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M Cerná

Publications and source records attributed to M Cerná.

At least 37 records · Page 2Linked to original sources
PubMed2000

Genotoxicity of urban air pollutants in the Czech Republic. Part I. Bacterial mutagenic potencies of organic compounds adsorbed on PM10 particulates.

As part of a long-term program to investigate the impact of air pollution on the health of a population in a polluted region in Northern Bohemia, mutagenicity of extractable organic matter (EOM) from air particles PM10 was investigated by the means of Salmonella typhimurium indicator strains TA98 and YG1041 using the Ames plate incorporation assay. The air samples were collected in both the polluted and the control districts during the summers and winters of 1993-1994. In the polluted district, the collection was repeated during the winter of 1996-1997. The crude extracts from filters pooled according to the locality and the season were fractionated by acid-base partitioning into acid, base, and neutral fractions. The neutral fractions were further fractionated by silica gel column chromatography into five subfractions. The induction of revertants with the crude extracts was higher in winter samples than in summer samples. Both indirect-acting and direct-acting mutagenicity were observed. The indirect mutagenic potency of aromatic subfractions containing polycyclic aromatic hydrocarbons (PAHs) was generally low. The mutagenic potency detected with TA98 was more distinct only in the winter sample 1993-1994 from the polluted area, where the aromatic subfraction accounted for 23% of total mutagenicity. In both strains, the highest direct-acting mutagenicity was found in slightly polar fractions containing nitro-PAHs. The mutagenic potency detected with YG1041 was about two orders of magnitude higher than that detected with TA98. No substantial locational- or time-related variances in the mutagenic potencies of EOM, or in the spectrum of chemical components identified in individual fractions were found. The polluted district, in comparison to the control district, was found to have higher amounts of EOM, carcinogenic PAHs and mutagenicity of air particles (rev/m(3)). The fractionating process, combined with the bacterial mutagenicity test, confirmed that nitro-derivatives are the most important contributors to the bacterial mutagenicity of air particles. However, this study did not fulfill the expectancy to bring substantially new, clear-cut information on the composition and the biological activity of air pollution in both districts.

Adsorption↗
PubMed2000

Intestinal colonization leading to fecal urobilinoid excretion may play a role in the pathogenesis of neonatal jaundice.

BACKGROUND: Neonatal hyperbilirubinemia remains of concern because of the potential danger for the central nervous system. Because urobilinogen is a nontoxic derivative of bilirubin, the current study was conducted to examine the fecal excretion of urobilinoids and bilirubin in healthy newborns and infants, as well as their intestinal bacteria capable of reducing bilirubin, to assess a possible relation to serum bilirubin levels during the first weeks of life. METHODS: Bilirubin pigments, urobilinoids, and porphyrins were measured in stools of infants during the first week (group A, n = 60) and between the second week and the first 6 months of life (group B, n = 64). Microbiologic analysis of stools was performed in selected cases and bilirubin-converting activity of isolated bacteria was determined in vitro. RESULTS: Urobilinoids were detectable in stools of 57% of the neonates at day 5, but not before. However, fecal urobilinoid production on that day was only a fraction of that observed in adults (0.07 vs. 0.7-3.6 mg/kg per day), whereas at week 6 it increased significantly to an average of 0.9 mg/kg per day. Microbiologic analysis of neonatal stools revealed two novel bacterial strains of Clostridium perfringens and Clostridium difficile capable of reducing bilirubin to urobilinoids. CONCLUSIONS: Urobilinoids can be detected in stools of 57% of newborns at day 5 after delivery. However, the urobilinoid production during the first week of life is quantitatively insufficient to contribute significantly to the removal of bilirubin. Enhancement of the microbial conversion of bilirubin could decrease the intestinal concentration of bilirubin and may decrease the degree or enhance the removal of neonatal hyperbilirubinemia.

Bacteria↗
PubMed2000

The concentration levels of Cd, Pb, Hg, Cu, Zn and Se in blood of the population in the Czech Republic.

Knowledge of normal levels of concentrations of trace elements (Cd, Pb, Hg, Cu, Zn, and Se) in the population serves, among others, in design of regulations concerning health protection, determination of exposure limits and prevention of diseases caused by deficiency of trace elements. Concentrations of the named elements in whole blood of the Czech population were determined by means of atomic absorption spectrometry. The blood was collected during 1996-1998 from 1,216 blood donors (896 males and 320 females, average age 33 years) and 758 children (397 boys and 361 girls, average age 9.9 years). Mineralisation in a microwave digestion system was used in sample preparation. The accuracy of results was checked by means of the Control material Seronorm Whole Blood 404107 and Seronorm Serum 704121, Nycomed. Values of concentrations of the trace elements in blood found for adult (medians) were 0.7 microgram Cd.l-1, 800 micrograms Cu.l-1, 0.78 microgram Hg.l-1, 41 micrograms Pb.l-1, 76 micrograms Se.l-1, and 5,800 micrograms Zn.l-1, respectively. Statistically significant differences between men and women have been found in the concentrations of Cu, Hg, Pb, and Zn. In the juvenile population following medians of concentrations have been found: 0.15 microgram Cd.l-1, 1,047 micrograms Cu.l-1, 0.46 microgram Hg.l-1, 34 micrograms Pb.l-1, 69 micrograms Se.l-1, and 8,180 micrograms Zn.l-1. Statistically significant differences between boys and girls were found only in Pb and Zn concentrations. Concentrations of the studied elements correspond to the published values concerning population not exposed professionally.

Adult↗
PubMed2000

Five years of the system of monitoring the environmental impact on population health of the Czech Republic.

The data collected in the System of monitoring the environmental impact on population health of the Czech Republic in 1994-1998 were obtained routinely and in a stabilized manner in six subsystems: health consequences and risks related to air pollution, drinking water quality, noise, human dietary exposure, human exposure to toxic pollutants from the environment and monitoring of the health status and evaluation of selected indicators of demographic and health statistics. They represent a useful and comprehensive background for providing objective information on the health status of the Czech population and on pollution of different components of the environment in the Czech Republic. The results obtained in the period 1994-1998 show that no critical situation needing urgent countermeasures to be taken appeared in the localities monitored. However, some results are indicative of the necessity to take certain remedial measures to maintain all population exposure burdens as low as reasonably possible from the economical and social points of view. Generally, the admissible limit values and exposure limits are exceeded only sporadically in some localities while for most contaminants monitored only very low values compared to the limits can be found and such situations are mostly considered as non-systematic changes.

Adult↗
PubMed1999

Mutagenicity monitoring of airborne particulate matter (PM10) in the Czech Republic.

The mutagenic activities associated with inhalable airborne particulate matter (PM10) collected over a year in four towns (Czech Republic) have been determined. The dichloromethane extracts were tested for mutagenicity using the Ames plate incorporation test and the Kado microsuspension test both with Salmonella typhimurium TA98 and its derivative YG1041 tester strains in the presence and absence of S9 mixture. The aim of this study was to assess the suitability of both bacterial mutagenicity tests and to choose the appropriate indicator strain for monitoring purposes. To elucidate the correlation between mutagenicity and polycyclic aromatic hydrocarbons (PAHs), the concentration of PAHs in the air samples were determined by GC/MS. In general, the significant mutagenicity was obtained in organic extracts of all samples, but differences according to the method and tester strain used were observed. In both mutagenicity tests, the extractable organic mass (EOM) exhibited higher mutagenicity in the YG1041 strain (up to 97 rev/microg in the plate incorporation and 568 rev/microg in the microsuspension tests) than those in TA98 (up to 2.2 rev/microg in the plate incorporation and 14.5 rev/microg in the microsuspension tests). In the plate incorporation test, the direct mutagenic activity in YG1041 was on average 60-fold higher and in microsuspension assay 45-fold higher with respect to strain TA98. In the presence of S9 mix, the mutagenic potency in YG1041 declined (P<0.001) in summer, but increased in TA98 (P<0.05) in samples collected during the winter season. The microsuspension assay provided higher mutagenic responses in both tester strains, but in both strains a significant decrease of mutagenic potency was observed in the presence of S9 mix (P<0.001 for YG1041, P<0.05 for TA98 in winter). The mutagenic potencies detected with both indicator strains correlated well (r=0.54 to 0.87) within each mutagenicity test used but not (for TA98) or moderately (r=0.44 to 0. 66 for YG1041) between both of the tests. The mutagenic activity (in rev/m(3)) likewise the concentration of benzo[a]pyrene and sum of carcinogenic PAHs showed seasonal variation with distinctly higher values during winter season. A correlation between the PAH concentrations and the mutagenicity results for the plate incorporation, but not for the microsuspension tests was found. In samples from higher industrial areas, the higher mutagenicity values were obtained in plate incorporation test with TA98 and in both tests with YG1041 in summer season (P<0.05). According to our results, plate incorporation test seems to be more informative than microsuspension assay. For routine ambient air mutagenicity monitoring, the use of YG1041 tester strain without metabolic activation and the plate incorporation test are to be recommended.

Air Pollutants↗
PubMed1998

Spontaneous level of chromosomal aberrations in peripheral blood lymphocytes of control individuals of the Czech Republic population.

In order to assess the potential of cytogenetic determinations on peripheral blood lymphocytes as a mean of monitoring human population subjects to occupational and environmental exposures to genotoxins, accurate baseline data are required. During the past 20 years many results of the cytogenetic studies on peripheral blood lymphocytes from monitored occupationally exposed and non-exposed groups were obtained. At the time of blood drawing a questionnaire was administered. The questions covered a brief medical and family history including age, sex, medication, infectious diseases, smoking habits, X-ray examinations, alcohol consumption etc. Cytogenetic analysis from whole blood was carried out in short-term cultures. The cultivation time was 52 hours with all cells being in the first mitosis. A total of 100 well-spread metaphases containing 46 +/- 1 centromere were examined per donor on coded slides. Four categories of chromosome aberrations were evaluated: Chromatid and chromosome breaks, chromatid and chromosome exchanges. Cells bearing breaks or exchanges were classified as aberrant cells. Gaps were recorded but not scored as aberrations. Results of the cytogenetic analysis from control individuals (N = 5,430) indicated elevation of spontaneous frequency of aberrant cells (AB.C.) with age. We found 1.10% AB.C. (N = 551) in newborns; 0.71% AB.C. (N = 105) in the group 5-6 yr; 1.20% (N = 1,734) in the group 7-15 yr; 1.25% AB.C. (N = 239) in the group 16-19 yr and 1.59% (N = 2,801) in the group 20-63 yr.

Adolescent↗
PubMed1998

Risk assessment of the common air pollutants in Teplice, Czech Republic.

In the framework of the systematic investigation of the environment of the district of Teplice (Northern Bohemia), one of the most polluted regions in Europe, an attempt was made to estimate health risks to the inhabitants posed by the most common air contaminants (SO2, NOx, particulate matter). A meta-analysis of data published in recent papers dealing with health effects was performed. At first we weighed the number of positive and negative findings focusing on the following health indicators: prevalence of symptoms (coughing, wheezing), decreased respiratory function, prevalence of respiratory illness, and acute mortality. Only those categories in which the positive findings prevailed were taken into consideration and median values for LOAELs were calculated from the data referring to positive dose-response relationships. The exposure assessment was based upon a series of data on daily concentrations of the air contaminants in Teplice since 1975. Due to the somatic and respiration parameters, as well as to their habits, children between the ages of 8 and 10 appeared the most heavily exposed of all age groups. It was concluded that in real concentrations the risk is posed mainly from sulphur dioxide and, above all, from particulate matter.

Adolescent↗
PubMed1998

The use of YG bacterial tester strains for the monitoring of drinking water mutagenicity.

The organic extract from the 50 drinking water specimens taken in four cities were tested for mutagenicity in the Ames test (plate incorporation assay) using the parent TA98 and TA100 strains, and derived YG1041 and YG1042 strains. Four dose levels of extractable organic matter (EOM) with duplicate plate per dose were used. Slopes (revertants/mg EOM) were calculated by the Bernstein linear regression rejection model using GeneTox Manager software. The mutagenicity observed in the conventional strains TA98 and TA100 did not reach the significant increase in all tested samples with the higher mutagenic response found in TA100-S9. With the YG1041 and YG1042 tester strains, the results obtained demonstrated the clear-cut direct dose-related mutagenicity response in all tested drinking water extracts. Compared with TA98 and TA100 strains, the numbers of YG induced revertants were approximately 20 times higher. The high sensitivity of the YG tester strains could facilitate the mutagenicity monitoring in drinking water extracts, and help reduce the volume of sample required. However, to identify the chemical contaminants in drinking water responsible for the mutagenicity further studies are required.

Czech Republic↗
PubMed1997

Population-based biomonitoring in the Czech Republic--the system and selected results.

In the framework of the system of monitoring the environmental impact on population health, the concentration of lead, cadmium and selenium in blood and cadmium in urine was measured in adults (n = 670), children (n = 599) and umbilical blood (n = 549) using atomic absorption spectrophotometry. Furthermore, cytogenetic analysis of peripheral lymphocytes in all population groups under study was investigated. The median blood Pb level for the overall group of adults (47.8 micrograms/l, i.e. 0.23 mumol/1) was significantly higher in men (51.5 micrograms/l, i.e. 0.25 mumol/l). Smoking significantly influenced the blood Pb level in women. The 90th percentile in no group exceeded the value of 100 micrograms/l (0.48 mumol/l). The median blood Cd level in adults (0.9 microgram/l, i.e. 0.008 mumol/l) depends on smoking habit (1.25 micrograms/l, i.e. 0.01 mumol/l). The median urine Cd level was 0.585 microgram/g creatinine (0.59 mumol/mole creatinine) in adults and 0.37 microgram/g creatinine (0.37 mumol/mole creatinine) in children. The median blood Se level (53.5 micrograms/l, i.e. 0.68 mumol/l) was found to be higher in the group of non-smokers (57.5 micrograms/l, i.e 0.73 mumol/l). Lead and selenium level were significantly lower in the umbilical blood. Cytogenetic analysis results showed age-dependent average percentages of aberrant cells: 1.1% in umbilical blood, 1.27% in children and 1.71 in adults in line with the reference values for the Czech population.

Adult↗
PubMed1997

The use of a urine mutagenicity assay in the monitoring of environmental exposure to genotoxins.

Urinary bacterial mutagenicity was used as a biomarker of exposure to ambient air pollution in a group of women working outdoors in the city of Teplice (TP; Northern Bohemia) with higher levels of air pollution than a similar group of women in the city of Prachatice (PT; Southern Bohemia). The Salmonella typhimurium plate incorporation assay with the TA98 and YG1041 strains and microsuspension assay with the YG1041 strain were used for testing the urinary mutagenicity. PAH and their metabolites were analyzed by HPLC and GC/MS methods. The significantly higher values of most PAHs/metabolites detected in a TP group confirmed the differences of PAH exposures between both groups. In the plate incorporation assay, the TA98 strain was not able to detect the increase in urinary mutagenicity, but, for the YG1041 strain, the urinary mutagenicity was clearly determined with a significant difference in number of YG1041 + S9 revertants between the TP and PT groups. The microsuspension assay increased the mean response by about 10-fold over the standard plate test; however, no statistical difference between TP and PT groups was found due to high interindividual variability and small sample size. Comparing the urinary PAH/metabolites to urinary mutagenicity, significant correlations were observed between the plate incorporation mutagenicity results with the YG1041 revertants in the presence of metabolic activation and several of the urinary PAH/metabolites. On the contrary, in the microsuspension assay, several urinary PAH/metabolites correlated significantly with the YG1041 revertants only in the absence of metabolic activation. This may indicate the influence of different treatment conditions of assays on the urinary mutagenicity results. The results suggest the insufficient sensitivity of the TA98 tester strain to determinate low urinary level of mutagens. On the contrary, the use of the YG1041 tester strain increases the probability of detecting an effect of environmental exposure and seems to be applicable to biological monitoring. To definitely replace the standard plate incorporation assay with the microsuspension method is not possible without further comparative studies.

Adult↗
PubMed1997

System of monitoring the environmental impact on population health of the Czech Republic.

The data collected in the System of monitoring the environmental impact on population health of the Czech Republic in 1994 and 1995 were obtained routinely and in a stabilized manner in six subsystems: health consequences and risks related to air pollution, drinking water quality, noise, human dietary exposure, human exposure to toxic pollutants from the environment and the monitoring of the health state and evaluation of selected indicators of demographic and health statistics. They represent a useful and comprehensive background for providing objective information on the health status of the Czech population and on pollution of different components of the environment in the Czech Republic to other countries in Europe and worldwide to facilitate their commercial and cultural contacts. The results of the calendar year 1995 show that no critical situation needing urgent countermeasures to be taken appeared in the localities monitored. However, some results are indicative of the necessity to take certain remedial measures to maintain all population exposure burdens as low as reasonably possible from the economical and social points of view. The set of problems was identified as important also in 1994. Generally, the limit values and exposure standards are exceeded only sporadically in some localities while for most contaminants monitored only very low values compared to the admissible limits can be found.

Adolescent↗
PubMed1996

Genotoxicity of industrial effluents, river waters, and their fractions using the Ames test and in vitro cytogenetic assay.

Total and fractionated organic extracts from industrial effluents and Labe river water were tested for mutagenicity using the Ames test with TA98 strain and its YG derivatives (YG1021, YG1024 and YG1041) and cytogenetic analysis with human peripheral lymphocytes in vitro. The bacterial mutagenicity results showed a dose-dependent increase in numbers of TA98 revertants (10(5)) with effluent extracts and lower, but still significant, increase (10(3)) with river water extracts 6 km downstream. The further increase of YG revertants indicates the possible presence of nitroarenes and aromatic amines in the tested samples. In fractionated samples the significant mutagenicity was detected in two-polar acidic and polar basic-fractions, but the numbers of revertants in all effluent fractions were about one order of magnitude lower compared with total extracts results. The cytogenetic effect in human peripheral lymphocytes in vitro was not significant. The increase in chromosomal aberrations was not clearly dose-dependent and may reflect more the combination of toxic and clastogenic effects.

Cells, Cultured↗
PubMed1996

Biomarker studies in northern Bohemia.

Studies were conducted in northern Bohemia to simultaneously evaluate personal exposures to air pollution in the form of respirable particles containing polycyclic aromatic hydrocarbons (PAHs) and biomarkers of exposure, biological effective dose, genetic effects, and metabolic susceptibility. The series of biomarkers included PAH metabolites in urine, urine mutagenicity, PAH-DNA adducts in white blood cells determined by 32P-postlabeling, PAH-albumin adducts determined by enzyme-linked immunosorbent assay (ELISA), DNA damage in lymphocytes detected by comet assay, chromosomal aberrations, sister chromatid exchanges, and glutathione S-transferase M1 (GSTM1) genotypes. For these studies, a group of women who work outdoors about 30% of their daily time was selected. In a pilot study, a group of women from a polluted area of the Teplice district (northern Bohemia) was compared with a group of women from a control district of southern Bohemia (Prachatice). In a follow-up repeated-measures study, a group of nonsmoking women from Teplice was sampled repeatedly during the winter season of 1993 to 1994. Personal exposure monitoring for respirable particles (< 2.5 microns) was conducted for the 24-hr period before collection of blood and urine. Particle extracts were analyzed for carcinogenic PAHs. In the pilot study and in the follow-up study, a highly significant correlation between individual personal exposures to PAHs and DNA adducts was found (r = 0.54, p = 0.016; r = 0.710, p < 0.001, respectively). The comet parameter (percentage DNA in tail; %T) correlated with exposures to respirable particles (r = 0.304, p = 0.015). The GSTM1 genotype had a significant effect on urinary PAH metabolites, urine mutagenicity, and comet parameters (% T and tail moment) when the GSTM1 genotype was considered as a single factor affecting these biomarkers. Multifactor analysis o variance considering exposure and adjusting the data for GSTM1, age, and diet showed that the effect of personal exposures to PAHs on the variability of biomarkers (DNA adducts, comet parameters, urine mutagenicity) might be higher than the effect of the GSTM1 genotype. These results show the importance of considering all potential factors that may affect the biomarkers being analyzed.

Adolescent↗
PubMed1995

[The genetic map of HLA].

The major histocompatibility complex (MHC) gene products are known to play a fundamental role in foreign antigen presentation to the cellular immune system. The human major histocompatibility complex (HLA) spans about 4 million base pairs (4 Mbp) of DNA at chromosome position 6p21.3 and is one of the most intensively studied regions of the human genome, containing over 70 known genes. The HLA can be divided up into three regions: the class I sequences at the telomeric end of the complex; the class II loci at the centromeric end; and, between these, the class III genes including those for the complement components. The analysis of HLA has focused primarily on their structure and function. However, the quantitative differences in gene expression are also important, since quantitative variations of cell surface HLA influences immunoregulation and the expression of immunologically mediated diseases. Recently, biochemical and genetic studies have revealed the existence of tissue-specific cis-acting regulatory gene elements and trans-acting protein factors, capable of binding to the cis-acting regions, that govern HLA gene expression.

Chromosome Mapping↗
PubMed1995

Role of hydrophobic amino acids at position 74 of DRB1 chain in rheumatoid arthritis.

We have analyzed HLA class II alleles in a group of 153 Czech children with rheumatoid arthritis by PCR and hybridization with oligonucleotide probes. When we try to find a common sequence for all DRB1 alleles involved in juvenile and adult arthritis, we can notice hydrophobic amino acid at position 74, which is present in all these alleles, but not in nonsusceptible alleles, where is the hydrophilic amino acid at position 74. In our model, we speculate that the hydrophilic amino acid at position 74 creates a such kind of epitope which is not suitable for rheumatoid-associated peptides or T cells, and only hydrophobic amino acid can permit binding of these peptides or recognition by certain T cells. Analyses of the DPB1 sequences have shown that alleles which have a negatively charged amino acid at position 69, are more frequent in pauciarticular patients while those with a positively charged amino acid are more frequent in polyarticular patients. A positively charged amino acid at position 69 might present the same rheumatoid associated peptide as susceptible DRB1 alleles. The presence of more rheumatoid-associated peptide on the cell surface may cause conversion to more severe polyarticular forms. A negatively charged amino acid at position 69 could not present this peptide and a low concentration of the peptide on the cell surface presented just by DRB1 molecules keeps disease in a relatively benign condition of pauciarticular forms.

Adult↗