484 research outputs found

    Immunocytochemical Phenotyping of Disseminated Tumor Cells in Bone Marrow by uPA Receptor and CK18: Investigation of Sensitivity and Specificity of an Immunogold/Alkaline Phosphatase Double Staining Protocol

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    Phenotyping of cytokeratin (CK) 18-positive cells in bone marrow is gaining increasing importance for future prognostic screening of carcinoma patients. Urokinase-type plasminogen activator receptor (uPA-R) is one example of a potential aggressive marker for those cells. However, a valid and reliable double staining method is needed. Using monoclonal antibodies against uPA-R and CK18, we modified an immunogold/alkaline phosphatase double staining protocol. UPA-R/CK18-positive tumor cell controls exhibited black uPA-R staining in 15–80 of cases and red CK18 staining in almost 100 of tumor cells. Isotype- and cross-matched controls were completely negative. Bone marrow from healthy donors was always CK18-negative. Reproducibility of CK18-positive cell detection was estimated in a series of specimens from 61 gastric cancer patients comparatively stained with the single alkaline phosphatase-anti-alkaline phosphatase (APAAP) and our double staining method (106 bone marrow cells/patient). In four cases, double staining could not reproduce CK18-positive cells. In 34 cases it revealed fewer or equal numbers, and in 23 cases more CK18-positive cells than the APAAP method. Overall quantitative analysis of detected cell numbers (838 in APAAP, range 1–280 in 106; double staining 808, range 0–253) demonstrated relative reproducibility of APAAP results by double staining of 97. Correlation of results between both methods was significant (p<0.001, linear regression). Sensitivity of double staining tested in logarithmic tumor cell dilutions was one CK18-positive cell in 300,000. Specific uPA-R staining was seen on CK18-positive cells in bone marrow from 29 of 61 patients, and also on single surrounding bone marrow cells. To test the specificity of this staining, bone marrow cytospins from 10 patients without tumor disease were stained for uPA-R with the APAAP method. uPA-R expression was confirmed in all 10 cases, with a mean of 6.5 uPA-R-positive cells in 1000 bone marrow cells (SEM 1.2). These results suggest that our double staining protocol is a sensitive, reproducible, and specific method for routine uPA-R phenotyping of disseminated CK18-positive cells in bone marrow of carcinoma patients

    Superconducting gap structure of the skutterudite LaPt4Ge12 probed by specific heat and thermal transport

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    We investigated the superconducting order parameter of the filled skutterudite LaPt4Ge12, with a transition temperature of Tc = 8.3 K. To this end, we performed temperature and magnetic-field dependent specific-heat and thermal-conductivity measurements. All data are compatible with a single superconducting s-wave gap. However, a multiband scenario cannot be ruled out. The results are discussed in the context of previous studies on the substitution series Pr1-xLaxPt4Ge12. They suggest compatible order parameters for the two end compounds LaPt4Ge12 and PrPt4Ge12. This is not consistent with a single s-wave gap in LaPt4Ge12 considering previous reports of unconventional and/or multiband superconductivity in PrPt4Ge12.Comment: 8 pages, 4 figure

    Effect of intracellular Ca2+ concentration on endothelin-1 secretion

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    AbstractThe role of intracellular free Ca2+ concentration ([Ca2+]i in cellular regulation of endothelin-(ET-1) secretion was investigated in cultured porcine aortic endothelial cells of first passage. Intracellular Ca2+ concentration were adjusted between 50 nM and 1 μM using EGTA and thapsigargin, respectively. ET-1 secretion was maximal at [Ca2+]i of 190–470 nM, and reduced at low (50 and 110 nM) and high (470 nM) [Ca2+]i. The Ca2+ ionophores A23187 and ionomycin (each 1 μM), both of which raise [Ca2+]i above 1 μM, also potently inhibited ET-1 secretion under basal and stimulated conditions. The A23187-induced reduction in ET-1 secretion was not affected by NG-nitro-l-arginine (0.1 mM). Our results provide evidence that basal ET-1 secretion is regulated by Ca2+ and that Ca2+ ionophores reduce ET-1 secretion due to the inhibitory effect of high [Ca2+]i

    Toward Nanowire Electronics

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    This paper discusses the electronic transport properties of nanowire field-effect transistors (NW-FETs). Four different device concepts are studied in detail: Schottky-barrier NW-FETs with metallic source and drain contacts, conventional-type NW-FETs with doped NW segments as source and drain electrodes, and, finally, two new concepts that enable steep turn-on characteristics, namely, NW impact ionization FETs and tunnel NW-FETs. As it turns out, NW-FETs are, to a large extent, determined by the device geometry, the dimensionality of the electronic transport, and the way of making contacts to the NW. Analytical as well as simulation results are compared with experimental data to explain the various factors impacting the electronic transport in NW-FETs

    Enabling people with diverse abilities to Participate in the Design of Digital Mapping Tools for Inclusive Community Planning in Germany

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    People with so-called intellectual disabilities are underrepresented in Citizen Science projects. The topic of urban health offers an extensive field of application for Citizen Science projects and digital methods have the potential to involve many, and diverse people. The DiMDiCi (Digital Mapping with Disabled Citizens) project integrates these three areas. The project investigates how the needs of people with so-called intellectual disabilities for movement and participation in (semi-)public space can be captured with the help of digital methods and integrated into municipal planning processes. Photovoice and digital maptables are used as barrier-sensitive digital methods and applications are further developed. Our goal is to develop methods with which more and other people can participate in society in general and in urban development and research in particular. DiMDiCi is a pilot project in the European COESO project and is being worked on jointly by the University of Applied Sciences in Bochum, the University of Twente, the Wittekindshof as an institution for people with disabilities and the city of Herne.</p

    Reliability of light microscopy and a computer-assisted replica measurement technique for evaluating the fit of dental copings

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    Abstract The aim of this in vitro study was to assess the reliability of two measurement systems for evaluating the marginal and internal fit of dental copings. Material and Methods: Sixteen CAD/CAM titanium copings were produced for a prepared maxillary canine. To modify the CAD surface model using different parameters (data density; enlargement in different directions), varying fit was created. Five light-body silicone replicas representing the gap between the canine and the coping were made for each coping and for each measurement method: (1) light microscopy measurements (LMMs); and (2) computer-assisted measurements (CASMs) using an optical digitizing system. Two investigators independently measured the marginal and internal fit using both methods. The inter-rater reliability [intraclass correlation coefficient (ICC)] and agreement [Bland-Altman (bias) analyses]: mean of the differences (bias) between two measurements [the closer to zero the mean (bias) is, the higher the agreement between the two measurements] were calculated for several measurement points (marginal-distal, marginal-buccal, axial-buccal, incisal). For the LMM technique, one investigator repeated the measurements to determine repeatability (intra-rater reliability and agreement). Results: For inter-rater reliability, the ICC was 0.848-0.998 for LMMs and 0.945-0.999 for CASMs, depending on the measurement point. Bland-Altman bias was −15.7 to 3.5 μm for LMMs and −3.0 to 1.9 μm for CASMs. For LMMs, the marginal-distal and marginal-buccal measurement points showed the lowest ICC (0.848/0.978) and the highest bias (-15.7 μm/-7.6 μm). With the intra-rater reliability and agreement (repeatability) for LMMs, the ICC was 0.970-0.998 and bias was −1.3 to 2.3 μm. Conclusion: LMMs showed lower interrater reliability and agreement at the marginal measurement points than CASMs, which indicates a more subjective influence with LMMs at these measurement points. The values, however, were still clinically acceptable. LMMs showed very high intra-rater reliability and agreement for all measurement points, indicating high repeatability

    Ontogenetic expression of thyroid hormone signaling genes: An in vitro and in vivo species comparison.

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    Thyroid hormone (TH) is essential for brain development. While disruption of TH signaling by environmental chemicals has been discussed as a mechanism of developmental neurotoxicity (DNT) for more than a decade, there remains a paucity of information linking specific TH disrupting chemicals to adverse neurodevelopmental outcomes. This data gap reflects, in part, the fact that the molecular machinery of TH signaling is complex and varies according to cell type and developmental time. Thus, establishing a baseline of the ontogenetic profile of expression of TH signaling molecules in relevant cell types is critical for developing in vitro and alternative systems-based models for screening TH disrupting chemicals for DNT. Here, we characterize the transcriptomic profile of molecules critical to TH signaling across three species-human, rat, and zebrafish-in vitro and in vivo across different stages of neurodevelopment. Our data indicate that while cultured human and rat neural progenitor cells, primary cultures of rat cortical cells, and larval zebrafish all express a fairly comprehensive transcriptome of TH signaling molecules, the spatiotemporal expression profiles as well as the responses to TH vary across species and developmental stages. The data presented here provides a roadmap for identifying appropriate in vitro and in simpler systems-based models for mechanistic studies and screening of chemicals that alter neurodevelopment via interference with TH action
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