Development and validation of a method for simultaneous determination of pseudouridine and creatinine in human urine. Evaluation’s Index Pseudouridona/Creatinine in smokers and no-smokers

Introduction: The excretion of pseudouridine is increased in inflammatory processes related to a muscle mass loss found in patients with pulmonary involvement. Material and Methods: A rapid and sensitive method for cuantification and simultaneous determination of pseudouridine, a breakdown product of tRNA, and creatinine in human urine via HPLC was developed and validated. The mobile phase was 0.01 mol phosphate buffer (pH 6.1) containing 3 mmol octanesulphonic acid as ion pairing agent. Sample preparation is based on dilution and filtration. A LiCHros-pher® 100 RP-18 (5 μm) LiCHroCART® 250-4 (Merck) column with precolumn LiCHrospher® 100 RP-18 (5 μm) LiCHroCART® 50-4 (Merck) were used, flow rate of 1ml/min. Detection wavelength was set at 250 nm. Results: The analysis time was 17 min per sample. The calibration range of pseudouridine (Psu) and creatinine (Crea) were 0.23-22.5 and 11.45-1100 nmol/ml. The linearity of the method was r2 = 0.997 and 0.998 and the lower limit of quantification (LLOQ) was 0.175 and 8.59 nmol/ml respectively. The average recovery (%) was 95.55 for pseudouridine and 97.82 for creatinine by addition and 93.16 and 89.79 % by dilution. The estimation of the coefficients of variation were < 8% for all levels. Conclusions: A positive correlation was found between expected and observed values (Pearson correlation coefficient = 0.99 for pseudouridine and 0.99 for creatinine). A correlation was found between recovery of pseudouridine and recovery of creatinine (Pearson correlation coefficient = 0.86). This method was used to assess pseudouridine excretion in 30 healthy subjects (18 non-smokers and 12 smokers). There were no statistically differences between non-smokers and smokers (AU)

Introdución: La excreción de pseudouridina, está incrementada en procesos inflamatorios relacionados con pérdida de masa muscular encontradaen pacientes con afectación pulmonar. Material y Métodos: Se desarrolla y valida, un método, mediante HPLC, para la determinación simultanea de pseudouridina y creatinina en orina. Como fase estacionaria se utilizó una columna LiCHrospher® 100 RP-18 (5 μm) LiCHroCART® 250-4 (Merck). Fase móvil consistente en un tampón fosfato 0,01 M (pH = 6,1) conteniendo octanosulfónico 3mmol como agente de par iónico, y longitud de onda de 250 nm. La preparación de la muestra se basa en una dilución y filtración. La linealidad del método fue satisfactoria dentro del rango de concentración de 0,23-22,5 nmol/ml para pseudouridina y 1,45-1100 nmol/ml para creatinina, con límites de cuantificación de 0,175 y 8,59 nmol/ml, respectivamente. Resultados: La recuperación media fue del 95,55% para Pseudouridina y del 97,82% para Creatinina en la validación de adición de estándar interno y de 93,16 y 89,79% en la de dilución. Los coeficientes de variación fueron < del 8% en todos los niveles. Se encontró una correlación entre los valores encontrados y los esperados (coeficiente de correlación de Pearson de 0,99). Conclusiones: Existe correlación entre las recuperaciones de pesudouridina y creatinina, coeficiente de correlación de Pearson de 0,86. El método desarrollado, es rápido, sensible y selectivo para la simultanea determinación de pseudouridina y creatinina en orina humana. En este estudio preliminar con 30 voluntarios sanos, 18 no fumadores y 12 fumadores, no se han encontrado diferencias estadísticamente significativas entre ambos grupos con respecto a la excreción de pseudouridina (AU)

Síndrome de diabetes de herencia materna y sordera / Maternally inherited diabetes and deafness: a case report

El síndrome de diabetes de herencia materna y sordera es una causa infrecuente de hipoacusia neurosensorial de origen genético, causado por mutación en el ADN mitocondrial. Se caracteriza por diabetes mellitus de herencia materna e hipoacusia neurosensorial en relación con distrofia macular, manifestaciones neuromusculares o psiquiátricas, miocardiopatía e insuficiencia renal. Presentamos el caso de un paciente que acude a la consulta por hipoacusia y presenta el síndrome de diabetes de herencia materna y sordera (AU)

Maternally inherited diabetes and deafness (MIDD) syndrome is a rare disease associated with progressive sensorineural deafness due to a mitochondrial DNA mutation. Characterized by diabetes mellitus and sensorineural hearing impairment; MIDD is also associated with macular dystrophy, neuromuscular and psychiatric manifestations, cardiomyopathy as well as renal insufficiency. We report the case of a 55-year-old male patient complaining of hearingloss with maternally inherited diabetes and deafness syndrome (AU)

Recent findings in the modern RNA world

It is assumed that modern life forms arose from a molecular ancestor in which RNA molecules both stored genetic information and catalyzed biochemical reactions. In modern cells, these functions are carried out, respectively, by DNA and proteins, but diverse cellular RNAs are also involved in key cellular functions. In this paper, we review the cellular RNAs that are ubiquitous and/or that perform essential biological functions, and we discuss the evolutionary relationships of such RNAs with a prebiotic RNA world. This unexpected biological diversity of cellular RNAs and the crucial functions they perform in cellular metabolism demonstrate the complexity of an RNA-driven metabolism in an ancient RNA world and in modern life. Cellular RNAs are involved in translation (tRNA and rRNA) but also in ribosome maturation (snoRNA) and more generally in RNA processing (snRNA and snoRNA), replication ( telomerase RNA), editing, protein translocation (SRP RNA), cellular transport (vRNA) and translation quality control (tmRNA). In addition, the function of many other cellular RNAs has not yet been determined. Future investigations of RNA function will allow us to better understand not only early evolutionary biological processes but also the central metabolism of modern cells (AU)

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