• 대한방사성의약품학회지
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• 제3권2호
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• pp.72-79
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• 2017

Arbutin is a hydroquinone derivative with a glucose moiety. As a tyrosinase inhibitor, it is widely used as a skin-whitening cosmetic agent for the treatment of cutaneous hyperpigmentary disorders, such as melasma and freckles. In the medical field, many studies have addressed the use of arbutin in various tumors, but the mechanism for tumor uptake of arbutin is still unclear. In this paper, we radiolabeled arbutin using radioiodine and studied its pharmacokinetics and tumor uptake via biodistribution experiments and single-photon emission computed tomography (SPECT) imaging. Radiolabeled $^{131}I-arbutin$ was stable for up to 24 h in PBS and serum. Biodistribution studies and SPECT imaging indicated high uptake of the compound in the bladder and kidneys shortly after injection. Twenty-four hours post-injection, significant deiodination was observed. Apart from high thyroid uptake, selective tumor uptake was clearly observed. The tumor-to-muscle and tumor-to-blood ratios were 26 and 9, respectively.

• Nuclear Engineering and Technology
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• 제12권2호
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• pp.81-87
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• 1980

락토퍼옥시데이즈(lactoperoxidase, LPO)를 사용하여 인슈린을 $^{125}$/I로 표지반응 시켰다. 반응생성물은 전분젤 전기영동(SGE) 과 세파덱스 젤여과(SF) 둥 두단계를 거쳐 정제하였다. 표지수율 과표지생성물의 항체에 대한 결합능으로 보아 종래의 클로라민-T법 (표지수율 약 35%)보다 효소법 (표지수율 약 50%)이 우수하였다. 인슈린의 첨가없이 LPO법으로 표지반응을 진행시킨 다음 SGE, 종이 크로마토그래피, 방사선사진술 등을 적용하여 LPO법에서의 부산물을 확인할 수 있었다. SGE와 SF에서의 분리 분별 부분에 관해서도 분석, 토의하였다.

• 대한방사성의약품학회지
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• 제4권1호
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• pp.3-10
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• 2018

The folate receptor (FR) is a promising cell membrane-associated target for nuclear imaging of various cancers (via imaging $FR-{\alpha}$) and potentially also inflammatory diseases (via imaging $FR-{\beta}$), through the use of folic acid-based radioconjugates. However, there have been several drawbacks of previously reported radioconjugates, such as a short half-life of the radiolabel ($^{68}Ga\;t_{1/2}$ 68 min), a complex and time-consuming multistep radiosynthesis, and a high renal uptake of radiolabeled folate derivatives. The goal of this study was to develop an imaging probe by directly labeling folate with radioactive iodine without using an extra prosthetic group. The radiolabeling of folate was optimized using various labeling conditions and the labeled tracers were isolated by high-performance liquid chromatography. The in vitro stability of labeled folate was checked in phosphate-buffered saline and serum. The tumor-targeting efficacy of the probe was also evaluated by biodistribution studies using a murine 4T1 tumor model.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.496-502
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• 1998

The present study was carried out to determine the possible use of cTn-I in the cardiac myofibrillar architecture, as a potential target for in vivo radioimmunodetection of cardiac damage in a brain death pig model. Radioiodiantion of the anti-cTn-I 5F4 McAb was carried out by lactoperoxidase method. the percentage iodine incorporation achieved was 70-75%. The radioiodinated McAbs were purified on Sephadex G-25 column and characterised by Paper chromatography, Phast Gel electrophoresis and electroimmunoblotting. Radioiodinated anticTn-I 5F4 McAbs were employed alongside Pyrophosphate($Tc_{99m}$-PPi$) and $Thallium^{201}$ chloride($TI^{201}$) in 24 landrace pigs (brain-dead=18 & sham-operated=6). The percentage cardiac uptake of the radiolabelled antibody injected dose was significantly higher in the brain dead animals(0.196%) as compared to that of sham-operated animals (0.11%). Specific in vivo localization of radiolabelled McAbs in the infarcted cardiac tissue was confirmed by computer-aided reconstruction of 3-D images of the isolated heart. The preliminary results of the study revealed preferential uptake of radiolabelled antibody at the site of myocyte damage resulting from artificially induced brain death.

• 대한방사성의약품학회지
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• 제4권2호
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• pp.85-89
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• 2018

We demonstrate a detail protocol for the radiosynthesis of an $^{125}I$-labeled MSTP prosthetic group and its application to the efficient radiolabeling of human serum albumin (HSA). Radioiodination of the precursor (2) was carried out by using $[^{125}I]$NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified $^{125}I$-labeled MSTP ($[^{125}I]1$) was obtained with high radiochemical yield ($73{\pm}5%$, n = 3) and excellent radiochemical purity (>99%). Site-specific reaction between ($[^{125}I]1$) and HSA gave the $^{125}I$-labeled human serum albumin ($[^{125}I]3$) with more than 99% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly demonstrate that the present radiolabeling method will be useful for the efficient and convenient radiolabeling of thiol-bearing biomolecules.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.113-118
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• 2021

Chitosan is a polysaccharide derived from chitin by deacetylation. Chitosan is non-toxic, biodegradable, and biocompatible, so that it can be used in wide variety of medical applications such as wound healing and antimicrobial biomaterials. It also used as dermal fillers due to its ability to inject with liquid formulations. For investigation on in vivo distribution of these chitosans, Bolton-Hunter-conjugated chitosan (Chitosan-BH) was synthesized by the reaction between the primary amino group of chitosan and N-hydroxysuccinimide ester group of Bolton-Hunter reagent. Then Chitosan-BH was radiolabeled with ¹²⁵I (Chitosan-BH-¹²⁵I) using a Chloramine-T method. The effects of each radiolabeling step on the radiolabeling yield of the final product were tested. The results showed that purification step had significant effects on the radiolabeling yield of the final product. Finally, SPECT/CT images were obtained to evaluate in vivo uptake of the radiolabeled chitosan (Chitosan-BH-¹²⁵I) in several organs. The highest uptake was found in the site of injection at 21 days post-injection. The results of this study suggest that chitosan is expected to be useful for biomaterials of dermal fillers.

• 대한방사성의약품학회지
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• 제8권2호
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• pp.71-76
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• 2022

Indigenous diagnostic dose of ¹³¹I-labeled meta-iodobenzylguanidine ([¹³¹I]mIBG) was prepared via Cu⁺ catalyzed isotope exchange reaction generated in situ by sodium metabisulfite for imaging of neuroblastoma tumor. [¹³¹I]mIBG was produced in overall 85-90% radiochemical yield. The average amount of radioactivity of [¹³¹I]mIBG was 2164 MBq (1998-2331MBq) with an average specific activity > 1000 MBq/mg at the end of synthesis. The radiochemical purity was ≥ 99.9% after purification through Dowex-1 × 8 ion exchange resin (100-150 mesh) at the date of preparation. The stability of [¹³¹I]mIBG at concentration 480-555 MBq/mL was > 97% at 4 ℃ after 4 days. The room temperature (25 ℃) stability of [¹³¹I]mIBG was > 98% after 24 h. Biodistribution of [¹³¹I]mIBG in patient showed uptake in salivary glands, liver, spleen and excreted though urinary bladder. Neuroendocrine medicated uptake into tumor lesion and metastatic sites were noted which strongly correlate with the morphological abnormalities of patient.

• 대한핵의학회지
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• 제27권2호
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• pp.261-269
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• 1993

핵의학 분야에 사용되는 항체의 적절한 동위원소 표지법을 선택하는데는 표지항체의 면역반응성을 평가하는 것이 매우 중요한 일이다. 저자 등은 국내에서 개발된 CEA-79 단세포군 항체를 표지방법 및 비방사능을 $0.1{\mu}Ci/{\mu}g$으로부터 $100{\mu}Ci/{\mu}g$까지 달리하여 $^{125}I$ 표지를 시행한 후 면역반응성을 평가하고, 이 항체에 적절한 표지방법을 찾고자 하였다. 면역반응성의 평가에 있어서는 표지, 비표지 항체의 경쟁반응을 이용하여 표지항체의 비표지항체에 대한 상대적 면역반응성을 평가하는 새로운 방법을 시도해 보았다. 그 결과 CEA-79 항체의 강우, chlormine T법이 iodogen법보다 우수하였는데, 즉, chloramine T법으로 표지시에는 비방사능을 $100{\mu}Ci/{\mu}g$까지 높여도 면역반응성이 잘 유지되고 시간경과에 따른 면역반응성의 변화도 적었다. 본 연구에서 시도한 새로운 경쟁반응방법은 동위원소표지에 의한 항체의 면역반응성의 손상을 평가하는데 효과적이었으며, 기존의 세포결합 검사법보다 간편하였다. 또 항체의 면역반응성은 비방사능과 함께 방사면역계수법의 민감도에 영향을 미침을 확인할 수 있었다. 따라서 표지항체의 면역반응성과 비방사능은 그 용도에 따라 적정화되어야 할 것이며, 본 연구에서 시도한 경쟁반응방법은 적정한 동위원소 표지 방법을 선택하는데 유용할 것으로 사료된다.

• 대한의생명과학회지
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• 제3권2호
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• pp.125-130
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• 1997

Taxol은 diterpenoid구조를 가진 항암제로서, 난소암과 유방암에 탁월한 효과를 보이지만 다른 항암제와 마찬가지로 독성을 가지고 있어 약물의 체내 혈중농도를 모니터링하는 것이 필요하다. 약물의 혈중농도를 모니터링하는 방법은 HPLC법, ELISA법, RIA법 등이 있으나, RIA법이 민감도 측면에서 또한 간편하다는 점에서 장점이 있다. 본 연구에서는 I-125표지항원을 이용한 방사면역측정법을 확립하기 위해 먼저 taxol유도체를 합성하였다. 먼저 taxol의 C-13 탄소의 곁가지에 위치한 C-2'부분의 hydroxy기를 succinic anhydride와 반응시켜 2'-hemisuccinyltaxol (I)을 합성 (반응수율:80%)하였다. 또한 tyramine을 $^{125}$I로 표지하고 gel chromatopaphy를 통해 정제된 [$^{125}$I]iodotyramine (II) (반응수율:58%)을 얻었다. (I)과 (II)를 반응시켜 2'-[$^{125}$I]iodotyramine-hemisuccinyltaxol (III) (반응수율:96%)을 얻어 $^{125}$I 표지항원으로 사용하였다. Taxol에 대한 항체를 획득하기 위해서 (I)을 BSA에 접합반응시켜 2'-hemisuccinyltaxol-BSA접합체를 합성하였으며, 이것을 토끼에 면역 주사하여 anti-taxol serum을 얻었다. 이 항체에 대한 역가 검정실험에서 1:20의 희석비에서 B/F(%)가 약 40%를 보였다. 이와 같은 결과는 2'-[$^{125}$I]iodotyramino-hemisuccinyltaxol을 표지항원으로 한 taxol의 방사면역측정 방법으로 혈청내 taxol의 농도측정이 가능함을 제시해 준다.

• 대한핵의학회지
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• 제36권2호
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• pp.102-109
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• 2002

목적: 유전자 치료에서, 종양세포에 herpes simplex virus thymidine kinase 유전자를 발현시키고 이에 민감한 prodrug을 전신투여하여 발현된 종양세포에 특이적으로 집적되는 방법은 매우 효율적인 방법이다. 대표적인 prodrug인, IVDU, IVFRU는 herpes simplex virus type 1의 비침습적 영상화 방법에 응용되는 방사옥소 표지가능 화합물이다. 재료 및 방법: Trans-l-trimethylsilyl-2-tri-n-butylstannylethylene과 uridine 변형체상의 iodo-uracil을 Pd촉매하에서 반응시켜 표지전구체인 5-trimethylvinyl-deoxy-uridine과 5-trimethylsilylvinyl-deoxy-fluororibofuranosyl uracil을 합성하였다. 이것을 column chromatography의 방법으로 분리 정제하였다. 합성한 각 전구체를 ICI 담체를 이용하여 높은 수율로 표지하였고, HPLC를 사용하여 분리하였다. Radiohalogen exchange 방법은 비방사능을 낮게 할수록 표지에 효율적으로 알려져 있다. 이 방법으로 ICI 방법을 사용하여 담체를 포함하는 높은 방사능의 화합물을 얻을 수 있다. 결과: IVDU와 IVFRU 표지를 위한 전구체 합성수율은 각각 43, 72% 였다. ICl로 담체를 이용한 표지방법을 사용하여 IVDU와 IVFRU 표지수율은 98% 이상이었다. 결론: HSV1-tk를 이용한 유전자 영상용 기질의 전구체를 성공적으로 합성하였고. 95% 이상의 높은 표지수율의 유전자 영상용 방사성 추적자를 성공적으로 제조하였다.