SEARCH · Search PubMed

Results for “AEROSOLS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed2002

Evaluation of a tractor cab using real-time aerosol counting instrumentation.

Aerosol instrumentation was used to evaluate air infiltration into tractor cabs that are used to protect the agricultural worker during pesticide applications. Preliminary surveys were conducted on three different manufactured agriculture enclosures. The results of these preliminary surveys indicated that aerosols are entering the cab through leak sources or are being generated inside the cab. These results identified the need for in-depth field evaluations of tractor cabs to identify any leak sources. To evaluate the ability of tractor cabs to reduce operator air contaminant exposure, field evaluations were conducted on two tractor cabs. Specifically, we evaluated: 1) the particle size distribution and the effectiveness of the filter system; and 2) air infiltration into the cab. These evaluations were also conducted to demonstrate the ease and practicality of using optical particle counters to evaluate the ability of cabin filtration systems. Pesticide particle size distribution during an air blast spray operation was also evaluated during the study. The field tests were conducted on a John Deere 7000 series tractor cab (tractor manufacturer's cab) and a Nelson spraycab (retrofit cab). Both cabs were equipped with high efficiency particulate air (HEPA) filter media which were assumed to be 99.97 percent efficient at removing the test aerosol, atmospheric condensation nuclei. Thus, the major source of aerosols inside the cab was assumed to be leakage around filters at the seals. Using a portable dust monitor (PDM), the ratio of the outside to inside aerosol measurements was used to calculate a cab protection factor. During the evaluations, one PDM was placed inside the tractor cab (near the tractor operator) and one PDM was placed outside (near the air intake) to count particles. During the evaluations, the instruments were switched to prevent instrument bias from affecting the findings. The ratio of the two measurements (i.e., protection factor = outside concentration / inside concentration) was used to calculate how efficient the tractor cab was at removing aerosols. The John Deere cab was more than 99 percent efficient at removing aerosols larger than 3.0 microm in diameter and had protection factors greater than 260 for particles larger than 3.0 microm (indicated by the PDM results). The Nelson cab was more than 99 percent efficient at removing aerosols larger than 3.0 microm in diameter and had protection factors greater than 200 for particles larger than 3.0 microm (indicated by the PDM results). For aerosols smaller than 1.0 microm in diameter (indicated by a PortaCount Plus instrument), the John Deere cab provided a mean protection factor of 43 and the Nelson cab provided a mean protection factor of 16. The results from this study indicate that tractor cabs can be effective at removing different size aerosols depending on the seals and filters used with the enclosure. This study has also demonstrated the practical use of real-time aerosol counting instrumentation to evaluate the effectiveness of enclosures and to help identify leak sources. The method used in this study can be applied to various cabs used in different industries including agriculture, construction, and manufacturing.

Aerosols↗

PubMed1993

Effects of exposure to sulfuric acid-aerosol on airway responsiveness in guinea pigs: concentration and time dependency.

We investigated the concentration and time dependency of the effects of exposure to sulfuric acid (H2SO4) aerosol on airway responsiveness. Two hundred and sixteen male Hartley guinea pigs were used. The animals were divided into 3 groups (n = 72/group), with 1 group being exposed to filtered air and the other 2 to 1.0 mg/m3 or 3.2 mg/m3 H2SO4 aerosol. In each group, the animals were divided into 4 subgroups (n = 18/subgroup), with exposure terms of 3 d (24 h/d), 7 d, 14 d, and 30 d. Specific airway resistance (SRaw) under room air (SRaw0) and airway responsiveness were determined 1 wk before the beginning of exposure and on the day of termination of the exposure. Specific airway resistance values under room air (SRaw0) prior to and after exposure were compared. There was no significant change in SRaw0 after the exposure to filtered air, 1.0 mg/m3, or 3.2 mg/m3 H2SO4 aerosol. Our results also showed that exposure to filtered air or 1 mg/m3 H2SO4 aerosol did not cause any significant change in airway responsiveness to inhaled histamine aerosol, expressed as the effective concentration of histamine (EC200His) that produced a doubling of SRawNaCl (SRaw after exposure to aerosol of 0.9% NaCl saline). On the contrary, exposure to 3.2 mg/m3 H2SO4 aerosol induced transient airway hyporesponsiveness after a 3-d exposure [EC200His prior to and after exposure: 1.35 +/- 0.28 and 2.23 +/- 0.22 mM (p < .01), respectively] and then transient hyperresponsiveness after a 14-d exposure [EC200His prior to and after exposure: 1.65 +/- 0.21 and 0.95 +/- 0.23 mM (p < .01), respectively]. Overall, the present results revealed that (1) 1.0 mg/m3 or 3.2 mg/m3 H2SO4 aerosol had no significant effect on SRaw0 during a 30-d exposure period, (2) a high concentration (3.2 mg/m3) of H2SO4 aerosol affected airway responsiveness during the 30-d exposure, while a low concentration (1.0 mg/m3) of H2SO4 aerosol did not, and (3) the effect of exposure to 3.2 mg/m3 H2SO4 aerosol on airway responsiveness was transient and stimulatory or inhibitory, depending on the duration of exposure.

Administration, Inhalation↗

PubMed1985

Emission of ink aerosol from ink-jet recorders.

As a follow-up of two patients found to be allergic to EKG*ink, a study was made, using spectrophotometric and light microscopic methods, of the factors influencing the emission of ink aerosol from ink-jet recorders used in electrocardiographs. Ink aerosol concentrations were only detectable by spectrophotometry under extreme conditions. However, the light microscopic method was sufficiently sensitive. At the slow paper speeds normally used (10-25 mm/sec) and under normal working conditions, the concentration of ink aerosol near the recorder was less than 0.1 microgram/m3; but aerosol emission increased exponentially with increasing ink pressure, i.e. increasing paper speed. At the highest paper speed studied (200 mm/sec), the aerosol concentration 36 cm from the ink nozzles was about 65 micrograms/m3. An increase in the distance from the ink nozzles to the chart paper resulted in a decrease in ink aerosol emissions. Aerosol dissipation was decreased by local exhaust ventilation of the ink-jet recorder. However, a protective shield designed to catch emitted ink aerosol only reduced the aerosol concentration at the measuring point at slow paper speeds. At higher paper speeds, the concentration increased. The average ink aerosol concentration near modern electrocardiographs is low, but some EKG operations may result in high peak concentrations. The formation of ink aerosol could be considerably reduced by changing the rheologic properties of the ink.

Aerosols↗

PubMed1990

Sampling and interpretation errors in aerosol monitoring.

The aerosol recorded by simple filter collection or by sophisticated instrument aerosol monitoring may differ considerably from the original, unsampled aerosol. Through use of particle-sizing instruments and computer modeling, the potential biases in sampling, display, and interpretation are demonstrated. The aerosol-size distribution and, therefore, the reported number or mass concentration may be affected by the characteristics of the sampling inlet, the transport to the sensor and the sensor itself. The particle count in specific size ranges determines the precision of the registered particle-size distribution, depending on the weighting chosen. The type of display, by histograms or cumulative plot, focuses on different aspects of the size distribution, and the calibration of the aerosol monitor may modify it further. Particle-size classification to simulate a specific region of the human respiratory system may be achieved through inertial classification or the sensitivity characteristics of the aerosol sensor. Aerosol monitors using passive sampling register the same aerosol-size distribution as active ones, if the aerosol is transported to the sensor with the same efficiency as in the active mode. The sources of various types of errors are presented using computer simulations of typical aerosol-size distributions, often combined with measurements found in the literature. Presentation of these errors in graphical format allows the health professional to estimate more accurately the health implications of aerosol measurements.

Aerosols↗

PubMed2004

Size distribution and speciation of chromium in paint spray aerosol at an aerospace facility.

Spray painters are potentially exposed to aerosol containing Cr(VI) via inhalation of chromate-based paint spray. Two field studies were conducted at an aerospace facility to determine the size distribution and speciation of Cr(VI) in paint spray aerosol. Sampled paint products consisted of sparingly soluble strontium chromate in an epoxy resin matrix, a matrix generally known for its durability and toughness. Personal aerosol samples were collected using Sierra Marple personal cascade impactors and analyzed for Cr(VI) and total Cr. The size distribution of total Cr particles in the paint aerosol had a Mass Median Aerodynamic Diameter (MMAD) of 7.5 mum [Geometric Standard Deviation (GSD = 2.7 mum)] in both field studies. The MMAD of Cr(VI) particles was 8.5 mum (GSD = 2.2 mum). Particles >2 mum constituted 90% or more of the total Cr and the Cr(VI) mass, in all sampled paint aerosols and were lognormally distributed. The target site for respiratory deposition of Cr in the aerosol was estimated based on the mass distribution of Cr according to particle size. On an average, 62% of the Cr and Cr(VI) mass in the paint aerosol consisted of particles >10 mum. This study showed that 71.8% of Cr(VI) mass in paint spray aerosol potentially inhaled by a spray painter may deposit in the head airways region. Only 2.0 and 1.4% of Cr(VI) mass in the paint aerosol may potentially deposit in the alveolar and tracheobronchial region, respectively. The ratio of Cr(VI) mass to total Cr mass was determined in bulk paint and the data indicate that Cr was predominantly in the Cr(VI) valence state, before spraying. The ratio of Cr(VI) mass to total Cr mass was also determined in paint aerosol samples. The data indicated that there was a reduction of Cr(VI) regardless of Cr aerosol particle size. Cr(VI) reduction occurred most likely during the 8 h sample collection time period. These findings are in agreement with the findings that observed Cr(VI) reduction during collection of airborne Cr(VI) in samples of chromic acid mist. The use of Cr(VI) stabilizing sampling media and the storage of samples at lower temperatures (4 degrees C ) during and after sampling may avoid the underestimation of Cr(VI).

Aerosols↗

PubMed1970

Experimental technique for studying aerosols of lyophilized bacteria.

An experimental technique is presented for studying aerosols generated from lyophilized bacteria by using Escherichia coli B, Bacillus subtilis var. niger, Enterobacter aerogenes, and Pasteurella tularensis. An aerosol generator capable of creating fine particle aerosols of small quantities (10 mg) of lyophilized powder under controlled conditions of exposure to the atmosphere is described. The physical properties of the aerosols are investigated as to the distribution of number of aerosol particles with particle size as well as to the distribution of number of bacteria with particle size. Biologically unstable vegetative cells were quantitated physically by using (14)C and Europium chelate stain as tracers, whereas the stable heat-shocked B. subtilis spores were assayed biologically. The physical persistence of the lyophilized B. subtilis aerosol is investigated as a function of size of spore-containing particles. The experimental result that physical persistence of the aerosol in a closed aerosol chamber increases as particle size is decreased is satisfactorily explained on the bases of electrostatic, gravitational, inertial, and diffusion forces operating to remove particles from the particular aerosol system. The net effect of these various forces is to provide, after a short time interval in the system (about 2 min), an aerosol of fine particles with enhanced physical stability. The dependence of physical stability of the aerosol on the species of organism and the nature of the suspending medium for lyophilization is indicated. Also, limitations and general applicability of both the technique and results are discussed.

Aerosols↗

PubMed1991

Inhalation of an alkaline aerosol by subjects with mild asthma does not result in bronchoconstriction.

Although it is recognized that inhalation of acid aerosols by subjects with asthma can cause bronchoconstriction, the effects of the inhalation of an alkaline aerosol are unknown. When supplemental inflatable restraints (automobile air bags) are deployed an alkaline aerosol is released. This aerosol is composed of particles of sodium carbonate and sodium bicarbonate with some sodium hydroxide. The mass median aerodynamic diameter (MMAD) of the aerosol is approximately 1 micron, and the pH of the aerosol is 9.8 to 10.3. A group of 14 volunteer male subjects with mild asthma inhaled increasing concentrations of this aerosol for 20-min periods of mouth-only tidal ventilation. Pulmonary function tests were performed at baseline (preexposure), after inhalation of room air alone (control), and after each period of inhalation of the aerosol. A total of 5 subjects inhaled aerosols at nominal concentrations of 10, 20, and 40 mg/m3, whereas 11 subjects inhaled aerosols concentrations of approximately 30, 60, and 120 mg/m3. The mean changes in FEV1 and specific airways resistance (SRaw) for the 11 subjects who inhaled the higher concentrations (average highest concentration 126.6 +/- 7.5 mg/m3, mean +/- SEM) were -1.4 +/- 1.9 and +17.5 +/- 8.5%, respectively. Neither change in lung function was clinically or statistically significant. We conclude that the inhalation of relatively high concentrations of this alkaline aerosol by subjects with mild asthma does not result in bronchoconstriction.

Adolescent↗

PubMed2006

Hypotension following treatment with aerosolized colistin in a patient with multidrug-resistant Pseudomonas aeruginosa.

OBJECTIVE: To report a case of a man who developed temporary hypotension after aerosolized colistin administration. CASE SUMMARY: A 62-year-old Arab male was admitted to the intensive care unit for respiratory failure and septic shock. Simultaneous therapy using intravenous and aerosolized colistin was initiated for the management of multidrug-resistant Pseudomonas aeruginosa. A significant but transient drop in blood pressure occurred when aerosolized colistin was introduced. However, when it was stopped, but intravenous administration was continued, no hypotension was observed. Moreover, the combined use of aerosolized amikacin with intravenous colistin did not significantly affect blood pressure. DISCUSSION: It is widely accepted that aerosolization allows safe administration of colistin in the absence of significant systemic adverse effects. However, in our patient, hypotension was observed with aerosolized colistin, but not with the systemic formulation. The lack of adverse effects with administration of aerosolized amikacin in this patient demonstrates the safety of the aerosolization technique. Use of the Naranjo scale indicated a probable relationship between hypotension and aerosolized colistin administration. CONCLUSIONS: This case suggests that hypotension may be induced with administration of aerosolized colistin. Although this effect is rare, clinicians should be aware that hypotension may develop in critically ill patients following aerosolized colistin treatment.

Administration, Inhalation↗

PubMed1999

Assessing the clinical effectiveness of an aerosol reduction device for the air polisher.

BACKGROUND: Because of the growing concern of the infectious nature of aerosols produced by air polishers, the Centers for Disease Control and Prevention and the American Dental Association have made recommendations to minimize dental aerosols. In addition, a device was developed in 1997 to reduce the aerosol generated during air polishing. METHODS: The authors conducted a blinded clinical study to determine the effectiveness of an aerosol reduction device during air polishing. All 30 subjects underwent two minutes of air polishing, one with the aerosol reduction device on one side of the mouth and one without the device on the opposite side. Microbial samples were collected on blood agar plates positioned 12 inches from the subject's mouth and from one plate attached to the dental hygienist's face mask. The sample plates were then inverted and incubated for three days at 37 C. RESULTS: Using the paired t-test, the authors found that the air polisher without the aerosol reduction device generated a significantly greater mean quantity of colony-forming units, or CFUs, 12 inches from the subject's mouth (mean +/- standard deviation, 148.00 +/- 145.00 CFUs) than the air polisher with the aerosol reduction device (20.10 +/- 53.90 CFUs) (P < .0001). In addition, the air polisher without the aerosol reduction device generated a significantly greater number of CFUs on the face mask plate (40.90 +/- 33.80 CFUs) than the air polisher with the aerosol reduction device (8.80 +/- 15.10 CFUs) (P < .0001). CONCLUSION: The data suggest that the aerosol reduction device is effective in reducing the number of microorganisms generated during air polishing. CLINICAL IMPLICATIONS: Air polishing with the aerosol reduction device may decrease the potential for disease transmission.

Adult↗

PubMed2003

Aerosol gene therapy with PEI: IL-12 eradicates osteosarcoma lung metastases.

PURPOSE: We determined whether polyethylenimine (PEI), a polycationic DNA carrier, can be used to deliver the interleukin (IL) 12 gene by aerosol to treat established osteosarcoma (OS) lung metastases in a nude mouse model. EXPERIMENTAL DESIGN: Tumor response was assessed using our OS lung metastases model. Treatment with aerosolized PEI containing the murine IL-12 gene (PEI:IL-12; 600 microl PEI and 2 mg IL-12) was given twice weekly for 5-6 weeks. RESULTS: Aerosol therapy for 2 weeks resulted in high expression of both the p35 and p40 subunits of IL-12 in the lungs but not in the livers of mice. Peak IL-12 mRNA expression was seen 24 h after a single aerosol PEI:IL-12 treatment. This expression gradually decreased with continued detection for up to 7 days. IL-12 protein was not detectable in plasma even after 6 weeks of aerosol therapy. The number of lung metastases in mice treated with aerosol PEI:IL-12 was decreased significantly (median, 0; range, 0-33) compared with mice that received PEI alone (median, 37.5; range, 11-125; P = 0.002). Nodule size was also significantly smaller in the aerosol PEI:IL-12 group with 87% of the nodules measuring 1 mm. Weekly aerosol PEI:IL-12 therapy was as effective as twice weekly therapy. CONCLUSIONS: Aerosol therapy resulted in selective gene expression and protein production in the tumor area. Aerosol PEI:IL-12 may avoid the systemic toxicities described previously in patients treated with i.v. IL-12. Because OS metastasizes almost exclusively to the lung, aerosol PEI:IL-12 therapy may provide a therapeutic option, which may be especially valuable.

Aerosols↗

PubMed2006

Physicochemical properties of nitrate aerosols: implications for the atmosphere.

As aerosols, such as sea salt and mineral dust, are transported through the atmosphere they undergo heterogeneous reactions with nitrogen oxides to form nitrate salts. The nitrate salt can have quite different physicochemical properties than the original aerosol, resulting in an aerosol that will markedly differ in its climate impact, heterogeneous chemistry, and photoactivity. In this Feature Article, we will review some aspects of the importance of aqueous nitrate aerosols as well as describe a new multi-analysis aerosol reactor system (MAARS) that is used to measure the physicochemical properties of these atmospherically relevant aerosols. Here we show measurements of the hygroscopic properties, cloud condensation nuclei activity, and FTIR extinction of nitrate salt aerosol. In particular, we have measured the hygroscopic growth of 100 nm size-selected nitrate particles including NaNO3, Ca(NO3)2, Mg(NO3)2, and a 1:1 mixture of Ca(NO3)2 and Mg(NO3)2 as a function of relative humidity (RH) at 298 K. Using Köhler theory, we have quantified the water content of these particles with increasing RH. FTIR extinction measurements of the full size distribution of each of the nitrate aerosols are analyzed to yield information about the local solvation environment of the nitrate ions and the long-wavelength light scattering of the particles at different RH. Furthermore, we have measured and compared the cloud condensation nuclei (CCN) activity of CaCO3, a large component of mineral dust aerosol, and Ca(NO3)2, a product of atmospherically aged CaCO3 through reaction with nitrogen oxides, at supersaturations from 0.1% to 0.9%. These quantitative physicochemical data are needed if we are to better understand the chemistry as well as the climate effects of atmospheric aerosols as they are entrained, transported, reacted, and aged in the atmosphere. Our studies here focus on aqueous nitrate salts, the products of the reaction of nitrogen oxides with sea salt and mineral dust aerosol.

Journal Article↗

PubMed1993

Occupational exposure to 4,4'-bipyridyl vapor and aerosol during paraquat manufacturing.

The mass concentrations of both vapor and aerosol phases of 4,4'-bipyridyl were determined by a glass fiber filter and an XAD-2 tube in a paraquat factory. The size distributions of 4,4'-bipyridyl aerosols and particles < 10 microns were measured by a six-stage cascade impactor. The mass concentrations of 4,4'-bipyridyl aerosols were in the range of 81.9 to 159.9 mg/m3 with an average 4,4'-bipyridyl vapor mass concentration of 3.1 mg/m3 at the top of the open tank. On the average, the mass ratio of vapor phase to aerosol phase of 4,4'-bipyridyl was 0.025. Therefore, the aerosol phase is the major form of 4,4'-bipyridyl exposure to the workers in this environment. From the 4,4'-bipyridyl concentrations measured by the sampling systems of an XAD-2 tube alone and a filter followed by an XAD-2 tube, the 4,4'-bipyridyl aerosol collection efficiency of the XAD-2 tube was found to be approximately 50%. The average mass concentrations of less than 10 microns aerosols and 4,4'-bipyridyl aerosol in the occupational environment were 0.42 mg/m3 and 1.26 micrograms/m3, respectively. The mass median aerodynamic diameter (geometric standard deviation) of particles < 10 microns and 4,4'-bipyridyl aerosol are 3.50 microns (2.35) and 3.47 microns (2.58), respectively. The major mass fraction of 4,4'-bipyridyl aerosol occurred in the 3.3-5.8 microns size range. The enclosure efficiencies of a hood cover attached to a suction tube were found to be 88% and 82% for both aerosol and vapor phases of 4,4'-bipyridyl, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗

PubMed2004

Dose response to aerosolized perflubron in a neonatal swine model of lung injury.

Aerosolized perfluorocarbon (PFC) improves gas exchange, lung mechanics, and pulmonary artery pressure. The objective of this intervention was to study the dose-response effect to aerosolized perfluorooctylbromide (PFOB; perflubron, LiquiVent, Alliance Pharmaceutical Corp.) in surfactant-depleted piglets. After induction of lung injury by saline lavage, 25 newborn piglets were randomly assigned to receive 0, 1.25, 2.5, 5.0, or 7.5 mL/kg aerosolized PFOB per hour. A 2-h therapy period was followed by a 3-h observation period. In all animals, respiratory support was performed with intermittent mandatory ventilation. After aerosol treatment and 3 h of observation, arterial oxygen pressure was similarly improved in the 2.5-, 5.0-, and 7.5-mL. kg(-1). h(-1) aerosol-PFOB groups and higher compared with the 1.25-mL. kg(-1). h(-1) aerosol-PFOB (P < 0.01) and the control groups (P < 0.001). Compared with the control group, arterial carbon dioxide pressure was significantly reduced with 2.5-, 5.0-, and 7.5-mL. kg(-1). h(-1) aerosol-PFOB (P < 0.001). Treatment with 1.25 mL. kg(-1). h(-1) aerosol-PFOB did not significantly affect arterial carbon dioxide pressure. The 20% terminal dynamic compliance/dynamic compliance was significantly improved in the groups that received 2.5, 5.0, and 7.5 mL. kg(-1). h(-1) aerosol-PFOB compared with control animals. Mean pulmonary artery pressure was lower after therapy with 5.0 and 7.5 mL. kg(-1). h(-1) aerosol-PFOB (P < 0.01) than in the control group. IL-1beta gene expression in lung tissue was significantly reduced with PFOB 1.25 mL. kg(-1). h(-1). In summary, aerosolized PFOB improved terminal dynamic compliance, pulmonary gas exchange, and pulmonary artery pressure in a dose-dependent manner. In terms of oxygenation and lung mechanics, the optimum dose was between 2.5 and 5 mL. kg(-1). h(-1).

Animals↗

PubMed2006

The functional benefit of anti-inflammatory aerosols in the lung periphery.

BACKGROUND: The target of anti-inflammatory therapy in asthma is thought to be situated, at least partly, in the lung periphery, and inhaled steroid aerosols are being engineered to reach it. However, the potential effect of such aerosols cannot be fully evaluated by conventional lung function tests because these are insensitive to peripheral lung structure. OBJECTIVE: A prospective cohort study was conducted to investigate whether ultrafine steroid aerosols can elicit a response in the lung periphery, using a validated multibreath washout technique that can distinguish acinar from conductive lung zone function. METHODS: In 30 stable patients with asthma with a wide range of disease severity (FEV(1) 27% to 108% predicted), we assessed conductive and acinar airway function abnormality at baseline, with patients on a standard dry powder steroid aerosol and after switching them to an ultrafine steroid aerosol. RESULTS: Only in those patients with abnormal acinar airway function at baseline (n = 16) did acinar heterogeneity show a consistent improvement after switching to an ultrafine steroid aerosol; the improvement was also correlated with baseline acinar heterogeneity (r = -0.67; P = .007). Although all patients with asthma also presented conductive airway abnormality at baseline, no changes were observed in this lung zone with the switch to the ultrafine aerosol (P > .1). CONCLUSION: Among stable patients with asthma, those with acinar lung zone abnormality at baseline have the potential to receive functional benefit from an ultrafine steroid aerosol. Clinical studies comparing the efficacy of steroid aerosols targeted to the deep lung should at least include a measurement of peripheral lung zone function. CLINICAL IMPLICATIONS: A new noninvasive measure of small airways function reveals why, and for which particular patients with asthma, small steroid aerosol particles can be of therapeutic use.

Adolescent↗

PubMed1987

Cough and wheezing from beclomethasone dipropionate aerosol are absent after triamcinolone acetonide.

STUDY OBJECTIVE: To test the hypothesis that patients with asthma who develop cough and wheezing after the use of beclomethasone aerosol would have a better tolerance for triamcinolone aerosol. DESIGN: Randomized, double-blinded, crossover trial. SETTING: Pulmonary function laboratory. PATIENTS: Volunteer sample of 24 patients attending an asthma clinic who had developed cough, with or without wheezing, after inhaling beclomethasone aerosol. All patients completed the study. INTERVENTIONS: Aerosols were used in habitual manufacturers' preparations and canisters, but both were administered in three puffs through the delivery system used for triamcinolone. The preparations differed in drug (beclomethasone dipropionate or triamcinolone acetonide), propellant (trichloromonofluoromethane and dichlorodifluoromethane, or dichlorodifluoromethane alone, respectively) and dispersant (oleic acid or dehydrated alcohol, respectively). PATIENTS inhaled three puffs of one aerosol on one day and three of the other on the next. MEASUREMENTS AND MAIN RESULTS: Forced expiratory volume in one second (FEV1) was measured before and after each aerosol application. The FEV1 decreased a mean of 17.7% from baseline after inhalation of beclomethasone, and 0.8% after triamcinolone (difference, 16.9; 95% confidence limits, 12.36 to 21.34; p less than 0.001). Coughs were counted after each puff. The mean number of coughs after beclomethasone aerosol inhalation was 35.8, and after triamcinolone, 0.5 (difference, 35.3; 95% confidence limits, 22.62 to 47.98, p less than 0.001). CONCLUSIONS: Asthmatic patients who are unable to inhale beclomethasone aerosol due to cough or wheezing can inhale triamcinolone aerosol without difficulty. Our investigation does not determine the exact cause of the coughing and wheezing with the beclomethasone aerosol, but we suspect the dispersant as the source.

Adult↗

PubMedDate not supplied

Respiratory peripheral chemosensory irritation, acute and repeated exposure toxicity studies with aerosols of triethylene glycol.

The potential for adverse effects from exposure to respirable aerosols of triethylene glycol (TEG: CAS Number 112-27-6) was investigated by a peripheral chemosensory irritation study, and by acute and repeated exposure toxicity studies. The sensory irritation study, conducted with male Swiss Webster mice, showed an exposure concentration-related depression of breathing rate that allowed the calculation of an RD50 of 5140 mg m(-3). In an acute study male and female Sprague Dawley rats were exposed whole body to aerosols of TEG up to 6730 mg m(-3) for 4 h. No mortalities occurred at this high concentration, but unexplained mortality occurred in female rats at 5230 mg m(-3) at 2-3 days postexposure. Two repeats of the 5230 mg m(-3) exposure did not cause mortality. Signs at 6730 and 5230 mg m(-3) were limited to those of irritancy. For a 9 day repeated exposure study rats were exposed whole body to 0, 494, 2011 and 4824 mg m(-3) TEG aerosols for 6 h day(-1). Mortalities occurred at 4824 mg m(-3) between exposure days 2 and 5. Nonspecific indications of toxicity at 2011 mg m(-3) were signs of irritation, decreased body weight and increased food and water consumption; evidence of hepatic dysfunction was indicated by increased serum alkaline phosphatase and alanine aminotransferase activities, but liver histology was normal. Fluid imbalance was suggested by increases in water consumption, blood urea nitrogen, relative kidney weight and urine volume, with decreased urine osmolality, pH and N-acetyl-beta-D-glucosaminidase activity. At 494 mg m(-3) there were minimal signs of irritation, increased water consumption and slightly increased alkaline phosphatase; histology of the kidney was normal. Thus, in this 9 day repeated aerosol whole body exposure study a No-Observed-Effect-Level (NOEL) could not be established. Since preening of the fur at these high aerosol concentrations exposures might have led to a confounding factor from the resultant oral intake, another 9 day repeated aerosol study was conducted, but by nose-only exposure of rats for 6 h day(-1) to TEG aerosol concentrations of 0, 102, 517 and 1036 mg m(-3). In this study there were no clinical signs, no effects on food and water consumption, and no biochemical or histological evidence of hepatorenal dysfunction. By the end of the exposure period, male and female rats of the 1036 mg m(-3) group had body weights lower than those of the controls, but not with statistical significance. Since there were no statistically significant effects on any monitors, 1036 mg m(-3) is considered to be a threshold for toxicity by nose-only exposure to TEG aerosol. The findings indicate that exposure to a respirable aerosol is not acutely harmful, but may cause sensory irritant effects. Repeated exposure to high concentrations of TEG aerosols may be harmful, particularly if there are contributions from additional routes of exposure.

Administration, Inhalation↗

PubMed2001

Enhanced efficiency of electrostatically charged insecticide aerosols.

The bioefficacy of a standard domestic aerosol insecticide has been compared with that of a similar spray in which the droplets were electrostatically charged. The aerosol was charged without the need for an external power supply, by enhancing natural charge separation processes that occur during atomisation. The charge-to-mass ratio achieved was 1.1 x 10(-4) C kg-1, compared with 2.2 x 10(-5) C kg-1 for the standard aerosol. Efficiency was assessed for insects in free flight. A direct space-spray application method was used to study the bioefficacy of these aerosols on houseflies, Musca domestica, and an indirect space-spray method on houseflies and mosquitoes, Culex quinquefasciatus. Two levels of concentration of active ingredients were compared. At low concentrations of 1.57 g kg-1 of bioallethrin and 0.29 g kg-1 of bioresmethrin, the charged aerosol achieved a significant reduction in KDT50 (time at which 50% of the flies were knocked down), compared with the standard aerosol. In the direct spray application to houseflies, the KDT50 was reduced by 50%, while in the indirect spray the KDT50 was reduced by 40%. In the indirect spray of mosquitoes, the KDT50 was reduced by 22%. With higher active ingredient concentrations of 2.09 g kg-1 for bioallethrin and 0.39 g kg-1 for bioresmethrin, the charged aerosol also demonstrated faster knockdown than the standard, but the improvement was less marked. In the direct spray application to houseflies, the KDT50 was reduced by 21% compared with the standard aerosol, while in the indirect spray the KDT50 was reduced by 16%. In the indirect spray of mosquitoes, the KDT50 was reduced by 24%. The percentage mortality after 24 h was also increased with the charged aerosol. Charge carried by the droplets results in increased interception of the insecticide, as the droplets are attracted to the insects in flight and space charge effects within the aerosol could cause improved dispersion in the test chamber.

Aerosols↗

PubMed1988

Evaluation of a real-time aerosol monitor (RAM-S) for inhalation studies.

Measurement of the aerosol concentration in inhalation toxicology studies is generally done by gravimetric and/or chemical analysis of filter samples taken over a known period of time at a fixed sampling flow rate. The value obtained represents the time-averaged concentration in an exposure chamber. However, the filter method does not provide information as to the stability of aerosol concentration in "real-time" nor as to the time required for the aerosol concentration to reach the target value during the start-up of exposures. In order to accomplish evaluation of aerosol stability and chamber rise and fall times, a direct measurement device is required. An available real-time aerosol monitor (RAM-S, GCA Corp., Bedford, MA) is a photometer which collects scattered light from an aerosol cloud at a 70 +/- 25 degrees angle. The output signal is 0 to 10 volt with three ranges corresponding to maximum aerosol concentrations of 200, 20, and 2 mg/m3. The performance of the RAM-S was evaluated in inhalation studies involving nickel sulfate hexahydrate, nickel oxide, nickel subsulfide, and azodicarbonamide. Several RAM-S units were calibrated by obtaining both filter samples and voltage readings of a RAM-S simultaneously. Results indicated that the response of the RAM-S instruments was linear. However, the voltage output per given aerosol concentration was different for each compound used. Furthermore, there was interinstrument variability in the voltage response to aerosol concentration of a given compound. At concentrations higher than 100 mg/m3, modification of the flow system in the RAM-S was made to increase the sheath air around the optical system and also to dilute the aerosol concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗