RAND R P, BURTON A C
Biophys J. 1964 Mar;4(2):115-35. doi: 10.1016/s0006-3495(64)86773-4.
The technique of Mitchison and Swann (1954) was modified for determining the resistance to deformation, or "stiffness," of the red cell membrane and the pressure gradient across the cell wall. It requires a measure of the pressure needed to suck a portion of the cell into a micropipette. Stiffness of hypertonically crenated cells was less than that of biconcave discs or hypotonically swollen cells. Crenated cells showed zero pressure gradient and a stiffness, probably due to pure bending, equivalent to 0.007 +/- 0.001 (SE) dynes/cm. Normal and swollen cells showed a pressure gradient of 2.3 +/- 0.8 (SE) mm H(2)O and a stiffness, due to bending and tension in the membrane, equivalent to 0.019 +/- 0.002 (SE) dynes/cm. No difference in stiffness was found between the rim and the biconcavity of the cell or between biconcave discs and hypotonically swollen cells. Micromanipulation showed that the membrane can withstand large bending strains but limited tangential strains (stretching). These results have significant implications in any theory explaining the cell shape. For example, the data give no indication that the physical properties of the membrane are different at the rim from those of the biconcavities, and the existence of a positive pressure in the normal cell is established.
米奇森和斯旺（1954年）的技术被改进用于测定红细胞膜的抗变形能力或“硬度”以及跨细胞壁的压力梯度。这需要测量将细胞的一部分吸入微量移液器所需的压力。高渗皱缩细胞的硬度小于双凹圆盘状细胞或低渗肿胀细胞的硬度。皱缩细胞显示零压力梯度和一种硬度，可能是由于单纯弯曲，相当于0.007±0.001（标准误）达因/厘米。正常细胞和肿胀细胞显示压力梯度为2.3±0.8（标准误）毫米水柱，并且由于膜中的弯曲和张力而具有的硬度相当于0.019±0.002（标准误）达因/厘米。在细胞的边缘和双凹面之间或双凹圆盘状细胞与低渗肿胀细胞之间未发现硬度差异。显微操作表明，膜能够承受大的弯曲应变但只能承受有限的切向应变（拉伸）。这些结果对任何解释细胞形状的理论都具有重要意义。例如，数据没有表明膜在边缘处的物理性质与双凹面处的不同，并且正常细胞中存在正压力得以确立。
