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Background and Objective: Dehydration and hyperhydration impact athletes' performance. Exploring the fluid balance concerning body composition might help estimate individual hydration requirements. This area of research, particularly regarding sodium losses, has been relatively understudied. We evaluated the sweat rate (SR), sweat sodium losses, and their relationship with body composition in professional soccer players in Cali, Colombia. Materials and Methods: Thirty-two male players, aged 24.3 (±5.2) years, from the Colombian main soccer league, underwent high-intensity training at 32 °C (with a relative humidity of 79%). The outcome variables included SR, calculated using weight loss and fluid intake; forearm sweat sodium concentration (FSCC), measured through the direct ion-selective electrode method; and estimated the predicted whole sweat sodium loss (PWSSL) in mmol. Predictor variables (body mass, fat, and muscle masses) were estimated using the Deborah Kerr anthropometry method. The association between predictors and outcomes was assessed using linear regression. Results: The mean FSCC, PWSSL, and SR were 26.7 ± 11.3 mmol/L, 43 ± 15.9 mmol/L, and 1.7 ± 0.5 L/h, respectively. Body mass positively predicted FSCC in unadjusted and age/fat-mass-adjusted models [Beta 1.28, 95% confidence interval (CI) 0.39-2.18, p = 0.006], and continued related to FSCC after adjustment for muscle mass with marginal significance [Beta 0.85, 95% CI -0.02 to 1.73, p = 0.056]. Muscle mass was associated with the PWSSL in unadjusted and age/fat-mass-adjusted models [Beta 2.42, 95% CI 0.58-4.26, p = 0.012] and sustained an association with marginal statistical significance after adjustment for body mass [Beta 1.86, 95% CI -0.35 to 4.09, p = 0.097]. Conclusions: Under hot tropical weather conditions, FSCC was relatively low among the players. Body mass was better associated with the FSSC, and muscle mass better related to the PWSSL. Body and muscle masses could be regarded as potential factors to be explored in the estimation of individual sodium needs. However, further studies are required to validate and contrast our findings.

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The new coronavirus disease (COVID-19), pneumonia, tuberculosis, and breast cancer have one thing in common: these diseases can be diagnosed using radiological studies such as X-rays images. With radiological studies and technology, computer-aided diagnosis (CAD) results in a very useful technique to analyze and detect abnormalities using the images generated by X-ray machines. Some deep-learning techniques such as a convolutional neural network (CNN) can help physicians to obtain an effective pre-diagnosis. However, popular CNNs are enormous models and need a huge amount of data to obtain good results. In this paper, we introduce NanoChest-net, which is a small but effective CNN model that can be used to classify among different diseases using images from radiological studies. NanoChest-net proves to be effective in classifying among different diseases such as tuberculosis, pneumonia, and COVID-19. In two of the five datasets used in the experiments, NanoChest-net obtained the best results, while on the remaining datasets our model proved to be as good as baseline models from the state of the art such as the ResNet50, Xception, and DenseNet121. In addition, NanoChest-net is useful to classify radiological studies on the same level as state-of-the-art algorithms with the advantage that it does not require a large number of operations.

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It is commonly assumed that methane (CH4) released by lakes into the atmosphere is mainly produced in anoxic sediment and transported by diffusion or ebullition through the water column to the surface of the lake. In contrast to that prevailing idea, it has been gradually established that the epilimnetic CH4 does not originate exclusively from sediments but is also locally produced or laterally transported from the littoral zone. Therefore, CH4 cycling in the epilimnion and the hypolimnion might not be as closely linked as previously thought. We utilized a high-resolution method used to determine dissolved CH4 concentration to analyze a Siberian lake in which epilimnetic and hypolimnetic CH4 cycles were fully segregated by a section of the water column where CH4 was not detected. This layer, with no detected CH4, was well below the oxycline and the photic zone and thus assumed to be anaerobic. However, on the basis of a diffusion-reaction model, molecular biology, and stable isotope analyses, we determined that this layer takes up all the CH4 produced in the sediments and the deepest section of the hypolimnion. We concluded that there was no CH4 exchange between the hypolimnion (dominated by methanotrophy and methanogenesis) and the epilimnion (dominated by methane lateral transport and/or oxic production), resulting in a vertically segregated lake internal CH4 cycle.

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BACKGROUND: The determination of surgeons' psychomotor skills in minimally invasive surgery techniques is one of the major concerns of the programs of surgical training in several hospitals. Therefore, it is important to assess and classify objectively the level of experience of surgeons and residents during their training process. The aim of this study was to investigate three classification methods for establishing automatically the level of surgical competence of the surgeons based on their psychomotor laparoscopic skills. METHODS: A total of 43 participants, divided into an experienced surgeons group with ten experts (> 100 laparoscopic procedures performed) and non-experienced surgeons group with 24 residents and nine medical students (< 10 laparoscopic procedures performed), performed three tasks in the EndoViS training system. Motion data of the instruments were captured with a video-tracking system built into the EndoViS simulator and analyzed using 13 motion analysis parameters (MAPs). Radial basis function networks (RBFNets), K-star (K*), and random forest (RF) were used for classifying surgeons based on the MAPs' scores of all participants. The performance of the three classifiers was examined using hold-out and leave-one-out validation techniques. RESULTS: For all three tasks, the K-star method was superior in terms of accuracy and AUC in both validation techniques. The mean accuracy of the classifiers was 93.33% for K-star, 87.58% for RBFNets, and 84.85% for RF in hold-out validation, and 91.47% for K-star, 89.92% for RBFNets, and 83.72% for RF in leave-one-out cross-validation. CONCLUSIONS: The three proposed methods demonstrated high performance in the classification of laparoscopic surgeons, according to their level of psychomotor skills. Together with motion analysis and three laparoscopic tasks of the Fundamental Laparoscopic Surgery Program, these classifiers provide a means for objectively classifying surgical competence of the surgeons for existing laparoscopic box trainers.

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The Cuatro Cienegas Basin (CCB) in the Chihuahuan desert is characterized by the presence of over 500 ponds located in an endorheic basin. These ponds are subsaline ecosystems characterized by a low productivity and a particularly high sulfate concentration, comparable to marine environments. This study focused on assessing the main physicochemical parameters in these ponds along with the characterization of the CH4 dynamics through the determination of fluxes, dissolved CH4 concentrations, and net methanotrophic and methanogenic activity. Despite a sulfate concentration ranging from 1.06 to 4.73 g L-1, the studied ponds showed moderate but clear CH4 production and emission, which suggests that methanogenesis is not completely outcompeted by sulfate reduction. CH4 fluxes ranged from 0.12 to 0.98 mg m-2 d-1, which falls within the higher range of marine emissions and within the lower range reported for coastal saline lagoons and saline ponds. During summer, significant CH4 production in the oxic water column was observed. In addition to CH4, CO2 fluxes were determined at levels from 0.2 to 53 g m-2 d-1, which is within the range recorded for saline lakes in other parts of the world. Our results provide additional evidence that subsaline/saline aquatic ecosystems play an important role in the emission of greenhouse gases to the atmosphere.

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An open dynamic chamber for the continuous monitoring of diffusive and ebullitive fluxes of methane (CH4) in aquatic ecosystems was designed and developed. This method is based on a standard floating chamber in which a well-defined carrier gas flows. The concentration of CH4 is measured continuously at the outlet of the chamber, and the flux is determined from a mass balance equation. The method was carefully tested in a laboratory and was subsequently applied to two lakes, in Mexico, with contrasting trophic states. We show here that the method allows for the continuous quantification of CH4 diffusive flux higher than 25 × 10-6 g m-2 h-1, the determination of ebullitive flux, and the individual characterization of bubbles larger than 1.50-1.72 mm in diameter. The method was also applied to determine carbon dioxide emissions (CO2). In that case, the method was less sensitive but allowed for the characterization of diffusive fluxes higher than 10 mg CO2 m-2 h-1 and of bubbles larger than 5.3-8.4 mm in diameter. This high-throughput method can be adapted to any gas detector at low cost, making it a convenient tool to better constrain greenhouse gas emission from freshwater ecosystems.

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The rapid proliferation of connectivity, availability of ubiquitous computing, miniaturization of sensors and communication technology, have changed healthcare in all its areas, creating the well-known healthcare paradigm of e-Health. In this paper, an embedded system capable of monitoring, learning and classifying biometric signals is presented. The machine learning model is based on associative memories to predict the presence or absence of coronary artery disease in patients. Classification accuracy, sensitivity and specificity results show that the performance of our proposal exceeds the performance achieved by each of the fifty widely known algorithms against which it was compared.

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The sub-Antarctic Magellanic ecoregion is a part of the world where ecosystems have been understudied and where the CH4 cycling and emissions in lakes has not ever been reported. To fill that knowledge gap, a lake and a reservoir located at 53°S were selected and studied during three campaigns equally distributed over one year. Among the parameters measured were CH4 and CO2 emissions, as well their dissolved concentrations in the water column, which were determined with high spatial resolution. No ebullition was observed and the CH4 flux ranged from 0.0094 to 4.47mmolm-2d-1 while the CO2 flux ranged from -22.95 to 35.68mmolm-2d-1. Dissolved CH4 concentrations varied over more than four orders of magnitude (0.025-128.75µmolL-1), and the dissolved carbon dioxide ranged from below the detection limit of our method (i.e., 0.15µmolL-1) to 379.09µmolL-1. The high spatial resolution of the methods used enabled the construction of bathymetric maps, surface contour maps of CH4 and CO2 fluxes, and transect contour maps of dissolved oxygen, temperature, and dissolved greenhouse gases. Overall, both lakes were net greenhouse gas producers and were not significantly different from temperate lakes located at a similar northern latitudes (53°N), except that ebullition was never observed in the studied sub-Antarctic lakes.

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ABSTRACT Introduction: Hemoglobinopathies are among the most common genetic disorders of hemoglobin worldwide and a public health problem. In Colombia, even though geographical areas with high incidence of this disorder have been reported, the absence of a national screening program does not permit us to determine its prevalence. Objective: Establish the prevalence of hemoglobin variants in a population covered by the neonatal screening program of Clínica Colsanitas S.A., between June 2000 and December 2014, including eight capital cities in Colombia. Methods: A retrospective cross-sectional study was conducted. We collected data from reports of the neonatal hemoglobinopathy-screening program for full-term newborn babies between 5 and 15 days old. Qualitative hemoglobin analysis was performed using gel electrophoresis of blood samples taken from the babies' heels. Results: The overall prevalence of abnormal Hb was 1.3%. Within the groups of newborns affected with any hemoglobinopathy (n = 400), the most frequent abnormal structural hemoglobins found were HbS (43%), HbC (9%), fast Hb (8%). For quantitative hemoglobins, HbA2 was 3.7% and HbA kept slightly elevated in 14.7% of cases. Frequency of homozygosis for HbS was 0.01%. Barranquilla, Cartagena and Cali were the cities with the greatest frequency of hemoglobinopathies. No correlation between sex and abnormal hemoglobin was found. Discussion and conclusion: Taking in consideration data from the World Health Organization (WHO) on hemoglobinopathies, our prevalence of > 1% is considered high. Therefore, a more extended coverage and the need for a national screening program are priorities.

RESUMO Introdução: As hemoglobinopatias são doenças genéticas comuns em todo o mundo e representam um problema de saúde pública. Na Colômbia, embora existam áreas geográficas com maior risco de apresentá-las, não há programas de triagem nem estudos para estabelecer sua prevalência na população. Objetivo: Estabelecer a prevalência de variantes de hemoglobina (Hb) na população pertencente ao programa de triagem neonatal da Clínica Colsanitas S.A. entre junho de 2000 e dezembro de 2014, em oito cidades do país. Métodos: Estudo transversal retrospectivo. Os registros do programa de triagem neonatal das hemoglobinopatias foram revistos para a informação dos resultados de eletroforese de hemoglobina em pH alcalino, praticada no sangue dos recém-nascidos com idades compreendidas entre 5-15 dias. Resultados: A prevalência geral de Hb anormal foi de 1,3%. Dentro dos grupos de recém-nascidos afetados com qualquer hemoglobinopatia (n = 400), as hemoglobinas anormais estruturais mais frequentes foram hemoglobina S (HbS) (43%), hemoglobina C (HbC) (9%) e Hb rápida (8%). Para as Hb quantitativas, o aumento da hemoglobina A2 (HbA2) foi de 3,7%, e a hemoglobina A (HbA) aumentada permaneceu ligeiramente elevada em 14,7% casos. A frequência de homozigotos para HbS foi de 0,01%. Barranquilla, Cartagena e Cali foram as cidades com maior frequência de hemoglobinopatias. Não houve associação entre sexo e presença de algum tipo de Hb. Discussão e conclusão: A prevalência global de hemoglobinopatias em nosso estudo foi alta (> 1%) de acordo com os critérios da Organização Mundial de Saúde (OMS). Portanto, há a necessidade de implementação de programas de triagem neonatal com maior cobertura nacional para as hemoglobinopatias.

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ABSTRACT Introduction: The clinical laboratory is part of the group of actors in health systems that are under increasing pressure by users and administrators to increase their productivity in order to respond efficiently to the increased volume of patients, optimizing costs and professional time. This pressure forced laboratories to perform a full review of their procedures and develop technical, logistical and computational tools to enable excellent response times. Objective: This study aimed to evaluate the implementation of the automated blood cell counter autoverification process and its impact on the safety of patients. Methods: Verification rules were designed in the connectivity software, based on manual validation criteria for laboratory professionals, according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI) Guideline Auto10-A and the International Consensus Group for Hematology Review (ISLH). The autoverification percentage was established, and non-conforming product (NCP) percentages were estimated before and after the procedure. Pilot tests were also performed in different days so as to adjust the process. Results: 53.4% of automated blood cell counters autoverification were achieved, and, subsequently in the audit of 18 months, 60% was reached due to verification adjustments in the delta programmed filter. The NCPs rose from 0.065% to 0.0036% from the beginning to the end of the process. Conclusion: The autoverification process enabled to reduce the variability associated with human intervention, therefore the professional is able to focus on the pathological report analysis, reducing the risk of errors and advocating greater importance on patient safety.

RESUMO Introdução: O laboratório clínico é parte do grupo de atores nos sistemas de saúde, que são cada vez mais pressionados por usuários e administradores para aumentar sua produtividade a fim de responder de forma eficiente ao aumento do volume de pacientes, otimizando custos e tempo dos funcionários. Essa pressão forçou laboratórios para efetuar uma revisão completa de seus procedimentos, bem como desenvolver instrumentos técnicos, logísticos e computacionais para permitir excelentes tempos de resposta. Objetivo: Neste estudo, a implementação do processo automatizado de autoverificação do hemograma e seu impacto sobre a segurança do paciente são avaliados. Métodos: Regras de verificação foram construídas no software de conectividade com base em critérios de validação manual dos profissionais de laboratório, de acordo com as orientações do Clinical and Laboratory Standards Institute (CLSI) de Guideline Auto10-A e do International Consensus Group for Hematology Review (ISLH). A percentagem de autoensaio foi estabelecida e as de produtos não conformes (PNC), estimadas antes e depois do procedimento. Testes piloto foram realizados em dias diferentes para ajustar o processo. Resultados: Cinquenta e três por cento da autoverificação dos hemogramas automatizados foram alcançados e, posteriormente, na auditoria dos 18 meses, foram obtidos 60% devido a ajustes na verificação do filtro delta programado. Os PNCs aumentaram de 0,065% a 0,0036% desde o início até ao final do processo. Conclusão: O processo do autoverificação ajudou a reduzir a variabilidade associada à intervenção humana, portanto o profissional pode concentrar-se na análise de relatórios patológicos, reduzindo o risco de erros e dando maior importância para a segurança do paciente.

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A novel low-cost method for the combined, real-time, and in situ determination of dissolved methane and carbon dioxide concentrations in freshwater ecosystems was designed and developed. This method is based on the continuous sampling of water from a freshwater ecosystem to a gas/liquid exchange membrane. Dissolved gas is transferred through the membrane to a continuous flow of high purity nitrogen, which is then measured by an off-axis integrated cavity output spectrometer (OA-ICOS). This method, called M-ICOS, was carefully tested in a laboratory and was subsequently applied to four lakes in Mexico and Alaska with contrasting climates, ecologies, and morphologies. The M-ICOS method allowed for the determination of dissolved methane and carbon dioxide concentrations with a frequency of 1 Hz and with a method detection limit of 2.76 × 10(-10) mol L(-1) for methane and 1.5 × 10(-7) mol L(-1) for carbon dioxide. These detection limits are below saturated concentrations with respect to the atmosphere and significantly lower than the minimum concentrations previously reported in lakes. The method is easily operable by a single person from a small boat, and the small size of the suction probe allows the determination of dissolved gases with a minimized impact on shallow freshwater ecosystems.

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Classification is one of the key issues in medical diagnosis. In this paper, a novel approach to perform pattern classification tasks is presented. This model is called Associative Memory based Classifier (AMBC). Throughout the experimental phase, the proposed algorithm is applied to help diagnose diseases; particularly, it is applied in the diagnosis of seven different problems in the medical field. The performance of the proposed model is validated by comparing classification accuracy of AMBC against the performance achieved by other twenty well known algorithms. Experimental results have shown that AMBC achieved the best performance in three of the seven pattern classification problems in the medical field. Similarly, it should be noted that our proposal achieved the best classification accuracy averaged over all datasets.

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Introduction: The high polymorphism of the HLA system allows its typification to be used as valuable tool in establishing association to various illnesses, immune and genetic profiles; it also provides a guide to identifying compatibility among donors and receptors of organs transplants. Objective: To establish HLA-A, HLA-B, and HLA.DRB1 allele, genotype and haplotype frequencies among patients treated at Clinica Colsanitas SA. Methods: 561 patients coming from different regions in Colombia, who were attended in 8 centers of the clinical laboratory of the Clinica Colsanitas in different cities of the country from January 2004 to August 2008, were included in this study. All were HLA-A,-B, and -DRB1 typified via SSP PCR. Allele, genotype and haplotype frequencies were estimated with STATA Software Version 9.0 and the GENEPOP genetic analysis package. Results: 19, 28, and 15 different alleles were identified for loci HLA-A,-B and -DRB1, respectively. Alleles found most frequently were A*24 (26.2%), A*02 (26%), B*35(22.7%), and DRB1*04 (24%). The most frequent genotypes were A*02,24 (14.2%), B*07,35 (5.5%), DRB1*01,04, and DRB1*04,04 (6.9%); while most the frequent haplotypes were HLA A*24, B*35 (9.2%), A*24, DRB1*04 (8.1%); B*35, DRB1*04 (7.8%), A*2 DRB1*04 (7.4%). Conclusion: The results obtained provide a useful reference framework for the population studied, allowing compatibility probability calculations to be performed for organ transplants.

Introducción: El alto polimorfismo del sistema HLA, hace que su tipificación sea una herramienta de gran valor al establecer asociación con diferentes enfermedades, patrones inmunológicos, antropogenéticos, así como para establecer probabilidades de encontrar donantes compatibles con receptores de diferentes tipos de trasplante de órganos. Objetivo: Establecer las frecuencias alélicas, genotípicas y haplotípicas en pacientes atendidos en la Clínica Colsanitas SA. Metodología: Se incluyeron un total de 561 pacientes atendidos en el Laboratorio Clínico de La Clínica Colsanitas SA, en 8 sedes en diferentes ciudades del Colombia, durante el período comprendido entre enero de 2004 a agosto de 2008. Se realizó tipificación de HLA -A,-B,-DRB1 por PCR SSP. Las frecuencias alélicas, genotípicas y haplotípicas fueron estimadas mediante el paquete estadístico Stata y el paquete de análisis genético Genepop. Resultados: Fue posible la identificación de 19, 28 y 15 alelos de los loci HLA A-B-DRB1 respectivamente, de los cuales los más frecuentes fueron A*24 (26.2%), A*02 (26%), B*35 (22.7%), DRB1*04 (24%). Los genotipos más frecuentes encontrados fueron A*02,24 (14.2%), B*07,35 (5.5%), DRB1*01,04 y DRB1*04,04 (6.9%). Los haplotipos más frecuentes fueron: HLA A*24, B*35 (9.2%), A*24, DRB1*04 (8.1%); B* 35, DRB1*04 (7.8%), A*2 DRB1*04 (7.4%). Conclusión: Los resultados obtenidos permiten tener referencia para aplicaciones en la población estudiada, así como para establecer probabilidades de compatibilidad en la creciente área de trasplante de órganos.

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OBJECTIVE: This study was aimed at determining anti-human T-lymphotropic virus I/II (HTLV I/II) seroprevalence amongst blood-donors at the Clínica Reina Sofía in Bogotá, Colombia between 1999 and 2004. METHODS: All people donating blood at the Clínica Reina Sofía were selected for anti-HTLV I/II testing; a survey was carried out which focused on risk factors. All blood donations were screened by using enzyme immunolinked assay (ELISA); repeatedly reactive serum samples were confirmed as being HTLV I or HTLV II by using Western blot (WB). RESULTS: 8,913 blood donors, 5,883 (66 %) males and 3,030 (34 %) females having a mean age of 37 were included in the study; 26 (0,3 %) were repeatedly reactive in ELISA tests, 6 (0,07 %) of whom were confirmed by using Western blot (WB). Our findings revealed 0,07 % HTLV seroprevalence amongst blood-donors, in line with other European and South-American countries. CONCLUSION: Although our findings suggest low HTLV I/II seroprevalence, blood-donors should be routinely screened to minimise transmission due to occult HTLV I/II infection in Colombia.

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Objetivo: Determinar la prevalencia de anticuerpos para HTLV I/II, en los donantes de sangre del Banco de Sangre de la Clínica Reina Sofía, ubicada en Bogotá, Colombia. Métodos: Fueron incluidas las muestras de todos los donantes de sangre en el período comprendido entre Abril de 1999 y Agosto de 2004. A estas muestras se les realizó un ELISA para identificación de los virus HTLV I/II; a los donantes con muestras reactivas se les tomó una nueva muestra, la cual se confirmó mediante Western blot (WB). Se analizaron las encuestas de todos los donantes con pruebas reactivas para HTLV I/II en el periodo descrito y se diligenció un formulario con las variables. Resultados: La población total de donantes de sangre estudiados en los cinco años fue de 8 913 donantes, 5 883 (66 por ciento) hombres y 3 030 (34 por ciento) mujeres, con un promedio de 37 años; de los cuales 26 (0,3 por ciento) tuvieron ELISA doblemente reactivo para HTLV I/II y, de estos, solo seis pacientes fueron confirmados mediante WB, los cuales representan una prevalencia de 0,07 por ciento Conclusión: Aunque nuestros hallazgos sugieren una baja seroprevalencia para HTLV I/II, nos permiten resaltar la importancia de implantar la prueba de detección de anticuerpos contra estos virus en todos los Bancos de Sangre del país junto con las demás pruebas que ya son indispensables según la legislación colombiana para poder suministrar sangre y hemocomponentes de calidad.

Objective: This study was aimed at determining anti-human T-lymphotropic virus I/II (HTLV I/II) seroprevalence amongst blood-donors at the Clínica Reina Sofía in Bogotá, Colombia between 1999 and 2004. Methods: All people donating blood at the Clínica Reina Sofía were selected for anti-HTLV I/II testing; a survey was carried out which focused on risk factors. All blood donations were screened by using enzyme immunolinked assay (ELISA); repeatedly reactive serum samples were confirmed as being HTLV I or HTLV II by using Western blot (WB). Results: 8 913 blood donors, 5 883 (66 percent) males and 3,030 (34 percent) females having a mean age of 37 were included in the study; 26 (0,3 percent) were repeatedly reactive in ELISA tests, 6 (0,07 percent) of whom were confirmed by using Western blot (WB). Our findings revealed 0,07 percent HTLV seroprevalence amongst blood-donors, in line with other European and South-American countries. Conclusion: Although our findings suggest low HTLV I/II seroprevalence, blood-donors should be routinely screened to minimise transmission due to occult HTLV I/II infection in Colombia.

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El presente trabajo se realizó con el objeto de corroborar y relacionar los aspectos estructurales de los molares primarios observados con MO y MEB y aplicar las técnicas de histoquímica microanalítica para determinar los patrones cuantitativos de mineralización del esmalte y dentina. Se utilizó un total de 30 molares (1º y 2º) clínicamente sanos, exfoliados. El estudio para microscopía óptica (MO) fue mediante la técnica por desgaste y cortes procesados y metalizados para la electrónica de barrido (MEB). En el esmalte se identificó la zona aprismática periférica, la líne

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El presente trabajo se realizó con el objeto de corroborar y relacionar los aspectos estructurales de los molares primarios observados con MO y MEB y aplicar las técnicas de histoquímica microanalítica para determinar los patrones cuantitativos de mineralización del esmalte y dentina. Se utilizó un total de 30 molares (1º y 2º) clínicamente sanos, exfoliados. El estudio para microscopía óptica (MO) fue mediante la técnica por desgaste y cortes procesados y metalizados para la electrónica de barrido (MEB). En el esmalte se identificó la zona aprismática periférica, la línea neonatal, abundantes husos, conductillos dentinarios remanentes y microdefectos (laminillas o cracks de morfología y longitud variables). La dentina se caracterizó por la amplitud de los túbulos y escasa o nula dentina intertubular a nivel circumpulpar. El microanálisis con energía dispersiva de rayos X puso de relieve que el índice calcio/fósforo, tanto en esmalte como en dentina, alcanza el valor de 1.7, lo que sugiere que en la configuración de los cristales de apatita existen aniones carbonato. Los hallazgos de frecuentes microdefectos y la presencia de numerosas estructuras sin esmalte (husos y conductillos penetrantes) en la conexión amelodentinaria, especialmente en la porción coronaria oclusal nos advierte de los cuidados o precauciones a tomar en el momento de usar ácidos grabadores. Asimismo, la existencia de patrones de mineralización similares entre elementos primarios y permanentes, permite inferir que la terapéutica odontológica basada en la naturaleza de lamineralización podría aplicarse con idénticas pautas, pero respetando las variaciones estructurales respectivas (AU)

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El presente trabajo se realizó con el objeto de corroborar y relacionar los aspectos estructurales de los molares primarios observados con MO y MEB y aplicar las técnicas de histoquímica microanalítica para determinar los patrones cuantitativos de mineralización del esmalte y dentina. Se utilizó un total de 30 molares (1º y 2º) clínicamente sanos, exfoliados. El estudio para microscopía óptica (MO) fue mediante la técnica por desgaste y cortes procesados y metalizados para la electrónica de barrido (MEB). En el esmalte se identificó la zona aprismática periférica, la línea neonatal, abundantes husos, conductillos dentinarios remanentes y microdefectos (laminillas o cracks de morfología y longitud variables). La dentina se caracterizó por la amplitud de los túbulos y escasa o nula dentina intertubular a nivel circumpulpar. El microanálisis con energía dispersiva de rayos X puso de relieve que el índice calcio/fósforo, tanto en esmalte como en dentina, alcanza el valor de 1.7, lo que sugiere que en la configuración de los cristales de apatita existen aniones carbonato. Los hallazgos de frecuentes microdefectos y la presencia de numerosas estructuras sin esmalte (husos y conductillos penetrantes) en la conexión amelodentinaria, especialmente en la porción coronaria oclusal nos advierte de los cuidados o precauciones a tomar en el momento de usar ácidos grabadores. Asimismo, la existencia de patrones de mineralización similares entre elementos primarios y permanentes, permite inferir que la terapéutica odontológica basada en la naturaleza de lamineralización podría aplicarse con idénticas pautas, pero respetando las variaciones estructurales respectivas

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RESUMO

La mayoría de las investigaciones histológicas efectuadas en elementos deciduos se refieren casi exclusivamente a los aspectos estructurales de algunos de sus tejidos en relación a la exfoliación o a la patología general o dentaria. Por ello, nuestro propósito fue realizar el estudio integral de los tejidos duros en los molares primarios funcionales, como base para futuras investigaciones de aplicación clínica. Se analizaron histológicamente un total de 30 molares clínicamente normales (26) y 4 molares primarios que ofrecían la denominada "mancha blanca". Se utilizó la técnica de desgaste para microscopía óptica (MO) y cortes a fractura para la electrónica de barrido (MEB). Las observaciones fueron las siguientes: a) en el esmalte, se identifica fácilmente la zona aprismática periférica, la línea neonatal y microdefectos. En el depósito posnatal se distinguen escasas estrías de Retzius, abundantes husos adamantinos y conductillos dentinarios penetrantes a nivel de la C.A.D. b) Es notable el cambio de dirección de los túbulos próximos al piso de la cavidad pulpar y la ausencia de dentina peritubular a este nivel. c) En el + 30 por ciento de los moalres estudiados se evidenciaron fisuras o zonas hipomineralizadas a nivel interradicular. Son poco frecuentes o nulos los espacios de Czermak. d) Predomina el cemento acelular. e) Los molares con lesión blanca ofrecen el típico cuadro histológico de la caries dental. Estos hallazgos aportan otros datos de interés sobre la estructura biológica de los tejidos dentarios primarios, importantes para su proyección clínica (AU)

Assuntos