ABSTRACT
Spin transition has attracted the interest of researchers in various fields since the early 1930s, with thousands of examples now recognized, including those in minerals and biomolecules. However, so far the metal centres in which it has been found to occur are almost always octahedral six-coordinate 3d(4) to 3d(7) metals, such as Fe(II). A five-coordinate centre is only rarely seen. Here we report that under pressure SrFe(II)O(2), which features a four-fold square-planar coordination, exhibits a transition from high spin (S = 2) to intermediate spin (S = 1). This is accompanied by a transition from an antiferromagnetic insulating state to a ferromagnetic so-called half-metallic state: only half of the spin-down (d(xz),d(yz)) states are filled. These results highlight the square-planar coordinated iron oxides as a new class of magnetic and electric materials.
Subject(s)
Ferric Compounds/chemistry , Electric Impedance , Electrons , Magnetics , Pressure , Spectroscopy, Mossbauer , Strontium/chemistry , X-Ray DiffractionABSTRACT
Trophinin is a membrane protein that mediates apical cell adhesion between trophoblastic cells and luminal epithelial cells of the endometrium and is implicated in the initial attachment during the process of human embryo implantation. The present study identified novel trophinin gene transcripts, which encode proteins structurally distinct from trophinin protein in the mouse. We designated these proteins "magphinins," because they share consensus amino acid sequences with MAGE (melanoma-associated antigen) superfamily proteins. Among many MAGE proteins, magphinins are closely related to NRAGE, which mediates p75 neurotrophin receptor-dependent apoptosis, and necdin, which is a strong suppressor of cell proliferation in post-mitotic neurons. There are three major forms of magphinins, i.e. magphinin-alpha, -beta, and -gamma, in the mouse, which are formed due to alternative usage of different exons. Northern blot analysis revealed that magphinins are expressed in brain, ovary, testis, and epididymis. In addition, Western blot analysis and in vitro translation experiments showed that magphinins expressed in the mouse ovary and testis are translation products utilizing the second initiation AUG codon and contain an active nuclear localization signal. Ectopic expression of magphinins in mammalian cells resulted in nuclear localization of magphinin and suppressed cell proliferation. Immunohistochemistry of the mouse ovary and testis showed that magphinin proteins are distributed in the cytoplasm of the male and female germ cells, whereas these proteins are translocated to the nucleus at a specific stage of gametogenesis. These results strongly suggest that magphinins regulate cell proliferation during gametogenesis in the mouse.
Subject(s)
Alternative Splicing/genetics , Cell Adhesion Molecules/genetics , Cell Division/physiology , Gametogenesis/physiology , Amino Acid Sequence , Animals , Cell Adhesion Molecules/chemistry , Cell Adhesion Molecules/classification , Cell Adhesion Molecules/metabolism , Cell Line , Female , Humans , Immunohistochemistry , In Situ Hybridization , Male , Mice , Models, Biological , Molecular Sequence Data , Multigene Family , Ovary/cytology , Ovary/metabolism , Phylogeny , Protein Structure, Tertiary , RNA, Messenger/metabolism , Sequence Alignment , Testis/cytology , Testis/metabolism , Tissue DistributionABSTRACT
A 70-year-old man with advanced Borrmann type 4 was preoperatively treated with 5-FU-MMC combined chemotherapy. The primary tumor including a palpable mass in the abdomen was diminished, and eventually the patient underwent curative resection. This preoperative regimen for advanced Borrmann type 4 gastric cancer might be recommended from the standpoint of less adverse effects of chemotherapy. The patient died suddenly of cardiac infarction in 9 months without recurrent signs.
