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Biomedical subjects

D Eshima

Publications and source records attributed to D Eshima.

40 records · Page 3Linked to original sources
PubMed1986

Synthesis and biological evaluation of technetium-99m MAG3 as a hippuran replacement.

A new technetium-chelating agent based on a triamide monomercaptide tetradentate set of donor groups, mercaptoacetylglycylglycylglycine (MAG3), was synthesized and evaluated. Chelation with 99mTc resulted in a single radiochemical product as expected. Studies in mice of [99mTc]MAG3 indicated excretion rates faster than omicron-iodohippurate (OIH) both in normal and in probenecid treated animals. Specificity for renal excretion was essentially complete. Clearance studies in rats resulted in 2.84 ml/min/100 g for [99mTc]MAG3, 2.17 for OIH, and 1.29 for [125I]iothalamate. Extraction efficiencies were 85% for [99mTc]MAG3, 69% for OIH and 39% for [125I]iothalamate. Probenicid depressed the clearance both of [99mTc]MAG3 and OIH at 25 and 50 mg/kg/hr, but to a greater extent with [99mTc]MAG3. The greater effect is offset, however, by the larger fraction secreted by the renal tubular cells. The animal results suggest that [99mTc]MAG3 may be a useful alternative to [131I]OIH.

Animals↗
PubMed1986

Comparison of iodine-131 OIH and technetium-99m MAG3 renal imaging in volunteers.

Animal studies have suggested that the nonisomeric N3S triamide mercaptide ligand, 99mTc mercaptoacetyltriglycine (MAG3), may provide a satisfactory 99mTc-labeled replacement for 131I hippurate (OIH). Sequential 30-min [99mTc]MAG3 (5-10 mCi) and [131I]OIH (300 microCi) imaging studies were performed in ten normal volunteers in order to compare the image quality, renal excretion, blood clearance, and time to peak height of the renogram curve. In addition, [99mTc] MAG3 (5 mCi) and [131I]OIH (150 microCi) were administered simultaneously in eight volunteers for comparison of 180-min blood and plasma clearances and urine excretion. In the sequential imaging studies, the blood clearance of [99mTc]MAG3 was more rapid than [131I]OIH with a mean clearance of 1.30 l/min compared with 0.88 l/min for [131I]OIH (p less than 0.05). Seventy-three percent of the injected dose of the MAG3 was excreted by 30 min compared with 66.8% for [131I]OIH. Whole kidney and cortical renogram curves showed no significant difference in the time to peak height for MAG3 and [131I]OIH. In all subjects, the quality of the [99mTc]MAG3 images were clearly superior to [131I]OIH. Following simultaneous injection, blood and plasma clearances for [131I]OIH were more rapid than MAG3 when determined for multiple time intervals from 0-30 to 0-180 min (p less than or equal to 0.05). The 0-30-min clearances of MAG3 and [131I]OIH were only slightly greater than the 0-180-min clearances and can be used to obtain valid comparisons of the two agents. As in the sequential study, 30-min urine excretion was greater for MAG3 than [131I]OIH (73.1 compared with 69.6%) but the difference was not statistically significant. Although the differences in the MAG3 clearances following sequential and simultaneous administration are not satisfactorily explained, the fact that both clearances were rapid, the MAG3 and OIH renogram curves were quite similar, and 30-min urine excretions of MAG3 and OIH were essentially identical suggests that MAG3 may become a 99mTc replacement for [13I]OIH and further clinical evaluation is warranted.

Blood Proteins↗
PubMed1984

Comparison of 99mTc-N-pyridoxyl-5-methyltryptophan and 99mTc-N-(3-bromo-2,4,6-trimethylacetanilide)-iminodiace tate as hepatobiliary radiopharmaceuticals in rats.

99mTc-N-(3-bromo-2,4,6-trimethylacetanilide)iminodiacetat e (I) and 99mTc-N-pyridoxyl-5-methyl-tryptophan (II) have been described as having optimal properties as hepatobiliary radiopharmaceuticals. This study compared specificity for hepatobiliary excretion, blood disappearance, rates of biliary appearance, and pharmacokinetic parameters including hepatic clearance, volumes of distribution, and mean residence times in normal and sulfobromophthalein-treated rats. The specificity of I was higher as indicated by 94% in the bile at 90 min compared to 91% for II in normal rats and a urine excretion of 0.3% for I compared with 1.9% for II. In sulfobromophthalein-treated animals, urine excretion increases were only to 0.5 and 3.0% for I and II, respectively. In control rats, blood disappearance was similar for both I and II, but II disappeared faster in treated animals. The clearance of II was 70 mL/min/kg in normal and 47 mL/min/kg in treated rats; clearance of I was 51 and 30 mL/min/kg in normal and treated rats, respectively. Volumes of distribution were larger for II. Compound I was superior in specificity while II was superior in clearance and excretion kinetics.

Aniline Compounds↗