Biomedical subjects

Keiichi Sato

Publications and source records attributed to Keiichi Sato.

7 recordsLinked to original sources

PubMed2005

Interspecific pairs of class II S haplotypes having different recognition specificities between Brassica oleracea and Brassica rapa.

There are several pairs of similar class I S haplotypes between Brassica oleracea and Brassica rapa. The similar S halotypes in these interspecific pairs have been reported to have the same recognition specificities. In the present study, three interspecific pairs showing a high sequence similarity were found in class II S haplotypes, i.e. between BoS-2b (B. oleracea S-2b) and BrS-44 (B. rapa S-44), between BoS-5 and BrS-40, and between BoS-15 and BrS-60. By pollination tests using interspecific hybrids between B. oleracea and B. rapa, BoS-5 and BoS-2b were revealed to have slightly and completely different recognition specificities from those of BrS-40 and BrS-44, respectively. The recognition reaction between SP11 and SRK of BoS-15 was suggested to be incomplete. The regions of class II SP11 and SRK important for self-recognition specificity and the diversification of class II S haplotypes are discussed herein.

Alleles↗

PubMed2005

Concentrations, enrichment and predominant sources of Sb and other trace elements in size classified airborne particulate matter collected in Tokyo from 1995 to 2004.

APM was collected and trace elements existing in the particles were monitored since May 1995 in this study. APM sample was collected separately by size (d < 2 microm, 2-11 microm and >11 microm) on the roof of the university building (45 m above ground) in the campus of Faculty of Science and Engineering, Chuo University, Tokyo, Japan, using an Anderson low volume air sampler. The collected sample was digested by HNO3, H2O2 and HF using a microwave oven, and major elements (Na, Mg, Al, K, Ca and Fe) were measured by ICP-AES, and trace elements (Li, Be, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba and Pb) were measured by ICP-MS. It was observed that the APM concentration was higher between the winter and the spring, compared to during the summer. The enrichment factor was calculated for each element in each set of APM (d < 2 microm, 2-11 microm and >11 microm). Seasonal trends of enrichment factors were examined, and the elements were classified into 3 groups according to the common seasonal behavior. It is likely that the elements in the same group have common origins. Toxic pollutant elements (Sb, Se, Cd, Pb and As) were found in small particles with d of <2 microm in concentrated levels. Antimony (Sb) had the highest enrichment factor, and the results suggested that Sb level in APM was extremely high. The origins of Sb were sought, and wastes from plastic incineration and brake pad wears of automobiles were suspected. Each set of APM (d < 2 microm, 2-11 microm and >11 microm) was classified by the shape, and the shape-dependent constituents of a single APM particle were quantitatively measured by SEM-EDX. High concentration of Sb was found in APM <2 microm and square particles. Particles less than 2 microm and square shaped particles were major particles produced by actual car braking experiments. From these experimental results it was concluded that the source of Sb in squared APM <2 microm is considered to be from brake pad wear.

Air Pollutants↗

PubMed2004

Context-sensitive approach for interactive systems design: modular scenario-based methods for context representation.

As information technology becomes more ubiquitous in our work and daily life environments, understanding contexts of activities becomes critical to enhance a foundation for human-centered design practice. This research introduces a conceptual framework for defining, representing and incorporating contexts as core information for interactive systems design. Modular Scenario Composition Method was developed as a mechanism for linking descriptive field study information and analytical aspect models representing many viewpoints involved in the system development and use processes. Design Information Framework (DIF) previously developed by the author was used as a common information platform to bridge different information representation formats including scenarios and aspect models. By combining modular scenarios and aspect models representing contexts, chains of relations between contexts, their triggering factors, and their influences on user actions can explicitly be described.

Humans↗

PubMed2004

[Home chemotherapy by concomitant UFT + Leucovorin (po.) in postoperative colorectal cancer patients assessed with Dukes D and curability C colorectal cancer].

UNLABELLED: Concomitant treatment with 5-fluorouracil (5-FU) and Leucovorin (LV) is positioned as the standard chemotherapy against colorectal cancer. We noted the action of LV to enhance the effect of biochemical modulation by 5-FU, and made an attempt at home chemotherapy with UFT + LV by oral administration, in consideration to the convenience of patients. SUBJECTS: The subjects of this study were 24 post-operative patients who had been assessed with Dukes D and curability C colorectal cancer with measurable metastatic lesions and who could tolerate chemotherapy. METHODS: 1 course of treatment consisted of 2 weeks of UFT at 300-400 mg/m2/day and LV at 15 mg/body/day followed by 2 weeks of drug withdrawal. The administration was conducted for 4 courses or more as the target. Unless serious adverse reaction occurred, dose increase of UFT was allowed. RESULTS: The efficacy rate in the 22 patients who were assessable was 22.7%. There were 11 NC patients, accounting for half (50%) of the subjects. This home chemotherapy is expected to become an alternative chemotherapy against colorectal cancer in the future, because the treatment does not require hospitalization and has less impact on the QOL of patients.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

Size-dependency of DL-lactide/glycolide copolymer particulates for intra-articular delivery system on phagocytosis in rat synovium.

PURPOSE: The present study evaluated the size-dependency of DL lactide/glycolide copolymer (PLGA) particulates for an intra articular delivery system on phagocytosis in the rat synovium after administering directly into the joint cavity. We also investigated the biocompatibility of PLGA particulate systems administered directly into the joint cavity of the rat. METHODS: Fluoresceinamine bound PLGA (FA-PLGA) nanospheres and microspheres were prepared by the modified emulsion solven diffusion method. The suspension of these particulate systems was administered into the rat-joint cavity and the biological action of the synovium was evaluated by histological inspection and fluorescence microscopy. RESULTS: A colloidal suspension of the FA-PLGA nanospheres, with a mean diameter of 265 nm, was phagocytosed in the synovium by the macrophages infiltrated through the synovial tissues. The phagocytosed nanospheres were delivered to the deep underlying tissues. An aqueous suspension of the FA-PLGA microspheres, with a mean diameter of 26.5 microm, was not phagocytosed in the macrophages. The macrophages slightly proliferated in the epithelial lining synovial-cells and the microspheres were covered with a granulation of multinucleated giant cells. The molecular weights of the polymer in these particulate systems were slowly reduced in the synovium. Localize inflammatory responses were almost undetected. CONCLUSIONS: PLGA nanospheres should be more suitable for delivery to inflamed synovial tissue than microspheres due to their ability to penetrate the synovium. PLGA particulate systems with biocompatibility in the joint can provide local-therapy action in joint disease in a different manner depending on the size of the system.

Animals↗

PubMed2002

Recognition specificity of self-incompatibility maintained after the divergence of Brassica oleracea and Brassica rapa.

The determinants of recognition specificity of self-incompatibility in Brassica are SRK in the stigma and SP11/SCR in the pollen, respectively. In the pair of S haplotypes BrS46 (S46 in B. rapa) and BoS7 (S7 in B. oleracea), which have highly similar SRK alleles, the SP11 alleles were found to be similar, with 96.1% identity in the deduced amino acid sequence. Two other pairs of S haplotypes, BrS47 and BoS12, and BrS8 and BoS32, having highly similar SRK and SP11 alleles between the two species were also found. The haplotypes in each pair are considered to have been derived from a single S haplotype in the ancestral species. The allotetraploid produced by interspecific hybridization between homozygotes of BrS46 and BoS15 showed incompatibility with a BoS7 homozygote and compatibility with other B. oleracea S haplotypes in reciprocal crossings. This result indicates that BrS46 and BoS7 have maintained the same recognition specificity after the divergence of the two species and that amino acid substitutions found in such cases in both SRK alleles and SP11 alleles do not alter the recognition specificity. DNA blot analysis of SRK, SP11, SLG and other S-locus genes showed different DNA fragment sizes between the interspecific pairs of S haplotypes. A much lower level of sequence similarity was observed outside the genes of SRK and SP11 between BrS46 and BoS7. These results suggest that the DNA sequences of the regions intervening between the S-locus genes were diversified after or at the time of speciation. This is the first report demonstrating the presence of common S haplotypes in different plant species and presenting definite evidence of the trans-specific evolution of self-incompatibility genes.

Amino Acid Sequence↗

PubMed2002

Coevolution of the S-locus genes SRK, SLG and SP11/SCR in Brassica oleracea and B. rapa.

Brassica self-incompatibility (SI) is controlled by SLG and SRK expressed in the stigma and by SP11/SCR expressed in the anther. We determined the sequences of the S domains of 36 SRK alleles, 13 SLG alleles, and 14 SP11 alleles from Brassica oleracea and B. rapa. We found three S haplotypes lacking SLG genes in B. rapa, confirming that SLG is not essential for the SI recognition system. Together with reported sequences, the nucleotide diversities per synonymous and nonsynonymous site (pi(S) and pi(N)) at the SRK, SLG, and SP11 loci within B. oleracea were computed. The ratios of pi(N):pi(S) for SP11 and the hypervariable region of SRK were significantly >1, suggesting operation of diversifying selection to maintain the diversity of these regions. In the phylogenetic trees of 12 SP11 sequences and their linked SRK alleles, the tree topology was not significantly different between SP11 and SRK, suggesting a tight linkage of male and female SI determinants during the evolutionary course of these haplotypes. Genetic exchanges between SLG and SRK seem to be frequent; three such recent exchanges were detected. The evolution of S haplotypes and the effect of gene conversion on self-incompatibility are discussed.

Amino Acid Sequence↗