• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.492-501
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• 1995

Background: Transforming growth factor- alpha(TGF-$\alpha$) may play important roles in carcinogenesis, tumor growth, and angiogenesis. Transforming growth factor-beta(TGF-$\beta$) are known to be involved in cell-cycle control and regeneration. TGF-$\alpha$ positively acts on growth control of many epithelial cells in contrast to the negative role of TGF-$\beta$. Method: To evaluate the possible role of TGF-$\alpha$ and TGF-$\beta$ in human primary lung cancers, the expression of TGF-$\alpha$ and TGF-$\beta$ were immmunohistochemically investigated in tissue sections from forty seven cases with lung cancers and ten cases with non-cancerous lung tissues. Recombinant cloned monoclonal antibody of TGF-$\alpha$ and neutralizing antibody of TGF-$\beta$ were employed as primary antibodies after dewaxing the formalin-fixed, paraffinized tissue sections. Results: TGF-$\alpha$ was expressed in the cytoplasms of tumor cells in thirty five cases of forty seven(74.5%) primary lung cancers, whereas the control expressed in two of ten brochial epithelial cells. The expression of TGF-$\alpha$ was disclosed in four cases of eleven(36.4 %) small cell carcinomas and thirty one cases of thirty six(86.1%) non-small cell carcinomas of the lung. Expressions of TGF-$\beta$ was discernible in bronchial epithelium in eight of ten non-cancerous lung tissues. The expression of TGF-$\beta$ was noted in the cytoplasms of tumor cells in eight cases of forty seven(17.0%) primary lung cancers. The expression of TGF-$\beta$ disclosed in two cases of eleven(18.2%) small cell carcinomas and six cases of thirty six(16.7%) non- small cell carcinomas of the lung. Conclusion: These findings suggest that up-regulation of TGF-$\alpha$ and down-regulation of TGF-$\beta$ are involved during development and growth of primary lung cancers.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.180-193
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• 2014

In plants, a shoot apex has a small region known as the shoot apical meristem (SAM) having a group of dividing (initiating) cells. The SAM gives rise to all the groundabove structures of plants throughout their lifetime, and thus it plays important role in growth and development of plants. This review describes theories to explain the SAM organization and function developed over the last 250 years. Since in 1759 German botanist C. F. Wolff has described firstly the SAM, in 1858 Swiss botanist C. N${\ddot{a}}$geli proposed the apical cell theory from the observation of a large single apical cell in the SAM of seedless vascular plants: however, this view was recognized to be unsuitable to seed plants. In 1868, German botanist J. Hanstein suggested the histogen theory: this concept subdividing the SAM into dermatogen, periblem, and plerome was unable to generally apply to seed plants. In 1924, German botanist A. Schmidt proposed the tunica-corpus theory from the examination of angiosperm SAM in which two parts show different planes of cell division: this theory was proved to be not suitable to gymnosperm SAM, not have stable surface tunica layer. In 1938, American botanist A. Foster described zones in gymnosperm SAM based on the cytohistologic differentiation and thus called it a cytohistological zonation theory. With works by E. Gifford, in 1954, this zonation pattern was demonstrated to be also applicable to angiosperm SAM. As another theory, in 1952 French botanist R. Buvat proposed the m${\acute{e}}$rist${\grave{e}}$me d'attente (waiting meristem) theory: however, this concept was confuted because of its negation of function during vegetative growth phase to central initial cells. Rescent studies with Arabidopsis thaliana have found that formation and maintenance of the SAM are under the control of selected genes: SHOOTMERISTEMLESS (STM) gene forms the SAM, and WUSCHEL (WUS) and CLAVATA (CLV) genes function in maintaining the SAM; signaling between WUS and CLV genes act through a negative feedback loop.