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Biomedical subjects

F Espersen

Publications and source records attributed to F Espersen.

At least 145 records · Page 8Linked to original sources
PubMed1986

Staphylococcus aureus endocarditis. A review of 119 cases.

Staphylococcus aureus endocarditis cases in Denmark from 1976 to 1981 were reviewed. A total of 119 patients--61 female and 58 male, with a median age of 63 years (range, 1 month to 85 years)--fulfilled the diagnostic criteria. Community-acquired infections were most common (62%), but the frequency of hospital-acquired cases (38%) was greater than in earlier reports. The clinical picture was relatively nonspecific, and 32% of the patients had no heart murmurs initially. In 65 cases (55%), endocarditis was not suspected clinically, and the diagnosis was first obtained at autopsy. The mortality was 71% and correlated with age, hospital-acquired infection, and the presence of heart failure and arterial embolism.

Adolescent↗
PubMed1985

Bacteria-induced histamine release. Examination of the bacterial cell wall components peptidoglycan, teichoic acid and protein A.

The histamine-releasing capability of whole bacteria was examined in leukocyte suspensions from normal individuals. Both gram-positive and gram-negative bacteria caused basophil histamine release. It is probably the bacterial cell wall which interacts with the basophil cell surface leading to release of histamine, since cell walls showed higher histamine releasing capability than the whole bacteria. The releasing effect of the bacterial cell wall components peptidoglycan, teichoic acid and protein A was examined. The peptidoglycan preparations were found to be more potent than the corresponding whole bacteria and cell walls. Since peptidoglycan is found in the cell wall of both gram-positive and gram-negative bacteria, it might be a common factor responsible for histamine release by different bacteria. No release was obtained by teichoic acid, whereas protein A caused histamine release in leukocytes from allergic patients, but only a poor release in normal individuals. The initial step in protein A-induced histamine release might be a binding of protein A to IgE on the cell surface, since removal of cell-bound IgE reduced the release and a high correlation was found between protein A- and anti-IgE-induced histamine release.

Bacterial Physiological Phenomena↗
PubMed1985

Stomatococcus mucilaginosus endocarditis.

A case of non-nosocomial, spontaneously occurring endocarditis caused by growth of Stomatococcus mucilaginosus on a prolapsed mitral valve is reported. Despite the organism's high susceptibility in vitro the patient responded slowly to antibiotic treatment. Colony adherence to agar surface and absent or weak catalase reaction differentiated this gram-positive coccus from coagulase-negative staphylococci and micrococci.

Endocarditis↗
PubMed1985

In-vitro activity of methicillin against clinical isolates of Staphylococcus aureus.

Methicillin activity against 149 penicillin-resistant, methicillin-susceptible Staphylococcus aureus strains from bacteraemia cases with endocarditis (n = 89) or without endocarditis (n = 60), from the years 1976-1981, was studied with broth dilution and agar dilution. While no differences in methicillin susceptibility were found in relation to the origin of the strains, Staph. aureus of the phage type complex 94,96 showed significantly higher MIC and IC50 by agar dilution than strains of other phage groups/complexes. This difference probably has no clinical importance but is of epidemiological interest. Broth dilution MIC was generally one dilution higher than agar dilution MIC, possibly explained by methodological factors. The MBC/MIC ratios never exceeded two in any of the strains, indicating a lack of tolerance in these clinically important isolates.

Bacteriophage Typing↗
PubMed1985

Antibody response against whole Staphylococcus aureus in patients with staphylococcal septicaemia and endocarditis investigated by ELISA.

A whole cell Staphylococcus aureus enzyme-linked immunosorbent assay (ELISA) for the detection of IgG antibodies against S. aureus has been developed. To avoid non-specific binding of IgG to protein A, the protein A-poor strains of S. aureus, E 1369 and Wood 46, were used as antigens. One-hundred and eighty serum samples from 120 patients with S. aureus endocarditis, non S. aureus endocarditis, S. aureus septicaemia and non S. aureus septicaemia were tested together with sera from 155 healthy controls. The sensitivity was similar for the E 1369 ELISA and the Wood 46 ELISA and positive test values were detected in 84.2% of patients with S. aureus endocarditis and 41.2% of patients with complicated S. aureus septicaemia. No distinction could be found between complicated and uncomplicated S. aureus septicaemia. The E 1369 ELISA was more specific showing cross reactions with sera from patients infected with other bacteria than S. aureus in 3.6%. Furthermore, the reproducibility was better for the E 1369 ELISA with a coefficient of variation at 0.054. The absence of need for purified antigens makes the whole S. aureus ELISA easy, rapid and cheap. Therefore, we suggest the whole S. aureus ELISA as a good alternative to previously reported assays using purified cell wall antigens.

Adolescent↗
PubMed1985

Immunization of mice with the fibronectin-binding protein and clumping factor from Staphylococcus aureus: antibody response and resistance against intraperitoneal infection.

The antibody response against Staphylococcus aureus antigens was quantitated in mice immunized with live staphylococci, the fibronectin-binding protein, clumping factor, or saline by means of enzyme-linked immunosorbent assay. Immunization with purified clumping factor induced a significant increase in antibody levels, while the fibronectin-binding protein gave a poor response. All mice immunized with live S. aureus developed a high antibody level. The immunization of mice with live S. aureus or clumping factor resulted in an increased resistance towards staphylococcal intraperitoneal infection.

Animals↗
PubMed1985

Complement activation by clumping factor and protein A from Staphylococcus aureus strain E 2371.

Purified surface components from Staphylococcus aureus strain E 2371, which bind to human plasma proteins, were tested for their ability in vitro to activate complement present in normal human serum. Staphylococcal clumping factor as well as protein A both isolated from strain E 2371 were capable of activate complement, while the fibronectin-binding protein showed no activity. At identical molar concentrations clumping factor was more potent than protein A to induce complement consumption. Both clumping factor and protein A were able to activate the alternative complement pathway as demonstrated in serum chelated with ethylene-glycerol-tetra-acetic acid (10 mM) in the presence of MgCl2 (10 mM).

Chromatography, Affinity↗
PubMed1985

Isolation of Staphylococcus aureus clumping factor.

Immunochemically identical components were isolated from water-soluble phases of five Staphylococcus aureus strains by affinity chromatography on fibrinogen-linked Sepharose 4B. The elution was performed with 1 M MgCl2. The component could be isolated from sonicated preparations of whole cells, cell walls, and extracellular products of S. aureus but not from sonicated preparations of staphylococcal L-forms or from Staphylococcus epidermidis. Investigations of the eluted component by immunoelectrophoresis and Western blot analysis by use of different polyspecific antibodies to S. aureus raised in rabbits revealed only one immunoprecipitate or one band. By means of gel filtration on Sepharose CL 6B and sodium dodecyl sulfate-polyacrylamide gel electrophoresis a molecular mass of 420,000 and 360,000 was found, respectively. Chemical analysis showed a carbohydrate content of about 20% by weight. By crossed immunoelectrophoresis the isolated component was demonstrated to bind to human fibrinogen. The finding that this purified component inhibited the fibrinogen-induced clumping of staphylococci strongly suggests that the component is the S. aureus clumping factor.

Animals↗
PubMed1985

Interaction between limulus amoebocyte lysate and soluble antigens from Pseudomonas aeruginosa and Staphylococcus aureus studied by quantitative immunoelectrophoresis.

To investigate the interaction of Limulus amoebocyte lysate (LAL) with gram-negative bacteria, soluble antigens from sonicated Pseudomonas aeruginosa were studied by various crossed-immunoelectrophoresis methods before and after reaction with LAL. Of 64 possible, at least 7 antigens were affected, as indicated by precipitin pattern, after the reaction with LAL. The precipitates corresponding to lipopolysaccharide and Pseudomonas "common antigen" disappeared. This reaction was inhibited when LAL was pretreated with lipopolysaccharide or by heating. Several of the reacting antigens have been shown to cross-react with many other strains of both gram-negative and gram-positive bacteria. Soluble antigens from a protein A-deficient strain of Staphylococcus aureus were also studied. LAL reacted with at least four of these antigens, including the teichoic acid complex. It is concluded that LAL is highly reactive with lipopolysaccharide, but it can react with other antigens from gram-negative and gram-positive bacteria as well. It is suggested that LAL interacts with biologically important antigens from the bacterial membrane. It is proposed that the reactivity and specificity of LAL for various microbial antigens can be studied by immunoelectrophoretic techniques.

Antigens, Bacterial↗
PubMed1985

Serological assays against Staphylococcus aureus peptidoglycan, crude staphylococcal antigen and staphylolysin in the diagnosis of serious S. aureus infections.

Immunoglobulin G antibody levels against Staphylococcus aureus peptidoglycan (PG) and crude staphylococcal antigen (SA) using enzyme-linked immunosorbent assay (ELISA) and antistaphylolysin (ASTA) antibody levels by gel diffusion were determined in 53 patients with S. aureus and 54 patients with non-S. aureus endocarditis and septicemia as compared with 63 febrile control patients. The two ELISAs were the most sensitive assays indicating S. aureus endocarditis in 83% and 88% in the PG- and SA-assays, respectively. 39% of non-S. aureus endocarditis patients were positive in the PG-assay due to antibodies cross-reacting with streptococci. A 100% specificity for S. aureus infections was obtained with the ASTA test, but this assay was less sensitive. A significant rise in anti-PG or anti-SA antibody levels was not only seen among S. aureus infections but also in some streptococcal and S. epidermidis infections as well as in 3 febrile control patients. When at least 2 of the 3 assays showed positive peak antibody levels 1-4 weeks after onset of infection together with a significant rise of both anti-PG and anti-SA antibody levels the S. aureus endocarditis diagnosis was highly suggestive. Thus, we recommend the combined use of these 3 assays using paired serum samples in diagnosing serious S. aureus infections.

Adolescent↗
PubMed1984

Lectin-mediated reactions in histamine release caused by bacteria.

The bacteria-induced release of histamine was studied in human basophil leukocytes and in isolated rat mast cells. Whole bacteria of Staph. aureus caused release in a 98% pure population of peritoneal mast cells from germ-free rats, indicating a non-immunological mechanism and a direct interaction between the bacteria and the target cells. Probably the bacterial cell wall interacts with the cell membrane, since a preparation of the bacterial cell wall caused a dose-dependent release of histamine from basophil leukocytes similar to that induced by whole bacteria, and repeated washing of whole bacteria did not change the release. Inhibition studies by lectin-binding sugars indicate that aminosugars on the bacterial surface of Staph. aureus interact with lectins on the basophil cell membrane leading to histamine release.

Adult↗
PubMed1984

Opsonic activity of fibronectin in the phagocytosis of Staphylococcus aureus by polymorphonuclear leukocytes.

The effect of the opsonic activity of human purified fibronectin on phagocytosis of Staphylococcus aureus by human polymorphonuclear leukocytes was investigated. After opsonization with fibronectin there was a significant increase in the rate of phagocytosis of four out of six Staphylococcus aureus strains. Both attachment to and ingestion by leukocytes was affected, as revealed by lysostaphin treatment. Incubation of leukocytes with fibronectin prior to phagocytosis did not enhance the phagocytosis of Staphylococcus aureus. This shows that the observed enhancement of phagocytosis was dependent on the binding of fibronectin to Staphylococcus aureus. The ability of fibronectin to opsonize different strains of Staphylococcus aureus varied with the strain. A variation was also observed in fibronectin-induced phagocytosis by leukocytes from different donors.

Blood Bactericidal Activity↗
PubMed1984

Bacterial histamine release by immunological and non-immunological lectin-mediated reactions.

The mechanisms of bacteria-induced histamine release were examined in vitro in human leukocytes and rat mast cells. Three types of bacterial responders were found. In persons with IgE-bearing basophilocytes bacterial histamine release could be triggered by two different mechanisms, an IgE-dependent mechanism where removal of IgE abolished the release and a non-immunological mechanism where this was not the case. In responders with no IgE-bearing cells bacterial histamine release was caused by a non-immunological mechanism. The non-immunological mechanism was further substantiated by release in isolated mast cells from germ-free rats. These experiments suggest a direct interaction between bacteria and target cell, and experiments with multi-washed bacteria and bacteria cell wall preparations indicate the possibility of the bacteria wall interacting with the target cell. It is probable that the non-immunological mechanism depends on lectin-mediated reactions, since bacteria-induced histamine release was inhibited by lectin-binding sugars as is release caused by plant lectins.

Basophils↗
PubMed1984

Complexity of lectin-mediated reactions in bacteria-induced histamine release.

We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations.

Adult↗
PubMed1984

Induction of immunoglobulin secretion in cultured human lymphocytes by 4 Staphylococcus aureus strains and their extracts.

Human blood lymphocytes were stimulated in vitro by four Staphylococcus aureus strains. Activation of immunoglobulin-secreting cells was determined by a reverse plaque forming cell (PFC) assay, and proliferation by quantitation of thymidine incorporation. Whole killed S. aureus were slightly more efficient than water-soluble preparations in the form of sonicated extracts and culture supernatants. Two S. aureus strains rich in protein A (Cowan I and E 2371) and one S. aureus strain deficient in protein A (E 1369) were potent B-lymphocyte stimulators inducing maximal activity on day 6 of culture. Another S. aureus strain deficient in protein A (Wood 46) did not possess++ human lymphocyte stimulating capacity.

Hemolytic Plaque Technique↗
PubMed1984

Secretion rates of immunoglobulins, albumin, haptoglobin and complement factors C3 and C4 in the perfused jejunum and ileum of human Salmonella carriers.

Secretion rates of immunoglobulins and other proteins were assessed by luminal perfusion of jejunum and distal ileum, and the jejunal histology was evaluated in eight Danish chronic Salmonella typhi and paratyphi carriers compared to nine healthy controls who previously had suffered from typhoid or paratyphoid fever not followed by a carrier state. The median secretion rates for each protein investigated in the distal ileum as well as in the jejunum revealed no significant differences between the two groups. The secretion rate of secretory IgA was raised in both groups compared to previously investigated normal persons. The histological examination revealed no signs of inflammation or presence of bacteria. It was concluded that no primary humoral immune defect was revealed in the carriers.

Adult↗