Fibronectin isolated from human plasma was investigated to see if it inhibits the reaction of spontaneous precipitation of amorphous calcium phosphate and hydroxyapatite transformation in higher and lower supersaturated calcium phosphate solutions at pH 7.4 and 37°C. The inhibition was predicted to be caused by binding between fibronectin and calcium ion, and or hydroxyapatite. The results indicate that fibronectin in salivary secretions plays a role in the early stages of the formation of acquired enamel pellicle which is related to the formation of dental plaque

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Formation of the median palatine suture, situated between the right and left horizontal plates of the palatine bones in mice, was studied by light, stereoscopic and scanning electron microscopy.
The anterior one-quarter region of the suture was formed in four steps- cell aggregation, appearance of secondary cartilage, synchondrosis and gradual ossification of the secondary cartilage. The posterior three- quarter region of the suture was formed in two steps- cell aggregation and formation of collagen fiber bundles. Moreover, the former and the latter indicated straight and interdigitated orientation, respectively.
Each region of this suture appeared to have dissimilar extrinsic functions on the basis of the sutural morphology corresponding to the extrinsic functions.

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Ramification aspects of the external carotid artery of the adult rabbit (740 sides) were investigated by means of the acryl plastic injection method. Principal branches of the external carotid were the lingual, the facial and the occipital arteries. Origins of the lingual artery were classified into five types, in reference to other branches of the external carotid as well as the arising features (six types) of the occipital artery. The common carotid artery bifurcated into the external and internal at the height of the middle of the 1st cervical vertebra. The external carotid, in a position lateral to the digastricus and the styloglossus muscles after passing between them, divided into two termini, the maxillary and the superficial temporal at the height of middle of the mandibular ramus, although this position was located more proximal (lower) in about 20%. The lingual and the facial arteries arose independently from the external carotid artery, rarely from the maxillary artery, and via a common trunk (linguofacial trunk) between them. When the facial artery arose from the maxillary artery, the bifurcating height of the common carotid artery was always located more proximally. The occipital artery arose from the vertebral, the internal carotid, the external carotid (as the 1st or 2nd branch), the posterior auricular and the superficial temporal arteries, respectively. When the external carotid was shorter in length since its terminal bifurcation was located more proximally, no branches arose from it.

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Indian skulls possessed by the 1st Departement of Anatomy in the Tohoku Dental University can be divided into five stages on the basis of their stage of tooth eruption.
Growth changes of the palate have been assumed on the basis of the mean values and growth rates of each measured region on the palate. The mutual relation between the lengths of the palatal process of the maxilla and of the horizontal plate of the palatine bone was also examined for every stage.
The length of the palatal region of the premaxilla and the width of the forward region of the palate changed in relation to the eruption of permanent incisors or permanent canines. The length and the width of each region in the 5th stage increased by 1.01 and 1.08 times those of 1st stage. The lengths of palatal process of the maxilla, the bony plate and the alveolar process grew in relation to the eruption of the molar teeth, and the lengths of these three regions in the 5th stage increased by 1.55, 1.39 and 1.42 times those of the 1st stage, respectively. The length and width of the horizontal plate of the palatine bone and the width of the rearward region of the palate grew comparatively smoothly, and the lengths of these three regions in the 5th stage increased by 1.47, 1.23 and 1.26 times those of the 1st stage, respectively.
The results of the measurements revealed that the shape of the palate had a tendency to be long with longitudinal growth. In particular, the growth of the rearward region of the palate appeared to be related to the eruption of the molar teeth.
Furthermore, both lengths of the palatal process of the maxilla and of the horizontal plate of the palatine bone seemed to be related to keep the length of the palate constant on the basis of the negative values of the coefficient of correlation between both these lengths in all stages.

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The purpose of this study was to investigate the histopathological and enzyme histochemical changes in the periodontal tissues in response to occlusal trauma and marginal periodontitis elicited in rat molars. In addition, cases administered with indomethacin which is one of the inhibitors of prostaglandin biosynthesis, were investigated.
The following results were obtained.
1. The occlusal trauma showed osteoclastic resorption, so-called undermining resorption, within the alveolar bone. The marginal periodontitis showed more osteoclastic resorption than in the occlusal trauma, in addition, the infiltration of the neutrophils, the lymphocytes and the existence of the bacteria in the interdental papillae were seen. Because of this fact, it is considered that the inflammatory cell infiltration and the bacterial endotoxin was related to the bone resorption. The forms of the osteoclasts were similar in both diseases.
2. The administration of the indomethacin caused a decrease of the osteoclast in the both diseases, showing morphologically miniaturization of the cell, hyperchromatism by the pyknosis, and the disappearance of the vesicle and the ruffled border. The effect of indomethacin on the osteoclasts was similar in the both diseases.
3. ACP and LDH activity in the osteoclasts which plays an important role in the bone resorption, was decreased by the administration of indomethacin. It is considered that this was caused by the morphologic changes in osteoclasts, and decreased the bone resorption.

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The origin and ramifications of the facial artery of the rat were studied by means of the acryl plastic injection method. The facial artery arose from the anterior wall of the external carotid when it curved laterally at a position between the digastricus and the styloglossus muscles. This artery passed anteroinferiorly between the masseter and the digastricus and gave rise to the ascending palatine artery, the styloglossal, the submandibular glandular and the tonsillar branches. From the submandibular position of the facial artery, the masseteric and the submandibular lymph node branches and the submental artery were derived. The facial then appeared on the face after passing through a notch for the facial vessels. From the facial position of this artery, the posterior cutaneous branch, the inferior labial artery, the oral angular artery, the anterior cutaneous branch, the superficial and the deep posterior superior labial arteries, the superior labial artery and the naris lateral artery were derived in this order. The main stem of the facial terminated into the angular artery. The following masseteric branches were observed; the direct branch from the facial, branches from the oral angular and the deep posterior superior labial arteries, all of which generally supplied the superficial layer and the anterior portion of the deeper layer of the masseter. The cutaneous branches extended their distribution area to branches of the facial nerve and parotid duct. The facial nerve formed a peculiar plexus at a position superolateral to the oral angle, which was supplied by the anterior cutaneous branch and the superficial posterior superior artery.

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The[³H]miborelone ([³H]MI) -binding ability of the androgen receptor (AR) from rat submandibular gland has been studied under acidic conditions. Both in the presence and absence of 10 mM molybdate, the[³H]MI-binding ability was decreased as the pH of the cytosol decreased with the addition of acetic acid and HCl, with pH 5.9 giving 50% binding. This loss of the binding ability was recovered when the acidic precipitate obtained by centrifugation was dissolved in a buffer at pH 7.3. In the presence of molybdate, this recovery of the binding clearly correlated with the protein content of the precipitate. In the absence of molybdate, however, the maximum binding recovered in the precipitate was achieved at pH 4.9, and rapidly decreased at lower pH values (1/2 value obtain-ed at pH 4.1), even though the protein content in the precipitate was still rather high. When the cytosol was first labeled with[³H]MI and then the pH was decreased in the absence of molybdate, [³H]MI-AR complexes remained unchanged until reaching pH 5 and the amount was then decreased, with pH 4.2 giving 50% binding. These results indicate that both unoccupied and liganded AR denatures irreversibly at pH 4.1-4.2. On the other hand, in the presence of molybdate, [³H] MI-AR complexes were more resistent under acidic conditions and a considerable amount of the complexes could still be observed until pH 3. In addition, under acidic conditions in the presence of 0.5 M KCl, AR was transformed to a state which could bind to DNA-cellulose. In conclusion, AR from rat submandibular gland exists in a specific state between pH 4.1-5.9; AR at this state has no ligand-binding ability, but once formed, [³H]MI-AR complexes do not dissociate. At lower pH values, AR is transformed, and subsequently denatures. Moreover, similar results were obtained from AR from rat prostate, glucocorticoid receptor from rat liver, and estrogen receptor from rat uterus, indicating that these are the common characteristics among these receptors.

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Thirty-eight cases of the oral papilloma were examined for the presence of papillomavirus antigen by the peroxidase-antiperoxidase (PAP) method.
The antigen could be detected in two oral papillomas. The PAP stains in these papillomas were localized in the nuclei of koilocytotic cells on the surface layer of the stratified squamous epithelium.

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An extracellular sucrase from Actinomyces viscosus ATCC 19246 was partially purified about 2, 900-fold with a yield of 10%. The molecular weight of the enzyme was estimated to be approximately 48, 000 by Sephadex G-150 gel filtration. Km value of the enzyme for sucrose was 18 mM. The activity was optimally reactive at pH 6.0 and at 50°C, and was markedly inhibited by FeCl₃, ZnCl₂, and HgCl₂. The enzyme was specific for sucrose and produced equimolar glucose and fructose. Moreover, it degraded raffinose, but not melezitose, levan, inulin, and dextran. These results indicate that the enzyme is an invertase.

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A protein fraction strongly adsorbed to hydroxyapatite crystals was isolated from Lingula unguis shell. It is an acidic protein complex with a molecular mass of 140 kDa, and abundant in asparatic acid, glutamic acid and glycine. Amino acid analysis indicated an unidentified ninhydrin positive acidic component, but not γ-carboxyglutamic acid. The amino acid composition is similar to that of osteonectin and bone morphogenetic protein. The protein having an affinity for calcium contained somewhat large fractions of an α-helical structure and a β-structure. The conformation did not change by increasing calcium concentration. The protein fraction was a multi-components complex build up by hydrophobic and disulfied bonds.

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The beige mouse is an animal with the homologue of Chediak-Higashi syndrome, which is an autosomal recessive trait and is characterized by the susceptibility to infection. The periodontal tissues from ten male 4-week-old beige (bg/bg) and five male non-beige (bg/+) mice were investigated ultrastructurally to elucidate the condition of the junctional epithelium (JE) of the gingivae of young beige mice. In both types of mice, PMNs were present in the intercellular spaces of the coronal site JE, but in the apical site. Vacuoles were frequently found in the cytoplasm of the JE cells in the coronal site, but not in the apical site. Lipid-like droplets were found in JE cells in both types of mice but giant granules were seen in JE cells in beige mice. It is suggested that the presence of giant granules in JE cells are characteristic of beige mice.

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The sn-1 position of phosphatidylcholine from rat sublingual gland was highly occupied by saturated fatty acids, palmitate and stearate. Arachidonate and linoleate were exclusively located at the sn-2 position. Such asymmetry was also observed in phosphatidylethanolamine, although considerable amounts of alkenyl moieties were present at the sn-1 position. Based on their contents, it was suggested that the most abundant molecular species of phosphatidylcholine and phosphatidylethanolamine are 1-palmitoyl-2-arachidonoyl and 1-stearoyl-or 1-alkenyl-2-arachidonoyl (plasmalogen) types, respectively. Chronic administration of isoproterenol which causes an increase of linoleoyl-phospholipids in parotid and submandibular glands did not affect the positional distribution of fatty acids in phosphatidylcholine and phosphatidylethanolamine from the sublingual gland.

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