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A Amano

Publications and source records attributed to A Amano.

At least 73 records · Page 4Linked to original sources
PubMed1997

Active sites of salivary proline-rich protein for binding to Porphyromonas gingivalis fimbriae.

Porphyromonas gingivalis fimbriae specifically bind salivary acidic proline-rich protein 1 (PRP1) through protein-protein interactions. The binding domains of fimbrillin (a subunit of fimbriae) for PRP1 were analyzed previously (A. Amano, A. Sharma, J.-Y. Lee, H. T. Sojar, P. A. Raj, and R. J. Genco, Infect. Immun. 64:1631-1637, 1996). In this study, we investigated the sites of binding of the PRP1 molecules to the fimbriae. PRP1 (amino acid residues 1 to 150) was proteolysed to three fragments (residues 1 to 74 [fragment 1-74], 75 to 129, and 130 to 150). 125I-labeled fimbriae clearly bound fragments 75-129 and 130-150, immobilized on a polyvinylidene difluoride membrane; both fragments also inhibited whole-cell binding to PRP1-coated hydroxyapatite (HAP) beads by 50 and 83%, respectively. However, the N-terminal fragment failed to show any effect. Analogous peptides corresponding to residues 75 to 89, 90 to 106, 107 to 120, 121 to 129, and 130 to 150 of PRP1 were synthesized. The fimbriae significantly bound peptide 130-150, immobilized on 96-well plates, and the peptide also inhibited binding of 125I-labeled fimbriae to PRP1-coated HAP beads by almost 100%. Peptides 75-89, 90-106, and 121-129, immobilized on plates, showed considerable ability to bind fimbriae. For further analysis of active sites in residues 130 to 150, synthetic peptides corresponding to residues 130 to 137, 138 to 145, and 146 to 150 were prepared. Peptide 138-145 (GRPQGPPQ) inhibited fimbrial binding to PRP1-coated HAP beads by 97%. This amino acid sequence was shared in the alignment of residues 75 to 89, 90 to 106, and 107 to 120. Six synthetic peptides were prepared by serial deletions of individual residues from the N and C termini of peptide GRPQGPPQ. Peptide PQGPPQ was as inhibitory as peptide GRPQGPPQ. Further deletions of the dipeptide Pro-Gln from the N and C termini of peptide PQGPPQ resulted in significant loss of the inhibitory effect. These results strongly suggest that PQGPPQ is the minimal active segment for binding to P. gingivalis fimbriae and that the moiety of the Pro-Gln dipeptide plays a critical role in expressing binding ability.

Bacterial Adhesion↗
PubMed1997

Prophyromonas gingivalis fimbriae mediate coaggregation with Streptococcus oralis through specific domains.

Fimbriae are major adhesive components on the cell surface of Prophyromonas gingivalis. In this study, we evaluated the role of fimbriae in coaggregation with Streptococcus oralis. Fimbriae purified from P. gingivalis competitively inhibited the coaggregation by 100% at a concentration of 50 micrograms/mL. On the other hand, the same amount of lipopolysaccharide isolated from P. gingivalis was inhibited by only 25% of the level of the fimbriae. A fimA-inactivated mutant of P. gingivalis failed to show distinct coaggregation activity. Fimbriae added to a solution of various strains of streptococci caused their self-aggregation at a concentration of 10 to 30 micrograms/mL. The self-aggregation induced by fimbriae was inhibited by lambda-arginine (20 to 40 mM/L). Iodinated fimbriae reacted with S. oralis cells immobilized on the nitrocellulose membrane, and 100 degrees C heating of the cells diminished the binding abilities. Recombinant fimbrillin (r-Fim, corresponding to whole residues 1 to 337 of native fimbrillin) of P. gingivalis also showed 100% inhibition of the coaggregation. The r-Fim variant (residues 1 to 286) lacking the C-terminal 51 residues was as inhibitory as r-Fim. However, the variant (residues 1 to 265) without the C-terminal 72 residues lost 77% of the inhibitory activity. These findings suggested that residues 266 to 286 contain a domain involved in the coaggregation of P. gingivalis with S. oralis. Inhibition by three polypeptides corresponding to residues 266 to 286, 266 to 337, and 287 to 337 was studied. Peptides 266 to 286 and 266 to 337 inhibited by 96 and 100%, respectively, at a concentration of 1.5 nmol/mL. Peptide 287 to 337 also showed a significant inhibitory effect but to a slightly lesser extent than that of peptide 266 to 286. P. gingivalis fimbriae appear to be involved in coaggregation with streptococci, probably through an adhesive protein molecule(s) of the latter, and the fimbriae possess several domains in the C-terminal residues 266 to 337 for interaction with S. oralis.

Bacterial Adhesion↗
PubMed1997

[Coronary artery bypass grafting with arterial grafts in the elderly patients].

One hundred six consecutive patients aged 75 years and over (mean age 77.1, 75-84) underwent coronary artery bypass. Controlled group is 287 patients undergoing CABG in 1996. The number of bypass graft, arterial graft, Ao-cross clamp time, CPB time, operation time in aged group and controlled group were as follows 3.3 and 3.3, 1.9 and 2.5 (p < 0.01), 106 and 104, 333 and 328. The number of anastomose per patients with LITA, SVG, GEA, RITA, IEA, RA, as follows 1.0 and 1.0, 1.5 and 0.5, 0.6 and 0.5, 0.1 and 0.14, 0.03 and 0.03, 0.2 and 3.3 SVG were used significantly high and RA were used low in aged group. Sequential bypass were under went 30.1% in aged group and 35.5% in controlled group. There was no operative death in elective operation, 5 (4.9%) was died in emergent operation. A favorable outcome may be expected when coronary bypass surgery with arterial graft is performed in 75 years and over aged group.

Age Factors↗
PubMed1996

Gastroepiploic artery graft in 400 patients.

The right gastroepoploic artery (GEA) has been used for coronary artery bypass grafting (CABG) in 400 patients of a total of 1359 undergoing the same procedure during an 8-year period. There were 327 males and 73 females with a mean age of 59 years. Single-, double- and triple-vessel and left main disease were noted in 4, 51, 283 and 62 patients, respectively. Previous myocardial infarction was noted in 208 patients and 40 patients had undergone previous CABG. Internal thoracic artery (ITA) and inferior epigastric artery grafts were concomitantly used in 388 (97%) and 30 (8%) patients, respectively. The mean number of grafts was 3.2 including vein grafts, and 2.3 coronary arteries were bypassed with arterial grafts. The sites of GEA grafting were 43 anterior descending, 6 diagonal, 71 circumflex, and 287 right coronary arteries with 376 in situ and 24 free grafts including 7 sequential grafts. There were eight (2%) early and five (1.3%) late deaths. New Q waves were noted in six (1.5%) patients. Warm body circulation is thought to be favorable with a lower incidence of the need for intra-aortic balloon pump (0.6% vs 6.0%). Postoperative angiography revealed 94% (253/268) early (2 months) and 94% (47/50) late (2-5 years) patency of GEA grafts. In conclusion. GEA is a safe and effective arterial conduit for CABG.

Abdominal Muscles↗
PubMed1996

Binding sites of salivary statherin for Porphyromonas gingivalis recombinant fimbrillin.

We investigated the binding sites of salivary statherin involved in the interaction with Porphyromonas gingivalis recombinant fimbrillin (r-Fim). Synthetic peptides representing statherin analogs were used to localize the binding domains of statherin. Peptide F4 (residues 29 to 43) significantly bound to r-Fim and inhibited r-Fim binding to statherin-coated hydroxyapatite beads. Successive peptides in which pairs of amino acid residues were deleted starting at the N terminus of peptide F4 were synthesized. Peptide N1 without Leu-29-Tyr-30 had significantly reduced direct binding and inhibition ability. The deletions of residues 31 to 40 had little effect on interaction with r-Fim. The tripeptide N6 representing Tyr-41-Thr-42-Phe-43 retained significant binding to r-Fim. Another set of peptides was synthesized by deleting individual amino acid residues from the C and N termini of peptide F4 to identify functional residues among the five putative functional residues 29, 30, and 41 to 43. Peptide C1 missing Phe-43 lost over 50% of its binding ability. Binding ability was gradually reduced with deletions from the peptides. Peptide C5 (amino acids 31 to 40) weakly affected direct binding and inhibition. Collectively, the results of this study suggests that Leu-29-Tyr-30 and Tyr-41-Thr-42-Phe-43 are important binding regions that mediate the binding of statherin to P. gingivalis fimbrillin.

Amino Acid Sequence↗
PubMed1996

Structural domains of Porphyromonas gingivalis recombinant fimbrillin that mediate binding to salivary proline-rich protein and statherin.

Fimbriae (the oligomeric form of fimbrillin) are considered important in the adherence and colonization of Porphyromonas gingivalis in the oral cavity. In the present study, we have identified the structural domains of P. gingivalis fimbrillin that mediate the binding to salivary proline-rich protein 1 (PRP1) and statherin. A series of synthetic fimbrillin peptides were used to localize the active fimbrillin domains involved in the binding to PRP1 and statherin. The binding of 125I-labeled 41-r-Fim (whole-length recombinant fimbrillin, amino acid [aa] residues 1 to 337) to PRP1-coated hydroxyapatite beads (HAP) was strongly inhibited by the fimbrillin C-terminal peptides corresponding to aa residues 266 to 286 and 318 to 337 (peptides 266-286, and 318-337, respectively), while the binding to statherin was inhibited by C-terminal peptides 266-286, 293-306 and 307-326. Peptide 126-146 also showed a weak inhibitory effect, about half that of other active peptides, on the binding to both PRP1 and statherin. P. gingivalis whole-cell binding to PRP1- or statherin-coated HAP was inhibited by more than 80% by the same active peptides. To confirm that the C-terminal portion of fimbrillin includes domains responsible for the binding, two C-terminally truncated variants of recombinant fimbrillin were generated and purified. These were designated 34.5-r-Fim, corresponding to aa residues 1 to 286, and 32-r-Fim, corresponding to aa residues 1 to 265. 125I-34.5-r-Fim revealed 35 and 34% loss of binding ability to PRP1 and statherin, respectively. 125I-32-r-Fim had significantly less binding ability to PRP1 and statherin than 125I-34.5-r-Fim, which was reduced 78 and 73%, respectively. Whole-cell binding to PRP1-, statherin-, or whole saliva-coated HAP was inhibited up to 100% by 41-r-Fim, while 32-r-Fim also showed considerable inhibition, possibly due to the region of aa 126 to 146. Collectively, these results suggest that there are separate and multiple binding sites for PRP1 and statherin in the P. gingivalis fimbrillin, and the combination of all of these binding sites may be indispensable in establishing stable bacterial adherence to saliva-coated surfaces in the oral cavity.

Amino Acid Sequence↗
PubMed1996

Porphyromonas gingivalis reduces mitogenic and chemotactic responses of human periodontal ligament cells to platelet-derived growth factor in vitro.

The effects of a sonicated Porphyromonas gingivalis ATCC 33277 protein extract on the mitogenic and chemotactic responses of human periodontal ligament (PDL) cells to the recombinant human platelet-derived growth factor-BB homodimer (PDGF-BB) were examined in vitro. Proliferation of PDL cells was inhibited by P. gingivalis extract at concentrations higher than 10 micrograms/mL protein. At 100 micrograms/mL of P. gingivalis extract, cells did not proliferate. DNA synthesis in PDL cells, as revealed by [3H]-thymidine incorporation, was also inhibited by approximately 50% in the presence of 50 micrograms/mL P. gingivalis extract for 24 hours. In contrast, PDGF-BB at 1 ng/mL enhanced DNA synthesis in PDL cells, followed by maximum enhancement at concentrations higher than 10 ng/mL PDGF-BB. However, this mitogenic response to PDGF-BB was markedly reduced in the presence of 20 micrograms/mL of P. gingivalis extract and did not reach the maximum level even if PDGF-BB concentrations were increased to 250 ng/mL. PDL cells exhibited a chemotactic response to PDGF-BB at 1 ng/mL, which was also inhibited by pretreatment of the cells with P. gingivalis extract at 10 to 50 micrograms/mL. Scatchard analysis of a [125I]-PDGF binding assay demonstrated that PDL cells have both high and low PDGF binding affinity sites. Treatment of the cells with P. gingivalis extract decreased the number of PDGF-binding sites to approximately 35% of the control level, while it caused only a slight change in the affinities of both types of binding site. These results indicated that the P. gingivalis extract reduced mitogenic and chemotactic responses of human PDL cells, possibly through mechanisms involving a decrease in PDGF-binding capacity of these cells. Due to this inhibitory effect of P. gingivalis, the normal levels of PDGF in periodontal lesions may not be sufficient to promote periodontal regeneration through activation of PDL cell proliferation and migration. Therefore, the therapeutic use of PDGF-BB, as a supplement to pre-existing PDGF and as an adjunct, while also eliminating P. gingivalis from periodontal lesions, would help periodontal tissue regeneration.

Bacterial Proteins↗
PubMed1995

Binding of hemoglobin by Porphyromonas gingivalis.

In this study, we investigated whether Porphyromonas gingivalis can bind hemoglobin as an initial step in the acquisition of heme from hemoglobin. The binding of human hemoglobin by P. gingivalis cells was determined using [3H]hemoglobin. Hemoglobin binding occurred rapidly, reversibly and specifically. A Scatchard analysis of the binding data generated a linear plot, indicating a single population of binding proteins. The apparent Kd was 1.0 +/- 0.19 x 10(-6) M and there were 3.2 +/- 0.76 x 10(4) binding sites per cell. Hemoglobin binding was inhibited by unlabeled human hemoglobin but not by hemin and protoporphyrin IX. The binding was only partially inhibited by human serum albumin, transferrin, lactoferrin, catalase and cytochrome c. These results suggest that the ligand recognized by the binding protein may not be the heme moiety. The binding of hemoglobin considerably increased when the organisms were grown under hemin-limited conditions. Hemoglobin bound to outer membrane proteins extracted from P. gingivalis cells on a dot blot binding assay and binding ability was lost after heating bacterial proteins. These results suggest that P. gingivalis cells interact with human hemoglobin through specific binding sites on their surfaces as a preliminary step in iron acquisition.

Bacterial Outer Membrane Proteins↗
PubMed1995

Effect of concentration of compounds containing iron on the growth of Porphyromonas gingivalis.

We examined the effect of the concentration of various types of iron molecules on the regulation of growth of Porphyromonas gingivalis. Bacterial growth was monitored spectrophotometrically. The hemin-depleted cells of P. gingivalis 381 were incubated in the basal medium plus test substrates such as hemoglobin, hemin, transferrin and various inorganic iron compounds. The relationship between the specific growth rate of organisms and the concentration of iron-containing compounds was determined. The value of Ks, a parameter analogous to the Michaelis-Menten constant, was estimated. P. gingivalis 381 showed a Ks value of 3.85, 4.91 and 0.0017 microM for hemin, transferrin and hemoglobin, respectively. However, the inorganic iron compounds tested did not support growth of P. gingivalis. These findings suggest that P. gingivalis utilizes hemoglobin as an iron source much more effectively than other iron-containing compounds under an iron-limited environment.

Culture Media↗
PubMed1995

Interaction of Porphyromonas gingivalis with transferrin.

In this study, we characterized the binding of transferrin to Porphyromonas gingivalis using a classical receptor-binding assay, and examined the relationship between the binding and availability of transferrin for the growth of P. gingivalis. The binding of 125I-labeled human transferrin to P. gingivalis occurred rapidly, reversibly and specifically. Scatchard analysis yielded a Kd of 1.37 +/- 0.16 microM and an apparent number of 1.13 +/- 0.26 x 10(5) receptors per cell. The binding of transferrin was much increased when organisms were grown in iron-limited conditions. Among the species of black-pigmented anaerobic.rods, those strains of P. gingivalis which had high transferrin-binding activity exhibited unrestricted growth following the addition of transferrin to the hemin-free culture medium. On the other hand, the presence of transferrin in the culture medium did not support unrestricted growth of organisms that had low transferrin-binding activity. These results suggest that the binding of transferrin to P. gingivalis cells may be a preliminary step in iron acquisition, which allows them to survive in the healthy periodontal environment.

Animals↗
PubMed1995

Purification of major fimbrial proteins of Porphyromonas gingivalis.

Binding of Porphyromonas gingivalis to pellicle-coated teeth is mediated to a large extent by fimbrillin, a major structural subunit of fimbriae. A simple and efficient method for purifying the major fimbrial proteins from various strains of P. gingivalis was developed. The sonic extracts of crude fimbriae were prepared from P. gingivalis strains 2561, A7A1-28, EM-3, and 9-14K-1, which are representatives of different fimbrial groups. The crude fimbriae were precipitated from the extracts with 40% saturated ammonium sulfate. The dialyzed crude fimbriae were dissolved in 8 M guanidine HCl and loaded onto a Sepharose CL-6B column equilibrated with 6 M guanidine HCl. The major fimbrial protein-enriched fractions were obtained and further purified to homogeneity by repetitive gel filtration on the same column. The purity and intactness of the purified fimbrial proteins were ascertained by SDS-polyacrylamide gel electrophoresis followed by silver nitrate staining and immunoblot analysis using rabbit antisera raised against the purified fimbrial proteins. The result demonstrates the usefulness of guanidine HCl as a reliable reagent for purifying various fimbrial proteins of P. gingivalis, which are often associated strongly with other outer membrane proteins and show different physicochemical and antigenic characteristics.

Ammonium Sulfate↗
PubMed1995

[Rehabilitation in rheumatoid arthritis (RA) patients--assessment of effects of rehabilitation based on activities of daily living (ADL)].

The 37 hospitalized RA patients undergoing rehabilitation (for 4 weeks) were evaluated on effects of rehabilitation by comparing scores of ADL at the time of admission and discharge. Items of ADL were composed of 32. Items of ADL which were likely to be disabled were related to those of ADL which were influenced by rehabilitation (r = 0.7412, p < 0.01). From this result, 11 items of ADL which were likely to be disabled and influenced by rehabilitation could be selected in order. Usefulness of these selected items of ADL on evaluation of rehabilitation was admitted.

Activities of Daily Living↗
PubMed1994

Porphyromonas gingivalis trypsin-like protease: a possible natural ligand for the neutrophil formyl peptide receptor.

Porphyromonous gingivalis is a periodontopathic Gram-negative anaerobe associated with chronic adult periodontitis. P. gingivalis proteases are considered important virulence factors in the pathogenesis of periodontal diseases. In addition, defective bactericidal activity of neutrophils has also been observed in periodontitis. In this report we describe the effects of trypsin-like protease(s) secreted from P. gingivalis cells on the ligand binding of FMLP receptor on neutrophils. It was observed that trypsin-like protease(s) from P. gingivalis stimulate neutrophils by means of superoxide anion production. Subsequently, the proteases were found to cleave the FMLP receptor protein as evident by direct labeling of the FMLP receptor molecule. These results suggest that trypsin-like protease(s) secreted from P. gingivalis cells contribute to attenuate the bactericidal activity of neutrophils by cleaving the polypeptide chain of the FMLP receptor molecule. The finding that neutrophils after the incubation with P. gingivalis released protease preparation fail to respond to further stimulation by FMLP suggests that P. gingivalis trypsin-like protease(s) may be a possible ligand for the FMLP receptor.

Affinity Labels↗
PubMed1994

Histological studies on the rheumatoid synovial membrane irradiated with a low energy laser.

The beneficial effects of low energy laser irradiation on rheumatoid arthritis (RA) joints have been reported, but the mechanisms of action of low energy lasers in RA are unclear. The synovial membrane in cases of RA was studied histologically to observe the effects of low energy laser irradiation. Fourteen knee joints of RA cases, which had been scheduled for arthroplasty, were irradiated with a gallium-aluminium-arsenide (Ga-Al-As) laser (790 nm in wavelength and 10 mW of output power) prior to the surgical operation, at six points of the external aspect of the knee joint for 80 seconds at each points once a day for 6 days. On the day following the last irradiation, pieces of synovial membrane from the lateral irradiated area and from the median nonirradiated area as a control were resected during the arthroplasty. The histological findings of the irradiated synovial membrane showed flattening of epithelial cells, decreased villous proliferation, narrowed vascular lumen, and less infiltration of inflammatory cells compared with those of nonirradiated synovia. The evaluation of slides was done in a blinded manner, and significant differences was seen by Wilcoxon's t-test (P < 0.01). Histological findings suggested that the low energy laser irradiation induced suppression of inflammation in the synovial membrane of RA.

Arthritis, Rheumatoid↗
PubMed1994

Gastroepiploic artery graft for anterior descending coronary artery bypass.

In 308 right gastroepiploic artery (GEA) grafting procedures performed for myocardial revascularization, 38 GEA, 34 in situ, and four free grafts were used to bypass the left anterior descending coronary artery (LAD). Indications for using the GEA for the purpose of LAD bypass were: unavailability of the internal thoracic artery (ITA) at reoperation, surgical damage to the ITA at the time of the operation, or an apparently better free flow versus that in the left ITA, particularly in patients with diabetes mellitus in whom it was considered inadvisable to use bilateral ITAs. There were 21 male and 17 female patients with a mean age of 62 years (range, 31 to 77 years). Ten patients had undergone a previous myocardial revascularization. The mean number of distal anastomoses was 2.8 (range, 1 to 5). Concomitantly used conduits were the ITA in 27 patients, saphenous veins in 21 patients, the inferior epigastric artery in 4 patients, and the bovine internal thoracic artery in 1 patient. All but 1 patient survived. Follow-up ranged from 3 to 84 months (mean, 27 months). Postoperative angiography was performed in 33 patients. At the short-term evaluation (mean, 1 month), 32 of 33 (97%) GEA grafts were found to be patent; all 4 GEA grafts studied at the long-term evaluation (mean, 25 months) were also found to be patent. In no patients did angina recur postoperatively. In 25 patients who underwent an exercise study postoperatively, the stress test results were negative in 23.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1994

Effect of binding of fibrinogen to each bacterium on coaggregation between Porphyromonas gingivalis and Streptococcus oralis.

Fibrinogen inhibits the coaggregation between Porphyromonas gingivalis and Streptococcus oralis. In this study, we determined which bacterium interacts with fibrinogen in this inhibitory process. Although preincubation of each bacterium with fibrinogen did not inhibit coaggregation, its activity was completely eliminated by the addition of protease inhibitors such as N-ethylmaleimide (NEM), p-chloromercuriphenyl sulfonate and N alpha-p-tosyl-L-lysine chloromethyl ketone to the preincubation mixture with fibrinogen and P. gingivalis. However, the inhibition of coaggregation was not found after preincubation of S. oralis with fibrinogen in the presence or absence of the protease inhibitors. Labelled materials were recovered from the extract of P. gingivalis cells incubated with radioiodinated fibrinogen in the presence of NEM but not in the absence of NEM. In the binding experiment, P. gingivalis showed a much higher binding activity to fibrinogen than S. oralis. These findings suggest that fibrinogen and its fragment(s) may mask directly or indirectly the aggregation site with S. oralis on the P. gingivalis cells in its inhibitory process of coaggregation.

Bacterial Adhesion↗
PubMed1994

Effects of temperature stress on expression of fimbriae and superoxide dismutase by Porphyromonas gingivalis.

We examined the biosynthesis of fimbriae and superoxide dismutase (SOD) produced by the periodontopathic bacterium Porphyromonas gingivalis in response to elevated temperature. P. gingivalis 2561, grown at 37 degrees C to mid-logarithmic phase, was subsequently incubated at 39, 41, and 43 degrees C, respectively, to stationary phase. There was no difference in the growth of cells at 37 and 39 degrees C. However, at 39 degrees C there was a 54% reduction in the amount of fimbrillin (fimbriae) as well as decreased expression of mRNA for fimA. On the other hand, under the same conditions, a more than twofold increase in the amount of SOD activity, as well as in the levels of SOD mRNA, was observed. Moreover, cells cultured for 20 h at 39 degrees C showed an 86% decrease of fimbrillin protein and a threefold increase in SOD activity. These observations suggest that P. gingivalis may undergo alterations in its virulence and susceptibility to host immune responses as a result of the elevated temperatures found in inflamed periodontal pockets.

Bacterial Proteins↗