Faculty Bibliography

Thyroid hormones have long been known to have a range of effects on the cardiovascular system. However, significant knowledge gaps exist concerning the precise molecular and biochemical mechanisms governing these effects and the optimal strategies for management of abnormalities in thyroid function in patients with and without preexisting cardiovascular disease. In September 2017, The National Heart, Lung, and Blood Institute convened a Working Group with the goal of developing priorities for future scientific research relating thyroid dysfunction to the progression of cardiovascular disease. The Working Group reviewed and discussed the roles of normal thyroid physiology, the consequences of thyroid dysfunction, and the effects of therapy in three cardiovascular areas: cardiac electrophysiology and arrhythmias, the vasculature and atherosclerosis, and the myocardium and heart failure. This report describes the current state of the field, outlines barriers and challenges to progress, and proposes research opportunities to advance the field, including strategies for leveraging novel approaches using omics and big data. The Working Group recommended research in three broad areas: 1) investigation into the fundamental biology relating thyroid dysfunction to the development of cardiovascular disease and into the identification of novel biomarkers of thyroid hormone action in cardiovascular tissues; 2) studies that define subgroups of patients with thyroid dysfunction amenable to specific preventive strategies and interventional therapies related to cardiovascular disease; and 3) clinical trials focused on improvement in cardiovascular performance and cardiovascular outcomes through treatment with thyroid hormone or thyromimetic drugs.

There is increasing scrutiny from healthcare organizations towards the utility and associated costs of imaging. MRI has traditionally been used as a high-end modality, and although shown extremely important for many types of clinical scenarios, it has been suggested as too expensive by some. This editorial will try and explain how value should be addressed and gives some insights and practical examples of how value of MRI can be increased. It requires a global effort to increase accessibility, value for money, and impact on patient management. We hope this editorial sheds some light and gives some indications of where the field may wish to address some of its research to proactively demonstrate the value of MRI. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:e14-e25.

Due its unique structure and its reported potent antifungal activity, the marine polyketide hippolachnin A (1) has attracted much attention in the synthetic community. Herein, we describe the development of a concise, diversifiable and scalable synthesis of the racemic natural product, which serves as a platform for the generation of bioactive analogues. Biological testing of our synthetic material did not confirm the reported antifungal activity of hippolachnin A but unraveled moderate activity against nematodes and microbes.

Purpose: SparseCT is a practical compressed sensing approach for CT dose reduction, which undersamples each view along the row dimension with a multislit collimator (MSC). The MSC is mounted between tube and patient and moves along the row direction to change the undersampling pattern along the row dimension for each view. This study aims to investigate the impact of MSC motion on SparseCT image quality.
Method(s): A SparseCT prototype was built with the MSC installed on a state-of-art clinical CT scanner. The MSC is a tungsten plate with periodic slits parallel to detector row direction. The slit separation is 3 times wider than the slit width, such that the dose reduction factor is 3. A liver phantom was scanned repeatedly at various MSC locations, each sampling different rows. The MSC was static during each scan, but 'dynamic MSC' scans were retrospectively simulated by stitching together projections from different scans. Six MSC motions were tested, including 3 patterns (linear, back-and-forth, and random) and 2 speeds (1 and 5 row(s)/projection). The dynamic MSC scans were reconstructed iteratively using a compressed sensing reconstruction algorithm that enforces 3D sparsity using total variation regularization. Image quality for different motions were compared in terms of PSNR and SSIM.
Result(s): Increasing MSC motion speed significantly improved PSNR and SSIM while the effect of motion pattern was negligible. Higher motion speeds also markedly reduced undersampling artifacts observed around high attenuation, high frequency objects such as the spine. The best PSNR and SSIM were achieved using a combination of linear motion and a speed of 5 rows/projection.
Conclusion(s): The motion of the MSC has a significant impact on the performance of SparseCT. Higher motion speed yields more incoherent undersampling artifacts and thus improves reconstruction quality

Identify correlates of nicotine dependence [lifetime (l) and ongoing (o)] in adults with attention-deficit/hyperactivity disorder (ADHD) in childhood. We conducted a 33-year prospective follow-up of boys (mean age 8) with combined type ADHD (n = 135/207, 65% original sample). Correlates of nicotine dependence in adulthood were selected from characteristics obtained in childhood and adolescence. Among selected childhood features, only immature behavior was significantly related to nicotine dependence (OR(o) = 0.29, p = 0.02), indexing decreased risk. In contrast, several adolescent variables significantly correlated (p < 0.01) with nicotine dependence at mean age 41, including alcohol substance use disorder (SUD, OR(l) = 4.97), non-alcohol SUD (OR(o) = 4.33/OR(l) = 10.93), parental antisocial personality disorder (OR(l) = 4.42), parental SUD (OR(l) = 3.58), dropped out of school (OR(l) = 2.29), impulsivity (OR(o) = 1.53/OR(l) = 1.59), hyperactivity (OR(o) = 1.38), and number of antisocial behaviors (OR(o) = 1.10/OR(l) = 1.14). Results highlight the role of adolescent psychopathology in the development of nicotine dependence, motivating prospective longitudinal efforts to better define the developmental trajectories of risk and protection.

Child development research highlights caregiver regulation of infant physiology and behavior as a key feature of early life attachment, although mechanisms for maternal control of infant neural circuits remain elusive. Here we explored the neurobiology of maternal regulation of infant fear using neural network and molecular levels of analysis in a rodent model. Previous research has shown maternal suppression of amygdala-dependent fear learning during a sensitive period. Here we characterize changes in neural networks engaged during maternal regulation and the transition to infant self-regulation. Metabolic mapping of 2-deoxyglucose uptake during odor-shock conditioning in postnatal day (PN)14 rat pups showed that maternal presence blocked fear learning, disengaged mesolimbic circuitry, basolateral amygdala (BLA), and plasticity-related AMPA receptor subunit trafficking. At PN18, when maternal presence only socially buffers threat learning (similar to social modulation in adults), maternal presence failed to disengage the mesolimbic dopaminergic system, and failed to disengage both the BLA and plasticity-related AMPA receptor subunit trafficking. Further, maternal presence failed to block threat learning at PN14 pups following abuse, and mesolimbic dopamine engagement and AMPA were not significantly altered by maternal presence-analogous to compromised maternal regulation of children in abusive relationships. Our results highlight three key features of maternal regulation: (1) maternal presence blocks fear learning and amygdala plasticity through age-dependent suppression of amygdala AMPA receptor subunit trafficking, (2) maternal presence suppresses engagement of brain regions within the mesolimbic dopamine circuit, and (3) early-life abuse compromises network and molecular biomarkers of maternal regulation, suggesting reduced social scaffolding of the brain.

Neonatal brain lesions cause deficits in structure and function of the cerebral cortex that sometimes are not fully expressed until adolescence. To better understand the onset and persistence of changes caused by postnatal day 7 (P7) ethanol treatment, we examined neocortical cell numbers, volume, surface area and thickness from neonatal to post-adolescent ages. In control mice, total neuron number decreased from P8 to reach approximately stable levels at about P30, as expected from normal programmed cell death. Cortical thickness reached adult levels by P14, but cortical volume and surface area continued to increase from juvenile (P20-30) to post-adolescent (P54-93) ages. P7 ethanol caused a reduction of total neurons by P14, but this deficit was transient, with later ages having only small and non-significant reductions. Previous studies also reported transient neuron loss after neonatal lesions that might be partially explained by an acute acceleration of normally occurring programmed cell death. GABAergic neurons expressing parvalbumin, calretinin, or somatostatin were reduced by P14, but unlike total neurons the reductions persisted or increased in later ages. Cortical volume, surface area and thickness were also reduced by P7 ethanol. Cortical volume showed evidence of a transient reduction at P14, and then was reduced again in post-adolescent ages. The results show a developmental sequence of neonatal ethanol effects. By juvenile ages the cortex overcomes the P14 deficit of total neurons, whereas P14 GABA cell deficits persist. Cortical volume reductions were present at P14, and again in post-adolescent ages.

Presynaptic boutons support neurotransmitter release with nanoscale precision at sub-millisecond timescales. Studies over the past two decades have revealed a rich tapestry of molecular players governing synaptic vesicle fusion at highly specialized release sites in the active zone (AZ). However, the spatiotemporal organization of release at active synapses remains elusive, in part owing to the extremely small size of the AZ and the limited resolution of conventional approaches. Recent advances in fluorescence nanoscopy have revolutionized direct investigation of presynaptic release organization and dynamics. We discuss here recent nanoscopy-based studies of the molecular architecture, the spatial organization and dynamic regulation of release sites, and the mechanisms of release site replenishment. These findings have uncovered previously unknown levels of structural and functional organization at central synapses, with important implications for synaptic transmission and plasticity.