172 research outputs found
A clear separation of foraging areas between two neighboring colonies of Adelie Penguins observed in a year of extensive sea ice cover
The Tenth Symposium on Polar Science/Ordinary sessions : [OB] Polar Biology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc
M. Novel magnetic behavior of multidimensional organic polymer synthesized by cycloaddition reaction
We report the magnetic properties of a novel organic polymer. The material gives the large saturation magnetization (0.15G/g) at room temperature. Electron spin resonance (ESR) revealed a ferrimagnetic character, i. e., the existence of "exchange resonance branch" with extremely large g-value. The new organic polymer with large saturation magnetization can be stoichiometrically and reproducibly synthesized under ambient conditions and expected to be useful for practical applications
Multiple inflammatory cytokine-productive ThyL-6 cell line established from a patient with thymic carcinoma
Thymic epithelial cells can produce many kinds of cytokines, and interleukin (IL)-6-producing thymic carcinoma cases have been reported. However, a cytokine-producing human thymic tumor cell line has not previously been established. In this paper, we report a novel, multiple inflammatory cytokine-productive cell line that was established from a patient with thymic carcinoma. This cell line, designated ThyL-6, positively expressed epithelial membrane antigen, cytokeratins, vimentin intermediate filament and CD5, although hematological markers were not present in the cells. Cytokine antibody array analysis showed that the cells secreted several cytokines including IL-1α, IL-6, IL-8, RANTES, soluble TNFα-receptor 1, VEGF and CTLA into the culture medium. The addition of ThyL-6-cultured supernatant supported the growth of human myeloma ILKM-3 cells, which require the presence of IL-6 in the culture medium for the maintenance of cell growth, suggesting that the secreted IL-6 from ThyL-6 cells was biologically active. Chromosome analysis demonstrated that ThyL-6 cells had complex karyotype anomalies, including der(16)t(1;16); the latter has been recognized in thymic squamous cell carcinoma and thymic sarcomatoid carcinoma cases, as well as in several other kinds of malignancies. Heterotransplantation of the cells into nude mice showed tumorigenesis with neutrophil infiltration and liquefactive necrosis. These findings suggest that ThyL-6 cells will provide us with a new experimental tool for investigating not only the pathogenesis, biological behavior, chromo-somal analysis and therapeutic reagents of human thymic carcinoma, but also for studying cytokine-chemokine network systems
Spectral Energy Distributions of Dusty Galaxies
We present a SED model of dusty galaxies, in which the equation of radiative
transfer is solved by assuming spherical symmetry. The temperature fluctuation
of very small dust particles is calculated consistently with the radiative
transfer. The adopted dust model consists of graphite and silicate grains and
PAHs, whose relative fractions are determined for each MW, LMC and SMC type
extinction curve. This model allows us to derive the intrinsic SEDs of stellar
populations embedded in dusty ISM, which are very important indicators for the
age of stellar populations. Therefore, the evolutionary phase of starburst
galaxies which have frequently very dusty ISM can be investigated with this SED
model. We show that the SEDs of Arp220 and M82 can both be explained by the
same single stellar population, despite the significant differences in the SEDs
and the infrared luminosities. The apparent difference between their SEDs is
mainly caused by the difference in the optical depth. In contrast, the SED of
prototypical star-forming ERO, HR10, indicates that this galaxy is relatively
old comparing to Arp220 and M82. It is found that, in the case of optically
thin limit like elliptical galaxies, the optical depth cannot be inferred only
from the SED, due to a degeneracy between the optical depth, galactic size, and
the spatial distribution of dust; the latter two are important for estimating
the average temperature of dust grains in elliptical galaxies. When the
observed size of elliptical galaxies is adopted for the model geometry, SEDs
can be used to constrain the spatial distribution of dust in elliptical
galaxies.Comment: 36 pages, 21 figures, submitted to PAS
Age and Dust Degeneracy for Starburst Galaxies Solved?
A spectral evolution model of galaxies that includes both stellar and dust
effects is newly built. xApplying the model to 22 nearby starburst galaxies, we
have shown that far infrared luminosity of galaxies helps to break the
age-dustiness degeneracy. We have derived a unique solution of age and the
dustiness for each starburst galaxy. The resulting starburst ages and optical
depths are in the range and , respectively. The result is robust and is almost independent of model
assumptions such as dust distributions, extinction curves, and burst strengths.
With the rapidly growing sensitivity of submillimeter detectors, it should
become possible in the near future to determine the age and of
star-forming galaxies at redshifts and beyond. Accurate estimates
of for Lyman-break galaxies and high-z galaxies might require a
substantial revision of the previously claimed picture of star formation
history over the Hubble time.Comment: Latex (aas2pp4) 15 pages, 1 table, 6 figures. Accepted for Ap
Evolutionary SED diagnostics of starburst galaxies: signature of bimodality
We construct an evolutionary spectral energy distribution (SED) model of a
starburst region, from the ultraviolet to submillimetre wavelengths. This model
allows us to derive the star formation rate, optical depth by dust and apparent
effective radius of starburst regions at various wavelengths; as a result, the
intrinsic surface brightness of starburst regions can be derived. Using this
SED model, we analyse 16 UV-selected starburst galaxies and 10 ultraluminous
infrared galaxies. The derived star formation rates and optical depths are
compared with emission line measurements and found to be consistent. The
derived apparent effective radii are also consistent with observations. From
the SED analysis, we find a bimodal property of the star formation rate with
the optical depth and the compactness of stellar distributions. While mild
starbursts have a limiting intrinsic surface brightness L(bol) x r_e^{-2} ~
10^{12} Lsun kpc^{-2}, intense starbursts tend to be more heavily obscured and
concentrated within a characteristic scale of r_e ~ 0.3 kpc. We suggest that
the mild starbursts can be triggered by a self-gravitating disc instability in
which feedback is effective in the shallow gravitational potential. On the
other hand, the intense starbursts can be induced via an external dynamical
perturbation like galaxy merging, in which feedback is less effective due to
the deep gravitational potential attained by the large gas concentration within
the central starburst region.Comment: 22 pages, 15 figures, accepted for publication in MNRA
17β-Hydroxysteroid Dehydrogenase Type 2 Expression Is Induced by Androgen Signaling in Endometrial Cancer.
Endometrial cancer is one of the most common female pelvic cancers and has been considered an androgen-related malignancy. Several studies have demonstrated the anti-cell proliferative effect of androgen on endometrial cancer cells; however, the mechanisms of the anti-cancer effect of androgen remain largely unclear. 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2), which catalyzes the conversion of E2 to E1, is known to be upregulated by androgen treatment in breast cancer cells. In this study, we therefore focused on the role of androgen on estrogen dependence in endometrial cancer. Dihydrotestosterone (DHT) was found to induce 17β-HSD2 mRNA and protein expression in HEC-1B endometrial cancer cells. DHT could also inhibit cell proliferation of HEC-1B when induced by estradiol treatment. In 19 endometrioid endometrial adenocarcinoma (EEA) tissues, intratumoral DHT concentration was measured by liquid chromatography/electrospray tandem mass spectrometry and was found to be significantly correlated with 17β-HSD2 immunohistochemical status. We further examined the correlations between 17β-HSD2 immunoreactivity and clinicopathological parameters in 53 EEA tissues. 17β-HSD2 status was inversely associated with the histological grade, clinical stage, and cell proliferation marker Ki-67, and positively correlated with progesterone receptor expression. 17β-HSD2 status tended to be positively associated with androgen receptor status. In 53 EEA cases, the 17β-HSD2-positive group tended to have better prognosis than that for the negative group with respect to progression-free survival and endometrial cancer-specific survival. These findings suggest that androgen suppresses the estrogen dependence of endometrial cancer through the induction of 17β-HSD2 in endometrial cancer
Prolactin inhibits osteoclastic activity in the goldfish scale: A novel direct action of prolactin in teleosts
In teleosts, prolactin is involved in calcium regulation, but its role in scale/bone metabolism Is unclear. Using the in-vitro system with goldfish scales developed recently, we explored the effects of teleost prolactin, growth hormone, and somatolactin on osteoclasts and osteoblasts. Addition of prolactin at concentrations of 0.01-100 ng/ml reduced osteoclastic activity, partly via osteoclast apoptosis, after 6-18 h incubation. Conversely, growth hormone and somatolactin at a concentration of 100 ng/ml increased osteoclastic activity after 18 h incubation, indicating the specificity of the inhibitory effect of prolactin on osteoclastic activity. On the other hand, these three hormones promoted osteoblastic activity at concentrations of 10-100 ng/ml. The results from this study are the first demonstration of direct effects of prolactin on scale/bone metabolism and osteoclastic activity in a teleost. © 2008 Zoological Society of Japan
Molecular Identification of t(w5): Vps52 Promotes Pluripotential Cell Differentiation Through Cell-Cell Interactions
After implantation, pluripotent epiblasts are converted to embryonic ectoderm through cell-cell interactions that significantly change the transcriptional and epigenetic networks. An entree to understanding this vital developmental transition is the t(w5) mutation of the mouse t complex. This mutation produces highly specific defects in the embryonic ectoderm before gastrulation, leading to death of the embryonic ectoderm. Using a positional cloning approach, we have now identified the mutated gene, completing a decades-long search. The gene, vacuolar protein sorting 52 (Vps52), is a mouse homolog of yeast VPS52 that is involved in the retrograde trafficking of endosomes. Our data suggest that Vps52 acts in extraembryonic tissues to support the growth and differentiation of embryonic ectoderm via cell-cell interactions. It is also required in the formation of embryonic structures at a later stage of development, revealing hitherto unknown functions of Vps52 in the development of a multicellular organism.NSFCellular and Molecular Biolog
Prevention of esophageal strictures after endoscopic submucosal dissection
Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have recently been accepted as less invasive methods for treating patients with early esophageal cancers such as squamous cell carcinoma and dysplasia of Barrett\u27s esophagus. However, the large defects in the esophageal mucosa often cause severe esophageal strictures, which dramatically reduce the patient\u27s quality of life. Although preventive endoscopic balloon dilatation can reduce dysphagia and the frequency of dilatation, other approaches are necessary to prevent esophageal strictures after ESD. This review describes several strategies for preventing esophageal strictures after ESD, with a particular focus on anti-inflammatory and tissue engineering approaches. The local injection of triamcinolone acetonide and other systemic steroid therapies are frequently used to prevent esophageal strictures after ESD. Tissue engineering approaches for preventing esophageal strictures have recently been applied in basic research studies. Scaffolds with temporary stents have been applied in five cases, and this technique has been shown to be safe and is anticipated to prevent esophageal strictures. Fabricated autologous oral mucosal epithelial cell sheets to cover the defective mucosa similarly to how commercially available skin products fabricated from epidermal cells are used for skin defects or in cases of intractable ulcers. Fabricated autologous oralmucosal- epithelial cell sheets have already been shown to be safe
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