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Infection and IL-6 are independent risk factors for a poor functional outcome from ischemic stroke
No full textBackground: Infections cause an inflammatory response that may activate the
endothelial cells lining blood vessels. Infections affect stroke outcome but the
mechanisms have not been elucidated. Our hypothesis is that inflammation due to
infections may increase endothelial cell activation, causing prothrombotic changes
in coagulation, thereby causing more severe strokes.
Methods: People suffering an ischemic stroke in the last 72 hours (n=85) were
recruited. Information on infections was collected from patient notes. ELISAs were
used to measure plasma markers of endothelial cell activation, inflammation and
coagulation.
Results: 32% of people with an acute stroke had an infection in the 7 days post
stroke. There were no differences in characteristics of the groups, except that 77%
of people without an infection took aspirin compared with 46% of people with an
infection (p=0.005). Infection, in particular pneumonia, was related to the subclass
of stroke (OCSP) (p=0.036, with more TACS and fewer LACS in the infection
group). There was a trend for those with an infection to have a larger infarct
volume. Stroke functional outcome was worse in those people with an infection
(p<0.001 for Rankin’s, Barthel and NIHSS scores). Infection was also related
to destination on discharge. People with infections had increased inflammation
(IL-6: p<0.001), increased coagulation (F1+2, p=0.048) and a trend for increased
endothelial activation (vWF, p=0.125). IL-6 was correlated with vWF (R=0.371,
p<0.001) and F1+2 (0.210, p=0.079). 41% of the variation in functional outcome
was explained by linear regression models containing infection + IL-6 + stroke
subtype, or 28% by infection + IL-6 + infarct volume.
Discussion: These data are consistent with our hypothesis that infection increases
inflammation, resulting in a poorer functional outcome. We suggest that IL-6 is
associated with endothelial cell activation and coagulation, and that infection and
IL-6 are independent risk factors for a poor functional outcome
A novel role for CD36 in VLDL-enhanced platelet activation
Full text linkType 2 diabetes is characterized by increased plasma triglyceride levels and a fourfold increase in ischemic heart disease, but the mechanism is unclear. CD36 is a receptor/transporter that binds fatty acids of lipoproteins. CD36 deficiency has been linked with insulin resistance. There is strong evidence of in vivo interaction between platelets and atherogenic lipoproteins suggesting that atherogenic triglyceride-rich lipoproteins, such as VLDL, that are increased in diabetic dyslipidemia are important in this process. This study demonstrates that VLDL binds to the platelet receptor CD36, enhances platelet thromboxane A2 production, and causes increased collagen-mediated platelet aggregation. VLDL enhanced collagen-induced platelet aggregation by 1) shortening the time taken for aggregation to begin (lag time) to 70% of control (P = 0.001); 2) increasing maximum aggregation to 170% of control (P = 0.008); and 3) increasing thromboxane production to 3,318% of control (P = 0.004), where control represents platelets stimulated with collagen (100%). A monoclonal antibody against CD36 attenuated VLDL-enhanced collagen-induced platelet aggregation by 1) inhibiting binding of VLDL to platelets by 75% (P = 0.041); 2) lengthening lag time to 190% (P < 0.001); and 3) decreasing thromboxane production to 8% of control (P < 0.001). In support of this finding, platelets from Cd36-deficient rats showed no increase in aggregation, thromboxane production, and VLDL binding in contrast to platelets from rats expressing CD36. These data suggest that platelet Cd36 has a key role in VLDL-induced collagen-mediated platelet aggregation, possibly contributing to atherothrombosis associated with increased VLDL levels
IL-6 is a predictive biomarker for stroke associated infection and future mortality in the elderly after an ischemic stroke
No full textBackground and purposeStroke associated infection (within the first seven days) occurs in approximately half of stroke patients and is associated with a worse prognosis, especially in the elderly. It is uncertain what factors predict stroke associated infection, yet identification of a suitable biomarker for infection may allow early and appropriate intervention with antibiotics. The aims of this study were to: a) identify independent risk factors for stroke associated infection, and b) test relationships between these risk factors and mortality at 2 years.MethodsEight-two elderly patients were assessed within 72 h of stroke. Data on stroke severity (Barthel Index), stroke associated infection and mortality at 2 years were collected. Inflammatory biomarkers at baseline and 6 months were measured by ELISA. Logistic regression was used to identify risk factors for stroke associated infection and death.ResultsPatients with stroke associated infection, especially pneumonia, had increased IL-6, more severe strokes, and higher mortality. IL-6 was independently associated with stroke associated infection (OR = 19.2, [95%CI 3.68, 100], p < 0.001), after adjustment for other risk factors and cytokines. IL-6 was also independently associated with 2 year mortality (OR = 9.2, [1.0, 85.1], p = 0.031).ConclusionsThese data suggest that IL-6 may be a key biomarker for predicting stroke associated infection and mortality in the first two years post stroke
Aspirin resistance is associated with inflammation, ischemic stroke severity and poorer functional outcome at 6 months
No full textPublished Abstract -
Many people with aphasia retain residual language impairments to varying degrees
of severity following rehabilitation. Currently there is no theory of rehabilitation
that explains the therapeutic process involved in the restoration of a damaged
language system. Therefore it is not possible to discern what approaches/tasks
would be most successful at restoring particular language functions. Does rehabilitation
facilitate the accessing of the damaged language system or could it involve
new learning resulting in the creation of new language representations? The main
objective of this study was to investigate whether adults with aphasia could learn
new vocabulary. The methodology incorporated procedures based on evidence from
the literature in order to facilitate and promote optimum learning. The novel stimuli
(20 new words) were taught to 12 adults (<65 years) who presented with varying
degrees of severity of aphasia. The training procedure incorporated learning theory
and a cognitive neuropsychological model of language. The immediate and delayed
recall of this vocabulary was investigated using a range of assessments to facilitate
the capture of new learning which was measured not only in terms of the accurate
production of the stimuli but also the recognition and knowledge of the word
forms and meanings. Overall findings of this investigation with the presentation
of select case studies demonstrate the ability of people to learn new language
representations despite severe language impairment. The findings, which strongly
suggest that language rehabilitation could incorporate the process of new learning,
have significant clinical relevance in terms of developing a theory of rehabilitation
and to the procedures employed in speech and language therapy.casl23pub2256pubsupp
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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