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Sickle Cell Hemoglobin
Lisa Ho & Praise AustinDr. Robin W. Briehl
Albert Einstein College of Medicine
Red Blood Cell Round disc shape Transports oxygen
Sickle Cell Trait Sickle Cell Disease
Abnormal sickle shape Rigidity Cell Damage & Cell-Cell
Adhesion Hemolysis & Anemia
Background
Glutamic Acid Valine Deoxygenation Hydrophobic Interaction Polymerization into Stiff
Fibers Distorts shape & rigidifies
cells Induces Vaso-Occlusion
Fibers
Video camera Zeiss light microscope DIC Optics Epi-illumination light source
for photolysis of HbCO Potassium Phosphate buffer
(pH 7.2 at 0.1 M concentration)
Blood or Hb solution sample Gel sample
Methods
Fiber Visualization using 546nm light source
Differential Interference Contrast Microscopy
Can visualize objects smaller than diffraction limitation size
Splits the light into two different light beams
Wollaston prism The phase image facilitates
visualization of the fibers.
DIC Microscopy
VCR
Image Processor
Video Camera
Barrier Filter
Analyzer
546nm observation
436nm photolysis
Dichroic mirror
Hg arc
Field Diaphragm
Exciter Filter
CO
Hg arc
Wollaston prism
SlideWollaston prism Polarizer
I. The epi-illumination light source was activated
II. The light Intensity was altered to produce desired amount of deoxygenation and therefore of polymerization.
Mechanism
COHbS + hv HbS + CO
ProcedureEpi - illumination
Homogeneous Nucleation and Growth of Sickle Fibers
http://www.dailymotion.com/video/xacduc_copy-of-homogrow
Heterogeneous Nucleation and Fiber Growth
http://www.dailymotion.com/video/xacdss_heterogeneous-nucleation_school
Increase the delay time Conduct Rheological tests on Lab
grown Gels Clinical Studies on various
therapeutic treatments
Future
Enbury, S. H., Hebbel, R. P., Mohandas, N. & Steinberg, M. H. (1994). Sickle cell disease: basic principles and clinical practice. New York: Raven Press Ltd.
Dickerson, R. E. & Geis, I. (1983). Hemoglobin. California: The Benjamin/ Cummings Plublishing Company, Inc.
Wang, J. C., Turner, M. S., Agarwal, G., Kwong, S., Josephs, R., Ferrone, F. A. & Breihl, R. W. (2002). Micromechanics of isolated sickle cell hemoglobin fibers: bending moduli and persistence lengths. Journal of Molecular Biology, 315, 601-612.
Agarwal, G., Wang, J. C., Kwong, S., Cohen, S. M., Ferrone, F. A., Josephs, R. & Breihl, R. W. Sickle hemoglobin fibers: mechanisms of depolymerization. Journal of Molecular Biology, 322, 395-412.
Ferrone, F. A. (2004). Polymerization and sickle cell disease: a molecular view. Microcirculation, 11:2, 115-128
Breihl, R. W. (1997). Sickle cell hemoglobin. Encyclopedia of human biology, (Second Edition, Vol. 8, pp. 1-20). New York, Academic Press Inc.
Anfinsen, C. B., Edsall, J. T., Richards, F. M. & Eisenberg, D. S. (1987). Advances in protein chemistry. New York, Academic Press Inc.
References
Professor Robin W. Briehl, MD
Jiang Cheng Wang
Suzanna Kwong
Albert Einstein College of Medicine &
Staff
Dr. Sat Bhattacharya
Harlem Children Society
The audience
Acknowledgements