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Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio. [ABSTRACT FROM AUTHOR]

We describe a giant aneurysm of the anterior communicating artery (ACoA) which was treated with a STA-RA graft-A3 bonnet bypass and A3–A3 side-to-side anastomosis. A giant and partially thrombosed ACoA aneurysm was partially coated 3 years before his current presentation, its gradual increase producing visual field disturbances. An A3–A3 side-to-side anastomosis and STA-RA graft-A3 bonnet bypass were performed. The aneurysm was dissected, and the thrombus removed under transient parent-artery occlusion. The aneurysmal neck was successfully clipped without encountering ischemic changes. This strategy may be useful for treating giant or thrombosed aneurysms in the region of the ACoA. [ABSTRACT FROM AUTHOR]

In order to qualitatively and quantitatively analyze the structural defects including the defect types and their concentrations in oxide heteroepitaxial films, a new X-ray rocking-curve width-fitting method was used in the case of double CeO[SUB2]/YSZ/Si (YSZ = yttria-stabilized ZrO[SUB2]) films that were prepared by pulsed laser deposition. Two main defect types, angular rotation and oriented curvature, were found in both CeO[SUB2] and YSZ. Dislocation densities of CeO[SUB2] and YSZ, which were obtained from the angular rotations, are functions of the YSZ thickness. A distinct two-step correlation between dislocation densities of CeO[SUB2] and YSZ was found that as the dislocation density of YSZ is higher than 2.4 × 10[SUP11] cm[SUP-2], the dislocation density of CeO[SUB2] shows a high sensitivity with that of YSZ compared with the low relativity in lower dislocation density (< 2.4 × 10[SUP11] cm[SUP-2]). In addition, YSZ always has higher dislocation densities and oriented curvatures than CeO[SUP2] in each specimen, which can be attributed to the smaller mosaic domain sizes in YSZ than in CeO[SUP2] as observed by high-resolution transmission electron microscopy. [ABSTRACT FROM AUTHOR]

This study retrospectively assessed the parameters that affect pulse generator longevity in 78 patients implanted with dual-chamber pacemakers. Longevity was studied in 52 generators: 14 Cosmos II, 17 Relay, 11 Ellite II, and 10 Thera DR. The lifetimes of Cosmos II and Ellite II were significantly prolonged compared to those of Relay and Thera DR. The comparative study was conducted to evaluate the effect of low-impedance leads (ThinLine I, n = 10) on generator longevity compared with a standard lead (Irox, n = 16). No significant variation in pacing threshold was found between the groups. However, the low-impedance group provided significantly lower cell voltage and higher cell impedance during all follow-up periods compared with the standard lead impedance group. The internal current of the pacemaker with rate response and sophisticated diagnostic memory function (Relay, n = 5, and Marathon DR, n = 5) increased significantly compared with the conventional pacemaker (Cosmos II, n = 5). In conclusion, the selection of unnecessary pacing parameters and the selection of low-impedance leads should be avoided in order to extend generator longevity. [ABSTRACT FROM AUTHOR]

The Tokai Working Group on Cardiac Pacemakers was established in 1987 and initiated the Tokai Pacemaker Register in 1993. The register contains data on 1582 patients treated with 1582 generators and 2269 leads. The ECG indications for pacemaker implantation were 49.7% atrioventricular block, 41.1% sinus node dysfunction, and 7.4% atrial fibrillation. Dual-chamber pacing was used in 43.8%, VDD pacing was used in 37.6%, and single-chamber VVI pacing in 18.4% of the patients. [ABSTRACT FROM AUTHOR]

The structural correlations including the lattice constants and the mosaic dispersions between CeO[sub 2] and yttria-stabilized ZrO[sub 2] (YSZ) in CeO[sub 2] /YSZ/Si(001) heteroepitaxial films have been investigated by out-of-plane and in-plane X-ray-diffraction techniques. The distinct linear correlations of the full width at half-maximum (FWHM) of the ω scan between CeO[sub 2] and YSZ have been found in both directions. CeO[sub 2] always has a 0.7° lower FWHM of the ω scan than YSZ in the out-of-plane direction, but has a 2.6° higher FWHM in the in-plane direction. A possible relationship between the out-of-plane and in-plane FWHMs of the ω scans has been demonstrated with a lattice-rotation model. Besides, the lattice constants of CeO[sub 2] are dependent on the FWHMs of the YSZ ω scans: as the FWHM is below 3.5°, CeO[sub 2] has a tetragonal distortion, and as the FWHM is higher than 3.5°, CeO[sub 2] exhibits a cubic structure without distortion. The results are of great interest, both for the fundamental understanding of the film-growth mechanisms and for potential applications. [ABSTRACT FROM AUTHOR]

Objective and design: We evaluated the effectiveness of oral treatment with Japanese cedar pollen on experimental allergic rhinitis in guinea pigs.¶ Subjects: Male Hartley guinea pigs.¶ Treatment: From 16 days before the first sensitisation, 1 and 100 mg/time/animal pollen suspension was orally administered twice weekly. Animals were then sensitised and repeatedly challenged with the pollen.¶ Method: Guinea pigs were sensitised by intranasal instillation of cedar pollen extracts adsorbed onto Al(OH)3 at a dose of 0.3 μg pollen protein/0.3 mg Al(OH)3/3 μl/nostril twice a day for 7 days. Then the animal was challenged by inhalation with cedar pollen (1.8 mg/nostril) once every week. We evaluated the effects of the oral treatment with antigen on: 1) sneezing frequency, 2) nasal blockage after antigen challenge, 3) nasal hyperresponsiveness to histamine and leukotriene D4, and 4) titres of anaphylactic antibodies.¶ Results: During the course of the high dose administration, several animals died from a possible cytotoxicity, whereas the low dose caused no discernible change. The oral administration of the pollen at both the doses significantly inhibited nasal blockage, and the hyperresponsiveness to the stimuli was also strongly suppressed by the oral treatment. Inhibitory effectiveness did not differ substantially between the 1 and 100 mg/animal-treated groups. In contrast, neither sneezing frequency nor the increasing level of anaphylactic antibodies was influenced by the oral administration.¶ Conclusions: In this study, we found that the pollen-induced nasal blockage and hyperresponsiveness were suppressed by the oral administration of the pollen in the sensitised guinea pig. [ABSTRACT FROM AUTHOR]

Objective and design: We characterized the leukocyte kinetics after antigen challenge, and investigated the effects of the thromboxane (TX) A2 antagonist seratrodast, the peptide leukotriene (p-LT) antagonist pranlukast, the antihistaminic drug terfenadine and the glucocorticoid dexamethasone on this leukocyte response in a guinea pig model of allergic rhinitis.¶ Subjects: Male Hartley guinea pigs were used.¶ Treatment: Intranasally sensitized guinea pigs were challenged once every week for 15 weeks by inhalation of Japanese cedar pollen as the antigen. Dexamethasone and other agents were administered orally 3 and 1 h, respectively, before the 15th challenge.¶ Methods: The time-related changes in the numbers of differential leukocytes in nasal cavity lavage fluid (NCLF) and in peripheral blood after pollen inhalation challenge were investigated. The effects of the drugs on the antigen-induced changes in the leukocyte counts were evaluated. In addition, histopathological examination of the nasal mucosa was also performed 5 h after the challenge.¶ Results: There was a marked increase in the number of leukocytes in NCLF, especially of eosinophils, which peaked at 5 h, after antigen challenge in this model. This response was also accompanied by the peripheral blood eosinophilia and neutrophilia. Seratrodast (30 mg/kg), pranlukast (30 mg/kg) and dexamethasone (10 mg/kg) inhibited the eosinophilia in all of the blood, the nasal mucosa and NCLF seen 5 h after the antigen challenge. Terfenadine (10 mg/kg) had no apparent effect on the blood and the mucosal eosinophilia, although it tended to suppress the eosinophil accumulation in NCLF.¶ Conclusions: These results suggest that the present model is useful for analyzing the mechanisms of antigen-induced eosinophilic inflammation in allergic rhinitis and that both TXA2 and p-LTs, but not histamine, contribute to the antigen-induced eosinophilia in this model of allergic rhinitis. [ABSTRACT FROM AUTHOR]

Objective and design: We investigated the effects of the thromboxane (TX) A2 antagonist seratrodast, the peptide leukotriene (p-LT) antagonist pranlukast, the antihistaminic drug terfenadine and the glucocorticoid dexamethasone on antigen-induced sneezing, biphasic nasal blockage and nasal hyperresponsiveness to histamine using a guinea pig model of allergic rhinitis.¶ Subjects: Male Hartley guinea pigs were used.¶ Treatment: Intranasally sensitized guinea pigs were challenged once every week for 13 weeks by inhalation of Japanese cedar pollen as the antigen. Dexamethasone and other agents were administered orally 3 and 1 h, respectively, before the 4th, 6th and 13th challenge.¶ Methods: Sneezing frequency and the change in specific airway resistance (sRaw) were measured at these challenges. Two days after the 13th challenge, nasal responsiveness to histamine was evaluated by measuring sRaw after intranasal instillation of increasing doses of histamine. Moreover, the levels of TXB2, p-LTs and histamine were estimated in nasal cavity lavage fluid (NCLF) collected at the 13th challenge.¶ Results: Only terfenadine (10 mg/kg) significantly inhibited sneezing at any challenge time. Seratrodast (3 and 10 mg/ kg), pranlukast (30 mg/kg) and dexamethasone (10 mg/kg), but not terfenadine, suppressed both the early and late phase elevation of sRaw (biphasic nasal blockage), although the degree of inhibition on the early phase response varied with the challenge time. In contrast, the development of nasal hyperresponsiveness to histamine was inhibited by only dexamethasone. Furthermore, biphasic increases in TXB2, p-LTs and histamine in NCLF were observed after the challenge in sensitized animals.¶ Conclusions: These results suggest that TXA2 and p-LTs, but not histamine, play important roles in both the early and the late phase nasal blockage in this model of allergic rhinitis. [ABSTRACT FROM AUTHOR]

Three types of β-SiAlON (Si6 − z Al zO zN8 − z) powder were prepared by the carbothermal reduction and simultaneous nitridation of ultrafine powders in the Al2O3-SiO2 system. The ultrafine starting oxide powders, prepared using the vapour-phase reaction technique, were mixed with carbon powder and heated at 1400 °C for 1 h under flowing nitrogen to form β-SiAlON and followed by heating at 570 °C for 1 h in air to remove residual carbon. The resulting powders contained only β-SiAlON with z values of 1.63, 2.05, and 2.99. The relative density (bulk density/true density) of β-SiAlON compacts pressureless sintered at 1800 °C for 1 h under flowing nitrogen increased with z and reached 89.9% at z = 2.99. When the β-SiAlON compact with z = 2.99 was hot pressed at 1800 °C for 1 h under flowing nitrogen, a maximum relative density of 93.6% was achieved. Although this hot pressed compact contained a small amount of 15R-SiAlON in addition to β-SiAlON, it possessed a small average grain size (typically 0.5 μm diameter) and high Vickers hardness (19.2 GPa). [ABSTRACT FROM AUTHOR]

Steady state N2O decomposition reaction on polycrystalline Pt and Rh surfaces has been studied using a supersonic free jet molecular beam (2.1 × 1018 molecules/cm2 s). The energy of the incident N2O beam was controlled by a nozzle heating technique in conjunction with a seeding technique. The decomposition rate shows both translational and vibrational energy dependence on the Pt surface. However, there is also the surface temperature dependence of the decomposition rate even varying the incident beam energy, indicating precursor mediated dissociation of N2O on the Pt surface. On the other hand, no energy dependence was observed on the Rh surface, suggesting that the decomposition dynamics are different between Pt and Rh surfaces. [ABSTRACT FROM AUTHOR]

Objective and Design: We previously reported that oral l-ephedrine showed extraordinarily rapid inhibition of 48-h passive cutaneous anaphylaxis (PCA) in rats. In the present study, in vivo and in vitro experiments were performed to elucidate a possible mechanism for the inhibition.¶ Materials: Rat antiserum was prepared with dinitrophenylated Ascaris suum extract + Bordetella pertussis.¶ Treatment: Wistar rats were passively skin-sensitised, actively sensitised or non-sensitised. l-Ephedrine immediately before provocations was orally or intravenously administered in in vivo experiments. In in vitro experiments, the drug was added at various time and concentrations before the challenge.¶ Methods: The intensity of PCA was assessed by dye leakage method. Histamine and serotonin released in vitro or retained in the skin in vivo by anaphylaxis were assayed fluorometrically.¶ Results: Oral l-ephedrine rapidly inhibited the PCA by inhibiting the release of histamine and serotonin from the reaction site, whereas anaphylactic histamine and serotonin releases from skin fragments were not affected by the drug. Furthermore, the orally administered drug influenced neither the histamine- nor serotonin-induced cutaneous vascular permeability.¶ Conclusions: These results were strongly indicative that the prompt suppression of the PCA by oral l-ephedrine was not exerted following the drug was absorbed from the gastrointestinal tract. Thus, the result may be from an indirect inhibition of chemical mediator release, possibly through an unidentified stimulation of the nervous system, but not from the inhibition of chemical mediator release by the direct interaction of drug to mast cells and not from the decreased vascular permeability.¶ [ABSTRACT FROM AUTHOR]

The extent of the surface charge, that develops during oxidation of zirconia, is determined using work function measurements for both bulk specimen and thin films. The bulk specimen of yttria-doped zirconia (10 mol%) exhibits maxima of the surface electrical effect at 373 and 973 K (130 and 280 mV, respectively) that can be considered in terms of oxygen chemisorption and oxygen non-stoichiometry. Thin film of undoped zirconia exhibits a maximum at 473 K (260 eV). Addition of yttria (10 mol%) to the thin film results in a substantial reduction of the maximum, to about 140 eV, that is shifted up to 600 K. [ABSTRACT FROM AUTHOR]

The effects of a dopaminergic neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the amounts of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were examined in the whole brains of fetal mice and maternal mice after its administration to pregnant mice. DA and DOPAC concentrations were decreased significantly in both the fetal and maternal brains. At 3 hr after injection, reduction of the DOPAC concentration was more marked than that of DA in both the fetal and maternal brains. Increase of 5-HT concentration was observed until 12 hr after injection in the fetal brains and 6 hr in the maternal brains. These results indicate that 1-methyl-4-phenyl-pyridinium ion (MPP) and MPTP affect the levels of catechol- and indoleamines in the brain of premature stage as well as in the mature brain. [ABSTRACT FROM AUTHOR]

This paper reports surface electrical properties of zirconia studied using work function measurements in the temperature range 297-1173 K during oxidation. It was found that surface preparation procedures, such as grinding and polishing, result in a change of its reactivity with oxygen. The effects produced by the preparation can be removed during thermal treatment at 1473 K. [ABSTRACT FROM AUTHOR]

Dense spherical Ni particles were prepared from nitrate solution by spray pyrolysis in a H2–N2 atmosphere. Hollow NiO particles with rough surfaces were formed first at low temperature and then reduced to Ni by H2 above 300°C. Subsequent intraparticle sintering of the Ni crystallites gave rise to densification of Ni particles as the temperature was raised; most Ni particles became dense above the pyrolysis temperature of 1000°C. However, when a N2 atmosphere was used, hollow NiO particles were formed, which did not densify even at 1200°C due to the lack of sintering. The dense Ni particles obtained were of good crystallinity and good oxidation resistance, especially for those formed at higher pyrolysis temperatures and longer residence times. [ABSTRACT FROM AUTHOR]

Objective and Design: Development of nasal blockage and sneezing during repeated inhalation challenges with Japanese cedar pollens was evaluated in guinea pigs.¶ Subjects: Male Hartley guinea pigs.¶ Treatment: Guinea pigs were sensitized by intranasal instillation of cedar pollen extracts + Al(OH)3 2 times a day for 7 days. The animal was then forced to inhale the pollens for challenge, which was restrictively trapped in the upper airways, once a week.¶ Methods: Change of specific airway resistance (sRaw), sneezing frequency, and titers of anaphylactic antibodies in the serum were measured after each of the 30 challenges.¶ Results: At the first challenge, no obvious increase in sRaw was observed. However, the second and third challenges to the animals caused modest biphasic elevations of sRaw, with peaks at the first and the fourth to sixth hour. At the fourth to tenth challenges, marked elevations of sRaw were observed. However, with repetition of the inhalation challenge, the early and the late responses became almost indistinguishable because of partial overlapping as the responses expanded. All guinea pigs sneezed immediately after each pollen inhalation challenge. Apparent increases of both circulating γ1 and IgE antibodies were seen after the seventh challenge.¶ Conclusions: These results indicate that the experimental allergic rhinitis established in the present study can be a valuable model for analyzing the pathogenesis of the disease and developing new therapeutic drugs. [ABSTRACT FROM AUTHOR]

In Japan, hyperargininemia has been reported in only 5 unrelated families and four patients are alive at present. In this study we examined arginase protein in erythrocytes of these Japanese patients using two analytical methods of immunoblotting and two-dimensional gel electrophoresis. Immunoblotting study with anti-E. coli-expressed human liver arginase rabbit IgG revealed lack of cross-reacting materials in the erythrocyte lysates from these patients. On two-dimensional gels, arginase protein was detected in any control subject, but it was completely absent in all the patients studied. These results suggest that either arginase protein in erythrocytes is not produced or it is structurally labile in these patients. [ABSTRACT FROM AUTHOR]

In a patient with lysinuric protein intolerance, renal handling of lysine and arginine was examined to study the renal transport mechanism of this disease. The tubular reabsorption of lysine or arginine of the patient, when the filtered load of amino acid was increased by intravenous infusion, was not raised as much as that of control subjects at low filtered loads, but the ability for amino acid reabsorption seemed to exist under these conditions. However, when the filtered load was greatly increased, instead of a net reabsorption, a net secretion of amino acid was obtained. This seems to mean that at low filtered loads the amino acid in the tubular lumen is accumulated by the tubular cell across the intact luminal membrane, leading to a small amino acid excretion in the urine. With a great increase of the filtered load the saturated intracellular amino acid, which is not transported to the capillary because of a transport defect of the basolateral membrane, is assumed to leak back into the lumen. This causes a marked urinary amino acid loss exceeding filtered load at high tubular loads. The intravenous load of lysine depressed the percentage of arginine reabsorption and arginine load depressed lysine reabsorption. The percentage of the depressed amino acid reabsorption of the patient decreased almost linearly with increases of the inhibitor load. [ABSTRACT FROM AUTHOR]

Intravenous infusion of 0.5 mmol/kg L-lysine monohydrochloride was performed in six normal volunteer subjects aged 10-14 years to study the inhibitory effect of lysine on urea cycle metabolism. The lysine infusion resulted in a significant increase in plasma levels of arginine and ornithine, and in urinary homocitrulline, putrescine, and orotic acid, accompanied by a significant increase in blood ammonia. There was little change in plasma urea and citrulline. The increase in plasma arginine appears to reflect an inhibited arginase activity although the plasma urea level did not change. The increased homocitrulline excretion suggests that ornithine conversion to citrulline via ornithine transcarbamylase (OTC) was inhibited. The simultaneous increase in plasma ornithine and urinary putrescine may reflect an inhibition of mitochondrial ornithine transport. In addition to the direct ammoniagenic property of lysine, impaired ornithine conversion to citrulline resulting from the inhibition of both OTC activity and mitochondrial ornithine uptake by lysine may be responsible for the increase in blood ammonia and urinary orotic acid. Despite the retarded citrulline formation, a promoted efflux of citrulline from mitochondria may have kept the plasma citrulline level unchanged. [ABSTRACT FROM AUTHOR]