bluuebunny/crossref_metadata_2025 huggingface dataset:
SOCS3 drives proteasomal degradation of indoleamine 2,3-dioxygenase (IDO) and antagonizes IDO-dependent tolerogenesis
Authors: Orabona Ciriana , Pallotta Maria T. , Volpi Claudia , Fallarino Francesca , Vacca Carmine , Bianchi Roberta , Belladonna Maria L. , Fioretti Maria C. , Grohmann Ursula , Puccetti Paolo
Published: December 2008

Despite their common ability to activate intracellular signaling through CD80/CD86 molecules, cytotoxic T lymphocyte antigen 4 (CTLA-4)-Ig and CD28-Ig bias the downstream response in opposite directions, the latter promoting immunity, and CTLA-4-Ig tolerance, in dendritic cells (DCs) with opposite but flexible programs of antigen presentation. Nevertheless, in the absence of suppressor of cytokine signaling 3 (SOCS3), CD28-Ig—and the associated, dominant IL-6 response—become immunosuppressive and mimic the effect of CTLA-4-Ig, including a high functional expression of the tolerogenic enzyme indoleamine 2,3-dioxygenase (IDO). Here we show that forced SOCS3 expression antagonized CTLA-4-Ig activity in a proteasome-dependent fashion. Unrecognized by previous studies, IDO appeared to possess two tyrosine residues within two distinct putative immunoreceptor tyrosine-based inhibitory motifs, VPY115CEL and LLY253EGV. We found that SOCS3—known to interact with phosphotyrosine-containing peptides and be selectively induced by CD28-Ig/IL-6—would bind IDO and target the IDO/SOCS3 complex for ubiquitination and subsequent proteasomal degradation. This event accounted for the ability of CD28-Ig and IL-6 to convert otherwise tolerogenic, IDO-competent DCs into immunogenic cells. Thus onset of immunity in response to antigen within an early inflammatory context requires that IDO be degraded in tolerogenic DCs. In addition to identifying SOCS3 as a candidate signature for mouse DC subsets programmed to direct immunity, this study demonstrates that IDO undergoes regulatory proteolysis in response to immunogenic stimuli.
Multilayer three-dimensional super resolution imaging of thick biological samples
Authors: Vaziri Alipasha , Tang Jianyong , Shroff Hari , Shank Charles V.
Published: December 2008

Recent advances in optical microscopy have enabled biological imaging beyond the diffraction limit at nanometer resolution. A general feature of most of the techniques based on photoactivated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM) has been the use of thin biological samples in combination with total internal reflection, thus limiting the imaging depth to a fraction of an optical wavelength. However, to study whole cells or organelles that are typically up to 15 μm deep into the cell, the extension of these methods to a three-dimensional (3D) super resolution technique is required. Here, we report an advance in optical microscopy that enables imaging of protein distributions in cells with a lateral localization precision better than 50 nm at multiple imaging planes deep in biological samples. The approach is based on combining the lateral super resolution provided by PALM with two-photon temporal focusing that provides optical sectioning. We have generated super-resolution images over an axial range of ≈10 μm in both mitochondrially labeled fixed cells, and in the membranes of living S2
Drosophila
cells.
The co-chaperone BAG3 regulates Herpes Simplex Virus replication
Authors: Kyratsous Christos A. , Silverstein Saul J.
Published: December 2008

Viruses as obligate intracellular parasites use host cell proteins to ensure efficient replication and spread. Cellular proteins are required for several stages of a virus life cycle. Here, we identify BAG3, a co-chaperone, as a regulator of herpes virus immediate early gene expression. We report that a herpes simplex virus lacking the gene encoding a potent transcriptional activator, ICP0, is compromised for replication in cells silenced for BAG3 in a multiplicity of infection-dependent manner. We also show a requirement for BAG3 to augment virus gene expression and demonstrate that the co-chaperone acts independently of promyelocytic leukemia to increase herpes simplex virus replication.
Genome-wide analysis of cancer/testis gene expression
Authors: Hofmann Oliver , Caballero Otavia L. , Stevenson Brian J. , Chen Yao-Tseng , Cohen Tzeela , Chua Ramon , Maher Christopher A. , Panji Sumir , Schaefer Ulf , Kruger Adele , Lehvaslaiho Minna , Carninci Piero , Hayashizaki Yoshihide , Jongeneel C. Victor , Simpson Andrew J. G. , Old Lloyd J. , Hide Winston
Published: December 2008

Cancer/Testis (CT) genes, normally expressed in germ line cells but also activated in a wide range of cancer types, often encode antigens that are immunogenic in cancer patients, and present potential for use as biomarkers and targets for immunotherapy. Using multiple in silico gene expression analysis technologies, including twice the number of expressed sequence tags used in previous studies, we have performed a comprehensive genome-wide survey of expression for a set of 153 previously described CT genes in normal and cancer expression libraries. We find that although they are generally highly expressed in testis, these genes exhibit heterogeneous gene expression profiles, allowing their classification into testis-restricted (
39
), testis/brain-restricted (
14
), and a testis-selective (85) group of genes that show additional expression in somatic tissues. The chromosomal distribution of these genes confirmed the previously observed dominance of X chromosome location, with CT-X genes being significantly more testis-restricted than non-X CT. Applying this core classification in a genome-wide survey we identified >30 CT candidate genes; 3 of them, PEPP-2, OTOA, and AKAP4, were confirmed as testis-restricted or testis-selective using RT-PCR, with variable expression frequencies observed in a panel of cancer cell lines. Our classification provides an objective ranking for potential CT genes, which is useful in guiding further identification and characterization of these potentially important diagnostic and therapeutic targets.
DEAD-box proteins can completely separate an RNA duplex using a single ATP
Authors: Chen Yingfeng , Potratz Jeffrey P. , Tijerina Pilar , Del Campo Mark , Lambowitz Alan M. , Russell Rick
Published: December 2008

DEAD-box proteins are ubiquitous in RNA metabolism and use ATP to mediate RNA conformational changes. These proteins have been suggested to use a fundamentally different mechanism from the related DNA and RNA helicases, generating local strand separation while remaining tethered through additional interactions with structured RNAs and RNA-protein (RNP) complexes. Here, we provide a critical test of this model by measuring the number of ATP molecules hydrolyzed by DEAD-box proteins as they separate short RNA helices characteristic of structured RNAs (6–11 bp). We show that the DEAD-box protein CYT-19 can achieve complete strand separation using a single ATP, and that 2 related proteins, Mss116p and Ded1p, display similar behavior. Under some conditions, considerably <1 ATP is hydrolyzed per separation event, even though strand separation is strongly dependent on ATP and is not supported by the nucleotide analog AMP-PNP. Thus, ATP strongly enhances strand separation activity even without being hydrolyzed, most likely by eliciting or stabilizing a protein conformation that promotes strand separation, and AMP-PNP does not mimic ATP in this regard. Together, our results show that DEAD-box proteins can disrupt short duplexes by using a single cycle of ATP-dependent conformational changes, strongly supporting and extending models in which DEAD-box proteins perform local rearrangements while remaining tethered to their target RNAs or RNP complexes. This mechanism may underlie the functions of DEAD-box proteins by allowing them to generate local rearrangements without disrupting the global structures of their targets.
E3 ligase activity of BRCA1 is not essential for mammalian cell viability or homology-directed repair of double-strand DNA breaks
Authors: Reid Latarsha J. , Shakya Reena , Modi Ami P. , Lokshin Maria , Cheng Jiin-Tsuey , Jasin Maria , Baer Richard , Ludwig Thomas
Published: December 2008

Hereditary cases of breast and ovarian cancer are often attributed to germ-line mutations of the BRCA1 tumor suppressor gene. Although BRCA1 is involved in diverse cellular processes, its role in the maintenance of genomic integrity may be a key component of its tumor suppression activity. The protein encoded by BRCA1 interacts in vivo with the related BARD1 protein to form a heterodimeric complex that acts as a ubiquitin E3 ligase. Because the enzymatic activity of the BRCA1/BARD1 heterodimer is conserved over a broad phylogenetic range, it is thought to be critical for the central functions of BRCA1. To test this hypothesis, we have generated isogenic clones of embryonic stem cells that do or do not express an enzymatically proficient Brca1 polypeptide. Surprisingly, cells lacking the ubiquitin ligase activity of BRCA1 are viable and do not accumulate spontaneous cytogenetic rearrangements. Gene targeting efficiencies are modestly reduced in these cells, and chromosomal rearrangements arise at elevated rates in response to genotoxic stress. Nonetheless, cells lacking Brca1 enzymatic activity are not hypersensitive to the DNA cross-linking agent mitomycin C. They also form Rad51 focus in response to ionizing radiation and repair chromosome breaks by homologous recombination at wild-type levels. These results indicate that key aspects of BRCA1 function in genome maintenance, including its role in homology-directed repair of double-strand DNA breaks, do not depend on the E3 ligase activity of BRCA1.
Abnormal bleeding associated with preeclampsia: A population study of 315,085 pregnancies
Authors: ESKILD ANNE , VATTEN LARS J.
Published: December 2008

Objective. To study the association of preeclampsia with abnormal bleeding in the first trimester and after delivery. Design. Register‐based population study. Setting. The Medical Birth Registry of Norway. Population. A total of 315,085 women in Norway with singleton deliveries after 21 weeks of gestation (1999–2004). Methods. We compared frequencies of vaginal bleeding in the first trimester between women who subsequently developed preeclampsia and women without preeclampsia development, and made similar comparisons for postpartum bleeding. Main outcome measures. Proportion of women with bleeding. Results. In the first trimester, vaginal bleeding occurred in 1.6% (215/13,166) of subsequent preeclampsia cases, compared to 2.0% (6,112/301,919) of normotensives (p<0.01). After delivery, excess postpartum bleeding (>1,500 mL) occurred in 3.0% (399/13,166) of preeclampsia cases and in 1.4% (4,223/301,919) of normotensives (p<0.01). Moderate bleeding postpartum (>500 mL) was also more common in preeclampsia cases (22.9% versus 13.9%, p<0.01). Similar patterns were present in first time mothers and in women with more than one birth, and the patterns did not vary according to type of delivery (cesarean section or not). Conclusions. These results suggest that factors associated with preeclampsia are inversely related to vaginal bleeding early in pregnancy, but positively associated with excess bleeding after delivery.
Myomectomy during cesarean section
Authors: LI HUI , DU JUAN , JIN LIANGYI , SHI ZHAN , LIU MINGYING
Published: December 2008

Objective. To evaluate the safety and effectiveness of myomectomy during cesarean section (CS). Design. Retrospective case‐control study. Setting. Tertiary referral university hospital. Population and methods. A study group of 1,242 pregnant women with fibromyomas who underwent myomectomy during CS and three control groups of 200 matched pregnant women without fibromyomas who underwent CS deliveries (Group A), 145 patients with fibromyomas who underwent CS deliveries without removal of fibromyomas (Group B) and 51 patients with fibromyomas who had a hysterectomy during CS (Group C). Main outcome measures. The difference between pre‐ and postoperative hemoglobin levels, the incidence of hemorrhage, blood transfusion, postoperative fever, duration of operation and length of hospital stay. Results. No difference was found in the median parity or mean gestational age, but maternal age was higher and the gestational age lower in Group C than the study group. The median number and diameter of fibromyomas in Group B were lower than in the study group. Compared to the study group, Group B women had more single fibromyomas, while those in Group C had more multiple fibromyomas. Group B had more uterine cornual fibromyomas than the study group. There were no differences in the mean hemoglobin change, the incidence of postoperative fever and the length of hospital stay among groups. Conclusion. Myomectomy during CS was a safe and an effective procedure.
Efficacy of Combination of N-acetylcysteine, Gentamicin, and Amphotericin B for Prevention of Microbial Colonization of Ventricular Assist Devices
Authors: Hernandez Maria D. , Mansouri Mohammad D. , Aslam Saima , Zeluff Barry , Darouiche Rabih O.
Published: December 2008

We assessed the in vitro antimicrobial activity and the in vivo efficacy of dipping ventricular assist devices in a combination of N-acetylcysteine, gentamicin, and amphotericin B (NAC/G/A). Ventricular assist devices dipped in NAC/G/A exhibited broad-spectrum antimicrobial activity in vitro and were less likely than undipped devices to become colonized with Staphylococcus aureus in a rabbit model.
Lost in Translation? Reliability of Assessing Inpatient Antimicrobial Appropriateness With Use of Computerized Case Vignettes
Authors: Schwartz David N. , Wu Ulysses S. , Lyles Rosie D. , Xiang Yingxu , Kieszkowski Piotr , Hota Bala , Weinstein Robert A.
Published: December 2008

Objective.

To describe and measure reliability of a computer-assisted method of case vignette assembly and expert review to assess the appropriateness of antimicrobial therapy for hospitalized adults.

Design.

Feasibility and reliability analysis of computer-assisted tool used to compare the effects of antimicrobial stewardship interventions.

Setting.

Public teaching hospital.

Patients.

Randomly selected adult antimicrobial recipients admitted to inpatient medicine services.

Methods.

Clinical data abstracted from 504 paper medical records were merged with computerized laboratory and pharmacy data to assemble case vignettes that underwent expert review for appropriateness. We performed 3 validations, as follows: data for 35 vignettes abstracted independently by 2 research assistants were assessed for interrater agreement, expert review of 24 vignettes was compared with review of the corresponding paper medical records, and interrater reliability of antimicrobial appropriateness assessments by 2 experts was determined for 70 case vignettes.

Results.

Vignette assembly and expert review each required 10–12 minutes per case. Potentially important discrepancies occurred in 0%–32% of clinical findings abstracted independently by 2 research assistants. Expert review of 24 vignettes and the corresponding full paper medical records yielded fair agreement (kappa, 0.30). The 2 experts identified inappropriate initial antimicrobial therapy in 67% and 61% of case vignettes reviewed independently; interrater agreement was improved after sequential case discussion and stringent application of appropriateness criteria (kappa, 0.72).

Conclusions.

Our case vignette assembly and expert review method is efficient, but improvements in both technical and human performance are needed to be able to yield valid estimates of the prevalence of inappropriate antimicrobial use. Assessments of antimicrobial appropriateness require validation.
Preoperative Use of Statins Is Associated with Reduced Early Delirium Rates after Cardiac Surgery
Authors: Katznelson Rita , Djaiani George N. , Borger Michael A. , Friedman Zeev , Abbey Susan E. , Fedorko Ludwik , Karski Jacek , Mitsakakis Nicholas , Carroll Jo , Beattie W Scott
Published: December 2008

Background

Delirium is an acute deterioration of brain function characterized by fluctuating consciousness and an inability to maintain attention. Use of statins has been shown to decrease morbidity and mortality after major surgical procedures. The objective of this study was to determine an association between preoperative administration of statins and postoperative delirium in a large prospective cohort of patients undergoing cardiac surgery with cardiopulmonary bypass.

Methods

After Institutional Review Board approval, data were prospectively collected on consecutive patients undergoing cardiac surgery with cardiopulmonary bypass from April 2005 to June 2006 in an academic hospital. All patients were screened for delirium during their hospitalization using the Confusion Assessment Method in the intensive care unit. Multivariable logistic regression analysis was used to identify independent perioperative predictors of delirium after cardiac surgery. Statins were tested for a potential protective effect.

Results

Of the 1,059 patients analyzed, 122 patients (11.5%) had delirium at any time during their cardiovascular intensive care unit stay. Administration of statins had a protective effect, reducing the odds of delirium by 46%. Independent predictors of postoperative delirium included older age, preoperative depression, preoperative renal dysfunction, complex cardiac surgery, perioperative intraaortic balloon pump support, and massive blood transfusion. The model was reliable (Hosmer-Lemeshow test, P = 0.3) and discriminative (area under receiver operating characteristic curve = 0.77).

Conclusions

Preoperative administration of statins is associated with the reduced risk of postoperative delirium after cardiac surgery with cardiopulmonary bypass.
Respiratory and Sleep Effects of Remifentanil in Volunteers with Moderate Obstructive Sleep Apnea
Authors: Bernards Christopher M. , Knowlton Susan L. , Schmidt Douglas F. , DePaso William J. , Lee Matthias K. , McDonald Susan B. , Bains Oneil S.
Published: December 2008

Background

There is concern that opioid-based analgesia will worsen sleep-related respiratory insufficiency in patients with obstructive sleep apnea (OSA), resulting in serious morbidity or mortality. However, there are no studies that directly address the merit of this concern. Consequently, the authors designed this study as the first prospective, double-blind, placebo-controlled investigation of opioid pharmacology in patients with documented OSA.

Methods

Patients (n = 19) with moderate OSA documented by polysomnography (sleep study) were randomized to undergo an additional sleep study while receiving either a saline infusion or a remifentanil infusion (0.075 microg x kg x h). Sleep stages, apneas, hypopneas, and arterial hemoglobin oxygen saturation were continually recorded during saline or remifentanil infusion, and were compared with values obtained during the patients' earlier sleep study.

Results

Saline infusion had no effect on sleep or respiratory variables. In contrast, remifentanil increased Stage 1 sleep, markedly decreased rapid eye movement sleep, increased arousals from sleep, and decreased sleep efficiency. Remifentanil actually decreased the number of obstructive apneas, but markedly increased the number of central apneas. Arterial hemoglobin oxygen saturation was also significantly lower in OSA patients receiving remifentanil.

Conclusions

The decrease in obstructive apneas likely resulted from the marked decrease in rapid eye movement sleep caused by remifentanil. Despite fewer obstructions, OSA was worse during remifentanil infusion because of a marked increase in the number of central apneas. These data suggest that caution is warranted when administering opioids to subjects with moderate OSA, but that the primary risk may be central apnea, not obstructive apnea.
Effects of Propofol on Cyclic Strain-induced Endothelin-1 Expression in Human Umbilical Vein Endothelial Cells
Authors: Cheng Tzu-Hurng , Chen Jin-Jer , Chen Cheng-Hsien , Wong Kar-Lok
Published: December 2008

Background

Propofol is one of the most popular intravenous induction agents of general anesthesia. Experimental results revealed that propofol exerted hypotensive and antioxidative effects. However, the intracellular mechanism of propofol remains to be delineated. The aims of this study were to test the hypothesis that propofol may alter strain-induced endothelin-1 (ET-1) secretion and nitric oxide production, and to identify the putative underlying signaling pathways in human umbilical vein endothelial cells.

Methods

Cultured human umbilical vein endothelial cells were exposed to cyclic strain in the presence of propofol, and ET-1 expression was examined by Northern blotting and enzyme-linked immunosorbent assay kit. Activation of extracellular signal-regulated protein kinase, endothelial nitric oxide synthase, and protein kinase B were assessed by Western blot analysis.

Results

The authors show that propofol inhibits strain-induced ET-1 expression, strain-increased reactive oxygen species formation, and extracellular signal-regulated protein kinase phosphorylation. On the contrary, nitric oxide production, endothelial nitric oxide synthase activity, and protein kinase B phosphorylation were enhanced by propofol treatment. Furthermore, in the presence of PTIO, a nitric oxide scavenger, and KT5823, a specific inhibitor of cyclic guanosine monophosphate-dependent protein kinase, the inhibitory effect of propofol on strain-induced extracellular signal-regulated protein kinase phosphorylation and ET-1 release was reversed.

Conclusions

The authors demonstrate for the first time that propofol inhibits strain-induced ET-1 secretion and enhances strain-increased nitric oxide production in human umbilical vein endothelial cells. Thus, this study delivers important new insight into the molecular pathways that may contribute to the proposed hypotensive effects of propofol in the cardiovascular system.
Differential Effects of Propofol and Sevoflurane on Ischemia-induced Ventricular Arrhythmias and Phosphorylated Connexin 43 Protein in Rats
Authors: Hirata Naoyuki , Kanaya Noriaki , Kamada Noriko , Kimura Saori , Namiki Akiyoshi
Published: December 2008

Background

The effects of anesthetics on ischemia-induced ventricular arrhythmias remain poorly studied. This study investigated the effects of propofol and sevoflurane on the survival rate and morbidity as a result of ventricular arrhythmias, and defined a possible mechanism for the arrhythmogenic properties of anesthetics during acute myocardial ischemia.

Methods

Under anesthesia with intraperitoneal sodium pentobarbital, Sprague-Dawley rats underwent 30 min of left anterior descending coronary artery ligation. The rats were divided into a low-dose propofol (Prop-LD) group (39 mg X kg(-1) X hr(-1), n = 18), a high-dose propofol group (78 mg x kg(-1) x hr(-1), n = 18), a sevoflurane group (2.5%, n = 18) and a control group (n = 18). The survival rate and morbidity as a result of ventricular arrhythmias were determined, and the amount of phosphorylated connexin 43 protein was measured 30 min after coronary artery ligation.

Results

The survival rate was 83% (15 of 18), 94% (17 of 18), 89% (16 of 18), and 67% (12 of 18, P = 0.038 vs. Prop-LD) in the control, Prop-LD, high-dose propofol, and sevoflurane groups, respectively. Sustained ventricular tachycardia was observed in 83% (15 of 18), 39% (7 of 18, P = 0.011 vs. control), 50% (9 of 18, P = 0.039 vs. control) and 94% (17 of 18, P < 0.01 vs. Prop-LD) in the control, Prop-LD, high-dose propofol, and sevoflurane groups, respectively. Immunoblotting showed a marked reduction in the amount of phosphorylated connexin 43 in the control and sevoflurane groups, as compared with the Prop-LD and high-dose propofol groups (P < 0.05).

Conclusion

The authors' results suggest that propofol preserves connexin 43 phosphorylation during acute myocardial ischemia, as compared with sevoflurane, and this might protect the heart from serious ventricular arrhythmias during acute coronary occlusion.
Manual In-line Stabilization Increases Pressures Applied by the Laryngoscope Blade during Direct Laryngoscopy and Orotracheal Intubation
Authors: Santoni Brandon G. , Hindman Bradley J. , Puttlitz Christian M. , Weeks Julie B. , Johnson Nathaniel , Maktabi Mazen A. , Todd Michael M.
Published: December 2008

Background

Manual in-line stabilization (MILS) is recommended during direct laryngoscopy and intubation in patients with known or suspected cervical spine instability. Because MILS impairs glottic visualization, the authors hypothesized that anesthesiologists would apply greater pressure during intubations with MILS than without.

Methods

Nine anesthetized and pharmacologically paralyzed patients underwent two sequential laryngoscopies and intubations, one with MILS and one without, in random order. A transducer array along a Macintosh 3 laryngoscope blade continuously measured applied pressures, and glottic view was characterized.

Results

With MILS, glottic visualization was worse in six patients, and intubation failure occurred in two of these six patients. Maximum laryngoscope pressure at best glottic view was greater with MILS than without (717 +/- 339 mmHg vs. 363 +/- 121 mmHg, respectively; n = 8; P = 0.023). Other measures of pressure application also indicated comparable increases with MILS.

Conclusion

Pressures applied to airway tissues by the laryngoscope blade are secondarily transmitted to the cervical spine and result in cranio-cervical motion. In the presence of cervical instability, impaired glottic visualization and secondary increases in pressure application with MILS have the potential to increase pathologic cranio-cervical motion.
Rigid Laryngoscope-assisted Insertion of Transesophageal Echocardiography Probe Reduces Oropharyngeal Mucosal Injury in Anesthetized Patients
Authors: Na SungWon , Kim Chang Seok , Kim Ji Young , Cho Jin Seon , Kim Ki Jun
Published: December 2008

Background

Intraoperative transesophageal echocardiography has become a routine part of monitoring in patients with cardiac disease. However, insertion of a transesophageal echocardiography probe can be associated with oropharyngeal, esophageal, and gastric injuries. The purpose of this study was to determine whether insertion of a transesophageal echocardiography probe under direct laryngoscopic visualization can reduce the incidence of oropharyngeal mucosal injury.

Methods

Eighty patients undergoing surgery with general anesthesia were randomly allocated to either the conventional group, in which the probe was inserted blindly, or the laryngoscope group, in which a rigid laryngoscope was used to visualize the passage of the probe. The incidence of oropharyngeal mucosal injury, the number of insertion attempts, and odynophagia were assessed.

Results

There was no significant difference in demographic and hemodynamic parameters between the 2 groups. The incidence of oropharyngeal mucosal injury was higher in the conventional group than in the laryngoscope group (55% vs. 5%, P < 0.05). The incidence of odynophagia was higher in the conventional group than in the laryngoscope group (32.5% vs. 2.5%, P < 0.05). The number of insertion attempts was also higher in the conventional group than in the laryngoscope group.

Conclusion

Rigid laryngoscope-assisted insertion of the transesophageal echocardiography probe reduces the incidence of oropharyngeal mucosal injury, odynophagia, and the number of insertion attempts.
Laryngoscopy via Macintosh Blade versus GlideScope
Authors: Nouruzi-Sedeh Parichehr , Schumann Mark , Groeben Harald
Published: December 2008

Background

Tracheal intubation is the preferred technique to secure the airway and apply mechanical ventilation. However, when performed by untrained medical personnel, tracheal intubation via direct laryngoscopy has a high rate of failure. The GlideScope (Verathon Medical Europe, Ijsselstein, Netherlands) technique improves the success rate for difficult tracheal intubation performed by experienced physicians; whether this technique improves the success rate for normal intubations when performed by inexperienced personnel as well is unknown. Therefore, the authors compared the success rate of direct laryngoscopy versus the GlideScope technique performed by personnel inexperienced in tracheal intubations.

Methods

Twenty volunteers, who had had only manikin training for tracheal intubation, attempted 5 intubations with either technique in patients scheduled for general anesthesia within a time limit of 120 s.

Results

Two hundred patients were divided into 2 groups for intubation via direct laryngoscopy (n = 100) or the GlideScope technique (n = 100). Between groups, there was neither a clinically relevant difference in the anthropometric data nor in the medication used for anesthesia. The overall success rate was 93% for the GlideScope technique versus 51% for direct laryngoscopy (P < 0.01). Time for intubation was 89 +/- 35 s for direct laryngoscopy versus 63 +/- 30 s for GlideScope technique (P < 0.01).

Conclusion

Tracheal intubation is the preferred technique to secure the airways in patients with a high risk of aspiration and is important in emergency medicine. Direct laryngoscopy with the Macintosh blade has a success rate of only 51% in our subjects. Using the GlideScope technique, a success rate of more than 90% within 120 s can be achieved after the first attempt, even in personnel untrained in intubation.
Glucose Infusion Suppresses Surgery-induced Muscle Protein Breakdown by Inhibiting Ubiquitin-proteasome Pathway in Rats
Authors: Mikura Mayumi , Yamaoka Ippei , Doi Masako , Kawano Yuichi , Nakayama Mitsuo , Nakao Reiko , Hirasaka Katsuya , Okumura Yuushi , Nikawa Takeshi
Published: December 2008

Background

It appears to have been well established that after surgery, protein catabolism is accelerated and glucose infusion suppresses the catabolic reactions. However, in the early postoperative period, the effects of surgical stress and glucose infusion on muscle protein catabolism and the related mechanisms remain unclear.

Methods

Rats undergoing laparotomy were infused with acetated Ringer's solution (10 ml x kg(-1) x h(-1)) without glucose (control) or containing 1% or 5% glucose. The infusion was continued for a further 4 h after the surgical treatment. The catabolic index, excretion of urinary nitrogen and 3-methylhistidine, and release of tyrosine and 3-methylhistidine from isolated muscle were determined. Furthermore, muscular mRNA expression of proteolytic-related genes (atrogin-1/MAFbx, muscle ring finger-1, mu- and m-calpain, and cathepsin L and H) and phosphorylation of components of insulin signaling (forkhead box O3 and protein kinase B) were evaluated.

Results

Surgery increased the catabolic index, and this increase was suppressed by glucose infusion (both 1% and 5%). In the control group, mRNA expression of atrogin-1/MAFbx and muscle ring finger-1 was increased, and they were suppressed in the two glucose groups. Furthermore, insulin signaling (phosphorylation of protein kinase B and forkhead box O3) in muscles was stimulated by glucose infusion.

Conclusion

The present study indicates that glucose infusion, even at a relatively low rate, suppresses muscle protein breakdown in the early postoperative period. The mechanism of this effect is related to the suppression of the ubiquitin-proteasome pathway, accompanied by activation of insulin signaling.
Preoperative and Intraoperative Predictors of Cardiac Adverse Events after General, Vascular, and Urological Surgery
Authors: Kheterpal Sachin , O’Reilly Michael , Englesbe Michael J. , Rosenberg Andrew L. , Shanks Amy M. , Zhang Lingling , Rothman Edward D. , Campbell Darrell A. , Tremper Kevin K.
Published: December 2008

Background

The authors sought to determine the incidence and risk factors for perioperative cardiac adverse events (CAEs) after noncardiac surgery using detailed preoperative and intraoperative hemodynamic data.

Methods

The authors conducted a prospective observational study at a single university hospital from 2002 to 2006. All American College of Surgeons-National Surgical Quality Improvement Program patients undergoing general, vascular, and urological surgery were included. The CAE outcome definition included cardiac arrest, non-ST elevation myocardial infarction, Q-wave myocardial infarction, and new clinically significant cardiac dysrhythmia within the first 30 postoperative days.

Results

Four years of data demonstrated that of 7,740 noncardiac operations, 83 patients (1.1%) experienced a CAE within 30 days. Nine independent predictors were identified (P < or = 0.05): age > or = 68, body mass index > or = 30, emergent surgery, previous coronary intervention or cardiac surgery, active congestive heart failure, cerebrovascular disease, hypertension, operative duration > or = 3.8 h, and the administration of 1 or more units of packed red blood cells intraoperatively. The c-statistic of this model was 0.81 +/- 0.02. Univariate analysis demonstrated that high-risk patients experiencing a CAE were more likely to experience an episode of mean arterial pressure < 50 mmHg (6% vs. 24%, P = 0.02), experience an episode of 40% decrease in mean arterial pressure (26% vs. 53%, P = 0.01), and an episode of heart rate > 100 (22% vs. 34%, P = 0.05).

Conclusions

In comparison with current risk stratification indices, the inclusion of intraoperative elements improves the ability to predict a perioperative CAE after noncardiac surgery.
Pharmacokinetic-Pharmacodynamic Model for the Reversal of Neuromuscular Blockade by Sugammadex
Authors: Ploeger Bart A. , Smeets Jean , Strougo Ashley , Drenth Henk-Jan , Ruigt Ge , Houwing Natalie , Danhof Meindert
Published: December 2008

Background

Sugammadex selectively binds steroidal neuromuscular blocking drugs, leading to reversal of neuromuscular blockade. The authors developed a pharmacokinetic-pharmacodynamic model for reversal of neuromuscular blockade by sugammadex, assuming that reversal results from a decrease of free drug in plasma and/or neuromuscular junction. The model was applied for predicting the interaction between sugammadex and rocuronium or vecuronium.

Methods

Noninstantaneous equilibrium of rocuronium-sugammadex complex formation was assumed in the pharmacokinetic-pharmacodynamic interaction model. The pharmacokinetic parameters for the complex and sugammadex alone were assumed to be identical. After development of a pharmacokinetic-pharmacodynamic model for rocuronium alone, the interaction model was optimized using rocuronium and sugammadex concentration data after administration of 0.1-8 mg/kg sugammadex 3 min after administration of 0.6 mg/kg rocuronium. Subsequently, the predicted reversal of neuromuscular blockade by sugammadex was compared with data after administration of up to 8 mg/kg sugammadex at reappearance of second twitch of the train-of-four; or 3, 5, or 15 min after administration of 0.6 mg/kg rocuronium. Finally, the model was applied to predict reversal of vecuronium-induced neuromuscular blockade.

Results

Using the in vitro dissociation constants for the binding of rocuronium and vecuronium to sugammadex, the pharmacokinetic-pharmacodynamic interaction model adequately predicted the increase in total rocuronium and vecuronium plasma concentrations and the time-course of reversal of neuromuscular blockade.

Conclusions

Model-based evaluation supports the hypothesis that reversal of rocuronium- and vecuronium-induced neuromuscular blockade by sugammadex results from a decrease in the free rocuronium and vecuronium concentration in plasma and neuromuscular junction. The model is useful for prediction of reversal of rocuronium and vecuronium-induced neuromuscular blockade with sugammadex.
Prevention of the Pulmonary Vasoconstrictor Effects of HBOC-201 in Awake Lambs by Continuously Breathing Nitric Oxide
Authors: Yu Binglan , Volpato Gian Paolo , Chang Keqin , Bloch Kenneth D. , Zapol Warren M.
Published: December 2008

Background

Hemoglobin-based oxygen-carrying solutions (HBOC) provide emergency alternatives to blood transfusion to carry oxygen to tissues without the risks of disease transmission or transfusion reaction. Two primary concerns hampering the clinical acceptance of acellular HBOC are the occurrence of systemic and pulmonary vasoconstriction and the maintenance of the heme-iron in the reduced state (Fe2+). We recently demonstrated that pretreatment with inhaled nitric oxide prevents the systemic hypertension induced by HBOC-201 (polymerized bovine hemoglobin) infusion in awake mice and sheep without causing methemoglobinemia. However, the impact of HBOC-201 infusion with or without inhaled nitric oxide on pulmonary vascular tone has not yet been examined.

Methods

The pulmonary and systemic hemodynamic effects of breathing nitric oxide both before and after the administration of HBOC-201 were determined in healthy, awake lambs.

Results

Intravenous administration of HBOC-201 (12 ml/kg) induced prolonged systemic and pulmonary vasoconstriction. Pretreatment with inhaled nitric oxide (80 parts per million [ppm] for 1 h) prevented the HBOC-201--induced increase in mean arterial pressure but not the increase of pulmonary arterial pressure, systemic vascular resistance, or pulmonary vascular resistance. Pretreatment with inhaled nitric oxide (80 ppm for 1 h) followed by breathing a lower concentration of nitric oxide (5 ppm) during and after HBOC-201 infusion prevented systemic and pulmonary vasoconstriction without increasing methemoglobin levels.

Conclusions

These findings demonstrate that pretreatment with inhaled nitric oxide followed by breathing a lower concentration of the gas during and after administration of HBOC-201 may enable administration of an acellular hemoglobin substitute without vasoconstriction while preserving its oxygen-carrying capacity.
Midazolam Inhibits Tumor Necrosis Factor-α–induced Endothelial Activation
Authors: Joo Hee Kyoung , Oh Sae Cheol , Cho Eun Jung , Park Kyoung Sook , Lee Ji Young , Lee Eun Ji , Lee Sang Ki , Kim Hyo Shin , Park Jin Bong , Jeon Byeong Hwa
Published: December 2008

Background

Midazolam is widely used as an intravenous sedative. However, the role of midazolam on vascular endothelial activation is still unknown. The present study explores the action of midazolam on endothelial activation and its role to peripheral benzodiazepine receptor (PBR) in cultured human umbilical vein endothelial cells.

Methods

Intracellular localization of PBR in human umbilical vein endothelial cells was visualized with immunofluorescent staining. Monocyte adhesion and vascular cell adhesion molecule-1 expression were measured with monocyte adhesion assay and Western blot analysis. Involvement of PBR was assessed by using specific antagonists and small interfering RNA against PBR.

Results

PBR was localized in the mitochondria of human umbilical vein endothelial cells. Midazolam significantly inhibited tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 and monocyte adhesion in a dose-dependent manner (1-30 microM). The midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression and monocyte adhesion were inhibited by the pretreatment of PK11195 and not inhibited by the flumazenil. Transfection of small interfering RNA for PBR decreased the expression of PBR (18 kDa) in human umbilical vein endothelial cells. Midazolam-mediated suppression on the tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression was abrogated by the transfection of small interfering RNA for PBR.

Conclusion

These results suggest that midazolam has an inhibitory action on the endothelial activation and that its action is related to the activation of peripheral benzodiazepine receptor localized in mitochondria of the endothelial cells.
Modulation of Opioid Actions by Nitric Oxide Signaling
Authors: Toda Noboru , Kishioka Shiroh , Hatano Yoshio , Toda Hiroshi , Warner David S. , Warner Mark A.
Published: December 2008

Nitric oxide (NO) plays pivotal roles in controlling physiological functions, participates in pathophysiological intervention, and is involved in mechanisms underlying beneficial or untoward actions of therapeutic agents. Endogenous nitric oxide is formed by three isoforms of nitric oxide synthase: endothelial, neurogenic and inducible. The former two are constitutively present mainly in the endothelium and nervous system, respectively, and the latter one is induced by lipopolysaccharides or cytokines mainly in mitochondria and glial cells. Constitutively formed nitric oxide modulates the actions of morphine and related analgesics by either enhancing or reducing antinociception. Tolerance to and dependence on morphine or its withdrawal syndrome are likely prevented by nitric oxide synthase inhibition. Information concerning modulation of morphine actions by nitric oxide is undoubtedly useful in establishing new strategies for efficient antinociceptive treatment and for minimizing noxious and unintended reactions.
CPEB regulation of human cellular senescence, energy metabolism, and p53 mRNA translation
Authors: Burns David M. , Richter Joel D.
Published: December 2008

Cytoplasmic polyadenylation element-binding protein (CPEB) stimulates polyadenylation and translation in germ cells and neurons. Here, we show that CPEB-regulated translation is essential for the senescence of human diploid fibroblasts. Knockdown of CPEB causes skin and lung cells to bypass the M1 crisis stage of senescence; reintroduction of CPEB into the knockdown cells restores a senescence-like phenotype. Knockdown cells that have bypassed senescence undergo little telomere erosion. Surprisingly, knockdown of exogenous CPEB that induced a senescence-like phenotype results in the resumption of cell growth. CPEB knockdown cells have fewer mitochondria than wild-type cells and resemble transformed cells by having reduced respiration and reactive oxygen species (ROS), normal ATP levels, and enhanced rates of glycolysis. p53 mRNA contains cytoplasmic polyadenylation elements in its 3′ untranslated region (UTR), which promote polyadenylation. In CPEB knockdown cells, p53 mRNA has an abnormally short poly(A) tail and a reduced translational efficiency, resulting in an ∼50% decrease in p53 protein levels. An shRNA-directed reduction in p53 protein by about 50% also results in extended cellular life span, reduced respiration and ROS, and increased glycolysis. Together, these results suggest that CPEB controls senescence and bioenergetics in human cells at least in part by modulating p53 mRNA polyadenylation-induced translation.
The Iws1:Spt6:CTD complex controls cotranscriptional mRNA biosynthesis and HYPB/Setd2-mediated histone H3K36 methylation
Authors: Yoh Sunnie M. , Lucas Joseph S. , Jones Katherine A.
Published: December 2008

Many steps in gene expression and mRNA biosynthesis are coupled to transcription elongation and organized through the C-terminal domain (CTD) of the large subunit of RNA polymerase II (RNAPII). We showed recently that Spt6, a transcription elongation factor and histone H3 chaperone, binds to the Ser2P CTD and recruits Iws1 and the REF1/Aly mRNA export adaptor to facilitate mRNA export. Here we show that Iws1 also recruits the HYPB/Setd2 histone methyltransferase to the RNAPII elongation complex and is required for H3K36 trimethylation (H3K36me3) across the transcribed region of the c-Myc, HIV-1, and PABPC1 genes in vivo. Interestingly, knockdown of either Iws1 or HYPB/Setd2 also enhanced H3K27me3 at the 5′ end of the PABPC1 gene, and depletion of Iws1, but not HYPB/Setd2, increased histone acetylation across the coding regions at the HIV-1 and PABPC1 genes in vivo. Knockdown of HYPB/Setd2, like Iws1, induced bulk HeLa poly(A)+ mRNAs to accumulate in the nucleus. In vitro, recombinant Spt6 binds selectively to a stretch of uninterrupted consensus repeats located in the N-terminal half of the CTD and recruits Iws1. Thus Iws1 connects two distinct CTD-binding proteins, Spt6 and HYPB/Setd2, in a megacomplex that affects mRNA export as well as the histone modification state of active genes.
Riboswitch RNAs: using RNA to sense cellular metabolism
Authors: Henkin Tina M.
Published: December 2008

Riboswitches are RNA elements that undergo a shift in structure in response to binding of a regulatory molecule. These elements are encoded within the transcript they regulate, and act in cis to control expression of the coding sequence(s) within that transcript; their function is therefore distinct from that of small regulatory RNAs (sRNAs) that act in trans to regulate the activity of other RNA transcripts. Riboswitch RNAs control a broad range of genes in bacterial species, including those involved in metabolism or uptake of amino acids, cofactors, nucleotides, and metal ions. Regulation occurs as a consequence of direct binding of an effector molecule, or through sensing of a physical parameter such as temperature. Here we review the global role of riboswitch RNAs in bacterial cell metabolism.
Fission yeast Ccq1 is telomerase recruiter and local checkpoint controller
Authors: Tomita Kazunori , Cooper Julia Promisel
Published: December 2008

Telomeres recruit telomerase and differentiate chromosome ends from sites of DNA damage. Although the DNA damage checkpoint PI3-kinases ATM and ATR localize to telomeres and promote telomerase activation, activation of their downstream checkpoint pathway targets is inhibited. Here, we show that the fission yeast telomeric protein Ccq1 is required for telomerase recruitment and inhibition of ATR target activation at telomeres. The loss of Ccq1 results in progressive telomere shortening and persistent ATR-dependent activation of Chk1. Unlike the checkpoint activation that follows loss of telomerase, this checkpoint activation occurs prior to detectable levels of critically short telomeres. When ccq1Δ telomeres do become critically short, activated Chk1 promotes an unusual homologous recombination-based telomere maintenance process. We find that the previously reported meiotic segregation defects of cells lacking Ccq1 stem from its role in telomere maintenance rather than from a role in formation of the meiotic bouquet. These findings demonstrate the existence of a novel telomerase recruitment factor that also serves to suppress local checkpoint activation.
MicroRNA target prediction by expression analysis of host genes
Authors: Gennarino Vincenzo Alessandro , Sardiello Marco , Avellino Raffaella , Meola Nicola , Maselli Vincenza , Anand Santosh , Cutillo Luisa , Ballabio Andrea , Banfi Sandro
Published: December 2008

MicroRNAs (miRNAs) are small noncoding RNAs that control gene expression by inducing RNA cleavage or translational inhibition. Most human miRNAs are intragenic and are transcribed as part of their hosting transcription units. We hypothesized that the expression profiles of miRNA host genes and of their targets are inversely correlated and devised a novel procedure, HOCTAR (host gene oppositely correlated targets), which ranks predicted miRNA target genes based on their anti-correlated expression behavior relative to their respective miRNA host genes. HOCTAR is the first tool for systematic miRNA target prediction that utilizes the same set of microarray experiments to monitor the expression of both miRNAs (through their host genes) and candidate targets. We applied the procedure to 178 human intragenic miRNAs and found that it performs better than currently available prediction softwares in pinpointing previously validated miRNA targets. The high-scoring HOCTAR predicted targets were enriched in Gene Ontology categories, which were consistent with previously published data, as in the case of miR-106b and miR-93. By means of overexpression and loss-of-function assays, we also demonstrated that HOCTAR is efficient in predicting novel miRNA targets and we identified, by microarray and qRT-PCR procedures, 34 and 28 novel targets for miR-26b and miR-98, respectively. Overall, we believe that the use of HOCTAR significantly reduces the number of candidate miRNA targets to be tested compared to the procedures based solely on target sequence recognition. Finally, our data further confirm that miRNAs have a significant impact on the mRNA levels of most of their targets.