UNASSIGNED: The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal @entity432 is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In @entity64 , an anoxic tissue compartment (the " @entity1188 core") is surrounded by a @entity519 compartment (the "ischaemic penumbra"). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6  h  unless salvaged by arterial recanalisation. Establishment of an equivalent @entity519 compartment within the inner @entity2788 following @entity732 ( @entity732 ) isn't widely acknowledged. During experimental @entity732 , electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, @entity519 and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the @entity519 survival time (   2  h) expires, the contribution from the @entity1188 is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Inbetween these compartments, an annular @entity519 zone (the "penumbra obscura") endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of "partial" @entity732 . Persistent retinal @entity1211 signifies maximal extraction of @entity26 by an enduring "polar penumbra" that permeates or largely replaces the @entity1188 core. On retinal reperfusion some days later, the retinal venous @entity26 saturation reverts to normal and vision improves. Thus, penumbral inner @entity2788 , marginally oxygenated by the choroid or by residual circulation, isn't at risk of delayed apoptotic @entity1188 (unlike @entity519 cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of @entity732 exceeds 2  h.

Evidence for an enduring ischaemic penumbra following XXXX , with implications for fibrinolytic therapy.

@entity64 :: ('MESH:D020521', 'Disease') :: ['cerebral stroke'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity2788 :: ('MESH:D015785', 'Disease') :: ['retina'] @entity519 :: ('MESH:D000860', 'Disease') :: ['anoxia', 'hypoxic'] @entity1188 :: ('MESH:D007238', 'Disease') :: ['infarcted posterior retina', 'infarct', 'infarction'] @entity432 :: ('MESH:D001157', 'Disease') :: ['arterial occlusion'] @entity732 :: ('MESH:D015356', 'Disease') :: ['central retinal artery occlusion', 'CRAO'] @entity1211 :: ('MESH:D054556', 'Disease') :: ['venous hypoxaemia']
@entity732 :: (MESH:D015356,Disease) :: ['central retinal artery occlusion']
