Biological response to the continuous occupational exposure to antineoplastic drugs and radionuclides.

PURPOSE: Antineoplastic drugs and radioiodine are recognized occupational risk factors affecting the genetic material of exposed persons. To assess cytogenetic damage and evaluate the presence of chromosomal instability during occupational exposure, a biomonitoring study was performed using a chromosomal aberration assay and a cytokinesis-block micronucleus (CBMN) test. MATERIALS AND METHODS: Blood samples from 314 healthy donors divided into 3 groups (control, exposed to antineoplastic drugs and exposed to radioiodine) were collected and cytogenetically analyzed. RESULTS: There was an increase in almost all analyzed parameters registered in the exposed persons. Chromatid breaks were higher in the subjects exposed to antineoplastic drugs, while dicentrics and premature centromere division (PCD) parameters were higher in nuclear medicine workers. The total number of micronuclei was higher in both groups of the exposed. The correlation analysis indicated the association of dicentrics, acentrics, chromosome and chromatid break with PCDs in both groups of the exposed, and micronuclei and nucleoplasmic bridges with PCDs in the subjects exposed to radioiodine. The discriminant analysis marked off PCD1-5 as the best predictor of exposure. Age, sex, sampling season and duration of exposure significantly influenced the analyzed parameters, while smoking habits did not show any influence. CONCLUSION: Based on the observed results, premature centromere division can be considered a valuable parameter of genotoxic risk for individuals occupationally exposed to low doses of ionizing radiation.

Serum Concentration of Prostaglandin E2 as a Diagnostic Biomarker in Patients With Silicosis: A Case-Control Study.

OBJECTIVE: Silicosis is a prevalent incurable pneumoconiosis caused by inhalation of silica dust. Study aimed to investigate inflammatory, hematological, and biochemical parameters as additional biomarkers for diagnosing or monitoring silicosis. METHODS: Research enrolled 14 workers with silicosis and 7 healthy controls (without exposure and silicosis). The serum level of prostaglandin E2, C-reactive protein, fibrinogen, biochemical, and hematological parameters were measured. The receiver operating characteristic curve was used to determine diagnostic sensitivity of each biomarker. RESULTS: Patients with silicosis have a significantly higher level of prostaglandin E2, erythrocyte, hemoglobin, and hematocrit than patients without silicosis. Prostaglandin E2, hemoglobin, and the erythrocyte count are significant in separating the silicosis cases from healthy controls. CONCLUSIONS: Prostaglandin E2 might be an adjuvant peripheral diagnostic biomarker for silicosis, while hematological parameters (erythrocytes, hemoglobin, and hematocrit) might be prognostic biomarkers.

RENEB Inter-Laboratory comparison 2017: limits and pitfalls of ILCs.

PURPOSE: In case of a mass-casualty radiological event, there would be a need for networking to overcome surge limitations and to quickly obtain homogeneous results (reported aberration frequencies or estimated doses) among biodosimetry laboratories. These results must be consistent within such network. Inter-laboratory comparisons (ILCs) are widely accepted to achieve this homogeneity. At the European level, a great effort has been made to harmonize biological dosimetry laboratories, notably during the MULTIBIODOSE and RENEB projects. In order to continue the harmonization efforts, the RENEB consortium launched this intercomparison which is larger than the RENEB network, as it involves 38 laboratories from 21 countries. In this ILC all steps of the process were monitored, from blood shipment to dose estimation. This exercise also aimed to evaluate the statistical tools used to compare laboratory performance. MATERIALS AND METHODS: Blood samples were irradiated at three different doses, 1.8, 0.4 and 0 Gy (samples A, C and B) with 4-MV X-rays at 0.5 Gy min-1, and sent to the participant laboratories. Each laboratory was requested to blindly analyze 500 cells per sample and to report the observed frequency of dicentric chromosomes per metaphase and the corresponding estimated dose. RESULTS: This ILC demonstrates that blood samples can be successfully distributed among laboratories worldwide to perform biological dosimetry in case of a mass casualty event. Having achieved a substantial harmonization in multiple areas among the RENEB laboratories issues were identified with the available statistical tools, which are not capable to advantageously exploit the richness of results of a large ILCs. Even though Z- and U-tests are accepted methods for biodosimetry ILCs, setting the number of analyzed metaphases to 500 and establishing a tests' common threshold for all studied doses is inappropriate for evaluating laboratory performance. Another problem highlighted by this ILC is the issue of the dose-effect curve diversity. It clearly appears that, despite the initial advantage of including the scoring specificities of each laboratory, the lack of defined criteria for assessing the robustness of each laboratory's curve is a disadvantage for the 'one curve per laboratory' model. CONCLUSIONS: Based on our study, it seems relevant to develop tools better adapted to the collection and processing of results produced by the participant laboratories. We are confident that, after an initial harmonization phase reached by the RENEB laboratories, a new step toward a better optimization of the laboratory networks in biological dosimetry and associated ILC is on the way.

Evaluation of Genetic Damage in Persons Occupationally Exposed to Antineoplastic Drugs in Serbian Hospitals.

INTRODUCTION: Although useful in the treatment of malignant cells, antineoplastic drugs (ANPDs) as chemical genotoxic agents, can interfere with normal cell physiology causing genetic damage and unfavourable health effects, especially in occupationally exposed persons. The Cytokinesis-block Micronucleus (CBMN) Cytome assay has been widely used in human biomonitoring studies as a reliable biomarker of chemical genotoxic exposure. OBJECTIVES: Our comprehensive research was conducted in order to evaluate micronuclei as a marker for preventive medical screening purposes for persons occupationally exposed to ANPDs. METHODS: Using the CBMN Cytome test, peripheral blood lymphocytes of 201 control and 222 exposed subjects were screened for genetic damage. RESULTS: Age and gender influenced micronucleus (MN) frequency, but smoking habit did not. The mean micronuclei frequencies and other parameters of the CBMN Cytome test [numbers of binuclear lymphocytes with one (MN1) or two (MN2) micronuclei] were significantly higher in the group of exposed persons. Positive correlation between duration of occupational exposure and MN frequency was revealed. CONCLUSIONS: The results of our study performed on a large sample confirmed the capacity of the CBMN Cytome assay to serve as a reliable biomarker of long-term ANPD exposure.

Differences Regarding Knowledge of Sexually Transmitted Infections, Sexual Habits, and Behavior Between University Students of Medical and Nonmedical Professions in Serbia.

Aim: The aim of this study is to assess the knowledge of sexually transmitted infections (STIs), sexual habits, and behavior among students of medical and nonmedical students in Serbia. Methodology: The cross-sectional study of 1,273 university students of four undergraduate institutions in Serbia, two of medical and two of nonmedical orientation. A standardized questionnaire, prepared in line with the questionnaire of the European health research-the second wave (European Health Interview Survey-EHIS wave 2), according to defined internationally accepted indicators, was used as a survey instrument. Results: Statistically significant difference (p < 0.001) between medical and nonmedical student groups was determined for the following parameters: naming four of five STIs (29.1 vs. 13.4%), knowledge about vaccines against some STIs (26.0 vs. 17.0%), relationship between HPV infection and cervical malignancy (48.2 vs. 16.7%) engaged in the sexual relations (87.9 vs. 76.4%), never used a condom (15.2 vs. 10.4%), underwent gynecological or urological examination (66.7 vs. 44.1%), and tested to one of STIs (10.5 vs. 4.9%). Conclusion: Both student groups have limited knowledge on possible consequences that risky sexual behavior has for reproductive health. Promotion of knowledge about STIs, awareness of all complications, and consequences of these infections certainly affect the reduction of risky behavior.

Oxidative Stress Profile in Genetically Confirmed Cases of Leber's Hereditary Optic Neuropathy.

The mechanisms of the complex pathophysiology of Leber's hereditary optic neuropathy (LHON) are still insufficiently clarified. The role of oxidative stress as an etiological factor has been proposed and demonstrated in vitro, but without conclusive data that rely on clinical samples. The aim of the study was to evaluate and characterize the existence of oxidative stress in the plasma of LHON patients and healthy individuals. Whole mitochondrial genome sequencing has been performed in order to identify primary LHON mutations. For the assessment of oxidative stress, the following biomarkers were determined in plasma: total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI), while oxidative damage of cellular proteins was estimated by quantifying advanced oxidation protein products (AOPP). All three primary LHON mutations (m.3460G > A, m.11778G > A and m.14484 T > C) were identified as a genetic cause of the disease, where the most prevalent one was m.11778G > A. LHON patients have a highly significant increase of TOS and a marked decrease of TAS levels, which suggests the existence of substantial oxidative stress. OSI is high in LHON patients, which definitely implies the presence of redox imbalance. Elevated level of AOPP in LHON patients refers to the significant deleterious effects of oxidative stress on cellular proteins. Oxidative stress parameters do not significantly differ between LHON individuals with different primary mutations. Both symptomatic and asymptomatic LHON patients have an augmented level of oxidative stress which suggests that primary mutations exhibit a pro-oxidative phenotype. Gender and smoking habit significantly influence examined biochemical parameters when LHON patients are compared with the control group. Different mitochondrial haplogroups are characterized by altered levels of OSI in LHON group. The absence of physiological correlations between redox parameters reflects the deregulation of homeostatic oxidative/antioxidative balance in LHON patients. This is the greatest series of LHON patients that were evaluated for oxidative stress and the first case-controlled study that evaluated TOS, TAS, OSI, and AOPP and their influence on disease phenotype. It is evident that the presence of oxidative stress represents an important pathophysiological event in LHON and that it could potentially serve as a circulatory biomarker for a therapy efficacy understanding.

The influence of redox status on inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation.

PURPOSE: Ionizing radiation (IR) can act on atomic structures, producing damage to biomolecules. Earlier investigations evaluating individual radiosensitivity in vitro were focused on cytogenetic biomarkers (chromosomal aberrations - CA and micronuclei - MN). Since IR can also cause oxidative damage by producing reactive oxygen species, the main goal of this investigation was to establish the influence of redox status on CA and MN frequency in human peripheral blood lymphocytes. MATERIALS AND METHODS: Blood samples from 56 healthy donors were irradiated at doses of 0, 0.75, 1.5 and 3 Gy and then analyzed cytogenetically and biochemically. RESULTS: The results showed inter-individual variability in all analyzed parameters, as well as dose-dependent increases in almost all of them. Correlation analysis indicated no association between CA, MN and oxidative stress parameters. However, findings for overall response (HRR) parameters showed that donors with lower values for parameters of antioxidant status had increased levels of cytogenetic damage and higher responses to irradiation and vice versa. CONCLUSION: Besides well-established cytogenetic biomarkers of radiation exposure, our results indicated promising future use for biochemical oxidative status parameters in routine radiation protection practice, since together they can provide a complete radiation response profile in cases of continuous low-dose exposure, as well as in a radiation emergency.

Chlamydia trachomatis screening in resource-limited countries - Comparison of diagnostic accuracy of 3 different assays.

INTRODUCTION: Commercially available assays were evaluated in order to determine diagnostic accuracy of Chlamydia trachomatis specific tests for screening. METHODS: The study included 225 sexually active men and women, who were tested for genital chlamydial infection in Institute of Public Health Kragujevac. Three screening tests were used: direct immunofluorescence (DIF) and rapid lateral immunochromatographic test (RT) for qualitative detection of chlamydial antigens and immunoenzyme (ELISA) test for detection of serum levels of anti-chlamydial IgA and IgG antibodies. Diagnostic efficiency of these tests were determined in relation to results obtained by RT-PCR method. RESULTS: Statistical significance between the results obtained by RT-PCR as a gold standard and DIF, RT and ELISA were analyzed using chi-square (χ2) test. Statistical analysis showed a significant difference between RT-PCR and analyzed screening tests: DIF (χ2 = 303; p < 0.001), RT (χ2 = 4.19; p = 0.041), serum IgA (χ2 = 4.19; p = 0.041) and serum IgG (χ2 = 67; p < 0.001) which indicates poor agreement between these tests. Large numbers of false positive (FP) and false negative (FN) results were observed for all tested assays. According to Youden's index, serum IgG and DIF testing demonstrated the most-balanced sensitivity-specificity rate. RT assay exhibits the highest expanded Youden's index, as well as the best overall diagnostic accuracy. CONCLUSIONS: None of evaluated screening tests can be recommended as individual method for the diagnosis of acute infection. We suppose that RT-PCR is unlikely to be a cost-effective screening strategy within the Serbian health system.

Cytogenetic surveillance of persons occupationally exposed to genotoxic chemicals.

Human genotoxic exposures can occur environmentally, occupationally, or medicinally. The aim of this study was to assess cytogenetic damage (chromosomal aberrations and micronuclei) in persons exposed to chemical agents in medical, agricultural, and industrial occupations. The results showed influences of age, gender, occurrence, and duration of exposure on the extent of cytogenetic damage, but no influence of smoking. Persons exposed to pesticides were allocated significantly higher values of most examined parameters. Among all tested parameters, logistic regression analysis marked tMN, CB, and iCB as the best predictors with high discrimination accuracy of separation between exposed and unexposed persons. The obtained data encourage us to consider certain cytogenetic parameters as valuable markers for preventive medical screening as the extent of cytogenetic damage reflects cumulative exposure events and possible health consequences related to chronic occupational genotoxic exposure.

Augmented oxidative stress in infertile women with persistent chlamydial infection.

There is established association between oxidative stress, infections of genital tract and fertility. Genital tract infections may provoke increased production of free radicals and generate oxidative stress that can be involved in pathophysiology of a number of reproductive diseases and complications during pregnancy. The aim of this study was to determine connection between oxidative stress and infertility associated with persistent chlamydial infection. Serum samples of infertile women with tubal factor infertility (TFI), women with multiple spontaneous abortions (MSA) and fertile women was screened for C. trachomatis MOMP specific IgG and IgA antibodies and cHSP60 specific igG antibodies using ELISA. The levels of superoxide anion radical, nitric oxide and reduced glutathione were determined spectrophotometricaly. Serum levels of testosterone, luteinizing hormone and follicle stimulating hormone were determined by enzyme-linked fluorescent immunoassay method. Our results showed that persistent infection was more prevalent in TFI than in MSA group, whereas seropositivity was higher in MSA than in TFI group of patients. We also found that superoxide anion was significantly lower, while LH was markedly higher in TFI and MSA group of patients. However, when our results were analyzed according to the serological status of chlamydial infection, we found that parameters of oxidative stress, superoxide anion and index of oxidative stress, defined as relative ratio between superoxide anion and nitrites sum and glutathione ((O2-+NO2-)/GSH) were significantly elevated in infertile patients with persistent chlamydial infection compared to seropositive and seronegative patients. Our findings point to the possible impact of Chlamydia trachomatis infection on prooxidative-antioxidative balance that can influence fertility potential in women with persistent chlamydial infection.

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay).

PURPOSE: In the framework of the 'Realizing the European Network of Biodosimetry' (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one. MATERIALS AND METHODS: Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate. Micronucleus analysis was performed by automated, semi-automated and manual procedures. RESULTS: The dose estimates provided by network laboratories were in good agreement with true administered doses. The most accurate estimates were reported for low dose points (≤ 0.94 Gy). For higher dose points (≥ 2.7 Gy) a larger variation in estimates was observed, though in the second exercise the number of acceptable estimates increased satisfactorily. Higher accuracy was achieved with the semi-automated method. CONCLUSION: The results of the two exercises performed by our network demonstrate that the micronucleus assay is a useful tool for large-scale radiation emergencies, and can be successfully implemented within a large network of laboratories.

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA).

PURPOSE: Two quality controlled inter-laboratory exercises were organized within the EU project 'Realizing the European Network of Biodosimetry (RENEB)' to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network. MATERIALS AND METHODS: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants. RESULTS: The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point. CONCLUSIONS: In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners.

Micronuclei as a marker for medical screening of subjects continuously occupationally exposed to low doses of ionizing radiation.

CONTEXT: Genotoxicity assays are widely employed in human biomonitoring studies to assess genetic damage inflicted by genotoxic agents. OBJECTIVE: Evaluation of micronuclei (MN) as a screening marker of occupational ionizing radiation (IR) exposure. MATERIALS AND METHODS: Using micronucleus test, peripheral blood lymphocytes (PBL) of 402 control and exposed subjects were screened for genetic damage. RESULTS: The mean frequencies of micronucleus test parameters were significantly higher in exposed persons. Increase of micronucleus yield with duration of exposure (DOE) by 0.303MN/year was revealed. DISCUSSION AND CONCLUSION: The obtained data encourage us to consider MN as valuable markers for preventive medical screening of occupationally exposed groups.

A cytogenetic study of hospital workers occupationally exposed to radionuclides in Serbia: premature centromere division as novel biomarker of exposure?

PURPOSE: The health risk of chronic exposure to radionuclides includes changes in the genome (e.g., chromosomal aberrations and micronuclei) that increase chromosomal instability. There are also other phenomena, which seem to appear more frequently in metaphases of exposed persons (such as premature centromere division). The aim of this study was to discover whether or not there is correlation between incidence of named cytogenetic changes in persons occupationally exposed to radionuclides in comparison with unexposed control group, and if significant correlation is determined, can premature centromere division be consider as a biomarker of radiation exposure? METHODS: The exposed group comprised 50 individuals occupationally exposed to radionuclides. The reference control group consisted of 40 unexposed individuals. Chromosomal aberrations, micronuclei and premature centromere division were analyzed according to a standard International Atomic Energy Agency protocol. Statistical analyses were performed using SPSS 17.0 statistics. RESULTS: The means for analyzed cytogenetic changes were significantly higher in the exposed group. Positive correlation between them was found in exposed group. Premature centromere division parameter PCD5-10 was selected as particularly suitable for separating groups (exposed/unexposed). CONCLUSIONS: Identification of other phenomena related to radionuclide exposure, beside well known, may clarify recent problems in radiobiology concerning the biological response to low doses of ionizing radiation and its consequences.

Inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation: comparison of the dicentric and micronucleus assays.

Ionizing radiation can induce a wide range of DNA damage that leads to chromosomal aberrations. Some of those aberrations (dicentrics and micronuclei) are applied in biodosimetry. Biological dosimetry assumes similar radiosensitivity of each donor, but it does not exclude inter-individual variations in radiation susceptibility. Therefore, for biological reasons, it is always challenging to investigate inter-individual variability in response to radiation. For mechanistic reasons, it is also interesting to investigate the correlation between dicentric and micronuclei formation in response to radiation. In this experiment, irradiated blood specimens from 14 healthy male and female donors have been used to evaluate inter-individual variability in response to the genotoxic effects of X-ray radiation, as well as the dose-response relationship and test sensitivity using two endpoints (dicentrics and micronuclei). The results showed similar patterns of cytogenetic biomarker distribution between donors, but differences in the response of some donors at some doses. Data also showed that responses of male donors were better detected using the dicentric test, while for females, micronucleus frequencies were higher in response to the same dose of radiation. No influence of smoking status or age on specific responses was observed. Group variability in response to radiation was evaluated using coefficient of variation for each group of individuals irradiated with the same doses; as the dose increases, group variability becomes substantially lower. Despite sporadic inter-individual variability, trend of radiation-induced changes was similar. Produced calibration curves for both types of damage revealed dicentrics as genetic damage more typical for radiation than micronuclei.