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29 December 1998 Low-power laser irradiation of blood inhibits platelet function: role of cyclic GMP
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The aim of the present work was to investigate effect of low power laser irradiation (LPLI) on platelet function in vitro. He-Ne laser (Optronix, USA; (lambda) - 632.8 nm, output power - 7 mW) was employed. Platelet adhesion and aggregation in whole blood (WB) under defined shear conditions were assayed by a Cone and Plate(let) Analyzer. Platelet activation was evaluated by flow cytometry. Level of platelet cGMP was estimated by immunoenzyme assay. Experiments performed showed that LPLI of WB resulted in decrease of platelet deposition on extracellular matrix at high shear rate (1300 s-1). Similar results were obtained using surfaces precoated with either collagen type I or von Willebrand factor. LPLI inhibited fibrinogen binding as well as P-selectin expression on the platelet membrane, induced by thrombin analogue. It was found out that primary acceptor of laser energy responsible for the effect on platelets was located in platelets themselves and not in blood plasma or in other blood cells. LPLI of gel- filtered platelets resulted in increase of intracellular level of cGMP both in the absence and in presence of izobutylmethylxantine (phosphodiesterase inhibitor) suggesting stimulation of synthesis rather than destruction of cGMP under the influence of LPLI. It is suggested that guanylate cyclase and/or NO-synthase might serve as primary acceptors of He-Ne laser light in platelets.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alexander G. Brill, Gregory E. Brill, Boris Shenkman, Ilya Tamarin, Rima Dardik, David Varon, and Naphtali Savion "Low-power laser irradiation of blood inhibits platelet function: role of cyclic GMP", Proc. SPIE 3569, Effects of Low-Power Light on Biological Systems IV, (29 December 1998);

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