• The korean journal of orthodontics
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• v.24 no.2
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• pp.295-301
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• 1994

The movement of teeth during orthodontic treatment requires bone remodeling process in periodontal tissue. To find out the changes occuring in the cell itself, mechanical force was applied to the cultured periodontal ligament cells. Following results were obtained from measuring the changes in cyclic AMP and $PGE_2$, $^3H$-thymidine incorporation amount in time lapse after application of mechanical force. 1. When mechanical force was applied to cultured PDL cells, the amount of cAMP in cells were increased significantly after 15 min. of force application, but were decreased gradually as time lapsed. 2. When mechanical force was applied to cultured PDL cells, the amount of PGE2 were increased at 20,40,60 min. and was significantly increased at 20 min. 3. When mechanical force was applied to cultured PDL cells, the amount of $^3H$-thymidine incorporation was some increased, but was not statistically significant.

• 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.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1074-1077
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• 2004

The effect of gradient eluted fractions from Et$_2$O extracts of Polyporus umbellatus screlotium was investigated on the viability of leukemia cell lines, K-562, L-1210, HL-60 and U-937 cells. Among those fractions, fraction 2 showed mild cytotoxic effect on L-1210 and HL-60 cells. Fraction 3 showed cytotoxic effect on 4 cell lines, and cytotoxic effect was the most potent on L-1210. The hallmark of apoptosis, DNA fragmentation, also appeared by fraction 3 on L-1210 after 48 hr treatment. Furthermore, this fraction was shown to be able to induce cell death on L-1210 cells by the inhibition of DNA synthesis in [$^3$H]thymidine incorporation test. From these results, P. umbellatus involves a potent chemical component that inhibits the viability of leukemia cell lines, L-1210. Further studies about the components of fraction 3 to function as a apoptosis inducer are necessary.

• Journal of Sericultural and Entomological Science
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• v.18 no.2
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• pp.1-60
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• 1976

In present study, radioautography and electron-microscopy were applied by the author to the elucidation of the mechanism of diapause in Bombyx mori L. (1). Patterns of nucleic acid and protein syntheses during embryonic development of silkworms, incubated at high and at low temperatures, were demonstrated by means of radioautography with labelled precursors of nucleic acid and protein. On the third day after blastokinesis the embryo incubated at high temperature generally incorporated much of the $^3$H-glycine into the brain and the suboesophageal ganglion, and some into other regions. When incubated at low temperature, no difference in the pattern between the brain, the suboesophageal ganglion and other parts was observed. Radioautography with $^3$H-thymidine revealed no significant difference in DNA synthesis in embryos incubated at high and low temperatures. In diapausing eggs twenty days after deposition, only a few cells of the mesoderm incorporated the labelled material into their nuclei, but in the hibernated eggs all the nuclei of the mesoderm had thymidine incorporation. After blastokinesis only the anterior portion of the embryo around the brain and the suboesophageal ganglion had thymidine incorporation; this was not observed in the posterior portion.

• The Korean Journal of Nuclear Medicine
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• v.36 no.4
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• pp.209-223
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• 2002

By considering the biological properties of a tumor, it should be possible to realize better results in cancer therapy. PET imaging offers the opportunity to measure tumor growth non-invasively and repeatedly as an early assessment of response to cancer therapy. Measuring cellular growth instead of energy metabolism showed offer significant advantages in evaluating therapy. Thymidine and its derivative nucleoside compounds can be changed to mono, di- and tri- phosphate compounds by thymidine kinase and then be incorporated into DNA. Their bindings are increased in highly proliferating cells due to the high DNA synthesis rate. To evaluate cell proliferation, many kinds of thymidine and uridine derivatives have been labeled with positron emitter and radioactive iodine. Compared to radiopharmaceuticals which have radioisotope labeled base ring such as pyirmidine, the radiopharmacuticals which have radioisotope labeled sugar ring are more stable in vivo and have metabolic resistance. The biological properties such as DNA incorporation ratios are highly dependent on their chemical structures and metabolic processes. This overview describes synthesis of radiopharmaceuticals and their biological properties for imaging of tumor cell proliferation.

• The Korean Journal of Zoology
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• v.22 no.2
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• pp.81-93
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• 1979

Metabolic changes of early mouse embryos treated with progesterone were investigated in order to elucidate the mode of action of progesterone on embryogenesis in vitro. The embryos were cultured, and labelled with radioactive precursors of macromolecules for certain periods in the absence or presence of various concentrations of progesterone by employing the microtube culture technique. The changes of transport and macromolecular synthesis systems of the embryos were examined by measuring the amounts of uptake and incorporation of the precursors. The results obtained were as follows: 1. Progesterone stimulated markedly the uptake of amino acids, but rather suppressed their incorporation by embryonic cells. 2. Progesterone suppressed both the uptake and incorporation of nucleotide precursors (uridine and thymidine) by embryonic cells. 3. Progesterone penetrated into the embryonic cell membranes and was taken up by them. The present results seem to indicate that the inhibition of the progesterone on the mammalian embryogenesis in vitro may not be directly related to the membrane transport system. They seem to imply that progesterone would penetrate into the embryonic cells and may directly block the biosynethetic pathways of macromolecules, and so lead to the inhibition of the embryogenesis in vitro.

• 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.

• 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)