• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.382-382
• /
• 2012

Nanostructures have a larger surface/volume ratio as well as unique mechanical, physical, chemical properties compared to existing bulk materials. Materials for biomedical implants require a good biocompatibility to provide a rapid recovery following surgical procedure and a stabilization of the region where the implants have been inserted. The biocompatibility is evaluated by the degree of the interaction between the implant materials and the cells around the implants. Recent researches on this topic focus on utilizing the characteristics of the nanostructures to improve the biocompatibility. Several studies suggest that the degree of the interaction is varied by the relative size of the nanostructures and cells, and the morphology of the surface of the implant [1, 2]. In this paper, we fabricate the nanowires on the Ti substrate for better biocompatible implants and other biomedical applications such as artificial internal organ, tissue engineered biomaterials, or implantable nano-medical devices. Nanowires are fabricated with two methods: first, nanowire arrays are patterned on the surface using e-beam lithography. Then, the nanowires are further defined with deep reactive ion etching (RIE). The other method is self-assembly based on vapor-liquid-solid (VLS) mechanism using Sn as metal-catalyst. Sn nanoparticle solutions are used in various concentrations to fabricate the nanowires with different pitches. Fabricated nanowries are characterized using scanning electron microscopy (SEM), x-ray diffraction (XRD), and high resolution transmission electron microscopy (TEM). Tthe biocompatibility of the nanowires will further be investigated.

• Childhood Kidney Diseases
• /
• v.21 no.1
• /
• pp.1-7
• /
• 2017

Mitogen-activated protein kinases (MAPKs) play important roles in various cellular functions including proliferation, differentiation, and apoptosis. We showed that MAPKs are developmentally regulated in the rat kidney. p38 MAPK (p38) and extracellular signal-regulated kinase (ERK) were strongly expressed in the fetal kidney, whereas c-Jun N-terminal kinase (JNK) was detected predominantly in the adult kidney. The inhibition of p38 or ERK in organ culture resulted in reduced nephron formation with or without reduced kidney size. On the other hand, persistent fetal expression pattern of MAPKs, i.e., upregulation of p38 and ERK and downregulation of JNK, was observed in the cyst epithelium of human renal dysplasia, ovine fetal obstructive uropathy, and pcy mice, a model of polycystic kidney disease. Furthermore, activated p38 and ERK induced by cyclic stretch mediated proliferation and $TGF-{\beta}1$ expression in ureteric bud cells, probably leading to cyst formation and dysplastic changes. Inhibition of ERK slowed the disease progression in pcy mice. Finally, ERK and p38 were inactivated in the early embryonic kidney subjected to maternal nutrient restriction, characterized by reduced ureteric branching and nephron number. Thus, MAPKs mediate the development of normal and diseased kidney. Their modulation may result in novel therapeutic strategies against developmental abnormalities of the kidney.

• Radiation Oncology Journal
• /
• v.35 no.3
• /
• pp.274-280
• /
• 2017

Purpose: To see the gross tumor volume (GTV) dependency according to the phase selection and reconstruction methods, we measured and analyzed the changes of tumor volume and motion at each phase in 20 cases with lung cancer patients who underwent image-guided radiotherapy. Materials and Methods: We retrospectively analyzed four-dimensional computed tomography (4D-CT) images in 20 cases of 19 patients who underwent image-guided radiotherapy. The 4D-CT images were reconstructed by the maximum intensity projection (MIP) and the minimum intensity projection (Min-IP) method after sorting phase as 40%-60%, 30%-70%, and 0%-90%. We analyzed the relationship between the range of motion and the change of GTV according to the reconstruction method. Results: The motion ranges of GTVs are statistically significant only for the tumor motion in craniocaudal direction. The discrepancies of GTV volume and motion between MIP and Min-IP increased rapidly as the wider ranges of duty cycles are selected. Conclusion: As narrow as possible duty cycle such as 40%-60% and MIP reconstruction was suitable for lung cancer if the respiration was stable. Selecting the reconstruction methods and duty cycle is important for small size and for large motion range tumors.

• Journal of Chest Surgery
• /
• v.16 no.1
• /
• pp.161-166
• /
• 1983

The origin of hamartoma from the Greek words for "error" and "tumor" is credited to Albrecht who in 1904 described a disorganized arrangement of tissues normally present in an organ and applied also to tumors found in many organs other than the lung. The hamartoma is the most common benign tumor of the lung and revealed accidentally as asymptomatic coin lesion on routine chest X-ray, but the incidence is very low and especially endobronchial origin extremely low. We have been successful surgical experienced one case of a 36-year-old female having endobronchial hamartoma, 4x2.Sx2 cm in size and located at right main bronchial lumen near the carina, which consists of a hard, nodular surfaced mass and adhered to the cartilaginous portion of the right upper lobe bronchus by dense fibrous band and migrate to trachea on expiration or coughing. This case was not suspected by chest X-ray or bronchogram and confirmed bronchoscopy with biopsy. Right pneumonectomy was inevitable because of bronchiectatic change of right bronchus due to tumor obstruction. She was discharged with relatively good general condition on 21 days postoperatively.

• Journal of Computing Science and Engineering
• /
• v.6 no.3
• /
• pp.219-226
• /
• 2012

Recently, shape analysis of human organs has achieved much attention, owing to its potential to localize structural abnormalities. For a group-wise shape analysis, it is important to accurately restore the shape of a target structure in each subject and to build the inter-subject shape correspondences. To accomplish this, we propose a shape modeling method based on the Laplacian deformation framework. We deform a template model of a target structure in the segmented images while restoring subject-specific shape features by using Laplacian surface representation. In order to build the inter-subject shape correspondences, we implemented the progressive weighting scheme for adaptively controlling the rigidity parameter of the deformable model. This weighting scheme helps to preserve the relative distance between each point in the template model as much as possible during model deformation. This area-preserving deformation allows each point of the template model to be located at an anatomically consistent position in the target structure. Another advantage of our method is its application to human organs of non-spherical topology. We present the experiments for evaluating the robustness of shape modeling against large variations in shape and size with the synthetic sets of the second cervical vertebrae (C2), which has a complex shape with holes.

• Macromolecular Research
• /
• v.10 no.2
• /
• pp.67-74
• /
• 2002

New immunoprotecting membranes were prepared by spin coating the amphiphilic random multiblock copolymers of poly(ethylene glycol) (PEG) and poly(tetramethylene ether glycol) (PTMEG) or poly(dimethyl siloxane) (PDMS) on porous Durapore(R) membrane. The copolymer coating was intended to make a biocompatible, immunoprotecting diffusional barrier and the supporting porous substrate was for mechanical stability and processability. By filling Durapore(R) membrane pores with water, the penetration of coating solution into the pores was minimized during the spin coating process. A single coating process produced a completely covered thin surface layer (~1 ${\mu}{\textrm}{m}$ in thickness) on the porous substrate membrane. The permselectivity of the coated layer was influenced by PEG block length, polymer composition, and thickness of the coating layer. A composite membrane with the coating layer prepared with PEG 2 K/PTMEG 2 K block copolymer showed that its molecular weight cut-of fat any 40 based on dextran was close to the molecular size of IgG (Mw = 150 kDa). However, IgG permeation was detected from protein permeation test, while glucose oxidase (Mw = 186 kDa) was not permeable through the coated membrane.

• BMB Reports
• /
• v.47 no.10
• /
• pp.540-545
• /
• 2014

Balanced cell growth is crucial in animal development as well as tissue homeostasis. Concerted cross-regulation of multiple signaling pathways is essential for those purposes, and the dysregulation of signaling may lead to a variety of human diseases such as cancer. The time-honored Wnt/${\beta}$-catenin and recently identified Hippo signaling pathways are evolutionarily conserved in both Drosophila and mammals, and are generally considered as having positive and negative roles in cell proliferation, respectively. While most mainstream regulators of the Wnt/${\beta}$-catenin signaling pathway have been fairly well identified, the regulators of the Hippo pathway need to be more defined. The Hippo pathway controls organ size primarily by regulating cell contact inhibition. Recently, several cross-regulations occurring between the Wnt/${\beta}$-catenin and Hippo signaling pathways were determined through biochemical and genetic approaches. In the present mini-review, we mainly discuss the signal transduction mechanism of the Hippo signaling pathway, along with cross-talk between the regulators of the Wnt/${\beta}$-catenin and Hippo signaling pathways.

• Archives of Reconstructive Microsurgery
• /
• v.23 no.2
• /
• pp.89-92
• /
• 2014

An 8-year-old girl diagnosed with dilated cardiomyopathy and Russell-Silver syndrome was admitted to our pediatric intensive care unit due to low cardiac output and multiple-organ dysfunction. The patient was placed on the heart transplant waiting list and extracorporeal membrane oxygenation was performed as a bridge to transplantation. After 17 days, heart transplantation was performed. The donor was a 46-year-old female (weight, 50 kg; height, 150 cm). The donor:recipient weight ratio was 3.37:1. Because the dimension and volume of the recipient's thoracic cage were insufficient, the sternum could not be closed. Nine days after transplantation, the patient underwent delayed sternal closure. To obtain adequate space, we left the sternum 4.5 cm apart from each margin using four transverse titanium plates. A transverse rectus abdominis musculocutaneous flap was chosen to cover the wound. Due to the shortage of donors, a size-mismatched pediatric heart transplantation is sometimes unavoidable. Closure of the opened sternum of a transplant recipient can be challenging. Sternal reconstruction after an extremely oversized heart transplantation with transverse titanium plate fixation and a musculocutaneous flap can effectively achieve sternal closure and stability.

• Journal of Trauma and Injury
• /
• v.30 no.4
• /
• pp.231-234
• /
• 2017

Extrahepatic bile duct injury is commonly associated with hepatic, duodenal, or pancreatic injuries, and isolated extrahepatic bile duct injury is rare. We report a patient who presented with an isolated extrahepatic bile duct injury after blunt trauma. A 50-year-old man was referred to our hospital after having suffered a fall down injury. His laboratory findings showed hyperbiliribinemia with elevated aspartate aminotransferase and alanine aminotransferase level. Initial abdominal computed tomography (CT) showed a mild degree of hemoperitoneum without evidence of abdominal solid organ injury. On the 3rd day of hospitalization, the patient complained of dyspnea and severe abdominal discomfort. Follow-up abdominal CT showed no significant interval change. Owing to the patient's condition, Emergency laparotomy revealed a large amount of bile-containing fluid collection and about 1 cm in size laceration on the left lateral side of the common hepatic duct. Primary repair of the injured bile duct with T-tube insertion was performed On postoperative day (POD) 30, endoscopic retrograde cholangiopancreatography showed minimal bile leakage and endoscopic sphincteroplasty and endoscopic retrograde biliary drainage were performed. On POD 61, the T-tube was removed and the patient was discharged.

• BMB Reports
• /
• v.50 no.6
• /
• pp.281-282
• /
• 2017

Advances in the understanding of the Hippo signaling as a key regulatory pathway of proliferation and apoptosis have provided mechanical insights for controlling organ size and tumorigenicity. Recently, much attention has been directed to the regulation of LATS1/2 (large tumor suppressor) kinases that phosphorylate YAP/TAZ, a transcriptional co-activator in the Hippo pathway, and control the level and nuclear localization of YAP/TAZ. In our recent work, we showed that deubiquitinase YOD1 stabilizes ITCH, and facilitates ITCH-mediated LATS1/2 ubiquitination and degradation, resulting in increased YAP/TAZ level. Furthermore, we found that the YOD1-ITCH-LATS1/2-YAP/TAZ signaling axis is controlled by the differential expression of miR-21 in a cell-density-dependent manner. Using a transgenic mouse model, we showed that the inducible expression of YOD1 enhances the proliferation of hepatocytes and leads to hepatomegaly in a YAP/TAZ-activity-dependent manner. Moreover, a strong correlation was observed between YOD1 and YAP expression in liver cancer patients. Overall, our data suggest that YOD1 is a novel regulator of the Hippo pathway, and thereby a potential therapeutic target for liver cancer.