Measurement of Formic Acid, Acetic Acid and Hydroxyacetaldehyde, Hydrogen Peroxide, and Methyl Peroxide in Air by Chemical Ionization Mass Spectrometry: Airborne Method

A chemical ionization mass spectrometry (CIMS) method utilizing a reagent gas mixture of O2, CO2, and CH3I in N2 is described and optimized for quantitative gas-phase measurements of hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HCOOH), and the sum of acetic acid (CH3COOH) and hydroxyacetaldehyde (HOCH2CHO; also known as glycolaldehyde). The instrumentation and methodology were designed for airborne in situ field measurements. The CIMS quantification of formic acid, acetic acid, and hydroxyacetaldehyde used I− cluster formation to produce and detect the ion clusters I−(HCOOH), I−(CH3COOH), and I−(HOCH2CHO), respectively. The CIMS also produced and detected I− clusters with hydrogen peroxide and methyl peroxide, I−(H2O2) and I−(CH3OOH), though the sensitivity was lower than with the O2− (CO2) and O2− ion clusters, respectively. For that reason, while the I− peroxide clusters are presented, the focus is on the organic acids. Acetic acid and hydroxyacetaldehyde were found to yield equivalent CIMS responses. They are exact isobaric compounds and indistinguishable in the CIMS used. Consequently, their combined signal is referred to as the acetic acid equivalent sum. Within the resolution of the quadrupole used in the CIMS (1m∕z), ethanol and 1- and 2-propanol were potential isobaric interferences to the measurement of formic acid and the acetic acid equivalent sum, respectively. The CIMS response to ethanol was 3.3% that of formic acid and the response to either 1- or 2-propanol was 1% of the acetic acid response; therefore, the alcohols were not considered to be significant interferences to formic acid or the acetic acid equivalent sum. The multi-reagent ion system was successfully deployed during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) in 2014. The combination of FRAPPÉ and laboratory calibrations allowed for the post-mission quantification of formic acid and the acetic acid equivalent sum observed during the Deep Convective Clouds and Chemistry Experiment in 2012

An Ion-Neutral Model to Investigate Chemical Ionization Mass Spectrometry Analysis of Atmospheric Molecules – Application to a Mixed Reagent Ion System for Hydroperoxides and Organic Acids

An ion-neutral chemical kinetic model is described and used to simulate the negative ion chemistry occurring within a mixed-reagent ion chemical ionization mass spectrometer (CIMS). The model objective was the establishment of a theoretical basis to understand ambient pressure (variable sample flow and reagent ion carrier gas flow rates), water vapor, ozone and oxides of nitrogen effects on ion cluster sensitivities for hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HFo) and acetic acid (HAc). The model development started with established atmospheric ion chemistry mechanisms, thermodynamic data and reaction rate coefficients. The chemical mechanism was augmented with additional reactions and their reaction rate coefficients specific to the analytes. Some existing reaction rate coefficients were modified to enable the model to match laboratory and field campaign determinations of ion cluster sensitivities as functions of CIMS sample flow rate and ambient humidity. Relative trends in predicted and observed sensitivities are compared as instrument specific factors preclude a direct calculation of instrument sensitivity as a function of sample pressure and humidity. Predicted sensitivity trends and experimental sensitivity trends suggested the model captured the reagent ion and cluster chemistry and reproduced trends in ion cluster sensitivity with sample flow and humidity observed with a CIMS instrument developed for atmospheric peroxide measurements (PCIMSs). The model was further used to investigate the potential for isobaric compounds as interferences in the measurement of the above species. For ambient O3 mixing ratios more than 50 times those of H2O2, O3−(H2O) was predicted to be a significant isobaric interference to the measurement of H2O2 using O2−(H2O2) at m∕z 66. O3 and NO give rise to species and cluster ions, CO3−(H2O) and NO3−(H2O), respectively, which interfere in the measurement of CH3OOH using O2−(CH3OOH) at m∕z 80. The CO3−(H2O) interference assumed one of its O atoms was 18O and present in the cluster in proportion to its natural abundance. The model results indicated monitoring water vapor mixing ratio, m∕z 78 for CO3−(H2O) and m∕z 98 for isotopic CO3−(H2O)2 can be used to determine when CO3−(H2O) interference is significant. Similarly, monitoring water vapor mixing ratio, m∕z 62 for NO3− and m∕z 98 for NO3−(H2O)2 can be used to determine when NO3−(H2O) interference is significant

Advances in multiple sclerosis research in 2009

The following review summarizes the progress in multiple sclerosis research published in the Journal of Neurology in 2009

Tolerability and safety of novel half milliliter formulation of glatiramer acetate for subcutaneous injection: an open-label, multicenter, randomized comparative study

Daily glatiramer acetate (GA) 20 mg/1.0 mL is a first-line treatment for relapsing-remitting multiple sclerosis (RRMS). To reduce the occurrence of injection pain and local injection site reactions (LISRs), a reduced volume formulation of GA was developed. This study compared pain and LISRs after injecting the marketed and the novel formulations. RRMS patients currently injecting GA participated in this multicenter, randomized, crossover comparative study. All patients administered once-daily subcutaneous injections of GA 20 mg/1.0 mL (marketed formulation) or GA 20 mg/0.5 mL (reduced volume formulation) for 14 days. Patients were crossed-over to the alternate treatment for an additional 14 days. Using a Visual Analog Scale (VAS), patients recorded in daily diaries the severity of injection pain immediately and 5 min post-injection, and the presence and severity of LISRs (swelling, redness, itching, lump) within 5 min and 24 h post-injection. VAS pain scores were ranked significantly lower immediately and 5 min after GA 20 mg/0.5 mL injections (p < 0.0001). Although LISRs were rare for both preparations, the severity of reactions ranked significantly lower and fewer symptoms occurred within 5 min and 24 h of using the reduced volume formulation (p < 0.0001). GA injected subcutaneously in a reduced volume formulation is a more tolerable option

Patient-rated suitability of a novel electronic device for self-injection of subcutaneous interferon beta-1a in relapsing multiple sclerosis: an international, single-arm, multicentre, Phase IIIb study

<p>Abstract</p> <p>Background</p> <p>Multiple sclerosis (MS) currently requires long-term treatment with disease-modifying drugs, administered parenterally up to once daily. The need for regular self-injection can be a barrier to treatment for many patients. Autoinjectors can help patients overcome problems or concerns with self-injection and could, therefore, improve treatment adherence. This study was performed to assess the suitability of a new electronic device for the subcutaneous (sc) administration of interferon (IFN) beta-1a, 44 mcg three times weekly, for relapsing MS.</p> <p>Methods</p> <p>In this Phase IIIb, multicentre, single-arm study, patients with relapsing MS who had been consistently self-injecting sc IFN beta-1a using an autoinjector for at least 6 weeks were taught to use the new device and self-administered treatment for 12 weeks thereafter. Patient-rated suitability of the device was assessed at the end of Week 12 using the Patient User Trial Questionnaire. Patient satisfaction with, and evaluation of, the injection process was assessed using the MS Treatment Concern Questionnaire. Trainers evaluated the device using the Trainer User Trial Questionnaire.</p> <p>Results</p> <p>At Week 12, 71.6% (73/102) of patients considered the device 'very suitable' or 'suitable' for self-injection; 92.2% (94/102) reported some degree of suitability and only 7.8% (8/102) found the device 'not at all suitable'. At Weeks 4, 8 and 12, most patients reported that injection preparation and clean-up, performing injections and ease of device use in the previous 4 weeks compared favourably with, or was equivalent to, their previous experience of self-injection. Injection-related pain, injection reactions and 'flu-like' symptoms remained stable over the 12 weeks. Each device feature was rated 'very useful' or 'useful' by at least 80% of patients. All trainers and 95.2% (99/104) of patients found device functions 'very easy' or 'easy' to use. Overall convenience was considered the most important benefit of the device.</p> <p>Conclusions</p> <p>Most patients considered the new electronic injection device suitable for the sc injection of IFN beta-1a. They found the device easy to use with useful features, and reported benefits such as overall convenience. The device may, therefore, increase treatment adherence in patients with MS, particularly those with injection-related issues.</p> <p>Trial registration</p> <p>NCT00735007</p

Patient adherence to and tolerability of self-administered interferon β-1a using an electronic autoinjection device: a multicentre, open-label, phase IV study

<p>Abstract</p> <p>Background</p> <p>Achieving good adherence to self-injected treatments for multiple sclerosis can be difficult. Injection devices may help to overcome some of the injection-related barriers to adherence that can be experienced by patients. We sought to assess short-term adherence to, and tolerability of, interferon (IFN) β-1a administered via electronic autoinjection device in patients with relapsing-remitting multiple sclerosis (RRMS).</p> <p>Methods</p> <p>BRIDGE (RebiSmart to self-inject Rebif serum-free formulation in a multidose cartridge) was a 12-week, multicentre, open-label, single-arm, observational, Phase IV study in which patients self-administered IFN β-1a (titrated to 44 μg), subcutaneously (sc), three times weekly, via electronic autoinjection device. Patients were assessed at baseline and 4-weekly intervals to Week 12 or early termination (ET) for: physical examinations; diary card completion (baseline, Weeks 4, 8 only); neurological examinations (baseline, Week 12/ET only); MS Treatment Concern Questionnaire (MSTCQ; Weeks 4, 8, 12 only); Convenience Questionnaire (Week 12 only); Hospital Anxiety and Depression Scale (HADS); and Paced Auditory Serial Addition Task (PASAT; baseline only). Adherence was defined as administration of ≥ 80% of scheduled injections, recorded by the autoinjection device.</p> <p>Results</p> <p>Overall, 88.2% (105/119; intent-to-treat population) of patients were adherent; 67.2% (80/119) administered all scheduled injections. Medical reasons accounted for 35.6% (31/87) of missed injections, forgetfulness for 20.6% (18/87). Adherence did not correlate with baseline Expanded Disability Status Scale (<it>P </it>= 0.821) or PASAT (<it>P </it>= 0.952) scores, or pre-study therapy (<it>P </it>= 0.303). No significant changes (baseline-Week 12) in mean HADS depression (<it>P </it>= 0.482) or anxiety (<it>P </it>= 0.156) scores were observed. 'Overall convenience' was the most important reported benefit of the autoinjection device. Device features associated with handling and ease of use were highly rated. Mean MSTCQ scores for 'flu-like' symptoms (<it>P </it>= 0.022) and global side effects (<it>P </it>= 0.002) significantly improved from Week 4-12. Mean MSTCQ scores for pain at injection site and injection pain increased from Week 4-12 (<it>P </it>< 0.001). Adverse events were mild/moderate. No new safety signals were identified.</p> <p>Conclusion</p> <p>Convenience and ease of use of the autoinjection device may improve adherence and, therefore, outcomes, in patients with RRMS receiving sc IFN β-1a.</p> <p>Trial registration</p> <p>EU Clinical Trials Register (EU-CTR; <url>http://www.clinicaltrialsregister.eu</url>): 2009-013333-24</p

Regulation of Hepatitis C Virion Production via Phosphorylation of the NS5A Protein

Hepatitis C virus (HCV) is a significant pathogen, infecting some 170 million people worldwide. Persistent virus infection often leads to cirrhosis and liver cancer. In the infected cell many RNA directed processes must occur to maintain and spread infection. Viral genomic RNA is constantly replicating, serving as template for translation, and being packaged into new virus particles; processes that cannot occur simultaneously. Little is known about the regulation of these events. The viral NS5A phosphoprotein has been proposed as a regulator of events in the HCV life cycle for years, but the details have remained enigmatic. NS5A is a three-domain protein and the requirement of domains I and II for RNA replication is well documented. NS5A domain III is not required for RNA replication, and the function of this region in the HCV lifecycle is unknown. We have identified a small deletion in domain III that disrupts the production of infectious virus particles without altering the efficiency of HCV RNA replication. This deletion disrupts virus production at an early stage of assembly, as no intracellular virus is generated and no viral RNA and nucleocapsid protein are released from cells. Genetic mapping has indicated a single serine residue within the deletion is responsible for the observed phenotype. This serine residue lies within a casein kinase II consensus motif, and mutations that mimic phosphorylation suggest that phosphorylation at this position regulates the production of infectious virus. We have shown by genetic silencing and chemical inhibition experiments that NS5A requires casein kinase II phosphorylation at this position for virion production. A mutation that mimics phosphorylation at this position is insensitive to these manipulations of casein kinase II activity. These data provide the first evidence for a function of the domain III of NS5A and implicate NS5A as an important regulator of the RNA replication and virion assembly of HCV. The ability to uncouple virus production from RNA replication, as described herein, may be useful in understanding HCV assembly and may be therapeutically important