Reactive oxygen species analysis in gastritis patients and p53 methylation analysis in gastric tumor cell line AGS infected by Helicobacter pylori.
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CpG Islands↗
Biomedical subjects
W Stremmel
Publications and source records attributed to W Stremmel.
[Veno-occlusive liver disease after total infradiaphragmatic lymphoid irradiation. A rare complication].
BACKGROUND: Radiotherapy is potentially curative in early stages of follicle center lymphoma. Frequent side effects are pancytopenia, nausea and abdominal discomfort. A radiation-induced liver injury with serious clinical symptoms and changes in liver function is a rare complication. CASE REPORT: Whole abdomen was irradiated in a 49-year-old patient with a centrocytic-centroblastic lymphoma, stage IA (localization: left inguinal region). A total dose of 30 Gy was delivered in a weekly fractionation of five times 1.5 Gy. Kidneys were protected by shielding after a dose of 13.5 Gy, liver blocks were positioned after 25 Gy. During the last 2 days of therapy the patient presented with weight gain, ascites, dyspnoea and elevated liver enzymes. Diagnostics revealed hepatosplenomegaly, ascites and an increased portosystemic pressure gradient. Liver biopsy specimen showed a veno-occlusive disease. Complete relief of symptomatology was achieved within 7 days following placement of a transjugular intrahepatic portosystemic stent-shunt (TIPSS), heparinization and diuretics. Liver enzymes are in the normal range. CONCLUSION: Veno-occlusive disease of the liver (VOD) is a very rare side effect of primary abdominal irradiation of follicle center lymphoma. This complication should be taken into consideration if a patient presents with upper right quadrant pain, ascites and elevation of liver enzymes especially within 4 months following radiotherapy. Genesis of veno-occlusive disease, diagnostics, therapy and a review of the literature are presented.
Angiography↗
[Chronic hepatitis--new therapeutic options].
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Antiviral Agents↗
[Therapy of alcoholic and non-alcoholic fatty liver].
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Anti-Infective Agents↗
A new concept of cellular uptake and intracellular trafficking of long-chain fatty acids.
Fatty acids are the main structural and energy sources of the human body. Within the organism, they are presented to cells as fatty acid:albumin complexes. Dissociation from albumin represents the first step of the cellular uptake process, involving membrane proteins with high affinity for fatty acids, e.g., fatty acid translocase (FAT/CD 36) or the membrane fatty acid-binding protein (FABPpm). According to the thus created transmembrane concentration gradient, uncharged fatty acids can flip-flop from the outer leaflet across the phospholipid bilayer. At the cytosolic surface of the plasma membrane, fatty acids can associate with the cytosolic FABP (FABP(c)) or with caveolin-1. Caveolins are constituents of caveolae, which are proposed to serve as lipid delivery vehicles for subcellular organelles. It is not known whether protein (FABP(c))- and lipid (caveolae)-mediated intracellular trafficking of fatty acids operates in conjunction or in parallel. Channeling fatty acids to the different metabolic pathways requires activation to acyl-CoA. For this process, the family of fatty acid transport proteins (FATP 1-5/6) might be relevant because they have been shown to possess acyl-CoA synthetase activity. Their variable N-terminal signaling sequences suggest that they might be targeted to specific organelles by anchoring in the phospholipid bilayer of the different subcellular membranes. At the highly conserved cytosolic AMP-binding site of FATP, fatty acids are activated to acyl-CoA for subsequent metabolic disposition by specific organelles. Overall, fatty acid uptake represents a continuous flow involving the following: dissociation from albumin by membrane proteins with high affinity for fatty acids; passive flip-flop across the phospholipid bilayer; binding to FABP(C) and caveolin-1 at the cytosolic plasma membrane; and intracellular trafficking via FABP(c) and/or caveolae to sites of metabolic disposition. The uptake process is terminated after activation to acyl-CoA by the members of the FATP family targeted intracellularly to different organelles.
Animals↗
Effective infection, apoptotic cell killing and gene transfer of human hepatoma cells but not primary hepatocytes by parvovirus H1 and derived vectors.
Autonomous parvoviruses preferentially replicate in and kill in vitro-transformed cells and reduce the incidence of spontaneous and implanted tumors in animals. Because of these natural oncotropic and oncolytic properties, parvoviruses deserve to be considered as potential antitumor vectors. Here, we assessed whether parvovirus H1 is able to kill human hepatoma cells by induction of apoptosis but spares primary human liver cells, and whether the former cells can efficiently be transduced by H1 virus-based vectors. Cell death, infectivity, and transgene transduction were investigated in Hep3B, HepG2, and Huh7 cells and in primary human hepatocytes with natural and recombinant H1 virus. All hepatoma cells were susceptible to H1 virus-induced cytolyis. Cell death correlated with H1 virus DNA replication, nonstructural protein expression, and with morphological features of apoptosis. H1 virus-induced apoptosis was more pronounced in p53-deleted Hep3B and p53-mutated Huh7 cells than in HepG2 cells which express wild-type p53. In Hep3B cells, apoptosis was partially inhibited by DEVD-CHO, a caspase-3 inhibitor. In contrast, H1 virus-infected primary hepatocytes were neither positive for nonstructural protein expression nor susceptible to H1 virus-induced killing. Infection with a recombinant parvovirus vector carrying the luciferase gene under control of parvovirus promoter P38 led to higher transgene activities in hepatoma cells than in the hepatocytes. Taken together, H1 virus kills human hepatoma cells at low virus multiplicity but not primary hepatocytes. Thus, recombinant H1 viruses carrying antitumor transgenes may be considered as potential therapeutic options for the treatment of hepatocellular carcinomas.
Apoptosis↗
IL-1beta and IL-10 have dual effects on enteric glial cell proliferation.
Inflammatory bowel disease is typically accompanied by functional and structural changes of the enteric nervous system. In pathological studies, cellular loss and axonal degeneration have been described in the myenteric plexus. However, more recent studies suggest that the proliferation rate of myenteric glial cells is enhanced in animal models of intestinal inflammation. Therefore, we have investigated the effect of different cytokines on the proliferative response of enteric glial cells (EGCs), comparing transformed enteric glial cell lines, primary astrocyte cultures and transformed oligodendrocytes. Cells were incubated in serum-free chemically defined medium in the presence or absence of either interleukin (IL)-1beta or IL-10 at concentrations ranging between 0.1 and 100 ng mL(-1) for 48 h. Subsequently, [3H]thymidine was added to each culture dish for an additional 6 h, and the amount of incorporated [3H] was assessed. IL-1beta significantly and dose-dependently suppressed [3H]-uptake by EGCs. In contrast, IL-10 induced a biphasic response; IL-10 at low concentrations (0.1 ng mL(-1)) caused a significant suppression of [3H]-uptake, whereas high concentrations (5-100 ng mL(-1)) significantly enhanced [3H] uptake. These results indicate that EGC proliferation can be modulated by cytokines. The differential effects of IL-1beta and IL-10 suggest that during intestinal inflammation there may be a regulatory interplay between different classes of cytokines modulating EGC proliferation.
Animals↗
Isolation of enteric glia and establishment of transformed enteroglial cell lines from the myenteric plexus of adult rat.
Although enteroglial cells (EGCs) may play a key role in the inflammatory response of the enteric nervous system, little is known about their immunophysiological properties. To facilitate further characterization of enteric glia, we have developed a novel method to isolate and purify EGCs from the myenteric plexus. Myenteric plexus preparations were enzymatically dissociated and EGCs purified by complement-mediated cytolysis of contaminating cells and transformed by retroviral gene transfer. Primary and transformed cells were characterized immunohistochemically and by dot-blot analysis. Functionally, c-fos mRNA expression was assessed in primary and transformed enteroglial cells. All cells displayed robust glial fibrillary acidic protein, S-100 and vimentin immunoreactivities, but no Thy-1.1, desmin, smooth muscle alpha-actin or C3 complement receptor immunoreactivity. This confirmed their enteroglial lineage and excluded contamination with other cell types. Both primary and transformed EGCs displayed little constitutive c-fos mRNA expression. This, however, could be upregulated by various stimuli, including proinflammatory cytokines. In summary, we present a novel method to purify EGCs from rat myenteric plexus for tissue culture and to establish transformed EGC lines that retain their glial nature and functional properties. Such cell lines are now available for physiological studies of the functional properties of enteric glia in vitro.
Animals↗
Expression and localization of the multidrug resistance proteins MRP2 and MRP3 in human gallbladder epithelia.
BACKGROUND & AIMS: The multidrug resistance protein (MRP) isoforms MRP2 (ABCC2) and MRP3 (ABCC3) play a decisive role in the hepatic secretion of endogenous and xenobiotic conjugates and are differentially expressed in hepatocytes and cholangiocytes. The epithelium of the gallbladder considerably modifies the composition of primary hepatic bile by absorption and secretion; however, the underlying transport mechanisms were largely unknown. Localization of MRP2 and MRP3 may provide an explanation of how the products of phase II conjugation are effluxed from gallbladder epithelia. METHODS: Expression and localization of MRP2 and MRP3 were analyzed by reverse-transcription polymerase chain reaction (RT-PCR) and immunofluorescence microscopy of human gallbladder tissue. RESULTS: Expression of MRP2 and MRP3 was identified in all gallbladders by RT-PCR followed by sequencing of the amplified fragments. Double immunofluorescence microscopy using 2 specific antibodies for the respective MRP isoform showed the simultaneous expression of MRP2 in the apical membrane and MRP3 in the basolateral membrane of gallbladder epithelia. MRP1 protein expression was not detectable. CONCLUSIONS: Our findings show the expression of MRP2 and MRP3 in distinct plasma membrane domains of gallbladder epithelia and provide evidence for the capacity of the gallbladder to secrete xenobiotic and endogenous anionic conjugates into blood via MRP3 and into bile via MRP2.
Aged↗
Combination therapy with interferon-alpha 2b and ribavirin for the treatment of relapse patients and non-responders with chronic HCV infection.
BACKGROUND: Treatment of patients with chronic hepatitis C after failure of an interferon monotherapy remains controversial. While relapse patients have a sustained response after a combination therapy with interferon-alpha 2b 3 x 3 MU/week plus ribavirin 1,000/1,200 mg daily for 24 weeks in up to 49%, the standard therapy for initial non-responders remains to be determined. METHODS: We therefore conducted a large multicenter trial to compare efficacy and safety of a combined interferon/ribavirin therapy in 327 non-responders and 181 relapse patients with chronic HCV infection outside of highly specialized institutions. RESULTS: After 6 months therapy with interferon-alpha-2b 3 MU thrice a week plus ribavirin 1,000/1,200 mg daily for 24 weeks 31% of relapse patients and 11% of initial non-responders achieved a sustained response according to an intent to treat analysis. CONCLUSIONS: These data could not confirm the high rate of sustained responders in relapse patients. In addition we were only able to induce a sustained response in every tenth non-responder. These results might reflect the realistic sustained response rates in a non-biased European population of HCV-infected patients.
Administration, Oral↗
Immunogenicity of two accelerated hepatitis B vaccination protocols in liver transplant candidates.
OBJECTIVE: It is common practice to immunize patients against hepatitis B virus infection prior to orthotopic liver transplantation (OLT). We compared the seroprotection rates of two accelerated schedules with a recombinant hepatitis B vaccine in patients awaiting OLT. DESIGN AND METHODS: Patients were prospectively recruited and vaccinated with either 20 micrograms (group 1, n = 14) or 40 micrograms (group 2, n = 20) hepatitis B surface antigen per dosage. Thirty-nine healthy volunteers served as a historical control group. Patients in all groups were vaccinated with an accelerated schedule (0, 7 and 21 days). All patients underwent clinical and laboratory examinations (HBs antibodies, CD4/CD8 ratio, transaminases). RESULTS: The accelerated hepatitis B vaccination schedules were well tolerated. Eight weeks after the third injection, no significant differences in seroprotection rates were observed between group 1 (31%) and group 2 (26%). There was no correlation with respect to seroconversion rates and gender, smoking habits or CD4/CD8 ratio. CONCLUSION: These data suggest that accelerated vaccination schedules with a recombinant hepatitis B vaccine are safe and well-tolerated, but only achieve poor seroconversion rates in OLT candidates. Increasing the vaccine dose to 40 micrograms hepatitis B surface antigen per injection did not result in a higher response rate. Because of the low risk of acquiring de novo hepatitis B infection after transplantation, it should be questioned whether routine hepatitis B vaccination with standard recombinant vaccines prior to liver transplantation should be recommended any longer.
Adult↗
Vacuolating cytotoxin of Helicobacter pylori induces apoptosis in the human gastric epithelial cell line AGS.
Helicobacter pylori induces cell death by apoptosis. However, the apoptosis-inducing factor is still unknown. The virulence factor vacuolating cytotoxin A (VacA) is a potential candidate, and thus its role in apoptosis induction was investigated in the human gastric epithelial cell line AGS. The supernatant from the vacA wild-type strain P12 was able to induce apoptotic cell death, whereas the supernatant from its isogenic mutant strain P14 could not. That VacA was indeed the apoptosis-inducing factor was demonstrated further by substantial reduction of apoptosis upon treatment of AGS cells with a supernatant specifically depleted of native VacA. Furthermore, a recombinant VacA produced in Escherichia coli was also able to induce apoptosis in AGS cells but failed to induce cellular vacuolation. These findings demonstrate that the vacuolating cytototoxin of H. pylori is a bacterial factor capable of inducing apoptosis in gastric epithelial cells.
Apoptosis↗
Interleukin-6 expression and regulation in rat enteric glial cells.
As yet, little is known about the function of the glia of the enteric nervous system (ENS), particularly in an immune-stimulated environment. This prompted us to study the potential of cultured enteroglial cells for cytokine synthesis and secretion. Jejunal myenteric plexus preparations from adult rats were enzymatically dissociated, and enteroglial cells were purified by complement-mediated cytolysis and grown in tissue culture. Cultured cells were stimulated with recombinant rat interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha, and IL-6 mRNA expression and secretion were assessed using RT-PCR and a bioassay, respectively. Stimulation with TNF-alpha did not affect IL-6 mRNA expression, whereas IL-1beta stimulated IL-6 mRNA and protein synthesis in a time- and concentration-dependent fashion. In contrast, IL-6 significantly and dose-dependently suppressed IL-6 mRNA expression. In summary, we have presented evidence that enteric glial cells are a potential source of IL-6 in the myenteric plexus and that cytokine production by enteric glial cells can be regulated by cytokines. These findings strongly support the contention that enteric glial cells act as immunomodulatory cells in the enteric nervous system.
Animals↗
[Fungi in feces. Disease or myth?].
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Antifungal Agents↗
Functional and histochemical analysis of MDR3 P-glycoprotein in a tetracycline-controlled gene expression system.
Aim of the present study was to establish a cell system to study the physiological function of human MDR3 P-glycoprotein in cellular phosphatidylcholine (PC) secretion. MDR3 cDNA was expressed in HeLa cells using the tet-off system together with a luciferase reporter gene. MDR3 Pgp expression was turned on upon removal of doxycycline as shown by Western blot analysis. Immunohistochemistry using a specific anti human MDR3 Pgp antibody revealed a prominent staining of MDR3 Pgp covering the cytoplasm and the area of the plasma membrane. In presence of doxycycline MDR3 Pgp expression was turned off. For analysis of PC secretory activity, MDR3 Pgp expressing and non-expressing cells as well as control HeLa cells with low endogenous MDR3 were preincubated with [(3)H]choline for synthesis of cellular [(3)H]PC. Cells were then incubated for 2 h in media with 0-4 mM taurocholate (TC) and release of cellular [(3)H]PC was recorded. [(3)H]PC secretion was observed in presence of TC without impairing cell viability. There was a significant increase in [(3)H]PC excretion in MDR3 Pgp expressing cells compared to non-expressing controls (e.g. 4.5 fold at 4 mM TC), revealing a high efficiency of transport activity (turnover). From the data it is concluded that the MDR3 Pgp expressing cell system under control of a doxycycline responsive promotor is functionally active and provides a tool to further study MDR3 Pgp mediated transport.
ATP Binding Cassette Transporter, Subfamily B↗
Fatty acid transporters in plasma membranes of cardiomyocytes in patients with dilated cardiomyopathy.
BACKGROUND: Long-chain fatty acids are one of the major cardiac energy substrates. Although the exact mechanism of myocardial fatty acid uptake is not known, several proteins, including the integral membrane proteins FATP1 (fatty acid transport protein 1) and FAT (fatty acid translocase), are being implicated in this process. The aim of this study was to further investigate FATP1 and FAT in the heart and its potential role in myocardial fatty acid utilization. - METHODS: The expression of FATP1 and FAT in mouse myocardium and in myocardial biopsies of 14 patients with different cardiomyopathies was detected by immunocytochemistry and visualized with a laser scanning microscope. - RESULTS: FAT and FATP1 are co-expressed on the plasma membrane of cardiac endothelial cells and on the sarcolemma of cardiomyocytes. The staining-pattern and the intensity of signal for both transport proteins was constant in different cardiomyopathies compared with the expression in biopsies of patients with other cardiac diseases and the expression in the myocardium of healthy mice. - CONCLUSION: Cardiac endothelial cells and cardiomyocytes express FAT and FATP1 in vivo, suggesting an active part of these proteins in the uptake process of long-chain fatty acids. However, we did not find evidence for an altered expression of fatty acid transport proteins in patients with dilated cardiomyopathy, suggesting that these proteins are of minor importance in this kind of heart failure.
Adult↗
Can monovalent hepatitis A and B vaccines be replaced by a combined hepatitis A/B vaccine during the primary immunization course?
A combined hepatitis A/B vaccine (Twinrix Adult) has been licensed in Germany since 1997. We investigated possible differences in immunogenicity and safety when changing over from vaccinations with monovalent vaccines made by different manufacturers to vaccinations with the combined hepatitis A/B vaccine in an open, randomized, multicenter trial. We therefore compared four different schemes changing over from concomitant vaccinations with monovalent vaccines against hepatitis A and B (Havrix 1440+Engerix-B or Vaqta+Gen H-B-Vax) to combined vaccination against hepatitis A+B with three injections of the combined hepatitis A/B vaccine (0, 1, and 6 month schedule). Local and general symptoms were mostly mild in all five groups. With complete three-dose course using the combined vaccine or an early changeover from monovalent vaccines to the combined vaccine, higher overall anti-HBs seroprotection rates and geometric mean concentrations (GMCs) against hepatitis B could be achieved as early as after 2 months as compared to those groups switching later to the combined vaccine. This study demonstrated for the first time that switching from monovalent hepatitis A and B vaccinations to the combined hepatitis A and B vaccination has no negative influence on the tolerability and improves the immunogenicity.
Adolescent↗
Group B streptococcal beta-hemolysin induces nitric oxide production in murine macrophages.
Group B streptococcus (GBS) is the leading cause of sepsis in neonates. Nitric oxide (NO) release plays a role in the hypotension that characterizes septic shock. To examine the role of the GBS beta-hemolysin in NO production, the murine macrophage line RAW 264. 7 was exposed to a wild-type (WT) GBS isolate and to hyperhemolytic (HH) and nonhemolytic (NH) transposon mutants derived from that isolate. After activation of macrophages by the WT strain, the HH mutant, or cell-free extracts of beta-hemolysin, nitrite release into the supernatant increased >10-fold and inducible NO synthase (iNOS) levels in cell lysates increased up to 10-fold compared with treatment with the NH mutant or extracts from that mutant. Hemolysin-induced NO production was dependent on protein tyrosine kinases and NF-kappaB, but not on extracellular signal-related kinase-1/2-mitogen-activated kinases or protein kinase A. These results indicate that GBS beta-hemolysin induces murine macrophage iNOS via intracellular pathways similar to those that mediate lipopolysaccharide-induced iNOS activation.
Animals↗