Anticlastogenic effect of Ginkgo biloba extract in Graves' disease patients receiving radioiodine therapy

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Clinical Applications of Biological Dosimetry in Patients Exposed to Low Dose Radiation Due to Radiological, Imaging or Nuclear Medicine Procedures

Radiation dosimetric biomarkers have found applications beyond radiation protection area and now are actively introduced into clinical practice. Cytogenetic assays appeared to be a valuable tool for individualized quantifying radiation effects in patients, with high capability for assessing genotoxicity of various medical exposure modalities and providing meaningful radiation dose estimates for prognoses of radiation-related cancer risk. This review summarized current data on the use of biological dosimetry methods in patients undergoing various medical irradiations to low doses. The highlighted topics include basic aspects of biological dosimetry and its limitations in the range of low radiation doses, and main patterns of in vivo induction of radiation biomarkers in clinical exposure scenarios, occurring in X-ray diagnostics, computed tomography, interventional radiology, low dose radiotherapy, and nuclear medicine (internally administered ¹³¹I and other radiopharmaceuticals). Additionally, several specific issues, examined by biodosimetry techniques, are analysed, such as contrast media effect, radiation response in pediatric patients, impact of magnetic resonance imaging, evaluation of radioprotectors, detection of patients' abnormal intrinsic radiosensitivity and dose estimation in persons involved in medical radiation incidents. A prognosis of possible directions for further improvements in this area includes the automation of cytogenetic analysis, introduction of molecular biodosimeters and development of multiparametric biodosimetry platforms. A potential approach to the advanced biodosimetry of internal exposure and/or low dose external irradiation is suggested; this can be a multiparametric platform based on the combination of the γ-H2AX foci, dicentric, and translocation assays, each applied in the optimum postexposure time range, with the amalgamation of the dose estimates. The study revealed the necessity of further research, which might clarify medical radiation safety concerns for patients via using stringent biodosimetry methodology.

Therapeutic potential of natural plant products and their metabolites in preventing radiation enteropathy resulting from abdominal or pelvic irradiation

Radiation-induced gastrointestinal injury or radiation enteropathy is an imminent risk during radiation therapy of abdominal or pelvic tumors. Despite remarkable technological advancements in image-guided radiation delivery techniques, the risk of intestinal injury after radiotherapy for abdominal or pelvic cancers has not been completely eliminated. The irradiated intestine undergoes varying degrees of adverse structural and functional changes, which can result in transient or long-term complications. The risk of development of enteropathy depends on dose, fractionation, and quality of radiation. Moreover, the patients' medical condition, age, inter-individual sensitivity to radiation and size of the treatment area are also risk factors of radiation enteropathy. Therefore, strategies are needed to prevent radiotherapy-induced undesirable alteration in the gastrointestinal tract. Many natural plant products, by virtue of their plethora of biological activities, alleviate the adverse effects of radiation-induced injury. The current review discusses potential roles and possible mechanisms of natural plant products in suppressing radiation enteropathy. Natural plant products have the potential to suppress intestinal radiation toxicity.

Evaluation of the physical and biological dosimetry methods in iodine-131-treated patients

The aim of the study was to compare physical and biological dosimetry methods in iodine-131 (I-131)-receiving patients. The present study comprised of 47 patients (mean age: 47.9 ± 15.8 years), treated with I-131. Group I consisted of 17 patients with hyperthyroidism and mean administered activity of this group was 432.9 ± 111 MBq. There were 15 follow-up patients of differentiated thyroid cancer (DTC) in Group II with mean administered activity of 185 ± 22.2 MBq, who were administered scanning dose of I-131. Group III comprised of 15 patients with DTC, ablated with high-dose of I-131, and this group's mean administered activity was 4347.5 ± 695.6 MBq. The whole-body absorbed doses were calculated in all patients both with the Medical Internal Radiation Dosimetry (MIRD) method using MIRDOSE3 software and cytokinesis-block micronucleus (MN) assay-based MN analysis and were compared. The whole-body absorbed dose, calculated by MIRD method, showed very good correlation with the administered I-131 activity (r = 0.89, P < 0.001), but it was moderate in the MN method (r = 0.52, P < 0.01). Absorbed dose estimations with MIRD method were 49.2 ± 20.8 mGy in Group I, 6.5 ± 1.6 mGy in Group II, and 154.3 ± 47.8 mGy in Group III; the differences were statistically significant (P < 0.001), as expected. Pre- and posttreatment MN frequencies differed significantly in all groups (P < 0.05). The whole-body absorbed doses, based on MN method, were 68.2 ± 17.5, 46.0 ± 11.4, and 90.5 ± 26.9 mGy in Groups I–III, respectively. The difference was significant between Group II and Group III (P < 0.01). The mean absorbed dose was 74.6 ± 27.9 mGy with MN versus 68.0 ± 67.1 mGy in MIRD method (P = 0.087) in the entire study population and the correlation was moderate (r = 0.73, P < 0.001). The whole-body absorbed doses, estimated by MN method, showed moderate correlation with administered radioiodine activities in low radioiodine doses and had significantly different and fluctuating values as compared to MIRD method in patients treated with I-131.

Retrospective Biological Dosimetry at Low and High Doses of Radiation and Radioiodine Impact on Individual Susceptibility to Ionizing Radiation

Iodine-131 (I-131) is often used in thyroid diagnostics and therapy. External and internal exposure to radioiodine can lead to molecular and cellular damage in peripheral blood lymphocytes. The aim of this study was to explore the influence of low and high doses of I-131 on susceptibility to ionizing radiation. Study groups consisted of 30 individuals free of thyroid diseases, 41 patients exposed diagnostically to low doses of I-131, and 37 hyperthyroidism patients exposed therapeutically to high doses. The standardized DNA repair competence assay was used to test the efficacy of the fast DNA repair process in G0 cells. Cytogenetic preparations were made in fresh blood samples before and after challenging cells in vitro with X-ray dose. The frequency of sister chromatid exchanges (SCE) and percentage of cells with significantly elevated numbers of SCE were used as cytogenetic biomarkers associated to homologous recombination and compared to reported earlier cytogenetic biomarkers of cancer risk. Strong individual variation in the biomarkers is observed in all investigated groups before and after challenging. Nevertheless, the efficiency of post challenging fast repair is significantly high in the patients exposed to diagnostic I-131 doses than in unexposed control group and linked to decreased cytogenetic damage. However, 5 weeks after administration of therapeutic doses, significant increases of unrepaired post challenging DNA and cytogenetic damages were observed indicating a health risk. Results also suggest that the appearance of cancers in immediate families might influence DNA repair differently in patients exposed to low than to high doses.

Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review

Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies.

Influence of Different Antioxidants on X-Ray Induced DNA Double-Strand Breaks (DSBs) Using γ-H2AX Immunofluorescence Microscopy in a Preliminary Study

Background

Radiation exposure occurs in X-ray guided interventional procedures or computed tomography (CT) and γ-H2AX-foci are recognized to represent DNA double-strand breaks (DSBs) as a biomarker for radiation induced damage. Antioxidants may reduce the induction of γ-H2AX-foci by binding free radicals. The aim of this study was to establish a dose-effect relationship and a time-effect relationship for the individual antioxidants on DSBs in human blood lymphocytes.

Materials and Methods

Blood samples from volunteers were irradiated with 10 mGy before and after pre-incubation with different antioxidants (zinc, trolox, lipoic acid, ß-carotene, selenium, vitamin E, vitamin C, N-acetyl-L-cysteine (NAC) and Q 10). Thereby, different pre-incubation times, concentrations and combinations of drugs were evaluated. For assessment of DSBs, lymphocytes were stained against the phosphorylated histone variant γ-H2AX.

Results

For zinc, trolox and lipoic acid regardless of concentration or pre-incubation time, no significant decrease of γ-H2AX-foci was found. However, ß-carotene (15%), selenium (14%), vitamin E (12%), vitamin C (25%), NAC (43%) and Q 10 (18%) led to a significant reduction of γ-H2AX-foci at a pre-incubation time of 1 hour. The combination of different antioxidants did not have an additive effect.

Conclusion

Antioxidants administered prior to irradiation demonstrated the potential to reduce γ-H2AX-foci in blood lymphocytes.

Systemic oxidative stress to nucleic acids is unaltered following radioiodine therapy of patients with benign nodular goiter

BACKGROUND

Little is known about the whole body oxidative stress burden following radioactive iodine ((131)I) therapy of thyroid diseases.

METHODS

We studied 17 patients with benign nodular goiter treated with (131)I therapy. The targeted thyroid dose was 50 Gy in 11 patients pretreated with 0.1 mg of recombinant human TSH (rhTSH). In 6 patients, the applied thyroid dose was 100 Gy without rhTSH prestimulation. Well-established biomarkers of oxidative stress to RNA (8-oxo-7,8-dihydroguanosine; 8-oxoGuo) and DNA (8-oxo-7,8-dihydro-2'-deoxyguanosine; 8-oxodG) were measured in freshly voided morning urine (normalized against the creatinine concentration) at baseline, and 7 and 21 days after rhTSH (not followed by (131)I), and 7 and 21 days after (131)I therapy, respectively.

RESULTS

The baseline urinary excretions of 8-oxoGuo and 8-oxodG were 2.20 ± 0.84 and 1.63 ± 0.70 nmol/mmol creatinine, respectively. We found no significant changes in the excretion of any of the metabolites, neither after rhTSH stimulation alone nor after (131)I therapy. Also, no significant differences were found between the rhTSH group (low dose, median (131)I: 152 MBq) and the non-rhTSH group (high dose, median (131)I: 419 MBq; 8-oxoGuo: p = 0.66, 8-oxodG: p = 0.71).

CONCLUSION

Systemic oxidative stress, as detected by nucleic acids metabolites in the urine, is not increased after thyroid stimulation with 0.1 mg of rhTSH, or after (131)I therapy. Our method cannot quantify the oxidative stress induced locally in the thyroid gland, but the study supports that (131)I therapy of benign nodular goiter carries no or only a minute risk of developing subsequent malignancies. It remains to be explored whether our findings also apply to hyperthyroid disorders.

Protective and antigenotoxic effect of Ulva rigida C. Agardh in experimental hypothyroid

The presence of chromosomal damage in bone marrow cells affected by several diseases such as thyroid, cancer etc., was detected by the micronucleus (MN) assay. The present study was designed to evaluate: i) volatile components of Ulva rigida, ii) effects of hypothyroidism on bone marrow MN frequency, iii) effects of oral administration of Ulva rigida ethanolic extract (URE) on MN frequency produced by hypothyroidism, and iv) thyroid hormone levels in normal and 6-n-Propylthiouracil (PTU)-induced hypothyroid rats. The volatile components of Ulva rigida was studied using a direct thermal desorption (DTD) technique with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOF/MS). URE administration was of no significant impact on thyroid hormone levels in control group, while PTU administration decreased thyroid hormone levels compared to control group (p < 0.001). Moreover, URE supplementation resulted in a significant decrease in MN frequency in each thyroid group (p < 0.0001). This is the first in vivo study that shows the strong antigenotoxic and protective effect of URE against the genotoxicity produced by hypothyroidism.

Radioprotective agents for the prevention of side effects induced by radioiodine-131 therapy

Radioiodine 131 (131I) has been used worldwide for the ablation of remnant thyroidal tissue after surgery or as the first-line treatment for Graves’ disease. Although the use of 131I is becoming increasingly prevalent, there is evidence suggesting that this treatment is associated with side effects such as salivary gland dysfunction and an increased risk of leukemia. This article aims to review the potential use of radioprotective agents and the side effects induced by 131I therapy. Several synthetic and natural compounds have been investigated in preclinical and clinical studies. The protective agents reduced the toxicity of 131I, mainly in the salivary glands, and mitigated the genetic damage through different mechanisms. There are limited clinical studies evaluating the use of radioprotective agents in patients undergoing radioiodine therapy. However, lemon candies, lemon juice and sugarless chewing gum have been proposed to be beneficial for minimizing the side effects of radioiodine within the salivary glands.

Micronuclei in genotoxicity assessment: from genetics to epigenetics and beyond

Micronuclei (MN) are extra-nuclear bodies that contain damaged chromosome fragments and/or whole chromosomes that were not incorporated into the nucleus after cell division. MN can be induced by defects in the cell repair machinery and accumulation of DNA damages and chromosomal aberrations. A variety of genotoxic agents may induce MN formation leading to cell death, genomic instability, or cancer development. In this review, the genetic and epigenetic mechanisms of MN formation after various clastogenic and aneugenic effects on cell division and cell cycle are described. The knowledge accumulated in literature on cytotoxicity of various genotoxins is precisely reflected and individual sensitivity to MN formation due to single gene polymorphisms is discussed. The importance of rapid MN scoring with respect to the cytokinesis-block micronucleus assay is also evaluated.

Micronucleus frequency among Iraqi thyroid disorder patients

Micronucleus (MN) assay has been extensively used in detection of DNA damage, instability in cancer, and genetic disorders. In the current study, MN, binucleated cells, and nuclear division index (NDI) were investigated in Iraqi patients with thyroid disorders. The results indicated significantly (p < 0.05) increased binucleated cells with micronucleus (BNMN) frequencies in thyroid cancer group (37.58 ± 3.07) versus other thyroid disorder groups (6.60 ± 1.29, 14.90 ± 1.69, 15.56 ± 1.76). On the other hand, the frequency of micronucleus per 1,000 and the NDI were significantly (p < 0.05) decreased in hypothyroidism (MN 1.55 ± 0.36) (NDI 0.009 ± 0.001) versus other thyroid disorder groups (MN: 6.05 ± 0.97, 6.09 ± 0.53, 5.34 ± 0.56) (NDI: 0.049 ± 0.003, 0.032 ± 0.002, 0.025 ± 0.002), with no difference versus healthy group (0.0 ± 0.0). The number of BNMN and MN are parallel to the severity of thyroid disorders which were 6.60 ± 1.29, 14.90 ± 1.69, 15.56 ± 1.76, and 37.58 ± 3.07 for hypothyroidism, thyroid toxic goiter, thyroid nontoxic goiter, and thyroid cancer, respectively. The number of BNMN and MN are parallel to the severity of thyroid disorders which were 6.60 ± 1.29, 14.90 ± 1.69, 15.56 ± 1.76, and 37.58 ± 3.07 for hypothyroidism, thyroid toxic goiter, thyroid nontoxic goiter, and thyroid cancer, respectively. The results also indicate that there were no significant differences among age and sex groups as related with BNMN formation within each thyroid disorder groups and healthy control group.

Radioiodine therapy in benign thyroid diseases: effects, side effects, and factors affecting therapeutic outcome

Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems inevitable in Graves' disease, whereas this risk is much lower when treating toxic nodular goiter. The side effect causing most concern is the potential induction of ophthalmopathy in predisposed individuals. The response to (131)I therapy is to some extent related to the radiation dose. However, calculation of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy, and they may even interact mutually and counteract each other. Numerous studies have evaluated the effect of (131)I therapy, but results have been conflicting due to differences in design, sample size, patient selection, and dose calculation. It seems clear that no single factor reliably predicts the outcome from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or retention) can be stimulated in several ways, including dietary iodine restriction and use of lithium. In particular, recombinant human thyrotropin has gained interest because this compound significantly amplifies the effect of (131)I therapy in patients with nontoxic nodular goiter.

Effect of antioxidants on X-ray-induced γ-H2AX foci in human blood lymphocytes: preliminary observations

PURPOSE

To investigate the effect of a radioprotective oral agent containing a formulation of antioxidants and glutathione-elevating compounds on the extent of x-ray-induced γ-H2AX foci formation.

MATERIALS AND METHODS

The study was approved by local ethics committee and informed consent was obtained from each subject. In vitro experiments with blood lymphocytes of 25 healthy volunteers were performed without antioxidants and with antioxidants added either before or immediately after irradiation (10 mGy). For in vivo/in vitro tests, blood samples were obtained before, 15, 30, and 60 minutes (n=17) after, and 2, 3, and 5 hours (n=11) after oral ingestion of antioxidant pills and were irradiated (10 mGy). DNA double-strand breaks (DSBs) were quantified in isolated lymphocytes 5 minutes (in vitro and in vivo/in vitro) and 15 minutes (in vitro) after irradiation by enumerating γ-H2AX foci. To validate the data, additional in vitro experiments with use of 53BP1 as another independent marker for DSBs were performed. Nonirradiated samples served as controls. Statistical analyses were performed by using Wilcoxon rank-sum tests (in vitro), repeated-measures test, and Dunnett test (in vivo/in vitro).

RESULTS

In the in vitro experiments, 15-minute preincubation with antioxidants significantly reduced mean γ-H2AX foci levels by 23% (P<.0001), whereas addition of antioxidants immediately after irradiation did not lead to a reduction of x-ray-induced foci (P=.6905). Mean 53BP1 foci were also reduced by preincubation with the radioprotectant. In the in vivo/in vitro tests, oral pretreatment with antioxidants also led to a significant reduction of γ-H2AX foci formation; administration 60 minutes before irradiation resulted in a mean foci reduction of 58% (P<.0001).

CONCLUSION

The tested formulation of antioxidants significantly reduced formation of γ-H2AX and 53BP1 foci after irradiation at a radiologic radiation dose typical for computed tomographic imaging; administration 60 minutes prior to irradiation seems to be appropriate and leads to a significant reduction in foci.

The effect of Ginkgo biloba extract on genotoxic damage in patients with differentiated thyroid carcinoma receiving thyroid remnant ablation with iodine-131

BACKGROUND

Radioiodine ((131)I) therapy is usually performed in patients with differentiated thyroid cancer (DTC). Although (131)I is generally considered safe, genotoxic damage has been demonstrated both in vivo and in vitro. The aim of the current study was to evaluate the effect of Ginkgo biloba extract (GBE) on the time-course of appearance, after (131)I therapy for DTC, of plasma factors with chromosome-damaging properties (so-called "clastogenic" factors [CFs]) and of micronuclei (MN) in lymphocytes.

METHODS

Twenty-three patients (median age 42 years, range 18-73) with DTC receiving (131)I activity (3.7 GBq) for thyroid remnant ablation were randomly assigned to receive GBE (120 mg/day for one month; n=10) or placebo (n=13) in a double-blind manner. Blood samples were taken at various intervals (from baseline to 90 days) after (131)I therapy. The frequency of MN in blood lymphocytes was determined, and CFs were assayed in plasma by a method that used MN increase in lymphocytes from an healthy donor as the endpoint of the assay.

RESULTS

MN in blood lymphocytes increased significantly after (131)I treatment in the placebo group, peaking at the 7th day (p=0.002) and slowly declining thereafter. In contrast, in similarly treated patients who were also treated with GBE both before and after (131)I treatment, a significant increase of blood lymphocyte MN level was not observed. In addition, only the placebo group showed a significant, progressive increase in CFs activity. This peaked at the 14th day (p=0.003 vs. baseline) and was still noted for the last plasma sample. The differences in the change in lymphocyte MN and CFs activity between the placebo and GBE-treated groups were significant (p<0.01 and p<0.05, respectively). Thyroid function tests, including serum thyroglobulin (Tg) and anti-Tg antibody levels, were never significantly different.

CONCLUSIONS

GBE may protect from possible oxidative and genotoxic damage associated with (131)I treatment in patients requiring (131)I therapy for thyroid cancer, without affecting the clinical outcome. Further studies with larger cohorts of patients are needed to confirm this report and verify the beneficial effect of GBE in patients requiring (131)I therapy, particularly for those in whom repeated treatments and high activities of (131)I are required.

Non-thermal effects of 2.45 GHz microwaves on spindle assembly, mitotic cells and viability of Chinese hamster V-79 cells

The production of mitotic spindle disturbances and activation of the apoptosis pathway in V79 Chinese hamster cells by continuous 2.45 GHz microwaves exposure were studied, in order to investigate possible non-thermal cell damage. We demonstrated that microwave (MW) exposure at the water resonance frequency was able to induce alteration of the mitotic apparatus and apoptosis as a function of the applied power densities (5 and 10mW/cm(2)), together with a moderate reduction in the rate of cell division. After an exposure time of 15 min the proportion of aberrant spindles and of apoptotic cells was significantly increased, while the mitotic index decreased as well, as compared to the untreated V79 cells. Additionally, in order to understand if the observed effects were due to RF exposure per se or to a thermal effect, V79 cells were also treated in thermostatic bath mimicking the same temperature increase recorded during microwave emission. The effect of temperature on the correct assembly of mitotic spindles was negligible up to 41°C, while apoptosis was induced only when the medium temperature achieved 40°C, thus exceeding the maximum value registered during MW exposure. We hypothesise that short-time MW exposures at the water resonance frequency cause, in V79 cells, reversible alterations of the mitotic spindle, this representing, in turn, a pro-apoptotic signal for the cell line.

Ginkgo biloba extract alters the binding of the sodium [123I] iodide (Na123I) on blood constituents

We evaluated the in vitro effect of an aqueous extract of Ginkgo biloba (EGb) on the distribution in blood cells (BC) and plasma (P) and on the binding of Na(123)I to the blood constituents using precipitation with trichloroacetic acid. The radioactivity percentages insoluble (SF) and insoluble fraction (IF) of blood constituents were determined. The EGb interfered (p<0.05) on the distribution of Na(123)I in the P (from 69.64 to 86.13) and BC (from 30.36 to 13.87) and altered the fixation of the Na(123)I in IF-P and in IF-BC.

Nuclear damage in peripheral lymphocytes of obese and overweight Italian children as evaluated by the gamma-H2AX focus assay and micronucleus test

Childhood obesity, often characterized by a chronic low-grade inflammation, has been associated with an increased risk of developing some types of cancer later in life. Nuclear γ-H2AX foci represent the first detectable response of cells to DNA tumorigenesis lesions, such as the double-strand breaks (DSBs). An excess of micronucleated peripheral lymphocytes was found in subjects with cancer or inflammation-based diseases. We set out to investigate the expression of genome damage, from DNA lesions to chromosome mutations (micronuclei), in overweight and obese children. Using the γ-H2AX focus assay and micronucleus (MN) test, we analyzed peripheral lymphocytes from 119 Italian children classified as normal weight (n=38), overweight (n=20), or obese (n=61). Cultures treated with bleomycin (BLM) were also set up for each child in both assays to check functioning of the apparatus that ensures DNA integrity. We measured serum TNF-α, IL-6, and C-reactive protein (CRP) as markers of inflammation. Overweight and obese children had significantly higher levels of H2AX phosphorylation (0.0191±0.0039 and 0.0274±0.0029 γ-H2AXF/n) and increased MN frequencies (2.30±0.25 and 2.45±0.22‰) than normal-weight children (0.0034±0.0006 γ-H2AXF/n, and 0.92±0.12‰ MN), while all subjects responded to BLM induction, irrespective of their weight status. The fold increase of spontaneous MN frequencies in overweight and obese subjects was 2.5 and 2.7, respectively, well below the corresponding increase in the γ-H2AX foci (5.6- and 8.0-fold, respectively). IL-6 and CRP mean values were significantly higher in obese and overweight children than in controls. Here, we demonstrated that peripheral cells of overweight and obese children showed increased levels of DSBs, which were not completely repaired as part of them has been converted into micronuclei. Characterization of childhood obesity inflammation could be implemented using molecular markers of genome damage.

The lymphocyte cytokinesis-block micronucleus cytome assay and its application in radiation biodosimetry

The cytokinesis-block micronucleus cytome (CBMN Cyt) assay is one of the best-validated methods for measuring chromosome damage in human lymphocytes. This paper describes the methodology, biology, and mechanisms underlying the application of this technique for biodosimetry following exposure to ionizing radiation. Apart from the measurement of micronuclei, it is also possible to measure other important biomarkers within the CBMN Cyt assay that are relevant to radiation biodosimetry. These include nucleoplasmic bridges, which are an important additional measure of radiation-induced damage that originate from dicentric chromosomes as well as the proportion of dividing cells and cells undergoing cell death. A brief account is also given of current developments in the automation of this technique and important knowledge gaps that need attention to further enhance the applicability of this important method for radiation biodosimetry.

Spontaneous and bleomycin-induced chromosome damage in non cancer thyroid patients

BACKGROUND

Presence of chromosome damage in lymphocytes of patients affected by several diseases, including cancer, was detected by the micronucleus (MN) assay. Individual susceptibility to DNA damage, considered as a risk factor for cancer, can be also evaluated using the bleomycin (BLM) sensitivity test.

MATERIALS AND METHODS

We aimed to evaluate spontaneous or BLM-induced MN frequencies in autoimmune (AI, n = 19) and non autoimmune (NAI, n = 11) thyroid patients, not receiving (131)I radiometabolic therapy with respect to a control group of 18 healthy subjects. According to thyroid function, patients were also divided into hypothyroid (n = 10), euthyroid (n = 13) or hyperthyroid (n = 7) subjects.

RESULTS

Spontaneous MN frequencies of AI and NAI patients did not differ from those of controls. Hypothyroid patients had more elevated MN basal levels (9.00 + or - 1.71 per thousand) than hyperthyroid (3.75 + or - 1.17 per thousand, P < 0.05) and euthyroid (5.38 + or - 0.97 per thousand, P < 0.01) patients or healthy subjects (4.17 + or - 0.63 per thousand, P < 0.01). In particular, the hypothyroid AI group showed the highest value (9.79 + or - 2.26 per thousand, P < 0.01). All thyroid patients responded differently to BLM than controls (39.90 + or - 2.48 per thousand vs. 31.08 + or - 2.51 per thousand, P = 0.0377). The NAI group had BLM-induced MN levels (45.00 + or - 2.56 per thousand) significantly higher (P = 0.0215) than AI patients (36.95 + or - 3.49 per thousand) or healthy subjects (31.08 + or - 2.51 per thousand). No significant difference was seen when patients were stratified according to autoimmunity.

CONCLUSIONS

We report that hypothyroid patients exhibit a moderate increase in the level of spontaneous genome damage, and that AI thyroid patients resulted to be less sensitive than NAI patients to the mutagen sensitivity test. In prospective, it may be of interest to reinvestigate hypothyroid patients when correction of their dysfunction is achieved.

Chromosome translocation frequency after radioiodine thyroid remnant ablation: a comparison between recombinant human thyrotropin stimulation and prolonged levothyroxine withdrawal

BACKGROUND

Thyroid remnant ablation of differentiated thyroid carcinoma (DTC) patients is traditionally performed after levothyroxine withdrawal. Recombinant human TSH (rhTSH) administration increases serum TSH levels without inducing hypothyroidism.

AIM

The aim of the study was to investigate the frequency of chromosome translocations in DTC patients after the first (131)I therapeutic dose and compare the frequency of translocations between DTC patients off levothyroxine and those receiving rhTSH.

PATIENTS AND METHODS

A total of 20 DTC patients were randomly assigned to levothyroxine withdrawal [(30 d) group A; n=10, nine women; mean age 48.5+/- 19.2 yr] or rhTSH injections [(0.9 mg im per 2 consecutive days) group B; n=10, eight women; mean age 50.4+/- 18.8 yr] before undergoing (131)I activity (3.7 GBq). The frequency of translocations in peripheral lymphocytes was analyzed by tricolor fluorescence in situ hybridization with whole-chromosome-specific probes for chromosomes 1, 4, and 8. Lymphocytes were stained routinely (about 500 each time).

RESULTS

The two groups showed similar baseline translocation frequency. After (131)I administration, the total chromosomal translocation rate was significantly lower in group B than group A (P = 0.02). The frequency of translocations increased significantly in group A only (P = 0.01 vs. baseline). Rearrangement specifically involved chromosomes 4 and 8 (P = 0.02 vs. baseline).

CONCLUSIONS

Our preliminary data show that in hypothyroid status (131)I ablation therapy induces a higher translocation rate, especially in chromosomes 4 and 8. This finding, in agreement with previous dosimetric reports, suggests that whereas inducing a low extrathyroid exposure, rhTSH reduces the potential risk of chromosomal aberration associated with blood irradiation.

New perspectives for synergy research with the "omic"-technologies

Synergistic effects, understood as true overadditive effects, are often observed in experimental and clinical studies using phytopharmaceuticals. The introduction of the "omic"-technologies is now opening new perspectives in rationalizing these effects and making use of them in the development of a new generation of phytopharmaceuticals. This review describes possible mechanism of synergistic actions of herbal drugs by mono- and multitargeting and by the activation of signal cascades. It examines the possibilities of the standardization of single and multi component plant extracts and the prediction and assessment of the toxicity and safety of plant extracts with the support of the "omic"-technologies. It further discusses the use of phytopharmaceuticals in the context of an "individualized medicine". It makes proposals how to use the "omic"-technologies to rationalize and develop combination therapies of phytopharmaceuticals and synthetic drugs to minimize adverse reactions (ARs) or improve the therapeutic efficacy. Examples of clinical studies are given which explore already the potential of such co-medications. Modern medical therapy has acknowledged for quite some time the usefulness of combination therapies in the treatment of multifactorial diseases like cancer, cardiovascular or rheumatic diseases. The term "synergy" is rarely used in this context, the combinatory mechanisms of actions seldom completely understood and the potentially occurring adverse reactions feared. A systematic exploitation of synergy effects of phytomedical interventions alone or in combination with synthetic drugs should lead in a long term perspective to the discovery and development of more rational evidence-based interventions in the prevention and therapy of multifactorial diseases and should thereby enrich modern pharmacotherapy.

Transcriptomic analysis of EGb 761-regulated neuroactive receptor pathway in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

EGb 761, a well-defined extract from Ginkgo biloba, has been widely used in patients with cerebral disorders.

AIM OF THE STUDY

Although EGb 761 exhibits neuroprotective effects and exerts beneficial effects on many neurological disorders, its mechanism on the neuronal functions is unclear so far.

MATERIALS AND METHODS

In this study, we used oligonucleotide microarray technique to investigate the effect of EGb 761 on the transcriptional profile of mouse genes. RNA samples were obtained from frontal cortex, straitum, and kidneys after the oral administration of EGb 761 for seven consecutive days.

RESULTS

Our data showed that EGb 761 significantly altered the neuroactive ligand-receptor interaction pathway in frontal cortex but not in straitum and kidney. Then we analyzed 26 receptor genes that were significantly altered by EGb 761 in this pathway and found that EGb 761 treatment highly up-regulated the subgroup of dopamine receptors, especially dopamine receptor 1a (Drd1a), in frontal cortex. Quantitative real-time reverse transcription-polymerase chain reaction and immunohistochemical staining confirmed the increased level of Drd1a expression after EGb 761 treatment.

CONCLUSIONS

In summary, we investigated for the first time the overall effects of EGb 761 on the gene expression in brain using a powerful systemic biological technique. Our results suggested that EGb 761 altered unique pathways and regulated the expressions of some specific neuronal receptor genes exclusively in frontal cortex.

Is the genotoxic effect of magnetic resonance negligible? Low persistence of micronucleus frequency in lymphocytes of individuals after cardiac scan

Magnetic resonance imaging is a diagnostic technique widely used in medicine and showing a growing impact in cardiology. Biological effects associated to magnetic resonance electromagnetic fields have received far little attention, but it cannot be ruled out that these fields can alter DNA structure. The present study aimed at to identify possible DNA damage induced by magnetic resonance scan in humans. Lymphocyte cultures from healthy subjects had been exposed into magnetic resonance device for different times and under different variable magnetic exposure in order to build dose-effect curves, using micronuclei induction as biological marker. Replicate cultures were also left for 24h at room temperature before stimulation, to verify possible damage recovery. Furthermore, micronuclei induction and recovery up to 120h have been also evaluated in circulating lymphocytes of individuals after cardiac scan. A dose-dependent increase of micronuclei frequency was observed in vitro. However after 24h, the frequency returns to control value when the exposure is within diagnostic dosage. After in vivo scan, a significant increase in micronuclei is found till 24h, after the frequencies slowly return to control value.