"Uncorking" of liposomes by matrix metalloproteinase-9

A triggered release methodology of liposomal contents via the enzyme MMP-9 is described.     

Search for anomalous fragments produced in collisions with heavy target nuclei and in delta Z = 1 peripheral interactions

We exposed a stack of CR39 track detectors containing Ag foils to a 1.7-GeV/nucleon 56Fe beam and investigated the anomalous mean-free-path effect. Neither the whole set of 7517 nor a subset of 2542 interacting fragments produced probably in the Ag target show an effect. By combining the data of this and an earlier experiment we can also exclude an effect for 3219 interacting fragments produced in delta Z = 1 collisions.     

Direct and simultaneous quantitation of 5‐aminolaevulinic acid and porphobilinogen in human serum or plasma by hydrophilic interaction liquid chromatography–atmospheric pressure chemical ionization/tandem mass spectrometry

Serum/plasma concentrations of 5‐aminolaevulinic acid (ALA) and porphobilinogen (PBG) are elevated in patients with acute hepatic porphyrias, especially during acute attacks. Current assays require lengthy sample pre‐treatment and derivatization steps. We report here a rapid, sensitive and specific hydrophilic interaction liquid chromatography–tandem mass spectrometry method for the direct and simultaneous quantitation of ALA and PBG in serum or plasma following simple protein precipitation with acetonitrile and centrifugation prior to injection. ALA and PBG were detected using selected reaction monitoring mode, following positive atmospheric pressure chemical ionization. Calibration was linear from 0.05 to 50 µmol/L for ALA and PBG. For both analytes, imprecision (relative standard deviation) was <13% and accuracy (percentage nominal concentrations) was between 92 and 107%. The method was successfully applied to the measurement of ALA and PBG in serum or plasma samples for the screening, biochemical diagnosis and treatment monitoring of patients with acute hepatic porphyrias. Copyright © 2012 John Wiley & Sons, Ltd.     

Ultra high-performance liquid chromatography of porphyrins in clinical materials: column and mobile phase selection and optimisation

Ultra high-performance liquid chromatographic (UHPLC) systems on columns packed with materials ranging from 1.9 to 2.7 μm average particle size were assessed for the fast and sensitive analysis of porphyrins in clinical materials. The fastest separation was achieved on an Agilent Poroshell C(18) column (2.7 μm particle size, 50 × 4.6 mm i.d.), followed by a Thermo Hypersil Gold C(18) column (1.9 μm particle size, 50 × 2.1 mm i.d.) and the Thermo Hypersil BDS C(18) column (2.4 μm particle size, 100 × 2.1 mm i.d.). All columns required a mobile phase containing 1 m ammonium acetate buffer, pH 5.16, with a mixture of acetonitrile and methanol as the organic modifiers for optimum resolution of the type I and III isomers, particularly for uroporphyrin I and III isomers. All UHPLC columns were suitable and superior to conventional HPLC columns packed with 5 μm average particle size materials for clinical sample analysis.     

Microscale analysis of proteins in inner ear tissues and fluids with emphasis on endolymphatic sac, otoconia, and organ of Corti

Here we describe preparatory techniques adapted for the study of proteins of inner ear tissues and fluids that have allowed us to apply state-of-the-art analytical techniques in spite of the minute size and anatomical complexities of this organ. Illustrative examples address unresolved issues of functional and clinical significance. First, we demonstrate how quick-freezing and freeze drying prevents artifacts that arise from sampling endolymphatic sac (ES) content in the liquid state. This set the stage for the generation of the first protein profile of the ES. Identification of crucial proteins will help elucidate mechanisms of endolymph volume regulation and pathogenesis of Meniere's disease. Second, we show how a unique situation allowed identification of otoconial proteins by mass spectrometric analysis without prior separation and we discuss possible roles for these minor otoconins in otoconial development and prevention of degenerative diseases that affect balance. Finally, we demonstrate techniques for the precise dissection of organ of Corti and its substructures, while preserving their near normal chemical state. We extended an earlier study in which we identified a novel calcium-binding protein by IEF, oncomodulin, localized in the outer hair cells and show here the applicability of prefractionation for the screening of calcium-binding proteins of organ of Corti. These studies demonstrate how advanced preparatory and analytical techniques can be applied to studies of the inner ear.     

The experimental and simulated LET spectrum and charge spectrum from CR-39 detectors exposed to irons near CRaTER at BNL

Human will be sooner or later return to the moon and will eventually travel to the planets near Earth. Space radiation hazards are an important concern for human space flight in deep space where galactic cosmic rays (GCR) and solar energetic particles are dominated and radiation is much stronger than that in LEO (Low Earth Orbit) because in deep space there is no magnetosphere to screen charged particle and no big planet nearby to shadow the spacecraft.Research indicates that the impact of particle radiation on humans depends strongly on the particles' linear energy transfer (LET) and the radiation risk is dominated by high LET radiation. Therefore, radiation research on high LET should be emphasized and conducted systematically so as to make radiation risk as low as reasonably achievable (ALARA) for astronauts.Radiation around the moon can be measured with silicon detectors and/or CR-39 plastic nuclear track detectors (PNTDs). At present stage the silicon detectors are one of the preferred active dosimeters which are sensitive to all LET and CR-39 detectors are the preferred passive dosimeters which are sensitive to high LET (≥5 keV/μm water). CR-39 PNTDs can be used as personal dosimeters for astronauts. Both the LET spectrum and the charge spectrum for charged particles in space can be measured with silicon detectors and CR-39 detectors.Calibrations for a detector system combined with the silicon detectors CRaTER (Cosmic Rays Telescope for the Effects of Radiation) from Boston University and Massachusetts Institute of Technology, and the CR-39 PNTDs from JSC (Johnson Space Center) – SRAG (Space Radiation Analysis Group) were conducted by exposing the detector system to the accelerator generated protons and heavy ions. US space mission for the radiation measurement around the moon using CRaTER was carried out in 2009.Results obtained from the calibration exposures indicate an excellent agreement between LET spectrum and charge spectrum measured with CR-39 detectors and simulated with PHITS (Particle and Heavy Ion Transport System).This paper introduces the LET spectrum method and charge spectrum method using CR-39 PNTDs and the Monte Carlo simulation method for CR-39 detectors, presents and compares the results measured with CR-39 PNTDs and simulated for CR-39 detectors exposed to heavy irons (600 MeV/n) in BNL (Brookhaven National Laboratory) in front and behind the CRaTER.