The family members of the mitogen-activated protein (MAP) kinases mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the four main sub-groups, the p38 group of MAP kinases, serve...The family members of the mitogen-activated protein (MAP) kinases mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the four main sub-groups, the p38 group of MAP kinases, serve as a nexus for signal transduction and play a vital role in numerous biological processes. In this review, we highlight the known characteristics and components of the p38 pathway along with the mechanism and consequences of p38 activation. We focus on the role of p38 as a signal transduction mediator and examine the evidence linking p38 to inflammation, cell cycle, cell death, development, cell differentiation, senescence and tumorigenesis in specific cell types. Upstream and downstream components of p38 are described and questions remaining to be answered are posed. Finally, we propose several directions for future research on p38.展开更多
Background The two most basic properties of mesenchymal stem cells （MSCs） are the capacities to selfrenew indefinitely and differentiate into multiple cells and tissue types. The cells from human umbilical cord Whar...Background The two most basic properties of mesenchymal stem cells （MSCs） are the capacities to selfrenew indefinitely and differentiate into multiple cells and tissue types. The cells from human umbilical cord Wharton＇ s Jelly have properties of MSCs and represent a rich source of primitive cells. This study was conducted to explore the possibility of inducing human umbilical cord Wharton＇ s Jelly-derived MSCs to differentiate into nerve-like cells.Methods MSCs were cultured from the Wharton＇ s Jelly taken from human umbilical cord of babies delivered after full-term normal labor. Salvia miltiorrhiza and [3-mercaptoethanol were used to induce the human umbilical cord-derived MSCs to differentiate The expression of neural protein markers was shown by immunocytochemistry. The induction process was monitored by phase contrast microscopy, electron microscopy （EM）, and laser scanning confocal microscopy （LSCM） . The pleiotrophin and nestin genes were measured by reverse transcription-polymerase chain reaction （RT-PCR）.Results MSCs in the Wharton＇ s Jelly were easily attainable and could be maintained and expanded in culture. They were positive for markers of MSCs, but negative for markers of hematopoietic cells and graft-versus-host disease （GVHD）-related cells. Treatment with Salvia mihiorrhiza caused Wharton＇ s Jelly cells to undergo profound morphological changes. The induced MSCs developed rounded cell bodies with multiple neurite-like extensions. Eventually they developed processes that formed networks reminiscent of primary cultures of neurons. Salvia mihiorrhiza and β-mercaptoethanol also induced MSCs to express nestin, β-tubulin Ⅲ, neurofilament （NF） and glial fibrillary acidic protein （GFAP）. It was confirmed by RT-PCR that MSCs could express pleiotrophin both before and after induction by Salvia miltiorrhiza. The expression was markedly enhanced after induction and the nestin gene was also expressed.Conclusions MSCs could be isolated from human umbilical cord Wharto展开更多
Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induce...Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.展开更多
AIM:The prognosis of early gastric carcinoma (EGC) is generally excellent after surgery. The presence or absence of lymph node metastasis in EGC is an important prognostic factor. The survival and recurrence rates of ...AIM:The prognosis of early gastric carcinoma (EGC) is generally excellent after surgery. The presence or absence of lymph node metastasis in EGC is an important prognostic factor. The survival and recurrence rates of node-negative EGC are much better than those of node-positive EGC. This study examined the factors related to lymph node metastasis in EGC to determine the appropriate treatment for EGC.METHODS: We investigated 748 patients with EGC who underwent surgery between January 1985 and December 1999 at the Division of Gastroenterologic Surgery, Department of Surgery, Chonnam National University Hospital. Several clinicopathologic factors were investigated to analyze their relationship to lymph node metastasis: age, sex, tumor location, tumor size, gross type, histologic type, depth of invasion, extent of lymph node dissection, type of operation,and DNA ploidy.RESULTS:Lymph node metastases were found in 75 patients (10.0%). Univariate analysis showed that male sex, tumor size larger than 2.0cm, submucosal invasion of tumor, histologic differentiation, and DNA ploidy pattern were risk factors for regional lymph node metastasis in EGC patients. However, a multivariate analysis showed that three risk factors were associated with lymph node metastasis:large tumor size, undifferentiated histologic type and submucosal invasion. No statistical relationship was found for age, sex, tumor location, gross type, or DNA ploidy in multivariate analysis. The 5-year survival rate was 94.2% for those without lymph node metastasis and 87.3% for those with lymph node metastasis, and the difference was significant (P<0.05).CONCLUSION: In patients with EGC, the survival rate of patients with positive lymph nodes is significantly worse than that of patients with no lymph node metastasis. Therefore,a standard D2 lymphadenectomy should be performed in patients at high risk of lymph node metastasis: large tumor size, undifferentiated histologic type and submucosal invasion.展开更多
文摘The family members of the mitogen-activated protein (MAP) kinases mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the four main sub-groups, the p38 group of MAP kinases, serve as a nexus for signal transduction and play a vital role in numerous biological processes. In this review, we highlight the known characteristics and components of the p38 pathway along with the mechanism and consequences of p38 activation. We focus on the role of p38 as a signal transduction mediator and examine the evidence linking p38 to inflammation, cell cycle, cell death, development, cell differentiation, senescence and tumorigenesis in specific cell types. Upstream and downstream components of p38 are described and questions remaining to be answered are posed. Finally, we propose several directions for future research on p38.
文摘Background The two most basic properties of mesenchymal stem cells （MSCs） are the capacities to selfrenew indefinitely and differentiate into multiple cells and tissue types. The cells from human umbilical cord Wharton＇ s Jelly have properties of MSCs and represent a rich source of primitive cells. This study was conducted to explore the possibility of inducing human umbilical cord Wharton＇ s Jelly-derived MSCs to differentiate into nerve-like cells.Methods MSCs were cultured from the Wharton＇ s Jelly taken from human umbilical cord of babies delivered after full-term normal labor. Salvia miltiorrhiza and [3-mercaptoethanol were used to induce the human umbilical cord-derived MSCs to differentiate The expression of neural protein markers was shown by immunocytochemistry. The induction process was monitored by phase contrast microscopy, electron microscopy （EM）, and laser scanning confocal microscopy （LSCM） . The pleiotrophin and nestin genes were measured by reverse transcription-polymerase chain reaction （RT-PCR）.Results MSCs in the Wharton＇ s Jelly were easily attainable and could be maintained and expanded in culture. They were positive for markers of MSCs, but negative for markers of hematopoietic cells and graft-versus-host disease （GVHD）-related cells. Treatment with Salvia mihiorrhiza caused Wharton＇ s Jelly cells to undergo profound morphological changes. The induced MSCs developed rounded cell bodies with multiple neurite-like extensions. Eventually they developed processes that formed networks reminiscent of primary cultures of neurons. Salvia mihiorrhiza and β-mercaptoethanol also induced MSCs to express nestin, β-tubulin Ⅲ, neurofilament （NF） and glial fibrillary acidic protein （GFAP）. It was confirmed by RT-PCR that MSCs could express pleiotrophin both before and after induction by Salvia miltiorrhiza. The expression was markedly enhanced after induction and the nestin gene was also expressed.Conclusions MSCs could be isolated from human umbilical cord Wharto
文摘Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.
文摘AIM:The prognosis of early gastric carcinoma (EGC) is generally excellent after surgery. The presence or absence of lymph node metastasis in EGC is an important prognostic factor. The survival and recurrence rates of node-negative EGC are much better than those of node-positive EGC. This study examined the factors related to lymph node metastasis in EGC to determine the appropriate treatment for EGC.METHODS: We investigated 748 patients with EGC who underwent surgery between January 1985 and December 1999 at the Division of Gastroenterologic Surgery, Department of Surgery, Chonnam National University Hospital. Several clinicopathologic factors were investigated to analyze their relationship to lymph node metastasis: age, sex, tumor location, tumor size, gross type, histologic type, depth of invasion, extent of lymph node dissection, type of operation,and DNA ploidy.RESULTS:Lymph node metastases were found in 75 patients (10.0%). Univariate analysis showed that male sex, tumor size larger than 2.0cm, submucosal invasion of tumor, histologic differentiation, and DNA ploidy pattern were risk factors for regional lymph node metastasis in EGC patients. However, a multivariate analysis showed that three risk factors were associated with lymph node metastasis:large tumor size, undifferentiated histologic type and submucosal invasion. No statistical relationship was found for age, sex, tumor location, gross type, or DNA ploidy in multivariate analysis. The 5-year survival rate was 94.2% for those without lymph node metastasis and 87.3% for those with lymph node metastasis, and the difference was significant (P<0.05).CONCLUSION: In patients with EGC, the survival rate of patients with positive lymph nodes is significantly worse than that of patients with no lymph node metastasis. Therefore,a standard D2 lymphadenectomy should be performed in patients at high risk of lymph node metastasis: large tumor size, undifferentiated histologic type and submucosal invasion.
