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排序方式: 共有285条查询结果,搜索用时 15 毫秒
221.
Persistence of human multilineage, self-renewing lymphohematopoietic stem cells in chimeric sheep 总被引:1,自引:1,他引:1
Srour EF; Zanjani ED; Cornetta K; Traycoff CM; Flake AW; Hedrick M; Brandt JE; Leemhuis T; Hoffman R 《Blood》1993,82(11):3333-3342
We have previously reported the ability of uncharacterized human bone marrow (BM) cells to engraft into preimmune fetal sheep, thereby creating sheep-human chimera suitable for in vivo examination of the properties of human hematopoietic stem cells (HSC). Adult human bone marrow CD34+ HLA-DR- cells have been extensively characterized in vitro and have been demonstrated to contain a number of primitive hematopoietic progenitor cells (PHPC). However, the capacity of such highly purified populations of human marrow CD34+ HLA-DR- cells to undergo in vivo self-renewal and multipotential lymphohematopoietic differentiation has not been previously demonstrated. To achieve that, human CD34+ HLA-DR- cells were transplanted in utero into immunoincompetent fetal sheep to investigate the BM-populating potential of these cells. Long-term chimerism, sustained human hematopoiesis, and expression of human cells belonging to all human blood cell lineages were demonstrated in two animals for more than 7 months' posttransplantation. Chimeric BM contained erythroid, granulocytic/monocytic, and megakaryocytic hematopoietic progenitor cells, as well as the primitive high proliferative potential colony- forming cell (HPP-CFC). Under a variety of in vitro experimental conditions, chimeric BM cells gave rise to human T cells expressing T- lymphocyte-specific markers, human natural killer (NK) cells, and human IgG-producing B cells. In vivo expansion and possibly self-renewal of transplanted PHPC was confirmed by the detection in chimeric BM 130 days' posttransplantation of CD34+ HLA-DR- cells, the phenotype of human cells constituting the stem-cell graft. These studies demonstrate not only the BM-populating capacity, multipotential differentiation, and most likely self-renewal capabilities of human CD34+ HLA-DR- cells, but also that this BM population contains human HSC. Furthermore, it appears that this animal model of xenogeneic stem-cell transplantation is extremely useful for in vivo examination of human hematopoiesis and the behavioral and functional characteristics of human HSC. 相似文献
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Diana R. Keatinge RN RSCN M ADMIN PhD Michael Tarren-Sweeney BA GRAD DIP EPID Graham Vimpani MBBS PHD FRACP FAFPHM Philip Hazell MB CHB PhD FRANZCP Ken Callan B ED STUD M PSYCH 《Nursing & health sciences》2000,2(4):179-189
Abstract A recent study used both qualitative and quantitative methods to examine families' perceptions of service needs for children with disruptive behavior problems. Focusing on the qualitative component of the study, the present paper discusses the modified Nominal Group Technique used in focus groups attended by carers living in rural, regional or metropolitan contexts. Three questions posed to each focus group sought to identify families' concerns about health facilities and/or related support services currently available to them, the benefits they perceived in these services and the changes needed to make these services more appropriate or accessible to them. Major themes in the responses relating to each of these questions included concerns about a lack of, or perceived need for, access to help/support, benefits in schools that accommodated the needs of the children, and support from the community. Families' recommendations for change included increased access to health care advice, information and/or support systems. 相似文献
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背景:半髋和全髋关节置换术常用于治疗囊内移位性的股骨颈骨折,但是每一种方法都有缺点,对这些骨折的最佳治疗方法仍存在争议。方法:前瞻性随机研究,对81例移位性术前可活动并生活独立的股骨颈骨折患者,随机行全髋或半髋关节置换术。患者平均年龄75岁。结果采用Oxford髋关节评分来评价,并对最近的X线片作评估。结果:平均随访3年,半髋关节置换组平均行走距离为1.17英里(1.9km),全髋关节置换组平均行走距离为2.23英里(3.6km);半髋关节置换组平均Oxford髋关节评分为22.3分,而全髋关节置换组平均Oxford髋关节评分为18.8分。全髋关节置换组患者较半髋关节置换组患者行走距离较远(p=O.039),Oxford髋关节评分较低(较好)(p=O.033)。32例生存的半髋关节置换患者中,有20例在最后随访时X线片上出现髋臼磨损表现。半髋关节置换组没有出现髋关节脱位,而全髋关节置换组发生3例脱位。在半髋关节置换组,2例翻修改行全髋关节置换,3例出现髋臼严重磨损须翻修。在全髋关节置换组,1例由于股骨假体下沉而作翻修。结论:在该前瞻性随机研究中,对在术前可活动并生活独立的囊内移位性股骨颈骨折患者,全髋关节置换较半髋关节置换具有较好的短期临床结果和更少的并发症。可信水平:治疗性研究,Ⅰ级。进一步可信度参见作者介绍。 相似文献