8 research outputs found

    Effects of a Synthetic Cannabinoid on the Reinforcing Efficacy of Ethanol in Rats

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    The co-abuse of alcohol and marijuana is widespread, although the mechanisms underlying this behavior are unclear. There is some evidence of a relationship between the neural processes that mediate the effects of ethanol and marijuana. For example, research has shown that exposure to marijuana increases responding for, and intake of, ethanol. The alcohol deprivation effect is an anima l model of alcoholism that suggests that the reinforcing efficacy of ethanol, as measured by intake, increases following a period of deprivation. Recent research indicates that rats chronically exposed to marijuana during periods of alcohol deprivation consume ethanol above and beyond deprivation alone. It is unclear, however, whether the marijuana exposure or the repeated deprivations increased motivation to consume ethanol. In the present experiment, rats were trained to self-administer ethanol on a progressive ratio schedule and subjected to two separate periods of deprivation during which either drug or saline was chronically administered for 7 days. Breakpoint (i.e., last ratio completed) was recorded as a measure of the reinforcing efficacy of ethanol. Following deprivations, breakpoint was initially lower than baseline, regardless of whether the drug or saline was administered. Breakpoint recovered to, but did not exceed, baseline levels following both deprivations, indicating a lack of increased reinforcing efficacy of ethanol after repeated deprivation or chronic exposure to marijuana. The lack of an expression of an alcohol deprivation effect following deprivation may have been due to the length and number of deprivations employed. Furthermore, lowered breakpoint recorded following chronic drug administration during deprivation may have been due to the dose administered or stress generated by chronic injections . Further investigation is necessary to separate and clarify the variables responsible for the present results

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Discriminative Control of Variability: Effects of Successive Stimulus Reversals

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    A growing body of evidence suggests that behavioral variability can come under control of discriminative stimuli. The present experiment further examined discriminative control of variability in a novel way by using the discrimination-reversal paradigm. Eight pigeons responded under a multiple schedule of Vary and Yoke components signaled by different-colored keylights. In the Vary component, 4-response sequences that differed from the previous 10 produced food, while in the Yoke component, any 4-response sequence had a fixed probability of producing food, yoked to the prior Vary component. Following stability in this procedure, the key colors signaling the Vary and Yoke components were reversed across four successive conditions. Across the experiment, variability of keypeck sequences was higher in the Vary than in the Yoke component. Across successive reversals, the level of variability in the Vary component adapted more rapidly to the reversed contingencies, while the rate of adaptation in the Yoke component did not change systematically. These results are interpreted in terms of the different contingencies in the Vary and Yoke components. In addition, the improvement in the rate of adaptation across successive reversals in the Vary component appears consistent with a proactive interference account of discrimination-reversal performance. These results join others in suggesting that variability may be an operant dimension of behavior

    Brain-Derived Neurotrophic Factor in Pediatric Acquired Brain Injury and Recovery

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    We review emerging preclinical and clinical evidence regarding brain-derived neurotrophic factor (BDNF) protein, genotype, and DNA methylation (DNAm) as biomarkers of outcomes in three important etiologies of pediatric acquired brain injury (ABI), traumatic brain injury, global cerebral ischemia, and stroke. We also summarize evidence suggesting that BDNF is (1) involved in the biological embedding of the psychosocial environment, (2) responsive to rehabilitative therapies, and (3) potentially modifiable. BDNF’s unique potential as a biomarker of neuroplasticity and neural repair that is reflective of and responsive to both pre- and post-injury environmental influences separates it from traditional protein biomarkers of structural brain injury with exciting potential to advance pediatric ABI management by increasing the accuracy of prognostic tools and informing clinical decision making through the monitoring of therapeutic effects

    Effects of D-Amphetamine and Ethanol on Variable and Repetitive Key-Peck Sequences in Pigeons

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    This experiment assessed the effects of d-amphetamine and ethanol on reinforced variable and repetitive key-peck sequences in pigeons. Pigeons responded on two keys under a multiple schedule of Repeat and Vary components. In the Repeat component, completion of a target sequence of right, right, left, left resulted in food. In the Vary component, 4-peck sequences differing from the previous 10 produced food. d-Amphetamine (0.1–3.0 mg/kg, i.m.) was administered in two separate phases, separated by ethanol administration (1.0–2.0 g/kg, i.g.). Under control conditions, measures of variability were high in the Vary component, and lower in the Repeat component. Following administration of the highest dose of d-amphetamine, but not ethanol, response rates decreased in both components. d-Amphetamine and ethanol tended to increase overall sequence variability in the Repeat component, and had less of an effect in the Vary component. Performance in the Repeat component during Phase 2 of d-amphetamine administration was more disrupted than during Phase 1. Measures of variability and repetition based on shifts in the relative frequency distributions of the 16 possible key-peck sequences differed from those based on the overall measure of variability, highlighting the importance of considering both molar and molecular measures when assessing the effects of drugs on reinforced variability and repetition. In addition, the shifts in the relative frequency distribution of response sequences suggest that d-amphetamine produced decrements in repeat performance by decreasing discriminative control within response sequences, whereas ethanol decreased repeat performance by decreasing discriminability between components as well as discriminative control within response sequences
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