Synthesis and biodistribution of 18F-labeled α-, β- and ω-fluorohexadecanoic acid

Yun-Sang Lee,Young Joo Kim,Gi Jeong Cheon,Jae Min Jeong 대한방사성의약품학회 2018 Journal of radiopharmaceuticals and molecular prob Vol.4 No.2

ω-[18F]-Fluorohexadecanoic acid (FHA) has been used for imaging of fatty acid metabolism of myocardium. To increase retention of radiolabeled fatty acid by blocking β-oxidation, methyl branched analogues have been used. In this experiment, we tried to synthesize 18F-labeled α-, β- and ω-FHA for imaging of the myocardial fatty acid metabolism. We synthesized α-, β- and ω-mesylated methyl hexadecanoates and labeled with 18F by reacting with [18F]TBAF in acetonitrile at 80ºC for 10 min. Methyl ester group was removed by 1 M NaOH at 80ºC for 5 min. The yields of α-[18F] and ω-[18F]FHA were 25.5 and 45.5%, respectively [EOS]. However, β-[18F] FHA was not labeled at all due to a fast elimination reaction. The biodistribution study in ICR-mice showed that ω-[18F]FHA has higher myocardial uptake and lower liver uptake than α-[18F]FHA. The electron-withdrawing effect of fluorine at α- position is believed to be the major factor affecting the biodistribution

Effects of hydrogen plasma treatment on SnO2:F substrates for amorphous Si thin film solar cells

Min-Seung Choi,Young-Ju Lee,Jung-Dae Kwon,Yongsoo Jeong,Ju-Yun Park,강용철,Pung Keun Song,Dong-Ho Kim 한국물리학회 2013 Current Applied Physics Vol.13 No.8

We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density.

Evaluation of 99mTc-MAG3-2-nitroimidazole for hypoxic tumor imaging

Yun Sang Lee,Young Joo Kim,Jae Min Jeong 대한방사성의약품학회 2019 Journal of radiopharmaceuticals and molecular prob Vol.5 No.1

2-Nitroimidazole derivatives have been reported to accumulate in hypoxic tissue. We prepared a novel 99mTc-MAG3-2-nitroimidazole and evaluated the feasibility for hypoxia imaging agent. Bz-MAG3-2-nitroimidazole wassynthesized by direct coupling of Bz-MAG3 and 2-nitroimidazole using dicyclohexylcarbodiimide. Bz-MAG3-2-nitroimidazole was labeled with 99mTc in the presence of tartaric acid and SnCl2-2H2O at 100°C for 30 min. And the reaction mixture was purified by C18 Sep-pak cartridge. The labeling efficiency and the radiochemicalpurity were checked by ITLC-SG/acetonitrile. The tumor was grown in balb/c mice for 8~13 days after thesubcutaneous injection of tumor cells, CT-26 (murine colon adenocarcinoma cell). Biodistribution study andtumor autoradiography were performed in the xenografted mice after i.v injection of 74 kBq/0.1 mL and 19MBq/0.1 mL of 99mTc-MAG3-2-nitroimidazole, respectively. In vivo images of 99mTc-MAG3-2-nitroimidazolein tumor bearing mice were obtained 1.5 hr post injection. The labeling efficiency was 45±20% and theradiochemical purity after purification was over 95%. Paper electrophoresis confirmed negative charge of99mTc-MAG3-2-nitroimidazole. 99mTc-MAG3-2-nitroimidazole was very stable at room temperature and its proteinbinding was 53%. The 99mTc-MAG3-2-nitroimidazole exhibited high uptake in the liver, stomach and intestine. In biodistribution study using tumor bearing mice, the uptakes (% ID/g) of the tumor were 0.5±0.1, 0.4±0.0,0.2±0.1 and 0.1±0.1 at 5, 15, 30 min and 4 hrs. Tumor/muscle ratio were 1.4±0.1, 2.2±0.83, 3.0±0.9, and 3.7(n=2) for 5, 15, 30 min and 4 hrs. The uptake in hypoxic area was found higher than in non-hypoxic area oftumor tissue by autoradiography. In vivo images showed the relatively faint uptake to the hypoxic tumor region. 99mTc-MAG3-2-nitroimidazole was successfully synthesized and found feasible for imaging hypoxia

Synthesis and biodistribution of ¹⁸F-labeled α-, β- and ω-fluorohexadecanoic acid

Lee, Yun-Sang,Kim, Young Joo,Cheon, Gi Jeong,Jeong, Jae Min Korean Society of Radiopharmaceuticals and Molecul 2018 Journal of radiopharmaceuticals and molecular prob Vol.4 No.2

${\omega}-[^{18}F]$-Fluorohexadecanoic acid (FHA) has been used for imaging of fatty acid metabolism of myocardium. To increase retention of radiolabeled fatty acid by blocking ${\beta}$-oxidation, methyl branched analogues have been used. In this experiment, we tried to synthesize 18F-labeled ${\alpha}-$, ${\beta}-$ and ${\omega}-FHA$ for imaging of the myocardial fatty acid metabolism. We synthesized ${\alpha}-$, ${\beta}-$ and ${\omega}$-mesylated methyl hexadecanoates and labeled with $^{18}F$ by reacting with $[^{18}F]$TBAF in acetonitrile at $80^{\circ}C$ for 10 min. Methyl ester group was removed by 1 M NaOH at $80^{\circ}C$ for 5 min. The yields of ${\alpha}-[^{18}F]$ and ${\omega}-[^{18}F]FHA$ were 25.5 and 45.5%, respectively [EOS]. However, ${\beta}-[^{18}F]FHA$ was not labeled at all due to a fast elimination reaction. The biodistribution study in ICR-mice showed that ${\omega}-[^{18}F]FHA$ has higher myocardial uptake and lower liver uptake than ${\alpha}-[^{18}F]FHA$. The electron-withdrawing effect of fluorine at ${\alpha}-$ position is believed to be the major factor affecting the biodistribution.

Evaluation of ^99mTc-MAG₃-2-nitroimidazole for hypoxic tumor imaging

Lee, Yun-Sang,Kim, Young Joo,Jeong, Jae Min Korean Society of Radiopharmaceuticals and Molecul 2019 Journal of radiopharmaceuticals and molecular prob Vol.5 No.1

2-Nitroimidazole derivatives have been reported to accumulate in hypoxic tissue. We prepared a novel $^{99m}Tc-MAG_3$-2-nitroimidazole and evaluated the feasibility for hypoxia imaging agent. $Bz-MAG_3$-2-nitroimidazole was synthesized by direct coupling of $Bz-MAG_3$ and 2-nitroimidazole using dicyclohexylcarbodiimide. $Bz-MAG_3$-2-nitroimidazole was labeled with $^{99m}Tc$ in the presence of tartaric acid and $SnCl_2-2H_2O$ at $100^{\circ}C$ for 30 min. And the reaction mixture was purified by $C_{18}$ Sep-pak cartridge. The labeling efficiency and the radiochemical purity were checked by ITLC-SG/acetonitrile. The tumor was grown in balb/c mice for 8~13 days after the subcutaneous injection of tumor cells, CT-26 (murine colon adenocarcinoma cell). Biodistribution study and tumor autoradiography were performed in the xenografted mice after i.v injection of 74 kBq/0.1 mL and 19 MBq/0.1 mL of $^{99m}Tc-MAG_3$-2-nitroimidazole, respectively. In vivo images of $^{99m}Tc-MAG_3$-2-nitroimidazole in tumor bearing mice were obtained 1.5 hr post injection. The labeling efficiency was $45{\pm}20%$ and the radiochemical purity after purification was over 95%. Paper electrophoresis confirmed negative charge of $^{99m}Tc-MAG_3$-2-nitroimidazole. $^{99m}Tc-MAG_3$-2-nitroimidazole was very stable at room temperature and its protein binding was 53%. The $^{99m}Tc-MAG_3$-2-nitroimidazole exhibited high uptake in the liver, stomach and intestine. In biodistribution study using tumor bearing mice, the uptakes (% ID/g) of the tumor were $0.5{\pm}0.1$, $0.4{\pm}0.0$, $0.2{\pm}0.1$ and $0.1{\pm}0.1$ at 5, 15, 30 min and 4 hrs. Tumor/muscle ratio were $1.4{\pm}0.1$, $2.2{\pm}0.83$, $3.0{\pm}0.9$, and 3.7 (n=2) for 5, 15, 30 min and 4 hrs. The uptake in hypoxic area was found higher than in non-hypoxic area of tumor tissue by autoradiography. In vivo images showed the relatively faint uptake to the hypoxic tumor region. $^{99m}Tc-MAG_3$-2-nitroimidazole was successfully synthesized and found feasible for imaging hypoxia.

A study of ^99mTc-sestamibi labeling condition using radio-chromatography

Moon, Sung-Hyun,Lee, Yun-Sang,Lee, Dong Soo,Chung, June-Key,Jeong, Jae Min Korean Society of Radiopharmaceuticals and Molecul 2017 Journal of radiopharmaceuticals and molecular prob Vol.3 No.1

Tc-99m labeled sestamibi ($^{99m}Tc$-MIBI) is one of most widely used radiopharmaceuticals for myocardial SPECT imaging. Radiolabeling of $^{99m}Tc$-MIBI is recommended by heating in $100^{\circ}C$ water bath for 15 min. However, the water bath might be a source of contamination. Thus, if radiolabeling of $^{99m}Tc$-sestamibi can be performed at room temperature, then it would be more convenient to use in clinical application. In this study, we performed the radiolabeling of $^{99m}Tc$-MIBI in different temperature conditions or using different instruments to find out the efficient labeling condition. We studied the $^{99m}Tc$-MIBI labeling at room temperature or $100^{\circ}C$ heating block, and checked the labelling yields every 1 min for 10 min using radio-TLC with 2 different eluents-saline and acetone. From the experiment, we confirmed that the $^{99m}Tc$-MIBI can be labeled over 90% yield but not completed at room temperature. However, the $^{99m}Tc$-MIBI labeling was completed when it was performed in the $100^{\circ}C$ heating block. Finally, we proved that heating is essential for complete $^{99m}Tc$-MIBI labelling, furthermore using heating block is also possible instead of water bath.

Purification and Characterization of Helicobacter pylori ${\gamma}$-Glutamyltranspeptidase

Song, Jae-Young,Choi, Yeo-Jeong,Kim, Jeong-Min,Kim, Yoo-Ree,Jo, Jin-Seong,Park, Jin-Sik,Park, Hee-Jin,Song, Yun-Gyu,Lee, Kon-Ho,Kang, Hyung-Lyun,Baik, Seung-Chul,Youn, Hee-Shang,Cho, Myung-Je,Rhee, Kw The Korean Society for Microbiology 2011 Journal of Bacteriology and Virology Vol.41 No.4

Gamma-glutamyltranspeptidase (GGT) was purified to electrophoretic homogeneity from the cell extract of H. pylori. The purified enzyme consisted of heavy and light subunits with molecular weights of 38 kDa and 21 kDa, respectively. N-terminal amino acid sequence of heavy and light subunits revealed that H. pylori GGT was processed into 3 parts for a signal peptide of 27 amino acid residues, a heavy subunit of 352 residues, and a light subunit of 188 residues during translation. The reaction rate for hydrolysis of ${\gamma}$-GpNA was 84.4 ${\mu}mol/min$ per milligram of protein, and that for the ${\gamma}$-glutamyl transfer from ${\gamma}$-GpNA to gly-gly was 23.8 ${\mu}mol/min$ per milligram of protein. The apparent Km values of H. pylori GGT for ${\gamma}$-glutamyl compounds were on the order of $10^{-3}$ to $10^{-4}$ M and those for acceptor peptides and amino acids were on the order of $10^{-1}$ to $10^{-2}$ M. The GGT protein kept approximately 80% of the initial enzymatic activity on incubation at $60^{\circ}C$ for 15 min. The optimum temperature and pH for reactions of both hydrolysis and transpeptidation were $40^{\circ}C$ and 9.0, respectively. The transpeptidation and hydrolysis reactions catalyzed by H. pylori GGT were strongly inhibited by L-Gln and moderately inhibited by L-Ala, L-Ser, ${\beta}$-chloro-L-Ala, and L-Glu. These results demonstrated that the biochemical properties of H. pylori GGT are different from those of other bacterial GGTs. Further, H. pylori GGT might degrade glutathione in the gastric mucous layer of humans if the enzyme could be secreted in the bacterial niches.

Biodistribution and PET imaging of [¹⁸F]FMISO in mousecolon cancer xenografted mice

Seelam, Sudhakara Reddy,Lee, Ji Youn,Kim, Young Joo,Lee, Yun-Sang,Jeong, Jae Min Korean Society of Radiopharmaceuticals and Molecul 2015 Journal of radiopharmaceuticals and molecular prob Vol.1 No.2

Hypoxia is an important adverse prognostic factor for tumor progression and is a major cause of failure of radiation therapy. In case of short-term hypoxia, the metabolism can recover to normal, but if hypoxia persists, it causes irreversible cell damage and finally leads to death. So a hypoxia marker would be very useful in oncology. In particular, 2-nitroimidazole can be reduced to form a reactive chemical species, which can bind irreversibly to cell components in the absence of sufficient oxygen, thus, the development of radiolabeled nitroimidazole derivatives for the imaging of hypoxia remains an active field of research to improve cancer therapy result. 2-nitroimidazole based hypoxia marker, [$^{18}F$]FMISO holds promise for the evaluation of tumor hypoxia by Positron emission tomography (PET), at both global and local levels. In the present study, [$^{18}F$]FMISO was synthesized using an automatic synthesis module with high radiochemical purity (>99%) in 60 min. Immunohistochemical analysis using pimonidazole confirmed the presence of hypoxia in xenografted CT-26 tumor tissue. A biodistribution study in CT-26 xenografted mice showed that the increased tumor-to-muscle ratio and tumor-to-blood ratios from 10 to 120 min post-injection. In the PET study, [$^{18}F$]FMISO also showed increased tumor-to-muscle ratios from 10 to 120 min post-injection. In conclusion, this study demonstrates the feasibility and utility of [$^{18}F$]FMISO for imaging hypoxiain mouse colon cancer model using small animal PET.

Loop와 HPLC Purification 방법보다 더 높은 비방사능을 보여주는 카트리지 Methylation과 Purification을 이용한 손쉬운 [ ¹¹C]PIB 합성

이용석,조용현,이홍재,이윤상,정재민,Lee, Yong-Seok,Cho, Yong-Hyun,Lee, Hong-Jae,Lee, Yun-Sang,Jeong, Jae Min 대한핵의학기술학회 2018 핵의학 기술 Vol.22 No.2

$[^{11}C]PIB$는 베타아밀로이드($A{\beta}\;plague$)라는 변성 단백질에 결합하여 뇌의 기능과 기억력을 서서히 감퇴시키는 비가역적인 질환인 치매를 조기에 감별할 수 있는 대표적인 방사성의약품이다. 지금까지 많은 실험실에서 $[^{11}C]PIB$는 자동화합성장치에서 $[^{11}C]methyl\;iodide$나 $[^{11}C]methyl\;triflate$를 만든 다음 loop나 vial 방법을 사용하여 methylation을 한 다음 HPLC로 정제를 하는 것이다. 하지만 기존의 보고된 방법은 시간이 오래 걸리며, HPLC와 같은 복잡한 시스템을 필요로 하여 소규모 실험실에서 합성하기에 적합하지 않으며, 최종 product에서 에탄올 함량이 높다는 단점이 있었다. 이러한 단점을 보완하기 위하여 카트리지만을 사용하여 카트리지에서 methylation과 purification을 동시에 실시함으로써 합성 시간을 단축하고, 비방사능이 높고, 낮은 에탄올 함량을 가진 $[^{11}C]PIB$를 합성 가능한지 확인하고자 하였다. 가장 널리 사용하는 카트리지 6종(CM, HLB, Alumina, C18, tC18, tC18 environmental을 선택하여 screening test를 실시하였다. 6-OH-BTA-0 1 mg을 c-HXO에 녹인 다음 6개의 카트리지에 loading를 한 다음 0.5 M MSP(pH 5.1) 20 mL로 정제를 한 다음 최종 fraction을 받아서 analytical HPLC로 전구체 잔류량을 측정한 결과 hydrophobicity가 낮은 계열(CM, HLB, Alumina)의 카트리지에서는 완충액으로 정제를 하였을 때 잔류전구체의 양이 많았으나, 탄소함량이 많은 계열의 카트리지(C18, tC18, tC18 environmental)에서는 잔류전구체의 양이 CM, HLB, Alumina 카트리지에 비하여 상대적으로 적었다. 완충액의 정제 농도와 부피를 최적화 하기 위하여 screening test에서 가장 좋은 결과를 나타낸 C18 series cartridge를 가지고 추가 실험을 진행하였다. 인산완충액 농도를 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 250 mM, 500 mM로 변화시켰으며, 에탄올 함량은 20%와 30%로 하여 용출액을 분석하여서, $[^{11}C]PIB$를 카트리지로 합성하기 위한 최적의 조합은 tC18 environmental cartridge와 0.5 M MSP 20 mL인 것을 알 수 있었다. 기존에 보고된 방법과 cartridge를 비교한 결과, 합성시간에서는 각각 15 ~ 18min, 8 ~ 9 min이 소요되었으며, product activity는 각각 $4.1{\pm}1.4\;GBq$ (n=41), $3.8{\pm}0.9\;GBq$ (n=3), 방사화학적 수율(based on HPLC analysis of the crude product)에서는 $13.9{\pm}4.4%$ (n=41), $12.3{\pm}2.2%$ (n=3)로 별다른 차이가 없었으며, 비방사능에 있어서는 HPLC purification method가 $78.7{\pm}39.7\;GBq/{\mu}mol$ (n=41), cartridge method가 $420.6{\pm}20.4\;GBq/{\mu}mol$ (n=3)로 카트리지 방법이 기존 방법보다 더 좋은 결과를 나타내었다. 또한, 잔류 용매(c-HXO)도 vial or loop method와 별다른 차이가 없었으며, 에탄올 함량에 있어서는 70%(기존 방법)에서 30%(카트리지 방법)로 두 배 이상 함량이 적다는 사실을 알 수 있었다. 지금까지 알아본바와 같이 cartridge method는 reported method(HPLC purification)에 비하여 더 향상된 결과를 보여준다는 사실을 확인하였다. $[^{11}C]PIB$ synthesis has been performed by a loop-methylation and HPLC purification in our lab. However, this method is time-consuming and requires complicated systems. Thus, we developed an on-cartridge method which simplified the synthetic procedure and reduced time greatly by removing HPLC purification step. We compared 6 different cartridges and evaluated the $[^{11}C]PIB$ production yields and specific activities. $[^{11}C]MeOTf$ was synthesized by using TRACERlab FXC Pro and was transferred into the cartridge by blowing with helium gas for 3 min. To remove byproducts and impurities, cartridges were washed out by 20 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ solution (pH 5.1) and 10 mL of distilled water. And then, $[^{11}C]PIB$ was eluted by 5 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ into the collecting vial containing 10 mL saline. Among the 6 cartridges, only tC18 environmental cartridge could remove impurities and byproducts from $[^{11}C]PIB$ completely and showed higher specific activity than traditional HPLC purification method. This method took only 8 ~ 9 min from methylation to formulation. For the tC18 environmental cartridge and conventional HPLC loop methods, the radiochemical yields were $12.3{\pm}2.2%$ and $13.9{\pm}4.4%$, respectively, and the molar activities were $420.6{\pm}20.4GBq/{\mu}mol$ (n=3) and $78.7{\pm}39.7GBq/{\mu}mol$ (n=41), respectively. We successfully developed a facile on-cartridge methylation method for $[^{11}C]PIB$ synthesis which enabled the procedure more simple and rapid, and showed higher molar radio-activity than HPLC purification method.

TNF-α 유전자형과 방광암과의 관계

정필두,김은정,엄민식,서정원,윤석중,김종석,이상철,김원재 충북대학교 의학연구소 2001 忠北醫大學術誌 Vol.11 No.2

연구목적: TNF-α는 일부 종양의 종양화 과정과 관련이 있는 것으로 알려져 있다. 본 연구는 TNF-α 발현에 영향을 미치는 TNF-α 촉진자 -308 부위의 유전적 다형성이 방광암과 관련이 있는지 유무를 알고자 시행하였다. 대상 및 방법: 유전자 분석을 위하여 환자 113명 및 대조군 109명으로부터 혈액을 채취하여 genomic DNA를 분리한 후 PCR-RFLP 및 direct DNA sequencing을 통하여 TNF-α유전자의 다형성을 조사하여 방광암의 발생, 병기 및 분화도와 비교 검토하였다. 결과: TNF-α 촉진자 -308 부위의 유전형은 대조군에서는 GG형이 83.5%(90례 및 GA형이 16.5%(19례)로 관찰되었으며 AA형은 없었다. 환자군에서는 GG 형이 85.4%(97례), GA형 및 AA형은 각각 13.1%(15례)및 0.8%(1례)에서 관찰되었다. 두 군 모두에서 GG형이 가장 많이 나타났으며 다음으로 GA형을 보이고 AA형은 1례의 방광암 환자에서만 관찰되었다. -308부위의 경우도 두 군 사이에 유전자형의 차이는 없었다(p=0.259) 분화도별 분포를 보면 grade I이 20례, grade II가 49례, grade Ⅲ은 34례였고 병기별로 표재성인 경우가 90례였으며 침윤성은 14례였다. 분화도가 나빠질수록 GA형이 증가하였다(p=0.04). 그러나 병기와 TNF-α promoter -308부위의 유전자형 사이에는 유의한 상관 관계가 없었다(p=0.123). 결론: 방광암 환자의 혈액에서 GA genotype이 관찰되는 경우, 분화도가 나쁠 가능성이 매우 높기 때문에 좀 더 적극적인 치료와 세밀한 추적관찰을 함으로써 방광암으로 인한 사망과 암의 진행을 예방할 수 있을 것으로 기대한다. Purpose : Tumor necrosis factor-alpha (TNF-α) is involved in tumorigenesis of several cancers as an endogenous tumor promoter. The purpose of this study was to investigate whether genetic polymorphism of TNF-α promoter region (-308) was associated with human bladder tumor. Materials and Methods: The DNA from 113 and 109 respective blood samples of bladder tumor Patients and control group was analyzed by PCR-based restriction fragment length polymorphism (RFLP) and direct DNA sequencing methods to characterize the genetic polymorphism of -308 promoter region of the TNF-α gene in bladder tumor patients. We compared the association of bladder tumor with genetic Polymorphism of TNF-α promoter region(-308) in relation to the stage, grade, recurrence and progressio. Results : Eighty-six percents(97/113) of bladder tumor patients and 83.5% (90/109) of control group showed genotype GG at -308 region of TNF-α. Difference in genetic variations of TNF-α promoter (-308) did not exist between bladder tumor patients and control group(p=0.259). Tumor grade was significantly related to the GA genotype (p=0.04). The higher is the grade in bladder tumor, the more frequent was the GA genotype. Tumor stage, recurrence and progression were not significantly associated with genetic polymorphism of TNF-α promoter region (-308). Conclusion: The GA genotype of TNF-a promoter region (-308) had a significant impact on TNF-α production and was related to higher grade tumor compared to GG genotype. TNF-α serum levels in bladder tumor patients were significantly higher than controls. These data suggested that TNF-α might involve the tumorigenesis of the bladder rather than treatment or prevention of bladder tumor.