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Acute stroke management is critically time-sensitive and challenging. Blood-based biomarkers that can differentiate acute ischemic stroke (IS) from hemorrhagic stroke (HS) can greatly facilitate triage and early management. Admission blood samples obtained within 6 h of stroke symptom onset were analyzed in a derivation/validation design. GFAP, N-FL, NT-proBNP, copeptin, neutrophils (%), NLR, and platelet counts were assessed in the derivation cohort. The informative markers and the derived cutoff values were evaluated in the validation cohort. GFAP > 703 pg/mL showed a PPV of 76.9% and NPV of 95.8% for differentiating HS from IS. Multiple logistic regression analysis showed that GFAP and NT-proBNP were independent variables associated with IS and HS differentiation. Furthermore, applying a combined cutoff (GFAP > 703 pg/mL and NT-proBNP ≤ 125 pg/mL) for HS detection increased the PPV in both the derivation and validation cohorts (93.3% and 100%, respectively). GFAP and NT-proBNP levels were validated as informative blood biomarkers in the differentiation of IS and HS and using a combination of GFAP and NT-proBNP is suggested as a feasible strategy to differentiate stroke subtypes in the hyperacute phase of stroke. [ABSTRACT FROM AUTHOR]

Background: A pilot external quality assurance (EQA) survey for the free light chain (FLC) assay was developed and implemented in Korea. Methods: Survey data over 6 years (2010–2015) were collected retrospectively and Sigma metrics were calculated for method-specific peer groups. Results: Nineteen to 29 laboratories participated in the EQA survey, and nephelometric (20%) and turbidimetric (80%) methods were used. Using a previously published clinically relevant reference change value (RCV) of 54.5% as the tolerance limit, the method-specific median Sigma metrics of kappa (κ) and lambda (λ) FLC achieved greater than Three-Sigma for 86–97% of all EQA distributions, and Five-Sigma for 48–72% of all distributions. Conclusions: This EQA analysis of FLC assay applied clinically relevant quality specifications using Sigma metrics. During the 6-year EQA survey, we found that most of the results from participating laboratories meet clinically relevant quality specifications. In addition, method-specific differences were noted for λ FLC, at FLC concentrations above the initial measuring range that require a sample dilution. [ABSTRACT FROM AUTHOR]

Enfuvirtide (ENF) is a peptide medicine clinically used for the treatment of HIV infections. The outcome shows that mesoporous HSNs having pores that are thought to be larger than ENF are better substances for the ingression of ENF with MW = 4492.1 g/mol than microporous HSNs. HPSNs that can internally keep peptide medicine like ENF can provide the peptide with good protection from external protease digestion, which are generally considered as 10 times bigger than peptides, reduce the biodegradability of the medicine, and maintain the remedial effect longer. They are not so different from that of ENF lane in which ENF amount is 10 g. Therefore, ENF was consistently released from HPSN every about 8-10% after 14, 19, and 33 days. [Extracted from the article]

M1 RNA, the gene product of rnpB, is the catalytic subunit of RNase P in Escherichia coli. M1 RNA is transcribed from a proximal promoter as pM1 RNA, a precursor M1 RNA, and then is processed at its 3' end by RNase E. In addition to pM1 RNA, large rnpB-containing transcripts are produced from unknown upstream promoters. However, it is not known yet how these large transcripts contribute to M1 RNA biosynthesis. To examine their biological relevance to M1 RNA biosynthesis, we constructed a model upstream transcript, upRNA, and analyzed its cellular metabolism. We found that upRNA was primarily degraded rather than processed to M1 RNA in the cell and that this degradation occurred in RNase E-dependent manner. The in vitro cleavage assay with the N-terminal catalytic fraction of RNase E showed that the M1 RNA structural sequence in upRNA was much more vulnerable to the enzyme than the sequence in pM1 RNA. Considering that RNase E is a processing enzyme involved in 3' end formation of M1 RNA, our results imply that this enzyme plays a dual role in processing and degradation to achieve tight control of M1 RNA biosynthesis.

The Kin.46 ribozyme catalyzes transfer of the gamma (thio)phosphoryl group of ATP (or ATPgammaS) to the ribozyme's 5' hydroxyl. Single-turnover catalytic activities of topologically rearranged versions of Kin.46 were studied to gain insight into its overall tertiary architecture. The distal ends of stems P3 and P4 were tethered through a single-stranded connection domain that altered the interhelical connectivity. The shortest linkers interfered with catalysis, while seven or more nucleotides (nt) in the linker allowed near-normal catalytic rates, suggesting that a distance of roughly 25-35 A optimally separates the termini of these helices. Activity was maximal when the tether contained 15 nt, at which point the k(cat) (0.016 min(-1)) and Km (1.2 mM) values were identical to those of a nontethered control. The presence of the tether alters Mg(2+) dependence, in that Mg2+ binding appears to be more cooperative in the tethered ribozyme (Hill coefficient 1.4-1.8 versus 0.8 for the nontethered ribozyme). Binding affinity for the ATPgammaS substrate increases at elevated concentrations of Mg2+, particularly for the tethered ribozyme. The tethered ribozyme displays significantly enhanced thermal stability, with a maximum initial velocity (0.126 min(-1)) at 60 degrees C, whereas the nontethered ribozyme has a lower maximum initial velocity (0.051 min(-1)) at 50 degrees C. The tether also significantly reduces the apparent entropy of activation. Both of these effects can be understood in terms of stabilization of the ribozyme in a conformation that is on-path with respect to catalysis, and in terms of facilitating formation of the allosteric activation helix P4.