Novel Neonatal Umbilical Catheter Protection and Stabilization Device in In vitro Model of Catheterized Human Umbilical Cords: Effect of Material and Venting on Bacterial Colonization.

OBJECTIVE: Umbilical central lines deliver life-saving medications and nutrition for neonates; however, complications associated with umbilical catheters (UCs) occur more frequently than in adults with central lines (i.e., line migration, systemic infection). We have developed a device for neonatal UC protection and stabilization to reduce catheter exposure to bacteria compared with the standard of care: "goal post" tape configuration. This study analyzes the effect of device venting and material on bacterial load of human umbilical cords in vitro. STUDY DESIGN: Catheters were inserted into human umbilical cord segments in vitro, secured with plastic or silicone vented prototype versus tape, and levels of bacterial colonization were compared between groups after 7 days of incubation. RESULTS: Nonvented plastic prototype showed increased bacterial load compared with goal post (p = 0.04). Colonization was comparable between the goal post and all vented plastic prototypes (p ≥ 0.30) and when compared with the vented silicone device (p = 1). CONCLUSION: A novel silicone device does not increase external bacterial colonization compared with the current standard of care for line securement, and may provide a safe, convenient alternative to standard adhesive tape for UC stabilization. Future studies are anticipated to establish safety in vivo, alongside benefits such as migration and infection reduction.

Construction and characterization of metal ion-containing DNA nanowires for synthetic biology and nanotechnology.

DNA is an attractive candidate for integration into nanoelectronics as a biological nanowire due to its linear geometry, definable base sequence, easy, inexpensive and non-toxic replication and self-assembling properties. Recently we discovered that by intercalating Ag+ in polycytosine-mismatch oligonucleotides, the resulting C-Ag+-C duplexes are able to conduct charge efficiently. To map the functionality and biostability of this system, we built and characterized internally-functionalized DNA nanowires through non-canonical, Ag+-mediated base pairing in duplexes containing cytosine-cytosine mismatches. We assessed the thermal and chemical stability of ion-coordinated duplexes in aqueous solutions and conclude that the C-Ag+-C bond forms DNA duplexes with replicable geometry, predictable thermodynamics, and tunable length. We demonstrated continuous ion chain formation in oligonucleotides of 11-50 nucleotides (nt), and enzyme ligation of mixed strands up to six times that length. This construction is feasible without detectable silver nanocluster contaminants. Functional gene parts for the synthesis of DNA- and RNA-based, C-Ag+-C duplexes in a cell-free system have been constructed in an Escherichia coli expression plasmid and added to the open-source BioBrick Registry, paving the way to realizing the promise of inexpensive industrial production. With appropriate design constraints, this conductive variant of DNA demonstrates promise for use in synthetic biological constructs as a dynamic nucleic acid component and contributes molecular electronic functionality to DNA that is not already found in nature. We propose a viable route to fabricating stable DNA nanowires in cell-free and synthetic biological systems for the production of self-assembling nanoelectronic architectures.

Early Percutaneous Heparin-Free Veno-Venous Extra Corporeal Life Support (ECLS) is a Safe and Effective Means of Salvaging Hypoxemic Patients with Complicated Chest Trauma.

BACKGROUND: The objective of this study was to assess the feasibility and safety of heparin-free veno-venous extracorporeal life support (VV ECLS) as a means of salvaging polytrauma patients with life-threatening hypoxemia. METHODS: This is a retrospective observational study on 7 consecutive trauma patients who underwent VV ECLS for severe chest trauma unresponsive to conventional measures. RESULTS: The median time to ECLS was within 10 hrs (IQR 2-53) of mechanical ventilation. Surgical interventions were performed before and during ECLS based on management priorities consistent with advanced trauma life support guidelines. No heparin was used for at least 4 days in this group with activated coagulation time (ACT) approximating 170 seconds by the 3(rd) and 4(th) day. There were no thromboembolic complications. Four patients were successfully discharged and three of these survivors had concomitant traumatic brain injury (TBI) without neurologic sequel. CONCLUSIONS: Early VV ECLS can be used for salvage of patients with traumatic lung injury. Acute trauma care can be continued as needed under heparin-free ECLS without the fear of thromboembolic complications. KEY WORDS: Adult respiratory distress syndrome; Extracorporeal life support; Multiple trauma; Thoracic injury; Traumatic brain injury.

Plasma B-type natriuretic peptide in predicting outcomes of elective coronary artery bypass surgery.

The risks of surgery and its clinical outcome are of great importance for both patients and physicians when choosing coronary artery bypass (CABG) surgery for coronary artery disease. The purpose of the current study was to clarify the relationship between serum B-type natriuretic peptide (BNP) and patient clinical outcome. Seventy-six eligible patients who underwent CABG were enrolled into the prospective study. Venous blood samples were drawn for serum BNP and N-terminal (NT)-proBNP levels measurement on preoperative Day 1, postoperative Day 1, and postoperative Day 7. Clinical end points were: (1) intensive care unit (ICU) stay longer than 4 days postoperatively and/or hospital stay longer than 13 days postoperatively; (2) major complications and poor outcomes. Patients who had prolonged ICU stay and hospitalization had significantly higher postoperative Day 1 BNP and postoperative Day 1 NT-proBNP level (p = 0.02 and 0.005, respectively). Age was significantly older in patients with prolonged ICU stay and hospitalization than those without prolonged ICU stay and hospitalization (p = 0.03). Serum creatinine level was also significantly increased in patients with prolonged ICU stay and hospitalization (p = 0.009). However, age was the only remaining factor that correlated with prolonged ICU stay and hospitalization in the multivariate logistic regression model. These results suggest that research using BNP and NT-proBNP for predicting ICU stay and hospitalization in patients who have undergone CABG must adjust risk factors to present a more appropriate estimation of its clinical outcome.

Visualization of single mRNAs reveals temporal association of proteins with microRNA-regulated mRNA.

Although many proteins are known to function in microRNA (miRNA)-based translational repression, we lack a comprehensive understanding of temporal relationships between the mRNA, miRNA and their constituent proteins. To understand the dynamics of miRNA and protein interactions, we created a synthetic inducible miRNA system in mammalian cells. By visualizing single mRNAs and observing their co-localization with proteins over time, we produced a temporal association map of miRNA-associated factors. Argonaute2, Dcp1a, hedls and Rck co-localize with miRNA-regulated mRNA after 24 h of miRNA induction, and RNAi knockdown of any one of these proteins affected the co-localization of any of the other proteins with miRNA-regulated mRNA, demonstrating that these proteins could interact with each other in a complex. We identified Argonaute2 and hedls as proteins that co-localize and interact with miRNA-regulated mRNA, indicating that processing body components are involved in long-term storage of miRNA-regulated mRNA.

SID-1 is a dsRNA-selective dsRNA-gated channel.

Systemic RNAi in Caenorhabditis elegans requires the widely conserved transmembrane protein SID-1 to transport RNAi silencing signals between cells. When expressed in Drosophila S2 cells, C. elegans SID-1 enables passive dsRNA uptake from the culture medium, suggesting that SID-1 functions as a channel for the transport of double-stranded RNA (dsRNA). Here we show that nucleic acid transport by SID-1 is specific for dsRNA and that addition of dsRNA to SID-1 expressing cells results in changes in membrane conductance, which indicate that SID-1 is a dsRNA gated channel protein. Consistent with passive bidirectional transport, we find that the RNA induced silencing complex (RISC) is required to prevent the export of imported dsRNA and that retention of dsRNA by RISC does not seem to involve processing of retained dsRNA into siRNAs. Finally, we show that mimics of natural molecules that contain both single- and double-stranded dsRNA, such as hairpin RNA and pre-microRNA, can be transported by SID-1. These findings provide insight into the nature of potential endogenous RNA signaling molecules in animals.

The SID-1 double-stranded RNA transporter is not selective for dsRNA length.

The double-stranded RNA (dsRNA) transport protein SID-1 enables systemic RNA interference (RNAi) in Caenorhabditis elegans, whereby silencing initiated by local exposure to dsRNA spreads throughout the animal and to its progeny. Previously, we showed that providing dsRNA in the growth medium of Drosophila S2 cells that express C. elegans SID-1 efficiently triggers RNAi. In these experiments long dsRNA proved to be significantly more effective than short dsRNA in silencing the target gene. Here, we show that equivalent masses of long or short dsRNA accumulate in these cells, indicating that size-dependent silencing is not due to size-selective transport through SID-1. Furthermore, using pulse-chase dsRNA uptake experiments, we show that short dsRNA accumulates more rapidly than long dsRNA. We found that import rates are dependent on dsRNA concentration, consistent with energy-independent, diffusion-limited transport through the SID-1 channel. Comparison of silencing efficiencies between Drosophila S2 cells heterologously expressing SID-1 and primary-cultured C. elegans cells shows similar dsRNA concentration and size dependencies, suggesting that C. elegans regulatory proteins do not measurably enhance or restrict dsRNA transport through SID-1. Finally, we find that coexpressing mutant SID-1 with wild-type SID-1 in S2 cells interferes with SID-1 function, indicating that SID-1 may function as a multimer.

Acute cholecystitis after minimally invasive coronary artery bypass grafting: a report 2 cases.

Acute cholecystitis following coronary artery bypass grafting (CABG), although rare, is a potentially life-threatening consequence of prolonged cardiopulmonary bypass (CPB)procedures. Minimally invasive direct coronary artery bypass (MIDCAB), performed without sternotomy and without CPB, is perhaps the least traumatic type of CABG procedure.Nevertheless, we present 2 cases of acute cholecystitis following MIDCAB, demonstrating that a MIDCAB does not eliminate the risk of gastrointestinal complications. Our experience with these cases points to the benefits of early and aggressive management in the treatment of acute cholecystitis after MIDCAB.

Sequential assembly of photosynthetic units in Rhodobacter sphaeroides as revealed by fast repetition rate analysis of variable bacteriochlorophyll a fluorescence.

The development of functional photosynthetic units in Rhodobacter sphaeroides was followed by near infra-red fast repetition rate (IRFRR) fluorescence measurements that were correlated to absorption spectroscopy, electron microscopy and pigment analyses. To induce the formation of intracytoplasmic membranes (ICM) (greening), cells grown aerobically both in batch culture and in a carbon-limited chemostat were transferred to semiaerobic conditions. In both aerobic cultures, a low level of photosynthetic complexes was observed, which were composed of the reaction center and the LH1 core antenna. Interestingly, in the batch cultures the reaction centers were essentially inactive in forward electron transfer and exhibited low photochemical yields F(V)/F(M), whereas the chemostat culture displayed functional reaction centers with a rather rapid (1-2 ms) electron transfer turnover, as well as a high F(V)/F(M) of approximately 0.8. In both cases, the transfer to semiaerobiosis resulted in rapid induction of bacteriochlorophyll a synthesis that was reflected by both an increase in the number of LH1-reaction center and peripheral LH2 antenna complexes. These studies establish that photosynthetic units are assembled in a sequential manner, where the appearance of the LH1-reaction center cores is followed by the activation of functional electron transfer, and finally by the accumulation of the LH2 complexes.