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排序方式: 共有397条查询结果,搜索用时 46 毫秒
171.
Zusammenfassung Wenn die Lösung zu 50% aus schwerem Wasser bestand, blieb die Bildung von Antigen-Antikörperpräcipitat im Bereich des Antikörperüberschusses unverändert. Dies zeigt, dass die Substitution mit Deuterium die spezifischen Bindungseigenschaften nicht verändert. Dagegen fand sich eine erhöhte Niederschlagsmenge im Bereich des Antigenüberschusses, was auf eine Herabsetzung der Löslichkeit des normalerweise löslichen Antigen-Antikörperkomplexes hinweist. 相似文献
172.
Mechanical failure modes leading to cracks or breeches in proton exchange membrane fuel cells are driven by mechanical forces associated with swelling from water uptake and shrinkage from dehumidifi-cation. To determine the magnitude of compressive mechanical stress imposed by water swelling in a proton exchange fuel-cell membrane, the osmotic pressure of water in a perfluorosulfonic acid ionomer (Nafion? N 117) membrane was measured using a hydrostatic piston-cylinder device with an in-situ hydrophilic frit. Experiments indicate that hydrostatic stresses greater than 103.5 MPa are created in a membrane when swollen with water at 23℃ suggesting that pressure from water swelling can distort Nafion N 117-based structures as the osmotic pressure is of the same order of magnitude as the flow stress of Nafion N 117. 相似文献
173.
M. H. Ravindranath S. M. Brazeau D. L. Morton 《Cellular and molecular life sciences : CMLS》1994,50(7):648-653
Murine B16 melanoma expresses the ganglioside. GM3. GM3 shed from tumor cells is immunosuppressive and promotes tumor growth1. Reduction or elimination of the shed GM3 could be therapeutic, and the anti-GM3 antibodies may reduce and clear the shed ganglioside. To test this hypothesis, mice were challenged with tumor cells, with or without inducing anti-GM3 antibody response. Since gangliosides are poor immunogens and T-cell independent antigens, an adjuvant (monophosphoryl lipid A (MPL), a non-toxic lipid A ofSalmonella), directed against B-cells, was employed. MPL was incorporated onto liposomes and into the surface membrane of B16 mouse melanoma cells; both are rich in GM3. C57BL/6J mice immunized with MPL-liposomes or MPL-B16 cells responded with elevated levels of anti-GM3 IgM. Non-immunized mice or mice immunized with B16 cells alone or ganglioside GM3 alone (without MPL) elicited poor anti-GM3 IgM response, confirming the GM3's immunologic crypticity and MPL's immunopotentiating effect. MPL's immunopotentiating effect was improved by coupling it to melanoma cell membranes C57BL/6J mice were immunized with irradiated B16 alone or MPL alone or MPL-conjugated irradiated B16. After three weekly immunizations, each mouse received a challenge dose of viable syngeneic B16. Neither MPL alone nor B16 alone had a significant effect on tumor growth or host survival; however, administration of MPL-conjugated B16 cells significantly prevented tumor growth and prolonged survival. Our results indicate that MPL-incorporated B16 cells augment the anti-GM3 IgM response, which may reverse GM3-induced immunosuppression by eliminating tumor-derived GM3, and restore immunocompetence. 相似文献
174.
Stefater JA Lewkowich I Rao S Mariggi G Carpenter AC Burr AR Fan J Ajima R Molkentin JD Williams BO Wills-Karp M Pollard JW Yamaguchi T Ferrara N Gerhardt H Lang RA 《Nature》2011,474(7352):511-515
Myeloid cells are a feature of most tissues. Here we show that during development, retinal myeloid cells (RMCs) produce Wnt ligands to regulate blood vessel branching. In the mouse retina, where angiogenesis occurs postnatally, somatic deletion in RMCs of the Wnt ligand transporter Wntless results in increased angiogenesis in the deeper layers. We also show that mutation of Wnt5a and Wnt11 results in increased angiogenesis and that these ligands elicit RMC responses via a non-canonical Wnt pathway. Using cultured myeloid-like cells and RMC somatic deletion of Flt1, we show that an effector of Wnt-dependent suppression of angiogenesis by RMCs is Flt1, a naturally occurring inhibitor of vascular endothelial growth factor (VEGF). These findings indicate that resident myeloid cells can use a non-canonical, Wnt-Flt1 pathway to suppress angiogenic branching. 相似文献
175.
Exome sequencing identifies frequent mutation of the SWI/SNF complex gene PBRM1 in renal carcinoma 总被引:1,自引:0,他引:1
Varela I Tarpey P Raine K Huang D Ong CK Stephens P Davies H Jones D Lin ML Teague J Bignell G Butler A Cho J Dalgliesh GL Galappaththige D Greenman C Hardy C Jia M Latimer C Lau KW Marshall J McLaren S Menzies A Mudie L Stebbings L Largaespada DA Wessels LF Richard S Kahnoski RJ Anema J Tuveson DA Perez-Mancera PA Mustonen V Fischer A Adams DJ Rust A Chan-on W Subimerb C Dykema K Furge K Campbell PJ Teh BT Stratton MR Futreal PA 《Nature》2011,469(7331):539-542
176.
177.
178.
McDermott-Roe C Ye J Ahmed R Sun XM Serafín A Ware J Bottolo L Muckett P Cañas X Zhang J Rowe GC Buchan R Lu H Braithwaite A Mancini M Hauton D Martí R García-Arumí E Hubner N Jacob H Serikawa T Zidek V Papousek F Kolar F Cardona M Ruiz-Meana M García-Dorado D Comella JX Felkin LE Barton PJ Arany Z Pravenec M Petretto E Sanchis D Cook SA 《Nature》2011,478(7367):114-118
Left ventricular mass (LVM) is a highly heritable trait and an independent risk factor for all-cause mortality. So far, genome-wide association studies have not identified the genetic factors that underlie LVM variation, and the regulatory mechanisms for blood-pressure-independent cardiac hypertrophy remain poorly understood. Unbiased systems genetics approaches in the rat now provide a powerful complementary tool to genome-wide association studies, and we applied integrative genomics to dissect a highly replicated, blood-pressure-independent LVM locus on rat chromosome 3p. Here we identified endonuclease G (Endog), which previously was implicated in apoptosis but not hypertrophy, as the gene at the locus, and we found a loss-of-function mutation in Endog that is associated with increased LVM and impaired cardiac function. Inhibition of Endog in cultured cardiomyocytes resulted in an increase in cell size and hypertrophic biomarkers in the absence of pro-hypertrophic stimulation. Genome-wide network analysis unexpectedly implicated ENDOG in fundamental mitochondrial processes that are unrelated to apoptosis. We showed direct regulation of ENDOG by ERR-α and PGC1α (which are master regulators of mitochondrial and cardiac function), interaction of ENDOG with the mitochondrial genome and ENDOG-mediated regulation of mitochondrial mass. At baseline, the Endog-deleted mouse heart had depleted mitochondria, mitochondrial dysfunction and elevated levels of reactive oxygen species, which were associated with enlarged and steatotic cardiomyocytes. Our study has further established the link between mitochondrial dysfunction, reactive oxygen species and heart disease and has uncovered a role for Endog in maladaptive cardiac hypertrophy. 相似文献
179.
Li W Bloom JS Podsiadlowski P Miller AA Cenko SB Jha SW Sullivan M Howell DA Nugent PE Butler NR Ofek EO Kasliwal MM Richards JW Stockton A Shih HY Bildsten L Shara MM Bibby J Filippenko AV Ganeshalingam M Silverman JM Kulkarni SR Law NM Poznanski D Quimby RM McCully C Patel B Maguire K Shen KJ 《Nature》2011,480(7377):348-350
Type Ia supernovae are thought to result from a thermonuclear explosion of an accreting white dwarf in a binary system, but little is known of the precise nature of the companion star and the physical properties of the progenitor system. There are two classes of models: double-degenerate (involving two white dwarfs in a close binary system) and single-degenerate models. In the latter, the primary white dwarf accretes material from a secondary companion until conditions are such that carbon ignites, at a mass of 1.38 times the mass of the Sun. The type Ia supernova SN 2011fe was recently detected in a nearby galaxy. Here we report an analysis of archival images of the location of SN 2011fe. The luminosity of the progenitor system (especially the companion star) is 10-100 times fainter than previous limits on other type Ia supernova progenitor systems, allowing us to rule out luminous red giants and almost all helium stars as the mass-donating companion to the exploding white dwarf. 相似文献
180.