Sister chromatid exchanges in patients with oral submucous fibrosis

The incidence of sister chromatid exchange (SCE) was investigated in the lymphocyte chromosomes of 45 patients with oral submucous fibrosis and 56 age- and sex-matched nonsmoking controls. The frequency of SCE was 9.26 +/- 2.15 in patients with oral submucous fibrosis, which was significantly higher than the mean SCE value of 5.49 +/- 1.24 observed in normal controls. The frequency of SCE in patients with oral submucous fibrosis addicted to the habit of betel with tobacco chewing, "bidi"/cigarette smoking and combined habits of chewing and smoking of tobacco were 8.12 +/- 1.69, 9.43 +/- 1.87, and 10.06 +/- 2.28, respectively. These values were also significantly higher as compared with the SCE values observed in normal controls.     

Sister chromatid exchange in malignant lymphomas

Sister chromatid exchange (SCE) was evaluated in peripheral lymphocytes from 20 untreated patients with malignant lymphomas: 6 with Hodgkin's disease (HD), 14 with non-Hodgkin lymphoma (NHL), and 5 with lymphadenitis. The mean SCE frequency (+/- SE) was: 11.2 +/- 0.6, 11.0 +/- 0.6, and 7.2 +/- 0.3 for HD, NHL, and lymphadenitis patients, respectively, and 8.7 +/- 0.2 for the control group. No differences in SCE score were observed in HD and NHL. These results allowed us to consider both groups (HD and NHL) as a single neoplastic population (mean +/- SE, 11.0 +/- 0.4). No significant differences were found between the lymphadenitis and control groups. On the other hand, significantly higher SCE scores were seen in neoplastic populations than in the control and lymphadenitis groups (p less than 0.001 and p less than 0.01, respectively). When SCE was compared by chromosome number and group between neoplastic patients and controls, a higher SCE frequency was observed in chromosomes #1, #2, #3, and B, C + X, E, F chromosome groups than in controls. SCE levels were significantly higher in lymphoma patients in all chromosome numbers and groups mentioned than in patients with lymphadenitis. It is suggested that the high SCE rate in the malignant lymphoma population is possibly related to an increased chromosomal instability.     

The effect of tobacco smoking on the frequency of sister chromatid exchanges in human lymphocyte chromosomes

The incidence of sister chromatid exchange (SCE) was investigated in the lymphocyte chromosomes of 24 bidi smokers, 18 cigarette smokers, and 20 normal nonsmoking controls. Bidi and cigarette smokers had a mean SCE per cell of 10.12 +/- 2.41 and 8.15 +/- 1.62, respectively, which were significantly higher than the mean value of 5.48 +/- 1.29 found in controls. Higher frequencies of SCE were also observed in individuals who smoked more than ten bidis or cigarettes per day, compared with people who smoked less than ten bidis or cigarettes per day, respectively. Individuals who smoked bidis or cigarettes for more than 10 years also showed an increased frequency of SCE as compared with those who smoked bidis or cigarettes for less than 10 years.     

Sister chromatid exchanges in the lymphocytes of control women, pregnant women, and women taking oral contraceptives: effects of cell culture temperature

The incidence of sister chromatid exchange (SCE) was investigated in the lymphocytes of control women, pregnant women, and women using oral contraceptives after culture at 37 degrees C and 40 degrees C. At 37 degrees C, the mean frequency of SCE (MEAN +/- S.E.) was found to be 7.91 +/- 0.30 in pregnant women and 8.53 +/- 0.29 in oral contraceptive users which were significantly higher than the SCE value of 5.56 +/- 0.21 found in control women. Increase in growth temperature to 40 degrees C elevated the SCE frequency to 11.86 +/- 0.44 in pregnant women, 12.76 +/- 0.46 in oral contraceptive users and 7.24 +/- 0.26 in control women. These data indicate that there is a differential induction of SCEs following increased cell culture temperature in the lymphocytes of pregnant women and oral contraceptive users, compared with control women.     

Increased spontaneous and mitomycin C-induced sister chromatid exchanges in patients with cancer of the cervix uteri, with special reference to stage of cancer

The frequencies of spontaneous and mitomycin C (MMC)-induced sister chromatid exchange (SCE) were examined in 35 patients with cancer of the cervix uteri (stage 0, eight cases; stage I, nine cases; stage II, nine cases, and stage III, nine cases) before they had undergone cancer treatment, as well as in seven patients with uterine myoma and 18 healthy women as controls. The frequency of SCE was analyzed in reference to the stage of cancer in the cancer group and in reference to chromosome group in the cancer and normal groups. The frequencies of spontaneous and MMC-induced SCE in the cancer group were 10.0 +/- 1.8 and 20.7 +/- 2.6, respectively, and both were significantly higher than in the myoma (8.1 +/- 0.8 and 17.6 +/- 1.8) and normal (7.6 +/- 0.8 and 17.6 +/- 2.3) groups. Furthermore, the frequency of SCE in the cancer group increased with cancer stage. All chromosome groups contributed equally to the increase in SCE in the cancer group. These results indicate that an increase in the frequency of SCE in patients with cervical cancer is related to the presence of cancer, but is not related to a predisposition to cancer.     

Sister chromatid exchanges in leukemic patients

Sister chromatid exchange (SCE) was studied in PHA-stimulated peripheral blood lymphocytes from 36 newly diagnosed and untreated leukemic patients: 16 with acute lymphoblastic leukemia (ALL), 10 with acute nonlymphocytic leukemia (ANLL), and 10 with chronic myelocytic leukemia (CML). The metaphases analyzed show no chromosomal abnormalities. The mean SCE frequency (mean +/- SE) for each group of patients was: 6.8 +/- 0.4, 6.6 +/- 0.3, and 7.0 +/- 0.6 per mitosis, respectively, which was significantly lower than the mean SCE score for 30 controls (8.7 +/- 0.2). No differences in SCE score among ALL, ANLL, and CML and a similar SCE frequency by chromosome number and group allowed consolidation of all the cases into a single group of 36 leukemic patients (6.8 +/- 0.3). When the frequency of SCE was compared by chromosome number and group between the leukemic patients with the control group, a significant decrease in SCE frequency was observed due to a low SCE score in almost all the complements, except chromosome #1. It is suggested that the low SCE rate is related to the leukemic process itself.     

Sister chromatid exchanges and ion release in patients wearing fracture fixation devices

The quantification of sister chromatid exchange (SCE) during mitosis is a useful index for evaluating genotoxic effects in subjects occupationally or incidentally exposed to potentially toxic substances. The authors investigated the hypothesis that ions released by corrosion from prosthetic components of fracture fixation devices are associated with change in SCE incidence. In the present study, ten patients with implants were examined, and fifteen subjects with no implants were used as controls. SCE and high frequency cell (HFC) numbers were evaluated in circulating lymphocytes. In addition, nickel (Ni) and chromium (Cr) ion values in the serum were measured because, after iron, these metals are major components of stainless steel. A significant increase in SCE numbers was observed in patients compared to the control population (4.9 +/- 1.3 vs. 3.5 +/- 1.4). Ni concentration was 1.71 +/- 1.49 ng/mL in patients and 0.72 +/- 0.52 ng/mL in control subjects; Cr concentration was, respectively, 1.01 +/- 0.77 ng/mL and 0.19 +/- 0. 27 ng/mL. The increase of serum Cr and Ni was statistically significant. No correlation was found between the increased Cr concentrations and SCE number while Cr ion levels were found to be significantly correlated to HFC. An inverse correlation between Ni level and SCE numbers was observed. Our findings suggest that Cr release by stainless steel implants could have a genotoxic effect; thus it would be useful to carefully monitor implanted subjects with regard to serum ion dosage, SCE analysis, and HFC evaluation. In any case, it would be appropriate to remove the implant when fracture fixation is reached.     

Sister chromatid exchange in dyskeratosis congenita lymphocytes.

Sister chromatid exchange (SCE) frequency in chromosomes from lymphocytes of a patient with dyskeratosis congenita was 12-2 per mitosis. Our 33 normal controls had a mean of 5-4 SCE per mitosis and 5 patients with Fanconi's anaemia averaged 7-6 SCE per mitosis. The rate of chromosome breakage was only 0-5% in the dyskeratosis congenita patient and 0 to 2-5% in controls, while the Fanconi's anaemia patients showed higher values.     

Relationship of oral cancer with age, sex, site distribution and habits

Many studies are carried out regarding age incidence, tobacco smoking and sites of oral cancer, but in Gujarat tobacco chewing in form of Gutkha is more common than smoking and start during preteen years. Tobacco chewing causing chronic inflammation, submucous fibrosis and oral cancer. This study was conducted on 504 patients to find out if there is increasing incidence of oral cancer in lower age group and its relation with sex as well which site was commonly affected. There was statistically significant increase in oral cancer in lower age group, and anatomically anterior part of oral cavity showed involvement in 61.32% of cases. Though males were affected more but female cases were 25%. So tobacco chewing has got detrimental effect on oral cavity.     

Fibroblast cultures of patients with basal cell epithelioma exhibit a normal sensitivity to the genotoxic effect of ultraviolet irradiation.

Fibroblast cultures of 16 basal cell epithelioma (basalioma, BCE) patients with an unusually young age at onset of disease (29-51 years; 42.5 +/- 7.04), and healthy normal controls (27-55 years; 40.73 +/- 9.52) were studied for chromosome instability induced by ultraviolet rays (UV). We used an UV source that emitted predominantly UV-A and UV-B at an intensity of 375 J/m2 and evaluated the induction of micronuclei (MN) and sister chromatid exchange (SCE). Young basalioma patients and normal controls showed no significant differences in MN and SCE frequencies, neither with respect to spontaneous nor to UV-induced values (MN spontaneous: 10.80 +/- 5.65 vs. 11.32 +/- 8.21; UV-induced increase: 7.36 +/- 4.40 vs. 9.93 +/- 7.55; SCE spontaneous: 10.28 +/- 1.61 vs. 10.72 +/- 1.09; UV-induced increase: 7.30 +/- 2.19 vs. 7.55 +/- 2.14). We conclude from these data that an enhanced UV sensitivity as observed in cells from patients with cutaneous malignant melanoma and xeroderma pigmentosum is not a constitutive risk factor in basalioma patients.     

Sister chromatid exchanges in peripheral lymphocytes from women with carcinoma of the uterine cervix

Sister chromatid exchanges (SCE) are reciprocal exchanges between sister chromatids. It has been reported that in patients with cervical cancer, the frequency of SCE in peripheral lymphocytes is significantly higher than that in normal individuals; however, other studies have shown no significant difference. The aim of this unmatched case-control study was to compare the mean number of SCE per metaphase in lymphocytes from women with and without carcinoma of the cervix uteri. The SCE specimens were prepared by the fluorescence plus giemsa technique in peripheral lymphocytes from 28 women with carcinoma of cervix uteri and 28 controls. The mean number of SCE per metaphase in women with carcinoma of cervix uteri (7.80 +/- 1.05) was higher than the control group (6.98 +/- 1.13) (P < 0.05; t-test). This study had a statistical power of 0.80 and an alpha value of 0.05. This finding suggests that an increased number of SCE in peripheral lymphocytes is associated with cervical cancer. We consider that the lack of reported association of SCE and cervical cancer might be attributed to the none determination of the statistical power and sample size.     

I. The modulatory effect in genotoxic responses due to age and duration of PHT-therapy in epileptic patients

Sister chromatid exchange (SCE) frequency has been studied from the peripheral blood lymphocyte cultures of 42 epileptic patients on the anticonvulsant drug phenytoin (PHT) for 3 months and their follow-up (6 and 9 months), of 33 epileptics who had not started therapy (PHT-untreated), and of 40 normal healthy controls, all in the same age group, i.e., 10-30 years. PHT-treated epileptic patients at all three durations of therapy (3, 6, and 9 months) showed higher SCE frequency (P < 0.001) than healthy controls and PHT-untreated patients. There was no significant difference in SCE frequency between control and PHT-untreated patients, suggesting that disease is not associated with an increased frequency of SCEs. The frequency of SCEs seems to be influenced by an age factor, when older treated patients (21-30 years) showed higher SCE frequencies at 3 and 6 months (P < 0.001) and 9 months (P < 0.05) than the younger age group (10-20 years). SCE frequency increased linearly with the duration of therapy, i.e., from 3 months to 9 months. No correlation was found between SCE frequency and sex with respect to controls, PHT-untreated, and PHT-treated subjects. In conclusion, the modulating effect on SCE frequencies elicited by age and duration of therapy has been clearly demonstrated by SCE mean analysis. Teratogenesis Carcinog. Mutagen. 21:135-149, 2001.     

Sister chromatid exchange in normal and Ph1-positive leukemic cells after mitomycin-C treatment in vitro

The sister chromatid exchange (SCE) frequency was investigated in normal bone marrow and Ph1-positive cells of chronic myelocytic leukemia (CML) patients with and without mitomycin-C (MMC) treatment in vitro. Even though the spontaneous SCE frequency was found to be significantly lower in CML cells, the absolute SCE values after MMC treatment did not differ between leukemic and normal cells, and this seems to indicate an equilization of SCE rates. However, the fact that leukemic cells with lower spontaneous SCE rates need a further increase of SCE to reach values equal to those of normal cells might indicate a somewhat higher susceptibility of leukemic cells to DNA damage by MMC. This interpretation appears to be confirmed by the fact that the inhibition of cellular proliferation at higher MMC doses considerably reduced the number of leukemic cells that was able to divide twice during a given culture time.     

Sister chromatid exchange: Variation by age,sex, smoking,and breast cancer status

Variation in sister chromatid exchange (SCE) frequency in lymphocytes of 125 persons was compared using a multivariate general linear model. The study was performed to determine whether SCE frequency differs with respect to age, sex, smoking, and breast cancer status. Study subjects were divided into: members of two branches of families having an excess of cancer (primarily breast) including a brother and sister in one family who developed nonbreast malignancies within 1 yr of the study; women in both families successfully treated for breast cancer (all at least 5 yr posttreatment); and women from the general population with confirmed breast cancer.Controls consisted of spouses who married into the high-risk kindreds, hospital personnel, and others (primarily tradesmen without history of occupational exposure). Results show that: (1) Women with active breast cancer have a significantly higher mean SCE frequency than control women or women greater than 5 yr posttreatment for breast cancer; (2) Cigarette smokers show a significantly higher number of SCEs than was observed in nonsmokers; (3) The increase in SCE level in smokers is dose-related to exposure as measured by cumulative pack-years; (4) SCE values in both high-risk families are not significantly different from controls; (5) Neither the age nor sex of the individual affects SCE frequency; and (6) The observed distribution of exchanges agrees with that expected based on the proportion of the genome represented by each chromosome group.     

Chromosomal aberration,micronucleus and Comet assays on peripheral blood lymphocytes of leprosy patients undergoing multidrug treatment

To evaluate the genetic damage in leprosy patients, we carried out the alkaline Comet assay and chromosomal aberration (CA) and micronucleus (MN) tests in peripheral blood lymphocytes of 50 leprosy patients receiving multidrug treatment (MDT) and 50 healthy individuals. The Comet assay showed statistically higher mean values for length to width ratios of DNA mass (P < 0.01) and for mean frequencies of tailed cells (P < 0.001) in cells of leprosy patients than in those of controls. Similarly, the mean frequencies of micronucleated cells (per 1000 cytochalasin B-induced binucleated cells) were significantly greater (P < 0.001) in leprosy patients (19.92 +/- 2.564) than in controls (1.6 +/- 0.231). A statistically significant 10-fold increase in the frequency of CAs (11.16 +/- 0.411) was observed in leprosy patients compared with controls (1.28 +/- 0.242). In multiple regression analyses, when patients and controls were considered together, disease factor alone significantly influenced the genotoxicity markers. In the control group, age and alcohol consumption significantly influenced MN and length to width ratios and CA frequency, respectively. However, in MDT-treated leprosy patients none of the other confounding factors (sex, age, smoking and alcohol drinking) significantly affected the extent of genetic damage.     

Cell-Mediated Immunity to Human Oral Carcinoma, and Cross Reactivity to Patients with Oral Leukoplakia Demonstrated by the Leukocyte Migration Test

Tissue extracts from 18 oral carcinomas were tested in the leukocytes migration capillary technique(LMCT) against autologous leukocytes and against leukocytes of healthy matched controls. The normal range was defined as the mean migration index (MI) of the leukocytes of the normal control ±2SD. Three carcinoma patients showed significant inhibition and one was on the lower borderline on the normal range. None showed stimulation. When leukocytes of leukoplakia patients were tested against normal intesttine and two homologous oral carcinoma extracts, significantly different MI's were found between carcinoma and normal intensive. The finding are compatible with a state of tissue-specific, cellular hypersensitivity against antigenic components present in oral leukoplakia and in oral carcinoma, and is possibly common between the two.     

Sister chromatid exchange analysis in the Prader-Labhart-Willi syndrome

The number of sister chromatid exchanges (SCE) and cell kinetics in lymphocytes were investigated from 16 Prader-Labhart-Willi syndrome (PLWS) patients [8 with 15q12 deletion (4 females, 4 males; mean age = 12.9y with age range of 0.3 to 24y), and 8 non-deletion (2 females, 6 males; means age = 16.8y with age range of 5 to 26y)], 18 parents of PLWS patients and age-matched control individuals. The average SCE frequency and standard deviation in PLWS patients with and without the chromosome 15 deletion was 6.6 +/- 1.3 and 6.2 +/- 0.8, respectively. Therefore no significant difference in SCE frequency or replicative index was found between the two PLWS subgroups. There was also no significant difference in SCE frequency or replicative index between the 16 PLWS patients and age-matched control subjects. The average SCE frequency and standard deviation in 8 fathers who were previously identified to have donated the chromosome 15 with the deletion in the child was 7.5 +/- 1.2, which was not significantly different from 8.5 +/- 2.0 seen in age-matched control subjects. There was also no significant difference in the SCE frequency or replicative index of 18 parents of PLWS patients with and without the chromosome 15 deletion when compared with age-matched control subjects.     

Sister chromatid exchanges in lymphocytes of patients with oral carcinoma

Sister chromatid exchanges (SCEs) were studied in cultured peripheral lymphocytes of 22 untreated patients with squamous cell carcinoma of the oral cavity and 29 age- and sex-matched controls. The SCE rate in cancer patients was not significantly higher compared with that found in controls, but there was a significant correlation between the SCE rate in lymphocytes of the cancer patients and the size of the primary tumor.     

Sister chromatid exchange analysis in familial groups of malignant melanoma patients

Sister chromatid exchange (SCE) analysis was carried out on peripheral blood lymphocytes of 20 familial malignant melanoma (FMM) and 39 sporadic malignant melanoma (SMM) untreated patients, belonging to 10 and 39 families, respectively. The study was extended to 39 unaffected close relatives of FMM patients, to 187 unaffected close relatives of SMM patients, and to 20 unaffected unrelated individuals (control group), all examined under the same conditions. The mean SCE rates/cell were significantly higher in MM families than in the control group, and in melanoma patients than in their close relatives. The mean SCE levels of FMM and SMM patients, (8.4 +/- 0.8 and 8.0 +/- 0.3, respectively) were similar, and so were the distributions of individuals in classes of increasing SCE values (with a modal value at 7-8 SCEs/cell). The mean SCE levels of close relatives of FMM and SMM patients were also similar (5.4 +/- 0.2 and 5.4 +/- 0.1, respectively, with a modal value at 4-5 SCEs/cell), and slightly higher than in the control group (4.7 +/- 0.2 SCEs/cell). More than 7 SCEs/cell were observed in the majority (41 of 59) of FMM or SMM patients, in a smaller fraction (25 of 227) unaffected relatives, and in none of 20 unrelated unaffected individuals. These observations favor the hypothesis that higher SCE levels may be an expression of constitutional lesions predisposing to this neoplastic disease.     

Investigation of the occurrence of torque tenovirus in malignant and potentially malignant disorders associated with human papillomavirus

In a previous pilot study, a significantly poorer outcome of laryngeal cancer was found in patients co‐infected with human papillomavirus (HPV) and genogroup 1 torque tenovirus (TTV). The present study aimed to collect data on the overall prevalence of TTVs on the prevalence of genogroup 1 TTV in two other malignancies associated with HPV, oral squamous cell cancer and cervical cancer, and in oral and cervical premalignant lesions (oral lichen planus, oral leukoplakia, cervical atypia). Oral samples from all patients were accompanied with a sample from the healthy mucosa. The overall prevalence of TTV was significantly higher both in oral squamous cell cancer and cervical cancer compared with other patient groups or with the respective controls. The prevalence of genogroup 1 TTV was significantly higher in lesions of oral squamous cell cancer and oral lichen planus, but not in lesions of oral leukoplakia (24.6%, 10.1%, and 4.5%, respectively), compared with the prevalence in the oral cavity of controls (1.4%). Co‐infection rates with genogroup 1 TTV and HPV were significantly higher in oral squamous cell cancer than in controls, oral lichen planus or oral leukoplakia patients (12.3%, 0.0%, 6.7%, and 4.5%, respectively). The prevalence of genogroup 1 TTV in all cervical samples were comparable. These data suggest that genogroup 1 TTV may be associated specifically with some head and neck mucosal disorders, but disproves a (co)carcinogenic role in oral cancer or cervical cancer as well as an association with HPV or with malignancies associated with HPV. J. Med. Virol. 81:1975–1981, 2009. © 2009 Wiley‐Liss, Inc.