Biomedical subjects
Publications and source records attributed to T Berg.
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In normal rat and human, most of the nuclei of hepatic parenchymal cells are centrally located in the cytoplasm. However, it is reported that the nuclei of hepatic parenchymal cells are situated at a deviated position on sinusoidal surfaces under pathological situations such as chronic hepatitis, hepatocellular carcinoma, adenomatous hyperplasia, or regeneration. During a study on the mechanism of extreme vitamin A-accumulation in hepatic stellate cells of arctic animals including polar bears, arctic foxes, bearded seals, and glaucous gulls, we noticed that these arctic animals displayed the nuclear deviation in hepatic parenchymal cells on sinusoidal surfaces. In this study, we assessed the frequency of hepatic parenchymal cells showing the nuclear deviation on the sinusoidal surfaces in arctic animals. A significantly higher frequency of the nuclear deviation in hepatic parenchymal cells was seen in polar bears (89.8+/-3.4%), arctic foxes (68.6+/-10.5%), bearded seals (63.6+/-8.4%), and glaucous gulls (24.2+/-5.8%), as compared to that of control rat liver (9.8+/-3.5%). However, no pathological abnormality such as fibrosis or necrosis was observed in hepatic parenchymal and nonparenchymal cells of arctic animals, and there were no differences in the intralobular distribution of parenchymal cells displaying the nuclear deviation in the livers from either arctic animals and control rats. The hepatic sinusoidal littoral cells such as stellate cells or extracellular matrix components in the perisinusoidal spaces may influence the nuclear positioning and hence the polarity and intrinsic physiological function of parenchymal cells.
The sequence variability within the core- and non-structural 5 (NS5)-region of the hepatitis C virus (HCV) was investigated in tumor and non-tumor tissue of 8 patients with HCV-associated hepatocellular carcinoma (HCC). Analyses of multiple clones containing polymerase chain reaction-amplified HCV sequences revealed a significantly higher variability within the core-region of tumor tissue isolates than of isolates from non-tumor tissue. Mutant sequence diversity ranged from silent mutations, as well as amino acid substitutions, appearance of in frame stop codons and deletions leading to frame-shifts. In contrast, the variability of the NS5-region sequences between isolates from tumor and non-tumor tissue was not significantly different. These observations might have important implications on the pathology of HCV, especially its potential tumorigenicity.
Human surfactant protein-A (SP-A) has been purified from a proteinosis patient and characterised by a combination of automated Edman degradation and mass spectrometry. The complete protein sequence was characterised. The major part of SP-A was shown to consist of SP-A2 gene product, and only a small amount of SP-A1 gene product was shown to be present. A cysteine extension to the N-terminal was indicated by sequence data, but was not definitely proven. All proline residues in the Y position of Gly-X-Y in the collagen-like region were at least partially modified to hydroxy-proline, but no lysine residues were found to be modified. A complex N-linked glycosylation was found on Asn-187 showing great heterogeneity as variants from a mono-antennary to penta-antennary glycosylation with varying amounts of attached pentose were identified. The disulfide bridges in the carbohydrate recognition domain were identified to be in the 1-4, 2-3 pattern common for collectins. Interchain disulfide bridges were discovered between two Cys-48 residues and cysteine residues in the N-terminal region. However, the exact disulfide bridge connections within the bouquet-like ultrastructure could not be established.
Distribution of liposome-encapsulated [(125)I]iodixanol in different types of liver cells following intravenous injection was studied in rats. The data showed that liposome-encapsulated [(125)I]iodixanol was rapidly taken up by the liver; after 15 min, radioactivity corresponding to nearly 25% of the injected radioactivity could be recovered therein. After 4 hr, approximately 60% of the injected radioactivity was in the liver. One week after injection, nearly 30% of the encapsulated radioactivity could still be recovered in the liver. Liposome-encapsulated [(125)I]iodixanol was taken up both by hepatocytes and the Kupffer cells. On a per cell basis, the uptake of liposome-encapsulated [(125)I]iodixanol in Kupffer cells was more than 10-fold greater than that in hepatocytes, while the contribution of liver endothelial cells to uptake was negligible. Osmotic protection studies showed that iodixanol does not readily diffuse across lysosomal membranes, indicating that loss of iodixanol from the liver probably occurred by recycling rather than by diffusion across phagolysosomal and plasma membranes.
Resistance formation is a major problem in antiviral treatment of hepatitis B recurrence after liver transplantation. One possible therapeutic approach is an antiviral combination therapy with synergistic drugs. Four patients who were transplanted for chronic hepatitis B were analyzed retrospectively. All patients had reinfection of the graft and breakthrough of hepatitis B virus (HBV) during consecutive famciclovir and lamivudine monotherapy. Subsequently a combination therapy of lamivudine and interferon alpha 2a (3 times 3 million units weekly) was initiated. Addition of interferon markedly reduced viral replication rate in all patients. Three patients became HBV-DNA negative despite lamivudine resistance, but only two had a sustained response. No patient seroconverted to anti-HBe or lost HBsAg, but all patients showed a normalization of alanine aminotransferase and aspartate aminotransferase levels. No severe complications, and especially no rejection episodes occurred. Therefore lamivudine combined with interferon might be used for the therapy of hepatitis B reinfection after liver transplantation.
Phagocytosis of microorganisms and other particles is mediated most efficiently by receptors such as Fc-receptors (FcR) and complement-receptors (C3R). Interaction between these receptors and ligands on the particle results in signal transduction events that lead to actin polymerisation and phagosome formation. The phagosome then undergoes a maturation process whereby it transforms into a phagolysosome. Phagosome maturation depends on interactions (fusion events) with early and late endosomes as well as with lysosomes. The fusion processes are regulated by small GTP-binding proteins and other proteins that are also involved in fusion processes in the endocytic pathway. Although most phagocytosed microorganisms are killed in the lysosome, some pathogens have developed survival strategies and are able to live in the harsh conditions in the phagolysosome or interfere with the maturation process and thereby evade destruction by acid hydrolases.
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Development of resistance is a major issue in antiviral treatment of hepatitis B reinfection after liver transplantation. Antiviral combination therapy is discussed for therapy or prevention of this breakthrough of viral replication. Eight patients were enrolled into this retrospective analysis after liver transplantation for chronic hepatitis B infection. All had reinfection of the graft and breakthrough of HBV during consecutive famciclovir and lamivudine monotherapy. Subsequently a combination therapy with lamivudine and interferon-alpha 2a (group I, n = 4) or lamivudine and famciclovir (group II, n = 4) was initiated. Combination therapy was started 61 months (group I) and 25 months (group II) after liver transplantation. It markedly reduced the viral replication rate in all patients despite lamivudine resistance. In group I three of four patients and in group II two of four patients became HBV-DNA negative. Two long-term responders were observed in group I, and none in group II. No patient became HBsAg negative or lost HbeAg. Pretreatment elevated ALT and AST levels were significantly reduced. No severe complications, and especially no rejection episodes, occurred. Lamivudine in combination with other antiviral agents, especially interferon-alpha, might be a therapeutic option for hepatitis B reinfection after liver transplantation. Suppression of virus replication to the point of undetectable values is possible even in patients with lamivudine-resistant virus mutations.
Lamivudine and famciclovir have expanded therapeutical options for HBV infection after liver transplantation. First studies confirm good antiviral effects of both, but at present the major problem seems to be a rapid resistance formation in immunosuppressed patients. Thirty-four adult patients with HBV recurrence despite passive immunoprophylaxis and seven with de novo infection after orthotopic liver transplantation (OLT) were treated with 100-150 mg lamivudine daily. Patients were either treated directly after infection (n = 14) or after breakthrough of viral replication during an initial famciclovir therapy (n = 27). All patients except two responded to treatment with a reduction of serum HBV-DNA of over 50%. Thirty-one patients (76%) turned HBV-DNA-negative during lamivudine therapy. Viral breakthrough was observed in 14 of these patients after 4-13 months of treatment. A total of 17 patients (40%) remained HBV-DNA-negative for more than 12 months. Only nine patients eliminated HBsAg, of which four had and an HDV coinfection. None of the HBeAg-positive patients converted to anti-HBe. Most patients showed a prompt and significant reduction of aspartate aminotransferase (ALAT) levels. No severe complications occurred. Therefore, a safe and effective therapy of HBV infection after transplantation is possible with lamivudine. Viral replication is suppressed even in patients who revealed breakthrough during famciclovir therapy. Resistance formation as a major drawback occurred in one third of the patients within the first year of treatment.
The response of human granulocytes to polystyrene latex beads of diameter 0.1-7 microm was measured by luminol-dependent chemiluminescence. In all instances, the response to beads of 3-7 microm was definitely higher than with smaller beads. In protein-free medium, the chemiluminescence response was slow compared to that of opsonized zymosan, and the highest response was only 9% of the response to opsonized zymosan. Scanning electron microscopy showed that granulocytes in suspension bound the particles, occasionally by extending rope-like protrusions. When the beads were coated with albumin, the chemiluminescence diminished to about 1/3 of that seen with uncoated beads; however, preincubating the beads in serum led to a large increase with beads of 1.1 microm (to 25% of the maximal response to opsonized zymosan) and 3.19 microm (to 42%), but with the smallest beads, no increase was noted. "Priming" of the cells with tumor necrosis factor-alpha caused a further increase with serum-coated beads. When uncoated beads of 1.1 microm were tested with "primed" cells, there was an increase of 6 times in the chemiluminescence compared to un-"primed" cells.
BACKGROUND: Combination therapy with interferon alpha (IFNalpha) plus ribavirin has been shown to improve the sustained response rate in patients with chronic hepatitis C but there is little information regarding the lengths of time for this therapeutic regimen. In this study we therefore tried to evaluate whether the analysis of different virological parameters could provide new clues with respect to the early determination of the efficacy of this form of combination therapy. Furthermore, we also examined whether short-term induction combination therapy followed by IFNalpha alone is more effective than monotherapy in mounting an initial as well as a sustained virological response. METHODS: 185 patients with histologically proven chronic hepatitis C (mean age 42 years (range 19-65 years); 110 males, 75 females) were enrolled in the study. The patients were randomly assigned to receive, over the first 12 weeks, either interferon alpha 2a 6 million units (MU) three times weekly plus ribavirin 14 mg/kg per day (n=93) or the same dose of IFNalpha alone (n=92). Patients with a virological response (serum HCV RNA undetectable) after 12 weeks were subsequently treated with 3 MU IFNalpha alone thrice weekly for a further 40 weeks. Otherwise, treatment was discontinued. After the end of treatment, patients were followed up for 24 weeks. RESULTS: Patient characteristics at baseline were not significantly different in the two treatment groups. An initial virological response at week 12 was seen in 61 (66%) patients receiving IFNalpha plus ribavirin and in 44 (48%) being treated with IFNalpha alone (p=0.015) and this improvement in the response rate was mainly restricted to HCV genotype 1-infected patients (58% vs. 38%). In contrast, end-of-treatment (week 52) and sustained virological response rates were similar in both groups (37% vs. 29% and 26% vs. 17% [p=0.1], respectively). Interestingly, patients with HCV genotype 3, however, clearly benefited from short-term combination therapy. Thus, sustained virological response rates in these patients significantly increased from 25% (IFNalpha monotherapy) to 59% (combination therapy) (p=0.05). CONCLUSIONS: Short-term combined therapy for 12 weeks is more effective than the monotherapy with respect to the induction of an initial virological response but this effect applies only to genotype 1-infected patients. However, there is no significant difference between both therapeutic schedules with regard to the induction of sustained response. Although HCV genotype 3-infected patients seem to benefit from this short-term combined therapy, prolonged combined therapy may be necessary in HCV genotype 1-infected patients.
Although the antiviral effects of amantadine sulphate (1-aminoadamantan sulphate) have not been characterized for the hepatitis C virus (HCV), previous pilot studies have suggested promising results in patients with chronic hepatitis C. The aim of the present study was to compare the efficacy, safety, and health-related quality of life (HRQOL) of interferon alfa (IFN-alpha) alone or in combination with oral amantadine for treatment of chronic hepatitis C. One hundred nineteen previously untreated patients with chronic hepatitis C were randomly allocated to treatment with IFN-alpha2a at a dose of 6 megaunits 3 times a week subcutaneously for 24 weeks, followed by 3 megaunits thrice weekly for an additional 24 weeks plus amantadine sulphate administered orally 100 mg twice a day for 48 weeks or the same IFN regimen plus a matched placebo. The primary endpoint was undectable serum HCV RNA (<1,000 copies/mL) at week 24 after treatment. At the end of treatment and the 24-week follow-up period serum HCV RNA was undetectable in 20 (34%) and 6 (10%) of the 59 patients treated with the combination IFN-alpha plus amantadine and in 20 (33%) and 13 (22%) of the 60 patients treated with IFN-alpha alone, respectively (P = n.s.). Discontinuation of therapy for adverse events was similar in both treatment groups. Although treatment with IFN-alpha worsened HRQOL, combination with amantadine showed a substantial trend to improve fatigue and vigor. In conclusion, combination therapy IFN-alpha plus amantadine is as effective as IFN-alpha monotherapy in previously untreated patients with chronic hepatitis C.
Both a double-stranded RNA-dependent protein kinase (PKR)-phosphorylation homology domain (PePHD) within the E2 protein and a PKR-binding domain within the nonstructural 5A (NS5A) protein of hepatitis C virus (HCV) genotype 1 isolates inhibit the function of the interferon alfa (IFN-alpha)-induced antiviral effector protein PKR in vitro. We investigated whether the mutational pattern of the E2 region (codons 618-681, including PePHD) of 81 HCV genotype 1-infected patients (HCV-1b [n = 54], HCV-1a [n = 27]) influences the response to IFN-alpha. Initial viral decline (DeltaHCV RNA) was determined at week 1 hereby covering the effector reactions of IFN-alpha-mediated first phase and the immune-mediated second phase. DeltaHCV RNA less than 50% (group 1); DeltaHCV RNA greater than 50% but less than 90% (group 2); and DeltaHCV RNA > or =90% (group 3) were differentiated. The PePHD region was highly conserved; the few mutations (5 patients) did not correlate with DeltaHCV RNA or sustained virologic response to IFN-alpha. Within the flanking regions before and after PePHD (codons 618-681) 72 of 81 patients (89%) had 2.6+/-0.17 mutations (median, 3; range, 1-8) that did not correlate with treatment response. Sequence analysis of the NS5A protein (codons 2,209-2,274, including interferon sensitivity determining region [ISDR]) in 39 of 81 patients showed a higher mean number of mutations in the ISDR (codons 2,209-2,248) in groups 2 (1.28+/- 0.43 [n = 18]) and 3 (1.89+/-0.54 [n = 9]) than in group 1 (0.67+/- 0.19 [n = 12]; P =.049 group 1 vs. 3) and a mutant type ISDR (e.g., > or =4 mutations) was significantly more frequent in sustained virologic responders than in nonresponders or relapsers (2 of 4 [50%] vs. 2 of 35 [6%]; P =.045). Thus, NS5A appears to be functionally relevant in IFN-alpha-induced effector reactions.
Combination therapy with interferon-alpha (IFN alpha) plus Ribavirin has been shown to improve the response rate in patients with chronic hepatitis C as compared to IFN alpha alone. However, the mode of anti-viral action of Ribavirin is still unknown. To prove, whether Ribavirin has any additional effect on the decline of hepatitis C viremia during the first weeks of treatment patients with and without combination therapy were compared. Kinetic studies were performed in patients who either responded to IFN alpha alone or IFN alpha plus Ribavirin combination as well as in nonresponders to both forms of therapeutic approaches. 64 IFN alpha naive patients with histologically proven chronic hepatitis C were included in the study. Patients were randomized to receive either IFN alpha-2a (Hoffmann-La Roche) 6 MU thrice weekly or IFN alpha 6 MU tiw plus Ribavirin (Meduna) 14 mg/kg/day for 12 weeks. 37 patients (58%) became HCV RNA-negative (= responders; 17 [46%] with IFN alpha alone, and 20 [54%] with combination therapy). 27 patients remained HCV RNA-positive (= non-responders; 13 [48%] with IFN alpha alone, and 14 [52%] with combination therapy). HCV RNA concentrations were measured in all patients at baseline as well as 1, 2, 4, and 12 weeks after the start of treatment (bDNA assay, Chiron). Using nonradioactive single-stranded conformation (SSCP)-analysis of the HCV hypervariable region 1 we investigated further whether initial viral decline is correlated with changes in viral quasispecies distribution. In primary responders, ribavirin did not influence hepatitis C viremia decline which was of biphasic nature. Also in nonresponders HCV RNA levels decreased after one week of treatment irrespectively of the mode of therapy (mean 10.0 +/- 2.3 to 5.5 +/- 1.1) (phase 1). In the following weeks, however, 2 types of HCV dynamics could be observed (phase 2). In patients with combination therapy, a further reduction of viremia level could be observed, whereas viremia levels in patients with IFN alpha alone slightly increased (week 12: 3.0 +/- 0.5 MEq/mL [combination, n = 15] vs. 7.5 +/- 2.9 MEq/mL [IFN alpha-mono, n = 12]). The individual response of these nonresponder patients showed, however, marked differences (range percentage decline after 4 weeks, 0-98%). Changes in the viral population (quasispecies distribution) as cause of these differences could be excluded by SSCP-analysis of PCR products of the HCV hypervariable region 1. Ribavirin in combination with IFN alpha exerts an additional anti-viral/immunmodulatory effect which manifests itself in phase 2 of hepatitis C viremia decline. The biphasic decline of hepatitis C viremia also observed in IFN alpha-nonresponders can not be explained by the selection of primary IFN alpha-resistant viral variants. The individual differences in the dynamic of hepatitis C viremia observed in the so called "nonresponders" imply that the term "nonresponder" should be redefined, considering our observation that a marked viral decline can occur in these patients.
BACKGROUND: Before introduction of passive immunoprophylaxis and new antiviral nucleoside analogues the course of hepatitis B recurrence after liver transplantation could hardly be influenced. The result was a inferior graft survival. In the present retrospective analysis of the efficacy of hepatitis B therapy after liver transplantation was analysed retrospectively. PATIENTS AND METHODS: Between 1988 and 1998 in total 179 patients were transplanted due to hepatitis B related liver failure at our centre. All patients received passive immunoprophylaxis with hepatitis B immunoglobulin. In case of reinfection after 1993 an antiviral therapy with famciclovir 1500 mg daily was initiated (n = 26), since 1996 lamivudine (100-150 mg daily) was used (n = 12). In case of viral breakthrough under famciclovir treatment or prophylaxis therapy was switched to lamivudine (n = 22). In case of ineffectiveness of lamivudine an antiviral combination therapy with lamivudine and interferon (n = 4) or lamivudine and famciclovir (n = 4) was initiated. Before availability of antiviral agents or in case of viral breakthrough in total 12 patients were retransplanted due to acute or chronic reinfection. RESULTS: With passive immunoprophylaxis reinfection rate was 33%, 43% and 44% after 1, 3 and 5 years respectively. Without antiviral treatment 52% of patients died within the first year after reinfection. Antiviral therapy with lamivudine or famciclovir improved the one year survival after reinfection to 79%. Suppression of viral replication was more effective with lamivudine. Under lamivudine 26 patients (76%) became HBV-DNA negative, 9 patients HBsAg negative (26%). In contrast no patient became HBsAg negative during famciclovir therapy. Lamivudine was effective also after famciclovir breakthrough in 94% of patients. In case of lamivudine resistant reinfection viral replication could be suppressed with an antiviral combination therapy up to negative HBV-DNA in the hybridization assay. Severe side effects were not observed during any of the antiviral therapies. The graft survival after retransplantation for hepatitis B reinfection was 42% and 25% after one and 3 years. CONCLUSION: Whereas it is generally accepted, that passive immunoprophylaxis lowers the reinfection rate it could be shown in the present study, that antiviral treatment lowers mortality of hepatitis B reinfection. The major problem of lamivudine and famciclovir is viral resistance formation. In this case an antiviral combination therapy might be useful, whereas retransplantation for hepatitis B reinfection should be considered carefully due to inferior graft survival rates.
The release of nickel, chromium and lead from electric kettles to water under conditions simulating regular household use was investigated. Ten out of 26 kettles sold on the Danish market released more than 50 micrograms/l nickel to water, whereas neither lead nor chromium was released in any significant amount. Fifty micrograms/l of nickel in water was chosen as the threshold of action, because concentrations below this value were considered unlikely to provide outbreaks of eczema for those consumers suffering from contact allergy to nickel, who are also sensitive to the content of nickel in the diet. This first part of the study was followed up by a dialogue between the kettle producers and the Danish authorities, leading to a change of construction or design for those kettles that did not comply with the criteria. As a follow-up study another ten kettles were studied to check whether compliance was improved. Two of these ten kettles still released more than 50 micrograms/l nickel to water under the test conditions. These two kettles, however, were subsequently withdrawn from the market. Coffee machines tested similarly did not release aluminium, lead, chromium or nickel in quantities of any significance.
OBJECTIVE: Transjugular intrahepatic portosystemic shunt (TIPS) placement is an established therapy for portal hypertension that leads to variceal bleeding or refractory ascites. We present experiences of the role of TIPS at a liver transplantation center. MATERIAL AND METHODS: One hundred and ten patients were referred to the Radiological Department for TIPS placement. One of the 110 patients had recurrent cirrhosis after liver transplantation with refractory ascites. Function of the TIPS was controlled with Doppler US at 1 day, 1 week, 4 weeks and 4 months after TIPS placement and subsequently every 3 months. Shunt insufficiency was supposed when the blood flow velocity within the stent tract was under 50 cm/s and was an indication for TIPS revision. RESULTS: TIPS was placed in 101 patients. After TIPS placement, 10 patients underwent liver transplantation. While waiting for the new liver, none of them developed variceal rebleeding, ascites or other complications of portal hypertension. Two of the 101 patients had episodes of rebleeding. The frequency of patients undergoing TIPS revision within the first year after TIPS placement was 67.5%, within the second year 38.0% and within the third year 24.4%. The revisions led to sufficient reduction of the portosystemic pressure gradient. CONCLUSION: In some liver transplant candidates, TIPS can be useful in minimizing the risk of complications of portal hypertension during the waiting time for a liver transplantation. TIPS can be monitored by Doppler US and revised if occlusion occurs.