关于周人女始祖姜嫄的几个问题

后稷本是其母姜嫄参加社祭后与某个姬姓男子野合而生,而史籍载为“履大迹”、“履大人迹”、践“巨人迹”,完全是出于儒家崇圣心理而对野合的巧妙掩盖;为了更神异其事,乃曰“履帝迹耳”,因为当时尚无“帝”、“上帝”的概念。姜嫄生活的时代,相当于中国古史传说的尧、舜、禹时期。当时盛行普那路亚婚(即外婚制),民“知母不知父”,因而后稷被其母姜嫄抛弃,既不是因为他无父而生,也不是因为他要接受图腾仪式的考验,而是因为他出生时“胎生如卵”(带胞生),形体异常,古人以为妖异而不祥,所以被抛弃。

Fibroblast growth factor-4 and hepatocyte growth factor induce differentiation of human umbilical cord blood-derived mesenchymal stem cells into hepatocytes

AIM： To investigate the differentiation of human umbilical cord blood （HUCB）-derived mesenchymal stem cells （MSCs） into hepatocytes by induction of fibroblast growth factor-4 （FGF-4） and hepatocyte growth factor （HGF）, and to find a new source of cell types for therapies of hepatic diseases. METHODS： MSCs were isolated by combining gradient density centrifugation with plastic adherence. When HUCB-derived MSCs reached 70% confluence, they were cultured in Iscove modified Dulbecco medium （IMDM） supplemented with 10 mL/L FBS, 20 ng/mL HGF and 10 ng/mL FGF-4. The medium was changed every 4 d and stored for albumin, alpha-fetoprotein （AFP） and urea assay. Expression of CK-18 was detected by immunocytochemistry. Glycogen storage in hepatocytes was determined by PAS staining. RESULTS： By combining gradient density centrifugation with plastic adherence, we could isolate MSCs from 25.6% of human umbilical cord blood. When MSCs were cultured with FGF-4 and HGF, approximately 63.6% of cells became small, round and epithelioid on d 28 by morphology. Compared with the control, the level of AFP increased significantly from d 12 to 18.20：1=1.16 μg/L （t = 2.884, P〈0.05） in MSCs cultured with FGF-4 and HGF, and was higher （54.28±3.11 μg/L） on d 28 （t = 13.493, P〈0.01）. Albumin increased significantly on d 16 （t = 6.68, P〈0.01） to 1.02±0.15 μg/mL, and to 3.63±0.30 μg/mL on d 28 （t = 11.748, P〈0.01）. Urea （4.72±1.03 μmol/L） was detected on d 20 （t = 4.272, P〈0.01）, and continued to increase to 10.28±1.06 μmol/L on d 28 （t = 9.276, P〈0.01）. Cells expressed CK-18 on d 16. Glycogen storage was observed on d 24. CONCLUSION： HUCB-derived MSCs can differentiate into hepatocytes by induction of F-GF-4 and HGF. HUCB derived MSCs are a new source of cell types for cell transplantation therapy of hepatic diseases.

Expression of Caspase－3 in Cord Blood CD34^＋ Cells during Culture in vitro

Objective: To investigate the expression and significance of caspase-3 protein in CD34^+ cells from cord blood (CB) during culture in vitro with different growth factors. Methods: RT-PCR, Western blot and flow cytometry techniques were used to detect the expression of caspase-3 in CD34^+ CB cells during culture in vitro. Results: Caspase-3 mRNA was constitutively expressed at a low level in freshly isolated CD34^+ cells. The expression of caspase-3 mRNA and protein was upregulated when these cellswere first expanded in suspension culture with growth factors for 3 days. However, only the 32 kDa inactive caspase-3 proenzyme was detected in the freshly isolated CD34^+ cells as well as during the first 3 days expansion with cytokines. With longer culture time in vitro, especially in the presence of the combination of IL-3, IL-6 and GM-CSF, caspase-3 was activated and a cleavage product of 20 kDa became detectable.Conclusion: Caspase-3 is involved in apoptosis of primitive CB CD34^+ cells during expansion in vitro.

Transplantation of microencapsulated umbilical-cord-blood-derived hepatic-like cells for treatment of hepatic failure

AIM: To investigate intraperitoneal transplantation of microencapsulated hepatic-like cells from human umbilical cord blood for treatment of hepatic failure in rats. METHODS: CD34+ cells in umbilical cord blood cells were isolated by magnetic cell sorting. In the in vitro experiment, sorted CD34+ cells were amplified and induced into hepatic-like cells by culturing with a combination of fibroblast growth factor 4 and hepatocyte growth factor. Cultures without growth factor addition served as controls. mRNA and protein levels for hepatic-like cells were analyzed by reverse transcription-polymerase chain reaction, immunohistochemistry and immunofluorescence. In the in vivo experiment, the hepatic-like cells were encapsulated and transplanted into the abdominal cavity of acute hepatic failure (AHF) rats at 48 h after D-galactosamine induction of acute hepatic failure. Transplantation with PBS and unencapsulated hepatic-like cells served as controls. The mortality rate, hepatic pathological changes and serum biochemical indexes were determined. The morphology and structure of microcapsules in the greater omentum were observed. RESULTS: Human albumin, alpha-fetoprotein and GATA-4 mRNA and albumin protein positive cells were found among cultured cells after 16 d. Albumin level in culture medium was significantly increased after culturing with growth factors in comparison with culturing without growth factor addition (P < 0.01). Compared with the unencapsulated group, the mortality rate of the encapsulated hepatic-like cell-transplanted group was significantly lower (P < 0.05). Serum biochemical parameters, alanine aminotransferase, aspartate aminotransferase and total bilirubin in the encapsulated group were significantly improvement compared with the PBS control group (P < 0.01). Pathological staining further supported these findings. At 1-2 wk post-transplantation, free microcapsules with a round clear structure and a smooth surface were observed in peritoneal lavage fluid, surviving cells inside microcapsules were found by trypan blue staining, but some fibrous tissue around microcapsules was also detected in the greater omentum of encapsulated group by hematoxylin and eosin staining. CONCLUSION: Transplantation of microencapsulated hepatic-like cells derived from umbilical cord blood cells could preliminarily alleviate the symptoms of AHF rats.