Biomedical subjects

W Rudnicka

Publications and source records attributed to W Rudnicka.

At least 37 records · Page 2Linked to original sources

PubMed1998

Systemic humoral response to Helicobacter pylori in children and adults.

In this study we compared the development of anti-H. pylori humoral response in adults and children. Two antigens: H. pylori acid glycine extract (GE) and recombinant cagA were used for ELISA and Western blot. Anti-GE IgG were detected in all and anti-cagA IgG in about 50% of H. pylori infected adults and children. The prevalence of anti-GE and anti-cagA IgG in the sera from H. pylori-uninfected children with gastritis/gastroduodenitis was lower than in the sera from healthy adult blood donors. Serum IgA were demonstrated for 71% of H. pylori-infected adults and for a smaller proportion (about 30%) of uninfected adult patients or normal subjects. Such antibodies were detected neither for infected nor for uninfected children. There was an evident difference between the proteins of H. pylori glycine extract recognized by antibodies present in the sera from H. pylori-infected children and adults. The antigen of molecular weight over 107 kDa was recognized exclusively by the sera from 30% of H. pylori-infected adults. The 80-107 kDa bands were recognized more frequently by the sera from adults than from children. In contrast, sera from infected children more frequently than sera from infected adults reacted with the bands of 14 kDa, 19 kDa and 26 kDa. The H. pylori antigens recognized by IgG, produced by infected children and adult patients, should be taken into consideration in the developing of tests for serodiagnosis of H. pylori infection.

Adolescent↗

PubMed1998

The virulence of Staphylococcus aureus isolates differing by siderophore production.

In previous study we demonstrated that Staphylococci aureus clinical and environmental isolates differ by siderophore production (Lisiecki et al., 1997), the aim of the present study was to check a possible role of siderophore-dependent iron acquisition system of outcome of staphylococcal diseases. The systemic and local staphylococcal infections were induced in mice by inoculation of three S. aureus strains differing by siderophore production. We found that S. aureus B 47 strain characterized by enhanced siderophore activity was more virulent in both systemic and local infection models and it was more resistant to anti-bacterial activity of neutrophils than S. aureus B 63 and B 32 strains expressing weaker siderophore production. The results suggest that effective siderophore-dependent iron acquisition system may be beneficial to S. aureus strains in their pathogenic activity in vivo.

Animals↗

PubMed1998

[Detection of bacterial biofilm on medical biomaterials].

This study was performed to assess the value TTC assay in the diagnosis of biomaterial-associated infections. In this assay, soluble colourless TTC is reduced to insoluble red formazan by electron transfer associated with active oxidative bacterial metabolism and is precipitated intracellularly. Microbial adhesion and biofilm formation on the surface of medical prosthetic devices (vesicular and urinary catheters) made of various polymers (PTFE, H-PE, PCW, SL), were determined. The microorganisms which are most often isolated in medical device-associated infections: S. aureus, S. epidermidis, E. faecalis, E. coli, P. vulgaris, P. aeruginosa, C. albicans, were included into the study. The obtained results indicate that the assay using TTC as a metabolic indicator of bacterial biofilm presence, is technically simple to conduct with minimal setup time. Even when classical cultures yielded no bacterial growth, TTC assessments demonstrated bacterial biofilms. TTC assay could be recommended as a quick routine method for confirmation of biomaterial device-associated infection.

Animals↗

PubMed1997

The immune response to staphylococcal antigens in mice depleted of macrophages by Cl2MDP-liposomes.

To investigate the role of macrophages in the induction of the production of antibody to staphylococcal antigens, we used Cl2MDP (clodronate) liposomes as a tool for local macrophage depletion. Macrophage depletion caused in mice by intraperitoneal (i.p.) injection of Cl2MDP liposomes was associated with a reduction in the clearance of Staphylococcus aureus Cowan 1 bacteria from the tissues of infected animals and with a marked decrease in the bactericidal activity of macrophages escaping from the lethal effect of clodronate. Despite the functional defect of macrophages, the mice treated with Cl2MDP liposomes two days before the injection of alpha-toxin (toxoid) or whole heat-killed S. aureus Cowan 1 bacteria, demonstrated an enhancement in the production of anti-staphylococcal alpha-toxin IgM and anti-collagen-binding protein IgG. A similar enhancement of antistaphylococcal antibody synthesis was observed in mice after receiving phosphate buffered saline (PBS) encapsulated in liposomes.

Animals↗

PubMed1997

Listeria monocytogenes infection in mice treated with pentoxifylline.

The course of L. monocytogenes infection was followed in mice treated with pentoxifylline (POF), a known inhibitor of endogenous tumor necrosis factor (TNF) formation. Administration of POF caused a delay in L. monocytogenes elimination which was probably related to a reduction the listericidal activity of macrophages and to an attenuation of delayed type hypersensitivity (DTH) to Listeria antigens. In spite of this, some POF-treated mice were protected from lethal effects of virulent L. monocytogenes bacteria.

Animals↗

PubMed1997

Serological indicators of Helicobacter pylori infection in adult dyspeptic patients and healthy blood donors.

The levels of IgM, IgG and IgA antibodies reacting with two Helicobacter pylori antigens (glycine acid extract (GE) and a recombinant CagA protein) were determined in the sera from adult dyspeptic patients, positive (H.p.(+)) or negative (H.p.(-)) for H. pylori urease/culture, and from healthy blood donors. All sera were also examined against GE by Western blot (Immunoblot) technique. Similar levels of anti-GE IgG were detected in the sera from all H.p.(+) and almost all H.p.(-) patients and from over 40% of the healthy volunteers. In contrast, higher levels of anti-GE IgA were found in the sera from patients than that from healthy subjects, although such antibodies were not detected in the sera from 30% of the H.p.(+) patients. In general, our results suggest that a combination of ELISA and immunoblot may be more sensitive in the detection of H. pylori infection in dyspeptic patients than the examination of biopsy specimens by culturing or histology.

Adult↗

PubMed1997

The host response to Listeria monocytogenes mutants defective in genes encoding phospholipases C (plcA, plcB) and actin assembly (actA).

Several genes involved in the determination of Listeria monocytogenes pathogenesis have been identified. Among them, plcA gene encodes phosphatidylinositol-specific phospholipase C (PI-PLC), plcB gene encodes a broad-range phospholipase C (PC-PLC), and actA encodes a protein contributing to actin assembly in infected cells. The interaction of L. monocytogenes wild type (LO 28) strain and two derivative mutants, plcA- (BUG 206) and actA-/plcB- (LUT 12), with macrophages and T lymphocytes was investigated in a mouse model of listeriosis. Both mutants showed evidence of attenuation. The plcA- mutant, but not the plcB- mutant, expressed an increase in susceptibility to the anti-listerial activity of macrophages. Both mutants showed a decreased ability to induce IL-12 production by bone marrow macrophages when co-stimulated with E. coli LPS or IFN-gamma. In vivo, L. monocytogenes plcA- mutant was found to be a more effective stimulator of T cells than the wild LO 28 strain.

Actins↗

PubMed1997

Specific immune response to staphylococcal antigens during long-lasting biomaterial implantation.

Biomaterial-associated infections caused by staphylococci are one of the main therapeutic problems in modern medicine. There is no doubt that local disfunction of polymorphonuclear leukocytes and macrophages predisposes to such infections. However, it is not clear how implantation of a foreign body influences the antibacterial immune response. We analyzed some parameters of the specific immune response to staphylococcal antigens, in mice implanted for 3 months with heparinized polyethylene. Three weeks before the evaluation of the immune response, mice (implanted and non-implanted) were infected i.p. with 2 x 10(7) cells of Staphylococcus aureus Cowan 1. The proliferation of splenocytes was determined on the basis of [3H]thymidine incorporation in cultures stimulated with staphylococcal lipoteichoic acid, protein A, alpha-toxin, or phytohemagglutinin. Moreover, the level of specific antibodies to staphylococcal antigens was determined in serum samples (ELISA with the antigens lipoteichoic acid, protein A, and alpha-toxin). The data obtained indicate that long-lasting implantation caused evident changes in proliferative activity of lymphocytes and in humoral response to staphylococcal antigens. It enhanced spontaneous and lipoteichoic acid- or alpha-toxin-stimulated proliferation of splenocytes, in vitro. In contrast, heparinized polyethylene-implanted animals showed a significant decrease in the production of anti-protein A IgG2b and anti-alpha-toxin IgG2a and IgG2b.

Animals↗

PubMed1997

Role of Helicobacter pylori surface structures in bacterial interaction with macrophages.

BACKGROUND: Helicobacter pylori infection is associated with a marked infiltration of the gastric epithelium by neutrophils, macrophages, lymphocytes, and plasma cells. Despite the presence of phagocytes in close vicinty to H pylori microbes a great number of people are unable to eradicate bacteria. AIMS: To investigate the involvement of multiple bacterial 'adhesins' and some phagocytic receptors in the process of the ingestion of H pylori by macrophages. BACTERIA: H pylori strains differing in the expression of sialic acid dependent (sHA) or sialic acid independent (HA) haemagglutinin and heparan sulphate binding were selected for the study. METHODS: The uptake of fluorescein labelled H pylori bacteria by a homogenous macrophage cell line J 774A.1 was estimated in a quantitative fluorometric assay. RESULTS: The ingestion of H pylori 17874 and 25 strains expressing sHA was inhibited by the pretreatment of the bacteria with anti-sHA antibodies or fetuin as well as by treatment of the macrophages with neuraminidase. In contrast the uptake of H pylori 17875 strain expressing HA remained unchanged. The phagocytosis of all investigated bacteria was inhibited after the treatment with heparin, hyaluronic acid or vitronectin with fresh but not heat inactivated serum. CONCLUSIONS: The results suggest that H pylori surface compounds binding host proteins such as fetuin, heparin/haparan sulphate, hyaluronic acid, and vitronectin in the presence of complement, could allow the bacteria to avoid phagocytosis.

Adhesins, Bacterial↗

PubMed1997

[Immunologic reactions in infections caused by Helicobacter pylori].

Helicobacter pylori is recognized as an important cause of chronic antral gastritis and peptic ulceration. Moreover, H. pylori associated inflammatory process has been linked with gastric carcinoma. Many putative virulence factors of H. pylori have been suggested, including motility, urease and cytotoxins production and bacterial adhesins. An accessory function of CagA antigen and bacterial heat-shock proteins in the pathogenesis of H. pylori infections have been also considered. H. pylori-induced immunological response is discussed as regards local and general antibody production, the interaction of the bacteria with the phagocytes and still controversial involvement of T cells. Data on the importance of cytokines and inflammatory mediators in the disruption of the gastric mucosal barriers as well as the evidence to support a role for H. pylori as a risk factor for gastric carcinoma are also presented.

Antibody Formation↗

PubMed1997

Attachment of Helicobacter pylori strains to human epithelial cells.

The aim of the study was to characterize several clinical isolates of H. pylori as regards the activity and specificity of their haemagglutinins and the involvement of surface sialic acid-specific and heparin-binding compounds in the adhesin of the bacteria to human epithelial cell lines. Although H. pylori strains caused haemagglutination (HA) of sheep erythrocytes, they differed markedly by activity and specificity. On the basis of haemagglutination inhibition study three types of H. pylori strains could be distinguished. The HA of Type I strains was inhibited with fetuin/mucin but not asialofetuin/asialomucin. The HA activity of Type II strains was inhibited with fetuin/mucin and asialofetuin/asialomucin. The HA of Type III strains was not influenced by any of these inhibitors. In vitro, H. pylori strains bound to the cells of human epithelial lines: HeLa, Kato-3, Ags. However, various compounds mediated the binding of H. pylori types distinguished by HA, to epithelial cells. The interaction of some of H. pylori strains with epithelial cells was mediated by bacterial sialic acid-binding compounds. The majority of H. pylori strains used heparin-binding surface compounds to attach to epithelial cells. Clinical H. pylori strains differ by the compounds used in adhesin to epithelial cell lines, however, this process also depends on the expression of appropriate receptors on the host cells.

Bacterial Adhesion↗

PubMed1997

Altered immune response to staphylococcal antigens in long-lasting implanted mice.

Staphylococcal infections constitute one of the main problems associated with clinical applications of various prosthetic medical devices (biomaterials). As the magnitude of the infection risk depends often on the duration of device installation, and the incidence of infections is higher in skin-penetrating devices, we studied some parameters of specific immune response to staphylococcal antigens in mice subcutaneously (s.c.) implanted for three months with heparinized polyethylene (H-PE). Three weeks before the evaluation of immune response, mice (implanted and non-implanted) were s.c. infected with 10(7) of Staphylococcus aureus Cowan 1. The proliferation of lymph node cells was determined on the basis of 3H-thymidine incorporation in 3-days cultures stimulated with: staphylococcal lipoteichoic acid (LTA), protein A (SpA), alpha-toxin, or with phytohemagglutinin (PHA). Moreover, the levels of specific antibodies to staphylococcal antigens were determined in serum samples (ELISA against: LTA, SpA, alpha-toxin). The data obtained indicate that long-lasting implantation caused evident changes in proliferative activity of lymphocytes and humoral response to staphylococcal antigens. It enhances alpha-toxin and LTA stimulated proliferation of lymph node lymphocytes in vitro. In contrast, H-PE-implanted animals demonstrated a significant decrease in the production of anti-SpA IgG2a and IgG2b and increase in the synthesis of anti-LTA IgG1 antibodies.

Animals↗

PubMed1997

Haemolytic activity of Mycobacterium spp.

Haemolytic activity of clinical isolates of Mycobacterium bacilli (98) was determined by the method of King et al., 1993. During 3-h incubation, all M. tuberculosis (MTB) isolates (28) and one out of 38 M. avium-intracellulare (MAI) strains, produced a strong contact-dependent haemolysin (CDH). Six MAI strains expressed a weak CDH. One MAI isolate produced a strong and five other MAI strains a weak contact-independent haemolysin (CIH). Two M. bovis BCG strains and 7 M. vaccae strains did not demonstrate haemolytic activity. The persistence of chosen Mycobacterium strains differing by haemolytic activity, in the spleens of infected C57BL/6 mice was examined. Mycobacteria producing a strong CDH (MTB H37Rv, MTB 101/92, MAI 83/93) or CIH (MAI 475/93) survived in the spleens of nonimmunized or M. bovis BCG-immunized mice for longer time than MAI strains expressing weak haemolytic activity or M. bovis BCG vaccine strain.

Animals↗

PubMed1996

The cells of monocyte-macrophage lineage in mice with the 2-month polyethylene implantation.

End-point-attached heparinized polyethylene (H-PE) was implanted for 2 months into the peritoneum of C57B1/6 mice. The proliferation of bone marrow cells (BMCs) from implanted and non-implanted mice was investigated in M-CSF supplemented medium, in the presence or absence of macrophage-specific monoclonal antibodies (mAbs). The mAb HC 7.67.B, recognizing a surface determinant on immature monocytoid cells, inhibited the proliferation of BMCs from H-PE implanted mice without any influence on the proliferation of BMCs from non-implanted animals. The peritoneal macrophages from H-PE implanted mice demonstrated enhanced production of fibronectin (Fn) in comparison to the macrophages from non-implanted animals. Our results suggest changes in the differentiation of murine monocyte-macrophage lineage in the mice bearing H-PE implants for 2 months.

Animals↗

PubMed1996

The proliferation of human T lymphocytes stimulated by Helicobacter pylori antigens.

Fractionated mononuclear cells (MNCs) were obtained from peripheral blood of healthy human volunteers, seronegative for H. pylori antibodies. The MNCs were stimulated in culture with whole live or heat-killed H. pylori cells or with bacterial cell surface (SA) or cytoplasmic (CA) antigens. There was a marked proliferative response of T cells in cultures stimulated with 10(5) cells/well of live H. pylori, 5 micrograms/well of CA or 5-20 micrograms/well of SA. However, no proliferation was observed in MNC cultures containing higher "doses" of live H. pylori organisms (10(7)/well) or CA (20 micrograms/well). Moreover, higher "doses" of the bacteria or CA entirely inhibited the response of T cells to PHA.

Adhesins, Bacterial↗

PubMed1996

Phagocytosis of Helicobacter pylori bacteria differing in the heparan sulfate binding by human polymorphonuclear leukocytes.

Heparan sulfate binding proteins (HSBPs) of Helicobacter pylori facilitate bacterial phagocytosis by human polymorphonuclear leukocytes (PMNs). H. pylori 25 strain which demonstrates a strong heparan sulfate binding activity was found to be attached to/ingested by PMNs in greater numbers than H. pylori strain 17874 bacteria which lacked this activity. Moreover, heparin inhibited the uptake of cells of H. pylori strain 25 but not of cells of H. pylori strain 17874 by PMNs.

Bacterial Adhesion↗

PubMed1996

Effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on biomaterial-associated staphylococcal infection in mice.

Staphylococcal infections are a major complication in the usage of biomaterials. Different modifications of polymers have been made to reduce the incidence of such infections. We studied the effects of modifying heparinized polyethylene (H-PE) with mouse recombinant granulocyte-macrophage stimulating factor (rGM-CSF). The elimination of staphylococci (Staphylococcus aureus, S. epidermidis) from the peritoneum of mice implanted with rGM-CSF-coated H-PE was slightly more effective than the elimination of the bacteria from the peritoneum of animals implanted with uncoated H-PE. Most interestingly, the number of staphylococci present in the biofilms covering rGM-CSF-coated implants were significantly lower than the number of bacteria detected on the surface of H-PE not coated with rGM-CSF. In vitro, rGM-CSF restored the anti-bacterial potency of the phagocytes, which had been reduced by surface contact with H-PE. The results suggest that modification of biomaterials with rGM-CSF could be one way of preventing staphylococcal infections; especially in neutropenic disorders, which constitute the highest risk factor for foreign body-associated infections.

Animals↗

PubMed1996

The stimulation and inhibition of T cell proliferation by Helicobacter pylori components.

The purified T cells from peripheral blood of healthy human volunteers, seronegative for anti-Helicobacter pylori antibody were stimulated in cultures with live or heat-killed H. pylori rods or with bacterial sialic acid-specific surface haemagglutinin (sHA), a crude surface (SF) or cytoplasmic (CF) fractions. It is demonstrated that H. pylori bacteria contain both stimulatory and inhibitory components for T cells of healthy individuals. The sHA as well as SF (5-20 micrograms) induced the proliferative response of T lymphocytes. By contrast, CF inhibited in dose dependent manner, the proliferation of T cells in the cultures stimulated with H. pylori bacteria or PHA. The result suggest that in vivo, a dominance of activation or immunosuppression could depend on the concentration of the bacteria and their products in infective foci.

Adult↗