Expired Air Samples Research Articles

Biological monitoring of occupational exposure to low levels of benzene.

To obtain reference values for the biological monitoring of benzene, the kinetics of benzene were studied in volunteers. Benzene in blood and expired air could easily be followed until the next morning after a 4-h exposure to a benzene concentration of 10 cm3.m-3. Even after exposure to 1.7 cm3.m-3 the benzene levels in the morning blood and expired air samples differed from those in unexposed subjects. One hour after exposure to 10 and 1.7 cm3.m-3 the mean levels of benzene were 238 and 25 nmol.l-1 in blood and 13.2 and 2.5 mumol.m-3 in exhaled air, respectively. It was concluded that, at high benzene levels (approximately 10 cm3.m-3), samples collected 16 h after exposure reflect the body burden of benzene, while at low exposure (< 1 cm3.m-3) samples collected 1 h after exposure may be used to estimate the exposure over the preceding few hours. Exposure to benzene from smoking is a potential confounder in estimating occupational exposure to low levels of benzene.

Use of naturally enriched mixed food in 13C breath tests applied in young suckling calves.

Utilization of three milk diets including cream, casein or whey, each naturally labelled with 13C (1 mmol 13C excess) from C4 sources, by six young male calves of the Deutsche Fleckvieh breed was investigated in a Latin-square split-plot design. Each milk diet was examined under resting conditions and during a short period of physical exercise on a treadmill. Delta 13C values (/1000) in carbon dioxide in expired air were measured at intervals of about 1 h during 6.5 h after food intake. Expired air samples for CO2 isolation, subsequent isotopic analysis, measurement of CO2 production and respiratory quotient were taken at about hourly intervals and 13C recovery rates over 6.5 h were calculated. Feeding milk containing enriched milk casein, cream, or whey resulted in maximal significant 13C enrichments over background (delta 13C) in CO2 of +1, +2.4 and +2.2 /1000, and recovery rates of 3.6, 9.9 and 12.2% respectively. This comparison shows the different kinetic behaviour of the main nutrients during the oxidation in tissues. The short exercise period (5 min at 1 J/s per kg body-weight +5 min at 2 J/s per kg body-weight) did not influence the recovery rates significantly. However, after 10 min of muscular exercise there was a brief decrease in delta 13C value of expired air which disappeared within the first 5 min of rest. These experiments demonstrate for the first time the applicability of the 13C breath test with naturally enriched diets in animal nutrition research and that quantitative results may be obtained.

Hemoglobin concentration and working capacity of nonpregnant rural women of the Kathmandu valley of Nepal.

The relationship between hemoglobin concentration, nutritional status, and working capacity of village women in Nepal was investigated. Subjects were 71 nonpregnant women (ages 18 to 60 yr) living at altitudes ranging from 1,300 to 1,600 m in a rural area near Kathmandu. Half of the women (51%) performed manual wage labor on a daily basis, working as field hands during the agricultural season and breaking rocks into gravel during the remainder of the year; the remaining 49% worked only in their own fields or in exchange labor groups. Anemia was mild but widespread; 62% of the women had hemoglobin concentrations of 12.0 gm/dl or lower. Mean hemoglobin for the total sample was 11.7 ± 1.4 gm/dl (range 7.2 to 15.6 gm/dl). A step test was used to measure working capacity, and expired air samples were analyzed for O2 and CO2 using a Scholander 0.5 ml gas analyzer. Caste and ethnic groups differed significantly with respect to hemoglobin concentration (P < 0.005) and heart rate response to submaximal exercise (P < 0.001), but not in anthropometric measurements. Among those ethnic groups accustomed to daily physical labor, i.e., the Newars and Tamangs, lower hemoglobin concentration was correlated significantly with higher heart rate, higher oxygen uptake, and lower mechanical efficiency during submaximal aerobic exercise.

Comparison of Smoking Prevalence in School Students Sampled from the United States of America and the Union of Soviet Socialist Republics

To assess the smoking prevalence among adolescents in the USA and the USSR, students in Moscow and Minneapolis were surveyed by common protocol and identically trained staff. Smoking habits were measured by a self-report questionnaire and an expired air sample of carbon monoxide (CO). Significant gender differences were found between the two national groups. Among girls in the USA, there was a significantly higher rate of weekly smoking as compared to girls in the USSR. Among boys in the USSR as compared to those in the USA, there was a significantly higher rate of ever smokers and daily smokers, but also of ex-smokers. These gender differences may reflect cultural differences in smoking patterns between the two countries. Cigarette smoking is clearly a public health problem in both countries with its onset in adolescence.

Human inhalation pharmacokinetics of 1,1,2-trichloro-1,2,2-trifluoroethane (FC113)

Seven male volunteers were exposed to atmospheric concentrations of either 1980, 4100 or 7630 mg m-3 1,1,2-trichloro-1,2,2-trifluoroethane (FC113) for 4 h. Blood and expired air samples were collected during the exposure period and for several days subsequently and analysed for FC113. Blood and breath concentrations of FC113 were related to the administered dose with some variation between individuals. The low blood/breath ratios measured are consistent with the low solubility of FC113 in blood. The absorption and elimination of FC113 can be described by a three-compartment model and the average half-lives of elimination of FC113 in breath were 0.22, 2.3 and 29 h. A pulmonary retention during the exposure period of 14% was measured but only 2.6 to 4.3% of the dose was recovered unchanged in breath after the exposure period, suggesting that FC113 could be metabolised following inhalation exposure. It is concluded that a practical method for biological monitoring during occupational exposure would be to measure end-tidal breath concentrations of FC113 in samples taken the morning after exposure. The predictive value of such a measurement can be improved if the results are normalised to the body fat content of individual workers which can be estimated from height and weight measurements.

A computerized classification technique for screening for the presence of breath biomarkers in lung cancer.

A simple computer-based screening technique has been developed for classifying human expired air components into 16 chemical classes, based on empirical formulas. The sort procedure was developed to simplify the screening of the composition of expired air samples by sorting all components into chemical classes and classifying components at the greater than 75% and greater than 90% occurrence levels. Both occurrence-rate components are then evaluated as diagnostic markers in a discriminant function model for their ability to detect lung cancer. Of the 386 components detected in the gas chromatography/mass spectrometry (GC/MS) data files, 45 components were present at the greater than 75% occurrence level and 28 components at the greater than 90% occurrence level. Thus, this preliminary sort routine, performed by using a simple macro program installed into a standard personal-computer spread-sheet, greatly reduces the amount of data required for statistical treatment. Such a sort routine can also be applied as easily to other complex GC/MS data files for the purpose of data reduction.

Energy Requirements of Squash and Racquetball

In brief: To quantify and compare the aerobic energy costs of recreational squash and racquetball, oxygen consumption (VO2) was determined with the direct method in 32 male subjects. Expired air samples were collected on three occasions during play, in each of two games against different opponents. Heart rates were monitored throughout each game. The energy expenditure in racquetball was only slightly less than for squash (600 kcal·hr−1 or 2,520 kJ·hr−1 for racquetball, 661 kcal·hr−1, 2,820 kJ·hr−1 for squash). The overall intensity of play was 57% and 51% of VO2 max for the squash and racquetball players, respectively. Thus, the average intensity level and the total energy expenditure in about 30 minutes of play would be appropriate for an exercise session in a program designed for the development and maintenance of fitness in healthy adults.

Identification of isoprenoid-type components in human expired air: a possible shunt pathway in sterol metabolism.

Expired air samples have been analyzed from three groups of human subjects (normal, liver dysfunction, lung cancer) and the baboon (Papio anubus). Of the several hundred compounds present, three compounds were of particular interest due to their structural relationship to the isoprenoid-type intermediates in the sterol pathway. These compounds were 1-methyl-4-(1-methyl-ethenyl)-cyclohexene, 6-methyl-5-hepten-2-one, and 6,10-dimethyl-5,9-undecadien-2-one. Hydroxyacetone was also found in all samples screened. The relationship of these compounds to the non-sterol pathway of mevalonate metabolism is discussed.

Blood and Alveolar Toluene Concentrations in Workers during the Workshift and the Morning After

Abstract Occupational toluene exposures were studied in workers during the workshift and the morning after by testing toluene concentrations in environmental air, alveolar air and blood. During the workshift, the environmental toluene concentration was measured by means of continuous sampling over the 7-hour workshift and by instantaneous sampling at random times during and at the end of the workshift. Alveolar toluene concentration was measured by means of expired-air samples which were collected simultaneously with the instantaneous environmental air samples. Blood toluene concentration was measured in venous blood samples collected at the end of the workshift. The results showed that the blood toluene concentrations correlated better with the environmental toluene concentrations measured continuously during all the time of exposure than with the instantaneous environmental toluene concentrations measured at the end of the workshift. However, the aveolar toluene concentrations correlated better with the instantaneous environmental toluene concentrations measured at the same time than with the environmental toluene concentration measured continuously over the workshift. Brugnone, F.; De Rosa, E.; Perbellini, L; Bartolucci, G. B.; Pasini, F.; Faccini, G. Blood and alveolar toluene concentrations in workers during the workshift and the morning after.

Two‐Hour Lactose Breath Hydrogen Test

SummaryCurrent requirements for the lactose breath hydrogen test (LBHT) include serial expired air samplings and multiple hydrogen (H2) determinations. One hundred thirty‐two consecutive LBHTs were evaluated to determine whether multiple samplings are indeed necessary for detection of lactose malabsorption. Expired air samples were collected at 0, 30, 60, 90, 120, 150, and 180 min following ingestion of lactose. Fifty‐five LBHTs were positive for lactose malabsorption. All tests showed abnormally elevated breath H2 concentrations at 120 min. The mean value of the change in parts per million (Δ ppm) of H2 at 120 min (51.1 ± 4.7 SEM) was higher than at any other time point. If only the 120‐min samples were examined without subtracting the initial concentrations, four of the 77 negative tests (5.2%) would have been falsely positive. Thus, the values of H2 at 0 and 120 min were sufficient to define lactose malabsorption in all cases. We conclude that just as a single blood sample now suffices for determining xylose malabsorption, so expired air sampling at only 0 and 120 min during the LBHT is a reliable method for detecting lactose malabsorption and diminishes the need for acquiring and analyzing multiple samples.

Two-hour lactose breath hydrogen test.

Current requirements for the lactose breath hydrogen test (LBHT) include serial expired air samplings and multiple hydrogen (H2) determinations. One hundred thirty-two consecutive LBHTs were evaluated to determine whether multiple samplings are indeed necessary for detection of lactose malabsorption. Expired air samples were collected at 0, 30, 60, 90, 120, 150, and 180 min following ingestion of lactose. Fifty-five LBHTs were positive for lactose malabsorption. All tests showed abnormally elevated breath H2 concentrations at 120 min. The mean value of the change in parts per million (delta ppm) of H2 at 120 min (51.1 +/- 4.7 SEM) was higher than at any other time point. If only the 120-min samples were examined without subtracting the initial concentrations, four of the 77 negative tests (5.2%) would have been falsely positive. Thus, the values of H2 at 0 and 120 min were sufficient to define lactose malabsorption in all cases. We conclude that just as a single blood sample now suffices for determining xylose malabsorption, so expired air sampling at only 0 and 120 min during the LBHT is a reliable method for detecting lactose malabsorption and diminishes the need for acquiring and analyzing multiple samples.

Lactose Malabsorption Is Not a Cause of Diarrhea During Phototherapy

Lactose malabsorption is not a cause of diarrhea during phototherapy. Jaundiced neonates under phototherapy develop diarrhea or loose stools during the treatment. These phenomena were attributed to an induced lactase deficiency caused by bilirubin breakdown products. We investigated lactose malabsorption in 59 neonates—29 normals and 30 jaundiced under phototherapy. Five‐hour hydrogen breath tests were performed. Preprandial and postprandial (at 30, 60, 120, 180, 240, and 300 min) expired air samples were analyzed for hydrogen. Ten controls and five jaundiced neonates had positive hydrogen breath tests. Eighteen controls and 16 neonates under phototherapy had preprandial hydrogen (concentrations above 5 ppm). In our hands, lactase deficiency and lactose malabsorption were not induced by phototherapy. Lactase deficiency is therefore not the cause of diarrhea associated with phototherapy.

Lactose malabsorption is not a cause of diarrhea during phototherapy.

Lactose malabsorption is not a cause of diarrhea during phototherapy. Jaundiced neonates under phototherapy develop diarrhea or loose stools during the treatment. These phenomena were attributed to an induced lactase deficiency caused by bilirubin breakdown products. We investigated lactose malabsorption in 59 neonates--29 normals and 30 jaundiced under phototherapy. Five-hour hydrogen breath tests were performed. Preprandial and postprandial (at 30, 60, 120, 180, 240, and 300 min) expired air samples were analyzed for hydrogen. Ten controls and five jaundiced neonates had positive hydrogen breath tests. Eighteen controls and 16 neonates under phototherapy had preprandial hydrogen (concentrations above 5 ppm). In our hands, lactase deficiency and lactose malabsorption were not induced by phototherapy. Lactase deficiency is therefore not the cause of diarrhea associated with phototherapy.

The Effect of Dental Amalgams on Mercury Levels in Expired Air

The expired air of a group of 48 persons, 40 with and eight without dental amalgam restorations, was analyzed for its mercury content before and after chewing. Expired air samples were collected in polyethylene bags, and a known quantity of each was pumped into the mercury detector for measurement. The results showed that examined subjects with dental amalgams had higher pre-chewing mercury levels in their expired air than those without amalgams. After chewing, these levels were increased an average of 15.6-fold in the former and remained unchanged in the latter group. It was concluded that in situ dental amalgams can increase the level of mercury in expired air.

Progressive changes in energy cost during a three-hour race-walk exercise.

Twenty experienced race-walkers were exercised in a controlled routine walking at 11.6 km/hr continuously for 3 hr, alternately on a treadmill and a cinder track. Analyses of expired air samples taken at 30 min intervals were used to calculate average R.Q. and energy expenditure. R.Q. was found to decrease progressively from 0.92 to 0.66 in the 3 hr and remained at this level 30 min later. The mean energy cost rose from 46.2 to 55.4 kJ/min or 24.7 to 29.7 kJ/min.m2. The results indicate that this group probably experienced an elevation of aerobic activity as they utilized progressively more fat to satisfy metabolic demands and that R.Q. may be a good indicator for determining recovery after severe long duration exercise.

The effect of air temperature on physical working capacity.

Measurements were taken in ten healthy young male subjects, ages 20 to 25, under air temperature conditions of 5, 20, 35, and 50 degrees C. The relative humidity was maintained at 50% throughout all the air temperature conditions. Maximum work loads were obtained by treadmills. The first work load was 95 m/min 0 degrees grade; this was increased by 1 degree every one minute until the subjects reached a self-imposed maximum. The heart rate and expired air sample during the last 30 sec work was used for statistical analyses. The analysis of variance confirmed a significance effect of air temperature factor in the cases of the endurance time until the exhaustion, maximal oxygen uptake, maximal carbon dioxide production, heart rate, respiratory exchange ratio, and oxygen pulse. The regression analyses disclosed the following relationships between maximal oxygen uptake (VO2 max) or heart rate (HR) and air temperature: VO2 max = 2472 + 29.5Ta-0.6Ta2(ml. STPD), HR = 173 + 2.0Ta-0.09Ta2 + 0.001Ta3, where Ta shows air temperature in centigrade. The physiological mechanism underlying the changes in maximal oxygen uptake in heat is discussed.

Characterization of human expired air: a promising investigative and diagnostic technique.

Expired air samples have been collected from a carefully selected population of normal healthy human subjects under controlled experimental conditions. The samples were concentrated and analyzed by quantitative, reproducible and sensitive techniques which resulted in well-defined composite compositional and occurrence profiles of the organic constituents present in normal expired air. The composite profiles provide valuable baseline information upon which suitable correlation studies may be advanced toward the use of human expired air for diagnostic purposes.

Nicotine poisoning and rapid smoking.

In an earlier article (Horan, Hackett, Nicholas, Linberg, Stone, & Lukaski, 1977), we reported a number of physiological changes that occur in subjects undergoing rapidsmoking treatment for cigarette addiction. Briefly, heart rates increased 35 beats per minute and blood pressures rose 15/10 mm Hg. Carboxyhemoglobin levels were estimated at l/o-\Q% based on expired-air samples. Finally, cardiac arrhythmias occurred during rapid smoking with two of the six smokers and also with one ex-smoking pilot subject. Our data added fuel to a controversy concerning the safety of the rapid-smoking technique (cf. Dawley & Dillenkoffer, 1975; Hauser, 1974; Lichtenstein, 1974; Hynd, Severson, & O'Neal, Note 1). At that time we reserved judgment on the hazard potential of the rapid-smoking treatment pending a controlled investigation that would isolate the possible effects of subject age, normal smoking, and rapid breathing, as well as carbon monoxide, nicotine, and other combustible product levels. Our recent perusal of the literature on the toxic effects of nicotine, however, has produced a startling deja vu experience. Apart from slight tachycardia, low levels of nicotine (circa 2 mg) produce no serious electrocardiographic changes in normal or cardiac patients (Voile & Koelle, 196S; von Ahn, 1960). Higher doses, on the other hand, can be lethal. Some of the symptoms of acute nicotine poisoning that precede

Nicotine poisoning and rapid smoking.

In an earlier article (Horan, Hackett, Nicholas, Linberg, Stone, & Lukaski, 1977), we reported a number of physiological changes that occur in subjects undergoing rapidsmoking treatment for cigarette addiction. Briefly, heart rates increased 35 beats per minute and blood pressures rose 15/10 mm Hg. Carboxyhemoglobin levels were estimated at l"/o-\Q% based on expired-air samples. Finally, cardiac arrhythmias occurred during rapid smoking with two of the six smokers and also with one ex-smoking pilot subject. Our data added fuel to a controversy concerning the safety of the rapid-smoking technique (cf. Dawley & Dillenkoffer, 1975; Hauser, 1974; Lichtenstein, 1974; Hynd, Severson, & O'Neal, Note 1). At that time we reserved judgment on the hazard potential of the rapid-smoking treatment pending a controlled investigation that would isolate the possible effects of subject age, normal smoking, and rapid breathing, as well as carbon monoxide, nicotine, and other combustible product levels. Our recent perusal of the literature on the toxic effects of nicotine, however, has produced a startling deja vu experience. Apart from slight tachycardia, low levels of nicotine (circa 2 mg) produce no serious electrocardiographic changes in normal or cardiac patients (Voile & Koelle, 196S; von Ahn, 1960). Higher doses, on the other hand, can be lethal. Some of the symptoms of acute nicotine poisoning that precede

A vacuum chamber for simplifying the collection of expired air samples.

Metalized bags for collection and storage of expired air for the study of oxygen consumption in man have been described by Johnsonet al. [J. appl. Physiol.22, 377–379 (1967)]. We have developed a vacuum chamber to permit rapid, multiple sampling with these metalized bags. The reproducibility and reliability of oxygen and carbon dioxide measurements of samples collected with the vacuum chamber compare favorably with accepted standard techniques, such as that of Campney and Pleasants [Res. Quart. Amer. Ass. Hlth phys. Educ.36, 207–210 (1965)].