Radioprotective effects: in vitro-in vivo

U radu su prikazani rezultati ispitivanja nutraceutika Gonebazola (“Bofarm” Beograd). Gonebazol sadrži vitamine (A, E, C, B3, B6) ekstrakt Echincea purpurea, polen, propolis, Ca, Mg, i aminokiseline u medu. Preparat je ispitan in vitro na ozračenim humanim limfocitima i in vivo na grupi volontera, zdravstvenih radnika, kojima je zbog hematološkog i nalaza hromozomskih aberacija stavljena privremena zabrana rada u zoni jonizujućeg zračenja. U in vitro uslovima smanjena je učestalost mikronukleusa za 69%, stepen lipidne peroksidacije za 50%, pri čemu je 25% ozračenih leukocita eliminisano apoptozom. In vivo ispitivanja su pokazala veliku sličnost sa in vitro efektima: vreme za regeneraciju kostne srži i perzistencija hromozomskih aberacija u limfocitima periferne krvi značajno je smanjeno. Iako preliminarni, rezultati in vivo ispitivanja su veoma ohrabrujući jer značajno smanjuju posledice kumulativnog efekta jonizujućeg zračenja.The results of investigation of benefitial radioprotective properties of nutraceutical Gonebazol-«Biofarm» Belgrade are presented in this study. Gonebazol is consisted of propolis, extracts of Phaseophycea digitata Khorbi, Ecninacea purpurea pulvis, Ca++, Mg++, vitamins B3, B6, A, E and C, amino acids, all conserved in honey. Nutraceutical was examined in vitro, on human irradiated lymphocytes, as well as in vivo on volunters, radiation technicians occupationally overexposed to ionizing radiation. In vitro investigations have shown remarkable radioprotective effects of Gonebazol: yield of radiation-induced micronuclei was reduced for 69%, which as followed with reduction of (MDA) for 50% and enhancement of apoptosis of leukocytes up to 25%. Although preliminary, results obtained in vivo have shown a great extent of similarity with in vitro effects: the incidence of chromosomal aberrations was lowered for less than 3 weeks. Baseline level of micronuclei was significantly reduced. Obtained results confirmed that supplementation with these carefully selected vitamins and minerals significantly improve genomic stability, which could used to avoid adverse effects of ionizing radiation.XXIII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, Donji Milanovac, 26-28. septembar 2005

Kinetics of heat denaturation of pepsin in a strong acid media

Heat aggregation of pepsin, in a strong acid media; involve the stage of nucleation, and the stage of growth of aggregates. The initial parts of the kinetic curves of aggregation were followed via monitoring the increase of absorbance (A) and were linearized as {dA/dt; t} and {A; t 2 } functions. The slope of these curves is proportional to the product rate constant of reversible denaturation and the rate constant of growth of aggregates. Addition of Al3+ ions display a lag period whose appearance is caused by intramolecular predenaturational changes in the pepsin molecule.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Redox Parameters in Blood of Thyroid Cancer Patients After the Radioiodine Ablation

The radioactive iodine (I-131) ablation is a well-accepted treatment modality for differentiated thyroid cancer patients. Unfortunately, the radiation induces the oxidative stress and damages cells and tissues, simultaneously activating the mechanisms of antioxidative defense. Since the mechanisms of those processes are not completely known, we wanted to examine the changes in the most important reactive oxygen species and antioxidative components, as well as their correlation and significance for lipid peroxidation. Our results showed that the level of thiobarbituric acid reactive substances was increased during the first 30 days after the radiotherapy. Among antioxidant components, superoxide dismutase was increased in the 3rd and 30th day; catalase in 7th and reduced glutathione in 3rd and 7th day after the radiotherapy. As regards the prooxidants, the reduction of hydrogen peroxide (H2O2) was recorded in 7th and 30th day, and superoxide anion radical (O-2(center dot-)) was unchanged after the exposure to I-131. These results indicate that differentiated thyroid cancer patients are under constant oxidative stress despite the observed increase in antioxidative and reduction in prooxidative parameters. The understanding of these early processes is important since their progress determines the latter effects of I-131 therapy

Chromosome analysis of lymphocytes from radiation workers in tritium-applying industry

Objectives: The frequency of chromosomal aberrations (CA) and micronuclei (MN) in peripheral blood lymphocytes was compared in two groups of persons occupationally exposed to tritium either through the use of luminous paints or in the weapons industry, with the aim of finding a correlation between the CA and MN assays, the extent of radiation hazard, and the duration of occupational exposure to chemical forms of tritium and the ability of the latter to induce hazards in human lymphocytes. Methods: CA analysis and the cytochalasin B micronucleus test were performed. Urinary tritium in both groups was measured using a liquid scintillation method. For purposes of comparison, 2 control groups (40 persons) were examined; 24 exposed individuals were matched to their controls according to age, sex, and smoking habits. Results: Values recorded for the frequency of CA in the group of workers handling tritium in luminous dial painting were 0.015 +/- 0.014 dicentrics/cell, 0.023 +/- 0.017 total unstable CA/cell, and 0.035 +/- 0.019 MN/binucleated cell. Urinary levels of tritium in this group of employees ranged from 1.35 to 9.43 MBq/l. As compared with their matched controls, in these workers the differences in the yield of CA as well as in MN were statistically highly significant (P LT 0.005 and P LT 0.003, respectively). The same parameters analyzed in workers employed in the armament industry gave values of 0.001 +/- 0.003 dicentrics/cell, 0.010 +/- 0.008 total unstable CA/cell, and 0.021 +/- 0.029 MN/binucleated cell. No detectable concentration of urinary tritium was found. As compared with their matched controls, in these workers the differences were also statistically significant (P LT 0.027 and P LT 0.012, respectively). The yield of CA, particularly the yield of dicentrics, was significantly higher (P LT 0.005) in the group of luminous dial painters as compared with the weapons industry workers. The difference found in the yield of MN between the two groups of workers was also statistically significant (P LT 0.084). Intercontrol differences in the yields of spontaneous CA as well as in MN were insignificant (P LT 0.683 and P LT 0.735, respectively). The results are discussed with respect to individual variations in the response to low doses of ionizing radiation, disorders in the handling of radionuclides, the duration of occupational exposure, and the chemical properties of the radionuclides used. Conclusion: Tritium in the chemical form of luminous paint is a more powerful clastogenic agent than tritium gas. Statistical analysis demonstrated that lymphocyte effects are due to the concentration of tritium in urine rather than to the duration of occupational exposure. Since the radiation hazard measured by the MN assay did not differ from that determined by the CA assay, the MN test can be recommended as a rapid assay for screening purposes in cases of occupational exposure to low radiation doses

Radiosensitivity of different aged human lymphocytes following electron irradiation in vitro

Cytochalasin B-blocking micronucleus test and chromosomal aberration analysis were used in this study to estimate the yield of individual variability in radiation response of different aged human lymphocytes. Both analyses were performed in three groups of adults, aged 18-65 years, on two sampling times, following irradiation by therapeutical dose of 2 Gy e- in vitro. No statistically significant difference in the induced yield of exchange aberrations between individuals under consideration was found. The yield of total aberration data showed greater variability and was statistically significant in the oldest group against two other adult groups. Regarding to fixation times no statistically significant differences in the induced yield of chromosomal aberrations (exchanges as well as total aberrations) were observed. The study has shown a slight increase in spontaneously occurring micronuclei with age. Almost equal mean number of radiation induced micronuclei was observed in the groups of adults aged 18-20 and 45-55 years. The highest mean number was observed in the oldest group. Evident variation in number of radiation induced micronuclei among individuals from the same age group was observed. The results of micronuclei assay for all individuals under consideration show statistically significant difference in the yield of radiation-induced micronuclei regarding the second fixation time. This study has shown that cytochalasin-B blocking micronucleus test is more sensitive assay than chromosomal aberration analysis for the estimation of individual radiosensitivity

Cytogenetic monitoring of pesticide sprayers

The induction of chromosome aberrations, micronuclei, and sister-chromatid exchanges (SCEs) was examined in cultured lymphocytes of 27 vineyard growers exposed to pesticides. Cytogenetic examinations were performed during the prespraying period, a month after spraying, and at the end of the spraying season. For comparison purposes, the same cytogenetic monitoring program was applied to two control groups. The first consisted of 15 individuals from a nearby town, and the second consisted of 20 volunteers living 200 km from the vine-growing area (reference control group). A positive, though low statistically significant (P LT 0.017) difference in the yield of unstable chromosomal aberrations in exposed sprayers was observed compared with both control groups during the prespraying period. The mean group value of micronuclei in exposed workers averaged 5.41 per 1000 binucleated cells, with individual means ranging from 0 to 15. In both control groups, the yield of micronuclei averaged 5.09 per 1000 binucleated cells, with individual means ranging from 1 to 10. No statistically significant (P LT 0.5) differences in yield of micronuclei were found in exposed subjects compared with both control groups. Significant individual variation (F = 14.09, P LT 0.000) in SCE frequency was observed in exposed subjects, as well as in both control groups (F = 14.09, P LT 0.000). A month after spraying, the average incidence of unstable aberrations in pesticide sprayers was 0.22%, and the yield of micronuclei averaged 17.78 per 1000 binucleated cells, with individual means ranging from 7 to 28. The incidence of micronuclei a month after spraying in exposed subjects was elevated (statistically significant at P LT 0.01) in comparison with the prespraying period, while the difference in the yield of chromosomal aberrations in exposed subjects was insignificant (P LT 0.5). At the end of the spraying season, the average incidence of unstable aberrations in exposed subjects was 0.79%, and the yield of micronuclei averaged 39.92 micronuclei per 1000 binucleated cells, with individual means ranging from 21 to 62. The appearance of more than one micronucleus per binucleated cell was related to the results on chromosome aberrations. The frequencies of chromosomal aberrations and micronuclei were significantly higher (P LT 0.001, P LT 0.000) in the exposed group than in their matched control groups. The yield of micronuclei in pesticide sprayers at the end of the season was higher than expected with respect to chromosomal aberration frequency, which provides some evidence that some of the micronuclei are induced by the spindle-inhibiting effects of pesticides. A statistically significant (P LT 0.003) difference in micronuclei in the first control group was observed compared with the reference control group at the end of the spraying season. With respect to the incidence of micronuclei in the control group in the vine-growing area, a poor but positive correlation (r = 0.074, P LT 0.104) with duration of the spraying season was found, which is probably due to airborne pesticides in the vine-growing area. SCE frequencies of the workers lymphocytes were not significantly changed due to the exposure. The yield of aberrations as well as that of micronuclei in exposed subjects correlated positively (r = 16, P = 0.016) with duration of exposure. (C) 1997 Academic Press

Radiosensitivity of different aged human lymphocytes following electron irradiation in vitro

Cytochalasin B-blocking micronucleus test and chromosomal aberration analysis were used in this study to estimate the yield of individual variability in radiation response of different aged human lymphocytes. Both analyses were performed in three groups of adults, aged 18-65 years, on two sampling times, following irradiation by therapeutical dose of 2 Gy e- in vitro. No statistically significant difference in the induced yield of exchange aberrations between individuals under consideration was found. The yield of total aberration data showed greater variability and was statistically significant in the oldest group against two other adult groups. Regarding to fixation times no statistically significant differences in the induced yield of chromosomal aberrations (exchanges as well as total aberrations) were observed. The study has shown a slight increase in spontaneously occurring micronuclei with age. Almost equal mean number of radiation induced micronuclei was observed in the groups of adults aged 18-20 and 45-55 years. The highest mean number was observed in the oldest group. Evident variation in number of radiation induced micronuclei among individuals from the same age group was observed. The results of micronuclei assay for all individuals under consideration show statistically significant difference in the yield of radiation-induced micronuclei regarding the second fixation time. This study has shown that cytochalasin-B blocking micronucleus test is more sensitive assay than chromosomal aberration analysis for the estimation of individual radiosensitivity

Effects of digoxin and gitoxin on the enzymatic activity and kinetic parameters of Na+/K+-ATPase

Inhibition of Na+/K+-ATPase activity from human erythrocyte membranes and commercial porcine cerebral cortex by in vitro single and simultaneous exposure to digoxin and gitoxin was investigated to elucidate the difference in the mechanism of the enzyme inhibition by structurally different cardiac glycosides. The drugs exerted a biphasic dose-dependent inhibitory effect on the enzyme activity in both tissues, supporting the existence of two sensitive Na+/K+-ATPase isoforms. The IC50 values for the low and high affinity isoforms were calculated from the inhibition curves using mathematical analysis. The Hill coefficient (n) fulfilled the relationship 1 LT n LT 3; suggesting cooperative binding of inhibitors to the enzyme. Kinetic analysis showed that digoxin and gitoxin inhibited Na+/K+-ATPase by reducing the maximum enzymatic velocity (V-max) and K-m, implying an uncompetitive mode of interaction. Both the isoforms were always more sensitive to gitoxin. The erythrocyte enzyme was more sensitive to the inhibitors in the range of low concentrations but the commercial cerebral cortex enzyme exerted a higher sensitivity in high inhibitors affinity concentration range. By simultaneous exposure of the enzyme to digoxin and gitoxin in combinations a synergistic effect was achieved by low inhibitor concentrations. An antagonistic effect was obtained with erythrocyte membrane enzyme at high inhibitors concentration

Differences in the Functional Activity and Redox Homeostasis Between the Left and Right Adrenal Gland of Rats Exposed to Chronic Isolation Stress

The aim of this study was to examine whether there are differences in adrenomedullary function in respect to the left and right sides in chronic stress conditions. We investigated how chronic stress isolation (CSI 12 weeks) affected the protein levels of key enzymes involved in adrenaline (A) synthesis (phenyl ethanolamine N-methyltransferase -PNMT), storage (vesicular monoamine transporters 2 - VMAT2) and degradation (catechol-O-methyltransferase - COMT), as well as the concentrations of A as an index for adrenomedullary function in the left and right adrenal medulla. Also, we examined the concentrations of malondialdehyde (MDA), protein levels of nuclear factor κB (NF-κB), and activity of catalase (CAT) in the left and right adrenal medulla. The investigated parameters were quantified by Western blot analysis, assay of enzymatic activity, and CAT Research ELISA kits. We found that CSI pro duced significantly increased levels of PNMT protein, and VMAT2 protein, as well as increased concentrations of A in the right adrenal medulla. However, we recorded that CSI increased protein levels of COMT and NF-κB, as well as the concentrations of MDA in the left adrenal medulla. Also, CSI decreased the activity of CAT only in the left adrenal medulla. Based on these results, it may b

Redox parameters in blood of thyroid cancer patients after the radioiodine ablation

The radioactive iodine (131I) ablation is a well-accepted treatment modality for differentiated thyroid cancer patients. Unfortunately, the radiation induces the oxidative stress and damages cells and tissues, simultaneously activating the mechanisms of antioxidative defense. Since the mechanisms of those processes are not completely known, we wanted to examine the changes in the most important reactive oxygen species and antioxidative components, as well as their correlation and significance for lipid peroxidation. Our results showed that the level of thiobarbituric acid reactive substances was increased during the first 30 days after the radiotherapy. Among antioxidant components, superoxide dismutase was increased in the 3rd and 30th day; catalase in 7th and reduced glutathione in 3rd and 7th day after the radiotherapy. As regards the prooxidants, the reduction of hydrogen peroxide (H2O2) was recorded in 7th and 30th day, and superoxide anion radical (O×-) was unchanged after the exposure to 131I. These results indicate that differentiated thyroid cancer patients are under constant oxidative stress despite the observed increase in antioxidative and reduction in prooxidative parameters. The understanding of these early processes is important since their progress determines the latter effects of 131I therapy. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III41007 and Grant no. 175007