Neurofiziologija : studijų medžiaga

Vytauto Didžiojo universiteta

Application of electroporation method for introduction of bleomycin, DNA and photosensitizer ALFCS(4) into the cells in vitro as well as in vivo

It is known that under a strong electric field the cell undergoes membrane permeabilization that allows exogenous molecules to enter the cell more freely. It is also known that transfer of foreign molecules strongly depends on the parameters of electric pulses. Our in vitro studies showed that photosenstizers could be much more efficiently transferred to hepatoma cells using eight 1300 V/cm, 0.1 ms pulses. Combining with photosensitization of the cell we showed that cell viability was largely suppressed in comparison with the group in which AlFcS4 transfer was not facilitated by electric pulses. Applying the method of electroporation to transfer cytotoxic drug bleomycin into Lewis Lung carcinoma in vivo, we showed that the highest suppression of tumor growth was obtained when eight 1500 V/cm, 1 ms were applied. These pulses alone neither significantly suppressed tumor growth nor induced noticeable side effects of the surrounding tissues.[...]Gamtos mokslų fakultetasVytauto Didžiojo universiteta

Neurobiology [Rankraštis]

BIO 422Su bibliogrVytauto Didžiojo universiteta

Anticancer drugs electrotransfer into cells and tumors

Successful assays of cancer treatment based on electrotransfer of anticancer drugs by using electroporation demonstrate the effectiveness as well the perspective of this method in medicine and biotechnology. Here we present a short review of some our investigations and theoretical approaches concerning electrotransfer of anticancer drugs through the cell membrane. Together with the proposed theoretical models the practical applications based on them are discussed. The mechanism of electrotransfer of bioactive molecules analysis in this paper is founded mainly on the theory hydrophilic aqueous poresBiologijos katedraVytauto Didžiojo universiteta

Biologinių membranų elektroporacija

Pastaraisiais metais biofizikai, biologai, biotechnologai ir medikai domisi galimybe keisti biologinių membranų ir audinių savybes. Jau keli dešimtmečiai žinoma, kad biomembranos elektrinį laidumą ir pralaidumą ivairioms medžiagoms galima pakeisti biologinę ląstelę paveikus trumpu, tačiau stipriu elektros lauku. Reiškinys buvo pavadintas elektroporacija. Membranos pralaidumas padideja tiek, jog ne tik mažos, bet ir dideles molekulės gali patekti į ląstelės vidų. Pokyčiai membranoje gali būti pilnai grįžtami. Nors detalus šio reiškinio mechanizmas nėra aiškus, daugelis mokslininkų sutinka, kad veikiant stipriam elektros laukui membranoje susidaro hidrofilinės poros, kuriu diametras gali siekti iki kelių nm. Šiame straipsnyje pateikiama trumpa istorinė biologinių membranų elektroporacijos reiškinio tyrimų istorinė apžvalga, aptariami pasiūlyti elektroporacijos mechanizmai bei savybesIn recent years, manipulation of biological cells and cell tissue by external electric fields gains increasing importance for biophysics and cell biology in general and in biotechnology and medicine in particular. Especially, the method of electroporation has become a powerfool tool for cell manipulations. In electroporation cells are subjected to a pulsed high-voltage electric field, resulting in a temporary increase of cell membrane conductivity and permeability. This increase of permeability is large enough to allow both small molecules and macromolecules to enter or leave the cell. The process can be fully reversible and after resealing of the membrane, the cell regains its original state. Although the actual molecular mechanism underlying this process is not yet fully understood, most investigators agree that transient hydrophilic pores are responsible for a membrane's behaviour at elevated membrane voltages. Here, a short historical survey on the investigations of the influence of strong electric fileds on biological membranes has been presented. Main features of cell electroporation phenomenon and underlying mechanism have also been discussedVytauto Didžiojo universiteta

Применение методов ионизирующего и неионизирующего излучения в медицине и в биотехнологии

Biologijos katedraFizikos katedraKauno technologijos universitetasVytauto Didžiojo universiteta

Svarbiausios molekulės aksonų regeneracijoje

Suaugusiu žinduoliu centrines nervu sistemos (CNS) vystymasis glaudžiai siejasi su spontani ško gebejimo regeneruoti po pažaidu praradimu. Savo ruoštu periferines nervu sistemos (PNS) aksonai gebejim¹ regeneruoti po pa˛aidu i laiko vis¹ gyvenim¹. Santykis tarp augim¹ skatinančiu ir augim¹ slopinančiu veiksniu, ekspresuojamu tiek nerviniu, tiek ir ne nerviniu l¹steliu pa˛aidos aplinkoje, s¹lygoja regeneracijos sekmź. Dalis signaliniu molekuliu, taip pat ir augim¹ reguliuojantys veiksniai, yra gaminamos per vis¹ gyvenim¹, tačiau kai kuriu ju rai ka ypač padideja po CNS pa˛aidos, kai jos riboja aksonu augim¹ bei paveikia kitu l¹steliu elgsen¹. Efrinu, Semaforinu, Slit ir Netrinu klases molekules yra pagrindiniai veiksniai, trukdantys sekmingai CNS regeneracijai ir funkciju atkurimui. PNS neuronai inicijuoja reparacijos mechanizmus i karto po pa˛aidos atsiradimo ir sekmingai atkuria savo funkcijas net tada, kai pa˛aidos plotas siekia kelis centimetrus. Skirtumu tarp PNS ir CNS regeneracijos mechanizmu ir juose dalyvaujančiu veiksniu suvokimas yra svarbus tiek tiriant nervu sistemos plasti kum¹, tiek taikant naujas nervu sistemos pa˛aidu atkurimo strategijasDevelopment of adult mammal central nervous system (CNS) is closely related to loosing the ability spontaneously regenerate after injuries. On the other hand, peripheral nervous system (PNS) maintains its capability to regenerate after injuries entire lifespan. Ability to regenerate successfully is mainly determined by the balance of growth promoting and growth inhibiting factors, expressed by both neuronal and non-neuronal cells found in the injury site. Some of signaling cues involved in regeneration are expressed in adult CNS constantly, although expression of other factors occurs only in the injury site of adult mammal. Ephrins, Semaphorins, Slits and Netrins are among most important molecules involved in lack of success in regeneration of CNS. PNS neurons initiate reparation mechanisms right after development of injury, and are capable to recover functional activity even if an area of injury is more than several centimeters wide. Understanding of differences between CNS and PNS regeneration and factors involved in functional nervous system recovery are crucial for both in depth analysis of plasticity of adult mammal neural system, and for developing new treatment strategiesBiologijos katedraVytauto Didžiojo universiteta

The influence of medium viscosity for electrotransfer of small and large molecules into cells in vitro

The electroporation parameters used for efficient electrotransfer of drug and genes in many cases are obtained from in vitro studies. However, in vivo and in vitro conditions are very different: cells in vivo are densely packed and are surrounded by extracellular matrix, which in comparison to media used in vitro, has a different density and viscosity. These conditions in the tissues significantly affect the transfer of therapeutic molecules into the cells. In this study we analyzed whether various viscosity of medium can affect electrotransfer into cells of low and high molecular weight molecules in vitro. We showed that: i) Increasing the electroporation medium viscosity has no effect on cell viability, though it impeeds the delivery of molecules into the cell, ii) in comparison of small and large molecule intracelullar electrotransfer the medium viscosity has more influence for electrotransfer of large moleculesBiologijos katedraVytauto Didžiojo universiteta

Towards the mechanisms for efficient gene transfer into cells and tissues by means of cell electroporation

Intracellular gene electrotransfer by means of electroporation has been on the increase during the past decade. Significant progress has been achieved both in characterizing mechanisms of gene electrotransfer and in optimizing the protocol in many preclinical trials. Recently thi s has led to initiation of clinical trials of gene electrotransfer to treat metastatic melanomas. Further progress with the method in various clinical trials requires better understanding of mechanisms of gene electrotransfer. AREAS COVERED: A summary of recent progress in understanding mechanisms of gene electrotransfer, imparting general knowledge of cell electroporation and intracellular molecule electrotransfer. EXPERT OPINION: Gene electrotransfer into cells and tissues is a complex process involving multiple steps that lead to plasmid DNA passage from the extracellular region to the cell nucleus crossing the barriers of the plasma membrane, cytoplasm and nucleus membrane. Electrical parameters of pulses used for gene electrotransfer affect the initial steps of DNA translocation through the plasma membrane and play a crucial role in determining the transfection efficiency. When considering gene electrotransfer into tissues it becomes clear that other nonelectrical conditions are also of primary importanceBiologijos katedraVytauto Didžiojo universiteta