Nature vol.460 (7252), (9 Jul 2009) # D- O1 ~6 |* s
脂肪细胞对造血作用的影响 ; U& C% V8 R( ?9 a0 v1 C+ s成年骨髓含有众多脂肪细胞，其数量与造血活性成反比关系。造血作用过剩类疾病如恶性贫血和白血病等，一般都伴随着造血作用对长骨脂髓的渗透。至于脂肪细胞是参与造血调控、还是只是扩张来填满骨髓空间一直不清楚。答案似乎是，脂肪细胞远不止是充数，而是在骨髓微环境中起一个非常关键的生理作用。用小鼠所做实验表明，脂肪细胞数量多的骨髓所含造血干细胞和祖细胞要少于脂肪细胞数量少的骨髓。遗传上不含脂肪细胞的小鼠和用一种阻断脂肪细胞产生的药物处理过的小鼠，在经过一次骨髓移植之后产生新的血细胞的速度要比野生型小鼠快，说明阻断骨髓脂肪细胞生成在临床骨髓移植中也许可帮助造血作用的恢复。 # A x/ b3 n- P" d+ u: C( }2 x( M% W7 a. b& z' H
Letters to Nature p.259 " H- N5 g/ e$ P . e; x0 }7 A! L# k8 W% Ndoi:10.1038/nature08099 2 B: B6 N q; Z- h1 e http://www.nature.com/nature/jou ... bs/nature08099.html作者: 不帅的男孩 时间: 2009-8-1 12:11
Science 10 July 2009: & e! f6 E v1 h r0 OVol. 325. no. 5937, pp. 167 - 171 - c1 ~! w: z" S7 R, r6 O1 iDOI: 10.1126/science.1174294- |) a; c) Q! `* `# v
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Research Articles5 M% X2 w) p7 Y) E& H. }
Cell Growth and Size Homeostasis in Proliferating Animal Cells% O3 p4 h2 B5 a0 m1 ~ U4 H; V
Amit Tzur,1,* Ran Kafri,1,* Valerie S. LeBleu,2 Galit Lahav,1 Marc W. Kirschner1, : g& I: m5 y9 m: A
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A long-standing question in biology is whether there is an intrinsic mechanism for coordinating growth and the cell cycle in metazoan cells. We examined cell size distributions in populations of lymphoblasts and applied a mathematical analysis to calculate how growth rates vary with both cell size and the cell cycle. Our results show that growth rate is size-dependent throughout the cell cycle. After initial growth suppression, there is a rapid increase in growth rate during the G1 phase, followed by a period of constant exponential growth. The probability of cell division varies independently with cell size and cell age. We conclude that proliferating mammalian cells have an intrinsic mechanism that maintains cell size. 2 v, H2 T2 v3 G http://www.sciencemag.org/cgi/content/abstract/325/5937/167作者: 不帅的男孩 时间: 2009-8-1 12:11
Science 10 July 2009: 5 a0 `0 T3 e& w( \" xVol. 325. no. 5937, pp. 217 - 218 - z! ?* b$ D ]* I8 j6 Y/ lDOI: 10.1126/science.1171461 i% `% a# {6 D, }" D( Q8 GPrev | Table of Contents | Next ; ]* H" G1 o0 r* b- W. _8 K 8 T7 ~+ G( x! DReports 9 d" H: l+ G# ~& cHematopoietic Cytokines Can Instruct Lineage Choice , v. S5 I; m4 ~% j' L* {Michael A. Rieger, Philipp S. Hoppe, Benjamin M. Smejkal, Andrea C. Eitelhuber, Timm Schroeder* * \; t/ Q% p" |4 [ + U7 X& G( ~" P1 T" F( oThe constant regeneration of the blood system during hematopoiesis requires tightly controlled lineage decisions of hematopoietic progenitor cells (HPCs). Because of technical limitations, differentiation of individual HPCs could not previously be analyzed continuously. It was therefore disputed whether cell-extrinsic cytokines can instruct HPC lineage choice or only allow survival of cells that are already lineage-restricted. Here, we used bioimaging approaches that allow the continuous long-term observation of individual differentiating mouse HPCs. We demonstrate that the physiological cytokines, macrophage colony-stimulating factor and granulocyte colony-stimulating factor, can instruct hematopoietic lineage choice. # ~6 |" Y/ A. q1 o% }http://www.sciencemag.org/cgi/content/abstract/325/5937/217作者: niyou 时间: 2009-8-1 12:53