Application of a new method for analysis of exhaled gas in critically ill patients

Objective: Application of a new method for analysis of exhaled gas in critically ill patients. Design: Open study. Setting: Surgical intensive care unit of an university hospital. Patients: Thirty-seven consecutive, critically ill, mechanically ventilated patients. Interventions: None. Measurements and results: Chemical analysis of the patient's exhaled gas was based upon substance adsorption and concentration onto activated charcoal, microwave desorption and gas chromatographic separation. Patients with acute respiratory distress syndrome (ARDS) exhaled less isoprene than those without ARDS [9.8 (8.2–21.6) vs 21.8 (13.9–41.4) nmol/m² per min [median (95 % confidence interval)], p = 0.04]. In patients who developed pulmonary infection, pentane elimination increased from 0.4 (0.0–5.4) to 2.7 (0.6–6.1, p = 0.05) nmol/m² per min and isoprene elimination decreased from 5.2 (0–33) to 5.0 (0–17, p = 0.05) nmol/m² per min, resulting in a significant increase in pentane/isoprene ratio from 0.1 (0–0.3) to 0.4 (0–15, p = 0.007) when compared to patients without pulmonary infection. Conclusions: The new method allows quantitative analysis of human gas samples with low substance concentrations and is well suited for clinical studies which involve the investigation of metabolic processes in the lung and the body. Received: 17 June 1997 Accepted: 28 November 1997     

The influence of cognitive bias on the perceived odor, irritation and health symptoms from chemical exposure

 Objective: Responses to volatile chemicals are often subjective and variable, both over time and across individuals. Although variability can derive from differences in individual olfactory sensitivity, the response to a chemical stimulus is also influenced by the complex environment surrounding the exposure, which can include the perceiver’s cognitive state. To explore the role of cognitive bias in chemical exposures, we evaluated whether information about the consequences of exposure to acetone could influence ratings of odor and irritation during exposure and/or the frequency or intensity of reported health symptoms following exposure. Methods: Ninety adults (mean age 33.7, range 25–64) with no history of occupational exposure to solvents, were exposed to 800 ppm acetone in a chamber for 20 min. To control for non-specific responses to the odor of acetone, the subjects were also exposed for 20 min to 200 ppm phenylethyl alcohol (PEA), a nonirritant volatile chemical that produces a distinct odor but does not elicit irritation in the vapor phase. Subjects were assigned to one of three groups (n=30/group); each group was given either a positive, negative or neutral bias towards the consequences of exposure to the chemicals in the study. During exposure, subjects rated the intensity of odor and irritation; following exposure, they completed symptom questionnaires. Results: During the 20-min exposure to acetone, the positive bias group exhibited the most adaptation to its odor and the lowest perceived irritation; following exposure they reported the fewest health symptoms. In contrast, the negative bias group rated higher levels of odor intensity and, on average, reported the most overall irritation; following exposure they reported significantly more health symptoms than the other groups. None of the demographic variables studied (e.g., age, gender, race, smoking status) were predictive of the response to odor or irritation. The perceived irritancy of acetone was well predicted by a linear combination of the perceived odor of acetone and the perceived irritation from PEA (the nonirritant), r ²=0.73. Conclusions: The results provide strong evidence that both the perceived odor and cognitive expectations about a chemical can significantly affect how individuals respond to it. Moreover, because naive control subjects appear to exhibit extreme variation in their cognitive evaluations of chemical effects, there may be limited value in using non-exposed controls to assess the irritancy of chemicals for worker populations. Received: 7 May 1996/Accepted: 20 September 1996     

分光光度法测定车间空气中丙酮氰醇

本文建立了用分光光度法测定车间空气中丙酮氰醇的方法。主要是经硅胶管采集空气中的丙酮氰醇,利用其在碱性溶液中分解为丙酮和氰化物的性质,以异菸酸钠—巴比妥酸钠比色法,于600nm比色定量。实验表明,本法检测限为0.3μm/5ml,在0—7μg范围内有良好的线性关系;相对标准偏差为0.9％～3.4％;采样效率97.2％～99.9％;加入0.5、1、2倍(最高容许浓度时在规定采样体积下采集的)丙酮氰醇,其洗脱效率分别为95.3％、91.9％、90.4％。     

Biological monitoring of styrene exposure and possible interference of acetone co-exposure

 The object of this study is the evaluation of some of the toxicokinetic effects of exposure to low concentrations of styrene, and the possible influence of simultaneous exposure to acetone. To this end we studied 19 workmen simultaneously exposed to both solvents. During a week of 4-h work shifts, the workmen underwent daily personal environmental monitoring and the collection of urine samples, at both the beginning and the end of the work period, for the determination of mandelic acid (MA) and phenylglyoxylic acid (PGA). The presence of the solvents in the atmosphere was evaluated using passive personal monitoring and gas chromatography. Average exposure to styrene and acetone were respectively 72.2 mg/m³ and 225.7 mg/m³. MA and PGA were quantified by high-performance liquid chromatography (HPLC). The daily urinary concentration averages, both at commencement and at the end of work shifts, of both the metabolites studied and of the sum of the two, were in statistically significant linear correlation with the average daily styrene exposure. Concentrations of MA and PGA in urine samples collected at the start of the work shift averaged 61.5 mg/g creatinine and 45.2 mg/g creatinine respectively, representing 41% and 72% of those at the end of the work shift which were 148.3 and 62.6 mg/g creatinine, respectively. With equal exposure to styrene, the average urinary concentrations of MA and PGA at both the beginning and end of the work shift increased significantly (P<0.001) during the working week. Moreover, we found that with equal exposure to styrene, urinary excretion of MA, PGA and MA+PGA at the end of the shift was inversely correlated with the intensity of acetone exposure (r=0.4659, 0.3410 and 0.4542 respectively, P<0.001). In conclusion, these results express slower urinary kinetics of styrene metabolites than is usually described in the literature, and favor a tendency to accumulate MA and PGA in the organism as a consequence of the retardation of urinary excretion kinetics. Acetone apparently represents one of the determining factors in this interference. Received: 3 July 1996/Accepted: 20 September 1996     

Solvent exposure in a shoe upper factory

Summary Acetone and n-Hexane concentrations were determined in the environmental air of a shoe upper factory and in the alveolar air and venous blood of the workers employed. The ratio between alveolar and environmental n-hexane concentration (Ca/Ci) was found to be steady during the 4.5 hours of exposure studied, and independent of alveolar ventilation and n-hexane environmental concentration. Lung uptake per minute was correlated with environmental concentration.In the case of acetone the Ca/Ci ratio was found to increase with exposure time, but to be independent of alveolar ventilation and environmental acetone concentration. A correlation was still found between lung uptake and environmental acetone concentration.The correlation found between Ca and Ci suggests the hypothesis that occupational exposure can be studied by testing the alveolar air concentration of individual exposed workers in the case of hexane. Since in the case of acetone the Ca/Ci ratio increases with exposure time, it is necessary to know the time of exposure in order to estimate environmental exposure from alveolar acetone concentration. Blood concentration was correlated with environmental and alveolar concentration in the case of hexane, correlated with alveolar concentration in the case of acetone.     

Comparative embryotoxicity and proteotoxicity of three carrier solvents to zebrafish (Danio rerio) embryos

The present study examines the effects of ethanol (ETOH), dimethyl sulfoxide (DMSO), and acetone on zebrafish embryos and the implications of the observed results on the use of these solvents to zebrafish early life stage tests. The embryos were exposed to different concentrations (0.0, 0.0001, 0.001, 0.01, 0.1, 0.05, 1, 1.5, and 2.0% v/v) of the respective solvents by diluting reagent-grade solvent with reconstituted water [DIN 38415-6-Suborganismische Testverfahren (Gruppe T) Teil 6: Giftigkeit gegenüber Fischen. Deutsches Institute für Normung e.V]. The following endpoints were investigated (mortality, hatching rate, abnormalities, heart rate, and hsp 70 induction). No effect on survival was recorded for both acetone and DMSO even up to the highest concentration. On the other hand, embryos exposed to 1.5% and 2.0% ethanol showed a significant reduction in survival rate. No developmental defects occurred with any of the solvents at the 0.1% concentration. However, starting with 1.0%, weak to very pronounced abnormalities (weak pigmentation, edema, crooked bodies, eye defect, tail defect, reduced heartbeat, and abnormal hatching) were observed depending on the solvent type and the concentration used. Ethanol has been shown to be the most embryotoxic solvent while DMSO and acetone have comparably lesser effects. Heat shock protein 70 was induced by all solvents but at different concentration ranges. DMSO has been shown to be the most potent inducer of stress proteins. Based on the study, the chemicals tested here may be used as carrier solvents in the zebrafish embryo assay at levels below 1.5, 1.5, and 1% v/v for acetone, DMSO, and ethanol, respectively. For stress protein analysis of the exposed embryos, however, the solvent levels should be below 0.1%, 0.01%, and 1.5%, respectively. Additional and separate investigations utilizing other biomarkers should be carried out to further validate the suitability of using these solvents in a typical zebrafish embryo assay.     

顶空气相色谱法测定硝唑尼特中的残留溶剂

目的:建立项空气相色谱测定药物硝唑尼特中残留溶剂的方法.方法:采用DM-WAX毛细管色谱柱(30 m×0.25 mm,0.5 μm);柱温采取程序升温;进样口温度为200℃;FID检测器,检测器温度为250℃;顶空进样,平衡温度为80℃,平衡时间为30 min;以N,N-二甲基甲酰胺为溶剂测定硝唑尼特原料药中丙酮、二氯甲烷的残留量.结果:在本文的色谱条件下,各有机溶剂均能得到有效分离,丙酮、二氯甲烷的浓度分别在250～750 μg·ml-1(r=0.9991)、30～90 μg· ml-1(r=0.9991)范围内线性关系良好;平均回收率分别为99.15％、99.18％,RSD分别为2.17％、2.97％(n=9).结论:本方法简便、快速、准确,可有效检测硝唑尼特中的残留溶剂.     

气相色谱法测定3-氯-7-氨基去乙酰氧基头孢烷酸中残留溶剂

目的:建立3-氯-7-氨基去乙酰氧基头孢烷酸(7-ACCA)中丙酮、甲醇、二氯甲烷、乙酸乙酯、异丁醇、吡啶、甲苯残留量的测定方法。方法:采用气相色谱法,载气为氮气,FID检测器,色谱柱为Agilent INNOWAX毛细管柱,柱温为程序升温:起始温度70℃,保持6 min,以10℃/min升温至160℃,保持1 min;进样量1.0μl,分流进样,分流比10∶1,外标法检测7-ACCA中丙酮、甲醇、二氯甲烷、乙酸乙酯、异丁醇、吡啶、甲苯的含量。结果:在本研究建立的色谱条件下,丙酮、甲醇、二氯甲烷、乙酸乙酯、异丁醇、吡啶、甲苯的最低检出质量浓度分别为2.5μg/ml、1.5μg/ml、15μg/ml、2.5μg/ml、2.5μg/ml、2.5μg/ml、11μg/ml。样品中仅检测到丙酮,且其残留量远在药典规定的限量以下。结论:建立的方法能有效控制7-ACCA中丙酮、甲醇、二氯甲烷、乙酸乙酯、异丁醇、吡啶、甲苯的残留量。     

An examination of MCE filter morphology and implications on preparation and analysis of air samples for asbestos

Morphological imperfections of mixed-cellulose ester filters and their possible influence on sample preparation and analysis of asbestos were examined. Filters were identified with large regions of non-porous “dead zones” which could negatively affect fiber deposition and, therefore, fiber recovery and analysis by Transmission Electron Microscopy (TEM). As these imperfections are effectively erased during the preparation of the sample, they may not be readily observed by TEM. Un-collapsed filters as well as those collapsed using dimethylformamide (DMF) and two acetone techniques were examined. In order to minimize negative sampling and analytical bias, it is suggested that MCE samples be collapsed utilizing a 35% DMF solution, etched with a correctly calibrated low-temperature etcher, carbon coated using a rotating and tilted stage, and analyzed with a strong analyst-independent grid square opening randomization scheme.