There are many limitations for conducting liver disease research in human beings due to the high cost and potential ethical issues. For this reason, conducting a study that is difficult to perform in humans using appropriate animal models, can be beneficial in ascertaining the pathological physiology, and in developing new treatment modalities. However, it is difficult to determine the appropriate animal model which is suitable for research purposes, since every patient has different and diverse clinical symptoms, adverse reactions, and complications due to the pathological physiology. Also, it is not easy to reproduce identically various clinical situations in animal models. Recently, the Guide for the Care and Use of Laboratory Animals has tightened up the regulations, and therefore it is advisable to select the appropriate animals and decide upon the appropriate quantities through scientific and systemic considerations before conducting animal testing. Therefore, in this review article the authors examined various white rat animal testing models and determined the appropriate usable rat model, and the pros and cons of its application in liver disease research. The authors believe that this review will be beneficial in selecting proper laboratory animals for research purposes.

Benign portal vein thrombosis (PVT) is a challenging complication of an otherwise successful liver transplantation. PVT is caused by various conditions and results in pathologic hemodynamics of hepatofugal diversion of porto-mesenteric blood flow. Thus, adequate restoration of portal blood flow to the liver graft is a major concern when trying to achieve successful liver transplantation in patients with PVT. This letter describes the surgical view point of PVT in liver transplantation.

Purpose: Although surgical resection offers patients with HCC the chance of a cure, the post-resection tumor recurrence rate is high, with reported cumulative 5-year tumor recurrence rates ranging from 40 to 70%. The objective of this study was to investigate risk factors for intrahepatic recurrence after resection of hepatocellular carcinoma, especially in patients with hepatitis B virus infection. Methods: Between January 1999 and December 2003, 59 patients in our Hospital with hepatitis B virus infection underwent liver resection for hepatocellular carcinoma. Clinical, biological, and histopathological characteristics of these patients were collected and tested for their prognostic significance using a Chi-square test and a Student's t-test. Time to recurrence and survival rate were analyzed by the Kaplan-Meier method. Results: Of the 59 patients who underwent liver resection, 24 (41%) experienced intrahepatic recurrence. The 1-, 3-, and 5-year overall survival rates of total enrolled patients were 83%, 63%, and 42%, respectively. The 1-, 3-, and 5-year overall survival rates after recurrence were 87%, 52%, and 20%, respectively. The risk factors for early recurrence were elevated serum aspartate aminotransferase (AST) level (p=0.044) and larger tumor size (p=0.049). For late recurrence, greater tumor size (p=0.039) was the only risk factor. Conclusion: Tumor size and serum aspartate aminotransferase are risk factors of intrahepatic recurrence after resection of HCC in patients with chronic hepatitis B virus infection. This finding indicates that patients who have these risk factors should be under more careful supervision and have more aggressive follow-up.

Purpose: In spite of the recent improved results of hepatectomy for huge hepatocellular carcinomas (HCC), the prognosis of patients with huge HCCs is still poor compared to that of patients with small HCCs. This study was performed to compare the results of hepatectomy between patients with huge HCCs and those with small HCCs, to identify the prognostic factors in patients with huge HCCs, and to determine the preoperative selection criteria. Methods: We retrospectively analyzed 51 patients who underwent hepatectomy, between July 1994 and February 2009 at Dankook University Hospital. Patients with HCC${\geq}$10 cm were classified in large (L) group and others were classified in small (S) group. The clinicopathological features, operative procedures, and postoperative outcome were compared between both groups and various prognostic factors were investigated in group L. Results: Eleven patients were classified in group L. Tumor size, vascular invasion, and tumor stage were higher in group L. Postoperative morbidity was higher in group L, but mortality was not different between the groups. Disease-free survivals were significantly lower in group L than in group S (36.4%, and 24.2% vs. 72.0%, and 44.0% for 1- and 3-year), but overall survival rates were similar in both groups (45.5%, and 15.2% in group L vs. 60.3%, and 41.3% in group S for 3- and 5-year). Presence of satellite nodules was the only prognostic factor in multivariate analysis after surgery for huge HCC. Conclusion: Regardless of tumor size, huge HCCs deserve consideration for surgery in patients with preserved liver function. Furthermore, the effect of surgery could be maximized with appropriate selection criteria, such as huge HCC without satellite nodules.

Purpose: Many studies have been conducted to date regarding whether the right hepatic vein is the accurate border that divides the anterior and posterior section of the right liver. It has been reported that the Glisson pedicle of the right liver may be an anatomical variation that does not have a consistent morphology. We analyzed the relationship between the true borders of the anterior and posterior sections, and the right hepatic vein, based on cadaver dissection and MD-CT image analysis of the anatomical variation of the Glisson pedicle of the right liver. Methods: Sixteen cadaver livers were available for dissection from the Department of Anatomy, and pre-operative MD-CTs of 20 donor livers who underwent living donor liver transplantation prior to December 2009, were obtained. We analyzed the 3D-relationship between the branches of the Glisson pedicles and the right hepatic vein of the right liver. They were divided into 3 groups according to the sliding pattern of the branches of the Glisson pedicle origin. When all segmental branches of the anterior pedicle arise from the main trunk of the anterior pedicle and all branches of posterior pedicle arise from the main trunk of posterior pedicle, it was designated as Group A (Normal Group). When a portion of the segmental branches of the anterior pedicle arises from the main trunk of the posterior pedicle, it was designated as Group B (Posterior dominant group). When a portion of the branches of the posterior pedicle arises from the main trunk of the anterior pedicle, it was designated as Group C (Anterior dominant group). Results: Among the 16 cadaver liver dissections, 6 cases were in Group A, 5 in Group B, and 3 in Group C. Two cases were excluded from the study because the inferior right hepatic vein was the main draining vein of the right liver. The analysis of preoperative MD-CT of the 20 donor livers showed that there were 13, 4, and 3 patients in Groups A, B, and C, respectively. Conclusion: According to Couinaud's theory of anatomy, the right hepatic vein serves as the border between the anterior and posterior sections of the right liver. But, due to the frequent anatomical variations, an adequate understanding of the anatomical variations of the right Glisson pedicle should be necessary for liver surgery.

Purpose: This study is designed to ascertain the most effective quantity and injection route of hepatocytes in an acute liver failure model induced by massive liver resection in rats. Methods: Rats weighing 450 to 650 gm underwent partial hepatectomy that was 80% of their liver weight, resulting in acute liver failure. Hepatocytes were obtained by perfusing collagenase (Wako, Japan) solution through portal vein into liver of the allogenic rat. These hepatocytes were injected into different places with different dosage. The experimental groups were divided into the Control group, Splenic group I($2{\times}10^{6}$ cells into splenic capsule), Splenic group II($2{\times}10^{7}$ cells into splenic capsule), Portal vein group ($2{\times}10^{7}$ cells into portal vein), Subperitoneal group ($2{\times}10^{7}$ cells into subperitoneum). The experimental animals were observed carefully for 5 days for assessment of survival and regeneration of liver. Liver function tests including serum alanine aminotransferase (ALT), total bilirubin, gamma-glutamyl transferase (${\gamma}$-GTP) on postoperative 1, 2, 3, 5th days and histologic examinations of specimens obtained from each respective groups on postoperative 5th day were performed. Results: Serum ALT level on postoperative day 1 peaked and then gradually normalized showing statistical significance (p=0.035). Study groups showing statistically significant difference under repeated anova analysis were between the Splenic group II and Control (p=0.035), and between the Splenic group II and Portal vein group (p=0.001) with respect to serum ALT levels. Also, progression of each study group showed statistical significance. (p=0.02). Serum total bilirubin and r-GTP did not show any significant difference. Conclusion: Hepatocyte transplantation of $2{\times}10^{7}$ cells into spleen showed the best results in the acute hepatic failure rat.

Purpose: T-tube is a major procedure that prevents complication by biliary decompression, but which is accompanied by complications. Therefore, several procedures such as ENBD, PTBD, and antegrade biliary stent have been attempted, but with controversies as to which procedure is superior. Also, there are no standard procedures after laparoscopic CBD exploration. We performed this study to ascertain the most appropriate biliary drainage procedure after laparoscopic CBD exploration. Methods: From March 2001 to December 2009, 121 patients who underwent Laparoscopic CBD exploration in Gunyang University were included for retrospective analysis. The patients were divided to 4 groups according to type of procedure, and we compared clinical parameters including age and gender, operation time, hospital stay, start of post-operative diet, and complications. Results: There was no difference in age, gender, mean operation time, postoperative diet between the 4 groups. Hospital stay in the Stent group was shorter than T-tube group. There were 10 (7%) complications that occurred. Two 2 occurred in the T-tube, 3 in PTBD, and 5 in the Antegrade stent group. There were more complications in Stent group but no significant statistical difference. In 5 cases with remnant CBD stone, a total of 4 (3 PTBD, 1 Stent) was performed by endoscopic CBD stone removal. One T-tube case was removed easily by choledochoscopy through the T-tube. Three migrated and the impacted stents were removed by additional endoscopy. Perioperative biliary leakage (1) and peritonitis (1) post t-tube removal were resolved by conservative treatment Conclusion: T-tube appears to be an appropriate method to patients who are suspected to have remnant CBD stones. Multiple procedures may be performed on a case by case basis such as performing PTBD first in a suspected cholangitis patient.

Purpose: Pancreatectomy can impair production of endocrine and exocrine hormones. In this study, we evaluated: 1) the incidence rate of diabetes in patients undergoing distal pancreatectomy; 2) the correlation between the occurrence of pancreatic diabetes and the extent of the resected pancreas; and 3) factors associated with the development of pancreatic diabetes. Methods: We retrospectively reviewed the cases of 26 patients who could be compared in abdominal computed tomography before and after distal pancreatectomy for benign or malignant lesions between January, 1999 to June, 2010. Results: The incidence of pancreatic diabetes was 19.2%. Obese patients (BMI>25.0 kg/$m^{2}$) had a higher incidence (p=0.029) of pancreatic diabetes after distal pancreatectomy than non-obese patients. The diabetes group had larger volumes of resected pancreas, but the difference was not statistically significant (p=0.105). Conclusion: Several factors may be associated with the development of pancreatic diabetes after distal pancreatectomy. It is necessary to closely follow-up development of pancreatic diabetes regardless of the extent of resection.

Purpose: In Korea, there are few reports regarding the infiltration of fat tissue in pancreatic parenchyma in surgically resected organs. It is necessary to ascertain the correlation between the presence of fat tissue in the resection margin of the pancreas and the surgery outcome. Methods: Fifty four patients who underwent pancreatic resection from Jan. 2007 to Nov. 2008 were enrolled in this study. Pathologic examination was performed to determine the presence of fat tissue in resected pancreatic parenchyma. Statistical correlation between the presence of fat tissue with clinical parameters and postoperative complication rates was analyzed. Results: Among the specimens of all fifty four patients, fat tissue was found in 32 specimens of patients (59.3%). Female gender and patients whose body mass index exceeded 24 kg/$m^{2}$ were statistically correlated with the presence of the fat tissue in pancreatic parenchyma. There was no statistical relationship between infiltration of fat tissue with postoperative complications. Conclusion: This study may serve as the base data for study in radiological imaging in detecting pancreatic tissue. A further larger scaled study is needed to validate the result of this study.

Serous cystic neoplasm (SCN) of the pancreas is considered a benign tumor with almost no malignant potential. Most surgeons agree that asymptomatic SCN requires only regular observation. However, several complexities and interference with organ preservation during the operation, may develop when a huge symptomatic tumor is treated with surgery. So, the purpose of this study is to develop a potential management plan based on a literature review and by describing three recent cases of SCN of the pancreas. We suggest that SCNs be responded to with a timely and appropriate surgical intervention - before they require clinical attention.