Search

Background: Metal alloys utilized in the management of jaw fractures may exert genotoxic effects. Our purpose was to compare the genotoxicity of intermaxillary fixation devices containing nickel and chromium to that of titanium miniplates utilized in treatment of jaw fractures through the analysis of sister chromatid exchange., Methods: In this prospective study, in a total of 28 non-smoker patients (10 females, 18 males; mean age 33.43±10.76; range 15 to 60 years) with jaw fractures, 14 were treated with intermaxillary fixation by administration of nickel-chromium wire and arch bar and 14 with titanium miniplates to investigate the genotoxicity of different metal alloys. The outcome variable was the frequency of sister chromatide exchange in peripheral lymphoctyes, determined through the analysis of venous blood samples obtained preoperatively and 4 to 6 weeks postoperatively., Results: The frequency of the average sister chromatid exchange was found to be significantly higher in patients treated with the nickel-chromium intermaxillary fixation devices than those treated by titanium miniplates (1.29±0.29 vs. 0.46±0.39, p<0.001)., Conclusion: Although titanium miniplate osteosynthesis is an invasive technique in comparison with the nickel-chromium-containing intermaxillary fixation devices, titanium seems to exert less genotoxic effect than the nickel-chromium alloy. However, this finding should be supported in clinical studies with a larger sampling size.

Objective: The purpose of this study was to determine the genetic instability of peripheral blood lymphocytes from patients diagnosed with oral lichen planus (OLP) by investigation of frequencies of micronuclei (MN) and sister chromatid exchange (SCE)., Materials and Methods: A total of 22 newly diagnosed and untreated patients with OLP of same severity scores and twenty healthy controls participated in this study. They were all non-smokers with no previous history or family history of cancer. The periodontal status, flow rate and buffering capacity of whole mouth saliva were recorded. SCE and MN analyses were performed on peripheral blood lymphocytes of OLP patients and healthy controls., Results: The frequencies of MN (50.00 +/- 22.36) and SCE (6.89 +/- 1.48) in OLP patients were found to be significantly elevated compared with that in normal individuals (25.20 +/- 9.52 and 5.93 +/- 1.31; z = 3.946, P = 0.0001; z = 2.346, P = 0.019). There were no significant differences in the MN frequency and SCE between the two subgroups with reticular or erosive types of OLP., Conclusion: These pilot data indicate an increased genomic instability in peripheral blood lymphocytes of a cohort of Turkish patients diagnosed with oral lichen planus as compared with that of healthy individuals. As patients with OLP may have an increased or potential risk for oral malignancy, these assays could be used in translational research to monitor beneficial effects of interventions and long-term prognosis.

Long-term use of Cyclosporin A (CsA) and Tacrolimus is known to yield serious untoward side effects including nephrotoxicity, neurotoxicity, and malignant tumor formation. Sister chromatid exchange (SCE) is used to assess the genotoxic potential of various agents. A total of 37 postrenal transplant patients receiving either CsA (n = 20) or Tacrolimus (n = 17) were included in this study. The genotoxic effects of CsA and Tacrolimus were assessed by determination of SCE frequency. In patients receiving CsA, SCE frequency was increased significantly compared to that in the control group (p = 0.001), whereas Tacrolimus did not yield such a significant change (p = 0.801). SCE frequency was not correlated with drug dosage (p > 0.05). Our results indicate that the use of CsA, but not Tacrolimus 506, is associated with an increased genotoxic effect in postrenal transplant patients.

In this study, we aimed to evaluate genotoxicity by sister chromatid exchange frequency in the peripheral lymphocytes of patients with myelodysplastic syndrome (MDS). The study population consisted of 16 patients (females/males:6/10; mean age: 61.68 +/- 13.08 years) diagnosed with "refractory anemia" according to FAB classification. The results were compared with an age- and sex-matched control group. The sister chromatid exchange frequency in the study group was found to be significantly higher than the control group (8.3 +/- 11 vs. 6.83 +/- 1.07, P=0.0046). We suggest that increased DNA damage, which is revealed by the increased sister chromatid exchange in the present study may play a role in the etiopathogenesis of MDS.

Objective: The object of this study was to investigate the genotoxic effect of acute overexposure to combustion products originating from coal or wood stoves in patients presenting with acute carbon monoxide intoxication., Study Design: In a prospective study, we analyzed the frequency of sister chromatid exchange and the carboxyhemoglobin concentration in 20 consecutive patients without a history of smoking or drug use who had been treated in the Emergency Care Unit of Istanbul Medical Faculty due to acute carbon monoxide intoxication. All of these cases were domestic accidents due to dysfunctioning coal or wood stoves. The results were compared with a control group of 20 nonsmoking, nondrug-using healthy individuals matched for age, sex, and absence of other chemical exposure., Results: The mean sister chromatid exchange frequency per metaphase was significantly higher in the study group compared to the control group: 8.11 +/- 2.39 vs. 6.33 +/- 1.60 (p = 0.008). We found that there was no positive correlation between the blood carboxyhemoglobin concentration and sister chromatid exchange frequency., Conclusions: These results suggest that acute exposure to combustion products of wood or coal is genotoxic to DNA. Potential causes of genotoxicity include known mutagenic compounds present in coal or wood smoke and ash, oxygen radicals formed during combustion, as well as hypoxic and reperfusion injury mechanisms initiated by carbon monoxide intoxication. Additional studies on separate carbon monoxide exposure from smoke and ash are needed to understand individual genotoxic contributions and mechanisms.

Chronic lymphocytic leukemia (CLL) is characterised by the clonal proliferation and accumulation of neoplastic B-lymphocytes. The median age of the patients is 65 years, and more men than women are affected. The overwhelming majority of CLLs are of B-cell origin. Chromosomal aberrations have been detected in more than 50% of the B-cells obtained from peripheral blood samples after appropriate stimulation with polyclonal B-cell mitogens. The analysis of sister chromatid exchange is a cytogenetic technique used to show DNA damage due to an exchange of DNA fragments between sister chromatids. In this study, lymphocytes from 22 patients with CLL-B (7 female, 15 male; mean age 64.09 +/- 7.56 years) were stimulated by a B-cell mitogen (TPA) and BrdU added at the 24 h of the culture. Metaphase chromosomes were stained with a fluorescence plus Giemsa technique after a standard harvest procedure. The frequency of sister chromatid exchange was found to be increased significantly P =.02) in patients with CLL-B (8.24 +/- 1.36 per metaphase) compared to controls (7.25 +/- 1.42 per metaphase). We conclude that the increased frequency of sister chromatid exchange in chronic lymphocytic leukemia after stimulation with a B-cell mitogen (TPA) may reflect DNA instability and defective DNA repair in these patients.

We analyzed the induction of sister chromatid exchange (SCE) by cyclosporin A (CsA) as a marker of genotoxic potential. In 30 patients undergoing renal transplantation, SCE induction was tested before the introduction of CsA and 3 months later. We found that SCE frequency increased significantly at the end of 3 months. To our knowledge, this is the first study demonstrating in vivo induction of SCE by CsA in humans. We conclude that CsA has a genotoxic potential on human lymphocytes.