Biomedical subjects

W Rudnicka

Publications and source records attributed to W Rudnicka.

At least 19 recordsLinked to original sources

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

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↗

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↗

PubMed1995

Biomaterial-associated infection with Candida albicans in mice.

Candida yeasts are frequently isolated from patients with continuous ambulatory peritoneal dialysis peritonitis or other biomaterial-associated infections. The mouse model of candidal peritonitis was used to study the interaction of Candida cells with end-point attached heparinized polyethylene (H-PE) and with polymorphonuclear leukocytes (PMNs) or macrophages (M phi). Two Candida strains differing in cell surface hydrophobicity and in expression of fibronectin (Fn) binding were used for the study. Cells of both Candida strains adhered at higher numbers to H-PE surfaces preadsorbed with Fn or with human dialysis fluid (HDF) than to non-modified H-PE, supporting a role of Fn in mediating adhesion. C. albicans 4016 cells expressing low hydrophobicity and low binding of soluble Fn demonstrated stronger adhesion to PMNs than the more hydrophobic C. albicans 3248 yeasts, which express high binding of soluble Fn. However, C. albicans 4016 cells were more resistant to phagocytic killing and were hardly eradicated in intraperitoneally infected mice. The animals depleted in PMNs by treatment with CY were neither able to eradicate C. albicans 3248 (rapidly eliminated by normal mice) nor C. albicans 4016 yeasts (with a tendency to persist in the tissues of normal mice).

Animals↗

PubMed1995

Listeria monocytogenes infection in pregnant mice: abnormalities in the function of non-adherent accessory light density dendritic cells.

Pregnant A/J mice were found to be more susceptible to the lethal effect of Listeria monocytogenes bacteria than virgin females. However, during the first four days of post-infection there was no difference in the elimination of Listeria from the spleens of pregnant and virgin mice. This suggests that the increase in the susceptibility of pregnant mice to pathogenic activity of L. monocytogenes was related to the diminution in Listeria-specific cellular reactions. Indeed, we found that non-adherent light density dendritic cells (DCs) from pregnant mice showed a marked reduction in the ability to form clusters with L. monocytogenes immune T lymphocytes and it is known that cell cluster formation between antigen presenting cells (APC) and responding T cells is required for antigen recognition as well as for cell proliferation. DCs from pregnant mice also demonstrated the decrease and an instability in the expression of H-2 class II molecules which play a crucial role in the recognition of exogenous antigens. The abnormalities demonstrated in the function of the light density dendritic cells from the spleens of pregnant mice could compromise cellular reactions to L. monocytogenes bacteria possibly resulting in increased susceptibility of pregnant mice to experimental listeriosis.

Animals↗

PubMed1995

The role of heparan sulphate-binding activity of Helicobacter pylori bacteria in their adhesion to murine macrophages.

The aim of this study was to determine the role of heparan sulphate (HS)-binding activity of Helicobacter pylori microbes in their adhesion to and ingestion by inflammatory peritoneal macrophages. Two H. pylori strains expressing sialic acid-specific haemagglutinins but differing in the expression of heparan sulphate-binding capacity were chosen for investigation. The attachment to an ingestion by macrophages of the H. pylori bacteria were estimated by ELISA using anti-H. pylori antibodies. The adhesion of both H. pylori strains could be inhibited by pretreatment of the bacteria with heparin (H), HS or fetuin, as well as by preincubation of the macrophages with heparinase or neuraminidase. However, detailed analysis of the data on the inhibition of bacterial adhesion to macrophages led to the conclusion that the attachment of H. pylori 25 bacteria, which expressed a high heparan sulphate binding, was mainly determined by HS-binding structures. In contrast, the adhesion to macrophages of H. pylori bacteria 17874 microbes, which expressed a weak heparan sulphate binding, was more dependent on the exhibition of sialic acid-dependent haemagglutinins. The described variation in H. pylori bacterial surface structures mediating their adhesion to macrophages could suggest a similar variation in bacterial adhesion to stomach mucosa and maybe in the pathogenicity of H. pylori strains.

Animals↗

PubMed1995

[Phosphatidylinositol specific phospholipase C (PI-PLC) in differentiation of Listeria monocytogenes and Listeria innocua].

Listeria strains were investigated as regard: the production of PI-PLC and lecytinase, haemolytic and CAMP activity survival in mouse tissues. Although all the examined L. monocytogenes strains produced PI-PLC, they showed a very different activity of this enzyme. It was surprising that one of the four L. innocua strains demonstrated a weak activity of PI-PLC. L. monocytogenes bacteria with strong PI-PLC activity survived in mouse spleens for a much longer period of time than L. monocytogenes microbes with only a weak production of this enzyme. However, L. innocua bacteria producing some PI-PLC were quickly eliminated by infected mice.

Animals↗

PubMed1995

[Usefulness of the microcolorimetric method of XTT reduction for evaluation of intracellular killing of pathogens].

The aim of this study was to evaluate a XTT assay in testing the killing activity of mouse phagocytes in vitro. Live microorganisms converted XTT to water soluble orange formazan in the presence of CQ. Absorption of formazan measured at 492 nm was directly related to the number of viable cells. The percentage of staphylococci killed by granulocytes and macrophages was 10-40% (1 h- and 2 h-respectively), in the cultures containing 10 bacteria/phagocyte. Killing of Candida albicans (1-3 blastospors/phagocyte) was seen after 2 h of incubation. The percentage of Listeria and Mycobacterium killed by phagocytes depended on pathogenicity of the tested strains. The bactericidal activity of phagocytes estimated in the XTT assay and by the CFU method was quite similar.

Animals↗

PubMed1995

The influence of long-lasting implantation on the function of phagocytes towards staphylococci.

A mouse model of peritoneal staphylococcal infection in mice implanted with heparinized polyethylene (H-PE) was used in this study. The binding of staphylococci and fibronectin (Fn) to biomaterial surface was estimated in vitro and in vivo. The activity of phagocytes from the animals non-implanted or implanted for 7 days or 2 months with H-PE was determined on the basis of bactericidal activity, nitric oxide (NO) and Fn production.

Animals↗

PubMed1994

[Feto-maternal immunoregulation].

One of the great mysteries in modern immunology is how extraembryonic membranes escape rejection by maternal immune response, although they express paternal genes/anti-genes which should stimulate allogenic recognition and rejection. Generally, two theories try to explain the pregnancy phenomenon. One of the emphasizes the role of immunosuppressive reactions in the protection of the fetus. On the contrary, the "immunotropism" theory insists on the importance of mother's immune response to paternal antigens of the conceptus. Moreover, the last years abound in discoveries on molecules regulating cell-cell interactions at the level of the initiation and effector stage of the immune response. The best examples of such molecules could be extracellular matrix proteins, integrins, interleukins and various growth factors. The discussion on those molecules as regards their role in the protection of the fetus was the main aim of this article.

Animals↗