| 1. |
- Tajeddinn, W., et al.
(författare)
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Association of Platelet Serotonin Levels in Alzheimer's Disease with Clinical and Cerebrospinal Fluid Markers
- 2016
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 53:2, s. 621-630
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Serotonin (5-HT) is involved in the pathology of Alzheimer's disease (AD). Objective: We aimed to measure 5-HT level in platelets in AD and explore its association with cerebrospinal fluid (CSF), AD biomarkers (amyloid-beta 1-42 (A beta(42)), total tau (t-tau), and phosphorylated tau (p-tau)), and clinical symptoms. Methods: 15 patients with AD and 20 patients with subjective cognitive impairment (SCI) were included. 5-HT metabolites were measured, in a specific fraction, using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Results: Significantly lower 5-HT concentrations were observed in AD patients compared to SCI patients both after normalization against total protein (p = 0.008) or platelet count (p = 0.019). SCI patients with lower 5-HT level have higher AD CSF biomarkers, total tau (p = 0.026) and tau/A beta(42) ratio (p = 0.001), compared to those with high 5-HT levels. Conclusion: AD patients have reduced platelet 5-HT levels. In SCI, lower 5-HT content was associated with a higher AD-CSF biomarker burden.
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| 2. |
- Milovanovic, Micha, et al.
(författare)
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Inverse relationship between erythrocyte size and platelet reactivity in elderly.
- 2017
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Ingår i: Platelets. - : Taylor & Francis. - 0953-7104 .- 1369-1635. ; 28:2, s. 182-186
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Tidskriftsartikel (refereegranskat)abstract
- Previous work indicates that erythrocytes (RBCs) accumulate β-amyloid X-40 (Aβ40) in individuals with Alzheimer disease (AD) and to a lesser extent in healthy elderly. The toxin damages RBCs and increases their mean corpuscular volume (MCV). Furthermore, AD platelets demonstrate lower reactivity. This study investigated interactions between RBCs and platelets. Older individuals with moderate hypertension (n = 57) were classified into two groups, depending on MCV in whole blood: The MCV(high) group comprised individuals with higher MCV (n = 27; 97 ± 3(SD) fl) and MCV(low) group had relatively lower MCV (n = 30; 90 ± 3(SD) fl). Flow cytometry was used to determine platelet reactivity, i.e., the surface binding of fibrinogen after provocation. Adenosine diphosphate (ADP) and a thrombin receptor-activating protein (TRAP-6) were used as agonists. Subsequently, blood cells were divided according to density into 17 subfractions. Intra-RBC Aβ40 content was analyzed and in all platelet populations surface-bound fibrinogen was determined to estimate platelet in vivo activity. We found Aβ40 inside RBCs of approximately 50% of participants, but the toxin did not affect MCV and platelet reactivity. In contrast, MCV associated inversely with platelet reactivity as judged from surface-attached fibrinogen after ADP (1.7 μmol/L) (p < 0.05) and TRAP-6 provocation (57 μmol/L (p = 0.01) and 74 μmol/L (p < 0.05)). In several density fractions (nos. 3, 4, 8, 11-13 (p < 0.05) and nos. 5-7 (p < 0.01)) MCV linked inversely with platelet-attached fibrinogen. In our community-dwelling sample, enhanced MCV associated with decreased platelet reactivity and lower in vivo platelet activity. It resembles RBCs and platelet behavior in AD-type dementia.
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| 3. |
- Törnström, T., et al.
(författare)
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Flow and thermal characteristics of warm plane air jets (measurements and predictions using different k-ε models)
- 2001
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Ingår i: Computational Engineering. - 1853128708 ; , s. 33-44
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Konferensbidrag (refereegranskat)abstract
- Jets are often used for supplying air to buildings. For designing ventilation systems it is therefore of great importance to have a good understanding of air jets to avoid draught, which might lead to discomfort. At the same time as we want a good indoor climate, we also want to reduce energy consumption. The purpose of this study is to investigate the flow and thermal characteristics of warm air jets supplied under the ceiling, as a heating method, by means of numerical prediction and full-scale experiments. Together with the warm wall jet, an isothermal wall jet will also be examined. For the calculations, three different k-ε models have been used and evaluated, namely the standard k-ε, the Chen-Kim k-ε model and the Renormalization Group k-ε model. The experiments have been carried out in a full-scale room where the temperature and velocity within the air jet are conducted. For the isothermal wall jet, the Chen model gives best agreement for the growth rate, while the standard k-ε model gives the best result for the velocity decay of the jet. The evaluation of the warm jet provided best results for the Chen model regarding both the growth rate and the velocity decay. The velocity and temperature profiles for the warm jet provided similar results for all models, but also some differences between the predicted and measured temperatures.
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