[Postexposure prevention after occupational exposure to HBV, HCV and HIV].
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Acute Disease↗
Biomedical subjects
S Zeuzem
Publications and source records attributed to S Zeuzem.
Downregulation of CD44v6 in colorectal carcinomas is associated with hypermethylation of the CD44 promoter region.
Overexpression of the cell adhesion protein CD44v6 has been demonstrated in colorectal cancer and other gastrointestinal tumors. While CD44v6 is upregulated in benign colorectal adenomas and well-differentiated colorectal cancer tissues, downregulation frequently occurs during disease progression. The mechanism of downregulation, however, is unknown. Therefore, we evaluated the methylation status of the CD44 promoter as a mechanism for decreased CD44v6 expression in advanced colorectal carcinomas. We demonstrated by methylation-sensitive restriction enzyme digestion that the CpG islands of the CD44 promoter were methylated in 6/21 (28%) of benign colorectal adenomas. Interestingly, in colorectal carcinomas the frequency of promoter methylation was significantly increased (10/19; 53%) compared to 7/21 (33%) in the corresponding normal mucosa. Methylation seems to be associated with a more advanced cancer stage, but the trend did not reach statistical significance. In colorectal carcinomas with CD44 promoter methylation CD44v6 mRNA was detected by reverse transcription-polymerase chain reaction in 3/10 carcinomas, whereas in tumors without CD44 promoter methylation CD44v6 expression was observed in 8/9 (P <or= 0.05). These results demonstrated that methylation of the 5'CpG island of the CD44 gene is closely associated with decreased expression of CD44v6 in human colorectal carcinomas.
Adenocarcinoma↗
Randomized, controlled trial with IFN-alpha combined with ribavirin with and without amantadine sulphate in non-responders with chronic hepatitis C.
BACKGROUND/AIMS: Efficacy and safety of interferon-alpha (IFN-alpha)/ribavirin retreatment with or without amantadine sulphate were evaluated in non-responders with chronic hepatitis C. METHODS: Two hundred twenty five consecutive non-responders to previous antiviral treatment(s) with IFN-alpha alone or in combination with ribavirin or amantadine were treated with IFN-alpha 2b 5 MU daily for 4 weeks, 5 MU tiw for 20 weeks, followed by 3 MU tiw for additional 24 weeks combined with ribavirin 1000-1200 mg/d. One hundred fifteen of 225 patients were randomized to receive amantadine sulphate 100 mg bid for 48 weeks. Treatment was discontinued in patients with detectable serum hepatitis C virus (HCV)-RNA at treatment week 24. RESULTS: An overall sustained virologic response with undectable serum HCV-RNA levels was observed in 49/225 patients (22%). Patients infected with HCV-genotype non-1 (P<0.001), low viremia (P=0.011) and only one previous antiviral treatment (P=0.032) were more likely to respond to antiviral retreatment. There was a trend towards higher sustained virologic response rates in patients receiving triple retreatment compared with those treated with IFN-alpha/ribavirin alone (25 versus 18%, P=0.172). CONCLUSIONS: The addition of amantadine was well tolerated and led to an improvement of sustained virologic responses compared with retreatment with IFN-alpha/ribavirin alone, in particular in patients with low baseline viremia.
Adult↗
Hepatitis C viral kinetic models.
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Animals↗
Dynamics of hepatitis C virus quasispecies turnover during interferon-alpha treatment.
Interferon-alpha (IFN) has been shown to accelerate the evolution of hepatitis C virus (HCV) variants (quasispecies) in nonresponder patients. Different sensitivities of HCV variants to IFN are discussed as a possible mechanism. In the present study, quasispecies were investigated in detail by a newly established and validated direct solid-phase sequencing of the hypervariable region 1 (HVR1), during the initial 3 months of IFN therapy. According to single strand conformation polymorphism (SSCP) analysis, 14 of 26 (54%) virologic nonresponders with quasispecies evolution were identified. Six representative patients with SSCP changes were selected for frequent HVR1 sequencing. Pre-existing variants were identified by cloning and sequencing of the pretreatment serum HCV sample. In one patient the major type was substituted by a minor variant within 3 days of treatment while in the majority of patients the pretreatment major type did not decline before days 26-57 of treatment. Total serum HCV RNA levels remained constant in all patients. In conclusion, although quasispecies evolution during IFN therapy is common, it occurs after a wide range of time intervals after initiation of therapy. Thus, nonresponse to IFN cannot exclusively be explained by changes in the quasispecies.
Adult↗
Nodular regenerative hyperplasia of the liver: a rare differential diagnosis of cholestasis with response to ursodeoxycholic acid.
Nodular regenerative hyperplasia of the liver (NRHL) is an uncommon non-malignant finding typically associated with haematological or auto-immune disease. The main clinical symptom is portal hypertension in the absence of underlying liver cirrhosis. The pathogenesis of NRHL remains unknown. We report a case of NRHL with cholestasis and progression to liver insufficiency without any underlying disease and no association with systemic disease or drug intake. Cholestasis and liver function tests improved significantly during treatment with ursodeoxycholic acid (750 mg per day). Based on this case, it may be concluded that treatment with ursodeoxycholic acid might be beneficial in patients with NRHL and progression to liver insufficiency.
Biopsy↗
[Is liver fibrosis a reversible event? Effect of pegylated interferon and ribavirin in patients with chronic hepatitis C].
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Comment↗
Response predictors and results of a long-term treatment with lamivudine in patients with chronic hepatitis B.
INTRODUCTION: European data on outcome and follow-up of long-term lamivudine treatment are sparse. Moreover, little is known about predictors for sustained virologic response and for development of drug resistance in patients with lamivudine monotherapy. Patients and methods : 39 patients (17 HBeAg+, 22 HBeAg-) were treated with lamivudine for a median duration of 2.5 years (range: 0.5-4). Outcome to therapy and predictors for response and drug resistance were analyzed retrospectively. RESULTS: None of the patients lost HBsAg. In 14 of 17 initially HBeAg positive patients the HBeAg status was available at the end of treatment. Loss of HBeAg was observed in 8 patients and 7 of these 8 patients seroconverted to anti-HBe. Five of 6 patients with HBeAg seroconversion and a post-treatment follow-up period showed sustained HBeAg seroconversion. In HBeAg negative patients virologic response (serum HBV DNA< or =1 x 10(5) copies/ml) was observed in 12 of 22 patients after a median treatment period of 2.5 years. Post-treatment follow-up data were available in only 2 patients, one of which remained below 1 x 10(5) HBV DNA copies/ml for one year. Resistance emerged in 15 of 36 patients with available serum HBV DNA data after a median treatment period of 2 years. CONCLUSION: The present retrospective study confirms international data for lamivudine treatment in a central European setting. Lamivudine therapy achieved disease control in more than 50 % of patients treated for chronic hepatitis B. Baseline predictors could neither be identified for sustained virologic response nor for the development of drug resistance.
Adolescent↗
[Chronic hepatitis C virus infection: always treat!--Pro].
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Antiviral Agents↗
[Pegylated interferon plus ribavirin in chronic hepatitis C. More than half of patients show a lasting response].
In the past ten years, treatment of chronic hepatitis C has made great advances. Only five years ago, not more than 16% of the patients experienced a lasting cure; now the HC virus can be eliminated in 54-56%. This has been made possible by an improvement to interferon-alpha by pegylation, that is, retardation, resulting in appreciably longer and more uniform active levels, together with improved eradication by the combination with ribavirin. At the same time, treatment has become more convenient for the patient, since interferon need now be administrated only once weekly, usually on an outpatient basis. In view of the side effects of interferon, treatment must be closely monitored. In the meantime, concrete treatment recommendations are available for every genetic type of HCV, for patients experiencing relapse, and for primary treatment failures.
Antiretroviral Therapy, Highly Active↗
Proton MR spectroscopy of neurometabolites in hepatic encephalopathy during L-ornithine-L-aspartate treatment--results of a pilot study.
Hepatic encephalopathy (HE) is associated with typical changes in neurometabolites most likely being caused by an elevated systemic ammonia level. Blood ammonia is a valid over-all biomarker of HE and thus is regularly determined in clinical trials. The neurometabolites affected in HE can be assessed in vivo by proton magnetic spectroscopy. The aim of this study was to show the effect of the ammonia lowering drug L-ornithine-L-aspartate (OA) on the cerebral glutamate+glutamine/creatine (Glu+GLN/Cr) ratio. In an open clinical trial (pilot study), 15 patients with stable HE were treated with an infusion of 40 g OA over 8 h (5 g/h). Immediately before and 6-8 (mean 6.8) h after start of the infusion, spectroscopy of the parietal white matter was performed and arterial blood ammonia quantified. Glu+GLN/Cr-ratios correlated significantly with ammonia data (Spearman's correlation coefficient rs = 0.72, p < 0.001). Likewise, the OA induced changes (versus baseline before infusion) in blood ammonia level and in Glu+GLN/Cr-ratios correlated significantly rs = 0.54, p = 0.0375). Magnetic resonance (MR) spectroscopy assesses the neurometabolite variation present in HE. OA induced changes in cerebral Glu+GLN/ Cr-ratio were significantly correlated with the drug effects on arterial blood ammonia. These pilot data indicate that MR spectroscopy detects a specific biomarker of HE that may reflect the extent of the cerebral alterations associated with the disease.
Aged↗
TH1/TH2 serum cytokine profiles and soluble TNF-receptor response in patients with chronic hepatitis C during recombinant human interleukin-12 (rHuIL-12) treatment.
Interleukin-12 (IL-12) has many antiviral properties both in vitro and in vivo, such as enhancing cytotoxic lymphocyte reaction, promoting Th1-helper cell response and inducing interferon-gamma - (IFN-gamma) production. The present study investigated possible antiviral effects of recombinant human IL-12 in vivo in 11 chronic hepatitis patients treated with rHuIL-12 subcutaneously in 3 different dosages (0.03, 0.1, 0.5 microg/kg) once weekly for a period of 10 weeks. ELISA was employed to determine before onset of therapy the serum concentrations of IL-12, IL-12p40, IFN-gamma, IL-4, IL-10, tumor mecrosis factor-alpha (TNF-alpha), TNFR p55 and p75, as well as on days 3, 5, 8, 10, 12, 15, 17, 22 after onset of therapy and subsequently weekly until the end of the treatment period and at the end of the 12 months' postobservatory period. The HCV-RNS serum concentration was determined by means of an RT-PCR method. Two to three days after the subcutaneous rHuIL-12 injections there was a transient significant rise of n the serum concentrations of IL-12, IL-12p40, IFN-gamma and TNFR p55, followed by a decrease to the original level. The increases of the IL-12 and IFN-gamma serum concentrations were dose-dependent. In patients where there was a decline of the HCV-RNS concentration in the serum we confirmed a trend to higher IL-12 serum concentrations. The serum levels of IL-2, TNF-alpha and IL-10 fluctuated only during the treatment period. The present study showed that a once-a-week injection of rHuIL-12 results in a merely transient rise of the IL-12, IL-12-p40- and IFN-gamma serum concentrations. This may offer an explanation for the unsatisfactory clinical efficiency of the substance.
Adult↗
Frequency of the Amsterdam criteria in a regional German cohort of patients with colorectal cancer.
Estimates of the colon cancer burden associated with hereditary nonpolyposis colorectal cancer (HNPCC) vary from less than 1 % to more than 5 %. Amsterdam criteria fulfilled within a kindred (classic Amsterdam and Amsterdam II criteria) are widely used to identify patients prone to HNPCC. The present study was initiated to assess the frequency of the Amsterdam criteria within a regional German cohort of 207 patients with a history of colorectal cancer (CRC). Data on individual and family cancer histories were available in 154 patients (73 women, 81 men; mean age at diagnosis 62.4 +/- 13.3 years). A total of 843 first degree relatives have been identified within the kindreds of whom 121 had verified cancers. In 28 of 154 families (18 %), at least one first degree relative of the index patient had CRC. With respect to a typical family history, five kindreds (3.2 %) were likely to suffer from HNPCC on a clinical basis (4 kindreds met the classic Amsterdam criteria and one kindred the Amsterdam II criteria). Testing for microsatellite instability could additionally be performed in 4 of 5 patients who met the Amsterdam criteria and revealed DNA instability in 3 cases. Moreover, a missense mutation of MSH2 (Gly965Asp) was detected in one patient with microsatellite instability. Based on the classic Amsterdam and Amsterdam II criteria approximately 3 % of a regional German cohort of patients with CRC are likely to suffer from HNPCC. However, the final diagnosis of HNPCC can only be established by detection of pathogenic germline mutations within the DNA mismatch repair genes.
Adult↗
Transient mismatch repair gene transfection for functional analysis of genetic hMLH1 and hMSH2 variants.
BACKGROUND: Germline mutations in the mismatch repair (MMR) genes hMLH1 and hMSH2 can cause hereditary non-polyposis colorectal cancer (HNPCC). However, the functional in vitro analysis of hMLH1 and hMSH2 mutations remains difficult. AIMS: To establish an in vitro method for the functional characterisation of hMLH1 and hMSH2 mutations. METHODS: hMLH1 and hMSH2 wild type (wt) genes and several mutated subclones were transiently transfected in mismatch repair deficient cell lines (HCT-116 and LOVO). Apoptosis, proliferation, and regulation of mRNA expression and protein expression of interacting proteins were analysed by Hoechst staining, AlamarBlue staining, real time polymerase chain reaction, and western blotting, respectively. RESULTS: The protein expression of hMLH1 and hMSH2 mutants was significantly decreased after transfection compared with wild type transfections. The hMLH1 and hMSH2 interacting proteins hPMS2 and hMSH6 became detectable only after transfection of the respective wild type genes. In parallel, hMSH6 mRNA levels were increased in hMSH2 wt transfected cells. However, hPMS2 mRNA levels were independent of the mutation status of its interacting partner hMLH1, indicating a post-transcriptional regulating pathway. In the hMLH1 deficient HCT-116 cell line apoptosis was not affected by transfection of any mismatch repair gene, whereas complementation of hMSH2 deficiency in LOVO cells increased apoptosis. Conversely, proliferative activity of HCT-116 was decreased by complementation with hMLH1wt and unaffected in hMSH2 deficient LOVO cells. CONCLUSION: These data show that the cellular role of the MMR genes and its mutations are assessable in a simple transient transfection system and show the influence of MMR gene regulation on major cell growth regulating mechanisms. This method is applicable for the functional definition of mutations in hMLH1 and hMSH2 genes observed in patients with suspected HNPCC.
Adaptor Proteins, Signal Transducing↗
Expression and release of IL-18 binding protein in response to IFN-gamma.
IL-18 and IL-18 binding protein (IL-18BP) are two newly described opponents in the cytokine network. Local concentrations of these two players may determine biological functions of IL-18 in the context of inflammation, infection, and cancer. As IL-18 appears to be involved in the pathogenesis of Crohn's disease and may modulate tumor growth, we investigated the IL-18/IL-18BPa system in the human colon carcinoma/epithelial cell line DLD-1. In this study, we report that IFN-gamma induces expression and release of IL-18BPa from DLD-1 cells. mRNA induction and secretion of IL-18BPa immunoreactivity were associated with an activity that significantly impaired release of IFN-gamma by IL-12/IL-18-stimulated PBMC. Inducibility of IL-18BPa by IFN-gamma was also observed in LoVo, Caco-2, and HCT116 human colon carcinoma cell lines and in the human keratinocyte cell line HaCaT. Induction of IL-18BPa in colon carcinoma/epithelial cell lines was suppressed by coincubation with sodium butyrate. IFN-gamma-mediated IL-18BPa and its suppression by sodium butyrate were confirmed in organ cultures of intestinal colonic biopsy specimens. In contrast, sodium butyrate did not modulate expression of IL-18. The present data suggest that IFN-gamma may limit biological functions of IL-18 at sites of colonic immune activation by inducing IL-18BPa production. Down-regulation of IL-18BPa by sodium butyrate suggests that reinforcement of local IL-18 activity may contribute to actions of this short-chain fatty acid in the colonic microenvironment.
Butyrates↗
Bethesda guidelines: relation to microsatellite instability and MLH1 promoter methylation in patients with colorectal cancer.
BACKGROUND: Microsatellite instability is a hallmark of mismatch repair deficiency in hereditary nonpolyposis colorectal cancer and results from mutations in the mismatch repair genes MLH1 or MSH2 or from gene inactivation associated with DNA methylation. The Bethesda guidelines were established to identify patients with colorectal cancer who should be tested for microsatellite instability. OBJECTIVE: To assess the Bethesda guidelines for detection of microsatellite instability and to determine the role of MLH1 promoter methylation in colorectal cancer. DESIGN: Prospective cohort study. SETTING: Tertiary care referral center in Frankfurt, Germany. PATIENTS: 125 consecutive patients with colorectal cancer. MEASUREMENTS: Patients were assessed according to the Bethesda guidelines, and tumor specimens were analyzed for microsatellite instability. Patients with microsatellite instability were tested for MLH1 promoter methylation and MLH1 and MSH2 germline mutations. RESULTS: Microsatellite instability was detected in 17 of 58 patients who fulfilled and 5 of 67 patients who did not fulfill criteria of the Bethesda guidelines. In 11 of 17 patients with microsatellite instability who fulfilled Bethesda guidelines, an MLH1 (n = 3), MSH2 (n = 7), or combined MLH1 and MSH2 (n = 1) mutation was found. Among the patients with microsatellite instability who did not fulfill Bethesda guidelines, no mutations were observed; MLH1 promoter methylation was observed in 6 of 11 patients with an MLH1 or MSH2 mutation and 5 of 11 patients without an MLH1 or MSH2 mutation. CONCLUSIONS: The Bethesda guidelines are useful for selecting patients for microsatellite instability testing. MLH1 and MSH2 testing should be recommended in all patients with colorectal cancer and microsatellite instability who fulfill at least one Bethesda criterion. MLH1 promoter methylation may accompany rather than initiate carcinogenesis in patients with colorectal cancer who have mismatch repair gene defects.
Adaptor Proteins, Signal Transducing↗
Quasispecies heterogeneity of the carboxy-terminal part of the E2 gene including the PePHD and sensitivity of hepatitis C virus 1b isolates to antiviral therapy.
Two regions within the HCV genome, hypervariable region 1 (HVR1) within the envelope (E)2 region and the PKR-binding domain (PKRbD) comprising the interferon sensitivity determining region (ISDR) within the nonstructural (NS)5A protein, have been reported to correlate with the outcome of antiviral treatment. Recently, a PKR/eIF2alpha phosphorylation homology domain (PePHD) within the E2 protein of HCV-1 isolates was described to inhibit PKR in vitro. PePHD deleted HCV-1 mutants remain capable of binding PKR to some extent while inhibition of PKR was found to be abolished by carboxy-terminal truncated E2 protein. The importance of mutations and quasispecies heterogeneity within the carboxy-terminal part of the E2 protein comprising the PePHD of HCV-1b is unknown. Therefore, the carboxy-terminal part of the HCV E2 gene (codons 618-746) including the PePHD was analyzed by sequencing of PCR products and individual clones of 41 HCV-1b-infected patients with sustained (SR, n = 12), end-of-treatment (ETR, n = 10), or no virological (NR, n = 19) response to antiviral therapy. Two highly conserved regions (codons 658-673 comprising the PePHD and codons 675-704) and one variable region (codons 705-720) were detected within the carboxy-terminal part of E2. No significant correlation of specific mutations or number of mutations with treatment response was observed for the PePHD and the carboxy-terminal part of the E2 protein. Phylogenetic and conformational analyses showed no specific clusters related to treatment outcome. Calculation of genetic complexity and diversity based on nucleotide sequence analyses of 20 individual clones per patient showed no differences between matched SR, ETR, and NR patients. However, calculation of genetic complexity and diversity on the basis of amino acid sequences showed significantly lower normalized Shannon entropy as well as mean Hamming distances for SR patients than in ETR and NR patients (P = 0.029 and P = 0.027, respectively). This indicates that patients achieving a sustained virological response to interferon-alpha-based antiviral therapy may elicit more effective immunological pressure, resulting in continuous clearing of individual variants of HCV quasispecies.
Adult↗
Subcellular distribution and function of Rab3A-D in pancreatic acinar AR42J cells.
Members of the Rab3 subfamily have been linked to the regulation of exocytosis in secretory cells. We have recently shown by Northern blot analysis that pancreatic acinar-like AR42J cells express all four Rab3 isoforms (Rab3A-D). In the present study, we examined the subcellular distribution of endogenously expressed Rab3 proteins and their relation to the amylase-containing secretory compartment in dexamethasone-differentiated AR42J cells. Rab3A and Rab3C were enriched in the cytosol, Rab3B and Rab3D in the membrane fraction. Accordingly, confocal immunocytochemistry revealed that Rab3B and Rab3D were located in a compartment close to the plasma membrane, whereas anti-Rab3A and Rab3C mainly stained the cytosol. Sucrose density gradient centrifugation showed overlapping, but distinct localization of each Rab3 isoform. The order of banding from lighter to more dense fractions was Rab3C < Rab3A < Rab3B < Rab3D. All Rab3 proteins at least partially colocalized with amylase immunoreactivity. Transient overexpression of Rab3 proteins showed that Rab3A inhibited cholecystokinin (CCK)-induced amylase secretion, whereas overexpression of other Rab3 isoforms had no significant effect. In conclusion, our data indicate that the different Rab3 proteins show distinct subcellular distribution, suggesting different impact on exocrine secretory response in dexamethasone-differentiated AR42J cells.
Amylases↗