Charles F. Geschickter

Experimental control of serum calcium levels in vivo.

Summary The ability of ethylenediamine tetra-acetic acid to form undissociated calcium complexes at physiological pH has been utilized as a tool to regulate available serum calcium levels in vivo. Further evidence has been presented for the regulatory action of magnesium ion on serum calcium levels.

EPIDERMIDALIZATION OF THE CERVIX

In tissues that maintain themselves by continuous renewal, neither the embryonic pattern of the organ nor the nuclear chromatin determines the final pathway of differentiation, which is usually dependent upon chemical influences such as hormones and essential vitamins made available from sources external to the cells. In the early stages of differentiation all cells are pluripotential and this accounts for cartilaginous metaplasia in the callus of a fracture, for the appearance of macrophages and giant cells in foreign body reactions in the stroma, and for the variety of atypical patterns produced by excessive endocrine stimulation such as sweat gland epithelium in chronic cystic mastitis of the breast. This modern information makes it unnecessary to postulate special cells accumulated as embryonic rests to explain the process of epidermidalization in the endocervix that is reported in the present study. In this study, 100 cervices were examined from consecutive patients who had hysterectomies performed for noncervical diseases such as benign fibroids, metrorrhagia, and malignant tumors of the ovary. Sections were taken from 4 quadrants from the squamocolumnar junction. To this series were added cases obtained from autopsies in the young age groups with normal reproductive organs, and 13 cases were similarly studied in the newborn. The squamous metaplasia found was divided into the following groups: Group I, complete metaplasia-includes marked to moderate metaplasia of the endocervix extending to the glandular or endocervical lumen; Group 11, incomplete metaplasia-includes focal squamous metaplasia of the endocervix with persisting superficial columnar epithelium; and Group 111, senile or migratory metaplasia -includes changes in patients beyond the menopause. Reserve cell proliferation was excluded as a form of metaplasia in our series, although i t frequently accompanied metaplasia. Group I, complete metaplasia, was characterized by three to six layers of transitional or cuboidal cells with basophilic cytoplasm resembling that found in basal cells. The superficial layers only rarely matured in a fashion typical of the surface epithelium found in the normal portio vaginalis of the cervix. The metaplastic epithelium was predominantly immature but entirely replaced the columnar epithelium (FIGURE 1). There was usually a normal appearing basement membrane with an underlying mature but vascular stroma. In Group 11, incomplete or focal metaplasia, the transitional epithelium was found beneath persisting columnar epithelium, completely replacing it only in occasional foci. A complete basement membrane was usually lacking and the metaplastic cells appeared to be arising directly from the stroma, which was of the immature loose type (FIGURES 2a and b ) . In Group 111, senile metaplasia, the metaplastic epithelium was continuous and identical with the normal squamous epithelium for the ectocervix and seemed to be an extension of it. This finding was associated with an atrophic state of the endometrium and/or the ovaries (FIGURE 3 ) . The underlying