The Buccal Mucosa in Protein-calorie Deficiency in the Pig.

The buccal mucosa, chiefly human, in malnutrition, has been studied in recent years, but very little has been published on the microscopic appearances of the superficial epithelial cells in protein-calorie deficiency. It has been shown (Squires, 1958, 1961) that degenerative changes occur in the superficial mucosal cells of human patients suffering from apparent general malnutrition and that, if appropriate treatment is instituted, such changes are reversible. To summarize the findings briefly, if a scraping is taken from the healthy mucosa, the superficial cells, 20-80 pm in diameter with a conspicuous central oval nucleus 5-20 pm across, tend to desquamate in clumps or plaques; they are plump with welldefined edges, and stain well. The cells are comparatively resistant to mechanical injury, the proportion of broken or mutilated cells in the smear being 5-10%. Besides epithelial cells, in any one field several leucocytes are usually to be seen. In primary or secondary malnutrition, characteristic changes occur. The cells no longer tend to cling together, but are mainly separate, many lose their sharpness of outline and appear ‘moth-eaten’ and shrunken, the proportion of broken and mutilated cells is greatly increased, up to 70% of the number examined, the staining is poor, and there is a great increase in the number of leucocytes, both granular and non-granular. These appearances are so typical and easily observed that they have been employed with some success as a rough and cheap screening method for the mass detection of malnutrition amongst Bechuana schoolchildren (Squires, 1958, 1961) and also as evidence of recovery, but owing to the primitive conditions and lack of personnel no regular quantitative records taken over long periods could be obtained, nor could the question as to the nature of the nutrient deficiency responsible for the appearances be easily answered. It is the object of this paper to provide evidence that protein-calorie deficiency causes the changes in the superficial mucosal cells. (The question of increase in leucocytes is not examined here.) It has now been possible to examine buccal smears from piglets maintained under controlled conditions and fed at varying protein levels with and without added carbohydrate, as detailed by Friend, Heard, Platt, Stewart & Turner (1961). The effects upon the buccal mucosa of diets that would produce conditions resembling marasmus and, with the addition of carbohydrate, kwashiorkor in human infants could be studied quantitatively.