• Biomedical Science Letters
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• v.12 no.3
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• pp.249-254
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• 2006

It has been reported that liver is a very important organ to xenotransplantation. Pig is known to be a most suitable species in transplantation of human organs. However, the physiological function of pig hepatocytes is not clear elucidated. Epidermal growth factor (EGF) is known to be a mitogen in various cell systems. Thus, we examined the effect of EGF on cell proliferation and its related signal cascades in primary cultured pig hepatocytes. EGF stimulates cell proliferation in a dose (>1ng/ml) dependent manner. EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by AG 1478 ($10^{-6}M$, an EGF receptor antagonist) genistein and herbymycin A (tyrosine kinase inhibitors, $10^{-6}M$), suggesting the role of activation and tyrosine phosphorylation of EGF receptor. In addition, EGF-induced increase of $[^3H]-thymidine$ incorporation was prevented by neomycin $(10^{-4}M)$, U73122 $(10^{-5}M)$ (phospholipase C [PLC] inhibitors), staurosporine ($(10^{-8}M)$, or bisindolylmaleimide I $(10^{-6}M)$ (protein kinase C [PKC] inhibitors), suggesting the role of PLC and PKC. Moreover, EGF-induced increase of $[^3H]-thymidine$ incorporation was blocked by PD 98059 (a p44/42 mitogen activated protein kinase [MAPK] inhibitor), SB 203580 (a p38 MAPK inhibitor), and SP 600125 (a JNK inhibitor). EGF increased the translocation of PKC from cytosol to membrane fraction and activated p42/44 MAPK, p38 MAPK and JNK. In conclusion, EGF stimulates cell proliferation via PKC and MAPK in cultured pig hepatocytes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.623-627
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• 2005

Abnormal thyroid cell proliferation has a very important role in hypothyroidism. Thyroid stimulating hormone (TSH) stimulates proliferation and maintains differentiated function in thyroid follicular cells. A functioning rat thyroid cell line (FRTL) was used to study the effect of Gamgung-tang (GGT, Glycyrrhizae Radix, black beans, Angelicae Radix and Cnidii Rhizoma) on proliferation and cAMP accumulation of thyrocytes. Proliferation of cell was assessed by DNA synthesis and incorporation of $[^3H]thymidine$ into DNA. The concentration of cAMP was measured simultaneously with growth assessment. Extract of GGT ($0.15{\sim}0.9\;mg/ml$ increased DNA synthesis in a dose-dependent manner. GGT at 0.6 (p<0.05) and 0.9 mg/ml (p<0.01) significantly increased $[^3H]thymidine$ incorporation. A comparable effect was observed with TSH. GGT also enhanced cAMP accumulation. These results indicate that GGT increases the proliferation of thyrocytes and may be considered a promising agent for the treatment of autoimmune thyroid disease.

• Preventive Nutrition and Food Science
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• v.4 no.3
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• pp.203-208
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• 1999

The effect of the polyunsaterated fatty acids, linoleic acid(LA), arachidonic acid(AA) and conjugated dienoic linoleic acid(CLA) on IEC-6 cells (rat intestinal cell)proliferation and cell transduction have been determined in vitro. IEC-6 cells proliferation was assessed by cell growth and [3H]-thymidine incroporation analysis. At 10 μM concentration , the proliferationof cells supplemented with AA or LA was significantly higher than that of CLA. [3H]-thymidine uptake showed the same results. LA and AA increased [3H]-thymidine uptake more than CLA. The stimulatory effect of LA or AA was even more pronounced in the presence of IGF. Both cell number analysis and [3H]-thymidine incorporation revealed that IEC-6 cell proliferation was influenced differently by exogenous free fatty acids, in which AA or LA stimulated IEC-6 cell proliferation and CLA inhibited it. Tyorosine phosphorylation provides a key switch to regulate celluar acitivity in response to extracellular stimuli. At 20 μM and 10μM, AA with IGF-1 stimulated protein tyrosine phophorylation in IEC-6 cells, but LA's impact was less than that of AA. CLA and CLA with IGF-1 inhibited protein tyrosine phosphorylation in IEC-6 cells. These results suggest there is a possible correlation between cell proliferation and IGF receptor tyrosine knase activity driven by AA.

• Development and Reproduction
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• v.4 no.2
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• pp.237-242
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• 2000

Growth hormone releasing hormone (GHRH), the major hypothalamic stimulus of GH secretion from the anterior pituitary gland, has been found to be present in several extrahypothalamic sites including placenta testis, ovary and anterior pituitary gland. The present study was performed to elucidate the role of pituitary GHRH on proliferation of cells derived from rat anterior pituitary gland. The GHRH content of pituitary tissue, cultured pituitary cells, and the conditioned media was evaluated by radioimmunoassay (RIA). Primary cultures of pituitary cells derived from adult rats were prepared by enzymatic dispersion. Significant amounts of GHRH-like molecules were detected in both pituitary tissue and cell cultures by GHRH RIA. Competition curves with increasing amounts of tissue extracts and conditioned media were parallel with those of standard peptide, indicating that the pituitary GHRH-like material is similar to authentic GHRH. To analyze specific cell types responsible for producing GHRH in anteroior pituitary, cell fractionation technique combined with GHRH RIA was performed. In cell fractionation experiment, the highest level of GHRH content was found in gonadotrope enriched-fraction and followed by somatotrope-, lactotrope- and thyrotrope-fraction. Treatment of pituitary cells with GHRH resulted in a dose-dependent increase in [$^3$H] thymidine incorporation. The mitogenic effect of GHRH could be mediated by typical oncogenic activation since the GHRH induced transient increase in c-fos mRNA levels with peak response at 30 minutes. The present study demonstrated that i) the pituitary GHRH expressed in the rat anterior pituitary gland can be secreted, ii) among the various cell types, gonadotropes and somatotorpes are the major GHRH source, and iii) the GHRH treatment increased the [$^3$H] thymidine incorporation and c-fos transcriptional activity in the pituitary cell culture. These findings suggested that GHRH could participated in the paracrine and/or autocrine regulation of cell proliferation, as well as promoting growth hormone secretion.

• Korean Journal of Veterinary Research
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• v.31 no.1
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• pp.49-53
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• 1991

The present study has been carried out to investigate the optimal condition on lymphocyte blastogenesis of rabbit lymphocytes, whole blood culture and microculture system in conjunction with a semiautomatic multiple sample harvester(SAMSH) was used to study the In vitro optimal condition of rabbit lymphocytes. Data were presented to show many variables that are involved in studying the phytohemagglutinin(PHA) and lipopolysaccharide(LPS) response of rabbit lymphocyte in a microculture system. Analysis indicated that the conditions for optimal PHA as measured by incorporation of $^3H$-TdR include: (1) use of RPMI-1640 as culture medium. (2) use of $6{\mu}g$ of PHA, per culture. (3) 48-hours culture period. Conditions for optimal stimulation with LPS mitogen were similar to those used for PHA.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.99-99
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• 2002

In the present study, the potent lipopolysaccharide (LPS)-mimetic stimulation of B cells and macrophages by hot water extract from Salicornia herbacea (S. europeae L.) is described. The extract activated spleen cells to proliferate in a dose-related manner as measured by [$^3$ H)-thymidine incorporation response.(omitted)

• Korean Journal of Food Science and Technology
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• v.5 no.3
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• pp.157-162
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• 1973

Mode of action study of irradiation was performed with potato tuber slices, $1mm{\times}1.5cm,$ aged on moist filter paper under aseptic technique. The time courses of invertase activity, nucleic acids and respiratory activity were determined, and sensitivities of these three processes to ionizing radiation were measured. None of those processes was severely inhibited by the dosage suppressing cell division. The result of $^3H-thymidine$ incorporation suggests that the reaction site of ionizing radiation might be existent during mitosis or $G_2$ period.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.83-93
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• 1985

The ability of $^{67}Ga$, administered carrier free as the citrate complex, to localize in human and animal tumors to an extent sufficient to permit visualization of the lesion by scanning is well established. However, neither the mechanism of $^{67}Ga$ uptake by tumors or inflammatory cells nor its relationship to cell type or to the biochemical status of the cell is yet understood. Author investigated the uptake of $^{67}Ga-citrate$ using subcellular tissue fractionation of rat livers treated with $CCl_4$ associated with the $^3H-thymidine$ incorporation rate to detect subcellular localization of $^{67}Ga$ and it's relationship in DNA synthesis. Large amounts of $^{67}Ga$ associated with the soluble portion of tissue homogenate rather than with isolated cell organelles and not related nuclei residue in the regenerating period after hepatocellular injury caused by $CCl_4$. The elevated uptake of $^{67}Ga$ in the livers of $CCl_4$ treated rats was also inhibited when protein synthesis was stopped by cyclohexamide. Thus protein and the soluble portion of issue homogenates seems to play an important role in the elevated uptake of $^{67}Ga$ in liver injury induced by $CCl_4$ treated rats.

• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.457-463
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• 2008

The sex steroid hormone estradiol-$17{\beta}(E_2)$ mediate their biological effects on development, differentiation and maintenance of reproductive tract and other target tissue through gene regulation by nuclear steroid receptors. Although the importance of $E_2$ in many physiological process has been reported, but little is known about the effects of $E_2$ on primary cultured chicken hepatocyte. therefore, in the present study, we have examined the effect of $E_2$ on cell proliferation and it's related signal cascades. $E_2$ increase $[^3H]$-thymidine incorporation in time-(${\leq}8hr$) and dose-($10^{-10}M$)dependent manner and treatment of $E_2$ increased the phosphorylation of p44/43 MAPKs(p44/42 mitogen-activated protein kinase) and JNK(c-Jun N-terminal kinase) in a time dependent manner. In addition, PD98059(p44/42 blocker, $10^{-5}M$), SP600125(JNK blocker, $10^{-6}M$) blocked the estrogen-induced increase in $[^3H]$-thymidine incorporation. In conclusion, $E_2$ stimulates the proliferation of primary cultured chicken hepatocytes and this action is mediated by p44/42 MAPKs and JNK signal transduction pathway.

• IMMUNE NETWORK
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• v.6 no.4
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• pp.199-203
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• 2006

Background: Eckol purified from Ecklonia cava, a brown alga has been known to have cytoprotective effects on some cell lines against oxidants and ionizing radiation. However, there is no study about the effects of eckol on immune cells. Methods: Bone marrow (BM)-derived dendritic cells (DCs) were used to demonstrate the immunomodulatory effects of eckol on DCs, such as viability, the expression of surface markers, allogeneic stimulating capacity using MTI, flow cytometric, $^3H$-thymidine incorporation assay. Results: Eckol did protect DCs against cytokine withdrawal-induced apoptosis in a concentration dependent manner based on MTT assay. And also, it increased the expression of MHC class II and CD86 (B7.2) molecules, maturation markers, on the surface of viable DCs gated in FACS analysis. Furthermore, eckol-treated DCs stimulated the proliferation of allogeneic $CD4^+$ T lymphocytes compared to imDCs in $^3H$-thymidine incorporation assay. $CD4^+$ T lymphocytes activated with eckol-treated DCs produced the larger amount of IFN-${\gamma}$ and IL-4 than those cells with imDCs. Conclusion: Taken together, we demonstrate in this study that eckol, a pure compound of Ecklonia cava, may modulate the immune responses through the phenotypic and functional changes of DCs.