Effects of multivitamin supplementation for improvement of thiamin, riboflavin, and retinol nutrition in pediatric patients.

The effect of multivitamin supplementation on thiamin, riboflavin and retinol nutrition was studied in ten male chronic pediatric patients at Ramathibodi Hospital. MTV forte (Government Pharmaceutical Organization) was given 1 tablet daily for ten days and the effect was compared with the preceding ten-day control period. Anthropometric biochemical, clinical and dietary assessments were performed throughout the study. Biochemical assessments of vitamin nutrition at the beginning and the end of a 10-day non-supplementation period revealed multiple vitamin deficiencies in the subjects, though clinical manifestation was not seen. Hospital diets improved vitamin nutrition of some patients but most of them still showed subclinical vitamin deficiencies. Improvement of vitamin nutrition was clearly shown in most patients after MTV supplementation. Multiple vitamin supplements should be prescribed in high-risk patients since there was no definite pattern of vitamin deficiencies in various diseases and early detection of vitamin deficiency was difficult to perform. The dosage between 1-2 times of RDA was considered adequate in most of our patients.

Biochemical aspects of drug action and resistance in malaria parasites.

Biochemical aspects of action of antifolates and 4-aminoquinolines and their resistance in the malaria parasites are reviewed, with emphasis on pyrimethamine and chloroquine respectively. Resistance to pyrimethamine has been shown to be associated with either an increase in the amount of parasite dihydrofolate reductase or a reduced affinity of the enzyme for drug binding, in line with the presence of a distinctive pathway for folate metabolism. The theories for drug synergism in the folate pathway are discussed with respect to resistance to pyrimethamine and its combination with sulpha drugs. The biochemical basis for chloroquine resistance is still unclear, reflecting incomplete understanding of its mechanism of action. Data implicating the role of haemozoin and other components as a putative chloroquine receptor of the parasites are reviewed, and possible explanations for resistance are discussed.