Effect of triclocarban on membrane potential of rat thymocytes : Assessment with bis-(1,3-dibutylbarbituric acid)trimethine oxonol

The effect of triclocarban (TCC), an　environmental pollutant from household items and health care products, on membrane potential of rat thymocytes was examined by a flow cytometry with a fluorescent probe sensitive to membrane potential, bis-(1,3-dibutylbarbituric acid)trimethine oxonol, because TCC changes intracellular ionic circumstance that may affect the membrane potential. TCC at 0.3 μM or more (up to 3 μM) depolarized the membranes. This TCC-induced phenomenon was against our prediction because TCC increases intracellular Ca2+ concentration that activates Ca2+-dependent K+ channels, resulting in a hyperpolarization. The depolarization was still observed under Ca2+-free condition, but not under Na+-free condition. Furthermore, TCC hyperpolarized the membranes under Ca2+- and Na+-free condition. To see if TCC inhibits Ca2+-dependent hyperpolarization, the effect of A23187, a calcium ionophore, on the membrane potential was examined in the cells treated with TCC. A23187 induced large depolarization in the cells treated with 0.3–3 μM TCC. The A23187-induced depolarization in the presence of TCC was greatly attenuated under Na+-free or Ca2+-free condition whereas A23187 elicited hyperpolarization in the cells treated with 0.3–3 μM TCC under Ca2+- and Na+-free condition. Results suggest that 0.3–3 μM TCC increases membrane permeability of Na+ and Ca2+, resulting in the depolarization. Large depolarization induced by TCC in the presence of external Ca2+ and Na+ may mask the hyperpolarization elicited via the increase in intracellular Ca2+ concentration by TCC. Thus, there is a possibility that TCC depolarizes membranes of lymphocytes, resulting in alteration of cellular functions of lymphocytes

CCN3 and bone marrow cells

CCN3 expression was observed in a broad variety of tissues from the early stage of development. However, a kind of loss of function in mice (CCN3 del VWC domain -/-) demonstrated mild abnormality, which indicates that CCN3 may not be critical for the normal embryogenesis as a single gene. The importance of CCN3 in bone marrow environment becomes to be recognized by the studies of hematopoietic stem cells and Chronic Myeloid Leukemia cells. CCN3 expression in bone marrow has been denied by several investigations, but we found CCN3 positive stromal and hematopoietic cells at bone extremities with a new antibody although they are a very few populations. We investigated the expression pattern of CCN3 in the cultured bone marrow derived mesenchymal stem cells and found its preference for osteogenic differentiation. From the analyses of in vitro experiment using an osteogenic mesenchymal stem cell line, Kusa-A1, we found that CCN3 downregulates osteogenesis by two different pathways; suppression of BMP and stimulation of Notch. Secreted CCN3 from Kusa cells inhibited the differentiation of osteoblasts in separate culture, which indicates the paracrine manner of CCN3 activity. CCN3 may also affect the extracellular environment of the niche for hematopoietic stem cells

Substituent-controlled Constructions of M2L4 Cage and 1D Network Structures for Cu(II) Complexes with Bis-benzimidazole Ligands

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Two New Cu(II) Coordination Polymers with 2D and 1D Frameworks that Show Reversible Structural Transformations Depending on the Present Solvents

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Selenolactams as Synthetic Intermediates for the Synthesis of Polycyclic Amines via Seleno-Claisen Rearrangements

A highly diastereoselective α-allylation of selenolactams with allyl halides is reported. DFT analyses and experimental observations suggested that this reaction proceeds via a <i>Se</i>-allylation of the eneselenolates of the lactams followed by a seleno-Claisen rearrangement. The thus-obtained products could be efficiently transformed into polycyclic amines using a previously developed sequential addition of organometallic reagents and ring-closing metathesis

Selenolactams as Synthetic Intermediates for the Synthesis of Polycyclic Amines via Seleno-Claisen Rearrangements

A highly diastereoselective α-allylation of selenolactams with allyl halides is reported. DFT analyses and experimental observations suggested that this reaction proceeds via a <i>Se</i>-allylation of the eneselenolates of the lactams followed by a seleno-Claisen rearrangement. The thus-obtained products could be efficiently transformed into polycyclic amines using a previously developed sequential addition of organometallic reagents and ring-closing metathesis

Selenolactams as Synthetic Intermediates for the Synthesis of Polycyclic Amines via Seleno-Claisen Rearrangements

A highly diastereoselective α-allylation of selenolactams with allyl halides is reported. DFT analyses and experimental observations suggested that this reaction proceeds via a <i>Se</i>-allylation of the eneselenolates of the lactams followed by a seleno-Claisen rearrangement. The thus-obtained products could be efficiently transformed into polycyclic amines using a previously developed sequential addition of organometallic reagents and ring-closing metathesis

Selenolactams as Synthetic Intermediates for the Synthesis of Polycyclic Amines via Seleno-Claisen Rearrangements

A highly diastereoselective α-allylation of selenolactams with allyl halides is reported. DFT analyses and experimental observations suggested that this reaction proceeds via a <i>Se</i>-allylation of the eneselenolates of the lactams followed by a seleno-Claisen rearrangement. The thus-obtained products could be efficiently transformed into polycyclic amines using a previously developed sequential addition of organometallic reagents and ring-closing metathesis