Biomedical subjects

B Rózalska

Publications and source records attributed to B Rózalska.

At least 19 recordsLinked to original sources

PubMed1999

Evaluation of the API test, phosphatidylinositol-specific phospholipase C activity and PCR method in identification of Listeria monocytogenes in meat foods.

The aim of this work was to compare the possibility of identifying Listeria monocytogenes strains isolated from meat and sausage on the basis of the API-Listeria test, production of phosphatidylinositol-specific phospholipase C (PI-PLC) and polymerase chain reaction (PCR) for a DNA fragment of the hlyA gene encoding listeriolysin O. Forty-six strains were isolated and examined. The lethality of some Listeria isolates for BALB/c mice was also determined. In this study, all isolates identified as L. monocytogenes in the API test gave a positive signal in the PCR. Listeriae identified as L. innocua or L. welshimeri in the API test were negative in the PCR conducted with the primers for listeriolysin O. All strains identified as L. monocytogenes on the basis of the API test and the PCR produced PI-PLC. However, this activity was not limited to the bacteria of this species. Four out of 17 L. innocua and three out of 10 L. welshimeri isolates were PI-PLC-positive. None of the L. innocua or L. welshimeri isolates (neither PI-PLC+ or PI-PLC-) showed lethality for BALB/c mice. In contrast, two L. monocytogenes isolates as well as a reference L. monocytogenes strain killed all mice used for the experiment.

Animals↗

PubMed1999

Saccharomyces cerevisiae IRR1 protein is indirectly involved in colony formation.

The ability of a microorganism to adhere to a solid support and to initiate a colony is often the first stage of microbial infections. To date, studies on S. cerevisiae cell-cell and cell-solid support interactions concerned only cell agglutination during mating and flocculation. Colony formation has not been studied before probably because this species is not pathogenic. However, S. cerevisiae can be a convenient model to study this process, thanks to well-developed genetics and the full knowledge of its nucleotide sequence. A preliminary characterization of the recently cloned essential IRR1 gene indicated that it may participate in cell-cell/substrate interactions. Here we show that lowering the level of expression of IRR1 (after fusion with a regulatory catalase A gene promoter) affects colony formation and disturbs zygote formation and spore germination. All these processes involve cell-cell or cell-solid support contacts. The IRR1 protein is localized in the cytosol as verified by immunofluorescence microscopy, and confirmed by cell fractionation and Western blotting. This indicates that Irr1p is not directly involved in the cell-solid support adhesion, but may be an element of a communication pathway between the cell and its surroundings.

Blotting, Western↗

PubMed1998

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-coated implants and their potential for reducing biomaterial-associated infection in neutropenic hosts.

The incidence of infections associated with the use of medical biomaterials is high for skin-penetrating devices, when microbes of the normal skin flora like coagulase-positive and coagulase-negative staphylococci dominate as causative organisms. The most serious ones are infections in immunocompromised individuals. A mouse model of subcutaneous staphylococcal infection yielding abscesses in cyclophosphamide-induced neutropenic mice implanted with heparinized polyethylene (H-PE) was used. The present study addresses the question of the effects of implant modification with recombinant granulocyte-macrophage stimulating factor (rGM-CSF) on the course of infection. Our findings demonstrate that such modification reduces the proliferation of bacteria within the abscess and as a consequence limits the dissemination of bacteria from the local infection induced in the neutropenic host.

Abscess↗

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

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

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↗

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

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↗

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

[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

[Interdependence of the immune system and structure of extracellular matrix proteins].

The major proteins from plasma and extracellular matrices (ECM) are described. The interaction of lymphoid cells with their microenvironment is critical for their growth and function. The interaction with ECM may play a significant role in defining the biological properties of many cells. ECM form a network of bioactive proteins, that is being linked with an increasing number of processes, including antigen-independent activation, proliferation, homing and cell migration. Some aspects of the participation of the extracellular matrix in the language of intracellular communication is discussed.

Cell Communication↗

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↗