• The korean journal of orthodontics
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• v.26 no.6
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• pp.667-676
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• 1996

We have examined the in vitro stage-related chondrogenic potential of human mandibular and limb bud mesenchyme cells using micromass culture. Our results indicate that limb bud mesenchyme cells as early as stage 16 by Carnegie system (37 days), well before the initiation of in vivo chondrogenesis, have chondrogenic potential which is expressed in micromass culture. These results are correlated with stage-related chondrogenic potential of human limb bud in vivo as a result of Alcian blue staining. The proliferation of chondrogenic cells increased in the first 3 days after culture and then decreased. These results were correlated with the cell cycle analysis of which the number of $G_0^1/G_1$ phase increased markedly after 3 days of culture, while the percentage of cells in S phase was decreased. On the other hand, it was rarely differentiated in the mandible. We examined the effects of two PKC modulators such as phorbol 12-myristate 13-acetate (PMA), a potent activator of PKC, and staurosporine (STSN), an inhibitor of PKC. PMA inhibited the chondrogenesis, whereas STSN promoted the chondrogenesis in a dose dependent manner. In addition, PMA exerted no inhibitory effect when the cells were pretreated for 24 h with STSN, implying that the chondrogenic events might be settled at an early step in vitro and FKC may act as a negative modulator. Collectively, these results demonstrate, for the first time, the stage-related chondrogenic potential of human mandibular and limb bud mesenchyme cells and the role of PKC during chondrogenesis in vitro & in vivo.

• Animal cells and systems
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• v.13 no.3
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• pp.289-295
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• 2009

Cyclic AMP-mediated signaling pathways regulate a number of cellular functions. In this study, we examined the regulatory role of cAMP signaling pathways in chondrogenesis of chick limb bud mesenchymal cells in vitro. Forskolin, which increases cellular cAMP levels by the activation of adenylate cyclase, enhanced chondrogenic differentiation. Inhibition of PKA with specific inhibitors (H89 or KT5720) blocked pre-cartilage condensation stage, indicating that chondrogenesis is regulated by the increase in cellular cAMP level and subsequent activation of PKA. Downstream signaling pathway of PKA leading to gene expression was investigated by examination of several nuclear transcription factors. Forskolin treatment increased transcription level for a cartilage-specific marker gene Sox9. However, inhibition of PKA with H89 led to restore expression of Sox9, indicating PKA activity was required to regulate the expression of Sox9 in chondrogenesis. In addition, CREB was highly phosphorylated at early stage of mesenchyme culture, and followed by progressive dephosphorylation. CBP and ATF, another CRE related proteins were transiently expressed at the early stage of chondrogenesis with a pattern similar to CREB phosphorylation. Electrophoretic mobility shift assays confirmed that the binding activity of CREB to the CRE is closely correlated to the phosphorylation pattern of CREB. Therefore, cAMP-mediated signal transduction to nuclear events for the induction of genes appeared to be required at the early stage of chick limb bud chondrogenesis.

• Journal of the korean veterinary medical association
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• v.15 no.5
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• pp.259-260
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• 1979

A calf with an extra fore limb was born alive. The Korean cow was artificially inseminated. It was considered that in embryonic life, a part of fore limb bud was transfered to and developed on the skin of withers region.

• The Zoological Society Korea : Newsletter
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• v.12 no.2
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• pp.124.2-124
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• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.260.2-260
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• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.181.2-181
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• 1999

No Abstract, See Full Text

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.460-468
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• 1991

계배 limb bud간충직 연골원성 세포로부터 연골원세포로의 분화과정에서 Ca2+의 역할을 추구해 보기 위하여 Hamburger-Hamilton stage 23/24의 계배 limb bud간충직세포들을 미세배양법으로 배양하면서, Ca2+, calcium ionophore인 A23187, calcium channel blocker인 D600을 각각 농도 및 처리기간을 변화시켜 처리하면서 연골화의 정도를 검정하여, 연골세포 분화에 미치는 Ca2+의 작용양상을 분석하였다. 그 결과 Ca2+은 3 mM의 농도로 배양초기에 처리하였을 때 가장 효과적으로 연골화를 촉진하였으며, A23187(0.05 $\mu$ M) 처리는 세포내로 Ca2+유입을 증가시켜 연골화를 촉진시킨 반면, D6OO(30 $\mu$ M이하) 처리는 세포내로 Ca2+ 유입을 차단시킴으로서 연골화를 억제하는 것으로 나타났다. 이러한 결과에 따른 세포내로의 칼슘 유입 변화는 45Ca로 확인하였다. 그러므로 Ca2+에 의한 간충직세포의 연골세포로의 분화촉진 작용은 Ca2+이 연골화의 응집시기에 세포간의 접촉을 유도할 뿐만 아니라 배양 초기에 Ca2+이 세포 내로 들어감으로써 수반되는 일련의 기작에 의한 것임을 알았다.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.214.1-214
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• 1997

No Abstract, See Full Text

• Molecules and Cells
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• v.24 no.1
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• pp.139-147
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• 2007

Although transforming growth factors (TGFs) are implicated in the process of endochondral ossification, which is initiated by the differentiation of mesenchymal cells into chondrocytes, it is not clear how $TGF-{\beta}3$ regulates the chondrogenic differentiation of limb bud mesenchymal cells. Here, differential display polymerase chain reaction (DD-PCR) screening and RT-PCR analysis revealed that transcripts of A Disintegrin And Metalloprotease 10 (ADAM 10) decreased during the chondro-inhibitory action of $TGF-{\beta}3$ on cultured chick leg bud mesenchymal cells. Electroporation of ADAM 10 morpholino antisense oligonucleotides inhibited the ectodomain shedding of delta-1, and cell proliferation and subsequent precartilage condensation, in a manner similar to that caused by $TGF-{\beta}3$. The suppression of mesenchymal cell proliferation induced by $TGF-{\beta}3$ and ADAM 10 morpholino antisense oligonucleotides was reversed by activation of ADAM 10 with phorbol 12-myristate 13-acetate (PMA) or knockdown of Notch-1 with siRNA. Collectively, these data indicate that, in cultured chick leg bud mesenchyme cells, $TGF-{\beta}3$ downregulates ADAM 10 and inhibits cell proliferation and subsequent precartilage condensation by inhibiting the ectodomain shedding of delta-1, and that this results in the activation of Notch signaling.

• The Korean Journal of Zoology
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• v.38 no.1
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• pp.20-25
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• 1995

계배 limb bud 간충직 연골원성 세포로부터 연골세포로의 분화에 미치는 transforming growth factor-f2(TGF-$\beta$2)의 영향을 알아보기 위하여, Hamburger-Hamilton stages 23/24의 간충직 세포들을 미세배양법으로 배양하면서. TGF-$\beta$2의 농도 및 처리시간에 따른 연골세포의 분화에 미치는 영향을 조사하였다 그 결과 TGF-$\beta$2는 배양 첫 24시간 동안 1-2 ng/ml의 농도로 처리하였을 때 가장 효과적으로 연골세포의 분화를 촉진하였으며, 또한 TGF-$\beta$2의 처리군에서 배양 3일째에 tsss) sulfate의 glycosaminoglvcan으로의 유입량이 현저히 증가함을 보였다 한편. 배양 48시간내에TGF-$\beta$2를 처리한 경우 분화를 촉진 유도한 반면, 배양 48시간 이후에 처리하였을 때에는 분화 촉진 효과가 나타나지 않았다. 이상의 결과로부터 TGF-$\beta$2는 연골원 세포의 분화 초기단계에 세포외기질의 합성을 촉진시켜 세포응축을 유발하고. 세포-세포 및 세포-세포외기질의 상호작용을 증대시킴으로써 연골세포로의 분화를 촉진시킬 것으로 추정되었다.