Antigen p57/Kip2 as a potential negative regulator of human astrocytoma growth

This study was performed to determine the relationship between p57/Kip2 and the growth of human astrocytomas. Immunohistochemical staining for p57/Kip2, p53, p16, and Ki67 antigen was performed on paraffin-embedded tissue specimens obtained from 36 patients with astrocytoma. Expression of p57/Kip2, p53, p16, and Ki67 antigen was generally increased in association with the astrocytoma tumor grade. Expression of p16 was higher in patients whose tumors express p57/Kip2 in greater than 10% of tumor cells (p < 0.05). Expression of p53 also tended to be higher, but not to a statistically significant extent, in patients whose tumors express p57/Kip2 in greater than 10% of tumor cells. These findings suggest that p57/Kip2 inhibits the growth of human astrocytomas, and may function in parallel with p16 and p53. However, p57/Kip2 is, by itself, insufficient to arrest the cellular proliferation of human astrocytomas.ArticleJOURNAL OF CLINICAL NEUROSCIENCE. 16(12):1615-1618 (2009)journal articl

The dwarf phenotype of the Arabidopsis acl5 mutant is suppressed by a mutation in an upstream ORF of a bHLH gene

Loss-of-function mutants of the Arabidopsis thaliana ACAULIS 5 (ACL5) gene, which encodes spermine synthase, exhibit a severe dwarf phenotype. To elucidate the ACL5-mediated regulatory pathways of stem internocle elongation, we isolated four suppressor of acaulis (sac) mutants that reverse the acl5 dwarf phenotype. Because these mutants do not rescue the dwarfism of known phytohormone-related mutants, the SAC genes appear to act specifically on the ACL5 pathways. We identify the gene responsible for the dominant sac51-d mutant, which almost completely suppresses the acl5 phenotype. sac51-d disrupts a short upstream open reading frame (uORF) of SAC51, which encodes a bHLH-type transcription factor. Our results indicate that premature termination of the uORF in sac51-d results in an increase in its own transcript level, probably as a result of an increased translation of the main ORF. We suggest a model in which ACL5 plays a role in the translational activation of SAC51, which may lead to the expression of a subset of genes required for stem elongation

Phenotype Analysis and Quantification of Proliferating Cells in the Cortical Gray Matter of the Adult Rat

In intact adult mammalian brains, there are two neurogenic regions: the subependymal zone and the subgranular layer of the hippocampus. Even outside these regions, small numbers of proliferating precursors do exist. Many studies suggest that the majority of these are oligodendrocyte precursors that express NG2, a chondroitin sulfate proteoglycan, and most of the residual proliferating cells seem to be endothelial cells. However, it is still unclear whether NG2-immunonegative proliferating precursors are present, because previous studies have neglected their possible existence. In this study, we systematically analyzed the phenotypes of the proliferating cells in the intact adult rat cortical gray matter. We improved our techniques and carefully characterized the proliferating cells, because there were several problems with identifying and quantifying the proliferating cells: the detection of NG2-expressing cells was dependent on the fixation condition; there were residual proliferating leukocytes in the blood vessels; and two anti-NG2 antibodies gave rise to different staining patterns. Moreover, we used two methods, BrdU and Ki67 immunostaining, to quantify the proliferating cells. Our results strongly suggest that in the intact adult cerebral cortical gray matter, there were only two types of proliferating cells: the majority were NG2-expressing cells, including pericytes, and the rest were endothelial cells

First Detection of 12CO (1--0) Emission from Two Narrow-Line Seyfert 1 Galaxies

In order to investigate how the growth of galactic bulges progresses with the growth of central black holes (BHs), we observed molecular gas (fuel for the coming star formation) in possibly young active galaxies, narrow-line Seyfert 1 galaxies (NLS1s). We present the results of radio observations of 12CO(1--0) using the Nobeyama Millimeter Array (with 2--4 kpc spatial resolution) for two FIR-bright NLS1s, yielding the first detection of their CO emission. Corresponding molecular--gas masses M(H2) of (1-3) X 109 Msun are the 2nd and 4th largest ones among NLS1s. By estimating dynamical masses and bulge masses M(bulge) for these two NLS1s using CO channel map and CO line widths, we found M(H2) amount to 0.13--0.35 of these masses. Taking account the star formation efficiency (~ 0.1), the increase in M(bulge) in those NLS1s in the near future (~< 10^{7.5} yr) is expected not to be a huge fraction (1--5% of the preexisting stars). Bulge growth may have finished before BH growth, or bulge--BH coevolution may proceed with many, occasional discrete events, where one coevolution event produces only a small amount of mass growth of BHs and of bulges. We also discuss the ratios of star-formation rate--to--gas accretion rate onto BHs, finding that two NLS1s have very small ratios (~ 1) compared with the M(bulge)/M(BH) ratios found in active and inactive galaxies (~ 700). This huge difference suggests either the non-overlapped coevolution, long star formation duration or temporarily high accretion rate during NLS1 phase.Comment: 29 pages, 8 figures, Accepted for publication in The Astrophysical Journa

Dense Molecular Gas Associated with the Circumnuclear Star Forming Ring in the Barred Spiral Galaxy NGC 6951

We present high resolution (3" - 5") observations of CO(1-0) and HCN(1-0) emission from the circumnuclear star forming ring in the barred spiral galaxy NGC 6951, a host of a type-2 Seyfert, using the Nobeyama Millimeter Array and 45 m telescope. We find that most of the HCN emission is associated with the circumnuclear ring, where vigorous star formation occurs. The HCN to CO integrated intensity ratio is also enhanced in the star forming ring; the peak value of HCN/CO ratio is 0.18, which is comparable to the ratio in the starbursts NGC 253 and M82. The formation mechanism of dense molecular gas has been investigated. We find that the shocks along the orbit crowding do not promote the formation of the dense molecular gas effectively but enhance the presence of low density GMCs. Instead, gravitational instabilities of the gas can account for the dense molecular gas formation. The HCN/CO ratio toward the Seyfert nucleus of NGC 6951 is a rather normal value (0.086), in contrast with other Seyferts NGC 1068 and M51 where extremely high HCN/CO value of ~ 0.5 have been reported.Comment: 33 pages, 17 figures, to appear in the Astrophysical Journa

Active and inactive microaneurysms identified and characterized by structural and angiographic optical coherence tomography

Purpose: To characterize flow status within microaneurysms (MAs) and quantitatively investigate their relations with regional macular edema in diabetic retinopathy (DR). Design: Retrospective, cross-sectional study. Participants: A total of 99 participants, including 23 with mild nonproliferative DR (NPDR), 25 with moderate NPDR, 34 with severe NPDR, 17 with proliferative DR. Methods: In this study, 3x3-mm optical coherence tomography (OCT) and OCT angiography (OCTA) scans with a 400x400 sampling density from one eye of each participant were obtained using a commercial OCT system. Trained graders manually identified MAs and their location relative to the anatomic layers from cross-sectional OCT. Microaneurysms were first classified as active if the flow signal was present in the OCTA channel. Then active MAs were further classified into fully active and partially active MAs based on the flow perfusion status of MA on en face OCTA. The presence of retinal fluid near MAs was compared between active and inactive types. We also compared OCT-based MA detection to fundus photography (FP) and fluorescein angiography (FA)-based detection. Results: We identified 308 MAs (166 fully active, 88 partially active, 54 inactive) in 42 eyes using OCT and OCTA. Nearly half of the MAs identified straddle the inner nuclear layer and outer plexiform layer. Compared to partially active and inactive MAs, fully active MAs were more likely to be associated with local retinal fluid. The associated fluid volumes were larger with fully active MAs than with partially active and inactive MAs. OCT/OCTA detected all MAs found on FP. While not all MAs seen with FA were identified with OCT, some MAs seen with OCT were not visible with FA or FP. Conclusions: Co-registered OCT and OCTA can characterize MA activities, which could be a new means to study diabetic macular edema pathophysiology

Detection of the Far-infrared [O III] and Dust Emission in a Galaxy at Redshift 8.312: Early Metal Enrichment in the Heart of the Reionization Era

We present the Atacama Large Millimeter/submillimeter Array (ALMA) detection of the [O III] 88 $\mu$m line and rest-frame 90 $\mu$m dust continuum emission in a Y-dropout Lyman break galaxy (LBG), MACS0416_Y1, lying behind the Frontier Field cluster MACS J0416.1-2403. This [O III] detection confirms the LBG with a spectroscopic redshift of $z = 8.3118 \pm 0.0003$, making this object one of the furthest galaxies ever identified spectroscopically. The observed 850 $\mu$m flux density of $137 \pm 26$ $\mu$Jy corresponds to a de-lensed total infrared (IR) luminosity of $L_{\rm IR} = (1.7 \pm 0.3) \times 10^{11} L_{\odot}$ if assuming a dust temperature of $T_{\rm dust} = 50$ K and an emissivity index of $\beta = 1.5$, yielding a large dust mass of $4 \times 10^6 M_{\odot}$. The ultraviolet-to-far IR spectral energy distribution modeling where the [O III] emissivity model is incorporated suggests the presence of a young ($\tau_{\rm age} \approx 4$ Myr), star-forming (SFR $\approx 60 M_{\odot}$ yr$^{-1}$), moderately metal-polluted ($Z \approx 0.2 Z_{\odot}$) stellar component with a mass of $M_{\rm star} = 3 \times 10^8 M_{\odot}$. An analytic dust mass evolution model with a single episode of star-formation does not reproduce the metallicity and dust mass in $\tau_{\rm age} \approx 4$ Myr, suggesting a pre-existing evolved stellar component with $M_{\rm star} \sim 3 \times 10^9 M_{\odot}$ and $\tau_{\rm age} \sim 0.3$ Gyr as the origin of the dust mass.Comment: Accepted by ApJ. 18 pages, 10 figures, 5 table