Prednosti i nedostaci različitih pristupa generiranja impulsa za elektroporaciju

Electroporator is a generator of electric pulses that is used for permeabilization of cells. There are five major concepts of electroporation design. Capacitor discharge, square wave generator, and analog generator are used to generate classical electroporation pulses that are longer than microsecond and pulse forming network, and resonant charging generator that are used to generate nanosecond electroporation pulses. The choice of an electroporator design is always driven by the biotechnological or biomedical application. Electroporators can be used for introduction of small (electrochemotherapy) and large molecules (gene electrotransfer), cell fusion, insertion of proteins into cell membrane, electroporation of organelles, pasteurization, tissue ablation etc. Basic concepts and foreseeable future developments in electroporator design are presented in this article.Elektroporator je generator impulsa koji se koristi za permeabilizaciju stanica. Postoji pet glavnih izvedbi elektroporatora. Pražnjenje kondenzatora, generator pravokutnog valnog oblika i analogni generator se koriste za klasične elektroporacijske impulse koji su duži od mikrosekunde, a mreža za formiranje impulsa i generator s rezonantnim nabijanjem se primjenjuju za generiranje nanosekundnih elektroporacijskih impulsa. Izbor izvedebe elektroporatora vođen je uvijek biotehnološkom ili biomedicinskom primjenom. Elektroporatori se mogu koristiti za ubacivanje malih (elektrokemoterapija) i velikih molekula (elektro genski prijenos), fuziju stanica, umetanje proteina u staničnu membranu, elektroporaciju organela, pasterizaciju, ablaciju tkiva itd. U radu su prikazani temeljni pristupi u izvedbama elektroporatora i predvidivi budući razvoj

Influence of hydralazine on interstitial fluid pressure in experimental tumors - a preliminary study

Background. Interstitial fluid pressure (IFP) has been recognised as the most important obstacle in macromolecular drug delivery to solid tumors. Our interest was to reduce differentialy tumor IFP with respect to IFP in surrounding and normal tissues in order to increase drug delivery to tumors aswell to increase tumor blood flow and potentialy tumor tissue oxygenation. In this preliminary study we used hydralazine, a longacting arterial vasodilator. Materials and methods. Measurements of interstitial fluid pressure were performed in vivo on CBA mice bearing SAF tumors using wick-in-needle technigue. Altogether eleven measurements were obtained on different animals with tumors of different size. Results. IFP in tumors after hydralazine administration was significantly lower than initial values in corresponding tumors. On average tumor IFP decreased for 33 % from initial value. On the contrary, no change in IFP in normal tissue was observed after hydralazine administration. Also, after injection of physiological saline instead of hydralazine there was no change in IFP neither in tumors nor in muscle. The results of our preliminary study on the effect of hydralazine on IFP in SAF tumor model is in accordance to previously reported studies. The decrease in tumor IFP was only observed in tumors, but not in muscle and surrounding subcutis. Conclusion. Hydralazine is a vasodilator which is capable of decreasing tumor IFP, reproducibly and with favorably long lasting dynamics

Requirements for a clinical electrochemotherapy device - electroporator

electroporato