyl group generation, it was revealed that the photobleaching efficiency could be correlated with the singlet oxygen quantum yield and the hydroxyl group production of the photosensitizer.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 70-77.

 
  Kinetic parameters for thermal inactivation of soluble peroxidase from needles of Serbian spruce Picea omorika (Pančić) Purkyně
Danijela Laketa 1), Jelena Bogdanović, Aleksandar Kalauzi, Ksenija Radotić

1)Faculty of Biology, University of Belgrade, Studentski trg. 3–5, 11000 Beograd, Serbia.


Thermal inactivation of peroxidase (POD) in an extract of Picea omorika (Pančić) Purkyně needles initiated by heat treatment was studied. This is the first study of this kind on a conifer species. Non-linear regression analysis was applied on the inactivation rate data, combining Mitscherlich and Arrhenius equations, treating time and temperature simultaneously as explaining variables. We determined the inactivation rate constant k, the Arrhenius energy of inactivation E and the remaining activity Cmin for the crude extract and for separated acidic and basic enzyme fractions, as well as for individual isoenzymes separated electrophoretically. A comparison of inactivation parameters for acidic and basic fractions shows that the thermal inactivation rate of the basic fraction is higher. The obtained value of inactivation energy for crude extract was between the values for acidic and basic isoenzyme fractions. One of the three analysed individual isoenzymes was characterised by a lower inactivation rate constant and higher inactivation energy. Another isoenzyme showed considerably higher level of remaining activity compared to the others, which identified it as the most resistant to high temperatures. The acquired values of Arrhenius energy of inactivation for POD in crude extract were intermediate, considering a range of POD values for various other plant species.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 78-85.

 
  The effect of an NO donor, pentaerythrityl tetranitrate, on biochemical, functional, and morphological attributes of cardiovascular system of spontaneously hypertensive rats
Ima Dovinová 1), Sona Cacanyiova, Viera Fáberová, Frantisek Kristek

1)Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Sienkiewiczova 1, 813 71 Bratislava, Slovakia. ima.dovinova@savba.sk.


The status of nitric oxide (NO) in spontaneously hypertensive rats (SHR) is unclear and its bioavailability may be affected by imbalance with reactive oxygen species. We studied cardiovascular effects of an NO donor, pentaerythrityl tetranitrate (PETN) in SHR. We used Wistar rats, SHR and SHR treated with PETN (200 mg/kg/day). After six weeks, myocardium and aorta from each group were taken for biochemical and iliac artery for functional and morphological study. Long-term administration of PETN to SHR increased cGMP level in platelets and did not affect blood pressure. In myocardium, the therapy resulted in a decrease in cardiac hypertrophy and MDA level, and the increased antioxidant enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx). In aorta, PETN decreased the NO-synthase activity and had no affect on the enzyme activities of SOD and GPx or on MDA level. In the iliac artery, the endothelium-dependent relaxation to acetylcholine was slightly improved and the maximum vasoconstriction to noradrenaline was decreased. Wall thickness, cross-sectional area, inner diameter, and wall thickness/ inner diameter measured after perfusion fixation (120 mmHg) were not affected. The small effect of PETN on cardiovascular system suggests that NO deficiency is probably not the main cause of pathological alterations in SHR.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 86-93.

 
  Morphofunctional characteristics of ACTH cells in middle-aged male rats after treatment with genistein
Verica Milošević 1), Vladimir Ajdžanović, Branka Šošić-Jurjević, Branko Filipović, Marjana Brkić, Nataša Nestorović, Milka Sekulić

1)Institute for Biological Research ", Siniša Stanković", 142 Despot Stefan Blvd., 11060 Belgrade, Serbia. dimi@ibiss.bg.ac.yu.


The soybean phytoestrogen, genistein, is increasingly consumed as an alternative therapeutic for age-related diseases. The aim of this study was to examine the morphofunctional characteristics of adrenocorticotrophic (ACTH) cells and blood concentrations of ACTH in sham-operated, orchidectomized and genistein-treated orchidectomized, 16-month-old Wistar male rats. Genistein (10 mg/kg/day) was administered subcutaneously for three weeks, while the control groups received the vehicle alone. Orchidectomy and genistein treatment decreased the volume density of ACTH cells and reduced (p < 0.05) circulating ACTH concentrations in comparison with control groups. In conclusion, genistein modulated the morphofunctional features of ACTH cells and decreased blood ACTH levels.

General Physiology and Biophysics. Volume 28, 2009, No. 1: 94-97.