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Biomedical subjects

W Rudnicka

Publications and source records attributed to W Rudnicka.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1994

Specific cellular and humoral reactions as markers of Listeria monocytogenes infections.

The purpose of the study was to test in experimental mouse model if some immunological parameters could be helpful in recognizing Listeria infections. Delayed type hypersensitivity (DTH) and ELISA tests carried out with soluble fractions of L. innocua (serotype 6a) or L. monocytogenes (serotype 4b) seem to be useful in detecting listeriosis at an early stage. Although crude antigen fractions were used in this study, very weak only nonspecific DTH reactions were observed in unifected animals and they could be easily distinguished from the DTH reactions developed by the animals infected with Listeria. However, genetic factors influenced specific anti-listerial reactivity and it was especially observed when DTH test was used as an indicator of Listeria infection. In contrast to DTH and ELISA tests, determination of antibodies active in agglutination or passive haemagglutination assay seem useless in detecting listeriosis at an early stage of infection.

Agglutination Tests↗
PubMed1993

[Weakness of cellular response to Listeria antigens in pregnant mice].

It was found that pregnant mice exhibit increased susceptibility to lethal action of Listeria monocytogenes, although there was no correlation between increase of susceptibility of animals to lethal effect of bacteria and weakening of elimination of microorganisms from the spleen. Increased susceptibility of animals to listeriosis was accompanied by weakening of some parameters of cellular immunity. In pregnant mice of strains C57Bl/6, naturally resistant to infections, inhibition of II-1 by macrophages was found which at the same time exhibited depression of chemotaxis. Weakening of these macrophage functions did not influence the development of delayed hypersensitivity to Listeria antigen (LA) in C57Bl/6 mice--the reaction which was suppressed in pregnant mice of A/J strain which is characterized by natural susceptibility to listeriosis. Inhibition of development of delayed hypersensitivity to LA in A/J pregnant mice was caused by defective function of dendritic cells and T lymphocytes. Dendritic cells of A/J pregnant mice exhibited limited ability of presentation of LA to immune T lymphocytes isolated from animals infected with L. monocytogenes or L. innocula. On the other hand, immune T cells of A/J mice cultured with LA exhibited inhibition of proliferation and production of MIF.

Animals↗
PubMed1993

[Protective action of anti-listeria IgG].

It was found that single injection into mice of 70 micrograms IgG against Listeria innocua protected them against lethal action of virulent cell of L. monocytogenes, if antibodies were injected 1-3 weeks before infection. Immune IgG did not exert the protective effect when injected one day before infection. Mice T lymphocytes receiving immune IgG three weeks before infection, exhibited increased ability to direct interactions (cluster formation) with dendritic cells presenting Listeria antigen (LA). At the same time, sera obtained from these animals were blocking the reaction of indirect haemagglutination occurring between antibodies against L. innocula and LA-covered sheep erythrocytes. These results suggest that anti-listerial IgG are inducing in mice production of anti-idiotypic antibodies. Most probably, some of these immunoglobulins imitate determinants of Listeria antigens, copying their three-dimensional structure. They could activate T cells specific against bacterial antigens (1st signal of activation). Introduction of virulent L. monocytogenes cells into mice possessing T cells activated by anti-idiotypic antibodies, could create a second antigenic signal, resulting in intensive elimination of bacteria by mechanisms of specific cellular immunity.

Animals↗
PubMed1992

LFA-1-dependent OKT3-driven T cell clusters in common variable immunodeficiency.

The triggering of the TCR/CD3 complex by anti-CD3 (OKT3) antibody leads to the formation of T cell clusters. In cultures of T lymphocytes from most normal individuals, the peak of cluster formation occurs at 24 h, but with cells from patients with common variable immunodeficiency (CVI) it was seen earlier at 4-9 h; in addition, the clusters were larger than normal, particularly at 9 h. Cluster formation by CVI and normal cells was dependent on temperature and divalent cations, but did not require Fc receptors. Since OKT3 clustering is known to be dependent on the LFA-1/ICAM-1 adhesion system, the effect of monoclonal antibodies directed against these molecules was tested. A potent inhibitor was the antibody against the common beta chain of the integrin family (CD18), but of four MoAbs against the alpha chains (CD11), three inhibited and one stimulated T cell aggregate formation. Increased expression of LFA-1 or ICAM-1 on CVI patients' T cells could not be demonstrated. The accelerated clustering was therefore probably due to an increase in the proportion of cells carrying the activated form of LFA-1. The formation of large numbers of homotypic lymphocyte clusters might reduce the effective interaction between B and T cells, thus contributing to the depression of immunoglobulin synthesis observed in this disease.

Adolescent↗
PubMed1992

Synthesis, structure and biological activity of 1,2,4-triazolo-1,3-thiazine derivatives.

A group of condensed triazole-thiazine derivatives (2a-i, 3b, 3j) was obtained in reaction of the corresponding 5-substituted 1,2,4-triazole-3-thiones (1a-j) with epichlorohydrin in alkaline medium. The structure of the compounds synthesized was confirmed by spectral and roentgenographic methods. Tuberculostatic and circulatory activities of the compounds were also studied.

Animals↗
PubMed1991

Effects of gonadotrophin on resistance to Listeria monocytogenes infection in mice.

It was demonstrated that exogenous GH suppressed the resistance to L. monocytogenes infection in Listeria resistant C57Bl/6 and susceptible A/J mice. However, different parameters of the immunological reaction to Listeria were affected by GH treatment in these mouse strains. In C57Bl/6 mice GH decreased accumulation of macrophages at the inflammatory site. On the contrary, a depression of anti-listerial activity of the phagocytes and a reduction of DTH reaction to Listeria antigen was demonstrated in GH treated A/J mice.

Animals↗
PubMed1989

Cellular immune response to Listeria in genetically resistant and susceptible mouse strains.

Relatively Listeria-resistant C57B1/6 mice and more susceptible to the infection DBA/2 mice were immunized with Listeria-antigen (LA). Immunized DBA/2 mice developed weaker delayed hypersensitivity to LA and still eliminated listeriae less effectively than identically immunized C57B1/6 mice. An accessory function of LA-pulsed macrophages of normal C57B1/6 mice was only slightly enhanced as compared with LA-pulsed macrophages of DBA/2 mice. It is suggested that some suppressor lymphocytes, IgM+ and/or FcR+, could be responsible for the enhanced susceptibility of DBA/2 mice to listeriosis.

Animals↗
PubMed1988

Phagocytosis and killing of Listeria by guinea pig macrophages and neutrophils.

The rate of the phagocytosis and intracellular killing of Listeria monocytogenes by guinea pig macrophages and neutrophils in vitro was determined. The anti-bacterial activity of the phagocytes against virulent Listeria monocytogenes was compared with their activity against avirulent strain of Listeria and Proteus mirabilis. It is suggested that the contribution of the macrophages and the neutrophils to anti-bacterial protection can depend on physiological state of bacteria.

Animals↗
PubMed1988

Innate anti-listerial resistance of mice differing in their susceptibility to listeriosis.

The work was designated to compare the influence of an active immunization on the expression of anti-listerial resistance of relatively resistant to listeriosis C57B1/6 mice as compared with more susceptible to the infection DBA/2 mice. Although, specific immunization of DBA/2 mice enhanced their anti-listerial resistance but immunized DBA/2 mice still eliminated Listeria rods less effectively than immunized C57B1/6 mice. It means that innate difference in anti-listerial resistance between C57B1/6 and DBA/2 mice was maintained after immunizing them with the same number of alive bacteria. Greater anti-listerial resistance of C57B1/6 versus DBA/2 mice is associated with an increased accumulation of inflammatory Ms and PMNs in their peritonea and an increased capacity of their PMNs to restrict Listeria growth.

Animals↗
PubMed1985

Listeria antigen-binding cells in the spleens of normal and immunized mice resistant or susceptible to listeriosis.

Normal mice of the Listeria-resistant C57Bl/6 strain contain in their spleens a higher number of cells that bind Listeria monocytogenes cell wall fraction antigen (LmA) than normal DBA/2 mice, which are more susceptible to infection. LmA-binding cells are probably B cells, nylon-wool adherent, and inhibited by anti-mouse immunoglobulin antibody but not sensitive to the action of monoclonal anti-mouse macrophage and anti-Thy.1.2 antibody. A single intraperitoneal injection of 10(8) Listeria monocytogenes causes a rapid increase in the number of LmA-binding cells in the spleens of C57Bl/6 mice, and this can be seen as early as 24 h. On the other hand, in DBA/2 mice an increase in these cells becomes evident only by the 4th day. Moreover, the increment in the number of LmA-binding cells in C57Bl/6 mice is more marked than in DBA/2 mice.

Animals↗