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PURPOSE: This interlaboratory comparison was conducted to evaluate the performance of the Latin-American Biodosimetry Network (LBDNet) in analyzing digitized images for scoring dicentric chromosomes from in vitro irradiated blood samples. The exercise also assessed the use of weighted robust algorithms to compensate the uneven expertise among the participating laboratories. METHODS: Three sets of coded images obtained through the dicentric chromosome assay from blood samples irradiated at 1.5 Gy (sample A) and 4 Gy (sample B), as well as a non-irradiated whole blood sample (sample C), were shared among LBDNet laboratories. The images were captured using the Metafer4 platform coupled with the AutoCapt module. The laboratories were requested to perform triage scoring, conventional scoring, and dose estimation. The dose estimation was carried out using either their laboratory calibration curve or a common calibration curve. A comparative statistical analysis was conducted using a weighted robust Hampel algorithm and z score to compensate for uneven expertise in dicentric analysis and dose assessment among all laboratories. RESULTS: Out of twelve laboratories, one had unsatisfactory estimated doses at 0 Gy, and two had unsatisfactory estimated doses at 1.5 Gy when using their own calibration curve and triage scoring mode. However, all doses were satisfactory at 4 Gy. Six laboratories had estimated doses within 95% uncertainty limits at 0 Gy, seven at 1.5 Gy, and four at 4 Gy. While the mean dose for sample C was significantly biased using robust algorithms, applying weights to compensate for the laboratory's analysis expertise reduced the bias by half. The bias from delivered doses was only notable for sample C. Using the common calibration curve for dose estimation reduced the standard deviation (s*) estimated by robust methods for all three samples. CONCLUSIONS: The results underscore the significance of performing interlaboratory comparison exercises that involve digitized and electronically transmitted images, even when analyzing non-irradiated samples. In situations where the participating laboratories possess different levels of proficiency, it may prove essential to employ weighted robust algorithms to achieve precise outcomes.

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Resumen La prevalencia mundial de la discapacidad intelectual (DI) es del 3 %. Una de las causas más comunes de DI de origen genético son las aberraciones cromosómicas, las cuales resultan fácilmente detectables mediante un cariotipo. Sin embargo, muchas de estas pasan desapercibidas durante el análisis citogenético convencional debido a su tamaño. Estas pequeñas alteraciones se pueden localizar en los subtelómeros y se ha observado que, cuando es así, constituyen una razón importante de DI en pacientes que carecen de un diagnóstico de causalidad. En este estudio de tipo observacional, se utilizó la técnica MLPA con el objetivo de determinar la frecuencia de aberraciones cromosómicas submicroscópicas en los subtelómeros en una población infantil con DI de origen desconocido. Se examinaron 70 muestras de forma exitosa y se obtuvo un caso con una microduplicación en el subtelómero 17p, para una frecuencia del 1,4 %. También, se realizó el análisis citogenético en 33 muestras y se encontró un caso con una aberración cromosómica detectable al microscopio, para una frecuencia del 3 %. El porcentaje de aberraciones cromosómicas subteloméricas fue menor al esperado en comparación con estudios similares. Finalmente, se concluyó que el cariotipo y la técnica MLPA se complementan para el abordaje de personas con DI de origen desconocido.

Abstract The prevalence of intellectual disability (ID) in the global population is 3%. One of the most frequent cause of ID are chromosome aberrations, which are easily detected by a karyotype. However, many of these maygoundetected during a conventional cytogenetic analysis because of their length.These small alterations can be localized in the subtelomeres and it has been observed that when localized there, they are an important cause of ID in patients without a causality diagnostic. In this observational study, we use the MLPA technique for the purpose of identifying the frequency of submicroscopicsubtelomere chromosomal aberrations in a population of people with ID of unknown origin. 70 samples were successfully analyzed with MLPA and we found one case with a microduplication in the 17p subtelomere for a frequency of 1,4%. Also,the karyotype was performed in 33cases, and we foundone case with a chromosome aberration that can be detect by microscope for a frequency of 3%. The subtelomeric chromosome aberration frequency was lower than expected as we compare our results with similar studies. Finally, with this work we conclude that the karyotype and the MLPA technique complement each other for approaching people with ID of unknown origin.

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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.

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Particular sonographic fetal malformations are common in chromosome 18 aberrations, requiring invasive prenatal tests to confirm the diagnosis. Karyotyping is the gold standard assay in these cases, although it is a high complexity, expensive and approximately 2 weeks turnaround time test. On the contrary, quantitative fluorescent PCR is considered an accurate, simple, low cost and rapid assay, particularly useful for the diagnosis of aneuploidies of chromosomes 13, 18 and 21 and for the detection of maternal cell contamination of the sample. Clinical presentation of two cases of rare chromosome 18 defects, diagnosed using both techniques. One case was an isochromosome and the other was a partial duplication. Quantitative fluorescent PCR was an invaluable tool for the cytogenetics laboratory.

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En Costa Rica, el diagnóstico de anomalías cromosómicas fetales se realiza solo mediante el análisis citogenético convencional de cromosomas obtenidos de cultivos celulares. Además de que la espera por los resultados puede ser larga, con alguna frecuencia fracasa el cultivo, por contaminación o por mala calidad de la muestra, o las figuras mitóticas no se pueden analizar, por lo que es necesario disponer de una metodología sencilla y barata, para obtener un diagnóstico prenatal rápido y fiable de trisomía 21, 18 ó 13, en embarazos de alto riesgo genético sometidos a amniocentesis o cordocentesis. Métodos: Se diseñaron tres PCRs multiplex para amplificar cuatro distintas repeticiones cortas en tándem, de cada uno de los cromosomas 21, 18 y 13. Se colectaron 93 muestras (88 líquidos amnióticos y 5 sangres fetales), recibidas en el laboratorio entre 2006 y 2008, con solicitud de análisis cromosómico. Los resultados de la reacción en cadena de la polimerasa cuantitativa fluorescente, fueron comparados con el cariotipo obtenido de las mismas muestras para demostrar la fiabilidad del ensayo. Resultados: Para este grupo de datos, la exactitud del ensayo fue del 100 por ciento y se consiguió obtener resultados en 48 horas. Se logró realizar el análisis de repeticiones cortas en tándem en el 77 por ciento de las muestras en las que no se pudo obtener crecimiento celular. Conclusión: La reacción en cadena de la polimerasa cuantitativa fluorescente demostró ser una metodología sencilla, fiable y rápida, por lo que podría convertirse en una herramienta complementaria del análisis cromosómico convencional. La obtención de resultados rápidos en casos de diagnóstico prenatal podría disminuir el periodo de ansiedad parental por la espera de los resultados, así como permitir un mejor abordaje terapéutico de los fetos afectados.

In Costa Rica, the diagnosis of chromosomal fetal anomalies is realizedonly by conventional cytogenetic analysis of chromosomes obtained from cellular cultures. The waiting for the results can be long. Moreover with some frequency culture fails due tocontamination or bad quality of the sample or they cannot be analyzed. This makes it necessary to have a simple and cheap methodology to obtain an accurate and rapid fetal diagnosis of trisomy 21, 18 or 13, in pregnancies of high genetic risk submitted to amniocentesis or cordocentesis. Materials and methods: Three multiplex PCRs were designed to amplify four different short tandem repeats of each of the chromosomes 21, 18 and 13. There were collected 93 samples (88amniotic fluids and 5 fetal bloods), received in the laboratory between 2006 and 2008 with request ofor chromosomal analysis. The results of the quantitative fluorescent PCR werecompared with the obtained cariotype of the same samples to stablish the accuracy demonstrate the reliability of the assay. Results: Accuracy of the assay was 100% and it was possible to obtain results within 48 hours.STRs analysis could be made in 77% of the samples where the cellular culture could not be done. Conclusion: The quantitative fluorescent PCR demonstrated to be a simple, accurate and rapid methodology, from what it might turn into a complementary tool of the chromosomal conventional analysis. The securing of rapid results in cases of antenatal diagnosis might diminish the period of anxiety parental for the waiting of the results, as well as to allow a better therapeutic management of the affected fetuses.

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Objetivo: Identificar cromosomopatía fetal en embarazos de alto riesgo, así como brindar adecuada atención obstétrica, pediátrica y asesoramiento genético. Material y métodos: En 290 embarazadas se obtuvieron células fetales mediante amniocentesis, realizadas desde enero de 2000 hasta agosto de 2003 inclusive, en hospitales de la seguridad social y en la consulta privada. La indicación de las punciones fue por examen ultrasonográfico anormal en 44% de los casos y por edad materna avanzada en 39%. El 91% de los estudios se realizaron en el segundo trimestre del embarazo. Se utilizó el sistema cerrado de histocultivo y la cosecha por suspensión. El resultado final se obtuvo en 16 días (mediana). Durante el mismo periodo se estudiaron 18 embarazos mediante cordocentesis y cariotipo fetal. La indicación en todos los casos, excepto uno, fue examen ultrasonográfico anormal. Las cordocentesis se realizaron desde la semana 17 hasta la 35. Resultados: Los 230 cariotipos fetales obtenidos en muestras de líquido amniótico fueron anormales en 28 casos (12%). Se encontró concordancia entre el cariotipo y el fenotipo del feto o recién nacido, al igual que entre el diagnóstico ultrasonográfico fetal y la condición del neonato. El cariotipo en muestras de sangre fetal fue anormal en el 27% de los estudios. Conclusiones: La cromosomopatía fetal es la responsable de un buen número de alteraciones sonográficas durante el embarazo y de desenlaces obstétricos desfavorables. Conviene su detección precoz para tratar de minimizar el daño asociado a estos defectos citogenéticos.

Objective: The identification of fetal abnormal chromosomes to allow proper pediatric and obstetric management of the cases as well as genetic counseling. Material and methods: The results of 290 genetic amniocentesis from January 2000 to August 2003, are reported. There were two main reasons for referral: abnormal ultrasound assessment (44% of cases) and advanced maternal age (39%). Most procedures (91%) were performed during the second trimester of pregnancy. Fetal cells were closed cultured and suspension harvested. Turn around time was 16 days median. G banded (300-400 bands resolution) chromosomes from 20 cells provided by two independent cultures were karyotyped in each case. The results of 18 genetic percutaneous umbilical cord samplings from January 2002 to August 2003, are also reported. Almost all procedures were performed due to abnormal ultrasound findings from gestational week 17 to 35. Results: In 230 fetal karyotypes obtained from amniotic fluid, 27 (12%) were abnormal, due to 12 autosomal trisomies , three cases of monosomy X, three mosaics involving chromosome X, three triploid karyotypes, two balanced translocations of maternal origin, one structurally abnormal chromosome and three other defects of sexual chromosomes in males. Prenatal cytogenetic and sonographic findings correlated with the fetal or newborn phenotype in all cases available for follow-up. Fetal abnormal chromosomes obtained from fetal blood were: two cases of trisomy 13, one fetus with trisomy 18, and one case of trisomy 21. Conclusion: Chromosome defects are an important reason for ultrasonographic fetal abnormalities and adverse pregnancy outcomes. Normal results provided reassurance to the parents.