We have constructed three mutants in the thioredoxin (trxA) gene changing its catalytic core between Cys-32 and Cys-35. Oligonucleotide-directed mutagenesis was carried out to replace conservative Gly-33 or Pro-34 by leucine, lysine, glutamine, phenylalanine or tryptophane. The mutants were characte
Evaluation of the influence of the aqueous phase bioconstituent environment on the F-19 T1 of perfluorocarbon blood substitute emulsions
✍ Scribed by Stephen R. Thomas; Ronald G. Pratt; Ronald W. Millard; R. C. Samaratunga; Yoseph Shiferaw; Leland C. Clark Jr; Richard E. Hoffmann
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 489 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Oxygen‐sensitive F‐19 magnetic resonance imaging of perfluorocarbon compounds requires that fluorocarbon T1 changes correlate with the local Po~2~ and not with the composition of the surrounding aqueous phase. The influence of various bioconstituents and paramagnetic ions within the aqueous phase on the F‐19 fluorocarbon phase T1 for PFC emulsions was evaluated at 0.14 and 0.66 T. T1 was measured for FC‐43, perflubron, and a fluorinated surfactant. Controlled variables introduced in the aqueous phase included annex solution constituents, blood, pH changes, and Gd‐DTPA. For a constant Po~2~, the F‐19 T1s were independent of the emulsion constituents, blood concentration, and pH. For FC‐43 and perflubron, F‐19 T1 was independent of the Gd‐DTPA concentration, while the aqueous phase T1 decreased by more than an order of magnitude. XMO‐10 (smallest emulsion particle size) showed a slight decrease in F‐19 T1 with increasing Gd‐DTPA concentration at 0.66 T.
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