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General Physiology and Biophysics


Volume 33, 2014, No. 3

Content:


  Most frequent molecular and immunohistochemical markers present in selected types of brain tumors
Romana Richterová 1), Jana Jurečeková, Andrea Evinová, Branislav Kolarovszki, Martin Benčo, Július De Riggo, Juraj Šutovský, Silvia Mahmood, Peter Racay, Dušan Dobrota

1)Department of Medical Biochemistry, Comenius University Bratislava, Jessenius Faculty of Medicine, Malá hora 4, Martin, Slovak Republic. romana.richterova@gmail.com.


Tumors of brain tissue and meninges create a heterogeneous group with various biological behavior, therapy management and differing prognosis. Some of these do not require treatment, some can be cured by surgery and some are rapidly fatal despite treatment. Despite huge progress in tumor research, innovations in diagnostic tools and therapy, prognosis remains, in case of malignant tumor types, very serious. There has been an increased understanding of molecular abnormalities occurring in primary brain tumors. Genome-wide analyses of tumors have improved the knowledge in tumor biology. The aim of the research is to explain the oncogenesis features thus leading to the use of new therapeutic modalities in order to prolong survival rate of patients and at the same time providing satisfactory life quality. This article offers a short review of the basic genetic alterations present with some histological types of brain tumors.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 259-279.

 
  The new low shear viscosimeter LS300 for determination of viscosities of Newtonian and non-Newtonian fluids
Peter Ruef 1), Jutta Gehm, Lothar Gehm, Claudia Felbinger, Johannes Pöschl, Navina Kuss

1)Department of Pediatrics, Clinic of Neonatology, University of Heidelberg, Germany. peter.ruef@t-online.de.


The low shear viscometer LS300 permits measurements of viscosity with the same precision of the LS30 but is now fully controlled by the windows based software. That allows to determine viscosity at several shear rates and to establish flow curves enabling determination of the viscosity of non-Newtonian fluids. The viscosity of whole blood of ten adults was determined via flow curves approximated by Casson. The sensitivity of the LS300 was evaluated by determining the viscosity of water at rising temperatures and by establishing flow curves of ten specimen of the same blood sample.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 281-284.

 
  Determination of whole blood and plasma viscosity by means of flow curve analysis
Peter Ruef 1), Jutta Gehm, Lothar Gehm, Claudia Felbinger, Johannes Pöschl, Navina Kuss

1)Department of Pediatrics, Clinic of Neonatology, University of Heidelberg, Germany. peter.ruef@t-online.de.


The LS300 viscometer permits automated measurements of viscosity at several shear rates of non-Newtonian fluids. We determined whole blood and plasma viscosity, aggregation, red blood cell deformability, and hematocrit of 66 healthy adults. The effects of the anticoagulants EDTA, heparin and citrate, and of centrifugation on blood viscosity (n = 12) and red blood cell geometry (n = 5) were investigated. With regard to the whole blood viscosity of adults, the best agreement was obtained by Casson's calculation compared to the methods of Ostwald, Bingham and Newton. The approximated flow curve of plasma showed only marginal differences between the method of Newton and Ostwald, whereas the latter gave the best quality of approximation. Centrifugation and the anticoagulants had a significant impact on whole blood viscosity and yield shear stress, whereas erythrocyte geometry remained unaffected. By linear regression of hematocrit with viscosity and yield shear stress, its impact on blood viscosity could be calculated in a hematocrit range of 0.32–0.50. Determination of whole blood viscosity should be performed in a standardized manner at several shear rates and without centrifugation of the blood samples.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 285-293.

 
  ERK inhibitor U0126 enhanced SDT-induced cytotoxicity of human leukemia U937 cells
Xiaomin Su 1), Xiaobing Wang, Kun Zhang, Shuang Yang, Qin Xue, Pan Wang, Quanhong Liu

1)College of Life Sciences, Shaanxi Normal University, Xi’an, Shaanxi, China. wangpan@snnu.edu.cn.


This study was to investigate the cell killing effect of chlorin-e6 (Ce6) mediated sonodynamic therapy (SDT) on human leukemia U937 cells and explore the role of ERK signal pathway in the process. The ultrastructure changes of U937 cells induced by ultrasonic irradiation were evaluated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The viability of cells was evaluated by viacount assay. Apoptosis was analyzed using flow cytometer as well as fluorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to analyze the expression of mitogen-activated protein kinase (MAPK). Intracellular reactive oxygen species (ROS) and mitochondria membrane potential (MMP) levels were also analyzed by flow cytometer after exposure. Our experiments showed that several distinct sonochemical effects were found after Ce6-mediated SDT treatment. Western blotting analysis indicated that the MAPK were activated. Especially, pre-treatment with ERK inhibitor U0126 could additionally enhance SDT-induced cell viability loss, early- and late-apoptotic rate, chromatin condensation, DNA fragmentation and caspase-3 activation. Besides, a mass of ROS accumulation and a conspicuous loss of mitochondrial membrane potential were detected in U937 cells. These findings suggested ERK signal pathway may deliver a survival signal which counteracts SDT-induced cell death, while combination with U0126 could significantly potentiate the SDT-induced cytotoxic effect in U937 cells.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 295-309.

 
  Spatial abilities are not related to testosterone levels and variation in the androgen receptor in healthy young men.
Aneta Kubranská 1), Silvia Lakatošová, Eva Schmidtová, Jaroslava Durdiaková, Peter Celec, Daniela Ostatníková

1)Institute of Physiology, Faculty of Medicine, Comenius University, Bratislava, Slovak Republic. aneta. kubranska@gmail.com.


Androgens modulate brain functions such as cognition, emotions and ability. Several studies have shown a correlation between testosterone levels and mental rotation. The aim of the present study was to confirm the influence of salivary testosterone levels, 2D/4D ratio (such as a putative marker of prenatal testosterone), and sensitivity of androgen receptor on the mental rotation in healthy young men. Seventy-five healthy young men (age, 21.86 year) volunteered in this study. Mental rotation scores of our subjects were assessed using the Vandenberg and Kuse Mental Rotation Test. The 2D/4D finger length ratio as an indicator of prenatal testosterone was used as an average measurement of both hands. Correlation analysis revealed no correlation between salivary testosterone levels and mental rotation. However, we have observed a trend towards a negative correlation. There were no statistically significant results between 2D/4D ratio and mental rotation or between polymorphic three-nucleotide (CAG) repeats and mental rotation tests. Future studies should focus on other genetic determinants of spatial abilities, potentially genes involved in testosterone metabolism.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 311-319.

 
  A chloride conductance exhibiting bicarbonate conductivity in renal inner medullary collecting duct cells
Juan Bolívar 1), César Lara-Figueroa, Ramón Martínez- Mayorquin, Florencio Monroy-Romero, Gabina Arenas

1)Department of Physiology, Faculty of Medicine, The National Autonomous University of Mexico, Mexico City, Mexico. jjboliv@unam.mx.


The anion conductance in primary cultures of rat inner medullary collecting duct cells was studied using perforated-patch whole-cell clamp technique. Depolarizations above 0 mv induced an outward anionic current with a time-dependent activation (Iovt) exhibiting a similar conductivity to Cl- and HCO3-. Iovt showed half-maximal activation around 32 mV with a slope factor of 23 mV, and showed a voltage-dependent activation time course that was well fitted by a sum of two exponential functions. Iovt was potentiated when external pH or external Ca2+ was increased and was blocked by external DIDS, DPC and furosemide. These characteristics of Iovt resemble that of the ClC-K1 channels mediated currents; however, anion substitution studies showed that Iovt exhibits a Br- > Cl- > I- > NO3- conductivity sequence, different from that observed in the ClC-K1 channels-mediated conductance. We suggest that, in inner medullary collecting duct cells, ClC-K channels of an unidentified type give rise to this Cl- and HCO3- conductance. This is the first study of a channel-mediated HCO3- current in kidney tubular cells.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 321-334.

 
  Ouabain modulation of snail Br neuron bursting activity after the exposure to 10 mT static magnetic field revealed by Higuchi fractal dimension
Srdjan Kesić 1), Ljiljana Nikolić, Aleksandar Savić, Branka Petković, Sladjana Spasic

1)Department of Neurophysiology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Despot Stefan Blvd. 142, 11060 Belgrade, Serbia.


Aim of this study was to investigate the application of normalized mean of the empirical Higuchi fractal dimension (FD) distributions, as a new approach to analyze the spontaneous bioelectrical activity of garden snail (Helix pomatia) Br neuron. The effect of ouabain on modulation of Br neuron bursting activity before and after the exposure to 10 mT static magnetic field (SMF) was observed by analyzing the following parameters: action potential (AP), interspike interval (ISI) and interbursting interval (IBI) components. Normalized mean of the empirical FD distributions were formed for the following experimental conditions: Control 1, Ouabain 1, Control 2, SMF 2, ASMF 2, Control 3, SMF 3 and Ouabain ASMF 3. Our main results have shown that ouabain without SMF induced increase in participation of AP and a decrease in participation of IBI components compared to the first control condition. However, in the presence of 10 mT SMF, ouabain-induced changes of measured parameters of Br neuron activity were less pronounced compared to the third control condition. We have shown that normalized mean of the empirical FD distributions is a useful method for detecting the changes in AP, ISI, and IBI components of complex bursting activity in altered physiological states.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 335-344.

 
  Thromboembolic injury and systemic toxicity induced by nicotine in mice
Mohamed Fahim 1), Abderrahim Nemmar, Suhail Al-Salam, Subramanian Dhanasekaran, Mohamed Shafiullah, Javed Yasin, Mohamed Hassan

1)Department of Physiology, Faculty of Medicine, UAE University, Al Ain, United Arab Emirates. m.fahim@uaeu.ac.ae.


Nicotine is involved in the pathogenesis of hematological and cardiopulmonary diseases. The understanding of the pathophysiological mechanisms underlying these undesirable effects is however unclear. Cigarette smoking, nicotine gums and patches are common sources for nicotine ingestion. We have investigated the nicotine’s effect on cerebral microvessel thrombosis and systemic toxicity. Mice received either nicotine (1 mg/kg, i.p.) or saline (control), once a day for 21 days. Briefly, after bolus intravenous fluorescein injection, a photo insult of cerebral microvessel was done. The platelet aggregation in microvessels was video recorded and analyzed. In conjunction, the plasma levels of superoxide dismutase (SOD), lactate dehydrogenase (LDH), liver enzymes, creatinine and blood urea nitrogen (BUN); and histopathological studies were carried out. Our results revealed a significant prothrombotic effect following nicotine exposure. Significant decrease in SOD indicates the occurrence of oxidative stress involved in the tissue damages and increase in the LDH emphasize the systemic toxicity. Substantial rise in the liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were observed. Lungs histology showed intra-vascular hemorrhagic infarction with necrosis, macrophage and neutrophils infiltration. Liver histology showed intravascular thrombosis and portal inflammation. We conclude that the sub-acute nicotine exposure causes an increase in thrombosis in cerebral microvessels and systemic, hepatic and pulmonary toxicity.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 345-355.

 
  Heart ventricles specific stress-induced changes in β-adrenoceptors and muscarinic receptors
Andrej Tillinger 1), Martina Novakova, Olga Krizanova, Richard Kvetnansky, Jaromir Myslivecek

1)Institute of Experimental Endocrinology, Centre of Excellence CENDO, Slovak Academy of Sciences, Vlarska 3, 833 06 Bratislava, Slovak Republic.


The left and right ventricles fulfill different role in heart function. Here we compare chamber specific changes in local catecholamine concentrations; gene expression and the receptor protein amount of all three β-adrenoceptors (β-AR) in rat right heart ventricles exposed to acute (1 session) and repeated (7 sessions) immobilization stress (IMMO) vs. previously observed changes in left ventricles. Density of muscarinic receptors as main cardio-inhibitive receptors was also measured. In the right ventricles, noradrenaline and adrenaline were increased. No β1-AR changes were observed, in spite of the increased sympathetic activity. On the other hand, we have found a decrease of β2-AR gene expression (reduction to 30%) after 7 IMMO and protein (to 59%) after 1 IMMO. β3-AR gene expression was increased after 7 IMMO. Muscarinic receptor density was not changed. When comparing correlation in left and right ventricles, there was strong correlation between adrenaline and β2-AR gene expression, protein and β3-AR gene expression in the left ventricles while only correlation between adrenaline and β2-AR mRNA and protein in the right ventricles was found. Our results show that maintenance of cardiac homeostasis under stress conditions are to a great extent achieved by a balance between different receptors and also by a balanced receptor changes in left vs. right ventricles. Taken together, decrease of cardio-stimulating β2-AR represents a new important mechanism by which β2-AR contributes to the heart physiology.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 357-364.

 
  Role of Mas receptor in renal blood flow response to angiotensin (1-7) in male and female rats
Mehdi Nematbakhsh 1), Tahereh Safari

1)Water and Electrolytes Research Center, Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran. nematbakhsh@med.mui.ac.ir.


Epidemiologic and clinical studies have shown that progression of renal disease in male is faster than that in female. However, the exact mechanisms are not well recognized. Angiotensin (1-7) (Ang 1-7) receptor, called "Mas", is an element in the depressor arm of renin angiotensin system (RAS), and its expression is enhanced in females. We test the hypothesis that Mas receptor (MasR) blockade (A779) attenuates renal blood flow (RBF) in response to infusion of graded doses of Ang 1-7 in female rats. Male and female Wistar rats were anesthetized and catheterized. Then, the mean arterial pressure (MAP), RBF, and controlled renal perfusion pressure (RPP) responses to infusion of graded doses of Ang 1-7 (100–1000 ng/kg/min i.v.) with and without A779 were measured in the animals. Basal MAP, RPP, RBF, and renal vascular resistance (RVR) were not significantly different between the two groups. After Ang 1-7 administration, RPP was controlled at a constant level. However, RBF increased in a dose-related manner in response to Ang 1-7 infusion in both male and female rats (Pdose < 0.0001), but masR blockade significantly attenuated this response only in female (Pgroup = 0.04) and not male (Pgroup = 0.23). In addition, A779 increased the RBF response to Ang 1-7 to a greater extent. This is while the increase in male was not significant when compared with that in female (Pgender = 0.08). RVR response to Ang 1-7 was insignificantly attenuated by A779 in both genders. The masR differently regulated RBF response to Ang 1-7 in the two genders, and the effect was greater in female rats. The masR may be a target for improvement of kidney circulation in renal diseases.

General Physiology and Biophysics. Volume 33, 2014, No. 3: 365-372.