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PubMed1985

Human exposures to volatile halogenated organic chemicals in indoor and outdoor air.

Volatile halogenated organic chemicals are found in indoor and outdoor air, often at concentrations substantially above those in remote, unpopulated areas. The outdoor ambient concentrations vary considerably among sampling stations throughout the United States, as well as diurnally and daily. The vapor pressures and air-water equilibrium (Henry's Law) constants of these chemicals influence considerably the likely relative human exposures for the air and water routes. Volatilization of chemicals from indoor uses of water can be a substantial source of exposure, as shown for radon-222. Measurements of air concentrations of trichloroethylene (TCE) in showers using TCE contaminated groundwater show increases with time to as high as one-third of occupational threshold limit values. Using a scaled down experimental shower, such volatilization and subsequent decay in air was also demonstrated. Using a simplified indoor air model and assuming complete volatilization from a full range of typical water uses within the home, calculations indicate that the expected air inhalation exposures can be substantially higher than those from ingestion of these chemicals in drinking water. Although the regulation of toxic chemicals in potable water supplies has focused traditionally on direct ingestion, the volatilization and inhalation from other much greater volume indoor uses of water should be considered as well.

Air Pollutants, Occupational↗
PubMed1985

Health implications of environmental exposure to asbestos.

The health impact of environmental pollution resulting from the industrial use of asbestos can be assessed in three ways. First, there are the direct epidemiological surveys. These indicate that domestic exposure has been responsible for cases of mesothelioma and possibly lung cancer and radiological changes in family contacts of asbestos workers. Exposure in the neighborhood of crocidolite mines and factories has also resulted in cases of mesothelioma but no similar evidence exists for chrysotile or amosite. Neither air nor water pollution has been directly incriminated as a cause of either respiratory or digestive malignancies. Second, a few attempts have been made to extrapolate from exposure response findings in industrial cohorts. For several reasons, even for lung cancer, this approach is dubious: the observed gradients have a 100-fold range in slope; the equivalences of dust, fiber and gravimetric measures are largely guesswork; and the carcinogenic potential of mineral fibers, particularly for the pleura, varies enormously with fiber type and/or dimensions. No adequate exposure-response observations have been made for mesothelioma. A third approach makes use of the differing incidence of mesothelioma in men and women. Data from several countries indicate that, until the 1950s (i.e., 30-40 years after significant industrial use of asbestos began), the rates were similar in both sexes. Since then, the incidence in males has risen steeply--in the U.S. and U.K. at about 10% per annum. In females, on the other hand, there has been little or no convincing increase. These data suggest that the "background" level of mesothelioma in both sexes is and has been about 2 per million per annum and that--as at least some mesothelioma cases in females are directly or indirectly attributable to occupational exposure--there is little room left for any contribution from the general environment. It is recommended that mesothelioma surveillance, backed by appropriate epidemiological inquiries, offers an effective method of monitoring the health impact of asbestos air pollution.

Asbestos↗
PubMed1986

Contribution of organic particulates to respiratory cancer.

This paper presents some of the issues that remain to be resolved in order to assess the risk of cancer related to exposure to organic particulates. Most reviews of the effects of organic particulates from the outdoor environment on the risk of lung cancer show that this source seems to play a minor role. However, as fuel use and chemical composition of air pollutants change, the contribution of outdoor pollution as a cause of cancer may also change. Indoor air pollution is a more important source of exposure to organic particulates than is outdoor exposure. Although there is clear evidence that in occupational settings organic particulates cause human cancer, there has been almost no study of exposure to these types of particulates within indoor settings. Previous research has focused on cigarette smoke as the major indoor pollutant, but more specific characterization of contaminants in both the workplace and the home is required. The health effects of the higher levels of some of these contaminants in the workplace should be evaluated and the results extrapolated to populations exposed to lower levels in the home. Extensive research is needed to characterize organic particulate mixtures appropriately and test them for carcinogenicity. Studies on the health risks of nitropolynuclear aromatic hydrocarbons and polychlorinated dibenzodioxins and dibenzofurans are reviewed, but their contribution to the overall burden of respiratory cancer in humans cannot be estimated at this time. Characterization of mixtures, assessment of exposures, and linkage of exposures to health effects are the objectives of the recommendations proposed for further research.

Air Pollutants↗
PubMed1986

Contribution of environmental fibers to respiratory cancer.

This article reviews studies of the carcinogenicity of mineral fibers, notably asbestos, and presents seven major recommendations for further research. Mineral fibers represent the greatest cause--after cigarette smoke--of respiratory cancer due to air pollutants. Past asbestos exposure may currently account for 2000 mesothelioma deaths per year and 4000 to 6000 lung cancer deaths per year. All major commercial types of asbestos (crocidolite, amosite, and chrysotile) can cause each of the major asbestos-related respiratory diseases. Lung cancers in asbestos-exposed individuals probably do not have a different distribution of histological types from that of non-asbestos-related lung cancers. Nonoccupational exposures are likely to be associated with malignant disease outcomes qualitatively similar to those associated with occupational exposures. Further investigations of fibers are needed to characterize the relationships among physicochemical properties, patterns of migration and clearance, dose, and adverse health effects. Transmission electron microscopy has been found to be the preferred method of analysis of environmental fibers. Relations among time factors (e.g., age at first exposure), dose, and risk for adverse health effects require analyses of existing and new epidemiologic studies of exposed cohorts. Concomitant exposure, behavioral factors, and host factors affecting susceptibility to asbestos should be identified.

Air Pollutants↗
PubMed1992

Heat exposure standards and women's work: equitable or debatable?

Although there is an abundant literature on the health effects of occupational heat exposure, very few authors have addressed the question of the effects of heat stress on women workers. Knowledge about the effects of work in hot environments is mainly derived from the study of "heavy" muscular activity and current heat exposure standards are based on an energy criterion according to metabolic load. Metabolic load does not reflect cardiac strain associated with sedentary, repetitive work, involving static effort. The research presented here was conducted in an industrial laundry with 11 women mangle operators exposed to moderate heat stress during the summer months and whose work activity is classified as light on the basis of energy expenditure. Physiological and symptomatological responses, work activity and ambient temperature were assessed over 3 complete work days in summer and in winter. Recorded and perceived temperature, discomfort, feelings of fatigue and symptoms of thermal stress were significantly higher in summer than in winter. Symptoms of drowsiness and musculo-skeletal aches were reported equally in both seasons. Heart rate was high in both seasons, as were calculated indices of cardiac strain. Recommended limits for cardiac strain were surpassed significantly more often in summer than in winter. It is suggested that threshold levels should be redefined to include the prevention of cardiac strain resulting from cumulative effects of heat stress and sedentary, repetitive activity, typical of many women's job with low energy requirement.

Energy Metabolism↗
PubMed2005

Airway narrowing measured by spirometry and impulse oscillometry following room temperature and cold temperature exercise.

STUDY OBJECTIVE: The efficacy of using impulse oscillometry (IOS) as an indirect measure of airflow obstruction compared to spirometry after exercise challenges in the evaluation of exercise-induced bronchoconstriction (EIB) has not been fully appreciated. The objective was to compare airway responses following room temperature and cold temperature exercise challenges, and to compare whether IOS variables relate to spirometry variables. DESIGN: Spirometry and IOS were performed at baseline and for 20 min after challenge at 5-min intervals. SETTING: Two 6-min exercise challenges, inhaling either room temperature (22.0 degrees C) or cold temperature (- 1 degrees C) dry medical-grade bottled air. At least 48 h was observed between these randomly assigned challenges. PARTICIPANTS: Twenty-two physically active individuals (12 women and 10 men) with probable EIB. INTERVENTIONS: Subjects performed 6 min of stationary cycle ergometry while breathing either cold or room temperature medical-grade dry bottled air. Subjects were instructed to exercise at the highest intensity sustainable for the duration of the challenge. Heart rate and kilojoules of work performed were documented to verify exercise intensity. MEASUREMENTS AND RESULTS: Strong correlations were observed within testing modalities for post-room temperature and post-cold temperature exercise spirometry and IOS values. Spirometry revealed no differences in postexercise peak falls in lung function between conditions; however, IOS identified significant differences in respiratory resistance (p < 0.05), with room temperature-inspired air being more potent than cold temperature-inspired air. CONCLUSIONS: Correlations were found between spirometric and IOS measures of change in airway function for both exercise challenges, indicating close equivalency of the methods. The challenges appeared to elicit the EIB response by a similar mechanism of water loss, and cold temperature did not have an additive effect. IOS detected a difference in degree of response between the temperatures, whereas spirometry indicated no difference, suggesting that IOS is a more sensitive measure of change in airway function.

Adult↗
PubMed1997

Intra-cage air change rate on forced-air-ventilated micro-isolation system--environment within cages: carbon dioxide and oxygen concentration.

Recently, a forced-air-ventilated micro-isolation system (FVMIS) has been recognized to accurately maintain microenvironmental conditions inside cages, but the details of the relationship between the concentrations of carbon dioxide (CO2) and oxygen (O2) and the air change rate inside the cages have never been reported. In this study, the proper intra-cage air change rate was examined based on the CO2 concentration and O2 concentration inside the cages measured by changing the ventilation volume inside the closed cages of the FVMIS while housing animals. In the experiments, three 8-week-old Wistar strain male rats weighing 303 g on average were housed in each FVMIS cage (capacity: 0.0223 m3), and the temperature, relative humidity, CO2 concentration and O2 concentration were measured when the air change rate inside the cages was varied from 10 air changes per hour (ACH) to 120 ACH. It proved that the CO2 concentration in the FVMIS cages decreased uniformly with the increase in the air change rate. As a result, 60 ACH was required to maintain the CO2 concentration level inside the FVMIS cages equivalent to or less than that in the conventional housing. Otherwise, when based on the O2 concentration, 50 ACH was required. In consideration of these results and others based on ventilation, airflow, temperature and the ammonia concentration reported previously, we concluded that the proper air change rate inside the FVMIS cages should be approximately 60 ACH.

Air↗
PubMed2000

Development and survival of immature Aedes albopictus and Aedes triseriatus (Diptera: Culicidae) in the laboratory: effects of density, food, and competition on response to temperature.

Effects of food, density, and heterospecific interactions on temperature-dependent development of Aedes albopictus (Skuse) and Aedes triseriatus (Say) larvae and pupae were described using a degree-day model. Under all conditions, the predicted number of degree-days (DD(T0)) to complete larval development was less, and the threshold temperature (T0) for initiation of larval development was higher for Ae. albopictus than for Ae. triseriatus. The DD(T0) for both species was food and density dependent. However, the per capita food ration appeared to exert a greater influence on the developmental times of Ae. triseriatus immatures, whereas for Ae. albopictus effects of density were not completely eliminated by an increase in the per capita food ration. The presence of heterospecific larvae did not prolong the DD(T0) of either species. At the low food ration, DD(T0) for both species were significantly greater under conspecific conditions. The DD(T0) for Ae. triseriatus increased directly as the proportion of conspecific larvae increased. However, when a higher per capita food ration was provided, conspecific effects on DD(T0) were mitigated. For Ae. albopictus, estimated DD(T0) values for larvae reared in pure culture were significantly higher than when heterospecific larvae were present, regardless of the per capita amount of food provided. Survivorship of immatures was density and food-dependent for both species. Ae. albopictus exhibited higher immature survivorship under all conditions relative to Ae. triseriatus. For both species, survival probabilities were lowest under conditions of high density and low food. Addition of food improved survival for both species. The presence of heterospecific larvae exerted a differential effect on the survivorship response of Ae. albopictus immatures to temperature. Lowest probability of survival for Ae. albopictus was occurred at low temperature when the proportion of heterospecific larvae in containers was the highest. In contrast, at high temperatures, survivorship of immatures improved, but was lowest for pure species cultures. For Ae. triseriatus, survivorship of immatures was consistently lower for pure species cultures regardless of the temperature. Standing crop production of adults of both species was primarily food rather that density-dependent. Under field conditions, Ae. triseriatus were predicted to initiate development sooner and exhibit faster population growth early in the season than Ae. albopictus. However, because of the shorter DD(T0), Ae. albopictus population growth was predicted to surpass that of Ae. triseriatus populations later in the season. Based on optimal DD(T0) values from laboratory experiments, spring emergence dates of Ae. triseriatus females in western North Carolina for 1989 and 1990 were predicted from accumulated degree-days calculated from local air temperature records. Predicted emergence dates were congruent with results of a previous survey for the same locality, indicating that accumulated degree-days can be used to accurately predict the seasonal occurrence of Ae. triseriatus. The utility of the degree-day approach in predicting the phenology of Ae. albopictus remains to be established.

Aedes↗
PubMed1988

Increased subjective symptom prevalence among workers exposed to trichloroethylene at sub-OEL levels.

Over 100 workers exposed to trichloroethylene (TRI) mostly at less than 50 ppm during the production or vapor degreasing operation and about an equal number of the non-exposed control workers were examined for subjective symptoms, hematology, serum biochemistry, and sugar, protein and occult blood in urine. Essentially all the clinico-laboratory tests stayed normal, and there was no significant differences in the findings between the exposed and the controls. Thus, no clinically significant effects of TRI exposure were found in the blood and liver functions among the exposed workers as compared with the controls. The prevalence of the subjective symptoms was, however, significantly higher in the exposed group than in the controls, and dose-response relationship could be established in some selected symptoms such as nausea, heavy feeling in the head, forgetfulness, tremor in extremities, cramp in extremities and dry mouth, although the exposure was low. The findings warrant further attention to the effects of TRI especially on the central nervous system at the concentration lower than e.g., 50 ppm.

Adult↗
PubMed1998

A survey of bedroom and bed climate of the elderly in a nursing home.

Bedroom and bed climate of the elderly in a nursing home were surveyed. Twenty-two elderly subjects were divided into four groups depending on their Activity of Daily Living (ADL) and gender. The four groups were: male and female subjects with almost no problems in daily life and an ADL score higher than 5 [H males, H females] and male and female subjects who normally stayed in bed all day with an ADL score lower than 2 [L males, L females]. The temperature and humidity of the bedroom and bed climate were measured continuously for 24 hours. Bedding and clothing condition, subjective sensational vote and subjective sleep evaluation were surveyed before and after sleep for five days continuously. In the daytime, bedroom and bed climate temperature was significantly lower in H females than in the other groups. At night, no significant effect of gender and ADL was observed in bed climate, which was maintained at 33-35 degrees C, RH50-60% in all the groups. Bedding under the body increased significantly in L males and L females compared with H males and H females. The number of underwear increased significantly in H females. Subjective sleep evaluation was significantly better in H females than the other groups. These results suggest that ADL and gender based differences should be taken into account with regard to the care of the elderly in a nursing home.

Activities of Daily Living↗
PubMed1998

An epidemiological study on the association between the total leukocyte and neutrophil counts, and risk factors of ischemic heart disease by smoking status in Japanese factory workers.

Several epidemiologic studies have shown the association between total leukocyte count and the risk of developing myocardial infarction. The purpose of this study was to assess the association between the total leukocyte and neutrophil counts and risk factors of ischemic heart disease in 1,384 Japanese factory workers. Total leukocyte and neutrophil counts were significantly higher in current smokers than in non-smokers. Among current smokers, the total leukocyte and neutrophil counts were positively associated with the number of cigarettes smoked daily and the duration of cigarette smoking and alcohol consumption. Being independent of smoking habit, the total leukocyte and neutrophil counts were also related to several characteristics recorded at the physical examinations. The total leukocyte and neutrophil counts were positively associated with serum total cholesterol, serum triglyceride and hematocrit levels, and inversely associated with the serum HDL-cholesterol level. No significant associations of the total leukocyte or neutrophil counts were found with the red blood cell count and hemoglobin level. These results suggest that the total leukocyte and neutrophil counts may represent the metabolic condition with a high coronary risk among apparently healthy people.

Adult↗
PubMed2003

Quantitation of house dust mites and house dust mite allergens in the microenvironment of dogs.

OBJECTIVE: To quantitate the density of Dermatophagoides farinae and D pteronyssinus and concentrations of house dust mite (HDM) allergens (Der f 1, Der p 1, and Group 2 allergens) in the indoor microenvironment of dogs. Sample Population-50 homes in Columbus, Ohio. PROCEDURES: n each home, samples of dust were collected from 3 locations in which dogs spent most time. Whenever possible, the species of mites collected was identified. Mite density (mites/g of dust) was assessed, and allergen concentrations were assayed by standardized ELISAs. Relative humidity and temperature in each home were monitored during a 5-day period. Characteristics of homes and sample sources were evaluated. RESULTS: Dust samples from all 50 homes contained > or = 1 HDM allergen; Der f 1 and Der p 1 were detected in 100 and 74% of homes, respectively. Fifteen homes had HDMs; compared with D pteronyssinus, D farinae was found more commonly (14/15 homes) and at a higher density. Basements, homes without central air-conditioning, and dog beds that were > or = 1 year old had high HDM allergen concentrations. Homes with > or = 2 microg of Der f 1 or Group 2 allergens/g of dust or > or = 100 mites/g of dust were significantly more likely to have a maximum relative humidity > or = 75%. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate the presence of HDMs and HDM allergens in the specific microenvironment of dogs in homes. Factors associated with high levels of exposure were identified, which may be associated with increased risk for sensitization and development of atopic diseases.

Allergens↗
PubMed1986

Cold resistance and environmental temperature preference in diarrheic piglets.

Piglets aged 12 to 72 h in which diarrhea had been induced by enteric Escherichia coli infection or sucrose gavage were studied with respect to cold resistance and thermal-circulation index in a 90-min test in a 6 C environment (Exp. 1) and free-choice environmental-temperature preference during a 60-min test in a 24 to 44 C thermocline (Exp. 2). In Exp. 1, diarrhea lowered the piglet's ability to maintain body temperature during the cold test. Also, diarrheic piglets tended to have lower thermal circulation index values at the end of the cold test, indicative of a greater vasoconstrictive response to the cold environment. In Exp. 2, mean preferred environmental temperatures were 35.7, 34.9 and 34.5 C, respectively, for piglets in sham-control, E. coli-infected and sucrose-gavaged groups. For reason(s) still unknown, diarrheic piglets did not choose to locate themselves in a warmer niche than did normal piglets; in fact, they did the opposite. Results of the two experiments indicate that diarrheic neonatal piglets need even more attention and care in terms of the thermal environment than do healthy ones.

Acclimatization↗
PubMed1981

Haemolymph pressure regulation in Porcellio laevis Latr. (Porcellionidae, Isopoda).

Hydrostatic pressure in the haemocoele in Porcellio laevis adults ranges between 3.69 to 12.92 mm Hg (50 to 175 mm H2O). Mechanism involved in haemolymph pressure regulation includes characteristic contractions of intersegmental body musculature. The effects of temperature, humidity, decapitation, destruction of thoracic ganglion, and the injection of insect Ringer and eserine into the haemocoele on intersegmental muscular contractions were studied. The significance of these findings is discussed.

Animals↗
PubMed1986

Effects of dose of antigen and social environment on antibody response of high and low antibody response chickens.

Chickens selected for high (HA) and low (LA) antibody response were exposed to 10-fold doses of red blood cell and killed bacterial antigens while in three different social environments. Antibody responses of the HA and LA line chickens differed most in the socialized environment and at lower doses of antigen. Dose effects were most pronounced in LA-line chickens whereas relationship of humans to chickens was most important to HA-line chickens. Socialized chickens were more consistent than ignored chickens in their response to successive antigens. Correlation between antibody response to red blood cell antigen and Mycoplasma gallisepticum lesions was stronger among socialized chickens than among ignored chickens.

Animals↗
PubMed1986

Effects of broiler litter volatiles and ammonia on fungal spore germination.

The effects of broiler litter volatiles on spore germination of 12 fungal species were determined. The volatiles inhibited spore germination of all species except Scopulariopsis brevicaulis. The inhibitory effect was fungistatic. The inhibitory volatile substances in litter were higher in built-up litter than in freshly used litter and were soluble in an acid solution. Ammonia was identified by infrared analysis as a fungal inhibitory substance in litter. The effect of various concentrations of ammonia produced from ammonium chloride (NH4Cl) was studied, and it was determined that concentrations of ammonia below 150 micrograms/g dry weight of litter were fungistatic for most species. At higher concentrations, ammonia was fungitoxic, with the exception of S. brevicaulis whose spore germination was not inhibited at this high concentration. Fungitoxic levels of ammonia were not found in the litter samples, but broiler house conditions necessary to produce fungitoxic levels are discussed.

Ammonia↗
PubMed1986

Relationship of photoperiod and feed intake to thyroid hormone concentration.

Broilers, obtained from a commercial hatchery, were reared in two environmental chambers with controlled temperature, humidity, and lighting in three trials. Lighting was continuous for 0 to 7 days and 12L:12D thereafter. Temperatures, initially 32.2 C in Trials 1 and 3 and 29.4 in Trial 2, were gradually lowered during rearing. At the end of the trials, temperatures were 21.1, 10.0, and 23.9 C in Trials 1, 2, and 3, respectively. Feed and water were provided ad libitum until 21 days in Trials 1 and 3 and 28 days in Trial 2. During the subsequent 14 days in each trial, feed was provided 12 hr/day with one chamber receiving feed during photophase (LF) and the other receiving feed during scotophase (DF). Plasma samples for 3,5,3'-triiodothyronine (T3) and thyroxine (T4) assay were obtained at 3-hr intervals throughout a 24-hr period at the end of the 14-day treatment period. During the 14-day treatment period, the weight gain of the DF broilers averaged 90% of the LF broilers for the three trials. This demonstrates broilers adapted very well to feeding during scotophase. The T4/T3 ratio increased during fasting and decreased when feed was available, but photoperiod had no discernible effect. The change in T4/T3 ratio over 24 hr was greater at high than at low environmental temperatures.

Animals↗