Niche modeling reveals life history shifts in birds at La Brea over the last twenty millennia

A species presence at a particular site can change over time, resulting in temporally dynamic species pools. Ecological niche models provide estimates of species presence at different time intervals. The avifauna of La Brea includes approximately 120 species dating to approximately 15,000 years ago. Niche models predicted presence at the Last Glacial Maximum for over 90% of 89 landbird species. This confirms that niche modeling produces sensible range estimates at the Last Glacial Maximum. For 97 currently local species that are as yet undocumented at La Brea over 90% were predicted to occur; absence is due to insufficient study, lack of the ecological niche, transient occurrence or a behavioral ability to avoid entrapment. Our 366 niche models provide a prospective checklist of the landbird fauna of La Brea. The models indicate fluidity in life history strategies and a higher proportion of resident birds at the LGM (88% to 60%). We evaluated a subset of 103 species in breeding and winter periods using two climate models (MIROC−ESM, CCSM4) with a variety of differing parameters, finding differences in 5% of the niche models. Niche breadths in bark-foraging birds changed little between the present and LGM, suggesting that greater species diversity at the LGM was due to greater niche availability rather than contractions of niche breadths (i.e., niche partitioning)

General anesthesia versus conscious sedation in mechanical thrombectomy

BACKGROUND AND PURPOSE Anesthesia regimen in patients undergoing mechanical thrombectomy (MT) is still an unresolved issue. METHODS We compared the effect of anesthesia regimen using data from the German Stroke Registry-Endovascular Treatment (GSR-ET) between June 2015 and December 2019. Degree of disability was rated by the modified Rankin Scale (mRS), and good outcome was defined as mRS 0-2. Successful reperfusion was assumed when the modified thrombolysis in cerebral infarction scale was 2b-3. RESULTS Out of 6,635 patients, 67.1% (n=4,453) patients underwent general anesthesia (GA), 24.9% (n=1,650) conscious sedation (CS), and 3.3% (n=219) conversion from CS to GA. Rate of successful reperfusion was similar across all three groups (83.0% vs. 84.2% vs. 82.6%, P=0.149). Compared to the CA-group, the GA-group had a delay from admission to groin (71.0 minutes vs. 61.0 minutes, P\textless0.001), but a comparable interval from groin to flow restoration (41.0 minutes vs. 39.0 minutes). The CS-group had the lowest rate of periprocedural complications (15.0% vs. 21.0% vs. 28.3%, P\textless0.001). The CS-group was more likely to have a good outcome at follow-up (42.1% vs. 34.2% vs. 33.5%, P\textless0.001) and a lower mortality rate (23.4% vs. 34.2% vs. 26.0%, P\textless0.001). In multivariable analysis, GA was associated with reduced achievement of good functional outcome (odds ratio OR, 0.82; 95{\%} confidence interval CI, 0.71 to 0.94; P=0.004) and increased mortality (OR, 1.42; 95{\%} CI, 1.23 to 1.64; P{\textless}0.001). Subgroup analysis for anterior circulation strokes (n=5,808) showed comparable results. CONCLUSIONS We provide further evidence that CS during MT has advantages over GA in terms of complications, time intervals, and functional outcome

Enhanced Electron Pairing in a Lattice of Berry Phase Molecules

We show that electron hopping in a lattice of molecules possessing a Berry phase naturally leads to pairing. Our building block is a simple molecular site model inspired by C$_{60}$, but realized in closer similarity with Na$_3$. In the resulting model electron hopping must be accompanied by orbital operators, whose function is to switch on and off the Berry phase as the electron number changes. The effective hamiltonians (electron-rotor and electron-pseudospin) obtained in this way are then shown to exhibit a strong pairing phenomenon, by means of 1D linear chain case studies. This emerges naturally from numerical studies of small $N$-site rings, as well as from a BCS-like mean-field theory formulation. The pairing may be explained as resulting from the exchange of singlet pairs of orbital excitations, and is intimately connected with the extra degeneracy implied by the Berry phase when the electron number is odd. The relevance of this model to fullerides, to other molecular superconductors, as well as to present and future experiments, is discussed.Comment: 30 pages, RevTe

CT after interhospital transfer in acute ischemic stroke: Imaging findings and impact of prior intravenous contrast administration

Objectives: Large vessel occlusion (LVO) stroke patients routinely undergo interhospital transfer to endovascular thrombectomy capable centers. Imaging is often repeated with residual intravenous (IV) iodine contrast at post-transfer assessment. We determined imaging findings and the impact of residual contrast on secondary imaging. Anterior circulation LVO stroke patients were selected out of a consecutive cohort. Directly admitted patients were contrast naïve, and transferred patients had previously received IV iodine contrast for stroke assessment at the referring hospital. Two independent readers rated the visibility of residual contrast on non-contrast computed tomography (CT) after transfer and assessed the hyperdense vessel sign. Multivariate linear regression analysis was used to investigate the association of the Alberta Stroke Program Early CT score (ASPECTS) with prior contrast administration, time from symptom onset (TFSO), and CTP ischemic core volume in both directly admitted and transferred patients. Results: We included 161 patients, with 62 (39%) transferred and 99 (62%) directly admitted patients. Compared between these groups, transferred patients had a longer TFSO-to-imaging at our institution (median: 212 vs. 75 min, p < 0.001) and lower ASPECTS (median: 8 vs. 9, p < 0.001). Regression analysis presented an independent association of ASPECTS with prior contrast administration (β = −0.25, p = 0.004) but not with TFSO (β = −0.03, p = 0.65). Intergroup comparison between transferred and directly admitted patients pointed toward a stronger association between ASPECTS and CTP ischemic core volume in transferred patients (β = −0.39 vs. β = −0.58, p = 0.06). Detectability of the hyperdense vessel sign was substantially lower after transfer (66 vs. 10%, p < 0.001). Conclusion: Imaging alterations due to residual IV contrast are frequent in clinical practice and render the hyperdense vessel sign largely indetectable. Larger studies are needed to clarify the influence on the association between ASPECTS and ischemic core

Staphylococcus aureus α-Toxin Triggers the Synthesis of B-Cell Lymphoma 3 by Human Platelets

The frequency and severity of bacteremic infections has increased over the last decade and bacterial endovascular infections (i.e., sepsis or endocarditis) are associated with high morbidity and mortality. Bacteria or secreted bacterial products modulate platelet function and, as a result, affect platelet accumulation at sites of vascular infection and inflammation. However, whether bacterial products regulate synthetic events in platelets is not known. In the present study, we determined if prolonged contact with staphylococcal α-toxin signals platelets to synthesize B-cell lymphoma (Bcl-3), a protein that regulates clot retraction in murine and human platelets. We show that α-toxin induced αIIbβ3-dependent aggregation (EC50 2.98 µg/mL ± 0.64 µg/mL) and, over time, significantly altered platelet morphology and stimulated de novo accumulation of Bcl-3 protein in platelets. Adherence to collagen or fibrinogen also increased the expression of Bcl-3 protein by platelets. α-toxin altered Bcl-3 protein expression patterns in platelets adherent to collagen, but not fibrinogen. Pretreatment of platelets with inhibitors of protein synthesis or the mammalian Target of Rapamycin (mTOR) decreased Bcl-3 protein expression in α-toxin stimulated platelets. In conclusion, Staphylococcus aureus-derived α-toxin, a pore forming exotoxin, exerts immediate (i.e., aggregation) and prolonged (i.e., protein synthesis) responses in platelets, which may contribute to increased thrombotic events associated with gram-positive sepsis or endocarditis

Tau, prions and Aβ: the triad of neurodegeneration

This article highlights the features that connect prion diseases with other cerebral amyloidoses and how these relate to neurodegeneration, with focus on tau phosphorylation. It also discusses similarities between prion disease and Alzheimer’s disease: mechanisms of amyloid formation, neurotoxicity, pathways involved in triggering tau phosphorylation, links to cell cycle pathways and neuronal apoptosis. We review previous evidence of prion diseases triggering hyperphosphorylation of tau, and complement these findings with cases from our collection of genetic, sporadic and transmitted forms of prion diseases. This includes the novel finding that tau phosphorylation consistently occurs in sporadic CJD, in the absence of amyloid plaques

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Niche modeling reveals life history shifts in birds at La Brea over the last twenty millennia

A species presence at a particular site can change over time, resulting in temporally dynamic species pools. Ecological niche models provide estimates of species presence at different time intervals. The avifauna of La Brea includes approximately 120 species dating to approximately 15,000 years ago. Niche models predicted presence at the Last Glacial Maximum for over 90% of 89 landbird species. This confirms that niche modeling produces sensible range estimates at the Last Glacial Maximum. For 97 currently local species that are as yet undocumented at La Brea over 90% were predicted to occur; absence is due to insufficient study, lack of the ecological niche, transient occurrence or a behavioral ability to avoid entrapment. Our 366 niche models provide a prospective checklist of the landbird fauna of La Brea. The models indicate fluidity in life history strategies and a higher proportion of resident birds at the LGM (88% to 60%). We evaluated a subset of 103 species in breeding and winter periods using two climate models (MIROC−ESM, CCSM4) with a variety of differing parameters, finding differences in 5% of the niche models. Niche breadths in bark-foraging birds changed little between the present and LGM, suggesting that greater species diversity at the LGM was due to greater niche availability rather than contractions of niche breadths (i.e., niche partitioning)