Papers by Author: A. Djordjević

Abstract: Earlier investigation of fullerenol, C60(OH)24, features, in vitro, showed that fullerenol have strong antioxidative potential. In this work, we examined the influence of fullerenol as a potential antioxidative protector on doxorubicin induced cardiotoxicity in rats. Experiments were performed on adult Wistar rats, both gender. Animals were divided into six groups, each containing eight individuals. Doxorubicin was administrated i.v. (tail vein) in single dose of 8mg/kg. Fullerenol C60(OH)24 in treated animals was administrated i.p. (in doses 50, 100, 200 mg/kg) for 30 min. before application of doxorubicin. Control group (intact animals) was given saline (1 mL/kg). One group was treated only with fullerenol (100 mg/kg i.p.). Cardiotoxicity of doxorubicin as well as cardioprotective effects of fullerenol were evaluated following the heart function monitored by ECG recording during adrenalin i.v. infusion, and pathomorphological examination of the heart tissue. These evaluations were performed on the day 2 and 7 after doxorubicin administration. Both functional and pathomorphological investigations revealed no heart damage two days after given treatments. However, on the day 7 after doxorubicin injection, changes in cardiovascular reflexes to adrenalin as well as structural damage were manifest. The time for appearance of adrenalin-induced reflex bradicardia in ECG record was significantly longer in doxorubicin treated group in comparison with the control one. Also, pathomorphological examination of the heart tissue showed vacuolization of cardiomyocites. In fullerenol pretreated groups these described changes were ameliorated and corresponded to the control values. These results suggest that fullerenol might be potential cardioprotector in doxorubicin treated individuals.

Abstract: In vitro studies have demonstrated that fullerenol, a polyhydroxylated derivative of fullerene (C60(OH)n n = 12-26), has a high antioxidative potential. Since any radiation injury is mainly a consequence of the action of free radical species, the aim of this study was to examine radioprotective efficiency of fullerenol in whole-body irradiated mice. The experiment was performed on male, adult, white mice, whole-body irradiated with Xrays doses of 6 to 8 Gy (X-ray energy of 8 MV). Fullerenol C60(OH)24 was given in doses of 10 and 100 mg/kg i.p. 30 minutes before irradiation. The experimental groups consisted of 25-30 animals each. The survival rate and body mass gain of irradiated animals were monitored for 30 days after irradiation. The mean lethal times (LT50) of irradiated mice and mean lethal dose of X-rays were calculated and compared. The results showed that fullerenol C60(OH)24, in a dose of 100 mg/kg i.p., prolonged LT50 of irradiated mice. This effect was especially pronounced in mice irradiated with 7 and 8 Gy of X-rays. It seems that radioprotective efficiency of fullerenol C60(OH)24 is more marked in mice irradiated by higher doses of X-rays.

Abstract: The aims of this paper were to investigate cell growth activity of fullerenol C60(OH)24, its modulating effect on antitumor drug-induced cytotoxicity, and genotoxic influence of fullerenol at nanomolar concentrations. Human breast cancer cell lines, MCF-7 and MDA-MB-231, were treated with fullerenol at concentrations from 0.9 to 3.9 µg/ml alone or simultaneously with antitumor drugs (doxorubicin, cisplatin, taxol, and tiazofurin; IC50 concentrations) for 2 hours. Growth inhibition was evaluated by colorimetric SRB assay after recovery period of 24, 48, and 96 hours. The genotoxic examination was performed using sister chromatid exchange test and micronucleus assay, at fullerenol concentration ranging from 1 to 5 µg/ml. The fullerenol alone mildly inhibits the growth of both cell lines. Simultaneous administration of fullerenol and antitumor drugs strongly suppressed antitumor drug-induced cytotoxicity. The rate of cytotoxicity inhibition depended on fullerenol concentration, type of antitumor drug and cell line. Protection against doxorubicin and cisplatin was more pronounced than against taxol and tiazofurin. Fullerenol was not found to be genotoxic to investigated cell lines.

Abstract: Plasma reactor operating at low pressures (0.2-1 Torr) at 13.56 MHz has been developed with an idea to optimize the treatment of polymers, biological and textile materials. The reactor proved very effective in treatment of polymer surfaces and wool fabrics in order to improve wettability, efficiency of dyeing and printing as well as to reduce the felting shrinkage. It also gave good results in improving germination of seeds. The basic conditions that the reactor has to satisfy are: the energy of ions that hit the surface has to be low and the reactor should be efficient in production of active radicals. Two systems with different geometries were studied, both capacitively coupled plasma reactors operating at 13.56 MHz. Cylindrical geometry was selected in order to minimize the energy of ions reaching the surface. Modeling of the discharge was performed with an aim to verify the energy distribution function of ions. As a critical diagnostic test of the system, voltage and current probes were developed to check the operation mode of the discharge. Oxygen, air and argon were used with different results.