Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Cephalalgia ; 41(9): 1027-1032, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33874755

RESUMEN

OBJECTIVE: We propose a new outcome measure to assess the efficacy of migraine treatments translating the approach of the Global Burden of Disease studies from a societal to an individual level: Instead of calculating "years lived with disability", we suggest estimating "time lost due to an attack". METHODS: Time lost due to an attack is calculated by multiplying the duration and the degree of impaired functioning during an attack. RESULTS: Time lost due to an attack, different from other outcome measures, does not just focus on the short-term analgesic effects of treatments, but rather on the improvement of all migraine symptoms and restoration of functioning, also considering therapy-related impairment. Importantly, time lost due to an attack measures the entire time patients are not functioning normally, from onset to complete resolution. CONCLUSIONS: Time lost due to an attack represents a new paradigm to assess migraine burden in single patients for a patient-centered evaluation of both acute and prophylactic treatments.


Asunto(s)
Costo de Enfermedad , Trastornos Migrañosos/tratamiento farmacológico , Medición de Resultados Informados por el Paciente , Evaluación de la Discapacidad , Carga Global de Enfermedades , Humanos , Dimensión del Dolor , Factores de Tiempo , Resultado del Tratamiento
2.
Neurocrit Care ; 33(1): 39-48, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32096121

RESUMEN

BACKGROUND: Biomarkers indicative of intracerebral hemorrhage (ICH) may help triage acute stroke patients in the pre-hospital phase. We hypothesized that serum concentration of glial fibrillary acidic protein (GFAP) in combination with ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1), measured by a rapid bio-assay, could be used to distinguish ICH from ischemic stroke. METHODS: This prospective two-center study recruited patients with a clinical diagnosis of acute stroke both in the pre-hospital phase and at hospital admission (within 4 and 6 h after symptom onset, respectively). Blood samples were analyzed for concentrations of GFAP and UCH-L1 using ELISA techniques. The reference standard was the diagnosis of ICH, ischemic stroke, or stroke mimicking condition achieved after clinical workup including brain imaging. RESULTS: A total of 251 patients were included (mean age [± SD] 72 ± 15 years; 5 ICH, 23 ischemic strokes and 14 stroke mimics in the pre-hospital part; and 59 ICH, 148 ischemic strokes and 2 stroke mimics in the in-hospital part). Mean delay (± SD) from symptom onset to blood withdrawal was 130 ± 79 min for the pre-hospital patients and 136 ± 86 min for the in-hospital patients. Both GFAP and UCH-L1 serum concentrations were higher in patients having ICH as compared to other diagnoses (GFAP: median 330 ng/L [interquartile range 64-7060, range 8-56,100] vs. 27.5 ng/L [14-57.25, 0-781], p < 0.001; UCH-L1: 401 ng/L [265-764, 133-1812] vs. 338 ng/L [213-549.5, 0-2950], p = 0.025). Area-under-the-curve values were 0.866 (95% CI 0.809-0.924, p < 0.001) for GFAP, and 0.590 (0.511-0.670, p = 0.033) for UCH-L1. Regarding overall diagnostic accuracy, UCH-L1 did not add significantly to the performance of GFAP. CONCLUSIONS: GFAP may differentiate ICH from ischemic stroke and stroke mimics. A point-of-care test to distinguish between ischemic and hemorrhagic strokes might facilitate triage to different treatment pathways or locations, or be used to select patients for trials of ultra-early interventions.


Asunto(s)
Proteína Ácida Fibrilar de la Glía/sangre , Accidente Cerebrovascular Hemorrágico/sangre , Accidente Cerebrovascular Isquémico/sangre , Ubiquitina Tiolesterasa/sangre , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Femenino , Accidente Cerebrovascular Hemorrágico/diagnóstico , Humanos , Accidente Cerebrovascular Isquémico/diagnóstico , Masculino , Persona de Mediana Edad , Pruebas en el Punto de Atención
3.
Environ Microbiol ; 17(10): 3937-48, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25943904

RESUMEN

The xoxF gene, encoding a pyrroloquinoline quinone-dependent methanol dehydrogenase, is found in all known proteobacterial methylotrophs. In several newly discovered methylotrophs, XoxF is the active methanol dehydrogenase, catalysing the oxidation of methanol to formaldehyde. Apart from that, its potential role in methylotrophy and carbon cycling is unknown. So far, the diversity of xoxF in the environment has received little attention. We designed PCR primer sets targeting clades of the xoxF gene, and used 454 pyrosequencing of PCR amplicons obtained from the DNA of four coastal marine environments for a unique assessment of the diversity of xoxF in these habitats. Phylogenetic analysis of the data obtained revealed a high diversity of xoxF genes from two of the investigated clades, and substantial differences in sequence composition between environments. Sequences were classified as being related to a wide range of both methylotrophs and non-methylotrophs from Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. The most prominent sequences detected were related to the family Rhodobacteraceae, the genus Methylotenera and the OM43 clade of Methylophilales, and are thus related to organisms that employ XoxF for methanol oxidation. Furthermore, our analyses revealed a high degree of so far undescribed sequences, suggesting a high number of unknown bacterial species in these habitats.


Asunto(s)
Oxidorreductasas de Alcohol/genética , Oxidorreductasas de Alcohol/metabolismo , Alphaproteobacteria/genética , Betaproteobacteria/genética , Gammaproteobacteria/genética , Alphaproteobacteria/metabolismo , Organismos Acuáticos/genética , Organismos Acuáticos/metabolismo , Betaproteobacteria/metabolismo , Ciclo del Carbono , Formaldehído/metabolismo , Gammaproteobacteria/metabolismo , Metanol/metabolismo , Cofactor PQQ/metabolismo , Filogenia , Reacción en Cadena de la Polimerasa
4.
Environ Microbiol ; 17(10): 4007-18, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26033676

RESUMEN

A variety of culture-independent techniques have been developed that can be used in conjunction with culture-dependent physiological and metabolic studies of key microbial organisms in order to better understand how the activity of natural populations influences and regulates all major biogeochemical cycles. In this study, we combined deoxyribonucleic acid-stable isotope probing (DNA-SIP) with metagenomics and metaproteomics to characterize an uncultivated marine methylotroph that actively incorporated carbon from (13) C-labeled methanol into biomass. By metagenomic sequencing of the heavy DNA, we retrieved virtually the whole genome of this bacterium and determined its metabolic potential. Through protein-stable isotope probing, the RuMP cycle was established as the main carbon assimilation pathway, and the classical methanol dehydrogenase-encoding gene mxaF, as well as three out of four identified xoxF homologues were found to be expressed. This proof-of-concept study is the first in which the culture-independent techniques of DNA-SIP and protein-SIP have been used to characterize the metabolism of a naturally occurring Methylophaga-like bacterium in the marine environment (i.e. Methylophaga thiooxydans L4) and thus provides a powerful approach to access the genome and proteome of uncultivated microbes involved in key processes in the environment.


Asunto(s)
Redes y Vías Metabólicas/genética , Metanol/metabolismo , Piscirickettsiaceae/metabolismo , Agua de Mar/microbiología , Oxidorreductasas de Alcohol/genética , Secuencia de Bases , Biomasa , Carbono/metabolismo , ADN Bacteriano/genética , Genoma Bacteriano/genética , Marcaje Isotópico , Metagenómica/métodos , Datos de Secuencia Molecular , Piscirickettsiaceae/genética , Proteoma/genética , Proteómica/métodos , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
5.
Int J Nurs Pract ; 21 Suppl 3: 15-27, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26681665

RESUMEN

Patients with chronic lymphocytic leukaemia (CLL) are typically diagnosed at an advanced age and may have multiple co-existing conditions, augmenting the challenges of treating their CLL. Aggressive cytotoxic therapies are often poorly tolerated in this patient population. Obinutuzumab is a glycoengineered type II anti-CD20 monoclonal antibody indicated in combination with chlorambucil for previously untreated CLL. The approval of this drug was based on the pivotal CLL11 trial, which demonstrated longer progression-free survival vs. rituximab/chlorambucil and chlorambucil alone in patients with significant co-existing medical conditions and/or poor renal function. However, a higher risk of infusion-related reactions (IRRs) was demonstrated with obinutuzumab-based therapy. We highlight important nursing care considerations to help prevent and successfully manage IRRs and other important adverse events, to improve the treatment experience of patients receiving obinutuzumab infusions and to enable them to complete their treatment and receive optimal benefit. Premedication, drug handling, dosing, administration, monitoring and documentation are discussed.


Asunto(s)
Anticuerpos Monoclonales Humanizados/efectos adversos , Antineoplásicos/efectos adversos , Leucemia Linfocítica Crónica de Células B/tratamiento farmacológico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Antineoplásicos/uso terapéutico , Australia , Humanos
6.
Br J Haematol ; 167(2): 243-51, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25041261

RESUMEN

The efficacy of a fixed-dose rituximab schedule was prospectively explored in primary/acute refractory, relapsed or chronic (platelet count >10 × 10(9) /l and ≤50 × 10(9) /l) idiopathic thrombocytopenic purpura (ITP). Patients received two doses of rituximab (1000 mg) on days 1 and 15 and were followed-up on weeks 1-8, 12, 26, 39 and 52. A total of 122 patients were included in the safety population; efficacy was analysed in 108 patients. Overall response rate (ORR) at week 8, defined as the proportion of patients achieving complete response (CR; platelet count >150 × 10(9) /l) or partial response (PR; platelet count >50 × 10(9) /l) was 44%. Therapeutic response, defined as achieving a response at week 8, with at least a minor response (MR; platelet count >30 × 10(9) /l), sustained up to weeks 26 and 52 and accompanied by a reduction in ITP medications, was achieved in 44% (week 26) and 35% (week 52) of patients, respectively. Treatment was well tolerated with no safety concerns. While this study failed to meet its primary endpoint of an ORR of 50%, the efficacy of two fixed doses of rituximab appear to provide similar efficacy to the standard 375 mg/m(2) four-dose schedule in relapsed/chronic ITP.


Asunto(s)
Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Factores Inmunológicos/uso terapéutico , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales de Origen Murino/administración & dosificación , Anticuerpos Monoclonales de Origen Murino/efectos adversos , Enfermedad Crónica , Esquema de Medicación , Femenino , Humanos , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/efectos adversos , Masculino , Persona de Mediana Edad , Recuento de Plaquetas , Estudios Prospectivos , Púrpura Trombocitopénica Idiopática/sangre , Recurrencia , Rituximab , Resultado del Tratamiento , Adulto Joven
7.
J Laryngol Otol ; : 1-8, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38644734

RESUMEN

OBJECTIVE: Evidence for necrotising otitis externa (NOE) diagnosis and management is limited, and outcome reporting is heterogeneous. International best practice guidelines were used to develop consensus diagnostic criteria and a core outcome set (COS). METHODS: The study was pre-registered on the Core Outcome Measures in Effectiveness Trials (COMET) database. Systematic literature review identified candidate items. Patient-centred items were identified via a qualitative study. Items and their definitions were refined by multidisciplinary stakeholders in a two-round Delphi exercise and subsequent consensus meeting. RESULTS: The final COS incorporates 36 items within 12 themes: Signs and symptoms; Pain; Advanced Disease Indicators; Complications; Survival; Antibiotic regimes and side effects; Patient comorbidities; Non-antibiotic treatments; Patient compliance; Duration and cessation of treatment; Relapse and readmission; Multidisciplinary team management.Consensus diagnostic criteria include 12 items within 6 themes: Signs and symptoms (oedema, otorrhoea, granulation); Pain (otalgia, nocturnal otalgia); Investigations (microbiology [does not have to be positive], histology [malignancy excluded], positive CT and MRI); Persistent symptoms despite local and/or systemic treatment for at least two weeks; At least one risk factor for impaired immune response; Indicators of advanced disease (not obligatory but mut be reported when present at diagnosis). Stakeholders were unanimous that there is no role for secondary, graded, or optional diagnostic items. The consensus meeting identified themes for future research. CONCLUSION: The adoption of consensus-defined diagnostic criteria and COS facilitates standardised research reporting and robust data synthesis. Inclusion of patient and professional perspectives ensures best practice stakeholder engagement.

8.
Microorganisms ; 8(3)2020 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-32120978

RESUMEN

The marine trace gas dimethylsulfide (DMS) is the single most important biogenic source of atmospheric sulfur, accounting for up to 80% of global biogenic sulfur emissions. Approximately 300 million tons of DMS are produced annually, but the majority is degraded by microbes in seawater. The DMS precursor dimethylsulfoniopropionate (DMSP) and oxidation product dimethylsulphoxide (DMSO) are also important organic sulfur reservoirs. However, the marine sinks of dissolved DMSO remain unknown. We used a novel combination of stable and radiotracers to determine seasonal changes in multiple dissolved organic sulfur transformation rates to ascertain whether microbial uptake of dissolved DMSO was a significant loss pathway. Surface concentrations of DMS ranged from 0.5 to 17.0 nM with biological consumption rates between 2.4 and 40.8 nM·d-1. DMS produced from the reduction of DMSO was not a significant process. Surface concentrations of total DMSO ranged from 2.3 to 102 nM with biological consumption of dissolved DMSO between 2.9 and 111 nM·d-1. Comparisons between 14C2-DMSO assimilation and dissimilation rates suggest that the majority of dissolved DMSO was respired (>94%). Radiotracer microbial consumption rates suggest that dissimilation of dissolved DMSO to CO2 can be a significant loss pathway in coastal waters, illustrating the significance of bacteria in controlling organic sulfur seawater concentrations.

9.
J Nurses Prof Dev ; 35(4): 215-221, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31145186

RESUMEN

A new advancement model implemented at a large healthcare organization provided master's-prepared clinical nurses the opportunity to gain leadership skills through working with a nurse residency program while being mentored by nursing professional development practitioners. The outcomes of resource allocation and growth were valuable for the organization, and master's-prepared clinical nurses are now contributing towards the nurse residency program's leadership roles.


Asunto(s)
Internado y Residencia/organización & administración , Liderazgo , Mentores , Enfermeras y Enfermeros/normas , Desarrollo de Personal/organización & administración , Movilidad Laboral , Educación de Postgrado en Enfermería , Humanos , Pennsylvania
10.
Front Microbiol ; 9: 766, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29755426

RESUMEN

The Roseobacter group comprises a significant group of marine bacteria which are involved in global carbon and sulfur cycles. Some members are methylotrophs, using one-carbon compounds as a carbon and energy source. It has recently been shown that methylotrophs generally require a rare earth element when using the methanol dehydrogenase enzyme XoxF for growth on methanol. Addition of lanthanum to methanol enrichments of coastal seawater facilitated the isolation of a novel methylotroph in the Roseobacter group: Marinibacterium anthonyi strain La 6. Mutation of xoxF5 revealed the essential nature of this gene during growth on methanol and ethanol. Physiological characterization demonstrated the metabolic versatility of this strain. Genome sequencing revealed that strain La 6 has the largest genome of all Roseobacter group members sequenced to date, at 7.18 Mbp. Multilocus sequence analysis (MLSA) showed that whilst it displays the highest core gene sequence similarity with subgroup 1 of the Roseobacter group, it shares very little of its pangenome, suggesting unique genetic adaptations. This research revealed that the addition of lanthanides to isolation procedures was key to cultivating novel XoxF-utilizing methylotrophs from the marine environment, whilst genome sequencing and MLSA provided insights into their potential genetic adaptations and relationship to the wider community.

11.
Front Microbiol ; 5: 243, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24904556

RESUMEN

Acetone is an important oxygenated volatile organic compound (OVOC) in the troposphere where it influences the oxidizing capacity of the atmosphere. However, the air-sea flux is not well quantified, in part due to a lack of knowledge regarding which processes control oceanic concentrations, and, specifically whether microbial oxidation to CO2 represents a significant loss process. We demonstrate that (14)C labeled acetone can be used to determine microbial oxidation to (14)CO2. Linear microbial rates of acetone oxidation to CO2 were observed for between 0.75-3.5 h at a seasonally eutrophic coastal station located in the western English Channel (L4). A kinetic experiment in summer at station L4 gave a V max of 4.1 pmol L(-1) h(-1), with a K m constant of 54 pM. We then used this technique to obtain microbial acetone loss rates ranging between 1.2 and 42 pmol L(-1) h(-1.)(monthly averages) over an annual cycle at L4, with maximum rates observed during winter months. The biological turnover time of acetone (in situ concentration divided by microbial oxidation rate) in surface waters varied from ~3 days in February 2011, when in situ concentrations were 3 ± 1 nM, to >240 days in June 2011, when concentrations were more than twofold higher at 7.5 ± 0.7 nM. These relatively low marine microbial acetone oxidation rates, when normalized to in situ concentrations, suggest that marine microbes preferentially utilize other OVOCs such as methanol and acetaldehyde.

12.
ISME J ; 7(3): 568-80, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23178665

RESUMEN

Methanol biogeochemistry and its importance as a carbon source in seawater is relatively unexplored. We report the first microbial methanol carbon assimilation rates (k) in productive coastal upwelling waters of up to 0.117±0.002 d(-1) (~10 nmol l(-1 )d(-1)). On average, coastal upwelling waters were 11 times greater than open ocean northern temperate (NT) waters, eight times greater than gyre waters and four times greater than equatorial upwelling (EU) waters; suggesting that all upwelling waters upon reaching the surface (≤20 m), contain a microbial population that uses a relatively high amount of carbon (0.3-10 nmol l(-1 )d(-1)), derived from methanol, to support their growth. In open ocean Atlantic regions, microbial uptake of methanol into biomass was significantly lower, ranging between 0.04-0.68 nmol l(-1 )d(-1). Microbes in the Mauritanian coastal upwelling used up to 57% of the total methanol for assimilation of the carbon into cells, compared with an average of 12% in the EU, and 1% in NT and gyre waters. Several methylotrophic bacterial species were identified from open ocean Atlantic waters using PCR amplification of mxaF encoding methanol dehydrogenase, the key enzyme in bacterial methanol oxidation. These included Methylophaga sp., Burkholderiales sp., Methylococcaceae sp., Ancylobacter aquaticus, Paracoccus denitrificans, Methylophilus methylotrophus, Methylobacterium oryzae, Hyphomicrobium sp. and Methylosulfonomonas methylovora. Statistically significant correlations for upwelling waters between methanol uptake into cells and both chlorophyll a concentrations and methanol oxidation rates suggest that remotely sensed chlorophyll a images, in these productive areas, could be used to derive total methanol biological loss rates, a useful tool for atmospheric and marine climatically active gas modellers, and air-sea exchange scientists.


Asunto(s)
Metanol/metabolismo , Agua de Mar/microbiología , Movimientos del Agua , Oxidorreductasas de Alcohol/genética , Océano Atlántico , Bacterias/genética , Bacterias/metabolismo , Fenómenos Fisiológicos Bacterianos
13.
J Clin Oncol ; 30(14): 1594-600, 2012 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-22393084

RESUMEN

PURPOSE: The combination of pertuzumab and trastuzumab resulted in a clinical benefit rate (CBR) of 50% in patients with human epidermal growth factor receptor 2 (HER2) -positive breast cancer whose disease progressed during prior trastuzumab-based therapy. To define whether this previously observed encouraging activity was a result of the combination of pertuzumab and trastuzumab or of pertuzumab alone, we recruited a third cohort of patients who received pertuzumab without trastuzumab. We then investigated the impact of reintroducing trastuzumab to patients whose disease progressed on pertuzumab monotherapy. PATIENTS AND METHODS: Twenty-nine patients with HER2-positive breast cancer whose disease progressed during prior trastuzumab-based therapy received pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) until progressive disease or unacceptable toxicity. Seventeen patients with disease progression continued to receive pertuzumab (at the same dose), with the addition of trastuzumab (4 mg/kg loading dose and then 2 mg/kg weekly or 8 mg/kg loading dose and then 6 mg/kg every 3 weeks). RESULTS: All 29 patients enrolled for pertuzumab monotherapy experienced disease progression. The objective response rate (ORR) and CBR were 3.4% and 10.3%, respectively, during pertuzumab monotherapy. With the addition of trastuzumab, the ORR and CBR were 17.6% and 41.2%, respectively. Progression-free survival was longer with combination therapy than pertuzumab monotherapy (17.4 v 7.1 weeks, respectively). Treatment was well tolerated with minimal cardiac dysfunction. CONCLUSION: Although pertuzumab has some activity in patients with HER2-positive breast cancer that progressed during therapy with trastuzumab, the combination of pertuzumab and trastuzumab seems to be more active than monotherapy.


Asunto(s)
Anticuerpos Monoclonales Humanizados/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Receptor ErbB-2/metabolismo , Adulto , Factores de Edad , Anciano , Anticuerpos Monoclonales Humanizados/efectos adversos , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Humanos , Dosis Máxima Tolerada , Persona de Mediana Edad , Invasividad Neoplásica/patología , Estadificación de Neoplasias , Selección de Paciente , Pronóstico , Estudios Prospectivos , Medición de Riesgo , Análisis de Supervivencia , Trastuzumab , Resultado del Tratamiento
14.
ISME J ; 5(4): 704-16, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21068775

RESUMEN

Methanol is the predominant oxygenated volatile organic compound in the troposphere, where it can significantly influence the oxidising capacity of the atmosphere. However, we do not understand which processes control oceanic concentrations, and hence, whether the oceans are a source or a sink to the atmosphere. We report the first methanol loss rates in seawater by demonstrating that (14)C-labelled methanol can be used to determine microbial uptake into particulate biomass, and oxidation to (14)CO(2). We have found that methanol is used predominantly as a microbial energy source, but also demonstrated its use as a carbon source. We report biological methanol oxidation rates between 2.1 and 8.4 nmol l(-1) day(-1) in surface seawater of the northeast Atlantic. Kinetic experiments predict a V(max) of up to 29 nmol l(-1) day(-1), with a high affinity K(m) constant of 9.3 nM in more productive coastal waters. We report surface concentrations of methanol in the western English channel of 97±8 nM (n=4) between May and June 2010, and for the wider temperate North Atlantic waters of 70±13 nM (n=6). The biological turnover time of methanol has been estimated between 7 and 33 days, although kinetic experiments suggest a 7-day turnover in more productive shelf waters. Methanol uptake rates into microbial particles significantly correlated with bacterial and phytoplankton parameters, suggesting that it could be used as a carbon source by some bacteria and possibly some mixotrophic eukaryotes. Our results provide the first methanol loss rates from seawater, which will improve the understanding of the global methanol budget.


Asunto(s)
Bacterias/metabolismo , Metanol/metabolismo , Agua de Mar/microbiología , Biomasa , Océanos y Mares , Fitoplancton/metabolismo , Microbiología del Agua
15.
Anal Chim Acta ; 706(1): 128-34, 2011 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-21995919

RESUMEN

The role of the ocean in the cycling of oxygenated volatile organic compounds (OVOCs) remains largely unanswered due to a paucity of datasets. We describe the method development of a membrane inlet-proton transfer reaction/mass spectrometer (MI-PTR/MS) as an efficient method of analysing methanol, acetaldehyde and acetone in seawater. Validation of the technique with water standards shows that the optimised responses are linear and reproducible. Limits of detection are 27 nM for methanol, 0.7 nM for acetaldehyde and 0.3 nM for acetone. Acetone and acetaldehyde concentrations generated by MI-PTR/MS are compared to a second, independent method based on purge and trap-gas chromatography/flame ionisation detection (P&T-GC/FID) and show excellent agreement. Chromatographic separation of isomeric species acetone and propanal permits correction to mass 59 signal generated by the PTR/MS and overcomes a known uncertainty in reporting acetone concentrations via mass spectrometry. A third bioassay technique using radiolabelled acetone further supported the result generated by this method. We present the development and optimisation of the MI-PTR/MS technique as a reliable and convenient tool for analysing seawater samples for these trace gases. We compare this method with other analytical techniques and discuss its potential use in improving the current understanding of the cycling of oceanic OVOCs.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA