Background: Risk factors for PICC CLABSI (peripherally inserted central venous catheter/ central line associated bloodstream infections) have been evaluated in a limited number of prospective and retrospective studies with conflicting results. Methods: A six year retrospective review of PICC CLABSI within a single institution was performed. PICC CLABSI cases were matched to uninfected controls and host and device data were extracted from comprehensive medical record reviews. A statistical analysis of PICC CLABSI risk factors compared to matched controls was performed. Results: 6756 patients had a PICC line placed during the study period (January 1, 2008 - December 31, 2013). Fifty-six (0.83%) CLABSI were identified and matched to 245 uninfected controls. Factors associated with PICC CLABSI included: sepsis (P<0.0001), history of smoking (P=0.002), hyperlipidemia (P=0.048), duration of PICC (P<0.0001), area of insertion (P=0.019), use of de-clotting agents ( P=0.0009), complication after PICC line insertion (P=0.0008), and use of anti-MRSA antibiotics after PICC insertion ( P=0.006). In multivariant analysis, there was a significant association between PICC CLABSI and sepsis (OR=4.9, CI 2.2-11.1), history of smoking (OR=2.9, CI 1.3 – 6.2) and gastrostomy (OR =6.5, CI 2.2 – 19.4). Conclusions: Risk factors for PICC CLABSI in an institution with low rates of infection include both host factors (sepsis, smoking, gastrostomy tube) and device factors (area of insertion, complications, use of de-clotting agents, anti-MRSA antibiotics after PICC placement, and PICC duration). Preventative measures targeting modifiable risk factors may decrease rates of PICC CLABSI in the future.
Adopting an interdisciplinary approach, this book investigates the style, or 'voice,' of English language translations of twentieth-century Latin American writing, including fiction, political speeches, and film. Existing models of stylistic analysis, supported at times by computer-assisted analysis, are developed to examine a range of works and writers, selected for their literary, cultural, and ideological importance. The style of the different translators is subjected to a close linguistic investigation within their cultural and ideological framework.
The poly(A)-binding protein (PABP) binds to the poly(A) tail of eukaryotic cellular mRNAs and contributes to their stability and translational efficiency. In plants, PABP is expressed from an unusually large gene family grouped into 3 classes that expanded during the evolution of land plants. Subsequent to expansion of the family, members diverged in their primary sequence and in expression. Further expansion of the family and divergence of its members in the Brassicaceae demonstrate the continued dynamic evolution of PABP in plants. In this study, the function of the widely-expressed class II PABP family members was examined to determine how individual class II members contribute to plant growth and development. Of the 3 class II PABP members, PAB2 and PAB4 contribute most to vegetative growth and vegetative-to-floral transition whereas PAB2, and the recently-evolved third class II member, PAB8, contribute to inflorescence and silique growth. Interestingly, although class I and class III PABP members are expressed specifically in reproductive organs, class II PABP members are also necessary for fertility in that the combinatorial loss of PAB2 and either PAB4 or PAB8 expression resulted in reduced fertility. Although all 3 class II members are required for protein expression, PAB4 contributes most to the steady-state level of a reporter mRNA and to protein expression. These findings suggest that class II PABP members are partially overlapping in function but also involved in distinct aspects of plant growth and development.
Interactions between RNA binding protein (RBP) and mRNAs are critical to post-transcriptional gene regulation. Eukaryotic genomes encode thousands of mRNAs and hundreds of RBPs. However, in contrast to interactions between transcription factors (TFs) and DNA, the interactome between RBPs and RNA has been explored for only a small number of proteins and RNAs. This is largely because the focus has been on using ‘protein-centered’ (RBP-to-RNA) interaction mapping methods that identify the RNAs with which an individual RBP interacts. While powerful, these methods cannot as of yet be applied to the entire RBPome. Moreover, it may be desirable for a researcher to identify the repertoire of RBPs that can interact with an mRNA of interest – in a ‘gene-centered’ manner, yet few such techniques are available. Here, we present Protein-RNA Interaction Mapping Assay (PRIMA) with which an RNA ‘bait’ can be tested versus multiple RBP ‘preys’ in a single experiment. PRIMA is a translation-based assay that examines interactions in the yeast cytoplasm, the cellular location of mRNA translation. We show that PRIMA can be used with small RNA elements, as well as with full-length Caenorhabditis elegans 3′UTRs. PRIMA faithfully recapitulates numerous well-characterized RNA-RBP interactions and also identified novel interactions, some of which were confirmed in vivo . We envision that PRIMA will provide a complementary tool to expand the depth and scale with which the RNA-RBP interactome can be explored.
Reconstituted cell-free protein synthesis systems such as the Protein synthesis Using Recombinant Elements (PURE) system give high-throughput and controlled access to in vitro protein synthesis. Here we show that compared with the commercial S30 crude extract based RTS 100 E. coli HY system, the PURE system has less mRNA degradation and produces up to ∼6-fold full-length proteins. However the majority of polypeptides PURE produces are partially translated or inactive since the signal from firefly luciferase (Fluc) translated in PURE is only ∼2/3rd of that measured using the RTS 100 E. coli HY S30 system. Both of the 2 batch systems suffer from low ribosome recycling efficiency when translating proteins from 82 kD to 224 kD. A systematic fed-batch analysis of PURE shows replenishment of 6 small molecule substrates individually or in combination before energy depletion increased Fluc protein yield by ∼1.5 to ∼2-fold, while creatine phosphate and magnesium have synergistic effects when added to the PURE system. Additionally, while adding EF-P to PURE reduced full-length protein translated, it increased the fraction of functional protein and reduced partially translated protein probably by slowing down the translation process. Finally, ArfA, rather than YaeJ or PrfH, helped reduce ribosome stalling when translating Fluc and improved system productivity in a template-dependent fashion.
Radiation-induced gene expression has long been hypothesized to protect against cell death. Defining this process would provide not only insight into the mechanisms mediating cell survival after radiation exposure, but also a novel source of targets for radiosensitization. However, whereas the radiation-induced gene expression profiles using total cellular mRNA have been generated for cell lines as well as normal tissues, with few exception, the changes in mRNA do not correlate with changes in the corresponding protein. The traditional approach to profiling gene expression, i.e., using total cellular RNA, does not take into account posttranscriptional regulation. In this review, we describe the use of gene expression profiling of polysome-bound RNA to establish that radiation modifies gene expression via translational control. Because changes in polysome-bound mRNA correlate with changes in protein, analysis of the translational profiles provides a unique data set for investigating the mechanisms mediating cellular radioresponse.
The tRNA for the 21st proteinogenic amino acid, selenocysteine, exists in mammalian cells as 2 isoforms differing by a single 2'-O-methylribosyl moiety at position 34 (Um34). These isoforms contain either 5-methoxycarbonylmethyluridine (mcm5U) or 5-methoxycarbonylmethyl-2'-O-methyluridine (mcm5Um) at position 34. The accumulation of the mcm5Um isoform is tightly correlated with the expression of nonessential "stress response" selenoproteins such as glutathione peroxidase 1 (GPX1). The expression of essential selenoproteins, such as thioredoxin reductase 1 (TXNRD1), is not affected by changes in Sec-tRNA[Ser]Sec isoform accumulation. In this work we used purified mcm5U and mcm5Um Sec-tRNA[Ser]Sec isoforms to analyze possible differences in binding to the selenocysteine-specific elongation factor, EEFSEC, and the translation of GPX1 and TXNRD1in vitro. Our results indicate that no major distinction between mcm5U and mcm5Um isoforms is made by the translation machinery, but a small consistent increase in GPX1 translation is associated with the mcm5Um isoform. These results implicate fundamental differences in translation efficiency in playing a role in regulating selenoprotein expression as a function of isoform accumulation.
