小鼠胚胎早期血细胞发生的研究进展

根据时空上的不同,小鼠胚胎发育时期的血细胞发生目前被分为原始造血、红系/髓系祖细胞（EMPs）的产生和造血干细胞（HSCs）成熟并分化为各种血细胞3个阶段。最新的观点也把原始造血和EMPs的产生归结为非HSCs依赖性的血细胞谱系分化阶段,将第3阶段称为HSCs依赖性的血细胞谱系分化阶段。尽管胚胎时期的血细胞发生涉及多个造血器官,但本文中我们主要对近年在细胞和分子水平进行的造血细胞和HSCs在卵黄囊和腹主动脉-性腺-中肾（AGM）区发育的研究进行归纳总结,以此展示新近发现的胚胎发育早期血细胞发生的特点及其潜在机制。     

MicroRNAs in hematological malignancies

MicroRNAs (miRNAs) have become one of the hottest topics in biology over recent years, but remarkably have only been formally recognized for just over 10 years. These endogenously produced short (19–24 nt) non-coding RNAs have introduced an entirely new paradigm in our understanding of gene control and it is now evident that miRNAs play a crucial regulatory role in many, if not all, physiological and pathological processes. In this review we provide an overview of the role and potential clinical utility for miRNAs in hematological malignancies and their function in normal hematopoiesis. Although still in its infancy, the miRNA field has already added much to our understanding of hematological processes, and provides us with novel tools as both biomarkers and therapeutic agents for hematological malignancies.     

The biology of stem cell factor,a new hematopietic growth factor involved in stem cell regulation

Summary Recently, a new hematopoietic growth factor, stem cell factor, the ligand for the c-kit-proto-oncogene, has been cloned. The gene for this factor or for its receptor are deleted in two well know series of mice mutants which display pleiotropic stem cell defects. Therefore, this factor supposedly plays an important role in stem cell biology. This paper reviews some of the elegant genetic work which led to the discovery of the factor and of its receptor, the biological effects that this factor exerts in the hematopoietic system in normal individuals and in patients with Diamond-Blackfan anemia and speculates on some of its potential clinical applications.     

Extramedullary hematopoiesis mimicking the appearance of carcinomatosis or peritoneal mesothelioma: Computed tomography demonstration

The computed tomographic (CT) appearance of extensive intra-abdominal extramedullary hematopoiesis is illustrated in a 51-year old woman with agnogenic myeloid metaplasia. The CT images closely simulate peritoneal carcinomatosis or peritoneal mesothelioma.     

Direct effects of 13-cis and all-trans retinoic acid on normal bone marrow (BM) progenitors: Comparative study on BM mononuclear cells and on isolated CD 34+ BM cells

Summary The effects of both 13-cis-and all-trans retinoic acid (RA) on colony formation of normal bone marrow (BM) progenitors were investigated in semi-solid (methylcellulose) assays, using either isolated CD 34+ cells or BM mononuclear cells. Single cell liquid cultures were performed to further discriminate between direct and indirect effects. RA action results in significant decrease of colony forming units (CFUs). This effect is more pronounced starting from CD 34+ progenitors than starting from total BM. This overall decrease in CFUs is due to selective inhibition of CFU-M (macrophage) and erythroid colonies (BFU-E). At the single cell level the CFU-M inhibition is confirmed with — in addition — a significant inhibition of CFU-GM (granulocyte-macrophage) and a marked stimulation of CFU-G(granulocyte)s. Both retinoids exert the above-mentioned effects. All-trans RA, however, is effective at a tenfold lower concentration (10^–7 M) than 13-cis RA (10^–6 M). Results on CD 34+ BM fractions (substantially reduced in accessory cells) demonstrate that the described effects can probably be attributed to the direct action of RA on these progenitors; single progenitor (CD 34+) cell liquid cultures further prove this point.     

Expression of interferon-γ and tumor necrosis factor-α in bone marrow T cells and their levels in bone marrow plasma in patients with aplastic anemia

Immune-mediated stem cell damage has been postulated to be responsible for disease initiation and progression in aplastic anemia (AA). It is hypothesized that T lymphocytes play a major role in destroying the bone marrow (BM) stem cells of AA patients by infiltrating the BM and secreting excessive levels of anti-hematopoietic cytokines, interferon-gamma (IFN-), and tumor necrosis factor-alpha (TNF-). We undertook this study to assess the pathogenic significance of anti-hematopoietic cytokines such as IFN- and TNF- in BM T cells and plasma of AA patients. Significantly elevated levels of IFN- and TNF- were found in the BM plasma of AA patients compared to controls (p=0.05 and 0.006, respectively). Intracellular IFN- and not TNF- in BM CD3⁺ T cells of AA patients was significantly higher compared to controls (p=0.04 and p=0.2, respectively). A follow-up analysis of expression of these cytokines in BM T cells and their levels in BM plasma in five AA patients before and 180 days (6 months) after antithymocyte globulin (ATG) and cyclosporin A (CsA) therapy showed a decline 180 days after therapy compared to pre-therapy. We thus conclude that increased production of both IFN- and TNF- in the BM may contribute to disease pathogenesis in AA and ATG therapy may induce hematological remission by suppressing the elevated levels of IFN- and TNF- in AA BM.