Precipitado negro en nutrición parenteral / Black precipitate in parenteral nutrition

Introducción: durante la infusión de una nutrición parenteral sin lípidos se observó un precipitado negro en el filtro. Hay hallazgos similares publicados en los que se han detectado cobre y azufre (proveniente de la cisteína) en la composición del precipitado. Objetivo: comprobar que la cisteína y el cobre intervienen en la formación del precipitado. Métodos: se tomaron muestras de la solución de nutrición parenteral antes y después de su paso por el filtro. Se analizaron en ambas muestras las concentraciones de aminoácidos mediante cromatografía de intercambio iónico y derivatización post-columna con ninhidrina en un equipo Biochrom 30 y las de cobre mediante espectrometría de absorción atómica en un equipo PerkinElmer AAnalyst(TM) 200. Resultados: las concentraciones de cisteína y cobre en la solución disminuyeron en un 29,3% y 75,9%, respectivamente. Conclusiones: la disminución de las concentraciones de cisteína y cobre en la solución filtrada sugieren que ambos están involucrados en la formación del precipitado negro observado en el filtro

Introduction: a black precipitate was observed in the filter during the infusion of a parenteral nutrition without lipids. There are similar findings published in which copper and sulphur (from cysteine) were found in the composition of the precipitate. Objective: to determine if copper and cysteine are involved in the formation of the precipitate. Methods: samples of the parenteral nutrition solution were taken before and after its passage through the filter. Amino acids concentrations were analysed in both samples by ion exchange chromatography and post-column derivatization with ninhydrin in a Biochrom 30 device. Copper concentrations were measured by atomic absorption spectrometry in a PerkinElmer AAnalyst(TM) 200 device. Results: a decrease in cysteine concentration of 29.3% was found. The concentration of copper decreased by 75.9%. Conclusions: the decrease in the concentrations of cysteine and copper in the filtered solution suggest that both are involved in the formation of the black precipitate observed in the filter

[Black precipitate in parenteral nutrition]. / Precipitado negro en nutrición parenteral.

INTRODUCTION: Introduction: a black precipitate was observed in the filter during the infusion of a parenteral nutrition without lipids. There are similar findings published in which copper and sulphur (from cysteine) were found in the composition of the precipitate. Objective: to determine if copper and cysteine are involved in the formation of the precipitate. Methods: samples of the parenteral nutrition solution were taken before and after its passage through the filter. Amino acids concentrations were analysed in both samples by ion exchange chromatography and post-column derivatization with ninhydrin in a Biochrom 30 device. Copper concentrations were measured by atomic absorption spectrometry in a PerkinElmer AAnalyst™ 200 device. Results: a decrease in cysteine concentration of 29.3% was found. The concentration of copper decreased by 75.9%. Conclusions: the decrease in the concentrations of cysteine and copper in the filtered solution suggest that both are involved in the formation of the black precipitate observed in the filter.

INTRODUCCIÓN: Introducción: durante la infusión de una nutrición parenteral sin lípidos se observó un precipitado negro en el filtro. Hay hallazgos similares publicados en los que se han detectado cobre y azufre (proveniente de la cisteína) en la composición del precipitado. Objetivo: comprobar que la cisteína y el cobre intervienen en la formación del precipitado. Métodos: se tomaron muestras de la solución de nutrición parenteral antes y después de su paso por el filtro. Se analizaron en ambas muestras las concentraciones de aminoácidos mediante cromatografía de intercambio iónico y derivatización post-columna con ninhidrina en un equipo Biochrom 30 y las de cobre mediante espectrometría de absorción atómica en un equipo PerkinElmer AAnalyst™ 200. Resultados: las concentraciones de cisteína y cobre en la solución disminuyeron en un 29,3% y 75,9%, respectivamente. Conclusiones: la disminución de las concentraciones de cisteína y cobre en la solución filtrada sugieren que ambos están involucrados en la formación del precipitado negro observado en el filtro.

Role of FAST Kinase Domains 3 (FASTKD3) in Post-transcriptional Regulation of Mitochondrial Gene Expression.

The Fas-activated serine/threonine kinase (FASTK) family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domain named RAP (for RNA-binding domain abundant in Apicomplexans), shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2, and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knock-out cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2, and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria.