Ryo Shimada

A study of factors influencing prognosis after resection of hepatic metastases from colorectal and gastric carcinoma.

OBJECTIVE:The aim of this study is to determine the absolute contraindication for hepatic resection for colorectal metastases and investigate the value of hepatectomy for gastric metastases by comparing it with the results of colorectal metastases performed with the same criteria.METHODS:A retrospective cohort study was conducted in patients undergoing hepatic resection for metastatic colorectal (n = 64) and gastric (n = 17) carcinomas. Common predictive factors for both metastases were analyzed by the stratified Cox proportional hazard model. In this model, the different baseline hazard was set for each disease, whereas the risk of each covariate was assumed to be equal in both gastric and colorectal metastases.RESULTS:Overall 1-, 2-, and 5-yr survival rates after hepatectomy for colorectal and gastric metastases were 90%, 73%, 42%, and 47%, 22%, 0%, respectively. Factors controlling prognosis were as follows: age ≥ 60, extrahepatic metastases, serosal invasion, grade of lymph node metastases, tumor cell differentiation of the primary lesion(s), carcinoembryonic antigen level, tumor-exposed surgical margin, and blood transfusion. In particular, presence of extrahepatic metastases showed the markedly high-risk ratio among these eight variables.CONCLUSIONS:Hepatectomy, if possible, is indicated in patients with hepatic metastases from colorectal carcinoma if there are no extrahepatic metastases and if the primary disease is controlled. It is indicated only in carefully selected patients with metastases from gastric carcinoma.

Proximal bile duct stricture disguised as malignant neoplasm

BACKGROUND Discrimination of malignant proximal bile duct (PBD) stricture from a benign lesion is difficult with nonsurgical methods; indeed, 8% to 13% of PBD strictures prove to be benign after histologic examination of the surgically resected specimen. METHODS In a 7-year period 178 patients with PBD stricture were admitted, and 99 of them underwent radical resection for presumably malignant lesions. In 14 of these patients the stenotic lesions were proved to be benign by postoperative histologic assessment. We reviewed these patients retrospectively by collecting data from their charts. RESULTS Preoperative radiologic findings including cholangiography and angiography were compatible with malignancy in all 14 patients. Preoperative histologic studies suggested malignancy in 2 of 8 examined. Findings at laparotomy could not allow differentiation between malignant and benign lesions in any of the patients and strongly suggested malignancy in 3. Histologic examination of the resected specimens revealed extensive fibrosis with inflammatory cellular infiltration in all patients. There was 1 episode of significant morbidity postoperatively (transient cholangitis) but no mortality. CONCLUSION Benign PBD strictures, although rare, are usually indistinguishable from malignant PBD strictures by preoperative or perioperative investigation. Given the minimal morbidity, all PBD strictures should be presumed malignant and managed accordingly, even at the risk of overtreating some benign cases.

Staged hepatectomy after emergency transcatheter arterial embolization for ruptured hepatocellular carcinoma.

BACKGROUND Staged hepatectomy after emergency transcatheter arterial embolization (TAE) has been advocated in ruptured hepatocellular carcinoma (HCC). However, there have been no reports of clinical series of this strategy. The purpose of this study was to evaluate the protocol of this therapeutic strategy. METHODS Sixteen patients with suspected rupture of HCC were included in the study. After emergency TAE, tumor resectability was assessed, followed by staged hepatectomy or repeated TAE. The patients were reevaluated with regard to rupture of HCCs. RESULTS Primary hemostasis was achieved successfully in all patients. Eleven patients were finally judged to have experienced HCC rupture. Seven of them underwent staged hepatectomy; the other four underwent repeated TAE because their tumors were considered unresectable. Survival time tended to be longer, but not to a significant extent, in patients who underwent hepatectomy (range, 139 to 1527 days; median, 375 days) than in those treated by TAE alone (range, 43 to 1317 days; median, 158 days). CONCLUSIONS Staged hepatectomy after TAE is a rational treatment for patients with ruptured HCC. Although TAE is highly effective for initial hemostasis, hepatectomy appears to provide better long-term survival.

BRDF estimation system for structural colors

In this paper, we provide a shading algorithm for Structural Colors which can appear on micro surfaces. To approach a common algorithm for as many micro surfaces as possible, we modeled them out of polygons which have relative index of refraction. The algorithm calculates a surfaces BRDF for each wevelength by ray tracing considering interference. Interference yield different BRDF between each wavelength, and we perceive it as structural colors. We simulated not only single thin film but also multilayered thin films as typical micro surfaces causing structural colors. We illustrated calculated BRDF in 3D computer graphics using environment mapping. Rendering results in our method indicate that it represent structural colors qualitatively.

Plasma Concentration of Endothelin-1 Does Not Reflect Renal Vasoconstriction as Estimated by Duplex Ultrasonography in Cirrhosis

Endothelin, a potent vasoconstrictor, is thoughtto play a role in liver cirrhosis-related functionalkidney failure. Our aim was to investigate thecorrelation between renal vasoconstriction, as detected by a Doppler ultrasound technique, and plasmaconcentrations of endothelin in cirrhotic patients.Fifty cirrhotic patients underwent Doppler examinationsto detect renal vasoconstriction. The plasmaconcentration of endothelin was measured in 10 patients whoexhibited vasoconstriction of the renal microvesselsdiagnosed by Doppler waveform analysis and was comparedto that of patients in whom there was no sign of such vasoconstriction. No difference wasobserved in the plasma concentration of endothelinbetween patients in whom renal vasoconstriction wasdiagnosed and those in whom it was not. Our resultssuggested that the circulating endothelin does notreflect renal vasoconstriction, at least in the earlyphase of the functional renal failure associated withcirrhosis of the liver.

Simulating the Coalescence and Separation of Bubble and Foam by Particle Level Set Method

In this paper, we present a physics-based computer graphics technique for simulating and rendering foams and bubbles floating on the calm surface of fluid. We integrate rendering of bubble and foam, fluid simulation and the interactions between them to create the appearance of realistic liquids. As a whole, the animation of bubble that floats on the surface of fluid becomes possible by the technique of this research.