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Biomedical subjects

A Shiba

Publications and source records attributed to A Shiba.

At least 19 recordsLinked to original sources
PubMed1991

Identity of hemolysins produced by Bacillus thuringiensis and Bacillus cereus.

A hemolysin (Bt-hemolysin) produced by Bacillus thuringiensis var. kurstaki HD-1 producing crystalline toxin(s) was purified by successive treatments of ammonium sulfate (45-65%) and column chromatography using DEAE-cellulose, Sephadex G-75 and KB-002 (a hydroxyapatite column for fast protein liquid chromatography). A hemolysin (Bc-hemolysin) produced by B. cereus HG-6A was also purified by the same procedure. The purified Bt-hemolysin and Bc-hemolysin, both of which are thiol-activated hemolysins, were biologically, physicochemically and immunologically identical. These findings provide further evidence of the similarity of B. thuringiensis, which is being used as a biological insecticide, to B. cereus, a toxigenic organism of food poisoning.

Bacillus cereus↗
PubMed1990

Adhesive bonding of denture base resins to plastic denture teeth.

The adhesive bonding of denture teeth to denture base resins in dentures with conventional acrylic teeth and crosslinked plastic teeth was investigated. The dentures with highly crosslinked plastic teeth such as SR-Orthosit, Crystal ND, and Mitel-OM showed poor bonding at the tooth/base resin interface using the conventional bonding method. Elimination of the alginate mold lining material in the conventional bonding method effectively improved bonding at the tooth/base resin interface. The application of 4-META adhesive bonding agents to the denture teeth improved the interface bonding of highly crosslinked plastic teeth and the denture base. Dentures with Orthosit and Mitel showed differences in bonding ability when two different adhesives were used.

Acrylic Resins↗
PubMed1990

Impact resistance of highly crosslinked plastic denture teeth.

The impact resistance of highly cross-linked plastic denture teeth materials such as SR-Orthosit (R), Crystal-ND (R), and Mitel-OM (R) was investigated and compared to that of conventional denture teeth materials. Dentures with upper second molars were placed on a metal model. The thicknesses of the denture teeth were 1.4, 1.0, and 0.4 mm. An impact force was repeatedly applied to the central fossae of the denture teeth with an impact test machine. Impact resistance was defined as the number of impacts sustained by the tooth material prior to fracture. The results showed that the impact resistance of highly crosslinked plastic teeth decreased with decreasing thickness, but was comparable to that of conventional plastic teeth when the teeth were 1.4 mm thick and supported by denture base resin. It is hypothesized that the layer of PMMA denture base resin beneath the denture teeth functions as a shock absorber during impact.

Dentures↗
PubMed1990

[Analysis of the denture dynamics in R.P.D.'s. 2. Influence of retainers on the dynamics of free-end-saddle].

The ordinary denture movement during function is defined as the "Denture dynamics" in R.P.D.'s. by K. H. Körber (1975). The Author has already reported the evaluating method of the denture dynamics objectively by two ways: The displacement sensors of magnetoresistors detected the vertical and horizontal movements of denture saddle in free end situation. Tiny accerelometer also detected the accerelation during the movements. In this present study, the correlations among the retainers used, the extent of the denture dynamics in displacement and accerelation, the occluding force and the abutment tooth mobility induced by the denture support were correlatively evaluated in two patients with class I free end R.P.D.'s. with interchangeable retainers by above methods. All the data were collected simultaneously by the electronic measuring and recording apparatus. Following results were obtained: 1. The denture dynamics depended on the selection of retainers examined. The extent of the dynamics reduced from the denture with the wrought wire clasps, the denture with the cast clasps, then to the denture with cone crown telescopes in sequence. 2. The occluding force increased just as the changes in sequence of the denture dynamics. 3. The abutment tooth moved to the distal in each case. The highest value of the mobility was found in the denture with the cast clasps, then in the denture with the wrought wire clasps. The least value of the tooth mobility was found in the denture with the cone crown telescopes. These results will strongly support the concept of the free end saddle R.P.D.'s anchored and supported rigidly by the abutments and the residual ridges in clinics.

Dental Abutments↗
PubMed1990

[The evaluation of wear resistance of hybrid denture teeth].

Wear characteristics of hybrid denture teeth, plastic denture teeth which were partially reinforced with metal, was evaluated. The plane specimens were made up with resin and metal. Light curing veneering resin, new metacolor, heat curing veneering resin, Mitel-OM and PMMA (Poly methyl methacrylate) were used for resin parts, while gallium containing filling alloy, silver alloy, palladium alloy and titanium containing chromium cobalt alloy were used for metal parts. The specimens were abraded by the rod specimens of palladium alloy with abrasion test machine. The wear depth and width were measured at 1, 5, 10 and 20 x 10(4) times of abrasion which stroke was 10 mm each. The specimens of heat cured veneering resin reinforced with chromium cobalt alloy showed the least wear loss while the specimens of PMMA reinforced with silver alloy did the most. The difference of wear ratio between light cured and heat cured veneering resin was not statistically significant.

Dental Alloys↗
PubMed1989

[Prosthetic rehabilitation with the removable partial dentures using telescopic crowns after removal of unsuccessful dental implants].

It is well-known that unsuccessful dental implants sometimes give rise to pronounced inflammatory bone resorption of the upper and lower jaw, and that in such cases it is practically much difficult to attain adequate prosthodontic rehabilitation after removal of the implants. On this study it is completely reported that two patients suffering from implant-induced osteomyelitis could be finely compensated for with the removable partial dentures using telescopic crowns after removal of the implants, and then the results are shortly discussed from the view of pathology, oral surgery and prosthodontics. In the first case a 52-year-old woman had been suffering from osteomyelitis of the right mandible due to the both bladevent and endodontic-endosseous implant, and in another case a 43-year-old woman had been suffering from osteomyelitis of the right maxilla due to the endosseous subperiosteal implant, and they had borne insufficient mastication on the affected side of the jaws. Several months after removal of the unsuccessful dental implants, they were rehabilitated with the removable partial dentures using telescopic crowns to recover and maintain good functions such as occlusion, mastication, cosmetics and speech, and oral and general health.

Adult↗
PubMed1988

Re-evaluation of normal human urinary proteins fractionated by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Proteins in normal human urine were clearly fractionated into 26 bands with molecular weights from 14,000 to 230,000 by means of one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with silver staining. The main band contained uromucoid, and the second main band had albumin. However, when urine samples from healthy persons were electrophoresed in the absence of SDS using polyacrylamide gel or agarose gel, or a cellulose acetate membrane, albumin but not uromucoid, frequently formed the main protein band. It is suggested that this is due to the complexing of uromucoid subunits to form a large molecule which cannot penetrate into the gel. In order to correctly fractionate all the proteins contained in normal human urine, it was concluded that it was best to treat a urine sample with SDS with pre-condensation, fractionate it by SDS-PAGE and stain fractionated proteins by a highly sensitive method such as silver staining.

Adult↗