scholarly journals THE INHIBITION OF HUMAN PLATELET AGGREGATION BY A LOW-MOLECULAR WEIGHT CHITOSAN

2018 ◽  
Vol XXIII ◽  
pp. 55-65
Author(s):  
Natalia N. Drozd ◽  
Yulia S. Logvinova ◽  
Balzhima Ts. Shagdarova ◽  
Alla V. Il’ina ◽  
Valery P. Varlamov
Keyword(s):  
Molecular Weight ◽  
Platelet Aggregation ◽  
Positive Charge ◽  
Human Platelet ◽  
Low Molecular Weight ◽  
Chitosan Derivatives ◽  
Human Platelet Aggregation ◽  
Low Molecular Weight Chitosan ◽  
Aggregation Of Platelets

Chitosan derivatives were obtained by chemical (MW of 6 kDa, DD 99% - Ch6/99; MW13 kDa, DD 98% - Ch13/98) and enzymatic (MW of 5 kDa, DD 85% - Ch5/85; MW of 10 kDa, DD 85% - Ch10/85) depolymeri-sation of chitosan with a MW of 334 and 1000 kDa. Chitosan derivatives (almost identical MW pairs and different DD) possessed insignificant an-ticoagulant activity, did not promote human platelet aggregation and re-duced ADP or collagen-induced platelet aggregation. The studied sam-ples at a concentration of 2 mg/ml reduced the aggregation of platelets more than twice induced in 2x10-6M and 1x10-5M concentrations; at weak activation in 2x10-6M, the Ch10/85 sample was the most effective. The Ch6/99 and Ch13/98 samples were 20 times more effective at the inhibi-tion of collagen-induced platelet aggregation than the Ch10/85 sample. The latter can be explained by the greater value of positive charge (DD) and polydispersity (Mw/Mn) of chitosan samples obtained by chemical de-polymerisation.

Searching for synergistic effects of low-molecular weight chitosan derivatives, chitosan and copper nanoparticles for wound healing ointment

2021 ◽  
Vol 12 (3) ◽  
pp. 035016
Author(s):  
Natalya Nikolaevna Glushchenko ◽  
Olga Alexandrovna Bogoslovskaya ◽  
Balzhima Tsyrendorzhievna Shagdarova ◽  
Alla Victorovna Il’ina ◽  
Irina Pavlovna Olkhovskaya ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Wound Healing ◽  
Copper Nanoparticles ◽  
Synergistic Effects ◽  
Low Molecular Weight ◽  
Chitosan Derivatives ◽  
Low Molecular Weight Chitosan

Surface Activity of Some Low Molecular Weight Chitosan Derivatives

2013 ◽  
Vol 8 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Khaldoun Al-Sou’oda ◽  
Rasha Abu-Falaha ◽  
Mayyas Al-Remawi
Keyword(s):  
Molecular Weight ◽  
Surface Activity ◽  
Low Molecular Weight ◽  
Chitosan Derivatives ◽  
Low Molecular Weight Chitosan

scholarly journals Low concentrations of lipid hydroperoxides prime human platelet aggregation specifically via cyclo-oxygenase activation

1997 ◽  
Vol 325 (2) ◽  
pp. 495-500 ◽  
Author(s):  
Catherine CALZADA ◽  
Evelyne VERICEL ◽  
Michel LAGARDE
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Lipid Peroxides ◽  
Human Platelets ◽  
Lipid Hydroperoxides ◽  
Cellular Functions ◽  
Human Platelet Aggregation ◽  
Low Concentrations ◽  
Oxygenase Activity ◽  
Aggregation Of Platelets

There is mounting evidence that lipid peroxides contribute to pathophysiological processes and can modulate cellular functions. The aim of the present study was to investigate the effects of lipid hydroperoxides on platelet aggregation and arachidonic acid (AA) metabolism. Human platelets, isolated from plasma, were incubated with subthreshold (i.e. non-aggregating) concentrations of AA in the absence or presence of hydroperoxyeicosatetraenoic acids (HPETEs). Although HPETEs alone had no effect on platelet function, HPETEs induced the aggregation of platelets co-incubated with non-aggregating concentrations of AA, HPETEs being more potent than non-eicosanoid peroxides. The priming effect of HPETEs on platelet aggregation was associated with an increased formation of cyclo-oxygenase metabolites, in particular thromboxane A2, and was abolished by aspirin, suggesting an activation of cyclo-oxygenase by HPETEs. It was not receptor-mediated because the 12-HPETE-induced enhancement of AA metabolism was sustained in the presence of SQ29,548 or RGDS, which blocked the aggregation. These results indicate that physiologically relevant concentrations of HPETEs potentiate platelet aggregation, which appears to be mediated via a stimulation of cyclo-oxygenase activity.

Pharmacology Of 12-Deoxyphorbol Phenyl Acetate (12-DOPP) Induced Human Platelet Aggregation

1981 ◽  
Author(s):  
J Westwick ◽  
E M Williamson ◽  
F J Evans ◽  
V V Kakkor
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Divalent Cations ◽  
Dienoic Acid ◽  
Free Radical Scavengers ◽  
Phenyl Acetate ◽  
Lipoxygenase Inhibitor ◽  
Human Platelet Aggregation ◽  
Induced Aggregation ◽  
Aggregation Of Platelets

12-DOPP (0.1 to 3.6µM) induced human platelet aggregation which was dependent upon the presence of divalent cations, intracellular level of C-AMP and an intact microtubular system in common with other aggregating agents. However, the small amount of platelet secretion and thromboxane (Tx) B2 synthesis did not contribute to 12-DOPP induced platelet aggregation as neither the Tx/endoperoxide antagonists pinane A2 (0.001-0.004mM) and trimethoquinone (0.01-0.1mM), the Tx synthesis inhibitors clotrimazole (0.1 to 0.8mM) and 9, 11, aza-prosta-5-13 dienoic acid (0.002-0.1) nor the cyclo-oxygenase inhibitor indomethacin (0.03-0.1mM) inhibited 12-DOPP induced aggregation. Furthermore the free radical scavengers aminopyrine (0.2-2.0mM), thioanisole (0.2-2.0mM) and butylated hydroxy toluene (0.07-1.4mM); the lipoxygenase inhibitor phenidone (0.5mM) and the leucotriene B and C antagonist FPL55712 (0.005-0.06mM) failed to modify 12-DOPP induced aggregation.However compounds which are thought to act as phospholipase inhibitors bromophenacyl bromide (0.3mM), mepracrine (0.20mM) and propanolol (0.2mM) were found to be effective inhibitors of 12-DOPP induced aggregation as well as the so- called calmodulin antagonists imipramine (0.12mM), desmethy- 1imipramine (0.033mM), promethazine (0.1mM) and trifluoperazine (0.35mM).The aggregation induced by 12-DOPP involves a direct effect upon platelets followed by the release of unknown substances probably phospholipids, which induce further aggregation of platelets.

scholarly journals Characterization of a platelet membrane protein of low molecular weight associated with platelet activation following binding by monoclonal antibody AG-1

Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 743-751
Author(s):  
JL Miller ◽  
JM Kupinski ◽  
KO Hustad
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Human Platelet ◽  
Platelet Membrane ◽  
Antibody Concentration ◽  
Lag Phase ◽  
Low Molecular Weight ◽  
Glycoprotein Ib ◽  
Platelet Surface

With the exception of the major platelet glycoproteins IIb/IIIa and Ib, which function as receptors for fibrinogen and von Willebrand factor, little is presently known regarding the possible role of other platelet surface proteins in mediating platelet aggregation. We report the production of a murine monoclonal antibody (AG-1) recognizing human platelet membrane surface protein of relatively low molecular weight (mol wt) that may be involved in this process. AG-1 added to human platelet-rich plasma induces dense granule secretion and aggregation, with lag phase and maximal extent of aggregation dependent on antibody concentration. Aggregation induced by AG-1 is inhibited by AG-1 Fab fragments, indicating that the response is not Fc receptor-mediated. Although AG-1 continues to produce platelet shape change in the presence of EDTA, aggregation is fully inhibited and appears to be mediated by fibrinogen binding to glycoproteins IIb/IIIa. AG-1 is a potent stimulus of thromboxane formation, but full inhibition of thromboxane production by 30 mumol/L indomethacin does not significantly inhibit platelet aggregation induced by 25 micrograms/mL AG-1, indicating that aggregation induced by AG-1 may proceed by way of an endoperoxide-independent pathway. Quantitation of AG-1 Fab binding to platelets reveals approximately 65,000 binding sites per platelet. When intact platelets are radioiodinated, immunoprecipitation of NP-40 lysates by AG-1 reveals an intensely labeled protein with an apparent mol wt of approximately 21,000 daltons, and several additional bands in the mol wt range of 22,000 to 28,000 daltons, all sharing the AG-1 epitope. These bands appear to be distinct from glycoprotein IX or from the beta-chains of glycoprotein Ib or IIb. Finally, studies with platelets labeled by the periodate-[3H]borohydride procedure suggest the possibility of complex formation between subpopulations of glycoprotein Ib and the low-mol-wt glycoproteins recognized by AG-1.

scholarly journals Characterization of a platelet membrane protein of low molecular weight associated with platelet activation following binding by monoclonal antibody AG-1

Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 743-751 ◽  
Author(s):  
JL Miller ◽  
JM Kupinski ◽  
KO Hustad
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Human Platelet ◽  
Platelet Membrane ◽  
Antibody Concentration ◽  
Lag Phase ◽  
Low Molecular Weight ◽  
Glycoprotein Ib ◽  
Platelet Surface

Abstract With the exception of the major platelet glycoproteins IIb/IIIa and Ib, which function as receptors for fibrinogen and von Willebrand factor, little is presently known regarding the possible role of other platelet surface proteins in mediating platelet aggregation. We report the production of a murine monoclonal antibody (AG-1) recognizing human platelet membrane surface protein of relatively low molecular weight (mol wt) that may be involved in this process. AG-1 added to human platelet-rich plasma induces dense granule secretion and aggregation, with lag phase and maximal extent of aggregation dependent on antibody concentration. Aggregation induced by AG-1 is inhibited by AG-1 Fab fragments, indicating that the response is not Fc receptor-mediated. Although AG-1 continues to produce platelet shape change in the presence of EDTA, aggregation is fully inhibited and appears to be mediated by fibrinogen binding to glycoproteins IIb/IIIa. AG-1 is a potent stimulus of thromboxane formation, but full inhibition of thromboxane production by 30 mumol/L indomethacin does not significantly inhibit platelet aggregation induced by 25 micrograms/mL AG-1, indicating that aggregation induced by AG-1 may proceed by way of an endoperoxide-independent pathway. Quantitation of AG-1 Fab binding to platelets reveals approximately 65,000 binding sites per platelet. When intact platelets are radioiodinated, immunoprecipitation of NP-40 lysates by AG-1 reveals an intensely labeled protein with an apparent mol wt of approximately 21,000 daltons, and several additional bands in the mol wt range of 22,000 to 28,000 daltons, all sharing the AG-1 epitope. These bands appear to be distinct from glycoprotein IX or from the beta-chains of glycoprotein Ib or IIb. Finally, studies with platelets labeled by the periodate-[3H]borohydride procedure suggest the possibility of complex formation between subpopulations of glycoprotein Ib and the low-mol-wt glycoproteins recognized by AG-1.

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