AIM: To determine whether diminished levels of epidermal growth factor (EGF) were present in neo-natal rats with intestinal injury and related with the degree of intestinal injury, so we modeled a model in neo-natal r...AIM: To determine whether diminished levels of epidermal growth factor (EGF) were present in neo-natal rats with intestinal injury and related with the degree of intestinal injury, so we modeled a model in neo-natal rats of intestinal injury and to examine the dynamic levels of EGF on injury of intestine.METHODS: One-day-old Wistar rat pups received an intraperitoneally injection with 4 mg/kg lipopolysaccharide (LPS), followed by collection of ileum tissue at 1, 3, 6, 12,and 24 h following LPS administration. The ileum was for histological evaluation of NEC and for measurements of EGF using ABC-ELISA. The correlation between the degree of intestinal injury and levels of EGF was determined. RESULTS: The LPS-injected pups also showed a significant increase in injury scores at 1, 3, 6, 12, and 24 h [respectively, (1.08±0.61), (1.63±0.84), (1.95±0.72), (2.42±0.43)and (2.21±0.53)] vsthe control (0.12±0.17) (P＜0.01).EGF levels at 1, 3, 6, 12 h [respectively, (245.6±49.0), (221.4±39.0), (223.4±48.1), (246.0±46.6)] pg/mg were significantly loss than the control (275.6±50.4) pg/mg (P＜0.05). There was a significant negative correlation between the EGF levels and the grade of intestinal injury within 24 h (P＜0.05).CONCLUSION: Neo-natal rats with intestinal injury have significantly lower levels of ileum EGF. Reduced levels of this growth factor might be related to the pathogenesis of NEC.展开更多
Based on the anatomical study of leaf cuticles of Cordaites from the Lower Permian Shanxi Formation in Baode of Shanxi, the author analysed the epidermal characters of Cordaites in this area. On the base of the abunda...Based on the anatomical study of leaf cuticles of Cordaites from the Lower Permian Shanxi Formation in Baode of Shanxi, the author analysed the epidermal characters of Cordaites in this area. On the base of the abundant compressions and laboratory studies, the author complemented some new data of the cuticular characters of the speeies Cordaites baodeensis Sun for its study of taxonomy. Meanwhile, the author newly discovered a number of sporopollen fossils associated with the mega-plants of Cordctitales, described 9 species of 6 genera. The palynological data can provide a supplement evidence for defining the age of C. baodeensis and its associated plants to be Early Permian.展开更多
The remarkable ability of rapid self-renewal makes the intestinal epithelium an ideal model for the study of adult stem cells. The intestinal epithelium is organized into villus and crypt, and a group of intestinal st...The remarkable ability of rapid self-renewal makes the intestinal epithelium an ideal model for the study of adult stem cells. The intestinal epithelium is organized into villus and crypt, and a group of intestinal stem cells located at the base of crypt are responsible for this constant self-renewal throughout the life. Identification of the intestinal stem cell marker Lgr5, isolation and in vitro culture of Lgr5+ intestinal stem cells and the use of transgenic mouse models have significantly facilitated the studies of intestinal stem cell homeostasis and differentiation, therefore greatly expanding our knowledge of the regulatory mechanisms underlying the intestinal stem cell fate determination. In this review, we summarize the current understanding of how signals of Wnt, BMP, Notch and EGF in the stem cell niche modulate the intestinal stem cell fate.展开更多
The genus Paliurus is characterized by its distinctive orbicular-winged fruits and a trilocular(or bilocular) ovary. Macrofossil records suggested this genus was distributed widely in North America, Europe, and Asia d...The genus Paliurus is characterized by its distinctive orbicular-winged fruits and a trilocular(or bilocular) ovary. Macrofossil records suggested this genus was distributed widely in North America, Europe, and Asia during the Paleogene and Neogene, before its present limitation to Eurasia. In this study, we describe some Paliurus fossil winged fruits from the lower part of Youganwo Formation(middle Eocene) and Huangniuling Formation(late Eocene) of the Maoming Basin, South China. These fruits are recognized as Paliurus favonii Unger based on a detailed study on the fossil morphology and cuticle characteristics. This represents the earliest occurrence of Paliurus fossil fruits in eastern Asia, and to date is the world's lowest latitude appearance for this genus. The most ancient records of Paliurus throughout the world are from the middle Eocene of North America and the late Eocene of Japan, leading some researchers to conclude the Paliurus may have originated in North America. Molecular data, however, do not support this hypothesis. The present Paliurus fossil fruits provide new evidence for the origin and phytogeographic history of this genus.展开更多
文摘AIM: To determine whether diminished levels of epidermal growth factor (EGF) were present in neo-natal rats with intestinal injury and related with the degree of intestinal injury, so we modeled a model in neo-natal rats of intestinal injury and to examine the dynamic levels of EGF on injury of intestine.METHODS: One-day-old Wistar rat pups received an intraperitoneally injection with 4 mg/kg lipopolysaccharide (LPS), followed by collection of ileum tissue at 1, 3, 6, 12,and 24 h following LPS administration. The ileum was for histological evaluation of NEC and for measurements of EGF using ABC-ELISA. The correlation between the degree of intestinal injury and levels of EGF was determined. RESULTS: The LPS-injected pups also showed a significant increase in injury scores at 1, 3, 6, 12, and 24 h [respectively, (1.08±0.61), (1.63±0.84), (1.95±0.72), (2.42±0.43)and (2.21±0.53)] vsthe control (0.12±0.17) (P＜0.01).EGF levels at 1, 3, 6, 12 h [respectively, (245.6±49.0), (221.4±39.0), (223.4±48.1), (246.0±46.6)] pg/mg were significantly loss than the control (275.6±50.4) pg/mg (P＜0.05). There was a significant negative correlation between the EGF levels and the grade of intestinal injury within 24 h (P＜0.05).CONCLUSION: Neo-natal rats with intestinal injury have significantly lower levels of ileum EGF. Reduced levels of this growth factor might be related to the pathogenesis of NEC.
基金Supported by Project"111"in Jilin University, China (No.B06008)
文摘Based on the anatomical study of leaf cuticles of Cordaites from the Lower Permian Shanxi Formation in Baode of Shanxi, the author analysed the epidermal characters of Cordaites in this area. On the base of the abundant compressions and laboratory studies, the author complemented some new data of the cuticular characters of the speeies Cordaites baodeensis Sun for its study of taxonomy. Meanwhile, the author newly discovered a number of sporopollen fossils associated with the mega-plants of Cordctitales, described 9 species of 6 genera. The palynological data can provide a supplement evidence for defining the age of C. baodeensis and its associated plants to be Early Permian.
基金supported by the National Natural Science Foundation of China(31330049,31221064)National Basic Research Program of China(2011CB943803,2011CBA01104,2010CB833706)to Chen Ye-Guang
文摘The remarkable ability of rapid self-renewal makes the intestinal epithelium an ideal model for the study of adult stem cells. The intestinal epithelium is organized into villus and crypt, and a group of intestinal stem cells located at the base of crypt are responsible for this constant self-renewal throughout the life. Identification of the intestinal stem cell marker Lgr5, isolation and in vitro culture of Lgr5+ intestinal stem cells and the use of transgenic mouse models have significantly facilitated the studies of intestinal stem cell homeostasis and differentiation, therefore greatly expanding our knowledge of the regulatory mechanisms underlying the intestinal stem cell fate determination. In this review, we summarize the current understanding of how signals of Wnt, BMP, Notch and EGF in the stem cell niche modulate the intestinal stem cell fate.
基金supported by the National Natural Science Foundation of China(Grant No.41210001)the Fundamental Research Funds for the Central Universities+2 种基金the Guangdong Provincial Natural Science Foundation of China(Grant No.10151027501000020)the Key Project of Sun Yat-sen University for inviting foreign teachersthe Scientific Research Fund,Hongda Zhang,Sun Yat-sen University
文摘The genus Paliurus is characterized by its distinctive orbicular-winged fruits and a trilocular(or bilocular) ovary. Macrofossil records suggested this genus was distributed widely in North America, Europe, and Asia during the Paleogene and Neogene, before its present limitation to Eurasia. In this study, we describe some Paliurus fossil winged fruits from the lower part of Youganwo Formation(middle Eocene) and Huangniuling Formation(late Eocene) of the Maoming Basin, South China. These fruits are recognized as Paliurus favonii Unger based on a detailed study on the fossil morphology and cuticle characteristics. This represents the earliest occurrence of Paliurus fossil fruits in eastern Asia, and to date is the world's lowest latitude appearance for this genus. The most ancient records of Paliurus throughout the world are from the middle Eocene of North America and the late Eocene of Japan, leading some researchers to conclude the Paliurus may have originated in North America. Molecular data, however, do not support this hypothesis. The present Paliurus fossil fruits provide new evidence for the origin and phytogeographic history of this genus.
