Injury patterns and mortality associated with near-hanging in children.

BACKGROUND: The pathophysiology of near-hanging in children is different from that of adults due to anatomic, physiologic, and injury-related mechanisms, with evidence suggesting that blunt cerebrovascular injuries (BCVI) and cervical spine injuries (CSI) are uncommon. We sought to estimate the incidence of secondary injuries and their association with mortality in pediatric near-hanging victims. METHODS: We performed a retrospective observational study of children (≤17 years) with a diagnosis code for hanging between October 1, 2015 and February 28, 2023 who presented to one of 47 geographically diverse US children's hospitals. We evaluated the incidence of the following secondary injuries: cerebral edema, pneumothorax, pulmonary edema, BCVI, and CSI. We performed Fisher's exact test with Bonferroni correction to identify associations between intentionality, sex, age, and secondary injuries with mortality. RESULTS: We included 1929 children, of whom 33.8% underwent neuroimaging, 45.9% underwent neck imaging, and 38.7% underwent neck angiography. The most common injury was cerebral edema (24.0%), followed by pulmonary edema (3.2%) and pneumothorax (2.8%). CSI (2.1%) and BCVI (0.9%) occurred infrequently. Cerebral edema, pneumothorax, pulmonary edema, and younger age (≤12 years) were associated with mortality. CONCLUSIONS: In this multi-center study of pediatric near-hanging victims, BCVI and CSI occurred rarely and were not associated with mortality. While children in our study underwent neck imaging more frequently than head imaging, cerebral edema occurred more often than other injury types and imparted the highest mortality risk. Given the rarity of BCVI and CSI, a selective approach to neck imaging may be warranted in pediatric near-hanging events.

Novel Insights into Changes in Gene Expression within the Hypothalamus in Two Asthma Mouse Models: A Transcriptomic Lung-Brain Axis Study.

Patients with asthma experience elevated rates of mental illness. However, the molecular links underlying such lung-brain crosstalk remain ambiguous. Hypothalamic dysfunction is observed in many psychiatric disorders, particularly those with an inflammatory component due to many hypothalamic regions being unprotected by the blood-brain barrier. To gain a better insight into such neuropsychiatric sequelae, this study investigated gene expression differences in the hypothalamus following lung inflammation (asthma) induction in mice, using RNA transcriptome profiling. BALB/c mice were challenged with either bacterial lipopolysaccharide (LPS, E. coli) or ovalbumin (OVA) allergens or saline control (n = 7 per group), and lung inflammation was confirmed via histological examination of postmortem lung tissue. The majority of the hypothalamus was micro-dissected, and total RNA was extracted for sequencing. Differential expression analysis identified 31 statistically significant single genes (false discovery rate FDR5%) altered in expression following LPS exposure compared to controls; however, none were significantly changed following OVA treatment, suggesting a milder hypothalamic response. When gene sets were examined, 48 were upregulated and 8 were downregulated in both asthma groups relative to controls. REACTOME enrichment analysis suggests these gene sets are involved in signal transduction metabolism, immune response and neuroplasticity. Interestingly, we identified five altered gene sets directly associated with neurotransmitter signaling. Intriguingly, many of these altered gene sets can influence mental health and or/neuroinflammation in humans. These findings help characterize the links between asthma-induced lung inflammation and the brain and may assist in identifying relevant pathways and therapeutic targets for future intervention.

Prevalence and Characteristics of Diagnostic Error in Pediatric Critical Care: A Multicenter Study.

OBJECTIVES: Effective interventions to prevent diagnostic error among critically ill children should be informed by diagnostic error prevalence and etiologies. We aimed to determine the prevalence and characteristics of diagnostic errors and identify factors associated with error in patients admitted to the PICU. DESIGN: Multicenter retrospective cohort study using structured medical record review by trained clinicians using the Revised Safer Dx instrument to identify diagnostic error (defined as missed opportunities in diagnosis). Cases with potential errors were further reviewed by four pediatric intensivists who made final consensus determinations of diagnostic error occurrence. Demographic, clinical, clinician, and encounter data were also collected. SETTING: Four academic tertiary-referral PICUs. PATIENTS: Eight hundred eighty-two randomly selected patients 0-18 years old who were nonelectively admitted to participating PICUs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 882 patient admissions, 13 (1.5%) had a diagnostic error up to 7 days after PICU admission. Infections (46%) and respiratory conditions (23%) were the most common missed diagnoses. One diagnostic error caused harm with a prolonged hospital stay. Common missed diagnostic opportunities included failure to consider the diagnosis despite a suggestive history (69%) and failure to broaden diagnostic testing (69%). Unadjusted analysis identified more diagnostic errors in patients with atypical presentations (23.1% vs 3.6%, p = 0.011), neurologic chief complaints (46.2% vs 18.8%, p = 0.024), admitting intensivists greater than or equal to 45 years old (92.3% vs 65.1%, p = 0.042), admitting intensivists with more service weeks/year (mean 12.8 vs 10.9 wk, p = 0.031), and diagnostic uncertainty on admission (77% vs 25.1%, p < 0.001). Generalized linear mixed models determined that atypical presentation (odds ratio [OR] 4.58; 95% CI, 0.94-17.1) and diagnostic uncertainty on admission (OR 9.67; 95% CI, 2.86-44.0) were significantly associated with diagnostic error. CONCLUSIONS: Among critically ill children, 1.5% had a diagnostic error up to 7 days after PICU admission. Diagnostic errors were associated with atypical presentations and diagnostic uncertainty on admission, suggesting possible targets for intervention.

Cytokine-inducible SH2 domain containing protein contributes to regulation of adiposity, food intake, and glucose metabolism.

The cytokine-inducible SH2 domain containing protein (CISH) is the founding member of the suppressor of cytokine signaling (SOCS) family of negative feedback regulators and has been shown to be a physiological regulator of signaling in immune cells. This study sought to investigate novel functions for CISH outside of the immune system. Mice deficient in CISH were generated and analyzed using a range of metabolic and other parameters, including in response to a high fat diet and leptin administration. CISH knockout mice possessed decreased body fat and showed resistance to diet-induced obesity. This was associated with reduced food intake, but unaltered energy expenditure and microbiota composition. CISH ablation resulted in reduced basal expression of the orexigenic Agrp gene in the arcuate nucleus (ARC) region of the brain. Cish was basally expressed in the ARC, with evidence of co-expression with the leptin receptor (Lepr) gene in Agrp-positive neurons. CISH-deficient mice also showed enhanced leptin responsiveness, although Cish expression was not itself modulated by leptin. CISH-deficient mice additionally exhibited improved insulin sensitivity on a high-fat diet, but not glucose tolerance despite reduced body weight. These data identify CISH as an important regulator of homeostasis through impacts on appetite control, mediated at least in part by negative regulation of the anorexigenic effects of leptin, and impacts on glucose metabolism.

Serum Biomarkers of Regeneration and Plasticity are Associated with Functional Outcome in Pediatric Neurocritical Illness: An Exploratory Study.

BACKGROUND/OBJECTIVE: Pediatric neurocritical care survivorship is frequently accompanied by functional impairments. Lack of prognostic biomarkers is a barrier to early identification and management of impairment. We explored the association between blood biomarkers and functional impairment in children with acute acquired brain injury. METHODS: This study is a secondary analysis of a randomized control trial evaluating early versus usual care rehabilitation in the pediatric intensive care unit (PICU). Forty-four children (17 [39%] female, median age 11 [interquartile range 6-13] years) with acute acquired brain injury admitted to the PICU were studied. A single center obtained serum samples on admission days 0, 1, 3, 5, and the day closest to hospital discharge. Biomarkers relevant to brain injury (neuron specific enolase [NSE], S100b), inflammation (interleukin [IL-6], C-reactive protein), and regeneration (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor [VEGF]) were collected. Biomarkers were analyzed using a Luminex® bioassay. Functional status scale (FSS) scores were abstracted from the medical record. New functional impairment was defined as a (worse) FSS score at hospital discharge compared to pre-PICU (baseline). Individual biomarker fluorescence index (FI) values for each sample collection day were correlated with new functional impairment using Spearman rank correlation coefficient (ρ). Trends in repeated measures of biomarker FI over time were explored graphically, and the association between repeated measures of biomarker FI and new functional impairment was analyzed using covariate adjusted linear mixed-effect models. RESULTS: Functional impairment was inversely correlated with markers of regeneration and plasticity including BDNF at day 3 (ρ = - 0.404, p = .015), day 5 (ρ = - 0.549, p = 0.005) and hospital discharge (ρ = - 0.420, p = 0.026) and VEGF at day 1 (ρ = - 0.282, p = 0.008) and hospital discharge (ρ = - 0.378, p = 0.047), such that lower levels of both markers at each time point were associated with greater impairment. Similarly, repeated measures of BDNF and VEGF were inversely correlated with new functional impairment (B = - 0.001, p = 0.001 and B = - 0.001, p = 0.003, respectively). NSE, a biomarker of acute brain injury, showed a positive correlation between day 0 levels and new functional impairment (ρ = 0.320, p = 0.044). CONCLUSIONS: Blood-based biomarkers of regeneration and plasticity may hold prognostic utility for functional impairment among pediatric patients with neurocritical illness and warrant further investigation.

Pioglitazone and Deoxyribonucleoside Combination Treatment Increases Mitochondrial Respiratory Capacity in m.3243A>G MELAS Cybrid Cells.

The lack of effective treatments for mitochondrial disease has seen the development of new approaches, including those that aim to stimulate mitochondrial biogenesis to boost ATP generation above a critical disease threshold. Here, we examine the effects of the peroxisome proliferator-activated receptor γ (PPARγ) activator pioglitazone (PioG), in combination with deoxyribonucleosides (dNs), on mitochondrial biogenesis in cybrid cells containing >90% of the m.3243A>G mutation associated with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). PioG + dNs combination treatment increased mtDNA copy number and mitochondrial mass in both control (CON) and m.3243A>G (MUT) cybrids, with no adverse effects on cell proliferation. PioG + dNs also increased mtDNA-encoded transcripts in CON cybrids, but had the opposite effect in MUT cybrids, reducing the already elevated transcript levels. Steady-state levels of mature oxidative phosphorylation (OXPHOS) protein complexes were increased by PioG + dNs treatment in CON cybrids, but were unchanged in MUT cybrids. However, treatment was able to significantly increase maximal mitochondrial oxygen consumption rates and cell respiratory control ratios in both CON and MUT cybrids. Overall, these findings highlight the ability of PioG + dNs to improve mitochondrial respiratory function in cybrid cells containing the m.3243A>G MELAS mutation, as well as their potential for development into novel therapies to treat mitochondrial disease.

Modulation of high fat diet-induced microbiome changes, but not behaviour, by minocycline.

An emerging novel therapeutic agent for major depressive disorder, minocycline, has the potential to influence both gut microbiome and inflammatory status. The present study showed that chronic high fat diet feeding led to changes in both behaviour and the gut microbiome in male mice, without an overt inflammatory response. The diet-induced behavioural changes were characterised as increased immobility in the forced swim test and changes in locomotor activities in the open field test. Minocycline significantly altered the gut microbiome, rendering a community distinctly different to both untreated healthy and diet-affected states. In contrast, minocycline did not reverse high fat diet-induced changes in behaviour.

PICU-Based Rehabilitation and Outcomes Assessment: A Survey of Pediatric Critical Care Physicians.

OBJECTIVES: Characterize current practices for PICU-based rehabilitation, and physician perceptions and attitudes, barriers, resources, and outcome assessment in contemporary PICU settings. DESIGN: International, self-administered, quantitative, cross-sectional survey. SETTING: Online survey distributed from March 2017 to April 2017. PATIENTS OR SUBJECTS: Pediatric critical care physicians who subscribed to email distribution lists of the Pediatric Acute Lung Injury and Sepsis Investigators, the Pediatric Neurocritical Care Research Group, or the Prevalence of Acute Critical Neurological Disease in Children: A Global Epidemiological Assessment study group, and visitors to the World Federation of Pediatric Intensive and Critical Care Societies website. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 170 subjects who began the survey, 148 completed it. Of those who completed the optional respondent information, most reported working in an academic medical setting and were located in the United States. The main findings were 1) a large majority of PICU physicians reported working in institutions with no guidelines for PICU-based rehabilitation, but expressed interest in developing and implementing such guidelines; 2) despite this lack of guidelines, an overwhelming majority of respondents reported that their current practices would involve consultation of multiple rehabilitation services for each case example provided; 3) PICU physicians believed that additional research evidence is needed to determine efficacy and optimal implementation of PICU-based rehabilitation; 4) PICU physicians reported significant barriers to implementation of PICU-based rehabilitation across centers; and 5) low routine assessment of long-term functional outcomes of PICU patients, although some centers have developed multidisciplinary follow-up programs. CONCLUSIONS: Physicians lack PICU-based rehabilitation guidelines despite great interest and current practices involving a high degree of PICU-based rehabilitation consultation. Data are needed to identify best practices and necessary resources in the delivery of ICU-based multidisciplinary rehabilitation and long-term functional outcomes assessment to optimize recovery of children and families affected by critical illness.

Early Protocolized Versus Usual Care Rehabilitation for Pediatric Neurocritical Care Patients: A Randomized Controlled Trial.

OBJECTIVE: s: Few feasibility, safety, and efficacy data exist regarding ICU-based rehabilitative services for children. We hypothesized that early protocolized assessment and therapy would be feasible and safe versus usual care in pediatric neurocritical care patients. DESIGN: Randomized controlled trial. SETTING: Three tertiary care PICUs in the United States. PATIENTS: Fifty-eight children between the ages of 3-17 years with new traumatic or nontraumatic brain insult and expected ICU admission greater than 48 hours. INTERVENTIONS: Early protocolized (consultation of physical therapy, occupational therapy, and speech and language therapy within 72 hr ICU admission, n = 26) or usual care (consultation per treating team, n = 32). MEASUREMENTS AND MAIN RESULTS: Primary outcomes were consultation timing, treatment type, and frequency of deferrals and safety events. Secondary outcomes included patient and family functional and quality of life outcomes at 6 months. Comparing early protocolized (n = 26) and usual care groups (n = 32), physical therapy was consulted during the hospital admission in 26 of 26 versus 28 of 32 subjects (p = 0.062) on day 2.4 ± 0.8 versus 7.7 ± 4.8 (p = 0.001); occupational therapy in 26 of 26 versus 23 of 32 (p = 0.003), on day 2.3 ± 0.6 versus 6.9 ± 4.8 (p = 0.001); and speech and language therapy in 26 of 26 versus 17 of 32 (p = 0.011) on day 2.3 ± 0.7 versus 13.0 ± 10.8 (p = 0.026). More children in the early protocolized group had consults and treatments occur in the ICU versus ward for all three services (all p < 0.001). Eleven sessions were discontinued early: nine during physical therapy and two during occupational therapy, none impacting patient outcome. There were no group differences in functional or quality of life outcomes. CONCLUSIONS: A protocol for early personalized rehabilitation by physical therapy, occupational therapy, and speech and language therapy in pediatric neurocritical care patients could be safely implemented and led to more ICU-based treatment sessions, accelerating the temporal profile and changing composition of interventions versus usual care, but not altering the total dose of rehabilitation.

Endogenous central amygdala mu-opioid receptor signaling promotes sodium appetite in mice.

Due to the importance of dietary sodium and its paucity within many inland environments, terrestrial animals have evolved an instinctive sodium appetite that is commensurate with sodium deficiency. Despite a well-established role for central opioid signaling in sodium appetite, the endogenous influence of specific opioid receptor subtypes within distinct brain regions remains to be elucidated. Using selective pharmacological antagonists of opioid receptor subtypes, we reveal that endogenous mu-opioid receptor (MOR) signaling strongly drives sodium appetite in sodium-depleted mice, whereas a role for kappa (KOR) and delta (DOR) opioid receptor signaling was not detected, at least in sodium-depleted mice. Fos immunohistochemistry revealed discrete regions of the mouse brain displaying an increased number of activated neurons during sodium gratification: the rostral portion of the nucleus of the solitary tract (rNTS), the lateral parabrachial nucleus (LPB), and the central amygdala (CeA). The CeA was subsequently targeted with bilateral infusions of the MOR antagonist naloxonazine, which significantly reduced sodium appetite in mice. The CeA is therefore identified as a key node in the circuit that contributes to sodium appetite. Moreover, endogenous opioids, acting via MOR, within the CeA promote this form of appetitive behavior.

Salt Appetite, and the Influence of Opioids.

Due to the biological importance of sodium and its relative scarcity within many natural environments, 'salt appetite' has evolved whereby dietary salt is highly sought after and palatable when tasted. In addition to peripheral responses, salt depletion is detected within the brain via circumventricular organs and 11ß-hydroxysteroid dehydrogenase type 2 (HSD2) neurons to increase salt appetite. Salt appetite is comprised of two main components. One component is the incentive salience or motivation for salt (i.e. how much salt is 'wanted'). Incentive salience is dynamic and largely depends on internal homeostatic conditions in combination with the detection of relevant cues. It involves the mesolimbic system and structures such as the central amygdala, and opioid signalling within these regions can increase salt intake in rodents. A second key feature is the hedonic palatability of salt (i.e. how much it is 'liked') when it is tasted. After detection on the tongue, gustatory information passes through the brainstem nucleus of the solitary tract and thalamus, before being consciously detected within the gustatory cerebral cortex. The positive or negative hedonic value of this stimulus is also dynamic, and is encoded by a network including the nucleus accumbens, ventral pallidum, and lateral parabrachial nucleus. Opioid signalling within these areas can alter salt intake, and 'liking'. The overconsumption of dietary salt likely contributes to hypertension and associated diseases, and hence further characterising the role played by opioid signalling has important implications for human health.

Thermoregulate, autoregulate and ventilate: brain-directed critical care for pediatric cardiac arrest.

PURPOSE OF REVIEW: Cardiac arrest in childhood is associated with a high risk for mortality and poor long-term functional outcome. This review discusses the current evidence for neuroprotective therapies and goals for postarrest care in the context of the pathophysiology of hypoxic-ischemic injury, modalities for neurologic prognostication in these children and potential future monitoring paradigms for maximizing cerebral perfusion in the postarrest period. RECENT FINDINGS: The recent publication of the in-hospital and out-of-hospital Therapeutic Hypothermia After Cardiac Arrest trials demonstrated a lack of statistically significant benefit for the use of postarrest therapeutic hypothermia. As a result, targeted normothermic temperature management has become standard of care. Continuous electroencephalographic monitoring during the acute postarrest period provides useful additional data for neurologic prognostication, in addition to its value for detection of seizures. Ongoing research into noninvasive monitoring of cerebrovascular autoregulation has the potential to individualize blood pressure goals in the postarrest period, maximizing cerebral perfusion in these patients. SUMMARY: Therapeutic strategies after cardiac arrest seek to maximize cerebral perfusion while mitigating the effects of secondary brain injury and loss of autoregulation. Future research into new monitoring strategies and better long-term outcome measures may allow more precise targeting of therapies to these goals.

Nucleus incertus corticotrophin-releasing factor 1 receptor signalling regulates alcohol seeking in rats.

Alcoholism is a chronic relapsing disorder, and stress is a key precipitant of relapse. The nucleus incertus (NI) is highly responsive to corticotrophin-releasing factor (CRF) and psychological stressors, receives a CRF innervation and expresses CRF1 and CRF2 receptor mRNA. Furthermore, the ascending NI relaxin-3 system is implicated in alcohol seeking in rats. Therefore, in alcohol-preferring rats, we examined the effect of bilateral injections into the NI of the CRF1 receptor antagonist, CP376395 or the CRF2 receptor antagonist, astressin-2B on yohimbine-induced reinstatement of alcohol seeking. Using quantitative PCR analysis of NI micropunches, we assessed the effects of chronic alcohol consumption on gene expression profiles for components of the relaxin-3 and CRF systems. Bilateral intra-NI injections of CP376395 (500 ng/0.25 µl) attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injections of astressin-2B (200 ng/0.25 µl) had no significant effect. In line with these data, CRF1 , but not CRF2 , receptor mRNA was upregulated in the NI following chronic ethanol intake. Relaxin family peptide 3 receptor mRNA was also increased in the NI following chronic ethanol. Our quantitative PCR analysis also identified CRF mRNA within the rat NI, and the existence of a newly identified population of CRF-containing neurons was subsequently confirmed by detection of CRF immunoreactivity in rat and mouse NI. These data suggest that NI neurons contribute to reinstatement of alcohol seeking, via an involvement of CRF1 signalling. Furthermore, chronic ethanol intake leads to neuroadaptive changes in CRF and relaxin-3 systems within rat NI.

Transcranial Doppler Identification of Neurologic Injury during Pediatric Extracorporeal Membrane Oxygenation Therapy.

BACKGROUND: We used transcranial Doppler to examine changes in cerebral blood flow velocity in children treated with extracorporeal membrane oxygenation. We examined the association between those changes and radiologic, electroencephalographic, and clinical evidence of neurologic injury. METHODS: This was a retrospective review and prospective observational study of patients 18 years old and younger at a single university children's hospital. Transcranial Doppler studies were obtained every other day during the first 7 days of extracorporeal membrane oxygenation, and 1 additional study following decannulation, in conjunction with serial neurologic examinations, brain imaging, and 6- to 12-month follow-up. RESULTS: The study included 27 patients, the majority (26) receiving veno-arterial extracorporeal membrane oxygenation. Transcranial Doppler velocities during extracorporeal membrane oxygenation were significantly lower than published values for age-matched healthy and critically ill children across different cerebral arteries. Neonates younger than 10 days had higher velocities than expected. Blood flow velocity increased after extracorporeal membrane oxygenation decannulation and was comparable with age-matched critically ill children. There was no significant association between velocity measurements of individual arteries and acute neurologic injury as defined by either abnormal neurologic examination, seizures during admission, or poor pediatric cerebral performance category. However, case analysis identified several patients with regional and global increases in velocities that corresponded to neurologic injury including stroke and seizures. CONCLUSIONS: Cerebral blood flow velocities during extracorporeal membrane oxygenation deviate from age-specific normal values in all major cerebral vessels and across different age groups. Global or regional elevations and asymmetries in flow velocity may suggest impending neurologic injury.

Ischemia-induced autophagy contributes to neurodegeneration in cerebellar Purkinje cells in the developing rat brain and in primary cortical neurons in vitro.

Increased autophagy/mitophagy is thought to contribute to cerebellar dysfunction in Purkinje cell degeneration mice. Intriguingly, cerebellar Purkinje cells are highly vulnerable to hypoxia-ischemia (HI), related at least in part to their high metabolic activity. Whether or not excessive or supraphysiologic autophagy plays a role in Purkinje cell susceptibility to HI is unknown. Accordingly, we evaluated the role of autophagy in the cerebellum after global ischemia produced by asphyxial cardiac arrest in postnatal day (PND) 16-18 rats, using siRNA-targeted inhibition of Atg7, necessary for microtubule-associated protein light chain 3-II (LC3-II) and Atg12-Atg5 complex formation. Two days before a 9min asphyxial cardiac arrest or sham surgery, Atg7 or control siRNA was injected intracisternally to target the cerebellum. Treatment with Atg7 siRNA: 1) reduced Atg7 protein expression in the cerebellum by 56%; 2) prevented the typical ischemia-induced formation of LC3-II in the cerebellum 24h after asphyxial cardiac arrest; 3) improved performance on the beam-balance apparatus on days 1-5; and 4) increased calbindin-labeled Purkinje cell survival assessed on day 14. Improved Purkinje cell survival was more consistent in female vs. male rats, and improved beam-balance performance was only seen in female rats. Similar responses to Atg7 siRNA i.e. reduced autophagy and neurodegeneration vs. control siRNA were seen when exposing sex-segregated green fluorescent protein-LC3 tagged mouse primary cortical neurons to oxygen glucose deprivation in vitro. Thus, inhibition of autophagy after global ischemia in PND 16-18 rats leads to increased survival of Purkinje cells and improved motor performance in a sex-dependent manner.

Sensitivity to Chronic Methamphetamine Administration and Withdrawal in Mice with Relaxin-3/RXFP3 Deficiency.

Methamphetamine (METH) is a highly addictive psychostimulant, and cessation of use is associated with reduced monoamine signalling, and increased anxiety/depressive states. Neurons expressing the neuropeptide, relaxin-3 (RLN3), and its cognate receptor, RXFP3, constitute a putative 'ascending arousal system', which shares neuroanatomical and functional similarities with serotonin (5-HT)/dorsal raphe and noradrenaline (NA)/locus coeruleus monoamine systems. In light of possible synergistic roles of RLN3 and 5-HT/NA, endogenous RLN3/RXFP3 signalling may compensate for the temporary reduction in monoamine signalling associated with chronic METH withdrawal, which could alter the profile of 'behavioural despair', bodyweight reductions, and increases in anhedonia and anxiety-like behaviours observed following chronic METH administration. In studies to test this theory, Rln3 and Rxfp3 knockout (KO) mice and their wildtype (WT) littermates were injected once daily with saline or escalating doses of METH (2 mg/kg, i.p. on day 1, 4 mg/kg, i.p. on day 2 and 6 mg/kg, i.p. on day 3-10). WT and Rln3 and Rxfp3 KO mice displayed an equivalent sensitivity to behavioural despair (Porsolt swim) during the 2-day METH withdrawal and similar bodyweight reductions on day 3 of METH treatment. Furthermore, during a 3-week period after the cessation of chronic METH exposure, Rln3 KO, Rxfp3 KO and corresponding WT mice displayed similar behavioural responses in paradigms that measured anxiety (light/dark box, elevated plus maze), anhedonia (saccharin preference), and social interaction. These findings indicate that a whole-of-life deficiency in endogenous RLN3/RXFP3 signalling does not markedly alter behavioural sensitivity to chronic METH treatment or withdrawal, but leave open the possibility of a more significant interaction with global or localised manipulations of this peptide system in the adult brain.

Pediatric super-refractory status epilepticus treated with allopregnanolone.

Super-refractory status epilepticus is a life-threatening condition. Resistance to benzodiazepine and barbiturate treatment for this disorder is thought to be due to internalization of synaptic γ-aminobutyric acid (GABA)A receptors, and withdrawal of benzodiazepines and barbiturates during treatment often triggers seizure recurrence. The neurosteroid allopregnanolone acts as a positive allosteric modulator of synaptic and extrasynaptic GABAA receptors. Here we describe the use of allopregnanolone in 2 pediatric patients with super-refractory status epilepticus. This treatment allowed the general anesthetic infusions to be weaned with resolution of status epilepticus. This is the first report of allopregnanolone use to treat status epilepticus in children.

Involvement of central relaxin-3 signalling in sodium (salt) appetite.

NEW FINDINGS: What is the central question of this study? Sodium appetite is controlled by conserved neuronal transmitter-receptor systems. Here, we tested the contribution made by relaxin family peptide 3 receptor (RXFP3), the cognate G-protein-coupled receptor for the neuropeptide relaxin-3. What is the main finding and its importance? Intracerebroventricular infusion of an RXFP3 antagonist reduced in a dose-dependent manner the volume of 0.3 m NaCl consumed by sodium-depleted C57Bl/6J (wild-type) mice. This effect was absent in sodium-depleted Rxfp3 knockout mice, and RXFP3 antagonist infusion did not alter water consumption in wild-type mice subjected to multiple thirst tests, indicating both the pharmacological and the physiological specificity of observed effects. Our findings identify endogenous relaxin-3-RXFP3 signalling as a modulator of sodium appetite. Overconsumption of highly salted foods is common in Western diets and contributes significantly to metabolic disorders such as hypertension, renal dysfunction and diabetes. Sodium appetite, or the desire of terrestrial animals to seek and consume sodium-containing salts, is a behaviour mediated by a set of evolutionarily conserved neuronal systems. In these studies, we tested whether this instinctive behavioural drive is influenced by the G-protein-coupled relaxin family peptide 3 receptor (RXFP3), the cognate receptor for the neuropeptide relaxin-3, because relaxin-3-RXFP3 signalling can modulate arousal, motivation and ingestive behaviours. Intracerebroventricular (i.c.v.) infusion of the selective RXFP3 antagonist, R3(B1-22)R, reduced in a dose-dependent manner the volume of 0.3 m NaCl solution consumed when offered to sodium-depleted C57Bl/6J wild-type mice, relative to vehicle-treated control animals. Notably, i.c.v. R3(B1-22)R infusion did not alter 0.3 m NaCl consumption relative to vehicle in sodium-depleted Rxfp3 knockout mice, confirming the pharmacological specificity of this effect. Furthermore, i.c.v. R3(B1-22)R did not alter the volume of water consumed by wild-type mice in three tests where water drinking was the normal physiological response, suggesting that the ability of R3(B1-22)R to reduce activated salt appetite is specific and not due to a generalized reduction in drinking behaviour. These findings identify, for the first time, that endogenous relaxin-3-RXFP3 signalling is a powerful mediator of salt appetite in mice and further elucidate the functional role of the relaxin-3-RXFP3 system in the integrative control of motivated behaviours.