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  • Author: M. Hirata x
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Abstract

We summarize historical perspective of the transuranium elements, neptunium (Np) through lawrencium (Lr), and recent progress on production, and nuclear and chemical properties of these elements. Exotic decay properties of heavy nuclei are also introduced. Chemical properties of transuranium elements in aqueous and solid states are summarized based on the actinide concept.

The transactinide nuclides 261Rf and 262Db have been successfully produced in the 248Cm(18O,5n) reaction at 99 MeV and in the 248Cm(19F,5n) reaction at 100, 103, and 106 MeV, respectively, at the JAERI tandem accelerator. The on-line ion exchange experiments with an automated fast and repetitive liquid chromatography separation system were performed in the HNO3/HF system using Rf homologues 89mZr and 167,165Hf produced in the 89Y(p,n) and 152Gd(18O,xn) reactions, respectively. The radiotracers 88Zr, 175Hf, and 234Th were also prepared and the distribution coefficients on ion exchange resins were measured systematically in 1-11 M HCl and 1-14 M HNO3 with the batch method. It was found that anion exchange experiments of Rf in 8 M HNO3 and 9 M HCl provided information useful to extract the ionic radius of Rf and to verify the influence of relativistic effects.

Phytochemical investigation of Cassia petersiana Bolle leaves afforded four new compounds, including two chromone derivatives, 7-acetonyl-5-hydroxy-2-methylchromone (petersinone 1, 1) and 7-(propan-2ʹ-ol-1ʹ-yl)-5-hydroxy-2-methylchromone (petersinone 2, 2), two benzoic acid derivatives, 5-methyl-3-(propan-2ʹ-on-1ʹ-yl) benzoic acid (petersinone 3, 3) and 5-(methoxymethyl)-3-(propan-2ʹ-ol-1ʹ-yl) benzoic acid (petersinone 4, 4), and glyceryl- 1-tetracosanoate (6), in addition to the known compound sistosterol-3-β-ᴅ-glycoside (5). The structures of these compounds were determined by comprehensive NMR studies, including DEPT, COSY, HMQC, HMBC, MS and IR.

Compounds 1, 2, 5 and 6 were tested for antioxidant, anti-cancer and immunostimulatory properties. The biological investigations indicated that compound 6, among others, possessed the highest anti-cancer activity against hepatocellular carcinoma, immunoproliferative activity via induction of T-lymphocytes and macrophage proliferation, anti-inflammatory activity as indicated by NO inhibition, and antioxidant activity against DPPH radicals. Moreover, compound 5 was the most effective cytotoxic compound against breast carcinoma and stimulated a consistent immunoproliferative effect on lymphocytes and macrophages combined with strong NO inhibitory activity, while compound 1 was promising as immunoproliferative agent and may act as anti-inflammatory agent as a consequence of its NO inhibitory activity.

Abstract

Background: Pioglitazone is a peroxisome proliferator-activated receptor gamma (PPARγ) activator used in the treatment of type 2 diabetes (DM2) patients and it has been suggested that can induce bone loss. Tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) mRNA expression in blood leukocytes and the relationship with polymorphisms and bone markers in DM2 treated with pioglitazone were investigated.

Methods: DM2 (n=53) and normoglycemic (NG, n=52) individuals were included. DM2 patients were treated with pioglitazone (45 mg/day/16 weeks). mRNA expression was evaluated by real-time polymerase chain reaction (PCR). TNFA -308G>A and IL6 -174G>C polymorphisms were detected by PCR-RFLP and high resolution melting polymerase chain reaction (HRM-PCR).

Results: Pioglitazone reduced bone specific alkaline phosphatase (bALP) and increased TNFα in DM2 group (p<0.001). DM2 or pioglitazone did not influence TNFα and IL-6 expression (p>0.05). TNFA -308A allele was associated with reduced basal TNFα mRNA levels in NG and DM2 and reduced alkaline phosphatase (tALP) after treatment (p<0.05). IL6 -174C allele was associated with decreased oral glucose tolerance test (OGTT)-2 h in DM2 individuals (p<0.05).

Conclusions: TNFA -308G >A polymorphism appear to be involved in regulation of gene expression independently of hyperglycemia and its interaction with pioglitazone may modify tALP, a important bone marker. IL6 -174G>C variant is related with reduced risk of postprandial hyperglycemia but not with mRNA expression or bone markers.

Summary

Chemical studies on element 104, rutherfordium (Rf), at JAERI (Japan Atomic Energy Research Institute) are reviewed. The transactinide nuclide 261Rf has been produced in the reaction 248Cm(18O, 5n) at the JAERI tandem accelerator with the production cross section of about 13 nb. On-line anion-exchange experiments on Rf together with the lighter homologues, group-4 elements Zr and Hf, in acidic solutions have been conducted with a rapid ion-exchange separation apparatus. From the systematic study of the anion-exchange behavior of Rf, it has been found that the properties of Rf in HCl and HNO3 solutions are quite similar to those of Zr and Hf, definitely confirming that Rf is a member of the group-4 elements. However, we have observed an unexpected chemical behavior of Rf in HF solutions; the fluoride complex formation of Rf is significantly different from those of the homologues. Prospects of extending chemical studies on transactinide elements in the near future at JAERI are briefly considered.

Abstract

A method to grow homogeneous micro-sized diamond clusters on silicon by Hot-Filament Chemical Vapor Deposition in a homemade reactor is reported in this work. Thermal decomposition of a CH4:H2 mixture gases was carried out in a horizontal quartz-tube reactor at 2200 °C filament temperature and 1000 °C substrate temperature at relative low pressure around 150 Torr depositing diamonds on silicon wafers. The diamond micro-structures are formed by nano-crystalline diamonds, they have a rounded shape and a narrow particle size distribution around a micrometer. The diamond micro-structures synthesized in this work showed a strong Raman shift signal, a peak at 1330 cm‒1 typical of the diamond and a single optical trap was localized nearby 300 °C by Thermoluminescence analysis indicating that these diamond micro-structures could be a good thermoluminescent dosimeter material. Due to their excellent properties, diamonds obtained by this technique should find application in the biomedical and optoelectronic industry.

Abstract

Cathepsin V is a lysosomal cysteine peptidase highly expressed in corneal epithelium; however, its function in the eye is still unknown. Here, we describe the capability of cathepsin V to hydrolyze plasminogen, which is also expressed in human cornea at levels high enough to produce physiologically relevant amounts of angiostatin-related molecules. The co-localization of these two proteins suggests an important role for the enzyme in the maintenance of corneal avascularity, essential for optimal visual performance. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of plasminogen digestion by cathepsin V revealed the generation of three major products of 60, 50 and 40 kDa, which were electrotransferred to polyvinylidene difluoride membranes and excised for characterization. NH2-terminal amino acid sequencing of these fragments revealed the sequences EKKVYL, TEQLAP and LLPNVE, respectively. These data are compatible with cleavage sites at plasminogen F94–E95, S358–T359 and V468–L469 peptide bonds generating fragments of the five-kringle domains. In contrast, we did not detect any plasminogen degradation by cathepsins B, K and L. Using a Matrigel assay, we confirmed the angiogenesis inhibition activity on endothelial cells caused by plasminogen processing by cathepsin V. Our results suggest a novel physiological role for cathepsin V related to the control of neovascularization in cornea.

Abstract

Plasminogen is a glycoprotein implicated in angiogenesis and fibrin clot degradation associated with the release of angiostatin and plasmin activation, respectively. We have recently reported that cathepsin V, but not cathepsins L, B, and K, can release angiostatin-like fragments from plasminogen. Here, we extended the investigation to cathepsin S which has been implicated in angiogenesis and tumor cell proliferation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of plasminogen hydrolysis by cathepsin S revealed generation of two fragments (60 and 38 kDa). Amino-terminal sequencing indicated that cleavage occurs at the Leu469-Leu470 peptide bond. In contrast to cathepsin V, which possesses antiangiogenic activity, cathepsin S plasminogen cleavage products were not capable of inhibiting angiogenesis on endothelial cells. Moreover, we explored the different selectivities presented by cathepsins V and S towards plasminogen and synthesized fluorescence resonance energy transfer peptides encompassing the hydrolyzed peptide bonds by both enzymes. The peptide Abz-VLFEKKQ-EDDnp (Abz=ortho-aminobenzoic acid; EDDnp= N-[2,4-dinitrophenyl]ethylenediamine), hydrolyzed by cath-epsin V at the Phe-Glu bond, is a selective substrate for the enzyme when compared with cathepsins B, L, and S, whereas Abz-VLFEKKVYLQ-EDDnp is an efficient cathepsin L inhibitor. The demonstrated importance of the S3′-P3′ interaction indicates the significance of the extended subsites for enzyme specificity and affinity.