Embolic strokes of undetermined source in young adults: baseline characteristics and long-term outcome.

BACKGROUND AND PURPOSE: Embolic strokes of undetermined source (ESUS) are a recent entity, not yet thoroughly investigated in young stroke patients. The clinical characteristics and long-term risks of vascular events and all-cause mortality between young-onset ESUS and other aetiological subgroups were compared. METHODS: Patients with ESUS were identified amongst the 1008 patients aged 15-49 years with first-ever ischaemic stroke in Helsinki Young Stroke Registry, and primary end-points were defined as recurrent stroke, composite vascular events and all-cause mortality. Cumulative 15-year risks for each end-point were analysed with life tables and adjusted risks were based on Cox proportional hazard analyses. RESULTS: Of the 971 eligible patients, 203 (20.9%) were classified as ESUS. They were younger (median age 40 years, interquartile range 32-46 vs. 45 years, 39-47), more often female (43.3% vs. 35.7%) and had fewer cardiovascular risk factors than other modified TOAST groups. With a median follow-up time of 10.1 years, ESUS patients had the second lowest cumulative risk of recurrent stroke and composite vascular events and lowest mortality compared to other TOAST groups. Large-artery atherosclerosis and small vessel disease carried significantly higher risk for recurrent stroke than did ESUS, whilst no difference appeared between cardioembolism from high-risk sources and ESUS. CONCLUSIONS: In our cohort, ESUS patients were younger and had milder cardiovascular risk factor burden and generally better long-term outcome compared to other causes of young-onset stroke. The comparable risk of recurrent stroke between ESUS and high-risk sources of cardioembolism might suggest similarities in their pathophysiology.

Experimental evidence of predation by juvenile flounder, Platichthys flesus, on a shallow water meiobenthic community.

In the northern Baltic Sea juvenile flounder, Platichthys flesus, occur in high abundances on shallow sandy bottoms in late summer and autumn. They feed mainly on meiofauna and the ontogenetic switch to macrofaunal sized food occurs at a larger size here than in other areas, exemplifying the high relative importance of meiofauna. Consequently, juvenile P. flesus in the Baltic feed for a longer period on meiofauna, and could thus be expected to have a stronger predation effect on the meiofaunal assemblages. In this study the predation effects of juvenile P. flesus on meiofaunal abundances and community structure were studied using microcosms that were sampled repeatedly over a 3-week period. Significant differences between treatment and control were found for the total number of taxa, for abundances of harpacticoids, copepod nauplii and ostracods. The nematode community was not affected, but one genus, Axonolaimus, was negatively affected by predation. The predation affected meiofaunal community structure as the major taxon diversity was significantly reduced. The results suggest that the meiofauna on shallow sandy bottoms may be structured by juvenile P. flesus, and the combined predation pressure of juvenile flounder and other epibenthic predators in the area might be considerable. Microcosms are effective in testing natural predation, especially on meiofaunal communities, but field experiments should be conducted to account for the physical characteristics of the area studied.