For the identification of yeast genes specifying biochemical activities, a genomic strategy that is rapid, sensitive, and widely applicable was developed with an array of 6144 individual yeast strains, each containing a different yeast open reading frame (ORF) fused to glutathione S-transferase (GST). For the identification of ORF-associated activities, strains were grown in defined pools, and GST-ORFs were purified. Then, pools were assayed for activities, and active pools were deconvoluted to identify the source strains. Three previously unknown ORF-associated activities were identified with this strategy: a cyclic phosphodiesterase that acts on adenosine diphosphate-ribose 1"-2" cyclic phosphate (Appr>p), an Appr-1"-p-processing activity, and a cytochrome c methyltransferase.
Objective Children undergoing cardiac surgery with cardiopulmonary bypass (CPB) are susceptible to additional inflammatory and immunogenic insults from blood transfusions. We hypothesize that washing red blood cells (RBC) and platelets transfused to these patients will reduce post-operative transfusion-related immune modulation and inflammation. Design Prospective randomized controlled clinical trial. Setting University hospital pediatric cardiac intensive care unit. Patients Children from birth to 17 years old undergoing cardiac surgery with CPB. Interventions Children were randomized to an unwashed or washed RBC and platelet transfusion protocol for their surgery and postoperative care. All blood was leukoreduced, irradiated, and ABO identical. Plasma was obtained for laboratory analysis: pre-op, immediately, six and 12 hours after CPB. Primary outcome was the 12-hour post-CPB interleukin (IL)-6: IL-10 ratio. Secondary measures were IL levels, C-reactive protein (CRP), and clinical outcomes. Measurements and main results 162 subjects were studied, 81 per group. 34 subjects (17 per group) did not receive any blood transfusions. Storage duration of blood products was similar between groups. Among transfused subjects, the 12-hour IL ratio was significantly lower in the washed group (3.8 v. 4.8; p=0.04) secondary to lower IL-6 levels (post-CPB: 65 v.100 pg/ml; p = 0.06; 6 hour: 89 v.152 pg/ml; p = 0.02; 12-hour: 84 v.122 pg/ml; p = 0.09). Post-operative CRP was lower in subjects receiving washed blood (38 v. 43 mg/L; p = 0.03). There was a numerical, but not statistically significant decrease in total blood product transfusions (203 v. 260) and mortality (2 v. 6 deaths) in the washed group compared to the unwashed group. Conclusions Washed blood transfusions in cardiac surgery reduced inflammatory biomarkers, number of transfusions, donor exposures, and were associated with a non-significant trend towards reduced mortality. A larger study powered to test for clinical outcomes is needed to determine whether these laboratory findings are clinically significant.
To cite this article: Kaufman J, Spinelli SL, Schultz E, Blumberg N, Phipps RP. Release of biologically active CD154 during collection and storage of platelet concentrates prepared for transfusion. J Thromb Haemost 2007; 5; 788-96.Summary. Background: Millions of platelet transfusions are given each year. Transfusion reactions occur in as many as 30% of patients receiving unmodified platelet transfusions. The cause of some transfusion reactions remains unclear. The current paradigm suggests that platelet concentrates (PC) contain proinflammatory mediators that are released by white blood cells during collection, processing and storage. CD154 (CD40 ligand, CD40L) is a potent inflammatory mediator, normally sequestered inside the resting platelet, that is known to translocate to the platelet membrane and be shed into plasma in response to agonist activation. We hypothesized that plateletsoluble CD154 (sCD154) is ÔspontaneouslyÕ released by transfused platelets and plays a major role in transfusion reactions. Objectives: To determine the time course and biological properties of CD154 translocation and release during collection and storage of platelets for transfusion. Methods: We measured surface and sCD154 in platelets prepared by the platelet-rich plasma method or apheresis by fluorescence-activated cell sorting and enzyme-linked immunosorbent assay, respectively. The specific biological activity of platelet sCD154 was assayed by stimulation of the CD154/CD40 pathway in known CD40-positive cells with PC-derived supernatants. Results and conclusions: We demonstrate that PCs prepared for transfusion have high levels of membrane-bound CD154 and sCD154, with maximum levels being seen 72 h after platelet collection. Importantly, we show that platelet-derived sCD154 potently stimulates CD40-positive cells. We propose that plateletderived CD154 is a key ÔcytokineÕ responsible for adverse reactions associated with platelet transfusions. Improved methods of platelet collection and/or storage, which limit CD154 expression, could reduce the risks of transfusion reaction.
Objective-To investigate the presence and role of NF-B proteins in megakaryocytes and platelets. The nuclear factor-B (NF-B) transcription factor family is well known for its role in eliciting inflammation and promoting cell survival. We discovered that human megakaryocytes and platelets express the majority of NF-B family members, including the regulatory inhibitor-B (I-B) and I-kinase (
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