Morphological investigations on the small intestinal mucosa of mouse after mild hyperthermic treatment.

Local hyperthermia, when applied as a therapeutic agent against radio-resistant tumours, can result in serious side effects in adjacent non-tumorous tissue, one especially thermo-sensitive organ being the small intestine. An experimental morphological study was therefore undertaken with mice to investigate whether "mild hyperthermia" (41 degrees C for 15, 30 and 60 min) causes alterations at the mucosa of the small intestine, and if so what are these effects and their likely pathomechanisms. Descriptive light and electron microscopical studies and morphometric evaluations are reported on the jejunal mucosa. The observed changes were most extensive after 60 min of 41 degrees C hyperthermia; but even 30 and 15 min hyperthermic treatment was followed by severe degenerative changes. The epithelium of the basal crypts and the stromal cells seemed to remain morphologically unaffected under these conditions, though the stroma can react with a temporary contraction. No "prime event" in the hyperthermia provoked tissue changes can be deducted from the combined light, electron microscopical, and morphometric studies. Comparing, however, the extent of the effects after mild hyperthermia of 60, 30 and 15 min, respectively, four phases of intestinal alterations due to mild hyperthermia and a likely pathomechanism of this treatment can be defined. The clinical implications of the findings are discussed.

Morphology and distribution of supraependymal cells in the third ventricle of the albino rat.

The supraependymal cells (SEC) are a normal component of the wall of the cerebral ventricles. In the hypothalamic area of the third ventricle they are restricted, in healthy animals, to the ependymal projection of the hypophyseotropic area. Here the SEC show great polymorphism. In addition to bipolar, multipolar and stellate or spider-like cells, transitional forms between these types can be seen. Their perikarya and processes can either remain at some distance from the ependyma or be in close contact with it. The processes may protrude between the ependymal cells or show surface differentiations that resemble the thin cytoplasmic folds of the mesenchymal wandering cells. Considering this and the variations in the number of cells, for example during the ovarian cycle, the SEC can be interpreted as mesenchymal cells, probably related to microglial cells of the subependymal layer. It is suggested that the SEC have a phagocytotic function and may be involved in the normal renewal of the ependyma. A definitive explanation for the restriction of the SEC to the hypophyseotropic area as well as the elucidation of their function remain to be found.