Ventajas de la utilización del dimetilsulfóxido en la determinación de clorofilas y feofitinas en líquenes

Los pigmentos fotosintéticos de Ramalina fraxinea (L.) Ach. se extraen por trituración ó inmersión del talo con acetona (80%) y dimetilsulfóxido (DMSO). El solvente DMSO es más adecuado que la acetona (80%) para la extracción de clorofilas ya que la extracción es completa y la absorción óptica de los extractos permanece constante durante períodos de tiempos largos

Coeficientes de extinción de clorofilas yfeofitinas (a y b) en DMSO y ecuaciones para el cálculo de sus concentraciones

Se han observado inconsistencias en las fórmulas utilizadas en la determinación de clorofilas (Chl) en dimetilsulfóxido (DMSO), estas fórmulas fueron calculadas para Chl disuelta en acetona (80%). Los coeficientes de extinción (E) de clorofila a (Chl a), clorofila b (Chl b) y feofitina b (Phaeo b) se han obtenido por regresión lineal

Urine collection methods for infants under 3 months of age in clinical practice

Background: Methods of urine collection used in precontinent children are a controversial issue. Definitive diagnosis of urinary tract infection (UTI) requires an uncontaminated urine culture. We aimed to describe methods used to collect urine for culture in infants under 3 months of age and compare results and contamination rates. Methods: This retrospective observational cohort study included 721 urine cultures collected from infants <3 months of age at the Hospital Universitario Infanta Sofía, Madrid, between January 2016 and December 2019. Urine cultures were compared based on collection technique, sex, and patient age. Results: Median patient age was 36 days and 54.6% were male. In total, 592 (82.1%) samples were collected using clean-catch urine stimulation technique (CCUST), 77 (10.7%) by urethral catheterization (UC) and 52 (7.2%) by urine bag (UB). Positive cultures were obtained in 11.7% (95% confidence interval [CI] 9.1, 14.3) of CCUST samples and in 28.6% (95% CI 18.5, 38.7) of UC samples (p<0.001). The contamination rate was 13.7% (95% CI 10.9, 16.4] for CCUST, 23.1% (95% CI 11.6, 34.6) for UB and 5.2% (95% CI 0.2, 10.2) for UC, with statistically significant differences (p=0.007) between UB and UC collection. Conclusions: CCUST is the most commonly used method in our hospital for collecting urine in infants younger than 3 months. The contamination rate of UC is lower but not significantly different to that of CCUST. Urine collection by CCUST serves as a non-invasive alternative to UC for diagnosis of UTI in infants under 3 months of age in routine clinical practice. Graphical abstract.Sin financiación3.654 JCR (2021) Q2, 36/130 Pediatrics0.864 SJR (2021) Q1, 54/320 Pediatrics, Perinatology and Child HealthNo data IDR 2020UE