Construction and Piezoelectric Properties of a Single-Peptide Nanotube Composed of Cyclic β-peptides with Helical Peptides on the Side Chains

To develop nanopiezoelectronics, it is necessary to investigate the relationship between the sizes and piezoelectric properties of the material. Peptide nanotubes (PNTs) composed of cyclic β-peptides have been studied as leading candidates for nanopiezoelectric materials. The current drawback of PNTs is aggregation to form a PNT bundle structure due to strong dipole–dipole interactions between PNTs. Here, we report the construction and piezoelectric properties of single PNTs without nonspecific aggregation by side-chain modification of helical peptides. A cyclic tri-β-peptide with a helical peptide was prepared by multiple-step liquid-phase peptide synthesis and assembled into PNTs by the vapor diffusion method. These nanotubes were characterized by polarized light microscopy and Fourier transform infrared (FTIR) spectroscopy. Additionally, atomic force microscopy (AFM) topographic images showed nanotubes with a height of 4 nm, which corresponds to the diameter of a PNT on a gold-coated mica substrate, indicating that a single PNT was prepared successfully. The converted piezoelectric response of a single PNT was determined to be 1.39 ± 0.12 pm/V. This value was consistent with that of a PNT bundle, which reveals that the piezoelectricity of PNTs is induced by deformation of their cyclic skeletons and is independent of the bundled structure. This finding not only demonstrates a new molecular design strategy to construct these smallest piezoelectric biomaterials by controlling the supramolecular hierarchical structures but also provides insights into the correlation between molecular assembly morphology and size-dependent piezoelectric properties

女児尿道ポリープの1例

Urethral polyps are rarely found in young girls. A total of 12 urethral polyps have been described in young girls in the English literature to date. Here we present a case of urethral polyp that was detected in the distal urethra of a 12-year-girl. Her chief complaint was a sudden blood discharge. On examination, a 15 x 9 mm polypoid mass with a 7 mm pedicle was seen protruding from the urethral meatus. The mass was excised under general anesthesia. Histopathologically, the polyp was covered with urothelium and squamous epithelium, and was composed of congested blood vessels and inflammatory infiltrates. These findings were similar to those of urethral caruncles in postmenopausal female. She has been free from recurrence and has had no complications, as of 12 months after excision.症例は12歳, 女児。生来健康。約1年前より外尿道口から脱出する腫瘤に気付くも症状なく放置していた。2005年10月に外陰部より突然の出血を認めたため, 近医を受診。外尿道口より脱出する小指頭大のポリープを認め, 同年10月31日, 精査加療目的に当院紹介となった。受診時, 他に理学所見上, 特に異常認めず, また尿沈渣, 血液学的検査, エコー, IVPなどにおいても異常所見を認めなかった。同年11月10日全身麻酔下, 尿道膀胱鏡および尿道ポリープ切除術を施行した。尿道鏡にて前部尿道の6時にポリープの起始部を認めた。膀胱内に特に異常所見は認めなかった。起始部からポリープを鋭的に切除し, 欠損部を5-0 PDSにて縫合した。術後経過は良好で術後1日目に尿道カテーテル抜去, 2日目に退院となった。病理組織学的検査にて尿道ポリープは移行上皮および扁平上皮に覆われ, 上皮下組織に小血管の増生と著明な炎症細胞の浸潤を認め, 尿道カルンクラに非常に類似していた。腫瘍性変化や異型細胞の増殖は認めなかった。現在, 術後1年が経過しているが, 再発, 合併症など認めていない。小児における尿道ポリープは稀な疾患であるが, 男児に比べ女児における報告はさらに少ない。われわれが調べうる限り12例の女児尿道ポリープが報告されている。またBen-Meirらは思春期前の女児尿道ポリープの5症例を検討し, 病理組織学的に尿道カルンクラとの類似性を指摘している。今回, われわれは女児尿道ポリープの1例を経験したので若干の文献的考察を加え, ここに報告する。(著者抄録

Analysis of an alternative human CD133 promoter reveals the implication of Ras/ERK pathway in tumor stem-like hallmarks

<p>Abstract</p> <p>Background</p> <p>An increasing number of studies support the presence of stem-like cells in human malignancies. These cells are primarily responsible for tumor initiation and thus considered as a potential target to eradicate tumors. CD133 has been identified as an important cell surface marker to enrich the stem-like population in various human tumors. To reveal the molecular machinery underlying the stem-like features in tumor cells, we analyzed a promoter of <it>CD133 </it>gene using human colon carcinoma Caco-2 and synovial sarcoma Fuji cells, which endogenously express <it>CD133 </it>gene.</p> <p>Results</p> <p>A reporter analysis revealed that P5 promoter, located far upstream in a human <it>CD133 </it>gene locus, exhibits the highest activity among the five putative promoters (P1 to P5). Deletion and mutation analysis identified two ETS binding sites in the P5 region as being essential for its promoter activity. Electrophoretic mobility shift assays demonstrated the specific binding between nuclear factors and the ETS binding sequence. Overexpression of dominant-negative forms of Ets2 and Elk1 resulted in the significant decrease of P5 activity. Furthermore, treatment of Fuji cells with a specific MEK/ERK inhibitor, U0126, also markedly decreased CD133 expression, but there was no significant effect in Caco-2 cells, suggesting cell type-specific regulation of CD133 expression. Instead, the side population, another hallmark of TSLCs, was dramatically diminished in Caco-2 cells by U0126. Finally, Ras-mediated oncogenic transformation in normal human astrocytes conferred the stem-like capability to form neurosphere-like colonies with the increase of <it>CD133 </it>mRNA expression.</p> <p>Conclusions</p> <p>In conclusion, the Ras/ERK pathway at least in part contributes to the maintenance and the acquisition of stem-like hallmarks, although the extent of its contribution is varied in a cell type-specific manner. These findings could help our comprehensive understanding of tumor stemness, and also improve the development of eradicative therapies against human malignancies.</p