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1.
Neurología (Barc., Ed. impr.) ; 37(9): 748-756, noviembre 2022. tab
Article in Spanish | IBECS | ID: ibc-212366

ABSTRACT

Introducción: En España el ictus es la sexta causa de discapacidad. Sus secuelas producen alteraciones motoras, sensoriales y cognitivas, que pueden minimizarse con una actuación terapéutica temprana. Por ello se necesitan instrumentos de evaluación rápida que detecten déficits en estas áreas. El Oxford Cognitive Screen Test (OCS) es un test breve diseñado para la valoración de funciones cognitivas en pacientes con ictus. Nuestro objetivo fue generar una versión española (OCS-E) realizando una adaptación lingüística y cultural.Material y métodosDiseño de validación lingüística con doble traducción y 10 reuniones de consenso del equipo investigador multidisciplinar. Tres estudios piloto administrando el test respectivamente a 5 usuarios potenciales, 23 personas sanas y 23 diagnosticadas de ictus isquémico (61%) o hemorrágico, con edades entre 31-88 años.ResultadosEl OCS-E mantiene las 10 tareas originales, la codificación de respuestas y el sistema de puntuación. Se modificaron y ampliaron las instrucciones de administración, lo que asegura la fiabilidad del contenido y de su aplicación. En 5 tareas se han modificado imágenes, números y frases. La tarea praxia se amplió para evaluar ambos miembros superiores. Los estudios piloto confirmaron que las personas de la población diana comprendían de forma adecuada las tareas, con independencia de la existencia de problemas cognitivos.ConclusionesLa adaptación cultural ha generado una versión lingüística y conceptualmente equivalente, permitiendo su estudio psicométrico y posterior aplicación en población española. El OCS-E puede ser un instrumento de cribado útil para evaluación rápida de funciones cognitivas postictus. (AU)


Introduction: Stroke is the sixth leading cause of disability in Spain. Patients may present motor, sensory, or cognitive sequelae, which can be minimised with early treatment. To this end, there is a need for quick-to-administer assessment tools to evaluate deficits in these areas. The Oxford Cognitive Screen (OCS) is a brief test specifically designed to assess cognitive function in patients with stroke. Our aim in this study is to report the linguistic and cultural adaptation of a Spanish-language version of the test (OCS-S).Material and methodsThe linguistic validation was conducted with a process of double translation and 10 consensus meetings of the multidisciplinary research team. We also performed 3 pilot studies, with 5 potential users, 23 healthy individuals, and 23 patients with stroke (ischaemic in 61% of cases and haemorrhagic in 39%), respectively; participants were aged between 31 and 88 years.ResultsThe OCS-S includes the 10 subtests, the coding of responses, and the scoring system from the original version. We modified and extended the instructions for administration in order to ensure the reliability of the content and its application. Five tasks were modified (images, numbers, and sentences) and the praxis subtest was modified to evaluate both hands. The pilot studies confirmed comprehension in the target population, independently of any cognitive problems.ConclusionsThe OCS-S is conceptually and linguistically equivalent to the original test, enabling psychometric assessment and application of the test in the Spanish population. The OCS-S may be a useful screening tool for quickly assessing cognitive function after stroke. (AU)


Subject(s)
Humans , Stroke , Health Expenditures , Neuronal Plasticity
2.
Neurologia (Engl Ed) ; 37(9): 748-756, 2022.
Article in English | MEDLINE | ID: mdl-34649818

ABSTRACT

INTRODUCTION: Stroke is the sixth leading cause of disability in Spain. Patients may present motor, sensory, or cognitive sequelae, which can be minimised with early treatment. To this end, there is a need for quick-to-administer assessment tools to evaluate deficits in these areas. The Oxford Cognitive Screen (OCS) is a brief test specifically designed to assess cognitive function in patients with stroke. Our aim in this study is to report the linguistic and cultural adaptation of a Spanish-language version of the test (OCS-S). METHODS: The linguistic validation was conducted with a process of double translation and 10 consensus meetings of the multidisciplinary research team. We also performed 3 pilot studies, with 5 potential users, 23 healthy individuals, and 23 patients with stroke (ischaemic in 61% of cases and haemorrhagic in 39%), respectively; participants were aged between 31 and 88 years. RESULTS: The OCS-S includes the 10 subtests, the coding of responses, and the scoring system from the original version. We modified and extended the instructions for administration in order to ensure the reliability of the content and its application. Five tasks were modified (images, numbers, and sentences) and the praxis subtest was modified to evaluate both hands. The pilot studies confirmed comprehension in the target population, independently of any cognitive problems. CONCLUSION: The OCS-S is conceptually and linguistically equivalent to the original test, enabling psychometric assessment and application of the test in the Spanish population. The OCS-S may be a useful screening tool for quickly assessing cognitive function after stroke.


Subject(s)
Language , Stroke , Humans , Adult , Middle Aged , Aged , Aged, 80 and over , Reproducibility of Results , Cognition , Stroke/complications , Linguistics
3.
Neurologia (Engl Ed) ; 2020 Jan 21.
Article in English, Spanish | MEDLINE | ID: mdl-31980284

ABSTRACT

INTRODUCTION: Stroke is the sixth leading cause of disability in Spain. Patients may present motor, sensory, or cognitive sequelae, which can be minimised with early treatment. To this end, there is a need for quick-to-administer assessment tools to evaluate deficits in these areas. The Oxford Cognitive Screen (OCS) is a brief test specifically designed to assess cognitive function in patients with stroke. Our aim in this study is to report the linguistic and cultural adaptation of a Spanish-language version of the test (OCS-S). MATERIAL AND METHODS: The linguistic validation was conducted with a process of double translation and 10 consensus meetings of the multidisciplinary research team. We also performed 3 pilot studies, with 5 potential users, 23 healthy individuals, and 23 patients with stroke (ischaemic in 61% of cases and haemorrhagic in 39%), respectively; participants were aged between 31 and 88 years. RESULTS: The OCS-S includes the 10 subtests, the coding of responses, and the scoring system from the original version. We modified and extended the instructions for administration in order to ensure the reliability of the content and its application. Five tasks were modified (images, numbers, and sentences) and the praxis subtest was modified to evaluate both hands. The pilot studies confirmed comprehension in the target population, independently of any cognitive problems. CONCLUSIONS: The OCS-S is conceptually and linguistically equivalent to the original test, enabling psychometric assessment and application of the test in the Spanish population. The OCS-S may be a useful screening tool for quickly assessing cognitive function after stroke.

4.
Ann Dermatol Venereol ; 145(11): 659-664, 2018 Nov.
Article in French | MEDLINE | ID: mdl-30217682

ABSTRACT

BACKGROUND: Foreign body granuloma is an inflammatory tissue reaction to exogenous material. Classically it appears on the face after aesthetic procedures. Herein we report for the first time three cases of facial granulomatous reactions to microbeads after arterial cervico-facial embolization. PATIENTS AND METHODS: Three patients underwent embolization of the facial arteries using Embogold® microbeads in a setting of epistaxis or tumoral hemostasis. Within 10 to 45 days painful, inflammatory, subcutaneous nodules appeared on the homolateral side of the face. Histological samples showed an inflammatory response with giant cells as well as the presence of microbeads in the skin. A favorable outcome was achieved with colchicine in one patient and with surgery in another; the third patient was lost to follow-up. DISCUSSION: The embolizing microspheres produced a local inflammatory reaction, with destruction of the vascular wall and bead migration to facial tissue leading to a granulomatous reaction. The occurrence of three cases within a period of few weeks, with several different operators and batches of products, is surprising considering the long-standing use of the product. There was no common comorbidity in the patients and no suggestion of trauma. Retrospective analysis of the product batches was normal. Gold staining could play a role in severe inflammatory response to Embogold® particles. CONCLUSION: These three cases illustrate the value of discussing potential foreign body granulomatous reaction in cases of facial nodules following cervico-facial embolization. Colchicine may offer a valuable therapeutic alternative.


Subject(s)
Arteries , Embolization, Therapeutic/instrumentation , Granuloma, Foreign-Body/etiology , Microspheres , Adult , Aged , Embolization, Therapeutic/adverse effects , Epistaxis/therapy , Face/blood supply , Humans , Male , Postoperative Complications , Preoperative Care
5.
Clin Exp Allergy ; 48(8): 1035-1049, 2018 08.
Article in English | MEDLINE | ID: mdl-29752757

ABSTRACT

BACKGROUND: Both subcutaneous and sublingual allergen immunotherapy (SCIT and SLIT) have been shown to effectively suppress allergic manifestations upon allergen exposure, providing long-term relief from symptoms in allergic disorders including allergic asthma. Clinical studies directly comparing SCIT and SLIT report a different kinetics and magnitude of immunological changes induced during treatment. Comparative studies into the mechanisms underlying immune suppression in SCIT and SLIT are lacking. OBJECTIVE: We aimed to establish an experimental model for grass pollen (GP) SCIT and SLIT that would allow a head-to-head comparison of the two treatments. METHODS: BALB/c mice were sensitized with GP extract, followed by SCIT and SLIT treatments with various GP dosages. Subsequently, we challenged mice with GP and measured airway responsiveness (AHR), GP-specific immunoglobulins, ear swelling tests (EST), eosinophilic inflammation in bronchoalveolar lavage fluid (BALF), and T cell cytokine release after restimulation of lung cells (IL-5, IL-10, and IL-13). RESULTS: We find that SLIT treatment was able to suppress allergen-induced AHR, while allergic inflammation was not effectively suppressed even at the highest GP dose in this model. In contrast, SCIT treatment induced higher levels of GP-specific IgG1, while SLIT was superior in inducing a GP-specific IgG2a response, which was associated with increased Th1 activity in lung tissue after SLIT, but not SCIT treatment. Interestingly, SCIT was able to suppress Th2-type cytokine production in lung cell suspensions, while SLIT failed to do so. CONCLUSIONS AND CLINICAL RELEVANCE: In conclusion, GP-SCIT suppresses Th2 inflammation and induced neutralizing antibodies, while GP-SLIT suppresses the clinically relevant lung function parameters in an asthma mouse model, indicating that the two application routes depend on partially divergent mechanisms of tolerance induction. Interestingly, these data mirror observations in clinical studies, underscoring the translational value of these mouse models.


Subject(s)
Allergens/immunology , Antibodies, Neutralizing/immunology , Asthma/immunology , Pollen/immunology , Th2 Cells/immunology , Administration, Sublingual , Animals , Antibody Specificity/immunology , Asthma/diagnosis , Asthma/therapy , Biomarkers , Cytokines/metabolism , Desensitization, Immunologic , Disease Models, Animal , Eosinophils/immunology , Eosinophils/metabolism , Female , Immunoglobulin G/immunology , Injections, Subcutaneous , Mice , Respiratory Hypersensitivity/diagnosis , Respiratory Hypersensitivity/immunology , Respiratory Hypersensitivity/therapy , Sublingual Immunotherapy , Th2 Cells/metabolism
6.
J Chromatogr A ; 1362: 43-8, 2014 Oct 03.
Article in English | MEDLINE | ID: mdl-25194623

ABSTRACT

A rapid analytical approach for the direct measurement of furfurals such as 2-furfural and 5-methyl-2-furfural at parts-per-billion level in Manuka honey is described. The approach employs a piston-cylinder based liquid-liquid extraction device using chloroform extraction solvent. This device substantially reduces extraction time by a factor of 120 times compared to solid phase micro-extraction and reduces solvent consumption by a factor of 25 times compared to liquid-liquid extraction with mechanical agitation. A recently commercialised capillary column offering a high degree of inertness permits separation and detection of the analytes at ultra-trace level without derivatisation. A three-port planar microfluidic device with a mid-point pressure is also incorporated to back-flush heavier compounds in the matrix to improve column longevity and overall system cleanliness. With this approach, analysis is conducted in less than 7min. Repeatability of retention times for all compounds is less than 0.1% (n=20). The compounds cited can be analysed over a range from 1ng/g to 10µg/g in honey with a 5ng/g limit of quantification (LOQ) and correlation coefficients of at least 0.999. Relative precision is less than 2.8% RSD (n=20) at 50ng/g level with analyte extraction efficiency of greater than 99% (n=3) over a range from 5ng/g to 10µg/g in the matrix described. The analytical system requires only minimal maintenance and is suitable for remote site deployment. Under the analytical conditions established and with a practical LOQ of 5ng/g, 100 samples can be analysed before septum/liner/o-ring replacements are needed. As a preventive measure, the pre-column can be replaced once every six months to maintain chromatographic fidelity.


Subject(s)
Chromatography, Gas/methods , Furaldehyde/analogs & derivatives , Honey/analysis , Liquid-Liquid Extraction/methods , Furaldehyde/analysis , Solvents/chemistry
7.
Am J Physiol Lung Cell Mol Physiol ; 307(3): L240-51, 2014 Aug 01.
Article in English | MEDLINE | ID: mdl-24816488

ABSTRACT

Exposure to cigarette smoke (CS) is the main risk factor for developing chronic obstructive pulmonary disease and can induce airway epithelial cell damage, innate immune responses, and airway inflammation. We hypothesized that cell survival factors might decrease the sensitivity of airway epithelial cells to CS-induced damage, thereby protecting the airways against inflammation upon CS exposure. Here, we tested whether Pim survival kinases could protect from CS-induced inflammation. We determined expression of Pim kinases in lung tissue, airway inflammation, and levels of keratinocyte-derived cytokine (KC) and several damage-associated molecular patterns in bronchoalveolar lavage in mice exposed to CS or air. Human bronchial epithelial BEAS-2B cells were treated with CS extract (CSE) in the presence or absence of Pim1 inhibitor and assessed for loss of mitochondrial membrane potential, induction of cell death, and release of heat shock protein 70 (HSP70). We observed increased expression of Pim1, but not of Pim2 and Pim3, in lung tissue after exposure to CS. Pim1-deficient mice displayed a strongly enhanced neutrophilic airway inflammation upon CS exposure compared with wild-type controls. Inhibition of Pim1 activity in BEAS-2B cells increased the loss of mitochondrial membrane potential and reduced cell viability upon CSE treatment, whereas release of HSP70 was enhanced. Interestingly, we observed release of S100A8 but not of double-strand DNA or HSP70 in Pim1-deficient mice compared with wild-type controls upon CS exposure. In conclusion, we show that expression of Pim1 protects against CS-induced cell death in vitro and neutrophilic airway inflammation in vivo. Our data suggest that the underlying mechanism involves CS-induced release of S100A8 and KC.


Subject(s)
Epithelial Cells/metabolism , Inflammation/metabolism , Lung/metabolism , Proto-Oncogene Proteins c-pim-1/metabolism , Smoking/adverse effects , Smoking/metabolism , Animals , Bronchoalveolar Lavage Fluid , Cell Death/physiology , Cells, Cultured , Chemokines/metabolism , Epithelial Cells/pathology , Female , HSP70 Heat-Shock Proteins/metabolism , Inflammation/pathology , Lung/pathology , Membrane Potential, Mitochondrial/physiology , Mice , Mice, Inbred BALB C , Neutrophils/metabolism , Neutrophils/pathology , Pulmonary Disease, Chronic Obstructive/metabolism , Pulmonary Disease, Chronic Obstructive/pathology , Smoking/pathology
8.
Neurochirurgie ; 60(1-2): 42-7, 2014.
Article in English | MEDLINE | ID: mdl-24656646

ABSTRACT

Advances in transsphenoidal surgery and endoscopic techniques have opened new perspectives for cavernous sinus (CS) approaches. The aim of this study was to assess the advantages and disadvantages of limited endoscopic transsphenoidal approach, as performed in pituitary adenoma surgery, for CS tumor biopsy illustrated with three clinical cases. The first case was a 46-year-old woman with a prior medical history of parotid adenocarcinoma successfully treated 10 years previously. The cavernous sinus tumor was revealed by right third and sixth nerve palsy and increased over the past three years. A tumor biopsy using a limited endoscopic transsphenoidal approach revealed an adenocarcinoma metastasis. Complementary radiosurgery was performed. The second case was a 36-year-old woman who consulted for diplopia with right sixth nerve palsy and amenorrhea with hyperprolactinemia. Dopamine agonist treatment was used to restore the patient's menstrual cycle. Cerebral magnetic resonance imaging (MRI) revealed a right sided CS tumor. CS biopsy, via a limited endoscopic transsphenoidal approach, confirmed a meningothelial grade 1 meningioma. Complementary radiosurgery was performed. The third case was a 63-year-old woman with progressive installation of left third nerve palsy and visual acuity loss, revealing a left cavernous sinus tumor invading the optic canal. Surgical biopsy was performed using an enlarged endoscopic transsphenoidal approach to the decompress optic nerve. Biopsy results revealed a meningothelial grade 1 meningioma. Complementary radiotherapy was performed. In these three cases, no complications were observed. Mean hospitalization duration was 4 days. Reported anatomical studies and clinical series have shown the feasibility of reaching the cavernous sinus using an endoscopic endonasal approach. Trans-foramen ovale CS percutaneous biopsy is an interesting procedure but only provides cell analysis results, and not tissue analysis. However, radiotherapy and radiosurgery have proven effective for SC meningiomas. When histological diagnosis is required, limited endoscopic transsphenoidal approach appears as a safe, fast, and useful alternative to the classical endocranial approach. Also, a tailored enlargement of the approach could be performed if optic nerve decompression is required. The feasibility of CS endoscopic transsphenoidal biopsy has prompted us to consider CS biopsy when the diagnosis of CS meningioma is uncertain.


Subject(s)
Cavernous Sinus/pathology , Meningeal Neoplasms/pathology , Meningioma/pathology , Pituitary Neoplasms/pathology , Skull Base Neoplasms/pathology , Adult , Biopsy , Female , Humans , Meningeal Neoplasms/surgery , Meningioma/diagnosis , Meningioma/surgery , Middle Aged , Neuroendoscopy , Neurosurgical Procedures/methods , Pituitary Neoplasms/diagnosis , Pituitary Neoplasms/surgery , Skull Base Neoplasms/diagnosis , Skull Base Neoplasms/surgery
9.
Anal Chim Acta ; 805: 101-6, 2013 Dec 17.
Article in English | MEDLINE | ID: mdl-24296149

ABSTRACT

A practical gas chromatographic approach is introduced for the characterization of trace ethylene glycol in industrial solvents and lubricants. The analytical approach employs single step derivatization technique that effectively converts ethylene glycol to the cyclic boronate ester (2-phenyl-1,3,2-dioxaborolane), using phenyl boronic acid as a derivatizing reagent. The separation of the derivatized product was achieved by using multidimensional gas chromatography. Heavy lubricant matrices like engine crankcase oil were back-flushed to improve sample throughput and system cleanliness. Detection and quantitation of 2-phenyl-1,3,2-dioxaborolane was conducted with mass spectrometry in selected ion monitoring mode. Complete analysis is conducted in less than 10 min. Reproducibility of retention time was found to be less than 0.05% (n=20). Quantitative performance is highly satisfactory, viz. 0.49±0.02 mg kg(-1) (n=12) and 25.5±0.48 mg kg(-1) (n=12) for 0.5 mg kg(-1) and 25 mg kg(-1) spiked concentrations respectively. Over a range from 100 µg kg(-1) to 100 mg kg(-1), the response for 2-phenyl-1,3,2-dioxaborolane is linear with correlation coefficient of 0.998, a practical detection limit of 50 µg kg(-1), and average spiked recoveries for the analyte in the matrices tested range from 93 to 99%. Propylene glycol can also be analyzed using the same approach and water does not inhibit the formation of the derivatives, most probably owing to the use of 2,2-dimethoxypropane as a solvent for the derivatizing agent.

10.
Anal Chem ; 85(13): 6219-23, 2013 Jul 02.
Article in English | MEDLINE | ID: mdl-23742653

ABSTRACT

The use of monoethylene glycol as an extraction medium for removing phenol and alkyl phenols in organic matrixes such as hydrocarbons is introduced and combined with a practical analytical multidimensional gas chromatography approach. The analytical approach has been successfully developed for the characterization of phenol, cresols, xylenols, and alkyl phenols like 4-ethylphenol and 2,3,5-trimethylphenol. The technique employs a single-step extraction of the analytes with monoethylene glycol and sonication, followed by multidimensional gas chromatography with mass spectrometry in selected ion monitoring mode for the detection and quantitation. Extraction efficiency of phenol approached 100% while cresols, xylenols, and 4-ethylphenol were 97% or higher and 2,3,5-trimethylphenol was better than 91% under the analytical conditions used. With the technique described, a complete analysis can be conducted in less than 16 min. Reproducibility of area counts at two levels, namely, 5 ppm(w) and 50 ppm(w) over a period of 2 days were found to be less than 4% (n = 20). The analytes of interest was found to be linear over a range from 100 ppb(w) to 250 ppm(w) with correlation coefficient of at least 0.999 and detection limit of 50 ppb(w) . Spike recoveries from 500 ppb(w) to 250 ppm(w) for all analytes range from 96 to 102%.


Subject(s)
Ethylene Glycol/chemistry , Gas Chromatography-Mass Spectrometry/methods , Phenol/analysis , Phenols/analysis , Phenol/chemistry , Phenols/chemistry
11.
J Chromatogr A ; 1297: 231-5, 2013 Jul 05.
Article in English | MEDLINE | ID: mdl-23726084

ABSTRACT

The detection of sulfur compounds in different hydrocarbon matrices, from light hydrocarbon feedstocks to medium synthetic crude oil feeds provides meaningful information for optimization of refining processes as well as demonstration of compliance with petroleum product specifications. With the incorporation of planar microfluidic devices in a novel chromatographic configuration, sulfur compounds from hydrogen sulfide to alkyl dibenzothiophenes and heavier distributions of sulfur compounds over a wide range of matrices spanning across a boiling point range of more than 650°C can be characterized, using one single analytical configuration in less than 25min. In tandem with a sulfur chemiluminescence detector for sulfur analysis is a flame ionization detector. The flame ionization detector can be used to establish the boiling point range of the sulfur compounds in various hydrocarbon fractions for elemental specific simulated distillation analysis as well as profiling the hydrocarbon matrices for process optimization. Repeatability of less than 3% RSD (n=20) over a range of 0.5-1000 parts per million (v/v) was obtained with a limit of detection of 50 parts per billion and a linear range of 0.5-1000 parts per million with a correlation co-efficient of 0.998.


Subject(s)
Flame Ionization/methods , Hydrocarbons/chemistry , Luminescent Measurements/methods , Microfluidic Analytical Techniques/methods , Sulfur Compounds/analysis , Limit of Detection , Reproducibility of Results
12.
J Chromatogr A ; 1288: 105-10, 2013 May 03.
Article in English | MEDLINE | ID: mdl-23523064

ABSTRACT

Volatile organic compounds such as light hydrocarbons, dienes, and aromatic compounds are often encountered in the manufacturing and processing environments of chemical and petrochemical segments. These compounds need to be closely monitored for process optimization, plant maintenance and industrial hygiene purposes. A high throughput analytical approach has been successfully developed and implemented for the accurate measurement of fourteen commonly encountered analytes. The approach incorporates a recently introduced 5-port planar microfluidic device configured for use as a Deans switch for multidimensional gas chromatography. The use of multidimensional gas chromatography allows the elimination of potential chromatographic contaminants with a substantial enhancement of stationary phase selectivity via the use of columns with different separation mechanisms, and the back-flushing of heavier undesired hydrocarbons. A low thermal mass gas chromatographic module was employed in the second dimension of the two-dimensional gas chromatography system and was used to provide independent temperature control, and rapid heating and cooling to meet the high throughput requirements. By successfully combining these concepts, complete analysis of fourteen targeted components can be conducted in less than 120s. Repeatability of retention times for all compounds was found to be less than 0.05% (n=20). Repeatability of area counts at two levels, namely 10ppmv and 1000ppmv over a period of two days was found to be less than 3% (n=20). Apart from methane, which has a detection limit of 0.4ppmv, the rest of the compounds were found to have detection limits of less than 0.2ppmv. Compounds of interest were found to be linear over a range of 500ppbv-3000ppmv with correlation coefficients greater than 0.999.


Subject(s)
Chromatography, Gas/instrumentation , Chromatography, Gas/methods , Microfluidic Analytical Techniques/instrumentation , Volatile Organic Compounds/analysis , High-Throughput Screening Assays/instrumentation , High-Throughput Screening Assays/methods , Limit of Detection , Reproducibility of Results , Volatile Organic Compounds/chemistry
13.
Anal Chem ; 85(6): 3369-73, 2013 Mar 19.
Article in English | MEDLINE | ID: mdl-23427942

ABSTRACT

A portable, fast gas chromatographic method for the direct measurement of the parts per billion level of sulfur-free odorants in commercially available natural gas is introduced. The approach incorporates a resistively heated, temperature-programmable silicon micromachined gas chromatograph that employs a standard capillary column for the fast separation of methyl and ethyl acrylate from the natural gas matrix. The separation approach is coupled to a micromachined differential mobility detector to enhance analyte detectability, and the overall selectivity obtained against the matrix is described. A complete analysis can be conducted in less than 70 s. Furthermore, these two compounds can be measured accurately in the presence of other common volatile sulfur-based odorants such as alkyl mercaptans and alkyl sulfides. Repeatability of less than 3% RSD (n = 20) over a range from 0.5 to 5 ppm was obtained with a limit of detection for the target compounds at 50 ppb (v/v) and a linear range from 0.5 to 50 ppm with a correlation coefficient of at least 0.997.

14.
J Chromatogr A ; 1271(1): 185-91, 2013 Jan 04.
Article in English | MEDLINE | ID: mdl-23218191

ABSTRACT

An integrated gas chromatographic system has been successfully developed and implemented for the measurement of oxygen, nitrogen, carbon monoxide, carbon dioxide and light hydrocarbons in one single analysis. These analytes are frequently encountered in critical industrial petrochemical and chemical processes like catalytic cracking of naphtha or diesel fuel to lighter components used in gasoline. The system employs a practical, effective configuration consisting of two three-port planar microfluidic devices in series with each other, having built-in fluidic gates, and a mid-point pressure source. The use of planar microfluidic devices offers intangible advantages like in-oven switching with no mechanical moving parts, an inert sample flow path, and a leak-free operation even with multiple thermal cycles. In this way, necessary features such as selectivity enhancement, column isolation, column back-flushing, and improved system cleanliness were realized. Porous layer open tubular capillary columns were employed for the separation of hydrocarbons followed by flame ionization detection. After separation has occurred, carbon monoxide and carbon dioxide were converted to methane with the use of a nickel-based methanizer for detection with flame ionization. Flow modulated thermal conductivity detection was employed to measure oxygen and nitrogen. Separation of all the target analytes was achieved in one single analysis of less than 12 min. Reproducibility of retention times for all compounds were found to be less than 0.1% (n=20). Reproducibility of area counts at two levels, namely 100 ppm(v) and 1000 ppm(v) over a period of two days were found to be less than 5.5% (n=20). Oxygen and nitrogen were found to be linear over a range from 20 ppm(v) to 10,000 ppm(v) with correlation coefficients of at least 0.998 and detection limits of less than 10 ppm(v). Hydrocarbons of interest were found to be linear over a range from 200 ppb(v) to 1000 ppm(v) with correlation coefficients of greater than 0.999 and detection limits of less than 100 ppb(v).


Subject(s)
Chromatography, Gas/methods , Gases/analysis , Hydrocarbons/analysis , Chemical Industry , Chromatography, Gas/instrumentation , Equipment Design , Microfluidic Analytical Techniques , Petroleum
15.
J Chromatogr A ; 1261: 136-41, 2012 Oct 26.
Article in English | MEDLINE | ID: mdl-22809518

ABSTRACT

A portable, fast gas chromatographic method for the direct measurement of part-per-billion level of ethylene oxide in medical work place atmospheres is introduced. Ethylene oxide is a chemical of significance in life science for its critical role as a highly effective sterilizing agent for heat sensitive surgical instruments. However, ethylene oxide is highly flammable, a suspected human carcinogen, is mutagenic, and henceforth, requires close monitoring. The approach incorporates a temperature-programmable silicon micromachined gas chromatograph for the fast separation of ethylene oxide from airborne organic interferences. The separation approach is hyphenated to a micromachined differential mobility detector, improving targeted analyte detection, and enhancing the overall selectivity obtained. A complete analysis can be conducted in less than 60s. Further, ethylene oxide in the matrix mentioned can be measured directly with low possibility of false positives and without the need for any sample pre-treatment, such as pre-concentration or derivatization. A relative precision of less than 5% RSD (n=20) over a range from 5 parts per billion (v/v) to 500 parts per billion (v/v) was obtained.


Subject(s)
Air Pollutants, Occupational/analysis , Environmental Monitoring/methods , Ethylene Oxide/analysis , Gas Chromatography-Mass Spectrometry/methods , Environmental Monitoring/instrumentation , Gas Chromatography-Mass Spectrometry/instrumentation , Reproducibility of Results , Sensitivity and Specificity , Temperature
16.
Neurochirurgie ; 58(4): 241-5, 2012 Aug.
Article in French | MEDLINE | ID: mdl-22464602

ABSTRACT

INTRODUCTION: Cerebrospinal fluid (CSF) leak is a frequent complication after trans-sphenoidal pituitary surgery. We try to determine the incidence, risk factors, diagnostic procedures, and management of CSF leaks following trans-sphenoidal pituitary macroadenoma surgery. METHODS: A retrospective analysis of 337 patients data. RESULTS: Postoperative CSF leaks occurred in 11 patients (3,1%). Ten patients had to be reoperated. Three patients had meningitis. Intraoperative CSF leak is the only significant predictive factor of postoperative CSF leak. Revision surgery, wide opening of the sella turcica and insufficient reconstruction of the sellar floor also seem to play a role (for six cases of postoperative CSF leak, the closure material had been excluded). CONCLUSION: Prevention of the postoperative CSF leak needs screening of intra-operative CSF leak. The strength of the sellar floor is essential in order to avoid the ejection of the closure material, related to the intracranial pression.


Subject(s)
Cerebrospinal Fluid Rhinorrhea/etiology , Endoscopy/methods , Pituitary Gland/surgery , Postoperative Complications/etiology , Sphenoid Bone/surgery , Cerebrospinal Fluid Rhinorrhea/prevention & control , Humans , Intraoperative Period , Meningitis/complications , Pituitary Neoplasms/surgery , Postoperative Complications/prevention & control , Predictive Value of Tests , Recurrence , Retrospective Studies , Sella Turcica/surgery , Tomography, X-Ray Computed
17.
J Chromatogr A ; 1255: 216-20, 2012 Sep 14.
Article in English | MEDLINE | ID: mdl-22410155

ABSTRACT

Oxygenated compounds like methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetaldehyde, crotonaldehyde, ethylene oxide, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and 2-chloromethyl-1,3-dioxolane are commonly encountered in industrial manufacturing processes. Despite the availability of a variety of column stationary phases for chromatographic separation, it is difficult to separate these solutes from their respective matrices using single dimension gas chromatography. Implemented with a planar microfluidic device, conventional two-dimensional gas chromatography and the employment of chromatographic columns using dissimilar separation mechanisms like that of a selective wall-coated open tubular column and an ionic sorbent column have been successfully applied to resolve twelve industrially significant volatile oxygenated compounds in both gas and aqueous matrices. A Large Volume Gas Injection System (LVGIS) was also employed for sample introduction to enhance system automation and precision. By successfully integrating these concepts, in addition to having the capability to separate all twelve components in one single analysis, features associated with multi-dimensional gas chromatography like dual retention time capability, and the ability to quarantine undesired chromatographic contaminants or matrix components in the first dimension column to enhance overall system cleanliness were realized. With this technique, a complete separation for all the compounds mentioned can be carried out in less than 15 min. The compounds cited can be analyzed over a range of 250 ppm (v/v) to 100 ppm (v/v) with a relative standard deviation of less than 5% (n=20) with high degree of reliability.


Subject(s)
Chromatography, Gas/methods , Microfluidic Analytical Techniques/instrumentation , Volatile Organic Compounds/analysis , Chromatography, Gas/instrumentation , Oxidation-Reduction , Oxygen/chemistry , Reproducibility of Results
18.
J Chromatogr A ; 1229: 223-9, 2012 Mar 16.
Article in English | MEDLINE | ID: mdl-22325017

ABSTRACT

Steam condensate water treatment is a vital and integral part of the overall cooling water treatment process. Steam condensate often contains varying levels of carbon dioxide and oxygen which acts as an oxidizer. Carbon dioxide forms corrosive carbonic acid when dissolved in condensed steam. To neutralize the harmful effect of the carbonic acid, volatile amine compounds such as morpholine, cyclohexylamine, and diethylaminoethanol are often employed as part of a strategy to control corrosion in the water treatment process. Due to the high stability of these compounds in a water matrix, the indirect addition of such chemicals into the process via steam condensate often results in their presence throughout the process and even into the final product. It is therefore important to understand the impact of these chemicals and their fate within a chemical plant. The ability to analyze such compounds by gas chromatography has historically been difficult due to the lack of chromatographic system inertness at the trace level concentrations especially in an aqueous matrix. Here a highly sensitive, practical, and reliable gas chromatographic approach is described for the determination of morpholine, cyclohexylamine, and diethylaminoethanol in steam condensate at the part-per-billion (ppb) levels. The approach does not require any sample enrichment or derivatization. The technique employs a multi-mode inlet operating in pulsed splitless mode with programmed inlet temperature for sample introduction, an inert base-deactivated capillary column for solute separation and flame ionization detection. Chromatographic performance was further enhanced by the incorporation of 2-propanol as a co-solvent. Detection limits for morpholine, cyclohexylamine, diethylaminoethanol were established to be 100 ppb (v/v), with relative standard deviations (RSD) of less than 6% at the 95% confidence level (n=20) and a percent recovery of 96% or higher for the solutes of interest over a range of 0.1-100 ppm (v/v). A complete analysis can be conducted in less than 10 min.


Subject(s)
Chromatography, Gas/methods , Cyclohexylamines/analysis , Ethanolamines/analysis , Morpholines/analysis , Steam/analysis , 2-Propanol/chemistry , Flame Ionization , Limit of Detection , Reproducibility of Results
19.
Thorax ; 67(6): 488-95, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22167364

ABSTRACT

BACKGROUND: House dust mite (HDM) allergens have been reported to increase airway epithelial permeability, thereby facilitating access of allergens and allergic sensitisation. OBJECTIVES: The authors aimed to understand which biochemical properties of HDM are critical for epithelial immune and barrier responses as well as T helper 2-driven experimental asthma in vivo. METHODS: Three commercially available HDM extracts were analysed for endotoxin levels, protease and chitinase activities and effects on transepithelial resistance, junctional proteins and pro-inflammatory cytokine release in the bronchial epithelial cell line 16HBE and normal human bronchial cells. Furthermore, the effects on epithelial remodelling and airway inflammation were investigated in a mouse model. RESULTS: The different HDM extracts varied extensively in their biochemical properties and induced divergent responses in vitro and in vivo. Importantly, the Greer extract, with the lowest serine protease activity, induced the most pronounced effects on epithelial barrier function and CCL20 release in vitro. In vivo, this extract induced the most profound epithelial E-cadherin delocalisation and increase in CCL20, CCL17 and interleukin 5 levels, accompanied by the most pronounced induction of HDM-specific IgE, goblet cell hyperplasia, eosinophilic inflammation and airway hyper-reactivity. CONCLUSIONS: This study shows the ability of HDM extracts to alter epithelial immune and barrier responses is related to allergic sensitisation but independent of serine/cysteine protease activity.


Subject(s)
Antigens, Dermatophagoides/immunology , Asthma/immunology , Pyroglyphidae/immunology , Respiratory Mucosa/immunology , Animals , Asthma/physiopathology , Biomarkers/metabolism , Cadherins/immunology , Chemokine CCL17/immunology , Chemokine CCL20/immunology , Cytokines/immunology , Dermatophagoides pteronyssinus/immunology , Disease Models, Animal , Humans , Hypersensitivity/immunology , In Vitro Techniques , Interleukin-5/immunology , Male , Mice , Mice, Inbred BALB C , Respiratory Mucosa/physiopathology
20.
J Chromatogr A ; 1217(3): 348-52, 2010 Jan 15.
Article in English | MEDLINE | ID: mdl-20004902

ABSTRACT

A practical gas chromatographic procedure has been developed and implemented for the measurement of arsine and phosphine in hydrocarbons such as propylene at the part-per-billion level. The successful measurement of arsine and phosphine at the level mentioned was attained by incorporating a large volume injection technique to increase the mass of solutes delivered for sensitivity improvement, capillary flow technology to keep the matrix from entering the detector by either back-flushing through the inlet vent, or by heart-cutting if required, and dielectric barrier discharge detector operating in argon mode for sensitivity enhancement, as well as offering improved selectivity towards the solutes cited. Using the technique described a complete analysis can be conducted in less than 4 min. A relative standard precision of less than 1.7% was achieved with repeated injections at the concentration level of 25 and 125 ppb (v/v) each of arsine and phosphine in nitrogen with a practical detection limit at the 5 ppb (v/v) level. Correlation coefficients of greater than 0.9999 were obtained for arsine and phosphine over a range from 10 to 2500 ppb (v/v). The analytical methodology was proven to be reliable in continuous operation during the first 6 months of deployment.


Subject(s)
Arsenicals/analysis , Chromatography, Gas/methods , Flow Injection Analysis/methods , Hydrocarbons/chemistry , Phosphines/analysis , Alkenes/chemistry , Chromatography, Gas/instrumentation , Flow Injection Analysis/instrumentation , Sensitivity and Specificity
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