No abstract

Acute myeloid and lymphoblastic leukemia are poor prognosis hematologic malignancies, which disseminate from the bone marrow into the blood. Blast interactions with selectins expressed by vascular endothelium promote the development of drug resistance and leukostasis. While the role of selectins in initiating leukemia blast adhesion is established, our knowledge of the involved selectin ligands is incomplete. Using various primary acute leukemia cells and U937 monoblasts, we identified here functional selectin ligands expressed by myeloblasts and lymphoblasts by performing biochemical studies, expression inhibition by RNA interference and flow adhesion assays on recombinant selectins or selectin ligands immunoadsorbed from primary blast cells. Results demonstrate that P-selectin glycoprotein ligand-1 (PSGL-1) is the major P-selectin ligand on myeloblasts, while it is much less frequently expressed and used by lymphoblasts to interact with endothelial selectins. To roll on E-selectin, myeloblasts use PSGL-1, CD44, and CD43 to various extents and the contribution of these ligands varies strongly among patients. In contrast, the interactions of PSGL-1-deficient lymphoblasts with E-selectin are mainly supported by CD43 and/or CD44. By identifying key selectin ligands expressed by acute leukemia blasts, this study offers novel insight into their involvement in mediating acute leukemia cell adhesion with vascular endothelium and may identify novel therapeutic targets.

Patients in paediatric intensive care units (PICU) often receive numerous medications by the parenteral route. Frequently two or more drugs are delivered simultaneously through the same line and the risk of physicochemical incompatibilities is thus important. The objectives of this study were 1) to identify prospectively the combinations of injectable drugs administered in the PICU of our university hospital and 2) to analyze them according to information found in the literature. The data were collected by a pharmacist over a 30-day period and classified in three categories: compatible, incompatible and undocumented. Nineteen patients were included in the study with a median age of 3.2 years. The mean number (+/- SD) of injectable drugs per patient and per day was 6.5 (+/- 2.8), for a total of 26 drugs and 7 solutes. 64 combinations of drugs were observed with 2 (31.3%), 3 (45.3%), 4 (10.9%) or 5 (12.5%) drugs. 81 drug-drug and 94 drug-solute combinations were recorded. Among these, 151 (86.3%) were compatible, 6 (3.4%) incompatible and 18 (10.3%) undocumented. The incompatibilities included furosemide (Lasix), a drug in alkaline solution and Vamina-Glucose, a total parenteral nutrition solution. No clinical consequences resulting from drug incompatibilities were shown in this study. We suggest that in vitro compatibility tests on standard drug combinations, as well as a training program for nurses on drug incompatibility problems would sensitively increase the security of parenteral drug administration.