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排序方式: 共有117条查询结果,搜索用时 0 毫秒
31.
32.
Intermediate filaments in nervous tissues 总被引:59,自引:30,他引:29
Intermediate filaments have been isolated from rabbit intradural spinal nerve roots by the axonal flotation method. This method was modified to avoid exposure of axons to low ionic strength medium. The purified filaments are morphologically 75-80 percent pure. The gel electrophoretogram shows four major bands migrating at 200,000, 145,000, 68,000, and 60,000 daltons, respectively. A similar preparation from rabbit brain shows four major polypeptides with mol wt of 200,000 145,000, 68,000, and 51,000 daltons. These results indicate that the neurofilament is composed of a triplet of polypepetides with mol wt of 200,000, 145,000, and 68,000 daltons. The 51,000-dalton band that appears in brain filament preparations as the major polypeptide seems to be of glial origin. The significance of the 60,000- dalton band in the nerve root filament preparation is unclear at this time. Antibodies raised against two of the triplet proteins isolated from calf brain localize by immunofluorescence to neurons in central and peripheral nerve. On the other hand, an antibody to the 51,000-dalton polypeptide gives only glial staining in the brain, and very weak peripheral nerve staining. Prolonged exposure of axons to low ionic strength medium solubilizes almost all of the triplet polypeptides, leaving behind only the 51,000- dalton component. This would indicate that the neurofilament is soluble at low ionic strength, whereas the glial filament is not. These results indicate that neurofilaments and glial filaments are composed of different polypeptides and have different solubility characteristics. 相似文献
33.
A mathematical model of cancer treatment by immunotherapy 总被引:1,自引:0,他引:1
In this paper, a detailed mathematical study of cancer immunotherapy will be presented. General principles of cancer immunotherapy and the model equations and hypotheses will be discussed. Mathematical analyses of the model equations with regard to dissipativity, boundedness of solutions, invariance of non-negativity, nature of equilibria, persistence, extinction and global stability will be analyzed. It will also be shown that bifurcations can occur, and criteria for total cure will also be derived. 相似文献
34.
Machado CM Schenka A Vassallo J Tamashiro WM Gonçalves EM Genari SC Verinaud L 《Cancer cell international》2005,5(1):13
A human malignant continuous cell line, named NG97, was recently established in our laboratory. This cell line has been serially
subcultured over 100 times in standard culture media presenting no sign of cell senescence. The NG97 cell line has a doubling
time of about 24 h. Immunocytochemical analysis of glial markers demonstrated that cells are positive for glial fibrillary
acidic protein (GFAP) and S-100 protein, and negative for vimentin. Under phase-contrast microscope, cultures of NG97 showed
cells with variable morphological features, such as small rounded cells, fusiform cells (fibroblastic-like cells), and dendritic-like
cells. However, at confluence just small rounded and fusiform cells can be observed. At scanning electron microscopy (SEM)
small rounded cells showed heterogeneous microextentions, including blebs and filopodia. Dendritic-like cells were flat and
presented extensive prolongations, making several contacts with small rounded cells, while fusiform cells presented their
surfaces dominated by microvilli. 相似文献
35.
ML Jones 《Biotechnic & histochemistry》2013,88(3):155-159
The discovery of formaldehyde for preserving tissue structures produced a new dimension in microscopy. Preserving structure and morphology became important; therefore, identifying a proper fixing agent for particular structures, chemical entities, and tissues, also became important. The methods for demonstrating tissue structures evolved and were implemented with careful observation and documentation of the results and outcomes. Formalin was incorporated into many techniques, and provided helpful results in many cases and hindrances in others. The effects of formalin on the outcomes of routine and special staining techniques are reported here. 相似文献
36.
Sarcoplasmic Reticulum K+ (TRIC) Channel Does Not Carry Essential Countercurrent during Ca2+ Release
Tao Guo Alma Nani Stephen Shonts Matthew Perryman Haiyan Chen Thomas Shannon Dirk Gillespie Michael Fill 《Biophysical journal》2013,105(5):1151-1160
The charge translocation associated with sarcoplasmic reticulum (SR) Ca2+ efflux is compensated for by a simultaneous SR K+ influx. This influx is essential because, with no countercurrent, the SR membrane potential (Vm) would quickly (<1 ms) reach the Ca2+ equilibrium potential and SR Ca2+ release would cease. The SR K+ trimeric intracellular cation (TRIC) channel has been proposed to carry the essential countercurrent. However, the ryanodine receptor (RyR) itself also carries a substantial K+ countercurrent during release. To better define the physiological role of the SR K+ channel, we compared SR Ca2+ transport in saponin-permeabilized cardiomyocytes before and after limiting SR K+ channel function. Specifically, we reduced SR K+ channel conduction 35 and 88% by replacing cytosolic K+ for Na+ or Cs+ (respectively), changes that have little effect on RyR function. Calcium sparks, SR Ca2+ reloading, and caffeine-evoked Ca2+ release amplitude (and rate) were unaffected by these ionic changes. Our results show that countercurrent carried by SR K+ (TRIC) channels is not required to support SR Ca2+ release (or uptake). Because K+ enters the SR through RyRs during release, the SR K+ (TRIC) channel most likely is needed to restore trans-SR K+ balance after RyRs close, assuring SR Vm stays near 0 mV. 相似文献
37.
Nitric oxide (NO) has been reported to act both as a destructive and a protective agent in the pathogenesis of the injuries
that occur during hypoxia/reoxygenation (H/R). It has been suggested that this dual role of NO depends directly on the isoform
of NO synthase (NOS) involved. In this work, we investigate the role that NO derived from endothelial NOS (eNOS) plays in
cardiac H/R-induced injury. Wistar rats were submitted to H/R (hypoxia for 30 min; reoxygenation of 0 h, 12 h and 5 days),
with or without prior treatment using the selective eNOS inhibitor l-NIO (20 mg/kg). Lipid peroxidation, apoptosis and protein nitration, as well as NO production (NOx), were analysed. The results
showed that l-NIO administration lowered NOx levels in all the experimental groups. However, no change was found in the lipid peroxidation
level, the percentage of apoptotic cells or nitrated protein expression, implying that eNOS-derived NO may not be involved
in the injuries occurring during H/R in the heart. We conclude that l-NIO would not be useful in alleviating the adverse effects of cardiac H/R. 相似文献
38.
Kamilla Mahkamova Nani Md. Latar Sebastian Aspinall Annette Meeson 《Experimental cell research》2019,374(1):104-113
Comparison of studies of cells derived from normal and pathological tissues of the same organ can be fraught with difficulties, particular with cancer where a number of different diseases are considered cancer within the same tissue. In the thyroid, there are 4 main types of cancer, three of which arise from follicular epithelial cells; papillary and follicular which are classified as differentiated, and anaplastic which is classified as undifferentiated.One assay that can be utilised for isolation of cancer stem cells is the side population (SP) assay. However, SP studies have been limited in part due to lack of optimal isolation strategies and in the case of anaplastic thyroid cancer (ATC) are further compounded by lack of access to ATC tumors. We have used thyroid cell lines to determine the optimal conditions to isolate viable SP cells. We then compared SP cells and NSP cells (bulk tumour cells without the SP) of a normal thyroid cell line N-thy ori-3-1 and an anaplastic thyroid cancer cell line SW1736 and showed that both SP cell populations displayed higher levels of stem cell characteristics than the NSP. When we compared SP cells of the N-thy ori-3-1 and the SW1736, the SW1736 SP had a higher colony forming potential, expressed higher levels of stem cell markers and CXCR4 and where more migratory and invasive, invasiveness increasing in response to CXCL12.This is the first report showing functional differences between ATC SP and normal thyroid SP and could lead to the identification of new therapeutic targets to treat ATC. 相似文献
39.
Microbially synthesized modular virus‐like particles and capsomeres displaying group A streptococcus hypervariable antigenic determinants 下载免费PDF全文
40.
Florian Alten Jeremias Motte Carina Ewering Nani Osada Christoph R. Clemens Ella M. Kadas Nicole Eter Friedemann Paul Martin Marziniak 《PloS one》2014,9(11)