Sickle Cell Anemia

"First he had me reading about red blood cells and now I've got to read through these articles describing previous findings. What I really want to do is get started on my own experiments," lamented John to Christine, a fellow graduate student who was working in a different lab at Harvard.

"I know the feeling. It seems everyone goes through the same process. So what's in those articles?"

"The first one is a report from E. Vernon Hahn. I guess he was some kind of a surgeon practicing in Indianapolis. He states that if you take a tube of blood from a sickle-cell patient and allow it to sit undisturbed for a while, the cells at the bottom of the tube will become sickled while those at the top of the tube retain their normal shape."

"I wonder why only the bottom cells sickled?" posed Christine. "Do you suppose that the cells that sickle are heavier?"

"I'm not sure, but I don't think that weight is the critical issue. After he shook up the tube, the sickled cells returned to their normal shape."

"You're telling me that cells can return to their normal shape after they have sickled? I always thought it was a permanent change," Christine said.

"That's what I had thought. Actually, that may be a good thing. If this shape change is reversible, then maybe we have a better hope of finding an effective treatment."

Questions

1. How was the environment of the blood different at the top of the tube versus the bottom of the tube? Parameters to consider should include such things as: density of cells; concentration of nutrients, waste products, gases; pressure differences; and possible temperature differences.

2. How would shaking the tube alter the environment of the tube? Consider what would happen to the concentration of different molecules.

3. What environmental factor do you believe is responsible for causing the cells to sickle?

4. How would the repeated sickling and unsickling of the cells affect the average life span of red blood cells?

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