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Biomedical subjects

C L Hake

Publications and source records attributed to C L Hake.

9 recordsLinked to original sources
PubMed1982

1,1,1-Trichloroethane exposure, biologic monitoring by breath and urine analyses.

Absorption and excretion of 1,1,1-trichloroethane, as well as the kinetics of formation and elimination of trichloroethanol (TCE) and trichloroacetic acid (TCA) were simulated by a mathematical model. The results of this model were compared with experimental one on pulmonary elimination of the solvent and urinary excretion of the metabolites. The influences of duration and repetition of exposure on the pulmonary and urinary eliminations were studied. A tentative method of biologic monitoring is proposed. Theoretically, the most suitable method of biologic monitoring is proposed. Theoretically, the most suitable method to estimate the exposure is by two determinations, before and after a work shift. Following this procedure, analysis of TCE in the urine is more sensitive than determination of 1,1,1-trichloroethane in the breath. As an indicator of exposure risk, TCA is not considered sensitive enough if variations in the inspired concentration occur.

Breath Tests↗
PubMed1977

Human exposure to tetrachloroethylene: inhalation and skin contact.

There is considerable potential for worker exposure to tetrachloroethylene, both by skin contact and by inhalation, during its use in dry cleaning and degreasing operations. This paper reviews accounts of both accidental overexposures of workers and controlled exposures of human subjects by these two routes of exposure. Several reported cases of accidental overexposure to anesthetic doses of the chemical reveal that recovery was generally complete but prolonged, and accompanied by many days of measurable levels of the chemical in the patient's alveolar breath. Chronic overexposures of workmen have lessened since the general acceptance by the Western world of the recommended TLV of 100 ppm for 8 hr of daily exposure. Controlled inhalation studies with volunteer subjects at this level of exposure revealed no effects upon health but did indicate a slight decrement in performance on a coordination test. Additional behavioral and neurological tests revealed no interactive effects when alcohol or diazepam, two depressant drugs, were added singly to tetrachloroethylene exposures. Individual susceptibility to the vapor of this chemical, as evidenced by subjective complaints, was noted in approximately one of ten subjects. The authors conclude that the TLV concentration of 100 ppm in the workplace has a negligible margin of safety regarding unimpaired performance during repeated exposures which could be especially hazardous if the worker is physically active or is in a situation where skin absorption presents an added burden.

Environmental Exposure↗
PubMed1976

Paint-remover hazard.

The in-home use of paint removers containing methylene chloride results in the absorption of this solvent, which is metabolized to carbon monoxide. Exposure for two to three hours can result in the elevation of carboxyhemoglobin (COHb) to levels that stress the cardiovascular system. The metabolic formation of COHb continues following the paint-remover exposure, doubling the duration of the cardiovascular stress produced by a comparable COHb level after exposure to CO. Patients with diseased cardiovascular systems may not be able to tolerate this unexpected stress.

Adult↗
PubMed1976

Use of breath analysis to monitor methylene chloride exposure.

Twenty male and female subjects were exposed repetitively to methylene chloride (CH2Cl2) vapor, 50, 100, 250, and 500 ppm, for 1,3, or 7.5 h in a controlled-environment chamber. Postexposure alveolar breath samples were collected in small glass breath tubes and analyzed for CH2Cl2 by gas chromatography. From these data is a series of breath CH2Cl2 excretion curves were constructed that can be used to estimate the magnitude of a recent exposure. The CH2CL2 breath concentration in the immediate postexposure period accurately reflected the vapor concentration to which the subjects had been exposed most recently. Breath samples collected 1--2 h following exposure were accurate indicators of the time-weighted average vapor exposure experienced by the subjects during the previous 8 h of occupational exposure. Breath analysis offers a practical, noninvasive method for monitoring occupational exposure to CH2Cl2.

Adult↗
PubMed1974

"Degreaser's flush".

Explore the source record for details and available documents.

Atmosphere Exposure Chambers↗
PubMedDate not supplied

Carboxyhemoglobin trend in Chicago blood donors, 1970-1974.

An 18% reduction in the carboxyhemoglobin (HbCO) saturation in nonsmoking Chicago blood donors occurred between 1970 and 1974, indicating that current donors are being exposed to a lower average carbon monoxide (CO) concentration than had been experienced by 1970 donors. In contrast to the situation in 1970, when it was discovered that 74% of the nonsmokers in Chicago were being exposed to CO in excess of the amount permitted by the federal air quality standards, in 1974 only 41% of the nonsmokers were being overexposed. The observed reduction in HbCO correlates well with both the ambient CO levels recorded at the air monitoring stations and the reduction in CO emission from automobiles. If the current trend continues, Chicago should reach compliance with air quality standards for CO by 1985. The measurement of HbCO in a representative urban population is an accurate index of actual CO exposure and supplements the air pollution data provided by air monitoring stations.

Air Pollutants↗