Twenty-eight-day oral toxicity study of lycopene from recombinant Escherichia coli in rats.

Lycopene produced by recombinant Escherichia coli was tested for subacute oral toxicity to determine its No-Observed-Adverse-Effect Level (NOAEL). Doses of 0, 200, 500 and 2000 mg/kg body weight/day were administered daily by gavage to 10 rats/sex/group for 28 days. No statistically significant, dose-related effect on body weight gain, clinical signs or ophthalmoscopic parameters was observed in any treatment group.

Recovery of injured adrenal medulla by differentiation of pre-existing undifferentiated chromaffin cells.

We described previous that the adrenal medulla recovers rapidly from the injuries due to salinomycin. In the present study we found the recovery to be apparently due to differentiation of pre-existing, primitive undifferentiated, chromaffin cells, rather than mitosis, as evidenced by lack of incorporation of 5-bromo-2-deoxyuridine in the differentiating and/or differentiated chromaffin cells. Electron-dense, striated fibrils observed within the necrotic cells and in the extracellular space were presumed to be intermediate degradation products.

Prompt recovery of damaged adrenal medullae induced by salinomycin.

The morphologic changes in the adrenal medullae of rats treated with an ionophore antibiotic, salinomycin, are described. Male rats of approximately 7 wk of age were treated orally with a single dose of salinomycin at 80 mg/kg body weight. Following this treatment, the adrenal glands were examined, using immunohistochemistry, for neurofilament, laminin, fibronectin, and S-100 protein; the glands were also examined using transmission electron microscopy.

A new type of cell death, the protruded type, observed in the adrenal gland of normal rats.

Apart from apoptosis, a type of parenchymal cell death by the cell protruding into the capillary lumen was observed in the adrenal gland of normal Sprague-Dawley rats. Ultrathin sections were prepared in the conventional manner and were examined by electron microscopy. The protruded cells (p-cells) had the electron lucent cytoplasm and the p-cells with ruptured cell membranes were observed in the capillaries.