3,462 research outputs found

    Persistence of hepatic hepatitis B virus after serological clearance of HBsAG with autologous peripheral stem cell transplantation

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    Delayed clearance of hepatitis B surface antigen was previously reported in a 38 year old woman after high dose chemotherapy with autologous peripheral blood stem cell rescue. Sixteen months later, this patient remained hepatitis B surface antigen negative, hepatitis B surface anti-body positive, and serum hepatitis B DNA negative by polymerase chain reaction. Serial liver biopsies (one at hepatitis B e antigen positive stage, one at hepatitis B e antibody positive stage, and one at hepatitis B surface antigen negative and hepatitis B surface antibody positive stage) showed a gradual resolution of the inflammatory activity with loss of hepatitis B e antigen and then hepatitis B surface antigen in the serum. However, the degree of fibrosis, though mild, remained the same. With the serological clearance of hepatitis B surface antigen, a small amount of hepatitis B virus DNA was still detectable in the nuclei of liver cells.published_or_final_versio

    Sexual reproduction and genetic polymorphism within the cosmopolitan marine diatom Pseudo-nitzschia pungens.

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    Different clades belonging to the cosmopolitan marine diatom Pseudo-nitzschia pungens appear to be present in different oceanic environments, however, a 'hybrid zone', where populations of different clades interbreed, has also been reported. Many studies have investigated the sexual reproduction of P. pungens, focused on morphology and life cycle, rather than the role of sexual reproduction in mixing the genomes of their parents. We carried out crossing experiments to determine the sexual compatibility/incompatibility between different clades of P. pungens, and examined the genetic polymorphism in the ITS2 region. Sexual reproduction did not occur only between clades II and III under any of experimental temperature conditions. Four offspring strains were established between clade I and III successfully. Strains established from offspring were found interbreed with other offspring strains as well as viable with their parental strains. We confirmed the hybrid sequence patterns between clades I and III and found novel sequence types including polymorphic single nucleotide polymorphisms (SNPs) in the offspring strains. Our results implicate that gene exchange and mixing between different clades are still possible, and that sexual reproduction is a significant ecological strategy to maintain the genetic diversity within this diatom species

    Ectodysplasin signalling deficiency in mouse models of Hypohidrotic Ectodermal Dysplasia leads to middle ear and nasal pathology

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    Hypohidrotic ectodermal dysplasia (HED) results from mutation of the EDA, EDAR or EDARADD genes and is characterized by reduced or absent eccrine sweat glands, hair follicles and teeth, and defective formation of salivary, mammary and craniofacial glands. Mouse models with HED also carry Eda, Edar or Edaradd mutations and have defects that map to the same structures. Patients with HED have ear, nose and throat disease, but this has not been investigated in mice bearing comparable genetic mutations. We report that otitis media, rhinitis and nasopharyngitis occur at high frequency in Eda and Edar mutant mice and explore the pathogenic mechanisms related to glandular function, microbial and immune parameters in these lines. Nasopharynx auditory tube glands fail to develop in HED mutant mice and the functional implications include loss of lysozyme secretion, reduced mucociliary clearance and overgrowth of nasal commensal bacteria accompanied by neutrophil exudation. Heavy nasopharynx foreign body load and loss of gland protection alters the auditory tube gating function and the auditory tubes can become pathologically dilated. Accumulation of large foreign body particles in the bulla stimulates granuloma formation. Analysis of immune cell populations and myeloid cell function shows no evidence of overt immune deficiency in HED mutant mice. Our findings using HED mutant mice as a model for the human condition support the idea that ear and nose pathology in HED patients arises as a result of nasal and nasopharyngeal gland deficits, reduced mucociliary clearance and impaired auditory tube gating function underlies the pathological sequelae in the bulla

    Suppression of tumorigenesis and metastasis of hepatocellular carcinoma by shRNA interference targeting on homeoprotein Six1

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    We previously demonstrated that the overexpression of homeoprotein Six1 in hepatocellular carcinoma (HCC) patients is associated with venous infiltration, advanced pathologic tumor metastasis (pTNM) stage and poor overall survival rate (Ng et al. Br J Cancer 2006;95:1050-5). In this study, short hairpin RNA (shRNA) interference approach was used to suppress the expression of Six1 in a metastatic HCC cell line MHCC97L. Stable transfectant MHCC97L-shSix1 carrying Six1-specific shRNA plasmid was established to downregulate Six1 expression to about 40% when compared with MHCC97L-Control. In vitro functional assays demonstrated that the growth rate and proliferation ability of MHCC97L-shSix1 cells were markedly decreased. Moreover, significant decrease of cell motility and invasiveness were observed in MHCC97L-shSix1 cells. Data from in vivo xenograft tumorigenesis model demonstrated that the size of tumor in MHCC97L-shSix1 group was dramatically reduced. Experimental and spontaneous metastasis models indicated that targeting Six1 suppression noticeably reduced the pulmonary metastasis in MHCC97L-shSix1 group. To identify Six1-regulated targets, cDNA microarray was employed to compare the expression profiles of MHCC97L-Control and MHCC97L-shSix1 cells. Twenty-eight downregulated and 24 upregulated genes with known functions were identified in MHCC97L-shSix1. The functions of these target genes are involved in diverse biological activities. Our data suggest that Six1 may be involved in regulation of proliferation and invasiveness of HCC; thus targeting suppression of Six1 is a viable option for treating HCC patients. © 2009 UICC.postprin

    Modification of upper-ocean temperature structure by subsurface mixing in the presence of strong salinity stratification

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    Author Posting. © The Oceanography Society, 2016. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 29, no. 2 (2016): 62–71, doi:10.5670/oceanog.2016.39.The Bay of Bengal has a complex upper-ocean temperature and salinity structure that is, in places, characterized by strong salinity stratification and multiple inversions in temperature. Here, two short time series from continuously profiling floats, equipped with microstructure sensors to measure subsurface mixing, are used to highlight implications of complex hydrography on upper-ocean heat content and the evolution of sea surface temperature. Weak mixing coupled with the existence of subsurface warm layers suggest the potential for storage of heat below the surface mixed layer over relatively long time scales. On the diurnal time scale, these data demonstrate the competing effects of surface heat flux and subsurface mixing in the presence of thin salinity-stratified mixed layers with temperature inversions. Pre-existing stratification can amplify the sea surface temperature response through control on the vertical extent of heating and cooling by surface fluxes. In contrast, subsurface mixing entrains relatively cool water during the day and relatively warm water during the night, damping the response to daytime heating and nighttime cooling at the surface. These observations hint at the challenges involved in improving monsoon prediction at longer, intraseasonal time scales as models may need to resolve upper-ocean variability over short time and fine vertical scales.This work was funded by Office of Naval Research grants N00014-14-1-0236 (ELS, JNM), N00014-13-1-0483 (DLR), N00014-13-1- 0453 (JTF), and N00014-12-1-0938 (SKV, AG)

    Efimov physics beyond three particles

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    Efimov physics originally refers to a system of three particles. Here we review recent theoretical progress seeking for manifestations of Efimov physics in systems composed of more than three particles. Clusters of more than three bosons are tied to each Efimov trimer, but no independent Efimov physics exists there beyond three bosons. The case of a few heavy fermions interacting with a lighter atom is also considered, where the mass ratio of the constituent particles plays a significant role. Following Efimov's study of the (2+1) system, the (3+1) system was shown to have its own critical mass ratio to become Efimovian. We show that the (4+1) system becomes Efimovian at a mass ratio which is smaller than its sub-systems thresholds, giving a pure five-body Efimov effect. The (5+1) and (6+1) systems are also discussed, and we show the absence of 6- and 7-body Efimov physics there

    Suppression of liver tumor growth and metastasis by adiponectin in nude mice through inhibition of tumor angiogenesis and downregulation of rho kinase/IFN-inducible protein 10/matrix metalloproteinase 9 signaling

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    Purpose: We aimed to investigate the effects of adiponectin on liver cancer growth and metastasis and explore the underlying mechanisms. Experimental Design: An orthotopic liver tumor nude mice model with distant metastatic potential was applied. Either Ad-adiponectin (1 × 10 8; treatment group) or Ad-luciferase (control group) was injected via portal vein after tumor implantation. Tumor growth and metastasis were monitored by Xenogen In vivo Imaging System. Hepatic stellate cell activation by α-smooth muscle actin staining, microvessel density by CD34 staining, macrophage infiltration in tumor tissue, and cell signaling leading to invasion, migration [Rho kinase (ROCK), IFN-inducible protein 10 (IP10), and matrix metalloproteinase 9], and angiogenesis [vascular endothelial growth factor (VEGF) and angiopoietin 1] were also compared. Tumor-nontumor margin was examined under electron microscopy. Direct effects of adiponectin on liver cancer cells and endothelial cells were further investigated by a series of functional studies. Results: Tumor growth was significantly inhibited by adiponectin treatment, accompanied by a lower incidence of lung metastasis. Hepatic stellate cell activation and macrophage infiltration in the liver tumors were suppressed by adiponectin treatment, along with decreased microvessel density. The treatment group had less Ki-67-positive tumor cells and downregulated protein expression of ROCK1, proline-rich tyrosine kinase 2, and VEGF. Tumor vascular endothelial cell damage was found in the treatment group under electron microscopy. In vitro functional study showed that adiponectin not only downregulated the ROCK/IP10/VEGF signaling pathway but also inhibited the formation of lamellipodia, which contribute to cell migration. Conclusion: Adiponectin treatment significantly inhibited liver tumor growth and metastasis by suppression of tumor angiogenesis and downregulation of the ROCK/IP10/matrix metalloproteinase 9 pathway. ©2010 AACR.postprin
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