Weight responses of tissue slices and albumin‐gelatin gels during formaldehyde fixation with observations upon the effects of pH

Abstract

Thin slices of rat liver, kidney, and M. rectus femoris and thin, flat pieces of albumin-gelatin gels (which approximated the tissue slices in mass, dimensions and protein content) were immersed in formalin solutions at various concentrations, in some cases with variable amounts of NaCl (0.11-0.25M) added, and in some cases buffered at pH values ranging from 3.5-7.0. The slices were weighed at frequent intervals for the first 20 hours of immersion. Weight changes occurred rapidly. With the exception of the neutral buffered formalin curves, three families of response curves were obtained for the three tissues. With both formalin and formalinsaline solutions weight gain was inversely proportional to the solute concentration, but the formaldehyde particles apparently are not involved osmotically. The total osmotic concentration of formalin solutions, therefore, is not a factor in the swelling or shrinking of tissue slices. The presence of contaminants could be responsible for the effective osmotic concentration observed with these solutions. The weight response of slices is influenced by the pH of the formalin. Although the response of the gel system to any particular solution was quantitatively greater, it was qualitatively the same as the tissue slice response.

Preservation de l'ultrastructure du sclerote de Sclerotinia tuberosa (Champignon Discomycete); Un modele pour la preparation des echantillons impermeables et heterogenes.

“…1978). Pour Bernard et Wynn (1964) le formaldehyde seul n'est pas osmotiquement actif. Pour Barnard (1976) l'effet osmotique du glutaraldeyde serait seulement la moitie de cc que son osmolarite laisserait prevoir.…”