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Little is known about the biochemical "machinery" responsible for the morphological features of apoptosis, although the cytoskeleton is presumed to be involved. Using flow cytometry, polyacrylamide gel electrophoresis, and fluorescence microscopy, we show that apoptosis induced by ultraviolet (UV) irradiation or 80 micrograms/ml etoposide correlates with early transient polymerization and later depolymerization of filamentous (F)-actin and dramatic changes in visible microfilament organization. Depolymerization of F-actin began before the formation of apoptotic bodies and was ultimately composed of decreases in both the detergent-insoluble (40%) and detergent-soluble (50%) pools of F-actin. Dihydrocytochalasin B (H2CB), which blocked apoptotic body formation, depolymerized F-actin in the detergent-insoluble pool only. Visually, H2CB treatment disrupted microfilament organization, resulting in short, brightly stained microfilaments dispersed throughout the cytoplasm. In contrast, apoptotic cells contained a network of fine microfilaments with bright staining concentrated at the site of apoptotic body formation. Together, these results suggest that reorganization of the microfilament network is necessary for the formation of apoptotic bodies and that depolymerization of F-actin may also be a necessary component of the process of apoptosis.

AP in humans is characterized by significant reduction of peripheral blood T- and B-lymphocytes.

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PAH is characterised by upregulated tryptophan metabolism and enhanced biosynthesis of kynurenine. Elevated kynurenine concentration is associated with an adverse clinical course. Dysregulated immunity, delineated by Treg-Th17 imbalance, is directly related to diverse activation of the kynurenine pathway, indicating the potential interplay between kynurenines and the immune system in PAH.

We investigated whether the choice of anticoagulant or the application of density gradient mononuclear cell isolation may account for conflicting published data regarding the levels of the scavenger receptors' expression in healthy individuals. We demonstrate that the detection of CD163, but not CD36, differs dramatically among the methods.CD163 is a member of the scavenger receptor cysteine-rich family of proteins, accounting for the clearance of hemoglobinhaptoglobin complexes, which in turn fuel an anti-inflammatory response mediated by heme metabolites (6, 10). CD163 is also an attractive candidate for potential diagnostic use as a marker of monocyte/macrophage activity in inflammatory diseases (1,3,8,11). However, it is still unclear how many circulating monocytes in normal subjects express the CD163 molecule on their surface. Previous studies with Mac 2-48, RM3/1, Ber-Mac3, and other monoclonal antibodies indicated that 0 to 100% of CD14 ϩ monocytes were positive for CD163, as detected by flow cytometry (2,4,11,12,13). Possibly due to different protocols used for CD163 identification in various studies, some discrepancies were found even when the same clone of monoclonal antibody was used for different studies.In the current study, we analyzed the influence of three commonly used anticoagulants and mononuclear cell isolation on the level of CD163 expression evaluated with the use of commercially available, fluorochrome-conjugated GHI/61 monoclonal antibody. For comparison, the same kind of analysis was performed for another scavenger receptor, CD36, which is also expressed on monocytes and is involved mainly in phagocytosis of apoptotic neutrophils and uptake of modified low-density lipoproteins.Forty-eight individuals (20 female and 28 male) had blood drawn between 7 and 9 a.m. The donors were healthy volunteers aged 18 to 56 years and selected in accordance with the guidelines of the Bialystok Local Ethics Committee (no. 8-I-003/132/2004). Blood samples were divided into tubes with EDTA, citrate, or heparin and immediately processed.Whole-blood samples were incubated with CD14 fluorescein isothiocyanate (clone MP9), CD163 phycoerythrin (clone GHI/61), CD36 allophycocyanin (clone CB38) (all obtained from Becton Dickinson, San Jose, CA), and fluorochromeconjugated isotype controls for 30 min at room temperature. Red blood cells were lysed for 10 min with fluorescence-activated cell sorter lysing solution (Becton Dickinson, San Jose, CA). The remaining white blood cells were washed twice with phosphate-buffered saline and fixed with 400 l of 2% paraformaldehyde (5).Portions of each whole-blood sample were also used for isolation of mononuclear cells. Mononuclear cells were isolated using Histopaque (density, 1.077 g/ml; Sigma-Aldrich) density gradient centrifugation as described previously (9). The isolated cells were washed twice with phosphate-buffered saline, and the cell concentration was adjusted to 1 ϫ 10 6 cells/ ml. Mononuclear cells were stained with 20 l of fluorochrome-conjugated monoclonal antib...

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