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  • 1
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract This study set out to investigate the in vivo expression and distribution of the porcine homologues of the intercellular adhesion molecule-1 (ICAM-1) and MHC Class II as markers of chondrocyte activation during the development of chronic polyarthritis, which was experimentally induced in Landrace pigs by intra-articular injection of Erysipelothrix rhusiopathiae. ICAM-1 was found to be strongly expressed in vivo on chondrocytes and synovial cells in arthritic joints but was not detected in cartilage from unaffected joints. Although the majority of ICAM-1 positive chondrocytes did not co-express MHC Class II, chondrocyte-type cells expressing both molecules were detected in the transition zone as the disease progressed, particularly at 5 months post-infection. At this stage infiltration of CD4+ T lymphocytes into the damaged cartilage was also apparent. ICAM-1 and MHC Class II are not constitutively expressed on porcine chondrocytes but appeared to be induced as arthritis progressed. The detection of these markers in the pig helps to establish the validity of this animal model for immunopathological studies.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract The survival of Helicobacter mustelae, Proteus mirabilis, Escherichia coli and Campylobacter jejuni in the presence of urea and citrate at pH 6.0 was examined. H. mustelae, which has urease activity similar to H. pylori, had a markedly reduced survival, median 2.5% (0–78%) (P〈0.001) when incubated nder these conditions. Only 7% of the ammonia produced by H. mutelae urease activity was recovered from the buffer, a similar percentage to that previously reported with H. pylori. None of the other organisms, all of which had lower urease activity, had impaired survival under these conditions. Electron microscopical studies demonstrated extensive structural damage to H. pylori following exposure to urea and citrate at pH 6.0. This structural damage to the organisms makes it unlikely that the low recovery of ammonia was due to retention of ammonia within the bacteria and suggests that the ammonia may have been incorporated into glutamate or other amino acids. Incorporation of ammonia into these compounds would deplete the cell of the key metabolic intermediate α-ketoglutarate and could thus explain the mechanism of the urease-dependent destruction of the organism.
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  • 3
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract Guinea pigs were given a preparatory injection of heat-killed Mycobacterium tuberculosis in a water-in-mineral oil emulsion. A provocative injection of muramyldipeptide given 3–8 weeks later into the footpads, caused severe inflammation, with hemorrhage and necrosis. In this study, we determined the features of the preparatory injection required to prepare the necrotic reaction. Most mycobacteria-related and Gram-negative bacteria were capable of preparing guinea pigs for the necrotic reaction upon provoactive injection with muramyldipeptide, whereas Gram-positive bacteria did not. Boivin- and Morrison-type lipopolysaccharides, which have a high content of bacterial protein, induced the susceptibility, whereas Westphal-type lipopolysaccharide, which has a low level of the protein, did not. Moreover, the latter adjuvant-active lipopolysaccharide and muramyldipeptide together with ovalbumin also exerted the activity. The development of delayed-type hypersensitivity to the protein antigen seemed to be important for inducing the necrotic reaction. Mice, rats, rabbits and monkeys were injected in the same way as the guinea pigs. The necrotic reaction occurred in the flanks of the monkeys, but not in the other animals. A similar necrotic reaction also occurred in the flanks of guinea pigs given live BCG cells in phosphate-buffed saline as well as the heat-killed M. tuberculosis in water-in-mineral oil emulsion upon provoactive injection with muramyldipeptide. These findings suggested that the induction is associated with the development of delayed-type hypersensitivity to the protein antigen administered in the preparatory injection.
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  • 4
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract The lack of experimental models suitable for the study of meningococcal pathogenicity led us to investigate if thoses actually in use (culture in iron-restricted media and animals models) provide results comparable with the responses observed in vivo during infection. In this work we studied three invasive strains cultured both in laboratory media and in human plasma, analysing the immune response elicited in mice against membrane antigens and comparing them with those seen using homologous human convalescent sera. Outer membrane protein profiles observed after culture in plasma were different and more complex than those obtained after growth in laboratory media. Analogous differences were observed in the antigenic profiles, detecting some antigens recognized by human, but not mouse sera, and vice sersa. However, the response to one of the major iron-regulated outer membrane antigens, the transferrin binding protein 2 (TBP2), was unaffected by the culture medium or the model, human or mouse, used for the analysis. In conclusion, we have found that results of antigenic analysis change depending on the culture conditions and animal models used. For the meningococcal antigen TBP2, growth in iron-restricted laboratory media and a mouse model provide results which correlate well with those observed using convalescent human serum from individuals recovered from infections. We suggest that careful analysis and evaluation of experimental results and their comparison with in vivo elicited immune responses are essential in order to get accurate extrapolations for experimental vaccine designs.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract Several studies have demonstrated that Bordetella pertussis has the ability to enter and survive intracellularly within human polymorphonuclear leukocytes (PMNL) and human monocytes/macrophages. The effects of human recombinant gamma interferon (IFN-γ) on the survival of B. pertussis in PMNL and human monocytes, and on the oxidative burst activity of PMNL and human monocytes in response to B. pertussis were assessed in this study. IFN-γ partially increased intracellular killing of phagocytosed B. pertussis in human monocytes, as determined by an orange acridine-crystal violet assay. In contrast, IFN-γ did not enhance intracellular killing of B. pertussis in PMNL. No significant increase of superoxide production was noted in human monocytes in response to B. pertussis when stimulated with various concentrations of IFN-γ. The partial increase of B. pertussis killing by IFN-γ within monocytes, together with poor production of superoxide may explain how B. pertussis can survive within human phagocytic cells, and thus cause a more prolonged course of the disease.
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  • 7
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract This study describes a series of immunological investigations carried out on a group of 37 HIV-seropositive children, aged 3–4 years, in two different stages of disease defined according to the CDC classification; the Primary stage, an asymptomatic one, showing abnormal immune function (P1-Class, B-Subclass) and the Secondary stage, 6–8 months later, in which patients exhibited non-specific findings, i.e., loss of weight, persistent generalized lymphadnopathy and hepatosplenomegaly, associated with abnormal immune function (P2-Class, A-Subclass). In both stages, immune function was considered ‘abnormal’ when lymphopenia and a decrease of the CD4/CD8-cell ratio were found. The phenotypes CD16+/56+ (NK) and HLA-DR+/CD3+ (T-activated?)-positive cells, were assesed by flow cytometry, and the following supplementary systemic humoral markers were investigated in homologus serum samples; total HIV(gp)-antibody, HIV(p24)-antibody and p24-antigen presence. If at the primary stage, no significant difference from to the reference values corresponding to the age was noticed, at the Secondary stage the obtained data is presented separately in two subgroups, namely the A-subgroup characterized by the presence of total HIV(gp)-antibody the presence of HIV(p24)-antibody and the absence of p24-antigenaemia, and the B-subgroup, where total HIV(gp)-antibody was present, HIV(p24)-antibody absent and p24-antigenaemia present. A significant decrease of CD16+/56+ (NK)-cells was found within the two subgroups. As far as HLA-DR+ from CD3+-cells was concerned, only those within the B-subgroup showed a high percentage level, compared to the reference values. The importance of the present findings, linked to immune monitoring of HIV infection among children, is discussed.
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  • 8
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract A total of 80 Escherichia coli strains were examined for expression of P-fimbriae, mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) of human group A erythrocytes and guinea pig erthrocytes, cell surface hydrophobicity and resistance to serum bactericidal activity. Isolates were obtained from urine of children and adults, either with acute pyelonephritis (n = 15 and n = 12) or lower urinary tract infection (UTI) (n = 30 and n = 23, respectively). Results obtained showed that, in E. coli strains isolated both from children and adults with lower UTI, significant differences were not found concerning the incidence of P-fimbriae, cell surface hydrophobicity and serum resistance. In pyelonephritogenic E. coli isolated from children and adults, the incidence of P-fimbriae and cell surface hydrophobicity was associated more frequently with the former (87% vs. 42% and 100% vs. 67%, P 〈 0.05), while serum resistance was associated with the latter (47% vs. 67%, P 〈 0.05).
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  • 9
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Abstract Three micro-enzyme-linked immunosorbent assay (micro-ELISA) systems were developed and evaluated for detection of specific free circulating antigen and circulating immune-complexes (CICs) of 8 kDa antigen in the sera of patients with hydatidosis. All (100%) the sera of 30 confirmed positive cases of hydatidosis had detectable levels of antigen in the acid-treated sera. However, 23 (77%) and 26 (87%) sera of 30 confirmed cases had free as well as CICs of 8 kDa antigen in the untreated and in the polyethylene glycol (PEG) precipitated sera, respectively. None of the sera from other patients with parasitic infections or viral hepatitis had any detectable levels of 8 kDa antigen in the untreated, acid-treated or PEG-precipitated serum samples. The investigations, therefore, suggested that the demonstration of circulating antigen employing monospecific antibodies to affinity purified 8 kDa antigen in acid-treated sera is more efficient as compared to detection of free circulating antigen of CICs in the untreated or in the PEG-precipitated sera which could provide a specific immunodiagnostic tool for ongoing hydatid infection.
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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