Development Of Mammary Tissue Research Articles

The Relationship of Mammary Development and Body Weight

Summary Nineteen calves of the Holstein and Guernsey breeds were used to determine the relationship of mammary development to body wight. A highly significant statistical relationship was found to exist between the development of the mammary secretive tissue and body weight of both the Holstein and Guernsey heifer calves at 3 months of age. Highly significant correlations also were found between mammary tissue development and gains in body weight from 8 days to 3 months of age of the heifer calves of both breeds. The lengths of the secretive tissues of Guernsey calves were related significantly to body weight at 6 months of age; however, there was no correlation in this respect with the Holstein calves at this age. There was no significant correlation between the width of the mammary secretive tissue and body weight of either breed at 6 months of age. No significant correlation was found between the gains in body weight from 8 days to 6 months and mammary development of either breed.

A Comparative Study of the Life History of the Female Mammary Gland in Two Strains of Albino Mice

In searching the literature nothing could be found concerning the life history of the mammary gland in mice, although much work has been done on other rodents. Since the mouse is used so extensively in cancer research as an experimental animal, and since cancer of the mammary gland is a well recognized entity in certain strains of mice, it was thought that it would be interesting to make a comparative study. To do this, two strains of mice were necessary, one showing a low incidence of mammary cancer in the females, and the other showing a high incidence. The material presented here represents an attempt to work out the development and distribution of mammary tissue in two such strains of mice. The study is a preliminary one, and the material is limited, but it was decided that should the two strains exhibit any remarkable differences, a more extensive survey might prove both interesting and profitable. The high tumor incident strain has been designated throughout as SPTM, and the low tumor incident strain as Loomis 1. Bagg strain was abandoned because of lack of material. Data concerning the animals used in this study are found preceding the plan of work. Purpose. By gross and microscopic study (1) to trace the development and distribution of mammary tissue in female mice; (2) to compare two strains: (a) one having a low mammary carcinoma incidence (no strain that has been studied earefully has been known to be tumor free) and (b) a high spontaneous mammary tumor strain; (3) to find, if possible, when deviations from the normal begin to occur, and to trace these deviations to the developed neoplasm.