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Biomedical subjects

G Döring

Publications and source records attributed to G Döring.

At least 109 records · Page 6Linked to original sources
PubMed1987

Relevance of host-derived and bacterial factors in Pseudomonas aeruginosa corneal infections.

Two pathogenic mechanisms of Pseudomonas aeruginosa corneal infections are discussed, one involving bacterial exoenzymes, the other involving polymorphonuclear leukocyte (PMN)-derived lysosomal enzymes. The objective of the present study was (1) to show the relative importance of the two mechanisms and (2) to evaluate the effect of active immunization against P. aeruginosa exoenzymes on ocular damage. Rabbits were immunized against P. aeruginosa alkaline protease (AP) or elastase (Ela) and challenged with the respective enzymes. Corneal damage was studied by light photography (LP). In another group, rabbits were immunized against AP, Ela and exotoxin A (ExoA) and challenged with P. aeruginosa strains PA01 or PA103. Corneal damage was studied with LP, light microscopy, and electron microscopy. Immunized animals were totally protected against intracorneal inoculation of P. aeruginosa proteases. Twelve hr and 24 hr after challenge with whole bacteria, immunized rabbits revealed less corneal damage than non-immunized animals. However, after 48 hr corneal damage (ie severe corneal ulceration) was comparable in both groups. The study suggests that corneal damage involving lysosomal enzymes from stimulated PMN is more important after bacterial infection than direct damage by P. aeruginosa exoenzymes.

Animals↗
PubMed1986

[Results of a representative survey of family planning behavior in West Germany 1985].

A report on the result of a representative survey of family planning behavior in the Federal Republic of Germany in 1985. Interviewers from the EMNID Institute questioned 1267 German women aged between 15 and 45. Of the women interviewed, 6.1% had been sterilized, while in 1.3% of cases, their partner had been sterilized. Regarding the use of reversible methods of contraception, the following figures were established: pill, 37.1%; IUD, 10.3%; condom, 5.9%; rhythm method, 3.9%; withdrawal 3.4%; vaginal diaphragm, 2.1%; mini-pill, 1.3%; locally effective chemical substances, 0.8%. A few women (1.9%) stated that they used a mixture of methods. No information about family planning methods was offered by 13.4% of the women interviewed. The figures obtained were further differentiated according to age, marital status, school education, religion, number of children, desire for more children, profession, and net income. The authors' own questions concerned the early use of contraceptives, the reasons for abandoning a particular method, the reasons for choosing a certain type of contraceptive, sources of information about family planning, the frequency of changes from one type of contraceptive to another, and opinions about the rhythm method. Finally, the result of the EMNID survey is compared with that of known studies both at home and abroad.

Adolescent↗
PubMed1986

Demonstration of neutrophil chemotactic activity in the sputum of cystic fibrosis patients with Pseudomonas aeruginosa infection.

The pathogenesis of tissue damage in the lungs of cystic fibrosis patients with chronic P. aeruginosa infection is quite complex and not well understood. Inflammatory cells, particularly neutrophils, are accumulated in the damaged tissues and in the sputum. This study demonstrates the presence of a heat-stable neutrophil chemotactic factor(s) in the sputum of CF patients. The chemotactic activity seems to be associated with the endotoxin present in the sputum. Chemotaxis of sol phase sputum was determined in a modified Boyden chamber assay. It was found that the sputum obtained from the patients showed strong chemotactic activity for peripheral blood neutrophils of normal individuals. The activity was greater than twice that of casein, a strong neutrophil chemo-attractant. Sputum at about dilution of 1:50 exhibited chemotactic activity equal to that of casein. Heat treatment of the sputum at 56 degrees C for 30 min, to inactivate complement, and at 100 degrees C for 15 min, to denature other proteins, somewhat reduced the chemotactic activity, but there was still strong chemotactic activity. The presence of endotoxin was demonstrated in both the non-heated and the heated samples by LAL and rocket immunoelectrophoresis. It is concluded that the sputum of CF patients contain chemotactic activity of heat-stable nature and most likely of bacterial origin endotoxin. These factors are involved in attraction of neutrophils to the lungs and sputum of these patients and contribute to the tissue damage of cystic fibrosis.

Chemotaxis, Leukocyte↗
PubMed1986

Effect of Pseudomonas aeruginosa proteases on human leukocyte phagocytosis and bactericidal activity.

The effect of Pseudomonas aeruginosa alkaline protease (AP) and elastase (Ela) on neutrophil phagocytosis and bactericidal activity was examined. It was found that both proteases reduced the phagocytic activity of the leukocytes against P. aeruginosa, whereas they had little effect on the phagocytosis of S. aureus. AP and Ela at concentration of up to 250 micrograms per ml (much higher than the levels detectable under in vivo conditions) did not interfere with the bactericidal activity of the leukocytes against both test organisms. Inhibition of phagocytosis by AP and Ela without effect on the bactericidal activity suggests that the P. aeruginosa proteases most probably exert their effect on the cell surface perhaps by proteolytic cleavage of the cell receptors which are necessary for phagocytosis.

Blood Bactericidal Activity↗
PubMed1986

Lysosomal enzymes from polymorphonuclear leukocytes and proteinase inhibitors in patients with cystic fibrosis.

In serum and sputum samples from 15 patients with cystic fibrosis (CF) suffering from chronic Pseudomonas aeruginosa lung infections, concentrations and/or activities of elastase derived from polymorphonuclear leukocytes (PMN), cathepsin G, myeloperoxidase (MPO), and superoxide dismutase (SOD), as well as concentrations of the proteinase inhibitors alpha 1-proteinase inhibitor (alpha 1-PI) and alpha 2-macroglobulin (alpha 2-M), were determined. High enzyme concentrations compared with those in normal control subjects were found for PMN elastase (mean, 96.1 +/- 91.7 micrograms/ml), cathepsin G (mean, 5.9 +/- 6.0 micrograms/ml), and MPO (mean, 138.0 +/- 177 micrograms/ml) in patients' sputum samples. Superoxide dismutase was not detectable in any of the sputum specimens (below 1 ng/ml). Proteinase inhibitor concentrations were elevated in serum samples (alpha 1-PI: mean, 3,457 +/- 1,084 micrograms/ml; alpha 2-M: mean, 4,835 +/- 1,334 micrograms/ml). Means of 61 +/- 38 micrograms/ml alpha 1-PI and 29 +/- 31 micrograms/ml alpha 2-M were present in the sputum specimens. Both proteinase inhibitors were functional in the serum samples. However, sputum alpha 1-PI was proteolytically degraded, as shown by western blot technique, and was not able to bind 125I-labeled PMN elastase, as shown by autoradiography. Only 10.9 +/- 8.5% of the total alpha 1-PI in the sputum samples was complexed to PMN elastase and 3.6 +/- 3.2% to cathepsin G. On the other hand, 96.2 +/- 96.8% of the total PMN elastase and 78.0 +/- 100% of cathepsin G were unbound in the sputum samples. The study suggests that the imbalance between PMN proteinases and their inhibitors is due to inactivation of alpha 1-PI in the sputum caused by proteolytic or oxidative attack from PMN enzymes.

Blood Proteins↗
PubMed1986

Elastase from polymorphonuclear leucocytes: a regulatory enzyme in immune complex disease.

In sputa of 21 cystic fibrosis patients suffering from chronic Pseudomonas aeruginosa lung infections, activities of lysosomal proteases released from polymorphonuclear leukocytes (PMN) and immune complexes were quantitatively determined. The results showed that low immune complex values correlated with high protease activities and vice versa. In a longitudinal study fluctuating, reciprocal changes of the parameters were observed. Therefore, the hypothesis was investigated as to whether PMN elastase cleaves immune complexes and regulates inflammation. It was shown that treatment of immune complex-positive sputa with PMN elastase decreased IgG and IgA immune complex values and lead to cleavage of the immunoglobulins in the hinge region. PMN elastase-treated samples were not able to stimulate the oxidative burst of PMN. Cleavage of in vitro built immune complexes did not lead to liberation of bound antigen. Western blot analysis of one sputum sample revealed split products of the IgG heavy chain. The results suggest that PMN elastase splits off the Fc portion of immunoglobulins in immune complexes and thus regulates inflammation by a feedback mechanism leading to cyclic inflammatory states.

Antigen-Antibody Complex↗
PubMed1985

Role of Pseudomonas aeruginosa exoenzymes in lung infections of patients with cystic fibrosis.

We investigated the role of Pseudomonas aeruginosa exoenzymes in cystic fibrosis lung infection in the presence and absence of specific serum antibodies. In sputa of 21 cystic fibrosis patients, concentrations of P. aeruginosa proteases and exotoxin A were determined by sensitive radioimmunoassays. In all sputa, detection of exoenzymes was negative (less than or equal to 10 ng). Positive serum antibody titers to bacterial exoenzymes were found in the majority of patients. Purified immunoglobulin G (IgG) preparations from the sera of two patients revealing specific antibody titers to the bacterial proteases neutralized these enzymes at ratios of 1,000:1 to 5,600:1 (wt/wt). Above the neutralizing capacity of IgG, proteases caused cleavage of IgG; below that level, no enzymatic activity was observed. In vitro incubation of P. aeruginosa elastase, alkaline protease, or exotoxin A with elastase derived from polymorphonuclear leukocytes showed that polymorphonuclear leukocyte elastase: (i) was cleaved by bacterial elastase, (ii) was not inactivated by alkaline protease, and (iii) inactivated exotoxin A. The results suggest that soon after the onset of P. aeruginosa lung infection in cystic fibrosis patients, bacterial proteases, but not exotoxin A, become important virulence factors. The results also suggest that exoenzymes do not directly contribute to lung damage after immune response to bacterial antigens has begun.

Cystic Fibrosis↗
PubMed1985

[Pseudomonas aeruginosa in the oral cavity: occurrence and age distribution of adult germ carriers].

Among 500 patients of a rural general practice, 4,4% proved to be oropharyngeal carriers of Pseudomonas aeruginosa as shown by examination of mouth rinse fluid through enrichment in malachite-green-broth followed by isolation on Pseudosel-Agar at 42 degrees C. Most positive samples were found in persons 54-63 years old. There were no significant sex differences. The isolation of Ps. aeruginosa showed no relation to visible inflammatory processes in the oral cavity, to dentures, diabetes mellitus, chronic respiratory disease, former antibiotic treatment or smoking habits. The age distribution of the carriers cannot be explained.

Adult↗
PubMed1984

In vivo activity of proteases of Pseudomonas aeruginosa in a rat model.

The granuloma pouch technique was used to study the in vivo characteristics of four strains of Pseudomonas aeruginosa that differed in levels of alkaline protease and elastase production. Bacterial counts, alkaline protease and elastase concentrations, and IgG levels of pouch exudates were determined quantitatively; total protein levels were determined semiquantitatively. In vivo protease concentrations were in the nanogram range; during the investigated period individual strains either increased enzyme production or remained negative. In vitro alkaline protease:elastase ratios correlated with in vivo ratios in three of the four strains. Proteolytic strains caused a decrease in IgG and alpha 2-fraction proteins. Purified rat IgG was cleaved rapidly by elastase and slowly by alkaline protease; both cleaved IgG at the hinge region. The study determines the concentration of P aeruginosa alkaline protease and elastase after infection in a rat model, shows cleavage of rat IgG and other proteins due to alkaline protease and elastase, and suggests that enzymes other than proteases are involved in the pathogenesis of P aeruginosa infections.

Animals↗
PubMed1984

Detection of proteases of Pseudomonas aeruginosa in immune complexes isolated from sputum of cystic fibrosis patients.

Sera and sputa of 12 cystic fibrosis patients suffering from chronic Pseudomonas aeruginosa lung infections were assayed for immune complexes using the Raji cell assay. Whereas all sera were negative, 33% of the sputa were positive for immune complexes. Sera and sputa of these patients were also assayed for antibodies against P.aeruginosa alkaline protease (AP) and elastase (Ela) and sputa for AP and Ela, using radioimmunoassays. All patients revealed antibody titers to the proteases in serum (1:5-1:1000) and eight patients had antibody titers to the proteases in sputum (1:5-1:100); all sputa were negative for AP and Ela. Sputum immune complexes and IgG were separated from whole sputum on a Protein A-Sepharose C1-4B column and treated with 0.75 M 2-mercaptoethanol and iodoacetamide after elution. After treatment, 58% of the sputa were positive for AP and/or Ela (5-200 ng/ml sputum). The present study shows that proteases of P.aeruginosa are bound in immune complexes after the initiation of the immune response to these antigens and it yields new insights into the role of these proteases in chronic lung infection in cystic fibrosis.

Antigen-Antibody Complex↗
PubMed1984

Interaction of Pseudomonas aeruginosa alkaline protease and elastase with human polymorphonuclear leukocytes in vitro.

Little is known about the interaction of Pseudomonas aeruginosa extracellular products and human polymorphonuclear leukocytes. The present study was designed to examine the effect of alkaline protease and elastase purified from P. aeruginosa on human neutrophil function. Neutrophil chemotaxis, oxygen consumption, glucose oxidation, superoxide production, and nitro blue tetrazolium reduction were studied. It was found that alkaline protease and elastase at fairly low concentrations (0.05 and 0.0025 micrograms/ml, respectively) inhibited chemotaxis. The inhibitory effect of both enzymes was increased at higher concentrations. The chemotaxis of preincubated and washed cells was also inhibited. Alkaline protease but not elastase inhibited opsonized zymosan-stimulated neutrophil oxygen consumption, whereas neither of the enzymes had any effect on glucose oxidation and nitro blue tetrazolium-reducing activity of stimulated neutrophils. The data on superoxide production ability of the cells indicated that the cells preincubated with enzyme and washed were capable of producing superoxide equal to the amount produced by untreated cells when they were stimulated with phorbol myristate acetate or zymosan. However, when elastase was present in the reaction mixture, the reduction of cytochrome c as a measure of superoxide production was inhibited. Inhibition of neutrophil function, particularly chemotaxis, will have important bearing on the escape of the microorganism from the phagocytic defense system of the host. The role of these products in localized infections and avascular areas such as skin burns, cornea, and, at least initially, in chronic lung colonization in cystic fibrosis patients becomes important.

Chemotaxis, Leukocyte↗
PubMed1984

Pseudomonas aeruginosa exoproteases inhibit human neutrophil chemiluminescence.

The present study was designed to examine the effect of Pseudomonas aeruginosa alkaline protease and elastase on human polymorphonuclear leukocyte chemiluminescence. Both a luminol-enhanced and a nonenhanced chemiluminescence system using opsonized zymosan were utilized. It was found that alkaline protease and elastase at concentrations of 25 micrograms/ml strongly inhibited luminol-enhanced myeloperoxidase-mediated chemiluminescence, whereas inhibition of the nonenhanced chemiluminescence response was about 50%. In an attempt to determine the mechanism of inhibition of neutrophil chemiluminescence by these proteases, we examined the effect of various inhibitors of neutrophil oxidative metabolism on chemiluminescence, namely, superoxide dismutase, sodium azide, and catalase. It was shown that the pattern of inhibition of chemiluminescence by alkaline protease and elastase was similar to that of sodium azide, inhibitor of myeloperoxidase. The present study demonstrates that alkaline protease and elastase, extracellular products of P. aeruginosa, are capable of inhibiting myeloperoxidase-mediated chemiluminescence, one of the major antimicrobial systems of polymorphonuclear leukocytes. These findings provide further evidence for the role of P. aeruginosa exoproteases as virulence factors in the pathogenesis of infections caused by this microorganism.

Azides↗
PubMed1983

Proteases of Pseudomonas aeruginosa in patients with cystic fibrosis.

Radioimmunoassays were used to determine titers of antibody to alkaline protease (AP) and elastase (Ela) produced by Pseudomonas aeruginosa in sera and bronchial secretions, in vitro production of AP and Ela by P. aeruginosa isolates, and occurrence of these enzymes in bronchial secretions from patients with cystic fibrosis. Titers of serum antibodies to AP ranging from 1:10 to 1:545 and to Ela ranging from 1:10 to 1:725 were found in 83%-88% of patients with cystic fibrosis and chronic lung infections due to P. aeruginosa. Antibody titers in liquified bronchial secretions were approximately 10% of the serum titers. Thirty-one (93%) of 34 isolates produced both proteases in vitro in comparable amounts (concentration of protease in culture supernatant: AP, 0.01-480 micrograms/ml; Ela, 0.02-490 micrograms/ml). AP and Ela were detected in vivo when antibodies to the enzymes were absent. The results suggest that specific immune responses in patients with cystic fibrosis neutralize proteases of P. aeruginosa.

Adolescent↗
PubMed1983

Longitudinal study of immune response to Pseudomonas aeruginosa antigens in cystic fibrosis.

During a 10-year period, the clinical states of 10 cystic fibrosis patients were evaluated on the basis of monthly measurement of lung function and weight; serum antibody titers to alkaline protease and elastase and the number of precipitins to Pseudomonas aeruginosa standard antigen were determined by radioimmunoassay and crossed immunoelectrophoresis. Alkaline protease and elastase concentrations of the P. aeruginosa strains from the patients were measured in vitro. The immune response increased in nearly all patients after the onset of chronic P. aeruginosa lung infection over years, suggesting unimpaired production of these antigens during P. aeruginosa lung infection, whereas the clinical states declined. The mean time for immune response was 15 months for alkaline protease, 11 months for elastase, and 6 months for standard antigen.

Adolescent↗
PubMed1982

[Heart transplantation: successful treatment of postoperative complications. Case report with 19 months' follow-up].

In March, 1981, a 37-year old patient underwent cardiac transplantation, the first to be performed in Germany since 1969. Subsequent to the successful procedure, the patient has now been followed for more than 19 months. The indication for the intervention was established on the basis of endstage coronary artery disease. The operation was performed according to the technique of Lower and Shumway. Immunosuppression, in the early postoperative phase, was carried out with antithymocyte globulin, azathioprine and corticosteroids with administration oriented on the T-lymphocyte and total leukocyte counts as well as analysis of myocardial biopsies. In the late postoperative course, dosage of immunosuppressive agents was based almost exclusively on biopsy findings. Within the course of immunosuppressive therapy for cardiac transplantation, in particular, initial experience was gained with the use of antithymocyte globulin which was given in dosages of up to 12 mg/kg daily. The antithymocyte globulin proved effective for more than six weeks postoperatively. The alterations in immunosuppressive treatment necessitated by two gastrointestinal complications (perforated gastric ulcer, perforation of the small intestine) enabled a comparative analysis of the results of therapy with cyclosporin A given orally, intravascularly and intravenously. The Patient continues to be maintained on a regimen of cyclosporin A and corticosteroids and his general condition is good. For future cardiac transplantations, in the early postoperative course, alternating treatment with antithymocyte globulin, azathioprine and corticosteroids, on the one hand, with cyclosporin A and corticosteroids, on the other hand, would seem meaningful both to minimize adverse reactions as well as to provide effective immunosuppression. The experience rendered would promise to facilitate management of patients after cardiac transplantation.

Adolescent↗
PubMed1982

Extracellular toxins of Pseudomonas aeruginosa. III. Radioimmunoassay for detection of alkaline protease.

A sensitive and specific solid phase radioimmunoassay (RIA) for detection of the alkaline protease (AP) of Pseudomonas aeruginosa (PA) was developed and the RIA was used to assay 10 PA strains of various origin and serotype. A great strain variability of AP production was found which differed from 180 to 0.1 microgram per ml of culture supernatant fluid (CSF). The AP concentrations were compared to the total proteolytic activity of the CSF and the results were discussed in relation to cystic fibrosis patients suffering from chronical PA lung infections.

Hydrogen-Ion Concentration↗
PubMed1982

Extracellular toxins of Pseudomonas aeruginosa. IV. Radioimmunoassay for detection of elastase.

A sensitive and specific solid phase radioimmunoassay (RIA) for detection of the elastase (Ela) of Pseudomonas aeruginosa (PA) was developed and the RIA was used to assay 10 PA strains of various origin and serotype. A great strain variability of Ela production was found which differed from 94.1 to 0.1 microgram per ml of culture supernatant fluid (CSF). The Ela and alkaline protease (AP) concentrations were converted to proteolytic activity and combined. The sum of the calculated enzymatic values of Ela and AP correlated well with the experimentally determined values of total proteolytic activity of the CSF.

Pancreatic Elastase↗