ISSN:
1573-6865
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Synopsis Elastic fibres in histological sections have only a slightly higher affinity (than chromatin or cartilage matrix) for unpurified Orcein in acidified 70% ethanol, but the staining of elastic fibres is more exothermic (the heat of staining being in good agreement with publishedin vitro measurements), has a considerably higher activation energy, and is probably accompanied by a greater decrease in entropy. Experiments with purified dye fractions, and unpurified dye in 10% ethanol, were inconclusive, as it was not possible to prove unequivocally that equilibrium between dyebath and substrate had been achieved under these conditions. The results are consistent with the selectivity of orcein for elastic fibres under practical conditions being due to (a) the presence in elastic fibres of a relatively large number of dye-binding sites per unit volume, which probably bind by some non-ionic mechanism, (b) the relatively non-polar nature of elastic fibres, which repel cationic dye particles less than do tissue components that at low pH carry a positive charge, and (c) the low permeability of elastic fibres, so that dyeing, once achieved, is relatively resistant to alcoholic extraction. An alcoholic solvent for the dye enables strong solutions, and hence short staining times, to be used.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01003279
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