Associations of Patient and Parent Characteristics With Parental Decision Regret in the PICU: A Secondary Analysis of the 2015-2017 Navigate Randomized Comparative Trial.

OBJECTIVES: To identify self-reported meaningful decisions made by parents in the PICU and to determine patient and parent characteristics associated with the development of parental decision regret, a measurable, self-reported outcome associated with psychologic morbidity. DESIGN: Secondary analysis of the Navigate randomized comparative trial (NCT02333396). SETTING: Two tertiary, academic PICUs. PATIENTS: Spanish- or English-speaking parents of PICU patients aged less than 18 years who were expected to remain in the PICU for greater than 24 hours from time of enrollment or who had a risk of mortality greater than 4% based on Pediatric Index of Mortality 2 score. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Between April 2015 and March 2017, 233 parents of 209 patients completed a survey 3-5 weeks post-PICU discharge which included the Decision Regret Scale (DRS), a 5-item, 5-point Likert scale tool scored from 0 (no regret) to 100 (maximum regret). Two hundred nine patient/parent dyads were analyzed. The decisions parents reported as most important were categorized as: procedure, respiratory support, medical management, parent-staff interactions and communication, symptom management, fluid/electrolytes/nutrition, and no decision. Fifty-one percent of parents had some decision regret (DRS > 0) with 19% scoring in the moderate-severe range (DRS 26-100). The mean DRS score was 12.7 ( sd 18.1). Multivariable analysis showed that parental Hispanic ethnicity was associated with greater odds ratio (OR 3.12 [95% CI, 1.36-7.13]; p = 0.007) of mild regret. Being parents of a patient with an increased PICU length of stay (LOS) or underlying respiratory disease was associated with greater odds of moderate-severe regret (OR 1.03 [95% CI, 1.009-1.049]; p = 0.004 and OR 2.91 [95% CI, 1.22-6.94]; p = 0.02, respectively). CONCLUSIONS: Decision regret was experienced by half of PICU parents in the 2015-2017 Navigate study. The characteristics associated with decision regret (parental ethnicity, PICU LOS, and respiratory disease) are easily identifiable. Further study is needed to understand what contributes to regret in this population and what interventions could provide support and minimize the development of regret.

Integration of respiratory physiology and clinical reasoning in the early years of a medical curriculum: engaging with students in a large classroom setting.

Medical graduates are expected to apply scientific principles and explain the processes underlying common and important diseases. Evidence shows that integrated medical curricula, which deliver biomedical science within the context of clinical cases, facilitate student learning in preparation for practice. However, research has also shown that the student's perception of their knowledge can be lower in integrated compared to traditional courses. Thus the development of teaching methods to support both integrated learning and build student confidence in clinical reasoning is a priority. In this study, we describe the use of an audience response system to support active learning in large classes. Sessions, delivered by medical faculty from both academic and clinical backgrounds, were designed to build on the knowledge of the respiratory system in both health and disease through the interpretation of clinical cases. Results showed that student engagement was high throughout the session and students strongly agreed that the application of knowledge to real-life cases was a better way to understand clinical reasoning. Qualitative free text comments revealed that students liked the link between theory and practice and the active, integrated method of learning. In summary, this study describes a relatively simple but highly effective way of delivering integrated medical science teaching, in this case respiratory medicine, to improve student confidence in clinical reasoning. This educational approach was applied within the early years of the curriculum in preparation for teaching within a hospital setting, but the format could be applied across many different settings.NEW & NOTEWORTHY The development of teaching methods that support integrated learning and build student confidence is a priority. An audience response system was used to engage early year medical students in large classes in preparation for teaching within a hospital setting. Results showed high levels of student engagement and a greater appreciation for the link between theory and practice. This study describes a simple, active, and integrated method of learning that improves student confidence in clinical reasoning.

Remember to breathe: teaching respiratory physiology in a clinical context using simulation.

Evidence shows that biomedical knowledge is more effectively taught within the medical curriculum by teaching in context, to facilitate learning transfer. The purpose of the present study was to evaluate the effect of combining high-technology simulation and physiology teaching on medical student learning and experience. First-year medical students received respiratory physiology teaching in the form of lectures, problem-based learning, and practical sessions. These students were then given the opportunity to apply their knowledge and problem solve using respiratory-related clinical case scenarios in simulated patients. Student understanding was assessed using a short quiz performed immediately before and after the session. Results revealed that the session significantly improved the mean score on tests (6.97 ± 0.29 vs. 8.22 ± 0.19, P < 0.001). Student evaluation was collected in focus groups, and recurring concepts were extracted from the data. Students reported that the sessions helped to bridge the gap between theory and practice, which aided their learning. In addition, this teaching methodology (simulation) was reportedly patient centered and added to the realism of the simulated scenario, with students stating that this teaching improved their confidence with managing real patients and clinical uncertainty. Simulation has been used extensively to teach clinical skills; however, research regarding its potential for teaching biomedical science within a clinical context is limited. Our study shows that combining high-technology simulation and physiology teaching contributed to an immediate improvement in medical student knowledge and enhanced their ability to make connections between theoretical knowledge and the world of practice.

Communication in pediatric oncology: State of the field and research agenda.

From the time of diagnosis through either survivorship or end of life, communication between healthcare providers and patients or parents can serve several core functions, including fostering healing relationships, exchanging information, responding to emotions, managing uncertainty, making decisions, and enabling patient/family self-management. We systematically reviewed all studies that focused on communication between clinicians and patients or parents in pediatric oncology, categorizing studies based on which core functions of communication they addressed. After identifying gaps in the literature, we propose a research agenda to further the field.

Heat shock induces rapid resorption of primary cilia.

Primary cilia are involved in important developmental and disease pathways, such as the regulation of neurogenesis and tumorigenesis. They function as sensory antennae and are essential in the regulation of key extracellular signalling systems. We have investigated the effects of cell stress on primary cilia. Exposure of mammalian cells in vitro, and zebrafish cells in vivo, to elevated temperature resulted in the rapid loss of cilia by resorption. In mammalian cells loss of cilia correlated with a reduction in hedgehog signalling. Heat-shock-dependent loss of cilia was decreased in cells where histone deacetylases (HDACs) were inhibited, suggesting resorption is mediated by the axoneme-localised tubulin deacetylase HDAC6. In thermotolerant cells the rate of ciliary resorption was reduced. This implies a role for molecular chaperones in the maintenance of primary cilia. The cytosolic chaperone Hsp90 localises to the ciliary axoneme and its inhibition resulted in cilia loss. In the cytoplasm of unstressed cells, Hsp90 is known to exist in a complex with HDAC6. Moreover, immediately after heat shock Hsp90 levels were reduced in the remaining cilia. We hypothesise that ciliary resorption serves to attenuate cilia-mediated signalling pathways in response to extracellular stress, and that this mechanism is regulated in part by HDAC6 and Hsp90.

Role of Active Contraction and Tropomodulins in Regulating Actin Filament Length and Sarcomere Structure in Developing Zebrafish Skeletal Muscle.

Whilst it is recognized that contraction plays an important part in maintaining the structure and function of mature skeletal muscle, its role during development remains undefined. In this study the role of movement in skeletal muscle maturation was investigated in intact zebrafish embryos using a combination of genetic and pharmacological approaches. An immotile mutant line (cacnb1 (ts25) ) which lacks functional voltage-gated calcium channels (dihydropyridine receptors) in the muscle and pharmacological immobilization of embryos with a reversible anesthetic (Tricaine), allowed the study of paralysis (in mutants and anesthetized fish) and recovery of movement (reversal of anesthetic treatment). The effect of paralysis in early embryos (aged between 17 and 24 hours post-fertilization, hpf) on skeletal muscle structure at both myofibrillar and myofilament level was determined using both immunostaining with confocal microscopy and small angle X-ray diffraction. The consequences of paralysis and subsequent recovery on the localization of the actin capping proteins Tropomodulin 1 & 4 (Tmod) in fish aged from 17 hpf until 42 hpf was also assessed. The functional consequences of early paralysis were investigated by examining the mechanical properties of the larval muscle. The length-force relationship, active and passive tension, was measured in immotile, recovered and control skeletal muscle at 5 and 7 day post-fertilization (dpf). Recovery of muscle function was also assessed by examining swimming patterns in recovered and control fish. Inhibition of the initial embryonic movements (up to 24 hpf) resulted in an increase in myofibril length and a decrease in width followed by almost complete recovery in both moving and paralyzed fish by 42 hpf. In conclusion, myofibril organization is regulated by a dual mechanism involving movement-dependent and movement-independent processes. The initial contractile event itself drives the localization of Tmod1 to its sarcomeric position, capping the actin pointed ends and ultimately regulating actin length. This study demonstrates that both contraction and contractile-independent mechanisms are important for the regulation of myofibril organization, which in turn is necessary for establishing proper skeletal muscle structure and function during development in vivo in zebrafish.

Approaches to measuring calcium in zebrafish: focus on neuronal development.

Calcium ions are known to act as important cellular signals during nervous system development. In vitro studies have provided significant information on the role of calcium signals during neuronal development; however, the function of this messenger in nervous system maturation in vivo remains to be established. The zebrafish has emerged as a valuable model for the study of vertebrate embryogenesis. Fertilisation is external and the rapid growth of the transparent embryo, including development of internal organs, can be observed easily making it well suited for imaging studies. The developing nervous system is relatively simple and has been well characterised, allowing individual neurons to be identified. Using the zebrafish model, both intracellular and intercellular calcium signals throughout embryonic development have been characterised. This review summarises technical approaches to measure calcium signals in developing embryonic and larval zebrafish, and includes recent developments that will facilitate the study of calcium signalling in vivo. The application of calcium imaging techniques to investigate the action of this messenger during embryogenesis in intact zebrafish is illustrated by discussion of their contribution to our understanding of neuronal development in vivo.

Spontaneous activity-independent intracellular calcium signals in the developing spinal cord of the zebrafish embryo.

Calcium signals play an important role in a variety of processes necessary for neuronal development. Whilst the characteristics and function of calcium signals have been comprehensively examined in vitro, the significance of these signals during development in an intact embryo remains unclear. In this study, we have examined the spatial and temporal patterns of intracellular calcium signals in precursor cells (cells without processes) within the spinal cord of the intact zebrafish embryo aged between 17 and 27 h. In total, approximately one-third of cells displayed spontaneous intracellular calcium transients. The calcium transients had an average peak amplitude of 33.3 (+/-2.8%) above baseline, a duration of 52.2 (+/-6.3 s) and occurred with an average frequency of 4.6 (+/-0.4 per hour). Calcium transients were observed in precursor cells located throughout the spinal cord, with the highest percentage of active cells (35.1+/-8%) occurring at a developmental time of 21-22 h. Furthermore these intracellular calcium signals were observed in the presence of tricaine, indicating that they are not generated via sodium-dependent action potentials. In precursor cells loaded with the calcium buffer BAPTA both the frequency and the amplitude of the calcium transients was significantly reduced. The intracellular calcium transients may represent a common activity-independent calcium-mediated mechanism that contributes to the regulation of neuronal development in the spinal cord of the zebrafish embryo during the segmentation and early pharyngula period.

Novel 3-nitro-1H-1,2,4-triazole-based compounds as potential anti-Chagasic drugs: in vivo studies.

BACKGROUND: Chagas disease is caused by the parasite Trypanosoma cruzi, is endemic in Latin America and leads to an estimated 14,000 deaths per year and around 100 million people at risk of infection. Drugs currently used in the treatment of Chagas are old, partially effective and have numerous side effects. METHODOLOGY: We have previously reported that 3-nitro-1H-1,2,4-triazole-based compounds demonstrate significant and selective activity against T. cruzi amastigotes in infected L6 cells via activation of a type I nitroreductase, specific to trypanosomatids. In the present work we evaluated in vivo 13 of these compounds based on their high in vitro potency against T. cruzi (IC50 < 1 µM) and selectivity (SI: toxicity to L6 cells/toxicity against T. cruzi amastigotes > 200). Representative compounds of different chemical classes were included. A fast luminescence assay with transgenic parasites that express luciferase, and live imaging techniques were used. A total of 11 out of 13 compounds demonstrated significant antichagasic activity when administered intraperitoneally for 5-10 days at relatively small doses. The best in vivo activity was demonstrated by amides and sulfonamide derivatives. ADMET studies were performed for specific compounds. CONCLUSION: At least three compounds were identified as effective, non-toxic antichagasic agents suitable for further development.

Evaluating the developmental toxicity of trypanocidal nitroaromatic compounds on zebrafish.

Current therapies against African and American trypanosomiasis are problematic and with no immediate prospect of a vaccine there is an urgent need for cheap, more effective treatments. To aid the drug discovery pipeline, we report a novel in vivo screening approach using zebrafish (Danio rerio) embryos as a means of rapidly assessing a compounds developmental toxicity. This technique, amenable to high-throughput screening, was validated using several trypanocidal nitroaromatic prodrugs including nifurtimox and benznidazole.

Female and male gamete mitochondria are distinct and complementary in transcription, structure, and genome function.

Respiratory electron transport in mitochondria is coupled to ATP synthesis while generating mutagenic oxygen free radicals. Mitochondrial DNA mutation then accumulates with age, and may set a limit to the lifespan of individual, multicellular organisms. Why is this mutation not inherited? Here we demonstrate that female gametes-oocytes-have unusually small and simple mitochondria that are suppressed for DNA transcription, electron transport, and free radical production. By contrast, male gametes-sperm-and somatic cells of both sexes transcribe mitochondrial genes for respiratory electron carriers and produce oxygen free radicals. This germ-line division between mitochondria of sperm and egg is observed in both the vinegar fruitfly and the zebrafish-species spanning a major evolutionary divide within the animal kingdom. We interpret these findings as an evidence that oocyte mitochondria serve primarily as genetic templates, giving rise, irreversibly and in each new generation, to the familiar energy-transducing mitochondria of somatic cells and male gametes. Suppressed mitochondrial metabolism in the female germ line may therefore constitute a mechanism for increasing the fidelity of mitochondrial DNA inheritance.

Ryanodine receptors, a family of intracellular calcium ion channels, are expressed throughout early vertebrate development.

BACKGROUND: Calcium signals ([Ca2+]i) direct many aspects of embryo development but their regulation is not well characterised. Ryanodine receptors (RyRs) are a family of intracellular Ca2+ release channels that control the flux of Ca2+ from internal stores into the cytosol. RyRs are primarily known for their role in excitation-contraction coupling in adult striated muscle and ryr gene mutations are implicated in several human diseases. Current evidence suggests that RyRs do not have a major role to play prior to organogenesis but regulate tissue differentiation. FINDINGS: The sequences of the five zebrafish ryr genes were confirmed, their evolutionary relationship established and the primary sequences compared to other vertebrates, including humans. RyRs are differentially expressed in slow (ryr1a), fast (ryr3) and both types (ryr1b) of developing skeletal muscle. There are two ryr2 genes (ryr2a and ryr2b) which are expressed exclusively in developing CNS and cardiac tissue, respectively. In addition, ryr3 and ryr2a mRNA is detectable in the initial stages of development, prior to embryonic axis formation. CONCLUSIONS: Our work reveals that zebrafish ryr genes are differentially expressed throughout the developing embryo from cleavage onwards. The data suggests that RyR-regulated Ca2+ signals are associated with several aspects of embryonic development, from organogenesis through to the differentiation of the musculoskeletal, cardiovascular and nervous system. These studies will facilitate further work to explore the developmental function of RyRs in each of these tissue types.

The ATPase-dependent chaperoning activity of Hsp90a regulates thick filament formation and integration during skeletal muscle myofibrillogenesis.

The mechanisms that regulate sarcomere assembly during myofibril formation are poorly understood. In this study, we characterise the zebrafish sloth(u45) mutant, in which the initial steps in sarcomere assembly take place, but thick filaments are absent and filamentous I-Z-I brushes fail to align or adopt correct spacing. The mutation only affects skeletal muscle and mutant embryos show no other obvious phenotypes. Surprisingly, we find that the phenotype is due to mutation in one copy of a tandemly duplicated hsp90a gene. The mutation disrupts the chaperoning function of Hsp90a through interference with ATPase activity. Despite being located only 2 kb from hsp90a, hsp90a2 has no obvious role in sarcomere assembly. Loss of Hsp90a function leads to the downregulation of genes encoding sarcomeric proteins and upregulation of hsp90a and several other genes encoding proteins that may act with Hsp90a during sarcomere assembly. Our studies reveal a surprisingly specific developmental role for a single Hsp90 gene in a regulatory pathway controlling late steps in sarcomere assembly.

Molecular and functional characterization of inositol trisphosphate receptors during early zebrafish development.

Fluctuations in cytosolic Ca(2+) are crucial for a variety of cellular processes including many aspects of development. Mobilization of intracellular Ca(2+) stores via the production of inositol trisphosphate (IP(3)) and the consequent activation of IP(3)-sensitive Ca(2+) channels is a ubiquitous means by which diverse stimuli mediate their cellular effects. Although IP(3) receptors have been well studied at fertilization, information regarding their possible involvement during subsequent development is scant. In the present study we examined the role of IP(3) receptors in early development of the zebrafish. We report the first molecular analysis of zebrafish IP(3) receptors which indicates that, like mammals, the zebrafish genome contains three distinct IP(3) receptor genes. mRNA for all isoforms was detectable at differing levels by the 64 cell stage, and IP(3)-induced Ca(2+) transients could be readily generated (by flash photolysis) in a controlled fashion throughout the cleavage period in vivo. Furthermore, we show that early blastula formation was disrupted by pharmacological blockade of IP(3) receptors or phospholipase C, by molecular inhibition of the former by injection of IRBIT (IP(3) receptor-binding protein released with IP(3)) and by depletion of thapsigargin-sensitive Ca(2+) stores after completion of the second cell cycle. Inhibition of Ca(2+) entry or ryanodine receptors, however, had little effect. Our work defines the importance of IP(3) receptors during early development of a genetically and optically tractable model vertebrate organism.

Use of transgenic zebrafish reporter lines to study calcium signalling in development.

Calcium signals are associated with many of the events common to animal development. Understanding the role of these calcium signals requires the ability to visualise and manipulate calcium levels in the developing embryo. Recent work has led to the development of sensitive protein-based probes that can be used to generate transgenic animals for the analysis of calcium signalling in vivo. This paper focuses on the use of genetically encoded calcium probes to follow calcium signals in zebrafish. It reviews progress and speculates on the potential for use in the future.

Acetylcholine and calcium signalling regulates muscle fibre formation in the zebrafish embryo.

Nerve activity is known to be an important regulator of muscle phenotype in the adult, but its contribution to muscle development during embryogenesis remains unresolved. We used the zebrafish embryo and in vivo imaging approaches to address the role of activity-generated signals, acetylcholine and intracellular calcium, in vertebrate slow muscle development. We show that acetylcholine drives initial muscle contraction and embryonic movement via release of intracellular calcium from ryanodine receptors. Inhibition of this activity-dependent pathway at the level of the acetylcholine receptor or ryanodine receptor did not disrupt slow fibre number, elongation or migration but affected myofibril organisation. In mutants lacking functional acetylcholine receptors myofibre length increased and sarcomere length decreased significantly. We propose that calcium is acting via the cytoskeleton to regulate myofibril organisation. Within a myofibre, sarcomere length and number are the key parameters regulating force generation; hence our findings imply a critical role for nerve-mediated calcium signals in the formation of physiologically functional muscle units during development.