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- Author or Editor: Xuebin Wang x
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Summary
The asymmetrical [99mTcN(PNP5)(NOEt)]+heterocomplex containing a terminal technetium-nitrogen multiple bond coordinated to the diphosphine ligand (PNP5) and the dithiocarbamate ligand (NOEt), was prepared through ligand exchange reaction. Its radiochemical purity was over 90% as measured by TLC and HPLC. Biodistribution in mice and SPECT imaging in dog were studied. The results showed that [99mTcN(PNP5)(NOEt)]+ possessed high myocardial uptake and good retention, and high target to non-target ratios, suggesting that it may be a potential myocardial perfusion imaging agent.
Abstract
In the present study, two novel 99mTc nitrido dithiocarbamate complexes containing heterocyclic linkage, the bis(N-2-(1-piperidyl)ethyl dithiocarbamato) nitrido technetium-99m complex 99mTcN(PPEDTC)2 and bis(N-2-(1-pyrrolidino)ethyl dithiocarbamato) nitrido technetium-99m complex 99mTcN(PREDTC)2 have been synthesized by the reduction of 99mTcO4 − into [99mTcN]2+ with stannous chloride in the presence of succinic dihydrazide and propylenediamine tetraacetic acid, followed by the addition of the corresponding dithiocarbamate ligands. The radiochemical purity of the complexes were over 90% as measured by thin layer chromatography (TLC). In vitro studies showed that the complexes possessed good stability. Their partition coefficients indicated that they were lipophilic complexes. Biodistribution in mice showed that the 99mTcN(PPEDTC)2 complex accumulated in brain with high uptake and good retention. As compared with the 99mTcN(PREDTC)2 complex, the former showed much higher brain uptake than the latter.
Abstract
Mixed ligand fac-tricarbonyl complex of [99mTc(CO)3-DMSA-MIBI] has been prepared starting from the precursor [99mTc(OH2)3(CO)3]+. The complex can be obtained in good yield and purity in a two-step procedure by first attaching meso-2,3-dimercaptosuccinic acid (DMSA, HOOCCH(SH)CH(SH)COOH) with [99mTc(OH2)3(CO)3]+, followed by addition of MIBI [tetrakis-2-methoxyisobutylisonitrile (CH3OC(CH3)2CH2-N≡C) copper(I) tetrafluoroborate] solution. The complex was characterized by TLC and HPLC and was studied by means of octanol-water partition coefficient, electrophoresis, stability in vitro, and normal mice experiment. Biodistribution in mice demonstrated that the complex showed higher myocardial uptake after 0.5-hour p.i. The ratios of heart/liver (%ID/g) in the case of 99mTc(CO)3-DMSA-MIBI was higher (1.88) than that observed in case of 99mTc-MIBI1 (0.93) after 0.5-hour p.i. (P<0.05). Results showed that the complex may be developed to a novel myocardial perfusion-imaging agent.
Abstract
The purpose of the investigation was to evaluate the feasibility of imaging inflammatory lesions with five small molecular weight complexes of 99mTc. The labeling yields of D-glucaric acid (D-Gca), citric acid (Cit), DL-malic acid (DL-Mal), L-malic acid (L-Mal) and tartaric acid (Tar) were all more than 90%. The percentage uptake/g tissue of them and 99mTc-pertechnetate (P) in mice with turpentine-induced abscesses and abscess/muscle (A/M), blood (A/B), liver (A/L), kidney (A/K) concentration ratios were calculated. The maximum A/M ratios were 4.02±0.21 (Cit, 3h), 4.30±0.77 (D-Gca, 3h), 4.04±0.21 (DL-Mal, 6h), 3.50±0.23 (L-Mal, 1h), 3.20±0.17 (Tar, 1h) and 3.23±0.41 (P, 1h) respectively. The scintigram was obtained in a rabbit with turpentine-induced abscess after 99mTc-D-Gca i.v. injection. Results demonstrated they all can accumulate in inflammatory lesions. Of them, 99mTc-D-Gca is probably a potential imaging agent on inflammatory lesions.
Abstract
The combustion kinetics of waste capsicum stalk (WCS) in Western China is investigated through thermogravimetric analysis compared with sawdust and coal, and co-combustion of WCS with coal is also investigated. Results show that the ignition characteristics of WCS is better than that of sawdust and coal, and the activation energy E of WCS-volatile combustion and WCS-char combustion are 78.55 kJ mol−1 and 44.59 kJ mol−1. However, integrating the characteristics of ignition and burnout, the combustion characteristic factor (S
N) of WCS is lower than that of sawdust. With the increasing in the heating rate, the ignition of WCS is delayed. Oxygen concentration 
affects E and k
0 of volatile combustion largely under rich-oxygen condition, when 
increases from 0.2 to 0.8, E has increased threefold and k
0 also intensively increases from 106 to 1013–1022. Oppositely, effect of 
on the E and k
0 of char combustion is little, and there is an exponential relationship 
between S
N and 
. For the tests of co-combustion, all the experimental and weighted-average curves coincide well, and there is no remarkable synergistic effect. With the increase of mixing ratio that WCS added, E and k
0 of volatile combustion increase, but correspondingly E and k
0 of char combustion decrease.
Abstract
The dimercaptosuccinic acid metronidazole ester (DMSAMe) was synthesized and radiolabeled with 99mTc to form the 99mTc-DMSAMe complex in high yield. The radiochemical purity of the 99mTc-DMSAMe complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The tumor cell experiment and the biodistribution in mice bearing S 180 tumor showed that the 99mTc-DMSAMe complex had a certain hypoxic selectivity and accumulated in the tumor with high uptake and good retention. The tumor/blood and tumor/muscle ratios increased with time, suggesting it would be a possible tumor hypoxia imaging agent.
