Biomedical subjects

Sam-Pyo Hong

Publications and source records attributed to Sam-Pyo Hong.

9 recordsLinked to original sources

PubMed2006

Oligonucleotide microarray analysis of ameloblastoma compared with dentigerous cyst.

BACKGROUND: Ameloblastoma is a benign, but locally invasive tumor known for its high rate of recurrence. However, few comprehensive genetic studies have been conducted about its tumorigenesis. Our aim was to identify possible genes involved in the development and progression of ameloblastoma, using microarray analysis with dentigerous cyst as a control. METHODS: Total RNA was extracted from two fresh dentigerous cysts and ameloblastoma specimens. Following microarray analysis, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on selected genes. RESULTS: Seventy-three genes were overexpressed and 49 were underexpressed. These genes were divided into categories according to function. The microarray results for 13 selected genes were verified with semiquantitative RT-PCR. CONCLUSIONS: We identified important genes related to the development and progression of ameloblastoma through a large-scale gene expression analysis. This study will stimulate further investigations on genes significant for early diagnosis and prognosis of ameloblastoma.

Adolescent↗

PubMed2005

Hematogenous infection of the human temporomandibular joint.

Objective This study was designed to discover the relationship between bacteremia and the presence of specific bacterial species in the synovial fluid of the human temporomandibular joint (TMJ). Study design Sixteen volunteers (female to male, 1:2.2; average age, 30.00 +/- 9.93 years) who received operations via intraoral incision participated in this study. Samples from the blood and TMJ synovial fluid of the patients were taken preoperatively and postoperatively and analyzed by PCR assays with specific primers for the clinically important bacteria Staphylococcus aureus , Streptococcus mitis , and beta-hemolytic Streptococcus . Results PCR-based assays revealed the occurrence of S aureus in 68.8% and 50% of the total blood and synovial fluid samples collected immediately after the operations, which statistically differed from the preoperative samples ( P < .05). However, the frequency of the other bacteria, S mitis and beta-hemolytic Streptococcus , in pre- and postoperative blood samples had no such a difference ( P > .05). The chi-square test showed a significant association between the presence of S aureus in the blood and in TMJ synovial fluid (chi 2 = 6.409, P < .05), and the probability of hematogenous infection of the TMJ was estimated as 55.5%. Conclusion Hence, the data obtained provided evidence that the invasion of S aureus into TMJ synovial fluid was due to the presence of these bacteria in the blood. To our knowledge, this is the first report of the bacteremia-related mechanism of S aureus invasion in the human TMJ.

Adult↗

PubMed2005

The differential expression pattern of BMP-4 between the dentigerous cyst and the odontogenic keratocyst.

BACKGROUND: Bone morphogenic protein-4 (BMP-4) is widely expressed in oral cavity and involved in tooth morphogenesis, cellular differentiation and proliferation. The purpose of this study was to compare the difference in expression pattern of BMP-4 in odontogenic keratocysts (OKC) and dentigerous cysts (DC). METHODS: We evaluated 77 cysts, OKC (n = 34) or DC (n = 43). The average age of patients with OKC was 29.5 +/- 14.4 and that of patients with DC was 36.1 +/- 19.4. The male to female ratio was 20:14 for OKC and 27:16 for DC. Ten cases of OKC were recurrences. Expression of BMP-4 was determined by immunohistochemistry and in situ hybridization. RESULTS: The intensity scales were (-) for invisible or trace staining, (+) for visible staining, and (++) for dense, strong staining. OKCs exhibited the following staining patterns: the epithelium in 15/34 specimens and the mesenchymal cells in 17/34 specimens showed (++) stain. In contrast, the staining pattern of DC was (-) for epithelium in 37/43 specimens. The mesenchymal cells showed (-) degree staining in 30/43 specimens. The difference between the groups studied was significant (P < 0.001 in epithelium and mesenchymal cells). When recurrent and non-recurrent OKC were compared BMP-4 was expressed more intensely in the recurrent cases (P = 0.036 in epithelium). The difference in BMP-4 expression in mesenchymal cells was not significant. In situ hybridization demonstrated positive mRNA probes to BMP-4 were localized in epithelium and mesenchymal cells of OKCs and DCs. CONCLUSIONS: BMP-4 was expressed more intensely in OKC when compared with DC, and was more intensely expressed in recurrent cases.

Adult↗

PubMed2004

Inactivation patterns of p16/INK4A in oral squamous cell carcinomas.

The p16/INK4A is one of the major target genes in carcinogenesis and its inactivation has frequently been reported in other types of tumors. The purpose of this study is to evaluate inactivation patterns of p16/INK4A in oral squamous cell carcinoma. Six different oral cancer cell lines, SCC-4, SCC-9, SCC-15, SCC-25, KB, and SNUDH- 379 were examined for inactivation of p16/INK4A genes. In the analysis of p16/INK4A gene inactivation, PCR amplification, direct sequencing, and methylation-specific PCR methods were adopted for evaluation of homozygous deletion, point mutation, and promoter hypermethylation, respectively. Homozygous deletion was detected in SCC-25 and SCC-9. SCC-15 showed hypermethylated promoter region within p16/INK4A gene. It is suggestive in the present study that inactivation patterns of p16/INK4A were mainly homozygous deletion, promoter methylation rather than point mutation in oral squamous cancer cell lines, so treatment modalities of oral squamous cell carcinoma should be focused on these types of inactivation.

Carcinoma, Squamous Cell↗

PubMed2003

Transforming growth factor-alpha and oral fibroma: Immunohistochemical and in situ hybridization study.

PURPOSE: Transforming growth factor-alpha (TGF-alpha) is usually expressed in cell lines derived from sarcomas. It is known as a mitogen for fibroblasts. The aim of this study was to determine whether there were any differences in the expression pattern of TGF-alpha between normal oral mucosa and oral fibroma. PATIENTS AND METHODS: Fourteen pathologic specimens (6 males and 8 females; 37.2 +/- 23.2 years) and 10 normal oral mucosal specimens (5 females and 5 males; 43.8 +/- 17.7 years) were used for this study. Identification of TGF-alpha was sought by using immunohistochemistry and in situ hybridization. RESULTS: The samples from normal oral mucosa did not express TGF-alpha. One sample from oral fibroma did not express TGF-alpha (7.1%). Five samples from oral fibroma expressed TGF-alpha sparsely (35.7%). Eight samples showed diffuse expression of TGF-alpha (57.1%). The immunopositive reaction to TGF-alpha in oral fibroma was localized in the basal layer and the fibroblasts that resided beneath the epithelium. This pattern was also shown in the in situ hybridization study as well. CONCLUSION: TGF-alpha is expressed in oral fibromas. It suggested that TGF-alpha might play a role in fibroblast proliferation in oral fibromas.

Adult↗

PubMed2003

The presence of bacteria in the synovial fluid of the temporomandibular joint and clinical significance: preliminary study.

PURPOSE: The objective of this study was to find any relation between the presence of specific bacterial species in the synovial fluid of the temporomandibular joint (TMJ) and clinical parameters. PATIENTS AND METHODS: We studied 43 patients (male-to-female ratio, 1:1.69; average age, 34.37 +/- 14.55 years). Thirty-three patients had a displaced disc in the TMJ (DD group), and 10 patients did not have a displaced disc of the TMJ or any symptom related to TMJ disorders (NDD group). Clinical examinations were made to determine maximum mouth opening, joint sounds, previous trauma history, systemic disease, and TMJ pain. Six bacterial species that were reported in other studies were chosen to evaluate the presence of bacteria in the TMJ for this study. RESULTS: Mycoplasma genitalium was most frequently detected in synovial fluid (86.0%). Staphylococcus aureus, Mycoplasma fermentans/orale, Actinobacillus actinomycetemcomitans, and Streptococcus mitis were detected in 51.2%, 37.2%, 25.6%, and 7.0% of samples, respectively. beta-Hemolytic Streptococcus was not detected. The prevalence of S aureus was significantly higher in the DD group than in the NDD group (P <.05). The patients who had M. fermentans/orale were 5.40 times more likely to be younger than 30 years than were those without M. fermentans/orale (P <.05). Those with M. genitalium were 5.81 times more likely to be female than were those without M. genitalium (P <.05). CONCLUSION: The presence of S. aureus in TMJ synovial fluid was related to TMJ disorder symptoms and clinical parameters seemed to be influenced by bacterial presence in TMJ synovial fluid.

Adult↗

PubMed2003

Ganglion cyst of the temporomandibular joint.

We report a case of cystic lesion in a 37-year-old woman. The patient had an oval-shaped lesion adjacent to the temporomandibular joint. Thick fibrotic tissue and muscle were observed microscopically, but the epithelium lining was not observed. The lesion was diagnosed as a ganglion cyst. The patient's general medical history was non-contributory. High performance liquid chromatography (HPLC) and mass spectrophotometry (MS) revealed some proteins from the fluid in the lesion, such as a filaggrin precursor, dystroglycan, a polyprotein of the hepatitis C virus, and proteins originating from bacteria. The follow-up examinations revealed no recurrence. The probable pathogenesis of the lesion is discussed.

Adult↗

PubMed2003

Anti-cancer effect of genistein in oral squamous cell carcinoma with respect to angiogenesis and in vitro invasion.

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck cancers. OSCC generally has a poor prognosis due to its tendency towards local invasion and subsequent metastasis, which is mediated by multiple proteolytic enzymes and angiogenesis. The purpose of this study was to evaluate the anti-cancer effects of genistein, a soybean product known to be an effective natural anti-angiogenic agent, with respect to tumor growth, angiogenesis and in vitro invasion in an OSCC model. Northern blot analysis for vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and matrix metalloproteinase-2 (MMP-2), in vitro invasion assay and gelatin zymography were carried out for HSC-3 cells treated with genistein (27.3 microg/ml). In the animal experiment, genistein (0.5 mg/kg) was injected into tumor (HSC-3)-bearing mice (male balb/c/nu). The tumor growth rate and metastasis to lymph node or lung were compared and the microvessel density (CD31) was subsequently analyzed by immunohistochemistry. The genistein-treated group showed a down-regulation in VEGF mRNA expression, but not in bFGF and MMP-2 mRNA expression. Genistein reduced in vitro invasion through the artificial basement membrane and gelatin zymography also showed a reduced gelatinolytic activity in the genistein-treated group. In the genistein-treated mice, a significantly lower CD31 immunoreactivity was found. However, the tumor growth and metastatic behavior in the experimental group and the control group were similar and there were no significant differences. These results suggest the possible use of genistein as an anti-cancer agent in oral squamous cell carcinoma. However, it appears from the present study that anti-angiogenic therapy consisting of a single application of genistein may not provide a satisfactory treatment for OSCC. As a result, further research is recommended to confirm that genistein may be employed as an adjunct treatment modality for OSCC.

Angiogenesis Inhibitors↗

PubMed2002

Expression of membrane type I-matrix metalloproteinase in oral squamous cell carcinoma.

A local invasion and lymph node metastasis (LNM) of an oral squamous cell carcinoma (OSCC) has a poor prognosis, and involves the degradation of the extracellular matrix mediated by multiple proteolytic enzymes including membrane type I-matrix metalloproteinase (MT1-MMP). This study aimed to determine the role of MT1-MMP in OSCC, to evaluate the immunohistochemical expression of MT1-MMP with regard to the invasiveness and LNM of the OSCC, and to evaluate the major source of MT1-MMP mRNA and its protein using immunohistochemistry and in situ hybridization. MT1-MMP expression was examined in 46 OSCCs via immunohistochemistry and non-radioisotope in situ hybridization. The relationship between MT1-MMP expression and LNM, as well as the histological invasiveness, was statistically analyzed. The results showed that whereas 12 out of the 18 OSCCs (66.7%) with LNM showed moderate to strong MT1-MMP expression, only nine of the 28 OSCCs (32.1%) without LNM expressed MT1-MMP strongly. MT1-MMP expression was significantly higher with regard to LNM (P=0.022). As the invasion grade became stronger (from grade a to grade d), MT1-MMP was significantly more strongly expressed (P=0.033). These results suggest that MT1-MMP is primarily secreted in the OSCC cells and is involved in the invasiveness of the OSCC and LNM. Moreover, MT1-MMP combined with other markers may be used to predict the metastatic potential of an OSCC.

Adult↗