In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

Endovascularly retrieved clots may be a potential resource for diagnosing stroke etiology. This method may influence secondary prevention treatment. We measure thrombin activity eluted by serially washing clots. We concluded that an assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.

Benthic fauna in the south-eastern part of the Pechora-sea: Current state and analysis of ecological quality.

In recent decades, economic activity has sharply increased in the Pechora Sea, one of the most hydrologically unique areas of the Barents Sea. Hence, the information about the current state of its ecosystems is quite important for assessing their possible changes in the future. The aim of the present study was to analyze the distribution of macrobenthos and assess its ecological quality in the southeastern part of the Pechora Sea at the beginning of the 21st century (based on data collected in 2012-2013). The results showed that since 1920s there have been no serious changes in the macrobenthos in the studied area. The weak shifts detected in the benthic fauna were either within the natural range of fluctuations in population of common species, or may be associated with differences in the methodological approaches of different researches. Heterogeneity in the macrobenthos distribution, the most significant abiotic factors identified in relation to it, quantitative indicators of biota, and species dominating in communities were similar to those revealed in previous studies. As of 2013, the characteristics of benthic communities in the southeastern part of the Pechora Sea, including their ecological quality, allow us to refer them as undisturbed biosystems.

In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

BACKGROUND: Endovascularly retrieved clots are a potential resource for diagnosing stroke etiology, which may influence secondary prevention treatment. In this study we measured thrombin activity eluted by serially washing clots. METHODS: Clots were retrieved from 68 patients with acute ischemic stroke, freshly frozen and classified by standard criteria into proven atrial fibrillation (AF, 18 patients), atherosclerotic origin (AS, 15 patients), cryptogenic stroke (Cr, 17 patients) and other known causes (18 patients). Thawed clot samples were washed by transferring them into 1 mL buffer in seven hourly cycles and a fluorescent substrate assay was used to measure secreted thrombin activity. The clots were also examined histologically. Artificial fibrin and red blood cell-rich clots were similarly assayed for wash-eluted thrombin activity as an external control. RESULTS: Thrombin activity eluted from clots of AF origin decreased significantly with time in contrast to steady levels eluted from AS origin thrombi (P<0.0001 by repeated measures ANOVA). The Cr stroke group was indistinguishable from the AF group and differed statistically from the AS group (P=0.017 by repeated measures ANOVA). In artificial clots we found a biphasic activity pattern, with initially decreasing levels of eluted thrombin (AF pattern) and then, with continuing washes, steady eluted thrombin levels (AS pattern). CONCLUSIONS: An assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.