• The Korean Journal of Physiology
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• v.24 no.2
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• pp.345-352
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• 1990

To determine the role of sulfhydryl group in transport of organic ions across the basolateral membrane of renal proximal tubules, effect of p-chloromercuribenzoic acid (PCMB) on the transport of tetraethylammonium (TEA) and p-aminohippurate (PAH) was studied in rabbit renal cortical slices. PCMB caused irreversible inhibition of TEA and PAH uptake in a dose-dependent manner, with $I_{50}$ value (concentration for 50% inhibition) of $30\;{\mu}M$ for TEA and $75\;{\mu}M$ for PAH. Kinetic analysis of TEA and PAH uptakes showed that PCMB decreased Vmax $(62.35\;vs.\;28.32\;n\;mole/g{\cdot}min\;fur\;TEA:\;385.24\;vs.\;170.36\;n\;mole/g{\cdot}min\;for\;PAH)$ without changing Km. The inhibitory action of PCMB on TEA and PAH uptakes was independent of pH of the pretreatment medium. The inhibitory effect of PCMB on the uptake of TEA or PAH was prevented by dithiothreitol, but not by the substrate. PCMB inhibited Na-K-ATPase activity in a dose-dependent manner with $I_{50}$ value of $50\;{\mu}M$, which is similar to those for TEA and PAH uptake. These results suggest that PCMB inhibits the transport of organic cations and anions in the renal basolateral membrane by directly affecting the SH-group in the transporter molecules or secondly by altering the Na-K-ATPase activity.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.298-304
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• 1998

Purpose: We evaluated the usefulness of Re-188 sulfur colloid for radiation synovectomy and therapy of intraperitoneal metastasis. Materials and Methods: We investigated the labeling efficiency of Re-188 sulfur colloid on various conditions. The stability of Re-188 sulfur colloid was observed at room temperature for 24 h and in human serum and synovial fluid for 72 h. The particle size distribution of Re-188 sulfur colloid was measured by filtering with various pore size filters. Animal experiment was performed in mice and rabbits. Results: The labeling efficiency of Re-188 sulfur colloid was $64.5{\pm}5.8%$ (n=5) at the conditions of sodium thiosulfate 40 mg, EDTA $Na_2.2H_2O$ 0.8 mg, $KReO_4$ 0.8 mg at pH 1. After purification, the radiochemical purity was higher than 99%. The stability of Re-188 sulfur colloid was high (>99%) at room temperature for 24 h and in human serum and synovial fluid for 72 h. The particle size distribution of Re-188 sulfur colloid was 0.3% ($<1{\mu}m$), 11.2% ($1{\sim}5{\mu}m$), 25.8% ($5{\sim}10{\mu}m$) and 52.8% ($>10{\mu}m$). In mice, 1 h postinjection of Re-188 sulfur colloid into tail vein, uptakes in lung, liver and muscle were $37.30{\pm}5.36$, $32.33{\pm}1.79$, $6.60{\pm}0.02%$ ID/organ respectively. After i.p. injection in mice, the uptakes of extraperitonial organs of Re-188 sulfur colloid at 1 and 24 h were $0.1{\pm}0.1$, $0.4{\pm}0.1%$ ID/organ, and the excretions through urine and feces (${\sim}70 h$) were low ($2.68{\pm}0.80$, $0.95{\pm}0.17%$). When Re-188 sulfur colloid was injected to synovial space of rabbit, the uptake in other organs except knee was very low. Conclusion: Re-188 sulfur colloid showed high labeling efficiency, stability and potency for clinical use.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.105-109
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• 1995

L-3-[$^{123}I$]iodo-${\alpha}$-methyltyrosine([$^{123}I$] IMT) was synthesized by electrophilic radio-iodination using chloramine-T and Iodobead in phosphate buffered solution. And the biodistribution was examined in 9L glioma bearing rats. The radiosynthesis of [$^{123}I$]IMT with iodobead was simpler and higher in radiochemical yield(88%) than the method using chloramine-T(83%) as radioiodinating reagent. The highest yield was obtained from the reaction using 1 piece of Iodobead, $200{\mu}g$ ${\alpha}$-methyltyrosine in $100{\mu}l$ phosphate-buffered solution(pH 5.5) and the reaction was completed in 7min. 24 hours after the injection, the biodistribution in 9L glioma transplanted rats revealed the in vivo deiodination, the excretion via kidney, and 3 times higher uptake in the tumor than normal brain. These results suggest the promising clinical use of [$^{123}I$] IMT in the various malignancies.