Display omitted
•Three different LC-MS/MS methods were compared for quantitation of OEA in mice brain tissue.•Generation and degradation of OEA simultaneously occurred in brain homogenate.•Both ...generation and degradation of OEA were inhibited by lowering temperature.•The endogenous striatal OEA level could be used as a potential biomarker for obesity in mice.
Obesity has become a severe public health problem worldwide. An endogenous fatty acid ethanolamine oleoyl ethanolamine (OEA) is reported to be capable of reducing body weight and food intake by increasing striatal extracellular dopamine concentration. However, association between obesity and striatal OEA level remains unknown. As such, it is necessary to develop a sensitive and reliable method to quantitate OEA concentration in striatum. Because true endogenous analytes free blank matrix is not available, surrogate analyte, surrogate matrix and background subtraction methods are often employed for the analysis of endogenous compounds. In this study, three liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were developed and validated for the determination of OEA concentration in mouse brain homogenate. Interestingly, stability results found that OEA-d4 degraded in brain homogenate under room temperature, while OEA level remarkably increased with time. Since lowering temperature could observably decelerate the endogenous transformation of OEA, sample collection and preparation were carried out under ice-bath condition. Hexane: isopropanol (9:1, v/v) was employed as an extractant for liquid-liquid extraction. After method validation, three methods were applied to quantify OEA in striatum homogenate from C57B6/L mice following normal and high fat diet feeding for 4 months. Results from three methods all showed the striatal OEA level in obesity group was significantly higher than control group and obesity-resist group, which indicated that obesity might be associated with elevated striatal OEA level.
The telomere reverse transcriptase promoter (
TERT
p) is frequently mutated in malignant gliomas, particularly glioblastomas (GBM, 85%), and is involved in maintaining telomere length.
TERT
p ...mutations are prognostic for patient survival. Given the evolving use of Infinium DNA methylation arrays in assaying biomarkers in glioma, we aimed to develop an accurate predictor of
TERT
p mutations in gliomas using this platform. We analyzed TCGA lower grade glioma (LGG) and GBM available with both
TERT
p sequencing and Infinium 450k data. Samples were split into training and testing set to determine predictor accuracy. Probes with potential quality issues were excluded and probe selection performed using an elastic net algorithm. Probes were selected across the genome, not limited to the
TERT
p locus. A logistic regression model with binomial distribution was built using the final optimized model, constructed based on 1000 CpG probes, all distinct from
TERT
p. Prediction accuracy was 100% (179/179, AUC=1) in the training set and 97.5% (116/119) in the test set. Comparison of the normalized frequency of selected probes by chromosome revealed enrichment for chromosomes 20 (0.4987%) and 18 (0.4859%). The majority of probes enriched in CpG islands (53.6%), followed by open sea (22.9%), shore (17.4%), and shelf (6.1%). Relative to known genes, probe enrichment occurred predominantly near transcriptional start sites (within 200–1500 bp, 31.0%), followed by gene bodies (26.3%) and intergenic regions (18.3%). Quite unexpectedly, probes within the predictor do not map near
TERT
or other telomere maintenance factors nor fell within known methylation signatures, such as G-CIMP, suggesting that
TERT
p mutation is associated with novel epigenetic changes. Moreover, this biomarker permits rapid and cost effective detection of
TERT
p mutation using the widely used Infinium platform.
Glioblastoma (GBM) has poor prognosis due to ineffective agents and poor delivery methods. MicroRNAs (miRs) have been explored as novel therapeutics for GBM, but the optimal miRs and the ideal ...delivery strategy remain unresolved. In this study, we sought to identify the most effective pan-subtype anti-GBM miRs and to develop an improved delivery system for these miRs.
We conducted an unbiased screen of over 600 miRs against 7 glioma stem cell (GSC) lines representing all GBM subtypes to identify a set of pan-subtype-specific anti-GBM miRs and then used available TCGA GBM patient outcomes and miR expression data to hone in on miRs that were most likely to be clinically effective. To enhance delivery and expression of the miRs, we generated a polycistronic plasmid encoding 3 miRs (pPolymiR) and used HEK293T cells as biofactories to package pPolymiR into engineered exosomes (eExos) that incorporate viral proteins (Gag/VSVg) in their structure (eExos+pPolymiR) to enhance function.
Our stepwise screen identified miR-124-2, miR-135a-2, and let-7i as the most effective miRs across all GBM subtypes with clinical relevance. Delivery of eExos+pPolymiR resulted in high expression of all 3 miRs in GSCs, and significantly decreased GSC proliferation in vitro. eExos+pPolymiR prolonged survival of GSC-bearing mice in vivo when compared with eExos carrying each of the miRs individually or as a cocktail.
eExos+pPolymiR, which includes a pan-subtype anti-glioma-specific miR combination encoded in a polycistronic plasmid and a novel exosome delivery platform, represents a new and potentially powerful anti-GBM therapeutic.
Background
Oral sodium zirconium cyclosilicate (SZC) is a novel potassium binder capable of achieving a rapid reduction of serum potassium (sK
+
) and maintaining a long-term normokalemia. We ...undertook a meta-analysis to summarize and evaluate the effects surrounding SZC in patients with hyperkalemia.
Method
We searched data sources from MEDLINE (from 1950 to Sep 2020), EMBASE (from 1970 to Sep 2020), and the Cochrane Library database (from 1950 to Sep 2020) for eligible studies. All randomized controlled trials (RCTs) regarding comparison of therapeutic effects of SZC in hyperkalemia participants were included.
Results
Seven studies, including 1697 patients with hyperkalemia, were analyzed. SZC significantly reduced mean sK
+
(−0.42 mmol/L; 95% CI: −0.63 to −0.20 mmol/L,
p
= 0.0001) compared with placebo, with a significantly greater proportion of patients with normokalemia (RR 3.48, 95% CI 1.49 to 8.11,
p
= 0.004). Subgroup analyses showed that the longer durations of SZC treatment, the greater magnitudes of potassium reduction when compared with those of placebo (
p
between subgroups = 0.01) at correction phase. Besides, it also demonstrated sK
+
tended to decrease more in patients who got longer treatment or larger dosage of SZC at maintenance phase; however, the difference did not reach statistical significance. Additionally, the drug was equally effective in studies with larger than 50% of patients with chronic kidney disease (CKD) or diabetes or patients using renin-angiotensin aldosterone system inhibitor (RAAS) inhibitors (all
p
< 0.05). The risk of edema (4.30, 1.17 to 15.84;
p
= 0.03) in SZC group was higher than those of placebo group. No statistically significant differences in the risks of other adverse events were observed between the two groups.
Conclusions
SZC effectively decreased the sK
+
level in patients with hyperkalemia within 48 h and had benefits in the long-term control of serum potassium in patients who continued to receive SZC with a favorable safety profile from available data.
Patients with ependymoma exhibit a wide range of clinical outcomes that are currently unexplained by clinical or histological factors. Little is known regarding molecular biomarkers that could ...predict clinical behavior. Since recent data suggest that these tumors display biological characteristics according to their location (cerebral vs. infratentorial vs. spinal cord), rather than explore a broad spectrum of ependymoma, we focused on molecular alterations in ependymomas arising in the infratentorial compartment. Unsupervised clustering of available
g
ene expression microarray data revealed two major subgroups of infratentorial ependymoma. Group 1 tumors over expressed genes that were associated with mesenchyme, Group 2 tumors showed no distinct gene ontologies. To assess the prognostic significance of these gene expression subgroups, real-time reverse transcriptase polymerase chain reaction assays were performed on genes defining the subgroups in a training set. This resulted in a 10-gene prognostic signature. Multivariate analysis showed that the 10-gene signature was an independent predictor of recurrence-free survival after adjusting for clinical factors. Evaluation of an external dataset describing subgroups of infratentorial ependymomas showed concordance of subgroup definition, including validation of the mesenchymal subclass. Importantly, the 10-gene signature was validated as a predictor of recurrence-free survival in this dataset. Taken together, the results indicate a link between clinical outcome and biologically identified subsets of infratentorial ependymoma and offer the potential for prognostic testing to estimate clinical aggressiveness in these tumors.
Many power distribution systems have been operated with neutral ineffectively earthed, and earth fault current is no more than a few tens of amperes. Traditional earth fault detection methods based ...on zero sequence current has poor precision and sensitivity in this case. For improvement, a novel principle for feeder grounding fault protection based on fuzzy clustering algorithms is presented in this paper. First, the historical data are divided into two groups by fuzzy clustering algorithms. The space relative distance among detected pattern and two cluster centers is then calculated to discriminate the faulted feeder. It can detect high impedance grounding faults (HIGF). The scheme has been verified by EMTP simulation, and results show that the proposed scheme always trips all kinds of grounding faults with high sensitivity and robustness in neutral ineffectively earthed power systems (NIEPS).
PDF
