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Nanosensor Laboratory
Published in Vinod Kumar Khanna, Nanosensors, 2021
Do CNTs exhibit toxicity? Yes. In the context of toxicology, the nanometer-scale dimensions of CNTs result in milligram quantities possessing a large number of cylindrical, fiber-like particles with a very high total surface area. Batches of pristine CNT (nonpurified and/or nonfunctionalized), after synthesis, contain impurities such as amorphous carbon and metallic nanoparticles (catalysts: Co, Fe, Ni, or Mo), which are the sources of severe toxic effects. Platelet aggregation in blood is induced by both SWCNTs and MWCNTs but not by the C60 fullerenes that are used as the building blocks for these CNTs. Platelets are the small, colorless, disc-shaped fragments, with no nucleus, found in blood and involved in its clotting.
The Human Immune System Seen from a Biomedical Engineering Viewpoint
Published in Robert B. Northrop, Endogenous and Exogenous Regulation and Control of Physiological Systems, 2020
Plateletshave two major functions in the body. One is to form clots to stop bleeding from wounds. Clot formation is a very complex biochemical process which will not be detailed here. The other function is to participate in inflammatory reactions of the immune system. There is normally from 1.5 × 105 to 4 × 105 platelets per cubic millimeter of blood. Platelets are made in the bone marrow by megakaryocytes and then enter the blood. Like red blood cells, they are cells without nuclei, ranging from 2 to 4 um in diameter. Their resting shape is discoidal; however, when activated by appropriate stimuli, they become spheroidal and develop many protruding “tentacle-like” protrusions up to 5 (um in length. They have typical phospholipid bilayer plasma membranes with many embedded receptor molecules. Their cytoplasm contains a “skeleton” of microtubules, largely formed from actin and myosin, proteins normally associated with muscles. Also within platelets are mitochondria, several types of secretory storage granules, and an endoplasmic reticulum. The half-life of platelets is from 8 to 12 days. Most are destroyed by macrophages residing in the spleen.59
Drug Discovery in Microbial Metabolites: The Search for Microbial Products with Bioactive Properties
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
Some megakaryocytes give rise to red blood cells while others fragment to give platelets. Blood contains 150,000 to 350,000 platelets per ml. They are important in blood clotting. When the wall of a blood vessel is damaged by disease or by a trauma such as a cut, thrombin is formed and this acts on the soluble fibrinogen present in the blood to form insoluble fibrin strands. The fibrin strands trap platelets to form blood blots. Blot clots forming within the blood vessels are dangerous and, if large enough, could block blood vessels leading to the heart causing a heart attack or in blood vessels leading to the brain, a stroke. Platelet aggregation inhibitors are useful in preventing cardiovascular disorders through preventing clots. Platelet aggregation inhibition is measured against a control by a turbidometric assay of the platelets to which the metabolite and thrombin are mixed.
Toxicity in vitro reveals potential impacts of microplastics and nanoplastics on human health: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Qingying Shi, Jingchun Tang, Rutao Liu, Lan Wang
Platelets, the smallest of the human blood cells, are central players in processes of hemostasis, inflammation, wound healing, and host defense. Exposure of platelets to engineered nanoparticles has been demonstrated to induce platelet aggregation in vitro (Radomski et al., 2005). Smyth et al. (2015) indicated that most tested PS NPs resulted in GPIIb/IIIa-mediated platelet aggregation and their potencies varied with surface chemistry and size, where, as for the tested 50 nm PS NPs (15–60 μg/mL), carboxylated PS NPs were the most potent, and unmodified PS NPs were the least. By contrast, comparison of 100 nm PS NPs (8–60 μg/mL) showed that unmodified PS NPs were the most potent whereas carbonylated PS NPs were the least. They also indicated that the aggregations resulted from NPs were related to the physical interaction of the PS NPs with platelet membranes, and a special mechanism involving the physical bridging of adjacent non-activated platelets was employed by 50 nm carboxylated PS NPs. In summary, MPs and NPs may increase the risk of platelet-driven events by a mechanism that induced or enhanced platelet aggregation, which is determined by their unique combination of size and surface chemistry.
Applications of omega-3 polyunsaturated fatty acid supplementation for sport performance
Published in Research in Sports Medicine, 2019
Jordan D. Philpott, Oliver C. Witard, Stuart D.R. Galloway
EPA is known to replace arachidonic acid in the phospholipid layer of platelet cell membranes following n-3PUFA ingestion (Lorenz, Spengler, Fischer, Duhm, & Weber, 1983). As a consequence, platelet aggregation may be reduced due to a reduction in levels of thromboxane A within the plasma. Platelets mediate the wound healing process via blood clotting. Thus, in theory a decrease in platelet aggregation may increase bleeding time. Consistent with this notion, a recent study also suggests that n-3PUFA supplementation may reduce platelet aggregation in healthy individuals and therefore increase bleeding time following surgery or lacerations (McEwen, Morel-Kopp, Chen, Tofler, & Ward, 2013). However, human studies examining the influence of n-3PUFA supplementation on bleeding time and severity have generally shown mixed results. A recent systematic review found no difference in bleeding risk with n-3PUFA supplementation in different populations, including athletes (Begtrup, Krag, & Hvas, 2017). However, the interpretation of this systematic review may be influenced by variations in the dose and duration of n-3PUFA supplementation between studies. Overall, although n-3PUFA supplementation may reduce platelet aggregation there appears to be no effect on bleeding rates following surgery. Therefore, unless athletes are ingesting a high dose of n-3PUFA, concerns over bruising and bleeding following an injury during sport appear unfounded.
Surface tension measurement of normal human blood samples by pendant drop method
Published in Journal of Medical Engineering & Technology, 2020
Siddharth Singh Yadav, Basant Singh Sikarwar, Priya Ranjan, Rajiv Janardhanan, Ayush Goyal
Yadav et al. [14] observed different patterns of stains with different samples. Later, they demonstrated that structure of pattern formation of stains strongly depends on blood surface tension. Along with surface tension and other aspects, the specific lines created in dried fluid micro-droplets have also been studied in literature thoroughly [15]. Berry et al. [16] demonstrated that surface tension of blood allows discovering purity and impurities of blood samples. They found that surface tension values are different for human disorders like breast cancers, fluorescent particles, and numerous blood dead cells. Baier et al. [17] observed different surface tension values with notable temperature and showed that the blood surface tension plays an important role to find out compatible biomaterials for blood flow and other blood-related events. Recently, Yadav et al. [18] reported that blood surface tension has potential to make a screening device to assess the health of the populace in theresource-limited conditions. Researchers [19] reported that surface tension of blood was found to be a critical parameters in the use of new synthetic materials for different quality control in abnormal blood like platelets count, haemoglobin level, red blood cell count and protein level. A blood cell disorder is a condition in which there is a problem with red blood cells, white blood cells, or the smaller circulating cells called platelets, which are critical for clot formation. Red blood cells transport oxygen to bodily organs and tissues. White blood cells help the body fight infections. Platelets help your blood to clot. Blood cell disorders impair the formation and function of one or more of these types of blood cells. In addition, body temperature varies according to the functionality of the body organism. Hence, surface tension of liquid–vapour interface of blood plays a vital role in many biological processes. However, the effect of temperature and haematocrit on liquid–vapour surface tension is needed to know the biological process at surface and interfaces [20].