Soo Won Suh

Effect of different particles on cell proliferation in polymer scaffolds using a solvent-casting and particulate leaching technique.

Solvent-casting and particulate leaching are widely used in the manufacturing of porous polymer scaffolds. Salt is the most commonly used particulate because it is easily available and very easy to handle. Gelatin particles are another candidate for this method because they are known as a material that enhances cell attachment and proliferation. In this study, we compared the biocompatibility of the two scaffolds made from either salt (salt scaffold) or gelatin particles (gelatin scaffold). Sieved particles of salt and gelatin (particle size ranging 100–180 um) were dispersed in a poly-lactic-co-glycolic acid (PLGA)/chloroform solution and cast in a Teflon container. The solvent was allowed to evaporate and residual amounts were removed by vacuum drying. The particles were allowed to leach out by immersion in warm water (40°C). Cultured chondrocytes (from knee cartilage) and smooth muscle cells (from bladder) were seeded on each scaffolds (5 × 106/cm2) and cultured for 3 weeks, and their proliferation was compared using hematoxylin and eosin staining. These results demonstrated that the gelatin scaffold showed better attachment of cells at the initial stage, and both cell types showed much better proliferation of cells during 3 months. The better performance of a gelatin scaffold also contributed to the better connection of pores at the same porosity.

Lacrimal Canalicular Obstructions: Safety and Effectiveness of Balloon Dilation☆

PURPOSE 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. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSIONS 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.

Replacement of a tracheal defect with autogenous mucosa lined tracheal prosthesis made from polypropylene mesh.

Reliable prosthetic or tissue grafts for the trachea have not, as yet, been developed for reconstruction of large, circumferential tracheal defects. Major limitations are anastomotic dehiscence and stenosis, attributed to the poor epithelialization and vascularization of the prosthetic graft. We have developed a new tracheal prosthesis that has a well vascularized and viable mucosa. The prosthesis consists of a Prolene mesh reinforced with polypropylene rings, and coated with gelatin. We lined the luminal surface of the prosthesis with transplanted autogenous oral mucosa, wrapped the prosthesis with greater omentum, and placed it in the peritoneal cavity for 2 weeks. Complete surgical resection and replacement of a segment (5 cm in length, 8 to 10 tracheal rings) of the thoracic trachea was then performed in nine adult mongrel dogs. The transplanted mucosa was well vascularized and maintained its normal histology in prereplacement analysis. Dogs with tracheal replacement regained their full activity and did not show any respiratory problems until sacrifice at 1, 2, and 6 months. After 6 months, the prostheses were completely incorporated by the host trachea in all dogs and confluent epithelialization was confirmed histologically from the upper to the lower anastomotic site of the prosthesis; furthermore, the transplanted mucosal cells had changed to ciliated columnar epithelium.

Malignant Esophagogastric Junction Obstruction: Palliative Treatment with an Antireflux Valve Stent

The authors assessed the efficacy of an antireflux valve stent in the palliation of malignant esophagogastric junction (EGJ) obstruction after in vitro testing of the stent. Seventeen patients with inoperable malignant EGJ obstruction were treated. Antireflux valves, made of three polyurethane leaflets, were attached to the distal part of the stent to prevent reflux. When the flow rate of normal saline was 100 mL/sec in the forward direction, the valve fully opened at a pressure of 10 mm Hg. When the flow rate of normal saline was 0.35 mL/sec in the backward direction, the valve nearly completely closed at a pressure of 10 mm Hg. Stent placement was successful in all patients without complications. The median dysphagia score decreased significantly, from 3.0 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food) (P < .0005). No patients experienced reflux symptoms. There was one case of stent migration. A valve stent that can prevent major reflux is an effective device for the palliation of malignant EGJ obstruction.

Comparison of natural and Dumon airway stents for the management of benign tracheobronchial stenoses.

Objective and background:  To investigate the utility and safety of the ‘Natural stent’, a newly designed silicone airway stent, the authors compared clinical outcomes and complications in patients who underwent silicone airway stenting for the management of benign airway stenosis.

Mouse orthotopic lung cancer model induced by PC14PE6.

PURPOSE This study was undertaken to investigate in detail the xenograft mouse orthotopic lung cancer model induced by PC14PE6 adenocarcinoma cells. MATERIALS AND METHODS Three cell doses (0.5x10(6); 1x10(6); 2x10(6)) of PC14PE6 cells were injected into the lungs of male BALB/c nude mice by the intrathoracic injection method. The lung and other organs, including brain, liver, spleen, kidney, muscle, adrenal gland, and lymph node on knee, were removed and stained with H/E to detect the presence of tumor cells. RESULTS The reliable tumorigenicity time in the PC14PE6 adenocarcinoma cell-inoculated BALB/c nude mouse was 10 days after intrathoracic injection. The average life span of the three groups after inoculation was 14 days in the 2x10(6) cells inoculum group; 25 days in the 1x10(6) cells inoculum group; and 32 days in the 0.5x10(6) cells inoculum group. The PC14PE6 adenocarcinoma cells induced orthotopic lung cancer limited within the thorax. CONCLUSIONS This orthotopic lung cancer model is an efficient cancer model with easy inoculation methods, rapid and high tumorigenicity, and simple monitoring methods for metastasis.