Practice Patterns of Pancreatic Surgery Within the Military.

INTRODUCTION: Pancreatic surgery is technically challenging, with mortality rates at high-volume centers ranging from 0% to 5%. An inverse relationship between surgeon volume and perioperative mortality has been reported suggesting that patients benefit from experienced surgeons at high-volume centers. There is little published on the volume of pancreatic surgeries performed in military treatment facilities (MTF) and there is no centralization policy regarding pancreatic surgery. This study evaluates pancreatic procedures at MTFs. We hypothesize that a small group of MTFs perform most pancreatic procedures, including more complex pancreatic surgeries. METHODS: This is a retrospective review of de-identified data from MHS Mart (M2) from 2014 to 2020. The database contains patient data from all Defense Health Agency treatment facilities. Variables collected include number and types of pancreatic procedures performed and patient demographics. The primary endpoint was the number and type of surgery for each MTF. RESULTS: Twenty-six MTFs performed pancreatic surgeries from 2014 to 2020. There was a significant decrease in the number of cases from 2014 to 2020. Nine hospitals performed one surgery over eight years. The most common surgery was a distal pancreatectomy, followed by a pancreaticoduodenectomy. There was a decrease in the number of pancreaticoduodenectomies and distal pancreatectomies performed over this period. CONCLUSIONS: Pancreatic surgery is being performed at few MTFs with a downward trajectory over time. Further studies would be needed to assess the impact on patient care regarding postoperative complications, barriers to timely patient care, and impact on readiness of military surgeons.

Practice patterns of hepatobiliary surgery within the military.

BACKGROUND: The purpose of this study is to evaluate the trends of hepatobiliary surgeries performed at military hospitals and to discuss potential implications on resident training and military readiness. While there is data to suggest centralization of surgical specialty services leads to improved patient outcomes, the military does not currently have a specific centralization policy. Implementation of such a policy could potentially impact resident training and readiness of military surgeons. Even in the absence of such a policy, there may still be a trend toward centralization of more complex surgeries like hepatobiliary surgeries. The present study evaluates the numbers and types of hepatobiliary procedures performed at military hospitals. METHODS: This study is a retrospective review of de-identified data from Military Health System Mart (M2) from 2014 to 2020. The M2 database contains patient data from all Defense Health Agency treatment facilities, encompassing all branches of the United States Military. Variables collected include number and types of hepatobiliary procedures performed and patient demographics. The primary endpoint was the number and type of surgery for each medical facility. Linear regression was used to evaluate significant trends in numbers of surgeries over time. RESULTS: Fifty-five military hospitals performed hepatobiliary surgeries from 2014 to 2020. A total of 1,087 hepatobiliary surgeries were performed during this time; cholecystectomies, percutaneous procedures, and endoscopic procedures were excluded. There was no significant decrease in overall case volume. The most commonly performed hepatobiliary surgery was "unlisted laparoscopic liver procedure." The military training facility with the most hepatobiliary cases was Brooke Army Medical Center. CONCLUSION: The number of hepatobiliary surgeries performed in military hospitals has not significantly decreased over the years 2014-2020, despite a national trend toward centralization. Centralization of hepatobiliary surgeries in the future may impact residency training as well as military medical readiness.

Caveolin-3 and Caveolae regulate ventricular repolarization.

RATIONALE: Flask-shaped invaginations of the cardiomyocyte sarcolemma called caveolae require the structural protein caveolin-3 (Cav-3) and host a variety of ion channels, transporters, and signaling molecules. Reduced Cav-3 expression has been reported in models of heart failure, and variants in CAV3 have been associated with the inherited long-QT arrhythmia syndrome. Yet, it remains unclear whether alterations in Cav-3 levels alone are sufficient to drive aberrant repolarization and increased arrhythmia risk. OBJECTIVE: To determine the impact of cardiac-specific Cav-3 ablation on the electrophysiological properties of the adult mouse heart. METHODS AND RESULTS: Cardiac-specific, inducible Cav3 homozygous knockout (Cav-3KO) mice demonstrated a marked reduction in Cav-3 expression by Western blot and loss of caveolae by electron microscopy. However, there was no change in macroscopic cardiac structure or contractile function. The QTc interval was increased in Cav-3KO mice, and there was an increased propensity for ventricular arrhythmias. Ventricular myocytes isolated from Cav-3KO mice exhibited a prolonged action potential duration (APD) that was due to reductions in outward potassium currents (Ito, Iss) and changes in inward currents including slowed inactivation of ICa,L and increased INa,L. Mathematical modeling demonstrated that the changes in the studied ionic currents were adequate to explain the prolongation of the mouse ventricular action potential. Results from human iPSC-derived cardiomyocytes showed that shRNA knockdown of Cav-3 similarly prolonged APD. CONCLUSION: We demonstrate that Cav-3 and caveolae regulate cardiac repolarization and arrhythmia risk via the integrated modulation of multiple ionic currents.

Effect of three-dimensional intraoperative imaging on surgical outcomes with breast conservation therapy.

BACKGROUND: Breast conservation therapy (BCT) is frequently performed for breast cancer and associated with a significant risk for positive margins. Intraoperative three-dimensional (3-D) tomosynthesis potentially could limit the risk of positive margins. METHODS: Retrospective review of an institutional breast cancer registry. Evaluated BCT cases for a two year time period prior to and after the introduction of intraoperative 3-D tomosynthesis. Primary outcome was the effect of 3-D tomosynthesis on margin positivity rates. Secondary measures were the impact of 3-D tomosynthesis on additional margin procurements at the index surgery and operative time. RESULTS: A total of 228 cases were evaluated with 106 cases utilizing 3-D tomosynthesis and 122 cases with standard imaging. No significant difference in margin positivity rates between the cohorts at 23.9% versus 15.8% for 3-D tomosynthesis and standard imaging respectively (OR 1.53, CI 0.772-3.032, P = 0.221). 3-D tomosynthesis was associated with increased margin procurement rates (OR 2.34, 95%CI 1.303-4.190, P = 0.004) and longer operative times (P < 0.001). CONCLUSION: Intraoperative 3-D tomosynthesis was not found to limit margin positivity rates or improve the performance of the procedure.

Shared decision-making for postoperative opioid prescribing and preoperative pain management education decreases excess opioid burden.

INTRODUCTION: Managing postoperative pain requires an individualized approach in order to balance adequate pain control with risk of persistent opioid use and narcotic abuse associated with inappropriately outsized narcotic prescriptions. Shared decision-making has been proposed to address individual pain management needs. We report here the results of a quality improvement initiative instituting prescribing guidelines using shared decision-making and preoperative pain expectation and management education to decrease excess opioid pills after surgery and improve patient satisfaction. METHODS: Pre-intervention prescribing habits were obtained by retrospective review perioperative pharmacy records for patients undergoing general surgeries in the 24 months prior to initiation of intervention. Patients scheduled to undergo General Surgery procedures were given a survey at their preoperative visit. Preoperative education was performed by the surgical team as a part of the Informed Consent process using a standardized handout and patients were asked to choose the number of narcotic pills they wished to obtain within prescribing recommendations. Postoperative surveys were administered during or after their 2-week postoperative visit. RESULTS: 131 patients completed pre-intervention and post-intervention surveys. The average prescription size decreased from 12.29 oxycodone pills per surgery prior to institution of pathway to 6.80 pills per surgery after institution of pathway (p < 0.001). The percentage of unused pills after surgery decreased from an estimated 70.5% pre-intervention to 48.5% (p < 0.001) post-intervention. 61.1% of patients with excess pills returned or planned to return medication to the pharmacy with 16.8% of patients reporting alternative disposal of excess medication. Patient-reported satisfaction was higher with current surgery compared to prior surgeries (p < 0.001). CONCLUSION: Institution of procedure-specific prescribing recommendations and preoperative pain management education using shared decision-making between patient and provider decreases opioid excess burden, resulting in fewer unused narcotic pills entering the community. Furthermore, allowing patients to participate in decision-making with their provider results in increased patient satisfaction.

Improved Outcomes for Trauma Patients in a Military Treatment Facility After Initiation of an American College of Surgeons-Verified Trauma Program.

INTRODUCTION: The National Defense Authorization Act of 2017 indicated the need for a national strategy to improve trauma care among military treatment facilities (MTFs). Part of the proposed strategy to improve trauma outcomes was to convert identified MTFs into verified trauma centers. The American College of Surgeons (ACS) verifies trauma centers through an evaluation process based on available resources at a facility. It has been proven that trauma centers, specifically those verified by the ACS, have improved trauma outcomes. In 2017, we implemented steps to become a level III trauma program, according to the standards for designation by the state and verification through the ACS. The goal of this retrospective review is to evaluate the impact of this implementation with regard to both patient care and the MTF. MATERIALS AND METHODS: Data from a single-MTF trauma registry from 2018, at the initiation of the trauma program, to present were reviewed. Outcomes were selected based upon the ACS verification criteria. Specifically, emergency department length of stay (ED LOS), nonsurgical admissions, injury severity score, diversion rates, and time to operating room were reviewed. Statistical analyses were performed using Student's t-tests. Institutional review board (IRB) approval was not required for this study as it was performed as a quality improvement project using deidentified data. RESULTS: ED LOS decreased significantly after implementation of the trauma program from an average of 6.43 h in 2018 to 4.73 h in 2019 and 4.6 h in 2020 (P < .04). Nonsurgical admissions decreased significantly from 57.8% in 2018, with rates of <20% in all subsequent years (P < .01). The average injury severity score increased from 5.61 in 2018 to 7.52 in 2020 (P < .01) and 7.27 in 2021 (P < .01). Diversion rates also decreased from >5% in 2018 to 0% in 2021. CONCLUSIONS: The establishment of a trauma program in accordance with the standards of the ACS for verification improved metrics of care for trauma patients at our MTF. This implementation as part of the local trauma system also led to increased injury severity seen by the MTF, which enhances readiness for its providers.

Economical Utilization of Health Information with Learning Healthcare System Data Commons.

Finding, accessing, sharing, and analyzing patient data from a clinical setting for collaborative research has continually proven to be a challenge in healthcare organizations. The human and technological architecture required to perform these services exist at the largest academic institutions but are usually under-funded. At smaller, less academically focused healthcare organizations across the United States, where the majority of care is delivered, they are generally absent. Here we propose a solution called the Learning Healthcare System Data Commons where cost is usage-based and the most basic elements are designed to be extensible, allowing it to evolve with the changing landscape of healthcare. Herein we also discuss our reference implementation of this platform tailored specifically for operational sustainability and governance using the data generated in a hospital setting for research, quality, and educational purposes.

Absence of "Cytokine Storm" in Hospitalized COVID-19 Patients: A Retrospective Cohort Study.

Background: A rapidly growing number of publications cite "cytokine storm" as a contributing factor in coronavirus disease 2019 (COVID-19) pathology. However, a few recent reports led to questioning of "cytokine storm" theory in COVID-19. This study's primary goal is to determine if exaggerated cytokine response in the range of a "cytokine storm" develops during the initial weeks of hospitalization in COVID-19 patients. Methods: Five proinflammatory cytokines reported to be involved in "cytokine storm" and elevated in COVID-19 (IL-6, IL-8, TNF-α, MCP-1, and IP-10) were analyzed in COVID-19, influenza (with "cytokine storm": CS), and burn injury patients. The effect of dexamethasone use on cytokine response in COVID-19 was also analyzed. Results: None of the five cytokines in COVID-19 patients reached the lower threshold (95% CI) of the influenza (CS) group at any point during the study period. Furthermore, mean concentrations of all five cytokines in the influenza (CS) group and IL-6, IL-8, TNF-α in the burn group were significantly greater than in COVID-19 patients (p < 0.01). Dexamethasone treatment did not significantly alter the concentrations of any of the cytokines analyzed. Conclusions: Exaggerated cytokine response similar to "cytokine storm" was not observed in COVID-19 patients during two weeks of hospitalization.

Degradation of T-Tubular Microdomains and Altered cAMP Compartmentation Lead to Emergence of Arrhythmogenic Triggers in Heart Failure Myocytes: An in silico Study.

Heart failure (HF) is one of the most common causes of morbidity and mortality worldwide. Although many patients suffering from HF die from sudden cardiac death caused by arrhythmias, the mechanism linking HF remodeling to an increased arrhythmogenic propensity remains incomplete. HF is typically characterized by a progressive loss of transverse tubule (T-tubule) domains, which leads to an altered distribution of L-type calcium channels (LTCCs). Microdomain degradation also causes the disruption of the ß2 adrenergic receptor (ß2AR) and phosphodiesterase (PDE) signaling localization, normally confined to the dyadic space. The goal of this study was to analyze how these subcellular changes affect the function of LTCCs and lead to the emergence of ventricular cell-level triggers of arrhythmias. To accomplish this, we developed a novel computational model of a human ventricular HF myocyte in which LTCCs were divided into six different populations, based on their location and signaling environment they experience. To do so, we included T-tubular microdomain remodeling which led to a subset of LTCCs to be redistributed from the T-tubular to the surface membrane and allowed for different levels of phosphorylation of LTCCs by PKA, based on the presence of ß2ARs and PDEs. The model was used to study the behavior of the LTCC current (ICaL) under basal and sympathetic stimulation and its effect on cellular action potential. Our results showed that channels redistributed from the T-tubular membrane to the bulk of the sarcolemma displayed an altered function in their new, non-native signaling domain. Incomplete calcium dependent inactivation, which resulted in a longer-lasting and larger-in-magnitude LTCC current, was observed when we decoupled LTCCs from ryanodine receptors and removed them from the dyadic space. The magnitude of the LTCC current, especially in the surface sarcolemma, was also increased via phosphorylation by the redistributed ß2ARs and PDEs. These changes in LTCC current led to the development of early afterdepolarizations. Thus, our study shows that altered LTCC function is a potential cause for the emergence of cell-level triggers of arrhythmia, and that ß2ARs and PDEs present useful therapeutic targets for treatment of HF and prevention of sudden cardiac death.

Efficient Computational Modeling of Human Ventricular Activation and Its Electrocardiographic Representation: A Sensitivity Study.

Patient-specific models of the ventricular myocardium, combined with the computational power to run rapid simulations, are approaching the level where they could be used for personalized cardiovascular medicine. A major remaining challenge is determining model parameters from available patient data, especially for models of the Purkinje-myocardial junctions (PMJs): the sites of initial ventricular electrical activation. There are no non-invasive methods for localizing PMJs in patients, and the relationship between the standard clinical ECG and PMJ model parameters is underexplored. Thus, this study aimed to determine the sensitivity of the QRS complex of the ECG to the anatomical location and regional number of PMJs. The QRS complex was simulated using an image-based human torso and biventricular model, and cardiac electrophysiology was simulated using Cardioid. The PMJs were modeled as discrete current injection stimuli, and the location and number of stimuli were varied within initial activation regions based on published experiments. Results indicate that the QRS complex features were most sensitive to the presence or absence of four "seed" stimuli, and adjusting locations of nearby "regional" stimuli provided finer tuning. Decreasing number of regional stimuli by an order of magnitude resulted in virtually no change in the QRS complex. Thus, a minimal 12-stimuli configuration was identified that resulted in physiological excitation, defined by QRS complex feature metrics and ventricular excitation pattern. Overall, the sensitivity results suggest that parameterizing PMJ location, rather than number, be given significantly higher priority in future studies creating personalized ventricular models from patient-derived ECGs.

Simultaneous electrical recording of cardiac electrophysiology and contraction on chip.

Prevailing commercialized cardiac platforms for in vitro drug development utilize planar microelectrode arrays to map action potentials, or impedance sensing to record contraction in real time, but cannot record both functions on the same chip with high spatial resolution. Here we report a novel cardiac platform that can record cardiac tissue adhesion, electrophysiology, and contractility on the same chip. The platform integrates two independent yet interpenetrating sensor arrays: a microelectrode array for field potential readouts and an interdigitated electrode array for impedance readouts. Together, these arrays provide real-time, non-invasive data acquisition of both cardiac electrophysiology and contractility under physiological conditions and under drug stimuli. Human induced pluripotent stem cell-derived cardiomyocytes were cultured as a model system, and used to validate the platform with an excitation-contraction decoupling chemical. Preliminary data using the platform to investigate the effect of the drug norepinephrine are combined with computational efforts. This platform provides a quantitative and predictive assay system that can potentially be used for comprehensive assessment of cardiac toxicity earlier in the drug discovery process.

Early somatic mosaicism is a rare cause of long-QT syndrome.

Somatic mosaicism, the occurrence and propagation of genetic variation in cell lineages after fertilization, is increasingly recognized to play a causal role in a variety of human diseases. We investigated the case of life-threatening arrhythmia in a 10-day-old infant with long QT syndrome (LQTS). Rapid genome sequencing suggested a variant in the sodium channel NaV1.5 encoded by SCN5A, NM_000335:c.5284G > T predicting p.(V1762L), but read depth was insufficient to be diagnostic. Exome sequencing of the trio confirmed read ratios inconsistent with Mendelian inheritance only in the proband. Genotyping of single circulating leukocytes demonstrated the mutation in the genomes of 8% of patient cells, and RNA sequencing of cardiac tissue from the infant confirmed the expression of the mutant allele at mosaic ratios. Heterologous expression of the mutant channel revealed significantly delayed sodium current with a dominant negative effect. To investigate the mechanism by which mosaicism might cause arrhythmia, we built a finite element simulation model incorporating Purkinje fiber activation. This model confirmed the pathogenic consequences of cardiac cellular mosaicism and, under the presenting conditions of this case, recapitulated 2:1 AV block and arrhythmia. To investigate the extent to which mosaicism might explain undiagnosed arrhythmia, we studied 7,500 affected probands undergoing commercial gene-panel testing. Four individuals with pathogenic variants arising from early somatic mutation events were found. Here we establish cardiac mosaicism as a causal mechanism for LQTS and present methods by which the general phenomenon, likely to be relevant for all genetic diseases, can be detected through single-cell analysis and next-generation sequencing.

Microdomain-Specific Modulation of L-Type Calcium Channels Leads to Triggered Ventricular Arrhythmia in Heart Failure.

RATIONALE: Disruption in subcellular targeting of Ca(2+) signaling complexes secondary to changes in cardiac myocyte structure may contribute to the pathophysiology of a variety of cardiac diseases, including heart failure (HF) and certain arrhythmias. OBJECTIVE: To explore microdomain-targeted remodeling of ventricular L-type Ca(2+) channels (LTCCs) in HF. METHODS AND RESULTS: Super-resolution scanning patch-clamp, confocal and fluorescence microscopy were used to explore the distribution of single LTCCs in different membrane microdomains of nonfailing and failing human and rat ventricular myocytes. Disruption of membrane structure in both species led to the redistribution of functional LTCCs from their canonical location in transversal tubules (T-tubules) to the non-native crest of the sarcolemma, where their open probability was dramatically increased (0.034±0.011 versus 0.154±0.027, P<0.001). High open probability was linked to enhance calcium-calmodulin kinase II-mediated phosphorylation in non-native microdomains and resulted in an elevated ICa,L window current, which contributed to the development of early afterdepolarizations. A novel model of LTCC function in HF was developed; after its validation with experimental data, the model was used to ascertain how HF-induced T-tubule loss led to altered LTCC function and early afterdepolarizations. The HF myocyte model was then implemented in a 3-dimensional left ventricle model, demonstrating that such early afterdepolarizations can propagate and initiate reentrant arrhythmias. CONCLUSIONS: Microdomain-targeted remodeling of LTCC properties is an important event in pathways that may contribute to ventricular arrhythmogenesis in the settings of HF-associated remodeling. This extends beyond the classical concept of electric remodeling in HF and adds a new dimension to cardiovascular disease.

Dysfunction of the Voltage-Gated K+ Channel ß2 Subunit in a Familial Case of Brugada Syndrome.

BACKGROUND: The Brugada syndrome is an inherited cardiac arrhythmia associated with high risk of sudden death. Although 20% of patients with Brugada syndrome carry mutations in SCN5A, the molecular mechanisms underlying this condition are still largely unknown. METHODS AND RESULTS: We combined whole-exome sequencing and linkage analysis to identify the genetic variant likely causing Brugada syndrome in a pedigree for which SCN5A mutations had been excluded. This approach identified 6 genetic variants cosegregating with the Brugada electrocardiographic pattern within the pedigree. In silico gene prioritization pointed to 1 variant residing in KCNAB2, which encodes the voltage-gated K(+) channel ß2-subunit (Kvß2-R12Q). Kvß2 is widely expressed in the human heart and has been shown to interact with the fast transient outward K(+) channel subunit Kv4.3, increasing its current density. By targeted sequencing of the KCNAB2 gene in 167 unrelated patients with Brugada syndrome, we found 2 additional rare missense variants (L13F and V114I). We then investigated the physiological effects of the 3 KCNAB2 variants by using cellular electrophysiology and biochemistry. Patch-clamp experiments performed in COS-7 cells expressing both Kv4.3 and Kvß2 revealed a significant increase in the current density in presence of the R12Q and L13F Kvß2 mutants. Although biotinylation assays showed no differences in the expression of Kv4.3, the total and submembrane expression of Kvß2-R12Q were significantly increased in comparison with wild-type Kvß2. CONCLUSIONS: Altogether, our results indicate that Kvß2 dysfunction can contribute to the Brugada electrocardiographic pattern.

Cardiac electrophysiological substrate underlying the ECG phenotype and electrogram abnormalities in Brugada syndrome patients.

BACKGROUND: Brugada syndrome (BrS) is a highly arrhythmogenic cardiac disorder, associated with an increased incidence of sudden death. Its arrhythmogenic substrate in the intact human heart remains ill-defined. METHODS AND RESULTS: Using noninvasive ECG imaging, we studied 25 BrS patients to characterize the electrophysiological substrate and 6 patients with right bundle-branch block for comparison. Seven healthy subjects provided control data. Abnormal substrate was observed exclusively in the right ventricular outflow tract with the following properties (in comparison with healthy controls; P<0.005): (1) ST-segment elevation and inverted T wave of unipolar electrograms (2.21±0.67 versus 0 mV); (2) delayed right ventricular outflow tract activation (82±18 versus 37±11 ms); (3) low-amplitude (0.47±0.16 versus 3.74±1.60 mV) and fractionated electrograms, suggesting slow discontinuous conduction; (4) prolonged recovery time (381±30 versus 311±34 ms) and activation-recovery intervals (318±32 versus 241±27 ms), indicating delayed repolarization; (5) steep repolarization gradients (Δrecovery time/Δx=96±28 versus 7±6 ms/cm, Δactivation-recovery interval/Δx=105±24 versus 7±5 ms/cm) at right ventricular outflow tract borders. With increased heart rate in 6 BrS patients, reduced ST-segment elevation and increased fractionation were observed. Unlike BrS, right bundle-branch block had delayed activation in the entire right ventricle, without ST-segment elevation, fractionation, or repolarization abnormalities on electrograms. CONCLUSIONS: The results indicate that both slow discontinuous conduction and steep dispersion of repolarization are present in the right ventricular outflow tract of BrS patients. ECG imaging could differentiate between BrS and right bundle-branch block.

Complex Brugada syndrome inheritance in a family harbouring compound SCN5A and CACNA1C mutations.

Brugada syndrome (BrS) is characterized by ST-segment elevation in the right precordial leads and is associated with increased risk of sudden cardiac death. We have recently reported families with BrS and SCN5A mutations where some affected members do not carry the familial mutation. We evaluated the involvement of additional genetic determinants for BrS in an affected family. We identified three distinct gene variants within a family presenting BrS (5 individuals), cardiac conduction defects (CCD, 3 individuals) and shortened QT interval (4 individuals). The first mutation is nonsense, p.Q1695*, lying within the SCN5A gene, which encodes for NaV1.5, the α-subunit of the cardiac Na(+) channel. The second mutation is missense, p.N300D, and alters the CACNA1C gene, which encodes the α-subunit CaV1.2 of the L-type cardiac Ca(2+) channel. The SCN5A mutation strictly segregates with CCD. Four out of the 5 BrS patients carry the CACNA1C variant, and three of them present shortened QT interval. One of the BrS patients carries none of these mutations but a rare variant located in the ABCC9 gene as well as his asymptomatic mother. Patch-clamp studies identified a loss-of-function of the mutated CaV1.2 channel. Western-blot experiments showed a global expression defect while increased mobility of CaV1.2 channels on cell surface was revealed by FRAP experiments. Finally, computer simulations of the two mutations recapitulated patient phenotypes. We report a rare CACNA1C mutation as causing BrS and/or shortened QT interval in a family also carrying a SCN5A stop mutation, but which does not segregate with BrS. This study underlies the complexity of BrS inheritance and its pre-symptomatic genetic screening interpretation.

Correlates of implicit cognitive line length representation in two-dimensional space.

Twenty-eight sex- and age-matched participants, half dextrals and half sinstrals, were instructed to move a pen-sized planometer three inches (7.6 cm) while blindfolded. Under separate trials, movements were made at four angles, towards and away from the body, and at two distances from the body (30 cm, 53 cm). Half were made with the right hand and half with the left hand. Line estimates increased in length across blocks of trials in a linear fashion and progressively overestimated the three-inch imagined criterion. Lines made moving towards the body were longer than those made moving away from the body, implying an egocentric frame of reference in making the estimates. Line estimates made at an oblique angle differed significantly from estimates made at other angles. No influences of sex, handedness, or the hand used in making the estimates were observed. The findings suggest that motoric estimates of line lengths made without visual cues-a unique measure of an implicit cognitive concept-are significantly altered by temporal and spatial factors, but not by sex or hemispheric laterality.

Caveolin-3 regulates compartmentation of cardiomyocyte beta2-adrenergic receptor-mediated cAMP signaling.

The purpose of this study was to investigate whether caveolin-3 (Cav3) regulates localization of ß2-adrenergic receptor (ß2AR) and its cAMP signaling in healthy or failing cardiomyocytes. We co-expressed wildtype Cav3 or its dominant-negative mutant (Cav3DN) together with the Förster resonance energy transfer (FRET)-based cAMP sensor Epac2-camps in adult rat ventricular myocytes (ARVMs). FRET and scanning ion conductance microscopy were used to locally stimulate ß2AR and to measure cytosolic cAMP. Cav3 overexpression increased the number of caveolae and decreased the magnitude of ß2AR-cAMP signal. Conversely, Cav3DN expression resulted in an increased ß2AR-cAMP response without altering the whole-cell L-type calcium current. Following local stimulation of Cav3DN-expressing ARVMs, ß2AR response could only be generated in T-tubules. However, the normally compartmentalized ß2AR-cAMP signal became diffuse, similar to the situation observed in heart failure. Finally, overexpression of Cav3 in failing myocytes led to partial ß2AR redistribution back into the T-tubules. In conclusion, Cav3 plays a crucial role for the localization of ß2AR and compartmentation of ß2AR-cAMP signaling to the T-tubules of healthy ARVMs, and overexpression of Cav3 in failing myocytes can partially restore the disrupted localization of these receptors.

Computational cardiology: how computer simulations could be used to develop new therapies and advance existing ones.

This article reviews the latest developments in computational cardiology. It focuses on the contribution of cardiac modelling to the development of new therapies as well as the advancement of existing ones for cardiac arrhythmias and pump dysfunction. Reviewed are cardiac modelling efforts aimed at advancing and optimizing existent therapies for cardiac disease (defibrillation, ablation of ventricular tachycardia, and cardiac resynchronization therapy) and at suggesting novel treatments, including novel molecular targets, as well as efforts to use cardiac models in stratification of patients likely to benefit from a given therapy, and the use of models in diagnostic procedures.