Morio Aihara

Effect of fibronectin and von Willebrand factor on the adhesion of human fixed washed platelets to collagen immobilized beads

The adhesion of human fixed washed platelets (FWP) to collagen was measured using collagen immobilized beads. The addition of normal plasma or severe von Willebrand disease (VWD) plasma to FWP decreased the adhesion, suggesting the presence of some inhibitors of platelet adhesion in human plasma. Although the adhesion of FWP in severe VWD plasma was not different from that of FWP in normal plasma, the addition of purified von Willebrand factor (vWF, 1-2 mu/ml ristocetin cofactor) to FWP in buffer increased the FWP adhesion at higher flow rates, and the percent of adhesion in the absence of vWF was 10% (collagen 500 micrograms) and 30% (collagen 1,000 micrograms) of that in the presence of vWF at 10 ml/min. The enhancing effect of the vWF on FWP adhesion was also observed by pretreatment of the collagen column with vWF suggesting the important role of bound vWF to the collagen; adhesion 72% to the collagen column (1,600 micrograms) treated with vWF and 16% to the collagen column without the pretreatment at 10 ml/min. The promoting effect of vWF was also present in some commercial factor VIII preparations which had no large or intermediate multimers of vWF antigen. The adhesion of FWP was inhibited by fibronectin (FN) and the binding of ristocetin cofactor (vWF:RCo) to collagen fiber was also inhibited by FN; bound vWF:RCo to 50 micrograms/ml collagen in the absence or presence of 125 micrograms/ml FN were 60% and 8% respectively. It is suggested that vWF, even small multimer of vWF:Ag, is involved in the initial platelet-collagen interaction at high flow rates, while plasma FN acts as one of anti-adhesion factor.

Head-to-head comparison of procalcitonin and presepsin for the diagnosis of sepsis in critically ill adult patients: a protocol for a systematic review and meta-analysis

Introduction Early diagnosis and immediate therapeutic intervention, including appropriate antibiotic therapy and goal-directed resuscitation, are necessary to reduce mortality in patients with sepsis. However, a single clinical or biological marker indicative of sepsis has not been adopted unanimously. Although procalcitonin and presepsin are promising biomarkers that can effectively differentiate between sepsis/infection and systemic inflammatory response syndrome of non-infectious origin, little is known about which marker is superior. Methods and analysis We will conduct a systematic review and meta-analysis of procalcitonin and presepsin for the diagnosis of sepsis/infection in critically ill adult patients. The primary objective is to evaluate the diagnostic accuracy of these 2 biomarkers to a reference standard of sepsis/infection and to compare the diagnostic accuracy with each other. We will search electronic bibliographic databases such as MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials for retrospective and prospective diagnostic test studies. We will assign 2 reviewers to review all collected titles and associated abstracts, review full articles, and extract study data. We will use the Quality of Diagnostic Accuracy Studies-II tool to report study characteristics and to evaluate methodological quality. If pooling is possible, we will use bivariate random effects and hierarchical summary receiver operating characteristic (ROC) models to calculate parameter estimates to output summary ROCs, pooled sensitivity and specificity data, and 95% CIs around the summary operating point. We will also assess heterogeneity via clinical and methodological subgroup and sensitivity analyses. Ethics and dissemination This systematic review will provide guidance on the triage of these tests, help to determine whether existing tests should be revised or replaced, and may also identify knowledge gaps in sepsis diagnosis that could direct further research in the field. Research ethics is not required for this review. The findings will be reported at conferences and in peer-reviewed publications. Trial registration number CRD42016035784.