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Biomedical subjects

T Odori

Publications and source records attributed to T Odori.

At least 37 records · Page 2Linked to original sources

Superimposition of Krypton-81m single photon emission CT and X-ray CT images for cerebral blood flow evaluation.

Selective arteriographic infusion of krypton-81m was used to obtain cerebral single photon emission computed tomograms. These were then superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. This method enhances the detecting capability for abnormal perfusion areas and has been used in 21 patients with various brain diseases.

Carotid Artery Thrombosis↗

[Detection of cancer by radionuclide imaging].

Tumor imaging by radiopharmaceuticals classified into two modalities; The one is a negative imaging, whereby a tumor is depicted as a non-functional cold spot. The other is a positive imaging on the use of tumor seeking agents. The detectability of the tumor as a cold spot has enhanced by introducing the emission computed tomography. A variety of effort to develop specific tumor seeking agents are in progress, by radio-labeling tumor specific antigen and its abnormal metabolic conditions using cyclotron produced radioactive metabolites as well as radiometal compounds.

Humans↗

Analysis of 99mTc-pyridoxylidene-glutamate complex formation and its preparation with tin-adsorbed-resin: Sn-Resin kit method.

99mTc-Pyridoxylidene-glutamate (Tc-PG) was introduced in 1975 by Baker et al. as a cholescintigraphic agent. Nevertheless its routine use has been limited due to the autoclaving process involved. To shorten the labeling procedure, an analysis of Tc-PG complex formation using the stannous chloride method was carried out. Sn-Resin (stannous ion adsorbed onto cation exchange resin) was used for labeling a stable Tc-PG with high efficiency. A preautoclaved complex of pyridoxal and glutamate was required but the labeling procedure took only 10-15 min after the elution of 99m-TcO4- from the generator. Formation of a complex other than a 99mTc-complex of the Schiff -base ligand pyridoxylidene-glutamate is discussed. The new formulation of a Tc-PG kit (Sn-Resin) simplified the labeling method and reproducible data to that already reported by Baker was obtained in chromatographic studies. Its suitability in hospital departments has already been shown in clinical studies.

Bile↗

Technetium coordination state as a factor of stability in 99mTc-complexes used in hepatobiliary system: comparative studies on 99mTc-complexes of pyridoxal with glutamate (Tc-PG) and isoleucine (Tc-PI).

Studies on 99mTc-Penicillamine (Tc-Pen) have given us some insight into the significance of the technetium coordination state in hepatobiliary clearance behavior. A 99mTc-complex of pyridoxal and glutamate (Tc-PG) prepared by Baker et al. (1975) using an autoclaving process or by a Sn-Resin kit method (Horiuchi 1981) was compared with a 99mTc-complex of pyridoxal and isoleucine (Tc-PI) prepared by the method of Kato and Hazue (1978) through an intermediate compound of stannous ion, at room temperature. Tc-PG and TcPI complexes analyzed by thin layer chromatography, sephadex column chromatography (G-15), octanol extraction, and ligand exchange reaction showed different chemical properties. Their biological evaluation also demonstrated great differences in biodistribution in mice, metabolic studies, protein binding, and rat bile excretion. Tc-PG was estimated as an hepatobiliary agent with strong metal-ligand binding, inert to ligand exchange reaction with Pen at physiological pH; the likely occurrence of technetium in a mononuclear or dinuclear state providing the great stability observed in its biological and in vivo behavior was compared with the relatively weaker binding observed in Tc-PI, a highly lipophilic complex of high liver partition but of low stability, denoting its different chemical characteristics. The technetium coordination state in radiopharmaceuticals is responsible for the integrity of the molecule while in the blood pool and its relevance in impaired liver uptake is discussed.

Animals↗

[99mTc-2-mercaptopropionylglycine: different biliary excretion behavior in different animal species (author's transl)].

Labeling of 2-mercaptopropionylglycine (2-MPG) with 99mTc, was studied and its chemical characteristics were examined. Further, biliary excretion behavior of this complex was comparatively estimated in mice, rats, and rabbits. 99mTc-2-MPG was rapidly excreted in large quantities into the bile in mice and rats: within 1 hr after injection, 51% of the injected dose was recovered from the bile in rats. On the other hand, the ligand exchange reaction between this complex and penicillamine indicates that a low hydrolyzed 99mTc species is coordinated with 2-MPG. These results suggest that a low hydrolyzed 99mTc is an effective feature in biliary excretion behavior of 99mTc compounds. Another interesting in vivo behavior of 99mTc-2-MPG is the difference observed in mice and rabbits: in mice, very high 99mTc activity is concentrated in the gallbladder and the clearance from tissues other than the gallbladder is rapid, whereas in rabbits, although a rapid and high excretion into the gallbladder is observed, a considerable high 99mTc activity is retained in the liver and the kidney. One reasons for this different in vivo behavior is the low stability of this complex at high dilution: a big animal has the large dilution volume which lead to higher decomposition estimated by the higher liver and kidney retention or the lower bile excretion. In conclusion, studies carried on 99mTc-2-MPG showed a good biliary excretion behavior but an in vivo unstableness in big animals.

Amino Acids, Sulfur↗

[Evaluation of 99mTc-HIDA complex as a cholescintigraphic agent (author's transl)].

In the reaction labeling N-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (HIDA) with 99mTc, several complexes with different chemical characteristics were observed to occur with slight changes in the labeling conditions. Among these complexes, a complex detected in the bile of rats was limited to one complex, named as complex II. The preparation method of 99mTc-HIDA complex II and the exchange reaction between this complex and penicillamine indicate that 99mTc is coordinated with HIDA as low-hydrolyzed 99mTc in this complex. This complex is excreted rapidly through the bile and within 1 hr, about 65% of the total activity injected is recovered from bile in rats. The organ distribution of this complex was studied in mice by radioassay and in rabbits by scintillation camera and, in both cases, the radioactivity was accumulated in the gallbladder. These results suggest that the 99mTc chemical state, low-hydrolyzed state, relates to the bile excretion behavior of this complex, a potentially useful cholescintigraphic agent.

Acetanilides↗