Biomedical subjects

J Pryjma

Publications and source records attributed to J Pryjma.

At least 19 recordsLinked to original sources

PubMed2006

Effects of novel plant antioxidants on platelet superoxide production and aggregation in atherosclerosis.

Superoxide anion is produced in human platelets predominantly by Nox2-dependent NADPH oxidases. In vitro experiments have shown that it might play a role in modulating platelet functions. The relationship between platelet superoxide production and aggregation remains poorly defined. Accordingly, we aimed to study superoxide production and aggregation in platelets from subjects with significant cardiovascular risk factors (hypertension, hypercholesterolemia, smoking and diabetes mellitus) and from control individuals. Moreover, we studied the effects of novel polyphenol-rich extracts of Aronia melanocarpa (chokeberry) berries on platelet function in vitro. Superoxide production was significantly increased in patients with cardiovascular risk profile when compared to controls, while platelet aggregation in response to either collagen or thrombin were borderline higher, and did not reach statistical significance. Interestingly, no relationship was observed between platelet aggregation ex vivo and platelet superoxide production in either of studied groups. No correlation was found between endothelial function (measured by FMD) and platelet aggregation ex vivo either. Polyphenol-rich extracts of A. melanocarpa berries caused a significant concentration dependent decrease in superoxide production only in patients with cardiovascular risk factors, while no effect was observed in the control group. A. melanocarpa extracts abolished the difference in superoxide production between risk factor patients and controls. A. melanocarpa extracts exerted significant concentration dependent anti-aggregatory effects in both studied groups, which indicated that these effects may be independent of it's ability to modulate superoxide production. The anti-aggregatory effects of chokeberry extracts were similar irrespective of aggregation inducing agent (collagen or thrombin). Moreover, they appear to be independent of platelet NO release as NOS inhibition by L-NAME did not lead to their abrogation.

Antioxidants↗

PubMed2005

Persistent skin colonization with Staphylococcus aureus in atopic dermatitis: relationship to clinical and immunological parameters.

BACKGROUND: Staphylococcus aureus has important implications for the pathogenesis of atopic dermatitis (AD). In some patients S. aureus can be eradicated from the skin during anti-inflammatory treatment, while in others bacterial colonization is persistent. Potential mechanisms and features of these two distinct groups of patients are not known. OBJECTIVE: Accordingly, we studied relationships between the ability to eliminate S. aureus during an anti-inflammatory treatment and selected clinical and immunological features. METHODS: Quantitative assessment of S. aureus on the skin, in nasal vestibule and throat, serum IgE levels, CD4/CD8 T-cell ratio, lymphocyte proliferation and phagocyte oxidative burst were determined during the exacerbation and after 4 and 12 weeks of the treatment using topical steroid and oral antihistamine in 34 patients with AD. RESULTS: S. aureus was found on the skin of all 34 patients during exacerbation. Disease severity scoring of atopic dermatitis (SCORAD) correlated with the density of bacteria. Treatment with oral antihistamine and topical steroid resulted in a significant alleviation of symptoms, which correlated with the elimination of S. aureus from the skin in 70% of patients. In the remaining 30% of patients, dense (more than 10(10)/cm2) S. aureus skin colonization, persisted despite the treatment. Patients with persistent S. aureus presented with higher serum IgE levels, lower lymphocyte proliferation in response to staphylococcal enterotoxin B, phytohaemagluttinin and anti-CD3. Persistence of S. aureus was more common in men. CONCLUSIONS: Patients with AD differ in the ability to clear S. aureus from the skin during anti-inflammatory treatment, which appears to be related to the abnormalities in immunological parameters. Local antibiotic therapy should be considered only in patients with persistent S. aureus colonization.

Administration, Topical↗

PubMed2002

CD14+CD16+ monocytes in the course of sepsis in neonates and small children: monitoring and functional studies.

The phenotype and function of peripheral blood monocytes change after trauma and during sepsis. The aim of the study was to evaluate monocyte expression of human leucocyte antigen (HLA)-DR and Fc receptor III (FcR III) (CD16) in neonates and small children with high risk of sepsis (hospitalized at the intensive care unit). The reduced proportion of CD14+HLA-DR+ monocytes was observed in all patients at the intensive care unit, while the increase of CD16 expression on monocytes was observed in the course of sepsis. The measurement of CD16 expression on monocytes also proved to be more useful for monitoring patient. The proportion of both CD14dimCD16+ and CD14highCD16+ monocytes increased during sepsis; however, monocytes showed reduced ability to phagocytose Escherichia coli, compromised ability to cooperate with T cells and reduced CD86 expression in parallel to HLA-DR depression. The reduced interleukin (IL)-1 but rather increased IL-10 production was associated with sepsis. The differences between CD14+CD16+ monocytes of healthy donors and patients with sepsis are discussed.

Child, Preschool↗

PubMed2001

Fas (CD95)-Fas ligand interactions are responsible for monocyte apoptosis occurring as a result of phagocytosis and killing of Staphylococcus aureus.

Human peripheral blood monocytes become apoptotic following phagocytosis of Staphylococcus aureus. In this study, we investigated the mechanisms involved in this phenomenon. Cells exposed to bacteria were examined for the surface expression of Fas and Fas ligand (FasL). The level of soluble form of FasL was also measured in the culture supernatants. As Fas-mediated apoptosis involves the activation of caspases, the activities of caspase-8 and caspase-3 were determined. Finally, the involvement of oxidative stress in apoptosis of infected monocytes was investigated. The data indicated that as a consequence of phagocytosis of S. aureus, FasL is released from the monocyte surface and induces apoptosis of phagocytic monocytes and to some extent the bystander cells. The importance of this mechanism was confirmed by demonstrating that blockage of CD95 prevents S. aureus-induced apoptosis of monocytes. Cell death occurring after phagocytosis of S. aureus involves the activation of caspase-3-like proteases, as the specific caspase-3 inhibitor suppressed apoptosis of infected cells. The generation of reactive oxygen intermediates by phagocytic monocytes by itself is not sufficient as a death signal but rather acts in up-regulating FasL shedding and possibly in modulating caspase activity.

Antioxidants↗

PubMed2001

[Selected parameters of the cellular and humoral immunity in atopic dermatitis. Relationship to the severity of the disease].

UNLABELLED: Despite the great progress, our understanding of the pathogenesis of atopic dermatitis (AD) is still incomplete. In particular, the clinical importance of various changes of the immune system parameters is unclear. Accordingly we have undertaken the study to compare selected parameters of cellular and humoral immunity between AD subjects (n = 26) and healthy controls (n = 10). These parameters included immunoglobulin levels (IgE in particular), neutrophil respiratory, oxygen burst, peripheral blood lymphocyte phenotype and response to mitogens. We also analysed the relationship between these parameters and clinical severity of skin lesions. RESULTS: Mean total immunoglobulin E levels were very significantly increased in the AD group (1563 +/- 459 vs 35.5 +/- 12.1 IU/ml; p = 0.001). Simultaneously total serum IgE levels varied extensively between individual subjects with AD and were significantly correlated to clinical severity of the disease (Rs = 0.44; p = 0.02). Atopic dermatitis was also associated with the increase in the number of CD4+ and simultaneous decrease in the CD8+ lymphocytes causing statistically significant difference in CD4:CD8 ratio compared to the control group. We also observed changes of proliferation indices to phytohaemagglutinin (decrease) and increase of responses to anti CD3 mAb (OKT-3) and staphylococcal enterotoxin B. None of these immune parameters however, appeared to be statistically correlated to clinical status. CONCLUSIONS: We find that atopic dermatitis is associated with significant changes of several important indices of cellular and humoral immunity including increased IgE levels and altered peripheral lymphocyte proliferation capacity and phenotype. Change of total IgE levels appears to be the most important from clinical point of view.

Antigens, CD↗

PubMed2001

[Point systems for evaluating coma in patients with injuries of the central nervous system (CNS)].

Paper reviews various coma scales which are used to monitor consciousness after sustaining severe injuries of CNS. Glasgow Coma Scale, at present the most frequently used, was compared to recently developed scales, which are more useful for monitoring persistent comas, allows to evaluate discrete changes in patient's state more precisely and to predict the outcome. The necessity of evoked potentials' measurements, such as Trigeminal-Auditory Glasgow (Coma Scale) has been stressed.

Brain Injuries↗

PubMed2000

Human MO subsets as defined by expression of CD64 and CD16 differ in phagocytic activity and generation of oxygen intermediates.

Phagocytosis and killing of microorganisms by reactive oxygen radicals are important defence mechanisms of the immune system and it was shown that human monocytes (MO) are heterogeneous in exerting these functions. Previously, we described that human peripheral blood MO consist of a major subset of Fc gamma-receptor-I (CD64)-positive cells exhibiting low accessory cell capacity but high phagocytic activity, and a minor subset of CD64-negative cells with dendritic cell (DC)-like high T cell accessory cell capacity but low phagocytic capacity. Recently, we could show that each subset itself further differs in the expression of the Fc gamma-receptor-III (CD16) and T cell accessory activities resulting in four different subsets: two CD16+ subsets (CD64+ or CD64-) with high T cell stimulation capacity and two CD16- subsets (CD64+ or CD64-) with low accessory activities. In the present study we demonstrate that these subsets also differ in their ability to phagocytose opsonized bacteria (S. aureus and E. coli) and in the generation of reactive oxygen species. Both CD64+ subsets (CD16+ or CD16-) exhibit high phagocytic activity accompanied by intracellular superoxide induction. Luminol-dependent (mainly myeloperoxidase (MPO)-mediated) chemiluminescence (CL) response to latex and FMLP (formylmethionylleucylphenylalanine) was also high in these cell populations. Phagocytic activity and modest CL response was shown in CD64-/CD16+ but not in CD64-/CD16- cells, indicating that each subset except for CD64-/CD16- cells may engulf bacteria and exhibit MPO activity. Taken together, these data demonstrate further heterogeneity of peripheral blood MO in both, phagocytic activity and generation of reactive oxygen species indicating differences between the four subsets in this kind of defence mechanisms against pathogens.

Cell Differentiation↗

PubMed1999

Alveolar macrophages of children suffering from recurrent infections of respiratory tract are less efficient in eliminating apoptotic neutrophils.

During bacterial infections of the respiratory tract, neutrophils (PMN) are recruited to the lung by various mechanisms, including production of interleukin-8 (IL-8) by alveolar macrophages (AM). After fulfilling their defense function, PMN become apoptotic and have to be disposed of by AM to prevent local damage to the lung tissue by oxygen species and proteolytic enzymes. We measured the levels of IL-8 in the bronchoalveolar lavage (BAL) and the ability of AM to engulf senescent PMN in a groups of children with and without recurrent infections of the respiratory tract. The IL-8 level was measured by enzyme-linked immunosorbent assay (ELISA). The phagocytosis of apoptotic neutrophils was evaluated microscopically by the presence of myeloperoxidase positive material in AM before and after 1 h of incubation with senescent PMN. The data show that children suffering from recurrent infections have increased IL-8 in BAL and that their AM have a lower ability to engulf apoptotic PMN in vitro. Furthermore, the proportion of annexin V-binding cells was higher in BAL of children with recurrent infections of the respiratory tract than in normal controls.

Adolescent↗

PubMed1999

Induction of reactive oxygen intermediates in human monocytes by tumour cells and their role in spontaneous monocyte cytotoxicity.

The present study examined the ability of human monocytes to produce reactive oxygen intermediates after a contact with tumour cells. Monocytes generated oxygen radicals, as measured by luminol-enhanced chemiluminescence and superoxide anion production, after stimulation with the tumour, but not with untransformed, cells. The use of specific oxygen radical scavengers and inhibitors, superoxide dismutase, catalase, dimethyl sulphoxide and deferoxamine as well as the myeloperoxidase inhibitor 4-aminobenzoic acid hydrazide, indicated that chemiluminescence was dependent on the production of superoxide anion and hydroxyl radical and the presence of myeloperoxidase. The tumour cell-induced chemiluminescent response of monocytes showed different kinetics from that seen after activation of monocytes with phorbol ester. These results indicate that human monocytes can be directly stimulated by tumour cells for reactive oxygen intermediate production. Spontaneous monocyte-mediated cytotoxicity towards cancer cells was inhibited by superoxide dismutase, catalase, deferoxamine and hydrazide, implicating the role of superoxide anion, hydrogen peroxide, hydroxyl radical and hypohalite. We wish to suggest that so-called 'spontaneous' tumoricidal capacity of freshly isolated human monocytes may in fact be an inducible event associated with generation of reactive oxygen intermediates and perhaps other toxic mediators, resulting from a contact of monocytes with tumour cells.

Adenocarcinoma↗

PubMed1999

Heat-shocked monocytes are resistant to Staphylococcus aureus-induced apoptotic DNA fragmentation due to expression of HSP72.

Human peripheral blood monocytes became apoptotic following phagocytosis of Staphylococcus aureus. The consequences of heat stress for monocytes were studied with regard to the effect on S. aureus-induced apoptosis. Exposure of monocytes to 41.5 degrees C for 1 h resulted in HSP72 expression and had no influence on phagocytosis of bacteria; moreover, phagocytosis of S. aureus immediately or shortly after heat shock had no effect on the S. aureus-induced monocyte apoptosis, as evidenced by DNA fragmentation assay. In contrast, cells which recovered from heat shock for 18 to 24 h, although active as phagocytes, were resistant to the S. aureus-induced apoptosis. The observed protective effect was related to the induction of HSP72, since blocking of HSP72 synthesis by an antisense oligomer abolished the protective effect of heat shock on bacterium-induced monocyte apoptosis.

Apoptosis↗

PubMed1999

The role of cytokines in monocyte apoptosis.

Survival or apoptosis, activation and differentiation, phagocytosis and antigen presentation, migration or participation in granuloma formation are features of freshly recruited blood-borne monocytes in the local environment. In this presentation we describe that human monocytes undergo spontaneous apoptosis in vitro which involves Fas/FasL interactions, and that proinflammatory cytokines such as tumor necrosis factor-alpha (TNFalpha), interleukin-1beta and granulocyte-monocyte-colony-stimulating factor prevent spontaneous apoptosis. In vitro infection of purified monocytes with low numbers of Mycobacterium tuberculosis H37Rv prevents spontaneous apoptosis. The apoptosis-preventing effect is correlated to the release of TNFalpha and not due to phagocytosis per se. Furthermore, the minor subset of CD64-negative monocytes is found to be less susceptible to recall antigen-activated CD4-positive T cell-mediated apoptosis than CD64-positive monocytes. Finally, recent findings of our group indicate that the chemokine platelet factor 4 protects monocytes from spontaneous apoptosis and induces the differentiation of monocytes into macrophages. From these findings we conclude that monocyte recruitment, their survival, their differentiation and their functional activity at the site of inflammation are regulated by a cytokine network which needs to be further analyzed in order to design strategies for immune intervention.

Antibodies, Bacterial↗

PubMed1998

Detection of cancer cells in the blood by FACS sorting of CD45- cells.

We describe a simple and sensitive method for detection of low number of cancer cells in the blood. The method is based on FACS sorting of leukocytes labelled with anti-CD45 monoclonal antibody and examining CD45- cells by conventional cytology and immunostaining for cytokeratin 18. In a model study, cancer cells seeded at the frequency of 1 per 106 and 1 per 107 leukocytes were detected in CD45- population. Sensitivity of this method was comparable to reverse transcription polymerase chain reaction (RT-PCR) used for detection of cancer cells expressing CD44 variants-mRNA. In a pilot study, cancer cells were also isolated from the blood of some patients with locally advanced gastric cancer. This method may be useful for detection of circulating tumour cells in cancer patients.

Blood Cells↗

PubMed1998

Apoptosis in monocytes.

Apoptosis is a major mechanism for reducing acute inflammation by elimination of unwanted cellular responses causing tissue damage and monocytes (Mo) and macrophages (Mo) play an important role in these processes. Therefore, in the following we summarize how these cells may contribute to regulation of apoptosis of other cells and discuss the factors involved.

Animals↗

PubMed1997

Oncostatin M stimulates the expression and release of the IL-6 receptor in human hepatoma HepG2 cells.

Soluble IL-6R (sIL-6R), which lacks the transmembrane domain, has been suggested to be a potent immunomodulator of IL-6 biologic activity. In this study, the ability of cells of hepatic origin to generate the sIL-6R was investigated. It was found that oncostatin M alone or in combination with the glucocorticoid analogue dexamethasone significantly up-regulated IL-6R release. Oncostatin M appeared to generate the sIL-6R primarily through an alternative splicing mechanism. Since sIL-6R is able to form biologically active complexes with IL-6, the release of the sIL-6R from hepatocytes may be important to sensitize cells lacking the membrane-bound receptor, particularly during an acute phase reaction.

Alternative Splicing↗

PubMed1997

An Fc gamma receptor I (CD64)-negative subpopulation of human peripheral blood monocytes is resistant to killing by antigen-activated CD4-positive cytotoxic T cells.

It has been demonstrated that in monocyte/T cell co-cultures activated with recall antigens, cytotoxic T cells were generated which are able to reduce the number of antigen-presenting monocytes. In previous studies we could show that a minor subset of monocytes, the Fc gamma receptor I-negative (CD64-) monocytes, exhibits significantly higher antigen-presenting capacity than the main population of monocytes (> 90%) which are Fc gamma receptor I-positive (CD64+). Therefore, we addressed the question whether they are also differentially susceptible to T cell-mediated killing. In the present study we demonstrate that the CD64- monocyte subset is more resistant to killing by antigen-activated T cells than CD64+ monocytes, as indicated by a higher viability and recovery of CD64- monocytes. This mechanism involves CD95 (Fas) antigen, since monocyte death in co-cultures with antigen-activated T cells could be partially reduced by blocking anti-Fas monoclonal antibodies (mAb). In agreement with this finding, although CD95 antigen was expressed on CD64+ and CD64- monocytes at comparable levels, killing of CD64- monocytes by activating anti-Fas mAb was lower than of CD64+ monocytes.

CD4-Positive T-Lymphocytes↗

PubMed1996

Effect of soluble interleukin-6 receptor on interleukin-6 synthesis in human skin fibroblasts.

In this study the ability of soluble interleukin-6 receptor (sIL-6R) to stimulate interleukin-6 (IL-6) synthesis in human fibroblasts is described. It was found that sIL-6R, in combination with endogenous or exogenous IL-6, markedly upregulated IL-6 synthesis. These data suggest that increased IL-6 production after stimulation by either interleukin-1 or tumor necrosis factor-alpha would result in complex formation with sIL-6R, rapid uptake, and further synthesis of this cytokine. Furthermore, it would explain the decrease in sIL-6R plasma levels observed in patients suffering from sepsis.

Antigens, CD↗

PubMed1996

Apoptosis of monocytes and prolonged survival of granulocytes as a result of phagocytosis of bacteria.

Monocytes and granulocytes were incubated with suspensions of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, or Salmonella enteritidis and, after being washed free of bacteria, cultured for up to 48 h. Every few hours, samples of cultured cells were taken for DNA isolation. Monocytes which phagocytosed bacteria showed features of apoptotic cells, as determined by light microscopy and DNA fragmentation detected by gel electrophoresis. The phenomenon was observed 2 to 4 h after phagocytosis, in contrast, control monocytes did not show signs of apoptosis until 48 h of culture. Intact control granulocytes spontaneously became apoptotic after 12 h of culture. In contrast, degradation of DNA in cells exposed to bacteria was delayed by 12 to 24 h. In conclusion, our observation suggests that granulocytes and monocytes react differently to phagocytosis of bacteria.

Apoptosis↗

PubMed1995

Interaction of HIV-1 gp120 molecule fragments with human monocytes: different requirements for tumor necrosis factor-alpha and IL-6 production.

The HIV-1 gp120 recombinant protein fragment encompassing aa residues 410-511, that contains the CD4 binding region (rp120cd), and fragment aa 446-511, which lacks the sequence responsible for CD4 binding (rp120), were synthesized to study their ability to induce TNF synthesis in human monocytes. The rp120cd stimulated TNF alpha secretion by monocytes while the rp120 and full-length recombinant protein (FL gp120), used as control, failed to do so. However, FL gp120 stimulated peripheral blood mononuclear cells (PBMC) and lymphocytes for TNF production and this was inhibited by anti-CD4 MAb. The rp120cd also caused TNF secretion by PBMC that was not blocked by this antibody. Furthermore, FL gp120 but not rp120cd inhibited anti-CD4 mAb binding to CEM cells. Hence, FL gp120 may cause TNF release from lymphocytes by binding to CD4, while rp120cd interacts with monocytes but not lymphocytes and induces TNF production by a mechanism not involving CD4 binding. Unexpectedly, FL gp120 but not rp120cd stimulated IL-6 secretion and IL-6 mRNA synthesis in monocytes. The FL gp120-induced production of IL-6 by monocytes was inhibited by anti-CD4 monoclonal antibody (MAb). Thus, there may be different requirements for TNF induction in lymphocytes and monocytes stimulated with various preparations of gp120 and for the selective induction of cytokines in monocytes. The enhanced production of TNF in HIV infection and AIDS may involve distinct cellular sources and different mechanisms.

Antibodies, Monoclonal↗