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- Bake, Björn, 1939, et al.
(författare)
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Exhaled particles and small airways
- 2019
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Ingår i: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-993X. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundOriginally, studies on exhaled droplets explored properties of airborne transmission of infectious diseases. More recently, the interest focuses on properties of exhaled droplets as biomarkers, enabled by the development of technical equipment and methods for chemical analysis. Because exhaled droplets contain nonvolatile substances, particles is the physical designation. This review aims to outline the development in the area of exhaled particles, particularly regarding biomarkers and the connection with small airways, i e airways with an internal diameter<2mm.Main bodyGeneration mechanisms, sites of origin, number concentrations of exhaled particles and the content of nonvolatile substances are studied. Exhaled particles range in diameter from 0.01 and 1000m depending on generation mechanism and site of origin. Airway reopening is one scientifically substantiated particle generation mechanism. During deep expirations, small airways close and the reopening process produces minute particles. When exhaled, these particles have a diameter of <4m. A size discriminating sampling of particles <4m and determination of the size distribution, allows exhaled particle mass to be estimated. The median mass is represented by particles in the size range of 0.7 to 1.0m. Half an hour of repeated deep expirations result in samples in the order of nanogram to microgram. The source of these samples is the respiratory tract ling fluid of small airways and consists of lipids and proteins, similarly to surfactant. Early clinical studies of e g chronic obstructive pulmonary disease and asthma, reported altered particle formation and particle composition.ConclusionThe physical properties and content of exhaled particles generated by the airway reopening mechanism offers an exciting noninvasive way to obtain samples from the respiratory tract lining fluid of small airways. The biomarker potential is only at the beginning to be explored.
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| 2. |
- Forsell, Karl, et al.
(författare)
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Benzene Exposure and Biomarkers in Alveolar Air and Urine Among Deck Crews on Tankers Transporting Gasoline
- 2019
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Ingår i: Annals of work exposures and health. - : Oxford University Press. - 2398-7316 .- 2398-7308. ; 63:8, s. 890-897
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Increased rates of leukaemia have been found among tanker crews. Occupational exposures to the leukomogen benzene during loading, unloading, and tank cleaning are possible causes. Studies on older types of tankers carrying gasoline with most handling being done manually have revealed important exposures to benzene. Our study explores benzene exposures on tankers with both automatic and manual systems. Correlations between benzene exposure and benzene in alveolar air (AlvBe), benzene in urine (UBe), and trans,trans-muconic acid (ttMA) in urine were investigated.METHODS: Forty-three male seafarers (22 deck crewmembers and 21 not on deck) on five Swedish different product and chemical tankers transporting 95- or 98-octane gasoline were investigated between 1995 and 1998. The tankers used closed systems for the loading and unloading of gasoline but stripping and tank cleaning were done manually. Benzene in respiratory air was measured using personal passive dosimeters during a 4-h work shift. Samples for biomarker analyses were collected pre- and post-shift. Smoking did occur and crewmembers did not use any respiratory protection during work.RESULTS: The average 4-h benzene exposure level for exposed was 0.45 mg m-3 and for non-exposed 0.02 mg m-3. Benzene exposure varied with type of work (range 0.02-143 mg m-3). AlvBe, UBe, and ttMA were significantly higher in post-shift samples among exposed and correlated with exposure level (r = 0.89, 0.74, and 0.57, respectively). Smoking did not change the level of significance among exposed.DISCUSSION: Benzene in alveolar air, unmetabolized benzene, and ttMA in urine are potential biomarkers for occupational benzene exposure. Biomarkers were detectable in non-exposed, suggesting benzene exposure even for other work categories on board tankers. Work on tankers carrying gasoline with more or less closed handling of the cargo may still lead to significant benzene exposure for deck crewmembers, and even exceed the Swedish Occupational Exposure Limit (OEL; 8-h time-weighted average [TWA]) of 1.5 mg m-3.
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| 5. |
- Hagberg, Stig, et al.
(författare)
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Exposure to volatile methacrylates in dental personnel.
- 2005
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Ingår i: Journal of occupational and environmental hygiene. - : Informa UK Limited. - 1545-9624 .- 1545-9632. ; 2:6, s. 302-6
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Tidskriftsartikel (refereegranskat)abstract
- Dental personnel are exposed to acrylates due to the acrylic resin-based composites and bonding agents used in fillings. It is well known that these compounds can cause contact allergy in dental personnel. However, in the 1990s, reports emerged on asthma also caused by methacrylates. The main volatile acrylates in dentistry are 2-hydroxyethyl methacrylate and methyl methacrylate. The aim of this study was to quantify the exposure to these acrylates in Swedish dental personnel. We studied the exposure to 2-hydroxyethyl methacrylate and methyl methacrylate in five randomly selected public dental clinics and at the Faculty of Odontology at G?teborg University. In total, 21 whole-day and 46 task-specific short-term (1-18 min) measurements were performed. The median 8-hour time-weighted averages were 2.5 microg/m3 (dentists) and 2.9 microg/m3 (dental nurses) for 2-hydroxyethyl methacrylate, and 0.8 microg/m3 (dentists) and 0.3 microg/m3 (dental nurses) for methyl methacrylate. The maximum short-term exposure levels were 79 microg/m3 for 2-hydroxyethyl methacrylate and 15 microg/m3 for methyl methacrylate, similar in dentists and dental nurses. The observed levels are much lower than in complete denture fabrication. We found only one previous study in dentistry and it showed similar results (though it reported short-term measurements only). Irritant effects would not be expected in healthy people at these levels. Nevertheless, occupational respiratory diseases due to methacrylates may occur in dental personnel, and improvements in the handling of these chemicals in dentistry are warranted. This includes better vials for the bonding agents and avoiding evaporation from discarded materials.
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| 7. |
- Ljungkvist, Göran, 1949
(författare)
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Determination of benzene in urine and breath for monitoring of benzene exposure
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work was to develop and validate methods for determination of unmetabolized benzene in breath and urine. The methods were intended for the bio monitoring of benzene to assess both occupational and environmental exposure.A method was developed for the determination of benzene in end-exhaled air. The sampling device consisted of a modified peak expiratory flow meter into which the subjects expired. A 100 ml sample was drawn through an adsorbent tube, filled with Tenax TA. The adsorbent was thermally desorbed and the analysis was made by gas chromatography (GC) and flame ionization detection (FID). The limit of detection (LOD), with a sample volume of 100 ml, was 0.5 µg/m3. The repeatability varied from 2.6% in the laboratory to 13% in the field. Storage of samples at room temperature for 1 week showed no significant decrease.Two methods for the determination of benzene in urine were developed, both based on sample preparation by dynamic headspace and preconcentration of the analyte on a solid adsorbent. The adsorbent was subsequently thermally desorbed. To achieve sufficient selectivity, we used GC and mass selective (MS) detection in one method and multi-dimensional separation and FID in the other. The selectivity was good in both methods and the performance was comparable. LOD for the MS-method was 6.5 ng/L, and for the multi-dimensional method 7.0 ng/L. Linearity was good in the concentration range examined (20-4000 ng/L). Repeatability was <9%. Recovery in the sample preparation step was 83-85%. Losses during the collection were also studied. Samples could be stored frozen in glass bottles for 1 year.A robust sample preparation method for the extraction of benzene in urine was developed. It was based on extraction through a flat, porous membrane to a gaseous acceptor and pre-concentration on a solid adsorbent. The analysis was made by thermal desorption and GC-MS. The extraction efficiency was close to quantitative (95%) at room temperature. Extraction at 50ºC did not increase recovery. Memory effects were small. Linearity was good in the concentration range examined (20-4000 ng/L). The repeatability at 50 ng/L and 400 ng/L was 1.5% and 1.2%, respectively. The LOD was 12 ng/L. In contrast to dynamic headspace, the method is easily automated.Unmetabolised benzene in breath or urine is a specific biological marker for benzene exposure. The collection of breath and urine is simple, non-invasive and acceptable for the subjects. The limit of detection of the methods permit quantifications of benzene in breath and urine in occupationally exposed subjects, and in the majority of the general population.
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| 8. |
- Ljungkvist, Göran, 1949, et al.
(författare)
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Exploring a new method for the assessment of metal exposure by analysis of exhaled breath of welders
- 2022
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 95:6, s. 1255-1265
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Air monitoring has been the accepted exposure assessment of toxic metals from, e.g., welding, but a method characterizing the actual dose delivered to the lungs would be preferable. Sampling of particles in exhaled breath can be used for the biomonitoring of both endogenous biomarkers and markers of exposure. We have explored a new method for the sampling of metals in exhaled breath from the small airways in a study on welders. Methods Our method for particle sampling, Particles in Exhaled Air (PExA (R)), is based on particle counting and inertial impaction. We applied it on 19 stainless steel welders before and after a workday. In parallel, air monitoring of chromium, manganese and nickel was performed as well as blood sampling after work. Results Despite substantial exposure to welding fumes, we were unable to show any significant change in the metal content of exhaled particles after, compared with before, exposure. However, the significance might be obscured by a substantial analytical background noise, due to metal background in the sampling media and possible contamination during sampling, as an increase in the median metal contents were indicated. Conclusions If efforts to reduce background and contamination are successful, the PExA (R) method could be an important tool in the investigations of metals in exhaled breath, as the method collects particles from the small airways in contrast to other methods. In this paper, we discuss the discrepancy between our findings and results from studies, using the exhaled breath condensate (EBC) methodology.
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| 10. |
- Ljungkvist, Göran, 1949, et al.
(författare)
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Two techniques to sample non-volatiles in breath-exemplified by methadone.
- 2018
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Ingår i: Journal of breath research. - : IOP Publishing. - 1752-7163. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The particles in exhaled breath provide a promising matrix for the monitoring of pathological processes in the airways, and also allow exposure to exogenous compounds to be to assessed. The collection is easy to perform and is non-invasive. The aim of the present study is to assess if an exogenous compound-methadone-is distributed in the lining fluid of small airways, and to compare two methods for collecting methadone in particles in exhaled breath. Exhaled particles were collected from 13 subjects receiving methadone maintenance treatment. Two different sampling methods were applied: one based on electret filtration, potentially collecting exhaled particles of all sizes, and one based on impaction, collecting particles in the size range of 0.5-7 μm, known to reflect the respiratory tract lining fluid from the small airways. The collected samples were analyzed by liquid chromatography mass spectrometry, and the impact of different breathing patterns was also investigated. The potential contribution from the oral cavity was investigated by rinsing the mouth with a codeine solution, followed by codeine analysis of the collected exhaled particles by both sampling methods. The results showed that methadone was present in all samples using both methods, but when using the method based on impaction, the concentration of methadone in exhaled breath was less than 1% of the concentration collected by the method based on filtration. Optimizing the breathing pattern to retrieve particles from small airways did not increase the amount of exhaled methadone collected by the filtration method. The contamination from codeine present in the oral cavity was only detected in samples collected by the impaction method. We conclude that methadone is distributed in the respiratory tract lining fluid of small airways. The samples collected by the filtration method most likely contained a contribution from the upper airways/oral fluid in contrast to the impaction method.
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