Genotipificación del gen RHD en ADN fetal libre en plasma de embarazadas RhD negativo / Genotyping of the RHD gene in free fetal DNA in plasma of RhD negative pregnant women

Objetivo: Determinar el grupo RhD fetal a través del estudio del gen RHD en ADN fetal que se encuentra libre en plasma de embarazadas RhD negativo. Método: Se analizó la presencia de los genes RHD, SRY y BGLO en ADNfl obtenido de plasma de 51 embarazadas RhD negativo no sensibilizadas, utilizando una qPCR. Los resultados del estudio genético del gen RHD se compararon con el estudio del grupo sanguíneo RhD realizado por método serológico en muestras de sangre de cordón, y los resultados del estudio del gen SRY fueron cotejados con el sexo fetal determinado por ecografía. Se calcularon la sensibilidad, la especificidad, los valores predictivos y la capacidad discriminativa del método estandarizado. Resultados: El gen RHD estaba presente en el 72,5% de las muestras y el gen SRY en el 55,5%, coincidiendo en un 100% con los resultados del grupo RhD detectado en sangre de cordón y con el sexo fetal confirmado por ecografía, respectivamente. Conclusiones: Fue posible deducir el grupo sanguíneo RhD del feto mediante el estudio del ADN fetal que se encuentra libre en el plasma de embarazadas con un método molecular no invasivo desarrollado y validado para este fin. Este test no invasivo puede ser utilizado para tomar la decisión de administrar inmunoglobulina anti-D solo a embarazadas RhD negativo que portan un feto RhD positivo.

Objective: To determine the fetal RhD group through the study of the RHD gene in fetal DNA found free in plasma of RhD negative pregnant women. Method: The presence of the RHD, SRY and BGLO genes in fetal DNA obtained from plasma of 51 non-sensitized RhD negative pregnant women was analyzed using qPCR. The results of the genetic study of the RHD gene were compared with the RhD blood group study performed by serological method in cord blood samples, and the results of the SRY gene study were compared with the fetal sex determined by ultrasound. Sensitivity, specificity, predictive values and discriminative capacity of the standardized method were calculated. Results: The RHD gene was present in 72.5% of the samples and the SRY gene in 55.5%, coinciding 100% with the results of the RhD group detected in cord blood, and with the fetal sex confirmed by ultrasound, respectively. Conclusions: It was possible to deduce the RhD blood group of the fetus through the study of fetal DNA found free in the plasma of pregnant women with a non-invasive molecular method developed and validated for this purpose. This non-invasive test can be used to make the decision to administer anti-D immunoglobulin only to RhD-negative pregnant women carrying an RhD-positive fetus.

Nutritional phases of Prader-Willi syndrome. / Fases nutricionales en Síndrome de Prader-Willi.

INTRODUCTION: Prader-Willi Syndrome (PWS) is the most common cause of genetic obesity. Hyperphagia and obe sity are the most associated concepts with this condition. However, undernutrition secondary to severe hypotonia and feeding difficulties is the predominant initial feature. OBJECTIVE: to reprodu ce and communicate the nutritional phases on a series of Chilean cases with PWS. PATIENTS AND METHOD: Cross-sectional study in which clinical records of PWS individuals under nutritional con trol at the Clínica Santa María in Santiago, Chile between 2017 and 2018 were analyzed. The anthro pometric references of the World Health Organization were used to carry out the nutritional as sessment. The classification into nutritional phases was according to the Miller criteria. RESULTS: 24 patients from infants to adults were included. All children aged under 9 months were in phase I and had malnutrition or were eutrophic; those between 9 and 25 months were classified in phase 2a; pa tients between 2.1 and 4.5 years were distributed between phases 1 and 2 and 66% were eutrophic; those between 4.5 to 8 years, 80% were in phase 2a and 2b and obesity begins to appear, and patients over 8 years of age, 75% were in phase 3 and all are overweight or obese. There was an association bet ween nutritional phase and age but not between it and nutritional status. CONCLUSIONS: In our series, the nutritional phases described according to age were reproduced according to those internationally described. There was no association between nutritional status and age.

Assessment of the Usefulness of the Quantitative Methods for the Response Evaluation of Solid Tumors: Analysis Using Four Cancer Types.

BACKGROUND: The evidence provided by medical imaging techniques for the staging and follow-up is relevant in oncology. OBJECTIVES: The aims were (i) to compare the monitoring methods, (ii) to analyze the response variability between different tumors, and (iii) to decipher a general response curve that is independent of tumor type and drug treatment. METHODS: We analyzed the response variability in four cancer types, looking for a general response curve independent of the tumor type and drug treatment. We compared the response of different types of lesions within each cancer type via an intra-class correlation coefficient, determining the minimum number of lesions suitable for monitoring. RESULTS: The tested metrics allowed an objective evaluation of the response of solid tumors. The response was homogeneous between different cancer types. The intra-class correlation was high, allowing the monitoring of the response with a low number of lesions (2-4). The currently used metrics misrepresent the changes in the lesion volumes. Indeed, we observed non-linear overestimations of the RECIST and WHO values, which were more pronounced for the intermediate values. Additionally, the inclusion of lymphadenopathy among the target lesions produced a distortion in the evaluation of the response. CONCLUSION: The quantitative counts allowed an objective evaluation of the response of the solid tumors to therapy, showing that the response was homogeneous but variable between different types of tumors. Although the currently used metrics lead to misrepresentations of the changes in the lesion volume, they allowed setting a response pattern for tracking these lesions.