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PubMed2006

Nebulized magnesium sulfate in the management of acute exacerbations of asthma.

OBJECTIVE: To evaluate the efficacy and safety of nebulized magnesium sulfate in the treatment of acute exacerbations of asthma. DATA SOURCES: MEDLINE, EMBASE, and PubMed (all to October 2005) were searched using the key words magnesium, magnesium sulfate, magnesium compounds, nebulise, nebulize, vaporise, vaporize, nebulizers and vaporizers, aerosols, asthma, exacerbation, bronchial spasm, and bronchospasm. STUDY SELECTION AND DATA EXTRACTION: Prospective, randomized, controlled trials that evaluated efficacy and safety endpoints of nebulized magnesium sulfate in the management of acute exacerbations of asthma were included. All studies were evaluated independently by both authors. Efficacy outcomes included pulmonary function, clinical disease severity (as defined by each study), and rate of hospitalization. Safety outcomes were as described by each trial. DATA SYNTHESIS: Six prospective trials met the study criteria. Nebulized magnesium alone failed to demonstrate any benefit compared with beta(2)-agonists alone at improving pulmonary function. In trials in which nebulized magnesium was used as a vehicle for albuterol, there appear to be additional benefits to albuterol therapy in terms of improvements in pulmonary function in a population with mild-to-moderate asthma. The heterogeneous patient populations, study designs, magnesium doses, and the delivery methods preclude the extrapolation of these results to current clinical practice. CONCLUSIONS: The studies included in this review fail to clarify the role of nebulized magnesium sulfate; therefore, this therapy cannot be recommended at this time. Future studies evaluating the role of nebulized magnesium as an adjunct therapy to beta(2)-agonist, anticholinergic, and corticosteroid therapy are necessary to determine whether a clinically relevant benefit of this intervention exists.

Acute Disease↗

PubMed2003

Evaluation of an atmospheric pressure chemical ionization interface for capillary electrophoresis-mass spectrometry.

A simple and inexpensive approach to modify a commercial atmospheric pressure chemical ionization (APCI) interface was proposed for capillary electrophoresis-mass spectrometry (CE-MS). In order to accommodate lower flow rates in the range 1-10 microl/min, both sheath liquid and nebulizing gas were coaxially supplied to the nebulizer as an arrangement of pneumatically assisted electrospray interface. Since this paper focused on the primary study of the modified APCI interface, the performance of the interface was first evaluated by the direct infusion of a reserpine solution. Optimization of several APCI parameters, such as temperature of APCI vaporizer, nebulizing gas flow and APCI corona discharge current, were accomplished. The orifice dimension for the nebulizing gas flow was largely independent of the MS sensitivity when the nebulizing gas flow rate was ca. 0.4 l/min. A successful CE-APCI-MS separation is obtained using the modified APCI interface.

Atmospheric Pressure↗

PubMedDate not supplied

New liquid chromatography/electron ionization mass spectrometry methods in water analysis.

A method to extract and analyze organic compounds from water is presented. A solid phase micro-trap (micro-SPE) directly connected to the micro-analytical column is used. Sensibility and specificity needed for trace analysis are guaranteed by mass spectrometric electron ionization (EI) detection. A new micro-HPLC/EI-MS interface called Capillary-EI (Cap-EI) is described. The ultimate evolution of this interface is also presented: in this extremely simplified interface the analytes are nebulized, vaporized and ionized in the small volume of the ion source. This interface, called Direct-EI, exploits nano- and micro-HPLC columns with a mobile phase flow rates ranging from 0.3 to 1.5 microL/min. Contemporary use of micro SPE, Cap-EI or Direct-EI gives us a powerful technique to identify and quantify organic pollutants at part per billion level (ppb).

Chromatography, High Pressure Liquid↗

PubMed2006

A comparison of slurry sampling electrothermal vaporization and slurry nebulization inductively coupled plasma mass spectrometry for the direct determination of trace impurities in titanium dioxide powder.

A comparison of slurry sampling (SS)-ETV-ICP-MS and slurry nebulization (SN)-ICP-MS for direct determination of trace impurities in titanium dioxide powder is made. The particle size effect, matrix effect and analytical characteristics of SSETV-ICP-MS and SN-ICP-MS are compared. The results have shown that SSETV-ICP-MS has a lower particle size effect and matrix effect compared to SN-ICP-MS. The analytical performance of the two methods reveals that SSETV-ICP-MS and SN-ICP-MS have similar relative detection limits (in the nanogram per liter level); however, the former has a lower absolute detection limit than the latter. Although the precision for SSETV-ICP-MS is a little worse than that for SN-ICP-MS, it is still acceptable for real sample analysis. The two methods were successfully applied for the determination of trace impurities in titanium dioxide powder samples with particle sizes of less than 50 nm, but only SSETV-ICP-MS could be applied for the determination of trace impurities in titanium dioxide powder samples with a particle size of 1 microm.

Journal Article↗

PubMed2005

Low-pressure ICP-AES with electrothermal vaporizer and a pneumatic nebulizer for aqueous sample introduction.

A typical electrothermal vaporization (ETV) using a tantalum was built for low-pressure ICP-AES. The analytical performance of the ETV was tested and compared with that of a PFA pneumatic nebulizer with a double membrane desolvator (DMD). The limits of detection of the ETV were obtained in the range of 3.4 ng to 758 ng for Zn, Cu, Co, Fe, and Mg, while those of the PFA nebulizer were in the range of 53 ppb to 286 ppb. A relative standard deviation (RSD) of 4.3 - 8.5% for ETV was obtained, while 2.15 - 6.84% RSD was found for DMD.

Journal Article↗

PubMed1951

ELECTRESTEEM vaporizers accepted.

Explore the source record for details and available documents.

Nebulizers and Vaporizers↗

PubMed1991

Discriminative stimulus effects of inhaled cocaine in squirrel monkeys.

Squirrel monkeys (N = 4) were trained with food reinforcement to press one of two levers after administration of IV cocaine (0.3 or 1.0 mg/kg) or the other lever after saline. After training, IV cocaine (0.03-3.0 mg/kg) produced dose-related increases in the percentage of responses on the cocaine lever (ED50 = 0.15 mg/kg). Cocaine delivered IM also produced dose-related increases in cocaine-appropriate responding (ED50 = 0.32 mg/kg), but was approximately half as potent as IV cocaine. Similar relative potency relations were obtained for decreases in response rates produced by cocaine. Prior to some sessions subjects were placed in a Plexiglas chamber and exposed for 60 s to cocaine vapor created with an ultrasonic nebulizer. Exposure to vapor from cocaine solutions (1.0-30.0 mg/ml) produced concentration-dependent increases in cocaine-appropriate responding and decreases in response rates. Exposure to vapor from a 30 mg/ml concentration produced virtually exclusive cocaine-appropriate responding. Concentration-effect curves for inhaled cocaine were similar to dose-effect curves obtained when cocaine was administered by the other routes. The time course of the minimally effective concentration of inhaled cocaine was compared to that of the minimally effective doses of systemically administered cocaine. Inhaled cocaine had a duration of action longer than IV cocaine. The results indicate that inhaled cocaine vapor has effects qualitatively similar to those of IV cocaine, and may have a duration of action longer than that of an IV cocaine dose producing a similar degree of drug-appropriate responding.

Administration, Inhalation↗

PubMed1989

Liquid chromatographic-atmospheric pressure ionization mass spectrometric analysis of toremifene metabolites in human urine.

A liquid chromatographic-atmospheric pressure ionization mass spectrometric method has been developed for the analysis of toremifene metabolites in human urine after oral administration. This ionization source is a useful device for studying metabolites of toremifene because the total effluent from high-performance liquid chromatography is fed through an interface with a direct heating nebulizer and vaporizer at atmospheric pressure. To obtain good sensitivity the use of the right mobile phase is very important: ammonium acetate in methanol in the case of toremifene and its metabolites. Four unconjugated and three glucuronide-conjugated metabolites were detected in human urine. The majority of these were new and distinguishable from known metabolites.

Antineoplastic Agents↗

PubMed2006

Capillary electrochromatography coupled to atmospheric pressure photoionization mass spectrometry for methylated benzo[a]pyrene isomers.

Benzo[a]pyrene, one of the most carcinogenic PAHs, has 12 monomethylated positional isomers (MBAPs). A strong correlation between the carcinogenicity of these isomers and methyl substitution has been reported. In this study, on-line coupling of capillary electrochromatography (CEC) and atmospheric pressure photoionization mass spectrometry (APPI-MS) provides a unique solution to highly selective separation and sensitive detection of MBAP isomers. The studies indicated that APPI provides significantly better sensitivity compared to electrospray ionization and atmospheric pressure chemical ionization modes of MS. A systematic investigation of APPI-MS detection parameters and CEC separation is established. First, several sheath liquid parameters (including type and concentration of volatile buffers, type and content of organic modifiers, use of dopants and inorganic/organic additives, and sheath liquid flow rate) and APPI-MS spray chamber parameters (capillary voltage, vaporizer temperature, nebulizer pressure) were found to have effects on detection sensitivity as well as the profile of mass spectrum. For example, when ammonium acetate was replaced with acetic acid in the sheath liquid, the MS signal was enhanced as much as 90% and the formation of ammonia adduct was effectively suppressed. Next, the separation of MBAP isomers was conducted on internal tapered columns packed with polymeric C18 stationary phase. With the use of a mobile phase consisting of slightly higher acetonitrile content (90%,v/v) and a small amount of tropylium ion, the analysis times were significantly shortened by 20 min without compromising the resolutions between the isomers. Finally, quantitative aspects of the CEC-APPI-MS method were demonstrated using 7-MBAP as the internal standard. The calibration curves of three of the most carcinogenic isomers, namely, 1-MBAP, 3-MBAP, and 11-MBAP, showed good linearity in the range of 2.5-50 microg/mL with a limit of detection at 400 ng/mL.

Atmospheric Pressure↗

PubMed1979

[Patient monitoring].

The main problems of monitoring patients on prolonged artificial respiration are discussed. These are: uninterrupted technical control of the respirator and of its clinical effects; continuous observation of the functioning of tubes, vaporizers and nebulizers; adequate tracheobronchial clearance and breathing therapy is absolutely compulsory. Intensive care units are classified into three categories according to their monitoring and surveillance capacities. The minimum, which corresponds to category I, should be performed by every intensive care unit. Category III includes additional computerized intensive care. The most important parameter for monitoring pulmonary function is blood gas analysis, which has been improved by the introduction of continuous arterial pO2 registration. Haemodynamic control serves for detection of arrhythmias and changes in pump function. The determination of pulmonary shunt flow (Qs/Qt) and of the ratio of dead space to tidal volume (VD/VT) impart information on the overall function of both systems (category II). A nomogram to simplify the calculation of pulmonary shunt is proposed which aggregates the factors contributing most to pulmonary shunt in acute respiratory failure. Its results deviate less than 1% from the calculated values if PCO2 ranges between 32 and 52 mm Hg and the error does not exceed 1.5 per cent with a PCO2 up to 82 mm Hg, unless it is combined with a very low Hb and high mixed venous saturation.

Blood Gas Analysis↗

PubMed1954