100 research outputs found
Simultaneous dynamic glucose-enhanced (DGE) MRI and fiber photometry measurements of glucose in the healthy mouse brain
Glucose is the main energy source in the brain and its regulated uptake and utilization are important biomarkers of pathological brain function. Glucose Chemical Exchange Saturation Transfer (GlucoCEST) and its time-resolved version Dynamic Glucose-Enhanced MRI (DGE) are promising approaches to monitor glucose and detect tumors, since it is radioactivity-free, does not require 13C labelling and it is easily translatable to the clinics. The main principle of DGE is clear. However, what remains to be established is to which extent the signal reflects vascular, extracellular or intracellular glucose. To elucidate the compartmental contributions to the DGE signal, we coupled it with FRET-based fiber photometry of genetically encoded sensors, a technique that combines quantitative glucose readout with cellular specificity. The glucose sensor FLIIP was used with fiber photometry to measure astrocytic and neuronal glucose changes upon injection of D-glucose, 3OMG and L-glucose, in the anaesthetized murine brain. By correlating the kinetic profiles of the techniques, we demonstrate the presence of a vascular contribution to the signal, especially at early time points after injection. Furthermore, we show that, in the case of the commonly used contrast agent 3OMG, the DGE signal actually anticorrelates with the glucose concentration in neurons and astrocytes.
Keywords: fiber photometry; genetically encoded sensors; glucoCEST; kinetic modelling; two-photon microscopy
Variation of blubber thickness for three marine mammal species in the southern Baltic Sea
Evaluating populational trends of health condition has become an important
topic for marine mammal populations under the Marine Strategy Framework
Directive (MSFD). In the Baltic Sea, under the recommendation of Helsinki
Commission (HELCOM), efforts have been undertaken to use blubber thickness
as an indicator of energy reserves in marine mammals. Current values lack
geographical representation from the entire Baltic Sea area and a large dataset is
only available for grey seals (Halichoerus grypus) from Sweden and Finland.
Knowledge on variation of blubber thickness related to geography throughout
the Baltic Sea is important for its usage as an indicator. Such evaluation can
provide important information about the energy reserves, and hence, food
availability. It is expected that methodological standardization under HELCOM
should include relevant datasets with good geographical coverage that can also
account for natural variability in the resident marine mammal populations. In
this study, seasonal and temporal trends of blubber thickness were evaluated for
three marine mammal species—harbor seal (Phoca vitulina), grey seal
(Halichoerus grypus) and harbor porpoise (Phocoena phocoena)—resident in
the southern Baltic Sea collected and investigated under stranding networks.
Additionally, the effects of age, season and sex were analyzed. Seasonal
variation of blubber thickness was evident for all species, with harbor seals
presenting more pronounced effects in adults and grey seals and harbor
porpoises presenting more pronounced effects in juveniles. For harbor seals
and porpoises, fluctuations were present over the years included in the analysis.
In the seal species, blubber thickness values were generally higher in males. In
harbor seals and porpoises, blubber thickness values differed between the age
classes: while adult harbor seals displayed thicker blubber layers than juveniles,
the opposite was observed for harbor porpoises. Furthermore, while an
important initial screening tool, blubber thickness assessment cannot be
considered a valid methodology for overall health assessment in marine
mammals and should be complemented with data on specific health
parameters developed for each speciesinfo:eu-repo/semantics/publishedVersio
Forschungsprojekte mit der Praxis entwickeln: Ergebnisse des Projektentwicklungsprozesses der Innovationsgruppe ginkoo
Organic farming actors need to handle more complex innovation processes to develop locally adapted and globally relevant solutions for challenges such as agricultural-biodiversity and relationship between farmers and producers. For a coordinating management of such innovation processes, management tools that exceed classical innovation management techniques, are required if sustainable solutions are to be achieved. Developing relevant knowledge requires a transdisciplinary approach to bridge the gap between science and practice. This paper presents our process and the resulting concept of the transdisciplinary innovation group ginkoo for one of two case studies. It aims at developing a research concept that integrates the practical context such that ground for using the research findings after the end of funding has been laid
Spatiotemporal mortality and demographic trends in a small cetacean: Strandings to inform conservation management
With global increases in anthropogenic pressures on wildlife populations comes a responsibility to manage them effectively. The assessment of marine ecosystem health is challenging and often relies on monitoring indicator species, such as cetaceans. Most cetaceans are however highly mobile and spend the majority of their time hidden from direct view, resulting in uncertainty on even the most basic population metrics. Here, we discuss the value of long-term and internationally combined stranding records as a valuable source of information on the demographic and mortality trends of the harbour porpoise (Phocoena phocoena) in the North Sea. We analysed stranding records (n = 16,181) from 1990 to 2017 and demonstrate a strong heterogeneous seasonal pattern of strandings throughout the North Sea, indicative of season-specific distribution or habitat use, and season-specific mortality. The annual incidence of strandings has increased since 1990, with a notable steeper rise particularly in the southern North Sea since 2005. A high density of neonatal strandings occurred specifically in the eastern North Sea, indicative of areas important for calving, and large numbers of juvenile males stranded in the southern parts, indicative of a population sink or reflecting higher male dispersion. These findings highlight the power of stranding records to detect potentially vulnerable population groups in time and space. This knowledge is vital for managers and can guide, for example, conservation measures such as the establishment of time-area-specific limits to potentially harmful human activities, aiming to reduce the number and intensity of human-wildlife conflicts
Menschen schützen und unterstützen: warum Solidarität weiterhin gefragt ist in der Pandemie
Seit Beginn der Pandemie hat sich unser Fachwissen sowohl über die Ausbreitung des Virus als auch über Präventionsmaßnahmen vervielfacht. Tests, Impfungen und Therapien sind verfügbar und viele Fragestellungen durch die Erkenntnisse der letzten Jahre gelöst worden. Trotzdem bleibt die Entscheidungsfindung für Interventionen im Sinne der öffentlichen Gesundheit weiterhin eine Herausforderung. Dafür kann die unabhängige und interdisziplinäre Wissenschaft weiterhin wichtige Impulse setzen und Perspektiven liefern. Dieses Papier stellt einige zentrale Punkte zusammen, die aus einem intensiven Diskursprozess entstanden sind, der in den letzten Monaten unter den angeführten Expert*innen und Wissenschafter*innen verschiedener Disziplinen stattgefunden hat. Es besteht der Grundkonsens, dass eine gesundheitspolitische und ethische Notwendigkeit besteht, den Schutz jener Menschen im Blick zu behalten, welche anfälliger für schwere COVID-19 Krankheitsverläufe, als auch Long Covid sind, sowie deren Umfeld und generell im Hinblick auf Gesundheitsfragen vorsichtig agierende Personen. Dieses Papier soll Bewusstsein für die Thematik stärken, und Entscheidungsträger:innen sensibilisieren und darin unterstützen, diese Personenkreise in ihren Überlegungen im Blick zu behalten
Drivers of soil microbial and detritivore activity across global grasslands
Covering approximately 40% of land surfaces, grasslands provide critical ecosystem services that rely on soil organisms. However, the global determinants of soil biodiversity and functioning remain underexplored. In this study, we investigate the drivers of soil microbial and detritivore activity in grasslands across a wide range of climatic conditions on five continents. We apply standardized treatments of nutrient addition and herbivore reduction, allowing us to disentangle the regional and local drivers of soil organism activity. We use structural equation modeling to assess the direct and indirect effects of local and regional drivers on soil biological activities. Microbial and detritivore activities are positively correlated across global grasslands. These correlations are shaped more by global climatic factors than by local treatments, with annual precipitation and soil water content explaining the majority of the variation. Nutrient addition tends to reduce microbial activity by enhancing plant growth, while herbivore reduction typically increases microbial and detritivore activity through increased soil moisture. Our findings emphasize soil moisture as a key driver of soil biological activity, highlighting the potential impacts of climate change, altered grazing pressure, and eutrophication on nutrient cycling and decomposition within grassland ecosystems
Drivers of soil microbial and detritivore activity across global grasslands
Covering approximately 40% of land surfaces, grasslands provide critical ecosystem services that rely on soil organisms. However, the global determinants of soil biodiversity and functioning remain underexplored. In this study, we investigate the drivers of soil microbial and detritivore activity in grasslands across a wide range of climatic conditions on five continents. We apply standardized treatments of nutrient addition and herbivore reduction, allowing us to disentangle the regional and local drivers of soil organism activity. We use structural equation modeling to assess the direct and indirect effects of local and regional drivers on soil biological activities. Microbial and detritivore activities are positively correlated across global grasslands. These correlations are shaped more by global climatic factors than by local treatments, with annual precipitation and soil water content explaining the majority of the variation. Nutrient addition tends to reduce microbial activity by enhancing plant growth, while herbivore reduction typically increases microbial and detritivore activity through increased soil moisture. Our findings emphasize soil moisture as a key driver of soil biological activity, highlighting the potential impacts of climate change, altered grazing pressure, and eutrophication on nutrient cycling and decomposition within grassland ecosystems.Additional authors: Johannes M. H. Knops, Andrew S. MacDougall, Rebecca L. McCulley, Joslin L. Moore, Sally A. Power, Jodi N. Price, Eric W. Seabloom, Rachel Standish, Carly J. Stevens, Stephan Zimmermann, Nico Eisenhaue
Lenalidomide in combination with dexamethasone at first relapse in comparison with its use as later salvage therapy in relapsed or refractory multiple myeloma
This subset analysis of data from two phase III studies in patients with relapsed or refractory multiple myeloma (MM) evaluated the benefit of initiating lenalidomide plus dexamethasone at first relapse. Multivariate analysis showed that fewer prior therapies, along with β2-microglobulin (≤2.5 mg/L), predicted a better time to progression (TTP; study end-point) with lenalidomide plus dexamethasone treatment. Patients with one prior therapy showed a significant improvement in benefit after first relapse compared with those who received two or more therapies. Patients with one prior therapy had significantly prolonged median TTP (17.1 vs. 10.6 months; P=0.026) and progression-free survival (14.1 vs. 9.5 months, P=0.047) compared with patients treated in later lines. Overall response rates were higher (66.9% vs. 56.8%, P=0.06), and the complete response plus very good partial response rate was significantly higher in first relapse (39.8% vs. 27.7%, P=0.025). Importantly, overall survival was significantly prolonged for patients treated with lenalidomide plus dexamethasone with one prior therapy, compared with patients treated later in salvage (median of 42.0 vs. 35.8 months, P=0.041), with no differences in toxicity, dose reductions, or discontinuations despite longer treatment. Therefore, lenalidomide plus dexamethasone is both effective and tolerable for second-line MM therapy and the data suggest that the greatest benefit occurs with earlier use
Insights on the Neuromagnetic Representation of Temporal Asymmetry in Human Auditory Cortex.
Communication sounds are typically asymmetric in time and human listeners are highly sensitive to this short-term temporal asymmetry. Nevertheless, causal neurophysiological correlates of auditory perceptual asymmetry remain largely elusive to our current analyses
and models. Auditory modelling and animal electrophysiological recordings suggest that perceptual asymmetry results from the presence of multiple time scales of temporal integration, central to the auditory periphery. To test this hypothesis we recorded auditory evoked fields (AEF) elicited by asymmetric sounds in humans. We found a strong correlation between perceived tonal salience of ramped and damped sinusoids and the AEFs, as quantified by the amplitude of the N100m dynamics. The N100m amplitude increased with stimulus
half-life time, showing a maximum difference between the ramped and damped stimulus for a modulation half-life time of 4 ms which is greatly reduced at 0.5 ms and 32 ms. This behaviour of the N100m closely parallels psychophysical data in a manner that: i) longer
half-life times are associated with a stronger tonal percept, and ii) perceptual differences between damped and ramped are maximal at 4 ms half-life time. Interestingly, differences in evoked fields were significantly stronger in the right hemisphere, indicating some degree of hemispheric specialisation. Furthermore, the N100m magnitude was successfully
explained by a pitch perception model using multiple scales of temporal integration of auditory
nerve activity patterns. This striking correlation between AEFs, perception, and model predictions suggests that the physiological mechanisms involved in the processing of pitch evoked by temporal asymmetric sounds are reflected in the N100m
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