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R Fischer

Publications and source records attributed to R Fischer.

At least 73 records · Page 4Linked to original sources
PubMed2001

Molecular characterization of a blue-copper laccase, TILA, of Aspergillus nidulans.

Laccases are blue-copper enzymes, which oxidize phenolic substrates and thereby reduce molecular oxygen. They are widespread within fungi and are involved in lignin degradation or secondary metabolism such as pigment biosynthesis. Many fungi contain several laccases, not all of whose functions are known. In Aspergillus nidulans one, yA, is expressed during asexual development and converts a yellow precursor to the green pigment. We identified a second laccase gene, which encodes a 66.3-kDa protein 37.6% identical to laccase I of A. nidulans. The protein harbors an N-terminal secretion signal, and three characteristic copper-binding centers. The enzyme localizes at the growing hyphal tip. The gene was therefore named tilA (=tip laccase). Deletion or overexpression of the gene had no discernible phenotype under laboratory conditions.

Amino Acid Sequence↗
PubMed2001

Tomato Ve disease resistance genes encode cell surface-like receptors.

In tomato, Ve is implicated in race-specific resistance to infection by Verticillium species causing crop disease. Characterization of the Ve locus involved positional cloning and isolation of two closely linked inverted genes. Expression of individual Ve genes in susceptible potato plants conferred resistance to an aggressive race 1 isolate of Verticillium albo-atrum. The deduced primary structure of Ve1 and Ve2 included a hydrophobic N-terminal signal peptide, leucine-rich repeats containing 28 or 35 potential glycosylation sites, a hydrophobic membrane-spanning domain, and a C-terminal domain with the mammalian E/DXXXLphi or YXXphi endocytosis signals (phi is an amino acid with a hydrophobic side chain). A leucine zipper-like sequence occurs in the hydrophobic N-terminal signal peptide of Ve1 and a Pro-Glu-Ser-Thr (PEST)-like sequence resides in the C-terminal domain of Ve2. These structures suggest that the Ve genes encode a class of cell-surface glycoproteins with receptor-mediated endocytosis-like signals and leucine zipper or PEST sequences.

Amino Acid Sequence↗
PubMed2001

Aspirin (5 mmol/L) inhibits leukocyte attack and triggered reactive cell proliferation in a 3D human coronary in vitro model.

BACKGROUND: Leukocyte attack (LA) and the triggered reactive proliferation of smooth muscle cells (SMCs) are key events for the development of early atherosclerosis and restenosis. In the present study, we used a 3D human coronary in vitro model of LA (3DLA model) to examine the effect of high-dose aspirin on the adhesion and chemotaxis of leukocytes and the reactive proliferative response of SMCs. METHODS AND RESULTS: For dose-finding, the effect of aspirin (1, 2, 5, and 10 mmol/L) on the tumor necrosis factor-alpha-induced upregulation of intercellular adhesion molecule-1 was analyzed in monocultures of human coronary endothelial cells (HCAEC) and the SMCs of the human coronary media (HCMSMC). In cytoflow and Northern blot experiments, the expression of intercellular adhesion molecule-1 was slightly reduced after incubation with 5 mmol/L aspirin, and strong inhibition was found after incubation with 10 mmol/L. In 3DLA models, HCAECs and HCMSMCs were cultured on both sides of a porous filter. For LA, human monocytes or CD4(+) lymphocytes were seeded on the HCAEC side of the 3DLA unit. A dose of 5 mmol/L aspirin inhibited the adherence of monocytes or CD4(+) lymphocytes by 50% (P:<0.01) and the chemotaxis of monocytes by 90% (P:<0.01). The reactive proliferative response of cocultured HCMSMCs after LA, as measured by the uptake of bromodeoxyuridine, was significantly reduced by 83% after selective monocyte attack (P:<0.001) and by 42% after selective CD4(+) lymphocyte attack (P:<0.05). CONCLUSIONS: A local concentration of 5 mmol/L aspirin should be accepted as the lowest rational concentration for the beneficial in vitro effects of high-dose aspirin to be reproduced in clinical studies.

Aspirin↗
PubMed2001

Aspergillus nidulans alpha-1,3 glucanase (mutanase), mutA, is expressed during sexual development and mobilizes mutan.

We established a subtractive cDNA library of Aspergillus nidulans to identify differentially expressed genes during sexual development. One of the clones displayed homology to fungal alpha-1,3 glucanases (mutanase). Since alpha-1,3 glucan is considered the main reserve material accumulated during vegetative growth as a cell wall component and consumed during sexual development, we analyzed this gene in detail. The gene, mutA, is disrupted by three introns and encodes a putative protein of 48 kDa molecular mass with a signal peptide for secretion at the N terminus. The deduced protein displays amino acids 24-42% identical to mutanases of other fungi. A proposed mutan binding domain characterized in, e.g., Penicillium is not present in A. nidulans. Mutanase transcript and GFP reporter analysis in A. nidulans revealed specific induction of the gene during sexual development in Hülle cells. To study the role of mutA during sexual differentiation, we constructed a mutA deletion strain. Although degradation of mutan was affected in this strain, it was still able to form cleistothecia at a number similar to that of wildtype. These results suggest that additional carbon sources are available during sexual development.

Amino Acid Sequence↗
PubMed2001

[Regional and sex-specific differences in fulfillment of patient rights: results of a representative population survey in Munich, Dresden, Vienna and Bern].

OBJECTIVES: The European Office of the World Health Organization formulated the Amsterdam Declaration in 1994, demanding thereby the realisation of the principles of a humane health care. These principles relate to the protection of dignity of personhood, to self-determination, the right of information, and the right of quality, continuity and equality in health care. The present study aims at a gender-specific analysis of the fulfillment of these rights. METHODS: Computer-assisted telephone interviews were conducted during the months February and March 2000 in four German speaking European cities (Munich, Dresden, Vienna and Berne). A paragraph of the Declaration on the Promotion of Patients' Rights was regarded as fulfilled if there was at least 80% agreement. RESULTS: Deficiencies were most pronounced for the provision of community and domiciliary services after hospital treatment and for the right concerning humane terminal care and death in dignity. Moreover, regional differences were found between Munich, Dresden and Vienna on one side and Berne on the other side, with degrees of fulfillment being higher in Berne. CONCLUSIONS: In summary, these regional differences are more pronounced than single gender-specific differences, which may be due to chance. Areas with potential for improvement could be identified and can be actively restructured, e.g., in the context of the setting of health targets. An evaluation of the influence of the managed care system which has been established only sporadically in Berne requires more data.

Adult↗
PubMed2001

[Bone density and 25-OH vitamin D serum level in patients with systemic lupus erythematosus].

OBJECTIVE: To clarify the influence of vitamin D metabolism on bone mineral density (BMD) or bone metabolism in patients with systemic lupus erythematosus (SLE). METHODS: 57 consecutive patients in our department (mean age 33.9 years, 44 female, 13 male) were studied. BMD was measured with dual-X-ray absorptiometry at the lumbar spine and femoral neck. Biochemical investigation of bone metabolism included measurement of vitamin D metabolites, intact parathyroid hormone (PTH), serum osteocalcin und urinary pyridinoline-crosslink excretion. RESULTS: 25 patients had 25-OH cholecalciferol serum values below the normal range after adjustment for seasonal changes; 9 patients were severely vitamin D depleted with 25-OH vitamin D serum values below 5 ng/ml. Low 25-OH-vitamin D was significantly associated with high disease activity. Mean 1.25 (OH)2-vitamin D, PTH, osteocalcin and crosslink excretion were in the normal range. Thirty-six patients had normal BMD; 5 patients had osteoporosis according to WHO diagnosis criteria. No correlation of biochemical parameters of bone metabolism with BMD was found. CONCLUSION: Severe vitamin D depletion was common in this group of patients with SLE even after adjustment for seasonal variations, especially in patients with high disease activity. Therefore, D-hypovitaminosis should be included in the differential diagnosis in patients with SLE presenting with low bone mass.

Adult↗
PubMed2001

GST fusion proteins cause false positives during selection of viral movement protein specific single chain antibodies.

Glutathione S-transferase (GST) fusion proteins are used frequently for investigating protein-protein and protein-DNA interactions. The present study demonstrates that the use of GST fusion proteins caused false positives during selection of phage-displayed single-chain antibody fragments (scFvs) specific for three domains of the movement protein (NS(M)) of tomato spotted wilt virus (TSWV). To identify and exclude the false positives when using GST as a fusion partner linked to the antigen of interest, indirect phage enzyme-linked immunosorbent assay (ELISA) was compared with capture phage ELISA. Of 210 enriched phage clones, indirect phage ELISA identified 106 clones specific for binding to GST-domain fusions but not to GST. In contrast, using capture phage ELISA, all 106 selected clones were identified as false positives, reacting with the GST fusion proteins and GST. This was confirmed by characterization of soluble scFv antibodies. The data indicate that GST fusion proteins seem unsuitable for screening of phage-displayed antibody fragments and it is essential to use capture phage ELISA, instead of the indirect phage ELISA used commonly to exclude false positives in characterization of selected clones with GST fusion proteins.

Animals↗
PubMed2001

Standardization of non-aggregated data: theory and practice.

Direct standardization of rates is a classical method in epidemiology by which the relationship between confounders and variables of analysis is balanced between the samples or populations to be compared. While the method is appropriate if single variables of aggregated data sets are to be compared, it is limited with respect to handling many variables of different measurement scale, especially in primary data situations. Therefore the method of direct standardization is adapted to the analysis of non-aggregated data. Computation of not only rates but other statistics of central tendency and dispersion as well as confidence intervals hence becomes feasible. In addition it is possible to re-adjust the primary data weights in order to perform stratified analyses. A procedure to do so, based solely on the available original weights without the need for analyzing the standard population is proposed along with an extensive SAS macro. The utility allows for the rapid and standardized analysis and tabulation of large multi-variable data sets. Both the statistical and technical properties of the macro are discussed and its usage is explained as well as exemplified.

Computational Biology↗
PubMed2001

Antibody-based resistance to plant pathogens.

Plant diseases are a major threat to the world food supply, as up to 15% of production is lost to pathogens. In the past, disease control and the generation of resistant plant lines protected against viral, bacterial or fungal pathogens, was achieved using conventional breeding based on crossings, mutant screenings and backcrossing. Many approaches in this field have failed or the resistance obtained has been rapidly broken by the pathogens. Recent advances in molecular biotechnology have made it possible to obtain and to modify genes that are useful for generating disease resistant crops. Several strategies, including expression of pathogen-derived sequences or anti-pathogenic agents, have been developed to engineer improved pathogen resistance in transgenic plants. Antibody-based resistance is a novel strategy for generating transgenic plants resistant to pathogens. Decades ago it was shown that polyclonal and monoclonal antibodies can neutralize viruses, bacteria and selected fungi. This approach has been improved recently by the development of recombinant antibodies (rAbs). Crop resistance can be engineered by the expression of pathogen-specific antibodies, antibody fragments or antibody fusion proteins. The advantages of this approach are that rAbs can be engineered against almost any target molecule, and it has been demonstrated that expression of functional pathogen-specific rAbs in plants confers effective pathogen protection. The efficacy of antibody-based resistance was first shown for plant viruses and its application to other plant pathogens is becoming more established. However, successful use of antibodies to generate plant pathogen resistance relies on appropriate target selection, careful antibody design, efficient antibody expression, stability and targeting to appropriate cellular compartments.

Antibodies, Viral↗
PubMed2001

Genetic evidence for a microtubule-destabilizing effect of conventional kinesin and analysis of its consequences for the control of nuclear distribution in Aspergillus nidulans.

Conventional kinesin is a microtubule-dependent motor protein believed to be involved in a variety of intracellular transport processes. In filamentous fungi, conventional kinesin has been implicated in different processes, such as vesicle migration, polarized growth, nuclear distribution, mitochondrial movement and vacuole formation. To gain further insights into the functions of this kinesin motor, we identified and characterized the conventional kinesin gene, kinA, of the established model organism Aspergillus nidulans. Disruption of the gene leads to a reduced growth rate and a nuclear positioning defect, resulting in nuclear cluster formation. These clusters are mobile and display a dynamic behaviour. The mutant phenotypes are pronounced at 37 degrees C, but rescued at 25 degrees C. The hyphal growth rate at 25 degrees C was even higher than that of the wild type at the same temperature. In addition, kinesin-deficient strains were less sensitive to the microtubule destabilizing drug benomyl, and disruption of conventional kinesin suppressed the cold sensitivity of an alpha-tubulin mutation (tubA4). These results suggest that conventional kinesin of A. nidulans plays a role in cytoskeletal dynamics, by destabilizing microtubules. This new role of conventional kinesin in microtubule stability could explain the various phenotypes observed in different fungi.

Amino Acid Sequence↗
PubMed2001

Expression of the peripheral-type benzodiazepine receptor and apoptosis induction in hepatic stellate cells.

BACKGROUND AND AIMS: Hepatic stellate cell (HSC) transformation and proliferation play an important role in liver fibrogenesis, and HSC apoptosis may be involved in the termination of this response. METHODS: Expression of the peripheral benzodiazepine receptor (PBR) and PBR-ligand-induced apoptosis were studied in cultured rat liver HSC. RESULTS: Transformation of HSC led to a transient expression of PBR at the messenger RNA and protein level, which was maximal after about 3 and 7 days of culture, respectively, and declined thereafter. Immunoreactive PBR showed a punctate staining and colocalized with mitochondrial manganese-dependent superoxide dismutase and adenine nucleotide translocator 1. The selective PBR ligands 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK11195) and 4' chlorodiazepam (Ro5-4864), but not the centrally acting benzodiazepine ligand clonazepam, induced dose-dependent apoptosis in HSC. The apoptotic potency of PK11195 paralleled the level of PBR expression. PK11195 induced dephosphorylation of protein kinase B/Akt and Bad and a downregulation of Bcl-2. Collapse of the mitochondrial membrane potential preceeded PBR-ligand-induced apoptosis. No apoptosis was induced by PK11195 in parenchymal cells, despite the presence of PBR, and PK11195 had no effect in these cells on Bad phosphorylation and Bcl-2 expression. CONCLUSIONS: Transformation of HSC leads to a transient expression of PBR and renders the cells sensitive to PBR-ligand-induced apoptosis, involving protein kinase B/Akt and Bad-dependent mechanisms.

Animals↗
PubMed2001

[Population-based health monitoring via computer-assisted telephone interviews in Bavaria].

From June 1999 until May 2000, 2051 computer-assisted telephone interviews concerning health and health related behaviours were assessed in Bavarian households. The aim of the study was the evaluation of the validity and representativity of this data by a comparison of selected variables from the Bavarian Mikrozensus-survey 1999. The distribution patterns of the marital status, the size of the households, the gainful employment, the household-netto-income, the school qualification and of the smoking status correspond well with those of the Mikrozensus 1999. As often found in questionnaire based surveys, a disproportionately high rate of participation of highly educated persons was observed. This led to an effect only in terms of a too small rate of persons with a low household-netto-income. Within the study, two different designs were compared. The commitment of the telephone numbers to a gender for an equal quotation of men and women led to an under-representation of single-households and therefore also of unmarried persons, but it had no effect on the other characteristics. The results of this study show, that the method of computer assisted-telephone interviews is a valid and cheap basis for the establishment of an exhaustive health surveillance system in Germany.

Adolescent↗
PubMed2001

Late recurrent saphenofemoral junction reflux after ligation and stripping of the greater saphenous vein.

OBJECTIVE: This study was done to determine the long-term incidence of refluxing epifascial-to-deep vein reconnections in the area of the former saphenofemoral junction after ligation of the true junction, along with all proximal tributaries, and resection of the greater saphenous vein. PATIENTS AND METHODS: A total of 125 limbs in 77 patients, representing 66% of 117 survivors among 602 patients who underwent operation between 1960 and 1967, were evaluated clinically and with duplex sonography for possible superficial-to-deep vein reconnections and clinical recurrence of thigh varicosities at a mean follow-up of 34 years. RESULTS: Clinical examination suggested saphenofemoral recurrence in 59 limbs (47%). In 11 instances these were actually varices associated with isolated superficial system reflux or reflux originating from a distally located perforating vein. Color-coded duplex ultrasonography demonstrated saphenofemoral reflux in 75 limbs (60%), versus the 48 identified on clinical examination (P <.001), and documented that the junction ligation had not been performed incorrectly by absence of the terminal valve or any patent proximal saphenous remnant. The reflux originated at the site of the ligated saphenofemoral junction in 53 limbs (71%) and from a nearby circumjunctional deep vein in the other 22 (29%). Of the real junctional recurrences, 22 appeared as a tangled cluster, and 31 involved a single-lumen varix. Only 27 recurrences were sufficiently symptomatic to warrant consideration of additional treatment; 25 of these were clinically evident, single-lumen, true junctional recurrences. CONCLUSIONS: This 34-year clinical follow-up study shows a 60% incidence of junctional and circumjunctional reconnections after ligation of the true saphenofemoral junction and its related tributaries. Color-coded duplex sonography is a necessary concomitant to clinical examination, detecting more recurrences and defining the pathologic anatomy to direct clinically indicated additional treatments.

Aged↗
PubMed2001

To blastocyst or not to blastocyst? That is the question.

Recent advances in culture media preparations have allowed for cleavage embryos to be developed to the blastocyst stage. Blastocysts are regarded as having increased implantation potential, and two blastocysts are typically transferred, which reduces the occurrence of high order multiple gestations. However, with current techniques, most cleavage embryos do not become blastocysts and it is not clear how many of these embryos would have implanted had they been replaced at the cleavage stage. Furthermore, experience with blastocyst cryopreservation is lacking and the overall benefit of blastocyst culture is unknown, unless we consider the combined pregnancy rates of both fresh and frozen blastocysts.

Blastocyst↗
PubMed2001

Effects of ultrapure dialysis fluid on nutritional status and inflammatory parameters.

BACKGROUND: Malnutrition and chronic systemic inflammatory response syndrome not only coexist in uraemia, but may also have a bi-directional cause-and-effect relationship. To evaluate the role of dialysate-related cytokine induction in inflammatory response and nutritional status, we conducted a prospective comparison of two dialysis fluids differing in their microbiological quality. METHODS: Forty-eight early haemodialysis patients were assigned to either treatment with conventional (potentially microbiologically contaminated) or on-line produced ultrapure dialysis fluid. Study parameters were bacterial growth, markers of systemic inflammation (C-reactive protein (CRP) and interleukin 6), and parameters of nutritional status (estimated dry weight, upper mid-arm muscle circumference, serum albumin concentration, insulin-like growth factor 1, leptin, and protein catabolic rate). Patients were followed for 12 months. RESULTS: There were no statistically significant differences in demographic and treatment characteristics, degree of bacterial contamination of the dialysate, markers of systemic inflammation, or parameters of nutritional status among the two treatment groups at recruitment. Changing from conventional to ultrapure dialysis fluid reduced significantly the levels of IL-6 (19+/-3 pg/ml to 13+/-3 pg/ml) and CRP (1.0+/- 0.4 mg/dl to 0.5+/-0.2 mg/dl), and resulted in significant increases in estimated dry body weight, mid-arm muscle circumference, serum albumin concentration, levels of the humoral factors, and in protein catabolic rate after 12 months. Continuous use of conventional dialysis fluid (median 40-60 c.f.u./ml) was not associated with significant alterations in markers of inflammation (IL-6 21+/-4 pg/ml vs 24+/-6 pg/ml, CRP 0.9+/-0.3 mg/dl vs 1.1+/-0.4 mg/dl) or of nutritional status at any time of the study. All differences in systemic inflammation and nutritional parameters observed during the study period (from recruitment to month 12) were significant between the two patient groups. CONCLUSIONS: Cytokine induction by microbiologically contaminated dialysis fluid has a negative impact on nutritional parameters of early haemodialysis patients. The microbiological quality of the dialysis fluid represents an independent determinant of the nutritional status in addition to known factors, such as dose of dialysis and biocompatibility of the dialyser membrane. Ultrapure dialysis fluid adds to the cost of the dialytic treatment, but may improve the nutritional status in long-term haemodialysis patients.

Aged↗
PubMed2001

Incomplete lupus erythematosus: results of a multicentre study under the supervision of the EULAR Standing Committee on International Clinical Studies Including Therapeutic Trials (ESCISIT).

OBJECTIVE: Patients characterized with antinuclear antibodies (ANA) and disease symptoms related to one organ system can be described as having incomplete systemic lupus erythematosus (SLE). The aim of this multicentre study was to describe the outcome of these so-called incomplete SLE patients. Two aspects of the outcome were studied: (i) the disease course, defined by the presence or absence of clinical symptoms; and (ii) the number of patients that eventually developed full SLE. METHODS: Outcome parameters were the ACR criteria, the SLE disease Activity Index (SLEDAI), the European Consensus Lupus Activity Measure (ECLAM) and the requirement for treatment. In 10 European rheumatology centres, patients who had been evaluated in the last 3 months of 1994 and had been diagnosed as having incomplete SLE on clinical grounds for at least 1 yr were included in the study. All 122 patients who were included in the study were evaluated annually during 3 yr of follow-up. RESULTS: Our results are confined to a patient cohort defined by disease duration of at least 1 yr, being under clinical care at the different centres in Europe. These patients showed disease activity that was related mostly to symptoms of the skin and the musculoskeletal system, and leucocytopenia. During the follow-up, low doses of prednisolone were still being prescribed in 43% of the patients. On recruitment to the study, 22 of the 122 incomplete SLE patients already fulfilled the ACR criteria for the diagnosis of SLE. In the 3 yr of follow-up only three patients developed SLE. CONCLUSIONS: A high proportion of patients in our cohort defined on clinical grounds as having incomplete SLE eventually showed disease activity defined by the SLEDAI as well as ECLAM. However, only three cases developed to SLE during the follow-up. This suggests that incomplete SLE forms a subgroup of SLE that has a good prognosis.

Adolescent↗
PubMed2001

Pantoprazole therapy in the long-term management of severe acid peptic disease: clinical efficacy, safety, serum gastrin, gastric histology, and endocrine cell studies.

OBJECTIVE: Pantoprazole is the third proton pump inhibitor to become available. When this study was started, there were few data on its long-term use. Our aim was to investigate this aspect and, because powerful inhibitors of acid secretion can cause hypergastrinemia and, in experimental animals, enterochromaffin-like cell hyperplasia, we also monitored serum gastrin and endocrine cell histology. METHODS: One hundred fifty patients refractory to H2-receptor antagonists, running an aggressive course or with complications, were entered into a 5-yr treatment program. We performed serial endoscopy, checked for adverse events, and laboratory values. We also monitored serum gastrin, gastric endocrine cell histology, and antral and corpus gastritis. RESULTS: This report presents results from up to 3 yr of treatment. Cumulative healing on 40-80 mg of pantoprazole was 82% at 4 wk and 92% by 12 wk. Most patients became asymptomatic within 4 wk. Remission on maintenance treatment with 40 mg (n = 111) was 85% at 12 months and 78% at 24 months. Treatment was safe; only four patients had adverse events definitely related to pantoprazole. Elevations in gastrin were modest and there were no significant changes in gastric endocrine cells. The number of enterochromaffin-like cells tended to decrease. CONCLUSION: Pantoprazole is effective, safe, and does not seem to be associated with large increases in serum gastrin or alterations in gastric endocrine cells.

2-Pyridinylmethylsulfinylbenzimidazoles↗