Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Inhalation Exposure”

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.

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

At least 649 records · Page 36Linked to original sources
PubMedDate not supplied

Chronic, inhalation exposure of rats, rabbits, and monkeys to 1,2,4-trichlorobenzene.

Three groups composed of rats, rabbits, and monkeys were exposed for 26 weeks to 1,2,4-trichlorobenzene (-TCB), and one group of each species was used as a control group. The nominal exposure concentrations of 1,2,4-TCB were 25.0, 50.0, and 100.0 ppm. Pulmonary function and operant behavior tests in monkeys, ophthalmoscopic examinations in rabbits and monkeys, and measurement of body weights and hematologic and serum biochemical determinations in all species were conducted before and during the exposure period. At termination of 1, 3, and 6 months of exposure, microscopic examination of selected rat tissues was performed. Microscopic changes were seen in the parenchymal of livers and kidneys from all groups of rats exposed to 1,2,4-TCB when sacrificed after 4 and 13 weeks of exposure, but no exposure-related abnormalities or other effects were seen after 26 weeks of exposure in any species.

Animals↗
PubMed1977

Alopecia induced by inhalation exposure to phenyl glycidyl ether.

Rats and dogs were exposed to heated phenyl glycidyl ether (310 degrees C) vapor at average levels of 1.3, 5.0, and 11.8 ppm (v/v) for 6 hr/day, 5 days/wk, for 90 days. No adverse effects were observed in the dogs and rats other than alopecia in rats at the dose levels of 5.0 and 11.8 ppm. Microscopically, the skin lesions revealed slight acanthosis, hyperkeratosis, and occasional patchy parakeratosis in the epidermis. Follicular keratin plugs were observed with hyperkeratosis of epithelium in the hair follicles and sebaceous glands. Inflammatory reaction was mainly confined to the perifollicular region and affected the hair follicles, resulting in atrophy. The number of hair follicles in the resting stage appeared to increase. The hair shafts revealed impairment of keratinization and fragmentation. Extracted hairs showed an increase in the number of dystrophic follicles and constricted or broken hair shafts.

Alopecia↗
PubMed1985

Cadmium inhalation exposure estimates: their significance with respect to kidney and liver cadmium burden.

Cadmium exposure histories based on employment records, area monitoring techniques, and personal sampling data were obtained for 82 industrially exposed workers. From these data, a time-weighted cumulative exposure index (TWE) was calculated for each worker by multiplying the length of time (ti) in a given work area by the estimated exposure conditions for that area and year (Ei) and then summing these values for the total exposure history TWE = sigma iEiti The cadmium body burden for each worker was measured directly by the in vivo prompt-gamma neutron activation technique. The cadmium content of the left kidney and the liver were measured. For the actively employed workers, a significant correlation (r = 0.70, p less than 0.001) was observed between the exposure index (TWE) and the liver cadmium burden. Furthermore, whenever the worker's liver burden exceeded 40 ppm and the exposure index exceeded 400-500 micrograms/m3 X yr, there was evidence of renal abnormalities (usually elevated urinary beta 2-microglobulin). The highest correlation (r = 0.83, p less than 0.001) was obtained between the kidney cadmium burden data and the exposure index for the active workers without evidence of kidney dysfunction. The percentage of workers with renal abnormalities was found to increase as the exposure index increased. When this relationship was examined using linear logistic regression analysis, the following model was indicated: logit p = 1.24 In TWE--8.34 where p is the individual worker's probability of being classified as having renal dysfunction.

Adult↗
PubMed1987

Effects of intermittent inhalation exposures to mixed atmospheres of NO2 and H2SO4 on rabbit alveolar macrophages.

Rabbits were exposed (2h/d) to atmospheres consisting of 0.5 mg/m3 (0.3 micron) H2SO4 plus NO2 at either 0.3 (low) or 1 ppm (high). Animals were sacrificed 24 h after 2, 6, or 13 exposures, and cells were recovered from the lungs by bronchopulmonary lavage. Exposure to high NO2 with acid resulted in an increase in neutrophils at all time points and an increase in phagocytic capacity of macrophages after two or six exposures. On the other hand, exposure to the low NO2 with acid resulted in depressed phagocytic capacity and mobility. The results were compared with those for NO2 or H2SO4 given alone.

Animals↗
PubMed1979

Three-month inhalation exposure study with methane sulfonylfluoride.

The effects of exposure to methane sulfonylfluoride at concentrations of 20 or 100 ppb for a total of 61 exposures of 7 hours each were studied in male and female rats. The control and exposed groups did not differ in appearance, behavior, weight gain or food consumption. There was no effect on plasma cholinesterase. RBC cholinesterase was significantly depressed in the high-level male and female exposure groups. There was no significant accumulation of fluoride in either the liver or blood at either exposure level.

Aerosols↗
PubMed1983

Inhalation exposure of lead in brass foundry workers: the evaluation of the effectiveness of a powered air-purifying respirator and engineering controls.

The protection that a powered air-purifying respirator afforded to ladle and furnace attendants who were exposed to lead, copper and zinc fumes in a brass foundry was found by measuring metal levels at the lapel and at nose level inside the respirator. Respirator fit was evaluated by use of a hot-wire anemometer at the face/Tyvek seal interfaces, and at the exit of the respirator. Effective protection factors for lead ranged from 1.05 to 67. Ergonomic factors and engineering controls are also discussed.

Air Pollutants, Occupational↗
PubMed1984

A double isotope method for characterizing hygroscopic selenious acid aerosols used in inhalation exposures.

Methods of generating and characterizing selenious acid aerosols for use in deposition and toxicity studies are described. Selenious acid aerosols were nebulized and heat treated at varied temperatures. Because selenious acid is hygroscopic, a solution containing 3H2O and 75Se was nebulized to determine the water content in selenium aerosols after generation. The stable aerosol was a hydrate of selenious acid, H2SeO3 X 1/2 H2O, at New Mexico ambient relative humidity (ca. 20%). The mass median aerodynamic diameter of the collected droplets was 0.6 micron with a geometric standard deviation of 1.3.

Aerosols↗
PubMed1984

Inhalation exposure to formaldehyde: an overview of its toxicology, epidemiology, monitoring, and control.

Increasing production and use of formaldehyde in consumer products have resulted in widespread recognition of its acute irritant effects at exposure levels below the current occupational health standard [3 parts per million parts of air (ppm)]. Formaldehyde is an allergic (immunologically mediated) skin sensitizer which may also cause or exacerbate respiratory distress in individuals with preexisting or formaldehyde-induced bronchial hyperreactivity. Formaldehyde gas is a very reactive alkylating agent which is mutagenic in several in vitro test systems. At exposure levels less than one order of magnitude greater than those often found in human occupational and nonoccupational environments, it induces squamous cell carcinomas in the nasal cavity of rats. Recent reviews suggest that formaldehyde exposure should be treated as though it poses a carcinogenic risk to humans and should be reduced to the lowest feasible level. This report reviews information on the epidemiologic evaluation of health effects which may result from hazardous levels of exposure to formaldehyde. Methods for monitoring exposure are discussed in detail because of considerable diversity in the methods used by state health departments for recognition, evaluation and control of nonoccupational exposures. Current guidelines for the evaluation and control of exposures to formaldehyde gas are suggested.

Acute Disease↗
PubMed1986

Resuspension of dust from work clothing as a source of inhalation exposure.

Workshirts which had been worn by employees at a beryllium refinery were tested to assess whether wear significantly affects the amount of resuspended Be containing dust. Sections of six work shirts--three "new" (one washed, two unwashed) and three "old" (one washed, two unwashed)--were analyzed to measure the concentration of Be in the fabric. Additional swatches were agitated to resuspend Be particles inside a closed steel glove box. Air samples were taken with filter cassette monitors. After sampling, the fabric and filter samples were analyzed for beryllium. As a group, the old shirts resuspended significantly higher quantities of Be to the air than did the washed and unwashed new shirts. A considerable fraction of the Be measured in air was respirable.

Air↗
PubMed1989

Dust inhalation exposures from the handling of small volumes of powders.

Worker exposure to airborne particulates was stimulated in a laboratory under controlled conditions. Small volumes, 3.8 L (1 gal.), of finely divided powders were transferred at 1-min intervals to 23-L (6-gal.) containers over 30-min time intervals. A high-volume filter array in the exit vent of the specially designed exposure laboratory was used both to control the ventilation rate and to determine the emission factor of the pouring operation. The room ventilation rate, method of transfer, and drop height were varied, and the resulting particulate concentrations were monitored by personal and area samplers. The four powders studied were talc, sodium chloride, Portland cement, and Direct Yellow 4 dye. Based on this study, a model was developed to predict potential worker exposure from the pouring of small volumes of powders. The model is based on the following major conclusions. First, the space- and time-averaged concentration of suspended particulate matter at breathing height agrees well with the mean concentration of suspended particulate matter in the room air effluent. Second, material-specific suspended particulate emission factors vary approximately in direct proportion to the drop height. Third, emission factors for scooping/dumping operations agree well with factors for pouring operations for a given drop height. Fourth, emission factors compare well with dustiness indexes that were determined using a bench-scale dustiness test chamber described in a companion paper. Parameters of the exposure model include dustiness index, drop height of the pouring operation, total quantity of material poured, averaging time, and the fraction of respirable material. For the validation of the model, additional data would be necessary.

Air Pollutants, Occupational↗