Lung transplant referral considerations for individuals with cystic fibrosis.

Purpose Of Review: The cystic fibrosis (CF) Foundation issued guidelines to promote timely lung transplant referral for people with cystic fibrosis (pwCF) in 2019. Since then more has been published to help refine this complex decision. The goal of this review is to summarize the recent literature informing disease severity in CF, barriers to referral for pwCF and guide timely and appropriate lung transplant referrals.

DNA methylation as a transcriptional regulator of the immune system.

DNA methylation is a dynamic epigenetic modification with a prominent role in determining mammalian cell development, lineage identity, and transcriptional regulation. Primarily linked to gene silencing, novel technologies have expanded the ability to measure DNA methylation on a genome-wide scale and uncover context-dependent regulatory roles. The immune system is a prototypic model for studying how DNA methylation patterning modulates cell type- and stimulus-specific transcriptional programs.

Predictors of improved functional outcome following inpatient rehabilitation for patients with traumatic brain injury.

Objective: To determine factors associated with response to inpatient rehabilitation treatment among TBI patients.

Setting: Inpatient rehabilitation service at a Level I trauma center.

Participants: Moderate-severe TBI patients ages ≥ 18years old admitted between January 1, 2002 and December 31, 2012.

Charge site mass spectra: conformation-sensitive components of the electron capture dissociation spectrum of a protein.

A conventional electron capture dissociation (ECD) spectrum of a protein is uniquely characteristic of the first dimension of its linear structure. This sequence information is indicated by summing the primary c (m+) and z (m+•) products of cleavage at each of its molecular ion's inter-residue bonds. For example, the ECD spectra of ubiquitin (M + nH)(n+) ions, n = 7-13, provide sequence characterization of 72 of its 75 cleavage sites from 1843 ions in seven c ((1-7)+) and eight z ((1-8)+•) spectra and their respective complements.

Thiamin biosynthesis: still yielding fascinating biological chemistry.

The present paper describes the biosynthesis of the thiamin thiazole in Bacillus subtilis and Saccharomyces cerevisiae. The two pathways are quite different: in B. subtilis, the thiazole is formed by an oxidative condensation of glycine, deoxy-D-xylulose 5-phosphate and a protein thiocarboxylate, whereas, in S.

How ubiquitin unfolds after transfer into the gas phase.

The structural evolution of ubiquitin after transfer into the gas phase was studied by electron capture dissociation. Site-specific fragment yields show that ubiquitin's solution fold is overall unstable in the gas phase, but unfolding caused by loss of solvent is slowest in regions stabilized by salt bridges.

A century of progress in molecular mass spectrometry.

The first mass spectrum of a molecule was measured by J.J. Thomson in 1910.

Chemokine CXC receptor 4--mediated glioma tumor tracking by bone marrow--derived neural progenitor/stem cells.

Malignant gliomas manifest frequent tumor recurrence after surgical resection and/or other treatment because of their nature of invasiveness and dissemination. The recognized brain tumor-tracking property of neural progenitor/stem cells opened the possibility of targeting malignant brain tumors using neural progenitor/stem cells. We and others have previously shown that fetal neural progenitor/stem cells can be used to deliver therapeutic molecules to brain tumors.

IgE receptor-mediated alteration of membrane-cytoskeleton interactions revealed by mass spectrometric analysis of detergent-resistant membranes.

We use electrospray ionization mass spectrometry to quantify >100 phospholipid (PL) components in detergent-resistant membrane (DRM) domains that are related to ordered membrane compartments commonly known as lipid rafts. We previously compared PL compositions of DRMs with plasma membrane vesicles and whole cell lipid extracts from RBL mast cells, and we made the initial observation that antigen stimulation of IgE receptors (FcepsilonRI) causes a significant change in the PL composition of DRMs [Fridriksson, E. K.

Preparation and characterization of antioxidant nanospheres from multiple alpha-lipoic acid-containing compounds.

The purpose of this study was to prepare and characterize antioxidant nanospheres composed of multiple alpha-lipoic acid-containing compounds (mALAs). It was found that the nanospheres were remarkably stable under physiologic conditions, maintained the antioxidant property of alpha-lipoic acid, and could be destabilized oxidatively and enzymatically. The preparations were simple and highly reproducible providing a new strategy for the development of nanometer-sized antioxidant biomaterials.

Stimuli-responsive antioxidant nanoprodrugs of NSAIDs.

A novel group of alpha-lipoic acid-containing hydrophobic prodrugs of non-steroidal anti-inflammatory drugs (NSAIDs) was synthesized and transformed into nanometer-sized prodrugs (nanoprodrugs). Three NSAIDs, indomethacin, ibuprofen and naproxen were linked to alpha-lipoic acid via tetraethylene glycol through hydrolytically degradable ester bonds. The three bifunctional derivatives were dissolved in organic solvents and capable of forming stable nanoprodrugs upon addition of the organic solutions into aqueous phase through the spontaneous emulsification mechanism.

Stepwise evolution of protein native structure with electrospray into the gas phase, 10(-12) to 10(2) s.

Mass spectrometry (MS) has been revolutionized by electrospray ionization (ESI), which is sufficiently "gentle" to introduce nonvolatile biomolecules such as proteins and nucleic acids (RNA or DNA) into the gas phase without breaking covalent bonds. Although in some cases noncovalent bonding can be maintained sufficiently for ESI/MS characterization of the solution structure of large protein complexes and native enzyme/substrate binding, the new gaseous environment can ultimately cause dramatic structural alterations. The temporal (picoseconds to minutes) evolution of native protein structure during and after transfer into the gas phase, as proposed here based on a variety of studies, can involve side-chain collapse, unfolding, and refolding into new, non-native structures.

Early structural evolution of native cytochrome c after solvent removal.

Electrospray ionization transfers thermally labile biomolecules, such as proteins, from solution into the gas phase, where they can be studied by mass spectrometry. Covalent bonds are generally preserved during and after the phase transition, but it is less clear to what extent noncovalent interactions are affected by the new gaseous environment. Here, we present atomic-level computational data on the structural rearrangement of native cytochrome c immediately after solvent removal.

Top-down identification and characterization of biomolecules by mass spectrometry.

The most widely used modern mass spectrometers face severe performance limitations with molecules larger than a few kDa. For far larger biomolecules, a common practice has been to break these up chemically or enzymatically into fragments that are sufficiently small for the instrumentation available. With its many sophisticated recent enhancements, this "bottom-up" approach has proved highly valuable, such as for the rapid, routine identification and quantitation of DNA-predicted proteins in complex mixtures.

Detecting native folds in mixtures of proteins that contain disulfide bonds.

High-throughput in vitro refolding of proteins that contain disulfide bonds, for which soluble expression is particularly difficult, is severely impeded by the absence of effective methods for detecting their native forms. We demonstrate such a method, which combines mass spectrometry with mild reductions, requires no prior experimentation or knowledge of proteins' physicochemical characteristics, function or activity, and is amenable to automation. These are necessary criteria for structural genomics and proteomics applications.

Multi-step evolution of protein conformation on electrospray into the gas phase.

In the gas phase, some properties of native versus denatured protein conformations correspond to those in solution, such as affinity for protons and physical cross section. However, the capacity for hydrogen/deutrerium exchange is the opposite, with ubiquitin 7+ and 13+ ions exchanging >-60 D and approximately 15 D atoms, respectively. A variety of experimental methods now delineate a series of conformational perturbations that can occur in the 10(-12) s to 10(+2) s following electrospray, including side-chain collapse, hydrophobic and electrostatic non-covalent bond unfolding and refolding into a variety of non-native structures.

Top-down MS, a powerful complement to the high capabilities of proteolysis proteomics.

For the characterization of protein sequences and post-translational modifications by MS, the 'top-down' proteomics approach utilizes molecular and fragment ion mass data obtained by ionizing and dissociating a protein in the mass spectrometer. This requires more complex instrumentation and methodology than the far more widely used 'bottom-up' approach, which instead uses such data of peptides from the protein's digestion, but the top-down data are far more specific. The ESI MS spectrum of a 14 protein mixture provides full separation of its molecular ions for MS/MS dissociation of the individual components.

Biosynthesis of the thioquinolobactin siderophore: an interesting variation on sulfur transfer.

The thioquinolobactin siderophore from Pseudomonas fluorescens ATCC 17400 utilizes a variation of the sulfur transfer chemistry found in thiamine and molydobterin biosynthesis. A JAMM motif protein cleaves the C-terminal amino acid residues following a diglycine moiety on a small sulfur carrier protein, and the modified C terminus is activated and sulfurylated, forming a thiocarboxylate.