Predicting the first site of relapse for cancerous tumors using protein expression profiles.

Myelination is one of the important stages of the nervous system (NS) development and regeneration. Understanding myelination is key to understanding certain diseases of the NS including healing after injuries. In a recent article by Huang et al (Nanotechnology. 2011;22(27):275101), the authors studied myelin structure at various stages of formation using a co-culture of Schwann cells and PC12 cells from a rat pheochromocytoma cell line. These were kept in a myelination medium and studied at 7, 12, 17, and 22 days. Indentation was used to assess the mechanical characteristics of the developing myelin. This was performed using a Berkovich diamond tip of 20 nm of radius. They observed that the optimal cell density PC12/ Schwann cells was 3:2. The myelination process began at day 12 in vitro (Figure 1), when Schwann cells express protein zero (P0). There are 3 stages in myelin structural development (Figure 2). At the latter stage (M-III), myelin becomes denser. Nano-indentation was performed every 5 nm on the axon. Displacements were measured and were a reflection of the myelin thickness. Measured displacements were 784 for M-I, 536 for M-II, and 833 nm for M-III. The work required to penetrate the myelin was -267 for M-I, 63 for M-II, and 301 mN nm for M-III. Resistance 1⁄4 work/ displacement and was—0.34, 0.12, and 0.36 mN respectively. The curves indicate the change in the mechanical properties of the myelin sheaths at various stages of development. Huang et al brought a better understanding of the myelination process using nano-technology to study the stiffness profile of myelinated axons. Development of various factors that influence the myelination process could be key in treating some demyelinating diseases such as GuillainBarré syndrome or multiple sclerosis. On the other hand, it may help develop strategies to promote healing of the central or peripheral NS.