The CC chemokine receptor 3 CCR3 is functionally expressed on eosinophils but not on neutrophils.

The chemokine subclasses differ in their biological activity to stimulate different kinds of effector cells via distinct chemokine receptors. Controversial results about the expression of the CC chemokine receptor CCR3 on the surface of human neutrophils have been described. To find out whether eosinophil contamination might be responsible for these diverse observations, CCR3 expression on highly purified neutrophils and eosinophils was investigated. We enriched neutrophils from a heterogeneous granulocyte population with immunomagnetic beads coated with various anti-CD52 monoclonal antibodies. This procedure was suitable to enrich neutrophils with a purity of up to 99.85%. Reverse transcriptase-PCR revealed that CCR3 mRNA was not expressed by CD52-negative selected neutrophils. In contrast to these cells, CCR3 mRNA could be detected in a heterogeneous granulocyte population and CD16-negative selected eosinophils. In addition, spectrofluorometric measurement of intracellular calcium concentration ([Ca2+]i) demonstrated that CD52-negative selected neutrophils did not show a transient [Ca2+]i increase following stimulation with the CCR3 ligand eotaxin, whereas the heterogeneous granulocyte population as well as eosinophils did respond. Therefore, previous studies demonstrating the expression of CCR3 on human neutrophils have to be re-evaluated because CCR3 mRNA detection on human neutrophils due to contamination by mRNA from eosinophils could not be excluded.

Immediate placement of an endosseous root-form implant in an HIV-positive patient: report of a case.

Use of combination antiretroviral therapy regimens, including a protease inhibitor, has greatly improved the survival and systemic health of HIV-positive patients. Due to the esthetic requirements of the patient in this case report, placement of an endosseous implant into a fresh extraction site, restored with a single crown, was the treatment of choice. The implant and restoration are functioning well 18 months after placement of the fixture.

Detection of MCP-4 in dermal fibroblasts and its activation of the respiratory burst in human eosinophils.

CC-chemokines are an important family of proinflammatory mediators that promote the recruitment and activation of human eosinophils in chronic inflammatory diseases. Recently, a novel human CC-chemokine, monocyte chemotactic protein 4 (MCP-4), has been reported that shows amino acid sequence similarities with eotaxin and RANTES, induces chemotaxis of eosinophils, and signals through specific chemokine receptors. In this study, we investigated the effect of MCP-4 on different eosinophil effector functions leading to the activation of the respiratory burst. In human eosinophils, MCP-4 dose dependently induced the production of reactive oxygen species and actin polymerization as a related event. Pretreatment of eosinophils with different enzyme inhibitors interacting with the signal transduction cascade revealed that Gi protein, protein kinase C, tyrosine kinase, and phosphatidylinositol-3-kinase are involved in the signaling following stimulation with MCP-4. In addition, cytokine-stimulated human dermal fibroblasts expressed high levels of MCP-4 mRNA, suggesting that fibroblasts are a physiologic source of MCP-4. Therefore, this study demonstrates that there is an important role of MCP-4 in the activation of eosinophils and that the interaction between dermal fibroblasts and human eosinophils may play an important role within the cytokine network.

The CC chemokine antagonist Met-RANTES inhibits eosinophil effector functions through the chemokine receptors CCR1 and CCR3.

Eosinophils are predominant effector cells not only in allergic diseases but also in connective tissue diseases. The recruitment of eosinophils to the site of inflammation and release of reactive oxygen species leading to tissue damage and propagation of the inflammatory response are mediated by chemokines. Thus, agents that would be able to inhibit or antagonize chemokine-induced eosinophil activation are interesting as therapeutical agents. We describe the effect of a chemokine receptor antagonist, Met-RANTES, on human eosinophil effector functions in response to RANTES, monocyte chemoattractant protein (MCP)-3 and eotaxin. Met-RANTES was able to inhibit dose-dependently [Ca2+]i transients in eosinophils following stimulation with RANTES, MCP-3 and eotaxin. Whereas maximal and half-maximal inhibitory effect of Met-RANTES following stimulation with RANTES and MCP-3 were observed at 2 micrograms/ml and 1 microgram/ml, respectively, maximal and half-maximal inhibitory effects of Met-RANTES in response to eotaxin were detected at 10 micrograms/ml and 3 micrograms/ml. Moreover, eotaxin-induced [Ca2+]i transients were only half reduced at a Met-RANTES concentration at which RANTES and MCP-3 were completely blocked. Besides its effect on [Ca2+]i transients, Met-RANTES dose-dependently inhibited actin polymerization in eosinophils following chemokine stimulation. Whereas Met-RANTES totally inhibited RANTES- and MCP-3-induced actin polymerization at 5 micrograms/ml, the eotaxin-induced response was only reduced by 50%. However, Met-RANTES inhibited dose-dependently the release of reactive oxygen species in response to RANTES, MCP-3 and eotaxin. Again, eotaxin-induced release of reactive oxygen species, however, was only half reduced at a Met-RANTES concentration (10 micrograms/ml) at which RANTES and MCP-3 were completely blocked. The results of this study show that (1) Met-RANTES is an effective and powerful antagonist of effector functions of human eosinophils following stimulation with RANTES, MCP-3 and eotaxin; (2) Met-RANTES seems to be able to antagonize the response of eosinophils through chemokine receptor 1 (CCR1) preferentially to CCR3; (3) Met-RANTES antagonizes eosinophil but not neutrophil effector functions and might be therefore of interest for a new therapeutical approach to prevent the invasion and destructive power of eosinophils in diseases that are accompanied by eosinophil infiltration such as allergic asthma and connective tissue diseases.

Surface and mRNA expression of the CD52 antigen by human eosinophils but not by neutrophils.

Eosinophilic and neutrophilic granulocytes represent major effector cells in the inflammatory response. Whereas neutrophils are predominantly involved in bacterial infections, eosinophils are of essential importance in the allergic inflammation. Surface markers have been used to distinguish neutrophils (CD16+) from eosinophils (CD16-) and might indicate different functional properties of these cells. In this study, expression and functional activity of CD52 on human eosinophils and neutrophils was investigated in nonatopic healthy donors and from patients with hypereosinophilia. Flow cytometric analysis using different anti-CD52 monoclonal antibodies (MoAbs) (mouse IgG3, humanized IgG1, and rat IgM) showed significant and homogeneous expression of CD52 on human eosinophils, but not on neutrophils. In addition, reverse transcription-polymerase chain reaction and Northern blot analysis showed that CD52 mRNA was constitutively expressed in eosinophils but not in neutrophils. Furthermore, expression of CD52 could be diminished in a dose-dependent manner by preincubation of eosinophils with phosphatidylinositol-specific phospholipase C, suggesting that CD52 on eosinophils is anchored to the membrane through a glycosylphosphatidylinositol (GPI) molecule. Whereas the phorbolester phorbol myristate acetate was able to downregulate the expression of CD52 on eosinophils in a dose-dependent manner, different eosinophil activating cytokines and chemotaxins had no effect. Cross-linking of CD52 by mouse anti-CD52 MoAb (IgG3) and humanized anti-CD52 MoAb (IgG1) with goat antimouse antibody and mouse antihuman antibody, respectively, dose-dependently resulted in an inhibition of reactive oxygen species production of eosinophils after stimulation with C5a, platelet-activating factor, and granulocyte-macrophage colony-stimulating factor. In summary, this study shows that the GPI-anchored antigen CD52 is not only a useful marker to distinguish eosinophils from neutrophils. The data point out a novel role of the CD52 antigen on human eosinophils that might be of clinical relevance, because cross-linking of this molecule will stop the destructive power of human eosinophils in the inflammatory tissue.

Human eotaxin represents a potent activator of the respiratory burst of human eosinophils.

Increased numbers of eosinophils are found in parasitic infections, autoimmune diseases and allergic diseases such as allergic asthma. They are activated by distinct cytokines and chemokines leading to the immigration in the inflamed tissue and mediate tissue damage by releasing reactive oxygen species. Here, the effect of the recently cloned CC chemokine human eotaxin was investigated for its ability to affect different eosinophil effector functions and compared to the CC chemokines MCP-3 and RANTES. Human eotaxin induced chemotaxis of human eosinophils in a dose-dependent manner. The range of efficacy of the CC chemokines compared to the well-known chemotaxin C5a was eotaxin = RANTES > MCP-3 = C5a. In addition, eotaxin induced rapid and transient actin polymerization, a prerequisite for cell migration, in eosinophils in the same range of efficacy as observed for chemotaxis. To investigate whether eotaxin was able to activate the respiratory burst of eosinophils, release of reactive oxygen species was measured by lucigenin-dependent chemiluminescence. Eotaxin induced production of significantly high amounts of reactive oxygen species at a concentration between 10 ng/ml and 500 ng/ml. Surprisingly, the effect of eotaxin was comparable to the well-known eosinophil activator C5a. The range of efficacy of the CC chemokines compared to C5a in the activation of the respiratory burst was eotaxin = C5a > MCP-3 > RANTES. Production of reactive oxygen species was inhibited by pertussis toxin, staurosporin, genestein and wortmannin. Furthermore, eotaxin induced transient increases in intracellular calcium concentration ([Ca2+]i) in human eosinophils. Therefore, pertussis toxin-sensitive Gi-proteins, protein kinase C, tyrosine kinase, phosphatidylinositol-3-kinase and transient increases in [Ca2+]i are involved in the signal transduction of eosinophils following stimulation with eotaxin. In summary, this study reveals the importance of the CC chemokine eotaxin as a potent activator of the respiratory burst, actin polymerization and chemotaxis. Eotaxin, therefore, plays an important role not only by attracting eosinophils to the site of inflammation but also by damaging tissue by its capacity to induce the release of reactive oxygen species.

[Evaluating polymerase chain reaction for detection of C. trachomatis in urogenital smears]. / Evaluierung der Polymerase-Kettenreaktion zum Nachweis von C. trachomatis aus urogenitalem Abstrichmaterial.

A total of 222 urogenital specimens were investigated with a commercially available polymerase chain reaction (Amplicor test) for the direct detection of Chlamydia trachomatis. The results were compared with those yielded by the conventional cell culture technique. Using cell culture a urogenital C. trachomatis infection could be detected in 72 of 222 patients. The Amplicor test yielded a positive result in 83. Referred to the detection rate of the Amplicor test and that of the cell culture, sensitivity was 91.2% for the test sensitivity and 79.1% for the cell culture. The specificity of both techniques was 100% when the specimens for which neither both nor either one of the tests gave positive results were considered. In accordance with other studies, this study suggests that tests based on nucleic acid amplification will supersede cell cultures as the gold standard for the detection of C. trachomatis and also become the method of choice in routine diagnosis of urogenital chamydial infections.

Large edentulous ridges--are they better for dentures than small ridges?

A method was described for measuring not only the area of the basal seat of an edentulous ridge but also the bearing area, stabilizing area, and the areas shared. A definition for small, medium, and large edentulous ridges was provided. Correlations between the basal seat, stabilizing area, and the shared areas were computed. A high positive correlation was found between the area of the basal seat and that of the stabilizing areas. Contrary to what was expected, no correlation was found between the area of the basal seat and that of the bearing areas of the small to large categories.