In vitro systems and cultured cells as specimens for X-ray microanalysis

In vitro systems and cultured cells are recognized as useful systems in man y areas of biomedical research, including X-ray microanalysis. To be reliab le, in an vitro system should have an elemental composition close to that o f the tissue in situ, react in the same way to stimuli, and retain the in s itu regulation of ion transport. In the present paper, four of the most com monly used in vitro systems will be reviewed: incubated tissue slices (live r and pancreas), isolated glands (submandibular gland acini, sweat glands), primary cell cultures (sweat glands, endometrium), and cell lines (the col on cancer cell line T84, immortalized sweat gland cells). Incubation of tis sue slices of liver in Krebs-Ringers buffer caused a significant increase i n Na and Cl and a decrease in K. Initially, these changes were also observe d in the pancreas, but here the values gradually returned to normal. Isolat ed submandibular gland acini, and isolated sweat gland ducts and coils reac t in a similar way to stimulation as their in situ counterparts. In primary cultures of coil cells, however, part of the cell population acquires diff erent ion transport characteristics. Technically simplest is the use of cel l lines originating from cancer cells (e.g., the T84 cell line) and immorta lized cell lines. X-ray microanalysis not only confirms data on ion transpo rt obtained with other techniques, but adds the possibility to investigate the presence of subpopulations within a culture.