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1.
Transplant Proc ; 50(9): 2882-2884, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30401416

ABSTRACT

The effective treatment for hepatocellular carcinoma (HCC) with American Joint Committee on Cancer stage IIIB remains controversial and challenging because of the high recurrence rate after resection and low survival rate. The median survival of those with macroscopic portal vein tumor thrombus (PVTT) is short. We reported such a case which received liver transplantation (LT) after successful consecutive downstaging therapies. A 40-year-old man with alcohol related liver cirrhosis and repeated esophageal varices bleeding had HCC with tumor thrombi in right main portal vein and the second portal branch of segment VI (stage IIIB). The received percutaneous alcohol injection, radiofrequency ablation, 8 sessions of transcatheter hepatic arterial chemoembolization, radiotherapy, and target therapy with sorafenib. Computed tomography (CT) scan and magnetic resonance imaging after treatments showed no viable fragments in the tumor and revealed both the right main portal vein and V1 branch were patent. One month later, the patient received a deceased LT. The perioperative course was rather smooth. After discharge, the interval follow-up CT studies of the chest and liver and whole body bone scan showed no tumor recurrence or metastasis up to 20 months postoperation.


Subject(s)
Carcinoma, Hepatocellular/therapy , Combined Modality Therapy/methods , Liver Neoplasms/therapy , Liver Transplantation/methods , Adult , Carcinoma, Hepatocellular/pathology , Humans , Liver Neoplasms/pathology , Male , Middle Aged , Portal Vein/pathology , Thrombosis/pathology , Treatment Outcome , United States
2.
Transplant Proc ; 48(4): 1149-55, 2016 May.
Article in English | MEDLINE | ID: mdl-27320576

ABSTRACT

BACKGROUND: Hepatic artery pseudoaneurysm (PA) after liver transplantation (LT) is a rare but potentially fatal complication. Among a series of 50 patients of LT, we experienced 3 such cases. Some authors also have reported cases of PA, either intrahepatic or extrahepatic. The aim of this study was to investigate the important factors that affect the treatment outcome. METHODS: Three patients were presented. To analyze the factors, not only our patients but also the patients with PA reported in the literature (including 10 case series and 23 case reports) were enrolled for analysis. The possible factors probably affecting the survival were compared statistically, including age, sex, clinical manifestation as bleeding (including gastrointestinal bleeding, hemobilia, or intra-abdominal bleeding), treatment (with embolization or surgical exploration or stent), diagnosis establishment before or after bleeding, and so forth. RESULTS: From univariate analysis, the significant factors that affect survival are sex (female) (P = .036), stent treatment (P = .006), and early detection (P = .036), whereas age (P = .493) and presentation with hemorrhage (P = .877) are not significant factors. However, according to multivariate analysis, stent treatment has a borderline significance (P = .056). CONCLUSIONS: Early detection of such a life-threatening complication is a key determinant of survival. "Early" does not refer to early postoperative days but means the detection prior to the rupture of the pseudoaneurysm. Postoperative imaging studies such as computed tomographic scan or magnetic resonance cholangiopancreatography early and periodically to follow up the graft status is recommended, especially for those who had received other interventions before or after the liver transplantation.


Subject(s)
Aneurysm, False/diagnostic imaging , Early Diagnosis , Hepatic Artery/diagnostic imaging , Liver Transplantation , Postoperative Complications/diagnosis , Adult , Aged , Aneurysm, False/complications , Aneurysm, False/mortality , Aneurysm, False/therapy , Computed Tomography Angiography , Embolization, Therapeutic , Gastrointestinal Hemorrhage/etiology , Hemobilia/etiology , Humans , Male , Middle Aged , Postoperative Complications/therapy , Stents , Survival Rate , Treatment Outcome , Vascular Surgical Procedures
3.
Transplant Proc ; 47(3): 815-6, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25891737

ABSTRACT

Right diaphragmatic hernia after donor hepatectomy is extremely rare. The occurrence is usually late. We present a case with early occurrence complicated with small bowel strangulation. Early detection and emergency surgical repair relieved the problem quickly. Predisposing factors are discussed. To avoid such a complication is very important.


Subject(s)
Hepatectomy/adverse effects , Hernia, Diaphragmatic/etiology , Adult , Female , Hernia, Diaphragmatic/complications , Hernia, Diaphragmatic/surgery , Humans , Intestinal Diseases/etiology , Liver Transplantation , Living Donors , Time Factors , Tissue and Organ Harvesting/adverse effects
5.
Transplant Proc ; 46(3): 686-8, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24767324

ABSTRACT

BACKGROUND: Despite recent advances in preoperative diagnostic imaging and operative techniques, biliary variation of the donor still remains a challenge in the procurement of graft. The supraportal right bile duct (BD) variant including presentation as trifurcation is a potential trap for injuring the remnant bile duct of donor. METHODS: Before living/related-donor liver transplantation (LRLT), cholangiogram with magnetic resonance images of each donor was performed as a routine. After exploration of the donor before hilar dissection, intraoperative chloangiography (IOC) was routinely performed. Among the supraportal right bile duct variants, if the preoperative cholangiography showed a suspected trifurcation of the bile duct, we then performed 3 sessions of IOC during liver graft procurement, including prior to hilar dissection, before the division of bile ducts and after the division. We reviewed the cholangiogram and the postoperative laboratory data of a consecutive series of 25 donors of LRLT. RESULTS: There was no division injury of the remnant bile duct of all of the donors. CONCLUSIONS: Repeated IOC is suggested as a routine for variants of supraportal right bile ducts especially trifurcation pattern in graft procurement to avoid the injury of donor remnant bile ducts.


Subject(s)
Bile Ducts/anatomy & histology , Cholangiography/methods , Liver Transplantation , Living Donors , Patient Safety , Bile Ducts/injuries , Humans , Intraoperative Period , Magnetic Resonance Imaging
6.
Transplant Proc ; 46(3): 841-4, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24767362

ABSTRACT

BACKGROUND: Intrahepatic segmental portal vein thrombosis after living-related liver transplantation (LRLT) is uncommon. The cause remains unclear. METHODS: After providing written informed consent, 25 recipients receiving LRLT at our institution from January 2011 to September 2013 were enrolled in this study. We performed triphase computerized tomographic (CT) study of the liver graft of each recipient 1 month after LRLT. The patencies of hepatic artery, portal vein, and hepatic vein were evaluated in detail. The triphase CT scans of the liver of each donor before transplantation also were reviewed. Thrombosis of the intrahepatic segmental portal vein was defined as the occlusion site of the portal vein being intrahepatic. Extrahepatic portal vein thrombosis was excluded in this study. RESULTS: Among the 25 patients, 2 (8%) developed thrombosis of intrahepatic segmental portal vein. One 47-year-old man received LRLT for hepatitis B viral infection-related liver cirrhosis (Child-Pugh class C) with 3 hepatocellular carcinomas (total tumor volume <8 cm). Another 53-year-old man received LRLT for alcoholic liver cirrhosis (Child-Pugh class C). Both had developed progressive jaundice and cholangitis 1 month after surgery. Intrahepatic biliary stricture was found on the follow-up magnetic resonance images. However, liver triphase CT study demonstrated occlusion of intrahepatic portal vein of segment 8 in each patient. Radiologic interventions and balloon dilatation therapy via percutaneous transhepatic biliary drainage route improved the symptoms and signs of cholangitis and obstructive jaundice for both. CONCLUSIONS: Thrombosis of intrahepatic segmental portal vein is not common but is usually associated with complications of intrahepatic bile duct. Early detection is important, and follow-up CT study of liver is suggested.


Subject(s)
Liver Transplantation/adverse effects , Living Donors , Portal Vein/pathology , Thrombosis/etiology , Humans , Male , Middle Aged
7.
Transplant Proc ; 46(3): 880-2, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24767371

ABSTRACT

INTRODUCTION: Loss of speech after living-related liver transplantation is uncommon. Either immunosuppressive agents, related sequelae, or a neurological event may cause it. CASE REPORT: A 46-year-old man developed dysarthria and dysphagia on the 10th day after living-related donor liver transplantation for alcoholic cirrhosis with Child-Pugh class C. Brain magnetic resonance images and electroencephalograms could not detect any lesion, but the diffusion tensor image showed a subacute lacunar infarction at right midbrain. The patient's speech improved 1 month after rehabilitation. CONCLUSIONS: Some unexpected neurological events, such as loss of speech, may occur after liver transplantation. The differential diagnosis becomes very important before active treatment. Magnetic resonance imaging supplemented with diffusion tensor imaging is an effective imaging study in establishing the diagnosis.


Subject(s)
Aphonia/etiology , Diffusion Tensor Imaging , Liver Transplantation/adverse effects , Living Donors , Aphonia/pathology , Aphonia/physiopathology , Brain/pathology , Brain/physiopathology , Electroencephalography , Humans , Liver Cirrhosis/surgery , Magnetic Resonance Imaging , Male , Middle Aged
9.
Transplant Proc ; 45(5): 2059-62, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23769108

ABSTRACT

BACKGROUND: Early detection of Budd-Chiari syndrome (BCS) to give the appropriate therapy in time is crucial. Angiography remains the golden standard to diagnose BCS. However, to establish the diagnosis of BCS in complicated cirrhotic patients remains a challenge. We used maximum intensity projection (Max IP) and minimum intensity projection (Min IP) from computed tomographic (CT) images to detect this syndrome in such a patient. CASE REPORT: A 55-year-old man with a history of chronic hepatitis B infection and alcoholism had undergone previously a left lateral segmentectomy for hepatic epitheloid angiomyolipoma (4.6 × 3.5 × 3.3 cm) with a concomitant splenectomy. Liver decompensation with intractable ascites and jaundice occurred 4 months later. The reformed images of the venous phase of enhanced CT images with Max IP and Min IP showed middle hepatic vein thrombosis. He then underwent a living-related donor liver transplantation with a right liver graft from his daughter. Intraoperatively, we noted thrombosis of his middle hepatic vein protruding into inferior vena cava. The postoperative course was unevenful. Microscopic findings revealed micronodular cirrhosis with mixed inflammation in the portal areas. Some liver lobules exhibited congestion and sinusoidal dilation compatible with venous occlusion clinically. CONCLUSIONS: We recommend Max IP and Min IP of CT images as simple and effective techniques to establish the diagnosis of BCS, especially in complicated cirrhotic patients, thereby avoiding invasive interventional procedures.


Subject(s)
Budd-Chiari Syndrome/diagnosis , Liver Cirrhosis/complications , Budd-Chiari Syndrome/complications , Humans , Male , Middle Aged , Tomography, X-Ray Computed
10.
Gene Ther ; 19(1): 25-33, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21562593

ABSTRACT

Chronic hepatitis B virus (HBV) infection is closely related to the development of severe liver complications, including hepatocellular carcinoma. In previous studies, we reported that in vivo long-term HBV suppression in transgenic mice can be achieved without apparent toxicity by short hairpin RNA sequentially delivered using adeno-associated viral (AAV) vectors of different serotypes. Our goal herein was to address the clinical utility of this delivery system and, in particular, to determine whether RNA interference (RNAi) and its ability to induce long-term HBV suppression will modulate the development of HBV-associated liver pathology. As a model system, we used a unique HBV transgenic mouse model, containing a 1.3 times over length of the HBV genome, on the ICR mouse background. These transgenic mice produce high serum HBV titers comparable with human chronic HBV patients, and, importantly, manifest characteristic HBV-associated pathology, including progressive hepatocellular injury and the development of hepatocellular adenoma. Using this system, we injected animals with AAV vectors expressing either HBV-specific or a control luciferase-specific short hairpin RNA and followed animals for a total of 18 months. We report herein that AAV-mediated RNAi therapy profoundly inhibits HBV replication and gene expression, with a significant reduction in hepatic regeneration, liver enzymes and, importantly, the appearance of liver adenomas. Indeed, the therapeutic effect of RNAi correlated with the reduction in HBV titers. Our data demonstrate that appropriately designed RNAi therapy has the potential to prevent formation of HBV-associated hepatocellular adenoma.


Subject(s)
Adenoma, Liver Cell/therapy , Gene Expression Regulation, Viral , Hepatitis B virus/pathogenicity , Liver Neoplasms/therapy , RNA Interference , RNA, Viral/genetics , Adenoma, Liver Cell/blood , Adenoma, Liver Cell/pathology , Adenoma, Liver Cell/virology , Animals , Blotting, Northern , Dependovirus/genetics , Dependovirus/metabolism , Female , Gene Transfer Techniques , Hepatitis B Surface Antigens/analysis , Hepatitis B Surface Antigens/blood , Hepatitis B virus/genetics , Hepatitis B virus/physiology , Hepatitis B, Chronic/blood , Hepatitis B, Chronic/pathology , Hepatitis B, Chronic/therapy , Hepatitis B, Chronic/virology , Hepatocytes/cytology , Hepatocytes/metabolism , Hepatocytes/virology , Humans , Liver Neoplasms/blood , Liver Neoplasms/pathology , Liver Neoplasms/virology , Liver Neoplasms, Experimental , Luciferases/genetics , Luciferases/metabolism , Male , Mice , Mice, Inbred ICR , Mice, Transgenic , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , RNA, Viral/metabolism , Transgenes , Viral Load , Virus Replication
12.
Gene Ther ; 14(1): 11-9, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16929350

ABSTRACT

RNA interference (RNAi) was reported to block hepatitis B virus (HBV) gene expression and replication in vitro and in vivo. However, it remains a technical challenge for RNAi-based therapy to achieve long-term and complete inhibition effects in chronic HBV infection, which presumably requires more extensive and uniform transduction of the whole infected hepatocytes. To increase the in vivo transfection efficiency in liver, we used a double-stranded adeno-associated virus 8-pseudotyped vector (dsAAV2/8) to deliver shRNA. HBV transgenic mice were used as an animal model to evaluate the inhibition effects of the RNAi-based gene therapy. A single administration of dsAAV2/8 vector, carrying HBV-specific shRNA, effectively suppressed the steady level of HBV protein, mRNA and replicative DNA in liver of HBV transgenic mice, leading to up to 2-3 log(10) decrease in HBV load in the circulation. Significant HBV suppression sustained for at least 120 days after vector administration. The therapeutic effect of shRNA was target sequence dependent and did not involve activation of interferon. These results underscore the potential for developing RNAi-based therapy by dsAAV2/8 vector to treat HBV chronic infection, and possibly other persistent liver infections as well.


Subject(s)
Dependovirus/genetics , Genetic Therapy/methods , Hepatitis B virus/physiology , Hepatitis B, Chronic/therapy , RNA Interference , RNA, Small Interfering/administration & dosage , Animals , Cell Line , Genetic Engineering , Genetic Vectors/administration & dosage , Hepatitis B, Chronic/virology , Hepatocytes/immunology , Hepatocytes/virology , Mice , Mice, Transgenic , RNA, Double-Stranded/administration & dosage , Time Factors
13.
J Eur Acad Dermatol Venereol ; 19(6): 747-50, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16268885

ABSTRACT

Rosai-Dorfman disease in soft tissue without nodal disease has been recognized as a distinct clinicopathologic entity. It may represent a diagnostic challenge and the natural history and optimal treatment has not been well clarified. We investigated a patient in whom Rosai-Dorfman disease was confined to the subcutis of the abdominal wall and recurred after incomplete excision. Complete resolution was achieved by wide surgical excision with negative margins. Pathologic examination confirmed the diagnosis of extranodal Rosai-Dorfman disease. The patient is disease-free after 1 year of follow-up. Despite the possibility that spontaneous remission may occur, our results suggest that when anatomically feasible, complete excision can be a treatment option for persistence or recurrence of exclusively extranodal disease. Larger case series and longer follow-up are needed to assess the long-term efficacy in these patients.


Subject(s)
Histiocytosis, Sinus/surgery , Abdominal Wall , Adult , Diagnosis, Differential , Female , Histiocytosis, Sinus/diagnostic imaging , Histiocytosis, Sinus/pathology , Humans , Tomography, X-Ray Computed
14.
Scand J Gastroenterol ; 37(5): 597-601, 2002 May.
Article in English | MEDLINE | ID: mdl-12059063

ABSTRACT

BACKGROUND: Conventional percutaneous procedures for treating patients with recurrent hepatolithiasis associated with complicated intrahepatic biliary strictures require multiple dilation sessions before stone extraction. We modified the approach, reducing the number of dilation sessions required and using newer lithotripsy and irrigation methods. We suggest that the modified procedures are superior to conventional management and demonstrate their utility in clearing hepatolithiasis. METHODS: Percutaneous transhepatic stricture dilation and cholangioscopic lithotripsy were performed to treat patients with right recurrent hepatolithiasis with complicated intrahepatic biliary strictures. Conventional methods were used in 40 patients (Group A). Modified methods, including simplification of tract establishment and stricture dilation and electrohydraulic lithotripsy (EHL) were used in 60 patients (Group B). RESULTS: Group B patients had fewer complications (massive hemobilia: 0% versus 15%, P = 0.0032, cholangitis: 0% versus 17.5%, P=0.0012), tolerated the procedures better (intolerable pain: 0% versus 12.5%, P=0.0087), had a higher rate of success (residual stones: 3.3% versus 20%, P=0.0132; remaining asymptomatic and stone-free: 81% versus 50%, P = 0.0021), a shorter hospital stay (17.8 +/- 4.4 days versus 36.2 +/- 5.5 days, P < 0.001) and lower overall expense (USD 2689 versus USD 3848) than Group A patients. CONCLUSION: We believe that the modified methods are superior to conventional treatment in that they effectively decrease procedural complications and cost, and significantly improve treatment results.


Subject(s)
Bile Duct Diseases/surgery , Bile Ducts, Intrahepatic/surgery , Catheterization/methods , Cholelithiasis/surgery , Endoscopy, Digestive System/methods , Lithotripsy/methods , Postoperative Complications , Adult , Bile Duct Diseases/diagnostic imaging , Bile Ducts, Intrahepatic/diagnostic imaging , Cholelithiasis/diagnostic imaging , Constriction, Pathologic/diagnostic imaging , Constriction, Pathologic/surgery , Female , Humans , Male , Middle Aged , Radiography , Recurrence , Treatment Outcome
15.
Surg Laparosc Endosc Percutan Tech ; 11(3): 170-5, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11444746

ABSTRACT

Percutaneous stricture dilatation and cholangioscopic lithotomy has become a mainstay in the treatment of patients with recurrent hepatolithiasis associated with intrahepatic biliary strictures. In a consecutive series of 125 patients who underwent percutaneous management of recurrent hepatolithiasis from 1987 to 1999, there were 15 patients in whom the procedure failed to clear the stones. A second percutaneous transhepatic route was established for subsequent treatment. A reappraisal of its indications and efficacy was done. Treatment through a second route was helpful for patients with bilateral strictures, angulated duct, difficult strictures, large impacted stones, a subcutaneous jejunal limb, or hemobilia developing in the first route. Strictures remained impacted in 1 of the 15 patients (failure rate, 7%), with the remaining having complete clearance of stones. Cholangitis occurred in two patients; no other complications were encountered. A second percutaneous route is very helpful for the management of complicated hepatolithiasis and biliary stricture.


Subject(s)
Bile Ducts, Intrahepatic/pathology , Bile Ducts, Intrahepatic/surgery , Cholelithiasis/surgery , Adult , Aged , Constriction, Pathologic , Drainage , Female , Humans , Male , Middle Aged , Recurrence , Treatment Failure
17.
Arch Surg ; 135(11): 1329-33, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11074891

ABSTRACT

HYPOTHESIS: Mutant p53 gene has lost its tumor suppression function and is considered to be a very important step in hepatocellular carcinoma development. We propose that the mutant p53 gene plays a role in its invasiveness and prognosis after resection. DESIGN: A case-controlled study. SETTING: A referral center. PATIENTS: Seventy-nine consecutive patients who underwent surgical resection for hepatocellular carcinoma entered this study. INTERVENTION: Tissue sections of resected hepatocellular carcinoma (deparaffinized and rehydrated from formalin-fixed and paraffin-embedded sections) were incubated with antihuman p53 monoclonal antibody and immunostained. The p53 result was scored without prior knowledge of the patients' status. A 10% immunopositivity was regarded as the threshold value. MAIN OUTCOME MEASURE: The immunopositive rate of p53 was 69.6% (55 of 79 patients). The clinical variables (age, sex, associated liver cirrhosis, hepatitis B virus infection, hepatitis C virus infection, serum alpha-fetoprotein, and Child-Pugh class); the histological variables (size, capsule, vascular permeation; grade of differentiation, and multinodularity); and postoperative course (recurrence, tumor-free interval, death, and survival period) were correlated with p53 immunopositivity. RESULTS: From univariate analysis, more patients with p53 positivity were male (92.7 vs 0%) (P<.001); had vascular permeation (80% vs 50%) (P =.007) (odds ratio [OR], 4.0); no complete capsule (83.6% vs 62.5%) (P =.04) (OR, 3.1); and daughter nodules (90.9% vs 70.8%) (P =.04) (OR, 4.1) than patients with negative p53 staining. From multivariate analysis, only sex and vascular permeation remained significant (P =.001 and P =.008, respectively). Although more patients with p53 positivity had tumor recurrence (78% vs 50%) (P =.01) and death (64% vs 33%) (P =. 01), the Cox proportional hazards model showed that p53 overexpression had only weak correlations with tumor-free interval and survival time (P =.09 and P =.08, respectively). CONCLUSIONS: Our results show that the biological behavior of the mutant p53 gene is strongly related to the invasiveness of hepatocellular carcinoma and may also influence the postoperative course. We suggest that the immunopositivity of the mutant p53 gene has a predictive role in the prognosis of patients with resected hepatocellular carcinoma.


Subject(s)
Carcinoma, Hepatocellular/genetics , Genes, p53/genetics , Liver Neoplasms/genetics , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/surgery , Case-Control Studies , Female , Gene Expression/genetics , Humans , Immunoenzyme Techniques , Liver Neoplasms/mortality , Liver Neoplasms/surgery , Male , Middle Aged , Mutation , Neoplasm Invasiveness , Neoplasm Recurrence, Local/epidemiology , Prognosis , Proportional Hazards Models
18.
Surg Laparosc Endosc Percutan Tech ; 10(5): 278-83, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11083209

ABSTRACT

For recurrent hepatolithiasis coexisting with a complicated long-segment intrahepatic biliary stricture, repeated surgeries, balloon dilation of the stricture, and external-internal stenting may still fail to solve the problem. We tried using a Gianturco-Rosch metallic Z internal stent (Wilson-Cook Medical, Inc., Bloomington, IN, USA) with the aid of percutaneous transhepatic cholangioscopy (PTCS) to treat such patients. Eight patients had a Z stent placed through a percutaneous transhepatic biliary drainage tract. Immediately after stent placement, PTCS was inserted via the percutaneous transhepatic biliary drainage route and a part of the wire skirt not firmly anchored in one of the eight patients was detected. It was successfully repositioned using PTCS. Recurrent cholangitis developed in three patients 6, 7, and 30 months, respectively, after stent placement. PTCS was undertaken again through a reestablished percutaneous transhepatic biliary drainage route and revealed sludge in their stent lumens. We cleared it by PTCS. No further cases of cholangitis occurred in later follow-up. PTCS is useful in ensuring adequate stent position, diagnosing and treating the causes of recurrent cholangitis, and prolonging the function of stents.


Subject(s)
Bile Ducts, Intrahepatic/pathology , Cholelithiasis/diagnosis , Cholelithiasis/therapy , Endoscopy, Digestive System , Stents , Adult , Constriction, Pathologic , Female , Humans , Male , Middle Aged
19.
Virology ; 275(2): 398-410, 2000 Sep 30.
Article in English | MEDLINE | ID: mdl-10998339

ABSTRACT

The hepatitis B virus (HBV) genome is known to contain four conserved and overlapped open reading frames (ORFs) encoding the viral core, polymerase (P), surface (S), and X proteins. Whether HBV encodes other proteins has long been a major interest in the field. Using (32)P-labeling of an introduced protein kinase A site attached to the N- or C-terminus of the HBV polymerase gene, a 43-kDa P-S fusion protein was detected in cell lysate, secreted virions, and 22-nm subviral particles. Immunobiochemical studies showed that the 43-kDa protein contains the epitopes of the N-terminus of polymerase and most parts of the surface proteins. This 43-kDa protein was shown to be a glycoprotein, similar to the surface protein. RT-PCR and sequence analyses identified a spliced mRNA which was derived from pregenomic RNA with a deletion of 454 nucleotides (nt) from nt 2447 to 2902. This splice event creates a P-S fusion ORF. This finding is consistent with the result obtained from an immunobiochemical study. Mutations at the splice donor or acceptor site on the HBV genome abrogated the production of the 43-kDa protein. These mutants had no effect on viral replication in transfected HuH-7 cells. However, this P-S fusion protein is able to substitute for the LS protein in virion maturation. On the basis of these results, we conclude that the 43-kDa protein is a polymerase-surface fusion protein encoded by a spliced RNA. Similar to the LS protein, the 43-kDa P-S fusion protein is a structural protein of HBV and might play a role in the HBV life cycle.


Subject(s)
Hepatitis B virus/genetics , RNA Splicing , Viral Fusion Proteins/genetics , Viral Structural Proteins/genetics , Aspartic Acid Endopeptidases/genetics , Cell Line , Electrophoresis, Polyacrylamide Gel , Epitopes , Gene Products, pol/genetics , Glycoproteins/genetics , Glycoproteins/metabolism , Glycosylation , Hepatitis B Surface Antigens/genetics , Hepatitis B virus/metabolism , Humans , Molecular Weight , Open Reading Frames , Precipitin Tests , Reverse Transcriptase Polymerase Chain Reaction , Viral Fusion Proteins/metabolism , Viral Structural Proteins/metabolism
20.
J Virol ; 74(19): 9010-8, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10982345

ABSTRACT

Accurate translocation of the polymerase-linked oligomer to the acceptor site (DR1*) in reverse transcription is crucial for maintaining the correct size of the hepatitis B virus (HBV) genome. Various sizes of foreign sequences were inserted at different sites of the HBV genome, and their effects on accurate translocation of polymerase-linked oligomer to DR1* were tested. Three types of replicate DNA products were observed in these insertion mutants: RC (relaxed circle) and type I and type II DL (duplex linear) DNA. Our results indicated that the minus strand of RC and type I DL form was elongated from DR1*, while the minus strand of the type II DL form was elongated from multiple internal acceptor sites (IAS), such as IAS2. These IASs were also found to be used by wild-type HBV but with a very low frequency. Mutation of IAS2 by base substitution abrogated polymerase-linked oligomer transferring to IAS2, demonstrating that base pairing also plays an important role in the function of IAS2 as a polymerase-linked oligomer acceptor site. Data obtained from our insertion mutants also demonstrate that the distance between the polymerase-linked oligomer priming site and the acceptor is important. The polymerase-linked oligomer prefers to translocate to an acceptor, DR1* or IAS2, which are ca. 3.2 kb apart. However, it will translocate to both DR1* and IAS2 if they are not located 3.2 kb apart. These results suggest that the polymerase-linked oligomer may be able to scan bidirectionally for appropriate acceptor sites at a distance of 3.2 kb. A model is proposed to discuss the possible mechanism of polymerase-linked oligomer translocation.


Subject(s)
Genome, Viral , Hepatitis B/genetics , Translocation, Genetic , Animals , DNA-Directed DNA Polymerase/genetics , Dimerization , Phosphoproteins/genetics , Transcription Factors/genetics
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