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Barrera LM, Ortiz LD, Grisales HDJ, Camargo M. Survival analysis and associated factors of highgrade glioma patients. BIOMEDICA : REVISTA DEL INSTITUTO NACIONAL DE SALUD 2024; 44:191-206. [PMID: 39088535 PMCID: PMC11374120 DOI: 10.7705/biomedica.6742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/18/2024] [Indexed: 08/03/2024]
Abstract
Introduction High-grade gliomas are the most common primary brain tumors in adults, and they usually have a quick fatal course. Average survival is 18 months, mainly, because of tumor resistance to Stupp protocol. Objective To determine high-grade glioma patient survival and the effect of persuasion variables on survival. Materials and methods We conducted a longitudinal descriptive study in which 80 untreated recently diagnosed high-grade glioma patients participated. A survey was conducted regarding their exposure to some risk factors, degree of genetic instability in peripheral blood using micronucleus quantification on binuclear lymphocytes, micronuclei in reticulocytes and sister-chromatid exchanges in lymphocytes. In the statistical analysis, this study constructed life tables, used the Kaplan-Meier, and the log-rank test, and in the multivariate analysis, a Cox proportional hazards model was constructed. Results Eighty patients' clinical, demographic and lifestyle characteristics were analyzed, as well as their survival rates and the average survival time is 784 days (interquartile range: 928). Factors like age, exposure at work to polycyclic hydrocarbons and the number of sister-chromatid exchanges in lymphocytes in the first sampling was significantly survivalrelated in the multivariate analysis. Conclusion We determined that only three of the analyzed variables have an important effect on survival time when it comes to high-grade glioma patients.
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Affiliation(s)
- Lina Marcela Barrera
- Grupo de Investigación en Ciencias Médicas, Escuela Ciencias de la Vida, Programa de Medicina, Universidad EIA, Medellín, Colombia
| | - Leon Darío Ortiz
- Instituto de Cancerología, Clínica Las Américas, Medellín, Colombia
| | - Hugo de Jesús Grisales
- Grupo de Investigación Demografía y Salud, Facultad Nacional de Salud Pública, Universidad de Antioquia, Medellín, Colombia
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Wilkins RC, Rodrigues M, Beaton-Green LA. The Imaging Flow Cytometry-Based Cytokinesis-Block MicroNucleus (CBMN) Assay. Methods Mol Biol 2023; 2635:103-122. [PMID: 37074659 DOI: 10.1007/978-1-0716-3020-4_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
The dose of ionizing radiation received by an individual can be determined using biodosimetry methods which measure biomarkers of exposure in tissue samples from that individual. These markers can be expressed in many ways, including DNA damage and repair processes. Following a mass casualty event involving radiological or nuclear material, it is important to rapidly provide this information to medical responders to assist in the medical management of potentially exposed casualties. Traditional methods of biodosimetry rely on microscope analysis, making them time-consuming and labor-intensive. To increase sample throughput following a large-scale radiological mass casualty event, several biodosimetry assays have been adapted for analysis by imaging flow cytometry. This chapter briefly reviews these methods with a focus on the most current methodology to identify and quantify micronuclei in binucleated cells within the cytokinesis-block micronucleus assay using an imaging flow cytometer.
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Affiliation(s)
- Ruth C Wilkins
- Consumer and Clinical Radiation Protection Bureau, Health Canada, Ottawa, ON, Canada.
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Kirby C, Baig A, Avlasevich SL, Torous DK, Tian S, Singh P, Bemis JC, Saubermann LJ, Dertinger SD. Dextran sulfate sodium mouse model of inflammatory bowel disease evaluated for systemic genotoxicity via blood micronucleus and Pig-a gene mutation assays. Mutagenesis 2020; 35:161-167. [PMID: 32050029 DOI: 10.1093/mutage/geaa006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/24/2020] [Indexed: 12/31/2022] Open
Abstract
Inflammatory bowel disease (IBD) is an important risk factor for gastrointestinal cancers. Inflammation and other carcinogenesis-related effects at distal, tissue-specific sites require further study. In order to better understand if systemic genotoxicity is associated with IBD, we exposed mice to dextran sulfate sodium salt (DSS) and measured the incidence of micronucleated cells (MN) and Pig-a mutant phenotype cells in blood erythrocyte populations. In one study, 8-week-old male CD-1 mice were exposed to 0, 1, 2, 3 or 4% w/v DSS in drinking water. The 4-week in-life period was divided into four 1-week intervals-alternately on then off DSS treatment. Low volume blood samples were collected for MN analysis at the end of each week, and cardiac blood samples were collected at the end of the 4-week period for Pig-a analyses. The two highest doses of DSS were observed to induce significant increases in reticulocyte frequencies. Even so, no statistically significant treatment-related effects on the genotoxicity biomarkers were evident. While one high-dose mouse showed modestly elevated MN frequencies during the DSS treatment cycles, it also exhibited exceptionally high reticulocyte frequencies (e.g. 18.7% at the end of the second DSS cycle). In a second study, mice were treated with 0 or 4% DSS for 9-18 consecutive days. Exposure was continued until rectal bleeding or morbidity was evident, at which point the treatment was terminated and blood was collected for MN analysis. The Pig-a assay was conducted on samples collected 29 days after the start of treatment. The initial blood specimens showed highly elevated reticulocyte frequencies in DSS-exposed mice (mean ± SEM = 1.75 ± 0.10% vs. 13.04 ± 3.66% for 0 vs. 4% mice, respectively). Statistical analyses showed no treatment-related effect on MN or Pig-a mutant frequencies. Even so, the incidence of MN versus reticulocytes in the DSS-exposed mice were positively correlated (linear fit R2 = 0.657, P = 0.0044). Collectively, these results suggest that in the case of the DSS CD-1 mouse model, systemic effects include stress erythropoiesis but not remarkable genotoxicity. To the extent MN may have been slightly elevated in a minority of individual mice, these effects appear to be secondary, likely attributable to stimulated erythropoiesis.
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Affiliation(s)
| | - Ayesha Baig
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY
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Albertini RJ, Kaden DA. Mutagenicity monitoring in humans: Global versus specific origin of mutations. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 786:108341. [PMID: 33339577 DOI: 10.1016/j.mrrev.2020.108341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/08/2020] [Accepted: 10/14/2020] [Indexed: 01/19/2023]
Abstract
An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only occur in developing bone marrow (BM) cells. Reviewed here are 9 currently-employed human mutagenicity biomonitoring assays. Several assays measure chromosome-level events in circulating T-lymphocytes (T-cells), i.e., traditional analyses of aberrations, translocation studies involving chromosome painting and fluorescence in situ hybridization (FISH) and determinations of micronuclei (MN). Other T-cell assays measure gene mutations. i.e., hypoxanthine-guanine phosphoriboslytransferase (HPRT) and phosphoribosylinositol glycan class A (PIGA). In addition to the T-cell assays, also reviewed are those assays that measure events in peripheral blood cells that necessarily arose in BM cells, i.e., MN in reticulocytes; glycophorin A (GPA) gene mutations in red blood cells (RBCs), and PIGA gene mutations in RBC or granulocytes. This review considers only cell culture- or cytometry-based assays to describe endpoints measured, methods, optimal sampling times, and sample summaries of typical quantitative and qualitative results. However, to achieve its intended focus on the target cells where events occur, kinetics of the cells of peripheral blood that derive at some point from precursor cells are reviewed to identify body sites and tissues where the genotoxic events originate. Kinetics indicate that in normal adults, measured events in T-cells afford global assessments of in vivo mutagenicity but are not specific for BM effects. Therefore, an agent's capacity for inducing mutations in BM cells cannot be reliably inferred from T-cell assays as the magnitude of effect in BM, if any, is unknown. By contrast, chromosome or gene level mutations measured in RBCs/reticulocytes or granulocytes must originate in BM cells, i.e. in RBC or granulocyte precursors, thereby making them specific indicators for effects in BM. Assays of mutations arising directly in BM cells may quantitatively reflect the mutagenicity of potential leukemogenic agents.
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Affiliation(s)
- Richard J Albertini
- University of Vermont, 111 Colchester Avenue, Burlington, VT 05401, United States
| | - Debra A Kaden
- Ramboll US Consulting, Inc., 101 Federal Street, Suite 1900, Boston, MA 02110, United States.
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Torous DK, Avlasevich SL, Khattab MG, Baig A, Saubermann LJ, Chen Y, Bemis JC, Lovell DP, Walker VE, MacGregor JT, Dertinger SD. Human blood PIG-A mutation and micronucleated reticulocyte flow cytometric assays: Method optimization and evaluation of intra- and inter-subject variation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:807-819. [PMID: 32572998 PMCID: PMC8582004 DOI: 10.1002/em.22393] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 05/05/2023]
Abstract
We previously described flow cytometry-based methods for scoring the incidence of micronucleated reticulocytes (MN-RET) and PIG-A mutant phenotype reticulocytes (MUT RET) in rodent and human blood samples. The current report describes important methodological improvements for human blood analyses, including immunomagnetic enrichment of CD71-positive reticulocytes prior to MN-RET scoring, and procedures for storing frozen blood for later PIG-A analysis. Technical replicate variability in MN-RET and MUT RET frequencies based on blood specimens from 14 subjects, intra-subject variability based on serial blood draws from 6 subjects, and inter-subject variation based on up to 344 subjects age 0 to 73 years were quantified. Inter-subject variation explained most of the variability observed for both endpoints (≥77%), with much lower intra-subject and technical replicate variability. The relatively large degree of inter-subject variation is apparent from mean and standard deviation values for MN-RET (0.15 ± 0.10%) and MUT RET (4.7 ± 5.0 per million, after omission of two extreme outliers). The influences of age and sex on inter-subject variation were investigated, and neither factor affected MN-RET whereas both influenced MUT RET frequency. The lowest MUT RET values were observed for subjects <11 years old, and males had moderately higher frequencies than females. These results indicate that MN-RET and MUT RET are automation-compatible biomarkers of genotoxicity that bridge species of toxicological interest to include human populations. These data will be useful for appropriately designing future human studies that include these biomarkers of genotoxicity, and highlight the need for additional work aimed at identifying the sources of inter-individual variability reported herein.
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Affiliation(s)
| | | | - Mona G. Khattab
- Department of Pediatrics, Baylor College of Medicine, Texas Children’s Hospital, Houston, Texas
| | - Ayesha Baig
- Department of Pediatrics, University of Rochester Medical Center, Rochester, New York
| | | | - Yuhchyau Chen
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York
| | | | | | - Vernon E. Walker
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
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Micronucleus Assay: The State of Art, and Future Directions. Int J Mol Sci 2020; 21:ijms21041534. [PMID: 32102335 PMCID: PMC7073234 DOI: 10.3390/ijms21041534] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/16/2022] Open
Abstract
During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among the other genotoxicity tests, its usefulness in different applications and visibility by international organizations, such as International Atomic Energy Agency, Organization for Economic Co-operation and Development and International Organization for Standardization. In addition, the mechanism of micronuclei formation is discussed. Finally, foreseen directions of the MN development are pointed, such as automation, buccal cells MN and chromothripsis phenomenon.
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Flow cytometry in peripheral blood reticulocytes as a marker of chromosome instability in highgrade glioma patients. BIOMEDICA 2018; 38:379-387. [PMID: 30335243 DOI: 10.7705/biomedica.v38i4.3882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 03/01/2018] [Indexed: 11/21/2022]
Abstract
Introduction: The quantification of chromosomal instability is an important parameter to assess genotoxicity and radiosensitivity. Most conventional techniques require cell cultures or laborious microscopic analyses of chromosomes or nuclei. However, a flow cytometry that selects the reticulocytes has been developed as an alternative for in vivo studies, which expedites the analytical procedures and increases up to 20 times the number of target cells to be analyzed.
Objectives: To standardize the flow cytometry parameters for selecting and quantifying the micronucleated reticulocytesCD71+ (MN-RET) from freshly drawn peripheral blood and to quantify the frequency of this abnormal cell subpopulation as a measure of cytogenetic instability in populations of healthy volunteers (n =25), and patients (n=25), recently diagnosed with high-grade gliomas before the onset of treatment.
Materials and methods: Blood cells were methanol-fixed and labeled with anti-CD-71-PE for reticulocytes, antiCD-61-FITC for platelet exclusion, and propidium iodide for DNA detection in reticulocytes. The MN-RETCD71+ cell fraction was selected and quantified with an automatic flow cytometer.
Results: The standardization of cytometry parameters was described in detail, emphasizing the selection and quantification of the MN-RETCD71+ cellular fraction. The micronuclei basal level was established in healthy controls. In patients, a 5.2-fold increase before the onset of treatment was observed (p <0.05).
Conclusion: The data showed the usefulness of flow cytometry coupled with anti-CD-71-PE and anti-CD-61-FITC labeling in circulating reticulocytes as an efficient and high resolution method to quantify chromosome instability in vivo. Finally, possible reasons for the higher average of micronuclei in RETCD71+ cells from untreated high-grade glioma patients were discussed.
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Khattab M, Walker DM, Albertini RJ, Nicklas JA, Lundblad LK, Vacek PM, Walker VE. Frequencies of micronucleated reticulocytes, a dosimeter of DNA double-strand breaks, in infants receiving computed tomography or cardiac catheterization. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2017; 820:8-18. [DOI: 10.1016/j.mrgentox.2017.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/18/2022]
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Inter-laboratory validation of the in-vivo flow cytometric micronucleus analysis method (MicroFlow®) in China. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 772:6-13. [PMID: 25308541 DOI: 10.1016/j.mrgentox.2014.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 03/19/2014] [Accepted: 04/30/2014] [Indexed: 12/23/2022]
Abstract
Although inter-laboratory validation efforts of the in-vivo micronucleus (MN) assay based on flow cytometry (FCM) have taken place in the EU and US, none have been organized in China. Therefore, an inter-laboratory study that included eight laboratories in China and one experienced reference laboratory in the US was coordinated to validate the in-vivo FCM MicroFlow(®) method to determine the frequency of micro-nucleated reticulocytes (MN-RETs) in rat blood. Assay reliability and reproducibility were evaluated with four known genotoxicants, and the results obtained with the FCM method were compared with the outcome of the traditional evaluation of bone-marrow micronuclei by use of microscopy. Each of the four chemicals was tested at three sites (two in China and the one US reference laboratory). After three consecutive daily exposures to a genotoxicant, blood and bone-marrow samples were obtained from rats 24h after the third dose. MN-RET frequencies were measured in 20,000 RET in blood by FCM, and micro-nucleated polychromatic erythrocyte (MN-PCE) frequencies were measured in 2,000 PCEs in bone marrow by microscopy. For both methods, each genotoxicant was shown to induce a statistically significant increase in the frequency of MN after treatment with at least one dose. Where more doses than one caused an increase, responses occurred in a dose-dependent manner. Spearman's correlation coefficient (rs) for FCM-based MN-RET vs microscopy-based MN-PCE measurements (eight experiments, 200 paired measurements) was 0.723, indicating a high degree of correspondence between methods and compartments. The rs value for replicate FCM MN-RET measurements performed at the eight collaborative laboratories was 0.940 (n=200), and between the eight FCM laboratories with the reference laboratory was 0.933 (n=200), suggesting that the automated method is very well transferable between laboratories. The FCM micronucleus analysis method is currently used in many countries worldwide, and these data support its use for evaluating the in-vivo genotoxic potential of test chemicals in China.
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Nottage KA, Ware RE, Winter B, Smeltzer M, Wang WC, Hankins JS, Dertinger SD, Shulkin B, Aygun B. Predictors of splenic function preservation in children with sickle cell anemia treated with hydroxyurea. Eur J Haematol 2014; 93:377-83. [PMID: 24796940 DOI: 10.1111/ejh.12361] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND More than 90% of children with sickle cell anemia (SCA) lose splenic function by the age of 2 yrs. Splenic function may improve with hydroxyurea, but previous studies are conflicting. We prospectively evaluated the effect of hydroxyurea on splenic filtrative function. METHODS Children with SCA enrolled in the Hydroxyurea Study of Long-Term Effects (HUSTLE-NCT00305175) underwent clinical evaluations including Tc(99) m liver-spleen (LS) scans before hydroxyurea initiation and after 3 yrs of treatment to maximum tolerated dose (MTD). LS scans were classified as follows: no uptake, <10% uptake, decreased but ≥10% uptake, and normal. RESULTS Mean age (N = 40) was 9.1 yrs, range 2.3-17.0. After 3 yrs of treatment, 13 (33%) had uptake on LS scan. These 13 children were younger (median age 6.0 vs. 10.6 yrs, P = 0.008), had a higher HbF at baseline (mean 10.2% vs. 5.8%, P = 0.004) and after 3 yrs (22.9% vs. 13.9%, P < 0.001), achieved MTD more rapidly (median 288 vs. 358 d, P = 0.021), and were more likely to have baseline splenic uptake (P < 0.001). CONCLUSIONS Hydroxyurea at MTD is associated with preserved or improved splenic filtrative function, with 33% demonstrating LS scan uptake after 3 yrs. Younger age, higher %HbF, and baseline splenic function are associated with a favorable outcome.
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Affiliation(s)
- Kerri A Nottage
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA
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11
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Comparison of three-colour flow cytometry and slide-based microscopy for the scoring of micronucleated reticulocytes in rat bone-marrow and peripheral blood. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 758:12-7. [DOI: 10.1016/j.mrgentox.2013.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/11/2013] [Accepted: 07/08/2013] [Indexed: 11/18/2022]
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McGann PT, Flanagan JM, Howard TA, Dertinger SD, He J, Kulharya AS, Thompson BW, Ware RE. Genotoxicity associated with hydroxyurea exposure in infants with sickle cell anemia: results from the BABY-HUG Phase III Clinical Trial. Pediatr Blood Cancer 2012; 59:254-7. [PMID: 22012708 PMCID: PMC3277805 DOI: 10.1002/pbc.23365] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/06/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND The laboratory and clinical benefits of hydroxyurea therapy for children with sickle cell anemia (SCA) are well recognized, but treatment in young patients is limited in part by concerns about long-term genotoxicity, and specifically possible carcinogenicity. PROCEDURE The Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG) was a multicenter double-blinded placebo-controlled randomized clinical trial (NCT00006400) testing whether hydroxyurea could prevent chronic organ damage in very young patients with SCA. An important secondary objective was the measurement of acquired genotoxicity using three laboratory assays: chromosomal karyotype, illegitimate VDJ recombination events, and micronucleated reticulocyte formation. RESULTS Our data indicate that hydroxyurea treatment was not associated with any significant increases in genotoxicity compared to placebo treatment. CONCLUSIONS These data provide additional support to the safety profile of hydroxyurea for young patients with SCA, and suggest that genotoxicity in this patient population is low.
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Cervantes-Ríos E, Ortiz-Muñiz R, Martínez-Hernández AL, Cabrera-Rojo L, Graniel-Guerrero J, Rodríguez-Cruz L. Malnutrition and infection influence the peripheral blood reticulocyte micronuclei frequency in children. Mutat Res 2012; 731:68-74. [PMID: 22119781 DOI: 10.1016/j.mrfmmm.2011.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 10/25/2011] [Accepted: 11/10/2011] [Indexed: 05/31/2023]
Abstract
Malnutrition is a serious public health problem that affects approximately one third of all children. Developing countries have the highest incidence of malnourished children, and approximately 60% of deaths that occur in children under five are directly related to malnutrition and associated diseases. The relationship between malnutrition and genetic damage has been widely studied in humans and animal models. The micronucleus (MN) assay is useful in detecting chromosome damage induced by several factors. The aim of this study was to evaluate the effects of infection and malnutrition on the frequency of MN in erythrocytes from the peripheral blood of well-nourished, uninfected (WN) and well-nourished, infected (WNI) children, and moderately malnourished (UNM) and severely malnourished (UNS) children, both with infection, using a flow cytometric analysis technique. The percentage of reticulocytes (RETs) was significantly higher (1.5-fold) in WNI children than well-nourished controls. In addition, the UNS group had a 2.2-fold increase in the percentage of RETs compared to the WNI group. The frequency of micronucleated reticulocytes (MN-RETs) was 2.5 times greater, in WNI group compared to the WN group. These frequencies were significantly higher (1.7- and 2.1-fold) in UNM and UNS, respectively, compared to the WNI group. The results suggest that infection and malnutrition induce DNA damage in children.
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Affiliation(s)
- Elsa Cervantes-Ríos
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, Mexico
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McKeon M, Xu Y, Kirkland D, Schmuck G, Krebsfänger N, Avlasevich SL, Dertinger SD. Cyclophosphamide and etoposide canine studies demonstrate the cross-species potential of the flow cytometric peripheral blood micronucleated reticulocyte endpoint. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 742:79-83. [DOI: 10.1016/j.mrgentox.2011.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 12/12/2011] [Accepted: 12/14/2011] [Indexed: 12/01/2022]
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Strategies in case of positive in vivo results in genotoxicity testing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 723:121-8. [DOI: 10.1016/j.mrgentox.2010.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/08/2010] [Indexed: 01/23/2023]
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Lynch AM, Sasaki JC, Elespuru R, Jacobson-Kram D, Thybaud V, De Boeck M, Aardema MJ, Aubrecht J, Benz RD, Dertinger SD, Douglas GR, White PA, Escobar PA, Fornace A, Honma M, Naven RT, Rusling JF, Schiestl RH, Walmsley RM, Yamamura E, van Benthem J, Kim JH. New and emerging technologies for genetic toxicity testing. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:205-223. [PMID: 20740635 DOI: 10.1002/em.20614] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/02/2010] [Accepted: 06/07/2010] [Indexed: 05/29/2023]
Abstract
The International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing established an Emerging Technologies and New Strategies Workgroup to review the current State of the Art in genetic toxicology testing. The aim of the workgroup was to identify promising technologies that will improve genotoxicity testing and assessment of in vivo hazard and risk, and that have the potential to help meet the objectives of the IVGT. As part of this initiative, HESI convened a workshop in Washington, DC in May 2008 to discuss mature, maturing, and emerging technologies in genetic toxicology. This article collates the abstracts of the New and Emerging Technologies Workshop together with some additional technologies subsequently considered by the workgroup. Each abstract (available in the online version of the article) includes a section addressed specifically to the strengths, weaknesses, opportunities, and threats associated with the respective technology. Importantly, an overview of the technologies and an indication of how their use might be aligned with the objectives of IVGT are presented. In particular, consideration was given with regard to follow-up testing of positive results in the standard IVGT tests (i.e., Salmonella Ames test, chromosome aberration assay, and mouse lymphoma assay) to add weight of evidence and/or provide mechanism of action for improved genetic toxicity risk assessments in humans.
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Rogers ZR, Wang WC, Luo Z, Iyer RV, Shalaby-Rana E, Dertinger SD, Shulkin BL, Miller JH, Files B, Lane PA, Thompson BW, Miller ST, Ware RE. Biomarkers of splenic function in infants with sickle cell anemia: baseline data from the BABY HUG Trial. Blood 2011; 117:2614-7. [PMID: 21217080 PMCID: PMC3062353 DOI: 10.1182/blood-2010-04-278747] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 12/07/2010] [Indexed: 11/20/2022] Open
Abstract
We evaluated spleen function in 193 children with sickle cell anemia 8 to 18 months of age by (99m)Tc sulfur-colloid liver-spleen scan and correlated results with clinical and laboratory parameters, including 2 splenic biomarkers: pitted cell counts (PIT) and quantitative Howell-Jolly bodies (HJB) enumerated by flow cytometry. Loss of splenic function began before 12 months of age in 86% of infants in association with lower total or fetal hemoglobin and higher white blood cell or reticulocyte counts, reinforcing the need for early diagnosis and diligent preventive care. PIT and HJB correlated well with each other and liver-spleen scan results. Previously described biomarker threshold values did define patients with abnormal splenic function, but our data suggest that normal spleen function is better predicted by PIT of ≤1.2% or HJB ≤55/10(6) red blood cells and absent function by PIT ≥4.5% or HJB ≥665/10(6). HJB is methodologically advantageous compared with PIT, but both are valid biomarkers of splenic function. This trial was registered at www.clinicaltrials.gov as #NCT00006400.
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Affiliation(s)
- Zora R Rogers
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9063, USA.
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Costa C, Silva S, Neves J, Coelho P, Costa S, Laffon B, Snawder J, Teixeira JP. Micronucleus frequencies in lymphocytes and reticulocytes in a pesticide-exposed population in Portugal. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:960-970. [PMID: 21707421 DOI: 10.1080/15287394.2011.582024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A wide range of chemical products known to be acutely toxic is currently used in the agricultural sector, including numerous pesticides with different compositions. Nevertheless, the effects in human health as result of chronic exposure to low levels are not yet completely understood. The methodology for determination of micronuclei (MN) in lymphocytes (CBMN) is well established, and accumulating data demonstrated a correlation to enhanced risk of cancer development. However, analysis of MN in reticulocytes (MN-RET) in humans is a recent tool on human biomonitoring. The aim of this study was to examine the influence of pesticide exposure on MN-RET and CBMN frequencies. In total, 177 individuals were studied (93 controls and 84 exposed). All individuals included in the exposed group were exposed regularly to various chemicals. Both MN-RET and CBMN were significantly higher in the exposed subjects compared to controls. The CBMN frequencies were quantitatively higher in females than males, especially within the exposed group. Smoking habits exerted no marked influence on the frequency of the biomarkers studied. A significant and positive correlation was found between both indicators. Within the exposed group, data showed that there was a significant correlation between MN-RET and recent exposure (exposure in the previous 10 d) that is not found when considering CBMN. It is conceivable that due to the short life span of reticulocytes, MN-RET were found to be more reliable to characterize recent genetic damage as opposed to CBMN.
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Affiliation(s)
- Carla Costa
- National Institute of Health, Environmental Health Department, Porto, Portugal.
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19
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Dertinger SD, Torous DK, Hayashi M, MacGregor JT. Flow cytometric scoring of micronucleated erythrocytes: an efficient platform for assessing in vivo cytogenetic damage. Mutagenesis 2010; 26:139-45. [DOI: 10.1093/mutage/geq055] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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20
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Sun H, Tsai Y, Nowak I, Dertinger SD, Wu JHD, Chen Y. Response kinetics of radiation-induced micronucleated reticulocytes in human bone marrow culture. Mutat Res 2010; 718:38-43. [PMID: 21056116 DOI: 10.1016/j.mrgentox.2010.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 12/01/2022]
Abstract
The frequency of micronucleated reticulocytes (MN-RETs) in the bone marrow or peripheral blood is a sensitive indicator of cytogenetic damage. While the kinetics of MN-RET induction in rodent models following irradiation has been investigated and reported, information about MN-RET induction of human bone marrow after radiation exposure is sparse. In this report, we describe a human long-term bone marrow culture (LTBMC), established in three-dimensional (3D) bioreactors, which sustains long-term erythropoiesis. Using this system, we measured the kinetics of human bone marrow red blood cell (RBC) and reticulocyte (RET) production, as well as the kinetics of human MN-RET induction following radiation exposure up to 6Gy. Human bone marrow established in the 3D bioreactor demonstrated an average percentage of RBCs among total viable cells peaking at 21% on day 21. The average percentage of RETs among total viable cells reached a maximum of 11% on day 14, and remained above 5% by day 28, suggesting that terminal erythroid differentiation was still active. Time- and dose-dependent induction of MN-RET by gamma radiation was observed in the human 3D LTBMC, with peak values occurring at approximately 3 days following 1Gy irradiation. A trend towards delayed peak to 3-5 days post-radiation was observed with radiation doses ≥2Gy. Our data reveal valuable information on the kinetics of radiation-induced MN-RET of human bone marrow cultured in the 3D bioreactor, a synthetic bioculture system, and suggest that this model may serve as a promising tool for studying MN-RET formation in human bone marrow, thereby providing opportunities to study bone marrow genotoxicity testing, mitigating agent effects, and other conditions that are not ordinarily feasible to experimental manipulation in vivo.
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Affiliation(s)
- Hongliang Sun
- Department of Radiation Oncology, University of Rochester Medical Center, 601 Elmwood Ave, Box 647, Rochester, NY 14642-8647, United States.
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21
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Heddle JA, Fenech M, Hayashi M, MacGregor JT. Reflections on the development of micronucleus assays. Mutagenesis 2010; 26:3-10. [PMID: 20980366 DOI: 10.1093/mutage/geq085] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
These are personal reflections on the development of methods to use micronuclei as a measure of genetic damage and their use in research and in toxicology by four people who have been intimately involved with this work, a personal rather than a comprehensive history. About 6000 papers have been published using such methods in many tissues in vivo or in cultured cells of many organisms from plants to humans, but the majority of the work has been on mammalian erythrocytes and human lymphocytes, the areas in which we have worked primarily. Although this is by no means a complete history, those working in the field may be interested in some of the personal events that lie behind the development and acceptance of methods that are now standard.
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Affiliation(s)
- John A Heddle
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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Recio L, Hobbs C, Caspary W, Witt KL. Dose-response assessment of four genotoxic chemicals in a combined mouse and rat micronucleus (MN) and Comet assay protocol. J Toxicol Sci 2010; 35:149-162. [PMID: 20371966 PMCID: PMC3520611 DOI: 10.2131/jts.35.149] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2024]
Abstract
The in vivo micronucleus (MN) assay has proven to be an effective measure of genotoxicity potential. However, sampling a single tissue (bone marrow) for a single indicator of genetic damage using the MN assay provides a limited genotoxicity profile. The in vivo alkaline (pH >13) Comet assay, which detects a broad spectrum of DNA damage, can be applied to a variety of rodent tissues following administration of test agents. To determine if the Comet assay is a useful supplement to the in vivo MN assay, a combined test protocol (MN/Comet assay) was conducted in male B6C3F1 mice and F344/N rats using four model genotoxicants: ethyl methanesulfonate (EMS), acrylamide (ACM), cyclophosphamide (CP), and vincristine sulfate (VS). Test compounds were administered on 4 consecutive days at 24-hr intervals (VS was administered to rats for 3 days); animals were euthanized 4 hr after the last administration. All compounds induced significant increases in micronucleated reticulocytes (MN-RET) in the peripheral blood of mice, and all but ACM induced MN-RET in rats. EMS and ACM induced significant increases in DNA damage, measured by the Comet assay, in multiple tissues of mice and rats. CP-induced DNA damage was detected in leukocytes and duodenum cells. VS, a spindle fiber disrupting agent, was negative in the Comet assay. Based on these results, the MN/Comet assay holds promise for providing more comprehensive assessments of potential genotoxicants, and the National Toxicology Program (NTP) is presently using this combined protocol in its overall evaluation of the genotoxicity of substances of public health concern.
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Affiliation(s)
- Leslie Recio
- Genetic Toxicology Division, ILS, Inc., PO Box 13501, RTP, NC 27709
| | - Cheryl Hobbs
- Genetic Toxicology Division, ILS, Inc., PO Box 13501, RTP, NC 27709
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Assessment of genotoxicity associated with hydroxyurea therapy in children with sickle cell anemia. Mutat Res 2010; 698:38-42. [PMID: 20230905 DOI: 10.1016/j.mrgentox.2010.03.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 11/22/2022]
Abstract
Hydroxyurea induces fetal hemoglobin, improves laboratory parameters, and ameliorates clinical complications of sickle cell anemia (SCA), but its long-term efficacy and safety in this patient population remain incompletely defined. Although generally considered non-DNA reactive, an important safety concern is that hydroxyurea may indirectly cause genotoxic damage. To better address this safety issue of hydroxyurea in patients with SCA, we measured the production of micronuclei (MN) in red blood cells (RBCs) as a marker of genotoxicity. Blood samples were collected from children with SCA enrolled in the Hydroxyurea Study of Long-term Effects (ClinicalTrials.gov NCT00305175). Flow cytometry quantified circulating MN-containing erythrocyte sub-populations before and during hydroxyurea exposure. The frequency of micronucleated reticulocytes (MN-CD71(+)) and micronucleated mature erythrocytes (MN-RBC) was then tested for associations with laboratory and clinical data. In cross-sectional analysis of 293 blood samples from 105 children with SCA and a median of 2 years of hydroxyurea therapy, exposure to hydroxyurea was associated with significantly increased frequencies of MN-CD71(+) and MN-RBC compared to baseline. The increases were evident by 3 months of therapy, and did not escalate further with up to 12 years of continuous drug exposure. In prospective longitudinal analysis, substantial inter-individual variation in the effect of hydroxyurea on %MN-CD71(+) was observed that was associated with the expected laboratory effects of hydroxyurea. In conclusion, clinically relevant exposure to hydroxyurea is associated with increased MN production consistent with erythroblast genotoxicity but with substantial inter-patient variability. Associations between increased %MN-CD71(+) and laboratory benefits suggest that hydroxyurea effects on MN production may be related to individual patient sensitivity to hydroxyurea within the bone marrow.
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Chen Y, Tsai Y, Nowak I, Wang N, Hyrien O, Wilkins R, Ferrarotto C, Sun H, Dertinger SD. Validating high-throughput micronucleus analysis of peripheral reticulocytes for radiation biodosimetry: benchmark against dicentric and CBMN assays in a mouse model. HEALTH PHYSICS 2010; 98:218-227. [PMID: 20065686 DOI: 10.1097/hp.0b013e3181abaae5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Automation of radiation biodosimetry is one of the top priority tasks considered by the Office of Science and Technology Policy and the Homeland Security Council in preparation for the nation's readiness for a possible radionuclear terrorist attack. The Center for Biophysical Assessment and Risk Management Following Irradiation, a consortium of researchers and institutions centered at the University of Rochester, has been investigating automated scoring of radiation-induced micronucleus formation in reticulocytes for high-throughput radiation biodosimetry. The collaborative project is based on a commercially-available product by Litron Laboratories in Rochester, New York. The study was designed to validate the flow-cytometry based analysis of micronucleated reticulocyte expression for radiation biodosimetry by benchmarking against the standard lymphocyte-based biodosimetry methods in a mouse model. C57B1/6 mice and C3H mice were exposed to Cs total-body radiation from 0-3 Gy. Blood samples were subsequently analyzed for CD71+ micronucleated reticulocyte and reticulocyte frequencies by flow cytometry. Results showed a linear dose-response of MN-RET up to 1 Gy for C57B1/6 and 2 Gy for C3H mice. On the other hand, robust and good dose-response curves were obtained with lymphocyte-based dicentric assay and cytokinesis-block micronucleus assay up to 3 Gy. High-throughput, automated analyses of micronucleated reticulocytes is a sensitive and reproducible method for detecting recent radiation exposure. In mice, the dose range of detection is useful up to 1 Gy (C57Bl/6) and 2 Gy (C3H) but not reliable beyond these dose limits. The utilization of this automated analysis for human radiation biodosimetry is currently under investigation.
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Affiliation(s)
- Yuhchyau Chen
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Elespuru RK, Agarwal R, Atrakchi AH, Bigger CAH, Heflich RH, Jagannath DR, Levy DD, Moore MM, Ouyang Y, Robison TW, Sotomayor RE, Cimino MC, Dearfield KL. Current and Future Application of Genetic Toxicity Assays: The Role and Value of In Vitro Mammalian Assays. Toxicol Sci 2009; 109:172-9. [DOI: 10.1093/toxsci/kfp067] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
Over the past five decades, those interested in markers of radiation effect have focused primarily on tumor response. More recently, however, the view has broadened to include irradiated normal tissues-markers that predict unusual risk of side-effects, prognosticate during the prodromal and therapeutic phases, diagnose a particular toxicity as radiation-related, and, in the case of bioterror, allow for tissue-specific biodosimetry. Currently, there are few clinically useful radiation-related biomarkers. Notably, levels of some hormones such as thyroid-stimulating hormone (TSH) have been used successfully as markers of dysfunction, indicative of the need for replacement therapy, and for prevention of cancers. The most promising macromolecular markers are cytokines: TGFbeta, IL-1, IL-6, and TNFalpha being lead molecules in this class as both markers and targets for therapy. Genomics and proteomics are still in nascent stages and are actively being studied and developed.
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Affiliation(s)
- Paul Okunieff
- Department of Radiation Oncology, James P. Wilmot Cancer Center, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 647, Rochester, NY 14642, USA.
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Differences in the frequency of micronucleated erythrocytes in humans in relation to consumption of fried carbohydrate-rich food. Mutat Res 2008; 653:50-6. [PMID: 18485803 DOI: 10.1016/j.mrgentox.2008.03.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 02/08/2008] [Accepted: 03/12/2008] [Indexed: 11/21/2022]
Abstract
The aim of this study was to investigate if consumption of ordinary carbohydrate-rich food prepared in different ways has an impact on chromosome stability, i.e., on the formation of micronucleated young erythrocytes in humans. Twenty-four persons, divided into two groups, participated during 4 days in a semi-controlled food-consumption study. One group (low-heated-food-group, LowHF-group) consumed only food boiled in water (max 100 degrees C) and the other group (high-heated-food-group, HighHF-group) consumed preferentially strongly heated (fried) food. From each of the subjects, blood samples were drawn, before and after 4 days. The frequency (f) of micronucleated (MN) very young erythrocytes (transferrin-positive reticulocytes, Trf-Ret), fMNTrf-Ret, was determined, and the difference in the frequency, before and after the eating period, was calculated. The obtained mean differences for the two groups were compared. As an indicator of highly heated food the acrylamide (AA) content in part of the consumed foodstuffs was analysed by use of LC/MS-MS and the AA intake estimated. In the blood samples the hemoglobin-adduct levels from AA were analysed as a measure of the internal AA dose. The differences between the mean fMNTrf-Ret, before and after the eating period, were -0.15 per thousand for the LowHF-group and +0.17 per thousand for the HighHF-group, p<0.005 (t-test, one-tailed). The mean total AA intake in the HighHF-group during 4 days was estimated to about 3000+/-450microg per person. For the LowHF-group, the mean AA intake was low, 20+/-10microg per person. The lowest dose of AA that caused a significant increase of micronucleated erythrocytes in mice is more than a hundred times higher than the AA level in this study. Thus, it is unlikely that the exposure to AA is the major cause behind the observed difference. The answer is probably to be found in other compounds produced at the same time during heating of the food.
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28
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Nakachi K, Hayashi T, Hamatani K, Eguchi H, Kusunoki Y. Sixty years of follow-up of Hiroshima and Nagasaki survivors: current progress in molecular epidemiology studies. Mutat Res 2008; 659:109-17. [PMID: 18406659 DOI: 10.1016/j.mrrev.2008.02.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 01/30/2008] [Accepted: 02/04/2008] [Indexed: 11/26/2022]
Abstract
This article provides an overview of the on-going molecular epidemiology studies among atomic-bomb survivors conducted at the Radiation Effects Research Foundation in Japan. The focus is on: (a) inter-individual variations in sensitivity to radiation-induced somatic mutations (glycophorin A (GPA) mutations) and their potential relevance to differences in susceptibility to radiation-related cancers and (b) the role of specific mutations/rearrangements in radiation-induced thyroid and colorectal cancers. The glycophorin A mutant fractions showed large differences between the survivors at each of the estimated bone marrow doses. Of note is the finding at doses>or=1 Gy; that the slope of the mutant fraction was significantly higher in the 'cancer group' than in the 'non-cancer group'. This study provided the basis for validating the use of gammaH2AX and reticulocyte micronucleus assays for evaluating radiosensitivity differences and genetic instability, respectively, in our studies in the coming years. Preliminary results from our molecular oncology studies on adult-onset papillary thyroid cancer provide evidence for the induction of RET/PTC rearrangements and BRAF point mutation (both known to be early stage events in adult-onset papillary thyroid cancer) but with a difference: cases associated with the rearrangements were more frequent at high doses, and developed sooner than those with BRAF mutation. In the case of colorectal cancer, the results suggest that radiation exposure might influence microsatellite instability (MSI) status through MSI-related epigenetic and genetic alterations-processes that might occur in the early stage of colorectal carcinogenesis.
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Affiliation(s)
- Kei Nakachi
- Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation (RERF), 5-2 Hijiyama Park, Minami-ku, Hiroshima-shi, Hiroshima 732-0815, Japan.
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Hotchkiss CE, Bishop ME, Dertinger SD, Slikker W, Moore MM, Macgregor JT. Flow cytometric analysis of micronuclei in peripheral blood reticulocytes IV: an index of chromosomal damage in the rhesus monkey (Macaca mulatta). Toxicol Sci 2008; 102:352-8. [PMID: 18211907 DOI: 10.1093/toxsci/kfn013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We report evaluation in rhesus monkeys of a flow cytometric procedure (MicroFlow) that has previously been shown to allow assessment of micronucleated reticulocytes (MN-RETs) in the peripheral blood of rats and dogs. Reticulocytes (RETs) were labeled with anti-CD71-fluorescein isothiocyanate, DNA was stained with propidium iodide using RNase treatment, and anti-CD61-phycoerythrin was used to reduce interference from platelets. Flow cytometric data were compared with microscopic scores of peripheral blood and bone marrow using standard acridine orange staining. A single iv administration of cyclophosphamide (CP, 5 mg/kg) induced an approximately 10-fold increase in blood MN-RET frequency, with the peak occurring 2 days after administration. After daily CP treatment to approximate a steady-state condition, the frequency of MN-RETs in peripheral blood was approximately 25% of that in bone marrow, indicating strong selection against MN-RETs. Nonetheless, CP-treated animals exhibited markedly elevated blood MN-RET values (2.45-3.99%, n = 3; compared to a mean baseline of 0.12%, n = 6). These measurements closely reflected the increased frequencies observed in the bone marrow compartment (Spearman correlation coefficient = 0.9856, n = 6). These data suggest that MN-RET measurements in blood are suitable for assessing chemical-induced chromosomal damage and can be readily integrated into routine toxicity tests, allowing genotoxicity data to be obtained as an integral part of toxicity evaluations. Microscopy-based scoring is challenging due to the low frequency of RETs and MN-RET in monkeys, but sufficient numbers of cells are easily scored with the flow cytometric procedure.
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Harper SB, Dertinger SD, Bishop ME, Lynch AM, Lorenzo M, Saylor M, MacGregor JT. Flow Cytometric Analysis of Micronuclei in Peripheral Blood Reticulocytes III. An Efficient Method of Monitoring Chromosomal Damage in the Beagle Dog. Toxicol Sci 2007; 100:406-14. [PMID: 17872896 DOI: 10.1093/toxsci/kfm241] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Erythrocyte-based micronucleus tests have traditionally analyzed bone marrow because splenic filtration in most species removes micronucleated cells from peripheral blood. We have evaluated a flow cytometric method for monitoring micronucleated reticulocyte frequencies (%MN-RET) in the peripheral blood of beagle dogs treated with cyclophosphamide (CP) and have found that analysis of micronucleated reticulocytes (MN-RETs) in peripheral blood is a suitable surrogate for bone marrow analysis. The three-color flow cytometric method uses anti-CD71 labeling to identify reticulocytes and Plasmodium berghei-containing erythrocytes as a calibration standard. The spontaneous %MN-RET determined by flow cytometry was 0.31 +/- 0.09% (n = 22) for peripheral blood, compared with 0.38 +/- 0.13% (SD, n = 12) for bone marrow, and 0.27 +/- 0.08% (n = 12) for peripheral blood by microscopic scoring with acridine orange staining. The kinetics of appearance and disappearance of MN-RETs in blood were determined by collecting daily samples after iv treatment with CP. The maximum frequency occurred approximately 48 h after dosing. Frequencies of MN-RETs in peripheral blood at steady state following daily CP treatment were 55-68% of corresponding bone marrow values assessed by microscopy and 55-112% as assessed by flow cytometry. This difference is presumably due to splenic removal, which appears slightly less stringent than that previously reported for CP-treated Sprague-Dawley rats. Responses in bone marrow and peripheral blood were highly correlated and similar to or greater than those reported in mice and rats at equitoxic doses.
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Affiliation(s)
- Susan B Harper
- Department of Veterans Affairs, Washington, DC 20422, USA
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Witt KL, Cunningham CK, Patterson KB, Kissling GE, Dertinger SD, Livingston E, Bishop JB. Elevated frequencies of micronucleated erythrocytes in infants exposed to zidovudine in utero and postpartum to prevent mother-to-child transmission of HIV. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:322-9. [PMID: 17358032 PMCID: PMC1906863 DOI: 10.1002/em.20266] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Zidovudine-based antiretroviral therapies (ARTs) for treatment of HIV-infected pregnant women have markedly reduced mother-to-child transmission of the human immunodeficiency virus (HIV-1) from approximately 25% to <1%. However, zidovudine (ZDV; AZT), a nucleoside analogue, induces chromosomal damage, gene mutations, and cancer in animals following direct or transplacental exposure. To determine if chromosomal damage is induced by ZDV in infants exposed transplacentally, we evaluated micronucleated reticulocyte frequencies (%MN-RET) in 16 HIV-infected ART-treated mother-infant pairs. Thirteen women received prenatal ART containing ZDV; three received ART without ZDV. All infants received ZDV for 6 weeks postpartum. Venous blood was obtained from women at delivery and from infants at 1-3 days, 4-6 weeks, and 4-6 months of life; cord blood was collected immediately after delivery. Ten cord blood samples (controls) were obtained from infants of HIV-uninfected women who did not receive ART. %MN-RET was measured using a single laser 3-color flow cytometric system. Tenfold increases in %MN-RET were seen in women and infants who received ZDV-containing ART prenatally; no increases were detected in three women and infants who received prenatal ART without ZDV. Specifically, mean %MN-RET in cord blood of ZDV-exposed infants was 1.67 +/- 0.34 compared with 0.16 +/- 0.06 in non-ZDV ART-exposed infants (P = 0.006) and 0.12 +/- 0.02 in control cord bloods (P < 0.0001). %MN-RET in ZDV-exposed newborns decreased over the first 6 months of life to levels comparable to cord blood controls. These results demonstrate that transplacentalZDV exposure is genotoxic in humans. Long-term monitoring of HIV-uninfected ZDV-exposed infants is recommended to ensure their continued health.
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Affiliation(s)
- Kristine L. Witt
- National Toxicology Program, National Institute of Environmental Health Sciences, RTP, NC
| | | | | | - Grace E. Kissling
- National Toxicology Program, National Institute of Environmental Health Sciences, RTP, NC
| | | | | | - Jack B. Bishop
- National Toxicology Program, National Institute of Environmental Health Sciences, RTP, NC
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