Using the dyes alcian blue and phloxine to study the distribution of the lining cells of the larynx.

What is it about?

The chemical reaction that occurs between alcian blue and mucin in the goblet cells in respiratory epithelium, and the ability of phloxine to penetrate layers of squamous cells provided a permanent demonstration of the lining cells of the larynx so that large numbers of specimens could be stored in fixative for examination and comparison without loss of colour. This technique demonstrated, at a glance, the normal distribution of lining cells in non-smokers as well as changes in the distribution of cells and the increase in areas of squamous cells (squamous metaplasia) in smokers and those with chronic disease. Also demonstrated was a mauve-staining intermediate epithelium. Paraffin sections of tissue was examined microscopically to confirm findings.

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Why is it important?

The ability to detect changes in the lining cells of the larynx (squamous metaplasia) is invaluable in the study of disease. This technique also revealed areas on intermediate epithelium about which little is known. On microscopic examination, the cells of this epithelium shared some of the features of squamous epithelium in that it was arranged in layers (stratified) and also with respiratory epithelium in that there were goblet cells present and cilia on the uppermost layer. This type of epithelium also bore a strong resemblance to the epithelium in the embryo. Further investigation of intermediate epithelium is warranted.

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