Biomedical subjects

M Köller

Publications and source records attributed to M Köller.

At least 73 records · Page 4Linked to original sources

PubMed1991

Serum CD14 levels in polytraumatized and severely burned patients.

Recently it has been demonstrated that the CD14 molecule which is expressed on monocytes and macrophages serves as a receptor for lipopolysaccharide (LPS) bound to LPS-binding protein (LBP) and thus mediates LPS-induced tumour necrosis factor (TNF) production. Here we report that CD14 is found as a soluble (s) molecule in serum. In healthy volunteers sCD14 levels (mean +/- s.e.m.) were 3.7 +/- 0.05 micrograms/ml (n = 30, 25-50 years of age) as determined by ELISA (detection limit 20 ng/ml serum) using two monoclonal antibodies in a sandwich technique. In polytraumatized patients (n = 16) significantly decreased levels (1.7 +/- 0.3) were detected immediately after the trauma, which increased to 4.9 +/- 0.3 micrograms/ml within the first 6 days post trauma. sCD14 remained elevated during the first 14 days post trauma in patients with the most severe injuries (injury severity score greater than 45 points), whereas a return to normal levels was observed in patients with an injury score of less than 45 points. In addition, the levels of the high-density lipoproteins that partially inactivate free endotoxin are significantly decreased post trauma. No correlation between parameters of inflammation (C3a and neopterin levels, leucocyte counts, amount of band cells), liver function and sCD14 levels was established. Comparable to polytraumatized patients, increased sCD14 serum levels were observed in five patients with burn trauma (burned area greater than 35%) within the second week post trauma when clinical signs of septicaemia were evident.

Adolescent↗

PubMed1991

Regulation of leukotriene B4 generation from human polymorphonuclear granulocytes after stimulation with formyl-methionyl-leucyl phenylalanine: effects of pertussis and cholera toxins.

The effects of holotoxins and toxin subunits from Bordetella pertussis and Vibrio cholerae strains on intact and digitonin-permeabilized human polymorphonuclear neutrophils were studied. Our data clearly demonstrate that formyl-methionyl-leucyl-phenylalanine (fMLP)-induced generation of chemotactic active leukotriene B4 was inhibited by both holotoxins as well as by their isolated enzymatic A protomers. In contrast, the respective binding components (B oligomers) did not affect leukotriene formation. Priming of digitonin-permeabilized neutrophils with either guanylylimidodiphosphate or inositol trisphosphate increased subsequent stimulation with fMLP. In contrast, diacylglycerol decreased fMLP-induced leukotriene B4 formation, but inositol trisphosphate and diacylglycerol had no effect on inhibition mediated by the toxins. In addition, pertussis and cholera toxins reduced the specific binding of [3H]fMLP. Scatchard plot analysis revealed that the observed decrease of peptide binding was due to a reduced number of receptor sites. The fMLP-stimulated [3H]guanylylimidodiphosphate binding and GTPase activity used as parameters for the activation of G proteins were decreased in parallel. These results suggest altered chemotactic receptor numbers and G-protein functions responsible for the toxin-dependent suppression of fMLP-mediated response for neutrophils.

Cholera Toxin↗

PubMed1991

Differential regulation of T- and B-lymphocyte activation in severely burned patients.

We studied the in vitro expression and regulation of the CD23 and CD25 (Tac) surface antigens by peripheral blood lymphocytes (PBL) from severely burned patients (burn injuries ranging from 25% to 72% TBSA) in order to evaluate T- and B-lymphocyte activation processes after thermal trauma. The spontaneous and cytokine (IL-4, IL-2)-induced expression of CD23 which represents a B-cell activation marker was significantly reduced during the second to fifth week postburn when compared to healthy donors. In contrast, CD25, which is expressed on activated T cells, showed a marked increase both spontaneously, indicating an in vivo activation, and after stimulation with IL-2 or PHA. Concomitantly, T-cell proliferation induced by PHA or Con A was suppressed. However, the number of T and B cells remained unchanged. The data demonstrate the impairment of early events in the lymphocyte program in severely burned patients. The activation of B cells is downregulated, since they become refractory to external helper signals. In addition, T cells are highly activated but fail to proceed to proliferation in response to mitogenic stimuli.

Adult↗

PubMed1991

[Microbial pathogenicity factors and host defense mechanisms--parameters of post-traumatic infections].

The clinical features of posttraumatic infections are due to the interactions between microbial pathogenicity factors and the host defense. The virulence mechanisms of microorganisms include the adherence, chemotaxis, invasion, resistance, and production of toxins. In addition, the humoral and cellular components of the immune system are impaired in trauma patients. The influence of pathogenic microorganisms on immune effector cells results in the release of various inflammatory mediators which participate in the protective host response to infection but induce local and systemic damage provided they are excessively produced and/or ineffectively metabolized.

Bacteria↗

PubMed1990

Basophil releasability in severely burned patients.

Thermal injury is known to induce dysregulation of the immune system; however, the precise mechanisms have to be clarified. We investigated the histamine release of basophil granulocytes from severely burned patients (n = 12) after stimulation with anti-IgE or the Ca-ionophore A 23187, respectively. The anti-IgE-induced basophil histamine release of all patients was reduced in comparison to healthy donors beginning at day one postburn (p.b.) (5.0 +/- 2.3% vs. 30.5 +/-3.4%), while the Ca-ionophore-induced release was not decreased before day two p.b. Basophils of patients who finally succumbed to their injuries showed poor responsiveness (to zero levels) over the total time. In contrast, the basophil releasability of surviving patients returned to nearly normal levels (fifth to seventh week p.b.). Already in the second week p.b. there was a significant difference in histamine release between survivors and nonsurvivors [e.g., days 6-9 p.b.: 23.7 +/- 4.0 vs. 6.9 +/- 2.7 (p less than 0.005) after Ca-ionophore stimulation]. The altered basophil histamine release was neither due to a diminished dose- or a delayed time-response to the stimuli nor due to differences in the basophil counts or the cellular histamine content. Our data indicate that the decrease of the basophil releasability, which may be secondary to altered signal transduction pathways in severely burned patients correlates with the clinical outcome.

Adult↗

PubMed1990

Studies on B-lymphocyte dysfunctions in severely burned patients.

We studied in vitro functional parameters of peripheral blood B-lymphocytes from severely burned patients (n = 10; burn injuries ranging from 25 to 72% TBSA). While the number of B-cells remained unchanged, B-cell proliferation induced by Staphylococcus aureus strain Cowan I (SAC) was normal or even enhanced at early and late phases postburn, but showed a marked suppression during the second to fourth week. A similar pattern was observed for the pokeweed mitogen (PWM)- or SAC-stimulated synthesis of immunoglobulin M (IgM), whereas IgG production was decreased over the whole postburn period monitored. Cytokine (interleukin 4)-induced B-cell activation as indicated by the expression of the CD23 surface antigen was impaired throughout the second to fifth week. In parallel, the release of the proteolytic cleavage product sCD23 which represents a B-cell growth and differentiation factor was reduced. Our data provide evidence that activation, proliferation, and differentiation processes of B-lymphocytes are impaired in severely burned patients, which may contribute to their enhanced susceptibility to infection and sepsis.

Adult↗

PubMed1990

Metabolism of platelet activating factor (PAF) and lyso-PAF in polymorphonuclear granulocytes from severely burned patients.

We studied the metabolism of 3H-platelet activating factor (PAF) and lyso-PAF in human polymorphonuclear granulocytes (PMN) from severely burned patients (n = 6) on days 1, 5, 9, 15, and 25 post-trauma. All patients suffered from a severe burn trauma of more than 30% total body surface area. Stimulation of PMN in healthy donors (n = 10) with the Ca-ionophore resulted in the conversion of 3H-lyso-PAF into PAF (18 +/- 2% of total radioactivity) and alkyl-acyl-glycero-phosphorylcholine (alkyl-acyl-GPC, 50 +/- 6%). In burned patients a significantly reduced formation of 3H-PAF was observed between days 1 and 15 post-trauma (day 9: 1 +/- 1%, p less than 0.0001). This pattern was normalized again in patients (n = 5) who survived the trauma after septic periods and was observed during the second week post-trauma. In one patient who succumbed to his injuries a sustained inhibition of PAF formation was observed up to his death. The decreased formation of PAF correlated weakly with the appearance of immature granulocytes within the analyzed cell fraction (ratio of immature cells versus PAF-formation, r = -0.55, p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Arachidonic acid metabolism in heat-shock treated human leucocytes.

Human neutrophil granulocyte fractions (PMN) and lymphocytes/monocytes/basophils (LMB) were stimulated with A23187 (7.3 microM), opsonized zymosan (1 mg) or FMLP (10(-5) M) after heat-shock treatment. We observed a temperature- (pretreatment over 40 degrees) and time-dependent (incubation periods longer than 20 min) suppression in the generation of LTB4, LTB4 metabolites and isomers, as well as LTC4 and 5-HETE. These effects were not reversed after the addition of exogenous arachidonic acid (AA;50 microM). In contrast, heat-shock treatment alone triggered platelets to generate 12-HETE. After 1 hr at 42 degrees, 135 +/- 24 ng of 12-HETE were generated from 1 x 10(8) cells. The 12-HETE generation was not dependent on extracellular Ca2+. Conversion of 14C-AA (2 nmol) revealed an enhanced metabolism of AA to 12-HETE by platelets after heat-shock treatment without exogenous Ca2+. PMN and LMB labelled with 35S-methionine led to heat-shock protein (HSP; 65,000, 83,000 MW) expression after heat-shock treatment at 42 degrees or in the presence of NDGA (1 x 10(-5) M) at 37 degrees. These results suggest a regulatory interaction between the generation of lipo-oxygenase products, cellular stress responses and the expression of HSP.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1990

The neutrophil and leukotrienes--role in health and disease.

The granulocyte plays a major role in inflammatory processes by its capability to produce and release proinflammatory mediators such as the leukotrienes. This class of mediators exerts multiple functions in various physiological and pathophysiological processes. The interdependent interaction among the various mediator cascades, the inflammatory cells as well as the neuroendocrine system are areas of current interest. Appropriate stimuli (immunological, non immunological) by their defined pattern of signal transduction are responsible for priming, cellular activation and deactivation of granulocytes as it is shown for microbial infection. Thus the mediators may provide the prerequisites for a balanced homeostasis during host defense. It is clear that among the complexity of mediators not a single factor but the interaction of multiple mediator cascades reflect the final outcome of the disease process. In this regard the actual concentrations at local sites are obviously more relevant as those in whole body fluids.

Humans↗

PubMed1989

Heat shock induces alterations of the lipoxygenase pathway in human polymorphonuclear granulocytes.

We have investigated the effect of the heat shock response on the leukotriene generation, chemotaxis, and generation of oxygen radicals of human polymorphonuclear granulocytes (PMNs) by preincubating the PMNs at 42 degrees C. Subsequently, the different test systems were performed at 37 degrees C. As we confirmed by the release of lactate dehydrogenase and beta-glucuronidase the elevated temperatures did not result in cytotoxic or degranulating processes. After heat shock treatment the generation of leukotrienes induced by the Ca(++)-ionophore A23187, fMLP or opsonized zymosan was inhibited in a time and temperature dependent manner (preincubation phase) as was measured by HPLC-analysis. In contrast, the conversion of 14C-arachidonic acid revealed the generation of LTB4, 5-HPETE and 5-HETE solely as a result of the preincubation at 42 degrees C without any further stimulation. In addition, the chemiluminescence response induced by opsonized zymosan and the chemotaxis against C5a and LTB4 was clearly inhibited after heat shock treatment. With regard to enzyme activities of the heat treated PMNs the protein kinase C activities were enhanced whereas the LTD4-dipeptidase and the LTB4-omega-hydroxylase were not affected.

Chemotaxis, Leukocyte↗

PubMed1989

Studies on the mechanisms of granulocyte dysfunctions in severely burned patients--evidence for altered leukotriene generation.

The leukotriene generation (LTB4, 20-OH-LTB4, 20-COOH-LTB4) from PMNs of severely burned patients (n = 6) was studied by reversed-phase HPLC. Granulocytes from all patients showed a decrease in leukotriene generation which only returned to normal levels when the patients recovered from their injuries. The leukotriene generation induced by different stimuli, i.e., the Ca++-ionophore A23187 (7.3 microM) or opsonized zymosan (2 mg) in the presence of exogenous arachidonic acid (60 microM) showed similar stimulation profiles. The cellular differentiation of the respective granulocyte fractions revealed that the decreased leukotriene generation was accompanied by the occurrence of immature granulocytes in the peripheral blood. Furthermore, the studies in the presence of exogenous arachidonic acid showed that the defect in leukotriene generation from granulocytes of surviving patients was due to the availability of metabolizable substrate (i.e., free arachidonic acid). Granulocytes from one nonsurviving patient showed in addition a defect in the metabolic ability of arachidonic acid to generate the respective leukotrienes. The generation of reactive oxygen species did not correlate with the observed alterations in the formation of the leukotrienes.

Adult↗

PubMed1989

Induction of inflammatory mediators (histamine and leukotrienes) from rat peritoneal mast cells and human granulocytes by Pseudomonas aeruginosa strains from burn patients.

Clinical isolates of Pseudomonas aeruginosa from severely burned patients were analyzed with regard to their capacity to induce inflammatory-mediator release from rat mast cells or human granulocytes. The bacterial strains were characterized according to their cell-associated hemolysin activity as well as their secreted hemolysin and phospholipase C activities. P. aeruginosa expressing heat-labile hemolysin and phospholipase C induced histamine release from rat mast cells and leukotriene formation from human granulocytes, while bacterial strains expressing heat-stable hemolysin were potent releasers of histamine but did not lead to leukotriene formation. The mediator-inducing capacity was dependent on the growth characteristics of the bacterial strains. The purified glycolipid (heat-stable hemolysin) of P. aeruginosa was a potent inducer of histamine release but did not initiate leukotriene formation. Exotoxin A did not affect inflammatory-mediator release. P. aeruginosa with leukotriene-inducing capacity also enhanced omega oxidation of endogenous leukotriene B4, suggesting an additional inactivation of the chemotactic potential. Our data suggest that both hemolysins of P. aeruginosa contribute to the pathogenicity of P. aeruginosa by inducing and modulating inflammatory-mediator release from various cells.

Adjuvants, Immunologic↗

PubMed1989

Effect of sodium fluoride on the generation of lipoxygenase products from human polymorphonuclear granulocytes, mononuclear cells and platelets--indication for the involvement of G proteins.

Incubation of human polymorphonuclear granulocytes, monocytes and platelets with sodium fluoride (NaF) results in a time- and dose-dependent generation of leukotrienes and 12-HETE, respectively. This release was not influenced by pretreatment with pertussis toxin or cholera toxin. The mediators are detectable after a lag phase of about 5-10 min. Inactivation of LTB4 by the neutrophils via omega-oxidation into 20-hydroxy-LTB4 and 20-carboxy-LTB4 is inhibited by NaF. In combination with other cell stimuli, NaF showed modulatory effects, such as an enhanced formation of the leukotrienes when FMLP, opsonized zymosan, PMA, and arachidonic acid were applied as stimuli. Prestimulation of cells with NaF causes an increased [3H]guanylylimidodiphosphate binding to isolated membrane preparations, indicating an enhanced exchange rate for GDP to GTP. Our data demonstrate that a direct activation of GTP-binding proteins results in the generation of the inflammatory mediators and provides evidence for the involvement of the signal-transduction pathway.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1988

Arachidonic acid metabolites from polymorphonuclear leukocytes of healthy donors, severely burned patients and children with cystic fibrosis--routine monitoring by high-performance liquid chromatography.

A rapid and sensitive high-performance liquid chromatographic method for the determination of arachidonic acid metabolites was developed. This method provides a clear and simple separation of the omega-oxidation products as well as of leukotriene B4 and 5S,12S-dihydroxy-6-cis-8-trans-10-trans-14-cis-eicosatetraenoic acid. Furthermore, a solvent switch enables the detection of the monohydroxyeicosatetraenoic acids together with the cysteinyl-leukotrienes as well as leukotriene B4 and the dihydroxyeicosatetraenoic acids within 70 min (including column equilibration for 10 min). The efficiency of the method for the routine monitoring of leukotrienes was performed with human polymorphonuclear leukocytes of healthy donors, severely burned patients and of children with cystic fibrosis. The advantages of this method include high sensitivity and easy handling, which are important for routine analyses of the arachidonic acid metabolites.

Arachidonic Acids↗

PubMed1988

Application of high-performance liquid chromatography of some antibiotics in clinical microbiology.

During recent years high-performance liquid chromatography has become an excellent tool for the determination of antibiotics in biological fluids. Compared with biological assays, the major benefits of this method are specificity and rapidity. In particular, the determination of biologically inactive metabolites emphasizes that this technique plays an outstanding role for the analysis of antibiotics. This paper describes how the method can be used in the analysis of several antibiotics and demonstrates the efficacy of this method for clinical microbiology. Methods for the determination in biological fluids of acylaminopenicillins (azlocillin, mezlocillin, piperacillin and aspoxicillin), quinolones (ciprofloxacine, norfloxacine and ofloxacine), a penem (imipenem) and a cephalosporin (cefixime) are summarized. Furthermore, their application to in vitro studies and their trial in clinical studies are described.

Anti-Bacterial Agents↗

PubMed1988

Decreased expression of leukotriene B4 receptor sites on polymorphonuclear granulocytes of severely burned patients.

Polymorphonuclear granulocytes were isolated from patients with burn injury and the specific binding of (3H)leukotriene B4 was assessed. We observed a decreased receptor expression as compared to healthy donor cells, which may be the result of receptor downregulation as a consequence of cellular preactivation. In addition, leukotriene B4-synthesis was also reduced and differential cell counts demonstrated a shift from segmented neutrophils to immature cells. In survivors the values returned to normal parameters whereas nonsurvivors who succumbed in the course of generalized sepsis showed depressed cellular functions up to their death.

Burns↗

PubMed1988

Generation of leukotrienes from human polymorphonuclear granulocytes of severely burned patients.

The Ca ionophore A23187-induced leukotriene (LT) release (LTC4, LTB4, 20-OH-LTB4, 20-COOH-LTB4) of human PMN's from severely burned patients (n = 6) was studied by reversed-phase HPLC. The patients' granulocytes demonstrated a decrease (to zero levels) in LT generation postburn. The level of generated LT's resembled that of healthy donors when the patients recovered from their trauma (after day 40 postburn). In contrast, the granulocytes of patients who finally succumbed to their injuries showed poor responsiveness over the total time. An enhanced LTC4 production by granulocytes correlated with an increase in eosinophils within the granulocyte fraction. In addition, the reduced LTB4 production was accompanied by an enhanced LTB4 metabolism to biologically less active products (omega-oxidated metabolites). Thus, the capacity of patients' PMN's to release chemotactic substances was further decreased. The onset of this PMN dysfunction correlated with the onset of invasive microbial growth as determined by the quantitative bacterial analysis of full-thickness biopsy specimens. Our data provide evidence that the altered mediator release of patients' PMN's is closely related to a depressed host defense.

Adult↗

PubMed1988

Tumour necrosis factors modulate the affinity state of the leukotriene B4 receptor on human neutrophils.

Pre-incubation of human polymorphonuclear granulocytes with recombinant human tumour necrosis factors (TNF) revealed a time- and dose-dependent reduction of the expression of leukotriene B4-receptor sites. Analysis of the binding data by Scatchard plots showed a shift from a heterologous receptor population (indicating high- and low-affinity subsets) to a homologous population. From the results it is considered that TNF can influence host defence through the modulation of leukotriene B4 receptor affinity.

Dose-Response Relationship, Immunologic↗