Fathi Narges, Moradi Ali-Reza, Habibi Mehdi, Vashaee Daryoosh, Tayebi Lobat
Department of Physics, University of Zanjan, PO Box 45195-313, Zanjan, Iran.
Biomed Opt Express. 2013 May 24;4(6):950-7. doi: 10.1364/BOE.4.000950. Print 2013 Jun 1.
Myelin figures (MFs) are cylindrical multilamellar lipid tubes that can be found in various healthy and diseased living cells. Their formation and dynamics involve some of the most mysterious configurations that lipid molecules can adopt under certain conditions. They have been studied with different microscopy methods. Due to the frequent coiling of their structure, the usual methods of microscopy fail to give precise quantitative information about their dynamics. In this paper, we introduced Digital Holographic Microscopy (DHM) as a useful method to calculate the precise dynamical volume, thickness, surface and length of the myelin figures. As an example of DHM imaging of myelin figures, their structure and growth rate in the presence and absence of temperature gradient have been studied in this work. We showed that the thickness of a myelin figure can be changed during the first few seconds. However, after approximately ten seconds, the thickness stabilizes and does not alter significantly. We further studied the effect of the thermal gradient on the length growth. The calculation of the length growth from the measurement of the myelin figure volume shows that the length (L) grows in time (t) as [Formula: see text]at the early stage of the myelin protrusion in both the presence and the absence of the thermal gradient. However, thermal gradient facilitates the growth and increases its rate.
髓鞘样结构（MFs）是圆柱形的多层脂质管，可在各种健康和患病的活细胞中发现。它们的形成和动态变化涉及脂质分子在某些条件下能够呈现的一些最神秘的构型。人们已经使用不同的显微镜方法对它们进行了研究。由于其结构频繁盘绕，常规显微镜方法无法提供有关其动态变化的精确定量信息。在本文中，我们引入了数字全息显微镜（DHM）作为一种计算髓鞘样结构精确动态体积、厚度、表面积和长度的有用方法。作为髓鞘样结构DHM成像的一个例子，在这项工作中研究了其在有和没有温度梯度情况下的结构和生长速率。我们表明，髓鞘样结构的厚度在最初几秒内会发生变化。然而，大约十秒后，厚度稳定下来，不再有显著变化。我们进一步研究了热梯度对长度生长的影响。根据髓鞘样结构体积的测量计算长度生长情况表明，在有和没有热梯度的情况下，在髓鞘突出的早期阶段，长度（L）随时间（t）的变化为[公式：见原文]。然而，热梯度促进了生长并提高了其速率。
