Single-Molecule Approaches to Study DNA Condensation.

Proteins drive genome compartmentalization across different length scales. While the identities of these proteins have been well-studied, the physical mechanisms that drive genome organization have remained largely elusive. Studying these mechanisms is challenging owing to a lack of methodologies to parametrize physical models in cellular contexts.

PARP1-DNA co-condensation drives DNA repair site assembly to prevent disjunction of broken DNA ends.

DNA double-strand breaks (DSBs) are repaired at DSB sites. How DSB sites assemble and how broken DNA is prevented from separating is not understood. Here we uncover that the synapsis of broken DNA is mediated by the DSB sensor protein poly(ADP-ribose) (PAR) polymerase 1 (PARP1).

Rising abuse of veterinary drugs.

There has been a significant increase in veterinary drugs found on toxicology screens and postmortem analyses, especially in the Northeast region of the US. This article details the effects and treatment of two common culprits: xylazine and tiletamine-zolazepam.

Cohesin and condensin extrude DNA loops in a cell cycle-dependent manner.

Loop extrusion by structural maintenance of chromosomes (SMC) complexes has been proposed as a mechanism to organize chromatin in interphase and metaphase. However, the requirements for chromatin organization in these cell cycle phases are different, and it is unknown whether loop extrusion dynamics and the complexes that extrude DNA also differ. Here, we used egg extracts to reconstitute and image loop extrusion of single DNA molecules during the cell cycle.

Nicotine toxicity: Protecting children from e-cigarette exposure.

Compared with children exposed to traditional cigarettes, those exposed to nicotine in e-cigarettes are 5.2 times more likely to be admitted to a healthcare facility and have 2.6 times the risk of a severe outcome.

Considering toxicology: Specialists in poison information.

Toxicology is an interesting and specialized branch of medicine. This article examines the parallels between nursing and working as a specialist in poison information, offering a different career path for eligible nurses.

Overview of Silica-Related Clusters in the United States: Will Fracking Operations Become the Next Cluster?

Silicosis is the oldest know occupational pulmonary disease. It is a progressive disease and any level of exposure to respirable crystalline silica particles or dust has the potential to develop into silicosis. Silicosis is caused by silica particles or dust entering the lungs and damaging healthy lung tissue.

Predicting the onset of period-doubling bifurcations in noisy cardiac systems.

Biological, physical, and social systems often display qualitative changes in dynamics. Developing early warning signals to predict the onset of these transitions is an important goal. The current work is motivated by transitions of cardiac rhythms, where the appearance of alternating features in the timing of cardiac events is often a precursor to the initiation of serious cardiac arrhythmias.

Computational study of synchrony in fields and microclusters of ephaptically coupled neurons.

Neuronal hypersynchrony is implicated in epilepsy and other diseases. The low-frequency, spatially averaged electric fields from many thousands of neurons have been shown to promote synchrony. It remains unclear whether highly transient, spatially localized electric fields from single action potentials (ephaptic coupling) significantly affect spike timing of neighboring cells and in consequence, population synchrony.

Technology in health care: forensic implications.

Technology continues to evolve and improve making our everyday tasks appear sometimes routine and mundane. The health care industry has embraced technological advances to improve on its daily operations in an effort to run more efficiently. Health care providers must be aware that these technologies collect data, lots of data, which is discoverable and may be used to defend or refute your actions as a nurse.

Spatial symmetry breaking determines spiral wave chirality.

Chirality represents a fundamental property of spiral waves. Introducing obstacles into cardiac monolayers leads to the initiation of clockwise-rotating, counterclockwise-rotating, and pairs of spiral waves. Simulations show that the precise location of the obstacle and the pacing frequency determine spiral wave chirality.

Prekallikrein deficiency.

Nurses often encounter abnormal laboratory assays that require them to investigate further to ensure that appropriate patient care is provided. A prolonged activated partial thromboplastin time (PTT) with a normal prothrombin time (PT) assay demand further examination, to rule out laboratory error or bleeding disorders. Prekallikrein deficiency is a rare coagulation deficiency that presents itself with a prolonged PTT and a normal PT.

Vitamin D receptor as a master regulator of the c-MYC/MXD1 network.

Vitamin D signaling regulates cell proliferation and differentiation, and epidemiological data suggest that it functions as a cancer chemopreventive agent, although the underlying mechanisms are poorly understood. Vitamin D signaling can suppress expression of genes regulated by c-MYC, a transcription factor that controls epidermal differentiation and cell proliferation and whose activity is frequently elevated in cancer. We show through cell- and animal-based studies and mathematical modeling that hormonal 1,25-dihydroxyvitamin D (1,25D) and the vitamin D receptor (VDR) profoundly alter, through multiple mechanisms, the balance in function of c-MYC and its antagonist the transcriptional repressor MAD1/MXD1.

Chaotic dynamics in cardiac aggregates induced by potassium channel block.

Chaotic rhythms in deterministic models can arise as a consequence of changes in model parameters. We carried out experimental studies in which we induced a variety of complex rhythms in aggregates of embryonic chick cardiac cells using E-4031 (1.0-2.

Tunable oscillations and chaotic dynamics in systems with localized synthesis.

Biological systems contain biochemical control networks that reside within a remarkable spatial structure. We present a theoretical study of a biological system in which two chemically coupled species, an activating species and an inhibiting species forming a negative feedback, are synthesized at unique sites and interact with each other through diffusion. The dynamical behaviors in these systems depend on the spatial locations of these synthetic sites.