Latest Research News on Blood Plasma: Jan 2021
Antioxidant defenses and lipid peroxidation in human blood plasma
The temporal disappearance in human blood plasma of endogenous antioxidants in relation to the appearance of various classes of lipid hydroperoxides measured by HPLC postcolumn chemiluminescence detection has been investigated under two types of oxidizing conditions. Exposure of plasma to aqueous peroxyl radicals generated at a constant rate leads immediately to oxidation of endogenous ascorbate and sulfhydryl groups, followed by sequential depletion of bilirubin, urate, and alpha-tocopherol. Stimulating polymorphonuclear leukocytes in plasma initiates very rapid oxidation of ascorbate, followed by partial depletion of urate. Once ascorbate is consumed completely, micromolar concentrations of hydroperoxides of plasma phospholipids, triglycerides, and cholesterol esters appear simultaneously, even though sulfhydryl groups, bilirubin, urate, and alpha-tocopherol are still present at high concentrations. Nonesterified fatty acids, the only lipid class in plasma not transported in lipoproteins but bound to albumin, are preserved from peroxidative damage even after complete oxidation of ascorbate, most likely due to site-specific antioxidant protection by albumin-bound bilirubin and possibly by albumin itself. Thus, in plasma ascorbate and, in a site-specific manner, bilirubin appear to be much more effective in protecting lipids from peroxidative damage by aqueous oxidants than all the other endogenous antioxidants. Hydroperoxides of linoleic acid, phosphatidylcholine, and cholesterol added to plasma in the absence of added reducing substrates are degraded, in contrast to hydroperoxides of trilinolein and cholesterol linoleate. These findings indicate the presence of a selective peroxidase activity operative under physiological conditions. Our data suggest that in states of leukocyte activation and other types of acute or chronic oxidative stress such a simple regimen as controlled ascorbate supplementation could prove helpful in preventing formation of lipid hydroperoxides, some of which cannot be detoxified by endogenous plasma activities and thus might cause damage to critical targets. 
Ascorbate is an outstanding antioxidant in human blood plasma
We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols greater than bilirubin greater than urate greater than alpha-tocopherol and that detectable lipid peroxidation starts only after ascorbate has been consumed completely. In this paper, we show that it is indeed ascorbate that completely protects plasma lipids against detectable peroxidative damage induced by aqueous peroxyl radicals and that ascorbate is the only plasma antioxidant that can do so. Plasma devoid of ascorbate, but no other endogenous antioxidant, is extremely vulnerable to oxidant stress and susceptible to peroxidative damage to lipids. The plasma proteins’ thiols, although they become oxidized immediately upon exposure to aqueous peroxyl radicals, are inefficient radical scavengers and appear to be consumed mainly by autoxidation. Our data demonstrate that ascorbate is the most effective aqueous-phase antioxidant in human blood plasma and suggest that in humans ascorbate is a physiological antioxidant of major importance for protection against diseases and degenerative processes caused by oxidant stress. 
Exosomal-like vesicles are present in human blood plasma
Exosomes are small membrane vesicles (50–90 nm in diameter) secreted by most hematopoietic cells. We provide here the first evidence for the presence of exosomes in vivo, in the blood. Plasma samples of all healthy donors tested (n = 15) contain vesicles that are similar in shape, size and density to the previously described exosomes. They were clearly identified by electron microscopy after isolation by differential ultracentrifugation or immunoisolation with CD63-coated latex beads. We performed their biochemical characterization by western blot analysis and by flow cytometry after vesicle adsorption onto latex beads using a panel of mAbs. We observed that these plasma-derived vesicles contain tetraspanin molecules such as CD63, CD9, CD81 as well as class I and class II MHC molecules and Lamp-2 (i.e. proteins that are known to be enriched in exosomes). In addition, these vesicles float on sucrose gradient at a density similar to exosomes. Our results demonstrate that blood is a physiological fluid for exosome circulation in the body, suggesting their role in cell–cell or organ–organ communications as carriers for molecules that need to reach distant cell targets. 
In-vitro Measurement of Glucose Concentration in Human Blood Plasma Mixed Intralipid Phantom Samples by Using Modulated Ultrasound and Infrared Light
Non-invasive blood glucose measurement is one of most innovative domain in Biomedical Engineering. Multiple methodologies have-been introduced over last few decades to fulfil the clinical requirement for non-invasive glucose measurement in human beings, however, without a successful breakthrough. This research article uses modulated ultrasound with infrared light-based technique to study glucose-induced variations in human blood plasma mixed IntralipidTM phantom samples using infrared light of 940 nm and 40 kHz central frequency based ultrasonic transmitter unit. The test uses blood samples of 30 study subjects during oral glucose tolerance test and fasting, postprandial and random stages based blood glucose tests respectively. The result as obtained from oral glucose tolerance tests and fasting, postprandial and random stages blood glucose tests showed peak amplitude values in Fast Fourier Transform domain varies in corresponding to blood glucose levels in in-vitro samples. The Bland Altman plot, Error Grid and statistical analysis represent the potentiality and feasibility of our technique for non-invasive blood glucose measurement. 
Detection of Prethrombin 1 in Human Blood Plasma
Background: Prethrombin 1 is one of prothrombin derivatives which appears in the presence of thrombin in vitro. However, existence of prethrombin 1 in vivo remained questionable. The aim of present work was to detect of prethrombin 1 in vivo at abdominal aortic aneurysm, hip replacement after fracture and stroke.
Methodology: Blood plasma samples of patients with abdominal aortic aneurysm, hip replacement after fracture, stroke, and patients which were treated with warfarine were collected. Detection of prethrombin 1 was completed using three independent approaches: combination of prothrombin index and ecamulin (ecarin) index; the APTT-test modified by addition of exogenous prothrombin; Western-blotting of blood plasma using polyclonal antibody to prothrombin.
Results: Prethrombin 1 presence in patients’ blood plasma at studied pathologies was proven. Inactive prothrombin (descarboxy-prothrombin), but not prethrombin 1 was found in blood plasma of patients which were treated with warfarine. Developed approach can be used for testing the prethrombin 1 in clinical diagnostics.
Conclusion: Prethrombin 1 at different pathologies, accompanied by coagulation disorders was detected in patients’ blood plasma directly. 
 Frei, B., Stocker, R. and Ames, B.N., 1988. Antioxidant defenses and lipid peroxidation in human blood plasma. Proceedings of the National Academy of Sciences, 85(24), pp.9748-9752.
 Frei, B., England, L. and Ames, B.N., 1989. Ascorbate is an outstanding antioxidant in human blood plasma. Proceedings of the National Academy of Sciences, 86(16), pp.6377-6381.
 Caby, M.P., Lankar, D., Vincendeau-Scherrer, C., Raposo, G. and Bonnerot, C., 2005. Exosomal-like vesicles are present in human blood plasma. International immunology, 17(7), pp.879-887.
 Srivastava, A., Koushik Chowdhury, M., Sharma, S. S. and Sharma, N. (2016) “In-vitro Measurement of Glucose Concentration in Human Blood Plasma Mixed Intralipid Phantom Samples by Using Modulated Ultrasound and Infrared Light”, Biotechnology Journal International, 13(1), pp. 1-14. doi: 10.9734/BBJ/2016/24861.
 Korolova, D., Chernyshenko, V., Platonova, T., Chernyshenko, T. and Lugovskoy, E. (2016) “Detection of Prethrombin 1 in Human Blood Plasma”, International Blood Research & Reviews, 5(2), pp. 1-7. doi: 10.9734/IBRR/2016/24683.