Theory of histological staining: why and how staining happens

No abstract available

Theory of histological staining: why and how staining happens

No abstract available

The failure to specify sources of dyes, chromogens and fluorescent probes: an analysis and some proposals for action

No abstract available

The misnaming of dyes and fluorescent probes - a survey of practical problems arising from errors and ambiguities in nomenclature seen in current documents and some remedial proposals

Errors and ambiguities in the nomenclature of dyes and fluorescent probes are surveyed and illustrated by case examples. The unfortunate practical consequences of such mistakes are summarized. Origins and causes of such errors are discussed. Recommendations are appended for end-users, vendors, and editors of learned journals, and those who referee their manuscripts

How Romanowsky stains work and why they remain valuable — including a proposed universal Romanowsky staining mechanism and a rational troubleshooting scheme

An introduction to the nomenclature and concept of “Romanowsky stains” is followed by a brief account of the dyes involved and especially the crucial role of azure B and of the impurity of most commercial dye lots. Technical features of standardized and traditional Romanowsky stains are outlined, e.g., number and ratio of the acidic and basic dyes used, solvent effects, staining times, and fixation effects. The peculiar advantages of Romanowsky staining are noted, namely, the polychromasia achieved in a technically simple manner with the potential for stain intensification of “the color purple.” Accounts are provided of a variety of physicochemically relevant topics, namely, acidic and basic dyeing, peculiarities of acidic and basic dye mixtures, consequences of differential staining rates of different cell and tissue components and of different dyes, the chemical significance of “the color purple,” the substrate selectivity for purple color formation and its intensification in situ due to a template effect, effects of resin embedding and prior fixation. Based on these physicochemical phenomena, mechanisms for the various Romanowsky staining applications are outlined including for blood, marrow and cytological smears; G-bands of chromosomes; microorganisms and other single-cell entities; and paraffin and resin tissue sections. The common factors involved in these specific mechanisms are pulled together to generate a “universal” generic mechanism for these stains. Certain generic problems of Romanowsky stains are discussed including the instability of solutions of acidic dye–basic dye mixtures, the inherent heterogeneity of polychrome methylene blue, and the resulting problems of standardization. Finally, a rational trouble-shooting scheme is appended

Report on the 2nd workshop on fluorescence chemosensors and bioimaging, Dalian, China: one participant’s view

I was invited to this Workshop, because I have published papers on the mechanisms of action of small molecule fluorescent probes used with living cells. The Workshop provided an opportunity to interact with some significant figures in the chemosensor and bioimaging field from across the planet; to spend time with a large, friendly and active group of local investigators and their graduate students; and to take a brief look at a vibrant modern city. Many scientific connections were made and collaborations planned for the Biological Stain Commission and for my own future work

Staining by numbers: a tool for understanding and assisting use of routine and special histopathology stains

No abstract available

Biological staining: mechanisms and theory

New staining techniques continue to be introduced, and older ones continue to be used and improved. Several factors control specificity, selectivity and visibility of the end product in any procedure using dyes, fluorochromes, inorganic reagents or histochemical reactions applied to sections or similar preparations. Local concentration of the tissue target often determines the intensity of the observed color, as does the fine structure within the object being stained, which may facilitate or impede diffusion of dyes and other reagents. Several contributions to affinity control the specificity of staining. These include electrical forces, which result in accumulation of dye ions in regions of oppositely charged tissue polyions. Weaker short-range attractions (hydrogen bonding, van der Waals forces or hydrophobic bonding, depending on the solvent) hold dyes ions and histochemical end products in contact with their macromolecular substrates. Nonionic forces can also increase visibility of stained sites by causing aggregation of dye molecules. Covalent bonds between dye and tissue result in the strongest binding, such as in methods using Schiff's reagent and possibly also some mordant dyes. The rate at which a reagent gains access to or is removed from targets in a section or other specimen affect what is stained, especially when more then one dye is used, together or sequentially. Rate-controlled staining is greatly influenced by the presence and type of embedding medium, such as a resin, that infiltrates the tissue. The rates of chemical reactions are major determinants of outcome in many histochemical techniques. Selective staining of different organelles within living cells is accomplished mainly with fluorochromes and is controlled by mechanisms different from those that apply to fixed tissues. Quantitative structure-activity relations (QSAR) of such reagents can be derived from such molecular properties as hydrophilic-hydrophobic balance, extent of conjugated bond systems, acid-base properties and ionic charge. The QSAR correlates with staining of endoplasmic reticulum, lysosomes, mitochondria, DNA, or the plasma membranes of living cells

Alcohol

SIGLEAvailable from British Library Document Supply Centre-DSC:97/08731 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The problem of proprietary dyes, with special reference to alamar blue, a proprietary dye revealed

No abstract available