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Biomedical subjects

F Nishimura

Publications and source records attributed to F Nishimura.

At least 91 records · Page 5Linked to original sources
PubMed1991

Isolation and partial characterization of a 39 kDa major outer membrane protein of Actinobacillus actinomycetemcomitans Y4.

The outer membrane fractions of Actinobacillus actinomycetemcomitans, which were extracted from whole cells with cetyl trimethyl ammonium bromide and CaCl2, contained four major outer membrane proteins (MOMP) of 39, 37, 36 and 30 kDa. The 39 kDa MOMP of A. actinomycetemcomitans was sequentially purified by extraction with Zwittergent 3-14 detergent, anion-exchange chromatography and gel filtration chromatography. Analysis of amino acid composition and N-terminal amino acid sequence of 20 residues of purified 39 kDa MOMP was performed. Although some of the periodontitis patient sera reacted strongly with 39 kDa and 30 kDa MOMP in crude outer membrane fractions, purified 39 kDa MOMP showed decreased immunoreactivity with the human sera.

Actinobacillus↗
PubMed1991

Humoral immune response to an antigen from Porphyromonas gingivalis 381 in periodontal disease.

The humoral immune responses of patients with periodontitis were evaluated to characterize the host response to Porphyromonas gingivalis. A sonic extract of P. gingivalis 381 from whole cells was fractionated by gel chromatography and ion-exchange chromatography. The fractionated extracts were evaluated by Western blot (immunoblot) analyses with patient sera. A dominant antigen was identified from the sonic extract with an apparent molecular mass of 53 kDa. The 53-kDa protein antigen (Ag53) was purified by affinity chromatography by using a monoclonal antibody. Ag53 was detected on the vesicle surface of P. gingivalis 381 by immunoelectron microscopy by using the monoclonal antibody and was detected as a major protein in the outer membrane and in vesicles by Western blot analysis. Monoclonal antibody cross-reactivity to Ag53 in the sonic extracts of P. gingivalis ATCC 33277, P. gingivalis 1021, and Porphyromonas endodontalis ATCC 35406 was revealed. Seventy-seven patients with periodontitis were examined for their responses to Ag53. Serum immunoglobulin G (IgG) from 54 patients reacted strongly to Ag53; however, serum IgG from the remaining 23 patients did not exhibit detectable reactivity at all to Ag53, even though the patients had high serum IgG titers to the sonic extract. Ag53 is a new marker that represents an interesting aspect of the humoral immune response to P. gingivalis in patients with periodontitis.

Antibodies, Bacterial↗
PubMed1990

Advantage of cine-MR imaging for the evaluation of valvular regurgitation.

It is well known that the regurgitant blood flow of valvular disease shows a low intensity signal (LS) in cine-MR imaging (cMRI). To determine the significance of cMRI in evaluation of valvular regurgitation, 104 patients who had been assessed by cineangiography also underwent oblique cMRI for mitral regurgitation (MR) and aortic regurgitation (AR), and transverse cMRI for tricuspid regurgitation (TR). In evaluating the accuracy of diagnosis of valvular regurgitation on the basis of the presence of LS in the recipient chamber, sensitivity was found to be 93.5% for MR, 100% for AR and 85.7% for TR; specificity was 76.9% for MR and 100% for AR. The length and area of LS were planimetered in any view with the largest area, and its ratios to the length and area of the recipient chamber of view were calculated. Each index was significantly higher than the degree calculated by cineangiography. The best correlation with angiography was the ratio of the area of LS to the recipient chamber, and a semiquantitative classification by the index was coincident with angiographic severity in 38 of 43 (88.4%) patients undergoing MR, and in 28 of 30 (93.3%) patients undergoing AR. Thus, cMRI is a clinically useful noninvasive method in the identification and semiquantitative assessment of regurgitation severity.

Aortic Valve Insufficiency↗
PubMed1990

A family study of a mother and daughter with increased susceptibility to early-onset periodontitis: microbiological, immunological, host defensive, and genetic analyses.

Microbiological, immunological, host-defensive, and genetic analyses were performed on a mother and daughter, both of whom had early-onset periodontitis (rapidly progressive periodontitis in the mother; localized juvenile periodontitis in the daughter). Microscopic examination revealed a greatly elevated percentage of rod-form bacteria in both subjects. Fusobacterium sp. and Porphyromonas gingivalis (formerly Bacteroides gingivalis) were the predominant microorganisms cultured. The humoral immune responses to F. nucleatum, P. gingivalis, and Actinobacillus actinomycetemcomitans were much higher in both subjects than those to any other periodontal bacteria examined. Functional and phenotypic analysis of the peripheral lymphocytes showed no significant abnormalities. However, investigation of neutrophil function showed that the mother had depressed neutrophil chemotaxis and superoxide production. The daughter had depression not only of chemotaxis and superoxide production, but also of neutrophil phagocytosis. Serological typing of HLA antigens revealed the same Class II HLA profile in both subjects. It was concluded that both subjects very probably had an identical condition and that these patients provided a unique model for improving our understanding of the host factors involved in periodontal disease.

Adolescent↗
PubMed1990

Purification and characterization of two major outer membrane proteins from Porphyromonas gingivalis.

Outer membrane proteins (OMPs) were extracted from whole cells of several Porphyromonas and Prevotella strains and their OMPs profiles were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The SDS-PAGE analysis revealed that OMP profiles of Porphyromonas and Prevotella strains show species-specific patterns and P. gingivalis characteristically had two kinds of major outer membrane proteins (MOMPs). A 53 Kd MOMP from P. gingivalis FDC 381 and a 67 Kd MOMP from ATCC 33277 were purified. Sera from periodontitis patients and healthy subjects were analyzed for immunoreactivities against both the purified MOMPs of P. gingivalis by immunoblotting analysis. The sera from 18 patients reacted to the 53 Kd MOMP, 10 to the 67 Kd MOMP, and only three sera reacted to both MOMPs. The sera of healthy subjects also reacted, but weakly, to either the 53 Kd or 67 Kd MOMP. The SDS-PAGE OMP profiles prepared from 13 clinical isolates of P. gingivalis and immunoblotting analysis of human sera against the two kinds of P. gingivalis MOMPs indicate that periodontal diseases resulting from P. gingivalis are initiated and sustained by at least two MOMPs of P. gingivalis.

Bacterial Outer Membrane Proteins↗
PubMed1990

[Effect of addition of calcia on the properties of zirconia investments].

The zirconia investments with calcia were studied of the compressive strength, setting expansion, thermal expansion, total expansion, thermogravitometry, differential thermal analysis on fabrication method, concentration, particle size of zirconia, calcia and mixing liquid. Addition of calcia caused the change from contraction to expansion in setting expansion. The optimum concentration of calcia was determined to be 10 mol% as judged from total expansion, strength and operability.

Calcium↗
PubMed1990

[Fracture toughness of human enamel irradiated by CO2 laser].

The fracture toughness (KIC) of human enamel irradiated by CO2 laser was examined by means of indentation microfracture method (IM method). The irradiation of laser from 1.5 watt (16 J/cm2) to 12.3 watt (133 J/cm2) was applied to enamel for 0.2 s, and the diamond cone of micro vickers hardness tester was pressed down by the 2.45 N (250 gf) under ordinary circumstances. At the irradiated spot, KIC was 0.24-0.86 MPam1/2 and Hv was 3.6 x 10(3)-4.3 x 10(3)MPa (370-440). At the non-irradiated spot, KIC was 0.83-0.9 MPam1/2 and Hv was 3.9 x 10(3)-4.3 x 10(3)MPa (400-440). A decreasing tendency of KIC was seen in all irradiated spots. The marked decrease of KIC started at the irradiation of 4.4 watt (47 J/cm2) and the rate of decrease was 22%, and 54% when exposed to the irradiation of 5.7 watt (61 J/cm2). The rate of the lowering of the KIC of 0.05 seconds' irradiation x 4 times was less than that of 0.2 s x 1 time, while cumulative total irradiation energy was equal. The measurement of KIC by the low force of 0.98 N (100 gf) seemed to be possible when KIC was 0.41 MPam1/2 and less.

Dental Enamel↗
PubMed1990

[Casting accuracy and shrinkage of titanium castings made with zirconia investments].

To obtain inlay, crown and bridge types of titanium castings with sufficient size accuracy, zirconia investments with 10 mol % calcia were studied for their setting expansion, thermal expansion, total expansion, casting shrinkage compensation deficiency on fabrication method, particle size of zirconia, calcia and mixing liquid. Addition of calcia caused the change from contraction to expansion in setting and the additional thermal expansion at 900-1,200 degrees C. The choice of calcia and mixing liquid makes great influence on setting expansion, which is grouped into saturation type and delayed expansion type. By the use of the saturation type, total expansion could be controlled in the range of -2-(+)3%. Titanium castings of inlay, crown, bridge types with the values -2-(+)2% of casting shrinkage compensation deficiency could be successfully obtained. The casting shrinkage of titanium was estimated as 1.8-2%. The castings have the surface with a metallic brilliance as cast.

Calcium↗
PubMed1990

[Fatigue of dental zinc phosphate cement].

The fatigue characteristics of a zinc phosphate cement were examined. Using a split mould made of stainless steel, 12 mm x phi 6 mm column shape specimens were prepared. Fatigue tests were done by loading partially repeated pulsating diametrical tensile stress of 1-20 Hz, minimum stress was 0.2 MPa (2.0 kgf/cm2) and maximum stress was 3.5-5.4 MPa (36-55 kgf/cm2). During testing, the specimen was kept under distilled water. The existence of a fatigue was confirmed and there were marked signs of fatigue on the fracture surface. The relation between maximum stress and the number of cycles to fracture (S-N diagram) was obtained. Therefore the following equation and fatigue parameter (n) were deduced. logS + 0.0775.logN = 0.8931 n = 12.9 The fatigue characteristics depended on the frequency, that is, a time to fracture was shorter at the loading frequency of 20 Hz than that of 1 Hz.

Materials Testing↗
PubMed1989

[Application of synthetic hydroxyapatite to periodontal therapy].

The purpose of the present study was to evaluate the effectiveness of granular hydroxyapatite as an alloplastic bone implant material in infrabony periodontal defects. Thirty-five infrabony defects in 28 subjects with marginal periodontitis were used. The patients were instructed in oral hygiene and received several sessions of scaling and root planing. Granular hydroxyapatite was implanted into test sites with infrabony defects following application of internally beveled full thickness flaps, root planing, and defect debridement. Pocket depth and attachment level were recorded before and 3 and 6 months after surgery. Gingival recession, mobility of the tooth, plaque index, and gingival index were also recorded before and 1 and 2 weeks, and 1, 3 and 6 months after surgery. Redness and swelling of the gingiva and increase in tooth mobility appeared transiently after surgery, however, they disappeared in a short time. A significant reduction of mean pocket depth of 3.4 mm and a significant increase in the mean attachment level of 2.5 mm were observed at 6 months after surgery. The mean gingival recession during the experimental period was only 0.9 mm. The amount of hydroxyapatite remaining implanted in the infrabony defect was 73% 6 months after surgery. The data and clinical impression suggest that hydroxyapatite has a potential as an alloplastic implant with clinically apparent acceptance by soft and hard tissue.

Bone Resorption↗
PubMed1989

[Setting characteristics of calcia-bonded investments by hydration].

Calcium oxide (CaO) slurry mixed with water hardens and expands by hydration. The authors used this setting characteristic as a binder of zirconia-refractory investments. If a mixed slurry was placed in air, unreacted residual calcia powders absorbed water and reverted to calcium hydroxide (Ca (OH)2). This resulted in a large setting expansion that continued for several days. A carbon dioxide (CO2) gas atmosphere controlled this expansion of calcia. When mixed slurry was placed in a carbon dioxide gas atmosphere, calcium carbonate (CaCO3) was formed and prevented the further hydration of unreacted calcium oxide. Thus setting expansion values were controlled. The combined expansion of setting and thermal expansion, in CaO-CO2-bonded zirconia investments, was about 1.5-2.5%. On the whole, calcium oxide is expected to be a good binder for high temperature dental casting refractory.

Calcium↗
PubMed1989

[Fracture toughness of human enamel].

The fracture toughness (KIC) of human enamel was examined by means of Indentation Microfracture Method (IM method). The IM method was a simple, efficient and economical means to obtain KIC of human enamel. Judging from the relationship between load and crack size, a median crack occurred in the range of 2.45-5.88 N, and KIC was hardly affected by the difference of surface roughness. KIC of a 58-year-old man's teeth was 0.61 MPam1/2 in 1 and 0.77 MPam1/2 in 7 and the difference was significant (P less than 0.01). KIC differed much from the direction of the indenter pressed to enamel rods and the KIC of the direction of enamel rods axis I was markedly higher than that of others. In the 58-year-old man's 1, KIC was 0.61 MPam1/2 in the direction of enamel rods axis V, 0.66 MPam1/2 in the direction of H and 0.84 MPam1/2 in the direction of I, and the difference was significant (P less than 0.01). The values for a 10-year-old man's permanent teeth was slightly higher but showed a similar inclination to the 58-yer-old man's teeth.

Dental Enamel↗
PubMed1988

A nasal allergy model developed in the guinea pig by intranasal application of 2,4-toluene diisocyanate.

An experimental model of nasal allergy has been developed in guinea pigs by intranasal application of 2,4-toluene diisocyanate (TDI). A 10% TDI solution in ethyl acetate was painted onto the nasal vestibuli of the animals once a day for 5-10 days. During the course of repeated application of TDI, the number of animals which secreted rhinorrhea containing eosinophils increased. Morphological survey of the nasal mucosa showed infiltration of eosinophils and some other changes indicative of acute inflammation. Moreover, mast cells were found not only in the subepithelial connective tissue but also in the epithelial layer. Nasal mucus obtained from the mucosa has been found to be an effective test material for studies of nasal allergy. A striking decrease of specific granules was found in some mast cells contained in the mucus. In parallel with the symptomatology, biochemical and serological studies suggested the involvement of type I allergy in the experimental system; TDI-specific histamine release from the nasal mucosa and positive passive cutaneous anaphylaxis were found 3 weeks after the application of TDI.

Administration, Intranasal↗
PubMed1987

Contact sensitivity induced in mice by methylene bisphenyl diisocyanate.

An experimental model of contact sensitivity has been developed in C57BL/6 mice using methylene bisphenyl diisocyanate (MDI), a raw material of polyurethane resins. Sensitization through a single epidermal application of 1% MDI solution in ethyl acetate to the backs of the mice resulted in marked ear swelling. The time course of the swelling was characteristic of delayed-type hypersensitivity and the increment of the ear thickness was compatible with that induced by toluene diisocyanate (TDI). Passive transfer of the MDI-induced contact sensitivity was successfully achieved using lymphocytes from the lymph nodes of MDI-sensitized syngeneic mice, and the effector cells were found to be T cells. Cross reaction between MDI and TDI has shown that MDI is not only a potent contact sensitizer but also can form a contact sensitizer group together with TDI.

Administration, Cutaneous↗