This paper describes the shape changes and shape transformations observed in human red cells heated for 2 min. to 48, 50 and 52° C.
The first change observed is an irregularity of the cell; this is followed by sphering, but the spherical forms can be turned into irregularly shaped disks again by the addition of serum albumin. The sphering is accordingly part of a reversible disk-sphere transformation due to the loss of a (recoverable) anti-sphering substance from the cells. At a slightly higher temperature 50°C.) fragmentation of the cells occurs with the production of fragments which are also capable of undergoing something equivalent to a disk-sphere transformation. The properties upon which the shape transformations depend are therefore not necessarily dependent on the integrity of the red cell as a unit.
The fragments derived from the cell may be unequally haemoglobinized, and the Hb is usually lost in a step-wise, as opposed to an all-or-none, manner. Taken together with the loss of anti-sphering substance and an accompanying loss of potassium from the cells, the shape changes preceding fragmentation and the step-wise loss of Hb suggest that the phenomena observed in the heated red cell are part of a process of disintegration of a plastic Hb-bearing ‘solid’.