Utility of Genetic Testing in Patients with Transthyretin Amyloid Cardiomyopathy: A Brief Review.

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly diagnosed condition. Although wild-type transthyretin amyloidosis (ATTRwt) is the most common ATTR-CM, hereditary transthyretin amyloidosis (ATTRv) may also occur. Currently, genetic testing for transthyretin pathogenic variants is recommended for patients with a confirmed clinical diagnosis of ATTR-CM. In fact, confirmation of this autosomal dominant pathogenic variant prompts genetic counselling and allows early identification of affected relatives. Additionally, in the presence of an ATTR-CM-associated polyneuropathy, specific drugs targeting transthyretin can be used. In this paper, we review the utility of genetic testing for the detection of pathogenic variants among patients harboring ATTR-CM and its impact on the natural history of the disease.

Update on controls for isolation and quantification methodology of extracellular vesicles derived from adipose tissue mesenchymal stem cells.

The research field on extracellular vesicles (EV) has rapidly expanded in recent years due to the therapeutic potential of EV. Adipose tissue human mesenchymal stem cells (ASC) may be a suitable source for therapeutic EV. A major limitation in the field is the lack of standardization of the challenging techniques to isolate and characterize EV. The aim of our study was to incorporate new controls for the detection and quantification of EV derived from ASC and to analyze the applicability and limitations of the available techniques. ASC were cultured in medium supplemented with 5% of vesicles-free fetal bovine serum. The EV were isolated from conditioned medium by differential centrifugation with size filtration (0.2 µm). As a control, non-conditioned culture medium was used (control medium). To detect EV, electron microscopy, conventional flow cytometry, and western blot were used. The quantification of the EV was by total protein quantification, ExoELISA immunoassay, and Nanosight. Cytokines and growth factors in the EV samples were measured by multiplex bead array kit. The EV were detected by electron microscope. Total protein measurement was not useful to quantify EV as the control medium showed similar protein contents as the EV samples. The ExoELISA kits had technical troubles and it was not possible to quantify the concentration of exosomes in the samples. The use of Nanosight enabled quantification and size determination of the EV. It is, however, not possible to distinguish protein aggregates from EV with this method. The technologies for quantification and characterization of the EV need to be improved. In addition, we detected protein contaminants in the EV samples, which make it difficult to determine the real effect of EV in experimental models. It will be crucial in the future to optimize design novel methods for purification and characterization of EV.

Modificaciones de los valores de gases y equilibrio ácido base en sangre arterial por acción del tiempo a temperatura ambiente / Modifications of the gas values and base acid balance in arterial blood by time action at environment temperature

Hemos observado que el traslado de las muestras de sangre para el análisis de gases y equilibrio ácido-base desde diferentes servicios del hospital hacia el laboratorio de gases, no se hace en el tiempo correspondiente ni en las condiciones adecuadas debido a una serie de factores, siendo uno de los más importantes el déficit de personal. Se trabajó con 50 pacientes adultos hospitalarios en el Servicio de Medicina del Hospital Clínico de la Universidad de Chile, a los que se les hubiese solicitado el examen y que no se les hubiera administrado oxígeno. A cada paciente de una punción se le extrajeron dos muestras de sangre arterial en jeringas de vidrio. Una muestra se trabajó en forma inmediata a su extracción y la otra muestra se deja a temperatura ambiente para ser analizada aproximadamente 30' después de la anterior. Después de los dos análisis podemos concluir que: el 100 por ciento de los exámenes experimentan modificaciones en alguno de sus parámetros. Valores normales en la primera muestra se hacen patológicos a los 30' y a la vez valores patológicos en la primera muestra se hacen normales a los 30 minutos. El 74 por ciento de las muestras que fueron analizadas 30 minutos después de extraídas experimentan modificaciones sobre el 10 por ciento en algunos parámetros y este porcentaje de variación para los pacientes es significativo. Por lo tanto las muestras de sangre para el análisis de gases y equilibrio ácido-base deben ser enviadas al laboratorio inmediatamente después de su extracción previamente introducida en un receptáculo con hielo. Los resultados de las muestras de gases, enviadas en este laboratorio corresponderán a las condiciones clínicas del paciente y los médicos podrán impartir el tratamiento adecuado