Nuclear FAK promotes cell proliferation and survival through FERM-enhanced p53 degradation

FAK is known as an integrin- and growth factor-associated tyrosine kinase promoting cell motility. Here we show that, during mouse development, FAK inactivation results in p53- and p21-dependent mesodermal cell growth arrest. Reconstitution of primary FAK-/-p21-/- fibroblasts revealed that FAK, in a kinase-independent manner, facilitates p53 turnover via enhanced Mdm2-dependent p53 ubiquitination. p53 inactivation by FAK required FAK FERM F1 lobe binding to p53, FERM F2 lobe-mediated nuclear localization, and FERM F3 lobe for connections to Mdm2 and proteasomal degradation. Staurosporine or loss of cell adhesion enhanced FERM-dependent FAK nuclear accumulation. In primary human cells, FAK knockdown raised p53-p21 levels and slowed cell proliferation but did not cause apoptosis. Notably, FAK knockdown plus cisplatin triggered p53-dependent cell apoptosis, which was rescued by either full-length FAK or FAK FERM re-expression. These studies define a scaffolding role for nuclear FAK in facilitating cell survival through enhanced p53 degradation under conditions of cellular stress.

PyK2 and FAK connections to p190Rho guanine nucleotide exchange factor regulate RhoA activity, focal adhesion formation, and cell motility

Integrin binding to matrix proteins such as fibronectin (FN) leads to formation of focal adhesion (FA) cellular contact sites that regulate migration. RhoA GTPases facilitate FA formation, yet FA-associated RhoA-specific guanine nucleotide exchange factors (GEFs) remain unknown. Here, we show that proline-rich kinase-2 (Pyk2) levels increase upon loss of focal adhesion kinase (FAK) in mouse embryonic fibroblasts (MEFs). Additionally, we demonstrate that Pyk2 facilitates deregulated RhoA activation, elevated FA formation, and enhanced cell proliferation by promoting p190RhoGEF expression. In normal MEFs, p190RhoGEF knockdown inhibits FN-associated RhoA activation, FA formation, and cell migration. Knockdown of p190RhoGEF-related GEFH1 does not affect FA formation in FAK^−/− or normal MEFs. p190RhoGEF overexpression enhances RhoA activation and FA formation in MEFs dependent on FAK binding and associated with p190RhoGEF FA recruitment and tyrosine phosphorylation. These studies elucidate a compensatory function for Pyk2 upon FAK loss and identify the FAK–p190RhoGEF complex as an important integrin-proximal regulator of FA formation during FN-stimulated cell motility.

Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice

AIMS/HYPOTHESIS

The unfolded protein response (UPR) in endoplasmic reticulum (ER) and autophagy are known to be related. We investigated the role of autophagy in UPR of pancreatic beta cells and the susceptibility of autophagy-deficient beta cells to the ER stress that is implicated in the development of diabetes.

METHODS

Rat insulin promoter (RIP)-Cre(+);autophagy-related 7 (Atg7)(F/W) mice were bred with ob/w mice to derive RIP-Cre(+);Atg7(F/F)-ob/ob mice and to induce ER stress in vivo. GFP-LC3(+)-ob/ob mice were generated to examine in vivo autophagic activity. Real-time RT-PCR was performed to study the expression of the genes of the UPR machinery. Proteolysis was assessed by determining release of incorporated radioactive leucine.

RESULTS

Production of UPR machinery was reduced in autophagy-deficient beta cells, which was associated with diminished production of p85α and p85β regulatory subunits of phosphoinositide 3-kinase. Because of compromised UPR machinery, autophagy-deficient beta cells were susceptible to ER stressors in vitro. When mice with beta cell-specific autophagy deficiency, which have mild hyperglycaemia, were bred with ob/ob mice to induce ER stress in vivo, severe diabetes developed, which was accompanied by an increase in beta cell death and accumulation of reactive oxygen species. The increased demand for UPR present in obesity was unmet in autophagy-deficient beta cells. Autophagy level and autophagic activity were enhanced by lipid, while proteolysis was reduced.

CONCLUSIONS/INTERPRETATION

These results suggest that autophagy is important for intact UPR machinery and appropriate UPR in response to lipid injury that increases demand for UPR. Autophagy deficiency in pancreatic beta cells may contribute to the progression from obesity to diabetes.

Syndecan-2 mediates adhesion and proliferation of colon carcinoma cells

Syndecan-2 is a transmembrane heparan sulfate proteoglycan whose function at the cell surface is unclear. In this study, we examined the function of syndecan-2 in colon cancer cell lines. In several colon cancer cell lines, syndecan-2 was highly expressed compared with normal cell lines. In contrast, syndecan-1 and -4 were decreased. Cell biological studies using the extracellular domain of recombinant syndecan-2 (2E) or spreading assay with syndecan-2 antibody-coated plates showed that syndecan-2 mediated adhesion and cytoskeletal organization of colon cancer cells. This interaction was critical for the proliferation of colon carcinoma cells. Blocking with 2E or antisense syndecan-2 cDNA induced G(0)/G(1) cell cycle arrest with concomitantly increased expression of p21, p27, and p53. Furthermore, blocking of syndecan-2 through antisense syndecan-2 cDNA significantly reduced tumorigenic activity in colon carcinoma cells. Therefore, increased syndecan-2 expression appears to be a critical for colon carcinoma cell behavior, and syndecan-2 regulates tumorigenic activity through regulation of adhesion and proliferation in colon carcinoma cells.

Insensitivity of blocking probabilities in a circuit-switching network

Consider a network of nodes (switches) and connecting links. Each link consists of a group of channels (trunks). A call instantaneously seizes channels along a route between the originating and terminating node, holds them for a randomly distributed length of time and frees them instantaneously at the end of the call. If no channels are available, the call is blocked. For special networks with exponential call holding times, Erlang has shown that the steady-state probabilities are in product form. In this paper, we extend this work to general networks and show that if for each pair of nodes there is a unique route, then the blocking probabilities are in product form and are insensitive to the call holding-time distribution, which means that they depend on the call duration only through its mean.

Evaluation of ease of intubation with the GlideScope�or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy

The GlideScope is a new video laryngoscope developed for management of the difficult airway. We compared the GlideScope with the Macintosh laryngoscope in simulated easy and difficult laryngoscopy. Twenty anaesthetists were allowed three attempts to intubate in each of four laryngoscopy scenarios in a high fidelity simulator. In the simulated easy laryngoscopy scenarios, the anaesthetists took longer to intubate using the GlideScope than the Macintosh laryngoscope (mean (SD) 19.0 (9.7) s vs. 12.7 (5.9) s, respectively; p = 0.006). There was no difference in the number of successful intubations, ease of intubation or choice of intubating device. In the simulated difficult laryngoscopy scenarios, the anaesthetists took less time to intubate using the GlideScope (23.5 (12.7) s vs. 70.5 (101.2) s, respectively; p = 0.001). The slightly higher success rate with the GlideScope was not statistically significant (20/20 vs. 18/20, respectively; p = 0.5). However, the anaesthetists found it easier to intubate using the GlideScope (median (interquartile range [range]) 1 (1-2 [1-2]) vs. 2 (2-3 [1-3]), respectively; p < 0.0001).

A FAK-p120RasGAP-p190RhoGAP complex regulates polarity in migrating cells

Directional motility is a complex process requiring the spatiotemporal integration of signals that regulate cytoskeletal changes, and the establishment of an anteroposterior or polarized cell axis. Focal adhesion kinase (FAK) promotes cell migration, but a molecular role for FAK in promoting cell polarity remains undefined. Here, using wound healing and Golgi-reorientation analyses, we show that fibroblast, endothelial and carcinoma polarity during cell migration requires FAK and is associated with a complex between FAK, p120RasGAP and p190RhoGAP (p190A), leading to p190A tyrosine phosphorylation. Fibronectin-integrin-mediated FAK activation and phosphorylation promote SH2-mediated binding of p120RasGAP to FAK and FAK-mediated p190A tyrosine phosphorylation. The association of p120RasGAP with FAK facilitates the formation of a FAK-p120RasGAP-p190A complex targeted to leading-edge focal adhesions by FAK. Knockdown of p120RasGAP, mutation of FAK Y397 or inhibition of FAK activity prevent the association of FAK with p190A and subsequent tyrosine phosphorylation of p190A, and result in the loss of cell polarity. Because reconstitution of FAK-null fibroblasts with FAK or a Pyk2-FAK chimera restore the normal decrease in RhoA GTP binding upon cell spreading on fibronectin, our studies support a model whereby FAK activity facilitates the recruitment and stabilization of a p120RasGAP-p190A complex at leading-edge focal adhesions connected to the transient inhibition of RhoA activity and the regulation of cell polarity.

Investigation of the roles of toxin-coregulated pili and mannose-sensitive hemagglutinin pili in the pathogenesis of Vibrio cholerae O139 infection

In this study, adult volunteers were fed tcpA and mshA deletion mutants of V. cholerae O139 strain CVD 112 to determine the role of toxin-coregulated pili (TCP) and mannose-sensitive hemagglutinin (MSHA) in intestinal colonization. Eight of 10 volunteers who received CVD 112 or CVD 112 delta mshA shed the vaccine strains in their stools; the geometric mean peak excretion for both groups was 1.4 x 10(5) CFU/g of stool. In contrast, only one of nine recipients of CVD 112 delta tcpA shed vibrios in his stool (P < 0.01); during the first 24 h after inoculation, 3 x 10(2) CFU/g was recovered from this volunteer. All recipients of CVD 112 and 8 (80%) of the recipients of CVD 112 delta mshA developed at least a fourfold rise in vibriocidal titer after immunization. In contrast, only one (11%) of the nine recipients of CVD 112 delta tcpA developed a fourfold rise in vibriocidal titer (P < 0.01). We conclude that TCP are an important colonization factor of V. cholerae O139 and probably of El Tor V. cholerae O1. In contrast, MSHA does not appear to promote intestinal colonization in humans.

CAS agar diffusion assay for the measurement of siderophores in biological fluids

We developed a simple and universal method, by modifying the universal CAS (Chrome azurol S) assay, measuring siderophores in various biological fluids. We named the assay as CAS agar diffusion (CASAD) assay. CAS plate devoid of nutrients was prepared by using Bacto-agar (1.5%, w/v) as a matrix. Holes with 5-mm-diameter were punched on the CAS agar plate. Each hole was added by 35 microl of the test fluids containing Desferal that was twofold serially diluted. After incubating at 37 degrees C or room temperature for 4-8 h, the size of orange haloes formed around the holes was measured. The size of orange haloes correlated well with the concentration of Desferal in all the biological fluids tested in this study. CASAD assay showed consistent results in wide pH range from 5 to 9. Addition of iron to the test fluids containing Desferal decreased the size of orange haloes in a dose-dependent manner, which suggests that the CASAD assay detects only iron non-bound siderophore. These results suggest that CASAD assay would serve as a simple, stable, and highly reproducible test for screening and quantitative siderophore analysis in biological fluids.

Phosphorylation of Focal Adhesion Kinase at Tyrosine 861 Is Crucial for Ras Transformation of Fibroblasts

Although elevated expression and increased tyrosine phosphorylation of focal adhesion kinase (FAK) are crucial for tumor progression, the mechanism by which FAK promotes oncogenic transformation is unclear. We have therefore determined the role of FAK phosphorylation at tyrosine 861 in the oncogenic transformation of NIH3T3 fibroblasts. FAK phosphorylation at tyrosine 861 was increased in both constitutively H-Ras-transformed and H-Ras-inducible NIH3T3 cells, in parallel with cell transformation. However, H-Ras-inducible cells transfected with the nonphosphorylatable mutant FAK Y861F showed decreased migration/invasion, focus forming activity and anchorage-independent growth, compared with either wild-type or kinase-defective FAK. In contrast to unaltered FAK/Src activity, the association of FAK and p130(CAS) was decreased in FAK Y861F-transfected cells, and FAK phosphorylation at tyrosine 861 enhanced this association in vitro. Consistently, FAK Y861F-transfected cells were defective in activation of c-Jun NH(2)-terminal kinase and in expression of matrix metalloproteinase-9 during transformation. Taken together, these results strongly suggest that FAK phosphorylation at tyrosine 861 is crucial for H-Ras-induced transformation through regulation of the association of FAK with p130(CAS).

Distinct FAK-Src activation events promote alpha5beta1 and alpha4beta1 integrin-stimulated neuroblastoma cell motility

Signals from fibronectin-binding integrins promote neural crest cell motility during development in part through protein-tyrosine kinase (PTK) activation. Neuroblastoma (NB) is a neural crest malignancy with high metastatic potential. We find that alpha4 and alpha5 integrins are present in late-stage NB tumors and cell lines derived thereof. To determine the signaling connections promoting either alpha4beta1- or alpha5beta1-initiated NB cell motility, pharmacological, dominant negative and short-hairpin RNA (shRNA) inhibitory approaches were undertaken. shRNA knockdown revealed that alpha5beta1-stimulated NB motility is dependent upon focal adhesion kinase (FAK) PTK, Src PTK and p130Cas adapter protein expression. Cell reconstitution showed that FAK catalytic activity is required for alpha5beta1-stimulated Src activation in part through direct FAK phosphorylation of Src at Tyr-418. Alternatively, alpha4beta1-stimulated NB cell motility is dependent upon Src and p130Cas but FAK is not essential. Catalytically inactive receptor protein-tyrosine phosphatase-alpha overexpression inhibited alpha4beta1-stimulated NB motility and Src activation consistent with alpha4-regulated Src activity occurring through Src Tyr-529 dephosphorylation. In alpha4 shRNA-expressing NB cells, alpha4beta1-stimulated Src activation and NB cell motility were rescued by wild type but not cytoplasmic domain-truncated alpha4 re-expression. These studies, supported by results using reconstituted fibroblasts, reveal that alpha4beta1-mediated Src activation is mechanistically distinct from FAK-mediated Src activation during alpha5beta1-mediated NB migration and support the evaluation of inhibitors to alpha4, Src and FAK in the control of NB tumor progression.

A Comparison of the GlideScope® with the Macintosh Laryngoscope for Tracheal Intubation in Patients with Simulated Difficult Airway

We compared the use of the GlideScope® and the conventional Macintosh laryngoscope in a simulated difficult airway. The primary hypothesis was that time to intubation would be shorter using the GlideScope® than using the Macintosh laryngoscope.

After obtaining approval from the ethics committee and written informed consent, we recruited 60 ASA 1 and 2 patients to our randomized controlled trial. Group G (n=30) had tracheal intubation performed using the GlideScope® and Group M (n=30) were intubated using a Macintosh laryngoscope. We simulated a difficult airway in each patient by having an experienced assistant provide in-line manual stabilization of the head and neck. We recorded the best laryngeal view; difficulty of the tracheal intubation; time taken for successful tracheal intubation; manoeuvre needed to aid tracheal intubation and complications associated with the tracheal intubation.

The median Cormack and Lehane grade was significantly better in Group G than Group M. Group G had a significantly shorter intubation time than group M (mean 41.8s±SD 20.2 vs mean 56.2s±26.6, P<0.05).

The GlideScope® improved the laryngeal view and decreased time for tracheal intubation time when compared with the Macintosh laryngoscope in patients with simulated difficult airway. The GlideScope® may be a good alternative for managing the difficult airway but clinical trials evaluating its use on patients with an actual difficult airway are needed.

Incidence and risk factors for chronic pain after caesarean section under spinal anaesthesia

This study investigated the incidence and risk factors associated with chronic pain after elective caesarean section under spinal anaesthesia in an Asian population. A prospective cohort study was conducted among subjects who underwent elective caesarean section under spinal anaesthesia, with morphine patient-controlled analgesia administered for 24 hours postoperatively. Perioperative, surgical and obstetric factors were investigated prospectively. Phone surveys were conducted to identify risk factors associated with chronic pain. A total of 857 subjects completed both the perioperative study and phone survey. The incidence of wound scar pain for three months after surgery was 9.2% (79). Of the 51 subjects with persistent pain at the time of subsequent survey, 9.8% (n = 5) had constant pain, 9.8% (n = 5) had daily pain and 23.5% (n = 12) had pain intermittently, at an interval of days. The independent risk factors for development of chronic pain were higher pain scores recalled in the immediate postoperative period (odds ratio [OR, 95% confidence interval] 1.348 [1.219 to 1.490], P = 0.0001), pain present elsewhere (OR 2.471 [1.485 to 4.112], P = 0.001) and non-private insurance status (OR 1.679 [1.034 to 2.727], P = 0.036). The two most common sites of pain other than wound pain were back pain (n = 316) and migraine (n = 87).

Automated regular boluses for epidural analgesia: a comparison with continuous infusion

BACKGROUND

Intermittent epidural bolus dosing is a method of drug delivery that can prolong the duration of labour analgesia induced by a combined spinal epidural (CSE). In this randomized, double-blinded study, we compared the analgesic efficacy of two drug delivery systems: regular intermittent epidural boluses and continuous epidural infusion and assessed the incidence of breakthrough pain after CSE.

METHODS

With the approval of the Hospital Ethics Committee, we recruited 60 parturients into this randomized controlled trial. A CSE was performed with intrathecal fentanyl 25 mug in all patients. The parturients were then randomly allocated into two groups. The infusion group received a continuous epidural infusion of levobupivacaine 0.1% with fentanyl 2 microg/mL at a rate of 10 mL/h. The bolus group received 5-mL epidural boluses every half hour. The sample size was computed to detect a 40% reduction in the rate of breakthrough pain.

RESULTS

The bolus group had a lower incidence of breakthrough pain than the infusion group (10% vs. 37%, P < 0.05). The bolus group also had significantly higher satisfaction scores for labour analgesia: 97+/-8 (mean+/-SD) vs. 89+/-7 (P < 0.05).

CONCLUSION

Automated regular bolus delivery of epidural analgesia when compared with continuous infusion decreased the incidence of breakthrough pain and increased maternal satisfaction. In a busy obstetric unit, this may also serve to decrease the anesthetists' workload.

Syndecan-4 regulates localization, activity and stability of protein kinase C-alpha

During cell-matrix adhesion, syndecan-4 transmembrane heparan sulphate proteoglycan plays a critical role in the formation of focal adhesions and stress fibres. We have shown previously that the syndecan-4 cytoplasmic domain directly binds to and activates PKC-alpha (protein kinase C-alpha) in vitro [Oh, Woods and Couchman (1997) J. Biol. Chem. 272, 8133-8136]. However, whether syndecan-4 has the same activity in vivo needs to be addressed. Using mammalian two-hybrid assays, we showed that syndecan-4 interacted with PKC-alpha in vivo and that this interaction was mediated through syndecan-4 cytoplasmic domain. Furthermore, the activation of PKC increased the extent of interaction between syndecan-4 and PKC-alpha. Overexpression of syndecan-4, but not a mutant lacking its cytoplasmic domain, specifically increased the level of endogenous PKC-alpha and enhanced the translocation of PKC-alpha into both detergent-insoluble and membrane fractions. In addition, rat embryo fibroblasts overexpressing syndecan-4 exhibited a slowed down-regulation of PKC-alpha in response either to a prolonged treatment with PMA or to maintaining cells in suspension culture. PKC-alpha immunocomplex kinase assays also showed that syndecan-4 overexpression increased the activity of membrane PKC-alpha. Taken together, these results suggest that syndecan-4 interacts with PKC-alpha in vivo and regulates its localization, activity and stability.

Changes in DNA 8-hydroxyguanine levels, 8-hydroxyguanine repair activity, and hOGG1 and hMTH1 mRNA expression in human lung alveolar epithelial cells induced by crocidolite asbestos

We examined 8-hydroxyguanine (8-OH-Gua) formation and 8-OH-Gua repair enzyme activity in pulmonary type-II-like epithelial cells to determine whether oxidative stress induced by asbestos plays a role in its carcinogenic mechanism. A549 cells were incubated with crocidolite asbestos at concentrations of 0, 10, 50 and 100 microg/ml over 27 h. We then evaluated 8-OH-Gua formation, 8-OH-Gua repair enzyme activity and gene expression of 8-oxoguanine-DNA glycosylase 1 (hOGG1) and human MUtT homologue (hMTH1). This was done using a high-performance liquid chromatography system equipped with an electrochemical detector, endonuclease nicking assay and reverse transcription polymerase chain reaction, respectively. Crocidolite induced the formation of 8-OH-Gua in DNA at concentrations of 50 and 100 microg/ml. 8-OH-Gua levels increased at 9 h and had declined to near baseline at 27 h, whereas 8-OH-Gua repair enzyme activity peaked at 18 h post-crocidolite exposure. hOGG1 and hMTH1 mRNA levels were also increased by crocidolite exposure. These data suggest that crocidolite asbestos is associated with epithelial cell injury in the process of carcinogenesis through oxidative stress.

A randomized comparison of automated intermittent mandatory boluses with a basal infusion in combination with patient-controlled epidural analgesia for labor and delivery

BACKGROUND

Automated mandatory boluses (AMB), when used in place of a continuous basal infusion, have been shown to reduce overall local anesthetic consumption without compromising analgesic efficacy in patient-controlled epidural analgesia (PCEA). We hypothesized that our PCEA+AMB regimen could result in a reduction of breakthrough pain requiring epidural supplementation in comparison with PCEA with a basal infusion (PCEA+BI).

METHODS

We recruited sixty-two healthy ASA I nulliparous parturients in early labor. The parturients were randomized to receive 0.1% ropivacaine+fentanyl 2 μg/mL either via PCEA+BI (PCEA with basal continuous infusion of 5mL/h) or PCEA+AMB (PCEA with AMB of 5 mL every hour instead of a basal infusion) immediately following successful induction of combined spinal-epidural (CSE) analgesia. Block characteristics, incidence of breakthrough pain requiring epidural supplementation, side effects, obstetric outcomes, Apgar scores and overall maternal satisfaction with analgesia were noted.

RESULTS

The time-weighted hourly consumption of ropivacaine (PCEA and clinician supplementation for breakthrough pain) was significantly lower in the PCEA+AMB group (mean=7.6 mL, SD 3.2) compared to the PCEA+BI group (mean=9.3 mL, SD 2.5; P<0.001). The mean time to first PCEA self-bolus following CSE was significantly longer in the PCEA+AMB group compared to the PCEA+BI group (268 min vs. 104 min; P<0.001). Parturients in Group PCEA+AMB also gave higher satisfaction scores. The incidence of breakthrough pain was similar in both groups.

CONCLUSION

PCEA+AMB, when compared to PCEA+BI, confers greater patient satisfaction and a longer duration of effective analgesia after CSE despite reduced analgesic consumption.

Pyk2 inhibition of p53 as an adaptive and intrinsic mechanism facilitating cell proliferation and survival

Pyk2 is a cytoplasmic tyrosine kinase related to focal adhesion kinase (FAK). Compensatory Pyk2 expression occurs upon FAK loss in mice. However, the impact of Pyk2 up-regulation remains unclear. Previous studies showed that nuclear-localized FAK promotes cell proliferation and survival through FAK FERM domain-enhanced p53 tumor suppressor degradation (Lim, S. T., Chen, X. L., Lim, Y., Hanson, D. A., Vo, T. T., Howerton, K., Larocque, N., Fisher, S. J., Schlaepfer, D. D., and Ilic, D. (2008) Mol. Cell 29, 9-22). Here, we show that FAK knockdown triggered p53 activation and G(1) cell cycle arrest in human umbilical vein endothelial cells after 4 days. However, by 7 days elevated Pyk2 expression occurred with a reduction in p53 levels and the release of the G(1) block under conditions of continued FAK knockdown. To determine whether Pyk2 regulates p53, experiments were performed in FAK(-/-)p21(-/-) mouse embryo fibroblasts expressing endogenous Pyk2 and in ID8 ovarian carcinoma cells expressing both Pyk2 and FAK. In both cell lines, Pyk2 knockdown increased p53 levels and inhibited cell proliferation associated with G(1) cell cycle arrest. Pyk2 FERM domain re-expression was sufficient to reduce p53 levels and promote increased BrdUrd incorporation. Pyk2 FERM promoted Mdm2-dependent p53 ubiquitination. Pyk2 FERM effects on p53 were blocked by proteasomal inhibition or mutational-inactivation of Pyk2 FERM nuclear localization. Staurosporine stress of ID8 cells promoted endogenous Pyk2 nuclear accumulation and enhanced Pyk2 binding to p53. Pyk2 knockdown potentiated ID8 cell death upon staurosporine addition. Moreover, Pyk2 FERM expression in human fibroblasts upon FAK knockdown prevented cisplatin-mediated apoptosis. Our studies demonstrate that nuclear Pyk2 functions to limit p53 levels, thus facilitating cell growth and survival in a kinase-independent manner.

Palatopharyngeal wall Perforation during Glidescope® Intubation

We report a case of palatopharyngeal wall perforation during intubation with a GlideScope® laryngoscope. The likely mechanism was advancing and rotating the endotracheal tube against a taut palatopharyngeal fold. This was missed during the initial laryngoscopy, because there is a potential blind-spot in the oropharynx when attention is focused on the GlideScope® monitor. Fortunately, there were no sequelae other than minor bleeding and a mild sore throat and no surgical intervention was necessary. The use of unnecessary force during the endotracheal tube insertion, the use of too large a laryngoscope blade and the use of a rigid stylet could possibly also have been contributory factors to this complication.

The ProSeal™ Laryngeal Mask Airway is an Effective Alternative to Laryngoscope-Guided Tracheal Intubation for Gynaecological Laparoscopy

We tested the hypothesis that the ProSeal™ laryngeal mask airway is superior to laryngoscope-guided tracheal intubation for gynaecological laparoscopy. One-hundred and eighty consecutive patients (ASA grade 1-2, aged 18-80y) were divided into two equal-sized groups for airway management with the ProSeal™ laryngeal mask airway or tracheal tube. Induction was with fentanyl/propofol, maintenance with sevoflurane and muscle relaxation with atracurium. The following primary variables were tested: time to achieve an effective airway, ventilatory capability, peak airway pressure before and after pneumoperitoneum, duration of surgery and pneumoperitoneum and haemodynamic responses. Data about gastric size, airway trauma and sore throat were collected. The number of attempts for successful insertion were similar, but effective airway time was shorter for the ProSeal™ laryngeal mask airway (20±2s vs 37±3s, P<0.001). All devices were successfully inserted within three attempts. There was no episode of failed ventilation or hypoxia. The haemodynamic stress responses to insertion and removal were greater for the tracheal tube than the ProSeal™ laryngeal mask airway. The duration of surgery, duration of pneumoperitoneum and intraabdominal pressures were similar. Gastric size was similar at the start and end of surgery. There were no differences in the frequency of complications or sore throat.

We conclude that the ProSeal™ laryngeal mask airway is a similarly effective airway device to conventional laryngoscope-guided tracheal intubation for gynaecological laparoscopy, but is more rapidly inserted and associated with an attenuated haemodynamic response to insertion and removal.

Video and optic laryngoscopy assisted tracheal intubation--the new era

With advances in technology, videoscopy and optic intubation have been gaining popularity particularly in patients with difficult airways or as rescue devices in failed intubation attempts. Their routine use is, however an uncommon occurrence. This review paper will summarise some of those newly developed devices currently available to assist tracheal intubation, their advantages, disadvantages when compared with the conventional laryngoscope and finally, evidence to support their use in both elective and emergency airway management.

Caspase-2-mediated cell death is required for deleting aneuploid cells

Caspase-2, one of the most evolutionarily conserved of the caspase family, has been implicated in maintenance of chromosomal stability and tumour suppression. Caspase-2 deficient (Casp2^−/−) mice develop normally but show premature ageing-related traits and when challenged by certain stressors, succumb to enhanced tumour development and aneuploidy. To test how caspase-2 protects against chromosomal instability, we utilized an ex vivo system for aneuploidy where primary splenocytes from Casp2^−/− mice were exposed to anti-mitotic drugs and followed up by live cell imaging. Our data show that caspase-2 is required for deleting mitotically aberrant cells. Acute silencing of caspase-2 in cultured human cells recapitulated these results. We further generated Casp2^C320S mutant mice to demonstrate that caspase-2 catalytic activity is essential for its function in limiting aneuploidy. Our results provide direct evidence that the apoptotic activity of caspase-2 is necessary for deleting cells with mitotic aberrations to limit aneuploidy.

Systemic and mucosal immune responses to rhesus rotavirus vaccine MMU 18006

Thirty-four children 3 to 20 months of age ingested either 10(5), 10(4) or 10(3) plaque-forming units of rhesus rotavirus vaccine, MMU 18006, which possesses human rotavirus serotype 3 neutralization antigen. Immune responses were evaluated by a plaque reduction neutralization (PRN) assay to rotavirus serotypes 1, 2 and 3 and by a serum IgG, IgM and IgA and fecal IgA class-specific enzyme-linked immunosorbent assay. Homotypic PRN antibody seroconversions to serotype 3 rotavirus were detected in 31 of 34 children (91%), whereas rises in heterotypic PRN antibody to human rotavirus serotypes 1 or 2 were found in only 3 of 21 (14%) (p less than 0.00000001). Thirty of the 34 vaccinated children (88%) had at least one class of rotavirus-specific serum antibody detected by enzyme-linked immunosorbent assay. A rotavirus-specific IgA coproantibody response was seen in 11 of 16 children (69%) following vaccination. Two children who had no evidence of PRN antibody to serotype 3 after vaccination had evidence of both a fecal and a serum rotavirus-specific IgA response, suggesting that in these children the response to the vaccine was primarily mucosal. These data show that orally administered rhesus rotavirus vaccine MMU 18006 elicits local intestinal immunity but produces primarily a homotypic serum neutralization response as measured by plaque reduction neutralization assays.

Regulation of inositol phospholipid binding and signaling through syndecan-4

Syndecan-4 is a transmembrane heparan sulfate proteoglycan that can regulate cell-matrix interactions and is enriched in focal adhesions. Its cytoplasmic domain contains a central region unlike that of any other vertebrate or invertebrate syndecan core protein with a cationic motif that binds inositol phospholipids. In turn, lipid binding stabilizes the syndecan in oligomeric form, with subsequent binding and activation of protein kinase C. The specificity of phospholipid binding and its potential regulation are investigated here. Highest affinity of the syndecan-4 cytoplasmic domain was seen with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5P)(2)) and phosphatidylinositol 4-phosphate, and both promoted syndecan-4 oligomerization. Affinity was much reduced for 3-phosphorylated inositides while no binding of diacylglycerol was detected. Syndecan-2 cytoplasmic domain had negligible affinity for any lipid examined. Inositol hexakisphosphate, but not inositol tetrakisphosphate, also had high affinity for the syndecan-4 cytoplasmic domain and could compete effectively with PtdIns(4,5)P(2). Since inositol hexaphosphate binding to syndecan-4 does not promote oligomer formation, it is a potential down-regulator of syndecan-4 signaling. Similarly, phosphorylation of serine 183 in syndecan-4 cytoplasmic domain reduced PtdIns(4,5)P(2) binding affinity by over 100-fold, although interaction could still be detected by nuclear magnetic resonance spectroscopy. Only protein kinase Calpha was up-regulated in activity by the combination of syndecan-4 and PtdIns(4,5)P(2), with all other isoforms tested showing minimal response. This is consistent with the codistribution of syndecan-4 with the alpha isoform of protein kinase C in focal adhesions.

Tumor necrosis factor-alpha stimulates focal adhesion kinase activity required for mitogen-activated kinase-associated interleukin 6 expression

Focal adhesion kinase (FAK) is a cytoplasmic protein-tyrosine kinase that promotes cell migration, survival, and gene expression. Here we show that FAK signaling is important for tumor necrosis factor-alpha (TNFalpha)-induced interleukin 6 (IL-6) mRNA and protein expression in breast (4T1), lung (A549), prostate (PC-3), and neural (NB-8) tumor cells by FAK short hairpin RNA knockdown and by comparisons of FAK-null (FAK(-/-)) and FAK(+/+) mouse embryo fibroblasts. FAK promoted TNFalpha-stimulated MAPK activation needed for maximal IL-6 production. FAK was not required for TNFalpha-mediated nuclear factor-kappaB or c-Jun N-terminal kinase activation. TNFalpha-stimulated FAK catalytic activation and IL-6 production were inhibited by FAK N-terminal but not FAK C-terminal domain overexpression. Analysis of FAK(-/-) fibroblasts stably reconstituted with wild type or various FAK point mutants showed that FAK catalytic activity, Tyr-397 phosphorylation, and the Pro-712/713 proline-rich region of FAK were required for TNFalpha-stimulated MAPK activation and IL-6 production. Constitutively activated MAPK kinase-1 (MEK1) expression in FAK(-/-) and A549 FAK short hairpin RNA-expressing cells rescued TNFalpha-stimulated IL-6 production. Inhibition of Src protein-tyrosine kinase activity or mutation of Src phosphorylation sites on FAK (Tyr-861 or Tyr-925) did not affect TNFalpha-stimulated IL-6 expression. Moreover, analyses of Src(-/-), Yes(-/-), and Fyn(-/-) fibroblasts showed that Src expression was inhibitory to TNFalpha-stimulated IL-6 production. These studies provide evidence for a novel Src-independent FAK to MAPK signaling pathway regulating IL-6 expression with potential importance to inflammation and tumor progression.