Radiation induces diffuse extracellular remodeling of healthy myocardium in a dose- and time-dependent manner without a dense ablative effect.

Background: Although early studies of cardiac stereotactic body radiotherapy (cSBRT) show promise as a therapy to treat drug-refractory ventricular tachycardia, there remain knowledge gaps in its application, including the ideal doses to apply, which radiation source to use, which substrates to target, and the structural and electrophysiological effects seen after cSBRT.

Objective: Here, we examine doses up to 50 Gy to assess lesion formation by longitudinally following healthy myocardium after photon radiation using cardiac magnetic resonance (CMR) imaging and correlating those findings with histologic analysis.

Methods: Eight healthy canines underwent stereotactic photon beam cSBRT targeting healthy cardiac tissue.

Association Between Family History and Early-Onset Atrial Flutter Across Racial and Ethnic Groups.

Background: Genetic and familial contributions to early-onset atrial fibrillation are described primarily in individuals of European ancestry. However, the role of racial and familial contributions in the pathogenesis of early-onset atrial flutter (EOAFL) is unclear.

Methods And Results: In this cross-sectional study, participants were enrolled prospectively from 2015 to 2021 in multiple academic centers with a diagnosis of atrial flutter (AFL) confirmed by ECG.

DNA metabarcoding reveals high relative abundance of trunk disease fungi in grapevines from Marlborough, New Zealand.

Grapevine trunk diseases (GTDs) are a threat to grape production worldwide, with a diverse collection of fungal species implicated in disease onset. Due to the long-term and complex nature of GTDs, simultaneous detection of multiple microbial species can enhance understanding of disease development. We used DNA metabarcoding of ribosomal internal transcribed spacer 1 (ITS1) sequences, supported by specific PCR and microbial isolation, to establish the presence of trunk pathogens across 11 vineyards (11-26 years old) over three years in Marlborough, the largest wine producing region in New Zealand.

High throughput pH bioassay demonstrates pH adaptation of Rhizobium strains isolated from the nodules of Trifolium subterraneum and T. repens.

The purpose of developing this high throughput assay was to determine whether there was evidence of pH adaptation in strains of rhizobia which nodulate subterranean clover (SC) and white clover (WC), and whether this was related to the pH of the soil of origin. pH is a first-order factor influencing the niche preferences of soil microorganisms and has been convincingly shown to be a key driver of soil bacterial communities. Naturalised strains of Rhizobium spp.

Association of Psychosocial Factors With Short-Term Resting Heart Rate Variability: The Atherosclerosis Risk in Communities Study.

Background Psychosocial factors predict heart disease risk, but our understanding of underlying mechanisms is limited. We sought to evaluate the physiologic correlates of psychosocial factors by measuring their relationships with heart rate variability (HRV), a measure of autonomic health, in the ARIC (Atherosclerosis Risk in Communities) study. We hypothesize that increased psychosocial stress associates with lower HRV.

Alterations in heart rate variability are associated with abnormal myocardial perfusion.

Background: Abnormalities in the autonomic nervous system may occur in ischemic heart disease, but the mechanisms by which they are linked are not fully defined. The risk of cardiac events is increased during morning hours. Studying the contributions of autonomic mechanisms may yield insights into risk stratification and treatment.