"Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters,the system L amino acid transporters are the major nutrient transport system responsible for theNa+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter1 (LAT1), an isoform of system L amino acid transporter, is highly expressed in cancer cells to support their continuousgrowth and proliferation. 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid(BCH) is a model compound for studyof amino acid transporter as a system L selective inhibitor. We have examined the effect and mechanism of BCH on cellgrowth suppression in FaDu human head and neck squamous cell carcinoma. The BCH inhibited the L-leucine transportin a concentration-dependent manner with a IC 50 value of 43.8±4.3μM. The majority of L-leucine uptake is, therefore,mediated by LAT1 in FaDu cells. The growth of FaDu cells was inhibited by BCH in the time- and concentration-dependent manners. The formation of DNA ladder was not observed with BCH treatment in the cells.Furthermore, the proteolytic processing of caspase-3 and caspase-7 in the cells was not detected by BCH treatment.These results suggest that the BCH inhibits the growth of FaDu human head and neck squamous cell carcinoma throughthe intracellular depletion of neutral amino acids for cell growth without apoptotic processing. "

Traumatic eosinophilic granuloma(TEG) of the oral mucosa is considered to be a reactive benign condition. Histologyrevealed diffuse mixed infiltration of eosinophil and atypical mononuclear cells. We have described an additional case ofTEG simulating oral malignany where immunohistochemistry revealed the presence of CD30+ large atypical cells. TheCD30+ lymphoproliferative disorder(LPD) of oral mucosa, although rare, has also been described. In this case, there wasscattered distribution of CD30+ cells. After the incisional biopsy, the remainder of oral lesion got disappeared progressivelyand there is no sign of recurrence. We believe that this case could be a reactive rather than neoplastic process,and it has been suggested that a subset of TEG could be included within the spectrum of CD30+ LPDs. Therefore,oral surgeon and pathologists’ awareness of this condition will reduce the likelihood of misdiagnosis and inappropriateaggressive treatment for this benign, self-limiting lesion.

Cholesterol granuloma(CG) occurs frequently in association with chronic middle ear diseases, particularly diseases inthe mastoid antrum and air cells of the temporal bone, and much less frequently in paranasal sinuses. It occurs frequentlysecondary to massive hemorrhage of oral and paraoral cysts. However, It has never been reported to occur solelywithout any association with preexisting lesion in the mandible. We experienced development of unusual cholesterolgranuloma in the mandible. Seventy year old female presented diffuse hard swelling on the left mandibular area withlymphadenopathy of the left cervical lymph node. Radiographic examination showed a well circumscribed multilocular radiolucencyresembling soap bubble appearance with tooth displacement and root resorption, leading to the radiogrphicimpression of dentigerous cyst or odontogenic cyst or ameloblastoma. CT showed bucco-lingually undulating expansilelesion with corticated margin from the left posterior mandibular body to the anterior ramus, including #46, #47 and #48,and the mass showed slightly lower attenuation than muscle. leading to the impression of ameloblastoma. The mass aftersurgical excision composed of 2 sac like structures, measuring 4.0cm, and 2.7cm in diameter respectively. One sac wastightly attached to the #46, resembling dentigerous cyst.Microscopic examination showed a large number of cholesterol clefts in association with hemorrhage, hemosiderin pigmentsand foreign body giant cells. There was no evidence of cyst or other lesions.

Biological organisms require iron for optimal metabolism. Intracellular pathogens also must secure iron especially duringinfection of animal hosts expressing NRAMP(natural resistance-associated macrophage protein), a transporter proteinsequestering metal ions from pathogens. This study shows that extracytoplasmic function sigma factor σE is required forSalmonella virulence in NRAMP1-expressing mice, and further shows that iron deprivation turns on σE expression ofSalmonella. The virulence of σE -deficient Salmonella is completely attenuated in C3H/HeN mice while wild typeSalmonella kills all mice. Addition of an iron-chelator DTPA(Diethylene triamine pentaacetic acid) to culture media inducesσEexpression of Salmonella, but iron supplementation abrogates this induction. These findings suggest that ironlimitation in host macrophages can trigger σE -dependent virulence system of Salmonella that may include bacterial ironhomeostasis.

In this study, the apoptotic effects of the actin disruption agent, latrunculin B(LB) have been investigated on p53 deficientchronic myeloid leukemia cell line K562. A dose-dependent decrease in K562 cell proliferation was observed afterLB treatment with maximum decrease in cell proliferation being at 1.5μM where the percent inhibition was 66.53%.F-actin stained with TRITC-phalloidin was shown as a peripheral ring or appeared diffusely distributed throughout thecytoplasm in untreated cells, this actin ring was decreased following LB treatment, and even large focal actin aggregateswere formed. Treatment of K562 with LB(1.5μM) generated ROS substantially. LB activated expression in a dose-dependentmanner. Therefore it can be concluded that LB, depolymerising agent of actin, induces apoptosis by producingROS and up-regulating NF-kB and COX-2 activation.

The purpose of the present study is to investigate the optimal wavelength, frequency and energy density for set upthe photobiologic treatment of periodontal disease. To establish the present study,λscan of 500㎚to 900㎚ was used tosearch the optimal wavelength for maximal proliferation of human gingival fibroblasts. Cell proliferation assay was carriedout as MTT assay. Light intensity of 0.8 to 3.25mW, frequency of 0 to 584㎐and 0 to 2hours was applied for investigationof optimal energy density, frequency and applied duration. Finally, 628㎚ with 1mW/cm2 for 1hour of LED irradiationresulted in maximal proliferation of gingival fibroblasts. These results suggest that LED irradiation on gingivalfibroblast show different proliferation according to the condition of irradiation, and demonstrate that LED irradiationcan control the quantity of cell proliferation.

35 peri-implantitis recently referred for 10 years showed four types of inflammatory lesions, such as mild granulomatouslesion(n=5), severe granulomatous lesion(n=4), severe inflammatory fibrous scar tissue(n=15), severe abscessformation(n=11). However, the inflammatory lesions were usually localized at the peri-implant area accompanying compensatoryhyperplasia of fibrous connective tissue. The fibrous scar and the necrotic abscess frequently occurred dependon the severity of inflammatory reaction. Among 30 cases of severe inflammatory lesions, only 2 cases involved condensingosteitis in adjacent alveolar bone. Thus, we suppose that the inflammatory progression of peri-implantitis couldbe partly inhibited by the hyperplastic fibrous stromal tissue stimulated by implant material. And more, the focal abscessformed around the implant can be easily drainaged through the fibrous tract of implant pathway, resulted in thechronic persistent inflammatory granulomatous lesion, that is contrast to the common socket granuloma after toothextraction. However, depend on the degree of inflammatory reaction in the peri-implantitis the inflamed fibrous collagenoustissues, unregenerated graft materials, necrotic abscess and sequestra should be removed by surgical interventionand followed by antibiotic therapy, because the peri-implant tissue is as vivid as the normal periodontium for the inflammatorydefense system. Therefore, we suggest that the inflammatory lesions of peri-implantitis be carefully treatedto improve the prognosis for the following dental treatments.

Intracellular pathogens must maintain redox homeostasis against the antimicrobial actions of reactive oxygen and nitrogenspecies produced by host cells. This study proves that glutathione is required to promote survival of an entericpathogen Salmonella under the conditions producing reactive oxygen or nitrogen species. Glutathione is the non-proteinthiol compound distributed in a variety of organisms and possesses strong electron-donating capability to reduce intracellularredox environment. To examine the role of glutathione on Salmonella redox homeostasis under oxidative and nitrosativestress conditions, gshB gene encoding glutathione synthetase was mutated by the one-step PCR inactivationmethod. The growth of gshB mutant Salmonella producing virtually no glutathione was greatly impaired in the culturemedia containing either hydrogen peroxide or nitric oxide donors. The results suggest that physiological levels of glutathionecan provide a fundamental capability to maintain redox homeostasis for Salmonella in surviving oxidizing conditionsof host cells.

Low energy photon irradiation by light in the far red to near infrared spectral range(630~1000nm) using low energylasers or light emitting diode arrays has been found to modulate various biological processes in cell culture and animalmodels. The purpose of this study was to examine the light emitting diode irradiation effect on activity of normal humanosteoblast on titanium plate in vitro by various energy density, and to observe morphologic change of NHost on titaniumplate and to analysis concentration of Ca++, IP and ALP. NHost were cultured in DMEM containing 10% FBS, andobserved by inverted microscope for attatchment to the surface of titanium plate. Ca++, I.P., and alkaline phosphatase(ALP) concentration in medium was calculated during 4 weeks, which was treated with Wilcoxon rank, Anova testand linear regression. Morphologic changes showed LED produced in vitro increases of cell growth of 144~256% inNHost. During a culture period, Ca++ concentration was decreased. LED treatment(>3J/cm2) stimulate calcium consumptionin NHost. Statistically, a significant difference was not found between LED power density. LED treatedgroup(>3J/cm2) had higher total inorganic phosphate concentrations than control group in NHost. Statistically, a significantdifference was not found between LED power density. No significant changes were observed between ALP acitivityand LED treatment. In spite of LED power density, there were rapid growth rate of NHost and no significant ofCa++, IP and P concentration but these concentration showed predominant change than that of control.

The prominent side effect of cyclosporin A, immunosuppressive agent, in oral tissues is gingival overgrowth(GO). It ischaracterized by the gingival enlargement with epithelial thickening, a large number of proliferating fibroblasts andoverproduction of ECM components. Fibroblast accumulation in Cs A induced GO is caused by the Inhibition of apoptosis.But CsA effect on normal human oral keratinocyte(NHOK) remains unclear. Transglutaminase 2(TGase 2) which is expressedand activated in tissue where epithelial cells undergo apoptosis has been used as a marker for apoptotic cells.The purpose of this study were to study the effect of CsA on the proliferation and apoptosis of cultured NHOK by TGase2 expression. After primary cultured NHOK was treated by 0.1, 1.0 and 10ug/ml Cs A, growth curve, MTT assay forsuccinyl dehydrogenase activity and RT-PCR for TGase 2 mRNA expression were done. The obtained results were asfollows. MTT assay showed about 65% cell viability at 1.0μg/ml and 40% at 10μg/ml CsA. Growth curve showed normal Scurve on control & DMSO, while decreased growth rate after 3 days of higher CsA tx. TGase 2 mRNA expression of culturedNHOK was the highest at 10μg/ml Cs A. TEM showed chromosome margination, and vacuole formation and clusteredmitochodria in cytoplasm of cultured NHOK after CsA tx. It suggested that higher CsA might induce apoptosis ofNHOK correlated with increased TGase 2 mRNA expression.

To investigate the differential expression of genes by 635nm LEDs irradiation in arachidonic acid-treated human gingivalfibroblasts, cDNA microarray was carried out. Human gingival fibroblasts were primary cultured and arachidonicacid was treated to induce inflammation. 635nm of wave length was used for LEDs irradiation. The experimental groupwas categorized into four group ; control, only LEDs irradiation group, only arachidonic acid-treated group and arachidonicacid-treated with LEDs irradiation group. The expression of 8,078 genes were increased and the expression of7,103 genes were decreased in only LEDs irradiation group. For arachidonic acid-treated with LEDs irradiation group,the expression of 6,815 genes were increased, while the expression of 8,031 genes were decreased comparing with onlyarachidonic acid-treated group. IL-13alpha2 receptor was the most expressed gene in LEDs irradiation group comparingwith control, followed by MMP3. Genes which the most down regulated was BIRC3 in LEDs irradiation group. PLABgenes was the most up-regulated in arachidonic acid treated with LEDs irradation group, followed by ranked RARRES1.Considering the classification by cell function, genes associated with signal transduction were the most affected by LEDsirradiation, followed by the genes associated with nucleoside, nucleotide and nucleic acid metabolism. In arachidonic acidtreated with LEDs irradiation, genes associated with signal transduction and protein metabolism were affected.Taken together, LEDs irradiation could affect various biological process and could identify many genes related to LEDsirradiation, which could be used for clinical application.

The major component of green tea is (-)-epigallocatechin-3-gallate(EGCG) which accounts for 5080% of catechin,representing 200300 mg in a brewed cup of green tea. EGCG has been known to possess growth inhibitory andpro-apoptotic effect on human cancer cell lines such as prostate, bladder and breast cancers. In contrast, several studieshave suggested that EGCG could promote cell proliferation and/or survival instead of pro-apoptotic effect.Understanding how intracellular signaling pathways respond to EGCG may provide a clue to the difference of cell responsesand basis for usefulness of EGCG as a chemopreventive and/or chemotherapeutic agent.To better understand the mechanisms responsible for the chemopreventive efficacy of EGCG, the authors tried toidentify the key molecules that contributes to Akt activation and can inhibit this activation. In the present study, EGCGincreased Akt phosphorylation, an activeform of Akt and negatively affect on direct upstream molecules of Akt includingPTEN and EGFR, though Akt phosphorylation was increased.