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1.
Orbit ; 37(6): 450-453, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29420104

RESUMEN

Dysthyroid optic neuropathy (DON) is one of the complications that can affect Graves' orbitopathy (GO) patients. Its prevalence is estimated at less than 5%. It is usually treated with intravenous steroids, radiotherapy or orbital decompression. Tocilizumab has been proposed as a treatment option in cases of GO refractory to steroid treatment, with good clinical results. Our aim is to report the case of a patient with optic neuropathy secondary to GO treated with tocilizumab as primary treatment option.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Oftalmopatía de Graves/complicaciones , Enfermedades del Nervio Óptico/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Enfermedades del Nervio Óptico/diagnóstico , Enfermedades del Nervio Óptico/etiología , Tomografía de Coherencia Óptica , Agudeza Visual/fisiología , Campos Visuales/fisiología
2.
Eur Respir J ; 39(4): 862-8, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21885395

RESUMEN

Chronic obstructive pulmonary disease (COPD) is a moderate risk factor for venous thromboembolism (VTE), but neither the clinical presentation nor the outcome of VTE in COPD patients is well known. The clinical presentation of VTE, namely pulmonary embolism (PE) or deep venous thrombosis (DVT), and the outcome at 3 months (death, recurrent VTE or bleeding) were compared between 2,984 COPD patients and 25,936 non-COPD patients included in the RIETE (Registro Informatizado de la Enfermedad TromboEmbólica) registry. This ongoing international, multi-centre registry includes patients with proven symptomatic PE or DVT. PE was the more frequent VTE presentation in COPD patients (n = 1,761, 59%). PE presentation was more significantly associated with COPD patients than non-COPD patients (OR 1.64, 95% CI 1.49-1.80). During the 3-month follow-up, mortality (10.8% versus 7.6%), minor bleeding (4.5% versus 2.3%) or first VTE recurrences as PE (1.5% versus 1.1%) were significantly higher in COPD patients than in non-COPD patients. PE was the most common cause of death. COPD patients presented more frequently with PE than DVT. It may explain the worse prognosis of COPD patients, with a higher risk of death, bleeding or VTE recurrences as PE compared with non-COPD patients. Further therapeutic options are needed.


Asunto(s)
Enfermedad Pulmonar Obstructiva Crónica/mortalidad , Embolia Pulmonar/mortalidad , Tromboembolia Venosa/mortalidad , Trombosis de la Vena/mortalidad , Anciano , Anciano de 80 o más Años , Femenino , Fibrinolíticos/uso terapéutico , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Pronóstico , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/tratamiento farmacológico , Sistema de Registros/estadística & datos numéricos , Factores de Riesgo , Resultado del Tratamiento , Filtros de Vena Cava , Tromboembolia Venosa/diagnóstico , Tromboembolia Venosa/terapia , Trombosis de la Vena/diagnóstico , Trombosis de la Vena/tratamiento farmacológico
3.
Int J Cosmet Sci ; 32(1): 65-72, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19889043

RESUMEN

A simple method for the simultaneous determination of a cationic surfactant (cetrimonium chloride) and four non-ionic surfactants (1-tetradecanol, 1-hexadecanol, 1-octadecanol and 1-eicosanol) has been developed. Direct extraction of the analytes from the sample with methanol and a subsequent separation using reversed-phase high-performance liquid chromatography with refractive index detection are the steps followed in the procedure. The column used was a Luna C18 and the mobile phase consisted of a 0.1 M KClO(4) solution prepared on a 95:5 mixture of methanol and water. This solution was adjusted to pH 2.8 with phosphoric acid. Recoveries close to 100% were obtained in spiked commercial hair conditioner samples for the surfactants assayed using this method. Limits of detection were 10.4, 16.7 and 22.9 mg kg(-1) of cetrimonium chloride, 1-hexadecanol, 1-hexadecanol and 1-1-octadecanol respectively. The methodology was successfully applied to nine commercial hair conditioners of several types and different brands. All hair conditioners but one contained at least two of the surfactants included in this study.


Asunto(s)
Alcoholes/análisis , Compuestos de Cetrimonio/análisis , Cromatografía Líquida de Alta Presión/métodos , Preparaciones para el Cabello/química , Cetrimonio , Cromatografía Líquida de Alta Presión/instrumentación , Humanos , Límite de Detección
4.
Food Chem ; 111(2): 469-75, 2008 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-26047452

RESUMEN

A HPLC-inductively coupled plasma atomic emission spectrometer (ICP-AES) hyphenation technique was used to determine the concentration of some organic (i.e., carbohydrates, carboxylic acids) as well as inorganic (metals and anions) compounds in tomato samples. A high efficiency nebulizer (HEN) coupled to a low inner volume cyclonic spray chamber (Cinnabar) was used to interface both techniques. The HPLC-ICP-AES chromatograms for organic compounds were obtained by plotting the 193.03nm carbon emission intensity versus time. In the present work, it was also possible to obtain information about the concentration of several metals in foodstuffs. Finally, by registering the intensity at the sulphur and phosphorous emission wavelengths, the content of anions such as sulphate and phosphate was determined. In general terms, the results obtained with HPLC-ICP-AES did not differ significantly from those found with a refractive index detector. Due to the huge amount of information provided by this hyphenation, it was possible to apply it to the discrimination among different samples of native tomato cultivars.

5.
Pathophysiol Haemost Thromb ; 36(1): 18-22, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-18332610

RESUMEN

Behçet's disease (BD) is associated with an increased risk of venous and arterial thromboses that are associated with morbidity and mortality increase, although the mechanisms are not well established. In the present study, we used whole blood cytometry to determine the exposure of CD62 on the surface of platelets and the expression of phosphatidylserine (PS) on the surface of circulating red blood cells. Microparticle and microaggregate formation from platelets were also determined in a well-classified group of 72 patients (39 males, 33 females, aged 46.5 +/- 12.5 years) with BD, in comparison with a well-matched control group of 72 healthy volunteers. Results showed no differences in the above-mentioned parameters when BD patients and controls were compared. However, when we compared BD patients with/without thrombosis using these parameters, there were significant differences between both groups. BD patients with previous thrombosis had a higher percentage of circulating CD62-positive platelets and a higher number of circulating microaggregates than those without thrombosis, suggesting that platelet activation may be involved in the development of thrombotic events in these patients.


Asunto(s)
Síndrome de Behçet/sangre , Membrana Eritrocítica/química , Fosfatidilserinas/sangre , Activación Plaquetaria , Trombofilia/etiología , Adulto , Síndrome de Behçet/complicaciones , Biomarcadores , Femenino , Fibrinolíticos/uso terapéutico , Citometría de Flujo , Humanos , Masculino , Persona de Mediana Edad , Selectina-P/análisis , Agregación Plaquetaria , Inhibidores de Agregación Plaquetaria/uso terapéutico , Trombofilia/sangre , Trombosis de la Vena/etiología , Trombosis de la Vena/prevención & control
6.
J Thromb Haemost ; 3(4): 703-9, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15842355

RESUMEN

BACKGROUND: Patients who have experienced a recent major bleeding episode are usually excluded from clinical studies of venous thromboembolism (VTE) treatment. Therefore, recommendations based on evidence from clinical trials may not be suitable for these patients. The Registro Informatizado de la Enfermedad TromboEmbolica (RIETE) is a multicenter, observational registry designed to gather and analyze data on VTE treatment practices and clinical outcomes in patients with acute VTE. OBJECTIVES: The aim of this analysis was to study outcomes of patients with VTE who had experienced recent major bleeding (< 30 days prior to VTE diagnosis). METHODS: Patients with objectively confirmed symptomatic acute VTE are consecutively enrolled into the RIETE registry. Patient characteristics, details of antithrombotic therapy, and clinical outcomes at 3 months were recorded. RESULTS: Of 6361 patients enrolled up to January 2004, 170 (2.7%) had experienced recent major bleeding: 69 (40.6%) gastrointestinal tract, 60 (35.3%) intracranial, 41 (24.1%) other. The incidences of major bleeding (4.1%) and recurrent pulmonary embolism (PE) (2.4%) were significantly higher in patients with recent major bleeding. Among them, patients with cancer had an increased incidence of major bleeding [odds ratio (OR) 10.0, 95% confidence interval (CI) 2.3, 50; P < 0.001] and fatal PE (OR 4.1, 95% CI 0.98, 17; P < 0.05). CONCLUSIONS: Patients with VTE and recent major bleeding prior to VTE diagnosis (2.7% of total enrolled patients) had poorer clinical outcomes compared with those who had not experienced recent major bleeding. In patients who had recent major bleeding prior to enrollment, those with cancer had a poorer clinical outcome than those without cancer.


Asunto(s)
Hemorragia , Tromboembolia/diagnóstico , Trombosis de la Vena/diagnóstico , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Oportunidad Relativa , Estudios Prospectivos , Sistema de Registros , Factores de Riesgo , Tromboembolia/complicaciones , Tromboembolia/mortalidad , Terapia Trombolítica/métodos , Resultado del Tratamiento , Trombosis de la Vena/complicaciones , Trombosis de la Vena/mortalidad
7.
Clin Appl Thromb Hemost ; 7(1): 72-4, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11190909

RESUMEN

We report on a 19-year-old girl with upper extremity deep vein thrombosis after catheter indwelling whose thrombophilic study disclosed the coexistence of factor V Leiden and the prothrombin G20210A mutation. The family study identified five other members who were also heterozygous for both mutations. This is the first case of upper extremity deep vein thrombosis with the co-inheritance of both genetic defects. It provides further evidence that thrombophilic defects mostly require additional triggering factors to induce a thrombotic event and suggests that in young patients with this venous thrombotic location, a thrombophilic search should be performed even when there are other acquired thrombotic risk factors.


Asunto(s)
Factor V/genética , Genotipo , Protrombina/genética , Trombosis de la Vena/genética , Adulto , Brazo , Catéteres de Permanencia/efectos adversos , Femenino , Heterocigoto , Humanos , Linaje , Mutación Puntual , Trombofilia/sangre , Trombofilia/genética , Trombosis de la Vena/etiología
8.
Rev Esp Cardiol ; 47(7): 490-2, 1994 Jul.
Artículo en Español | MEDLINE | ID: mdl-8090976

RESUMEN

A case of thrombosis in the superior vena cava after two permanent pacemaker implantations is described. Ten years ago the patient had a permanent pacemaker implanted because of disturbances in his cardiac rhythm. Five months later he was readmitted with pacemaker malfunction due to failure of the electrode and a new lead was introduced. In 1989 the generator presented "end of life" and the depleted battery was changed. In February, 1993 he presented a new pacemaker malfunction and thrombosis in the superior vena cava. We suggest that in similar cases the iliac vein approach should be performed and short-term anticoagulant therapy should be considered.


Asunto(s)
Vena Femoral , Marcapaso Artificial , Arritmias Cardíacas/terapia , Falla de Equipo , Vena Femoral/diagnóstico por imagen , Humanos , Vena Ilíaca/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Radiografía , Recurrencia , Vena Subclavia , Trombosis/diagnóstico por imagen , Trombosis/terapia , Vena Cava Superior/diagnóstico por imagen
9.
An Med Interna ; 19(11): 561-6, 2002 Nov.
Artículo en Español | MEDLINE | ID: mdl-12522891

RESUMEN

OBJECTIVE: To evaluate a wide detection of tumor markers practiced during admission for the diagnosis of cancer in patients with idiopathic deep venous thrombosis. MATERIAL AND METHODS: Prospective study including 48 patients with documented DVT who lacked a predisposing cause to DVT. It was determined in serum: carcinoembryonic antigen, alphafetoprotein, CA 19-9, CA 125, beta-2-microglobulin, SCC (squamous cell antigen), NSE (neuron-specific enolase), PSA (prostate-specific antigen) in the males and CA15-3 in the women. The patients were evaluated for cancer during admission and followed up at 6 and 12 months. RESULTS: The age was 65 years. A positive tumor marker at least was detected in 23 patients (48%). A cancer was diagnosed in 8 patients (16%), 4 in the group with elevated tumor markers and 4 in the group with normal tumor markers. We don't find significant differences in cancer incidence between both groups. However, of the 4 cases of cancer diagnosed in the group with elevated markers only 1 was considered true positive since in the others three cases the elevate tumor marker was not appropriated with the cancer diagnosed. Six tumors were diagnosed during admission and two during follow-up period. According to these results was obtained a sensitivity of 12%, a specificity of 52%, a positive predictive value of 5% and a negative predictive value of 75%. CONCLUSIONS: The cancer incidence is similar to previous series. We have found a poor sensitivity, specificity and positive predictive value. However, the negative predictive value was of 75% and the patients who were normals for results of all tumor markers and was asymptomatic during admission hadn't a subsequent cancer diagnosis.


Asunto(s)
Antígenos de Neoplasias , Biomarcadores de Tumor , Neoplasias/diagnóstico , Trombosis de la Vena/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad
10.
Rev Esp Anestesiol Reanim ; 48(8): 387-92, 2001 Oct.
Artículo en Español | MEDLINE | ID: mdl-11674986

RESUMEN

This report of carotid paraganglioma excision in three patients discusses differential diagnosis, preoperative assessment, preoperative embolization of the tumor, monitoring of anesthesia including cerebral oximetry, and postoperative complications. We consider cerebral protection to be essential during carotid paraganglioma surgery. Such protection may be provided by drugs such as sodium thiopental and by temporarily shunting the internal carotid artery. Preoperative angiography is also important for evaluating retrograde circulation through Willis's polygon and to examine the arteries irrigating the tumor. Information thus obtained helps establish the need for presurgical embolization of the tumor, thereby possibly reducing the risks, such as obstructive hematoma that are inherent to the procedure. Finally, in our opinion, full monitoring should include cerebral oximetry so that possible complications can be detected and resolved.


Asunto(s)
Anestesia , Tumor del Cuerpo Carotídeo/cirugía , Adulto , Anestesia/métodos , Tumor del Cuerpo Carotídeo/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Intraoperatorio
11.
J Thromb Haemost ; 9(9): 1761-8, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21676169

RESUMEN

BACKGROUND: Whether the treatment of venous thromboembolism (VTE) with unfractionated heparin (UFH) confers a higher risk of thrombocytopenia than does treatment with low molecular weight heparin (LMWH) remains controversial, and very few data are available from routine clinical practice. OBJECTIVES: We assessed the incidence, risk factors and prognosis of heparin-associated thrombocytopenia (HAT) according to the type of heparin therapy, UFH or LMWH. PATIENTS/METHODS: Data were obtained from the international prospective Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE), which included 25,369 patients with confirmed VTE until February 2009. Among them, 24,401 patients were treated either with UFH or with LMWH, and had available information about the 6-month occurrence of confirmed thrombocytopenia, defined as a platelet count ≤ 150,000 mm(-3) . RESULTS: One hundred and forty-one patients receiving UFH and/or LMWH developed thrombocytopenia within a 6-month period. The incidence of HAT was significantly higher in the UFH group (1.36%, 95% confidence interval [CI] 0.79-2.17) than in the LMWH group (0.54%, 95% CI 0.44-0.64). As compared with LMWH, UFH significantly increased the risk of HAT in female patients (adjusted hazard ratio [HR] 4.90%, 95% CI 2.58-9.31, P = 0.001) but not in male patients (adjusted HR 1.60%, 95% CI 0.64-3.97, P = 0.31); P = 0.027 for comparison. In each gender, the UFH-associated excess risk was confined to patients with VTE unrelated to cancer. The poor prognosis of patients with thrombocytopenia was not influenced by the type of heparin therapy. CONCLUSIONS: In routine clinical practice, treatment of VTE with UFH seems to confer a higher risk of thrombocytopenia than does treatment with LMWH, especially in women and non-cancerous patients.


Asunto(s)
Heparina/efectos adversos , Trombocitopenia/inducido químicamente , Tromboembolia Venosa/tratamiento farmacológico , Anciano , Estudios de Cohortes , Femenino , Heparina de Bajo-Peso-Molecular/efectos adversos , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Sistema de Registros , Factores de Riesgo , Factores Sexuales , Trombocitopenia/epidemiología , Trombocitopenia/etiología
12.
Anal Chim Acta ; 609(2): 160-8, 2008 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-18261510

RESUMEN

Two new, simple and accurate methods for the determination of sulfide (S(2-)) at low levels (microgL(-1)) in aqueous samples were developed. The generation of hydrogen sulfide (H(2)S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H(2)S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was measured at 180.669nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H(2)S enhanced the sulfur signal emission. By setting a gas separator at the end of the reaction coil, reduced sulfur species in the form of H(2)S were removed from the water matrix, thus, interferences could be avoided. Alternatively, the gas separator was replaced by a nebulizer/spray chamber combination to introduce the sample matrix and reagents into the plasma. This methodology allowed the determination of both sulfide and sulfate in aqueous samples. For both methods the linear response was found to range from 5microgL(-1) to 25mgL(-1) of sulfide. Detection limits of 5microgL(-1) and 6microgL(-1) were obtained with and without the gas separator, respectively. These new methods were evaluated by comparison to the standard potentiometric method and were successfully applied to the analysis of reduced sulfur species in environmental waters.


Asunto(s)
Sulfuro de Hidrógeno/química , Espectrofotometría Atómica/instrumentación , Espectrofotometría Atómica/métodos , Sulfuros/análisis , Sulfuros/química , Tampones (Química) , Calibración , Hidrógeno/química , Oxígeno/química , Sensibilidad y Especificidad , Soluciones , Sulfatos/química
13.
J Thromb Haemost ; 6(4): 595-600, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18208535

RESUMEN

BACKGROUND: There is little information on the influence of body mass index (BMI) on mortality in patients with acute venous thromboembolism (VTE). PATIENTS AND METHODS: RIETE is an ongoing registry of consecutive patients with symptomatic, objectively confirmed, acute VTE. We examined the association between BMI and mortality during the first 3 months of therapy. RESULTS: Of the 10 114 patients enrolled as of March 2007: 153 (1.5%) were underweight (BMI < 18.5); 2882 (28%) had a normal weight (BMI 18.5-24.9); 4327 (43%) were overweight (BMI 25.0-30); and 2752 (27%) were obese (BMI > 30). The overweight and obese patients were significantly older, and were less likely to have had cancer, recent immobility or renal insufficiency. After 3 months of therapy their death rates were 28%, 12%, 6.2% and 4.2%, respectively. In multivariate analysis, the relative risks for death after adjusting for confounding variables including age, cancer, renal insufficiency or idiopathic VTE were: 2.1 (95% CI, 1.5-2.7); 1.0 (reference); 0.6 (95% CI, 0.5-0.7); and 0.5 (95% CI, 0.4-0.6), respectively. The rates of fatal pulmonary embolism (2.0%, 2.1%, 1.2% and 0.8%, respectively) also decreased with BMI. There were no differences in the rate of fatal bleeding, but patients who were underweight had an increased incidence of major bleeding complications (7.2% vs. 2.7%; odds ratio, 2.7; 95% CI, 1.4-5.1). CONCLUSIONS: Obese patients with acute VTE have less than half the mortality rate when compared with normal BMI patients. This reduction in mortality rates was consistent among all subgroups and persisted after multivariate adjustment.


Asunto(s)
Índice de Masa Corporal , Sistema de Registros/estadística & datos numéricos , Tromboembolia Venosa/mortalidad , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Anticoagulantes/efectos adversos , Anticoagulantes/uso terapéutico , Argentina/epidemiología , Comorbilidad , Europa (Continente)/epidemiología , Femenino , Hemorragia/inducido químicamente , Hemorragia/mortalidad , Humanos , Israel/epidemiología , Masculino , Persona de Mediana Edad , Neoplasias/epidemiología , Obesidad/epidemiología , Estudios Prospectivos , Embolia Pulmonar/tratamiento farmacológico , Embolia Pulmonar/mortalidad , Insuficiencia Renal/epidemiología , Tromboembolia Venosa/tratamiento farmacológico
14.
Anal Bioanal Chem ; 384(2): 531-41, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16362294

RESUMEN

A new calibration method was developed and applied to inductively coupled plasma atomic emission spectrometry. External calibration was performed as follows. A container was filled with a given volume of deionized (V(p)) water. Then a concentrated standard was introduced at a controlled rate (Q(e)) into the tank by means of a peristaltic pump. The resulting solution was stirred throughout the experiment. Simultaneously, the solution inside the tank was pumped from the vessel to the plasma at a given rate (Q(s)). The signal was continuously recorded. The variation of the concentration of the solution leaving the tank with time was determined by applying a basic equation of stirred tanks. The representation of the emission intensity versus the time and the further conversion of the time scale into a concentration scale gave rise to the calibration line. The best results in terms of linearity were achieved for V(p)=15 cm3, Q(e)=0.6-0.75 ml min(-1) and Q(s)=1-1.2 ml min(-1). Graphs with more than 40 standards were obtained within about 10 min. The results found were not statistically different from those afforded by the conventional calibration method. In addition, the new method was faster and supplied better linearity and precision than the conventional one. Another advantage of the stirred tank was that procedures such as dynamic calibration and standard additions could be easily and quickly applied, thus shortening the analysis time. A complete analysis following these procedures based on the measurement of 30 standards took about 5 min. Several synthetic as well as certified samples (i.e., bovine liver, mussel tissue and powdered milk) were analyzed with the stirred tank by applying four different calibration methodologies (i.e., external calibration, internal calibration, standard additions and a combination of internal standardization and standard additions), with the combination of internal standardization and standard additions being the method that provided the best results. The element concentrations obtained were not significantly different from the actual or certified values.

15.
Anal Bioanal Chem ; 379(5-6): 888-99, 2004 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15197529

RESUMEN

This paper reports characterization of the behavior of five pneumatic micronebulizers based on slightly different designs in inductively coupled plasma atomic-emission spectrometry and mass spectrometry (ICP-AES and ICP-MS). Two nebulizers were used as reference nebulizers, a high-efficiency nebulizer (HEN) and a micromist (MM). They were compared with a commercially available PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) nebulizer and with two new prototypes called the polymeric pneumatic concentric nebulizer (PMN) and the high-solids micronebulizer (HSM). The dimensions of the nebulizers, the gas back-pressure, and the free liquid uptake rates were measured. The study also included tertiary aerosol drop-size distributions, analyte transport rate, and analytical figures of merit, i.e. sensitivities and limits of detection, both in ICP-AES and ICP-MS. Recoveries for two food solid reference materials were also determined. Overall, the results indicated that the PFA and the HEN nebulizers provided the best results. These two nebulizers delivered a higher mass of analyte to the plasma and showed better sensitivies giving lower limits of detection than the PMN, HSM and MM. The results revealed that the liquid prefilming effect occurring before aerosol production in the PFA nebulizer promoted more efficient interaction of liquid and gas, thus affording good results even though gas back-pressure values could be maintained below 3 bar. In contrast, the HEN had to be operated at about 7 bar under the same conditions. Nebulizer design did not have a relevant effect on the recovery, which confirmed that the spray chamber plays an important role in terms of non-spectroscopic interferences.


Asunto(s)
Espectrometría de Masas/instrumentación , Espectrometría de Masas/métodos , Nebulizadores y Vaporizadores , Aerosoles/análisis , Aerosoles/química , Animales , Bivalvos/química , Bovinos , Análisis de los Alimentos/instrumentación , Análisis de los Alimentos/métodos , Hígado/química , Estándares de Referencia
16.
Fresenius J Anal Chem ; 368(8): 773-9, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11227562

RESUMEN

Four different spray chambers were evaluated in ICP-AES at very low liquid flow rates: a double-pass (Scott type), a conventional cyclonic, and two low-volume cyclonic-type spray chambers (i.e., Cinnabar and Genie). A glass concentric pneumatic micro nebulizer (Atom Mist) was used in conjunction with all four chambers. The liquid flow rate was varied from 10 to 160 microL min(-1). The conventional cyclonic spray chamber gave rise to coarser tertiary aerosols, higher analyte and solvent transport rates, higher sensitivity and lower limits of detection than the remaining ones. The low-volume spray chambers afforded analytical figures of merit similar to the double-pass one, despite their very different designs. However, these spray chambers exhibited shorter wash-out times. The matrix effects were significant only for the double-pass. This fact allowed the analysis of reference samples by employing aqueous standards at a minimum level of sample consumption. The recoveries obtained for the cyclonic spray chambers and several certified samples were close to 100%, being always lower in the case of the double-pass spray chamber.

17.
Analyst ; 125(12): 2344-9, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11219080

RESUMEN

The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) as a tool for the analysis of lubricating oils by flame atomic absorption spectrometry (FAAS) was investigated. The effects of the sample oil content [from 10% to 100% (w/w) oil in 4-methylpentan-2-one, IBMK] and the carrier nature (IBMK and methanol) on the characteristics of the aerosols generated, on the analyte transport efficiency and on the analytical figures of merit in FAAS were studied. A pneumatic concentric nebulizer (PCN) was used for comparison. Increasing the oil content increases the viscosity of the sample. With the PCN this gives rise to coarser aerosols, making it impossible to nebulize samples with an oil content higher than 70% (w/w). Using the SBHPPN, the viscosity of the sample scarcely affects the characteristics of the primary aerosols. Hence, the SBHPPN is able, by using the appropriate carrier, to nebulize pure lubricating oils. Among the carriers tested, IBMK is the most advisable because it is fully miscible with all the oil samples. The SBHPPN provides higher sensitivities and lower limits of detection than the PCN. Compared with a method based on organic dilution, the use of the SBHPPN for the direct analysis of lubricating oils by FAAS makes it possible, in addition to increasing the analysis throughput, to detect elements at lower concentrations. Moreover, the SBHPPN provides similar results to those obtained using a previous acid digestion step.

18.
Anal Chem ; 75(1): 111-7, 2003 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-12530826

RESUMEN

A new system has been developed for the determination of total organic carbon (TOC) and inorganic carbon (IC) or total inorganic carbon (TIC) in waters. Only nonvolatile organic compounds can be detected through the present method. The system presented in this work is based on the measurement of the carbon atomic emission intensity in inductively coupled plasma atomic emission spectrometry (ICP-AES). This way, the organic matter does not undergo any preoxidation step. A semiautomatic accessory connected to the spectrometer separates the different carbon fractions (i.e., organic and inorganic). Because most of the solutions used in the present work did not contain suspended solid particles, the actual parameter that was determined was the dissolved organic carbon (DOC). The present system exhibits good sensitivities compared to those provided by conventional TOC and IC determination methods. The limits of detection obtained in the present work have been 0.07 and 0.0007 mg/L C in terms of TOC and IC, respectively. Furthermore, the system is able to handle high-salt-content solutions. This fact suggests that it would be possible to analyze seawater samples, avoiding some of the problems encountered with conventional methods, such as system blocking or interferences. The TOC and IC values found for natural samples are very close to those measured using conventional methods. The ICP-AES method has been successfully used in two interesting applications: (i) monitoring the efficiency of a water treatment plant and (ii) determining the contents of dissolved carbon dioxide, on one hand, and that of carbonate and bicarbonate, on the other, in the same sample.


Asunto(s)
Carbono/análisis , Carbono/química , Espectrofotometría/métodos , Agua/química , Calibración , Dióxido de Carbono/análisis , Sensibilidad y Especificidad , Espectrofotometría/instrumentación , Volatilización
19.
Anal Chem ; 69(17): 3578-86, 1997 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-21639282

RESUMEN

A new thermospray nebulizer based on the absorption of microwave radiation (MWTN) by aqueous solutions of strong acids is presented for the first time. To this end, a given length of the sample capillary is placed inside the cavity of a focused microwave system. A small piece of a narrower capillary tubing is connected at the tip of the sample capillary, outside the microwave cavity, to build up pressure. Drop size distributions of primary aerosols are exhaustively measured in order to evaluate the influence of several experimental variables (microwave power, liquid flow, irradiation length, inner diameter of the outlet capillary, nature and concentration of the acid) on the characteristics of the primary aerosol that are related to the emission signal. These experiments have been performed mainly to increase our understanding of the microscopic process of this new type of aerosol generation. A standard Meinhard nebulizer was employed for comparison. Under the best conditions the entire aerosol volume is contained in droplets smaller than 20 µm compared with 45% of the volume of the aerosol generated by the Meinhard. Hence, higher analyte and aerosol transport rates are to be expected for the MWTN compared with the Meinhard nebulizer. As any highly efficient nebulizer, MWTN requires a desolvation unit. For solutions 0.75 M in strong acid, the new nebulizer improves sensitivity (1.0-2.8 times), limits of detection (1.2-3.0 times), and background equivalent concentration (0.9-2.0 times) as compared to the standard Meinhard nebulizer, features many of the advantages of the conventional thermospray nebulizer, and overcomes some of its drawbacks (MWTN does not show corrosion problems and works at lower pressure, the aerosol characteristics are not modified when the PTFE capillary is replaced).

20.
Arch Esp Urol ; 42(3): 275-7, 1989 Apr.
Artículo en Español | MEDLINE | ID: mdl-2604436

RESUMEN

Although complications post-URS are scant and can usually be resolved by conservative methods, these however, may be potentially severe as in the present case in whom a ureteroiliac fistula was observed during a URS procedure that had been performed to dilate a post-URS stenosis. Previously, extravasation had also occurred. The post-URS complications are briefly described and discussed.


Asunto(s)
Endoscopía/efectos adversos , Fístula/etiología , Arteria Ilíaca , Enfermedades Ureterales/etiología , Fístula Urinaria/etiología , Adulto , Femenino , Humanos , Enfermedades Vasculares/etiología
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