Complications Associated with Low Position versus Good Position Umbilical Venous Catheters in Neonates of ≤32 Weeks' Gestation.

Objective: This study aimed to determine the incidence of umbilical venous catheter associated infection (UVCAI) in very preterm infants based on UVC tip position.

Study Design: In this retrospective cohort study, infants born at ≤32 weeks were divided into groups with a UVC tip in either a low-lying or good position. The primary outcome was UVCAI.

Magnetic particles assisted capture and release of rare circulating tumor cells using wavy-herringbone structured microfluidic devices.

A wavy-herringbone (wavy-HB) structured microfluidic device was used to effectively and selectively capture and release circulating tumor cells (CTCs) by using immunoaffinity and magnetic force. This device was designed to create passive turbulence and increase the possibility of tumor cells colliding with the device wall. Under an external magnetic field, magnetic particles (MPs) coated with anti-EpCAM against a tumor cell surface protein (EpCAM) were immobilized over the wavy-HB surface to capture tumor cells.

Carbon Monoxide Poisoning: The Great Imitator.

Carbon Monoxide (CO) is one of the leading causes of poison deaths in the United States. Signs and symptoms are clinically variable secondary to inconsistent targeting of highly metabolic tissues by the gas. We report a case of a man in his early to mid-30's presenting to the emergency department with mental status changes, fatigue, headache, and flu-like symptoms for three days.

Iatrogenic Spinal Cord Injury in a Trauma Patient with Ankylosing Spondylitis.

Background: The recommended practice for over 30 years has been to routinely immobilize patients with unstable cervical spinal injuries using cervical spinal collars. It is shown that patients with Ankylosing spondylitis (AS) are four times more likely to suffer a spinal fracture compared to the general population and have an eleven-fold greater risk of spinal cord injury. Current protocols of spinal immobilization were responsible for secondary neurologic deterioration in some of these patients.

Cys palmitoylation of the beta subunit modulates gating of the epithelial sodium channel.

The epithelial Na(+) channel (ENaC) is comprised of three homologous subunits (α, β, and γ) that have a similar topology with two transmembrane domains, a large extracellular region, and cytoplasmic N and C termini. Although ENaC activity is regulated by a number of factors, palmitoylation of its cytoplasmic Cys residues has not been previously described. Fatty acid-exchange chemistry was used to determine whether channel subunits were Cys-palmitoylated.

Novel determinants of epithelial sodium channel gating within extracellular thumb domains.

Activity of the epithelial Na(+) channel (ENaC) is modulated by Na(+) self-inhibition, an allosteric down-regulation of channel open probability by extracellular Na(+). We searched for determinants of Na(+) self-inhibition by analyzing changes in this inhibitory response resulting from specific mutations within the extracellular domains of mouse ENaC subunits. Mutations at gammaMet(438) altered the Na(+) self-inhibition response in a substitution-specific manner.

Defining an inhibitory domain in the alpha-subunit of the epithelial sodium channel.

Epithelial sodium channels (ENaC) are processed by proteases as they transit the biosynthetic pathway. We recently observed that furin-dependent processing of the alpha-subunit of ENaC at two sites within its extracellular domain is required for channel activation due to release of a 26-residue inhibitory domain. While channels with alpha-subunits lacking the furin sites are not cleaved and have very low activity, channels lacking the furin consensus sites as well as the tract between these sites (alphaD206-R231) are active.

Epithelial sodium channel exit from the endoplasmic reticulum is regulated by a signal within the carboxyl cytoplasmic domain of the alpha subunit.

Epithelial sodium channels (ENaCs) are assembled in the endoplasmic reticulum (ER) from alpha, beta, and gamma subunits, each with two transmembrane domains, a large extracellular loop, and cytoplasmic amino and carboxyl termini. ENaC maturation involves transit through the Golgi complex where Asn-linked glycans are processed to complex type and the channel is activated by furin-dependent cleavage of the alpha and gamma subunits. To identify signals in ENaC for ER retention/retrieval or ER exit/release, chimera were prepared with the interleukin alpha subunit (Tac) and each of the three cytoplasmic carboxyl termini of mouse ENaC (Tac-Ct) or with gamma-glutamyltranspeptidase and each of the three cytoplasmic amino termini (Nt-GGT).

Functional role of extracellular loop cysteine residues of the epithelial Na+ channel in Na+ self-inhibition.

The epithelial Na(+) channel (ENaC) is typically formed by three homologous subunits (alpha, beta, and gamma) that possess a characteristic large extracellular loop (ECL) containing 16 conserved cysteine (Cys) residues. We investigated the functional role of these Cys residues in Na(+) self-inhibition, an allosteric inhibition of ENaC activity by extracellular Na(+). All 16 Cys residues within alpha and gamma ECLs and selected beta ECL Cys residues were individually mutated to alanine or serine residues.

Epithelial Na+ channels are fully activated by furin- and prostasin-dependent release of an inhibitory peptide from the gamma-subunit.

Epithelial sodium channels (ENaC) are expressed in the apical membrane of high resistance Na(+) transporting epithelia and have a key role in regulating extracellular fluid volume and the volume of airway surface liquids. Maturation and activation of ENaC subunits involves furin-dependent cleavage of the ectodomain at two sites in the alpha subunit and at a single site within the gamma subunit. We now report that the serine protease prostasin further activates ENaC by inducing cleavage of the gamma subunit at a site distal to the furin cleavage site.

Distinct structural elements in the first membrane-spanning segment of the epithelial sodium channel.

Epithelial Na+ channels (ENaCs) comprise three subunits that have been proposed to be arranged in either an alpha2betagamma or a higher ordered configuration. Each subunit has two putative membrane-spanning segments (M1 and M2), intracellular amino and carboxyl termini, and a large extracellular loop. We have used the TOXCAT assay (a reporter assay for transmembrane segment homodimerization) to identify residues within the transmembrane segments of ENaC that may participate in important structural interactions within ENaC, with which we identified a candidate site within alphaM1.