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1.  Alternative Techniques for Cannulation of Biliary Strictures Resistant to the 0.035" System Following Living Donor Liver Transplantation 
Korean Journal of Radiology  2012;13(2):189-194.
To assess the clinical efficacy of alternative techniques for biliary stricture cannulation in patients undergoing living donor liver transplantation (LDLT), after cannulation failure with a conventional (0.035-inch guidewire) technique.
Subjects and Methods
Of 293 patients with biliary strictures after LDLT, 19 (6%) patients, 11 men and 8 women of mean age 48.5 years, had the failed cannulation of the stricture by conventional techniques. Recannulation was attempted by using two alternative methods, namely a micro-catheter set via percutaneous access and a snare (rendezvous) technique using percutaneous and endoscopic approaches.
Strictures were successfully cannulated in 16 (84%) of the 19 patients. A microcatheter set was used in 12 and a snare technique in four patients. Stricture cannulation failed in the remaining three patients, who finally underwent surgical revision.
Most technical failures using a conventional technique for biliary stricture cannulation after LDLT can be overcome by using a microcatheter set or a snare (rendezvous) technique.
PMCID: PMC3303902  PMID: 22438686
Living donor liver transplantation; Biliary complications; Endoscopy; Fluoroscopy
2.  The role of clusterin in retinal development and free radical damage 
The British Journal of Ophthalmology  2007;91(11):1541-1546.
To assess the role of clusterin in retinal vascular development and in free radical damage in vivo and in vitro.
The expression of clusterin, von Willebrand factor (vWF), flk‐1, heat shock protein 27 (Hsp27) and heat shock protein 70 (Hsp70) was examined in the retinas of developing mice and oxygen‐induced retinopathy (OIR) mice by immunofluorescence staining and western blot analysis. Hydrogen peroxide (H2O2)‐pretreated human retinal endothelial cells (HREC) and astrocytes were cultured in the presence or absence of exogenous clusterin, and then the cell viability was measured using the MTT assay and DAPI staining.
Clusterin was expressed mainly in the inner retina and co‐localised with vWF, an endothelial cell marker. During the mouse developmental process, clusterin expression was decreased, which was similar to the expression of flk‐1, vWF and Hsp27. Furthermore, in the OIR model, clusterin expression changed in a similar way to both vWF and Hsp27. Under hypoxic conditions, clusterin expression increased in HREC and astrocytes. In H2O2‐pretreated HREC and astrocytes, clusterin protected against apoptotic cell death.
These results suggest that clusterin is associated with protection from apoptotic retinal cell death in retinal development and in free radical damage.
PMCID: PMC2095423  PMID: 17475708
3.  Gallotannin suppresses calcium oxalate crystal binding and oxalate-induced oxidative stress in renal epithelial cells 
Calcium oxalate monohydrate (COM) crystals bind avidly to the surface of proliferating and migrating renal endothelial cells, perhaps a key event in kidney stone formation. Oxalate-induced pre-oxidative stress can further promote crystal attachment cells. Natural products including gallotannins found in green teas have been studied as potentially novel treatments to prevent crystal retention and kidney stone formation. Gallotannin significantly inhibited COM crystal growth and binding to MDCK I renal epithelial cells at non-toxic concentrations and also delayed renal cell migration in a wound healing assay. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that gallotannin significantly attenuated oxalate-induced mRNA expression of monocyte chemoattractant protein 1 (MCP-1), osteopontin (OPN), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p22phox and p47phox in human primary renal epithelial cells (HRCs). Gallotannin also reduced HRC production of reactive oxygen species (ROS) and malondialdehyde (MDA) as well as enhanced antioxidant enzyme superoxide dismutase (SOD) activity in response to oxalate. Taken together, our findings suggest that gallotannin can contribute to nephrolithiasis prevention via direct effects on renal epithelial cells including suppression of COM binding and MCP-1 and OPN expression, along with augmenting antioxidant activity.
PMCID: PMC3910304  PMID: 22466558
gallotannin; renal epithelial cells; calcium oxalate monohydrate; MCP-1; osteopontin; ROS; SOD
4.  Covered Stent Placement for the Treatment of Malignant Superior Vena Cava Syndrome: Is Unilateral Covered Stenting Safe and Effective? 
Korean Journal of Radiology  2014;15(1):87-94.
To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome.
Materials and Methods
Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins.
Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively.
Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.
PMCID: PMC3909867  PMID: 24497797
Malignant superior vena cava syndrome; Covered stent
5.  The Effect of Bevacizumab versus Ranibizumab in the Treatment of Corneal Neovascularization: A Preliminary Study 
To compare the short term effects of bevacizumab and ranibizumab injections on the regression of corneal neovascularization (NV).
Sixteen eyes of 16 patients with corneal NV were randomly assigned for an injection with 2.5 mg of bevacizumab (group 1, n = 8) or 1 mg of ranibizumab (group 2, n = 8) through subconjunctival and intrastromal routes. The patients were prospectively followed-up for one month after the injections. Corneal NV areas, as shown on corneal slit-lamp photographs stored in JPEG format, were calculated using Image J software before the injection, one week after the injection, and one month after the injection. The corneal NV areas were compared before and after the injections.
Seven women and nine men, with an average age of 51 years, presented with corneal NV secondary to herpetic keratitis (7 cases), graft rejection (6), chemical burn (1), pemphigoid (1), and recurrent ulcer (1). In group I, the preoperative corneal NV area (8.75 ± 4.33%) was significantly decreased to 5.62 ± 3.86% one week after the injection and to 6.35 ± 3.02% one month after the injection (p = 0.012, 0.012, respectively). The corneal NV area in group 2 also exhibited a significant change, from 7.37 ± 4.33% to 6.72 ± 4.16% one week after the injection (p = 0.012). However, no significant change was observed one month after the injection. The mean decrease in corneal NV area one month after injection in group 1 (28.4 ± 9.01%) was significantly higher than in group 2 (4.51 ± 11.64%, p = 0.001).
Bevacizumab injection resulted in a more effective and stable regression of corneal NV compared to the ranibizumab injection. The potency and dose of these two drugs for the regression of corneal NV require further investigation.
PMCID: PMC3730064  PMID: 23908568
Bevacizumab; Corneal neovascularization; Ranibizumab
6.  Orthotopic transplantation of retinoblastoma cells into vitreous cavity of zebrafish for screening of anticancer drugs 
Molecular Cancer  2013;12:71.
With high throughput screening, novel therapeutic agents can be efficiently identified. Unfortunately, researchers only resort to in vitro cell viability assays for screening of anticancer drugs for retinoblastoma, the most common intraocular cancer in the childhood. Current available animal models of retinoblastoma require more than 2 weeks for tumour formation and the investigation of the efficacy of therapeutic agents. In this study, we established a novel orthotopic transplantation model of retinoblastoma in zebrafish as an in vivo animal model for screening of anticancer drugs.
We injected retinoblastoma cells into the vitreous cavity of zebrafish at 48 hours after fertilization. Eyeballs of zebrafish were scanned daily under the confocal laser microscope, and the tumor population was quantitatively analyzed by measuring the mean intensity of green fluorescent protein (GFP). Transplanted retinoblastoma cells were isolated to perform further analyses including Western blotting and reverse transcriptase-polymerase chain reaction to confirm that retinoblastoma cells maintained their characteristics as tumor cells even after transplantation and further isolation. To figure out the potential of this model for screening of anticancer drugs, zebrafish were cultured in Ringer’s solution containing carboplatin and melphalan after the injection of retinoblastoma cells.
The degree of the tumor population was dependent on the number of retinoblastoma cells injected and maintained stably for at least 4 days. Transplanted retinoblastoma cells maintain their proliferative potential and characteristics as retinoblastoma cells after isolation. Interestingly, systemic application of carboplatin and melphalan demonstrated significant reduction in the tumor population, which could be quantitatively analyzed by the estimation of the mean intensity of GFP.
This orthotopic retinoblastoma model in zebrafish is expected to be utilized for the screening of anticancer drugs for the treatment of retinoblastoma.
PMCID: PMC3707771  PMID: 23835085
Anticancer drug screen; Orthotopic transplantation; Retinoblastoma; Zebrafish
7.  Animal models of diabetic retinopathy: doors to investigate pathogenesis and potential therapeutics 
Effective and validated animal models are valuable to investigate the pathogenesis and potential therapeutics for human diseases. There is much concern for diabetic retinopathy (DR) in that it affects substantial number of working population all around the world, resulting in visual deterioration and social deprivation. In this review, we discuss animal models of DR based on different species of animals from zebrafish to monkeys and prerequisites for animal models. Despite criticisms on imprudent use of laboratory animals, we hope that animal models of DR will be appropriately utilized to deepen our understanding on the pathogenesis of DR and to support our struggle to find novel therapeutics against catastrophic visual loss from DR.
PMCID: PMC3694455  PMID: 23786217
Animal model; Diabetic retinopathy; Macular edema; Pathologic angiogenesis; Vascular permeabilit
8.  Human Apolipoprotein(a) Kringle V Inhibits Ischemia-Induced Retinal Neovascularization via Suppression of Fibronectin-Mediated Angiogenesis 
Diabetes  2012;61(6):1599-1608.
Retinal neovascularization is observed in progression of diabetic retinopathy. New vessels grow into the vitreous cavity in proliferative diabetic retinopathy, resulting in traction retinal detachment and vitreous hemorrhage. To overcome the catastrophic visual loss due to these complications, efforts have been focused on the treatment of retinal neovascularization. In this study, we demonstrated the inhibitory effect of recombinant human apolipoprotein(a) kringle V (rhLK8) in an animal model of ischemia-induced retinal neovascularization. rhLK8 induced no definite toxicity on endothelial cells and retinal tissues at the therapeutic dosage. Interestingly, rhLK8 showed antiangiogenic effect, particularly on fibronectin-mediated migration of endothelial cells. Further experiments demonstrated high binding affinity of rhLK8 to α3β1 integrin, and suppression of it might be the mechanism of antiangiogenic effect of rhLK8. Furthermore, rhLK8 inhibited phosphorylation of focal adhesion kinase, resulting in suppression of activation of consequent p130CAS-Jun NH2-terminal kinase. Taken together, our data suggested the possible application of rhLK8 in the treatment of retinal neovascularization by suppression of fibronectin-mediated angiogenesis.
PMCID: PMC3357289  PMID: 22427380
9.  Decursin and Doxorubicin Are in Synergy for the Induction of Apoptosis via STAT3 and/or mTOR Pathways in Human Multiple Myeloma Cells 
Background. Combination cancer therapy is one of the attractive approaches to overcome drug resistance of cancer cells. In the present study, we investigated the synergistic effect of decursin from Angelica gigas and doxorubicin on the induction of apoptosis in three human multiple myeloma cells. Methodology/Principal Findings. Combined treatment of decursin and doxorubicin significantly exerted significant cytotoxicity compared to doxorubicin or decursin in U266, RPMI8226, and MM.1S cells. Furthermore, the combination treatment enhanced the activation of caspase-9 and -3, the cleavage of PARP, and the sub G1 population compared to either drug alone in three multiple myeloma cells. In addition, the combined treatment downregulated the phosphorylation of mTOR and its downstream S6K1 and activated the phosphorylation of ERK in three multiple myeloma cells. Furthermore, the combined treatment reduced mitochondrial membrane potential, suppressed the phosphorylation of JAK2, STAT3, and Src, activated SHP-2, and attenuated the expression of cyclind-D1 and survivin in U266 cells. Conversely, tyrosine phosphatase inhibitor pervanadate reversed STAT3 inactivation and also PARP cleavage and caspase-3 activation induced by combined treatment of doxorubicin and decursin in U266 cells. Conclusions/Significance. Overall, the combination treatment of decursin and doxorubicin can enhance apoptotic activity via mTOR and/or STAT3 signaling pathway in multiple myeloma cells.
PMCID: PMC3684033  PMID: 23818927
10.  Inhibition of Connexin 26/43 and Extracellular-Regulated Kinase Protein Plays a Critical Role in Melatonin Facilitated Gap Junctional Intercellular Communication in Hydrogen Peroxide-Treated HaCaT Keratinocyte Cells 
Though melatonin was known to regulate gap junctional intercellular communication (GJIC) in chick astrocytes and mouse hepatocytes, the underlying mechanism by melatonin was not elucidated in hydrogen peroxide- (H2O2-) treated HaCaT keratinocyte cells until now. In the current study, though melatonin at 2 mM and hydrogen peroxide (H2O2) at 300 μM showed weak cytotoxicity in HaCaT keratinocyte cells, melatonin significantly suppressed the formation of reactive oxygen species (ROS) in H2O2-treated HaCaT cells compared to untreated controls. Also, the scrape-loading dye-transfer assay revealed that melatonin enhances the intercellular communication by introducing Lucifer Yellow into H2O2-treated cells. Furthermore, melatonin significantly enhanced the expression of connexin 26 (Cx26) and connexin 43 (Cx43) at mRNA and protein levels, but not that of connexin 30 (Cx30) in H2O2-treated HaCaT cells. Of note, melatonin attenuated the phosphorylation of extracellular signal-regulated protein kinases (ERKs) more than p38 MAPK or JNK in H2O2-treated HaCaT cells. Conversely, ERK inhibitor PD98059 promoted the intercellular communication in H2O2-treated HaCaT cells. Furthermore, combined treatment of melatonin (200 μM) and vitamin C (10 μg/mL) significantly reduced ROS production in H2O2-treated HaCaT cells. Overall, these findings support the scientific evidences that melatonin facilitates gap junctional intercellular communication in H2O2-treated HaCaT keratinocyte cells via inhibition of connexin 26/43 and ERK as a potent chemopreventive agent.
PMCID: PMC3518788  PMID: 23243457
11.  Role of Heat Shock Protein 47 in Transdifferentiation of Human Tenon's Fibroblasts to Myofibroblasts 
BMC Ophthalmology  2012;12:49.
Heat shock protein 47 (Hsp47) is a well-known molecular chaperone in collagen synthesis and maturation. The aim of this study is to investigate its putative role in the transdifferentiation of Tenon’s fibroblasts to myofibroblasts.
Primary cultured human Tenon’s fibroblasts were exposed to transforming growth factor-β1 (TGF-β1) for up to 48 hours. The mRNA levels of Hsp47 and α smooth muscle actin (αSMA) were determined by quantitative real time RT-PCR. After delivery of small interfering RNA (siRNA) molecules targeting Hsp47 into the cells, the expression of Hsp47 and αSMA proteins was determined by western immunoblotting.
TGF-β1 increased the mRNA expressions of both Hsp47 and αSMA in human Tenon’s fibroblasts, as determined by quantitative real time RT-PCR. However, it induced the protein expression of only αSMA but not Hsp47, as determined by western immunoblots. When siRNAs specific for Hsp47 were introduced into those cells, the TGF-β1-induced expression of αSMA was significantly attenuated on western immunoblots; after 48 hours of exposure to TGF-β1, the relative densities of immunobands were 11.58 for the TGF-β1 only group and 2.75 for the siRNA treatment group, compared with the no treatment control group (p < 0.001).
Our data suggest that Hsp47 may be related to the TGF-β1-induced transdifferentiation of human Tenon’s fibroblasts to myofibroblasts.
PMCID: PMC3490793  PMID: 22967132
Fibroblast; Fibrosis; Heat shock protein; Myofibroblast; Transforming growth factor-β
12.  Correction: Inhibitory Activity of Bevacizumab to Differentiation of Retinoblastoma Cells 
PLoS ONE  2012;7(5):10.1371/annotation/008b05a8-229b-4aca-94ae-91e6dd5ca5ba.
PMCID: PMC3355184
13.  Inhibitory Activity of Bevacizumab to Differentiation of Retinoblastoma Cells 
PLoS ONE  2012;7(3):e33456.
Vascular endothelial growth factor (VEGF) is a major regulator in retinal and choroidal angiogenesis, which are common causes of blindness in all age groups. Recently anti-VEGF treatment using anti-VEGF antibody has revolutionarily improved the visual outcome in patients with vaso-proliferative retinopathies. Herein, we demonstrated that bevacizumab as an anti-VEGF antibody could inhibit differentiation of retinoblastoma cells without affection to cellular viability, which would be mediated via blockade of extracellular signal-regulated kinase (ERK) 1/2 activation. The retinoblastoma cells expressed VEGFR-2 as well as TrkA which is a neurotrophin receptor associated with differentiation of retinoblastoma cells. TrkA in retinoblastoma cells was activated with VEGF treatment. Interestingly even in the concentration of no cellular death, bevascizumab significantly attenuated the neurite formation of differentiated retinoblastoma cells, which was accompanied by inhibition of neurofilament and shank2 expression. Furthermore, bevacizumab inhibited differentiation of retinoblastoma cells by blockade of ERK 1/2 activation. Therefore, based on that the differentiated retinoblastoma cells are mostly photoreceptors, our results suggest that anti-VEGF therapies would affect to the maintenance or function of photoreceptors in mature retina.
PMCID: PMC3310877  PMID: 22457763
14.  Incidence and Management of Bleeding Complications Following Percutaneous Radiologic Gastrostomy 
Korean Journal of Radiology  2012;13(2):174-181.
Upper gastrointestinal (GI) bleeding is a serious complication that sometimes occurs after percutaneous radiologic gastrostomy (PRG). We evaluated the incidence of bleeding complications after a PRG and its management including transcatheter arterial embolization (TAE).
Materials and Methods
We retrospectively reviewed 574 patients who underwent PRG in our institution between 2000 and 2010. Eight patients (1.4%) had symptoms or signs of upper GI bleeding after PRG.
The initial presentation was hematemesis (n = 3), melena (n = 2), hematochezia (n = 2) and bloody drainage through the gastrostomy tube (n = 1). The time interval between PRG placement and detection of bleeding ranged from immediately after to 3 days later (mean: 28 hours). The mean decrease in hemoglobin concentration was 3.69 g/dL (range, 0.9 to 6.8 g/dL). In three patients, bleeding was controlled by transfusion (n = 2) or compression of the gastrostomy site (n = 1). The remaining five patients underwent an angiography because bleeding could not be controlled by transfusion only. In one patient, the bleeding focus was not evident on angiography or endoscopy, and wedge resection including the tube insertion site was performed for hemostasis. The other four patients underwent prophylactic (n = 1) or therapeutic (n = 3) TAEs. In three patients, successful hemostasis was achieved by TAE, whereas the remaining one patient underwent exploration due to persistent bleeding despite TAE.
We observed an incidence of upper GI bleeding complicating the PRG of 1.4%. TAE following conservative management appears to be safe and effective for hemostasis.
PMCID: PMC3303900  PMID: 22438684
Percutaneous radiologic gastrostomy; Bleeding; Transcatheter arterial embolization
15.  Dual-Design Expandable Colorectal Stent for a Malignant Colorectal Obstruction: Preliminary Prospective Study Using New 20-mm Diameter Stents 
Korean Journal of Radiology  2011;13(1):66-72.
To evaluate the safety and effectiveness of a 20-mm diameter dual-design expandable colorectal stent for malignant colorectal obstruction.
Materials and Methods
The study series included 34 patients with malignant colorectal obstruction who underwent implantation of a 20-mm dual-design expandable colorectal stent in our department between March 2009 and June 2010. The 20-mm dual-design expandable colorectal stent was placed by using a 3.8-mm delivery system that had 28-mm diameter proximal and distal ends. Among the 34 patients, stent placement for palliation was performed in 20 patients, while stent placement for bridge to surgery was performed in 14 patients.
A 97% (33 of 34) success rate was achieved for the stent placement. The perforation rate in the bridge to surgery group was 7% (1 of 14), compared to 0% (0 of 19) in palliative group. Migration occurred in one of 33 patients (3%) at 30 days after stent placement.
The placement of a 20-mm diameter dual-design stent appears to be clinically safe and effective for the management of colorectal obstruction, with low perforation and migration rates.
PMCID: PMC3253405  PMID: 22247638
Colorectal cancer; Stent; Dual-design; Expandable
16.  Intravenously Administered Anti-recoverin Antibody Alone Does Not Pass through the Blood-Retinal Barrier 
Cancer-associated retinopathy is a paraneoplastic retinal degeneration which may primarily result from auto-immune mediated apoptosis. It has been hypothesized that high titer of auto-antibodies are able to cross the blood-retinal barrier (BRB) and to enter retinal cells to activate apoptotic pathway which has been already well-established. However, it still remains to be elucidated whether auto-antibodies could cross BRB in the retina. Herein, we demonstrated that intravenously administrated anti-recoverin antibodies could not pass through BRB and not lead to retinal cell death.
Anti-recoverin antibody was intravenously injected to C57BL/6 mice, which were sacrificed 1 and 7 days to obtain eye. Vascular endothelial growth factor was intravitreally injected to induce BRB breakdown, which was confirmed by fluorescein angiography and western blotting for zonula occludens (ZO)-1, ZO-2 and occludin. To investigate the location of anti-recoverin antibody in the retina, immunofluorescein was performed. The retinal toxicity of intravenous anti-recoverin antibody was evaluated by histological examination and transferase-mediated dUTP nick-end labeling. Immunofluorescein staining for glial fibrillary acidic protein was done to address glial activation as well.
Intravenously administrated anti-recoverin antibodies were exclusively distributed on retinal vessels which were co-localized with CD31, and led to neither increase of glial fibrillary acidic protein expression, as an indicator of retinal stress, nor apoptotic retinal cell death. Moreover, even in the condition of vascular endothelial growth factor-induced BRB breakdown, anti-recoverin antibodies could not migrate across BRB and still remained on retinal vessels without retinal cytotoxicity.
Our results suggest that high titer of intravascular anti-recoverin antibodies could not penetrate into the retina by themselves, and BRB breakdown mediated by dysregulation of tight junction might not be sufficient to allow anti-recoverin antibodies to pass through BRB.
PMCID: PMC3102823  PMID: 21655045
Anti-recoverin antibody; Blood-retinal barrier; Cancer-associated retinopathy; Intravenous administration; Retina
17.  Clusterin protects H9c2 cardiomyocytes from oxidative stress-induced apoptosis via Akt/GSK-3β signaling pathway 
Clusterin is a secretory glycoprotein, which is highly up-regulated in a variety of normal and injury tissues undergoing apoptosis including infarct region of the myocardium. Here, we report that clusterin protects H9c2 cardiomyocytes from H2O2-induced apoptosis by triggering the activation of Akt and GSK-3β. Treatment with H2O2 induces apoptosis of H9c2 cells by promoting caspase cleavage and cytochrome c release from mitochondria. However, co-treatment with clusterin reverses the induction of apoptotic signaling by H2O2, thereby recovers cell viability. The protective effect of clusterin on H2O2-induced apoptosis is impaired by PI3K inhibitor LY294002, which effectively suppresses clusterin-induced activation of Akt and GSK-3β. In addition, the protective effect of clusterin is independednt on its receptor megalin, because inhibition of megalin has no effect on clusturin-mediated Akt/GSK-3β phosphoylation and H9c2 cell viability. Collectively, these results suggest that clusterin has a role protecting cardiomyocytes from oxidative stress and the Akt/GSK-3β signaling mediates anti-apoptotic effect of clusterin.
PMCID: PMC3041938  PMID: 21270507
apoptosis; clusterin; glycogen synthase kinase 3β; myocytes, cardiac; oxidative stress; proto-oncogene proteins c-akt
18.  Benign Strictures of the Esophagus and Gastric Outlet: Interventional Management 
Korean Journal of Radiology  2010;11(5):497-506.
Benign strictures of the esophagus and gastric outlet are difficult to manage conservatively and they usually require intervention to relieve dysphagia or to treat the stricture-related complications. In this article, authors review the non-surgical options that are used to treat benign strictures of the esophagus and gastric outlet, including balloon dilation, temporary stent placement, intralesional steroid injection and incisional therapy.
PMCID: PMC2930157  PMID: 20808692
Benign esophageal strictures; Benign gastric-outlet strictures; Interventional procedure; Fluoroscopy; Endoscopy
19.  Transcatheter Arterial Chemoembolization for Hepatic Recurrence after Curative Resection of Pancreatic Adenocarcinoma 
Gut and Liver  2010;4(3):384-388.
Despite curative resection, hepatic recurrences cause a significant reduction in survival in patients with primary pancreatic adenocarcinoma. Transcatheter arterial chemoembolization (TACE) has recently been used successfully to treat primary and secondary hepatic malignancy.
Between 2003 and 2008, 15 patients underwent TACE because of hepatic recurrence after curative resection of a pancreatic adenocarcinoma. The tumor response was evaluated based on computed tomography scans after TACE. The overall duration of patient survival was measured.
After TACE, a radiographically evident response occurred in six patients whose tumors demonstrated a tumor blush on angiography. Four patients demonstrated stabilization of a hypovascular mass. The remaining five patients demonstrated continued progression of hypovascular hepatic lesions. The median survival periods from the time of diagnosis and from the time of initial TACE were 9.6 and 7.5 months, respectively.
TACE may represent a viable therapeutic modality in patients with hepatic recurrence after curative resection of pancreatic adenocarcinoma.
PMCID: PMC2956353  PMID: 20981218
Pancreatic adenocarcinoma; Transcatheter arterial chemoembolization; Liver
20.  Embolotherapy for Pulmonary Arteriovenous Malformations in Patients without Hereditary Hemorrhagic Telangiectasia 
Korean Journal of Radiology  2010;11(3):312-319.
To evaluate the clinical and radiological outcomes of transcatheter embolotherapy for treating sporadic pulmonary arteriovenous malformations (PAVMs) that were not associated with hereditary hemorrhagic telangiectasia.
Materials and Methods
Between January 2001 and June 2008, thirty-five sporadic PAVMs were detected in 23 patients. The clinical follow up consisted of assessing the changes of the signs and symptoms of the PAVMs, and radiological evaluation with chest radiographs or chest CT scans.
The lower lung regions (63%) and peripheral locations (86%) were the common locations of the PAVMs. Thirty-four PAVMs (97%) had simple architecture (one arterial feeder within a single pulmonary segment). Technical success was achieved in 33 PAVMs (94%); two cases of technical failure were due to catheterization failure (n = 1) and too large a feeding artery (17 mm) that disabled embolotherapy (n = 1). Coils and Amplatz vascular plugs were used in 30 and three PAVMs, respectively. Inadvertent placement of one coil (n = 1) and pulmonary infarction (n = 1) occurred, but no relevant symptoms developed. For the 13 patients with available data, the mean arterial O2 saturation changed significantly from 92% to 98%. Complete or near-complete involution of the sac was observed in 30 of the 33 embolized PAVMs (91%). In these 33 embolized PAVMs, the mean sac diameter significantly decreased from 17.83 mm to 0.68 mm.
Sporadic PAVMs are mostly the simple type with predominance in the lower lobe and peripheral locations. Transcatheter embolotherapy with coils or Amplatz vascular plugs is a safe and effective treatment for sporadic PAVMs and this provides excellent functional and radiological improvement.
PMCID: PMC2864858  PMID: 20461185
Pulmonary arteriovenous malformation; Hereditary hemorrhagic telangiectasia; Embolotherapy; Amplatz vascular plug
21.  Interventional Management of Esophagorespiratory Fistula 
Korean Journal of Radiology  2010;11(2):133-140.
An esophagorespiratory fistula (ERF) is an often fatal consequence of esophageal or bronchogenic carcinomas. The preferred treatment is placement of esophageal and/or airway stents. Stent placement must be performed as quickly as possible since patients with ERFs are at a high risk for aspiration pneumonia. In this review, choice of stents and stenting area, fistula reopening and its management, and the long-term outcome in the interventional management of malignant ERFs are considered. Lastly, a review of esophagopulmonary fistulas will also be provided.
PMCID: PMC2827775  PMID: 20191059
Interventional technique; Esophagorespiratory fistula; Esophagopleural fistula
22.  Differential Expression of Stem Cell Markers and Vascular Endothelial Growth Factor in Human Retinoblastoma Tissue 
To investigate the relationship between vascular endothelial growth factor (VEGF) and the cancer stem cell-vascular niche complex in human retinoblastoma tissue.
Six human retinoblastoma specimens primarily enucleated for Reese-Ellsworth classification stage 5a were stained to detect cancer stem cell markers, including ABCG2 for the stem cell marker and MCM2 for the neural stem cell marker, as well as to detect VEGF for the angiogenic cytokine. Using immunofluorescence, the expression of these proteins was analyzed, and their relative locations noted.
In non-neoplastic retina of tumor-bearing eyes, ABCG2 and MCM2 were sporadically expressed in the ganglion cell layer and the inner nuclear layer, whereas VEGF was sporadically expressed in inner retina where retinal vessels are abundantly distributed. In the tumor, ABCG2 was strongly expressed out of Wintersteiner rosettes, whereas MCM2 and VEGF were strongly stained in the rosettes. Interestingly, the outer portion of the rosettes was positive for MCM2, and the inner portion of the rosettes was positive for VEGF.
Our data demonstrated that MCM2 and VEGF are strongly expressed in the rosettes of the tumor, which were far from the area of ABCG2-positive cells. Although VEGF might not directly contribute to the cancer stem cell-vascular niche complex, it could play some role in the differentiation of tumor cells to build up the rosettes.
PMCID: PMC2817821  PMID: 20157412
Biological tumor markers; Neoplastic stem cells; Retinoblastoma; Vascular endothelial growth factors
23.  Angiographically Negative Acute Arterial Upper and Lower Gastrointestinal Bleeding: Incidence, Predictive Factors, and Clinical Outcomes 
Korean Journal of Radiology  2009;10(4):384-390.
To evaluate the incidence, predictive factors, and clinical outcomes of angiographically negative acute arterial upper and lower gastrointestinal (GI) bleeding.
Materials and Methods
From 2001 to 2008, 143 consecutive patients who underwent an angiography for acute arterial upper or lower GI bleeding were examined.
The angiographies revealed a negative bleeding focus in 75 of 143 (52%) patients. The incidence of an angiographically negative outcome was significantly higher in patients with a stable hemodynamic status (p < 0.001), or in patients with lower GI bleeding (p = 0.032). A follow-up of the 75 patients (range: 0-72 months, mean: 8 ± 14 months) revealed that 60 of the 75 (80%) patients with a negative bleeding focus underwent conservative management only, and acute bleeding was controlled without rebleeding. Three of the 75 (4%) patients underwent exploratory surgery due to prolonged bleeding; however, no bleeding focus was detected. Rebleeding occurred in 12 of 75 (16%) patients. Of these, six patients experienced massive rebleeding and died of disseminated intravascular coagulation within four to nine hours after the rebleeding episode. Four of the 16 patients underwent a repeat angiography and the two remaining patients underwent a surgical intervention to control the bleeding.
Angiographically negative results are relatively common in patients with acute GI bleeding, especially in patients with a stable hemodynamic status or lower GI bleeding. Most patients with a negative bleeding focus have experienced spontaneous resolution of their condition.
PMCID: PMC2702048  PMID: 19568467
Upper gastrointestinal bleeding; Lower gastrointestinal bleeding; Angiography
24.  Shank 2 expression coincides with neuronal differentiation in the developing retina 
Experimental & Molecular Medicine  2009;41(4):236-242.
The retinal activity for vision requires a precise synaptic connectivity. Shank proteins at postsynaptic sites of excitatory synapses play roles in signal transmission into the postsynaptic neuron. However, the correlation of Shank 2 expression with neuronal differentiation in the developing retina remains to be elucidated regardless of previous evidences of Shank 2 expression in retina. Herein, we demonstrated that with progression of development, Shank 2 is initially detected in the inner plexiform layer at P2, and then intensively detected in inner plexiform layer, outer plexiform layer, and ganglion cell layer at P14, which was closely colocalized to the neurofilament expression. Shank 2 was, however, not colocalized with glial fibrillary acidic protein. Shank 2 expression was increased in the differentiated retinoblastoma cells, which was mediated by ERK 1/2 activation. Moreover, Shank 2 expression was colocalized with neurofilament at the dendritic region of cells. In conclusion, our data suggests that Shank 2 is expressed in the neurons of the developing retina and could play a critical role in the neuronal differentiation of the developing retina.
PMCID: PMC2679234  PMID: 19299912
cell differentiation; extracellular signal-regulated MAP kinases; neurons; retina; SHANK 2 protein, human
25.  Decursin inhibits retinal neovascularization via suppression of VEGFR-2 activation 
Molecular Vision  2009;15:1868-1875.
Pathologic angiogenesis in the retina leads to the catastrophic loss of vision. Retinopathy of prematurity (ROP), a vasoproliferative retinopathy, is a leading cause of blindness in children. We evaluated the inhibitory effect of decursin on retinal neovascularization.
Anti-angiogenic activity of decursin was evaluated by vascular endothelial growth factor (VEGF)-induced proliferation, migration, and in vitro tube formation assay of human retinal microvascular endothelial cells (HRMECs). We also used western blot analysis to assess inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) phosphorylation by decursin. After intravitreal injection of decursin in a mouse model of ROP, retinal neovascularization was examined by fluorescence angiography and vessel counting in cross-sections. The toxicity of decursin was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HRMECs as well as histologic and immunohistochemistry examination for glial fibrillary acidic protein in the retina.
Decursin significantly inhibited VEGF-induced proliferation, migration, and the formation of capillary-like networks of retinal endothelial cells in a dose-dependent manner. Decursin inhibited VEGF-induced phosphorylation of VEGFR-2, blocking the VEGFR-2 signaling pathway. When intravitreously injected, decursin dramatically suppressed retinal neovascularization in a mouse model of ROP. Even in a high concentration, decursin never induced any structural or inflammatory changes to cells in retinal or vitreous layers. Moreover, the upregulation of glial fibrillary acidic protein expression was not detected in Mueller cells.
Our data suggest that decursin may be a potent anti-angiogenic agent targeting the VEGFR-2 signaling pathway, which significantly inhibits retinal neovascularization without retinal toxicity and may be applicable in various other vasoproliferative retinopathies as well.
PMCID: PMC2743803  PMID: 19756180

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