1,720,974 research outputs found
In vitro undetectable PT and Fibrinogen (and in vivo?)
No full textA 81 aged woman came to E.R. of Trieste University Hospital with a traumatic head injury. Blood cells count, liver enzymes and other parameters were normal, but with a photometric clot detection method PT and PT-derived Fibrinogen were undetectable, Fibrinogen-Clauss gave different results (157 to 357 mg/dL) and aPTT-Ratio was normal (0.96). When the instrument detection performance was improved, PT was normal and PT-derived Fibrinogen detectable, but Fibrinogen-Clauss was still very unsteady (352/294/558 mg/dL). When a mixing test was performed with normal pool plasma, PT was corrected, PT-derived Fibrinogen was very low (80 mg/dL) and Fibrinogen-Clauss resulted 360 mg/dL. Fibrinogen-Antigen was 368 mg/dL by a nephelometric immunoassay. In another Lab with a different optical analyzer, PT and aPTT yielded the same results, Fibrinogen-Clauss was 557 mg/dL with 35 IU/ml Thrombin reagent (and a very steep clot formation curve), but 113 mg/dL with 15 IU/ml Thrombin reagent (and a normal curve). With an electromechanical clot detection method, PT-INR and aPTT-Ratio were normal (0.88 and 0.96 respectively), Fibrinogen-Clauss was normal (400 mg/dL) but unsteady. However in a few days our patient healed up perfectly; she declared that her sister had the same performance when she was referred to another Hospital for a check-up, nonetheless they never had any severe bleeding in their life.
Samples from our patient’s son and daughter were taken and resulted completely normal for coagulation tests.
We hypothetized:
1) a too fast Thrombin formation and/or Fibrinogen consumption, as shown by steep coagulation curves without a stable plateau;
2) an excessive thrombin formation, (in preliminary studies, however, G20210A mutation was absent and F1+2 were normal);
3) a dysfibrinogenemia, (to be studied).
Further studies for Endogenous Thrombin Potential about thrombin ipothesis and for genetical pattern about fibrinogen molecule are needed to clarify this case
Cirrhotic thrombocytopenia is a multifactorial condition: evidence of reduced platelet production and incresed platelet destruction
No full textBackground: Thrombocytopenia is a common manifestation of liver cirrhosis (LC), but the underlying mechanism is not fully understood. The purpose of our work was to evaluate the platelet kinetics in LC of different etiology by examining platelet production and destruction.
Patients: 91 consecutive LC patients (36 HCV, 49 alcoholics, 15 HBV) were enrolled in the study. As controls, 25 cases with idiopathic thrombocytopenic purpura (ITP), 10 with aplastic anemia (AA), and 40 healthy blood donors were studied.
Methods: Plasma thrombopoietin (TPO) was measured by ELISA. Absolute reticulated platelet (RP) count was determined by Thiazole Orange method. Plasma glycocalicin (GC) was measured by monoclonal antibodies. Platelet associated and serum circulating antiplatelet antibodies were detected by flow cytometry. The B-cell monoclonality in the PBMC were performed by isotype-specific immunoglobulin fingerprinting.
Results: The serum TPO was significantly (p<0.0005) lower in the patients with LC (29.9 ± 18.1 pg/ml) than in normals (82.3 ± 47.6 pg/ml). The GC index was 1.96 ± 1.40 in HCV+ LC (p<0.0005 vs. normals 0.9 ± 0.2), 1.79 ± 1.51 in alcoholic LC (p<0.006) and 1.71 ± 1.69 in HBV + LC (p<0.006). In the patients affected by ITP, the GC index was 12.9 ± 4.4 (p<0.000002). The absolute levels of RP were 4.233 ± 2.367 109/L in alcoholic LC (p<0.0000000012 vs normals) 4.996 ± 3.143 x 109/L in HBV+ LC (p<0.006) and 6.629 ± 7.409 x 109/L in HCV+LC (p<0.005). The prevalence of platelet-associated and circulating anti-platelet antibodies was higher in HCV+ LC than in healthy subjects (p<0.0064), than in alcoholic LC (p<0.018) and than in HBV+ LC (p<0.0001). The B-cell monoclonality was found in 8 (27%) of the HCV-positive patients, whereas no monoclonality was found in HBV (p<0.004) or alcoholic patients (p<0.003).
Conclusions: Patients with LC present a decreased plasma TPO, an accelerated platelet turnover and a low platelet production. These findings indicate that cirrhotic thrombocytopenia is a multifactorial condition, involving both increased platelet clearance and impaired thrombopoiesis. The HCV-LC is characterized by an increased prevalence of autoimmune phenomena, including anti-platelet antibodies and, as consequence, a platelet turnover more accelerated than in HBV or alcoholic LC
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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