Hyperphosphatemia,Phosphoprotein Phosphatases,and Microparticle Release in Vascular Endothelial Cells

Hyperphosphatemia in patients with advanced CKD is thought to be an important contributor to cardiovascular risk, in part because of endothelial cell (EC) dysfunction induced by inorganic phosphate (Pi). Such patients also have an elevated circulating concentration of procoagulant endothelial microparticles (MPs), leading to a prothrombotic state, which may contribute to acute occlusive events. We hypothesized that hyperphosphatemia leads to MP formation from ECs through an elevation of intracellular Pi concentration, which directly inhibits phosphoprotein phosphatases, triggering a global increase in phosphorylation and cytoskeletal changes. In cultured human ECs (EAhy926), incubation with elevated extracellular Pi (2.5 mM) led to a rise in intracellular Pi concentration within 90 minutes. This was mediated by PiT1/slc20a1 Pi transporters and led to global accumulation of tyrosine- and serine/threonine-phosphorylated proteins, a marked increase in cellular Tropomyosin-3, plasma membrane blebbing, and release of 0.1- to 1-μm-diameter MPs. The effect of Pi was independent of oxidative stress or apoptosis. Similarly, global inhibition of phosphoprotein phosphatases with orthovanadate or fluoride yielded a global protein phosphorylation response and rapid release of MPs. The Pi-induced MPs expressed VE-cadherin and superficial phosphatidylserine, and in a thrombin generation assay, they displayed significantly more procoagulant activity than particles derived from cells incubated in medium with a physiologic level of Pi (1 mM). These data show a mechanism of Pi-induced cellular stress and signaling, which may be widely applicable in mammalian cells, and in ECs, it provides a novel pathologic link between hyperphosphatemia, generation of MPs, and thrombotic risk.     

Serious gaming technology in major incident triage training: A pragmatic controlled trial

Objective

By exploiting video games technology, serious games strive to deliver affordable, accessible and usable interactive virtual worlds, supporting applications in training, education, marketing and design. The aim of the present study was to evaluate the effectiveness of such a serious game in the teaching of major incident triage by comparing it with traditional training methods.

Design

Pragmatic controlled trial.

Method

During Major Incident Medical Management and Support Courses, 91 learners were randomly distributed into one of two training groups: 44 participants practiced triage sieve protocol using a card-sort exercise, whilst the remaining 47 participants used a serious game. Following the training sessions, each participant undertook an evaluation exercise, whereby they were required to triage eight casualties in a simulated live exercise. Performance was assessed in terms of tagging accuracy (assigning the correct triage tag to the casualty), step accuracy (following correct procedure) and time taken to triage all casualties. Additionally, the usability of both the card-sort exercise and video game were measured using a questionnaire.

Results

Tagging accuracy by participants who underwent the serious game training was significantly higher than those who undertook the card-sort exercise [Chi2 = 13.126, p = 0.02]. Step accuracy was also higher in the serious game group but only for the numbers of participants that followed correct procedure when triaging all eight casualties [Chi2 = 5.45, p = 0.0196]. There was no significant difference in time to triage all casualties (card-sort = 435 ± 74 s vs video game = 456 ± 62 s, p = 0.155).

Conclusion

Serious game technologies offer the potential to enhance learning and improve subsequent performance when compared to traditional educational methods.     

CO2 effects on local-lesion production by tobacco mosaic virus and turnip mosaic virus

Nicotiana tabacum var. Havana 425 and N. glutinosa plants were inoculated with tobacco mosaic virus (TMV) and those of N. tabacum var. Haranova with turnip mosaic virus (TuMV). After inoculation, plants were kept in normal air or in 1% CO₂, either continuously, only during the light period, or only during the dark period. When plants were exposed to 1% CO₂ during the light period, lesion production in all three hosts was greatly inhibited. In other CO₂ treatments the number of lesions produced was similar to the control (normal air). However, in plants of N. tabacum var. Havana 425 exposed to 1% CO₂, either during the dark period or continuously, lesions were yellow instead of the usual brown. In addition, lesions developed on leaves exposed to 1% CO₂ during dark or light periods were smaller than in the other two treatments. In the yellow lesions there was frequently a new type of particle aggregation, called zipper aggregates, indicating that variation in the environment can cause changes in the structure of the TMV aggregates.