Ultrastructure and cardiac impulse propagation: scaling up from microscopic to macroscopic conduction.

The standard conception of cardiac conduction is based on the cable theory of nerve conduction, which treats cardiac tissue as a continuous syncytium described by the Hodgkin-Huxley equations. However, cardiac tissue is composed of discretized cells with microscopic and macroscopic heterogeneities and discontinuities, such as subcellular localizations of sodium channels and connexins. In addition to this, there are heterogeneities in the distribution of sympathetic and parasympathetic nerves, which powerfully regulate impulse propagation.

CALHM2 is a mitochondrial protein import channel that regulates fatty acid metabolism.

For mitochondrial metabolism to occur in the matrix, multiple proteins must be imported across the two (inner and outer) mitochondrial membranes. Classically, two protein import channels, TIM/TOM, are known to perform this function, but whether other protein import channels exist is not known. Here, using super-resolution microscopy, proteomics, and electrophysiological techniques, we identify CALHM2 as the import channel for the ECHA subunit of the mitochondrial trifunctional protein (mTFP), which catalyzes β-oxidation of fatty acids in the mitochondrial matrix.

Historic obstacles and emerging opportunities in the field of developmental metabolism - lessons from Heidelberg.

The field of developmental metabolism is experiencing a technological revolution that is opening entirely new fields of inquiry. Advances in metabolomics, small-molecule sensors, single-cell RNA sequencing and computational modeling present new opportunities for exploring cell-specific and tissue-specific metabolic networks, interorgan metabolic communication, and gene-by-metabolite interactions in time and space. Together, these advances not only present a means by which developmental biologists can tackle questions that have challenged the field for centuries, but also present young scientists with opportunities to define new areas of inquiry.

Cerebrospinal fluid flushing as a means of neuroprotection.

Central nervous system (CNS) injury or disease states are often difficult to treat due to the closed system of the dura mater/blood-brain barrier and the bony skull and vertebrae. The closed system results in at least partial containment of any pro-inflammatory molecules, pathogens, or toxic byproducts in the case of brain or spinal cord lesions, which can result in a destructive feedback loop. Cervical-approach access techniques (lateral C1-C2, suboccipital and lateral atlanto-occipital space punctures) are less-common methods of cerebrospinal fluid (CSF) sampling due to the relative ease and safety of lumbar spinal taps.

Impact of COVID-19 pandemic on pharmacologic treatment of patients newly diagnosed with osteoporosis.

Purpose: This study determined whether initiation of pharmacologic treatment was delayed for newly diagnosed osteoporosis patients during the COVID-19 pandemic.

Methods: 1,189 patients ≥50 years with newly diagnosed osteoporosis using dual-energy x-ray absorptiometry (DXA) screening at a single academic institution were included. Patients with previous osteoporosis were excluded.