An innovative cold storage system for donor heart transportation-lessons learned from the first experience in Switzerland.

BACKGROUND: The current standard for donor heart preservation consists of cold organ storage in three sequential plastic bags. This technique can cause freezing injuries of the donor heart as the temperature inside the transport box is not monitored routinely. The SherpaPak™ Cardiac Transport System (CTS) (Paragonix Technologies, Cambridge, MA, USA) aims to resolve this problem by maintaining a controlled preservation temperature between 4 and 8 °C. This study reports the first single-centre experience in Switzerland with this innovative single-use disposable device. METHODS: Between May and December 2020, four heart procurements using SherpaPak™ CTS were performed at our heart centre. Donor heart preservation fluid and ambient temperature were monitored using the InTempConnect® application (Onset Computer Corporation, Bourne, MA, USA). All patient data were collected retrospectively from the local hospital patient data capture system. RESULTS: Four recipients of a donor heart preserved with SherpaPak™ CTS were included in this study (3 male, 1 female). Mean transport distance was 86 km (range, 45-276 km). Mean storage time in the cooler was 73.5±19.33 minutes. Mean cold ischemic time was 199.25±11.67 minutes. The device kept the average organ temperature between 5.2 and 8.8 °C and hereby reached the recommended temperature range of 5-10 °C. Modifications of the procurement and storage process provided an optimization of the temperature course in the transportation box. There were no incidents during the transport. Organs transported with this novel storage system showed normal function after transplantation. CONCLUSIONS: The SherpaPak™ CTS provides constant organ temperatures during transportation, prevents freezing injury and ensures mechanical protection of the graft. KEYWORDS: Heart transplantation; organ procurement; cold storage; hypothermic injury; graft transport.

Using task effort and pupil size to track covert shifts of visual attention independently of a pupillary light reflex.

We tested the link between pupil size and the task effort involved in covert shifts of visual attention. The goal of this study was to establish pupil size as a marker of attentional shifting in the absence of luminance manipulations. In three experiments, participants evaluated two stimuli that were presented peripherally, appearing equidistant from and on opposite sides of eye fixation. The angle between eye fixation and the peripherally presented target stimuli varied from 12.5° to 42.5°. The evaluation of more distant stimuli led to poorer performance than did the evaluation of more proximal stimuli throughout our study, confirming that the former required more effort than the latter. In addition, in Experiment 1 we found that pupil size increased with increasing angle and that this effect could not be reduced to the operation of low-level visual processes in the task. In Experiment 2 the pupil dilated more strongly overall when participants evaluated the target stimuli, which required shifts of attention, than when they merely reported on the target's presence versus absence. Both conditions yielded larger pupils for more distant than for more proximal stimuli, however. In Experiment 3, we manipulated task difficulty more directly, by changing the contrast at which the target stimuli were presented. We replicated the results from Experiment 1 only with the high-contrast stimuli. With stimuli of low contrast, ceiling effects in pupil size were observed. Our data show that the link between task effort and pupil size can be used to track the degree to which an observer covertly shifts attention to or detects stimuli in peripheral vision.

Beyond Verb Meaning: Experimental Evidence for Incremental Processing of Semantic Roles and Event Structure.

We present an event-related potentials (ERP) study that addresses the question of how pieces of information pertaining to semantic roles and event structure interact with each other and with the verb's meaning. Specifically, our study investigates German verb-final clauses with verbs of motion such as fliegen 'fly' and schweben 'float, hover,' which are indeterminate with respect to agentivity and event structure. Agentivity was tested by manipulating the animacy of the subject noun phrase and event structure by selecting a goal adverbial, which makes the event telic, or a locative adverbial, which leads to an atelic reading. On the clause-initial subject, inanimates evoked an N400 effect vis-à-vis animates. On the adverbial phrase in the atelic (locative) condition, inanimates showed an N400 in comparison to animates. The telic (goal) condition exhibited a similar amplitude like the inanimate-atelic condition. Finally, at the verbal lexeme, the inanimate condition elicited an N400 effect against the animate condition in the telic (goal) contexts. In the atelic (locative) condition, items with animates evoked an N400 effect compared to inanimates. The combined set of findings suggest that clause-initial animacy is not sufficient for agent identification in German, which seems to be completed only at the verbal lexeme in our experiment. Here non-agents (inanimates) changing their location in a goal-directed way and agents (animates) lacking this property are dispreferred and this challenges the assumption that change of (locational) state is generally a defining characteristic of the patient role. Besides this main finding that sheds new light on role prototypicality, our data seem to indicate effects that, in our view, are related to complexity, i.e., minimality. Inanimate subjects or goal arguments increase processing costs since they have role or event structure restrictions that animate subjects or locative modifiers lack.

Decision-related factors in pupil old/new effects: Attention, response execution, and false memory.

In this study, we investigate the effects of decision-related factors on recognition memory in pupil old/new paradigms. In Experiment 1, we used an old/new paradigm with words and pseudowords and participants made lexical decisions during recognition rather than old/new decisions. Importantly, participants were instructed to focus on the nonword-likeness of presented items, not their word-likeness. We obtained no old/new effects. In Experiment 2, participants discriminated old from new words and old from new pseudowords during recognition, and they did so as quickly as possible. We found old/new effects for both words and pseudowords. In Experiment 3, we used materials and an old/new design known to elicit a large number of incorrect responses. For false alarms ("old" response for new word), we found larger pupils than for correctly classified new items, starting at the point at which response execution was allowed (2750ms post stimulus onset). In contrast, pupil size for misses ("new" response for old word) was statistically indistinguishable from pupil size in correct rejections. Taken together, our data suggest that pupil old/new effects result more from the intentional use of memory than from its automatic use.

Pupil old/new effects reflect stimulus encoding and decoding in short-term memory.

We conducted five pupil old/new experiments to examine whether pupil old/new effects can be linked to familiarity and/or recollection processes of recognition memory. In Experiments 1-3, we elicited robust pupil old/new effects for legal words and pseudowords (Experiment 1), positive and negative words (Experiment 2), and low-frequency and high-frequency words (Experiment 3). Importantly, unlike for old/new effects in ERPs, we failed to find any effects of long-term memory representations on pupil old/new effects. In Experiment 4, using the words and pseudowords from Experiment 1, participants made lexical decisions instead of old/new decisions. Pupil old/new effects were restricted to legal words. Additionally requiring participants to make speeded responses (Experiment 5) led to a complete absence of old/new effects. Taken together, these data suggest that pupil old/new effects do not map onto familiarity and recollection processes of recognition memory. They rather seem to reflect strength of memory traces in short-term memory, with little influence of long-term memory representations. Crucially, weakening the memory trace through manipulations in the experimental task significantly reduces pupil/old new effects.