#ACTIVATE NEURO PROGRAMMER 2 REVIEW SERIES#

This assay reflects the tendency of activated platelets to form micro-aggregates in circulation. Platelet aggregates (PAg)Д¬irculating PAg were measured by flow cytometry, as described. Particle counts measured in 1-minute runs were converted to concentrations in plasma based on the dilution factor and rate of flow through the cytometer, as detailed. Results are expressed as PMP Г— 10 7/ОјL plasma. Events were detected and counted by triggering on the fluorescent signal. fixation, 2.0 mL of PBS was added and PMP were measured by flow cytometry with the neutral density filter removed. Five ОјL of fluorescein isothiocyanate (FITC)-conjugated anti-CD41 was added to 20 ОјL of PPP, and after 20 min., 25 ОјL of 4% PFA fixative also added. Platelet-poor plasma (PPP) was then prepared by centrifuging PRP for 6 min. Briefly, platelet-rich plasma (PRP) was prepared by centrifuging whole blood 10 min. Normal ranges of values were used for reference. Platelet counts and plasma protein S activities were carried out by the clinical pathology laboratories, University of Miami. Although drawing into Vacutainers induces slight platelet activation compared to the syringe method, they were required by the phlebotomy clinic, and normal controls were drawn in the same way. Samples were prepared for flow cytometry not more than 2 hours after phlebotomy. The first tube drawn was not used for platelet studies to avoid platelet activation from thromboplastin released by the puncture wound. After blood flow was established, the tourniquet was promptly removed to minimize artifactual platelet activation. Blood samplingДЄ 4.5 mL blood sample was drawn into Vacutainer В® tubes containing citrate, using a 21-gauge butterfly needle following light application of a tourniquet. The study protocol was approved by the IRB office of University of Miami and signed informed consents were obtained. Thirty-three treatment-naГЇve, clinically stable relapsing-remitting MS patients and 92 normal control subjects were recruited. For this study, we employed consecutively recruited patients and measured, in addition to routine tests such as platelet counts, the expression of platelet activation marker P-selectin (CD62p), platelet microparticles (PMP) in plasma, platelet micro-aggregates (PAg), protein S activity, and platelet-associated immunoglobulins IgG and IgM, as described following.

To investigate the basis of these observations, we have applied the flow cytometric analysis of platelet-derived microparticles (PMP) and CD62p expression, as well as other more conventional assays. Our observation of platelet abnormalities in MS and subsequent observation of thrombosis in cutaneous venules and capillaries adjacent to subcutaneous ulcers complicating subcutaneous injections of interferon-beta1b heightened our interest in a possible role of platelet dysfunction in MS. More recently, a central role for platelets in inflammation has emerged, as reviewed. Although other investigations confirmed their findings, they contributed little additional information. The investigators reported increased platelet adhesiveness in both MS and Guillain-Barre correlating with disease activity. For example, Nathanson and Savitsky employed a measure of platelet adhesiveness in 132 subjects, 60 of whom had MS.

#ACTIVATE NEURO PROGRAMMER 2 REVIEW SERIES#

Although Putnam investigated a possible role of venule thrombosis as a factor in central nervous system (CNS) demyelination in 1935, a role for platelets in CNS demyelination was not further considered until a series of papers in the 1960s, such as that of Wright et al. The fatal outcome in one of two multiple sclerosis (MS) patients with idiopathic thrombocytopenic purpura (ITP) prompted our interest in platelet activity and function in the context of MS. Additional study of platelet activation and function in MS patients is warranted. The mechanisms underlying this activation and its significance to MS are unknown. Platelets are significantly activated in MS patients. Protein S in MS patients did not differ significantly from normal values. Platelet-associated IgM, but not IgG, was marginally elevated in MS (p = 0.01).

ResultsД¬ompared to controls, PMP were significantly elevated in MS (p < 0.001) and CD62p expression was also markedly elevated (p < 0.001).

In addition, plasma protein S activity was measured. Platelet counts, measures of platelet activation, as well as platelet-associated IgG/IgM, were carried out. In this report, 92 normal controls and 33 stable, untreated MS patients were studied. Previously, we presented evidence of platelet activation in a small cohort of treatment-naive MS patients. A fatality in one multiple sclerosis (MS) patient due to acute idiopathic thrombocytopenic purpura (ITP) and a near fatality in another stimulated our interest in platelet function abnormalities in MS.

Activate neuro programmer 2 review