Análisis citogenético en linfocitos de trabajadores expuestos a radiación ionizante en una unidad de cardiología intervencional de Chile: estudio piloto y revisión de la literatura / Citogenetic effects upon lymphocyes in subjects exposed to ionizing radiadion in an interventional laboratory cardiology: pilot study and literature review

ANTECEDENTES: Un número creciente de artículos está llamando la atención en forma consistente sobre la eventual asociación que existe entre los denominados trabajadores ocupacionalmente expuestos a bajos niveles de radiación ionizante (POEs) y una mayor frecuencia de aberraciones cromosómicas, a nivel Sudamericano estos estudios son escasos. OBJETIVO: Evaluar la frecuencia de aberraciones cromosómicas en linfocitos de sangre periférica de POEs de un hospital y de sujetos sanos. Adicionalmente, se realizó una revisión exhaustiva de los artículos que a la fecha abordaron este tema. MATERIAL Y MÉTODO: Se condujo un análisis citogenético destinado a cuantificar las aberraciones cromosómicas en sangre periférica de linfocitos de 6 POEs de la unidad de Cardiología Intervencional y, como controles, 6 muestras de sujetos de la población general fueron analizadas. RESULTADOS: Se observó un importante contraste en el número de aberraciones cromosómicas presentadas en los POEs versus la población general no expuesta a radiaciones ionizantes, siendo esta de una relación de 6:1, respectivamente. CONCLUSIÓN: Los resultados preliminares indican una mayor frecuencia de aberraciones cromosómicas en los POEs versus la población general, sin embargo, se deberá esperar los resultados de la segunda fase de investigación, donde al ampliar la muestra en análisis se podrán obtener conclusiones estadísticamente significativas.

BACKGROUND: There is growing evidence of an increased number of chromosomes aberrations in subjects exposed to low levels of ionizing radiation (POEs). There are few studies on this subject in Latin America AIM: To evaluate the frequency of chromosome aberrations in lymphocytes obtained from peripheral blood in subjects working in laboratories where low levels of ionizing radiation are present and to compare these findings to those of unexposed subjects. METHODS: A cytogenic analysis to quantify chromosome aberrations was performed in 6 POs subjects from a cardiology invasive laboratory and 6 controls from a general unexposed population. RESULTS: Compared to controls, an approximately 6-fold increase in the number of chromosome aberrations was observed.in subjects exposed to ionizing radiation CONCLUSION: These preliminary results indicate that there is an increased number of chromosome aberrations in subjects exposed to low levels of ionizing radiation, as occurs in people working in a cardiology interventional laboratory. Studies in large numbers of subjects and preferably followed prospectively are needed to evaluate more precisely this effect.

Construction of a dose- response curve by induction of premature chromosome condensation for biological dosimetry

Premature Chromosome Condensation [PCC] appears to have a possible utility for biological dosimetry purposes. The PCC technique may be adapted for cases of suspicion of overexposure where sampling is performed at least one day after an accident. For this purpose, human blood samples were exposed in vitro to [60] Co up to 10 Gy and the PCC technique was performed immediately after irradiation. Analysis of excess PCC fragments distribution showed an over dispersion and the dose-effect relationship was best characterized by linear regression

[Cytological radiotoxicity of radioiodine therapy in patients with differentiated thyroid carcinoma]

Cytological radiation damage to lymphocytes can result in augmentation of cells with micronuclei. In this study we investigated Cytological radiation damage to peripheral blood lymphocytes using the micronuclei assay [MNA] method. Considering the value of Iodine-131 in diagnostic and therapeutic nuclear medicine and high absorbed dose of I131 radioiodine in comparison with gamma emitters and the effect of type of radiation, dose and species on radiosensitivity of patients, this study was conducted. To evaluating the Cytological radiotoxicity of therapeutic radiotracers such as radioiodine I131. We studied 22 patients with differential thyroid carcinoma who were referred for treatment with 100 or 150 mci I131. Before and one weak after treatment the peripheral lymphocytes were harvested and isolated by a Cytological method and assayed for frequency of micronuclei as a marker of Cytological radiotoxicity. The means of micronuclei in one hundred binuclear lymphocytes were 6.3 +/- 2.2 before treatment and 9.6 +/- 3.1 after treatment, differences in the number of micronuclei being statistically significant [p value <0.05]. High doses of radioiodine therapy used after surgery for differentiated thyroid carcinoma can increase micronuclei among peripheral lymphocytes as an indirect marker of chromosomal aberrations and cytotoxic radiation damage

Frequencies of Micronuclei in Peripheral Lymphocytes in Korean Populations after Chronic Low-dose Radiation Exposure

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.

Effect of diagnostic X-rays on somatic chromosomes of occupationally exposed workers.

Investigations were carried out to estimate the level of radiation exposure effect of X-ray machines on 40 male personnel handling diagnostic X-ray machines and compared to 38 matched, unexposed, normal controls. The actual accumulated radiation doses were not disclosed. As compared to controls the exposed persons showed highly significantly increased levels (P < 0.01) of chromosome aberrations (0.68%-2.67%). Frequencies of sister chromatid exchanges (5.80-6.20) and the levels of aneuploidy (2.27-2.37) were also increased a little, but did not show statistically significant effect of exposure. Satellite associations (7.84-16.25) and mitotic index (5.14-6.07) showed a significant increase (P < 0.05) in exposed individuals. The statistically significant increase in the frequencies of chromosomal aberrations and satellite associations in X-ray personnel underscores the need of adopting measures to avoid or at least minimiZe overexposure to X-irradiation.