Original Paper

Reflectance Changes in Clotting Native Blood: Evidence of a Red Cell Process
Frank A. Greco

The Biophysical Laboratory, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, Mass., USA

Address of Corresponding Author

Pathophysiol Haemos Thromb 2007/2008;36:23-31 (DOI: 10.1159/000112636)

  Key Words

• Blood coagulation
• Erythrocyte
• Platelet
• Reflectance spectroscopy
• Coxibs

  Abstract

When broadband light illuminates clotting native blood, the reflectance at each wavelength traces a time course with four discernible regions. Clot formation occurs just before the second phase. Two wavelengths, 471 and 771 nm, were selected for more detailed study of the first two phases. Analysis of each time course in native blood demonstrates that both signals track a single process during the first phase, but distinct processes during the second. Experiments on citrated blood identified which blood components contribute to reflectance changes. Comparison of liquid and clotting blood reveals a single process during the first phase, entailing that rouleaux formation determines the time course at both wavelengths. Control experiments eliminate clot propagation and shape change of red cells or platelets as possible factors in the second phase. Exogenous ADP added to EDTA blood evokes the second-phase response at 471 but not 771 nm, a novel phenomenon that requires the presence of red cells. The descriptive name 'ADP-end-response' is suggested for this red cell process until it is further characterized. We propose that the ADP-end-response determines the 471-nm signal during the second phase of clotting native blood and depends upon platelets in the absence of exogenous ADP. The 771-nm signal reports fibrin cross-linking during the second phase. An earlier pilot study demonstrated that rofecoxib effects the 471-nm signal ex vivo, which indicates that reflectance spectroscopy may be useful in the assessment of drug effects on platelet-erythrocyte interactions.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

Frank A. Greco, MD, PhD
The Biophysical Laboratory, Edith Nourse Rogers Memorial Veterans Hospital
Research Service (151), 200 Springs Road
Bedford, MA 01730 (USA)
Tel. +1 781 687 3265, Fax +1 781 687 3527, E-Mail frank.greco2@med.va.gov

  Article Information

Received: March 13, 2007
Accepted after revision: August 9, 2007
Published online: March 06, 2008
Number of Print Pages : 9
Number of Figures : 2, Number of Tables : 1, Number of References : 24