Lubricant-infused directly engraved nano-microstructures for mechanically durable endoscope lens with anti-biofouling and anti-fogging properties.

While a clear operating field during endoscopy is essential for accurate diagnosis and effective surgery, fogging or biofouling of the lens can cause loss of visibility during these procedures. Conventional cleaning methods such as the use of an irrigation unit, anti-fogging surfactant, or particle-based porous coatings infused with lubricants have been used but proven insufficient to prevent loss of visibility. Herein, a mechanically robust anti-fogging and anti-biofouling endoscope lens was developed by forming a lubricant-infused directly engraved nano-/micro-structured surface (LIDENS) on the lens. This structure was directly engraved onto the lens via line-by-line ablation with a femtosecond laser. This directly engraved nano/microstructure provides LIDENS lenses with superior mechanical robustness compared to lenses with conventional particle-based coatings, enabling the maintenance of clear visibility throughout typical procedures. The LIDENS lens was chemically modified with a fluorinated self-assembled monolayer (F-SAM) followed by infusion of medical-grade perfluorocarbon lubricants. This provides the lens with high transparency (> 70%) along with superior and long-lasting repellency towards various liquids. This excellent liquid repellency was also shown to be maintained during blood dipping, spraying, and droplet condensation experiments. We believe that endoscopic lenses with the LIDENS offer excellent benefits to endoscopic surgery by securing clear visibility for stable operation.

Effect of spatial arrangement and structure of hierarchically patterned fibrous scaffolds generated by a femtosecond laser on cardiomyoblast behavior.

Biological responses on biomaterials occur either on their surface or at the interface. Therefore, surface characterization is an essential step in the fabrication of ideal biomaterials for achieving effective control of the interaction between the material surface and the biological environment. Herein, we applied femtosecond laser ablation on electrospun fibrous scaffolds to fabricate various hierarchical patterns with a focus on the alignment of cells. We investigated the simultaneously stimulated response of cardiomyoblasts based on multiple topographical cues, including scales, oriented directions, and spatial arrangements, in the fibrous scaffolds. Our results demonstrated a synergistic effect on cell behaviors of one or more structural arrangements in a homogeneous orientation, whereas antagonistic effects were observed for cells arranged on a surface with heterogeneous directions. Taken together, these results indicate that our hierarchically patterned fibrous scaffolds may be useful tools for understanding the cellular behavior on fibrous scaffolds used to mimic an extracellular matrix-like environment. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1732-1742, 2018.

Engineering an aligned endothelial monolayer on a topologically modified nanofibrous platform with a micropatterned structure produced by femtosecond laser ablation.

A monolayer of endothelial cells (ECs) aligned along the direction of blood flow plays crucial roles in the regulation of anti-thrombogenic and pro-inflammatory reactions in the blood vessel wall. Thus, many researchers have attempted to mimic the aligned structure of ECs in vascular grafts or tissue-engineered blood vessels. In the present study, we fabricated micro-groove patterned nanofibers using a femtosecond laser ablation technique to recapitulate the densely organized anisotropic architecture of the endothelial layer. Femtosecond laser ablation enabled us to generate high-resolution groove patterns (10 µm width) with 20 or 80 µm gaps on randomly oriented electrospun nanofibers. The patterned nanofibers exhibited anisotropic (transverse: 101.1 ± 4.0° and longitudinal: 123.5 ± 9.4°) water contact angles; however, the mechanical properties were consistent in both directions. The micropatterned nanofibers modulated the aligned structure or aspect ratio (20 µm: 0.23 ± 0.11 and 80 µm: 0.42 ± 0.18) of ECs along the pattern direction. In particular, the engineered aligned endothelial layer was effective in eliciting an anti-inflammatory response (approximately 50% greater than that of random or aligned nanofibers), thereby effectively preventing monocyte adhesion following activation by TNF-α treatment. Therefore, micropatterning by laser ablation can be utilized to generate high-resolution microgrooves on various substrates, thereby providing fundamental platforms for vascular tissue engineering.

Ultrathin Metal Films with Defined Topographical Structures as In Vitro Cell Culture Platforms for Unveiling Vascular Cell Behaviors.

Implanted material surfaces make direct contact with body tissues to work on its own purpose. Therefore, studies of the surface properties of implantable materials that determine cell fate are very important for successful implantation. Although numerous studies have addressed the relationship between cells and material surfaces, nonmetallic surfaces and metallic surfaces likely produce different cellular responses because of their intrinsic differences in surface energy, roughness, and chemical composition. Moreover, given the nontransparent property of metal materials, which hampers the real-time imaging of cellular behavior, a detailed cellular-level analysis at the metal-tissue interface has not been performed. In this study, metal-based cell culture platforms (MCPs) with defined microscale topographical patterns are developed using a combination of photolithography and direct current magnetron sputtering techniques. The MCPs allow to observe vascular cells on metals in real time and identify the selective regulation of human aortic smooth muscle cells and Human umbilical vein endothelial cells (HUVECs) by metallic surface topography. Additionally, atomic force microscopy, contact angles, and energy-dispersive X-ray spectroscopy analyses show that the MCPs exhibit nearly identical chemical properties with their bulk counterparts, demonstrating that MCPs can be utilized as an in vitro cell culture platform system for understanding the cellular behavior on metal substrates.

Creating Hierarchical Topographies on Fibrous Platforms Using Femtosecond Laser Ablation for Directing Myoblasts Behavior.

Developing an artificial extracellular matrix that closely mimics the native tissue microenvironment is important for use as both a cell culture platform for controlling cell fate and an in vitro model system for investigating the role of the cellular microenvironment. Electrospinning, one of the methods for fabricating structures that mimic the native ECM, is a promising technique for creating fibrous platforms. It is well-known that align or randomly distributed electrospun fibers provide cellular contact guidance in a single pattern. However, native tissues have hierarchical structures, i.e., topographies on the micro- and nanoscales, rather than a single structure. Thus, we fabricated randomly distributed nanofibrous (720 ± 80 nm in diameter) platforms via a conventional electrospinning process, and then we generated microscale grooves using a femtosecond laser ablation process to develop engineered fibrous platforms with patterned hierarchical topographies. The engineered fibrous platforms can regulate cellular adhesive morphology, proliferation, and distinct distribution of focal adhesion proteins. Furthermore, confluent myoblasts cultured on the engineered fibrous platforms revealed that the direction of myotube assembly can be controlled. These results indicate that our engineered fibrous platforms may be useful tools in investigating the roles of nano- and microscale topographies in the communication between cells and ECM.

Clinical Characteristics of Microscopic Colitis in Korea: Prospective Multicenter Study by KASID.

BACKGROUND/AIMS: Microscopic colitis (MC) encompasses collagenous and lymphocytic colitis and is characterized by chronic diarrhea. In cases of MC, colonic mucosae are macroscopically normal, and diagnostic histopathological features are observed only upon microscopic examination. We designed a prospective multicenter study to determine the clinical features, pathological distribution in the colon and prevalence of MC in Korea. METHODS: We prospectively enrolled patients having watery diarrhea no more than 3 times a day between March 2008 and February 2009. We obtained patient histories and performed colonoscopies with random biopsies at each colon segment. RESULTS: A total of 100 patients with chronic diarrhea were enrolled for a normal colonoscopy and stool exam. MC was observed in 22 patients (22%) (M:F 1.2:1; mean age, 47.5 years). Of those 22 patients, 18 had lymphocytic colitis and 4 had collagenous colitis. The entire colon was affected in only 3 cases (13.6%), the ascending colon in 6 cases (27.2%), the transverse colon in 3 cases (13.6%), and the left colon in 3 cases (13.6%). More than 2 segments were affected in 7 cases (31.8%). Nonsteroidal anti-inflammatory drug-associated MCs were observed in 4 cases (18.2%), 3 of which showed improved diarrhea symptoms following discontinuation of the medication. Frequently associated symptoms were abdominal pain and weight loss. Autoimmune diseases were observed in 4 cases (18.2%). Half of the 22 patients with MC improved with conservative care by loperamide or probiotics. CONCLUSIONS: In a prospective multicenter study of Korean patients with chronic diarrhea, the frequency of MC was found to be approximately 20%, similar to the percentage observed in Western countries. Therefore, the identification of MC is important for the adequate management of Korean patients with chronic diarrhea.

Patient factors predictive of inadequate bowel preparation using polyethylene glycol: a prospective study in Korea.

BACKGROUND: Inadequate bowel preparation is important because it can result in missed lesions, cancelled procedures, increased procedural time, and a potential increase in complication rates. This prospective study was designed to look at the quality of colon preparation using polyethylene glycol solution and evaluate potential associations between specific patient characteristics and inadequate bowel preparation. METHODS: A total of 362 patients who were compliant with preparation instructions were enrolled. All colonoscopic examinations were performed by an experienced endoscopist and the quality of the preparation was graded by the endoscopist (excellent to poor). Patient demographic and medical history information was gathered before the procedure. Possible predictors of inadequate colonic preparation were analyzed using univariate statistics and multivariate logistic regression models. RESULTS: An inadequate bowel preparation was reported in 28.2% of observed colonoscopies. In multivariate regression analysis, age greater than 60 years [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.04-7.4], a history of diabetes (OR 8.6, 95% CI 6.3-19.4), a history of appendectomy (OR 4.6, 95% CI 2.0-10.5), a history of colorectal resection (OR 7.5, 95% CI 3.4-17.6), and a history of hysterectomy (OR 3.4, 95% CI 1.1-10.4) were independent predictors of an inadequate colon preparation. CONCLUSIONS: This prospective study identified several factors that may predict inadequate polyethylene glycol preparation independent of compliance with preparation instructions and procedure starting time. This result may help to identify patients at an increased risk for inadequate bowel preparation for whom alternative preparation protocols would be beneficial.

Toothpick impaction with sigmoid colon pseudodiverticulum formation successfully treated with colonoscopy.

Foreign bodies in the colon are encountered with increasing frequency, but only sporadic reports concerning their management have appeared in the literature. While most ingested foreign bodies usually pass through the gastrointestinal tract uneventfully, sharp foreign bodies such as toothpicks infrequently cause intestinal perforation and may even result in death. We report our experience with a patient with a sigmoid colon pseudodiverticulum formation, a complication of accidental ingestion of a toothpick that was diagnosed and successfully managed colonoscopically.

Insulin therapy and colorectal adenoma risk among patients with Type 2 diabetes mellitus: a case-control study in Korea.

PURPOSE: Patients with Type 2 diabetes mellitus may be at increased colorectal adenoma and cancer risk. Moreover, chronic insulin therapy may increase the risk of colorectal cancer among patients with Type 2 diabetes mellitus. We investigated to determine whether insulin therapy might increase the risk of colorectal adenoma among clinically confirmed patients with Type 2 diabetes mellitus. METHODS: We conducted a retrospective study among patients with Type 2 diabetes mellitus who underwent total colonoscopy between January 2003 and July 2006 at Hallym University Sacred Heart Hospital. Among them (n = 325), patients with histologically confirmed colorectal adenomas (n = 100) and the same number of controls matched by age and sex were selected and analyzed. RESULTS: Adenoma cases showed significantly higher rate of chronic insulin therapy (more than 1 year) than controls (P = 0.018). In multivariate regression analysis, patients who received chronic insulin therapy had three times the risk of colorectal adenoma compared with patients who received no insulin (odds ratio, 3; 95 percent confidence interval, 1.1-8.9; P = 0.04). CONCLUSIONS: Chronic insulin therapy was associated with increased colorectal adenoma risk among Type 2 diabetes mellitus patients. This result may provide a need for more intensive colorectal cancer screening program in patients with Type 2 diabetes mellitus, especially those who receive chronic insulin therapy.

Has peptic ulcer disease changed during the past ten years in Korea? A prospective multi-center study.

BACKGROUND: The incidence of H. pylori-negative, idiopathic peptic ulcer disease (IPUD) seems to be increasing with the changing trends of PUD and H. pylori infection in some developed countries. AIM: To investigate the changing trend of PUD and the prevalence ofH. pylori infection during the last decade and the prevalence of IPUD in Korea. METHODS: We prospectively evaluated H. pylori infection and the characteristics of PUD in 895 patients with newly diagnosed PUD from September 2004 to February 2005. RESULTS: The H. pylori infection rate in PUD was 72.0% and the proportion of IPUD was 22.2%. The proportion of gastric ulcer (GU) has significantly increased (47.8% vs. 44.3%) and the proportion of duodenal ulcer (DU) has significantly decreased (38.9% vs. 44.9%) compared with ten years ago. The changing trend in the prevalence of H. pylori infection in GU and DU showed an increase in GU (66.1% vs. 73.1%, P = 0.014) and a decrease in DU (79.3% vs. 68.1%, P = 0.001). CONCLUSION: Compared with our results of ten years ago, there has been a significant change in the distribution of PUD and in the prevalence of H. pylori infection in GU and DU. Patients with IPUD are not uncommon in Korea.

Gallbladder lymphangioma: a case report and review of the literature.

Lymphangiomas are rare, benign tumors of the lymphatic system, usually present in children aged 5 years and younger. Because they are asymptomatic until the mass enlarges to cause symptoms, most lymphangiomas are diagnosed at adulthood incidentally. We experienced a case of a 60-year-old man diagnosed with a cystic lymphangioma of the gallbladder, which was successfully resected without any complication. Magnetic resonance imaging and magnetic resonance cholangiopancreatography were very helpful for the diagnosis of the cystic lesion around the gallbladder as were ultrasonography and computed tomography scan. These showed a multi-lobulated cystic mass with intact cystic duct and bile duct in the gallbladder fossa. The patient underwent an open cholecystectomy and the histological findings were consistent with a cystic lymphangioma of the gallbladder. We here report the case of cystic lymphangioma of the gallbladder with a review of the literature.

[A case of groove pancreatitis with a characteristic pathologic feature].

Groove pancreatitis is a rare form of chronic pancreatitis in which scarring is found mainly in the groove between the head of the pancreas, duodenum, and common bile duct. The pathogenesis of groove pancreatitis is still unclear but seems to be caused by the disturbance of pancreatic outflow through Santorini duct. It is often difficult to differentiate preoperatively between groove pancreatitis and pancreatic head carcinoma. Whereas conservative management is effective, some patients with duodenal obstruction may undergo Whipple's operation. A few cases of groove pancreatitis have been reported in Korea, and they were diagnosed only by clinical and radiological features. We experienced a case of groove pancreatitis who needed a surgical management because of severe duodenal obstruction. We report the case with a review of its characteristic pathologic findings.

Risk of advanced proximal adenoma and cancer according to rectosigmoid findings in the Korean population.

Colorectal cancer is one of the leading causes of cancer death in the United States and Europe. Recently, the incidence of colorectal cancer has been increasing remarkably in Korea. To reduce the high incidence, screening of colorectal cancer in asymptomatic individuals has been advocated. Sigmoidoscopy is simpler, faster, and better tolerable than total colonoscopy, but the scope cannot reach the proximal colon segment and, therefore, may miss proximal colon cancer. In the present study, we intended to investigate the prevalence of proximal adenoma and cancer according to the findings in rectosigmoid colon and to find their risk factors. Data were collected retrospectively from 1541 consecutive patients who underwent total colonoscopy at the Department of Gastroenterology, Hanyang University, between October 2003 and December 2004. Neoplasms were classified as diminutive adenoma (< or =5 mm), small adenoma (6-9 mm), advanced adenoma (> or =10 mm, with villous component or high-grade dysplasia), and cancer. The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal (from cecum to descending colon) colon. The prevalence of advanced proximal adenoma was associated with severe rectosigmoid findings. On the other hand, the prevalence of proximal colon cancer did not show such a tendency. Among the 131 patients with proximal advanced adenoma, 66% had no neoplasm in the rectosigmoid colon. Moreover, among the 27 patients with proximal cancer, 52% had no neoplasm in the rectosigmoid colon. Multivariate logistic regression analysis revealed that age, gender, and advanced rectosigmoid adenoma were the risk factors of advanced proximal adenoma, but nothing was associated with the risk for proximal colon cancer. Advanced rectosigmoid adenoma may be the predictor of advanced proximal adenoma, especially in old males. However, nothing is related to the risk for proximal colon cancer. Therefore, colonoscopy may be more adequate for colorectal cancer screening than sigmoidoscopy in the Korean population.

High-grade hepatic mucosa-associated lymphoid tissue (MALT) lymphoma probably transformed from the low-grade gastric MALT lymphoma.

The Mucosa-associated lymphoid tissue (MALT) lymphoma, which was first described in 1983, is known to be caused by chronic Helicobacter pylori (HP) infection, which triggers lymphoid infiltration and formation of organized lymphoid tissue. In approximately two thirds of cases of MALT, the lymphoma has been observed to regress after treatment of H. pylori infection; this provides strong evidence of a causative role of HP in the etiology of MALT. We report a case of a 67-year-old female patient with a high-grade MALT lymphoma of the liver; this occurred six years after complete remission of a low-grade gastric MALT lymphoma and after complete eradication of H. pylori. there was no recurrence of the previous low-grade gastric MALT lymphoma. Based on radiological and pathologic findings, the high-grade MALT was considered to result from transformation of the low-grade gastric MALT lymphoma.

Localized esophageal ulcerations after CyberKnife treatment for metastatic hepatic tumor of colon cancer.

CyberKnife is an image-guided robotic system designed for stereotactic radiosurgery. It uses the combination of robotics and image guidance to deliver concentrated and accurate beams of radiation to intracranial and extracranial targets. Although the frameless nature of the CyberKnife allows tumors in the chest and abdomen to be treated as well, complications associated with CyberKnife treatment have not been established yet due to its short clinical experience. We describe a case of localized esophageal ulcerations after CyberKnife treatment for metastatic hepatic tumor of colon cancer.

Attenuation of colonic inflammation by PPARgamma in intestinal epithelial cells: effect on Toll-like receptor pathway.

The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor highly expressed in the colon and playing an anti-inflammatory role through inhibition of the NF-kappaB pathway. Toll-like receptor 4 (TLR4) has been known to mediate LPS-induced cellular signaling through activation of NF-kappaB pathway in intestinal epithelial cells. The aims of this study were to evaluate attenuation of inflammation by PPARgamma in intestinal epithelial cells and to study the possible relation between PPARgamma and TLR4. HT-29 human epithelial cells were stimulated with LPS (20 microg/ml) and PPARgamma ligand, 15d-PGJ2 (10 microM), or with LPS (20 microg/ml) alone for 24 hr. COX-2, IL-8, TLR4, and PPARgamma mRNA expression was assessed by RT-PCR. IL-8 protein levels and TLR4 protein expression were analyzed by ELISA and Western blot, respectively. To evaluate the action mechanisms of PPARgamma ligand, Western blot analysis for IkappaBalpha degradation was performed. Costimulation with LPS and PPARgamma ligand in comparison to LPS stimulation alone (1) decreased COX-2, IL-8 mRNA expression and IL-8 protein secretion, (2) decreased TLR4 mRNA and protein expression, and (3) decreased PPARgamma mRNA expression. PPARgamma ligand delayed LPS-induced IkappaBalpha degradation. These findings suggest that PPAR-gamma ligands suppress inflammation in intestinal epithelial cells. PPARgamma and TLR, these two antagonistic signaling pathways in intestinal epithelial cells may be partially cross-linked.