Myung Hee Sohn

Recent Trends in the Nucleophilic [ 18 F]-radiolabeling Method with No-carrier-added [ 18 F]fluoride

Noninvasive imaging in living subjects with positron emission tomography (PET) provides early detection of diseases in humans. For this application, it is necessary to prepare specific molecular imaging probes labeled with positron-emitting radioisotopes such as fluorine-18 for obtaining high-quality PET imaging. In this review, we describe recent trends in the F-18 radiolabeling method for the introduction of no-carrier-added fluorine-18, which was obtained from an 18O(p,n)18F reaction, into a specific molecular site, which in turn is intended to serve as an imaging agent for PET study. These labeling protocols are based on ionic liquid media 18F radiofluorination in the presence of some water, enzymatic 18F fluorination using fluorinase in water solution, non-polar protic alcohol media 18F radiofluorination and its mechanism, and nucleophilic 18F fluorination of an aromatic iodonium salt precursor.

Synthesis and characterization of iron oxide nanoparticles decorated with carboxymethyl curdlan

ConclusionsWe have synthesized the SPION coated with CMC and investigated the stability in water,T2 relaxation rate and cytotoxicity. The coating with CMC improved the stability in water and reduced the cytotoxicity to cell viability. Furthermore, the CMC-coated SPION showed superparamagnetic behaviors. The CMC-coated SPION may be used for cellular andin vivo imaging. When CMC are chemically modified for conjugation of specific ligand, the CMCcoated SPION may have a great potential for biomedical applications.

Synthesis and in vivo evaluation of 99m Tc-Transferrin conjugate for detection of inflamed site.

Transferrin is one of acute phase reactants in inflamed lesion. Expression of transferrin receptor is increased in activated macrophage during inflammation process. Conjugates of target ligand with novel water-soluble chitosan for fast excretion of background radioactivity have been shown to be selectively taken up via the target molecules. In this study, radiolabeled 99mTc–Transferrin conjugate was synthesized and evaluated its efficacy in vivo as a targeted agent for the rapid detection of inflamed lesion that expresses relatively high level of transferrin receptors. Transferrin was conjugated with HYNIC-chitosan and radiolabeled with 99mTc. The biodistribution and scintigraphic images with the 99mTc–HYNIC–chitosan–Transferrin conjugate (99mTc–Tfc) were studied in a murine infection model in which the infection was induced with Escherichia coli (2 × 106 colonies). The %ID/g was as follows: 1.612 ± 0.098, 2.473 ± 0.202 and 2.617 ± 0.646% at 30, 120 min and 6 h after injection, respectively. Gamma camera imaging rapidly visualized the infection/inflammation lesion, with the lesion-to-background ratio improving with time up to 5.68 ± 0.48. 99mTc–Tfc scintigraphy allows rapid and good imaging of an inflamed lesion.

Optical imaging of absorption and distribution of RITC-SiO2 nanoparticles after oral administration

Purpose In this study, we investigated the absorption and distribution of rhodamine B isothiocyanate (RITC)-incorporated silica oxide nanoparticles(SiNPs) (RITC-SiNPs) after oral exposure, by conducting optical imaging, with a focus on tracking the movement of RITC-SiNPs of different particle size and surface charge. Methods RITC-SiNPs (20 or 100 nm; positively or negatively charged) were used to avoid the dissociation of a fluorescent dye from nanoparticles via spontaneous or enzyme-catalyzed reactions in vivo. The changes in the nanoparticle sizes and shapes were investigated in an HCl solution for 6 hours. RITC-SiNPs were orally administered to healthy nude mice at a dose of 100 mg/kg. Optical imaging studies were performed at 2, 4, and 6 hours after oral administration. The mice were sacrificed at 2, 4, 6, and 10 hours post-administration, and ex vivo imaging studies were performed. Results The RITC-SiNPs were stable in the HCl solution for 6 hours, without dissociation of RITC from the nanoparticles and without changes in size and shape. RITC-SiNPs flowed into the small intestine from the stomach and gradually moved along the gut during the experiment. In the ex vivo imaging studies, optical signals were observed mostly in the lungs, liver, pancreas, and kidneys. The orally administered RITC-SiNPs, which were absorbed in the systemic circulation, were eliminated from the body into the urine. The 20 nm RITC-SiNPs showed higher uptake in the lungs than the 100 nm RITC-SiNPs. The distribution of the 100 nm RITC-SiNPs in the liver was higher than that of the 20 nm RITC-SiNPs, but the differences in the surface charge behavior were imperceptible. Conclusion We demonstrated that the movement of RITC-SiNPs after oral exposure could be traced by optical imaging. Optical imaging has the potential to provide valuable information that will help in understanding the behavior of SiNPs in the body following exposure.

Myoid angioendothelioma of the spleen mimicking metastatic disease in a patient with rectal cancer: a radiologic-pathologic correlation.

Myoid angioendothelioma of the spleen is an uncommon, benign vascular tumor that is morphologically characterized by a composite of vascular spaces and stromal cells with myoid feature. Herein, we report a case of the myoid angioendothelioma of the spleen, concurrent with rectal adenocarcinoma. A 41-year-old woman presented with hematochezia for several weeks. Grossly, the rectal mass was a 2.5 × 2-cm ulcerative fungating lesion. The splenic mass was a 2.2 × 2-cm well-circumscribed lesion. Microscopically, the rectal mass was a well-differentiated adenocarcinoma that invaded into the pericolic adipose tissue. The splenic mass was composed of slit-like vascular spaces and fascicles of elongated stromal cells. Vascular endothelial cells were immunopositive for CD31, factor VIII-related antigen, and CD34 but negative for CD8. Stromal cells were immunopositive for smooth muscle actin but negative for desmin.

Treatment of Infected Bulla with Alcohol Sclerosis Combined with Percutaneous Catheter Drainage: A Preliminary Report

Purpose; To evaluate effectiveness of alcohol sclerosis combined with percutaneous catheter drainage (PCD) for treatment of infected bulla. Materials and Methods: Infected bulla in four consecutive patients were treated. In all patients, percutaneous catheter drainage of the bulla was performed . Instillation of sterile alcohol (99% ethano l) was carried out into the cavity of the bulla. Alcohol was left in the cavity for approximately 30 minutes in each session. Alcohol instillation was repeated according to the size of bulla. Patients were subsequently followed up with serial chest radiographs and CT scans. Results: AII patients showed significant improvement both clinically and radiologically. Disappearance of the bulla and reexpansion of surrounding lung parenchyma was observed in two patients and partial resolution (80% reduction in size) was seen in anothertwo patients. Complications included mild chest pain during instillation of alcohol in all patients and delayed radiating shoulder pain in one patient. Conclusion : We provisionally conclude that intracavitary alcohol instillation combined with PCD is effective in thetreatment ofthe infected bulla .