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排序方式: 共有102条查询结果,搜索用时 15 毫秒
21.
Cai XJ Denis R Vernon RG Clapham JC Wilson S Arch JR Williams G 《Regulatory peptides》2001,97(2-3):163-168
Orexins are hypothalamic peptides implicated in the regulation of ingestive and other behaviours. Here we investigated prepro-orexin expression and hypothalamic orexin-A and -B levels in lactating rats, which display marked hyperphagia, with or without food restriction for 2 days or treatment with bromocriptine, which inhibits milk production and thus reduces the energy losses of lactation. Neither prepro-orexin gene expression nor hypothalamic orexin-A peptide levels were changed in any of these lactating groups compared with age-matched virgin controls. However, hypothalamic orexin-B levels were significantly higher in lactating rats that were food-restricted for 2 days (P<0.05) compared with non-lactating controls and with lactating rats that were either freely-fed or bromocriptine-treated. Thus, food restriction superimposed on lactation selectively increases hypothalamic orexin-B levels, suggesting that orexin-A and -B may be differentially released or cleared. Changes in orexin-B availability may influence physiological activities other than energy homeostasis, perhaps inducing arousal. 相似文献
22.
Glucocorticoid-induced TNF receptor functions as a costimulatory receptor that promotes survival in early phases of T cell activation 总被引:2,自引:0,他引:2
Glucocorticoid-induced TNFR (GITR) is a member of the TNFR family that can inhibit the suppressive function of regulatory T cells and promote the survival and activation of T cells. However, little is known about the molecular mechanisms regulating T cell survival and activation downstream of GITR. To gain further insight into the cellular events and signaling pathways triggered by GITR, survival, proliferation, and cytokine production as well as activation of MAPKs and NF-kappaB were monitored after cross-linking of the receptor on naive and activated T cells. GITR cross-linking provided costimulation of naive and activated T cells and resulted in activation of MAPKs and NF-kappaB. Although GITR-induced signaling pathways augmented the survival of naive T cells, they were not sufficient to inhibit activation-induced cell death triggered by CD3 cross-linking of activated T cells. Differences in the contributions of GITR to cell survival between naive and activated T cells suggest that the receptor triggers specific pathways depending on the activation state of the T cell. 相似文献
23.
Chezian Somasundaram Robert Arch Siegfried Matzku Margot Zöller 《Cancer immunology, immunotherapy : CII》1996,42(6):343-350
A bispecific F(ab′)2 antibody conjugate (BAC) was constructed against the complement receptor CR3 of macrophages and a variant CD44 (CD44v6) antigen
of rat pancreatic adenocarcinoma cells to redirect macrophage-mediated tumor cytotoxicity. The Fab′ fragments of monoclonal
antibodies (mAb) 1.1ASML and OX42, recognizing the CD44v6 and the CR3 antigens respectively, were chemically coupled at the
hinge region using 5,5′-dithiobis(2-nitrobenzoate). The BAC was characterized in vitro for its specific, dual binding capacity
to CD44v6 and CR3 antigens. Although the monovalence of the BAC resulted in lower avidities to both the antigens as expected,
it was still able to form stable cross-linkages between tumor cells and macrophages in culture leading to the formation of
“clump-like” cell aggregates. The in vitro and in vivo tumor-targeting capacity of the BAC was compared with that of the parental
antitumor mAb 1.1ASML, which mediates tumor killing by antibody-dependent cell cytotoxicity. These results showed that, even
though the bivalent mAb 1.1ASML did not mediate stable cross-linking of target and effector cells, its Fc-receptor-mediated
killing of tumor cells was more effective when compared to the BAC. Thus, this study strongly supports the hypothesis that
firm persistent binding between effector and target cells per se is not as important as the choice of trigger molecule used for macrophage activation to redirect their tumor cytotoxic potential
effectively.
Received: 2 May 1996 / Accepted: 21 May 1996 相似文献
24.
Esparza EM Lindsten T Stockhausen JM Arch RH 《The Journal of biological chemistry》2006,281(13):8559-8564
Tumor necrosis factor receptor (TNFR) family members such as glucocorticoid-induced TNFR (GITR) control T cell activation, differentiation, and effector functions. Importantly, GITR functions as a pivotal regulator of physiologic and pathologic immune responses by abrogating the suppressive effects of T regulatory cells and costimulating T effector cells. However, the molecular mechanisms underlying GITR-triggered signal transduction pathways remain unclear. Interestingly, GITR-induced stimulation of TNFR-associated factor (TRAF) 5-deficient T cells resulted in decreased activation of nuclear factor kappaB as well as the mitogen-activated protein kinases p38 and extracellular signal-regulated protein kinase, whereas activation of c-Jun N-terminal kinase was less affected. Consistent with impaired signaling, costimulatory effects of GITR were diminished in TRAF5-/- T cells. In sum, our studies indicate that TRAF5 plays a crucial role in GITR-induced signaling pathways that augment T cell activation. 相似文献
25.
The lateral hypothalamic area (LHA), a key site involved in the central control of feeding and energy homeostasis, contains populations of neurons that produce the orexin peptides or nitric oxide, two chemical factors that increase food intake. In this study, we used immunohistochemistry to investigate the possibility that rat LHA neurons co-express orexin-A and neuronal nitric oxide synthase (nNOS). The orexin-A and nNOS cell populations in the LHA showed extensive overlap without co-localization, and no evidence of direct anatomic contact was found. The finding that LHA neurons do not co-localize orexin-A and nNOS may suggest that the actions of the orexins and nitric oxide on food intake are mediated via independent mechanisms, however, nitric oxide is a diffusible molecule and could potentially affect the activity of orexin neurons via a non-synaptic mechanism. 相似文献
26.
27.
Biosynthesis of the Egg-Laying Hormone (ELH) in the Bag Cell Neurons of Aplysia californica 总被引:5,自引:2,他引:5
S. Arch 《The Journal of general physiology》1972,60(1):102-119
Biosynthesis of the egg-laying hormone in the bag cell neurons of Aplysia californica was studied. Bag cells were incubated with leucine-3H in vitro for 30 min and rinsed for variable periods of time in a chase medium. The distribution of incorporated label among proteins within the cells was assayed by electrophoresis of an homogenate on sodium dodecyl sulfate polyacrylamide gels. Results from rinse times shorter than 30 min revealed that the predominant synthetic product is a 25,000 dalton protein. With longer rinse times, this species was reduced and two species of lower molecular weight became prominent. This redistribution of radioactivity was quantitative and was not prevented by inhibition of protein synthesis during the rinse. A 10°C reduction in temperature (from 15°C) blocked the redistribution. These data are interpreted to indicate that the 25,000 dalton molecule is a precursor which is cleaved enzymatically to yield two lower molecular weight products. One product is a 12,000 dalton molecule which remains in the cell bodies. The other is a molecule of <10,000 daltons which is exported from the somata into the neurohemal regions of the connective tissue. Perfusion of these regions with high [K+] medium results in the release of this product into the medium. It is concluded that this product is the 6000 dalton egg-laying hormone (ELH). 相似文献
28.
Y Deng J Zhao D Sakurai KM Kaufman JC Edberg RP Kimberly DL Kamen GS Gilkeson CO Jacob RH Scofield CD Langefeld JA Kelly ME Alarcón-Riquelme BIOLUPUS GENLES Networks JB Harley TJ Vyse BI Freedman PM Gaffney KM Sivils JA James TB Niewold RM Cantor W Chen BH Hahn EE Brown PROFILE BP Tsao 《Arthritis research & therapy》2012,14(Z3):A5
29.
Microorganisms are associated with a variety of ancient geological materials. However, conclusive proof that these organisms
are as old as the geological material and not more recent introductions has generally been lacking. Over the years, numerous
reports of the isolation of ancient bacteria from geological materials have appeared. Most of these have suffered from the
fact that the protocol for the surface sterilization of the sample was either poorly defined, inadequate or rarely included
data to validate the overall effectiveness of the sterilization protocol. With proper sterility validation and isolation protocol,
a legitimate claim for the isolation of an ancient microbe can be made. Biochemical, physiological, or morphological data
indicate that these ancient microbes are not significantly different from modern isolates. As the role (decomposition) of
modern and ancient microbes has not changed over time, it is probably unreasonable to expect these organisms to be vastly
different. A discussion on the reasons for the homogeneity of ancient and modern microbes is presented. Journal of Industrial Microbiology & Biotechnology (2002) 28, 32–41 DOI: 10.1038/sj/jim/7000174
Received 20 May 2001/ Accepted in revised form 16 June 2001 相似文献
30.
Architecture of epigenetic reprogramming following Twist1-mediated epithelial-mesenchymal transition
Gabriel G Malouf Joseph H Taube Yue Lu Tapasree Roysarkar Shoghag Panjarian Marcos RH Estecio Jaroslav Jelinek Jumpei Yamazaki Noel J-M Raynal Hai Long Tomomitsu Tahara Agata Tinnirello Priyanka Ramachandran Xiu-Ying Zhang Shoudan Liang Sendurai A Mani Jean-Pierre J Issa 《Genome biology》2013,14(12):R144