Lithium has previously been observed to stimulate in vitro Dexter culture hemopoiesis with increases in granulocytes, megakaryocytes, and pluripotent stem cells (CFU-S). In the present study, a two-phase murine Dexter culture system was established to study the mechanism of lithium-mediated stem cell stimulation. Different lots of horse sera or fetal calf sera were found to have markedly different effects on Dexter culture growth; given the appropriate sera supplementation, supernatant cells from Dexter cultures established from C57BL/6J mice 3 wk previously were free of stromal-forming capacity, but had stem cells and could grow on 900–950 R irradiated stroma. Conversely, in vitro irradiation (900–950 R) of 3-wk cultures resulted in a stem-cell-free adherent monolayer that could support growth for up to 9 wk in culture. The stroma from Dexter cultures preexposed to lithium chloride (1.0 mmole/liter) for 3 wk, irradiated (900 R), and then refed with 3-wk Dexter supernatant cells has an enhanced capacity to support cell production, CFU-S, and probably granulocyte-macrophage colony-forming cell (GM-CFU-C) production, as compared to stroma not preexposed to lithium. Lithium carryover was ruled out in these experiments. These data indicate that lithium stimulates CFU-S and in vitro granulopoiesis by an indirect effect on a radioresistant adherent stromal cell.
\s=b\ Erythrocyte polyamine levels were measured in the blood from 29 untreated patients whose conditions were diagnosed as head and neck cancer. Only nine (31%) of these patients had elevations of erythrocyte spermidine and/or spermine levels above the reference ranges determined for normal persons.However, a positive correlation was observed between the erythrocyte spermidine levels and the clinical tumor stage. Serial erythrocyte polyamine determinations were performed on the blood from 12 of these patients before and after either surgical or radiation therapy. In 11 of the cases, the erythrocyte spermidine levels decreased after tumor therapy regardless of whether there was prior elevation above the reference range. The erythrocyte spermine levels in these patients were more variable in their response to tumor treatment. Therefore, although erythrocyte polyamine levels were only slightly to moderately elevated in response to the small tumors characteristic of the head and neck, the measurement of erythrocyte spermidine, potentially, may offer a simple and effective means of monitoring the course of therapy used in patients with head and neck cancer. (Arch Otolaryngol 1981;107:752-754) The naturally occurring aliphatic polyamines, putrescine, spermi¬ dine, and spermine, are found in all types of cells.12 Although their exact physiologic function is unknown, it has been shown that they play neces¬ sary roles in cell growth and that their rate of accumulation parallels the rate of cellular proliferation.3 4 The struc¬ tures of these compounds are as fol¬ lows:Evidence has accumulated during the past ten years that suggests that polyamines are of potential value as
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