Abstract
When neuroblastoma N 18 cells, precultured in vitamin B_1-and B_6-deficient Dulbecco's modified Eagle's minimum essential medium (MEM), were cultured in Eagle's MEM deficient in the same vitamin, cell proliferation was depressed to 75〜78% of that observed with the regular Dulbecco's and Eagle's media. Under the same culture conditions, the addition of thiamine+PL+CN-B_<12> or thiamine tetrahydrofurfuryl disulfide (TTFD)+PLP+OH-B_<12> to the deficient Eagle's MEM restored the impaired cell proliferation. The restorative effect of the latter three was more remarkable than the former three. Among the constituents of Vitaneurin^[○!R], TTFD returned the growth to 99% of that of the normal cells, whereas PLP or OH-B_<12> alone showed no appreciable improvement. On the other hand, the combined addition of these three vitamins showed a restoration of 106%, exceeding that of the cells growing in the regular media.
