Rushton bodies are known to be the aberrant keratinization and calcification in the epithelium of odontogenic cyst, which are similar to the features of calcifying odontogenic cyst and pilomatricoma. However, the pathogenetic mechanism of keratinization and calcification of Rushton bodies has not been clearly elucidated. Here, a case of Rushton bodies found in dentigerous cyst was examined by immunohistochemical method using antisera of PCNA, pAKT, HIF, PIM1, and PARP. The globular keratinization in lamellate fashion showed weak birefringency under polarizing microscope, and the Rushton bodies frequently underwent the dystrophic calcification. The polygonal keratinocytes of Rushton bodies were strongly positive for HIF and PARP, and the cyst epithelium was diffusely positive for pAKT and PIM1. Particularly, the cyst epithelium was hyperplastic and focally invaginated into cyst wall with positive reaction of PCNA. These findings may indicate the active response of odontogenic epithelium against the apoptotic stress of the cyst, producing the globular keratinization and irregular calcification in the polygonal keratinocytes. Therefore, it is presumed that the lamellate keratinization and dystrophic calcification of Rushton bodies are aberrant products of retrograding keratinocytes slowly undergoing apoptotic progresses similar to the phenomena of the ghost cells in calcifying odontogenic cyst and pilomatricoma, and also may have a potential for oncogenic proliferation.

Although the mechanism of the abnormal calcification in the calcifying odontogenic cyst (COC) was not elucidated so far, it has been known that the ghost cells are closely related to the calcification, producing dystrophic globular cementum-like materials, comparable to pilomatricoma in epithelium1). Here, we presented a case of COC occurred in left maxillary canine area of 23 years old female, exhibiting a collection of aberrant ossification admixed with basophilic ghost cells in comparison with seven cases of COC. In the polarizing microscope observation with Masson trichrome stain the present case clearly disclosed the typical birefringence of bony tissue, stained red in von Gieson stain, indicating the collagenous backbone. Some ghost cells showed the features of interdigitating epithelial attachments, empty spaces of nuclei, and reticular basophilic cytoplasms, which were similar to the basophilic ghost cells of philomatricoma. The present case demonstrated the aberrant ossification by basophilic ghost cells in COC similar to the ossification of pilomatricoma

Sparganosis is a rare parasitic disease caused by the infection of plerocercoid tapeworm larvae of the genus Spirometra. Up to date many cases of oral sparganosis had been diagnosed from biopsy specimens in Korea, however, in this study a 14 years old male showed an oral sparganosis in his buccal nodule producing its eggs, which were extruded through the ulcerated surface of buccal nodule. In the cytological observation for the pus‐like exudates many ovoid parasite eggs were found with a lot of inflammatory cells, which were mostly composed of eosinophilic polymorphonuclear leukocytes (PMNs). The eggs were measured about 50x50x80 μm, and had an operculum without opercular shoulder. In the subsequent biopsy examination the buccal nodule disclosed a diffuse granulomatous lesion with tunnel‐like spaces containing eosinophilic materials of parasite tegument, also infiltrated with a lot of eosinophilic PMNs. Therefore, we diagnosed it oral sparganosis producing its eggs with the characteristic features of sparganum granuloma in the cytological and histological observations, and also suggested that the cytological finding of parasitic eggs would be helpful to confirm the parasitic infection of sparganum matured enough to produce its eggs.

A 17-year-old male patient was referred for the extraction of impacted mesiodens and canine (#23) before orthodontic treatment. In the radiologic examination, an ovoid-shape radiolucent lesion was found with well-defined hyperostotic rim involved the teeth in left maxillary area. After biopsy examination the lesion was diagnosed as glandular odontogenic cyst (GOC) differentially from non-odontogrnic cysts, i.e., nasopalatine duct cyst. In the immunohistochemistry the cyst epithelium was freguently positive for PCNA, clearly positive for amtloblastin, slightly positive for β-catenin, but rarely positive for amelogenin and cytokeratin 7. Mucin and PRP were positive in the secretory cells of the cyst epithelium. On the other hand, TNFα was strongly positive in the macropahges infiltrated into the mucin-filled cyst lumen, and CD68 and CD31 were positive in the mucin-filled macropahges. These findings may indicate that the glandular elements are derived from hamartomatous secretory organ and that this odontogenic cyst is arisen from the embryonal rests of enamel epithelium, which has a potential to be differentiated into not only the enamel organ but also the secretory gland. Taken together, we assumed that the present case of GOC was originated from the odontogenic epithelium of impacted teeth, but showed the cytodifferentiation of glandular cells.

Oral squamous cell papillomas(OSCPs) showed various features in their etiology, histology, and prognosis. Therefore, it is necessary to diagnose differentially according to their pathological examinations. In the present study total 14 cases of OSCPs were evaluated and characterized to be three types of OSCPs, i.e., papillary papilloma, verrucous papilloma, and inverted papilloma. The present study demonstrated that among 14 cases of OSCPs papillary papilloma (n＝6) showed the typical papillary projection of squamous epithelium with severe acanthosis of upper spinous layer cells, accompanying frequent nuclear vacuolization. And verrucous papilloma (n＝7) showed the diffuse acanthosis of whole spinous layer cells with severe basal hyperplasia, resulted in the thick squamous epithelium exhibiting verrucous surface and irregularly ingrowing rete pegs. One case of inverted papilloma showed the typical ingrowth of basal layer cells deeply into underlying connective tissue, resulted in the formation of multiple fissures on the surface area. The present study also revealed the predominant nuclear vacuolization suspicious for viral infection in papillary papilloma, and also heavy smoking history in the verrucous papilloma. On the other hand, as the epithelium of inverted papilloma ingrew into the underlying deep connective tissue up to the muscular layer, it is supposed that the inverted papilloma has a potential of basal layer proliferation strong enough to invade the protecting barrier of underlying connective tissue, or that the underlying connective tissue was too weak to prevent the ingrowth of basal layer epithelium. Taken together, because the OSCPs show heterogenous origins and variable pathological prognosis, it is suggested that the OSCPs should be differentially diagnosed at least into three types, i.e., papillary papilloma, verrucous papilloma, and inverted papilloma.

Socket sclerosis can be an obstacle for orthodontic space closure, however, the precise histomorphogenetic mechanism has not been elucidated up to date. A 73 years old female complained of dull pain on palpation in the extraction site of the left maxillary first molar, and uncomfortable to use her complete denture. In panoramic X-ray view the socket sclerosis was clearly demarcated as a radiopaque outline of extracted root. In histological examination the socket sclerosis showed the basophilic deposition of cementum- like materials in the peripheral rim of trabecular bones instead of eosinophilic osteoid materials for intramembranous ossification. In the immunohistochemical staining for osteogenetic proteins, BMP-2 was strongly positive in the peripheral rim of trabecular bone, in which RANKL and osteoprotegerin were also consistently positive. Particularly, versican, a marker of cementum was also positive in the peripheral rim of the trabecular bone. Therefore, it is presumed that the trabecular bones of socket sclerosis were hypermineralized by cementoid ossification, producing cementum-like materials by osteoblasts/cementoblasts derived from the previous periodontium.

A 41-year-old male patient complained of a whitish growing mass on the central area of palate. The exophytic keratinizing mass was recently grown and showed rough surface localized at palatal mucosa. He has heavily smoked for more than 25 years. The lesion was clearly demarcated as an out-growing verrucous whitish epithelial lesion with erosive mucosa in the periphery and also continuous with the extensive hyperkeratosis in whole hard palatal mucosa. In the histological examination there appeared a plaque type verrucous hyperplasia in the absence of papillomatous growth. In the series of immunostains including PCNA, p53, β-catenin, APC, E-cadherin, BCL-2, MMP-1 and MMP-3 showed no features of infiltrative growth and malignant transformation. Therefore, the present case was diagnosed oral verrucous hyperplasia(OVH) different from squamous cell papilloma, verrucous leukoplakia, verrucous carcinoma, and oral squamous cell carcinoma.

Myositis ossificans traumatica(MOT) in head and neck area is a rare non-neoplastic, heterotopic bone formation within a muscle, arising after trauma or surgery. Although the several case reports have described the occurrence of MOT in other muscles of oro-facial musculature, MOT has never been reported in mentalis muscle. We demonstrate a case of MOT occurred in mentalis muscle of a 64 years old male. He recently complained of a movable mass with no pain. He had experienced a hitting trauma on his right anterior mandible about 25 years ago. Since then, the trauma area has been asymptomatic. The lesion showed severe muscular degeneration, resulted in a pseudocystic change without epithelial lining. The ectopic ossification was closely associated with the fibrous fascia of adjacent muscles. The lesion contained a lot of basophilic materials admixed with atrophying cells, which were supposed to be derived from muscle parenchyma injured previously. It was presumed that the basophilic materials induced callus-like ossification in the fibro-muscular lesion, also recruited macrophages and fibroblasts. However, the ossification processes in MOT were predominantly characterized by dystrophic calcification without osteoblastic differentiation of mesenchymal cells. Even more, there appeared some skeletal muscle bundles which were calcified dystrophically. Therefore, we suggest the present case of MOT might be initiated by dystrophic calcification in the degenerating muscle tissue

In the previous study it was demonstrated that most of sialolith contained bacterial colonies in their center of calcified laminated capsules1). Although it is still not determined whether the bacterial infection is a major pathogenic cause or not, many authors reported that the bacterial vegetation in sialolith can cause chronic suppurative inflammation in salivary gland. Actually a lot of different bacteria were found in oral cavity, most of them are non-pathogenic as normal flora, and only some of them are pathogenic for different mucosal infectious diseases. However, this study was aimed to identify a causative bacterial strain for the sialolith formation in human salivary gland. A strain of Bacillus subtilis (B. subtilis ) was found in the culture of sialolith, which was known to be a normal flora related to the fermentation of various Korean bean foods. In vitro culture experiment of B. subtilis it abundantly produced the thick biofilm aggregated around their cells and colony structure, which were subsequently attached on the surface of hydroxyapatite( HA) beads in scanning electronmicroscope(SEM) observation. The bacterial adherence on HA beads was strongest in the culture of B. subtilis, followed by Streptococcus mutans (Str. mutans ), oral mixed bacteria, and lactobacillus. Therefore, B. subtilis might be an important causative microorganism for the sialolithiasis in Korean people, and it is suggested that postmeal oral hygiene care should be required to reduce the number of normal flora, B. subtilis, after eating of fermented bean foods.

Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as Parkinson’s disease, Alzheimer’s disease, epilepsy and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a role in the pathogenesis of these diseases. The EtOH extracts of Viola mandshurica (NNMBS274), Viola patrinii (NNMBS275) and Viola papilionacea Pursh (NNMBS276), origin plants of Violae Herba, showed the potent neuroprotective effects on glutamate-induced neurotoxicity. Among them, NNMBS275, the extract of V. patrinii possessed the protective effects against glutamate toxicity by inducing the expression of heme oxygenase (HO)-1 in the mouse hippocampal HT22 cells. These results suggest that extracts of V. patrinii could be the effective candidates for the treatment of ROS-related neurological diseases. Furthermore, it is suggested that the protective effects of V. patrinii extract due to inducing the expression of HO-1 asAs the exfoliated keratinocytes (EKs) in oral mucosa are aging and degenerating cells, of which cytoplasms are almost replaced by cross-linked keratin materials. Consequently, the EKs become apoptotic with nuclear lysis. A question is arisen what is the biological role of these EKs in oral cavity? Are they simply degrading as aging keratinocytes or do they have some essential function still remained in the exfoliated status? The buccal smear samples from ten healthy adult subjects were observed under scanning electron microscope. On the outer surface of the EKs the features of bacterial adhesion were explored. The microorganisms attached on the surface of EKs were much deformed, shrunken and teared. Only a few microorganisms were found on the EK surface, aggregated focally. The attached microorganisms were gradually fused on the cell membrane of EKs, and subsequently endocytosed. Resultantly, many round endocytotic concave cavities similar size to the cocci were remained on the surface of EKs similar to the sequels of caveolae endocytosis. These data indicate that the degenerating EKs can actively engulf microorganisms attached on their cell surface via the processes of caveolae endocytosis. Therefore, it is presumed that the oral EKs still play a role for endocytotic scavenging of oral microorganisms using the denatured cell bodies themselves, which become highly adherent to oral microorganisms and still function for caveolae endocytosis in mixed saliva environment. an antioxidant/cytoprotective target

In the previous molecular cloning study from human salivary gland cDNA library novel clones (C75‐014, C76‐022) were known as candidate genes for proline rich proteins by GenBank data base search and RNA in situ hybridization. C75‐014 and C76‐022 genes were characterized as those expressing excretory basic proteins primarily composed of alanine, proline, and leucine residues, mimicking basic proline‐rich proteins (bPRPs) with helical structures and multiple consensus sequences of phosphorylation sites. In the immunohistochemical stainings using polyclonal antisera against each C75‐014 and C76‐022 peptide showed strong reaction in the secretory granules of striated and excretory ducts. And in Western blot for the different salivary specimens relatively distinctive bands appeared at lower molecular weight, ranging about 15‐50 kDa. This study was aimed to identify the molecular characteristics of C75‐014 and C76‐022 proteins, which showed properties of basic proline rich protein. These data suggest that C75‐014 and C76‐022 are candidate genes for proline rich proteins in human salivary gland, which may play a role for protecting and stabilizing the mucosal epithelium against numerous proteolytic damages and stresses.

To evaluate the biohazard properties of an extremely low frequency electromagnetic field (ELF-EMF), we explored the physical properties of the ELF-EMF that generates the electric current induction in the secondary coil from the chamber of a primary solenoid coil. We subsequently explored the biological effects of a strong alternating electromagnetic field (EMF), ranging from 730-960 Gauss, on the mouse testis. Mice were exposed to an alternating EMF field induced by a rectangular electric current at 1, 7, 20, 40, and 80 Hertz, for 1, 3, 5, and 7 hours. The mouse testes were examined for proliferative activity and apoptosis using the in situ terminal deoxynucleotidyl transferase (TdT) method and by immunostaining of proliferating cell nuclear antigen (PCNA), respectively. We found that the electric currentm induction increased in the 6-8 Hertz range, and that exposure to an ELF-EMF induced the apoptosis of mouse spermatocytes. In situ TdT staining was found to be most prominent in 7 Hertz group, and gradually reduced in the 20, 40, and 80 Hertz groups. These data suggest that a strong EMF can induce reproductive cell death within a short time, and the harmful effects of the EMF are maximal at low frequency alternating EMFs.

A 37 years old male patient had suffered from fibrous nasal polyp for more than 10 years even though careful medical treatment, and recently aggravated with severe nasal stiffness and pain. In the radiological observation the lesion was continuously extended into the ipsilateral maxillary sinus by poly cystic radiopacities gradually destroying the anterior wall of antrum. During the Caldwell-Luc operation a cystic fibrous granulomatous tissue was removed, and its microsections showed multicystic and tunnel-like spaces, of which lumens were usually round and filled with parts of parasitic worm e xhibiting parasitic t eguments and eggs. The granulomatous l esion showed relatively mild inflammatory reaction with the infiltration of eosinophilic PMNs. The histological features of tunnel-like penetration of parasitic worms, and their teguments and eggs were competent with the diagnosis of sparganosis. Especially, although the patient had no experience of raw foods such as frog or snake, he used to drink the untreated natural stream water obtained in the mountain area of Gangwon prefecture in Korea. Therefore, the present study demonstrated a rare lesion of antral spanganosis, and we suppose that the frequent incident of oral sparganosis in Gangwon prefecture is possibly related to the usage of untreated stream water in the mountain area of Gangwon prefecture in Korea

In the previous molecular cloning study from human salivary gland cDNA l ibrary a novel clone (C77-091) was known as a candidate gene for antimicrobial protein by GenBank database search and RNA in situ hybridization. This study is aimed to identify the molecular characteristics of C77-091 protein, which showed an antimicrobial activity on E.coli, thereby named as salivary antimicrobial protein (SAMP). SAMP consisted of a typical hydrophobic amino acid rich domain in the N-terminus, a cluster of basic amino acids, carbohydrate attachment site, a possible transglutaminase catalyzed cross-linking site, and multiple consensus sequences of phosphorylation site in the C-terminus. Western blot analysis of human organs and tissue with the monospecific antibody to the synthetic SAMP peptide showed strong interacting protein from the extracts from submandibular gland and parotid saliva but absent in the mixed saliva, and the immunohistochemical staining detected a strong positive regions in the secretory granules in the luminal cytoplasm of interlobular ductal cells of salivary gland. The SAMP was also distributed in the human sebaceous gland and prostate. These data suggest that C77-091 named SAMP gene is a novel antimicrobial protein in human salivary gland, which may play a role for the innate immunity by protecting and stabilizing the mucosal epithelium to maintain homeostasis of oral mucosa.

In order to unravel unidentified genes from human salivary gland, a cDNA library of human submandibular gland was constructed in the Uni‐ZAP XR vector by use of mRNA from human submandibular gland and ZAP‐cDNA® Gigapack® III Gold Cloning Kit. cDNA of salivary gland was subtracted with cDNA of immortalized human keratinocyte cell line, Rhim Human Epithelial Keratinocyte cell line. The phage cDNA library was converted into a pBluescript phagemid cDNA library, which was subsequently plated on LB plates with ampicillin, IPTG, and X‐gal, and white colonies were selected for sequencing. Among 200 clones analyzed, four clones containing C77‐091, C75‐014, C76‐022, and C76‐012 designated orphan genes that are intensely expressed in the interlobular ductal and serous acinar cells of human submandibular gland. Particularly C77‐091 gene expresses 46 amino acids peptide (pI=9.45). C75‐014 and C76‐022 genes were characterized as those expressing excretory basic proteins primarily consist of alanine, proline, and leucine residues, mimicking a basic proline‐rich protein (bPRP) showing helical structures and having multiple consensus sequences of phosphorylation sites. The strong expression of C76‐012 mRNA in the nuclei of salivary ductal and acinar cells suggests a role of C76‐012 gene as a DNA binding RNA/protein. These data suggest that the identification of four orphan genes from the human salivary glands may add further understanding of greater role of salivary proteins providing innate immunity by protecting and stabilizing the mucosal epithelium in the maintaining homeostasis of oral mucosa.

The eukaryotic translation initiation factor 5A (eIF5A) is a ubiquitous protein of eukaryotic and archaeal organisms which undergoes hypusination, and known to play pivotal functions for the synthesis of proteins involved in cell proliferation and cell cycle control. Its nuclear localization has an important implication for the eIF5A functions in nucleus, but the evidence of the nuclear translocation is still in controversy. This study is aimed to elucidate the nuclear localization of eIF5A in the epithelial cells of oral leukoplakia by the immunohistochemistry using trypsin digestion to remove their cytoplasms. The keratinocytes of the acanthotic and basal cell layers in oral leukoplakia showed the complete removal of their cytoplasmic components, but the nuclei of those cell layers were remained on the microsection. The immunostainings using both polyclonal and monoclonal antibody against eIF5A showed the strong positive reaction in the nuclei remained after trypsin digestion. And the immunostaining was more intensely expressed in the nuclei of the basal and suprabasal keratinocytes than in the nuclei of the upper spinous keratinocytes. These data directly indicate the post-translationally modified eIF5A is abundantly localized in the nuclear matrix components including nucleoli, which are resistant to the trypsin digestion. It is also presumed that the nuclear eIF5A localized at the trypsin resistant nuclear matrix, i.e., histone and r ibosomal proteins, may be closely relevant to the control of mRNA production or to the nuclear-cytoplamic trafficking for mRNA transportation.

Mucous retention cyst (MRC) is not uncommon in the pathology of maxillary sinus, which should be differentially diagnosed from chronic maxillary sinusitis. The main stream of diagnosis usually depends on the clinical symptoms and radiological findings. Thus it was sometimes puzzling to confirm the histological features of mucous retention phenomenon in the antral mucosa, when the specimen was from a limited portion or much degenerated by inflammatory reaction. This study aims to define the histopathological features of MRC through reevaluation of MRCs (n=19) and maxillary sinusitis (n=65) diagnosed previously. The present study classified three types of MRC, i.e., an extravasation type, a luminal retention type, and a mixed type of MRC. The extravasation type MRC showed clear pseudocyst cavity under sinus mucosa with infiltration of foamy macrophage, and the luminal retention type MRC showed mucous retention in the luminal cavity of maxillary sinus accompanied with inflammatory reaction, and the mixed type MRC showed the both features of extravasation and luminal retention type MRCs. Resultantly, among nineteen cases of MRC only three cases belonged to the extravasation type MRC, eleven cases belonged to luminal retention type MRC, and three cases belonged to mixed type MRC, while two cases were turned out to be postoperative residual cysts of maxillary sinus. The MRCs examined in this study showed different pathological features from ordinary maxillary sinusitis, exhibiting the typical mucin retention phenomenon of extravasation type or luminal retention type with relatively mild inflammatory reaction with infiltration of mucin-pooled macrophages. However, the luminal retention type MRC was predominant among the MRCs (11/17, 64.7%) and each of the extravasation and mixed type MRCs was only three cases out of 17 MRCs (17.6%). The extravasation type MRC characteristically produces a pseudocyst by the overexpressions of matrix metalloprotease-3 (MMP-3) and connective tissue growth factor (CTGF). Because not only the pathogenetic mechanism but also the prognosis of MRC is different from chronic maxillary sinusitis, we suggest that the MRC of maxillary sinus should be classified into extravasation, luminal retention, and mixed types in the histological observations in addition to the clinical and radiological informations.

As the human mixed saliva plays important roles for the protection, regeneration, immunity, and molecular transfer/ signaling in the oral and gastro-intestinal mucosa, the salivary contents have great implications for the general health of human body. Nevertheless, the analysis method of human saliva has not been well developed up to date, because the proteins of mixed saliva are rapidly interacted with each other and easily degraded by proteolytic enzymes and microorganisms. This study aims to develop an immunoprecipitation-based high performance liquid chromatography (IP-HPLC) for the analysis of human mixed saliva. The representative IP-HPLC analyses were performed to compare among different subjects in variable general conditions. Compared to the normal control the subjects suffered from bacterial infections of gastro-intestinal enteritis, chronic periodontitis, and acute necrotizing gingivo-stomatitis showed dramatic increase of LL-37 level depending on the severity of diseases, while the subject suffered from Herpes stomatitis, a viral infection showed great increase of β-defensin 2. These data indicate that LL-37 in human mixed saliva is more responsible to the bacterial infections of gastro-intestinal enteritis, chronic periodontitis, and acute necrotizing gingivo-stomatitis, while β-defensin 2 is more responsible to the viral infection of Herpes stomatitis. This study also suggeststhat the IP-HPLC be easily applicable to the wide range of biological samples for the quantitative analysis of an objective protein.

Krox-25, a Kruppel type zinc finger protein, may play an important role for the morphogenesis of tooth in ectomesenchymal interaction between enamel epithelium and odontogenic mesenchyme. The interrupted expression of Krox-25 by antisense inhibition is supposed to affect the abnormal development of tooth germ similar to the deranged proliferation of odontogenic tumors. This study was performed to know the histomorphogenetic effect of Krox-25 antisense inhibition in tooth germs of mouse embryos and to understand the abnormal expressions of Krox-25 in different odontogenic tumors which proliferate in aberrant direction of ecto-mesenchymal interaction. Total 95 tooth germs obtained from pregnant mice in the 13th day of fertilization were cultured with antisense oligonucleotides targeting mouse Krox-25 gene, and their histological patterns were compared with those of different odontogenic tumors, i.e., ameloblastic fibro-odontoma (n=5), ameloblastoma (n=8), and ameloblastic carcinoma (n=2). Resultantly, the cultured tooth germs treated with antisense oligodeoxynucleotides produced primitive dentine and enamel by odontoblasts and ameloblasts, respectively, but they aberrantly grew and formed abnormal tooth organs. Especially, the harmonious growth of enamel and dentine formation was greatly deranged by the antisense inhibition in the organ culture system. These findings were much similar to the abnormal growth of odontogenic tumors. The relatively well differentiated enamel epithelium of ameloblastic fibro-odontoma showed irregularly strong reaction of Krox-25, while the poorly differentiated enamel epithelium of ameloblastic carcinoma showed weak reaction. These data suggest that Krox-25 may play important roles for the histomorphogenesis of tooth germ by signaling the ecto-mesenchymal interaction between odontoblasts and ameloblasts in normal tooth germ development of mouse embryos as well as in cytodifferentiation of odontogenic tumors.

A patient complaining of severe pain in the right submandibular area showed a huge sialolith in radiogram. During the operation, the submandibular gland was much indurated, and large amount of pus was discharged out at an incision of the salivary gland. The removed salivary gland contained a huge sialolith in the major excretory duct of submandibular gland, which had an intact grayish-white surface in ovoid shape. In the histological examination its excretory ducts were extensively dilated without extravasation of saliva, and the involved salivary gland was almost destroyed by the granulomatous r eaction. Most of a cinar cells were d isappeared and r eplaced by ductal cells filled with exudative materials. The microsections of sialolith showed typical laminar structures of calcification containing amorphous basophilic material in the center, in which a lot of Gram positive and Gram negative microorganisms were found. In the center of sialolith numerous microorganisms were admixed with mucinous materials which were strongly positive for the antibody of mucin-1, and formed multiple colonies. In the periphery of the bacterial colonies proline rich proteins (PRPs) were condensely localized, and followed by the consistent positive reaction of transglutaminase 4 (TGase-4). These data suggest that the sialolith of this study is formed from the primary nidus of bacterial colony aggregated with salivary mucin-1 and PRPs by the crosslinking reaction of TGase-4.