Effects of hCRH on sleep and body temperature rhythms

We investigated the effects of human corticotropin-releasing hormone (hCRH) on the sleep structure and body temperature rhythms of seven healthy young men. Polysomnographic recordings were obtained and body temperatures were monitored continuously for 48 h in each subject following the intravenous administration of saline or of 100 micrograms hCRH. The administration of hCRH was associated with a significant phase-advancement in body temperature rhythm vs the saline control. The administration of hCRH affected non-rapid eye movement (NREM) sleep by reducing significantly slow wave sleep (SWS) and sleep efficiency, whereas the percentage of sleep stages 1 and 2 were increased significantly. These changes in body temperature rhythms and sleep structure induced by hCRH resembled those observed in patients with endogenous depression, except for the findings during rapid eye movement (REM) sleep. We hypothesize that a hypersecretion of hCRH in patients with endogenous depression may help to explain the changes in body temperature rhythms and sleep structure often reported in such patients.

Bystander effect caused by suicide gene expression indicates the feasibility of gene therapy for hepatocellular carcinoma

In the field of gene therapy using retroviral vectors, it appears impossible to introduce a foreign gene into all target cells. Therefore adjacent cell killing, the socalled bystander effect, caused by genetically modified cells provides therapeutic advantages for gene therapy against cancers. We retrovirally transduced the herpes simplex virus thymidine kinase (HSV-tk) gene into murine and rat hepatocellular carcinoma (HCC) cells. These HSV-tk gene-transduced HCC cells were cocultured with the corresponding parental cells in the presence of ganciclovir, at a concentration not at all cytotoxic to the parental cells. When parental HCC cells were cocultured with their HSV-tk gene-transduced counterparts at a high density at which most cells were in contact with one another, they were markedly eliminated. Conversely, when cocultured at a low density at which none of the cells were in contact, a weak but statistically significant bystander effect was observed. Addition of lysates of HSV-tk gene-transduced cells in the presence of ganciclovir did not cause and killing of parental cells. Furthermore, media conditioned by transduced cells with ganciclovir exhibited weak cytotoxic effects on parental cells. These results indicate that cell-cell contact plays a major causative role in the bystander effect and that minor contributors to this phenomenon are some cytotoxic substance released from transduced cells. Importantly, the bystander effect was induced in vivo as well as in vitro. When mixtures of transduced and untransduced HCC cells were implanted into the flank region of mice, intraperitoneal ganciclovir administration considerably inhibited tumor development, indicating the feasibility of gene therapy with HSV-tk gene and ganciclovir against HCC.

Monoclonal antibody against the polymorphic site distinguishes apolipoprotein E4 from other isoforms

Apolipoprotein E4 has been confirmed as a genetic risk factor for Alzheimer's disease. Although several hypotheses have been advanced to explain how the inheritance of apolipoprotein E isoforms affects the rate of Alzheimer's disease expression, the mechanism whereby apolipoprotein E is involved in the pathogenesis of Alzheimer's disease is still uncertain. To clarify the way in which the apolipoprotein E4 isoform differs from the others, we generated a monoclonal antibody specifically reactive with the apolipoprotein E4 isoform. This antibody suggests that the polymorphic site is important in differentiating the ApoE4 isoform from others.

Serial changes of plasma plasminogen activator inhibitor activity in acute myocardial infarction: difference between thrombolytic therapy and direct coronary angioplasty

The fibrinolytic system is impaired in patients with acute myocardial infarction (AMI). The primary regulatory element of fibrinolytic activity is plasminogen activator inhibitor (PAI). There are no reports, however, on the serial changes of PAI activity after thrombolysis or coronary angioplasty in patients with AMI undergoing emergency coronary angiography. This study was designed to examine the difference in the change of fibrinolytic activity between patients with AMI who underwent thrombolytic therapy with recombinant tissue-plasminogen activator (rTPA) and those who underwent direct percutaneous coronary angioplasty (PTCA). We measured the serial changes of PAI activity and tissue plasminogen activator (TPA) antigen after rTPA therapy or direct PTCA. Twenty-two patients received emergency coronary angiography and were treated with rTPA intravenously. Twenty patients underwent direct PTCA. Plasma PAI activity levels were increased on admission and further increased within 24 hours in patients treated with rTPA and in those treated with direct PTCA. In the thrombolysis group, there were two peaks in plasma PAI activity levels (IU/ml) at 4 hours (27.0 +/- 2.9) and at 16 hours (25.6 +/- 2.5) after the initiation of rTPA infusion. However, in the direct PTCA group, there was one peak of PAI activity (IU/ml) at 16 hours (23.9 +/- 2.7) after the initiation of direct PTCA. In conclusion, the PAI activity has two peaks in the thrombolysis group and one peak in the direct PTCA group.

Down-regulation of bcl-xs gene expression in rat thymocytes by dexamethasone

In order to test a hypothesis that the expression of bcl-x gene promotes apoptosis by antagonizing the function of bcl-2 gene product, time course of the expression of bcl-x was investigated using the dexamethasone-treated rat thymocytes which were undergoing apoptosis. Unexpectedly, dexamethasone suppressed the expression of bcl-x in a dose- and time-dependent manner. Such decrease was detected even in the presence of cycloheximide, suggesting that the suppression is due to the genomic (primary) effect of dexamethasone. Since the expression of bcl-xL, as measured by a specific nucleotide probe, was not detected at a quantifiable level, the decrease was apparently attributed to that in bcl-xS. Our present observations propose a new role of the bcl-xS gene product, in which the bcl-x gene product may be necessary for survival of immature thymocytes rather than for their apoptosis.

Soluble P-selectin is released into the coronary circulation after coronary spasm

BACKGROUND

The glycoprotein P-selectin is an adhesion molecule involved in the property change of leukocytes at the initiation of the inflammatory process. The purpose of the present study was to determine whether acute myocardial ischemia induced by coronary spasm causes an acute inflammatory response in the coronary circulation.

METHODS AND RESULTS

We examined plasma soluble P-selectin levels in the coronary sinus and the aortic root simultaneously in 16 patients with coronary spastic angina before and after left coronary artery spasm induced by intracoronary injection of acetylcholine and in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. Ten control patients with chest pain but normal coronary arteries and no coronary spasm also received intracoronary acetylcholine. Plasma soluble P-selectin levels were increased significantly in the coronary sinus (32.8 +/- 3.6 to 52.8 +/- 5.9 ng/mL, P < .001) and in the aortic root (34.6 +/- 3.7 to 41.9 +/- 4.4 ng/mL, P < .05) after the attacks in the coronary spastic angina group but remained unchanged in the stable exertional angina group after the attacks and in the control group after the administration of acetylcholine. Furthermore, the coronary sinus-arterial difference of soluble P-selectin increased significantly after the attacks in the coronary spastic angina group (-1.8 +/- 2.2 to 10.9 +/- 2.7 ng/mL, P < .001).

CONCLUSIONS

Our data indicate that soluble P-selectin is released into the coronary circulation after coronary artery spasm. We conclude that coronary artery spasm may induce the leukocyte adhesion in the coronary circulation and may lead to myocardial damage.

Identification of a new susceptibility locus for insulin-dependent diabetes mellitus by ancestral haplotype congenic mapping

The number and exact locations of the major histocompatibility complex (MHC)-linked diabetogenic genes (Idd-1) are unknown because of strong linkage disequilibrium within the MHC. By using a congenic NOD mouse strain that possesses a recombinant MHC from a diabetes-resistant sister strain, we have now shown that Idd-1 consists of at least two components, one in and one outside the class II A and E regions. A new susceptibility gene (Idd-16) was mapped to the < 11-centiMorgan segment of chromosome 17 adjacent to, but distinct from, previously known Idd-1 candidates, class II A, E, and Tap genes. The coding sequences and splicing donor and acceptor sequences of the Tnfa gene, a candidate gene for Idd-16, were identical in the NOD, CTS, and BALB/c alleles, ruling out amino acid changes in the TNF molecule as a determinant of insulin-dependent diabetes mellitus susceptibility. Our results not only map a new MHC-linked diabetogenic gene(s) but also suggest a new way to fine map disease susceptibility genes within a region where strong linkage disequilibrium exists.

Inhibition of experimental proliferative vitreoretinopathy by retroviral vector-mediated transfer of suicide gene. Can proliferative vitreoretinopathy be a target of gene therapy?

PURPOSE

To determine the potential of somatic gene transfer as a treatment for proliferative vitreoretinopathy (PVR), experimental PVR was induced in rabbits by intraocular injection of fibroblasts bearing the herpes simplex virus thymidine kinase (HStk) gene. These transduced cells should be susceptible to cytotoxicity by exposure to ganciclovir (GCV).

MATERIALS AND METHODS

Rabbit fibroblasts were transduced with retroviral vectors bearing an HStk gene. Proliferative vitreoretinopathy was induced by injection of 5 x 10(4) normal or HStk gene-transduced fibroblasts (HStk fibroblasts) into rabbit eyes. Ganciclovir (100 micrograms per eye) or saline was injected into the vitreous on days 0 and 4. Experimental animals were divided into three groups: group A received HStk fibroblasts with GCV; group B, normal fibroblasts with GCV; group C, HStk fibroblasts with saline. Proliferative vitreoretinopathy also was induced in several other groups of eyes, some receiving GCV and different proportions of HStk fibroblasts to normal fibroblasts, others receiving only normal fibroblasts and GCV. The eyes were examined by indirect ophthalmoscopy on days 4, 7, 14, and 28, and PVR was classified into six stages (0-5).

RESULTS

Proliferative vitreoretinopathy was induced and progressed over time in each group. On day 28, PVR was most severe in animals in group B (average stage, 4.6) and group C (average stage, 4.4). Proliferative vitreoretinopathy was inhibited in group A (average stage, 1.0). The groups that received mixed injection of HStk fibroblasts and normal fibroblasts had intermediate PVR. Results of histologic study showed no apparent toxic or pathologic reaction in the retinochoroidal tissue of group A animals.

CONCLUSIONS

Severity of experimental PVR clearly was reduced by transfer of the HStk gene and administration of GCV. This inhibitory effect also was produced by a combination of 10% HStk fibroblasts and 90% normal fibroblasts, indicating a significant bystander effect. These data suggest the potential of somatic gene therapy for the treatment of PVR.

Blood pressure control during surgical operations

In order to reduce intraoperative blood loss and spare blood transfusion, we developed a blood pressure control system using a state-predictive controller. Using adult mongrel dogs, the mean arterial pressure (MAP) was recorded from a femoral artery while trimethaphan camsilate was infused at constant rates. A pure delay plus a first-order delay model was then derived from the dose-response curves and the values of plant parameters (gain, time-constant, dead-time, and so on) were estimated based on the experimental data. For this model, a state-predictive servo system was designed to cope with the pure delay existing in the model, and simulated. In order to evaluate the accuracy and reliability of this system, we experimented on dogs. With a reference MAP set at 60 mmHg, the MAP reached the reference level in 5.8 to 26.5 min. The duration of error from the reference MAP (+/- 10%) was 2.3 +/- 3.9 min/h (n = 7). These results indicated the safety and stability of our system.

[Recurrence of pleomorphic xanthoastrocytoma six years after total removal of mural nodule: a case report]

A case of recurrent pleomorphic xanthoastrocytoma (PXA) was reported. A 46-year-old male underwent total removal of mural nodule from cystic tumor in the left temporal lobe in 1986. Histological diagnosis was astrocytoma. There were no abnormal neurological signs or symptoms after the operation. However, 6 years after the operation he complained of strong unpleasant smell as of rotten onions and was admitted to our hospital. MRI revealed a cystic tumor with a mural nodule which was enhanced markedly by Gd-DTPA in the same location as previous tumor site. He was operated upon again and tumor was removed with the cyst wall. Histological diagnosis was PXA. Surgical procedures for removal of cystic PXA has been controversial; removal of tumor only, tumor removal with biopsy of cyst wall, or tumor removal with resection of cyst wall. Real reason for recurrence of this tumor in our case is unknown. However, since astrocytoma cells were found in the biopsy specimen of the cyst wall at time of the first operation, the tumor might have recurred from these cells. Therefore, this time we removed not only the mural nodule but also the cyst wall, because the cyst wall peeled off easily. We would like to propose that PXA cyst walls should be resected, whenever possible, in order to accomplish total removal of tumor.

[The limitation of synchronization of pressure support ventilation (PSV) in ARDS]

PSV has been increasingly used as a partial ventilatory support for various types of respiratory failure. We experienced premature breath termination and double triggering in a patient with ARDS during PSV, and investigated the cause of this phenomenon using respiratory muscle pressure (Pmus). The analysis confirmed that the respiratory muscles and the ventilator did not coordinate synchronously in the patient with very low compliance of the respiratory system. The limitation of synchronization was attributable to fixed flow termination criteria in the present PSV algorithm. When dissynchronization is not manageable, other ventilatory modes (eg, APRV, PCV) allowing spontaneous ventilation should be considered as an alternative.

White matter changes caused by chronic solvent abuse

PURPOSE

To examine the brain damage of solvent abusers in Japan, where pure industrial toluene is frequently abused.

METHODS

Twenty solvent abusers 17 to 33 years of age with 7.2 +/- 4.0 years of abuse were examined with a 1.5-T MR imaging system.

RESULTS

White matter hyperintensities in cerebrum, brain stem, and cerebellum on T2-weighted images were found in seven cases. The extent of white matter change was most clearly shown on proton density-weighted images. The patients with restricted white matter change and intermediate white matter change showed white matter hyperintensities in the brain stem and cerebellum on T2-weighted images, in some cases, with additional hypointensities in the corresponding T1-weighted images. These patients had mainly abused pure toluene. The patients with diffuse white matter change showed obvious brain atrophy, including hippocampal atrophy and thinning of the corpus callosum. These patients had mainly abused lacquer thinner.

CONCLUSION

There are some patients with restricted but severe enough change to cause the neurologic symptoms in specific regions, such as the brain stem and/or cerebellum, before the brain atrophy becomes apparent. This suggests that the restricted white matter change represents not only an early change of diffuse white matter change, but at least in some cases also represents a qualitatively different change than that of diffuse white matter change. We suggest that pure toluene has a possible relation to this qualitative difference.

A new model of subretinal neovascularization in the rabbit

PURPOSE

To establish a new model of subretinal neovascularization (SRN) in the rabbit by implanting basic fibroblast growth factor (bFGF)-impregnated gelatin microspheres beneath the retina.

METHODS

Basic fibroblast growth factor-impregnated gelatin microspheres were prepared by forming a polyion complex between gelatin and bFGF. The microspheres, containing 2.5 micrograms of bFGF, were injected into the subretinal space of rabbit eyes (n = 29). Control eyes (n = 10) received bFGF-free gelatin microspheres. Eyes were followed up for 3 days to 8 weeks by ophthalmoscopy, photography, fluorescein angiography, light microscopy, and transmission electron microscopy.

RESULTS

Twenty of 24 experimental eyes (83%) showed fluorescein leakage from SRN 2 weeks after implantation of the bFGF-impregnated microspheres. This leakage continued for 2 to 6 more weeks. In striking contrast, control eyes showed no fluorescein leakage. Histologic examination revealed SRN in all the experimental eyes but in none of the control eyes.

CONCLUSIONS

Subretinal implantation of bFGF-impregnated gelatin microspheres induces reproducible SRN in the rabbit.

Increased catabolic rate of low density lipoproteins in humans with cholesteryl ester transfer protein deficiency

The cholesteryl ester transfer protein (CETP) transfers lipids among lipoprotein particles and plays a central role in lipoprotein metabolism. Humans with genetic deficiency of CETP have both elevated HDL cholesterol and apolipoprotein A-I concentrations as well as decreased LDL cholesterol and apolipoprotein B levels. The present study was undertaken to elucidate the metabolic basis for the decreased LDL cholesterol and apo B levels in CETP deficiency. We conducted a series of in vivo apo B kinetic studies in tow unrelated homozygotes with CETP deficiency and in control subjects. A primed constant infusion of stable isotopically labeled phenylalanine was administered to the two CETP deficient subjects and control subjects and apo B kinetic parameters in VLDL, intermediate density lipoproteins, and LDL were obtained by using a multicompartmental model. The fractional catabolic rates (FCR) of LDL apo B were significantly increased in the CETP-deficient subjects (0.56 and 0.75/d) compared with the controls (mean FCR of 0.39/d). Furthermore, the production rates of apo B in VLDL and intermediate density lipoprotein were decreased by 55% and 81%, respectively, in CETP deficiency compared with the controls. In conclusion, CETP-deficient subjects were demonstrated to have substantially increased catabolic rates of LDL apo B as the primary metabolic basis for the low plasma levels of LDL apo B. This result indicates that the LDL receptor pathway may be up-regulated in CETP deficiency.

Increased muscle sympathetic nerve activity after glucagon administration in man

Muscle sympathetic nerve activity (MSNA) after glucagon administration was quantitatively measured in five healthy male volunteers (age: 20-28 years old). After an overnight fasting, 1 mg glucagon dissolved in a 1-ml vehicle was injected i.v. as a bolus. MSNA, ECG and blood pressure were simultaneously recorded 15 min before and after the injection. MSNA (bursts/min), heart rate (HR), and systolic and diastolic blood pressures (dBP and sBP) were significantly increased at 2-3 min after glucagon injection. Their means and standard deviations of control for 15 min vs. 3 min after the injection were in the five subjects; MSNA, 10 +/- 6 vs. 30 +/- 10 bursts/min, HR, 61 +/- 10 vs. 76 +/- 8 beats/min, dBP, 66 +/- 9 vs. 91 +/- 9 mmHg and sBP, 122 +/- 12 vs. 152 +/- 11 mmHg. These results suggest that glucagon has a direct facilitatory effect on the central sympathetic nervous system.

In vitro studies of human choroidal endothelial cells

Vascular endothelial cells play an important role in progression or healing of various retinal or choroidal diseases and they have a broad organ specificity. We have grown and studied human choroidal endothelial cells (CECs) cultured in a collagen gel, where they form tube-like structures. CECs were differentially isolated from choroidal tissues and cultured to near homogeneity. The cells were embedded in a type I collagen gel in 24-well culture dishes and incubated with M199 medium containing 10% fetal calf serum. Gels were observed using phase contrast microscopy and were evaluated histologically by light and electron microscopy. The CECs were strongly positive for factor VIII-related antigen and actively ingested diI-acetylated LDL, indicating their endothelial nature. Ultrastructural analysis of the tube-like structures revealed a central lumen surrounded by cells joined apically by junctions and showing prominent pinocytotic activity, fenestrations and basement membrane formation; these features are typical of CECs in vivo. This preparation should be a useful tool to study the development of physiology and pathology of choroidal endothelium.

Effects of sodium metabisulphite on guinea pig contractile airway smooth muscle responses in vitro

BACKGROUND

Sodium metabisulphite (MBS) is known to induce bronchoconstriction in asthmatic patients. The effects of MBS on guinea pig airway smooth muscle and on neurally mediated contraction in vitro have been examined.

METHODS

Tracheal and bronchial airway segments were placed in oxygenated buffer solution and electrical field stimulation was performed in the presence of indomethacin (10(-5) M) and propranolol (10(-6) M) for the measurement of isometric tension. Atropine (10(-6) M) was added to bronchial tissues.

RESULTS

Concentrations of MBS up to 10(-3) M had no direct effect on airway smooth muscle contraction and did not alter either tracheal smooth muscle contraction induced by electrical field stimulation at all frequencies or acetylcholine-induced tracheal smooth muscle contraction. There was a similar response in the absence of epithelium, except for potentiation of the response induced by electrical field stimulation at 0.5 Hz (24 (10)% increase). However, MBS (10(-5), 10(-6) and 10(-7) M) augmented neurally-mediated non-adrenergic non-cholinergic contractile responses in the bronchi (13.3 (3.2)%, 23.8 (9.6)%, and 6.4 (1.6)%, respectively). MBS had no effect on the contractile response induced by substance P, but at higher concentrations (10(-3) M and 10(-4) M) it caused a time-dependent attenuation of responses induced by either electrical field stimulation or exogenously applied acetylcholine or substance P.

CONCLUSIONS

MBS had no direct contractile responses but enhanced bronchoconstriction induced by activation of non-cholinergic neural pathways in the bronchus, probably through increased release of neuropeptides. At high concentrations MBS inhibited contractile responses initiated by receptor or neural stimulation.

Effects of timing on ventriculoarterial coupling and mechanical efficiency during intraaortic balloon pumping

To evaluate the effects of deflation timing of an intraaortic balloon (IAB) on ventriculoarterial (VA) coupling and left ventricular (LV) mechanics, we assessed contractility: Emax (mmHg/ml); VA coupling: Ea/Ees; myocardial oxygen consumption: LV pressure-volume area (PVA); and energy efficiency: external work (EW)/PVA during IAB pumping, using four different timing intervals of IAB deflation in eight dogs weighing 19.8 +/- 3.8 kg. In the conventional timing group (G-conv), the IAB was deflated before LV systole. In the real time group (G-1, 2, 3), the IAB was deflated during isovolumic contraction (ICP), and the group was subdivided into three groups based on time of deflation: G-1 at the onset of ICP, G-2 at the midpoint of ICP, and G-3 at the end of ICP. Percent changes in values with IAB compared to those without assist were calculated. Based on the results, IAB deflation during ICP reduces LV end-systolic pressure and significantly optimizes VA coupling and LV efficiency during IAB support, compared with conventional timing.

[Two cases underwent patch closure and mitral annuloplasty for ventricular septal perforation and mitral regurgitation caused by acute inferior myocardial infarction]

Two cases underwent successful operation for the ventricular septal perforation (VSP) and mitral regurgitation (MR) caused by acute myocardial infarction (AMI) are reported. Patch closure of VSP and mitral annuloplasty (MAP) by Kay-Suzuki method were performed. Location of VSP were posterior ventricular septum and moderate MR were detected in both cases. Case 1 was a 74-year-old man. Four weeks after AMI, patch closure of VSP through right ventricular approach and MAP through trans-atrial approach and also aorto-coronary bypass to left anterior descending artery were performed. Doppler echocardiography was effective to evaluate the severity of VSP and MR. Case 2 was a 69-year-old man. Eight days after AMI, patch closure of VSP and MAP were performed through biventricular approach. Postoperative examination revealed the disappearance of left-to-right shunt and MR in both cases. These cases operated successfully were thought to be rare.

Analysis of structure of sugar-beet pectin by enzymatic methods

The structure of alkali-soluble pectin (ASP) prepared from sugar-beet pulp was determined. ASP was sequentially degraded by pure galactanase, rhamnogalacturonase and arabinosidase and sugar compositions and NMR analysis of the products used to assign the following tentative structure to ASP: a backbone based on units of -->4)-alpha-D-GalpA-(1--> 2)-alpha-L-Rhap-(1-->, and side chains both of arabinan and of arabinogalactan.

[Vasoreactivity of normal brain tissue in cases of arteriovenous malformations--evaluation by 123I-IMP SPECT using acetazolamide]

Arteriovenous malformations (AVMs) are usually associated with diminished cerebral blood flow (CBF) in the parenchyma surrounding AVMs because of the steal phenomenon. Vasoreactivity in the parenchyma surrounding AVMs may change because of ischemia and abnormal hemodynamics. The aim of this study was to investigate vasoreactivity in parenchyma surrounding AVMs. Quantitative single-photon emission computed tomography using N-isopropyl-p-I-123 iodoamphetamine (IMP-SPECT) was performed before and after intravenous administration of acetazolamide (Diamox). Diamox is a potent cerebral vasodilator which causes tissue acidosis, and IMP-SPECT was performed 10 min after intravenous infusion of a 1g dose. The subjects were 8 patients with AVMs. The AVM was in the frontal lobe in 3 patients, the temporal lobe in 1 patient, the lateral ventricle in 1 patient, the midbrain in 1 patient, the basal ganglionic region in 1 patient, and the vein of Galen in 1 patient. A rotating gamma camera with two heads was used to perform SPECT. IMP was injected into an arm vein, and a 5-min period of blood withdrawal, 1 ml/min, was started simultaneously from a small catheter placed in the radial artery. Kuhl's method was used to quantify cerebral blood flow (CBF). Multiple contiguous 6-pixel-diameter region of interest (ROI) circles along the cerebral cortex and cerebellar hemisphere were used, and ROIs which included the AVM nidus, draining veins or infarctions were excluded from the study. Vascular territories containing arteries feeding the AVM were defined as near-ROIs on SPECT, and all other ROIs were defined as far-ROIs. (ABSTRACT TRUNCATED AT 250 WORDS)

Do recently developed techniques for skull base surgery increase the risk of difficult airway management? Assessment of pseudoankylosis of the mandible following surgical manipulation of the temporalis muscle

We report our experience with anesthetic care for six patients with pseudoankylosis of the mandible following neurosurgical procedures, four of whom required fiberoptically guided intubation for anesthesia. We suggest that the development of operative approaches and reconstruction techniques in skull base surgery may increase the risk of difficult airway due to limitation of mouth opening.