Konrad Rydzynski

Reproducible Comet Assay of Amorphous Silica Nanoparticles Detects No Genotoxicity

Genotoxicity of commercial colloidal and laboratory-synthesized silica nanoparticles was tested using the single cell gel electrophoresis or Comet assay. By using a carefully developed protocol and careful characterization of the nanoparticle dispersions, Comet assays were performed on 3T3-L1 fibroblasts with 3, 6, and 24 h incubations and 4 or 40 microg/ml of silica nanoparticles. No significant genotoxicity was observed for the nanoparticles tested under the conditions described, and results were independently validated in two separate laboratories, showing that in vitro toxicity testing can be quantitatively reproducible.

Selenium status of low-selenium area residents: Polish experience

The concentration of selenium (Se) in human organism varies widely between geographical areas depending on its content in soil and plants, dietary Se intake, bioavailability and retention, mineral interactions and other factors. The study includes healthy inhabitants of different regions of Poland; pregnant women, lactating women, children from 0 to 15 years of age and adults. Systematic determinations allow us to observe changes of the concentration of Se in time, which may be significant for developing preventive action. The results obtained confirm our thesis that Se concentration in the blood of the inhabitants of Poland depends on the region of the country. In recent years, in a considerable number of Polish inhabitants, the concentration of Se in blood plasma has been relatively low-about 50-55 microg/l, and the calculated daily dietary intake about 30-40 microg/day. The low levels of the element in the blood and urine are probably due to its deficiency in the diet.

DNA damage detected by the comet assay in the white blood cells of workers in a wooden furniture plant

The study was aimed at the assessment of genotoxic effects in workers of a wooden furniture manufacture, based on the level of DNA damage in white blood cells (WBC). The alkaline single cell gel electrophoresis assay (known as the comet assay) in individual cells was adapted for detecting damaged DNA in WBC. The level of DNA damage was determined as the percentage of cells with comets. It was assessed in cells before and after incubation in RPMI 1640 medium and CO(2) at 37 degrees C for 1 h to repair DNA breaks. Thirty-five woodworkers and 41 control subjects were studied. In the woodworkers, significantly more cells with DNA damage (21.5%) were observed than in the control persons (9.7%). A slight but significant decrease in the level of DNA damage was found in the WBC of woodworkers after incubation (17.2%). Significantly higher levels of damaged DNA was observed in woodworkers who either smoked (22.1%) or did not smoke cigarettes (20.8%) than in smokers (13.2%) and non-smokers (7.0%) from the control group. After incubation, a slight decrease in the level of DNA damage was found in both smoking and non-smoking woodworkers compared to the respective subjects in the control group. The increased levels of DNA damage observed in the woodworkers could be associated with the occupational exposure to wood dust in the furniture manufacture.

Relation between sources of particulate air pollution and biological effect parameters in samples from four European cities: An exploratory study

Given that there are widely different prevalence rates of respiratory allergies and asthma between the countries of Europe and that exposure to ambient particulate matter (PM) is substantial in urban environments throughout Europe, an EU project entitled “Respiratory Allergy and Inflammation Due to Ambient Particles” (RAIAP) was set up. The project focused on the role of physical and chemical composition of PM on release of cytokines of cells in vitro, on respiratory inflammation in vivo, and on adjuvant potency in allergy animal models. Coarse (2.5–10 μm) and fine (0.15–2.5 μm) particles were collected during the spring, summer and winter in Rome (I), Oslo (N), Lodz (PL), and Amsterdam (NL). Markers within the same model were often well correlated. Markers of inflammation in the in vitro and in vivo models also showed a high degree of correlation. In contrast, correlation between parameters in the different allergy models and between allergy and inflammation markers was generally poor. This suggests that various bioassays are needed to assess the potential hazard of PM. The present study also showed that by clustering chemical constituents of PM based on the overall response pattern in the bioassays, five distinct groups could be identified. The clusters of traffic, industrial combustion and/or incinerators (TICI), and combustion of black and brown coal/wood smoke (BBCW) were associated primarily with adjuvant activity for respiratory allergy, whereas clusters of crustal of material (CM) and sea spray (SS) are predominantly associated with measures for inflammation and acute toxicity. The cluster of secondary inorganic aerosol and long-range transport aerosol (SIALT) was exclusive associated with systemic allergy. The present study has shown that biological effect of PM can be linked to one or more PM emission sources and that this linkage requires a wide range of bioassays.

Selenium, zinc, and copper concentrations in the blood and milk of lactating women.

The aim of the study was to determine Se, Zn, and Cu concentrations in blood plasma and milk of lactating women from central Poland who were in different stages of lactation and to investigate the relationship between the content of trace elements in mothers’ blood and concentrations of microelements in their milk. Se and Zn concentrations in blood plasma of mothers were the lowest and Cu was the highest on the first 4 d of lactation (colostrum, n=43) and were found to be 34.9±11.8 µg/L, 0.51±0.13 mg/L, and 1.70±0.55 mg/L, respectively. The highest plasma level of Se and Zn and the lowest content of Cu could be observed between d 10 and 30 of lactation (mature milk, n=41), and were found to be 54.3±14.6 µg/L for Se (p<0.001), 0.76±0.20 mg/L for Zn (p<0.001), and 1.03±0.30 mg/L (p<0.001) for Cu.The results of Se, Zn, and Cu determination in breast milk samples demonstrate a pattern of decline in their concentration with advancing stages of lactation. We found out that Se, Zn, and Cu concentrations were the highest in colostrum (n=43) and amounted to 24.8±10.1 µg/L, 8.2±2.8 mg/L, and 0.45±0.11 mg/L, respectively. The content of all determined microelements declined significantly during the time of lactation. Statistically significant linear correlation was found between concentrations of Zn in blood plasma and milk in the first stage of lactation. Weak but statistically significant linear correlations were also found between plasma Se content in plasma and in transitional and mature milk of breast-feeding women.

DNA damage induced by nitrous oxide: study in medical personnel of operating rooms.

Occupational exposure to anaesthetics such as nitrous oxide (N(2)O) and halogenated hydrocarbons has been suggested to increase risk of genetic damage. However, the dose-dependency of genotoxic effects has not been unequivocally established and their relation to occupational exposure limit (OEL) remain obscure. In this study, the genotoxicity associated with occupational exposure to anaesthetics has been investigated in a group of 55 female nurses and 29 male anaesthesiologists active for at least 5 years in a working environment containing variable concentrations of N(2)O and halogenated hydrocarbons. 83 unexposed health care workers (52 female nurses and 31 male doctors) matched for age, gender, smoking habit and employment duration were included in the control group. Genotoxicity has been assessed using comet test. Concentrations of nitrous oxide, sevoflurane and isoflurane monitored by gas chromatography and mass spectrometry made possible to relate the extent of DNA damage to the level of exposure. Our results for the first time document a positive correlation between the DNA damage and the N(2)O levels in the ambient air. By contrast, no correlation has been observed between genotoxic effects and concentrations of sevoflurane and isoflurane. The extent of genetic injury was especially aggravated among nurses and anaesthesiologists exposed to N(2)O in concentrations exceeding OEL (180 mg/m(3)). We conclude that occupational exposure to N(2)O is associated with increased DNA damage and that the level of exposure plays a critical role in this regard.

Selenium levels, thiobarbituric acid-reactive substance concentrations and glutathione peroxidase activity in the blood of women with gestosis and imminent premature labour†

The aim of the study was to investigate antioxidant status, monitored by selenium and thiobarbituric acid-reactive substance concentrations in blood plasma, and glutathione peroxidase activity in erythrocytes and blood plasma in women with gestosis (n = 26), imminent premature labour (n = 48) and normal pregnancy (n = 23) during 19-38 weeks of pregnancy. Selenium concentrations in blood plasma were significantly higher in women with pathological pregnancies than in normal (45.5 +/- 10.5 micrograms l-1, p < 0.01 and 44.1 +/- 11.6 micrograms l-1, p < 0.05 vs. 38.6 +/- 8.3 micrograms l-1, respectively). In all groups of pregnant women Se concentrations were extremely low as compared with non-pregnant females. Glutathione peroxidase (GSH-Px) activity in blood plasma was significantly higher in complicated pregnancies than in healthy ones. There were no significant differences in thiobarbituric acid-reactive substance concentrations between all groups of pregnant women. Statistically significant correlations were found between blood plasma Se concentrations and GSH-Px activity in healthy pregnant (r = 0.53, p < 0.01), imminent premature labour (r = 0.39, p < 0.01), and non-pregnant females (r = 0.56, p < 0.001).

Behavioral Changes Following 4-Week Inhalation Exposure to Pseudocumene (1,2,4-Trimethylbenzene) in the Rat

Pseudocumene (1,2,4-trimethylbenzene, TMB) is a component of several solvent mixtures. During recent studies on rats we investigated the effect of a 4-week (6 h/day, 5 days/week) inhalation exposure to TMB at concentrations of 0, 25, 100, or 250 ppm on radial maze performance, open field activity, passive avoidance, active two-way avoidance, and shock-induced changes in the pain sensitivity reflecting the magnitude of the shock-induced fear response (hot plate test). The tests were performed between days 14 and 54 after the last exposure. The radial maze performance was not disturbed in any dose group. During testing in the open field grooming was significantly increased in rats exposed to 100 ppm TMB. In rats exposed to 100 and 250 ppm TNB, a foot shock applied after stepping off an elevated platform (a safe area) resulted in a significantly smaller increase in the step-down latency (i.e., passive avoidance, on days 3 and 7 after the foot shock) than in sham-exposed animals. Learning of a two-way active avoidance was slightly retarded in rats exposed to 250 ppm of TMB. Results of the hot plate test revealed no differences between groups in the paw sensitivity to heat (54.5 degrees C) before a 2-min intermittent food shock, but in rats exposed to 100 and 250 ppm of TMB the foot shock-induced fear response persisted apparently longer. These results suggest that inhalation exposure to TMB may lead to long-lasting disturbances in CNS functions.

Oxidative-stress markers in blood of lung cancer patients occupationally exposed to carcinogens

The study covered 152 lung cancer patients and 210 controls. The results of the study indicated decreased selenium (Se) concentrations and lowered activity of erythrocyte antioxidant enzymes (glutathione peroxidase, superoxide dismutase, glutathione-S-transferase) in the blood of lung cancer patients, as well as significantly increased concentrations of vitamin E in erythrocytes and thiobarbituric acid reactive substances in the plasma of the study population. Low plasma Se concentrations (<45.7 µg/L) enhance the estimated risk of lung cancer (odds ratio =3.047, p<0.001). A more precise exposure assessment is required to identify the association between lung cancer incidence and occupational exposure to carcinogens.

The inflammatory response in lungs of rats exposed on the airborne particles collected during different seasons in four European cities

Epidemiological studies have reported associations of ambient particulate air pollution, especially particulate matter (PM) less than 10 μm with exacerbations of asthma and chronic obstructive pulmonary disease. In an in vivo model, we have tested the toxicity of urban airborne particles collected during spring, summer, and winter seasons in four cities (Amsterdam, Lodz, Oslo, and Rome) spread across Europe. The seasonal differences in inflammatory responses were striking, and almost all the study parameters were affected by PM. Coarse fractions of the urban particle samples were less potent per unit mass than the fine fractions in increasing cytokine [macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)-α] levels and in reducing Clara-cell secretory protein (CC16) levels. This study shows that PM collected at 4 contrasting sites across Europe and during different seasons have differences in toxic potency. These differences were even more prominent between the fine and coarse fractions of the PM.