Age-related changes in the metabolism of acetylated low-density lipoproteins by peritoneal macrophages from C57BL/6CrScl mice

Macrophages are major precursors of foam cells in atherosclerotic lesions. Acetylated low-density lipoproteins (acetyl LDL) taken up by macrophages through scavenger receptors are degraded by lysosomes and the released cholesterol is re-esterified, leading to foam cell formation. The ability of resident peritoneal macrophages from C57BL/6CrScl mice to form foam cells in relation to the donor age was assessed by the cholesterol esterification and the metabolism of acetyl LDL. The incorporation of 14C-oleate (complexed to albumin) into cellular cholesteryl esters in the presence of acetyl LDL (100 micrograms/ml) was significantly greater in macrophages from senescent mice (24-25 months) than in cells from young (3-4 months) mice (p < .001). The degradation and cellular association of acetyl LDL by macrophages from senescent mice were significantly greater than macrophages from mature mice, (p < .001 and p < .01, respectively), whereas the binding of acetyl LDL was similar in peritoneal macrophages from mature and senescent mice. These results suggest that the uptake and degradation of acetyl LDL, and the re-esterification by macrophages increase with advancing age and that the ability of macrophages to form foam cells increases with aging. The enhanced ability of senescent macrophages to form foam cells might contribute to the development and progression of atherosclerosis related to the aging process.     

Malignant lymphoma of the testis: report of two cases

Two cases on non-Hodgkin's malignant lymphoma (NHL) of the testis are reported. A 63-year-old man with left painless scrotal swelling underwent orchiectomy. Although prophylactic irradiation was performed under the diagnosis of seminoma, subsequent immunohistochemistry revealed NHL, large diffuse cell type (B type). He had stage IEA disease. Chemotherapy with cyclophosphamide, adriamycin vincristine and prednisolone was performed. The second case was in a 63-year old man with right painless scrotal swelling. Orchiectomy revealed NHL, diffuse medium cell type (B type). Because of tumor in the retrosternum, he had stage IIIEA disease. Chemotherapy and irradiation to the contralateral testis was performed.     

Rapid preparation of monodisperse biodegradable polymer nanospheres using a membrane emulsification technique under low gas pressure

Nanospheres of poly(lactide-co-glycolide) (PLGA), a biodegradable polymer, have been prepared using the conventional solvent diffusion method. In this study, a method combining the solvent diffusion method and a two-step (premix) membrane emulsification technique is proposed for the preparation of monodisperse PLGA nanospheres with a diameter of 200 nm. The monodispersity of the PLGA nanospheres was higher than that of nanospheres obtained by the conventional solvent diffusion method. Generally, preparation of small particles or droplets by the membrane emulsification technique requires a supply of high-pressure nitrogen gas to force the emulsion or dispersion solution through the small pores of the membrane. However, in the technique proposed here, low-pressure nitrogen gas (0.02–0.11 kgf/cm²) is sufficient. Thus, using this technique, one can obtain monodisperse PLGA nanospheres with a diameter of 200 nm in a relatively short period of time under low-pressure nitrogen gas.     

Effect of surface roughness and surface modification of indium tin oxide electrode on its potential response to tryptophan

The effect of surface modification of indium tin oxide (ITO) electrode on its potential response to tryptophan was investigated for ITO substrates with different surface roughness. It was found that a small difference in surface roughness, between ∼1 and ∼2 nm of R_a evaluated by atomic force microscopy, affects the rest potential of ITO electrode in the electrolyte. A slight difference in In:Sn ratio at the near surface of the ITO substrates, measured by angle-resolved X-ray photoelectron spectrometry and Auger electron spectroscopy is remarkable, and considered to relate with surface roughness. Interestingly, successive modification of the ITO surface with aminopropylsilane and disuccinimidyl suberate, of which essentiality to the potential response to indole compounds we previously reported, improved the stability of the rest potential and enabled the electrodes to respond to tryptophan in case of specimens with R_a values ranging between ∼2 and ∼3 nm but not for those with R_a of ∼1 nm. It was suggested that there are optimum values of effective work function of ITO for specific potential response to tryptophan, which can be obtained by the successive modification of ITO surface.     

Styrene–butadiene rubber/cellulose II/clay nanocomposites prepared by cocoagulation—mechanical properties

In this work, nanocomposites of styrene butadiene rubber (SBR), cellulose II, and clay were prepared by cocoagulation of SBR latex, cellulose xanthate, and clay aqueous suspension mixtures. The incorporated amount of cellulose II was 15 phr, and the clay varied from 0 to 7 phr. The influence of cellulose II and clay was investigated by rheometric, mechanical, physicochemical, and morphological properties. From the analysis of transmission electron microscopy (TEM), dispersion in nanometric scale (below 100nm) of the cellulosic and mineral components throughout the elastomeric matrix was observed. XRD analysis suggested that fully exfoliated structure could be obtained by this method when low loading of silicate layers (up to 5 phr) is used. The results from mechanical tests showed that the nanocomposites presented better mechanical properties than SBR gum vulcanizate. Furthermore, 5 phr of clay is enough to achieve the best tensile properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of filler concentration on electrical conductivity andultralow-frequency dielectric properties

The effect of filler concentration on the dielectric properties in the ultralow-frequency region and on the electrical conductivity was studied for ethylene propylene rubber. First, we investigated the relation between the electrical conductivity and filler concentration: as the volume fraction of fillers q_a increased, the conductivity decreased in the low filler concentration region but increased abruptly in the high filler concentration region. The decrease and increase in conductivity can be explained with the action of carrier traps at the interface between EPR and fillers and with the formation of highly conductive paths of filler across the sample, respectively. Secondly, we studied the dielectric properties in the ultralow-frequency region which was obtained from the discharge current. As q_a increased, the relaxation time decreased in the low filler concentration region and then rose in the high filler concentration region. The polarization in the high filler concentration region can be explained by two-layer interfacial polarization between filler and rubber     

Structural Analysis of the Complex between Penta-EF-Hand ALG-2 Protein and Sec31A Peptide Reveals a Novel Target Recognition Mechanism of ALG-2

ALG-2, a 22-kDa penta-EF-hand protein, is involved in cell death, signal transduction, membrane trafficking, etc., by interacting with various proteins in mammalian cells in a Ca²⁺-dependent manner. Most known ALG-2-interacting proteins contain proline-rich regions in which either PPYPXnYP (type 1 motif) or PXPGF (type 2 motif) is commonly found. Previous X-ray crystal structural analysis of the complex between ALG-2 and an ALIX peptide revealed that the peptide binds to the two hydrophobic pockets. In the present study, we resolved the crystal structure of the complex between ALG-2 and a peptide of Sec31A (outer shell component of coat complex II, COPII; containing the type 2 motif) and found that the peptide binds to the third hydrophobic pocket (Pocket 3). While amino acid substitution of Phe⁸⁵, a Pocket 3 residue, with Ala abrogated the interaction with Sec31A, it did not affect the interaction with ALIX. On the other hand, amino acid substitution of Tyr¹⁸⁰, a Pocket 1 residue, with Ala caused loss of binding to ALIX, but maintained binding to Sec31A. We conclude that ALG-2 recognizes two types of motifs at different hydrophobic surfaces. Furthermore, based on the results of serial mutational analysis of the ALG-2-binding sites in Sec31A, the type 2 motif was newly defined.     

Anisotropic Thermal Expansion of β-Ca2SiO4 Monoclinic Crystal

Crystals of β-Ca₂SiO₄ (space group P 12₁/ n 1) were examined by high-temperature powder X-ray diffractometry to determine the change in unit-cell dimensions with temperature up to 645°C. The temperature dependence of the principal expansion coefficients (α_i) found from the matrix algebra analysis was as follows: α₁= 20.492 × 10⁻⁶+ 16.490 × 10⁻⁹ ( T - 25)°C⁻¹, α₂= 7.494 × 10⁻⁶+ 5.168 × 10⁻⁹( T - 25)°C⁻¹, α₃=−0.842 × 10⁻⁶− 1.497 × 10⁻⁹( T - 25)°C⁻¹. The expansion coefficient α₁, nearly along [302] was approximately 3 times α₂ along the b -axis. Very small contraction (α₃) occurred nearly along [     01]. The volume changes upon martensitic transformations of β↔α_L' were very small, and the strain accommodation would be almost complete. This is consistent with the thermoelasticity.     

Catalytic decomposition of N2O over supported rhodium catalysts: high activities of Rh/USY and Rh/Al2O3 and the effect of Rh precursors

The catalytic decomposition of nitrous oxide to nitrogen and oxygen has been studied over Al₂O₃-supported and zeolite-supported Rh catalysts. The activities of Rh/Al₂O₃ and Rh/USY (ultrastable Y zeolite) catalysts prepared from Rh(NO₃)₃ were higher than those of Rh/ZSM-5 and Rh/ZnO reported in the literature, while the activity of a Rh/Al₂O₃ catalyst prepared from RhCl₃ was suppressed severely in spite of the high H/Rh and CO/Rh values. The catalytic activity of N₂O decomposition was sensitive not only to the Rh dispersion but also to the preparation variables such as the Rh precursors and the supports used. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation of (0 2 0)-oriented BaTi2O5 thick films and their dielectric responses

Barium dititanate (BaTi₂O₅) thick films were prepared on a Pt-coated Si substrate by laser chemical vapor deposition, and ac electric responses of (0 2 0)-oriented BaTi₂O₅ films were investigated using several equivalent electric circuit models. BaTi₂O₅ films in a single phase were obtained at a Ti/Ba molar ratio (m_Ti/Ba) of 1.72–1.74 and deposition temperature (T_dep) of 908–1065 K as well as m_Ti/Ba = 1.95 and T_dep = 914–953 K. (0 2 0)-oriented BaTi₂O₅ films were obtained at m_Ti/Ba = 1.72–1.74 and T_dep = 989–1051 K. BaTi₂O₅ films had columnar grains, and the deposition rate reached 93 μm h^?1. The maximum relative permittivity of the (0 2 0)-oriented BaTi₂O₅ film prepared at T_dep = 989 K was 653 at 759 K. The model of an equivalent circuit involving a parallel combination of a resistor, a capacitor, and a constant phase element well fitted the frequency dependence of the interrelated ac electrical responses of the impedance, electric modulus, and admittance of (0 2 0)-oriented BaTi₂O₅ films.