Search

Background: Flow cytometry is the most commonly used technology to measure microvesicles (MVs). Despite reported limitations of this technique, MV levels obtained using conventional flow cytometry have yielded many clinically relevant findings, such as associations with disease severity and ability to predict clinical outcomes. This study aims to determine if MV enumeration by flow cytometry correlates with a measurement of their functional capacity, as this may explain how flow cytometry generates clinically relevant results., Methods: ONE HUNDRED SAMPLES FROM HEALTHY INDIVIDUALS AND PATIENTS WITH OBSTRUCTIVE SLEEP APNOEA WERE ANALYSED BY CONVENTIONAL FLOW CYTOMETRY (FACSCALIBUR) AND BY THREE FUNCTIONAL MV ASSAYS: Zymuphen MP-activity in which data were given as phosphatidylserine equivalent, STA(®) Phospholipid Procoag Assay expressed as clotting time and Endogenous Thrombin Potential (ETP) reflecting in vitro thrombin generation. Correlations were determined by Spearman correlation., Results: Absolute counts of lactadherin+ procoagulant MVs generated by flow cytometry weakly correlated with the results obtained from the Zymuphen MP-activity (r=0.5370, p<0.0001); correlated with ETP (r=0.7444, p<0.0001); negatively correlated with STA(®) Phospholipid Procoag Assay clotting time (-0.7872, p<0.0001), reflecting a positive correlation between clotting activity and flow cytometry. Levels of Annexin V+ procoagulant and platelet-derived MVs were also associated with functional assays. Absolute counts of MVs derived from other cell types were not correlated with the functional results., Conclusions: Quantitative results of procoagulant and platelet-derived MVs from conventional flow cytometry are associated with the functional capability of the MVs, as defined by three functional MV assays. Flow cytometry is a valuable technique for the quantification of MVs from different cellular origins; however, a combination of several analytical techniques may give the most comprehensive information on the role of MVs in health and disease.

While the olfactory and tactile vibrissal systems have been extensively studied in the rat, the neural basis of these cross-modal associations is still elusive. Here we tested the hypothesis that the lateral entorhinal cortex (LEC) could be particularly involved. In order to tackle this question, we have developed a new behavioral paradigm which consists in finding one baited cup (+) among three, each of the cups presenting a different and specific odor/texture (OT) combination. During the acquisition of a first task (Task OT1), the three cups were associated with the following OT combination: O1T1 for the baited cup; O2T1 and O1T2 for non-baited ones. Most rats learn this task within three training sessions (20 trials/session). In a second task (Task OT2) animals had to pair another OT combination with the reward using a new set of stimuli (O3T3+, O4T3, and O3T4). Results showed that rats manage to learn Task OT2 within one session only. In a third task (Task OT3) animals had to learn another OT combination based on previously learned items (e.g. O4T4+, O1T4 and O4T1). This task is called the "recombination task." Results showed that control rats solve the recombination task within one session. Animals bilaterally implanted with cannulae in the LEC were microinfused with d-APV (3 µg/0.6 µL) just before the acquisition or the test session of each task. The results showed that NMDA receptor blockade in LEC did not affect recall of Task OT1 but strongly impaired acquisition of both Task OT2 and OT3. Moreover, two control groups of animals infused with d-APV showed no deficit in the acquisition of unimodal olfactory and tactile tasks. Taken together, these data show that the NMDA system in the LEC is involved in the acquisition of association between an olfactory and a tactile stimulus during cross-modal learning task., (© 2014 Wiley Periodicals, Inc.)