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In vivo neutralization of TNF-alpha promotes humoral autoimmunity by preventing the induction of CTL. 总被引:3,自引:0,他引:3
C S Via A Shustov V Rus T Lang P Nguyen F D Finkelman 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(12):6821-6826
Neutralization of TNF-alpha in humans with rheumatoid arthritis or Crohn's disease has been associated with the development of humoral autoimmunity. To determine the effect of TNF-alpha neutralization on cell-mediated and humoral-mediated responses, we administered anti-TNF-alpha mAb to mice undergoing acute graft-vs-host disease (GVHD) using the parent-into-F(1) model. In vivo neutralization of TNF-alpha blocked the lymphocytopenic features characteristic of acute GVHD and induced a lupus-like chronic GVHD phenotype (lymphoproliferation and autoantibody production). These effects resulted from complete inhibition of detectable antihost CTL activity and required the presence of anti-TNF-alpha mAb for the first 4 days after parental cell transfer, indicating that TNF-alpha plays a critical role in the induction of CTL. Moreover, an in vivo blockade of TNF-alpha preferentially inhibited the production of IFN-gamma and blocked IFN-gamma-dependent up-regulation of Fas; however, cytokines such as IL-10, IL-6, or IL-4 were not inhibited. These results suggest that a therapeutic TNF-alpha blockade may promote humoral autoimmunity by selectively inhibiting the induction of a CTL response that would normally suppress autoreactive B cells. 相似文献
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Oat leaf base: tissue with an efficient regeneration capacity 总被引:1,自引:1,他引:0
Summary An efficient short term regeneration system using seedling derived oat (Avena sativa) leaf tissue has been developed. Callus derived from the leaf base showed a higher response of plant regeneration than callus initiated from mesocotyls and more mature parts of the leaves. A correlation between the nuclear DNA content of the donor material, as analysed with flow cytometry, and its ability to form callus was observed. Somatic embryogenesis was histologically recognised from callus derived from tissue close to the apical meristem. Plant regeneration media with various concentrations of auxin were tested. Callus from three different cultivars had a similar regeneration potential with an optimal regeneration frequency of 60%. About 2 months after inoculation regenerated plantlets could be moved to a greenhouse for cultivation.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- DAPI
6-diamidino-2-phenylindole
- IAA
indole-3-acetic acid
- KT
kinetin
- MS
Murashige and Skoog's medium
- NAA
naphthalene acetic acid 相似文献
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Electron spin resonance of eumelanin from hair: photoinduced radicals in solid matrix 总被引:1,自引:0,他引:1
R Bibang R Arnaud J Lemaire A Deflandre G Lang 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》1989,2(5):387-394
KBr matrices appear to be convenient media to reveal the radicals formed on light exposure of eumelanin dispersions. The ESR signal of eumelanin dispersed at low concentration in KBr pellets is analyzed during and after irradiation at various wavelengths. Different types of radicals are observed. R'1- and R1-types of radicals are assigned, respectively, to neutral and deprotonated intrinsic phenoxy radicals of eumelanin. R'1 can be oxidized by oxygen as opposite to R1. R2- and R'2-types are formed in the indolic site. Water favours the conversion of R2, unreactive with oxygen, into R'2 which can be oxidized. R'1 and R2 result of an electron photoejection, respectively, from the phenolic and the indolic site. The R3-type radicals are associated with the band-to-band excitation of eumelanin considered as a semiorganized solid. 相似文献
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Although anesthetics are known to cause respiratory and cardiovascular depression in humans, these adverse effects rarely have been investigated in laboratory rodents. This study evaluated the effects of four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam on the respiratory and cardiovascular systems of rats. Results showed marked acidosis, hypercarbia and hypoxia with high doses of Innovar-Vet, moderate respiratory depression with all dosages of pentobarbital and minimal respiratory depression with ketamine-xylazine and ketamine-diazepam. Innovar-Vet, ketamine-xylazine and pentobarbital caused profound hypotension, particularly at high dosages, while ketamine-diazepam caused the least depression in mean arterial blood pressure of all drugs evaluated. None of the drugs studied produced significant alterations in heart rate. Throughout all dosages investigated, the ketamine-diazepam combination showed the least overall effects on ventilation and perfusion of the four parenteral drug combinations studied. 相似文献