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T. S. King S. Steinlechner R. W. Steger 《Cellular and molecular life sciences : CMLS》1985,41(3):417-419
Summary Rates of 5-hydroxytryptamine (5-HT) turnover in the mediobasal hypothalamus of male rats were estimated using pharmacological methods during the daytime and at night. Concentrations of 5-HT in this hypothalamic area were higher nocturnally than diurnally; this was apparently due to increased 5-HT synthesis and decreased 5-HT catabolism at night.Supported by NIH grant RR07187 (TSK) and NIH grant HD10202 (Neuroendocrine Core). 相似文献
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Cell-fate conversion of lymphoid-committed progenitors by instructive actions of cytokines 总被引:33,自引:0,他引:33
Kondo M Scherer DC Miyamoto T King AG Akashi K Sugamura K Weissman IL 《Nature》2000,407(6802):383-386
The primary role of cytokines in haemato-lymphopoiesis is thought to be the regulation of cell growth and survival. But the instructive action of cytokines in haematopoiesis has not been well addressed. Here we show that a clonogenic common lymphoid progenitor, a bone marrow-resident cell that gives rise exclusively to lymphocytes (T, B and natural killer cells), can be redirected to the myeloid lineage by stimulation through exogenously expressed interleukin (IL)-2 and GM-CSF (granulocyte/macrophage colony-stimulating factor) receptors. Analysis of mutants of the beta-chain of the IL-2 receptor revealed that the granulocyte- and monocyte-differentiation signals are triggered by different cytoplasmic domains, showing that the signalling pathway(s) responsible for these unique developmental outcomes are separable. Finally, we show that the endogenous myelomonocytic cytokine receptors for GM-CSF and macrophage colony-stimulating factor (M-CSF) are expressed at low to moderate levels on the more primitive haematopoietic stem cells, are absent on common lymphoid progenitors, and are upregulated after myeloid lineage induction by IL-2. We conclude that cytokine signalling can regulate cell-fate decisions and propose that a critical step in lymphoid commitment is downregulation of cytokine receptors that drive myeloid cell development. 相似文献
197.
Mutations in COL11A2 cause non-syndromic hearing loss (DFNA13) 总被引:13,自引:0,他引:13
McGuirt WT Prasad SD Griffith AJ Kunst HP Green GE Shpargel KB Runge C Huybrechts C Mueller RF Lynch E King MC Brunner HG Cremers CW Takanosu M Li SW Arita M Mayne R Prockop DJ Van Camp G Smith RJ 《Nature genetics》1999,23(4):413-419
We report that mutation of COL11A2 causes deafness previously mapped to the DFNA13 locus on chromosome 6p. We found two families (one American and one Dutch) with autosomal dominant, non-syndromic hearing loss to have mutations in COL11A2 that are predicted to affect the triple-helix domain of the collagen protein. In both families, deafness is non-progressive and predominantly affects middle frequencies. Mice with a targeted disruption of Col11a2 also were shown to have hearing loss. Electron microscopy of the tectorial membrane of these mice revealed loss of organization of the collagen fibrils. Our findings revealed a unique ultrastructural malformation of inner-ear architecture associated with non-syndromic hearing loss, and suggest that tectorial membrane abnormalities may be one aetiology of sensorineural hearing loss primarily affecting the mid-frequencies. 相似文献
198.
Crow YJ Leitch A Hayward BE Garner A Parmar R Griffith E Ali M Semple C Aicardi J Babul-Hirji R Baumann C Baxter P Bertini E Chandler KE Chitayat D Cau D Déry C Fazzi E Goizet C King MD Klepper J Lacombe D Lanzi G Lyall H Martínez-Frías ML Mathieu M McKeown C Monier A Oade Y Quarrell OW Rittey CD Rogers RC Sanchis A Stephenson JB Tacke U Till M Tolmie JL Tomlin P Voit T Weschke B Woods CG Lebon P Bonthron DT Ponting CP Jackson AP 《Nature genetics》2006,38(8):910-916
Aicardi-Goutières syndrome (AGS) is an autosomal recessive neurological disorder, the clinical and immunological features of which parallel those of congenital viral infection. Here we define the composition of the human ribonuclease H2 enzyme complex and show that AGS can result from mutations in the genes encoding any one of its three subunits. Our findings demonstrate a role for ribonuclease H in human neurological disease and suggest an unanticipated relationship between ribonuclease H2 and the antiviral immune response that warrants further investigation. 相似文献
199.
提出的节理岩体剪切强度准则,考虑了节理面、岩桥提供的强度分量和相邻节理面形成的起伏角提供的强度分量。讨论了节理面和节理岩体发生剪切破坏时某些关键应力状态必须满足的物理约束条件。此外,强度准则中的参数可以是随机变量,所以可以用于随机模型中的破坏概率分析和工程的风险分析。 相似文献
200.
Sackett CA Kielpinski D King BE Langer C Meyer V Myatt CJ Rowe M Turchette QA Itano WM Wineland DJ Monroe C 《Nature》2000,404(6775):256-259
Quantum mechanics allows for many-particle wavefunctions that cannot be factorized into a product of single-particle wavefunctions, even when the constituent particles are entirely distinct. Such 'entangled' states explicitly demonstrate the non-local character of quantum theory, having potential applications in high-precision spectroscopy, quantum communication, cryptography and computation. In general, the more particles that can be entangled, the more clearly nonclassical effects are exhibited--and the more useful the states are for quantum applications. Here we implement a recently proposed entanglement technique to generate entangled states of two and four trapped ions. Coupling between the ions is provided through their collective motional degrees of freedom, but actual motional excitation is minimized. Entanglement is achieved using a single laser pulse, and the method can in principle be applied to any number of ions. 相似文献