Sand casting 3D printing uses a binder jetting method to produce a mold having complicated shape by spraying a binder on sand coated with activator. Appropriate heat treatment process in sand mold fabrication can increase the degree of polymerization to improve flexural strength. However, long heat treatment of over 24 hours decreases flexural strength and reliability due to chemical bond decomposition through thermal degradation. The main role of the activator is to control the reaction rate between the polymer chains. As a result, when the activator composition is increased from 0.15 wt% to 0.25 wt%, the flexural strength is increased by 218 N/cm2. However, excess activator (0.40 wt%) has been shown to decrease reliability without increasing flexural strength. The main role of the binder is to control the flexural strength of the specimen. As the binder composition is increased from 2.00 wt% to 4.00 wt%, the flexural strength increases to about 255 N/cm2, indicating the maximum flexural strength increase. Finally, the reliability of the flexural strength of the fabricated specimens is evaluated by a Weibull plot. Weibull modulus calculations are used to evaluate the flexural strength reliability of the specimens, and maximum reliability value of 11.7 is obtained at 0.20 wt% activator composition. Therefore, it is confirmed that this composition has maximum flexural strength reliability.

The human ELAV(embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellul ar mHNAs that contain AU- rich elements in their 3’ - untranslated region , To test the significance of HuR in carcinogenesis of head and neck squamous cell carcinomas(HNSCCs), we have investigated HuH expression from 32 benign epithelial lesions , 14 prema lignant epitheli al lesions and 80 HNSCCs, There were two different staining patterns of HuR in HNSCCs : nuclear expression was seen in 78 7% (63 of 80) 01' cases; and an additional cyto plasmic expression was seen in 28, 7%(23 of 80) 01 cases, Nuclear expression of HuR was s ignificantly increased in premalignant lesions and HNSCCs, whereas increased cytoplasπli c expression of HuR was only observed in HNSCCs Cytoplasmic HuR expression was significantly increased in pa tients of HNSCC younger than 60 yea rs , Al though there was no significant correlation between a natomic s ites of HNSCCs and HuR express ion , cyto plasmic HuR expression was highly increased in HNSCCs of larynx, There was no significant co rrela tion between HuR expression and other clinicopathological parameters such as histological type‘ tumor s ize‘ 0 1' n odal s tatus , ln conclusion, this study s uggests that overexpression of HuR in HNSCCs may be part of a regula tory pathway tha t co ntro ls the mHNA stability 0 1' several important targets in carcinogenesis of HNSCCs

Ameloblastic carcinoma is an ameloblastoma wi th histological malignant transformation with 01' without metastatic di sease_ We report an ameloblastic carcinoma ex ameloblastoma of right mandibular body in 7 -year-old girl with a heterogeneo us hi stologic components_ The tumor s howed so lid s heets composed of atypical kerati nized squamous cells. small ovoid cell s. and s pind le cells in addi tion to a bit of beni gn ameloblastoma component_ Immunohis tochemically, the squ amous cells were strongly cytokemtin posi ti ve/vimentin negati ve and the small ovoid and spindle ce lls were weakJy cytokeratin positi ve/v imentin pos it ive_

Human saliva conta ins a la rge number of proteins and peptides whose composition may alter as a conseq uence of disease. '1'0 date‘ however. the proteins and peptides that routinely populate t his oral fluid are largely unknown, '1'0 provid e a ca ta logue 이， sali va protei ns. we have surveyed the unstimulated human whole saliva by using shotgun proteomics. F'or the shotgun a pproach‘ whole sali va proteins were digested into peptides with ChemDigestD and the res ulting pe ptide fragments were sepa rated by RP- HPLC, followed by each fraction was tryptic di gestion ChemDiges tD- Trypsin diges ted pe pt ides were analyzed by tandem mass spectrometry (MS!MS) using a nano-LC equi pped quadru po le-time of fli ght rnass spect rometer, and the obtained spectra were searched against human protein sequence da tabase us ing MASCOT Shotgun proteomics a llowed a total of 291 human proteins to be confidently assigned. The largest gro u p (17 , 2%) of the identifi ed proteins sorted into functional categories was included in the s ignal transducti on function except for the hypothet ical or unknown functio n, This work provides a valuable starting point for the ana lys is of human sa l i va ry protei ns a nd theil‘ biological functions and candidates from human whole saliva that may prove to be of diagn ost ic and t herapeutic s ignif‘ Ica nce

The tumor suppressor gene, phosphate and tensin homologue(PTEN) has been shown to dephosphorylate the phosphatidylinositol 3-kinase(PI 3-K)-generated phosphatidylinositol(3-5)-triphosphate in vivo, thus interfering with the potentially oncogenic signals emanating from PI 3-K. Promoter hypermethylation of CpG islands has recently been shown to be an epigenetic change resulting in loss of function in some genes involved in cell cycle regulation and DNA repair. Immunohistochemal staining for monoclonal antibody 6H2.1 was performed from paraffin embedded blocks of 20 benign epithelial lesions and 40 head and neck squamous cell carcinomas(HNSCCs). Immunoreactivity was graded semiquantitatively by considering the percentage and intensity of the staining of the tumor cells. Also, this study tried to identify PTEN methylation in benign epithelial lesions(24 cases) and HNSCCs(44 cases of paraffin embedded blocks, 4 cases of frozen tissues) using methylation-specific PCR(MSP). In HNSCCs, immunoreactive scores of stage 1 and 2(12 cases, average score 85.2) were higher than those of stage 3 and 4(15 cases, 41.9) and statistically significant(P=0.017). Immunoreactive scores of moderate and poorly differentiated carcinomas(22 cases, 61.6) are more or less lower than those of well differentiated carcinoma(15 cases, 87.0) but not significant(P=0.361). Among 24 cases of benign epithelial lesions, 12 cases showed unmethylated PTEN but none methylated. In HNSCCs, 22 of 44 paraffin embedded blocks showed unmethylated PTEN but none methylated, and all 4 frozen tissue revealed unmethylated PTEN, one of which(25%) methylated. We consider that the loss of PTEN protein expression may be associated with the progression of HNSCCs and the other alteration rather than methylation may be important in the inactivation of PTEN in HNSCCs.

Genomic imprinting is defined as parent-of-origin expression of specific genes and may play an important role in embryonal development of mammals. Loss of imprinting(LOI), biallelic expression of the imprinted genes, have been observed in a variety of human tumors and syndromes. H19, a paternally imprinted gene, is transcribed as an untranslated RNA that serves as a riboregulator. LOI of H19 is observed in a variety of human malignancies. In this study, LOI of H19 was examined in head and neck squamous cell carcinomas(HNSCCs). Four(28.6%) of the 14 HNSCCs and 8(28.6%) of the 28 inflammatory oral lesions were informative for imprinting analysis of H19. H19 was imprinted in all inflammatory oral lesions, however, 2(50%) of the 4 informative HNSCCs manifested LOI. These data suggest that LOI of the H19 may play a role in the oncogenesis of HNSCC.

Phosphatase and tens in homologue(PTEN) 은 phosphatidylinosi t이 3'-kinase에 대해서 빈대로 작용함으로써 세 포픽 애 있는 지질 잔류인 phosphatidyl i nosi tol (3 - 5) - tri - phophate(PIP-3) 를 탈인산화시켜서 세포증삭의 자극에 대 한 막수용체의 반응을 조절하는 종앙억 제유전자이다 CpG islan ds의 promoter 메틸화가 세 포주기 의 조젤 이나 DNA 복구외 관런된 유진자 기 능을 소실시키는 것으로 알려지고 있으며. 두경부 편평세포암종에서 p16INK4a, p14ARF, p15‘ D뻐-K， E-Cadhe rin‘ GST-P. hMLH1의 메틸화가 보고되어 있다 두경부 편평세포암종에서 10번 염색체의 소실 이나 장완의 번이기 관칠되었으며. 이러한 유전적 변이의 배경에 PTEN 유전자가 있다 본 연구는 두경부 편평세포암종에서의 PTEN의 떼틸회 빈도와 단백발한 을 알아보고자 하였다 Methylation-specific PCR(MSP) 로 파라핀 포매조직 ( 양성 싱피증식성 병 소 25 이l. 두경부 편평 세 포암 종 44 예) 과 동결절편조직(두경부 떤평 세포암종 4 예)에 대해 PTEN의 메틸화 빈도를 확인하였다 양성 상피 증식 성 벙 소 20 예. 두경부 편평세포암종 40예의 파라핀 포매조직을 이용하여 PTEN 단클론항체인 6H21을 이용하여 변역 조직화학 엽색을 시행 하였다 염색강도와 염색된 부위의 백분율을 곱하여 반정량적으로 점수화하였으며 조직학적 동급 벙기외 임상적 변수애 따 라 분류하여 연역염색의 정수를 비교하였다 양성 상피증식성 병소 25 예 중 13예에서 메틸화되지 않은 PTEN을 보였으니 nl1 틸 화된 예는 없었다 두경부 편평세포암종의 경우 파라핀 포매조직 44예 중 22 예에서 매 틸화되지 않은 PTEN 을 보였으니 때 틸화된 예는 없었으며 4예의 동결절편조직 중 한 예에서 PTEN promoter부위의 베 틸화를 보였다 양성 상피 증식 성 병소와 두경부 편평세포암종의 면역조직화학 염색 평균점수는 각각 69 1과 705 였다 편평세포암종의 경우 임싱 적 벙기 를 1기와 271 를 하나의 군(12 예. 평균점수 852) 으로 3기와 471 를 다른 군 (15예‘ 41 ， 9) 으로 분류하여 비 교하았을 때 통제학적으로 유의한 차이 를 보였다(P=0 .017) 편평세포암종의 조직학적 분화도에 따라 고분화암종(15 예 87 ， 0) 과 중둥도분회 및 저분화암종 (22 예. 61 . 6) 으로 분류하였을 때 분화가 좋지 않을 수록 평균점수가 감소하는 경향을 보였으나 통계혁적으로 유의힌 차이 를 보이지 않았다(P=O ， 361)‘ 환자의 나이와 성별에 따른 차이는 없었다 본 연구결과， PTEN 단백 발현은 두경부 떤평 세 포임 종의 생 불 학적 행태 및 조직학적 둥급과 연관성이 있음을 시사한다. 두경부 편평세포암종 발임과정에서 prEN의 페 틸화는 관련성이 적 을 것으로 보이며， PTEN의 다른 유전적 맨이가 발암과정에 중요할 것으로 생각한다

HuR(human embryonic-Iethal abnormal vi sion-like protein, ELAV)은 최근 염증반응 및 세 포성장 조절의 중요 기전 으로 관심 을 받고 있는 전사후 유진자 발한의 조절기전 에 관여한다 HuR은 3' -untranslated regi on에 AU- rich ele rn ents(ARE) 를 지닌 일부 mRNA들(에‘ c- fos, VEGF. COX• 2 동)의 안정화에 기여하여 mRNA의 증가 및 부가적인 딘백발 한을 증가시킨디 HuR 단백 은 이 러한 염증 및 세포성장의 생리적 기전 외에 종양발생과도 관련될 수 있으며 ‘ 유방암 난소 암 및 뇌 종잉 둥에서 f-luR의 발한증가가 보고된 바 있다 두경부 편평 세 포암종 전암성 및 양성 편평세포 병소를 대상으로 HuR의 발현양상을 띤역 조직회학적으로 살펴봄으로써 HuR의 발현이 두경부 펀평세포암종의 발생과 관련될 수 있는지 실펴 보고자 힌다 본 인 구는 80여1 의 두경부 편평세포암종 14 예의 전암성 편평세포병소 및 32 예의 양성 면평세포벙소를 실험대상 으로 이용히였다 두경 부 편평세 포암종은 AJCC(Amcrican Joint Comrnittee on Cancer) 의 분류법에 의한 TNM분류 ， 병리 조 직학적 분화정 도 및 발생부위 별로 구분히였다 면역조직화학적 염색은 mouse anti-HuR monoclonal antibody(ZymeCl Clone 3A2) 와 Envis ion kit (DAKO) 를 이용하였다 염색결괴는 2명의 병리의사가 독립적으로 결과를 평가한 후 x 2 test fol' trends (SPSS‘ ve l'si o n12) 로 통계분석을 행하였다 HuR 염색반응을 핵과 세포질 부위로 구분하여 평가하고 비 교한 결과， 핵 과 세 포질 염색 결 괴 모두 편핑세 포암종 전암성병소. 양성병소에서 유의한 차이경향을 보였으며‘ 편평 세 포암종의 경우 임상벙 기 및 발생부위에 따른 유의 한 치이경향을 보였다 특히 ， 후두에서 발생힌 편평세포암종은 세포질애서 강한 양성반응을 보였 다 본 연구결과， mRNA 안정화 인자인 HuR의 발현 및 세포 내 분포가 두경부 펀평세포암종에서 이상조절 됨 을 보였으며 그 이싱 조절 양상이 두정 부의 부위별로 차이가 있음을 확인하였다 따라서 향후에는 발현이상의 downstream effec ts 및 이} 후와의 관련성에 대힌 연 구기- 추가되어야 할 것은 여져진다

Agi ng adversely affects the structure and function of the saliva ry gla nd and leads to ma rked insulin resis t ance that correlates with red uced ins ulin s ignal t ra nsduction, lnsulin-like g rowth factors are k.nown to be regulator involved in embryonic a nd postnatal development with sequences 62% identical t o that of proins ulin , To determine whether i n suli n- like growth facto l' - l, -2, - 1 receptor a l'e involved in the changes in rat salival'y gland by aging, we a na lyzecl the qua nti tation of 19f - 1, -2, - 1 rece ptor mRNA in l'at salivary glancl between 2 weeks and 26 months after bir th using the competiti ve reverse t ra nscriptase-polymerase chain reaction(RT-PCR) methocl Between 2 weeks ancl 2 months age, sharp falls in the qua nt ities of Igf-2 mRNA were observed, W11ereas Igf- 1 receptor mRNA rose by aging, but not sig nifïcantly, The quanti t ies of 19f- l kept by aging, These change seem to be involvecl a role fol' the Igf-2 in sali va ry c1evelopment a ncl earl y growth is incli ca ted, Thus, t he dras tic changes in the qua ntities of Igf-2 mRNA in the ra t sali va ry gla nd by aging seem to be in volved in the development, early growth and homeostasis of sali vary gla nd,

Metastatic spread to cervical lymph nodes(LNs) is a major determinant of outcome in oral squamous cell carcinoma (SCC). To provide an useful method for the detection of lymph node micrometastases, we fulfilled the histopathological examination and reverse transcriptase polymerase chain reaction(RT-PCR) using the paraffin-embedded LNs of oral SCC patients. In this study, 78 LNs from 12 patients with primary oral SCC were analyzed. Metastases in the regional LNs were evaluated by RT-PCR for squamous cell carcinoma antigen(SCCA) and cytokeratin 5(CK5). Detectability of metastatic LNs by RT-PCR was compared with histopathological examination. Of 78 LNs, CK5 and SCCA mRNA were detected in 32(41.0%) and 8(10.3%), respectively. Histopathologically, 10(12.8%) of 78 LNs were positive. CK5 mRNA was detected in all 10 histopathologically positive LNs. In contrast, SCCA mRNA was detected in 5 of 10 histopathologically positive LNs. These findings suggest that genetic diagnosis by RT-PCR based on CK5 mRNA expression may be sensitive and clinically useful technique to detect the presence of metastatic carcinoma cells in regional lymph nodes of oral SCC.

To cletermine the role of mismatch repair in the clevelopment of oral squamolls cell carcinomas (OSCCs) , the prevalence of microsatellite instability (MSI), expression of I뼈LH1 ancll띠SH2 ， ancl hypennethylation of I뻐LH1 ancl hMSH2 were explorecl. Bya panel of five markers (BAT25, BAT26 , 02S123, 05S346, ancl 017~‘250 ， the so-callecl Bethescla markers) for screening of MSI, MSI was observecl in 5 of the 15 sqllamolls cell carcinomas (33.3%). As MSI is callsecl by the clysfllnction of MMR genes, this stucly examinecl the methylation status of CpG sites in the hMLH 1 ancl hMSH2 promoters ancl the expression hMLH1 ancl hMSH2. Becallse of inappr이)riate efficiency of fonnalin-frxecl ancl paraffin-embeclclecl samples for methylation-specific PCR (MS-PCR) of hMLH1 ancl hMSH2, the role of promoter hypelmethylation 띠 the clevelopment of MSI ancl expression of hMLH1 ancl hMSH2. meùlylation was failecl to clefìne. However, loss of nllclear staining of 1ψIILH 1 ancl hMSH2 were seen in nine (69.2%) ancl four (30.7%) of 13 OSCCs, while four ancl fìve all corresponcling normal epiùlelial tisslles showecl positive nllclear stι ining ofl마ILH1 and hMSH2. These data suggest that MSI anclloss of expression of hMLH1 ancl hMSH2 play a role in the carcinc핑enesis of oral sqllamolls cell carcinomas thollgh the role of promoter hypermethylation of hMLH1 ancl hMSH2 in MSI and their expresslon IS lIncertam