A new method of tissue processing that causes no shrinkage or distortion.
BACKGROUND
The routine method of tissue processing or dehydration usually causes shrinkage and/or distortion. More noticeable changes are seen in large specimens rich on hydrated tissues, such as embryos. Most likely this is due to the step-wise concentration change of the solvents.


METHODS
A new method of gradual solvent or medium exchange for tissue processing was developed. By using a peristaltic pump, pure solvent or embedding medium was added slowly to the processing chamber and the overflowing processed solution was slowly drained off. A computer spreadsheet program was used to calculate the concentration changes. After adding four to five times the processing volume of the solvent, the concentration of the adding solvent in the processing chamber could reach 98.15 to 99.32%. After reaching a desired endpoint, pure solvent could be used to replace the processing solution.


RESULTS
We compared microencapsulated pancreatic islets and liver tissue processed traditionally and with the new method. By using this design, a smooth linear and gradual change of the concentration of the processing solutions could be obtained. No shrinkage or distortion of tissues due to the dehydration artifact was noticed, and the tissue seemed to be ideally suited for accurate quantitative histologic measurements.


CONCLUSIONS
A very simple but efficient method for gradual solvent and medium exchange had been designed. This could efficiently prevent the shrinkage and distortion commonly produced by traditional tissue processing methods and prepare the tissue for quantitative histologic and pathologic studies.
Leu
F J
FJ
Department of Pathology, Tri-Service General Hospital, Taipei, Taiwan, R.O.C.
Chen
C F
CF
Sun
A M
AM
D000818:Animals; D016477:Artifacts; D002214:Capsules; D003681:Dehydration; D004285:Dogs; D005069:Evaluation Studies as Topic; D006652:Histological Techniques / Q000009:adverse effects; D007515:Islets of Langerhans; D008099:Liver; D008854:Microscopy, Electron; D051381:Rats; D017207:Rats, Sprague-Dawley; D012997:Solvents
D002214:Capsules; D012997:Solvents