The ultrastructural localization of the elastic fiber system was examined in fibrous zone of mandibular condyle in the mice at 1, 2 and 4 weeks of the age. Sparce fibrillar components were observed at 1 week, among fibroblasts. At 2 weeks, thick collagen bundles appeared and ran in various directions. The collagen bundles formed layers at 4 weeks and the layers of collagen fibers were at right angles to one another. The elastic fiber system was localized in the area where collagen fiber bundles crossed each other. The ultrastructure of elastic fiber system varied along with maturation of the condyle. Many oxytalan or elaunin fibersappeared at 1 or 2 weeks, but the mature elastic fiber system was observed at 4 weeks. The stress on mastication contributed to the growth of the elastic fiber system.

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The sexual dimorphism of mesio-distal and bucco-lingual diameters from the central incisor to the first molar in the Yami tribe of Taiwan aborigine was described, and three discriminant function analyses based on these diameters were carried out. The actual percentage of correct discrimination indicated 67.65% from the 12 mesio-distal diameters, 73.53% from the 12 bucco-lingual diameters, and 85.29% from the 24 diameters combined of mesio-distal and bucco-lingual diameters. The highest percentage from the 24 combined tooth diameters reached to the average percentage obtained from the cranial diameters. Although the sex discrimination rate obtained using tooth measurements has been regarded lower than that using postcranial or cranial bones, the results we obtained demonstrated the usefulness of the tooth diameters in this analysis. When either of mesio-distal or bucco-lingual diameter is available in actual use, bucco-lingual diameters are recommended to be used, because they are not affected by interproximal wear and showeda higher percentage of correct discrimination.

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Periapical bone destruction is an important pathogenic sequellum of pulpal infecti on, and interleukin1 (IL-1) and tumor necrosis factor (TNF) have been implicated in the pathogenesis of apical periodontitis. The relationship between the bone destruction and appearance of osteoclasts were investigated in developing ratperiapical lesions. Furthermore, bone resorptive cytokines (IL-1α, TNF α) produced by osteoclasts were analyzed. Osteoclasts appeared beginning on day 2 and increased on day 7. The kinetics of bone destruction was almost in parallel to the appearance of osteoclast after pulp exposure. IL-lα and TNFα were both detected on the osteoclasts. By contrast, production of IL-1β and TNFβ was not found by immunohistochemical techniques and in situ hybridization. These findings demonstrate that IL-lα and TNFα are produced from osteoclast in developing periapical lesions of rat, and these mediators play keyroles in periapical destruction.

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The present study investigated changes in histological features and nuclear organizer regions (NORs) in the junctional and pocket epithelia of an experimental model of periodontitis in adult dogs were examined. In one group (the ligature group), a silk ligature was placed below the gingival margin for 1, 3, or 6 months. In the other group (the removal group), the dogs were followed up for 1, 3, or 6 months after removing the silk ligature, which had been applied for 6 months.
The results were as follows: 1. Histopathologically, both groups showed destruction and repair of the epithelium in marginal periodontitis. 2. On the basis of the silver staining of NORs (AgNORs), the mean number of AgNORs per nucleus (AgNORs number) of junctional and pocket epithelial cells in the control and experimental groups was in the range of 1.21-2.73. The mean AgNORs number increased with time in the ligature groups and decreased in the removal groups. The number of AgNORs per epithelial cell ranged from 0 to 5. In the control group, there was a larger number of AgNORs, clustered in the basal cell layer and apical junctional epithelium. During destruction of the epithelium in the ligature groups, AgNORs increased in all layers and showed a scattered distribution. During therepair of the epithelium in the removal groups, there initially was a reduced number of AgNORs in the basal layer. Subsequently, the mean AgNORs number approximated that in the control group.
The changes in the AgNORs number and distribution in junctional and pocket epithelia appear to be useful as indicators of destruction and repair of the epithelium in marginal periodontitis.

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The effect of retinoic acid on morphogenesis of the oral cavity including tooth germs was examined. Retinoic acid solutions, prepared at the concentrations of 50, 5 and 0.5μg/g weight, were injected from one to 3 times into the abdominal cavity of 7-to 14-day pregnant mice. The head and neck regions of the embryos in various developmental stages were cut into serial sections and processed for examination under the light microscope. Following the microscopic observation, sections were read into a computer for three-dimensional analysis. Moreover, afterthe administration of BrdU, some of the samples were immunostained with anti-BrdU serum to survey the distribution of the cells at the DNA-synthesis stage.
With administration of 5 or 50μg/g weight on day 7 to 10 of pregnancy, excencephalia, lip cleft, fusion of incisor germs and small mouth were observed in highfrequencies. Cleft palate also arose in high frequencies by administration on days 10 to 14 of pregnancy, in addition to that on days 7 to 10 of pregnancy.
Computer graphics showed that retinoic acid gives rise to the dwarfed enamel organ and the molar tooth germs in the mesial side more than usual.
BrdU immunostaining revealed that the BrdU positive cells decrease in number in the enamel organ and the epithelium of the palate of the embryos from the retinoic acid-administrated groups, which received 5μg/g weight on 7 th, 8 th and 10 th days of pregnancy.
These findings suggest that an excessive intake of retinoic acid during pregnancy brings about an inhibitory action on morphogenesis of the tooth germs and palate and that the degree and type of abnormal-ities are dependent on the amount and time of retinoic acid administration.

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To elucidate the effects of food consistency on chewing patterns, the electromyographic (EMG) activity of the masticatory muscles (masseter, digastric and mylohyoid) and jaw movement orbits were recorded in freely moving rabbits during chewing two foods with a different texture (bread and uncooked rice). When the hard food was tested, the burst duration of the masseter increased on both sides, but no significant differences in the burst duration were observed in either the digastric or mylohyoid muscles. The burst timings varied between the bread and rice chewings, especially in the offset time of bilateral masseter bursts and the onset time of mylohyoid bursts. The amplitudes of masseter and mylohyoid on both sides were obviously affected by food texture. Although the cycle time and fast closing time were consistent between the foods, the slow closing time during hard food chewing was significantly longer than that during soft food chewing. The results indicated that food consistency greatly influenced both amplitude andburst duration in the closer activities, but influenced neither amplitude nor burst duration in the digastric muscle as a primary jaw opener. In the case of mylohyoid muscle, the food texture affected the amplitude alone. This suggests an additional role of the muscle in tongue manipulations to that as a jaw opener.

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Aqua-oxidized water (AOW) which is produced by electro-disintegration of 10-20% NaCl solution, is a bactericidal agent. The bactericidal activity is attributed to Cl₂, HOCl, superoxide anion, and acidification (pH2.3), but have not been clarified. Herein, the cytotoxicity of AOW was tested by flow cytometric assay, colony formation, and MTT assay with L929 cell lines stemmed from subcutaneous tissue in C3H mice. The flow cytometric assay was performed using the fluorescein diacetate (FDA)-propidium iodide (PI) double staining technique followed by the trypan blue exclusion test. After FDA-PI staining, the cells were analyzed by FACStar plus and LYSIS II software. The colony formation test and MTT assay were performed using the usual methods. Cytotoxicity (LD50) determined by (1) Flow cytometry was 25W/W%(non-serum), and 43W/W%(10% serum), that by (2) colony formation was 25W/W%, and that by (3) MTT assay was 20W/W%, The cytotoxic effect of AOW remained active even in the presence of a high percentage of 5-20% serum. These findings suggest that AOW is cytotoxic to fibroblasts and the application of AOW to humans should be confined to the external area of the body.

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The three-dimensional ultrastructure of connective tissue fibers at the muscle -tendon junction of the rabbit tongue muscle, which was treated by NaOH solution, was observed by scanning electron microscopy. Muscle fibers of the transverse and vertical muscles of the tongue were covered with a network of endomysial fibers and perimysial fibers consisting of collagen fiber bundles running in the direction of the long axis of the muscle fiber. The perimysial fibers ran in a slightly spiral manner, and densely surrounded the area at the ends of the muscle fibers. There were sporadical impressions of muscle fiber ends entering the lingual aponeurosis, and these impressions were partitioned by endomysial fibers to form small impressions. The small impressions were revealed to eventually form micro-impressions of about 0.35μm in diameter. The diameter is larger than that of the digitate process known by transmission electron microscopy, probably because the thick basement membrane around the digitate process has been digested.

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The distribution of the sensory units innervating the upper face was analyzed incats anesthetized with sodium pentobarbital. The infraorbital nerve trunk innervating the upper face was composed of several nerve fascicles at the orbit. The receptive field of each fascicle was defined by recording the nerve action potentials responding to the mechanical stimulation of the facial area. The cross sectional area of each fascicle and the size of its corresponding receptive field were measured by the image analyzing method. The value calculated by dividing the former by the latter was adopted to compare the relative density of the sensory units among various facial areas. The relative density in the apex of the nose and the upper lip was larger than that in the dorsum of the nose and the area below the eyelid. This suggests that the sensory units were more densely distributed in the apex of the nose and the upper lip. The size of the receptive field of each sensory unit was measured by means of the single unit recording responding to the mechanical stimulation of the facial area. Sensory units innervating the apex of the nose and the upper lip had smaller receptive fields than those in the other areas. A significant correlation was recognized between the size of the receptive field and the density of the sensory units. These findings support theprevious findings in man that the frontal part of the face is more sensitive than the other part of the upper face.

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The collagen movement in the matrix of mandibular cartilage of rats from 0 to 70days old was examined, using the polyclonal antibody for type I, II and X collagen.
Thus, the immunoreaction for type II collagen antibody was found in the extracellular matrix of the maturative and hypertrophic cell layers. The intensity of the reaction decreased in the hypertrophic cell layer with growth, but, inthe maturative cell layer, was found continuously. The immunoreaction for type Icollagen antibody was found in the extracellular matrix in all layers of the mandibular cartilage. The intensity of the reaction in the maturative and hypertrophic cell layers was stronger than that of the fibrous and proliferative cell layers and decreased in the latter layers with growth. The immunoreaction for type X collagen antibody was found in the extracellular matrix of the hypertrophic cell layer. The intensity of the reaction was found to be stable in rats 0 to 40 days old, but, 40 days or older the type X collagen reaction decreased.
In conclusion, the collagen in the rat mandibular cartilage is localized in the extracellular matrix of the particular cell layer that plays a role for each component, and is thought to be an expression of the functions in the temporomandibular joint and thought to be concerned in the ossification of growth.

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A study was made concerning suppression of mitogenic activity of He²⁺ in lymphocyte proliferation test (LPT). Three kinds of antigens, i. e. Hg²⁺, epidermal protein bound Hg²⁺ and fractionated epidermal protein bound Hg²⁺ was prepared, and the proliferative activity between sensitized lymphocytes and non-sensitized lymphocytes was examined. There was no significant difference in the proliferative response to Hg²⁺ antigen between sensitized lymphocytes andnon -sensitized lymphocytes.
The proliferative response of sensitized lymphocytes to epidermal protein bound Hg²⁺ antigen was significantly increased than the non-sensitized lymphocytes' response or the response in control cultures in RPMI 1640 alone.
The proliferative responses of sensitized lymphocytes to four kinds of fractionated e pidermal proteinb ound Hg²⁺ antigens were specifically increased, while, a slight fluctuation among antigens was observed.
These findings suggested that the influences of the mitogenic activity of Hg²⁺ could be avoided by using the isogenic protein bound Hg²⁺ antigen in LPT.

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Keratin filaments in rat salivary glands were studied by immunocytochemistry using several kinds of antikeratin antibodies and by electron microscopy, to examine the relationship between the keratin subtype and distribution pattern of keratin filaments.
In the parotid, submandibular, sublingual and von Ebner glands, acinar secretory cells, intercalated ducts, striated ducts, and luminal cells of the excretory ducts were stained by PKK1 antibody, which reacts with40, 45, 52.5KD keratin subunits, but not by PKK2, which reacts with 40, 46, 48, 54KD subunits.
These cells contained loosely aggregated bundles of keratin filaments or complicated reticulated filaments. On the other hand, basal cells of the excretory ducts and myoepithelial cells reacted with the PKK2 antibody, but not with PKK1, and contained densely aggregated bundles of keratin filaments. These findings suggest that the aggregation and distribution pattern of keratin filaments reflect differences in the keratin subtypes that comprise these filaments.

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IL-I and TNF are bone resorptive cytokines whichare key elements in th e proinflammatory cytokine cascade that is activated in response to infection. Here, we determined the production of IL-lα, IL-1β and TNFα, TNFβ from mouse osteoclasts in the coculture system. The production of cytokine from osteoclasts was examined by immunohistochemistry and in situ hybridization. In the coculture system of C57BL/6N mouse bone marrow cells and MC3T3-G2/PA6 cells, the colony of osteoclasts were formed after 7 days of culture and IL-la and TNFa were detected in the osteoclast. However IL-β and TNFβ were not detected. In the MC3T3-G2/PA6, these cytokines were not detected. These findings suggested that local production of IL-lα and TNFα by osteoclasts may be an important mechanism for regulating the bone resorption.

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The accuracy in the perception of two-point distance was tested on the tongue, the thumb and the face. We analyzed the difference in stimuli applied in different directi ons. The subject first memorized the distance between two pointers of an esthesiometer which was applied to the mucosa or skin, and then expressed his perceived distance with the caliper held by hand so that the intertip distance was equal to the memorized distance visually. 1) On the tongue the perception of distances in the longitudinal direction was accurate whereas small distances were overestimated and large distances underestim ated when applied in a transverse direction. 2) On the thumb, distances in a longitudinal direction were overestim ated and di stances in a transverse direction underestimated. 3) On the face no directional differences could be detected. These findings revealed the presence of specificity of orientation in the perception of distances on the tongue and the thumb, but not on the face.

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I examined the distribution of cholinergic neuron terminals in the rat submandibular gland. Immunohistochemical procedures with a monoclonal antibody against choline acetyltransferase (ChAT) were used to determine the ultrastructural features of the putatively cholinergic axons. Either the streptavidin biotin-peroxidase complex method or the post-embedding staining with protein A-colloidal gold method was used for immuno-staining. The reaction was too weak to detect using conventional methods for ChAT. Interleukin 3 (IL-3) was used to enhance immunohisto-staining of peripheral cholinergic axons. Good results were obtained with IL-3 treatment. The submandibular ganglions and nerve bundles were both close to the main duct, and both were immuno-reactive to ChAT.
Although a number of ChAT positive fibers were seen within the acini and intercalated ducts of the submandibular parenchyma, they were not in other duct cells. ChAT positive terminals of adrenergic axons were detected by prior treatment with 5-hydroxydopamine (5-OHDA). Axons containing vesicles, not only aminergic but also occasionally cholinergic, were found adjacent to the endothelial cells of blood vessels. Although axons containing dense cores in their vesicles were noted at the basement membrane of acinar and duct cells, ChAT positive terminals were seen in both acinar and intercalated duct cells.
These findings suggest that immunocytochemical staining using ChAT monoclonal antibodies with IL-3 treatment is a useful technique for detection of cholinergic peripheral nerve fibers in the submandibular gland.

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