A new method for studying platelets, based upon the low-angle light scattering technique. 2. Application of the method in experimental toxicology and clinical pathology

Abstract

A new method for studying platelets based on low-angle light scattering has been applied to studies in experimental toxicology and clinical pathology, using animal and human platelets. Index EC50for ADP within control groups was estimated to be in the range of 100–180 nmol l–1(healthy men, rabbits, rats). The refractory state of platelets was obtained by use ADP or ATP concentrations that just caused platelet activation. The time constant and the half-cycle of the refractory state of platelets were calculated. Kinetic parameters of platelet aggregation at interference of hemostasis (rabbit) and the influence of the age factors on the aggregation indices of platelets (rat) were studied. The method of low-angle light scattering was used as a diagnostic tool in experimental low-level intoxication by organophosphates and for interpretation of the pathogenesis of delayed effects. In human patients with ischemic heart disease or with prosthetic heart valves, significant changes in the functional state of platelets were observed. A model for cooperative binding of receptors with ligands on platelets from pregnant women with preeclampsia was developed.

Markers and Biomarkers of Endothelium: When Something Is Rotten in the State

“…In another study, chlorpyrifos over a wide concentration range showed no effect on isolated thoracic aorta, though plasma AChE activity was decreased, while LDH, ALT, GGT, and AST activities, together with plasma NO level, were increased in the chlorpyrifos group [199]. In our studies, we also paid attention to damage of the vascular endothelium in development of OP-induced delayed pathology [192,200,201]. We were the first to suggest that thrombotic microangiopathic disorders, resulting from endothelial damage, could be the primary reason for development of delayed effects of OP intoxication; the significance of this kind of disorders has been re-estimated over recent years [3].…”

Angiotensin II–Mediated Microvascular Thrombosis

“…On the 15 th day following micro-osmotic pump implantation, the cremaster muscle prepared for intravital microscopic observation and microvascular thrombosis was induced by the light/dye method, as previously described 17. Thrombus formation was quantified by determining: 1) the time of onset of platelet deposition/aggregation within the microvessel (onset time), and 2) the time required for complete flow cessation for ≥30 sec (cessation time) after light/dye injury.…”

“…Platelet rich plasma (PRP) collected from mice was used to quantify AngII- and thrombin-induced platelet aggregation using a low-angle light scattering technique, as previously described 17. For a more detailed description of these procedures, see the online Data Supplement.…”

Necrotic and apoptotic volume changes of red blood cells investigated by low‐angle light scattering technique

“…We have previously reported on a low-angle light scattering technique for investigating biological cells. The theoretical and experimental foundations of this methodology have been described, based mostly upon studies on blood platelets [14][15][16]. Ehrlich ascite tumor cells have also been the subject for investigation of intracellular signalling systems and ion channels using this technique [17].…”