Assessment of platelet function in patients with stroke using multiple electrode platelet aggregometry: a prospective observational study

Background There is a link between high on-treatment platelet reactivity (HPR) and adverse vascular events in stroke. This study aimed to compare multiple electrode platelet aggregometry (MEA), in healthy subjects and ischaemic stroke patients, and between patients naive to antiplatelet drugs (AP) and those on regular low dose AP. We also aimed to determine prevalence of HPR at baseline and at 3–5 days after loading doses of aspirin. Methods Patients with first ever ischaemic stroke were age and sex-matched to a healthy control group. Three venous blood samples were collected: on admission before any treatment given (baseline); at 24 h and 3–5 days after standard treatment. MEA was determined using a Mutliplate® analyser and agonists tested were arachidonic acid (ASPI), adenosine diphosphate (ADP) and collagen (COL). Results Seventy patients (mean age 73 years [SD 13]; 42 men, 28 women) were age and sex-matched to 72 healthy subjects. Thirty-three patients were on antiplatelet drugs (AP) prior to stroke onset and 37 were AP-naive. MEA results for all agonists were significantly increased in AP-naive patients compared to healthy subjects: ADP 98 ± 31 vs 81 ± 24, p < 0.005; ASPI 117 ± 31 vs 98 ± 27, p < 0.005; COL 100 ± 25 vs 82 ± 20, p < 0.005. For patients on long term AP, 33% (10/30) of patients were considered aspirin-resistant. At 3–5 days following loading doses of aspirin, only 11.1% were aspirin resistant based on an ASPI cut-off value of 40 AU*min. Conclusions Many patients receiving low dose aspirin met the criteria of aspirin resistance but this was much lower at 3–5 days following loading doses of aspirin. Future studies are needed to establish the causes of HPR and potential benefits of individualizing AP treatment based on platelet function testing

The Carbon Cycle Influence on Tornadoes

The study of tornadogenesis inside the planetary boundary layer has become a primary focus of tornado studies in the past few years given the unpredictability of turbulence and many questions in this region still left unresolved. Given this limitation in computational fluid dynamics, the demand to work around it is paramount to understanding the role of the carbon cycle input to surface air properties and to create greater severe storm warning accuracy. The Bluewater simulations brought a new perspective to tornadogenesis, greatly opening the study potential into the surface properties that interact to generate such an awesome phenomenon of force. Plant photosynthesis contributes significant energy into the atmosphere. C3 and C4 plant types display a distinct regulation of tornadic potential as the variation of U.S. seasonal shifts and land cover types display unique relations to both photosynthesis processes and tornadic formation. The discovery of photosynthesis as a significant contributor to surface storm potential and overall tornadic regulation can help define patterns that not only help predict, but also may help future researchers in climatology and engineering to investigate ways to nullify conditions leading to such destructive forces approaching population centers. More important, these new research methods may help overall understanding of surface air motion in a way that is enhanced by emerging GIS and remote sensing technologies

The Effect of Isomorphic Pitch Layouts on the Transfer of Musical Learning ^†

The physical arrangement of pitches in most traditional musical instruments&#8212;including the piano and guitar&#8212;is non-isomorphic, which means that a given spatial relationship between two keys, buttons, or fretted strings can produce differing musical pitch intervals. Recently, a number of new musical interfaces have been developed with isomorphic pitch layouts where these relationships are consistent. Since the nineteenth century, it has been widely considered that isomorphic pitch layouts facilitate the learnability and playability of instruments, particularly when a piece is transposed into a different key; however, prior to this paper, this has not been experimentally tested. To address this, we investigated four different pitch layouts to examine whether isomorphism facilitates retention and transfer of musical learning within and across keys. Both non-musicians and musicians were tested on two training tasks: two immediate retention tasks and a transfer task. Each participant played every task on two distinct layouts&#8212;one being an isomorphic layout (Wicki or Bosanquet), the other being a minimally adjusted non-isomorphic version. For musicians, isomorphism was found to facilitate transfer of learning to a novel task; for non-musicians, the results were mixed. This study provides insight into features that are important to music instrument design

The Role of Platelets in Venous Thromboembolism

Multiple factors contribute to the risk of venous thromboembolism (VTE). Platelets have attracted much interest in arterial cardiovascular disease, whereas their role in VTE has received much less attention. Recent evidence suggests that platelets may play a more important role in VTE than previously anticipated. This review discusses the mechanisms that link platelets with venous thrombotic disease and their potential applications as novel risk factors for VTE. In addition, animal studies and randomized clinical trials that highlight the potential effect of antiplatelet therapy in venous thrombosis are evaluated to assess the role of platelets in VTE. The clinical significance of platelets for VTE risk assessment in specific patient cohorts and their role as a suitable therapeutic target for VTE prevention is acknowledged. The role of platelets in VTE is a promising field for future research

Differences in coagulation-relevant parameters: Comparing cryoprecipitate and a human fibrinogen concentrate

Background Variable fibrinogen content within cryoprecipitate makes accurate dosing challenging in patients with coagulopathic bleeding, in addition to pathogen transmission risks associated with its administration. Purified and standardized human fibrinogen concentrates (HFCs) represent reliable alternatives. Full cryoprecipitate characterization is required to inform selection of an appropriate fibrinogen source for supplementation therapy. Methods Extended biochemical comparison of pooled cryoprecipitate and HFC (Fibryga, Octapharma) was performed using commercially available assays to determine levels of variability in cryoprecipitate and HFC. In addition to standard procoagulant factors, measurements included activities of platelet-derived microparticles (PMPs) and plasminogen, and levels of fibrin degradation products. Results Cryoprecipitate contains lower fibrinogen levels than HFC (4.83 vs.19.73 g/L; pConclusion The tested HFC is a more reliable fibrinogen and FXIII source for accurate dosing compared with cryoprecipitate. Cryoprecipitate appears considerably less predictable for bleeding management due to wide variation in pro- and anticoagulation factors, the presence of PMPs, and the potential to elevate VWF and FVIII to prothrombotic levels