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The purpose of the study was to determine whether adding calcium lactate to chewing gum containing xylitol enhances remineralization of enamel surfaces using an early caries lesion model. Enamel slabs were cut from human extracted sound teeth and artificial subsurface lesions created within each. Half the enamel slabs were used as controls and stored in a humidifier while half were mounted into oral appliances worn by 10 volunteers (22–27 years old, 2 males and 8 females) in a three-leg trial, during which they wore the appliance without chewing gum, chewed gum containing xylitol + calcium lactate or chewed gum containing only xylitol 4 times a day for 2 weeks. Calcium concentrations in the enamel surfaces of control and test slabs were measured by X-ray spectrometry and degrees of remineralization were calculated. The mean degree of remineralization was greater after chewing xylitol-Ca gum (0.46 ± 0.10) than after no gum (0.16 ± 0.14) or after chewing xylitol gum (0.33 ± 0.10) (p < 0.01). In conclusion, chewing gum containing xylitol + calcium lactate could enhance remineralization of enamel surface compared to chewing gum containing only xylitol or no gum chewing.

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In myotome muscle fibers composing the trunk of the lamprey (Lamperrajapomba), parietal muscle fibers and central muscle fibers, which are histochemically and functionally different from each other, formed single compartments which then formed multiple units. Parietal muscle fibers arranged like a chain in the lateralis, were histochemically identified as red muscle fibers, and classified as slow contracting fibers (Type 1). In contrast, central muscle fibers were present in the medialis surrounded by parietal muscle fibers and histochemically were fast contracting white muscle fibers (Type 2). These observations of the architecture of muscle fibers and muscle fiber types suggest that red muscle fibers (parietal muscle fibers) forming the lateralis of the lamprey are involved in trunk architecture because of their continuous tonic contraction, and white muscle fibers (central muscle fibers) located in the medialis function act as a propelling force used in swimming.

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Using peripheral quantitative computed tomography, (pQCT XCT540, Norland Stratec Co.Ltd.), we quantitatively investigated the age changes of cross-sectional shape of left distal radius (4% of forearm length) inChimpanzees and Japanese Macaques. We devised the Roughness index to quantify the contour shape, that is, standard deviation of radius (from center of gravity of contour). We also analyzed the age change of body weight and other bone parameters (Total Area of the cross-section, Cortical Area and Cortical Density). The results obtaind are as follows: 1) There are three types in patterns of age change. First is the patterns of body weight, Total Area of the cross-section and Cortical Area, which are composed of rapid increase growth and flat adult phases. Second is that of Cortical Density, composed of rapid increase and slow increase phase. Third is that of the Roughness index, increasing linealy with age without significant change of pace. 2) The noticeable differences between the two species are observed in growth span, Cortical Density in adulthood and the intercept of the regression of Roughness Index against age which relates to the fact that the shapes of cross-section is square in Chimpanzees and triangle in Japanese Macaques. 3) The increase in Roughness index and Cortical Density in adulthood indicates remodeling process continues after growth, i.e.,redistribution of bone materials among Cortical parts. By the remodeling, the strengh of bone may be increaced in a specific direction (medio-laterally). The difference of the cross-sectional shapes in the two species appears to reflect the difference in th direction of the secondary mechanical stress in distal forearm.

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