Effects of the Temporary Placement of a Self-Expandable Metallic Stent in Benign Pyloric Stenosis

BACKGROUND/AIMS: The use of self-expandable metallic stents (SEMS) is an established palliative treatment for malignant stenosis in the gastrointestinal tract; therefore, its application to benign stenosis is expected to be beneficial because of the more gradual and sustained dilatation in the stenotic portion. We aimed in this prospective observational study to evaluate the efficacy and safety of temporary SEMS placement in benign pyloric stenosis. METHODS: Twenty-two patients with benign stenosis of the prepylorus, pylorus, and duodenal bulb were enrolled and underwent SEMS placement. We assessed symptom improvement, defined as an increase of at least 1 degree in the gastric-outlet-obstruction scoring system after stent insertion. RESULTS: No major complications were observed during the procedures. After stent placement, early symptom improvement was achieved in 18 of 22 patients (81.8%). During the follow-up period (mean 10.2 months), the stents remained in place successfully for 6 to 8 weeks in seven patients (31.8%). Among the 15 patients (62.5%) with stent migration, seven (46.6%) showed continued symptomatic improvement without recurrence of obstructive symptoms. CONCLUSIONS: Despite the symptomatic improvement, temporary SEMS placement is premature as an effective therapeutic tool for benign pyloric stenosis unless a novel stent is developed to prevent migration.

Clinicopathologic Feature of Esophageal Submucosal Tumors Treated by Surgical Approach / 대한소화기학회지

BACKGROUND/AIMS: Submucosal tumors of the esophagus are rare lesions among all esophageal neoplasms. The purpose of this study was to evaluate the clinicopathologic features of esophageal submucosal tumors treated by surgical approach. METHODS: We analyzed the clinicopathologic and endoscopic ultrasonographic features of 18 esophageal submucosal tumors which were treated by surgical approach at Boramae Medical Center and Seoul National University Bundang Hospital from January 2005 to June 2012. RESULTS: The mean age was 48.9 years old and male to female ratio was 2.6:1. Asymptomatic patients were most common (77.8%). In endoscopic ultrasonographic finding, the majority tumor arouse in the middle (55.6%) and lower (44.4%) esophagus, and appeared as hypoechoic lesion (72.2%) in the 4th layer (83.3%). The most common indication for surgical approach was unclear biological behavior of the tumor. Minimally-invasive technique using thoracoscopy was applied for the enucleation (83.3%). The mean diameter of the tumor was 5.4 cm, and the final diagnosis was leiomyoma (89.9%) and gastrointestinal stromal tumor (11.1%). CONCLUSIONS: Leiomyoma was the most common submucosal tumor in esophagus. However, endoscopic ultrasonography was not able to differentiate between leiomyoma and gastrointesinal stromal tumor. For more accurate diagnosis and treatment, minimally-invasive approaches may be suitable for the surgical enucleation of indicated esophageal submucosal tumor.

A Case of Giant Inflammatory Ileal Polyp Removed by Double-Balloon Enteroscopy

Inflammatory fibroid polyps are rare benign tumors of the GI tract, that commonly present with intestinal obstruction as a result of intussusceptions in the small bowel. A 39-year old man visited our clinic with an asymptomatic polypoid mass in the distal ileum that was identified on abdominal computed tomography for postoperative surveillance after total gastrectomy due to previously diagnosed early gastric cancer. Retrograde double-balloon enteroscopy was performed to diagnose the ileal mass and a complete resection of the polyp was performed using snare for polypectomy without complications. The final histological finding was an ileal inflammatory polyp. Balloon-assisted enteroscopy is a valuable modality to diagnose and treat small bowel lesions in lieu of surgical procedures in selected cases.

A Case of Hypopharyngeal Cancer Treated by Endoscopic Submucosal Dissection / 대한소화기학회지

Recent advances in endoscopic instruments, including narrow-band imaging (NBI) and magnification endoscopy, allowed dramatic increase in the early diagnosis of hypopharyngeal cancers. In addition, endoscopic mucosal resection or endoscopic submucosal dissection has recently been used for the treatment of hypopharyngeal cancer at an early stage, especially in Japan. However, to date, there is no published report in Korea. A 68-year-old man was admitted for preoperative evaluation and treatment for known esophageal cancer initially diagnosed at a local clinic. During the evaluation, magnifying endoscopy combined with the NBI system revealed a concurrent hypopharyngeal cancer not detected by initial conventional endoscopy. In this case report, we describe for the first time in Korea a case of early stage hypopharyngeal carcinoma that was successfully treated by endoscopic submucosal dissection with a review of literature.

Sciatic nerve regeneration using calcium phosphate coated conduit and brain-derived neurotrophic factor gene-transfected schwann cell in rat

PURPOSE OF STUDY: Peripheral nerve regeneration depends on neurotrophism of distal nerve stump, recovery potential of neuron, supporting cell like Schwann cell and neurotrophic factors such as BDNF. Peripheral nerve regeneration can be enhanced by the conduit which connects the both sides of transected nerve. The conduit maintains the effects of neurotrophism and BDNF produced by Schwann cells which can be made by gene therapy. In this study, we tried to enhance the peripheral nerve regeneration by using calcium phosphate coated porous conduit and BDNF-Adenovirus infected Schwann cells in sciatic nerve of rats. MATERIALS AND METHODS: Microporous filter which permits the tissue fluid essential for nerve regeneration and does not permit infiltration of fibroblasts, was made into 2mm diameter and 17mm length conduit. Then it was coated with calcium phosphate to improve the Schwann cell adhesion and survival. The coated filter was evaluated by SEM examination and MTT assay. For effective allogenic Schwann cell culture, dorsal root ganglia of 1-day old rat were extracted and treated with enzyme and antimitotic Ara-C. Human BDNF cDNA was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into adenovirus shuttle vector pAACCMVpARS in which E1 was deleted. We infected the BDNF-Ad into 293 human mammary kidney cell-line and obtained the virus plaque 2 days later. RT-PCR was performed to evaluate the secretion of BDNF in infected Schwann cells. To determine the most optimal m.o.i of BDNF-Ad, we infected the Schwann cells with LacZ adenovirus in 1, 20, 50, 75, 100, 250 m.o.i for 2 hours and stained with beta-galactosidase. Rats(n=24) weighing around 300g were used. Total 14mm sciatic nerve defect was made and connected with calcium phosphate coated conduits. Schwann cells(1x10(6)) or BDNF-Ad infected Schwann cells(1x10(6)) were injected in conduit and only media(MEM) was injected in control group. Twelve weeks after surgery, degree of nerve regeneration was evaluated with gait analysis, electrophysiologic measurements and histomorphometric analysis. RESULTS: 1. Microporous Millipore filter was effective conduit which permitted the adhesion of Schwann cells and inhibited the adhesion of fibroblast. We could enhance the Schwann cell adhesion and survival by coating Millipore filter with calcium phosphate. 2. Schwann cell culture technique using repeated treatment of Ara-C and GDNF was established. The mean number of Schwann cells obtained 1 and 2 weeks after the culture were 1.54+/-4.0*10(6) and 9.66+/-9.6*10(6). 3. The mRNA of BDNF in BDNF-Ad infected Schwann cells was detected using RT-PCR. In Schwann cell 0.69 microgram/microliter of DNA was detected and in BDNF-Adenovirus transfected Schwann cell 0.795 microgram/microliter of DNA was detected. The most effective infection concentration was determined by LacZ Adenovirus and 75 m.o.i was found the most optimal. CONCLUSION: BDNF-Ad transfected Schwann cells successfully regenerated the 14mm nerve gap which was connected with calcium phosphate coated Millipore filter. The BDNF-Ad group showed better results compared with Schwann cells only group and control group in aspect to sciatic function index, electrophysiologic measurements and histomorphometric analysis.

Peripheral nerve regeneration using polyglycolic acid conduit and brain-derived neurotrophic factor gene transfected Schwann cells in rat sciatic nerve

PURPOSE: The essential triad for nerve regeneration is nerve conduit, supporting cell and neurotrophic factor. In order to improve the peripheral nerve regeneration, we used polyglycolic acid(PGA) tube and brain-derived neurotrophic factor(BDNF) gene transfected Schwann cells in sciatic nerve defects of SD rat. MATERIALS AND METHODS: Nerve conduits were made with PGA sheet and outer surface was coated with poly(lactic-co-glycolic acid) for mechanical strength and control the resorption rate. The diameter of conduit was 1.8mm and the length was 17mm. Schwann cells were harvested from dorsal root ganglion(DRG) of SD rat aged 1 day. Schwann cells were cultured on the PGA sheet to test the biocompatibility adhesion of Schwann cell. Human BDNF gene was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into E1 deleted region of adenovirus shuttle vector, pAACCMVpARS. BDNF-adenovirus was multiplied in 293 cells and purified. The BDNF-Adenovirus was then infected to the cultured Schwann cells. Left sciatic nerve of SD rat (250g weighing) was exposed and 14mm defects were made. After bridging the defect with PGA conduit, culture medium(MEM), Schwann cells or BDNFAdenovirus infected Schwann cells were injected into the lumen of conduit, respectively. 12 weeks after operation, gait analysis for sciatic function index, electrophysiology and histomorphometry was performed. RESULTS: Cultured Schwann cells were well adhered to PGA sheet. Sciatic index of BDNF transfected group was -53.66+/-13.43 which was the best among three groups. The threshold of compound action potential was between 800 to 1000microA in experimental groups which is about 10 times higher than normal sciatic nerve. Conduction velocity and peak voltage of action potential of BDNF group was the highest among experimental groups. The myelin thickness and axonal density of BDNF group was significantly greater than the other groups. CONCLUSION: BDNF gene transfected Schwann cells could regenerate the sciatic nerve gap(14mm) of rat successfully.

Development of microporous calcium phosphate coated nerve conduit for peripheral nerve repair

This study was performed to develop a useful nerve conduit which provides favorable environment for Schwann cell viability and proliferation. Milipore membrane of 0.45um pore size was selected because it permits nutritional inflow from the outside of the conduit and prevents from invading the fibrotic tissue into the conduit. The membrane was rolled and sealed to form a conduit of 2mm diameter and 20mm length. To improve the axonal regeneration and to render better environment for endogenous and exogenous Schwann cell behaviour, the microgeometry and surface of conduit was modified by coating with thin film of calcium phosphate. Cellular viability within the conduit and attachment to its wall were assessed with MTT assay and SEM study. Milipore filter conduit showed significantly higher rate of Schwann cell attachment and viability than the culture dish. However, the reverse was true in case of fibroblast. Coating with thin film of low crystalline calcium phosphate made more favorable environment for both cells with minimal change of pore size. These findings means the porous calcium phosphate coated milipore nerve conduit can provide much favorable environment for endogenous Schwann cell proliferation and exogenous ones, which are filled within the conduit for the more advanced strategy of peripheral nerve regeneration, with potential of reducing fibrotic tissue production.

Peripheral nerve repair using sural nerve graft

Improved protocol for schwann cell isolation and proliferation from rat dorsal root ganglia in vitro