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571.
572.
Uptake of bacterial H3-DNA into fish embryos 总被引:1,自引:0,他引:1
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Christian Berger-Vachon Lionel Collet Neuroscience & Sensory Systems Laboratory 《系统仿真学报》2002,14(1):55-60
1 Introduction1 1.1 About Hearing Mechanisms The hearing function in human beings is something very specific and difficult to understand because it uses the brain highest functions. Basically, we can say (figure 1) that several stages are involved [1]: It is not easy to give a unique interpretation to each one of these stages, as most of the involved processes overlap at all levels. Nevertheless, as a brief summary, let us assume that [2]: l The ear transmits the air vibrations and transfor… 相似文献
576.
Niels Henrik Abel and solvable equations 总被引:1,自引:0,他引:1
Communicated by J. Lützen 相似文献
577.
Apoptotic cell-derived factors induce arginase II expression in murine macrophages by activating ERK5/CREB 总被引:1,自引:1,他引:0
Barra V Kuhn AM von Knethen A Weigert A Brüne B 《Cellular and molecular life sciences : CMLS》2011,68(10):1815-1827
Apoptotic cell (AC)-derived factors alter the physiology of macrophages (MΦs) towards a regulatory phenotype, characterized
by reduced nitric oxide (NO) production. Impaired NO formation in response to AC-conditioned medium (CM) was facilitated by
arginase II (ARG II) expression, which competes with inducible NO synthase for l-arginine. Here we explored signaling pathways allowing CM to upregulate ARG II in RAW264.7 MΦs. Sphingosine-1-phosphate (S1P)
was required and acted synergistically with a so far unidentified factor to elicit high ARG II expression. S1P activated S1P2, since S1P2 knockdown prevented ARG II upregulation. Furthermore, ERK5 knockdown attenuated CM-mediated ARG II protein induction. CREB
was implicated as shown by EMSA analysis and decoy-oligonucleotides scavenging CREB in RAW264.7 MΦs, which blocked ARG II
expression. We conclude that AC-derived S1P binds to S1P2 and acts synergistically with other factors to activate ERK5 and concomitantly CREB. This signaling cascade shapes an anti-inflammatory
MΦ phenotype by ARG II induction. 相似文献
578.
Spinal intercostal-phrenic reflexes 总被引:1,自引:0,他引:1
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Mature T cells can be functionally divided into two categories distinguished by surface expression of either CD4 or CD8, which in turn corresponds to restriction by and binding to class II or class I major histocompatibility complex proteins, respectively. CD8 can be expressed as a homodimer of the alpha-chain, or as a heterodimer of alpha- and beta-chains on human and mouse T cells, although most peripheral T cells seem to express CD8 alpha beta heterodimers exclusively (reviewed in ref. 9). Functional characterization of CD8 has focused primarily on the effect of the alpha-chain, which enhances or reconstitutes T-cell responses in homodimeric form and may play a specific role in thymic selection. In contrast, no role has been ascribed to CD8 beta or alpha beta heterodimers specifically. Here we show that CD8 alpha beta transfectants produce more interleukin-2 than CD8 alpha transfectants in response to specific stimuli. Increased interleukin-2 is also observed in cells expressing hybrid CD8 beta-alpha molecules (extracellular CD8 beta plus CD8 alpha transmembrane and cytoplasmic regions) on their surface. These results indicate that external portions of CD8 beta could be critical and that they may act independently of CD8 alpha in mediating their augmentation effect. 相似文献