Sister chromatid exchange rate from pleural fluid cells in patients with malignant mesothelioma

Cytogenetic outcomes of adjuvant chemotherapy in non-target cells of breast cancer patients

Spontaneous and chemotherapy-induced sister chromatid exchanges (SCES) and lymphocyte proliferation rate index (PRI) in cultured peripheral lymphocytes were evaluated in 30 patients with diagnosed breast cancer before and after adjuvant chemotherapy and in 30 healthy women with no known familial history of breast cancer. Before chemotherapy, the breast cancer patients had a significantly increased background level of SCE, and lowered PRI as compared with the healthy women. Marked inter-individual variations were observed in both endpoints among the patients. Significantly elevated frequency of SCE and depressed PRI were recorded in blood samples collected after the first cycle of chemotherapy, with high inter-individual variations in the responses to the chemotherapy. FAC (5-fluorouracil, adriamycin and cyclophosphamide) protocol was the most genotoxic of the protocols studied, but also AC (adriamycin, cyclophosphamide) and CMF (cyclophosphamide, methotrexate and 5-fluorouracil) clearly increased SCE. All protocols significantly retarded lymphocyte proliferation in vitro. Our findings indicate that both SCE and PRI may serve as sensitive biomarkers for the routine detection of critical lesions produced by the administration of antineoplastic drugs in the clinical setting, as well as for possible screening of high-risk individuals among patients who have successfully completed chemotherapy. Human & Experimental Toxicology (2007) 26 , 391—399

Antineoplastic Drugs as a Potential Risk Factor in Occupational Settings: Mechanisms of Action at the Cell Level, Genotoxic Effects, and Their Detection Using Different Biomarkers

U članku je prikazana osnovna podjela antineoplastičnih lijekova prema mehanizmima djelovanja na razini stanice. Objašnjeni su mehanizmi genotoksičnosti najvažnijih vrsta lijekova koji se primjenjuju u okviru uobičajenih protokola za liječenje zloćudnih novotvorina. Navedena je važeća klasifikacija antineoplastika prema kancerogenom potencijalu, podaci o mutagenom potencijalu te je prikazana njihova podjela u skladu s anatomsko-terapijsko-kemijskim sustavom klasifikacije. Sustavno su prikazani najvažniji rezultati svjetskih i hrvatskih istraživanja na populacijama radnika izloženih antineoplasticima, provedenih u razdoblju 1980.-2009. s pomoću četiri najčešće primjenjivane metode: analize izmjena sestrinskih kromatida, analize kromosomskih aberacija, mikronukleus-testa i komet-testa. Objašnjena su osnovna načela navedenih metoda te raspravljene njihove prednosti i nedostaci. Biološki pokazatelji daju važne podatke o individualnoj osjetljivosti profesionalno izloženih ispitanika koji mogu poslužiti unaprjeđenju postojećih uvjeta rada i upravljanju rizicima pri izloženosti genotoksičnim agensima. Na osnovi prednosti i nedostataka citogenetičkih metoda zaključeno je da je mikronukleus-test, koji podjednako uspješno dokazuje klastogene i aneugene učinke, jedna od najboljih metoda dostupnih za otkrivanje štetnih djelovanja antineoplastičnih lijekova koji su u aktivnoj primjeni.

The genotoxic risk in health care workers occupationally exposed to cytotoxic drugs--a comprehensive evaluation by the SCE assay

Present study aimed at an integral assessment of sister chromatid exchange (SCE) frequencies in the health care workers occupationally exposed to cytostatics. The results of 500 individual analyses were evaluated. Drug handling practice was investigated in parallel and the results showed that cytostatics are mostly prepared outside hospital pharmacy (98%) and mainly handled by nurses (96%). Mean frequency of SCE was 5.63 +/- 2.28, while HFC represented 9.65% of the cells analysed. Both values were higher compared to previously established control values for Croatian population. The duration of exposure, profession, age, gender, smoking habit, medical exposures, and simultaneous exposure to other occupational mutagens significantly contributed to SCE and HFC values. The usefulness both biomarkers in the assessment of cytogenetic damage is confirmed. Since current practice in Croatian hospitals does not include regular monitoring of workplaces, to ensure maximal occupational safety, a surveillance on exposed health care workers, including periodic biomonitoring, is recommended.

Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos

Exposure to asbestos minerals has been associated with a wide variety of adverse health effects including lung cancer, pleural mesothelioma, and cancer of other organs. Many of the regions of Turkey have asbestos deposits. People in Doğanli village - one of these regions - have been environmentally exposed to chrysotile asbestos since they were born. In this study the effects of asbestos on micronucleus (MN) frequencies of inhabitants exposed to chrysotile asbestos have been examined. Thirty subjects who had been environmentally exposed to chrysotile asbestos and living in Doğanli village, and 25 controls were studied to assess the MN frequency. The control group was selected from healthy individuals with no exposure to asbestos and living in similar geographic conditions to Doğanli village. Peripheral blood samples were collected from each subject and cultured for MN assay. Cytochalasin-B was added to lymphocyte cultures for evaluation of MN in binucleated (BN) cells. The differences between those exposed to chrysotile asbestos and controls were not statistically significant in terms of BN cells with MN (p > 0.05). There was not a significant relationship between MN frequencies and age, sex, smoking, both in chrysotile asbestos-exposed subjects and in controls (p > 0.05). Although the detection of calcified pleural plaques found in the inhabitants has indicated environmental exposure to chrysotile asbestos, our results show that chrysotile asbestos was not an inducer of MN in subjects exposed to chrysotile asbestos.

Preliminary study on DNA damage in non breast-fed infants

BACKGROUND

There are many advantages of human milk for infants, including protection against cancer development and the advantages have been emphasized in several studies. In this study, infants fed by human milk has been compared with those fed by cow's milk concerning DNA damage.

METHODS

The level of genetic damage in the peripheral blood lymphocytes of infants who were fed mainly by cow's milk and breast milk has been studied by sister chromatid exchange (SCE) analysis, which is a sensitive measurement of chromosomal damage. Each group consisted of 30 infants, whose ages ranged from 9 to 12 months.

RESULTS

A significant increase (P < 0.0001) was found in the frequencies of SCE of infants not breast-fed (n = 30, mean SCE/cell +/- SD: 8.66 +/- 1.15) compared to those who were breast-fed (n = 30, mean SCE/cell +/- SD: 4.93 +/- 0.82).

CONCLUSION

To our knowledge, there has been no published study investigating SCE ratio regarding DNA damage in infants not breast-fed. Molecular mechanism of DNA damage caused by the absence of human milk protection is a subject of future investigations.

Sister-chromatid exchange frequencies in postmenopausal hormone replacement patients

Our objective was to evaluate the frequency of sister-chromatid exchange (SCE) during hormone replacement therapy in postmenopausal women. Thirty-four asymptomatic postmenopausal women with a minimum 12 months since last menstrual period and surgical menopausal women were included in the study. Seventeen patients who were in spontaneous menopause were administered conjugated estrogen and medroxyprogesterone acetate (group A), and the others who were in surgical menopause were given 17beta-estradiol only (group B). Peripheral lymphocytes were obtained at the beginning and at the end of the third month of therapy. The mean age of the patients was 50. 67+/-4.79. There were statistically significant differences in terms of SCE frequencies between pre- and posttreatment levels of both groups (p<0.001 and p=0.003, respectively). It is likely that estrogens with or without progesterone have an effect in increased SCE frequency and this issue may be an evidence for the increased potential for malignancies.