B cell hyperresponsiveness and expansion of mature follicular B cells but not of marginal zone B cells in NFATc2/c3 double-deficient mice

Marginal zone (MZ) B cells and peritoneal B-I cells provide a first defense system of thymus-independent Ab responses against foreign pathogens and therefore share a number of functional properties. Recently, development of B-1a cells was shown to be controlled by the transcription factor NFATc1. We show here that mice deficient for NFATc2 and c3 display a distinct lower representation of MZ B cells, which is correlated with a reduced capturing of trinitrophenyl-Ficoll. In contrast, mature follicular B cells from NFATc2/c3(-/-) mice are strongly increased in number. NFATc2/c3-/- B cells exhibit a marked increase in BCR-induced intracellular Ca(2+) mobilization and proliferation. However, trinitrophenyl-Ficoll-specific IgM and IgG3 responses of NFATc2/c3-deficient mice are intact, and chimeric mice reconstituted with NFATc2/3-deficient B cells show a normal number of MZ B cells and normal BCR responses. These observations suggest that the strongly elevated Th2 cytokine milieu in NFATc2/c3-deficient mice leads to a hyperactivation of mature, follicular B cells, whereas MZ B cells are less responsive to these signals

Pim-1 kinase enhances NFATc activity and neuroendocrine functions in PC12 cells

The activity of NFAR family transcription factors is tightly regulated in T cells via signaling pathways initiated by stimulation of the T cell receptor or its downstream effectors such as the Pim-1 serine/threonine kinase. Here, we demonstrate that NFATc-dependent transcription is inducible also in NGF-differentiated rat PC12 pheochromocytoma cells treated with phorbol esthers, calcium ionophores and/or forskolin and that the Pim-1 kinase can further potentiate the effects of these agents. PC 12 cells, share many characteristics with sympathetic neurons and can be induced to produce and release catecholamines, such as dopamine and noradrenaline, and inflammatory cytokines, such as interleukin 6. Interestingly, Pim-1 can synergize with forskolin-induced signaling pathways to stimulate also neuroendocrine functions of PC12 cells. (c) 2005 Elsevier B.V. All rights reserved

Swift Heavy Ion Induced Modification Studies of C60 Thin Films

Modification induced by 110 MeV Ni ion irradiated thin film samples of C60 on Si and quartz substrates were studied at various fluences. The pristine and irradiated samples were investigated using Raman spectroscopy, electrical conductivity and optical absorption spectroscopy. The Raman data and band gap measurements indicate that swift ions at low fluences result in formations that involve multiple molecular units like dimer or polymer. High fluence irradiation resulted in sub-molecular formations and amorphous semiconducting carbon, indicating overall damage of the fullerene molecules. These sub-molecular units have been identified with nanocrystalline diamond and nanocrystalline graphite like formations.Comment: 7 pages, 29 references and 9 figures submitted to J. Appl. Phy

Application of a synchrotron microprobe to the analytical characterization of ion-implanted material

A synchrotron microprobe has been used to characterize ion implantations of nickel and cobalt in silicon (100) or (111) wafers. The synchrotron radiation is collimated by means of a rigid cylindrical glass capillary of 110 mm length, 5 mm outer and 30 μm or 10 μm inner diameter. The beam is pointed at the wafer sample and the emitted radiation of X-rays is detected by an energy dispersive spectrometer. Line scans are recorded step by step over the implantation areas and across their borders. The sharpness of the borders is characterized at a lateral resolution of 13 μm and the edge lengths ranging from 0.6 to 8 mm are determined with an accuracy better than ± 20 μm. The signal intensity and implantation dose of cobalt ranging from 1 × 1015 to 1 × 1017 ions cm−2 show a linear relationship as is to be expected for the micrometre thin implanted layers