16,710 research outputs found

    Keratin 6a marks mammary bipotential progenitor cells that can give rise to a unique tumor model resembling human normal-like breast cancer.

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    Progenitor cells are considered an important cell of origin of human malignancies. However, there has not been any single gene that can define mammary bipotential progenitor cells, and as such it has not been possible to use genetic methods to introduce oncogenic alterations into these cells in vivo to study tumorigenesis from them. Keratin 6a is expressed in a subset of mammary luminal epithelial cells and body cells of terminal end buds. By generating transgenic mice using the Keratin 6a (K6a) gene promoter to express tumor virus A (tva), which encodes the receptor for avian leukosis virus subgroup A (ALV/A), we provide direct evidence that K6a(+) cells are bipotential progenitor cells, and the first demonstration of a non-basal location for some biopotential progenitor cells. These K6a(+) cells were readily induced to form mammary tumors by intraductal injection of RCAS (an ALV/A-derived vector) carrying the gene encoding the polyoma middle T antigen. Tumors in this K6a-tva line were papillary and resembled the normal breast-like subtype of human breast cancer. This is the first model of this subtype of human tumors and thus may be useful for preclinical testing of targeted therapy for patients with normal-like breast cancer. These observations also provide direct in vivo evidence for the hypothesis that the cell of origin affects mammary tumor phenotypes

    Gender and sexuality

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    The electroluminescent decay mechanism of rare-earth ions in OLEDs based on a terbium complex

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    The organic light-emitting diodes (OLEDs) based on terbium (Tb) complexes show sharp green emission spectrum with excellent color purity. However, the brightness of Tb-OLEDs is generally weak. Here, the electroluminescent (EL) decay mechanism of TB-OLEDs is studied by arbitrarily using tris-(1-phenyl-3-methyl-4-isobutyryl-5-pyrozolone)-bis(triphenyl phosphine oxide) terbium as the emitting layer. The device shows high EL efficiency at low current density but rapid reduction of device efficiency at higher current density. The transient EL is investigated for understanding the decay process of excited Tb 3+ ions. Together with theoretical studies, exciton quenching is proposed to explain the decay of the Tb-OLEDs which is important for optimizing and engineering the material and device structures. The EL from the mixed layer of the Tb and europium (Eu) complexes is also studied. We find that the EL performance and transient decay of the excited Tb ions are modified by energy transfer from Tb to Eu in the OLEDs. © 2007 IEEE.published_or_final_versio

    Many Commercially Available Antibodies for Detection of CHOP Expression as a Marker of Endoplasmic Reticulum Stress Fail Specificity Evaluation

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    Endoplasmic reticulum (ER) stress contributes to beta cell death in type 2 diabetes (T2DM). ER stress is characterized by increased level of ER stress markers such as C/EBP homologous protein (CHOP). Activation of CHOP leads to its translocation into the nucleus, where it induces cell death. We previously reported nuclear CHOP in pancreatic sections from T2DM, but not T1DM, and in human islet amyloid polypeptide (IAPP) transgenic rodent pancreatic sections. These studies underscore the importance of studying nuclear CHOP. We have observed inconsistency in the detection of CHOP antibodies reported in the literature and also in our own experiments. To investigate the specificity of CHOP antibodies, we first induced ER stress by tunicamycin in rat insulinoma (INS) cells and prepared nuclear and cytoplasmic fractions. Then we examined CHOP expression by Western blotting and immunocytochemistry using seven commercially available CHOP antibodies in INS cells and human IAPP (h-IAPP) transgenic rodent pancreatic tissue. These studies show that three commercially available CHOP antibodies out of seven tested were non-specific. In conclusion, we give recommendations for CHOP antibody selection and methods to verify CHOP antibody specificity. Also, we propose that the authors report the catalog and lot numbers of the CHOP antibodies used

    Characterization and Comparison of 2 Distinct Epidemic Community-Associated Methicillin-Resistant Staphylococcus aureus Clones of ST59 Lineage.

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    Sequence type (ST) 59 is an epidemic lineage of community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) isolates. Taiwanese CA-MRSA isolates belong to ST59 and can be grouped into 2 distinct clones, a virulent Taiwan clone and a commensal Asian-Pacific clone. The Taiwan clone carries the Panton-Valentine leukocidin (PVL) genes and the staphylococcal chromosomal cassette mec (SCCmec) VT, and is frequently isolated from patients with severe disease. The Asian-Pacific clone is PVL-negative, carries SCCmec IV, and a frequent colonizer of healthy children. Isolates of both clones were characterized by their ability to adhere to respiratory A549 cells, cytotoxicity to human neutrophils, and nasal colonization of a murine and murine sepsis models. Genome variation was determined by polymerase chain reaction of selected virulence factors and by multi-strain whole genome microarray. Additionally, the expression of selected factors was compared between the 2 clones. The Taiwan clone showed a much higher cytotoxicity to the human neutrophils and caused more severe septic infections with a high mortality rate in the murine model. The clones were indistinguishable in their adhesion to A549 cells and persistence of murine nasal colonization. The microarray data revealed that the Taiwan clone had lost the ø3-prophage that integrates into the β-hemolysin gene and includes staphylokinase- and enterotoxin P-encoding genes, but had retained the genes for human immune evasion, scn and chps. Production of the virulence factors did not differ significantly in the 2 clonal groups, although more α-toxin was expressed in Taiwan clone isolates from pneumonia patients. In conclusion, the Taiwan CA-MRSA clone was distinguished by enhanced virulence in both humans and an animal infection model. The evolutionary acquisition of PVL, the higher expression of α-toxin, and possibly the loss of a large portion of the β-hemolysin-converting prophage likely contribute to its higher pathogenic potential than the Asian-Pacific clone

    Enhancing resilience by reducing critical load loss via an emergent trading framework considering possible resources isolation under typhoon

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    Leveraging distributed resources to enhance distribution network (DN) resilience is an effective measure in response to natural disasters. However, the willingness and economy of distributed resources are typically ignored. To address this issue, this paper proposes an emergent trading framework that uses parking lots (PLs) as resources to provide power support to critical loads (CLs) in a blackout due to typhoons. In this trading framework, an evolutionary Stackelberg game-based trading model is established to consider maximizing all stakeholders' economic benefits, considering possible resources isolation under typical fault scenarios caused by typhoons, and a benefit allocation mechanism is proposed for all stakeholders to motivate all stakeholders to participate in the trading. This framework allows that critical loads could reduce their load loss, parking lots could receive adequate compensation to stimulate them to participate in the trading, and distribution utility could ensure its economic benefits. Furthermore, an iterative evolutionary-Stackelberg solution set-up is applied to obtain the equilibria of the proposed framework. Simulation results on the modified IEEE 69-bus test system and IEEE 123-bus test system reveal the validity of the proposed method

    Enabling effective tree exploration using visual cues

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    © 2018 Elsevier Ltd This article presents a new interactive visualization for exploring large hierarchical structures by providing visual cues on a node link tree visualization. Our technique provides topological previews of hidden substructures with three types of visual cues including simple cues, tree cues and treemap cues. We demonstrate the visual cues on Degree-of-Interest Tree (DOITree) due to its familiar mapping, its capability of providing multiple focused nodes, and its dynamic rescaling of substructures to fit the available space. We conducted a usability study with 28 participants that measured completion time and accuracy across five different topology search tasks. The simple cues had the fastest completion time across three of the node identification tasks. The treemap cues had the highest rate of correct answers on four of the five tasks, although only reaching statistical significance for two of these. As predicted, user ratings demonstrated a preference for the easy to understand tree cues followed by the simple cue, despite this not consistently reflected in performance results

    High expression rates of human islet amyloid polypeptide induce endoplasmic reticulum stress-mediated beta cell apoptosis, a characteristic of humans with type 2 but not type 1 diabetes

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    [[abstract]]OBJECTIVE—Endoplasmic reticulum (ER) stress–induced apoptosis may be a common cause of cell attrition in diseases characterized by misfolding and oligomerisation of amyloidogenic proteins. The islet in type 2 diabetes is characterized by islet amyloid derived from islet amyloid polypeptide (IAPP) and increased β-cell apoptosis. We questioned the following: 1) whether IAPP-induced β-cell apoptosis is mediated by ER stress and 2) whether β-cells in type 2 diabetes are characterized by ER stress. RESEARCH DESIGN AND METHODS—The mechanism of IAPP-induced apoptosis was investigated in INS-1 cells and human IAPP (HIP) transgenic rats. ER stress in humans was investigated by β-cell C/EBP homologous protein (CHOP) expression in 7 lean nondiabetic, 12 obese nondiabetic, and 14 obese type 2 diabetic human pancreata obtained at autopsy. To assure specificity for type 2 diabetes, we also examined pancreata from eight cases of type 1 diabetes. RESULTS—IAPP induces β-cell apoptosis by ER stress in INS-1 cells and HIP rats. Perinuclear CHOP was rare in lean nondiabetic (2.6 ± 2.0%) and more frequent in obese nondiabetic (14.6 ± 3.0%) and obese diabetic (18.5 ± 3.6%) pancreata. Nuclear CHOP was not detected in lean nondiabetic and rare in obese nondiabetic (0.08 ± 0.04%) but six times higher (P < 0.01) in obese diabetic (0.49 ± 0.17%) pancreata. In type 1 diabetic pancreata, perinuclear CHOP was rare (2.5 ± 2.3%) and nuclear CHOP not detected. CONCLUSIONS—ER stress is a mechanism by which IAPP induces β-cell apoptosis and is characteristic of β-cells in humans with type 2 diabetes but not type 1 diabetes. These findings are consistent with a role of protein misfolding in β-cell apoptosis in type 2 diabetes

    The human initiator is a distinct and abundant element that is precisely positioned in focused core promoters.

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    DNA sequence signals in the core promoter, such as the initiator (Inr), direct transcription initiation by RNA polymerase II. Here we show that the human Inr has the consensus of BBCA+1BW at focused promoters in which transcription initiates at a single site or a narrow cluster of sites. The analysis of 7678 focused transcription start sites revealed 40% with a perfect match to the Inr and 16% with a single mismatch outside of the CA+1 core. TATA-like sequences are underrepresented in Inr promoters. This consensus is a key component of the DNA sequence rules that specify transcription initiation in humans

    Intranasal immunisation with Ag85B peptide 25 displayed on Lactococcus lactis using the PilVax platform induces antigen-specific B- and T-cell responses.

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    Mycobacterium tuberculosis (Mtb) remains a global epidemic despite the widespread use of BCG. Consequently, novel vaccines are required to facilitate a reduction in Mtb morbidity and mortality. PilVax is a peptide delivery strategy for the generation of highly specific mucosal immune responses and is based on the food-grade bacterium Lactococcus lactis that is used to express selected peptides engineered within the Streptococcus pyogenes M1T1 pilus, allowing for peptide amplification, stabilisation, and enhanced immunogenicity. In the present study, the dominant T cell epitope from the Mtb protein Ag85B was genetically engineered into the pilus backbone subunit and expressed on the surface of L. lactis. Western blot and flow cytometry confirmed formation of pilus containing the peptide DNA sequence. B cell responses in intranasally vaccinated mice were analysed by ELISA while T cell responses were analysed by flow cytometry. Serum titres of peptide specific IgG and IgA were detected, confirming vaccination produced antibodies against the cognate peptide. Peptide-specific IgA was also detected across several mucosal sites sampled. Peptide-specific CD4+ T cells were detected at levels similar to those of mice immunised with BCG. PilVax immunisation resulted in an unexpected increase in the numbers of CD3+ CD4- CD8- (double negative, DN) T cells in the lungs of vaccinated mice. Analysis of cytokine production following stimulation with the cognate peptide showed the major cytokine producing cells to be CD4+ T cells and DN T cells. This study provides insight into the antibody and peptide specific cellular immune responses generated by PilVax vaccination and demonstrates the suitability of this vaccine for conducting a protection study
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