Safety and Effectiveness of a Novel Facemask for Positive Pressure Ventilation.

BACKGROUND: Manual positive pressure ventilation is an essential skill in a variety of clinical situations. The C&E technique is commonly used with standard facemasks to provide effective ventilation. The Tao mask is a novel design that allows a more ergonomic grip. A seal between the mask and face is made with downward pressure of the palm, centered on the mask, and jaw lift is achieved with 4 fingers centered under the mandible. The purpose of this study was to evaluate the safety and effectiveness of the Tao mask compared to a standard mask before and after the administration of neuromuscular blockade (NMB) using 2 previously established ventilation scales. METHODS: One hundred fifty-two patients >18 years of age who were scheduled for general anesthesia were recruited. All care team members were shown a brief instructional video on the use of the Tao mask. After induction of general anesthesia with a standardized protocol, each patient was ventilated with both the standard (Vital Signs #082510) and Tao masks and effectiveness was measured using the Han and Warters scales. This process was repeated after NMB. The sequence of masks was determined with a random-number generator. RESULTS: Tao mask ventilation scores were significantly better than standard mask scores on both the Han scale and the Warters scale before the administration of NMB (P < .001 for both). Tao mask scores were also significantly better than standard mask scores on the Warters scale after the administration of NMB (P < .001). However, there was no significant difference on the Han scale between the 2 mask types after NMB (P = .180). On the Warters scale, there were significantly fewer patients who were difficult to ventilate with the Tao mask than the standard mask before NMB (18 vs 40; P < .001) and after NMB (8 vs 17; P = .005). No adverse events were reported with either mask. CONCLUSIONS: Our results indicate that the Tao mask demonstrated equivalent safety and superior effectiveness compared to a standard mask. The study design favored the standard mask because all participating practitioners had multiple years of experience with the standard mask and no prior experience with the Tao mask. Since the incidence of inadequate mask ventilation goes up significantly with inexperienced operators, the improved effectiveness of the Tao mask could be even more profound with novice operators.

Comparison of Clinical Outcomes Between General Anesthesiologists and Cardiac Anesthesiologists in the Management of Left Ventricular Assist Device Patients in Noncardiac Surgeries and Procedures.

OBJECTIVE: To describe the authors' experience and comparative results after introducing noncardiac fellowship-trained anesthesiologists to a service previously managed by fellowship-trained cardiac anesthesiologists caring for left ventricular assist device (LVAD) patients undergoing low-risk noncardiac procedures with anesthesia. DESIGN: A retrospective chart review. SETTING: Single-site academic medical center in the United States. INTERVENTIONS: Anesthesia and intraoperative therapy. MEASUREMENTS AND MAIN RESULTS: After initiating a brief training period for the noncardiac fellowship-trained anesthesiologists and blending the noncardiac anesthesiologists into the care of LVAD patients, the electronic medical records of 158 patients with an LVAD who underwent noncardiac procedures were reviewed. The cases were managed by either cardiac-trained anesthesiologists or noncardiac-trained anesthesiologists. Their performance was evaluated on the basis of technique and outcome. The parameters for technique were the use of intubation and mechanical ventilation, use of vasoactive medications, type of vasoactive medications administered, use of invasive monitoring, and type and amount of intravenous fluid administration. The outcomes examined included occurrence of intraoperative mean blood pressure <55 mmHg, intraoperative cardiac arrest, intraoperative device malfunction, thromboembolic complications, inability to complete procedure due to intraoperative nonsurgical complication, unplanned postoperative intensive care unit admission, unplanned hospital readmission within 30 days, and the 30-day postoperative mortality rate. This analysis demonstrated no statistically significant associations between the type of anesthesiologist and the use of fluid, amount of fluid given, use of vasopressors, or use of invasive monitoring devices. There were no significant differences in specific patient outcomes by anesthesia provider type. CONCLUSIONS: Patients with LVADs can be managed by either a noncardiac or a cardiac fellowship-trained anesthesiologist with similar technique and outcome during low-risk noncardiac procedures and surgeries.

Improved specificity of gene silencing by siRNAs containing unlocked nucleobase analogs.

siRNAs confer sequence specific and robust silencing of mRNA. By virtue of these properties, siRNAs have become therapeutic candidates for disease intervention. However, their use as therapeutic agents can be hampered by unintended off-target effects by either or both strands of the siRNA duplex. We report here that unlocked nucleobase analogs (UNAs) confer desirable properties to siRNAs. Addition of a single UNA at the 5'-terminus of the passenger strand blocks participation of the passenger strand in RISC-mediated target down-regulation with a concomitant increase in guide strand activity. Placement of a UNA in the seed region of the guide strand prevents miRNA-like off-target silencing without compromising siRNA activity. Most significantly, combined substitution of UNA at the 3'-termini of both strands, the addition of a UNA at the 5'-terminus of the passenger strand, and a single UNA in the seed region of the guide strand, reduced the global off-target events by more than 10-fold compared to unmodified siRNA. The reduction in off-target events was specific to UNA placement in the siRNA, with no apparent new off-target events. Taken together, these results indicate that when strategically placed, UNA substitutions have important implications for the design of safe and effective siRNA-based therapeutics.

An amino acid-based amphoteric liposomal delivery system for systemic administration of siRNA.

We demonstrate a systematic and rational approach to create a library of natural and modified, dialkylated amino acids based upon arginine for development of an efficient small interfering RNA (siRNA) delivery system. These amino acids, designated DiLA2 compounds, in conjunction with other components, demonstrate unique properties for assembly into monodisperse, 100-nm small liposomal particles containing siRNA. We show that DiLA2-based liposomes undergo a pH-dependent phase transition to an inverted hexagonal phase facilitating efficient siRNA release from endosomes to the cytosol. Using an arginine-based DiLA2, cationic liposomes were prepared that provide high in vivo siRNA delivery efficiency and are well-tolerated in both cell and animal models. DiLA2-based liposomes demonstrate a linear dose-response with an ED50 of 0.1 mg/kg against liver-specific target genes in BALB/c mice.

RNAi-based therapeutics targeting survivin and PLK1 for treatment of bladder cancer.

Harnessing RNA interference (RNAi) to silence aberrant gene expression is an emerging approach in cancer therapy. Selective inhibition of an overexpressed gene via RNAi requires a highly efficacious, target-specific short interfering RNA (siRNA) and a safe and efficient delivery system. We have developed siRNA constructs (UsiRNA) that contain unlocked nucleobase analogs (UNA) targeting survivin and polo-like kinase-1 (PLK1) genes. UsiRNAs were encapsulated into dialkylated amino acid-based liposomes (DiLA(2)) containing a nor-arginine head group, cholesteryl hemisuccinate (CHEMS), cholesterol and 1, 2-dimyristoyl-phosphatidylethanolamine-polyethyleneglycol 2000 (DMPE-PEG2000). In an orthotopic bladder cancer mouse model, intravesical treatment with survivin or PLK1 UsiRNA in DiLA(2) liposomes at 1.0 and 0.5 mg/kg resulted in 90% and 70% inhibition of survivin or PLK1 mRNA, respectively. This correlated with a dose-dependent decrease in tumor volumes which was sustained over a 3-week period. Silencing of survivin and PLK1 mRNA was confirmed to be RNA-induced silencing complex mediated as specific cleavage products were detected in bladder tumors over the duration of the study. This report suggests that intravesical instillation of survivin or PLK1 UsiRNA can serve as a potential therapeutic modality for treatment of bladder cancer.

Hypothermic machine preservation attenuates ischemia/reperfusion markers after liver transplantation: preliminary results.

BACKGROUND: Hypothermic machine perfusion (HMP) has shown significant benefits in renal transplantation but is still in its infancy in liver transplantation. Potential benefits include diminished preservation injury and improved early graft function. METHODS: We analyzed liver tissue and effluent collected during our Phase 1 trial of liver HMP. Liver allografts underwent HMP for 4-7 h using dual centrifugal perfusion with Vasosol solution at 4-8°C were transplanted and compared with cold stored (CS) transplant controls. Histology, reverse transcription-polymerase chain reaction (RT-PCR), and immunohistochemistry on liver biopsies compared histology and expression of early proinflammatory cytokines, IL-8 and TNF-α, and intracellular adhesion molecule-1 (ICAM-1). Gel electrophoresis was used to evaluate effluent protein content representing residual metabolism. RESULTS: We saw no differences between HMP and CS in early histologic findings after reperfusion. RT-PCR of reperfusion biopsy samples in the CS group showed high expression of proinflammatory cytokines and ICAM-1. This up-regulation was significantly attenuated by HMP (ICAM-1; P = 0.0152) (IL-8; P = 0.0014) (TNF-α; P = 0.0284). This was confirmed with immunohistochemistry. Albumin was identified in the perfusate throughout HMP. CONCLUSIONS: HMP significantly reduced proinflammatory cytokine expression compared with CS controls. Further studies of human liver HMP with detailed molecular investigations are now warranted to elucidate benefits of HMP in liver transplantation.

The role of membrane microdomains in transmembrane signaling through the epithelial glycoprotein Gp140/CDCP1.

Cell adhesion to the extracellular matrix (ECM) via integrin adhesion receptors initiates signaling cascades leading to changes in cell behavior. While integrin clustering is necessary to initiate cell attachment to the matrix, additional membrane components are necessary to mediate the transmembrane signals and the cell adhesion response that alter downstream cell behavior. Many of these signaling components reside in glycosphingolipid-rich and cholesterol-rich membrane domains such as Tetraspanin Enriched Microdomains (TEMs)/Glycosynapse 3 and Detergent-Resistant Microdomains (DRMs), also known as lipid rafts. In the following article, we will review examples of how components in these membrane microdomains modulate integrin adhesion after initial attachment to the ECM. Additionally, we will present data on a novel adhesion-responsive transmembrane glycoprotein Gp140/CUB Domain Containing Protein 1, which clusters in epithelial cell-cell contacts. Gp140 can then be phosphorylated by Src Family Kinases at tyrosine 734 in response to outside-in signals-possibly through interactions involving the extracellular CUB domains. Data presented here suggests that outside-in signals through Gp140 in cell-cell contacts assemble membrane clusters that associate with membrane microdomains to recruit and activate SFKs. Active SFKs then mediate phosphorylation of Gp140, SFK and PKCdelta with Gp140 acting as a transmembrane scaffold for these kinases. We propose that the clustering of Gp140 and signaling components in membrane microdomains in cell-cell contacts contributes to changes in cell behavior.

Advantages of the New Tao Mask for Bag Mask Ventilation: a randomized crossover trial.

BACKGROUND AND AIMS: Manual bag mask ventilation is a life saving skill. An investigation was made to compare two different facemasks used in bag mask ventilation, the standard and the novel Tao face mask, and evaluate the ability of novices to achieve adequate tidal volume. METHODS: The study design was a crossover trial, which randomized forty medical students with no previous airway experience to learn bag mask ventilation with the standard mask and the Tao face mask. Primary outcome measures were mean and median tidal volume per mask, and secondary measures were hand area, age, gender, and order of mask usage. RESULTS: Medical students who used the Tao mask first achieved significantly more tidal volume than those who used the standard mask first (p = 0.002). However, when comparing face masks that were used second, the tidal volume did not differ significantly between the two masks (p = 1.000). Greater tidal volume was achieved on the second attempt relative to the first attempt with each mask. There was significantly more tidal volume achieved with greater hand size with the standard mask, whether it was used first or second (p < 0.001 and p = 0.012 respectively). Greater hand size was associated with greater tidal volume in the Tao mask also, but only when used first (p < 0.001). When first attempting bag mask ventilation, inexperienced students achieved greater tidal volume with the Tao Mask. The results also suggest that hand size matters less when using the Tao Mask. CONCLUSION: When first attempting bag mask ventilation inexperienced students achieved greater tidal volume with the Tao Mask. The results also suggest that hand size matters less when using the Tao mask.

Adhesion or plasmin regulates tyrosine phosphorylation of a novel membrane glycoprotein p80/gp140/CUB domain-containing protein 1 in epithelia.

Suspension of cultured human foreskin keratinocytes (HKs) with trypsin phosphorylates tyrosine residues on an 80-kDa membrane glycoprotein, p80 (Xia, Y., Gil, S. G., and Carter, W. G. (1996) J. Cell Biol. 132, 727-740). Readhesion dephosphorylates p80. Sequencing of a p80 cDNA established identity to CUB domain-containing protein 1 (CDCP1), a gene elevated in carcinomas. CDCP1/p80 cDNA encodes three extracellular CUB domains, a transmembrane domain, and two putative cytoplasmic Tyr phosphorylation sites. Treatment of adherent HKs with suramin, a heparin analogue, or inhibitors of phosphotyrosine phosphatases (PTPs; vanadate or calpeptin) increases phosphorylation of p80 and a novel 140-kDa membrane glycoprotein, gp140. Phosphorylated gp140 was identified as a trypsin-sensitive precursor to p80. Identity was confirmed by digestion and phosphorylation studies with recombinant gp140-GFP. Plasmin, a serum protease, also converts gp140 to p80, providing biological significance to the cleavage in wounds. Phosphorylation of gp140 and p80 are mediated by Src family kinases at multiple Tyr residues including Tyr(734). Dephosphorylation is mediated by PTP(s). Conversion of gp140 to p80 prolongs phosphorylation of p80 in response to suramin and changes in adhesion. This distinguishes gp140 and p80 and explains the relative abundance of phosphorylated p80 in trypsinized HKs. We conclude that phosphorylation of gp140 is dynamic and balanced by Src family kinase and PTPs yielding low equilibrium phosphorylation. We suggest that the balance is altered by conversion of gp140 to p80 and by adhesion, providing a novel transmembrane phosphorylation signal in epithelial wounds.

Globular domains 4/5 of the laminin alpha3 chain mediate deposition of precursor laminin 5.

In epidermal wounds, precursor laminin 5 (alpha3beta3gamma2) is deposited in the provisional basement membrane (PBM) before other BM components. Precursor laminin 5 contains G4/5 globular domains at the carboxyl terminus of the alpha3 chain. Here, the function of G4/5 was evaluated in deposition of laminin 5. Soluble laminin 5, secreted by keratinocytes in culture, is cleaved by an endogenous protease releasing G4/5. Thrombin, a serum protease, cleaves G4/5 indistinguishably from endogenous protease. Soluble human precursor laminin 5, but not cleaved laminin 5, was bound and deposited by mouse keratinocytes null for mouse alpha3 chain (alpha3-/- MKs). The deposition rescued adhesion and spreading and survival. In a model for PBM assembly, precursor laminin 5 was deposited along fibronectin fibrils at the junction between co-cultures of keratinocytes and fibroblasts. In both models, the deposition of precursor laminin 5 was inhibited by removal of G4/5 with thrombin. To confirm that G4/5 participates in deposition, the human LAMA3A gene was modified to produce alpha3 chains either without or with G4/5 that cannot be cleaved. Both precleaved and noncleavable alpha3 isoforms were expressed in alpha3-/- MKs, where they deposited sufficiently to rescue adhesion via integrins alpha3beta1 and alpha6beta4. Despite this similarity, noncleavable laminin 5 was at least threefold more efficiently deposited than precleaved isoform. We conclude that the G4/5 domain in the alpha3 chain facilitates deposition of precursor laminin 5 into the PBM in epidermal wounds.