Identification of neurotoxicology (NT)/developmental neurotoxicology (DNT) adverse outcome pathways and key event linkages with in vitro DNT screening assays.

There is a need to assess compounds reliably and quickly for neurotoxicity (NT) and developmental neurotoxicity (DNT). Adverse outcome pathways (AOPs) enable the mapping of molecular events to an apical endpoint in a chemical agnostic manner and have begun to be applied in NT and DNT testing frameworks. We assessed the status of NT/DNT AOPs in the AOP-Wiki (ca. 2/1/23; https://aopwiki.org/), to characterize the state of AOP development, identify strengths and knowledge gaps, elucidate areas for improvement, and describe areas for future focus. AOPs in the Wiki database were assessed for inclusion of NT/DNT molecular events and endpoints, AOP development and endorsement, as well as the linkages of key neurodevelopmental processes with in vitro new approach methods (NAMs). This review found that 41 AOPs have been proposed detailing NT/DNT, of which eight were endorsed by working parties in OECD. Further, this review determined that learning and memory is included as an adverse outcome in eight NT/DNT AOPS, often without distinction regarding the varying forms of learning and memory, regional specification, temporal dynamics, or acquisition mechanisms involved. There is also an overlap with key events (KEs) and in vitro NAMs, which synaptogenesis appeared as a common process. Overall, progress on NT/DNT AOPs could be expanded, adding in modes of action that are missing, improvement in defining apical endpoints, as well as utilizing NAMs further to develop AOPs and identify gaps in current knowledge.

Proteome Profiling of Rat Brain Cortical Changes during Early Postnatal Brain Development.

Label-free quantitation (LFQ) was applied to proteome profiling of rat brain cortical development during the early postnatal period. Male and female rat brain extracts were prepared using a convenient, detergent-free sample preparation technique at postnatal days (PND) 2, 8, 15, and 22. The PND protein ratios were calculated using Proteome Discoverer, and the PND protein change profiles were constructed separately for male and female animals for key presynaptic, postsynaptic, and adhesion brain proteins. The profiles were compared to the analogous profiles assembled from the published mouse and rat cortex proteomic data, including the fractionated-synaptosome data. The PND protein-change trendlines, Pearson correlation coefficient (PCC), and linear regression analysis of the statistically significant PND protein changes were used in the comparative analysis of the datasets. The analysis identified similarities and differences between the datasets. Importantly, there were significant similarities in the comparison of the rat cortex PND (current work) vs mouse (previously published) PND profiles, although in general, a lower abundance of synaptic proteins in mice than in rats was found. The male and female rat cortex PND profiles were expectedly almost identical (98-99% correlation by PCC), which also substantiated this LFQ nanoflow liquid chromatography-high-resolution mass spectrometry approach.

Increasing emergency number utilisation is not driven by low-acuity calls: an observational study of 1.5 million emergency calls (2018-2021) from Berlin.

BACKGROUND: The Emergency Medical Service (EMS) in Germany is increasingly challenged by strongly rising demand. Speculations about a greater utilisation for minor cases have led to intensive media coverage, but empirical evidence is lacking. We investigated the development of low-acuity calls from 2018 to 2021 in the federal state of Berlin and its correlations with sociodemographic characteristics. METHODS: We analysed over 1.5 million call documentations including medical dispatch codes, age, location and time using descriptive and inferential statistics and multivariate binary logistic regression. We defined a code list to classify low-acuity calls and merged the dataset with sociodemographic indicators and data on population density. RESULTS: The number of emergency calls (phone number 112 in Germany) increased by 9.1% from 2018 to 2021; however, the proportion of low-acuity calls did not increase. The regression model shows higher odds of low-acuity for young to medium age groups (especially for age 0-9, OR 1.50 [95% CI 1.45-1.55]; age 10-19, OR 1.77 [95% CI 1.71-1.83]; age 20-29, OR 1.64 [95% CI 1.59-1.68] and age 30-39, OR 1.40 [95% CI 1.37-1.44]; p < 0.001, reference group 80-89) and for females (OR 1.12 [95% CI 1.1-1.13], p < 0.001). Odds were slightly higher for calls from a neighbourhood with lower social status (OR 1.01 per index unit increase [95% CI 1.0-1.01], p < 0.05) and at the weekend (OR 1.02 [95% CI 1.0-1.04, p < 0.05]). No significant association of the call volume with population density was detected. CONCLUSIONS: This analysis provides valuable new insights into pre-hospital emergency care. Low-acuity calls were not the primary driver of increased EMS utilisation in Berlin. Younger age is the strongest predictor for low-acuity calls in the model. The association with female gender is significant, while socially deprived neighbourhoods play a minor role. No statistically significant differences in call volume between densely and less densely populated regions were detected. The results can inform the EMS in future resource planning.

In vivo neurophysiological assessment of in silico predictions of neurotoxicity: Citronellal, 3,4-dichloro-1-butene, and benzyl bromoacetate.

Neurotoxicants may be widespread in the environment and can produce serious health impacts in the human population. Screening programs that use in vitro methods have generated data for thousands of chemicals. However, these methods often do not evaluate repeated or prolonged exposures, which are required for many neurotoxic outcomes. Additionally, the data produced by such screening methods may not include mechanisms which play critical biological roles necessary for in vivo neurotoxicity. The Hard and Soft Acids and Bases (HSAB) in silico model focuses on chemical structure and electrophilic properties which are important to the formation of protein adducts. A group of structurally diverse chemicals have been evaluated with an in silico screening approach incorporating HSAB parameters. However, the predictions from the expanded chemical space have not been evaluated using in vivo methods. Three chemicals predicted to be cumulative toxicants were selected for in vivo neurotoxicological testing. Adult male Long-Evans rats were treated orally with citronellal (CIT), 3,4-dichloro-1-butene (DCB), or benzyl bromoacetate (BBA) for 8 weeks. Behavioral observations were recorded weekly to assess motor function. Peripheral neurophysiological measurements were derived from nerve excitability (NE) tests which involved compound muscle action potentials (CMAPs) in the tail and foot, and mixed nerve action potentials (MNAPs) in the tail. Compound nerve action potentials (CNAPs) and nerve conduction velocity (NCV) in the tail were also quantified. Peripheral inputs into the central nervous system were examined using somatosensory evoked potentials recorded from the cortex (SEPCTX) and cerebellum (SEPCEREB). CIT or BBA did not result in significant alterations to peripheral nerve or somatosensory function. DCB reduced grip-strength and altered peripheral nerve function. The MNAPs required less current to reach 50% amplitude and had a lower calculated rheobase, suggesting increased excitability. Increased CNAP amplitudes and greater NCV were also observed. Novel changes were found in the SEPCTX with an abnormal peak forming in the early portion of the waveforms of treated rats, and decreased latencies and increased amplitudes were observed in SEPCEREB recordings. These data contribute to testing an expanded chemical space from an in silico HSAB model for predicting cumulative neurotoxicity and may assist with prioritizing chemicals to protect human health.

Impacts of a perinatal exposure to manganese coupled with maternal stress in rats: Tests of untrained behaviors.

Manganese (Mn), an element that naturally occurs in the environment, has been shown to produce neurotoxic effects on the developing young when levels exceed physiological requirements. To evaluate the effects of this chemical in combination with non-chemical factors pregnant Long-Evans rats were treated with 0, 2, or 4 mg/mL Mn in their drinking water from gestational day (GD) 7 to postnatal day (PND) 22. Half of the dams received a variable stress protocol from GD13 to PND9, that included restraint, small cage with reduced bedding, exposure to predator odor, intermittent intervals of white noise, lights on for 24 h, intermittent intervals of lights on during dark cycle and cages with grid floors and reduced bedding. One male and one female offspring from each litter were tested to assess untrained behavior. Ultrasonic vocalizations (USV) were recorded from PND13 pups while they were isolated from the litter. Locomotor activity (MA) was measured in figure-eight mazes at PND 17, 29, and 79 (different set of rats at each time point). Social approach (SA) was tested at PND48. Acoustic startle response (ASR) and pre-pulse inhibition (PPI) were measured starting at PND58. At PND53 a sweetness preference for a chocolate flavored milk solution was assessed. There were sex related differences on several parameters for the USVs. There was also a Mn by stress by sex interaction with the females from the 4 mg/mL stressed dams having more frequency modulated (FM) call elements than the 4 mg/mL non-stressed group. There was an effect of Mn on motor activity but only at PND29 with the 2 mg/mL group having higher counts than the 0 mg/mL group. The social approach test showed sex differences for both the habituation and test phase. There was an effect of Mn, with the 4 mg/mL males having a greater preference for the stimulus rat than did the 0 mg/mL males. There was also a stress by sex interaction. The ASR and PPI had only a sex effect. Thus, with only the FM call elements having a Mn by stress effect, and the PND29 MA and SA preference index having a Mn effect but at different doses requires further investigation.

Impacts of a perinatal exposure to manganese coupled with maternal stress in rats: Maternal somatic measures and the postnatal growth and development of rat offspring.

Psychological stress experienced by the mother during pregnancy has been associated with emotional and cognitive disorders in children such as depression and anxiety. Socioeconomically disadvantaged populations are vulnerable to adverse life experiences and can also be disproportionally exposed to environmental contaminants. To better understand the neurodevelopmental impacts of an environmental toxicant coupled with elevated psychological stress, we exposed pregnant rats to a series of perinatal stressors. Manganese (Mn), a neurotoxicant at excessive concentrations was delivered through drinking water (0, 2, or 4 mg/mL) from gestational day (GD) 7 to postnatal day (PND) 22. A variable stress paradigm was applied to half of the animals from GD13 to PND9. Measurements of somatic development and behavior were examined in the offspring at different developmental stages. No evidence of overt maternal toxicity was observed although the 4 mg/mL Mn-exposed dams gained less body weight during gestation compared to the other dams. Stress also reduced gestational maternal weight gain. Daily fluid consumption normalized for body weight was decreased in the Mn-exposed dams in a dose-dependent manner but was not altered by the stress paradigm. Maternal stress and/or Mn exposure did not affect litter size or viability, but pup weight was significantly reduced in the 4 mg/mL Mn-exposed groups on PNDs 9 through 34 when compared to the other offspring groups. The efficacy of the manipulations to increase maternal stress levels was determined using serum corticosterone as a biomarker. The baseline concentration was established prior to treatment (GD7) and levels were low and similar in all treatment groups. Corticosterone levels were elevated in the perinatal-stress groups compared to the no-stress groups, regardless of Mn exposure, on subsequent time points (GD16, PND9), but were only significantly different on GD16. An analysis of tissue concentrations revealed Mn was elevated similarly in the brain and blood of offspring at PND2 and at PND22 in a significant dose-dependent pattern. Dams also showed a dose-dependent increase in Mn concentrations in the brain and blood; the addition of stress increased the Mn concentrations in the maternal blood but not the brain. Perinatal stress did not alter the effects of Mn on the maternal or offspring somatic endpoints described here.

The Future of Neurotoxicology: A Neuroelectrophysiological Viewpoint.

Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.

Mirror Therapy for Lower-Extremity Hemiparesis: A Knowledge Translation Study Using an Educational Module to Change Physiotherapists' Perceptions.

Purpose: Despite growing evidence that mirror therapy (MT) is effective for improving lower-extremity (LE) function in patients with stroke, it is not commonly used by physiotherapists. The purpose of this study was to determine whether change would occur in physiotherapists' knowledge of, confidence in performing, and willingness to use MT for LE stroke rehabilitation after participating in a 1-hour educational module. Method: A convenience sample of physiotherapists working in neurorehabilitation was recruited for a single-group quasi-experimental pre-post study. Participants attended a 1-hour educational module on MT. Therapists' perceptions of the use of MT were assessed by questionnaire before and after they participated in the module. A follow-up telephone survey was conducted after 3 months to determine how many participants had actually used MT in their practice. Results: Nine physiotherapists participated in this study. Statistically significant increases were found in their perceived knowledge of, confidence in, and willingness to use MT. At the 3-month follow-up, three participants had used MT with patients with LE hemiparesis. Conclusions: Therapists' knowledge of and attitudes toward MT for LE stroke rehabilitation changed favourably after participating in a 1-hour educational module. The module also led some therapists to make a change in practice at 3 months.

Objectif : malgré les données croissantes démontrant l'efficacité de la thérapie du miroir (TM) pour améliorer la fonction des extrémités inférieures (EL) chez les patients victimes d'un accident vasculaire cérébral (AVC), cette thérapie n'est pas d'usage courant chez les physiothérapeutes. La présente étude visait à établir si les physiothérapeutes accroissaient leurs connaissances de la TM pour la réadaptation des EI après un AVC ainsi que leur confiance et leur volonté à utiliser cette thérapie après avoir participé à un module de formation d'une heure. Méthodologie : les chercheurs ont recruté un échantillon de commodité de physiothérapeutes en neuroréadaptation en vue d'une étude avant-après quasi expérimentale d'un groupe unique. Les participants ont suivi un module de formation d'une heure sur la TM. Les chercheurs ont évalué la perception qu'avaient les physiothérapeutes de l'utilisation de la TM par questionnaire avant et après leur participation au module. Ils ont réalisé un sondage téléphonique trois mois plus tard pour déterminer le nombre de participants qui avaient vraiment intégré la TM à leur pratique. Résultats : neuf physiothérapeutes ont participé à la présente étude. Les chercheurs ont constaté des augmentations statistiquement significatives de la perception des connaissances, de la confiance et de la volonté d'utiliser la TM. Au bout de trois mois, trois participants avaient utilisé la TM chez des patients présentant une hémiparésie des EI. Conclusion : Les connaissances et les attitudes des thérapeutes relativement à la TM pour la réadaptation des EI après un AVC ont augmenté après un module de formation d'une heure. Ce module a également incité certains thérapeutes à apporter certains changements au bout de trois mois.

Exposure to Intermittent Noise Exacerbates the Cardiovascular Response of Wistar-Kyoto Rats to Ozone Inhalation and Arrhythmogenic Challenge.

Noise has become a prevalent public health problem across the world. Although there is a significant amount of data demonstrating the harmful effects of noise on the body, very little is known about how it impacts subsequent responses to other environmental stressors like air pollution, which tend to colocalize in urban centers. Therefore, this study was conducted to determine the effect of intermittent noise on cardiovascular function and subsequent responses to ozone (O3). Male Wistar-Kyoto rats implanted with radiotelemeters to non-invasively measure heart rate (HR) and blood pressure (BP), and assess heart rate variability (HRV) and baroreflex sensitivity (BRS) were kept in the quiet or exposed to intermittent white noise (85-90 dB) for one week and then exposed to either O3 (0.8 ppm) or filtered air. Left ventricular function and arrhythmia sensitivity were measured 24 h after exposure. Intermittent noise caused an initial increase in HR and BP, which decreased significantly later in the regimen and coincided with an increase in HRV and BRS. Noise caused HR and BP to be significantly elevated early during O3 and lower at the end when compared to animals kept in the quiet while the increased HRV and BRS persisted during the 24 h after. Lastly, noise increased arrhythmogenesis and may predispose the heart to mechanical function changes after O3. This is the first study to demonstrate that intermittent noise worsens the cardiovascular response to inhaled O3. These effects may occur due to autonomic changes and dysregulation of homeostatic controls, which persist one day after exposure to noise. Hence, co-exposure to noise should be taken into account when assessing the health effects of urban air pollution.

Acute in vitro effects on embryonic rat dorsal root ganglion (DRG) cultures by in silico predicted neurotoxic chemicals: Evaluations on cytotoxicity, neurite length, and neurophysiology.

The Hard-Soft Acid and Base hypothesis can be used to predict the potential bio-reactivity (electrophilicity) of a chemical with intracellular proteins, resulting in neurotoxicity. Twelve chemicals predicted to be neurotoxic were evaluated in vitro in rat dorsal root ganglia (DRG) for effects on cytotoxicity (%LDH), neuronal structure (total neurite length/neuron, NLPN), and neurophysiology (mean firing rate, MFR). DRGs were treated acutely on days in vitro (DIV) 7 (1-100 µM) with test chemical; %LDH and NLPN were measured after 48 h. 4-cyclohexylhexanone (4-C) increased %LDH release at 50 (29%) and 100 µM (56%), citronellal (Cit) and 1-bromopropane increased %LDH at 100 µM (22% and 26%). 4-C, Cit, 2,5 Hexanedione (2,5Hex), phenylacetylaldehyde (PAA) and 2-ethylhexanal decreased mean NLPN at 48 h; 50 and 100 µM for 4-C (28% and 60%), 100 µM Cit (52%), 100 µM 2,5- Hex (37%) 100 µM PAA (41%) and 100 µM for 2-ethylhexanal (23%). Separate DRG cultures were treated on DIV 14 and changes in MFR measured. Four compounds decreased MFR at 50 or 100 µM: Acrylamide (-83%), 3,4-dichloro-1-butene (-93%), 4-C (-89%) and hexane (-79%, 50 µM). Changes in MFR and NLPN occurred in absence of cytotoxicity. While the current study showed little cytotoxicity, it gave insight to initial changes in MFR. Results provide insight for future chronic exposure experiments to evaluate neurotoxicity.

Application of the hard and soft, acids and bases (HSAB) theory as a method to predict cumulative neurotoxicity.

Xenobiotic electrophiles can form covalent adducts that may impair protein function, damage DNA, and may lead a range of adverse effects. Cumulative neurotoxicity is one adverse effect that has been linked to covalent protein binding as a Molecular Initiating Event (MIE). This paper describes a mechanistic in silico chemical screening approach for neurotoxicity based on Hard and Soft Acids and Bases (HSAB) theory. We evaluated the applicability of HSAB-based electrophilicity screening protocol for neurotoxicity on 19 positive and 19 negative reference chemicals. These reference chemicals were identified from the literature, using available information on mechanisms of neurotoxicity whenever possible. In silico screening was based on structural alerts for protein binding motifs and electrophilicity index in the range of known neurotoxicants. The approach demonstrated both a high positive prediction rate (82-90 %) and specificity (90 %). The overall sensitivity was relatively lower (47 %). However, when predicting the toxicity of chemicals known or suspected of acting via non-specific adduct formation mechanism, the HSAB approach identified 7/8 (sensitivity 88 %) of positive control chemicals correctly. Consequently, the HSAB-based screening is a promising approach of identifying possible neurotoxins with adduct formation molecular initiating events. While the approach must be expanded over time to capture a wider range of MIEs involved in neurotoxicity, the mechanistic nature of the screen allows users to flag chemicals for possible adduct formation MIEs. Thus, the HSAB based toxicity screening is a promising strategy for toxicity assessment and chemical prioritization in neurotoxicology and other health endpoints that involve adduct formation.

Generativity and other buffers of death awareness in first responders.

Background and Objectives: Anxiety buffer disruption theory (ABDT) predicts that posttraumatic stress reactions occur when buffers of awareness of death, such as meaning in life, self-esteem, and social intimacy, fail to suppress overwhelming death-anxiety. In this study, we hypothesized that generativity may also serve as an effective buffer of awareness of death and posttraumatic stress disorder (PTSD).Design: The present study investigated the presence of anxiety buffering disruption in first responders with a spectrum of posttraumatic stress via a mediation path model of self-report measures of PTSD symptoms, anxiety buffer variables, and death-thought accessibility.Methods: To investigate the role of anxiety buffering in PTSD, a sample of 986 first responders completed self-report measures of PTSD symptoms and anxiety buffer variables in randomized order, and a death-thought accessibility measure following random assignment to mortality salience (n = 290) or control (n = 302) conditioning.Results and Conclusion: Results of structural equation modeling indicated PTSD symptoms have a small relation to increased awareness of death whereas anxiety buffering variables did not mediate the relation between PTSD symptoms and awareness of death. Nonetheless, generativity and meaning in life, self-esteem, and social support were significant predictors of lower levels of PTSD.

[Data sources on sick pay in the German health care system: An overview and recommendations for health services research]. / Datenquellen zum Krankengeld im deutschen Gesundheitswesen ­ eine Übersicht sowie Empfehlungen für die Versorgungsforschung.

BACKGROUND: Various data sources on sick pay exist in the German health care system. For future analyses, it is relevant to know which data sources are suitable for which research questions, which variables they include, how they can be accessed and which limitations are to be considered. This article offers a comprehensive overview. METHODS: The German Advisory Council on the Assessment of Developments in the Health Care System used various data sources for its special report on sick pay. For this purpose, several individual agreements with institutions have been made. Insights from these analyses have been systematically analysed and described. RESULTS: Important data sources on sick pay and sick pay recipients include the official statistics hosted by the Federal Ministry of Health and the data of single sickness funds. Moreover, the dataset of the morbidity-oriented risk structure compensation scheme includes some information on sick pay - partly on a regional level. Furthermore, data on cases of long-term incapacity to work, e. g. from the AOK sickness funds, can be used as an approximation for sick pay cases. The available data sources differ regarding available variables, data format, available time course and representativeness. DISCUSSION AND CONCLUSION: Which data source is most suitable for analyses of sick pay and sick pay recipients, strongly depends on the research question. There may be a trade-off between depth and applicable analytical methods on the one hand (e. g. with data of single sickness funds) versus representativeness and a long-term course on the other hand (e. g. with official statistics). Finally, several recommendations are made on how to further improve the informative value and comparability of data, especially among sickness funds.

Changes in the metabolome and microRNA levels in biological fluids might represent biomarkers of neurotoxicity: A trimethyltin study.

Neurotoxicity has been linked with exposure to a number of common drugs and chemicals, yet efficient, accurate, and minimally invasive methods to detect it are lacking. Fluid-based biomarkers such as those found in serum, plasma, urine, and cerebrospinal fluid have great potential due to the relative ease of sampling but at present, data on their expression and translation are lacking or inconsistent. In this pilot study using a trimethyl tin rat model of central nervous system toxicity, we have applied state-of-the-art assessment techniques to identify potential individual biomarkers and patterns of biomarkers in serum, plasma, urine or cerebral spinal fluid that may be indicative of nerve cell damage and degeneration. Overall changes in metabolites and microRNAs were observed in biological fluids that were associated with neurotoxic damage induced by trimethyl tin. Behavioral changes and magnetic resonance imaging T2 relaxation and ventricle volume changes served to identify animals that responded to the adverse effects of trimethyl tin. Impact statement These data will help design follow-on studies with other known neurotoxicants to be used to assess the broad applicability of the present findings. Together this approach represents an effort to begin to develop and qualify a set of translational biochemical markers of neurotoxicity that will be readily accessible in humans. Such biomarkers could prove invaluable for drug development research ranging from preclinical studies to clinical trials and may prove to assist with monitoring of the severity and life cycle of brain lesions.

Commentary on topic: Should all tests of cognitive function - Learning, memory, attention - Be eliminated from the required protocols for developmental neurotoxicity testing?

The attached manuscript by Dr. Herr is a Commentary on Topic: Should All Tests of Cognitive Function - Learning, Memory, Attention - be Eliminated From the Required Protocols for Developmental Neurotoxicity Testing?

mGluR-mediated calcium signalling in the thalamic reticular nucleus.

The thalamic reticular nucleus (TRN) plays a major role in modulating the transfer of information from the thalamus to the cortex. GABAergic inhibition via the TRN is differentially regulated by metabotropic glutamate receptors (mGluRs) and the effect of mGluRs on the membrane potential, on ion channels, and on the plasticity of electrical coupling of TRN neurons has been studied previously. Although mGluRs are generally known to trigger Ca(2+) transients, mGluR-mediated Ca(2+)-transients in TRN neurons have not yet been investigated. In this study, we show that mGluRs can trigger Ca(2+)-transients in TRN neurons, that these transients depend on intracellular Ca(2+)-stores, and are mediated by IP3 receptors. Ca(2+) transients caused by the group I mGluR agonist DHPG elicit a current that is sensitive to flufenamic acid and has a reversal potential around -40mV. Our results add mGluR-mediated Ca(2+)-signalling in the TRN to the state-dependent modulators of the thalamocortical system.

Advance (Meta-) Directives for Patients with Dementia who Appear Content: Learning from a Nationwide Survey.

OBJECTIVES: Whether health care professionals should respect a properly executed advance directive (AD) refusing life support in late-stage dementia even if the patient seems contented, is an ethically contested issue. We undertook a nationwide survey to assess this problem and to test a practical solution. DESIGN: Nationwide survey using a questionnaire among 4 stakeholder groups. SETTING: Germany. PARTICIPANTS: Adult Germans (n = 735), among them: dementia-experienced physicians (n = 161), dementia-experienced nurses (n = 191), next of kin (n = 197), and dementia-inexperienced adults (n = 186). MEASUREMENTS: Participants were asked about their attitudes on medical decision-making in a vignette case of treatable pneumonia, for their agreement or disagreement on standard ethical arguments in this debate, and for their views on modified versions of the case. One such modification was an explicit anticipation of the conflict in question by the patients themselves. RESULTS: Of our 735 eligible respondents, 25% were unwilling to follow the patient's AD. Standard arguments for and against respecting the directive were endorsed to different degrees. Respondents' unwillingness to follow the directive was significantly decreased (to 16.3%, P < .001), if the advance refusal of pneumonia treatment explicitly indicated that it applied to a patient who appears content in his demented state. Only 8.7% of respondents would disregard an advance refusal of tube feeding. CONCLUSIONS: Persons executing ADs forbidding life support in late-stage dementia run some risk that these will not be followed if they later appear "happy" in their dementia. It seems ethically and practically advisable to incorporate an explicit meta-directive for this conflict.

Taxonomic applicability of inflammatory cytokines in adverse outcome pathway (AOP) development.

Cytokines, low-molecular-weight messenger proteins that act as intercellular immunomodulatory signals, have become a mainstream preclinical marker for assessing the systemic inflammatory response to external stressors. The challenge is to quantitate from healthy subjects cytokine levels that are below or at baseline and relate those dynamic and complex cytokine signatures of exposures with the inflammatory and repair pathways. Thus, highly sensitive, specific, and precise analytical and statistical methods are critically important. Investigators at the U.S. Environmental Protection Agency (EPA) have implemented advanced technologies and developed statistics for evaluating panels of inflammatory cytokines in human blood, exhaled breath condensate, urine samples, and murine biological media. Advanced multiplex, bead-based, and automated analytical platforms provided sufficient sensitivity, precision, and accuracy over the traditional enzyme-linked immunosorbent assay (ELISA). Thus, baseline cytokine levels can be quantified from healthy human subjects and animals and compared to an in vivo exposure response from an environmental chemical. Specifically, patterns of cytokine responses in humans exposed to environmental levels of ozone and diesel exhaust, and in rodents exposed to selected pesticides (such as fipronil and carbaryl), were used as case studies to generally assess the taxonomic applicability of cytokine responses. The findings in this study may aid in the application of measureable cytokine markers in future adverse outcome pathway (AOP)-based toxicity testing. Data from human and animal studies were coalesced and the possibility of using cytokines as key events (KE) to bridge species responses to external stressors in an AOP-based framework was explored.

Neurophysiological assessment of auditory, peripheral nerve, somatosensory, and visual system function after developmental exposure to gasoline, E15, and E85 vapors.

The use of gasolines blended with a range of ethanol concentrations may result in inhalation of vapors containing a variable combination of ethanol with other volatile gasoline constituents. The possibility of exposure and potential interactions between vapor constituents suggests the need to evaluate the possible risks of this complex mixture. Previously we evaluated the effects of developmental exposure to ethanol vapors on neurophysiological measures of sensory function as a component of a larger project evaluating developmental ethanol toxicity. Here we report an evaluation using the same battery of sensory function testing in offspring of pregnant dams exposed during gestation to condensed vapors of gasoline (E0), gasoline blended with 15% ethanol (E15) or gasoline blended with 85% ethanol (E85). Pregnant Long-Evans rats were exposed to target concentrations 0, 3000, 6000, or 9000 ppm total hydrocarbon vapors for 6.5h/day over GD9 - GD20. Sensory evaluations of male offspring began as adults. The electrophysiological testing battery included tests of: peripheral nerve (compound action potentials, nerve conduction velocity [NCV]), somatosensory (cortical and cerebellar evoked potentials), auditory (brainstem auditory evoked responses), and visual functions. Visual function assessment included pattern elicited visual evoked potentials (VEP), VEP contrast sensitivity, dark-adapted (scotopic) electroretinograms (ERGs), light-adapted (photopic) ERGs, and green flicker ERGs. The results included sporadic statistically significant effects, but the observations were not consistently concentration-related and appeared to be statistical Type 1 errors related to multiple dependent measures evaluated. The exposure concentrations were much higher than can be reasonably expected from typical exposures to the general population during refueling or other common exposure situations. Overall the results indicate that gestational exposure of male rats to ethanol/gasoline vapor combinations did not cause detectable changes in peripheral nerve, somatosensory, auditory, or visual function when the offspring were assessed as adults.

Translational Biomarkers of Neurotoxicity: A Health and Environmental Sciences Institute Perspective on the Way Forward.

Neurotoxicity has been linked to a number of common drugs and chemicals, yet efficient and accurate methods to detect it are lacking. There is a need for more sensitive and specific biomarkers of neurotoxicity that can help diagnose and predict neurotoxicity that are relevant across animal models and translational from nonclinical to clinical data. Fluid-based biomarkers such as those found in serum, plasma, urine, and cerebrospinal fluid (CSF) have great potential due to the relative ease of sampling compared with tissues. Increasing evidence supports the potential utility of fluid-based biomarkers of neurotoxicity such as microRNAs, F2-isoprostanes, translocator protein, glial fibrillary acidic protein, ubiquitin C-terminal hydrolase L1, myelin basic protein, microtubule-associated protein-2, and total tau. However, some of these biomarkers such as those in CSF require invasive sampling or are specific to one disease such as Alzheimer's, while others require further validation. Additionally, neuroimaging methodologies, including magnetic resonance imaging, magnetic resonance spectroscopy, and positron emission tomography, may also serve as potential biomarkers and have several advantages including being minimally invasive. The development of biomarkers of neurotoxicity is a goal shared by scientists across academia, government, and industry and is an ideal topic to be addressed via the Health and Environmental Sciences Institute (HESI) framework which provides a forum to collaborate on key challenging scientific topics. Here we utilize the HESI framework to propose a consensus on the relative potential of currently described biomarkers of neurotoxicity to assess utility of the selected biomarkers using a nonclinical model.