China did not join the Proliferation Security Initiative due to deep legal and policy considerations. China now has sufficient reasons to reappraise its existing stance in light of the establishment and continuous development of a positive, cooperative and comprehensive Sino-U.S. relationship, institutionalization of the PSI by U.S. President Barack Obama, and new changes in nuclear nonproliferation and disarmament. China’s participation in the PSI will be much more useful in enhancing the construction of international nonproliferation systems rather than remaining disengaged. Now it is the time for China to make the political decision and participate in the PSI.

In the modern climate of concern regarding rogue states and terrorists attacks following September 11th, the Proliferation Security Initiative, a new cooperative interdiction separate from treaties and multilateral export control regimes, is considered a useful tool in preventing the proliferation of Weapons of Mass Destruction. However, the Proliferation Security Initiative[j2] includes certain strategies that are in conflict with contemporary international law of the sea. On a bilateral and multilateral basis, the United States seeks to promote the international law-making process to achieve the goals of the PSI through the adoption of U.N. Security Council Resolution 1540, the conclusion of a bilateral boarding agreement, and the revision of the SUA Convention. Despite such efforts, the United States has made little progress towards achieving its goals. It is difficult to overcome generally accepted and established principles of flag states and freedom of navigation, even if there are certain potential threats to international peace and security caused by the proliferation of WMD.

Human fibroblasts that maintain the structural integrity of connective tissues by secreting precursors of the extracellular matrix are typically cultured with serum. However, there are potential disadvantages of the use of serum including unnatural interactions between the cells and the potential for exposure to animal pathogens. To prevent the possible influence of serum on fibroblast cultures, we devised a serum-free growth method and present in vitro data that demonstrate its suitability for growing porcine fetal fibroblasts. These cells were grown under four different culture conditions: no serum (negative control), 10% fetal bovine serum (FBS, positive control), 10% knockout serum replacement (KSR) and 20% KSR in the medium. The proliferation rates and viabilities of the cells were investigated by counting the number of cells and trypan blue staining, respectively. The 10% FBS group showed the largest increase in the total number of cells (1.09 × 105 eell₃/ml). In terms of the rate of viable cells, the results from the KSR supplementation groups (20% KSR:64.7%; 10% KSR: 80.6%) were similar to those from the 10% FBS group (68.5%). Moreover, supplementation with either 10% (30 × 104 eell₃/ml) or 20% KSR (4.8 × 104 cells/ml) produced similar cell growth rates. In conclusion, although KSR supplementation produces a lower cell proliferation rate than FBS, this growth condition is more effective for obtaining an appropriate number of viable porcine fetal fibroblasts in culture. Using KSR in fibroblast culture medium is thus a viable alternative to FBS.

Cyclosporine A (Cs A) which is a highly lipophilic cyclic undecapeptide mainly used for its immunosuppressive properties exert a wide spectrum of biological activities including fungicidal antiproliferactive, anti-inflammatory and chemotherapuetic effects. Human salivary gland adenocarcinoma is very aggressive characteristics, which is need to get the effective chemotherapuetic methods. Subconfluent SGT cell cultures have been treated with CsA at in vivo relevant concentrations for 24h. MTT assay for cellular proliferation of cultured SGT cell line has been performed and TGase 1 activity assay for cellular differentiation has been detected in the CsA-treated samples. It suggested that CsA could have an inhibitory effect in the proliferation of SGT cell line but no in the differentiation.

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.

Several lines of evidence suggest that osteocytes play a critical role in bone remodeling. Both healthy and apoptotic osteocytes can send signals to other bone surface cells such as osteoblasts, osteoclasts, osteoclast precursors, and bone lining cells through canalicular networks. Osteocytes responding to mechanical strain may also send signals to other cells. To determine the role for osteocytes an mechanical strain in bone remodeling, we examined the effects of fluid flow shear stress on osteoclast precursor cell and osteoblast proliferation and recruitment induced by osteocytes. In addition, the effects of fluid flow shear stress on osteocyte M-CSF, RANKL, and OPG mRNA expression were also examined. MLO-Y4 cells were used as an in vitro model for osteocytes, RAW 264.7 cells and MOCP-5 cells as osteoclast precursors, and 2T3 cells as osteoblasts. MLO-Y4 cells conditioned medium (Y4-CM) was collected after 24h culture. For fluid flow experiments, MLO-Y4 cells were exposed to 2h of pulsatile fluid flow (PFF) at 2, 4, 8, 16±0.6dynes/cm² using the Flexcell StreamerTM system. For proliferation assays, MOCP-5, RAW 264.7, and 2T3 cells were cultured with control media or 10-100% Y4 CM. Cells were cultured for 3d, and then cells were counted. RAW 264.7 and 2T3 cell migration was assayed using transwells with control media or 10-100% Y4-CM. M-CSF, RANKL and OPG in MLO-Y4 mRNA expression was determined by semiquantitative RT-PCR. Y4-CM increased osteoclast precursor proliferation and migration, but decreased 2T3 cell proliferation and migration. CM from MLO-Y4 cells exposed to PFF caused decreased RAW 267.4 cell proliferation and migration and 2T3 migration compared to control Y4-CM. However, Y4-CM from cells exposed to PFF had no effect on 2T3 osteoblastic cell proliferation. PFF decreased RNAKL mRNA and increased OPG mRNA in MLO-Y4 cells compared to control(without PFF). PFF had no effect on M-CSF mRNA expression in MLO-Y4 cells. These results suggest that osteocytes can regulate bone remodeling by communication with osteoclast precursors and osteoblasts and that osteocytes can communicate mechanical signals to other cells.

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

Mammalian Emx2. a homeobox tra nscripti on factor‘ is continuoll s ly expressecl in aclll lt neural s tem cell s of the b.ippo campal c1enclate gyrus (HDG) a f'ter blrth 1'0 c1ate‘ roles 01' Emx2 a ncl its llnderlying rnecha ni s rn in r eg비 atin g acl lllt neuro - genesis from neural stem cell aft er bi rth is still obscure. 1'he present experiment is aimed to elucidate role 01' Emx2 in regulating adll lt neurogenesis from neural s tem cell of HDG using nestin-Emx2 transgenic mouse (N-E2 1'G) and heterozygous Emx2 KO mouse (1-l-E2 KO) . HDG g ranlllar cell layer where new born neurons proclllced from adult neural stem cell migrate. is thin with low cell c1ens ity in N-E2 1'G but tbick with high cell density in H-E2 KO, compared to wild type mice (\\끼') . Number of DCX , a new born nellron marker. -positive cells is less in N-E2 1'G but more in l-l-E2 KO. comparecl to W1'. Ki67 (whole cell cycle marker) 01' BrclU (S-phase marker) 一positive cells is less in N-E2 1'G bllt morc in l-l-E2 KO and BrdU-positive cells/ Ki 67ratio is higher in N-E2 1'G but lower in H-E2 KO. NeuN (a mature n e llro삐 marker) a ncl BrdU-dollble positive cells is lUore in N- E2 TG bllt GFAP (a glial cell marker) ancl BrdU- dollble positive cells is more in ]-]- E2 KO. compa recl to WT 4wks after BrclU is aclmin istratecl one ti me per c1ay for 5days‘ Migrating c1egree of BrdU-positive cells is lower in N-E2 TG but higher in ]-]-E2 KO 4wks after BrclU is administratecl one t ime per day for 5days. Active casepase 3-positive cells is more in ]-]DG 01' the N-E2 TG but no changes in ]-]-E2 KO. 4 wks after CAG- GFP- PRE vector was inj ected in hippocampus. GFP-positive new born n e urons from aclult neural stem cell have less c1endritic branches in N-E2 1'G but more c1endritic branches in H-E2 KO‘ comparecl to the WT From these results. Emx2 transcription factor inhibits adult neurogenesis f'rom nellral stem cell of HDG throllgh reducing neural stem cell proliferation. new born cell survival. ce ll migration. ancl matllrat ion