The impact of air pollution on the levels of micronuclei measured by automated image analysis.

The measurement of micronuclei (MN) in human peripheral blood lymphocytes is frequently used in molecular epidemiology as one of the preferred methods for assessing chromosomal damage resulting from environmental mutagen exposure. In the present study, we evaluated the effect of exposure to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs), volatile organic compounds (VOC) and smoking on the frequency of MN in a group of 56 city policemen living and working in Prague. The average age of the participants was 34+/-6 years. The study was conducted on the same subjects in February and May 2007. The concentrations of air pollutants were obtained from personal and stationary monitoring. A statistically significant decrease in the levels of pollutants was observed in May when compared with February, with the exception of toluene levels measured by stationary monitoring. The frequency of MN was determined by the automatic image scoring (MetaSystems Metafer 4, version 3.2.1) of DAPI-stained slides. The results of the image analysis indicated a significant difference in the frequency of MN (mean levels 7.32+/-3.42 and 4.67+/-2.92, for February and May, respectively). Our study suggests that automatic image analysis of MN is a highly sensitive method for evaluating the effect of c-PAHs and confirms that there are no differences between smokers and nonsmokers. These results demonstrate the ability of c-PAHs to increase MN frequency, even if the exposure to c-PAHs occurred up to 60 days before the collection of biological material. Our work is the first human biomonitoring study focused on the measurement of MN by automated image analysis for assessing chromosomal damage as a result of environmental mutagen exposure.

Preferential silver reaction of nucleolar regions adjacent to fibrillar centers in ring shaped nucleoli of leukemic lymphocytes.

Silver stained proteins (SSPs) characteristic for interphasic nucleolus organizer regions (NORs) associated with fibrillar centers (FCs) and adjacent nucleolar regions of ring shaped nucleoli in leukemic lymphocytes exhibit a different sensitivity to the mild acid extraction including that with HCl. Such extractions permit a preferential visualization of fibrillar centers adjacent regions (FCARs) which are believed to represent sites of the ribosomal RNA (rRNA) transcription. The resistance of SSPs in FCARs to the extraction with HCl seems to be due to their binding to other components present in these regions. The extractibility of SSPs with HCl was influenced by the fixatives used. The largest resistance of SSPs to the extraction with HCl was noted after fixation with glutaraldehyde. In contrast, the largest extractibility of these proteins was observed after fixation with unbuffered formaldehyde.

Growth, food intake, motor activity and experimental cardiac necrosis in early malnourished male rats.

Male rats with protein energy malnutrition from birth to the 49th day of life (PEM) and then receiving normal diet ad libitum had lower body weights and relatively higher food intakes (g/100 g body weight) than controls (C). Spontaneous motor activity measured in rotation wheels from the 42nd day was higher in previously malnourished animals, but less food was consumed per gram of weight increment during this period by PEM rats as compared to C rats. The cardiotoxicity of isoprenaline administered at the age of 110 days was significantly lower, i.e. the cardiac damage was smaller in previously malnourished animals (PEM). This was most apparent when they were compared with inactive controls living in standard laboratory cages.

Influence of motor activity on the development of isoprenaline induced heart lesions.

The influence of spontaneous motor activity on the development of isoprenaline-induced heart lesions was studied in male rats of different ages. The extent of the lesions was evaluated quantitatively from raised accumulation of 203HgCl2 in the damaged tissue. Spontaneous activity in rotation cages rose with the animals, age and attained maximum values (6 562 m/d) at 3 months. The increase in motor activity in 10 months was very low and attained only 561 m/d. In all the experimental groups in which spontaneous activity was higher than this limit, a decrease in the cardiotoxic effect of isoprenaline was found after 2--3 weeks. The extent of the heart lesions in the individual animals was not proportional to the degree of their motor activity. The smallest myocardial damage was not found in animals which ran the most metres and vice versa. A marked decrease in the extent of the heart lesions occurred when the motor regimen was prolonged to 70 days. After a three days' break in the motor regimen, reduction of the cardiotoxic effect was still maintained. The extent of the heart lesions after 14 days' interruption corresponded to the values found in animals which were not allowed increased motor activity.