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1.
J Allergy Clin Immunol ; 143(4): 1395-1402, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30537475

RESUMEN

BACKGROUND: The safety of long-acting ß-agonists added to inhaled corticosteroids for the treatment of persistent asthma has been controversial. OBJECTIVE: We sought to determine whether administering formoterol in combination with mometasone furoate increases the risk of serious asthma outcomes (SAOs) compared with mometasone furoate alone. This clinical trial is registered as NCT01471340. METHODS: We conducted a 26-week, randomized, double-blind trial in adolescent and adult patients (≥12 years) with persistent asthma in 35 countries with the primary objective of evaluating whether mometasone furoate-formoterol increases the risk of SAOs (adjudicated hospitalization, intubation, or death) compared with mometasone furoate alone. The key efficacy end point was asthma exacerbation (composite of hospitalization of ≥24 hours, emergency department visits of <24 hours requiring systemic corticosteroids, or use of systemic corticosteroids for ≥3 consecutive days). RESULTS: Among 11,729 patients (mometasone furoate-formoterol, n = 5,868; mometasone furoate, n = 5,861), a total of 81 SAOs, all asthma-related hospitalizations, were observed in 71 patients: 45 events from 39 patients receiving mometasone furoate-formoterol and 36 events from 32 patients receiving mometasone furoate. The hazard ratio for the first SAO in the mometasone furoate-formoterol versus mometasone furoate group was 1.22 (95% CI, 0.76-1.94; P = .411). Asthma exacerbation occurred in 1,487 patients: 708 receiving mometasone furoate-formoterol and 779 receiving mometasone furoate. The hazard ratio for the first asthma exacerbation in the mometasone furoate-formoterol versus mometasone furoate group was 0.89 (95% CI, 0.80-0.98; P = .021). CONCLUSIONS: The addition of formoterol to mometasone furoate maintenance therapy did not increase the risk of serious asthma-related events and reduced the risk of asthma exacerbation.


Asunto(s)
Asma/tratamiento farmacológico , Broncodilatadores/uso terapéutico , Combinación Furoato de Mometasona y Fumarato de Formoterol/uso terapéutico , Adolescente , Adulto , Anciano , Niño , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Furoato de Mometasona/uso terapéutico , Brote de los Síntomas , Adulto Joven
2.
Eur Respir J ; 51(1)2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29301919

RESUMEN

In severe asthma, poor control could reflect issues of medication adherence or inhaler technique, or that the condition is refractory. This study aimed to determine if an intervention with (bio)feedback on the features of inhaler use would identify refractory asthma and enhance inhaler technique and adherence.Patients with severe uncontrolled asthma were subjected to a stratified-by-site random block design. The intensive education group received repeated training in inhaler use, adherence and disease management. The intervention group received the same intervention, enhanced by (bio)feedback-guided training. The primary outcome was rate of actual inhaler adherence. Secondary outcomes included a pre-defined assessment of clinical outcome. Outcome assessors were blinded to group allocation. Data were analysed on an intention-to-treat and per-protocol basis.The mean rate of adherence during the third month in the (bio)feedback group (n=111) was higher than that in the enhanced education group (intention-to-treat, n=107; 73% versus 63%; 95% CI 2.8%-17.6%; p=0.02). By the end of the study, asthma was either stable or improved in 54 patients (38%); uncontrolled, but poorly adherent in 52 (35%); and uncontrolled, but adherent in 40 (27%).Repeated feedback significantly improved inhaler adherence. After a programme of adherence and inhaler technique assessment, only 40 patients (27%) were refractory and adherent, and might therefore need add-on therapy.


Asunto(s)
Asma/tratamiento farmacológico , Asma/terapia , Biorretroalimentación Psicológica , Cumplimiento de la Medicación , Nebulizadores y Vaporizadores , Administración por Inhalación , Adulto , Anciano , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ápice del Flujo Espiratorio , Estudios Prospectivos
4.
Int Arch Allergy Immunol ; 156(1): 51-61, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21447959

RESUMEN

BACKGROUND: Atopic asthma is an allergic disease typically associated with T(H)2 cytokines. IL-17A is also associated with asthma, through the induction of chemokines. Mucosal CCL28 concentrations correlate with cellular recruitment to inflamed airways and support migration of IgA(+) B cells. Here, a link between IL-17A, CCL28 and IgE-secreting B cell chemotaxis is examined. METHODS: Primary human airway cells and the airway epithelial line A549 were used to characterize IL-17A receptor expression and the effect of IL-17A on CCL28 transcription and translation. B cells, differentiated to IgE+ cells ex vivo, were assessed for CCR10 surface expression and chemotaxis to CCL28 by flow cytometry, transwell migration and ELISpot. RESULTS: Human airway epithelium expressed both IL-17RA and IL-17RC, and was responsive to IL-17A stimulation. Cultured human IgE+ B cells expressed surface CCR10 and displayed CCR10-dependent chemotaxis towards recombinant CCL28. Enhanced levels of CCL28 were observed upon A549 cell incubation with IL-17A, and this up-regulation significantly increased the migration of IgE+ antibody-secreting B cells. The specificity of chemotaxis was confirmed by migration blockade in the presence of anti-CCL28 or anti-CCR10. CONCLUSIONS: This work identifies a novel chemokine for the migration of IgE+ B cells, in addition to characterizing induction of CCL28 by IL-17A. Taken together the results presented here propose a new role for IL-17A in the allergic airways, linking this cytokine with the recruitment of IgE+ antibody-secreting B cells, via the induction of CCL28. These observations justify further in vivo studies of larger cohorts.


Asunto(s)
Linfocitos B/fisiología , Quimiocinas CC/metabolismo , Quimiotaxis de Leucocito/fisiología , Inmunoglobulina E/metabolismo , Interleucina-17/inmunología , Adolescente , Asma/inmunología , Asma/metabolismo , Linfocitos B/inmunología , Linfocitos B/metabolismo , Línea Celular , Células Cultivadas , Quimiocinas CC/genética , Humanos , Hipersensibilidad/genética , Hipersensibilidad/inmunología , Hipersensibilidad/metabolismo , Interleucina-17/metabolismo , Receptores CCR10/biosíntesis , Receptores CCR10/genética
5.
JMIR Mhealth Uhealth ; 9(2): e25655, 2021 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-33591285

RESUMEN

BACKGROUND: Given the established links between an individual's behaviors and lifestyle factors and potentially adverse health outcomes, univariate or simple multivariate health metrics and scores have been developed to quantify general health at a given point in time and estimate risk of negative future outcomes. However, these health metrics may be challenging for widespread use and are unlikely to be successful at capturing the broader determinants of health in the general population. Hence, there is a need for a multidimensional yet widely employable and accessible way to obtain a comprehensive health metric. OBJECTIVE: The objective of the study was to develop and validate a novel, easily interpretable, points-based health score ("C-Score") derived from metrics measurable using smartphone components and iterations thereof that utilize statistical modeling and machine learning (ML) approaches. METHODS: A literature review was conducted to identify relevant predictor variables for inclusion in the first iteration of a points-based model. This was followed by a prospective cohort study in a UK Biobank population for the purposes of validating the C-Score and developing and comparatively validating variations of the score using statistical and ML models to assess the balance between expediency and ease of interpretability and model complexity. Primary and secondary outcome measures were discrimination of a points-based score for all-cause mortality within 10 years (Harrell c-statistic) and discrimination and calibration of Cox proportional hazards models and ML models that incorporate C-Score values (or raw data inputs) and other predictors to predict the risk of all-cause mortality within 10 years. RESULTS: The study cohort comprised 420,560 individuals. During a cohort follow-up of 4,526,452 person-years, there were 16,188 deaths from any cause (3.85%). The points-based model had good discrimination (c-statistic=0.66). There was a 31% relative reduction in risk of all-cause mortality per decile of increasing C-Score (hazard ratio of 0.69, 95% CI 0.663-0.675). A Cox model integrating age and C-Score had improved discrimination (8 percentage points; c-statistic=0.74) and good calibration. ML approaches did not offer improved discrimination over statistical modeling. CONCLUSIONS: The novel health metric ("C-Score") has good predictive capabilities for all-cause mortality within 10 years. Embedding the C-Score within a smartphone app may represent a useful tool for democratized, individualized health risk prediction. A simple Cox model using C-Score and age balances parsimony and accuracy of risk predictions and could be used to produce absolute risk estimations for app users.


Asunto(s)
Bancos de Muestras Biológicas , Aplicaciones Móviles , Estudios de Cohortes , Humanos , Estudios Prospectivos , Factores de Riesgo , Teléfono Inteligente , Reino Unido/epidemiología
6.
J Allergy Clin Immunol Pract ; 8(5): 1634-1644.e1, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31981733

RESUMEN

BACKGROUND: Because of historical safety concerns with the use of long-acting ß-agonists (LABA) in asthma, step-down from inhaled corticosteroid (ICS)/LABA combination therapy to ICS monotherapy is recommended once asthma control is achieved. OBJECTIVE: To evaluate the benefit/risk question about whether patients with asthma who achieve disease control on fixed-dose ICS/LABA combination therapy, such as mometasone furoate/formoterol fumarate (MF/F), should continue with this therapy or be stepped down to ICS monotherapy, such as MF. METHODS: Using data from 8447 clinically stable patients with persistent asthma in the Safety Pharma Investigation of Respiratory Outcomes trial who had been receiving a stable dose of ICS/LABA for ≥4 weeks, this post hoc analysis evaluated the risk of serious asthma outcomes (SAOs) (adjudicated hospitalization, intubation, or death) and asthma exacerbation (AEX) (composite of hospitalizations ≥24 hours, emergency visits <24 hours requiring systemic corticosteroid, or systemic corticosteroid for ≥3 consecutive days) in participants randomized to remain on ICS/LABA (MF/F) or step down to ICS (MF) for 26 weeks. RESULTS: There was no significant difference in SAO risk among patients maintained on ICS/LABA with MF/F compared with those who stepped down from ICS/LABA to MF (hazard ratio [HR], 1.03 [95% confidence interval (CI): 0.61, 1.75], P = .913). The risk of AEX was significantly lower in patients maintained on ICS/LABA with MF/F compared with those who stepped down from ICS/LABA to MF (HR, 0.87 [95% CI: 0.78, 0.98], P = .020). CONCLUSIONS: In this post hoc analysis of a large clinical trial dataset, maintenance on ICS/LABA with MF/F is not associated with an increased risk of SAOs and also significantly reduces the risk of AEX compared with step-down from ICS/LABA to MF.


Asunto(s)
Corticoesteroides , Asma , Administración por Inhalación , Corticoesteroides/uso terapéutico , Agonistas de Receptores Adrenérgicos beta 2/uso terapéutico , Asma/tratamiento farmacológico , Quimioterapia Combinada , Fumarato de Formoterol/uso terapéutico , Humanos , Furoato de Mometasona/uso terapéutico
9.
Drug Discov Today ; 11(5-6): 267-72, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16580604

RESUMEN

Understanding the quality of a screening collection is the first step to improving it and, as a result, the quality of the screening process. This article outlines how this issue was approached at GlaxoSmithKline and some of the hurdles that needed to be overcome to achieve success. The article focuses specifically on the necessary software and hardware infrastructure needed, and at some of the extra benefits of such a project in terms of data mining and data modelling.


Asunto(s)
Técnicas Químicas Combinatorias/métodos , Industria Farmacéutica/métodos , Almacenamiento y Recuperación de la Información/métodos , Cromatografía Líquida de Alta Presión , Técnicas Químicas Combinatorias/organización & administración , Computadores , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Control de Calidad , Programas Informáticos
10.
BMJ Open ; 6(1): e009350, 2016 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-26729384

RESUMEN

INTRODUCTION: In clinical practice, it is difficult to distinguish between patients with refractory asthma from those with poorly controlled asthma, where symptoms persist due to poor adherence, inadequate inhaler technique or comorbid diseases. We designed an audio recording device which, when attached to an inhaler, objectively identifies the time and technique of inhaler use, thereby assessing both aspects of adherence. This study will test the hypothesis that feedback on these two aspects of adherence when passed on to patients improves adherence and helps clinicians distinguish refractory from difficult-to-control asthma. METHODS: This is a single, blind, prospective, randomised, clinical trial performed at 5 research centres. Patients with partially controlled or uncontrolled severe asthma who have also had at least one severe asthma exacerbation in the prior year are eligible to participate. The effect of two types of nurse-delivered education interventions to promote adherence and inhaler technique will be assessed. The active group will receive feedback on their inhaler technique and adherence from the new device over a 3-month period. The control group will also receive training in inhaler technique and strategies to promote adherence, but no feedback from the device. The primary outcome is the difference in actual adherence, a measure that incorporates time and technique of inhaler use between groups at the end of the third month. Secondary outcomes include the number of patients who remain refractory despite good adherence, and differences in the components of adherence after the intervention. Data will be analysed on an intention-to-treat and a per-protocol basis. The sample size is 220 subjects (110 in each group), and loss to follow-up is estimated at 10% which will allow results to show a 10% difference (0.8 power) in adherence between group means with a type I error probability of 0.05. TRIAL REGISTRATION NUMBER: NCT01529697; Pre-results.


Asunto(s)
Antiasmáticos/administración & dosificación , Retroalimentación , Cumplimiento de la Medicación , Nebulizadores y Vaporizadores , Administración por Inhalación , Antiasmáticos/uso terapéutico , Asma , Equipos y Suministros Eléctricos , Electrónica , Humanos , Estudios Prospectivos , Proyectos de Investigación , Índice de Severidad de la Enfermedad , Método Simple Ciego
11.
Int Arch Allergy Immunol ; 99(2-4): 200-203, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-34167197

RESUMEN

There is increasing evidence implicating the central role of cells of monocyte/macrophage lineage in the pathogenesis of bronchial asthma. This evidence comes from studies on peripheral blood monocytes. BAL fluid and cells and, more recently, airway immunohistochemistry. Elucidation of the mechanisms of macrophage interactions may eventually lead to novel approaches in anti-asthma therapy.

12.
Pediatr Pulmonol ; 49(3): 205-13, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24420817

RESUMEN

Successfully diagnosing concomitant asthma in people with cystic fibrosis (CF) is a challenging proposition, and the utility of conventional diagnostic criteria of asthma in CF populations remains uncertain. Nonetheless, the accurate identification of individuals with CF and asthma allows appropriate tailoring of therapy, and should reduce the unnecessary use of asthma medication in broader CF cohorts. In this review, we discuss the diagnostic challenge posed by asthma in CF, both in terms of clinical evaluation, and of interpretation of pulmonary function testing and non-invasive markers of airway inflammation. We also examine how the role of cross-sectional thoracic imaging in CF and asthma can assist in the diagnosis of asthma in these patients. Finally, we critically appraise the evidence base behind the use of asthma medications in CF populations, with a particular focus on the use of inhaled corticosteroids and bronchodilators. As shall be discussed, the gaps in the current literature make further high-quality research in this field imperative.


Asunto(s)
Asma/diagnóstico , Fibrosis Quística/diagnóstico , Pulmón/fisiopatología , Antiasmáticos/uso terapéutico , Asma/complicaciones , Asma/tratamiento farmacológico , Fibrosis Quística/complicaciones , Fibrosis Quística/tratamiento farmacológico , Humanos , Pulmón/diagnóstico por imagen , Pruebas de Función Respiratoria , Tomografía Computarizada por Rayos X
13.
Chest ; 142(3): 673-679, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22383660

RESUMEN

BACKGROUND: The implementation of workplace smoking bans has contributed to a significant reduction in the incidence of acute coronary syndrome admissions, but their influence on adult acute pulmonary disease admissions is unclear. We sought to assess the impact of a national smoking ban on nationwide admissions of individuals of working age with acute pulmonary illness. METHODS: Data relating to emergency hospital admissions of subjects aged 20 to 70 years preceding and succeeding the implementation of the Irish smoking ban were obtained from a central registry. Population, weather, pollution, and influenza data were obtained from the relevant authorities. Poisson regression analysis was used to assess adjusted risk of emergency hospital admission following implementation of the smoking ban. RESULTS: Overall admissions with pulmonary illness decreased from 439 per 100,000 population per annum to 396 per 100,000 population per annum following the ban (unadjusted relative risk [RR], 0.91; 95% CI, 0.83-0.99; P = .048). This persisted following adjustment for confounding factors (adjusted RR, 0.85; 95% CI, 0.72-0.99; P = .04) and was most marked among younger age groups and in admissions due to asthma (adjusted RR, 0.60; 95% CI, 0.39-0.91; P = .016). Admissions with acute coronary syndromes (adjusted RR, 0.82; 95% CI, 0.70-0.97; P = .02), but not stroke (adjusted RR, 0.93; 95% CI, 0.73-1.20; P = .60), were also reduced. CONCLUSIONS: The implementation of a nationwide workplace smoking ban is associated with a decline in admissions with acute pulmonary disease among specific age groups and an overall reduction in asthma admissions. This may result from reduced exposure of vulnerable individuals to environmental tobacco smoke, emphasizing the potential benefit of legislation reducing second-hand smoke exposure.


Asunto(s)
Enfermedad Aguda/epidemiología , Enfermedades Pulmonares/epidemiología , Exposición Profesional/efectos adversos , Admisión del Paciente/estadística & datos numéricos , Cese del Hábito de Fumar , Contaminación por Humo de Tabaco/efectos adversos , Síndrome Coronario Agudo/epidemiología , Adulto , Anciano , Asma/epidemiología , Servicio de Urgencia en Hospital/estadística & datos numéricos , Servicio de Urgencia en Hospital/tendencias , Humanos , Incidencia , Irlanda/epidemiología , Persona de Mediana Edad , Admisión del Paciente/tendencias , Análisis de Regresión , Estudios Retrospectivos , Lugar de Trabajo
14.
Rapid Commun Mass Spectrom ; 22(22): 3673-82, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18956437

RESUMEN

Supercritical fluid chromatography (SFC) is fast becoming a technique of choice for the analysis of a wide range of compounds and has been found to be complementary to high-performance liquid chromatography (HPLC). The combination of SFC and mass spectrometry (MS) affords a very useful tool in the separation and analysis of compounds. In this study the ionisation of samples in the absence of an applied electrospray voltage has been observed when using SFC/MS, with some compounds showing increased sensitivity when all ionisation source high voltage (HV) is removed. In an attempt to understand the mechanism of ionisation, a series of test compounds were analysed using standard electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI) source configurations and also different API source designs. In both cases, data were acquired with the applied high voltage on (normal conditions) or with the high voltage off, i.e. no voltage spray (novo-spray). The standards were analysed with a range of pressure and modifier percentage conditions. To understand the nature of the ionisation process observed, this was compared with three established liquid-to-gas ionisation mechanisms. These were thermospray (TSP), charge residue model (CRM) of ESI and sonic spray ionisation (SSI). Experiments were undertaken in an attempt to explain this ionisation phenomenon and quantify any observed change in sensitivity. The most important point to note is that enhanced ionisation was observed under novo-spray conditions in a SFC/MS configuration, which in certain cases provides a lowering in the overall limit of detection (LOD).


Asunto(s)
Cromatografía con Fluido Supercrítico/métodos , Iones/química , Espectrometría de Masa por Ionización de Electrospray/métodos
15.
Cell Immunol ; 238(2): 87-96, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16581045

RESUMEN

CCL28 is a mucosal chemokine that attracts eosinophils and T cells via the receptors CCR3 and CCR10. Consequently, it is a candidate mediator of the pathology associated with asthma. This study examined constitutive and induced expression of CCL28 by A549 human airway epithelial-like cells. Real-time RT-PCR and ELISA of cultured cells and supernatants revealed constitutive levels of CCL28 expression to be low, whereas IL-1beta and TNF-alpha, induced significantly increased expression. Observations from induced sputum and human airway biopsies supported this. Signal transduction studies revealed that IL-1beta and TNF-alpha stimulation induced NFkappaB phosphorylation in A549 cells, but antagonist inhibition of NFkappaB p50-p65 phosphorylation correlated with marked reduction of IL-1beta or TNF-alpha induced CCL28 expression. Together these studies imply a role for CCL28 in the orchestration of airway inflammation, and suggest that CCL28 is one link between microbial insult and the exacerbation of pathologies such as asthma, through an NFkappaB-dependent mechanism.


Asunto(s)
Quimiocinas/metabolismo , Células Epiteliales/efectos de los fármacos , Interleucina-1/farmacología , Pulmón/citología , FN-kappa B/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Regulación hacia Arriba/efectos de los fármacos , Línea Celular Tumoral , Quimiocinas/genética , Quimiocinas CC , Células Epiteliales/metabolismo , Humanos , FN-kappa B/antagonistas & inhibidores , Fosforilación , ARN Mensajero/genética , Esputo/metabolismo
16.
Rapid Commun Mass Spectrom ; 16(5): 433-41, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-11857728

RESUMEN

A simple method for the derivatization of primary amines and carboxylic acids with tris(trimethoxyphenyl)phosphonium (TMPP) reagents to enhance their detection by electrospray mass spectrometry (ESI-MS) has been developed. The synthesis of novel TMPP reagents and their stable isotopically labelled analogues is described. Through the use of stable isotopically labelled TMPP "tags", incorporation of a doublet (1:1, (1)H/(2)H or (12)C/(13)C) into the target molecule can be achieved, enabling the use of isotopic target analysis to detect compounds of unknown molecular weight but with a characteristic isotope pattern and accurate mass difference.

17.
Rapid Commun Mass Spectrom ; 16(14): 1377-88, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12112618

RESUMEN

A system is presented that demonstrates the principle of on-line and on-chip post-column derivatisation reactions in micro-high-performance liquid chromatography (micro-HPLC) hyphenated to electrospray time-of-flight mass spectrometry (ESI-TOFMS). In this micro-HPLC-chip-MS set-up, the analytes are separated using gradient micro-HPLC and subsequently derivatised on-chip and detected. One of the major limitations of MS detection is its dependency on the degree of ionisation, which is widely variable and compound-specific. Optimising and controlling the degree of ionisation in a simple manner would allow MS detection to be truly generic. One way of achieving this is by pre-ionisation of analytes using simple derivatisation procedures that are both rapid and quantitative. Performing this in situ on the system described here overcomes issues of sample handling and efficiency losses when time-consuming "bench chemistry" is necessary prior to analysis. The power of the system is demonstrated by the separation of primary and secondary amines, which are subsequently derivatised with a positively charged phosphonium complex and detected in an enhanced manner. Typically, molecular cations (M(+)) are detected showing that the ionisation process is dominated by the phosphonium species, leading to more constant ionisation for a variety of compounds. In addition, stable isotopically labelled ((12)C/(13)C)-phosphonium reagent is used for the reactions, allowing for inherent signal/noise (S/N) improvement and automated data processing using cluster analysis. A similar reaction scheme is used for the derivatisation of ketones and aldehydes, also demonstrating dramatic increases in sensitivity, especially with increasing temperature. Minimal loss in chromatographic fidelity in terms of retention times is observed by the introduction of the micromixer chip into the system. Optimal flow rates in micro-HPLC and ESI-MS are compatible with flow rates for the chip as well as a multitude of in-line optical detectors including UV and fluorescence. In addition, the micromixer chip can be positioned pre-column if preferred. The system is robust, easily fully automated and applicable to a wide variety of reactions. The system has a major advantage in its simple robust connection to the "normal scale" outside world.

18.
Rapid Commun Mass Spectrom ; 17(6): 603-20, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12621624

RESUMEN

A simple method has been developed for the pre-column derivatisation of low molecular weight primary and secondary amines and carboxylic acids using quaternary nitrogen compounds to enhance their detection by liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS). The synthesis of seven novel quaternary nitrogen reagents is described. The derivatives are designed to be relatively small molecules to avoid some of the steric hindrance problems that may be associated with larger derivatisation reagents. The compounds have amine and carboxylic acid functional groups with which to derivatise carboxylic acids and amines, respectively. Two of the compounds contain a bromine atom in order to assess the advantages of a bromine isotope pattern in the mass spectra. This acts as a simple marker for derivatisation and enables data processing by cluster analysis. Activation of the carboxylic acid group was achieved by the use of either 1-chloro-4-methylpyridinium iodide (CMPI) or the more reactive 1-fluoro-4-methylpyridinium p-toluenesulphonate (FMP).1 Using both of these active reagents, the degree of nucleophilic substitution was investigated for the derivatisation of a variety of small molecules. Whilst giving some increase in the ESI-MS response for the derivatised compounds, the FMP itself acted as a derivatising reagent in a competing reaction. In the light of this finding, FMP was reacted with the test compounds separately and gave positive results as a derivatising reagent. Detection of the 'pre-charged' derivatives of amines and carboxylic acids by LC/ESI-MS was investigated with respect to their ESI response and chromatography.

19.
Rapid Commun Mass Spectrom ; 17(5): 484-97, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12590398

RESUMEN

The synthesis of S-pentafluorophenyl tris(2,4,6-trimethoxyphenyl)phosphonium acetate bromide (TMPP-AcPFP) and the novel compound (4-hydrazino-4-oxobutyl) [tris(2,4,6-trimethoxyphenyl)phosphonium bromide (TMPP-PrG) is described and the use of these compounds as derivatizing reagents for alcohols, aldehydes and ketones evaluated. Methods have been developed for the pre-column derivatization of alcohols using TMPP-AcPFP and for aldehydes and ketones using TMPP-PrG. The reactions were investigated by the use of a variety of individual test compounds containing the target functional groups. The TMPP acetyl ester and TMPP propyl hydrazone derivatives formed with their respective target analytes produced an enhanced response in electrospray ionization mass spectrometry (ESI-MS), and reproducible chromatography. The use of these two reagents to derivatize and facilitate detection of alcohols (including sugars and steroids), aldehydes and ketones (including steroids) by LC/ESI-MS was investigated.


Asunto(s)
Alcoholes/química , Aldehídos/química , Cromatografía Liquida/métodos , Cetonas/química , Compuestos Organofosforados/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Bromuros/química , Indicadores y Reactivos
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