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Analysis of platelet adhesion to a collagen-coated surface under flow conditions: the involvement of glycoprotein VI in the platelet adhesion 总被引:6,自引:11,他引:6
Platelet adhesion to the exposed surface of the extracellular matrix in flowing blood is the first and critical reaction for in vivo thrombus formation. However, the mechanism of this in vivo platelet adhesion has yet to be studied extensively. One of the reasons for this is the lack of a practical assay method for assessing platelet adhesion under flow conditions. We have devised an assay method (the fluorescent adhesion assay) that is based on the technique originally reported by Hubbell and McIntire (Biomaterials 7:354, 1986) with some modifications to make it more amenable for assaying small samples and have developed an analysis method to quantify the extent of platelet adhesion and aggregation from fluorescence images by using a computer-assisted image analysis system. In our assay, platelet adhesion, expressed as the percentage of the area covered by adhered platelets, was found to increase biphasically as a function of time. In the first phase, platelets interacted with the coated collagen, transiently stopping on the surface; we called this reaction the temporary arrest. In the second phase, platelets adhered much more rapidly and permanently on the surface, and this adhesion was dependent on the shear rate; platelets formed aggregates in this phase. We used our assay to analyze the effects of platelet aggregation inhibitors on platelet adhesion. All three examined inhibitors, EDTA (10 mmol/L), antiglycoprotein (GP) IIb/IIIa, and GRGDS peptide (1 mmol/L), inhibited the second phase adhesion in flowing blood. Furthermore, GPVI-deficient platelets also showed defective second-phase adhesion under the same conditions. These results suggested that GPIIb/IIIa activation and GPVI contribute to the reaction inducing the second phase. The second-phase adhesion has been extensively investigated, and the consensus is that this reaction is mainly attributable to the platelet-platelet interaction. In this report, we were able to detect an earlier reaction, the temporary arrest. This temporary arrest would reflect the fast and weak interaction between platelet GPIb/IX and collagen-von Willebrand factor complexes on the collagen-coated surface. 相似文献
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A A Pontual DP de Melo SM de Almeida FN Bóscolo F Haiter Neto 《Dento maxillo facial radiology》2010,39(7):431-436
Objectives
The aims of this study were (1) to compare the accuracy of the detection of approximal enamel caries lesions using three intraoral storage phosphor plate digital systems and one conventional film-based radiographic system; and (2) to determine whether there is a correlation between the histological and radiographic measurements of enamel caries.Methods
160 approximal surfaces were radiographed under standardized conditions using three storage phosphor stimulable systems (DenOptix and Digora FMX with white and blue plates), and one film system (Insight film). 17 observers scored the images for the presence and depth of caries using a 4-point scale. The presence of caries was validated histologically (gold standard). Two-way analysis of variance was used to test the differences in sensitivity, specificity and overall accuracy (TP + TN). The data from the radiographic and histological measurements were statistically analysed by Spearman’s rank correlation coefficient.Results
Two-way analysis of variance and the post hoc t-test demonstrated that Digora (white plate) had higher specificity and overall accuracy values than DenOptix (P = 0.021); there was no statistically significant difference among the other imaging modalities (P > 0.05). There was no significant correlation between the histological depth measurements and the radiographic measurements from Digora (blue plate) (P = 0.43), Digora (white plate) (P = 0.15), DenOptix (P = 0.17) and Insight film (P = 0.06).Conclusions
The results suggest that (1) the performance of the three storage phosphor image plate systems was similar to that of the Insight film for detection of approximal enamel caries, and (2) the increase in histological depth of enamel caries was not significantly correlated with radiographic measurements. 相似文献146.
Jessica C Fanzo Matthew M Graziose Klaus Kraemer Stuart Gillespie Jessica L Johnston Saskia de Pee Eva Monterrosa Jane Badham Martin W Bloem Alan D Dangour Richard Deckelbaum Achim Dobermann Patrizia Fracassi SM Moazzem Hossain John Ingram Johann C Jerling CJ Jones Stefanus Indrayana Jap Lynnda Kiess Quinn Marshall Keith Martin Anuradha Narayan Mary Amuyunzu-Nayamongo Fré Pepping Keith P West 《Advances in nutrition (Bethesda, Md.)》2015,6(6):639-647
Nearly all countries in the world today are burdened with malnutrition, manifesting as undernutrition, micronutrient deficiencies, and/or overweight and obesity. Despite some progress, efforts to alleviate malnutrition are hampered by a shortage in number, skills, and geographic coverage, of a workforce for nutrition. Here, we report the findings of the Castel Gandolfo workshop, a convening of experts from diverse fields in March 2014 to consider how to develop the capacity of a global cadre of nutrition professionals for the post-2015 development era. Workshop participants identified several requirements for developing a workforce for nutrition, including an ability to work as part of a multisectoral team; communication, advocacy, and leadership skills to engage decision makers; and a set of technical skills to address future challenges for nutrition. Other opportunities were highlighted that could immediately contribute to capacity development, including the creation of a consortium to link global North and South universities, online training modules for middle managers, and practical, hands-on experiences for frontline nutrition workers. Institutional and organizational support is needed to enable workshop recommendations on education and training to be effectively implemented and sustained. The findings from the Castel Gandolfo workshop can contribute to the delivery of successful nutrition-relevant actions in the face of mounting external pressures and informing and attaining the forthcoming Sustainable Development Goals. 相似文献
147.
Evan L. Thacker SM Honglei Chen MD PhD Alpa V. Patel PhD Marjorie L. McCullough ScD Eugenia E. Calle PhD Michael J. Thun MD Michael A. Schwarzschild MD PhD Alberto Ascherio MD DrPH 《Movement disorders》2008,23(1):69-74
The purpose of this study was to investigate associations between recreational physical activity and Parkinson's disease (PD) risk. We prospectively followed 143,325 participants in the Cancer Prevention Study II Nutrition Cohort from 1992 to 2001 (mean age at baseline = 63). Recreational physical activity was estimated at baseline from the reported number of hours per week on average spent performing light intensity activities (walking, dancing) and moderate to vigorous intensity activities (jogging/running, lap swimming, tennis/racquetball, bicycling/stationary bike, aerobics/calisthenics). Incident cases of PD (n = 413) were confirmed by treating physicians and medical record review. Relative risks (RR) were estimated using proportional hazards models, adjusting for age, gender, smoking, and other risk factors. Risk of PD declined in the highest categories of baseline recreational activity. The RR comparing the highest category of total recreational activity (men ≥ 23 metabolic equivalent task‐hours/week [MET‐h/wk], women ≥ 18.5 MET‐h/wk) to no activity was 0.8 (95% CI: 0.6, 1.2; P trend = 0.07). When light activity and moderate to vigorous activity were examined separately, only the latter was found to be associated with PD risk. The RR comparing the highest category of moderate to vigorous activity (men ≥ 16 MET‐h/wk, women ≥ 11.5 MET‐h/wk) to the lowest (0 MET‐h/wk) was 0.6 (95% CI: 0.4, 1.0; P trend = 0.02). These results did not differ significantly by gender. The results were similar when we excluded cases with symptom onset in the first 4 years of follow‐up. Our results may be explained either by a reduction in PD risk through moderate to vigorous activity, or by decreased baseline recreational activity due to preclinical PD. © 2007 Movement Disorder Society 相似文献
148.
Simone SM Ho Winnie WM Yu Terence T Lao Daniel HK Chow Joanne WY Chung Yi Li 《Journal of clinical nursing》2009,18(11):1523-1532
Aims. This article aims to review the literature published to date on the types, current use, the biomechanical effects and adverse effects of maternity support belts for low back pain during pregnancy, to identify future research directions. Background. Lumbar/pelvic support belts are frequently recommended for the prevention and treatment of low back pain during pregnancy. Design. Systematic review. Methods. MEDLINE, CINAHL, the Cochrane Library and patents databases were electronically searched. Results. Maternity support belts belong to one of the four main types of maternity support garments, which are widely commercially‐available. Current research showed limited evidence in support of the commercial maternity products regarding the effectiveness in the prevention and/or treatment of low back pain during pregnancy, other than that from the manufacturers. However, potential stabilisation effect of maternity support belt was demonstrated in some studies. Adverse effects reported include increased pain, fetal heart rate changes, skin irritation and discomfort. Conclusions. There is insufficient scientific evidence to conclude that wearing maternity support belts reduces pregnancy‐related low back pain and/or pelvic girdle pain. Future research directions in the area of biomechanics and physiology are recommended. Relevance to clinical practice. This review provides comprehensive understanding of the effectiveness of maternity support belts for the relief of low back pain during pregnancy which will facilitate healthcare professionals in providing evidence‐based advice to their patients. 相似文献
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