Repeated, High-dose Fentanyl Administration in Rats Reveals Minimal Tolerance to Unconsciousness, Bradycardia, Muscle Rigidity and Respiratory Depression.

Background: Fentanyl is a synthetic opioid that is widely used in anesthesiology, but its illicit use is rapidly increasing. At high doses fentanyl induces unconsciousness and muscle rigidity, the mechanisms of which are poorly understood. Since animal models are needed to study these effects, the aim of this study was to establish a rat model of fentanyl abuse and investigate the effects of repeated high-dose fentanyl injections on loss of righting reflex, heart rate, respiratory depression, muscle, and brain activity.

Electrical stimulation of the ventral tegmental area restores consciousness from sevoflurane-, dexmedetomidine-, and fentanyl-induced unconsciousness in rats.

Background: Dopaminergic neurons in the ventral tegmental area (VTA) are crucially involved in regulating arousal, making them a potential target for reversing general anesthesia. Electrical deep brain stimulation (DBS) of the VTA restores consciousness in animals anesthetized with drugs that primarily enhance GABA receptors. However, it is unknown if VTA DBS restores consciousness in animals anesthetized with drugs that target other receptors.

Substance specific EEG patterns in mice undergoing slow anesthesia induction.

The exact mechanisms and the neural circuits involved in anesthesia induced unconsciousness are still not fully understood. To elucidate them valid animal models are necessary. Since the most commonly used species in neuroscience are mice, we established a murine model for commonly used anesthetics/sedatives and evaluated the epidural electroencephalographic (EEG) patterns during slow anesthesia induction and emergence.

Electroencephalographic guided propofol-remifentanil TCI anesthesia with and without dexmedetomidine in a geriatric population: electroencephalographic signatures and clinical evaluation.

Elderly and multimorbid patients are at high risk for developing unfavorable postoperative neurocognitive outcomes; however, well-adjusted and EEG-guided anesthesia may help titrate anesthesia and improve postoperative outcomes. Over the last decade, dexmedetomidine has been increasingly used as an adjunct in the perioperative setting. Its synergistic effect with propofol decreases the dose of propofol needed to induce and maintain general anesthesia.

Permutation entropy is not an age-independent parameter for EEG-based anesthesia monitoring.

Background: An optimized anesthesia monitoring using electroencephalographic (EEG) information in the elderly could help to reduce the incidence of postoperative complications. Processed EEG information that is available to the anesthesiologist is affected by the age-induced changes of the raw EEG. While most of these methods indicate a "more awake" patient with age, the permutation entropy (PeEn) has been proposed as an age-independent measure.

Performance of the SEDLine Monitor: Age Dependency and Time Delay.

Background: Devices monitoring the hypnotic component of general anesthesia can help to guide anesthetic management. The main purposes of these devices are the titration of anesthesia dose. While anesthesia at low doses can result in awareness with intraoperative memory formation, excessive administration of anesthetics may be associated with an increased risk of postoperative neurocognitive disorder.

Connected consciousness after tracheal intubation in young adults: an international multicentre cohort study.

Background: Connected consciousness, assessed by response to command, occurs in at least 5% of general anaesthetic procedures and perhaps more often in young people. Our primary objective was to establish the incidence of connected consciousness after tracheal intubation in young people aged 18-40 yr. The secondary objectives were to assess the nature of these responses, identify relevant risk factors, and determine their relationship to postoperative outcomes.

Combined implanted central venous access and cortical recording electrode array in freely behaving mice.

Establishing a long-lasting, functioning venous access in a non-anesthetized mouse is very challenging at least. Since we needed a reliable venous access to titrate intravenous anesthetics, we refined and combined previously described methods. The tunneling of the catheter from the cranial to the pectoral wound, the fixation of the catheter in the external jugular vein with two sutures, and a tissue adhesive allowed us to combine this method with the implantation of intracranial recording electrodes.

The First Derivative of the Electroencephalogram Facilitates Tracking of Electroencephalographic Alpha Band Activity During General Anesthesia.

Background: Intraoperative neuromonitoring can help to navigate anesthesia. Pronounced alpha oscillations in the frontal electroencephalogram (EEG) appear to predict favorable perioperative neurocognitive outcomes and may also provide a measure of intraoperative antinociception. Monitoring the presence and strength of these alpha oscillations can be challenging, especially in elderly patients, because the EEG in these patients may be dominated by oscillations in other frequencies.

Implicit Memory and Anesthesia: A Systematic Review and Meta-Analysis.

General anesthesia should induce unconsciousness and provide amnesia. Amnesia refers to the absence of explicit and implicit memories. Unlike explicit memory, implicit memory is not consciously recalled, and it can affect behavior/performance at a later time.

The influence of age on EEG-based anaesthesia indices.

Study Objective: In the upcoming years there will be a growing number of elderly patients requiring general anaesthesia. As age is an independent risk factor for postoperative delirium (POD) the incidence of POD will increase concordantly. One approach to reduce the risk of POD would be to avoid excessively high doses of anaesthetics by using neuromonitoring to guide anaesthesia titration.

ER stress preconditioning ameliorates liver damage after hemorrhagic shock and reperfusion.

The mismatch of oxygen supply and demand during hemorrhagic shock disturbs endoplasmic reticulum (ER) homeostasis. The resulting accumulation of unfolded proteins in the ER lumen, which is a condition that is defined as ER stress, triggers the unfolded protein response (UPR). Since the UPR influences the extent of organ damage following hemorrhagic shock/reperfusion (HS/R) and mediates the protective effects of stress preconditioning before ischemia-reperfusion injury, the current study investigated the mechanisms of ER stress preconditioning and its impact on post-hemorrhagic liver damage.

Age-Related EEG Features of Bursting Activity During Anesthetic-Induced Burst Suppression.

Electroencephalographic (EEG) Burst Suppression (BSUPP) is a discontinuous pattern characterized by episodes of low voltage disrupted by bursts of cortical synaptic activity. It can occur while delivering high-dose anesthesia. Current research suggests an association between BSUPP and the occurrence of postoperative delirium in the post-anesthesia care unit (PACU) and beyond.

Gelatin coating increases in vivo bone formation capacity of three-dimensional 45S5 bioactive glass-based crystalline scaffolds.

Recent studies have demonstrated that surface characteristics, porosity, and mechanical strength of three-dimensional 45S5-type bioactive glass (BG)-based scaffolds are directly correlated with osteogenic properties. Three-dimensional BG-based scaffolds obtained from maritime natural sponges (MNSs) as sacrificial templates exhibit the required morphological properties; however, no in vivo data about the osteogenic features are available. In this study, uncoated (Group A) and gelatin-coated (Group B) crystalline MNS-obtained BG-based scaffolds were evaluated mechanically and seeded with human mesenchymal stem cells prior to subcutaneous implantation in immunodeficient mice.

Modulation of Endoplasmic Reticulum Stress Influences Ischemia-Reperfusion Injury After Hemorrhagic Shock.

Background: Impaired function of the endoplasmic reticulum (ER) results in ER stress, an accumulation of proteins in the ER lumen. ER stress is a major contributor to inflammatory diseases and is part of the pathomechanism of ischemia-reperfusion injury (IRI). Since severe traumatic injury is often accompanied by remote organ damage and immune cell dysfunction, we investigated the influence of ER stress modulation on the systemic inflammatory response and liver damage after hemorrhagic shock and reperfusion (HS/R).

Hepatic topographical changes of endoplasmic reticulum stress and unfolded protein response signaling after hemorrhagic shock and reperfusion.

Background: Endoplasmic reticulum (ER) stress plays a crucial role in cell death decisions in context of various diseases. Although it is known that ER stress occurs in livers subjected to hemorrhagic shock and reperfusion (HS/R), there is no understanding about the influence of the liver architecture on ER stress and the activation of the unfolded protein response (UPR).

Materials And Methods: Mice were subjected to a pressure-controlled HS (30 ± 5 mmHg) for 90 min.

Environmental tobacco smoke furthers progression of diabetic nephropathy.

Clinical studies suggest that smoking is a risk factor in the progression of chronic kidney disease, including diabetic nephropathy. The mechanisms involved are not completely understood. We have previously demonstrated that nicotine, one of the compounds present in large amounts in tobacco, promotes mesangial cell proliferation and fibronectin production.