Gene expression of metalloproteinases and their inhibitor in renal tissue of New Zealand black/white F1 mice

1. The present study was carried out to determine how levels of the mRNA of metalloproteinases (metalloproteinase-1, 72 kDa type IV collagenase, metalloproteinase-3 and 92 kDa type IV collagenase) and tissue inhibitor of metalloproteinases are regulated in the renal tissues of New Zealand Black/White F1 mice. 2. mRNA levels for metalloproteinase-1, 72 kDa type IV collagenase, metalloproteinase-3 and tissue inhibitor of metalloproteinases increased significantly with the progression of nephritis in New Zealand Black/White F1 mice. 3. At 48 weeks of age, the levels of mRNA for metalloproteinase-1, 72 kDa type IV collagenase, metalloproteinase-3 and tissue inhibitor of metalloproteinases increased by 8-, 4-, 8- and 15-fold, respectively, in the renal tissues of New Zealand Black/White F1 mice compared with New Zealand White mice. 4. In the kidneys of New Zealand White mice, however, the mRNA levels of these proteins changed little throughout the experimental period. 5. We could not detect expression of mRNA for 9 2 kDa type IV collagenase in the renal tissue of New Zealand Black/White F1 mice at 8 weeks of age or in New Zealand White mice at 8, 24 or 48 weeks of age, whereas we could detect expression of mRNA for this protein in New Zealand Black/White F1 mice at 24 and 48 weeks of age when mononuclear cells had infiltrated the interstitium and surrounding blood vessels. 6. At 24 weeks of age, New Zealand Black/White F1 mice were divided into two groups and received either methylprednisolone or saline injection for 24 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Allelic-expression imbalance of the insulin-like growth factor 2 gene in hepatocellular carcinoma and underlying disease

It has been well documented that the liver is an exceptional organ in which the monoallelic expression of insulin-like growth factor 2 (IGF2) due to genomic imprinting is relaxed during the postnatal period, resulting in biallelic expression thereafter. In the present study, changes in the status of genomic imprinting were examined in 15 hepatocellular carcinomas (HCCs) as well as in 29 liver biopsies of chronic hepatitis or liver cirrhosis without clinical evidence of HCC, following screening for heterozygotes with an ApaI polymorphism in IGF2 in 34 HCCs and 80 such non-HCC cases. Extreme allelic-expression imbalance, leading to restoration of monoallelic IGF2 expression, was observed in 15 (100%) of 15 informative HCCs for the polymorphism with this monoallelic IGF2 expression appearing to be non-random from the paternal allele. Interestingly, the same allelic-expression imbalance was also present in a significant fraction of noncancerous liver specimens of patients with underlying disease known to be associated with HCC development. In contrast, the status of genomic imprinting of H19, another gene closely mapped at 11p15 under opposite imprinting, was strictly maintained in seven (100%) of seven cases informative for an RsaI polymorphism of H19. Together with the previous reports on altered genomic imprinting of IGF2 and H19 in embryonal lesions such as Wilms tumors as well as in lung cancers, the results suggest that perturbations of imprinting status occur as locus and tumor-type specific events in the development of human cancers.     

Density wave v.s. magnetic breakdown: Mechanism of high-field phase transition in α-(BEDT-TTF)2XHg(SCN)4

We study the density wave instability under magnetic fields for the two-band two-dimensional electron system with the interband coupling due to the magnetic breakdown. We consider a model system having a pair of open Fermi surfaces and a closed Fermi surface, whose low-temperature state is a density wave phase caused by the nesting of open Fermi surfaces. Under the influence of magnetic fields, the density wave transition is suppressed by the magnetic breakdown coupling with the closed Fermi surface. We apply this model to the high-magnetic-field phase transition observed in the quasi-two-dimensiona1 organic conductors (BEDT-TTF)₂XHg(SCN)₄.     

Development of a parallel detection and processing system using a multidetector array for wave field restoration in scanning transmission electron microscopy

A parallel image detection and image processing system for scanning transmission electron microscopy was developed using a multidetector array consisting of a multianode photomultiplier tube arranged in an 8 x 8 square array. The system enables the taking of 64 images simultaneously from different scattered directions with a scanning time of 2.6 s. Using the 64 images, phase and amplitude contrast images of gold particles on an amorphous carbon thin film could be separately reconstructed by applying respective 8 shaped bandpass Fourier filters for each image and multiplying the phase and amplitude reconstructing factors.     

Creep mechanisms of a new Ni-Co-base disc superalloy at an intermediate temperature

The microstructures of a new Ni-Co-base disc superalloy, TMW-4M3, before and after the creep test at 725 °C/630 MPa have been systematically investigated by transmission electron microscopy (TEM). The crept microstructures were marked as three different deformation stages (I, II and III) corresponding to the gradually increased strain. At stage I, stacking fault (SF) shearing was the main deformation mechanism. The SF was extrinsic and lay on {111} plane. However, deformation microtwinning became the dominant mode at stage II and III. The average spacing of deformation twins decreased from 109 ± 15 nm at stage II to 76 ± 12 nm at stage III, whereas the twin thickness did not change significantly. The influence of stacking fault energy (SFE) of γ matrix on the deformation mechanism is discussed. It is suggested that lower SFE in TMW-4M3 is partly responsible for the enhanced creep resistance.     

Simultaneous characterization of acidic and basic properties of solid catalysts by a new TPD method and their correlation to reaction rates

We propose a new TPD method for simultaneously characterizing the acidic and basic properties of solid catalysts by utilizing the co-adsorption of NH₃ and CO₂ on catalysts. First CO₂ was adsorbed on the catalyst sample; then NH₃ was adsorbed on it. Another adsorption sequence of NH₃ and CO₂, and CO₂ and NH₃ single adsorptions were also conducted. The TPD measurements were carried out by heating the catalyst sample from 373 to 773 K at a heating rate of 2.5 K min⁻¹ in a helium stream under a total pressure of 1.3 kPa. In solid acid catalysts, there is little difference in the NH₃-TPD spectra between single and co-adsorption systems. This results from the absence of any induction effect between the acid and base sites, because the number of base sites in the solid acid catalyst is very small. In contrast, in a solid acid–base catalyst of alumina, a remarkable difference in the NH₃-TPD spectra was observed between single adsorption and co-adsorption systems. The difference in the TPD spectra between single and co-adsorption systems was ascribed to a strong induction effect appearing on the acid and base sites, which was proved by an in situ IR measurement. The validity of the TPD method was examined by correlating the number of the strong acid sites to catalytic activities of dehydrolysis of ethanol over solid acid and solid acid–base catalysts. In solid acid–base catalysts, the number of strong acid sites was calculated from the activation energy distribution for the desorption of NH₃ in a co-adsorption system because of the strong induction effect. A proportional relationship between the intrinsic reaction rate constant, which is based on the concentration of ethanol within the catalyst, and the number of strong acid sites could be obtained, regardless of the catalysts or their types or pore structure.     

Observation of ferroelectric domains in bismuth-layer-structured ferroelectrics using Raman spectroscopy

Raman spectroscopy has been used to investigate the domain structures in bismuth-layered-structured ferroelectrics (BLSFs). In Bi₄Ti₃O₁₂ single crystal, the lowest frequency mode (soft mode) at 30 cm⁻¹ appears exclusively for the xx polarization configuration (xpolar axis). We found that the polarization dependence of the Raman signal exhibits spatial symmetries that reflect the presence of different domain variants present in Bi₄Ti₃O₁₂. This highly anisotropic character of the soft mode shares with other BLSFs such as Bi_3.25La_0.75Ti₃O₁₂ and SrBi₂Ta₂O₉, which demonstrate the usefulness of the soft-mode spectroscopy for the study of ferroelectric domain structures in BLSFs. We also applied Raman spectroscopy to in situ observation of domain structures in Bi₄Ti₃O₁₂ under applied electric field.     

Raman spectra for β-FeSi2 bulk crystals

Complete determination of all Raman active lines in the range between 180 and 480 cm⁻¹ for an orthorhombic β-FeSi₂ lattice has been performed by accurate polarized Raman measurements on β-FeSi₂ and a crystal rotation method along the 〈111〉 axis. The 20 Raman active lines including 7 new lines in the range between 180 and 480 cm⁻¹ were observed. Further polarization relations for each observed Raman lines were analyzed from their intensity changes as a function of crystal rotation angle. The components of the Raman tensor of β-FeSi₂ were discerned from the polarization curves.     

微型金属注射成形制品质量的改善

本研究的目的是改善微型金属注射成形(μ-MIM)制品的质量。为此，研究着重于混练与注射成形的工艺。采用不同容量的三种型号混练机和二种型号注射机以制备混练料粒和微型哑铃形试样。测定了混练料粒的烧结密度和重量损失，也考虑了微型哑铃试样的烧结密度与强度。计算了每项性能的变动系数(CV)值，并讨论了均匀性。结果表明，较小的混炼机和注射机制造的试样，重量损失、烧结密度和强度的变化程度较小。     

Effect of loquat (Eriobotrya japonica) extracts on LDL oxidation

The antioxidative activity of the extracts of loquat fruits, Eriobotrya japonica Lindley was examined. Loquat fruit was separated into three parts (peel, flesh and seed), and each part was extracted with either water or ethanol. The extracts were then assessed for their free radical scavenging ability and effects on the oxidation of human low density lipoprotein (LDL) in vitro. Results in this study show that the ethanol extracts of all three loquat parts and the water extract of the peels exhibited a strong ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Among extracts of different loquat parts, the ethanol extract of loquat seeds was the most potent one. The ethanol extract of the seed was also effective in suppressing the oxidation of linoleic acid which was demonstrated by a slow discoloration of β-carotene/linoleic acid conjugation system. The ethanol extract of loquat seeds as compared to other extracts could also suppress significantly the 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN)-induced LDL oxidation. When the content of total polyphenolic compounds in different loquat parts (peel, flesh and seed) was examined, a significantly higher level of total polyphenols was found in the seed than the peels and flesh. Using reverse-phase HPLC-ESI EM analysis, significant levels of polyphenolic compounds such as chlorogenic acid, cyanidine glucoside, epicatechin, epigalocatechin gallate and procyanidin B₂ in the ethanol extract of different loquat parts were identified and quantified. The latter two compounds were found mainly in the ethanol extract of loquat seeds, but not in peels and flesh. Therefore, it is suggested that the high ability to scavenge free radicals and suppress the LDL oxidation exerted by the ethanol extract of loquat seeds was at least in part due to the high content of polyphenolic compounds in the seeds.