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[en] Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs) play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF) is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment
[en] We study the amplification of the electromagnetic fluctuations, and the production of 'seeds' for the cosmic magnetic fields, in a class of string cosmology models whose scalar and tensor perturbations reproduce current observations and satisfy known phenomenological constraints. We find that the condition of efficient seeds production can be satisfied and compatible with all constraints only in a restricted region of parameter space, but we show that such a region has significant intersections with the portions of parameter space where the produced background of relic gravitational waves is strong enough to be detectable by aLIGO/Virgo and/or by eLISA.
[en] The decision to use a new enzyme linked immunosorbent assay (ELISA) technique to diagnose infectious diseases in veterinary medicine must be based on careful validation and standardization of the test to ensure a high level of accuracy according to defined criteria. In particular, laboratories performing diagnostic tests related to control, surveillance or eradication programmes need to take care in producing accurate and precise test results in their daily routine. To ensure this, laboratories should have an acceptable level of organization and management that provides sufficient guarantee of producing reliable test results. Measures should include the performance of a well documented internal quality control (QC) programme in which internal control samples are calibrated against national or international reference standards where possible. The internal QC programme should be focused on test precision (random and systemic errors) and, if possible, also on test accuracy (correctness of test results). It is of importance that reference or specialized laboratories make primary or secondary reference standard samples available to diagnostic laboratories in order to enable careful calibration of internal control samples. An objective of monitoring test accuracy is the participation in (inter)national external QC programmes organized by independent specialized and/or authorized reference laboratories. When possible, diagnostic laboratories should participate in such external QC programmes. Some aspects of the QC programme as used in veterinary immune diagnostic laboratories in the Netherlands are described. (author)
[en] Assay validation requires a series of inter-related processes. Assay validation is an experimental process: reagents and protocols are optimized by experimentation to detect the analyte with accuracy and precision. Assay validation is a relative process: its diagnostic sensitivity and diagnostic specificity are calculated relative to test results obtained from reference animal populations of known infection/exposure status. Assay validation is a conditional process: classification of animals in the target population as infected or uninfected is conditional upon how well the reference animal population used to validate the assay represents the target population; accurate predictions of the infection status of animals from test results (PV+ and PV-) are conditional upon the estimated prevalence of disease/infection in the target population. Assay validation is an incremental process: confidence in the validity of an assay increases over time when use confirms that it is robust as demonstrated by accurate and precise results; the assay may also achieve increasing levels of validity as it is upgraded and extended by adding reference populations of known infection status. Assay validation is a continuous process: the assay remains valid only insofar as it continues to provide accurate and precise results as proven through statistical verification. Therefore, the work required for validation of diagnostic assays for infectious diseases does not end with a time-limited series of experiments based on a few reference samples rather, to assure valid test results from an assay requires constant vigilance and maintenance of the assay, along with reassessment of its performance characteristics for each unique population of animals to which it is applied. (author)
[en] The solar surface oscillations observed in the Crimean Astrophysical Observatory (CrAO) at the frequency 104.1890 μHz and in the Solar and Heliospheric Observatory (SoHO) at 220.72 μHz are considered as a result of existence of Compact Clumps of Dark Matter (CCDM) at orbits near the solar surface. These CCDM have to emit Gravitational Waves (GW) which are estimated to be the most intensive ones expected in the vicinity of the Earth and can be easily detected in the near future by means of the Evolved Laser Interferometer Space Antenna (eLISA). In addition to CCDMCrAO and CCDMSoHO some other CCDM may exist in the solar structure. It is shown that GW radiated by most of these CCDM could be detected by eLISA even if the respective solar surface oscillations are too small to be observed.
[en] AXL is a well-characterized, protumorigenic receptor tyrosine kinase that is highly expressed and activated in numerous human carcinomas and sarcomas, including aggressive subtypes of liposarcoma. However, the role of AXL in the pathogenesis of well-differentiated (WDLPS), dedifferentiated (DDLPS), and pleomorphic liposarcoma (PLS) has not yet been determined. Immunohistochemical analysis of AXL expression was conducted on two tissue microarrays containing patient WDLPS, DDLPS, and PLS samples. A panel of DDLPS and PLS cell lines were interrogated via western blot for AXL expression and activity and by ELISA for growth arrest-specific 6 (GAS6) production. AXL knockdown was achieved by siRNA or shRNA. The effects of AXL knockdown on cell proliferation, migration, and invasion were measured in vitro. In addition, AXL shRNA-containing DDLPS cells were assessed for their tumor-forming capacity in vivo. In this study, we determined that AXL is expressed in a subset of WDLPS, DDLPS, and PLS patient tumor samples. In addition, AXL and its ligand GAS6 are expressed in a panel of DDLPS and PLS cell lines. We show that the in vitro activation of AXL via stimulation with exogenous GAS6 resulted in a significant increase in cell proliferation, migration, and invasion in DDLPS and PLS cell lines. Transient knockdown of AXL resulted in attenuation of these protumorigenic phenotypes in vitro. Stable AXL knockdown not only decreased migratory and invasive characteristics of DDLPS and PLS cells in vitro but also significantly diminished tumorigenicity of two dedifferentiated liposarcoma xenograft models in vivo. Our results suggest that AXL signaling contributes to the aggressiveness of DDLPS and PLS, and that AXL is therefore a potential therapeutic target for treatment of these rare, yet devastating tumors
[en] The customary diagnostic methods of today have been developed in industrialized countries. High costs for personnel resulted in a trend towards automation and prefabricated test kits. Consequently, these techniques are not sufficiently adapted to local conditions in developing countries, where, as a rule, skilled and ancillary staff is available whereas foreign currency reserves for purchasing laboratory equipment and material from abroad are rather limited. Furthermore, the training of personnel from developing countries has usually been oriented towards thenon-transferable standards and methods of industrialized countries. This leads to a long term dependence of the diagnostic services on external funding. A diagnostic technology adapted to the specific local conditions of developing countries is needed to overcome this situation. The project activities concentrate on serological diagnostic work. Here, basic knowledge of the common diagnostic techniques and their set-up for specific diseases, methods for the production of related reagents (antigens, antibodies, conjugates, complement, etc.) and cleaning procedures for the reuse of 'one way' plastic material is spread by training programmes, specific publications and information leaflets. For two of the more complex test procedures, the most frequently quoted prescribed test for international trade, CFT, and the increasingly important ELISA (OIE, Manual of Standards for Diagnostic Techniques, Paris, 1992), we have calculated the cost reduction potential of adaptation through self-production of reagents and reuse of plastic materials. Material costs per microtitre test plate for the diagnosis of brucellosis can be reduced from US $3.79 to 0.82 for CFT and from US $3.88 to 1.13 for ELISA. In comparison, commercial ELISA kits cost about US $80 to 90 per plate (e.g. Bommeli, IDEXX, Boehringer)
[en] The technique of radioimmunoassay (RIA), introduced by Yalow and Berson rapidly became established as a routine analytical method. Eight years later Miles and Hales proposed an alternative technique, the immunoradiometric assay (IRMA), citing its theoretical superiority over RIA. It is only in this decade, however, that these advantages have been demonstrated and IRMAs have begun to appear in routine clinical use
[en] Quality checks are essential to assure production of high quality plants and to have end-users confidence. Quality standards require the establishment of suitable tests to maintain quality control. The choice of explant source, freedom of the donor plant from viruses, disease causing fungi, bacteria, viroids, phytoplasmas, vigour and conformity of the variety, and elimination of somaclonal variants are critical for maintaining plant quality. Variety identification by proper labeling at all stages is essential to ensure varietal identity. (author)