Detection of Lead in the Carbon-Rich, Very Metal-Poor Star LP625-44: A Strong Constraint on s-Process Nucleosynthesis at Low Metallicity

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and Pb agrees well with a scaled solar system s-process component, while the lighter elements (Sr-Zr) are less abundant than Ba. The enhancement of s-process elements is interpreted as a result of mass transfer in a binary system from a previous AGB companion, an interpretation strongly supported by radial velocity variations of this system. The detection of Pb makes it possible, for the first time, to compare model predictions of s-process nucleosynthesis in AGB stars with observations of elements between Sr and Pb. The Pb abundance is significantly lower than the prediction of recent models (e.g., Gallino et al. 1998), which succeeded in explaining the metallicity dependence of the abundance ratios of light s-elements (Sr-Zr) to heavy ones (Ba-Dy) found in previously observed s-process-enhanced stars. This suggests that one should either (a) reconsider the underlying assumptions concerning the 13C-rich s-processing site (13C-pocket) in the present models, or (b) investigate alternative sites of s-process nucleosynthesis in very metal-poor AGB stars.Comment: 10 pages, 3 figures, Astrophysical Journal Letters, in pres

Pattern formation of reaction-diffusion system having self-determined flow in the amoeboid organism of Physarum plasmodium

The amoeboid organism, the plasmodium of Physarum polycephalum, behaves on the basis of spatio-temporal pattern formation by local contraction-oscillators. This biological system can be regarded as a reaction-diffusion system which has spatial interaction by active flow of protoplasmic sol in the cell. Paying attention to the physiological evidence that the flow is determined by contraction pattern in the plasmodium, a reaction-diffusion system having self-determined flow arises. Such a coupling of reaction-diffusion-advection is a characteristic of the biological system, and is expected to relate with control mechanism of amoeboid behaviours. Hence, we have studied effects of the self-determined flow on pattern formation of simple reaction-diffusion systems. By weakly nonlinear analysis near a trivial solution, the envelope dynamics follows the complex Ginzburg-Landau type equation just after bifurcation occurs at finite wave number. The flow term affects the nonlinear term of the equation through the critical wave number squared. Contrary to this, wave number isn't explicitly effective with lack of flow or constant flow. Thus, spatial size of pattern is especially important for regulating pattern formation in the plasmodium. On the other hand, the flow term is negligible in the vicinity of bifurcation at infinitely small wave number, and therefore the pattern formation by simple reaction-diffusion will also hold. A physiological role of pattern formation as above is discussed.Comment: REVTeX, one column, 7 pages, no figur

Evidence for a companion to BM Gem, a silicate carbon star

Balmer and Paschen continuum emission as well as Balmer series lines of P Cygni-type profile from H_gamma through H_23 are revealed in the violet spectra of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell (`silicate carbon star') observed with the high dispersion spectrograph (HDS) on the Subaru telescope. The blue-shifted absorption in the Balmer lines indicates the presence of an outflow, the line of sight velocity of which is at least 400 km s^-1, which is the highest outflow velocity observed to date in a carbon star. We argue that the observed unusual features in BM Gem are strong evidence for the presence of a companion, which should form an accretion disk that gives rise to both an ionized gas region and a high velocity, variable outflow. The estimated luminosity of ~0.2 (0.03-0.6) L_sun for the ionized gas can be maintained by a mass accretion rate to a dwarf companion of ~10^-8 M_sun yr^-1, while ~10^-10 M_sun yr^-1 is sufficient for accretion to a white dwarf companion. These accretion rates are feasible for some detached binary configurations on the basis of the Bond-Hoyle type accretion process. We concluded that the carbon star BM Gem is in a detached binary system with a companion of low mass and low luminosity. However, we are unable to determine whether this companion object is a dwarf or a white dwarf. The upper limits for binary separation are 210 AU and 930 AU for a dwarf and a white dwarf, respectively. We also note that the observed features of BM Gem mimic those of Mira (omi Cet), which may suggest actual similarities in their binary configurations and circumstellar structures.Comment: 11 pages, 2 figures, 1 table, accepted for publication in Ap

Autophagy in the Thymic Epithelium Is Dispensable for the Development of Self-Tolerance in a Novel Mouse Model

The thymic epithelium plays critical roles in the positive and negative selection of T cells. Recently, it was proposed that autophagy in thymic epithelial cells is essential for the induction of T cell tolerance to self antigens and thus for the prevention of autoimmune diseases. Here we have tested this hypothesis using mouse models in which autophagy was blocked specifically in epithelial cells expressing keratin 14 (K14), including the precursor of thymic epithelial cells. While the thymic epithelial cells of mice carrying the floxed Atg7 gene (ATG7 f/f) showed a high level of autophagy, as determined by LC3 Western blot analysis and fluorescence detection of the recombinant green fluorescent protein (GFP)-LC3 reporter protein on autophagosomes, autophagy in the thymic epithelium was efficiently suppressed by deletion of the Atg7 gene using the Cre-loxP system (ATG7 f/f K14-Cre). Suppression of autophagy led to the massive accumulation of p62/sequestosome 1 (SQSTM1) in thymic epithelial cells. However, the structure of the thymic epithelium as well as the organization and the size of the thymus were not altered in mutant mice. The ratio of CD4 to CD8-positive T cells, as well as the frequency of activated (CD69+) CD4 T cells in lymphoid organs, did not differ between mice with autophagy-competent and autophagy-deficient thymic epithelium. Inflammatory infiltrating cells, potentially indicative of autoimmune reactions, were present in the liver, lung, and colon of a similar fraction of ATG7 f/f and ATG7 f/f K14-Cre mice. In contrast to previously reported mice, that had received an autophagy-deficient thymus transplant, ATG7 f/f K14-Cre mice did not suffer from autoimmunity-induced weight loss. In summary, the results of this study suggest that autophagy in the thymic epithelium is dispensable for negative selection of autoreactive T cells

Pathophysiological analysis of detrusor overactivity following partial bladder outlet obstruction

　Introduction: Detrusor overactivity (DO) following partial bladder outlet obstruction (PBOO) is a common urological condition in humans, with 50-70% patients with PBOO complicated with DO. The pathological mechanisms of DO following PBOO are largely unknown, but inflammatory changes may play a key role. We hypothesized that inflammation is important in the earlier pathophysiological phase before overproduction of oxidative stress in DO following PBOO. Therefore, we investigated the relationships among bladder function, ischemia, oxidative stress and inflammation in DO following PBOO in PBOO model mice.　Materials and Methods: C57BL/6J male mice aged 10 to 15 weeks were used in the study. PBOO model mice were created surgically by ligation of the proximal urethra with 5-0 nylon suture under inhalation anesthesia. Sham-operated mice were used as controls. Pathophysiological changes in the bladder at 1, 3 and 5 weeks after creation of the PBOO model mice were compared with those in sham-operated mice using functional, histological, biochemical and immunohistochemical analyses.　Results: Functional analysis using a pressure flow study showed increased maximum detrusor pressure at 1 week and DO from 3 to 5 weeks after creation of the PBOO model. Histological analysis using hematoxylin-eosin and Masson-Trichrome staining showed greater invasion of inflammatory cells and fibrosis in PBOO model mice compared with sham-operated mice at 3 and 5 weeks. Inflammatory cells were mainly present in interstitial tissue, and fibrosis gradually infiltrated from interstitial tissue to the muscular layer. Ischemia analysis showed significantlyincreased HIF-1α in PBOO model mice at all time points. Oxidative stress analysis indicated significantly increased levels of ROS from 1 week and 8-OHdG from 3weeks in PBOO model mice. An inflammation-related proteome assay showed high levels of colony stimulating factor (CSF) family proteins at 1 week and IL-2, IL-3, IL-17A, IL-23, MMP-3, MMP-9 and periostin from 3 to 5 weeks in PBOO model mice.　Conclusions: Oxidative stress and inflammatory changes showed contemporaneous increase in pathophysiology of detrusor overactivity following partial bladder outlet obstruction. Especially, CSF family and ROS changes are showed in the early stage, and might be a predict marker in the pathophysiology of DO following PBOO at the early stage

Preventive effect of indoleamine 2,3-dioxygenase 1 inhibition on lipopolysaccharide-induced prostatitis

　Introduction and Objectives: Bacterial infections are the main cause of acute prostatitis and are treated with appropriate antimicrobial therapy. However, approximately 5% of patients continue to have inflammatory symptoms even after receiving antibacterial therapy, leading to refractory conditions. Bacterial prostatitis requires additional therapy, focusing on inflammatory changes. Indoleamine 2,3-dioxygenase 1 (IDO1) catalysis is the first rate-limiting step of tryptophan metabolism. IDO1 is expressed in the prostate and plays a key role in the immune response. As the first step in investigating the relationship between acute prostatitis and IDO1, we investigated the preventive effect of IDO1 inhibition on lipopolysaccharide (LPS)- induced prostatitis using IDO knockout (Ido1 −/−) mice in this study.　Materials and Methods: The study used Ido1 −/− and wild-type (Ido1 +/+) C57BL/6J malemice aged 10–15 weeks. LPS Escherichia coli O26 (100μg/PBS, 100μL) was administered transurethrally into the lower urinary tract to create a mouse model of LPS-induced prostatitis. The prostates were removed 1, 3, 5, and 7 days after creating the model mice. Histological, immunohistochemical, and biochemical analyses were used to compare the preventive effect in Ido1 −/− mice compared with that in Ido1+/+ mice.　Results: HE staining showed suppression of ductal destruction following infiltration of inflammatory cells in Ido1 −/− mice compared with Ido1 +/+ mice. The enzyme-linked immunosorbent assay (ELISA) method was used for kynurenine pathway analysis, which showed significantly maintained tryptophan levels and decreased L-kynurenine levels in Ido1 −/− mice compared to Ido1 +/+ mice. The IDO1 assay in Ido1 +/+ mice showed significantly increased levels during all observation periods after creating the model compared with that under normal conditions. Immunofluorescent staining using five types of cytokines and chemokines (IL-2, IL-4, IL-17, CCL2, and CCL3) related to the pathophysiology of acute prostatitis showed decreased expression of these cytokines and chemokines in Ido1 -/- mice compared with Ido1 +/+ mice. Inflammation-related proteome assays showed decreased levels of IL-1β, IL-4, IL-5, IL-6, IL-17, CCL2, CCL3, CXCL1, CXCL11, and tissue inhibitor of matrix metalloproteinases (TIMP)-1 in Ido1 −/− mice compared with Ido1 −/− mice during all observation periods after model creation.　Conclusions: IDO1 is involved in LPS-induced prostatitis through cytokines and chemokines. IDO1 inhibition contributes to the prevention of LPS-induced prostatitis. IDO1 inhibition has the potential to serve as an additional therapy for acute prostatitis

In epithelial cancers, aberrant COL17A1 promoter methylation predicts its misexpression and increased invasion

Background: Metastasis is a leading cause of death among cancer patients. In the tumor microenvironment, altered levels of extracellular matrix proteins, such as collagens, can facilitate the first steps of cancer cell metastasis, including invasion into surrounding tissue and intravasation into the blood stream. However, the degree of misexpression of collagen genes in tumors remains understudied, even though this knowledge could greatly facilitate the development of cancer treatment options aimed at preventing metastasis. Methods: We systematically evaluate the expression of all 44 collagen genes in breast cancer and assess whether their misexpression provides clinical prognostic significance. We use immunohistochemistry on 150 ductal breast cancers and 361 cervical cancers and study DNA methylation in various epithelial cancers. Results: In breast cancer, various tests show that COL4A1 and COL4A2 overexpression and COL17A1 (BP180, BPAG2) underexpression provide independent prognostic strength (HR = 1.25, 95% CI = 1.17–1.34, p = 3.03 × 10; HR = 1.18, 95% CI = 1.11–1.25, p = 8.11 × 10; HR = 0.86, 95% CI = 0.81–0.92, p = 4.57 × 10; respectively). Immunohistochemistry on ductal breast cancers confirmed that the COL17A1 protein product, collagen XVII, is underexpressed. This strongly correlates with advanced stage, increased invasion, and postmenopausal status. In contrast, immunohistochemistry on cervical tumors showed that collagen XVII is overexpressed in cervical cancer and this is associated with increased local dissemination. Interestingly, consistent with the opposed direction of misexpression in these cancers, the COL17A1 promoter is hypermethylated in breast cancer and hypomethylated in cervical cancer. We also find that the COL17A1 promoter is hypomethylated in head and neck squamous cell carcinoma, lung squamous cell carcinoma, and lung adenocarcinoma, in all of which collagen XVII overexpression has previously been shown. Conclusions: Paradoxically, collagen XVII is underexpressed in breast cancer and overexpressed in cervical and other epithelial cancers. However, the COL17A1 promoter methylation status accurately predicts both the direction of misexpression and the increased invasive nature for five out of five epithelial cancers. This implies that aberrant epigenetic control is a key driver of COL17A1 gene misexpression and tumor cell invasion. These findings have significant clinical implications, suggesting that the COL17A1 promoter methylation status can be used to predict patient outcome. Moreover, epigenetic targeting of COL17A1 could represent a novel strategy to prevent metastasis in patients