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Guido Gerken

Publications and source records attributed to Guido Gerken.

At least 19 recordsLinked to original sources
PubMed2007

Interferon-alpha response in chronic hepatitis B-transfected HepG2.2.15 cells is partially restored by lamivudine treatment.

AIM: To characterize the IFN-response and its modulation by the antiviral compound lamivudine in HBV-transfected HepG2.2.15 cells. METHODS: HepG2.2.15 and HepG2 cells were stimulated with various concentrations of IFN-alpha2a in the presence or absence of lamivudine. Then, total RNA was extracted and analysed by customised cDNA arrays and northern blot for interferon-inducible genes (ISGs). In addition, cellular proteins were extracted for EMSA and western blot. HBV replication was assessed by southern blot or ELISAs for HBsAg and HBeAg. RESULTS: Two genes (MxA, Cig5) with completely abolished and 4 genes (IFITM1, -2, -3, and 6-16) with partially reduced IFN-responses were identified in HepG2.2.15 cells. In 2 genes (IFITM1, 6-16), the response to IFN-alpha could be restored by treatment with lamivudine. This effect could not be explained by a direct modulation of the Jak/Stat signalling pathway since EMSA and western blot experiments revealed no suppression of Stat1 activation and ISGF3 formation after stimulation with IFN-alpha in HepG2.2.15 compared to HepG2 cells. CONCLUSION: These results are consistent with the assumption that chronic hepatitis B may specifically modulate the cellular response to IFN by a selective blockage of some ISGs. Antiviral treatment with lamivudine may partially restore ISG expression by reducing HBV gene expression and replication.

Anti-HIV Agents↗
PubMed2006

Increased frequencies of CD8+ T lymphocytes recognizing wild-type p53-derived epitopes in peripheral blood correlate with presence of epitope loss tumor variants in patients with hepatocellular carcinoma.

Wild-type (WT) sequence p53 peptides are attractive candidates for broadly applicable cancer vaccines. The aim of this study was to evaluate the potential of a WT p53-based immunotherapeutic approach for patients with hepatocellular carcinoma (HCC). Circulating CD8+ T cells specific for WT p53(149-157) and WT p53(264-272) HLA-A*0201 restricted epitopes were directly identified in the peripheral blood by the use of peptide/HLA-A2.1 tetramers in 24 HCC patients. Cytotoxic T lymphocyte (CTL) activity after WT p53 peptide-specific stimulation was assessed by analysis of granzyme B and interferon-gamma mRNA transcription, using a quantitative real-time polymerase chain reaction assay. Tumor immunophenotyping was performed to evaluate the p53 status, the expression of major histocompatibility complex (MHC) and costimulatory molecules in freshly isolated tumor cells. HCC patients exhibited significantly higher frequencies of WT p53-specific memory CD8+ T cells and stronger WT p53-specific CTL activity, when compared with healthy controls. Increased frequencies of p53-specific CD8+ T cells and their activity correlated with selective HLA-A2 allele loss and reduced costimulatory molecule expression of tumor cells. Moreover, augmented numbers of p53-specific T cells coincided with high MHC class II expression in tumor cells but were inversely related to the T status of the tumor node metastasis staging system. Our results indicate the existence of natural immunosurveillance and tumor immune evasion, involving a T cell response against WT p53 tumor antigen in patients with HCC. These findings may have important implications for the future development of cancer vaccines.

Aged↗
PubMed2006

[Recurrent disease after liver transplantation. A therapeutic dilemma or treatable?].

BACKGROUND: Side effects of immunosuppressive drugs, the development of de novo malignancies and disease relapse determine the prognosis of liver transplant patients in the long-term course. RECURRENT DISEASE AFTER LIVER TRANSPLANTATION: Treatment of carefully selected and monitored hepatitis C liver transplant patients with interferon-alpha and ribavirin is safe but less efficacious as compared to the non-transplant setting. Postoperative hepatitis B hyperimmune globulin and nucleoside analog combination therapy has resulted in a decrease of reinfection rates to < 10%. New molecular techniques as well as genotyping of hepatocellular carcinoma gain increasing importance for estimation of recurrence-free survival. Diagnosis of disease relapse in cholestatic and autoimmune liver disease is more challenging than in the non-transplant setting and therapeutic options are limited. Psychiatric evaluation and careful validation of compliance are important issues for estimation of the risk of disease recurrence in patients with alcohol-related liver disease. During long-term course, up to one half of patients die of transplant-related causes; 30-70% of these cases are attributed to relapse of primary disease. CONCLUSION: Further improvement of strategies for prevention and treatment of recurrent disease after liver transplantation is warranted in order to increase long-term survival.

Age Factors↗
PubMed2006

[Angiosarcoma of the liver as a rare cause of rapidly progressive liver failure].

BACKGROUND: Angiosarcoma of the liver is a rare, highly malignant and sometimes diffusely infiltrating vessel tumor with rapid progression and poor prognosis. CASE REPORT: A 46-year-old male patient with rapidly progressive liver failure, initially regarded as decompensation of known alcoholic liver cirrhosis, is reported. The patient was referred to the authors' center for evaluation of liver transplantation, but a massive weight loss despite long absence of any alcohol intake raised the suspicion of a malignant disease. The abdominal ultrasound examination showed a massive hepatomegaly with an extremely inhomogeneous echo structure as well as moderate ascites. A following MRI demonstrated diffuse focal contrast enhancement in the entire liver parenchyma, confirming diffuse infiltration of the organ by a malignant tumor. In addition, MRI was suspicious of bone metastases. The usual tumor markers were normal. Sonographically guided percutaneous liver biopsy established the diagnosis of a malignant vascular tumor with diffuse infiltration of the liver parenchyma. 3 days later the patient died of uncontrollable bleeding from esophageal varices. Macroscopic examination of the liver during autopsy showed multiple lacunae filled with blood. Therefore, the differential diagnosis of a peliosis hepatis was raised. However, histology confirmed the diagnosis of a malignant angiosarcoma with diffuse osseous metastases. CONCLUSION: A diffuse infiltration of the liver by an angiosarcoma in the absence of any definite lesions may lead to a substantial delay of the diagnosis. The only relevant differential diagnosis in this case is the equally rare peliosis hepatis.

Biopsy↗
PubMed2006

Public speaking stress-induced neuroendocrine responses and circulating immune cell redistribution in irritable bowel syndrome.

OBJECTIVES: Augmented neuroendocrine stress responses and altered immune functions may play a role in the manifestation of functional gastrointestinal (GI) disorders. We tested the hypothesis that IBS patients would demonstrate enhanced psychological and endocrine responses, as well as altered stress-induced redistribution of circulating leukocytes and lymphocytes, in response to an acute psychosocial stressor when compared with healthy controls. METHODS: Responses to public speaking stress were analyzed in N = 17 IBS patients without concurrent psychiatric conditions and N = 12 healthy controls. At baseline, immediately following public speaking, and after a recovery period, state anxiety, acute GI symptoms, cardiovascular responses, serum cortisol and plasma adrenocorticotropic hormone (ACTH) were measured, and numbers of circulating leukocytes and lymphocyte subpopulations were analyzed by flow cytometry. RESULTS: Public speaking led to significant cardiovascular activation, a significant increase in ACTH, and a redistribution of circulating leukocytes and lymphocyte subpopulations, including significant increases in natural killer cells and cytotoxic/suppressor T cells. IBS patients demonstrated significantly greater state anxiety both at baseline and following public speaking. However, cardiovascular and endocrine responses, as well as the redistribution of circulating leukocytes and lymphocyte subpopulations after public speaking stress, did not differ for IBS patients compared with controls. CONCLUSIONS: In IBS patients without psychiatric comorbidity, the endocrine response as well as the circulation pattern of leukocyte subpopulations to acute psychosocial stress do not differ from healthy controls in spite of enhanced emotional responses. Future studies should discern the role of psychopathology in psychological and biological stress responses in IBS.

Adrenocorticotropic Hormone↗
PubMed2006

Long-term effectiveness of azathioprine in IBD beyond 4 years: a European multicenter study in 1176 patients.

In Crohn's disease the optimal duration of azathioprine treatment is still controversial and for ulcerative colitis only limited data are available to support its efficacy. Charts of 1176 patients with IBD from 16 European centers were analyzed. Flare incidences and steroid dosages were assessed for the time before and during treatment and after discontinuation. Within the first 4 years, azathioprine suppressed flare incidence and steroid consumption in both diseases (P < 0.001). While in CD discontinuation after 3-4 years did not lead to reactivation, this was the case in UC. However, continuation beyond 4 years further improved clinical activity in CD and steroid requirement in both diseases (P < 0.001). Discontinuation of azathioprine may thus be considered after 3-4 years in CD patients in complete remission without steroid requirement. In all other CD patients and for UC patients in general, continuation seems beneficial. These results support a novel differential algorithm for long-term azathioprine therapy in IBD.

Adult↗
PubMed2006

Biochemical and histological effects of 26 weeks of glycyrrhizin treatment in chronic hepatitis C: a randomized phase II trial.

BACKGROUND/AIMS: Phase I/II studies of 4 weeks duration have confirmed the ALT lowering effect of glycyrrhizin in Western chronic hepatitis C patients. Our aim was to determine the dose frequency of glycyrrhizin required to maintain the ALT response beyond 4 weeks and evaluate its effect on liver histology and quality of life. METHODS: HCV-RNA-positive patients with elevated ALT and marked fibrosis or necro-inflammation who were not eligible for interferon therapy were treated for 4 weeks with six infusions weekly of glycyrrhizin. Patients with an ALT response at week 4 were randomized to continue treatment for 22 weeks in three dose frequency groups: 6x, 3x or once weekly. RESULTS: 72/121 (60%) patients were randomized. At the end of treatment the ALT response was maintained in 60%, 24% and 9% of patients in the 6x, 3x, and once weekly groups, respectively (p<0.001). In ALT responders the necro-inflammation score improved non-significantly compared to ALT non-responders. Quality of life assessed by SF-36 increased in patients treated with the study drug, albeit unrelated to the occurrence of ALT response. CONCLUSIONS: ALT responses induced by 4 weeks glycyrrhizin therapy can be maintained in a subset of chronic hepatitis C patients receiving at least three injections weekly. The observed ALT response did not translate in a significant histological improvement after 6 months treatment.

Adolescent↗
PubMed2006

Trypsin-sensitive modulation of intestinal epithelial MD-2 as mechanism of lipopolysaccharide tolerance.

Intestinal epithelial cells (IEC) are constantly exposed to both high concentrations of the bacterial ligand LPS and the serine protease trypsin. MD-2, which contains multiple trypsin cleavage sites, is an essential accessory glycoprotein required for LPS recognition and signaling through TLR4. The aim of this study was to characterize the expression and subcellular distribution of intestinal epithelial MD-2 and to delineate potential functional interactions with trypsin and then alteration in inflammatory bowel disease (IBD). Although MD-2 protein expression was minimal in primary IEC of normal colonic or ileal mucosa, expression was significantly increased in IEC from patients with active IBD colitis, but not in ileal areas from patients with severe Crohn's disease. Endogenous MD-2 was predominantly retained in the calnexin-calreticulin cycle of the endoplasmic reticulum; only a small fraction was exported to the Golgi. MD-2 expression correlated inversely with trypsin activity. Biochemical evidence and in vitro experiments demonstrated that trypsin exposure resulted in extensive proteolysis of endogenous and soluble MD-2 protein, but not of TLR4 in IEC, and was associated with desensitization of IEC to LPS. In conclusion, the present study suggests that endoplasmic reticulum-associated MD-2 expression in IBD may be altered by ileal protease in inflammation, leading to impaired LPS recognition and hyporesponsiveness through MD-2 proteolysis in IEC, thus implying a physiologic mechanism that helps maintain LPS tolerance in the intestine.

Cell Line↗
PubMed2006

[Specific therapy in acute liver failure].

Acute liver failure is defined as hepatic insufficiency (icterus and coagulopathy), hepatorenal syndrome and encephalopathy, associated with a high mortality. A number of conditions can cause this sudden severe liver failure, which finally triggers a multi-organ response. Its etiology shows considerable geographic variation, with viral hepatitis being the most common cause worldwide, whilst drugs, especially acetaminophen-induced hepatotoxicity, form the most common precipitant in many developed countries. The essential feature of a wide variety of agents is apoptosis and/or necrosis of liver cells which is associated with liver injury and insufficiency. Based on new experimental data, the identification of target molecules involved in apoptosis may offer new therapeutic options and improvement of prognosis scores in patients with acute liver failure.

Animals↗
PubMed2006

Psychological stress and the severity of post-inflammatory visceral hyperalgesia.

OBJECTIVES: Lowered visceral sensory thresholds are a key finding in at least a subgroup of patients with functional bowel disorders. Stress and inflammation contribute to this altered visceral sensory function. We aimed to elucidate the role of repetitive stress and acute mucosal inflammation, alone and in combination, on sensory function. METHODS: In randomized order, trinitrobenzenesulfonic acid (TNBS) plus the equal amount of ethanol or saline were instilled into the colorectum of female Lewis rats. Colorectal distensions (CRD) were performed with a barostat device (3 min/40 mmHg); to quantify the visceromotor response (VMR) to CRD, electromyographic activity (EMG) of the abdominal muscles was recorded. In randomized order, equal numbers of both treatment groups underwent either seven days (1 h/day) repetitive water avoidance stress (WAS) or sham WAS. CRD's were conducted 28 days later. Colonic tissue samples were obtained to characterize inflammation and blood samples were taken at day 28 to measure plasma IL-2 levels by enzyme-linked immunosorbent assay (ELISA). RESULTS: Compared to controls (662+/-114 microV) TNBS (1081+/-227 microV), WAS (1366+/-125 microV) and the combination of both (1477+/-390 microV) significantly augmented the VMR to CRD. TNBS and/or WAS caused significant inflammatory changes at day 5, while only TNBS+WAS also showed signs of mucosal inflammation on day 14 and significantly elevated IL-2 levels on day 28. CONCLUSIONS: Stress and inflammation cause long lasting alterations of visceral sensory function. Concomitant stress further increases post-inflammatory visceral hyperalgesia.

Abdominal Muscles↗
PubMed2006

Cyclosporine versus tacrolimus in patients with HCV infection after liver transplantation: effects on virus replication and recurrent hepatitis.

AIM: To determine the effects of the calcineurin inhibitors, cyclosporine and tacrolimus, on hepatitis C virus (HCV) replication and activity of recurrent hepatitis C in patients post liver transplantation. METHODS: The data of a cohort of 107 patients who received liver transplantation for HCV-associated liver cirrhosis between 1999 and 2003 in our center were retrospectively analyzed. The level of serum HCV-RNA and the activity of recurrent hepatitis were compared between 47 patients who received either cyclosporine or tacrolimus as the primary immunosuppressive agent and an otherwise similar immunosuppressive regimen which did not lead to biliary complications within the first 12 mo after transplantation. RESULTS: HCV-RNA increased within 3 mo after transplantation but the differences between the cyclosporine group and the tacrolimus group were insignificant (P=0.49 at 12 mo). In addition, recurrent hepatitis as determined by serum transaminases and histological grading of portal inflammation and fibrosis showed no significant difference after 12 mo (P=0.34). CONCLUSION: Cyclosporine or tacrolimus as a primary immunosuppressive agent does not influence the induction or severity of recurrent hepatitis in HCV-infected patients after liver transplantation.

Adult↗
PubMed2006

MR colonography for the assessment of colonic anastomoses.

PURPOSE: To assess colonic anastomoses in patients after surgical treatment by means of MR colonography (MRC) in comparison with conventional colonoscopy (CC). MATERIALS AND METHODS: A total of 39 patients who had previously undergone colonic resection and end-to-end-anastomosis were included in the study. MRI was based on a dark-lumen approach. Contrast-enhanced T1-weighted (T1w) three-dimensional (3D) images were collected following the rectal administration of water for colonic distension. The MRC data were evaluated by two radiologists. The criteria employed to evaluate the anastomoses included bowel wall thickening and increased contrast uptake in this region. Furthermore, all other colonic segments were assessed for the presence of pathologies. RESULTS: In 23 and 20 patients the anastomosis was rated to be normal by MRC and CC, respectively. In three patients CC revealed a slight inflammation of the anastomosis that was missed by MRI. A moderate stenosis of the anastomosis without inflammation was detected by MRC in five patients, which was confirmed by CC. In the remaining 11 patients a relevant pathology of the anastomosis was diagnosed by both MRC and CC. Recurrent tumor was diagnosed in two patients with a history of colorectal carcinoma. In the other nine patients inflammation of the anastomosis was seen in seven with Crohn's disease (CD) and two with ulcerative colitis. MRC did not yield any false-positive findings, resulting in an overall sensitivity/specificity for the assessment of the anastomosis of 84%/100%. CONCLUSION: MRC represents a promising alternative to CC for the assessment of colonic anastomoses in patients with previous colonic resection.

Adult↗
PubMed2006

Strengths and weaknesses of dark-lumen MR colonography: clinical relevance of polyps smaller than 5 mm in diameter at the moment of their detection.

PURPOSE: To assess the clinical relevance of dark-lumen MR colonography (MRC) for the detection of colorectal lesions using conventional colonoscopy (CC) and histopathologic examinations as reference standard. MATERIALS AND METHODS: A total of 72 patients underwent MRC and CC. MRC was performed using a contrast-enhanced high spatial resolution T1 weighted 3D volumetric interpolated breathhold examination (VIBE)-sequence. All removed colorectal lesions were evaluated by an experienced pathologist. RESULTS: CC confirmed 65 polyps less than 5 mm in diameter. Non of those lesions could be detected using MRC. Just two (4%) of the 49 removed lesions smaller than 5 mm showed signs of dysplasia. Additionally, CC confirmed 25 polyps between 6-15 mm in diameter (MRC 22). All those 25 lesions were removed in CC. Only four (16%) of those polyps showed signs of dysplasia and malignancy (11, 13, 13 and 15 mm). CONCLUSION: Dark-lumen MRC failed to detect all polyps smaller than 5 mm in diameter which are generally not clinically relevant at the moment of their detection and thus can be kept under surveillance. However, MRC as a non-invasive imaging modality is a promising alternative to CC in the detection of clinically relevant polyps larger than 5 mm in diameter.

Adult↗
PubMed2006

Balloon dilatation vs. balloon dilatation plus bile duct endoprostheses for treatment of anastomotic biliary strictures after liver transplantation.

Biliary strictures after liver transplantation are a therapeutic challenge for endoscopy. Anastomotic strictures occur in 10% of patients after liver transplantation, leading untreated to mortality and ultimately to graft failure. Despite of successful reports, to date, there is no defined endoscopic therapy regimen for these cases. Therefore the aim of this study was to determine the most suitable concept for endoscopic treatment of post-liver transplant anastomotic strictures (PTAS). A total of 72 patients post-liver transplantation, who received endoscopic retrograde cholangiography (ERC) as a consequence of suspected biliary complications were retrospectively screened for the presence of PTAS. In all patients graft rejection or bile duct ischemia were excluded prior to ERC by liver biopsy or Doppler ultrasound respectively. We compared either balloon dilatation (BD) alone or dilatation plus placement of an increasing number of bile duct endoprostheses (BD + endoprostheses) in a retrospective analysis. A total of 25 of 75 patients showed PTAS. Overall, endoscopic therapy was successful in 22 of 25 patients (88%). BD was initially successful in 89% but showed recurrence in 62%. BD + endoprostheses was initially successful in 87%, and recurrence was observed only in 31%. All recurrences were successfully retreated by BD + endoprostheses. During 22 of 109 (20%) treatment sessions stone extraction was necessary. Complication rate was low with bacterial cholangitis in 8 of 109 (7.3%) sessions, mild pancreatitis in 10 of 109 (9%) sessions and minor bleeding in 2 of 25 (8%) sphincterotomies. Median follow-up after conclusion of endoscopic therapy is 6 months (range 1-43). In conclusion, our data confirm that endoscopic therapy of PTAS is highly effective and safe. As primarily successful BD shows a high rate of recurrence, we recommend a combination of BD followed by an increasing number and diameter of endoprostheses. Therapy sessions are effective at short intervals of every 2-3 months.

Adult↗
PubMed2006

Quantitative liver function tests in donors and recipients of living donor liver transplantation.

The unique ability of the liver to regenerate quickly after resection makes living donor liver transplantation (LDLT) possible. This technique uses the unique ability of the liver to regenerate to full size after partial resection. However, the quality and course of this regeneration process in humans are still widely unexplored. In the present study we investigated the quantitative liver function tests galactose elimination capacity (GEC), indocyanine green half-life (ICG), and lidocaine half-life as markers for the quality of the liver regeneration in the first 3 months after LDLT. In this study, 22 consecutive living liver donors and their corresponding recipients were analyzed at baseline and at 10 and 90 days after LDLT. Six recipients lost their grafts during the study period. We compared donors and recipients at the different time points. After LDLT, GEC decreased (-42.6%) and ICG increased (+50.6%) significantly in donors. ICG and GEC remained significantly altered over 3 months in donors with an improvement between days 10 and 90 (GEC, +59.3%; ICG, -9.1%). ICG and GEC improved significantly in recipients between days 10 and 90 (ICG, -63.7%; GEC, +16.3%). The lidocaine half-life showed no significant changes. The donors had better test results and recovered faster than the recipients. In conclusion, after LDLT the parameters for liver capacity and flow remain altered in donors and recipients despite rapid volume growth.

Adult↗
PubMed2006

Living donor liver transplantation for hepatocellular carcinoma: a single-center preliminary report.

Liver transplantation (LT) is the treatment of choice for early hepatocellular carcinoma (HCC) in patients with end-stage liver disease but is limited by the availability of donor organs. Living donor liver transplantation (LDLT) represents an alternative therapeutic option for patients with disease confined to the liver. Between April 1998 and December 2003, 537 patients underwent liver transplantation in our center. Thirty patients with HCC and associated terminal cirrhosis and 4 patients with tumor recurrence after liver resection who underwent LDLT were reviewed. Nineteen patients (55.8%) met the Milan criteria for LT, whereas 15 patients (44.2%) "exceeded" them. The overall survival rates at 1 and 2 years were 68% and 62%, respectively, with a median follow-up of 41 months (range, 17-64 months). Five patients (14.7%) died in the first 30 days after LDLT. Hospital mortality was significantly correlated with age > 60 years. Four patients developed recurrence between 6 and 35 months after LDLT. Recurrence was significantly related to the presence of more than 3 tumor lesions in our series. In conclusion, LDLT is a promising treatment option for patients with HCC. Even longer follow-up and bigger patients' series are needed to fully assess the benefits of LDLT for HCC patients exceeding the Milan criteria.

Adolescent↗
PubMed2006

Liver transplantation for patients with metastatic endocrine tumors: single-center experience with 15 patients.

In contrast to other secondary liver malignancy, orthotopic liver transplantation (OLT) is considered as a treatment modality for nonresectable endocrine liver metastases in selected patients. However, only few series have assessed patient selection criteria and long-term results, and no reports have focused on the impact of new technologies in this regard. Between 1992 and 2004, 28 patients with malignant endocrine tumors underwent evaluation for OLT according to our protocol. Data were entered into a prospective database. During pretransplant evaluation, somatostatin receptor scintigraphy detected extrahepatic metastases not diagnosed in standard imaging in 10 patients. Of them, 3 showed aberrant Ki67 labeling results. One patient was excluded from further evaluation due to severe carcinoid heart. Thus far, 15 patients, 10 men and 5 women, aged 37 to 67 years, were subjected to the transplant procedure (11 deceased donor OLT, 3 living donor liver transplantations, and 1 cluster transplantation). Four patients died during the hospital treatment. The median follow-up of the discharged patients was 60.8 months. The actuarial patient survival was 78.3% at 1 year and 67.2% at 5 years. The actuarial 1-, 2-, and 5-year tumor-free survival amounted to 69.4%, 48.3%, and 48.3%, respectively. Two patients underwent surgery for isolated tumor recurrence. In 2 patients, peptide receptor radiotherapy was carried out because of multilocular recurrent disease. In conclusion, liver transplantation is a realistic therapeutic option for highly selected patients with hepatic metastases of endocrine tumors. Our strategy, which implements strict pretransplant selection and aggressive surgical approach, in case of disease recurrence, in addition to systemic radiopeptide treatment, led to an excellent long-term survival cure, however, is unlikely to be achieved.

Adult↗