PLASMODIUM-FALCIPARUM AND PLASMODIUM-BERGHEI - EFFECT OF MAGNESIUM ONTHE DEVELOPMENT OF PARASITEMIA

The in vitro growth of Plasmodium falciparum was reduced by 35 and 43% through high concentrations (5 mmole/liter) of magnesium in RPMI medi um and magnesium-free medium, respectively, after 48 hr whereas no sig nificant inhibition could be observed under these conditions after 24 hr cultivation in the respective medium. Levels of magnesium between 0 .5 and 3 mmole/liter showed no inhibitory effect on the in vitro growt h of P. falciparum even after long-term exposure for 7 days. The 50 an d 90% chloroquine inhibitory concentrations of the chloroquine-resista nt strain KI after 24 hr were reduced to some extent in the presence o f magnesium at 5 mmole/liter, but less than in the presence of verapam il at 10 mu mole/liter, which showed intrinsic activities at this conc entration and which completely reversed resistance. However, high phys iologic magnesium plasma levels were associated with a significantly l onger survival time of NMRI mice infected with P. berghei strain ANKA, compared to normal physiological plasma magnesium levels. It is concl uded that in the case of clinically symptomatic magnesium deficiency, supplementation of magnesium will not aggravate concomitant plasmodial infections and therefore should not be withheld. (C) 1995 Academic Pr ess, Inc.