Sung-Hee Jeong

Cytotoxicity and apoptosis induction of Bacillus vallismortis BIT-33 metabolites on colon cancer carcinoma cells

Aims:  The objective of this research was to isolate and identify a cytotoxic marine bacterium, BIT‐33, and to investigate the apoptosis effects of its metabolite on colon cancer cells.

Tumor necrosis factor-α and interleukin-1β expression pathway induced by Streptococcus mutans in macrophage cell line RAW 264.7

Streptococcus mutans, a major etiological agent of dental caries, frequently causes systemic disease, such as subacute bacterial endocarditis, if it enters the bloodstream. In this study, the production pathways of the proinflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), induced by S. mutans in mouse macrophage were examined using a quantitative real-time polymerase chain reaction and an enzyme-linked immunosorbent assay. The S. mutans stimulated the expression of TNF-α and IL-1β mRNA at a multiplicity of infection of 1 : 100, which increased at 2 and 4 h, respectively, to 24 h. It also induced the production of high levels of the TNF-α and IL-1β proteins, which increased at 2 h and reached a peak at 4 and 24 h, respectively. Nuclear factor-κB (NF-κB) was activated and reached a maximum level 30 min after the S. mutans treatment. The expression of TNF-α and IL-1β mRNA and protein was suppressed by the treatment with pyrrolidine dithiocarbamate, an NF-κB inhibitor. The S. mutans-induced TNF-α expression was suppressed by the presence of SB203580, a p38 mitogen-activated protein (MAP) kinase inhibitor, or SP600125, a Jun N-terminal kinase (JNK) MAP kinase inhibitor. On the other hand, IL-1β expression was inhibited by extracellular signal-regulated kinase (ERK)/p38/JNK MAP kinase inhibitor pretreatment. In addition, TNF-α production was suppressed more in the Toll-like receptor 2(-/-) (TLR2(-/-)) macrophages than in the TLR4(-/-) macrophages, whereas IL-1β production was suppressed more in the TLR4(-/-) macrophages than in the TLR2(-/-) macrophages. These results show that S. mutans stimulates the production of TNF-α and IL-1β in the mouse macrophage cell line, RAW 264.7, by activating ERK/p38/JNK, and NF-κB through TLR2 and TLR4, respectively.

Anterior condylar remodeling observed in stabilization splint therapy for temporomandibular joint osteoarthritis

OBJECTIVE To comparatively evaluate condylar surface bone formation and cortical thickening in patients with temporomandibular joint osteoarthritis, with or without stabilization splint (SS) therapy. STUDY DESIGN This retrospective study of 57 OA patients included 18 patients who had undergone SS therapy (SS group), compared with 39 patients that had not received SS therapy (non-SS group). To evaluate osseous changes on the condylar bone formation and cortical thickening, pre- and post-treatment cone beam computed tomography images of each patient were superimposed using voxel registration. RESULTS The SS group exhibited a higher ratio of bone formation in the anterior division of the condyle; the non-SS group exhibited mostly no change. The SS group was found to have higher frequencies of cortical thickening in the anteromedial, anterior-intermediate, anterolateral, posteromedial, and posterior-intermediate sections than the non-SS group. CONCLUSIONS SS therapy in temporomandibular joint osteoarthritis induced favorable bone remodeling in the anterior division of the condylar head.

Effect of stabilization splint therapy on glenoid fossa remodeling in temporomandibular joint osteoarthritis

PURPOSE The aim of this study was to evaluate, by CBCT superimposition, bone changes (cortical bone intactness, sclerosis and subchondral cyst) in the glenoid fossa related to stabilization splint (SS) therapy for temporomandibular joint osteoarthritis (TMJ OA) patients and to compare the effects for two groups, one that had undergone SS therapy and the other that had not. METHODS This case-control study included 36 TMJ OA patients, 10 that had undergone SS therapy (the SS group) compared with 26 that had not (the non-SS group). Osseous changes in the glenoid fossa were evaluated based on superimposed CBCT images before and after treatment. RESULTS Improvements ranging from 57.5 to 100% were achieved in cortical bone integrity, sclerosis, and subchondral cyst for both groups, SS and non-SS. However, there were no statistically significant difference between the two groups (p>0.05). The non-SS group showed a significant decrease in the distances from the point of inflexion and the lowest point of the articular eminence to the reference line (p<0.05). On the other hand, the SS group showed an increase for the point of inflexion. The other measures showed no statistically significant differences in distance before treatment and after treatment, even though the average distance after treatment showed an overall increasing tendency. CONCLUSION SS therapy relieved excessive loading on the TMJ in the TMD OA patients, who showed, via CBCT superimposition, less bone resorption in the glenoid fossa.

Pattern analysis of patients with temporomandibular disorders resulting from unilateral mastication due to chronic periodontitis

Purpose The purpose of the present study was to perform a pattern analysis in patients with temporomandibular disorder (TMD) resulting from unilateral mastication due to chronic periodontitis. Methods Thirty participants with signs or symptoms of TMD who engaged in unilateral mastication due to periodontitis-related discomfort (test group) were selected. Another 30 subjects exhibiting signs or symptoms of TMD resulting from unilateral mastication not due to chronic periodontitis (control group) were also recruited. An interview-based questionnaire was administered, and an examination of the temporomandibular joint (TMJ) with determination of periodontal status was performed. Results The duration of unilateral mastication was significantly longer in the control group than in the test group. There was a significant negative correlation between the duration of unilateral mastication and the Community Periodontal Index score. Using the Research Diagnostic Criteria for TMD (RDC/TMD) axis I algorithms, all the subjects were assigned to 3 main groups. The test group exhibited significantly a higher diagnostic distribution of group III (arthralgia, osteoarthritis, or osteoarthrosis), and in both the test and control groups, the number of diagnoses was larger for the non-chewing side. The control group showed a significantly higher diagnostic distribution of group I (myofacial pain), and in both the test and control groups, the number of diagnoses was larger for the chewing side. Conclusions The results of the present study indicate that unilateral mastication due to chronic periodontitis could induce not only pain but also structural TMJ changes if adequate treatment is not administered and supported within a short time from the onset of the condition. Therefore, immediate treatment of chronic periodontitis is recommended to prevent not only the primary progress of periodontal disease, but also secondary TMJ-related problems. Furthermore, subjects who have suffered chronic long-term periodontitis without treatment should be urged to undergo a TMJ examination.