The Latin American Biological Dosimetry Network (LBDNet).

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included.

Interlaboratory comparison of dicentric chromosome assay using electronically transmitted images.

The bottleneck in data acquisition during biological dosimetry based on a dicentric assay is the need to score dicentrics in a large number of lymphocytes. One way to increase the capacity of a given laboratory is to use the ability of skilled operators from other laboratories. This can be done using image analysis systems and distributing images all around the world. Two exercises were conducted to test the efficiency of such an approach involving 10 laboratories. During the first exercise (E1), the participant laboratories analysed the same images derived from cells exposed to 0.5 and 3 Gy; 100 images were sent to all participants for both doses. Whatever the dose, only about half of the cells were complete with well-spread metaphases suitable for analysis. A coefficient of variation (CV) on the standard deviation of ∼15 % was obtained for both doses. The trueness was better for 3 Gy (0.6 %) than for 0.5 Gy (37.8 %). The number of estimated doses classified as satisfactory according to the z-score was 3 at 0.5 Gy and 8 at 3 Gy for 10 dose estimations. In the second exercise, an emergency situation was tested, each laboratory was required to score a different set of 50 images in 2 d extracted from 500 downloaded images derived from cells exposed to 0.5 Gy. Then the remaining 450 images had to be scored within a week. Using 50 different images, the CV on the estimated doses (79.2 %) was not as good as in E1, probably associated to a lower number of cells analysed (50 vs. 100) or from the fact that laboratories analysed a different set of images. The trueness for the dose was better after scoring 500 cells (22.5 %) than after 50 cells (26.8 %). For the 10 dose estimations, the number of doses classified as satisfactory according to the z-score was 9, for both 50 and 500 cells. Overall, the results obtained support the feasibility of networking using electronically transmitted images. However, before its implementation some issues should be elucidated, such as the number and resolution of the images to be sent, and the harmonisation of the scoring criteria. Additionally, a global website able to be used for the different regional networks, like Share Points, will be desirable to facilitate worldwide communication.

Biological dosimetry intercomparison exercise: an evaluation of triage and routine mode results by robust methods.

Well-defined protocols and quality management standards are indispensable for biological dosimetry laboratories. Participation in periodic proficiency testing by interlaboratory comparisons is also required. This harmonization is essential if a cooperative network is used to respond to a mass casualty event. Here we present an international intercomparison based on dicentric chromosome analysis for dose assessment performed in the framework of the IAEA Regional Latin American RLA/9/054 Project. The exercise involved 14 laboratories, 8 from Latin America and 6 from Europe. The performance of each laboratory and the reproducibility of the exercise were evaluated using robust methods described in ISO standards. The study was based on the analysis of slides from samples irradiated with 0.75 (DI) and 2.5 Gy (DII). Laboratories were required to score the frequency of dicentrics and convert them to estimated doses, using their own dose-effect curves, after the analysis of 50 or 100 cells (triage mode) and after conventional scoring of 500 cells or 100 dicentrics. In the conntional scoring, at both doses, all reported frequencies were considered as satisfactory, and two reported doses were considered as questionable. The analysis of the data dispersion among the dicentric frequencies and among doses indicated a better reproducibility for estimated doses (15.6% for DI and 8.8% for DII) than for frequencies (24.4% for DI and 11.4% for DII), expressed by the coefficient of variation. In the two triage modes, although robust analysis classified some reported frequencies or doses as unsatisfactory or questionable, all estimated doses were in agreement with the accepted error of ±0.5 Gy. However, at the DI dose and for 50 scored cells, 5 out of the 14 reported confidence intervals that included zero dose and could be interpreted as false negatives. This improved with 100 cells, where only one confidence interval included zero dose. At the DII dose, all estimations fell within ±0.5 Gy of the reference dose interval. The results obtained in this triage exercise indicated that it is better to report doses than frequencies. Overall, in both triage and conventional scoring modes, the laboratory performances were satisfactory for mutual cooperation purposes. These data reinforce the view that collaborative networking in the case of a mass casualty event can be successful.

Conocimientos, creencias y conductas en salud oral en adultos mayores de nivel socioeconómico bajo, zona norte de Santiago / Knowledge, believes and behavior in oral health in aging adults of low socioeconomic level at north Santiago

El Ministerio de Salud ha determinado crear una modalidad de atención integral específica para los adultos mayores, con un fuerte componente de educación para la salu. Para planificar programas educativos efectivos hay que conocer las creencias, conocimientos, valores y actitudes de los usuarios. Para determinarlas, se utilizaron 26 de los 60 ítemes de un cuestionario aplicado a una muestra de 228 adultos mayores, en 7 consultorios del área norte de la Región Metropolitana. Un 25,9 por ciento de la muestra eran desdentados totales y los dentados presentaban una mediana de 10 dientes. Se utilizó la prueba estadística de Ji cuadrado con p<0,05 para sexo, edad y nivel educacional. Se observó que, si bien los adultos mayores creen en la posibilidad de conservar al menos parte de la dentadura, la formación de caries es inevitable. La mayoría de los entrevistados desconoce la causa de la formación de caries y las conductas que conocen y practican para evitar esa patología son escasas. El autoexamen que muchos declaran realizar no detecta la mayoría de las caries que presentan. La falta de conocimientos y de percepción del problema de salud periodontal es notoria. El control periódico con el dentista es bajo, y la visita al dentista se posterga hasta experimentar un gran dolor. El origen de estos conocimientos proviene principalmente de la familia. Se concluye que la educación en salud oral para adultos mayores es una necesidad urgente y debe ir precedida por la capacitación de los profesionales que la impartirán tanto en los contenidos como en la metodología a utilizar

Salud oral y conductas asociadas en adultos mayores de bajos recursos / Oral health and associated behaviors in elder adults of low resources

El Ministerio de Salud ha detenninado crear una modalidad de atención integral específica para los adultos mayores, centrada en el nivel primario. Por ello hay que conocer sus necesidades de salud oral, en especial las protésicas y periodontales por ser las más frecuentes y difíciles de satisfacer. Se utilizó un cuestionario aplicado a una muestra de 228 adultos mayores, 25,9 por ciento hombres y 74,1 por ciento mujeres, entre 60 y 89 años, provenientes de 7 consultorios del Arca Norte de la Región Metropolitana. El 40,8 por ciento de la muestra tiene menos de 4 años de estudios. Se utilizó la prueba estadística de Ji cuadrado con p < 0,05, para las variables independientes sexo, edad y nivel educacional. El índice periodontal (INTPC) indica que el 16,6 por ciento requiere tratamiento periodontal complejo y el 54,3 por ciento necesita destartraje y pulido radicular. Sólo 43,0 por ciento ha visitado al dentista en los últimos 12 meses. El 50 por ciento tiene 7 o menos piezas dentarias en boca, el 25,9 por ciento es desdentado total. Un 30,3 por ciento carece de prótesis, de este sólo 8,7 por ciento desea usarla. Del 67,5 por ciento que posee prótesis, hay que rehacer o reparar 53,3 por ciento, sólo el 44,2 por ciento las mantiene en buen estado de higiene y 91,5 por ciento necesita instrucción en higiene oral. La preferencia por alimentos blandos es significativamente mayor en las personas sin prótesis y la necesitan. Se concluye que esta población es muy poco demandante de servicios dentales y es urgente implementar servicios de prótesis, periodoncia y autocuidado de salud oral en la atención primaria específicamente diseñados para adultos mayores, con criterios validados para la selección de pacientes

Dengue severity throughout seasonal changes in incidence in Puerto Rico, 1989-1992. The Puerto Rico Association of Epidemiologists.

To determine whether the proportion of severe dengue cases increased with the yearly seasonal increase in dengue incidence, we examined reports of disease symptoms in case surveillance data and laboratory testing results in Puerto Rico from January 1989 to July 1992. A computer algorithm was designed to identify severe cases, i.e., those that fulfilled three or all four of the World Health Organization criteria for dengue hemorrhagic fever (DHF). A monthly severity index (SI) was defined as the ratio of severe cases to laboratory-positive and indeterminate (all non-negative) cases for each month, while a more restrictive severity rate (SR) was defined as the ratio of severe laboratory-positive cases to the total number of laboratory-positive cases for each month. Monthly SI and SR were compared in two ways: within an epidemic cycle, and month-by-month. Linear regression analysis was performed over the monthly averages of the SI and SR. For a month-by-month examination of SI and SR, we examined the 43-month sequence by means of a linear model with autocorrelated disturbances. We found no statistically significant or cyclical change in the proportion of severe cases from month to month in this period. Our conclusions differ from the observations during the Cuban DHF epidemic of 1981, in which case severity was shown to increase markedly as the epidemic progressed; they agree with the conclusions of most previous studies in that dengue severity does not change significantly throughout a period of increased incidence.