The Dose-Dependent Effect of Nesiritide on Renal Function in Patients with Acute Decompensated Heart Failure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Conflicting renal effects of nesiritide have been reported in patients with acute decompensated heart failure. To answer this controversy, we performed a meta-analysis of randomized controlled trials to evaluate the influence of nesiritide on renal function in patients with acute decompensated heart failure.

Methods

Articles were obtained from PubMed, Medline, Cochrane Library and reference review. Randomized controlled studies that investigated the effects of continuous infusion of nesiritide on renal function in adult patients with acute decompensated heart failure were included and analyzed. Fixed-effect model was used to estimate relative risk (RR) and weight mean difference (WMD). The quality assessment of each study, subgroup, sensitivity, and publication bias analyses were performed.

Results

Fifteen randomized controlled trials were eligible for inclusion. Most of included studies had relatively high quality and no publication bias was found. Overall, compared to control therapies, nesiritide might increase the risk of worsening renal function in patients with acute decompensated heart failure (RR 1.08, 95% CI 1.01–1.15, P = 0.023). In subgroup analysis, high-dose nesiritide strongly associated with renal dysfunction (RR 1.54, 95% CI 1.19-2.00, P = 0.001), but no statistical differences were observed in standard-dose (RR 1.04, 95% CI 0.98-1.12, P = 0.213), low-dose groups (RR 1.01, 95% CI 0.74-1.37, P = 0.968) and same results were identified in the subgroup analysis of placebo controlled trials. Peak mean change of serum creatinine from baseline was no significant difference (WMD -2.54, 95% CI -5.76-0.67, P = 0.121).

Conclusions

In our meta-analysis, nesiritide may have a dose-dependent effect on renal function in patients with acute decompensated heart failure. High-dose nesiritide is likely to increase the risk of worsening renal function, but standard-dose and low-dose nesiritide probably have no impact on renal function. These findings could be helpful to optimize the use of nesiritide in clinical practice.     

Modeling changes in probabilistic reinforcement learning during adolescence

In the real world, many relationships between events are uncertain and probabilistic. Uncertainty is also likely to be a more common feature of daily experience for youth because they have less experience to draw from than adults. Some studies suggest probabilistic learning may be inefficient in youths compared to adults, while others suggest it may be more efficient in youths in mid adolescence. Here we used a probabilistic reinforcement learning task to test how youth age 8-17 (N = 187) and adults age 18-30 (N = 110) learn about stable probabilistic contingencies. Performance increased with age through early-twenties, then stabilized. Using hierarchical Bayesian methods to fit computational reinforcement learning models, we show that all participants’ performance was better explained by models in which negative outcomes had minimal to no impact on learning. The performance increase over age was driven by 1) an increase in learning rate (i.e. decrease in integration time scale); 2) a decrease in noisy/exploratory choices. In mid-adolescence age 13-15, salivary testosterone and learning rate were positively related. We discuss our findings in the context of other studies and hypotheses about adolescent brain development.     

猪链球菌1、2、14、1/2型荚膜多糖的单糖组成比较

【目的】猪链球菌1、2、14和1/2型间存在单向或双向的交叉抗原性,这种交叉抗原性的产生原因至今未被揭示。【方法】采用Sephacryl S-300凝胶层析柱对猪链球菌14和1/2型荚膜多糖进行分离纯化,经苯酚-硫酸检测和dot-ELISA辅助鉴定,确定荚膜多糖成分。采用高效凝胶渗透色谱法测定14和1/2型猪链球菌荚膜多糖分子量分别为487.38 kDa和512.72 kDa。【结果】经柱前衍生高效液相色谱法、荧光标记液相色谱法和核磁共振测定14和1/2型猪链球菌荚膜多糖单糖组成分别为:Glc/Gal/GlcNAc/Rha/Neu5Ac(1∶2.94∶1.35∶0.24∶0.37)和Glc/Gal/GlcNAc/GalNAc/Rha/Neu5Ac(1∶1.67∶1.05∶0.93∶0.72∶0.7)。并与已知的猪链球菌1、2型荚膜多糖的单糖组成进行比较分析,发现4种血清型荚膜多糖都具有Glc、GlcNAc、Gal和Neu5Ac,但单糖组成和比列并无明显相似性,这种交叉抗原性可能是由于荚膜多糖的空间结构相似性和(或)细胞表面的其他成分引起的。     

Acidolysis-based component mapping of glycosaminoglycans by reversed-phase high-performance liquid chromatography with off-line electrospray ionization–tandem mass spectrometry: Evidence and tags to distinguish different glycosaminoglycans

Diverse monosaccharide analysis methods have been established for a long time, but few methods are available for a complete monosaccharide analysis of glycosaminoglycans (GAGs) and certain acidolysis-resistant components derived from GAGs. In this report, a reversed-phase high-performance liquid chromatography (RP–HPLC) method with pre-column 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization was established for a complete monosaccharide analysis of GAGs. Good separation of glucosamine/mannosamine (GlcN/ManN) and glucuronic acid/iduronic acid (GlcA/IdoA) was achieved. This method can also be applied to analyze the acidolysis-resistant disaccharides derived from GAGs, and the sequences of these disaccharides were confirmed by electrospray ionization–collision-induced dissociation–tandem mass spectrometry (ESI–CID–MS/MS). These unique disaccharides could be used as markers to distinguish heparin/heparan sulfate (HP/HS), chondroitin sulfate/dermatan sulfate (CS/DS), and hyaluronic acid (HA).     

Involvement of androgen receptor and glucose-regulated protein 78 kDa in human hepatocarcinogenesis

Previous studies demonstrated that androgen receptor (AR) is expressed in human hepatocellular carcinoma (HCC), one of the male-dominant diseases. Glucose-regulated protein 78 kDa (GRP78/Bip), which has a role in cancer development, is one of the androgen response genes in prostate cell lines. The aim of this study was to investigate the impact of AR on endoplasmic reticulum (ER)-stress signaling in human hepatoma. AR and GRP78 expressions were examined in human liver tissue panels. Human hepatoma cells stably expressing short hairpin RNA targeting AR and cells over-expressing AR were generated. The expressions of ER-stress molecules and AR were measured by real-time RT-PCR and Western blotting. The effect of AR on ER-stress responsive gene expression was examined by reporter assay. Strong positive correlation between AR mRNA and GRP78 mRNA was observed in stage I/II-HCCs. AR enhanced ER-stress responsive element activities and GRP78 expression, and regulated ER-stress response in hepatocytes. Sorafenib strongly induced significant apoptosis in HepG2 cells by the inhibition of AR and inhibition of the downstream GRP78. AR seems a co-regulator of GRP78 especially in earlier-stage HCC. AR plays a critical role in controlling ER-stress, providing new therapeutic options against HCC.     

Isolation and characterization of novel Glu-St1 alleles from Pseudoroegneria spicata and Pd. strigosa

Pseudoroegneria is a small genus of the Triticeae tribe; its St genome is present in over half of allopolyploid Triticeae species. The high molecular weight (HMW) subunits of glutenin (GS) encoded by the St genome are not well described. In this paper, we report the characterization of fourteen alleles of HMW-GS genes from the two species Pd. spicata and Pd. strigosa. Analysis shows that all fourteen sequences possess a typical primary structure shared by other known HMW-GS, but with some unique modifications. All fourteen Glu-St1 alleles are significantly smaller than normal Glu-1 genes due to fewer repeat motifs in a repetitive region with no indication of large deletion in other conserved regions. Thus, the small size is a common feature of HMW-GS encoded by Glu-St1 loci of Pseudoroegneria species. Sequence analysis indicated that all fourteen Glu-St1 alleles were intermediate type between x- and y-type, which represent an intermediate stage in the evolutionary divergence of x- and y-type subunits.     

The Effect of Mutation and Selection on Codon Adaptation in Escherichia coli Bacteriophage

Studying phage codon adaptation is important not only for understanding the process of translation elongation, but also for reengineering phages for medical and industrial purposes. To evaluate the effect of mutation and selection on phage codon usage, we developed an index to measure selection imposed by host translation machinery, based on the difference in codon usage between all host genes and highly expressed host genes. We developed linear and nonlinear models to estimate the C→T mutation bias in different phage lineages and to evaluate the relative effect of mutation and host selection on phage codon usage. C→T-biased mutations occur more frequently in single-stranded DNA (ssDNA) phages than in double-stranded DNA (dsDNA) phages and affect not only synonymous codon usage, but also nonsynonymous substitutions at second codon positions, especially in ssDNA phages. The host translation machinery affects codon adaptation in both dsDNA and ssDNA phages, with a stronger effect on dsDNA phages than on ssDNA phages. Strand asymmetry with the associated local variation in mutation bias can significantly interfere with codon adaptation in both dsDNA and ssDNA phages.     

Palmitoylation of STREX domain confers cerebroside sensitivity to the BKCa channel

Our previous study reported that cerebrosides from traditional Chinese medicine Baifuzi directly interact with the STREX domain of BK_Ca channels, which in turn results in the therapeutic effect of Baifuzi on ischemic stroke. However, it is not known how cerebrosides in the plasma membrane could interact with the STREX domain that is in the cytoplasmic side. Using patch-clamp technique, effects of different cerebrosides on the BK_Ca channel were studied by measuring single channel currents in CHO cells expressing wild type or mutated BK_Ca channels. Palmitoylation of the STREX domain was removed either by site-directed mutagenesis or pharmacological inhibition. Removal of palmitoylation sites at C646 and C647 by mutating the residues to Ala abolished the ability of cerebrosides to activate the BK_Ca channel. In contrast, the mutation neither changed the single channel conductance nor voltage sensitivity of the channel. Both palmitoylation inhibitors tunicamycin and palmitic acid analog 2-bromopalmitate attenuated the activation of the BK_Ca channel by cerebrosides. Furthermore, confocal images on STREX-EGFP fragments demonstrated that STREX fragments no longer associated with the plasma membrane when the palmitoylation was removed or blocked. These findings suggest that palmitoylation of the STREX domain is necessary for cerebrosides to activate the BK_Ca channel and provide insight into the mechanism of how Baifuzi could exert therapeutic effect on ischemic stroke.     

Cholesterol modulates function of connexin 43 gap junction channel via PKC pathway in H9c2 cells

It has been shown that cholesterol modulates activity of protein kinase C (PKC), and PKC phosphorylates connexin 43 (Cx43) to regulate its function, respectively. However, it is not known whether cholesterol modulates function of Cx43 through regulating activity of PKC. In the present study, we demonstrated that cholesterol enrichment reduced the dye transfer ability of Cx43 in cultured H9c2 cells. Western blot analysis indicated that cholesterol enrichment enhanced the phosphorylated state of Cx43. Immunofluorescent images showed that cholesterol enrichment made the Cx43 distribution from condensed to diffused manner in the interface between the cells. In cholesterol enriched cells, PKC antagonists partially restored the dye transfer ability among the cells, downregulated the phosphorylation of Cx43 and redistributed Cx43 from the diffused manner to the condensed manner in the cell interface. In addition, reduction of cholesterol level suppressed PKC activity to phosphorylate Cx43 and restored Cx43 function in PKC agonist-treated cells. Furthermore, we demonstrated that cholesterol enrichment upregulated the phosphorylated state of Cx43 at Ser368, while PKC antagonists reversed the effect. Taken together, cholesterol level in the cells plays important roles in regulating Cx43 function through activation of the PKC signaling pathway.