Biomedical subjects

Y Higuchi

Publications and source records attributed to Y Higuchi.

At least 145 records · Page 8Linked to original sources

PubMed1996

High-resolution crystal structures of two polymorphs of cytochrome c' from the purple phototrophic bacterium rhodobacter capsulatus.

The structures of two polymorphs of cytochrome c' from Rhodobacter capsulatus (RCCP) strain M110 have been determined by the molecular replacement method. Iron anomalous scattering data were used to confirm the molecular replacement solution. The structures were refined at 1.72 angstrom and 2.0 angstrom resolution to R-values of 15.0% and 16.3%, respectively. The RCCP molecule is a dimer and each of the identical 129 residue subunits folds as a four-helical bundle with a covalently bound heme group in the center. This structural motif resembles that of cytochromes c' reported from Rhodospirillum molischianum (RMCP), Rhodospirillum rubrum (RRCP), Chromatium vinosum (CVCP), Achromobacter xyloseoxidans (AXCP) and Alcaligenes denitrificans (ADCP). However, the architecture of the RCCP dimer, that is, the mode of association of subunits, differs substantially from that of the other cytochromes c'. In the RCCP dimer, the subunits are roughly parallel with each other and only helix B of each subunit participates in formation of the dimer interface. Measurement of the solvent-accessible surface area indicates that the dimer interface is smaller in RCCP than in the other cytochromes c'. In RMCP, CVCP, RRCP, AXCP and ADCP the subunits cross each other to form an X shape, and two helices, A and B, of each subunit interact across the dimer interface. These results are consistent with hydrodynamic measurements, which show that there is an equilibrium between monomers and dimer in RCCP, whereas the dimer is the predominant form in the other cytochromes c' for which structures have been determined. Structural comparison of the six cytochromes c' reveal that they can be divided into two groups. In group 1 cytochromes c', CVCP and RCCP, the amino acid sequences and the folding of subunits are arranged in such a way as to allow the formation of a deep channel between helices B and C with direct solvent accessibility to the heme sixth ligand position. There is no such channel in group 2 cytochromes c', RMCP, RRCP, AXCP and ADCP. This may account, in part, for the differences in carbon monoxide binding.

Amino Acid Sequence↗

PubMed1996

Crystallization and preliminary X-ray study of a new crystal form of cytochrome c' from Rhodobacter capsulatus.

A new crystal form of diheme cytochrome c' from Rhodobacter capsulatus has been obtained and preliminary crystallographic experiments have been performed. The crystals belong to the space group P2(1)2(1)2 with unit-cell dimensions of a = 47.82, b = 72.59, c = 34.32 A. The assumption that an asymmetric unit of the crystal contains one half of the homodimer molecule indicates that the monomers in the dimeric molecule may be related by a crystallographic twofold axis. Crystals diffract up to 1.7 A resolution using the X-ray beam from synchrotron radiation, and 11 127 unique structure factors were obtained with an R(merge) of 7.1% from 52 922 indexed reflections. Structure analysis by means of molecular-replacement methods is now underway.

Journal Article↗

PubMed1996

Congenital bilateral perisylvian syndrome: first report in a Japanese patient.

A Japanese boy with congenital bilateral perisylvian syndrome is described. He had oropharyngoglossal dysfunction and severe dysarthria. Magnetic resonance imaging of the brain disclosed bilateral perisylvian malformations suggesting polymicrogyria. The patient also showed mental retardation, epilepsy, and poor motor skills.

Adult↗

PubMed1996

Overexpression of p53 protein and histologic grades of dysplasia in colorectal adenomas.

PURPOSE: To clarify the relation between tumor-suppressor gene p53 expression and histologic grades of dysplasia in colorectal adenomas, we performed immunohistochemical analysis in a series of 59 colorectal polyps and 40 advanced carcinomas. METHODS: Adenomatous polyps were stained by hematoxylin and eosin and classified into mild, moderate, and severe dysplasia (intramucosal carcinoma), according to the World Health Organization's classification. RESULTS: p53 was positive in 7.1 percent (2/28) of mild, 29.4 percent (5/17) of moderate, and 62.5 percent (5/8) of severe dysplasia. In submucosal and advanced carcinomas, positivity rates were 75 percent (3/4) and 47.5 percent (19/40), respectively. Different staining patterns were found, according to grades of dysplasia. In the adenomas with mild or moderate dysplasia, a few focal crypts showed localized p53-positive staining. Adenomas with severe dysplasia had two different staining types. One was a focal staining type as shown in mild or moderate dysplasia; the other was a diffuse staining type, in which glands with mild or moderate dysplasia, surrounding severe dysplasia area, were also stained. Submucosal and advanced carcinomas showed a strong positive staining in cancer cells only. CONCLUSIONS: Overexpression of p53 protein in adenomas with mild or moderate dysplasia and existence of two types of expression in adenomas with severe dysplasia were observed. These facts suggested the possible existence of different pathways in the adenoma to carcinoma progression.

Adenoma↗

PubMed1996

Histologic investigation of hollow implants retrieved for psychological reasons.

OBJECTIVE: The purpose of this study was to radiologically, histologically, and histometrically evaluate bone in the hollow portion of three implants retrieved for psychological reasons. STUDY DESIGN: Three hollow implants retrieved from two patients were studied. We investigated the radiologic and histologic changes of these implants with the use of radiographs, light microscopy, image processing, and fluorescent microscopy. RESULTS: There were no radiologic and histologic degeneration around the implants. Histometric analysis of the hollow indicated that the average percentage of bone contact rate was 33.5% in case 1, 74.5% in case 2, and 18.4% in case 3; the average percentage of bone filling was 25.1%, 33.9%, and 6.6%, respectively. There was a great variation among the three cases in bone to implant contact and bone filling. CONCLUSION: The hollow portion in case 1 that penetrated into the maxillary sinus was encapsulated with fibrous tissue. The amount of bone tissue in the hollow portion seems to depend on the initial bone quality of the recipient sites.

Adaptation, Psychological↗

PubMed1996

Concerted movement of side chains in the haem vicinity observed on ligand binding in cytochrome c' from rhodobacter capsulatus.

We have determined the structure of n-butylisocyanide-bound Rhodobacter capsulatus cytochrome c'. This is the first example of a ligand-bound structure of a class IIa cytochrome c. Compared with the structure of native cytochrome c', there are significant conformational changes of amino acid residues in the haem vicinity, accompanied by a rearrangement of the hydrogen bonding pattern. The results suggest that rearrangements resulting from ligand binding could drive dimer dissociation in some species and also that the haem propionate may participate in proton transfer.

Amino Acid Sequence↗

PubMed1996

Antitumor effect of Streptococcus pyogenes by inducing hydrogen peroxide production.

The Su strain of Streptococcus pyogenes (S-coccus)-derived anticancer preparation, OK-432, which is immobilized by heating in the presence of penicillin G, is well known to have an immunopotentiating activity through activation of natural killer cells in vivo. In this study, a streptococcal anticancer preparation stronger than OK-432 was prepared. Live streptococci (S-cocci) of the Su strain were induced to acquire H202-producing ability by treatment with serum under aerobic conditions. The resulting preparation no longer possessed hemolytic activity, and was not viable. The serum-treated S-coccus preparation activated natural killer cells as well as OK-432 did, and had stronger antitumor activity than OK-432 did. These results suggest that the serum-treated S-coccus preparation would be a useful tool for chemotherapy, in addition to immunotherapy, for the treatment of cancer.

Adjuvants, Immunologic↗

PubMed1996

Age changes in the rat temporomandibular joint articular disc: a biochemical study on glycosaminoglycan content.

The temporomandibular joint (TMJ) articular discs were removed from female Sprague-Dawley rats 3, 5, 10, 32, 90 and 130 weeks of age. Glycosaminoglycans (GAGs) were extracted from the discs by heat treatment, alkali treatment and digestion with Pronase E, and purified by precipitation with cetylpyridinium chloride and ethanol. The concentration of total GAG was highest in the 3 week extracts and tended to decrease with age. Dermatan sulphate was the predominant GAG detected in all age groups along with chondroitin sulphate, hyaluronic acid and heparan sulphate. The disaccharides obtained from chondroitin sulphate were delta Di-4S, delta Di-6S and delta Di-0S, with delta Di-4S being the predominant isomer followed by delta Di-6S for all ages of all the GAG examined. The concentration of chondroitin sulphate showed a decrease with age. Quantitative changes of GAG with age may be related to functional changes in TMJ discs.

Aging↗

PubMed1996

CPA induces a sustained increase in [Ca2+]i of endothelial cells in situ and relaxes porcine coronary artery.

Using fura 2 fluorometry, we investigated the effect of cyclopiazonic acid (CPA), an inhibitor of Ca2+ pump adenosinetriphosphatase of the endoplasmic reticulum, on cystosolic Ca2+ concentration ([Ca2+]i) and tension in porcine aortic valvular endothelial cells and coronary arterial strips with endothelium. In normal physiological salt solution, CPA induced a sustained increase in [Ca2+]i in the valvular strips, whereas in Ca(2+)-free physiological salt solution, CPA elicited a transient elevation of [Ca2+]i. CPA(30 microM) relaxed coronary strips with endothelium precontracted by 100 nM U-46619; this relaxation was partially inhibited by N omega-nitro-L-arginine (100 microM). These results indicate that the CPA-induced increase in [Ca2+]i depends on the Ca2+ release and the Ca2+ influx in the endothelial cells in situ and that the CPA-induced endothelium-dependent decreases in [Ca2+]i and tension in the smooth muscle are due to the combined effect of N omega-nitro-L-arginine-sensitive and -resistant factors.

Animals↗

PubMed1996

[Shichimotsu-koka-to prevents stroke and changes free-radical-related enzymes in stroke-prone spontaneously hypertensive rats (SHRSP)].

Shichimotsu-koka-to, a Chinese herb, is a medicine prescribed to treat patients with hypertension. We investigated the effects of Shichimotsu-koka-to on the lesions of stroke-prone spontaneously hypertensive rats (SHRSP). The SHRSP were given 1% or 2% Shichimotsu-koka-to solution (1 g/kg/day or 2 g/kg/day) instead of drinking water from 8 to 42 weeks of age. When the 2 g/kg/day Shichimotsu-koka-to was chronically administered to the SHRSP, their life span was significantly prolonged by prevention of stroke, but there was no effect on blood pressure. The Shichimotsu-koka-to treatment decreased superoxide dismutase (SOD) activities in the cytosol of the cerebral cortex and increased SOD activities in the cytosol of the brain stem. The treatment with 2 g/kg/day Shichimotsu-koka-to decreased xanthine oxidase (XOD) activities in the cytosol of the cerebral cortex, and Shichimotsu-koka-to quenched superoxide anion (O2-) as determined by electron spin resonance analysis in vitro. In addition, SOD activities in the cytosol of the cerebral cortex of SHRSP not administered Shichimotsu-koka-to were increased by the drug in vitro. XOD activities in the cytosol of the cerebral cortex of SHRSP not administered Shichimotsu-koka-to were inhibited by this herb in vitro. These results suggest that these preventive effects of Shichimotsu-koka-to on the stroke in SHRSP are due its ability to scavenge O2- and to inhibit O2- production by the hypoxanthine-XOD system in the cytosol of the cerebral cortex.

Animals↗

PubMed1996

[An examination of two reporting methods of falls among the elderly living in the community].

This study examined the concordance of two reporting methods for falls (3 month and 12 month recall) experienced by elderly living in a rural community. Four interview surveys on the occurrence of falls over a 3 month period were conducted from 1992 to 1993 every three months. In the final interview, subjects were also asked about the occurrence of falls during the past 12 months. A total of 799 subjects (270 men, 529 women) aged 65 and over, living in a village of Niigata Prefecture, responded to all four surveys. The incidence of falls in one year was 19.0% by the 3 month recall, and 19.1% by the 12 month recall. Overall agreement of fall occurrence between the two methods was 98.9%, and a coefficient of kappa as a measure of concordance was 0.96. On the other hand, subjects who sustained injuries during falls reported in the 3 month reporting did not necessarily recall having a fall when interviewed at the end of the study. In any case, this study reveals that for surveying falls by the elderly living in the community a 1 year recall is a reliable method, because of the high agreement of fall occurrence when comparing the two methods.

Accidental Falls↗

PubMed1996

Clinical evaluation of a dental rinse containing aluminum lactate for treatment of dentinal hypersensitivity.

The effectiveness of a dental rinse containing aluminum lactate, which was used as a daily home treatment for dentinal hypersensitivity, was evaluated in a 6-week, double-blind study. Fifty-six subjects who complained of cold and/or tactile hypersensitivity were randomly divided into two groups: one given a dental rinse containing 2.18% aluminum lactate (test group) and the other a vehicle control dental rinse (control group). Subjects in both groups were instructed to rinse with the assigned dental rinse and to brush their teeth twice daily. The hypersensitivity levels of the affected teeth were assessed at baseline and at 4 and 6 weeks by application of tactile, cold air and cold water stimuli, and scored against baseline. All hypersensitivity scores in both groups were decreased significantly at weeks 4 and 6 compared to the baseline (p < 0.001). The hypersensitivity scores for tactile, cold air and cold water stimuli in the test group were significantly lower at weeks 4 and/or 6 compared to those in the control group (p < 0.05). Furthermore, on the analysis for the teeth with apparent pain (score 2 or 3) at the baseline, the reduction rates of hypersensitivity scores for cold air and cold water stimuli in the test group were significantly greater than those in the control group (p < 0.05). These findings suggest that daily home use of a dental rinse containing aluminum lactate is effective for treatment of dentinal hypersensitivity.

Adult↗

PubMed1995

Structure of the osteopontin gene and its promoter.

We cloned the hOPN gene and its 5' upstream region, and analyzed its exon-intron structure and potential regulatory sequences of the promoter region in comparison with those of mouse and porcine homologues. The hOPN gene consists of 7 exons that are similar to those of the mouse gene, although the hOPN gene is longer than the mouse homologue. This difference is attributable to an insertion of about 1750 bp immediately before exon 4 in the hOPN gene. A region of approximately 285 bp immediately upstream of the hOPN transcription initiation site was highly conserved and contained a number of potential cis regulatory consensus sequences. CAT analysis using SCC-3 cells demonstrated that nucleotides at positions -439 to -270, -124 to -80, and -55 to -39 contained cis-acting enhancing elements, in which the -124 to -80 element was much more active than the others. Deletion of the sequences between -474 and -270 localized the cis elements to the sequence at position -439 to -410, whereas the deletion between -124 to -80 localized it to -124 to -115, and -94 to -80 (data not shown). Gel shift analysis using synthesized double-stranded oligonucleotides corresponding to the 30 bp at position -439 to -410 (data not shown), and 10 and 15 bp regions at positions -124 to -115 and -94 to -80, respectively, as probes revealed that each probe formed one or two bands complexed with a nuclear protein prepared from SCC-3 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Expression of osteopontin in a macrophage cell line and in transgenic mice with pulmonary fibrosis resulting from the lung expression of a tumor necrosis factor-alpha transgene.

The expression level of osteopontin (OPN) mRNA was found to be increased in a macrophage cell line in the presence of recombinant tumor necrosis factor-alpha (TNF-alpha). OPN mRNA level was also explored in the lungs of transgenic mice which were expressing TNF-alpha in type II pneumocytes, a condition leading to pulmonary alveolitis and progressive fibrosis. OPN mRNA was significantly increased in the lungs of these transgenic mice. In situ hybridization showed that it was localized mostly in alveolar macrophages. Since OPN can be induced in macrophages by TNF-alpha stimulation and since on the other hand osteopontin appears to decrease the level of nitric oxide synthase, and thus the production of nitric oxide, osteopontin might also indirectly have an antifibrotic effect. The role played by osteopontin in fibrotic lesions resulting from the release of TNF-alpha deserves further study, since it may be involved in the balance of opposite effects eventually leading to local tissue damage ending in fibrosis.

Animals↗

PubMed1995

Effect of recombinant osteopontin on adhesion and migration of P388D1 cells.

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Amino Acid Sequence↗

PubMed1995

Purification of all forms of HeLa cell mitochondrial DNA and assessment of damage to it caused by hydrogen peroxide treatment of mitochondria or cells.

A purification scheme for mitochondrial DNA (mtDNA) was designed which maximized the yield of all forms of the DNA while minimizing damage to the DNA during its isolation. Treatment of intact mitochondria with DNase I removed nuclear DNA and the avoidance of phenol and the isolation by CsCl density gradients in the absence of ethidium bromide and subsequent detection by Southern Hydridization dot-blots minimized DNA damage. Four different mtDNA forms free of apparent nuclear DNA were obtained: closed circular (I), open circular (II), linear (III), and a large multimer complex (C) which were characterized by agarose gel electrophoresis and electron microscopy. Using this procedure, mtDNA was obtained from both whole cells or intact mitochondria treated with H2O2. Significant fragmentation was observed after treatment at 37 degrees C, but not at 0 degrees C, and more damage was observed when treating whole cells than isolated mitochondria. Very low levels of 8-hydroxydeoxyguanosine were observed in all cases. However, at doses of H2O2 which were just lethal, neither increased DNA damage nor inactivation of cytochrome c oxidase was observed.

Base Sequence↗

PubMed1995

Expression of wild-type and mutated rabbit osteopontin in Escherichia coli, and their effects on adhesion and migration of P388D1 cells.

Recombinant wild-type rabbit osteopontin (rOP) and the protein with an aspartate-to-glutamate transposition induced by a point mutation in the rabbit OP cDNA within the Gly-Arg-Gly-Asp-Ser (GRGDS) sequence were expressed in Escherichia coli and purified to homogeneity. P388D1 cells bound rOP in a saturable manner. rOP induced adhesion and haptotaxis of P388D1 cells, whereas mutated rabbit OP (rOPmut) did not. Anti-rOP IgG F(ab')2 and synthetic GRGDS peptide inhibited rOP-mediated adhesion and haptotaxis of P388D1 cells. Fibronectin (FN)-mediated adhesion of P388D1 cells was markedly inhibited in the presence of fluid-phase rOP. Adhesion of P388D1 cells to rOP was significantly inhibited by anti-[alpha-subunits of VLA4 (alpha 4) and VLA5 (alpha 5)] monoclonal antibodies (mAbs), but not by anti-[alpha-subunit of vitronectin (VN) receptor (alpha V) or Mac-1 (alpha M)] mAb. Adhesion of P388D1 cells to FN and VN was significantly inhibited by anti-alpha V mAb but not anti-alpha 4, -alpha 5 or -alpha M mAb. Haptotaxis of P388D1 cells to rOP was significantly inhibited by anti-alpha V mAb, but not by anti-alpha 4, -alpha 5 and alpha M mAbs, whereas that to FN showed no inhibition with all three mAbs. Haptotaxis of P388D1 cells to VN was significantly inhibited by anti-alpha 5 and -alpha V mAbs but not by anti-alpha 4 and -alpha M mAbs. Similar features of inhibition of adhesion and haptotaxis of P388D1 cells to human OP were observed by mAbs. rOP had no chemotactic effect on P388D1 cells. Significant polymorphonuclear leucocyte migration was observed 3-12 h after intradermal injection of rOP into rabbits.

Amino Acid Sequence↗

PubMed1995

Polypoid growth and K-ras codon 12 mutation in colorectal cancer.

BACKGROUND: To clarify genetic changes in colorectal tumorigenesis, K-ras codon 12 point mutations were examined in 101 ordinary colorectal carcinomas and 6 that complicated ulcerative colitis (UC) with special attention to growth patterns. METHODS: The depths of invasion of ordinary carcinoma were submucosa (SMCa) in 39 cases, muscularis propria (PMCa) in 33, and far-advanced in 29. Growth patterns of SMCa and PMCa were classified into three types: polypoid-growth type without central depression (Type 1), polypoid-growth type with central depression (Type 2), and nonpolypoid-growth type. DNA samples were extracted from formalin fixed paraffin embedded sections, and K-ras codon 12 mutations were examined by two-step polymerase chain reaction-restriction fragment length polymorphism. RESULTS: K-ras mutation frequency was higher in Type 1 SMCa than in nonpolypoid SMCa, 56% (9/16) versus 6% (1/17), respectively, and in PMCa, 78% (7/9) versus 23% (3/13), respectively. In 6 UC carcinomas, a K-ras mutation was detected in only one polypoid carcinoma and none were detected in five nonpolypoid carcinomas. CONCLUSIONS: These results and the authors' previous study suggest that nonpolypoid carcinomas may be derived from flat adenomas, whose K-ras mutation incidence also was low, and this pathway is different from a genetic model based on the ordinary adenoma-carcinoma sequence through polypoid adenomas.

Adenoma↗