Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers.

INTRODUCTION: Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). METHODS: The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. RESULTS: In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). CONCLUSIONS: This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

Increased salivary level of 8-hydroxydeoxyguanosine is a marker of premature oxidative mitochondrial DNA damage in gingival tissue of patients with periodontitis.

INTRODUCTION: Oxidative stress may contribute to the pathogenesis of periodontitis. However, the detailed molecular mechanism remains unclear. Both 8-hydroxydeoxyguanosine (8-OHdG) and mitochondrial DNA (mtDNA) deletion have been reported as early oxidative DNA damage markers. In this study, 8-OHdG levels in saliva and mtDNA deletions in gingival tissue of patients with chronic periodontitis (CP) were evaluated. MATERIALS AND METHODS: Gingival tissue and whole saliva samples were collected from 32 patients with CP and 32 healthy control subjects. To determine the clinical condition of each subject, the plaque index, gingival index, clinical attachment level (CAL), and probing depth (PD) were measured. Using the ELISA and polymerase chain reaction methods, the salivary 8-OHdG levels and the 7.4-kbp and 5-kbp mtDNA deletions were examined. RESULTS: The 5-kbp mtDNA deletion was detected in 20 of the 32 periodontitis patients (62.5%), but was not detected in the healthy controls. The mean value of 8-OHdG in the saliva of the periodontitis patients with deleted mtDNA was significantly higher than in the patients with non-deleted mtDNA (p<0.01). Also, significant correlation was found between the occurrence of the 5-kbp mtDNA deletion and salivary 8-OHdG levels (p<0.01). Similar correlations were detected between salivary 8-OHdG levels and age, PD, and CAL (p<0.01, p<0.05). CONCLUSION: Increased oxidative stress may lead to premature oxidative DNA damage in the gingival tissue of periodontitis patients and the salivary 8-OHdG level may signify premature oxidative mtDNA damage in diseased gingival tissue.

Primary hypogonadism, partial alopecia, and Mullerian hypoplasia: report of a third family and review.

Two sisters presented with partial alopecia, primary hypergonadotropic hypogonadism and Mullerian hypoplasia associated with mild mental retardation, microcephaly, flat occiput, sparse eyebrows, absence of breast tissue, absent ovaries, mild-moderate dorsal kyphosis, thin upper lip and unilateral sensorioneural deafness in one of them. They were the product of a Turkish consanguineous marriage. The clinical course for our patients is similar to two families reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622] and Megarbane et al. [Megarbane et al. (2003) Am J Med Genet Part A 119A:214-217]. This report supports the literature by proposing an autosomal recessive syndrome which was firstly reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622]. This condition may be due to a founder mutation.

Adult height in Turkish patients with Turner syndrome without growth hormone treatment.

Spontaneous adult height (AH) in Turner syndrome (TS) varies among populations. Population-specific AH data is essential to assess the efficacy of growth-promoting therapies in TS. A multicenter study was performed to establish AH of nongrowth hormone (GH)-treated Turkish patients with TS. One hundred ten patients with TS (diagnosed by karyotype) who reached AH (no growth in the previous year, or bone age > 15 years) without receiving GH treatment were included in the study. The average AH was found to be 141.6 +/- 7.0 cm at the age of 22.9 +/- 6.2 years, which is 18.4 cm below the population average and 16.4 cm below the patients' mid-parental heights. Bone age at start of estrogen replacement was 12.3 +/- 1.3 year. Karyotype distribution of the patients was 45X (43%), 45X/46XX (16%), 45X/46Xi (12%), 45XiXq (10%) and others (19%). When the patients were evaluated according to their karyotype as 45X and non-45X, no significant difference in AH was observed (142.4 +/- 6.9 cm vs 140.9 +/- 7.1 cm, respectively). Adult height of non-GH-treated Turkish TS patients obtained in this study was comparable to that of other Mediterranean populations, but shorter than that of Northern European patients. Karyotype does not seem to affect AH in TS.

Genotoxic effect of albendazole in pediatric patients with hepatic hydatid disease.

OBJECTIVE: Hydatid disease occurs throughout the world and is treated with both surgery and medical administration of albendazole. Some adverse effects of albendazole are known. However, its genotoxic effect on humans has not been reported yet. In this study, we aimed to investigate the genotoxic effect of albendazole on human lymphocytes in vivo. METHODS: The study involved 14 children (eight males and six females) who had undergone operations for hepatic hydatid disease. The ages of the patients ranged from 6 to 13 years. Genotoxicity of albendazole was evaluated as the frequency of sister chromatid exchange (SCE) and micronucleated cells in the patient's lymphocytes. Prior to and after albendazole treatment, blood samples were obtained from these patients for SCE and micronucleus (MN) studies. SCE and MN frequencies of the patients were measured separately before and after albendazole treatment. RESULTS: All patient SCE values increased significantly after albendazole administration (p<0.001). Similarly, MN frequencies in all the patients increased significantly following albendazole treatment (p<0.001). CONCLUSION: This study revealed that both SCE and MN frequencies are higher after albendazole treatment. The results suggest that albendazole may be genotoxic to human lymphocytes in vivo.

New evidence of premature oxidative DNA damage: mitochondrial DNA deletion in gingival tissue of patients with periodontitis.

BACKGROUND: Overproduction of reactive oxygen species (ROS) causes increased oxidative stress in gingival tissue. It has been generally accepted that increased oxidative stress might contribute to additional damage of lipids, proteins, and DNA molecules. The mitochondrial DNA (mtDNA) mutation is a superb biomarker of oxidative damage. The aim of the present study was to investigate the mtDNA deletions in the gingival tissue of patients with periodontitis and to explain the correlations between mtDNA deletion in gingival tissue and clinical parameters of periodontitis and age. METHODS: Gingival tissue and blood samples were collected from 30 patients with chronic periodontitis (CP group) and 30 healthy control subjects (H group). To determine the clinical condition of each subject, the plaque index, gingival index, clinical attachment level, and probing depth were measured. Using the polymerase chain reaction (PCR) method, we examined the 7.4- and 5-kbp mtDNA deletions in tissue and blood samples. Three different pairs of PCR primers were used in this study. RESULTS: In this study, we did not detect any deletions in blood DNA samples in either the CP or H group. Also, the 7.4-kbp mtDNA deletion was not detected in gingival tissues of subjects. However, the 5-kbp mtDNA deletion was detected in 24 of the 30 subjects (80%) in the CP group and was not detected in the H group (0%). Significant correlations were found between the occurrence of the 5-kbp mtDNA deletion and all clinical parameters (P <0.01). A similar correlation was found between the occurrence of the 5-kbp mtDNA deletion and age (P <0.05). CONCLUSIONS: The overproduction of ROS by activated polymorphonuclear leukocytes in chronic inflammation may lead to premature oxidative damage of the mtDNA. In this study, the occurrence of the 5-kbp mtDNA deletion in 24 periodontitis subjects may be evidence of premature oxidative DNA damage.

Chromosome and sister chromatid exchange studies in Behcet's patients.

Behcet's disease is a chronic multisystemic disease of unknown pathogenesis characterized by four major symptoms: oral aphthous ulcers, skin lesions, ocular symptoms and genital ulcerations. The disease is spread throughout the world, but it is most frequent in Turkey, Japan, Korea and China. Although HLA-Bw51 has been found to predominate in Behcet's cases, the genetic etiology has not yet been clarified. In this study, we investigated the chromosomal abnormalities and sister chromatid exchange rates in patients with Behcet's diseases. Thirty-eight patients with Behcet's disease (diagnosed for the first time) and 30 healthy subjects (as controls) were included in this study. Although numerical and structural chromosomal abnormalities were not detected in our patients, we found an increased rate of sister chromatid exchange in patients over the control groups (P < 0.01). On the basis of these results, we discuss the genetic etiology of Behcet's disease.

Sister chromatid exchange analysis and chromosoma aberration studies in interventional cardiology laboratory workers: one war follow up study.

Invasive cardiology laboratory workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation has a damaging effect on chromosomes. In present study. we investigated the frequency of sister chromatid exchange (SCE) and chromosomal aberrations in 11 invasive cardiology laboratory workers and 11 healthy controls. After a vacation period, we took blood samples for chromosome analysis in months 0, 4, 8 and 12 (last two month period was the nonradiation time). The SCE frequencies did not change significantly after exposure to ionizing radiation in any worker. Our study has revealed that non-specific structural chromosome aberrations such as gaps, isogaps, acentric chromosomes, chromatids and chromosome breakage could be in the 4th and 8th months after ionizing radiation exposure in the metaphase plaques. All abnormal chromosomal effects had disappeared by the end of the two month non-exposure period in each worker. In conclusion, the results suggest that SCE frequencies are not significantly affected in invasive cardiology laboratory workers who are exposed occupationally to ionizing radiation, although some degree of reversible chromosomal aberrations did appear.