2024 Australia-New Zealand Expert Consensus Statement on Cardiac Amyloidosis.

Over the past 5 years, early diagnosis of and new treatments for cardiac amyloidosis (CA) have emerged that hold promise for early intervention. These include non-invasive diagnostic tests and disease modifying therapies. Recently, CA has been one of the first types of cardiomyopathy to be treated with gene editing techniques. Although these therapies are not yet widely available to patients in Australia and New Zealand, this may change in the near future. Given the rapid pace with which this field is evolving, it is important to view these advances within the Australian and New Zealand context. This Consensus Statement aims to update the Australian and New Zealand general physician and cardiologist with regards to the diagnosis, investigations, and management of CA.

Validation of the "Doorbell Test": A Novel Functional Test of Frailty and Clinical Status After Acute Decompensated Heart Failure.

BACKGROUND: Acute decompensated heart failure (ADHF) carries a high event rate following discharge. The complex interplay between age, frailty and decongestion may lend itself to a functional test. METHODS: In the doorbell test the patient simulates answering the doorbell. They are timed rising from a recumbent position, bending over twice and walking 10 metres, this time is added to the change in respiratory rate. We aimed to determine if the doorbell test was associated with post ADHF events (death or readmission). The test was performed at hospital discharge, with follow up at 30-days and 1-year. RESULTS: In 74 patients at 30-days there was a 14% event rate. At 1-year there were 40 (54%) events (9 deaths and 31 readmissions, 28 were cardiovascular of which 14 were [heart failure] HF). Amongst those who had an event at 30-days only doorbell test scores were different (58 [36,72] vs 32 [26,53] p < 0.05). One-year (1-year) events were associated with doorbell test scores (47 [29,62] vs 30 [26,42] p < 0.05), body weight (78 kg [68,94] vs 95 [76,105] (p < 0.05), creatinine (134 mmol/L [114, 173] vs 99 [82, 133] p < 0.01) and age (76 years [61,86] vs 67 [53, 73] p < 0.01). Heart failure readmissions were associated with doorbell test scores (56 [46,68] vs 30 [26,47] p < 0.001). Death was associated with body weight (74 kg [69,81] vs 88 [72,101] p < 0.05) and age (83 years [78,86] vs 69 [55,77] p < 0.01). After age stratification, the hazard ratio for heart failure readmission associated with a high doorbell test score was 11.08 (95%C.I. 2.01-61.17 p = 0.006), while the hazard ratio for 1-year cardiovascular readmission was 4.62 (95%C.I. 1.71-12.51 p = 0.003). There was no association with 1-year mortality. CONCLUSION: The doorbell test represents a novel test of multiple domains of the ADHF pre-discharge state and demonstrates an association with 30-day and 1-year rehospitalisation.

Selective encapsulation by Janus particles.

We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored, as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.

Euglycemic Ketoacidosis in Two Patients Without Diabetes After Introduction of Sodium-Glucose Cotransporter 2 Inhibitor for Heart Failure With Reduced Ejection Fraction.

OBJECTIVE: Ketoacidosis induced by sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment has been consistently observed in clinical practice in patients with type 2 diabetes despite minimal indication from the landmark cardiovascular outcome trials. It has been postulated that individuals without diabetes will not develop this complication due to an adequate insulin secretory capacity, which will protect against significant ketone formation. Cardiovascular outcome trials examining SGLT2i use in individuals with heart failure but not diabetes have not reported ketoacidosis. RESEARCH DESIGN AND METHODS: We describe the first two case reports of severe nondiabetic ketoacidosis after initiation of an SGLT2i for the treatment of heart failure with reduced ejection fraction, and we describe the management strategies employed and implication for the pathophysiology of SGLT2i-associated ketoacidosis. RESULTS: Each individual presented with ketoacidosis triggered by reduced oral nutrition intake. For both individuals, ketoacidosis resolved with intravenous glucose administration, encouragement of consumption of oral glucose-containing fluid, and minimal insulin administration. CONCLUSIONS: These two cases demonstrate that SGLT2i-associated ketoacidosis is possible in individuals without diabetes.

Self-assembly of Janus ellipsoids II: Janus prolate spheroids.

In self-assembly, the anisotropy of the building blocks and their formation of complex structures have been the subject of considerable recent research. Extending recent research on Janus particles and completing the study of Janus spheroids, we conduct a systematic investigation on the self-assembly of Janus prolate spheroids based on a primitive model that we proposed. Janus prolate spheroids are particles that have a prolate spheroidal body and two hemi-surfaces along the major axis coded with different chemical properties. Using Monte Carlo simulations, we investigate the effects of the aspect ratio on the self-assembly process. In contrast to the vesicle-like aggregates for Janus oblate spheroids, we obtain various ordered cluster structures for Janus prolate spheroids through self-assembly. With an increasing aspect ratio, we find a transition of cluster morphology, from vesicles to tubular micelles and micelles. In particular, a relatively small change in the aspect ratio leads to a rather significant change in morphology. We apply a cluster analysis to understand the mechanism associated with such a transition.

Self-assembly of a bipolar model of biomacromolecules.

Extending recent work on a generic bipolar model proposed to study the nanochain formation of amelogenin molecules, we conduct a systematic investigation in this paper on the self-assembly of such a model via sweeping the relative parameter space. The bipolar model consists of a short-range attraction and an off-center Coulomb repulsion for the supermolecule. Through the Brownian dynamics simulation of both translational and rotational motions, we study the kinetics of the self-assembly and the structure of clusters formed within the system for various interaction settings. From the results of structure factor and cluster analysis, we find that the range of the repulsive interaction has a sensitive impact in controlling the cluster size, while the strength of the attractive interaction dominates the cluster morphology such that the greater the attraction among particles, the more elongated the cluster formed.

Self assembly of Janus ellipsoids.

We propose a primitive model of Janus ellipsoids that represents particles with an ellipsoidal core and two semisurfaces coded with dissimilar properties, for example, hydrophobicity and hydrophilicity, respectively. We investigate the effects of the aspect ratio on the self-assembly morphology and aggregation processes using Monte Carlo simulations. We also discuss certain differences between our results and those of earlier results for Janus spheres. In particular, we find that the size and structure of the aggregate can be controlled by the aspect ratio.

Effect of solvent on the phase diagram of a simple anisotropic model of globular proteins.

Anisotropic protein interactions play a role in globular protein phase transitions, including the shape of fluid-fluid coexistence curves and the formation of hemoglobin polymer fibers in sickle cell disease. Also, the solvent has been shown to play an important role in the phase behavior of some aqueous protein solutions, through the release or trapping of water molecules upon crystallization. Both anisotropy and solvent effects have been treated separately in earlier theoretical studies. Here we propose and analyze a simple, composite model that treats both anisotropy and solvent effects. We find that this model qualitatively explains some phase behavior that has been observed in protein solutions, including normal and retrograde solubility curves and lower critical points.

Impact of Late Gadolinium Enhancement on mortality, sudden death and major adverse cardiovascular events in ischemic and nonischemic cardiomyopathy: A systematic review and meta-analysis.

BACKGROUND: The central role of left ventricular ejection fraction (LVEF) as the definitive risk marker of adverse outcomes in ischemic and nonischemic cardiomyopathy is increasingly uncertain. The current study aimed to conduct a systematic review and meta-analysis with the objective of evaluating the prognostic importance of Late Gadolinium Enhancement (LGE) in ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) on the key endpoints of all-cause mortality, cardiovascular mortality and sudden death. METHODS: The study was prospectively registered in PROPSERO (CRD 42016039034). Electronic databases and reference lists were searched for studies evaluating the impact of LGE-CMR on all-cause mortality, cardiovascular mortality, ventricular arrhythmia or sudden death, or major adverse cardiovascular events. Data were extracted from 36 studies including n=7882 patients. RESULTS: LGE was strongly associated with all-cause mortality HR 2.96 (95%CI: 2.37, 3.70, P<0.001), cardiovascular mortality HR 3.27 (95% CI: 2.05, 5.22, P<0.001), ventricular arrhythmia and sudden cardiac death HR 3.76 (95% CI: 3.14, 4.52, P<0.001), and major adverse cardiovascular events HR 3.24 (95% CI: 2.32, 4.52, P<0.001). In subgroup analyses, LGE was associated with all-cause mortality and cardiovascular mortality in both LVEF≤35% and LVEF>35% patients (P<0.001 all endpoints), as well as in nonischemic and ischemic cardiomyopathy. CONCLUSION: Late Gadolinium Enhancement (LGE) in CMR predicts all-cause mortality, cardiovascular mortality, ventricular arrhythmia and sudden death, and major adverse cardiovascular events, independent of LVEF. Future trials of investigational therapies in NICM and ICM should consider the utilization of LGE to identify patients at risk of adverse outcomes.

Liquid-liquid coexistence surface for lysozyme: role of salt type and salt concentration.

The liquid-liquid phase separation curves for lysozyme in a salt solution are known to depend on salt type and salt concentration. For the case of monovalent cations, the cloud point temperature typically increases with increasing salt concentration, for fixed lysozyme concentration. For the case of divalent cations, however, a maximum in the cloud point temperature is observed that has been interpreted as being due to ion binding to the protein surface and subsequent water structuring. In this paper, we use a simple square well model due to Grigsby et al. (Biophys. Chem. 2001, 91, 231-243), whose well depth depends on salt type and salt concentration, to determine the phase coexistence surfaces from experimental data. The surfaces are shown as a function of temperature, salt concentration, and protein concentration for two typical salts, NaCl and MgCl2. These surfaces are calculated using the results of a single standard Monte Carlo simulation and a simple scaling argument and are in reasonably good agreement with known experimental results.

P2Y12 Inhibitor Pre-Treatment in Non-ST-Elevation Acute Coronary Syndrome: A Decision-Analytic Model.

Current guidelines recommend initiation of a P2Y12 inhibitor for all patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) at the time of diagnosis (pre-treatment); however, there are no randomized trials directly comparing pre-treatment with initiation at the time of angiography to support this practice. We explore clinical and institutional parameters potentially associated with benefit with this strategy in a decision-analytic model based on available evidence from randomised trials. A decision analysis model was constructed comparing three P2Y12 inhibitors in addition to aspirin in patients with NSTE-ACS. Based on clinical trial data, the cumulative probability of 30 day mortality, myocardial infarction (MI) and major bleeding were determined, and used to calculate the net clinical benefit (NCB) with and without pre-treatment. Sensitivity analysis was performed to assess the relationship between NCB and baseline ischemic risk, bleeding risk, time to angiography and local surgical revascularization rates. Pre-treatment with ticagrelor and clopidogrel was associated with a greater than 50% likelihood of providing a >1% increase in 30 day NCB when baseline estimated ischemic risk exceeds 11% and 14%, respectively. Prasugrel pre-treatment did not achieve a greater than 50% probability of an increase in NCB regardless of baseline ischemic risk. Institutional surgical revascularization rates and time to coronary angiography did not correlate with the likelihood of benefit from P2Y12 pre-treatment. In conclusion, pre-treatment with P2Y12 inhibition is unlikely to be beneficial to the majority of patients presenting with NSTE-ACS. A tailored assessment of each patient's individual ischemic and bleeding risk may identify those likely to benefit.

The constructive role of diversity in the global response of coupled neuron systems.

We study the effect that the heterogeneity present among the elements of an ensemble of coupled excitable neurons has on the collective response of the system to an external signal. We consider two different interaction scenarios, one in which the neurons are diffusively coupled and another in which the neurons interact via pulse-like signals. We find that the type of interaction between the neurons has a crucial role in determining the response of the system to the external modulation. We develop a mean-field theory based on an order parameter expansion that quantitatively reproduces the numerical results in the case of diffusive coupling.

Entry exclusion in the IncHI1 plasmid R27 is mediated by EexA and EexB.

Conjugative plasmids have evolved entry exclusion mechanisms to inhibit redundant DNA transfer from donor cells into recipients harboring isogenic or closely related plasmids. This exclusion phenomenon has been documented in the incompatibility H group (IncH) plasmid R27. A cosmid library representing the majority of the large (180kb) R27 plasmid was transformed into recipient cells and a conjugation assay identified that an operon located in the conjugative transfer region 2 (Tra2) of R27, the Z operon, mediated entry exclusion in the IncH plasmid. Reverse-transcriptase analysis revealed that the Z operon is comprised of four genes, 015, eexB, 017, and eexA. Sub-cloning of the individual genes located within the Z operon and subsequent screening for the entry exclusion phenotype determined that two genes, eexA and eexB, independently inhibit the entry of IncH-related plasmids. Bacterial fractionation studies predominantly localized the EexA protein to the cytoplasmic membrane, and the EexB protein to the outer membrane. Recipient cells expressing EexA and EexB were unable to exclude the entry of R27 plasmids harboring mutations within the IncH entry exclusion genes eexA and eexB. The IncH entry exclusion proteins EexA and EexB likely prevent redundant plasmid transfer by interaction with one another.

Interaction between the co-inherited TraG coupling protein and the TraJ membrane-associated protein of the H-plasmid conjugative DNA transfer system resembles chromosomal DNA translocases.

Bacterial conjugation is a DNA transfer event that requires three plasmid-encoded multi-protein complexes: the membrane-spanning mating pair formation (Mpf) complex, the cytoplasmic nucleoprotein relaxosome complex, and a homo-multimeric coupling protein that links the Mpf and relaxosome at the cytoplasmic membrane. Bacterial two-hybrid (BTH) technology and immunoprecipitation were used to demonstrate an interaction between the IncH plasmid-encoded transfer protein TraJ and the coupling protein TraG. TraJ is essential for conjugative transfer but is not required for the formation of the conjugative pilus, and is therefore not regarded as an Mpf component. Fractionation studies indicated that TraJ shared a similar cellular domain to that of TraG at the cellular membrane. Protein blast analyses have previously identified TraJ homologues encoded in a multitude of plasmid and chromosomal genomes that were also found to encode an adjacent TraG homologue, thus indicating co-inheritance. BTH analysis of these TraJ and cognate TraG homologues demonstrated conservation of the TraJ-TraG interaction. Additional occurrences of the traJ-traG module were also detected in genomic sequence data throughout the Proteobacteria, and phylogenetic comparison of these IncH-like TraG proteins with the coupling proteins encoded by other conjugative transfer systems (including IncP, IncW and IncF) that lack TraJ homologues indicated that the H-like coupling proteins were distinct. Accordingly, the IncP, IncW and IncF coupling proteins were unable to interact with TraJ, but were able to interact with IncH plasmid-encoded TrhB, an Mpf component known to complex with its cognate coupling protein TraG. The divergence of the IncH-type coupling proteins may partly be due to the requirement of TraJ interaction, and notably, TraG and TraJ cumulatively represent the domain architecture of the known translocase family FtsK/SpoIIIE. It is proposed that TraJ is a functional part of the IncH-type coupling protein complex required for translocation of DNA through the cytoplasmic membrane.

Diversity-induced resonance.

We present conclusive evidence showing that different sources of diversity, such as those represented by quenched disorder or noise, can induce a resonant collective behavior in an ensemble of coupled bistable or excitable systems. Our analytical and numerical results show that when such systems are subjected to an external subthreshold signal, their response is optimized for an intermediate value of the diversity. These findings show that intrinsic diversity might have a constructive role and suggest that natural systems might profit from their diversity in order to optimize the response to an external stimulus.

Role of solvent for globular proteins in solution.

The properties of the solvent affect the behavior of the solution. We propose a model that accounts for the contribution of the solvent free energy to the free energy of globular proteins in solution. For the case of an attractive square-well potential, we obtain an exact mapping of the phase diagram of this model without solvent to the model that includes the solute-solvent contribution. In particular we find for appropriate choices of parameters upper critical points, lower critical points, and even closed loops with both upper and lower critical points similar to those found before [Macromolecules 36, 5843 (2003)]. In the general case of systems whose interactions are not attractive square wells, this mapping procedure can be a first approximation to understand the phase diagram in the presence of solvent. We also present simulation results for both the square-well model and a modified Lennard-Jones model.

Subcellular localization and functional domains of the coupling protein, TraG, from IncHI1 plasmid R27.

Bacterial conjugation is a horizontal gene transfer event mediated by the type IV secretion system (T4SS) encoded by bacterial plasmids. Within the T4SS, the coupling protein plays an essential role in linking the membrane-associated pore-forming proteins to the cytoplasmic, DNA-processing proteins. TraG is the coupling protein encoded by the incompatibility group HI plasmids. A hallmark feature of the IncHI plasmids is optimal conjugative transfer at 30 degrees C and an inability to transfer at 37 degrees C. Transcriptional analysis of the transfer region 1 (Tra1) of R27 has revealed that traG is transcribed in a temperature-dependent manner, with significantly reduced levels of expression at 37 degrees C as compared to expression at 30 degrees C. The R27 coupling protein contains nucleoside triphosphate (NTP)-binding domains, the Walker A and Walker B boxes, which are well conserved among this family of proteins. Site-specific mutagenesis within these motifs abrogated the conjugative transfer of R27 into recipient cells. Mutational analysis of the TraG periplasmic-spanning residues, in conjunction with bacterial two-hybrid and immunoprecipitation analysis, determined that this region is essential for a successful interaction with the T4SS protein TrhB. Further characterization of TraG by immunofluorescence studies revealed that the R27 coupling protein forms membrane-associated fluorescent foci independent of R27 conjugative proteins. These foci were found at discrete positions within the cell periphery. These results allow the definition of domains within TraG that are involved in conjugative transfer, and determination of the cellular location of the R27 coupling protein.

Crystal nucleation for a model of globular proteins.

A continuum model of globular proteins proposed by Talanquer and Oxtoby [J. Chem. Phys. 109, 223 (1998)] is investigated numerically, with particular emphasis on the region near the metastable fluid-fluid coexistence curve. Classical nucleation theory is shown to be invalid not only in the vicinity of the metastable critical point but also close to the liquidus line. An approximate analytic solution is also presented for the shape and properties of the nucleating crystal droplet.

Interaction between the IncHI1 plasmid R27 coupling protein and type IV secretion system: TraG associates with the coiled-coil mating pair formation protein TrhB.

Assemblies of plasmid-encoded proteins direct the conjugative transfer of plasmid DNA molecules between bacteria. These include the membrane-associated mating pair formation (Mpf) complex necessary for pilus production and the cytoplasmic relaxosome required for DNA processing. The proposed link between these distinct protein complexes is the coupling protein (the TraG family of proteins). Interactions between the coupling protein and relaxosome components have been previously characterized and we document here, for the first time, a direct interaction between the coupling protein and an Mpf protein. Using the adenylate cyclase bacterial two-hybrid (BTH) system, we present in vivo evidence that the IncHI1 plasmid R27-encoded proteins TraG and TrhB interact. This interaction was verified through a co-immunoprecipitation reaction. We have also been able to delineate the interaction domain of TrhB to TraG by showing a positive interaction using the first 220 amino acids of TrhB (452 aa). TrhB has a proline-rich domain from amino acids 135-173 which may serve to facilitate protein interactions and/or periplasmic extension. TrhB self association was detected using far-Western, co-immunoprecipitation, and also BTH analysis, which was used to define the homotypic interaction domain, comprising a predicted coiled-coil region at residues 77-124 of TrhB. These data support a model in which the coupling protein interacts with an Mpf component to target the transferring DNA strand held by the relaxosome to the transmembrane Mpf complex.

Functional and mutational analysis of conjugative transfer region 2 (Tra2) from the IncHI1 plasmid R27.

The transfer 2 region (Tra2) of the conjugative plasmid drR27 (derepressed R27) was analyzed by PSI-BLAST, insertional mutagenesis, genetic complementation, and an H-pilus assay. Tra2 contains 11 mating-pair formation (Mpf) genes that are essential for conjugative transfer, 9 of which are essential for H-pilus production (trhA, -L, -E, -K, -B, -V, -C, -P, and -W). TrhK has similarity to secretin proteins, suggesting a mechanism by which DNA could traverse the outer membrane of donors. The remaining two Mpf genes, trhU and trhN, play an auxiliary role in H-pilus synthesis and are proposed to be involved in DNA transfer and mating-pair stabilization, respectively. Conjugative transfer abilities were restored for each mutant when complemented with the corresponding transfer gene. In addition to the essential Mpf genes, three genes, trhO, trhZ, and htdA, modulate R27 transfer frequency. Disruption of trhO and trhZ severely reduced the transfer frequencies of drR27, whereas disruption of htdA greatly increased the transfer frequency of wild-type R27 to drR27 levels. A comparison of the essential transfer genes encoded by the Tra2 and Tra1 (T. D. Lawley, M. W. Gilmour, J. E. Gunton, L. J. Standeven, and D. E. Taylor, J. Bacteriol. 184:2173-2183, 2002) of R27 to other transfer systems illustrates that the R27 conjugative transfer system is a chimera composed of IncF-like and IncP-like transfer systems. Furthermore, the Mpf/type IV secretion systems encoded by IncH and IncF transfer systems are distinct from that of the IncP transfer system. The phenotypic and ecological significance of these observations is discussed.