A comparison of third-generation semi-invasive arterial waveform analysis with thermodilution in patients undergoing coronary surgery

Uncalibrated semi-invasive continous monitoring of cardiac index (CI) has recently gained increasing interest. The aim of the present study was to compare the accuracy of CI determination based on arterial waveform analysis with transpulmonary thermodilution. Fifty patients scheduled for elective coronary surgery were studied after induction of anaesthesia and before and after cardiopulmonary bypass (CPB), respectively. Each patient was monitored with a central venous line, the PiCCO system, and the FloTrac/Vigileo-system. Measurements included CI derived by transpulmonary thermodilution and uncalibrated semi-invasive pulse contour analysis. Percentage changes of CI were calculated. There was a moderate, but significant correlation between pulse contour CI and thermodilution CI both before (r(2) = 0.72, P < 0.0001) and after (r(2) = 0.62, P < 0.0001) CPB, with a percentage error of 31% and 25%, respectively. Changes in pulse contour CI showed a significant correlation with changes in thermodilution CI both before (r(2) = 0.52, P < 0.0001) and after (r(2) = 0.67, P < 0.0001) CPB. Our findings demonstrated that uncalibrated semi-invasive monitoring system was able to reliably measure CI compared with transpulmonary thermodilution in patients undergoing elective coronary surgery. Furthermore, the semi-invasive monitoring device was able to track haemodynamic changes and trends

Defining the optimal animal model for translational research using gene set enrichment analysis

The mouse is the main model organism used to study the functions of human genes because most biological processes in the mouse are highly conserved in humans. Recent reports that compared identical transcriptomic datasets of human inflammatory diseases with datasets from mouse models using traditional gene‐to‐gene comparison techniques resulted in contradictory conclusions regarding the relevance of animal models for translational research. To reduce susceptibility to biased interpretation, all genes of interest for the biological question under investigation should be considered. Thus, standardized approaches for systematic data analysis are needed. We analyzed the same datasets using gene set enrichment analysis focusing on pathways assigned to inflammatory processes in either humans or mice. The analyses revealed a moderate overlap between all human and mouse datasets, with average positive and negative predictive values of 48 and 57% significant correlations. Subgroups of the septic mouse models (i.e., Staphylococcus aureus injection) correlated very well with most human studies. These findings support the applicability of targeted strategies to identify the optimal animal model and protocol to improve the success of translational research

Context, circuit and modulation of courtship signal selection in Drosophila

Communication is multi-modal -- when we interact, we speak, gesticulate, and touch. However, the neural computations and circuits that select and coordinate these communication signals are unclear. We address this issue in Drosophila melanogaster which, thanks to its complex social behavior and genetic toolbox for manipulating neural activity, is ideal for dissecting the neural basis underlying communication. The courtship ritual, crucial for the survival of the species, is a social behavior which relies on successful communication between male and female flies. The male fly produces a range of signals based on feedback cues from the female to increase his chance of mating. When close to a female, he extends and vibrates one wing to generate air-borne signals, known as the courtship song, but also generates substrate-borne vibrations, providing an additional communication cue to her. Here, we study the specific behavioral context in which vibration signals are chosen over courtship song. On top of that, we propose a central circuit controlling courtship signal selection and test how the circuit's dynamics are modulated by internal state and sensory cues to support context-dependent signaling in social interactions. We developed an experimental setup to record the interactions of courting flies alongside the male song and vibrations. Statistical modeling of the flies' pose properties suggests that males vibrate in response to female immobility. We confirm this hypothesis by optogenetically controlling female walking during courtship. Asking how the selection of courtship signals is centrally controlled, we found two neuron clusters which control vibration and song production with complex dynamics: P1a and pC2l. While optogenetic activation of P1a neurons primarily drives persistent vibrations, pC2l neurons induce song production followed by vibrations. We propose an underlying circuit in which the two clusters drive the output of either signal type while cross inhibiting each other when active. A recurrent network acts presumably on P1a to maintain the persistent vibrations outlasting the neurons activity. This suggests that the two communication modes -- song and vibration -- are not only controlled by a cross-talk between different neuron clusters but also with distinct temporal dynamics, to provide persuasive communication output of the male. Lastly, we show that internal state and sensory cues modify the intrinsic circuit dynamics. Sexually satiated males and naive, highly motivated males differ in their internal state. A lower courtship drive reduces signal output of both clusters P1a and pC2l on intermediate time scales. Sensory cues provided by a receptive female quickly overwrite downstream effects of our circuit motif but also reveal that the mutual inhibition between both outputs is agnostic to social cues. With this, we provide insight into 1) how a social being such as the vinegar fly chooses for a communication signal type depending on its behavioral context and 2) how a neural circuit driving the output of different signal modalities is modulated by internal state and social cues to achieve context-dependent signal selection.2024-02-0

Critical dynamics in spontaneous resting-state oscillations are associated with the attention-related P300 ERP in a go/nogo task

Sustained attention is the ability to continually concentrate on task-relevant information, even in the presence of distraction. Understanding the neural mechanisms underlying this ability is critical for comprehending attentional processes as well as neuropsychiatric disorders characterized by attentional deficits, such as attention deficit hyperactivity disorder (ADHD). In this study, we aimed to investigate how trait-like critical oscillations during rest relate to the P300 evoked potential-a biomarker commonly used to assess attentional deficits. We measured long-range temporal correlations (LRTC) in resting-state EEG oscillations as index for criticality of the signal. In addition, the attentional performance of the subjects was assessed as reaction time variability (RTV) in a continuous performance task following an oddball paradigm. P300 amplitude and latencies were obtained from EEG recordings during this task. We found that, after controlling for individual variability in task performance, LRTC were positively associated with P300 amplitudes but not latencies. In line with previous findings, good performance in the sustained attention task was related to higher P300 amplitudes and earlier peak latencies. Unexpectedly, we observed a positive relationship between LRTC in ongoing oscillations during rest and RTV, indicating that greater criticality in brain oscillations during rest relates to worse task performance. In summary, our results show that resting-state neuronal activity, which operates near a critical state, relates to the generation of higher P300 amplitudes. Brain dynamics close to criticality potentially foster a computationally advantageous state which promotes the ability to generate higher event-related potential (ERP) amplitudes

Dynamic and volumetric variables reliably predict fluid responsiveness in a porcine model with pleural effusion

Background: The ability of stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) for prediction of fluid responsiveness in presence of pleural effusion is unknown. The aim of the present study was to challenge the ability of SVV, PPV and GEDV to predict fluid responsiveness in a porcine model with pleural effusions. Methods: Pigs were studied at baseline and after fluid loading with 8 ml kg−1 6% hydroxyethyl starch. After withdrawal of 8 ml kg−1 blood and induction of pleural effusion up to 50 ml kg−1 on either side, measurements at baseline and after fluid loading were repeated. Cardiac output, stroke volume, central venous pressure (CVP) and pulmonary occlusion pressure (PAOP) were obtained by pulmonary thermodilution, whereas GEDV was determined by transpulmonary thermodilution. SVV and PPV were monitored continuously by pulse contour analysis. Results: Pleural effusion was associated with significant changes in lung compliance, peak airway pressure and stroke volume in both responders and non-responders. At baseline, SVV, PPV and GEDV reliably predicted fluid responsiveness (area under the curve 0.85 (p<0.001), 0.88 (p<0.001), 0.77 (p = 0.007). After induction of pleural effusion the ability of SVV, PPV and GEDV to predict fluid responsiveness was well preserved and also PAOP was predictive. Threshold values for SVV and PPV increased in presence of pleural effusion. Conclusions: In this porcine model, bilateral pleural effusion did not affect the ability of SVV, PPV and GEDV to predict fluid responsiveness

Animal-Ethical Intuitions in Germany: Developing a Measuring Instrument to Capture Domain-Specific Values in the Context of the Human-Animal Relationship

In the recent past, society has increasingly questioned the way animals are treated, especially so-called farm animals. Such ethical values, dealing with the morally correct treatment of animals, affect human behaviour. Therefore, it is of great importance for the agricultural sector in particular to gain a deeper understanding of animal-ethical values in society in order to meet the changing demands. Since such animal-ethical values cover the thematic complex of the human-animal relationship in a very general way and mirror fundamental values, they can be classified in the human value system at the level of domain-specific values. Domain-specific values are characterized by the fact that they are relatively stable over time and are to a certain extent generalizable. The aim of the present study is to develop reliable and valid scales to capture domain-specific values in the context of the human-animal relationship. This is based on core statements of central animal-ethical positions from philosophy. A confirmatory factor analysis reveals that animal-ethical values can be identified in society and that the developed scales are of good reliability and validity. Furthermore, the descriptive results provide a first overview of which animal-ethical values are represented in the German population. Thus, the original anthropocentrism, allowing humans to treat animals as they want, is almost completely rejected. The new contractarian approach (“New Deal”), however, receives an extremely high level of approval. This animal-ethical position in principle allows humans to use animals, but, in exchange, they have to enable them to live a good life

Assessment of the effect of tricaine (MS-222)-induced anesthesia on brain-wide neuronal activity of zebrafish (Danio rerio) larvae

Fast and effective anesthesia is the key for refining many invasive procedures in fish and gaining reliable data. For fish as for all vertebrates, it is also required by European law to reduce pain, suffering, and distress to the unavoidable minimum in husbandry and experiments. The most often used substance to induce anesthesia in zebrafish is tricaine (MS-222). When properly prepared and dosed, tricaine causes rapid loss of mobility, balance and reaction to touch. These signs are interpreted as a stage of deep anesthesia although its effects on the central nervous system have not convincingly been shown. Therefore, it might be possible that tricaine first acts only on the periphery, resulting in a paralyzed instead of an anesthetized fish. This has severe implications for animals undergoing procedures. To investigate the effects of tricaine on the central nervous system, we used zebrafish larvae [Tg( elavl3 :H2B-GCaMP6s)] at 4 days post fertilization (dpf), expressing a calcium indicator (GCaMP6s) in all neurons, that allows monitoring and quantifying the neuronal activity. After treating larvae with 168 mg/L tricaine, a rapid loss of neuronal activity in the forebrain was observed in confocal microscopy. In contrast, only mild effects were seen in the midbrain and hindbrain. In conclusion, the different larval brain areas showed differences in the sensitivity to tricaine treatment. The effects on the central nervous system are indicative of tricaine’s anesthetic function and are consistent with behavioral observations of inactivity and unresponsiveness to touch

Effects of transcutaneous electroacupuncture stimulation (TEAS) on eyeblink, EEG, and heart rate variability (HRV): A non-parametric statistical study investigating the potential of TEAS to modulate physiological markers

This study investigates the effects of transcutaneous electroacupuncture stimulation (TEAS) on eyeblink rate, EEG, and heart rate variability (HRV), emphasising whether eyeblink data-often dismissed as artefacts-can serve as useful physiological markers. Sixty-six participants underwent four TEAS sessions with different stimulation frequencies (2.5, 10, 80, and 160 pps, with 160 pps as a low-amplitude sham). EEG, ECG, PPG, and respiration data were recorded before, during, and after stimulation. Using non-parametric statistical analyses, including Friedman's test, Wilcoxon, Conover-Iman, and bootstrapping, the study found significant changes across eyeblink, EEG, and HRV measures. Eyeblink laterality, particularly at 2.5 and 10 pps, showed strong frequency-specific effects. EEG power asymmetry and spectral centroids were associated with HRV indices, and 2.5 pps stimulation produced the strongest parasympathetic HRV response. Blink rate correlated with increased sympathetic and decreased parasympathetic activity. Baseline HRV measures, such as lower heart rate, predicted participant dropout. Eyeblinks were analysed using BLINKER software (v. 1.1.0), and additional complexity and entropy ('CEPS-BLINKER') metrics were derived. These measures were more predictive of adverse reactions than EEG-derived indices. Overall, TEAS modulates multiple physiological markers in a frequency-specific manner. Eyeblink characteristics, especially laterality, may offer valuable insights into autonomic function and TEAS efficacy in neuromodulation research