Hajime Ishigami

Promotion of Nickel (Ni) Allergy by Anamnestic Sensitization with a Bacterial Component, Lipopolysaccharide (LPS), in Mice

Background/Objective: Lipopolysaccharides (LPS) promote allergic responses to nickel (Ni) both in the sensitization and elicitation steps. In this study, we examine the effect of pre-sensitization to LPS on the occurrence of Ni allergy using a mouse model. Method: A 100 mg of LPS was injected into C57BL/6J mice intraperitoneally (ip). Three weeks later, the mice were subsequently injected with 0.3 μ moles of nickel dichloride (NiCl2) and 100 μg of CpG-DNA, which acted as an adjuvant. The mice were repeatedly immunized with the 0.3 μg of nickel sulfate (NiSO4), along with 300 μl of the adjuvant, Inject Alum (Pierce, USA). Then we examined the producing capabilities of T helper type 1 (Th1) and 2 (Th2) cytokines (interferon-gamma- (IFN)-γ and interleukin (IL)-10, respectively) from anti CD3 antibody-stimulated spleen cells. Results: Pre-treatment with LPS, followed by repeated challenges with Ni2+ and adjuvants significantly enhanced the IFN-γ-producing capability of spleen cells (n=5, p<0.01); however, that could not enhance the capability of spleen cells by a single challenge with Ni2+ and adjuvants (n=5). In contrast, without LPS treatment, single or even repeated challenges by Ni2+ could not enhance the IFN-γ-producing capability. On the other hand, the IL-10-producing capability of spleen cells was not enhanced even by LPS and repeated challenges with Ni2+ and adjuvants. Conclusion: The solitary pre-sensitization to LPS is essential for the onset of Ni allergy by shifting the Th1/Th2 immune balance toward a Th1 dominant.

Correlation between Chewing Path and Muscle Activity in Chewing Movement. Premature Contact.

This study was performed to determine whether or not malocclusion decreases the interdependent relationship between the chewing path and muscle activity. For experimental premature contact attached to the lower 1st molar on the habitual chewing side, two thicknesses (50 μm and 100μm) of metal foil were used. Chewing movements using a stick of gum were recorded simultaneously as the path and electromyograms. The parameters for the path were the amount of anterior-posterior and right-left movements at 1 mm, 7 mm and lowest point vertically below the intercuspation in the opening-closing path and the maximum amount of mouth opening per stroke, and those for electromyograms were the interval of EMG bursts and the integrated in the central portion of the bilateral masseter muscles and the anterior portion of the bilateral temporal muscles. The presence or absence of premature contact, and changes in the relationship between the chewing path and muscle activity according to the thickness of interference were analyzed in terms of the first canonical correlation coefficient in canonical correlation analysis. Premature contact could be a factor that decreases the first canonical correlation coefficient, but no differences were observed between the two thicknesses.

The Influence of Continuous Mastication with Non-habitual Chewing Side on Masticatory Movements.

The present study was designed to analyze the influence of the continuous mastication with the nonhabitual chewing side on mastication movements.1. The daily increase in the ratio of one side biased chewing on the nonhabitual chewing side was either rapid or gradual.2. On the habitual chewing side, there were no daily characteristic fluctuations in the 2 variables of area, but other parameters tended to increase. On the other hand, on the nonhabitual chewing side, all parameters tended to decrease daily.3. As a result of a canonical correlation analysis made between the number of chewing strokes and all parameters on the habitual and the nonhabitual sides, the first canonical correlation coefficient was larger on the nonhabitual side than on the habitual side.

Tolerance of Left-right Deviations on the Arrangement of the Upper Middle Artificial Teeth

The present study investigated the tolerance of left-right deviations in the arrangement of the upper middle artificial teeth relative to the median line of the face. For this purpose, the alignment of the maxillary incisor relative to the median line of the face was used as a point of reference.The model photos used for this investigation were prepared by combining 5 photos of both the face and the rows of teeth. In a stimulation series, the center of the row of teeth was displaced either to the left or to the right, and magnitude of this displacement was evaluated by groups of dentists, patients and students, who examined these photos. The results were classified into 5 reaction categories. According to magnitude adaptation level and estimation method, the left-right deviation tolerance was determined by psychological judgement.The results revealed that the lowest average tolerance of measuring 2.586mm was reported by the group of dentists, followed by values of 3.704mm and 4.204mm, which were reported by patients and students, respectively.

Estimate of the Original Gingival Color in Reflection Spectrum Data of Redness Gingiva by Multiple Regression Analysis.

This study was made to examine if original gingival color of an individual patient in healthy condition can be presumed from the observed data on the color of his gingiva having presented pericoronal gingival redness. The subjects were 50 males (aged 23-31) whose gingivae have been identified as clinically healthy. X, y, V, Bl and f values were determined from raw data obtained by the color measurement of 4 gingival spots near the cervical regions of maxillary central and lateral incisors. Multiple regression analysis was made with x, y and V values of the healthy papillary gingiva as objective variable and with each element of the observed data (twenty-dimensional observed value vector) upon the manifestation of gingival redness, which has bi-graded according to the degree of redness (slight redness, redness), as explanatory variable.As a result, the analysis of a bi-graded observed data series according to the degree of gingival redness was confirmed to make it possible to presume the original gingival color of the papillary part in healthy condition, suggesting the usefulness for its clinical application.