Localization of lipofuscin in the duodenums of vitamin E-deficient rats.

In human malabsorption syndromes, lipofuscin accumulation has been reported to occur exclusively within the muscle layers of the intestine. It has been widely speculated that this lipofuscin deposition is related to vitamin E deficiency. To determine whether vitamin E deficiency leads to the same pattern of intestinal lipofuscin accumulation as that seen in many human malabsorption syndromes, the duodenums of rats that had been fed a vitamin E-deficient diet for 17 or 34 wk were examined for the presence of lipofuscin. Lipofuscin did not appear in the muscle layers of the duodenum until 34 wk, at which time occasional fibers containing large amounts of lipofuscin were present. An earlier and more pronounced deposition of lipofuscin occurred within connective tissue cells of the intestinal villi. After 17 wk, many fibroblastlike cells in the lamina propria of the villi contained large amounts of lipofuscin. By 34 wk, the numbers of these lipofuscin-containing cells in the lamina propria had increased substantially, and scattered cells containing lipofuscin were also seen in the submucosa. The difference in intestinal lipofuscin distribution between vitamin E-deficient rats and humans with malabsorption syndromes suggests that other factors, in addition to vitamin E, probably play important roles in regulating lipofuscin accumulation in the intestine.

Lipofuscin accumulation resulting from senescence and vitamin E deficiency: spectral properties and tissue distribution.

The corrected fluorescence emission spectra and tissue distributions of the autofluorescent pigments which accumulate during normal aging and as a consequence of vitamin E deficiency were studied in albino rats. In the retinal pigment epithelium, both the age-related pigment (lipofuscin) and the pigment related to vitamin E deficiency had essentially identical emission spectra. Peak emission occurred from 590 to 650 nm. Young animals which had been kept on a vitamin E deficient diet for 17 weeks after weaning showed significant accumulations of autofluorescent pigment in uterus, duodenum, and retinal pigment epithelium, but not in the spinal cord or inferior olivary nucleus of the brain. Old animals (96 weeks) fed a commercial diet with adequate vitamin E had accumulated lipofuscin in the retinal pigment epithelium, spinal cord gray matter, and inferior olivary nucleus, but not in the duodenum or uterus. Thus, while the auto-fluorescent pigments related to aging and vitamin E deficiency have similar properties, their tissue distributions are quite different.

Simultaneous gelatin embedding of multiple areas of the arterial tree.

An embedding method for simultaneously cutting frozen sections of multiple segments of the arterial tree is presented. The segments are stacked in a standardized form and embedded in gelatin. Preparation of the blocks, cutting on a freezing microtome and storage of remnants are discussed. Alignment of the segments was easily achieved and the blocks were sectioned without difficulty. This technique saves space and effort and facilitates screening and rapid reading of slides.