Ryohei Miyata

Accuracy of preoperative prediction of microinvasion of portal vein in hepatocellular carcinoma using superparamagnetic iron oxide-enhanced magnetic resonance imaging and computed tomography during hepatic angiography

BackgroundOur aim was to diagnose microinvasion of the portal vein in hepatocellular carcinoma from preoperative radiological findings and to construct a scoring system.MethodsForty-seven patients (38 men and 9 women; median age, 66.8 years) who underwent hepatic resections for hepatocellular carcinoma were selected retrospectively. Microscopically, 22 had portal vein invasion (PVI) and 25 had no PVI. All patients were examined preoperatively with superparamagnetic iron oxide-enhanced magnetic resonance imaging and computed tomography during hepatic angiography (CTHA). Perilesional enhancement on T1-weighted imaging, tumorous arterioportal (AP) shunt, and corona enhancement (contrast enhancement of the adjacent liver appearing in the late phase of CTHA) were assessed. Relative risk for PVI in terms of clinical and tumor characteristics was also assessed. The relative contribution to PVI was determined by the coefficient of a stepwise logistic regression. Each variable was given a score relative to the coefficient.ResultsOn univariate analysis, distortion of corona, tumorous AP shunt, and tumor size indicated a higher prevalence of PVI. The PVI predictive score was calculated as: total score = (maximum size in cm) + (T1 ring; + = 1, − = 0) + (tumorous AP shunt; + = 3, − = 0) + (distortion of corona; + = 10, − = 0). The PVI (+) group score was four times that of the PVI (−) group (16 vs 4). At a cutoff score of 10, the sensitivity, specificity, and accuracy were 82%, 84%, and 86%.ConclusionsDistortion of corona, tumorous AP shunt, and tumor size are good predictors of the risk of PVI. This scoring system is simple and worth using clinically.

Clinical characteristics of thrombotic microangiopathy following ABO incompatible living donor liver transplantation

Thrombotic microangiopathy (TMA) may develop after living donor liver transplantation (LDLT), but the mechanism is not fully understood. We retrospectively analyzed all patients undergoing LDLT at our center, including TMA patients, to elucidate the clinical characteristics and presentation and to determine which patients have a higher risk of occurrence of TMA. In all, 57 adult patients were reviewed after LDLT at our institution. TMA was diagnosed by sudden and severe thrombocytopenia, followed by hemolytic anemia with fractionated erythrocytes in the blood smear. Clinical features were compared between the TMA group and the non‐TMA group. Of the 57 patients, 4 were diagnosed with posttransplantation TMA. ABO blood group (ABO)‐incompatibility, cyclophosphamide (CPA), and recipient blood group (type O) were closely correlated with the occurrence of TMA. Thrombocytopenia appeared 1 to 5 days before hemolytic anemia. Coagulative function markers stayed at the same level after TMA, while marked elevation was shown in fibrinolytic function markers such as plasminogen activator inhibitor type 1 (PAI‐1). TMA occurred at a higher prevalence in ABO‐incompatible graft recipients. Additional factors associated with ABO‐incompatible transplantation, such as an overdose of immunosuppressants, may affect the likelihood of TMA. Sudden and severe thrombocytopenia presented before hemolytic anemia and the serum levels of PAI‐1 correlated well with the clinical course of TMA. In conclusion, early recognition of thrombocytopenia and elevation of PAI‐1 is crucial to diagnose TMA especially in ABO‐incompatible LDLT. Liver Transpl 13:1455–1462, 2007.

Selective targeting by preS1 domain of hepatitis B surface antigen conjugated with phosphorylcholine-based amphiphilic block copolymer micelles as a biocompatible, drug delivery carrier for treatment of human hepatocellular carcinoma with paclitaxel

Using dithioester‐capped 2‐methacryloyloxyethyl phosphorylcholine (MPC) as a macro chain transfer agent, a diblock copolymer was synthesized with n‐butyl methacrylate (BMA) as hydrophobic core‐forming blocks. The MPC–BMA unit was copolymerized with an immobilizable unit, p‐nitrophenylcarbonyloxyethyl methacrylate (NPMA). The NPMA moiety then was modified by the addition of preS1 domain of hepatitis B surface antigen (HBsAg). This micelle‐forming nanoparticle, the poly (MPC‐co‐BMA‐co‐NPMA) (PMBN) conjugated with preS1 enables solubilization of paclitaxel (PTX) with increased hepatotropism. The 50% inhibitory concentration (IC50) values of PTX and PTX/PMBN‐preS1 against the human hepatocellular carcinoma cell line, HepG2, were 1,008 and 131 nM, respectively (p < 0.05). Conjugation of preS1 to PMBN enhanced strongly the synergistic inhibitory effect of paclitaxel on HepG2 cells in vitro, whereas such a change in IC50 was not detected against the human squamous cell carcinoma cell line, A431. Tumor growth rates of a HepG2 xenograft in Balb/c nude mice after intraperitoneal injection of PTX, PTX/PMBN and PTX/PMBN‐preS1 were +97.9%, −74.3% and −96.2%*, respectively (*p < 0.05 versus PTX). The local paclitaxel levels after administration of the PMBN‐preS1 conjugate were determined in the xenografts by high‐performance liquid chromatography and were 8 times higher than that after administration of paclitaxel alone. No side effects attributable to PMBN‐preS1 were observed histologically in vital organs, and body weight loss was significantly less in the PTX/PMBN‐preS1 group. These studies demonstrate that PMBN‐preS1 may be used as a human hepatocyte‐specific drug delivery carrier without serious adverse effects.

Vascular pedicled jejunal Roux-en-Y reconstruction with supercharge technique for necrosis of the gastric tube following subtotal esophagectomy

Necrosis of the esophageal conduit is a life-threatening complication in esophageal cancer surgery, and secondary reconstruction options for esophageal discontinuity are quite limited. We present a procedure in which we used a long-segment jejunal flap with a supercharged vascular pedicle to treat gastric tube necrosis following subtotal esophagectomy in a 64-year-old man with esophageal cancer. The proximal jejunal flap was pulled up in Roux-en-Y fashion through the subcutaneous route together with the vascular pedicle of the fourth branch of the jejunal vessels, and the cut edges of the second jejunal vessel were anastomosed microscopically to the internal thoracic vessels for supercharging. No problems occurred with either vessel or digestive tract anastomosis. The patient was able to commence oral intake on postoperative day (POD) 10, was discharged on POD 37, and obtained a good quality of life at home. This result suggests that supercharged vascular pedicled jejunum is a suitable alternative conduit for secondary reconstruction following necrosis of the esophageal conduit in esophageal cancer surgery.

Impact of obesity on surgical outcome after single-incision laparoscopic cholecystectomy

Introduction: Single-incision laparoscopic cholecystectomy (SILC) is widely used as a treatment option for gallbladder disease. However, obesity has been considered a relative contraindication to this approach due to more advanced technical difficulties. The aim of this report was to review our experience with SILC to evaluate the impact of body mass index (BMI) on the surgical outcome. Patients and Methods: Between May 2009 and February 2013, 237 patients underwent SILC at our institute. Pre- and post-operative data of the 17 obese patients (O-group) (BMI ≥30 kg/m2) and 220 non-obese patients (NO-group) (BMI <29.9 kg/m2) were compared retrospectively. SILC was performed under general anaesthesia, using glove technique. Indications for surgery included benign gallbladder disease, except for emergent surgeries. Results: Mean age of patients was significantly higher in the NO-group than O-group (58.9 ± 13.5 years vs. 50.8 ± 14.0 years, P = 0.025). SILC was successfully completed in 233 patients (98.3%). Four patients (1.7%) in the NO-group required an additional port, and one patient was converted to an open procedure. The median operative time was 70 ± 25 min in the NO-group and 75.2 ± 18.3 min in the O-group. All complications were minor, except for one case in the NO-group that suffered with leakage of the cystic duct stump, for which endoscopic nasobiliary drainage was need. Conclusion: Our findings show that obesity, intended as a BMI ≥30 kg/m2, does not have an adverse impact on the technical difficulty and post-operative outcomes of SILC. Obesity-related comorbidities did not increase the risks for SILC.