Structural phase transition and magnetic-field effect on the modulated structure in GdBaCo2O5+δ (δ < 0.5)

We investigated the crystal structures of an ordered perovskite-type cobaltate, GdBaCo2O(5+δ) (δ < 0.5), at elevated temperatures by transmission electron microscopy. Above the magnetic ordering temperature, we observed a first-order structural phase transition between the low-temperature tetragonal 3a(p) × 3a(p) and high-temperature orthorhombic 1a(p) × 2a(p) superstructure phases (where a(p) is the perovskite-unit cell). Upon the application of a magnetic field, an incommensurate phase emerges around the structural phase-transition temperature, which indicates a magnetic-field-induced structural phase transition via no magnetic ordering in the ordered perovskite-type cobaltate.

Elevated lipogenesis in epithelial stem-like cell confers survival advantage in ductal carcinoma in situ of breast cancer

Upregulation of lipogenesis is a hallmark of cancer and blocking the lipogenic pathway is known to cause tumor cell death by apoptosis. However, the exact role of lipogenesis in tumor initiation is as yet poorly understood. We examined the expression profile of key lipogenic genes in clinical samples of ductal carcinoma in situ (DCIS) of breast cancer and found that these genes were significantly upregulated in DCIS. We also isolated cancer stem-like cells (CSCs) from DCIS.com cell line using cell surface markers (CS24(-)CD44(+)ESA(+)) and found that this cell population has significantly higher tumor-initiating ability to generate DCIS compared with the non-stem-like population. Furthermore, the CSCs showed significantly higher level of expression of all lipogenic genes than the counterpart population from non-tumorigenic breast cancer cell line, MCF10A. Importantly, ectopic expression of SREBP1, the master regulator of lipogenic genes, in MCF10A significantly enhanced lipogenesis in stem-like cells and promoted cell growth as well as mammosphere formation. Moreover, SREBP1 expression significantly increased the ability of cell survival of CSCs from MCF10AT, another cell line that is capable of generating DCIS, in mouse and in cell culture. These results indicate that upregulation of lipogenesis is a pre-requisite for DCIS formation by endowing the ability of cell survival. We have also shown that resveratrol was capable of blocking the lipogenic gene expression in CSCs and significantly suppressed their ability to generate DCIS in animals, which provides us with a strong rationale to use this agent for chemoprevention against DCIS.

Synergistic effect of PKC activation and actin filament disruption on carbonate apatite-facilitated lymphocyte transfection

Leukemia and lymphoma cells are potential targets for genetic manipulation in cancer therapy. On the other hand, genetically modified autologous lymphocytes expressing a chimeric antigen against a receptor overexpressed in tumor cells or tumor vasculature are promising cell-based therapeutics for cancer.However, the lack of a smart device for efficient transgene delivery to the lymphocytes poses the major obstacle to the successful clinical applications of these attractive approaches. Recently, we developed a carbonate apatite-based nanocarrier system for effective intracellular delivery and release of DNA molecules, achieving very high level of transgene expression in both primary and cancer cells. Although its efficacy in human T leukemia cells is relatively poor, immobilization of fibronectin and/or chimeric E-cadherin-Fc on particle surface could enhance transgene delivery in presence of an actin filament disrupter. Here, we report for the first time that simultaneous stimulation of human T leukemia cells by a protein kinase C (PKC) activator, a Ca(2+) ionophore and an actin filament disrupter dramatically accelerated carbonate apatite-mediated transgene delivery in the cells, resulting in over 100-fold more efficacy than commcercially available lipofectamine.

MRI of the anatomical structures of the knee: the proton density-weighted fast spin-echo sequence vs the proton density-weighted fast-recovery fast spin-echo sequence

OBJECTIVE

The purpose of this study was to compare the proton-density (PD)-weighted fast spin-echo (FSE) and fast-recovery FSE (FRFSE) sequences for the evaluation of the anatomical structures of the knee.

METHOD

24 healthy volunteers who underwent MRI by both sagittal PD-weighted FSE and FRFSE sequences were evaluated. The signal-to-noise ratio, contrast-to-noise ratio (CNR) and anatomical detail visualisation were compared for the two techniques.

RESULTS

The mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FRFSE images than for the PD-weighted FSE images in the cartilages/the femorotibial joint effusion and the cruciate ligaments/the effusion around the cruciate ligaments; however, the mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FSE sequences than for the PD-weighted FRFSE sequences in the cartilages/the menisci and the cruciate ligaments.

CONCLUSIONS

The main advantages of the PD-weighted FRFSE sequence are the increase in contrast between fluid and non-fluid tissues and the time saved by using the procedure. However, in the absence of joint effusion, the PD-weighted FRFSE sequence generates a poorer contrast between the cartilage and meniscus, the cruciate ligaments and fat of the intercondylar fossa.

Growth of Amorphous and Crystalline Silicon by HR-CVD (Hydrogen Radical Enhanced CVD)

Systematic studies have been made on preparation of Si thin films from SiF4 under control over the flow of atomic hydrogens. The gas phase reactions taking place in the mixture of fragments (SiFn) resulting from plasma-induced dissociation and atomic hydrogens were widely investigated by a mass spectroscopy. Chemically active species,i.e., SiF2H and SiH2F were found as those related to the growth of films. The growth in the vicinity of substrates involves either endothermic or radical-enhanced reaction for the propagation of the three dimensional Si networks, accompaning release of terminators such as H and F. Accordingly, Si thin films with structures from amorphous to crystalline were obtained by controlling the flow of atomic hydrogen. A marked improvement in the hole-transport was established in the Si films containing hydrogen less than 5–6 at % due to the reduction in the tail states near the valence band.

Photo and Scanning Probe Lithography Using Alkylsilane Self-Assembled Monolayers

An organic film of a few nm in thickness was applied as a resist for photolithography and scanning probe lithography. This resist film was prepared on an oxide-covered Si substrate through chemisorption and spontaneous organization of organosilane molecules, e.g., n-octadecyltrimethoxysilane. The film belongs to a class of materials referred to as self-assembled monolayer (SAM). A SAM/Si sample was irradiated through a photomask with vacuum ultraviolet (VUV) light at a wavelength of 172 nm. The photomask image was transferred to the SAM through the decomposition of the SAM. Furthermore, we demonstrate nano-scale patterning of the SAM using an atomic force microscope (AFM) with an electrically conductive probe. The SAM was electrochemically degraded in the region where the AFM probe had been scanned. Both the photo-printed and AFM-genereated patterns were successfully transferred into the Si substrates based on wet chemical etching or on dry plasma etching. At present, using these VUV and AFM-based lithographies, we have succeeded in fabricating minute features of 2 μm and 20 nm in width, respectively.

Chemical characterization of the oligosaccharides in Bactrian camel (Camelus bactrianus) milk and colostrum

Bactrian camel milk and colostrum are commonly used as foods in Mongolia, whose people believe that these products promote human health. It has been hypothesized that milk oligosaccharides are biologically significant components of human milk, acting as receptor analogs that inhibit the attachment of pathogenic microorganisms to the colonic mucosa, and as prebiotics, which stimulate the growth of bifidobacteria within the infant colon. To evaluate their biological significance, we studied the oligosaccharides present in samples of Bactrian camel milk and colostrum. Using (1)H-nuclear magnetic resonance spectroscopy, we identified and characterized the following oligosaccharides of camel colostrum: Gal(β1-4)[Fuc(α1-3)]Glc (3-fucosyllactose), Gal(β1-3)Gal(β1-4)Glc (3'-galactosyllactose), Gal(β1-6)Gal(β1-4)Glc (6'-galactosyllactose), Neu5Ac(α2-3)Gal(β1-4)Glc (3'-sialyllactose), Neu5Ac(α2-6)Gal(β1-4)Glc (6'-sialyllactose), Neu5Ac(α2-3)Gal(β1-3)Gal(β1-4)Glc (sialyl-3'-galactosyllactose), Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)Glc (sialyllacto-N-tetraose c), Neu5Ac(α2-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyllacto-N-novopentaose a), Gal(β1-3)[Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyllacto-N-novopentaose b); and Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (monosialyllacto-N-neohexaose). The oligosaccharides in the mature camel milk were characterized as 3'-galactosyllactose, Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (lacto-N-novopentaose I), and 3'-sialyllactose.

Helicobacter bilis colonization of the biliary system in patients with pancreaticobiliary maljunction

BACKGROUND

Helicobacter bilis is considered to be a causative factor in the pathogenesis of biliary cancer. This study investigated the prevalence of H. bilis colonization of the biliary system of patients with pancreaticobiliary maljunction (PBM).

METHODS

Bile juice and biliary tissue samples were collected from 17 patients with PBM and 27 controls who had benign biliary disease without PBM. DNA extracted from each biliary sample was subjected to polymerase chain reaction (PCR) analysis for H. bilis and Helicobacter pylori.

RESULTS

PCR assays revealed that 12 of the 17 patients with PBM were positive for H. bilis DNA, compared with eight of 27 patients without PBM (P = 0.009). Among patients with PBM, H. bilis DNA was identified in six of eight children, including a 2-month-old infant, and in six of nine adults. The high prevalence of H. bilis DNA in the biliary system of patients with PBM was independent of age, sex, common bile duct dilatation, configuration of the pancreatic and bile ducts, and amylase activity in bile.

CONCLUSION

H. bilis colonization of the biliary system is extremely common in patients with PBM. This may point to a role in the pathogenesis of biliary cancer.

Helicobacter bilis colonization of the biliary system in patients with pancreaticobiliary maljunction

BACKGROUND

Helicobacter bilis is considered to be a causative factor in the pathogenesis of biliary cancer. This study investigated the prevalence of H. bilis colonization of the biliary system of patients with pancreaticobiliary maljunction (PBM).

METHODS

Bile juice and biliary tissue samples were collected from 17 patients with PBM and 27 controls who had benign biliary disease without PBM. DNA extracted from each biliary sample was subjected to polymerase chain reaction (PCR) analysis for H. bilis and Helicobacter pylori.

RESULTS

PCR assays revealed that 12 of the 17 patients with PBM were positive for H. bilis DNA, compared with eight of 27 patients without PBM (P = 0.009). Among patients with PBM, H. bilis DNA was identified in six of eight children, including a 2-month-old infant, and in six of nine adults. The high prevalence of H. bilis DNA in the biliary system of patients with PBM was independent of age, sex, common bile duct dilatation, configuration of the pancreatic and bile ducts, and amylase activity in bile.

CONCLUSION

H. bilis colonization of the biliary system is extremely common in patients with PBM. This may point to a role in the pathogenesis of biliary cancer.