Exosome-like extracellular vesicles (ELVs) contain biomolecules that have potential as diagnostic biomarkers, such as proteins, micro-RNAs (miRNAs), and lipids. However, it is difficult to enrich ELVs consistently with high yield and purity from clinical samples, which hampers the development of ELV biomarkers. This is particularly true for miRNAs in protein-rich plasma. Hence, we modified ELV isolation protocols of three commercially available polymer-precipitation-based kits using proteinase K (PK) treatment to quantify ELV-associated miRNAs in human plasma. We compared the yield, purity, and characteristics of enriched plasma ELVs, and measured the relative quantity of three selected miRNAs (miR-30c, miR-126, and miR-192) in ELVs using six human plasma samples. Compared with the original protocols, we demonstrated that ELVs can be isolated with PK treatment with high purity (i.e., lack of non-exosomal proteins and homogeneous size of vesicles) and yield (i.e., abundancy of exosomal markers), which were dependent on kits. Using the kit with the highest purity and yield with PK treatment, we successfully quantified ELV miRNAs (levels of 45%–65% in total plasma) with acceptable variability. Collectively, ELV enrichment using the modified easy-to-use method appears suitable for the analysis of miRNAs, although its clinical applicability needs to be confirmed in larger clinical studies.
ObjectiveWe investigated the characteristics of pediatric emergency department (ED) patients in Korea and determined factors associated with hospital admission after ED treatment.MethodsKorea Health Panel data from 2008 through 2013 were analyzed retrospectively; we included patients under 18 years old who visited the ED at least once. We collected patient and household epidemiologic data such as sex, age group, region of residence, disability, chronic disease, household income quintile, national health insurance type, use of private insurance, and annual frequency of ED visits. We also examined data related to each ED visit, such as reason for visit, medical service provided, and hospital size/ownership. We then investigated which factors were correlated with case disposition (discharge home or hospital admission) after ED treatment.ResultsIn total, 3,160 pediatric ED visits occurred during the six-year period. Males (57.5%) and children aged 0–5 years (47.7%) made more visits than females and older children, respectively. The proportion of ED visits for disease (67.7%) was much higher than for injury or poisoning (32.2%), and 452 cases (14.3%) required hospital admission. For hospital admission, the odds ratio (OR) of females was 0.73 compared to males, and the OR of children aged 6–11 was 0.68 compared to children aged 0–5. The OR of capital residents was 0.69 compared to province residents, and the OR of the highest income quintile was 0.51 compared to the lowest quintile. The OR of children with private insurance coverage was 0.49 compared to those lacking private insurance, and the OR of ED visits due to disease was 1.82 compared to visits due to injury/poisoning.ConclusionThis analysis of clinical and demographic characteristics of pediatric ED visits and hospital admissions can serve as the foundation of future prospective studies required for establishing appropriate policies for the Korean pediatric emergency medical system.
The 5'-AMP-activated protein kinase (AMPK), which is a sensor of cellular energy, regulates neuronal survival and energy homeostasis. However, the roles of AMPK in the pathogenesis of Alzheimer's disease (AD) are unclear. The senescence-accelerated mouse prone 8 (SAMP8) strain is characterized by deficits in learning and memory, exhibits pathological characteristics of AD as early as 5 months of age, and is being increasingly recognized as a model of AD. Here, we investigated the relationship between AMPK activation and phosphorylation of the tau protein in the brain of young (2-month-old) SAMP8 animals and in differentiated SH-SY5Y cells. Upregulation of p-AMPK, p-ACC, and p-GSK3βS9 and downregulation of p-tau396 and sirtuin 1 (Sirt1) were observed in the cerebral cortex of young SAMP8 mice compared with that of age-matched SAMR1 animals. The hippocampal levels of p-AMPK and p-tau396 in SAMP8 animals were not significantly different from those of SAMR1, whereas upregulation of p-GSK3βS9 and downregulation of sirt1 was observed in the hippocampus of SAMP8 mice. Consistent with in vivo findings in the cortex, AMPK activation in SH-SY5Y cells upregulated p-GSK3βS9 but downregulated p-tau396, whereas it had no significant effect on p-tau262 expression. In addition, the AMPK-mediated inhibition of p-tau396 expression was attenuated by okadaic acid, a protein phosphatase 2A (PP2A) inhibitor. Taken together, our data showed that AMPK activation inhibits p-tau396 expression in a GSK3β- and PP2A-dependent manner, and suggest that differential regulation of tau phosphorylation in young SAMP8 mice by AMPK plays a compensatory role against accelerated senescence in this AD animal model.
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