Going through archival electron micrographs of alveolar type II cells has been an interesting study. The purpose of the review is to gain insight into what is the explanation for some very interesting, highly organized granules (protein accumulations) that are found in some alveolar type II cells.  Of about 8 species examined so far (rat, mouse, owl monkey, rhesus monkey, dog, ferret, guinea pig, hamster  – even one human case) these bodies have been found in only three species. Dog is one, though in dog they are quite rare, and very small and not nearly as developed as found in ferret and guinea pig.

Most of the archival electron micrographs are tissues fixed in a double aldehyde fluid, in various buffers and at reasonably constant concentrations of glutaraldehyde, around 2.5%.  This tissue however was fixed in osmium tetroxide… thus verifying pretty much that the cisternal body granules are NOT just an artifact of aldehyde fixation.  So this image of a dog alveolar type II cell is not that great a micrograph, but it does show a small, typical style dog intracisternal body granule, with a similar periodicity and banding as found in aldehyde fixed material.

Upper image shows the mostly unretouched (i changed contrast, and took out a few scratches but did not change any data) and the bottom is a highly contrast enhanced crop of the upper image, and i have used the burn tool in photoshop to highlight the periodicity of the middle band (as also seen in many other micrographs posted in this blog).  The ribosome standard I called 27 nm in diameter, which makes the dotted periodicity of the central band of the cisternal body about 17 nm in diameter (also shown as a red dot) and the space between those 17 nm dark protein dots is a distance (made from 12 adjacent measurements) a mean of @ 32 nm.  Band across the body is close to the 100 nm that has been found in other instances in ferret and guinea pig and is presumed to be a collection of some multimer of surfactant protein A.