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Biomedical subjects

B Brückner

Publications and source records attributed to B Brückner.

At least 19 recordsLinked to original sources
PubMed2003

Efficacy and tolerance of a new gentamicin collagen fleece (Septocoll) after surgical treatment of a pilonidal sinus.

OBJECTIVE: Pilonidal sinus is common. It causes substantial loss of working hours. The major disadvantage of open wound treatment is the long time required for healing. Primary wound closure is on the other hand often followed by infection. A controlled, multicentre trial was carried out to evaluate the efficacy of a new gentamicin collagen fleece (Septocoll) combined with primary closure. PATIENTS AND METHODS: One hundred and three patients (88 men, 15 women, median age 30 years) were included. Fifty-one were randomised to gentamicin fleece plus primary closure (Genta Group), and 52 patients to open treatment alone (Open Group). RESULTS: The median interval to wound healing was 17 days in the Genta group and 68 days in the Open group (P = 0.0001, log-rank test). Two patients in Group 1 developed infection within the first two weeks, requiring reopening of the wound, with primary wound healing occurring in 73%. Failure of primary healing (27%) was usually due to seroma or spontaneous dehiscence which subsequently healed. CONCLUSION: The combination of gentamicin collagen fleece (Septocoll) with primary closure resulted in a shorter period to healing than the open technique without unwanted effects.

Adolescent↗
PubMed2000

[The evaluation by CT of bone block position, interference screw placement and replacement of the anterior cruciate ligament after patellar ligament transplantation].

PURPOSE: Evaluation of arthroscopically assisted reconstruction of the anterior cruciate ligament using ligamentum patellae autografts in the bone-tendon-bone technique with special regard to the position of blocks and interference screws. MATERIAL AND METHODS: In a prospective study 28 patients were included after undergoing arthroscopic anterior cruciate ligament replacement surgery. Data thus obtained were correlated with the postoperatively determined functional parameters of the affected joint. RESULTS: Interference screws, bone-blocks and ligamentous transplants could be well imaged using CT. In a comparison of our data with clinical results there was a statistically highly significant correlation between clinical outcome and the position of bone-blocks and interference screws in the tibia. Angles between screw and bone-block exceeding a standard deviation led to significantly worse results, while a divergence in femoral angles did not lead to significantly worse results. CONCLUSION: The postoperative study of anterior cruciate ligament replacement surgery by CT enables the evaluation of the transplant as well as the position of bone-blocks and interference screws.

Adult↗
PubMed1999

The nuclear distribution of Polycomb during Drosophila melanogaster development shown with a GFP fusion protein.

The chromatin protein Polycomb (PC) is necessary for keeping homeotic genes repressed in a permanent and heritable manner. PC is part of a large multimeric complex (PcG proteins) involved in generating silenced chromatin domains at target genes, thus preventing their inappropriate expression. In order to assess the intranuclear distribution of PC during mitosis in different developmental stages as well as in the germ line we generated transgenic fly lines expressing a PC-GFP (Green Fluorescent Protein) fusion protein. Rapidly dividing nuclei were found to display a rather homogeneous PC-GFP distribution. However, with increasing differentiation a pronounced subnuclear pattern was observed. In all investigated diploid somatic tissues the bulk of PC-GFP fusion protein is depleted from the chromosomes during mitosis: however, a detectable fraction remains associated. In the male germ line in early spermatogenesis, PC-GFP was closely associated with the chromosomal bivalents and gradually lost at later stages. Interestingly, we found that PC is associated with the nucleolus in spermatocytes, unlike somatic nuclei. In contrast to mature sperm showing no PC-GFP signal the female germ line retains PC in the germinal vesicle.

Animals↗
PubMed1998

Transgenic Drosophila expressing human amyloid precursor protein show gamma-secretase activity and a blistered-wing phenotype.

The importance of the amyloid precursor protein (APP) in the pathogenesis of Alzheimer's disease (AD) became apparent through the identification of distinct mutations in the APP gene, causing early onset familial AD with the accumulation of a 4-kDa peptide fragment (betaA4) in amyloid plaques and vascular deposits. However, the physiological role of APP is still unclear. In this work, Drosophila melanogaster is used as a model system to analyze the function of APP by expressing wild-type and various mutant forms of human APP in fly tissue culture cells as well as in transgenic fly lines. After expression of full-length APP forms, secretion of APP but not of betaA4 was observed in both systems. By using SPA4CT, a short APP form in which the signal peptide was fused directly to the betaA4 region, transmembrane domain, and cytoplasmic tail, we observed betaA4 release in flies and fly-tissue culture cells. Consequently, we showed a gamma-secretase activity in flies. Interestingly, transgenic flies expressing full-length forms of APP have a blistered-wing phenotype. As the wing is composed of interacting dorsal and ventral epithelial cell layers, this phenotype suggests that human APP expression interferes with cell adhesion/signaling pathways in Drosophila, independently of betaA4 generation.

Amyloid Precursor Protein Secretases↗
PubMed1995

Genetic variability in Gibberella fujikuroi and some related species of the genus Fusarium based on random amplification of polymorphic DNA (RAPD).

One of the most important rice pathogens is Fusarium moniliforme (perfect stage: Gibberella fujikuroi), the causal agent of the super-elongation ("bakanae") disease. Thirty-seven strains of this species from different geographical regions were analyzed for their ability to produce gibberellins (GA) and for genetic relatedness by random amplified polymorphic DNA (RAPD). All GA-producing isolates showed nearly identical RAPD patterns using 51 oligonucleotide nona- and deca-mers as arbitrary primers. On the other hand, large differences between GA-nonproducing isolates were obtained. Comparison of the RAPD patterns with those of the tester strains of the six known mating populations (A, B, C, D, E, F) of G. fujikuroi showed that all producer strains belong to mating population C and all nonproducer isolates to other mating populations. Evidence for the usefulness of the RAPD technique to distinguish between mating populations was provided by sexual crossings. Consensus phylogenetic trees based on RAPDs were constructed by the Phylogenetic Analysis Using Parsimony (PAUP) system. In combination with morphological analysis, RAPD can distinguish between different species of the genus Fusarium. These investigations may find an application in the diagnosis of unknown Fusarium spp. and in distinguishing isolates of G. fujikuroi within the section Liseola.

Base Sequence↗
PubMed1994

Variations in ploidy among isolates of Botrytis cinerea: implications for genetic and molecular analyses.

Field isolates and laboratory strains of Botrytis cinerea, an ascomycetous fungus causing considerable economic losses, e.g., as "grey mould" of vine, were compared for differences in ploidy level by determining their DNA content per nucleus. Strain SAS56, an ascospore line used routinely for genetic analyses, is probably polyploid, since treatment with benomyl causes a significant reduction in DNA content per nucleus. This conclusion is substantiated by the increased sensitivity of the putative haploid derivatives to mutagens (UV and EMS). Molecular analyses (RAPD) of the haploidized strains indicate a very limited degree of heterozygosis of the parent strain SAS56. Analysis of field isolates of B. cinerea showed that their DNA content per nucleus varied considerably, indicating that aneuploidy/polyploidy is a widespread phenomenon in this species. This can explain both the variability and phenotypic instability of many field isolates of this fungus and the unusual difficulties faced by researchers in recovering stable recessive laboratory mutants. Since the haploid derivatives of SAS56 resemble the parent strain in their parasitic and physiological properties they should provide a good basis for classical and molecular genetic studies.

Base Sequence↗
PubMed1992

Regulation of gibberellin formation by the fungus Gibberella fujikuroi.

Gibberellins are a classic example of the production of plant growth regulators by microorganisms. They are important biotechnological products and are increasingly used in agriculture and horticulture. The economic importance of these plant hormones has led to an extensive study of the regulation of gibberellin biosynthesis. There have been reports of light, growth rate, inoculum size and carbon and ammonium sources acting as regulators of gibberellic acid biosynthesis. Besides light stimulation, nitrogen repression is a well-known regulatory principle of secondary metabolite formation. In Gibberella fujikuroi ammonium interferes with the production of gibberellic acid whereas phosphate does not influence the biosynthesis. It was found that the negative effect of ammonium ions is due to both the inhibition of activity and the repression of de novo synthesis of specific gibberellin-producing enzymes. Besides nitrogen control, the biosynthesis of gibberellins is suppressed by glucose. This glucose effect can be overcome by the addition of mevalonic acid. Therefore, the key enzyme of the isoprenoid pathway, the HMG-CoA reductase, seems to be the target of C-catabolite repression. A detailed knowledge of the regulation of gibberellin biosynthesis is important for fermentation processes. The biological function of gibberellin formation for the producing fungus is discussed.

Carbon↗
PubMed1992

Transformation of Gibberella fujikuroi: effect of the Aspergillus nidulans AMA1 sequence on frequency and integration.

A stable and reproducible transformation selection system for Gibberella fujikuroi protoplasts based on the Aspergillus nidulans arg B gene, encoding ornithine transcarbamylase, has been developed. Inclusion into the vector of the A. nidulans DNA fragment (AMA1), which permits plasmid autonomous replication in A. nidulans, A. niger and A. oryzae, appeared to permit autonomous replication of G. fujikuroi although the transformation frequency was increased by only two-fold. Transformation was also achieved using the bacterial hygromycin B resistance gene under the control of G. pulicaris and A. nidulans promoters.

Arginine↗
PubMed1992

Obtaining mutants for protoplast fusion of gibberellin-forming Gibberella fujikuroi strains.

Auxotrophic, drug-resistant, nitrate-nonutilizing, and albino mutants have been isolated in Gibberella fujikuroi following UV mutagenesis. Protoplasts of complementing auxotrophic strains, mutants with resistance markers, or mutants blocked in different steps of the nitrate assimilatory pathway have been fused to form heterokaryons, diploids, or recombinant haploids. The properties of fusant strains, including gibberellic acid productivity, have been examined and compared to parent strains.

Cerulenin↗
PubMed1990

Size-dependent regeneration of Gibberella protoplasts.

Regeneration ratios of protoplasts formed from the plant pathogenic gibberella fujikuroi with a mixture of lytic enzymes were studied. The heterogeneous population of protoplasts was separated into groups differing in regeneration ratio. The frequency of regeneration was higher for large protoplasts containing an increased number of nuclei.

Cell Nucleus↗
PubMed1989

Fusarium moniliforme Sheld. A fungus producing a broad spectrum of bioactive metabolites.

Fusarium moniliforme Sheldon (perfect stage Gibberella fujikuroi (SAW. Wollenweber), an ubiquitous fungus belonging to the section Liseola (Booth), is one of the widespread, phytopathogenic fungi. This field fungus common on many crops, including rice, oats, wheat, maize, barley and soybeans was well known because of the ability to produce gibberellins in high quantities. Today beside of the very important gibberellic acid (GA3) other gibberellins such as GA4 and GA7 are of significance for agriculture and horticulture. Moreover, this fungus produces further biologically active metabolites, e.g. pigments, mycotoxins, phytotoxins, oestrogens and extracellular enzymes. Fusarium moniliforme strains are able to produce 2 pigment groups - the karotenoids and the bikaverins, the last of which has antibiotical activity against Leishmania brasiliensis. The biosynthesis of some mycotoxic substances, such as moniliformin, fusaric acid, fusarin C and fusariocin C, is described. From enzymes the milk-clotting rennin, cellulolytic and amylolytic enzymes, pectinases and phenol-degrading enzymes are of economical interest. Therefore, Fusarium moniliforme is a source of different bioactive metabolites. The production is dependent on the conditions and strain specifity.

Chemical Phenomena↗
PubMed1989

[Assessment of duodenogastric reflux with hepatobiliary functional scintigraphy].

The duodenogastric reflux was examined in 457 asymptomatic probands and patients with different diseases and postoperative conditions by means of the hepatobiliary functional scintigraphy. - The biliary reflux most frequently occurred in patients who had a gastric operation, in patients with gastroduodenal ulcers as well as with functionally conditioned biliary dyskinesia after cholecystectomy. - Aspects of a drug therapy were discussed for cases in which the duodenogastric reflux could be a facultative pathogenetic factor.

Adult↗
PubMed1985

[Effect of phosphate and inhibitors of protein synthesis on the growth and tentoxin production of Alternaria alternata (Fr.) Keissler].

The synthesis of a phytotoxic substance, tentoxin, by Alternaria alternata (Fr.) Keissler is negatively controlled by inorganic phosphate. We show here that the influence of phosphate on the production of this secondary metabolite is time-dependent. By using inhibitors of protein synthesis (p-fluorphenylalanine, cycloheximide) together with a resuspension technique, attempts were made to find out when the enzymes responsible for tentoxin synthesis are formed.

Alternaria↗
PubMed1985

[Effect of acetate on the formation of the phyoeffector tentoxin by Alternaria alternata (Fr.) Keissler].

The effect of the cosubstrate acetate on the formation of the phytotoxic substance tentoxin by Alternaria alternata (Fr.) Keissler was investigated. Acetate was taken up and metabolized during growth. The added acetate stimulated considerably the biosynthesis of tentoxin depending on its concentration and time of introduction. There was an increased incorporation of (U-14C)-glucose into the toxin molecule in the presence of acetate in the medium. The results indicate an induction of the biosynthesis of tentoxin by the precursor acetate, probably mediated through the accumulation of the glycolytic intermediates pyruvate and phosphoenolpyruvate.

Acetates↗
PubMed1984

Effect of disulfiram on N-nitroso-N-methylbenzylamine metabolism. Biochemical aspects.

The present biochemical experiments show that disulfiram inhibits N-nitroso-N-methylbenzylamine metabolism in the rat. More N-nitroso-N-methylbenzylamine may therefore reach extrahepatic tissues. The pathological lesions observed in the lungs in the present system can be explained by the finding that alkylation of lung DNA is increased and repair processes are impaired by enhanced cell proliferation in this organ.

Animals↗
PubMed1984

Role of the respiratory system in metabolism of N-nitrosamines after simultaneous application of disulfiram.

Subsequent to modification of N-nitrosamine metabolism by disulfiram, mucus-producing cells and Clara cells in the respiratory tract are involved increasingly in detoxification as well as in bioactivation of N-nitroso-N-methylbenzylamine and N-nitrosodibutylamine. Overtaxing of these cells or local concentration of antigenic metabolites leads to cytolytic defects in tracheal, bronchial and bronchiolar epithelium, in addition to toxic degenerative lesions. The resulting continuous stimulation of proliferation leads to basal-cell hyperplasia, squamous-cell metaplasia and squamous papillomas. In areas with insufficient differentiation, due to cell proliferation, there is an increased probability that focal mutation, subsequent to alkylation of purine bases, will be passed from one cell generation to the next, with subsequent formation of tumours in the bronchiolo-alveolar region.

Animals↗