PubMed Health⌕ Search

Biomedical subjects

W J Hofmann

Publications and source records attributed to W J Hofmann.

At least 55 records · Page 3Linked to original sources
PubMed1996

A rapid and highly specific technique to detect hepatitis C RNA in frozen sections of liver.

AIMS: To develop a polymerase chain reaction (PCR) based technique that would permit the rapid and highly specific detection of hepatitis C virus (HCV) RNA extracted from frozen liver tissue. METHODS: Samples of liver tissue from 18 patients undergoing orthotopic liver transplantation were studied. Nine patients were HCV positive. Total RNA was extracted from between one and 10 sections, 10 microns thick, from each tissue sample. HCV RNA was amplified by (1) conventional, multistep reverse transcription PCR (RT-PCR) and by (2) combined, single step RT-PCR using coupled oligonucleotide primers based on the sequence of the 5' untranslated region of the viral genome. Positive results were confirmed by dot blot analysis using a digoxigenin labelled oligoprobe (Alx 89). RESULTS: HCV RNA was detected in the nine HCV positive patients by both conventional and combined RT-PCR. HCV RNA was not detected in the HCV negative patients. As little as 500 ng total RNA was needed as the template to yield detectable amounts of amplified cDNA. The digoxigenin labelled oligoprobe hybridised with HCV RNA positive specimens only. CONCLUSIONS: The combined, single step RT-PCR is a rapid and sensitive technique for detecting HCV RNA in frozen liver tissue.

Base Sequence↗
PubMed1995

Involvement of the CD95 (APO-1/Fas) receptor and ligand in liver damage.

Apoptosis occurs in the normal liver and in various forms of liver disease. The CD95 (APO-1/Fas) (CD95) receptor mediates apoptosis, and liver cells in animal models are acutely sensitive to apoptosis initiated by this receptor. We have used primary human hepatocytes as a model system to investigate CD95-mediated apoptotic liver damage. Treatment of fresh human hepatocytes with low concentrations of agonistic antibodies against CD95 resulted in apoptosis of > 95% of the cultured liver cells within 4 and 7.5 h. Immunohistology of a panel of explanted liver tissues revealed that hepatocytes in normal livers (n = 5) and in alcoholic cirrhosis (n = 13) expressed low constitutive levels of CD95. CD95 receptor expression was highly elevated in hepatocytes in hepatitis B virus-related cirrhosis (n = 9) and in acute liver failure (n = 8). By in situ hybridization CD95 ligand messenger RNA expression was absent in normal liver but detected at high levels in livers with ongoing liver damage. In cases of hepatitis B virus-related cirrhosis and acute hepatic failure, ligand expression was found primarily in areas with lymphocytic infiltration. In contrast, in patients with alcoholic liver damage, high CD95 ligand messenger RNA expression was found in hepatocytes. These findings suggest that liver destruction in hepatitis B may primarily involve killing of hepatocytes by T lymphocytes using the CD95 receptor-ligand system. In alcoholic liver damage, death of hepatocytes might occur by fratricide and paracrine or autocrine mechanisms mediated by the hepatocytes themselves.

Antibodies, Monoclonal↗
PubMed1995

Melanotic paraganglioma of the posterior mediastinum.

A melanotic paraganglioma occurred in a 57-year-old woman, located in the left paravertebral space of the upper mediastinum. It was totally resected. During a 5 year follow up period neither tumour recurrence nor metastasis were observed. Histological examination of the tumour revealed a paraganglioma with monomorphous chief cell like elements which were arranged in a "zellballen" pattern. Immunohistochemical results also were in accordance with the diagnosis since neuron-specific enolase, chromogranin and synaptophysin were found in tumour cells whereas keratin was not. Additionally, neurosecretory granules were found in tumour cells during electron microscopy. A peculiar feature of the tumour was its strong pigmentation due to melanin located within the tumour cells and tumour associated melanophages. The simultaneous expression of functional properties of two different neural crest derived cells in one tumour stresses the close relationship between all neural crest elements and is in accordance with the observation of other melanotic, non-melanomatous tumours.

Cytoplasmic Granules↗
PubMed1995

[Ischemic type lesions of the bile ducts after liver transplantation: 2 years results].

Ischemic type lesions (ITL) after orthotopic liver transplantation are characterized by bile duct necroses leading to alterations of the ductal lumen, biliary leakage, cast formation and, thereby, to cholestasis. After exclusion of causative factors, such as arterial thrombosis, ABO incompatibility and chronic rejection, ITL occurred in 21 of 165 patients. The rate of ITL after UW preservation was higher (25%) in grafts preserved for > 10 hours in comparison to < 10 hours (7%; p < 0.05). Treatment consisted of endoscopic and percutaneous intervention, surgical revision and retransplantation. Retransplantation is indicated in many patients with lesions of extra- and intrahepatic bile ducts (type A). Other methods are of palliative character and may only be successful in type B (extrahepatic) lesions. Morbidity in patients with ITL is considerable. In comparison to patients without ITL, mortality, however, is not increased.

Bile Ducts↗
PubMed1995

[Pathology of the explanted liver in liver transplantation].

The primary diseases of 209 explanted livers of the transplantation center of the University of Heidelberg are presented. Liver cirrhosis was found in 48.8% as the primary disease followed by the group of malignancies of the liver (28.2%) with HCC as the predominant tumor. Fulminant liver failure was found in 13.8% as the primary disease. Metabolic disorders comprised a small group of 11 cases (5.3%). 7 cases were transplanted for Budd Chiari syndrome (3.3%) and one case was transplanted for E. alveolaris. The examination of fulminant viral hepatitis revealed evidence of the involvement of the APO-1/Fas (CD95) system in the pathogenesis of this disorder. Prognostic factors for recurrence of hepatocellular carcinoma are size and number of tumor nodules as well as proliferative activity of the tumors determined by Ki67 immunostaining. Diagnosis of HCV infection of the livers is best established by RT-PCR after RNA extraction and is still superior to other immunohistochemical or in-situ methods.

Analysis of Variance↗
PubMed1994

Effect of ursodeoxycholic acid on liver and bile duct disease in primary sclerosing cholangitis. A 3-year pilot study with a placebo-controlled study period.

Primary sclerosing cholangitis is a cholestatic disease of the liver characterized by progressive fibrotic inflammation and obliteration of the extra- and/or intrahepatic bile ducts. There is no effective therapy. We, therefore, studied the safety and efficacy of ursodeoxycholic acid in patients with primary sclerosing cholangitis with or without additional ulcerative colitis. In a 1-year ursodeoxycholic acid treatment period, which preceded the controlled study period, ursodeoxycholic acid was well tolerated in 22 of 24 patients with ulcerative colitis and in all three patients without ulcerative colitis. In two patients with ulcerative colitis the dose of 750 mg ursodeoxycholic acid/day led to diarrhea, but following reduction of the dose to 500 and 250 mg/day ursodeoxycholic acid was well tolerated. After 1 year of ursodeoxycholic acid treatment, 20 patients were randomly assigned to receive either ursodeoxycholic acid 750 mg/day or placebo. All of them finished a double-blind, placebo-controlled study period. During ursodeoxycholic acid treatment, the liver enzymes improved markedly. The difference in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and gamma-glutamyltransferase between the placebo and ursodeoxycholic acid group was significant (p < 0.05). Following ursodeoxycholic acid treatment, pruritus and fatigue improved in half of the patients but the difference between the placebo and ursodeoxycholic acid group was not significant. According to the ethical guidelines, after 3 months of placebo treatment, the controlled study had to be discontinued because of a more than twofold increase of serum transaminases in 8/10 patients on placebo. After the end of the controlled study, all patients were continuously treated with ursodeoxycholic acid for up to 4 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

p53 overexpression is frequent in European hepatocellular carcinoma and largely independent of the codon 249 hot spot mutation.

Mutations in the p53 tumour suppressor gene have been recently described in hepatocellular carcinomas (HCC) from high risk areas such as China and South Africa. Our study was designed to assess the importance of p53 aberrations in HCCs from Europe, where the major risk factors in hepatocarcinogenesis, aflatoxin exposure and chronic hepatitis B virus (HBV) infection, do not play a dominant role. We investigated 22 HCCs and, as controls, their corresponding tumour-free liver tissues, seven livers with primary biliary cirrhosis and four morphologically normal livers. p53 overexpression, which is usually associated with point mutations of the p53 gene, was detected in 10 of the 22 HCCs by immunoblotting and immunohistochemistry. p53 expression was restricted to the nucleus in the positive cells, while all cells in the control tissues were negative. There was no obvious etiological preference in the p53 positive tumours. Particularly, underlying chronic HBV infection did not appear to be associated with an increased rate of p53 overexpression in European HCCs. SSCP and sequence analysis of exons 5-8 of the p53 gene revealed point mutations in six out of eight tumours with increased steady state levels of p53. In conclusion, our study demonstrates increased p53 levels due to point mutations in a significant proportion of European HCCs. The codon 249 mutation, which was detected in one of the cases, is not predominant in these tumours.

Adult↗
PubMed1993

The humoral immune response to p53 in patients with hepatocellular carcinoma is specific for malignancy and independent of the alpha-fetoprotein status.

Recently, p53 gene aberrations have been recognized as a relevant factor in hepatocarcinogenesis, in tumors from both high-risk and low-risk areas. Because p53 gene mutations typically result in increased p53 levels in tumor cells, this cellular protein might become immunogenic during tumor development. To test this hypothesis, we have analyzed sera from 80 European patients with hepatocellular carcinoma for the presence of p53 antibodies. For this purpose we developed an immunoblot assay using recombinant p53 as antigen. Sixty-seven sera from patients with different acute and chronic liver diseases were used as controls. In addition, serum alpha-fetoprotein assays were performed. Circulating antibodies against p53 were found in 25% (20 of 80) of the sera from patients with hepatocellular carcinoma but not in various nonmalignant liver diseases. The association of p53 antibodies with malignancy was highly significant (p < 0.00003). In 73.8% (59 of 80) of the hepatocellular carcinoma sera the alpha-fetoprotein levels were elevated. Among the 21 alpha-fetoprotein-negative hepatocellular carcinoma sera, 5 were found to contain p53 antibodies (23.8%). In conclusion, an antibody response against p53 developed in a significant proportion of patients with hepatocellular carcinoma but not in those with nonmalignant liver diseases. Serological testing for p53 antibodies gives the opportunity to identify a subgroup of patients with hepatocellular carcinoma not detected by conventional tests for serum alpha-fetoprotein.

Adult↗
PubMed1992

[Liver transplantation after trans-jugular intrahepatic portosystemic stent shunt].

Every third patient with parenchymal liver disease bleeds from esophageal varices. Treatment of this complication is of special interest with regard to liver transplantation which may become necessary later on. The mesocaval H-shunt excluded, surgical shunting results in technical and hemodynamic problems during transplantation. They may be avoided by the new approach of transjugular intrahepatic portosystemic stent shunt (TIPSS). We report our experience with liver transplantation in two patients after TIPSS.

Adult↗
PubMed1991

Rapid intracellular pathway gives rise to cell surface expression of the MHC class II-associated invariant chain (CD74).

In previous investigations, it had been shown that class II and associated invariant polypeptides are sorted to an endocytic route where transport is delayed. Invariant chain (Ii) is degraded in a post-Golgi compartment, presumably an endosomal vesicle, and only class II molecules emerge on the cell surface. By using a mAb against the extracytoplasmic domain of human Ii, we demonstrate, by electron microscopy and by cytofluorometry, surface expression of Ii on lymphoma cells and on human B lymphocytes. We examined surface expression of Ii upon inhibition by brefeldin A of intracellular transport from the endoplasmic reticulum to the Golgi stack. This treatment rapidly depletes the cell surface of Ii. In the subsequent absence of brefeldin A, Ii appears rapidly at the cell surface. Within 5 h, the previous level of surface Ii (sIi) is reconstituted. Chloroquine abrogates depletion of sIi by brefeldin A, apparently by inhibition of internalization of sIi. Because on its route to the cell surface Ii is not proteolytically digested, it was possible that Ii and associated class II molecules are not separated on this pathway. Immunochemical studies reveal that on the cell surface of a B lymphoma cell line a proportion of Ii and class II polypeptides are associated.

Antigens, Differentiation, B-Lymphocyte↗