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1.  Preparation and evaluation of poly(2-hydroxyethyl aspartamide)-hexadecylamine-iron oxide for MR imaging of lymph nodes 
The purpose of this study was to synthesize biocompatible poly(2-hydroxyethyl aspartamide)–C16-iron oxide (PHEA-C16-iron oxide) nanoparticles and to evaluate their efficacy as a contrast agent for magnetic resonance imaging of lymph nodes. The PHEA-C16-iron oxide nanoparticles were synthesized by coprecipitation method. The core size of the PHEA-C16-iron oxide nanoparticles was about 5 to 7 nm, and the overall size of the nanoparticles was around 20, 60, and 150 nm in aqueous solution. The size of the nanoparticles was controlled by the amount of C16. The 3.0-T MRI signal intensity of a rabbit lymph node was effectively reduced after intravenous administration of PHEA-C16-iron oxide with the size of 20 nm. The in vitro and in vivo toxicity tests revealed the high biocompatibility of PHEA-C16-iron oxide nanoparticles. Therefore, PHEA-C16-iron oxide nanoparticles with 20-nm size can be potentially useful as T2-weighted MR imaging contrast agents for the detection of lymph nodes.
doi:10.1186/1556-276X-9-38
PMCID: PMC3931668  PMID: 24438671
Magnetic resonance imaging; Lymph node; Ultrasuperparamagnetic iron oxide; Nanoparticles
2.  SPONTANEOUS TUMOR REGRESSION IN A SYNGENEIC RAT MODEL OF LIVER CANCER: IMPLICATIONS FOR SURVIVAL STUDIES 
Purpose
The aim of this study was to characterize tumor growth of N1S1 cells implanted into the liver of Sprague Dawley rats in order to determine if this model could be used for survival studies. These results were compared with tumor growth after implantation with McA-RH77777 cells.
Materials and Methods
N1S1 cells or McA-RH77777 cells were implanted into the liver of Sprague Dawley rats (n=20 and n=12, respectively) using ultrasound (US) and tumor growth was followed using US. Additionally, we compared the serum profile of 19 cytokines in naïve rats to tumor bearing rats.
Results
Both types of tumors were visible on US imaging 1 week after tumor implantation, but the mean tumor volume of N1S1 tumors was larger compared to McA-RH7777 tumors (231 mm3 versus 82.3 mm3, respectively). Tumor volumes in both groups continued to increase reaching a mean tumor volume of 289 mm3 and 160 mm3 in the N1S1 and McA-RH7777 group, respectively, 2 weeks post tumor implant. By week 3, tumor volumes had declined considerably, and 6 (50%) tumors in the McA-RH7777 had spontaneously regressed, versus 2 (10%) tumors in the N1S1 group. Tumor volumes continued to decrease over the following 3 weeks, and complete tumor regression of all tumors was seen 5 weeks and 6 weeks after tumor implantation in the McA-RH7777 and N1S1 group, respectively. In an N1S1 implanted rat, multiple cytokines that have been shown to correlate with the ability of the tumor to survive in a hostile environment were increased by up to 50%, whereas the average increase in cytokine levels was 90%. These findings suggest that the net cytokine environment favors an anti-tumor immune response. A similar trend was observed in a rat with a McA-RH77777 tumor, and the increase in cytokine levels was considerably more pronounced with an average increase of 320%.
Conclusion
We therefore conclude that this model cannot be used for survival studies, and should only be used with great caution in short-term studies that involve cancer therapies.
doi:10.1016/j.jvir.2012.08.025
PMCID: PMC3548324  PMID: 23177115
3.  Engraftment of Human Mesenchymal Stem Cells in a Rat Photothrombotic Cerebral Infarction Model : Comparison of Intra-Arterial and Intravenous Infusion Using MRI and Histological Analysis 
Objective
This study aimed to evaluate the hypotheses that administration routes [intra-arterial (IA) vs. intravenous (IV)] affect the early stage migration of transplanted human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in acute brain infarction.
Methods
Male Sprague-Dawley rats (n=40) were subjected to photothrombotic infarction. Three days after photothrombotic infarction, rats were randomly allocated to one of four experimental groups [IA group : n=12, IV group : n=12, superparamagnetic iron oxide (SPIO) group : n=8, control group : n=8]. All groups were subdivided into 1, 6, 24, and 48 hours groups according to time point of sacrifice. Magnetic resonance imaging (MRI) consisting of T2 weighted image (T2WI), T2* weighted image (T2*WI), susceptibility weighted image (SWI), and diffusion weighted image of rat brain were obtained prior to and at 1, 6, 24, and 48 hours post-implantation. After final MRI, rats were sacrificed and grafted cells were analyzed in brain and lung specimen using Prussian blue and immunohistochemical staining.
Results
Grafted cells appeared as dark signal intensity regions at the peri-lesional zone. In IA group, dark signals in peri-lesional zone were more prominent compared with IV group. SWI showed largest dark signal followed by T2*WI and T2WI in both IA and IV groups. On Prussian blue staining, IA administration showed substantially increased migration and a large number of transplanted hBM-MSCs in the target brain than IV administration. The Prussian blue-positive cells were not detected in SPIO and control groups.
Conclusion
In a rat photothrombotic model of ischemic stroke, selective IA administration of human mesenchymal stem cells is more effective than IV administration. MRI and histological analyses revealed the time course of cell migration, and the numbers and distribution of hBM-MSCs delivered into the brain.
doi:10.3340/jkns.2013.54.6.467
PMCID: PMC3921273  PMID: 24527188
MRI; Mesenchymal stem cell; Photothrombotic cerebral infarction; Superparamagnetic iron oxide; Intravascular
4.  Tracing of the Bile-Chemotactic Migration of Juvenile Clonorchis sinensis in Rabbits by PET-CT 
Background
Adult Clonorchis sinensis live in the bile duct and cause clonorchiasis. It is known that the C. sinensis metacercariae excyst in the duodenum and migrate up to the bile duct through the common bile duct. However, no direct evidence is available on the in vivo migration of newly excysted C. sinensis juveniles (CsNEJs). Advanced imaging technologies now allow the in vivo migration and localization to be visualized. In the present study, we sought to determine how sensitively CsNEJs respond to bile and how fast they migrate to the intrahepatic bile duct using PET-CT.
Methodology/Principal Findings
CsNEJs were radiolabeled with 18F-fluorodeoxyglucose (18F-FDG). Rabbits with a gallbladder contraction response to cholecystokinin-8 (CCK-8) injection were pre-screened using cholescintigraphy. In these rabbits, gallbladders contracted by 50% in volume at an average of 11.5 min post-injection. The four rabbits examined were kept anesthetized and a catheter inserted into the mid duodenum. Gallbladder contraction was stimulated by injecting CCK-8 (20 ng/kg every minute) over the experiment. Anatomical images were acquired by CT initially and dynamic PET was then carried out for 90 min with a 3-min acquisition per frame. Twelve minutes after CCK-8 injection, about 3,000 18F-FDG-labeled CsNEJs were inoculated into the mid duodenum through the catheter. Photon signals were detected in the liver 7–9 min after CsNEJs inoculation, and these then increased in the whole liver with stronger intensity in the central area, presenting that the CsNEJs were arriving at the intrahepatic bile ducts.
Conclusion
In the duodenum, CsNEJs immediately sense bile and migrate quickly with bile-chemotaxis to reach the intrahepatic bile ducts by way of the ampulla of Vater.
Author Summary
Clonorchis sinensis adults habituating in the bile duct cause clonorchiasis endemic in East Asian countries, in which about 15–20 million people are supposedly infected. It has previously been reported that C. sinensis metacercariae excyst in the duodenum and that the juvenile flukes migrate to the bile duct through the ampulla of Vater in 4–7 hours. Recently advanced imaging technologies have enabled visualization of movements and localizations of parasites in mammalian hosts. From present study, we found the following: newly excysted C. sinensis juveniles (CsNEJs) were efficiently in vitro radiolabeled with 18F-FDG since CsNEJs have glucose transporters; CCK-8-induced gallbladder contraction was various rabbit to rabbit; CsNEJs promptly recognized bile and migrated up the duodenum to reach the intrahepatic bile ducts by way of the ampulla of Vater and the common bile duct as early as 7–9 minutes after inoculation. Some CsNEJs responding slowly to the bile delayed arriving at the distal bile capillaries. It was visualized for the first time that the CsNEJs migrate quickly within 10–20 minutes from the duodenum to the intrahepatic bile duct. These findings provide fundamental information on the migration of parasites living in the biliary passages of mammals.
doi:10.1371/journal.pntd.0001414
PMCID: PMC3236719  PMID: 22180795
5.  Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents 
Nanoscale Research Letters  2010;5(12):1970-1976.
Biocompatible poly-[N-(2-hydroxyethyl)-d,l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd.
doi:10.1007/s11671-010-9734-7
PMCID: PMC2991228  PMID: 21170410
MRI contrast agent; PHEA derivatives; Micelles; Nanoparticles; Gd contrast agent
6.  Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents 
Nanoscale Research Letters  2010;5(12):1970-1976.
Biocompatible poly-[N-(2-hydroxyethyl)-d,l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd.
doi:10.1007/s11671-010-9734-7
PMCID: PMC2991228  PMID: 21170410
MRI contrast agent; PHEA derivatives; Micelles; Nanoparticles; Gd contrast agent
7.  Transcatheter Arterial Embolization in Patients with Kidney Diseases: an Overview of the Technical Aspects and Clinical Indications 
Korean Journal of Radiology  2010;11(3):257-268.
Therapeutic embolization is defined as the voluntary occlusion of one or several vessels, and this is achieved by inserting material into the lumen to obtain transient or permanent thrombosis in the downstream vascular bed. There are a number of indications for this approach in urological practice, in particular for the patients with parenchymatous or vascular kidney disease. In this review, we present the different embolization techniques and the principally employed occluding agents, and then we present the principal clinical indications and we discuss other pathologies that may benefit from this non-invasive therapy. The complications, side effects and main precautions associated with this approach are also described.
doi:10.3348/kjr.2010.11.3.257
PMCID: PMC2864852  PMID: 20461179
Kidney; Arterial embolization; Interventional radiology; Surgery
8.  In vivo Tracking of Mesenchymal Stem Cells Labeled with a Novel Chitosan-coated Superparamagnetic Iron Oxide Nanoparticles using 3.0T MRI 
Journal of Korean Medical Science  2010;25(2):211-219.
This study aimed to characterize and MRI track the mesenchymal stem cells labeled with chitosan-coated superparamagnetic iron oxide (Chitosan-SPIO). Chitosan-SPIO was synthesized from a mixture of FeCl2 and FeCl3. The human bone marrow derived mesenchymal stem cells (hBM-MSC) were labeled with 50 µg Fe/mL chitosan-SPIO and Resovist. The labeling efficiency was assessed by iron content, Prussian blue staining, electron microscopy and in vitro MR imaging. The labeled cells were also analyzed for cytotoxicity, phenotype and differentiation potential. Electron microscopic observations and Prussian blue staining revealed 100% of cells were labeled with iron particles. MR imaging was able to detect the labeled MSC successfully. Chitosan-SPIO did not show any cytotoxicity up to 200 µg Fe/mL concentration. The labeled stem cells did not exhibit any significant alterations in the surface markers expression or adipo/osteo/chondrogenic differentiation potential when compared to unlabeled control cells. After contralateral injection into rabbit ischemic brain, the iron labeled stem cells were tracked by periodical in vivo MR images. The migration of cells was also confirmed by histological studies. The novel chitosan-SPIO enables to label and track MSC for in vivo MRI without cellular alteration.
doi:10.3346/jkms.2010.25.2.211
PMCID: PMC2811286  PMID: 20119572
Chitosan; Mesenchymal Stem Cells; Superparamagnetic Iron Oxide; Magnetic Resonance Imaging; Brain Ischemia
9.  Perforated duodenal ulcer presenting with massive hematochezia in a 30-month-old child 
Peptic ulcer disease is uncommon in children and rarely suspected as a cause of abdominal complaints in this age group; the diagnosis is therefore made almost exclusively when complications develop. Peptic ulcer disease is usually not considered in the differential diagnosis of pediatric patients. We present the case of a 30-month-old boy with duodenal perforation due to a peptic ulcer without a known etiology. The patient was admitted through the emergency department due to severe hematochezia and ongoing anemia; he presented with neither abdominal pain nor abdominal distension. There were no medical problems, and no drugs, such as corticosteroids or nonsteroidal anti-inflammatory drugs, had been prescribed or administered recently. We tried to control the active bleeding by medical treatment including arterial embolization, but the active bleeding was not controlled. Finally, an exploratory laparotomy was performed. A discrete anterior perforation with active bleeding of the duodenal wall was found. After the operation, there were no complications and the patient recovered fully.
doi:10.3748/wjg.15.4853
PMCID: PMC2761568  PMID: 19824124
Duodenal ulcer; Peptic ulcer perforation; Children; Hematochezia; Hemorrhage
10.  Fixation Methods for Implantable Port Chamber: Comparative Study Using Glue, Self-stabilizing Leg and Suture Fixations in Rabbits 
Korean Journal of Radiology  2004;5(4):266-273.
Objective
To evaluate the fixation strength and tissue reaction of the glue fixation and self-stabilizing leg fixation methods and to compare the results with those of the conventional tagging suture fixation method.
Materials and Methods
Twelve healthy rabbits were selected and three different methods of implanting the port chamber were employed on the back of each rabbit. A total of thirty six port chambers were implanted with these three different methods, viz. the glue fixation method using tissue adhesive, the self-stabilizing leg method using a self-expandable stabilizing leg, and the suture fixation method. The fixation strength and the gross and histopathologic changes of each fixation method were evaluated at three days, one week, two weeks and four weeks after port implantation.
Results
The glue fixation method showed a good fixation strength, which was similar to that of the tagging suture method (p = 0.3486). Five of the six ports (83%) implanted with the glue fixation method which were examined after two weeks showed cracks on the external surface, but this had no adverse effects on their function. A large amount of granulation tissue reaction was found at the bottom of the chamber (p = 0.0025). The fixation with the self-stabilizing leg showed relatively lower fixation strength (p = 0.0043), but no turning-over of the chamber occurred. The fixation strength improved with time after the first week, and minimal granulation tissue reaction was observed with this method.
Conclusion
The glue fixation method exhibited equal fixation strength compared to the suture fixation, but showed cracking and a large amount of granulation tissue, whereas the fixation with a self-stabilizing leg showed weaker fixation strength.
doi:10.3348/kjr.2004.5.4.266
PMCID: PMC2698171  PMID: 15637477
Catheters and catheterization, technology; Interventional procedures, comparative studies; Interventional procedures, experimental; Soft tissues
11.  Tuberculous Aneurysm of the Abdominal Aorta: Endovascular Repair Using Stent Grafts in Two Cases 
Korean Journal of Radiology  2000;1(4):215-218.
Tuberculous aneurysm of the aorta is exceedingly rare. To date, the standard therapy for mycotic aneurysm of the abdominal aorta has been surgery involving in-situ graft placement or extra-anatomic bypass surgery followed by effective anti-tuberculous medication. Only recently has the use of a stent graft in the treatment of tuberculous aortic aneurysm been described in the literature. We report two cases in which a tuberculous aneurysm of the abdominal aorta was successfully repaired using endovascular stent grafts. One case involved is a 42-year-old woman with a large suprarenal abdominal aortic aneurysm and a right psoas abscess, and the other, a 41-year-old man in whom an abdominal aortic aneurysm ruptured during surgical drainage of a psoas abscess.
doi:10.3348/kjr.2000.1.4.215
PMCID: PMC2718204  PMID: 11752958
Aorta, disease; Aorta, aneurysm; Aorta, grafts and prostheses

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