Ecological and evolutionary consequences of selective interspecific information use.

Recent work has shown that animals frequently use social information from individuals of their own species as well as from other species; however, the ecological and evolutionary consequences of this social information use remain poorly understood. Additionally, information users may be selective in their social information use, deciding from whom and how to use information, but this has been overlooked in an interspecific context. In particular, the intentional decision to reject a behaviour observed via social information has received less attention, although recent work has indicated its presence in various taxa. Based on existing literature, we explore in which circumstances selective interspecific information use may lead to different ecological and coevolutionary outcomes between two species, such as explaining observed co-occurrences of putative competitors. The initial ecological differences and the balance between the costs of competition and the benefits of social information use potentially determine whether selection may lead to trait divergence, convergence or coevolutionary arms race between two species. We propose that selective social information use, including adoption and rejection of behaviours, may have far-reaching fitness consequences, potentially leading to community-level eco-evolutionary outcomes. We argue that these consequences of selective interspecific information use may be much more widespread than has thus far been considered.

Finnish flow diverter study: 8 years of experience in the treatment of acutely ruptured intracranial aneurysms.

BACKGROUND: Flow diversion of acutely ruptured intracranial aneurysms (IAs) is controversial due to high treatment-related complication rates and a lack of supporting evidence. We present clinical and radiological results of the largest series to date. METHODS: This is a nationwide retrospective study of acutely ruptured IAs treated with flow diverters (FDs). The primary outcome was the modified Rankin Scale (mRS) score at the last available follow-up time. Secondary outcomes were treatment-related complications and the aneurysm occlusion rate. RESULTS: 110 patients (64 females; mean age 55.7 years; range 12-82 years) with acutely ruptured IAs were treated with FDs between 2012 and 2020 in five centers. 70 acutely ruptured IAs (64%) were located in anterior circulation, and 47 acutely ruptured IAs (43%) were blister-like. A favorable functional outcome (mRS 0-2) was seen in 73% of patients (74/102). Treatment-related complications were seen in 45% of patients (n=49). Rebleeding was observed in 3 patients (3%). The data from radiological follow-ups were available for 80% of patients (n=88), and complete occlusion was seen in 90% of aneurysms (79/88). The data from clinical follow-ups were available for 93% of patients (n=102). The overall mortality rate was 18% (18/102). CONCLUSIONS: FD treatment yields high occlusion for acutely ruptured IAs but is associated with a high risk of complications. Considering the high mortality rate of aneurysmal subarachnoid hemorrhage, the prevention of rebleeding is crucial. Thus, FD treatment may be justified as a last resort option.

Foraging Bumblebees Selectively Attend to Other Types of Bees Based on Their Reward-Predictive Value.

Using social information can be an efficient strategy for learning in a new environment while reducing the risks associated with trial-and-error learning. Whereas social information from conspecifics has long been assumed to be preferentially attended by animals, heterospecifics can also provide relevant information. Because different species may vary in their informative value, using heterospecific social information indiscriminately can be ineffective and even detrimental. Here, we evaluated how selective use of social information might arise at a proximate level in bumblebees (Bombus terrestris) as a result of experience with demonstrators differing in their visual appearance and in their informative value as reward predictors. Bumblebees were first trained to discriminate rewarding from unrewarding flowers based on which type of "heterospecific" (one of two differently painted model bees) was next to each flower. Subsequently, these bumblebees were exposed to a novel foraging context with two live painted bees. In this novel context, observer bumblebees showed significantly more social information-seeking behavior towards the type of bees that had predicted reward during training. Bumblebees were not attracted by paint-marked small wooden balls (moved via magnets) or paint-marked non-pollinating heterospecifics (woodlice; Porcellio laevis) in the novel context, indicating that bees did not simply respond to conditioned color cues nor to irrelevant social cues, but rather had a "search image" of what previously constituted a valuable, versus invaluable, information provider. The behavior of our bumblebees suggests that their use of social information is governed by learning, is selective, and extends beyond conspecifics.

Functional imaging with 11C-metomidate PET for subtype diagnosis in primary aldosteronism.

OBJECTIVE: Endocrine Society guidelines recommend adrenal venous sampling (AVS) in primary aldosteronism (PA) if adrenalectomy is considered. We tested whether functional imaging of adrenal cortex with 11C-metomidate (11C-MTO) could offer a noninvasive alternative to AVS in the subtype classification of PA. DESIGN: We prospectively recruited 58 patients with confirmed PA who were eligible for adrenal surgery. METHODS: Subjects underwent AVS and 11C-MTO-PET without dexamethasone pretreatment in random order. The lateralization of 11C-MTO-PET and adrenal CT were compared with AVS in all subjects and in a prespecified adrenalectomy subgroup in which the diagnosis was confirmed with immunohistochemical staining for CYP11B2. RESULTS: In the whole study population, the concordance of AVS and 11C-MTO-PET was 51% and did not differ from that of AVS and adrenal CT (53%). The concordance of AVS and 11C-MTO-PET was 55% in unilateral and 44% in bilateral PA. In receiver operating characteristics analysis, the maximum standardized uptake value ratio of 1.16 in 11C-MTO-PET had an AUC of 0.507 (P = n.s.) to predict allocation to adrenalectomy or medical therapy with sensitivity of 55% and specificity of 44%. In the prespecified adrenalectomy subgroup, AVS and 11C-MTO-PET were concordant in 10 of 19 subjects with CYP11B2-positive adenoma and in 6 of 10 with CYP11B2-positivity without an adenoma. CONCLUSIONS: The concordance of 11C-MTO-PET with AVS was clinically suboptimal, and did not outperform adrenal CT. In a subgroup with CYP11B2-positive adenoma, 11C-MTO-PET identified 53% of cases. 11C-MTO-PET appeared to be inferior to AVS for subtype classification of PA.

Interspecific information on predation risk affects nest site choice in a passerine bird.

BACKGROUND: Breeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice. RESULTS: Our results demonstrate that flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk. CONCLUSIONS: Copying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions.

Chronic Infarcts Predict Poor Clinical Outcome in Mechanical Thrombectomy of Sexagenarian and Older Patients.

BACKGROUND: The impact of lacunar and cortical chronic ischemic lesions (CILs) on the clinical outcome of mechanical thrombectomy (MT) has been little studied. Clinical trials suggest that older patients benefit from MT. We investigated the effect of CILs on the clinical outcome of sexagenarian and older patients with acute middle cerebral artery (MCA) or distal internal carotid artery (ICA) stroke who received MT to treat large-vessel occlusion (LVO). METHODS: We prospectively collected the clinical and imaging data of 130 consecutive MT patients of which 68 met the inclusion criteria. We limited the analysis to sexagenarian and older subjects and occlusions no distal than the M2 segment. Baseline clinical, procedural and imaging variables, technical outcome, 24-hour imaging outcome, and the clinical outcome were recorded. Differences between patients with and without CILs were studied with appropriate statistical tests and binary logistic regression analysis. RESULTS: Twenty-one patients (31%) had at least 1 CIL. Thirty-eight percent of patients with CIL(s) compared with 62% without (P = .06) experienced good clinical outcome (3-month modified Rankin Scale ≤ 2). A similar nonsignificant trend was seen when lacunar lesions, lesion multiplicity, and chronic white matter lesions were examined separately. Absence of CIL increased the odds of good clinical outcome 3.7-fold (95% confidence interval 1.0-10.7, P = .05) in logistic regression modeling. CONCLUSIONS: Chronic cortical and lacunar infarcts in admission imaging are associated with poor clinical outcome in sexagenarian and older patients treated with MT for LVO of the MCA or distal ICA.

Internal Carotid Artery and the Proximal M1 Segment Are Optimal Targets for Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: Mechanical thrombectomy (MT) is an established treatment of acute anterior circulation stroke caused by large vessel occlusion (LVO). We compared the clinical outcome (3-month modified Rankin Scale, mRS) in hyperacute (<3h from the onset of symptoms) ischemic stroke between an MT and an intravenous thrombolysis (IVT) cohort in proximal (ICA and the proximal M1 segment of the middle cerebral artery) and distal (the distal M1 and the M2 segment) LVOs. METHODS: We prospectively reviewed 67 patients who underwent MT with newer-generation stent retrievers. The IVT cohort consisted of 98 patients who received IVT without MT. We recorded baseline clinical, procedural and imaging variables, technical outcome, 24-h imaging outcome, and the clinical outcome. Differences between the groups were studied with theoretically appropriate statistical tests and binary logistic regression analysis. RESULTS: The proportion of patients who had a proximal LVO and experienced good (mRS ≤2) or excellent (mRS ≤1) clinical outcome was significantly larger in the MT group (62 vs. 7%, p < 0.001; 47 vs. 3%, p < 0.001, respectively). In a regression model including relevant confounding variables, good clinical outcome was seen significantly more often among patients with proximal occlusions (OR = 6.0, CI 95% 1.9-18.3, p = 0.002). In a similar model, no statistically significant differences were observed in patients with more distal occlusions. CONCLUSIONS: MT is superior to IVT in achieving good clinical outcome in hyperacute anterior circulation stroke in the most proximal occlusions (ICA and proximal M1 segment). In the distal M1 and M2 segments neither of these therapies clearly outperforms the other.

TREVO and Capture LP have equal technical success rates in mechanical thrombectomy of proximal and distal anterior circulation occlusions.

PURPOSE: Mechanical thrombectomy (MT) is a proven method to treat large vessel occlusions in acute anterior circulation stroke. We compared the technical, imaging, and clinical outcomes of MT performed with either TREVO or Capture LP devices. METHODS: There were 42 and 43 patients in the TREVO and Capture LP groups, respectively. Baseline variables, technical outcome (Thrombolysis In Cerebral Infarction, TICI), 24 hours imaging outcome, and 3-month clinical outcome (modified Rankin Scale, mRS) were prospectively recorded. The patients were stratified according to clot location, groups compared, and logistic regression models devised to study the effect of device selection on the clinical outcome. RESULTS: The technical success rates were equal in both proximal (internal carotid artery and proximal M1 segment) and distal occlusions (distal M1 and M2 segments). The proportion of TICI 2b or 3 was 96% and 87% with TREVO and 87% and 89% with Capture LP (p=0.25 and p=0.80, respectively). Device selection did not significantly predict good clinical outcome (mRS ≤2) in either proximal or distal occlusions. In multivariate analysis, selecting Capture LP borderline significantly increased the odds of an excellent outcome close to sixfold both in proximal and distal occlusions (OR 6.7, 95% CI 0.82 to 53.7, p=0.08 and OR 5.7, 95% CI 0.88 to 37.8, p=0.07, respectively). CONCLUSIONS: TREVO and Capture LP perform equally well in proximal and distal occlusions in the anterior circulation when technical and good clinical outcome are considered. Capture LP may have a small advantage in reaching mRS ≤1 at 3 months. However, this needs to be confirmed in a randomized study.

Low Cerebral Blood Volume Identifies Poor Outcome in Stent Retriever Thrombectomy.

BACKGROUND: Mechanical thrombectomy (MT) is an efficient treatment of acute stroke caused by large-vessel occlusion. We evaluated the factors predicting poor clinical outcome (3-month modified Rankin Scale, mRS >2) although MT performed with modern stent retrievers. METHODS: We prospectively collected the clinical and imaging data of 105 consecutive anterior circulation stroke patients who underwent MT after multimodal CT imaging. Patients with occlusion of the internal carotid artery and/or middle cerebral artery up to the M2 segment were included. We recorded baseline clinical, procedural and imaging variables, technical outcome, 24-h imaging outcome and the clinical outcome. Differences between the groups were studied with appropriate statistical tests and binary logistic regression analysis. RESULTS: Low cerebral blood volume Alberta stroke program early CT score (CBV-ASPECTS) was associated with poor clinical outcome (median 7 vs. 9, p = 0.01). Lower collateral score (CS) significantly predicted poor outcome in regression modelling with CS = 0 increasing the odds of poor outcome 4.4-fold compared to CS = 3 (95% CI 1.27-15.5, p = 0.02). Lower CBV-ASPECTS significantly predicted poor clinical outcome among those with moderate or severe stroke (OR 0.82, 95% CI 0.68-1, p = 0.05) or poor collateral circulation (CS 0-1, OR 0.66, 95% CI 0.48-0.90, p = 0.009) but not among those with mild strokes or good collaterals. CONCLUSIONS: CBV-ASPECTS estimating infarct core is a significant predictor of poor clinical outcome among anterior circulation stroke patients treated with MT, especially in the setting of poor collateral circulation and/or moderate or severe stroke.

Stent Retriever Thrombectomy in Different Thrombus Locations of Anterior Cerebral Circulation.

BACKGROUND: Mechanical thrombectomy (MT) is a safe and efficient treatment for acute ischemic stroke in patients with proximal anterior occlusion and large penumbra. We evaluated the technical and clinical success of MT in relation to the location of the occlusion (internal carotid artery, M1 and M2 segments of the middle cerebral artery). METHODS: We prospectively reviewed 130 patients of whom 105 met the inclusion criteria. Baseline clinical, procedural and imaging variables, technical outcome (TICI, thrombolysis in cerebral infarction), 24 h imaging outcome and three-month clinical outcome (mRS, modified Rankin Scale) were recorded. Differences between the groups were studied with statistical tests according to the type of the variable. RESULTS: There were 37, 46 and 22 patients in the internal carotid artery (ICA), M1 and M2 groups, respectively. TICI 2b or 3 was achieved in 92 cases (88 %) with a non-significant trend towards a better recanalization outcome in the ICA and M1 groups. Overall, 57 of the 105 patients (55 %) experienced favorable clinical outcome (mRS ≤ 2) with no significant differences between the groups. Excellent outcome (mRS ≤ 1) was seen in 40 patients (39 %) and there proportionally more patients with excellent outcome in the ICA and M1 groups (ICA: 44 %, M1: 41 %, M2: 23 % of patients, p = 0.22). CONCLUSIONS: There were no statistically significant differences in the technical or clinical outcomes between the different sites of occlusion (ICA, M1 or M2). There was a non-significant trend towards achieving excellent clinical outcome (3-month mRS ≤ 1) more often and better recanalization results in the two more proximal locations.

Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community.

BACKGROUND: Social information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds. RESULTS: Of the examined species, resident great tits (Parus major) preferred the symbol that had been associated with unoccupied nest boxes in the previous year, i.e., their preference shifted towards niche space previously unused by putative competitors and conspecifics. CONCLUSIONS: Our results show that animals can remember the earlier resource use of conspecifics and other guild members and adjust own decisions accordingly one year after. Our experiment cannot reveal the ultimate mechanism(s) behind the observed behaviour but avoiding costs of intra- or interspecific competition or ectoparasite load in old nests are plausible reasons. Our findings imply that interspecific social information use can affect resource sharing and realized niches in ecological time-scale through active avoidance of observed decisions and behavior of potentially competing species.

Active hiding of social information from information-parasites.

BACKGROUND: Coevolution between pairs of different kind of entities, such as providers and users of information, involves reciprocal selection pressures between them as a consequence of their ecological interaction. Pied flycatchers (Ficedula hypoleuca) have been shown to derive fitness benefits (larger clutches) when nesting in proximity to great tits (Parus major), presumably because they this way discover and obtain information about nesting sites. Tits suffer from the resulting association (smaller clutches). An arms race between the tits (information host) and the flycatchers (information parasite) could thus result. Great tits often cover eggs with nesting material before, but not during incubation. We hypothesized that one function of egg-covering could be a counter-adaptation to reduce information parasitism by pied flycatchers. We predicted that tits should bring more new hair to cover their exposed eggs when a pied flycatcher is present near to tit nest than when a neutral (non-competing) species is present. We conducted decoy and playback experiment in Oulu and Turku, Finland. First, we removed and collected all the hair covering the tit eggs. Then, we measured how the perceived presence of flycatcher or waxwing (Bombycilla garrulus) affects tits' egg-covering by collecting and weighing the hair brought on the eggs and photographing the nest 24 h after the playback. RESULTS: Tits brought more hair into the nest and covered the eggs more carefully after flycatcher treatment, compared to waxwing treatment. We also found that the tits in Oulu (over 600 km to north from Turku) had more hair on the top of their eggs in general. CONCLUSIONS: Together, these results suggest that the counter-adaptation function of egg-covering against information parasites may be an extension of original function to protect eggs from low temperatures.

Observed fitness may affect niche overlap in competing species via selective social information use.

Social information transmission is important because it enables horizontal spread of behaviors, not only between conspecifics but also between individuals of different species. Because interspecific social information use is expected to take place among species with similar resource needs, it may have major consequences for the emergence of local adaptations, resource sharing, and community organization. Social information use is expected to be selective, but the conditions promoting it in an interspecific context are not well known. Here, we experimentally test whether pied flycatchers (Ficedula hypoleuca) use the clutch size of great tits (Parus major) in determining the quality of the observed individual and use it as a basis of decision making. We show that pied flycatchers copied or rejected a novel nest site feature preference of great tits experimentally manipulated to exhibit high or low fitness (clutch size), respectively. Our results demonstrate that the social transmission of behaviors across species can be highly selective in response to observed fitness, plausibly making the phenomenon adaptive. In contrast with the current theory of species coexistence, overlap between realized niches of species could dynamically increase or decrease depending on the observed success of surrounding individuals.

[Mechanical thrombectomy in the treatment of acute disturbance of cerebral circulation]. / Mekaaninen trombektomia akuutin aivoverenkierron häiriön hoidossa.

An essential aim of acute treatment of brain infarction is to restrict the size of the infarct by rapid and permanent recanalization of the obstructed artery. Thrombolytic therapy based on intravenous administration of alteplas (IV-tPA) exhibits the highest efficacy in the treatment of cerebral artery thrombi that are fairly small or intermediate in size. Intra-arterial thrombolysis (IA-tPA) and mechanical thrombectomy can be considered, if IV-tPA turns out to be ineffective or is contraindicated. In situations where the expected effect of IV-tPA:n is modest per se, mechanical thrombectomy should be taken into account as part of the therapeutic strategy.

Stent-assisted embolization of recurrent or residual intracranial aneurysms.

INTRODUCTION: Intracranial stents have theoretical advantages in the treatment of wide-necked intracranial aneurysms, but the usability of intracranial stents in the retreatment of recurrent intracranial aneurysms is relatively unknown. In this study, we aim to evaluate the safety and efficacy of stent-assisted embolization in the retreatment of recurrent or residual intracranial aneurysms. METHODS: Retrospective evaluation was carried out for 55 consecutive patients (17 men and 38 women; mean age 51.5 years), with 56 recurrent or residual intracranial aneurysms electively retreated with stent-assisted embolization. RESULTS: The technical success rate was 91% (50/55 patients). Procedural complications were encountered with six patients (11%). Angiographic and clinical follow-up data were available for 51 patients (93%), with a mean follow-up period of 28.1 months. No rebleedings were encountered during the study period. The clinical outcome was favorable in 50 patients (91%), with a Glasgow Outcome Score of 4 (N = 14) or 5 (N = 36) at the end of the study period. Poor clinical outcome correlated with very large (>2 cm) total aneurysm size (P = 0.002), large (>10 mm) recurrent aneurysm size (P = 0.011), and occurrence of periprocedural complications (P < 0.001). CONCLUSION: Stent-assisted coil embolization is beneficial for the retreatment of wide-necked recurrent or residual intracranial aneurysms, but stability and permanent occlusion of the recurrent aneurysm is unlikely if the aneurysm exceeds 2 cm in diameter, the recurrent diameter of the aneurysm exceeds 10 mm, or if mass effect is present with the recurrent aneurysm.

Observed heterospecific clutch size can affect offspring investment decisions.

Optimal investment in offspring is important in maximizing lifetime reproductive success. Yet, very little is known how animals gather and integrate information about environmental factors to fine tune investment. Observing the decisions and success of other individuals, particularly when those individuals initiate breeding earlier, may provide a way for animals to quickly arrive at better breeding investment decisions. Here we show, with a field experiment using artificial nests appearing similar to resident tit nests with completed clutches, that a migratory bird can use the observed high and low clutch size of a resident competing bird species to increase and decrease clutch size and egg mass, accordingly. Our results demonstrate that songbirds can discriminate between high and low quantity of heterospecific eggs, and that social information can have long-term physiological consequences affecting reproductive strategies. Such behaviour may help animals to better adapt to changing environments and lead to convergent traits with competitors.

The silk flow-diverting stent in the endovascular treatment of complex intracranial aneurysms: technical aspects and midterm results in 24 consecutive patients.

BACKGROUND: The flow-diverting stent is a new option in endovascular therapy specifically designed for the endovascular reconstruction of a segmentally diseased artery. The safety of flow-diverting stents is still equivocal. OBJECTIVE: To evaluate the technical aspects, thromboembolic events, adjunctive therapies, and midterm results in patients with complex intracranial aneurysms treated with a flow-diverting stent (Silk; Balt Extrusion, Montmorency, France). METHODS: We retrospectively examined angiographic images and clinical reports of 24 consecutive patients (29 stents) treated (n = 23) or attempted to treat (n = 1) with a flow-diverting device in 2 Finnish centers between March 2009 and October 2010. RESULTS: The primary technical success rate was 67% (16/24). Adjunctive therapies were required in 6 (25%) patients, including 4 cases where intra-arterial abciximab was administered for the treatment of intraprocedural thromboembolic events. Technique-related complication rate and the 30-day mortality rate were each 4% (1/24). Follow-up imaging revealed 1 case of delayed in-stent thrombosis resulting in permanent disability of the patient, 1 asymptomatic occlusion, and 1 asymptomatic stenosis of the stented artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 16 of the 23 aneurysms (70%) where follow-up images were available. CONCLUSION: Many previously untreatable cerebral aneurysms may be successfully treated with the Silk flow-diverting stent, but the associated risk of thromboembolic events is justifiable only if conventional endovascular or surgical treatment options are not applicable. Perioperative thromboembolic events should be prepared for and treated without unnecessary delays because they frequently respond to adjunctive medical therapy.