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排序方式: 共有87条查询结果,搜索用时 46 毫秒
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本文通过建立图象分析方法对免疫组织化学反应结果进行定量,检测观察H-ras在口腔颊粘膜上皮在正常(N)、慢性炎症(IF)、癌旁上皮(EAC)和鳞癌(SCC)的变化过程中的表达并进行分析。结果显示H-ras在SCC组中,以中等分化的SCC无论是H-ras表达的量还是细胞阳性率都较高。此外,组织学观察显示,H-ras在处于分化末期但尚未角化的正常上皮细胞中有较高的表达。本文结果显示了H-ras的过表达与上皮细胞的会化程度密切相关。本研究还显示,所采用的阳性区域透光值、平均总透光值及阳性反应区域与阴性反应区域比值可靠并有相关性。这进一步说明了用免疫组化定量方法检测H-ras癌基因表达的精确和可靠性。 相似文献
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Isolation and characterization of plasma membrane-associated cortical granules from sea urchin eggs 总被引:9,自引:6,他引:3 下载免费PDF全文
Cortical granules, which are specialized secretory organelles found in ova of many organisms, have been isolated from the eggs of the sea urchins Arbacia punctulata and Strongylocentrtus pupuratus by a simple, rapid procedure. Electron micropscope examination of cortical granules prepared by this procedure reveals that they are tightly attached to large segments of the plasma membrane and its associated vitelline layer. Further evidence that he cortical granules were associated with these cell surface layers was obtained by (125)I-labeling techniques. The cortical granule preparations were found to be rich in proteoesterase, which was purified 32-fold over that detected in a crude homogenate. Similarly, the specific radioactivity of a (125)I-labeled, surface glycoprotein was increased 40-fold. These facts, coupled with electron microscope observations, indicate the isolation procedure yields a preparation in which both the cortical granules and the plasma membrane-vitelline layer are purified to the same extent. Gel electrophoresis of the membrane-associated cortical granule preparation reveals the presence of at least eight polypeptides. The major polypeptide, which is a glycotprotein of apparent mol wt of 100,000, contains most of the radioactivity introduced by (125)I-labeling of the intact eggs. Lysis of the cortical granules is observed under hypotonic conditions, or under isotonic conditions if Ca(2+) ion is present. When lysis is under isotonic conditions is induced by addition of Ca(2+) ion, the electron-dense contents of the granules remain insoluble. In contrast, hypotonic lysis results in release of the contents of the granule in a soluble form. However, in both cases the (125)I-labeled glycoprotein remains insoluble, presumably because it is a component of either the plasma membrane or the vitelline layer. All these findings indicate that, using this purified preparation, it should be possible to carry out in vitro studies to better define some of the initial, surface-related events observed in vivo upon fertilization. 相似文献
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Lectin-binding sites on the plasma membranes of rabbit spermatozoa: Changes in surface receptors during epididymal maturation and after ejaculation 总被引:7,自引:5,他引:2 下载免费PDF全文
GL Nicolson N Usui R Yanagimachi H Yanagimachi Smith JR 《The Journal of cell biology》1977,74(3):950-962
Modifications in rabbit sperm plasma membranes during epididymal passage and after ejaculation were investigated by used of three lectins: concanavalin A (Con A); Ricinus communis I (RCA(I)); and wheat germ agglutinin (WGA). During sperm passage from caput to cauda epididymis, agglutination by WGA drastically decreased, and agglutination by RCA(I) slightly decreased, although agglutination by Con A remained approximately unchanged. After ejaculation, spermatozoa were agglutinated to a similar degree or slightly less by Con A, WGA, and RCA(I), compared to cauda epididymal spermatozoa. Ultrastructural examination of sperm lectin-binding sites with ferritin- lectin conjugates revealed differences in the densities of lectin receptors in various sperm regions, and changes in the same regions during epididymal passage and after ejaculation. Ferritin-RCA(I) showed abrupt changes in lectin site densities between acrosomal and postacrosomal regions of sperm heads. The relative amounts of ferritin-RCA(I) bound to heads of caput epididymal or ejaculated spermatozoa. Tail regions were labeled by ferritin RCA(I) almost equally on caput and cauda epididymal spermatozoa, but the middle-piece region of ejaculated spermatozoa was slightly more densely labeled than the principal-piece region, and these two regions on ejaculated spermatozoa were labeled less than on caput and cuada epididymal spermatozoa. Ferritin-WGA densely labeled the acrosomal region of caput epididymal spermatozoa, although labeling of cauda epidiymal spermatozoa was relatively sparse except in the apical area of the acrosomal region. Ejaculated spermatozoa bound only a few molecules of ferritin-WGA, even at the highest conjugate concentrations used. Caput epididymal, but not cauda epididymal or ejaculated spermatozoa, bound ferritin-WGA in the tail regions. Dramatic differences in labeling densities during epididymal passage and after ejaculation were not found with ferritin-Con A. 相似文献
7.
Thomas D. Wright Christopher Raybuck Akshita Bhatt Darlene Monlish Suravi Chakrabarty Katy Wendekier Nathan Gartland Mohit Gupta Matthew E. Burow Patrick T. Flaherty Jane E. Cavanaugh 《Journal of cellular biochemistry》2020,121(2):1156-1168
Triple-negative breast cancers (TNBCs) represent 15% to 20% of all breast cancers and are often associated with poor prognosis. The lack of targeted therapies for TNBCs contributes to higher mortality rates. Aberrations in the phosphoinositide-3-kinase (PI3K) and mitogen-activated protein kinase pathways have been linked to increased breast cancer proliferation and survival. It has been proposed that these survival characteristics are enhanced through compensatory signaling and crosstalk mechanisms. While the crosstalk between PI3K and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways has been characterized in several systems, new evidence suggests that MEK5/ERK5 signaling is a key component in the proliferation and survival of several aggressive cancers. In this study, we examined the effects of dual inhibition of PI3K/protein kinase B (Akt) and MEK5/ERK5 in the MDA-MB-231, BT-549, and MDA-MB-468 TNBC cell lines. We used the Akt inhibitor ipatasertib, ERK5 inhibitors XMD8-92 and AX15836, and the novel MEK5 inhibitor SC-1-181 to investigate the effects of dual inhibition. Our results indicated that dual inhibition of PI3K/Akt and MEK5/ERK5 signaling was more effective at reducing the proliferation and survival of TNBCs than single inhibition of either pathway alone. In particular, a loss of Bad phosphorylation at two distinct sites was observed with dual inhibition. Furthermore, the inhibition of both pathways led to p21 restoration, decreased cell proliferation, and induced apoptosis. In addition, the dual inhibition strategy was determined to be synergistic in MDA-MB-231 and BT-549 cells and was relatively nontoxic in the nonneoplastic MCF-10 cell line. In summary, the results from this study provide a unique prospective into the utility of a novel dual inhibition strategy for targeting TNBCs. 相似文献
8.
Determination of lymphoid cell fate is dependent on the expression status of the IL-7 receptor 总被引:4,自引:0,他引:4
Signaling through the IL-7 receptor (IL-7R) is necessary for the development of the earliest B- and T-lineage cells. IL-7R is first expressed on common lymphoid progenitor cells and is not detected on primitive common myeloid progenitors. In this study, we show that enforced expression of IL-7R on multipotential stem cells does not influence lymphoid versus myeloid cell fate. T cell development was compatible with sustained IL-7R expression; however, we observed a near complete block in B cell development at the onset of B-lineage commitment. Unlike pre-proB cells from control animals, developmentally-arrested IL-7R(+)B220(+)CD19(-)NK1.1(-)Ly-6C(-) cells failed to express EBF and Pax5. These results suggest that transient downregulation of IL-7R signaling is a necessary event for induction of EBF and Pax5 expression and B-lymphocyte commitment. 相似文献
9.
Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae 总被引:10,自引:2,他引:8
Arginine decarboxylase (ADC) is an important enzyme in the production of
putrescine and polyamines in plants. It is encoded by a single or low-copy
nuclear gene that lacks introns in sequences studied to date. The rate of
Adc amino acid sequence evolution is similar to that of ndhF for the
angiosperm family studied. Highly conserved regions provide several target
sites for PCR priming and sequencing and aid in nucleotide and amino acid
sequence alignment across a range of taxonomic levels, while a variable
region provides an increased number of potentially informative characters
relative to ndhF for the taxa surveyed. The utility of the Adc gene in
plant molecular systematic studies is demonstrated by analysis of its
partial nucleotide sequences obtained from 13 representatives of
Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order
Capparales) and 1 from the related order Malvales. Two copies of the Adc
gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied
to data except the basal genus Aethionema. The resulting Adc gene tree
provides robust phylogenetic data regarding relationships within the
complex mustard family, as well as independent support for proposed tribal
realignments based on other molecular data sets such as those from
chloroplast DNA.
相似文献
10.
The effects of P2X7 receptor antagonists on the formation and function of human osteoclasts in vitro
Agrawal A Buckley KA Bowers K Furber M Gallagher JA Gartland A 《Purinergic signalling》2010,6(3):307-315
The P2X7 receptor (P2X7R) has been implicated in the process of multinucleation and cell fusion. We have previously demonstrated
that blockade of P2X7Rs on osteoclast precursors using a blocking antibody inhibited multinucleated osteoclast formation in
vitro, but that P2X7R KO mice maintain the ability to form multinucleated osteoclasts. This apparent contradiction of the
role the P2X7R plays in multinucleation has prompted us to examine the effect of the most commonly used and recently available
P2X7R antagonists on osteoclast formation and function. When added to recombinant RANKL and M-CSF human blood monocytes cultures,
all but one compound, decreased the formation and function of multinucleated TRAP-positive osteoclasts in a concentration-dependent
manner. These data provide further evidence for the role of the P2X7R in the formation of functional human multinucleated
osteoclasts and highlight the importance of selection of antagonists for use in long-term experiments. 相似文献