Prospective study of the detection of anomalous connections of pancreatobiliary ducts during routine medical examinations

BACKGROUND/AIMS: It is important to achieve detection of of anomalous connections of the pancreatobiliary ducts (ACPBD), because this condition often leads to pancreatobiliary disease. The present prospective investigation focused on revealing the incidence of ACPBD in asymptomatic individuals undergoing medical checkups. MATERIAL AND METHODS: Extracorporeal ultrasonography (US) was performed on all asymptomatic individuals undergoing medical checkups. Identification by abdominal ultrasonography of 3 mm or more gallbladder wall thickening, or 10 mm or more dilatation of the bile duct were considered indicative of ACPBD and endoscopic ultrasonography (EUS) was carried out in selected cases. Endoscopic retrograde cholangiopancreatography (ERCP) was then performed to confirm the existence of ACPBD. RESULTS: The overall incidence of ACPBD was 0.03% (9/27,076 subjects). ACPBD was found in 23% of cases with bile duct dilatation, and in 2.9% with gallbladder wall thickening. CONCLUSION: ACPBD was not as rare a disease as expected. For early detection of ACPBD, identification by abdominal ultrasonography of gallbladder wall thickening or dilatation of the bile duct are indicative. Patients who are suspected of having this abnormality should then undergo EUS. The final diagnosis should then be made by ERCP.     

Radiation-induced reactions of ring-substituted polystyrenes analyzed by radiolysis of low molecular-weight model compounds

Radiation-induced reactions of polystyrene derivatives have been studied by the radiolysis of ring-substituted isopropylbenzene derivatives, i. e., 4-amino. 4-hydroxy, 4-methoxy, 4-methyl, 4-chloromethyl, 4-chloro, and 4-acetyl derivatives. Low-temperature ESR analyses measured at 77 K indicate that. In general, the a-position is the most sensitive site to radiation and that thus a-radicals are produced through a-hydrogen removal. However, among these derivatives, the amino, acetyl, chloromethyl, and. chloro derivatives undergo different reactions from the other derivatives. A phCO? CH₃ cleavage from the- acetyl derivative and N? H cleavage from the amino derivative occur, and chlorine removal takes place from the chloro-methyl and chloro derivatives. Final products detected by gas chromatography-mass spectrometry indicate not only that radiation-induced free radical recombination occurs. but also that if chlorine is produced by radiation, hydrogen abstraction by radiation-induced chlorine takes place prior to the free radical recombination. The susceptibility of each derivative to hydrogen abstraction by radiation-induced active chlorine increases, as the electron-donation of ring-substituents is increased. Based on the clarified reaction mechanism, the design of polystyrene derivatives as resist materials is discussed and two new types of resist systems are described. One is a new chloromethylstyrene based blend resist, which is formulated from poly(4-meth-oxystyrene) and poly(4-chloromethylstyrene). The other is a new non-swelling alkaline developable negative resist, which is formulated from poly(4-hydroxystyrene) and a chlorine-releasing compound.     

Efficiency enhancement in a Cherenkov laser loaded with a Kerr-likemedium

Efficiency enhancement in energy conversion for a Cherenkov free elctron laser loaded with a Kerr-like medium is discussed with the aid of particle simulation. For the analysis of the problem, a two-dimensional model for the Cherenkov free electron laser is considered which is composed of a planar relativistic electron beam and a parallel plate waveguide one plate of which is loaded with a nonlinear dielectric sheet exhibiting a Kerr-like effect. To follow the growth of an electromagnetic wave and the decrease in the kinetic energy of the electron beam in the specified model of the Cherenkov free electron laser, a particular segment of the electron beam with the longitudinal length of one guide wavelength is picked out. In that segment, as it travels down the waveguide, the interaction between the electromagnetic wave and a group of electrons is analyzed with the use of the finite-difference time-domain (FDTD) method. The result of numerical simulation shows that the efficiency of energy transfer from the electron beam to the electromagnetic wave is greatly enhanced by the proper choice of the nonlinear parameter for a Kerr-like medium. The enhanced efficiency is due to the improved velocity matching between the electron beam and the electromagnetic wave, and to the self-focusing effect of a Kerr-like medium     

Kinetic analysis of tetraethylammonium transport in the kidney epithelial cell line, LLC-PK1

PURPOSE: The aims of this study were to establish a kinetic means of analyzing the membrane transport of organic cations in renal epithelial cells, and to simultaneously evaluate drug interactions in apical and basolateral membranes. METHODS: Tetraethylammonium (TEA) transport was measured using LLC-PK1 cell monolayers grown on microporous membrane filters. After incubating the cells with unlabeled TEA or other drugs, apical or basolateral medium was changed to that containing labeled TEA, and transcellular transport and cellular accumulation were measured. Clearance from apical medium to cells (CL12), cells to apical medium (CL21), cells to basolateral medium (CL23) and basolateral medium to cells (CL32) were calculated based on a three compartment model. RESULTS: TEA was accumulated progressively in the monolayers from the basolateral side and was transported unidirectionally to the apical side. CL32 was greater than CL12 and CL23 was greater than CL21. Therefore, the rate limiting step of TEA transport from the basolateral to the apical medium was the cell-to-apical step. Co-incubation of TEA with procainamide decreased the transport parameters of TEA, CL12, CL21 and CL32, whereas that with levofloxacin decreased only CL12 and CL21, not affecting the parameters in basolateral membranes. CONCLUSIONS: Using a simple model, we analyzed the transport of organic cation in kidney epithelial cell line, LLC-PK1. This method can be useful for the analysis of cation transport and drug interactions in the apical and basolateral membranes of renal tubules.     

Decomposition of nitric oxide on metallosilicates under a large excess oxygen condition with coexistence of a low concentration cetane

Catalytic removal of NO was conducted under the condition of large excess O₂ by using different kinds of metallosilicates having MFI structure. With coexistence of a low concentration of cetane, H-Fe-silicate, which had both acidity and redox property, exhibited the maximum performance among the catalysts tested at a fairly lower temperature range, around 350 °C, and the NO was totally converted. The temperature dependence of NO conversion was consistently similar to that of cetane combustion.     

Solvothermal syntheses of semiconductor photocatalysts of ultra-high activities

Thermal treatment of titanium(IV) butoxide dissolved in 2-butanol at 573 K under autogenous pressure (alcohothermal treatment) yielded microcrystalline anatase-type titanium(IV) oxide (TiO₂). Thermal treatment of oxobis(2,4-pentanedionato-O,O′)titanium (TiO(acac)₂) in ethylene glycol (EG) in the presence of sodium acetate and a small amount of water at 573 K yielded microcrystalline brookite-type TiO₂. Tungsten(VI) oxide (WO₃) powders of monoclinic crystal structure with high crystallinity were synthesized by hydrothermal treatment (HTT), at 523 or 573 K, of aqueous tungstic acid (H₂WO₄) solutions prepared from sodium tungstate by ion-exchange (IE) with a proton-type resin. Anatase and brookite TiO₂ products were calcined at various temperatures and then used for photocatalytic mineralization of acetic acid in aqueous solutions under aerated conditions and dehydrogenation of 2-propanol under deaerated conditions. Almost all the anatase-type TiO₂ samples showed the activities more than twice higher than those of representative active photocatalysts, Degussa P-25 and Ishihara ST-01 in both reactions. A brookite sample with improved crystallinity and sufficient surface area obtained by calcination at 973 K exhibited the hydrogen evolution rate almost equal to P-25. HTT WO₃ powders with various physical properties were used as photocatalyst for evolution of oxygen (O₂) from an aqueous silver sulfate solution. WO₃ powder of high crystallinity, e.g., IE-HTT-WO₃ synthesized at 573 K, gave much higher O₂ yield than commercially available WO₃ samples.