DBD-FISH Using Specific Chromosomal Region Probes for the Study of Cervical Carcinoma Progression.

Genomic instability is an important biomarker in the progression of cervical carcinoma. DBD-FISH (DNA breakage detection-fluorescence in situ hybridization) is a sensitive method that detects strand breaks, alkali-labile sites, and incomplete DNA excision repair in cells of the cervical epithelium. This technique integrates the microgel immersion of cells from a vaginal lesion scraping and the DNA unwinding treatment with the capacity of FISH integrated into digital image analysis. Cells captured within an agarose matrix are lysed and submerged in an alkaline unwinding solution that generates single-stranded DNA motifs at the ends of internal DNA strand breaks. After neutralization, the microgel is dehydrated and the cells are incubated with DNA-labeled probes. The quantity of a hybridized probe at a target sequence corresponds to the measure of the single-stranded DNA produced during the unwinding step, which is equivalent to the degree of local DNA breakage. DNA damage does not show uniformly throughout the entire DNA of a cell; rather, it is confined to specific chromosomal sites. In this chapter, an overview of the technique is supplied, focusing on its ability for assessing the association between DNA damage in specific sequences and in the progressive stages of cervical carcinoma.

Metal Contents in Feathers from Birds (Rhynchopsitta terrisi, and Columba livia) with Different Ecological Niches.

The metal contaminants can be utilized as an ecological tool to analyze niche partition in birds. As environmental contamination biological indicators, essential (Zn, Cu, and Cr) and non-essential (Pb and Cd) metals in the flight feathers of the Maroon-fronted Parrot and Pigeon with different ecological niches were assessed. The feathers of the parrot were gathered at a national park (Parque Nacional Cumbres de Monterrey) and the feathers of pigeons were collected at an urban site, that is, the city of Monterrey, Mexico. An atomic absorption spectrophotometer was used to establish the concentration of metals in the feathers. Zn, Cu, Cr, Pb, and Cd were detected in the two studied samples. The results obtained in this study exhibited an increase in metal concentrations in pigeon feathers with respect to parrot feathers. In conclusion, employing parrot and pigeon feathers comprises an important tool to track trace-metal occurrence in the environment and metal accumulation in birds. This information is crucial to possess in order to minimize exposure to essential metals in species of wild birds with different ecological niches.

Evaluation of DNA damage in obese children using the chromatin dispersion test.

Childhood obesity predicts adult obesity and may increase the lifetime risk of adverse health outcomes. Obesity is characterized by oxidative stress that can induce DNA damage; however, studies of childhood and adolescent obesity are scarce. We investigated DNA damage due to obesity in Mexican children using the chromatin dispersion test (CDT). We evaluated DNA damage to peripheral lymphocytes of 32 children grouped according to body mass index as normal weight (controls), overweight and obese groups using guidelines from the Centers for Disease Control (CDC). We found that the greatest DNA damage occurred in cells of obese children compared to normal weight and overweight children. Our findings support preventive action to obviate adverse health outcomes due to obesity.

Chromatin Dispersion Test to Asses DNA Damage in Cervical Epithelial Cells.

The chromatin dispersion test (CDT) is based on the removal of nuclear proteins under the assumption that cells with fragmented DNA produce a typical halo of circular DNA loops, which is absent in cells with non-fragmented DNA. This method represents a simple, rapid, accurate, highly reproducible, and inexpensive technique to assess nuclear DNA damage in somatic cells. The visualization of DNA damage and the capacity of the test to provide a threshold value to discriminate between high and low levels of cervical lesions would aid in determining the malignant transformation. All of these advantages associated with the CDT protocol could promote this technique as a tool for the quick and reliable diagnosis of cervical epithelial disorders, even at primary-care centers.

Thermal stress induces pyknosis in pigeon erythrocytes: digital image analysis.

Pyknosis or hypercondensation of chromatin is informative in the understanding of nucleosomal packing in translationally inactive chromatin and in the compression of cell death. However, mechanisms that result in the formation of avian erythrocytes with variant nuclear morphology are poorly understood.Purpose: In this work, we evaluated pyknosis in pigeon erythrocytes treated with thermal stress using Digital Image Analysis (DIA).Materials and methods: Pigeon erythrocytes were treated at thermal stress (33 °C, 43 °C, and 53 °C), and nuclear modifications were analyzed by DIA.Results: Our results showed that thermal stress induced DNA condensation. Based on DNA fluorescent staining and compaction, four subclasses with progressively more pyknotic nuclei each could be distinguished. Alkaline comet assay showed that the presence of pyknotic nuclei was associated with the DNA fragmentation typical of apoptosis. DIA analysis showed a decrease of nuclear area and a significant increase of fluorescence intensity with respect to non-pyknotic nucleus. Additionally we observed nuclear dissolution events associated with swell and loose membrane integrity.Conclusion: These findings can contribute to the evaluation of health and metabolic status in diagnostic cytology, especially in neoplastic conditions and infection by microorganisms.

Quick assessment of DNA damage in cervical epithelial cells using a chromatin dispersion test.

PURPOSE: This study was aimed to quantify genomic DNA breakages in the cervical epithelium cells of patients diagnosed with different grades of cervical lesions using a quick test based on chromatin dispersion after controlled protein depletion. The association between the progressive stages of cervical dysplasia and the levels of DNA damage, taking into account the presence of papillomavirus human (HPV) infection, was investigated. METHODS: A hospital-based unmatched case-control study was conducted during 2018 with a sample of 78 women grouped according to histological diagnosis as follows: 23 women with low grade-squamous intraepithelial lesion (LG-SIL), 34 women with high grade- squamous intraepithelial lesion (HG-SIL), and three women with cervical carcinoma (CC). In parallel, 15 women without cervical lesions were included as a Control cohort. DNA damage levels in cervical epithelial cells were assessed using the chromatin dispersion test (CDT) and controlled in parallel with DNA breakage detection coupled with florescent in situ hybridization (DBD‒FISH) using whole genomic DNA probes. RESULTS: CDT produces different morphotypes in the cervical epithelium that can be associated with the level of DNA breakage revealed with DBD‒FISH. A significant increase of DNA damage was correlated with the histological progression of the patients and human papillomavirus (HPV) infection. CONCLUSION: The CDT is a simple, accurate and inexpensive morphological bioassay to identify different levels DNA damage that can be associated with the level of abnormal cells present in the cervical epithelium in patients who commonly present HPV infection.

DBD-FISH, an effective marker for detecting genotoxicity in buccal mucosa exfoliated cells of patients with oral cancer.

Oral squamous cell carcinoma (OSCC) is characterized by increased genetic instability as an essential variable of event of neoplastic transformation. The aim of this study was to evaluate genomic instability in exfoliated cells from the buccal mucosa of patients with OSCC vs. the control group, using DNA Breakage Detection/Fluorescence In Situ hybridization (DBD-FISH). Exfoliated cells from the buccal mucosa were obtained from 38 patients with oral cancer (case group) and from 10 individuals without oral lesions (control group). DNA damage was evaluated by DBD-FISH using the whole-genome DNA probe and digital imaging analysis. Collaterally, HPV infection was determined utilizing the INNO-LiPA HPV kit. Patients with OSCC showed an increase in the hybridization signal five times more intense than that of the baseline level of DNA damage detected in control individuals. The best cutoff value for predicting oral squamous cell carcinoma was 67.46, and an Odds Ratio (OR) value of 87. HPV detection analysis revealed than one patient with OSCC (2.6%) was positive for HPV. All controls were negative HPV. In conclusion, DBD-FISH permitted the clear visualization of level high of DNA damage in the buccal epithelial cells of patients with OSSC respect to control group. Chromosome instability in oral mucosa may be an individual marker of malignant transformation in OSCC.

Evaluation of the genotoxic effect of heavy metals in pigeons from urban and rural habitat in Monterrey, Mexico, using the chromatin dispersion assay.

PURPOSE: Evaluate genotoxic effect of heavy metals on Pigeon Erythrocytes (PE) from urban and rural habitat (outside of the city) in Monterrey, Mexico, using the chromatin dispersion assay. MATERIALS AND METHODS: We quantified metals concentrations (Cd, Hg, Cu and Pb) in tail feathers of 22 pigeons from an urban and a rural site in northeastern Mexico. DNA damage in peripheral blood erythrocytes was measured by chromatin dispersion assay in 13 pigeon living in urban habitat and in nine living in rural habitat as the control. MicroNucleus (MN) test was used to confirm levels of DNA damage. RESULTS: Birds in urban habitat had highest concentrations in feathers for all the metallic elements analysed with respect to birds in rural habitat. Concentrations of Cu and Hg showed a significant increase (p < 0.05). Our results showed a significant increase of DNA damage in urban-habitat pigeons compared with that of pigeons in rural area. These results were confirmed by a MN test. CONCLUSIONS: Our preliminary findings demonstrate that PE examination via chromatin dispersion assay is a reliable, precise and inexpensive morphological bioassay for evaluating environmental genotoxicity associated with heavy metals. Further studies for evaluating the individual participation of contaminants in DNA damage are needed.

Detection of DNA damage in pigeon erythrocytes using a chromatin dispersion assay.

The monitoring of environmental genotoxicity requires the selection of model organisms as 'sentinels' as well as the development of sensitive and reliable tests for the assessment of DNA damage. The aims of this study were to quantify genomic DNA strand breakage in the erythrocytes of Columba livia induced by thermal stress using the modified chromatin dispersion test and to validate the results by alkaline comet assay and DNA breakage detection-fluorescence in situ hybridization (DBD-FISH). The chromatin dispersion test allowed for clear visualization of erythrocyte cells with DNA damage and of cells with no DNA damage. DNA damage increased significantly with increase in temperature. Additionally, we observed nuclear abnormalities associated with apoptosis, such as karyorrhexis (nuclear disintegration) and karyolysis (nuclear dissolution). These results were validated by alkaline comet assay and DBD-FISH. In conclusion, this procedure is a reliable, precise, and inexpensive morphological bioassay for routine quantitative analysis of DNA breakage in pigeon erythrocytes induced by thermal stress. This method could also be useful as a practical screening tool for genotoxicity testing in environmental care.

Leptin receptor expression during the progression of endometrial carcinoma is correlated with estrogen and progesterone receptors.

INTRODUCTION: The hormone leptin, which is produced in the adipose tissue, may influence tumorigenesis directly via its receptor (Ob-R). Thus, a role for Ob-R in endometrial carcinogenesis has been proposed. However, most studies neither included samples of the entire histological progression of endometrial carcinoma nor examined Ob-R jointly with the estrogen and progesterone receptors (ER and PR, respectively). MATERIAL AND METHODS: To determine the fluctuations of Ob-R, ER, and PR during the histological progression of endometrial carcinoma, we assessed their expression via immunohistochemistry (IHC) in six histological types of endometrium (proliferative, secretory, nonatypical and atypical hyperplasia, and endometrioid and nonendometrioid endometrial carcinoma), in which we performed histopathological and digital scoring for the quantification of receptors. RESULTS: We found that Ob-R expression was positively correlated with that of ER and PR (r = 1, p < 0.001; r = 0.943, p < 0.005, respectively), and there was a significant difference in Ob-R expression among proliferative normal endometrium, hyperplasias, and carcinomas, according to their relative digitally scored Ob-R expression (p < 0.001). In addition, we observed that Ob-R expression in the secretory endometrium was more similar to that of carcinomas than to its proliferative counterpart. CONCLUSIONS: These results indicate that Ob-R expression fluctuates during endometrial carcinogenesis in correlation with ER and PR, suggesting that Ob-R expression in vivo is highly dependent on estrogen and progesterone activities in the endometrium and on its ER and PR status, as suggested previously by in vitro studies.

Two-Tailed Comet Assay (2T-Comet): Simultaneous Detection of DNA Single and Double Strand Breaks.

A modification of the original comet assay was developed for the simultaneous evaluation of DNA single strand breaks (SSBs) and double strand breaks (DSBs) in human spermatozoa. The two-dimensional perpendicular tail comet assay (2T-comet) combines non-denaturing and denaturant conditions to the same sperm nucleoid. In this case, the species-specific deproteinized sperm is first subjected to an electrophoretic field under non-denaturing conditions to mobilize isolated free discrete DNA fragments produced from DSBs; this is then followed by a second electrophoresis running perpendicular to the first one but under alkaline conditions to produce DNA denaturation, exposing SSBs on the same linear DNA chain or DNA fragments flanked by DSBs. This procedure results in a two dimensional comet tail emerging from the core where two types of original DNA affected molecule can be simultaneously discriminated. The 2T-comet is a fast, sensitive, and reliable procedure to distinguish between single and double strand DNA damage within the same cell. It is an innovative method for assessing sperm DNA integrity, which has important implications for human fertility and andrological pathology. This technique may be adapted to assess different DNA break types in other species and other cell types.

DNA damage in acute myeloid leukemia patients of Northern Mexico.

The purpose of this study was to evaluate DNA damage in the whole genome of peripheral blood leukocytes from patients with acute myeloid leukemia (AML) compared with a control group using DNA breakage detection-fluorescent in situ hybridization (DBD-FISH). Our results suggest that the DNA damage detected in patients with newly diagnosed AML was similar to that observed for the controls; this might be explained by the stimulation of a repair pathway by the pathogenesis itself. These findings indicate that inhibiting the repair pathway could be proposed to enhance the efficacy of chemotherapy.

Human Papilloma Virus Detection by INNOLiPA HPV in Prostate Tissue from Men of Northeast Mexico

Background: Prostatic adenocarcinoma by Prosate cancer (PCa) is the most prevalent cancer and the second cause of cancer-related death among men in the Western world. Human papilloma virus (HPV) may be considered as a preventable risk factor. In this study, we assessed the frequencies of HPV infection in prostatic adenocarcinoma and benign prostatic hyperplasia (BPH) cases in Northeast Mexico. Materials and Methods: A total of 87 paraffin-embedded blocks (from 25 and 62 patients with definite diagnoses of BPH and adenocarcinoma, respectively) were selected and subjected to INNOLiPA HPV Genotyping to detect 28 high- and low-risk HPV types. The rates of infection were compared in the two studied groups. Results: INNOLiPA HPV demonstrated great sensitivity for HPV detection on paraffin-embedded tissue. Global prevalence was 14.9% (13/87). HPV infection was positive in 19.4% (12/62) of patients with adenocarcinoma and 4.0% (1/25) of patients with BPH. HPV-11, which is considered to be low risk, was more prevalent. Interestingly, one patient with BPH and six with prostate cancer showed examples considered to be high risk (HPV-18, -51, -52, and -66). Conclusion: A higher rate of HPV infection among Mexican patients with prostatic carcinoma than among those with BPH was observed. HPV infections may thus contribute to the risk of prostate cancer. Further studies are required to elucidate any roles of HPV infection in prostate disease in Mexico and the effect of prevention and treatment of HPV infection on prostatic adenocarcinoma.

Percepción materna del peso del hijo y de niños no emparentados menores de un año / Maternal perception of her child's weight and unrelated children less than 1 year old

OBJETIVOS: Evaluar la percepción materna del peso del hijo (PMPH) y la percepción del peso de niños no emparentados. DISEÑO: Transversal. Emplazamiento. Departamento de Enfermería Materno Infantil en 6 Unidades de Medicina Familiar. PARTICIPANTES: 486 diadas (madre e hijo menor de un año). MEDICIONES PRINCIPALES: Se aplicó la pregunta: "Creo que mi niño/a está", e imágenes de acuerdo al sexo del hijo. Se midieron peso y talla a los lactantes. RESULTADOS: El 20,5% de madres de hijos con sobrepeso (SP) percibieron de forma adecuada esta situación y ninguna de las madres de hijos con obesidad (OB) (κ = 0,14± 0,03, Z = 5,36, p = 0,001). Por imágenes, el 63,3% de las madres de hijos con SP y el 33,3% de madres de hijos con OB percibieron está situación (κ = 0,01± 0,02, Z = 0,73, p = 0,46). La mayoría de las madres seleccionaron la imagen de un niño con SP como la imagen de un niño sano (κ=-0,04±0,01, Z=-2,65, p = 0,008), la imagen de un niño menor de un año (κ=-0,01±0,02, Z=-0,86, p = 0,38) y la imagen que le gustaría para su hijo (κ=0,0004±0,01, Z=0,02, p = 0,98). CONCLUSIÓN: Las madres no perciben el SP-OB de su hijo

AIMS: To evaluate the maternal perception of their child's weight (MPCW) and perception of unrelated children's weight. DESIGN: Cross-sectional. LOCATION: Maternal and Child Nursing Health Department at 6 Units of Family Medicine. PARTICIPANTS: 486 dyads (mother and child under 1 year). Main measurements. The following question was applied: "I think my child is", and images were provided according the child's gender. Children's weight and height were measured. RESULTS: A total of 20.5% of the mothers of overweight (OW) children accurately perceived this situation, while none of the mothers of obese (OB) children did (κ=0.14±0.03, Z=5.36, p=.001). By images, 63.3% of mothers of OW children and 33.3% of mothers of OB children perceived this situation (κ=0.01±0.02, Z=0.73, p=.46). Most mothers selected the image of OW child as the image of a healthy child (κ=-0.04±0.01, Z=-2.65, p=.008), the image of a child under 1 year (κ=-0.01±0.02, Z=-0.86, p=.38) and the image that they would like their child to look like (κ=0.0004±0.01, Z=0.02, p=.98). CONCLUSION: The mothers do not perceive the OW-OB of their children

[Maternal perception of her child's weight and unrelated children less than 1 year old]. / Percepción materna del peso del hijo y de niños no emparentados menores de un año.

AIMS: To evaluate the maternal perception of their child's weight (MPCW) and perception of unrelated children's weight. DESIGN: Cross-sectional. LOCATION: Maternal and Child Nursing Health Department at 6 Units of Family Medicine. PARTICIPANTS: 486 dyads (mother and child under 1 year). MAIN MEASUREMENTS: The following question was applied: "I think my child is", and images were provided according the child's gender. Children's weight and height were measured. RESULTS: A total of 20.5% of the mothers of overweight (OW) children accurately perceived this situation, while none of the mothers of obese (OB) children did (κ=0.14±0.03, Z=5.36, p=.001). By images, 63.3% of mothers of OW children and 33.3% of mothers of OB children perceived this situation (κ=0.01±0.02, Z=0.73, p=.46). Most mothers selected the image of OW child as the image of a healthy child (κ=-0.04±0.01, Z=-2.65, p=.008), the image of a child under 1 year (κ=-0.01±0.02, Z=-0.86, p=.38) and the image that they would like their child to look like (κ=0.0004±0.01, Z=0.02, p=.98). CONCLUSION: The mothers do not perceive the OW-OB of their children.

Evaluation of environmental genotoxicity by comet assay in Columba livia.

The concentrations of recognized or suspected genotoxic and carcinogenic agents found in the air of large cities and, in particular, developing countries, have raised concerns about the potential for chronic health effects in the populations exposed to them. The biomonitoring of environmental genotoxicity requires the selection of representative organisms as "sentinels," as well as the development of suitable and sensitive assays, such as those aimed at assessing DNA damage. The aim of this study was to evaluate DNA damage levels in erythrocytes from Columba livia living in the metropolitan area of Monterrey, Mexico, compared with control animals via comet assay, and to confirm the results via Micronuclei test (MN) and DNA breakage detection-fluorescence in situ hybridization (DBD-FISH). Our results showed a significant increase in DNA migration in animals from the area assayed compared with that observed in control animals sampled in non-contaminated areas. These results were confirmed by MN test and DBD-FISH. In conclusion, these observations confirm that the examination of erythrocytes from Columba livia via alkaline comet assay provides a sensitive and reliable end point for the detection of environmental genotoxicants.

DNA damage in spermatozoa from infertile men with varicocele evaluated by sperm chromatin dispersion and DBD-FISH.

PURPOSE: Evaluation of DNA integrity is an important test, possessing greater diagnostic and prognostic significance for couples requiring assisted reproduction. In this study, we evaluate the levels of DNA damage in infertile patients with varicocele with respect to fertile males by the sperm chromatin dispersion (SCD) test. The presence of DNA breaks in spermatozoa was confirmed by DNA breakage detection-fluorescence in situ hybridization (DBD-FISH). METHODS: In this study, the frequency of sperm cells with fragmented DNA was studied in a group of 20 infertile patients with varicocele and compared with 20 fertile males. The spermatozoa were processed to classify different levels of DNA fragmentation using the Halosperm(®) kit, an improved SCD test, and DBD-FISH. RESULTS: Patients with varicocele showed 25.54 ± 28.17 % of spermatozoa with fragmented DNA, significantly higher than those of the group of fertile subjects (11.54 ± 3.88 %). The proportion of degraded cells in total sperm cells with fragmented DNA was sixfold higher in the case of patients with varicocele. The presence of DNA breaks in spermatozoa was confirmed by DBD-FISH. 5-bp Classical satellite-2 regions showed greater sensitivity to damage or "breakage" than alphoid satellite regions. CONCLUSIONS: Our finding preliminary demonstrated an increase of DNA fragmentation associated to severe sperm damage, in infertile patients with varicocele with respect to fertile males. 5-bp Classical satellite-2 regions showed greater sensitivity to damage or "breakage" than alphoid satellite regions.

Use of DBD-FISH for the study of cervical cancer progression.

DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) is a procedure to detect and quantify DNA breaks in single cells, either in the whole genome or within specific DNA sequences. This methodology combines microgel embedding of cells and DNA unwinding procedures with the power of FISH coupled to digital image analysis. Cells trapped within an agarose matrix are lysed and immersed in an alkaline unwinding solution that produces single-stranded DNA motifs beginning at the ends of internal DNA strand breaks. After neutralization, the microgel is dehydrated and the cells are incubated with fluorescently labeled DNA probes. The amount of hybridized probe at a target sequence correlates with the amount of single-stranded DNA generated during the unwinding step, which is in turn proportional to the degree of local DNA breakage. A general view of the technique is provided, emphasizing its versatility for evaluating the association between DNA damage and progressive stages of cervical neoplasia.

Interpreting sperm DNA damage in a diverse range of mammalian sperm by means of the two-tailed comet assay.

Key ConceptsThe two-dimensional Two-Tailed Comet assay (TT-comet) protocol is a valuable technique to differentiate between single-stranded (SSBs) and double-stranded DNA breaks (DSBs) on the same sperm cell.Protein lysis inherent with the TT-comet protocol accounts for differences in sperm protamine composition at a species-specific level to produce reliable visualization of sperm DNA damage.Alkaline treatment may break the sugar-phosphate backbone in abasic sites or at sites with deoxyribose damage, transforming these lesions into DNA breaks that are also converted into ssDNA. These lesions are known as Alkali Labile Sites "ALSs."DBD-FISH permits the in situ visualization of DNA breaks, abasic sites or alkaline-sensitive DNA regions.The alkaline comet single assay reveals that all mammalian species display constitutive ALS related with the requirement of the sperm to undergo transient changes in DNA structure linked with chromatin packing.Sperm DNA damage is associated with fertilization failure, impaired pre-and post- embryo implantation and poor pregnancy outcome.The TT is a valuable tool for identifying SSBs or DSBs in sperm cells with DNA fragmentation and can be therefore used for the purposes of fertility assessment. Sperm DNA damage is associated with fertilization failure, impaired pre-and post- embryo implantation and poor pregnancy outcome. A series of methodologies to assess DNA damage in spermatozoa have been developed but most are unable to differentiate between single-stranded DNA breaks (SSBs) and double-stranded DNA breaks (DSBs) on the same sperm cell. The two-dimensional Two-Tailed Comet assay (TT-comet) protocol highlighted in this review overcomes this limitation and emphasizes the importance in accounting for the difference in sperm protamine composition at a species-specific level for the appropriate preparation of the assay. The TT-comet is a modification of the original comet assay that uses a two dimensional electrophoresis to allow for the simultaneous evaluation of DSBs and SSBs in mammalian spermatozoa. Here we have compiled a retrospective overview of how the TT-comet assay has been used to investigate the structure and function of sperm DNA across a diverse range of mammalian species (eutheria, metatheria, and prototheria). When conducted as part of the TT-comet assay, we illustrate (a) how the alkaline comet single assay has been used to help understand the constitutive and transient changes in DNA structure associated with chromatin packing, (b) the capacity of the TT-comet to differentiate between the presence of SSBs and DSBs (c) and the possible implications of SSBs or DSBs for the assessment of infertility.

Use of the DBD-FISH technique for detecting DNA breakage in response to high doses of X-rays.

The aim of this study was to generate a dose-response curve using the DNA breakage detection-fluorescent in situ hybridization (DBD-FISH) test as a biomarker of initial genetic effects induced by high doses of X-rays. A dose-response curve was obtained by measuring the ex vivo responses to increasing doses (0-50 Gy) of X-rays in the peripheral blood lymphocytes of ten healthy donors. The overall dose-response curve was constructed using integrated density (ID; area × fluorescence intensity) as a measure of genetic damage induced by irradiation. The correlation coefficient was high (r = 0.934, b(0) = 10.408, and b(1) = 0.094). One-way ANOVA with the Student-Newman-Keuls test for multiple comparisons showed significant differences among the average ln ID values according to dose. Our results suggest the usefulness of the DBD-FISH technique for measuring intrinsic individual cellular radio sensitivity ex vivo.