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Biomedical subjects

J Mössner

Publications and source records attributed to J Mössner.

At least 73 records · Page 4Linked to original sources

Successful clinical application of extracorporal albumin dialysis in a patient with benign recurrent intrahepatic cholestasis (BRIC).

This is a case report of a 36 years old man who has been suffering for 20 years from benign recurrent intrahepatic cholestasis (BRIC). BRIC is a rare autosomal recessive disease characterised by prolonged episodes of intrahepatic cholestasis and pruritus alternating with periods of nearly normal liver function, and does not progress to cirrhosis. Since all former approaches to medical treatment of the patients severe pruritus were ineffective, the patient was treated by 3 sessions of albumin dialysis (MARS, Molecular Adsorbents Recirculating System). MARS dialysis decreased serum bilirubin levels by more than 60 % and effectively lowered serum bile acid levels by 45 %. The course of serum parameters was accompanied by a dramatic clinical improvement of the patients symptoms (pruritus, jaundice, fatigue etc.). MARS therapy appeared to shorten the duration of the cholestatic attack.

Adult↗

[Laparoscopy in differential internal medicine diagnosis].

Diagnostic laparoscopy has still important implications in the differential diagnosis of numerous diseases despite the impact of non invasive imaging procedures. One of the most important indication, besides chronic liver diseases, is staging of malignancies. Laparoscopy improves considerably the predictability whether a distal carcinoma of the esophagus, or a stomach cancer or a pancreatic carcinoma can be resected. Laparoscopy is unbeaten in diagnosing peritoneal metastases. Thus, laparoscopy prevents unnecessary explorative laparotomies. Regarding tumor staging, a comparison is mandatory between minilaparoscopy, conventional laparoscopy in analgosedation performed by the gastroenterologist and laparoscopy in intubation anesthesia performed by the surgeon immediately before planned laparotomy. The significance of minilaparoscopy especially regarding chronic liver diseases and correct diagnosis of liver cirrhosis and hepatocellular carcinoma in cirrhosis will certainly increase. Laparoscopy remains to be an important diagnostic tool in diseases of unknown causes, i.e. fever of unknown origin. Laparoscopic sonography is the most sensitive method to detect small liver tumors, such as metastases or multilocular hepatocellular carcinoma.

Anesthesia, General↗

The tumour suppressor protein p53 can repress transcription of cyclin B.

The tumour suppressor protein p53 has functions in controlling the G(1)/S and G(2)/M transitions. Central regulators for progression from G(2) to mitosis are B-type cyclins complexed with cdc2 kinase. In mammals two cyclin B proteins are found, cyclin B1 and B2. We show that upon treatment of HepG2 cells with 5-fluorouracil or methotrexate, p53 levels increase while concentrations of cyclin B2 mRNA, measured by RT-PCR with the LightCycler system, are reduced. In DLD-1 colorectal adenocarcinoma cells (DLD-1-tet-off-p53) cyclin B1 and B2 mRNA levels drop after expression of wild-type p53 but not after induction of a DNA binding-deficient mutant of p53. Analysis of the cyclin B2 promoter reveals specific repression of this gene by p53. Transfection of wild-type p53 into SaOS-2 cells shuts off transcription from a cyclin B2 promoter-luciferase construct whereas a p53 mutant protein does not. The cyclin B2 promoter does not contain a consensus p53 binding site. Most of the p53-dependent transcriptional responsiveness resides in its 226 bp core promoter. Taken together with earlier observations on p53-dependent transcription of cyclin B1, our results suggest that one way of regulating G(2) arrest may be a reduction in cyclin B levels through p53-dependent transcriptional repression.

Cyclin B↗

A CDE/CHR tandem element regulates cell cycle-dependent repression of cyclin B2 transcription.

Cyclin B is an important regulator of progression through the cell division cycle. The oscillating appearance of cyclin B1 and B2 proteins during the cell cycle is in part due to fluctuating mRNA levels. We had identified earlier a tandem promoter element named cell cycle-dependent element (CDE) and cell cycle genes homology region (CHR) which regulates cell cycle-dependent transcription of cdc25C, cyclin A and cdc2. Here we describe that cyclin B2 transcription is repressed through a novel CDE/CHR element in resting and G(1) cells. By relief of this repression in S and G(2) oscillating expression of cyclin B2 mRNA is achieved during the cell cycle.

Animals↗

[Incidental findings in gastroenterology. Preventing overdiagnosis].

The use of diagnostic imaging procedures and laboratory investigations in gastroenterology can sometimes lead to findings of questionable value. This highlights the problem--also from the point of view of costs--of deciding whether further diagnostic investigation is necessary or not. No requirement for action is given, for example, in the case of shallow diverticula in the esophagus, hiatal hernia in the absence of reflux symptoms, in the case of small cysts or hemangiomas in the liver, polyps on the wall of the gallbladder, hyperplasia of Brunner's glands in the duodenum or fungi in the stools of immunocompetent persons. Of a controversial nature are the recommendations with regard to Helicobacter pylori gastritis, and non-symptomatic gallstones. Further diagnostic clarification is certainly required when such findings as fatty liver, diverticula in the colon or pancreas divisum are encountered.

Diagnostic Imaging↗

Intracellular supply of phospholipids for biliary secretion: evidence for a nonvesicular transport component.

Phospholipids (PL) for biliary secretion could be supplied from the endoplasmic reticulum (ER) to the plasma membrane by cytosolic transfer proteins or transport vesicles. Therefore, we studied whether biliary secretions of PL and apolipoprotein A-I (apo A-I), as markers for the ER-to-Golgi vesicular transport pathway, are tightly coupled in isolated perfused rat livers with enhanced secretion (+60%) of PL after withdrawal of the cholesterol synthesis inhibitor pravastatin (0.1% of chow, fed for 7 days). Blocking agents dissociated the secretion of apo A-I and PL. Brefeldin A as well as cycloheximide inhibited biliary secretion of apo A-I (-52%; -68%), however, not of PL. Both bilirubin ditaurate and taurodehydrocholic acid reduced biliary secretion of PL (-27%; -79%), but not of apo A-I. The data support the concept that PL destined for biliary secretion bypass the vesicular transport pathway of apo A-I through the Golgi compartment, most likely via cytosolic transfer proteins.

Animals↗

Decreased immunogenicity of recombinant hepatitis B vaccine in chronic hepatitis C.

The immunogenicity of hepatitis B vaccine is unknown for patients with chronic hepatitis C, although hepatitis B vaccination is highly recommended in these patients. We therefore studied in a prospective open trial of 59 patients with chronic hepatitis C (mean age 42 years, hepatitis C for >10 years, Child-Pugh score < or = 5) and 58 healthy hospital staff persons the rate of nonresponse (anti-HBs <10 mIU/mL at 9 months) to recombinant hepatitis B vaccine (Gen H-B-Vax(R),10 microg intradeltoidal at month 0, 1, and 6). Nonresponse was observed in 18/59 (31%) patients with chronic hepatitis C and 5/58 (9%) healthy staff persons (P <.005) (vs. 7% in historical controls; P <.005), low response (anti-HBs 10-99 mIU/mL) in 19% of patients with chronic hepatitis C and 17% of staff persons. High-dose booster vaccination led to seroconversion in 12/15 (80%) of primary nonresponders. Primary nonresponse to HB vaccine was related neither to presence of early-stage liver cirrhosis nor magnitude of serum hepatitis C virus (HCV) RNA concentration, nor explained by the presence of human leukocyte antigen (HLA) types (B8 DR3, B44, DR7, DQ2) predisposing to low antibody response to hepatitis B surface antigen. The rate of primary nonresponse to the standard regimen of recombinant hepatitis B vaccine is surprisingly high in patients with longstanding chronic hepatitis C. Therefore, the antibody to HBV surface antigen (anti-HBs) titer response should be determined in these patients. Depending on the response titer, higher booster doses may be required to achieve and maintain seroprotection in these patients.

Adult↗

Photodynamic therapy for advanced bile duct cancer: evidence for improved palliation and extended survival.

Median survival time of nonresectable hilar bile duct cancer is only 4 to 6 months owing to tumor spread in the biliary tree, refractory cholestasis, and sepsis or liver failure. We explored whether local photodynamic therapy of nonresectable bile duct cancer could improve survival. A sample size of 23 patients is required to detect an increase in 6-month survival rate from less than 50% to greater than 70% in a single-arm phase-II trial with a statistical power of 80% (Fleming's single step procedure; alpha = 0.05). Twenty-three consecutive patients (8 women, 15 men; 67 +/- 14 years) with nonresectable bile duct cancer (Bismuth type III n = 2, type IV n = 21) were treated with photodynamic therapy and biliary endoprosthesis. Photofrin (QLT Pharmaceuticals, Vancouver, Canada) (2 mg/kg body weight intravenously) was photoactivated after 1 to 4 days with laser light (630 nm; 242 J/cm(2)) via endoscopic retrograde access. The 6-month survival rate was 91% after diagnosis and 74% after start of photodynamic therapy (30-day mortality rate was 4%) at a median follow-up time of 10.3 months after diagnosis. Causes of death were tumor progression (n = 9) and bacterial infections (n = 4). The median rate of local tumor response was 74%, 54%, 29%, and 67% after the first, second, third, fourth, and fifth photodynamic therapy. Time to progression ranged from 3 to 8 months. All patients, except 1 with diffuse liver metastases, improved in cholestasis, performance, and quality of life. Photodynamic therapy can prevent tumor occlusion of hilar bile ducts. The apparent benefit in survival time should be confirmed in a controlled trial versus palliation by endoprosthesis only.

Adenocarcinoma↗

In rat alveolar macrophages lipopolysaccharides exert divergent effects on the transport of the cationic amino acids L-arginine and L-ornithine.

In rat alveolar macrophages (AMphi) it was tested whether induction of iNOS by lipopolysaccharides (LPS) is accompanied by changes in L-arginine transport and whether L-ornithine, the product of arginase released from AMphi, could, via inhibition of L-arginine uptake, act as a paracrine inhibitor of NO synthesis. Rat AMphi (cultured for 20 h in the absence or presence of 1 microg/ml LPS) were incubated in Krebs-HEPES solution containing [3H]-L-arginine (0.1 microM for 2 min or 100 microM for 5 min) and the cellular radioactivity was determined as a measure of L-arginine uptake. In parallel, cells were incubated for 6 h in Krebs-HEPES solution containing 0-1 mM L-arginine and nitrite accumulation was determined. [3H]-L-arginine uptake (0.1 microM or 100 microM) occurred independently of sodium ions and was inhibited by L-ornithine (EC50: 117 and 562 microM, respectively) and with similar potencies by L-lysine. In LPS-treated AMphi the concentration inhibition curve of L-ornithine was shifted to the right by about a factor of 4, whereas that of L-lysine was only marginally shifted to the right. L-Leucine (0.1 and 1 mM) inhibited [3H]-L-arginine (0.1 microM) by 43 and 58%, respectively, and the effect of 0.1 mM L-leucine was partially sodium dependent. In LPS-treated AMphi, 0.1 mM L-leucine no longer inhibited [3H]-L-arginine and the effect of 1 mM L-leucine was attenuated. Kinetic analysis of the transport of [3H]-L-arginine and [14C]-L-ornithine revealed two components for each amino acid with Km values of 21 and 114 microM (L-arginine) and 39 and 1050 microM (L-ornithine), respectively. After LPS treatment Km2 of L-arginine transport was reduced to 63 microM and Vmax of both components was increased, whereas Km2 of L-ornithine transport was enhanced to 1392 microM and Vmax1 reduced. LPS-stimulated AMphi, incubated in amino acid-free Krebs-HEPES solution, produced about 4 nmol nitrite/10(6) cells per 6 h, and L-arginine enhanced nitrite accumulation maximally about threefold (EC50: 30 microM). L-ornithine, up to 3 mM, failed to affect significantly nitrite accumulation observed in the presence of 30 or 100 microM L-arginine. Rat AMphi express mRNA for two cationic amino acid transporters (CAT-1 and CAT-2B), and LPS markedly up-regulated mRNA for CAT-2B in parallel with mRNA for iNOS, but had no effect on that for CAT-1. In conclusion, in rat AMphi LPS up-regulates L-arginine transport and induces changes in the characteristics of the cationic amino acid transport resulting in preferential transport of L-arginine. These effects may be regarded as cellular measures to ensure a high L-arginine supply for iNOS.

Animals↗

Neoadjuvant photodynamic therapy before curative resection of proximal bile duct carcinoma.

BACKGROUND: Hilar bile duct carcinoma has an 80% probability of local recurrence after curative resection, which might be reduced if neoadjuvant photodynamic therapy is feasible. CASE AND TREATMENT: After intravenous injection of sodium porfimer we treated an adenocarcinoma of the proximal common bile duct (T2 N0 M0, Bismuth type II) in a 72-year-old man with red laser light (applied from the lumen at a dose 250 Joules/cm2), and the adjacent right and left hepatic and common bile duct at a dose of 125 Joules/cm2. After 23 days the tumor was completely resected (adenocarcinoma pT2 pNO; G2). RESULTS: In the lumenal, 4-mm-thick layer the bile duct specimen exhibited complete tumor necrosis with pigmentation of photodegraded porfimer and no viable tumor cells, while in the outer layer of the wall (at 5-8-mm depth) viable cancer cell nests without degraded porfimer were seen. The bile duct tissue showed little damage. Eighteen months after surgery, neither tumor recurrence nor stricture formation was found at the pretreated bilioenteric anastomoses. CONCLUSIONS: a) Photodynamic therapy with sodium porfimer seems to be confined to the superficial 4-mm layer of bile duct cancer. b) Neoadjuvant photodynamic therapy is feasible for hilar bile duct carcinoma.

Adenocarcinoma↗

A phase II study of pegylated liposomal doxorubicin for treatment of advanced hepatocellular carcinoma.

BACKGROUND: Pegylated liposomal doxorubicin has an enhanced efficacy and reduced toxicity compared with free doxorubicin. The efficacy and toxicity of pegylated liposomal doxorubicin was investigated in patients with hepatocellular carcinoma. PATIENTS AND METHODS: Patients with histologically confirmed, locally advanced or metastatic hepatocellular carcinoma and a Karnofsky index > 60% were included in this prospective single-arm study. Exclusion criteria were liver cirrhosis stage Child-Pugh C, previous chemotherapy, or chemoembolization. Pegylated liposomal doxorubicin was given in a dose of 30 mg/m2 every three weeks until progression of disease. After inclusion of five patients the dose could be escalated to 40 mg/m2 in absence of toxicity grade 3 and 4. RESULTS: Sixteen patients were evaluable for response. No objective response was achieved. The median survival time was 140 days (95% confidence interval: 126-154 days). Treatment toxicities grade > or = 3 comprised increased liver enzymes in patients with preexisting grade 1 or 2 elevation (n = 6), hematologic toxicity (n = 5), and hypersensitivity (n = 2). CONCLUSIONS: Pegylated liposomal doxorubicin is not effective for treatment of advanced hepatocellular carcinoma. The favorable toxicity profile was confirmed even in patients with underlying liver disease.

Adult↗

Chronic pancreatitis associated with an activation peptide mutation that facilitates trypsin activation.

BACKGROUND & AIMS: Mutations of the cationic trypsinogen have been described in hereditary pancreatitis. We report a new trypsinogen mutation in the activation peptide of the proenzyme in a family with chronic pancreatitis. METHODS: The coding region of the cationic trypsinogen gene was sequenced after polymerase chain reaction amplification. The following peptides homologous to the N-terminal end of cationic trypsinogen were synthesized (one-letter code, mutated amino acid underlined): wild-type peptide, APFDDDDKIVGG; pD22G, APFDDDGKIVGG; pK23R, APFDDDDRIVGG. The sequences of pD22G and pK23R correspond to the recently identified mutation K23R and to the mutation described here (D22G). To mimic trypsinogen activation, these peptides were digested with trypsin for 30 minutes at pH 5.0-8. 0, and the fragments were analyzed by high-performance liquid chromatography. RESULTS: In a family with clinical evidence of hereditary chronic pancreatitis, a missense mutation of codon 22 (GAC-->GGC) of the cationic trypsinogen was found. This mutation results in a substitution of aspartic acid by glycine; therefore, the mutation was called D22G. Chromatographic analysis of tryptic digests of the peptides pD22G and pK23R showed hydrolysis rates of 22% and 75%, respectively, whereas the wild-type peptide was hydrolyzed at only 6%. The cleavage rates were reduced at lower pH, and no hydrolysis occurred without trypsin. CONCLUSIONS: The activation peptides of the trypsinogen variants D22G and K23R could be released at a higher rate than in wild-type trypsinogen, resulting in increased amounts of trypsin in the pancreas, which could initiate pancreatitis.

Adult↗

Decrease of CA 19-9 during chemotherapy with gemcitabine predicts survival time in patients with advanced pancreatic cancer.

Chemotherapy with gemcitabine has been shown to be an effective regimen in advanced or metastatic pancreatic cancer with improvement of both quality of life and survival time. The response of the tumour marker CA 19-9 to chemotherapy with gemcitabine was studied in order to find out whether it is related to survival time of patients. Forty-three consecutive patients (median age 61 years, range 39-76 years; 20 males, 23 females) suffering from histologically proven locally advanced or metastatic pancreatic adenocarcinoma and a baseline Karnofsky-index > or = 60 were treated with gemcitabine in a dose of 1,000 mg/m(-2) weekly x 7 followed by 1 week of rest during the first cycle and thereafter 1,000 mg/m(-2) weekly x 3 followed by 1 week of rest until progression. In 36 of 43 patients serial measurements of CA 19-9 could be performed. Patients with a decrease of > 20% of the baseline CA 19-9 level after 8 weeks of treatment (n = 25) had a significantly better median survival than patients with a rise or a decrease < or = 20% (n = 11) (268 vs 110 days; P < 0.001). The response of CA 19-9 was the strongest independent predictor of survival (P < 0.001) in the multivariate analysis. In conclusion, a decrease of CA 19-9 > 20% during the first weeks of chemotherapy with gemcitabine is associated with a better survival of patients with locally advanced or metastatic pancreatic cancer. Serial measurements of CA 19-9 are useful to decide whether further chemotherapy after the first weeks of treatment is indicated.

Adult↗

Helicobacter pylori infection: a risk factor for upper gastrointestinal bleeding after cardiac surgery?

OBJECTIVE: To determine the prevalence of Helicobacter pylori (H. pylori) in critically ill patients who develop upper gastrointestinal bleeding after cardiac surgery in relation to other risk factors. DESIGN: Prospective, single center, cohort study. SETTING: Surgical intensive care unit in a university hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Over a 1-yr period, all consecutive patients with upper gastrointestinal hemorrhage from the stomach or duodenum were studied for H. pylori infection by serology. Additionally, the need for mechanical ventilation over 48 hrs, the duration cardiopulmonary bypass, and the aortic cross-clamp time were analyzed. For control, 229 patients with no evidence of gastrointestinal hemorrhage after cardiac surgery were studied. All patients received stress ulcer prophylaxis with ranitidine. Operations were performed on 2,956 patients during the study period. The incidence of upper gastrointestinal bleeding was 0.9%. Twenty (77%) of the 26 patients with upper gastrointestinal bleeding and 145 (63%) patients of the control group had serologic evidence for H. pylori infection (odds ratio, 1.9; 95% confidence interval 0.7-5.0; p = .2). Patients who required prolonged mechanical ventilation had a significantly greater risk for upper gastrointestinal bleeding (odds ratio, 22.1; 95% confidence interval 8.6-56.7; p<.001). Patients with upper gastrointestinal bleeding also had a significantly longer duration of cardiopulmonary bypass and aortic cross-clamp time (p<.001) CONCLUSIONS: H. pylori is not associated with upper gastrointestinal bleeding in critically ill patients who receive stress ulcer prophylaxis, whereas patients who require prolonged mechanical ventilation are at high risk. A prophylactic eradication of H. pylori is not justified.

Aged↗

Role of various phospholipases A2 and inhibitors in the pathogenesis and prevention of pancreatic acinar cell necrosis: studies with isolated rat pancreatic acini.

BACKGROUND: Phospholipase A2 (PLA2) may play a central role in the pathogenesis of pancreatic acinar cell necrosis. Several questions, however, are unsolved: Is acinar cell necrosis caused by PLA2 derived from infiltrating leukocytes or from pancreatic PLA2 itself? Does PLA2 cause cellular lysis by the release of lysolecithin from lecithin or by generation of free radicals? The aims of this study were to determine which form of PLA2 is responsible for cellular damage and how to inhibit its action. METHODS: Isolated rat pancreatic acini were prepared by collagenase digestion. Newly synthesized proteins were labeled by 35S-methionine. Acini were incubated in buffer to which various factors, such as porcine pancreatic PLA2 or bee venom PLA2, homogenates of either leukocytes or pancreatic homogenates, all with or without lecithin and with or without potential inhibitors (aprotinin, 4-bromophenacylbromide, BM 16.2115, quinacrine, various analogs of arachidonic acid), or free radicals (hydrogen peroxide, xanthine/ xanthine oxidase) with or without allo-purinol or dismutase/catalase were added. Cellular destruction was measured by the release of radiolabeled proteins. RESULTS: PLA2 alone, free radicals, and granulocytes were not harmful to acini within 30 min of incubation. Free radicals caused significant release of radiolabeled proteins only after 3 h of incubation; this release could be inhibited by scavengers. Incubation of pancreatic acini with PLA2 in combination with lecithin caused rapid release of radiolabeled proteins. Addition of high concentrations of enterokinase activated pancreatic homogenates both alone and with lecithin caused release of cellular proteins, suggesting that pancreatic PLA2 uses lecithin from pancreatic membranes as substrate. Almost all tested potential inhibitors of PLA2 were unable to prevent the destruction caused by either pancreatic or bee venom PLA2 and lecithin. However, HK 42, a polyunsaturated fatty acid analog, was able to reduce dose dependently the release of acinar proteins caused by pancreatic PLA2 and lecithin. CONCLUSION: Pancreatic PLA2 and not PLA2 from infiltrating leukocytes may play a role in pancreatic acinar cell necrosis. Cellular lysis is caused upon the action of lysolecithin and probably not via the action of free radicals.

Animals↗