Diacylglycerol kinase alpha is a proliferation marker of intrahepatic cholangiocarcinoma associated with the prognosis.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) has a high recurrence rate and a poor prognosis. Thus, the development of effective treatment and prognostic biomarkers is required. High expression of diacylglycerol kinase alpha (DGKα) is a prognostic factor for the recurrence of hepatocellular carcinoma. However, the relationship between DGKα expression and prognosis in ICC has not been reported. METHODS: Immunohistochemistry (IHC) with anti-DGKα antibody was performed on surgical specimens of ICC (n = 69). First, DGKα expression in cancer cells was qualitatively classified into four groups (-, 1+, 2+, 3+) and divided into two groups (DGKα- and DGKα+1 + to 3+). The relationship between clinical features and DGKα expression was analyzed. Second, Ki-67 expression was evaluated as a cell proliferation marker. The number of Ki-67-positive cells was counted, and the relationship with DGKα expression was examined. RESULTS: DGKα IHC divided the patients into a DGKα+ group (1+: n = 15; 2+: n = 5; 3+: n = 5) and a DGKα- group (-: n = 44). In the DGKα+ group, patients were older and had advanced disease. Both overall survival and recurrence-free survival (RFS) were significantly worse in the DGKα+ patients. DGKα+ was identified as an independent prognostic factor for RFS by multivariate analysis. Furthermore, the number of Ki-67-positive cells increased in association with the staining levels of DGKα. CONCLUSION: Pathological DGKα expression in ICC was a cancer proliferation marker associated with recurrence. This suggests that DGKα may be a potential therapeutic target for ICC.

A very long chain fatty acid responsive transcription factor, MYB93, regulates lateral root development in Arabidopsis.

Lateral roots (LRs) are critical to root system architecture development in plants. Although the molecular mechanisms by which auxin regulates LR development have been extensively studied, several additional regulatory systems are hypothesized to be involved. Recently, the regulatory role of very long chain fatty acids (VLCFAs) has been shown in LR development. Our analysis showed that LTPG1 and LTPG2, transporters of VLCFAs, are specifically expressed in the developing LR primordium (LRP), while the number of LRs is reduced in the ltpg1/ltpg2 double mutant. Moreover, late LRP development was hindered when the VLCFA levels were reduced by the VLCFA synthesis enzyme mutant, kcs1-5. However, the details of the regulatory mechanisms of LR development controlled by VLCFAs remain unknown. In this study, we propose a novel method to analyze the LRP development stages with high temporal resolution using a deep neural network and identify a VLCFA-responsive transcription factor, MYB93, via transcriptome analysis of kcs1-5. MYB93 showed a carbon chain length-specific expression response following treatment of VLCFAs. Furthermore, myb93 transcriptome analysis suggested that MYB93 regulated the expression of cell wall organization genes. In addition, we also found that LTPG1 and LTPG2 are involved in LR development through the formation of root cap cuticle, which is different from transcriptional regulation by VLCFAs. Our results suggest that VLCFA is a regulator of LRP development through transcription factor-mediated regulation of gene expression and the transportation of VLCFAs is also involved in LR development through root cap cuticle formation.

Arginase-1 inhibition reduces migration ability and metastatic colonization of colon cancer cells.

BACKGROUND: Arginase-1 (ARG1), a urea cycle-related enzyme, catalyzes the hydrolysis of arginine to urea and ornithine, which regulates the proliferation, differentiation, and function of various cells. However, it is unclear whether ARG1 controls the progression and malignant alterations of colon cancer. METHODS: We established metastatic colonization mouse model and ARG1 overexpressing murine colon cancer CT26 cells to investigate whether activation of ARG1 was related to malignancy of colon cancer cells in vivo. Living cell numbers and migration ability of CT26 cells were evaluated in the presence of ARG inhibitor in vitro. RESULTS: Inhibition of arginase activity significantly suppressed the proliferation and migration ability of CT26 murine colon cancer cells in vitro. Overexpression of ARG1 in CT26 cells reduced intracellular L-arginine levels, enhanced cell migration, and promoted epithelial-mesenchymal transition. Metastatic colonization of CT26 cells in lung and liver tissues was significantly augmented by ARG1 overexpression in vivo. ARG1 gene expression was higher in the tumor tissues of liver metastasis than those of primary tumor, and arginase inhibition suppressed the migration ability of HCT116 human colon cancer cells. CONCLUSION: Activation of ARG1 is related to the migration ability and metastatic colonization of colon cancer cells, and blockade of this process may be a novel strategy for controlling cancer malignancy.

IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8+ T cells in vivo.

The induction of antitumor effector T cells in the tumor microenvironment is a crucial event for cancer immunotherapy. Neurokinin receptor 2 (NK2R), a G protein-coupled receptor for neurokinin A (NKA), regulates diverse physiological functions. However, the precise role of NKA-NK2R signaling in antitumor immunity is unclear. Here, we found that an IFN-γ-STAT1 cascade augmented NK2R expression in CD8+ T cells, and NK2R-mediated NKA signaling was involved in inducing antitumor effector T cells in vivo. The administration of a synthetic analog of double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C), into a liver cancer mouse model induced type I and type II IFNs and significantly suppressed the tumorigenesis of Hepa1-6 liver cancer cells in a STAT1-dependent manner. The reduction in tumor growth was diminished by the depletion of CD8+ T cells. IFN-γ stimulation significantly induced NK2R and tachykinin precursor 1 (encodes NKA) gene expression in CD8+ T cells. NKA stimulation combined with anti-CD3 monoclonal antibody (mAb) treatment significantly augmented IFN-γ and granzyme B production by CD8+ T cells compared with the anti-CD3 mAb alone in vitro. ERK1/2 phosphorylation and IκBα degradation in activated CD8+ T cells were suppressed under NK2R deficiency. Finally, we confirmed that tumor growth was significantly increased in NK2R-deficient mice compared with that in wild-type mice, and the antitumor effects of poly I:C were abolished by NK2R absence. These findings suggest that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector T cells in the tumor microenvironment, which contributes to the suppression of cancer cell tumorigenesis in vivo. In this study, we revealed that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8+ T cells in the tumor microenvironment, which contributes to suppressing the tumorigenesis of liver cancer cells in vivo.

Comparison of polymerization stresses of dental resin composites evaluated by two indentation fracture methods.

BACKGROUND: Polymerization stress is a major problem in dental resin composite restorations. Two indentation fracture methods can be applied to evaluate the stress, however, they often calculate different values. OBJECTIVE: To compare polymerization stresses of dental composites determined by the two methods. METHODS: Glass disks with a central hole were used. Two indentation fracture methods (Methods 1 and 2) were employed to determine the polymerization stresses of low-shrinkage and bulk-fill composites. Method 1: Cracks were made in the glass surface at 300 µm from the hole. The hole was filled with the composite. Polymerization stresses at 30 min after filling were calculated from the lengths of crack extension. Method 2: The hole was filled with the composite. Cracks were introduced in the glass at 1,000 µm from the hole at 30 min after the polymerization and the stresses were calculated from the crack lengths. Stresses at composite-glass bonded interface were calculated from the stress values obtained by the two methods. RESULTS: The bulk-fill composite generated the smallest interfacial stress, and Method 1 revealed lower values than Method 2. CONCLUSIONS: The composites yielded relatively small stresses. Method 1 calculated smaller stress values, possibly affected by the lower threshold stress intensity factor.

Changes of residual stresses on the surface of leucite-reinforced ceramic restoration luted with resin composite cements during aging in water.

The objective of this study was to compare the changes in the residual stresses present on the surface of leucite-reinforced dental ceramic restorations luted with a self-adhesive and a conventional resin composite cement during aging in water. Ring specimens made of a leucite-reinforced ceramics were luted to ceramic cylinders using a self-adhesive (Panavia SA Luting Plus) or a conventional resin composite cement (Panavia V5) in dual-cure or self-cure mode. Residual stresses on the ring surface were measured using indentation fracture method at 1 h, 1, 3, 7, 14 and 28 days of the 37 °C water immersion. Water sorption, water solubility and elastic modulus of the cements were also measured. Compressive stress was generated on the surface of the ceramic rings by the polymerization of the resin composite cements, and the stresses appeared to decrease over time by water sorption of the cements. The dual-cured conventional resin composite cement remained compressive stresses on the ceramic surface, while only the self-cured self-adhesive cement, which demonstrated the greatest water sorption, generated tensile stresses during the four weeks of aging in water. The elastic moduli of cements did not significantly change through the immersion, suggesting that the stresses were less affected by the modulus. To prevent the generation of tensile stresses on the leucite-reinforced ceramic restoration, self-adhesive cements exhibiting small water sorption should be clinically selected.

Residual polymerization stresses in human premolars generated with Class II composite restorations.

The objective of this study was to assess the influence of filling techniques on residual polymerization stresses in resin composite restorations of the tooth. Flat planes were ground in buccal enamel surfaces of extracted human premolars, followed by preparing Class II cavities. Indentation cracks were introduced in the planes and crack lengths were measured mesio-distally (x-direction) and cervico-incisally (y-direction). Cavities were filled with a resin composite and an adhesive using three methods; one with bulk filling and two with differing incremental filling techniques. The x- and y-tensile stresses were calculated from crack lengths measured repeatedly over 360 min after filling. Elastic modulus and polymerization shrinkage of the composite were also measured. Filling technique and time after fillings were statistically significant only for the y-stress. The incremental techniques generated smaller stresses than the bulk filling. The stresses developed for 60 min after filling, while the modulus and the shrinkage stopped developing within 10 min and 2 min after irradiation, respectively. The incremental technique, in which the proximal portion of the cavity was filled first, was effective in decreasing the residual tensile stress generated by the polymerization of resin composite.

Changes in polymerization stress and elastic modulus of bulk-fill resin composites for 24 hours after irradiation.

The objective of this study was to investigate changes in polymerization stress and elastic modulus for light-cured bulk-fill resin composites following irradiation. Crack analysis was applied to obtain the stresses for 24 h after irradiation, which were calculated from the lengths of cracks in a glass mold bonded to the composites. The elastic modulus was repeatedly measured by nano-indentation tests performed over 24 h. The lengths of the cracks, the interfacial stress, and the elastic modulus were significantly affected by the material and time after irradiation (p<0.01). The stress and elastic modulus continued to increase for more than 6 and 1 h, respectively (p<0.05). Strong relationships (r>0.85) were revealed between the stress and elastic modulus. The bulk-fill resin composites generated smaller stresses than a flowable resin composite reported to generate relatively low stress. Post-irradiation polymerization during the first 1 h is a major determinant for the magnitude of stress.

Creation of Customized Bioactivity within a 14-Membered Macrolide Scaffold: Design, Synthesis, and Biological Evaluation Using a Family-18 Chitinase.

Argifin, a 17-membered pentapeptide, inhibits chitinase. As argifin has properties that render it unsuitable as a drug development candidate, we devised a mechanism to create the structural component of argifin that bestows the chitinase inhibition and introduce it into a 14-membered macrolide scaffold. Here we describe (1) the designed macrolide, which exhibits ∼200-fold more potent chitinase inhibition than argifin, (2) the binding modes of the macrolide with Serratia marcescens chitinase B, and (3) the computed analysis explaining the reason for derivatives displaying increased inhibition compared to argifin, the macrolide aglycone displaying inhibition in a nanomolar range. This promises a class of chitinase inhibitors with novel skeletons, providing innovative insight for drug design and the use of macrolides as adaptable, flexible templates for use in drug discovery research and development.

Synthesis and verification of biobased terephthalic acid from furfural.

Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct. The dehydration of the DA adduct gave phthalic anhydride, which was converted via phthalic acid and dipotassium phthalate to TPA. The biobased carbon content of the TPA was measured by accelerator mass spectroscopy and the TPA was found to be made of 100% biobased carbon.

Predictors of hypofibrinogenemia in blunt trauma patients on admission.

PURPOSE: Massive bleeding usually leads to critically low levels of clotting factors, including fibrinogen. Although reduced fibrinogen levels correlate with increased mortality, predictors of hypofibrinogenemia have remained poorly understood. We investigated whether findings available on admission can be used as predictors of hypofibrinogenemia. METHODS: We retrospectively reviewed serum fibrinogen levels tested on arrival in 290 blunt trauma patients transported to a level I trauma center during a 3-year period. The primary outcome was prehospital predictors for hypofibrinogenemia. Covariates included age, sex, prehospital fluid therapy, prehospital anatomical and physiological scores, time from injury, base excess, and lactate on arrival. All variables with values of p < 0.10 in univariate analysis were included in a multivariate logistic regression model. The relationships between the variables and the 7-day mortality rate were evaluated in a Cox proportional hazards model. RESULTS: Patient's age [odds ratio (OR): 0.97, p < 0.001], Triage Revised Trauma Score (T-RTS) (OR: 0.81, p = 0.003), and prehospital fluid therapy (OR: 2.54, p = 0.01) were detected as independent predictors for hypofibrinogenemia in multivariate logistic regression analysis. Serum fibrinogen level [hazard ratio (HR): 0.99, p = 0.01] and T-RTS (HR: 0.77, p < 0.01) were associated with the 7-day mortality rate. CONCLUSION: T-RTS is considered to play an important role in predicting hypofibrinogenemia and 7-day mortality in blunt trauma patients.

Thermoresponsive copolymer brushes possessing quaternary amine groups for strong anion-exchange chromatographic matrices.

A thermoresponsive copolymer incorporating a quaternary amine group, poly(N-isopropylacrylamide-co-3-acrylamidopropyl trimethylammonium chloride (APTAC)-co-tert-butylacrylamide), was conjugated to the surface of silica beads through surface-initiated atom transfer radical polymerization. Prepared copolymer- and copolymer brush-modified beads were characterized by CHN elemental analysis, X-ray photoelectron spectroscopy, gel permeation chromatography, and observation of phase transition profiles. Phase transition profiles of the prepared copolymer indicated that 5 mol % APTAC is suitable for enabling thermally modulated property changes in the copolymer. Chromatographic elution behaviors of adenosine nucleotides and proteins were observed using prepared beads as chromatography matrices. Higher retention time of adenosine nucleotides and strong protein adsorption behavior were observed compared with those on beads with tertiary amine groups, because of the strong basic properties. Therefore, copolymer brush modified beads will be useful as thermoresponsive ion-exchange chromatographic matrices.

[Comparison of usefulness of the dorsal branch of the radial artery with the radial artery for arterial cannulation].

BACKGROUND: The radial artery cannulation is often associated with damped arterial waveforms with the hand moving. We used cannulation of the dorsal branch of the radial artery (DRA) and compared the stability of measurement, safety and complications with those of the radial artery(RA). METHODS: The study was a prospective single-blinded comparative study. Seventy-six patients undergoing general anesthesia requiring arterial cannulation were included. Patients were divided randomly into two separate groups of 35 patients each according to cannulation site: the radial artery (RA group) or the dorsal branch of the radial artery (DRA group). After induction of general anesthesia, cannulation was performed. Three hours after the successful cannulation, the changes of waveforms were noted with the hand moving. We examined whether there were any complications around the cannulation site after cannula removal. RESULTS: With the wrist flexion at all angles (30, 60 and 90 degrees), the frequency of worsening of arterial waveforms was significantly higher in RA group compared with DRA group. Some difficulties in catheter placement were observed in DRA group. No concomitant complication was noticed. CONCLUSIONS: Arterial line monitoring from DRA had better waveforms compared with RA monitoring without any complications.

Risk factors for gastric distension in patients with acute appendicitis: a retrospective cohort study.

PURPOSE: There has been no report on risk factors for gastric distension (GD) when inducing general anesthesia in an emergency situation. The aim of this study was to clarify the risk factors for GD in patients with acute appendicitis at their hospital visit. METHODS: We reviewed medical records of patients from April 2007 to March 2010 who underwent open appendectomy for acute appendicitis and were diagnosed pathologically. GD was defined as a larger anteroposterior diameter and larger lateral diameter of the stomach than those of the left kidney in computed tomography (CT) imaging. The primary outcome was the presence of GD. Candidate variables such as patient characteristics, physical findings, and CT imaging findings associated with GD were assessed. Time after beginning of abdominal pain was categorized and compared. Determinants with significant univariate association (P < 0.20) with the primary outcome were used to construct multivariable logistic regression models. RESULTS: We enrolled 121 patients and divided this cohort into a GD group (44 cases, 36%) and a non-GD group (77 cases, 64%). Results of univariate analysis showed longer duration of time after beginning of abdominal pain (P = 0.016), younger age (P < 0.001), and more frequent distended small bowel (P < 0.001) in the GD group than in the non-GD group. In multivariate analysis, age [odds ratio (OR) = 0.939, P = 0.002] and time after beginning of abdominal pain (OR = 1.807, P = 0.031) were shown to be independent risk factors. CONCLUSION: Younger appendicitis patients with acute abdominal pain for 1 or more days should be treated as patients with high risk for GD.

[Case of laryngeal edema occurring after tracheal extubation presumably due to antihypertensive medications].

A 61-year-old woman underwent microlaryngeal surgery for a vocal cord polyp. Anesthesia was induced with propofol, and vecuronium was given after loss of consciousness. The trachea was intubated smoothly with a Portex tracheal tube with a 6.0 mm in inner diameter and the cuff was inflated to the minimal occlusion volume. Anesthesia was maintained with O2-air-sevoflurane. The surgical procedure was completed without any troubles. Immediately after tracheal extubation, she developed dyspnea with stridor. As marked laryngeal edema was found by direct vision with the aide of a laryngoscope, reintubation was performed and methylprednisolone was administered intravenously. She was extubated on the next day, after confirmation of the tracheal tube cuff leak following the reduction in the cuff pressure. At this time, fiberoptic bronchoscopy revealed that the laryngeal edema had disappeared. For the past history, she had taken amlodipine for 10 years and candesertan for 2 months, and had often experienced dyspnea. It should be kept in mind that preoperative antihypertensive medications might have an impact on occurrence of perioperative laryngeal edema.

Differential effects of propofol and sevoflurane on ischemia-induced ventricular arrhythmias and phosphorylated connexin 43 protein in rats.

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.

Cardioprotective effects of propofol in isolated ischemia-reperfused guinea pig hearts: role of KATP channels and GSK-3beta.

PURPOSE: Propofol exerts cardioprotective effects, but the involved mechanisms remain obscure. The present study examines the cardioprotective effects of propofol and its role in cardiac function, including its effect on K(ATP) channel opening and the inhibition of GSK-3beta activity in ischemia-reperfused hearts. METHODS: Ischemia-reperfusion (I/R) was produced in isolated guinea pig hearts by stopping coronary perfusion for 25 min, followed by reperfusion. The hearts were incubated for ten minutes, with or without propofol (25 or 50 microM), or for five minutes with 500 microM 5-hydroxydecanoate (a mitochondrial K(ATP) channel blocker) or 30 microM HMR1098 (sarcolemmal K(ATP) channel blocker), followed by five minutes with 50 microM propofol before ischemia. Action potentials on the anterior epicardial surface of the ventricle were monitored using a high-resolution charge-coupled device camera system, and at five minutes after reperfusion, GSK-3beta phosphorylation at the serine residue, Ser9, was examined. RESULTS: After 35 min of reperfusion, propofol (25 and 50 microM) blunted the adverse effects of I/R and reduced infarct size (P < 0.05). In addition, prior incubation with 5-hydroxydecanoate or HMR1098 had no effect on functional recovery improved by 50 microM propofol. At five minutes after reperfusion, propofol (25 and 50 microM) shortened the duration of the action potential and increased the levels of phospho-GSK-3beta (P < 0.05). CONCLUSIONS: Propofol enhanced mechanical cardiac recovery and reduced infarct size. The data further suggest that GSK-3beta play an important role in propofol cardioprotective actions during coronary reperfusion, but mitochondrial K(ATP) channels do not.

Efficacy of abdominal computed tomography and nasogastric tube in acute poisoning patients.

Abdominal computed tomography aids in the evaluation of the conditions in the stomach and will decrease needless gastric lavage in acute poisoning patients. A 16-year-old girl with a history of schizophrenia with depressive disorder was taken to our hospital. Her Glasgow Coma Scale was 8. Symptoms related to anticholinergic effects were strongly present. Her electrocardiogram showed sinus tachycardia with 60 milliseconds of QRS duration. Computed tomography images showed that the patient had a large amount of debris derived from tablets in her stomach and duodenum. We performed gastric aspiration through a nasogastric tube and not gastric lavage, and it took 5 minutes to complete the procedure. We administered activated charcoal 3 times. Intubation was not performed. Other than tonic-clonic seizure that was observed once, neither cardiovascular nor neurologic symptoms were observed. She recovered fully and admitted that she had ingested more than a hundred tablets almost 10 hours before being brought to our hospital. Computed tomography images show a cluster of tablets and debris to be of a higher density than tissues; this allows quantitative and qualitative evaluations to be performed. We were able to treat the patient with effective use of nasogastric tube.

Severe hyperglycemic shock associated with hepatic portal venous gas.

We report a case of hyperglycemic shock associated with hepatic portal venous gas. A 79-year-old woman with post-stroke depression developed severe tachycardiac atrial fibrillation and hypotension due to hypovolemia caused by severe hyperglycemia, as well as showing disseminated intravascular coagulation (DIC). Continuous intravenous infusion of insulin and volume loading with normal saline gradually achieved normalization of the serum glucose level and hemodynamic stability. However, the DIC did not resolve, and abdominal computed tomography (CT) revealed hepatic portal venous gas (HPVG) in the left lobe of the liver. Surgery was thus considered mandatory. However, because severe hemodynamic lability occurred again immediately after the CT examination, and persisted, surgery could not be performed, and the patient died of septic shock due to bowel perforation. It was concluded that the underlying causes of DIC should be sought promptly, without delay.

Anesthetic management of two cases of Beckwith-Wiedemann syndrome.

Two cases of children with Beckwith-Wiedemann syndrome are presented. This syndrome consists of various abnormalities, including macroglossia, visceromegaly, omphalocele, and gigantism. These abnormalities frequently require operative correction during the neonatal period. We anesthesiologists should make plans for difficult airway managements in patients with this syndrome. Our two patients also showed larger sized tracheas than those estimated by their age and height. A cuffed tube, though still controversial, has recently been used in children. We recommend using a cuffed tube in patients with this syndrome, because the appropriate tracheal size may not be predictable, tracheal intubation might be difficult, and risks incurred during changing of a tracheal tube should be avoided.