Matrix-assisted ionization Fourier transform mass spectrometry for the analysis of lipids.

RATIONALE: Assessing the utility of vacuum matrix-assisted ionization (MAI) for the direct and rapid analysis of lipids in complex samples with emphasis on bacterial taxonomy. METHODS: Matrix-assisted ionization Fourier transform mass spectrometry (MAI-FTMS) was used to characterize polar and non-polar lipids in mixtures. RESULTS: For non-polar lipid triacylglycerols (TAGs), MAI-FTMS produced lipid-specific ions for eight different edible oils and allowed these oils to be identified based on their MAI-FTMS profiles. For polar lipids from bacteria, MAI-FTMS of crude lipid extracts allowed taxonomic identification of eight blind-coded samples based on taxonomy-specific phospholipid profiles. MAI produced results comparable and complementary to benchmark MALDI and ESI methods currently used for characterization of polar and non-polar lipids in the same mixtures. CONCLUSIONS: The newly developed MAI technique is a rapid, simple and complementary method for the characterization of polar and non-polar lipids in complex mixtures.

Liquid Sampling-Atmospheric Pressure Glow Discharge Ionization as a Technique for the Characterization of Salt-Containing Organic Samples.

Typical ionization techniques used for mass spectrometry (MS) analysis face challenges when trying to analyze organic species in a high-salt environment. Here, we present results using a recently developed ionization source, liquid sampling-atmospheric pressure glow discharge (LS-APGD), for marine-relevant salt-containing organic samples. Using two representative sample types, a triglyceride mixture and dissolved organic matter, this method is compared to traditional electrospray ionization (ESI) under saline and neat conditions. LS-APGD produced equal or higher (15%+) ion intensities than those of ESI for both salt-containing and neat samples, although important differences linked with adduct formation in high-salt conditions explain the molecular species observed. For all sample types, LS-APGD observed a higher diversity of molecules under optimized settings (0.25 mm electrode spacing at 20 mA) compared to traditional ESI. Furthermore, because the LS-APGD source ionizes molecular species in a ∼1 mm3 volume plasma using a low-power source, there is the potential for this method to be applied in field studies, eliminating desalting procedures, which can be time-consuming and nonideal for low-concentration species.

Improved Outcomes Associated with the use of Shock Protocols: Updates from the National Cardiogenic Shock Initiative.

BACKGROUND: The National Cardiogenic Shock Initiative is a single-arm, prospective, multicenter study to assess outcomes associated with early mechanical circulatory support (MCS) in patients presenting with acute myocardial infarction and cardiogenic shock (AMICS) treated with percutaneous coronary intervention (PCI). METHODS: Between July 2016 and February 2019, 35 sites participated and enrolled into the study. All centers agreed to treat patients with AMICS using a standard protocol emphasizing invasive hemodynamic monitoring and rapid initiation of MCS. Inclusion and exclusion criteria mimicked those of the "SHOCK" trial with an additional exclusion criteria of intra-aortic balloon pump counter-pulsation prior to MCS. RESULTS: A total of 171 consecutive patients were enrolled. Patients had an average age of 63 years, 77% were male, and 68% were admitted with AMICS. About 83% of patients were on vasopressors or inotropes, 20% had a witnessed out of hospital cardiac arrest, 29% had in-hospital cardiac arrest, and 10% were under active cardiopulmonary resuscitation during MCS implantation. In accordance with the protocol, 74% of patients had MCS implanted prior to PCI. Right heart catheterization was performed in 92%. About 78% of patients presented with ST-elevation myocardial infarction with average door to support times of 85 ± 63 min and door to balloon times of 87 ± 58 min. Survival to discharge was 72%. Creatinine ≥2, lactate >4, cardiac power output (CPO) <0.6 W, and age ≥ 70 years were predictors of mortality. Lactate and CPO measurements at 12-24 hr reliably predicted overall mortality postindex procedure. CONCLUSION: In contemporary practice, use of a shock protocol emphasizing best practices is associated with improved outcomes.

Living Supramolecular Polymerisation of Perylene Diimide Amphiphiles by Seeded Growth under Kinetic Control.

The controlled solution self-assembly of an amphiphilic perylene diimide (PDI), with a hydrophobic perylene core and hydrophilic imide substituents with polydisperse oligo(ethylene glycol) (OEG) tethers is presented. It was possible, by a seeded-growth mechanism, to form colloidally stable, one-dimensional fibres with controllable lengths (from 400 to 1700 nm) and low dispersities (1.19-1.29) via a living supramolecular polymerisation process. Under the solvent conditions used, it was found that molecularly dissolved material (unimer) was present in samples of the fibre-like supramolecular assemblies. The free unimer may be present in a conformationally derived kinetically trapped state and/or may represent a more soluble PDI fraction with longer hydrophilic tethers. Significantly, it was also possible to form segmented supramolecular block copolymers by the addition of PDI unimer to chemically distinct PDI seeds, yielding fibres with controlled lengths. These results represent a significant advance in the ability to form PDI-based supramolecular polymers with precisely controlled lengths and architectures.

1D Self-Assembly and Ice Recrystallization Inhibition Activity of Antifreeze Glycopeptide-Functionalized Perylene Bisimides.

Antifreeze glycoproteins (AFGPs) are polymeric natural products that have drawn considerable interest in diverse research fields owing to their potent ice recrystallization inhibition (IRI) activity. Self-assembled materials have emerged as a promising class of biomimetic ice growth inhibitor, yet the development of AFGP-based supramolecular materials that emulate the aggregative behavior of AFGPs have not yet been reported. This work reports the first example of the 1D self-assembly and IRI activity of AFGP-functionalized perylene bisimides (AFGP-PBIs). Glycopeptide-functionalized PBIs underwent 1D self-assembly in water and showed modest IRI activity, which could be tuned through substitution of the PBI core. This work presents essential proof-of-principle for the development of novel IRIs as potential supramolecular cryoprotectants and glycoprotein mimics.

Matrix-assisted ionization vacuum for high-resolution Fourier transform ion cyclotron resonance mass spectrometers.

Matrix-assisted ionization vacuum (MAIV) produces charge states similar to electrospray ionization (ESI) from the solid state without requiring high voltage or added heat. MAIV differs from matrix-assisted laser desorption/ionization (MALDI) in that no laser is needed and abundant multiply charged ions are produced from molecules having multiple basic sites such as proteins. Here we introduce simple modifications to the commercial vacuum MALDI and ESI sources of a 9.4 T Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer to perform MAIV from both intermediate and atmospheric pressure. The multiply charged ions are shown for the proteins bovine insulin, ubiquitin, and lysozyme using 3-nitrobenzonitrile as matrix. These are the first examples of MAIV operating at pressures as low as 10(-6) mbar in an FT-ICR mass spectrometer source, and the expected mass resolving power of 100000 to 400000 is achieved. Identical protein charge states are observed with and without laser ablation indicating minimal, if any, role of photochemical ionization for the compounds studied.

Hepatic abscess associated with Salmonella serotype B in a chronic alcoholic patient.

BACKGROUND: Hepatic abscess secondary to Salmonella is extremely rare in the United States and other Western countries. METHODS: A 43-year-old Caucasian man, with a history of chronic alcohol abuse, was admitted to the hospital for intermittent abdominal pain, fever and diarrhea. Clinical, radiological and laboratory results were analyzed. Medical literature in PubMed pertaining to similar cases was reviewed. RESULTS: Stool culture was positive for Salmonella serotype B and a CT scan of the abdomen with contrast was consistent with a solitary hepatic abscess. Appropriate intravenous antibiotics followed by oral maintenance therapy for six weeks resulted in a complete clinical recovery and radiographic resolution. CONCLUSIONS: The cause of Salmonella hepatic abscess in our patient was most likely associated with decreased mucosal resistance to the bacteria, seeding of infection via transient portal bacteremia and loss of host immunity. Our case highlights the fact that appropriate antibiotic alone is sufficient in the management of a solitary hepatic abscess less than 3-5 cm.

Early Utilization of Mechanical Circulatory Support in Acute Myocardial Infarction Complicated by Cardiogenic Shock: The National Cardiogenic Shock Initiative.

BACKGROUND: Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) is associated with significant morbidity and mortality. Mechanical circulatory support (MCS) devices increase systemic blood pressure and end organ perfusion while reducing cardiac filling pressures. METHODS AND RESULTS: The National Cardiogenic Shock Initiative (NCT03677180) is a single-arm, multicenter study. The purpose of this study was to assess the feasibility and effectiveness of utilizing early MCS with Impella in patients presenting with AMI-CS. The primary end point was in-hospital mortality. A total of 406 patients were enrolled at 80 sites between 2016 and 2020. Average age was 64±12 years, 24% were female, 17% had a witnessed out-of-hospital cardiac arrest, 27% had in-hospital cardiac arrest, and 9% were under active cardiopulmonary resuscitation during MCS implantation. Patients presented with a mean systolic blood pressure of 77.2±19.2 mm Hg, 85% of patients were on vasopressors or inotropes, mean lactate was 4.8±3.9 mmol/L and cardiac power output was 0.67±0.29 watts. At 24 hours, mean systolic blood pressure improved to 103.9±17.8 mm Hg, lactate to 2.7±2.8 mmol/L, and cardiac power output to 1.0±1.3 watts. Procedural survival, survival to discharge, survival to 30 days, and survival to 1 year were 99%, 71%, 68%, and 53%, respectively. CONCLUSIONS: Early use of MCS in AMI-CS is feasible across varying health care settings and resulted in improvements to early hemodynamics and perfusion. Survival rates to hospital discharge were high. Given the encouraging results from our analysis, randomized clinical trials are warranted to assess the role of utilizing early MCS, using a standardized, multidisciplinary approach.

New structural insights into mechanically interlocked polymers revealed by ion mobility mass spectrometry.

Mechanically interlocked polymers can possess significant additional physical properties, in comparison to those associated with their constituent parts. Their unique properties make them attractive for a range of potential applications, such as as biomaterials and molecular machines. Their efficient and reproducible synthesis is therefore of much interest. Both their synthesis and subsequent characterization are intriguing yet demanding. The properties of mechanically interlocked polymeric systems depend not only on the properties of their individual components but also on the topology of the subsequent product. Here traveling wave ion mobility mass spectrometry has been used to investigate the structural properties of a polyrotaxane system. Ion mobility studies reveal that this system remains linear in form with increase in size. Both ion mobility studies and tandem mass spectrometry studies indicate that the macrocycle preferentially remains associated with the ammonium moiety of the polymeric repeat unit and is impeded from moving freely along the axle. This is consistent with NMR observations of the average structure. Analysis of mechanically interlocked polymers by ion mobility mass spectrometry provides additional structural insights into these systems relating to dynamics, heterogeneity, and topology. This molecule-specific information is vital in order to understand the origin of a system's functional properties.

Impella Mechanical Circulatory Support for Takotsubo Syndrome With Shock: A Retrospective Multicenter Analysis.

OBJECTIVES: To analyze the characteristics and outcome of Impella mechanical circulatory support (MCS) for Takotsubo syndrome (TS) with cardiogenic shock. BACKGROUND: TS is an acute heart failure syndrome characterized by transient severe reduction of left ventricular (LV) systolic function, with cardiogenic shock occurring in around 10% of patients. Since inotropes should be avoided due to their role in TS pathogenesis and aggravation of LV outflow tract obstruction, the use of MCS as treatment is a viable treatment option, however, studies are lacking. METHODS: The catheter-based ventricular assist device (cVAD) registry and local MCS databases were screened for TS patients with cardiogenic shock (TS-CS) supported with an Impella percutaneous ventricular assist device (pVAD). Patient and treatment characteristics and in-hospital outcomes were retrospectively analyzed. RESULTS: At 10 US and European centers, 16 TS-CS patients supported with an Impella pVAD were identified between December 2013 and May 2018 (mean age, 61.8 ± 15.5 years; 87.5% women). LV ejection fraction (LVEF) at presentation was severely reduced (mean, 19.4 ± 8.3%). Prior to MCS, 13 patients (81.3%) were mechanically ventilated, 4 patients (25.0%) had been resuscitated, and mean serum lactate was 4.7 ± 3.5 mmol/L. Mean duration of Impella support was 1.9 ± 1.0 days (range, 1-4 days). Thirteen patients (81.3%) survived to discharge, and all survivors experienced cardiac recovery with significant improvement of LVEF at discharge compared to baseline (20.4 ± 8.8 vs. 52.9 ± 12.0, P < 0.001). CONCLUSIONS: This is the first series of TS-CS patients supported with an Impella pVAD. Mortality was low, and LV systolic function recovered in all survivors. Prospective studies of Impella support in this special condition are warranted.

Growth mechanisms involved in the synthesis of smooth and microtextured films by acetylene magnetron discharges.

The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges of acetylene (C(2)H(2)) in an unbalanced magnetron setup was investigated. At 5 × 10(-3) Torr, only smooth films are obtained, whereas at 5 × 10(-1) Torr using a pulsed discharge some microtextured films are formed if the duty cycle is low. The morphology of these microtextured films consists of nanoparticles, filamentary particles, and particular agglomerates ("microflowers"). This paper presents a study of acetylene gas phase polymerization by mass spectrometry, and a detailed analysis of bulk structure of films by combining three techniques which include IR spectroscopy, Raman spectroscopy, and laser desorption/ionization Fourier transform mass spectrometry (LDI-FTMS). Finally, based on the study of gas phase and film structure, we propose a model for the growth of both smooth and microtextured films.

Programmable Assembly of π-Conjugated Polymers.

π-Conjugated polymers have numerous applications due to their advantageous optoelectronic and mechanical properties. These properties depend intrinsically on polymer ordering, including crystallinity, orientation, morphology, domain size, and π-π interactions. Programming, or deliberately controlling the composition and ordering of π-conjugated polymers by well-defined inputs, is a key facet in the development of organic electronics. Here, π-conjugated programming is described at each stage of material development, stressing the links between each programming mode. Covalent programming is performed during polymer synthesis such that complex architectures can be constructed, which direct polymer assembly by governing polymer orientation, π-π interactions, and morphological length-scales. Solution programming is performed in a solvated state as polymers dissolve, aggregate, crystallize, or react in solution. Solid-state programming occurs in the solid state and is governed by polymer crystallization, domain segregation, or gelation. Recent progress in programming across these stages is examined, highlighting order-dependent features and assembly techniques that are unique to π-conjugated polymers. This should serve as a guide for delineating the many ways of directing π-conjugated polymer assembly to control ordering, structure, and function, enabling the further development of organic electronics.

Oxidation promoted self-assembly of π-conjugated polymers.

Self-assembly is an attractive strategy for organizing molecules into ordered structures that can span multiple length scales. Crystallization Driven Self-Assembly (CDSA) involves a block copolymer with a crystallizable core-forming block and an amorphous corona-forming block that aggregate into micelles with a crystalline core in solvents that are selective for the corona block. CDSA requires core- and corona-forming blocks with very different solubilities. This hinders its use for the self-assembly of purely π-conjugated block copolymers since blocks with desirable optoelectronic properties tend to have similar solubilities. Further, this approach is not readily reversible, precluding stimulus-responsive assembly and disassembly. Here, we demonstrate that selective oxidative doping of one block of a fully π-conjugated block copolymer promotes the self-assembly of redox-responsive micelles. Heteroatom substitution in polychalcogenophenes enables the modulation of the intrinsic polymer oxidation potential. We show that oxidized micelles with a narrow size distribution form spontaneously and disassemble in response to a chemical reductant. This method expands the scope of π-conjugated polymers that can undergo controlled self-assembly and introduces reversible, redox-responsive self-assembly of π-conjugated polymers.

Surface Patterning of Uniform 2D Platelet Block Comicelles via Coronal Chain Collapse.

The formation of colloids with anisotropically patterned surfaces is of growing interest for the creation of hierarchical structures and the templating of nanoparticles. We have recently shown that well-defined two-dimensional platelets with low areal dispersities can be formed by the seeded growth of a blend of homopolymers and block copolymers. Herein we form rectangular platelets containing two block copolymers with different coronal chemistries. On addition of a solvent that is only able to solvate the corona of one block, we were able to form colloidally stable micelles with patterned surfaces via coronal collapse. Scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy and atomic force microscopy were employed to provide information on the structure and size of the patches decorating the micelle surfaces.

Outcomes of Hemodynamic Support With Impella for Acute Myocardial Infarction Complicated by Cardiogenic Shock at a Rural Community Hospital Without On-Site Surgical Back-up.

AIMS: Impella 2.5 and Impella CP (Abiomed) are percutaneous left ventricular assist devices that can be easily deployed in the cardiac catheterization laboratory without need for surgery and provide effective hemodynamic support. The utility of Impella devices for management of acute myocardial infarction complicated by cardiogenic shock (AMI-CS) at a rural community hospital without on-site surgical back-up has not been reported. METHODS: We retrospectively reviewed all consecutive patients who underwent percutaneous coronary intervention (PCI) with Impella support between 2012 and 2017 for AMI-CS at our institution. Survival, in-hospital complications, and recovery of native heart function at follow-up were assessed. RESULTS: A total of 90 consecutive patients (age, 63.8 ± 11.56 years; 28.8% female) with AMI-CS were supported with Impella and underwent PCI. At admission, 82.2% had cardiogenic shock and 32.2% sustained out-of-hospital cardiac arrest (OHCA). Survival rates at discharge, 30 days, 180 days, and 365 days were 61.1%, 60.0%, 57.7%, and 57.3%, respectively. Survivors were younger (P=.02) and had lower rates of OHCA (P<.01). Survival rate at 180 days was 72.4% when door-to-Impella support time was ≤48 minutes, 53.9% when Impella was initiated between 49 to 86 minutes, and 39.3% when Impella support was initiated after 86 minutes (P=.04). Recovery of native heart function was observed in 88.7% of 62 patients weaned off Impella support. CONCLUSIONS: Early hemodynamic support with the Impella percutaneous left ventricular assist device in severely ill patients with AMI-CS at a rural community hospital without on-site surgical back-up yielded very favorable survival outcomes, with recovery of native heart function.

Crystallization-Driven Self-Assembly of Metallo-Polyelectrolyte Block Copolymers with a Polycaprolactone Core-Forming Segment.

We report crystallization-driven self-assembly (CDSA) of metallo-polyelectrolyte block copolymers that contain cationic polycobaltocenium in the corona-forming block and crystallizable polycaprolactone (PCL) as the core-forming block. Dictated by electrostatic interactions originating from the cationic metalloblock and crystallization of the PCL, these amphiphilic block copolymers self-assembled into two-dimensional platelet nanostructures in polar protic solvents. The 2D morphologies can be varied from elongated hexagons to diamonds, and their stability to fragmentation was found to be dependent on the ionic strength of the solution.

Wide mass range trapping using a 7-T internal source matrix-assisted laser desorption/ionization Fourier transform mass spectrometer.

A wide mass range trapping experiment using internal source matrix-assisted laser desorption-Fourier transform mass spectrometry (MALDI-FTMS) was evaluated. In this method, the front trap plate potential is ramped up and the rear trap plate potential is simultaneously decreased using a cubic cell to trap ions over a wide range of mass-to-charge ratios. To apply this to MS/MS experiments, a second ion ejection procedure would remove unwanted ions, with the selected remaining ions then fragmented by collision-induced dissociation. In measurements using a 7.2-T unshielded magnet presented here, an approximately equimolar mixture of a set of poly(ethylene glycol) (PEG) species for the ramped measurements had peak areas of 1.0:1.0:1.0:1.0, as did the previously described integral method which gave peak areas of 1.0:1.1:1.0:1.0, in good agreement with the known composition of the samples deposited on the MALDI probe tip. Comparative MALDI-TOF in reflectron mode results were of similar quality for the equimolar mixture, giving a ratio of 1.0:1.0:1.2:0.9. All methods failed to varying degrees when individual PEG compositions of the trial mixture were changed. However, the previously described integral method showed relatively better results for all but the PEG 8000 doubled mixture.

Conditional standard errors of measurement for composite scores on the Wechsler Preschool and Primary Scale of Intelligence-Third Edition.

A specific recommendation of the 1999 Standards for Educational and Psychological Testing by the American Educational Research Association, the American Psychological Association, and the National Council on Measurement in Education is that test publishers report estimates of the conditional standard error of measurement (SEM). Procedures for calculating the conditional (score-level) SEM based on raw scores are well documented; however, few procedures have been developed for estimating the conditional SEM of subtest or composite scale scores resulting from a nonlinear transformation. Item response theory provided the psychometric foundation to derive the conditional standard errors of measurement and confidence intervals for composite scores on the Wechsler Preschool and Primary Scale of Intelligence-Third Edition.

Hydrocarbon polymer analysis by external MALDI fourier transform and reflectron time of flight mass spectrometry.

The traditional solvent-based matrix-assisted laser desorption ionization (MALDI) preparation method has been used to analyze nonpolar polymers of various molecular weights. High resolution silver cationized oligomers with masses of up to 12 KDa were measured using 9.4 tesla Fourier transform mass spectrometry (FTMS) with an external ionization source. It was observed that when time-of-flight mass spectrometry was used, the spectra of polyethylene polymers showed abundant low mass fragment ions. However, these fragments were absent from the FTMS spectra.