Enhanced expression of several kinds of protooncogene and mutation of tumor suppressor genes have been reported in clinical materials of carcinomas.
These genomic changes chould be a cause of tumorgenesis, progression, invasion, and metastasis of tumoms. In clinical cases, amplification or overexpression of c-erbB-2 proto-oncogene was reported in some carcinomas derived from glandural tissus including salivary glands. There are no repoets concerning oncogene expression during experimantal carcinogenesis in salivary glands. The purpose of this study was to elucidate c-erbB-2 oncogene expression during rat submandibular gland (SMG) carcinogenesis induced by DMBA/sponge implantation using immunohistochemistry and RT-PCR.
The c-erbB-2 oncoprotein was detected in some ductal segment in normal rat SMG. Three weeks after DMBA/sponge implantation, sometimes proliferating duct-like structures were positive for c-erbB-2 oncoprotein. Six weeks later, squamous metaplastic premalignant lesion like a leukoplakia was usually found. Twelve weeks later squamous cell carcinoma was found lin all experimental cases. The c-erbB-2 oncoprotein was strongly positive in most of the tumor cells.
Overexpression of c-erbB-2 mRNA was observed in 60 % at 6 weeks (6 of 10 cases) and in all at 12 weeks.
These results clearly demonstrated that overexpression of c-erbB-2 oncogene product was observed in premalignant lesion and tumor cells. It may suggest that over-expression of c-erbB-2 oncogene product could be related to tumorgenesis and progression in rat SMG carcinogenesis.

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To elucidate the unsolved pathogenesis of oral lichen planus (OLP), the effects of heat, lipopolysaccharide (LPS) and a heat shock protein (HSP) peptide on cytokine production by keratinocytes (KC) and the effects of culture supernatants of KC on transendothelial cell migration of peripheral blood mononuclear cells (PBMC) obtained from healthy individuals were investigated. In addition, the expression of adhesion molecules on KC and human umbilical vein endothelial cells (HUVEC) with the influence of supernatants of KC on the adhesion molecule expression and its associated intracellular signal transduction were studied. Compared to KC separated from the intact gingivae (Nor-KC), KC from oral mucosae with OLP (OLP-KC) produced larger amounts of interleukin-6 (IL-6), granulocytemacrophage colony stimulating factor (GM-CSF), and tumor necrosis factor-α(TNF-α). LPS dosedependently enhanced generation of these cytokines, but the HSP peptide strongly increased TNF-α production by KC. By culturing of PBMC and HUVEC in medium containing culture supernatants of KC, especially those of OLP-KC, the expression of CD11a, CD11b, CD18, and CD49d on PBMC as well as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin on HUVEC were increased. When PBMC were cultured in culture supernatants of KC, migration of PBMC across monolayered HUVEC were increased. The migration upregulatory effects of culture supernatants, which was stronger in OLP-KC than in Nor-KC, were largely decreased by pretreatment of the culture supernatants with antibodies (Abs) to interleukin-1β(IL-1 β), GM-CSF and TNF-α. Further, the migration activity of PBMC was reduced to about 50 % of the control level by pretreatment of PBMC with anti-CD11a or and-CD18 Ab and reduced to about 70 % by pretreatment of HUVEC with anti-CD54 Ab. Furthermore, the migration activity was almost inhibited by pretreatment of PBMC with genistein (tyrosine kinase inhibitor), H-7 (protein kinase C inhibitor), Wortmannin (phosphatidyl-inositol-3; PI-3 kinase inhibitor), Exoenzyme C3 (Rho protein inhibitor), or TMB-8 (Ca⁺⁺mobilization inhibitor). Being compatible with these results, culture supernatants of OLP-KC more upregulated tyrosine phosphorylation of 52, 70, and 102 kDa proteins, PI-3 kinase and protein kinase C activities and active Rho protein level than those of Nor-KC. These results suggested that cytokine generation by KC is enhanced by extrinsic stimulants such as LPS and heat and that cytokines (IL-1, IL-6, TNF-α, and GM-CSF) produced by KC upregulate the expression of integrin family (CD11a, CD18, and CD49d), immunoglobulin family (ICAM-1 and VCAM-1) and E-selectin on PBMC and HUVEC, which results in an increase of migration activity of PBMC via upregulation of intracellular signal transduction.

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It has been reported that the granular convoluted tubule (GCT) is a characteristic structure in the rodent submandibular gland. The GCT segment consists of 3 types of cells, granular, pillar and transition cells. The granular cells are characterized by existence of many secretory granules which contain biologically active peptides (i. e., epidermal growth factor, nerve growth factor). Endothelin (ET) is one of the potent vasoconstrictures consisting of 21 aminoacids. This polypeptide plays an important role in the regulation of vascular smooth muscle tonus. ET was firstly isolated from the endothelium, and is now divided into 3 subclasses as ET-1, 2, 3. ET concentration has been reported compartively high, in the lungs and submandibular gland (SMG), though histochemical distribution of ET has not been demonstrated in tissues and organs. The purpose of this study was to investigate distribution of rat SMG and ET concentration in plasma, saliva, and salivary glands with RIA technique. The results showed that ET-3 appeared in GCT cells of rat SMG. (In ontogenesis, ET-3 appears and increases depending upon growth of GCT cells in postnatal stages. Testostrerone administrated rat showed higher concentration of ET in saliva and salivary glands.), ET-3 may be stored in the granular cells and secreted into saliva. It was suggested that ET-3 is produced and stored in the granular cells of GCT of SMGs, and biological roles for ET-3 differ from those of ET-1 in the blood.

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The method of attaching the jaw to the brainstem preparation in vitro was developed. Recently, the rhythmical trigeminal activities were analyzed using the brainstem block preparation in vitro. By this method, there was no need to worry about the animal condition during the experiment. Our previous paper showed how useful the brainstem block preparation for analysis of trigeminal networks is. However, this preparation cannot show jaw movement.
In this paper, the new method to realize muscle activities with jaw movements is described.
1. Jaw and jaw muscles are attached to the brainstem block preparation.
2. Rhythmical jaw movements are enhanced with chemical stimulation.
3. These movements can be recognized with a CCD camera.

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Parathyroid hormone-related protein (PTHrP) indirectly stimulates osteoclastic bone resorption through osteoblasts in humoral hypercalcemia of malignancy. We reported that the serum concentration of PTHrP elevated in terminal stage patients with oral squamous cell carcinoma (SCC) in 1996. Therefore, PTHrP is a candidate for direct bone resorption factor released from the tumor tissue. The purpose of this study was to elucidate the correlation between the direct bone invasion by oral SCC and PTHrP expression. The serum C-PTHrP concentration was measured in 53 patients with oral SCC. The immunohistochemical study using PTHrP (labeled streptoavidin-biotin method, 38-64 monoclonal and 1-34 polyclonal antibody) was performed in 53 biopsy specimens. The bone invasion was assessed by using panoramic radiographs and bone scintigrams (⁹⁹m Tc-MDP). The mean serum C-PTHrP concentration in the bone invasion identified group was 43.1±17.2pmol/l. In the non-bone invasion group it was 42.0±18.0 pmol/l. No significant correlation was found between serum C-PTHrP levels and bone invasion or between PTHrP (1-34) and (38-64) expression in tumors and bone invasion. These results showed that there is no relationship between PTHrP expression in the biopsy specimen and direct bone invasion.
Since the expression of PTHrP in the tumor tissue attached to the bone of surgical specimens has not been investigated, it is still unclear if PTHrP plays a role in direct bone resorption by oral SCC.

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In this study, the effects of basic fibroblast growth factor on normal rat salivary gland cells were demonstrated. Various concentrations of bFGF (1 to 1, 000 ng/ml) were added to the culture medium, and the results were as follows:
1) bFGF accerelated the cell proliferation at the concentration of 100 ng/ml or more.
2) Short (1 hour) and long (12 hours) contact time with bFGF showed similar proliferative effects on cultured salivary gland cells, suggesting a short reacting time of bFGF.
These results clarified the proliferative effect of bFGF on normal rat salivary gland cells in vitro.

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The purpose of this study was to compare the electromyographs (EMGs) of isotonic and isometric contraction of jaw closing muscles in patients with mandibular prognathism in order to investigate the influence of occlusion on muscle activity.
The integration of EMG activity and Median Power Frequency (MPF) in temporal and masseter muscles was analyzed in the two stages of the phasic tooth tapping movement between the P and C groups.
Stage one was isotonic contraction, just before tooth contact (38 msec.), and stage two was isometric contraction, just after the silent period (38 msec.). The P group included 5 males with mandibular prognathism, and the C group included 5 males without this anomaly.
The results were as follows:
1. In the P group, integration of EMG activities in both isotonic and isometric contractions were significantly lower than in the C group. In integration of EMG activities, the C group had increased isometric contraction compared with isotonic contraction. However, no significant difference was found in the P group.
2. In the P group, MPF in both isotonic and isometric contractions were significantly lower in temporal muscles, but significantly higher in masseter muscles compared with the C group. There was no significant difference between isotonic and isometric contractions in the P and C groups.
These results suggested that integrations of isotonic and isometric EMG activities are influenced by longterm malocclusion in patients with mandibular prognathism. However, these MPF activities are not especially influenced.

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To analyze the features of postomaxillectomy speech disorder and its improvement by means of a prosthesis, the speech intelligibility in 54 patients was measured with and without a prosthesis and assessed according to the manner and place of articulation. The results were as follows:
1. In the manner of ariculation, plosives and of fricatives were misunderstood more often than others expect Group I a without a prosthesis. Especially, this tendency was marked in Group I c, Group II b, and Group II c with a high grade of an oronasal communication. With a prosthesis, all sounds in Group I that had no soft palate resected were understood over 80 % of the time, while in Group II that underwent soft palate resection, flaps and plosives were often misunderstood.
2. At the place of articulation, all sounds except glottal sound were markedly misunderstood except Group I a without a prosthesis, especially linguopalatal sound. With a prosthesis, all sounds in Group I were understood over 80% of the time, while in Group II bilabial and linguopalatal sounds were often misunderstood compared to other sounds.
3. An analysis of transcribed manners of misunderstood plosives and flaps revealed that the post-prosthesis low speech intelligibility scores in patients with a deep defect extending to the intratemporal fossa or with velopharyngeal incompetence of Group II were due to poor oronasal separation and that the oronasal separation was poorer in the latter patients than in the former.

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Extension of the mandibular elevators and contraction of the mandibular depressors during mouth opening were cephalometrically measured.
The temporalis muscle was extended in proportion to wide mouth opening. The masseter muscle was extended at the initial stage of mouth opening but not at later stages. The lateral pterygoid muscle, anterior belly of the digastric muscle and so-called infrahyoid muscle group were contracted in proportion to wide mouth opening. Posterior belly of the digastric muscle was extended during opening movement in females and not contracted in males. In the opening movement of the mandible, the mode of masseter extension differed from that of temporalis extension, and diverse change of length of the muscle was found between the anterior belly and posterior belly of the digastric muscle.

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Papillary hyperplasia often arises in the mucosa of the tongue, palate, lip, cheek, and gingiva but very rarely in the uvula. This paper describes a case of papillary hyperplasia arising in the tip of the uvula. A 59-year-old male was referred to our clinic complaining of a mass in the tip of the uvula. It was discovered by the patient ten years earlier. A 13mm diameter tumor resembling a pedunculated polyp was found in his uvula. Upon the clinical diagnosis of benign tumor, it was removed under local anesthesia. The lesion was diagnosed as papillary hyperplasia. Human papillomavirus (HPV)-DNA were examined using a molecular biological method. HPV-DNA was present, but the type of HPV could not be determined. There has been no clinical evidence of recurrence for four years.

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Temporal arteritis, also referred to as giant cell arteritis, is a rare disease in Japan. The major symptoms are headache, redness and swelling of the temporal artery, and visual impairment. However, since not only the temporal artery but also other arteries are sometimes involved, the clinical symptoms vary.
An 82-year-old female with temporal arteritis, having pain in the temporal region and toothache, was reported. After steroid administration, these symptoms markedly improved, and no recurrence was observed.

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Hospital charts of 253 patients treated for maxillofacial fractures from 1978 to 1993 were reviewed to survey incidence of concomitant injuries associated with maxillofacial fractures.
There were 92 cases of concomitant injuries with an incidence rate of 36.4%. Orthopedic injuries, followed by neurologic, head, abdominal, or thoracic injuries, were the most frequently encountered concomitant injuries.
As to the closed head injuries, the incidence of the loss of consciousness was 38.3 % and 18 patients (7.1%) suffered very severe head injuries. Falls, followed closely by traffic accidents, were the most frequent causes of closed head injuries. The patients with multiple maxillofacial fractures often had closed head injuries. However, it was noted that nearly a half of the patients with only mandibular fracture experienced a concomitant loss of consciousness or a very severe head injury.

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A case of odontogenic myxofibroma occuring from anterior teeth to premolar area of the mandible is reported.
A-24-year old female was referred to our clinic because of a gingival swelling in the right mandibular region in May 1997. A radiograph showed a multiocular radiolucent lesion described as a “soap bubble”. Surgical excision and curettage of the lesion were performed under general anesthesia. Histopathological examination revealed myxomatous tissue with epithelial islands suspected to be odontogenic, and the diagnosis was odontogenic myxofibroma.
Recurrence was not found a year after surgery.

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The desmoplastic ameloblastoma (DA) is classified as a histological variation of ameloblastoma according to the WHO classification of odontogenic tumors in 1992. Generally, this tumor grows in size gradually and a long time elapses before the patient visits a clinic because of lack of pain even if the patient is aware of swelling of the jaw. There are few reports on elderly patients with DA. In this report, a relatively elderly patient with DA of the mandible was presented.
A 70-year-old male was referred to our clinic complaining of swelling of the mandible. At the first visit, there was a swelling with clear border on the mandibular gingiva which was bony hard and partially elastic soft upon palpation. Computarized tomographic findings revealed a honey comb - like structure in almost all of the lesion. Resection of the mandible and reconstruction with iliac bone graft were performed. Histopathological examination revealed some small nests of odontogenic epithelium in the extensively collagenized stroma. Recurrence was not found three years after surgery.

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A case of huge epulis that caused facial deformity was reported. The patient was a 54-year-old female complaining of swelling of the buccal region. Intraoral examination showed a first-sized mass attached to the left molar gingiva of the mandible. The dark reddish mass was movable and had an elastic hard, and smooth surface, but the site of attachment could not be found. X-ray examination revealed small scattered radiopaque shadows suggesting calcification. Clinically, the lesion was suspected osteosarcoma, whereas biopsy section indicated no neoplastic feature. The excised specimen measured 90 × 80 × 55 mm and weighed 175 g. Histopathologically, the removed lesion was diagnosed as epulis osteoplastica. The patient's postoperative course was favorable 2 years after excision without any evidence of recurrence.

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