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Monocyte Response (monocyte + response)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Dysregulation of monocyte oxidative burst in streptococcal endocarditis

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2001
E. Presterl
Background Streptococcal subacute endocarditis is characterized by low-grade systemic inflammation. Although structural cardiac defects are pivotal, phagocytic cells, i.e. monocytes and neutrophils, are involved in the induction and the course of bacterial endocarditis. Decreased production of reactive oxygen metabolites was described in long-lasting infections. We hypothesized that the oxidative burst of phagocytes induced by the infecting organism is defective in patients with streptococcal endocarditis. Patients and methods The monocytes and neutrophils of 11 patients with streptococcal native valve endocarditis were challenged with the respective pathogens and two control streptococcal strains, and the oxidative burst was determined by fluorescence-activated cell sorter analysis. These experiments were done before any antibiotic therapy was administered, and repeated at least 12 months after recovery. Eight volunteers served as healthy controls. Results The monocyte response to the respective pathogens was decreased in the patient groups compared to the response to the control streptococci. After cure the monocyte response to the pathogens was not different to the response to the control strains. The monocyte response of the healthy volunteers did not show any differences between the patients' pathogens and the control strains. The neutrophil oxidative burst to the pathogens was similar to that to the control streptococci in both patient and the volunteer group. Conclusion The decreased response of patient monocytes to the pathogens may contribute to the low-grade inflammatory response and to the course of streptococcal endocarditis. [source]

Human monocyte response to retrieved polymethylmethacrylate particles

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 3 2002
Masatsugu Miyaguchi
Abstract The purpose of this study was to compare retrieved polymethylmethacrylate (PMMA) particles from failed total hip arthroplasties in terms of size, shape, and the response of human monocytes with commercially available particles. PMMA particles were isolated from peri-implant tissues of five failed cemented total hip arthroplasties using tissue digestion and a sucrose density gradient technique. Prepolymerized cement powder and those from which barium sulfate had been removed were examined for comparison. After exposure of peripheral human monocytes to PMMA particles, tumor necrosis factor-, and interleukin-6 in medium were measured by using enzyme-linked immunosorbent assays. Image analysis revealed that retrieved particles were larger (retrieved: 1.24 ,m; prepolymerized cement powder: 0.83 ,m; barium sulfate-free powder: 0.87 ,m) and were more irregular in shape and rougher than commercially available particles. Cytokine release was increased by all PMMA particle species. However, commercially available PMMA particles stimulated the release of necrosis factor-, and interleukin-6 more strongly than did retrieved particles at very high doses. The observed difference in monocyte response might be due to the volume of the challenged particles. Another possible reason for the difference might be alteration of the surface chemistry of particles in situ and the difference in surface morphology between them. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 331,337, 2002 [source]

Developing Ovarian Follicles Inhibit the Endotoxin-Induced Glomerular Inflammatory Reaction in Pseudopregnant Rats

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2004
Marijke M. Faas
Problem:, We tested the hypothesis that developing ovarian follicles produce factors inhibiting the endotoxin induced inflammatory response. Method of study:, Pseudopregnant rats were treated with FSH to induced follicular development (FSH-rats). For control we used untreated pseudopregnant rats (PSP-rats) and rats in the follicular phase of the ovarian cycle (C-rats). All rats were infused with either saline or endotoxin. Three days after the infusion rats were sacrificed and kidney specimens were snapfrozen. Cryostat kidney sections were stained for the presence of monocytes, granulocytes, CD11a- and CD11b-positive cells and for ICAM-1 expression. Results:, The results show that induction of follicular development in pseudopregnant rats inhibited glomerular infiltration of monocytes and CD11b+ cells, while it did not affect the other parameters, i.e. glomerular granulocyte number, CD11a+ cells and glomerular ICAM-1 expression. Conclusion:, Developing ovarian follicles produce factors inhibiting monocyte responses to endotoxin. [source]