Toshiki Yamamoto

Intragenic Tsc2 Somatic Mutations as Knudson's Second Hit in Spontaneous and Chemically Induced Renal Carcinomas in the Eker Rat Model

We searched for the rat homologue of the human tuberous sclerosis (TSC2) gene mutations in loss of heterozygosity (LOH)‐negative Eker rat renal carcinomas (RCs) by polymerase chain reactionsingle‐strand conformational polymorphism (PCR‐SSCP) analysis using 45 primer sets covering all 41 coding exons and one leader exon including splicing donor/acceptor sites. We have identified intragenic somatic mutations in 7 of 21 spontaneous RCs, including one cell line (33%), and in 3 of 9 (33%) N‐ethyl‐N‐nitrosourea (ENU)‐induced LOH‐negative RCs. Interestingly, five mutations in the spontaneous RCs were either deletion or duplication (5/7=71%). In contrast, all three in ENU‐induced RCs were base substitutions (3/3 = 100%), as expected. Thus, a qualitative difference in the second hit might exist between spontaneous and ENU‐induced mutations (e.g., deletion or duplication versus point mutation). By a direct cloning approach utilizing the restriction length difference caused by germline insertional mutation or reverse transcriptase‐PCR analysis in two applicable cases, we could clearly show the presence of intragenic somatic mutations in the second copy (wild‐type) of the Tsc2 gene. This is the first demonstration at the DNA sequence level of the validity of Knudsons two‐hits hypothesis in the Tsc2 gene.

Recombination Hot Spot of Hepatitis B Virus Genome Binds to Members of the HMG Domain Protein Family and the Y Box Binding Protein Family; Implication of These Proteins in Genomic Instability

Objective: Previously we hypothesized that the occurrence of hepatocellular carcinoma (HCC) is enhanced by genomic instability induced by the integrated hepatitis B virus (HBV) DNA. Using an in vitro recombination assay, we showed that a subgenomic fragment of HBV DNA designated 15AB (nt1855–1914) is indispensable for in vitro recombination, and also showed the existence of 15AB binding protein. On the assumption that the 15AB binding protein may be a candidate cellular recombinogenic protein which accelerates genomic instability and hepatocarcinogenesis, we tried to isolate it by southwestern screening. Results and Conclusion: We obtained several positive clones including mouse upstream binding factor (UBF) and DNA binding protein A (dbpA). UBF belongs to an HMG domain protein family and dbpA belongs to a Y box binding protein family. 15AB binding seemed to be mediated by the conserved DNA binding domains in these families, because other members in the families such as HMG1 and YB-1 also bound to 15AB. We report them here because several documents have already suggested the possible association of these families and DNA recombination.

Efficacy of a microballoon catheter in transarterial chemoembolization of hepatocellular carcinoma using miriplatin, a lipophilic anticancer drug: Short-term results

The goal of the study was to evaluate the efficacy and safety of balloon‐occluded transarterial chemoembolization (B‐TACE) of hepatocellular carcinoma (HCC) using miriplatin (a lipophilic anticancer drug) and gelatin particles.

Clinical efficacy of contrast-enhanced ultrasonography (CEUS) in the diagnosis of ruptured hepatocellular carcinoma (HCC).

PurposeTo evaluate the role of contrast-enhanced ultrasonography (CEUS) in the diagnosis of ruptured hepatocellular carcinoma (HCC).MethodsCEUS and angiography were performed in ten cases of ruptured HCC. We evaluated whether this technique allowed us to determine the bleeding point by observing an extravasation of contrast media into the ascites.ResultsIn four of the ten cases, CEUS demonstrated an extravasation of Levovist into ascites. Angiography showed an extravasation of contrast medium in three of these four cases. In three of the remaining six cases, in which CEUS did not show the presence of contrast medium in ascites, angiography demonstrated an extravasation. In eight cases, it yielded cessation of bleeding. In two cases, embolization was not successful. The bleeding point was not determined by CEUS or angiography in one case.ConclusionCEUS allows us to differentiate active bleeding (presence of contrast medium in the ascites) from nonactive bleeding.

Evaluation of malignancy of hepatocellular carcinoma using the ultrasonic B-mode method: clinical significance of extracapsular invasion of hepatocellular carcinoma using ultrasonography.

PurposeTo determine the influence of capsule formation or presence of capsular invasion on the prognosis of hepatocellular carcinoma (HCC) patients.MethodsThe patient group consisted of 70 patients with 74 HCC lesions who had been examined by US and undergone surgical tumor resection at our institution. For these patients, we conducted the following comparative studies: (a) comparison between halo findings on US and microscopic capsular results; (b) comparison between halo findings on US and tumor diameter, tumor histological differentiation, and serum value of each tumor marker; and (c) comparison between halo findings on US and tumor recurrence.Results(a) The corresponding value between sonographic halo and histological capsule was 90.1%, and that between presence of extracapsular invasion on US and that seen by histology was 88.0%. (b) There was no relation between US images and histological differentiation of tumors. (c) Presence of extracapsular invasion on US was a predisposing factor for the development of tumor recurrence.Conclusion(1) Globally speaking, sonographic halo corresponded to the histological tumor capsule. (2) In patients with extracapsular invasion, tumor recurrence after treatment increased. Thus, a better understanding of sonographic halo findings helps determine diagnostic and therapeutic strategies in HCC patients.

Molecular Diagnosis of Hepatitis C Viral Infection

With the evolution of confirmatory assays for hepatitis C viral infections, bulk populations of unknown hepatitis were diagnosed as hepatitis C virus (HCV)-mediated chronic liver dysfunction throughout the world. More recently, several systems for molecular diagnosis of hepatitis C viral infections were developed. These are commonly performed for efficient antiviral therapy using interferon. Now we are at the crossroads studying hepatitis virology for the development of sensitive and powerful treatment against HCV-mediated chronic liver dysfunction. Here we introduce the current strategy for the advanced diagnosis of hepatitis C viral infection and discuss the exploration of novel hepatitis viruses.

The thread and streaks sign

A 72-year-old man with hepatitis C virus-related liver cirrhosis was admitted to our hospital for intra-arterial chemotherapy for recurrent hepatocellular carcinoma after undergoing radiofrequency ablation and transarterial embolization. The patient had undergone valve replacement for mitral regurgitation at the age of 66. Physical examination revealed no abnormalities. The patient was classifi ed as Child–Pugh B. Abdominal ultrasonography (US) (LOGIQ 7, GE Healthcare, Milwaukee, WI, USA) showed a 35-mm hypoechoic mass in segment 8 and a 40mm hypoechoic mass in segment 3, with a heterogeneous echo pattern of the liver. An isoechoic solid lesion was seen in the umbilical portion of the left portal vein and left medial portal vein (Fig. 1). Although color Doppler US demonstrated only spotty signals in this lesion, B-fl ow with cine capture showed fi ne parallel vessels (Fig. 2a,b). Abdominal angiography revealed the thread and streaks sign in the left lobe of the liver (Fig. 3).

A Case of Suspected Hepatically Localized Granulomatosis with Polyangiitis

The patient was a 72-year-old woman whose alkaline phosphatase levels had been elevated since she was 56 years old. Liver biopsies obtained when the patient was 64 and 66 years of age led to a suspicion of cholangitis caused by vasculitis. Furthermore, proteinase-3 anti-neutrophil cytoplasmic antibody positivity led to a suspicion of granulomatosis with polyangiitis, but subjective symptoms and disorders in other organs were absent, so this suspicion was not confirmed. Cholangitis caused by vasculitis rarely occurs without vasculitis in other organs. We herein report this case in which we obtained distinctive laparoscopic and imaging findings that raised suspicions of liver circulatory failure.

Involvement of Ornithine Carbamoyltransferase in the Progression of Chronic Hepatitis C and Liver Cirrhosis

Background: The involvement of serum ornithine carbamoyltransferase (OCT) in the progression of chronic hepatitis and liver cirrhosis is unclear. Methods: A total 256 patients with chronic hepatitis C and 5 healthy controls were examined. Serum OCT concentrations were measured by enzyme-linked immunosorbent assay. Serum OCT concentrations were compared with serum cytokine and chemokine levels, and with disease severity and development of hepatocellular carcinoma (HCC). Results: The median OCT concentrations were 21.8 ng/ml for healthy controls, 36.7 ng/ml for F0 stage disease, 48.7 ng/ml for F1 stage, 77.9 ng/ml for F2 stage, 104.8 ng/ml for F3 stage, and 121.4 ng/ml for F4 stage. OCT concentrations were correlated with aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transpeptidase, platelet counts, indocyanine green retention rate at 15 min, prothrombin times, the molar ratio of branched chain amino acids to tyrosine, and tyrosine. Furthermore, there were significant correlations among OCT concentrations and IP10 and IL18 levels. There were weak correlations between serum OCT concentrations and liver histology. The cumulative incidence of HCC in the high-OCT concentration group (≥75.3 ng/ml) was higher than that in the low-OCT concentration group. Conclusion: The measurement of serum OCT concentration may provide a useful marker of disease severity, and thus could be a useful marker for a high risk of HCC occurrence.

Solitary Variceal Rupture in the Small Intestine

A 70-year-old man was referred to our hospital to undergo treatment for hepatocellular carcinoma. In hospital, he complained of hematochezia and a laboratory analysis revealed a decreased level of hemoglobin. Abdominal computed tomography revealed a tumor in the small intestine, with slow enhancement of the dorsal region. Double-balloon enteroscopy revealed a submucosal tumor with a depression in the jejunum. Partial enterectomy was performed and a pathological examination demonstrated the presence of a solitary varix. Solitary varix in the small intestine has not been reported previously. We herein report an extremely rare case of solitary varix in the jejunum.