Patients with sickle cell disease have mutant hemoglobin proteins that form long, stiff fibers inside red blood cells. Now, researchers propose a mathematical model to explain the persistent stability of these deadly fibers. The theory suggests that an inherent "twistiness" in the strands that make up the fibers could be the key to their durability and possibly to new treatments.

Physical Review Focus: http://focus.aps.org/story/v11/st12
Journal article: http://link.aps.org/abstract/PRL/v90/e128103

2) How treatments affect cancer growth
S. C. Ferreira Jr., M. L. Martinsy, M. J. Vilela
Physical Review E (to appear)

Chemotherapeutic strategies use quite different means to prevent cancer growth. Cytotoxic treatments directly kill cancer cells (and take some healthy cells with them). Antimitotic treatments do not kill cancer cells but stop the cell cycle at specific checkpoints. This paper looks at the differences these strategies have on the structure of cancerous growths by using computer models. For cytotoxic strategies, tumors can be completely eradicated, cease their growth or grow continuously, depending on the frequency and efficiency of individual treatments. However mitotic strategies cause a distinct change in the patterns of tumor growth. The types of changes seen are similar to when bacterial colonies exposed to non-lethal concentrations of antibiotics exhibit drastic changes in their growth patterns. Seeing as this behavior has not yet been seen in laboratory, the authors suggest that these observing these structural transitions may give important information about treatment efficacy. The authors are currently conducting some of those laboratory studies.

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Contact: David Harris
harris@aps.org
301-209-3238
American Physical Society
1-Apr-2003