Liver phosphatidylcholine hydroperoxidation provoked by ethionine-containing choline-deficient diet in mice

It is shown that peroxidation of phosphatidylcholine (PC) is enhanced in liver of mice fed a hepatocarcinogenic choline-deficient diet containing 0.1% w/w ethionine. Mice were divided into 4 groups and fed for 3 weeks one of the following diets: choline-supplemented; choline-supplemented containing ethionine; choline-deficient; and choline-deficient containing ethionine. Phosphatidylcholine hydroperoxide (PCOOH) of liver lipids was measured by high performance liquid chromatography using a chemiluminescence detector. Mice fed a choline-deficient diet containing ethionine showed 6-fold higher PCOOH levels than the choline-supplemented control mice: the PCOOH/PC molar ratios of liver lipids were 32.3×10⁻⁵ and 5.6×10⁻⁵, respectively. In addition to this remarkable degree of lipid peroxidation in liver of mice fed the choline-deficient diet containing ethionine, we also observed a significant liver fatty infiltration, a decrease in plasma and liver α-tocopherol, and an increase in liver injury-indicative enzyme activities. Also, marker enzymes for hepatocarcinogenesis, glucose-6-phosphatase and γ-glutamyl transpeptidase were affected. These data suggest that enhanced hydroperoxidation of phosphatidylcholine may participate in hepatocarcinogenesis provoked by choline deficiency in the presence of ethionine.     

Microstructure Development and Dielectric Properties of Potassium Strontium Niobate Ceramics

Sintering of a KSr₂Nb₅O₁₅ powder compact at 1350°C resulted in a duplex structure. Prefiring of the compact between 1200° and 1300°C inhibited the abnormal grain growth responsible for the duplex structure. The Curie temperature and dielectric constant were dependent on the microstructure.     

Preparation of Ba2YCu3O7-δ Thin Films with Preferred Orientation through an Organometallic Route

Superconducting Ba₂YCu₃O_7-δ thin films were prepared through an organometallic route. Single-phase Ba₂YCu₃O_7-δ thin films with preferred orientation were successfully prepared on SrTiO₃ (100) single-crystal substrates at 800°C by a dip coating method using partially hydrolyzed Ba-Y-Cu organometallic solutions. Preferentially oriented Ba₂YCu₃-O_7-δ thin films were also prepared on MgO (100) substrates. By controlling the partial hydrolysis conditions, a coating solution for precursor thin films was kept accurately at the stoichiometric composition. The use of ozone gas during the pyrolysis of the precursor thin films was found to suppress the formation of BaCO₃. Ba₂YCu₃O_7-δ thin films with c -axis orientation perpendicular to a SrTiO₃ (100) substrate, which were heat-treated at 900°C for 15 min, exhibited a superconductivity transition with an onset of 90 K and an end of 75 K.     

Capillary gas-liquid chromatographic separation of oxo and oxo-hydroxy bile acid isomers of theallo and normal series

Capillary gas-liquid chromatographic separation was studied for 60 oxo and oxo-hydroxy bile acids of theallo (5α-H, A/B-trans) and normal (5β-H, A/B-cis) series, which differ from one another in the number, position, and configuration of oxo and hydroxy groups at positions C−3, C−4, C−6, C−7, and/or C−12. Good separation of the isomers was achieved by the use of an aluminum-clad fused-silica capillary column coated with bonded and cross-linked methyl polysiloxane.     

Effect of green compact structure on the sintering of alumina

The effect of particle agglomeration on sintering has been studied by slipcasting suspensions with pH values ranging from 2 to 11. The rate of densification has been found to depend on the degree of agglomeration. Complete dispersion of alumina primary particles has not been attained through adjustment of pH of suspensions, and agglomerates also remained in the best-dispersed suspension. Elimination of the agglomerates by sedimentation lowered the densification temperature of slip-cast compacts. The grain size-density curve is a function of temperature. High-density and small-grained sintered bodies were obtained by low-temperature long-time firing.     

Contrasting effects of water-soluble and water-insoluble dietary fibers on bile acid conjugation and taurine metabolism in the rat

The effect of the type of dietary fiber on the bile acid and taurine metabolism was examined in rats. Diets containing 10% of various water-soluble fibers (citrus pectin, konjak mannan, guar gum) as compared to a fiber-free diet increased biliary excretion of total bile acids. In contrast, water-insoluble dietary fibers (cellulose, corn bran, chitin; 10% in the diets) as well as cholestyramine (5% in the diet) considerably, decreased bile acid excretion. Water-soluble dietary fibermediated increases in bile acid excretion were totally attributable to increases in glycine-conjugates. Thus, these fibers greatly increased by the bile acid glycine-to-taurine ratio (G/T). Excretio of glycine conjugates decreased more than that of taurine conjugates in rats fed various water-insoluble dietary fibers. As a results, G/T in rats fed water-insoluble fibers was significantly lowered as compared to G/T in animals fed a fiber-free diet. Cholestyramine did not affect the G/T ratio of bile acids. Fecal bile acid excretion and the activities of hepatic cholesterol 7α-hydroxylase (EC 1.14.13.17) in rats fed various water-soluble dietary fibers approximately doubled as compared to the respective values for rats fed a fiber-free diet. Whereas cholestyramine greatly increased these parameters, water-insoluble fibers did not significantly affect them. Various water-soluble fibers decreased hepatic concentration and urinary excretion of taurine as well as the activity of hepatic cysteine dioxygenase (EC 1.13.11.20). In contrast, water-insoluble fibers considerably increased hepatic taurine concentrations and enzyme activities. The parameters for taurine metabolism were unaffected by cholestyramine. It was suggested that the types of dietary fiber affected hepatic taurine synthesis and thus modified bile acid glycine/taurine ratios.     

Diagnosis and treatment of tumours in the pineal region

In a series of 3.072 cases of intracranial neoplasms up to the end of 1973 there were 82 tumours in the pineal region (2.7%), excluding meningiomas of the falx and tentorium. More than half (forty seven) were pinealomas (two cell pattern type tumours, and pineoblastomas), twelve were teratomas, eight were ependymomas, three were epidermoids, and the remainder were gliomas. In addition to ventriculography, millipore filter-cell culture of cerebrospinal fluid, and fibre ventriculoscopy were found useful for diagnosis. Most of the patients were treated by surgery followed by radiotherapy. Results with the pinealomas were fairly good, the one year, five year, and ten year survival rates being 87.5%, 71.4%, and 33.3% in those below the age of 15 years, and 80.0%, 46.2%, and 12.5% in those above that age. The radiosensitivity of pinealomas and the beneficial effect of reduction of tumour bulk by direct surgery may both be important factors in the achievement of good results.     

The MHD effect and its relaxation process on electric current in the electrolysis of ferricyanide reduction and ferrocyanide oxidation

The electrolytic reduction of ferricyanide and the electrolytic oxidation of ferrocyanide have been carried out with exposing the magnetic field of 1000 or 1800 gauss. The current clearly increased after the magnetic exposure. The maximum current was obtained when the magnetic flux directed in parallel with the surface of electrode. These are speculated in terms of magnetohydrodynamic mechanism. The current decrease caused by relaxation process was observed after the removal of magnetic flux. The relaxation time obtained was temperature-dependent. Therefore the values of apparent transition energy, E_trans, were determined from the Arrhenius' plots of relaxation time against temperature. The magnitude of E_trans was dependent on the concentration of ferricyanide or ferrocyanide, and the viscosity and the conductivity of electrolyte solution. The activation energy of viscosity of electrolyte solution was compared with E_trans. As a conclusion, it was suggested that E_trans may be influenced by the velocity of magnetohydrodynamic flow, which was controlled by the diffusion current in electrolysis and the viscosity of electrolyte solution.     

Distribution of double bonds in thermally degraded polyisobutylene

The distribution of double bonds in thermally degraded polyisobutylene was determined quantitatively by using pulsed Fourier transform ¹H n.m.r. spectroscopic analysis. The double bonds in the degraded polymer did not exist in the interior but at the terminal positions of the polymer chain. These olefins were of the terminal trisubstituted and terminal vinylidene types. The content of the former was much greater than that of the latter. This shows that radical chain transfer predominantly occurs at the methylene hydrogen rather than at the methyl groups of the polymer chain. The average number of double bonds per molecule, f, was greater than 1 and tended to be near 2. Thereby most of the degraded polyisobutylene was shown to have two terminal unsaturations per molecule.     

Synthesis of tetramethyl-p-silphenylenesiloxanedimethylsiloxane triblock copolymer by employing living anionic polymerization

Dimethylsiloxane-tetramethyl-p-silphenylenesiloxane-dimethylsiloxane (DMS-TMPS-DMS) triblock copolymer was synthesized by employing living anionic polymerization of hexamethylcyclotrisiloxane (D₃). Two synthetic methods were carried out for the polymerization. One of those methods was the anionic polymerization of D₃ initiated at the silanolate anion which was prepared from the terminal hydroxyl group of silanol-terminated TMPS prepolymer by reaction with n-butyllithium (method 1). The other was the coupling reaction of vinyl-terminated TMPS prepolymer with hydrosilyl-terminated DMS prepolymer obtained from the anionic polymerization of D₃ by using diphenylmethylsilanolate anion as initiator (method 2). In method 1, DMS contents of the copolymers ranged from 25.8 to 72.5 wt% and the values agreed with the ratio of D₃ to TMPS prepolymer. The weight-average molecular weights ranged from 1.36×10⁴ to 19.4×10⁴ and were close to the predicted values calculated from the $\text{M}\text{?}{}_{\mathrm{v}}$ of the TMPS prepolymer and the amount of D₃ added. In the case of method 2, weight-average molecular weights ranged from 19.5×10⁴ to 24.2×10⁴. The high molecular weight copolymer could thus be obtained by method 2. Intrinsic viscosity values of the triblock copolymers agreed with calculated values obtained by considering the copolymer as a binary mixture of these homopolymers. Differential scanning calorimetry and thermogravimetry were carried out on the triblock copolymers. The equilibrium melting temperatures of each of the copolymers were very close to that of poly-TMPS (160°C). The glass transition temperature and heat of fusion were decreased as the DMS content was increased. The thermogravimetric curves for the copolymers indicated that the thermal stability of the triblock copolymer was intermediate between the DMS and TMPS homopolymers.