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C-H Yoon,
M-J Kim,
R-K Kim,
E-J Lim,
K-S Choi,
S An,
S-G Hwang, S-G Kang,
Y Suh,
M-J Park,
S-J Lee
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ABSTRACT: Uncovering the mechanisms that govern the maintenance of stem-like cancer cells is critical for developing therapeutic strategies for targeting these cells. Constitutive activation of c-Jun N-terminal kinase (JNK) has been reported in gliomas and correlates with histological grade. Here, we found that JNK signaling is crucial for the maintenance of 'stemness' in glioma cells. Sphere-cultured glioma cells showed more phosphorylation of JNK compared with serum-containing monolayer cultures. Importantly, blockade of JNK signaling with SP600125 or small interfering RNAs targeting JNK1 or JNK2 significantly reduced the CD133(+)/Nestin(+) population and suppressed sphere formation, colony formation in soft agar, and expression of stem cell markers in sphere-cultured glioma cells. Intriguingly, sphere-cultured glioma cells exhibited enhanced expression of Notch-2, but not Notch-1, -3 or -4, and JNK inhibition almost completely abrogated this increase. Blocking the phosphoinoside 3-kinase (PI3K)/Akt pathway with LY294002 or si-Akt also suppressed the self-renewal of sphere-cultured glioma cells. PI3K, but not Akt, had a role as an upstream kinase in JNK1/2 activation. In addition, treatment with si-JNK greatly increased etoposide- and ionizing radiation (IR)-induced cell death in glioma spheres. Consistent with glioma cell lines, glioma stem-like cells isolated from primary patient glioma cells also had a higher activity of JNK and Notch-2 expression. Importantly, inhibition of JNK2 led to a decrease of Notch-2 expression and suppressed the CD133(+)/Nestin(+) cell population in patient-derived primary glioma cells. Finally, downregulation of JNK2 almost completely suppressed intracranial tumor formation by glioma cells in nude mice. Taken together, these data demonstrate that JNK signaling is crucial for the maintenance of self-renewal and tumorigenicity of glioma stem-like cells and drug/IR resistance, and can be considered a promising target for eliminating stem-like cancer cells in gliomas.Oncogene advance online publication, 16 January 2012; doi:10.1038/onc.2011.634.
Oncogene 01/2012; · 6.37 Impact Factor
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ABSTRACT: IV administration of tPA is accepted as a standard treatment for acute cerebral ischemia, but the clinical outcomes cannot be guaranteed in patients who are not recanalized after IV-tPA and in those who are not eligible for IV-tPA. In this study, outcomes from groups of patients treated with additional IA thrombolytic therapy with the use or omission of IV-tPA administration were compared.
IA thrombolytic therapy (thrombolytic agents combined with mechanical intervention) was attempted in those patients who were not eligible for IV-tPA and who showed continuous major vessel occlusion after IV-tPA. Sixty-three patients were divided into 2 groups: a tPA group (n = 29, IA thrombolysis after IV-tPA) and a non-tPA group (n = 34, IA thrombolysis without IV-tPA). These groups were subdivided according to match or mismatch DWI/PWI after MR imaging. Treatment results were compared by recanalization rate, clinical outcome, mortality, and ICH rate.
The recanalization rate was 79.3% in the tPA group and 55.9% in the non-tPA group (χ(2) test, P < .05). Subgroup analysis between DWI/PWI mismatch in the tPA group and DWI/PWI mismatch in the non-tPA group also showed no statistical difference in recanalization rate, favorable clinical outcome, and mortality (χ(2) test, P > .05), but the significant ICH rate was high in the tPA group (χ(2) test, P < .05).
Additional IA thrombolytic treatment after full-dose IV-tPA administration might be an acceptable treatment option for patients with DWI/PWI mismatch.
American Journal of Neuroradiology 09/2010; 31(8):1536-40. · 2.93 Impact Factor
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ABSTRACT: Most previous reports indicate that traditional bilateral kyphoplasty improves patient function and restores height of collapsed vertebral bodies, but limited data about the effects of unilateral kyphoplasty on clinical and radiological outcome are available.
One hundred five patients were treated by unilateral kyphoplasty between January 2004 and December 2006. These patients underwent 105 operations to treat 132 vertebral compression fractures between T8 and L5. Sagittal alignment was analyzed from standing radiographs. Clinical outcomes were determined by comparison of preoperative and postoperative data from patient-reported index (visual analogue pain scale score). Radiographs were assessed as to percent vertebral collapse, vertebral height restoration and local kyphosis correction.
Mean length of follow-up was 15.3 months (range 3-36 months); improved height 2.3 and 4.0 mm in the anterior and medial columns, respectively (P > 0.05); Cobb angle increased 3.0 degrees (P < 0.05), visual analogue pain scale score improved from 8.7 +/- 1.4 before surgery to 2.3 +/- 0.9 (P < 0.05); no adverse medical or procedural complications; 6.8% (9/132) cement leakage rate.
Unilateral transpedicular kyphoplasty improves physical function, reduces pain, and may correct kyphotic deformity associated with vertebral compression fractures. This result shows comparable to traditional bilateral kyphoplasty procedure.
Acta neurochirurgica. Supplement 01/2008; 101:157-60.
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ABSTRACT: The authors used a separating stent-graft to treat Stanford type B aortic dissection. The separating stent-graft consists of two stents: a stent-graft and an inner bare stent. The separating stent-graft has three parts: a proximal stent, a graft made of synthetic polyester textile fiber, and a distal stent. A 12-F introducing sheath was used. After the separating stent-graft was placed, false-lumen thrombosis was evident in all six patients during a follow-up period of 206 days. The major advantages of this technique are that a cutdown and blood pressure control are not required.
Radiology 09/2001; 220(2):533-9. · 5.73 Impact Factor
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ABSTRACT: To investigate the therapeutic potential of Mitomycin-C (MMC) in the management of proliferative vitreoretinopathy, the antiproliferative effect of MMC on cultured human retinal pigment epithelial (RPE) cells were investigated in vitro.
Drug sensitivities of cultured human RPE cells to MMC were determined using the tetrazolium dye assay. In order to detect the presence of apoptosis, DNA fragmentation was assessed by DAPI staining, and TdT-dUTP nick-end labeling (TUNEL) assay. The relative amount of DNA fragmentation was quantified by flow cytometric analysis. To analyze the cell cycle response of RPE cells to MMC, flow cytometric analysis of propidium iodide stained nuclei was performed. The levels of proteins related to DNA damage in the RPE cells were then determined by Western blot analysis.
MMC inhibited cell proliferation in a dose-dependent manner. The majority of RPE cells following treatment with 10 microg/ml of MMC exhibited fragmented nuclei as observed by DAPI staining and TUNEL assay. Cell cycle analysis demonstrated an accumulation of cells arrested in S and G2/M phase following treatment with 1 microg/ml of MMC. At 10 microg/ml of MMC, a dramatic increase of the cell population in the sub G1 peak, which can be considered a marker of cell death by apoptosis, was observed by flow cytometry. Western blot analysis of p53 and p21 revealed a gradual increase in the level of these proteins when RPE cells were exposed to increasing concentrations of MMC.
This study demonstrated that the response of RPE cells to MMC was bi-directional: 1) partial arrest of the cell cycle at S, G2/M phase, and 2) induction of apoptotic cell death.
Current Eye Research 04/2001; 22(3):174-81. · 1.28 Impact Factor
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ABSTRACT: To investigate the safety and clinical effectiveness of covered retrievable expandable nitinol stents in 25 patients with a benign esophageal stricture.
Under fluoroscopic guidance, covered retrievable expandable nitinol stents were placed in 25 patients with a benign esophageal stricture and were removed with a retrieval hook 1-8 weeks later.
Stent placement was successful in all patients, with no procedural complications. After stent placement, all patients could ingest solid food. The stents were successfully removed from all but two patients. One patient passed the stent via the rectum, and the other regurgitated a high cervical stent. After stent removal, one patient developed a small esophagobronchial fistula, which spontaneously sealed within 1 week of stent removal. After stent removal or migration, all patients could ingest solid food. During follow-up (mean, 13 months; range, 2-25 months) after stent removal or migration, 12 patients maintained their improvement in dysphagia and needed no further treatment. Thirteen patients with recurrence were treated by means of repeat balloon dilation.
Use of retrievable expandable nitinol stents seems to be a safe and effective method of treatment in selected patients with benign esophageal strictures.
Radiology 12/2000; 217(2):551-7. · 5.73 Impact Factor
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ABSTRACT: To investigate the technical feasibility and clinical effectiveness of a polyurethane-covered expandable nitinol stent in the treatment of malignant gastroduodenal obstructions.
The stent was constructed in-house by weaving a single thread of 0.2-mm nitinol wire in a tubular configuration and was covered with polyurethane solution by means of a dipping method. With fluoroscopic guidance, the stent was placed in 19 consecutive patients with malignant gastric outlet obstruction (n = 15) or duodenal obstruction (n = 4). All patients had severe nausea and recurrent vomiting, and their obstructions were inoperable.
Stent placement was technically successful in all but one patient. After stent placement, symptoms improved in all but one patient, who had another stenosis at the proximal jejunum. One patient with stent placement in the second portion of the duodenum became jaundiced. During the mean follow-up of 11 weeks, stent migration occurred in five patients 1-4 days after the procedure. All patients with stent migration were treated by means of placing a second, uncovered nitinol stent. Two of these five patients showed recurrence of stricture because of tumor ingrowth; they underwent coaxial placement of a third, covered nitinol stent with good results.
Placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible and effective for palliative treatment of inoperable malignant gastroduodenal obstructions. Stent migration, however, is problematic and requires further investigation.
Radiology 10/2000; 216(3):758-63. · 5.73 Impact Factor
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ABSTRACT: In a model of focal cerebral ischaemia, enlargement of ischaemic tissue by ischaemic brain oedema is one of the major problems in the measurement of infarction volume. To minimize an error of this overestimation, several methods have been proposed. However, there has been no attempt to compare these methods to elucidate their eligibility in the measurement of ischaemic area. The authors used three different morphometric analyses in the measurement of infarction volume to assess the antiischaemic affects of a competitive NMDA antagonist, D-CPPene in MCA occlusion model of the rat: a direct measurement, the Swanson's method, and a measurement using a diagram. Post-occlusion treatment of D-CPPene (4.5 mg/kg, i.v. +3 mg/kg/h, i.v.) produced reduction of infarction volume to about 40% compared to the control (P < 0.05). The volume of infarction determined by the direct measurement was much larger than that by Swanson's or diagram method (P < 0.05), about 70% larger in the control and by two times in the treated. However, there was no significant difference in the measured volume between the Swanson's and diagram methods. The protection rate, which was calculated as % = (infarct volume of the control--that of the treated/infarct volume of the control) x 100%, was larger in the Swanson's and diagram methods than in the direct measurement. In conclusion, it is confirmed that the direct measurement at the peak time of ischaemic brain oedema brings about not only an overestimation of infarction volume but lower protection rate also, compared to the methods designed to minimize the overestimation. Our results also demonstrate the diagram method is useful in reducing overestimation of infarct volume that may be caused by ischaemic brain oedema, though this method was not designed for the purpose of avoiding oedema at first.
Acta neurochirurgica. Supplement 02/2000; 76:269-71.
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ABSTRACT: To investigate the effect of illumination on visual acuity and visual field in eyes with multifocal intraocular lens (IOL), the near and far visual acuity of the eyes with multifocal implants were compared to those of the eyes with monofocal implants in the diminished illumination, and the visual fields of two groups were also compared by the different target size and intensity. The near and far visual acuity of the eyes with multifocal implants were significantly decreased as compared to those of the eyes with monofocal implants under diminished illumination, and the visual field of the multifocal implanted eyes also significantly decreased as compared to that of the monofocal implanted eyes by the reduction of spot size and intensity. From the above results, it is assumed that the bifocal separation of incident light to two simultaneous focal points in the multifocal implants causes more decreased visual acuity and narrower visual field in the diminished illumination as compared to that of the eyes with monofocal implants.
Korean Journal of Ophthalmology 01/1995; 8(2):72-6.
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ABSTRACT: Pheochromocytoma of the urinary bladder is an unusual tumor that typically presents with hypertensive crises related to micturition. We report here an unusual case of bladder pheochromocytoma that was treated by robotic-assisted laparoscopic partial cystectomy. A 35-year-old male patient presented with headache and hypertension related to micturition. The patient, who had a 3.5 × 4 cm solitary bladder tumor in the bladder dome, underwent robot-assisted partial cystectomy. The whole procedure was successfully performed using the robot without conversion to open surgery. The total operative time was 120 min and the estimated blood loss was 30 ml.
Urologia Internationalis 08/1970; 87(2):241-244. · 0.99 Impact Factor
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ABSTRACT: In order to completely fill a 41 nm trench pattern with Cu using electroless deposition (ELD), we introduced a method of forming Au catalytic layer based on a self-assembled monolayer (SAM) of aminopropyltriethoxy silane molecules as a coupling agent. The nano-sized Au catalyst layer was deposited on Ta/SiO2/Si substrate through electrostatic interactions between the positively charged amine-SAM layer on the substrate and the negatively charged Au nanoparticles. The interspacing among Au nanoparticles was adjusted by controlling the pH in order to obtain a close-packed catalytic layer. The size of deposited Au nanoparticle catalyst was approximately 4 nm and uniform distribution was obtained at pH 6. After Au catalysts were formed on the amine-coated substrate at pH 6, the substrate soaked in electroless bath with polyethylene glycol as an inhibiting additive. Cross-section views showed that the Cu completely filled the pattern without voids or seams. The electrical resistivity of the electrolessly deposited Cu films with 41 nm thickness was determined to be 2.6 μΩ cm after the annealing process; a this resistivity is 1.4 times lower than recommended by the International Technology Roadmap for Semiconductors. Therefore, the SAM modified ELD is a promising method for filling a 41 nm trench pattern with Cu.
Materials Chemistry and Physics 123:401-406. · 2.23 Impact Factor
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ABSTRACT: To overcome the limitation of the sputtered Cu seed layer in electroplating of Cu interconnects imposed by the shadow effect, a new method for depositing a Cu seed layer on a 41 nm trench pattern based on combination of electroless plating (ELP) and electron-beam (E-Beam) evaporation was developed. A Cu seed layer formed by ELP alone was too thin to be used for electroplating due to its high resistivity. To solve this problem, an additional Cu layer was deposited on top of the trench by E-Beam evaporator to enhance the electrical conductivity of the Cu seed layer. The electrical resistivity of the resulting Cu layer was reduced to 4.8 μΩ cm, which was sufficient for the conductive seed layer for electroplating the 41 nm trench pattern. The gap-filling capability also improved and there were no voids or seams in the 41 nm trench pattern. The proposed method can be an effective solution for fabrication of a conductive seed layer to fill a 41 nm trench pattern by electroplating.
Applied Surface Science 256(8):2649-2653. · 2.10 Impact Factor
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ABSTRACT: The layered Li[Ni1/3Co1/3Mn1/3]O2 materials were synthesized by a spray pyrolysis method using citric acid as a polymeric agent. The Li[Ni1/3Co1/3Mn1/3]O2 powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and high-resolution transmission electron microscopy (TEM). The discharge capacity increases linearly with the increase of the upper cut-off voltage limit. TEM analysis showed that particles in the as-prepared powder possessed a polycrystalline structure. During cycling, the particle structure is mostly preserved although some surface grains on the polycrystalline particle became separated and transformed to the spinel phase.
Electrochimica Acta.
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ABSTRACT: Balloon dilation of the lacrimal canaliculi has been considered contraindicated because of possible damage to the canaliculi. The purpose of this study was to assess the safety and effectiveness of balloon dilation in treatment of obstruction of the lacrimal canaliculus.
Fluoroscopically guided balloon dilation was performed in 26 eyes of 21 consecutive patients with epiphora due to lacrimal canalicular obstruction confirmed at dacryocystography. Nine of 26 eyes had complete obstruction and 17 eyes had incomplete obstruction.
Technical failure occurred in one eye. Only one acute complication (punctal slitting) and no late complications occurred. At 7 days after balloon dilation, 14 of 17 eyes (82%) with incomplete obstruction and five of nine eyes (56%) with complete obstruction showed complete or partial resolution of epiphora with patency of the lacrimal drainage system. At 6-month follow-up, that improvement was maintained in seven of 17 eyes (41%) with incomplete obstruction and three of nine eyes (33%) with complete obstruction.
Although the 6-month recurrence rate is rather high, balloon dilation seems to be safe and valuable as an initial therapy for patients with obstruction of the lacrimal canaliculus.
Journal of Vascular and Interventional Radiology 7(6):929-34. · 2.08 Impact Factor
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ABSTRACT: To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane.
Using a peristaltic pump at a constant rate of 1 ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice.
Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing.
When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.
Korean Journal of Radiology 2(2):75-9. · 1.54 Impact Factor
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ABSTRACT: The effect of Zr addition to Pt-modified aluminide coatings was investigated. Zr coatings on Pt-modified aluminide coatings were deposited by EB-PVD and heat treatments were conducted. SEM analysis indicated that Zr was situated at the surface and grain boundary near the surface as an agglomerated form of the NiAl–Zr alloy, which affected the growth rate of the thermally grown oxide during cyclic oxidation. Also, the interface and surface roughnesses of Zr-added Pt-modified aluminide coatings were smaller than that of the Pt-modified aluminide coating. Also, phase stabilities of Zr-added Pt-modified aluminide coating were enhanced as compared with the Pt-modified aluminide coating. Because Zr-added Pt-modified aluminide coatings had resistance to spallation of TGO caused by Zr-rich oxide pegs, they showed better resistance to cyclic oxidation than Pt-modified aluminide coating without Zr addition.
Intermetallics.
