Effects of using the simplified airway risk index vs usual airway assessment on unanticipated difficult tracheal intubation - a cluster randomized trial with 64,273 participants.

BACKGROUND: Unanticipated difficult intubation remains a challenge in anaesthesia. The Simplified Airway Risk Index (SARI) is a multivariable risk model consisting of seven independent risk factors for difficult intubation. Our aim was to compare preoperative airway assessment based on the SARI with usual airway assessment. METHODS: From 01.10.2012 to 31.12.2013, 28 departments were cluster-randomized to apply the SARI model or usual airway assessment. The SARI group implemented the SARI model. The Non-SARI group continued usual airway assessment, thus reflecting a group of anaesthetists' heterogeneous individual airway assessments. Preoperative prediction of difficult intubation and actual intubation difficulties were registered in the Danish Anaesthesia Database for both groups. Patients who were preoperatively scheduled for intubation by advanced techniques (e.g. video laryngoscopy; flexible optic scope) were excluded from the primary analysis. Primary outcomes were the proportions of unanticipated difficult and unanticipated easy intubation. RESULTS: A total of 26 departments (15 SARI and 11 Non-SARI) and 64 273 participants were included. In the primary analyses 29 209 SARI and 30 305 Non-SARI participants were included.In SARI departments 2.4% (696) of the participants had an unanticipated difficult intubation vs 2.4% (723) in Non-SARI departments. Odds ratio (OR) adjusted for design variables was 1.03 (95% CI: 0.77-1.38). The proportion of unanticipated easy intubation was 1.42% (415) in SARI departments vs 1.00% (302) in Non-SARI departments. Adjusted OR was 1.26 (0.68-2.34). CONCLUSIONS: Using the SARI compared with usual airway assessment we detected no statistical significant changes in unanticipated difficult- or easy intubations. CLINICAL TRIAL REGISTRATION: NCT01718561.

Tracheal intubation in patients with anticipated difficult airway using Boedeker intubation forceps and McGrath videolaryngoscope.

BACKGROUND: Videolaryngoscopes with sharp angulated blades improve the view of the vocal cords but this does not necessarily result in higher success rates of intubation The aim of this study was to evaluate the efficacy of using Boedeker intubation forceps in conjunction with McGrath Series 5 Videolaryngoscope (MVL) in patients with predictors for difficult intubation. METHODS: The study was conducted at the Department of Anaesthesia, Copenhagen University Hospital from September to December 2013. Patients with one or more predictors of difficult intubation scheduled for general anaesthesia were assessed for eligibility. Patients were intubated using Boedeker intubation forceps and MVL. The primary endpoint was time to intubation. The secondary endpoints were intubation success rate, number of intubation attempts, intubation conditions and post-operative hoarseness. RESULTS: Thirty-three patients were assessed for eligibility, and 25 patients were included in the study with a median SARI score of 3 (IQR 3-4). Twenty-two (88%, 95% confidence interval [74-100%]) of the patients were successfully intubated by the method with a median time to intubation of 115 s (IQR 78-247). Steering and advancement of the tube were reported as acceptable in 21 (84%) and 22 cases (88%), respectively, and excellent in 10 cases (45%) for both measures. Ten cases (40%) were intubated on the first attempt. There were three cases (12%) of failed intubation; in these cases, successful intubation was obtained by using a styletted tube. CONCLUSION(S): Most patients with anticipated difficult intubation can be successfully intubated with Boedeker intubation forceps and MVL. However, endotracheal tube placement failed in 3/25 patients despite a good laryngeal view.

Laryngeal morbidity after tracheal intubation: the Endoflex(®) tube compared to conventional endotracheal intubation with stylet.

BACKGROUND: Tracheal intubation may cause vocal fold damage. The trial was designed to assess laryngeal morbidity comparing the Endoflex(®) tube with a conventional endotracheal tube with stylet. We hypothesised that laryngeal morbidity within the first 24 h after extubation would be lower with the Endoflex tube than with the conventional endotracheal tube with stylet because of less rigidity. METHODS: This randomised trial included 130 elective surgical patients scheduled for general anaesthesia with endotracheal intubation. Pre- and post-operative assessment of hoarseness, vocal fold pathology, and voice analysis using the Multidimensional Voice Program was performed. Induction of anaesthesia was standardised. After complete neuromuscular paralysis, intubation was done with an Endoflex tube or a conventional endotracheal tube with stylet. RESULTS: Post-operative hoarseness was found in 45% with the Endoflex tube and 55% with the endotracheal tube with stylet at 24 h after extubation (P = 0.44). Post-operative vocal fold injury was present in 23% in the Endoflex tube group and in 36% in the endotracheal tube with stylet group (P = 0.13). The increase in shimmer, the voice analysis variable reflecting vocal fold oedema, was 0.5% in the Endoflex tube group and 2.5% in the endotracheal tube with stylet group (P = 0.02). CONCLUSION: No significant difference was found in the incidence of hoarseness or vocal fold injury using the Endoflex tube. However, the statistically significant lower increase in the shimmer values in that group implies that the Endoflex may be associated with less laryngeal morbidity.

Wound-induced apoplastic peroxidase activities: their roles in the production and detoxification of reactive oxygen species.

Production of reactive oxygen species (ROS) is a widely reported response of plants to wounding. However, the nature of enzymes responsible for ROS production and metabolism in the apoplast is still an open question. We identified and characterized the proteins responsible for the wound-induced production and detoxification of ROS in the apoplast of wheat roots (Triticum aestivum L.). Compared to intact roots, excised roots and leachates derived from them produced twice the amount of superoxide (O2(*-)). Wounding also induced extracellular peroxidase (ECPOX) activity mainly caused by the release of soluble peroxidases with molecular masses of 37, 40 and 136 kD. Peptide mass analysis by electrospray ionization-quadrupole time-of-flight-tandem mass spectrometry (ESI-QTOF-MS/MS) following lectin affinity chromatography of leachates showed the presence of peroxidases in unbound (37 kD) and bound (40 kD) fractions. High sensitivity of O2(*-)-producing activity to peroxidase inhibitors and production of O2(*-) by purified peroxidases in vitro provided evidence for the involvement of ECPOXs in O2(*-) production in the apoplast. Our results present new insights into the rapid response of roots to wounding. An important component of this response is mediated by peroxidases that are released from the cell surface into the apoplast where they can display both oxidative and peroxidative activities.

How does auxin enhance cell elongation? Roles of auxin-binding proteins and potassium channels in growth control.

Elongation growth and a several other phenomena in plant development are controlled by the plant hormone auxin. A number of recent discoveries shed light on one of the classical problems of plant physiology: the perception of the auxin signal. Two types of auxin receptors are currently known: the AFB/TIR family of F box proteins and ABP1. ABP1 appears to control membrane transport processes (H+ secretion, osmotic adjustment) while the TIR/AFBs have a role in auxin-induced gene expression. Models are proposed to explain how membrane transport (e.g., K+ and H+ fluxes) can act as a cross-linker for the control of more complex auxin responses such as the classical stimulation of cell elongation.

Phylloquinone, what can we learn from plants?

The plant plasma membrane contains redox proteins able to mediate a trans-membrane electron flow. This electron flow might be responsible for the generation of the active oxygen species observed as a reaction to pathogen attack or stress. Vitamin K1 could be identified as a possible lipid soluble electron carrier in plant plasma membrane preparations. Such a function would be analogous to coenzyme Q in animal plasma membranes. What we are going to outline in this contribution is a concept of how the electron transport system of the plant plasma membrane could interact with quinones, thus contributing to the metabolism of free radicals in plants.

Interaction between electron transport at the plasma membrane and nitrate uptake by maize (Zea mays L.) roots.

In the present study nitrate uptake by maize (Zea mays L.) roots was investigated in the presence or absence of ferricyanide (hexacyanoferrate III) or dicumarol. Nitrate uptake caused an alkalization of the medium. Nitrate uptake of intact maize seedlings was inhibited by ferricyanide while the effect of dicumarol was not very pronounced. Nitrite was not detected in the incubation medium, neither with dicumarol-treated nor with control plants after application of 100 microM nitrate to the incubation solution. In a second set of experiments interactions between nitrate and ferricyanide were investigated in vivo and in vitro. Nitrate (1 or 3 mM) did neither influence ferricyanide reductase activity of intact maize roots nor NADH-ferricyanide oxidoreductase activity of isolated plasma membranes. Nitrate reductase activity of plasma-membrane-enriched fractions was slightly stimulated by 25 microM dicumarol but was not altered by 100 microM dicumarol, while NADH-ferricyanide oxidoreductase activity was inhibited in the presence of dicumarol. These data suggest that plasma-membrane-bound standard-ferricyanide reductase and nitrate reductase activities of maize roots may be different. A possible regulation of nitrate uptake by plasmalemma redox activity, as proposed by other groups, is discussed.

MR-guided laser-induced thermotherapy in recurrent extrahepatic abdominal tumors.

The aim of this study was to evaluate the feasibility of MR-guided laser-induced thermotherapy (LITT) for treatment of recurrent extrahepatic abdominal tumors. In 11 patients (6 women and 5 men; mean age 53 years, age range 29-67 years) with 14 lesions the following tumors were treated in this study: paravertebral recurrence of hypernephroma (n=1); recurrence of uterus carcinoma (n=1); recurrence of chondrosarcoma of the pubic bone (n=1); presacral recurrence of rectal carcinoma (n=1); recurrent anal cancer (n=1); metastases in the abdominal wall (n=1); and lymph node metastases from colorectal cancer (n=8). A total of 27 laser applications were performed. A fast low-angle shot 2D sequence (TR/TE/flip angle=102 ms/8 ms/70 degrees ) was used for nearly real-time monitoring during treatment. All patients had no other treatment option. Seventeen LITT sessions were performed using a conventional laser system with a mean laser power of 5.2 W (range 4.5-5.7 W), and 10 LITT session were performed using a power laser system with a mean laser power of 28.0 W. In 10 lesions total destruction could be achieved. In the remaining recurrent tumors, significant reduction of tumor volume by 60-80% was obtained. All patients tolerated the procedure well under local anesthesia. No complications occurred during treatment. Laser-induced thermotherapy is a practicable, minimally invasive, well-tolerated technique that can produce large areas of necrosis within recurrent tumors, substantially reducing active tumor volume if not resulting in outright destruction of tumor.

The auxin signal for protoplast swelling is perceived by extracellular ABP1.

Protoplasts of corn coleoptiles and Arabidopsis hypocotyls respond to the plant hormone auxin with a rapid change in volume. We checked the effect of antibodies directed against epitopes of auxin-binding protein 1 from Arabidopsis thaliana (AtERabp1) and Zea mays (ZmERabp1), respectively. Antibodies raised against the C-terminus of AtERabp1 inhibited the response to auxin, while antibodies raised against a part of box a, the putative auxin-binding domain, induced a swelling response similar to that caused by auxin treatment. Synthetic C-terminal oligopeptides of ZmERabp1 also caused a swelling response. These effects occurred regardless of whether the experiments were carried out with homologous (anti-AtERabp1 antibodies on Arabidopsis protoplasts or anti-ZmERabp1 antibodies in maize protoplasts) or heterologous immunological tools. The results indicate that the auxin signal for protoplast swelling is perceived by extracellular ABP1.

Percutaneous MR imaging-guided laser-induced thermotherapy of hepatic metastases.

BACKGROUND: Many primary tumors may cause liver metastases, which are generally treated with surgical resection and/or chemotherapy. After resection of liver metastases in patients with colorectal carcinoma, 5-year survival rates are achieved in 25-38%, and two-thirds of patients will experience recurrent metastases. We examined percutaneous, minimally invasive, laser-induced thermotherapy (LITT) as an alternative outpatient procedure. Local tumor control rate and survival data were analyzed prospectively. METHODS: Between June 1993 and August 2000, 7148 laser applications were performed in 1981 lesions in 705 consecutive patients and 1653 treatment sessions. The complications of the procedure were evaluated by clinical examination and magnetic resonance imaging (MRI) and computed tomography. Local tumor control was evaluated by plain and contrast-enhanced follow-up MRI using T1- and T2-weighted spin-echo and gradient-echo sequences every 3 months after treatment. Cumulative survival times were calculated using the Kaplan-Meier method. RESULTS: The overall rate of complications and side effects was 7.5%. The rate of clinically relevant complications was 1.3%. Local tumor control rate after 3 months was 99.3%; 6 months after laser treatment, plain and contrast-enhanced MRI documented a local tumor control rate of 97.9%. In patients treated with MR-guided LITT for unresectable colorectal liver metastases, the mean survival was 41.8 months (95% confidence interval = 37.3-46.4 months). The 1-year survival rate was 93%, the 2-year survival rate was 74%, the 3-year survival rate was 50%, and the 5-year survival was 30%. In patients treated with LITT for liver metastases from breast cancer, the mean survival was 4.3 years (95% confidence interval = 3.6-5.0 years). CONCLUSION: In patients with liver metastases, local tumor destruction using minimally invasive, percutaneous LITT under local anesthesia results in improved clinical outcomes and survival rates and can be a potential alternative to surgical resection.

Laser-induced thermotherapy of malignant liver tumors: general principals, equipment(s), procedure(s)--side effects, complications and results.

PURPOSE: To prospectively evaluate the therapeutic potential of MR-guided and ultrasound-guided laser-induced thermotherapy (LITT) in patients with liver metastases and oligonodular hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Between June 1993 and June 2000 a total of 1608 LITT sessions was performed to treat 1914 lesions in 676 consecutive patients. The Nd-YAG laser fiber was introduced with a percutaneously positioned cooled application set. Qualitative and quantitative ultrasound and magnetic resonance (MR) parameters, as well as clinical data were evaluated. RESULTS: All patients tolerated the procedure well under local anesthesia; no relevant clinical complications were observed. The mean laser power was 25 W and the mean duration was 25 min. MR proved to be superior over computed tomography and ultrasound due the thermosensitivity of the MR sequences allowing a better visualization of the volume of laser-induced changes and their relation to the neighboring geographical structures. The ultrasound-guided LITT should be restricted for patients with contraindications for MR imaging monitoring and for selected patients with low diameter oligonodular HCC. In 95% of cases, we achieved a complete necrosis of the tumor and a 5-mm safety margin, resulting in a complete destruction of the tumor without local recurrences. Mean survival in this group was 35 months (calculated with the Kaplan-Meier method). CONCLUSION: MR-guided, or ultrasound-guided, LITT appears to be a safe and effective treatment protocol for liver metastases and oligonodular HCC.

Structure of transfection-active histone H1/DNA complexes.

Relationships between the structure of transfecting complexes of histone H1 and DNA and their transfection efficiency were studied. Transfection activity proved to be connected to complex aggregates. Low speed centrifugation of the complexes resulted in loss of the transfection activity. The complexes/aggregates were active with high efficiency in a broad range of weight input ratios r(i) (0.1 < r(i) < 30). Using atomic force microscopy (AFM), the complexes were imaged at negative, nearly electroneutral and positive charge conditions. Electroneutral complexes at r(i) = 1 showed a multitude of different complex forms. Fibrillar, network-like and branched structures were frequently present in one complex. Strongly positive charged complexes had a toroidal appearance. All these different forms contributed to the high transfection efficiency. Cellular uptake is supposed to be by phagocytosis.

Histone H1-mediated transfection: serum inhibition can be overcome by Ca2+ ions.

PURPOSE: One of the drawbacks of polycationic and cationic liposomal gene transfer is its sensitivity to serum. Gene therapy requires the transfectant-DNA complex to be resistant to serum as well as blood. Since Ca2+ has proved to be an efficient cofactor of polycationic gene transfer, we decided to investigate its effects on transfection in the presence of serum. METHODS: We studied transgene expression of luciferase gene (pCMV Luc) on ECV 304 human endothelial cells using H1 histone and DOSPER as transfectants in the presence of 0-100% fetal calf serum. RESULTS: H1-and DOSPER-mediated transfection was found to be inhibited by serum above the concentration of 10%. If 2 mM Ca2+ or 2 mM Ca2+/0.1 mM chloroquine was included in the culture medium which replace the transfection mixture and was left on the cells for 24 hours postincubation, the inhibiting effect of even 100% serum was overcome. CONCLUSIONS: A high serum level does not interfere with binding and uptake of H1- and DOSPER-DNA complexes, but inhibits subsequent steps such as endosomal escape. Ca2+ in the form of nascent calcium phosphate microprecipitates and other lysosomolytical agents facilitate endosomal/lysosomal release by their fusigenic and membranolytic activity.

Immunocytochemical visualization of transfected DNA in cultured cells.

Nonviral transfection is one of the modern methods for the incorporation of foreign genes into cells. This process involves uptake of foreign genetic material by the cell and further trafficking through the cytoplasm to the nucleus. Elucidation of cytoplasmic pathways of transfection complexes can be useful to improve already existing gene delivery systems or to establish new systems. To monitor transfection complexes in the cell during transfection, we elaborated a method for the visualization of transfection complexes by introducing digoxigenin-labelled nucleotides into foreign DNA followed by detection of digoxigenin label with the use of antibodies directed against digoxigenin. This procedure allowed the visualization of DNA in transfection complexes and to monitor these complexes in cells during transfection.

Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism.

Auxin-induced growth of coleoptiles depends on the presence of potassium and is suppressed by K+ channel blockers. To evaluate the role of K+ channels in auxin-mediated growth, we isolated and functionally expressed ZMK1 and ZMK2 (Zea mays K+ channel 1 and 2), two potassium channels from maize coleoptiles. In growth experiments, the time course of auxin-induced expression of ZMK1 coincided with the kinetics of coleoptile elongation. Upon gravistimulation of maize seedlings, ZMK1 expression followed the gravitropic-induced auxin redistribution. K+ channel expression increased even before a bending of the coleoptile was observed. The transcript level of ZMK2, expressed in vascular tissue, was not affected by auxin. In patch-clamp studies on coleoptile protoplasts, auxin increased K+ channel density while leaving channel properties unaffected. Thus, we conclude that coleoptile growth depends on the transcriptional up-regulation of ZMK1, an inwardly rectifying K+ channel expressed in the nonvascular tissue of this organ.

Calcium ions as efficient cofactor of polycation-mediated gene transfer.

We investigated the effect of calcium on the transfection of non-viral DNA transfer systems. Cationic proteins such as the nuclear protein H1, the polycation polylysine and a number of commercial transfection agents exhibited high transfection rates in the presence of Ca2+. Without Ca2+ H1 and HMG1 were inactive in transfection of the human permanent endothelial cell line ECV 304 while cationic liposomes such as Lipofectin and Lipofectamine did not show any Ca2+ dependence. More detailed experiments showed that Ca2+ was replaceable by the lysosomotropic agent chloroquine. Furthermore, it was possible to separate the transfection-enhancing role of Ca2+ from the actual transfection process by adding Ca2+ to the cells after the transfection period and still to obtain a significant transgene expression. This makes it possible to distinguish between cellular uptake of H1 (or mediator)-DNA complexes and endocytotic release. We also replaced soluble Ca2+ by Ca-phosphate precipitates not containing DNA and obtained similar transfection results. This allowed us to suggest that the addition of free Ca2+ to the transfection medium resulted in nascent Ca-phosphate microprecipitates. The known fusogenic and membranolytic activity of such microprecipitates could facilitate the transport through and the release of the transfecting complexes from the endosomal/lysosomal compartment.

Ligand-histone H1 conjugates: increased solubility of DNA complexes, but no enhanced transfection activity.

We introduced galactose and a short RGD sequence as ligands into H1 histone to target the asialoglycoprotein receptor or integrins on cells expressing these receptors. The efficiency of the gene transfer mediated by galactosylated H1 histone was strongly affected by the transfection conditions. Galactosylation of H1 led to an increase of the basic H1-mediated gene transfer activity only, when H1 itself did not develop its optimal transfection activity. Under other conditions any specific gene transfer mediated by the asialoglycoprotein receptor was covered by the high transfection efficiency of H1 itself. Similar results of a marginal increase in the transfection efficiency were obtained by conjugates of a short RGD sequence and H1. This unexpected failure in the receptor specificity of both conjugates could be due to the unspecific cell-binding capacity of the H1 moiety and to increasing solubility of the complexes as shown by gel shift and solubility measurements.

Polycation-mediated transfection: how to overcome undesirable side effects of sticky DNA complexes.

Using polycationic transfection one encounters undesired persistent binding to cells of sticky polycation/DNA complexes. These complexes simulate transfection under conditions where no uptake is expected e.g. at 4 degrees C if the uptake is by endocytosis. To overcome this problem, using H1/DNA complexes, we developed an easy and nontoxic method for removing the sticky complexes not taken up during the transfection phase. The cells are simply washed with isotonic (0.1 M) MgCl2 solution, which enables the complete removal of the complexes by their rapid dissolution.