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著者人数: 13名, Accepted: 2018-07-23, 資料番号: SA1180184000

A comparison is made of irradiation damage in standard trench and fine pattern trench IGBTs (Insulated-Gate Bipolar Transistors) by 2-MeV electron irradiation at room-temperature. The electron fluence ranged from 10 14 to 10 15 e/cm 2 . Two different types of IGBTs are studied,with differences in trench depth, in trench width gate oxide thickness. For both types of devices the breakdown voltage is the same and 400 V. It is shown that in the range studied, the electron fluence dependency of the radiation-induced defects using deep-level transient spectroscopy (DLTS) and the voltage shift due to the radiation-induced interface traps (ΔVit) and the voltage shift due to the radiation-induced oxide traps (ΔVot) are different. From the difference in post-rad C-V characteristics it is derived that in one type of devices the B dopants become deactivated by H released by the high-energy electrons from the Phosphorus-Silicate-Glass (PSG) passivation layer.

The relationship between the minority carrier lifetime and bulk defects and between this lifetime and the interface states due to 2 MeV electron irradiation were investigated using deep-level transient spectroscopy (DLTS) and the charge separation technique, respectively. There seems to be a correlation between the change in lifetime and the interface traps generated due to electron irradiation. For the same level of interface trap density after a fluence of 1×1014 e/cm2 electron irradiation due to Fowler–Nordheim (FN) high electric field stress, the lifetime did not changed. Due to the creation of a deeper state, which is probably a defect including V2 and H with increasing electron fluence, the lifetime decreases further. It is thought that the Si–H bonds at the Si–SiO2 interface are broken and dissociated hydrogen is introduced in the silicon bulk during the electron irradiation.

Plasma-based ion implantation (PBII) as a tool for polymer modification is studied. Polymeric films have good performances for flexible use, such as food packaging or electronic devices. Compared with inorganic rigid materials, polymers generally have large permeability for gases and moisture, which causes packaged contents and devices to degrade. In order to add a barrier function, surface of polymeric films are modified by PBII. One of the advantageous features of this method over deposition is that the modified surface does not have peeling problem. Besides, micro-cracks due to mechanical stress in the modified layer can be decreased. From the standpoint of mass production, conventional ion implantation that needs low-pressure environment of less than 10−3 Pa is not suitable for continuous large-area processing, while PBII works at rather higher pressure of several Pa. In terms of issues mentioned above, PBII is one of the most expected techniques for modification on flexible substrates. However, the mechanism how the barrier function appears by ion implantation is not well explained so far. In this study, various kinds of polymeric films, including polyethyleneterephthalate (PET), are modified by PBII and their barrier characteristics that depend on the ion dose are evaluated. In order to investigate correlations of the barrier function with implanted ions, modified surface is analyzed with X-ray photoelectron spectroscopy (XPS). It is assumed that the diffusion and sorption coefficients are changed by ion implantation, resulting in higher barrier function.

The degradation of the electrical properties of IGBTs (Insulated-Gate Bipolar Transistors) by 2-MeV electron irradiation at high-temperatures was studied. The irradiation temperatures were 25, 100, 200 and 300∘C, and the fluence was fixed at 1015 e/cm2. For most experimental conditions, the threshold voltage (VTH) is observed to recover partially during 100∘C and the saturation voltage (VCEsat) increase is most pronounced at 100∘C. It is shown that in this irradiation temperature range, the temperature dependency of the voltage shift due to the radiation-induced interface traps (Δ Vit) and the voltage shift due to the radiation-induced oxide traps (Δ Vot) are different, which suggests a possible degradation mechanism for these phenomena. It is tentatively suggested that the diffusion of hydrogen released from the gate by the 2-MeV electrons passivates the interface traps during the high temperature irradiation.

The impact of radiation damage on the device performance of 4H-SiC Schottky diodes, which are irradiated at room temperature with 2-MeV electrons is studied. After irradiation the reverse current increases, while the forward current and the capacitance decrease with barrier height and carrier density. The decrease of the barrier height is mainly responsible for the increase of the reverse current, while the decrease of the forward current for a high fluence is caused by the increase of the resistance in the bulk of the crystal. Although no electron capture levels are observed before irradiation, three electron capture levels (E1, E2, and E3) are induced after irradiation. It is noted that the decrease in carrier density is partly caused by the contribution of non-observed electron capture level in the DLT spectrum, which compensates the free carriers.

One hundred and seventy patients with ruptured cerebral aneurysms were treated by coil embolization from September 1997 to December 2002. After January 2000, coil embolization was selected as the first-choice treatment for ruptured aneurysms. During this period, the authors investigated the number of aborted cases, the number of complications, and how many patients could be treated by coil embolization according to the locations of ruptured cerebral aneurysms. One hundred and ninety-five sessions were performed on 170 patients, and 13 sessions (6.7%) were aborted mainly because of the difficulty of the approach and the wide necks of the aneurysms. In four patients, although procedural perforation and haemorrhage occurred, the outcome was good or excellent. Eight poor-grade patients experienced haemorrhage after coil embolization and seven patients died. The volume embolization ratios of small and large aneurysms were 27% and 21%, and the recanalization of small and large aneurysms occurred in 9% and 38% of patients, respectively. From January 2000 to December 2002, 119 (66%) of 180 ruptured cerebral aneurysms were treated by coil embolization. According to the location of aneurysms, 89% vertebrobasilar, 87% anterior cerebral, 65% internal carotid and 24% middle cerebral artery aneurysms could be treated by coil embolization. Because the tight packing of large aneurysms was difficult, the recanalization rate of large aneurysms was high. However, the results of small aneurysms were satisfactory. Almost 90% of vertebrobasilar and anterior cerebral artery aneurysms could be treated by coil embolization.

The response of the turn-off time, forward voltage drop and leakage current of IGBT (insulated-gate bipolar transistor) irradiated at different temperatures by 2-MeV electrons for fluences between 1013 and 1015 e/cm2, is described. The carrier lifetime, derived from the exponential part of the turn-off current signal, drops from 719 ns before irradiation to 704, 465 and 265 ns, after exposure to a 1013, 1014 and 1015 e/cm2 fluence, respectively. The forward voltage drop increases from 3.31 V before irradiation to more than 11.0 V for 1015 e/cm2. From the injection current dependence of the lifetime it is shown that the dominant process at high injection changes from Auger recombination before irradiation to Shockley–Read–Hall (SRH) recombination after irradiation. It is finally shown that the degradation of the IGBT electrical parameters decreases with increasing irradiation temperature.

The degradation of polycrystalline silicon (Poly-Si) films, subjected to 20-MeV alpha-ray irradiation, is studied. To investigate the radiation source dependence, 20-MeV proton and 1-MeV electron irradiation have been performed as well. The damage of alpha-rays is one and three orders of magnitude larger than for protons and electrons. The radiation source dependence of the performance degradation is attributed to the difference of mass and the probability of nuclear collisions for the formation of lattice defects. It is concluded that the combination of the induced lattice defects in the grain itself and the interface state density at its boundary are mainly responsible for the degradation of the Poly-Si films by high-energy particle irradiation. The degradation of the Poly-Si films can also be explained by a finite grain-bulk dynamic resistance r/sub c/ and a large-barrier dynamic resistance r/sub SCR/ based on the Schottky barrier diode degradation mechanism.

The radiation damage of 20 MeV proton irradiated n-MOSFETs fabricated in a BiCMOS process is studied. From the input characteristics of the drain current, the activation energy of the voltage shift based on trapped-oxide charge (ΔVNot) and SiO2/Si interface traps (ΔVNit) for a total ionizing dose of 35 Mrad(Si) is calculated to be 0.40 and 0.26 eV, respectively. Also, the activation energy for the annealing of the density of radiation-induced interface traps (Nit) estimated from the base current of the bipolar mode operation corresponds to 0.27 eV. From the activation energy of the ohmic drain–source current recovery of 0.40 eV it can be concluded that the trapped-oxide charge is mainly responsible for the degradation of the transistor performance.

Results are presented of a study on the mechanical stress dependence of the resistance of polycrystalline silicon (Poly-Si) films doped with different atomic species, namely, with boron and phosphorus ions. B-doped films of 400 nm and P-doped films of 250 nm thickness were deposited by low-pressure chemical vapor deposition at 620 °C on thermally oxidized silicon wafers. A controlled amount of external stress was applied to the silicon wafers in order to investigate the impact on the electrical performance of the implanted Poly-Si resistors. The resistance of the B-doped Poly-Si films is shown to increase by the mechanical stress, while the resistance of the P-implanted Poly-Si films remained unchanged. It is concluded that this difference is related to the structural differences between Poly-Si films implanted with boron and phosphorus, respectively.

Results are presented of a study on the effects of total ionization dose and displacement damage, induced by high-energy electrons, protons and alphas, on the performance degradation of flash memory cells integrated in a microcomputer. A conventional stacked-gate n-channel flash memory cell using a 0.8 μm n-polysilicon gate technology is employed. Irradiations by 1-MeV electrons and 20-MeV protons and alpha particles were done at room temperature. The impact of the fluence on the input characteristics, threshold voltage shift and drain and gate leakage was investigated. The threshold voltage change for proton and alpha irradiations is about three orders of magnitude larger than that for electrons. The performance degradation is mainly caused by the total ionization dose (TID) damage in the tunnel oxide and in the interpoly dielectric layer and by the creation of interface traps at the Si–SiO2 interface. The impact of the irradiation temperature on the device degradation was studied for electrons and gammas, pointing out that irradiation at room temperature is mostly the worst case. Finally, attention is given to the impact of isochronal and isothermal annealing on the recovery of the degradation introduced after room temperature proton and electron irradiation.

Results are presented of a study on the radiation damage in n-MOSFETs fabricated in a 0.8 μm single-well BiCMOS process, subjected to 20-MeV protons. A comparison is made with the degradation behavior induced by γ-ray irradiation. Finally, the recovery under post-irradiation thermal annealing is also reported.

The device performance degradation and the induced lattice defects of shallow trench isolation (STI) n þ p diodes, subjected to different high energy particle irradiations will be described. The diodes were irradiated with 1-MeV neutrons, 2-MeV electrons and 20-MeV protons. Insight into the displacement damage mechanisms is obtained by analyzing the relation between the current damage coefficient, and the calculated non-ionizing energy loss. Deep level transient spectroscopy is used to detect the radiation-induced electron capture levels. Some levels are thought to be related to the degradation of the STI interfaces. The degradation of the electrical performance results from the induced defects. A different degradation behavior in dependence of the irradiation particle is found for meander diodes compared with square diodes. 2002 Elsevier Science B.V. All rights reserved.

The radiation damage of polycrystalline silicon (poly-Si) films, subjected to 20-MeV alpha ray, 20-MeV proton and 1-MeV electron irradiation, is studied. The degradation of the poly-Si films by irradiation is caused by the induced lattice defects in the grain itself rather than at its boundaries.

Results are presented of a study on the radiation damage and its recovery behavior resulting from thermal annealing of n-MOSFETs fabricated in a 0.8-μm single-well BiCMOS process, subjected to γ-rays, 1-MeV electrons and 1-MeV neutrons. After irradiation, the base (substrate) current and interface trap density normally increase with increasing fluence. This result points out that both ionization damage in the gate oxide and lattice defects in the p-well are induced by the irradiation. The interface trap density recovers by 85% for γ-ray irradiation with a fluence of 1×108 rad, after a 300 °C annealing.

The irradiation damage in Si-planar-doped AlGaAs pseudomorphic HEMT's integrated in 50 GHz monolithic microwave integrated circuits (MMIC's) and subjected to 20-MeV /spl alpha/ and /spl gamma/-ray irradiation is studied. Both the static and the high frequency device parameters have been analyzed. It is shown that the drain current and the effective mobility decrease after irradiation, while the threshold voltage shifts in a positive direction. The degradation of the device performance increases for higher fluence. The decrease of the mobility is thought to result from the scattering of channel electrons by the induced lattice defects and also from the decrease of the electron density in the two dimensional electron gas (2DEG) region. Moreover, the noise figure increases with increasing fluence, while the gain decreases. After 150/spl deg/C post-irradiation thermal annealing for 15 min, the noise figure and gain for 1/spl times/10/sup 12/ /spl alpha//cm/sup 2/ recovers by 67 and 19%, respectively.

In the last 30 years, maternal and perinatal mortality rates have markedly improved in Japan. These results are supported by the advanced technologies and newly developed treatments in obstetric and neonatal medicine, the evidence of which will be described through the authors' experiences. Ultrasound-guided treatments for fetuses and pediatric surgery for extremely tiny infants have been performed with cooperation among cardiac surgeons, anesthesiologists and perinatologists. The remarkable achievements in neonatal medicine are surfactant replacement therapy, application of high frequency oscillation (HFO) respirator, nitric oxide and extracorporeal membrane oxygenation (ECMO) systems and transcutaneous blood gas monitoring. The possibility to have a safe pregnancy and delivery arose for women with severe medical complications such as diabetes mellitus (DM), heart diseases, and hemo-dialysis, factors formerly regarded as contraindications to pregnancy. The accumulative data of these high-risk pregnancies treated in our center are introduced. It is noted that molecular mechanisms in fetal growth have been elucidated to some extent. The insulin-like growth factor I (IGF-I) and IGF-binding protein 1 (IGFBP1) system, and cytokines, are involved in the fetal growth. Newly developed treatments such as urinary trypsin inhibitor (Urinastatin) for prevention of preterm delivery and amnioinfusion to cases of preterm premature rupture of the membrane are summarized. Finally, the reference to advanced medicine and its side effects lead to broad discussions regarding the future development of perinatal medicine.

The separation of carbon dioxide through the facilitated transport membrane has been investigated. The membrane remains to be effective for more than a month under reduced pressure by using a gel membrane as a support for the liquid membrane. Moreover, carbon dioxide permeation rate and selectivity increase by adding crown ether analogous to potassium carbonate aqueous solution.

RITE is carrying out a research project to develop novel membranes for carbon dioxide separation. We study Cardo polyimides and plasma treated membranes. Cardo polyimides show good CO2/N2 separation properties. Cardo polyimides have high CO2 permeabilities and large CO2 solubilities compared to conventional polymers. Membranes polymerized from monomers by plasma irradiation containing ethylene oxide structures was observed high CO2/N2 selectivity. Composite membrane which formed from a thin layer of plasma polymerized membrane on a support improved CO2/N2 selectivity compared with the support.

OBJECTIVE: This study aimed to develop a model for predicting the outcome and evaluating the treatment of patients with threatened of preterm labour. METHODS: Clinical data from 236 patients at < 32 weeks gestation who were in preterm labour were analysed to develop a discriminant function using multiple logistic regression to identify significant risk factors. The function was validated retrospectively in a further 501 patients and prospectively in 63 patients with premature labour. RESULTS: Factors that increased the risk of preterm birth were premature rupture of the membranes, intrauterine infection, dilatation of the cervix and uterine bleeding. Factors that decreased the risk of preterm birth were hospital admission after 28 weeks of gestation and intravenous administration of ritodrine. The predictive accuracy of the function was 75.4% in the 236 patients analysed, 84.8% in the further 501 retrospectively studied patients and 85.7% in the prospective group. CONCLUSIONS: The discriminant function described was clinically useful for predicting the outcome of threatened preterm labour before initiating treatment and for determining the medical care of patients, including maternal transfer to a high-level perinatal care centre.

Irradiation damage and its recovery behavior resulting from thermal annealing in AlGaAs/GaAs pseudomorphic HEMTs, subjected to 1-MeV electrons, 1-MeV fast neutrons and 220-MeV carbon, are studied. The drain current and effective mobility decrease after irradiation, while the threshold voltage increases in positive direction. The decrease of the mobility is thought to be due to the scattering of channel electrons with the induced lattice defects and also to the decrease of the electron density in the two-dimensional electron gas (2DEG) region.

A new highly stable magneto-impedance (MI) micro magnetic sensor with a pair of zero-magnetostrictive amorphous wires is presented. The sensor picks up a first pulse in an induced oscillatory pulse voltage at a wire coil using an analog switch. High temperature stability in the MI sensor is established in which zero drift for temperature variation from 20/spl deg/C to 80/spl deg/C is 0.6%/FS (0.01.%/FS/spl deg/C). The highly stable MI sensor will be useful for application to automobile controls.

The degradation of npn Si transistors, subjected to /spl gamma/ and 1-and 2-MeV electrons at different irradiation temperature, is studied. For the 20/spl deg/C irradiation I/sub B/ increases significantly, while I/sub C/ markedly decreases for V/sub BE/ above 0.6 V. The radiation-induced degradation becomes significantly smaller for higher exposure temperatures. For the 200/spl deg/C irradiation, I/sub B/ remains of the same order as before irradiation, while I/sub C/ is nearly identical. It is also noticed that h/sub FE/ for the 200/spl deg/C /spl gamma/-ray irradiation amounts to 82% of the starting value. A broad distribution of hole trapping levels is observed in the base region for the 20/spl deg/C exposure, while an electron trap with energy level Ec - 0.18 eV and a broad DLTS signal around 150 K was found in the collector region. The hole capture levels in the base are related to radiation damage at the Si-SiO/sub 2/ interface region. It is concluded that the radiation-induced defects in the base and collector regions correlate well with the device degradation of the npn Si transistors.

This paper proposes a new algorithm on image compression. The algorithm is obtained by combining and enhancing two previously announced research results, i.e. on the best wavelet packets bases determination in rate-distortion sense, and on image coding using zero trees of wavelet coefficients. The method in this paper begins with searching for the best bases wavelet packet decomposition of signal according to the preassigned rate and distortion values. Based on this information, we perform zero trees algorithm on the selected bases. We present several simulation results on image compression to show the effectiveness of the proposed method.

This paper describes a 10 Gb/s throughput FEC (forward error correction) codec for long-haul optical transmission systems. The FEC codec uses concatenated BCH(2040, 1930) and BCH(3860, 3824), which provides an excellent 7.98 dB net coding gain at 1E/sup -12/ corrected bit error rate with 6.69% redundancy by applying three times iterative decoding. Furthermore, by applying a time-multiplexed decoder and skipping Chien search process for uncorrectable BCH(3860, 3824) codewords, the FEC codec achieves a low power consumption of 3.15 W and a low gate count of 2.40 Mgates using 0.15 /spl mu/m CMOS technology.

The degradation of AlGaAs/GaAs pseudomorphic HEMTs by 220-MeV carbon, 1-MeV electron and neutron irradiation and their recovery by subsequent isochronal annealing are investigated and compared with results obtained on irradiated InGaP/InGaAs p-HEMTs.

In Japan, power systems have become complicated due to load increases. Problems with power system stability and short circuit current have occurred in large power systems and must be resolved. This requires not only the installation of new equipment but also the effective utilization of existing equipment, while also considering economic costs. The de-regulation and requirements for cost reduction increase the demands of power accommodation between large areas and between small areas. Power electronics technology is a possible solution. In this paper, the authors describe how an installation of a large back-to-back (BTB) system guarantees the beneficial effects of reducing short circuit current, improving power system stability and controlling power flow easily in the bulk power system.

Objective: Short-latency somatosensory evoked potential (SSEP) monitoring has been reported to be useful in predicting neurological outcome in patients with cardiac arrest and hypoxic-ischemic encephalopathy. To obtain the immediate data of SSEP and evaluate the relationship between the presence of cortical activity and the recovery of consciousness, SSEP was recorded immediately after return of spontaneous circulation. Design and setting: Prospective observational study in an intensive care unit of a university general hospital. Patients: The study included 30 patients resuscitated from out-of-hospital cardiac arrest. Interventions: Basic and advanced cardiac life support, and intensive care. Measurements and results: SSEP were recorded between 40 and 170 min (median 65) after spontaneous circulation returned. In the initial study all 30 patients showed the Erb's point potential and the N11-13 component, while only 12 (40%) showed cortical activity. Patients were assessed neurologically for recovery of consciousness until 1 month after cardiac arrest. Of 12 these patients 8 recovered consciousness within 10 days, while all patients without cortical activity died without opening their eyes. Conclusion: Even immediately following resuscitation, absence of cortical activity in SSEP indicates unlikelihood of recovering consciousness, while the preservation of such activity suggests that consciousness is improved. The result promises further accumulation of patients to validate the predictive ability of SSEP in managing postresuscitated patients.

A double-blind, randomized, placebo-controlled trial was conducted to evaluate whether treatment with Antithrombin (AT) concentrates improved the clinical and perinatal outcome in patients with severe preeclampsia. Severe preeclamptic patients (24 to 35 weeks of gestation. Gestosis Index (GI)or = 6 points) were randomized into two groups: 66 received AT and 67 received placebo. There were no statistical differences in the clinical profiles of the two groups. Study drugs were given intravenously once daily for 7 consecutive days. Maternal symptoms were evaluated from the difference of GI between before and after treatment, and fetal findings were evaluated from the changes of the biophysical profile score and the estimated fetal weight gain. Improvement was significantly greater in the AT group for both the GI (p = 0.020) and the estimated fetal weight gain (p = 0.029). The improvement of coagulation parameters was also evaluated. The D-dimer levels increased significantly in the placebo group (p = 0.026), but did not change in the AT group. Gestation was significantly prolonged (p = 0.007), and the number of low-birth weight infants was significantly smaller (p = 0.011) in the AT group. No adverse events related to AT were observed. It is revealed that AT concentrate therapy for preeclampsia is effective and safe, leading to an improved perinatal outcome.

Pranlukast (8-[p-(4-phenylbutyloxy) benzol] amino-2-[tetrazol-5-yl]-4-oxo-4H-1-benzopyran hemihydrate), a selective cysteinyl leukotriene receptor antagonist, has been reported to exhibit not only antileukotrine activity but also pharmacological activity including antieosinophilic effects.This study was designed to investigate whether the antiasthmatic activity of pranlukast is associated with a reduction in eosinophilic inflammation.A double-blind, randomized, crossover design was used. Subjects received 225 mg of pranlukast or placebo orally twice daily for 4 weeks and then, after a washout period of at least 4 weeks, crossed over to receive the alternative treatment. We assessed the effects of pretreatment with pranlukast on bronchoconstriction precipitated by inhalation of methacholine in 32 adult patients with mild or moderate bronchial asthma; those who were in stable clinical condition were allocated to this study. Blood and sputum samples were taken the morning of the methacholine provocation test. Eosinophil counts and measurement of eosinophilic cationic protein (ECP) were performed.After the 4 weeks of treatment with pranlukast, patients' symptoms, blood eosinophils, serum ECP, sputum eosinophils, and sputum ECP were significantly decreased. Furthermore, values of PC20-methacholine significantly improved in the treatment with pranlukast.Our results suggest that pranlukast has an anti-inflammatory effect on bronchial eosinophilic infiltration. This study raises further interesting therapeutic possibilities and argues for further trials of new approaches to the treatment of bronchial asthma.

Publisher Summary This chapter describes the experiments undertaken to study the effect of an oil phase on the sensory intensity of the salt taste of NaCl in an oil/water emulsion using the magnitude estimation technique. The perceived intensity of the salt taste in emulsions is much higher than that of the solution without oil droplets at the same NaCl concentration. The salt taste of low-fat emulsion (35 wt % oil) is less intense than that of the high-fat emulsion (70 wt % oil), suggesting that the sensory score depends on the oil content. The NaCl concentration measured in the water phase of the high-fat emulsion, containing 0.9 wt % NaCl, is 2.66 wt %. The sensory score of the high-fat emulsion, containing 0.9 wt % NaCl, is much lower than that of a 2.66 wt % NaCl solution without oil droplets. These results suggest that the oil phase enhancement of the perceived intensity of the salt taste in an oil/water emulsion might be because of the increased concentration of NaCl in the water phase and the suppressed contact of NaCl to gustatory cells.

Results are presented of a study on the mechanical stress dependence of the resistance of polycrystalline silicon (Poly-Si) films, doped with different atomic species. Two types of Poly-Si film implanted with boron and phosphorus ions were studied, namely, B-doped films of 400 nm and P-doped layers of 250 nm thickness, which were deposited by LPCVD at 620 °C on thermally oxidized silicon wafers. Film doping was done by ion implantation at 50 keV, with a dose of boron and phosphorus of 2 × 1014 and 5.3 × 1014 cm−2, respectively. The Poly-Si films were annealed in a H2 ambient at 1000 °C for 20 min to activate the implanted atoms. A controlled amount of external stress was applied to the silicon wafers in order to study the impact on the electrical performance of the implanted Poly-Si resistors. The resistance of the B-doped Poly-Si films is shown to increase by the mechanical stress, while the resistance of the P-implanted Poly-Si films remained unchanged. It is concluded that this difference is related to the structural differences between Poly-Si films implanted with boron and phosphorus, respectively.

Albeit its exact pathogenesis is still ambiguous; aspirin-intolerant asthma is one of several types of asthma for which antileukotriene therapy is useful, because it is widely accepted that bronchial over-production of leukotrienes may be involved in its pathogenesis. Pranlukast (8-[p-(4-phenylbutyloxy) benzol] amino-2-(tetrazol-5-yl)-4-oxo-4H-1-benzopyran hemihydrate), a selective cysteinyl leukotriene receptor antagonist, is now widely used in the treatment of asthma.This study was designed to investigate the protective effect of pranlukast on airway sensitivity to sulpyrine provocation testing, bronchial responsiveness to methacholine provocation testing, and to investigate whether this protective activity is associated with a reduction in aspirin-induced excretion of urinary LTE4 (uLTE4), a marker of the cysteinyl leukotriene (LT) overproduction that participates in the pathogenesis of aspirin-induced asthma.We assessed the effects of pretreatment with pranlukast on bronchoconstriction precipitated by inhalation of methacholine and sulpyrine in 16 adult patients with mild or moderate aspirin-intolerant asthma; those who were in stable clinical condition and were hypersensitive to sulpyrine provocation testing were allocated to this study. A double-blind, randomized, crossover design was used. uLTE4 was measured using combined reverse-phase high-performance liquid chromatography (rp-HPLC)/enzyme immunoassay.Pranlukast protected against analgesic-induced bronchoconstriction through mechanisms that were not related to the bronchodilator property, but were related to the improvement both of bronchial hyperresponsiveness and hypersensitivity to analgesic (P0.005 and P0.0001). Pranlukast showed little effect on excretion of uLTE4.These results support the hypothesis that cysteinyl leukotriene is one of the most important components in the pathogenesis of aspirin-intolerant asthma. Pranlukast improves not only hypersensitivity to analgesic, but also bronchial hyperresponsiveness in aspirin-intolerant asthma. It is also possible that pranlukast has another anti-asthmatic effect besides that of a leukotriene receptor antagonist.

This study was designed to investigate the protective effect of cromolyn sodium on airway sensitivity to sulpyrine, and bronchial responsiveness to methacholine, and to investigate whether this protective activity is associated with reduction in aspirin-induced excretion of urinary leukotriene E4 (u-LTE4), a marker of the cysteinyl LT overproduction that participates in the pathogenesis of aspirin-induced asthma. We assessed the effects of pretreatment with cromolyn sodium on bronchoconstriction precipitated by inhalation of methacholine and sulpyrine in 16 adult patients with mild or moderate aspirin-intolerant asthma; those who were in stable clinical condition and were hypersensitive to a sulpyrine provocation test were included in this study. A double-blind, randomized, crossover design was used. u-LTE4 was measured using combined reverse-phase high-performance liquid chromatography enzyme immunoassay. Cromolyn sodium protected against analgesic-induced bronchoconstriction through mechanisms that are not related to its bronchodilator property, but to the improvement of both bronchial hyperresponsiveness and hypersensitivity to analgesics (p0.01 and p0.001). Although excretion of u-LTE4 did not increase after the methacholine provocation test, it significantly increased after sulpyrine provocation (p0.01). Furthermore, after pretreatment with cromolyn sodium, the maximum level of u-LTE4 after the sulpyrine provocation test was significantly lower than in controls (p0.01). These results support the hypothesis that cysteinyl LT is one of the most important components in the pathogenesis of aspirin-intolerant asthma. Cromolyn sodium improves both hypersensitivity to analgesics, and bronchial hyperresponsiveness in aspirin-intolerant asthma.

A case of intraaxial clear cell ependymoma is reported. A 46-year-old man complained of right hemiparesis. CT scan showed a mass lesion on the median plane with a huge cyst in the left frontal lobe. MRI showed an iso-low intensity mass by T1-weighted image. The tumor was heterogeneously enhanced by Gd-DTPA and the wall was enhanced as well. Angiogram revealed a tumor stain from the right internal carotid artery. The main mass of the tumor was totally removed but the cystic wall was left removed. Histopathological examination revealed clear cell ependymoma. Immunohistochemical examination revealed that, although vimentin and NSE were positive, GFAP, synaptophysin and S-100 were negative. Ultrastructual examination revealed cilia, microvilli and desmosomal junctions. The patient fully recovered after operation and showed no sign of recurrence after an year of follow-up. Clear cell ependymoma is a rare variant of ependymoma. Ultrastructual examination was more useful than immunohistochemical examination for diagnosis.

A 31-year-old woman with a history of spina bifida occulta became pregnant after ileocystoplasty for her neurogenic bladder. During the pregnancy she had frequent episodes of febrile urinary tract infections, and progressive hydronephrosis appeared in the second trimester. At 25 weeks gestation she was complicated by severe pyelonephritis requiring the intervention with the placement of double pigtail ureteral stent. However, long term efficacy of ureteral stent was questionable and this indwelling catheter caused bacteriuria which was not eradicated by intravenous antibiotics. Classical cesarean section was performed at 32 weeks of gestation due to the fear of fetal distress. Neobladder and mesenteric blood supply were adherent to the anterior surface of the uterus. Urinary tract infection is extremely common during pregnancy after enterocystoplasty. The most important point is prophylactic antibiotics throughout the pregnancy. At the time of cesarean section, a reconstructive urological surgeon should be part of the operative team and take great care to avoid injury to the blood supply of cystoplasty.

The early-onset type (onset earlier than 28 gestational weeks) of pregnancy induced hypertension (PIH) has the clinical characteristics of a high incidence of intrauterine growth retardations (IUGR), fetal distress, neonatal hypoglycemia and hypertensive disposition. Moreover, the infants from early-onset type of PIH mothers showed a statistically significant higher incidence of neurological handicap (cerebral palsy, mental retardation and epilepsy) than late onset type. The infants with a neurological handicap had severe IUGR and intractable hypoglycemia in the early neonatal period, probably due to low storage of glucose in the liver and fetal hypoxia. Appropriate perinatal management, including proper evaluation of fetal well-being and good timing of delivery, could improve the outcome of infants from early-onset type of PIH mothers.