Transcript Sickle Cell Hemoglobin

Sickle Cell
Hemoglobin
Lisa Ho & Praise Austin
Dr. Robin W. Briehl
Albert Einstein College of Medicine
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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
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Glutamic Acid  Valine
Deoxygenation
Hydrophobic Interaction
Polymerization into Stiff Fibers
Distorts shape & rigidifies cells
Induces Vaso-Occlusion
http://www.dailymotion.com/video/xacdyf_sic
kling-and-unsickling
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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
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Fiber Visualization using 546nm light source
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Differential Interference Contrast Microscopy
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Can visualize objects smaller than diffraction
limitation size
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Splits the light into two different light beams
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Wollaston prism
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The phase image facilitates visualization of
the fibers.
Image
Processor
Video
Camera
VCR
Barrier Filter
Analyzer
Dichroic mirror
436nm photolysis
546nm
observation
Wollaston prism
Slide
Hg arc
Exciter Filter
CO
Field
Diaphragm
Wollaston prism
Polarizer
Hg arc
I.
II.
The epi-illumination light source was
activated
The light Intensity was altered to produce
desired amount of deoxygenation and
therefore of polymerization.
Mechanism
COHbS + hv  HbS + CO
http://www.dailymotion.com/video/xacduc_copy-of-homogrow
http://www.dailymotion.com/video/xacdss_heterogeneou
s-nucleation_school
http://www.dailymotion.com/video/xacdwi_en
dmelt
Help decipher how polymers grow
and dissolve
 Aim:
Inhibit growth
Facilitate dissolution
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Increase the delay time
Conduct Rheological tests on Lab
grown Gels
Clinical Studies on various therapeutic
treatments
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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.
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Professor Robin W. Briehl, MD
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Jiang Cheng Wang
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Suzanna Kwong
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Albert Einstein College of Medicine & Staff
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Dr. Sat Bhattacharya
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Harlem Children Society
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The audience
Any questions?