Search PubMed⌕ Search

Biomedical subjects

F Fiedler

Publications and source records attributed to F Fiedler.

At least 19 recordsLinked to original sources
PubMed2001

A novel serotype-specific gene cassette (gltA-gltB) is required for expression of teichoic acid-associated surface antigens in Listeria monocytogenes of serotype 4b.

Listeria monocytogenes serotype 4b strains account for about 40% of sporadic cases and many epidemics of listeriosis. Mutations in a chromosomal locus resulted in loss of reactivity with all three monoclonal antibodies (MAbs) which were specific to serotype 4b and the closely related serotypes 4d and 4e. Here we show that this locus contains a serotype 4b-4d-4e-specific gene cassette (3,071 bp) which consists of two genes, gltA and gltB, and is flanked by palindromic sequences (51 and 44 nucleotides). Complete loss of reactivity with the three serotype-specific MAbs resulted from insertional inactivation of either gltA or gltB. The gltA and gltB mutants were characterized by loss and severe reduction, respectively, of glucose in the teichoic acid, whereas galactose, the other serotype-specific sugar substituent in the teichoic acid, was not affected. Within L. monocytogenes, only strains of serotypes 4b, 4d, and 4e harbored the gltA-gltB cassette, whereas coding sequences on either side of the cassette were conserved among all serotypes. Comparative genomic analysis of a serotype 1/2b strain showed that the 3,071-bp gltA-gltB cassette was replaced by a much shorter (528-bp) and unrelated region, flanked by inverted repeats similar to their counterparts in serotype 4b. These findings indicate that in the evolution of different serotypes of L. monocytogenes, this site in the genome has become occupied by serotype-specific sequences which, in the case of serotype 4b, are essential for expression of serotype-specific surface antigens and presence of glucose substituents in the teichoic acids in the cell wall.

Amino Acid Sequence↗
PubMed2000

Expression profiling in pancreas during the acute phase of pancreatitis using cDNA microarrays.

Most attacks of acute pancreatitis are self-limiting, suggesting that the pancreatic cells adapt their phenotype to prevent progression of the disease. Such phenotypic change must involve a coordinated modification in the expression of numerous genes. To identify differentially expressed genes, high-density mouse cDNA microarrays were hybridized with cDNA probes from both healthy pancreas and pancreas affected by acute pancreatitis. From the 7981 mouse genes analyzed, 239 showed significant changes in their expression during the acute phase of pancreatitis. Among them, 107 genes were up-regulated whereas 132 were down-regulated. They include genes whose function was not previously related to pancreatitis, suggesting that they are involved in some way into the acute pancreatic response. Finally, 40% of differentially expressed genes corresponded to ESTs. Demonstration that a large quantity of unexpected or yet uncharacterized genes showed altered expression during acute pancreatitis underscores the interest of a genome-based investigation. Some of these genes are certainly involved in the cellular defense against pancreatitis and, as such, deserve being studied further.

Acute-Phase Reaction↗
PubMed2000

Esophageal motility disorders in critically ill patients: a 24-hour manometric study.

OBJECTIVE: Impaired tubular esophageal motility is involved in the pathogenesis of gastroesophageal reflux disease, which, in turn, has been shown to cause nosocomial pneumonia in critically ill patients. As multiple factors are involved, this pilot study was undertaken to evaluate whether, similarly, impaired esophageal motility may contribute to nosocomial infections by determining esophageal motility in critically ill patients undergoing mechanical ventilation and sedation in comparison to that of a healthy control group. DESIGN: Open, single-centered study. PATIENTS AND METHODS: Fifteen consecutive ventilated intensive care unit (ICU) patients with different diseases and three regimens of analgo-sedation were included: group 1: no analgo-sedation, group 2: ketamine and benzodiazepines, and group 3: fentanyl and benzodiazepines. Six healthy volunteers were studied as controls. Twenty-four hour esophageal anterograde (propulsive) and retrograde motility changes were assessed by a manometry system. RESULTS: The frequencies of contractions were 0.67 +/- 0.1/min (no analgo-sedation) 0.093 +/- 0.02 (ketamine) and 0.076 +/- 0.01 (fentanyl) (p < 0.05 as compared to controls). The amplitudes (% of maximum) were 98 % (control), 58 % (analgo-sedation), 38 % (ketamine) and 42 % (fentanyl; p < 0.05 for the comparison of fentanyl and ketamine with controls). Whereas the percentage of propulsive contractions was significantly decreased in patients (no sedation: 45 %, ketamine: 34 %; fentanyl: 35 %, p < 0.05) as compared to controls (72 %), the percentage of retrograde contractions increased: no sedation: 29 %, ketamine: 34 % and fentanyl: 37 % as compared to controls: 10 %, p < 0.05. Analysis according to the underlying diseases showed marked inhibition of motility parameters within any disease group in comparison with controls. CONCLUSIONS: Irrespective of the underlying disease, propulsive motility of the esophageal body is significantly reduced during any kind of sedation in critically ill patients. Possibly central as well peripheral drug-related effects are involved in such a depression. Twenty-four hour motility recordings appear to be a valuable and feasible method to quantify and analyze esophageal motor disorders in critically ill patients.

Adult↗
PubMed2000

P45, an extracellular 45 kDa protein of Listeria monocytogenes with similarity to protein p60 and exhibiting peptidoglycan lytic activity.

A monoclonal antibody obtained by immunization of mice with heat-killed cells of Listeria monocytogenes serotype 4d showed reactivity towards a protein (P45) from L. monocytogenes with an apparent molecular mass of 45 kDa. This protein was detected in the culture supernatant and at the cell surface of L. monocytogenes. Proteins cross-reacting with the monoclonal antibody were present in all Listeria strains investigated, except L. grayi. The structural gene was cloned in Escherichia coli and sequenced. Translation of the gene starts at a TTG initiation codon. The gene was found to code for a protein of 402 amino acid residues with a predicted molecular mass of 42.7 kDa. It has a signal peptide of 27 amino acid residues, resulting in a molecular mass for the mature polypeptide of 39.9 kDa. Protein database searches showed that this protein has 55% similarity and 38% identity to protein p60 of L. monocytogenes and exhibits significant sequence similarities to p54 from Enterococcus faecium and Usp45 from Lactococcus lactis. P45 was shown to have peptidoglycan lytic activity and the encoding gene was named spl (secreted protein with lytic property).

Amino Acid Sequence↗
PubMed2000

ASHAP--an effective salvage therapy for recurrent and refractory malignant lymphomas.

BACKGROUND: This study was performed to examine the efficacy and toxicity of the combination of adriamycin (ADR), methylprednisolone (solumedrol), cytarabine (Ara-C), and cisplatin (CDDP) in patients with recurrent and refractory malignant lymphomas. PATIENTS AND METHODS: Sixty-five patients with Hodgkin's disease (HD) (n=14) or non-Hodgkin's lymphomas (NHL) (n = 51) were enrolled in the study. The ASHAP therapy consisted of ADR (40 mg/m2 by continuous infusion (CI) over 96 h), methylprednisolone (500 mg i.v., days 1-5), Ara-C (2 g/m2 as a 2-h infusion on day 5), and CDDP (100 mg/m2 by CI over 96 h). RESULTS: Twenty-five patients (38%) achieved complete remission (CR) and 20 (31%) were taken into partial remission (PR) for an overall response rate of 69%. Thirty-two patients with CR or PR following ASHAP underwent high-dose therapy (HDT) with subsequent hematopoietic stem cell transplantation. After a median follow-up of 52 months, 13 patients are in continuous CR (CCR), the 3-year event-free survival (EFS) was 30% for responders and 21% for all patients. The median overall survival (OS) was 12 months (range 0-70 months), and the OS rate after 3 years was 32%. Unfavorable prognostic factors for EFS and OS by univariate analysis were an elevated value of the serum lactate dehydrogenase and refractory lymphoma. The most frequently observed side effects following ASHAP were leukocytopenia and thrombocytopenia of World Health Organization (WHO) grades III/IV in approximately 80% of all courses. Non-hematological toxicities such as gastrointestinal side effects, infections, mucositis, renal and neurotoxicity occurred more rarely and reached WHO grades III/IV only occasionally. No treatment-related mortality with ASHAP was observed. CONCLUSIONS: ASHAP is an effective and moderately toxic salvage therapy for patients with recurrent or refractory HD and NHL. The results in patients responding to ASHAP and afterwards undergoing HDT with stem cell support are comparable with other established protocols and indicate an improvement in survival if HDT is carried out as intensification.

Adolescent↗
PubMed2000

Staphylococcus fleurettii sp. nov., isolated from goat's milk cheeses.

A new coagulase-negative and novobiocin-resistant species of the genus Staphylococcus, Staphylococcus fleurettii, isolated from raw-milk cheeses, is described. This species is differentiated from the other novobiocin-resistant staphylococci on the basis of ribotype and intergenic transcribed spacer patterns, DNA-DNA reassociation reactions, cell wall composition and phenotypic characteristics. S. fleurettii could be distinguished by its oxidase activity, by its ability to produce acid aerobically from D-trehalose, D-mannose, D-turanose and maltose and by its inability to produce acid from D-cellobiose. The type strain of S. fleurettii is CIP 106114T (= DSM 13212T).

Animals↗
PubMed2000

Listeria monocytogenes-infected human dendritic cells: uptake and host cell response.

Dendritic cells (DCs) are potent antigen-presenting cells and play a crucial role in initiation and modulation of specific immune responses. Various pathogens are able to persist inside DCs. However, internalization of the gram-positive bacterium Listeria monocytogenes into human DCs has not yet been shown. In the present study, we demonstrate that human monocyte-derived immature DCs can efficiently phagocytose L. monocytogenes. This uptake is independent of listerial adhesion factors internalin A and internalin B but requires cytoskeletal motion and factors present in human plasma. A major portion of internalized bacteria is found in membrane-bound phagosomes and is rarely free in the cytosol, as shown by transmission electron microscopy and by using an L. monocytogenes strain expressing green fluorescent protein when in the host cell cytosol. The infection caused maturation of the immature DCs into mature DCs displaying high levels of CD83, CD25, major histocompatibility complex class II, and the CD86 costimulator molecule. This effect appeared to be largely mediated by listerial lipoteichoic acid. Although L. monocytogenes infection is known to induce death in other cell types, infection of human DCs was found to induce necrotic but not apoptotic death in fewer than 20% of DCs. Therefore, the ability of DCs to act as effective antigen-presenting cells for listerial immunity is probably enhanced by their resistance to cell death, as well as their ability to rapidly differentiate into mature, immunostimulatory DCs upon encountering bacteria.

Antigens, CD↗
PubMed2000

A sheep in wolf's clothing: Listeria innocua strains with teichoic acid-associated surface antigens and genes characteristic of Listeria monocytogenes serogroup 4.

Listeria monocytogenes serotype 4b has been implicated in numerous food-borne epidemics and in a substantial fraction of sporadic listeriosis. A unique lineage of the nonpathogenic species Listeria innocua was found to express teichoic acid-associated surface antigens that were otherwise expressed only by L. monocytogenes of serotype 4b and the rare serotypes 4d and 4e. These L. innocua strains were also found to harbor sequences homologous to the gene gtcA, which has been shown to be essential for teichoic acid glycosylation in L. monocytogenes serotype 4b. Transposon mutagenesis and genetic studies revealed that the gtcA gene identified in this lineage of L. innocua was functional in serotype 4b-like glycosylation of the teichoic acids of these organisms. The genomic organization of the gtcA region was conserved between this lineage of L. innocua and L. monocytogenes serotype 4b. Our data are in agreement with the hypothesis that, in this lineage of L. innocua, gtcA was acquired by lateral transfer from L. monocytogenes serogroup 4. The high degree of nucleotide sequence conservation in the gtcA sequences suggests that such transfer was relatively recent. Transfer events of this type may alter the surface antigenic properties of L. innocua and may eventually lead to evolution of novel pathogenic lineages through additional acquisition of genes from virulent listeriae.

Amino Acid Sequence↗
PubMed2000

Absence of serotype-specific surface antigen and altered teichoic acid glycosylation among epidemic-associated strains of Listeria monocytogenes.

Outbreaks of food-borne listeriosis have often involved strains of serotype 4b. Examination of multiple isolates from three different outbreaks revealed that ca. 11 to 29% of each epidemic population consisted of strains which were negative with the serotype-specific monoclonal antibody c74.22, lacked galactose from the teichoic acid of the cell wall, and were resistant to the serotype 4b-specific phage 2671.

Antibodies, Monoclonal↗
PubMed2000

Gemcitabine in the treatment of refractory Hodgkin's disease: results of a multicenter phase II study.

PURPOSE: To explore the use of gemcitabine for the treatment of patients with relapsing or refractory Hodgkin's disease. PATIENTS AND METHODS: Eligible patients had measurable disease and more than one previous chemotherapy regimen. Patients previously treated with high-dose chemotherapy with autologous bone marrow or peripheral stem-cell support were not included. Gemcitabine, 1,250 mg/m(2), was administered as a 30-minute intravenous infusion on days 1, 8, and 15 of each 28-day cycle of therapy. The dosing schedule remained fixed, and any dose of gemcitabine that could not be given on time was omitted. Patients who had not experienced any hematologic or nonhematologic toxicity after one complete cycle of therapy were permitted to have subsequent doses increased by 20%: that is, from 1, 250 mg/m(2) to 1,500 mg/m(2). RESULTS: Of the 23 enrolled patients, 22 were assessable for response; all 23 patients were included in the efficacy analysis. Disease status for two patients (9%) reached a state of complete remission, and seven patients (30%) achieved a partial response, for an overall response rate of 39% (95% confidence interval, 19.7% to 61.5%). The likelihood of achieving a response was not influenced by a patients' main pretreatment characteristics or by their response to their last prior chemotherapy. The median duration of response was 6.7 months (range, 2 to 33+ months), and the median overall survival time was 10.7 months (range, 4 to 34.7+ months). In general, toxicities were mild; no treatment-related deaths occurred, and only one life-threatening adverse event was reported for this study. CONCLUSION: Gemcitabine was shown to be active in heavily pretreated patients with Hodgkin's disease, producing a response rate of 39%. Additionally, drug-related toxicities were mild, which thus suggests the possible inclusion of gemcitabine in an earlier phase of treatment.

Adult↗
PubMed2000

Telemedicine: application of telepathology-remote microscopy for intraoperative diagnoses on frozen sections.

Due to the time delay, intraoperative consultations result in an extension of operation times, leading to prolonged anesthesia and idle time during surgery. Using a remote controlled microscope for telepathology, transfer times between hospital and pathologist can be eliminated and pathological expertise obtained independently of the geographic location of the hospital. In cooperation with a community hospital located 100 km apart from the Institute of Pathology of the Justus Liebig University Giessen, telepathological intraoperative consultations have been performed since 1999. After preparation and staining of the cryosection in the hospital, the slide was examined in our institute using a remote-controlled microscope (Leica DMRXA) and a special telepathological software (Leica TPS1). Data were transferred via two ISDN connections in parallel. The telepathology system contains an additional macroscopic examination equipment. Up to now more than 40 telepathological consultations have been done. Time required for the microscopic diagnosis ranged between 4 and 25 minutes. The amount of time saved, compared to the transfer to the next available pathologist, was approximately 45 minutes. In our experience, telepathological diagnoses were fully in accordance with conventional diagnoses routinely performed afterwards. The application of telepathology can lead to a significant shortening of surgery time if a pathologist is locally not available. In the study presented, no diagnostic errors occurred. The additional application of a macroscopic equipment allows inspection and interactive guidance for sampling, thus preventing sampling errors.

Efficiency↗
PubMed1999

Structural and functional characterization of the mouse p8 gene: promotion of transcription by the CAAT-enhancer binding protein alpha (C/EBPalpha) and C/EBPbeta trans-acting factors involves a C/EBP cis-acting element and other regions of the promoter.

Rat p8 mRNA was discovered because of its strong activation in pancreas during the acute phase of pancreatitis. We report here structural and functional data on the mouse p8 gene. The mouse p8 polypeptide is 80 amino acids long and shows 91% and 75% identity with its rat and human counterparts respectively. The p8 gene is organized into three exons interrupted by two introns. Promoter regions involved in the regulation of p8 gene expression in NIH 3T3 cells were analysed. Chloramphenicol acetyltransferase (CAT) reporter assays with progressive deletions of the 5' flanking region of the mouse p8 gene revealed four silencer elements located from nucleotides -5000 to -1472, -1471 to -671, -670 to -473, and -239 to -117 respectively. One positive element was identified between nucleotides -117 and -72. We identified a CAAT-enhancer binding protein (C/EBP) cis-acting element at position -111. Site-directed mutagenesis of this consensus site decreased promoter activity to 5% of that of the wild-type. An electrophoretic mobility-shift assay, using an oligonucleotide probe corresponding to the C/EBP consensus and nuclear extracts of NIH 3T3 cells transfected with C/EBPalpha or C/EBPbeta expression vectors, generated specific DNA-protein complexes that were supershifted with specific antibodies against C/EBPalpha and C/EBPbeta. Co-transfection with C/EBPalpha or C/EBPbeta expression vectors and the p-116/+36p8-CAT construct increased the reporter gene activity in a dose-dependent fashion. Surprisingly, overexpression of C/EBPalpha or C/EBPbeta still increased the promoter activity of both pC/EBPmut-116/+36p8-CAT (which contains the C/EBP mutated site) and the p-71/+36-CAT construct (which does not contain the C/EBP site). Collectively, these results show that C/EBPalpha and C/EBPbeta trans-acting factors can promote transcription of the mouse p8 gene (i) by direct binding to the C/EBP consensus site, and (ii) by enhancing the activity of other trans-acting factors interacting with the p8 promoter.

3T3 Cells↗
PubMed1999

Listeria monocytogenes infection of Caco-2 human epithelial cells induces activation of transcription factor NF-kappa B/Rel-like DNA binding activities.

The effect of Listeria monocytogenes infection on the cellular level of transcription factor NF-kappa B in the human epithelia-like cell line Caco-2 was investigated. Infection with L. monocytogenes or treatment with lipoteichoic acid induced the formation of three NF-kappa B-like DNA-protein complexes C1, C2, and C3, which were identified as containing either, RelA and p50, RelB and p50, or p50, respectively. NF-kappa B activation in L. monocytogenes-infected Caco-2 cells was distinct from NF-kappa B activation in infected P388D1 macrophages concerning the NF-kappa B complexes formed and the kinetics of the induction.

Caco-2 Cells↗
PubMed1999

Lipopolysaccharides induce p8 mRNA expression in vivo and in vitro.

Systemic LPS endotoxin is associated with acute pancreatic damage. Whether damage results from direct interaction of LPS with pancreatic cells is unknown. We addressed that question by monitoring p8 expression in reponse to LPS, in vivo and in vitro, because overexpression of the p8 protein is a sensitive marker of pancreatic agression. For in vivo studies, rats were sacrificed at different times after a single intraperitoneal injection of LPS, and pancreas, liver, kidney, lung, brain, and intestine were processed for RNA preparation. In vitro, pancreatic acinar AR4-2J cells were cultivated with 0.1, 1, or 10 micrograms/ml LPS for 6, 12, or 24 h. p8 mRNA expression was monitored by Northern blotting. In vivo, it was strongly increased in the pancreas after 12 h of treatment and remained elevated after 24 h. It was also induced in kidney and liver, with a maximum at 6 and 12 h, respectively, but not in lung, brain, or intestine. In AR4-2J cells, basal p8 mRNA expression was very low and increased in a time- and dose-dependent manner after treatment with LPS. LPS-induced overexpression of p8 mRNA in vivo confirmed the adverse effect of endotoxemia on pancreas and its overexpression in vitro demonstrated a direct interaction of LPS with pancreatic cells.

Animals↗
PubMed1999

Interaction between the protein InlB of Listeria monocytogenes and lipoteichoic acid: a novel mechanism of protein association at the surface of gram-positive bacteria.

InlB is a Listeria monocytogenes protein that is sufficient to promote entry in a variety of mammalian cells. The last 232-amino-acid domain (Csa) of InlB has been shown to mediate attachment on the listerial surface, although its sequence does not suggest any known mechanism of association to the bacterial surface. InlB is present both on the bacterial surface and in culture supernatants. As has been recently demonstrated, both forms of InlB, soluble and surface-bound, can trigger signalling in host cells. To elucidate the specific role of each of the two forms, it was important to understand how InlB associates with the bacterial surface. Using microscopy, we find evidence that InlB is partially buried in the cell wall layer, and using fractionation experiments we demonstrate that InlB associates with the bacterial cytoplasmic membrane. Moreover, using purified lipoteichoic acid (LTA) and the three polypeptides InlB, Csa, or InlBDeltaCsa (InlB lacking the last 232 amino acids), we demonstrate that LTA is a ligand for the Csa domain of InlB. These results provide the first evidence of an interaction between lipoteichoic acids and a bacterial protein involved in adhesion and signalling, and highlight a new mechanism of protein association on the surface of Gram-positive bacteria.

Bacterial Proteins↗
PubMed1999

Cloning and expression of the human p8, a nuclear protein with mitogenic activity.

We have previously identified a new rat mRNA, provisionally named p8, which showed a strong, but transient, induction in the pancreas in response to acute pancreatitis. We report here the cloning and sequencing of the human p8 cDNA. The human p8 polypeptide is 82 amino acids long and shows an overall identity of 74% with the rat counterpart. The complete structure of the p8 gene was also established. The p8 gene comprises three exons separated by two introns and the gene was mapped to chromosome 16. Analysis of the p8 primary structure suggested the presence of a bipartite motif of nuclear targeting, indicating that p8 may function within the nucleus. This presumption has been confirmed by transfection of COS-7 cells with the p8 cDNA followed by immunostaining with specific antibodies. p8 mRNA expression is induced in some, but not all, cells by serum starvation and ceramide. To analyze the p8 function, we stably transfected HeLa cells with a p8 expression plasmid, and measured their growth and their sensitivity to apoptosis. Response to TNF alpha and staurosporine-induced apoptosis was not modified by p8 expression. However, cells expressing p8 grew significantly more rapidly.

Amino Acid Sequence↗
PubMed1999

Pancreatitis-associated protein protects the lung from leukocyte-induced injury.

BACKGROUND: Severe pancreatitis is often complicated by shock and acute lung failure. Little is known about the pathophysiologic impact of the 16.6-kD lectine, named pancreatitis-associated protein (PAP), which is expressed during pancreatitis and which reduces mortality in a rat model with severe pancreatitis. Therefore, the aim of this study was to investigate the effects of PAP on the pulmonary vasculature after leukocyte activation with N-formyl-Met-Leu-Phe (fMLP). METHODS: The experiments were performed in buffer-perfused isolated rabbit lungs. Mean pulmonary artery pressure, weight gain, and thromboxane A2 synthesis of the lungs were monitored. PAP was obtained by affinity chromatography of pancreas juice from pancreatitic rats. The authors tested whether treatment with PAP (260 microg/l, n = 9; or 500 microg/l, n = 6) before fMLP injection (10(-6) M) influences mean pulmonary artery pressure and edema formation. Lungs that were treated only with fMLP (n = 6) served as controls. Additional experiments in which PAP was applied were performed to study whether PAP (260 microg/l, n = 3; 500 microg/l, n = 3; 1,000 microg/l, n = 3) itself effects lung vasculature. RESULTS: Application of fMLP resulted in an increase of mean pulmonary artery pressure (+/- SD) from 8 +/- 2 mmHg up to 26 +/-13 mmHg (P < 0.01) at a flow of 150 ml/min. Pretreatment with PAP reduced the peak pressure developed after fMLP to 15 +/- 7 mmHg (PAP 260 microg/l; P < 0.05) and to 9 +/- 4 mmHg (PAP 500 microg/l), respectively. In addition, the fMLP-induced lung weight gain of 9 +/- 7 g in the controls was prevented by pretreatment with PAP after 150 min in either concentration. In parallel to the attenuated pressure increase, thromboxane A2 release was significantly suppressed in the 260-microg/l (200 +/- 220 pmol x ml(-1) x min(-1); P < 0.01) and 500-microg/l (285 +/- 70 pmol x m(-1) x min(-1); P < 0.05) PAP groups compared with controls (1,138 +/- 800 pmol x ml(-1) x mi(-1)). Treatment with PAP alone in either concentration did not induce any changes in mean pulmonary artery pressure, weight gain, or thromboxane A2 release. CONCLUSION: Clinically relevant concentrations of PAP prevented fMLP-induced vasoconstriction and edema formation in the lung. These findings point toward a protective effect of PAP on polymorphonuclear neutrophil leukocyte-mediated lung injury.

Acute-Phase Proteins↗