Jong Hoon Lee

Colonic Stent-Related Complications and Their Management

Since its introduction in the early 1990s, the self-expandable metal stent (SEMS) has been increasingly used for the management of malignant colorectal obstruction, not only as a palliative method but also as a preoperative treatment in surgical candidates. However, more recently, concerns have been raised over stent complication rates. Early complications include pain, perforation, and rectal bleeding, and late complications include stent migration and stent obstruction. With the increasing use of SEMS for treatment, physicians need to be more aware of complications occurring after the placement of these stents. This review covers the technical considerations and management of complications after colonic stenting.

Lessons learned from 100 initial cases of laparoscopic liver surgery

Purpose Laparoscopic liver resection (LLR) is now widely accepted and is being increasingly performed. The present study describes our experience with LLR at a single center over an eight-year period. Methods This retrospective study enrolled 100 patients between October 2002 and February 2010. Forty-six benign lesions and 54 malignant lesions were included. The LLR performed included 58 pure laparoscopy procedures, 18 hand-assisted laparoscopy procedures and 24 hybrid technique procedures. Results The mean age of the patients was 57 years; among these patients, 31 were over 65 years of age. The mean operation time was 220 minutes. The overall morbidity was 11% and the mortality was zero. Among the 20 patients with simple hepatic cysts, 50% unexpectedly recurred. Among the 41 patients with hepatocellular carcinoma, 21 patients (51%) underwent preoperative radiofrequency ablation therapy or transarterial chemoembolization. During parenchymal-transection, 11 received blood transfusion. The width of the resection margins was under 0.5 cm in 11 cases (27%); 0.5 to 1 cm in 22 cases (54%) and over 1 cm in eight cases (12%). There was no port site seeding, but argon beam coagulation-induced tumor dissemination was observed in two cases. The overall two-year survival rate was 75%. Conclusion This study suggests that the applications for LLR can be gradually expanded when assuring that the safety and curability of LLR are equivalent to that of open liver resection.

Gene expression in human gastric adenocarcinoma using cDNA array

Background: cDNA microarray provided a powerful alternative with an unprecedented view scope in monitoring gene expression levels and led to discoveries of regulatory pathways involved in complicated biological processes. Objective: To explore the different gene expression pattern in early and advanced gastric cancer (EGC and AGC) in this study, we have applied eDNA microarray slides containing 4608 human eDNA fragments. Materials and Methods: By using a eDNA microarray, we studied the expression profiling in 10 paired gastric adenocarcinoma samples (2 EGCs, 8 AGCs) and the adjacent noncancerous gastric tissues form the same patients. The alterations in gene expression levels were confirmed by Northern blot and reverse-transcription PCR in all of 4 randomly selected genes. Then, a weighted-voting classification algorithm was applied, and was tested by leave-one-out crossvalidation. The final model which minimized cross-validation errors was chosen. Results: Genes that were differently expressed in cancer and noncancerous tissues were identified. 44 (of which 25 were known) and 92 (of which 50 were known) genes or eDNA were upand down-regulated, respectively, in >80% of the gastric adenocarcinoma samples. In cancer tissues, genes related to signal transduction, metabolism and gene/protein expression were mostly up-regulated, whereas genes related to immunology, cell structure/motility and transcription were mostly down-regulated The semi-quantitative RT-PCR results, for the four genes we tested, were consistent with the array findings. A supervised learning classification process is repeated until all 10 samples are predicted in turn Predictors containing between 16 and 20 genes all yielded statistically significant predictions, with the highest accuracy obtained using 9 genes.(BE880748, NM 015379, AF011374, NM 017458, AL078581, A1524095, NM 018479, U00672, NM 004705) The accuracy of prediction using these 9 genes was 100 % suggesting strong correlation of gene expression pattern in distinction of AGC and EGC. However, there is no correlation between two groups when EGC was randomly selected in AGC. Moreover, the expression pattern strongly indicates that homogeneous gene expression pattern in EGC but not in AGC. Conclusion: Although the sample size is small, these results provide not only a new molecular basis for understanding biological properties of gastric adenocarcinoma, but also useful resources for future development of therapeutic targets and diagnostic markers for gastric adenocarcinoma.