89 research outputs found
Brief increases in corticosterone affect morphology, stress responses, and telomere length, but not post-fledging movements, in a wild songbird
Organisms are frequently exposed to challenges during development, such as
poor weather and food shortage. Such challenges can initiate the hormonal
stress response, which involves secretion of glucocorticoids. Although the
hormonal stress response helps organisms deal with challenges, long-term
exposure to high levels of glucocorticoids can have morphological, behavioral,
and physiological consequences, especially during development. Glucocorticoids
are also associated with reduced survival and telomere shortening. To
investigate whether brief, acute exposures to glucocorticoids can also produce
these phenotypic effects in free-living birds, we exposed wild tree swallow
(Tachycineta bicolor) nestlings to a brief exogenous dose of cort once per day
for five days and then measured their morphology, baseline and stress-induced
corticosterone levels, and telomere length. We also deployed radio tags on a
subset of nestlings, which allowed us to determine the age at which tagged
nestlings left the nest (fledged) and their pattern of presence and absence at
the natal site during the post-breeding period. Corticosterone-treated
nestlings had lower mass, higher baseline and stress-induced corticosterone,
and reduced telomeres; other metrics of morphology were affected weakly or not
at all. Our treatment resulted in no significant effect on survival to
fledging, fledge age, or age at first departure from the natal site, and we
found no negative effect of corticosterone on inter-annual return rate. These
results show that brief acute corticosterone exposure during development can
have measurable effects on phenotype in free-living tree swallows.
Corticosterone may therefore mediate correlations between rearing environment
and phenotype in developing organisms, even in the absence of prolonged
stressors.Comment: 35 pages, 4 figures, 1 appendi
Collaboration between education and health professionals for the assessment of speech development
Im Spannungsfeld Kita, Schule und Sprachtherapie ist multifaktorielle Expertise gefragt, um sprachliche FĂ€higkeiten von Kindern einzuschĂ€tzen und gegebenenfalls geeignete Förder- oder TherapiemaĂnahmen abzuleiten. Eine besondere Herausforderung stellt dabei die strukturelle KomplexitĂ€t der Versorgung hinsichtlich der verschiedenen Akteur*innen, Organisationen und Versorgungssysteme dar. Ziel der Studie war es, in Form einer Kontextanalyse die interprofessionellen Prozesse und Strukturen bzgl. kindlicher Sprachentwicklung zu rekonstruieren sowie fördernde und hemmende Faktoren zu identifizieren. Es wurden fĂŒnf Fokusgruppen mit jeweils drei Expert*innen aus den Berufsgruppen Erzieher*in, Sprachtherapeut*in, (Grundschul-)Lehrer*in, SonderpĂ€dagog*in und Mediziner*in durchgefĂŒhrt und ausgewertet, wobei auf die Methode der qualitativen Inhaltsanalyse mittels Extraktion zurĂŒckgegriffen wurde. Aus den Analysen ergab sich, dass personelle und ökonomische Ressourcen sowie klar kommunizierte rechtliche Rahmenbedingungen auf Systemebene eine Rolle spielen. Organisationsbezogen konnte die Gestaltung der Kommunikations- und Dokumentationsprozesse als wesentlicher Faktor fĂŒr das Gelingen interprofessioneller Zusammenarbeit identifiziert werden. Das Engagement der Akteur*innen und der adĂ€quate Einbezug von Erziehungsberechtigten sind ebenfalls als Einflussfaktor zu nennen. Die Expert*innen sehen ein hohes Potential in interprofessioneller Zusammenarbeit. Eine solche Zusammenarbeit ist ihrer Ansicht nach besonders wertvoll, wenn es um die QualitĂ€t der Beurteilung des kindlichen (Sprach-)Entwicklungsstandes (1) und der Förder- und Therapieangebote (2) geht. Es besteht ein Bedarf an der Gestaltung interprofessioneller Netzwerke ĂŒber eine zentrale, sichere, niedrigschwellige und digitale Dokumentations- und Austauschplattform fĂŒr die fallzentrierte Zusammenarbeit. (DIPF/Orig.)Across daycare, school and speech and language therapy (SLT), multifactorial expertise is required to assess the language skills of children and, if necessary, define suitable support or therapeutical measures. The structural complexity of health care, welfare and public education involving various stakeholders, organisations and care systems poses a particular challenge. The aim of the study was a context analysis to reconstruct interprofessional processes and structures with regard to childrenâs language development and to identify promoting and inhibiting factors. Five focus group interviews, involving three experts each, were conducted and analysed, using the method of qualitative content analysis by means of extraction. The analyses showed that staff and economic resources as well as clearly communicated legal framework conditions play a role at the system level. In terms of organisation, the nature of communication and documentation processes was identified as an essential factor for the success of interprofessional cooperation. The commitment of stakeholders and the adequate involvement of caregivers can also be mentioned as an influencing factor. The participants see high value in interprofessional cooperation. Such cooperation, in their view, is particularly valuable when it comes to the quality of the assessment of the language development of children (1) and of the support and therapy services (2). This study thus suggests that there is a need to create and sustain interprofessional networks through a central, secure, low-threshold and digital documentation and exchange platform for case-centred cooperation. (DIPF/Orig.
Terminal spreading depolarization and electrical silence in death of human cerebral cortex
Objective: Restoring the circulation is the primary goal in emergency
treatment of cerebral ischemia. However, better understanding of how the brain
responds to energy depletion could help predict the time available for
resuscitation until irreversible damage and advance development of
interventions that prolong this span. Experimentally, injury to central
neurons begins only with anoxic depolarization. This potentially reversible,
spreading wave typically starts 2 to 5 minutes after the onset of severe
ischemia, marking the onset of a toxic intraneuronal change that eventually
results in irreversible injury. Methods: To investigate this in the human
brain, we performed recordings with either subdural electrode strips (nâ=â4)
or intraparenchymal electrode arrays (nâ=â5) in patients with devastating
brain injury that resulted in activation of a Do Not ResuscitateâComfort Care
order followed by terminal extubation. Results: Withdrawal of lifeâsustaining
therapies produced a decline in brain tissue partial pressure of oxygen
(ptiO2) and circulatory arrest. Silencing of spontaneous electrical activity
developed simultaneously across regional electrode arrays in 8 patients. This
silencing, termed ânonspreading depression,â developed during the steep
falling phase of ptiO2 (intraparenchymal sensor, nâ=â6) at 11 (interquartile
range [IQR]â=â7â14) mmHg. Terminal spreading depolarizations started to
propagate between electrodes 3.9 (IQRâ=â2.6â6.3) minutes after onset of the
final drop in perfusion and 13 to 266 seconds after nonspreading depression.
In 1 patient, terminal spreading depolarization induced the initial
electrocerebral silence in a spreading depression pattern; circulatory arrest
developed thereafter. Interpretation: These results provide fundamental
insight into the neurobiology of dying and have important implications for
survivable cerebral ischemic insults. Ann Neurol 2018;83:295â31
Correlation of velocity and susceptibility in patients with aneurysmal subarachnoid hemorrhage
In many cerebral grey matter structures including the neocortex, spreading
depolarization (SD) is the principal mechanism of the near-complete breakdown
of the transcellular ion gradients with abrupt water influx into neurons.
Accordingly, SDs are abundantly recorded in patients with traumatic brain
injury, spontaneous intracerebral hemorrhage, aneurysmal subarachnoid
hemorrhage (aSAH) and malignant hemispheric stroke using subdural electrode
strips. SD is observed as a large slow potential change, spreading in the
cortex at velocities between 2 and 9 mm/min. Velocity and SD susceptibility
typically correlate positively in various animal models. In patients monitored
in neurocritical care, the Co-Operative Studies on Brain Injury
Depolarizations (COSBID) recommends several variables to quantify SD
occurrence and susceptibility, although accurate measures of SD velocity have
not been possible. Therefore, we developed an algorithm to estimate SD
velocities based on reconstructing SD trajectories of the wave-front's
curvature center from magnetic resonance imaging scans and time-of-SD-arrival-
differences between subdural electrode pairs. We then correlated variables
indicating SD susceptibility with algorithm-estimated SD velocities in twelve
aSAH patients. Highly significant correlations supported the algorithm's
validity. The trajectory search failed significantly more often for SDs
recorded directly over emerging focal brain lesions suggesting in humans
similar to animals that the complexity of SD propagation paths increase in
tissue undergoing injury
Spreading depolarization and angiographic spasm are separate mediators of delayed infarcts
In DISCHARGE-1, a recent Phase III diagnostic trial in aneurysmal subarachnoid haemorrhage patients, spreading depolarization variables were found to be an independent real-time biomarker of delayed cerebral ischaemia. We here investigated based on prospectively collected data from DISCHARGE-1 whether delayed infarcts in the anterior, middle, or posterior cerebral artery territories correlate with (i) extravascular blood volumes; (ii) predefined spreading depolarization variables, or proximal vasospasm assessed by either (iii) digital subtraction angiography or (iv) transcranial Doppler-sonography; and whether spreading depolarizations and/or vasospasm are mediators between extravascular blood and delayed infarcts. Relationships between variable groups were analysed using Spearman correlations in 136 patients. Thereafter, principal component analyses were performed for each variable group. Obtained components were included in path models with a priori defined structure. In the first path model, we only included spreading depolarization variables, as our primary interest was to investigate spreading depolarizations. Standardised path coefficients were 0.22 for the path from extravascular bloodcomponent to depolarizationcomponent (P = 0.010); and 0.44 for the path from depolarizationcomponent to the first principal component of delayed infarct volume (P < 0.001); but only 0.07 for the direct path from bloodcomponent to delayed infarctcomponent (P = 0.36). Thus, the role of spreading depolarizations as a mediator between blood and delayed infarcts was confirmed. In the principal component analysis of extravascular blood volume, intraventricular haemorrhage was not represented in the first component. Therefore, based on the correlation analyses, we also constructed another path model with bloodcomponent without intraventricular haemorrhage as first and intraventricular haemorrhage as second extrinsic variable. We found two paths, one from (subarachnoid) bloodcomponent to delayed infarctcomponent with depolarizationcomponent as mediator (path coefficients from bloodcomponent to depolarizationcomponent = 0.23, P = 0.03; path coefficients from depolarizationcomponent to delayed infarctcomponent = 0.29, P = 0.002), and one from intraventricular haemorrhage to delayed infarctcomponent with angiographic vasospasmcomponent as mediator variable (path coefficients from intraventricular haemorrhage to vasospasmcomponent = 0.24, P = 0.03; path coefficients from vasospasmcomponent to delayed infarctcomponent = 0.35, P < 0.001). Human autopsy studies shaped the hypothesis that blood clots on the cortex surface suffice to cause delayed infarcts beneath the clots. Experimentally, clot-released factors induce cortical spreading depolarizations that trigger (i) neuronal cytotoxic oedema and (ii) spreading ischaemia. The statistical mediator role of spreading depolarization variables between subarachnoid blood volume and delayed infarct volume supports this pathogenetic concept. We did not find that angiographic vasospasm triggers spreading depolarizations, but angiographic vasospasm contributed to delayed infarct volume. This could possibly result from enhancement of spreading depolarization-induced spreading ischaemia by reduced upstream blood supply.Peer Reviewe
Argatroban versus heparin in patients without heparin-induced thrombocytopenia during venovenous extracorporeal membrane oxygenation: a propensity-score matched study
Abstract
Background
During venovenous extracorporeal membrane oxygenation (vvECMO), direct thrombin inhibitors are considered by some potentially advantageous over unfractionated heparin (UFH). We tested the hypothesis that Argatroban is non-inferior to UFH regarding thrombosis and bleeding during vvECMO.
Methods
We conducted a propensity-score matched observational non-inferiority study of consecutive patients without heparin-induced-thrombocytopenia (HIT) on vvECMO, treated between January 2006 and March 2019 in the medical intensive care unit at the University Hospital Regensburg. Anticoagulation was realized with UFH until August 2017 and with Argatroban from September 2017 onwards. Target activated partial thromboplastin time was 50â±â5seconds in both groups. Primary composite endpoint was major thrombosis and/or major bleeding. Major bleeding was defined as a drop in hemoglobin ofââ„â2 g/dl/day or in transfusion ofââ„â2 packed red cells/24 h, or retroperitoneal, cerebral, or pulmonary bleeding. Major thrombosis was defined as obstruction ofâ>â50% of the vessel lumen diameter by means of duplex sonography. We also assessed technical complications such as oxygenator defects or pump head thrombosis, the time-course of platelets, and the cost of anticoagulation (including HIT-testing).
Results
Out of 465 patients receiving UFH, 78 were matched to 39 patients receiving Argatroban. The primary endpoint occurred in 79% of patients in the Argatroban group and in 83% in the UFH group (non-inferiority for Argatroban, pâ=â0.026). The occurrence of technical complications was equally distributed (Argatroban 49% vs. UFH 42%, pâ=â0.511). The number of platelets was similar in both groups before ECMO therapy but lower in the UFH group after end of ECMO support (median [IQR]: 141 [104;198]/nl vs. 107 [54;171]/nl, pâ=â0.010). Anticoagulation costs per day of ECMO were higher in the Argatroban group (âŹ26 [13.8;53.0] vs. âŹ0.9 [0.5;1.5], pâ<â0.001) but not after accounting for blood products and HIT-testing (âŹ63 [42;171) vs. âŹ40 [17;158], pâ=â0.074).
Conclusion
In patients without HIT on vvECMO, Argatroban was non-inferior to UFH regarding bleeding and thrombosis. The occurrence of technical complications was similarly distributed. Argatroban may have less impact on platelet decrease during ECMO, but this finding needs further evaluation. Direct drug costs were higher for Argatroban but comparable to UFH after accounting for HIT-testing and transfusions
Full lifetime perspectives on the costs and benefits of lay date variation in tree swallows
Animals must balance various costs and benefits when deciding when to breed. The costs and benefits of breeding at different times have received much attention, but most studies have been limited to investigating short-term season-to-season fitness effects. However, breeding early, versus late, in a season may influence lifetime fitness over many years, trading off in complex ways across the breeder?s lifepan. In this study, we examined the complete life histories of 867 female tree swallows (Tachycineta bicolor) breeding in Ithaca, New York, between 2002 and 2016. Earlier breeders outperformed later breeders in short-term measures of reproductive output and offspring quality. Though there were weak indications that females paid long-term future survival costs for breeding early, lifetime fledgling output was markedly higher overall in early-breeding birds. Importantly, older females breeding later in the season did not experience compensating life-history advantages that suggested an alternative equal-fitness breeding strategy. Rather, most or all of the swallows appear to be breeding as early as they can, and differences in lay dates appear to be determined primarily by differences in individual quality or condition. Lay date had a significant repeatability across breeding attempts by the same female, and the first lay date of females fledged in our population was strongly influenced by the first lay date of their mothers, indicating the potential for ongoing selection on lay date. By examining performance over the entire lifespan of a large number of individuals, we were able to clarify the relationship between timing of breeding and fitness and gain new insight into the sources of variability in this important life history trait.Fil: Winkler, David Ward. Cornell University; Estados UnidosFil: Hallinger, Kelly K.. Cornell University; Estados UnidosFil: Pegan, Teresa M.. University of Michigan; Estados UnidosFil: Taff, Conor C.. Cornell University; Estados UnidosFil: Verhoeven, Mo A.. University of Groningen; PaĂses BajosFil: Van Oordt, David Chang. Cornell University; Estados UnidosFil: Stager, Maria. University of Montana; Estados UnidosFil: Uehling, Jennifer J.. Cornell University; Estados UnidosFil: Vitousek, Maren N.. Cornell University; Estados UnidosFil: Andersen, Michael J.. University of New Mexico; Estados UnidosFil: Ardia, Daniel R.. Franklin & Marshall College; Estados UnidosFil: Belmaker, Amos. Tel Aviv University; IsraelFil: Ferretti, Valentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de EcologĂa, GenĂ©tica y EvoluciĂłn de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de EcologĂa, GenĂ©tica y EvoluciĂłn de Buenos Aires; ArgentinaFil: Forsman, Anna M.. University Of Central Florida; Estados UnidosFil: Gaul, Jennifer R.. International High School at La Guardia Community College; Estados UnidosFil: Llambias, Paulo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Ăridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Ăridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Ăridas; ArgentinaFil: Orzechowski, Sophia C.. Harvard University; Estados UnidosFil: Shipley, Ryan. Max Planck Institute For Animal Behavior; AlemaniaFil: Wilson, Maya. Virginia Polytechnic Institute. Department Of Geological Sciences; Estados UnidosFil: Yoon, Hyun Seok. University of Tennessee; Estados Unido
Extrinsic immune cell-derived, but not intrinsic oligodendroglial factors contribute to oligodendroglial differentiation block in multiple sclerosis
Abstract
Multiple sclerosis (MS) is the most frequent demyelinating disease in young adults and despite significant advances in immunotherapy, disease progression still cannot be prevented. Promotion of remyelination, an endogenous repair mechanism resulting in the formation of new myelin sheaths around demyelinated axons, represents a promising new treatment approach. However, remyelination frequently fails in MS lesions, which can in part be attributed to impaired differentiation of oligodendroglial progenitor cells into mature, myelinating oligodendrocytes. The reasons for impaired oligodendroglial differentiation and defective remyelination in MS are currently unknown. To determine whether intrinsic oligodendroglial factors contribute to impaired remyelination in relapsingâremitting MS (RRMS), we compared induced pluripotent stem cell-derived oligodendrocytes (hiOL) from RRMS patients and controls, among them two monozygous twin pairs discordant for MS. We found that hiOL from RRMS patients and controls were virtually indistinguishable with respect to remyelination-associated functions and proteomic composition. However, while analyzing the effect of extrinsic factors we discovered that supernatants of activated peripheral blood mononuclear cells (PBMCs) significantly inhibit oligodendroglial differentiation. In particular, we identified CD4+ T cells as mediators of impaired oligodendroglial differentiation; at least partly due to interferon-gamma secretion. Additionally, we observed that blocked oligodendroglial differentiation induced by PBMC supernatants could not be restored by application of oligodendroglial differentiation promoting drugs, whereas treatment of PBMCs with the immunomodulatory drug teriflunomide prior to supernatant collection partly rescued oligodendroglial differentiation. In summary, these data indicate that the oligodendroglial differentiation block is not due to intrinsic oligodendroglial factors but rather caused by the inflammatory environment in RRMS lesions which underlines the need for drug screening approaches taking the inflammatory environment into account. Combined, these findings may contribute to the development of new remyelination promoting strategies
Interferometric Single-Shot Parity Measurement in an InAs-Al Hybrid Device
The fusion of non-Abelian anyons or topological defects is a fundamental
operation in measurement-only topological quantum computation. In topological
superconductors, this operation amounts to a determination of the shared
fermion parity of Majorana zero modes. As a step towards this, we implement a
single-shot interferometric measurement of fermion parity in indium
arsenide-aluminum heterostructures with a gate-defined nanowire. The
interferometer is formed by tunnel-coupling the proximitized nanowire to
quantum dots. The nanowire causes a state-dependent shift of these quantum
dots' quantum capacitance of up to 1 fF. Our quantum capacitance measurements
show flux h/2e-periodic bimodality with a signal-to-noise ratio of 1 in 3.7
s at optimal flux values. From the time traces of the quantum capacitance
measurements, we extract a dwell time in the two associated states that is
longer than 1 ms at in-plane magnetic fields of approximately 2 T. These
results are consistent with a measurement of the fermion parity encoded in a
pair of Majorana zero modes that are separated by approximately 3 m and
subjected to a low rate of poisoning by non-equilibrium quasiparticles. The
large capacitance shift and long poisoning time enable a parity measurement
error probability of 1%.Comment: Added data on a second measurement of device A and a measurement of
device B, expanded discussion of a trivial scenario. Refs added, author list
update
Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research
No abstract available
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