Reasons for raising the maximum acceptable daily intake of EDTA and the benefits for iron fortification of foods for children 6-24 months of age.

The current maximum acceptable daily intake (ADI) of ethylenediaminetetraacetic acid (EDTA) of 1.9 mg day(-1) per kilogram bodyweight (mg day(-1)  kgbw(-1) ) limits the daily intake of iron as iron EDTA [ferric sodium EDTA; sodium iron(III) EDTA] to approximately 2-2.5 mg day(-1) for children 6-24 months of age.

Synthesis of riboguanosine pentaphosphate ppprGpp (Magic Spot II) via a phosphotriester approach.

The bifunctional phosphorylating reagent O,O-bis[1-benzotriazolyl]phosphoromorpholidate was used to introduce a 5'-O-triphosphate and a 3'-O-diphosphate function in a partially protected riboguanosine. Pilot studies indicated that protection of the 2'-OH of ribonucleosides with the acid-labile tetrahydropyranyl group, instead of the more labile 4-methoxytetrahydropyran-4-yl group, was most satisfactory for the preparation of the Magic Spot II.

Synthesis of short RNA fragments by the benzotriazolyl phosphotriester approach.

Analytical and experimental evidence will be presented to show that addition of a slight excess of 2-chlorophenyl-0,0-bis[1-benzotriazolyl]phosphate to a properly 2',5'-protected ribonucleoside gives an intermediate 3'-phosphotriester, which, after addition of a 2'-protected ribonucleoside, affords a dimer containing solely a 3'-5'-internucleotide linkage. The above phosphorylation procedure has been used in the synthesis of the pentamer UpApCpGpC.

Conformational analysis of the single-stranded ribonucleic acid A-A-C-C. A one-dimensional and two-dimensional proton NMR study at 500 MHz.

Proton NMR studies at 300 MHz and 500 MHz are reported on the ribotetranucleotide A-A-C-C. The complete 1H-NMR spectral assignment at 20 degrees C is given. Two-dimensional NMR was used to elucidate spin multiplets in 'crowded' regions.