ABSTRACT
Resumen Introducción: el laboratorio de citogenética del Instituto de Investigaciones en Salud (INISA) de la Universidad de Costa Rica estableció un Servicio de Dosimetría Biológica en enero del 2020 utilizando biomarcadores citogenéticos de exposición a radiaciones ionizantes. Es el primero de su tipo en la región centroamericana. Objetivo: establecer un servicio de dosimetría biológica para Costa Rica, elaborando una curva de calibración dosis-efecto para rayos gamma. Metodología: para la realización de la curva de calibración se irradiaron muestras de sangre periférica in vitro con rayos gamma de dos voluntarios, uno femenino y otro masculino, en 11 puntos de dosis en el rango de 0 a 5 Gy. Se cultivó la sangre acorde a los protocolos internacionales durante 48 horas y se registraron las aberraciones inducidas. Los programas Dose Estimate V5.2 y R versión 4.03 se utilizaron para el cálculo de los coeficientes de la curva de calibración que correlaciona la frecuencia de cromosomas dicéntricos con la dosis. Resultados: los coeficientes de la curva son α: 0.02737±0.00658, ß: 0,05938±0,00450 y C: 0.00129±0.00084. Estos coeficientes tienen valores similares a los reportados internacionalmente. La curva se validó calculando dos dosis incógnitas, en la primera incógnita la dosis suministrada fue de 1,5 Gy y la dosis estimada fue 1,47 Gy y en la segunda la dosis suministrada fue de 4 Gy y la dosis estimada fue 3,616 Gy, para ambos casos no existen diferencias estadísticamente significativas entre las dosis suministradas y las estimadas. Conclusiones: actualmente El Servicio de Dosimetría Biológica del INISA puede estimar dosis absorbida en personas que se sospecha de una sobre exposición a rayos gamma en personal ocupacionalmente expuesto o personas involucradas en un accidente radiológico.
Abstract Introduction. The cytogenetics laboratory of the Health Research Institute (INISA) of the University of Costa Rica established a Biological Dosimetry Service in January 2020 using cytogenetic biomarkers of exposure to ionizing radiation. It is the first of its kind in the Central American region. Objective: establish a biological dosimetry service for Costa Rica, developing a dose-effect calibration curve for gamma rays. Methodology: to carry out the calibration curve, peripheral blood samples from two volunteers, one female and the other male, were irradiated in vitro with gamma rays, at 11 dose points in the range of 0 to 5 Gy. Blood was cultured according to international protocols for 48 hours and induced aberrations were recorded. The Dose Estimate V5.2 and R version 4.03 programs were used to calculate the coefficients of the calibration curve that correlates the frequency of dicentric chromosomes with the dose. Results: the coefficients of the curve are α: 0.02737 ± 0.00658, ß: 0.05938 ± 0.00450 and C: 0.00129 ± 0.00084. These coefficients have values similar to those reported internationally. The curve was validated by calculating two unknown doses, in the first unknown case the delivered dose was 1.5 Gy and the estimated dose was 1.47 Gy and in the second case the delivered dose was 4 Gy and the estimated dose was 3.616 Gy. for both cases there are no statistically significant differences between the delivered and estimated doses. Conclusions: the Biological Dosimetry Service of the INISA can estimate absorbed dose in persons suspected of overexposure to gamma rays in occupationally exposed personnel or persons involved in a radiological accident.Health is loaded with symbolisms and practical manifestations that differ according to social groups and sociocultural contexts. In order to make everyday life and needs visible, the Theoretical Paradigm of Social Representations provides the theoretical-methodological bases necessary to understand the common sense knowledge associated with health among the Nicaraguan migrant population in Costa Rica. Methodology: Qualitative study with ethnographic approach that aimed to identify the social representation of health, through the process of objectification, present among Nicaraguan migrants living in Costa Rica. Data collected through semi-structured interviews, participant observation, and field diaries. Processing according to Content Analysis. Results: The social representation of health found behaves analogously to a formula; where, the search for peaceful environments is added to the achievement of financial stability to result in two interdependent representations: 1) Health as physical-mental strength; and 2) Health as a future and abstract sensation of well-being, happiness and transcendence. The socio-political antecedents in Nicaragua, the migratory process, and the adaptation to Costa Rica play a preponderant role in shaping the representation on health. Conclusion: Social representations about health have direct practical implications on the ways of life and needs of migrant groups. Understanding their common sense knowledge allows to move towards more contextualized public policies. More integration of the thoughts, opinions and feelings of migrants in decision-making platforms is recommended.
Subject(s)
Humans , Male , Female , Radiation, Ionizing , Dosimetry , Costa Rica , Gamma RaysABSTRACT
Objective To investigate a dose response curve based on a genetic workstation with automatic analysis system of dicentric chromosome assay (DCA) for establishing a high speed dose estimation method.Methods Peripheral blood from three healthy volunteers was irradiated in vitro using 60Co γ-rays,and then lymphocytes were cultured and fixed on slides using the standard protocol for DCA.Dicentric chromosome in metaphase cells was analyzed automatically with the genetic workstation and confirmed manually,and the dose response curve of automated dicentric chromosome was fitted.Dicentric chromosome of another peripheral blood sample irradiated with different doses was manually analyzed to verify the accuracy of the above automated DCA.Results The yield of automated DCA was well fitted by an equation Y =0.018 06D2 + 0.012 79D + 0.000 489 1 with a correlation coefficient R2 =0.961.The biological dose of radiation could be accurately estimated by this dose response curve within a few minutes.Conclusions We had successfully established a new dosimetry method by analyzing dicentric chromesome automatically,which can save a lot of manual analysis time and hence has important significance for emergency rescue in nuclear accidents.
ABSTRACT
La biodosimetría citogenética se aplica en la evaluación médica de las personas involucradas en situaciones radiológicas anormales, con el fin de evaluar las dosis recibidas, el peligro inminente para la salud y aplicar los tratamientos médicos más adecuados. Además, contribuye al esclarecimiento de sucesos cuando existen dudas respecto a los resultados de la dosimetría física por dosímetros defectuosos, no calibrados o ausentes. Es el método más preciso de dosimetría biológica, ya que existe una relación matemática que permite calcular la dosis, establecer el grado de homogenidad de la exposición y, en caso de exposiciones no homogéneas, establecer la fracción del cuerpo irradiada y la dosis que recibió esa fracción mediante la cuantificación del número y tipos de aberraciones cromos¢micas y de micronúcleos y su distribución en los linfocitos de la sangre periférica. Para este análisis se establecen las relaciones dosis-efecto y un sistema automatizado para el cálculo de las dosis de radiación recibidas. Actualmente se está desarrollando un proyecto conjunto Universidad de Costa Rica-Hospital San Juan de Dios, con el objetivo de explorar los efectos cromosómicos de la radiación, en pacientes expuestos por razones el objetivo de explorar los efectos cromosómicos de la radiación, en pacientes expuestos por razones terapéuticas y atendidos en este hospital. De igual modo, se hará la curva de calibración dosis-respuesta in vitro para rayos gama y se validar mediante la intercomparación con el Laboratorio de Dosimetría Citogenética de Centro para la Protección e Higiene de las Radiaciones de Cuba...
Subject(s)
Humans , Cytogenetics , Radioactive Hazard Release/classification , Radiation Exposure , Radiation, Ionizing , Radiobiology , RadiometryABSTRACT
The prognosis and medical handling of individuals exposed to external radiation depend upon whether the whole body has been exposed, or the exposure was localized. It is very important for the prognosis and choice of treatment to know how the absorbed dose has been distributed within the body. The dose distribution depends on the condition of exposure and the circumstances of the accident. Local radiation injury (LRI) is much more frequent than whole body exposure (WBE) and hence described in detail in a variety of literature. LRI caused by high doses of radiation (> or = 8~10 Gy) produces signs and symptoms similar to a thermal burn except for the striking delay in the onset of clinical changes, from several days to a week or longer. The severity of LRI depends not only on the dose and type of radiation, but also on the location and size of the area exposed. In general, the higher the dose received, the more rapid the development of pathological symptoms and the more severe the prognosis. Therefore, diagnosis and prognosis should be based upon various parameters, besides the clinical observation, such as dosimetry, reconstruction of the accident, thermography, scintigraphy, etc.
Subject(s)
Burns , Diagnosis , Prognosis , Radiation Injuries , Radionuclide Imaging , Strikes, Employee , ThermographyABSTRACT
The purpose of this study was to estimate predictive markers of intrinsic radiosensitivity in individuals who were exposed to occupational or environmental radiation. Throughout this process, the actual biohazard risks and base-line chromosome damage were evaluated in human population. Further studies were carried out to provide evidence for the existence of individual variations in age-dependent responses through micronuclei (MN) assay.Spontaneous frequencies not only vary greatly between individuals, but also working or living areas. It was shown that the increased level of spontaneous cell with MN was observed with increasing age. The relationship between radiosensitivity and the increased spontaneous level of MN may be in an inverse proportion. Ionizing radiation may be targeted mutagenic effects at the usual exposures of background levels that populations were exposed. Age and gender are the most important demographic variables in determining the MN index with frequencies in females, which were greater than those in males. The main life-style factors influencing the MN index in subjects were correlated significantly and positively with smoke. The results showed that an indicator of the genetic damaged rate in MN index in human populations significantly correlated with age, sex and life-style factors. So far, it is evident that with regard to the application of MN assay all future studies have to take into account the influence of age, gender, and life-style.In Conclusion, using micronuclei assay technique a large population can be easily monitored. This study illustrated that the MN assay may provide a high potential to ensure appropriate quality control and standard documentation protocol that can be used to monitor a large population exposed to radiation epidemiologically.
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Age Factors , Background Radiation/adverse effects , Chromosomes, Human/radiation effects , Environmental Exposure/adverse effects , Korea , Life Style , Lymphocytes/radiation effects , Micronuclei, Chromosome-Defective/radiation effects , Micronucleus Tests , Occupational Exposure/adverse effects , Radiation Tolerance/physiology , Sex FactorsABSTRACT
PURPOSE: It was studied that the relationship between radiation dose, dose rate and the frequency of chromosomal aberrations in peripheral lymphocytes. METHODS AND MATERIALS: Peripheral lymphocytes were irradiated in vitro with 6 MeV X-ray at dose ranges from 50 cGy to 800 cGy. The variations of the frequency of chromosomal aberrations were observed according to different radiation dose rate from 20 cGy/min to 400 cGy/min at constant total dose of 400 cGy which it was considered as factor to correct biological radiation dose measurement. RESULTS: The yields of lymphocytes with chromosomal aberrations (dicentric chromosome, ring chromosome, acentric fragment pairs) are 0% at 50 cGy, 9% at 100 cGy, 20% at 200 cGy, 27% at 300 cGy, 55% at 400 cGy, 88% at 600 cGy, and 100% at 800 cGy. The value of Ydr is 0.000 at 50 cGy, 0.093 at 100 cGy, 0.200 at 200 cGy, 0.364 at 300 cGy, 0.612 at 400 cGy, 2.040 at 600 cGy, and 2.846 at 800 cGy. The relationship between radiation (D) and the frequency of dicentric chromosomes and ring chromosomes (Ydr) can be expressed as Ydr=0.188x10-2/GyxD+0.422x10-4/Gy2xD2. The value of Qdr is 0.000 at 50 cGy, 1.000 at 100 cGy, 1.000 at 200 cGy, 1.333 at 300 cGy, 1.118 at 400 cGy, 2.318 at 600 cGy, and 2.846 at 800 cGy. When 400 cGy is irradiated with different dose rate each of 20, 40, 60, 80, 100, 160, 240, 320, and 400 cGy/min, Ydr is each of 0.982, 0.837, 0.860, 0.732, 0.763, 0.966, 0.909, 1.006, and 0.806, and Qdr is each of 1.839, 1.565, 1.654, 1.333, 1.381, 1.750, 1.6000, 1.710, and 1.318. CONCLUSION: There are not the significant variations of Ydr and Qdr values according to different dose rate. And so radiation damage is influenced by total exposed radiation doses and is influenced least of all by different dose rate when it is acute single exposure.
Subject(s)
Chromosome Aberrations , Lymphocytes , Ring ChromosomesABSTRACT
PURPOSE: The purpose of this study was to develop in vivo dosimetries using both chromosomal aberrations and micronuclei in mice to assess biological effects of radiations. MATERIALS AND METHODS: Five each mice were irradiated with 0, 1, 2, 3, 4, 5, 10 Gy of Cs-137 gamma-rays. We scored numbers of chromosomal aberrations in metaphase spreads and numbers of micronuclei in bone marrow smears under light microscope, and obtained the dose-response relationships. We also examined the relationship between the two dose-response curves. RESULTS: The frequency of both chromosomal aberrations and micronuclei increased with dose, in a linear-quadratic manner. The delta, beta, and alpha coefficients were 0.0176, 0.0324, and 0.0567 for metaphase analysis (r=1.0, p<0.001) and 0.0019, 0.0073, and 0.0506 for micronuclei assay (r=1.0, p<0.001). The frequency of chromosomal aberrations and micronuclei in diffirent radiation doses was significantly correlated (r=0.99, p<0.01). CONCLUSION: In vivo dosimetry using either metaphase analysis or micronucleus assay was feasible in mice. These methods could be useful to evaluate biological effects of radiation.
Subject(s)
Animals , Mice , Bone Marrow Cells , Bone Marrow , Chromosome Aberrations , Metaphase , Micronucleus TestsABSTRACT
PURPOSE: This study was tried to evaluate the effect of the partial body fractionated irradiation on the frequency of chromosomal aberration. MATERIALS AND METHODS: In three patients with uterine cervix carcinoma, chromosomal aberrations were analyzed during fractionated external beam radiotherapy. Radiation field included whole pelvis and total dose was 5040 cGy in 28 fractions. RESULTS: The values of the frequency of dicentrics and rings (Ydr) in pre- irradiated peripheral lymphocytes in three patients were 0.0060, 0.0000, and 0.0029, respectively. The frequency of dicentrics and rings, estimated during the course of radiotherapy, increased with radiation dose and best fitted to the linear equation, Ydr=7.31x10(-5) D(cGy)+1.45x10(-2). The frequency of dicentrics and rings among the cells with dicentric and/or ring (Qdr) also showed increasing tendency and best fitted to the linear equation, Qdr= 1.01x10(-4) D(cGy)+1.04. CONCLUSION: Ydr increased linearly with radiation dose in the dose range of our study, and Qdr showed increasing tendency with dose.
Subject(s)
Female , Humans , Cervix Uteri , Chromosome Aberrations , Lymphocytes , Pelvis , RadiotherapyABSTRACT
PURPOSE: This study was tried to evaluate the effect of the partial body fractionated irradiation on the frequency of chromosomal aberration. MATERIALS AND METHODS: In three patients with uterine cervix carcinoma, chromosomal aberrations were analyzed during fractionated external beam radiotherapy. Radiation field included whole pelvis and total dose was 5040 cGy in 28 fractions. RESULTS: The values of the frequency of dicentrics and rings (Ydr) in pre- irradiated peripheral lymphocytes in three patients were 0.0060, 0.0000, and 0.0029, respectively. The frequency of dicentrics and rings, estimated during the course of radiotherapy, increased with radiation dose and best fitted to the linear equation, Ydr=7.31x10(-5) D(cGy)+1.45x10(-2). The frequency of dicentrics and rings among the cells with dicentric and/or ring (Qdr) also showed increasing tendency and best fitted to the linear equation, Qdr= 1.01x10(-4) D(cGy)+1.04. CONCLUSION: Ydr increased linearly with radiation dose in the dose range of our study, and Qdr showed increasing tendency with dose.
Subject(s)
Female , Humans , Cervix Uteri , Chromosome Aberrations , Lymphocytes , Pelvis , RadiotherapyABSTRACT
The dose response of the number of micronuclei in cytokinesis-blocked (CB) lymphocytes after in vitro irradiation with -rays and neutrons in the 5 dose ranges was studied for a heterogeneous population of 4 donors. One thousand binucleated cells were systematically scored for micronuclei. Measurements performed after irradiation showed a dose-dependent increase in micronuclei(MN) frequency in each of the doctors studied. The dose-response curves were analyzed by a linear-quadratic model, frequencies per 1000 CB cells were (0.31+/-0.049) D+(0.0022+/-0.0002) D2+(13.19+/-1.854) (r2=1.000, X2=0.7074, p=0.95) following irradiation, and (0.99+/-0.528) D+(0.0093+/-0.0047) D2+(13.31+/-7.309) (r2=0.996, X2=7.6834, p=0.11) following neutrons irradiation (D is irradiation dose in cGy). The relative biological effectiveness (RBE) of neutrons compared with -rays was estimated by best fitting linear-quadratic model. In the micronuclei frequency between 0.05 and 0.8 per cell, the RBE of neutrons was 2.37+/-0.17. Since the MN assay is simple and rapid, it may be a good tool for evaluating the y-ray and neutron response.