Iridium complex, a phosphorescent light-emitting diode material, serves as a novel chemical probe for imaging hypoxic tumor tissues

Iridium complex, a promising organic light-emitting diode for next generation television displays, emits phosphorescence. Phosphorescence is quenched by oxygen. We used this oxygen-quenching feature for imaging tumor hypoxia. Red light-emitting iridium complex Ir(btp)~2~(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was in parallel with HIF-1[alpha] expression. BTP was further applied to imaging five tumors (four from human origin and one from mouse origin) transplanted in athymic mice. All tumors presented a bright BTP-emitting image even 5 min after the injection. The BTP-dependent tumor image peaked at 1 to 2 h after the injection, and was then cleared from tumors within 24 h. The minimal BTP image recognition size was 3 to 4 mm in diameter. Compared with ^18^F-FDG/PET images, BTP delineated a clearer image for a tumor profile. We suggest that iridium complex has a vast potential for imaging hypoxic lesions such as tumor tissues

Super-chiral vibrational spectroscopy with metasurfaces for high-sensitive identification of alanine enantiomers

Chiral nature of an enantiomer can be characterized by circular dichroism (CD) spectroscopy, but such a technique usually suffers from weak signal even with a sophisticated optical instrument. Recent demonstrations of plasmonic metasurfaces showed that chiroptical interaction of molecules can be engineered, thereby greatly simplifying a measurement system with high sensing capability. Here, by exploiting super-chiral field in a metasurface, we experimentally demonstrate high-sensitive vibrational CD spectroscopy of alanine enantiomers, the smallest chiral amino acid. Under linearly polarized excitation, the metasurface consisting of an array of staggered Au nano-rods selectively produces the left- and right-handed super-chiral fields at 1600 cm−1, which spectrally overlaps with the functional group vibrations of alanine. In the Fourier-transform infrared spectrometer measurements, the mirror symmetric CD spectra of D- and L-alanine are clearly observed depending on the handedness of the metasurface, realizing the reliable identification of small chiral molecules. The corresponding numerical simulations reveal the underlying resonant chiroptical interaction of plasmonic modes of the metasurface and vibrational modes of alanine. Our approach demonstrates a high-sensitive vibrational CD spectroscopic technique, opening up a reliable chiral sensing platform for advanced infrared inspection technologies

Monocyte/macrophage response to β2-microglobulin modified with advanced glycation end products

Monocyte/macrophage response to β2-microglobulin modified with advanced glycation end products. We recently found that acidic β2-microglobulin (β2m), a major isoform of β2m in amyloid fibrils of patients with dialysis-related amyloidosis (DRA), contained early Amadori products and advanced glycation end products (AGEs) formed nonenzymatically between sugar and protein. Further analysis revealed that acidic β2m induces monocyte chemotaxis and macrophage secretion of bone-resorbing cytokines, suggesting the involvement of acidic β2m in the pathogenesis of DRA. Acidic β2m, however, is a mixture of heterogeneous molecular adducts due to various types of modification. In the present study, we investigated the modification responsible for the biological activity of acidic β2m toward monocytes/macrophages. The presence of a fair amount of β2m species with deamidation was detected in acidic β2m isolated from urine of non-diabetic long-term hemodialysis patients, but deamidated β2m had no biological activity. In contrast, normal β2m acquired the activity upon incubation with glucose in vitro. Among the glycated β2m, the pigmented and fluorescent β2m that formed after a long incubation period, that is, AGE-modified β2m, exhibited biological activity, whereas β2m modified with Amadori products, major Maillard products in acidic β2m, had no such activity. These findings suggest that AGEs, although only a minor constituent of acidic β2m, are responsible for monocyte chemotaxis and macrophage secretion of cytokines, implicating the contribution of AGEs to bone and joint destruction in DRA

Chemerin enhances insulin signaling and potentiates insulin-stimulated glucose uptake in 3T3-L1 adipocytes

AbstractTo explore a novel adipokine, we screened adipocyte differentiation-related gene and found that TIG2/chemerin was strongly induced during the adipocyte differentiation. Chemerin was secreted by the mature 3T3-L1 adipocytes and expressed abundantly in adipose tissue in vivo as recently described. Intriguingly, the expression of chemerin was differently regulated in the liver and adipose tissue in db/db mice. In addition, serum chemerin concentration was decreased in db/db mice. Chemerin and its receptor/ChemR23 were expressed in mature adipocytes, suggesting its function in autocrine/paracrine fashion. Finally, chemerin potentiated insulin-stimulated glucose uptake concomitant with enhanced insulin signaling in the 3T3-L1 adipocytes. These data establish that chemerin is a novel adipokine that regulates adipocyte function

Achievement of JARE routine observation of marine biology and its future perspectives

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月17日（木） 統計数理研究所 3階セミナー室