Modification of 10 cGy neutron or gamma-rays induced chromosomal damages by hyperthermia: an in vitro study

Background: To evaluate the effects of hyperthermia (HT) on the frequency of chromosomal aberrations induced by a low dose of neutron or Y-rays in human peripheral blood lymphocytes. Materials and Methods: Blood samples were exposed to HT (41.5 degrees C for 30 and 60min, 43 degrees C for 15 and 30min), 10 cGy neutron or Y-rays, HT + neutron/Y, and neutron/Y + HT. After standard cell culture, harvesting, fixation and staining, the chromosomal damages were scored in metaphase plates. Results: HT alone at 41.5 degrees C did not induce chromatid or chromosome aberrations, however, the frequency of damages was significantly higher at 43 C (P<0.05). Furthermore, the chromosomal damages was significantly different when cells were irradiated with neutron or Y-rays alone (P<0.01). HT 1 hr post neutron/Y irradiation significantly induced higher chromosome damages in comparison to HT 1 hr before irradiation (P<0.05). The chromosomal damages were remarkably higher when cells were irradiated with neutron then heated at 43 C for 30 min. Conclusion: Since increasing frequency of chromosome damages increases probability of cell death, application of HT after neutron irradiation (instead of X- or gamma- rays) might be considered as a procedure for cells killing in radiotherapy. Iran. J. Radiat. Res., 2009; 7 (2): 69-7

Relationship study of the verified human epidermal growth factor receptor 2 amplification with other tumor markers and clinicohistopathological characteristics in patients with invasive breast cancer, using chromogenic in situ hybridization

Objective: Human epidermal growth factor receptor 2 (HER-2), as a crucial factor involved in about 20 of breast cancer cases, is one of the most reliable tumor markers to determine prognosis and therapeutic trend of this disease. This marker is generally assessed by immunohistochemistry (IHC) technique. In the cases that result of IHC test cast doubt (+2), the test should be repeated or validated by applying in situ hybridization techniques, like chromogenic in situ hybridization (CISH). In this regard, the goal of current study was to figure out the link between different clinicopathological characteristics of patients suffering from invasive breast cancer, using tumor markers, hormone receptor (HR) and HER-2. Comparing IHC and CISH techniques for evaluating diagnostic value and usefulness of HER-2 were also the other objective of this study. Materials and Methods: Based on this retrospective study, histological markers of 113 individuals suffering from invasive breast cancer -such as estrogen receptor (ER), progesterone receptor, HER-2 receptor, E-cadherin, CK5/6, vimentin and Ki67 were examined by IHC technique. HER-2 amplification of all patients was also evaluated by CISH. Clinicopathological information of the patients was also extracted from medical documents and their associations with tumor markers were statistically evaluated. Results: There is a significant relationship between tumor size, CK5/6 and tumor grade with HR status. Similar relationship was observed between HER-2 status and HR status, as well as vascular invasion (P<0.05). The comparison of HER-2 amplification showed no complete concordance of the result obtained from these two techniques, with score +3. Conclusion: Since the status of HER-2 is very important in decision making of the treatment process, CISH technique is recommended in the malignant conditions as the primary test, instead of IHC. In this study, we also determined that HER-2 expression is greatly correlated with ER- and PR- status. This might propose a better prognosis for HER-2+ patients. © 2019 Royan Institute (ACECR). All rights reserved

Potent radioprotective effect of therapeutic doses of ranitidine and famotidine against gamma-rays induced micronuclei in vivo

ABSTRACT Background: Previous investigations have revealed, cimetidine, a histamine H2-receptor antagonist, show radioprotective effects against gamma-and neutron-induced micronuclei in bone marrow erythrocytes. In this study, the anticlastogenic effects of famotidine and ranitidine, which act similar to cimetidine as histamine H2-receptor antagonists, was investigated. Materials and Methods: Balb/c male mice were injected i.p. with various doses of famotidine and ranitidine two hours before 2 Gy gamma irradiation. Frequency of micronuclei was determined in bone marrow erythrocytes following each treatment. Results: The results indicated that gamma irradiation alone can cause a high frequency of micronuclei formation and decrease cell proliferation ratio. Pre-irradiation injection of famotidine and ranitidine, of various doses, effectively reduced the number of micronucleated polychromatic erythrocytes (MnPCEs), yet has no effect on cell proliferation ratio (PCEs/PCEs+NCEs). In fact, these two drugs reduce the clastogenic effects of gamma rays, while they are ineffective against the cytotoxic properties of gamma rays

Association of elevated frequency of micronuclei in peripheral blood lymphocytes of type 2 diabetes patients with nephropathy complications

The increasing incidence of type 2 diabetes mellitus globally has increased the incidence of diabetes-associated complications such as nephropathy. DNA damage induced by oxidative stress might be one of the important mechanisms in the pathogenesis of diabetic complications. Two hundred Iranian individuals with the conditions of type 2 diabetes, diabetic nephropathy and nephropathy patients with no sign of diabetes and normal unaffected sex- and age-matched controls (50 in each group) were enrolled in the study. The background and the net levels of micronucleus (MN) formation as well as other cellular damages induced after in vitro treatment with 25 μg/ml of bleomycin (BLM) were evaluated using cytokinesis block MNs cytome assay (CBMN cyt) in peripheral blood lymphocytes. The background and net BLM-induced levels of MNs were significantly higher in all patient groups compared with the control (P < 0.01, P < 0.001, respectively). The frequency of MNs was significantly higher in those patients with prior incidence of nephropathy than those without. A positive association was observed between basal and net MN frequency among study groups and also between net genetic damages and serum creatinine value and duration of diabetes. The rate of basal and net apoptosis was significantly higher in patients with hyperglycemia. Our results indicate that increased genomic instability expressed as MNs is associated with nephropathy in all pathological stages. Therefore, implementation of MN assay in clinical level may potentially enhance the quality of management of patients with diabetes and its complications such as nephropathy. © 2016 The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: [email protected]

Cytogenetic sensitivity of G0 lymphocytes of Fanconi anemia patients and obligate carriers to mitomycin C and ionizing radiation

It is well known that Fanconi anemia (FA) patients show a hypersensitivity to the effect of cross-linking agents such as mitomycin C (MMC) and diepoxybutane (DEB), while the sensitivity of these patients to ionizing radiation is still controversial. Fanconi anemia heterozygotes do not show a hypersensitivity to the above mentioned agents compared to normal individuals. To examine the radio-sensitivity of Fanconi anemia patients and heterozygotes, ten patients and 13 heterozygotes were enrolled in this study. Standard metaphase analysis for detection and verification of radio-sensitivity was used to establish the relationship between γ-ray and chromosome breakages in these groups. Statistical analysis was used for the assessment of aberrations including chromatid and chromosome breaks and exchanges. Results of chromosome aberration yield that: (i) differentiation between obligate carriers and the control group after MMC treatment and gamma irradiation was not possible; (ii) homozygotes were clearly distinguishable from heterozygotes and controls after MMC treatment; (iii) FA patients don't show hypersensitivity to gamma irradiation compared to normal controls and heterozygous carriers. Copyright © 2008 S. Karger AG

Chromosomal radiosensitivity in head and neck cancer patients: evidence for genetic predisposition?

The association between chromosomal radiosensitivity and genetic predisposition to head and neck cancer was investigated in this study. In all, 101 head and neck cancer patients and 75 healthy control individuals were included in the study. The G2 assay was used to measure chromosomal radiosensitivity. The results demonstrated that head and neck cancer patients had a statistically higher number of radiation-induced chromatid breaks than controls, with mean values of 1.23 and 1.10 breaks per cell, respectively (P<0.001). Using the 90th percentile of the G2 scores of the healthy individuals as a cutoff value for chromosomal radiosensitivity, 26% of the cancer patients were radiosensitive compared with 9% of the healthy controls (P=0.008). The mean number of radiation-induced chromatid breaks and the proportion of radiosensitive individuals were highest for oral cavity cancer patients (1.26 breaks per cell, 38%) and pharynx cancer patients (1.27 breaks per cell, 35%). The difference between patients and controls was most pronounced in the lower age group (⩽50 years, 1.32 breaks per cell, 38%) and in the non- and light smoking patient group (⩽10 pack-years, 1.28 breaks per cell, 46%). In conclusion, enhanced chromosomal radiosensitivity is a marker of genetic predisposition to head and neck cancer, and the genetic contribution is highest for oral cavity and pharynx cancer patients and for early onset and non- and light smoking patients

Chromosomal radiosensitivity and acute radiation side effects after radiotherapy in tumour patients - a follow-up study

Radiotherapists are highly interested in optimizing doses especially for patients who tend to suffer from side effects of radiotherapy (RT). It seems to be helpful to identify radiosensitive individuals before RT. Thus we examined aberrations in FISH painted chromosomes in in vitro irradiated blood samples of a group of patients suffering from breast cancer. In parallel, a follow-up of side effects in these patients was registered and compared to detected chromosome aberrations. METHODS: Blood samples (taken before radiotherapy) were irradiated in vitro with 3 Gy X-rays and analysed by FISH-painting to obtain aberration frequencies of first cycle metaphases for each patient. Aberration frequencies were analysed statistically to identify individuals with an elevated or reduced radiation response. Clinical data of patients have been recorded in parallel to gain knowledge on acute side effects of radiotherapy. RESULTS: Eight patients with a significantly elevated or reduced aberration yield were identified by use of a t-test criterion. A comparison with clinical side effects revealed that among patients with elevated aberration yields one exhibited a higher degree of acute toxicity and two patients a premature onset of skin reaction already after a cumulative dose of only 10 Gy. A significant relationship existed between translocations in vitro and the time dependent occurrence of side effects of the skin during the therapy period. CONCLUSIONS: The results suggest that translocations can be used as a test to identify individuals with a potentially elevated radiosensitivity

Study of the effect of MMC on the sister chromatid exchange in the human lymphocytes

Some environmental mutagenic agents cause genomic instability and increase susceptibility of DNA damage. One of them is mitomycin C which is connected to DNA as an alkylating factor and affects susceptible cells to reduction reactions. This drug is used in chemotherapy and treatment of tumors. Study of genomic instability in the presence of different concentrations of MMC can show susceptibility of DNA damage in the patients who are under chemotherapy with this drug. For this purpose, SCE is a qualified method that shows the number of sister chromatid exchanges in the metaphasic chromosomes. The number of 10^5 lymphocytic cells which were separated with ficol, were cultured in media (5ml, F12 15%-20% FCS) that contains mitogen of PHA (Phytohemagglutinin) and MMC in the concentrations of 3 ng/ml, 6 ng/ml and 9 ng/ml and a control sample without MMC. The specific concentration of BrdU was added after 24 hours to cell cultures. Then metaphasic cells were halted in the metaphasic stage with colchicine after 48 hours and were stained with SCE method and were studied for the number of sister chromatid exchanges in each metaphasic plaques. Evaluation of 100 metaphasic plates showed that SCE was 3.35% in the control cells while it was 5.43%, 7.1% and 8.13% in the treated cells with MMC in the concentrations of 3 ng/ml, 6 ng/ml and 9 ng/ml. In view of the results, it is clear than MMC can causes genomic instability even in the low concentrations and it can increase SCE so that the level of SCE is become the most with the concentration of 9 ng/ml and the least with the concentration of 3 ng/ml. In view of relation between SCE and DNA damage, we can conclude that the genome of normal cells will be damaged in the presence of MMC and in the patients who are under chemotherapy with this drug. It means that the genome of cells will become sensitive to mutation in the presence of low concentrations of MMC. Therefore we can postulate that we should use the concentrations of less than 3 ng/ml in order to decrease mutagenic effects of MMC in normal cells. Keywords: MMC, SCE, Cancer, Sister chromatid exchang