K(ATP) channels contribute to the cardioprotection of preconditioning independent of anaesthetics in rabbit hearts

The contribution of ATP sensitive potassium (K(ATP)) channels to the infarct-size limiting effect of preconditioning is considered to be anaesthetic-dependent in the rabbit heart. It has previously been reported that ischaemic preconditioning prevents ischaemia-induced reductions in activities of sarcolemmal adenylate cyclase (AC) and Na+, K(+)-ATPase. Anaesthetic dependency of the role of K(ATP) channels in the preservation of these enzyme activities, induced by ischaemic preconditioning, as well as that induced by activation of A1-adenosine receptors, was examined in rabbits anaesthetized with either pentobarbital or ketamine-xylazine and subjected to 20 min of regional ischaemia. Adenylate cyclase and Na+, K(+)-ATPase activities were lower in the ischaemic than in the non-ischaemic region of the hearts in control rabbits, but not in animals subjected to ischaemic preconditioning, or those pretreated with the A1-adenosine receptor agonist R(-)-N6-(2-phenylisopropyl) adenosine. The protective effects of both ischaemic preconditioning and A1-adenosine receptor activation were prevented by 6 mg/kg, but not 3 mg/kg, of the K(ATP) channel blocker, glibenclamide, in rabbits anaesthetized with pentobarbital, while these effects were prevented by 3 mg/kg of the blocker in rabbits anaesthetized with ketamine-xylazine. Moreover, K(ATP) channel opener, cromakalim, prevented the ischaemia-induced decreases in enzymatic activities in rabbits subjected to either type of anaesthesia. Thus, although the antagonistic effect of glibenclamide is blunted under pentobarbital, compared to ketamine-xylazine anaesthesia, K(ATP) channels contribute to preservative actions independent of the type of anaesthesia in the rabbit heart.     

Effect of grain size on creep of Ti-53.4mol%Al intermetallics at 1100 K

Constant stress creep under compression stress, 100 to 316 MPa, at 1100 K was investigated on single-phase TiAl intermetallics. The material was ingot-cast, isothermally forged, and then annealed to produce stable equi-axed grain structures, whose average grain diameters were 25, 42 and 70m. Creep curves were very similar among the three specimens with different grain diameters and the creep rates at a given strain, as well as the minimum creep rates, depended little on grain size. Two regimes were observed on the stress dependence of the minimum creep rate. The stress exponent under high stresses was about 4.5, independent of grain size. Under stresses lower than about 150 MPa it became about 8.     

Phase structure in the blend of atactic poly(vinyl alcohol) with atactic poly(vinyl alcohol‐block‐vinyl acetate)

An almost fully saponified atactic poly(vinyl alcohol) and an atactic poly(vinyl alcohol‐block‐vinyl acetate) of which degree of saponification is 89 mol % were blended by a solution casting method. The phase structure of the blend film was analyzed by optical microscopy, ¹³C‐NMR, and differential scanning calorimetry. The most remarkable structure of the blend was composed of cylindrical domains penetrating the film. The swelling behavior of the blend films was also investigated in the dimethylsulfoxide and water mixed solvents to find differences in solubility and diffusion behavior between the matrix and the domain. The cylindrical domains could be selectively dissolved away in water and the film became porous. We tried to change the size of the cylindrical domain with various film preparation conditions. This aimed to turn the film into the useful filter membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1807–1815, 2002     

The Crystal and Molecular Structure of Ethyl p-Chloro α-Cyano-β-Methyl-Cis-Cinnamate,C13H12No2Cl

Crystals of ethyl p-chloro α-cyano-β-methyl-cis-cinnamate, C₁₃H₁₂NO₂Cl, are orthorhombic, space group Pbcn, with eight molecules per unit cell, a = 17.31, b = 8.68 and c = 17.20 Å. The structure was solved by direct methods and refined subsequently by Fourier techniques. The benzene ring makes a dihedral angle of 60.0° with the ethylenic group. This suggests significant steric effects of the β-methyl group and of the carbonyl group on the orientation of the benzene ring. The conformation of the ethylene bond and the carbonyl group around the C_α? C bond is roughly cisoid and the angle of twist is 16.5°. Nearest-neighbour >C = C <groups make contact across a two-fold axis at a center-to-center distance of 4.33 Å.     

Systematic analysis of glycosphingolipids in the human gastrointestinal tract: Enrichment of sulfatides with hydroxylated longer-chain fatty acids in the gastric and duodenal mucosa

The composition of the glycosphingolipids of the human gastrointestinal tract was studied. The major neutral glycosphingolipids were ceramide monohexosides (e.g., GalCer, GlcCer), LacCer, Gb₃Cer, Gb₄Cer and more polar ones with more than four sugars, whereas neither Gg₃Cer nor Gg₄Cer were present. The acidic glycosphingolipids consisted of sulfatides and gangliosides such as G_M3, G_M1, G_D3 and G_D1a. Also a large amount of sulfatides was found in the gastric mucosa and duodenum. The concentrations of sulfatides in the fundic mucosa, antral mucosa and duodenum amounted to 416.0, 933.8 and 682.9 nmol/g of dry weight, respectively, exceeding those in the gastric mucosa and kidney of other mammals. The major molecular species of the sulfatides were identified as I³SO₃-GalCer with hydroxylated longer-chain fatty acids based on the analyses by gas-liquid chromatography and negative ion fast-atom bombardment mass spectrometry. In contrast, gangliosides in these regions showed a tendency to be lower than sulfatides, and the molar ratios of sulfatides to gangliosides were about 2.0, whereas those in other parts were less than 0.5. A high content of sulfatides in the gastric and duodenal mucosa, where mucosa is easily insulted by acid, pepsin and bile salts, may be closely related to their roles in mucosal protection. The nomenclature used for gangliosides and other glycosphingolipids follows the system of Svennerholm (Ref. 1) and the recommendation of the IUPAC-IUB Commission (Ref. 2), respectively.     

Validation of Platelet Counting Accuracy With the Celltac F Automated Hematology Analyzer

Rapid and accurate analysis of platelet count plays an important role in evaluating hemorrhagic status. Therefore, we evaluated platelet counting performance of a hematology analyzer, Celltac F (MEK-8222, Nihon Kohden Corporation, Tokyo, Japan), that features easy use with low reagent consumption and high throughput while occupying minimal space in the clinical laboratory. All blood samples were anticoagulated with dipotassium ethylenediaminetetraacetic acid (EDTA-2K). The samples were stored at room temperature (18^{^}C–22^{^}C) and tested within 4 hours of phlebotomy. We evaluated the counting ability of the Celltac F hematology analyzer by comparing it with the platelet counts obtained by the flow cytometry method that ISLH and ICSH recommended, and also the manual visual method by Unopette (Becton Dickinson Vacutainer Systems). The ICSH/ISLH reference method is based on the fact that platelets can be stained with monoclonal antibodies to CD41 and/or CD61. The dilution ratio was optimized after the precision, coincidence events, and debris counts were confirmed by the reference method. Good correlation of platelet count between the Celltac F and the ICSH/ISLH reference method (r = 0.99, and the manual visual method (r= 0.93) were obtained. The regressions were y = 0.90 x+9.0 and y=1.11x+8.4, respectively. We conclude that the Celltac F hematology analyzer for platelet counting was well suited to the ICSH/ISLH reference method for rapidness and reliability.     

Preparation of Aluminum Nitride Powder from Aluminum Polynuclear Complexes

AIN powder was synthesized from aluminum polynuclear complexes. Basic aluminum chloride and basic aluminum lactate were used as the aluminum polynuclear complexes. These starting materials and glucose were dissolved in water and mixed homogeneously. AIN powder was obtained by calcining after drying and precalcining at 800°C under nitrogen gas flow. Then excess carbon was removed by firing in air. Nitridation in the system was investigated and compared with that in the alumina–carbon black system. It was found that in our reaction system nitridation began and proceeded at lower calcination temperatures above 1200°C than in the alumina–carbon black system. Using aluminum polynuclear complexes, AIN was synthesized through the nitridation of γ-alumina and produced in a very fine and sharp particle size distribution.     

Melt viscosity and flow birefringence of polycarbonate

Melt viscosity and flow birefringence of bisphenol A-type polycarbonate were measured and analyzed by the application of rubber-like photoelastic theory. The melt viscosity in the Newtonian flow region increased with the molecular weight to the power of 3.4. In polycarbonate, the shear stress of the Newtonian flow region was to 10⁶ dyn/cm², whereas in PMMA it was at most 3 = 10⁵ dyn/cm². The flow birefringence δn has a linear relation with shear stress S, that is δn = 5.7 × 10^?10 S. The principal polarization difference of flow unit α₁ – α₂ was 1.62 × 10^?23 cm³, which was obtained by the application of the rubber-like elastic theory. In PMMA, it was 3.9 = 10^?25 cm³; about 1/40 of that was polycarbonate. The anisotropy of polarizability of the flow unit of polycarbonate was also about 40 times larger than that of PMMA. So the anisotropy reflected the large flow birefringence of the polycarbonate.