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Blood alcohol concentrations above defined levels are detrimental to cognitive performance. Empirical and published evidence suggest that nitrogen narcosis is analogous to alcohol intoxication with both impairing prefrontal cortex function. Nitrogen narcosis is also known to have been a factor in fatal accidents. To examine the effects of nitrogen narcosis, a recent publication used the Iowa Gambling Task tool, to simulate dynamic real-life risky decision-making behaviour. If the reported outcomes are corroborated in larger rigorously designed studies it is likely to provide further evidence that divers may well experience the negative effects of a 'narcotic agent', even at relatively shallow depths. These deleterious effects may occur regardless of diving experience, aptitude or professional status. In 1872, English law made it an offence to be 'drunk' whilst in charge of horses, carriages, cattle and steam engines. Understanding the danger was easy, establishing who is 'drunk' in the eyes of the court required a legal definition. Driving above a 'legal limit' for alcohol was made illegal in the United Kingdom in 1967. The limit was set at 80 milligrams of alcohol per 100 millilitres of blood. It took just short of one hundred years to get from first introducing a restriction to specific activities, whilst under the influence of alcohol, to having a clear and well-defined enforceable law. The question surely is whether our modern society will tolerate another century before legally defining safe parameters for nitrogen narcosis? [ABSTRACT FROM AUTHOR]

From late autumn until the end of winter conditions, bees are exposed to many stress factors including low air temperature and several pathogens. This study aimed to estimate the effects of three commercial materials (acetylsalicylic acid, Echinacea purpurea extract, and vitamin (C) mixed with sugar feeding on some parameters related to stress tolerance using laboratory and field tests. The laboratory tests supported the potential role of vitamin C and Echinacea purpurea extract to enhance the tolerance ability of bees to low temperatures. The most promising results for the recovery time of bees after exposure to low temperatures, survival rates after narcosis, and hemocyte count were recorded with these two materials. After winter the strength of bee colonies fed on sugar feeding mixed with vitamin C and Echinacea purpurea extract were approximately equal to the strength before winter. However, the contrary was obtained with acetylsalicylic acid and the control group. Thus, using vitamin C or Echinacea purpurea extract as safe additives can boost the survival of bee colonies during the winter period. [ABSTRACT FROM AUTHOR]

During deep-sea freediving, many freedivers describe symptoms fairly similar to what has been related to inert gas narcosis in scuba divers. This manuscript aims to present the potential mechanisms underlying these symptoms. First, known mechanisms of narcosis are summarized while scuba diving. Then, potential underlying mechanisms involving the toxicity of gases (nitrogen, carbon dioxide and oxygen) are presented in freedivers. As the symptoms are felt during ascent, nitrogen is likely not the only gas involved. Since freedivers are frequently exposed to hypercapnic hypoxia toward the end of the dive, it is proposed that carbon dioxide and oxygen gases both play a major role. Finally, a new “hemodynamic hypothesis” based on the diving reflex is proposed in freedivers. The underlying mechanisms are undoubtedly multifactorial and therefore require further research and a new descriptive name. We propose a new term for these types of symptoms: freediving transient cognitive impairment. [ABSTRACT FROM AUTHOR]

Purpose: Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. Methods: To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. Results: At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. Conclusions: Divers encounter IGN at – 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives. [ABSTRACT FROM AUTHOR]

Introduction. The present study analyzed the possibility of using neuropsychological tests to assess postoperative cognitive dysfunction. New data were obtained: in the postoperative period, hippocampal memory impairments predominate in patients, which makes it expedient to use methods for diagnosing primary modal-nonspecific memory disorders in patients who are to undergo neurosurgical intervention on the spinal cord.The aim of the study to evaluate the influence of surgery with anesthesia on the cognitive functions of middle-age patients.Materials and methods. The study included 20 middle-aged patients. All patients had to undergo spinal surgery. Patients received total intravenous anesthesia with propofol induction (4–12 mg/kg/hr). Cognitive functions before and after the operation were made with the use of the MoCA, TMT A and B, FCSRT, state-trait anxiety inventory test (STAI).Results. The development of POCD was noted in 15% of cases. The patients showed a decrease in the FCSRT prompt index (1st day = 87 ± 9.0; 2nd day = 83 ± 15; p = 0,0005), while the overall severity of cognitive impairments (total score of MoCA) did not change significantly (standard deviation according to MoCA: 24.25 ± 2.86 on day 1 and 24 ± 3.24 on the second day, p = 0.61). The RT level decreased by day 2: 44.65 ± 7.4 versus 41.1 ± 8.2 (p = 0.001). Correlation analysis did not show the relationship between the age of patients, education level, comorbidity and development of POCD; however, the duration of anesthesia was associated with a decrease in MoCA scores (Pearson’s correlation coefficient r = –0.44; p = 0.050).Conclusion. Thus, our study shows that the study of hippocampal memory impairments is important in patients with POCD. These data differ from the data of researchers presented earlier, where the most important clinical manifestations of POCD are considered to be a decrease in attention and speed of mental processes. Of course, the small sample size dictates the need for additional research.

This article describes the development of decreased intraocular pressure (IOP) under general anesthesia with medetomidine, midazolam, and fentanyl in mice with normal and elevated IOP. IOP was measured using the iCare Tonolab rebound tonometer. Twelve 3–4 months-old male and female C57BL/6J mice were randomized to a control group with physiological IOP and a high IOP group with experimentally induced ocular hypertension using tarsal injections of dexamethasone-21-acetate. For anesthesia, medetomidine and midazolam were used, subgroups additionally received fentanyl. IOP was measured every 2.5 min for 30 min. Control group differed with 14.89 mmHg (SEM: 0.58) significantly (p = 0.0002) from the high IOP group with initial 20.44 mmHg (SEM: 0.75). All groups showed a significant (p < 0.05) decrease in IOP under general anesthesia. There was no significant difference in IOP development and decrease between the group additionally receiving fentanyl and the group without fentanyl. The decrease in IOP was highly dependent on the initial value, with the high IOP group showing a greater decrease. After 10 min, no significant difference in IOP could be detected between the high IOP and control group. In mice, general anesthesia with medetomidine and midazolam leads to a declining IOP over time. Adding fentanyl to the anesthesia did not alter these effects. The decline is time-dependent and IOP-dependent [ABSTRACT FROM AUTHOR]

Blood alcohol concentrations above defined levels are detrimental to cognitive performance. Empirical and published evidence suggest that nitrogen narcosis is analogous to alcohol intoxication with both impairing prefrontal cortex function. Nitrogen narcosis is also known to have been a factor in fatal accidents. To examine the effects of nitrogen narcosis, a recent publication used the Iowa Gambling Task tool, to simulate dynamic real-life risky decision-making behaviour. If the reported outcomes are corroborated in larger rigorously designed studies it is likely to provide further evidence that divers may well experience the negative effects of a 'narcotic agent', even at relatively shallow depths. These deleterious effects may occur regardless of diving experience, aptitude or professional status. In 1872, English law made it an offence to be 'drunk' whilst in charge of horses, carriages, cattle and steam engines. Understanding the danger was easy, establishing who is 'drunk' in the eyes of the court required a legal definition. Driving above a 'legal limit' for alcohol was made illegal in the United Kingdom in 1967. The limit was set at 80 milligrams of alcohol per 100 millilitres of blood. It took just short of one hundred years to get from first introducing a restriction to specific activities, whilst under the influence of alcohol, to having a clear and well-defined enforceable law. The question surely is whether our modern society will tolerate another century before legally defining safe parameters for nitrogen narcosis?, Competing Interests: The authors report no conflicts of interest in this work., (Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.)

Breath-hold diving involves environmental challenges, such as water immersion, hydrostatic pressure, and asphyxia, that put the respiratory system under stress. While training and inherent individual factors may increase tolerance to these challenges, the limits of human respiratory physiology will be reached quickly during deep breath-hold dives. Nonetheless, world records in deep breath-hold diving of more than 214 m of seawater have considerably exceeded predictions from human physiology. Investigations of elite breath-hold divers and their achievements revised our understanding of possible physiological adaptations in humans and revealed techniques such as glossopharyngeal breathing as being essential to achieve extremes in breath-hold diving performance. These techniques allow elite athletes to increase total lung capacity and minimize residual volume, thereby reducing thoracic squeeze. However, the inability of human lungs to collapse early during descent enables respiratory gas exchange to continue at greater depths, forcing nitrogen (N2) out of the alveolar space to dissolve in body tissues. This will increase risk of N2 narcosis and decompression stress. Clinical cases of stroke-like syndromes after single deep breath-hold dives point to possible mechanisms of decompression stress, caused by N2 entering the vasculature upon ascent from these deep dives. Mechanisms of neurological injury and inert gas narcosis during deep breath-hold dives are still incompletely understood. This review addresses possible hypotheses and elucidates factors that may contribute to pathophysiology of deep freediving accidents. Awareness of the unique challenges to pulmonary physiology at depth is paramount to assess medical risks of deep breath-hold diving.

Breath-hold diving involves environmental challenges, such as water immersion, hydrostatic pressure, and asphyxia, that put the respiratory system under stress. While training and inherent individual factors may increase tolerance to these challenges, the limits of human respiratory physiology will be reached quickly during deep breath-hold dives. Nonetheless, world records in deep breath-hold diving of more than 214 m of seawater have considerably exceeded predictions from human physiology. Investigations of elite breath-hold divers and their achievements revised our understanding of possible physiological adaptations in humans and revealed techniques such as glossopharyngeal breathing as being essential to achieve extremes in breath-hold diving performance. These techniques allow elite athletes to increase total lung capacity and minimize residual volume, thereby reducing thoracic squeeze. However, the inability of human lungs to collapse early during descent enables respiratory gas exchange to continue at greater depths, forcing nitrogen (N2) out of the alveolar space to dissolve in body tissues. This will increase risk of N2 narcosis and decompression stress. Clinical cases of stroke-like syndromes after single deep breath-hold dives point to possible mechanisms of decompression stress, caused by N2 entering the vasculature upon ascent from these deep dives. Mechanisms of neurological injury and inert gas narcosis during deep breath-hold dives are still incompletely understood. This review addresses possible hypotheses and elucidates factors that may contribute to pathophysiology of deep freediving accidents. Awareness of the unique challenges to pulmonary physiology at depth is paramount to assess medical risks of deep breath-hold diving. [ABSTRACT FROM AUTHOR]

Research and management programs of wild animal populations often require intensive field actions, which make direct interventions on animals such as capture, immobilization and manipulation, frequently necessary. Such events, however, could induce a stress response causing physiological and behavioural alterations in the individuals. Knowing the impact of these practices in the post-release phase is of crucial importance when studying the spatial behaviour of wild species. Our study aimed to investigate the potential effect of narcosis and application of GPS collars on 17 red deer Cervus elaphus hinds living in a mountainous area in northern Apennine, Italy. We conducted the analysis at a temporal scale of 45 days after release, in order to assess the response of animals in terms of changes in movement rates, distance from the barycentre of their positions and distance from the capture sites. We then compared habitat selection between the period of disturbance and the following days. This work represents the first study of the behavioural responses of wild red deer to capture and handling procedures. We showed that these operations significantly affect the spatial behaviour of hinds by inducing a short-term increase in movement rates and by keeping the animals away from the centre of their activity, for a period no longer than 10 days. The habitat selection analysis remarked a tendency to escape from human disturbance, by avoiding hunting sites and anthropized locations in favour of forest cover. Red deer hinds thus, seem to cope with stressful events and disturbance by adopting a flight behaviour, which includes moving away from the capture area and seeking refuges. The differences highlighted between the 'stressful' period and the following one, showed that such modifications persist for a limited time frame and suggested that this capture method is unlikely to lead to permanent alterations of behaviour. [ABSTRACT FROM AUTHOR]

Paint and varnish removers constitute a major potential source of organic solvent exposure to contractors and home improvement enthusiasts. Unfortunately, the leading paint remover formulations have traditionally contained, as major ingredients, chemicals classified as probable human carcinogens (eg, methylene chloride) or reproductive toxicants (eg, N‐methylpyrrolidone). In addition, because of its unique toxicology (ie, hepatic conversion to carbon monoxide compounding generic solvent narcosis and arrythmogenesis), high volatility, and rigorous requirements for personal protective equipment, methylene chloride exposures from paint removers have been linked to numerous deaths involving both occupational and consumer usage. The aim of this review is to summarize the known toxicology of solvent‐based paint remover constituents (including those found in substitute formulations) in order to provide health risk information to regulators, chemical formulators, and end‐users of this class of products, and to highlight any data gaps that may exist. Solvent‐based paint and varnish removers are an important source of potential consumer and worker exposures. Two historically prominent ingredients, methylene chloride and N‐methylpyrrolidone, have come under increasing scrutiny (and in one case, regulatory action) for their toxicities. This review considers, not only historically prominent paint remover constituents, but also alternative/emerging formulations, and documents important information gaps in their toxicologic testing portfolios. [ABSTRACT FROM AUTHOR]

The physicochemical properties of commercial medical sorbents of carbon dioxide (Amsorb Plus, Dräger 800, Dräger free, Loflosorb, Sodasorb, Sofnolime, Spherasorb, Ventisorb, and Russian XPI absorber) are studied. Their chemical composition, textural characteristics, and duration of protection against CO2 are determined, and the mechanical strength and resistance to abrasion are measured for sorbent granules using the Shell SMS-1471 and ASTM D 4058 96 methods. It is found that the Dräger 800 specimen has the best parameters (high CO2 capacity and strength). The obtained data on the performance of commercial sorbents and the recommendations made in this work can be used in medicine, mine rescue services, and fields of science and industry where the problem of purifying air of carbon dioxide mixtures arises. [ABSTRACT FROM AUTHOR]

Hydrogen phosphide (PH3) is the most commonly used gas for insect control in durable stored products. One of the quick diagnostic tests that are currently in use is the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK), which has been developed by Detia Degesch GmbH (Laudenbach, Germany). DDPTTK provides a rapid evaluation tool for phosphine resistance, where insects are exposed in syringes that contain a high concentration of gas (e.g. 3000 ppm), while this gas is produced on site by adding tablets into a canister. We used DDPTTK to evaluate resistance of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to phosphine. For this purpose, we followed a specific succession of observations on the exposed adults of this species, in an effort to set the scene for designing a rapid diagnostic tool for phosphine resistance, based upon quick bioassays. Two T. castaneum strains were used, one susceptible and one resistant to phosphine. Twenty adults of each of the populations (separate sets of adults each time) were placed in syringe of 100 ml under 1000 or 3000 ppm of phosphine. The insects inside the syringe were monitored at 15-min intervals, for a total period of 90 min, and classified as active, under narcosis and immobilized. After this period, all insects were removed from the syringe and placed in plastic petri dishes with a small quantity of wheat flour. The insects were classified again at the three categories above, after 2 h, 1 d, 2 d, 3 d and 7 d. Regarding the exposure period, at 1000 ppm, all adults of the susceptible strain were immobilized after 60 min of exposure, and remained at this condition until the end of the observation period. At the same concentration, the majority of adults of the resistant strain remained active until the end of the observation period. At 3000 ppm, for the susceptible strain, all adults became immobilized after 90 min observation. For the same concentration, the percentage of the adults of the resistant strain that were active was notably reduced in comparison with 1000 ppm. For the post-exposure period, at 1000 or 3000 ppm, for the susceptible strain, the number of adults that were immobilized reached 95 % after 7 d. At the same phosphine concentration, almost all of the adults of the resistant strain were active even at the 2 h post-exposure period, and practically remain at this condition until the end of the observation period. Our findings indicate that time-to-narcosis / immobilization is inversely proportional to time-to-recovery of the same individuals, and this characteristic can be also considered as an indicator for resistance.

Identifying chemicals with narcotic potency is an important aspect of assessing the safety of consumer products that may be accidentally ingested. A rapid and efficient assay of narcotic potency is desired for assessing chemicals with such suspected activity. This purpose of this research was to develop a non-mammalian vertebrate, high throughput, neurobehavioral method to assess the narcotic potency of chemicals using larval zebrafish. Larval zebrafish were acutely exposed to chemicals beginning at 5 days post fertilization (5 dpf). Locomotor activity, elicited by regular, periodic photostimulation, was quantified using a video tracking apparatus. Narcotic potency was determined as the molar concentration at which photostimulated locomotor activity was reduced by 50% (IC 50). Toxicity was assessed based on observations of morbidity or mortality. Recovery was assessed following removal of test material by serial dilution and reassessment of photostimulated behavior 24 hr later (6 dpf). A total of 21 chemicals were assessed. Etomidate, a human narcotic analgesic agent, was used as a reference material. Investigating a series of eleven linear, primary alcohols (C6 to C16), a relationship between narcotic potency and carbon number was observed; narcotic potency increased with carbon number up to C12, consistent with historical studies. For a set of technical grade surfactants, nonionic surfactants (i.e., alcohol ethoxylates) were observed to be narcotic agents while anionic surfactants produced evidence of reduced locomotor activity only in combination with toxicity. Of the solvents evaluated, only ethanol exhibited narcotic activity with an IC 50 of 261 mM and was the least potent of the chemicals investigated. Etomidate was the most potent material evaluated with an IC 50 of 0.39 μM. Conclusions: The larval zebrafish neurobehavioral assay provides a method capable of estimating the narcotic potency of chemicals and can identify if toxicity contributes to observed neurobehavioral effects in the test organism. [ABSTRACT FROM AUTHOR]

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Introduction: Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen (O2) fractions was investigated. Methods: Eight male volunteers performed, in random order, two dry chamber dives breathing either air or EANx40 (40% O2-60% nitrogen) for 20 minutes (min) at 0.4 MPa. Cognition and arousal were assessed before the dive; upon arrival at 0.4 MPa; after 15 min exposure at 0.4 MPa; on surfacing and 30 min post-dive using behavioural computer-based testing psychology experiment building language (PEBL) and by CFFF while continuously recording brain oxygenation with near-infrared spectroscopy. Results: In both breathing conditions, CFFF and PEBL demonstrated a significant inverse correlation (Pearson r of -0.90, P < 0.0001), improved cognitive abilities/cerebral arousal occurred upon arrival at 0.4 MPa followed by a progressive deterioration. Initial brain activation was associated with a significant increase in oxyhaemoglobin (HbO2) and a simultaneous decrease of deoxyhaemoglobin (HHb). The magnitude of the changes was significantly greater under EANx (P = 0.038). Conclusions: Since changes were not related to haemodynamic variables, HbO2 and HHb values indicate a significant, O2-dependent activation in the prefrontal cortex. Owing to the correlation with some tests from the PEBL, CFFF could be a convenient measure of cognitive performance/ability in extreme environments, likely under the direct influence of oxygen partial pressure, a potent modulator of IGN symptoms. [ABSTRACT FROM AUTHOR]

Research and management programs of wild animal populations often require intensive field actions, which make direct interventions on animals such as capture, immobilization and manipulation, frequently necessary. Such events, however, could induce a stress response causing physiological and behavioural alterations in the individuals. Knowing the impact of these practices in the post-release phase is of crucial importance when studying the spatial behaviour of wild species. Our study aimed to investigate the potential effect of narcosis and application of GPS collars on 17 red deer Cervus elaphus hinds living in a mountainous area in northern Apennine, Italy. We conducted the analysis at a temporal scale of 45 days after release, in order to assess the response of animals in terms of changes in movement rates, distance from the barycentre of their positions and distance from the capture sites. We then compared habitat selection between the period of disturbance and the following days. This work represents the first study of the behavioural responses of wild red deer to capture and handling procedures. We showed that these operations significantly affect the spatial behaviour of hinds by inducing a short-term increase in movement rates and by keeping the animals away from the centre of their activity, for a period no longer than 10 days. The habitat selection analysis remarked a tendency to escape from human disturbance, by avoiding hunting sites and anthropized locations in favour of forest cover. Red deer hinds thus, seem to cope with stressful events and disturbance by adopting a flight behaviour, which includes moving away from the capture area and seeking refuges. The differences highlighted between the 'stressful' period and the following one, showed that such modifications persist for a limited time frame and suggested that this capture method is unlikely to lead to permanent alterations of behaviour. [ABSTRACT FROM AUTHOR]

Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO2 or electricity. Exposure to water saturated with CO2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO2 did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO2. This result is surprising considering that the behavioural reactions were much more pronounced following CO2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.

Two mononuclear Pd(II) complexes [PdCl2(pfptp)] (1) and [PdCl2(pfhtp)] (2), with ligands 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), were synthesized and structurally characterized. The two complexes showed a bidentate coordination of the ligand occurring through N atom of pyridine ring and N4 atom of 1,2,4-triazole. Both complexes showed antimicrobial activity when tested against both Gram-negative and Gram-positive bacterial strains.

Objective of the study was to compare two commonly used anesthetic drugs, S-ketamine and etomidate, regarding their influence on seizure characteristics, safety aspects, and outcome of electroconvulsive therapy (ECT) in major depression. Treatment data of 60 patients who underwent a total number of 13 ECTs (median) because of the severe or treatment-resistant major depressive disorder (DSM-IV) were analyzed. Etomidate, mean dosage (SD) = 0.25 (0.04) mg/kg, was used for anesthesia in 29 participants; 31 patients received S-ketamine, mean dosage (SD) = 0.96 (0.26) mg/kg. Right unilateral brief pulse ECTs were performed. The number of ECTs was individually adjusted to clinical needs, mean (SD) = 13.0 (4.3). Seizure characteristics, adverse events, and the clinical global impression (CGI) scores were compared between the both groups during ECT series. In the S-ketamine group, a lower initial seizure threshold ( p = 0.014), stimulation charge ( p < 0.001), higher postictal suppression ( p < 0.001), EEG ictal amplitude ( p = 0.04), EEG coherence ( p < 0.001) and maximum heart rate ( p = 0.015) were measured. Etomidate was associated with more frequent abortive seizures ( p = 0.02) and restimulations ( p = 0.01). The CGI scores, the number of sessions within an ECT series, and the incidence of adverse events did not differ between groups. Due to its lower initial seizure threshold, S-ketamine might hold a potential to become a clinically favorable anesthetic agent during ECT. However, the current findings should be interpreted with caution, and further prospective randomized clinical trials are required. Also, specific adverse effects profile of S-ketamine, especially with regard to the cardiovascular risk, needs to be taken into account. [ABSTRACT FROM AUTHOR]

Inability to secure the airway of a patient after induction of anaesthesia may lead to serious consequences including permanent brain damage and even death. Hypoxia is quite common in difficult intubations especially when it is difficult to ventilate the patient. However, carbon dioxide retention severe enough to cause carbon dioxide narcosis and delayed recovery is a rare occurrence. Here, we report a case of a craniovertebral junction anomaly where inadequate ventilation after induction of anaesthesia resulted in carbon dioxide narcosis and delayed awakening. A 54-year-old, American Society of Anesthesiologists II female patient weighing 70 kg with a diagnosis of craniovertebral junction was scheduled for implant removal for dislodged occipital screw. Fibreoptic intubation was attempted after induction of anaesthesia and muscle paralysis. Even after multiple attempts, intubation could not be done and ventilation by face mask became difficult. Though oxygen saturation could be maintained with the insertion of a laryngeal mask airway (LMA), ventilation was not adequate. The patient remained unresponsive long after discontinuation of anaesthetic agent and reversal of muscle paralysis. Subsequent blood gas analysis showed severe carbon dioxide retention and respiratory acidosis. Patient was given assist control mechanical ventilation through LMA. LMA was removed after improvement in sensorium and the blood gas picture.

Resistance to the fumigant phosphine in Tribolium castaneum occurs worldwide. This study evaluated tests based on adult knockdown time, the time for a beetle to become immobile, when exposed to a high concentration of phosphine. We recorded knockdown times of beetles that remained completely still for 30 s when exposed to 3000 ppm of phosphine in a large, gas-tight glass tube. Beetles were used from 12 populations, of which six were ‘susceptible’ to phosphine, three were ‘weakly resistant’, and three were ‘strongly resistant’. Knockdown times were determined for single beetles, as well as for groups of ten beetles for which the time to knockdown for either five beetles (KT50) or ten beetles (KT100) were recorded. Similar knockdown times occurred across susceptible and resistant populations. However, the KT100 tests generated conservative times for diagnosing strong vs. weak resistance. The strong resistant populations were all over 100 min with KT100, compared to 60 min or less for susceptible and weak resistant populations. Special tests on single beetles revealed higher knockdown times in insects that were deliberately disturbed compared to those without any disturbances. Work reported here suggests a knockdown test conducted on beetles in a matter of minutes or hours could help classify phosphine resistance status prior to decisions on phosphine fumigation.

BACKGROUND: The few prior studies of time perception underwater have reached contradictory conclusions as to how, and if, time perception becomes distorted when submerged. The current paper expands upon this limited data by describing two studies of prospective time production in scuba divers. METHODS: Study 1 (N = 32) compared performance on a 30-s interval time production task in deep water (35 m-42 m/~115-138 ft) with a shallow water control (3-12 m/~10-39 ft). Using the same task, study 2 (N = 31) tested performance at the surface and at a range of depths underwater (1 m/3 ft; 11 m/36 ft; 20 m/66 ft; 30 m/98 ft; 40 m/131 ft). RESULTS: Study 1 revealed time production to be significantly longer in deep water compared to shallow water. In study 2 time production at the surface was not significantly different from that at 1 m, but productions at 11-40 m were significantly longer than at both 1 m and on the surface. Time productions between 11-40 m did not differ significantly. DISCUSSION: It was concluded that divers judge less time to have passed underwater than is objectively the case from a depth of 11 m, but that this effect does not deteriorate significantly once past 11 m. The cause of this distortion of time perception underwater was suggested to be the action of gas narcosis. [ABSTRACT FROM AUTHOR]

This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria ( Vibrio fischeri), microalgae ( Pseudokirchneriella subcapitata), and freshwater crustaceans ( Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed. [ABSTRACT FROM AUTHOR]

The Alberta oil sands are one of the largest global petroleum deposits and, due to non-release practices for oil sands process-affected waters, produced tailings are stored in large ponds. The acid extractable organic (AEO) compounds in oil sands process-affected water are of greatest concern due to their persistence and toxicity to a variety of aquatic biota. The present study evaluated the toxicity of the five AEO fractions to two fish species: Oryzias latipes (Japanese medaka) and Pimephales promelas (fathead minnow). The fractions (F1-F5) were comprised of AEO with increasing mean molecular weight and subsequent increases in cyclicity, aromaticity, degree of oxygenation, and heteroatom content. The lowest molecular weight fraction, F1, displayed the lowest acute toxicity to both fish species. For fathead minnow, F5 displayed the greatest toxic potency, while F2 to F4 displayed intermediate toxicities. For Japanese medaka, F2 and F3 displayed the greatest acute toxicities and F1, F4 and F5 were significantly less potent. Overall, fathead minnow were more acutely sensitive to AEO than Japanese medaka. The present study indicates that AEO toxicity may not be solely driven by a narcotic mode of action, but chemical composition such as aromaticity and heteroatom content and their relation to toxicity suggest other drivers indicative of additional modes of toxic action. [ABSTRACT FROM AUTHOR]

Interpretation and use of data from high-throughput assays for chemical toxicity require links between effects at molecular targets and adverse outcomes in whole animals. The well-characterized genome of Drosophila melanogaster provides a potential model system by which phenotypic responses to chemicals can be mapped to genes associated with those responses, which may in turn suggest adverse outcome pathways associated with those genes. To determine the utility of this approach, we used the Drosophila Genetics Reference Panel (DGRP), a collection of ~200 homozygous lines of fruit flies whose genomes have been sequenced. We quantified toluene-induced suppression of motor activity in 123 lines of these flies during exposure to toluene, a volatile organic compound known to induce narcosis in mammals via its effects on neuronal ion channels. We then applied genome-wide association analyses on this effect of toluene using the DGRP web portal (http://dgrp2.gnets.ncsu.edu), which identified polymorphisms in candidate genes associated with the variation in response to toluene exposure. We tested ~2 million variants and found 82 polymorphisms located in or near 66 candidate genes that were associated with phenotypic variation for sensitivity to toluene at P<5 × 10-5, and human orthologs for 52 of these candidate Drosophila genes. None of these orthologs are known to be involved in canonical pathways for mammalian neuronal ion channels, including GABA, glutamate, dopamine, glycine, serotonin, and voltage sensitive calcium channels. Thus this analysis did not reveal a genetic signature consistent with processes previously shown to be involved in toluene-induced narcosis in mammals. The list of the human orthologs included Gene Ontology terms associated with signaling, nervous system development and embryonic morphogenesis; these orthologs may provide insight into potential new pathways that could mediate the narcotic effects of toluene. [ABSTRACT FROM AUTHOR]

Purpose. The implementation of interventions to mitigate the causes of opioid-induced oversedation and respiratory depression (OSRD) is reported. Summary. A single-site retrospective review of eligible rescue naloxone cases was conducted to identify the causes of opioid-induced OSRD in a hospital as well as to identify risk factors. A survey was used to assess potential opioid knowledge deficits among hospitalist prescribers. Based on the findings of the case reviews and results of the opioid knowledge assessments, a series of interventions to address noted deficiencies was implemented over the ensuing months, including enhanced monitoring for sedation, improved clinical decision support in the electronic medical record (EMR), and various adjustments to dosing for high-risk patients. The primary endpoint of our analysis was naloxone use for documented cases of opioid-induced OSRD to determine the effectiveness of the interventions. A mean of 16 OSRD events occurred per quarter before intervention implementation. An average of five risk factors (range, two to six) was found among OSRD cases, most commonly age of >60, obesity, and comorbidities of the kidneys and lungs. Deficiencies of clinical care were found in four inter-related domains: knowledge deficits, inadequate monitoring, failure to leverage the EMR, and cultural issues regarding pain assessments and sedation management. Conclusion. Implementation of solution bundles that utilized an EMR to create meaningful clinical decision support and cultural changes related to pain goals and communication about sedation level at an acute care hospital resulted in a fivefold reduction in OSRD events that has been sustained for two years. [ABSTRACT FROM AUTHOR]

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The article presents a case study of a 41‐year‐old man referred for catheter ablation (CA) due to drug‐resistant atrial fibrillation (AF). It mentions his performance of the transseptal approach, direct current (DC) cardioversion for the restoration of sinus rhythm and also mentions the subsequent clinical manifestations of carbon dioxide narcosis (CDN).

We here describe a method for permanently mounting specimens on microscope slides, as we applied it in the newly established rotifer collection in Ulaanbaatar, Mongolia. The liquid photopolymer NOA 61 was used as a primary sealant for pure glycerine mounts. We furthermore outline simple methods of rotifer narcotization and fi xation in the fi eld that yield, for the majority of species, adequately preserved specimen material for further preparation and identifi cation purposes.

Diving narcosis results from the complex interaction of gases, activities, and environmental conditions. We hypothesized that these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO2, N2, and O2 in immersed, exercising subjects while assessing multitasking performance with the Multi-Attribute Task Battery II (MATB-II) flight simulator. Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting U.S. Navy age and fitness profiles. Inspired nitrogen (N2) and oxygen (O2) partial pressures were 0, 4.5, and 5.6 ATA and 0.21, 1.0, and 1.22 ATA, respectively, at rest and during 100-W immersed exercise with and without 0.075-ATA CO2. Linear regression modeled the association of gas partial pressure with task performance while controlling for exercise, hypercapnic ventilatory response, dive training, video game frequency, and age. Subjects served as their own controls. Impairment of memory, attention, and planning, but not motor tasks, was associated with N2 partial pressures >4.5 ATA. Sea level O2 at 0.925 ATA partially rescued motor and memory reaction time impaired by 0.075-ATA CO2; however, at hyperbaric pressures an unexpectedly strong interaction between CO2, N2, and exercise caused incapacitating narcosis with amnesia, which was augmented by O2. Perception of narcosis was not correlated with actual scores. The relative contributions of factors associated with diving narcosis will be useful to predict the effects of gas mixtures and exercise conditions on the cognitive performance of divers. The O2 effects are consistent with O2 narcosis or enhanced O2 toxicity. [ABSTRACT FROM AUTHOR]

Introduction: Inert gas narcosis (IGN) impairs cognitive performance and some divers are more susceptible to IGN than others. We compared the sensitivity of two reaction time tests to detect changes in performance at pressure and compared these results with critical flicker fusion frequency (CFF) changes at the same ambient pressures. Methods: The study assessed simple reaction time (RT), mean time correct of the discrimination reaction time (MTC) and CFF in 30 professional divers breathing air at 101 kPa and 608 kPa in a hyperbaric chamber. Results: RT and MTC increased at 608 kPa by 5.1 ± 9.4% (P = 0.04) and 7.3 ± 12.3% (P = 0.01) respectively. RT decreased to pre-compression level after decompression and MTC decreased to a level lower than pre-compression (P < 0.001) values. CFF increased by 2.5 ± 2.8% (P < 0.001) at 608 kPa. CFF decreased to pre-compression level after decompression. An increase in CFF was inversely correlated with a decrease in RT (r = 0.38, P = 0.04) and in MTC (r = 0.43, P = 0.02) at 608 kPa. Conclusions: Response speeds of the same subjects were impaired in both reaction time tasks at 608 kPa, whereas CFF increased at depth. An association between changes in response times and changes in CFF suggests that divers susceptible to IGN may also be susceptible to the effects of elevated oxygen partial pressure. If this holds true, the future selection of professional divers could be improved by the use of simple cognitive tests. [ABSTRACT FROM AUTHOR]

Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO 2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO 2 or electricity. Exposure to water saturated with CO 2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO 2 did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO 2. This result is surprising considering that the behavioural reactions were much more pronounced following CO 2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture. [ABSTRACT FROM AUTHOR]

The article presents the data on comparative analysis of two medical cases of myasthenia patients, analysis of general anesthetization and post-surgical process. The influence of previous therapy, overall condition and accompanied pathology is stated

The nematode Caenorhabditis elegans has been widely used as a model organism for assessing chemical toxicity. So far, however, a respective baseline narcosis reference has been lacking to predict narcosis-level toxicity and to identify excess-toxic compounds and associated mechanisms of action. Employing 22 organic narcotics that cover 7.2 units of their log K (octanol/water partition coefficient) from -1.20 to 6.03, a baseline narcosis model has been derived for a glass-vial 96-h growth inhibition test with ow (octanol/water partition coefficient) from -1.20 to 6.03, a baseline narcosis model has been derived for a glass-vial 96-h growth inhibition test with C. elegans , both without and with correction for compound loss through volatilization and sorption. The resultant effective concentrations yielding 50% growth inhibition, EC 50 , vary by 6.4 log units from 5.04 · 10 -1 to 1.90 · 10 -7 ) of four Michael-acceptor carbonyls driven by their reactive mode of action. Moreover, narcosis-level predicted vs experimental EC T e ) of four Michael-acceptor carbonyls driven by their reactive mode of action. Moreover, narcosis-level predicted vs experimental EC 50 regarding ADH (alcohol dehydrogenase). The discussion includes narcosis-level and excess-toxicity doses (critical body burdens) as well as chemical activities α,β -unsaturated alcohols demonstrate the biotransformation capability of C. elegans regarding ADH (alcohol dehydrogenase). The discussion includes narcosis-level and excess-toxicity doses (critical body burdens) as well as chemical activities A baseline narcosis enables generating respective pre-test expectations, enriches experimental results by mechanistic information, and may complement 3Rs (reduce, refine, replace) test batteries through its ADH metabolic capacity.50 (at the EC 50 ) as compared to fish, daphnids, ciliates, bacteria, zebrafish embryo, and cell lines. Overall, the presently introduced model for predicting C. elegans baseline narcosis enables generating respective pre-test expectations, enriches experimental results by mechanistic information, and may complement 3Rs (reduce, refine, replace) test batteries through its ADH metabolic capacity.

Carbon dioxide and cold narcosis have been found to have various effects on insect behaviour and physiology, ranging from changes in fecundity and memory to alterations in aggression and foraging. In spite of these potentially confounding effects, narcosis is repeatedly used to handle insects prior to experimental studies. To begin disentangling the unintended effects of narcosis from the effects of experimental manipulation, a better understanding is needed of how different types of narcosis affect insect behaviour, as well as the time frames of these effects. Here, we compare the effects of CO and cold narcosis relative to control animals regarding activity, foraging, brood care, aggression, and productivity of worker bumblebees, Bombus terrestris. We show that even a single narcosis event with either cold or CO affects these behaviours often in dissimilar ways, and these effects are maintained for at least 4 days following narcosis. [ABSTRACT FROM AUTHOR]

The data generated by current high-throughput assays for chemical toxicity require information to link effects at molecular targets to adverse outcomes in whole animals. In addition, more efficient methods for testing volatile chemicals are needed. Here we begin to address these issues by determining the utility of measuring behavioral responses of Drosophila melanogaster to airborne volatile organic compounds (VOCs) as a potential model system for discovering adverse outcome pathways and as a method to test for toxicity. In these experiments, we measured motor activity in male and female flies to determine concentration–effect functions for three VOCs that differ in their mode of action: toluene, a narcotic; acrolein, an irritant; and vinyl chloride, a hepatocarcinogen. These experiments were conducted in Flyland, an outbred population of flies derived from 40 lines of the Drosophila Genetics Reference Panel (DGRP) (Mackay et al., 2012), in preparation for subsequent experiments with individual lines of the DGRP. Systematic, concentration-related changes in activity were observed with toluene, but not with acrolein; high concentrations of vinyl chloride reduced activity by a small amount. Despite higher activity levels in males than in females under control conditions, the sexes were equally sensitive to toluene. Transient increases in activity at the onset and offset of exposure to toluene and vinyl chloride suggested that the flies detected changes in air quality at concentrations that did not persistently suppress activity. The effects and potency of toluene are consistent with those observed in rodents. The lack of clear concentration-related changes in response to acrolein and vinyl chloride shows limitations of this method is for screening toxicity attributed to VOCs. This abstract does not reflect U.S. EPA policy . [ABSTRACT FROM AUTHOR]

It has been postulated that a number of the central effects of ethanol are mediated via ethanol metabolites: acetaldehyde and acetate. Ethanol is known to produce a large variety of behavioral actions such anxiolysis, narcosis and modulation of locomotion. Acetaldehyde contributes to some of those effects although the contribution of acetate is less known. In the present studies rats and mice were used to assess the acute and chronic effects of acetate after central or peripheral administration. Male Sprague-Dawley rats were used for the comparison between central (intraventricular, ICV) and peripheral (intraperitoneal, IP) administration of acute doses of acetate on locomotion. CD1 male mice were used to study acute IP effects of acetate on locomotion, and also the effects of chronic oral consumption of acetate (0, 500 or 1000 mg/l, during 7, 15, 30 or 60 days) on ethanol- (1.0, 2.0, 4.0 or 4.5 g/kg, IP) induced locomotion, anxiolysis and loss of righting reflex (LORR). In rats, ICV acetate (0.7-2.8 μmoles) reduced spontaneous locomotion at doses that, in the case of ethanol and acetaldehyde, had previously been shown to stimulate locomotion. Peripheral acute administration of acetate also suppressed locomotion in rats (25-100 mg/kg), but not in mice. In addition, although chronic administration of acetate during 15 days did not have an effect on spontaneous locomotion in an open field, it blocked ethanol-induced locomotion. However, ethanol-induced anxiolysis was not affected by chronic administration of acetate. Chronic consumption of acetate (up to 60 days) did not have an effect on latency to, or duration of LORR induced by ethanol, but significantly increased the number of mice that did not achieve LORR. The present work provides new evidence supporting the hypothesis that acetate should be considered a centrally-active metabolite of ethanol that contributes to some behavioral effects of this alcohol, such as motor suppression.