These fittings revealed notable ferromagnetic short-range correlations and pure ion-ion spin relaxation in the paramagnetic state of La0.3Ca0.7MnO3. The latter fact supports the local nature of ferromagnetic double exchange coupling in this very
case. It is suggested that such character of ferromagnetic exchange interactions results in the localization of carriers and establishing of charge ordered antiferromagnetic insulating ground state. This finding may be considered a strong prerequisite for the electron-hole doping asymmetry observed in the phase diagram of La-Ca manganites. (C) 2011 American Institute of Physics. [doi:10.1063/1.3540309]“
“Background: Skin-derived antimicrobial peptides, such as human beta-defensins and cathelicidins, actively contribute to host defense by inactivating microorganisms. Catestatin, a neuroendocrine peptide that affects human autonomic MLN2238 functions, has recently been detected in keratinocytes upon injury/infection where it inhibits the growth of pathogens. Human catestatin exhibits three single nucleotide polymorphisms: Gly364Ser, Pro370Leu, and Arg374Gln.
Objective: To investigate the effects of human catestatin and its variants on keratinocyte migration and proliferation, and to elucidate the possible signaling mechanisms involved.
Methods: The migration of normal human keratinocytes was analyzed using
Boyden microchamber assay
and in vitro wound closure assay. Cell proliferation was evaluated by BrdU incorporation, cell count assay and cell cycle analysis. Intracellular Ca(2+) Selleck PX-478 mobilization was measured using a fluorescent calcium assay kit. The phosphorylation of epidermal growth factor receptor (EGFR), Akt, and MAPKs was determined by Western blotting.
Results: Catestatin and its variants dose-dependently enhanced keratinocyte migration and proliferation. Moreover, catestatin peptides increased intracellular Ca(2+) mobilization and induced the phosphorylation of EGFR, Akt, extracellular signal-regulated kinase (ERK), and p38 in keratinocytes. The induction of keratinocyte migration and proliferation by catestatin XMU-MP-1 concentration peptides involved G-proteins, phospholipase C, EGFR, PI3-kinase, ERK, and p38, as evidenced by the specific inhibitory effects of pertussis toxin (G-protein inhibitor), U-73122 (phospholipase C inhibitor), AG1478 (EGFR inhibitor), anti-EGFR antibody, wortmannin (PI3-kinase inhibitor), U0126 (ERK inhibitor), and SB203580 (p38 inhibitor), respectively.
Conclusion: Besides inhibiting the growth of skin pathogens, catestatin peptides may also contribute to cutaneous wound closure by enhancing keratinocyte migration and proliferation at the wound site. (C) 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.