Effect of bacterial monoassociation on brush-border enzyme activities in ex-germ-free piglets: comparison of commensal and pathogenic Escherichia coli strains.

This study was designed to investigate the effect of monoassociation of germ-free piglets with Escherichia coli strains on the development of intestinal brush-border enzyme activities. Piglets were delivered by hysterectomy, reared for seven days under germ-free conditions and fed milk formula diet. One group was maintained germ-free, the other four groups were monoassociated on day eight with one of four E.

The effect of bromide on the ultrastructure of rat thyrocytes.

Electron microscopic examination of thyroid tissue following administration of bromide to rats showed marked hypertrophy and hyperplasia in the thyrocytes, microfollicular rearrangement and lowered volume of colloid. The luminal surface of the thyrocytes showed increased size and number of microvilli, often filling the microlumen. Most of the nuclei were irregular in shape with unusual incisions and a higher density of chromatin.