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1.
Lancet Respir Med ; 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38851197

RESUMEN

BACKGROUND: Long-term effects of early, recurrent human exposure to general anaesthesia remain unknown. The Australasian Cystic Fibrosis Bronchoalveolar Lavage (ACFBAL) trial provided an opportunity to examine this issue in children randomly assigned in infancy to either repeated bronchoalveolar-lavage (BAL)-directed therapy with general anaesthesia or standard care with no planned lavages up to 5 years of age when all children received BAL-directed therapy under general anaesthesia. METHODS: This multicentre, randomised, open-label phase 4 trial (CF-GAIN) used the original ACFBAL trial randomisation at 3·6 months (SD 1·6) to BAL-directed therapy or standard-care groups to assess the impact of general anaesthesia exposures over early childhood. Children who completed the ACFBAL trial, with a mean age of 5·1 (SD 0·18) years, received standardised neurobehavioural and health-related-quality-of-life assessment and brain MRI scans between Oct 8, 2013, and June 30, 2017, at a mean age of 12·8 (SD 1·7) years at three hospitals in Australia and one hospital in New Zealand. The primary outcome was a composite score of performance on a standardised, computer-based assessment of child attention, processing speed, and response inhibition skills (Conners Continuous Performance test, second edition). Secondary outcomes included intellectual function, other neurobehavioural measures, and brain imaging as an exploratory outcome. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN 12613000057785) and is completed. FINDINGS: At 2 years, the BAL-directed therapy group (n=52) and standard-care group (n=45) had a median of 2·0 (IQR 1·0-3·0) and 0·0 (0·0-0·0) exposures, respectively. At completion of the ACFBAL trial, the BAL-directed therapy group had a median of 6·0 (4·0-9·5) exposures and the standard-care group 2·0 (1·0-4·0) exposures. At CF-GAIN completion, the BAL-directed therapy group had a median of 10·0 (IQR 6·5-14·5) exposures and the standard-care group 4·0 (3·0-7·0) exposures. Cumulative general anaesthesia exposure time was not prospectively collected but, for those with complete cumulative exposure time data to the end of the ACFBAL trial, the median cumulative exposure time for the BAL-directed therapy group (n=29) was 180 (IQR 140-285) min and for the standard-care group (n=32) was 48 (30-122) min. The mean Conners Continuous Performance test, second edition composite score was 51 (SD 8·1) in BAL-directed therapy group and 53 (8·8) in the standard-care group; difference -1·7 (95% CI -5·2 to 1·7; p=0·32) with similar performance on other neurobehavioural measures, including measures of executive function, intellectual quotient scores, and brain imaging. INTERPRETATION: Our findings suggest that repeated general anaesthesia exposure in young children with cystic fibrosis is not related to functional impairment in attention, intellectual quotient, executive function, or brain structure compared with a group with fewer and shorter cumulative anaesthesia durations. FUNDING: National Health and Medical Research Council Australia, Queensland Government Health Service and Clinical Innovation Fellowship, and the Children's Hospital Foundation Queensland.

2.
Learn Mem ; 31(5)2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38862171

RESUMEN

Across animal species, dopamine-operated memory systems comprise anatomically segregated, functionally diverse subsystems. Although individual subsystems could operate independently to support distinct types of memory, the logical interplay between subsystems is expected to enable more complex memory processing by allowing existing memory to influence future learning. Recent comprehensive ultrastructural analysis of the Drosophila mushroom body revealed intricate networks interconnecting the dopamine subsystems-the mushroom body compartments. Here, we review the functions of some of these connections that are beginning to be understood. Memory consolidation is mediated by two different forms of network: A recurrent feedback loop within a compartment maintains sustained dopamine activity required for consolidation, whereas feed-forward connections across compartments allow short-term memory formation in one compartment to open the gate for long-term memory formation in another compartment. Extinction and reversal of aversive memory rely on a similar feed-forward circuit motif that signals omission of punishment as a reward, which triggers plasticity that counteracts the original aversive memory trace. Finally, indirect feed-forward connections from a long-term memory compartment to short-term memory compartments mediate higher-order conditioning. Collectively, these emerging studies indicate that feedback control and hierarchical connectivity allow the dopamine subsystems to work cooperatively to support diverse and complex forms of learning.


Asunto(s)
Dopamina , Cuerpos Pedunculados , Animales , Dopamina/metabolismo , Dopamina/fisiología , Cuerpos Pedunculados/fisiología , Cuerpos Pedunculados/metabolismo , Drosophila/fisiología , Retroalimentación Fisiológica/fisiología , Consolidación de la Memoria/fisiología , Red Nerviosa/fisiología , Red Nerviosa/metabolismo , Neuronas Dopaminérgicas/fisiología , Neuronas Dopaminérgicas/metabolismo , Vías Nerviosas/fisiología
4.
Paediatr Anaesth ; 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38738779

RESUMEN

Two prior reviews highlight the scarcity and conflicting nature of available data on chronic postsurgical pain in children, reporting a wide prevalence range of 3.2% to 64% (at ≥3 months). This updated systematic review aimed to consolidate information on the prevalence of pediatric chronic postsurgical pain. A thorough literature search of full English-text publications from April 2014 to August 2021 was conducted using Ovid MEDLINE, PubMed, and Cochrane Database of Systematic Reviews, with search terms: postoperative pain, child, preschool, pediatrics, adolescent, chronic pain. Seventeen relevant studies were identified. Most assessed chronicity once greater than 3 months duration postoperatively (82%), were predominantly prospective (71%) and conducted in inpatient settings (88%). The surgeries examined included orthopedic (scoliosis and limb), urological, laparotomy, inguinal, and cardiothoracic procedures, involving numbers ranging from 36 to 750, totaling 3137 participants/2792 completers. The studies had wide variations in median age at surgery (6 days to 16 years), the percentage of female participants (unspecified or 12.5% to 90%), and follow-up duration (2.5 months to 9 years). Various pain, functional, psychosocial, and health-related quality of life outcomes were documented. Chronic postsurgical pain prevalence varied widely from 2% to 100%. Despite increased data, challenges persist due to heterogeneity in definitions, patient demographics, mixed versus single surgical populations, diverse perioperative analgesic interventions, follow-up durations and reported outcomes. Interpretation is further complicated by limited information on impact, long-term analgesia and healthcare utilization, and relatively small sample sizes, hindering the assessment of reported associations. In some cases, preoperative pain and deformity may not have been addressed by surgery and persisting pain postoperatively may then be inappropriately termed chronic postsurgical pain. Larger-scale, procedure-specific data to better assess current prevalence, impact, and whether modifiable factors link to negative long-term outcomes, would be more useful and allow targeted perioperative interventions for at-risk pediatric surgical patients.

5.
Lancet Respir Med ; 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38788748

RESUMEN

BACKGROUND: Tubeless upper airway surgery in children is a complex procedure in which surgeons and anaesthetists share the same operating field. These procedures are often interrupted for rescue oxygen therapy. The efficacy of nasal high-flow oxygen to decrease the frequency of rescue interruptions in children undergoing upper airway surgery is unknown. METHODS: In this multicentre randomised trial conducted in five tertiary hospitals in Australia, children aged 0-16 years who required tubeless upper airway surgery were randomised (1:1) by a web-based randomisation tool to either nasal high-flow oxygen delivery or standard oxygen therapy (oxygen flows of up to 6 L/min). Randomisation was stratified by site and age (<1 year, 1-4 years, and 5-16 years). Subsequent tubeless upper airway surgery procedures in the same child could be included if there were more than 2 weeks between the procedures, and repeat surgical procedures meeting this condition were considered to be independent events. The oxygen therapy could not be masked, but the investigators remained blinded until outcome data were locked. The primary outcome was successful anaesthesia without interruption of the surgical procedure for rescue oxygenation. A rescue oxygenation event was defined as an interruption of the surgical procedure to deliver positive pressure ventilation using either bag mask technique, insertion of an endotracheal tube, or laryngeal mask to improve oxygenation. There were ten secondary outcomes, including the proportion of procedures with a hypoxaemic event (SpO2 <90%). Analyses were done on an intention-to-treat (ITT) basis. Safety was assessed in all enrolled participants. This trial is registered in the Australian New Zealand Clinical Trials Registry, ACTRN12618000949280, and is completed. FINDINGS: From Sept 4, 2018, to April 12, 2021, 581 procedures in 487 children were randomly assigned to high-flow oxygen (297 procedures) or standard care (284 procedures); after exclusions, 528 procedures (267 assigned to high-flow oxygen and 261 assigned to standard care) in 483 children (293 male and 190 female) were included in the ITT analysis. The primary outcome of successful anaesthesia without interruption for tubeless airway surgery was achieved in 236 (88%) of 267 procedures on high-flow oxygen and in 229 (88%) of 261 procedures on standard care (adjusted risk ratio [RR] 1·02, 95% CI 0·96-1·08, p=0·82). There were 51 (19%) procedures with a hypoxaemic event in the high-flow oxygen group and 57 (22%) in the standard care group (RR 0·86, 95% CI 0·58-1·24). Of the other prespecified secondary outcomes, none showed a significant difference between groups. Adverse events of epistaxis, laryngospasm, bronchospasm, hypoxaemia, bradycardia, cardiac arrest, hypotension, or death were similar in both study groups. INTERPRETATION: Nasal high-flow oxygen during tubeless upper airway surgery did not reduce the proportion of interruptions of the procedures for rescue oxygenation compared with standard care. There were no differences in adverse events between the intervention groups. These results suggest that both approaches, nasal high-flow or standard oxygen, are suitable alternatives to maintain oxygenation in children undergoing upper airway surgery. FUNDING: Thrasher Research Fund, the Australian and New Zealand College of Anaesthetists, the Society for Paediatric Anaesthesia in New Zealand and Australia.

6.
J Neurol Surg B Skull Base ; 85(3): 247-254, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38721359

RESUMEN

Objectives Sellar pathologies are frequently found on imaging performed to investigate headache. However, both headache and incidental sellar lesions are common. Hence, this study prospectively examined headache prevalence, phenotype, and severity in patients with sellar pathologies and the impact of transsphenoidal surgery on headache. Methods Patients undergoing transsphenoidal resection of sellar lesions were consecutively recruited. At baseline, participants were defined as having headache or not and headache phenotype was characterized using validated questionnaires. Headache severity was assessed at baseline and 6 months postoperatively using the Headache Impact Test-6 (HIT-6) and Migraine Disability Assessment Score (MIDAS). Tumor characteristics were defined using radiological, histological, and endocrine factors. Primary outcomes included baseline headache prevalence and severity and headache severity change at 6 months postoperatively. Correlation between headache and radiological, histological, and endocrine characteristics was also of interest. Results Sixty participants (62% female, 47.1 ± 18.6 years) were recruited. Sixty-three percent possessed baseline headache. HIT-6 scores were higher in patients with primary headache risk factors, including younger age (R 2 = -0.417, p = 0.010), smoking history (63.31 ± 7.93 vs 54.44 ± 9.21, p = 0.0060), and family headache history (68.13 ± 7.01 vs 54.94 ± 9.11, p = 0.0030). Headaches were more common in patients with dural invasion (55.70 ± 12.14 vs 47.18 ± 10.15, p = 0.027) and sphenoid sinus invasion (58.87 ± 8.97 vs 51.29 ± 10.97, p = 0.007). Postoperative severity scores improved more with higher baseline headache severity (HIT-6: R 2 = -0.682, p < 0.001, MIDAS: R 2 = -0.880, p < 0.0010) and dural invasion (MIDAS: -53.00 ± 18.68 vs 12.00 ± 17.54, p = 0.0030). Conclusion Headaches in sellar disease are likely primary disorders triggered or exacerbated by sellar pathology. These may respond to surgery, particularly in patients with severe headache and dural invasion.

7.
Anesthesiology ; 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38775960

RESUMEN

While effects of general anesthesia on neuronal activity in the human neonatal brain are incompletely understood, electroencephalography (EEG) provides some insight and may identify age-dependent differences. A systematic search (MEDLINE, Embase, PUBMED, Cochrane Library to November 2023) retrieved English language publications reporting EEG during general anesthesia for cardiac or non-cardiac surgery in term neonates (37 to 44 weeks post-menstrual age). Data were extracted and risk of bias (ROBINS-I Cochrane tool) and quality of evidence (GRADE checklist) assessed. From 1155 abstracts, nine publications (157 neonates; 55.7% male) fulfilled eligibility criteria. Data were limited and study quality was very low. The occurrence of discontinuity, a characteristic pattern of alternating higher and lower amplitude EEG segments, was reported with general anesthesia (94 of 119 neonates, six publications) and with hypothermia (23 of 23 neonates, two publications). Decreased power in the delta (0.5-4Hz) frequency range was also reported with increasing anesthetic dose (39 neonates; three publications). While evidence gaps were identified, both increasing sevoflurane concentration and decreasing temperature are associated with increasing discontinuity.

8.
EClinicalMedicine ; 72: 102616, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38774675

RESUMEN

Background: Bacille Calmette-Guérin (BCG) vaccination has off-target (non-specific) effects that are associated with protection against unrelated infections and decreased all-cause mortality in infants. We aimed to determine whether BCG vaccination prevents febrile and respiratory infections in adults. Methods: This randomised controlled phase 3 trial was done in 36 healthcare centres in Australia, Brazil, the Netherlands, Spain, and the United Kingdom. Healthcare workers were randomised to receive BCG-Denmark (single 0.1 ml intradermal injection) or no BCG in a 1:1 ratio using a web-based procedure, stratified by stage, site, age, and presence of co-morbidity. The difference in occurrence of febrile or respiratory illness were measured over 12 months (prespecified secondary outcome) using the intention-to-treat (ITT) population. This trial is registered with ClinicalTrials.gov, NCT04327206. Findings: Between March 30, 2020, and April 1, 2021, 6828 healthcare workers were randomised to BCG-Denmark (n = 3417) or control (n = 3411; no intervention or placebo) groups. The 12-month adjusted estimated risk of ≥1 episode of febrile or respiratory illness was 66.8% in the BCG group (95% CI 65.3%-68.2%), compared with 63.4% in the control group (95% CI 61.8%-65.0%), a difference of +3.4 percentage points (95% CI +1.3% to +5.5%; p 0.002). The adjusted estimated risk of a severe episode (defined as being incapacitated for ≥3 consecutive days or hospitalised) was 19.4% in the BCG group (95% CI 18.0%-20.7%), compared with 18.8% in the control group (95% CI 17.4%-20.2%) a difference of +0.6 percentage points (95% CI -1.3% to +2.5%; p 0.6). Both groups had a similar number of episodes of illness, pneumonia, and hospitalisation. There were three deaths, all in the control group. There were no safety concerns following BCG vaccination. Interpretation: In contrast to the beneficial off-target effects reported following neonatal BCG in infants, a small increased risk of symptomatic febrile or respiratory illness was observed in the 12 months following BCG vaccination in adults. There was no evidence of a difference in the risk of severe disease. Funding: Bill & Melinda Gates Foundation, Minderoo Foundation, Sarah and Lachlan Murdoch, the Royal Children's Hospital Foundation, Health Services Union NSW, the Peter Sowerby Foundation, SA Health, the Insurance Advisernet Foundation, the NAB Foundation, the Calvert-Jones Foundation, the Modara Pines Charitable Foundation, the UHG Foundation Pty Ltd, Epworth Healthcare, the National Health and Medical Research Council, the Swiss National Science Foundation and individual donors.

9.
Methods Cell Biol ; 187: 99-116, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38705632

RESUMEN

Correlative Light Electron Microscopy (CLEM) is a powerful technique to investigate the ultrastructure of specific cells and organelles at sub-cellular resolution. Transmission Electron Microscopy (TEM) is particularly useful to the field of virology, given the small size of the virion, which is below the limit of detection by light microscopy. Furthermore, viral infection results in the rearrangement of host organelles to form spatially defined compartments that facilitate the replication of viruses. With the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there has been great interest to study the viral replication complex using CLEM. In this chapter we provide an exemplary workflow describing the safe preparation and processing of cells grown on coverslips and infected with SARS-CoV-2.


Asunto(s)
COVID-19 , SARS-CoV-2 , SARS-CoV-2/ultraestructura , Humanos , COVID-19/virología , Células Vero , Chlorocebus aethiops , Animales , Microscopía Electrónica de Transmisión/métodos , Replicación Viral , Microscopía Electrónica/métodos
10.
Emerg Med Australas ; 36(3): 488-490, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38600436

RESUMEN

Adaptive platform trials (APTs) offer a promising alternative to traditional randomised controlled trials for evaluating treatments for paediatric sepsis. Randomised controlled trials, despite being the gold standard for establishing causality between interventions and outcomes, make many assumptions about disease prevalence, severity and intervention effects, which are often incorrect. As a result, the evidence for most treatments for paediatric sepsis are based on low-quality evidence. APTs use accrued data rather than assumptions to power trial adaptations. They can assess multiple treatments simultaneously with shared research infrastructure. As such, APTs offer a more efficient, flexible and more effective way to identify optimal treatments. The proposed Paediatric Adaptive Sepsis Platform Trial, leveraging the Paediatric Research in Emergency Departments International Collaborative network's infrastructure, will evaluate resuscitation fluids, vasoactive medications, corticosteroids and antimicrobials. This trial has the potential to substantially impact clinical practice and reduce global sepsis mortality in children.


Asunto(s)
Ensayos Clínicos Controlados Aleatorios como Asunto , Sepsis , Humanos , Sepsis/terapia , Sepsis/tratamiento farmacológico , Niño , Pediatría/métodos , Proyectos de Investigación
11.
J Am Chem Soc ; 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38592946

RESUMEN

Selectively labeling cells with damaged membranes is needed not only for identifying dead cells in culture, but also for imaging membrane barrier dysfunction in pathologies in vivo. Most membrane permeability stains are permanently colored or fluorescent dyes that need washing to remove their non-uptaken extracellular background and reach good image contrast. Others are DNA-binding environment-dependent fluorophores, which lack design modularity, have potential toxicity, and can only detect permeabilization of cell volumes containing a nucleus (i.e., cannot delineate damaged volumes in vivo nor image non-nucleated cell types or compartments). Here, we develop modular fluorogenic probes that reveal the whole cytosolic volume of damaged cells, with near-zero background fluorescence so that no washing is needed. We identify a specific disulfonated fluorogenic probe type that only enters cells with damaged membranes, then is enzymatically activated and marks them. The esterase probe MDG1 is a reliable tool to reveal live cells that have been permeabilized by biological, biochemical, or physical membrane damage, and it can be used in multicolor microscopy. We confirm the modularity of this approach by also adapting it for improved hydrolytic stability, as the redox probe MDG2. We conclude by showing the unique performance of MDG probes in revealing axonal membrane damage (which DNA fluorogens cannot achieve) and in discriminating damage on a cell-by-cell basis in embryos in vivo. The MDG design thus provides powerful modular tools for wash-free in vivo imaging of membrane damage, and indicates how designs may be adapted for selective delivery of drug cargoes to these damaged cells: offering an outlook from selective diagnosis toward therapy of membrane-compromised cells in disease.

12.
Nat Commun ; 15(1): 3487, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38664424

RESUMEN

An improved understanding of the underlying physicochemical properties of respiratory aerosol that influence viral infectivity may open new avenues to mitigate the transmission of respiratory diseases such as COVID-19. Previous studies have shown that an increase in the pH of respiratory aerosols following generation due to changes in the gas-particle partitioning of pH buffering bicarbonate ions and carbon dioxide is a significant factor in reducing SARS-CoV-2 infectivity. We show here that a significant increase in SARS-CoV-2 aerostability results from a moderate increase in the atmospheric carbon dioxide concentration (e.g. 800 ppm), an effect that is more marked than that observed for changes in relative humidity. We model the likelihood of COVID-19 transmission on the ambient concentration of CO2, concluding that even this moderate increase in CO2 concentration results in a significant increase in overall risk. These observations confirm the critical importance of ventilation and maintaining low CO2 concentrations in indoor environments for mitigating disease transmission. Moreover, the correlation of increased CO2 concentration with viral aerostability need to be better understood when considering the consequences of increases in ambient CO2 levels in our atmosphere.


Asunto(s)
COVID-19 , Dióxido de Carbono , SARS-CoV-2 , Dióxido de Carbono/metabolismo , Dióxido de Carbono/análisis , COVID-19/transmisión , COVID-19/virología , Humanos , Concentración de Iones de Hidrógeno , Aerosoles , Humedad , Ventilación , Aerosoles y Gotitas Respiratorias/metabolismo , Aerosoles y Gotitas Respiratorias/virología , Atmósfera/química
13.
BMC Med Educ ; 24(1): 418, 2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38637798

RESUMEN

BACKGROUND: In the past, evidence-based medicine (EBM) and shared decision-making (SDM) have been taught separately in health sciences and medical education. However, recognition is increasing of the importance of EBM training that includes SDM, whereby practitioners incorporate all steps of EBM, including person-centered decision-making using SDM. However, there are few empirical investigations into the benefits of training that integrates EBM and SDM (EBM-SDM) for junior doctors, and their influencing factors. This study aimed to explore how integrated EBM-SDM training can influence junior doctors' attitudes to and practice of EBM and SDM; to identify the barriers and facilitators associated with junior doctors' EBM-SDM learning and practice; and to examine how supervising consultants' attitudes and authority impact on junior doctors' opportunities for EBM-SDM learning and practice. METHODS: We developed and ran a series of EBM-SDM courses for junior doctors within a private healthcare setting with protected time for educational activities. Using an emergent qualitative design, we first conducted pre- and post-course semi-structured interviews with 12 junior doctors and thematically analysed the influence of an EBM-SDM course on their attitudes and practice of both EBM and SDM, and the barriers and facilitators to the integrated learning and practice of EBM and SDM. Based on the responses of junior doctors, we then conducted interviews with ten of their supervising consultants and used a second thematic analysis to understand the influence of consultants on junior doctors' EBM-SDM learning and practice. RESULTS: Junior doctors appreciated EBM-SDM training that involved patient participation. After the training course, they intended to improve their skills in person-centered decision-making including SDM. However, junior doctors identified medical hierarchy, time factors, and lack of prior training as barriers to the learning and practice of EBM-SDM, whilst the private healthcare setting with protected learning time and supportive consultants were considered facilitators. Consultants had mixed attitudes towards EBM and SDM and varied perceptions of the role of junior doctors in either practice, both of which influenced the practice of junior doctors. CONCLUSIONS: These findings suggested that future medical education and research should include training that integrates EBM and SDM that acknowledges the complex environment in which this training must be put into practice, and considers strategies to overcome barriers to the implementation of EBM-SDM learning in practice.


Asunto(s)
Consultores , Medicina Basada en la Evidencia , Humanos , Medicina Basada en la Evidencia/educación , Investigación Cualitativa , Actitud del Personal de Salud , Cuerpo Médico de Hospitales , Toma de Decisiones
14.
J Physiol ; 602(9): 2019-2045, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38488688

RESUMEN

Activation of the cAMP pathway is one of the common mechanisms underlying long-term potentiation (LTP). In the Drosophila mushroom body, simultaneous activation of odour-coding Kenyon cells (KCs) and reinforcement-coding dopaminergic neurons activates adenylyl cyclase in KC presynaptic terminals, which is believed to trigger synaptic plasticity underlying olfactory associative learning. However, learning induces long-term depression (LTD) at these synapses, contradicting the universal role of cAMP as a facilitator of transmission. Here, we developed a system to electrophysiologically monitor both short-term and long-term synaptic plasticity at KC output synapses and demonstrated that they are indeed an exception in which activation of the cAMP-protein kinase A pathway induces LTD. Contrary to the prevailing model, our cAMP imaging found no evidence for synergistic action of dopamine and KC activity on cAMP synthesis. Furthermore, we found that forskolin-induced cAMP increase alone was insufficient for plasticity induction; it additionally required simultaneous KC activation to replicate the presynaptic LTD induced by pairing with dopamine. On the other hand, activation of the cGMP pathway paired with KC activation induced slowly developing LTP, proving antagonistic actions of the two second-messenger pathways predicted by behavioural study. Finally, KC subtype-specific interrogation of synapses revealed that different KC subtypes exhibit distinct plasticity duration even among synapses on the same postsynaptic neuron. Thus, our work not only revises the role of cAMP in synaptic plasticity by uncovering the unexpected convergence point of the cAMP pathway and neuronal activity, but also establishes the methods to address physiological mechanisms of synaptic plasticity in this important model. KEY POINTS: Although presynaptic cAMP increase generally facilitates synapses, olfactory associative learning in Drosophila, which depends on dopamine and cAMP signalling genes, induces long-term depression (LTD) at the mushroom body output synapses. By combining electrophysiology, pharmacology and optogenetics, we directly demonstrate that these synapses are an exception where activation of the cAMP-protein kinase A pathway leads to presynaptic LTD. Dopamine- or forskolin-induced cAMP increase alone is not sufficient for LTD induction; neuronal activity, which has been believed to trigger cAMP synthesis in synergy with dopamine input, is required in the downstream pathway of cAMP. In contrast to cAMP, activation of the cGMP pathway paired with neuronal activity induces presynaptic long-term potentiation, which explains behaviourally observed opposing actions of transmitters co-released by dopaminergic neurons. Our work not only revises the role of cAMP in synaptic plasticity, but also provides essential methods to address physiological mechanisms of synaptic plasticity in this important model system.


Asunto(s)
AMP Cíclico , Cuerpos Pedunculados , Plasticidad Neuronal , Animales , Cuerpos Pedunculados/fisiología , AMP Cíclico/metabolismo , Plasticidad Neuronal/fisiología , Dopamina , Potenciación a Largo Plazo/fisiología , Drosophila melanogaster/fisiología , GMP Cíclico/metabolismo , Sinapsis/fisiología , Depresión Sináptica a Largo Plazo/fisiología , Colforsina/farmacología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo
16.
J Clin Neurosci ; 121: 67-74, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38364728

RESUMEN

OBJECTIVE: Decompressive craniectomy (DC) remains a controversial intervention for intracranial hypertension among patients with aneurysmal subarachnoid haemorrhage (aSAH). METHODS: We identified aSAH patients who underwent DC following microsurgical aneurysm repair from a prospectively maintained registry and compared their outcomes with a propensity-matched cohort who did not. Logistic regression was used to identify predictors of undergoing decompressive surgery and post-operative outcome. Outcomes of interest were inpatient mortality, unfavourable outcome, NIS-Subarachnoid Hemorrhage Outcome Measure and modified Rankin Score (mRS). RESULTS: A total of 246 patients with aSAH underwent clipping of the culprit aneurysm between 01/09/2011 and 20/07/2020. Of these, 46 underwent DC and were included in the final analysis. Unsurprisingly, DC patients had a greater chance of unfavourable outcome (p < 0.001) and higher median mRS (p < 0.001) at final follow-up. Despite this, almost two-thirds (64.1 %) of DC patients had a favourable outcome at this time-point. When compared with a propensity-matched cohort who did not, patients treated with DC fared worse at all endpoints. Multivariable logistic regression revealed that the presence of intracerebral haemorrhage and increased pre-operative mid-line shift were predictive of undergoing DC, and WFNS grade ≥ 4 and a delayed ischaemic neurological deficit requiring endovascular angioplasty were associated with an unfavourable outcome. CONCLUSIONS: Our data suggest that DC can be performed with acceptable rates of morbidity and mortality. Further research is required to determine the superiority, or otherwise, of DC compared with structured medical management of intracranial hypertension in this context, and to identify predictors of requiring decompressive surgery and patient outcome.


Asunto(s)
Aneurisma Roto , Craniectomía Descompresiva , Aneurisma Intracraneal , Hipertensión Intracraneal , Hemorragia Subaracnoidea , Humanos , Resultado del Tratamiento , Craniectomía Descompresiva/efectos adversos , Australia del Sur , Australia , Hemorragia Subaracnoidea/cirugía , Hipertensión Intracraneal/cirugía , Aneurisma Roto/cirugía , Sistema de Registros , Aneurisma Intracraneal/complicaciones , Aneurisma Intracraneal/cirugía
17.
Antiviral Res ; 224: 105837, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38387750

RESUMEN

The COVID-19 pandemic has shown the need to develop effective therapeutics in preparedness for further epidemics of virus infections that pose a significant threat to human health. As a natural compound antiviral candidate, we focused on α-dystroglycan, a highly glycosylated basement membrane protein that links the extracellular matrix to the intracellular cytoskeleton. Here we show that the N-terminal fragment of α-dystroglycan (α-DGN), as produced in E. coli in the absence of post-translational modifications, blocks infection of SARS-CoV-2 in cell culture, human primary gut organoids and the lungs of transgenic mice expressing the human receptor angiotensin I-converting enzyme 2 (hACE2). Prophylactic and therapeutic administration of α-DGN reduced SARS-CoV-2 lung titres and protected the mice from respiratory symptoms and death. Recombinant α-DGN also blocked infection of a wide range of enveloped viruses including the four Dengue virus serotypes, influenza A virus, respiratory syncytial virus, tick-borne encephalitis virus, but not human adenovirus, a non-enveloped virus in vitro. This study establishes soluble recombinant α-DGN as a broad-band, natural compound candidate therapeutic against enveloped viruses.


Asunto(s)
COVID-19 , SARS-CoV-2 , Ratones , Animales , Humanos , Distroglicanos , Pandemias , Escherichia coli , Ratones Transgénicos , Antivirales/farmacología
18.
Anesthesiology ; 140(5): 890-905, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38207324

RESUMEN

BACKGROUND: High-density electroencephalographic (EEG) monitoring remains underutilized in clinical anesthesia, despite its obvious utility in unraveling the profound physiologic impact of these agents on central nervous system functioning. In school-aged children, the routine practice of rapid induction with high concentrations of inspiratory sevoflurane is commonplace, given its favorable efficacy and tolerance profile. However, few studies investigate topographic EEG during the critical timepoint coinciding with loss of responsiveness-a key moment for anesthesiologists in their everyday practice. The authors hypothesized that high initial sevoflurane inhalation would better precipitate changes in brain regions due to inhomogeneities in maturation across three different age groups compared with gradual stepwise paradigms utilized by other investigators. Knowledge of these changes may inform strategies for agent titration in everyday clinical settings. METHODS: A total of 37 healthy children aged 5 to 10 yr underwent induction with 4% or greater sevoflurane in high-flow oxygen. Perturbations in anesthetic state were investigated in 23 of these children using 64-channel EEG with the Hjorth Laplacian referencing scheme. Topographical maps illustrated absolute, relative, and total band power across three age groups: 5 to 6 yr (n = 7), 7 to 8 yr (n = 8), and 9 to 10 yr (n = 8). RESULTS: Spectral analysis revealed a large shift in total power driven by increased delta oscillations. Well-described topographic patterns of anesthesia, e.g., frontal predominance, paradoxical beta excitation, and increased slow activity, were evident in the topographic maps. However, there were no statistically significant age-related changes in spectral power observed in a midline electrode subset between the groups when responsiveness was lost compared to the resting state. CONCLUSIONS: High initial concentration sevoflurane induction causes large-scale topographic effects on the pediatric EEG. Within the minute after unresponsiveness, this dosage may perturb EEG activity in children to an extent where age-related differences are not discernible.


Asunto(s)
Anestésicos por Inhalación , Éteres Metílicos , Niño , Humanos , Preescolar , Sevoflurano , Anestésicos por Inhalación/farmacología , Electroencefalografía , Anestesia General , Encéfalo
19.
Arch Dis Child ; 109(3): 227-232, 2024 02 19.
Artículo en Inglés | MEDLINE | ID: mdl-38049992

RESUMEN

OBJECTIVE: To describe the prevalence and severity of pain experienced by children with Bell's palsy over the first 6 months of illness and its association with the severity of facial paralysis. METHODS: This was a secondary analysis of data obtained in a phase III, triple-blinded, randomised, placebo-controlled trial of prednisolone for the treatment of Bell's palsy in children aged 6 months to <18 years conducted between 13 October 2015 and 23 August 2020 in Australia and New Zealand. Children were recruited within 72 hours of symptom onset and pain was assessed using a child-rated visual analogue scale (VAS), a child-rated Faces Pain Score-Revised (FPS-R) and/or a parent-rated VAS at baseline, and at 1, 3 and 6 months until recovered, and are reported combined across treatment groups. RESULTS: Data were available for 169 of the 187 children randomised from at least one study time point. Overall, 37% (62/169) of children reported any pain at least at one time point. The frequency of any pain reported using the child-rated VAS, child-rated FPS-R and parent-rated VAS was higher at the baseline assessment (30%, 23% and 27%, respectively) compared with 1-month (4%, 0% and 4%, respectively) and subsequent follow-up assessments. At all time points, the median pain score on all three scales was 0 (no pain). CONCLUSIONS: Pain in children with Bell's palsy was infrequent and primarily occurred early in the disease course and in more severe disease. The intensity of pain, if it occurs, is very low throughout the clinical course of disease. TRIAL REGISTRATION NUMBER: ACTRN12615000563561.


Asunto(s)
Parálisis de Bell , Parálisis Facial , Dolor , Humanos , Parálisis de Bell/complicaciones , Parálisis de Bell/tratamiento farmacológico , Parálisis de Bell/epidemiología , Parálisis Facial/tratamiento farmacológico , Dolor/tratamiento farmacológico , Dolor/epidemiología , Dolor/etiología , Prednisolona/uso terapéutico , Ensayos Clínicos Fase III como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Lactante , Preescolar , Niño , Adolescente
20.
Ecology ; 105(1): e4213, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38029361

RESUMEN

Warming has broad and often nonlinear impacts on organismal physiology and traits, allowing it to impact species interactions like predation through a variety of pathways that may be difficult to predict. Predictions are commonly based on short-term experiments and models, and these studies often yield conflicting results depending on the environmental context, spatiotemporal scale, and the predator and prey species considered. Thus, the accuracy of predicted changes in interaction strength, and their importance to the broader ecosystems they take place in, remain unclear. Here, we attempted to link one such set of predictions generated using theory, modeling, and controlled experiments to patterns in the natural abundance of prey across a broad thermal gradient. To do so, we first predicted how warming would impact a stage-structured predator-prey interaction in riverine rock pools between Pantala spp. dragonfly nymph predators and Aedes atropalpus mosquito larval prey. We then described temperature variation across a set of hundreds of riverine rock pools (n = 775) and leveraged this natural gradient to look for evidence for or against our model's predictions. Our model's predictions suggested that warming should weaken predator control of mosquito larval prey by accelerating their development and shrinking the window of time during which aquatic dragonfly nymphs could consume them. This was consistent with data collected in rock pool ecosystems, where the negative effects of dragonfly nymph predators on mosquito larval abundance were weaker in warmer pools. Our findings provide additional evidence to substantiate our model-derived predictions while emphasizing the importance of assessing similar predictions using natural gradients of temperature whenever possible.


Asunto(s)
Aedes , Odonata , Animales , Ecosistema , Odonata/fisiología , Larva/fisiología , Conducta Predatoria/fisiología , Cadena Alimentaria
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