1,720,966 research outputs found
Evidence for the existence of ganglioside molecules on Pneumocystis carinii from human lungs.
No full textThis study was undertaken to assess whether glycolipid antigens (particularly gangliosides) are associated with Pneumocystis carinii obtained from human lungs. Gangliosides were extracted, purified in high performance thin-layer chromatography and stained with resorcinol. Two resorcinol-positive bands, co-migrating with GM1 and GD1a were demonstrated, suggesting the existence of ganglioside molecules on P. carinii. No resorcinol-positive bands were revealed in the pulmonary control tissue. In addition, an antiserum obtained from rabbits immunized with P. carinii antigen reacted with gangliosides GM1 and GD1a, as revealed by a dot immunobinding assay. This reactivity was inhibited by first incubating the antiserum with ganglioside micelles. Furthermore, anti-glycosphingolipid antibodies (aGM1) reacted with the bands of 200 and 55 kDa of P. carinii antigen. These results suggest that ganglioside antigens expressed on P. carinii can trigger specific immune responses
GM3 AS A TARGET OF ANTI-LYMPHOCYTIC GANGLIOSIDE ANTIBODIES IN AIDS PATIENTS
No full textIgG antibodies reacting with the GM3-comigrating band extracted from pooled AIDS lymphocytes were detected in 33.3% of AIDS patients sera, in 8% of asymptomatic anti-HIV-positive subjects, in none of the sera obtained from asymptomatic anti-HIV-negative drug abusers, from patients with acute B and chronic C hepatitis, and from healthy donors. All positive sera reacted selectively with the GM3-comigrating band obtained from AIDS lymphocytes but not with the corresponding band from normal lymphocytes. The lymphocytic ganglioside autoantigen was revealed as GM3. In addition, two main data were shown: (a) AIDS lymphocytes have an increased concentration of GM3 and (b) the ceramide of AIDS lymphocytic GM3 has a different percentual composition of fatty acids in contrast to control cells. It is suggested that these quantitative and qualitative changes might be responsible for the appearance of circulating anti-lymphocytic GM3 antibodies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Anticardiolipin and anti-beta(2)-GPI are two distinct populations of autoantibodies
No full textThis study has been undertaken to assess whether anticardiolipin and anti-beta 2-GPI are two distinct populations of (auto)antibodies, and to clarify whether the beta 2-GPI region critical for phospholipid binding is also crucial for anti-beta 2-GPI reactivity. Fourteen of the 62 anticardiolipin (aCL) ELISA positive sera (22.6%) were positive for anti-beta 2-GPI by immunoblotting, 42 (67.7%) for aCL using TLC immunostaining. IgG fractions from 5 sera gave the same anticardiolipin reactivity detected by TLC immunostaining in the corresponding sera. All anti-beta 2-GPI-positive sera were reactive with the phenylthiocarbamyl derivative of the protein, indicating that binding of phenylisothiocyanate with lysine residues does not modify the molecule antigenicity. In addition, incubation of IgG fractions with the phospholipid binding site did not modify reactivity with beta 2-GPI. These findings demonstrate that: a) "true" antiphospholipid antibodies are detectable in patients' sera; b) aCL and anti-beta 2-GPI have a different immunological profile; c) the beta 2-GPI phospholipid-binding site is not the region recognized by the antibodies
Detection of antiphospholipid antibodies by immunostaining on thin layer chromatography plates.
No full textThere is increasing interest in the role of antiphospholipid antibodies in the so-called 'antiphospholipid antibody syndrome' (APS). The two major methods currently employed for detecting the autoantibodies are the solid phase ELISA and the LAI test (inhibition of phospholipid dependent coagulation assay). In our study we have tested the possibility of detecting antiphospholipid antibodies by immunostaining on thin layer chromatography (TLC) plates, since this technique permits the use of pure phospholipid molecules as antigen. Sera were collected from 20 patients with SLE without APS, 20 patients with APS, 20 anti-HIV positive subjects, ten patients with signs of APS but antiphospholipid negative (ELISA), 20 patients with syphilis and 40 matched blood donors. Results showed that only 72.3% of sera containing detectable levels of aCL antibodies in solid phase ELISA were also positive for aCL in TLC immunostaining; these discrepancies may be due to the presence of antibodies reacting with a protein complexed with phospholipid (beta(2)-glycoprotein-I) or, alternatively, to the different antigenic presentation of phospholipids on chromatograms compared to the surface of microtitre wells. Furthermore, aCL monoclonal antibody CAL-3, as well as nine sera positive for aCL, also reacted with PS and PE. Previous absorption of these sera with CL micelles completely abolished the reactivity with PS and PE, demonstrating cross-reactivity among these three phospholipids. In conclusion, our findings reveal that TLC immunostaining is more specific, but less sensitive, than ELISA for the detection of antiphospholipid antibodies in human sera
Inhibition of protein S by autoantibodies in patients with acquired protein S deficiency
No full textThis study was undertaken to analyze antibodies to protein S (PS) in patients with an acquired PS deficiency. Plasma from symptomatic patients with acquired (n = 14) or congenital (n = 10) PS deficiency and LD healthy donors was screened for PS antibodies by immunoblotting and for anti-phospholipid antibodies. PS antibodies (IgG) were detected in five of the patients with acquired PS deficiency. These antibodies belonged to the G1 and G4 immunoglobulin subclasses. IgG fractions from the same 5 patients were shown to inhibit PS activity. The inhibition of PS activity by the 5 IgG fractions was shown to be time- and dose-dependent and was abolished following incubation with purified PS, while no effect was found after absorption with cardiolipin micelles. In addition, anticardiolipin monoclonal or human purified antibodies, failed to exert significant PS inhibition. These findings demonstrate that anti-PS antibodies are able to inhibit PS activity and that this is independent of anti-phospholipid antibodies. Given the clinical features of the patients, these antibodies should be regarded as an expression of the broad autoimmune syndrome involving the phospholipid-binding plasma proteins
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