Human vascular endothelial cells express a membrane protein complex immunochemically indistinguishable from the platelet VLA-2 (glycoprotein Ia-IIa) complex

Endothelial cells express surface molecules that are involved in cell- matrix interaction, including the vitronectin receptor and the fibronectin receptor, both members of a family of cell adhesion receptors (integrins). Here we provide evidence that endothelial cells express a membrane molecule, indistinguishable from the platelet VLA-2 complex, which is a collagen receptor and a member of the integrin family. To identify this endothelial molecule, we have used a monoclonal antibody, CLB-10G11, which recognizes the VLA-2 complex from platelets. The molecule recognized by CLB-10G11 from endothelial cells was characterized as follows. (1) The monoclonal antibody precipitated two proteins from surface-labeled endothelial cells that corresponded to the platelet VLA-2 subunits (glycoprotein Ia and IIa) as judged by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional nonreduced/reduced SDS- PAGE. (2) Preclearing of endothelial cells with monoclonal antibody A- 1A5, an antibody that is directed against the common VLA beta subunit, removed all the CLB-10G11-binding material. (3) Crossed immunoelectrophoresis revealed that CLB-10G11 recognizes a single precipitation arc from either platelets or endothelial cells. Analysis of these two cell types in one gel again revealed one precipitation arc. The antigen of either cell type, recognized by CLB-10G11 could be precipitated by either polyclonal antiplatelet or polyclonal antiendothelial cell antiserum. Hence, it appears that endothelial cells express at least three different surface molecules (the vitronectin receptor, the fibronectin receptor and a collagen receptor), which may play an important role in controlling the anchorage of endothelial cells to the extracellular matrix.     

Antibody ligation of CD9 modifies production of myeloid cells in long- term cultures

The KMC8.8 monoclonal antibody was made by immunizing rats with the BMS2 stromal cell clone, and was selected for further study because its ability to inhibit production of myeloid cells in Dexter cultures but not that of lymphoid cells in Whitlock-Witte cultures. The influence on myeloid progenitors might have been indirect, since the antibody did not prevent responsiveness to colony-stimulating factors in semisolid agar cultures. Furthermore, there was no inhibition, and some augmentation, of cell production when the antibody was added to established Dexter cultures. A cDNA clone that encoded the KMC8.8- recognized molecule was isolated by expression cloning and found to be identical in sequence to a previously published murine CD9 homologue. The antibody and cDNA clone were used to establish that CD9 is expressed by stromal cells, megakaryocytes, platelets, myeloid cells, and subpopulations of mature lymphocytes in mice. Treatment with the KMC8.8/CD9 antibody slightly augmented adhesion between myeloid cells and stromal cells, consistent with previous reports that this member of the tetraspan family of proteins can transmit proadhesive signals to human platelets and lymphoid cells. CD9 might participate in cell-cell interactions critical for correct orientation and movement of maturing myeloid cells in bone marrow.     

A comparison of tele-education versus conventional lectures in wound care knowledge and skill acquisition

We conducted a randomized controlled study to compare conventional lectures with tele-education for delivering wound care education. Education was delivered by the two methods simultaneously to two classes. Forty-eight paramedics received a live didactic presentation and 41 paramedics received the same lecture via videoconferencing. The participants were evaluated by a multiple-choice examination and a practical test of their wound closure skills. There were no significant differences in any category of the practical skills test, and no difference in the results of the written examination: the mean total score was was 109.0 (95% CI 105.7-112.4) in the conventional lecture group and 110.3 (95% CI 106.2-114.3) in the video group (P = 0.63). In a survey at the end of the study the live lecture group rated the overall effectiveness of teaching significantly higher than the video-based group: the median scores for effectiveness of teaching were 6.0 (IQR 5.5-6.0) in the live lecture group and 4.0 (IQR 3.0-5.0) in the video group (P < 0.001). Videoconferencing was at least as effective as live didactic presentation.     

DOES THE METHOD OF TRANSLUMINAL CORONARY REVASCULARISATION INFLUENCE RE-STENOSIS? BALLOON ANGIOPLASTY,ATHERECTOMY AND STENTS COMPARED

SUMMARY Luminal renarrowing after successful coronary angioplasty is now recognised as a continuously distributed process which is determined largely by the extent of luminal increase achieved at angioplasty. In this study an alternative analytical approach is applied to determine whether luminal renarrowing following coronary intervention is related to the mechanism of luminal increase (ie by balloon, by atherectomy, by a self-expanding stainless steel mesh stent, or by a balloon-expandable tantalum coil stent). The results confirm the known proportional relationship between luminal renarrowing during follow-up and luminal improvement at intervention, regardless of the device used. However, significant differences were observed between the devices, which may reflect device-specific characteristics of the hyperplastic response to vessel injury and may have clinical implications.