| 1. |
- Mazzucato, M, et al.
(author)
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Vascular PG-M/versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation
- 2002
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In: FASEB Journal. - 1530-6860. ; 16:14, s. 1903-1916
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Journal article (peer-reviewed)abstract
- We have identified a novel von Willebrand factor/fibrinogen/selectin-independent, platelet adhesion-promoting function of vascular PG-M/versicans that may be relevant in normal venous thrombosis and critical in atherosclerotic conditions. A purification scheme was devised to obtain vascular versicans, which by biochemical, immunochemical, and ultrastructural means were asserted to be 1) composed primarily of isoforms V1 and V2; 2) free of contaminants; 3) prevalently substituted with chondroitin-4-sulfate and dermatan sulfate (DS) chains; and 4) capable of binding hyaluronan to form link protein-stabilized ternary complexes. Real-time analysis of human platelet perfused under diverse shear forces showed that they largely failed to bind to several vascular and nonvascular proteoglycans (PGs). In contrast, they bound in a dose- and shear rate-dependent manner to vascular versicans, exhibiting a unique attachment-detachment kinetics and establishing a firm substrate tethering characterized with no significant aggregation. Digestion of these PGs with lyases and competition experiments with purified glycosaminoglycans revealed that platelet adhesion to vascular versicans was primarily mediated by their DS chains. Incorporation of the versicans into fibrillar collagen substrates augmented their adhesive activity and strongly promoted platelet aggregation at low and high shear rates. Affinity chromatography of platelet surfaces on DS columns identified a 120-140 kDa polypeptide complex that behaved as a specific vascular versican binding membrane ligand in solid-phase binding assays. These findings indicate that selective versican variants of the subendothelium may serve as ancillary GPIbalpha/integrin/selectin-independent platelet ligands in healthy and diseased vascular beds and may be directly responsible for the platelet accruing after rupture of atherosclerotic plaques., versican variants promote platelet adhesion at low shear rates and cooperate with collagens to induce aggregation.
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| 2. |
- Perissinotto, D, et al.
(author)
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Avian neural crest cell migration is diversely regulated by the two major hyaluronan-binding proteoglycans PG-M/versican and aggrecan
- 2000
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In: Development: For advances in developmental biology and stem cells. - 1477-9129. ; 127:13, s. 2823-2842
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Journal article (peer-reviewed)abstract
- It has been proposed that hyaluronan-binding proteoglycans play an important role as guiding cues during neural crest (NC) cell migration, but their precise function has not been elucidated. In this study, we examine the distribution, structure and putative role of the two major hyaluronan-binding proteoglycans, PG-M/versicans and aggrecan, during the course of avian NC development. PG-M/versicans V0 and V1 are shown to be the prevalent isoforms at initial and advanced phases of NC cell movement, whereas the V2 and V3 transcripts are first detected following gangliogenesis. During NC cell dispersion, mRNAs for PG-M/versicans V0/V1 are transcribed by tissues lining the NC migratory pathways, as well as by tissues delimiting nonpermissive areas. Immunohistochemistry confirm the deposition of the macromolecules in these regions and highlight regional differences in the density of these proteoglycans. PG-M/versicans assembled within the sclerotome rearrange from an initially uniform distribution to a preferentially caudal localization, both at the mRNA and protein level. This reorganization is a direct consequence of the metameric NC cell migration through the rostral portion of the somites. As suggested by previous in situ hybridizations, aggrecan shows a virtually opposite distribution to PG-M/versicans being confined to the perinotochordal ECM and extending dorsolaterally in a segmentally organized manner eventually to the entire spinal cord at axial levels interspacing the ganglia. PG-M/versicans purified from the NC migratory routes are highly polydispersed, have an apparent M(r) of 1,200-2,000 kDa, are primarily substituted with chondroitin-6-sulfates and, upon chondroitinase ABC digestion, are found to be composed of core proteins with apparent M(r )of 360-530, 000. TEM/rotary shadowing analysis of the isolated PG-M/versicans confirmed that they exhibit the characteristic bi-globular shape, have core proteins with sizes predicted for the V0/V1 isoforms and carry relatively few extended glycosaminoglycan chains. Orthotopical implantation of PG-M/versicans immobilized onto transplantable micromembranes tend to 'attract' moving cells toward them, whereas similar implantations of a notochordal type-aggrecan retain both single and cohorts of moving NC cells in close proximity of the implant and thereby perturb their spatiotemporal migratory pattern. NC cells fail to migrate through three-dimensional collagen type I-aggrecan substrata in vitro, but locomote in a haptotactic manner through collagen type I-PG-M/versican V0 substrata via engagement of HNK-1 antigen-bearing cell surface components. The present data suggest that PG-M/versicans and notochordal aggrecan exert divergent guiding functions during NC cell dispersion, which are mediated by both their core proteins and glycosaminoglycan side chains and may involve 'haptotactic-like' motility phenomena. Whereas aggrecan defines strictly impenetrable embryonic areas, PG-M/versicans are central components of the NC migratory pathways favoring the directed movement of the cells.
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| 3. |
- Perris, C, et al.
(author)
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Assessment of dysfunctional working models of self and others in schizophrenic patients : a summary of data collected in nine nations. International Research Group.
- 2000
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In: Acta Psychiatrica Scandinavica. - 0001-690X .- 1600-0447. ; 102:5, s. 336-41
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate the cross-cultural feasibility of a new scale for assessing dysfunctional working models of self and others, and to evaluate its discriminative power.METHOD: Schizophrenic patients (N=351), non-psychotic patients (N= 86) and non-clinical subjects (N= 511) collected in 10 centres completed the DWM-S. Current psychopathology was assessed by means of the BPRS.RESULTS: Alpha coefficients were high in all samples. Mean scores on the DWM-S appeared to be comparable in all countries, suggesting cross-national generalizability. No significant correlation was found with sex, age, levels of psychopathology and duration of illness. Discriminant analyses showed that more than 70% of the schizophrenic patients are correctly classified.CONCLUSION: The DWM-S is an easily administered self-report instrument which allows to pinpoint internal dysfunctional working models of self and others in various types of patients. It is a useful tool for case conceptualization, especially when psychotherapeutic interventions are part of the treatment programme.
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| 4. |
- Cattaruzza, S, et al.
(author)
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Distribution of PG-M/versican variants in human tissues and de novo expression of isoform V3 upon endothelial cell activation, migration, and neoangiogenesis in vitro
- 2002
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In: Journal of Biological Chemistry. - 1083-351X. ; 277:49, s. 47626-47635
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Journal article (peer-reviewed)abstract
- We have carried out a comprehensive molecular mapping of PG-M/versican isoforms V0-V3 in adult human tissues and have specifically investigated how the expression of these isoforms is regulated in endothelial cells in vitro. A survey of 21 representative tissues highlighted a prevalence of V1 mRNA, demonstrated that the relative frequency of expression was V1>V2>V3greater than or equal toV2; and showed that <15% of the tissues transcribed significant levels of all four isoforms. By employing novel and previously described anti-versican antibodies we verified a ubiquitous versican deposition in normal and tumor-associated vascular structures and disclosed differences in the glycanation profiles of versicans produced in different vascular beds. Resting endothelial cells isolated from different tissue sources transcribed several of the versican isoforms but consistently failed to translate these mRNAs into detectable proteoglycans. However, if stimulated with tumor necrosis factor-α or vascular endothelial growth factor, they altered their versican expression by de novo transcribing the V3 isoform and by exhibiting a moderate V1/V2 production. Induced versican synthesis and de novo V3 expression was also observed in endothelial cells elicited to migrate in a wound-healing model in vitro and in angiogenic endothelial cells forming tubule-like structures in Matrigel or fibrin clots. The results suggest that, independent of the degree of vascularization, human adult tissues show a limited expression of versican isoforms V0, V2, and V3 and that endothelial cells may contribute to the deposition of versican in vascular structures, but only following proper stimulation.
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| 5. |
- Di Cesare, PE, et al.
(author)
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Matrix-matrix interaction of cartilage oligomeric matrix protein and fibronectin
- 2002
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In: Matrix Biology. - 1569-1802. ; 21:5, s. 461-470
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Journal article (peer-reviewed)abstract
- Recent work indicates that cartilage oligomeric matrix protein (COMP) plays an important role in extracellular matrix assembly and matrix-matrix protein interactions. In order to identify the proteins in extracellular matrix that interact with COMP, we used an ELISA-based solid-phase binding assay, which revealed a specific, high-affinity interaction between COMP and fibronectin. This interaction is concentration-dependent and saturable, and appears to occur under physiologically relevant conditions. Electron microscopy after negative staining and fragment binding analysis using the solid-phase assay revealed a predominant binding site for the COMP C-terminal globular domain to a molecular domain approximately 14 nm from the N-terminal domain of fibronectin, which can be inhibited by the presence of a polyclonal antibody specific for the C-terminal heptadecapeptide of COMP This interaction is further demonstrated in vivo by colocalization of both COMP and fibronectin in the chondrocyte pericellular matrix by laser confocal microscopy of chondrocytes grown in agarose culture, and by appositional and colocalization of these proteins in the growth plate of primates by immunohistochemistry. (C) 2002 Elsevier Science B.V./International Society of Matrix Biology. Published by Elsevier Science B.V. All rights reserved.
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