Biomedical subjects

C Honda

Publications and source records attributed to C Honda.

At least 19 recordsLinked to original sources

PubMed2006

Detailed images of asteroid 25143 Itokawa from Hayabusa.

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Journal Article↗

PubMed2003

Structure and expression of spermidine synthase genes in apple: two cDNAs are spatially and developmentally regulated through alternative splicing.

Three cDNAs (MdSPDS1, 2a and 2b) encoding spermidine synthase (SPDS), a key enzyme in the polyamine biosynthesis, have been cloned from apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. The deduced amino acid sequences of their protein products share 76-83% identity with SPDSs of other higher plants. A comparison of the sequences of the three cDNAs and of the two corresponding genomic DNA fragments (SPDS1 and SPDS2) indicated that MdSPDS1 was transcribed from the SPDS1 sequence, whereas MdSPDS2a and MdSPDS2b were both derived from SPDS2 by alternative splicing. To learn more about the physiological roles of MdSPDS1, MdSPDS2a and MdSPDS2b, Northern analyses were carried out, together with measurements of polyamine content. Levels of both MdSPDS1 and MdSPD2a were higher in young leaves than in mature leaves and shoots. In fruits, mRNA levels were nearly as high as in young leaves and remained high during fruit development. By RT-PCR, MdSPDS2b transcripts were detected in mature leaves and shoots, but not in young leaves and fruits. These results indicate that MdSPDS2a and MdSPDS2b are differentially regulated in a tissue- and developmentally specific manner. The content of free polyamines in mesocarp tissues was measured at five stages of fruit development. At all stages, spermidine (Spd) was the predominant form of polyamine. The level of Spd was high at the early growth stage and declined to about 90% during later developmental stages. The possible regulation of SPDS expression during apple fruit development is discussed.

Alternative Splicing↗

PubMed2002

Myb-related genes of the Kyoho grape ( Vitis labruscana) regulate anthocyanin biosynthesis.

Partial cDNAs of myb-related regulatory genes were isolated from the tetraploid Kyoho grape ( Vitis labruscana: V. labrusca x V. vinifera) and the expression patterns of the corresponding genes were studied. Since MybA gene expression is closely related to coloring and/or ripening of the berry (expression increases strongly with the commencement of coloring and berry softening, and is detected only in berry skin and flesh), full-length cDNAs for the gene were isolated from a mature-berry cDNA library. Three different species of MybA were identified from the cDNA sequences. Delivery of these cDNAs to somatic embryos of grape led to the induction of reddish-purple spots and UDP-glucose:flavonoid 3- O-glucosyltransferase (UFGT) gene expression in non-colored embryos. The UFGT transcript was not detected in control embryos, while other structural genes for anthocyanin biosynthesis were expressed in both control and pigmented embryos. In addition, introduction of the UFGT gene induced the same reddish-purple spots in embryos. In contrast, treatment with the leucoanthocyanidin dioxygenase (LDOX) gene failed to induce these spots. Our results strongly suggest that MybA genes are involved in the regulation of anthocyanin biosynthesis in the grape via expression of the UFGT gene.

Amino Acid Sequence↗

PubMed2001

Isolation and expression analysis of gibberellin 20-oxidase homologous gene in apple.

To characterize the gibberellin (GA) 20-oxidase gene in apple, the genomic and cDNA clone from "Fuji" apple (accession no. AB037114) was isolated. The deduced amino acid sequence of this cDNA showed 71% and 66% identity to those of GA 20-oxidase cloned from French bean and Arabidopsis, respectively. The transcript of this gene was detected mainly in immature seeds between 1-3 months after full bloom. These results suggested that this apple GA 20-oxidase gene might be involved in GA biosynthesis in developing apple seed.

Amino Acid Sequence↗

PubMed2000

Skin reactions after breast-conserving therapy and prediction of late complications using physiological functions.

BACKGROUND: The temperature of the skin remains elevated long after breast-conserving treatment with irradiation, perhaps because evaporative cooling is impaired. We investigated physiological changes of the irradiated skin and reevaluated the radiosensitivity of sweat glands on a functional basis to determine whether severe complications can be predicted. METHODS: Breast and axillary skin temperatures were measured with thermography and sweat production in response to local thermal stimuli was measured on the basis of changes in electrical skin resistance with a bridge circuit in 45 women before, during, and after breast irradiation for breast cancer. RESULTS: Breast and axillary skin temperatures were significantly increased after irradiation. In response to cutaneous thermal stimuli, the electric skin resistance of nonirradiated areas decreased significantly because of sweating, but that of irradiated areas was unchanged. CONCLUSION: Impairment of sweating may play an important role in skin damage after irradiation. Although glandular tissue is not usually radiosensitive, the results of our functional assessment suggest that sweat glands are more radiosensitive than expected.

Adult↗

PubMed2000

Phenanthrenes from Dendrobium plicatile.

From Dendrobium plicatile stems, three phenanthrenes were isolated. The structures are 2,5-dihydroxy-4,9,10-trimethoxyphenanthrene, 2,5-dihydroxy-4-methoxyphenanthrene and 2,5,9-trihydroxy-4-methoxy-9,10-dihydrophenanthrene.

Magnetic Resonance Spectroscopy↗

PubMed2000

The evolution of C4 plants: acquisition of cis-regulatory sequences in the promoter of C4-type pyruvate, orthophosphate dikinase gene.

In a previous study, we identified the C4-like pyruvate, orthophosphate dikinase gene (Pdk) in the C3 plant rice, with a similar structure to the C4-type Pdk in the C4 plant maize. In order to elucidate the differences between C4-type and C4-like Pdk genes in C4 and C3 plants, we have produced chimeric constructs with the beta-glucuronidase (GUS) reporter gene under the control of the Pdk promoters. In transgenic rice, both rice and maize promoters directed GUS expression in photosynthetic organs in a light-dependent manner. However, the maize promoter exhibited a much higher transcriptional activity than the rice promoter did. These results indicate that the rice C4-like Pdk gene resembles the maize C4-type Pdk gene in terms of regulation of expression. We also tested the activity of the rice promoter in transgenic maize. GUS activity was seen in both photosynthetic and non-photosynthetic organs. Thus, the rice promoter does not confer a strict organ-specific gene expression, as the maize promoter does. Moreover, the rice promoter directed GUS expression not only in mesophyll cells but also in bundle sheath cells, whereas the maize promoter directed expression only in mesophyll cells. Taken together, the results obtained from both transgenic maize and rice demonstrate that the rice and maize promoters differ not only quantitatively, but also qualitatively, in terms of their cell- and organ-specificity. Experiments with swapped promoters using the rice and maize promoters further demonstrated that a limited sequence region from -330 to -76 of the maize promoter confers light-regulated, high-level expression to the rice promoter in maize mesophyll protoplasts. We conclude the gain of cis-acting elements conferring high-level expression and mesophyll cell specificity was necessary for establishment of a C4-type Pdk gene during the course of evolution from C3 to C4 plants.

Evolution, Molecular↗

PubMed2000

Chemical states and lattice dynamics of alpha-diimine Fe2+ complexes intercalated into gamma-zirconium phosphate.

The alpha-diimine Fe2+ complexes, [Fe(phen)3]2+, [Fe(bpy)3]2+, and [Fe(terpy)2]2+, (phen: 1,10-phenanthroline, bpy: 2,2'-bipyridyl, terpy: alpha,alpha',alpha''-tripyridine) were intercalated into zirconium dihydrogenphosphate phosphate dihydrate (gamma-zirconium phosphate, gamma-ZrP), Zr(PO4)(H2PO4).2H2O. The rate of the intercalation, the molar ratio of Fe to Zr, was found to be 3.82-7.76%. Mössbauer spectra indicated that one part of [Fe(phen)3]2+ and [Fe(bpy)3]2+ changed from a low-spin Fe2+ to high-spin Fe2+ state on intercalation, but [Fe(terpy)2]2+ did not change in chemical state. The lattice dynamics of the complexes and the intercalation compounds were investigated in terms of the temperature dependence of the area intensity on the Mössbauer spectra. A linear relationship was established for all the complex salts and the intercalation compounds investigated between the ln[A(T)/A(82)] and absolute temperature, T, where A(T) and A(82) show the intensities of a doublet at T and 82 K of the Mössbauer spectra, respectively. From the slope of the linear relation, the theta2M values, which were derived based on the Debye approximation of lattice vibration, were evaluated for the complex salts and the intercalation compounds. The Fe2+ complexes showed theta2M values of 1.27 to 2.32 x 10(6), whereas the intercalation compounds showed very similar values to each other, ranging from 2.19 to 2.39 x 10(6), irrespective of different alpha-diimine ligands. The results were explained in terms of the characteristic layered structure of zirconium phosphate, and by the tight bond between the alpha-diimine Fe2+ complexes and the host gamma-ZrP.

Algorithms↗

PubMed2000

Studies on thermal aggregation of bovine serum albumin as a drug carrier.

The irreversible thermal aggregation rate and process of bovine serum albumin (BSA) were investigated by means of light scattering technique as a function of temperature. The increasing rate of particle radius was affected by the aggregation temperature, concentration and the presence of fatty acid. The particle radius was larger and the aggregation rate was faster for fatty acid free BSA at higher temperature and concentration. Two thermal aggregation processes were observed at relatively low temperature and concentration, both for fatty acid containing (C-BSA) and fatty acid free BSA (F-BSA). The first process proceeds by an inter-monomer aggregation mechanism, and the second process by inter-aggregates aggregation. The first process is represented by a power law as Rhapp proportional to t(z), which is diffusion limited cluster aggregation (DLCA).

Fatty Acids↗

PubMed2000

[Giant osteoma of the temporal bone with otitis media: a case study].

A 71-year-old female presented with a giant osteoma of the right temporal bone and otitis media. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of the giant osteoma. An operation was performed to alleviate the difficult-to-treat otitis media and to address the related cosmetic problem. During the operation, three-dimensional CT (3D-CT) was very helpful in understanding the relationship between the tumor and the peripheral structures. Removal of the tumor improved the patient's otitis media. Osteoma of the temporal bone is rare. Only twenty-one cases of mastoid osteoma have been reported in Japan. In the present study, we review osteomas of the temporal bone and discuss their management.

Aged↗

PubMed1999

Pharmacokinetics of 10B-p-boronophenylalanine in tumours, skin and blood of melanoma patients: a study of boron neutron capture therapy for malignant melanoma.

To optimize the neutron dose for boron neutron capture therapy (BNCT), the boron-10 (10B) concentration kinetics of 10B-p-boronophenylalanine (BPA) were analysed in 22 melanoma patients with primary or metastatic melanomas who received BPA and subsequently underwent BNCT or surgery. The blood concentration in nine patients receiving 179.7+/-14.9 mg/kg BPA increased with time during intravenous infusion, peaked at the end of administration and decreased thereafter. The peak values at the end of administration were 9.4 2.6 microg 10B/g blood, and half-lives for the initial and second components of the blood clearance were 2.8 and 9.2 h, respectively. Skin concentrations in the 10 patients varied from case to case; however, skin-to-blood ratios were relatively constant at 1.31+/-0.22 during the 6 h after the end of administration. Boron concentrations in the tumours resected from the seven patients who were operated on decreased in parallel to the blood values, the tumour-to-blood ratio being relatively constant at 3.40+/-0.83. The present analytical data of BPA pharmacokinetics support our previous approach for optimizing the timing of irradiation and setting the neutron flux large enough for tumour eradication but still tolerable for normal skin.

Adult↗

PubMed1999

[A case of an intracranial tuberculoma, mimicking meningioma, that developed during treatment with anti-tuberculous agents].

A 54-year old female patient presented with intracranial tuberculoma attached to the dura mater during treatment with anti-tuberculous agents. Compared tomography (CT) and magnetic resonance imaging (MRI) revealed a lesion resembling a cystic meningioma. A granulomatous tumor that adhered to the cerebral cortex and dura was totally removed. Histological diagnosis was epithelioid granuloma. After removal of the tuberculoma and treatment with anti-tuberculous medications, the patient seemed to be cured, and regrowth of the tumor has not been observed to date. Tuberculoma mimicking meningioma is a very rare phenomenon. In the present study, we review intracranial tuberculomas and discuss their radiological features.

Antitubercular Agents↗

PubMed1998

Decreased GA1 content caused by the overexpression of OSH1 is accompanied by suppression of GA 20-oxidase gene expression.

We previously reported that overexpression of the rice homeobox gene OSH1 led to altered morphology and hormone levels in transgenic tobacco (Nicotiana tabacum L.) plants. Among the hormones whose levels were changed, GA1 was dramatically reduced. Here we report the results of our analysis on the regulatory mechanism(s) of OSH1 on GA metabolism. GA53 and GA20, precursors of GA1, were applied separately to transgenic tobacco plants exhibiting severely changed morphology due to overexpression of OSH1. Only treatment with the end product of GA 20-oxidase, GA20, resulted in a striking promotion of stem elongation in transgenic tobacco plants. The internal GA1 and GA20 contents in OSH1-transformed tobacco were dramatically reduced compared with those of wild-type plants, whereas the level of GA19, a mid-product of GA 20-oxidase, was 25% of the wild-type level. We have isolated a cDNA encoding a putative tobacco GA 20-oxidase, which is mainly expressed in vegetative stem tissue. RNA-blot analysis revealed that GA 20-oxidase gene expression was suppressed in stem tissue of OSH1-transformed tobacco plants. Based on these results, we conclude that overexpression of OSH1 causes a reduction of the level of GA1 by suppressing GA 20-oxidase expression.

Amino Acid Sequence↗

PubMed1998

Cloning of rabbit TR4 and its bone cell-specific activity to suppress estrogen receptor-mediated transactivation.

To clone a new nuclear receptor, we screened a rabbit heart complementary DNA (cDNA) library with degenerate oligonucleotide probes corresponding to the DNA-binding domain of nuclear receptors, which is highly conserved among receptors. One of the cDNA clones, clone 23, encodes a novel protein of 596 amino acids, and predicted molecular mass is 66 kDa. Homology search analysis identified this protein as rabbit TR4 (TR4-0). We also cloned the cDNA encoding a rabbit TR4 isoform (TR4-1), which lacks the putative C-terminal ligand-binding domain (350 amino acids) caused by a 23-bp exon deletion, which probably occurred during messenger RNA (mRNA) splicing. Northern blot analysis showed that TR4s are expressed with two kinds of mRNAs (9.0 kb and 2.8 kb), both of which are relatively abundant in brain, testis, and bone. RT-PCR analysis, using pairs of primers specific for each TR4, showed that both types of receptor express in various tissues. Furthermore, both are present in primary osteoblasts and bone marrow cells, though the mRNA levels of TR4-0 were much higher than those of TR4-1. A functional study, using a transient transfection assay, showed that both receptors suppressed retinoid X receptor (RXR)-retinoid acid receptor, RXR-TR, and RXR-VDR-mediated transactivation significantly in COS-1 and osteosarcoma cells (UMR-106, ROS17/2.8) and that TR4-0 was much more effective than TR4-1. Unexpectedly, we found that the TR4s effectively suppressed estrogen receptor-mediated transactivation in bone cells, but neither in kidney (COS-1) nor breast cancer cells (MCF-7, one of the major target cells of the estrogen action). Thus, the present study shows a novel property of the TR4 orphan receptor, acting as a bone cell-specific repressor in the estrogen receptor-mediated signaling pathway.

Amino Acid Sequence↗

PubMed1997

In vivo diagnosis of human malignant melanoma with positron emission tomography using specific melanoma-seeking 18F-DOPA analogue.

Detection and diagnosis of human malignant melanoma by Positron Emission Tomography (PET) using 18F-10B-L-BPA, a specific melanogenesis-seeking compound synthesized for use in Boron Neutron Capture Therapy for malignant melanoma (NCT), has been developed. This resulted in a novel, highly effective methodology for the selective three dimensional imaging of metastatic malignant melanomas, and for accurate determination of 10B concentration in the tumor and surrounding tissue, providing almost all diagnostic information necessary for complete non-invasive radiation dose planning in the treatment of malignant melanoma both for NCT as well as other therapeutic modalities.

Boron↗

PubMed1996

Biosynthesis of the acetylenic compounds in cultured cells of Asparagus officinalis from D- and 13C-labelled phenylalanines.

Studies on the biosynthetic pathway of acetylenic compounds, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and its related compounds, in cultured cells of Asparagus officinalis L. (Liliaceae) revealed that all of the 17 carbon atoms in their skeletons are supplied by phenylalanine. It is also concluded that p-substituted phenylacetylenic moieties (the C6-C2 unit) in these compounds are derived from C6-C3 shikimate pathway metabolites via phenylalanine. As a working hypothesis concerning the C6-O-C3 unit formation, a spirotetrahydrofuran type intermediate is predicted.

Acetylene↗

PubMed1995

Thioredoxin h is one of the major proteins in rice phloem sap.

Sieve tubes play important roles in the transfer of nutrients as well as signals. Hundreds of proteins were found in pure phloem sap collected from rice (Oryza sativa L. cv. Kantou) plants through the cut ends of insect stylets. These proteins may be involved in nutrient transfer and signal transduction. To characterize the nature of these proteins, the partial amino-acid sequence of a 13-kDa protein, named RPP13-1, that was abundant in the pure phleom sap was determined. A cDNA clone of 687 bp, containing an open reading frame of 122 amino acids, was isolated using corresponding oligonucleotides as a probe. The deduced amino-acid sequence was very similar to that of the ubiquitous thiol redox protein, thioredoxin. The consensus sequences of thioredoxins are highly conserved. No putative signal peptide was identified. Antiserum against wheat thioredoxin h cross-reacted with RPP13-1 in the phloem sap of rice plants. RPP13-1 produced in Escherichia coli was reactive to antiserum against wheat thioredoxin h. Both E. coli-produced RPP13-1 and the phloem sap proteins catalyzed the reduction of the disulfide bonds of insulin in the presence of dithiothreitol. These results indicate that an active thioredoxin is a major protein translocating in rice sieve tubes.

Amino Acid Sequence↗

PubMed1995

Biosynthesis of acetylenic compounds in cultured cells of Asparagus officinalis from [1-13C]- and [U-13C] Glucose.

The biosynthetic pathway of phenolics with an acetylenic group, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol (1) and its related compounds, isolated from suspension-cultured cells of Asparagus officinalis L. (Liliaceae), was studied in feeding experiments using [1-13C]- and [U-13C] glucose. Analyses of the 13C-NMR spectra of the methyl ether and acetate of the 13C-labelled species of 1 indicated that the aromatic rings at both ends of the molecule are formed from shikimic acid. It was also assumed that the acetylenic carbons in the C5 chain could be incorporated together with its adjacent aromatic ring through any phenethyl class compound derived from phenylpropanoids, and the propenylene carbon through glycolysis metabolites with C3 carbon units.

Acetylation↗