The role of plasma in the yield stress of blood.

Background: Yielding and shear elasticity of blood are merely discussed within the context of hematocrit and erythrocyte aggregation. However, plasma might play a substantial role due its own viscoelasticity.

Objective: If only erythrocyte aggregation and hematocrit would determine yielding, blood of different species with comparable values would present comparable yield stresses.

Cow blood - A superior storage option in forensics?

Given the use of modified blood products (e.g. leucocyte depleted erythrocyte concentrates in SAG-mannitol, dehydrated blood powder, defibrinated blood), drawing blood from conscious animals while minimizing their stress is a good option to obtain blood for bloodstain pattern analysis.

Systematic Comparison of Commercial Hydrogels Revealed That a Synergy of Laminin and Strain-Stiffening Promotes Directed Migration of Neural Cells.

Hydrogels have shown potential in replacing damaged nerve tissue, but the ideal hydrogel is yet to be found. In this study, various commercially available hydrogels were compared. Schwann cells, fibroblasts, and dorsal root ganglia neurons were seeded on the hydrogels, and their morphology, viability, proliferation, and migration were examined.

Chorion-derived extracellular matrix hydrogel and fibronectin surface coatings show similar beneficial effects on endothelialization of expanded polytetrafluorethylene vascular grafts.

The endothelium plays an important regulatory role for cardiovascular homeostasis. Rapid endothelialization of small diameter vascular grafts (SDVGs) is crucial to ensure long-term patency. Here, we assessed a human placental chorionic extracellular matrix hydrogel (hpcECM-gel) as coating material and compared it to human fibronectin in-vitro.

A Bayesian approach to blood rheological uncertainties in aortic hemodynamics.

Computational hemodynamics has received increasing attention recently. Patient-specific simulations require questionable model assumptions, for example, for geometry, boundary conditions, and material parameters. Consequently, the credibility of these simulations is much doubted, and rightly so.

Capillary-size flow of human blood plasma: Revealing hidden elasticity and scale dependence.

The dynamical mechanical analysis of blood generally uses models inspired by conventional flows, assuming scale-independent homogeneous flows and without considering fluid-surface boundary interactions. The present experimental study highlights the relevance of using an approach in line with physiological reality providing a strong interaction between the fluid and the boundary interface. New dynamic properties of human blood plasma are found: a finite shear elastic response (solid-like property) is identified in nearly static conditions, which also depends on the scale (being reinforced at small scales).

Red Blood Cell Stiffness and Adhesion Are Species-Specific Properties Strongly Affected by Temperature and Medium Changes in Single Cell Force Spectroscopy.

Besides human red blood cells (RBC), a standard model used in AFM-single cell force spectroscopy (SCFS), little is known about apparent Young's modulus (Ea) or adhesion of animal RBCs displaying distinct cellular features. To close this knowledge gap, we probed chicken, horse, camel, and human fetal RBCs and compared data with human adults serving as a repository for future studies. Additionally, we assessed how measurements are affected under physiological conditions (species-specific temperature in autologous plasma vs.

Animal blood in translational research: How to adjust animal blood viscosity to the human standard.

Animal blood is used in mock circulations or in forensic bloodstain pattern analysis. Blood viscosity is important in these settings as it determines the driving pressure through biomedical devices and the shape of the bloodstain. However, animal blood can never exactly mimic human blood due to erythrocyte properties differing among species.

Blood Clot Phenotyping by Rheometry: Platelets and Fibrinogen Chemistry Affect Stress-Softening and -Stiffening at Large Oscillation Amplitude.

(1) Background: Together with treatment protocols, viscoelastic tests are widely used for patient care. Measuring at broader ranges of deformation than currently done will add information on a clot's mechanical phenotype because fibrin networks follow different stretching regimes, and blood flow compels clots into a dynamic non-linear response. (2) Methods: To characterize the influence of platelets on the network level, a stress amplitude sweep test (LAOStress) was applied to clots from native plasma with five platelet concentrations.

Gingipain R1 and Lipopolysaccharide From Have Major Effects on Blood Clot Morphology and Mechanics.

and its inflammagens are associated with a number of systemic diseases, such as cardiovascular disease and type 2 diabetes (T2DM). The proteases, gingipains, have also recently been identified in the brains of Alzheimer's disease patients and in the blood of Parkinson's disease patients. Bacterial inflammagens, including lipopolysaccharides (LPSs) and various proteases in circulation, may drive systemic inflammation.

The effect of hematocrit, fibrinogen concentration and temperature on the kinetics of clot formation of whole blood.

Background: Dynamic mechanical analysis of blood clots can be used to detect the coagulability of blood.

Objective: We investigated the kinetics of clot formation by changing several blood components, and we looked into the clot "signature" at its equilibrium state by using viscoelastic and dielectric protocols.

Methods: Oscillating shear rheometry, ROTEM, and a dielectro-rheological device was used.

Storability of porcine blood in forensics: How far should we go?

Previous studies on the storability of porcine blood for bloodstain pattern analysis (BPA) focused on abattoir blood only and did not include measurements of viscoelasticity. Although known to provoke echinocyte formation, EDTA is widely used for BPA issues. We compared ageing samples taken from live pigs with abattoir blood and detected considerable differences in hematocrit (HCT), total protein and shear viscosity that even worsened with time.

Near-Newtonian Blood Behavior - Is It Good to Be a Camel?

From a certain level of exercise-intensity onward, hematocrit increases in horses, which brings more oxygen carriers into the bloodstream. Camels, however, when used in competitive racing could be even in need of iron supplementation and blood transfusions due to a severe reduction of their available hematocrit compared to their resting hematocrit. Since the extrinsic and intrinsic mechanical properties of camel erythrocytes (RBC) are so different compared to RBCs of other mammals, the question arises whether this observation might be a response to endurance exercise aiming at keeping the RBC count low.

Altered membrane rigidity via enhanced endogenous cholesterol synthesis drives cancer cell resistance to destruxins.

Destruxins, secondary metabolites of entomopathogenic fungi, exert a wide variety of interesting characteristics ranging from antiviral to anticancer effects. Although their mode of action was evaluated previously, the molecular mechanisms of resistance development are unknown. Hence, we have established destruxin-resistant sublines of HCT116 colon carcinoma cells by selection with the most prevalent derivatives, destruxin (dtx)A, dtxB and dtxE.

Temperature dependency of whole blood viscosity and red cell properties in desert ungulates: Studies on scimitar-horned oryx and dromedary camel.

Background: The dromedary camel and the oryx antelope are exposed to excessive heat and solar radiation in their desert habitat. Desertification of areas with by now little rainfall may occur eventually. Well-adapted large animal species show us what is needed to survive in scorching regions.

Viscoelasticity and structure of blood clots generated in-vitro by rheometry: A comparison between human, horse, rat, and camel.

Background: Although the coagulation system is evolutionary well preserved, profound species differences exist in viscoelastic as well as in common laboratory tests of coagulation.

Objective: Evaluating differences in clot formation and material characterisation of clots of four mammalian species on macro-, micro- and nanoscales by the means of rheometry, scanning electron microscopy (SEM) and small angle x-ray scattering (SAXS).

Methods: Blood samples were collected from healthy human volunteers, laboratory rats (HL/LE inbred strain), warmblood horses and dromedary camels.

Very large and giant microsurgical bifurcation aneurysms in rabbits: Proof of feasibility and comparability using computational fluid dynamics and biomechanical testing.

Background: Giant aneurysms are challenging lesions with unacceptable high rates of aneurysm recanalization and rerupture following embolization. Reliable in vivo models are urgently needed to test the performance of new more efficient endovascular devices.

Materials And Methods: Aneurysms were created in 11 New Zealand white rabbits (4.

Evaluation of canine red blood cell quality after processing with an automated cell salvage device.

Objective: To evaluate the properties of RBC concentrate harvested after processing fresh whole blood units from healthy dogs with an automated cell salvage device.

Design: Prospective, in vitro, experimental study.

Setting: University teaching hospital.

Hemorheology in experimental research: is it necessary to consider blood fluidity differences in the laboratory rat?

This study was designed to identify whether blood fluidity differs between commercially available laboratory rat strains. The hemorheological profiles of seven clinically healthy wild-type rat strains were analyzed to determine whether any diversity in blood fluidity might affect the outcome of cardiovascular studies. Study 1: 65 healthy adult rats (Lewis, Long-Evans, Hairless, Wistar and Fisher; mixed gender and comparable ages) were compared.

Anticancer activity of methyl-substituted oxaliplatin analogs.

Oxaliplatin is successfully used in systemic cancer therapy. However, resistance development and severe adverse effects are limiting factors for curative cancer treatment with oxaliplatin. The purpose of this study was to comparatively investigate in vitro and in vivo anticancer properties as well as the adverse effects of two methyl-substituted enantiomerically pure oxaliplatin analogs [[(1R,2R,4R)-4-methyl-1,2-cyclohexanediamine] oxalatoplatinum(II) (KP1537), and [(1R,2R,4S)-4-methyl-1,2-cyclohexanediamine]oxalatoplatinum(II) (KP1691)] and to evaluate the impact of stereoisomerism.

Comparative ultrastructure of fibrin networks of a dog after thrombotic ischaemic stroke.

A cerebrovascular accident or stroke is a rare condition in dogs, but previous studies suggest that it is now increasingly being recognised. Platelets and fibrin networks are involved in haemostasis,which is disrupted during a thrombotic event. In this study we investigate the ultrastructure of the fibrin networks of a dog that had suffered ischaemic stroke, following suspected thromboembolism from clots that became dislodged during catheter maintenance (flushing with heparinised saline) 2 days after carotid artery catheter insertion.

Influence of fatty acid composition in mammalian erythrocytes on cellular aggregation.

The rheologic properties of red blood cells (RBC) are determined by humoral and cellular factors. Fatty acid composition of the RBC phospholipid bilayer is one factor influencing membrane fluidity this could affect RBC aggregation because of a higher bias of RBC deformability. The present investigation was performed to investigate a possible relationship between fatty acid composition and erythrocyte aggregation using animals with high RBC aggregation (horse and pig) and animals with immeasurable RBC aggregation (sheep).

The fluidity of blood in African elephants (Loxodonta africana).

The large cellular volume of erythrocytes and the increased plasma concentration of proteins in elephants are factors which potentially affect blood rheology adversely. To verify blood rheology, routine hemorheologic variables were analyzed in four African elephants (Loxodonta africana), housed in the zoo of Vienna. Whole blood viscosity at three different shear rates (WBV at low shear rate: WBV 0.