Four Component Passerini Polymerization of Bulky Monomers under High Shear Flow

2021 ◽  
Author(s):  
Bryan T. Tuten ◽  
Aaron H Bui ◽  
Sandra Wiedbrauk ◽  
Vinh Truong ◽  
Colin L Raston ◽  
...  
Keyword(s):  
Shear Flow ◽  
High Shear ◽  
Passerini Reaction

We introduce a four component Passerini polymerization utilizing sterically bulky isocyanide monomers. Under typical Passerini conditions, bulky isocyanides do not react within standard Passerini reaction timescales (hours). We overcome this...

scholarly journals Distinct dietary alpha-linolenic acid-dependent shifts in the fecal microbiome composition suppresses aging-associated inflammatory responses and thrombus formation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S.S Saeedi Saravi ◽  
N.R Bonetti ◽  
G.G Camici ◽  
T.F Luscher ◽  
J.H Beer
Keyword(s):  
Platelet Aggregation ◽  
Shear Flow ◽  
Plasma Levels ◽  
Inflammatory Responses ◽  
Thrombus Formation ◽  
Funding Source ◽  
High Shear ◽  
Fecal Microbiome ◽  
Microbiome Composition

Abstract Background Aging is associated with alterations in the fecal microbiome composition. The microbiota-derived trimethylamine-N-oxide (TMAO) correlates with arterial thrombotic events, e.g. myocardial infarction and stroke, the leading causes of mortality worldwide. The omega-3 fatty acid (n-3 FA) α-linolenic acid (ALA) has been shown to be protective against thrombosis and associated pathologies. Therefore, we hypothesized that long-term dietary ALA supplementation protects against the aging-associated microbiome dysbiosis, and reduces inflammatory and thrombotic responses. Methods 24 week-old male C57BL/6 mice were fed either a high ALA (7.3g%) or low ALA (0.03g%) diet for 12 months. We examined the compositional changes of fecal microbiota of the animals treated with high vs. low ALA via 16S rRNA gene sequencing. The plasma levels of TMAO and its precursors choline and betaine, and LPS were measured by ELISA. Additionally, the platelet aggregation in response to thrombin, and thrombus formation on collagen under high-shear flow conditions of 3000/sec (to mimic blood flow in stenosed arteries) were investigated. Results Genomic analyses showed that the abundance of Phylum Proteobacteria and the family of desulfovibrio were reduced 71.72% and 51.73% in the aged high ALA-treated mice (p<0.01 and p<0.001, resp.) that may result in decrease in TAMO production and the subsequent inflammatory responses. However, microbial diversity of Bacteroidetes or Fermicutes and Bacteroidetes/Fermicutes ratio did not demonstrate a significant change between high vs. low ALA groups. Interestingly, the dietary intake of high ALA increased the abundance of Lachnospiraceae (p<0.01) that may exert anti-inflammatory effects. Importantly, high ALA significantly decreased the plasma levels of TMAO (p<0.01) and its precursor choline (P<0.05), but not betaine. The pro-inflammatory cytokine TNF-α showed a significant reduction (p<0.05), whereas plasma IL-1β did not change significantly following high ALA supplementation. An increased thrombus formation on collagen under high-shear flow (36.34%, p<0.01) and thrombin-induced platelet aggregation (31.31%, p<0.05) were found in the aged mice. Conclusion These studies demonstrate that an ALA-rich diet induces beneficial bacterial shifts in the aging-associated fecal microbiome that may lead to the suppression of inflammatory and thrombotic responses. Hence, long-term dietary ALA supplementation may be exploited as a nutritional antithrombotic strategy in the aging. Microbiome-Thrombosis-Aging Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Swiss National Science Foundation (SNSF)

scholarly journals Platelet Shape Changes and Adhesion Under High Shear Flow

2002 ◽  
Vol 22 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Mitsuhiro Kuwahara ◽  
Mitsuhiko Sugimoto ◽  
Shizuko Tsuji ◽  
Hideto Matsui ◽  
Tomohiro Mizuno ◽  
...  
Keyword(s):  
Shear Flow ◽  
High Shear ◽  
Shape Changes ◽  
Platelet Shape

scholarly journals CRT-403 Incomplete Stent Apposition Causes High Shear Flow Disturbances And Delay In Neointimal Coverage

2015 ◽  
Vol 8 (2) ◽  
pp. S37
Author(s):  
Nicolas Foin ◽  
Juan Luis Gutiérrez-Chico ◽  
Shimpei Nakatani ◽  
Ryo Torii ◽  
Renick Lee ◽  
...  
Keyword(s):  
Shear Flow ◽  
High Shear ◽  
Incomplete Stent Apposition ◽  
Flow Disturbances ◽  
Neointimal Coverage

Role of Von Willebrand Factor Triplet Bands in Glycoprotein Ib-Dependent Platelet Adhesion Under Flow Conditions

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3356-3356
Author(s):  
Bruce A. Schwartz ◽  
Christoph Kannicht ◽  
Birte Fuchs ◽  
Mario Kröning ◽  
Barbera Solecka
Keyword(s):  
Shear Flow ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Peptide Sequence ◽  
High Shear ◽  
Collagen Type Iii ◽  
Flow Conditions ◽  
Triplet Structure ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 3356 Objective: Multimeric glycoprotein von Willebrand factor (VWF) exhibits a unique triplet structure of individual oligomers, resulting from ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs 13) cleavage. The faster and slower migrating triplet bands of a given VWF multimer respectively have one shorter or longer N-terminal peptide sequence. Within this peptide sequence, the A1 domain regulates interaction of VWF with platelet glycoprotein (GP)Ib. Distribution of VWF triplet bands is significantly altered in some types of VWD, however, the impact of triplet structure on VWF function has not been investigated so far. Methods: Platelet-adhesive properties of two VWF preparations with similar multimeric distribution but different triplet composition obtained by size exclusion in addition to heparin affinity chromatography were investigated for differential functional activities. Preparation A was enriched in intermediate triplet bands, while preparation B predominantly contained larger triplet bands. Collagen- and GPIb-binding was determined by surface plasmon resonance (SPR). Platelet adhesion under flow was determined using flow-chamber models. Results: Binding studies revealed that preparation A displayed a reduced affinity for recombinant GPIb, but an unchanged affinity for collagen type III, when compared to preparation B. Under high-shear flow conditions, preparation A was less active in recruiting platelets to collagen type III. Furthermore, when added to blood from patients with von Willebrand disease (VWD), defective thrombus formation was less restored. Conclusion: Thus, VWF forms lacking larger size triplet bands appear to have a decreased potential to recruit platelets to collagen-bound VWF under arterial flow conditions. By implication, changes in triplet band distribution observed in patients with VWD may result in altered platelet adhesion at high-shear flow. Disclosures: Schwartz: Octapharma: Employment. Kannicht:Octapharma: Employment. Fuchs:octapharma: Employment. Kröning:octapharma: Employment. Solecka:Octapharma: Employment.

Rupture of Phospholipid Bilayer under High Shear Flow:

2018 ◽  
Vol 2018 (0) ◽  
pp. J0250002
Author(s):  
Taiki SHIGEMATSU ◽  
Kenichiro KOSHIYAMA ◽  
Shigeo WADA
Keyword(s):  
Shear Flow ◽  
Phospholipid Bilayer ◽  
High Shear

scholarly journals Integrin VLA-4 enhances sialyl-Lewisx/a-negative melanoma adhesion to and extravasation through the endothelium under low flow conditions

2008 ◽  
Vol 295 (3) ◽  
pp. C701-C707 ◽  
Author(s):  
Shile Liang ◽  
Cheng Dong
Keyword(s):  
Endothelial Cells ◽  
Shear Flow ◽  
Tumor Cells ◽  
Melanoma Cell ◽  
Melanoma Cells ◽  
Host Cells ◽  
High Shear ◽  
Sialyl Lewis ◽  
Adhesive Interactions ◽  
Low Shear

During their passage through the circulatory system, tumor cells undergo extensive interactions with various host cells including endothelial cells. The capacity of tumor cells to form metastasis is related to their ability to interact with and extravasate through endothelial cell layers, which involves multiple adhesive interactions between tumor cells and endothelium (EC). Thus it is essential to identify the adhesive receptors on the endothelial and melanoma surface that mediate those specific adhesive interactions. P-selectin and E-selectin have been reported as adhesion molecules that mediate the cell-cell interaction of endothelial cells and melanoma cells. However, not all melanoma cells express ligands for selectins. In this study, we elucidated the molecular constituents involved in the endothelial adhesion and extravasation of sialyl-Lewisx/a-negative melanoma cell lines under flow in the presence and absence of polymorphonuclear neutrophils (PMNs). Results show the interactions of α4β1(VLA-4) on sialyl-Lewisx/a-negative melanoma cells and vascular adhesion molecule (VCAM-1) on inflamed EC supported melanoma adhesion to and subsequent extravasation through the EC in low shear flow. These findings provide clear evidence for a direct role of the VLA-4/VCAM-1 pathway in melanoma cell adhesion to and extravasation through the vascular endothelium in a shear flow. PMNs facilitated melanoma cell extravasation under both low and high shear conditions via the involvement of distinct molecular mechanisms. In the low shear regime, β2-integrins were sufficient to enhance melanoma cell extravasation, whereas in the high shear regime, selectin ligands and β2-integrins on PMNs were necessary for facilitating the melanoma extravasation process.

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