title: An improved method for staining cells of the endocrine polypeptide (APUD) series by masked metachromasia: application of the principle of 'fixation by excluded volume'.
abstract: Masked metachromasia is demonstrated by staining with a metachromatic basic dye, after acid hydrolysis of suitably fixed tissue. We report that the addition of 20% Carbowax 20M (an inert polyer, mol. wt. about 20,000) to the hydrolysis mixture improved the reaction. The improved method gives increased metachromasia , greater tolerance to variations in hydrolysis conditions, and demonstrates a greater proportion of cells--presumably due to a lower threshold of sensitivity. Lower molecular weight polymers (Carbowax 1000, Carbowax 6000) are less effective.
mesh_terms: D000818:Animals; D004285:Dogs; D007830:Larynx / Q000032:analysis / Q000166:cytology; D008722:Methods; D051379:Mice; D008856:Microscopy, Fluorescence; D009928:Organ Specificity; D010179:Pancreas / Q000032:analysis / Q000166:cytology; D010455:Peptides / Q000032:analysis*; D011108:Polymers; D051381:Rats; D013194:Staining and Labeling; D013961:Thyroid Gland / Q000032:analysis / Q000166:cytology; D013997:Time Factors
chemical_list: D010455:Peptides; D011108:Polymers