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991.
Timothy Turnert Philip Chen Lyndon J. Goodly Alan NWells 《Clinical & experimental metastasis》1996,14(4):409-418
Carcinomas of the prostate and other lineages often present an autocrine stimulatory loop acting via the EGF receptor (EGFR). We have recently shown that EGFR-mediated signals enhance DU-145 prostate carcinoma cell transmigration of an extracellular matrix in vitro, and that this increased invasiveness was independent of proteolytic degradation of the matrix (Xie et al., 1995, Clin Exp Metastasis, 13, 407). To determine whether up-regulated EGFR signaling promotes tumor progression in vivo and to define the EGFR-induced cell property responsible, we inoculated athymic mice with genetically-engineered DU-145 cells. Parental DU-145 cells and those transduced to overexpress a full-length wild type (WT) EGFR formed tumors and metastasized to the lung when inoculated in the prostate and peritoneal cavity. The WT DU-145 tumors were more invasive. DU-145 cells expressing a mitogenically-active, but motility-deficient (c'973) EGFR formed small, non-invasive tumors without evidence of metastasis. All three sublines demonstrated identical, EGFR-dependent rates of cell growth in vitro, suggesting that the differential invasiveness was not due to altered growth rates. To determine whether cell motility may be, in part, responsible for tumor invasiveness, we treated WT DU-145 intraperitoneal tumors with a pharmacologic agent (U73122) which blocks EGFR-mediated cell motility but not mitogenesis. Under this treatment regimen, the WT DU-145 cells formed tumors of similar numbers and size to those formed without treatment; however, these tumors were much less invasive. These data suggest that EGFR-mediated cell motility is an important mechanism involved in tumor progression, and that this cell property may represent a novel target to limit the spread of tumors. 相似文献
992.
The retrotrapezoid nucleus (RTN), a part of the rostral ventrolateral medulla, is involved in the control of breathing. The mechanisms by which the RTN modulate the activity of respiratory neurons during chemoreceptor stimulation are not fully understood. This electrophysiological study performed in the cat demonstrates that 18 out of 22 RTN neurons receive inputs from the commissural subnucleus of the solitary tract (cNTS), the peripheral chemoreceptor afferents projection site. Moreover, six RTN neurons are found to present interconnection between RTN and the ventrolateral subnucleus of the solitary tract, an area containing mainly bulbo-spinal respiratory neurons. The present data suggest that RTN play a key role by concomitantly integrating chemosensitive informations relayed by the cNTS and providing an influence on the respiratory network. 相似文献
993.
994.
995.
The effect of treatment with the cholecystokinin antagonist L364,718 on intake of different dilutions of corn oil emulsion was tested under two levels of familiarity with the oil emulsion. No increase in intake was observed. To see if the CCK antagonist was effective under our conditions, exogenous CCK was administered under the same conditions. A complete suppression of the large reduction produced by CCK on intake was found. 相似文献
996.
用形态计量的方法对老年(30个月)和成年(17个月)大鼠脑(Golgi染色标本)的海马CA3区锥体细胞的树突分支进行分级计数和测量了终末支的长度。结果是CA3神经元基树突和顶树突共有9级分支,衰老时第4级和第9级分支有显著的增多(P<0.02,P<0.03)。基树突终末支的长度衰老时无明显改变,顶树突终末支长度较成年组增加(P<0.05)。提示衰老时海马神经元的树突仍具有一定的增生和分化能力。这可能是对神经元退变的一种代偿机制。 相似文献
997.
Sun JS Lin FH Tsuang YH Chen LT Hong RC Chang WH Liu HC 《Journal of biomedical materials research》2000,52(3):509-516
Cytokines produced by macrophages in the periprosthetic membranes surrounding joint replacements have been implicated as causal agents in osteolysis and prosthetic loosening. The present study characterizes the response of human peripheral blood monocytes to titanium particles. Monocytes were obtained from donated blood and were cultured in the presence of different-sized titanium particles. Exposure to titanium-aluminum-vanadium particles significantly changed the release of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 (IL-1), whereas there was no significant effect on the release of prostaglandin E(2) (PGE(2)). When monocytes were cultured with particles, the titanium alloy particles induced significantly more release of TNF-alpha and less IL-1 secretion. Ciprofloxacin inhibited production of TNF-alpha, IL-6, IL-1, and PGE(2) in human monocytes exposed to titanium particles. In contrast to ciprofloxacin, indomethacin was not a potent inhibitor of TNF-alpha production but potentiated IL-6 production in titanium-stimulated monocytes. Indomethacin had no effect on the production of IL-1 and was a potent inhibitor of PGE(2) production in titanium-stimulated monocytes. Pentoxifylline had an inhibitor effect on TNF-alpha production in titanium-stimulated monocytes. Pentoxifylline potentiated IL-6 and IL-1 production in monocytes exposed to titanium particles and had a biphasic effect on the PGE(2) production. The results of this study support our hypothesis that human monocytes release bone resorption mediators after in vitro exposure to TiAlV alloy particles. The results also demonstrate the differences of bone-resorbing mediators in response to different wear particle size. The pharmacologic agents (ciprofloxacin, pentoxifylline, and indomethacin) that can modulate the release of bone resorbing mediators such as PGE(2), TNF-alpha, IL-1, and IL-6 release from human monocytes. The results help to elucidate the differences in cellular response to wear particles but may not be directly transposed to the human situation. 相似文献
998.
MTEC 1分泌的趋化因子引起特定亚群胸腺细胞的定向迁移 总被引:9,自引:0,他引:9
分析胸腺髓质上皮样细胞系MTEC1分泌的化学趋化因子对胸腺细胞亚群的趋化作用。方法以抗体加补体杀伤结合免疫磁珠及panning法,将小鼠胸腺细胞分离纯化,获得CD4+CD8+(DP),CD4-CD8-(DN),CD4+CD8-(CD4SP)及CD4-CD8+(CD8SP)四亚群细胞,用Boyden小室分析MTEC1┐SN对四群胸腺细胞的趋化作用。结果MTEC1┐SN对DP及CD4SP胸腺细胞有趋化活性(CI=6.6±1.0及6.1±1.8);对CD8SP细胞有中度趋化活性(CI=3.2±1.0);对DN趋化活性微弱(CI=1.3±0.6)。化学趋化因子MCP┐1纯品对CD4SP胸腺细胞显示强趋化活性(CI=5.6),对DN胸腺细胞则无可测出趋化活性。结论MTEC1分泌的化学趋化因子对DP,CD4SP及CD8SP胸腺细胞有显著趋化作用,对DN胸腺细胞几乎无趋化作用。提示此类化学趋化因子有趋使胸腺发育中后期阶段的细胞向胸腺髓质区迁移和定位的作用。 相似文献
999.
系统性红斑狼疮临床特征与HLA—DR,DQ基因的相关研究 总被引:2,自引:0,他引:2
采用聚合酶链反应结合顺序特异物寡核苷酸(PCR/SSO)探针杂交方法对HLA-DR,DQ亚区作DNA分型,分析了系统性红斑狼疮(SLE)的各种临床特征与HLA-DR、DQ基因的关联,结果发现汉族SLE中肾脏损害与DR2相关,而与DR4呈负相关,口、鼻腔粘膜溃疡与DR12相关,未发现SLE的其他临床特征与DR、DQ基因有关,发病年龄小于35a者,DR2,DQ6阳性率高,而DR3则多见于发病年龄大于3 相似文献
1000.