Modulation of Na+,Ca2+ exchange current by EGTA calcium buffering in giant cardiac membrane patches

AbstractEffects of calcium buffering by EGTA were examined on sodium-calcium exchange currents (INaca) in inside-out giant cardiac membrane patches. Free calcium concentrations (Ca2+) were monitored with a calcium electrode and a fluorescent calcium indicator (Calcium Green-5N). With 1.8 μM cytoplasmic Ca2+, inward INaca increased 2-fold at −120 mV when EGTA concentration was increased from 0.1 mM to 10 mM (37°C and 140 mM extracellular sodium). Stimulation by EGTA was decreased or abolished under conditions of attenuated exchanger turnover rate: temperature < 30°C, extracellular sodium < 70 mM, and membrane potential > + 60 mV. EGTA concentration had no effect on outward INaca with 100 mM cytoplasmic Na+ and 0.8 μM cytoplasmic Ca2+, conditions under which the current inactivated by about 70%. EGTA (0.1–10 mM) and BAPTA (10 mM) inhibited the current by about 80% when the outward INaca was stimulated by 2 mM cytoplasmic ATP or by phosphatidylserine. The apparent Ki for EGTA was 0.2 mM. The electroneutral calcium ionophore, A23187, activated outward INaca even in presence of 10 mM EGTA. Our results are consistent with EGTA acting as a simple calcium buffer with no direct effect on the exchanger. At low concentrations of EGTA, inhibition of the inward INaca is expected due to submembrane calcium depletion by the exchanger; enhancement of the outward INaca at low EGTA concentrations is expected because submembrane calcium accumulates and activates INaca via regulatory calcium binding sites

Implementation of manipulative speech tactics in translation (based on English and Spanish journalistic texts)

The article is devoted to the analysis of the use of manipulative speech tactics, which are actively used in journalistic texts to form a certain impact on the target audience. The article explores the tactics on the example of English and Spanish speech techniques. The purpose is to study the influence of manipulative tactics on journalistic discourse. The research methodology includes an analysis of newspaper and journalistic texts popular in the United Kingdom and Spain. The article explores the strategies of manipulative speech techniques in political discourse. In journalistic texts, speech techniques have a peculiarity in manifestation in the multilevel perception by the reader. For political discourse, a special role is to use metaphors. Tactics based on speech techniques, including visual and expressive means (metaphorical models), are in every language culture. Manipulation here will be considered as a means used for the implicit implementation at the mental level of specific goals, intentions, and attitudes that do not coincide with those that the target audience currently has. Communication in political discourse has the only goal: to influence the object of influence. Therefore, the basis for using manipulative speech techniques is to use a strategy of influence and control by public consciousness

“Unerroric” of multistage discrete Fourier transform of digital signal without arithmetic operations of multiplication

There are the issues related to improving the quality of the spectral analysis of a polyharmonic signal by recurrent methods of the multistage discrete Fourier transform (DFT) based on differential digital filtering, which does not require multiplication. The concept of “unerroric” of this DFT of a digital signal is introduced only by addition and shift operations. The philosophical aspect of it is described. The aim of the study is to find a solution to the problem of improving the quality of spectral analysis of polyharmonic signal by recursive methods of multistage discrete Fourier transform based on differential digital filtering without performing arithmetic multiplication operations. Methods of research are the following: directed search and comparative analysis of results of multistage discrete Fourier transform on the basis of difference digital filtering of different orders at integer coefficients of this filtering. The study of the philosophical aspect of "unerroric" of digital methods of spectral analysis of a polyharmonic signal based on recurrence algorithms of multistage discrete Fourier transform with the help of difference digital filters with integer numeric filtration coefficients, which do not require arithmetic operations of multiplication, has shown that further development of the theory and methods of this filtration is necessary. As a result of the conducted research it was revealed that the degree of approximation to the desired level of accuracy of this spectral analysis can be raised by increasing the order of difference digital filtering with integer coefficients, as well as by selecting the order of difference of its algorithm. After philosophical comprehension of the regularities of "unerroric" of digital spectral analysis of polyharmonic signal by multistage discrete Fourier transform recurrence methods on the basis of difference digital filtering only by adding and shifting operations it was suggested to select the element base, technical characteristics of which consider these regularities, for software and hardware implementation of digital algorithms of multistage discrete Fourier transform without performing multiplication operations. It is shown that the use of programmable logic devices (PLD) can be considered as the best variant of the element base for hardware-software implementation of digital algorithms of spectral analysis of a polyharmonic signal by recursive methods of this multistage discrete Fourier transform

60-e - 70-e ... Zapiski o neoficial'noj žizni v Moskve

Neben der Zeitschrift Wiener Slawistischer Almanach erscheinen seit 1980 auch 2-3 Mal jährlich Sonderbände (seither 94 Ausgaben) mit literaturwissenschaftlichem oder linguistischem Schwerpunkt. Die literarische Reihe umfasst Monographien oder Tagungsbeiträge aus allen Bereichen der aktuellen slavischen Literaturwissenschaft und weit darüber hinaus (Medientheorie, Kulturwissenschaft, Literaturkritik). Die Beiträge oder Monographien erscheinen in der Regel in deutscher, russischer oder endlischer Sprache. Publikationsvorschläge an [email protected]</P

Experimental determination of thermal power radiator trademarks "Thermal" (JSC "Zlatmash" production)

Приводятся экспериментальные данные о тепловой мощности радиатора Торговой Марки «ТЕРМАЛЬ», свидетельствующие о перспективности их применения в качестве бытовых радиаторов для отопления гражданских и служебных помещений.The experimental data on the heat capacity of the radiator Trademark "Thermal", indicating the prospect of their use as domestic heating radiators for civil and office space

Membrane Transport Mechanisms Probed by Capacitance Measurements With Megahertz Voltage Clamp

We have used capacitance measurements with a 1-µs voltage clamp technique to probe electrogenic ion-transporter interactions in giant excised membrane patches, The hydrophobic ion dipicrylamine was used to test model predictions for a simple charge-moving reaction. The voltage and frequency dependencies of the apparent dipicrylamine-induced capacitance, monitored by 1-mV sinusoidal perturbations, correspond to single charges moving across 76% of the membrane field at a rate of 9500 s^(-1) at 0 mV. For the cardiac Na,K pump, the combined presence of cytoplasmic ATP-and sodium induces an increase of apparent membrane capacitance which requires the presence of extracellular sodium, The dependencies of capacitance changes on frequency, voltage, ATP, and sodium verify that phosphorylation enables a slow 300- to 900-s^(-1), pump transition (the E_1-E_2 conformational change), which in turn enables fast, electrogenic, extracellular sodium binding reactions, For the GAT1 (y-aminobutyric acid,Na,Cl) cotransporter, expressed in Xenopus oocyte membrane, we find that chloride binding from the cytoplasmic side, and probably sodium binding from the extracellular side, results in a decrease of membrane capacitance monitored with 1- to 50-kHz perturbation frequencies. Evidently, ion binding by the GAT1 transporter suppresses an intrinsic fast charge movement which mag originate from a mobility of charged residues of the transporter binding sites. The results demonstrate that fast capacitance measurements can provide new insight into electrogenic processes closely associated with ion binding by membrane transporters

Gut microbiota and carcinogenesis: actual aspects

The microbiota, together with the host, form a symbiotic relationship in which the microbiota plays a key role in maintaining the homeostasis of the human body, performing a number of significant functions such as energy metabolism, maturation and maintenance of the immune system, vitamin synthesis, regulation of bile acid reabsorption in the intestine, and much more. Scientific research in recent years has made a significant contribution to understanding the complex relationship between the microbiota and a range of human pathologies, including malignant neoplasms. The review considers the mechanisms of the possible influence of bacteria on the development and progression of cancer with an emphasis on the procarcinogenic properties of the microbiota. The most important factor in the mechanism of influence of the microbiota on carcinogenesis are toxins produced by microorganisms that induce direct damage to host cell DNA, causing DNA mutations, disruption of its exact replication, and also provoke an imbalance in the proliferation and apoptosis of host cells, their rapid aging and oncogenesis. The probable mechanisms of participation of microorganisms in the development of cancer through the activation of TLRs and NLRs receptors, which have a tumor-activating effect, are considered. A brief review is given on the mechanisms of carcinogenesis associated with the metabolic activity of the microbiota due to the processes of regulation of the production of secondary bile acids, activation of pro-carcinogenic compounds: phenols, ethanol, sulfides, ammonia, nitrosamines. The influence of the microbiota on the metabolism of sex hormones and the development of hormone-dependent cancers mediated by the mechanisms of enterohepatic circulation and estrogen deconjugation is described. The study of the carcinogenic mechanisms of action of the microbiota in the host organism opens up prospects for the development of new successful personalized approaches to the diagnosis, treatment, and prevention of cancer. Changing the composition of the microbiota should become a way to fight cancer, along with surgical treatment, chemotherapy, radiation therapy, targeted therapy and immunotherapy