[Chologenic abscess after radiofrequency ablation of a cholangiocellular carcinoma]

HISTORY

Persistent fever occurred after palliative radiofrequency thermal ablation (RFTA) of a solitary liver metastasis in a 62-year-old patient with cholangiocarcinoma treated by cholecystectomy, lymph-adenectomy, resection of the ductus hepatocholedochus and biliodigestive anastomosis.

INVESTIGATIONS AND DIAGNOSIS

Tests for inflammatory disease were elevated. Sonography revealed an echo-free lesion in the region of the previous RFTA. Percutaneous drainage produced purulent material.

TREATMENT AND COURSE

The liver abscess communicating with the bile duct system was drained and treated with antibiotics.

CONCLUSION

A liver abscess is a rare complication of RFTA. A preexisting biliodigestive anastomosis may be an independent risk factor for this rare complication.

[Hepatocellular carcinoma. Pathogenesis and multicentricity]

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in some areas of the world, with an extremely poor prognosis. The clinical and molecular pathogenesis of HCC is very complex and involves alterations in the structure or expression of several tumor suppressor genes, oncogenes and, possibly, mechanisms leading to genetic instability due to mismatch repair deficiency or chromosomal instability and aneuploidy due to defective chromosomal segregation. Central to the molecular pathogenesis of HCC are mutations of various genes and a genetic instability which, in most cases, result from chronic liver disease and the associated enhanced liver cell regeneration and mitotic activity. The prognosis is generally very poor. Most studies report a 5-year survival rate of less than 5% in symptomatic HCC patients. Therapeutic strategies include resection, liver transplantation, and nonsurgical interventions such as percutaneous ethanol injection, radiofrequency thermal ablation, transarterial embolization, and chemoembolization. HCC has been shown to be quite resistant to radio- and chemotherapy.

[Molecular virology of hepatitis C]

Hepatitis C virus (HCV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Here, we will briefly review current concepts of the molecular virology of hepatitis C. In vitro and in vivo models of HCV replication will be discussed in this context. Finally, novel antiviral strategies will be outlined that result from an improved understanding of the viral life cycle.

[Transgenic plants]

Advances in molecular genetics and recombinant DNA technology have revolutionized our understanding of the pathogenesis as well as the diagnosis, therapy and prevention of human diseases. Similar developments characterize plant biotechnology with the production of plant derived biomedical as well as health products. Apart from the fundamentals of molecular plant genetics, the production of transgenic plants as well as the clinical relevance, benefits, limitations and potential problems of plant biotechnology will be reviewed in some detail. It is a particular challenge to physicians in an increasingly informed environment to be informed about the new developments in molecular biology and recombinant DNA technology and to have a qualified opinion about their clinical relevance.

[Molecular diagnostic tools in gastroenterology]

Molecular biology has become an integral part of modern medicine. Novel molecular methods have yielded great progress in early detection, classification and management of a variety of diseases. This review discusses principles and applications of molecular diagnostic tools in the field of gastroenterology.

[Prevention of hepatocellular carcinoma]

Prevention is an increasingly important area of modern medicine. One of the foremost goals in the field of hepatology is prevention of hepatocellular carcinoma since this tumor has a poor prognosis and current therapeutic options are limited. Most hepatocellular carcinomas arise from chronic liver disease and liver cirrhosis which is considered a major risk factor for tumor development. The most common etiologic factors causing liver cirrhosis include chronic viral hepatitis, alcohol consumption, toxins and a few metabolic disorders. This review discusses current therapeutic concepts for prevention and treatment of chronic liver disease and cirrhosis.

[Nonsurgical therapy of hepatocellular carcinoma]

Several non-surgical local ablation methods for the treatment of hepatocellular carcinoma (HCC) have been developed. Among them, percutaneous ethanol injection is worldwide an accepted alternative to surgery in patients with small HCCs. Other local minimal-invasive treatment options, like one time radio-frequency thermal ablation seem to result in more effective tumor control. Randomized controlled trials showed no survival benefit after transarterial chemoembolization and its variants for the treatment of local advanced HCCs. Combined therapeutic strategies may play an increasing role in future in these cases. Effective chemotherapy is not available for metastasized or advanced HCCs. The role of novel techniques for the treatment of HCC has to be carefully determined in large controlled clinical studies.

[Cholangiocarcinoma]

Cholangiocarcinomas (CCC) are rare tumors with an incidence of 2-4/100,000 per year. They are a heterogeneous group of neoplasias that include the most common perihilar or Klatskin tumor (60%), the intrahepatic (peripheral) CCC, the extrahepatic bile duct cancer, the gallbladder cancer and the cancer of the ampulla of Vater. At the time of diagnosis only 20% of patients can be treated by surgery, that offers the only chance for cure. Due to high recurrence rates liver transplantation is not indicated. Patients with advanced unresectable carcinoma have a dismal prognosis with an overall survival rate of only 6-8 months. Neither chemotherapy nor radiation therapy improves survival. In patients not eligible for curative surgery prevention or treatment of cholestatis is the main objective. This can be achieved endoscopically, percutaneously or by surgical biliodigestive anastomosis. Palliative chemotherapy results in response rates up to 20%. The most frequently used agents are 5-FU and Gemcitabine that can be combined with external or internal radiation. By combining different treatment modalities significant survival can be achieved in some patients. Evidence Based Medicine studies are needed before treatment strategies can be recommended for clinical practice.

[Therapy of hepatitis C]

Hepatitis C virus (HCV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Here, we will briefly review current and evolving therapies for chronic hepatitis C. Standard therapy with (pegylated) interferon-alpha and ribavirin achieves sustained response rates of up to about 40% in genotype 1- and about 80% in genotype 2- and 3-infected patients. Recent progress in the molecular virology and pathogenesis of hepatitis C has allowed the identification of novel antiviral targets and therapeutic strategies. These will likely complement existing therapeutic modalities in the near future.

Radiofrequency thermal ablation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide. Due to advanced or decompensated liver cirrhosis, comorbidity and multicentricity of the tumor lesions, 70-80% of HCC patients are inoperable at the time of diagnosis. Radiofrequency thermal ablation (RFTA) is a new minimally invasive and sage technique for the nonsurgical treatment of HCCs. Similar to other ablation techniques, the treatment strategy depends on several factors, including the patient's clinical status, the stage of liver cirrhosis and of the HCC. RFTA can be performed percutaneously, laparoscopically or after laparotomy. Advanced RFTA equipment, refined techniques of modifying tumor tissue response to RFTA, and combined treatment strategies should lead to better response rates even in larger HCCs.

Inhibition of duck hepatitis B virus replication by intrahepatic expression of an antiviral resistance gene

Resistance genes coding for inhibitors of hepadnaviral replication, such as ribozymes, antisense RNA, and dominant negative mutants have been shown to be effective in transfected hepatoma cells. In vivo studies, however, are not available to date. Here we expanded the use of the duck hepatitis B virus (DHBV) model for studying antiviral resistance genes in vivo. Animals were experimentally infected by intravenous injection of DHBV-positive serum in ovo. The use of recombinant human adenovirus type 5 and avian adenovirus CELO for gene transfer was evaluated. Adenovirus type 5 transduced more than 95% and CELO less than 1% of embryonic hepatocytes in vivo. Adenovirus type 5 interfered with DHBV replication (viral cross-talk), but this effect was moderate and did not preclude analysis of specific antiviral effects. Thus adenoviral transfer of a dominant negative mutant prior to DHBV infection (intracellular immunization) yielded 100-fold suppression of viral replication compared to the green fluorescent protein marker gene. Neither gene was toxic. These data demonstrate that a prototype anthepadnaviral resistance gene is functional in vivo. Duck embryos represent a useful model for evaluating gene therapeutic strategies in vivo without the need for large scale preparations of gene delivery vehicles.