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Jeffrey J. Perry Mukul Sharma Marco L.A. Sivilotti Jane Sutherland Cheryl Symington Andrew Worster Marcel ��mond Grant Stotts Albert Y. Jin Weislaw J. Oczkowski Demetrios J. Sahlas Heather E. Murray Ariane MacKey Steve Verreault George A. Wells Ian G. Stiell 《CMAJ》2011,183(10):1137-1145
Background:
The ABCD2 score (Age, Blood pressure, Clinical features, Duration of symptoms and Diabetes) is used to identify patients having a transient ischemic attack who are at high risk for imminent stroke. However, despite its widespread implementation, the ABCD2 score has not yet been prospectively validated. We assessed the accuracy of the ABCD2 score for predicting stroke at 7 (primary outcome) and 90 days.Methods:
This prospective cohort study enrolled adults from eight Canadian emergency departments who had received a diagnosis of transient ischemic attack. Physicians completed data forms with the ABCD2 score before disposition. The outcome criterion, stroke, was established by a treating neurologist or by an Adjudication Committee. We calculated the sensitivity and specificity for predicting stroke 7 and 90 days after visiting the emergency department using the original “high-risk” cutpoint of an ABCD2 score of more than 5, and the American Heart Association recommendation of a score of more than 2.Results:
We enrolled 2056 patients (mean age 68.0 yr, 1046 (50.9%) women) who had a rate of stroke of 1.8% at 7 days and 3.2% at 90 days. An ABCD2 score of more than 5 had a sensitivity of 31.6% (95% confidence interval [CI] 19.1–47.5) for stroke at 7 days and 29.2% (95% CI 19.6–41.2) for stroke at 90 days. An ABCD2 score of more than 2 resulted in sensitivity of 94.7% (95% CI 82.7–98.5) for stroke at 7 days with a specificity of 12.5% (95% CI 11.2–14.1). The accuracy of the ABCD2 score as calculated by either the enrolling physician (area under the curve 0.56; 95% CI 0.47–0.65) or the coordinating centre (area under the curve 0.65; 95% CI 0.57–0.73) was poor.Interpretation:
This multicentre prospective study involving patients in emergency departments with transient ischemic attack found the ABCD2 score to be inaccurate, at any cut-point, as a predictor of imminent stroke. Furthermore, the ABCD2 score of more than 2 that is recommended by the American Heart Association is nonspecific.There are approximately 100 visits to the emergency department per 100 000 population for transient ischemic attack each year.1 Although often considered benign, transient ischemic attack carries a risk of imminent stroke. Studies have shown that the risk of stroke is 0.2%–10% within 7 days of the first transient ischemic attack, and this risk increases to 1.2%–12% at 90 days.2–9 Stroke continues to be the leading cause of disability among adults and the third-leading cause of death in North America.10,11 Identifying people with transient ischemic attack who are at high risk of stroke is an opportunity to prevent stroke.3,4 However, urgent investigation of all transient ischemic attacks would require substantial resources. Three studies have attempted to develop clinical decision rules (i.e., scores) for assessing whether a patient with transient ischemic attack is at high risk of stroke.9,12,13 Combined, these studies led to the development of the ABCD2 (Age, Blood pressure, Clinical features, Duration of symptoms and Diabetes) score. However, despite its widespread implementation, the ABCD2 score has not yet been prospectively validated.12,14–18 This essential step in the development of rules for making clinical predictions has recently been requested.14,19–21The objective of this study was to externally validate the ABCD2 score as a tool for identifying patients seen in the emergency department with transient ischemic attack who are at high risk of stroke within 7 (primary outcome) and 90 days (one of the secondary outcomes). 相似文献123.
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Many different cultivation techniques and inoculum products of the plant-beneficial arbuscular mycorrhizal (AM) fungi have
been developed in the last decades. Soil- and substrate-based production techniques as well as substrate-free culture techniques
(hydroponics and aeroponics) and in vitro cultivation methods have all been attempted for the large-scale production of AM
fungi. In this review, we describe the principal in vivo and in vitro production methods that have been developed so far.
We present the parameters that are critical for optimal production, discuss the advantages and disadvantages of the methods,
and highlight their most probable sectors of application. 相似文献
127.
Fenpropimorph and fenhexamid impact phosphorus translocation by arbuscular mycorrhizal fungi 总被引:1,自引:0,他引:1
Fenpropimorph and fenhexamid are sterol biosynthesis inhibitor (SBI) molecules widely used to control diseases in agriculture.
Both molecules, at increasing concentrations, have been shown to impact on the non-target arbuscular mycorrhizal (AM) fungi.
Root colonization, spore production and mycelium architecture, including the branched absorbing structures which are thought
to be involved in phosphorus (P) uptake, were affected. In the present study, we investigated the capacity of Glomus sp. MUCL 43204 to take up, transfer and translocate labelled P to Medicago truncatula in the presence of these SBI molecules. We used a strict in vitro cultivation system associating an autotrophic plant of
M. truncatula with the AM fungus. In addition, the effects of both SBI molecules on the proportion of hyphae with alkaline phosphatases
(ALP), succinate dehydrogenase (SDH) activity and on the expression of the mycorrhiza-specific plant phosphate transporter
MtPT4 gene were examined. We demonstrated that the two SBI molecules impacted the AM fungus. This was particularly evidenced
for fenpropimorph. A decrease in P transport and ALP and SDH activities associated with the extraradical mycelium and MtPT4 expression level was noted. These three factors were closely related to the development of the AM fungus, suggesting a direct
impact not only on the AM fungal growth but also on the physiology and metabolic activities of the AM fungus. These results
further emphasized the interest on the autotrophic in vitro culture system as an alternative to pot experiments to investigate
the mechanisms behind the impact of disease control molecules on the non-target AM fungal symbionts. 相似文献
128.
C��cile Brun 《Vegetation History and Archaeobotany》2011,20(2):135-142
The focus of palaeoenvironmental sciences on past human activities and their impact on the environment necessitates a precise
understanding of the history and functioning of past and present anthropogenic ecosystems. A process is outlined which uses
palaeoenvironmental and historical documentation as well as present-day observations of vegetational changes from two different
plant communities, which are characterised by a very specific anthropogenic flora: arable weeds and ruderals. This study is
coupled with modern pollen deposition data to deduce a set of pollen types characteristic of the range of human activities
practised in eastern France, a region rich in pollen data. First, phytogeographical analysis of the evolution of these plant
communities since the Neolithic enables the comparison to be validated. By distinguishing between native plants and aliens
introduced long ago (archaeophytes), or more recently (neophytes), and by refining their ecological characteristics, the method
also enables identification of species that are strong indicators of human activities. Next, local pollen deposition in these
vegetation types is examined with a number of statistical analyses (PCIA, Davis indices), confirming the relationships between
a given vegetation community, its theoretical pollen rain and its actual pollen rain, thus distinguishing local and regional
pollen indicators. Lastly, comparison of the results obtained by these two approaches leads to a critical synthesis of the
traditional anthropogenic pollen indicators (Behre’s “indicator species”) in the study area and to the establishment of more
specific local pollen indicators. 相似文献
129.
Charl��ne Bouchaud Margareta Tengberg Patricia Dal Pr�� 《Vegetation History and Archaeobotany》2011,20(5):405-417
The discovery of seeds and textiles from Gossypium (cotton) in Achaemenian levels of the mid-6th–late 4th century b.c. at Qal’at al-Bahrain, Bahrain and in early 1st millennium a.d. at Mada’in Salih, Saudi Arabia, reveals the role played by the Arabian Peninsula as a textile production centre during the
centuries before and after the beginning of the Christian era. Both these sites were situated on important trade routes, overseas
(Qal’at al-Bahrain) and overland (Mada’in Salih), and it is likely that at least part of the cotton production was intended
for trade, complementing and perhaps competing with other sources of cotton textiles in the contemporary Middle East. In the
arid climate of the Arabian Peninsula, cotton was probably grown in association with irrigated date palm gardens where a wide
array of other crops was grown, as is shown by the analysis of charred seeds and wood from occupation levels at both sites.
The present article places these particular finds in the larger context of cotton cultivation in the Middle East and India. 相似文献
130.